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Sample records for andean basin pattern

  1. Dynamic paleogeography of the Jurassic Andean Basin: pattern of transgression and localisation of main straits through the magmatic arc

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    J-C. Vicente

    2005-03-01

    Full Text Available The paleogeographic evolution of the Jurassic Andean retroarc basin is examined at a global scale for the Central Andes. In this paper, it is called for the striking continuity and lasting of the active volcanic arc. Both direct and indirect sedimentologic evidences allow to locate the western border (insular of the basin and opposite it with the eastern border (cratonic. Emphasis is placed on the volcaniclastic deposits and synsedimentary structures associated with this insular border. It is concluded that the arc magmatic activity has contributed considerably in sediment supply to the basin. Extent and continuity of the arc implies to locate the straits connecting with the Paleopacific. Systematic check of the time of transgressions coupled with sequential facies analysis provides a dynamic outlook of the transgressive process. Sectors with early transgression allow to distinguish two main gulfs of passage through the arc from which waters have progressed lengthwise at the same time northward and southward in a narrow retroarc furrow : the first at latitude of Taltal (25°S, the second at latitude of Curepto (35°S. Both initiated in the upper Triassic and extended during the Hettangian. The evolution as separate basins (Tarapacá and Aconcagua-Neuquén ended by fusion in middle Pliensbachian giving rise to a continuous elongated basin from Chubut to northern Peru. The remarkable continuity and narrowness of the Andean Basin leaves no doubt about its tectonic control. This stems to its geotectonic setting as a typical retroarc basin adjacent to a very active magmatic arc and explains the extreme mobility of its insular margin characterized by a huge volcanoclastic apron with associated debris flows and turbidites.

  2. Climate Change Impacts in a Colombian Andean Tropical Basin

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    Ocampo, O. L.; Vélez, J. J.; Londoño, A.

    2012-12-01

    Climate change and climate variability have a large impact on water resources. Developing regions have less capacity to prepare for, respond to, and recover from climate-related hazards and effects, and then, populations may be disproportionately affected. In Colombia, the geographical location and the marked irregularity in the terrain, give as a result, a complex climate. These factors have contributed to the water supply of the territory. Unfortunately, the visualization of abundant and inexhaustible water resources created a great disregard for them. Besides, the water supply is not distributed uniformly across the country, and then there is water-deficit in some areas as Andean Region, where the largest population and the main development centers are located. In recent decades, water conflicts have emerged locally and regionally, which have generated a crisis in the allocation mechanisms and have improved the understanding of the water situation in Colombia. The Second National Communication to CCMNU alerts on possible future consequences of climate change and the need for regional studies for understanding climate change impacts on the fragile ecosystems of high mountains as paramos and fog forest, which are water production regulators. Colombian water resources are greatly affected by changes in rainfall patterns influenced by El Niño and La Niña. The recent disasters in the 2010-2011 rainy seasons have caught the attention of not only the authorities but from the scientific community to explore strategies to improve water management by tracking, anticipating and responding to climate variability and climate change. Whereas sound water management is built upon long-term, the country is undertaking a pilot exercise for the integrated management of water resources, five Basins are selected, among them, is the Chinchiná River Basin; this Andean tropical Basin is located on the western slopes at the central range in the Andes between 4°48 and 5°12 N

  3. Hydrochemical and isotopic patterns in a calc-alkaline Cu- and Au-rich arid Andean basin: The Elqui River watershed, North Central Chile

    International Nuclear Information System (INIS)

    Highlights: ► Major ions are provided by rock weathering and NaCl recycling. ► Aridity and cal-alkaline lithology effects abate acid drainage. ► Factors affecting hydrochemistry in mineral rich zone are addressed. ► Stable isotopes confirm the meteoric origin of groundwaters. ► High sulfate contents are explained by widespread sulfide minerals. - Abstract: The geochemistry of surface water and groundwater from the Elqui River basin, North-Central Chile, was studied in spring 2007 and fall 2008 to obtain a general understanding of the factors and mechanisms controlling the water chemistry of steep rivers located in mineral-rich, arid to semi arid zones. Besides its uniform intermediate igneous lithology, this basin is known for acid drainage and high As contents in the El Indio Au–Cu–As district, in its Andean head. Abundant tailings deposits are present in the middle part of the basin, where agricultural activities are important. According to the results, the chemical and isotopic composition of the Elqui basin surface water and groundwater is related to uniform calc-alkaline lithology and the major polluting system of the chemically reactive, but closed El Indio mining district. The resulting compositional imprints in surface and ground-water are, (a) high SO4 levels, reaching about 1000 mg/L in the Toro River water, directly draining the mining area; (b) a major depletion of Fe and pollutant metals in surface water after the confluence of the Toro and La Laguna rivers; (c) similar chemical composition of surface and ground-waters that differ in H and O isotopic composition, reflecting the effect of differential evaporation processes downstream of the Puclaro dam; and (d) seasonal variations of Fe, Mn, Cu and Zn in surface water. In contrast, the groundwater chemistry exhibits moderate seasonal changes, mainly in HCO3- content. In spite of the acid drainage pollution, water quality is adequate for human consumption and irrigation. This is a

  4. Sediment budget in the Ucayali River basin, an Andean tributary of the Amazon River

    OpenAIRE

    W. Santini; Martinez, J. -M.; Espinoza-Villar, R.; G. Cochonneau; Vauchel, P.; Moquet, J.-S.; Baby, P.; Espinoza, J.-C.; Lavado, W.; Carranza, J.; Guyot, J.-L.

    2015-01-01

    Formation of mountain ranges results from complex coupling between lithospheric deformation, mechanisms linked to subduction and surface processes: weathering, erosion, and climate. Today, erosion of the eastern Andean cordillera and sub-Andean foothills supplies over 99% of the sediment load passing through the Amazon Basin. Denudation rates in the upper Ucayali basin are rapid, favoured by a marked seasonality in this region and extreme precipitation cells above sedimentary strata, uplifted...

  5. Sediment budget in the Ucayali River basin, an Andean tributary of the Amazon River

    Science.gov (United States)

    Santini, W.; Martinez, J.-M.; Espinoza-Villar, R.; Cochonneau, G.; Vauchel, P.; Moquet, J.-S.; Baby, P.; Espinoza, J.-C.; Lavado, W.; Carranza, J.; Guyot, J.-L.

    2015-03-01

    Formation of mountain ranges results from complex coupling between lithospheric deformation, mechanisms linked to subduction and surface processes: weathering, erosion, and climate. Today, erosion of the eastern Andean cordillera and sub-Andean foothills supplies over 99% of the sediment load passing through the Amazon Basin. Denudation rates in the upper Ucayali basin are rapid, favoured by a marked seasonality in this region and extreme precipitation cells above sedimentary strata, uplifted during Neogene times by a still active sub-Andean tectonic thrust. Around 40% of those sediments are trapped in the Ucayali retro-foreland basin system. Recent advances in remote sensing for Amazonian large rivers now allow us to complete the ground hydrological data. In this work, we propose a first estimation of the erosion and sedimentation budget of the Ucayali River catchment, based on spatial and conventional HYBAM Observatory network.

  6. Developing tools to evaluate the environmental status of Andean basins with mining activities

    OpenAIRE

    Yacoub López, Cristina

    2013-01-01

    The water quality status of an Andean river basin was characterised and the pressures from anthropogenic activities were evaluated to enhance the available knowledge of the environment within an ecosystem in Peru. This investigation was conducted to assess the environmental status of the basin as a first step to introducing river management plans and specific water quality programmes. A continuous simulation model and an environmental monitoring program were developed, taking into account the...

  7. Evolution of the Neogene Andean foreland basins of the Southern Pampas and Northern Patagonia (34°-41°S), Argentina

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    Folguera, Alicia; Zárate, Marcelo; Tedesco, Ana; Dávila, Federico; Ramos, Victor A.

    2015-12-01

    The Pampas plain (30°-41°S) has historically been considered as a sector that evolved independently from the adjacent Andean ranges. Nevertheless, the study of the Pampas showed that it is reasonable to expect an important influence from the Andes into the extraandean area. The Pampas plain can be divided into two sectors: the northern portion, adjacent to the Pampean Ranges, has been studied by Davila (2005, 2007, 2010). The southern sector (34°-41°S) is the objective of the present work. The study of this area allowed to characterize two separate foreland basins: the Southern Pampa basin and the Northern Patagonian basin. The infill is composed of Late Miocene and Pliocene units, interpreted as distal synorogenic sequences associated with the late Cenozoic Andean uplift at this latitudinal range. These foreland basins have been defined based on facies changes, distinct depositional styles, along with the analysis of sedimentary and isopach maps. The basins geometries are proposed following De Celles and Gilles (1996) taking into account the infill geometry, distribution and grain size. In both cases, these depocenters are located remarkably far away from the Andean tectonics loads. Therefore they cannot be explained with short-wave subsidence patterns. Elastic models explain the tectonic subsidence in the proximal depocenters but fail to replicate the complete distal basins. These characteristics show that dynamic subsidence is controlling the subsidence in the Southern Pampas and Northern Patagonian basins.

  8. Tectonic and paleoenvironmental evolution of Mesozoic sedimentary basins along the Andean foothills of Argentina (32°-54°S)

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    Franzese, Juan; Spalletti, Luis; Pérez, Irene Gómez; Macdonald, David

    2003-05-01

    Chronoenvironmental and tectonic charts are presented for Mesozoic basins located along the Andean foothills of the South American plate. On the basis of the main tectonic events, pre-Andean basins, break-up-related basins, extensional back-arc basins, and Andean foreland basins are recognized. The pre-Andean basins were formed by continental extension and strike-slip movement before the development of the Mesozoic-Cenozoic Andean magmatic arc. Upper Permian to Middle Triassic extension along Palaeozoic terrane sutures resulted in rifting, bimodal magmatism (Choiyoi group), and continental deposition (Cuyo basin). From the Late Triassic to the Early Jurassic, continental extension related to the collapse of the Gondwana orogen initiated a series of long, narrow half-grabens that filled with continental volcaniclastic deposits. These depocenters were later integrated into the Neuquén basin. Coeval development of the shallow marine Pampa de Agnia basin (42-44°S) is related to short-lived extension, probably driven by dextral displacement along major strike-slip faults (e.g. the Gastre fault system). Widespread extension related to the Gondwana breakup (180-165 Ma) and the opening of the Weddell Sea reached the western margin of the South American plate. As a result, wide areas of Patagonia were affected by intraplate volcanism (Chon Aike province), and early rifting occurred in the Magallanes basin. The Andean magmatic arc was almost fully developed by Late Jurassic times. A transgressive stage with starvation and anoxia characterized the Neuquén basin. In western Patagonia, back-arc and intra-arc extension produced the opening of several grabens associated with explosive volcanism and lava flows (e.g. Rı´o Mayo, El Quemado). To the south, a deep marginal basin floored by oceanic crust (Rocas Verdes) developed along the back-arc axis. In mid-to late Cretaceous times, Andean compressional tectonics related to South Atlantic spreading caused the inversion of

  9. Erosion of particulate organic material from an Andean river and its delivery to the Amazon Basin

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    Clark, Kathryn; Hilton, Robert; West, A. Joshua; Robles Caceres, Arturo; Grocke, Darren; Marthews, Toby; Asner, Greg; New, Mark; Mahli, Yadvinder

    2016-04-01

    Organic carbon and nutrients discharged by mountainous rivers can play an important role in biogeochemical cycles from regional to global scales. The eastern Andes host productive forests on steep, rapidly eroding slopes, a combination that is primed to deliver sediment, carbon and nutrients to the lowland Amazon River. We quantify clastic sediment and particulate organic carbon (POC) discharge for the Kosñipata River, Peru, an Andean tributary of the Madre de Dios River, using suspended sediment samples and discharge measurements over one year at two gauging stations. Calculations of sediment yield on the basis of this data suggest that the Madre de Dios basin may have erosion rates ˜10 times greater than the Amazon Basin average. The total POC yield over the sampling period was up to five times higher than the yield in the lowland Amazon Basin, with most POC (70-80%) exported between December and March in the wet season. We use radiocarbon, stable C isotopes and C/N ratios to distinguish between the erosion and discharge of POC from sedimentary rocks (petrogenic POC) and POC eroded from the modern terrestrial biosphere, from vegetation and soil (biospheric POC). We find that biospheric POC discharge was significantly enhanced during flood events, over that of clastic sediment and petrogenic POC. The ultimate fate of the eroded POC may play a central role in the net carbon budget of Andean forest. In these forests, net productivity minus heterotrophic respiration is close to zero at the scale of forest plots, and the erosion of biospheric POC by this Andean river is sufficiently rapid that its fate downstream (sedimentary burial/preservation versus oxidation/degradation) may determine whether the mountain forest is a carbon sink or source to the atmosphere. In addition, the measured discharge of petrogenic POC suggests that fluxes from the Andes may be considerably higher than measured downstream in the Madeira River. If this petrogenic POC is oxidised rather

  10. Adaptation and mal-adaptation to ambient hypoxia; Andean, Ethiopian and Himalayan patterns.

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    Guoqiang Xing

    Full Text Available The study of the biology of evolution has been confined to laboratories and model organisms. However, controlled laboratory conditions are unlikely to model variations in environments that influence selection in wild populations. Thus, the study of "fitness" for survival and the genetics that influence this are best carried out in the field and in matching environments. Therefore, we studied highland populations in their native environments, to learn how they cope with ambient hypoxia. The Andeans, African highlanders and Himalayans have adapted differently to their hostile environment. Chronic mountain sickness (CMS, a loss of adaptation to altitude, is common in the Andes, occasionally found in the Himalayas; and absent from the East African altitude plateau. We compared molecular signatures (distinct patterns of gene expression of hypoxia-related genes, in white blood cells (WBC from Andeans with (n = 10, without CMS (n = 10 and sea-level controls from Lima (n = 20 with those obtained from CMS (n = 8 and controls (n = 5 Ladakhi subjects from the Tibetan altitude plateau. We further analyzed the expression of a subset of these genes in Ethiopian highlanders (n = 8. In all subjects, we performed the studies at their native altitude and after they were rendered normoxic. We identified a gene that predicted CMS in Andeans and Himalayans (PDP2. After achieving normoxia, WBC gene expression still distinguished Andean and Himalayan CMS subjects. Remarkably, analysis of the small subset of genes (n = 8 studied in all 3 highland populations showed normoxia induced gene expression changes in Andeans, but not in Ethiopians nor Himalayan controls. This is consistent with physiologic studies in which Ethiopians and Himalayans show a lack of responsiveness to hypoxia of the cerebral circulation and of the hypoxic ventilatory drive, and with the absence of CMS on the East African altitude plateau.

  11. Diversity patterns, environmental drivers and changes in vegetation composition in dry inter-Andean valleys

    DEFF Research Database (Denmark)

    Quintana, Catalina; Girardello, Marco; Barfod, Anders;

    2016-01-01

    Aims We studied diversity, patterns of endemism and turnover of vegetation composition in dry inter-Andean valleys (DIAVs) where little is known about the influence of the abiotic drivers controlling plant species composition and occurrences, and the life forms that contribute most to α- and β......-diversity correlated with latitude? (iii) what are the major environmental drivers controlling spatial patterns in species composition and occurrence? Methods We established 63 transects of 5 × 100 m in areas with DIAV vegetation, impacted as little as possible by human activities. In each transect, all mature trees...

  12. Ancient DNA reveals kinship burial patterns of a pre-Columbian Andean community

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    Baca Mateusz

    2012-04-01

    Full Text Available Abstract Background A detailed genetic study of the pre-Columbian population inhabiting the Tompullo 2 archaeological site (department Arequipa, Peru was undertaken to resolve the kin relationships between individuals buried in six different chullpas. Kin relationships were an important factor shaping the social organization in the pre-Columbian Andean communities, centering on the ayllu, a group of relatives that shared a common land and responsibilities. The aim of this study was to evaluate whether this Andean model of a social organization had an influence on mortuary practices, in particular to determine whether chullpas served as family graves. Results The remains of forty-one individuals were analyzed with both uniparental (mtDNA, Y–chromosome and biparental (autosomal microsatellites markers. Reproducible HVRI sequences, autosomal and Y chromosomal STR profiles were obtained for 24, 16 and 11 individuals, respectively. Mitochondrial DNA diversity was comparable to that of ancient and contemporary Andean populations. The Tompullo 2 population exhibited the closest relationship with the modern population from the same region. A kinship analysis revealed complex pattern of relations within and between the graves. However mean relatedness coefficients regarding the pairs of individuals buried in the same grave were significantly higher than those regarding pairs buried in different graves. The Y chromosome profiles of 11 males suggest that only members of one male line were buried in the same grave. Conclusions Genetic investigation of the population that inhabited Tompullo 2 site shows continuity between pre-Columbian and modern Native Amerindian populations inhabiting the Arequipa region. This suggests that no major demographic processes have influenced the mitochondrial DNA diversity of these populations during the past five hundred years. The kinship analysis involving uni- and biparental markers suggests that the community that

  13. Geodynamic Drivers of Vertical Crustal Motion: Integrating Paleoaltimetry with Basin Development in the Central Andean Plateau of Southern Peru

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    Sundell, K. E., II; Saylor, J. E.; Lapen, T. J.; Villarreal, D. P.; Styron, R. H.; Horton, B. K.; Cardenas, J.

    2015-12-01

    Determining the spatial and temporal relationships between surface uplift, tectonic subsidence, and exhumation during periods of oblique crustal shortening is essential to discriminating geodynamic processes controlling formation of high topography in the central Andes. Although subsidence analysis is now a standard tool, paleoelevation estimation remains a challenging task, as estimates based on proxy data can be complicated by uncertainties in the relative controls of tectonics and climate. We therefore adopt an approach of combining established tools of subsidence analysis and detrital geochronology with emerging methods of volcanic glass paleoaltimetry, which enables us to explore a broad range of viable interpretations to understand the development of intermontane basins and their relationship to the development of the central Andean plateau. We investigated a suite of temporally overlapping and spatially separate Cenozoic basins spanning the east-west extent of the central Andean plateau in southern Peru. These basins contain an exceptional record of the vertical movements of this region. We calculate sediment accumulation and subsidence rates through decompaction of measured stratigraphic sections, and reconstruct past environmental conditions based on the stable isotopic composition of ancient waters preserved in hydrated volcanic glass. These data and published records of crustal shortening and exhumation show that although paleoaltimetry data in the study areas may be interpreted in various ways, they are best explained by multiple geodynamic processes driving (i) Eocene-early Miocene development of high topography in the Western Cordillera, then (ii) a pulsed middle Miocene-present building of the central Andean plateau from west to east, consistent with global climate changes as well as regional climate shifts driven by topographic development of the Andean orogen.

  14. Tracking evolution of Andean ranges bounding the Middle Magdalena Valley basin, Colombia

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    Nie, J.; Horton, B. K.; Mora, A.; Saylor, J.; Housh, T. B.; Rubiano, J.; Naranjo, N.

    2009-12-01

    The shortening history of the northern Andes is important to our understanding of convergent continental deformation. However, the timing of significant shortening-related uplift in the northern Andes is poorly constrained, with estimates ranging from early-Cretaceous to Miocene. Detrital zircon U-Pb ages from the middle Magdelena Valley basin in Colombia reveal two pronounced provenance shifts during the Cenozoic. The first shift occurs between lower and upper Paleocene strata, where age spectra switch from Proterozoic-dominated to Phanerozoic-dominated. We attribute this change to uplift-related exhumation of the Central Cordillera. The second shift occurs between middle-upper Eocene and upper Oligocene strata, where increased Grenville and diminished mid- Jurassic-Cenozoic zircon ages are consistent with initial shortening-related uplift of the Eastern Cordillera. The U-Pb results improve our understanding of the Cenozoic uplift/exhumation history of the Colombian Andes and provide a basis for future studies that consider the possible role of Andean uplift on Cenozoic climate.

  15. Subduction consequences along the Andean margin : thermal and topographic signature of an ancient ridge subduction in the Marañón Basin of Perú

    OpenAIRE

    Baudino, R.; Hermoza, W.

    2014-01-01

    All along the eastern border of the Andes lie foreland basins that are among the most prolific hydrocarbon provinces of the world. Their Cenozoic evolution was controlled by the Andean uplift and its consequences on deformation and sedimentation. In turn, the Andean uplift results from the interplay between the subducting Nazca oceanic plate and the South American continental plate. Although the process exists all along the margin, the subducting plate is not regular including bathymetric ano...

  16. Evaluating the Effects of LULC Changes and Climate Variability in the Hydrological Response of a Tropical Andean River Basin. The Case of the Boconó River Basin - Venezuela

    OpenAIRE

    Mejia Barazarte, Joel Francisco

    2012-01-01

    This research study aimed to analyze the effects of the spatial changes, particularly inherent to the LULC changes in a tropical River Basin, and its possible impact in the water resources - response. The Boconó River Basin, located in the North Venezuelan Andean Region was selected as study area, being a very representative Andean catchment in which the biophysical and the socio-cultural systems are strongly interacting to generate a quite complex dynamic reflected in the form and intensity ...

  17. Diversity patterns of selected Andean plant groups correspond to topography and habitat dynamics, not orogeny

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    Jens eMutke

    2014-10-01

    Full Text Available The tropical Andes are a hotspot of biodiversity, but detailed altitudinal and latitudinal distribution patterns of species are poorly understood. We compare the distribution and diversity patterns of four Andean plant groups on the basis of georeferenced specimen data: the genus Nasa (Loasaceae, the two South American sections of Ribes (sect. Parilla and sect. Andina, Grossulariaceae, and the American clade of Urtica (Urticaceae. In the tropical Andes, these often grow together, especially in (naturally or anthropogenically disturbed or secondary vegetation at middle to upper elevations. The climatic niches of the tropical groups studied here are relatively similar in temperature and temperature seasonality, but do differ in moisture seasonality. The Amotape-Huancabamba Zone (AHZ between 3–8° S shows a clear diversity peak of overall species richness as well as for narrowly endemic species across the groups studied. For Nasa, we also show a particular diversity of growth forms in the AHZ. This can be interpreted as proxy for a high diversity of ecological niches based on high spatial habitat heterogeneity in this zone. Latitudinal ranges are generally larger towards the margins of overall range of the group. Species number and number of endemic species of our taxa peak at elevations of 2,500–3,500 m in the tropical Andes. Altitudinal diversity patterns correspond well with the altitudinal distribution of slope inclination. We hypothesize that the likelihood and frequency of landslides at steeper slopes translates into temporal habitat heterogeneity. The frequency of landslides may be causally connected to diversification especially for the numerous early colonizing taxa, such as Urtica and annual species of Nasa. In contrast to earlier hypotheses, uplift history is not reflected in the pattern here retrieved, since the AHZ is the area of the most recent Andean uplift. Similarly, a barrier effect of the low-lying Huancabamba depression is

  18. Cenozoic stratigraphic development in the north Chilean forearc: Implications for basin development and uplift history of the Central Andean margin

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    Hartley, Adrian J.; Evenstar, Laura

    2010-11-01

    with volcanic activity limited to the periodic eruption of extensive ignimbrite sheets. Alluvial fan, fluvial and lacustrine sedimentation dominated within the endorheic basins from ˜ 8 to 3 Ma. After development of a regional unconformity at 3 Ma a change to isolated evaporite sub-basins took place in the Central Depression with small lacustrine basins developed along the flank of the Western Cordillera. The scale and grain size recorded in the sedimentary systems indicates that a substantial source area was located in the present day area of the Western Cordillera by 30 Ma and that this has persisted to the present day. This area also shed material eastwards into the Altiplano. The presence of such a topographic feature by 30 Ma suggests that a significant proportion of Andean uplift had occurred prior to the Late Miocene. This important uplift phase should be incorporated into any model of Andean uplift. The evidence from the basin-fill succession suggests that sediments accumulated in a basin developed in front of a broad monocline between 38 and 19 Ma and that a transition to a thrust-bounded foreland style basin took place after the development of the unconformity at 19 Ma.

  19. Large-scale patterns of turnover and Basal area change in Andean forests.

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    Selene Báez

    Full Text Available General patterns of forest dynamics and productivity in the Andes Mountains are poorly characterized. Here we present the first large-scale study of Andean forest dynamics using a set of 63 permanent forest plots assembled over the past two decades. In the North-Central Andes tree turnover (mortality and recruitment and tree growth declined with increasing elevation and decreasing temperature. In addition, basal area increased in Lower Montane Moist Forests but did not change in Higher Montane Humid Forests. However, at higher elevations the lack of net basal area change and excess of mortality over recruitment suggests negative environmental impacts. In North-Western Argentina, forest dynamics appear to be influenced by land use history in addition to environmental variation. Taken together, our results indicate that combinations of abiotic and biotic factors that vary across elevation gradients are important determinants of tree turnover and productivity in the Andes. More extensive and longer-term monitoring and analyses of forest dynamics in permanent plots will be necessary to understand how demographic processes and woody biomass are responding to changing environmental conditions along elevation gradients through this century.

  20. Large-Scale Patterns of Turnover and Basal Area Change in Andean Forests

    Science.gov (United States)

    Blundo, Cecilia; Aguilar, Manuel; Aguirre, Nikolay; Aquirre, Zhofre; Álvarez, Esteban; Cuesta, Francisco; Farfán-Ríos, William; García-Cabrera, Karina; Grau, Ricardo; Linares-Palomino, Reynaldo; Malizia, Lucio R.; Cruz, Omar Melo; Osinaga, Oriana; Reynel, Carlos; Silman, Miles R.

    2015-01-01

    General patterns of forest dynamics and productivity in the Andes Mountains are poorly characterized. Here we present the first large-scale study of Andean forest dynamics using a set of 63 permanent forest plots assembled over the past two decades. In the North-Central Andes tree turnover (mortality and recruitment) and tree growth declined with increasing elevation and decreasing temperature. In addition, basal area increased in Lower Montane Moist Forests but did not change in Higher Montane Humid Forests. However, at higher elevations the lack of net basal area change and excess of mortality over recruitment suggests negative environmental impacts. In North-Western Argentina, forest dynamics appear to be influenced by land use history in addition to environmental variation. Taken together, our results indicate that combinations of abiotic and biotic factors that vary across elevation gradients are important determinants of tree turnover and productivity in the Andes. More extensive and longer-term monitoring and analyses of forest dynamics in permanent plots will be necessary to understand how demographic processes and woody biomass are responding to changing environmental conditions along elevation gradients through this century. PMID:25973977

  1. Hydro-meteorological functioning of the Eastern Andean Tropical Montane Cloud Forests: Insight from a paired catchment study in the Orinoco river basin highlands

    Science.gov (United States)

    Ramirez, Beatriz; Teuling, Adriaan J.; Ganzeveld, Laurens; Leemans, Rik

    2016-04-01

    Tropical forests regulate large scale precipitation patterns and catchment-scale streamflow, while tropical mountains influence runoff by orographic effects and snowmelt. Along tropical elevation gradients, these climate/ecosystem/hydrological interactions are specific and heterogeneous. These interactions are poorly understood and represented in hydro-meteorological monitoring networks and regional or global earth system models. A typical case are the South American Tropical Montane Cloud Forests (TMCF), whose water balance is strongly driven by fog persistence. This also depends on local and up wind temperature and moisture, and changes in this balance alter the impacts of changes in land use and climate on hydrology. These TMCFs were until 2010 only investigated up to 350km from the coast. Continental TMCFs are largely ignored. This gap is covered by our study area, which is part of the Orinoco river basin highlands and located on the northern Eastern Andes at an altitudinal range of 1550 to 2300m a.s.l. The upwind part of our study area is dominated by lowland savannahs that are flooded seasonally. Because meteorological stations are absent in our study area, we first describe the spatial and seasonal meteorological variability and analyse the corresponding catchment hydrology. Our hydro-meteorological data set is collected at three gauged neighbouring catchments with contrasting TMCF/grassland cover from June 2013 to May 2014 and includes hourly solar radiation, temperature, relative humidity, wind speed, precipitation, soil moisture and runoff measurements. We compare our results with recent TCMF studies in the eastern Andean highlands in the Amazon basin. The studied elevational range always shows wetter conditions at higher elevations. This indicates a positive relation between elevation and fog or rainfall persistence. Lower elevations are more seasonally variable. Soil moisture data indicate that TMCFs do not use persistently more water than grasslands

  2. Depositional and provenance record of the Paleogene transition from foreland to hinterland basin evolution during Andean orogenesis, northern Middle Magdalena Valley Basin, Colombia

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    Moreno, Christopher J.; Horton, Brian K.; Caballero, Victor; Mora, Andrés; Parra, Mauricio; Sierra, Jair

    2011-10-01

    The Central Cordillera and Eastern Cordillera of the northern Andes form the topographic flanks of the north-trending Magdalena Valley Basin. Constraining the growth of these ranges and intervening basin has implications for Andean shortening and the transformation from a foreland to hinterland basin configuration. We present sedimentological, paleocurrent, and sandstone petrographic results from Cenozoic type localities to provide insights into the tectonic history of the northern Middle Magdalena Valley Basin of Colombia. In the Nuevo Mundo Syncline, the mid-Paleocene transition from marine to nonmarine deposystems of the Lisama Formation corresponds with a paleocurrent shift from northward to eastward transport. These changes match detrital geochronological evidence for a contemporaneous shift from cratonic (Amazonian) to orogenic (Andean) provenance, suggesting initial shortening-related uplift of the Central Cordillera and foreland basin generation in the Magdalena Valley by mid-Paleocene time. Subsequent establishment of a meandering fluvial system is recorded in lower-middle Eocene strata of the lower La Paz Formation. Eastward paleocurrents in mid-Paleocene through uppermost Eocene fluvial deposits indicate a continuous influence of western sediment source areas. However, at the upper middle Eocene (˜40 Ma) boundary between the lower and upper La Paz Formation, sandstone compositions show a drastic decrease in lithic content, particularly lithic volcanic fragments. This change is accompanied by a facies shift from mixed channel and overbank facies to thick, amalgamated braided fluvial deposits of possible fluvial megafans, reflecting changes in both the composition and proximity of western sediment sources. We attribute these modifications to the growing influence of exhumed La Cira-Infantas paleohighs in the axial Magdalena Valley, features presently buried beneath upper Eocene-Quaternary basin fill along the western flank of the Nuevo Mundo Syncline. In

  3. Seismo-stratigraphic evolution of the northern Austral Basin and its possible relation to the Andean tectonics, onshore Argentina.

    Science.gov (United States)

    Sachse, Victoria; Anka, Zahie; Pagan, Facundo; Kohler, Guillermina; Cagnolatti, Marcelo; di Primio, Rolando; Rodriguez, Jorge

    2013-04-01

    , coupled with important basin subsidence at Andes foothills. An E-W transpressive deformation occurred during late Oligocene and Miocene, initiated by significant changes of plate motion between Nazca and South American plate, driving the Quechua phase of the Andean uplift. Hence, enhanced sedimentation from the rising Andes was renewed since a late Miocene unconformity.

  4. Probabilistic Forecasting of Drought Events Using Markov Chain- and Bayesian Network-Based Models: A Case Study of an Andean Regulated River Basin

    Directory of Open Access Journals (Sweden)

    Alex Avilés

    2016-01-01

    Full Text Available The scarcity of water resources in mountain areas can distort normal water application patterns with among other effects, a negative impact on water supply and river ecosystems. Knowing the probability of droughts might help to optimize a priori the planning and management of the water resources in general and of the Andean watersheds in particular. This study compares Markov chain- (MC and Bayesian network- (BN based models in drought forecasting using a recently developed drought index with respect to their capability to characterize different drought severity states. The copula functions were used to solve the BNs and the ranked probability skill score (RPSS to evaluate the performance of the models. Monthly rainfall and streamflow data of the Chulco River basin, located in Southern Ecuador, were used to assess the performance of both approaches. Global evaluation results revealed that the MC-based models predict better wet and dry periods, and BN-based models generate slightly more accurately forecasts of the most severe droughts. However, evaluation of monthly results reveals that, for each month of the hydrological year, either the MC- or BN-based model provides better forecasts. The presented approach could be of assistance to water managers to ensure that timely decision-making on drought response is undertaken.

  5. Upper Cretaceous to Holocene magmatism and evidence for transient Miocene shallowing of the Andean subduction zone under the northern Neuquén Basin

    Science.gov (United States)

    Kay, Suzanne M.; Burns, W. Matthew; Copeland, Peter; Mancilla, Oscar

    2006-01-01

    Evidence for a Miocene period of transient shallow subduction under the Neuquén Basin in the Andean backarc, and an intermittent Upper Cretaceous to Holocene frontal arc with a relatively stable magma source and arc-to-trench geometry comes from new 40Ar/39Ar, major- and trace-element, and Sr, Pb, and Nd isotopic data on magmatic rocks from a transect at ∼36°–38°S. Older frontal arc magmas include early Paleogene volcanic rocks erupted after a strong Upper Cretaceous contractional deformation and mid-Eocene lavas erupted from arc centers displaced slightly to the east. Following a gap of some 15 m.y., ca. 26–20 Ma mafic to acidic arc-like magmas erupted in the extensional Cura Mallín intra-arc basin, and alkali olivine basalts with intraplate signatures erupted across the backarc. A major change followed as ca. 20–15 Ma basaltic andesite–dacitic magmas with weak arc signatures and 11.7 Ma Cerro Negro andesites with stronger arc signatures erupted in the near to middle backarc. They were followed by ca. 7.2–4.8 Ma high-K basaltic to dacitic hornblende-bearing magmas with arc-like high field strength element depletion that erupted in the Sierra de Chachahuén, some 500 km east of the trench. The chemistry of these Miocene rocks along with the regional deformational pattern support a transient period of shallow subduction that began at ca. 20 Ma and climaxed near 5 Ma. The subsequent widespread eruption of Pliocene to Pleistocene alkaline magmas with an intraplate chemistry in the Payenia large igneous province signaled a thickening mantle wedge above a steepening subduction zone. A pattern of decreasingly arc-like Pliocene to Holocene backarc lavas in the Tromen region culminated with the eruption of a 0.175 ± 0.025 Ma mafic andesite. The northwest-trending Cortaderas lineament, which generally marks the southern limit of Neogene backarc magmatism, is considered to mark the southern boundary of the transient shallow subduction zone.

  6. Andean waterways

    DEFF Research Database (Denmark)

    Rasmussen, Mattias Borg

    Andean Waterways explores the politics of natural resource use in the Peruvian Andes in the context of climate change and neoliberal expansion. It does so through careful ethnographic analysis of the constitution of waterways, illustrating how water becomes entangled in a variety of political...

  7. Oligocene-Miocene deformational and depositional history of the Andean hinterland basin in the northern Altiplano plateau, southern Peru

    Science.gov (United States)

    Perez, Nicholas D.; Horton, Brian K.

    2014-09-01

    Cenozoic basin fill of the northern Altiplano plateau records the tectonic development of the flanking Western Cordillera magmatic arc and Eastern Cordillera fold-thrust belt. The Ayaviri hinterland basin of southern Peru contains a ~2300 m thick succession of fluvial sandstones and overbank siltstones (upper Oligocene Puno Group and lower Miocene lower Tinajani Formation) capped by ~400 m of alluvial fan conglomerates (middle Miocene upper Tinajani Formation). New U-Pb zircon chronostratigraphic constraints from ~30 to 15 Ma yield sediment accumulation rates of 110-660 m/Myr. Newly dated growth strata highlight the genetic role played by thrust displacement in basin evolution. A several phase accumulation history derived from chronostratigraphic, provenance, and structural data reveals Oligocene basin filling by fluvial sand and mud that changes provenance from Western Cordillera Mesozoic-Cenozoic volcanic rocks to Paleozoic-Mesozoic Eastern Cordillera sedimentary rocks driven by deformation along the southwest directed, northeastern basin margin Ayaviri thrust at 28-26 Ma. Continued early Miocene fluvial deposition was sourced solely from the Eastern Cordillera. An abrupt middle Miocene shift to coarse alluvial fan deposition sourced from the Western Cordillera was driven by out-of-sequence deformation along the northeast directed, southwestern basin margin Pasani thrust at 18-16 Ma. This northern Altiplano out-of-sequence deformation was coincident with increased Eastern and Western Cordillera exhumation and thrusting and may be symptomatic of changes in critical wedge dynamics. The overall record of basin sedimentation and syndepositional fold-thrust deformation emphasizes the role of regional shortening in governing crustal thickening and basin evolution in the central Andes during the Oligocene to Miocene.

  8. Regional heat flow patterns in the Western Canadian Sedimentary Basin

    Science.gov (United States)

    Majorowicz, J. A.; Jessop, A. M.

    1981-04-01

    The regional geothermal pattern of the Western Canadian Sedimentary Basin has been studied using available temperature data from wells. Average heat conductivity for various geological formations has been estimated on the basis of net rock studies by Canadian Stratigraphie Services. These data and observations of temperature made in "shut-in holes" in some of the oil pools have been used in heat flow estimations by the Bullard method. The geothermal gradient and heat flow within the basin are exceptionally high in comparison with the other world wide Precambrian platform areas. Especially high geothermal gradient areas are found in the northwestern part of the Prairies Basin in Alberta and British Columbia and most of southeastern and southwestern Saskatchewan. Areas of low gradient are found mainly in the Disturbed Belt of the Foothills, southern and southeastern Alberta, and the Peace River area in British Columbia. Neither the analysis of regional heat conductivity distribution nor the heat generation distribution of the basement rock of the Prairies Basin evaluated on the basis of U, Th and K data after Burwash (1979), explain the observed heat flow patterns of the Prairies Basin. Comparison of heat flow patterns with some of the hydrogeological phenomena suggests the significant influence of fluid flow in the basin formations on geothermal features. Low geothermal gradient areas coincide with water recharge areas and high hydraulic head distribution regions. The phenomenon of upward water movement in the deep strata and downward flow through much of the Cenozoic and Mesozoic strata seems to control the regional heat flow distribution in the basin. The analyses of coal metamorphism in the upper and middle Mesozoic formations of the Foothills Belt and in the central Prairies Basin suggest that the pre-Laramide paleogeothermal heat flow distribution was different from the present one. It is very probable that the Foothills Belt area was characterized by a higher

  9. Assessing groundwater recharge in an Andean closed basin using isotopic characterization and a rainfall-runoff model: Salar del Huasco basin, Chile

    Science.gov (United States)

    Uribe, Javier; Muñoz, José F.; Gironás, Jorge; Oyarzún, Ricardo; Aguirre, Evelyn; Aravena, Ramón

    2015-11-01

    Closed basins are catchments whose drainage networks converge to lakes, salt flats or alluvial plains. Salt flats in the closed basins in arid northern Chile are extremely important ecological niches. The Salar del Huasco, one of these salt flats located in the high plateau (Altiplano), is a Ramsar site located in a national park and is composed of a wetland ecosystem rich in biodiversity. The proper management of the groundwater, which is essential for the wetland function, requires accurate estimates of recharge in the Salar del Huasco basin. This study quantifies the spatio-temporal distribution of the recharge, through combined use of isotopic characterization of the different components of the water cycle and a rainfall-runoff model. The use of both methodologies aids the understanding of hydrological behavior of the basin and enabled estimation of a long-term average recharge of 22 mm/yr (i.e., 15 % of the annual rainfall). Recharge has a high spatial variability, controlled by the geological and hydrometeorological characteristics of the basin, and a high interannual variability, with values ranging from 18 to 26 mm/yr. The isotopic approach allowed not only the definition of the conceptual model used in the hydrological model, but also eliminated the possibility of a hydrogeological connection between the aquifer of the Salar del Huasco basin and the aquifer that feeds the springs of the nearby town of Pica. This potential connection has been an issue of great interest to agriculture and tourism activities in the region.

  10. Modeling of channel patterns in short tidal basins

    NARCIS (Netherlands)

    Marciano, R.; Wang, Z.B.; Hibma, A.; De Vriend, H.J.; Defina, A.

    2005-01-01

    We model branching channel patterns in short tidal basins with two methods. A theoretical stability analysis leads to a relationship between the number of channels and physical parameters of the tidal system. The analysis reveals that width and spacing of the channels should decrease as the slope of

  11. The Genetic History of Peruvian Quechua-Lamistas and Chankas: Uniparental DNA Patterns among Autochthonous Amazonian and Andean Populations.

    Science.gov (United States)

    Sandoval, José R; Lacerda, Daniela R; Acosta, Oscar; Jota, Marilza S; Robles-Ruiz, Paulo; Salazar-Granara, Alberto; Vieira, Pedro Paulo R; Paz-Y-Miño, César; Fujita, Ricardo; Santos, Fabricio R

    2016-03-01

    This study focuses on the genetic history of the Quechua-Lamistas, inhabitants of the Lamas Province in the San Martin Department, Peru, who speak their own distinct variety of the Quechua family of languages. It has been suggested that different pre-Columbian ethnic groups from the Peruvian Amazonia, like the Motilones or "shaven heads", assimilated the Quechua language and then formed the current native population of Lamas. However, many Quechua-Lamistas claim to be direct descendants of the Chankas, a famous pre-Columbian indigenous group that escaped from Inca rule in the Andes. To investigate the Quechua-Lamistas and Chankas' ancestries, we compared uniparental genetic profiles (17 STRs of Q-M3 Y-chromosome and mtDNA complete control region haplotypes) among autochthonous Amazonian and Andean populations from Peru, Bolivia and Ecuador. The phylogeographic and population genetic analyses indicate a fairly heterogeneous ancestry for the Quechua-Lamistas, while they are closely related to their neighbours who speak Amazonian languages, presenting no direct relationships with populations from the region where the ancient Chankas lived. On the other hand, the genetic profiles of self-identified Chanka descendants living in Andahuaylas (located in the Apurimac Department, Peru, in the Central Andes) were closely related to those living in Huancavelica and the assumed Chanka Confederation area before the Inca expansion. PMID:26879156

  12. The role of the hydrological cycle on the temporal patterns of macroinvertebrate assemblages in an Andean foothill stream in Colombia

    Directory of Open Access Journals (Sweden)

    María I. Ríos-Pulgarín

    2016-03-01

    Full Text Available The seasonal and interannual changes in the structure, composition and functional feeding groups of the macroinvertebrate assemblage of the Guarinó River, a torrential system located in the Colombian Andean foothills, were examined in relation to the physical and chemical environmental changes associated with the hydrological cycle and the El Niño-Niña/Southern Oscillation (ENSO between 2007 and 2010. Benthic samples were collected at three sites in the lower sections of the river. A total of 127 taxa were collected in the study, with the total taxonomic richness per site ranging from 82 to 96 taxa and benthos density averaging 5.41 ind. m-2. The density showed a tendency to decrease in periods of maximum river level and flow, particularly during La Niña phenomena, and to increase in dry periods, especially in the third year (2009-2010 during El Niño phenomena. The presence and abundance of taxa, functional feeding groups and life habits were regulated by environmental parameters associated with hydrological variability, derived of ENSO phenomena, especially flow rate values. The assemblage showed high taxonomic and functional diversity, which is characteristic of ecosystems affected by recurrent hydrological disturbances, exhibiting differentiated responses based on adaptive strategies against the local hydrologic regime that allow fast recovery under conditions like ENSO phenomena. Such responses include composition changes according to adaptations to different hydrological scenarios, the predominance of generalist trophic guilds and taxa with plasticity in their habits and range of environmental tolerance.

  13. Trans-Andean Ancistrus (Siluriformes: Loricariidae).

    Science.gov (United States)

    Taphorn, Donald C; Armbruster, Jonathan W; Villa-Navarro, Francisco; Ray, C Keith

    2013-01-01

    We review the trans-Andean species of Ancistrus from Panama, Colombia and Venezuela. Based on analyses of meristic, morphometric and pigmentation pattern data of preserved specimens, eight of sixteen species reported from this region are considered valid and two new species are described. Here we review Ancistrus chagresi Eigenmann & Eigenmann 1889 from both slopes of central Panama; A. centrolepis Regan 1913 from Pacific slopes of eastern Panama and western Colombia; Ancistrus caucanus Fowler 1943, from the Magdalena River drainage in northern Colombia; Ancistrus martini Schultz 1944, from the Lake Maracaibo Basin of Venezuela and Colombia. Ancistrus galani Pérez & Viloria 1994, from a cave in the Lake Maracaibo Basin of Venezuela is considered valid but was not examined. Ancistrus tolima new species is described from the upper Magdalena River drainage and Ancistrus vericaucanus new species is described from the upper Cauca River drainage. Ancistrus gymnorhynchus Kner 1854 and A. falconensis Taphorn, Armbruster & Rodriguez-O. 2010 were treated previously. One specimen of A. clementinae Rendahl 1937 from the Pacific coast of Ecuador was examined, it is considered a valid species. A key for identification and geographical ranges are provided. PMID:26287090

  14. Assessing the effect of natural controls and land use change on sediment yield in a major Andean River: the Magdalena drainage basin, Colombia.

    Science.gov (United States)

    Restrepo, Juan Darío; Syvitski, James P M

    2006-03-01

    The Magdalena River, a major fluvial system draining most of the Colombian Andes, is a world-class river, in the top 10 in terms of sediment load (approximately 150 MT/yr). In this study, we explore the major natural factors and anthropogenic influences behind the patterns in sediment yield on the Magdalena basin and reconstruct the spatial and temporal pattern of deforestation and agricultural intensification across the basin to test the relationships between land use change and trends in sediment yield. Our results show that sediment yield for the whole Magdalena catchment can be explained by natural variables, including runoff and maximum water discharge. These two estimators explain 58% of variance in sediment yield. Temporal analyses of sediment discharges and land use show that the extent of erosion within the catchment has increased over the last 10 to 20 years. Many anthropogenic influences, including a forest decrease by 40% in a 20-year period, an agriculture and pasture increase by 65%, poor soil conservation and mining practices, and increasing rates of urbanization, may have accounted for the overall increasing trends in sediment yield on a regional scale. PMID:16722251

  15. Detrital Zircon Provenance Record of Pre-Andean to Modern Tectonics in the Northern Andes: Examples from Peru, Ecuador, and Colombia

    Science.gov (United States)

    George, S. W. M.; Jackson, L. J.; Horton, B. K.

    2015-12-01

    Detrital zircon U-Pb age distributions from modern rivers and Mesozoic-Cenozoic basin fill in the northern Andes provide insights into pre-Andean, Andean, and active uplift and exhumation of distinctive sediment source regions. Diagnostic age signatures enable straightforward discrimination of competing sediment sources within the Andean magmatic arc (Western Cordillera-Central Cordillera), retroarc fold-thrust belt (Eastern Cordillera-Subandean Zone), and Amazonian craton (composed of several basement provinces). More complex, however, are the mid/late Cenozoic provenance records generated by recycling of basin fill originally deposited during early/mid Mesozoic extension, late Mesozoic thermal subsidence, and early Cenozoic shortening. Although subject to time-transgressive trends, regionally significant provenance patterns in Peru, Ecuador, and Colombia reveal: (1) Triassic-Jurassic growth of extensional subbasins fed by local block uplifts (with commonly unimodal 300­-150 Ma age peaks); (2) Cretaceous deposition in an extensive postrift setting fed by principally cratonic sources (with common 1800-900 Ma ages); and (3) Cenozoic growth of a broad flexural basin fed initially fed by magmatic-arc rocks (100-0 Ma), then later dominance by thrust-belt sedimentary rocks with progressively greater degrees of basin recycling (yielding diverse and variable age populations from the aforementioned source regions). U-Pb results from modern rivers and smaller subbasins prove useful in evaluating source-to-sink relationships, downstream mixing relationships, hinterland-foreland basin connectivity, paleodrainage integration, and tectonic/paleotopographic reconstructions. Most but not all of the elevated intermontane basins in the modern hinterland of the northern Andes contain provenance records consistent with genesis in a broader foreland basin developed at low elevation. Downstream variations within modern axial rivers and Cenozoic axial basins inform predictive models of

  16. Sedimentary thickness and velocity in the northeast boundary of the Parana Basin with Andean earthquakes and local events; Espessura e velocidade das camadas sedimentares na borda nordeste da Bacia do Parana utilizando telessismos da regiao andina e sismos locais

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Josimar A.; Souza, Luiz M. [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Geofisica; Assumpcao, Marcelo S. [Universidade de Sao Paulo (USP), SP (Brazil)

    2008-07-01

    Deep Andean earthquakes are a suitable source of high-frequency P-waves (with good signal to noise ratio up to {approx} 10 Hz) that can be used to obtain high-resolution receiver functions at stations in intra-cratonic basins in Brazil. Receiver functions (Gaussian width 20) at five stations in the Bebedouro seismic area (NE Parana Basin) were calculated using the time domain deconvolution of Ligorria and Ammon (1999). Inter-station Rayleigh wave phase velocities were measured using local earthquakes. Joint inversion of receiver functions and Rayleigh phase velocities provided reasonably well constrained S-wave velocity profiles. Shallow seismic refraction surveys were used to fix the velocities of the surface layers during the inversion. The area is characterized by a thin surface layer of sandstones ({approx}60 m), followed by a {approx}500 m thick basalt layer. Beneath the basalts, low-velocity layers define another sedimentary sequence. These features are consistent with the expected values based on well data at regional distances and confirm the usefulness of high-frequency receiver functions to study sedimentary basins. (author)

  17. The Jurassic-Cretaceous Boundary (Tithonian - Hauterivian) in the Andean Basin of Central Chile: Ammonites, Bio- and Sequence Stratigraphy and Palaeobiogeography

    OpenAIRE

    Salazar Soto, Christian Andrés

    2012-01-01

    Five sections of the Baños del Flaco and Lo Valdés formations in the High Andean Cordillera of Central Chile have been analyzed with regard to sediment, bio- and sequence stratigraphy, ammonite assemblages and palaeobiogeography, in order to reveal the age and depositional facies of the sediment sequence, and to evaluate the age and important bioevents across the Jurassic-Cretaceous boundary. The Baños del Flaco Formation was investigated at Rio Tinguiririca and in the Rio Maitenes valley,...

  18. Influence of Andean Plateau Rise on South American Climate Dynamics

    Science.gov (United States)

    Insel, N.; Poulsen, C. J.; Ehlers, T. A.

    2008-12-01

    Large mountain ranges exhibit a first-order control on climate. In South America, the modern Andes act as a barrier to atmospheric flow and control regional wind and precipitation patterns. However, it is unclear how climate may have changed over time as Andean topography developed. We present results from a regional general circulation model (RegCM3) to evaluate dynamical and physical atmospheric changes associated with variations in Andean plateau height during the Cenozoic. A series of five experiments were conducted with plateau topography systematically varying between 0 and 100% of the modern. Experiments were performed over a continental-scale domain with 60km horizontal resolution using the MIT-Emanuel convection scheme. Land surface characteristics, sea-surface temperatures and atmospheric boundary conditions were specified from modern NCEP reanalysis data. Model results show that large-scale upper-level (200 mbar) circulation characteristics are only weakly affected by the removal of the Andes with a slight weakening and eastward shift of the high pressure system over Bolivia. However, low-level (800 mbar) wind patterns change significantly and have a direct effect on precipitation in South America. The following features can be observed as the Andean topography decreases: (1) The dominant wind direction in the central Andes reverses with prevailing winds sourced from the Pacific Ocean. The Westerlies are characterized by low moisture content due to the presence of the cold Humboldt current along the west coast of South America. (2) A reduction in the surface pressure gradient between the Andes and the Amazon Basin reduces convergence over the plateau and suppresses the South American low level jet, reducing the southward moisture flux along the eastern flanks of the Andes that is the primary source for precipitation in the Chaco region. These changes lead to declines in precipitation over the Andes and decreased latent heat release. This results in a

  19. Ecological niche models and patterns of richness and endemism of the southern Andean genus Eurymetopum (Coleoptera, Cleridae) Modelos de nicho ecológico y patrones de riqueza y endemismo del género andino austral Eurymetopum (Coleoptera, Cleridae)

    OpenAIRE

    Tania Escalante; Miguel Linaje; Patricia Illoldi-Rangel; Miguel Rivas; Patricia Estrada; Francisca Neira; Morrone, Juan J.

    2009-01-01

    Eurymetopum is an Andean clerid genus with 22 species. We modeled the ecological niches of 19 species with Maxent and used them as potential distributional maps to identify patterns of richness and endemicity. All modeled species maps were overlapped in a single map in order to determine richness. We performed an optimality analysis with NDM/VNDM in a grid of 1º latitude-longitude in order to identify endemism. We found a highly rich area, located between 32º and 41º south latitude, where the...

  20. Characterization of Reconstructed Basins Using Pattern Spectrum Procedure

    Directory of Open Access Journals (Sweden)

    P. Radhakrishnan

    2005-01-01

    Full Text Available Several classical and Fractal binary shapes, which are akin to geophysical shapes such as basins, lakes, and pore-grain spruce, are analyzed and characterized by employing various mathematical morphological transformations, and methods. By employing rhombus, square and octagon structuring elements, these shapes are decomposed into their skeletal networks and their corresponding skeletal network subsets are dilated to the respective degree by these structuring elements in order to reconstruct the original shapes. Furthermore, to test the reconstruction accuracy, the pattern spectrum procedure is applied and sharpness indices were computed. These shapiness indices were considered as a basis to test the reconstruction accuracy in a quantitative manner. A general trend is observed while characterizing the shape-size complexity of these surface water bodies.

  1. Discussion on marine source rocks thermal evolvement patterns in the Tarim Basin and Sichuan Basin, west China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Taking marine source rocks of lower Paleozoic in the Tarim Basin and Paleozoic ones in the Sichuan Basin as examples, their sedimentation process could be classified into four styles: continuous subsldence with deep sedimentation in early stage, continuous subsidence with deep sedimentation in later stage, that deeply buried-uplift-shallowly buried, and that shallowly buried-uplift-deeply buried.Unlike that in East China, the marine source rocks evolvement patterns did not accord with sedimentation styles one by one in superimposed basins in west China. Taking local geothermal field into account, four types of source rock evolvement patterns were built: that evolved fast in early stage,evolved fast in middle stage, evolved continuously and evolved in multistage. Among them, the 1st pattern contributed little to the present industrial oil pools directly, but paleo-oil reservoirs and gases cracked from crude oils were main exploration targets. Although some gases were found in the 2nd pattern, the scale was not big enough. For the 3rd and 4th patterns, the hydrocarbon potential depended on organic matters maturity in early stage. For relatively low mature rocks, it was possible to generate some oils in later stage; otherwise the main products were gases. Paleo-oil reservoirs remained fairly well in the Sichuan Basin, and most source rocks underwent kerogen-oil-gas processes,which was useful reference to gas exploration in the Tarim Basin.

  2. The Formation, Movement and Evolution Pattern of Jurassic Terrestrial Deposit Basin in Daqingshan Region

    Institute of Scientific and Technical Information of China (English)

    PENG Xiangdong; XU Zhongyuan; LIU Zhenghong

    2001-01-01

    The authors have reconstructed the original shape of Jurassic basin in Daqingshan region and discussed the movement and evolution pattern of the basin. The basin developed between Paleozoic strata sliver and metamorphic rock sliver in late stage of Early Jurassic and extended in latitude direction. The palco - terrene of the basin is higher in north and west than south and east. The boundary of basin is largest in Changhangou stage of Middle Jurassic. After middle Jurassic, the region took place Yenshan movement, and then the basin changed obviously from weakly extending environment of Early and Middle Jurassic to extruding environment of late Jurassic, and the paleoclimate of the basin changed from warmth and wetness to dry. The basin finished the evolution history in the late stage of Late Jurassic with the development of thrust.

  3. Snow instability patterns at the scale of a small basin

    Science.gov (United States)

    Reuter, Benjamin; Richter, Bettina; Schweizer, Jürg

    2016-02-01

    Spatial and temporal variations are inherent characteristics of the alpine snow cover. Spatial heterogeneity is supposed to control the avalanche release probability by either hindering extensive crack propagation or facilitating localized failure initiation. Though a link between spatial snow instability variations and meteorological forcing is anticipated, it has not been quantitatively shown yet. We recorded snow penetration resistance profiles with the snow micropenetrometer at an alpine field site during five field campaigns in Eastern Switzerland. For each of about 150 vertical profiles sampled per day a failure initiation criterion and the critical crack length were calculated. For both criteria we analyzed their spatial structure and predicted snow instability in the basin by external drift kriging. The regression models were based on terrain and snow depth data. Slope aspect was the most prominent driver, but significant covariates varied depending on the situation. Residual autocorrelation ranges were shorter than the ones of the terrain suggesting external influences possibly due to meteorological forcing. To explore the causes of the instability patterns we repeated the geostatistical analysis with snow cover model output as covariate data for one case. The observed variations of snow instability were related to variations in slab layer properties which were caused by preferential deposition of precipitation and differences in energy input at the snow surface during the formation period of the slab layers. Our results suggest that 3-D snow cover modeling allows reproducing some of the snow property variations related to snow instability, but in future work all relevant micrometeorological spatial interactions should be considered.

  4. Use of space, activity patterns, and foraging behavior of red howler monkeys (Alouatta seniculus) in an Andean forest fragment in Colombia.

    Science.gov (United States)

    Palma, Ana Cristina; Vélez, Adriana; Gómez-Posada, Carolina; López, Harrison; Zárate, Diego A; Stevenson, Pablo R

    2011-10-01

    Howler monkeys are among the most studied primates in the Neotropics, however, behavioral studies including estimation of food availability in Andean forests are scarce. During 12 months we studied habitat use, behavior, and feeding ecology of two groups of red howler monkeys (Alouatta seniculus) in an isolated fragment in the Colombian Andes. We used a combination of focal animal and instantaneous sampling. We estimated fruit production (FP) using phenology transects, and calculated young leaf abundance by observing marked trees. The home range area used by each group was 10.5 and 16.7 ha and daily distances traveled were 431 ± 228 and 458 ± 259 m, respectively. We found that both groups spent most of their time resting (62-64%). Resting time did not increase with leaf consumption as expected using a strategy of energy minimization. We did not find a relationship between daily distances traveled and leaf consumption. However, howlers consumed fruits according to their availability, and the production of young leaves did not predict feeding time on this resource. Overall, our results are similar to those found on other forest types. We found that despite limited FP in Andean forests, this did not lead to a higher intake of leaves, longer resting periods, or shorter traveling distances for red howlers. PMID:21710630

  5. Kinematic evolution of Andean fold-thrust structures along the boundary between the Eastern Cordillera and Middle Magdalena Valley basin, Colombia

    Science.gov (United States)

    SáNchez, Javier; Horton, Brian K.; Tesón, Eliseo; Mora, AndréS.; Ketcham, Richard A.; Stockli, Daniel F.

    2012-06-01

    Surface and subsurface data support a kinematic reconstruction of Cenozoic fold-thrust deformation along the Eastern Cordillera-Magdalena Valley transition in Colombia. The La Salina fault (LSF) marks the boundary between west-vergent Eastern Cordillera structures and hinterland deposits of the Middle Magdalena Valley basin. Apatite fission track and (U-Th)/He thermochronological results for the west-directed LSF reveal initial hanging wall exhumation during middle Eocene-early Oligocene (45-30 Ma) shortening, renewed exhumation in the early middle Miocene (18-12 Ma), and accelerated late Miocene-Pliocene (12-3 Ma) exhumation. Vitrinite reflectance data suggest maximum burial of 4-6 km, helping constrain Cenozoic basin architecture. Mapping of the LSF reveals hanging wall Cretaceous-Eocene rocks in a broad anticline-syncline pair with limited faulting and footwall Eocene-Quaternary basin fill in a complex series of tight thrust-related folds. Limited displacement along the westernmost (frontal) thrust suggests that shortening is largely accommodated by east-directed thrusting within a broader triangle zone of a passive-roof duplex (and probable minor strike-slip deformation). In the preferred kinematic restoration, the most recent phase of shortening to transpressional deformation represents out-of-sequence reactivation of the LSF consistent with irregular crosscutting relationships among footwall structures. Earliest exhumation by 45-30 Ma in the Eastern Cordillera fold-thrust belt is correlated with increased sedimentary lithic fragments and high compositional maturity in sandstones of the adjacent Magdalena Valley basin. Exhumation since ˜15 Ma coincided with decreased compositional maturity and elevated accumulation rates for the Real Group. The compositional provenance shifts are attributed to westward advance of fold-thrust deformation into the proximal (eastern) segments of the Magdalena Valley basin.

  6. Modeling Ecohydrological Processes and Spatial Patterns in the Upper Heihe Basin in China

    OpenAIRE

    Bing Gao; Yue Qin; Yuhan Wang; Dawen Yang; Yuanrun Zheng

    2015-01-01

    The Heihe River is the second largest inland basin in China; runoff in the upper reach greatly affects the socio-economic development in the downstream area. The relationship between spatial vegetation patterns and catchment hydrological processes in the upper Heihe basin has remained unclear to date. In this study, a distributed ecohydrological model is developed to simulate the hydrological processes with vegetation dynamics in the upper Heihe basin. The model is validated by hydrological o...

  7. Qochas on Andean highlands

    CERN Document Server

    Sparavigna, Amelia Carolina

    2011-01-01

    On the Andean highlands, the "qochas" are lakes or ponds of natural or artificial origin. An ancient agricultural technique is based on their use. Linked together by a network of canals, qochas form a system of water and soil management, alternately used for crops or pasture. The concave structure of qochas controls the strong evaporation produced by solar radiation and wind blowing. Qochas can be observed in the satellite imagery of Google Maps.

  8. Clay Mineral Distribution Patterns of Tertiary Continental Oil-bearing Basins in China

    Institute of Scientific and Technical Information of China (English)

    Zhao Xingyuan

    1996-01-01

    @@ Induction This paper studies the clay mineral distribution patterns of Tertiary continental oil-bearing basins in China. More than 9 000 shale samples from Paleogene (E) to Neogene (N) Series distributed in Bohai Gulf, Subei, Jianghan,Nanxiang, Zhoukou, Sanshui, Beibu Bay, East China Sea,Hetao, Juiquan, Qaidam and Tarim basins, and so on.

  9. Forest landscape patterns dynamics of Yihe—Luohe river basin

    Institute of Scientific and Technical Information of China (English)

    DINGShengyan; SHANGFude; QIANLexiang; CAOXinxiang; LIShuang

    2003-01-01

    Based on the information from forest resources distribution maps of Luoning County of 1983 and 1999,six indices were used to analyze spatial patterns and dynamics of forest landscapes of the typical region in the middle of the Yihe-Luohe river basin.These indices include patch number,mean patch area,fragment index,patdch extension index,etc,The results showed that;(1) There was a rapid increase in the number of patch and total area from 1983 to 1999 in the study area,The fragment degree became very high.(2) The area of all the forest patch types had witnessed great changes,The fractal degree of each forest patch type became big from 1983 to 1999 ,The mean extension index of Robinia pseudoacacia forest ,non- forest shrub forest ,sparse forest ,and Quercus species forest in creased rapidly,but that of economic forest became zero ,The fractal dimension each showed that forest coverage has been promoted.(3)The changes of landscape patterns were different in different geomprhic regions.From 1983 to 1999 the vegetation cover area,the gross number and the density of patch,diversity and evenness of landscape were all reduced greatly in gullies and ravines,but the maximum area and the mean area of patch types were increased ,In hilly region,both the forest cover area and the number of patch increased from 1983 to 1999,but the mean area of patch was reduced greatly,In mountain region,even though the area under forest canopy reduced from 1983 to 1999 ,the patch number was increased greatly,the mean area of all patch types was reduced ,the extension index,diversity index and evenness index of landscape were all increased.Furthermore,because of different types of land use,human activtiy and terratin ,the vegetation changes on northern and southern mountain slopes were different.According to these analyses,the main driving forces,such as the policies of management,market economy,influence of human activities etc.are brought out.

  10. Andean region study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-10-01

    New opportunities for climate change mitigation arising from a higher energy integration among Andean Pact nations were analysed within the framework of the UNEP/GEF Project. Apart from the search for regional mitigation actions, the study was mainly aimed at detecting methodological problems which arise when passing from a strictly national view to the co-ordination of regional actions to deal with climate change. In accordance with the available resources and data, and in view of the mainly methodological nature of the project, it was decided to analyse the opportunities to delve into the energy integration of the Region as regards electricity and natural gas industries and their eventual impact on the emission of greenhouse gases. Although possibilities of setting up electricity and natural gas markets are real, their impacts on GHG emission from the energy system would not prove substantially higher than those which the nations could achieve through the use of their own energy resources, in view that the Andean systems are competitive rather than complementary. More in-depth studies and detail information will be required - unavailable for the present study - to be able to properly evaluate all benefits associated with higher energy integration. Nevertheless, the supply of natural gas to Ecuador seems to be the alternative with the highest impact on GHG emission. If we were to analyse the supply and final consumption of energy jointly, we would most certainly detect additional mitigation options resulting from higher co-operation and co-ordination in the energy field. (EHS)

  11. Typical land use pattern in basin - part of the Ziarska kotlina Basin; 1 : 25 000

    International Nuclear Information System (INIS)

    The Ziarska kotlina Basin is one of intensively used areas. Industrial production has distinctly changed the way of land use in this territory. The 'Zavod SNP a. s.' in Ziar nad Hronom producing aluminium is the dominant socio-economic element here. In 1995 the plant was modernised. The stress factors include the largest industrial waste dumping sites in Slovakia (sludge beds and cinder fields). The forest in the Ziarska kotlina Basin contains two main wood species, the durmast oak and beech. The territory stretches over four vegetation zones: the oak, oak-beech, beech-oak, and beech. Nine units in this basin represent the grassy and herbaceous vegetation. The natural and semi-natural meadows are of high ecological value for the local landscape. Cultivated floodplain meadows spread on the alluvium of the Hron river but they also frequently occur next to the brooks flowing in the area. Floristic composition of these meadows is comparatively dull. (authors)

  12. Infection patterns of Tylodelphys barilochensis and T. crubensis (Trematoda: Diplostomatidae) metacercariae in Galaxias maculatus (Osmeriformes: Galaxiidae) from two Patagonian lakes and observations on their geographical distribution in the southern Andean region, Argentina.

    Science.gov (United States)

    Flores, Verónica; Liliana, Semenas

    2002-12-01

    In the Patagonian Andean region, 2 species of diplostomatids parasitize the brains of Galaxias maculatus. The purpose of this study was to evaluate seasonal variation, spatial variation, and association with host age in the transmission of Tylodelphys barilochensis and T. crubensis in several oligotrophic lakes in Argentinian Patagonia. Fishes were captured monthly in Lake Gutiérrez and bimonthly in Lake Escondido. One summer or autumn sample was also taken in several other Patagonian lakes. Infection parameters were calculated and compared using nonparametric tests. The 2 species co-occurred in most of the sampled lakes, with high values of prevalence and mean intensity. In Lake Gutiérrez and Lake Escondido, the intensity of both diplostomatid species did not show significant differences between sexes and co-varied with host length. All age classes were infected; maximum prevalence values were reached before maximum mean intensity values in the 1-yr age class. A seasonal pattern of prevalence and mean intensity of the 2 parasite species with autumn mean intensity values differing significantly from those of the other seasons was evident only in Lake Gutiérrez. PMID:12537107

  13. Large-scale circulation patterns and related rainfall in the Amazon Basin: a neuronal networks approach

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza, Jhan Carlo [LOCEAN - IPSL (IRD, CNRS, MNHN, UPMC), Paris Cedex 05 (France); Universidad Agraria La Molina UNALM, Lima (Peru); Lengaigne, Matthieu; Janicot, Serge [LOCEAN - IPSL (IRD, CNRS, MNHN, UPMC), Paris Cedex 05 (France); Ronchail, Josyane [LOCEAN - IPSL (IRD, CNRS, MNHN, UPMC), Paris Cedex 05 (France); Universite Paris 7, Paris (France)

    2012-01-15

    This study describes the main circulation patterns (CP) in the Amazonian Basin over the 1975-2002 period and their relationship with rainfall variability. CPs in the Amazonian Basin have been computed for each season from the ERA-40 daily 850 hPa winds using an approach combining artificial neural network (Self Organizing Maps) and Hierarchical Ascendant Classification. A 6 to 8 cluster solutions (depending on the season considered) is shown to yield an integrated view of the complex regional circulation variability. For austral fall, winter and spring the temporal evolution between the different CPs shows a clear tendency to describe a cycle, with southern wind anomalies and their convergence with the trade winds progressing northward from the La Plata Basin to the Amazon Basin. This sequence is strongly related to eastward moving extra tropical perturbations and their incursion toward low latitude that modulate the geopotential and winds over South America and its adjoining oceans. During Austral summer, CPs are less spatially and temporally organized compared to other seasons, principally due to weaker extra tropical perturbations and more frequent shallow low situations. Each of these CPs is shown to be associated with coherent northward moving regional rainfall patterns (both in in situ data and ERA-40 reanalysis) and convective activity. However, our results reveals that precipitation variability is better reproduced by ERA-40 in the southern part of the Amazonian Basin than in the northern part, where rainfall variability is likely to be more constrained by local and subdaily processes (e.g. squall lines) that could be misrepresented in the reanalysis dataset. This analysis clearly illustrates the existing connections between the southern and northern part of the Amazonian Basin in terms of regional circulation/rainfall patterns. The identification of these CPs provide useful information to understand local rainfall variability and could hence be used to

  14. Large-scale circulation patterns and related rainfall in the Amazon Basin: a neuronal networks approach

    Science.gov (United States)

    Espinoza, Jhan Carlo; Lengaigne, Matthieu; Ronchail, Josyane; Janicot, Serge

    2012-01-01

    This study describes the main circulation patterns (CP) in the Amazonian Basin over the 1975-2002 period and their relationship with rainfall variability. CPs in the Amazonian Basin have been computed for each season from the ERA-40 daily 850 hPa winds using an approach combining artificial neural network (Self Organizing Maps) and Hierarchical Ascendant Classification. A 6 to 8 cluster solutions (depending on the season considered) is shown to yield an integrated view of the complex regional circulation variability. For austral fall, winter and spring the temporal evolution between the different CPs shows a clear tendency to describe a cycle, with southern wind anomalies and their convergence with the trade winds progressing northward from the La Plata Basin to the Amazon Basin. This sequence is strongly related to eastward moving extra tropical perturbations and their incursion toward low latitude that modulate the geopotential and winds over South America and its adjoining oceans. During Austral summer, CPs are less spatially and temporally organized compared to other seasons, principally due to weaker extra tropical perturbations and more frequent shallow low situations. Each of these CPs is shown to be associated with coherent northward moving regional rainfall patterns (both in in situ data and ERA-40 reanalysis) and convective activity. However, our results reveals that precipitation variability is better reproduced by ERA-40 in the southern part of the Amazonian Basin than in the northern part, where rainfall variability is likely to be more constrained by local and subdaily processes (e.g. squall lines) that could be misrepresented in the reanalysis dataset. This analysis clearly illustrates the existing connections between the southern and northern part of the Amazonian Basin in terms of regional circulation/rainfall patterns. The identification of these CPs provide useful information to understand local rainfall variability and could hence be used to

  15. Comparison of Irrigation Performance Based on the Basin, Crop Pattern, and Scheme Sizes Using External Indicators

    OpenAIRE

    Merdun, Hasan

    2004-01-01

    A comparative assessment allows screening of irrigation systems based on the key issues relative to performance and indicates where improvements should be made, such as in type of management, infrastructure, crop pattern and intensity, and system size. The objective of this study was to assess the performance of 239 irrigation schemes (57 DSI-operated and 182 transferred to Irrigation Associations) based on the basin, crop pattern, and scheme sizes using 6 external indicators for 2001. The ba...

  16. Modeling Ecohydrological Processes and Spatial Patterns in the Upper Heihe Basin in China

    Directory of Open Access Journals (Sweden)

    Bing Gao

    2015-12-01

    Full Text Available The Heihe River is the second largest inland basin in China; runoff in the upper reach greatly affects the socio-economic development in the downstream area. The relationship between spatial vegetation patterns and catchment hydrological processes in the upper Heihe basin has remained unclear to date. In this study, a distributed ecohydrological model is developed to simulate the hydrological processes with vegetation dynamics in the upper Heihe basin. The model is validated by hydrological observations at three locations and soil moisture observations at a watershed scale. Based on the simulated results, the basin water balance characteristics and their relationship with the vegetation patterns are analyzed. The mean annual precipitation and runoff increase with the elevation in a similar pattern. Spatial patterns of the actual evapotranspiration is mainly controlled by the precipitation and air temperature. At the same time, vegetation distribution enhances the spatial variability of the actual evapotranspiration. The highest actual evapotranspiration is around elevations of 3000–3600 m, where shrub and alpine meadow are the two dominant vegetation types. The results show the mutual interaction between vegetation dynamics and hydrological processes. Alpine sparse vegetation and alpine meadow dominate the high-altitude regions, which contribute most to the river runoff, and forests and shrub contribute relatively small amounts of water yield.

  17. Sandbox Modeling of the Fault-increment Pattern in Extensional Basins

    Institute of Scientific and Technical Information of China (English)

    Geng Changbo; Tong Hengmao; He Yudan; Wei Chunguang

    2007-01-01

    Three series of sandbox modeling experiments were performed to study the fault-increment pattern in extensional basins.Experimental results showed that the tectonic action mode of boundaries and the shape of major boundary faults control the formation and evolution of faults in extensional basins.In the process of extensional deformation,the increase in the number and length of faults was episodic,and every 'episode' experienced three periods,strain-accumulation period,quick fault-increment period and strain-adjustment period.The more complex the shape of the boundary fault,the higher the strain increment each 'episode' experienced.Different extensional modes resulted in different fault-increment patterns.The horizontal detachment extensional mode has the 'linear' style of fault-increment pattern,while the extensional mode controlled by a listric fault has the 'stepwise' style of fault-increment pattern,and the extensional mode controlled by a ramp-flat boundary fault has the 'stepwise-linear' style of fault-increment pattern.These fault-increment patterns given above could provide a theoretical method of fault interpretation and fracture prediction in extensional basins.

  18. Facies pattern of the middle Permian Barren Measures Formation, Jharia basin, India: The sedimentary response to basin tectonics

    Indian Academy of Sciences (India)

    Prabir Dasgupta

    2005-06-01

    In the Lower Gondwana succession of the Jharia basin of eastern India, the Barren Measures Formation is characterized by the cyclic disposition of fine-grained lacustrine deposits and relatively coarse-grained fluvial deposits. The cyclic variation in the rate of coarse clastic input is attributed to the sedimentary response to basin tectonics. The sandstone–shale alternations of the Barren Measures succession can be correlated with the tectonic cyclothems developed on the hangingwall dip-slope and adjoining trough in a continental half-graben setting. Enhancement of the gradient of the hangingwall dip-slope during reactivation of the basin margin faults led to progradation of the existing fluvial system towards the half-graben trough and deposition of the coarser clastics on the fine-grained lacustrine deposits of the trough. Peneplanation of the hangingwall slope and slow increase in the lake level caused lacustrine transgression and retrogration of the fluvial system on the hangingwall block. The fluvial sediments were onlapped by the fine-grained lacustrine deposits. Episodic rejuvenation of the basin margin faults thus caused development of tectonic cyclothem on the hangingwall block. The paleocurrent pattern indicates that a persistent northward paleoslope was maintained during Barren Measures sedimentation. The inferred depositional settings were much more extensive than the present limit of the outcrop. The faults, presently defining the northern limit of the Barren Measures Formation, were possibly emplaced after Barren Measures sedimentation. The final movement along these fault planes caused preservation of the downthrown hangingwall block and the Barren Measures sediments on the footwall block were eroded during subsequent denudation. The Southern Boundary Fault came into existence after the deposition of the Barren Measures sediments.

  19. Modeling spatial patterns of terrestrial water cycle components for large river basins

    Science.gov (United States)

    Motovilov, Yuri; Popova, Natalia

    2016-04-01

    The ECOMAG model (ECOlogical Model for Applied Geophysics) was applied for simulating spatial patterns of the terrestrial water cycle components (soil moisture, snow water equivalent, specific runoff) for the Volga River basin (area 1 380 000 km2) and the Lena River basin (area 2 488 000 km2). The simulated patterns were evaluated through their comparison against the corresponding patterns obtained from multi-year observation data. The semi-distributed hydrological model ECOMAG utilizes semi-distributed approach, where a major river basin is covered with a grid of elementary watersheds taking into account structure of river network, topography, soil and land cover characteristics. For each elementary watershed a model of land hydrological cycle with lumped parameters (water infiltration into unfrozen and frozen soil, evapotranspiration, thermal and water regime of soil, overland, subsurface and channel flow) is described by a system of ordinary differential equations. Most of them are obtained by integrating the basic equations of detailed physically based models over space. Most of the model land surface parameters are physically meaningful and can be assigned from global data sets. Some key-parameters are calibrated against streamflow measurements and monitoring of the internal basin variables (patterns of snow characteristics, soil moisture, soil frost depth, etc.). The methodology of the spatial calibration parameters and appropriate criteria of the model performance are considered. Minimal and maximal sizes of elementary watersheds for considered river basins are estimated on the basis of numerical experiments with using such criteria. Acknowledgements. The work was financially supported by the Russian Foundation for Basic Research (Grant 16-05-00864)

  20. Basin patterns of upper ocean warming for 1993-2009

    Science.gov (United States)

    Chang, You-Soon

    2014-06-01

    A previous study (Lyman et al., Nature 465:334-337, 2010) showed a robust warming signal of the global upper ocean (0-700 m). They examined several sources of uncertainty that contribute to differences among heat content estimations. However, their focus was limited to globally averaged estimation. This study presents the spatial pattern of the global heat content change based on observed gridded datasets (Levitus et al., Geophys Res Lett 36:L07608, 2009). The western Pacific, Atlantic, and Indian Oceans showed significant warming trends, whereas eastern Pacific and some areas of the Gulf Stream experienced negative trends during 1993-2009. Steady warming trend was obtained from the first EOF mode when El Nino and Southern Oscillation (ENSO)-related signals were removed. This result implies that the rapid increase in heat content of the upper ocean around 2000-2005 is not related to a sampling transition from XBT to Argo observations but is associated with a natural variability dominated by strong ENSO-related signals.

  1. Pattern and Landscape Metrics: Tools for Basin Comparison and Insight in Hydrological Processes

    Science.gov (United States)

    van Nieuwenhuyse, Bartel; Wyseure, Guido

    2010-05-01

    The control heterogeneous landscapes exert on the hydrological functioning of a basin necessitates a profounder understanding of their complex interaction in order to allow appropriate extrapolation to ungauged basins. Spatial structures, such as the mosaic-like pattern of water contributing and accepting areas and the network of flow paths, have been identified as a significant control on the surface hydrology of semi-arid areas and as a valuable means to classify catchments. An insightful analysis of how patterns act on processes forces itself therefore to the fore. To this end, a virtual model was developed combining a hydrological surface model with varying artificial landscapes. The former worked with a distributed grid of model cells. A network of converging flow paths linking the cells was built according to Mandelbrot's fractal squig. Fixed model parameters for a hydrological sink and source class were distributed over the model cells following five different mapping algorithms which resulted in spatial patterns ranging from the completely random to the highly clustered. Green-Ampt infiltration governed the vertical component of the hydrological model and a kinematic wave equation the lateral routing. The resulting basin response in the form of an outlet hydrograph for a single rainfall event was related to spatial characteristics of the structural landscape pattern. The latter quantified in 23 landscape metrics drawn from both ecology and hydrology. Results of statistical analyses show that patterns with a random distribution of sinks and sources have, ceteris paribus, a much smaller variability in their response than patterns organised in distinct patches. Random patterns can therefore be seen as a homogeneous group in which the particular spatial organisation can be neglected when modelling, while more clustered patterns do exhibit an important control on the basin response depending on the connectivity of the pattern, driven by the specific location in

  2. Two new cis-Andean species of the South American catfish genus Megalonema allied to trans-Andean Megalonema xanthum, with description of a new subgenus (Siluriformes: Pimelodidae)

    OpenAIRE

    Lundberg, John G.; Dahdul, Wasila M.

    2008-01-01

    A revised diagnosis of the pimelodid catfish genus Megalonema is given based on synapomorphic features of the Weberian complex and gas bladder. Megalonema xanthum from the Magdalena River is redescribed. Two new cis-Andean species of Megalonema are described, M. amaxanthum n. sp. from the Amazon River basin, and M. orixanthum n. sp. from the Orinoco River basin. These three species are differentially diagnosed by shape and size of the supraoccipital posterior process, adipose-fin shape, verte...

  3. The Studies of Regional Water Circulation Patterns in the Yerqiang River Basin

    Institute of Scientific and Technical Information of China (English)

    REN Jiaguo; WU Qianqian; ZHENG Xilai; XU Mo

    2006-01-01

    Based on the characteristic of ‘one river one oasis' in the arid areas, the Yerqiang River Basin, which is the largest irrigated area of Xinjiang, is taken as an example in this paper, and the regional water circulation pattern is investigated through the analysis of 60 groups of isotope data in the basin. From the phreatic evaporation data analysis of different soils, we study the law of phreatic evaporation, complete the research of the main consumption path of the groundwater,and improve the assessment precision of water resources. The transformation mount of regional water resources are predicted by calculation, which provides a scientific basis for water resources assessment and allocation in arid regions, and offers a new method for the study of regional water circulation patterns.

  4. Territorial pattern and classification of soils of Kryvyi Rih Iron-Ore Basin

    OpenAIRE

    О. О. Dolina; О. М. Smetana

    2014-01-01

    The authors developed the classification of soils and adapted it to the conditions of Krivyi Rih industrial region. It became the basis for determining the degree of soil cover transformation in the iron-ore basin under technogenesis. The classification represents the system of hierarchical objects of different taxonomic levels. It allows determination of relationships between objects and their properties. Researched patterns of soil cover structures’ distribution were the basis for the relev...

  5. Plio-Quaternary kinematic development and paleostress pattern of the Edremit Basin, western Turkey

    Science.gov (United States)

    Gürer, Ömer Feyzi; Sangu, Ercan; Özburan, Muzaffer; Gürbüz, Alper; Gürer, Aysan; Sinir, Hasan

    2016-06-01

    The Edremit Basin and Kazdağ High are the most prominent morphological features of the Biga Peninsula in northwest Anatolia. There is still no consensus on the formation of Edremit Basin and debates are on whether the basin evolved through a normal, a right-lateral or a left-lateral strike-slip faulting. In this study, the geometric, structural and kinematic characteristics of the Edremit Basin are investigated to make an analytical approach to this problem. The structural and kinematic features of the faults in the region are described according to field observations. These fault-slip data derived from the fault planes were analyzed to determine the paleostress pattern of faulting in the region. According to the performed analysis, the southern end of the Biga Peninsula is under the influence of the ENE-WSW-trending faults of the region, such as the Yenice-Gönen, the Edremit, the Pazarköy and the Havran-Balıkesir Fault Zones. The right step-over geometry and related extension caused to the development of the Edremit Basin as a transtensional pull-apart basin between the Havran-Balıkesir Fault Zone and the Edremit Fault Zone. Field observations showed that the Plio-Quaternary faults at the Edremit Gulf and adjacent areas are prominently right-lateral strike-slip faults. Our paleostress analyses suggest a dominant NE-SW extension in the study area, as well as NW-SE direction. This pattern indicates the major effects of the North Anatolian Fault System and the component of Aegean Extensional System in the region. However, our kinematic analysis represents the dominant signature of the North Anatolian Fault System in basin bounding faults. The field observations and kinematic findings of this study are also consistent with the regional GPS, paleomagnetic and seismological data. This study concludes that the North Anatolian Fault System is the prominent structure in the current morphotectonic framework of the Edremit Gulf and adjacent areas.

  6. Pore pressure patterns in Tertiary succession and hydrodynamic implications, Beaufort-Mackenzie Basin, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z.; Issler, D.R.; Osadetz, K.G.; Grasby, S.E. [Natural Resources Canada, Calgary, AB (Canada). Geological Survey of Canada

    2010-03-15

    The fluid pressure regime of the Beaufort-Mackenzie Basin was investigated using mud weight and pore pressure data from 250 exploration wells. Each of the four recognized patterns of pore pressure variation with depth are associated with a specific tectono-stratigraphic domain and indicate the relationship between compaction and tectonics, or other geological factors causing or redistributing the overpressure. In the southwest Beaufort Sea, overpressure likely results from compaction combined with northeast-southwest contractional tectonics. In the north, shale diapirism may produce fracture systems on top of anticlines, causing overpressured fluid to migrate to a shallower depth. Listric faulting prevails in the centre of the Mackenzie Delta, and compaction is the main controlling factor, while lithology and rate of deposition determine the depth of overpressure. Overpressure is mainly confined to Tertiary sedimentary successions, but it may be found in pre-Tertiary strata along the southeast basin margin, possibly in association with Cretaceous gas-generating source rocks. The spatial variation of pore pressure indicates that the upward expulsion of overpressured fluids is the primary driver of basin-scale flow. The pore pressure patterns suggest that regional fault zones can be both a barrier and a preferred flow path network to deep fluid fluxes. Fault zones tend to be regional barrier to lateral flow in an aquifer, but they represent the preferred flow arrangement for episodic vertical fluid migration. 47 ref., 8 figs.

  7. Trade and infrastructure: evidences from the Andean Community

    OpenAIRE

    Rojas, Gina E. Acosta; CALFAT, Germán; Flôres Junior, Renato Galvão

    2005-01-01

    This paper presents evidence on the key role of infrastructure in the Andean Community trade patterns. Three distinct but related gravity models of bilateral trade are used. The first model aims at identifying the importance of the Preferential Trade Agreement and adjacency on intra-regional trade, while also checking the traditional roles of economic size and distance. The second and third models also assess the evolution of the Trade Agreement and the importance of sharing a common border, ...

  8. Ecological niche models and patterns of richness and endemism of the southern Andean genus Eurymetopum (Coleoptera, Cleridae Modelos de nicho ecológico y patrones de riqueza y endemismo del género andino austral Eurymetopum (Coleoptera, Cleridae

    Directory of Open Access Journals (Sweden)

    Tania Escalante

    2009-01-01

    Full Text Available Eurymetopum is an Andean clerid genus with 22 species. We modeled the ecological niches of 19 species with Maxent and used them as potential distributional maps to identify patterns of richness and endemicity. All modeled species maps were overlapped in a single map in order to determine richness. We performed an optimality analysis with NDM/VNDM in a grid of 1º latitude-longitude in order to identify endemism. We found a highly rich area, located between 32º and 41º south latitude, where the richest pixels have 16 species. One area of endemism was identified, located in the Maule and Valdivian Forest biogeographic provinces, which extends also to the Santiago province of the Central Chilean subregion, and contains four endemic species (E. parallelum, E. prasinum, E. proteus, and E. viride, as well as 16 non-endemic species. The sympatry of these phylogenetically unrelated species might indicate ancient vicariance processes, followed by episodes of dispersal. Based on our results, we suggest a close relationship between these provinces, with the Maule representing a complex area.Eurymetopum es un género de cléridos andinos con 22 especies. Modelamos los nichos ecológicos de 19 especies con Maxent y los utilizamos como mapas de distribución potencial para identificar patrones de riqueza y endemismo. Todos los mapas de las especies se superpusieron en un mapa único para determinar la riqueza. Realizamos un análisis de optimalidad con NDM/VNDM en una cuadrícula de 1º de latitud-longitud para identificar el endemismo. Hallamos un área de mayor riqueza, localizada entre los 32º y 41º de latitud sur, donde los pixeles más ricos poseen 16 especies. Se identificó un área de endemismo en las provincias biogeográficas del Maule y el Bosque Valdiviano, la cual se extiende también a la provincia de Santiago de la subregión Chilena Central, y que contiene cuatro especies endémicas (E. parallelum, E. prasinum, E. proteus y E. viride, as

  9. The atmospheric circulation patterns influencing the frequency of spring sand-dust storms in the Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    HongJun Li; XinHua Yang; Yong Zhao; MinZhong Wang; Wen Huo

    2014-01-01

    Using NCEP/NCAR reanalysis data and the sand-storm frequency data from 37 weather stations in the Tarim Basin for the period 1961-2009, the relationship between the frequency of spring sandstorms in the Tarim Basin and the associated atmospheric circu-lation patterns is analyzed in this study. We found significantly negative correlations between sandstorm frequency and the 500-hPa geopotential height over the Paris Basin and midwestern Mongolia, while there were positive correlations over the Ural River region. The rising of the 500-hPa geopotential height in midwestern Mongolia and its falling over the Ural region corre-spond to a weakening of the large-scale wave patterns in the Eurasian region, which directly causes the frequency of the sand-dust storms in the Tarim Basin to decline. Also, the abrupt decline in the spring sandstorm frequency in the Tarim Basin observed in the last half-century is associated with profound changes in the atmospheric circulation in these key regions. At the interannual scale, the strengthened cyclonic atmospheric circulation patterns in the western part of Mongolia and the anticyclonic patterns over the East European plains at 500-hPa geopotential height, are responsible for frequent sandstorm occurrences in the Tarim Basin.

  10. Floristic Characteristics and Biodiversity Patterns in the Baishuijiang River Basin, China

    Science.gov (United States)

    Liu, Bing; Zhao, Wenzhi; Wen, Zijuan; Teng, Jirong; Li, Xiaohong

    2009-07-01

    A case study was conducted on the forest ecosystem in the Baishuijiang River basin of China to reveal the influences of environmental factors and human disturbance on the floristic characteristics and biodiversity patterns. Field surveys of the floristic composition, environmental factors, and disturbance factors were conducted along an elevation gradient, and the relationships between biodiversity pattern and environmental factors were analyzed using CCA (canonical correspondence analysis). The results showed that the floristic composition of higher plants consisted of 197 families, 796 genera, 2165 species, 19 subspecies, 239 varietas, and 12 forma, and it was characterized by the multi-geographic composition and by the transition from tropical to temperate zones. Along an elevation gradient, the variations in α and β diversity were best described by a bimodal curve, and the peak values occurred at middle elevations. The CCA indicated that the elevation had the greatest influence on the biodiversity pattern, followed by the topographic index, slope direction, slope, slope position, slope shape, and vegetation coverage. In addition, human disturbance has greatly impacted the floristic composition and biodiversity patterns, and the biodiversity indices were higher with intermediate disturbance at middle elevations compared to higher and lower disturbances at low and high elevations, respectively. This reflected a disturbance-diversity pattern and thus revealed the obvious importance to maintain the intermediate disturbance for biodiversity conservation.

  11. Winter daily precipitation in La Plata Basin and circulation patterns in Southern South America

    Science.gov (United States)

    Bettolli, Maria Laura; Clorinda Penalba, Olga; Andrés Krieger, Pablo

    2013-04-01

    La Plata Basin is one of the most important agriculture and hydropower producing regions worldwide, where temporal and spatial variability of precipitation have a significant socio-economic impact. The aim of this work is to analyze the dependence of the daily precipitation in the south of La Plata Basin region on the large-scale circulation in Southern South America and its future projection. Daily mean sea level pressure (SLP) fields from NCEP reanalysis 2 were used to represent observed circulation for the period 1979-1999. The analyzed season was austral winter (June-July-August) for the spatial domain from 15°S to 60°S and from 42.5°W to 90°W. The circulation types were obtained by combining the Principal Component Analysis with the k-means Cluster Analysis. Daily precipitation data was used from the gridded datasets of the Claris LPB Project ("A Europe-South America Network for Climate Change Assessment and Impact Studies in La Plata Basin"). Precipitation fields conditioned by the observed surface circulation were analysed and compared. The results indicate that specific daily circulation patterns can be identified as responsible for a significant contribution to precipitation anomalies. The synoptic structures identified in this work can be associated with daily rainfall over the region of study. The classification scheme is effective not only in discriminating dry and rainy days and subregions of La Plata Basin, but also in differentiating between different thresholds of rainfall intensities. In this sense, the findings of this research help to improve our understanding of the relationship between rainfall variability and atmospheric circulation as defined by an objective classification of circulation types.

  12. Trend and uncertainty in spatial-temporal patterns of hydrological droughts in the Amazon basin

    Science.gov (United States)

    Lopes, A. V.; Chiang, J. C. H.; Thompson, S. A.; Dracup, J. A.

    2016-04-01

    Spatial-temporal patterns of hydrological droughts in the Amazon basin are derived from drought indices computed from existing streamflow data. Principal component analysis and Monte Carlo simulations are employed to account for the uncertainty and overcome the limitations of missing data in streamflow records. Results show that northern and southern subbasins differ in drought trends and in patterns of correlation between drought indices and climate anomalies originating from the Pacific (El Niño-Southern Oscillation) and Atlantic (differences in sea surface temperature across the equator) Oceans. A significant trend toward more intense droughts is found in the southern subbasins, which is highly correlated to tropical Atlantic Ocean sea surface temperature anomalies. That drying trend might have distinct causes in each subbasin and can lead to potential intensification of regional impacts.

  13. Mixture model of pottery decorations from Lake Chad Basin archaeological sites reveals ancient segregation patterns.

    Science.gov (United States)

    O'Brien, John D; Lin, Kathryn; MacEachern, Scott

    2016-03-30

    We present a new statistical approach to analysing an extremely common archaeological data type-potsherds-that infers the structure of cultural relationships across a set of excavation units (EUs). This method, applied to data from a set of complex, culturally heterogeneous sites around the Mandara mountains in the Lake Chad Basin, helps elucidate cultural succession through the Neolithic and Iron Age. We show how the approach can be integrated with radiocarbon dates to provide detailed portraits of cultural dynamics and deposition patterns within single EUs. In this context, the analysis supports ancient cultural segregation analogous to historical ethnolinguistic patterning in the region. We conclude with a discussion of the many possible model extensions using other archaeological data types. PMID:27009217

  14. Inter-annual temperature and precipitation variations over the Litani Basin in response to atmospheric circulation patterns

    Science.gov (United States)

    Ramadan, H. H.; Ramamurthy, A. S.; Beighley, R. E.

    2012-05-01

    This study examines the sensitivity of a mid-size basin's temperature and precipitation response to different global and regional climate circulation patterns. The implication of the North Atlantic Oscillation (NAO), El Niño Southern Oscillation (ENSO), Indian Monsoon and ten other teleconnection patterns of the Northern Hemisphere are investigated. A methodology to generate a basin-scale, long-term monthly surface temperature and precipitation time series has been established using different statistical tests. The Litani River Basin is the focus of this study. It is located in Lebanon, east of the Mediterranean Basin, which is known to have diverse geophysical and environmental characteristics. It was selected to explore the influence of the diverse physical and topographical features on its hydroclimatological response to global and regional climate patterns. We also examine the opportunity of conducting related studies in areas with limited long-term measured climate and/or hydrological data. Litani's monthly precipitation and temperature data have been collected and statistically extrapolated using remotely sensed data products from satellites and as well as in situ gauges. Correlations between 13 different teleconnection indices and the basin's precipitation and temperature series are investigated. The study shows that some of the annual and seasonal temperature and precipitation variance can be partially associated with many atmospheric circulation patterns. This would give the opportunity to relate the natural climate variability with the watershed's hydroclimatology performance and thus differentiate it from other anthropogenic induced climate change outcomes.

  15. Volcano-tectonic structures and CO2-degassing patterns in the Laacher See basin, Germany

    Science.gov (United States)

    Goepel, Andreas; Lonschinski, Martin; Viereck, Lothar; Büchel, Georg; Kukowski, Nina

    2015-07-01

    The Laacher See Volcano is the youngest (12,900 year BP) eruption center of the Quarternary East-Eifel Volcanic Field in Germany and has formed Laacher See, the largest volcanic lake in the Eifel area. New bathymetric data of Laacher See were acquired by an echo sounder system and merged with topographic light detection and ranging (LiDAR) data of the Laacher See Volcano area to form an integrated digital elevation model. This model provides detailed morphological information about the volcano basin and results of sediment transport therein. Morphological analysis of Laacher See Volcano indicates a steep inner crater wall (slope up to 30°) which opens to the south. The Laacher See basin is divided into a deep northern and a shallower southern part. The broader lower slopes inclined with up to 25° change to the almost flat central part (maximum water depth of 51 m) with a narrow transition zone. Erosion processes of the crater wall result in deposition of volcaniclastics as large deltas in the lake basin. A large subaqueous slide was identified at the northeastern part of the lake. CO2-degassing vents (wet mofettes) of Laacher See were identified by a single-beam echo sounder system through gas bubbles in the water column. These are more frequent in the northern part of the lake, where wet mofettes spread in a nearly circular-shaped pattern, tracing the crater rim of the northern eruption center of the Laacher See Volcano. Additionally, preferential paths for gas efflux distributed concentrically inside the crater rim are possibly related to volcano-tectonic faults. In the southern part of Laacher See, CO2 vents occur in a high spatial density only within the center of the arc-shaped structure Barschbuckel possibly tracing the conduit of a tuff ring.

  16. Spatiotemporal patterns and source attribution of nitrogen load in a river basin with complex pollution sources.

    Science.gov (United States)

    Yang, Xiaoying; Liu, Qun; Fu, Guangtao; He, Yi; Luo, Xingzhang; Zheng, Zheng

    2016-05-01

    Environmental problems such as eutrophication caused by excessive nutrient discharge are global challenges. There are complex pollution sources of nitrogen (N) discharge in many river basins worldwide. Knowledge of its pollution sources and their respective load contributions is essential to developing effective N pollution control strategies. N loads from all known anthropogenic pollution sources in the Upper Huai River basin of China were simulated with the process-based SWAT (Soil and Water Assessment Tool) model. The performances of SWAT driven by daily and hourly rainfall inputs were assessed and it was found that the one driven by hourly rainfall outperformed the one driven by daily rainfall in simulating both total nitrogen (TN) and ammonia nitrogen (NH4-N) loads. The hourly SWAT model was hence used to examine the spatiotemporal patterns of TN and NH4-N loads and their source attributions. TN load exhibited significant seasonal variations with the largest in summer and the smallest in spring. Despite its declining proportion of contribution downstream, crop production remained the largest contributor of TN load followed by septic tanks, concentrated animal feedlot operations (CAFOs), municipal sewage treatment plants, industries, and scattered animal feedlot operations (SAFOs). There was much less seasonal variation in NH4-N load. CAFOs remained the largest source of NH4-N load throughout the basin, while contributions from industries and municipal sewage treatment plants were more evident downstream. Our study results suggest the need to shift the focus of N load reduction from "end-of-pipe" sewage treatment to an integrated approach emphasizing stakeholder involvement and source prevention. PMID:26945962

  17. Territorial pattern and classification of soils of Kryvyi Rih Iron-Ore Basin

    Directory of Open Access Journals (Sweden)

    О. О. Dolina

    2014-10-01

    Full Text Available The authors developed the classification of soils and adapted it to the conditions of Krivyi Rih industrial region. It became the basis for determining the degree of soil cover transformation in the iron-ore basin under technogenesis. The classification represents the system of hierarchical objects of different taxonomic levels. It allows determination of relationships between objects and their properties. Researched patterns of soil cover structures’ distribution were the basis for the relevant mapping and classification of soils. The classification is adapted to highly-influential industrial conditions of soils formation in the region. The adaptation measures were specific classification levels and units, which provided more detailed differentiation of soils. The authors proposed to separate the soils by the degree of soil formation potential realization for super-divisions. The potential determination allowed predicting the outcome of soil formation and identification of transformation degree of soil cover structures in the region. The results indicated that the main type of soil structures in the industrial region was represented by primitive soils (indicated as a separate type. These soils were determined as dynamic elements in the structure of industrial region soil cover. The article indicated that presence of soil cover structures with the domination of technogenic soils, particularly post-technogenic soils, was the marker of the soil cover in Krivyi Rih Iron-Ore Basin

  18. Changing pattern of heavy rainstorms in the Indus basin of India under global warming scenarios

    Indian Academy of Sciences (India)

    N R Deshpande; B D Kulkarni

    2015-06-01

    Estimation of extremely high rainfall (point or areal) is one of the major components of design storm derivation. The estimation of Probable Maximum Precipitation (PMP) involves selection of heavy rain-storms and its maximization for the moisture content during the rainstorm period. These heavy rain-storms are nothing but the widespread heavy rainfall exceeding a certain threshold value. The present study examines the characteristics of heavy rainstorms in the Indus basin selected from present climate and future scenarios simulated by the regional climate model. Such information on heavy rainfall forms the basis for the hydrologic design projects and also for the water management of a river basin. Emphasis is given to severe rainstorms of 1-day duration covering an area of at least 40,000 km2 with spatial average rainfall of at least 5cm. This analysis also provides the information on the temporal changes in the storm factors such as shape, orientation, and movement, and shows that the model can well simulate the rainstorm pattern in terms of its intensity, orientation, and shape of the rainstorm, but overestimates the frequency of such heavy rainstorms. The future scenario indicates increase in rainfall intensity at the center of the rainstorm with decreasing areal spread. Decrease in the frequency of rainstorms is projected under the global warming conditions.

  19. Regional Trade Agreements: Effects of the Andean and Mercosur Packs on the Venezuelan Soybean Trade and U.S. Exports

    OpenAIRE

    Reeder, John; Torene, Jillian A.; Jabara, Cathy L.; Babula, Ronald A.

    2005-01-01

    Since the mid-1990s, the two regional trade agreements in South America, the southern Mercosur Pact (among Brazil, Argentina, Paraguay and Uruguay), and the northern Andean Pact (among Venezuela, Colombia, Ecuador, Bolivia, and Peru) noticeably affected certain trade patterns between the two pacts' members and with the United States for various reasons discussed herein. The effect of trade diversion owing to the Andean Pact with its common external tariff and price band system against non-And...

  20. Aquifer-specific Rare Earth Element patterns in groundwater of the Thuringian basin, Germany

    Science.gov (United States)

    Lonschinski, M.; Merten, D.; Büchel, G.

    2012-04-01

    The Thuringian basin is the major geological structural unit in the federal state of Thuringia, Germany. It consists of sandstones, limestones, clays, gypsum and salts, that were deposited from the Upper Permian until the Lower Jurassic (approximately 250 to 180 million years ago). The largest deposits are Buntsandstein, Muschelkalk and Keuper, all of Triassic age. Important aquifers are located in the Buntsandstein formations, which are cropping out widespread in the southeastern part and the northeastern part of the basin. These aquifers contain large resources of drinking water for the region. The hydrochemical properties of the groundwater with special emphasis on Rare Earth Elements (REE) are the main focus of this study. To investigate possible interactions between aquifers in the Buntsandstein with aquifers in adjoining formations, waters from Zechstein and Muschelkalk are considered, additionally. Since the REE in water in many case are originated from the minerals of the host rocks, REE fractionation pattern could provide information regarding the lithology of the solid aquifer material (Möller, 2002). Furthermore, interaction processes between solid and liquid phases or complexation in the water phase could be identified by REE fractionations (Ingri et al., 2000). Nevertheless, waters in circumneutral pH conditions could feature many different fractionation patterns (Johannesson & Zhou, 1997) making the interpretation difficult. Due to very low concentrations of REE in water at neutral pH condition, an enrichment procedure is necessary prior to REE determination by inductively coupled plasma mass spectroscopy (ICP-MS). The used method is based on the procedure of Shabani et al. (1990) and yields enrichment factors of about 500. REE fractionation patterns were determined for different water types such as Na-Cl type originating from Zechstein, Ca-Mg-HCO3-SO4 and Ca-SO4 from Buntsandstein or Ca-HCO3 from Muschelkalk aquifers. The patterns are specific for

  1. Patrones de distribución espacial de ensambles de macroinvertebrados bentónicos de un sistema fluvial Andino Patagónico Spatial distribution patterns of benthic macroinvertebrates assemblages in an Andean Patagonian fluvial system

    Directory of Open Access Journals (Sweden)

    CAROLINA MOYA

    2009-01-01

    Full Text Available En enero de 2006 se estudiaron los patrones espaciales de distribución de comunidades de macroinvertebrados bentónicos de la cuenca hidrográfica del río Baker (45°50' O y 47°55' S y los principales factores controladores, intentando cubrir la mayor variedad de ecosistemas lóticos. Para llevar a cabo el estudio se seleccionaron 27 estaciones de muestreo ubicadas en las diferentes subcuencas del río. En cada estación se realizó una caracterización fisicoquímica del agua (conductividad, oxígeno disuelto, pH, temperatura y turbidez, y se documentaron las características del tramo de río (e.g. ancho del cauce y tipo de sedimento e información cartográfica utilizando un sistema de información geográfica (SIG. Se identificaron un total de 51 taxa que correspondieron en su mayoría a larvas de insectos (80 %. Los grupos con mayor riqueza fueron los órdenes Ephemeroptera (15 taxa, Plecoptera (8 taxa y Trichoptera (8 taxa. Los análisis de clasificación y ordenación realizados con los datos de abundancia, permitieron reconocer siete grupos de estaciones diferentes (A-F que fueron estadísticamente significativos (P In January of 2006 we studied the distributional patterns of benthic macroinvertebrate communities of the Baker river basin (45°50' O and 47°55' S and their main controlling factors trying to cover the greater variety of the lotic ecosystems. To carry out the study, 27 sampling stations were located in the different sub basins of the river. In each station, physical-chemical parameters of the column of water were quantified (conductivity, dissolved oxygen, pH, temperature and turbidity, and documented characteristics of the segment (e.g. wide of the channel and sediment type and cartographic information using a geographic information system (GIS and complemented with cartographic information using GIS. Identified a total of 51 taxa, are mostly insect larvae (80 %. The groups most richness were orders Ephemeroptera (15

  2. Modelling the spatial pattern of ground thaw in a small basin in the arctic tundra

    Directory of Open Access Journals (Sweden)

    S. Endrizzi

    2011-01-01

    Full Text Available In the arctic tundra the ground is normally composed by a relatively thin organic soil layer, overlying mineral sediment. Subsurface water drainage generally occurs in the organic layer for its high hydraulic conductivity. However, the organic layer shows significant decrease of hydraulic conductivity with depth. The position and the topography of the frost table, which here acts as a relatively impermeable surface, are therefore crucial in determining the hillslope drainage rate. This work aims at understanding how the topography of the ground surface affects the spatial variability of the depth of thaw in a 1 km2 low-elevation arctic tundra basin with a fine resolution model that fully couples energy and water flow processes. The simulations indicate that the spatial patterns of ground thaw are not dominated by slope and aspect, but are instead entirely controlled by the spatial distribution of soil moisture, which is determined by subsurface flow patterns. Measured thaw depths have a similar range of variability to the simulated values for each stage of active layer development, although the model slightly overestimated the depth of thaw.

  3. Impact of deforestation on local precipitation patterns over the Da River basin, Vietnam

    Science.gov (United States)

    Anghileri, Daniela; Spartà, Daniele; Castelletti, Andrea; Boschetti, Mirco

    2014-05-01

    Change in land cover, e.g. from forest to bare soil, might severely impact the hydrological cycle at the river basin scale by altering the balance between rainfall and evaporation, ultimately affecting streamflow dynamics. These changes generally occur over decades, but they might be much more rapid in developing countries, where economic growth and growing population may cause abrupt changes in landscape and ecosystem. Detecting, analysing and modelling these changes is an essential step to design mitigation strategies and adaptation plans, balancing economic development and ecosystem protection. In this work we investigate the impact of land cover changes on the water cycle in the Da River basin, Vietnam. More precisely, the objective is to evaluate the interlink between deforestation and precipitation. The case study is particularly interesting because Vietnam is one of the world fastest growing economies and natural resources have been considerably exploited to support after-war development. Vietnam has the second highest rate of deforestation of primary forests in the world, second to only Nigeria (FAO 2005), with associated problems like abrupt change in run-off, erosion, sediment transport and flash floods. We performed land cover evaluation by combining literature information and Remote Sensing techniques, using Landsat images. We then analysed time series of precipitation observed on the period 1960-2011 in several stations located in the catchment area. We used multiple trend detection techniques, both state-of-the-art (e.g., Linear regression and Mann-Kendall) and novel trend detection techniques (Moving Average on Shifting Horizon), to investigate trends in seasonal pattern of precipitation. Results suggest that deforestation may induce a negative trend in the precipitation volume. The effect is mainly recognizable at the beginning and at the end of the monsoon season, when the local mechanisms of precipitation formation prevail over the large scale

  4. SEDIMENTARY PATTERN OF PROTOTYPE BASIN IN THE DEPOSITION PERIOD OF LAIYANG FORMATION AND THE ADVANTAGEOUS AREAS FOR OIL AND GAS EXPLORATION OF JIAOLAI BASIN

    Institute of Scientific and Technical Information of China (English)

    WU Zhiping; LI Ling; LI Wei; ZHOU Yaoqi

    2004-01-01

    Laiyang formation of Jiaolai Basin is the target stratum for oil and gas exploration. By measuring several field sections, the authors find that Laiyang formation reveals the whole processes from development to death of the lake basin and its sedimentary facies differ in different structural locations.Analyses about sedimentary facies and paleocurrent orientations in association with researches about the positive tectonic units such as Dayetou horseback and Chaigou horst indicate that Laiyang sag is a relatively independent sedimentary unit that shows great water depth typical of deep lake or semideep lake and was controlled by Wulongcun fault during the deposition period of Laiyang formation. Its sediments mainly originated from Jiaobei uplift area and Dayetou horseback. Gaomi-Zhucheng sag was a fast-filled basin controlled by Wurong fault and Yishu fault zone, being high in the northeast and low in the northwest and characterized by the development of pluvial facies and fluvial facies in most areas, and with the development of lake facies being limited to local low-lying regions. Selection of advantageous hydrocarbon reservoir areas for exploration purpose mainly relies on the sedimentation pattern of prototype basin and conservation conditions. The central-west area of Laiyang sag covered by overlying Laiyang formation is the most advantageous exploration area.

  5. A review on tectonic record of strain buildup and stress release across the Andean forearc along the Gulf of Guayaquil-Tumbes basin (GGTB) near Ecuador-Peru border

    OpenAIRE

    2013-01-01

    Gravimetric and geologic data show that the reactivation of the Neogene Interandean depression and/or the ~75 - 65 Ma ophiolite suture into the modern dynamic of the Andes controlled the Gulf of Guayaquil Tumbes basin (GGTB) location and evolution during the past 1.8 - 1.6 Myr at least. Depending on whether the remobilization occurred along the in- terandean depression or the ophiolite suture, the GGTB evolved trough pure or simple shear mechanisms, respectively. Because the GGTB exhibits an ...

  6. Climate and local geomorphic interactions drive patterns of riparian forest decline along a Mediterranean Basin river

    Science.gov (United States)

    Stella, John C.; Riddle, Jess; Piégay, Hervé; Gagnage, Matthieu; Trémélo, Marie-Laure

    2013-11-01

    Dynamic fluvial processes strongly influence ecological communities and ecosystem health in riverine and riparian ecosystems, particularly in drought-prone regions. In these systems, there is a need to develop tools to measure impacts from local and regional hydrogeomorphic changes on the key biological and physical processes that sustain riparian ecosystem health and potential recovery. We used dendrochronology of Populus nigra, a riparian tree that is vulnerable to changes in local hydrology, to analyze ecosystem response following channel incision due to gravel mining along the Drôme River, a Mediterranean Basin stream in southern France. We cored 55 trees at seven floodplain sites, measured ring widths, and calculated basal area growth to compare the severity and timing of local growth decline along the river. Current basal area increment (BAI) growth per tree ranged almost 10-fold among sites (7.7 ± 1.3 to 63.9 ± 15.2 cm2 year- 1, mean ± SE) and these differences were significant. Mean BAI was correlated positively with the proportion of healthy trees at a site, and negatively with proportion of dead canopy area. Regime shift analysis of the tree-ring series indicates that tree growth declined significantly at four sites since 1978, coincident with documented channel incision. In addition, patterns of low growth and crown dieback are consistent with stress due to reduced water supply. The most impaired sites were not directly adjacent to local mining pits visible on aerial photographs, nor did the sequence of growth regime shifts suggest a pattern of channel incision progressing from these areas. The initiation of site growth declines was most typically associated with drought years, and the most impaired sites were spatially distributed to suggest the influence of local bedrock controls on soil depth. Climate in the Drôme basin and in the Mediterranean region is trending significantly toward hotter growing seasons with a decrease in summer river

  7. Vegetation Carbon Storage, Spatial Patterns and Response to Altitude in Lancang River Basin, Southwest China

    Directory of Open Access Journals (Sweden)

    Long Chen

    2016-01-01

    Full Text Available Vegetation plays a very important role of carbon (C sinks in the global C cycle. With its complex terrain and diverse vegetation types, the Lancang River Basin (LRB of southwest China has huge C storage capacity. Therefore, understanding the spatial variations and controlling mechanisms of vegetation C storage is important to understand the regional C cycle. In this study, data from a forest inventory and field plots were used to estimate and map vegetation C storage distribution in the LRB, to qualify the quantitative relationships between vegetation C density and altitude at sublot and township scale, and a linear model or polynomial model was used to identify the relationship between C density and altitude at two spatial scales and two statistical scales. The results showed that a total of 300.32 Tg C was stored in the LRB, an important C sink in China. The majority of C storage was contributed by forests, notably oaks. The vegetation C storage exhibited nonlinear variation with latitudinal gradients. Altitude had tremendous influences on spatial patterns of vegetation C storage of three geomorphological types in the LRB. C storage decreased with increasing altitude at both town and sublot scales in the flat river valley (FRV region and the mid-low mountains gorge (MMG region, and first increased then decreased in the alpine gorge (AG region. This revealed that, in southwest China, altitude changes the latitudinal patterns of vegetation C storage; especially in the AG area, C density in the mid-altitude (3100 m area was higher than that of adjacent areas.

  8. Malaria transmission and morbidity patterns in holoendemic areas of Imo River Basin of Nigeria

    Directory of Open Access Journals (Sweden)

    Chukwuocha Uchechukwu M

    2011-11-01

    Full Text Available Abstract Background This study determines the relationship between malaria transmission intensity and morbidity in holoendemic areas of Imo River Basin, Nigeria. Results Standard entomological and parasitological techniques were used to determine transmission intensity and parasite rates respectively while sociocultural methods and review of hospital records were used to determine morbidity patterns. The average transmission rate was 16.1 infective bites per person per night (ib/p/n. The average malaria specific morbidity rate for the study area was 30.2%. These parameters showed no significant differences among the communities studied (P > 0.05. Transmission intensity and morbidity rate had a linear relationship such that high transmission intensity corresponded with high morbidity rate and vice versa. Conclusions This therefore puts to rest discrepancies about the relationship between malaria transmission and morbidity in the study area and calls for serious scaling up of the insecticide treated nets strategy especially in high transmission areas and seasons. Concerted efforts should also be made towards production of transmission blocking vaccines.

  9. Long-term and wide-area subsidence pattern from time series of Envisat Asar Data in Konya Basin, Turkey

    Science.gov (United States)

    Ustun, Aydin

    2016-04-01

    Konya Basin as a sub-part of Konya Closed Basin is dominated by the Neogene and Quaternary sediments that are largely fluvial and lacustrine characteristic. The wide plains cultivated over the last 10000 years are the remnants of the Pluvial lake basin during wet and humid climate environment after the last glacial period. With the form of isolated depression-block, the geomorphological landscape has been mainly driven by the neotectonic activity of striking normal fault systems of the region. Konya that has doubled in size over the last two and half decades is both expanding into the agricultural areas and increasing its building expansion in the city center. The level observations recorded at the monitoring stations indicate that groundwater resources have been exploited permanently or seasonally in some parts where water demand exceeds supply. In this study, a long-term and wide area subsidence pattern in Konya Basin has been analyzed by stacking the deformation interferograms for time series. The study area that covers approximately 7500 km squared was investigated through a large number of the raw images of Asar sensor onboard Envisat from December 2002 to October 2010. Almost a hundred SAR scenes imaged over three tracks in both ascending and descending modes have been used to create a set of 127 differential interferograms using GMTSAR processing system. A continuous deformation map on the basinwide scale has been produced by combining the stacked interferograms. The average contour map shows that the DInSAR detected line of sight subsidence (or uplift) rates vary between 0.6 and -3.3 cm/yr throughout 8 years. The subsidence pattern significantly is correlated with the land and groundwater use within the basin and it states that the anthropogenic effect is much greater than the identified geological and hydrogeological processes.

  10. Administrative Law in the Andean Community of Nations

    Directory of Open Access Journals (Sweden)

    Jorge Enrique Santos Rodríguez

    2013-12-01

    Full Text Available One of the contemporary tendencies of Administrative Law is the recognition of its existence beyond the borders of a State. Under such premise, this paper aims to demonstrate that in the Andean Community of Nations sufficient elements to consider the existence of an Andean administrative Law. In the Andean statutes and rules, it is possible to identify an administrative function, as well as an administrative organization inside the Andean Integration System; and a system of Andean administrative rules and an administrative justice system.

  11. Benthic communities in the deep Mediterranean Sea: exploring microbial and meiofaunal patterns in slope and basin ecosystems

    Directory of Open Access Journals (Sweden)

    K. Sevastou

    2012-12-01

    Full Text Available The long held perception of the deep sea consisting of monotonous slopes and uniform oceanic basins has over the decades given way to the idea of a complex system with wide habitat heterogeneity. Under the prism of a highly diverse environment, a large dataset was used to describe and compare spatial patterns of the dominant small-size components of deep-sea benthos, metazoan meiofauna and bacteria, from Mediterranean basins and slopes. A grid of 73 stations sampled at five geographical areas along the central-eastern Mediterranean basin (central Mediterranean, northern Aegean Sea, Cretan Sea, Libyan Sea, eastern Levantine spanning over 4 km in depth revealed a high diversity in terms of both metazoan meiofauna and microbial communities. The higher meiofaunal abundance and richness observed in the northern Aegean Sea highlights the effect of productivity on benthic patterns. Non parametric analyses detected no differences for meiobenthic standing stocks and major taxa diversity (α, β, γ and δ components between the two habitats (basin vs. slope for the whole investigated area and within each region, but revealed significant bathymetric trends: abundance and richness follow the well-known gradient of decreasing values with increasing depth, whereas differentiation diversity (β- and δ-diversity increases with depth. In spite of a similar bathymetric trend observed for nematode genera richness, no clear pattern was detected with regard to habitat type; the observed number of nematode genera suggests higher diversity in slopes, whereas richness estimator Jack1 found no differences between habitats. On the other hand, δ-diversity was higher at the basin habitat, but no differences were found among depth ranges, though turnover values were high in all pairwise comparisons of the different depth categories. Results of multivariate analysis are in line with the above findings, indicating high

  12. Australasian microtektites from the Central Indian Basin: Implications for ejecta distribution patterns

    Digital Repository Service at National Institute of Oceanography (India)

    ShyamPrasad, M.; Sudhakar, M.

    Microtektites belonging to the Australasian tektite strewn field have been recovered in one (SK-16/176) out of three cores examined from the Central Indian Basin. The microtektites have been identified based on their physical appearance...

  13. Architecture and facies pattern of a sublacustrine fan, Jharia Basin, India

    Science.gov (United States)

    Dasgupta, Prabir

    2002-05-01

    A small sublacustrine fan deposit has been identified within a lacustrine succession belonging to the Barren Measure Formation (Middle Permian) of the Lower Gondwana deposits of Jharia Basin, India. The stratigraphic position of the fan and its structural relationship with the associated sediments suggest that the east-west aligned elongate trough formed in the central part of the basin experienced intrabasinal normal faulting of limited lateral extent, and accumulation of clastic input within the associated hangingwall syncline led to formation of this deposit. Three major framework components can be identified within this deposit: (a) sheet-like sandstone aprons, (b) channel-fill sandbodies and (c) lensoid massive beds of pebbly sandstone. The laterally extensive sheet-like bodies of sandstone, covering almost the whole of the older sediments, appear to be the product of deposition from unconfined sediment-laden flows during episodic flood events. The proximal part of the deposit is dominated by the successive deposition of sandstone aprons with a few channel plug sandbodies produced through rapid sedimentation from channelised sediment-laden turbulent flows. The distal part, on the other hand, is mainly represented by the stacked channel-fills with alternate sandstone aprons. Following the deposition of bedded sandstones, as the slope of the depositional surface reduced, turbulent flows with relatively less grain concentration extended towards the ambient waterbody through channels incised into the preexisting unconsolidated sediments. During this process of incision, the flows gradually became hyperconcentrated. The channels were ultimately filled-in by concordant bedsets in approximate conformity with the shape of the channel, either through bedload deposition or suspension fall-out from these submerged currents. A few massive channel-fills, indicating emplacement of liquefied sandflows, caused by slope instability during high-flood event, are also present

  14. Andean highlands: Implications of climate change

    OpenAIRE

    Seth, Anji; Thibeault, J.M.; García, Magali

    2007-01-01

    This presentation provides background on the SANREM CRSP project "Adapting to Change in the Andean Highlands: Practices and Strategies to Address Climate and Market Risks in Vulnerable Agro-Eco Systems" and discusses the means, variability and projections for the Altiplano climate. available in SANREM office, ESIILTRA-4 (Practices and Strategies for Vulnerable Agro-Ecosystems)

  15. Spatial distribution pattern and dynamics of the primary population in a natural Populus euphratica forest in Tarim Basin, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    Lu HAN; Haizhen WANG; Zhengli ZHOU; Zhijun LI

    2008-01-01

    One 50 m × 50 m standard plot was sampled in a natural forest of Populus euphratica in Awati County, situated at the edge of the Tarim Basin, Xinjiang Uygur Autonomous Region, China. The field investigation was conducted with a contiguous grid quadrate method. By means of a test of variance/mean value ratio, aggregation intensity index and theoretical distribution models, the spatial distribution pattern and the dynamics of primary populations in P. euphratica forest were studied. The results showed that the spatial distribution pattern of two dominant arbor populations conformed to clumped distribution. The aggregation intensity of the P. euphra-tica population was higher than that of P. pruinosa popu- lation. The spatial distribution pattern of two companion plant populations in the shrub layer also conformed to clump type, though the aggregation intensity of Tamarix chinensis was higher. In the herb layer, the distribution patterns of Glycyrrhiza uralensis and Asparagus persicus conformed respectively to a clumped pattern and a ran-dom pattern. The results of a Taylor power method test and Iwao's m2-x regression model also verified that both P. euphratica and P. pruinosa populations belong to a clumped pattern. Although the distribution pattern of P. pruinosa population at different development stages all belonged to a clumped distribution pattern, the aggrega-tion intensity dropped gradually along with age develop-ment. The distribution patterns of the P. euphratica population at different development stages changed from random type to clumped type, and further to random type. The differences in spatial distribution patterns of different populations at different development stages were related not only to ecological and biological characteris-tics of each species in the communities in the light of competitive exclusion principle among the populations, but were also closely related to the habitats in which the species lived in.

  16. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity.

    Directory of Open Access Journals (Sweden)

    Matt Finer

    Full Text Available Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1 There is a critical need for further strategic regional and basin scale evaluation of dams. 2 There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3 Reconsideration of hydropower as a low-impact energy source in the Neotropics.

  17. Proliferation of Hydroelectric Dams in the Andean Amazon and Implications for Andes-Amazon Connectivity

    Science.gov (United States)

    Finer, Matt; Jenkins, Clinton N.

    2012-01-01

    Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1) There is a critical need for further strategic regional and basin scale evaluation of dams. 2) There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3) Reconsideration of hydropower as a low-impact energy source in the Neotropics. PMID:22529979

  18. PATTERNS AND TOURIST ACTIVITIES INDUCED BY THE UNDERGROUND RIVERS AND LAKES IN THE ARIEŞ BASIN UPSTREAM OF BURU

    Directory of Open Access Journals (Sweden)

    Marius CIGHER

    2011-11-01

    Full Text Available Patterns and tourist activities induced by the underground rivers and lakes in the Arieş basin upstream of Buru – The presence of carbonate deposits in the Arieş basin, upstream of Buru induced certain organization of groundwater resources. Depending on local genetic factors – geological, climatic, biotic, temporal, etc – the extension and characteristics of karst aquifers engenders exploitable hydro units in terms of tourism: underground rivers and lakes. Identification and analysis of morphometrical, morphological, quantitative, qualitative, dynamic and biotic characteristics have provided the approach to ranking the hydro entities. Forms and tourism activities are subsumed to the established typological categories: recreational and pleasure tourism and multipurpose tourism.

  19. Spatially variant lagged responses of forest extent and landscape patterns to socioeconomic drivers in the Li River Basin, China

    Science.gov (United States)

    Zhang, Yuan; Li, Jun; Qin, Qiming; Xu, Ruofeng; Lin, Cong

    2016-01-01

    Forest cover change is one of the most important land cover changes. Intensified economic development and population growth have led to extensive deforestation and afforestation, and greatly altered the forest landscape patterns. This paper analyzed how socioeconomic drivers influenced the forest extent and landscape patterns in a lagged manner within the Li River Basin, Guangxi Zhuang Autonomous Region, China, during the period of 1991 to 2013. First, the temporal variations of forest extent and landscape patterns as quantified by six forest cover metrics were analyzed. The cross-correlation analysis was employed to examine the lagged responses of forest cover metrics to each socioeconomic driver across regions. Last, the fixed effects regression models were built to quantitatively assess the spatially variant relationships. The results demonstrated that the influence of socioeconomic drivers lagged, and the lagged influence varied across regions.

  20. Climatic gradients and human development pressure determine spatial patterns of forest fragmentation in the Great Lakes basin, USA

    Science.gov (United States)

    Currie, W. S.; Hart, S.

    2015-12-01

    Over half of temperate forest area globally has been fragmented or deforested by human activities. Our objective was to gain insight into the combination of climatic, ecological, and social factors that control complex spatial patterns of forest cover and fragmentation at the regional scale. Our study area was the US portion of the land area of the Laurentian Great Lakes basin (USGL basin) of the Upper Midwest, USA, covering ca. 300,000 km2 and home to 25 million people. While this region was historically forested, today there are regional gradients in forest cover as well as complex spatial patterns of agriculture, human settlements, and tree cover. This includes large expanses of fragmented forests in the wildland-urban interface or the forest transition zone. We used structural equation modeling to test models of social and climatic-ecological factors to explain spatial patterns of forest cover and fragmentation. This is a model-driven approach to statistical analysis that is used to test proposed causal "structures" of direct and indirect relationships among variables. It is an innovative approach that makes use of large spatial datasets to test understanding. We assembled numerous spatial data layers at 1 km2 resolution across the USGL basin. We found that 64% to 75% of variance in tree cover and forest connectivity was explained through a relatively simple model combining climatic gradients and human development pressure. Human development pressure was best represented as a measurement model that explained 45% of variance in road density and 87% of housing unit density, while significantly explaining patterns of forest fragmentation. Climate could be represented by a single variable, temperature: where temperature was higher, tree cover and forest connectivity was lower due to human land use. Temperatures did not help to explain patterns of human development as roads and housing, but did affect forest fragmentation through land use as cropland. This suggests

  1. North Atlantic Basin Tropical Cyclone Activity in Relation to Temperature and Decadal- Length Oscillation Patterns

    Science.gov (United States)

    Wilson, Robert M.

    2009-01-01

    Yearly frequencies of North Atlantic basin tropical cyclones, their locations of origin, peak wind speeds, average peak wind speeds, lowest pressures, and average lowest pressures for the interval 1950-2008 are examined. The effects of El Nino and La Nina on the tropical cyclone parametric values are investigated. Yearly and 10-year moving average (10-yma) values of tropical cyclone parameters are compared against those of temperature and decadal-length oscillation, employing both linear and bi-variate analysis, and first differences in the 10-yma are determined. Discussion of the 2009 North Atlantic basin hurricane season, updating earlier results, is given.

  2. Nonuniform surface uplift of the Andean plateau revealed by deuterium isotopes in Miocene volcanic glass from southern Peru

    Science.gov (United States)

    Saylor, Joel E.; Horton, Brian K.

    2014-02-01

    Proposals for rapid late Miocene surface uplift driven by large-scale lithospheric removal beneath the central Andean plateau have been based largely on temperature-sensitive paleoaltimeters. Both the magnitude and mechanism of this proposed pulse of uplift have been challenged. First, climatic general circulation models support protracted uplift with predicted temperature and isotopic shifts enhanced by attainment of threshold elevations. Second, tectonic models in which surface elevations are compensated by regional contraction and crustal thickening question the need for lithospheric removal and predict broadly coeval uplift of the entire plateau. We present hydrogen isotope data using a novel temperature-insensitive volcanic glass proxy from continuous, well-dated lower to middle Miocene basin fill in the Western Cordillera of the northern plateau that show a rapid decrease in δD values (-62.8‰) at 19-16 Ma, with extremely negative values continuing into the Pliocene. We propose that the basin reached its current elevation by 16 Ma, >6 Myr earlier than proposed for the central plateau. The rapid decrease in δD values is consistent with punctuated surface uplift of 2.2-3.7 km between 19 and 16 Ma. Whereas the 3.7 km upper estimate assumes a static climate similar to modern, the 2.2 km lower estimate conservatively incorporates modeled changes in the isotopic composition of precipitation associated with elevation change. Comparison of these results to existing paleoelevation estimates from the Andean plateau facilitates a tentative reconstruction of earliest middle Miocene paleotopography showing a central depression with flanking hinterland and thrust-belt highlands. This apparent pattern of nonuniform plateau uplift contradicts shortening-proportional topographic growth over tens of Myr. We propose that temporally and spatially irregular surface uplift may be linked to pronounced local variability in crustal shortening and/or piecemeal removal of dense

  3. Contrasting patterns of river runoff and sea-ice melted water in the Canada Basin

    Institute of Scientific and Technical Information of China (English)

    TONG Jinlu; CHEN Min; QIU Yusheng; LI Yanping; CAO Jianping

    2014-01-01

    The fractions of river runoff and sea-ice melted water in the Canada Basin in summer 2003 were determined by the salinity-δ18O system. The fraction of river runoff (fR) was high in the upper 50 m of the water column and decreased with depth and latitude. The signals of the river runoff were confined to water depths above 200 m. The total amount of river runoff in the Canada Basin was higher than that in other arctic seas, indi-cating that the Canada Basin is a main storage region for river runoff. The penetration depth of the sea-ice melted water was less than 50 m to the south of 78°N, while it was about 150 m to the north of 78°N. The total amount of sea-ice melted water was much higher to the north of 78°N than to the south of 78°N, indicating the sea-ice melted waters accumulated on the ice edge. The abundant sea-ice melted water on the ice edge was attributed to the earlier melted water in the southern Canada Basin and transported by the Beaufort Gyre or the reinforced melting of sea ice by solar radiation in the polynya.

  4. Water use patterns and conservation in households of Wei River Basin, China

    NARCIS (Netherlands)

    Fan, L.; Liu, G.; Wang, F.; Geissen, V.; Ritsema, C.J.

    2013-01-01

    Fully understanding patterns of water use and water conservation among different consumer groups will help in implementing more effective water conservation programs worldwide. Consequently, we investigated water use patterns, water conservation practices, attitudes, and hindrances to water conserva

  5. Diversity and ecological ranges of plant species from dry inter-Andean valleys

    DEFF Research Database (Denmark)

    Quintana, Catalina

    animals, but unfortunately only very few botanical studies have been carried out in these areas. This thesis intends to shed light on the vegetation of the Dry Ecuadorean Inter-Andean Valleys in four chapters, each with a different focus. 1) A review paper that summarizes all scientific knowledge of...... Ecuadorian dry inter-Andean valleys vegetation, including information related to the physical settings as well as to the vegetation and flora of the valleys. 2) This chapter unveils the influence of disturbance, water availability and low temperature in shaping species composition and occurrence. We found...... that there were significant, contrasting patterns between life forms (trees, herbs and shrubs) and that combining trees and shrubs in one broad category confound patterns and ecological processes. 3) This paper demonstrates that 70% of species collected in Ecuadorian DIAVs are shared amongst dry...

  6. A new Andean species of Philodryas (Dipsadidae, Xenodontinae) from Ecuador.

    Science.gov (United States)

    Zaher, Hussam; Arredondo, Juan C; Valencia, Jorge H; Arbeláez, Ernesto; Rodrigues, Miguel T; Altamirano-Benavides, Marco

    2014-01-01

    We describe a new species of Philodryas from the highlands of southern Ecuador. The new species is distinguished from all known species of Philodryas by a unique combination of coloration, scalation, and hemipenial characters. The new species resembles Philodryas simonsii in color pattern. However, they differ notoriously by their hemipenial morphology. The three other trans-Andean members of the genus (Philodryas simonsii, Philodryas chamissonis, and Philodryas tachymenoides), along with the new species, compose a probably monophyletic group that may be characterized by the presence of ungrooved postdiastemal teeth in the maxilla. Unlike most species of the genus Philodryas, the new species shows a restricted distribution, being apparently endemic to a small region of high-altitude (3150-4450m) grasslands in the southern Andes of Ecuador. PMID:24872238

  7. Spatial gradients in freshwater fish diversity, abundance and current pattern in the Himalayan region of Upper Ganges Basin, India

    Directory of Open Access Journals (Sweden)

    AJEY KUMAR PATHAK

    2014-10-01

    Full Text Available Pathak AK, Sarkar UK, Singh SP. 2014. Spatial gradients in freshwater fish diversity, abundance and current pattern in the Himalayan region of Upper Ganges Basin, India. Biodiversitas 15: 186-194.The present study describes the analysis and mapping of the different measurements of freshwater fish biodiversity of the Upper Ganges basin in the Himalayan region using spatial interpolation methods of Geographical Information System. The diversity, richness and abundance of fishes for each sampling location were determined and Kriging interpolation was applied on each fisheries measurement to predict and produce semivariogram. The semivariogarms produced were cross validated and reclassified. The reclassified maps for richness, abundance and diversity of fishes, occurrence of cold water threatened fish and abundance of important genera like Tor, Schziothorax and species were produced. The result of the Kriging produced good results and overall error in the estimation process was found significant. The cross validation of semovariograms also provided a better result with the observed data sets. Moreover, weighted overlay analysis of the reclassified raster maps of richness and abundance of fishes produced the classified raster map at different evaluation scale (0-10 qualitatively describing the gradient of species richness and abundance compositely. Similarly, the classified raster map at same evaluation scale qualitatively describing the gradient of species abundance and diversity compositely was produced and published. Further, basin wise analysis between Alaknanda/Pindar and Ganga1 sub basins showed 0.745 disparities at 0.745 distances in 2 dimensional spaces. The richness, diversity and abundance of threatened fishes among the different sampling locations were not significant (p = 0.9.

  8. Stress distribution and seismicity patterns of the 2011 seismic swarm in the Messinia basin, (South-Western Peloponnesus, Greece

    Directory of Open Access Journals (Sweden)

    G. Chouliaras

    2013-01-01

    Full Text Available In this investigation we examine the local stress field and the seismicity patterns associated with the 2011–2012 seismicity swarm in the Messinia basin, south-western Peloponnesus, Greece, using the seismological data of the National Observatory of Athens (NOA. During this swarm more than 2000 events were recorded in a 12 month period by the Hellenic Unified Seismological Network (HUSN and also by the additional local installation of four portable broadband seismographic stations by NOA.

    The results indicate a Gaussian distribution of swarm activity and the development of a seismicity cluster in a pre-existing seismic gap within the Messinia basin. Centroid Moment Tensor solutions demonstrate a normal fault trending northwest–southeast and dipping to the southwest primarily due to an extensional stress field. During this seismicity swarm an epicentre migration of the three largest shocks is observed, from one end of the rupture zone in the north-western part of the cluster, towards the other edge of the rupture in the south-eastern part of the cluster. This migration is found to follow the Coulomb failure criterion that predicts the advancement and retardation of the stress field and the patterns of increases and decreases of the seismicity rate (b-value of the frequency–magnitude relation.

  9. Radiometric profiles of uranium dispersal pattern adjacent to cretaceous phosphatic sediments in Wadi Qasser Al-Hallabat basin, central Syria

    International Nuclear Information System (INIS)

    A radiometric survey was carried out over clastic sediments in the immediate vicinity of some phosphatic sediments of Cretaceous age in the Wadi Qasser Al-Hallabat basin of central Syria. the objective was to explore for uranium and to define its dispersion pattern. This was based on ground radiometric surveys and geological studies. All ground surveys (using radon emanometry, track etching, gamma-ray survey and geochemistry) gave similar results outlining the locations of the radioactive phosphatic formations in the basin, and indicating the dispersion pattern of uranium in the clastic sediments in the surrounding area. The dispersal of uranium from upper Cretaceous phosphatic formation occurs by mechanical weathering and chemical leaching by oxidizing surface waters. A rough estimate is that about one-third of the original uranium content of the cretaceous sediments has been dispersed. Mechanical erosion is responsible for the main part of this released uranium, which now occurs in Recent sediments. However, the occurrences of spotty secondary U mineralization indicates that another small part of the available uranium must have been chemically leached out by the prevailing oxidizing waters, forming minor surficial minerals. (Author)

  10. Spatial pattern formation and intraspecific competition of anabasis aphylla l. population in the diluvial fan of junggar basin, nw china

    International Nuclear Information System (INIS)

    Using conventional nearest neighbour analysis and Ripley's L-function, the goal of this study was to analyze spatial patterns of Anabasis aphylla plants in order to investigate underlying competitive processes that shape the population spatial structure from diluvial fan in Junggar Basin, NW China. We found that the spatial patterns of all growth stages were aggregated in the three study plots, and seedling and juvenile plants were more aggregated than expected by chance. Positive associations among growth stages of A. aphylla population were found at a small scale while negative associations of seedling and juvenile relative to adult plants were shown at a larger scale. The processes such as dispersal, seedling establishment, environmental heterogeneity, plant interactions and disturbance may have acted individually or in concert with other processes to produce the aggregated patterns and competitive relationship. Moreover, these findings suggested that the aggregated distribution and the competitive interaction between A. aphylla plants in the diluvial fan reflected not only in mortality, but also in decreased performance (smaller canopy) that was an important characteristic of drought-enduring plant, thus preventing a regular distribution pattern. (author)

  11. Volcanism and associated hazards: the Andean perspective

    Directory of Open Access Journals (Sweden)

    R. I. Tilling

    2009-12-01

    Full Text Available Andean volcanism occurs within the Andean Volcanic Arc (AVA, which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions" recognized worldwide that have occurred from the Ordovician to the Pleistocene.

    The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru. The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (<0.05 km3 in 1985 of Nevado del Ruiz (Colombia killed about 25 000 people – the worst volcanic disaster in the Andean region as well as the second worst in the world in the 20th century. The Ruiz tragedy has been attributed largely to ineffective communications of hazards information and indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent

  12. Migratory Patterns of Wild Chinook Salmon Oncorhynchus tshawytscha Returning to a Large, Free-Flowing River Basin.

    Directory of Open Access Journals (Sweden)

    John H Eiler

    Full Text Available Upriver movements were determined for Chinook salmon Oncorhynchus tshawytscha returning to the Yukon River, a large, virtually pristine river basin. These returns have declined dramatically since the late 1990s, and information is needed to better manage the run and facilitate conservation efforts. A total of 2,860 fish were radio tagged during 2002-2004. Most (97.5% of the fish tracked upriver to spawning areas displayed continual upriver movements and strong fidelity to the terminal tributaries entered. Movement rates were substantially slower for fish spawning in lower river tributaries (28-40 km d-1 compared to upper basin stocks (52-62 km d-1. Three distinct migratory patterns were observed, including a gradual decline, pronounced decline, and substantial increase in movement rate as the fish moved upriver. Stocks destined for the same region exhibited similar migratory patterns. Individual fish within a stock showed substantial variation, but tended to reflect the regional pattern. Differences between consistently faster and slower fish explained 74% of the within-stock variation, whereas relative shifts in sequential movement rates between "hares" (faster fish becoming slower and "tortoises" (slow but steady fish explained 22% of the variation. Pulses of fish moving upriver were not cohesive. Fish tagged over a 4-day period took 16 days to pass a site 872 km upriver. Movement rates were substantially faster and the percentage of atypical movements considerably less than reported in more southerly drainages, but may reflect the pristine conditions within the Yukon River, wild origins of the fish, and discrete run timing of the returns. Movement data can provide numerous insights into the status and management of salmon returns, particularly in large river drainages with widely scattered fisheries where management actions in the lower river potentially impact harvests and escapement farther upstream. However, the substantial variation

  13. Central Andean crustal structure from receiver function analysis

    Science.gov (United States)

    Ryan, Jamie; Beck, Susan; Zandt, George; Wagner, Lara; Minaya, Estela; Tavera, Hernado

    2016-07-01

    The Central Andean Plateau (15°-27°S) is a high plateau in excess of 3 km elevation, associated with thickened crust along the western edge of the South America plate, in the convergent margin between the subducting Nazca plate and the Brazilian craton. We have calculated receiver functions using seismic data from a recent portable deployment of broadband seismometers in the Bolivian orocline (12°-21°S) region and combined them with waveforms from 38 other stations in the region to investigate crustal thickness and crust and mantle structures. Results from the receiver functions provide a more detailed map of crustal thickness than previously existed, and highlight mid-crustal features that match well with prior studies. The active volcanic arc and Altiplano have thick crust with Moho depths increasing from the central Altiplano (65 km) to the northern Altiplano (75 km). The Eastern Cordillera shows large along strike variations in crustal thickness. Along a densely sampled SW-NE profile through the Bolivian orocline there is a small region of thin crust beneath the high peaks of the Cordillera Real where the average elevations are near 4 km, and the Moho depth varies from 55 to 60 km, implying the crust is undercompensated by ~ 5 km. In comparison, a broader region of high elevations in the Eastern Cordillera to the southeast near ~ 20°S has a deeper Moho at ~ 65-70 km and appears close to isostatic equilibrium at the Moho. Assuming the modern-day pattern of high precipitation on the flanks of the Andean plateau has existed since the late Miocene, we suggest that climate induced exhumation can explain some of the variations in present day crustal structure across the Bolivian orocline. We also suggest that south of the orocline at ~ 20°S, the thicker and isostatically compensated crust is due to the absence of erosional exhumation and the occurrence of lithospheric delamination.

  14. Genetic diversity of Phytophthora infestans in the Northern Andean region

    Directory of Open Access Journals (Sweden)

    Grünwald Niklaus J

    2011-02-01

    Full Text Available Abstract Background Phytophthora infestans (Mont. de Bary, the causal agent of potato late blight, is responsible for tremendous crop losses worldwide. Countries in the northern part of the Andes dedicate a large proportion of the highlands to the production of potato, and more recently, solanaceous fruits such as cape gooseberry (Physalis peruviana and tree tomato (Solanum betaceum, all of which are hosts of this oomycete. In the Andean region, P. infestans populations have been well characterized in Ecuador and Peru, but are poorly understood in Colombia and Venezuela. To understand the P. infestans population structure in the Northern part of the Andes, four nuclear regions (ITS, Ras, β-tubulin and Avr3a and one mitochondrial (Cox1 region were analyzed in isolates of P. infestans sampled from different hosts in Colombia and Venezuela. Results Low genetic diversity was found within this sample of P. infestans isolates from crops within several regions of Colombia and Venezuela, revealing the presence of clonal populations of the pathogen in this region. We detected low frequency heterozygotes, and their distribution patterns might be a consequence of a high migration rate among populations with poor effective gene flow. Consistent genetic differentiation exists among isolates from different regions. Conclusions The results here suggest that in the Northern Andean region P. infestans is a clonal population with some within-clone variation. P. infestans populations in Venezuela reflect historic isolation that is being reinforced by a recent self-sufficiency of potato seeds. In summary, the P. infestans population is mainly shaped by migration and probably by the appearance of variants of key effectors such as Avr3a.

  15. Trench-parallel flow and seismic anisotropy in the Mariana and Andean subduction systems.

    Science.gov (United States)

    Kneller, Erik A; van Keken, Peter E

    2007-12-20

    Shear-wave splitting measurements above the mantle wedge of the Mariana and southern Andean subduction zones show trench-parallel seismically fast directions close to the trench and abrupt rotations to trench-perpendicular anisotropy in the back arc. These patterns of seismic anisotropy may be caused by three-dimensional flow associated with along-strike variations in slab geometry. The Mariana and Andean subduction systems are associated with the largest along-strike variations of slab geometry observed on Earth and are ideal for testing the link between slab geometry and solid-state creep processes in the mantle. Here we show, with fully three-dimensional non-newtonian subduction zone models, that the strong curvature of the Mariana slab and the transition to shallow slab dip in the Southern Andes give rise to strong trench-parallel stretching in the warm-arc and warm-back-arc mantle and to abrupt rotations in stretching directions that are accompanied by strong trench-parallel stretching. These models show that the patterns of shear-wave splitting observed in the Mariana and southern Andean systems may be caused by significant three-dimensional flow induced by along-strike variations in slab geometry. PMID:18097407

  16. Rare earth element patterns of the Central Indian Basin sediments related to their lithology

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.; Roelandts, I.; Sudhakar, M.; Pluger, W.L.

    with terrigenous sediments, positive Ce anomalies with siliceous sediments, negative Ce and positive Eu anomalies with calcareous sediments, and LREE-depleted patterns with pelagic red clays. There is no relation of any REE fractionation to bottom water redox...

  17. 75 FR 6679 - Agency Information Collection Activities: Andean Trade Preferences

    Science.gov (United States)

    2010-02-10

    ... Register (74 FR 65543) on December 10, 2009, allowing for a 60- day comment period. This notice allows for... officers to document preferential tariff treatment under the provisions of the Andean Trade Preferences Act... SECURITY U.S. Customs and Border Protection Agency Information Collection Activities: Andean...

  18. Seismic volcanostratigraphy of large, extrusive complexes in continental rift basins of Northeast China:Analysis of general bedding patterns in volcanostratigraphy and their seismic reflection configurations

    Institute of Scientific and Technical Information of China (English)

    衣健; 王璞珺; 高有峰; 陈崇阳; 赵然磊

    2016-01-01

    The aim of this work is to establish volcanic seismic reflection configuration models in the rift basins of Northeast China from a new perspective, the volcanostratigraphic structure. Accordingly, the volcanostratigraphic structure of an outcrop near the Hailaier Rift Basin was analyzed to understand the characteristics and causal factors of physical boundaries. Further, 3D seismic reflection data and analysis of deep boreholes in the Songliao Rift Basin were used to establish the relationship between volcanic seismic reflection configurations and volcanostratigraphic structures. These studies suggested that in volcanic successions, physical boundaries coincide with volcanic boundaries, and their distributions are controlled by the stacking patterns of volcanic units. Therefore, volcanic seismic reflection configurations can be interpreted in terms of the stacking patterns of volcanic units. These are also referred to as general bedding patterns in volcanostratigraphy. Furthermore, four typical seismic reflection configurations were identified, namely, the chaotic, the parallel continuous, the hummocky, the multi-mound superimposed and the composite. The corresponding interpretation models comprised single massive unit, vertical, intersectional, lateral multi-mound, and composite stacking patterns. The hummocky and composite reflection configurations with intersectional and composite stacking patterns are the most favorable for the exploration of volcanic reservoirs in rift basins.

  19. Spatio-temporal patterns and factors controlling the hydrogeochemistry of the river Jhelum basin, Kashmir Himalaya.

    Science.gov (United States)

    Mir, Riyaz Ahmad; Jeelani, Gh; Dar, Farooq Ahmad

    2016-07-01

    River Jhelum is a major source of water for growing population and irrigation in the Kashmir Himalaya. The region is trending towards water scarcity as well as quality deterioration stage due to its highly unregulated development. The existence of few literature on various aspects of the basin prompts us to study the spatio-temporal variability of its physicochemical parameters and thereby to understand the regulating hydrogeochemical mechanisms based on 50 samples collected during high flow (June 2008) and low flow (January 2009) periods. The water chemistry exhibited significant spatial variability reflecting the mixing processes in the basin. The seasonal effect does change the concentration of ions significantly with modest variability in the order of ionic abundance. The Ca(2+) ion among cations and HCO3 (-) ion among anions dominate the ionic budget and correlates significantly with the diverse lithology of the basin. Three major water types, i.e., Ca-Mg-HCO3 (72 %), Ca-HCO3 (12 %), and Mg-Ca-HCO3 (16 %), suggest that the chemical composition of water is dominantly controlled by carbonate lithology, besides a significant contribution from silicates. However, at certain sites, the biological processes and anthropogenic activities play a major role. Relatively, the lower ionic concentration during high flow period (summer season) suggested the significant influence of higher discharge via dilution effect. The higher discharge due to higher rainfall and snow melting in response to rising temperature in this period leads to strong flushing of human and agricultural wastes into the river. The factor analysis also reflected the dominant control of varied lithology and anthropogenic sources on the water quality based on the four significant factors explaining collectively about 70-81 % of the total data variance. A two-member chloride mixing model used to estimate the discharge contribution of tributaries to the main river channel showed reliable results. It may

  20. Free-Living and Particle-Associated Bacterioplankton in Large Rivers of the Mississippi River Basin Demonstrate Biogeographic Patterns.

    Science.gov (United States)

    Jackson, Colin R; Millar, Justin J; Payne, Jason T; Ochs, Clifford A

    2014-12-01

    The different drainage basins of large rivers such as the Mississippi River represent interesting systems in which to study patterns in freshwater microbial biogeography. Spatial variability in bacterioplankton communities in six major rivers (the Upper Mississippi, Missouri, Illinois, Ohio, Tennessee, and Arkansas) of the Mississippi River Basin was characterized using Ion Torrent 16S rRNA amplicon sequencing. When all systems were combined, particle-associated (>3 μm) bacterial assemblages were found to be different from free-living bacterioplankton in terms of overall community structure, partly because of differences in the proportional abundance of sequences affiliated with major bacterial lineages (Alphaproteobacteria, Cyanobacteria, and Planctomycetes). Both particle-associated and free-living communities ordinated by river system, a pattern that was apparent even after rare sequences or those affiliated with Cyanobacteria were removed from the analyses. Ordination of samples by river system correlated with environmental characteristics of each river, such as nutrient status and turbidity. Communities in the Upper Mississippi and the Missouri and in the Ohio and the Tennessee, pairs of rivers that join each other, contained similar taxa in terms of presence-absence data but differed in the proportional abundance of major lineages. The most common sequence types detected in particle-associated communities were picocyanobacteria in the Synechococcus/Prochlorococcus/Cyanobium (Syn/Pro) clade, while free-living communities also contained a high proportion of LD12 (SAR11/Pelagibacter)-like Alphaproteobacteria. This research shows that while different tributaries of large river systems such as the Mississippi River harbor distinct bacterioplankton communities, there is also microhabitat variation such as that between free-living and particle-associated assemblages. PMID:25217018

  1. The Patagonian Orocline: New paleomagnetic data from the Andean magmatic arc in Tierra del Fuego, Chile

    Science.gov (United States)

    Cunningham, W. Dickson; Klepeis, Keith A.; Gose, Wulf A.; Dalziel, Ian W. D.

    1991-09-01

    The Hardy Formation is a 1300-m-thick succession of Upper Jurassic-Lower Cretaceous volcaniclastic sedimentary rocks interbedded with lava flows on Hoste Island at the southernmost tip of South America (55.5°S, 291.8°E). The strata are gently folded and metamorphosed to the prehnite-pumpellyite grade. A well-defined characteristic direction of magnetization, carried by magnetite, was readily identified in 95 samples from seven sites. At a given site, the directions group slightly better without structural correction. However, the means of the seven sites cluster better without tilt correction at the 99% significance level, implying that the magnetization postdates the folding event. It is most likely that the magnetization was acquired during the mid- to Late Cretaceous Andean orogeny that involved the folding and emplacement of the Patagonian Batholith. The fact that all samples are normally magnetized supports this age assignment. The pole position of 42.9°N, 156.6°E, α95=3.3° implies that the sampling area has rotated counterclockwise relative to cratonic South America by 90.1±11.9° with no significant flattening of inclination (F=1.9 ± 3.7°). Geologic considerations indicate that the rotation involved the entire Andean magmatic arc in Tierra Del Fuego. The results support interpretation of the Hardy Formation as part of the Andean magmatic arc deposited on the Pacific side of the Late Jurassic-Early Cretaceous Rocas Verdes marginal basin. Oroclinal bending of the arc in southernmost South America accompanied inversion of the marginal basin and the development of a Late Cretaceous-Cenozoic left-lateral transform system (South America-Antarctica) that later developed into the North Scotia Ridge.

  2. Evaluation criteria for uranium potential of sedimentary basins based on analysis of host sand body and structurally reworking pattern host sand body has been subject to

    International Nuclear Information System (INIS)

    On the basis of the introduction and the analysis of regional evaluation criteria for sandstone-type uranium deposits summarized by uranium geologists of USA and former Soviet Union, and by introducing new scientific progress in the field of sedimentology of clastic rocks, and basin geodynamics, main evaluation criteria composed of host sand body criterion and the criterion of structurally reworking pattern the host sand body has been subject to, are proposed, and the evaluation model based on analyzing the regional tectonic history and the evolution of prototype basin is set up. Finally, taking the Chaoshui basin as an example, the possibility for hosting epigenetic uranium mineralization in each horizon of the basin cover is discussed, then the main prospecting target horizon is discriminated, and potential ore-formation areas are proposed. (authors)

  3. Hydrological Responses of Andean Lakes and Tropical Floodplains to Climate Variability and Human Intervention: an Integrative Modelling Framework

    Science.gov (United States)

    Hoyos, I. C.; González Morales, C.; Serna López, J. P.; Duque, C. L.; Canon Barriga, J. E.; Dominguez, F.

    2013-12-01

    Andean water bodies in tropical regions are significantly influenced by fluctuations associated with climatic and anthropogenic drivers, which implies long term changes in mountain snow peaks, land covers and ecosystems, among others. Our work aims at providing an integrative framework to realistically assess the possible future of natural water bodies with different degrees of human intervention. We are studying in particular the evolution of three water bodies in Colombia: two Andean lakes and a floodplain wetland. These natural reservoirs represent the accumulated effect of hydrological processes in their respective basins, which exhibit different patterns of climate variability and distinct human intervention and environmental histories. Modelling the hydrological responses of these local water bodies to climate variability and human intervention require an understanding of the strong linkage between geophysical and social factors. From the geophysical perspective, the challenge is how to downscale global climate projections in the local context: complex orography and relative lack of data. To overcome this challenge we combine the correlational and physically based analysis of several sources of spatially distributed biophysical and meteorological information to accurately determine aspects such as moisture sources and sinks and past, present and future local precipitation and temperature regimes. From the social perspective, the challenge is how to adequately represent and incorporate into the models the likely response of social agents whose water-related interests are diverse and usually conflictive. To deal with the complexity of these systems we develop interaction matrices, which are useful tools to holistically discuss and represent each environment as a complex system. Our goal is to assess partially the uncertainties of the hydrological balances in these intervened water bodies we establish climate/social scenarios, using hybrid models that combine

  4. Distribution pattern and morphochemical relationships of manganese nodules from the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.; Miura, H.

    smooth and rough surfaces respectively) occur on almost all sediments, but in variable proportions. Thus, the overall distribution pattern shows that small nodules (less than 4-cm diameters) of lower grade (average value Ni + Cu + Co = 1.21%) with smooth...

  5. Delineating priority habitat areas for the conservation of Andean bears in northern Ecuador

    Science.gov (United States)

    Peralvo, M.F.; Cuesta, F.; Van Manen, F.

    2005-01-01

    We sought to identify priority areas for the conservation of Andean bear (Tremarctos ornatus) habitat in the northern portion of the eastern Andean cordillera in Ecuador. The study area included pa??ramo and montane forest habitats within the Antisana and Cayambe-Coca ecological reserves, and unprotected areas north of these reserves with elevations ranging from 1,800 to 4,300 m. We collected data on bear occurrence along 53 transects during 2000-01 in the Oyacachi River basin, an area of indigenous communities within the Cayambe-Coca Ecological Reserve. We used those data and a set of 7 environmental variables to predict suitability of Andean bear habitat using Mahalanobis distance, a multivariate measure of dissimilarity. The Mahalanobis distance values were classified into 5 classes of habitat suitability and generalized to a resolution of 1,650-m ?? 1,650-m grid cells. Clusters of grid cells with high suitability values were delineated from the generalized model and denned as important habitat areas (IHAs) for conservation. The IHAs were ranked using a weighted index that included factors of elevation range, influence from disturbed areas, and current conservation status. We identified 12 IHAs, which were mainly associated with pa??ramo and cloud forest habitats; 2 of these areas have high conservation priorities because they are outside existing reserves and close to areas of human pressure. The distribution of the IHAs highlighted the role of human land use as the main source of fragmentation of Andean bear habitat in this region, emphasizing the importance of preserving habitat connectivity to allow the seasonal movements among habitat types that we documented for this species. Furthermore, the existence of areas with high habitat suitability close to areas of intense human use indicates the importance of bear-human conflict management as a critical Andean bear conservation strategy. We suggest that a promising conservation opportunity for this species is

  6. Composition and sediment dispersal pattern of the Upper Triassic flysch in the eastern Himalayas, China: significance to provenance and basin analysis

    Science.gov (United States)

    Zhang, Chaokai; Li, Xianghui; Mattern, Frank; Zeng, Qinggao; Mao, Guozheng

    2016-05-01

    The paleogeography and basin type of Upper Triassic flysch (Langjiexue Group) in the eastern Himalayan Orogen are disputed. In order to shed new light on the flysch's origin, we applied different sedimentological methods. Assemblages of heavy minerals and clastic components of sandstones were utilized to determine the primary depositional composition. Heavy mineral indices, S/M ratios (thickness of sandstone + siltstone "S" versus slate/mudrock "M"), and paleocurrent data were combined to reveal the sediment dispersal pattern and the location of the source areas. In the analyzed sandstones, heavy minerals such as zircon, rutile, tourmaline, apatite, and anatase are most common, and zircon is predominant (most over 60 %). ZTR values range from 60 to 98 % and systematically increase southward. As a provenance-sensitive parameter, RuZi values vary in large magnitude and are significantly higher in both the east and west (>20 %) than in the center. The majority of S/M ratios decrease from north to south, suggesting an overall decrease in grain size to the south. Paleocurrent directions vary between 120° and 270° (main vector 205°, and 185° after 20° counterclockwise correction), displaying a radial-curved pattern. Variable heavy mineral assemblages indicate different sources, and the sandstones fall in the "recycled" and "mixed-arc orogeny" fields of Dickinson triplots, together supporting the view of multiple sources. Results of the ZTR values, S/M ratios, and paleocurrent directions illustrate a dispersal pattern, corresponding to a submarine fan system. The provenance and submarine fan dispersal pattern along with the basin configuration (deep basin with oceanic affinities) suggest that the Langjiexue Group accumulated in a remnant basin between Lhasa, Greater India, and Australia, where the sediments dispersed into the basin toward the developing orogen/suture zone and not away from the orogen, challenging the provenance direction for the traditional remnant

  7. Mercury Contamination in an Indicator Fish Species from Andean Amazonian Rivers Affected by Petroleum Extraction.

    Science.gov (United States)

    Webb, Jena; Coomes, Oliver T; Mainville, Nicolas; Mergler, Donna

    2015-09-01

    Elevated mercury (Hg) concentrations in fish from Amazonia have been associated with gold-mining, hydroelectric dams and deforestation but few studies consider the role of petroleum extraction. Hg levels were determined in fish samples collected in three river basins in Ecuador and Peru with contrasting petroleum exploitation and land-use characteristics. The non-migratory, piscivorous species, Hoplias malabaricus, was used as a bioindicator. The rate of Hg increase with body weight for this species was significantly higher on the Corrientes River, near the site of a recent oil spill, than on the other two rivers. In the absence of substantial deforestation and other anthropogenic sources in the Corrientes River basin, this finding suggests that oil contamination in Andean Amazonia may have a significant impact on Hg levels in fish. PMID:26205230

  8. Spatial and seasonal patterns in fish assemblage in Corrego Rico, upper Parana River basin

    Directory of Open Access Journals (Sweden)

    Erico L. H Takahashi

    2013-03-01

    Full Text Available The upper Paraná River basin drains areas of intensive industry and agriculture, suffering negative impacts. The Córrego Rico flows through sugar cane fields and receives urban wastewater. The aim of this work is to describe and to compare the fish assemblage structure in Córrego Rico. Six standardized bimonthly samples were collected between August 2008 and June 2009 in seven different stretches of Córrego Rico. Fishes were collected with an experimental seine and sieves, euthanized, fixed in formalin and preserved in ethanol for counting and identification. Data were recorded for water parameters, instream habitat and riparian features within each stretch. Non-metric multidimensional scaling, species richness and diversity analysis were performed to examine spatial and seasonal variation in assemblage structure. Fish assemblage structure was correlated with instream habitat and water parameters. The fish assemblage was divided in three groups: upper, middle and lower reaches. High values of richness and diversity were observed in the upper and lower stretches due to connectivity with a small lake and Mogi Guaçu River, respectively. Middle stretches showed low values of richness and diversity suggesting that a small dam in the middle stretch negatively impacts the fish assemblage. Seasonal differences in fish assemblage structure were observed only in the lower stretches.

  9. Vertical migration through faults and hydrocarbon accumulation patterns in deepwater areas of the Qiongdongnan Basin

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenfeng; LIU Zhen; CAO Shang; SUN Zhipeng; ZUO Qianmei; WANG Yahui; HE Weijun

    2014-01-01

    In the Qiongdongnan Basin, faults are well developed.Based on the drilling results, the traps controlled two or more faults are oil-rich. However, when only one fault cut through the sand body, there is no sign for hy-drocarbon accumulation in the sandstone. In terms of this phenomenon, the principle of reservoir-forming controlled by fault terrace is proposed, i.e., when the single fault activates, because of the incompressibility of pore water, the resistance of pore and the direction of buoyancy, it is impossible for hydrocarbon to ac-cumulate in sandstone. But when there are two or more faults, one of the faults acts as the spillway so the hydrocarbon could fill in the pore of sandstone through other faults. In total five gas bearing structures and four failure traps are considered, as examples to demonstrate our findings. According to this theory, it is well-advised that south steep slope zone of Baodao-Changchang Depression, south gentle slope zone of Lingshui Depression, north steep slope zone of Lingshui Depression, and north steep slope zone of Baodao Depression are the most favorable step-fault zones, which are the main exploration direction in next stage.

  10. Bransfield Basin and Cordilleran Orogenesis

    Science.gov (United States)

    Dalziel, I. W.; Austin, J. A.; Barker, D. H.; Christensen, G. L.

    2003-12-01

    Tectonic uplift of the Andean Cordillera was initiated in the mid-Cretaceous with inversion of a composite marginal basin along 7500 km of the continental margin of South America, from Peru to Tierra del Fuego and the North Scotia Ridge. In the southernmost Andes, from 50-56 degrees S, the quasi-oceanic floor of this basin is preserved in the obducted ophiolitic rocks of the Rocas Verdes (Green Rocks) basin. We suggest that the basin beneath Bransfield Strait, 61-64 degrees S, separating the South Shetland Islands from the Antarctic Peninsula, constitutes a modern analog for the Rocas Verdes basin. Marine geophysical studies of Bransfield basin have been undertaken over the past 12 years by the Institute for Geophysics, University of Texas at Austin, under the auspices of the Ocean Sciences Division and United States Antarctic Program, National Science Foundation. These studies have elucidated the structure and evolution of Bransfield basin for comparison with the Rocas Verdes basin, with a view to eventual forward modeling of the evolution of a hypothetical cordilleran orogen by compression and inversion of the basin. These are the processes that can be observed in the tectonic transformation of the Rocas Verdes basin into the southernmost Andean cordillera, as South America moved rapidly westward in an Atlantic-Indian ocean hot-spot reference frame during the mid-Cretaceous. Multi-channel reflection seismic data from the Bransfield basin reveal an asymmetric structural architecture characterized by steeply-dipping normal faults flanking the South Shetlands island arc and gently dipping listric normal faults along the Antarctic Peninsula margin. Normal fault polarity reversals appear to be related to distributed loci of magmatic activity within the basin. This architecture is remarkably similar to that deduced from field structural studies of the Rocas Verdes basin. Notably, the oceanward-dipping, low angle normal faults along the Antarctic Peninsula margin

  11. Potential effects of climate change on inundation patterns in the Amazon Basin

    Directory of Open Access Journals (Sweden)

    F. Langerwisch

    2013-06-01

    Full Text Available Floodplain forests, namely the Várzea and Igapó, cover an area of more than 97 000 km2. A key factor for their function and diversity is annual flooding. Increasing air temperature and higher precipitation variability caused by climate change are expected to shift the flooding regime during this century, and thereby impact floodplain ecosystems, their biodiversity and riverine ecosystem services. To assess the effects of climate change on the flooding regime, we use the Dynamic Global Vegetation and Hydrology Model LPJmL, enhanced by a scheme that realistically simulates monthly flooded area. Simulation results of discharge and inundation under contemporary conditions compare well against site-level measurements and observations. The changes of calculated inundation duration and area under climate change projections from 24 IPCC AR4 climate models differ regionally towards the end of the 21st century. In all, 70% of the 24 climate projections agree on an increase of flooded area in about one third of the basin. Inundation duration increases dramatically by on average three months in western and around one month in eastern Amazonia. The time of high- and low-water peak shifts by up to three months. Additionally, we find a decrease in the number of extremely dry years and in the probability of the occurrence of three consecutive extremely dry years. The total number of extremely wet years does not change drastically but the probability of three consecutive extremely wet years decreases by up to 30% in the east and increases by up to 25% in the west. These changes implicate significant shifts in regional vegetation and climate, and will dramatically alter carbon and water cycles.

  12. Quinoa trade in Andean countries: opportunities and challenges for family

    OpenAIRE

    Baudoin, Andrea; Lacroix, Pierril; Didier BAZILE; Chia, Eduardo

    2015-01-01

    Quinoa’s revival has roused much interest in Andean as well as in European and North American countries. This Andean product, formerly denigrated and destined only for self-consumption, has made its way into the diet of the urban populations of Andean countries and has now spread to the United States of America, Europe and other parts of the world. In the Andes, farmgate prices have gone up and the quinoa sector has become attractive to investors. A wide range of products based on this Chenop...

  13. Seed production differences of the Andean oak Quercus Humboldtii Bonpl. in two Andean forests of the Colombian Eastern Cordillera

    International Nuclear Information System (INIS)

    Knowledge of mechanisms of tree species reproduction under natural situations including fruit and seed production patterns is very important for forest management strategies. Considering the influence of abiotic factors such as soil characteristics, humidity and rainfall on fruiting phenology, we studied fruit production patterns of the Andean oak (Quercus humboldtii: Fagaceae) in two forest sites of the Colombian Eastern Cordillera (Cachalu and Patios Altos), under contrasting environmental conditions. At both sites, we monitored monthly fruit production of 15 trees in Cachalu and 11 in Patios Altos using fruit/seed traps placed under the tree crowns. In each site soil cores were extracted below the litter layer 20 cm depth, and soil characteristics and nutrients were analyzed. In general, trees in Cachalu produced more fruits than in Patios Altos, as well as mean fruit mass (wet and dry weight) was significantly higher in Cachalu. At both sites, oak fruiting peaked from April to May, when the highest rainfall occurs. We found positive correlations between fruit production and rainfall one month prior. High phosphorus (P) and potassium (K) were the main variables for explaining the high production. In contrast, high aluminum (Al) contents explained the low production found in Patios Altos. We discuss the importance of including fruit production for oak management strategies, such as restoration and reforestation programs.

  14. Deformation pattern around the conjoining strike-slip fault systems in the Basin and Range, southeast Nevada: The role of strike-slip faulting in basin formation and inversion

    Science.gov (United States)

    Çakir, Mehmet; Aydin, Atilla; Campagna, David J.

    1998-06-01

    Within the extensional regime of the Basin and Range, strike-slip faults create a regional pattern of opposing sense of fault systems. The relationship between these faults and other deformational features nearby is enigmatic. This paper addresses a diverse assemblage of contractional and extensional structures reflecting local uplift and subsidence, respectively, at the junction of two large Neogene strike-slip faults in southeastern Nevada, the right-lateral Las Vegas Valley shear zone and the left-lateral Bitter Spring Valley fault of the Lake Mead fault system. First, a middle Miocene lacustrine carbonate basin, the Bitter Ridge-Lovell Wash carbonate basin, formed north of the strike-slip faults. Second, the lacustrine basin inverted locally, while sediments accumulated south of the strike-slip faults. Third, the study area was deformed by north-northeast trending, high-angle oblique faults with normal and left-slip components. The results, both from field observations and numerical modeling of the intersecting strike-slip faults, show that the Las Vegas Valley shear zone and the Bitter Spring Valley fault may have produced the basin in the north and its intense contractional deformation as well as the southward shift of deposition during the inversion event. We conclude that conjoining strike-slip fault systems can promote localized vertical tectonics and lead to basin formation and uplift right next to each other. Subsequent inversion of the earlier basinal deposits, however, requires a reversal in the sense of slip across the Las Vegas Valley shear zone and a change in the regional stress system.

  15. Cenozoic foreland-basin evolution in the northern Andes : insights from thermochronology and basin analysis in the Eastern Cordillera, Colombia

    OpenAIRE

    Parra, Mauricio

    2009-01-01

    The modern foreland basin straddling the eastern margin of the Andean orogen is the prime example of a retro-arc foreland basin system adjacent to a subduction orogen. While widely studied in the central and southern Andes, the spatial and temporal evolution of the Cenozoic foreland basin system in the northern Andes has received considerably less attention. This is in part due to the complex geodynamic boundary conditions, such as the oblique subduction and accretion of the Caribbean plates ...

  16. Foreland sedimentary record of Andean mountain building during advancing and retreating subduction

    Science.gov (United States)

    Horton, Brian K.

    2016-04-01

    As in many ocean-continent (Andean-type) convergent margins, the South American foreland has long-lived (>50-100 Myr) sedimentary records spanning not only protracted crustal shortening, but also periods of neutral to extensional stress conditions. A regional synthesis of Andean basin histories is complemented by new results from the Mesozoic Neuquén basin system and succeeding Cenozoic foreland system of west-central Argentina (34-36°S) showing (1) a Late Cretaceous shift from backarc extension to retroarc contraction and (2) an anomalous mid-Cenozoic (~40-20 Ma) phase of sustained nondeposition. New detrital zircon U-Pb geochronological results from Jurassic through Neogene clastic deposits constrain exhumation of the evolving Andean magmatic arc, retroarc thrust belt, foreland basement uplifts, and distal eastern craton. Abrupt changes in sediment provenance and distal-to-proximal depositional conditions can be reconciled with a complex Mesozoic-Cenozoic history of extension, post-extensional thermal subsidence, punctuated tectonic inversion involving thick- and thin-skinned shortening, alternating phases of erosion and rapid accumulation, and overlapping igneous activity. U-Pb age distributions define the depositional ages of several Cenozoic stratigraphic units and reveal a major late middle Eocene-earliest Miocene (~40-20 Ma) hiatus in the Malargüe foreland basin. This boundary marks an abrupt shift in depositional conditions and sediment sources, from Paleocene-middle Eocene distal fluviolacustrine deposition of sediments from far western volcanic sources (Andean magmatic arc) and subordinate eastern cratonic basement (Permian-Triassic Choiyoi igneous complex) to Miocene-Quaternary proximal fluvial and alluvial-fan deposition of sediments recycled from emerging western sources (Malargüe fold-thrust belt) of Mesozoic basin fill originally derived from basement and magmatic arc sources. Neogene eastward advance of the fold-thrust belt involved thick

  17. The Andean Geotrail (2): An educational project

    Science.gov (United States)

    Galland, O.; Sassier, C.; Vial, M.; Thiberge, P.

    2009-12-01

    The role of Geosciences in our society is of primary importance. Its implications for humanity relate to major challenges such as climate change, managing energy resources, natural hazard mitigation, and water scarcity. Despite these issues being familiar to specialists, this is in general not the case for the public. In a world, where the impact of human activity is beginning to be seen on the environment, knowledge of the Earth and its history is paramount to make informed decisions that will influence our future. The necessity to educate the global population and raise awareness of Geosciences has led UNESCO to designate 2009 the International Year of the Planet Earth. In the framework of the UNESCO International Year of Planet Earth, we performed an educational project in collaboration with primary, secondary and high schools in France and Norway. Geosciences are not usually studied in schools, but this project allowed more than 600 pupils (from 17 schools) aged 8 to 18 years old to share the geological discoveries of our popular science adventure The Andean Geotrail (see Sassier et al., this session). The main educational goal was to promote Geosciences by illustrating in the field what geology is. Our natural laboratory was the spectacular Andean Cordillera. The secondary goal was to promote careers in geology and highlight their variety by allowing the pupils to meet geologists through portraits of geologists. The teachers of the partner schools used our project as a dynamic complement to their theoretical lessons. To set up this partnership, we obtained the support of the pedagogic supervisors of the French Ministry of National Education. The pedagogical project consisted of three steps: (1) Before the expedition (Oct.-Nov. 2008), we visited the pupils of each partner school to present the project, establish personal contact and engage the pupils in our adventure. (2) During The Andean Geotrail itself (Nov. 2008-Aug. 2009), we continuously documented our

  18. Andean Democracies: coming late to the party?

    Directory of Open Access Journals (Sweden)

    Marcelo Coutinho

    2007-01-01

    Full Text Available After a centuries-long history of oligarchical, populist, and authoritarian institutionality, in recent decades South America has begun the transition to a liberal democratic state model. This new state model harbors the contradiction of being both more democratic and less capable. In other words, it allows public participation and dissent but has less ability to respond, a role that has been largely transferred to the market, which has become globalized and more complex while experiencing difficulties in meeting social demands. The tension between democracy and economic limitations, combined with endogenous institutional problems, has sustained a climate of permanent political instability in parts of South America, reproducing fragmentations and conflicts, which are the focus of this study, a comparative analysis of five Andean countries: Bolivia, Peru, Ecuador, Colombia, and Venezuela.

  19. Andean flat subduction maintained by slab tunneling

    Science.gov (United States)

    Schepers, Gerben; van Hinsbergen, Douwe; Kosters, Martha; Boschman, Lydian; McQuarrie, Nadine; Spakman, Wim

    2016-04-01

    In two segments below the Andean mountain belt, the Nazca Plate is currently subducting sub-horizontally below South America over a distance of 200-300 km before the plate bends into the mantle. Such flat slab segments have pronounced effects on orogenesis and magmatism and are widely believed to be caused by the downgoing plate resisting subduction due to its local positive buoyancy. In contrast, here we show that flat slabs primarily result from a local resistance against rollback rather than against subduction. From a kinematic reconstruction of the Andean fold-thrust belt we determine up to ~390 km of shortening since ~50 Ma. During this time the South American Plate moved ~1400 km westward relative to the mantle, thus forcing ~1000 km of trench retreat. Importantly, since the 11-12 Ma onset of flat slab formation, ~1000 km of Nazca Plate subduction occurred, much more than the flat slab lengths, which leads to our main finding that the flat slabs, while being initiated by arrival of buoyant material at the trench, are primarily maintained by locally impeded rollback. We suggest that dynamic support of flat subduction comes from the formation of slab tunnels below segments with the most buoyant material. These tunnels trap mantle material until tearing of the tunnel wall provides an escape route. Fast subduction of this tear is followed by a continuous slab and the process can recur during ongoing rollback of the 7000 km wide Nazca slab at segments with the most buoyant subducting material, explaining the regional and transient character of flat slabs. Our study highlights the importance of studying subduction dynamics in absolute plate motion context.

  20. Tectonomagmatic Associations on the Central Andean Plateau

    Science.gov (United States)

    de Silva, S. L.; Viramonte, J. G.

    2012-12-01

    The Neogene evolution of the Central Andes is characterized by a strong association between plate convergence, mountain building and plateau formation, and magmatism. Plateau uplift by crustal shortening and thickening in the lower crust is broadly coincident with large scale silicic magmatism defined by the Neogene Central Andean ignimbrite province. Of particular interest here are the spatiotemporal correlations between silicic magmatism and tectonic evolution of the Altiplano-Puna plateau. Although magmatism is driven by the subduction-related flux from mantle to crust, the shift to "crustal" magmatism as indicated by elevated crustal isotopic indices after ~10Ma suggests a link between crustal thickening, plateau formation and silicic magmatism. In particular, elevated geotherms associated with crustal thickening and enhanced mantle flux associated with lithospheric delamination may have played a role in thermally preparing the Central Andean crust for enhanced silicic magma production during the extensive Neogene ignimbrite flare-up. Emplacement of these magmas in the upper crust throughout the Neogene may have fuelled a period of significant interaction between magmatism and tectonism on the plateau. With particular reference to the 21° to 24°S segment of the Central Andes, spatial and structural coincidence of calderas of the Altiplano Puna Volcanic Complex with the NW-SE striking Calama-Olacapata-El Toro fault zone suggests significant tectonomagmatic interaction. Location of calderas suggest that these regional faults focused magma intrusion and storage, while spatially and temporally correlated eruption pulses connote a tectonic control. Indeed, current thermomechanical models of magma chamber development and eruption triggering promote a role for external triggering of "perched" upper crustal magma chambers. This might have been achieved by melt-enhanced deformation, or alternatively, significant uplift (~1km) associated with the development of large

  1. Differences in nitrous oxide distribution patterns between the Bering Sea basin and Indian Sector of the Southern Ocean

    Institute of Scientific and Technical Information of China (English)

    CHEN Liqi; ZHANG Jiexia; ZHAN Liyang; LI Yuhong; SUN Heng

    2014-01-01

    Nitrous oxide (N2O) distribution patterns in the Bering Sea basin (BSB) and Indian Sector of the Southern Ocean (ISSO) were described and compared. In both sites, the waters were divided into four layers:surface layer, subsurface layer, N2O maximum layer, and deep water. Simulations were made to find out the most important factors that regulate the N2O distribution patterns in different layers of both sites. The results showed that in the surface water, N2O was more understaturated in the ISSO than the BSB. This phenom-enon in the surface water of ISSO may result from ice melt water intrusion and northeastward transport of the Antarctic surface water. Results of the rough estimation of air-sea fluxes during the expedition were (-0.34±0.07)-(-0.64±0.13) μmol/(m2·d) and (-1.47±0.42)-(-1.77±0.51) μmol/(m2·d) for the BSB and the ISSO, respectively. Strongly stratified surface layer and temperature minimum layer restricted exchange across the thermocline. The N2O maximum existed in higher concentration and deeper in the BSB than the ISSO, but their contribution to the upper layer by eddy diffusions was negligible. In deep waters, a concen-tration difference of 5 nmol/L N2O between these two sites was found, which suggested that N2O produc-tion occurred during thermohaline circulation. N2O may be a useful tracer to study important large-scale hydrographic processes.

  2. PATTERNS UTILIZED IN THE SIMULATION OF UNDERGROUND WATER FLOW AND THE TRANSPORTATION OF POLLUTANTS IN THE BAHLUI DRAINAGE BASIN

    Directory of Open Access Journals (Sweden)

    Ionut Minea

    2012-03-01

    Full Text Available ABSTRACT. – Patterns utilized in the simulation of underground water flow and the transportation of pollutants in the Bahlui drainage basin. In the actual context of accelerate economic development, the excessive exploatation of water resources from the underground and the contamination of these with different water pollutants has become a major problem which has enetered the attention of many researchers. For the evaluation of an underground water flow and pollutants transport sistem we have chosen the package of programs MODFLOW which includes a whole series of applications,such as MOC3D, MT3D, MT3DMS, PEST, UCODE, PMPATH, which allow simulations and multiple recalibrations of the capacity of recharging of the aquifers, the flowing of the water towards wells and drillings the transport of a pollutant agent in the underground or the evaluation of the exchange of water between the hidrographic network and aquifers. The sistem targets both the evaluation of the modelation of the underground flowing and the simulation of a punctual polluation of the canvas of groundwater scenery, in the meadow of the river Bahlui, west from Letcani village.

  3. Structural pattern of the Saïss basin and Tabular Middle Atlas in northern Morocco: Hydrological implications

    Science.gov (United States)

    Dauteuil, O.; Moreau, F.; Qarqori, K.

    2016-07-01

    The plain of Saïss is a fertile area of great agricultural production with major economic interests. Therefore, the improved knowledge about the water supply is imperative within a context of recurrent droughts and overexploitation of the groundwater. This plain is located in the Meknes-Fes basin and between two deformed domains: the Rif and Middle Atlas. The aquifers are fed by water coming from the Tabular Middle Atlas, for which the pathways are poorly constrained. This study provides new data to determine the water pathways based on a structural map produced from a novel analysis of SPOT images and a digital elevation model. This structural map reveals two fracture sets trending NE-SW and NW-SE. The first set is well known and corresponds to a main trend that controlled the tectonic and stratigraphic evolution of the study area. On the other hand, the NW-SE set was poorly described until now: it is both diffuse and widespread on the Tabular Middle Atlas. A comparison between the regional water flow trend, drainage pattern and structural map shows that the NW-SE fractures control the water flow from the Tabular Middle Atlas to the Saïss plain. A hydrological model is discussed where the water flow is confined onto Liassic carbonates and driven by NW-SE fractures. This study explains how a detailed structural mapping shows hydrology constraints.

  4. Analyzing the spatial patterns and drivers of ecosystem services in rapidly urbanizing Taihu Lake Basin of China

    Science.gov (United States)

    Ai, Junyong; Sun, Xiang; Feng, Lan; Li, Yangfan; Zhu, Xiaodong

    2015-09-01

    Quantifying and mapping the distribution patterns of ecosystem services can help to ascertain which services should be protected and where investments should be directed to improve synergies and reduce tradeoffs. Moreover, the indicators of urbanization that affect the provision of ecosystem services must be identified to determine which approach to adopt in formulating policies related to these services. This paper presents a case study that maps the distribution of multiple ecosystem services and analyzes the ways in which they interact. The relationship between the supply of ecosystem services and the socio-economic development in the Taihu Lake Basin of eastern China is also revealed. Results show a significant negative relationship between crop production and tourism income ( peffects of the urbanization process on providing and regulating services are also identified through a comparison of the ecosystem services in large and small cities. Regression analysis was used to compare and elucidate the relative significance of the selected urbanization factors to ecosystem services. The results indicate that urbanization level is the most substantial factor inversely correlated with crop production ( R 2 = 0.414) and nutrient retention services ( R 2 = 0.572). Population density is the most important factor that negatively affects carbon sequestration ( R 2 = 0.447). The findings of this study suggest the potential relevance of ecosystem service dynamics to urbanization management and decision making.

  5. An ontological approach to creating an Andean Weaving Knowledge Base

    OpenAIRE

    Brownlow, Richard; Capuzzi, Stefano; Helmer, Sven; Martins, Luciana; Normann, Immanuel; Poulovassilis, Alexandra

    2015-01-01

    Andean textiles are products of one of the richest, oldest and continuous weaving traditions in the world. Understanding the knowledge and practice of textile production as a form of cultural heritage is particularly relevant in the Andean context due to erosion of clothing traditions, reuse of traditional textiles on commodities targeted at the tourism market, and loss of knowledge embedded in textile production. ``Weaving Communities of Practice'' was a pilot project that aimed to create a ...

  6. The new Andean Regional Office of Astronomy for Development (ROAD)

    Science.gov (United States)

    Char, Farid; Forero-Romero, Jaime

    2015-08-01

    The Andean Regional Office of Astronomy for Development (ROAD) is a new effort in South America to serve several goals in astronomical development. Six countries (Bolivia, Colombia, Chile, Ecuador, Perú and Venezuela) will work together, representing a common language block in the Andean region and focusing on develop strategies to strengthen the professional research, education and popularization of astronomy. Our current Working Structure comprises a ROAD Coordinator and Coordinators per Task Force, as well as Organizing Committees, Collaborators and Volunteers.The participating institutions of this new ROAD have been involved in many projects involving each of the current OAD’s Task Forces: research, schools and children and public, exploring educational activities/material to be shared among the Andean countries, standardizing the knowledge and creating inspirational experiences. We expect to generate many efforts in order to bring a more homogeneous activity in each Andean country, taking into account the special role of Chile in global astronomy, due to its great conditions for astronomy and the involvement of many professional observatories, universities and astronomy institutions.Our current (and upcoming) most relevant activities includes: Andean Schools on Astronomy, Andean Graduate Program and Massive Open Online Courses (TF1); Virtual Training Sessions and Teaching material for the visually impaired students; Annual TF2 meeting to gather all the collaborators (TF2); Development for planetariums and Communicating Astronomy with the Public (TF3). The Andean region, in the other hand, will also be involved in at least two important events: the CAP Meeting in May 2016 and the XV LARIM in October 2016 (both in Colombia); and Chile will bid to host the XXXI IAU GA in 2021, with the aim of show the great advances in astronomical development from the Andean region and South America.

  7. Modelling of INTER-Linkages Between LAND Cover Pattern and Socio-Economic Factors in the Idemili River Basin of South Eastern Nigeria

    Science.gov (United States)

    Maduekwe, N. I.; Adesina, F. A.

    2014-12-01

    This study explores the inter-relationships between socio-economic factors and land cover pattern in the Idemili River Basin of South Eastern Nigeria. It is based on the concept of coupled human environment systems and focuses on the modelling of community scale relationships between critical land cover parameter and socio-demographic, economic and cultural factors in the basin. The modelling was implemented with pixel level NDVI indicators of vegetation cover density developed from NigeriaSat image with 32m resolution linked to eight indicators of socio-economic factors developed from a household survey of the basin. NDVI and socio-economic data were matched for 25 sampled localities in the basin and their relationships modelled with correlation, regression and Principal Component Analysis statistics. NDVI based image analysis showed a high level of human impact on vegetation. The Model output shows that bivariate relationships between vegetation cover dynamics and socio-demographic variables were the most significant, with R Square values > 0.60 for linear and non linear models. Vegetation cover density has high inverse correlations with population, urbanization levels and number of households in localities. Population/urbanization status of localities was also the most significant Principal Component or underlying dimension linked to spatial dynamics of vegetation cover in the basin accounting for 50% of factor variations. Relationships between vegetation cover densities and economic factors (occupational and household energy patterns) and socio-cultural factors (environmental knowledge, values and governance) were weaker and less significant. The study captured the linkages between landcover- represented by vegetation cover- and socio-economic parameters. It demonstrates that socio-economic factors are major drivers of change in the basin. Key Words: Socio-economic factors, Vegetation Cover, NDVI, Socio-ecological Systems, State Variables, South Eastern Nigeria

  8. Patterns of Precipitation and Convection Occurrence over the Mediterranean Basin Derived from a Decade of Microwave Satellite Observations

    Directory of Open Access Journals (Sweden)

    Bahjat Alhammoud

    2014-05-01

    Full Text Available The Mediterranean region is characterized by its vulnerability to changes in the water cycle, with the impact of global warming on the water resources being one of the major concerns in social, economical and scientific ambits. Even if precipitation is the best-known term of the Mediterranean water budget, large uncertainties remain due to the lack of suitable offshore observational data. In this study, we use the data provided by the Advanced Microwave Sounding Unit-B (AMSU-B on board NOAA satellites to detect and analyze precipitating and convective events over the last decade at spatial resolution of 0.2° latitude × 0.2° longitude. AMSU-B observation shows that rain occurrence is widespread over the Mediterranean in wintertime while reduced in the eastern part of the basin in summer. Both precipitation and convection occurrences display a weak diurnal cycle over sea. In addition, convection occurrences, which are essentially located over land during summertime, shift to mostly over the sea during autumn with maxima in the Ionian sub-basin and the Adriatic Sea. Precipitation occurrence is also inferred over the sea from two other widely used climatological datasets, HOAPS (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data and the European Centre for Medium-Range Weather Forecasts (ECMWF reanalysis interim (ERA-Interim. There is generally a rather fair agreement between these climatologies for describing the large-scale patterns such as the strong latitudinal gradient of rain and eastward rain signal propagation. Furthermore, the higher spatial resolution of AMSU-B measurements (16 km at nadir gives access to mesoscale details in the region (e.g., coastal areas. AMSU-B measurements show less rain occurrences than HOAPS during wintertime, thereby suggesting that some of the thresholds used in our method might be too stringent during this season. We also observed that convection occurrences in ERA-Interim are systematically

  9. Integration of hydrologic and water allocation models in basin-scale water resources management considering crop pattern and climate change: Karkheh River Basin in Iran

    Science.gov (United States)

    The paradigm of integrated water resources management requires coupled analysis of hydrology and water resources in a river basin. Population growth and uncertainties due to climate change make historic data not a reliable source of information for future planning of water resources, hence necessit...

  10. Review of the andean armored catfishes of the genus Dolichancistrus Isbrücker (Siluriformes: Loricariidae

    Directory of Open Access Journals (Sweden)

    Gustavo A. Ballen

    2012-09-01

    Full Text Available The loricariid catfish genus Dolichancistrus is reviewed and four species recognized. Species of Dolichancistrus are distinguished from each other by the degree of development of the pectoral-fin spine, the form of the distal margin of the pelvic fin, the relative size and form of the cheek plates, the pattern of odontodes along the margin of the snout, the presence versus absence of a buccal papilla at the premaxillary symphysis, and the relative lengths of the anal- versus pelvic-spines. Dolichancistrus atratoensis is known from the río Atrato system and the río Cubarradó on the Pacific versant of Colombia; D. carnegiei occurs in the eastern río Magdalena basin in the departments of Boyacá and Santander, Colombia; D. cobrensis inhabits southern tributaries of the Lago Maracaibo basin in Colombia and Venezuela along with some highland rivers of the Cordillera de Mérida in Venezuela draining into the río Orinoco system; and D. fuesslii is known from the Andean piedmont portions of the río Meta basin in the western río Orinoco system. Pseudancistrus pediculatus is considered a junior synonym of Ancistrus fuesslii. Chaetostomus setosus previously assigned to Dolichancistrus, was found to lack features characteristic of its putative congeners and is rather more closely related to other members of Chaetostoma group. Consequently, the species is herein considered as incertae sedis within that group. Dolichancistrus is diagnosed, a key is provided to the members of the genus, and diagnoses and redescriptions are provided for all of the recognized species.Se presenta una revisión del género Dolichancistrus y se reconocen cuatro especies válidas. Las especies de Dolichancistrus se distinguen entre sí a partir del grado de desarrollo de la espina pectoral, la forma del margen distal de la aleta pélvica, el tamaño relativo y la forma de las placas operculares, el patrón de odontoides a lo largo del margen del hocico, la presencia versus

  11. Using Pooled Local Expert Opinions (PLEO) to Discern Patterns in Sightings of Live and Dead Manatees (Trichechus senegalensis, Link 1785) in Lower Sanaga Basin, Cameroon

    OpenAIRE

    Mayaka, Theodore B.; Takoukam Kamla, Aristide; Self-Sullivan, Caryn

    2015-01-01

    We aimed at unveiling patterns in live and dead manatee sightings in the Lower Sanaga Basin, Cameroon. For this purpose, the expert opinions of 133 local fishers were collected during in-person interviews, distilled using categorical data analysis, and checked against scientific literature. The five main results are as follows: manatees were sighted averagely once a week in lakes, rivers, and the coast & estuaries, mostly in group sizes of 2-3; the odds of sighting live manatees (respectively...

  12. The Andean Geotrail (1): A scientific adventure

    Science.gov (United States)

    Sassier, C.; Galland, O.; Raufaste, C.; Mair, K.

    2009-12-01

    The role of Geosciences in our society is of primary importance. Its implications for humanity relate to major challenges such as climate change, managing energy resources, natural hazard mitigation, and water scarcity. Despite these issues being familiar to specialists, this is in general not the case for the public. In a world, where the impact of human activity is beginning to be seen on the environment, knowledge of the Earth and its history is paramount to make informed decisions that will influence our future. The necessity to educate the global population and raise awareness of Geosciences has led UNESCO to designate 2009 the International Year of the Planet Earth. In this context and with the label of the UNESCO, we organized and performed a popular science adventure that was followed in real time by both school children and many adults around the world. The Andean Geotrail consisted of a cycling expedition through a spectacular geological environment, the Andean Cordillera. During the nine month expedition, we cycled 8000 km and walked 400 km from Ushuaia in the Southern tip of Argentina to Nazca in Peru to encounter a rich variety of geological environments: active volcanoes, earthquakes, mineral and hydrocarbon deposits, and fantastic geological scenery. All this makes the Andes a great pedagogical natural laboratory. During the expedition, we visited spectacular geological localities that illustrate key Earth Science phenomena (such as mines and hydrocarbon deposits, erupting volcanoes and seismogenically active areas, and national parks) and discovered their implications for the local people. Along the way, we interviewed local geologists and scientists who helped us understand the geology of their areas. We gathered our own observations with those of the local specialists and published essays, articles and photographs on our website and blog (www.georouteandine.fr/English, http://georouteandine.blogspot.com). Seventeen schools in France and Norway

  13. Spatial and Temporal Patterns in Fish Assemblages Following an Artificially Extended Floodplain Inundation Event, Northern Murray-Darling Basin, Australia

    Science.gov (United States)

    Rolls, Robert J.; Wilson, G. Glenn

    2010-04-01

    Water extraction from dryland rivers is often associated with declines in the health of river and floodplain ecosystems due to reduced flooding frequency and extent of floodplain inundation. Following moderate flooding in early 2008 in the Narran River, Murray-Darling Basin, Australia, 10,423 ML of water was purchased from agricultural water users and delivered to the river to prolong inundation of its terminal lake system to improve the recruitment success of colonial waterbirds that had started breeding in response to the initial flooding. This study examined the spatial and temporal patterns of fish assemblages in river and floodplain habitats over eight months following flooding to assess the possible ecological benefits of flood extension. Although the abundances of most fish species were greater in river channel habitats, the fish assemblage used floodplain habitats when inundated. Young-of-the-year (4-12 months age) golden perch ( Macquaria ambigua) and bony bream ( Nematalosa erebi) were consistently sampled in floodplain sites when inundated, suggesting that the floodplain provides rearing habitat for these species. Significant differences in the abundances of fish populations between reaches upstream and downstream of a weir in the main river channel indicates that the effectiveness of the environmental water release was limited by restricted connectivity within the broader catchment. Although the seasonal timing of flood extension may have coincided with sub-optimal primary production, the use of the environmental water purchase is likely to have promoted recruitment of fish populations by providing greater access to floodplain nursery habitats, thereby improving the ability to persist during years of little or no flow.

  14. Two new Cystoderma species from high Andean Ecuador

    DEFF Research Database (Denmark)

    Saar, I.; Læssøe, Thomas

    2006-01-01

    ABSTRACT: Two new agaric species, Cystoderma andinum and C. papallactae are described from high Andean Ecuador.......ABSTRACT: Two new agaric species, Cystoderma andinum and C. papallactae are described from high Andean Ecuador....

  15. Architecture of the Northwest Andean Microplates

    Science.gov (United States)

    Potts, L. V.; Hernandez, O.; von Frese, R. R.; Schmidt, M.

    2005-05-01

    Recently revised models on global plate boundary zones show that the North Andes microplate includes a wide distribution of seismicity, volcanic events, active faulting and extreme topography. The current description of the north Andean microplate boundaries is interpreted from a variety of geological and geophysical models including volcanism and seismicity with variable confidence levels. The poorly understood complex structure and geometry of plate boundaries limits the ability of current physical models to predict neotectonic and other effects including intra-plate lithospheric stresses and strain. Together with local surface gravity and topography data, a variety of available space geodetic sensors have substantially improved the modeling of the lithosphere for analyzing subsurface mass dynamics. They include the GPS-derived 3-D crustal velocities, high resolution (90-m) topography, seismic surveys and high resolution gravity models derived from integrated satellite (e.g., CHAMP and GRACE, 200-km resolution) and terrestrial observations (up to ~5 km resolution). Spherical wavelets is a modern tool for a multi-resolution representation of spatially heterogenously distributed gravity (consistent with the generalized boundary value problem) and for topography datasets with the distinct ability to enhance localized signals. Analysis of multi-resolution gravity and topography models combined with GPS velocities provide a unique opportunity to characterize the structure, isostatic conditions, mass dynamics, and intra-plate deformations of the North Andes microplate.

  16. Andean tectonics: Implications for Satellite Geodesy

    Science.gov (United States)

    Allenby, R. J.

    1984-09-01

    Current knowledge and theories of large scale Andean tectonics as they relate to site planning for the NASA Crustal Dynamics Program's proposed high precision geodetic measurements of relative motions between the Nazca and South American plates are summarized. The Nazca Plate and its eastern margin, the Peru-Chile Trench, is considered a prototype plate marked by rapid motion, strong seismicity and well defined boundaries. Tectonic activity across the Andes results from the Nazca Plate subducting under the South American plate in a series of discrete platelets with different widths and dip angles. This in turn, is reflected in the tectonic complexity of the Andes which are a multitutde of orogenic belts superimposed on each other since the Precambrian. Sites for Crustal Dynamics Program measurements are being located to investigate both interplate and extraplate motions. Observing operations have already been initiated at Arequipa, Peru and Easter Island, Santiago and Cerro Tololo, Chile. Sites under consideration include Iquique, Chile; Oruro and Santa Cruz, Bolivia; Cuzco, Lima, Huancayo and Bayovar, Peru; and Quito and the Galapagos Islands, Ecuador. Based on scientific considerations, Santa Cruz, Huancayo (or Lima), Quito and the Galapagos Islands should be replaced by Isla San Felix, Chile; Brazilia or Petrolina, Brazil; and Guayaquil, Ecuador. If resources permit, additional important sites would be Buenaventura and Villavicencio or Puerto La Concordia, Colombia; and Mendoza and Cordoba, Argentina.

  17. How to Deepen the Dialogue between the Andean Community and the EU

    OpenAIRE

    Sheila Page

    2007-01-01

    This paper discusses the European Union trade policy making process and implications for the Andean community. The European Union (EU) divides its agreements with other countries into three types: neighbourhood, trade and development, and is currently classifying the negotiations with the Andean Community as development. The Andean Community must examine how the EU has approached its agreements in the past and what the Andean countries need from an agreement, and decide whether it wants to ne...

  18. Phlebotomine sandflies (Diptera: Psychodidae in a sub-Andean forest from the Norte de Santander, Colombia

    Directory of Open Access Journals (Sweden)

    Richard Hoyos-López

    2016-01-01

    Full Text Available Background & objectives: The recognition of communities of arthropods with medical importance in natural systems constitutes an important step in the prediction of possible epidemic events and/or emergence of infectious diseases in the human population. This is due to anthropogenic impact in natural areas and landscape modification, which changes the dynamics of pathogenic agents, reservoirs, and vector insects. In this study, an inventory was compiled of species of the genus Lutzomyia present in sub-Andean forest from the confluence of the Pamplonita River basin. Methods: CDC-light and Shannon traps were used for collecting adult phlebotomine sandflies during the month of October 2013 in a sub-Andean forest from river basin Pamplonita. All specimens were identified using morphological keys. The epidemiological relevance of each species was reported using a literature review about natural infection or vector incrimination with Leishmania species or other pathogens microorganism. Results: A total of 2755 specimens belonging to eight species of the genus Lutzomyia were collected. Out of the eight species, seven belonged to the group verrucarum (Lutzomyia sp - townsendi series, L. ovallesi, L. spinicrassa, L. serrana, L. townsendi, L. nuneztovari and L. pia, while one belonged to the subgenus Helcocyrtomyia (L. hartmanni. A new registry of L. townsendi was observed for the Norte de Santander department. Interpretation & conclusion: The appreciable diversity of the verrucarum group observed in this area suggest further investigation on the biogeography and evolution of this group, and epidemiological risk for human populations around this area, as there are reports of Leishmania natural infection and favourable conditions for domestication of phlebotomines in rural towns.

  19. Water-scarcity patterns : spatiotemporal interdependencies between water use and water availability in a semi-arid river basin

    OpenAIRE

    Oel, van, C.J.

    2009-01-01

    This thesis addresses the interdependencies between water use and water availability and describes a model that has been developed to improve understanding of the processes that drive changes and variations in the spatial and temporal distribution of water resources in a semi-arid river basin. These processes include hydrological processes and water user responses to variations and changes in water availability. The results are relevant for climate change impact assessments and river basin ma...

  20. Landscape genetics, historical isolation and cross-Andean gene flow in the wax palm, Ceroxylon echinulatum (Arecaceae)

    DEFF Research Database (Denmark)

    Trénel, P.; Hansen, Michael Møller; Nordmand, S.; Borchsenius, F.

    2008-01-01

    landscape genetics of the Andean wax palm Ceroxylon echinulatum (Arecaceae) that occurs in two narrow bands of montane forests on each side of the Andes in Ecuador and northeastern Peru. First, we tested the hypothesis of C. echinulatum being a geographic cline species crossing the Andes in the Amotape......-Huancabamba zone (AHZ) of southern Ecuador/northern Peru, as indicated by observations on fruit morphology. Second, we assessed the timeframe of cross-Andean divergence, and third, we investigated the impact of contemporary and historical landscape features on observed spatio-genetic patterns. Individual......-based Bayesian clustering (BC) identified a northeastern, southeastern, southwestern, and northwestern cluster, with areas of genetic discontinuity coinciding with the Andes and the Giron-Paute deflection. F-statistics derived from BC suggested an east-to-west dispersal history. Population-based analyses...

  1. On the Nature of Cross-Linguistic Transfer: A Case Study of Andean Spanish

    Science.gov (United States)

    Muntendam, Antje G.

    2013-01-01

    This paper presents the results of a study on cross-linguistic transfer in Andean Spanish word order. In Andean Spanish the object appears in preverbal position more frequently than in non-Andean Spanish, which has been attributed to an influence from Quechua (a Subject-Object-Verb language). The high frequency of preverbal objects could be…

  2. Explaining Andean potato weevils in relation to local and landscape features: a facilitated ecoinformatics approach.

    Directory of Open Access Journals (Sweden)

    Soroush Parsa

    Full Text Available BACKGROUND: Pest impact on an agricultural field is jointly influenced by local and landscape features. Rarely, however, are these features studied together. The present study applies a "facilitated ecoinformatics" approach to jointly screen many local and landscape features of suspected importance to Andean potato weevils (Premnotrypes spp., the most serious pests of potatoes in the high Andes. METHODOLOGY/PRINCIPAL FINDINGS: We generated a comprehensive list of predictors of weevil damage, including both local and landscape features deemed important by farmers and researchers. To test their importance, we assembled an observational dataset measuring these features across 138 randomly-selected potato fields in Huancavelica, Peru. Data for local features were generated primarily by participating farmers who were trained to maintain records of their management operations. An information theoretic approach to modeling the data resulted in 131,071 models, the best of which explained 40.2-46.4% of the observed variance in infestations. The best model considering both local and landscape features strongly outperformed the best models considering them in isolation. Multi-model inferences confirmed many, but not all of the expected patterns, and suggested gaps in local knowledge for Andean potato weevils. The most important predictors were the field's perimeter-to-area ratio, the number of nearby potato storage units, the amount of potatoes planted in close proximity to the field, and the number of insecticide treatments made early in the season. CONCLUSIONS/SIGNIFICANCE: Results underscored the need to refine the timing of insecticide applications and to explore adjustments in potato hilling as potential control tactics for Andean weevils. We believe our study illustrates the potential of ecoinformatics research to help streamline IPM learning in agricultural learning collaboratives.

  3. Three-dimensional approach to understanding the relationship between the Plio–Quaternary stress field and tectonic inversion in the Triassic Cuyo Basin, Argentina

    Directory of Open Access Journals (Sweden)

    L. Giambiagi

    2015-06-01

    Full Text Available The Cacheuta sub-basin of the Triassic Cuyo Basin is an example of rift basin inversion contemporaneous to the advance of the Andean thrust front, during the Plio–Quaternary. This basin is one of the most important sedimentary basins in a much larger Triassic NNW-trending depositional system along the southwestern margin of the Pangea supercontinent. The amount and structural style of inversion is provided in this paper by a three-dimensional approach to the relationship between inversion of rift-related structures and spatial variations in late Cenozoic stress fields. The Plio–Quaternary stress field exhibits important N–S variations in the foreland area of the southern Central Andes, between 33 and 34° S, with a southward gradual change from pure compression, with σ1 and σ2 being horizontal, to a strike-slip type stress field, with σ2 being vertical. We present a 3-D approach for studying the tectonic inversion of the sub-basin master fault associated with strike-slip–reverse to strike-slip faulting stress regimes. We suggest that the inversion of Triassic extensional structures, striking NNW to WNW, occurred during the Plio–Pleistocene in those areas with strike-slip–reverse to strike-slip faulting stress regime, while in the reverse faulting stress regime domain they remain fossilized. Our example demonstrates the impact of the stress regime on the reactivation pattern along the faults.

  4. Carotenoid composition and vitamin A value in ají (Capsicum baccatum L.) and rocoto (C. pubescens R. & P.), 2 pepper species from the Andean region.

    Science.gov (United States)

    Rodríguez-Burruezo, Adrián; González-Mas, Maria del Carmen; Nuez, Fernando

    2010-10-01

    The carotenoid patterns of fully ripe fruits from 12 Bolivian accessions of the Andean peppers Capsicum baccatum (ají) and C. pubescens (rocoto) were determined by high-performance liquid chromatography (HPLC)-photodiode array detector (PDA)-mass spectrometry (MS). We include 2 California Wonder cultivars as C. annuum controls. A total of 16 carotenoids were identified and differences among species were mostly found at the quantitative level. Among red-fruited genotypes, capsanthin was the main carotenoid in the 3 species (25% to 50% contribution to carotenoid fraction), although ajíes contained the lowest contribution of this carotenoid. In addition, the contribution of capsanthin 5,6-epoxide to total carotenoids in this species was high (11% to 27%) in comparison to rocotos and red C. annuum. Antheraxanthin and violaxanthin were, in general, the next most relevant carotenoids in the red Andean peppers (6.1% to 10.6%). Violaxanthin was the major carotenoid in yellow-/orange-fruited genotypes of the 3 species (37% to 68% total carotenoids), although yellow rocotos were characterized by lower levels (Capsicum peppers are known for their content in carotenoids, although there is no information about 2 species with Andean origin: ajíes and rocotos. Due to their relevance for the Andean cuisine and increasing importance in ethnic restaurants in Europe, we studied their carotenoid pattern and vitamin A contribution. PMID:21535519

  5. Rapid hydrological response to central Andean Plateau uplift, NW-Argentina

    Science.gov (United States)

    Rohrmann, Alexander; Sachse, Dirk; Strecker, Manfred R.; Mulch, Andreas; Pingel, Heiko; Alonso, Ricardo N.

    2015-04-01

    The response of the regional and global hydrological cycle, vegetation and erosion to tectonic surface uplift and topographic growth of the world's largest orogenic plateaus and their flanking ranges is subject to ongoing debate. During the last decade reconstructions of paleo-environmental conditions and the topographic evolution of mountain belts have increasingly relied on stable isotope proxies retaining the oxygen (δ18O) or hydrogen (δD) isotopic composition of ancient meteoric waters or carbon (δ13C) of vegetation. Intermontane basin sediments along the Puna of NW Argentina, the southern extension of the Altiplano-Puna Plateau and the world's second largest plateau, record the eastward-directed lateral growth of the central Andes and the spatiotemporal impact of tectonism on hydrologic, sedimentary, and ecological changes through time. Here we reconstructed paleo-hydrological changes during a phase of major Andean uplift and orographic barrier formation (10-2 Ma) along the eastern flank of the Puna Plateau from a sedimentary sequence within the intermontane Angastaco basin of NW Argentina (25°45 S, 66 W). We use a unique array of stable water-isotope proxies in leafwaxes, pedogenic carbonates and hydrated volcanic glass. In addition we use vegetation-cover proxies based on stable C isotopes obtained from leaf-waxes and pedogenic carbonates. Lipid biomarker leafwax δD values range between -95 and -160 ‰ (VSMOW), and δ13C values from -23 to -36 ‰ (PDB). Pedogenic carbonate δ18O values range from 18 to 31 ‰ (VSMOW) and δ13C values vary between -4 to -17 ‰ (PDB), whereas volcanic glass δD values range from -71 to -95 ‰ (VSMOW). In combination, these proxies provide a precipitation - evapotranspiration record, which reveals the onset of the South American Low Level-Jet in NW Argentina at ~ 9 Ma and the presence of seasonally humid foreland conditions until 7 Ma, followed by orographic barrier formation upwind of the basin and rapid creation of

  6. Aeromagnetic anomaly patterns reveal buried faults along the eastern margin of the Wilkes Subglacial Basin (East Antarctica)

    Science.gov (United States)

    Armadillo, E.; Ferraccioli, F.; Zunino, A.; Bozzo, E.

    2007-01-01

    The Wilkes Subglacial Basin (WSB) is the major morphological feature recognized in the hinterland of the Transantarctic Mountains. The origin of this basin remains contentious and relatively poorly understood due to the lack of extensive geophysical exploration. We present a new aeromagnetic anomaly map over the transition between the Transantarctic Mountains and the WSB for an area adjacent to northern Victoria Land. The aeromagnetic map reveals the existence of subglacial faults along the eastern margin of the WSB. These inferred faults connect previously proposed fault zones over Oates Land with those mapped along the Ross Sea Coast. Specifically, we suggest a link between the Matusevich Frature Zone and the Priestley Fault during the Cenozoic. The new evidence for structural control on the eastern margin of the WSB implies that a purely flexural origin for the basin is unlikely.

  7. Molecular data reveal spatial and temporal patterns of diversification and a cryptic new species of lowland Stenocercus Duméril & Bibron, 1837 (Squamata: Tropiduridae).

    Science.gov (United States)

    Teixeira, Mauro; Prates, Ivan; Nisa, Carolina; Silva-Martins, Nathalia Suzan Camarão; Strüssmann, Christine; Rodrigues, Miguel Trefaut

    2016-01-01

    Phylogenetic studies have uncovered biogeographic patterns and the associated diversification processes of Neotropical wet forest taxa, yet the extensive open and drier biomes have received much less attention. In the Stenocercus lizard radiation, restricted sampling and phylogenetic information have limited inferences about the timing, spatial context, and environmental drivers of diversification in the open and dry lowland settings of eastern and southern South America. Based on new DNA sequence data of previously unsampled species, we provide an updated historical biogeographic hypothesis of Stenocercus. We infer phylogenetic relationships, estimate divergence times, and track ancestral distributions, asking whether cladogenetic events within the genus correlate to reported shifts in South American landscapes during the past 30millionyears, focusing in the open and drier areas. To examine correlations between genetic and ecological divergence, we extracted environmental data from occurrence records and estimated climatic envelopes occupied by lowland taxa. Our results suggest that Stenocercus began to diversify around the South American Midwest by the late Oligocene. We recovered two main lowland and two main Andean clades within the genus; within both Andean clades, most cladogenetic events date back to the Miocene, synchronously with the most intense phase of Andean uplift. In the western clade of lowland Stenocercus, species ranges and divergence times are consistent with major landscape shifts at the upper Guaporé and Paraguay River basins as a result of Andean orogeny, suggesting vicariant speciation. By contrast, in the 'horned' lowland clade, we find evidence that dispersal and ecological differentiation have shaped species divergences and current ranges in the Brazilian Cerrado, Caatinga, Pampas and Atlantic Forest, possibly under a vanishing refuge scenario. Lastly, our phylogenetic results indicate two divergent clades within the formerly recognized

  8. Wind tunnel experiments of air flow patterns over nabkhas modeled after those from the Hotan River basin,Xinjiang,China(Ⅱ):vegetated

    Institute of Scientific and Technical Information of China (English)

    Zhizhong LI; Rong MA; ShengLi WU; Janis DALE; Lin GE; Mudan HE; Xiaofeng WANG; Jianhui JIN; Jinwei LIU; Wanjuan LI

    2008-01-01

    This paper examines the results of wind tunnel experiments on models of nabkha,based on those studied in the Hotan River basin.Semi-spherical and conical models of nabkhas were constructed at a ratio of 40:1 in light of the on-site observation.Artificial vegetation of simulated Tamarix spp.was put on top of each model.Parameters of the shape,including height,width,and diameter of vegetated semi-spherical and conical nabkha.were measured in the Hotan River basin.Wind tunnel experiments on the semi-spherical and conical nabkha used clean air devoid of additional sediments at five different wind speeds (6-14 m/s)to study the influence of vegetation on airflow patterns.Results of the experiments indicate that vegetation at the top of the nabkhas enhances the surface roughness of the sand mounds,retards airflow over the sand mounds,reduces airflow energy,eliminates erosional pits occurring on the top surface of non-vegetated sand mounds and enhances the range of influence of the vortex that forms on the leeward slope.Vegetation changes the airflow pattern upwind and downwind of the sand mound and reduces the transport of sand away from the nabkha.This entrapment of sediment by the vegetation plays an important role in sustaining the nabkha landscape of the study area.The existence of vegetation makes fine materials in wind-sand flow to possibly deposit,and promotes nabkha formation.The imitative flow patterns Of different morphological nabkhas have also been verified by on-site observation in the river basin.

  9. Species richness and indices of abundance of medium-sized mammals in andean forest and reforestations with andean alder: a preliminary analysis

    OpenAIRE

    Sánchez, Francisco; SÁNCHEZ-PALOMINO, PEDRO; CADENA, ALBERTO

    2013-01-01

    We studied the species richness and two indices of abundance of medium-sizedmammals in areas with Andean forest and Andean alder (Alnus acuminata)reforestations in a reserve at the Central Andes of Colombia. Since reforested areashave a less complex habitat structure and lower plant diversity than native forests, wepredicted that they have lower richness of mammals than areas with Andean forest.We obtained the indices of abundance from direct contacts in transects and from theuse of track sta...

  10. Water-scarcity patterns : spatiotemporal interdependencies between water use and water availability in a semi-arid river basin

    NARCIS (Netherlands)

    Oel, van Pieter Richard

    2009-01-01

    This thesis addresses the interdependencies between water use and water availability and describes a model that has been developed to improve understanding of the processes that drive changes and variations in the spatial and temporal distribution of water resources in a semi-arid river basin. These

  11. Crust-mantle contribution to Andean magmatism

    International Nuclear Information System (INIS)

    There has long been great interest in quantifying the contributions of the continental crust to continental arc magmas, such as those of the Andes using osmium isotopes (Alves et al., 1999; Borg et al., 2000; Brandon et al., 1996; McInnes et al., 1999). In general, Andean volcanic rocks of all compositions show relatively low Sr-isotope ratios and positive to mildly negative epsilon Nd values. Nonetheless, in the Southern Volcanic Zone of central Chile, basalt-andesite-dacite volcanoes along the Quaternary volcanic front were shown (by Hildreth and Moorbath, 1988) to have latitudinally systematic chemical variations, as well as a monotonic increase in 87Sr/Sr86 from ca. 0.7035 to 0.7055 and a decrease in epsilon Nd values from ca. +3 to -1. The isotopic variations correlate with basement elevation of the volcanic edifices and with Bouguer gravity anomalies, both of which are thought to reflect along-arc variations in thickness and average age of the underlying crust. Volcanoes with the most evolved isotopic signatures were fed through the thickest crust. Correlation of chemical and isotopic variations with crustal thickness was interpreted to be caused by Melting (of deep-crustal host rocks), Assimilation, Storage, and Homogenization (MASH) of mantle-derived magmas in long-lived lower-crustal reservoirs beneath each center prior to eruption. We have now determined Os-isotope ratios for a sample suite from these volcanoes (33-36 S lat.), representing a range of crustal thickness from ca. 60-35 km. The samples range in MgO from ca. 8-4% and in SiO2 from 51-57%. The most evolved eruptive products occur above the thickest crust and have 87Sr/86Sr ratios of 0.7054 and epsilon Nd values of -1.5. The 187Os/188Os ratios correlate with the other isotopic systems and with crustal thickness. Volcanoes on the thinnest crust have 187Os/188Os ratios of 0.18-0.21. Those on the thickest crust have 187Os/188Os ratios as high as 0.64. All the Os values are much too radiogenic to

  12. Postmodern Anthropology: Reflections from Andean Ethnohistory

    Directory of Open Access Journals (Sweden)

    Villarías-Robles, Juan J. R.

    2008-06-01

    Full Text Available The postmodern perspective, which began its influence on studies of Prehispanic Peru in the 1980s, has resulted —as chief positive effect— in reflection and debate concerning the written sources for apprehending such cultural otherness, the so-called “Chronicles of the West Indies”: a perspective accompanied by new editions of these texts. The author of the present article expresses his own reflection on such change in theory and method. He argues that, with regard to self-reflectivity on its epistemological foundations, the new perspective is not entirely original in the long history of Andean ethnohistory; in effect, this approach is almost as old as the field itself. What is indeed original is the cognitive relativism that surfaced in some extreme forms of the discussion. It was an unfortunate development, however: when not denying, as a matter of principle, the very possibility of understanding that cultural otherness, arguments masked actual interpretations or explanations of its features that were protected, ipso facto, from a rigorous process of validation.

    La perspectiva posmoderna, que empezó a ser influyente en los estudios del Perú prehispánico en la década de 1980, ha tenido como principal efecto positivo la reflexión y el debate sobre las fuentes originales de conocimiento de esa alteridad cultural, las llamadas genéricamente “Crónicas de Indias”: una perspectiva acompañada de nuevas ediciones de tales textos. El autor del presente artículo hace aquí su propia reflexión sobre este cambio teórico y metodológico. Plantea que, en lo que tiene de discusión sobre sus bases epistemológicas, no es del todo original en la larga historia de la etnohistoria peruanista. Es, de hecho, casi tan antiguo como ella. Lo que sí ha sido original es el relativismo cognitivo que ha acompañado a algunas expresiones extremas de la discusión. Pero fue ésta una novedad desafortunada: cuando no negaba por principio la

  13. Assessing Nonstationary Spatial Patterns of Extreme Droughts from Long-Term High-Resolution Observational Dataset on a Semiarid Basin (Spain

    Directory of Open Access Journals (Sweden)

    Sandra G. Garcia Galiano

    2015-10-01

    Full Text Available In basins of South-eastern Spain; such as the semiarid Segura River Basin (SRB, a strong decrease in runoff from the end of the 1970s has been observed. However, in the SRB the decreasing trend is not only related with climate variability and change, also with intensive reforestation aimed at halting desertification and erosion, whichever the reason is, the default assumption of stationarity in water resources systems cannot be guaranteed. Therefore there is an important need for improvement in the ability of monitoring and predicting the impacts associated with the change of hydrologic regimes. It is thus necessary to apply non-stationary probabilistic models, which are able to reproduce probability density functions whose parameters vary with time. From a high-resolution daily gridded rainfall dataset of more than five decades (1950−2007, the spatial distribution of lengths of maximum dry spells for several thresholds are assessed, applying Generalized Additive Models for Location Scale and Shape (GAMLSS models at the grid site. Results reveal an intensification of extreme drought events in some headbasins of the SRB important for water supply. The identification of spatial patterns of drought hazards at basin scale, associated with return periods; contribute to designing strategies of drought contingency preparedness and recovery operations, which are the leading edge of adaptation strategies.

  14. Ornitholimnology: Effects of grazing by the Andean flamingo (Phoenicoparrus andinus).

    Science.gov (United States)

    Hurlbert, S H; Chang, C C

    1983-08-01

    Experimental exclusion of the Andean flamingo (Phoenicoparrus andinus) from shallow water areas of a salt lake in the Bolivian Andes caused large increases in the biomass of microorganisms inhabiting the surface sediments, especially a large diatom (Surirella wetzeli), amebas, ciliates, and nematodes. This is a conservative demonstration of the influences that water birds in general exert on the structure of aquatic ecosystems. PMID:16593350

  15. Ornitholimnology: Effects of grazing by the Andean flamingo (Phoenicoparrus andinus)

    OpenAIRE

    Hurlbert, Stuart H.; Chang, Cecily C. Y.

    1983-01-01

    Experimental exclusion of the Andean flamingo (Phoenicoparrus andinus) from shallow water areas of a salt lake in the Bolivian Andes caused large increases in the biomass of microorganisms inhabiting the surface sediments, especially a large diatom (Surirella wetzeli), amebas, ciliates, and nematodes. This is a conservative demonstration of the influences that water birds in general exert on the structure of aquatic ecosystems.

  16. Predicting Polylepis distribution: vulnerable and increasingly important Andean woodlands

    OpenAIRE

    Brian R. Zutta; Phillip W. Rundel; Sassan Saatchi; Jorge D. Casana; Paul Gauthier Gauthier; Aldo Soto; Yessenia Velazco; Wolfgang Buermann

    2012-01-01

    Polylepis woodlands are a vital resource for preserving biodiversity and hydrological functions, which will be altered by climate change and challenge the sustainability of local human communities. However, these highaltitude Andean ecosystems are becoming increasingly vulnerable due to anthropogenic pressure including fragmentation, deforestation and the increase in livestock. Predicting the distribution of native woodlands has become increasingly important to counteract the negative effects...

  17. The Andean Common Market: An Experiment in Regional Cooperation.

    Science.gov (United States)

    Carlson, Reynold E.

    The Grupo Andino (GRAN) was formed in 1969 as an effort at economic integration by six Latin American countries (Bolivia, Chile, Columbia, Ecuador, Peru, and Venezuela). It was an outgrowth of its predecessor, the Latin American Free Trade Association (LAFTA), which had been formed in 1960 with eleven member countries. The Andean Group (GRAN) from…

  18. Climate change variability and Andean agriculture: The context

    OpenAIRE

    Valdivia, Corinne

    2008-01-01

    A presentation by Valdivia from lessons learned in the SANREM CRSP and past research to frame the two day workshop. First session of the workshop: I. Climate Change Variability and Andean Agriculture: The Context Lessons learned from SANREM CRSP on adapting to climate change. LTRA-4 (Practices and Strategies for Vulnerable Agro-Ecosystems)

  19. Andean shrublands of Moquegua, South Peru: Prepuna plant communities

    NARCIS (Netherlands)

    Montesinos, D.B.; Cleef, A.M.; Sykora, K.V.

    2012-01-01

    A syntaxonomic overview of shrubland vegetation in the southern Andean regions of Peru is presented. For each plant community, information is given on physiognomy, floristic diversity, ecology and geographical distribution. The shrub vegetation on the slopes of the upper Tambo river valley includes

  20. The astronomy of Andean myth: The history of a cosmology

    Science.gov (United States)

    Sullivan, William F.

    It is shown that Andean myth, on one level, represents a technical language recording astronomical observations of precession and, at the same time, an historical record of simultaneous social and celestial transformations. Topographic and architectural terms of Andean myth are interpreted as a metaphor for the organization of and locations on the celestial sphere. Via ethoastronomical date, mythical animals are identified as stars and placed on the celestial sphere according to their topographical location. Tested in the planetarium, these arrays generate cluster of dates - 200 B.C. and 650 A.D. Analysis of the names of Wiraqocha and Manco Capac indicates they represent Saturn and Jupiter and that their mythical meeting represents their conjunction in 650 A.D. The astronomy of Andean myth is then used as an historical tool to examine how the Andean priest-astronomers recorded the simultaneous creation of the avllu and of this distinctive astronomical system about 200 B.C. The idea that the agricultural avllu, with its double descent system stressing the importance of paternity, represents a transformation of society from an earlier matrilineal/horticultural era is examined in light of the sexual imagery employed in myth. Wiraqocha's androgyny and the division of the celestial sphere into male (ecliptic) and female (celestial equator = earth) are interpreted as cosmological validations of the new social structure.

  1. Diversity for cooking time in Andean dry bean

    Science.gov (United States)

    A diversity panel of 250 dry bean lines from the Andean gene pool was evaluated for cooking time. Cooking time ranged from 17 to 90 min with an average of 36 min. A faster cooking time was also correlated with a number of other seed characteristics, most notably, higher levels of boron and potassium...

  2. Patterns of landscape form in the upper Rhône basin, Central Swiss Alps, predominantly show lithologic controls despite multiple glaciations and variations in rock uplift rates

    Science.gov (United States)

    Stutenbecker, L. A.; Costa, A.; Schlunegger, F.

    2015-10-01

    , where streams yield strong convex long profiles, and where the tributary basins have the highest hypsometric integral and reveal the steepest hillslopes. We interpret this pattern to reflect differences in response times of the fluvial erosion in tributary streams towards glacial and tectonic perturbations, where the corresponding lengths strongly depend on the lithology and therefore on the bedrock erodibility.

  3. Paleo-environment in the upper amazon basin during early to middle Miocene times

    Science.gov (United States)

    van Soelen, Els; Hoorn, Carina; Santos, Roberto V.; Dantas, Elton L.; Sinninghe Damsté, Jaap S.; Kim, Jung-Hyun

    2014-05-01

    The Amazon River has the largest catchment in the world and is responsible for the largest water discharge from land to the ocean. The river system that flows from the Andes to the Atlantic Equatorial Margin exists since the late Miocene, and results from Andean uplift which strongly affected erosion/deposition and major flow patterns in northern South-America. Two outcrop sites from the Solimões basin, Mariñame (17.7-16.1 Ma) and Los Chorros (14.2-12.7 Ma), may shed light on the inland paleo-environmental conditions during a period of active Andean uplift in the early to middle Miocene. Earlier works revealed the Mariñame outcrops to represent a river born in Amazonia. Instead the Los Chorros outcrops are relics of the Amazon River system, characterized by extensive wetlands consisting of swamps, shallow lakes, crevasse splays channels and crevasse-delta lakes (e.g. Hoorn et al., 2010). The freshwater ecosystems alternate with some intervals that are rich in marine palynomorphs (such as dinocysts), mangrove pollen, brackish tolerant molluscs and ostracods, which indicate brackish conditions and a marine influence. It is thought that these marine incursion are related to phases of global sea-level rise and rapid subsidence in the Andean foreland (Marshall & Lundberg, 1996). Still, much remains unknown about the Miocene river systems, like the extent and diversity of the wetland system and the nature of the marine incursions. To get a better understanding of the sources of the (in)organic material, geochemical methods were used. Strontium (Sr) and Neodymium (Nd) isotopes were analyzed on bulk sediments, and used for a paleo-provenance study. The Sr and Nd isotopic signature in the older section (Mariñame) is in general more radiogenic compared to the Los Chorros section. The most radiogenic values are comparable to those found nowadays in the the Precambrian Guyana shield. A Guyana sediment source would suggest a distinctly different flow direction of the major

  4. Helium isotope characteristics of Andean geothermal fluids and lavas

    Science.gov (United States)

    Hilton, D. R.; Hammerschmidt, K.; Teufel, S.; Friedrichsen, H.

    1993-12-01

    The first comprehensive helium isotope survey of the Andes is reported here. We have sampled geothermal fluids and phyric lava flows from the Southern (svz) and Central (cvz) Volcanic Zones, the volcanically active Puna region and the Precordillera, Salta Basin, Longitudinal Valley and the aseismic region between the two volcanic zones. Although the active areas are characterized by significant differences in crustal age and thickness, the svz, cvz and Puna are characterized by a wide and overlapping range in He-3/He-4 ratios (for fluids and phenocrysts) from predominantly radiogenic values to close to the Mid-Ocean Ridge Basalt (MORB) ratio. The measured ranges in He-3/He-4 ratios (R) (reported normalised to the air He-3/He-4 -- R(sub A)) are: svz (0.18 less than R/R(sub A) less than 6.9); cvz (0.82 less than R/R(sub A) less than 6.0); and Puna (1.8 less than R/R(sub A) less than 5.4). Modification of magmatic He-3/He-4 ratios by water/rock interactions (fluids) or post-eruptive grow-in of radiogenic He-4 or preferential diffusive loss of He-3 (phenocrysts) is considered unlikely; this means that the wide range reflects the helium isotope characteristics of magma bodies in the Andean crust. The mechanism controlling the He-3/He-4 ratios appears to be a mixing between mantle (MORB-like) helium and a radiogenic helium component derived from radioactive decay within the magma (magma aging) and/or interaction with He-4-rich country rock: a process expected to be influenced by pre-eruptive degassing of the mantle component. Assimilation of lower crust is also capable of modifying He-3/He-4 ratios, albeit to a much lesser extent. However, it is possible that the highest measured values in each zone were established by the addition of lower crustal radiogenic helium to MORB helium. In this case, the higher 'base level' ratios of the svz would reflect the younger crustal structure of this region. In contrast to helium, there is no overlap in the Sr or Pb isotope

  5. Using Pooled Local Expert Opinions (PLEO to Discern Patterns in Sightings of Live and Dead Manatees (Trichechus senegalensis, Link 1785 in Lower Sanaga Basin, Cameroon.

    Directory of Open Access Journals (Sweden)

    Theodore B Mayaka

    Full Text Available We aimed at unveiling patterns in live and dead manatee sightings in the Lower Sanaga Basin, Cameroon. For this purpose, the expert opinions of 133 local fishers were collected during in-person interviews, distilled using categorical data analysis, and checked against scientific literature. The five main results are as follows: manatees were sighted averagely once a week in lakes, rivers, and the coast & estuaries, mostly in group sizes of 2-3; the odds of sighting live manatees (respectively dead manatees decreased (respectively increased from inland lakes to estuaries and the coast, via rivers; manatee carcasses were reported in all habitats, albeit more frequently in rivers; a distribution map based on fishers' reports show two manatee concentration areas: Lake Ossa and the Malimba-Mbiako section of River Sanaga; the number of manatees was perceived as increasing despite incidental and directed catches. Thus, our findings corroborate earlier assessments of the Lower Sanaga Basin as being a major manatee conservation area. Additionally, from these results and the literature, we identified three hypotheses about local manatee persistence: deep pools such as lakes offer year round sanctuaries, not just dry-season refugia; seasonality of specific habitat variables determine manatee occurrence patterns; and local variability in habitat encroachment mediate the meta-population dynamics of manatee in the Lower Sanaga Basin. Finally, we examine the implications for data requirements in light of the small ecological scale at which the surveyed fishers ply their trade. Thus, consonant with the Malawi principles for the ecosystem approach to management (www.cbd.int/ecosystem, we recommend collecting data preferably at landscape scale, through a participatory monitoring program that fully integrates scientific and traditional knowledge systems. This program should include, amongst others, a standardised necropsy protocol for collecting mortality and

  6. Using Pooled Local Expert Opinions (PLEO) to Discern Patterns in Sightings of Live and Dead Manatees (Trichechus senegalensis, Link 1785) in Lower Sanaga Basin, Cameroon.

    Science.gov (United States)

    Mayaka, Theodore B; Takoukam Kamla, Aristide; Self-Sullivan, Caryn

    2015-01-01

    We aimed at unveiling patterns in live and dead manatee sightings in the Lower Sanaga Basin, Cameroon. For this purpose, the expert opinions of 133 local fishers were collected during in-person interviews, distilled using categorical data analysis, and checked against scientific literature. The five main results are as follows: manatees were sighted averagely once a week in lakes, rivers, and the coast & estuaries, mostly in group sizes of 2-3; the odds of sighting live manatees (respectively dead manatees) decreased (respectively increased) from inland lakes to estuaries and the coast, via rivers; manatee carcasses were reported in all habitats, albeit more frequently in rivers; a distribution map based on fishers' reports show two manatee concentration areas: Lake Ossa and the Malimba-Mbiako section of River Sanaga; the number of manatees was perceived as increasing despite incidental and directed catches. Thus, our findings corroborate earlier assessments of the Lower Sanaga Basin as being a major manatee conservation area. Additionally, from these results and the literature, we identified three hypotheses about local manatee persistence: deep pools such as lakes offer year round sanctuaries, not just dry-season refugia; seasonality of specific habitat variables determine manatee occurrence patterns; and local variability in habitat encroachment mediate the meta-population dynamics of manatee in the Lower Sanaga Basin. Finally, we examine the implications for data requirements in light of the small ecological scale at which the surveyed fishers ply their trade. Thus, consonant with the Malawi principles for the ecosystem approach to management (www.cbd.int/ecosystem), we recommend collecting data preferably at landscape scale, through a participatory monitoring program that fully integrates scientific and traditional knowledge systems. This program should include, amongst others, a standardised necropsy protocol for collecting mortality and biological data

  7. Seismic imaging of the upper mantle beneath the northern Central Andean Plateau: Implications for surface topography

    Science.gov (United States)

    Ward, K. M.; Zandt, G.; Beck, S. L.; Wagner, L. S.

    2015-12-01

    Extending over 1,800 km along the active South American Cordilleran margin, the Central Andean Plateau (CAP) as defined by the 3 km elevation contour is second only to the Tibetan Plateau in geographic extent. The uplift history of the 4 km high Plateau remains uncertain with paleoelevation studies along the CAP suggesting a complex, non-uniform uplift history. As part of the Central Andean Uplift and the Geodynamics of High Topography (CAUGHT) project, we use surface waves measured from ambient noise and two-plane wave tomography to image the S-wave velocity structure of the crust and upper mantle to investigate the upper mantle component of plateau uplift. We observe three main features in our S-wave velocity model including (1), a high velocity slab (2), a low velocity anomaly above the slab where the slab changes dip from near horizontal to a normal dip, and (3), a high-velocity feature in the mantle above the slab that extends along the length of the Altiplano from the base of the Moho to a depth of ~120 km with the highest velocities observed under Lake Titicaca. A strong spatial correlation exists between the lateral extent of this high-velocity feature beneath the Altiplano and the lower elevations of the Altiplano basin suggesting a potential relationship. Non-uniqueness in our seismic models preclude uniquely constraining this feature as an uppermost mantle feature bellow the Moho or as a connected eastward dipping feature extending up to 300 km in the mantle as seen in deeper mantle tomography studies. Determining if the high velocity feature represents a small lithospheric root or a delaminating lithospheric root extending ~300 km into the mantle requires more integration of observations, but either interpretation shows a strong geodynamic connection with the uppermost mantle and the current topography of the northern CAP.

  8. Can local climate variability be explained by weather patterns? A multi-station evaluation for the Rhine basin

    OpenAIRE

    Murawski, Aline; Bürger, Gerd; Vorogushyn, Sergiy; MERZ, Bruno

    2016-01-01

    For understanding past flood changes in the Rhine catchment and in particular for quantifying the role of anthropogenic climate change for extreme flows, an attribution study relying on a proper GCM (General Circulation Model) downscaling is needed. A downscaling based on conditioning a stochastic weather generator on weather patterns is a promising approach given, among others, a strong link between weather patterns and local climate, and sufficient GCM skill in reproducing weather pattern ...

  9. Late Glacial-Holocene climatic transition record at the Argentinian Andean piedmont between 33-34° S

    Science.gov (United States)

    Mehl, A. E.; Zárate, M. A.

    2013-10-01

    The Arroyo La Estacada (~33°28' S, 69°02' W), eastern Andean piedmont of Argentina, cuts through an extensive piedmont aggradational unit composed of a dominant late Pleistocene-early Holocene (LP-EH) alluvial sequence including several paleosols. The arroyo sedimentary record exhibits a paleosol developed affecting the topmost part of likely Lateglacial aeolian deposits aggraded into a floodplain environment by the end of the late Pleistocene. The paleosol shows variable grade of development in the outcrops along the arroyo probably in relation to fluvial valley paleotopography. Organic matter humification, carbonate accumulation and redox processes were the dominant processes associated with paleosol formation. By the early Holocene, when the formation of the paleosol ended, alluvial aggradation renewed and a higher frequency of flooding events could have affected the arroyo's floodplain environment. A period of relative landscape stability in the Arroyo La Estacada basin is inferred from the paleosol developed by the LP-EH transition in response to a climatic amelioration in the Andes cordillera piedmont after the Late Glacial arid conditions. The renewal of early Holocene alluvial aggradation was probably influenced by the South American Monsoon and resulted in a change in the sedimentary dynamics of the arroyo. The analyzed Late Glacial-Holocene alluvial record of the Andean piedmont constitutes a suitable record of the LP-EH climatic transition at the extra Andean region of Argentina. It is in agreement with regional paleoclimatic evidence along the southern tip of the South American continent, where other sedimentary sequences record similar late Quaternary paleoenvironmental changes over both fluvial and interfluvial areas.

  10. Structural inheritance and selective reactivation in the central Andes: Cenozoic deformation guided by pre-Andean structures in southern Peru

    Science.gov (United States)

    Perez, Nicholas D.; Horton, Brian K.; Carlotto, Victor

    2016-03-01

    Structural, stratigraphic, and geochronologic constraints from the Eastern Cordillera in the central Andean plateau of southern Peru (14-15°S) demonstrate the existence and position of major pre-Andean structures that controlled the accumulation of Triassic synrift fill and guided subsequent Cenozoic deformation. The timing of initial clastic deposition of the Triassic Mitu Group is here constrained to ~ 242-233 Ma on the basis of detrital and volcanic zircon U-Pb geochronology. Regionally distinct provenance variations, as provided by U-Pb age populations from localized synrift accumulations, demonstrate Triassic erosion of multiple diagnostic sources from diverse rift-flank uplifts. Stratigraphic correlations suggest synchronous initiation of extensional basins containing the Mitu Group, in contrast with previous interpretations of southward rift propagation. Triassic motion along the NE-dipping San Anton normal fault accommodated up to 7 km of throw and hanging-wall deposition of a synrift Mitu succession > 2.5 km thick. The contrasting orientation of a non-reactivated Triassic normal fault suggests selective inversion of individual structures in the Eastern Cordillera was dependent on fault dip and strike. Selective preservation of a ~ 4 km thick succession of Carboniferous-Permian strata in the down-dropped San Anton hanging wall, beneath the synrift Mitu Group, suggests large-scale erosional removal in the uplifted footwall. Field and map observations identify additional pre-Andean thrust faults and folds attributed to poorly understood Paleozoic orogenic events preserved in the San Anton hanging wall. Selective thrust reactivation of normal and reverse faults during later compression largely guided Cenozoic deformation in the Eastern Cordillera. The resulting structural compartmentalization and across-strike variations in kinematics and deformation style highlight the influence of inherited Paleozoic structures and Triassic normal faults on the long

  11. Optimization of a development well pattern based on production performance: A case study of the strongly heterogeneous Sulige tight sandstone gas field, Ordos Basin

    Directory of Open Access Journals (Sweden)

    Yuegang Li

    2015-01-01

    Full Text Available As a typical tight sandstone gas field with strong heterogeneity, the Sulige Gas Field in the Ordos Basin faces major challenges in its development because the reservoirs in the gas field are small in effective sand scale, rapid in lithologic change, strong in plane heterogeneity, and poor in connectivity. How to scientifically deploy development wells to improve the recovery is the most important issue for the successful development of this kind of gas fields. Therefore, a well inference analysis was conducted to figure out the impact of well pattern density on the recovery based on the research of many years in gas field development methods and the summary of practical effect. In this paper, we put forward for the first time the concept of inter-well interference probability, and present the relationship between the probability of inter-well interference and well pattern density of the Sulige Gas Field. Then we established a mathematical model for the optimization of development well pattern by combining fine sand anatomy, reservoir engineering, numerical simulation and economic evaluation, and obtained a quantitative relationship between recovery and well pattern density. Furthermore, on the basis of comprehensive analysis, a reasonable development well pattern was designed for the Sulige Gas Field: this well pattern is parallelogram in shape, with a density of 3.1 wells/km2, well spacing of 500 m, and row spacing of 650 m. Development practices have confirmed that this scheme is capable of achieving better economic benefits, producing geological reserves as far as possible and improving the ultimate recovery of such gas fields.

  12. The effects of governance modes on the energy matrix of Andean countries

    International Nuclear Information System (INIS)

    This article addresses the consequences of different modes of energy governance on the energy matrix. Energy governance is understood as a regulation system of the energy related interplays between the State, the society and the economy. The energy matrix is a useful instrument for comparative policy analysis, since it informs us about production and consumption trends, by sources and sectors. Our central argument is that energy governance follows two different patterns, one hierarchical and the other cooperative, that are not necessarily determined by the initial factors allocation, and produce different effects on the energy matrix. Hierarchical governance is based on centralized decision-making and State-centered development, while co-governance is based on decentralized decision-making and market-oriented development. To develop this argument, we compare the energy matrix from the five Andean countries (Venezuela, Colombia, Ecuador, Peru and Bolivia).

  13. Infection of Myxobolus galaxii (Myxozoa) in Galaxias maculatus (Osmeriformes: Galaxiidae) from northwestern Patagonian Andean lakes (Argentina).

    Science.gov (United States)

    Flores, Verónica; Viozzi, Gustavo

    2007-04-01

    The infection of Myxobolus galaxii Szidat, 1953, from the musculature and abdominal organs of northwestern Patagonian Galaxias maculatus is described. Plasmodia are histozoic and intercellular. Spores are pyriform in valvar view and biconvex in sutural view, with 4-9 edge notches in the sutural line, varying in shape within the same plasmodium. Myxobolus galaxii was detected in fish from 7 of 17 Andean Patagonian lakes, with prevalences ranging between 2 and 17%. A repeating pattern of summer increment in prevalence was observed, which could be explained by the ontogenetic migratory movements of the fish in Lake Gutiérrez. Also, accumulation of plasmodia through the life span of fish was detected. PMID:17539428

  14. The effects of governance modes on the energy matrix of Andean countries

    Energy Technology Data Exchange (ETDEWEB)

    Fontaine, Guillaume, E-mail: gfontaine@flacso.org.e [Latin American Faculty for Social Sciences (FLACSO), Research Laboratory on Governance, Quito (Ecuador)

    2011-05-15

    This article addresses the consequences of different modes of energy governance on the energy matrix. Energy governance is understood as a regulation system of the energy related interplays between the State, the society and the economy. The energy matrix is a useful instrument for comparative policy analysis, since it informs us about production and consumption trends, by sources and sectors. Our central argument is that energy governance follows two different patterns, one hierarchical and the other cooperative, that are not necessarily determined by the initial factors allocation, and produce different effects on the energy matrix. Hierarchical governance is based on centralized decision-making and State-centered development, while co-governance is based on decentralized decision-making and market-oriented development. To develop this argument, we compare the energy matrix from the five Andean countries (Venezuela, Colombia, Ecuador, Peru and Bolivia).

  15. Effect of wetland management: are lentic wetlands refuges of plant-species diversity in the Andean-Orinoco Piedmont of Colombia?

    Science.gov (United States)

    Murillo-Pacheco, Johanna I; Rös, Matthias; Escobar, Federico; Castro-Lima, Francisco; Verdú, José R; López-Iborra, Germán M

    2016-01-01

    Accelerated degradation of the wetlands and fragmentation of surrounding vegetation in the Andean-Orinoco Piedmont are the main threats to diversity and ecological integrity of these ecosystems; however, information on this topic is of limited availability. In this region, we evaluated the value of 37 lentic wetlands as reservoirs of woody and aquatic plants and analyzed diversity and changes in species composition within and among groups defined according to management given by: (1) type (swamps, heronries, rice fields, semi-natural lakes, constructed lakes and fish farms) and (2) origins (natural, mixed and artificial). A total of 506 plant species were recorded: 80% woody and 20% aquatic. Of these, 411 species (81%) were considered species typical of the area (Meta Piedmont distribution). Diversity patterns seem to be driven by high landscape heterogeneity and wetland management. The fish farms presented the highest diversity of woody plants, while swamps ranked highest for aquatic plant diversity. Regarding wetland origin, the artificial systems were the most diverse, but natural wetlands presented the highest diversity of typical species and can therefore be considered representative ecosystems at the regional scale. Our results suggest that lentic wetlands act as refuges for native vegetation of Meta Piedmont forest, hosting 55% of the woody of Piedmont species and 29% of the aquatic species of Orinoco basin. The wetlands showed a high species turnover and the results indicated that small wetlands (mean ± SD: size = 11 ± 18.7 ha), with a small area of surrounding forest (10 ± 8.6 ha) supported high local and regional plant diversity. To ensure long-term conservation of lentic wetlands, it is necessary to develop management and conservation strategies that take both natural and created wetlands into account. PMID:27602263

  16. Rift initiation in cratonic lithosphere: Seismicity patterns in the Manyara-Natron-Magadi basins and Oldoinyo Lengai volcano

    Science.gov (United States)

    Lambert, C.; Rodzianko, A.; Rasendra, N.; Msabi, M.; Muirhead, J.; Ebinger, C. J.; Tiberi, C.; Roecker, S. W.; Ferdinand, R. W.; Mtelela, K.; Muzuka, A.

    2013-12-01

    The CRAFTI project consists of a 2-year seismic acquisition program to quantify the partitioning of strain between faulting and magmatism during the early stages of continental rifting in Archaean and Proterozoic lithosphere. The Kenya provides an ideal study system, as it comprises several rift segments at different stages of the rifting cycle. We present preliminary results from 38 broadband seismometers deployed in Tanzania in January 2013, and 4 stations in Kenya deployed in July 2013. The network includes a rift-perpendicular transect, and spans parts of 3 discrete rift basins in different stages of development: Manyara, Natron, Magadi. Initial analyses indicate relatively low noise levels at all stations deployed in Maasai bomas and rural schools, and good to excellent transmission, except near Quaternary Gelai, Oldoinyo Lengai, and Kitumbeine volcanoes. We present time-space relations of seismicity for the first 6 months' of data, and focal mechanisms for the largest events during that time period. Hypocentral locations are compared with the locations of eruptive centers, dike intrusions, and sub-surface projections of faults mapped in a complementary part of the CRAFTI project. The spatial and temporal distribution of earthquake activity will help identify the contributions of faulting and magmatism in each basin, and in the identification of subsurface magma reservoirs in this youthful rift system.

  17. Effects of land-use patterns on in-stream nitrogen in a highly-polluted river basin in Northeast China.

    Science.gov (United States)

    Bu, Hongmei; Zhang, Yuan; Meng, Wei; Song, Xianfang

    2016-05-15

    This study investigated the effects of land-use patterns on nitrogen pollution in the Haicheng River basin in Northeast China during 2010 by conducting statistical and spatial analyses and by analyzing the isotopic composition of nitrate. Correlation and stepwise regressions indicated that land-use types and landscape metrics were correlated well with most river nitrogen variables and significantly predicted them during different sampling seasons. Built-up land use and shape metrics dominated in predicting nitrogen variables over seasons. According to the isotopic compositions of river nitrate in different zones, the nitrogen sources of the river principally originated from synthetic fertilizer, domestic sewage/manure, soil organic matter, and atmospheric deposition. Isotope mixing models indicated that source contributions of river nitrogen significantly varied from forested headwaters to densely populated towns of the river basin. Domestic sewage/manure was a major contributor to river nitrogen with the proportions of 76.4±6.0% and 62.8±2.1% in residence and farmland-residence zones, respectively. This research suggested that regulating built-up land uses and reducing discharges of domestic sewage and industrial wastewater would be effective methods for river nitrogen control. PMID:26925734

  18. Active Andean volcanism: its geologic and tectonic setting

    OpenAIRE

    CHARLES R STERN

    2004-01-01

    The Andean volcanic arc includes over 200 potentially active Quaternary volcanoes, and at least 12 giant caldera/ignimbrite systems, occurring in four separate segments referred to as the Northern, Central, Southern and Austral Volcanic Zones. Volcanism results from subduction of the Nazca and Antarctic oceanic plates below South America. Active volcanoes occur where the angle of subduction is relatively steep (25°), and active arc segments are separated by regions below which subduction angl...

  19. Andean grasslands are as productive as tropical cloud forests

    OpenAIRE

    Oliveras Menor, I.; Girardin, C; Doughty, C. E.; Cahuana, N.; Arenas, C. E.; Oliver, V.; Huaraca Huasco, W.; Malhi, Y.

    2014-01-01

    We aim to assess net primary productivity (NPP) and carbon cycling in Andean tropical alpine grasslands (puna) and compare it with NPP of tropical montane cloud forests. We ask the following questions: (1) how do NPP and soil respiration of grasslands vary over the seasonal cycle? (2) how do burning and grazing affect puna productivity? (3) if the montane forest expands into the puna, what will be the resulting change in productivity? The study sites are located at the South-eastern Peruvian ...

  20. Climate Change Forces New Ecological States in Tropical Andean Lakes

    OpenAIRE

    Michelutti, Neal; Wolfe, Alexander P.; Cooke, Colin A.; Hobbs, William O.; Vuille, Mathias; John P. Smol

    2015-01-01

    Air temperatures in the tropical Andes have risen at an accelerated rate relative to the global average over recent decades. However, the effects of climate change on Andean lakes, which are vital to sustaining regional biodiversity and serve as an important water resource to local populations, remain largely unknown. Here, we show that recent climate changes have forced alpine lakes of the equatorial Andes towards new ecological and physical states, in close synchrony to the rapid shrinkage ...

  1. State dilemmas in applying the Previous Consultation Law in the Andean Region

    Directory of Open Access Journals (Sweden)

    Rafael Barrio de Mendoza

    2013-12-01

    Full Text Available The Peruvian government enacted a new law granting consultation rights to indigenous peoples as a mechanism to enhance social inclusion in the country. The law generated debates about the criteria to identify indigenous population in the Andean region. Why does this law have problems granting consultation rights to Andean people? This paper aims to answer the question by reviewing historically the different Andean identities and analyzing the current international debate on indigenity. Our main argument is that the government intrying to apply the law is structuring a restrictive model that is hardlyable to grasp the complexity and dynamism of Andean identities.

  2. Predicting Polylepis distribution: vulnerable and increasingly important Andean woodlands

    Directory of Open Access Journals (Sweden)

    Brian R. Zutta

    2012-11-01

    Full Text Available Polylepis woodlands are a vital resource for preserving biodiversity and hydrological functions, which will be altered by climate change and challenge the sustainability of local human communities. However, these highaltitude Andean ecosystems are becoming increasingly vulnerable due to anthropogenic pressure including fragmentation, deforestation and the increase in livestock. Predicting the distribution of native woodlands has become increasingly important to counteract the negative effects of climate change through reforestation and conservation. The objective of this study was to develop and analyze the distribution models of two species that form extensive woodlands along the Andes, namely Polylepis sericea and P. weberbaueri. This study utilized the program Maxent, climate and remotely sensed environmental layers at 1 km resolution. The predicted distribution model for P. sericea indicated that the species could be located in a variety of habitats along the Andean Cordillera, while P. weberbaueri was restricted to the high elevations of southern Peru and Bolivia. For both species, elevation and temperature metrics were the most significant factors for predicted distribution. Further model refinement of Polylepis and other Andean species using increasingly available satellite data demonstrate the potential to help define areas of diversity and improve conservation strategies for the Andes.

  3. Two new trans-Andean species of Imparfinis Eigenmann & Norris, 1900 (Siluriformes: Heptapteridae from Colombia

    Directory of Open Access Journals (Sweden)

    Armando Ortega-Lara

    2011-01-01

    Full Text Available Two new species of Imparfinis are described from the trans-Andean region of Colombia. Imparfinis timana is diagnosed by having longer anal fin base (12.4-15.5% in SL, in combination with long adipose fin (24.6-31.3% in SL, 5-6 gill rakers on the first ceratobranchial, 42-43 vertebrae and additional measurements. Imparfinis usmai is distinguished by the combination of first ray of dorsal fin longest, but not projected as a long filament, long adipose fin (21.1-27.0% in SL, maxillary barbel exceeding pelvic-fin base, 39-40 vertebrae, upper caudal-fin lobe pointed and longer than lower lobe, lower lobe rounded, 7-8 gill rakers on the first ceratobranchial, as well as additional measurements. Imparfinis timana is only known from río Guarapas, a small tributary of the upper course of the río Magdalena. Imparfinis usmai is broadly distributed in the upper basin of ríos Cauca and Magdalena, and in the lower Patía river basin. The restricted distribution of I. nemacheir to trans-Andean drainages (Atrato, Magdalena, and Lago de Maracaibo is also discussed.Duas novas espécies do gênero Imparfinis são descritas da região transandina da Colômbia. Imparfinis timana é diagnosticada por possuir as nadadeiras adiposa e anal compridas (24,6-31,3% e 12,4-15,5% no CP, respectivamente, 5-6 rastros branquiais no primeiro ceratobranquial, 42-43 vértebras, além de outros caracteres de morfometria. Imparfinis usmai é diferenciada pela combinação do primeiro raio da nadadeira dorsal longo, mas não projetado como um filamento comprido, nadadeira adiposa longa (21,1-27,0% na CP, barbilhões maxilares ultrapassando a base da nadadeira ventral, 39-40 vértebras, lóbulo superior da nadadeira caudal pontiagudo e mais longo que o lóbulo inferior, lóbulo inferior arredondado, 7-8 rastros branquiais no primeiro ceratobranquial e outros caracteres de morfometria. Imparfinis timana é conhecida somente para o rio Guarapas, pequeno tributário da bacia do alto

  4. Characterising the hydrothermal circulation patterns beneath thermal springs in the limestones of the Carboniferous Dublin Basin, Ireland: a geophysical and geochemical approach.

    Science.gov (United States)

    Blake, Sarah; Henry, Tiernan; Muller, Mark R.; Jones, Alan G.; Moore, John Paul; Murray, John; Campanyà, Joan; Vozár, Jan; Walsh, John; Rath, Volker

    2016-04-01

    A hydrogeological conceptual model of the sources, circulation pathways and temporal variations of two low-enthalpy thermal springs is derived from a multi-disciplinary approach. The springs are situated in the Carboniferous limestones of the Dublin Basin, in east-central Ireland. Kilbrook spring (Co. Kildare) has the highest recorded temperatures for any thermal spring in Ireland (maximum of 25.0 °C), and St. Gorman's Well (Co. Meath) has a complex and variable temperature profile (maximum of 21.8 °C). These temperatures are elevated with respect to average Irish groundwater temperatures (9.5 - 10.5 °C), and represent a geothermal energy potential, which is currently under evaluation. A multi-disciplinary investigation based upon audio-magnetotelluric (AMT) surveys, time-lapse temperature and chemistry measurements, and hydrochemical analysis, has been undertaken with the aims of investigating the provenance of the thermal groundwater and characterising the geological structures facilitating groundwater circulation in the bedrock. The hydrochemical analysis indicates that the thermal waters flow within the limestones of the Dublin Basin, and there is evidence that Kilbrook spring receives a contribution from deep-basinal fluids. The time-lapse temperature, electrical conductivity and water level records for St. Gorman's Well indicate a strongly non-linear response to recharge inputs to the system, suggestive of fluid flow in karst conduits. The 3-D electrical resistivity models of the subsurface revealed two types of geological structure beneath the springs; (1) Carboniferous normal faults, and (2) Cenozoic strike-slip faults. These structures are dissolutionally enhanced, particularly where they intersect. The karstification of these structures, which extend to depths of at least 500 m, has provided conduits that facilitate the operation of a relatively deep hydrothermal circulation pattern (likely estimated depths between 240 and 1,000 m) within the Dublin

  5. A Tale of an Isotope: Where Does the Water Come from in Tropical Andean Ecosystems? A Case of Study in South Ecuador

    Science.gov (United States)

    Mosquera, Giovanny; Breuer, Lutz; Windhorst, David; Célleri, Rolando; Lazo, Patricio; Vaché, Kellie; Crespo, Patricio

    2015-04-01

    Only few catchments in the Andean mountain range are currently monitored. Most basins in the region remain ungauged, and as a result, little knowledge is available on the processes governing their hydrological behavior. In particular, despite the importance of tropical alpine grasslands of the northern Andes (commonly known as the páramo) as providers of abundant high-quality water for downstream populations as well as a variety of other environmental services, very little is known about their hydrologic functioning. Understanding the hydrological behavior of the fragile Andean páramo ecosystems is critical given their high susceptibility to global and local stressors such as changes in land use, and the impacts of climate change and variability. To improve this situation, an analysis of the isotopic composition of oxygen-18 in the Zhurucay River experimental catchment (7.53 km2) located in south Ecuador between 3400 and 3900 m a.s.l. was conducted. Water samples for isotopic analysis were collected in rainfall, streamflow, and soils between May 2011 and May 2013. The main soils in the study site are the Andosols mainly located in the steep slopes, and the Histosols (Andean páramo wetlands) predominantly located at the bottom of the valley. Results from the tracer analysis show that pre-event water stored in the Histosols is the primary source of runoff generation, demonstrating hydrologic connectivity between the Histosols and the drainage network; while the most common soils, the Andosols, laterally drain the infiltrated rainfall recharging the lower situated Histosols. Overall, these findings depict that the use of stable isotopes for investigating hydrological processes at catchment scale provides a more complete understanding of the ecosystem's hydrologic functioning. Moreover, in developing regions, such as the Andean region, acquiring better understanding of the origin and fate of water is a crucial step towards the establishment of scientifically

  6. Two new cis-Andean species of the South American catfish genus Megalonema allied to trans-Andean Megalonema xanthum, with description of a new subgenus (Siluriformes: Pimelodidae

    Directory of Open Access Journals (Sweden)

    John G. Lundberg

    2008-01-01

    Full Text Available A revised diagnosis of the pimelodid catfish genus Megalonema is given based on synapomorphic features of the Weberian complex and gas bladder. Megalonema xanthum from the Magdalena River is redescribed. Two new cis-Andean species of Megalonema are described, M. amaxanthum n. sp. from the Amazon River basin, and M. orixanthum n. sp. from the Orinoco River basin. These three species are differentially diagnosed by shape and size of the supraoccipital posterior process, adipose-fin shape, vertebral counts, eye size, premaxillary bone shape and dentition, length of the anal-fin base, width between the posterior nostrils and presence/absence of dentations on the pectoral spine. Eretmomegalonema new subgenus is established for M. xanthum, M. amaxanthum and M. orixanthum and supported by the uniquely synapomorphic paddle-like structure of its pelvic fin and hypertrophied basipterygium. Unambiguous synapomorphies indicate a sister-group relationship between M. amaxanthum and M. orixanthum, with M. xanthum basal to this pair. This topology is congruent with the Neogene origins of separate Magdalena, Amazon and Orinoco basins suggesting vicariant control of diversification of Eretmomegalonema.Uma diagnose do gênero Megalonema é fornecida baseada em caracteres sinapomórficos do aparelho de Weber e da bexiga natatória. Megalonema xanthum do rio Magdalena, é redescrita. Duas novas espécies cis-Andinas de Megalonema são descritas: M. amaxanthum sp. n. da bacia Amazônica, e M. orixanthum da bacia do rio Orinoco. Estas três espécies são diagnosticadas pela forma e tamanho do processo supraoccipital posterior, forma da nadadeira adiposa, contagem do número de vértebras, tamanho do olho, forma do premaxilar e dentição, comprimento da base da nadadeira anal, distância entre as narinas posteriores, e presença/ausência de dentições no espinho da nadadeira peitoral. Eretmomegalonema, novo subgênero, é estabelecido para M. xanthum, M. amaxanthum

  7. Banding chromosome pattern of two species of Pimelodus (Siluriformes, Pimelodidae) from the Parana River basin of Brazil.

    Science.gov (United States)

    de Souza, Lenice; Giuliano-Caetano, Lucia; Dias, Ana Lúcia

    2004-01-01

    Cytogenetic studies were carried out on seven specimens of Pimelodus heraldoi and sixteen specimens of Pimelodus sp., both from the Parana River basin. The two species had the same diploid number of 56 chromosomes: P. heraldoi with 22M+22SM+6ST+6A and FN of 106 and Pimelodus sp. with 24M+26SM+4ST+2A and FN of 110. NORs were found at the terminal position of the long arm of one pair of ST chromosomes. C-banding (CB) showed in the two species heterochromatin distributed in various chromosomes of the complement, mainly in telomeric regions and in a pair of metacentric chromosomes with strong heterochromatic staining in both telomeres. Treatment only with the fluorochrome CMA3 confirmed in Pimelodus heraldoi and Pimelodus sp. the nucleolar chromosome pair and showed other fluorescent bands. Combined treatment with CB+CMA3 enhanced fluorescent staining of chromosomes in the two fish species evidencing several bands, including in P. heraldoi a chromosome pair showing fluorescent staining in both telomeres. PMID:19058555

  8. Depositional Patterns and Oil/Gas Accumulation Features of Sha-3 Member Turbidites in Dongying Depression, Bohai Bay Basin

    Institute of Scientific and Technical Information of China (English)

    BaiGuoping; ZhangShanwen

    2004-01-01

    Recent exploration results indicate that a significant exploration potential remains in the Dongying Depression of the Bohai Bay Basin and the undiscovered oil and gas are largely reservoired in subtle traps including turbidite litholigeal traps of the Sha-3 Member. In order to effectively guide the exploration program targeting turbidites, this study will focus on the depositional models of the Sha-3 Member turbidites and oil/gas accumulation characteristics in these turbidites. Two corresponding relationships were found. One is that the East African Rift Valley provides a modem analog for the depositionai systems in the Dongying Depression. The other is that the depositional models of line-sourced slope aprons, single point-source submarine fan and multiple source romp turbidite, established for deep.sea turbidites, can be applied to interpret the depositional features of the turbidite fans of three differant origins: slope turbidite aprons, lake floor turbidite fans and delia-fed turbidite fans in the Sha-3 Member. Updip sealing integrity is the key factor determining whether oil/gas accumulates or not in the slope aprons and lake floor fans. The factors controlling oil/gas migration and accumulation in the delta-ted turbidite fans are not very clear. Multiple factors rather than a single factor probably played significant roles in these processes.

  9. Identification of spatiotemporal patterns of biophysical droughts in semi-arid region - a case study of the Karkheh river basin in Iran

    Science.gov (United States)

    Kamali, B.; Abbaspour, K. C.; Lehmann, A.; Wehrli, B.; Yang, H.

    2015-06-01

    This study aims at identifying historical patterns of meteorological, hydrological, and agricultural (inclusively biophysical) droughts in the Karkheh River Basin (KRB), one of the nine benchmark watersheds of the CGIAR Challenge Program on Water and Food. Standardized precipitation index (SPI), standardized runoff index (SRI), and soil moisture deficit index (SMDI) were used to represent the above three types of droughts, respectively. The three drought indices were compared across temporal and spatial dimensions. Variables required for calculating the indices were obtained from the Soil and Water Assessment Tool (SWAT) constructed for the region. The model was calibrated based on monthly runoff and yearly wheat yield using the Sequential Uncertainty Fitting (SUFI-2) algorithm. Five meteorological drought events were identified in the studied period (1980-2004), of which four corresponded with the hydrological droughts with 1-3 month lag. The meteorological droughts corresponded well with the agricultural droughts during dry months (May-August), while the latter lasted for a longer period of time. Analysis of drought patterns showed that southern parts of the catchment were more prone to agricultural drought, while less influenced by hydrological drought. Our analyses highlighted the necessity for monitoring all three aspects of drought for a more effective watershed management. The analysis on different types of droughts in this study provides a framework for assessing their possible impacts under future climate change in semi-arid areas.

  10. Human impact on the hydrology of the Andean páramos

    Science.gov (United States)

    Buytaert, Wouter; Célleri, Rolando; De Bièvre, Bert; Cisneros, Felipe; Wyseure, Guido; Deckers, Jozef; Hofstede, Robert

    2006-11-01

    This paper analyses the problems involved in the conservation and management of the hydrological system of the South American páramo. The páramo consists of a collection of neotropical alpine grassland ecosystems covering the upper region of the northern Andes. They play a key role in the hydrology of the continent. Many of the largest tributaries of the Amazon basin have their headwaters in the páramo. It is also the major water source for the Andean highlands and a vast area of arid and semi-arid lowlands, where páramo water is used for domestic, agricultural and industrial consumption, and the generation of hydropower. Recently, the páramo is increasingly used for intensive cattle grazing, cultivation, and pine planting, among others. These activities, as well as global phenomena such as climate change, severely alter the hydrological regime. A review on the state of knowledge of its hydrology is given in a first part. In a second part, the impact of human activities and climate change on the hydrology of the páramo is discussed.

  11. Distribution pattern and exploration prospect of Longwangmiao Fm reservoirs in the Leshan-Longnüsi Paleouplift, Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Li Yalin

    2014-10-01

    Full Text Available The Longwangmiao Fm gas pool was found in 2012 in Moxi area in Leshan-Longnüsi Paleouplift, central Sichuan Basin. Previous geological studies showed that the Lower Cambrian Longwangmiao Fm reservoir is mainly pore type reservoir of grain shoal facies, locally superimposed by the vuggy reservoir formed by Caledonian karstification, and the distribution of the reservoir has a critical control effect on the gas pool there. Therefore, the reservoir prediction in this area follows the approach of “looking for the overlap of shoal facies, karst, bright spots, and traps”. First, the favorable facies boundary and karstification effect range are defined based on sedimentary facies; on the basis of precise correlation of the top and bottom horizons of the reservoir, the favorable development area of the reservoir was then predicted according to the seismic response characteristics of “bright spots” of the Longwangmiao Fm reservoir; finally, favorable exploration areas were selected according to the effective configuration of reservoir and trap. Due to the horizontal change in reservoir and lithology, Longwangmiao Fm top has no uniform interface features on the seismic profile, making it difficult to trace. In the actual interpretation process, the underlying reference horizon is sought out first, then the bottom boundary of Longwangmiao Fm is correlated, and finally its top boundary is correlated. The prediction results indicated that the Longwangmiao reservoir distributes in band shape in a wide range around the Paleouplift; and the exploration prospects mainly involve three domains: lithologic-stratigraphic traps near the pinchout line of Longwangmiao Fm; lithologic traps formed by isolated shoal body; and structural and lithologic traps at the north flank of the Paleouplift.

  12. Basin development and tectonic history of the Llanos Basin, Eastern Cordillera, and Middle Magdalena Valley, Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, M.A. [PanCanadian Petroleum, Calgary, Alberta (Canada); Addison, F.T.; Alvarez, R. [BP Exploration Ltd., Bogota (Colombia)] [and others

    1995-10-01

    The Middle Magdalena Valley, Eastern Cordillera, and Llanos basin constituted a major regional sedimentary basin from the Triassic to the middle Miocene. Basin development began during the Triassic to the earliest Cretaceous with a synrift megasequence related to the separation of North and South America in the proto-Caribbean. The synrift megasequence began with deposition in a continental environment that became paralic and shallow marine in the Early Cretaceous. Basin development continued into the Cretaceous in a back-arc setting east of the Andean subduction zone. The back-arc megasequence was dominated by shallow-marine sedimentation and produced an excellent regional source rock during the Turonian-Coniacian. Marine deposition was abruptly terminated during the early Maastrichtian due to the final accretion of the Western Cordillera.

  13. Integrating geologic and satellite radar data for mapping dome-and-basin patterns in the In Ouzzal Terrane, Western Hoggar, Algeria

    Science.gov (United States)

    Deroin, Jean-Paul; Djemai, Safouane; Bendaoud, Abderrahmane; Brahmi, Boualem; Ouzegane, Khadidja; Kienast, Jean-Robert

    2014-11-01

    The In Ouzzal Terrane (IOT) located in the north-western part of the Tuareg Shield forms an elongated N-S trending block, more than 400 km long and 80 km wide. It involves an Archaean crust remobilized during a very high-temperature metamorphic event related to the Palaeoproterozoic orogeny. The IOT largely crops out in the rocky and sandy desert of Western Hoggar. It corresponds mainly to a flat area with some reliefs composed of Late Panafrican granites, dyke networks or Cambrian volcanic rocks. These flat areas are generally covered by thin sand veneers. They are favorable for discriminating bedrock geological units using imaging radar, backscattering measurements, and field checking, because the stony desert is particularly sensitive to the radar parameters such as wavelength or polarization. The main radar data used are those obtained with the ALOS-PALSAR sensor (L-band), in ScanSAR mode (large swath) and Fine Beam modes. The PALSAR sensor has been also compared to ENVISAT-ASAR and to optical imagery. Detailed mapping of some key areas indicates extensive Archaean dome-and-basin patterns. In certain parts, the supracrustal synforms and orthogneiss domes exhibit linear or circular features corresponding to shear zones or rolling structures, respectively. The geological mapping of these dome-and-basin structures, and more generally of the Archaean and Proterozoic lithological units, is more accurate with the SAR imagery, particularly when using the L-band, than with the optical imagery. A quantitative approach is carried out in order to estimate the backscatter properties of the main rock types. Due to the large variety of configurations, radar satellite imagery such as ALOS PALSAR represents a key tool for geological mapping in arid region at different scales from the largest (e.g., 1:500,000) to the smallest (e.g., 1:50,000).

  14. Biogeographic patterns of desert springs in the Great Basin with an emphasis on regional aquifer thermal springs as refugia for vulnerable crenobiotic species

    Science.gov (United States)

    Forrest, M.; Sada, D. W.; Norris, R. D.

    2013-12-01

    The desert springs of the Great Basin Region in western North America provide ideal systems to study biogeographic and evolutionary patterns. In arid regions, springs are biodiversity hotspots because they often provide the sole source of water for the biota within and around them. In the Great Basin, springs provide critical habitat for diverse and extensive crenobiotic flora and fauna comprising over 125 endemic species. These aquatic environments represent island ecosystems surrounded by seas of desert, and researchers have compiled large databases of their biota and chemistry. Consequently, desert springs are excellent systems for biogeographic studies and multivariate statistical analyses of relationships between the chemical and physical characteristics of the springs and the biological communities that they support. The purpose of this study is to elucidate the relationships between the physicochemical characteristics of springs and their biota using multivariate statistical analyses to characterize 1325 springs, including regional aquifer springs, local aquifer cold springs and geothermal springs. The analyses reveal that regional aquifer thermal springs harbor disproportionate numbers of crenobiotic species including endemic gastropods, fishes, and aquatic insects. However, these regional aquifer springs also contain significantly more introduced species than cold and geothermal local aquifer springs. Springs are threatened by anthropogenic impacts including groundwater depletion and pollution, alteration of flow regimes, and the introduction of exotic species. In this study, one of the major factors that distinguished regional aquifer thermal springs from cold and geothermal local aquifer springs was the higher number of introduced species found in regional aquifer springs. This may be due to the influences of the same physicochemical characteristics that allow regional aquifer springs to serve as refugia for endemic species--species that are able to gain

  15. [Explore the spatial and temporal patterns of water pollution in the Yincungang canal of the Lake Taihu basin, China].

    Science.gov (United States)

    Yang, Xiao-Ying; Luo, Xing-Zhang; Zheng, Zheng; Fang, Shu-Bo

    2012-09-01

    Two high-density snap-shot samplings were conducted along the Yincungang canal, one important tributary of the Lake Tai, in April (low flow period) and June (high flow period) of 2010. Geostatistical analysis based on the river network distance was used to analyze the spatial and temporal patterns of the pollutant concentrations along the canal with an emphasis on chemical oxygen demand (COD) and total nitrogen (TN). Study results have indicated: (1) COD and TN concentrations display distinctly different spatial and temporal patterns between the low and high flow periods. COD concentration in June is lower than that in April, while TN concentration has the contrary trend. (2) COD load is relatively constant during the period between the two monitoring periods. The spatial correlation structure of COD is exponential for both April and June, and the change of COD concentration is mainly influenced by hydrological conditions. (3) Nitrogen load from agriculture increased significantly during the period between the two monitoring periods. Large amount of chaotic fertilizing by individual farmers has led to the loss of the spatial correlation among the observed TN concentrations. Hence, changes of TN concentration in June are under the dual influence of agricultural fertilizing and hydrological conditions. In the view of the complex hydrological conditions and serious water pollution in the Lake Taihu region, geostatistical analysis is potentially a useful tool for studying the characteristics of pollutant distribution and making predictions in the region. PMID:23243858

  16. Pharmaceutical policy of the Andean sub-region.

    Science.gov (United States)

    1993-01-01

    Senior policy makers and health officials from the Andean countries--Bolivia, Colombia, Ecuador, Peru, and Venezuela--have developed a common pharmaceutical policy. The government's role is to assure availability and equal access to effective, quality, and affordable drugs and to safeguard their proper use. The government cannot delegate this role. The availability and accessibility of drugs gauge quality of health services and are social indicators of justice and equity. The public sector must use drugs from the essential drug list. These drugs are also valuable for the private sector. Drugs must not be treated like other merchandise, because the drug market is susceptible to misuse since the consumer cannot select the drug. Commercial advertising strongly influences prescribing of drugs and their use. The 2 major policy points are that promotion of essential drugs is the best approach from a health viewpoint and promotion of generic drug use is the best commercial alternative. The policy calls for the individual countries to pass a comprehensive drug law that reflects commitment to equity and appropriate use and incorporates standardization mechanisms. Criteria for selecting which drugs are allowed on the market include safety, proven efficacy, risk/benefit ratio, and treating the most common health problems at the lowest possible price. The Andean group is working towards harmonization of national essential drugs lists. To assure quality, health authorities must develop the capacity to enforce regulations when situations arise that threaten individual and community health. Supply, marketing, and logistics activities need to be improved and coordinated between the commercial and public sectors. Drug prices are being distanced from administrative control mechanisms and are going to be determined by a dynamic and well-supplied market. Drug information centers and prescription training are needed to achieve rational use of drugs. A joint pharmaceutical market for

  17. The origin of oriented lakes in the Andean foreland, Parque Nacional Torres del Paine (Chilean Patagonia)

    Science.gov (United States)

    Gonzales, Joseph; Aydin, Atilla

    2008-05-01

    The Parque Nacional Torres Del Paine and surrounding area in the Magallanes foreland basin in Chilean Patagonia is the site for numerous lakes fed by glaciers and rivers in the Andean highlands to the west. The lakes are elongate and have conspicuously systematic orientations. We hypothesize that the origin of the oriented lakes lies in the fault system, composed of a right-lateral strike-slip fault set oriented 58° from north, a left-lateral strike-slip set oriented 87°, and a thrust fault set oriented 167°, that exists within the underlying rocks. To test this hypothesis quantitatively, we determined the shape and orientation of the lakes by fitting each lake with an ellipse of appropriate aspect ratio, and later with multiple ellipses consistent with the composite geometry of some lakes. We then examined the faults in the area in terms of their kinematics, orientation and distribution. The distribution of lake orientations showed three distinct groups which appear to correspond to the three main fault groups. For lakes fitted with multiple ellipses, the difference in means between the right-lateral, left-lateral, and thrust faults and their corresponding groups of lakes are 3.05°, 1.57°, and 5.17°. Using a Kolmogorov-Smirnov (K-S) statistical test to compare the orientations of faults with respect to the lakes suggests that there is not a strongly significant difference between the fault orientations and the corresponding lake groups. These results indicate that the faults have a profound control on the orientation, shape, and distribution of the lakes. We attribute this to faults and their damage zones being weaker and therefore prone to a faster rate of erosion, and to stress perturbations associated with discontinuous faults resulting in localized high density fracturing and surface subsidence. These results have implications for lake and drainage system morphologies in other foreland basins along the Andes and other similar settings.

  18. Sources and the flux pattern of dissolved carbon in rivers of the Yenisey basin draining the Central Siberian Plateau

    International Nuclear Information System (INIS)

    Frequent measurements of dissolved organic (DOC) and inorganic (DIC) carbon concentrations in rivers during snowmelt, the entire ice-free season, and winter were made in five large watersheds (15 000–174 000 km2) of the Central Siberian Plateau (Yenisey River basin). These differ in the degree of continuous permafrost coverage, mean annual air temperature, and the proportion of tundra and forest vegetation. With an annual DOC export from the catchment areas of 2.8–4.7 gC m−2 as compared to an annual DIC export of 1.0–2.8 gC m−2, DOC was the dominant component of terrigenous C released to rivers. There was strong temporal variation in the discharge of DOC and DIC. Like for other rivers of the pan-arctic and boreal zones, snowmelt dominated annual fluxes, being 55–71% for water runoff, 64–82% for DOC and 37–41% for DIC. Likewise, DOC and DIC exhibited also a strong spatial variation in C fluxes, with both dissolved C species decreasing from south to north. The rivers of the southern part of the plateau had the largest flow-weighted DOC concentrations among those previously reported for Siberian rivers, but the smallest flow-weighted DIC concentrations. In the study area, DOC and DIC fluxes were negatively correlated with the distribution of continuous permafrost and positively correlated with mean annual air temperature. A synthesis of literature data shows similar trends from west to east, with an eastward decrease of dissolved C concentrations and an increased proportion of DOC in the total dissolved C flux. It appears that there are two contemporary limitations for river export of terrigenous C across Siberia: (1) low productivity of ecosystems with respect to potentially mobilizable organic C, slow weathering rates with concomitant small formation of bicarbonate, and/or wildfire disturbance limit the pools of organic and inorganic C that can be mobilized for transport in rivers (source-limited), and (2) mobilization of available pools of C is

  19. Resource Utilization Pattern and Development in Hills --A Case for the Pindar Basin of Garhwal Himalaya,India

    Institute of Scientific and Technical Information of China (English)

    Vishwambhar Prasad Sati

    2004-01-01

    Agrarian system is well adapted in Himalayan eeo-system. Hence, the people have adopted the traditional subsistence cereal farming and it becomes the main stay of Himalayan people.About 80 percent of the workable force is attached with agriculture and its allied practices, according to the census of 1991. Although, horticultural farming runs parallel with agriculture, its proportion in terms of land is quite less, resulted in a negligible place in the economy of the region. Human resources, mainly men are attached with national security after recruitment in Army. While, women play a vital and integrated role in maintaining the workable potential in the field of agriculture and are known as backbone of economy. An animal resource implies foremost and wider part in agricultural system and economy as well.Water resources are unutilized yet, while almost all the major rivers of our country are originated from and flowing through this region. Increasing population causes forest resources depletion. The which could not take place due to its remoteness from the main streams of the country. The impact of modern technology with innovation in agricultural system remains impracticable due to unwillingness of people in one hand and on the other hand, adverse geographical conditions like topography, climate etc.which could not permit the uses of modern innovation in the field of agriculture. As for infra-structurally,this region is lacked behind, due to its inaccessibility.While, this region is bestowed with numerous rivers,many places for tourists and pilgrims, and huge forest resources. They might be used evenly in the development processes. The practice of tourism will help for the further development, particularly, in the wake of the newly born state, Uttaranchal. The present paper aims to evaluate the present potentiality of resources and their balanced utilization in the Pindar Basin. A precise study has been done on resource utilization, ecology and environment with

  20. Fluvial basin history in the northeastern Mediterranean region underlies dispersal and speciation patterns in the genus Dugesia (Platyhelminthes, Tricladida, Dugesiidae).

    Science.gov (United States)

    Solà, Eduard; Sluys, Ronald; Gritzalis, Konstantinos; Riutort, Marta

    2013-03-01

    In this study we analyzed the phylogenetic relationships of eastern Mediterranean freshwater planarians of the genus Dugesia, estimated divergence times for the various clades, and correlated their phylogeographic patterns with geological and paleoclimatic events, in order to discover which evolutionary processes have shaped the present-day distribution of these animals. Specimens were collected from freshwater courses and lakes in continental and insular Greece. Genetic divergences and phylogenetic relationships were inferred by using the mitochondrial gene subunit I of cytochrome oxidase (COI) and the nuclear ribosomal internal transcribed spacer-1 (ITS-1) from 74 newly collected individuals from Greece. Divergence time estimates were obtained under a Bayesian framework, using the COI sequences. Two alternative geological dates for the isolation of Crete from the mainland were tested as calibration points. A clear phylogeographic pattern was present for Dugesia lineages in the Eastern Mediterranean. Morphological data, combined with information on genetic divergences, revealed that eight out of the nine known species were represented in the samples, while additional new, and still undescribed species were detected. Divergence time analyses suggested that Dugesia species became isolated in Crete after the first geological isolation of the island, and that their present distribution in the Eastern Mediterranean has been shaped mainly by vicariant events but also by dispersal. During the Messinian salinity crisis these freshwater planarians apparently were not able to cross the sea barrier between Crete and the mainland, while they probably did disperse between islands in the Aegean Sea. Their dependence on freshwater to survive suggests the presence of contiguous freshwater bodies in those regions. Our results also suggest a major extinction of freshwater planarians on the Peloponnese at the end of the Pliocene, while about 2Mya ago, when the current Mediterranean

  1. SENP1, but not fetal hemoglobin, differentiates Andean highlanders with chronic mountain sickness from healthy individuals among Andean highlanders.

    Science.gov (United States)

    Hsieh, Matthew M; Callacondo, David; Rojas-Camayo, Jose; Quesada-Olarte, Jose; Wang, Xunde; Uchida, Naoya; Maric, Irina; Remaley, Alan T; Leon-Velarde, Fabiola; Villafuerte, Francisco C; Tisdale, John F

    2016-06-01

    Chronic mountain sickness (CMS) results from chronic hypoxia. It is unclear why certain highlanders develop CMS. We hypothesized that modest increases in fetal hemoglobin (HbF) are associated with lower CMS severity. In this cross-sectional study, we found that HbF levels were normal (median = 0.4%) in all 153 adult Andean natives in Cerro de Pasco, Peru. Compared with healthy adults, the borderline elevated hemoglobin group frequently had symptoms (headaches, tinnitus, cyanosis, dilatation of veins) of CMS. Although the mean hemoglobin level differed between the healthy (17.1 g/dL) and CMS (22.3 g/dL) groups, mean plasma erythropoietin (EPO) levels were similar (healthy, 17.7 mIU/mL; CMS, 12.02 mIU/mL). Sanger sequencing determined that single-nucleotide polymorphisms in endothelial PAS domain 1 (EPAS1) and egl nine homolog 1 (EGLN1), associated with lower hemoglobin in Tibetans, were not identified in Andeans. Sanger sequencing of sentrin-specific protease 1 (SENP1) and acidic nuclear phosphoprotein 32 family, member D (ANP32D), in healthy and CMS individuals revealed that non-G/G genotypes were associated with higher CMS scores. No JAK2 V617F mutation was detected in CMS individuals. Thus, HbF and other classic erythropoietic parameters did not differ between healthy and CMS individuals. However, the non-G/G genotypes of SENP1 appeared to differentiate individuals with CMS from healthy Andean highlanders. PMID:26952840

  2. The Red de Monitoreo de BosquesAndinos: A communication platform for science and policy in the Andean countries

    Science.gov (United States)

    Baez, S.; Cuesta, F. X.; Malizia, A.; Carilla, J.; Bustamante, M.; Yepes, A.

    2013-05-01

    Colombia to Argentina, some of them monitored since 1990. The initial results indicate that warmer, wetter, and more seasonal forests had higher rates of turnover of individuals, and biomass. Most of these patterns held for both, tropical and subtropical forest plots. The study will be completed in 2013, and will be the first study of forest dynamics and carbon content for the countries in the region. Finally, it is the aim of the Andean Forest Network to bring together scientists and policy-makers interested in research, management and conservation of the Andean forest. The creation of the network and the development of its first two products have been possible thanks to the financial support of the Swiss Agency of International Cooperation (COSUDE) through the CIMA project, the Dutch Technical Agency (GIZ), and the endorsement of the Secretaría General de Naciones (SG-CAN). The coordination of the network is currently held by Selene Báez, at CONDESAN (selene.baez@condesan.org). Please contact us if you need more information or if you are interested in becoming part of the network.

  3. Sequence-stratigraphic frameworks and their palaeogeographic patterns for the Permian Lopingian of the Dianqiangui Basin and its adjacent areas of Southwestern China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Permian Lopingian in the Dianqiangui Basin and its adjacent areas is marked by the coal measures of the Wuchiapingian and the carbonate strata of the Changhsingian stages. For the Lopingian of the Dianqiangui Basin and its adjacent areas,the diversity of sedimentary facies and the obviousness of facies change provide an advantaged condition on a study of sequence stratigraphy. Approximately,the Wuchiapingian stage constitutes a third-order sequence and the Changhsingian stage forms an-other. For the Wuchiapingian stage in the study area,coal-measures were developed on the attached platform and,in addition,a special coal-measure that is composed of both limestone beds and coal beds was also developed in the central part of some isolated platforms. Grain-bank grainstones and packstones were formed on the margin of the attached platform as well as in the windward part of iso-lated platforms. For the Changhsingian stage in the study area,open-platform limestones were formed on the attached platform,while sponge-reef limestones were developed both on the margin of the at-tached platform and on the isolated platforms. The Lopingian Series is a set of basin-facies muddy shales with interbeds of silicalites in the inter-platform basin,which appears a set of the large-thick coarse clastic strata of molasses covering direct the deep-water strata from the Devonian to the Per-mian Yangsingian in the Qinzhou-Fangcheng region in the southern part of the study area. All of these features indicate the complexity of temporal-spatial facies-changes. Sequence-stratigraphic frame-works could be established,which would illustrate two types of facies-changing surfaces and dia-chronisms in the stratigraphic records,based on the combination of both biostratigraphic and chronostratigraphic materials and the regularity reflected by temporal evolutionary succession of sediments as well as spatial distributional patterns of sedimentary facies. Ultimately,features of sedi

  4. Geographic distribution, age pattern and sites of lesions in a cohort of Buruli ulcer patients from the Mapé Basin of Cameroon.

    Science.gov (United States)

    Bratschi, Martin W; Bolz, Miriam; Minyem, Jacques C; Grize, Leticia; Wantong, Fidèle G; Kerber, Sarah; Njih Tabah, Earnest; Ruf, Marie-Thérèse; Mou, Ferdinand; Noumen, Djeunga; Um Boock, Alphonse; Pluschke, Gerd

    2013-01-01

    Buruli ulcer (BU), a neglected tropical disease of the skin, caused by Mycobacterium ulcerans, occurs most frequently in children in West Africa. Risk factors for BU include proximity to slow flowing water, poor wound care and not wearing protective clothing. Man-made alterations of the environment have been suggested to lead to increased BU incidence. M. ulcerans DNA has been detected in the environment, water bugs and recently also in mosquitoes. Despite these findings, the mode of transmission of BU remains poorly understood and both transmission by insects or direct inoculation from contaminated environment have been suggested. Here, we investigated the BU epidemiology in the Mapé basin of Cameroon where the damming of the Mapé River since 1988 is believed to have increased the incidence of BU. Through a house-by-house survey in spring 2010, which also examined the local population for leprosy and yaws, and continued surveillance thereafter, we identified, till June 2012, altogether 88 RT-PCR positive cases of BU. We found that the age adjusted cumulative incidence of BU was highest in young teenagers and in individuals above the age of 50 and that very young children (<5) were underrepresented among cases. BU lesions clustered around the ankles and at the back of the elbows. This pattern neither matches any of the published mosquito biting site patterns, nor the published distribution of small skin injuries in children, where lesions on the knees are much more frequent. The option of multiple modes of transmission should thus be considered. Analyzing the geographic distribution of cases in the Mapé Dam area revealed a closer association with the Mbam River than with the artificial lake. PMID:23785529

  5. Geographic distribution, age pattern and sites of lesions in a cohort of Buruli ulcer patients from the Mape Basin of Cameroon.

    Directory of Open Access Journals (Sweden)

    Martin W Bratschi

    Full Text Available Buruli ulcer (BU, a neglected tropical disease of the skin, caused by Mycobacterium ulcerans, occurs most frequently in children in West Africa. Risk factors for BU include proximity to slow flowing water, poor wound care and not wearing protective clothing. Man-made alterations of the environment have been suggested to lead to increased BU incidence. M. ulcerans DNA has been detected in the environment, water bugs and recently also in mosquitoes. Despite these findings, the mode of transmission of BU remains poorly understood and both transmission by insects or direct inoculation from contaminated environment have been suggested. Here, we investigated the BU epidemiology in the Mapé basin of Cameroon where the damming of the Mapé River since 1988 is believed to have increased the incidence of BU. Through a house-by-house survey in spring 2010, which also examined the local population for leprosy and yaws, and continued surveillance thereafter, we identified, till June 2012, altogether 88 RT-PCR positive cases of BU. We found that the age adjusted cumulative incidence of BU was highest in young teenagers and in individuals above the age of 50 and that very young children (<5 were underrepresented among cases. BU lesions clustered around the ankles and at the back of the elbows. This pattern neither matches any of the published mosquito biting site patterns, nor the published distribution of small skin injuries in children, where lesions on the knees are much more frequent. The option of multiple modes of transmission should thus be considered. Analyzing the geographic distribution of cases in the Mapé Dam area revealed a closer association with the Mbam River than with the artificial lake.

  6. Climate change forces new ecological states in tropical Andean lakes.

    Directory of Open Access Journals (Sweden)

    Neal Michelutti

    Full Text Available Air temperatures in the tropical Andes have risen at an accelerated rate relative to the global average over recent decades. However, the effects of climate change on Andean lakes, which are vital to sustaining regional biodiversity and serve as an important water resource to local populations, remain largely unknown. Here, we show that recent climate changes have forced alpine lakes of the equatorial Andes towards new ecological and physical states, in close synchrony to the rapid shrinkage of glaciers regionally. Using dated sediment cores from three lakes in the southern Sierra of Ecuador, we record abrupt increases in the planktonic thalassiosiroid diatom Discostella stelligera from trace abundances to dominance within the phytoplankton. This unprecedented shift occurs against the backdrop of rising temperatures, changing atmospheric pressure fields, and declining wind speeds. Ecological restructuring in these lakes is linked to warming and/or enhanced water column stratification. In contrast to seasonally ice-covered Arctic and temperate alpine counterparts, aquatic production has not increased universally with warming, and has even declined in some lakes, possibly because enhanced thermal stability impedes the re-circulation of hypolimnetic nutrients to surface waters. Our results demonstrate that these lakes have already passed important ecological thresholds, with potentially far-reaching consequences for Andean water resources.

  7. Evidence of the color pattern variation in populations of Gymnotus pantanal (Gymnotiformes from three streams in the upper Paraná River basin, Brazil

    Directory of Open Access Journals (Sweden)

    Vitor André Frana

    2011-06-01

    Full Text Available Color pattern is an important character in the systematics and alpha-taxonomy of electric fishes of the genus Gymnotus. This paper presents evidence of color variation in populations of G. pantanal found in the streams Jacutinga and Pinheirinho, in the upper Paraná River basin, southern Brazil. Color variations were corroborated for morphological and cytogenetic data. Our results show the importance of integrating morphologic and cytogenetic data in the taxonomy of the Gymnotus species.O padrão de colorido é um caráter muito importante na sistemática e alfa taxonomia de espécies do gênero Gymnotus. O objetivo deste trabalho foi apresentar evidências de variação no padrão de colorido em populações locais de Gymnotus pantanal encontrados nos córregos Jacutinga e Pinheirinho, bacia do alto rio Paraná, sul do Brasil. A variação no padrão de colorido foi corroborada por dados morfológicos e citogenéticos. Nossos resultados demonstram a importância da integração de dados morfológicos e citogenéticos na taxonomia de espécies de Gymnotus.

  8. Social-ecological drivers of multiple ecosystem services: what variables explain patterns of ecosystem services across the Norrström drainage basin?

    Directory of Open Access Journals (Sweden)

    Megan Meacham

    2016-03-01

    Full Text Available In human dominated landscapes many diverse, and often antagonistic, human activities are intentionally and inadvertently determining the supply of various ecosystem services. Understanding how different social and ecological factors shape the availability of ecosystem services is essential for fair and effective policy and management. In this paper, we evaluate how well alternative social-ecological models of human impact on ecosystems explain patterns of 16 ecosystem services (ES across the 62 municipalities of the Norrström drainage basin in Sweden. We test four models of human impact on ecosystems, land use, ecological modernization, ecological footprint, and location theory, and test their ability to predict both individual ES and bundles of ES. We find that different models do best to predict different types of individual ES. Land use is the best model for predicting provisioning services, standing water quality, biodiversity appreciation, and cross-country skiing, while other models work better for the remaining services. However, this range of models is not able to predict some of the cultural ES. ES bundles are predicted worse than individual ES by these models, but provide a clear picture of variation in multiple ecosystem services based on limited information. Based on our results, we offer suggestions on how social-ecological modeling and assessments of ecosystems can be further developed.

  9. Groundwater targeting in a hard-rock terrain using fracture-pattern modeling, Niva River basin, Andhra Pradesh, India

    Science.gov (United States)

    Srinivasa Rao, Y.; Reddy, T. V. K.; Nayudu, P. T.

    2000-09-01

    In hard-rock terrain, due to the lack of primary porosity in the bedrock, joints, fault zones, and weathered zones are the sources for groundwater occurrence and movement. To study the groundwater potential in the hard-rock terrain and drought-prone area in the Niva River basin, southern Andhra Pradesh state, India, Landsat 5 photographic data were used to prepare an integrated hydrogeomorphology map. Larsson's integrated deformation model was applied to identify the various fracture systems, to pinpoint those younger tensile fracture sets that are the main groundwater reservoirs, and to understand the importance of fracture density in groundwater prospecting. N35°-55°E fractures were identified as tensile and N35°-55°W fractures as both tensile and shear in the study area. Apparently, these fractures are the youngest open fractures. Wherever N35°-55°E and N35°-55°W fracture densities are high, weathered-zone thickness is greater, water-table fluctuations are small, and well yields are high. Groundwater-potential zones were delineated and classified as very good, good to very good, moderate to good, and poor. Résumé. Dans les roches de socle, l'absence de porosité primaire dans la roche fait que les fractures, les zones de faille et les zones d'altération sont les sites où l'eau souterraine est présente et s'écoule. Pour étudier le potentiel en eau souterraine dans la région de socle sujette à la sécheresse du bassin de la rivière Niva (sud de l'État d'Andhra Pradesh, Inde), des données photographiques de Landsat 5 ont été utilisées pour préparer une carte hydro-géomorphologique. Le modèle intégré de déformation de Larssons a été mis en œuvre pour identifier les différents systèmes de fractures, pour mettre l'accent sur les ensembles de fractures en extension les plus jeunes qui constituent les principaux réservoirs d'eau souterraine, et pour comprendre l'importance de la densité de fractures pour la prospection de l

  10. Spatial and temporal patterns of surface water quality and ichthyotoxicity in urban and rural river basins in Texas.

    Science.gov (United States)

    Vanlandeghem, Matthew M; Meyer, Matthew D; Cox, Stephen B; Sharma, Bibek; Patiño, Reynaldo

    2012-12-15

    The Double Mountain Fork Brazos River (Texas, USA) consists of North (NF) and South Forks (SF). The NF receives urban runoff and twice-reclaimed wastewater effluent, whereas the SF flows through primarily rural areas. The objective of this study was to determine and compare associations between standard water quality variables and ichthyotoxicity at a landscape scale that included urban (NF) and rural (SF) sites. Five NF and three SF sites were sampled quarterly from March 2008 to March 2009 for specific conductance, salinity, hardness, pH, temperature, and turbidity; and a zebrafish (Danio rerio) embryo bioassay was used to determine ichthyotoxicity. Metal and nutrient concentrations at all sites were also measured in addition to standard water quality variables in spring 2009. Principal component analyses identified hardness, specific conductance, and salinity as the water variables that best differentiate the urban NF (higher levels) from rural SF habitat. Nutrient levels were also higher in the NF, but no landscape scale patterns in metal concentrations were observed. Ichthyotoxicity was generally higher in NF water especially in winter, and multiple regression analyses suggested a positive association between water hardness and ichthyotoxicity. To test for the potential influence of the toxic golden alga (Prymnesium parvum) on overall ichthyotoxicity, a cofactor known to enhance golden alga toxin activity was used in the bioassays. Golden alga ichthyotoxicity was detected in the NF but not the SF, suggesting golden alga may have contributed to overall ichthyotoxicity in the urban but not in the rural system. In conclusion, the physicochemistry of the urban-influenced NF water was conducive to the expression of ichthyotoxicity and also point to water hardness as a novel factor influencing golden alga ichthyotoxicity in surface waters. PMID:22682267

  11. Dietary habits and growth: an urban/rural comparison in the Andean region of Apurimac, Peru

    Directory of Open Access Journals (Sweden)

    Laura Andrissi

    2013-12-01

    Full Text Available INTRODUCTION: The efficacy of interventions against children malnutrition crucially depends on a myriad of factors other than the simple food intake, that must be carefully studied in order to plan a balanced policy. The relation between dietary patterns and growth is at the very heart of the problem, especially in consideration of the fact that dietary pattern involves dimension other than pure caloric intake in its definition. In this work we investigated the relations between dietary pattern and growth comparing children from a rural and a urban area in Andean Peru, in terms of food habits and anthropometric variables to develop a model usable in context interventions against malnutrition. MATERIAL AND METHODS: A sample of 159 children (80 from urban, 79 from rural area, aged from 4 to 120 months (72.7 ± 37.5 SD was collected. The data were investigated by a multidimensional (principal component analysis followed by inferential approach analysis to correlate the different hidden dimensions of both anthropometric and dietary observables. The correlation between these dimensions (in the form of principal components were computed and contrasted with the effects of age and urban/rural environments. RESULTS: Caloric intake and growth were not linearly correlated in our data set. Moreover urban and rural environment were demonstrated to show very different patterns of both dietary and anthropometric variables pointing to the marked effect of dietary habits and demographic composition of the analyzed populations. The relation between malnutrition and overweight was at the same time demonstrated to follow a strict area dependent distribution. DISCUSSION AND CONCLUSION: We gave a proof-of-concept of the non-linear character of the relation between malnutrition (in terms of caloric intake and growth, pointing to the need to calibrate interventions on food pattern and not only quantity to contrast malnutrition effects on growth. The education toward a

  12. Effects of the hydrological cycle on the phycoperiphyton assemblage in an Andean foothill stream in Colombia

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    María I. Ríos-Pulgarín

    2016-03-01

    Full Text Available The Guarinó River is a torrential system that is located in the foothills of the Colombian central Andean mountains that naturally experiences severe hydrological disturbances, which were higher during the Niño-Niña/Southern Oscillation (ENSO between 2007 and 2010. The seasonal and interannual variabilities in the taxonomic composition, richness and density of phycoperiphyton assemblages (ecological descriptors from the Guarinó River were examined in relation to the physical and chemical environmental changes associated with the hydrological cycle between 2007 and 2010. The values of the ecological descriptors and environmental variables were analysed via ANOVA, ANCOVA and Canonical Discriminant Analysis to establish temporal patterns and relationships between the variables. Eighty-seven taxa belonging to Cyanobacteria, Chlorophyta, Charophyta, Ochrophyta, Cryptophyta, Euglenozoa and Dinophyta were identified. Flow, water temperature and dissolved oxygen corresponded with the hydroclimatic variation and allowed for the differentiation of the El Niño and La Niña periods. Phycoperiphyton density differences matched the environmental variation pattern with a significant annual increase in the number of individuals during El Niño, whereas annual differences related to richness were not evident. The replacement of genera according to their drag or desiccation tolerance and the persistence of genera tolerant to high hydrological disturbances, such as Fragilaria, Nitzschia, Gomphonema, Navicula and especially Lyngbya, was observed.

  13. The evolution of witchcraft and the meaning of healing in colonial Andean society.

    Science.gov (United States)

    Silverblatt, I

    1983-12-01

    This paper explores the ways in which traditional beliefs of Andean peoples regarding health and sickness were transformed by the process of Spanish colonization. It also examines how the colonial context devolved new meanings and powers on native curers. The analysis of these transformations in Andean systems of meanings and role structures relating to healing depends on an examination of the European witchcraze of the 16th-17th centuries. The Spanish conquest of the Inca empire in the mid-1500's coincided with the European witch hunts; it is argued that the latter formed the cultural lens through which the Spanish evaluated native religion--the matrix through which Andean concepts of disease and health were expressed--as well as native curers. Andean religion was condemned as heresy and curers were condemned as witches. Traditional Andean cosmology was antithetical to 16th century European beliefs in the struggle between god and the devil, between loyal Christians and the Satan's followers. Consequently, European concepts of disease and health based on the power of witches, Satan's adherents, to cause harm and cure were alien to pre-Columbian Andean thought. Ironically European concepts of Satan and the supposed powers of witches began to graft themselves onto the world view of Andean peoples. The ensuing dialectic of ideas as well as the creation of new healers/witches forged during the imposition of colonial rule form the crux of this analysis. PMID:6362989

  14. Detrital and volcanic zircon U-Pb ages from southern Mendoza (Argentina): An insight on the source regions in the northern part of the Neuquén Basin

    Science.gov (United States)

    Naipauer, Maximiliano; Tapia, Felipe; Mescua, José; Farías, Marcelo; Pimentel, Marcio M.; Ramos, Victor A.

    2015-12-01

    The infill of the Neuquén Basin recorded the Meso-Cenozoic geological and tectonic evolution of the southern Central Andes being an excellent site to investigate how the pattern of detrital zircon ages varies trough time. In this work we analyze the U-Pb (LA-MC-ICP-MS) zircon ages from sedimentary and volcanic rocks related to synrift and retroarc stages of the northern part of the Neuquén Basin. These data define the crystallization age of the synrift volcanism at 223 ± 2 Ma (Cerro Negro Andesite) and the maximum depositional age of the original synrift sediments at ca. 204 Ma (El Freno Formation). Two different pulses of rifting could be recognized according to the absolute ages, the oldest developed during the Norian and the younger during the Rhaetian-Sinemurian. The source regions of the El Freno Formation show that the Choiyoi magmatic province was the main source rock of sediment supply. An important amount of detrital zircons with Triassic ages was identified and interpreted as a source area related to the synrift magmatism. The maximum depositional age calculated for the Tordillo Formation in the Atuel-La Valenciana depocenter is at ca. 149 Ma; as well as in other places of the Neuquén Basin, the U-Pb ages calculated in the Late Jurassic Tordillo Formation do not agree with the absolute age of the Kimmeridgian-Tithonian boundary (ca. 152 Ma). The main source region of sediment in the Tordillo Formation was the Andean magmatic arc. Basement regions were also present with age peaks at the Carboniferous, Neoproterozoic, and Mesoproterozoic; these regions were probably located to the east in the San Rafael Block. The pattern of zircon ages summarized for the Late Jurassic Tordillo and Lagunillas formations were interpreted as a record of the magmatic activity during the Triassic and Jurassic in the southern Central Andes. A waning of the magmatism is inferred to have happened during the Triassic. The evident lack of ages observed around ca. 200 Ma suggests

  15. Analysis of the drought resilience of Andosols on southern Ecuadorian Andean páramos

    OpenAIRE

    Iñiguez, V.; O. Morales; Cisneros, F; Bauwens, W; Wyseure, G.

    2015-01-01

    The neotropical Andean grasslands above 3500 m a.s.l. known as "páramo" offer remarkable ecological services for the Andean region. Most important is the water supply – of excellent quality – to many cities and villages established in the lowlands of the inter-Andean valleys and to the coast. However, the páramo ecosystem is under constant and increased threat by human activities and climate change. In this paper we study the resilience of its soils for drou...

  16. Geometry of the inverted Cretaceous Chañarcillo Basin based on 2-D gravity and field data. An approach to the structure of the western Central Andes of northern Chile

    Directory of Open Access Journals (Sweden)

    F. Martínez

    2015-08-01

    Full Text Available This paper discusses an integrated approach that provides new ideas about the structural geometry of the NNE-striking, Cretaceous Chañarcillo Basin located along the eastern Coastal Cordillera in the western Central Andes of northern Chile (27–28° S. The results obtained from the integration of two transverse (E–W gravity profiles with previous geological information, show that the architecture of this basin is defined by a large NNE–SSE-trending and east-vergent anticline ("Tierra Amarilla Anticlinorium", which is related to the positive reactivation of a former Cretaceous normal fault (Elisa de Bordos Master Fault. Moreover, intercalations of high and low gravity anomalies and steep gravity gradients reveal a set of buried, west-tilted half-grabens associated with a synthetic normal fault pattern. These results, together with the uplift and folding style of the Cretaceous syn-rift recognized within the basin, suggest that their complete structural geometry could be explained by an inverted fault system linked to the shortening of pre-existing Cretaceous normal fault systems. Ages of the synorogenic deposits exposed unconformably over the frontal limb of the Tierra Amarilla Anticlinorium confirm a Late Cretaceous age for the Andean deformation and tectonic inversion of the basin.

  17. Validation of Satellite Precipitation (trmm 3B43) in Ecuadorian Coastal Plains, Andean Highlands and Amazonian Rainforest

    Science.gov (United States)

    Ballari, D.; Castro, E.; Campozano, L.

    2016-06-01

    Precipitation monitoring is of utmost importance for water resource management. However, in regions of complex terrain such as Ecuador, the high spatio-temporal precipitation variability and the scarcity of rain gauges, make difficult to obtain accurate estimations of precipitation. Remotely sensed estimated precipitation, such as the Multi-satellite Precipitation Analysis TRMM, can cope with this problem after a validation process, which must be representative in space and time. In this work we validate monthly estimates from TRMM 3B43 satellite precipitation (0.25° x 0.25° resolution), by using ground data from 14 rain gauges in Ecuador. The stations are located in the 3 most differentiated regions of the country: the Pacific coastal plains, the Andean highlands, and the Amazon rainforest. Time series, between 1998 - 2010, of imagery and rain gauges were compared using statistical error metrics such as bias, root mean square error, and Pearson correlation; and with detection indexes such as probability of detection, equitable threat score, false alarm rate and frequency bias index. The results showed that precipitation seasonality is well represented and TRMM 3B43 acceptably estimates the monthly precipitation in the three regions of the country. According to both, statistical error metrics and detection indexes, the coastal and Amazon regions are better estimated quantitatively than the Andean highlands. Additionally, it was found that there are better estimations for light precipitation rates. The present validation of TRMM 3B43 provides important results to support further studies on calibration and bias correction of precipitation in ungagged watershed basins.

  18. Measurements and modelling of evapotransiration to assess agricultural water productivity in basins with changing land use patterns : a case study in the São Francisco River basin, Brazil

    OpenAIRE

    Castro Teixeira, de, A.H.

    2008-01-01

    Key words: Vineyards, mango, energy balance, evapotranspiration, water productivity, Bowen ratio, eddy correlation, water balance, natural vegetation, latent heat flux, sensible heat flux, biomass, water productivity, remote sensing, water management. . The São Francisco River basin in Brazil is marked by socio-eco¬nomic disparities and environmental vulnerabilities. Water managers in the semi-arid region of the basin are faced with several challenges, such as competition among different wate...

  19. The Salar de Atacama Basin: a Subsiding Block within the Western Edge of the Altiplano-Puna Plateau

    OpenAIRE

    Klaus-J. Reutter; Reynaldo Charrier; Hans-J. Götze; B. Schurr; Peter Wigger; Ekkehard Scheuber; Peter Giese; Claus-Dieter Reuther; Sabine Schmidt; Andreas Rietbrock; Guillermo Chong; Arturo Belmonte-Pool

    2006-01-01

    The internally drained Salar de Atacama (SdA) Basin, located in the proximal fore-arc between the present magmatic arc (Western Cordillera) to the east and the North Chilean Precordillera (Cordillera de Domeyko) to the west, represents a prominent morphological anomaly in the Central Andean Plateau. The basin is a post-Incaic feature that developed contemporaneously with the initial plateau uplift. Before 38 Ma, the magmatic arc was positioned in the present-day Precordillera; as a result, th...

  20. An Outbreak of Bartonella bacilliformis in an Endemic Andean Community

    Science.gov (United States)

    Sanchez Clemente, Nuria; Ugarte-Gil, Cesar; Solorzano, Nelson; Maguiña, Ciro; Moore, David

    2016-01-01

    Background Bartonellosis affects small Andean communities in Peru, Colombia and Ecuador. Research in this area has been limited. Methods Retrospective review of 191 cases of bartonellosis managed in Caraz District Hospital, Peru, during the last outbreak (2003). Results The majority of cases (65%) were 14 years old and younger. There was a peak in acute cases after the rainy season; chronic cases presented more constantly throughout the year. The sensitivity of blood smear against blood culture in acute disease was 25%. The most commonly used treatment for chronic disease was rifampicin; chloramphenicol was used to treat most acute cases. Complications arose in 6.8% and there were no deaths. Conclusions Diagnostic and treatment algorithms for acute and chronic bartonellosis have been developed without a strong evidence base. Preparation of ready-to-go operational research protocols for future outbreaks would strengthen the evidence base for diagnostic and treatment strategies and enhance opportunities for control. PMID:26991495

  1. Music, movements and colors in Andean fiesta. Bolivian examples

    Directory of Open Access Journals (Sweden)

    Rosalía Martínez

    2015-01-01

    Full Text Available In the Andean fiesta music is as much intended to be seen as it is to be heard. The multisensorial aspect of musical performance is not just a matter of the juxtaposition of sounds and sights. The analysis of the articulations that indigenous peasants of sucre (Bolivia construct among sounds, movements and colors reveals an original organization of sensitive experience that is as much characterized by its sensory depth as it is by the ways it is linked to other domains of knowledge. The forms of culturally elaborated intersections that occur in the body of the musician lead to new perceptive configurations.

  2. A new minute Andean Pristimantis (Anura: Strabomantidae from Venezuela

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    César L. Barrio-Amorós

    2012-12-01

    Full Text Available A new species of Pristimantis is described from the Venezuelan Andes. The new species is the smallest in its genus known in Venezuela and belongs to the Pristimantis unistrigatus Group. It differs from the rest of Venezuelan Andean congeners in body size (mean male SVL < 21.3 mm, female SVL < 26.3 mm, expanded discs on fingers and toes, absence of dorsolateral folds, and a distinctivecall consisting in 2–5 cricket-like short notes. The new species inhabits the southwestern part of the Cordillera de Mérida in Venezuela and the Venezuelan side of the Cordillera Oriental deColombia, and could be present on the Colombian portion of the cordillera as well.

  3. [Elaboration and evaluation of infant food based on Andean crops].

    Science.gov (United States)

    Repo-Carrasco, R; Hoyos, N L

    1993-06-01

    The Andes mountain range of South America is one of the most important centres for crop domestication, potato, corn, and lesser known grains such as quinua, cañihua, kiwicha and tarwi are indigenous of these highlands. These Andean grains have adapted perfectly to the climatic and geographical conditions present, whereas other grains have not been able to survive. In addition to their hardiness, they also have a high nutritional value. Bearing in mind on one hand, the high nutritional value of these indegenous products, and on the other hand the high rate of child malnutrition prevalent in the population, it was considered important to look for new variations in their processing which would facilitate their consumption by the poor working classes, especially the children. Accordingly three different flour mixtures were developed based on these Andean grains, the mixtures were then subjected to bromatological and biological analysis. The three new flour mixtures were: Quinua-Cañihua-Broad Bean (Q-C-B), Quinua-Kiwicha-Bean (Q-K-B) and Kiwicha-Rice (K-R). The protein content of these mixtures varied between 11.35-15.46 g/100g, the mixture K-R having the lowest protein level and the Q-C-B having the highest. The Q-K-B mixture had the highest chemical score, PER and NPU value. This PER value of 2.59 was higher than the value of casein which was 2.50. In addition this mixture had a chemical score of 0.94 and a NPU value of 59.38. The Q-C-B mixture had a chemical score of 0.88 and its PER, NPU and Digestibility values were 2.36, 47.24 and 79.2 respectively.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7826191

  4. Watershed-based natural research management: Lessons from projects in the Andean region

    OpenAIRE

    Sowell, A.R.

    2009-01-01

    This Undergraduate Honors Thesis focuses on how different factors affect the success of a watershed management project and lessons learned from projects in the Andean Region. LTRA-3 (Watershed-based NRM for Small-scale Agriculture)

  5. Farmers' participation and breeding for durable disease resistance in the Andean region

    NARCIS (Netherlands)

    Danial, D.L.; Parlevliet, J.E.; Almekinders, C.J.M.; Thiele, G.

    2007-01-01

    In the Andean region, the Preduza project and its partners combined breeding for durable disease resistance using locally adapted cultivars and farmer participatory methods. The approach taken resembles participatory variety selection (PVS). Farmers participated in the selection of advanced material

  6. Wind tunnel experiments of air flow patterns over nabkhas modeled after those from the Hotan River basin,Xinjiang,China(Ⅰ):non-vegetated

    Institute of Scientific and Technical Information of China (English)

    Zhizhong LI; Wanjuan LI; Shengli WU; Janis DALE; Lin GE; Mudan HE; Xiaofeng WANG; Jianhui JIN; Rong MA; Jinwei LIU

    2008-01-01

    A nabkha is a vegetated sand mound,which is ypical of the aeolian landforms found in the Hotan River pasin in Xinjiang,China.This paper compares the results of a series of wind tunnel experiments with an on-site field survey of nabkhas in the Hotan River basin of Xinjiang.Wind tunnel experiments were conducted on semi-sphercal and conical sand mounds without vegetation or shadow dunes.Field mounds were 40 times as large as the size of the wind tunnel models.In the wind tunnel experiments,five different velocities from 6 to 14 m/s were selected and used to model the wind flow pattern over mdividual sand mound using clean air without additional sand.Changes in the flow pattern at different wind speeds resulted in changes to the characteristic structure of the babkha surface.The results of the experiments for the semi-spherical sand mound at all wind velocities show the formation of a vortex at the bottom of the upwind side of the mound that resulted in scouring and deposition of a crescentic dune upwind of the main mound.The top part of the sand mound is strongly eroded.In the field,these dunes exhibited the same scouring and crescentic dune formation and the eroded upper surface was often topped by a layer of peat within the mound suggesting destroyed vegetation due to river channel migration or by possible anthropogenic forces such as fuel gathering,etc.Experiments for the conical mounds exhibit only a small increase in velocity on the upwind side of the mound and no formation of a vortex at the bottom of the upwind side.Instead,a vortex formed on the leeward side of the mound and overall,no change occurred in the shape of the conical mound.In the field,conical mounds have no crescentic dunes on the upwind side and no erosion at the top exposed below peat beds.Therefore,the field and laboratory experiments show that semi-spherical and conical sand mounds respond differently to similar wind conditions with different surface configuration and development of crescent

  7. Controls on timing of exhumation and deformation in the northern Peruvian eastern Andean wedge as inferred from low-temperature thermochronology and balanced cross section

    Science.gov (United States)

    Eude, Adrien; Roddaz, Martin; Brichau, Stéphanie; Brusset, Stéphane; Calderon, Ysabel; Baby, Patrice; Soula, Jean-Claude

    2015-04-01

    In northern Peru, a 500 km long regional balanced section has been constructed across the eastern Andean wedge, using fieldwork, industrial seismic sections, and wells. The structure is characterized by a thin-skinned thrust system involving the Eastern Cordillera (EC), the sub-Andean zone (SAZ), and the Marañón foredeep. In the SAZ and the easternmost foredeep the development of the thrust system has been driven by the combination of two structural events. Permian thrust faults had been reactivated to form a basement duplex underlying the SAZ and the foredeep. At the same time a Triassic-Jurassic extensional basin has been transported as a crustal ramp anticline on to the duplex roof fault, giving rise to the EC. The impingement of the EC was responsible for the deformation of the SAZ and the propagation of the thrust wedge. The minimum shortening calculated is 142 km, representing a shortening strain of ~ -28%. A sequential restoration calibrated by (U-Th)/He and Fission Track dating on apatites and vitrinite reflectance values shows that shortening rates vary from 7.1 mm yr-1 between 17 and 8 Ma to 3.6 mm yr-1 between 8 Ma and today and suggests that the thrust wedge commenced propagation between 30 and 24 Ma. When compared with other Andean thrust wedges, we suggest that the timing of the thrust wedge propagation is not a simple function of the distance to the hinge of the Bolivian orocline and the propagation is not controlled by the precipitation regime. We rather suggest that reactivated basement faults favored thrust wedge propagation.

  8. Contribution of a mutational hot spot to hemoglobin adaptation in high-altitude Andean house wrens.

    Science.gov (United States)

    Galen, Spencer C; Natarajan, Chandrasekhar; Moriyama, Hideaki; Weber, Roy E; Fago, Angela; Benham, Phred M; Chavez, Andrea N; Cheviron, Zachary A; Storz, Jay F; Witt, Christopher C

    2015-11-10

    A key question in evolutionary genetics is why certain mutations or certain types of mutation make disproportionate contributions to adaptive phenotypic evolution. In principle, the preferential fixation of particular mutations could stem directly from variation in the underlying rate of mutation to function-altering alleles. However, the influence of mutation bias on the genetic architecture of phenotypic evolution is difficult to evaluate because data on rates of mutation to function-altering alleles are seldom available. Here, we report the discovery that a single point mutation at a highly mutable site in the β(A)-globin gene has contributed to an evolutionary change in hemoglobin (Hb) function in high-altitude Andean house wrens (Troglodytes aedon). Results of experiments on native Hb variants and engineered, recombinant Hb mutants demonstrate that a nonsynonymous mutation at a CpG dinucleotide in the β(A)-globin gene is responsible for an evolved difference in Hb-O2 affinity between high- and low-altitude house wren populations. Moreover, patterns of genomic differentiation between high- and low-altitude populations suggest that altitudinal differentiation in allele frequencies at the causal amino acid polymorphism reflects a history of spatially varying selection. The experimental results highlight the influence of mutation rate on the genetic basis of phenotypic evolution by demonstrating that a large-effect allele at a highly mutable CpG site has promoted physiological differentiation in blood O2 transport capacity between house wren populations that are native to different elevations. PMID:26460028

  9. Behavior patterns and fates of adult steelhead, Chinook salmon, and coho salmon released into the upper Cowlitz River Basin, 2005–09 and 2012, Washington

    Science.gov (United States)

    Kock, Tobias J.; Ekstrom, Brian K.; Liedtke, Theresa L.; Serl, John D.; Kohn, Mike

    2016-01-01

    A multiyear radiotelemetry evaluation was conducted to monitor adult steelhead (Oncorhynchus mykiss), Chinook salmon (O. tshawytscha), and coho salmon (O. kisutch) behavior and movement patterns in the upper Cowlitz River Basin. Volitional passage to this area was eliminated by dam construction in the mid-1960s, and a reintroduction program began in the mid-1990s. Fish are transported around the dams using a trap-and-haul program, and adult release sites are located in Lake Scanewa, the uppermost reservoir in the system, and in the Cowlitz and Cispus Rivers. Our goal was to estimate the proportion of tagged fish that fell back downstream of Cowlitz Falls Dam before the spawning period and to determine the proportion that were present in the Cowlitz and Cispus Rivers during the spawning period. Fallback is important because Cowlitz Falls Dam does not have upstream fish passage, so fish that pass the dam are unable to move back upstream and spawn. A total of 2,051 steelhead and salmon were tagged for the study, which was conducted during 2005–09 and 2012, and 173 (8.4 percent) of these regurgitated their transmitter prior to, or shortly after release. Once these fish were removed from the dataset, the final number of fish that was monitored totaled 1,878 fish, including 647 steelhead, 770 Chinook salmon, and 461 coho salmon.Hatchery-origin (HOR) and natural-origin (NOR) steelhead, Chinook salmon, and coho salmon behaved differently following release into Lake Scanewa. Detection records showed that the percentage of HOR fish that moved upstream and entered the Cowlitz River or Cispus River after release was relatively low (steelhead = 38 percent; Chinook salmon = 67 percent; coho salmon = 41 percent) compared to NOR fish (steelhead = 84 percent; Chinook salmon = 82 percent; coho salmon = 76 percent). The elapsed time from release to river entry was significantly lower for NOR fish than for HOR fish for all three species. Tagged fish entered the Cowlitz River in

  10. Diversity of Andean amphibians of the Tamá National Natural Park in Colombia: a survey for the presence of Batrachochytrium dendrobatidis

    OpenAIRE

    Acevedo, A. A.; R. de Franco; Carrero, D. A.

    2016-01-01

    Changes in diversity and possible decreases in populations of amphibians have not yet been determined in many areas in the Andes. This study aimed to develop an inventory of the biodiversity of amphibians in the Andean areas of the Tamá National Natural Park (Tamá NNP) and to evaluate the patterns of infection by Batrachochytrium dendrobatidis (Bd) in preserved and degraded areas. We performed samplings focused on three habitats (forest, open areas and streams) in four localities from 2,000 t...

  11. Birds of Two Oceans? Trans-Andean and Divergent Migration of Black Skimmers (Rynchops niger cinerascens from the Peruvian Amazon.

    Directory of Open Access Journals (Sweden)

    Lisa C Davenport

    Full Text Available Seasonal flooding compels some birds that breed in aquatic habitats in Amazonia to undertake annual migrations, yet we know little about how the complex landscape of the Amazon region is used seasonally by these species. The possibility of trans-Andes migration for Amazonian breeding birds has largely been discounted given the high geographic barrier posed by the Andean Cordillera and the desert habitat along much of the Pacific Coast. Here we demonstrate a trans-Andes route for Black Skimmers (Rynchops niger cinerascens breeding on the Manu River (in the lowlands of Manu National Park, Perú, as well as divergent movement patterns both regionally and across the continent. Of eight skimmers tracked with satellite telemetry, three provided data on their outbound migrations, with two crossing the high Peruvian Andes to the Pacific. A third traveled over 1800 km to the southeast before transmissions ended in eastern Paraguay. One of the two trans-Andean migrants demonstrated a full round-trip migration back to its tagging location after traveling down the Pacific Coast from latitude 9° South to latitude 37° S, spending the austral summer in the Gulf of Arauco, Chile. This is the first documentation of a trans-Andes migration observed for any bird breeding in lowland Amazonia. To our knowledge, this research also documents the first example of a tropical-breeding waterbird migrating out of the tropics to spend the non-breeding season in the temperate summer, this being the reverse pattern with respect to seasonality for austral migrants in general.

  12. Birds of Two Oceans? Trans-Andean and Divergent Migration of Black Skimmers (Rynchops niger cinerascens) from the Peruvian Amazon.

    Science.gov (United States)

    Davenport, Lisa C; Goodenough, Katharine S; Haugaasen, Torbjørn

    2016-01-01

    Seasonal flooding compels some birds that breed in aquatic habitats in Amazonia to undertake annual migrations, yet we know little about how the complex landscape of the Amazon region is used seasonally by these species. The possibility of trans-Andes migration for Amazonian breeding birds has largely been discounted given the high geographic barrier posed by the Andean Cordillera and the desert habitat along much of the Pacific Coast. Here we demonstrate a trans-Andes route for Black Skimmers (Rynchops niger cinerascens) breeding on the Manu River (in the lowlands of Manu National Park, Perú), as well as divergent movement patterns both regionally and across the continent. Of eight skimmers tracked with satellite telemetry, three provided data on their outbound migrations, with two crossing the high Peruvian Andes to the Pacific. A third traveled over 1800 km to the southeast before transmissions ended in eastern Paraguay. One of the two trans-Andean migrants demonstrated a full round-trip migration back to its tagging location after traveling down the Pacific Coast from latitude 9° South to latitude 37° S, spending the austral summer in the Gulf of Arauco, Chile. This is the first documentation of a trans-Andes migration observed for any bird breeding in lowland Amazonia. To our knowledge, this research also documents the first example of a tropical-breeding waterbird migrating out of the tropics to spend the non-breeding season in the temperate summer, this being the reverse pattern with respect to seasonality for austral migrants in general. PMID:26760301

  13. Patterns of Larval Sucker Emigration from the Sprague and Lower Williamson Rivers of the Upper Klamath Basin, Oregon, Prior to the Removal of Chiloquin Dam - 2006 Annual Report

    Science.gov (United States)

    Ellsworth, Craig M.; Tyler, Torrey J.; VanderKooi, Scott P.; Markle, Douglas F.

    2009-01-01

    in larval drift at Chiloquin occurred approximately 1.5 to 2.0 hours after sunset. Nightly peak larval drift varied by location; larvae were captured earlier in the evening at sites closer to known spawning locations than sites farther away from these areas. The highest numerical catches of sucker-sized eggs were at Chiloquin indicating that this site is in close proximity to a spawning area. Numerical catches of older, more developed larval and juvenile suckers also were highest at Chiloquin. This may be due to the turbulent nature of this site, which could have swept larger fish into the drift. Proportional catches of older, more developed larval and juvenile suckers were highest at Sycan, Lone Pine, Power Station, and Fremont Bridge. This indicates these sites are located nearer to sucker nursery areas rather than spawning areas. Very few larval LRS were collected at Fremont Bridge at the south end of Upper Klamath Lake. Larval KLS-SNS densities at Fremont Bridge were the third highest of the seven sampling sites. Peak drift of larval KLS-SNS at Fremont Bridge occurred the week after peak drift of larval KLS-SNS at Williamson. Although inter-annual variation continues to appear in the larval drift data, our results continue to show consistent patterns of larval emigration in the drainage basin. In combination with data collected from the spawning movements and destinations of radio-tagged and PIT-tagged adult suckers, this larval drift data will provide a baseline standard by which to determine the effects of dam removal on the spawning distribution of endangered Klamath Basin suckers in the Sprague River.

  14. Spatial gradients pattern of landscapes and their relations with environmental factors in Haihe River basin%海河流域景观空间梯度格局及其与环境因子的关系

    Institute of Scientific and Technical Information of China (English)

    赵志轩; 张彪; 金鑫; 翁白莎; 严登华; 鲍淑君

    2011-01-01

    The spatial pattern and dynamic evolution of the landscape are jointly influenced by its physical environment,animals and vegetations and human activities on a basin scale. Physical environmental factors including the elevation,climate, hydrology and soil constitute the backdrop of the general landscape pattern formation and evolution. Biological processes exert a significant impact on patch features on a small scale. Human activities, including population growth,economic development and policy factors, play their due roles on any scale.Landscape pattern analysis, a basis of further researches on landscape functions and dynamics, contributes to analyzing spatial distribution characteristics of landscape components in a quantitative manner. During recent years, great developments have been made on researches about indices and models of landscape pattern evolution in a quantitative way.However, little has been known about gradient patterns and its relationship with environmental factors on a basin scale.Gradient analysis, which is conducive to revealing driving forces behind landscape evolutionary processes, can reflect the evolutionary laws of spatial landscape patterns. At present, there is still lack of systematic studies on selections among diversified transects and their reflected differences of calculation results of landscape gradient patterns.During the past two decades, tremendous changes have taken place in its landscape patterns in Haihe River basin.This paper, taking Haihe River Basin as its study area and based on GIS ( Geographic Information System) technologies,aims to analyze complete landscape patterns and its spatial differences within the whole basin through standard methods and moving window analysis of Fragstats3.3, and to investigate the relationships between the landscape gradient pattern and environmental factors through detrended canonical correspondence analysis (DCCA); to obtain gradient patterns of the landscapes, two transects which have

  15. Measurements and modelling of evapotransiration to assess agricultural water productivity in basins with changing land use patterns : a case study in the São Francisco River basin, Brazil

    NARCIS (Netherlands)

    Castro Teixeira, de A.H.

    2008-01-01

    Key words: Vineyards, mango, energy balance, evapotranspiration, water productivity, Bowen ratio, eddy correlation, water balance, natural vegetation, latent heat flux, sensible heat flux, biomass, water productivity, remote sensing, water management. . The São Francisco River basin in Brazil is m

  16. Small mammal distributional patterns in Northwestern Argentina

    Directory of Open Access Journals (Sweden)

    María L. Sandoval

    2015-12-01

    Full Text Available ABSTRACT Quantitative evaluations of species distributional congruence allow evaluating previously proposed biogeographic regionalization and even identify undetected areas of endemism. The geographic scenery of Northwestern Argentina offers ideal conditions for the study of distributional patterns of species since the boundaries of a diverse group of biomes converge in a relatively small region, which also includes a diverse fauna of mammals. In this paper we applied a grid-based explicit method in order to recognize Patterns of Distributional Congruence (PDCs and Areas of Endemism (AEs, and the species (native but non-endemic and endemic, respectively that determine them. Also, we relate these distributional patterns to traditional biogeographic divisions of the study region and with a very recent phytogeographic study and we reconsider what previously rejected as 'spurious' areas. Finally, we assessed the generality of the patterns found. The analysis resulted in 165 consensus areas, characterized by seven species of marsupials, 28 species of bats, and 63 species of rodents, which represents a large percentage of the total species (10, 41, and 73, respectively. Twenty-five percent of the species that characterize consensus areas are endemic to the study region and define six AEs in strict sense while 12 PDCs are mainly defined by widely distributed species. While detailed quantitative analyses of plant species distribution data made by other authors does not result in units that correspond to Cabrera's phytogeographic divisions at this spatial scale, analyses of animal species distribution data does. We were able to identify previously unknown meaningful faunal patterns and more accurately define those already identified. We identify PDCs and AEs that conform Eastern Andean Slopes Patterns, Western High Andes Patterns, and Merged Eastern and Western Andean Slopes Patterns, some of which are re-interpreted at the light of known patterns of the

  17. Broad-scale sampling of primary freshwater fish populations reveals the role of intrinsic traits, inter-basin connectivity, drainage area and latitude on shaping contemporary patterns of genetic diversity.

    Science.gov (United States)

    Sousa-Santos, Carla; Robalo, Joana I; Pereira, Ana M; Branco, Paulo; Santos, José Maria; Ferreira, Maria Teresa; Sousa, Mónica; Doadrio, Ignacio

    2016-01-01

    Background. Worldwide predictions suggest that up to 75% of the freshwater fish species occurring in rivers with reduced discharge could be extinct by 2070 due to the combined effect of climate change and water abstraction. The Mediterranean region is considered to be a hotspot of freshwater fish diversity but also one of the regions where the effects of climate change will be more severe. Iberian cyprinids are currently highly endangered, with over 68% of the species raising some level of conservation concern. Methods. During the FISHATLAS project, the Portuguese hydrographical network was extensively covered (all the 34 river basins and 47 sub-basins) in order to contribute with valuable data on the genetic diversity distribution patterns of native cyprinid species. A total of 188 populations belonging to 16 cyprinid species of Squalius, Luciobarbus, Achondrostoma, Iberochondrostoma, Anaecypris and Pseudochondrostoma were characterized, for a total of 3,678 cytochrome b gene sequences. Results. When the genetic diversity of these populations was mapped, it highlighted differences among populations from the same species and between species with identical distribution areas. Factors shaping the contemporary patterns of genetic diversity were explored and the results revealed the role of latitude, inter-basin connectivity, migratory behaviour, species maximum size, species range and other species intrinsic traits in determining the genetic diversity of sampled populations. Contrastingly, drainage area and hydrological regime (permanent vs. temporary) seem to have no significant effect on genetic diversity. Species intrinsic traits, maximum size attained, inter-basin connectivity and latitude explained over 30% of the haplotype diversity variance and, generally, the levels of diversity were significantly higher for smaller sized species, from connected and southerly river basins. Discussion. Targeting multiple co-distributed species of primary freshwater fish allowed

  18. Changing Hydrology in Glacier-fed High Altitude Andean Peatbogs

    Science.gov (United States)

    Slayback, D. A.; Yager, K.; Baraer, M.; Mohr, K. I.; Argollo, J.; Wigmore, O.; Meneses, R. I.; Mark, B. G.

    2012-12-01

    Montane peatbogs in the glacierized Andean highlands of Peru and Bolivia provide critical forage for camelids (llama and alpaca) in regionally extensive pastoral agriculture systems. During the long dry season, these wetlands often provide the only available green forage. A key question for the future of these peatbog systems, and the livelihoods they support, is the impact of climate change and glacier recession on their hydrology, and thus forage production. We have already documented substantial regional glacier recession, of, on average, approximately 30% of surface area over the past two decades. As glaciers begin to retreat under climate change, there is initially a period of increased meltwater outflow, culminating in a period of "peak water", and followed by a continual decline in outflows. Based on previous work, we know that some glaciers in the region have already passed peak water conditions, and are now declining. To better understand the impacts of these processes on peatbog hydrology and productivity, we have begun collecting a variety of surface data at several study sites in both Bolivia and Peru. These include precipitation, stream flow, water levels, water chemistry and isotope analyses, and peatbog biodiversity and biomass. These measurements will be used in conjunction with a regional model driven by satellite data to predict likely future impacts. We will present the results from these initial surface measurements, and an overview of satellite datasets to be used in the regional model.

  19. Storage of carbon in natural grasses high andean

    Directory of Open Access Journals (Sweden)

    Raúl Marino Yaranga Cano

    2013-12-01

    Full Text Available The aim of the study was to determine the capacity of storage of carbon in species of grasses natural of high andean, between January of 2012 and March of 2013. They were defined two sampling areas in the districts of Huasicancha and Chicche of the county of Huancayo, Junín. The first of the areas was located in the place Pumahuasi (18L 466456E 8628580N and the second in Vista Alegre (18L 464886E 8642964N, between 3 845 and 3 870 meters of altitude. 10 plants per species were collected at random, between April and May, considering the moment of maximum growth of the plants. The samples were washed and dried off to the atmosphere during 15 days, being completed the drying in a stove to 60 °C, during 48 hours. The determination of the percentage of dry matter of the samples was carried out by the difference between the initial and final weights. While that the determination of the percentage of carbon was carried out through the method of Walkley-Black. The results of the correlation of weight between air biomass and biomass radicular were highly significant r = 0.9856 ** and b = 3.4507. The percentage of the weight of the root regarding that of the air biomass oscillated between 27.93% and 30.20%, respectively. The content of carbon expressed as percentage varied according to the part of the plant and the origin place.

  20. Andean subduction orogeny: feedbacks between tectonics, relief evolution and global climate

    Science.gov (United States)

    Lacassin, Robin; Armijo, Rolando; Coudurier-Curveur, Aurélie; Carrizo, Daniel

    2016-04-01

    The Andean subduction margin, largest tectonic relief on the Earth (13 km vertically from the trench to the Altiplano) has a stepped morphology, which results of the evolution over the past 50 Myr of two parallel flat-ramp thrust systems, at the - previously unidentified - West Andean Thrust (WAT), and at the subduction interface. The evolution of those thrusts appears concomitant with increasing aridity in the Atacama Desert, which keeps a large-scale record of interplaying tectonics and Cenozoic climate change. The coastal morphology is dominated by the Atacama Bench, a giant uplifted terrace at 1-2km asl. Geomorphic and climatic data, numerical experiments of drainage formation are consistent with the development of a flat Atacama morphology close to sea level, interrupted at ≤10 Ma by tectonic uplift prevailing to the present. This suggests recent trench-ward relief growth by incorporation of the coastal Atacama Bench to the Andes reliefs. Thrust splay structures and other complexities above the subduction interface may explain this relief growth, as well as the distribution of asperities under the oceanward forearc, and the down-dip segmentation of coupling and seismicity on the megathrust. Combining those results with geological knowledge at the scale of the whole Central Andes, we show that the Andean orogeny results from protracted processes of bivergent crustal shortening in a wide region squeezed between the rigid Marginal Block and the S America Plate. The overall growth curve of Andean orogeny over the past 50 Myr appears synchronous with the onset of the "ramp-shaped" temperature decrease since the Early Eocene climatic optimum. Andean growth and global cooling may have operated under the same forcing mechanism at plate-scale, involving viscous flow in the mantle. But Andean growth appears modulated by climatic feedbacks causative of stepwise reductions of erosive power over the Andean margin. The first of such events is coeval with Late Eocene

  1. Negative impacts of a vertebrate predator on insect pollinator visitation and seed output in Chuquiraga oppositifolia, a high Andean shrub.

    Science.gov (United States)

    Muñoz, Alejandro A; Arroyo, Mary T K

    2004-01-01

    Studies on plant-pollinator interactions have largely neglected the potential negative effects of the predators of pollinators on seed output, even though anti-predatory behaviour of pollinators may affect visitation patterns, pollen transfer, and therefore potentially, plant reproductive output. We tested the hypothesis that the presence of lizards and insectivorous birds, by reducing pollinator visitation, can have significant negative effects on seed output in the insect-pollinated, genetically self-incompatible lower alpine Andean shrub, Chuquiraga oppositifolia (Asteraceae). The lower alpine belt supports a high density of territorial Liolaemus (Tropiduridae) lizards and low shrubs interspersed among rocks of varying sizes, the latter inhabited by lizards and commonly used by flycatchers Muscisaxicola (Tyrannidae) as perching sites. In a 2x2 factorial predator-exclusion experiment, visitation rates of the most frequent pollinators of C. oppositifolia (the satyrid butterfly Cosmosatyrus chilensis and the syrphid fly Scaeva melanostoma), the duration of pollinator visits, and seed output, were 2-4 times greater when lizards were excluded, while birds had no effect. In a natural experiment, visits by S. melanostoma were 9 times shorter, and pollinator visitation rates of C. chilensis and S. melanostoma, and C. oppositifolia seed output were 2-3 times lower on shrubs growing adjacent to lizard-occupied rocks compared to those growing distant from rocks. Our results, verified for additional Andean sites, suggest that lizard predators can alter the behaviour of pollinators and elicit strong top-down indirect negative effects on seed output. Such effects may be especially important in high alpine plant communities, where pollinator activity can be low and erratic, and pollen limitation has been reported. PMID:14551828

  2. Terrain characterization and structural control of the Auca Mahuida volcanism (Neuquén Basin, Argentina)

    OpenAIRE

    Ventura, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; De Ritis, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Longo, M.; Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, La Plata, Argentina; Chiappini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia

    2013-01-01

    Geomorphometric parameters (slope, aspect, valley depth, and areal density of cones) derived from a moderate resolution digital elevation model with a grid spacing of 100 m are used in an attempt to interpret the tectonic/structural features related to surface deformation in the Auca Mahuida volcanic terrain (Neuquén Basin, Argentina). The Auca Mahuida (2.03–0.88 Ma) is the southernmost volcanic field of the Payenia volcanic province, in the Andean foreland. The foreland is sub...

  3. Longitudinal patterns in fish and macrozoobenthos assemblages reflect degradation of water quality and physical habitat in the Bílina river basin

    Czech Academy of Sciences Publication Activity Database

    Jurajda, Pavel; Adámek, Zdeněk; Janáč, Michal; Valová, Zdenka

    2010-01-01

    Roč. 55, č. 3 (2010), s. 123-136. ISSN 1212-1819 R&D Projects: GA MŠk LC522 Institutional research plan: CEZ:AV0Z60930519 Keywords : fish community * macroinvertebrates * pollution * channelization * Elbe basin Subject RIV: GL - Fishing Impact factor: 1.190, year: 2010 http://www.agriculturejournals.cz/publicFiles/17674.pdf

  4. Ultraviolet-B-driven pigmentation and genetic diversity of benthic macroinvertebrates from high-altitude Andean streams

    NARCIS (Netherlands)

    R.A. Loayza Muro; J.K. Marticorena-Ruíz; E.J. Palomino; C Merrit; J.A.J. Breeuwer; P. Kuperus; M.H.S. Kraak; W. Admiraal

    2013-01-01

    Photoprotective pigments in benthic macroinvertebrates may reduce the damage caused by the blistering UV-B radiation in Andean high-altitude streams above 3500 m. The aim of this study was therefore to determine whether melanisation in macroinvertebrates inhabiting high-altitude Andean streams is an

  5. Mitilanotherium inexpectatum (Giraffidae, Mammalia from Huélago (Lower Pleistocene; Guadix-Baza basin, Granada, Spain - observations on a peculiar biogegraphic pattern

    Directory of Open Access Journals (Sweden)

    Morales, J.

    2011-12-01

    Full Text Available Giraffid fossils from the lowermost Pleistocene (MN17 locality Huélago (Guadix-Baza Basin, Granada, Spain are described and assigned to Mitilanotherium inexpectatum Samson & Radulesco (1966. The remains are compared to giraffid material from the Pliocene and younger. The known geographic distribution of this giraffid is disjunct; it is found in Spain and in an area stretching from Rumania and Greece to Tadzhikistan, but not in central Europe. The oldest record is from the Upper Pliocene (MN16 of Turkey and the youngest is from the Lower Pleistocene of Greece (with an estimated age of about 1.2 Ma. Shortly after 2.6 Ma it may have dispersed to Spain, where it may have lived as much as half a million years. The dispersal did not leave a fossil record in the area between SE Europe and Spain. The same occured with dispersals of other mammals in the Early, Middle and Late Miocene, Pliocene and Pleistocene. These species that show this pattern are interpreted to be adapted to open or arid environments. Their dispersals across Europe to Spain may have occurred during short periods of atypical environmental conditions and thus did not leave an easily detectable fossil record.Los fósiles de jirafas del Pleistoceno basal (MN 17 de la localidad de Huélago (Cuenca de Guadix- Baza, Granada, Spain son descritos y asignados a Mitilanotherium inexpectatum Samson & Radulesco (1966. Los restos fósiles son comparados con jiráfidos del Plioceno, y formas más recientes. La distribución geográfica conocida muestra que es disyunta; encontrándose en España y en un área que se extiende de Rumania y Grecia a Tadzhikistan, pero no en Europa central. El registro más antiguo procede del Plioceno Superior (MN 16 de Turquía y el más reciente del Pleistoceno inferior de Grecia (con una edad estimada de ca. 1, 2 Ma. Poco después de los 2,6 Ma la especie pudo haberse dispersado a España, donde como mucho pudo haber durado medio millón de años. Esta dispersion

  6. The High Andean Cordillera of central Argentina and Chile along the Piuquenes Pass-Cordon del Portillo transect: Darwin's pioneering observations compared with modern geology

    Directory of Open Access Journals (Sweden)

    Laura Giambiagi

    2009-04-01

    Full Text Available The geological observations made by Darwin in 1835 during his crossing of the Andes from Santiago to Mendoza via the Piuquenes Pass and Cordón del Portillo are compared with the present geological knowledge of the Cordillera Principal and Cordillera Frontal at 33°-34°S. The analysis of the complex stratigraphy of the Cordillera Principal, the imbricated structure of the Aconcagua fold and thrust belt, as well as the stratigraphy and structure of the inter mountain foreland Tunuyán Basin, allows to assess the pioneer observations of Darwin. He recognized the old metamorphic basement and the granitoids and volcanic sequences of late Paleozoic to Triassic age of the Cordillera Frontal, established the Cretaceous age of the marine successions cropping out along the eastern Cordillera Principal and studied the conglomeratic deposits associated with the uplift of the Cordillera in the Alto Tunuyán Basin. Based on the study of clast provenance of the synorogenic deposits of the Alto Tunuyán Basin, Darwin recognized that the Cordillera Frontal was uplifted later than the Cordillera Principal. The present knowledge of this sector of the Andean Cordillera confirms his pioneer observations and show that Darwin was one of the first scientists ever in realizing that in an orogenic system the sequence of uplift and deformation proceeds from hinterland towards foreland, according to a process that is exceptionally well-illustrated along the Piuquenes-Cordón del Portillo transect.

  7. Transference of some microsatellite molecular markers from Fabaceae family to Andean Lupin (Lupinus mutabilis Sweet

    Directory of Open Access Journals (Sweden)

    Michelle C. Chirinos-Arias

    2015-03-01

    Full Text Available In order to analyze transferibility of 15 microsatellite primers from Fabaceae family to Lupinus mutabilis Sweet "andean lupine" chosen to present transferability between species and genera, by its high rate of polymorphic content (PIC and high degree of observed and expected heterozygosity. DNA was extracted of 300 andean lupines plants, PCR conditions were standardized by gradients of master mix components. Primers for screening were run on 3% agarose gel with some samples. Finally population was amplified and run on 6% polyacrylamide gel for its highest resolution. Only 6.67% of primers were amplified, but they were monomorphic, so they cannot be used for molecular characterization. We proposed eight microsatellite primers for andean lupin wich should be probed in laboratory conditions.

  8. From foreland rift to forearc basin: Tectono-thermal controls on subsidence and stratigraphic development in the Mesozoic-Recent Salar de Atacama basin, Chilean Andes

    Energy Technology Data Exchange (ETDEWEB)

    Flint, S. (Univ. of Liverpool (United Kingdom)); Turner, P. (Univ. of Birmingham (United Kingdom)); Hartley, A. (Univ. of Wales, Cardiff (United Kingdom)); Jolley, E. (BP Exploration, Glasglow (United Kingdom))

    1991-03-01

    The Salar de Atacama and westerly adjacent Domeyko basins originated as Permian foreland rifts, containing some 2 km of Triassic synrift red beds. Continued extension and volcanic are establishment resulted in deposition of important Jurassic marine source rocks in the Domeyko basin. Rift basin subsidence was controlled by extension, followed by thermal sagging. Middle Cretaceous contraction (opening of the south Atlantic) inverted the Domeyko back-arc basin as a thrustbelt. To the east, the Salar basin subsequently accommodated 4 km of Late Cretaceous-Palaeocene continental detritus. Accommodation space reflected the interplay between limited flexural loading and thermal effects related to a 150 km eastward jump of the Andean volcanic arc to the margin of the arc-related, foreland-style basin. Late Eocene transpression (high rate of oblique convergence between the Farallon and South American plates) inverted the western basin margin, sourcing a 2 km thick Oligocene intra-arc basin-fill component. Accommodation space was controlled by thermal sagging associated with a further 100 km eastward arc jump. The Salar de Atacama basin thus provides a model for the evolution of complex, mixed origin basins associated with a migrating volcanic arc and varying crustal stress regime. The complex interplay between variable tectonic style and thermal processes in controlling subsidence and resultant stratigraphic development is not yet adequately constrained. However, simple, single stage tectono-sedimentary models commonly used in play definition may not be appropriate in complex, arc-related basin settings.

  9. Microsatellite characterization of Andean races of common bean (Phaseolus vulgaris L.).

    Science.gov (United States)

    Blair, M W; Díaz, J M; Hidalgo, R; Díaz, L M; Duque, M C

    2007-12-01

    The Andean gene pool of common bean (Phaseolus vulgaris L.) has high levels of morphological diversity in terms of seed color and size, growth habit and agro-ecological adaptation, but previously was characterized by low levels of molecular marker diversity. Three races have been described within the Andean gene pool: Chile, Nueva Granada and Peru. The objective of this study was to characterize a collection of 123 genotypes representing Andean bean diversity with 33 microsatellite markers that have been useful for characterizing race structure in common beans. The genotypes were from both the primary center of origin as well as secondary centers of diversity to which Andean beans spread and represented all three races of the gene pool. In addition we evaluated a collection of landraces from Colombia to determine if the Nueva Granada and Peru races could be distinguished in genotypes from the northern range of the primary center. Multiple correspondence analyses of the Andean race representatives identified two predominant groups corresponding to the Nueva Granada and Peru races. Some of the Chile race representatives formed a separate group but several that had been defined previously as from this race grouped with the other races. Gene flow was more notable between Nueva Granada and Peru races than between these races and the Chile race. Among the Colombian genotypes, the Nueva Granada and Peru races were identified and introgression between these two races was especially notable. The genetic diversity within the Colombian genotypes was high, reaffirming the importance of this region as an important source of germplasm. Results of this study suggest that the morphological classification of all climbing beans as Peru race genotypes and all bush beans as Nueva Granada race genotypes is erroneous and that growth habit traits have been mixed in both races, requiring a re-adjustment in the concept of morphological races in Andean beans. PMID:17924092

  10. Diverging Responses of Tropical Andean Biomes under Future Climate Conditions

    Science.gov (United States)

    Tovar, Carolina; Arnillas, Carlos Alberto; Cuesta, Francisco; Buytaert, Wouter

    2013-01-01

    Observations and projections for mountain regions show a strong tendency towards upslope displacement of their biomes under future climate conditions. Because of their climatic and topographic heterogeneity, a more complex response is expected for biodiversity hotspots such as tropical mountain regions. This study analyzes potential changes in the distribution of biomes in the Tropical Andes and identifies target areas for conservation. Biome distribution models were developed using logistic regressions. These models were then coupled to an ensemble of 8 global climate models to project future distribution of the Andean biomes and their uncertainties. We analysed projected changes in extent and elevational range and identified regions most prone to change. Our results show a heterogeneous response to climate change. Although the wetter biomes exhibit an upslope displacement of both the upper and the lower boundaries as expected, most dry biomes tend to show downslope expansion. Despite important losses being projected for several biomes, projections suggest that between 74.8% and 83.1% of the current total Tropical Andes will remain stable, depending on the emission scenario and time horizon. Between 3.3% and 7.6% of the study area is projected to change, mostly towards an increase in vertical structure. For the remaining area (13.1%–17.4%), there is no agreement between model projections. These results challenge the common believe that climate change will lead to an upslope displacement of biome boundaries in mountain regions. Instead, our models project diverging responses, including downslope expansion and large areas projected to remain stable. Lastly, a significant part of the area expected to change is already affected by land use changes, which has important implications for management. This, and the inclusion of a comprehensive uncertainty analysis, will help to inform conservation strategies in the Tropical Andes, and to guide similar assessments for

  11. [Structural recovering in Andean successional forests from Porce (Antioquia, Colombia)].

    Science.gov (United States)

    Yepes, Adriana P; del Valle, Jorge I; Jaramillo, Sandra L; Orrego, Sergio A

    2010-03-01

    Places subjected to natural or human disturbance can recover forest through an ecological process called secondary succession. Tropical succession is affected by factors such as disturbances, distance from original forest, surface configuration and local climate. These factors determine the composition of species and the time trend of the succession itself. We studied succession in soils used for cattle ranching over various decades in the Porce Region of Colombia (Andean Colombian forests). A set of twenty five permanent plots was measured, including nine plots (20 x 50 m) in primary forests and sixteen (20 x 25 m) in secondary forests. All trees with diameter > or =1.0 cm were measured. We analyzed stem density, basal area, above-ground biomass and species richness, in a successional process of ca. 43 years, and in primary forests. The secondary forests' age was estimated in previous studies, using radiocarbon dating, aerial photographs and a high-resolution satellite image analysis (7 to >43 years). In total, 1,143 and 1,766 stems were measured in primary and secondary forests, respectively. Basal area (5.7 to 85.4 m2 ha(-1)), above-ground biomass (19.1 to 1,011.5 t ha(-1)) and species richness (4 to 69) directly increased with site age, while steam density decreased (3,180 to 590). Diametric distributions were "J-inverted" for primary forests and even-aged size-class structures for secondary forests. Three species of palms were abundant and exclusive in old secondary forests and primary forests: Oenocarpus mapora, Euterpe precatoria and Oenocarpus bataua. These palms happened in cohorts after forest disturbances. Secondary forest structure was 40% in more than 43 years of forest succession and indicate that many factors are interacting and affecting the forests succession in the area (e.g. agriculture, cattle ranching, mining, etc.). PMID:20411733

  12. Andean grasslands are as productive as tropical cloud forests

    Science.gov (United States)

    Oliveras, I.; Girardin, C.; Doughty, C. E.; Cahuana, N.; Arenas, C. E.; Oliver, V.; Huaraca Huasco, W.; Malhi, Y.

    2014-11-01

    We aim to assess net primary productivity (NPP) and carbon cycling in Andean tropical alpine grasslands (puna) and compare it with NPP of tropical montane cloud forests. We ask the following questions: (1) how do NPP and soil respiration of grasslands vary over the seasonal cycle? (2) how do burning and grazing affect puna productivity? (3) if the montane forest expands into the puna, what will be the resulting change in productivity? The study sites are located at the South-eastern Peruvian Andes; one grassland site and the forest sites are in Wayqecha biological station, and another grassland site in Manu National Park. At each grassland site, we selected a burnt and an unburnt area, installed unfenced and fenced transects in each area, and monitored above-ground productivity (NPPAG), below-ground productivity (NPPBG) and soil respiration (Rs) for 2 yr. In the forest, we monitored NPPAG, NPPBG and Rs for 2-4 yr. Grassland NPP varied between 4.6 ± 0.25 (disturbed areas) to 15.3 ± 0.9 Mg C ha-1 yr-1 (undisturbed areas) and cloud forest NPP was between 7.05 ± 0.39 and 8.0 ± 0.47 Mg C ha-1 yr-1, while soil carbon stocks were in the range of 126 ± 22 to 285 ± 31 Mg C ha-1. There were no significant differences on NPP between the puna and forest sites. The most undisturbed site had significantly higher NPP than other grassland sites, but no differences were found when relating grazing and fire at other sites. There were lower residence times of above-ground biomass compared to below-ground biomass. There was a strong seasonal signal on grassland NPPAG and NPPBG, with a shift on allocation at the beginning of the austral summer. High elevation tropical grasslands can be as productive as adjacent cloud forests, but have very different carbon cycling and retention properties than cloud forests.

  13. Initiation of the Magallanes foreland basin: Timing of the southernmost Patagonian Andes orogeny revised by detrital zircon provenance analysis

    Science.gov (United States)

    Fildani, A.; Cope, T.D.; Graham, S.A.; Wooden, J.L.

    2003-01-01

    New sensitive high-resolution ion microprobe-reverse geometry U-Pb detrital zircon data establish the timing of onset of foreland basin subsidence in the Magallanes basin and the age of the Patagonian Andes in southernmost Chile. Initiation of the Magallanes foreland basin is signaled by the abrupt occurrence of sandstone of the Punta Barrosa Formation, loosely dated as upper Albian-Cenomanian from biofacies assemblages. Detrital zircon analyses demonstrate that the Punta Barrosa Formation is not older than 92 ?? 1 Ma and that the linked Andean belt started forming in the Turonian.

  14. Patrones electroforéticos de proteínas y actividad anticongelante en el apoplasto de la hoja de la especie andina tropical Senecio niveoaureus PROTEIN ELECTROPHORETIC PATTERNS AND ANTIFREEZING ACTIVITY IN THE LEAF APOPLAST OF THE TROPICAL ANDEAN SPECIES Senecio niveoaureus

    Directory of Open Access Journals (Sweden)

    F ÁLVAREZFLÓREZ

    2006-06-01

    Full Text Available Las plantas de alta montaña tienen diferentes adaptaciones para sobrevivir a cambios drásticos de temperatura, especialmente a condiciones de congelamiento. En plantas de invierno, la supervivencia a temperaturas bajas está relacionada con la capacidad de las células para producir proteínas específicas de bajo peso molecular (proteínas anticongelantes y exportarlas al apoplasto. Para establecer si plantas tropicales de alta montaña sobreviven las temperaturas bajas a través del mismo mecanismo, se colectaron hojas de plantas de Senecio niveoaureus durante 24 horas y a dos alturas 3.300 y 3.600 msnm en el Páramo de Palacio, Chingaza, Colombia. Se observaron proteínas apoplásticas de pesos moleculares entre 3512 kDa. Los patrones electroforéticos fueron diferentes dependiendo de la altura y la hora de muestreo, sin embargo, se observaron variaciones en el patrón de bandeo que no pueden ser atribuidas ni a la temperatura ni al gradiente altitudinal únicamente. Se detectó actividad anticongelante en el apoplasto de hojas de S. niveoaureus, siendo este el primer reporte en especies tropicales de alta montaña.Tropical high mountain plants have different adaptations to survive extreme daily temperature fluctuations and specially freezing night conditions. In winter plant species, survival to low temperatures is related to the ability of the cell to produce specific low molecular weight proteins (antifreezing proteins and to export them to the apoplast. In order to see if high mountain tropical plants survive to low temperatures through the same mechanism we collected, during a 24 hourperiod, leaves from Senecio niveoaureus growing at 3,300 and 3,600 m.o.s.l, in the Páramo de Palacio, Chingaza, Colombia. Leaf apoplast proteins had MW between 3512 kDa. Electrophoretic patterns were different depending on the altitude and the time of sampling. However the observed variations could not be linked to changes in temperature or to the

  15. Continental margin deformation along the Andean subduction zone: Thermo-mechanical models

    Science.gov (United States)

    Gerbault, Muriel; Cembrano, J.; Mpodozis, C.; Farias, M.; Pardo, M.

    2009-12-01

    The Chilean Andes extend north-south for about 3000 km over the subducting Nazca plate, and show evidence of local rheological controls on first-order tectonic features. Here, rheological parameters are tested with numerical models of a subduction driven by slab-pull and upper plate velocities, and which calculate the development of stress and strain over a typical period of 4 Myr. The models test the effects of subduction interface strength, arc and fore-arc crust rheology, and arc temperature, on the development of superficial near-surface faulting as well as viscous shear zones in the mantle. Deformation geometries are controlled by the intersection of the subduction interface with continental rheological heterogeneities. Upper plate shortening and trench advance are both correlated, and favored, to a first-order by upper plate weakness, and to a second-order by interface strength. In cases of a strong interface, a weak fore-arc crust is dragged downward by “tectonic erosion”, a scenario for which indications are found along the northern Chilean margin. In contrast for a resistant fore-arc, the slab-pull force transmits to the surface and produces topographic subsidence. This process may explain present-day subsidence of the Salar de Atacama basin and/or the persistence of a Central Depression. Specific conditions for northern Chile produce a shear zone that propagates from the subduction zone in the mantle, through the Altiplano lower crust into the Sub-Andean crust, as proposed by previous studies. Models with a weak interface in turn, allow buoyant subducted material to rise into the continental arc. In case of cessation of the slab-pull, this buoyant material may rise enough to change the stress state in the continental crust, and lead to back-arc opening. In a case of young and hydrated oceanic plate forced by the slab-pull to subduct under a resistant continent, this plate is deviated and indented by the continental mantle, and stretches horizontally

  16. Transport of RFID tracers in a glacierized Andean stream (Estero Morales, Chile)

    Science.gov (United States)

    Rainato, Riccardo; Toro, Matteo; Mao, Luca; Fraccarollo, Luigi; Brardinoni, Francesco; Aristide Lenzi, Mario

    2015-04-01

    A proper quantification of bedload transport is crucial in order to improve the knowledge on the morphology and dynamics of river systems. Unfortunately, bedload surveys in mountain streams are notoriously difficult. Also, equations for predicting the transport capacity often overestimate the actual bedload rates, and field measurement are still rare. An alternative to direct bedload sampling during floods is the use of tracers, which allow to obtain precious data on sediment dynamic and transport due to different conditions of hydraulic forcing, especially in mountain streams. In this work, the results obtained by the employment of passive RFID tracers in a steep Andean channel are presented. The study site is the Estero Morales, a high-gradient stream located in the Metropolitan Region (central Chile). The channel bed exhibits boulder-cascade, step-pool and plane bed morphologies while the average slope is of about 9.5%. The basin (27 km2) hosts the San Francisco glacier (1.8 km2) that strongly affects the hydrological regime. In particular during the melt period (December-March) the glacier ensures daily discharge fluctuations with highly variable associated bedload transport rates. Overall, 429 RFID tracers were installed in the Estero Morales and the displacements over a reach of approximately 700 m were monitored through 15 surveys, performed between January and March 2014. The recovery rate ranges between 19% and 97%. Tracers travel distance were paired to the peaks of stream power per unit area (ω, in W/m2) that occurred during the study period. Due to the wide range of flow magnitude observed, the values of stream power were grouped in three classes: low (650-750 W/m2), moderate (750-800 W/m2), and high (800-900 W/m2). Despite the different conditions of hydraulic forcing, moderate and low classes show mean displacement very similar, equal to 33 m and 24 m, respectively. In either cases a size selective transport was observed. On the other hand, the high

  17. Three perceptions of the evapotranspiration landscape: comparing spatial patterns from a distributed hydrological model, remotely sensed surface temperatures, and sub-basin water balances

    OpenAIRE

    Conradt, T.; Wechsung, F.; Bronstert, A.

    2013-01-01

    A problem encountered by many distributed hydrological modelling studies is high simulation errors at interior gauges when the model is only globally calibrated at the outlet. We simulated river runoff in the Elbe River basin in central Europe (148 268 km2) with the semi-distributed eco-hydrological model SWIM (Soil and Water Integrated Model). While global parameter optimisation led to Nash–Sutcliffe efficiencies of 0.9 at the main outlet gauge, comparisons with measured runoff series ...

  18. Three perceptions of the evapotranspiration landscape: comparing spatial patterns from a distributed hydrological model, remotely sensed surface temperatures, and sub-basin water balances

    OpenAIRE

    Conradt, T.; Wechsung, F.; Bronstert, A.

    2013-01-01

    A problem encountered by many distributed hydrological modelling studies is high simulation errors at interior gauges when the model is only globally calibrated at the outlet. We simulated river runoff in the Elbe River basin in Central Europe (148 268 km2) with the semi-distributed eco-hydrological model SWIM. While global parameter optimisation led to Nash–Sutcliffe efficiencies of 0.9 at the main outlet gauge, comparisons with measured runoff series at interio...

  19. Three perceptions of the evapotranspiration landscape: comparing spatial patterns from a distributed hydrological model, remotely sensed surface temperatures, and sub-basin water balances

    OpenAIRE

    T. Conradt; F. Wechsung; A. Bronstert

    2013-01-01

    A problem encountered by many distributed hydrological modelling studies is high simulation errors at interior gauges when the model is only globally calibrated at the outlet. We simulated river runoff in the Elbe River basin in central Europe (148 268 km2) with the semi-distributed eco-hydrological model SWIM (Soil and Water Integrated Model). While global parameter optimisation led to Nash–Sutcliffe efficiencies of 0.9 at the main outlet...

  20. Cross-cutting Ties and Coexistence: Intermarriage, Land Rentals and Changing Land Use Patterns among Maasai and Kikuyu of Maiella and Enoosupukia, Lake Naivasha Basin, Kenya

    OpenAIRE

    Kioko, Eric Mutisya; Bollig, Michael

    2015-01-01

    This paper explores the value of cross-cutting ties and conflicting loyalties for the peaceful management of conflicts and the emergence of collective action across previously violently contested community boundaries in two communities in the Lake Naivasha Basin, Kenya. In the researched communities cross-cutting ties result from intermarriages, land rentals and friendship. Fieldwork was conducted in six neighbouring villages on the border between Nakuru and Narok Counties in 2013 and early 2...

  1. Investigating the causality of changes in the landscape pattern of Lake Urmia basin, Iran using remote sensing and time series analysis.

    Science.gov (United States)

    Mehrian, Majid Ramezani; Hernandez, Raul Ponce; Yavari, Ahmad Reza; Faryadi, Shahrzad; Salehi, Esmaeil

    2016-08-01

    Lake Urmia is the second largest hypersaline lake in the world in terms of surface area. In recent decades, the drop in water level of the lake has been one of the most important environmental issues in Iran. At present, the entire basin is threatened due to abrupt decline of the lake's water level and the consequent increase in salinity. Despite the numerous studies, there is still an ambiguity about the main cause of this environmental crisis. This paper is an attempt to detect the changes in the landscape structure of the main elements of the whole basin using remote sensing techniques and analyze the results against climate data with time series analysis for the purpose of achieving a more clarified illustration of processes and trends. Trend analysis of the different affecting factors indicates that the main cause of the drastic dry out of the lake is the huge expansion of irrigated agriculture in the basin between 1999 and 2014. The climatological parameters including precipitation and temperature cannot be the main reasons for reduced water level in the lake. The results show how the increase in irrigated agricultural area without considering the water resources limits can lead to a regional disaster. The approach used in this study can be a useful tool to monitor and assess the causality of environmental disaster. PMID:27406207

  2. Patterns of species richness and composition of fish assemblages in streams of the Ivinhema River basin, Upper Paraná River Padrões de riqueza e composição de espécies das assembleias de peixes em riachos da bacia do rio Ivinhema, Alto Rio Paraná

    OpenAIRE

    Yzel Rondon Súarez; Marcelo Maldonado de Souza; Fabiane Silva Ferreira; Maiane Jardim Pereira; Ediléia Amancio da Silva; Lidiani Queli Lubas Ximenes; Luciana Gonçalves de Azevedo; Olemar Cáceres Martins; Sidnei Eduardo Lima Júnior

    2011-01-01

    AIM: The present study analyzed the spatial variation in fish species richness and composition in streams of the Ivinhema River basin, Upper Paraná basin, determining the relationship between local and regional descriptors of the fish assemblage organization; METHOD: From 2001 to 2011 we sampled 200 stream stretches, using different sampling methods. Local species richness and composition were analyzed using univariate and multivariate methods to detect patterns of variation in the fish assem...

  3. The Under-side of the Andes: Using Receiver Functions to Map the North Central Andean Subsurface

    Science.gov (United States)

    Ryan, J. C.; Beck, S. L.; Zandt, G.; Wagner, L. S.; Minaya, E.; Tavera, H.

    2012-12-01

    The Central Andean Uplift and Geodynamics of High Topography (CAUGHT) project is an interdisciplinary project to investigate connections between lithospheric removal, crustal shortening and surface uplift in the northern Bolivia and southern Peru region of the South American Andean orogen. The central Andes are defined by six major tectonomorphic provinces; the forearc, the volcanically active Western Cordillera (WC, ~6 km elevation), the internally drained Altiplano (~4 km elevation), an inactive fold and thrust belt in the Eastern Cordillera (EC, ~6 km elevation), a lower elevation active fold and thrust belt in the Subandean (SA) zone and the Beni, a foreland basin. Forty seismic stations installed for the CAUGHT project were deployed between 13° and 18° S latitude, covering the transition zone where the Altiplano region pinches out in southern Peru, in an effort to better constrain the changing character of the crust and mantle lithosphere. Geologic studies across the northern Bolivian portion of the eastern Andean margin (15-17° S) have documented a total of 275 km of upper crustal shortening (McQuarrie et al, Tectonics, v27, 2008), which may be associated with crustal thickening and/or the removal of lithospheric material as a thickened lithosphere root becomes unstable. For this receiver function (converted wave) study, we have little coverage in the forearc and foreland, ~75 km spacing in most of the array, and a relatively dense ~20 km spaced profile along the Charaña-La Paz-Yucumo transect, the eastern portion of which is nearly coincident with the balanced cross-section of McQuarrie et al. (2008). Using the first year of available data, more than 1200 receiver functions have been calculated using an iterative deconvolution method, and stacked using the common conversion point (CCP) method, along profiles parallel to and nearly coincident to those used for the geologic shortening estimates. We identified arrivals for the Moho and generated a 3D map of

  4. Adaptation of a pattern-scaling approach for assessment of local (village/valley) scale water resources and related vulnerabilities in the Upper Indus Basin

    Science.gov (United States)

    Forsythe, Nathan; Kilsby, Chris G.; Fowler, Hayley J.; Archer, David R.

    2010-05-01

    The water resources of the Upper Indus Basin (UIB) are of the utmost importance to the economic wellbeing of Pakistan. The irrigated agriculture made possible by Indus river runoff underpins the food security for Pakistan's nearly 200 million people. Contributions from hydropower account for more than one fifth of peak installed electrical generating capacity in a country where widespread, prolonged load-shedding handicaps business activity and industrial development. Pakistan's further socio-economic development thus depends largely on optimisation of its precious water resources. Confident, accurate seasonal predictions of water resource availability coupled with sound understanding of interannual variability are urgent insights needed by development planners and infrastructure managers at all levels. This study focuses on the challenge of providing meaningful quantitative information at the village/valley scale in the upper reaches of the UIB. Proceeding by progressive reductions in scale, the typology of the observed UIB hydrological regimes -- glacial, nival and pluvial -- are examined with special emphasis on interannual variability for individual seasons. Variations in discharge (runoff) are compared to observations of climate parameters (temperature, precipitation) and available spatial data (elevation, snow cover and snow-water-equivalent). The first scale presented is composed of the large-scale, long-record gauged UIB tributary basins. The Pakistan Water and Power Development Authority (WAPDA) has maintained these stations for several decades in order to monitor seasonal flows and accumulate data for design of further infrastructure. Data from basins defined by five gauging stations on the Indus, Hunza, Gilgit and Astore rivers are examined. The second scale presented is a set of smaller gauged headwater catchments with short records. These gauges were installed by WAPDA and its partners amongst the international development agencies to assess potential

  5. Characterization of Two Microbial Isolates from Andean Lakes in Bolivia

    Science.gov (United States)

    Demergasso, C.; Blamey, J.; Escudero, L.; Chong, G.; Casamayor, E. O.; Cabrol, N. A.; Grin, E. A.; Hock, A.; Kiss, A.; Borics, G.

    2004-01-01

    We are currently investigating the biological population present in the highest and least explored perennial lakes on earth in the Bolivian and Chilean Andes, including several volcanic crater lakes of more than 6000 m elevation, in combination of microbiological and molecular biological methods. Our samples were collected in saline lakes of the Laguna Blanca Laguna Verde area in the Bolivian Altiplano and in the Licancabur volcano crater (27 deg. 47 min S/67 deg. 47 min. W) in the ongoing project studying high altitude lakes. The main goal of the project is to look for analogies with Martian paleolakes. These Bolivian lakes can be described as Andean lakes following the classification of Chong. We have attempted to isolate pure cultures and phylogenetically characterize prokaryotes that grew under laboratory conditions. Sediment samples taken from the Licancabur crater lake (LC), Laguna Verde (LV), and Laguna Blanca (LB) were analyzed and cultured using enriched liquid media under both aerobic and anaerobic conditions. All cultures were incubated at room temperature (15 to 20 C) and under light exposure. For the reported isolates, 36 hours incubation were necessary for reaching optimal optical densities to consider them viable cultures. Ten serial dilutions starting from 1% inoculum were required to obtain a suitable enriched cell culture to transfer into solid media. Cultures on solid medium were necessary to verify the formation of colonies in order to isolate pure cultures. Different solid media were prepared using several combinations of both trace minerals and carbohydrates sources in order to fit their nutrient requirements. The microorganisms formed individual colonies on solid media enriched with tryptone, yeast extract and sodium chloride. Cells morphology was studied by optical and electronic microscopy. Rodshape morphologies were observed in most cases. Total bacterial genomic DNA was isolated from 50 ml late-exponential phase culture by using the CTAB

  6. Andean grasslands are as productive as tropical cloud forests

    International Nuclear Information System (INIS)

    We aim to assess net primary productivity (NPP) and carbon cycling in Andean tropical alpine grasslands (puna) and compare it with NPP of tropical montane cloud forests. We ask the following questions: (1) how do NPP and soil respiration of grasslands vary over the seasonal cycle? (2) how do burning and grazing affect puna productivity? (3) if the montane forest expands into the puna, what will be the resulting change in productivity? The study sites are located at the South-eastern Peruvian Andes; one grassland site and the forest sites are in Wayqecha biological station, and another grassland site in Manu National Park. At each grassland site, we selected a burnt and an unburnt area, installed unfenced and fenced transects in each area, and monitored above-ground productivity (NPPAG), below-ground productivity (NPPBG) and soil respiration (Rs) for 2 yr. In the forest, we monitored NPPAG, NPPBG and Rs for 2–4 yr. Grassland NPP varied between 4.6 ± 0.25 (disturbed areas) to 15.3 ± 0.9 Mg C ha−1 yr−1 (undisturbed areas) and cloud forest NPP was between 7.05 ± 0.39 and 8.0 ± 0.47 Mg C ha−1 yr−1, while soil carbon stocks were in the range of 126 ± 22 to 285 ± 31 Mg C ha−1. There were no significant differences on NPP between the puna and forest sites. The most undisturbed site had significantly higher NPP than other grassland sites, but no differences were found when relating grazing and fire at other sites. There were lower residence times of above-ground biomass compared to below-ground biomass. There was a strong seasonal signal on grassland NPPAG and NPPBG, with a shift on allocation at the beginning of the austral summer. High elevation tropical grasslands can be as productive as adjacent cloud forests, but have very different carbon cycling and retention properties than cloud forests. (paper)

  7. Genetic admixture and lineage separation in a southern Andean plant

    Science.gov (United States)

    Morello, Santiago; Sede, Silvana M.

    2016-01-01

    Mountain uplifts have generated new ecologic opportunities for plants, and triggered evolutionary processes, favouring an increase on the speciation rate in all continents. Moreover, mountain ranges may act as corridors or barriers for plant lineages and populations. In South America a high rate of diversification has been linked to Andean orogeny during Pliocene/Miocene. More recently, Pleistocene glacial cycles have also shaped species distribution and demography. The endemic genus Escallonia is known to have diversified in the Andes. Species with similar morphology obscure species delimitation and plants with intermediate characters occur naturally. The aim of this study is to characterize genetic variation and structure of two widespread species of Escallonia: E. alpina and E. rubra. We analyzed the genetic variation of populations of the entire distribution range of the species and we also included those with intermediate morphological characters; a total of 94 accessions from 14 populations were used for the Amplified Fragment Length Polymorphism (AFLP) analysis. Plastid DNA sequences (trnS-trnG, 3′trnV-ndhC intergenic spacers and the ndhF gene) from sixteen accessions of Escallonia species were used to construct a Statistical Parsimony network. Additionally, we performed a geometric morphometrics analysis on 88 leaves from 35 individuals of the two E. alpina varieties to further study their differences. Wright’s Fst and analysis of molecular variance tests performed on AFLP data showed a significant level of genetic structure at the species and population levels. Intermediate morphology populations showed a mixed genetic contribution from E. alpina var. alpina and E. rubra both in the Principal Coordinates Analysis (PCoA) and STRUCTURE. On the other hand, E. rubra and the two varieties of E. alpina are well differentiated and assigned to different genetic clusters. Moreover, the Statistical Parsimony network showed a high degree of divergence between the

  8. The implications of geology, soils, and vegetation on landscape morphology: Inferences from semi-arid basins with complex vegetation patterns in Central New Mexico, USA

    Science.gov (United States)

    Yetemen, Omer; Istanbulluoglu, Erkan; Vivoni, Enrique R.

    2010-04-01

    This paper examines the relationship between land surface properties (e.g. soil, vegetation, and lithology) and landscape morphology quantified by the catchment descriptors: the slope-area (S-A) relation, curvature-area (C-A) relation, and the cumulative area distribution (CAD), in two semi-arid basins in central New Mexico. The first site is composed of several basins located in today's desert elevations with mesic north-facing and xeric south-facing hillslopes underlain by different lithological formations. The second site is a mountainous basin exhibiting vegetation gradients from shrublands in the lower elevations to grasslands and forests at higher elevations. All three land surface properties were found to have significant influences on the S-A and C- A relations, while the power-law exponents of the CADs for these properties did not show any significant deviations from the narrow range of universal scaling exponents reported in the literature. Among the three different surface properties we investigated, vegetation had the most profound impact on the catchment descriptors. In the S-A diagrams of the aspect-controlled ecosystems, we found steeper slopes in north-facing aspects than south-facing aspects for a given drainage area. In elevation-controlled ecosystems, forested landscapes exhibited the steepest slopes for the range of drainage areas examined, followed by shrublands and grasslands in all soil textures and lithologies. In the C-A diagrams, steeper slopes led to a higher degree of divergence on hillslopes and a higher degree of convergence in the valleys than shallower slopes. The influence of functional types of vegetation detected on observed topography provided some initial understanding of the potential impacts of life on the organization of topography. This finding also emphasizes the critical role of climate in catchment development. We suggest that climatic fluctuations that are capable of replacing vegetation communities could lead to highly

  9. Forests of the tropical eastern Andean flank during the middle Pleistocene

    NARCIS (Netherlands)

    M.L. Cárdenas; W.D. Gosling; R.T. Pennington; I. Poole; S.C. Sherlock; P. Mothes

    2014-01-01

    Inter-bedded volcanic and organic sediments from Erazo (Ecuador) indicate the presence of four different forest assemblages on the eastern Andean flank during the middle Pleistocene. Radiometric dates (40Ar-39Ar) obtained from the volcanic ash indicate that deposition occurred between 620,000 and 19

  10. Marcos Zapata's "Last Supper": a feast of European religion and Andean culture.

    Science.gov (United States)

    Zendt, Christina

    2010-01-01

    In Marcos Zapata's 1753 painting of the Last Supper in Cuzco, Peru, Christian symbolism is filtered through Andean cultural tradition. Zapata was a late member of the Cuzco School of Painting, a group comprised of few European immigrants and handfuls of mestizo and Indian artists. The painters in Cuzco learned mostly from prints of European paintings, and their style tends to blend local culture into the traditional painting of their conquistadors. Imagery was the most successful tool used by the Spaniards in their quest to Christianize the Andean population. By teaching locals to paint Christian subjects, they were able to infuse Christianity into Andean traditions. Zapata's rendering of the Last Supper utilizes this cultural blending while staying true to the Christian symbolism within the subject. Instead of the traditional lamb, Zapata's Last Supper features a platter of cuy, or guinea pig, an Andean delicacy stocked with protein as well as cultural significance. Cuy was traditionally a sacrificial animal at Inca agricultural festivals and in this way it offers poignant parallel to the lamb, as a traditional Christian sacrificial animal. PMID:21568039

  11. The abiotic and biotic drivers of rapid diversification in Andean bellflowers (Campanulaceae).

    Science.gov (United States)

    Lagomarsino, Laura P; Condamine, Fabien L; Antonelli, Alexandre; Mulch, Andreas; Davis, Charles C

    2016-06-01

    The tropical Andes of South America, the world's richest biodiversity hotspot, are home to many rapid radiations. While geological, climatic, and ecological processes collectively explain such radiations, their relative contributions are seldom examined within a single clade. We explore the contribution of these factors by applying a series of diversification models that incorporate mountain building, climate change, and trait evolution to the first dated phylogeny of Andean bellflowers (Campanulaceae: Lobelioideae). Our framework is novel for its direct incorporation of geological data on Andean uplift into a macroevolutionary model. We show that speciation and extinction are differentially influenced by abiotic factors: speciation rates rose concurrently with Andean elevation, while extinction rates decreased during global cooling. Pollination syndrome and fruit type, both biotic traits known to facilitate mutualisms, played an additional role in driving diversification. These abiotic and biotic factors resulted in one of the fastest radiations reported to date: the centropogonids, whose 550 species arose in the last 5 million yr. Our study represents a significant advance in our understanding of plant evolution in Andean cloud forests. It further highlights the power of combining phylogenetic and Earth science models to explore the interplay of geology, climate, and ecology in generating the world's biodiversity. PMID:26990796

  12. A novel cold active esterase derived from Colombian high Andean forest soil metagenome

    NARCIS (Netherlands)

    Jiménez, Diego Javier; Montaña, José Salvador; Alvarez, Diana; Baena, Sandra

    2012-01-01

    In order to search new lipolytic enzymes and conduct bioprospecting of microbial communities from high Andean forest soil, a metagenomic library of approximately 20,000 clones was constructed in Escherichia coli using plasmid p-Bluescript II SK+. The library covered 80 Mb of the metagenomic DNA main

  13. Taxonomic and functional assignment of cloned sequences from high Andean forest soil metagenome

    NARCIS (Netherlands)

    Montaña, José Salvador; Jiménez Avella, Diego; Angel, Tatiana; Hernández, Mónica; Baena, Sandra

    2012-01-01

    Total metagenomic DNA was isolated from high Andean forest soil and subjected to taxonomical and functional composition analyses by means of clone library generation and sequencing. The obtained yield of 1.7 μg of DNA/g of soil was used to construct a metagenomic library of approximately 20,000 clon

  14. The electronic procurement in the framework of the Andean Community. State of the art

    OpenAIRE

    William David Hernández Martínez

    2010-01-01

    The article is structured as a brief survey of the academic and policy approach on the unification or harmonization of regulations about electronic commerce, specifically relating the electronic contracts, in Latin America, with special emphasis on the Andean Community of Nations as a proposed work on the development of modern trends of international trade law.

  15. Synopsis of Central Andean Orthalicoid land snails (Gastropoda, Stylommatophora), excluding Bulimulidae

    OpenAIRE

    Abraham S.H. Breure; Avila, Valentín Mogollón

    2016-01-01

    Abstract A faunal overview is presented of the molluscan families Amphibulimidae , Megaspiridae , Odontostomidae , Orthalicidae , Simpulopsidae in Bolivia, Ecuador, and Peru. These Central Andean countries are known for their biodiverse malacofauna, of which the superfamily Orthalicoidea takes relatively a large share. In this paper the five families containing 103 (sub)species, for which systematic information (original publication, type locality, type depository, summarizing literature) and...

  16. Persistence of chironomids in metal polluted Andean high altitude streams: does melanin play a role?

    NARCIS (Netherlands)

    R.A. Loayza Muro; J.K. Marticorena-Ruíz; E.J. Palomino; C. Merritt; M.L. de Baat; M. van Gemert; R.A. Verweij; M.H.S. Kraak; W. Admiraal

    2013-01-01

    In high altitude Andean streams an intense solar radiation and coinciding metal pollution allow the persistence of only a few specialized taxa, including chironomids. The aim of the present study was therefore to determine the mechanisms underlying the persistence of chironomids under these multiple

  17. Phylogeny and historical biogeography of trans-Andean cichlid fishes (Teleostei: Cichlidae)

    Czech Academy of Sciences Publication Activity Database

    Musilová, Zuzana; Říčan, O.; Říčanová, Š.; Janšta, P.; Gahura, O.; Novák, J.

    2015-01-01

    Roč. 65, č. 3 (2015), s. 333-350. ISSN 1864-5755 R&D Projects: GA MŠk LC06073 Institutional support: RVO:67985904 Keywords : Andean uplift * Andinoacara * Mesoheros Subject RIV: EG - Zoology Impact factor: 0.593, year: 2014

  18. 76 FR 8766 - Agency Information Collection Activities: Andean Trade Preference Act

    Science.gov (United States)

    2011-02-15

    ... Register (75 FR 73118) on November 29, 2010, allowing for a 60-day comment period. This notice allows for... Preference Act AGENCY: U.S. Customs and Border Protection, Department of Homeland Security. ACTION: 30-Day... accordance with the Paperwork Reduction Act: Andean Trade Preference Act. This is a proposed extension of...

  19. The hydrological regime of a forested tropical Andean catchment

    OpenAIRE

    Clark, K. E.; Torres, M. A.; West, A.J.; R. G. Hilton; New, M; Horwath, A. B.; J. B. Fisher; Rapp, J. M.; A. Robles Caceres; Y. Malhi

    2014-01-01

    The hydrology of tropical mountain catchments plays a central role in ecological function, geochemical and biogeochemical cycles, erosion and sediment production, and water supply in globally important environments. There have been few studies quantifying the seasonal and annual water budgets in the montane tropics, particularly in cloud forests. We investigated the water balance and hydrologic regime of the Kosñipata catchment (basin area: 164.4 km2) over the period 2010–20...

  20. Application of SEBAL approach and MODIS time-series to map vegetation water use patterns in the data scarce Krishna river basin of India.

    Science.gov (United States)

    Ahmad, M D; Biggs, T; Turral, H; Scott, C A

    2006-01-01

    Evapotranspiration (ET) from irrigated land is one of the most useful indicators to explain whether the water is used as "intended". In this study, the Surface Energy Balance Algorithm for Land (SEBAL) was used to compute actual ET from a Landsat7 image of December 29, 2000 for diverse land use in the Krishna Basin in India. SEBAL ETa varies between 0 to 4.7 mm per day over the image and was quantified for identified land use classes. Seasonal/annual comparison of ETa from different land uses requires time series images, processed by SEBAL. In this study, the Landsat-derived snapshot SEBAL ETa result was interpreted using the cropping calendar and time series analysis of MODIS imagery. The wastewater irrigated area in the basin has the highest ETa in the image, partly due to its advanced growth stage compared to groundwater-irrigated rice. Shrub and forests in the senescence phase have similar ETa to vegetable/cash crops, and ETa from grasslands is a low 0.8 mm per day after the end of the monsoon. The results indicate that wastewater irrigation of fodder and rice is sufficient to meet crop water demand but there appears to be deficit irrigation of rice using groundwater. PMID:16838692

  1. Patterns and drivers of riverine particulate organic carbon transport in an Andean valley

    OpenAIRE

    Clark, Kathryn Elizabeth; Malhi, Yadvinder; New, Mark

    2014-01-01

    Physical erosion can mobilise particulate organic carbon (POC) from vegetation and soil, representing an export of primary productivity from ecosystems, and a lateral transfer of carbon recently-derived from the atmosphere. These carbon transfers are thought to be enhanced in mountain forests where erosion rates are high. However, the rates and controls on POC transfer remain poorly constrained, as does the impact of POC export on carbon cycling at regional and global scales. This thesis take...

  2. Shifts in leaf litter breakdown along a forest-pasture-urban gradient in Andean streams.

    Science.gov (United States)

    Iñiguez-Armijos, Carlos; Rausche, Sirkka; Cueva, Augusta; Sánchez-Rodríguez, Aminael; Espinosa, Carlos; Breuer, Lutz

    2016-07-01

    Tropical montane ecosystems of the Andes are critically threatened by a rapid land-use change which can potentially affect stream variables, aquatic communities, and ecosystem processes such as leaf litter breakdown. However, these effects have not been sufficiently investigated in the Andean region and at high altitude locations in general. Here, we studied the influence of land use (forest-pasture-urban) on stream physico-chemical variables (e.g., water temperature, nutrient concentration, and pH), aquatic communities (macroinvertebrates and aquatic fungi) and leaf litter breakdown rates in Andean streams (southern Ecuador), and how variation in those stream physico-chemical variables affect macroinvertebrates and fungi related to leaf litter breakdown. We found that pH, water temperature, and nutrient concentration increased along the land-use gradient. Macroinvertebrate communities were significantly different between land uses. Shredder richness and abundance were lower in pasture than forest sites and totally absent in urban sites, and fungal richness and biomass were higher in forest sites than in pasture and urban sites. Leaf litter breakdown rates became slower as riparian land use changed from natural to anthropogenically disturbed conditions and were largely determined by pH, water temperature, phosphate concentration, fungal activity, and single species of leaf-shredding invertebrates. Our findings provide evidence that leaf litter breakdown in Andean streams is sensitive to riparian land-use change, with urban streams being the most affected. In addition, this study highlights the role of fungal biomass and shredder species (Phylloicus; Trichoptera and Anchytarsus; Coleoptera) on leaf litter breakdown in Andean streams and the contribution of aquatic fungi in supporting this ecosystem process when shredders are absent or present low abundance in streams affected by urbanization. Finally, we summarize important implications in terms of managing of

  3. Andean Condor (Vultur gryphus) in Ecuador: Geographic Distribution, Population Size and Extinction Risk.

    Science.gov (United States)

    Naveda-Rodríguez, Adrián; Vargas, Félix Hernán; Kohn, Sebastián; Zapata-Ríos, Galo

    2016-01-01

    The Andean Condor (Vultur gryphus) in Ecuador is classified as Critically Endangered. Before 2015, standardized and systematic estimates of geographic distribution, population size and structure were not available for this species, hampering the assessment of its current status and hindering the design and implementation of effective conservation actions. In this study, we performed the first quantitative assessment of geographic distribution, population size and population viability of Andean Condor in Ecuador. We used a methodological approach that included an ecological niche model to study geographic distribution, a simultaneous survey of 70 roosting sites to estimate population size and a population viability analysis (PVA) for the next 100 years. Geographic distribution in the form of extent of occurrence was 49 725 km2. During a two-day census, 93 Andean Condors were recorded and a population of 94 to 102 individuals was estimated. In this population, adult-to-immature ratio was 1:0.5. In the modeled PVA scenarios, the probability of extinction, mean time to extinction and minimum population size varied from zero to 100%, 63 years and 193 individuals, respectively. Habitat loss is the greatest threat to the conservation of Andean Condor populations in Ecuador. Population size reduction in scenarios that included habitat loss began within the first 15 years of this threat. Population reinforcement had no effects on the recovery of Andean Condor populations given the current status of the species in Ecuador. The population size estimate presented in this study is the lower than those reported previously in other countries where the species occur. The inferences derived from the population viability analysis have implications for Condor management in Ecuador. This study highlights the need to redirect efforts from captive breeding and population reinforcement to habitat conservation. PMID:26986004

  4. Reconciling Local and Global Agendas in Sustainable Development: Participatory Research with Indigenous Andean Communities

    Institute of Scientific and Technical Information of China (English)

    Robert E. Rhoades; Virginia Nazarea

    2006-01-01

    This paper discusses participatory research in the Andes and presents a case study in Cotacachi, Ecuador, where sustainability scientists and indigenous people seek common ground in their respective but drastically different research and social agendas. Participatory research based on Andean experiences pre-dated and inspired much of the later international movement in agriculture, health, and conservation. Andean communities have a long history in demanding that outsiders address the needs of the community as a condition for carrying out scientific or applied activities. What an Andean community, however, sees as relevant may or may not practiced throughout much of the world. In fact,overzealous participatory researchers are just as bothersome as their predecessors bearing long questionnaires. More important to Andean people is an equitable relationship with researchers and developers in which exchanges of value are made. A research is drawn. In the case of the SANREM project in Cotacachi, Ecuador, scientists carried out enriching research activities of interest to local people as a way to generate social capital for conducting basic research which does not have an obvious, immediate local benefit. The requested research did not have a conventional participatory methodology but provided valuable products (educational opportunity,germplasm, community visualization tools, and information) to the indigenous community in exchange for time and resources to conduct research on more basic natural resource questions. We argue that in the Andean context the key to reconciling the needs of scientists and of local needs is seeking new forms of equitable collaboration which reach beyond the present and now somewhat tired discourse of ‘participation'.

  5. Pertinent spatio-temporal scale of observation to understand sediment yield control factors in the Andean Region: the case of the Santa River (Peru

    Directory of Open Access Journals (Sweden)

    S. B. Morera

    2013-01-01

    Full Text Available Hydro-sedimentology development is a great challenge in Peru due to limited data as well as sparse and confidential information. Consequently, little is known at present about the relationship between the El Niño Southern Oscillation (ENSO, precipitation, runoff, land use and the sediment transport dynamics. The aim of this paper is to bridge this gap in order to quantify and understand the signal of magnitude and frequency of the sediment fluxes from the central western Andes; also, to identify the main erosion control factor and its relevance.

    The Tablachaca River (3132 km2 and the Santa River (6815 km2, two mountainous Andean catchments that are geographically close to each other, both showed similar statistical daily rainfall and discharge variability but high contrast in sediment yield (SY. In order to investigate which factors are of importance, the continuous water discharge and hourly suspended sediment concentrations (SSC of the Santa River were studied. Firstly, the specific sediment yield (SSY at the continental Andes range scale for the Pacific side is one of the highest amounts (2204 t km2 yr−1. Secondly, no relationship between the water discharge (Q and El Niño/La Niñ a events is found over a 54 yr time period. However, the Santa Basin is highly sensitive during mega Niños (1982–1983 and 1997–1998. Lastly, dispersed micro-mining and mining activity in specific lithologies are identified as the major factors that control the high SSY. These remarks make the Peruvian coast key areas for future research on Andean sediment rates.

  6. Geometry and kinematics of the Andean thick-skinned thrust systems: Insights from the Chilean Frontal Cordillera (28°-28.5°S), Central Andes

    Science.gov (United States)

    Martínez, F.; Arriagada, C.; Valdivia, R.; Deckart, K.; Peña, M.

    2015-12-01

    The structure of the Chilean Frontal Cordillera, located over the Central Andes flat-slab subduction segment (27°-28.5°S), is characterized by a thick-skinned deformation, affecting both the pre-rift basement and the Mesozoic and Cenozoic infill of the NNE-SSW Lautaro and Lagunillas Basins, which were developed during the Pangea-Gondwana break-up. The compressive deformation show a complex interaction between Mesozoic rift structures and thrust systems, affecting a suite of Permo-Triassic (258-245 Ma) granitic blocks. We used a combination of geological mapping, new structural data, balanced and restored cross sections and geochronological data to investigate the geometry and kinematics of the Andean thick-skinned thrust systems of the region. The thrust systems include double-vergent thick-skinned thrust faults, basement-cored anticlines and minor thin-skinned thrusts and folds. The presence of Triassic and Jurassic syn-rift successions along the hanging wall and footwall of the basement thrust faults are keys to suggest that the current structural framework of the region should be associated with the shortening of previous Mesozoic half grabens. Based on this interpretation, we propose a deformation mechanism characterized by the tectonic inversion of rift-related faults and the propagation of basement ramps that fold and cut both, the early normal faults and the basement highs. New U-Pb ages obtained from synorogenic deposits (Quebrada Seca and Doña Ana formations) indicate at least three important compressive pulses. A first pulse at ˜80 Ma (Late Cretaceous), a second pulse related to the K-T phase of Andean deformation and, finally, a third pulse that occurred during the lower Miocene.

  7. Pertinent spatio-temporal scale of observation to understand sediment yield control factors in the Andean Region: the case of the Santa River (Peru)

    Science.gov (United States)

    Morera, S. B.; Condom, T.; Vauchel, P.; Guyot, J.-L.; Galvez, C.; Crave, A.

    2013-01-01

    Hydro-sedimentology development is a great challenge in Peru due to limited data as well as sparse and confidential information. Consequently, little is known at present about the relationship between the El Niño Southern Oscillation (ENSO), precipitation, runoff, land use and the sediment transport dynamics. The aim of this paper is to bridge this gap in order to quantify and understand the signal of magnitude and frequency of the sediment fluxes from the central western Andes; also, to identify the main erosion control factor and its relevance. The Tablachaca River (3132 km2) and the Santa River (6815 km2), two mountainous Andean catchments that are geographically close to each other, both showed similar statistical daily rainfall and discharge variability but high contrast in sediment yield (SY). In order to investigate which factors are of importance, the continuous water discharge and hourly suspended sediment concentrations (SSC) of the Santa River were studied. Firstly, the specific sediment yield (SSY) at the continental Andes range scale for the Pacific side is one of the highest amounts (2204 t km2 yr-1). Secondly, no relationship between the water discharge (Q) and El Niño/La Niñ a events is found over a 54 yr time period. However, the Santa Basin is highly sensitive during mega Niños (1982-1983 and 1997-1998). Lastly, dispersed micro-mining and mining activity in specific lithologies are identified as the major factors that control the high SSY. These remarks make the Peruvian coast key areas for future research on Andean sediment rates.

  8. Cryptospores and miospores, their distribution patterns in the Lower Old Red Sandstone of the Anglo-Welsh Basin, and the habitat of their parent plants

    Directory of Open Access Journals (Sweden)

    Richardson J B

    2007-12-01

    Full Text Available Palynomorphs are abundant in some fine-grained rocks of the Lower Old Red Sandstone (Lower O.R.S. of the Anglo-Welsh Basin. In this study the distribution and relative abundance of sporomorphs (cryptospores and miospores have been examined from samples collected from the uppermost Raglan Marl and St. Maughan’s formations from Ammons Hill and Ross on Wye [Ross-Tewkesbury Spur Motorway (M. 50 Herefordshire in the south and from uppermost Red Downton Formation (Ledbury Formation and Ditton Formation from the Clee Hills (Shropshire in the north (a distance of over 100 km]. The stratigraphical interval examined equates largely to the lower and middle parts of the Lochkovian Stage except in the Clee Hills where the uppermost part of the stage may be present. The Lower O.R.S. sequence in the Anglo-Welsh Basin shows progressive offlap with the migration of medial and proximal facies (fluvial environments to overlie the distal facies (marine-influenced environments in the south. Dispersed palynomorphs have been examined from sections from the distal margins of the floodplain in the south [Ammons Hill and Ross-Tewkesbury Spur Motorway (M. 50 Herefordshire Sections] to more proximal areas of the floodplain in the north (Clee Hills. The relative abundance of major groups of cryptospores and miospores varies stratigraphically in the M. 50 and Clee Hill Sections reflecting the southern migration of facies belts and, although influenced by water transport, sporomorph distribution data may be used with caution to interpret potential habitats of their parent plants. In some cases cryptospores were dominant in sporomorph assemblages from distal sediments, deposited in a marine-influenced coastal plain, and their parent plants may therefore have been halophytic. In contrast, in the more proximal (upstream sediments, except for those from the higher parts of the Brown Clee Hill sequence, cryptospores with granulate to apiculate sculpture and miospores, especially

  9. Patterns of deep-water coral diversity in the Caribbean Basin and adjacent southern waters: an approach based on records from the R/V Pillsbury expeditions.

    Directory of Open Access Journals (Sweden)

    Iván Hernández-Ávila

    Full Text Available The diversity of deep-water corals in the Caribbean Sea was studied using records from oceanographic expeditions performed by the R/V Pillsbury. Sampled stations were sorted according to broad depth ranges and ecoregions and were analyzed in terms of species accumulation curves, variance in the species composition and contributions to alpha, beta and gamma diversity. According to the analysis of species accumulation curves using the Chao2 estimator, more diversity occurs on the continental slope (200-2000 m depth than on the upper continental shelf (60-200 m depth. In addition to the effect of depth sampling, differences in species composition related to depth ranges were detected. However, the differences between ecoregions are dependent on depth ranges, there were fewer differences among ecoregions on the continental slope than on the upper continental shelf. Indicator species for distinctness of ecoregions were, in general, Alcyonaria and Antipatharia for the upper continental shelf, but also the scleractinians Madracis myriabilis and Cladocora debilis. In the continental slope, the alcyonarian Placogorgia and the scleractinians Stephanocyathus and Fungiacyathus were important for the distinction of ecoregions. Beta diversity was the most important component of gamma diversity in the Caribbean Basin. The contribution of ecoregions to alpha, beta and gamma diversity differed with depth range. On the upper continental shelf, the Southern Caribbean ecoregion contributed substantially to all components of diversity. In contrast, the northern ecoregions contributed substantially to the diversity of the Continental Slope. Strategies for the conservation of deep-water coral diversity in the Caribbean Basin must consider the variation between ecoregions and depth ranges.

  10. Plant-water relations in an Andean landscape: Modeling the effect of irrigation on upland crop production

    OpenAIRE

    Zehetner, Franz; Miller, W.

    2003-01-01

    In the inter-Andean valleys of northern Ecuador, irrigation systems have long been used to minimize drought risk and secure the production of food crops during dry periods. However, not all Andean communities have access to irrigation water. Increasing population pressure has forced many peasant farmers to move higher up the volcanic slopes and cultivate more marginal land under rainfed conditions. In the SANREM CRSP research site of Cotacachi, local community members and officials of the loc...

  11. [Gradients, stability and conservation status of fishes in the Andean mountain streams of the Orinoco versant, Venezuela].

    Science.gov (United States)

    Rodríguez-Olarte, Douglas; Barrios Gómez, Margenny

    2014-09-01

    Most Andean mountain streams of the Orinoco Basin in Venezuela, had been suffering various disturbances. In spite of this, fish communities have been poorly evaluated in terms of spatial and temporal gradients. Thus, the generation of information about these communities is a priority, since it may support conservation of regional hydrobiological resources. For this, six sites were monthly evaluated in tributaries of upper Turbio River in Sierra de Portuguesa (770-1,305 msnm), during the dry season and the beginning of the rainy season (January-April 2012); we characterized stream dimensions, substrate and water physicochemical variables. Electrofishing was used to determine the number and abundance of fish species. The fish communities and their stability were evaluated by exploring the changes in richness and abundance, coefficients of variation, hierarchical classification and non-metrical multidimensional scaling analysis. The sites conservation status was estimated with a habitat integrity index. Our results showed that richness of the 12 species found varied accord- ing to the mountain elevation, the tributaries and the conservation status of the sites. Chaetostoma dorsale, Creagrutus taphorni and Chaetostoma milesi comprised 90.8% of the relative abundance, and maintained the first ranks during the study period. The communities had little spatio-temporal variation which was associated with a gradient signed principally by the amount of shadow, rocks and gravel cover, water temperature and conductivity. Stability was moderate but varied with elevation and according to site conservation status. The tributaries in upper Turbio River were found to be under severe impacts and their fishes were found impoverished and at risk. PMID:25412531

  12. Climate-driven terrestrial inputs in ultraoligotrophic mountain streams of Andean Patagonia revealed through chromophoric and fluorescent dissolved organic matter.

    Science.gov (United States)

    Garcia, Roberto D; Reissig, Mariana; Queimaliños, Claudia P; Garcia, Patricia E; Dieguez, Maria C

    2015-07-15

    Fluvial networks transport a substantial fraction of the terrestrial production, contributing to the global carbon cycle and being shaped by hydrologic, natural and anthropogenic factors. In this investigation, four Andean Patagonian oligotrophic streams connecting a forested catchment (~125km(2)) and draining to a double-basin large and deep lake (Lake Moreno complex, Northwestern Patagonia), were surveyed to analyze the dynamics of the allochthonous subsidy. The results of a 30month survey showed that the catchment supplies nutrients and dissolved organic matter (DOM) to the streams. The eruption of the Puyehue-Cordón Caulle at the beginning of the study overlapped with seasonal precipitation events. The largest terrestrial input was timed with precipitation which increased particulate materials, nutrients and DOM through enhanced runoff. Baseline suspended solids and nutrients were very low in all the streams (suspended solids: ~1mg/L; total nitrogen: ~0.02mg/L; total phosphorus: ~5μg/L), increasing several fold with runoff. Baseline dissolved organic carbon concentrations (DOC) ranged between 0.15 and 1mg/L peaking up to three-fold. Chromophoric and fluorescent analyses characterized the DOM as of large molecular weight and high aromaticity. Parallel factor modeling (PARAFAC) of DOM fluorescence matrices revealed three components of terrestrial origin, with certain degree of microbial processing: C1 and C2 (terrestrial humic-like compounds) and C3 (protein-like and pigment derived compounds). Seasonal changes in MOD quality represent different breakdown stages of the allochthonous DOM. Our survey allowed us to record and discuss the effects of the Puyehue-Cordón Caulle eruption, showing that due to the high slopes, high current and discharge of the streams the volcanic material was rapidly exported to the Moreno Lake complex. Overall, this survey underscores the magnitude and timing of the allochthonous input revealing the terrestrial subsidy to food webs in

  13. Population dynamics of Philureter trigoniopsis (Monogenea: Ancyrocephalinae) from urinary organs of Galaxias maculatus (Osmeriformes: Galaxiidae) in a cold temperate Andean Patagonian lake (Argentina).

    Science.gov (United States)

    Viozzi, Gustavo P; Semenas, Liliana G; Gutiérrez, Pablo

    2005-12-01

    Philureter trigoniopsis parasitizes the ureters and urinary bladder of Galaxias maculatus in Patagonian Andean lakes. To investigate factors associated with variation in the prevalence and intensity of this monogenean, fish were sampled periodically over 2 yr in Lake Gutiérrez. Prevalence and mean intensity are higher in smaller fishes than in larger ones. A seasonal pattern was observed, with peak recruitment and peak mean intensity occurring in early spring (September), followed by lows in late summer (January-February). Galaxias maculatus length classes are spatially segregated due to seasonal migrations, so the annual infection cycle is characterized by higher prevalence and intensity from late winter to early summer in the smaller fish from the deep zone of the lake. PMID:16539018

  14. Typical land use pattern in high-mountain landscape - part of the Vysoke Tatry Mts. and the Podtatranska kotlina Basin; map fragment

    International Nuclear Information System (INIS)

    The territory of the Vysoke Tatry (High Tatras) Mts. and the Podtatranska kotlina Basin documents the human impact even in the highest situated parts of Slovakia. The human impact was obvious the same in the past (lowering of the upper timberline and the dwarf pine scrub by grazing) as in the present time (recreation, tourism, and sport). The most frequent wood species of the Tatras forests is the spruce tree. Fir occurs up to the altitude of 1,250 m above sea level. The wood species accompanying the spruce in higher positions are larch, cembra pine, and mountain ash where they form the upper timberline. The mountain dwarf pine scrub creates an independent tier above the upper timber line in the altitude oscillating between 1,550 m and 1,850 m and gradually transits into alpine meadows with rare flora and fauna. The foothill landscape is intensively agriculturally used. The present species composition of the meadows and pastures, as well as their landscape scenery was decisively determined by intensification of farming (adjustments of the terrain, draining of waterlogged areas and spring areas, removal of woody vegetation, creation of disproportionately large fields, sowing of introduced grass species, and the like). It has not only caused the change of the original nature of meadows and pastures, but it has also changed the whole sub-Tatras landscape. (authors)

  15. Multi-scale factors controlling the pattern of floodplain width at a network scale: The case of the Rhône basin, France

    Science.gov (United States)

    Notebaert, Bastiaan; Piégay, Hervé

    2013-10-01

    In this study the floodplain width (FW) was assessed for the entire Rhône catchment river network (32,160 km long) to highlight controlling factors. The FW data, which is measured every kilometre on a digital elevation model (DTM), is aggregated into spatial homogenous segments using a Pettitt break detection test, resulting in aggregated geographical objects (AGO). Based on these AGOs, an analysis of the variability of the floodplain width was performed. The general pattern for the Rhône network shows a downstream increase in FW related to the concept of river continuum. This general pattern explains ca. 30% of the variation in FW. Deviations from this general trend are, however, large. Values for floodplain widths are normalized for catchment scale to study deviations that do not depend on scale effects. Based on a conceptual model, the main environmental parameters influencing FW were identified. These parameters include lithology and different parameters that influence the river profile, such as base level changes and tectonics, sediment load and discharge. An analysis of catchment-wide patterns shows that the main variations on the scaling effect are caused by lithology. Superposed on this general scaling pattern, disturbed by lithological variations, are the variations in floodplain width caused by disturbances in the geomorphic system, which influence floodplain slope, sediment, and water discharge and which include inherited landscapes. Although large data sets become increasingly available and the applied methodology reduces data noise, data availability and quality still hampers studies at a larger scale. Nevertheless, such information sources are becoming crucial because they are more and more accessible and diverse, and the analysis is now easier with the increasing capacities of GIS technologies. As a result, they are becoming very complementary to field studies to understand geomorphic processes at wider spatial and longer temporal scales. In a

  16. Flood-initiating catchment conditions: a spatio-temporal analysis of large-scale soil moisture patterns in the Elbe River basin

    OpenAIRE

    Nied, M.; Hundecha, Y.; Merz, B.

    2013-01-01

    Floods are the result of a complex interaction between meteorological event characteristics and pre-event catchment conditions. While the large-scale meteorological conditions have been classified and successfully linked to floods, this is lacking for the large-scale pre-event catchment conditions. Therefore, we propose classifying soil moisture as a key variable of pre-event catchment conditions and investigating the link between soil moisture patterns and flood occurrence ...

  17. Flood-initiating catchment conditions: a spatio-temporal analysis of large-scale soil moisture patterns in the Elbe river basin

    OpenAIRE

    Nied, M.; Hundecha, Y.; Merz, B.

    2012-01-01

    Floods are the result of a complex interaction between meteorological event characteristics and pre-event catchment conditions. While the large-scale meteorological conditions have been classified and successfully linked to floods, this is lacking for the large-scale pre-event catchment conditions. Therefore, we propose to classify soil moisture as a key variable of pre-event catchment conditions and to investigate the link between soil moisture patterns and flood occurrence in the Elbe ...

  18. Spatial patterns of the congenital heart disease prevalence among 0- to 14-year-old children in Sichuan Basin, P. R China, from 2004 to 2009

    OpenAIRE

    Ma, Li-Guang; Zhao, Jun; Ren, Zhou-Peng; Wang, Yuan-yuan; Peng, Zuo-Qi; Wang, Jin-feng; Ma, Xu

    2014-01-01

    Background Congenital heart disease (CHD) is the most common type of major birth defects in Sichuan, the most populous province in China. The detailed etiology of CHD is unknown but some environmental factors are suspected as the cause of this disease. However, the geographical variations in CHD prevalence would be highly valuable in providing a clue on the role of the environment in CHD etiology. Here, we investigate the spatial patterns and geographic differences in CHD prevalence among 0- ...

  19. Lizards on ice: evidence for multiple refugia in Liolaemus pictus (Liolaemidae during the last glacial maximum in the Southern Andean beech forests.

    Directory of Open Access Journals (Sweden)

    Iván Vera-Escalona

    Full Text Available Historical climate changes and orogenesis are two important factors that have shaped intraspecific biodiversity patterns worldwide. Although southern South America has experienced such complex events, there is a paucity of studies examining the effects on intraspecific diversification in this part of the world. Liolaemus pictus is the southernmost distributed lizard in the Chilean temperate forest, whose genetic structure has likely been influenced by Pleistocene glaciations. We conducted a phylogeographic study of L. pictus in Chile and Argentina based on one mitochondrial and two nuclear genes recovering two strongly divergent groups, Northern and Southern clades. The first group is distributed from the northernmost limit of the species to the Araucanía region while the second group is distributed throughout the Andes and the Chiloé archipelago in Southern Chile. Our results suggest that L. pictus originated 751 Kya, with divergence between the two clades occurring in the late Pleistocene. Demographic reconstructions for the Northern and Southern clades indicate a decrease in effective population sizes likely associated with Pleistocene glaciations. Surprisingly, patterns of genetic variation, clades age and historical gene flow in populations distributed within the limits of the Last Glacial Maximum (LGM are not explained by recent colonization. We propose an "intra-Andean multiple refuge" hypothesis, along with the classical refuge hypothesis previously proposed for the biota of the Chilean Coastal range and Eastern Andean Cordillera. Our hypothesis is supported by niche modelling analysis suggesting the persistence of fragments of suitable habitat for the species within the limits of the LGM ice shield. This type of refuge hypothesis is proposed for the first time for an ectothermic species.

  20. Serum biochemistry in Andean flamingos (Phoenicoparrus andinus): natural versus artificial diet.

    Science.gov (United States)

    Norambuena, M Cecilia; Parada, Mario

    2005-09-01

    A study of 10 clinical pathology values in four groups of Andean flamingo chicks (Phoenicoparrus andinus) was conducted to evaluate an artificial feeding program in Chile. Three groups were fed controlled diets (groups 2000, 2001, and 2002) with quantitative differences in their nutritional content. A fourth group of free-living Andean flamingo chicks was used as normal controls. Nutritional management techniques used in 2002 resulted in hematologic values with similar levels of total protein, globulins, albumin, cholesterol, urea, phosphorus, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, and calcium to those obtained in free-living chicks. In addition, final weight, physical condition, and plumage in flamingo chicks of group 2002 were considered satisfactory to face local climatic conditions and nomadic activity. These results may be useful as reference values and help to improve conservation management and veterinary care of this species. PMID:17312761

  1. Potentially synbiotic product based on Andean blackberry (Rubus glaucus by applying vacuum impregnation

    Directory of Open Access Journals (Sweden)

    Rodríguez-Barona, Sneyder

    2012-12-01

    Full Text Available The aim of this study was to develop a product potentially symbiotic by applying vacuum impregnating over Andean blackberry slices immersed in three solutions: a solution of fructooligosaccharides (FOS, natural blackberry juice, and a mixture of fruit juice and solution of FOS, inoculated with Lactobacillus casei ATCC 393 with 109 UCF/mL. The blackberry slices impregnated with the mixture of fruit juice and FOS, and with just the FOS solution, they were found to contain 108 UCF/g and over 0.0022 g of FOS per 100g of impregnated sample after being stored for 72 hours under refrigeration conditions. The results indicate that the presence of FOS in the impregnation solution increases the viability of the microorganisms and it can be concluded that it is feasible to obtain a potentially symbiotic food from Andean blackberry by means of the impregnation of its porous matrix with beneficial microorganisms and prebiotic substances.

  2. Active Andean volcanism: its geologic and tectonic setting

    Directory of Open Access Journals (Sweden)

    Charles R. Stern

    2004-12-01

    Full Text Available The Andean volcanic arc includes over 200 potentially active Quaternary volcanoes, and at least 12 giant caldera/ignimbrite systems, occurring in four separate segments referred to as the Northern, Central, Southern and Austral Volcanic Zones. Volcanism results from subduction of the Nazca and Antarctic oceanic plates below South America. Active volcanoes occur where the angle of subduction is relatively steep (25°, and active arc segments are separated by regions below which subduction angle decreases and becomes relatively flat (Volcanismo andino activo: marco geológico y tectónico. El arco volcánico andino incluye más de 200 estratovolcanes y, al menos, 12 sistemas de calderas gigantes potencialmente activos, dispuestos en cuatro segmentos separados de la cadena andina conocidos como Zonas Volcánicas Norte, Central, Sur y Austral, y cuya actividad es producto de la subducción de las placas oceanicas Nazca y Antártica bajo la placa sudamericana. Los cuatro segmentos con volcanismo activo ocurren en zonas donde el ángulo de subducción es relativamente inclinado (25°, y entre ellos existen regiones donde el ángulo de subducción es relativamente plano (<10° a profundidades 100 km y el volcanismo está ausente. Las zonas de bajo ángulo de subducción habrían comenzado a formarse durante el Mioceno debido a la subducción de plateaus y dorsales oceánicas, indicando que la actual segmentación de la zona de subducción y el volcanismo andino es un rasgo transitorio relacionado a la actividad tectónica neógena. La relación genética entre subducción y volcanismo ha sido confirmada por estudios geoquímicos que indican que la actividad magmática se inicia por la deshidratación y/o fusión de la litosfera oceánica subductada y la interacción de los fluidos liberados con el manto astenosférico que la sobreyace. Componentes derivados de la corteza continental son también incorporados en los magmas andinos a través de la erosi

  3. Projected distribution shifts and protected area coverage of range-restricted Andean birds under climate change

    OpenAIRE

    Verónica del Rosario Avalos; Jaime Hernández

    2015-01-01

    In this study we projected the effect of anthropogenic climate change in endemic and restricted-range Andean bird species that spread out from the center of Bolivia to southeastern Peru. We also analyzed the representation of these species in protected areas. The ensemble forecasts from niche-based models indicated that 91–100% of species may reduce their range size under full and no dispersal scenarios, including five species that are currently threatened. The large range reduction (average ...

  4. Morphology and DNA sequence data reveal the presence of Globodera ellingtonae in the Andean region

    OpenAIRE

    Lax, P.; Rondan Dueñas, J.C.; Franco-Ponce, J.; Gardenal, C.N.; Doucet, M.E.

    2014-01-01

    Potato cyst nematodes, G. rostochiensis and G. pallida, are the most economically important nematode pests of potatoes worldwide and are subject to strict quarantine regulations in many countries. Globodera ellingtonae was recently described from Oregon (USA), with its host-plant in the field being still unknown. Roots of Andean potatoes from the North of Argentina have been found attacked by this nematode, providing further evidence that this is a potato cyst nematode species, along with G. ...

  5. The Corregidores of the Colca Valley, Peru: Imperial Administration in an Andean Region

    OpenAIRE

    Cook, Noble David

    2003-01-01

    The corregidor de los indios was introduced into the Viceroyalty of Peru by Governor García de Castro in 1565. The institution was designed to limit the power of the encomendero elite and to improve administration and justice in the Andean countryside. Here we examine the impact of the reforms at the local level, the corregimiento of Los Collaguas in the Colca Valley, located between Cuzco and Arequipa. Althought the Crown was largely successful in weakening the encomienda, possibility of gra...

  6. Effects of the hydrological cycle on the phycoperiphyton assemblage in an Andean foothill stream in Colombia

    OpenAIRE

    María I. Ríos-Pulgarín; Isabel C. Gil-Guarín; Mario Barletta; Néstor J. Mancera-Rodríguez

    2016-01-01

    The Guarinó River is a torrential system that is located in the foothills of the Colombian central Andean mountains that naturally experiences severe hydrological disturbances, which were higher during the Niño-Niña/Southern Oscillation (ENSO) between 2007 and 2010. The seasonal and interannual variabilities in the taxonomic composition, richness and density of phycoperiphyton assemblages (ecological descriptors) from the Guarinó River were examined in relation to the physical and chemical en...

  7. Explaining Andean Potato Weevils in Relation to Local and Landscape Features: A Facilitated Ecoinformatics Approach

    OpenAIRE

    Parsa, Soroush; Ccanto, Raúl; Olivera, Edgar; Scurrah, María; Alcázar, Jesús; Rosenheim, Jay A.

    2012-01-01

    Background Pest impact on an agricultural field is jointly influenced by local and landscape features. Rarely, however, are these features studied together. The present study applies a “facilitated ecoinformatics” approach to jointly screen many local and landscape features of suspected importance to Andean potato weevils (Premnotrypes spp.), the most serious pests of potatoes in the high Andes. Methodology/Principal Findings We generated a comprehensive list of predictors of weevil damage, i...

  8. Diaspora Contributions to Democratic Processes at Home: The External Vote of Andean Migrants

    OpenAIRE

    Bermudez Torres, Anastasia; Lafleur, Jean-Michel

    2015-01-01

    This paper focuses on the external vote and wider transnational political participation of Andean migrants from Colombia and Bolivia. Its main aim is to discuss the contributions of these diasporas to democratic and wider political processes in the home countries. The two cases considered offer a good opportunity to do so, since in the last few decades they have put forward new mechanisms for the political inclusion of their nationals abroad, but in different historical, socioeconomic and pol...

  9. Coca: The History and Medical Significance of an Ancient Andean Tradition

    Directory of Open Access Journals (Sweden)

    Amy Sue Biondich

    2016-01-01

    Full Text Available Coca leaf products are an integral part of the lives of the Andean peoples from both a cultural and traditional medicine perspective. Coca is also the whole plant from which cocaine is derived. Coca products are thought to be a panacea for health troubles in regions of South America. This review will examine the toxicology of whole coca and will also look at medicinal applications of this plant, past, present, and future.

  10. Child Malnutrition, Social Development and Health Services in the Andean Region

    OpenAIRE

    LARREA CARLOS; MONTALVO PEDRO; RICAURTE ANA

    2005-01-01

    This study analyzes social, ethnic and regional determinants of child malnutrition, as well as the effects of access to health services in the Andean Region, through a comparison between Ecuador, Peru and Bolivia. These three countries share a profile with high stunting prevalence and strong socio-economic, regional and ethnic disparities. The analysis is conducted using DHS (Peru 1992, 1996 and 2000, Bolivia 1997) and LSMS (Ecuador 1998) surveys and it focuses on an international comparative...

  11. THE ROLE OF COLLECTIVE IDENTITY AND REGIONAL INSTITUTIONS IN THE ANDEAN COMMUNITY

    OpenAIRE

    Prieto Corredor, German Camilo

    2013-01-01

    This thesis analyses the terms in which collective identity and regional institutions can explain state action towards the unfolding of regionalism in the Andean Community (AC). This analysis develops a constructivist approach that assesses constitutive and casual effects of ideas in order to provide explanations. For the assessment and distinction of these effects, the thesis proposes an interpretive method that consists of focusing on transitive verbs and metaphors denoting causation that s...

  12. Transplanting the European Court of Justice: The Experience of the Andean Tribunal of Justice

    OpenAIRE

    Osvaldo Saldías; Laurence R. Helfer; Alter, Karen J.

    2011-01-01

    Although there is an extensive literature on domestic legal transplants, far less is known about the transplantation of supranational judicial bodies. The Andean Tribunal of Justice (ATJ) is one of eleven copies of the European Court of Justice (ECJ), and the third most active international court. This article considers the origins and evolution of the ATJ as a transplanted judicial institution. It first reviews the literatures on legal transplants, neofunctionalist theory, and the spread of ...

  13. Inter-basin dynamics on multidimensional potential surfaces. I. Escape rates on complex basin surfaces

    Science.gov (United States)

    Despa, Florin; Berry, R. Stephen

    2001-11-01

    In this report, we present a general prescription for computing the escape rate of the system from a basin with full consideration of the topographical fingerprint of that basin. The method is based on a solution of the reduced Fokker-Planck equation and built up to allow the separation of the inter-basin dynamics from that of the intra-basin motion. The main result is that when local well populations thermalize within a basin, local minima, especially those of higher energy, enhance the escape rate from the basin. Also, numerical analyses lead to the inference that kinetic traps of "wrong" structures are distinctive topographical patterns which may produce kinetic properties similar to those of the primary basin, i.e., that containing the global minimum, but lie in other basins.

  14. Impacts of warm and cold situations in the Mediterranean basins on the West African monsoon: observed connection patterns (1979-2006) and climate simulations

    Energy Technology Data Exchange (ETDEWEB)

    Fontaine, Bernard; Roucou, Pascal; Sijikumar, Sivarajan [CNRS/University of Burgundy, Centre de Recherches de Climatologie, Dijon (France); Garcia-Serrano, Javier; Rodriguez-Fonseca, Belen; Losada, Teresa [Universidad Complutense de Madrid, Madrid (Spain); Chauvin, Fabrice [CNRS/Meteo-France, Centre National de Recherches Meteorologiques, Toulouse (France); Gervois, Sebastien; Janicot, Serge [CNRS/IRD/Paris VI, Institut Pierre-Simon Laplace/LOCEAN, Paris (France); Ruti, Paolo [Environmental and Energy Research Institute, Rome (Italy)

    2010-07-15

    Using both empirical and numerical ensemble approaches this study focuses on the Mediterranean/West African relationship in northern summer. Statistical analyses utilize skin temperature, sea surface temperature, in situ and satellite rainfall, outgoing longwave radiation (OLR) observations and reanalyzed data winds and specific humidity on isobaric surfaces. Numerical investigations are based on a large set of sensitivity experiments performed on four atmospheric general circulation models (AGCM): ARPEGE-Climat3, ECHAM4, LMDZ4 and UCLA7.3. Model outputs are compared to observations, discussed model by model and with an ensemble (multi-model) approach. As in previous studies the anomalous Mediterranean warm events are associated with specific impacts over the African monsoon region, i.e., a more intense monsoon, enhanced flux convergence and ascendances around the ITCZ, a strengthening of low level moisture advection and a more northward location of ascending motion in West Africa. The results show also new features (1) thermal variability observed in the two Mediterranean basins has unalike impacts, i.e. the western Mediterranean covaries with convection in Gulf of Guinea, while the eastern Mediterranean can be interpreted as Sahelian thermal-forcing; (2) although observations show symmetry between warming and cooling, modelling evidences only support the eastern warming influence; (3) anomalous East warm situations are associated with a more northward migration of the monsoon system accompanied by enhanced southwertely flow and weakened northeasterly climatological wind; (4) the multi-model response shows that anomalous East warm surface temperatures generate an enhancement of the overturning circulation in low and high levels, an increase in TEJ (Tropical Eeasterly Jet) and a decrease in AEJ (African Eeasterly Jet). (orig.)

  15. Agronomic performance and stability of andean common bean lines with white grains in Brazil

    Directory of Open Access Journals (Sweden)

    Helton Santos Pereira

    2014-06-01

    Full Text Available This work evaluated the effect of genotype by environment interaction in Andean common bean lines with white grains, in Central Southern Brazil, to identify lines with high agronomic performance, stability and adaptability, aiming to meet domestic demand and to increase the Brazilian participation in the foreign market of common bean. Nineteen trials with twelve Andean lines were conducted in 2007, 2008 and 2009, in Central Southern Brazil. Grain yield and other agronomic traits were evaluated. Data were subjected to analysis of variance and of adaptability/stability using Annicchiarico and modified AMMI methods. Significant differences were found between lines for all traits evaluated. Genotype by environment interaction was important for lines with Andean origin and white seed. The utilization of weighted mean of absolute scores and yield with the AMMI results enabled the identification of the most stable and adapted lines. Lines Poroto Alubia, CNFB 16211, Ouro Branco and WAF 160 were stable and adapted, using both methods. CNFB 16211 line presented high agronomic performance, stability and adaptability and therefore this line may be a new cultivar. USWA 70 and WAF 75 lines presented grain size similar to that required by the foreign market and superior to the Brazilian cultivars, besides favorable agronomic traits, and thus these lines may be indicated as new cultivars.

  16. Preliminary phylogenetic analysis of the Andean clade and the placement of new Colombian blueberries (Ericaceae, Vaccinieae

    Directory of Open Access Journals (Sweden)

    Paola Pedraza-Penalosa

    2015-04-01

    Full Text Available The blueberry tribe Vaccinieae (Ericaceae is particularly diverse in South America and underwent extensive radiation in Colombia where many endemics occur. Recent fieldwork in Colombia has resulted in valuable additions to the phylogeny and as well in the discovery of morphologically noteworthy new species that need to be phylogenetically placed before being named. This is particularly important, as the monophyly of many of the studied genera have not been confirmed. In order to advance our understanding of the relationships within neotropical Vaccinieae and advice the taxonomy of the new blueberry relatives, here we present the most comprehensive phylogenetic analysis for the Andean clade. Anthopterus, Demosthenesia, and Pellegrinia are among the putative Andean genera recovered as monophyletic, while other eight Andean genera were not. The analyses also showed that genera that have been traditionally widely defined are non-monophyletic and could be further split into more discrete groups. Four newly discovered Colombian Vaccinieae are placed in the monophyletic Satyria s.s. and the Psammisia I clade. Although these new species are endemic to the Colombian Western Cordillera and Chocó biogeographic region and three are not known outside of Las Orquídeas National Park, they do not form sister pairs.

  17. Production and use of the pastures of the Colombia high Andean areas

    International Nuclear Information System (INIS)

    A relationship of the most common pastures is made in the Andean high area between the 2000 and 3000 m.s.n.m. and of their native vegetable associations, as well as of the invaders plants and overgrowths. The gramineae germoplasm and leguminous is indicated that has been proven lower those conditions. Data of yield average of dry matter are presented for native and introduced grasses of cold climate in Colombia. Equally it is indicated the daily earnings by animal, the load capacity and the animal production with different fertilization systems and some parameters of productivity are shown of gramineous and leguminous introduced in the high areas of Colombia. The nutritious value of gramineous and leguminous of cold climate and its chemical composition are made. A description is made of the ecological areas of the Andean high area and the pastures types that prevail in them. The factors are described that they impact in the degree of deterioration of the pastures like the environment, the same grass, the handling, the livestock, the type of exploitation, the holding of the earth and the administration. The agricultural production systems are mentioned that are associate the Andean pastures, as well as the main obstacles to increase the production of the systems and pastures and their possible solutions

  18. Endemic epigean Tenebrionids (Coleoptera: Tenebrionidae) from the Andean Region: exploring the patagonian-diversification hypothesis.

    Science.gov (United States)

    Carrara, Rodolfo; Flores, Gustavo E

    2015-01-01

    Tenebrionidae is a diverse insect family of Coleoptera that shows high levels of endemicity in epigean species. For the Andean region, which is divided into three subregions: Central Chilean, Subantarctic and Patagonian, it has been hypothesized that epigean tenebrionids have diversified in the Patagonian subregion and subsequently, they dispersed to Subantarctic and Central Chilean subregions. In this work, based on information obtained from museum collections and scientific studies, we presented the first list of endemic epigean tenebrionids from the Andean region with their taxonomic arrangement and geographic distribution. Moreover, we used these data to explore the veracity of the Patagonian-diversification hypothesis. A total of 416 species grouped into six subfamilies, 17 tribes and 41 genera were identified as endemic to the Andean region. Considering the spatial distribution it was observed that subfamilies, tribes, genera and species were unequally distributed across subregions. Results did not support the Patagonian-diversification hypothesis; to the contrary, they were more concordant with processes of isolation among subregions that have promoted speciation by interrupting gene flow among populations, resulting in endemism because species can not expand their range sizes. Finally, we discuss the implications of our findings to be considered in biodiversity conservation, because endemic species, by their high extinction risk, are primary targets in conservation strategies. PMID:26623788

  19. Transplanting the European Court of Justice: The Experience of the Andean Tribunal of Justice

    Directory of Open Access Journals (Sweden)

    Osvaldo Saldías

    2011-05-01

    Full Text Available Although there is an extensive literature on domestic legal transplants, far less is known about the transplantation of supranational judicial bodies. The Andean Tribunal of Justice (ATJ is one of eleven copies of the European Court of Justice (ECJ, and the third most active international court. This article considers the origins and evolution of the ATJ as a transplanted judicial institution. It first reviews the literatures on legal transplants, neofunctionalist theory, and the spread of European ideas and institutions, explaining how the intersection of these literatures informs the study of supranational judicial transplants. The article next explains why the Andean Pact's member states decided to add a court to their regional integration initiative, why they adapted the European Community model, and how the ECJ's existence has shaped the evolution of Andean legal doctrine and the political space within which the ATJ operates. We conclude by analyzing how the ATJ's experience informs the challenges of supranational transplants and theories of supranational legal integration more generally. DOWNLOAD THIS PAPER FROM SSRN: http://ssrn.com/abstract=1948405

  20. Deep seismic structure of the Atacama basin, northern Chile

    Science.gov (United States)

    Schurr, B.; Rietbrock, A.

    2004-06-01

    The Atacama basin is a prominent morphological anomaly in the Central Andean forearc. 3D seismic structure beneath the depression and its surroundings has been determined from local earthquake tomography. Depth maps of P-wave velocity and attenuation (1/Qp) through the lithosphere reveal a rheologically strong (high Qp and vp) lithospheric block beneath the basin, surrounded by weak regions (low Qp and vp) beneath Pre- and Western Cordilleras. The anomalous lithospheric structure appears to bar hot asthenospheric mantle from penetrating trenchward, and hence causes the volcanic front to be deflected by the Salar de Atacama basin. The cold block may also influence the thermal structure of the subducted slab causing reduced Benioff seismicity and less hydration of mantle rocks evident from reduced vp/vs ratios. Seismic data are hard to reconcile with extension and lithospheric thinning as a mechanism for subsidence of the basin. Instead, high strength of the Atacama lithospheric block may contribute to basin formation by focussing deformation and uplift along the block's weak edges.

  1. Decadal-scale export of nitrogen, phosphorus, and sediment from the Susquehanna River basin, USA: Analysis and synthesis of temporal and spatial patterns.

    Science.gov (United States)

    Zhang, Qian; Ball, William P; Moyer, Douglas L

    2016-09-01

    The export of nitrogen (N), phosphorus (P), and suspended sediment (SS) is a long-standing management concern for the Chesapeake Bay watershed, USA. Here we present a comprehensive evaluation of nutrient and sediment loads over the last three decades at multiple locations in the Susquehanna River basin (SRB), Chesapeake's largest tributary watershed. Sediment and nutrient riverine loadings, including both dissolved and particulate fractions, have generally declined at all sites upstream of Conowingo Dam (non-tidal SRB outlet). Period-of-record declines in riverine yield are generally smaller than those in source input, suggesting the possibility of legacy contributions. Consistent with other watershed studies, these results reinforce the importance of considering lag time between the implementation of management actions and achievement of river quality improvement. Whereas flow-normalized loadings for particulate species have increased recently below Conowingo Reservoir, those for upstream sites have declined, thus substantiating conclusions from prior studies about decreased reservoir trapping efficiency. In regard to streamflow effects, statistically significant log-linear relationships between annual streamflow and annual constituent load suggest the dominance of hydrological control on the inter-annual variability of constituent export. Concentration-discharge relationships revealed general chemostasis and mobilization effects for dissolved and particulate species, respectively, both suggesting transport-limitation conditions. In addition to affecting annual export rates, streamflow has also modulated the relative importance of dissolved and particulate fractions, as reflected by its negative correlations with dissolved P/total P, dissolved N/total N, particulate P/SS, and total N/total P ratios. For land-use effects, period-of-record median annual yields of N, P, and SS all correlate positively with the area fraction of non-forested land but negatively with

  2. DNA sequence characterisation and phylogeography of Lymnaea cousini and related species, vectors of fascioliasis in northern Andean countries, with description of L. meridensis n. sp. (Gastropoda: Lymnaeidae

    Directory of Open Access Journals (Sweden)

    Bargues M Dolores

    2011-07-01

    Full Text Available Abstract Background Livestock fascioliasis is a problem throughout Ecuador, Colombia and Venezuela, mainly in Andean areas where the disease also appears to affect humans. Transmission patterns and epidemiological scenarios of liver fluke infection have shown to differ according to the lymnaeid vector snail species involved. These Andean countries present the vectors Lymnaea cousini, L. bogotensis and L. ubaquensis, unknown in the rest of Latin America. An exhaustive combined haplotype study of these species is performed by means of DNA sequencing of the nuclear ribosomal 18S RNA gene, ITS-2 and ITS-1, and mitochondrial DNA cox1 gene. Results The conserved 5.8S rDNA sequence corroborated that no pseudogenes are involved in the numerous non-microsatellite/minisatellite-related indels appearing between the ITS-2 and ITS-1 sequences when comparing different L. cousini - L. bogotensis populations. Sequence analyses and phylogenetic reconstruction methods including other lymnaeid vector species show that (i L. bogotensis is a synonym of L. cousini, (ii L. ubaquensis is a synonym of Pseudosuccinea columella, and (iii populations of L. cousini hitherto known from Venezuelan highlands indeed belong to a new species for which the name L. meridensis n. sp. is proposed. This new species is described and a complete phenotypic differentiation provided. Conclusions ITS-2, ITS-1 and cox1 prove to be good markers for specimen classification and haplotype characterisation of these morphologically similar lymnaeids in endemic areas. Analysis of the 18S gene and phylogenetic reconstructions indicate that L. cousini and L. meridensis n. sp. cluster in an evolutionary line different from the one of P. columella, despite their external resemblance. This suggests an evolutionary phenotypic convergence related to similar environments and which has given rise to frequent specimen misclassification. Body size and phylogenetic relationships of L. meridensis n. sp. with

  3. Circadian chronotypes among wild-captured west Andean octodontids

    Directory of Open Access Journals (Sweden)

    ADRIÁN OCAMPO-GARCÉS

    2006-01-01

    Full Text Available Rest activity pattern was studied in wild-captured males of Octodon degus (n=9, Octodon bridgesi (n=3, and Spalacopus cyanus (n=6 (Rodentia: Octodontidae. Ten-minute resolution actograms were constructed from data obtained by an automated acquisition system. After two months of habituation to a stable light-dark schedule, recordings were performed in isolation chambers under a 12: 12 Light Dark schedule. A free-running period (constant darkness was recorded for O. bridgesi and S. cyanus. O. degus displayed a crepuscular pattern of rest activity rhythm. Entrained O. bridgesi and S. cyanus displayed nocturnal preference, with rest anticipating light phase and without crepuscular activity bouts. Under constant darkness, active phase occurred at subjective night in O. bridgesi and S. cyanus. Wild-captured O. bridgesi and S. cyanus possess a circadian driven nocturnal preference, while wild O. degus displays a crepuscular profile. Diurnal active phase preference of wild S. cyanus colonies observed in the field could not be explained solely by photic entrainment, since social and/or masking processes appear to be operative. The genus Octodon includes species with diverse chronotypes. We propose that crepuscular diurnal pattern observed in O. degus is a recent acquisition among the octodontid lineage

  4. The feedback between active tectonics, fluid flow and mineralization in an Andean geotermal reservoir

    Science.gov (United States)

    Reich, M.; Arancibia, G.; Perez, P.; Sanchez, P.; Cembrano, J. M.; Stimac, J. A.; Lohmar, S.

    2012-12-01

    In the Andean Cordillera of Central-Southern Chile, geothermal resources occur in close spatial relationship with active volcanism. The nature of the relationship between tectonics and volcanism in this region is the result of interaction between the crustal structures of the basement and the ongoing regional stress field, which is primarily controlled by the oblique convergence of the Nazca and South America Plates. Between 39° and 46°S, the volcanic and geothermal activity is controlled by the NNE-trending, 1,000 km long Liquiñe-Ofqui Fault Zone (LOFZ), an intra-arc dextral strike-slip fault system. Although there is consensus that volcanism (and hence geothermal activity) in southern Chile is largely controlled by the regional-scale tectonic stress field and architecture of the volcanic arc, there is limited scientific information about the role of local kinematic conditions on fluid flow and mineralization during the development and evolution of geothermal reservoirs. In this report, we present the preliminary results of an undergoing structural, mineralogical and geochemical study of the Tolhuaca geothermal system in southern Chile. The Tolhuaca geothermal reservoir formed as a liquid-dominated hydrothermal system, where shallow upflow resulted in near-boiling temperatures in a roughly horizontal liquid reservoir at 100-200 m depth (Melosh et al., 2010, 2012). In an early stage of evolution, hydrothermal brecciation and phase-separation (boiling) episodes penetrated at least 950 m depth into the deeper reservoir, and boiling was followed by steam-heated water invasion that cooled the reservoir. In a later stage, the preliminary conceptual model involves boiling and reheating of the reservoir, forming a system with deep hot brines that is connected to the shallow steam zone by an upflow conduit that is characterized by high-temperature mineralogy. The structural analysis of veins, fault-veins and faults of the Tol-1 drillcore (~1080 m depth) provide insights

  5. Soil organic matter dynamics at the paramo and puna highlands in the Andean mountains

    Science.gov (United States)

    Ángeles Muñoz, M.; Faz, Ángel; Mermut, Ahmet R.; Zornoza, Raúl

    2014-05-01

    Mountains and uplands represent the most diverse and fragile ecosystems in the world, cover about 20% of the terrestrial surface and are distributed across all continents and major ecoregions. The Andean Plateau is the main mountain range of the American continent and one of the largest in the world with more than 7,500 km. The soil organic matter is a corner stone in the fertility management of the Andean agriculture as well as in the erosion control. However, its role is still much unknown in these ecosystems. Moreover, the influence of current global climatic change on soil organic C reservoirs and dynamics is still not clearly understood. The aim of this work was to review the soil C dynamics and the implication of the soil organic matter in the fertility management, erosion control, conservation of biodiversity and global climate change to improve the knowledge on the mountain Andean highlands. Climate, landscape, soil C pools, biomass and management were studied. In general, the Andean climate is affected by three main factors: ocean currents, winds and orography characterized by an abrupt topography. The entire Andean belt is segmented into the Northern, Central and Southern Andes. Northern Andes are called paramo and are characterized by humid climate while Central and Southern Andes dryer zones are called puna. Most of the region is tectonically and volcanically active. Sedimentary rocks predominated in the paramo while sedimentary, igneous and metamorphic ones prevailed in the puna. The most common soils were Andosols, Regosols, Umbrisols and Histosols. The cold and wet climate and the low atmospheric pressure favored organic matter accumulation in the soil. The accumulation of organic matter is further enhanced by the formation of organomineral complexes strongly resistant to the microbial breakdown mainly in the paramo. High organic C contents were observed in the paramo (10%) oppositely to the low contents found in the dryer puna (1%). The C/N ratio

  6. Vinna Basin

    Czech Academy of Sciences Publication Activity Database

    Honěk, J.; Franců, J.; Mikuláš, Radek; Pešek, J.; Sýkorová, Ivana; Tomanová-Petrová, P.

    Prague: Czech Geological Survey, 2014, s. 223-241 ISBN 978-80-7075-862-5 R&D Projects: GA ČR GA105/06/0653 Institutional support: RVO:67985891 ; RVO:67985831 Keywords : Tertiary basins * Czech Republic * Cenomanian and Tertiary lignite * geology * stratigraphy Subject RIV: DB - Geology ; Mineralogy

  7. Development of a Dynamic Downscaling strategy for Ganga Basin and Investigation of the Hydrological Pattern C. Chaudhuri, R Srivastava, and S N Tripathi Department of Civil Engineering, Indian Institute of Technology Kanpur

    Science.gov (United States)

    Chaudhuri, C.; Srivastava, R.; Tripathi, S. N.

    2012-12-01

    Climate and hydrological cycle of any region interact with each other in a highly complex and non-linear fashion. India has a unique weather distribution over her geography, generated due the interaction of the synoptic scale atmospheric flow, diversity of local topography, vegetation, climatic conditions, and high population density, etc. . In regional scale hydrological modeling, this interaction between the large scale climate and local scale hydrological cycle is considered as one of the major driving factors. The Weather Research and Forecasting (WRF) model is a numerical weather prediction and atmospheric simulation system designed to resolve this interaction at regional scale. We study the state of climatic condition as well hydrological cycle over the Ganga basin during long term simulation using WRF. A single domain with a resolution of 27 km was used to cover the whole of India and the region of interest and validation is the entire Ganga basin. Model is integrated for year 2010. We investigated the impact of different data sets of SST (Final Analysis FNL and Real-time Global RTG), input files prepared from FNL and Climate Forecast System reanalysis (CFSR), parameterizations (convective, microphysical, boundary layer, radiation and land surface), domain size, domain resolution and number of vertical levels on the simulation of near surface meteorological fields and identified the combination that "best" reproduces the observed characteristics of near surface atmospheric variables. The best configuration is used to time integrate 3 years (2008-2010) of which 2008 was weak drought, 2009 was a massive drought and 2010 was a normal monsoon year. We performed the downscaling for these years with three configurations: (1) one continuous time integration with single initialization, (2) single initialization but with 3-D nudging with relaxation of PBL, (3) same as 2 but with spectral nudging relaxation.The spatial patterns of rainfall are compared with TRMM 3B42v

  8. The distribution pattern of trace elements in Pedra do Fogo formation, permian of Maranhao Basin and it application as an environment indicator of sedimentation

    International Nuclear Information System (INIS)

    The present investigation consisted of a geochemical study of the medium and upper layers of the Pedra do Fogo Formation aiming at correlating its elemental distribution pattern with the sedimentary environment where that formation was deposited. Pelitic material with carbonate content below 30% was sampled in the three different outcrops of the Pedra do Fogo Formation for mineralogical and chemical analyses. Illite and dolomite, with subordinate amounts of smectite, calcite, quartz and K-feldspar were determined by X-ray diffraction techniques as the constituents of the mineral assemblages. Trace element (B, Ba, Co, Cr, Cu, Ga, Li, Mn, Ni, P, V, Pb, Sr, Rb and Zn), CO sub(2) and K concentrations were determined by emission spectrography, atomic absorption spectrometry and colorimetry. The interpretation of the chemical data based on B-V, Ga-B, B-K sub(2) O and B-Ga-Rb diagrams and on B content indicates a wite range of variation for the medium salinity during the deposition of the Pedra do Fogo rocks. Accordingly, the observed sequence is composed of intercalations of marine and fresh water sediments, the latter being dominant. The marine intercalations are more frequent in the bottom of the sampled stratigraphic section and become progressively rarer towards the top layers which were deposited in a typically fresh water environment. (author)

  9. Regulations and patterns of soil moisture dynamics and their controlling factors in hilly regions of lower reaches of Yangtze River basin, China

    Institute of Scientific and Technical Information of China (English)

    余蔚青; 王玉杰; 胡海波; 王云琦; 张会兰; 王彬; 刘勇

    2015-01-01

    Time-domain reflectometry was used to make continuous measurements of soil moisture to 18 sample points with depth of 2 m for 36 months in a typical artificial secondary oak forest located in a hilly area on Zijin Mountain in the suburbs of Nanjing, China. The data were then used to examine the patterns of soil moisture variations on temporal and spatial scales and predict the relationships between soil moisture and major factors of both meteorology and topography. Water in the topsoil was active, and the upper 30 cm of soil supplied about 43% of the water content variation during the whole year. This difference of water content changes among layers could be due to the distribution conditions of some soil physical properties. When initial soil moisture was in the range from 10% to 40%, the impact of a single storm event on soil moisture was extremely significant, especially on sunny slope. Both climate and slope condition were related to soil moisture change, and the impact of slope gradient on soil moisture was higher that on shady slope. Moreover, root uptake was another important path of soil water consumption.

  10. The Sequence Architecture of Volcanic Basin Fillings- An Example From Xujiaweizi Faulted Depression In Songliao Basin

    Institute of Scientific and Technical Information of China (English)

    CHENG Rihui; LIU Wanzhu; SHAN Xuanlong; WANG Pujun; CHEN Shumin; QU Yongbao

    2001-01-01

    The basin filling geometric pattern of volcanic eruptive rocks depends on both of the eruptive locations in a basin and structural styles of fault terraces. It is divided into three types by eruptive locations and occurrences of eruptive rocks, including the pattern of eruption along fault and occurrence (PEAFO), the pattern of eruption on footwall of a fault and occurrence (PEOFO) and the pattern of eruption on hangingwall of fault and occurrence (PEOHO) in Xujiaweizi fault depression of Songliao basin, Northeast of China. Those basin filling patterns of volcanic eruptive rocks are of specific geometric characteristics controlling or affecting sedimentation, geometry of sedimentary body and sequence architecture during a sequence evolution. The study shows that the volcanic rocks developed at different stages of lowstand, transgressive and highstand can give different controls or affects on the sequence architecture.

  11. 近20年来伊洛河流域典型地区森林景观格局动态%Forest landscape patterns dynamics of Yihe-Luohe river basin

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Based on the information from forest resources distribution maps of Luoning County of1983 and 1999, six indices were used to analyze spatial patterns and dynamics of forest landscapesof the typical region in the middle of the Yihe-Luohe river basin. These indices include patchnumber, mean patch area, fragment index, patch extension index, etc. The results showed that: (1)There was a rapid increase in the number of patch and total area from 1983 to 1999 in the studyarea. The fragment degree became very high. (2) The area of all the forest patch types had witnessedgreat changes. The fractal degree of each forest patch type became big from 1983 to 1999. The meanextension index of Robinia pseudoacacia forest, non-forest, shrub forest, sparse forest, and Quercusspecies forest increased rapidly, but that of economic forest became zero. The fractal dimension eachshowed that forest coverage has been promoted. (3) The changes of landscape patterns were differentin different geomorphic regions. From 1983 to 1999 the vegetation cover area, the gross number andthe density of patch, diversity and evenness of landscape were all reduced greatly in gullies andravines, but the maximum area and the mean area of patch types were increased. In hilly region,both the forest cover area and the number of patch increased from 1983 to 1999, but the mean areaof patch was reduced greatly. In mountain region, even though the area under forest canopy reducedfrom 1983 to 1999, the patch number was increased greatly, the mean area of all patch types wasreduced, the extension index, diversity index and evenness index of landscape were all increased.Furthermore, because of different types of land use, human activity and terrain, the vegetationchanges on northern and southern mountain slopes were different. According to these analyses, themain driving forces, such as the policies of management, market economy, influence of humanactivities etc. are brought out.

  12. North-south Differentiation of the Hydrocarbon Accumulation Pattern of Carbonate Reservoirs in the Yingmaili Low Uplift, Tarim Basin,Northwest China

    Institute of Scientific and Technical Information of China (English)

    L(U) Xiuxiang; LI Jianjiao; ZHAO Fengyun; YANG Ning; ZHANG Qiucha

    2008-01-01

    By analyzing the characteristics of development, structural evolution and reservoir beds of the residual carbonate strata, this study shows that the residual carbonate strata in the Yingmaili low uplift are favorable oil and gas accumulation series in the Tabei (northern Tarim uplift) uplift. There are different patterns of hydrocarbon accumulation on the northern and southern slopes of the Yingmaili low uplift. The north-south differentiation of oil reservoirs were caused by different lithologies of the residual carbonate strata and the key constraints on the development of the reservoir beds. The Mesozoic terrestrial organic matter in the Kuqa depression and the Palaeozoic marine organic matter in the Manjiaer sag of the Northern depression are the major hydrocarbon source rocks for the northern slope and southern slope respectively. The hydrocarbon accumulation on the northern and southern slopes is controlled by differences in maturity and thermal evolution history of these two kinds of organic matter. On the southern slope, the oil accumulation formed in the early stage was destroyed completely, and the period from the late Hercynian to the Himalayian is the most important time for hydrocarbon accumulation. However, the time of hydrocarbon accumulation on the northern slope began 5 Ma B.P. Carbonate inner buried anticlines reservoirs are present on the southern slope, while weathered crust and paleo-buried hill karst carbonate reservoirs are present on the northern slope. The northern and southern slopes had different controlling factors of hydrocarbon accumulation respectively. Fracture growth in the reservoir beds is the most important controlling factor on the southern slope; while hydrocarbon accumulation on the northern slope is controlled by weathered crust and cap rock.

  13. The hydrological regime of a forested tropical Andean valley

    Directory of Open Access Journals (Sweden)

    K. E. Clark

    2014-07-01

    Full Text Available The hydrology of tropical mountain catchments plays a central role in ecological function, geochemical and biogeochemical cycles, erosion and sediment production, and water supply in globally important environments. There have been few studies quantifying the seasonal and annual water budgets in the montane tropics, particularly in cloud forests. We investigated the water balance and hydrologic regime of the Kosñipata Valley (basin area 164.4 km2 over the period 2010–2011. The valley spans over 2500 m in elevation in the eastern Peruvian Andes and is dominated by tropical montane cloud forest with some high elevation puna grasslands. Catchment wide rainfall was 3028 ± 414 mm yr−1, calculated by calibrating Tropical Rainfall Measuring Mission (TRMM 3B43 rainfall with rainfall data from 9 meteorological stations in the valley. Cloud water input to streamflow was 316 ± 116 mm yr−1 (~10% of total inputs, calculated from an isotopic mixing model using deuterium excess (Dxs and δD of waters. Field stream flow was measured in 2010 by recording height and calibrating to discharge. River runoff was estimated to be 2796 ± 126 mm yr−1. Actual evapotranspiration (AET was 909 ± 182 mm yr−1, determined using the Priestley and Taylor – Jet Propulsion Laboratory (PT-JPL model. The overall water budget was balanced within 10%. Relationships between monthly rainfall and river runoff follow an anti-clockwise hysteresis through the year, with a persistence of high runoff after the end of the wet season. The size of the soil- and shallow ground-water reservoir is most likely insufficient to explain sustained dry season flow. Thus, the observed hysteresis in rainfall-runoff relationships is best explained by sustained groundwater flow in the dry season, which is consistent with the water isotope results that suggest persistent wet season sources to stream flow throughout the year. These results demonstrate the importance of transient groundwater

  14. Tropical Andean forest derives calcium and magnesium from Saharan dust

    Science.gov (United States)

    Boy, Jens; Wilcke, Wolfgang

    2008-03-01

    We quantified base metal deposition to Amazonian montane rain forest in Ecuador between May 1998 and April 2003 and assessed the response of the base metal budget of three forested microcatchments (8-13 ha). There was a strong interannual variation in deposition of Ca [4.4-29 kg ha-1 a-1], Mg [1.6-12], and K [9.8-30]). High deposition changed the Ca and Mg budgets of the catchments from loss to retention, suggesting that the additionally available Ca and Mg was used by the ecosystem. Increased base metal deposition was related to dust outbursts of the Sahara and an Amazonian precipitation pattern with trans-regional dry spells allowing for dust transport to the Andes. The increased base metal deposition coincided with a strong La Niña event in 1999/2000.

  15. Unraveling multiple provenance areas using sandstone petrofacies and geochemistry: An example in the southern flank of the Golfo San Jorge Basin (Patagonia, Argentina)

    Science.gov (United States)

    Limarino, Carlos Oscar; Giordano, Sergio Roberto

    2016-03-01

    The aim of this paper is to study the provenance of Late Cretaceous sandstones deposited along the south flank of the Golfo San Jorge Basin. For this purpose, detrital modes of three hundred thirty-seven sandstone samples collected in the Mina del Carmen, Bajo Barreal, and Cañadón Seco Formations were studied in ten oil fields. According to the modal composition of the sandstones, six petrofacies were defined allowing the identification of not only principal, but also secondary provenance areas. The QVM and VQM petrofacies are more than 20% metamorphic, sedimentary, and polycrystalline quartz clasts (Lm + Ls + Qpg > 20%), evidencing a secondary signal of basement supply masked by a predominant volcanic provenance. The petrofacies VP and VF are characterized by Lm + Ls + Qpg 20%.), which indicate a supply of sediment from volcanic terrains and scarce derivation of materials from basement rocks. Based on the plagioclase/k-feldspar ratio, the VF petrofacies is interpreted to be dominated by the supply of sand grains from the Andean volcanic-arc, while VP is supposed have originated through the erosion of intermediate volcanic rock outcroppings in the Macizo del Deseado. Finally, both the VQ and QV petrofacies show Lm + Ls + Qpg <20% and Pm + Om<20%, indicating a provenance of volcanic areas coupled with minor contributions from basement rocks. During the Late Cretaceous, the Golfo San Jorge Basin underwent a sag phase that was characterized by very scarce volcanism and tectonic activity. Although these conditions did not favor defined patterns in the vertical stacking of petrofacies, the sandstones exhibit remarkable changes in their regional distribution, which were determined by the paleogeography of the basin and differences in basement composition within the source areas. Finally, a paleogeographic model for sediment circulation in the basin is proposed. This model recognizes the main fluvial dispersal trends that flowed northwest to southeast and transported

  16. Regional evaluation of the hydrocarbon potential for the South American thrust belts and adjacent foreland basins

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, J.; Cook, J.; Davis, M.; Eggers, L.; Spencer, S.; Toadvine, S. [Amoco Worldwide Exploration Business Group, Houston, TX (United States)

    1996-08-01

    The hydrocarbon potential of the Andean thrust belts and adjacent foreland basins is varied and made complicated by regional-scale changes in stratigraphy and accompanying structural style. These changes appear to be controlled by an inherited Paleozoic structural grain and an early Mesozoic rifting fabric. Accompanying these factors are variations in source rock and evaporate distribution. Understanding the variability in the exploration and exploitation potential of the Andes is facilitated by a comparison with other thrust and fold belts from around the world. Using an integrated, modular approach, we have analyzed 27 petroliferous thrust belts and adjacent foreland basins from around the world to study the wide variety within these petroleum systems and their associated geotechnical risks. This global study indicates that the essential factors of productive systems are the volume and distribution of effective source rocks in conjunction with the timing of hydrocarbon generation, migration, and entrapment. This timing varies extensively from north to south. Hence, what works in one portion of the belt may not work in another. Integration of a global study of well-documented thrust belts and foreland basins systems with an Andean exploration or exploitation study helps narrow the range of possible interpretations developed from minimal data commonly available prior to bid rounds. It also helps in field exploitation and deeper pool wildcat exploration by suggesting new trap type potential.

  17. Along-strike variability of back-arc basin collapse and the initiation of sedimentation in the Magallanes foreland basin, southernmost Andes (53-54.5°S)

    Science.gov (United States)

    McAtamney, Janelle; Klepeis, Keith; Mehrtens, Charlotte; Thomson, Stuart; Betka, Paul; Rojas, Lisandro; Snyder, Shane

    2011-10-01

    The Patagonian Andes record the Cretaceous demise of the quasi-oceanic Rocas Verdes back-arc basin and formation of the Magallanes foreland basin. For >500 km along the strike of the mountains, this tectonic transition is marked by a sandstone-mudstone package that records the beginning of turbiditic sand deposition and fan growth. Sandstone modal analyses and U-Pb detrital zircon spectra show changes in rock composition and provenance across the transition on a basin-wide scale, indicating it has tectonic significance and is related to orogenic uplift and the progressive evolution of the Andean fold-thrust belt. Spatial variations in transition zone characteristics indicate the foreland basin's central and southern sectors were fed by different sources and probably record separate fans. At Bahía Brookes, on Tierra del Fuego, foreland basin sedimentation began at least after 88-89 Ma, and possibly after ˜85 Ma, several million years after it did ˜700 km away at the northern end of the basin. This event coincided with increased arc volcanism and the partial obduction of the basaltic Rocas Verdes basin floor onto continental crust. By 81-80 Ma, conglomerate deposition and increased compositional and provenance complexity, including the abundance of metamorphic lithic fragments, indicate that the obducted basaltic floor first became emergent and was eroding. The results suggest that the beginning of turbidite sedimentation in the Magallanes foreland basin and the progressive incorporation and exhumation of deeply buried rocks in the Andean fold-thrust belt, occurred later in southern Patagonia than in the north by a few million years.

  18. Deforestation and benthic indicators: how much vegetation cover is needed to sustain healthy Andean streams?

    Directory of Open Access Journals (Sweden)

    Carlos Iñiguez-Armijos

    Full Text Available Deforestation in the tropical Andes is affecting ecological conditions of streams, and determination of how much forest should be retained is a pressing task for conservation, restoration and management strategies. We calculated and analyzed eight benthic metrics (structural, compositional and water quality indices and a physical-chemical composite index with gradients of vegetation cover to assess the effects of deforestation on macroinvertebrate communities and water quality of 23 streams in southern Ecuadorian Andes. Using a geographical information system (GIS, we quantified vegetation cover at three spatial scales: the entire catchment, the riparian buffer of 30 m width extending the entire stream length, and the local scale defined for a stream reach of 100 m in length and similar buffer width. Macroinvertebrate and water quality metrics had the strongest relationships with vegetation cover at catchment and riparian scales, while vegetation cover did not show any association with the macroinvertebrate metrics at local scale. At catchment scale, the water quality metrics indicate that ecological condition of Andean streams is good when vegetation cover is over 70%. Further, macroinvertebrate community assemblages were more diverse and related in catchments largely covered by native vegetation (>70%. Our results suggest that retaining an important quantity of native vegetation cover within the catchments and a linkage between headwater and riparian forests help to maintain and improve stream biodiversity and water quality in Andean streams affected by deforestation. This research proposes that a strong regulation focused to the management of riparian buffers can be successful when decision making is addressed to conservation/restoration of Andean catchments.

  19. Analysis of the drought resilience of Andosols on southern Ecuadorian Andean páramos

    Directory of Open Access Journals (Sweden)

    V. Iñiguez

    2015-11-01

    Full Text Available The neotropical Andean grasslands above 3500 m a.s.l. known as "páramo" offer remarkable ecological services for the Andean region. Most important is the water supply – of excellent quality – to many cities and villages established in the lowlands of the inter-Andean valleys and to the coast. However, the páramo ecosystem is under constant and increased threat by human activities and climate change. In this paper we study the resilience of its soils for drought periods during the period 2007–2013. In addition, field measurements and hydrological conceptual modelling at the catchment-scale are comparing two contrasting catchments in the southern Ecuadorian Andes. Both were intensively monitored during two and a half years (2010–2012 in order to analyse the temporal variability of the soil moisture storage. A typical catchment on the páramo at 3500 m a.s.l. was compared to a lower grassland one at 2600 m a.s.l. The main aim was to estimate the resilience capacity of the soils during a drought period and the recovery during a subsequent wet period. Local soil water content measurements in the top soil (first 30 cm through TDR were used as a proxy for the catchment's average soil moisture storage. The local measurements were compared to the average soil water storage as estimated by the probabilistic soil moisture (PDM model. This conceptual hydrological model with 5 parameters was calibrated and validated for both catchments. The study reveals the extraordinary resilience capacity of this type of shallow organic soils during the droughts in 2009 and 2010. During these droughts, the soil water content dropped from a normal value of about 0.80 to ~ 0.60 cm3 cm−3, while the recovery time was only two to three months.

  20. Identifying positive selection candidate loci for high-altitude adaptation in Andean populations

    Directory of Open Access Journals (Sweden)

    Bigham Abigail W

    2009-12-01

    Full Text Available Abstract High-altitude environments (>2,500 m provide scientists with a natural laboratory to study the physiological and genetic effects of low ambient oxygen tension on human populations. One approach to understanding how life at high altitude has affected human metabolism is to survey genome-wide datasets for signatures of natural selection. In this work, we report on a study to identify selection-nominated candidate genes involved in adaptation to hypoxia in one highland group, Andeans from the South American Altiplano. We analysed dense microarray genotype data using four test statistics that detect departures from neutrality. Using a candidate gene, single nucleotide polymorphism-based approach, we identified genes exhibiting preliminary evidence of recent genetic adaptation in this population. These included genes that are part of the hypoxia-inducible transcription factor (HIF pathway, a biochemical pathway involved in oxygen homeostasis, as well as three other genomic regions previously not known to be associated with high-altitude phenotypes. In addition to identifying selection-nominated candidate genes, we also tested whether the HIF pathway shows evidence of natural selection. Our results indicate that the genes of this biochemical pathway as a group show no evidence of having evolved in response to hypoxia in Andeans. Results from particular HIF-targeted genes, however, suggest that genes in this pathway could play a role in Andean adaptation to high altitude, even if the pathway as a whole does not show higher relative rates of evolution. These data suggest a genetic role in high-altitude adaptation and provide a basis for genotype/phenotype association studies that are necessary to confirm the role of putative natural selection candidate genes and gene regions in adaptation to altitude.

  1. Analysis of the drought resilience of Andosols on southern Ecuadorian Andean páramos

    Science.gov (United States)

    Iñiguez, V.; Morales, O.; Cisneros, F.; Bauwens, W.; Wyseure, G.

    2015-11-01

    The neotropical Andean grasslands above 3500 m a.s.l. known as "páramo" offer remarkable ecological services for the Andean region. Most important is the water supply - of excellent quality - to many cities and villages established in the lowlands of the inter-Andean valleys and to the coast. However, the páramo ecosystem is under constant and increased threat by human activities and climate change. In this paper we study the resilience of its soils for drought periods during the period 2007-2013. In addition, field measurements and hydrological conceptual modelling at the catchment-scale are comparing two contrasting catchments in the southern Ecuadorian Andes. Both were intensively monitored during two and a half years (2010-2012) in order to analyse the temporal variability of the soil moisture storage. A typical catchment on the páramo at 3500 m a.s.l. was compared to a lower grassland one at 2600 m a.s.l. The main aim was to estimate the resilience capacity of the soils during a drought period and the recovery during a subsequent wet period. Local soil water content measurements in the top soil (first 30 cm) through TDR were used as a proxy for the catchment's average soil moisture storage. The local measurements were compared to the average soil water storage as estimated by the probabilistic soil moisture (PDM) model. This conceptual hydrological model with 5 parameters was calibrated and validated for both catchments. The study reveals the extraordinary resilience capacity of this type of shallow organic soils during the droughts in 2009 and 2010. During these droughts, the soil water content dropped from a normal value of about 0.80 to ~ 0.60 cm3 cm-3, while the recovery time was only two to three months.

  2. The electronic contract formation in the framework of the Andean Community

    Directory of Open Access Journals (Sweden)

    William David Hernández

    2012-12-01

    Full Text Available The influence of the Information and Communication Technology (ICT in all the aspects of the society is an unquestionable fact that implies, for the Law, the inescapable responsibility of fostering the fulfillment of the declarations or objectives of the Society of Information. Today´s world, framed in a process of globalization and regional integration, heads to the normative harmonization. In line with the above, the present document studies the elements supporting the normative unification concerning the formation of the contract by electronic means in the Andean Community.

  3. Physics in the Andean Countries: A Perspective from Condensed Matter, Novel Materials and Nanotechnology

    Science.gov (United States)

    Prieto, P.

    2009-05-01

    We will discuss the current state of R&D in the fields of condensed matter, novel materials, and nanotechnology in the Andean nations. We will initially consider Latin America and the Caribbean (LAC) to then visualize individual developments, as well as those for the region as a whole in these fields of knowledge in each of the nations constituting the Andean Region (Bolivia, Ecuador, Chile, Venezuela, Peru, and Colombia). Based on Science & Technology watch exercises in the countries involved, along with the Iberian American and Inter-American Science & Technology Network of Indicators (Red de indicadores de Ciencia y Tecnolog'ia (RICYT) iberoamericana e interamericana)1, we will reveal statistical data that will shed light on the development in the fields mentioned. As will be noted, total R&D investment in Latin American and Caribbean countries remained constant since 1997. In spite of having reached a general increase in publications without international collaboration in LAC nations, the countries with greatest research productivity in Latin America (Argentina, Mexico, Brazil, and Chile) have strengthened their international collaboration with the United States, France, Germany, and Italy through close links associated with the formation processes of their researchers. Academic and research integration is evaluated through joint authorship of scientific articles, evidencing close collaboration in fields of research. This principle has been used in the creation of cooperation networks among participating nations. As far as networks of research on condensed matter, novel materials, and nanotechnology, the Andean nations have not consolidated a regional network allowing permanent and effective cooperation in research and technological development; as would be expected, given their idiomatic and cultural similarities, their historical background, and geographical proximity, which have been integrating factors in other research areas or socio-economic aspects. This

  4. Extensional Basins in a Convergent Margin: Oligocene-Early Miocene Salar de Atacama and Calama basins, Central Andes

    Science.gov (United States)

    Jordan, T. E.; Mpodozis, C.; Blanco, N.; Pananont, P.; Dávila, F.

    2004-12-01

    The Salar de Atacama Basin (SdAB) is the largest and most persistent sedimentary basin of northern Chile, accumulating nonmarine sediment from Cretaceous to modern times. Its northwestern neighbor, the Calama, was a Cenozoic basin. Although SdAB was in the backarc zone early in the Andean orogeny, both are now forearc basins. Others demonstrated that the basins overlie anomalously cold, strong, and dense crust and lithosphere. We focus on an extensional Oligocene basin stage. Interpretation of the basin-controlling faults is based on seismic reflection studies supported by field relations. The SdAB is limited to the west by the NNE-trending, steeply east-dipping, Paciencia Fault (PF). The PF experienced 5-7 km of down-to-the-east offset during the Oligocene-early Miocene. Syntectonic strata, an arid succession of siliciclastics and evaporites, are asymmetric, with thicknesses of 5000 m and abundant halite adjacent to the PF, and of 1000 m with fine detrital clastic strata 25 km farther east. Relations in conglomeratic growth strata that overlap the PF also demonstrate normal displacement during sediment accumulation. Seismic data reveal that a buried normal fault with 1-1.5 km down-to-the-east displacement limits the western margin of the Oligocene-Miocene Calama siliciclastic basin fill. Regionally, Oligocene-early Miocene margin-parallel strike-slip deformation dominated northwest of the basins, contributing sinistral offset (West Fissure Fault) to the northern segment of the long-lived Domeyko Fault System. The new SdAB and Calama data reveal that a 20,000 km2 domain of extensional basins existed within the dominantly strike-slip region. Even if PF and the fault in the Calama Basin were transtensional, the proportion of extension to strike-slip displacement is much greater in these basins than elsewhere in northern Chile. Further study is required to understand what combination of factors caused this kinematic distinction as well as delayed the onset of CVZ

  5. Using 10Be cosmogenic surface exposure dating to determine the evolution of the Purgatorio active fault in the Andean forearc, southern Peru

    Science.gov (United States)

    Carlos, Benavente; Swann, Zerathe; Laurence, Audin; Fabrizio, Delgado; Marianne, Saillard; Sarah, Hall R.; Aster Team

    2015-04-01

    Active transpressive deformation has been occurring along the Andean hyperarid forearc for the last 3 Myrs but many of these faults are still not described even if able to produce large damaging earthquakes. Active faulting along the northern part of the Arica Bend can be recognized due to the presence of well-preserved and sharp fault scarps indicating recent surface slip. During the Mio-Pliocene, deposition within the forearc continental basins resulted in the formation of vast fan deposits and conglomerates of the Moquegua Formation, which can be considered as bedrock in this exposure study (~45-4 Ma; Tosdal et al., 1984; Sebrier et al., 1988a; Roperch et al., 2006). The typical vertical Purgatorio fault scarps offset both the Moquegua bedrock and several younger geomorphic features associated with formation outcroping vertically along the fault scarp. These samples are well-suited to the application of in situ produced cosmogenic radionuclides for surface exposure dating, as the hyperarid region has extremely low erosion rates. We sampled the scarp away from any significant drainage so as to avoid possibly disturbed areas. The sampling did involve extracting quarzite conglomeratic material along the bedrock scarp and on the upper surrounding crests. The aim has been to measure Berylium-20 TCN (Terrestrial in situ Cosmogenic Nuclides) concentrations to determine exposure age as a function of height on the scarp. This has been successfully employed on one scarp in Italy based on Chlorine-36 TCN (Palumbo et al., 2004). However, slow faults behaviour remains unclear and more contributions are needed. Quaternary activity of the Purgatorio fault system was evidenced by Hall et al. (2008). They highlighted a vertical offset of about ~100 m for a pediment surface intercepted by the fault, and dated at ~280 ka. Considering that the pediment surface is horizontal, this would gave a maximum of ~0.3 mm/yr of vertical deformation since 280 ka. Our new data provide evidences

  6. Identification of aquifer limits inside an Andean Piedmont (between 19,5°S and 20°S - Northern Chile) with TDEM and gauging methods.

    Science.gov (United States)

    Viguier, Benoit; Jourde, Hervé; Leonardi, Véronique; Moya, Claudio; Líra, Elias; Yáñez, Gonzalo; Maringue, José; García-Pérez, Tiaren; Lictevout, Elisabeth

    2016-04-01

    In times of brutal climate changes and water scarcity in arid areas, the management of water resource has become a major issue. In this aim, several studies attempted to quantify the aquifer recharge and hydrodynamic processes. However, the quality of many studies depends on the characterization of aquifer boundaries. In arid areas, the amount of observation points (e.g. wells) and their spatial distribution constrain the understanding of aquifer boundaries spatial variations. In this study, we propose a methodology to characterize both water table level and boundaries of aquifer in such areas where the observation points do not exist. The Andean Piedmont (between 19,5°S and 20°S - Northern Chile) is located in the Pampa del Tamarugal Central Depression and is bounded respectively at the westside and the eastside by the Coastal Cordillera (1100 m a.s.l) and the Precordillera mountain range (4500 m a.s.l). The piedmont and the basin floor are composed of the late-Cenozoic alluvial deposits (hundred meters thick) which contain the Pampa del Tamarugal aquifer. Due to the hyperarid context, this regional aquifer is one of the main strategic groundwater resources in Northern Chile. This aquifer is mainly unconfined and the electrical conductivity of groundwater varies around 3000 μS/cm in the study area. The analysis of resistivity variation with depth, acquired by Time Domain Electromagnetic (TDEM) method in various points inside the piedmont, allow identifying a continuous resistivity contrast (from ≥ 100-40 Ω.m to ≤ 10 Ω.m) that varies over the study area. This continuous resistivity contrast is assumed to be related to the water table of the unconfined aquifer rather than to a lithology contrast. After validation of the observations, a piezometric map was constructed using both the available hydrogeological information and the TDEM results. In the piedmont, river sink were identified; these zones where surface water sinks are correlated with the resistivity

  7. Microseismic reflection imaging of the Central Andean crust

    Science.gov (United States)

    Schmelzbach, C.; Kummerow, J.; Wigger, P.; Reshetnikov, A.; Salazar, P.; Shapiro, S. A.

    2016-02-01

    The coda of passive seismic recordings is often rich in arrivals that are coherent across several stations. If reflections can be extracted, then they may be used for seismic reflection subsurface imaging. With the objective to image the upper crust of the North Chilean Precordillera (Central Andes; approximate location 21°S 69°W), we developed a workflow to process passive seismic data into subsurface reflection images. We analysed the waveform recordings of several hundred microseismic events using signal processing and imaging techniques adapted from active (controlled source) seismic imaging as used in the oil industry. Key processing steps involved precise arrival time picking and hypocentre determination, removing signal amplitude variations due to varying source radiation patterns, identification and separation of reflections from coherent noise, and transformation of the processed waveforms into images of the subsurface reflectivity. When designing our microseismic reflection imaging workflow, we took advantage of the fact that the passive seismic recording geometry with the hypocentres located at depth and the receivers positioned at the surface resembles a reverse vertical-seismic profiling experiment. The resultant P- and S-wave reflection images reveal several reflective features, such as an approximate 15° westward dipping reflector over the 5-25 km depth range that largely coincides with a distinct seismicity boundary. We interpret the imaged interface as the brittle-ductile transition zone boundary, possibly enhanced by a tectonic shear zone. For the area of the North Chilean Precordillera, the deduced microseismic reflection sections with horizontal extensions of about 50 km represent the first high-resolution images of the shallow crust, which could not be obtained from previous active-source seismic-reflection data.

  8. Backarc basin evolution and cordilleran orogenesis: Insights from new ocean-bottom seismograph refraction profiling in Bransfield Strait, Antarctica

    Science.gov (United States)

    Barker, Daniel H. N.; Christeson, Gail L.; Austin, James A., Jr.; Dalziel, Ian W. D.

    2003-02-01

    Bransfield Strait, a backarc basin off the northwestern Antarctic Peninsula, is a modern analog for Cretaceous basins inverted in the compressional tectonic regime that initiated the Andean Cordillera. Eight new refraction ocean-bottom seismograph profiles in the strait demonstrate that crustal thickness in the deep central basin increases from northeast to southwest, from ˜10 km to ˜14 16 km. This confirms multichannel seismic interpretation of upper crustal structures suggesting that the Bransfield basin is opening by northeast to southwest rift propagation within arc crust of the Antarctic Peninsula, a process also recorded in the obducted Cretaceous Rocas Verdes basin of the southernmost Andes. Thinning is most prominent along the axis of the strait, where the crust is ˜9 11 km thick. In contrast, thicknesses beneath the Antarctic Peninsula margin and the inactive South Shetland Islands pedestal are ˜18 km and ˜24 km, respectively. Seismic velocities and thicknesses suggest that new oceanic crust is not yet being generated. Extension is focused along the northwest margin, imparting the physiographic asymmetry to the strait. Comparing the Bransfield basin with the inverted Rocas Verdes basin and intraoceanic counterparts in the western Pacific suggests that rift propagation and trench-side focusing of extension may be fundamental features of young backarc basins. Resultant asymmetry may facilitate observed obduction of backarc basin floor and arc rocks onto continental margins during compressional orogenesis.

  9. Variability in warm-season atmospheric circulation and precipitation patterns over subtropical South America: relationships between the South Atlantic convergence zone and large-scale organized convection over the La Plata basin

    Science.gov (United States)

    Mattingly, Kyle S.; Mote, Thomas L.

    2016-03-01

    Warm-season precipitation variability over subtropical South America is characterized by an inverse relationship between the South Atlantic convergence zone (SACZ) and precipitation over the central and western La Plata basin of southeastern South America. This study extends the analysis of this "South American Seesaw" precipitation dipole to relationships between the SACZ and large, long-lived mesoscale convective systems (LLCSs) over the La Plata basin. By classifying SACZ events into distinct continental and oceanic categories and building a logistic regression model that relates LLCS activity across the region to continental and oceanic SACZ precipitation, a detailed account of spatial variability in the out-of-phase coupling between the SACZ and large-scale organized convection over the La Plata basin is provided. Enhanced precipitation in the continental SACZ is found to result in increased LLCS activity over northern, northeastern, and western sections of the La Plata basin, in association with poleward atmospheric moisture flux from the Amazon basin toward these regions, and a decrease in the probability of LLCS occurrence over the southeastern La Plata basin. Increased oceanic SACZ precipitation, however, was strongly related to reduced atmospheric moisture and decreased probability of LLCS occurrence over nearly the entire La Plata basin. These results suggest that continental SACZ activity and large-scale organized convection over the northern and eastern sections of the La Plata basin are closely tied to atmospheric moisture transport from the Amazon basin, while the warm coastal Brazil Current may also play an important role as an evaporative moisture source for LLCSs over the central and western La Plata basin.

  10. Analysis on the hydrogeological condition and uranium mineralization prospect in Santanghu basin, Xinjiang

    International Nuclear Information System (INIS)

    Santanghu basin is an infiltration depression basin with forward direction hydrogeological and hydrogeochemical zonation. The basin has a well developed aquifer and favorable mud-sand-mud pattern and abundant uranium source. The distribution pattern of uranium in the ground water is favorable for the precipitation and enrichment of uranium in transitional part of redox zone. (authors)

  11. 快速城镇化进程中湘江流域生态脆弱性格局及驱动机理%Patterns and Driving Factors of Ecological Vulnerability of the Xiangjiang River Basin in Rapid Urbanization

    Institute of Scientific and Technical Information of China (English)

    向云波; 彭秀芬; 谢炳庚; 杨沙

    2014-01-01

    从自然成因与结果表现两方面,选取8个单项指标,构建湘江流域生态脆弱性评价指标体系。采用遥感和社会经济统计数据,运用主成分分析法,结合 GIS 技术,研究2000~2010年湘江流域生态脆弱性时空特征,并对其生态脆弱性进行空间自相关分析。研究结果表明:(1)2000~2010年湘江流域生态脆弱性程度有小幅下降,流域生态脆弱性均值由0.4468下降至0.4181。(2)将流域生态脆弱性划分为5个基本类型,2000~2010年间湘江流域极强脆弱、强度脆弱类型区栅格数量比重分别下降了2.04%和13.47%,中度脆弱、轻度脆弱和微度脆弱类型区栅格数量分别增加了1.13%、3.01%和4.45%。(3)湘江流域生态脆弱性空间差异显著,具有集簇分布的特征。生态脆弱区的空间聚集程度呈现出较高的正相关,空间格局伴有破碎化的发展趋势。生态脆弱性显著性相关区域主要分布在长株潭、娄底、永州市辖区;低相关区域主要分布在罗霄山、南岭地区。%The author of this article constructs an evaluation indicator system of ecological vulnerability based on the causes and consequences of natural features .This paper studies the evolution patterns and spatial autocorrelation analysis of ecosystem vulnerability in the Xiangjiang Basin using the method of principal component analysis ,combined with GIS technology from 2000 to 2010 .The results show that :(1) The ecological vulnerability steady declined in Xiangjiang river basin from 2000 to 2010 . The mean value of ecological vulnerability declined from 0.4468 to 0.4181 .The rate of the extremely strong and strong ecological vulnerability area decreased 2.04% and 13.47% . The rate of moderately vulnerable ,weak vulnerable and micro vulnerable types of area increased respectively 1.13% ,3.01% and 4.45% . (2) The ecological vulnerability has obvious regional difference and spatial

  12. Coupling age-structured stock assessment and fish bioenergetics models: a system of time-varying models for quantifying piscivory patterns during the rapid trophic shift in the main basin of Lake Huron

    Science.gov (United States)

    He, Ji X.; Bence, James R.; Madenjian, Charles P.; Pothoven, Steven A.; Dobiesz, Norine E.; Fielder, David G.; Johnson, James E.; Ebener, Mark P.; Cottrill, Adam R.; Mohr, Lloyd C.; Koproski, Scott R.

    2015-01-01

    We quantified piscivory patterns in the main basin of Lake Huron during 1984–2010 and found that the biomass transfer from prey fish to piscivores remained consistently high despite the rapid major trophic shift in the food webs. We coupled age-structured stock assessment models and fish bioenergetics models for lake trout (Salvelinus namaycush), Chinook salmon (Oncorhynchus tshawytscha), walleye (Sander vitreus), and lake whitefish (Coregonus clupeaformis). The model system also included time-varying parameters or variables of growth, length–mass relations, maturity schedules, energy density, and diets. These time-varying models reflected the dynamic connections that a fish cohort responded to year-to-year ecosystem changes at different ages and body sizes. We found that the ratio of annual predation by lake trout, Chinook salmon, and walleye combined with the biomass indices of age-1 and older alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) increased more than tenfold during 1987–2010, and such increases in predation pressure were structured by relatively stable biomass of the three piscivores and stepwise declines in the biomass of alewives and rainbow smelt. The piscivore stability was supported by the use of alternative energy pathways and changes in relative composition of the three piscivores. In addition, lake whitefish became a new piscivore by feeding on round goby (Neogobius melanostomus). Their total fish consumption rivaled that of the other piscivores combined, although fish were still a modest proportion of their diet. Overall, the use of alternative energy pathways by piscivores allowed the increases in predation pressure on dominant diet species.

  13. Stable water isotope variation in a Central Andean watershed dominated by glacier and snowmelt

    Directory of Open Access Journals (Sweden)

    N. Ohlanders

    2013-03-01

    Full Text Available Central Chile is an economically important region for which water supply is dependent on snow- and ice melt. Nevertheless, the relative contribution of water supplied by each of those two sources remains largely unknown. This study represents the first attempt to estimate the region's water balance using stable isotopes of water in streamflow and its sources. Isotopic ratios of both H and O were monitored during one year in a high-altitude basin with a moderate glacier cover (11.5%. We found that the steep altitude gradient of the studied catchment caused a corresponding gradient in snowpack isotopic composition and that this spatial variation had a profound effect on the temporal evolution of streamflow isotopic composition during snowmelt. Glacier melt and snowmelt contributions to streamflow in the studied basin were determined using a quantitative analysis of the isotopic composition of streamflow and its sources, resulting in a glacier melt contribution of 50–90% for the unusually dry melt year of 2011/2012. This suggests that in (La Niña years with little precipitation, glacier melt is an important water source for central Chile. Predicted decreases in glacier melt due to global warming may therefore have a negative long-term impact on water availability in the Central Andes. The pronounced seasonal pattern in streamflow isotope composition and its close relation to the variability in snow cover and discharge presents a potentially powerful tool to relate discharge variability in mountainous, melt-dominated catchments with related factors such as contributions of sources to streamflow and snowmelt transit times.

  14. Stable water isotope variation in a Central Andean watershed dominated by glacier- and snowmelt

    Directory of Open Access Journals (Sweden)

    N. Ohlanders

    2012-10-01

    Full Text Available Central Chile is an economically important region for which water supply is dependent on snow- and ice melt. Nevertheless, the fraction of water supplied by each of those two sources remains largely unknown. This study represents the first attempt to estimate the region's water balance using stable isotopes of water in streamflow and its sources; isotopic ratios of both H and O were monitored during one year in a high-altitude basin with a relatively high glacial cover (11.5%. We found that the steep altitude gradient of the studied catchment caused a corresponding gradient in snowpack isotopic composition and that this spatial variation had a profound effect on the temporal evolution of streamflow isotopic composition during snowmelt. Glacier- and snowmelt contributions to streamflow in the studied basin were calculated using a quantitative analysis of the isotopic composition of streamflow and its sources, resulting in a glacier melt contribution of 50–80% for the unusually dry melt year of 2011/12. This suggests that in (la Niña years with little precipitation, glacier melt is an important water source for Central Chile. Predicted decreases in glacier melt due to global warming may therefore have a negative impact on water availability in the Central Andes as well as in comparable semi-arid regions of the world; this impact is non-commensurable with areal glacial cover or with the relative areal influence coverage of glacier versus seasonal snowpack. The pronounced seasonal pattern in streamflow isotope composition and its close relation to the evolution of snow cover and to discharge presents a potentially powerful tool for relating discharge evolution in mountainous, melt-dominated catchments with related factors such as contributions of sources to streamflow and snowmelt transit times.

  15. Fossil pollen records indicate that Patagonian desertification was not solely a consequence of Andean uplift

    Science.gov (United States)

    Palazzesi, L.; Barreda, V. D.; Cuitiño, J. I.; Guler, M. V.; Tellería, M. C.; Ventura Santos, R.

    2014-03-01

    The Patagonian steppe—a massive rain-shadow on the lee side of the southern Andes—is assumed to have evolved ~15-12 Myr as a consequence of the southern Andean uplift. However, fossil evidence supporting this assumption is limited. Here we quantitatively estimate climatic conditions and plant richness for the interval ~10-6 Myr based on the study and bioclimatic analysis of terrestrially derived spore-pollen assemblages preserved in well-constrained Patagonian marine deposits. Our analyses indicate a mesothermal climate, with mean temperatures of the coldest quarter between 11.4 °C and 16.9 °C (presently ~3.5 °C) and annual precipitation rarely below 661 mm (presently ~200 mm). Rarefied richness reveals a significantly more diverse flora during the late Miocene than today at the same latitude but comparable with that approximately 2,000 km further northeast at mid-latitudes on the Brazilian coast. We infer that the Patagonian desertification was not solely a consequence of the Andean uplift as previously insinuated.

  16. Projected distribution shifts and protected area coverage of range-restricted Andean birds under climate change

    Directory of Open Access Journals (Sweden)

    Verónica del Rosario Avalos

    2015-07-01

    Full Text Available In this study we projected the effect of anthropogenic climate change in endemic and restricted-range Andean bird species that spread out from the center of Bolivia to southeastern Peru. We also analyzed the representation of these species in protected areas. The ensemble forecasts from niche-based models indicated that 91–100% of species may reduce their range size under full and no dispersal scenarios, including five species that are currently threatened. The large range reduction (average 63% suggests these mountain species may be threatened by climate change. The strong effects due to range species losses are predicted in the humid mountain forests of Bolivia. The representation of bird species also decreased in protected areas. Partial gap species (94–86% are expected to increase over the present (62%. This suggests climate change and other non-climate stressors should be incorporated in conservations plans for the long-term persistence of these species. This study anticipates the magnitude of shifts in the distribution of endemic birds, and represents in the study area the first exploration of the representation of range-restricted Andean birds in protected areas under climate change.

  17. Molecular characterization of the Andean blackberry, Rubus glaucus, using SSR markers.

    Science.gov (United States)

    Marulanda, M; López, A M; Uribe, M

    2012-01-01

    The species Rubus glaucus, also known as the Andean or "Castilla" blackberry, is one of nine edible species of this genus that grow naturally in Central and South America. In Colombia, this species is the most important of all Rubus species for agricultural and commercial purposes. We used 20 SSRs developed for other Rubus species to characterize 44 Colombian R. glaucus genotypes, collected from eight different departments, and to look for molecular differences between thornless and thorny cultivated blackberries. Eighty-two bands were obtained from 28 loci. The genotypes were classified into eight populations, corresponding to collection sites. The mean number of polymorphic alleles per locus in all populations and genotypes ranged from 1.857 to 2.393. Samples collected from Valle del Cauca, Quindío, Caldas, and Risaralda departments had the highest heterozygosity values. The finding of exclusive bands from R. glaucus genotypes from Valle del Cauca, Quindío, and Caldas demonstrates genetic and molecular differentiation between thorny and thornless Andean blackberries. PMID:22370934

  18. Distribution of Aboveground Live Biomass in the Amazon Basin

    Science.gov (United States)

    Saatchi, S. S.; Houghton, R. A.; DosSantos Alvala, R. C.; Soares, J. V.; Yu, Y.

    2007-01-01

    The amount and spatial distribution of forest biomass in the Amazon basin is a major source of uncertainty in estimating the flux of carbon released from land-cover and land-use change. Direct measurements of aboveground live biomass (AGLB) are limited to small areas of forest inventory plots and site-specific allometric equations that cannot be readily generalized for the entire basin. Furthermore, there is no spaceborne remote sensing instrument that can measure tropical forest biomass directly. To determine the spatial distribution of forest biomass of the Amazon basin, we report a method based on remote sensing metrics representing various forest structural parameters and environmental variables, and more than 500 plot measurements of forest biomass distributed over the basin. A decision tree approach was used to develop the spatial distribution of AGLB for seven distinct biomass classes of lowland old-growth forests with more than 80% accuracy. AGLB for other vegetation types, such as the woody and herbaceous savanna and secondary forests, was directly estimated with a regression based on satellite data. Results show that AGLB is highest in Central Amazonia and in regions to the east and north, including the Guyanas. Biomass is generally above 300Mgha(sup 1) here except in areas of intense logging or open floodplains. In Western Amazonia, from the lowlands of Peru, Ecuador, and Colombia to the Andean mountains, biomass ranges from 150 to 300Mgha(sup 1). Most transitional and seasonal forests at the southern and northwestern edges of the basin have biomass ranging from 100 to 200Mgha(sup 1). The AGLB distribution has a significant correlation with the length of the dry season. We estimate that the total carbon in forest biomass of the Amazon basin, including the dead and below ground biomass, is 86 PgC with +/- 20% uncertainty.

  19. Phenolic compound contents and antioxidant activity in plants with nutritional and/or medicinal properties form the Peruvian Andean region

    NARCIS (Netherlands)

    Chirinos, R.; Pedreschi Plasencia, R.P.; Rogez, H.

    2013-01-01

    Total phenolic compounds (TPC) and antioxidant activities using different assays (DPPH, ABTS and ORAC) in fruits, grains, leaves, seeds, roots and tubers from 27 different Peruvian Andean plants used in folk medicine or/and as food by the native population were evaluated in order to use these as nat

  20. Contextual Analysis of the Decision To Adopt a Regional Satellite System: The Case of the Andean CONDOR.

    Science.gov (United States)

    Ferreira, Leonardo; Mody, Bella

    Acknowledging the importance of communications in economic development, this paper discusses the rationale behind the decision of the Andean Pact nations of Bolivia, Colombia, Ecuador, Peru, and Venezuela to develop a regional satellite communication system to be known as CONDOR. The application of contextual theorizing to the decision-making…

  1. Provenance of eastern Magallanes foreland basin sediments: Mineralogical and geochemical analyses reveal Paleogene tectonic unroofing of the Fuegian Andes

    Science.gov (United States)

    Zahid, Khandaker

    Though southern South America and the Antarctic Peninsula were previously connected through a Paleozoic-Mesozoic subduction system on the western margin of Gondwana, this connection was tectonically disrupted in the Cenozoic by forming the Drake Passage in the Scotia Sea. Heavy mineral composition data from the eastern Magallanes basin of southernmost South America indicate that Campanian to middle Eocene sediments had a mafic/ophiolitic provenance which is interpreted as being derived from the Patagonian-Fuegian magmatic arc and the mafic floor of the preceding Rocas Verdes marginal basin. Upper middle Eocene to lower Miocene heavy minerals, on the other hand, indicate a metamorphic/metasedimentary provenance, which suggest being derived from the Cordillera Darwin metamorphic complex. While the rare earth element patterns of all of these samples are typical to those of average post-Archean upper continental crustal types, the younger middle-upper Eocene and lower Oligocene samples contain a higher concentration of the light REEs (LaN/SmN) ratio compared to the older upper Cretaceous to middle Eocene samples suggesting an eastern Andean metamorphic complex provenance for younger sediments. Trace elements plot of stratigraphically older samples exhibit a lower Th/Sc ratio compared to the younger samples suggesting a mafic origin. Nd isotope data show a shift in epsilonNd values from a less negative to a more negative value also during the middle to late Eocene. Together, these data indicate an abrupt shift in sediment provenance in middle to late Eocene time, thereby corroborating recent interpretations of the basin's detrital-zircon geochrononology and thermochronology, and providing further support for temporal and possibly genetic relationships between development of the Patagonian orocline, the opening of Drake Passage and the Oi-1 glaciation of Antarctica. Quantifying the relative abundance of different framework mineral components of sandstone is a common

  2. EXTENSION OF SEQUENCE STRATIGRAPHIC MODEL AND SEQUENCE STRATIGRAPHC ANALYSIS IN LIMNIC DEPOSITIONAL BASIN

    Institute of Scientific and Technical Information of China (English)

    李增学; 魏久传; 王民镇; 李守春; 李青山; 金秀昆; 兰恒星

    1996-01-01

    The architectural patterns of sedimentary succession are diverse in different depositionalbasins. The sedimentary architecture and geological condition of such basins asepicontinental sea, intraplate limnic basins, etc., differ clearly from those of continentalmargin basin. Extension, complement and perfection of sequence stratigraphic models are needed in the studies ofvarious depositional basins based on the classical sequence model. This paper, for this reason,expounds the thought, principles of sequence division, methodology and technology of the studyof sequence stratigraphy in epicontinental and limnic basins.

  3. Analysis of the drought recovery of Andosols on southern Ecuadorian Andean páramos

    Science.gov (United States)

    Iñiguez, Vicente; Morales, Oscar; Cisneros, Felipe; Bauwens, Willy; Wyseure, Guido

    2016-06-01

    The Neotropical Andean grasslands above 3500 m a.s.l., known as páramo, offer remarkable ecological services for the Andean region. The most important of these is the water supply of excellent quality to many cities and villages in the inter-Andean valleys and along the coast. The páramo ecosystem and especially its soils are under constant and increased threat by human activities and climate change. In this study, the recovery speed of the páramo soils after drought periods are analysed. The observation period includes the droughts of 2009, 2010, 2011, and 2012 together with intermediate wet periods. Two experimental catchments - one with and one without páramo - were investigated. The Probability Distributed Moisture (PDM) model was calibrated and validated in both catchments. Drought periods and its characteristics were identified and quantified by a threshold level approach and complemented by means of a drought propagation analysis. At the plot scale in the páramo region, the soil water content measured by time domain reflectometry (TDR) probes dropped from a normal value of about 0.84 to ˜ 0.60 cm3 cm-3, while the recovery time was 2-3 months. This did not occur at lower altitudes (Cumbe) where the soils are mineral. Although the soil moisture depletion observed in these soils was similar to that of the Andosols (27 %), decreasing from a normal value of about 0.54 to ˜ 0.39 cm3 cm-3, the recovery was much slower and took about 8 months for the drought in 2010. At the catchment scale, however, the soil water storage simulated by the PDM model and the drought analysis was not as pronounced. Soil moisture droughts occurred mainly in the dry season in both catchments. The deficit for all cases is small and progressively reduced during the wet season. Vegetation stress periods correspond mainly to the months of September, October and November, which coincides with the dry season. The maximum number of consecutive dry days were reached during the drought of

  4. Integración regional andina en salud Health in Andean regional integration

    Directory of Open Access Journals (Sweden)

    Carlos A. Agudelo

    2007-01-01

    Full Text Available A pesar su historia compartida, los países de la Región Andina presentan una diversidad social y política que genera realidades sanitarias heterogéneas y procesos de integración complejos. Se han dado por décadas procesos generales, como la Asociación Latinoamericana de Libre Comercio y la Asociación Latinoamericana de Integración, o de alcance regional como la Comunidad Andina de Naciones, la Comunidad del Caribe y el Mercado Común Centroamericano. En el campo específico de la salud se cuenta con un instrumento en la Región Andina, el Convenio Hipólito Unánue, creado en 1971. Estos procesos de integración se han concentrado en los aspectos económicos, con base en acuerdos de preferencias arancelarias, los cuales han generado, en el largo plazo, un intercambio comercial apreciable. En el campo de la salud se ha avanzado menos, en términos de procesos que ponen en común experiencias nacionales, conocimientos y capacidades. El análisis de las experiencias de integración en salud muestra que esta depende de las fortalezas de cada país y, en gran parte, de los procesos políticos nacionales.Despite their shared history, the Andean countries are socially and politically diverse, with heterogeneous health realities and complex integration processes. General developments such as the Latin American Free Trade Association and Latin American Integration Association have existed for decades, along with others of a regional scope, like the Andean Community of Nations, Caribbean Community, and Central American Common Market. The health field has a specific instrument in the Andean Region called the Hipólito Unánue Agreement, created in 1971. Integration processes have concentrated on economic aspects, based on preferential customs agreements that have led to an important long-term increase in trade. Less progress has been made in the field of health in terms of sharing national experiences, knowledge, and capabilities. Analysis of

  5. Effect of human disturbance on seed and seedling distribution of the Andean Oak (Quercus humboldtii Bonpl., Fagaceae) in the Colombian Eastern Cordillera

    International Nuclear Information System (INIS)

    Animals affect the spatial occupation patterns of tropical forest plants throughout the seed dispersal they perform. Therefore, changes in vertebrate populations by human disturbance might affect re generation dynamics of plant species. We studied differences in the spatial distribution of seeds and seedlings of the Andean oak (Quercus humboldtii) between two nearby forests with contrasting levels of anthropogenic influence in the Colombian Andes. Density and spatial distribution of seedlings were evaluated in 490 and 484 1 m2 plots located in a 28 ha area, in the high and low disturbed site, respectively. In each plot, all seedlings found were sampled and classified into three age categories. Density and spatial distribution of seeds were evaluated in 0.25 m2subplots placed in the same plots described above. Results showed a higher number and density of seedlings in the high disturbed site, as well as a marked decrease in seedling density as age increases. Distances to the nearest neighbour were shorter in the high disturbed site for all seedlings and each age category, in contrast to the low disturbed site. Indexes of spatial distribution indicate an aggregated pattern in the most disturbed site, while a uniform pattern in the low disturbed one. Seeds also exhibited an aggregated pattern in the high disturbed site and a higher seed predation by invertebrates. Results seemed to be a consequence of forest fragmentation and a decrease of vertebrate seed dispersers, seed predators and herbivores associated to the regeneration processes of the species. These results provide important information for the forest management and restoration activities, since in order to maintain plant populations in the long term, presence and viable populations of seed dispersers should be also maintained.

  6. Basins of Attraction for Chimera States

    DEFF Research Database (Denmark)

    Martens, Erik Andreas; Panaggio, Mark; Abrams, Daniel

    2016-01-01

    Chimera states---curious symmetry-broken states in systems of identical coupled oscillators---typically occur only for certain initial conditions. Here we analyze their basins of attraction in a simple system comprised of two populations. Using perturbative analysis and numerical simulation we...... evaluate asymptotic states and associated destination maps, and demonstrate that basins form a complex twisting structure in phase space. Understanding the basins' precise nature may help in the development of control methods to switch between chimera patterns, with possible technological and neural system...

  7. History aspects and ecology of the biodiversity nor Andean and Amazonic

    International Nuclear Information System (INIS)

    The mega-biodiversity of the neotropics is type result of the geological and environmental history. A considerable biodiversity, higher than at present, existed in the Miocene in the low-elevation tropics. The progressive upheaval of the Andes created new life zones that were populated by adaptive evolution and immigration from the austral-Antarctic and laurasiatic-holartic regions. The cooling of the earth during the Neogene and the glacial- interglacial cycles of the quaternary, and the consonant changes of temperature and rainfall, in combination with the topography, had a profound effect on vegetation, flora and fauna, the distribution of species and endemism, both in the low tropical area and in the Andean zones. Presently there is a positive relation of species-density with temperature (altitude) and with rainfall, and partly with relative humidity

  8. The CERESIS earthquake catalogue and database of the Andean Region: background, characteristics and examples of use

    Directory of Open Access Journals (Sweden)

    L. R. Valverde

    2004-06-01

    Full Text Available The history of earthquakes in South America starts with the coming of the Spanish and Portuguese «conquistadores» at the beginning of the 16th century. Their chronicles, and those of local historians, are the only source of earthquake information for the following 400 years. The creation of the Regional Centre for Seismology for South America (CERESIS was a major factor for homogenous regional progress, in that CERESIS promoted the implementation of the first unified earthquake catalogue and database for the whole Andean Region. This paper reviews basic information about the intensity database and the focal parameter catalogues proposed by CERESIS in 1985. Further macroseismic data available from the CERESIS database (earthquakes with I0 = 8 are used to obtain preliminary results for the earthquake source parameters of selected South American historical events. The case of the Great Earthquake of the Venezuelan Andes, 29 April 1894, is presented in some detail.

  9. Feeding Ecology of Two Plecopterans in Low Order Andean-Patagonian Streams

    Science.gov (United States)

    Albariño, Ricardo J.; Díaz Villanueva, Verónica

    2006-05-01

    Feeding plasticity of the Andean plecopteran Klapopteryx kuscheli and Notoperla archiplatae larvae was assessed through a field experiment using enclosures. K. kuscheli has previously been described as a shredder and N. archiplatae as a scraper. Further information on gut contents from different populations supported those results. In the experiment, larvae of both species were exposed to contrasting food items: leaf litter and periphyton. Consumption, growth and the efficiency of food conversion were measured. K. kuscheli was able to feed on periphyton, though it did not grow. N. archiplatae failed to feed on leaf litter. While K. kuscheli might be considered a facultative shredder, N. archiplatae functions as a specialist scraper. The natural distribution and seasonal abundance in two small streams showed contrasting habitat use of both species. N. archiplatae inhabited high velocity runs and riffles underneath large substrates while K. kuscheli presented a higher habitat plasticity. Implications of those results for ecosystem function are discussed.

  10. Spatial modeling of cutaneous leishmaniasis in the Andean region of Colombia.

    Science.gov (United States)

    Pérez-Flórez, Mauricio; Ocampo, Clara Beatriz; Valderrama-Ardila, Carlos; Alexander, Neal

    2016-06-27

    The objective of this research was to identify environmental risk factors for cutaneous leishmaniasis (CL) in Colombia and map high-risk municipalities. The study area was the Colombian Andean region, comprising 715 rural and urban municipalities. We used 10 years of CL surveillance: 2000-2009. We used spatial-temporal analysis - conditional autoregressive Poisson random effects modelling - in a Bayesian framework to model the dependence of municipality-level incidence on land use, climate, elevation and population density. Bivariable spatial analysis identified rainforests, forests and secondary vegetation, temperature, and annual precipitation as positively associated with CL incidence. By contrast, livestock agroecosystems and temperature seasonality were negatively associated. Multivariable analysis identified land use - rainforests and agro-livestock - and climate - temperature, rainfall and temperature seasonality - as best predictors of CL. We conclude that climate and land use can be used to identify areas at high risk of CL and that this approach is potentially applicable elsewhere in Latin America. PMID:27355214

  11. Fruit mineral contents of six wild species of the North Andean Patagonia, Argentina.

    Science.gov (United States)

    Damascos, María A; Arribere, Maria; Svriz, Maya; Bran, Donaldo

    2008-10-01

    The fruit mineral contents (K, Ca, Ba, Br, Zn, Co, Cr, Fe, Na, Rb, Cs, and Sr) of four native and two exotic naturalized shrubs growing in different areas of the Andean Patagonian region of Argentina were investigated. Native species Berberis darwinii, Berberis microphylla (Berberidaceae), Aristotelia chilensis (Elaeocarpaceae) and Ribes magellanicum (Saxifragaceae) produce small berries while the fruits of the exotic species Rosa rubiginosa and Rosa canina (Rosaceae) are aggregates of aquenes. They are used to prepare jams, tea, liquors, and ice creams. Native shrub fruits had higher content of Br, Zn, Co, Cr, Fe, Mo, and Na than those of the exotic naturalized species. Rosa species showed the highest contents of Ca and Ba in their fruits (the mean content doubled those of the native plant fruits). The fruit nutrient content found in the studied species was similar or higher than other values reported for fruits of temperate and tropical species in the world. PMID:18512032

  12. Traditional use of the Andean flicker (Colaptes rupicola as a galactagogue in the Peruvian Andes

    Directory of Open Access Journals (Sweden)

    Froemming Steve

    2006-05-01

    Full Text Available Abstract This paper explores the use of the dried meat and feathers of the Andean Flicker (Colaptes rupicola to increase the milk supply of nursing women and domestic animals in the Andes. The treatment is of preColumbian origin, but continues to be used in some areas, including the village in the southern Peruvian highlands where I do ethnographic research. I explore the factors giving rise to and sustaining the practice, relate it to other galactagogues used in the Andes and to the use of birds in ethnomedical and ethnoveterinary treatments in general, and situate it within the general tendency in the Andes and elsewhere to replicate human relations in the treatment of valuable livestock. The bird's use as a galactagogue appears to be motivated by both metaphorical associations and its perceived efficacy, and conceptually blends human and animal healthcare domains.

  13. Invertebrate metacommunity structure and dynamics in an andean glacial stream network facing climate change

    DEFF Research Database (Denmark)

    Cauvy-Fraunié, Sophie; Espinosa, Rodrigo; Andino, Patricio;

    2015-01-01

    Under the ongoing climate change, understanding the mechanisms structuring the spatial distribution of aquatic species in glacial stream networks is of critical importance to predict the response of aquatic biodiversity in the face of glacier melting. In this study, we propose to use metacommunity...... theory as a conceptual framework to better understand how river network structure influences the spatial organization of aquatic communities in glacierized catchments. At 51 stream sites in an Andean glacierized catchment (Ecuador), we sampled benthic macroinvertebrates, measured physico.......g., overland, watercourse, and downstream directional dispersal) in organizing the aquatic metacommunity. Results revealed that both environmental and spatial variables significantly explained community variation among sites. Among all environmental variables, the glacial influence component best explained...

  14. An Environmental Watch System for the Andean countries: El Observatorio Andino

    CERN Document Server

    Muñoz, Ángel G; Velasquez, Ramon; Monterrey, Luis; Leon, Gloria; Ruiz, Franklyn; Recalde, Cristina; Cadena, Jaime; Mejia, Raul; Paredes, Marcos; Bazo, Juan; Reyes, Carmen; Carrasco, Gualberto; Castellon, Yaruska; Villarroel, Claudia; Quintana, Juan; Urdaneta, Avel

    2010-01-01

    An experimental Environmental Watch System, the so-called Observatorio Andino-OA (Observatorio Andino), has been implemented in Venezuela, Colombia, Ecuador, Peru, Bolivia, and Chile over the past two years. The OA is a collaborative and regional network that aims to monitor several environmental variables and develop accurate forecasts based on different scientific tools. Its overall goal is to improve risk assessments, set up Early Warning Systems, support decision-making processes, and provide easily- and intuitively-understandable spatial maps to end-users. The initiative works under the scientific and logistic coordination of the Centro de Modelado Cient\\'ifico (CMC) at Zulia University, Venezuela, and the Centro Internacional para la Investigaci\\'on del Fen\\'omeno 'El Ni\\~no' (CIIFEN), and is operated at a local level by the National Weather Services (NWSs) of the aforementioned six Andean nations. The OA provides several freely-available model outputs including meteorological and hydrological forecasts...

  15. How do subduction processes contribute to forearc Andean uplift? Insights from numerical models

    Science.gov (United States)

    Martinod, J.; Regard, V.; Letourmy, Y.; Henry, H.; Hassani, R.; Baratchart, S.; Carretier, S.

    2016-05-01

    We present numerical models to study how changes in the process of subduction may explain the observed Quaternary uplift of the Andean forearc region. Indeed, most segments of the South American Pacific coasts between 16 and 32° S have been uplifting since the Lower Pleistocene, following a period of stability of the forearc region. Models confirm that local uplift is expected to occur above ridges, this phenomenon being predominant in central Peru where the Nazca Ridge is subducting. We investigate the effects of slab pull, interplate friction and convergence velocity on the vertical displacements of the overriding plate. We propose that the global tendency to coastal uplift is accompanying the deceleration of the Nazca-South America convergence that occurred in the Pleistocene. In contrast, forearc subsidence may accompany increasing convergence velocities, as suggested by the subsidence history of the South America active margin.

  16. The Sabethines of Northern Andean Coffee-Growing Regions of Colombia.

    Science.gov (United States)

    Suaza-Vasco, Juan; López-Rubio, Andrés; Galeano, Juan; Uribe, Sandra; Vélez, Iván; Porter, Charles

    2015-06-01

    Sampling for sabethine mosquitoes occurred intermittently from September 2007 to April 2013 in 17 municipalities, located in 5 departments (divisions) in the northern Andean coffee-growing regions of Colombia. Of the 9 genera within the Sabethini tribe known to occur in the Neotropical region, 6 were encountered including 15 species: Jonhbelkinia ulopus, Limatus durhamii, Sabethes ignotus, Sa. luxodens, Sa. undosus, Shannoniana fluviatilis, Trichoprosopon compressum, Tr. digitatum, Tr. evansae, Tr. pallidiventer s.l., Tr. pallidiventer s.s., Wyeomyia arthrostigma, Wy. oblita, Wy. ulocoma, and Wy. undulata. The species Sa. luxodens and Wy. undulata constitute new records for Colombia. These records broaden the knowledge of this important group that includes some important species related to the arbovirus transmission. Records are from the northern Colombian Andes, a region noted for coffee cultivation and ecotourism. PMID:26181687

  17. Size class structure, growth rates, and orientation of the central Andean cushion Azorella compacta

    Directory of Open Access Journals (Sweden)

    Catherine Kleier

    2015-03-01

    Full Text Available Azorella compacta (llareta; Apiaceae forms dense, woody, cushions and characterizes the high elevation rocky slopes of the central Andean Altiplano. Field studies of an elevational gradient of A. compacta within Lauca National Park in northern Chile found a reverse J-shape distribution of size classes of individuals with abundant small plants at all elevations. A new elevational limit for A. compacta was established at 5,250 m. A series of cushions marked 14 years earlier showed either slight shrinkage or small degrees of growth up to 2.2 cm yr−1. Despite their irregularity in growth, cushions of A. compacta show a strong orientation, centered on a north-facing aspect and angle of about 20° from horizontal. This exposure to maximize solar irradiance closely matches previous observations of a population favoring north-facing slopes at a similar angle. Populations of A. compacta appear to be stable, or even expanding, with young plants abundant.

  18. Lower and Middle Devonian Malvinokaffric ostracods from the Precordillera Basin of San Juan, Argentina

    Science.gov (United States)

    Salas, María J.; Rustán, Juan J.; Sterren, Andrea F.

    2013-08-01

    Ostracod from the upper Lower to Middle Devonian rocks of the Argentine Precordillera Basin (Talacasto and Punta Negra formations) are studied. One new genus Pircawayra nov. gen., and five species (including three new: Pircawayra gigantea nov. gen. and sp., Lapazites trinodis nov. sp. and Keslingiella? teresae nov. sp.) are defined. The recorded ostracod fauna closely resembles that coeval from Bolivia and South Africa, exhibiting a remarkable endemism, not only at the genus level, but also at the species level. In addition to its low-diversity, the Malvinokaffric ostracod association is also characterized by having large, thick, coarsely ornamented and swollen valves. The similar ostracod composition from the Andean and South African basins suggests faunal exchange between these two areas. Based on the ostracod faunas, the Malvinokaffric Realm is clearly recognizable at least up to the Middle Devonian.

  19. Thoracic skeletal morphology and high-altitude hypoxia in Andean prehistory.

    Science.gov (United States)

    Weinstein, Karen J

    2007-09-01

    Living humans from the highland Andes exhibit antero-posteriorly and medio-laterally enlarged chests in response to high-altitude hypoxia. This study hypothesizes that morphological responses to high-altitude hypoxia should also be evident in pre-Contact Andean groups. Thoracic skeletal morphology in four groups of human skeletons (N = 347) are compared: two groups from coastal regions (Ancón, Peru, n = 79 and Arica, Chile, n = 123) and two groups from high altitudes (San Pedro de Atacama, Chile, n = 102 and Machu Picchu and Cuzco, Peru, n = 43). Osteometric variables that represent proportions of chest width and depth include sternal and clavicular lengths and breadths and rib length, curvature, and area. Each variable was measured relative to body size, transformed into logarithmic indices, and compared across sex-specific groups using ANOVA and Tukey multiple comparison tests. Atacama highlanders have the largest sternal and clavicular proportions and ribs with the greatest area and least amount of curvature, features that suggest an antero-posteriorly deep and mediolaterally wide thoracic skeleton. Ancón lowlanders exhibit proportions indicating narrower and shallower chests. Machu Picchu and Cuzco males cluster with the other highland group in rib curvature and area at the superior levels of the thorax, whereas chest proportions in Machu Picchu and Cuzco females resemble those of lowlanders. The variation in Machu Picchu and Cuzco males and females is interpreted as the result of population migrations. The presence of morphological traits indicative of enlarged chests in some highland individuals suggests that high-altitude hypoxia was an environmental stressor shaping the biology of highland Andean groups during the pre-Contact period. PMID:17503449

  20. A novel candidate region for genetic adaptation to high altitude in Andean populations.

    Directory of Open Access Journals (Sweden)

    Guido Valverde

    Full Text Available Humans living at high altitude (≥ 2,500 meters above sea level have acquired unique abilities to survive the associated extreme environmental conditions, including hypoxia, cold temperature, limited food availability and high levels of free radicals and oxidants. Long-term inhabitants of the most elevated regions of the world have undergone extensive physiological and/or genetic changes, particularly in the regulation of respiration and circulation, when compared to lowland populations. Genome scans have identified candidate genes involved in altitude adaption in the Tibetan Plateau and the Ethiopian highlands, in contrast to populations from the Andes, which have not been as intensively investigated. In the present study, we focused on three indigenous populations from Bolivia: two groups of Andean natives, Aymara and Quechua, and the low-altitude control group of Guarani from the Gran Chaco lowlands. Using pooled samples, we identified a number of SNPs exhibiting large allele frequency differences over 900,000 genotyped SNPs. A region in chromosome 10 (within the cytogenetic bands q22.3 and q23.1 was significantly differentiated between highland and lowland groups. We resequenced ~1.5 Mb surrounding the candidate region and identified strong signals of positive selection in the highland populations. A composite of multiple signals like test localized the signal to FAM213A and a related enhancer; the product of this gene acts as an antioxidant to lower oxidative stress and may help to maintain bone mass. The results suggest that positive selection on the enhancer might increase the expression of this antioxidant, and thereby prevent oxidative damage. In addition, the most significant signal in a relative extended haplotype homozygosity analysis was localized to the SFTPD gene, which encodes a surfactant pulmonary-associated protein involved in normal respiration and innate host defense. Our study thus identifies two novel candidate genes and

  1. Hydrological connectivity of alluvial Andean valleys: a groundwater/surface-water interaction case study in Ecuador

    Science.gov (United States)

    Guzmán, Pablo; Anibas, Christian; Batelaan, Okke; Huysmans, Marijke; Wyseure, Guido

    2016-06-01

    The Andean region is characterized by important intramontane alluvial and glacial valleys; a typical example is the Tarqui alluvial plain, Ecuador. Such valley plains are densely populated and/or very attractive for urban and infrastructural development. Their aquifers offer opportunities for the required water resources. Groundwater/surface-water (GW-SW) interaction generally entails recharge to or discharge from the aquifer, dependent on the hydraulic connection between surface water and groundwater. Since GW-SW interaction in Andean catchments has hardly been addressed, the objectives of this study are to investigate GW-SW interaction in the Tarqui alluvial plain and to understand the role of the morphology of the alluvial valley in the hydrological response and in the hydrological connection between hillslopes and the aquifers in the valley floor. This study is based on extensive field measurements, groundwater-flow modelling and the application of temperature as a groundwater tracer. Results show that the morphological conditions of a valley influence GW-SW interaction. Gaining and losing river sections are observed in narrow and wide alluvial valley sections, respectively. Modelling shows a strong hydrological connectivity between the hillslopes and the alluvial valley; up to 92 % of recharge of the alluvial deposits originates from lateral flow from the hillslopes. The alluvial plain forms a buffer or transition zone for the river as it sustains a gradual flow from the hills to the river. Future land-use planning and development should include concepts discussed in this study, such as hydrological connectivity, in order to better evaluate impact assessments on water resources and aquatic ecosystems.

  2. Acceleration and novelty: community restoration speeds recovery and transforms species composition in Andean cloud forest.

    Science.gov (United States)

    Wilson, Sarah Jane; Rhemtulla, Jeanine M

    2016-01-01

    Community-based tropical forest restoration projects, often promoted as a win-win solution for local communities and the environment, have increased dramatically in number in the past decade. Many such projects are underway in Andean cloud forests, which, given their extremely high biodiversity and history of extensive clearing, are understudied. This study investigates the efficacy of community-based tree-planting projects to accelerate cloud forest recovery, as compared to unassisted natural regeneration. This study takes place in northwest Andean Ecuador, where the majority of the original, highly diverse cloud forests have been cleared, in five communities that initiated tree-planting projects to restore forests in 2003. In 2011, we identified tree species along transects in planted forests (n = 5), naturally regenerating forests (n = 5), and primary forests (n = 5). We also surveyed 120 households about their restoration methods, tree preferences, and forest uses. We found that tree diversity was higher in planted than in unplanted secondary forest, but both were less diverse than primary forests. Ordination analysis showed that all three forests had distinct species compositions, although planted forests shared more species with primary forests than did unplanted forests. Planted forests also contained more animal-dispersed species in both the planted canopy and in the unplanted, regenerating understory than unplanted forests, and contained the highest proportion of species with use value for local people. While restoring forest increased biodiversity and accelerated forest recovery, restored forests may also represent novel ecosystems that are distinct from the region's previous ecosystems and, given their usefulness to people, are likely to be more common in the future. PMID:27039520

  3. Genome-Wide Association Study of Anthracnose Resistance in Andean Beans (Phaseolus vulgaris.

    Directory of Open Access Journals (Sweden)

    Grady H Zuiderveen

    Full Text Available Anthracnose is a seed-borne disease of common bean (Phaseolus vulgaris L. caused by the fungus Colletotrichum lindemuthianum, and the pathogen is cosmopolitan in distribution. The objectives of this study were to identify new sources of anthracnose resistance in a diverse panel of 230 Andean beans comprised of multiple seed types and market classes from the Americas, Africa, and Europe, and explore the genetic basis of this resistance using genome-wide association mapping analysis (GWAS. Twenty-eight of the 230 lines tested were resistant to six out of the eight races screened, but only one cultivar Uyole98 was resistant to all eight races (7, 39, 55, 65, 73, 109, 2047, and 3481 included in the study. Outputs from the GWAS indicated major quantitative trait loci (QTL for resistance on chromosomes, Pv01, Pv02, and Pv04 and two minor QTL on Pv10 and Pv11. Candidate genes associated with the significant SNPs were detected on all five chromosomes. An independent QTL study was conducted to confirm the physical location of the Co-1 locus identified on Pv01 in an F4:6 recombinant inbred line (RIL population. Resistance was determined to be conditioned by the single dominant gene Co-1 that mapped between 50.16 and 50.30 Mb on Pv01, and an InDel marker (NDSU_IND_1_50.2219 tightly linked to the gene was developed. The information reported will provide breeders with new and diverse sources of resistance and genomic regions to target in the development of anthracnose resistance in Andean beans.

  4. Genome-Wide Association Study of Anthracnose Resistance in Andean Beans (Phaseolus vulgaris).

    Science.gov (United States)

    Zuiderveen, Grady H; Padder, Bilal A; Kamfwa, Kelvin; Song, Qijian; Kelly, James D

    2016-01-01

    Anthracnose is a seed-borne disease of common bean (Phaseolus vulgaris L.) caused by the fungus Colletotrichum lindemuthianum, and the pathogen is cosmopolitan in distribution. The objectives of this study were to identify new sources of anthracnose resistance in a diverse panel of 230 Andean beans comprised of multiple seed types and market classes from the Americas, Africa, and Europe, and explore the genetic basis of this resistance using genome-wide association mapping analysis (GWAS). Twenty-eight of the 230 lines tested were resistant to six out of the eight races screened, but only one cultivar Uyole98 was resistant to all eight races (7, 39, 55, 65, 73, 109, 2047, and 3481) included in the study. Outputs from the GWAS indicated major quantitative trait loci (QTL) for resistance on chromosomes, Pv01, Pv02, and Pv04 and two minor QTL on Pv10 and Pv11. Candidate genes associated with the significant SNPs were detected on all five chromosomes. An independent QTL study was conducted to confirm the physical location of the Co-1 locus identified on Pv01 in an F4:6 recombinant inbred line (RIL) population. Resistance was determined to be conditioned by the single dominant gene Co-1 that mapped between 50.16 and 50.30 Mb on Pv01, and an InDel marker (NDSU_IND_1_50.2219) tightly linked to the gene was developed. The information reported will provide breeders with new and diverse sources of resistance and genomic regions to target in the development of anthracnose resistance in Andean beans. PMID:27270627

  5. Uptake of Hg2+ by picocyanobacteria in natural water from four Andean lakes

    Directory of Open Access Journals (Sweden)

    Diéguez M.C.

    2014-07-01

    Full Text Available In lake food webs, planktonic bacteria and algae represent the greatest bioconcentration step for Hg2+ and monomethyl-Hg (MeHg. As they are the most abundant organisms in planktonic trophic webs and also the main food resource for herbivorous plankton, they can mobilize large amounts of Hg to higher trophic levels. In Andean Patagonian lakes (Argentina, dissolved organic matter (DOM concentration and character, coupled with photo-reactions, play a central role in the complexation of Hg2+ in the water column and can even regulate the uptake of Hg2+ by planktonic algae. In this investigation we evaluated the DOM character of natural waters (NW from four Andean lakes and studied its influence on the uptake of 197Hg2+ in a strain of the picocyanobacteria Synechococcus by using Hg2+ labeled with 197Hg2+. The uptake of radiolabeled Hg2+ by Synechococcus showed different magnitude in NW of lakes Moreno, El Trébol, Morenito and Escondido. Increasing lake DOM concentration reduced the bioavailability of Hg2+ as indicated by the lower uptakes rates found in NW with higher complexity and concentration of the DOM pool. Uptakes of Hg2+ by this picocyanobacteria contrasted among NW from pelagic (surface and bottom and littoral compartments of Lake Escondido which suggest that the entry of this metal may be highly variable even in the same environment. The study of the uptake of radiolabeled Hg2+ in a set of dilutions of NW from Lake Escondido demonstrated that the bioavailability of Hg2+ decrease with increasing DOM concentration.

  6. Genome-Wide Association Study of Anthracnose Resistance in Andean Beans (Phaseolus vulgaris)

    Science.gov (United States)

    Zuiderveen, Grady H.; Padder, Bilal A.; Kamfwa, Kelvin; Song, Qijian; Kelly, James D.

    2016-01-01

    Anthracnose is a seed-borne disease of common bean (Phaseolus vulgaris L.) caused by the fungus Colletotrichum lindemuthianum, and the pathogen is cosmopolitan in distribution. The objectives of this study were to identify new sources of anthracnose resistance in a diverse panel of 230 Andean beans comprised of multiple seed types and market classes from the Americas, Africa, and Europe, and explore the genetic basis of this resistance using genome-wide association mapping analysis (GWAS). Twenty-eight of the 230 lines tested were resistant to six out of the eight races screened, but only one cultivar Uyole98 was resistant to all eight races (7, 39, 55, 65, 73, 109, 2047, and 3481) included in the study. Outputs from the GWAS indicated major quantitative trait loci (QTL) for resistance on chromosomes, Pv01, Pv02, and Pv04 and two minor QTL on Pv10 and Pv11. Candidate genes associated with the significant SNPs were detected on all five chromosomes. An independent QTL study was conducted to confirm the physical location of the Co-1 locus identified on Pv01 in an F4:6 recombinant inbred line (RIL) population. Resistance was determined to be conditioned by the single dominant gene Co-1 that mapped between 50.16 and 50.30 Mb on Pv01, and an InDel marker (NDSU_IND_1_50.2219) tightly linked to the gene was developed. The information reported will provide breeders with new and diverse sources of resistance and genomic regions to target in the development of anthracnose resistance in Andean beans. PMID:27270627

  7. Hydrological differentiation and spatial distribution of high altitude wetlands in a semi-arid Andean region derived from satellite data

    Directory of Open Access Journals (Sweden)

    M. Otto

    2011-01-01

    Full Text Available High Altitude Wetlands of the Andes (HAWA are unique types of wetlands within the semi-arid high Andean region. Knowledge about HAWA has been derived mainly from studies at single sites within different parts of the Andes at only small time scales. On the one hand HAWA depend on water provided by glacier streams, snow melt or precipitation. On the other hand, they are suspected to influence hydrology through water retention and vegetation growth altering stream flow velocity. We derived HAWA land cover from satellite data at regional scale and analysed changes in connection with precipitation over the last decade. Perennial and temporal HAWA subtypes can be distinguished by seasonal changes of photosynthetically active vegetation (PAV indicating the perennial or temporal availability of water during the year. HAWA have been delineated within a region of 11 000 km2 situated in the Northwest of Lake Titicaca. The multi temporal classification method used Normalized Differenced Vegetation Index (NDVI and Normalized Differenced Infrared Index (NDII data derived from two Landsat ETM+ scenes at the end of austral winter (September 2000 and at the end of austral summer (May 2001. The mapping result indicates an unexpected high abundance of HAWA covering about 800 km2 of the study region (6%. Annual HAWA mapping was computed using NDVI 16-day composites of Moderate Resolution Imaging Spectroradiometer (MODIS. Analyses on the reletation between HAWA and precipitation was based on monthly precipitation data of the Tropical Rain Measurement Mission (TRMM 3B43 and MODIS Eight Day Maximum Snow Extent data (MOD10A2 from 2000 to 2010. We found HAWA subtype specific dependencies to precipitation conditions. Strong relation exists between perennial HAWA and snow fall (r2: 0.82 in dry austral winter months (June to August and between temporal HAWA and precipitation (r2: 0.75 during austral summer (March to

  8. Constraints on the origin and evolution of magmas in the Payún Matrú Volcanic Field, Quaternary Andean back-arc of western Argentina

    DEFF Research Database (Denmark)

    Hernadno, I R; Aragón, E; Frei, Robert;

    2014-01-01

    The Payún Matrú Volcanic Field (Pleistocene–Holocene) is located in the Andean back-arc of the Southern Volcanic Zone, western Argentina, and is contemporaneous with the Andean volcanic arc at the same latitude. It includes two polygenetic, mostly trachytic volcanoes: Payún Matrú (with a summit c...... geophysical results (mantle tomography and electrical conductivity anomalies) suggest that magmas were generated by decompression-induced melting of upwelling mantle...

  9. Diversity of Andean amphibians of the Tamá National Natural Park in Colombia: a survey for the presence of Batrachochytrium dendrobatidis

    Directory of Open Access Journals (Sweden)

    Acevedo, A. A.

    2016-01-01

    Full Text Available Changes in diversity and possible decreases in populations of amphibians have not yet been determined in many areas in the Andes. This study aimed to develop an inventory of the biodiversity of amphibians in the Andean areas of the Tamá National Natural Park (Tamá NNP and to evaluate the patterns of infection by Batrachochytrium dendrobatidis (Bd in preserved and degraded areas. We performed samplings focused on three habitats (forest, open areas and streams in four localities from 2,000 to 3,200 m in altitude. Fourteen species were recorded, 12 of which were positive for Bd. A total of 541 individuals were diagnosed and 100 were positive. Our analyses showed that preserved areas play an important role in keeping many individuals Bd–free as compared to those in degraded areas. This was the first study to evaluate diversity and infection by Bd in the northeast region of Colombia. Our findings may help improve our knowledge of the diversity of amphibian species in the area and facilitate the implementation of action plans to mitigate the causes associated with the decrease in amphibian populations.

  10. Evolution of the Rembrandt impact basin on Mercury.

    Science.gov (United States)

    Watters, Thomas R; Head, James W; Solomon, Sean C; Robinson, Mark S; Chapman, Clark R; Denevi, Brett W; Fassett, Caleb I; Murchie, Scott L; Strom, Robert G

    2009-05-01

    MESSENGER's second Mercury flyby revealed a ~715-kilometer-diameter impact basin, the second-largest well-preserved basin-scale impact structure known on the planet. The Rembrandt basin is comparable in age to the Caloris basin, is partially flooded by volcanic plains, and displays a unique wheel-and-spoke-like pattern of basin-radial and basin-concentric wrinkle ridges and graben. Stratigraphic relations indicate a multistaged infilling and deformational history involving successive or overlapping phases of contractional and extensional deformation. The youngest deformation of the basin involved the formation of a approximately 1000-kilometer-long lobate scarp, a product of the global cooling and contraction of Mercury. PMID:19407197

  11. Late Quaternary stratigraphy, sedimentology, and geochemistry of an underfilled lake basin in the Puna (north-west Argentina)

    Science.gov (United States)

    McGlue, Michael M.; Cohen, Andrew S.; Ellis, Geoffrey S.; Kowler, Andrew L.

    2013-01-01

    Depositional models of ancient lakes in thin-skinned retroarc foreland basins rarely benefit from appropriate Quaternary analogues. To address this, we present new stratigraphic, sedimentological and geochemical analyses of four radiocarbon-dated sediment cores from the Pozuelos Basin (PB; northwest Argentina) that capture the evolution of this low-accommodation Puna basin over the past ca. 43 cal kyr. Strata from the PB are interpreted as accumulations of a highly variable, underfilled lake system represented by lake-plain/littoral, profundal, palustrine, saline lake and playa facies associations. The vertical stacking of facies is asymmetric, with transgressive and thin organic-rich highstand deposits underlying thicker, organic-poor regressive deposits. The major controls on depositional architecture and basin palaeogeography are tectonics and climate. Accommodation space was derived from piggyback basin-forming flexural subsidence and Miocene-Quaternary normal faulting associated with incorporation of the basin into the Andean hinterland. Sediment and water supply was modulated by variability in the South American summer monsoon, and perennial lake deposits correlate in time with several well-known late Pleistocene wet periods on the Altiplano/Puna plateau. Our results shed new light on lake expansion–contraction dynamics in the PB in particular and provide a deeper understanding of Puna basin lakes in general.

  12. Biogeographic patterns of Colombian frogs and toads

    International Nuclear Information System (INIS)

    Using the data provided in Ruiz-Carranza et al. (1996) the distributions of the 540 species of frogs and toads are partitioned among ten ecogeographic units of Colombia defined on the basis of precipitation and elevation. Some lowlands areas (pacific lowlands, Amazonian) exhibit high diversity (85-94 species) but lowlands areas in general are impoverished (30-52 species), especially when contrasted with upland areas. The three Andean cordilleras harbor between 87 and 121 species of frogs and toads, demonstrating that the biodiversity of Colombia resides primarily in its montane components, not in its lowland rain forests. When biological endemicity is separated from political endemicity, five areas of high endemicity remain (the three Andean cordilleras, the Sierra Nevada de Santa Marta, and the pacific lowlands). We endeavor to explain this description by recourse to cladistic analyses of several groups of leptodactylid frogs where we find that the general pattern of diversification is by means of horizontal diversification (allopatric speciation) with a minor contribution from vertical diversification

  13. Analysis of Genetic Variability among thirty accessions of Andean Lupin (Lupinus mutabilis Sweet using ISSR molecular markers

    Directory of Open Access Journals (Sweden)

    Michelle C. Chirinos-Arias

    2015-03-01

    Full Text Available In order to make the genetic variability analysis among thirty accessions of andean lupine (L. mutabilis Sweet belonging to Agrarian Innovation National Institute (INIA Seed Bank. DNA was extracted from 300 plants and we made bulks. We standardized amplification protocol of Inter Simple Sequence Repeat (ISSR primers, we chose the most polymorphic primers to run in acrylamide gel. We found 255 ISSR loci with 8 primers. It was found high genetic variability of the samples under study by ISSR markers. Also observed relatively high polymorphism for autogamous species such as andean lupine. Finally phenograms showed a relationship with the geographical location, possibly due to in situ gene flow due to the exchange or sale of seeds in markets near the collection area.

  14. Culturas indígenas de la región andina - Indian cultures of the Andean region

    Directory of Open Access Journals (Sweden)

    MOLNÁR, Gábor

    2014-09-01

    Full Text Available The A ndean region is an autonomous and well delimited geographical region of Latin America, but from a cultural geographical point of view it is not concerned as a completely homogeneous territory. The physical geography given by the chains of the Andean mountains was the common basis for several civilizations and cultures of different levels of development and different extensions in time and in space appeared there during thousands of years. Most of them – not without reference to the arrival of the Europeans – completely or partially disappeared. However some elements of their cultures are taking part of the actual mestic reality that is in continuous changing nowadays too. At the same time the natives living today in the Andean region, from the Guajira Peninsula to the Tierra del Fuego, belong to dozens of etnical groups and aproximately 10-15 million people among all Indians of Latin America live in this region.

  15. Preliminary checklist of the vascular flora of the Sub-Andean forest at Cuchilla El Fara (Santander-Colombia)

    International Nuclear Information System (INIS)

    A preliminary checklist of the vascular flora of the sub-Andean forest of the Cuchilla El Fara is present ed. El Fara is located at the Guantiva - La Rusia - Iguaque biological corridor, in the municipalities of Charala, Gambita, and Suaita (Santander-Colombia). Information on habit, local altitudinal range, and collection number is recorded for each species. A total of 409 species of vascular plants included in 226 genera, and 105 families were recorded. The families with the highest number of genera were Rubiaceae (18), Asteraceae (10), Melastomataceae (10), Orchidaceae (10), Euphorbiaceae (8), Arecaceae (7) and Fabaceae (7). At specific level, the best represented families were Rubiaceae (33), Melastomataceae (28), Lauraceae (21), Asteraceae (17), Araceae (17), Orchidaceae (17) and Gesneriaceae (15). The affinities of the flora with other Neotropical sub-Andean forests are discussed. Finally, species of all IUCN threat categories are highlighted so that the information presented here can make a contribution to restoration and conservation programs.

  16. A stratigraphical-geochemical study on the Chaco Paraná continental rift basin- An approach study based on regional sedimentology and drill-hole core analyses,South América

    Institute of Scientific and Technical Information of China (English)

    Roberto Torra

    2006-01-01

    This paper is focused on a geologic "regional rift basin system pattern" and its stratigraphical-geochemical relationship. This is mainly based on the littoral shallow marine sedimentary succession paleogeography and deposits. These successions characterize the large extensional intracratonic Chaco rift basin system evolved from the Upper Cretaceous ( Late Campanian-Senonian-Maastrichtian-Early Paleocene) to Quaternary time. The siliciclastic littoral shallow marine successions were deposited from Early Senonian-Maastrichtian to Late Miocene during three main successive littoral shallow marine transgressions of continental extension.These transgressions happened over the wide pediplanized terrains of South America. These lands exist west of the more positive areas, between the Brazilian Shield and the foreland massifs that were settled in the more westernwards areas. Later, these regional foreland massifs were coupled and raised to the Andean Orogen Belt during the last 5 million years.The extensive intracratonic pediplanized low topographic relief areas were the reservoirs of siliciclastic littoral shallow marine succession deposits during the three successive widespread vast continental littoral shallow marine transgressions.The first transgression began at the Latest Campanian-Senonian and/or Early Maastrichtian time. After this episode, the sedimentary depositional systems continued during the Cenozoic until the Latest Miocene. These successions constitute a major allostratigraphic unit.The limit with underlying units is the regional unconformity between the regional volcanic event (Jurassic-Cretacic and interleaved eolianite sandstones) at the base and the undifferentiated Quaternary sediments (called as the Pampeano and Post-Pampeano Formations sensu lato). Based on many facies analyses there had been checked out different levels in the eustatic sea level variations within the allostratigraphic unit.Three major stages of extensional climax were recognized and

  17. Population structure and spatial distribution pattern of Picea crassifolia in Dayekou Basin of Qilian Mountains%祁连山大野口流域青海云杉种群结构和空间分布格局

    Institute of Scientific and Technical Information of China (English)

    李效雄; 刘贤德; 赵维俊

    2012-01-01

    research object which grows in Dayekou Basin of the Qilian Mountains, by setting up a major quadrate method investigation and analyzing its population structure and spatial distribution pattern. The method of adjacent grid method was used to analyze the entire individual's data of 100 m×l m simple investigation, the population dynamics and DBH, tree height and crown breadth frequency distribution and 6 kinds of aggregation intensity indexes were used to analyze the structure and spatial distribution pattern of Picea crassifolia population. The results show that population dynamics of Picea crassifolia population belonging to increasing type. DBH size class frequency distribution of Picea crassifolia population is "pour J" type, DBH size class with the change of individual level is quite fit for the logarithmic equation y = 219. 32 In (x) + 482. 67 (R2 = 0. 9638, P < 0. 01), differentiation index of DBH is 0.48, the differences of DBH in the population for each individual is obvious; Frequency distribution of the tree height is " intermittent" type, Tree height size class and individual level can be explained by quadratic equation y = 0. 795 x2 - 31. 23 x + 285. 1 (R2 = 0. 603, P < 0. 01), differentiation index of tree height is 0.55, tree height difference is evident; The logarithmic equation y = 5. 912 ln (x) 4. 2493 (R2 = 0. 603, P < 0. 01) can be used to show the relation between tree height and DBH; Crown breadth size class and individual are accorded with equation y -5. 3176 x3 -91. 759 x2 + 408. 88 x - 173. 87 (R2 = 0. 8355, P < 0. 01), differentiation index of crown breadth is 0.53, the differentiation crown breadth of population individual is apparent. In general, Picea crassifolia seedlings is relatively rich, natural regeneration ability is strong, at present the performance of Picea crassifolia population is the mature stable populations. On the spatial distribution pattern, Picea crassifolia population space distribution pattern is gathered as plaques form

  18. Can Andean medicine coexist with biomedical healthcare? A comparison of two rural communities in Peru and Bolivia

    Directory of Open Access Journals (Sweden)

    Mathez-Stiefel Sarah-Lan

    2012-07-01

    Full Text Available Abstract Background It is commonly assumed that indigenous medical systems remain strong in developing countries because biomedicine is physically inaccessible or financially not affordable. This paper compares the health-seeking behavior of households from rural Andean communities at a Peruvian and a Bolivian study site. The main research question was whether the increased presence of biomedicine led to a displacement of Andean indigenous medical practices or to coexistence of the two healing traditions. Methodology Open-ended interviews and free listing exercises were conducted between June 2006 and December 2008 with 18 households at each study site. Qualitative identification of households’ therapeutic strategies and use of remedies was carried out by means of content analysis of interview transcriptions and inductive interference. Furthermore, a quantitative assessment of the incidence of culture-bound illnesses in local ethnobiological inventories was performed. Results Our findings indicate that the health-seeking behavior of the Andean households in this study is independent of the degree of availability of biomedical facilities in terms of quality of services provided, physical accessibility, and financial affordability, except for specific practices such as childbirth. Preference for natural remedies over pharmaceuticals coexists with biomedical healthcare that is both accessible and affordable. Furthermore, our results show that greater access to biomedicine does not lead to less prevalence of Andean indigenous medical knowledge, as represented by the levels of knowledge about culture-bound illnesses. Conclusions The take-home lesson for health policy-makers from this study is that the main obstacle to use of biomedicine in resource-poor rural areas might not be infrastructural or economic alone. Rather, it may lie in lack of sufficient recognition by biomedical practitioners of the value and importance of indigenous medical systems

  19. Crown Jewel of the Fleet: Design, Construction, and Use of the Seagoing Balsa of the Pre-Columbian Andean Coast

    OpenAIRE

    Emanuel, Jeffrey Paul

    2012-01-01

    The seaworthiness of the balsa sailing raft, and the seafaring aptitude of those who built and sailed it, has been the subject of critically biased, often conflicting accounts over the nearly five centuries since contact. This paper objectively marshals historical evidence to recover the preColumbian design and construction of this ‘Crown Jewel’ of the coastal Andean fleet. Sailing balsas were constructed of balsa tree (ochroma spp.) trunks lashed together with henequen, covered with one or m...

  20. Assessing the Influence of Global Climate and Anthropogenic Activities on the Water Balance of an Andean Lake

    OpenAIRE

    Julio Cañón; Juan Valdes

    2011-01-01

    Tropical regions along the Andean Cordillera face an uncertain future as mountain lakes and snow peaks exhibit receding trends associated with factors such as climatic precursors and local anthropogenic activities. Tota, the largest mountain lake in the Colombian Andes, exemplifies the role played by these factors on the lake's hydrologic evolution. A monthly water balance in Tota Lake was performed using available hydrological information from 1958 to 2007 to address interannual and multiann...

  1. Characterization of Bacillus isolates of potato rhizosphere from andean soils of Peru and their potential PGPR characteristics

    OpenAIRE

    Pamela Calvo; Ernesto Ormeño-Orrillo; Esperanza Martínez-Romero; Doris Zúñiga

    2010-01-01

    Bacillus spp. are well known rhizosphere residents of many crops and usually show plant growth promoting (PGP) activities that include biocontrol capacity against some phytopatogenic fungi. Potato crops in the Andean Highlands of Peru face many nutritional and phytophatogenic problems that have a significant impact on production. In this context is important to investigate the natural presence of these microorganisms in the potato rhizosphere and propose a selective screening to find promisin...

  2. Extreme High Prevalence of a Defective Mannose-Binding Lectin (MBL2) Genotype in Native South American West Andean Populations

    DEFF Research Database (Denmark)

    Sandoval, José Raul; Madsen, Hans O; De Stefano, Gianfranco;

    2014-01-01

    variation in indigenous individuals from 12 different West Central South America localities spanning from the desert coast, high altitude Andean plates and the Amazon tropical forest within the territories of Peru (n = 249) (Departments of Loreto, Ucayali, Lambayeque, Junin, Ayacucho, Huancayo and Puno...... high prevalence of the MBL2 LYPB variant causing low levels of functional MBL in serum may mainly reflect a random distribution due to a population bottleneck in the founder populations....

  3. Seismic imaging of a convergent continental margin and plateau in the central Andes (Andean Continental Research Project 1996 (ANCORP'96))

    OpenAIRE

    Onno Oncken; Stephan V. Sobolev; Manfred Stiller; Günter Asch; Christian Haberland; James Mechie; Xiaohui Yuan; E. Lüchen; P. Giese; P. Wigger; Stefan Lüth; E. Scheuber; H.-J. Götze; H. Brasse; S. Buske

    2003-01-01

    A 400-km-long seismic reflection profile (Andean Continental Research Project 1996 (ANCORP'96)) and integrated geophysical experiments (wide-angle seismology, passive seismology, gravity, and magnetotelluric depth sounding) across the central Andes (21°S) observed subduction of the Nazca plate under the South American continent. An east dipping reflector (Nazca Reflector) is linked to the down going oceanic crust and shows increasing downdip intensity before gradual breakdown below 80 km. We ...

  4. Hydrological differentiation and spatial distribution of high altitude wetlands in a semi-arid Andean region derived from satellite data

    OpenAIRE

    Otto, M.; Scherer, D.; J. Richters

    2011-01-01

    High Altitude Wetlands of the Andes (HAWA) belong to a unique type of wetland within the semi-arid high Andean region. Knowledge about HAWA has been derived mainly from studies at single sites within different parts of the Andes at only small time scales. On the one hand, HAWA depend on water provided by glacier streams, snow melt or precipitation. On the other hand, they are suspected to influence hydrology through water retention and vegetation growth altering stream flow velocity. W...

  5. Hydrological differentiation and spatial distribution of high altitude wetlands in a semi-arid Andean region derived from satellite data

    OpenAIRE

    Otto, M.; Scherer, D.; J. Richters

    2011-01-01

    High Altitude Wetlands of the Andes (HAWA) belong to a unique type of wetland within the semi-arid high Andean region. Knowledge about HAWA has been derived mainly from studies at single sites within different parts of the Andes at only small time scales. On the one hand, HAWA depend on water provided by glacier streams, snow melt or precipitation. On the other hand, they are suspected to influence hydrology through water retention and veg...

  6. Hydrological differentiation and spatial distribution of high altitude wetlands in a semi-arid Andean region derived from satellite data

    OpenAIRE

    Otto, M.; Scherer, D.; J. Richters

    2011-01-01

    High Altitude Wetlands of the Andes (HAWA) are unique types of wetlands within the semi-arid high Andean region. Knowledge about HAWA has been derived mainly from studies at single sites within different parts of the Andes at only small time scales. On the one hand HAWA depend on water provided by glacier streams, snow melt or precipitation. On the other hand, they are suspected to influence hydrology through water retention and vegetation growth altering stream flow velocity. We derive...

  7. Birds of Two Oceans? Trans-Andean and Divergent Migration of Black Skimmers (Rynchops niger cinerascens) from the Peruvian Amazon

    OpenAIRE

    Lisa C Davenport; Goodenough, Katharine S.; Haugaasen, Torbjørn

    2016-01-01

    Seasonal flooding compels some birds that breed in aquatic habitats in Amazonia to undertake annual migrations, yet we know little about how the complex landscape of the Amazon region is used seasonally by these species. The possibility of trans-Andes migration for Amazonian breeding birds has largely been discounted given the high geographic barrier posed by the Andean Cordillera and the desert habitat along much of the Pacific Coast. Here we demonstrate a trans-Andes route for Black Skimmer...

  8. Populations of Odontesthes (Teleostei: Atheriniformes) in the Andean region of Southern South America: body shape and hybrid individuals

    OpenAIRE

    Cecilia Conte-Grand; Julie Sommer; Guillermo Ortí; Víctor Cussac

    2015-01-01

    The original distribution area of the Patagonian 'pejerrey' Odontesthes hatcheri has been subjected to the introduction of a related species; the Bonaerensean 'pejerrey' Odontesthes bonariensis. This species currently coexists with O. hatcheri in lakes and reservoirs, and can interbreed and produce fertile hybrid offspring. The purposes of this study were; a) the extensive sampling of Patagonian and Andean-Cuyan populations of pejerrey, b) the species identification according to taxonomic key...

  9. Plant and animal endemism in the eastern Andean slope: challenges to conservation

    Directory of Open Access Journals (Sweden)

    Swenson Jennifer J

    2012-01-01

    Full Text Available Abstract Background The Andes-Amazon basin of Peru and Bolivia is one of the most data-poor, biologically rich, and rapidly changing areas of the world. Conservation scientists agree that this area hosts extremely high endemism, perhaps the highest in the world, yet we know little about the geographic distributions of these species and ecosystems within country boundaries. To address this need, we have developed conservation data on endemic biodiversity (~800 species of birds, mammals, amphibians, and plants and terrestrial ecological systems (~90; groups of vegetation communities resulting from the action of ecological processes, substrates, and/or environmental gradients with which we conduct a fine scale conservation prioritization across the Amazon watershed of Peru and Bolivia. We modelled the geographic distributions of 435 endemic plants and all 347 endemic vertebrate species, from existing museum and herbaria specimens at a regional conservation practitioner's scale (1:250,000-1:1,000,000, based on the best available tools and geographic data. We mapped ecological systems, endemic species concentrations, and irreplaceable areas with respect to national level protected areas. Results We found that sizes of endemic species distributions ranged widely (2 to > 200,000 km2 across the study area. Bird and mammal endemic species richness was greatest within a narrow 2500-3000 m elevation band along the length of the Andes Mountains. Endemic amphibian richness was highest at 1000-1500 m elevation and concentrated in the southern half of the study area. Geographical distribution of plant endemism was highly taxon-dependent. Irreplaceable areas, defined as locations with the highest number of species with narrow ranges, overlapped slightly with areas of high endemism, yet generally exhibited unique patterns across the study area by species group. We found that many endemic species and ecological systems are lacking national-level protection; a

  10. Taxonomic review of the species of Helina R.-D. (Diptera: Muscidae) from Andean-Patagonian forests.

    Science.gov (United States)

    Patitucci, Luciano Damián; Mulieri, Pablo Ricardo; Mariluis, Juan Carlos

    2016-01-01

    Helina Robineau-Desvoidy, 1830 is the second genus of Muscidae in terms of richness. This genus includes several species collected at high altitudes and high latitudes, and is poorly studied in the Neotropical region. Only 12 species of Helina have been recorded in the southern limit of South America in the Andean-Patagonian forests. In the present work, we studied all the species known from the Andean-Patagonian forests, with the exception of H. viola Malloch, 1934, present three new species, H. araucana sp. nov., H. dorada sp. nov., and H. ouina sp. nov., and provide the first description of the females of H. australis Carvalho & Pont, 1993 and H. rufoapicata Malloch, 1934. We also propose four new synonymies: H. nigrimana basilaris (Carvalho & Pont, 1993) and H. nigrimana grisea (Malloch, 1934) as new junior synonyms of H. nigrimana (Macquart, 1851); and H. fulvocalyptrata Malloch, 1934 and H. simplex Malloch, 1934 as new junior synonyms of H. chilensis Malloch, 1934. Finally, we provide a generic diagnosis and a new key for the Helina species of the Andean-Patagonian forests, as well as notes on the biology and distribution maps of each specimen, and discuss a preliminary contruction of groups of species. PMID:27515658

  11. Tectonic and climatic controls on late quaternary sedimentary processes in a neotectonic intramontane basin. (The Pitalito Basin, South Colombia).

    NARCIS (Netherlands)

    Bakker, J.

    1990-01-01

    The present study deals with the influence of tectonics and climatic changes on sedimentation patterns in the Quaternary Pitalito Basin (lat. 1°52'N, long. 76°02'W). This intramontane sedimentary basin is 15 km in width and 20 kin in length and is located in the Eastern Cordillera of the southern Co

  12. Biogeography and comparative cytogenetics between two populations of Hoplias malabaricus (Bloch, 1794 (Ostariophysi: Erythrinidae from coastal basins in the State of Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Uedson Pereira Jacobina

    2009-01-01

    Full Text Available The species Hoplias malabaricus is a predator fish found in nearly all cis-Andean basins. From a cytogenetic point of view, this species comprises, at least, seven differentiated karyomorphs. Several localities have been formerly analyzed in Brazil, however, some regions, such as Bahia State, remain underrepresented. Recently, the Brazilian Environment Ministry classified both Itapicuru and Contas river basins (entirely located within Bahia territory as priority conservation areas, whose biodiversity status lacks enough information. Therefore, the goal of the present work was to characterize, cytogenetically, populations of H. malabaricus from both basins, by using conventional staining, Ag-NOR and C-banding techniques. All specimens presented a diploid number of 2n = 40 with metacentric/submetacentric chromosomes, without differences between sexes, thereby representing the so-called "karyomorph F". The first metacentric pair presented a remarkably larger size in relation to the other pairs. The NORs were multiple, comprising the terminal region on long arms of two chromosomal pairs in both populations. However, the C-banding pattern was somewhat distinguishable between samples. Although sharing heterochromatic blocks at centromeric region of all chromosomes, the population from Itapicuru River basin appeared to have some more conspicuous blocks than those observed in the population from Contas River basin. The similar karyotype observed in both populations suggests a common geological history between them. The present results represent an advance in the knowledge about the cytogenetic pattern of H. malabaricus populations from poorly studied basins.A espécie Hoplias malabaricus é um predador que ocorre em praticamente todas as bacias cis-andinas. Sob o ponto de vista citogenético, ela compreende, pelo menos, sete cariomorfos diferenciáveis. Várias localidades já foram previamente analisadas no Brasil, porém, algumas regiões, como o

  13. Snowpack energy balance analysis using field measurements in an Andean watershed

    Science.gov (United States)

    Stehr, Alejandra

    2014-05-01

    Depending on the relative altitude and ambient temperature, Andean watersheds present important snow coverage during winter season. Snowpack stores significant amount of water which is released to surface runoff and groundwater when solar radiation increases, mainly during the spring and summer season, controlling the shape of the annual hydrograph and affecting the water balance at monthly and shorter scales. Field measurements of snow cover in those areas are difficult to perform due to adverse climatic and topographic conditions. Therefore, it is useful to support the hydrological characterization of watersheds located in the high mountains with models representing runoff from melting, for example, models based on the energy balance of the snowpack. The objective of this work is to characterize and quantify the energy flows that control the accumulation and melting of snow cover, using field measurements. The work was done on the upper Malleco watershed, which is located in the Andes Mountain Range (38°20' - 38°41' S and 71°13' - 71°35' W) and has an area of 27 km2, elevations vary between 900 to 1789 m a.m.s.l. For the calculation of the different the energy balance components, two weather stations were installed in the study area, which recorded data every 15 minutes. The variables measured were: global solar radiation, net radiation, shortwave and longwave radiation, air temperature, relative humidity, wind speed and direction, soil heat flux, precipitation and snow depth. Two analyzes were performed: 1) Energy Balance 2010. Two representative periods of accumulation (1st July to 31st July) and melting (10 September to 10 October) were selected in one of the stations. 2) Energy Balance 2011. Energy balance for a 15 days period of accumulation (July 19 to August 3, 2011) was with the aim of comparing both meteorological stations. In all cases hourly energy fluxes, snow water equivalent and daily snow depth were calculated. The latter was compared with the

  14. Climatic and lacustrine morphometric controls of diatom paleoproductivity in a tropical Andean lake

    Science.gov (United States)

    Bao, R.; Hernández, A.; Sáez, A.; Giralt, S.; Prego, R.; Pueyo, J. J.; Moreno, A.; Valero-Garcés, B. L.

    2015-12-01

    The coupling of lake dynamics with catchment biogeochemistry is considered the key element controlling primary production in mountain lakes at time scales of a few decades to millennia, yet little is known on the impacts of the morphometry of lakes throughout their ontogeny. As Lake Chungará (Central Andean Altiplano, northern Chile) experienced long-term lake-level fluctuations that strongly modified its area:volume ratio, it is an ideal system for exploring the relative roles that long-term climatic shifts and lake morphometry play on biosiliceous lacustrine productivity. In this paper, we review previous data on the percent contents of total organic carbon, total inorganic carbon, total nitrogen, total biogenic silica, isotopic composition of organic matter, carbonates, and diatom frustules, as well as data on the abundance of the chlorophycean Botryococcus braunii in this lake for the period 12,400-1300 cal yr BP. We also include new data on organic carbon and biogenic silica mass accumulation rates and the diatom assemblage composition of an offshore core dated using 14C and U/Th. Biosiliceous productivity in Lake Chungará was influenced by shifts in allochthonous nutrient inputs related to variability in precipitation. Humid phases dated at approx. 12,400 to 10,000 and 9600 to 7400 cal yr BP coincide with periods of elevated productivity, whereas decreases in productivity were recorded during arid phases dated at approx. 10,000 to 9600 and 7400 to 3550 cal yr BP (Andean mid-Holocene Aridity Period). However, morphometry-related in-lake controls led to a lack of a linear response of productivity to precipitation variability. During the late Glacial to early Holocene, lowstands facilitated complete water column mixing, prompting episodic massive blooms of a large centric diatom, Cyclostephanos cf. andinus. Thus, moderate productivity could be maintained, regardless of aridity, by this phenomenon of morphometric eutrophy during the early history of the lake

  15. Behavioural thermoregulation of the Andean toad (Bufo spinulosus) at high altitudes.

    Science.gov (United States)

    Sinsch, U

    1989-03-01

    The body temperature of free-ranging Andean toadsBufo spinulosus was measured either directly or radiotelemetrically during two 15-day periods at 3200 m elevation in the Mantaro Valley, Central Perú. All toads attempted to maintain their diurnal sum of body temperature within a narrow range. Consequently thermoregulatory behaviour differed according to cloud cover and precipitation. If the sky was clear, toads emerged from their hiding place and exposed themselves to solar radiation during 3-5 h in the morning. Core temperature increased up to 15° C above the air temperature in shade and reached maximum values of about 32° C. At air temperatures (in sun) exceeding 29° C, toads maintained body temperatures below 32° C by evaporative cooling. Following heliothermic heating during the moring toads retreated to the shade, thereby decreasing body temperature below air temperature. Under overcast sky toads remained exposed during the whole day displaying body temperatures at or slightly above ambient levels. Quantitative models to predict the core temperature of toads under the different weather conditions demonstrated that the substrate temperature was the main energy source accounting for 64.6-77.9% of total variance whereas air temperature was of minor importance (1.5-4.4%). The unexplained variance was probably due to evaporative cooling. The volume of urine stored into the urinary bladder of toads varied diurnally; during basking in the morning hours most bladders contained large volumes of urine, whereas during the afternoon the bladders were mostly empty. The bladder contents probably serve as water reserves during basking when evaporative water loss was high. Toads preferred sites that provided shady hiding places as well as sun-exposed bare soil within a radius of 5 m. However, they frequently changed their centers of activity and moved to other sites in 20-70 m distance after periods of 2-5 days. The helio-and thigmothermic behaviour of the Andean toad

  16. Spatial-temporal changes in Andean plateau climate and elevation from stable isotopes of mammal teeth

    Science.gov (United States)

    Bershaw, John; Garzione, Carmala N.; Higgins, Pennilyn; MacFadden, Bruce J.; Anaya, Frederico; Alvarenga, Herculano

    2010-01-01

    Paleoelevation constraints from fossil leaf physiognomy and stable isotopes of sedimentary carbonate suggest that significant surface uplift of the northern Andean plateau, on the order of 2.5 ± 1 km, occurred between ˜ 10.3 and 6.4 Ma. Independent spatial and temporal constraints on paleoelevation and paleoclimate of both the northern and southern plateau are important for understanding the distribution of rapid surface uplift and its relation to climate evolution across the plateau. This study focuses on teeth from modern and extinct mammal taxa (including notoungulates, pyrotheres, and litopterns) spanning ˜ 29 Ma to present, collected from the Altiplano and Eastern Cordillera of Bolivia (16.2°S to 21.4°S), and lowland Brazil. Tooth enamel of large, water-dependent mammals preserves a record of surface water isotopes and the type of plants that animals ingested while their teeth were mineralizing. Previous studies have shown that the δ18O of modern precipitation and surface waters decrease systematically with increasing elevations across the central Andes. Our results from high elevation sites between 3600 and 4100 m show substantially more positive δ18O values for late Oligocene tooth samples compared to < 10 Ma tooth δ18O values. Late Oligocene teeth collected from low elevation sites in southeast Brazil show δ18O values similar (within 2‰) to contemporaneous teeth collected at high elevation in the Eastern Cordillera. This affirms that the Andean plateau was at a very low elevation during the late Oligocene. Late Oligocene teeth from the northern Eastern Cordillera also yield consistent δ13C values of about - 9‰, indicating that the environment was semi-arid at that time. Latitudinal gradients in δ18O values of late Miocene to Pliocene fossil teeth are similar to modern values for large mammals, suggesting that by ˜ 8 Ma in the northern Altiplano and by ˜ 3.6 Ma in the southern Altiplano, both regions had reached high elevation and

  17. Peasant household type and its land use pattern in Melamchi basin of central mountainous area in Nepal%尼泊尔中部山区Melamchi流域农户类型及其土地利用方式

    Institute of Scientific and Technical Information of China (English)

    苏艺; 邓伟; 张继飞; Hriday Lal Koirala

    2016-01-01

    Changes in household livelihood strategy have provided a new research perspective for land utilization changes. By means of questionnaire survey, semi-structured interview, mathematical statistics and other research methods, this research conducts a systematic investigation on the households and land plots of 4 typical villages located at the Melamchi basin in the central mountainous areas in Nepal. Then based on the income combinations, this research classifies the peasant households into 4 types, which are pure agriculture type, agriculture-dependent type, non-farming-dependent type and non-agriculture type. With above classification, the analysis is carried out on different types of households’ livelihood strategies and land use patterns, in terms of the number of land plots, the area of land, the renting of land, the arrangement of labor forces and the yield-increasing input and so on. Through contrastive study on different types of households’ perceptions and strategies of livelihood improving, this paper analyzes their influences on land use and comes up with the suggestions including properly utilizing land resources as well as improving household livelihood capability and level. The results show that different types of households reflect different characteristics in their family scale, family member, labor allocation, age structure and cultural level. To be specific, for the households of agriculture-dependent type and non-farming-dependent type, their livelihood strategy combination is better and livelihood diversity index is higher, and hence they possess relatively lower livelihood risks. Different households’ land use patterns are obviously different. From the angle of the area of land, land area per household and per capita, it can be summarized as the sequence of agriculture-dependent type>pure agriculture type>non-farming-dependent type>non-agriculture type. Among these, the households of agriculture-dependent type possess the largest renting

  18. Implication of drainage basin parameters of a tropical river basin of South India

    Science.gov (United States)

    Babu, K. J.; Sreekumar, S.; Aslam, Arish

    2016-03-01

    Drainage morphometry provides quantitative description of the drainage system which is an important aspect of the characterisation of watersheds. Chalakudi River is one of the important rivers of the South India which has attracted attention of many environmental scientists recently because of the proposed Athirapally Hydel Project across the river. SRTM (Shuttle Radar Topographic Mission) data were used for preparing DEM (Digital Elevation Model), Aspect Map and Slope Map. Geographical Information System (GIS) was used for the evaluation of linear, areal and relief aspects of morphometric parameters. The study reveals that the terrain exhibits dentritic and trellis pattern of drainage. The Chalakudi River Basin has a total area of 1,448.73 km2 and is designated as seventh-order basin. The drainage density of the basin is estimated as 2.54 and the lower-order streams mostly dominate the basin. The high basin relief indicates high runoff and sediment transport. The elongation ratio of the Chalakudi Basin is estimated as 0.48 and indicates that the shape of the basin is elongated. The development of stream segments in the basin area is more or less effected by rainfall. Relief ratio indicates that the discharge capability of watershed is very high and the groundwater potential is meagre. The low value of drainage density in spite of mountainous relief indicates that the area is covered by dense vegetation and resistant rocks permeated by fractures and joints. These studies are helpful in watershed development planning and wise utilization of natural resources.

  19. Cenozoic crustal shortening and thickening contributions to Andean orogenesis: Preliminary results from structural mapping in the southern Peruvian Andes

    Science.gov (United States)

    Perez, N.; Horton, B. K.

    2012-12-01

    Estimates of Cenozoic crustal shortening and thickening from the southern Peruvian Andes are necessary to address ongoing debates regarding growth of the Andes and Altiplano plateau. However, limited regional studies in southern Peru prevent accurate assessments of the structural contributions to high topography. This study provides new structural mapping along a >200 km transect spanning the northernmost Altiplano to Subandes at 13-15.5°S and fills the gap between existing central Peruvian and northern Bolivian studies. New stratigraphic data, fault relationships and fold orientations are used to create an updated geologic map and provide insights into the style, timing and magnitude of crustal deformation. Preliminary cross sections accompanying these map transects illustrate deformation style and provide first-order estimates of shortening. Further cross section analyses will be balanced and provide estimates of total crustal shortening and associated thickening in southern Peru. The study transect is subdivided into belts according to the age of exposed rocks and style of deformation. From west to east these belts include: Cretaceous strata dominated by tight folds, closely spaced faults and multiple detachments; Permo-Triassic strata dominated by thicker thrust sheets and fault-fold orientations departing from typical Andean trends; and Paleozoic rocks characterized by thick thrust sheets and deformation focused near major faults. The Cretaceous belt is composed of marine limestones and upward coarsening, siltstone to coarse sandstone progradational sequences. Disharmonic and detachment folds in the Cretaceous section demonstrate the importance of interbedded gypsum and mudstone layers. Fault relationships suggest local shortening during the Early Cretaceous. The Permo-Triassic belt is composed of thick Permian carbonates (Copacabana Formation) and interbedded sandstones, conglomerates and volcanics of the Mitu Formation. This study defines the orientation of

  20. Spatial and temporal patterns of crop yield and marginal land in the Aral Sea Basin: derivation by combining multi-scale and multi-temporal remote sensing data with alight use efficiency model

    OpenAIRE

    Fritsch, Sebastian

    2013-01-01

    Irrigated agriculture in the Khorezm region in the arid inner Aral Sea Basin faces enormous challenges due to a legacy of cotton monoculture and non-sustainable water use. Regional crop growth monitoring and yield estimation continuously gain in importance, especially with regard to climate change and food security issues. Remote sensing is the ideal tool for regional-scale analysis, especially in regions where ground-truth data collection is difficult and data availability is scarce. New sat...

  1. Patterns of species richness and composition of fish assemblages in streams of the Ivinhema River basin, Upper Paraná River Padrões de riqueza e composição de espécies das assembleias de peixes em riachos da bacia do rio Ivinhema, Alto Rio Paraná

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    Yzel Rondon Súarez

    2011-06-01

    Full Text Available AIM: The present study analyzed the spatial variation in fish species richness and composition in streams of the Ivinhema River basin, Upper Paraná basin, determining the relationship between local and regional descriptors of the fish assemblage organization; METHOD: From 2001 to 2011 we sampled 200 stream stretches, using different sampling methods. Local species richness and composition were analyzed using univariate and multivariate methods to detect patterns of variation in the fish assemblage organization; RESULTS: We identified 111 fish species in the streams, and estimated the occurrence of 117 fish species (CIα0.05 = 111 to 123 with lower species richness in headwater streams compared to the lower parts of the basin. The fish species recorded were predominantly of small size, and the mean size increased from the headwaters to the river mouth. The four most common species are widely distributed in the basin. However, 24 species are allocthonous to the Upper Paraná basin, and two species (Chaetobranchopsis australis and Apistogramma commbrae are recorded here for the first time in the Upper Paraná basin. Altitude was the main determinant of local fish species richness and composition, and a discontinuity in assemblage organization (richness, composition, fish size was detected at approximately 430 m a.s.l.; CONCLUSION: Streams of the Ivinhema River basin are inhabited mainly by small-sized fishes; and longitudinal variation, interacting with local characteristics, determines the fish assemblage patterns.OBJETIVOS: O presente estudo tem como objetivo analisar a variação especial na riqueza e composição de espécies de peixes em riachos da bacia do rio Ivinhema, Alto Rio Paraná determinando a relação entre características locais e regionais na organização das assembleias de peixes; MÉTODOS: Amostramos 200 trechos de riachos entre 2001 e 2011 utilizando diferentes petrecho de pesca. A riqueza local e composição de esp

  2. Monitoring water level in large trans-boundary ungauged basins with altimetry: the example of ENVISAT over the Amazon basin

    Science.gov (United States)

    Seyler, Frederique; Calmant, Stephane; da Silva, Joecila; Filizola, Naziano; Roux, Emmanuel; Cochonneau, Gerard; Vauchel, Philippe; Bonnet, Marie-Paule

    2009-01-01

    Brasil and Bolivia have water plans projects on the Beni-Madeira river, a major tributary of the Amazon. There are four main tributaries to the Rio Madeira: the Guapore, the Mamore and the Beni rivers into the Bolivian territory, and the Madre de Dios River crossing the North of Bolivia, coming from Peru. Most parts of these rivers are very far from the Andean capital cities of Bolivia and Peru, unreachable for long periods of time. Very few gauging stations are in operation, either for the Bolivian or the Peruvian part, most of them being located at the Andes piedmont or near the confluence at the Brazilian border as they form the Madeira river. This situation is exemplary of large transboundary basins in the tropical part of the world. We have computed 39 water level time series using ENVISAT altimetry data over the four tributaries of the Madeira and the Madeira itself. We present a preliminary study mostly conducted onto the Guapore river, in order to assess the quality of these time series for a variety of situations, but mostly narrow and meandering riverbeds. Comparison between water levels variation in the mainstream and within the inundations plains and lakes are drawn. We conclude by the perspectives offered by the combined use of radar altimetry and SAR imagery for the global monitoring of water resources, in large tropical transboundary basins.

  3. Oroclinal bending and orogenic asymmetry? A case study from the apex of the Northern Andean orocline

    Science.gov (United States)

    Mora, A.; Parra-Amezquita, M.; Rodriguez, G.

    2013-05-01

    Here we present new thermocronometric analysis from the eastern flank of the Colombian Eastern Cordillera at 7° N lat. which aid in deconvolving the roles of plate tectonics, tectonic inheritance and surface processes in building the Cocuy syntaxis, at the apex of the Northern Andean orocline. The Cocuy syntaxis is the region with higher structural and topographic relief in the Eastern Cordillera. The primary factor controlling that is faster tectonism, apparently related with the most important Panama collision at ca. 4 Ma. This push from behind is focused between two resistant plates and escapes toward a weak foreland plate, which is able to flex. However, we suggest it is an enhanced late Miocene to Recent exhumation episode which is responsible for the limited advance of the deformation front as basement involved blocks. Faster denudation causes faster sedimentation rates in the weak foreland plate east of Cocuy. In this case, the thick pile of synkinematic sediments would make an otherwise possible thin skin deformation migration very difficult.

  4. Geographic determinants of gene flow in two sister species of tropical Andean frogs.

    Science.gov (United States)

    Guarnizo, Carlos E; Cannatella, David C

    2014-01-01

    Complex interactions between topographic heterogeneity, climatic and environmental gradients, and thermal niche conservatism are commonly assumed to indicate the degree of biotic diversification in montane regions. Our aim was to investigate factors that disrupt gene flow between populations and to determine if there is evidence of downslope asymmetric migration in highland frogs with wide elevational ranges and thermal niches. We determined the role of putative impediments to gene flow (as measured by least-cost path (LCP) distances, topographic complexity, and elevational range) in promoting genetic divergence between populations of 2 tropical Andean frog sister species (Dendropsophus luddeckei, N = 114; Dendropsophus labialis, N = 74) using causal modeling and multiple matrix regression. Although the effect of geographic features was species specific, elevational range and LCP distances had the strongest effect on gene flow, with mean effect sizes (Mantel r and regression coefficients β), between 5 and 10 times greater than topographic complexity. Even though causal modeling and multiple matrix regression produced congruent results, the latter provided more information on the contribution of each geographic variable. We found moderate support for downslope migration. We conclude that the climatic heterogeneity of the landscape, the elevational distance between populations, and the inability to colonize suboptimal habitats due to thermal niche conservatism influence the magnitude of gene flow. Asymmetric migration, however, seems to be influenced by life history traits. PMID:24336965

  5. Cliffs used as communal roosts by Andean condors protect the birds from weather and predators.

    Directory of Open Access Journals (Sweden)

    Sergio A Lambertucci

    Full Text Available The quality and availability of resources influence the geographical distribution of species. Social species need safe places to rest, meet, exchange information and obtain thermoregulatory benefits, but those places may also serve other important functions that have been overlooked in research. We use a large soaring bird that roosts communally in cliffs, the Andean condor (Vultur gryphus, as a model species to elucidate whether roost locations serve as a refuge from adverse weather conditions (climatic refuge hypothesis, CRH, and/or from predators or anthropogenic disturbances (threats refuge hypothesis, TRH. The CRH predicts that communal roosts will face in the opposite direction from where storms originate, and will be located in climatically stable, low precipitation areas. The TRH predicts that communal roosts will be large, poorly accessible cliffs, located far from human-made constructions. We surveyed cliffs used as communal roosts by condors in northwestern Patagonia, and compared them with alternative non-roosting cliffs to test these predictions at local and regional scales. We conclude that communal roosting places provide refuge against climate and disturbances such as, for instance, the threats of predators (including humans. Thus, it is not only the benefits gained from being aggregated per se, but the characteristics of the place selected for roosting that may both be essential for the survival of the species. This should be considered in management and conservation plans given the current scenario of global climate change and the increase in environmental disturbances.

  6. Insects associated with exposed decomposing bodies in the Colombian Andean Coffee Region

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    Diana Grisales

    2010-01-01

    Full Text Available In Colombia, mainly classic forensic medicine methods were used to clarify crimes until 2004. However, other disciplines, including forensic entomology, started to be considered only after the New Accusatory System introduction in Bogotá and the Coffee Region in 2005. In order to provide tools for obtaining evidentiary material elements in judicial trials, it is presented here the succession of insects throughout the decomposition process of an exposed carcass of Sus scrofa Linnaeus 1758 (Suidae and the Occurrence Matrix of colonizing species. This process was evaluated under ambient conditions in the Andean rural area of the city of Pereira, in the Mundo Nuevo district, located in a pre-montane Wet Forest area, from October to November 2006. A sampling period of 27 days and 3198 individuals were collected. We found these colonizing species in the following stages of decomposition: Lucilia eximia (Wiedemann, 1819 fresh; Hemilucilia semidiaphana (Rondani, 1850, Oxelytrum discicolle (Brullé, 1840, and Cochliomyia macellaria (Fabricius 1775 bloated; Chrysomya albiceps (Wiedemann 1819, Compsomyiops verena (Walker, 1849, Ophyra aenescens (Wiedemann, 1830 and Musca domestica Linnaeus, 1758 active; Fannia sp. advanced and Stearibia nigriceps (Meigen, 1826 remains. This study provides support tools to define the Post Mortem Interval that may be used by experts from government institutions and laboratories officially accredited.

  7. Microsatellite isolation and characterization for Colletotrichum spp, causal agent of anthracnose in Andean blackberry.

    Science.gov (United States)

    Marulanda, M L; López, A M; Isaza, L; López, P

    2014-01-01

    The genus Colletotrichum, comprised of pathogenic fungi that affect plants grown worldwide, causes the disease known as anthracnose in several fruit and vegetable species. Several studies conducted on plants have shown that the disease is characterized by the presence of one or several species of the fungus attacking the fruit or other organs of the same host. To develop and implement effective control strategies, it is vital to understand the genetic structure of the fungus in agricultural systems, identify associated Colletotrichum species, and define the subpopulations responsible for the disease. Molecular tools were accordingly developed to characterize genotypic populations of Colletotrichum spp, causal agent of anthracnose in commercial crops of Andean blackberry (Rubus glaucus Benth.). A microsatellite-enriched library for Colletotrichum gloeosporioides was developed to identify and characterize microsatellite loci among isolates collected in R. glaucus plantations. Thirty microsatellites were developed and tested in 36 isolates gathered from eight different blackberry-production areas of Colombia. Ten pairs of microsatellites were polymorphic. PMID:25299081

  8. Vicuña conservation and poverty alleviation? Andean communities and international fibre markets

    Directory of Open Access Journals (Sweden)

    Gabriela Lichtenstein

    2009-09-01

    Full Text Available Vicuna (Vicugna vicugna fiber is produced by extremely low-income communities that inhabit the harsh environment of the Andes in Argentina, Chile, Peru and Bolivia. At the other end of the social scale, affluent consumers are willing to pay high prices for vicuna-made accessories and clothes. Vicuna management projects follow the logic of community-based wildlife management. The rationale for seeking to conserve vicuñas through sustainable use is that commercial utilization of the fiber (obtained from live-shorn animals will generate sufficient economic benefits to outweigh the costs of conservation, and contribute to community development and poverty alleviation. However, although conservation efforts have been extremely successful with vicuñas having recovered from the brink of extinction, the socio-economic achievements have thus far proved modest. This paper explores multiple-objective projects that address vicuña conservation and poverty alleviation in Andean countries. In doing so it analyses the tensions that exist between these objectives, as well as the factors that limit a more equitable distribution of benefits among stakeholders. Examples are drawn from vicuna management under common-property in Peru and Bolivia, and vicuna captive management under private property in Argentina. These case studies enable us to illustrate the complex relationship between local communities and the global market, and the importance of community enterprises and supportive government policy in managing a common pool resource.

  9. Gut Microbiome of an 11th Century A.D. Pre-Columbian Andean Mummy.

    Directory of Open Access Journals (Sweden)

    Tasha M Santiago-Rodriguez

    Full Text Available The process of natural mummification is a rare and unique process from which little is known about the resulting microbial community structure. In the present study, we characterized the microbiome of paleofeces, and ascending, transverse and descending colon of an 11th century A.D. pre-Columbian Andean mummy by 16S rRNA gene high-throughput sequencing and metagenomics. Firmicutes were the most abundant bacterial group, with Clostridium spp. comprising up to 96.2% of the mummified gut, while Turicibacter spp. represented 89.2% of the bacteria identified in the paleofeces. Microbiome profile of the paleofeces was unique when compared to previously characterized coprolites that did not undergo natural mummification. We identified DNA sequences homologous to Clostridium botulinum, Trypanosoma cruzi and human papillomaviruses (HPVs. Unexpectedly, putative antibiotic-resistance genes including beta-lactamases, penicillin-binding proteins, resistance to fosfomycin, chloramphenicol, aminoglycosides, macrolides, sulfa, quinolones, tetracycline and vancomycin, and multi-drug transporters, were also identified. The presence of putative antibiotic-resistance genes suggests that resistance may not necessarily be associated with a selective pressure of antibiotics or contact with European cultures. Identification of pathogens and antibiotic-resistance genes in ancient human specimens will aid in the understanding of the evolution of pathogens as a way to treat and prevent diseases caused by bacteria, microbial eukaryotes and viruses.

  10. Investigation Into the Humaneness of Slaughter Methods for Guinea Pigs (Cavia porcelus) in the Andean Region.

    Science.gov (United States)

    Limon, Georgina; Gonzales-Gustavson, Eloy A; Gibson, Troy J

    2016-01-01

    Guinea pigs (Cavia porcelus) are an important source of nonhuman animal protein in the Andean region of South America. Specific guidelines regarding the welfare of guinea pigs before and during slaughter have yet to be developed. This study critically assessed the humaneness of 4 different stunning/slaughter methods for guinea pigs: cervical neck dislocation (n = 60), electrical head-only stunning (n = 83), carbon dioxide (CO2) stunning (n = 21), and penetrating captive bolt (n = 10). Following cervical neck dislocation, 97% of guinea pigs had at least 1 behavioral or cranial/spinal response. Six percent of guinea pigs were classified as mis-stunned after electrical stunning, and 1% were classified as mis-stunned after captive bolt. Increased respiratory effort was observed during CO2 stunning. Apart from this finding, there were no other obvious behavioral responses that could be associated with suffering. Of the methods assessed, captive bolt was deemed the most humane, effective, and practical method of stunning guinea pigs. Cervical neck dislocation should not be recommended as a slaughter method for guinea pigs. PMID:26963642

  11. Revisiting the Andean butterfly Eryphanis zolvizora group (Lepidoptera, Nymphalidae: one or several species?

    Directory of Open Access Journals (Sweden)

    Patrick Blandin

    2014-01-01

    Full Text Available Eryphanis zolvizora (Hewitson, 1877 is a rare Andean endemic butterfly, described from Bolivia, which has been historically classified either as a unique species, or as part of a group of three allopatric species from Bolivia, Ecuador and Colombia. In this paper, the group is revised using more than 200 specimens housed in 34 European, and North and South American public and private collections. For the first time, the presence of the group in Western Ecuador and Venezuela is confirmed, and important data on Peruvian populations are provided. In some populations, individual variations of genitalia are observed. Nevertheless, male genitalia allow the distinction of four geographical groups. Considering also habitus characters, eight taxa are distinguished and considered to be subspecies, of which five are new: Eryphanis zolvizora inca ssp. nov., Eryphanis zolvizora chachapoya ssp. nov., Eryphanis zolvizora casagrande ssp. nov.., Eryphanis zolvizora reyi ssp. nov., and Eryphanis zolvizora isabelae ssp. nov.  In the present state of knowledge, these taxa are allopatric, except for a possible geographic overlap in central Peru, where data are insufficient to prove sympatry. The “several subspecies vs. several species” dilemma is discussed, considering its impact for conservation action and policies.

  12. Karyotypic variation in the Andean rodent Phyllotis xanthopygus (Waterhouse, 1837 (Rodentia, Cricetidae, Sigmodontinae

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    Carolina Alicia Labaroni

    2014-12-01

    Full Text Available Phyllotis xanthopygus (Waterhouse, 1837 is an Andean rodent endemic to South America. Despite its wide geographical distribution in Argentina, few individuals have been studied on the cytogenetic level and only through conventional staining. In this work, chromosome characterization of Argentine samples of this species was performed using solid staining, C-banding and base-specific fluorochromes. Twenty two specimens were analyzed, collected in the provinces of Jujuy, Catamarca, and the north and south of Mendoza. All studied specimens showed 2n=38, having mostly the bi-armed autosomes, metacentric or submetacentric. Fundamental Number varied between 70 and 72. These changes were due to the presence of chromosome heteromorphisms in individuals from southern Mendoza and Jujuy. C-banding revealed pericentromeric blocks of constitutive heterochromatin in most chromosomes. Acrocentric chromosomes involved in heteromorphisms showed high variation in the amount of heterochromatin within and among populations. Additionally, banding with fluorochromes (DAPI and chromomycin A3 revealed homologous localization of AT and GC rich regions among chromosomes of the different populations analyzed. Comparisons among heteromorphic pairs suggested, however, that the variation might be the result of complex chromosome rearrangements, involving possibly amplifications and/or deletions of heterochromatic segments. These results are in accordance with molecular studies that indicate genetic variability within and among the populations of this taxon.

  13. Phytosynthesis of gold nanoparticles using Andean Ajı′ (Capsicum baccatum L.

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    Brajesh Kumar

    2015-12-01

    Full Text Available This article covers the importance of Andean Ajı′/Chilli (Capsicum baccatum L. mediated synthesis of gold nanoparticles (AuNPs, which favors for green chemistry and escape us from the use of hazardous chemicals. UV–visible spectroscopy was used to monitor the quantitative formation of AuNPs. Further, as synthesized AuNPs were characterized using Transmission electron microscopy, Dynamic Light Scattering, and X-ray diffraction. It produced spherical AuNPs at λmax = 540 nm of average size 23.9 ± 9.7 nm without any aggregation. Ajı′ extract (aq was the good reducing and capping agent in terms of conversion to Au3+ to AuNPs. The synthesized AuNPs, also enhancing the photocatalytic degradation of methylene blue (>50%, k = 1.9585 × 10−3 min−1 under direct solar light irradiation. In addition, the experimental approach is benign, ecofriendly, and inexpensive for industrial-scale production of nanoparticles using Aji extract as natural bioreductant.

  14. Hydrophilic antioxidants from Andean tomato landraces assessed by their bioactivities in vitro and in vivo.

    Science.gov (United States)

    Di Paola Naranjo, Romina D; Otaiza, Santiago; Saragusti, Alejandra C; Baroni, Veronica; Carranza, Andrea Del V; Peralta, Iris E; Valle, Estela M; Carrari, Fernando; Asis, Ramón

    2016-09-01

    Potential nutraceutical properties of hydrophilic antioxidants in fruits of tomato landraces collected in Andean valleys were characterised. Antioxidant metabolites were measured by HPLC-DAD-MS/MS in mature fruits and their biological activities were assessed by in vitro and in vivo methods. In vitro antioxidant capacities were established by TEAC and FRAP methods. For in vivo biological activities we used a procedure based on Caenorhabditis elegans subjected to thermal stress. In addition, Saccharomyces cerevisiae was also used as a rapid screening system to evaluate tomato antioxidant capacity. All tomato accessions displayed significant differences regarding metabolic composition, biological activity and antioxidant capacity. Metabolite composition was associated with geographical origin and fruit size. Antioxidant activities showed significant association with phenolic compounds, such as caffeoylquinic acids, ferulic acid-O-hexosides and rutin. Combination of in vitro and in vivo methods applied here allowed evaluation of the variability in nutraceutical properties of tomato landraces, which could be applied to other fruits or food products. PMID:27041310

  15. Ultrasound as pretreatment to convective drying of Andean blackberry (Rubus glaucus Benth).

    Science.gov (United States)

    Romero J, Carlos A; Yépez V, Byron D

    2015-01-01

    In this study, we evaluated the use of ultrasound as a pretreatment for convective drying of Andean blackberry (Rubus glaucus Benth). For this, a Box-Behnken experimental design was used to study the effect of ultrasound vibration amplitude (0-90μm), time of sonication (10-30min) and air temperature (40-60°C) on the retention of antioxidant compounds and on the kinetics of convective drying. The results showed that the antioxidant activity on fruit was reduced as the vibration amplitude and time of sonication increased, while was found that vibration amplitude ultrasound and air drying temperature were the variables that more affect the drying rate of blackberries. The drying rate increased by almost five times when samples were treated with ultrasound at 90μm for 20min. They were then dried using air at 60°C. It is concluded that the application of ultrasound in blackberry processing allows to obtain a dehydrated product with better functional quality and shows to be effective in reducing the time necessary to achieve a given value of moisture during convective drying. PMID:25023827

  16. Receiver functions and crustal structure of the northwestern Andean region, Colombia

    Science.gov (United States)

    Poveda, Esteban; Monsalve, Gaspar; Vargas, Carlos Alberto

    2015-04-01

    We used the receiver function technique to deduce crustal thickness beneath the northwestern Andean system, using data from the permanent seismic network of Colombia, combined with some of the IRIS and CTBTO stations in Colombia and Ecuador. The estimation of crustal thickness was made using the primary P to s conversion and crustal reverberations. The bulk crustal VP/VS ratio was constrained using a crustal thickness versus VP/VS stacking method, in addition to estimations using a time to depth conversion technique based on results of a modified Wadati diagram analysis. We observed a wide range of crustal thicknesses, including values around 17 km beneath the Malpelo Island on the Pacific Ocean, 20 to 30 km at the coastal Pacific and Caribbean plains of Colombia, 25 to 40 km beneath the eastern plains and foothills, 35 km beneath the Western Cordillera, 45 km at the Magdalena River intermountain valley, 52 to 58 km under the northern Central Cordillera, and reaching almost 60 km beneath some of the volcanoes of the Southern Cordilleran system of Colombia; crustal thickness can be slightly greater than 60 km beneath the plateau of the Eastern Cordillera. The values of VP/VS are particularly high for some of the stations on the volcanic centers, reaching values above 1.79, probably related to the addition of mafic materials to the lower crust, and in the plateau of the Eastern Cordillera near Bogota, where we speculate about the possibility of crustal seismic anisotropy associated with shear zones.

  17. Response Analysis of eight native species of high Andean forest with two methods of propagation

    International Nuclear Information System (INIS)

    The objective of this research was to generate information on the native tree species represent an alternative in the ecological restoration of the Colombian high Andean forests, according to its dynamo-genetic characteristics. We have chosen and spread the species: Baccharis latifolia (R and P), Bocconia frutescens L., Cordia cylindrostachya (R and P), Diplostephium rosmarinifolium (Benth), Drymis granadensis L f., Eupatorium angustifolium (Kunth), Palicourea vaginata Benth, and Palicourea linearifolia Wernham. The species include a morphological description of flowers, fruits and seeds, and ISTA tests. The spread experiments were made in the nurseries of the Universidad Distrital and La Florida park. For the sexual spread, we have used as treatments four gibberellins concentrations and three shadow conditions, while the vegetative spread consisted of two diameters and ive indol butiric acid (IBA) concentrations. Results have shown that pre-germination treatments are needed for Bocconia frutescens y Palicourea vaginata, in order to increase the probability and germination rate. On the other hand, shadow conditions are needed for Baccharis latifolia, Diplostephium rosmarinifolium, Drymis granadensis, Eupatorium angustifolium and Palicourea vaginata, as their seeds exhibit photoblastic characteristics. Due to the Cordia cylindrostachya and Palicourea linearifolia seed attack by insects (Lepidoptera and Hymenoptera) their sexual spread is highly limited. Finally, regarding the species response to the IBA and diameter combinations, each species responded in a different manner. Additionally, regarding the vegetative spread, the species Bocconia frutescens, Cordia cylindrostachya, Palicourea vaginata, Diplostephium rosmarinifolium and Drymis granadensis were very difficult to spread

  18. [Floristic composition and distribution of the Andean subtropical riparian forests of Lules River, Tucuman, Argentina].

    Science.gov (United States)

    Sirombra, Martín G; Mesa, Leticia M

    2010-03-01

    We studied the floristic composition and distribution of the riparian forest of two hydrographical systems in a subtropical Andean region. Using uni and multivariate techniques, we tested the hypotheses that a differentiable riparian forest exists, composed by native vegetation typical of the Yungas phytogeographical province, and that the distribution of vegetation varied significantly with geomorphologic characteristics. Parallel transects along the water courses were used to collect presence-absence data of vegetation in eleven sites. Detrended Correspondence Analysis defined a group of common riparian species for the studied area (Solanum riparium, Phenax laevigatus, Tipuana tipu, Cestrum parqui, Carica quercifolia, Acacia macracantha, Celtis iguanaea, Juglans australis, Pisoniella arborescens, Baccharis salicifolia, Cinnamomum porphyrium and Eugenia uniflora) and identified two reference sites. The distribution of the riparian vegetation varied significantly with the geomorphic characteristics along the studied sites. Riparian habitats were composed by native and exotic species. A distinct riparian flora, different in structure and function from adjacent terrestrial vegetation, could not be identified. Riparian species were similar to the adjacent terrestrial strata. These species would not be limited by the proximity to the river. Anthropogenic impacts were important factors regulating the introduction and increase of exotic vegetation. The lack of regulation of some activities in the zone could cause serious problems in the integrity of this ecosystem. PMID:20411737

  19. Rise of the central Andean coast by earthquakes straddling the Moho

    Science.gov (United States)

    Melnick, Daniel

    2016-05-01

    Surface movements during the largest subduction zone earthquakes commonly drown coastlines. Yet, on geological timescales, coastlines above subduction zones uplift. Here I use a morphometric analysis combined with a numerical model of landscape evolution to estimate uplift rates along the central Andean rasa--a low-relief coastal surface bounded by a steep cliff formed by wave erosion. I find that the rasa has experienced steady uplift of 0.13 +/- 0.04 mm per year along a stretch of more than 2,000 km in length, during the Quaternary. These long-term uplift rates do not correlate with Global Positioning System (GPS) measurements of interseismic movements over the decadal scale, which implies that permanent uplift is not predominantly accumulated during the interseismic period. Instead, the rate of rasa uplift correlates with slip during earthquakes straddling the crust-mantle transition, the Moho. Such deeper earthquakes with magnitude 7 to 8 that occurred between 1995 and 2012 resulted in decimetres of coastal uplift. Slip during these earthquakes is located below the locked portion of the plate interface, and therefore may translate into permanent deformation of the overlying plate, where it causes uplift of the coastline. Thus, lower parts of the plate boundary are stably segmented over hundreds to millions of years. I suggest the coastline marks the surface expression of the transition between the shallow, locked seismogenic domain and the deeper, conditionally stable domain where modest earthquakes build up topography.

  20. Plant functional groups of potential restoration use in advancing edges of high Andean forests

    International Nuclear Information System (INIS)

    The study of plant functional groups constitutes a useful tool in the identification of ecological characteristics relevant in community regeneration. The aim of this study was to identify plant's functional groups in high Andean forest advance edges and to evaluate their role during secondary succession in abandoned pasture lands. Based on 10 x 10 m vegetation relevees for the shrubby-arboreal stratum and 1 x 1 m plots for the herbaceous stratum and the revision of vital attributes for each of the species found, this study uses a multivariate approach to construct a trait-based emergent group's classification. The most important attributes in the definition of the groups were the dispersion mechanism and the presence of basal trunk ramification in woody species; in addition differences in the presence of vegetative propagation, specific leaf area index and the ratio height/diameter at breast height were found between groups of the shrubby-arboreal stratum. Four distinct groups were defined in the herbaceous layer and five in the shrubby-arboreal layer, each group contains species with similar colonization strategies. Among the defined groups, the herbaceous species dispersed by various abiotic factors, the shrubby species with basal ramification and dispersed by wind and the species dispersed by birds constitute key strategies in forest recovery in adjacent abandoned pasture lands dominated by Holcus lanatus, and facilitate the establishment of secondary forest species.

  1. Facies architecture of heterolithic tidal deposits : The Holocene Holland Tidal Basin

    OpenAIRE

    Donselaar, M.E.; Geel, C.R.

    2007-01-01

    The size, shape and spatial position of lithofacies types (or facies architecture) in a tidal estuarine basin are complex and therefore difficult to model. The tidal currents in the basin concentrate sand-sized sediment in a branching pattern of tidal channels and fringing tidal flats. Away from the sandy tidal flats the sediment gradually changes to mud-dominated heterolithic deposits and clay. In this paper the facies analysis of a tidal estuarine basin, the Holocene Holland Tidal Basin (HH...

  2. Fish fauna in Iberian Mediterranean river basins: biodiversity, introduced species and damming impacts

    OpenAIRE

    Clavero, Miguel; Blanco-Garrido, F.; Prenda, J.

    2004-01-01

    1. A basin approximation was used to analyse distribution patterns of different components of biodiversity (taxonomic richness, endemicity, taxonomic singularity, rarity) and conservation status of freshwater fish fauna in 27 Mediterranean Iberian rivers. 2. Basin area alone explained more than 80% of variation in native species richness. Larger basins featured not only a higher number of native species, but also more endemic and rare species and fewer diversified genera than smaller basins. ...

  3. Spatial patterns of phytoplanktonic pigments and primary production in a semi-enclosed periantarctic ecosystem: the Strait of Magellan

    Science.gov (United States)

    Saggiomo, V.; Goffart, A.; Carrada, G. C.; Hecq, J. H.

    1994-07-01

    The spatial patterns of nitrate, phytoplankton size-fractionated chlorophyll a, photosynthetic pigments detected by HPLC and primary production were studied at the end of the austral summer (February-March 1991), in the Strait of Magellan to provide insight into the mechanisms governing this seemi-enclosed periantartic ecosystem. Climatological peculiarities, hydrodynamic constraints, runoff and land forcing were considered. The most important features identified for this area were the confinement of the microphytoplankton fraction to the external parts of the Strait and the rather uniform dimensional structure of the phytoplankton communities (plant pigments detected by HPLC, nitrate and primary production showed an uneven but similar distribution, allowing for the characterization of different sectors within the Strait, according to different types and intensities of forcing factors. The different ecological sectors identified along the Strait were associated with distinct hydrographic typologies: an oligotrophic, wind-mixed coastal area, adjacent to the Pacific opening; a high runoff fjord and a divergence zone in the Andean sectors; a stratified inland sea in the basin-like part of the channel (Paso Ancho) and a shallow, tidally mixed system in the Patagonian sectors. Areas of relatively low and high phytoplankton biomass and primary production alternate along the Strait, according to the hydrographic structures of the different sectors. Phytoplankton biomass, in terms of active Chl. a (spectrofluorometric determination) ranged between 10 and 51 mg m -2 and primary production between 275 and 1170 mg C m -2 d -1. The assemblage of plant pigments detected by HPLC indicated that the high levels of phytoplankton pigments and production were most likely attributable to Chlorophytes, Prasinophytes, Prymnesiophytes and/or Gyrodinium and Gymnodinium-like Dinoflagellates that were submitted to natural senescence and to superfluous feeding activity; while, when Diatoms

  4. Temperatura de la superficie terrestre en diferentes tipos de cobertura de la región andina colombiana / Land surface temperature in different land covers of the Andean Region of Colombia

    OpenAIRE

    Andrés Felipe Carvajal; José Daniel Pabón

    2014-01-01

    This study assessed the relationship of Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) with land surface temperature (LST), using Landsat images of La Vieja river watershed, in the Andean region of Colombia. We evaluated land covered by Andean forest, forest plantation, coffee, pasture and urban area. Negative correlations between indices and LST were identified, and significant differences (p

  5. Petrology and oxygen isotope geochemistry of the Pucon ignimbrite - Southern Andean volcanic zone, Chile: Implications for genesis of mafic ignimbrites

    International Nuclear Information System (INIS)

    Although mafic components of dominantly intermediate to silicic ignimbrites are rather common, voluminous, dominantly mafic ignimbrites are rare (e.g., Smith, 1979; cf. Freundt and Schmincke, 1995). Volcan Villarrica, the most active composite volcano in South America, located in the Southern Andean Volcanic Zone (SAVZ, Lopez-Escobar and Moreno, 1994a), has produced two such ignimbrites, respectively the Lican and Pucon Ignimbrites, in the last 14,000 years (Clavero, 1996). The two ignimbrites are low-Si andesite and basaltic-andesite to low-Si andesite, respectively, the former about twice as voluminous as the later (10 and 5 km3). Eruption of the ignimbrites produced calderas respectively 5 and 2 km in diameter (Moreno, 1995; Clavero, 1996). In addition to its mafic bulk composition, the Pucon Ignimbrite (PI) is also distinguished by numerous xenolithic fragments among and also within magmatic pyroclasts. Many of these are fragments of granitoid rocks. Volcan Villarrica has also produced numerous smaller mafic ignimbrites and pyroclastic surge deposits, as well as dominantly basaltic fallout and lava flows (Lopez-Escobar and Moreno, 1994; Moreno, 1995; Clavero, 1996; Hickey-Vargas et al., 1989; Tormey et al., 1991). Reasons for the unusual style of mafic explosive activity at Volcan Villarrica are unclear. Clavero (1996), based upon an exemplary thesis-study of the physical volcanology and petrology of the PI, suggests it formed in response to a sequence of events beginning with injection of a shallow basaltic andesite magma chamber by hotter basaltic magma. In his model mixing and heat transfer between the two magmas initiated a violent Strombolian eruption that destabilized the chamber causing infiltration of large amounts of meteoric-water saturated country rocks. The Pucon Ignimbrite formed in response to subsequent phreatomagmatic interactions. In contrast, Lopez-Escobar and Moreno (1994) infer on geochemical grounds that volatiles leading to the explosive

  6. Basins of attraction for chimera states

    Science.gov (United States)

    Martens, Erik A.; Panaggio, Mark J.; Abrams, Daniel M.

    2016-02-01

    Chimera states—curious symmetry-broken states in systems of identical coupled oscillators—typically occur only for certain initial conditions. Here we analyze their basins of attraction in a simple system comprised of two populations. Using perturbative analysis and numerical simulation we evaluate asymptotic states and associated destination maps, and demonstrate that basins form a complex twisting structure in phase space. Understanding the basins’ precise nature may help in the development of control methods to switch between chimera patterns, with possible technological and neural system applications.

  7. Valuation of forest ecological benefit and distributing pattern in Shiyang River Basin Based on GIS%基于GIS的石羊河流域森林生态效益估算与空间分布特征研究

    Institute of Scientific and Technical Information of China (English)

    赵军; 陈姗

    2011-01-01

    The Shiyang River basin is one of important river basins in arid region of Northwest China. But because of the over-utilization of water resources and irrational water allocation, vegetation degradation and desertification issue in the lower reaches are very serious. So the river regulation and the protection of ecological environment are extremely urgent. In view of the serious ecological environment problem, this paper takes advantage of the technique of GIS and the method of data spatialization, obtains the mean precipitation raster layers of Shiyang River basin by Kriging interpolation. And based on Shiyang River basin forest types raster data, and in combination with relevant statistical information, then by using ArcGIS Grid computing and clustering approach, generates ecological benefit distribution maps which is about the conservation of water resources, about the value of soil conservation,the value of CO2 fixation and O2 production and so on. Based on these data and synthesizing every raster layer, we get the forest ecological benefit volume distribution map in Shiyang River basin, to give a visual interpretation of spatial distribution condition of research district forest ecological benefit. The result shows that: the service valuation of forest ecosystem in unit area of Shiyang River basin is about 7.30 thousand Yuan · hm -2 · a-l, which is relatively low. Spatially, the service valuation of forest ecosystem in Shiyang River basin has the pattern character of two areas and three centers. The high-value districts are mainly distributed in the Qilian Mountains, which is in the upstream of the Shiyang River basin. The low-value districts are mainly from the piedmont to the north of the desert areas. This distributing pattern of forest ecosystem has vertical zonality, which is akin to the pattern of vegetation landscape. The three high value centers of service valuation are around the upstream valley of Xida River,Xiying River and Jinta River, and they

  8. Low Herbivory among Targeted Reforestation Sites in the Andean Highlands of Southern Ecuador.

    Directory of Open Access Journals (Sweden)

    Marc-Oliver Adams

    Full Text Available Insect herbivory constitutes an important constraint in the viability and management of targeted reforestation sites. Focusing on young experimental stands at about 2000 m elevation in southern Ecuador, we examined foliar damage over one season as a function of tree species and habitat. Native tree species (Successional hardwood: Cedrela montana and Tabebuia chrysantha; fast-growing pioneer: Heliocarpus americanus have been planted among prevailing local landcover types (abandoned pasture, secondary shrub vegetation, and a Pinus patula plantation in 2003/4. Plantation trees were compared to conspecifics in the spontaneous undergrowth of adjacent undisturbed rainforest matched for height and foliar volume. Specifically, we tested the hypotheses that H. americanus as a pioneer species suffers more herbivory compared to the two successional tree species, and that damage is inversely related to habitat complexity. Overall leaf damage caused by folivorous insects (excluding leafcutter ants was low. Average leaf loss was highest among T. chrysantha (7.50% ± 0.19 SE of leaf area, followed by H. americanus (4.67% ± 0.18 SE and C. montana (3.18% ± 0.15 SE. Contrary to expectations, leaf area loss was highest among trees in closed-canopy natural rainforest, followed by pine plantation, pasture, and secondary shrub sites. Harvesting activity of leafcutter ants (Acromyrmex sp. was strongly biased towards T. chrysantha growing in open habitat (mean pasture: 2.5%; shrub: 10.5% where it could result in considerable damage (> 90.0%. Insect folivory is unlikely to pose a barrier for reforestation in the tropical Andean mountain forest zone at present, but leafcutter ants may become problematic if local temperatures increase in the wake of global warming.

  9. High-Up: A Remote Reservoir of Microbial Extremophiles in Central Andean Wetlands

    Science.gov (United States)

    Albarracín, Virginia H.; Kurth, Daniel; Ordoñez, Omar F.; Belfiore, Carolina; Luccini, Eduardo; Salum, Graciela M.; Piacentini, Ruben D.; Farías, María E.

    2015-01-01

    The Central Andes region displays unexplored ecosystems of shallow lakes and salt flats at mean altitudes of 3700 m. Being isolated and hostile, these so-called “High-Altitude Andean Lakes” (HAAL) are pristine and have been exposed to little human influence. HAAL proved to be a rich source of microbes showing interesting adaptations to life in extreme settings (poly-extremophiles) such as alkalinity, high concentrations of arsenic and dissolved salts, intense dryness, large daily ambient thermal amplitude, and extreme solar radiation levels. This work reviews HAAL microbiodiversity, taking into account different microbial niches, such as plankton, benthos, microbial mats and microbialites. The modern stromatolites and other microbialites discovered recently at HAAL are highlighted, as they provide unique modern—though quite imperfect—analogs of environments proxy for an earlier time in Earth's history (volcanic setting and profuse hydrothermal activity, low atmospheric O2 pressure, thin ozone layer and high UV exposure). Likewise, we stress the importance of HAAL microbes as model poly-extremophiles in the study of the molecular mechanisms underlying their resistance ability against UV and toxic or deleterious chemicals using genome mining and functional genomics. In future research directions, it will be necessary to exploit the full potential of HAAL poly-extremophiles in terms of their biotechnological applications. Current projects heading this way have yielded detailed molecular information and functional proof on novel extremoenzymes: i.e., DNA repair enzymes and arsenic efflux pumps for which medical and bioremediation applications, respectively, are envisaged. But still, much effort is required to unravel novel functions for this and other molecules that dwell in a unique biological treasure despite its being hidden high up, in the remote Andes. PMID:26733008

  10. Low Herbivory among Targeted Reforestation Sites in the Andean Highlands of Southern Ecuador

    Science.gov (United States)

    Adams, Marc-Oliver; Fiedler, Konrad

    2016-01-01

    Insect herbivory constitutes an important constraint in the viability and management of targeted reforestation sites. Focusing on young experimental stands at about 2000 m elevation in southern Ecuador, we examined foliar damage over one season as a function of tree species and habitat. Native tree species (Successional hardwood: Cedrela montana and Tabebuia chrysantha; fast-growing pioneer: Heliocarpus americanus) have been planted among prevailing local landcover types (abandoned pasture, secondary shrub vegetation, and a Pinus patula plantation) in 2003/4. Plantation trees were compared to conspecifics in the spontaneous undergrowth of adjacent undisturbed rainforest matched for height and foliar volume. Specifically, we tested the hypotheses that H. americanus as a pioneer species suffers more herbivory compared to the two successional tree species, and that damage is inversely related to habitat complexity. Overall leaf damage caused by folivorous insects (excluding leafcutter ants) was low. Average leaf loss was highest among T. chrysantha (7.50% ± 0.19 SE of leaf area), followed by H. americanus (4.67% ± 0.18 SE) and C. montana (3.18% ± 0.15 SE). Contrary to expectations, leaf area loss was highest among trees in closed-canopy natural rainforest, followed by pine plantation, pasture, and secondary shrub sites. Harvesting activity of leafcutter ants (Acromyrmex sp.) was strongly biased towards T. chrysantha growing in open habitat (mean pasture: 2.5%; shrub: 10.5%) where it could result in considerable damage (> 90.0%). Insect folivory is unlikely to pose a barrier for reforestation in the tropical Andean mountain forest zone at present, but leafcutter ants may become problematic if local temperatures increase in the wake of global warming. PMID:26963395

  11. Taxonomic and functional assignment of cloned sequences from high Andean forest soil metagenome.

    Science.gov (United States)

    Montaña, José Salvador; Jiménez, Diego Javier; Hernández, Mónica; Angel, Tatiana; Baena, Sandra

    2012-02-01

    Total metagenomic DNA was isolated from high Andean forest soil and subjected to taxonomical and functional composition analyses by means of clone library generation and sequencing. The obtained yield of 1.7 μg of DNA/g of soil was used to construct a metagenomic library of approximately 20,000 clones (in the plasmid p-Bluescript II SK+) with an average insert size of 4 Kb, covering 80 Mb of the total metagenomic DNA. Metagenomic sequences near the plasmid cloning site were sequenced and them trimmed and assembled, obtaining 299 reads and 31 contigs (0.3 Mb). Taxonomic assignment of total sequences was performed by BLASTX, resulting in 68.8, 44.8 and 24.5% classification into taxonomic groups using the metagenomic RAST server v2.0, WebCARMA v1.0 online system and MetaGenome Analyzer v3.8 software, respectively. Most clone sequences were classified as Bacteria belonging to phlya Actinobacteria, Proteobacteria and Acidobacteria. Among the most represented orders were Actinomycetales (34% average), Rhizobiales, Burkholderiales and Myxococcales and with a greater number of sequences in the genus Mycobacterium (7% average), Frankia, Streptomyces and Bradyrhizobium. The vast majority of sequences were associated with the metabolism of carbohydrates, proteins, lipids and catalytic functions, such as phosphatases, glycosyltransferases, dehydrogenases, methyltransferases, dehydratases and epoxide hydrolases. In this study we compared different methods of taxonomic and functional assignment of metagenomic clone sequences to evaluate microbial diversity in an unexplored soil ecosystem, searching for putative enzymes of biotechnological interest and generating important information for further functional screening of clone libraries. PMID:21792685

  12. A novel cold active esterase derived from Colombian high Andean forest soil metagenome.

    Science.gov (United States)

    Jiménez, Diego Javier; Montaña, José Salvador; Alvarez, Diana; Baena, Sandra

    2012-01-01

    In order to search new lipolytic enzymes and conduct bioprospecting of microbial communities from high Andean forest soil, a metagenomic library of approximately 20,000 clones was constructed in Escherichia coli using plasmid p-Bluescript II SK+. The library covered 80 Mb of the metagenomic DNA mainly from Proteobacteria, Actinobacteria and Acidobacteria. Two clones with lipolytic activity in tributyrin as a substrate were recovered. Clone BAA3G2 (pSK-estGX1) was selected and the entire 4.6 Kb insert sequence was determined. The sequence had a GC content of 70.6% and could be derived from an undescribed Actinobacteria genome. One open reading frame encoded a polypeptide of 210 amino acids (gene estGX1) with a molecular mass of 22.4 kDa that contained the pentapeptide G-P-S-G-G near the N-terminus essential for lipase activity and the putative catalytic triad was identified, also a putative ribosomal binding site located 18 bp upstream the estGX1 ATG start codon was identified. The phylogenetic analysis suggested that the protein belonged to a new lipase family. The secreted enzyme showed a preference for short length fatty acids, with specific activity against p-nitrophenyl-butyrate (0.142 U/mg of total protein), it was cold active with relative activity of 30% at 10°C and moderately thermo active with relative activity of 80% at 50°C and had a pH optimum of 8.0 at 40°C. PMID:22806812

  13. Impact of solar radiation on bacterioplankton in Laguna Vilama, a hypersaline Andean lake (4650 m)

    Science.gov (United States)

    FaríAs, MaríA. Eugenia; FernáNdez-Zenoff, Verónica; Flores, Regina; OrdóñEz, Omar; EstéVez, Cristina

    2009-06-01

    Laguna Vilama is a hypersaline Lake located at 4660 m altitude in the northwest of Argentina high up in the Andean Puna. The impact of ultraviolet (UV) radiation on bacterioplankton was studied by collecting samples at different times of the day. Molecular analysis (DGGE) showed that the bacterioplankton community is characterized by Gamma-proteobacteria (Halomonas sp., Marinobacter sp.), Alpha-proteobacteria (Roseobacter sp.), HGC (Agrococcus jenensis and an uncultured bacterium), and CFB (uncultured Bacteroidetes). During the day, minor modifications in bacterial diversity such as intensification of Bacteroidetes' signal and an emergence of Gamma-proteobacteria (Marinobacter flavimaris) were observed after solar exposure. DNA damage, measured as an accumulation of Cyclobutane Pyrimidine Dimers (CPDs), in bacterioplankton and naked DNA increased from 100 CPDs MB-1 at 1200 local time (LT) to 300 CPDs MB-1 at 1600 LT, and from 80 CPDs MB-1 at 1200 LT to 640 CPDs MB-1 at 1600 LT, respectively. In addition, pure cultures of Pseudomonas sp. V1 and Brachybacterium sp. V5, two bacteria previously isolated from this environment, were exposed simultaneously with the community, and viability of both strains diminished after solar exposure. No CPD accumulation was observed in either of the exposed cultures, but an increase in mutagenesis was detected in V5. Of both strains only Brachybacterium sp. V5 showed CPD accumulation in naked DNA. These results suggest that the bacterioplankton community is well adapted to this highly solar irradiated environment showing little accumulation of CPDs and few changes in the community composition. They also demonstrate that these microorganisms contain efficient mechanisms against UV damage.

  14. Bioactive maca (Lepidium meyenii) alkamides are a result of traditional Andean postharvest drying practices.

    Science.gov (United States)

    Esparza, Eliana; Hadzich, Antonella; Kofer, Waltraud; Mithöfer, Axel; Cosio, Eric G

    2015-08-01

    Maca, Lepidium meyenii Walpers (Brassicaceae), is an annual herbaceous plant native to the high plateaus of the Peruvian central Andes. Its underground storage hypocotyls have been a traditional medicinal agent and dietary staple since pre-Columbian times. Reported properties include energizing and fertility-enhancing effects. Published reports have focused on the benzylalkamides (macamides) present in dry hypocotyls as one of the main bioactive components. Macamides are secondary amides formed by benzylamine and a fatty acid moiety, with varying hydrocarbon chain lengths and degree of unsaturation. Although it has been assumed that they are usually present in fresh undamaged tissues, analyses show them to be essentially absent from them. However, hypocotyls dried by traditional Andean postharvest practices or industrial oven drying contain up to 800μgg(-1) dry wt (2.3μmolg(-1) dry wt) of macamides. In this study, the generation of macamides and their putative precursors were studied during nine-week traditional drying trials at 4200m altitude and in ovens under laboratory conditions. Freeze-thaw cycles in the open field during drying result in tissue maceration and release of free fatty acids from storage and membrane lipids up to levels of 1200μgg(-1) dry wt (4.3μmolg(-1) dry wt). Endogenous metabolism of the isothiocyanates generated from glucosinolate hydrolysis during drying results in maximal benzylamine values of 4300μgg(-1) dry wt (40.2μmolg(-1) dry wt). Pearson correlation coefficients of the accumulation profiles of benzylamine and free fatty acid to that of macamides showed good values of 0.898 and 0.934, respectively, suggesting that both provide sufficient substrate for amide synthesis during the drying process. PMID:25817836

  15. Imaging the Seismic Cycle in the Central Andean Subduction Zone from Geodetic Observations

    Science.gov (United States)

    Ortega-Culaciati, F.; Becerra-Carreño, V. C.; Socquet, A.; Jara, J.; Carrizo, D.; Norabuena, E. O.; Simons, M.; Vigny, C.; Bataille, K. D.; Moreno, M.; Baez, J. C.; Comte, D.; Contreras-Reyes, E.; Delorme, A.; Genrich, J. F.; Klein, E.; Ortega, I.; Valderas, M. C.

    2015-12-01

    We aim to quantify spatial and temporal evolution of fault slip behavior during all stages of the seismic cycle in subduction megathrusts, with the eventual goal of improving our understanding of the mechanical behavior of the subduction system and its implications for earthquake and tsunami hazards. In this work, we analyze the portion of the Nazca-SouthAmerican plates subduction zone affected by the 1868 southern Peru and 1877 northern Chile mega-earthquakes. The 1868 and 1878 events defined a seismic gap that did not experience a large earthquake for over 124 years. Only recently, the 1995 Mw 8.1 Antofagasta, 2001 Mw 8.4 Arequipa, 2007 Mw 7.7 Tocopilla, and 2014 Mw 8.2 Pisagua earthquakes released only a small fraction of the potential slip budget, thereby raising concerns about continued seismic and tsunami hazard. We use over a decade of observations from continuous and campaign GPS networks to analyze inter-seismic strain accumulation, as well as co-seimic deformation associated to the more recent earthquakes in the in the Central Andean region. We obtain inferences of slip (and back-slip) behavior using a consistent and robust inversion framework that accounts for the spatial variability of the constraint provided by the observations on slip across the subduction megathrust. We present an updated inter-seismic coupling model and estimates of pre-, co- and post- seismic slip behavior associated with the most recent 2014 Mw 8.2 Pisagua earthquake. We analyze our results, along with published information on the recent and historical large earthquakes, to characterize the regions of the megathrust that tend to behave aseismically, and those that are capable to accumulate a slip budget (ultimately leading to the generation of large earthquakes), to what extent such regions may overlap, and discuss the potential for large earthquakes in the region.

  16. Monitoring the Diversity of Hunting Ants (Hymenoptera: Formicidae) on a Fragmented and Restored Andean Landscape.

    Science.gov (United States)

    Herrera-Rangel, J; Jiménez-Carmona, E; Armbrecht, I

    2015-10-01

    Hunting ants are predators of organisms belonging to different trophic levels. Their presence, abundance, and diversity may reflect the diversity of other ants and contribute to evaluate habitat conditions. Between 2003 and 2005 the restoration of seven corridors in an Andean rural landscape of Colombia was performed. The restoration took place in lands that were formerly either forestry plantations or pasturelands. To evaluate restoration progress, hunting ants were intensely sampled for 7 yr, using sifted leaf litter and mini-Winkler, and pitfall traps in 21 plots classified into five vegetation types: forests, riparian forests, two types of restored corridors, and pasturelands. The ant communities were faithful to their habitat over time, and the main differences in ant composition, abundance, and richness were due to differences among land use types. The forests and riparian forests support 45% of the species in the landscape while the restored corridors contain between 8.3-25%. The change from forest to pasturelands represents a loss of 80% of the species. Ant composition in restored corridors was significantly different than in forests but restored corridors of soil of forestry plantations retained 16.7% more species than restored corridors from pasturelands. Ubiquitous hunting ants, Hypoponera opacior (Forel) and Gnamptogenys ca andina were usually associated with pastures and dominate restored corridors. Other cryptic, small, and specialized hunting ants are not present in the restored corridors. Results suggest that the history of land use is important for the biodiversity of hunting ants but also that corridors have not yet effectively contributed toward conservation goals. PMID:26314006

  17. Low Herbivory among Targeted Reforestation Sites in the Andean Highlands of Southern Ecuador.

    Science.gov (United States)

    Adams, Marc-Oliver; Fiedler, Konrad

    2016-01-01

    Insect herbivory constitutes an important constraint in the viability and management of targeted reforestation sites. Focusing on young experimental stands at about 2000 m elevation in southern Ecuador, we examined foliar damage over one season as a function of tree species and habitat. Native tree species (Successional hardwood: Cedrela montana and Tabebuia chrysantha; fast-growing pioneer: Heliocarpus americanus) have been planted among prevailing local landcover types (abandoned pasture, secondary shrub vegetation, and a Pinus patula plantation) in 2003/4. Plantation trees were compared to conspecifics in the spontaneous undergrowth of adjacent undisturbed rainforest matched for height and foliar volume. Specifically, we tested the hypotheses that H. americanus as a pioneer species suffers more herbivory compared to the two successional tree species, and that damage is inversely related to habitat complexity. Overall leaf damage caused by folivorous insects (excluding leafcutter ants) was low. Average leaf loss was highest among T. chrysantha (7.50% ± 0.19 SE of leaf area), followed by H. americanus (4.67% ± 0.18 SE) and C. montana (3.18% ± 0.15 SE). Contrary to expectations, leaf area loss was highest among trees in closed-canopy natural rainforest, followed by pine plantation, pasture, and secondary shrub sites. Harvesting activity of leafcutter ants (Acromyrmex sp.) was strongly biased towards T. chrysantha growing in open habitat (mean pasture: 2.5%; shrub: 10.5%) where it could result in considerable damage (> 90.0%). Insect folivory is unlikely to pose a barrier for reforestation in the tropical Andean mountain forest zone at present, but leafcutter ants may become problematic if local temperatures increase in the wake of global warming. PMID:26963395

  18. High-up: a remote reservoir of microbial extremophiles at Central Andean Wetlands

    Directory of Open Access Journals (Sweden)

    Virginia Helena Albarracín

    2015-12-01

    Full Text Available The Central Andes region displays unexplored ecosystems of shallow lakes and salt flats at mean altitudes of 3,700 m. Being isolated and hostile, these so-called High-Altitude Andean Lakes (HAAL are pristine and have been exposed to little human influence. HAAL proved to be a rich source of microbes showing interesting adaptations to life in extreme settings (poly-extremophiles such as alkalinity, high concentrations of arsenic and dissolved salts, intense dryness, large daily ambient thermal amplitude, and extreme solar radiation levels. This work reviews HAAL microbiodiversity, taking into account different microbial niches, such as plankton, benthos, microbial mats and microbialites. The modern stromatolites and other microbialites discovered recently at HAAL are highlighted, as they provide unique modern -though quite imperfect- analogues of environments proxy for an earlier time in Earth’s history (volcanic setting and profuse hydrothermal activity, low atmospheric O2 pressure, thin ozone layer and high UV exposure. Likewise, we stress the importance of HAAL microbes as model poly-extremophiles in the study of the molecular mechanisms underlying their resistance ability against UV and toxic or deleterious chemicals using genome mining and functional genomics. In future research directions, it will be necessary to exploit the full potential of HAAL poly-extremophiles in terms of their biotechnological applications. Current projects heading this way have yielded detailed molecular information and functional proof on novel extremoenzymes: i.e. DNA repair enzymes and arsenic efflux pumps for which medical and bioremediation applications, respectively, are envisaged. But still, much effort is required to unravel novel functions for this and other molecules that dwell in a unique biological treasure despite its being hidden high up, in the remote Andes.

  19. Analysis of the rainfall runoff processes of Andean ecosystems in Southern Ecuador : using hydrometric, tracers and modeling approaches

    OpenAIRE

    Crespo Sanchez, Patricio Javier

    2012-01-01

    The tropical Andes is one of the world’s 25 most species rich and exceptional areas, and the montane forest ecosystems in particular are considered as biodiversity hotspots. Also the high altitude páramo region, between 3500 and 5000 m a.s.l., is another important Andean ecosystem. The low temperatures, high intra-day temperature variability and the tendency to be consistently humid throughout the year creates an environment ideal for wet páramo flora primarily consisting of tussock-grasses o...

  20. Rodent consumption by Philodryas psammophidea (Serpentes: Colubridae), from the inter-andean dry valleys of central Bolivia

    OpenAIRE

    Quinteros-Muñoz, Oliver; Peñaranda, Diego A.; Navarro, Freddy

    2010-01-01

    In May 18, 2009 we found an adult female of Philodryas psammophidea (930 mm SVL), at a side of a crop field in the Tabacal valley (18º23'7.42" S – 64º38'7.88" W, 2015 m), Narciso Campero province southern Cochabamba, Bolivia. Ecologically, this valley belongs to the Inter-Andean Dry Forests of Bolivia. In the stomach of the snake probably killed by a settler, there was an adult female of Graomys domorum (Phyllotini; Sigmodontidae), a native rodent species widely distributed in the r...

  1. Rodent consumption by Philodryas psammophidea (Serpentes: Colubridae, from the inter-andean dry valleys of central Bolivia

    Directory of Open Access Journals (Sweden)

    Quinteros-Muñoz, Oliver

    2010-12-01

    Full Text Available In May 18, 2009 we found an adult female of Philodryas psammophidea (930 mm SVL, at a side of a crop field in the Tabacal valley (18º23'7.42" S – 64º38'7.88" W, 2015 m, Narciso Campero province southern Cochabamba, Bolivia. Ecologically, this valley belongs to the Inter-Andean Dry Forests of Bolivia. In the stomach of the snake probably killed by a settler, there was an adult female of Graomys domorum (Phyllotini; Sigmodontidae, a native rodent species widely distributed in the region.

  2. Carbon isotopic evidence from paleosols for mixed C 3/C 4 vegetation in the Bogota Basin, Colombia

    Science.gov (United States)

    Mora, Germán; Pratt, Lisa M.

    2002-04-01

    Pollen reconstructions in the Bogota basin (Colombia) indicate the expansion of tropical high-altitude grassland (paramo) at the expense of Andean forests during glacial intervals. The carbon isotopic composition (δ 13C) of soil organic matter (SOM) can be a useful indicator of changes in vegetation affecting grasslands because it distinguishes between two groups of grasses (C 3 and C 4) adapted to different ecological environments. Values of SOM δ 13C were determined in four weathering profiles containing both modern (Holocene) soils and paleosols formed during the Last Glacial Stage. These profiles are located along an altitudinal transect in the Bogota basin, extending from 2550 to 3100 m. Values of SOM δ 13C in the topsoil horizons reflect those of the native C 3 vegetation that currently dominates the ecosystems in the Colombian Andes. Although C 4 grasses are currently negligible in the basin, elevated SOM δ 13C values indicative of C 4 plants were found in two Holocene soils. Environmental changes or ancient agricultural activities could explain the increased abundance of these plants in the basin during the late Holocene. Isotopic values in the studied paleosols revealed the presence of a mixed C 3/C 4 vegetation in the basin during the Last Glacial Stage, thus indicating the expansion of C 4 grasses. We hypothesized that lowered pCO 2 and possibly reduced rainfall resulted in the colonization of the tropical Andes by lowland C 4 grasses despite of prevailing cooler temperatures.

  3. Floristic diversity of the upper river basin Tambo-Ichuña (Moquegua, Peru

    Directory of Open Access Journals (Sweden)

    Daniel B. Montesinos-Tubée

    2011-06-01

    Full Text Available A study of the floristic diversity of vascular plants is presented from the basin of the Tambo-Ichuña River, the high Andean Puna plateau and wetlands of Ichuña, Ubinas and Yunga Districts (3400 - 4700 m altitude, General Sanchez Cerro Province, Department of Moquegua, Peru. Vascular flora is composed of 70 families, 238 genera and 404 species. The Magnoliopsida represent 78% of the species, Liliopsida 16%, Gymnosperms 0.5% and Pteridophytes 6%. Among lifeforms, the Hemicryptophytes are the most numerous. Three vegetation formations have been identified, the humid scrubland being the most diverse in species richness. Between endemic species, 42 taxa are exclusive to Peru. A total number of 272 new additions of vascular species to the flora of the department of Moquegua are presented.

  4. Tectonic Evolution and Petroleum Systems in the Junggar Basin

    Institute of Scientific and Technical Information of China (English)

    WANG Weifeng; CHEN Yequan

    2004-01-01

    The Junggar basin is located in the northern part of Xinjiang of China. It is part of the Kazakstan plate,surrounded by the Paleozoic folded mountains: the Halaart, Zayier and Chepaizi Mountains in the northwest, the Qingelidi and Karamaili Mountains in the northeast, and the Tianshan Mountains in the south. In different evolution stages, the basin's types are different, and the stratigraphy and deposition are also different. From the Carboniferous to Tertiary the basin has in turn gone through rift basin, collision foreland basin, intraplate depression basin and regenerated foreland basin. Based on an analysis of thermal evolution history and buried history of the source rocks, three major periods of oil generation are found in the basin. According to the characteristics of source rock distribution, evolution, oil-source correlation, structure and multi-phase and mixed pools, the Junggar basin could be divided into 4 composite petroleum systems. Due to the variation in sedimentary facies, difference in structural patterns and development histories, the petroleum pool-forming conditions in different areas and horizons are greatly different, so are the petroleum pool types,the accumulation mechanisms in different areas and horizons.

  5. Paleogeographic and tectonic controls on the evolution of Cenozoic basins in the Altiplano and Western Cordillera of southern Peru

    Science.gov (United States)

    Carlotto, Víctor

    2013-03-01

    Integrated studies of stratigraphy, sedimentology, paleogeography and tectonic controls on Cenozoic basins provide the basis for a series of time-slice reconstructions of basin evolution in the Andes of southern Peru. The Altiplano and adjacent margin of the Western Cordillera are characterized by several Paleocene-Miocene synorogenic continental basins with thicknesses locally exceeding 10 km. The evolution of these basins has been controlled by NW-trending tectonic features that mark the Altiplano-Western Cordillera and Altiplano-Eastern Cordillera boundaries and the Condoroma structural high. Sedimentary deposits of Paleocene age preserved in the Altiplano are the result of nonmarine sedimentation in a distal foreland basin. During the early Eocene, predominantly dextral strike-slip movements in the Altiplano between the Cusco-Lagunillas and Urcos-Ayaviri fault systems created the transpressional Kayra basin. The Soncco and Anta basins (middle Eocene-early Oligocene) are related to NE shortening (43-30 Ma) and represent proximal, wedge-top and foredeep basin environments preserved on the Altiplano. At ~ 29-28 Ma, a change to predominantly E-W shortening produced sinistral strike-slip motion along NW-striking faults, resulting in intermontane, transpressional basins. In the Altiplano, the Tinajani and Punacancha (29-5 Ma), and Paruro (12-6 Ma) basins were controlled by the Cusco-Lagunillas and the Urcos-Ayaviri fault systems. The Maure, Tincopalca-Huacochullo and Condoroma basins (22-5 Ma) of the Western Cordillera developed between the Condoroma high and the Cusco-Lagunillas fault system. Oligocene-Miocene sedimentation commonly evolved from proximal (alluvial) facies along the borders to distal (lacustrine) facies. These basins were linked to sinistral strike-slip faults that evolved into reve