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Sample records for western amazon basin

  1. Evolution of wet-day and dry-day frequency in the western Amazon basin: Relationship with atmospheric circulation and impacts on vegetation

    Science.gov (United States)

    Espinoza, Jhan Carlo; Segura, Hans; Ronchail, Josyane; Drapeau, Guillaume; Gutierrez-Cori, Omar

    2016-11-01

    This paper documents the spatiotemporal evolution of wet-day and dry-day frequency (WDF and DDF) in the western Amazon, its relationships with oceanic and atmospheric variability and possible impact on vegetation. WDF and DDF changed significantly during the 1980-2009 period (p DDF increased significantly over the central and southern part of this region (Ucayali basin) after 1986. Average annual DDF was 16.2 days before 1986 and 23.8 days afterward (+47% after 1986). Interannual variability in WDF appears to be modulated by changes in Pacific SST and the Walker cell during the November-March season. This mechanism enhances convective activity over the northern part of the western Amazon. The increase in DDF is related to warming of the North Tropical Atlantic SST, which produces changes in the Hadley cell and subsidence over the central and the southern western Amazon. More intense seasonal hydrological extremes in the western Amazon therefore appear to be related to changes in WDF and DDF that occurred in 1995 and 1986, respectively. During the 2001-2009 period, an index of vegetation condition (NDVI) appears negatively correlated with DDF (r = -0.95; p < 0.0001). This suggests that vegetation in the western Amazon is mainly water limited, rather than light limited and indicates that the vegetation is highly sensitive to concentration of rainfall.

  2. Seasonal variability in methane and nitrous oxide fluxes from tropical peatlands in the western Amazon basin

    Directory of Open Access Journals (Sweden)

    Y. A. Teh

    2017-08-01

    Full Text Available The Amazon plays a critical role in global atmospheric budgets of methane (CH4 and nitrous oxide (N2O. However, while we have a relatively good understanding of the continental-scale flux of these greenhouse gases (GHGs, one of the key gaps in knowledge is the specific contribution of peatland ecosystems to the regional budgets of these GHGs. Here we report CH4 and N2O fluxes from lowland tropical peatlands in the Pastaza–Marañón foreland basin (PMFB in Peru, one of the largest peatland complexes in the Amazon basin. The goal of this research was to quantify the range and magnitude of CH4 and N2O fluxes from this region, assess seasonal trends in trace gas exchange, and determine the role of different environmental variables in driving GHG flux. Trace gas fluxes were determined from the most numerically dominant peatland vegetation types in the region: forested vegetation, forested (short pole vegetation, Mauritia flexuosa-dominated palm swamp, and mixed palm swamp. Data were collected in both wet and dry seasons over the course of four field campaigns from 2012 to 2014. Diffusive CH4 emissions averaged 36.05 ± 3.09 mg CH4–C m−2 day−1 across the entire dataset, with diffusive CH4 flux varying significantly among vegetation types and between seasons. Net ebullition of CH4 averaged 973.3 ± 161.4 mg CH4–C m−2 day−1 and did not vary significantly among vegetation types or between seasons. Diffusive CH4 flux was greatest for mixed palm swamp (52.0 ± 16.0 mg CH4–C m−2 day−1, followed by M. flexuosa palm swamp (36.7 ± 3.9 mg CH4–C m−2 day−1, forested (short pole vegetation (31.6 ± 6.6 mg CH4–C m−2 day−1, and forested vegetation (29.8 ± 10.0 mg CH4–C m−2 day−1. Diffusive CH4 flux also showed marked seasonality, with divergent seasonal patterns among ecosystems. Forested vegetation and mixed palm swamp showed significantly higher

  3. Seasonal variability in methane and nitrous oxide fluxes from tropical peatlands in the western Amazon basin

    Science.gov (United States)

    Arn Teh, Yit; Murphy, Wayne A.; Berrio, Juan-Carlos; Boom, Arnoud; Page, Susan E.

    2017-08-01

    The Amazon plays a critical role in global atmospheric budgets of methane (CH4) and nitrous oxide (N2O). However, while we have a relatively good understanding of the continental-scale flux of these greenhouse gases (GHGs), one of the key gaps in knowledge is the specific contribution of peatland ecosystems to the regional budgets of these GHGs. Here we report CH4 and N2O fluxes from lowland tropical peatlands in the Pastaza-Marañón foreland basin (PMFB) in Peru, one of the largest peatland complexes in the Amazon basin. The goal of this research was to quantify the range and magnitude of CH4 and N2O fluxes from this region, assess seasonal trends in trace gas exchange, and determine the role of different environmental variables in driving GHG flux. Trace gas fluxes were determined from the most numerically dominant peatland vegetation types in the region: forested vegetation, forested (short pole) vegetation, Mauritia flexuosa-dominated palm swamp, and mixed palm swamp. Data were collected in both wet and dry seasons over the course of four field campaigns from 2012 to 2014. Diffusive CH4 emissions averaged 36.05 ± 3.09 mg CH4-C m-2 day-1 across the entire dataset, with diffusive CH4 flux varying significantly among vegetation types and between seasons. Net ebullition of CH4 averaged 973.3 ± 161.4 mg CH4-C m-2 day-1 and did not vary significantly among vegetation types or between seasons. Diffusive CH4 flux was greatest for mixed palm swamp (52.0 ± 16.0 mg CH4-C m-2 day-1), followed by M. flexuosa palm swamp (36.7 ± 3.9 mg CH4-C m-2 day-1), forested (short pole) vegetation (31.6 ± 6.6 mg CH4-C m-2 day-1), and forested vegetation (29.8 ± 10.0 mg CH4-C m-2 day-1). Diffusive CH4 flux also showed marked seasonality, with divergent seasonal patterns among ecosystems. Forested vegetation and mixed palm swamp showed significantly higher dry season (47.2 ± 5.4 mg CH4-C m-2 day-1 and 85.5 ± 26.4 mg CH4-C m-2 day-1, respectively) compared to wet season emissions

  4. Oil and gas projects in the Western Amazon: threats to wilderness, biodiversity, and indigenous peoples

    National Research Council Canada - National Science Library

    Finer, Matt; Jenkins, Clinton N; Pimm, Stuart L; Keane, Brian; Ross, Carl

    2008-01-01

    The western Amazon is the most biologically rich part of the Amazon basin and is home to a great diversity of indigenous ethnic groups, including some of the world's last uncontacted peoples living...

  5. The Amazon Basin in transition

    Science.gov (United States)

    Eric A. Davidson; Alessandro C. de Araujo; Paulo Artaxo; Jennifer K. Balch; I. Foster Brown; Mercedes M.C. Bustamente; Michael T. Coe; Ruth S. DeFriess; Michael Keller; Marcos Longo; J. William Munger; Wilfrid Schroeder; Britaldo Soares-Filho; Carlos M. Souza, Jr.; Steven C. Wofsy

    2012-01-01

    Agricultural expansion and climate variability have become important agents of disturbance in the Amazon basin. Recent studies have demonstrated considerable resilience of Amazonian forests to moderate annual drought, but they also show that interactions between deforestation, fire and drought potentially lead to losses of carbon storage and changes in regional...

  6. Amazon basin: a system in equilibrium.

    Science.gov (United States)

    Salati, E; Vose, P B

    1984-07-13

    Despite the very active deforestation of the last decade, the Amazon Basin is still primarily covered with trees and is a system in equilibrium. The Andes form a barrier at the western end of the basin and, coupled with the prevailing easterly winds, ensure an almost unique precipitation and water-recycling regime. On average 50 percent of the precipitation is recycled, and in some areas even more. The soils are poor. Most of the nitrogen and phosphorus is found in the soil, and the remaining nutrient elements are found in the standing biomass. There is some nutrient recycling and little loss from the intact ecosystem, and the small input of nutrients from precipitation maintains a small positive nutrient balance. Continued large-scale deforestation is likely to lead to increased erosion and water runoff with initial flooding in the lower Amazon, together with reduced evapotranspiration and ultimately reduced precipitation. Reduced precipitation in the Amazon could increase the tendency toward continentality and adversely affect climate and the present agriculture in south-central Brazil.

  7. Diversity of palm uses in the western Amazon

    DEFF Research Database (Denmark)

    Paniagua Zambrana, N.Y.; Byg, A.; Svenning, J.-C.

    2007-01-01

    Abstract  We used palm knowledge to understand the interaction between people and the rainforests and the factors that influence this dynamic process. We interviewed 278 informants in 12 villages in the Pastaza and Madidi areas of the western Amazon basin. Together they used 38 different palm spe...

  8. Damming the rivers of the Amazon basin

    Science.gov (United States)

    Latrubesse, Edgardo M.; Arima, Eugenio Y.; Dunne, Thomas; Park, Edward; Baker, Victor R.; D'Horta, Fernando M.; Wight, Charles; Wittmann, Florian; Zuanon, Jansen; Baker, Paul A.; Ribas, Camila C.; Norgaard, Richard B.; Filizola, Naziano; Ansar, Atif; Flyvbjerg, Bent; Stevaux, Jose C.

    2017-06-01

    More than a hundred hydropower dams have already been built in the Amazon basin and numerous proposals for further dam constructions are under consideration. The accumulated negative environmental effects of existing dams and proposed dams, if constructed, will trigger massive hydrophysical and biotic disturbances that will affect the Amazon basin’s floodplains, estuary and sediment plume. We introduce a Dam Environmental Vulnerability Index to quantify the current and potential impacts of dams in the basin. The scale of foreseeable environmental degradation indicates the need for collective action among nations and states to avoid cumulative, far-reaching impacts. We suggest institutional innovations to assess and avoid the likely impoverishment of Amazon rivers.

  9. Reexamining the late Cenozoic geologic evolution of the Amazon basin

    Science.gov (United States)

    Rigsby, C. A.; Latrubesse, E. M.; Baker, P. A.; Silva, C. G.

    2010-12-01

    The recent geologic evolution of the Amazon basin has been the focus of many recent studies. Our own research and our review of the literature suggest a need for reevaluation of many aspects of this history including several key questions: What was the timing of Andean uplift (especially, the Western Cordillera)? What is the relationship between the northernmost Solimões Formation and northern Andean tectonic activity? What is the precise age of the lowermost levels of the Solimões Formation? Were there marine incursions? Are tidal deposits recorded in Amazonia? Was there a very large, long-lived, Miocene "Pebas" megalake in the western Amazon? When did the trans-continental, eastern outlet, Amazon drainage become established? What is the antiquity of the Amazon fan? Correct answers to these questions are essential in order to gain a better understanding of the climatic and biogeographic history of the Amazon basin. Although several authors have suggested the existence of late Miocene tidal sediments deposited during a sea-level high stand and marine transgressions into the Amazon basin from the north (Caribbean Sea) or from the south (Paranáense Sea), both the existence of a late Miocene seaway through western Amazonia and the existence of thousands of square kilometers affected by tides are difficult to support. The faunal composition and pollen content of the upper Miocene Solimões Formation are inconsistent with tidal/marine environments. And, as we have demonstrated, deposits in Peruvian Amazonia that have been attributed to Miocene tidal environments are actually fluvial sediments that have been environmentally and chronologically misinterpreted. Further, the existence of a giant paleolake in western Amazonia during the middle to late Miocene is inconsistent with our paleoenvironmental reconstructions of shifting rivers in aggradational conditions - reconstructions that are consistent with the interpretations of the Solimões Formation in other parts of

  10. Evapotranspiration seasonality across the Amazon Basin

    Science.gov (United States)

    Eiji Maeda, Eduardo; Ma, Xuanlong; Wagner, Fabien Hubert; Kim, Hyungjun; Oki, Taikan; Eamus, Derek; Huete, Alfredo

    2017-06-01

    Evapotranspiration (ET) of Amazon forests is a main driver of regional climate patterns and an important indicator of ecosystem functioning. Despite its importance, the seasonal variability of ET over Amazon forests, and its relationship with environmental drivers, is still poorly understood. In this study, we carry out a water balance approach to analyse seasonal patterns in ET and their relationships with water and energy drivers over five sub-basins across the Amazon Basin. We used in situ measurements of river discharge, and remotely sensed estimates of terrestrial water storage, rainfall, and solar radiation. We show that the characteristics of ET seasonality in all sub-basins differ in timing and magnitude. The highest mean annual ET was found in the northern Rio Negro basin (˜ 1497 mm year-1) and the lowest values in the Solimões River basin (˜ 986 mm year-1). For the first time in a basin-scale study, using observational data, we show that factors limiting ET vary across climatic gradients in the Amazon, confirming local-scale eddy covariance studies. Both annual mean and seasonality in ET are driven by a combination of energy and water availability, as neither rainfall nor radiation alone could explain patterns in ET. In southern basins, despite seasonal rainfall deficits, deep root water uptake allows increasing rates of ET during the dry season, when radiation is usually higher than in the wet season. We demonstrate contrasting ET seasonality with satellite greenness across Amazon forests, with strong asynchronous relationships in ever-wet watersheds, and positive correlations observed in seasonally dry watersheds. Finally, we compared our results with estimates obtained by two ET models, and we conclude that neither of the two tested models could provide a consistent representation of ET seasonal patterns across the Amazon.

  11. Oil and Gas Projects in the Western Amazon: Threats to Wilderness, Biodiversity, and Indigenous Peoples

    OpenAIRE

    Matt Finer; Clinton N Jenkins; Stuart L. Pimm; Brian Keane; Carl Ross

    2008-01-01

    BACKGROUND: The western Amazon is the most biologically rich part of the Amazon basin and is home to a great diversity of indigenous ethnic groups, including some of the world's last uncontacted peoples living in voluntary isolation. Unlike the eastern Brazilian Amazon, it is still a largely intact ecosystem. Underlying this landscape are large reserves of oil and gas, many yet untapped. The growing global demand is leading to unprecedented exploration and development in the region. METHODOLO...

  12. Geological development of amazon and orinoco basins

    NARCIS (Netherlands)

    Wesselingh, F.P.; Hoorn, C.; Albert, J.S.; Reis, R.E.

    2011-01-01

    This chapter examines the geological development of the Orinoco and Amazon River basins. It analyzes the evolution of aquatic Amazonian ecosystems from the Late Cretaceous to the Quaternary period and provides and considers the potential impacts on the development of modern Amazonian fish faunas. It

  13. Analysis of tectonic-controlled fluvial morphology and sedimentary processes of the western Amazon Basin: an approach using satellite images and digital elevation model

    Directory of Open Access Journals (Sweden)

    Clauzionor L. Silva

    2007-12-01

    Full Text Available An investigation of the tectonic controls of the fluvial morphology and sedimentary processes of an area located southwest of Manaus in the Amazon Basin was conducted using orbital remote sensing data. In this region, low topographic gradients represent a major obstacle for morphotectonic analysis using conventional methods. The use of remote sensing data can contribute significantly to overcome this limitation. In this instance, remote sensing data comprised digital elevation model (DEM acquired by the Shuttle Radar Topographic Mission (SRTM and Landsat Thematic Mapper images. Advanced image processing techniques were employed for enhancing the topographic textures and providing a three-dimensional visualization, hence allowing interpretation of the morphotectonic elements. This led to the recognition of main tectonic compartments and several morphostructural features and landforms related to the neotectonic evolution of this portion of the Amazon Basin. Features such as fault scarps, anomalous drainage patterns, aligned ridges, spurs and valleys, are expressed in the enhanced images as conspicuous lineaments along NE-SW, NW-SE, E-W and N-S directions. These features are associated to the geometry of alternated horst and graben structures, the latter filled by recent sedimentary units. Morphotectonic interpretation using this approach has proven to be efficient and permitted to recognize new tectonic features that were named Asymmetric Ariaú Graben, Rombohedral Manacapuru Basin and Castanho-Mamori Graben.Uma investigação do controle tectônico da morfologia fluvial e dos processos sedimentares de uma área localizada a sudoeste da cidade de Manaus, na Bacia do Amazonas, foi conduzida a partir do uso de dados de sensores remotos orbitais. Nessa região, o baixo gradiente topográfico representa o principal obstáculo para a análise morfotectônica usando métodos convencionais. O uso de dados de sensores remotos pode contribuir

  14. Possible Antarctic Forcing Over Amazon Basin Climate During The LGIT

    Science.gov (United States)

    Ettwein, V. J.; Maslin, M. A.; Burns, S. J.; Leng, M. J.; Weyhenmeyer, C. E.

    2005-12-01

    The Amazon Basin is the Earth's largest and most intense land-based convection centre, and plays a fundamental role in the atmospheric transport of latent heat to the higher latitudes. This is particularly significant during the austral summer months when Southern Hemisphere insolation is at a maximum, and the South American Summer Monsoon (SASM) is at its most developed. However, the Pleistocene climate history of the Amazon Basin is comparatively poorly known. Previous indicators of effective moisture have been relatively few in number and widely dispersed, often recording a highly localised signal, with many records also being fragmentary and/or having poor age control. Conversely, marine sediments from the Amazon Fan can circumvent these limitations as they have the potential to record a basin-wide average of past changes in effective moisture within single, continuous sequences that can be radiocarbon dated. Furthermore, high rates of sedimentation have the potential to yield data of a resolution comparable to the ice core records. Radiocarbon-dated δ18O records have been generated from ODP Site 942 on the Amazon Fan. By isolating the shifts in planktonic δ 18O brought about by freshwater-driven changes in salinity over the Amazon Fan (Δδ 18O), it has been possible to monitor past changes in the outflow of the Amazon River, and hence derive a proxy for the effective moisture history of the Amazon Basin. Δδ18O data imply that the Amazon Basin was more arid during the glacial period, relative to the Holocene. This is interpreted to be associated with the glacial-interglacial variation in Southern Hemisphere summer insolation and the associated intensity of the SASM. However through the Last Glacial Interglacial Transition (LGIT), effective moisture levels in the Amazon Basin appear to have co-varied with Antarctic temperature records (implied from the Vostock Ice Core ΔD, based on the timescale of Blunier et al, 1998, Nature, 384, p 739-743). The post

  15. Oil and gas projects in the Western Amazon: threats to wilderness, biodiversity, and indigenous peoples.

    Directory of Open Access Journals (Sweden)

    Matt Finer

    Full Text Available BACKGROUND: The western Amazon is the most biologically rich part of the Amazon basin and is home to a great diversity of indigenous ethnic groups, including some of the world's last uncontacted peoples living in voluntary isolation. Unlike the eastern Brazilian Amazon, it is still a largely intact ecosystem. Underlying this landscape are large reserves of oil and gas, many yet untapped. The growing global demand is leading to unprecedented exploration and development in the region. METHODOLOGY/PRINCIPAL FINDINGS: We synthesized information from government sources to quantify the status of oil development in the western Amazon. National governments delimit specific geographic areas or "blocks" that are zoned for hydrocarbon activities, which they may lease to state and multinational energy companies for exploration and production. About 180 oil and gas blocks now cover approximately 688,000 km(2 of the western Amazon. These blocks overlap the most species-rich part of the Amazon. We also found that many of the blocks overlap indigenous territories, both titled lands and areas utilized by peoples in voluntary isolation. In Ecuador and Peru, oil and gas blocks now cover more than two-thirds of the Amazon. In Bolivia and western Brazil, major exploration activities are set to increase rapidly. CONCLUSIONS/SIGNIFICANCE: Without improved policies, the increasing scope and magnitude of planned extraction means that environmental and social impacts are likely to intensify. We review the most pressing oil- and gas-related conservation policy issues confronting the region. These include the need for regional Strategic Environmental Impact Assessments and the adoption of roadless extraction techniques. We also consider the conflicts where the blocks overlap indigenous peoples' territories.

  16. Oil and gas projects in the Western Amazon: threats to wilderness, biodiversity, and indigenous peoples.

    Science.gov (United States)

    Finer, Matt; Jenkins, Clinton N; Pimm, Stuart L; Keane, Brian; Ross, Carl

    2008-08-13

    The western Amazon is the most biologically rich part of the Amazon basin and is home to a great diversity of indigenous ethnic groups, including some of the world's last uncontacted peoples living in voluntary isolation. Unlike the eastern Brazilian Amazon, it is still a largely intact ecosystem. Underlying this landscape are large reserves of oil and gas, many yet untapped. The growing global demand is leading to unprecedented exploration and development in the region. We synthesized information from government sources to quantify the status of oil development in the western Amazon. National governments delimit specific geographic areas or "blocks" that are zoned for hydrocarbon activities, which they may lease to state and multinational energy companies for exploration and production. About 180 oil and gas blocks now cover approximately 688,000 km(2) of the western Amazon. These blocks overlap the most species-rich part of the Amazon. We also found that many of the blocks overlap indigenous territories, both titled lands and areas utilized by peoples in voluntary isolation. In Ecuador and Peru, oil and gas blocks now cover more than two-thirds of the Amazon. In Bolivia and western Brazil, major exploration activities are set to increase rapidly. Without improved policies, the increasing scope and magnitude of planned extraction means that environmental and social impacts are likely to intensify. We review the most pressing oil- and gas-related conservation policy issues confronting the region. These include the need for regional Strategic Environmental Impact Assessments and the adoption of roadless extraction techniques. We also consider the conflicts where the blocks overlap indigenous peoples' territories.

  17. Hydrogeology of the Western Amazon Aquifer System (WAAS)

    Science.gov (United States)

    Rosário, Fátima Ferreira do; Custodio, Emilio; Silva, Gerson Cardoso da, Jr.

    2016-12-01

    The Western Amazon Aquifer System (WAAS), as defined and proposed in the present work, encompasses an area of about 2.0·106 km2 located in the northwestern portion of South America. Published and unpublished data were used to define WAAS boundaries and main hydrogeologic characteristics. Petroleum industry data, environmental data, and other diverse thematic data were compiled for this study according to the data's origin. The analysis, treatment and integration of available data allowed us to define the WAAS as a multilayered aquifer system comprised of the Tertiary Solimões Aquifer System (SAS) and the Cretaceous Tikuna Aquifer System (TAS). The thick clay-rich basal strata of the SAS appear to confine the TAS. The SAS is widely used for both domestic and industrial purposes, providing good quality freshwater. The TAS has varying water quality: it contains freshwater near its recharge areas in the Sub-Andean fault belt zone, brackish to brine water in the Sub-Andean basins, and salty water in the Solimões Basin (Brazil). The interpretation and conclusions provided by an increasing understanding of the area's hydrogeology resulting from this work made it possible to propose an improved and new WAAS regional hydrogeologic conceptual model with data and descriptions not previously available. Some surprising results have been later confirmed as true by looking at unpublished reports, logs and field notes. Therefore, this work resulted in new findings and settled the basis for future works, especially for the poorly understood TAS.

  18. Placentation in dolphins from the Amazon River Basin

    DEFF Research Database (Denmark)

    da Silva, Vera M F; Carter, Anthony M; Ambrosio, Carlos E

    2007-01-01

    A recent reassessment of the phylogenetic affinities of cetaceans makes it timely to compare their placentation with that of the artiodactyls. We studied the placentae of two sympatric species of dolphin from the Amazon River Basin, representing two distinct families. The umbilical cord branched...

  19. Future of oil and gas development in the western Amazon

    Science.gov (United States)

    Finer, Matt; Babbitt, Bruce; Novoa, Sidney; Ferrarese, Francesco; Eugenio Pappalardo, Salvatore; De Marchi, Massimo; Saucedo, Maria; Kumar, Anjali

    2015-02-01

    The western Amazon is one of the world’s last high-biodiversity wilderness areas, characterized by extraordinary species richness and large tracts of roadless humid tropical forest. It is also home to an active hydrocarbon (oil and gas) sector, characterized by operations in extremely remote areas that require new access routes. Here, we present the first integrated analysis of the hydrocarbon sector and its associated road-building in the western Amazon. Specifically, we document the (a) current panorama, including location and development status of all oil and gas discoveries, of the sector, and (b) current and future scenario of access (i.e. access road versus roadless access) to discoveries. We present an updated 2014 western Amazon hydrocarbon map illustrating that oil and gas blocks now cover 733 414 km2, an area much larger than the US state of Texas, and have been expanding since the last assessment in 2008. In terms of access, we documented 11 examples of the access road model and six examples of roadless access across the region. Finally, we documented 35 confirmed and/or suspected untapped hydrocarbon discoveries across the western Amazon. In the Discussion, we argue that if these reserves must be developed, use of the offshore inland model—a method that strategically avoids the construction of access roads—is crucial to minimizing ecological impacts in one of the most globally important conservation regions.

  20. Tree ring reconstructed rainfall over the southern Amazon Basin

    Science.gov (United States)

    Lopez, Lidio; Stahle, David; Villalba, Ricardo; Torbenson, Max; Feng, Song; Cook, Edward

    2017-07-01

    Moisture sensitive tree ring chronologies of Centrolobium microchaete have been developed from seasonally dry forests in the southern Amazon Basin and used to reconstruct wet season rainfall totals from 1799 to 2012, adding over 150 years of rainfall estimates to the short instrumental record for the region. The reconstruction is correlated with the same atmospheric variables that influence the instrumental measurements of wet season rainfall. Anticyclonic circulation over midlatitude South America promotes equatorward surges of cold and relatively dry extratropical air that converge with warm moist air to form deep convection and heavy rainfall over this sector of the southern Amazon Basin. Interesting droughts and pluvials are reconstructed during the preinstrumental nineteenth and early twentieth centuries, but the tree ring reconstruction suggests that the strong multidecadal variability in instrumental and reconstructed wet season rainfall after 1950 may have been unmatched since 1799.

  1. LBA-ECO LC-07 JERS-1 SAR Wetlands Masks and Land Cover, Amazon Basin: 1995-1996

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides three Amazon Basin wetland image products: (1) a Central Amazon Wetlands Mask, (2) a Central Amazon Wetlands Vegetative-hydrologic Land Cover...

  2. LBA-ECO LC-07 JERS-1 SAR Wetlands Masks and Land Cover, Amazon Basin: 1995-1996

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set provides three Amazon Basin wetland image products: (1) a Central Amazon Wetlands Mask, (2) a Central Amazon Wetlands Vegetative-hydrologic...

  3. Exploring the Geomorphology of the Amazon's Planalto with Imaging Radar: Understanding the Origins of the Modern Amazon Basin

    Science.gov (United States)

    McDonald, K. C.; Campbell, K.; Islam, R.; Azarderakhsh, M.; Cracraft, J.

    2013-12-01

    Amazonia is Earth's most iconic center of biological diversity and endemism and, owing to its contributions to global systems ecology, is arguably Earth's most important terrestrial biome . Amazonia includes a vast landscape of mostly lowland rainforest found in Brazil, Peru, Colombia, Ecuador, Bolivia, and Venezuela. It harbors the world's highest species diversity, the largest fresh-water ecosystem in the world, and contributes substantially to shaping the Earth's atmospheric gasses and oceans and consequently its climate. Despite this global importance, we still have an incomplete understanding of how this biodiversity-rich biome developed over time. Knowing its history is crucially important for understanding how the short and long-term effects of biodiversity loss and climate change will impact the region, and the globe, in the future. Hence, we seek to understand the evolutionary and environmental-ecological history of Amazonia over the past 10 million years through a comparative approach that integrates across the disciplines of systematic biology, population biology, ecosystem structure and function, geology, Earth systems modeling and remote sensing, and paleoenvironmental history. During springtime 2013, the NASA/JPL airborne imaging radar, UAVSAR, conducted airborne studies over many regions of South America including portions of the western Amazon basin. We utilize UAVSAR imagery acquired over the Madre de Dios region of southeastern Peru in an assessment of the underlying geomorphology of the Amazon's planalto, its relationship to the current distribution of vegetation, and its relationship to geologic processes through deep time. In the late Neogene, the Amazonian lowlands comprised either a series of independent basins or a single sedimentary basin. The Amazonian planalto is variously described as either an erosional surface or a surface of deposition. We employ UAVSAR data collections to assess (1) the utility of these high quality imaging radar

  4. Severe convection features in the Amazon Basin: a TRMM-based 15-year evaluation

    Directory of Open Access Journals (Sweden)

    Ana Maria Pereira Nunes

    2016-04-01

    Full Text Available Rainfall in the Amazon Basin is very heterogeneous, mainly because the area encompassed is quite large. Among the systems responsible for rainfall, some stand out as extreme storm events. This study presents a criterion for identifying potentially severe convection in the Amazon region from the Tropical Rainfall Measuring Mission (TRMM database, specifically from Precipitation Features (PF - 1998-2012 - generated and stored by the University of Utah. The seasonal and spatial distributions are similar to distributions of Mesoscale Convective Systems already catalogued in previous studies based on GOES satellite images. The seasons with the highest number of cases are austral spring, winter, and fall. With the Amazon region divided into six subregions and cases accumulated by quarter (JFM, AMJ, JAS, OND the south of the Amazon subregion (SA accounts for the largest number of cases with the OND quarter with higher occurrence and the lowest in AMJ. Different diurnal cycles of potentially severe convection are observed across the region with the more western areas, closer to the Andes, favoring nighttime cases, especially in the austral spring and summer. The diurnal cycle of the number of the most extreme cases is more pronounced than the diurnal cycle when a large collection of deep convection cases are included.

  5. Rickettsial Disease in the Peruvian Amazon Basin.

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    Claudine Kocher

    2016-07-01

    Full Text Available Using a large, passive, clinic-based surveillance program in Iquitos, Peru, we characterized the prevalence of rickettsial infections among undifferentiated febrile cases and obtained evidence of pathogen transmission in potential domestic reservoir contacts and their ectoparasites. Blood specimens from humans and animals were assayed for spotted fever group rickettsiae (SFGR and typhus group rickettsiae (TGR by ELISA and/or PCR; ectoparasites were screened by PCR. Logistic regression was used to determine associations between patient history, demographic characteristics of participants and symptoms, clinical findings and outcome of rickettsial infection. Of the 2,054 enrolled participants, almost 2% showed evidence of seroconversion or a 4-fold rise in antibody titers specific for rickettsiae between acute and convalescent blood samples. Of 190 fleas (Ctenocephalides felis and 60 ticks (Rhipicephalus sanguineus tested, 185 (97.4% and 3 (5%, respectively, were positive for Rickettsia spp. Candidatus Rickettsia asemboensis was identified in 100% and 33% of the fleas and ticks tested, respectively. Collectively, our serologic data indicates that human pathogenic SFGR are present in the Peruvian Amazon and pose a significant risk of infection to individuals exposed to wild, domestic and peri-domestic animals and their ectoparasites.

  6. Discharge simulation in the sub-basins of the Amazon using ORCHIDEE forced by new datasets

    Directory of Open Access Journals (Sweden)

    M. Guimberteau

    2012-03-01

    Full Text Available The aim of this study is to evaluate the ability of the ORCHIDEE land surface model to simulate streamflows over each sub-basin of the Amazon River basin. For this purpose, simulations are performed with a routing module including the influence of floodplains and swamps on river discharge and validated against on-site hydrological measurements collected within the HYBAM observatory over the 1980–2000 period. When forced by the NCC global meteorological dataset, the initial version of ORCHIDEE shows discrepancies with ORE HYBAM measurements with underestimation by 15% of the annual mean streamflow at Óbidos hydrological station. Consequently, several improvements are incrementally added to the initial simulation in order to reduce those discrepancies. First, values of NCC precipitation are substituted by ORE HYBAM daily in-situ rainfall observations from the meteorological services of Amazonian countries, interpolated over the basin. It highly improves the simulated streamflow over the northern and western parts of the basin, whereas streamflow over southern regions becomes overestimated, probably due to the extension of rainy spots that may be exaggerated by our interpolation method, or to an underestimation of simulated evapotranspiration when compared to flux tower measurements. Second, the initial map of maximal fractions of floodplains and swamps which largely underestimates floodplains areas over the main stem of the Amazon River and over the region of Llanos de Moxos in Bolivia, is substituted by a new one with a better agreement with different estimates over the basin. Simulated monthly water height is consequently better represented in ORCHIDEE when compared to Topex/Poseidon measurements over the main stem of the Amazon. Finally, a calibration of the time constant of the floodplain reservoir is performed to adjust the mean simulated seasonal peak flow at Óbidos in agreement with the observations.

  7. LBA-ECO CD-06 Amazon River Basin Land and Stream Drainage Direction Maps

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides high-resolution (~500 m) gridded land and stream drainage direction maps for the Amazon River basin, excluding the Rio Tocantins basin. These...

  8. Origin, transport and deposition of leaf-wax biomarkers in the Amazon Basin and the adjacent Atlantic

    Science.gov (United States)

    Häggi, Christoph; Sawakuchi, André O.; Chiessi, Cristiano M.; Mulitza, Stefan; Mollenhauer, Gesine; Sawakuchi, Henrique O.; Baker, Paul A.; Zabel, Matthias; Schefuß, Enno

    2016-11-01

    Paleoenvironmental studies based on terrigenous biomarker proxies from sediment cores collected close to the mouth of large river systems rely on a proper understanding of the processes controlling origin, transport and deposition of biomarkers. Here, we contribute to the understanding of these processes by analyzing long-chain n-alkanes from the Amazon River system. We use the δD composition of long-chain n-alkanes from river bed sediments from the Amazon River and its major tributaries, as well as marine core-top samples collected off northeastern South America as tracers for different source areas. The δ13C composition of the same compounds is used to differentiate between long-chain n-alkanes from modern forest vegetation and petrogenic organic matter. Our δ13C results show depleted δ13C values (-33 to -36‰) in most samples, indicating a modern forest source for most of the samples. Enriched values (-31 to -33‰) are only found in a few samples poor in organic carbon indicating minor contributions from a fossil petrogenic source. Long-chain n-alkane δD analyses show more depleted values for the western tributaries, the Madeira and Solimões Rivers (-152 to -168‰), while n-alkanes from the lowland tributaries, the Negro, Xingu and Tocantins Rivers (-142 to -154‰), yield more enriched values. The n-alkane δD values thus reflect the mean annual isotopic composition of precipitation, which is most deuterium-depleted in the western Amazon Basin and more enriched in the eastern sector of the basin. Samples from the Amazon estuary show a mixed long-chain n-alkane δD signal from both eastern lowland and western tributaries. Marine core-top samples underlying the Amazon freshwater plume yield δD values similar to those from the Amazon estuary, while core-top samples from outside the plume showed more enriched values. Although the variability in the river bed data precludes quantitative assessment of relative contributions, our results indicate that long

  9. Simulating hydrologic and hydraulic processes throughout the Amazon River Basin

    Science.gov (United States)

    Beighley, R.E.; Eggert, K.G.; Dunne, T.; He, Y.; Gummadi, V.; Verdin, K.L.

    2009-01-01

    Presented here is a model framework based on a land surface topography that can be represented with various degrees of resolution and capable of providing representative channel/floodplain hydraulic characteristics on a daily to hourly scale. The framework integrates two models: (1) a water balance model (WBM) for the vertical fluxes and stores of water in and through the canopy and soil layers based on the conservation of mass and energy, and (2) a routing model for the horizontal routing of surface and subsurface runoff and channel and floodplain waters based on kinematic and diffusion wave methodologies. The WBM is driven by satellite-derived precipitation (TRMM_3B42) and air temperature (MOD08_M3). The model's use of an irregular computational grid is intended to facilitate parallel processing for applications to continental and global scales. Results are presented for the Amazon Basin over the period Jan 2001 through Dec 2005. The model is shown to capture annual runoff totals, annual peaks, seasonal patterns, and daily fluctuations over a range of spatial scales (>1, 000 to Amazon vary by approximately + /− 5 to 10 cm, and the fractional components accounting for these changes are: root zone soil moisture (20%), subsurface water being routed laterally to channels (40%) and channel/floodplain discharge (40%). Annual variability in monthly water storage changes by + /− 2·5 cm is likely due to 0·5 to 1 month variability in the arrival of significant rainfall periods throughout the basin.

  10. Projected increases in the annual flood pulse of the western Amazon

    Science.gov (United States)

    Zulkafli, Zed; Buytaert, Wouter; Manz, Bastian; Veliz Rosas, Claudia; Willems, Patrick; Lavado-Casimiro, Waldo; Guyot, Jean-Loup; Santini, William

    2016-04-01

    The impact of a changing climate on the Amazon basin is a subject of intensive research due to its rich biodiversity and the significant role of rain forest in carbon cycling. Climate change has also direct hydrological impact, and there have been increasing efforts to understand such dynamics at continental and subregional scales such as the scale of the western Amazon. New projections from the Coupled Model Inter- comparison Project Phase 5 (CMIP5) ensemble indicate consistent climatic warming and increasing seasonality of precipitation in the Peruvian Amazon basin. Here we use a distributed land surface model to quantify the potential impact of this change in the climate on the hydrological regime of the river. Using extremes value analysis, historical and future projections of the annual minimum, mean, and maximum river flows are produced for a range of return periods between 1 and 100 years. We show that the RCP 4.5 and 8.5 scenarios of climate change project an increased severity of the wet season flood pulse (7.5% and 12% increases respectively for the 100- year return floods). These findings are in agreement with previously projected increases in high extremes under the Special Report on Emissions Scenarios (SRES) climate projections, and are important to highlight due to the potential consequences on reproductive processes of in-stream species, swamp forest ecology, and socio-economy in the floodplain, amid a growing literature that more strongly emphasises future droughts and their impact on the viability of the rain forest system over the greater Amazonia.

  11. LBA-ECO LC-15 Aerodynamic Roughness Maps of Vegetation Canopies, Amazon Basin: 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set, LBA-ECO LC-15 Aerodynamic Roughness Maps of Vegetation Canopies, Amazon Basin: 2000, provides physical roughness maps of vegetation canopies in the...

  12. LBA-ECO LC-14 Modeled Soil and Plant Water Balance, Amazon Basin, 1995-2001

    Data.gov (United States)

    National Aeronautics and Space Administration — A simple GIS soil-water balance model for the Amazon Basin, called RisQue (Risco de Queimadasa -- Fire Risk), was used to conduct an analysis of spatial and temporal...

  13. LBA-ECO LC-07 Wetland Extent, Vegetation, and Inundation: Lowland Amazon Basin

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides a map of wetland extent, vegetation type, and dual-season flooding state of the entire lowland Amazon basin. The map was derived from mosaics...

  14. LBA-ECO LC-15 NDVI Composite Images of the Amazon Basin: 1999-2000

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides Normalized Difference Vegetation Index (NDVI) composite images of the Amazon Basin for the years 1999-2000 at approximately1-km spatial...

  15. LBA-ECO LC-14 Modeled Soil and Plant Water Balance, Amazon Basin, 1995-2001

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: A simple GIS soil-water balance model for the Amazon Basin, called RisQue (Risco de Queimadasa -- Fire Risk), was used to conduct an analysis of spatial...

  16. LBA-ECO LC-15 Aerodynamic Roughness Maps of Vegetation Canopies, Amazon Basin: 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set provides physical roughness maps of vegetation canopies in the Amazon Basin. The images are estimates of aerodynamic roughness length (Z0)...

  17. LBA-ECO LC-14 Modeled Deforestation Scenarios, Amazon Basin: 2002-2050

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set provides the results of the two modeled scenarios for future patterns of deforestation across the Amazon Basin from 2002 to 2050. This larger...

  18. LBA-ECO LC-14 Modeled Deforestation Scenarios, Amazon Basin: 2002-2050

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides the results of the two modeled scenarios for future patterns of deforestation across the Amazon Basin from 2002 to 2050. This larger defined...

  19. LBA-ECO LC-15 Amazon Basin Aboveground Live Biomass Distribution Map: 1990-2000

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides a single raster image containing the spatial distribution of aboveground live forest biomass of the Amazon basin. This product was derived...

  20. LBA-ECO CD-06 Amazon River Basin Land and Stream Drainage Direction Maps

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set provides high-resolution (~500 m) gridded land and stream drainage direction maps for the Amazon River basin, excluding the Rio Tocantins...

  1. Amazon basin soils: management for continuous crop production.

    Science.gov (United States)

    Sanchez, P A; Bandy, D E; Villachica, J H; Nicholaides, J J

    1982-05-21

    Technology has been developed which permits continuous production of annual crops in some of the acid, infertile soils of the Amazon Basin. Studies in Yurimaguas, Peru, show that three grain crops can be produced annually with appropriate fertilizer inputs. Twenty-one crops have been harvested during the past 8(1/2) years in the same field, with an average annual production of 7.8 tons of grain per hectare. Soil properties are improving with continuous cultivation. The technology has been validated by local farmers, who normally practice shifting cultivation. Economic interpretations indicate large increases in annual family farm income and a high return on the investment of chemical inputs. Other promising land use alternatives include low-input crop production systems, paddy rice production in fertile alluvial soils, and pastures or agroforestry in rolling areas. Stable, continuous food crop production is an attractive alternative to shifting cultivation in humid tropical regions experiencing severe demographic pressures. For each hectare of land managed in a highly productive manner, there may be less need for clearing additional tropical forests to meet food demands.

  2. Lead exposure in indigenous communities of the Amazon basin, Peru.

    Science.gov (United States)

    Anticona, Cynthia; Bergdahl, Ingvar A; Lundh, Thomas; Alegre, Yuri; Sebastian, Miguel San

    2011-12-01

    Since 2006, three studies have reported elevated levels of lead (Pb) among the indigenous population of the Corrientes river, in the Amazon basin of Peru. Due to the large evidence of environmental pollution related to oil exploitation in the area, this activity has been suggested as the source of exposure. This study aimed to evaluate Pb levels in the population and environment of two communities exposed and one community non-exposed to the oil exploitation activity. Blood lead levels (BLL) were determined by the instrument Leadcare. A comparison with the graphite furnace atomic absorption technique was performed in order to validate the Leadcare results. Environmental samples were analyzed by inductively coupled plasma atomic emission spectroscopy. Among 361 capillary samples, the mean BLL was 9.4 μg/dl. Mean BLL of the communities exposed (n=171, x¯=9.5 μg/dl) and non-exposed (n=190, x¯=9.2 μg/dl) to the oil activity were not significantly different. Pb levels in environmental samples were below the maximum permissible levels. The sources of exposure could not be identified. Elevated levels of Pb in the oil-non-exposed community pointed out at other sources not yet clarified. Copyright © 2011 Elsevier GmbH. All rights reserved.

  3. Assessment of Wetland Ecosystem Health in the Yangtze and Amazon River Basins

    Directory of Open Access Journals (Sweden)

    Rui Sun

    2017-03-01

    Full Text Available As “kidneys of the earth”, wetlands play an important role in ameliorating weather conditions, flood storage, and the control and reduction of environmental pollution. With the development of local economies, the wetlands in both the Amazon and Yangtze River Basins have been affected and threatened by human activities, such as urban expansion, reclamation of land from lakes, land degradation, and large-scale agricultural development. It is necessary and important to develop a wetland ecosystem health evaluation model and to quantitatively evaluate the wetland ecosystem health in these two basins. In this paper, GlobeLand30 land cover maps and socio-economic and climate data from 2000 and 2010 were adopted to assess the wetland ecosystem health of the Yangtze and Amazon River Basins on the basis of a pressure-state-response (PSR model. A total of 13 indicators were selected to build the wetland health assessment system. Weights of these indicators and PSR model components, as well as normalized wetland health scores, were assigned and calculated based on the analytic hierarchy process method. The results showed that from 2000 to 2010, the value of the mean wetland ecosystem health index in the Yangtze River Basin decreased from 0.482 to 0.481, while it increased from 0.582 to 0.593 in the Amazon River Basin. This indicated that the average status of wetland ecosystem health in the Amazon River Basin is better than that in the Yangtze River Basin, and that wetland health improved over time in the Amazon River Basin but worsened in the Yangtze River Basin.

  4. Branch xylem density variations across the Amazon Basin

    Directory of Open Access Journals (Sweden)

    S. Patiño

    2009-04-01

    Full Text Available Xylem density is a physical property of wood that varies between individuals, species and environments. It reflects the physiological strategies of trees that lead to growth, survival and reproduction. Measurements of branch xylem density, ρx, were made for 1653 trees representing 598 species, sampled from 87 sites across the Amazon basin. Measured values ranged from 218 kg m−3 for a Cordia sagotii (Boraginaceae from Mountagne de Tortue, French Guiana to 1130 kg m−3 for an Aiouea sp. (Lauraceae from Caxiuana, Central Pará, Brazil. Analysis of variance showed significant differences in average ρx across regions and sampled plots as well as significant differences between families, genera and species. A partitioning of the total variance in the dataset showed that species identity (family, genera and species accounted for 33% with environment (geographic location and plot accounting for an additional 26%; the remaining "residual" variance accounted for 41% of the total variance. Variations in plot means, were, however, not only accountable by differences in species composition because xylem density of the most widely distributed species in our dataset varied systematically from plot to plot. Thus, as well as having a genetic component, branch xylem density is a plastic trait that, for any given species, varies according to where the tree is growing in a predictable manner. Within the analysed taxa, exceptions to this general rule seem to be pioneer species belonging for example to the Urticaceae whose branch xylem density is more constrained than most species sampled in this study. These patterns of variation of branch xylem density across Amazonia suggest a large functional diversity amongst Amazonian trees which is not well understood.

  5. Branch xylem density variations across the Amazon Basin

    Science.gov (United States)

    Patiño, S.; Lloyd, J.; Paiva, R.; Baker, T. R.; Quesada, C. A.; Mercado, L. M.; Schmerler, J.; Schwarz, M.; Santos, A. J. B.; Aguilar, A.; Czimczik, C. I.; Gallo, J.; Horna, V.; Hoyos, E. J.; Jimenez, E. M.; Palomino, W.; Peacock, J.; Peña-Cruz, A.; Sarmiento, C.; Sota, A.; Turriago, J. D.; Villanueva, B.; Vitzthum, P.; Alvarez, E.; Arroyo, L.; Baraloto, C.; Bonal, D.; Chave, J.; Costa, A. C. L.; Herrera, R.; Higuchi, N.; Killeen, T.; Leal, E.; Luizão, F.; Meir, P.; Monteagudo, A.; Neil, D.; Núñez-Vargas, P.; Peñuela, M. C.; Pitman, N.; Priante Filho, N.; Prieto, A.; Panfil, S. N.; Rudas, A.; Salomão, R.; Silva, N.; Silveira, M.; Soares Dealmeida, S.; Torres-Lezama, A.; Vásquez-Martínez, R.; Vieira, I.; Malhi, Y.; Phillips, O. L.

    2009-04-01

    Xylem density is a physical property of wood that varies between individuals, species and environments. It reflects the physiological strategies of trees that lead to growth, survival and reproduction. Measurements of branch xylem density, ρx, were made for 1653 trees representing 598 species, sampled from 87 sites across the Amazon basin. Measured values ranged from 218 kg m-3 for a Cordia sagotii (Boraginaceae) from Mountagne de Tortue, French Guiana to 1130 kg m-3 for an Aiouea sp. (Lauraceae) from Caxiuana, Central Pará, Brazil. Analysis of variance showed significant differences in average ρx across regions and sampled plots as well as significant differences between families, genera and species. A partitioning of the total variance in the dataset showed that species identity (family, genera and species) accounted for 33% with environment (geographic location and plot) accounting for an additional 26%; the remaining "residual" variance accounted for 41% of the total variance. Variations in plot means, were, however, not only accountable by differences in species composition because xylem density of the most widely distributed species in our dataset varied systematically from plot to plot. Thus, as well as having a genetic component, branch xylem density is a plastic trait that, for any given species, varies according to where the tree is growing in a predictable manner. Within the analysed taxa, exceptions to this general rule seem to be pioneer species belonging for example to the Urticaceae whose branch xylem density is more constrained than most species sampled in this study. These patterns of variation of branch xylem density across Amazonia suggest a large functional diversity amongst Amazonian trees which is not well understood.

  6. Applications of GNSS data for hydrological studies in the Amazon basin.

    Science.gov (United States)

    Moreira, D.; Perosanz, F.; Calmant, S.; Santos, A.; Silva, J.; Ramillien, G.; Rotunno, O.; Seyler, F.; Monteiro, A.; Shum, C. K.

    2012-04-01

    Applications of GNSS data is constantly being used in hydrology. The key applications are the levelling of hydrological gauge stations and characterization of river's longitudinal profiles, these information are required to develop hydrological and hydrodynamic studies and to evaluate the quality of data obtained through space altimetry techniques. Some factors illustrate the challenge of establishing quality altimetry data from a GNSS receivers to obtain rivers profiles in Amazon Basin. GNSS reference network is sparse, the distance between survey points and reference stations is large, rivers have an extension of several thousands of kilometers. All these factors contribute in limiting the efficiency of classical techniques of GNSS data processing like double difference. In addition the Amazon Basin are strongly affected by charge effects, mainly caused by the hydrological cycle of this basin. These effects can produce a variation of about 10 cm in amplitude of vertical coordinates In the present work we use the Gins-PC software developed at CNES / GRGS. We discuss the capability of kinematic processing strategy implemented in GINS-PC in use GNSS data to calculate river's longitudinal profiles in the Amazon Basin. The profiles will be processed using data obtained from GPS receivers on boarding boats along the rivers of Amazon Basin such as Negro river, Madeira river and Amazon/Solimões river. For this purpose, field campaigns were conducted between 2005 and 2011 by ANA ( Brazilian National Water Agency), CPRM (Brazilian Geologic Survey), IRD (French Institute of Research by Development), Hybam ( Hydrology of Amazon Basin), PROSUL (Research project by CNPQ/UFRJ) and FOAM (From Ocean to inland waters Altimetry Monitoring) river section project. The profiles are also used to levelling some gauge stations in Amazon Basin and gauge data are used to obtain a temporal variation of these profiles. GPS data are processed using a Double-Difference and a PPP strategy. The

  7. Low prevalence of hepatitis B virus, hepatitis D virus and hepatitis C virus among patients with human immunodeficiency virus or acquired immunodeficiency syndrome in the Brazilian Amazon basin

    OpenAIRE

    Braga,Wornei Silva Miranda; Castilho,Márcia da Costa; Santos,Isabelle Cristina Vale dos; Moura,Marco Antônio Sabóia; Segurado,Aluisio Cotrim

    2006-01-01

    Comorbidities in human immunodeficiency virus infection are of great interest due to their association with unfavorable outcomes and failure of antiretroviral therapy. This study evaluated the prevalence of coinfection by human immunodeficiency virus and viral hepatitis in an endemic area for hepatitis B in the Western Amazon basin. Serological markers for hepatitis B virus, hepatitis C virus and hepatitis D virus were tested in a consecutive sample of all patients referred for treatment of h...

  8. Exploring the Geomorphology of the Amazon's Planalto and Understanding the Origin of the Modern Amazon Basin with Imaging Radar:

    Science.gov (United States)

    Islam, R.; McDonald, K. C.; Azarderakhsh, M.; Campbell, K.; Cracraft, J.; Carnaval, A. C.

    2015-12-01

    The Amazon basin is a biodiversity biome and plays a significant role into shaping the earth's climate, ocean and atmospheric gases. Understanding the history of the formation of the basin is essential to our understanding of the region's biodiversity loss and response to climate change. Ancient River channels in lowland Amazonia exhibit right angle branching structures as well as intricately intertwined channels. Past research has attributed these characteristic as a result of subsurface faults but makes it difficult to validate this augment due to dense vegetation and sedimentation. We seek to employ remote sensing techniques for examining geomorphological features and the relationship to evolutionary processes that shaped biodiversity in the modern Amazon River Basin. We utilize UAVSAR imagery gathered from the NASA/JPL airborne imaging radar over the Planalto, in the Madre de Dios region of Southeastern Peru in an assessment of the underlying geomorphology, its relationship to the current distribution of vegetation, and geologic processes through deep time. In the late Neogene, the Amazonian lowlands comprised either a series of independent basins or a single sedimentary basin. The Amazonian Planalto is variously described as either erosional surface or a surface of deposition. We employ UAVSAR data collection to assess (1) the utility of these radar data for use in identifying associated geomorphologic features, and (2) UAVSAR's utility in aiding interpretation of ALOS PALSAR and STRM datasets to support a basin-wide characterization. We derive maps of river networks using a canny based edge detection method applied on the UAVSAR backscatter images. We develop an algorithm, which separates the river networks into various catchments based on connected component and then calculates angles at each branch point. We then assess distribution of right angle branching structure throughout the entire region. The results of the analysis will have a major impact on

  9. Application of support vector regression (SVR) for stream flow prediction on the Amazon basin

    CSIR Research Space (South Africa)

    Du Toit, Melise

    2016-10-01

    Full Text Available regression technique is used in this study to analyse historical stream flow occurrences and predict stream flow values for the Amazon basin. Up to twelve month predictions are made and the coefficient of determination and root-mean-square error are used...

  10. LBA-ECO LC-15 Vegetation Cover Types from MODIS, 1-km, Amazon Basin: 2000-2001

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains proportional estimates for the vegetative cover types of woody vegetation, herbaceous vegetation, and bare ground over the Amazon Basin for...

  11. Annual Carbon Emissions from Deforestation in the Amazon Basin between 2000 and 2010.

    Science.gov (United States)

    Song, Xiao-Peng; Huang, Chengquan; Saatchi, Sassan S; Hansen, Matthew C; Townshend, John R

    2015-01-01

    Reducing emissions from deforestation and forest degradation (REDD+) is considered one of the most cost-effective strategies for mitigating climate change. However, historical deforestation and emission rates-critical inputs for setting reference emission levels for REDD+-are poorly understood. Here we use multi-source, time-series satellite data to quantify carbon emissions from deforestation in the Amazon basin on a year-to-year basis between 2000 and 2010. We first derive annual deforestation indicators by using the Moderate Resolution Imaging Spectroradiometer Vegetation Continuous Fields (MODIS VCF) product. MODIS indicators are calibrated by using a large sample of Landsat data to generate accurate deforestation rates, which are subsequently combined with a spatially explicit biomass dataset to calculate committed annual carbon emissions. Across the study area, the average deforestation and associated carbon emissions were estimated to be 1.59 ± 0.25 M ha•yr(-1) and 0.18 ± 0.07 Pg C•yr(-1) respectively, with substantially different trends and inter-annual variability in different regions. Deforestation in the Brazilian Amazon increased between 2001 and 2004 and declined substantially afterwards, whereas deforestation in the Bolivian Amazon, the Colombian Amazon, and the Peruvian Amazon increased over the study period. The average carbon density of lost forests after 2005 was 130 Mg C•ha(-1), ~11% lower than the average carbon density of remaining forests in year 2010 (144 Mg C•ha(-1)). Moreover, the average carbon density of cleared forests increased at a rate of 7 Mg C•ha(-1)•yr(-1) from 2005 to 2010, suggesting that deforestation has been progressively encroaching into high-biomass lands in the Amazon basin. Spatially explicit, annual deforestation and emission estimates like the ones derived in this study are useful for setting baselines for REDD+ and other emission mitigation programs, and for evaluating the performance of such efforts.

  12. Chlorococcales (Algee: Chlorophyceae found in aquatic environments of the Colombian Amazon basin Chlorococcales (Algee: Chlorophyceae found in aquatic environments of the Colombian Amazon basin

    Directory of Open Access Journals (Sweden)

    Núñez Avellaneda Marcela

    1998-06-01

    Full Text Available Ten taxa of algae belonging to the order Chlorococcales are recorded for the first time from the Colombian Amazon basin. Two of these, Nephrocytium limneticum and Sorastrum americanum var. americanum, are recorded for the first time in Colombia.Se registran por primera vez para la Amazonia colombiana 10 taxones de Chlorococcales del fitoplancton y ticoplancton encontrados en algunos lagos del río Amazonas y del río Cotuhé, afluente del río Putumayo. Nephrocytium limneticum y Sorastrum americanum varo americanum son primeros registros para Colombia.

  13. Basin and Range Province, Western US, USGS Grids #4

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These grid files were used to produce gravity and basin depth maps of the Basin and Range Province, western United States. The maps show gravity values and modeled...

  14. Basin and Range Province, Western US, USGS Grids #5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These grid files were used to produce gravity and basin depth maps of the Basin and Range Province, western United States. The maps show gravity values and modeled...

  15. Basin and Range Province, Western US, USGS Grids #3

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These grid files were used to produce gravity and basin depth maps of the Basin and Range Province, western United States. The maps show gravity values and modeled...

  16. Basin and Range Province, Western US, USGS Grids, #1

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These grid files were used to produce gravity and basin depth maps of the Basin and Range Province, western United States. The maps show gravity values and modeled...

  17. The cycle of biogenic sulfur compounds over the Amazon Basin. I - Dry season

    Science.gov (United States)

    Andreae, M. O.; Andreae, T. W.

    1988-01-01

    The concentrations of SO2, methylmercaptan, dimethylsulfide, H2S, aerosol sulfate, and methanesulfonate over the Amazon Basin during the July/August dry season were determined from samples collected by the NASA research aircraft. The results indicate that biogenic emissions represent an important, if not the dominant, source of sulfur to the atmosphere over Amazonia. Per unit area, the wet continental tropics appear to have about the same reduced sulfur emission flux as the oceanic area average (about 6 nmol/sq m per min), consistent with the fact that the aerosol sulfate concentration over the Amazon Basin is similar to the excess sulfate levels over the remote oceans. However, since the wet tropical continents represent only about 3 percent of the earth's surface, their global contribution is modest; it is also small relative to the anthropogenic emissions from fossil fuel burning.

  18. Mercury levels and human health in the Amazon Basin.

    Science.gov (United States)

    Dórea, José G; Marques, Rejane C

    2016-07-01

    Environmental mercury in the Amazon mostly originates from geochemical sources with some from artisanal gold mining (AGM). Geochemical-originated methylmercury (MeHg) reaches the aquatic food chain, ending up in fish. Inorganic Hg used in AGM is responsible for localised environmental contamination and occupational exposure of adults. In addition to this, iatrogenic ethylmercury (EtHg) derived from Thimerosal-containing vaccines (TCVs) exposes immunised infants. To understand Hg exposure in the Amazon in relation to environmental fish-MeHg exposure, occupational AGM activities and low-doses of TCV-EtHg. Medline and Thomson-Reuter Web of Science were searched to retrieve and select papers addressing Hg exposure and human health. Environmental-Hg studies addressed health effects associated with birth weight, infant linear growth and neurodevelopment, while, in adults, environmental and occupational studies addressed immune and neurological issues. No widespread clinical toxicity was reported due to fish-MeHg. However, mixed results associated with Hg exposure can be found. Reducing children's exposure to EtHg is possible using Thimerosal-free vaccines, but it is difficult to interfere with fish consumption without consequences to riverine subsistence populations. Policies to diminish Hg exposure should focus on controlling and/or curbing widespread use of Hg (in gold amalgamation) and promotion of Thimerosal-free vaccines for pregnant women and young children.

  19. Use of GNSS Data for Hydrological Surveys in the Amazon Basin

    Science.gov (United States)

    Medeiros Moreira, Daniel; Calmant, Stephane; Perosanz, Félix; Rotunno, Otto; Santos da Silva, Joecila; Santos, Andre

    2016-04-01

    GNSS data are constantly being used in hydrology. The key applications are the levelling of hydrological gauge stations, that of ADCP profiles for discharge and bathymetry of the cross-sections, and characterization of river's longitudinal slope of the free . These information are required to develop hydrological and hydrodynamic studies and to assess the quality of water level data obtained through space altimetry techniques. Establishing quality altimetry data from GNSS receivers to obtain gauge levelling and rivers profiles in the Amazon Basin is challenging. The GNSS reference network is sparse, the distance between survey points and reference stations is large, the major part of the basin can be only accessed by boat and rivers can have an extension of several thousands of kilometres. All these factors limit the efficiency of classical techniques of GNSS data processing like those based on double differences (DD). In addition, the Amazon Basin is strongly affected by loading effects, mainly caused by the hydrological cycle. In this basin, vertical displacements of these effects can reach more than 10 cm of amplitude. In the present work, we discuss the capability of calculating thousands of kilometres long altimetric profiles along the major rivers of the Amazon basin. GNSS data coming from receivers installed on-board boats are used together with GNSS stations fixed on gauges. First, differential techniques implemented in the GINS-PC software developed at the CNES-CLS IGS AC are used. These results are compared to those obtained with the Precise Point Position (PPP) technique. The impacts of fixing ambiguities to integer values in PPP technique are discussed as the use of Glonass data. We point on the specific corrections and cautions that are necessary during the data collection and the data processing. The accuracy of the profiles is assessed by comparing the results with fix points at gauge stations. The base application of the method is to enable fast

  20. Evaluation of last extreme drought events in Amazon basin using remotely sensing data

    Science.gov (United States)

    Panisset, Jéssica S.; Gouveia, Célia M.; Libonati, Renata; Peres, Leonardo; Machado-Silva, Fausto; França, Daniela A.; França, José R. A.

    2017-04-01

    Amazon basin has experienced several intense droughts among which were highlighted last recent ones in 2005 and 2010. Climate models suggest these events will be even more frequent due to higher concentration of greenhouse gases that are also driven forward by alteration in forest dynamics. Environmental and social impacts demand to identify these intense droughts and the behavior of climate parameters that affect vegetation. This present study also identifies a recent intense drought in Amazon basin during 2015. Meteorological parameters and vegetation indices suggest this event was the most severe already registered in the region. We have used land surface temperature (LST), vegetation indices, rainfall and shortwave radiation from 2000 to 2015 to analyze and compare droughts of 2005, 2010 and 2015. Our results show singularities among the three climate extreme events. The austral winter was the most affected season in 2005 and 2010, but not in 2015 when austral summer presented extreme conditions. Precipitation indicates epicenter of 2005 in west Amazon corroborating with previous studies. In 2010, the west region was strongly affected again together with the northwest and the southeast areas. However, 2015 epicenters were concentrated in the east of the basin. In 2015, shortwave radiation has exceeded the maximum values of 2005 and temperature the maximum value of 2010. Vegetation indices have shown positive and negative anomalies. Despite of heterogenous response of Amazon forest to drought, hybrid vegetation indices using NDVI (Normalized Difference Vegetation Index) and LST highlights the exceptionality of 2015 drought episode that exhibits higher vegetation water stress than the cases of 2010 and 2005. Finally, this work has shown how meteorological parameters influence droughts and the effects on vegetation in Amazon basin. Complexity of climate, ecosystem heterogeneity and high diversity of Amazon forest are response by idiosyncrasies of each drought. All

  1. First record of Annonaceae wood for the Neogene of South America, Amazon Basin, Brazil

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    Emilio Alberto Amaral Soares

    Full Text Available ABSTRACT: The relief of the regions of Manaus and Itacoatiara, Central Amazon, is supported by Neogene siliciclastic rocks, bounded at the base and top by lateritic paleosols and covered by quaternary sedimentary deposits from the Solimões-Amazon river system. This unit is informally assigned to the Novo Remanso Formation, consists of usually reddish and ferruginized sandstones, conglomerates and pelites, with few identified fossil records, a fact that has hindered its stratigraphic position, and the paleoenvironmental reconstruction of the last phase of the Amazon Basin settling. This study describes, for the first time, the occurrence of fossil wood in outcroppings of the left bank of the Amazon River, where anatomical and morphological data has enabled its characterization to the species level. Thus, the data marks the record of the Annonaceae in South America, as well as the depositional processes related to incorporation of organic material in the sandy layer and the fossilization processes that allowed its preservation. In an unprecedented way, this study has described Duguetiaxylon amazonicum nov. gen and sp. and provided information on the anatomical and systematic character, as well as data on plant-insect interaction, and a better understanding of the family.

  2. Mapping large-scale river flow hydraulics in the Amazon Basin

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    Getirana, Augusto C. V.; Paiva, Rodrigo C. D.

    2013-05-01

    Research on actual requirements for a numerically consistent representation of flow dynamics in large-scale river-flood models are needed to improve both modeling performance and computational efficiency. Still, regional- and global-scale characterizations of river hydrodynamics are absent. A first attempt to map river hydrodynamics in the Amazon Basin is presented. Flood wave type maps at 0.25° spatial resolution are derived from a classification method based on the analysis of Saint-Venant equation terms. Global river geometry data sets derived from both digital elevation models and empirical equations supported by stream gauge observations are used as input variables. Errors of input variables are estimated, and a sensitivity analysis is performed. Results show that 64.5% of rivers (headwaters and high-slope rivers) can be represented by the kinematic wave (KI), 34.5% (main Amazon tributaries, low slope, and wetland regions) by the diffusive wave (DF), and 1% (lower Amazon) by the full Saint-Venant equations (SV). In a rigorous scenario, i.e., a case where the most restricted classification of each grid cell is considered, ˜33% is classified as KI, ˜62% as DF, and ˜5% as SV. Most of the basin presents subcritical flow with very low Froude number (Fr), while the Andean region is dominated by larger Fr values and supercritical flow can be found. According to our evaluation mostly based on in situ data, the map has a percentage of detection of 83.4%.

  3. Quantifying Changes in Ecosystem Goods and Services From Land-use Change in the Amazon Basin

    Science.gov (United States)

    Zaks, D. P.; Foley, J. A.

    2007-12-01

    The Amazon basin delivers a wide array of ecosystem goods and services to recipients at local, regional and global scales. As an increasing amount of land is converted from natural vegetation to cropland, pasture, biofuel and timber production, the social, economics and biophysical changes have yet to be fully quantified across. There are inherent trade-offs of these goods and services with changes in land-use that occur across scales. Here, we begin to calculate the impact of land-use changes for commodity production across the Amazon and identify user groups and their changing levels of ecosystem services. Future synthesis work will integrate studies completed under the auspices of the Large Biosphere Atmosphere Experiment in Amazonia (LBA) with a next- generation biosphere model, similar to IBIS. Ecosystem services such as carbon sequestration, water quality / quantity, climate regulation and health will be considered. This work aims to better the understanding of the relationship between the biophysical environment and the sociosphere by using economic and statistical data on commodity production and trade to deliver spatially explicit estimates of the changes in ecosystem goods and services across the Amazon basin.

  4. Hepatitis D virus infection in the Western Brazilian Amazon - far from a vanishing disease

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    Wornei Silva Miranda Braga

    2012-12-01

    Full Text Available INTRODUCTION: A decline in hepatitis D virus (HDV occurrence was described in Europe and Asia. We estimated HDV prevalence in the Brazilian Amazon following hepatitis B vaccination. METHODS: This is a cross-sectional survey of HDV measured by total antibodies to HDV (anti-HD T. RESULTS: HDV prevalence was 41.9% whiting HBsAg carries and was associated with age (PR = 1.96; 95% CI 1.12-3.42; p = 0.01, hepatitis B virus (HBV infection (PR = 4.38; 95% CI 3.12-6.13; p < 0.001, and clinical hepatitis (PR =1.44; 95% CI 1.03-2.00; p = 0.03. Risk factors were related to HDV biology, clinical or demographic aspects such as underlying HBV infection, clinical hepatitis and age. CONCLUSIONS: Our study demonstrated that HDV infection continues to be an important health issue in the Brazilian Amazon and that the implementation of the HBV vaccination in rural Lábrea had little or no impact on the spread of HDV. This shows that HDV has not yet disappeared from HBV hyperendemic areas and reminding that it is far from being a vanishing disease in the Amazon basin.

  5. Water Balance in the Amazon Basin from a Land Surface Model Ensemble

    Science.gov (United States)

    Getirana, Augusto C. V.; Dutra, Emanuel; Guimberteau, Matthieu; Kam, Jonghun; Li, Hong-Yi; Decharme, Bertrand; Zhang, Zhengqiu; Ducharne, Agnes; Boone, Aaron; Balsamo, Gianpaolo; hide

    2014-01-01

    Despite recent advances in land surfacemodeling and remote sensing, estimates of the global water budget are still fairly uncertain. This study aims to evaluate the water budget of the Amazon basin based on several state-ofthe- art land surface model (LSM) outputs. Water budget variables (terrestrial water storage TWS, evapotranspiration ET, surface runoff R, and base flow B) are evaluated at the basin scale using both remote sensing and in situ data. Meteorological forcings at a 3-hourly time step and 18 spatial resolution were used to run 14 LSMs. Precipitation datasets that have been rescaled to matchmonthly Global Precipitation Climatology Project (GPCP) andGlobal Precipitation Climatology Centre (GPCC) datasets and the daily Hydrologie du Bassin de l'Amazone (HYBAM) dataset were used to perform three experiments. The Hydrological Modeling and Analysis Platform (HyMAP) river routing scheme was forced with R and B and simulated discharges are compared against observations at 165 gauges. Simulated ET and TWS are compared against FLUXNET and MOD16A2 evapotranspiration datasets andGravity Recovery and ClimateExperiment (GRACE)TWSestimates in two subcatchments of main tributaries (Madeira and Negro Rivers).At the basin scale, simulated ET ranges from 2.39 to 3.26 mm day(exp -1) and a low spatial correlation between ET and precipitation indicates that evapotranspiration does not depend on water availability over most of the basin. Results also show that other simulated water budget components vary significantly as a function of both the LSM and precipitation dataset, but simulated TWS generally agrees with GRACE estimates at the basin scale. The best water budget simulations resulted from experiments using HYBAM, mostly explained by a denser rainfall gauge network and the rescaling at a finer temporal scale.

  6. Neogene vegetation development in the Amazon Basin: evidence from marine well-2, Foz do Amazonas (Brazil)

    Science.gov (United States)

    Bogota-Angel, Raul; Chemale Junior, Farid; Davila, Roberto; Soares, Emilson; Pinto, Ricardo; Do Carmo, Dermeval; Hoorn, Carina

    2014-05-01

    Origen and development of the highly diverse Amazon tropical forest has mostly been inferred from continental sites. However, sediment records in the marine Foz do Amazonas Basin can provide important information to better understand the influence of the Andes uplift and climate change on its plant biomes evolution since the Neogene. Sediment analyses of samples from BP-Petrobras well 1 and 2, drilled in the Amazon Fan, allowed to infer the onset of the transcontinental Amazon river and the fan phase during the middle to late Miocene (c. 10.5 Ma). As part of the CLIMAMAZON research programme we performed pollen analysis on the 10.5 to 0.4 Ma time interval. 76 ditch cutting samples of the upper 4165 m sediments of well 2 permitted us to infer changes in floral composition in the Amazon Basin. The palynological spectra across this interval (nannofossil based age model) include pollen, fern spores, dinocysts and foram lignings. When possible pollen and fern spores were grouped in four vegetation types: estuarine, tropical, mountain forest and high mountain open treeless vegetation. Pollen is generally corroded and reflects the effects of sediment transportation while reworked material is also common. Good pollen producers such as Poaceae, Asteraceae and Cyperaceae are common and reflect indistinctive vegetation types particularly those associated to riverine systems. Rhizophora/Zonocostites spp. indicate "close-distance" mangrove development. Tropical forest biomes are represented by pollen that resemble Moraceae-Urticaceae, Melastomataceae-Combretaceae, Sapotaceae, Alchornea, Euphorbiaceae, Rubiaceae, Bignoniaceae, Mauritia and Arecaceae. Myrica, and particularly sporadic occurrences of fossil fern spores like Lophosoria, and Cyathea suggest the development of a moist Andean forest in areas above 1000 m. First indicators of high altitudes appear in the last part of late Miocene with taxa associated to current Valeriana and particularly Polylepis, a neotropical taxon

  7. Modeling investigation of light-absorbing aerosols in the Amazon Basin during the wet season

    Directory of Open Access Journals (Sweden)

    Q. Wang

    2016-11-01

    Full Text Available We use a global chemical transport model (GEOS-Chem to interpret observed light-absorbing aerosols in Amazonia during the wet season. Observed aerosol properties, including black carbon (BC concentration and light absorption, at the Amazon Tall Tower Observatory (ATTO site in the central Amazon have relatively low background levels but frequently show high peaks during the study period of January–April 2014. With daily temporal resolution for open fire emissions and modified aerosol optical properties, our model successfully captures the observed variation in fine/coarse aerosol and BC concentrations as well as aerosol light absorption and its wavelength dependence over the Amazon Basin. The source attribution in the model indicates the important influence of open fire on the observed variances of aerosol concentrations and absorption, mainly from regional sources (northern South America and from northern Africa. The contribution of open fires from these two regions is comparable, with the latter becoming more important in the late wet season. The analysis of correlation and enhancement ratios of BC versus CO suggests transport times of < 3 days for regional fires and  ∼  11 days for African plumes arriving at ATTO during the wet season. The model performance of long-range transport of African plumes is also evaluated with observations from AERONET, MODIS, and CALIOP. Simulated absorption aerosol optical depth (AAOD averaged over the wet season is lower than 0.0015 over the central Amazon, including the ATTO site. We find that more than 50 % of total absorption at 550 nm is from BC, except for the northeastern Amazon and the Guianas, where the influence of dust becomes significant (up to 35 %. The brown carbon contribution is generally between 20 and 30 %. The distribution of absorption Ångström exponents (AAE suggests more influence from fossil fuel combustion in the southern part of the basin (AAE  ∼  1 but more

  8. Surface Radiative Fluxes from GOES-E over the Amazon Basin: Model Comparison

    Science.gov (United States)

    Ceballos, J. C.; Pinker, R. T.; Pereira, E. B.; Martins, F. R.; Kato, H.; de Miranda, R. M.; Wonsick, M.

    2006-12-01

    In this study reported are results from an algorithm intercomparison initiative aimed at the development of improved estimates of surface radiative fluxes from satellite observations over the Amazon Basin. Three algorithms are used: (UMD-SRB, University of Maryland; GL1.2, INPE, Brazil; and Brasil-SR, INPE and University of Santa Catarina, Brazil). The algorithms are physically based, yet differ in their implementation and the way they address issues specific to this region, such as aerosols from biomass burning. Two fifteen day periods in 2005 were selected representing the rainy and dry seasons. The same satellite observations from GOES E were used by all the models. Ground truth from existing stations in the Amazon as well as from a new solar monitoring network of high quality have been used in evaluation. Using daily mean values for the March rainy season, it was found that: 1) the Brasil-SR and UMD-SRB estimates bear a close resemblance; 2) higher irradiances for Petrolina (semi-arid region in Northeast Brazil) are best described by the UMD-SRB and Brasil-SR, probably due to better assessment of water vapor column and absorption parameterization; 3) the GL1.2 results shows a systematic deviation, underestimating daily mean by about 20 Wm-2, but have lower dispersion than UMD-SRB or Brasil-SR; 4) irradiance interval 180 < E < 250 Wm-2 seems better described by GL1.2. This last behavior may be related to better assessment of cloudiness under partial coverage situations. September is characterized by intensive biomass burning in several Brazilian regions, particularly in the Amazon. The Northeast region is not affected by aerosols and estimates from all three models are in close agreement and have similar characteristics to those of March. For the Amazon sites: 1) lower irradiances (for overcast days) are correctly assessed; 2) UMD-SRB and Brasil-SR overestimate solar radiation, especially for higher irradiances (lower cloudiness); 3) GL1.2 model does not include

  9. Testing conceptual and physically based soil hydrology schemes against observations for the Amazon Basin

    Science.gov (United States)

    Guimberteau, M.; Ducharne, A.; Ciais, P.; Boisier, J. P.; Peng, S.; De Weirdt, M.; Verbeeck, H.

    2014-06-01

    This study analyzes the performance of the two soil hydrology schemes of the land surface model ORCHIDEE in estimating Amazonian hydrology and phenology for five major sub-basins (Xingu, Tapajós, Madeira, Solimões and Negro), during the 29-year period 1980-2008. A simple 2-layer scheme with a bucket topped by an evaporative layer is compared to an 11-layer diffusion scheme. The soil schemes are coupled with a river routing module and a process model of plant physiology, phenology and carbon dynamics. The simulated water budget and vegetation functioning components are compared with several data sets at sub-basin scale. The use of the 11-layer soil diffusion scheme does not significantly change the Amazonian water budget simulation when compared to the 2-layer soil scheme (+3.1 and -3.0% in evapotranspiration and river discharge, respectively). However, the higher water-holding capacity of the soil and the physically based representation of runoff and drainage in the 11-layer soil diffusion scheme result in more dynamic soil water storage variation and improved simulation of the total terrestrial water storage when compared to GRACE satellite estimates. The greater soil water storage within the 11-layer scheme also results in increased dry-season evapotranspiration (+0.5 mm d-1, +17%) and improves river discharge simulation in the southeastern sub-basins such as the Xingu. Evapotranspiration over this sub-basin is sustained during the whole dry season with the 11-layer soil diffusion scheme, whereas the 2-layer scheme limits it after only 2 dry months. Lower plant drought stress simulated by the 11-layer soil diffusion scheme leads to better simulation of the seasonal cycle of photosynthesis (GPP) when compared to a GPP data-driven model based on eddy covariance and satellite greenness measurements. A dry-season length between 4 and 7 months over the entire Amazon Basin is found to be critical in distinguishing differences in hydrological feedbacks between the

  10. A new species of the armored catfish Parotocinclus (Loricariidae: Hypoptopomatinae, from the Amazon basin in Colombia

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    Pablo Lehmann A.

    Full Text Available A new species of hypoptopomatine cascudinho is described from a creek tributary to the Amazon River in Leticia, Amazonas Departament, Colombia. The new species of Parotocinclus is distinguished from congeners from northeastern to southeastern Brazilian rivers in having the cheek canal plate elongated posteriorly on the ventral surface of head and contacting the cleithrum. It is diagnosed from P. collinsae (Essequibo River basin, Guiana and P. halbothi (rio Trombetas basin, Brazil and Marowijne River, Suriname, by having a triangular patch of dark pigmentation on the anterior portion of the dorsal-fin membrane, by the absence of unicuspid accessory teeth on both the premaxilla and dentary, and by having a Y-shaped light mark on the snout. The new species of Parotocinclus is distinguished from all remaining congeners by having a pigmentation pattern consisting of conspicuous dark dots smaller than a pupil diameter, broadly distributed dorsally and ventrally.

  11. Amazon dams and waterways: Brazil's Tapajós Basin plans.

    Science.gov (United States)

    Fearnside, Philip M

    2015-09-01

    Brazil plans to build 43 "large" dams (>30 MW) in the Tapajós Basin, ten of which are priorities for completion by 2022. Impacts include flooding indigenous lands and conservation units. The Tapajós River and two tributaries (the Juruena and Teles Pires Rivers) are also the focus of plans for waterways to transport soybeans from Mato Grosso to ports on the Amazon River. Dams would allow barges to pass rapids and waterfalls. The waterway plans require dams in a continuous chain, including the Chacorão Dam that would flood 18,700 ha of the Munduruku Indigenous Land. Protections in Brazil's constitution and legislation and in international conventions are easily neutralized through application of "security suspensions," as has already occurred during licensing of several dams currently under construction in the Tapajós Basin. Few are aware of "security suspensions," resulting in little impetus to change these laws.

  12. Assessment of climate change impacts on streamflow dynamics in the headwaters of the Amazon River basin

    Science.gov (United States)

    Yoon, Y.; Beighley, E.

    2015-12-01

    The Amazon River basin is the largest watershed in the world containing thousands of tributaries. Although the mainstream and its larger tributaries have been the focus on much research, there has been few studies focused on the hydrodynamics of smaller rivers in the foothills of the Andes Mountains. These smaller rivers are of particular importance for the fishery industry because fish migrate up these headwater rivers to spawn. During the rainy season, fish wait for storm event to increase water depths to a sufficient level for their passage. Understanding how streamflow dynamics will change in response to future conditions is vital for the sustainable management of the fishery industry. In this paper, we focus on improving the accuracy of river discharge estimates on relatively small-scale sub-catchments (100 ~ 40,000 km2) in the headwaters of the Amazon River basin. The Hillslope River Routing (HRR) hydrologic model and remotely sensed datasets are used. We provide annual runoff, seasonal patterns, and daily discharge characteristics for 81 known migration reaches. The model is calibrated for the period 2000-2014 and climate forecasts for the period 2070-2100 are used to assess future changes in streamflow dynamics. The forecasts for the 2070 to 2100 period were obtained by selecting 5 climate models from IPCC's Fifth Assessment Report (AR5) Coupled Model Intercomparison Project Phase 5 (CMIP5) based on their ability to represent the main aspects of recent (1970 to 2000) Amazon climate. The river network for the HRR model is developing using surface topography based on the SRTM digital elevation model. Key model forcings include precipitation (TRMM 3B42) and evapotranspiration (MODIS ET, MOD16). Model parameters for soil depth, hydraulic conductivity, runoff coefficients and lateral routing were initially approximated based on literature values and adjusted during calibration. Measurements from stream gauges located near the reaches of interest were used for

  13. The atmospheric sulfur cycle over the Amazon Basin. II - Wet season

    Science.gov (United States)

    Andreae, M. O.; Bingemer, H.; Berresheim, H.; Jacob, D. J.; Lewis, B. L.

    1990-01-01

    The fluxes and concentrations of atmospheric sulfur species were determined at ground level and from aircraft over the Amazon Basin during the 1987 wet season, providing a comprehensive description of the sulfur cycle over a remote tropical region. The vertical profile of dimethylsulfide (DMS) during the wet season was found to be very similar to that measured during the dry season, suggesting little seasonal variation in DMS fluxes. The concentrations of H2S were almost an order of magnitude higher than those of DMS, which makes H2S the most important biogenic source species in the atmosheric sulfur cycle over the Amazon Basin. Using the gradient-flux approach, the flux of DMS at the top of the tree canopy was estimated. The canopy was a source of DMS during the day, and a weak sink during the night. Measurements of sulfur gas emissions from soils, using the chamber method, showed very small fluxes, consistent with the hypothesis that the forest canopy is the major source of sulfur gases. The observed soil and canopy emission fluxes are similar to those measured in temperate regions. The concentrations of SO2 and sulfate aerosol in the wet season atmosphere were similar to dry season values.

  14. Dependence of hydropower energy generation on forests in the Amazon Basin at local and regional scales.

    Science.gov (United States)

    Stickler, Claudia M; Coe, Michael T; Costa, Marcos H; Nepstad, Daniel C; McGrath, David G; Dias, Livia C P; Rodrigues, Hermann O; Soares-Filho, Britaldo S

    2013-06-04

    Tropical rainforest regions have large hydropower generation potential that figures prominently in many nations' energy growth strategies. Feasibility studies of hydropower plants typically ignore the effect of future deforestation or assume that deforestation will have a positive effect on river discharge and energy generation resulting from declines in evapotranspiration (ET) associated with forest conversion. Forest loss can also reduce river discharge, however, by inhibiting rainfall. We used land use, hydrological, and climate models to examine the local "direct" effects (through changes in ET within the watershed) and the potential regional "indirect" effects (through changes in rainfall) of deforestation on river discharge and energy generation potential for the Belo Monte energy complex, one of the world's largest hydropower plants that is currently under construction on the Xingu River in the eastern Amazon. In the absence of indirect effects of deforestation, simulated deforestation of 20% and 40% within the Xingu River basin increased discharge by 4-8% and 10-12%, with similar increases in energy generation. When indirect effects were considered, deforestation of the Amazon region inhibited rainfall within the Xingu Basin, counterbalancing declines in ET and decreasing discharge by 6-36%. Under business-as-usual projections of forest loss for 2050 (40%), simulated power generation declined to only 25% of maximum plant output and 60% of the industry's own projections. Like other energy sources, hydropower plants present large social and environmental costs. Their reliability as energy sources, however, must take into account their dependence on forests.

  15. A Behavioral Model of Landscape Change in the Amazon Basin: The Colonist Case

    Science.gov (United States)

    Walker, R. A.; Drzyzga, S. A.; Li, Y. L.; Wi, J. G.; Caldas, M.; Arima, E.; Vergara, D.

    2004-01-01

    This paper presents the prototype of a predictive model capable of describing both magnitudes of deforestation and its spatial articulation into patterns of forest fragmentation. In a departure from other landscape models, it establishes an explicit behavioral foundation for algorithm development, predicated on notions of the peasant economy and on household production theory. It takes a 'bottom-up' approach, generating the process of land-cover change occurring at lot level together with the geography of a transportation system to describe regional landscape change. In other words, it translates the decentralized decisions of individual households into a collective, spatial impact. In so doing, the model unites the richness of survey research on farm households with the analytical rigor of spatial analysis enabled by geographic information systems (GIs). The paper describes earlier efforts at spatial modeling, provides a critique of the so-called spatially explicit model, and elaborates a behavioral foundation by considering farm practices of colonists in the Amazon basin. It then uses, insight from the behavioral statement to motivate a GIs-based model architecture. The model is implemented for a long-standing colonization frontier in the eastern sector of the basin, along the Trans-Amazon Highway in the State of Para, Brazil. Results are subjected to both sensitivity analysis and error assessment, and suggestions are made about how the model could be improved.

  16. Beyond the model democracy: observational constraints indicate risk of drying in the Amazon basin

    Science.gov (United States)

    Shiogama, Hideo; Emori, Seita; Hanasaki, Naota; Abe, Manabu; Masutomi, Yuji; Takahashi, Kiyoshi; Nozawa, Toru

    2013-04-01

    Climate warming due to human activities will be accompanied by hydrological cycle changes. Economies, societies and ecosystems in South America (SA) are vulnerable to such water resource changes. Hence, water resource impact assessments for SA, and corresponding adaptation and mitigation policies, have attracted increased attention. However, substantial uncertainties remain in the current water resource assessments that are based on multiple coupled Atmosphere Ocean General Circulation models. This uncertainty varies from significant wetting to catastrophic drying. By applying a statistical method, we characterised the uncertainty and identified global-scale metrics for measuring the reliability of water resource assessments in SA. Here we show that, whereas the ensemble mean assessment suggested wetting across most of SA, the observational constraints indicate a higher probability of drying in the Amazon basin. Naive over-reliance on the consensus of models can lead to inappropriate decision making. Reference: Shiogama, H. et al. Observational constraints indicate risk of drying in the Amazon basin. Nature Communications 2:253 doi: 10.1038/ncomms1252 (2011).

  17. Palms and Palm Communities in the Upper Ucayali River Valley - a Little-Known Region in the Amazon Basin

    DEFF Research Database (Denmark)

    Balslev, Henrik; Eiserhardt, Wolf L.; Kristiansen, Thea

    2010-01-01

    – are cornerstone species for the survival of many animals, and palms contribute substantially to forest inventories in which they are often among the ten most important families. Still, the palms and palm communities of some parts of the Amazon basin remain poorly studied and little known. We travelled to a little...

  18. Tertiary tectonism in the Tapajos River Area, Amazon Basin; Tectonismo terciario na area do Rio Tapajos, Bacia do Amazonas

    Energy Technology Data Exchange (ETDEWEB)

    Travassos, W.A.S. [PETROBRAS, Belem, PA (Brazil). Distrito de Exploracao do Norte; Morais Barbosa Filho, C. de [PETROBRAS, Manaus, AM (Brazil). Distrito de Exploracao da Amazonia Ocidental

    1990-07-01

    Studies of a deformed sedimentary zone occurred during the tertiary period on the Amazon Basin, its localization on the region of the Tapajos River are discussed. The origin, characteristics and identification of these zone through seismic, gravimetric and aero-magnetometric surveys are also presented. 17 figs., 25 refs.

  19. Fluvial bar dynamics in large meandering rivers with different sediment supply in the Amazon River basin

    Science.gov (United States)

    Monegaglia, Federico; Zolezzi, Guido; Tubino, Marco; Henshaw, Alex

    2017-04-01

    Sediments in the large meandering rivers of the Amazon basin are known to be supplied by sources providing highly different magnitudes of sediment input and storage, ranging from the sediment-rich Andean region to the sediment-poor Central Trough. Recent observations have highlighted how such differences in sediment supply have an important, net effect on the rates of planform activity of meandering rivers in the basin, in terms of meander migration and frequency of cutoffs. In this work we quantify and discuss the effect of sediment supply on the organization of macroscale sediment bedforms on several large meandering rivers in the Amazon basin, and we link our findings with those regarding the rates of planform activity. Our analysis is conducted through the newly developed software PyRIS, which enables us to perform extensive multitemporal analysis of river morphodynamics from multispectral remotely sensed Landsat imagery in a fully automated fashion. We show that large rivers with low sediment supply tend to develop alternate bars that consistently migrate through long reaches, characterized at the same time by limited planform development. On the contrary, high sediment supply is associated with the development of point bars that are well-attached to the evolving meander bends and that follow temporal oscillations around the bend apexes, which in turn show rapid evlution towards complex meander shapes. Finally, rivers with intermediate rates of sediment supply develop rather steady point bars associated with slowly migrating, regular meanders. We finally discuss the results of the image analysis in the light of the properties of river planform metrics (like channel curvature and width) for the examined classes of river reaches with different sediment supply rates.

  20. Surface water quality and deforestation of the Purus river basin, Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Eduardo Antonio Ríos-Villamizar

    2016-12-01

    Full Text Available Abstract In the last years, deforestation constitutes a threat for the aquatic ecosystems. This paper aims to characterize the water quality of the Purus river in the Brazilian Amazon, and investigate the relations between water quality and deforestation of the Purus river basin over a 9-year period, as well as to quantify the Purus river basin’s land cover changes (% in a 5-year period. Sampling data from upstream to downstream show a decrease in pH-value, dissolved oxygen, electrical conductivity, and total suspended solids. Correlation analysis revealed a significant negative correlation of the accumulated total deforestation values (km2 with the pH-value (in all the study sites, and a significant positive correlation with temperature (only in two sites. However, the deforestation rates (km2/year did not present, in none of the study stations, any significant correlation with water quality parameters. It seems that the effects of deforestation on water quality are related not with the rate but with the total area deforested. It was estimated that the basin’s forested area decreased by 5.17%. Since similar attributes are common in other basins of the whitewater systems of the Brazilian Amazon, this results may be seen as a warning on the effects of deforestation on water quality (reduction in pH and increment in temperature values, in larger areas than those of our study sites. To maintain the conservation and preservation status of the Purus river basin, it is necessary, the implementation of a transboundary watershed management program that could serve as a conservation model for Brazil and other countries of the Amazonian region.

  1. Medicinal plants used in Rondônia, Western Amazon, Brazil

    Directory of Open Access Journals (Sweden)

    M.R.A. Santos

    2014-01-01

    Full Text Available This study refers to the use of medicinal plants by populations in the Western Amazon and provides information that can be used in phytochemical studies. It draws upon the traditional knowledge regarding the use of medicinal plants in five regions of the state of Rondônia, in the Brazilian Amazon, focusing on native species. The field research was carried out in five municipalities of the state of Rondônia: Ariquemes, Buritis, Candeias do Jamari, Cujubim and Itapoa do Oeste, characterized by primary economic sectors: agriculture, cattle farming, plant extraction and mineral exploration. Structured interviews were applied to 227 persons chosen because of their prestige in the communities in relation to the knowledge and use of medicinal plants, identifying the therapeutic purpose, parts of the plant used and methods of preparation. The species were taxonomically identified. The ethnobotanic knowledge (inferred by the number of uses of medicinal plants per person was correlated with the Brazilian region of origin, age, and gender of the interviewees. According to the collected data, 34 botanical families and 53 native species were identified. Of the 53 species, only 7 occur exclusively in the Amazon Forest: Theobroma grandiflorum (Willd. ex Spreng. K. Schum., Psidium densicomum Mart. ex DC, Piper cavalcantei Yunck., Pilocarpus microphyllus Stapf ex Wardlew., Euterpe oleracea Mart., Croton cajucara Benth., Baccharis altimontana G. Heiden. The most common disorders treated with the plants were kidney problems, influenza, generalized infections and inflammations, malaria and high blood pressure. Leaves were the most used parts in preparations. Barks, fruits, roots, flowers, stems, seeds, oils, buds, tubercles, and rhizomes were also mentioned. Thirteen forms of preparations were recorded, and infusion and decoction were the most used. Syrups, juices, flour, sap, oil and parts of the plant blended with milk, honey and coffee or flamed, macerated and

  2. Simulation of Water Sources and Precipitation Recycling for the MacKenzie, Mississippi and Amazon River Basins

    Science.gov (United States)

    Bosilovich, Michael G.; Chern, Jiun-Dar

    2005-01-01

    An atmospheric general circulation model simulation for 1948-1997 of the water budgets for the MacKenzie, Mississippi and Amazon River basins is presented. In addition to the water budget, we include passive tracers to identify the geographic sources of water for the basins, and the analysis focuses on the mechanisms contributing to precipitation recycling in each basin. While each basin s precipitation recycling has a strong dependency on evaporation during the mean annual cycle, the interannual variability of the recycling shows important relationships with the atmospheric circulation. The MacKenzie River basin has only a weak interannual dependency on evaporation, where the variations in zonal moisture transport from the Pacific Ocean can affect the basin water cycle. On the other hand, the Mississippi River basin has strong interannual dependencies on evaporation. While the precipitation recycling weakens with increased low level jet intensity, the evaporation variations exert stronger influence in providing water vapor for convective precipitation at the convective cloud base. High precipitation recycling is also found to be partly connected to warm SSTs in the tropical Pacific Ocean. The Amazon River basin evaporation exhibits small interannual variations, so that the interannual variations of precipitation recycling are related to atmospheric moisture transport from the tropical south Atlantic Ocean. Increasing SSTs over the 50-year period are causing increased easterly transport across the basin. As moisture transport increases, the Amazon precipitation recycling decreases (without real time varying vegetation changes). In addition, precipitation recycling from a bulk diagnostic method is compared to the passive tracer method used in the analysis. While the mean values are different, the interannual variations are comparable between each method. The methods also exhibit similar relationships to the terms of the basin scale water budgets.

  3. Ichnologic evidence of a Cambrian age in the southern Amazon Craton: Implications for the onset of the Western Gondwana history

    Science.gov (United States)

    Santos, Hudson P.; Mángano, M. Gabriela; Soares, Joelson L.; Nogueira, Afonso C. R.; Bandeira, José; Rudnitzki, Isaac D.

    2017-07-01

    Colonization of the infaunal ecospace by burrowing bilaterians is one of the most important behavioral innovations during the Ediacaran-Cambrian transition. The establishment of vertical burrows by suspension feeders in high-energy nearshore settings during Cambrian Age 2 is reflected by the appearance of the Skolithos Ichnofacies. For the first time, unquestionable vertical burrows typical of the Skolithos Ichnofacies, such as Skolithos linearis, Diplocraterion parallelum and Arenicolites isp., are recorded from nearshore siliciclastic deposits of the Raizama Formation, southeastern Amazon Craton, Brazil. Integration of ichnologic and sedimentologic datasets suggests that these trace fossils record colonization of high-energy and well-oxygenated nearshore sandy environments. Chronostratigraphically, the presence of these vertical burrows indicates an age not older than early Cambrian for the Raizama Formation, which traditionally has been regarded as Ediacaran. Therefore, the Raizama ichnofauna illustrates the advent of modern Phanerozoic ecology marked by the Agronomic Revolution. The discovery of the Skolithos Ichnofacies in these shallow-marine strata suggests possible connections between some central Western Gondwana basins.

  4. Incidence of childhood leukemia and oil exploitation in the Amazon basin of Ecuador.

    Science.gov (United States)

    Hurtig, Anna-Karin; San Sebastián, Miguel

    2004-01-01

    To determine whether there was any difference in childhood leukemia incidence rates between populations living in the proximity to oil fields and those living in areas free from oil exploitation in the Amazon basin of Ecuador, 91 cancer cases among children (0-14 years) from the provinces of Sucumbios, Orellana, Napo, and Pastaza during the period 1985-2000 were studied. The relative risks for all leukemias indicated significantly elevated levels in the youngest age group (0-4 years), both genders combined (RR 3.48, 95% CI 1.25-9.67), and in all age groups (0-14 years) combined for females (RR 2.60, 95% CI 1.11-6.08) and both genders combined (RR 2.56, 95% CI 1.35-4.86). There was no significant difference between the two groups in all other cancer sites combined. Study results are compatible with a relationship between childhood leukemia incidence and living in the proximity of oil fields in the Ecuadorian Amazon.

  5. Outbreak of Cutaneous Leishmaniasis in Peruvian Military Personnel Undertaking Training Activities in the Amazon Basin, 2010

    Science.gov (United States)

    Oré, Marianela; Sáenz, Eliana; Cabrera, Rufino; Sanchez, Juan F.; De Los Santos, Maxy B.; Lucas, Carmen M.; Núñez, Jorge H.; Edgel, Kimberly A.; Sopan, Justino; Fernández, Jorge; Carnero, Andres M.; Baldeviano, G. Christian; Arrasco, Juan C.; Graf, Paul C. F.; Lescano, Andres G.

    2015-01-01

    Military personnel deployed to the Amazon Basin are at high risk for cutaneous leishmaniasis (CL). We responded to an outbreak among Peruvian Army personnel returning from short-term training in the Amazon, conducting active case detection, lesion sample collection, and risk factor assessment. The attack rate was 25% (76/303); the incubation period was 2–36 weeks (median = 8). Most cases had one lesion (66%), primarily ulcerative (49%), and in the legs (57%). Real-time polymerase chain reaction (PCR) identified Leishmania (Viannia) braziliensis (59/61 = 97%) and L. (V.) guyanensis (2/61 = 3%). Being male (risk ratio [RR] = 4.01; P = 0.034), not wearing long-sleeve clothes (RR = 1.71; P = 0.005), and sleeping in open rooms (RR = 1.80; P = 0.009) were associated with CL. Sodium stibogluconate therapy had a 41% cure rate, less than previously reported in Peru (∼ 70%; P < 0.001). After emphasizing pre-deployment education and other basic prevention measures, trainees in the following year had lower incidence (1/278 = 0.4%; P < 0.001). Basic prevention can reduce CL risk in deployed militaries. PMID:26078320

  6. Epidemiology of viruses causing chronic hepatitis among populations from the Amazon Basin and related ecosystems

    Directory of Open Access Journals (Sweden)

    Echevarría José M.

    2003-01-01

    Full Text Available On the last twenty years, viral hepatitis has emerged as a serious problem in almost all the Amerindian communities studied in the Amazon Basin and in other Amazon-related ecological systems from the North and Center of South America. Studies performed on communities from Bolivia, Brazil, Colombia, Peru and Venezuela have shown a high endemicity of the hepatitis B virus (HBV infection all over the region, which is frequently associated to a high prevalence of infection by hepatitis D virus among the chronic HBV carriers. Circulation of both agents responds mainly to horizontal virus transmission during childhood through mechanisms that are not fully understood. By contrast, infection by hepatitis C virus (HCV, which is present in all the urban areas of South America, is still very uncommon among them. At the moment, there is not data enough to evaluate properly the true incidence that such endemicity may have on the health of the populations affected. Since viral transmission might be operated by mechanisms that could not be acting in other areas of the World, it seems essential to investigate such mechanisms and to prevent the introduction of HCV into these populations, which consequences for health could be very serious.

  7. RESERVES IN WESTERN BASINS PART IV: WIND RIVER BASIN

    Energy Technology Data Exchange (ETDEWEB)

    Robert Caldwell

    1998-04-01

    Vast quantities of natural gas are entrapped within various tight formations in the Rocky Mountain area. This report seeks to quantify what proportion of that resource can be considered recoverable under today's technological and economic conditions and discusses factors controlling recovery. The ultimate goal of this project is to encourage development of tight gas reserves by industry through reducing the technical and economic risks of locating, drilling and completing commercial tight gas wells. This report is the fourth in a series and focuses on the Wind River Basin located in west central Wyoming. The first three reports presented analyses of the tight gas reserves and resources in the Greater Green River Basin (Scotia, 1993), Piceance Basin (Scotia, 1995) and the Uinta Basin (Scotia, 1995). Since each report is a stand-alone document, duplication of language will exist where common aspects are discussed. This study, and the previous three, describe basin-centered gas deposits (Masters, 1979) which contain vast quantities of natural gas entrapped in low permeability (tight), overpressured sandstones occupying a central basin location. Such deposits are generally continuous and are not conventionally trapped by a structural or stratigraphic seal. Rather, the tight character of the reservoirs prevents rapid migration of the gas, and where rates of gas generation exceed rates of escape, an overpressured basin-centered gas deposit results (Spencer, 1987). Since the temperature is a primary controlling factor for the onset and rate of gas generation, these deposits exist in the deeper, central parts of a basin where temperatures generally exceed 200 F and drill depths exceed 8,000 feet. The abbreviation OPT (overpressured tight) is used when referring to sandstone reservoirs that comprise the basin-centered gas deposit. Because the gas resources trapped in this setting are so large, they represent an important source of future gas supply, prompting studies

  8. Symbiotic nitrogen-fixing bacterial populations trapped from soils under agroforestry systems in the Western Amazon

    Directory of Open Access Journals (Sweden)

    Paula Marcela Duque Jaramillo

    2013-12-01

    Full Text Available Cowpea (Vigna unguiculata is an important grain-producing legume that can forego nitrogen fertilization by establishing an efficient symbiosis with nitrogen-fixing bacteria. Although inoculating strains have already been selected for this species, little is known about the genotypic and symbiotic diversity of native rhizobia. Recently, Bradyrhizobium has been shown to be the genus most frequently trapped by cowpea in agricultural soils of the Amazon region. We investigated the genetic and symbiotic diversity of 148 bacterial strains with different phenotypic and cultural properties isolated from the nodules of the trap species cowpea, which was inoculated with samples from soils under agroforestry systems from the western Amazon. Sixty non-nodulating strains indicated a high frequency of endophytic strains in the nodules. The 88 authenticated strains had varying symbiotic efficiency. The SPAD (Soil Plant Analysis Development index (indirect measurement of chlorophyll content was more efficient at evaluating the contribution of symbiotic N2-fixation than shoot dry matter under axenic conditions. Cowpea-nodulating bacteria exhibited a high level of genetic diversity, with 68 genotypes identified by BOX-PCR. Sequencing of the 16S rRNA gene showed a predominance of the genus Bradyrhizobium, which accounted for 70 % of all strains sequenced. Other genera identified were Rhizobium, Ochrobactrum, Paenibacillus, Bosea, Bacillus, Enterobacter, and Stenotrophomonas. These results support the promiscuity of cowpea and demonstrate the high genetic and symbiotic diversity of rhizobia in soils under agroforestry systems, with some strains exhibiting potential for use as inoculants. The predominance of Bradyrhizobium in land uses with different plant communities and soil characteristics reflects the adaptation of this genus to the Amazon region.

  9. Mercury in the Tapajós River basin, Brazilian Amazon: a review.

    Science.gov (United States)

    Berzas Nevado, J J; Rodríguez Martín-Doimeadios, R C; Guzmán Bernardo, F J; Jiménez Moreno, M; Herculano, A M; do Nascimento, J L M; Crespo-López, M E

    2010-08-01

    This paper presents a review about mercury contamination and human exposure in the Tapajós River basin (Brazil), one of the major tributaries of the Amazon impacted by traditional gold mining from the mid 1980s. The most recent review in this region was published more than ten years ago and since then many articles about environment and especially human populations have revealed new aspects of mercury toxicology. Additionally, new biomarkers of mercury exposure and toxicity have been studied in these populations. However, there are still many open, about both mercury's biogeochemical cycle and mercury health risks. Further environmental and human risk research directions are proposed. Copyright 2010 Elsevier Ltd. All rights reserved.

  10. Nonlinear interactions between the Amazon River basin and the Tropical North Atlantic at interannual timescales

    Science.gov (United States)

    Builes-Jaramillo, Alejandro; Marwan, Norbert; Poveda, Germán; Kurths, Jürgen

    2017-07-01

    We study the physical processes involved in the potential influence of Amazon (AM) hydroclimatology over the Tropical North Atlantic (TNA) Sea Surface Temperatures (SST) at interannual timescales, by analyzing time series of the precipitation index (P-E) over AM, as well as the surface atmospheric pressure gradient between both regions, and TNA SSTs. We use a recurrence joint probability based analysis that accounts for the lagged nonlinear dependency between time series, which also allows quantifying the statistical significance, based on a twin surrogates technique of the recurrence analysis. By means of such nonlinear dependence analysis we find that at interannual timescales AM hydrology influences future states of the TNA SSTs from 0 to 2 months later with a 90-95% statistical confidence. It also unveils the existence of two-way feedback mechanisms between the variables involved in the processes: (1) precipitation over AM leads the atmospheric pressure gradient between TNA and AM from 0 to 2 month lags, (2) the pressure gradient leads the trade zonal winds over the TNA from 0 to 3 months and from 7 to 12 months, (3) the zonal winds lead the SSTs from 0 to 3 months, and (4) the SSTs lead precipitation over AM by 1 month lag. The analyses were made for time series spanning from 1979 to 2008, and for extreme precipitation events in the AM during the years 1999, 2005, 2009 and 2010. We also evaluated the monthly mean conditions of the relevant variables during the extreme AM droughts of 1963, 1980, 1983, 1997, 1998, 2005, and 2010, and also during the floods of 1989, 1999, and 2009. Our results confirm that the Amazon River basin acts as a land surface-atmosphere bridge that links the Tropical Pacific and TNA SSTs at interannual timescales. The identified mutual interactions between TNA and AM are of paramount importance for a deeper understanding of AM hydroclimatology but also of a suite of oceanic and atmospheric phenomena over the TNA, including recently

  11. Palm harvest impact in the western Amazon, Andes and Pacific lowlands

    DEFF Research Database (Denmark)

    Balslev, Henrik

    2011-01-01

    Palms are the most useful group of plants in tropical American forests and in this project we study the effect of extraction and trade of palms on forests in the western Amazon, Andes, and Pacific lowlands. We determine the size of the resource by making palm community studies in the different...... of ecosystems and use this to propose sustainable policies to the governments. The results are disseminated in a variety of ways, depending on need and stake holders, from popular leaflets and videos for farmers, reports for policy makers to scientific publications for the research community. The team behind...... forest formations and determine the number of species and individuals of all palm species. The genetic structure of useful palm species is studied to determine how much harvesting of the species contributes to genetic erosion of their populations, and whether extraction can be made without harm. We...

  12. Two soil hydrology formulations of ORCHIDEE (version Trunk.rev1311) tested for the Amazon basin

    Science.gov (United States)

    Guimberteau, M.; Ciais, P.; Ducharne, A.; Boisier, J. P.; Peng, S.; De Weirdt, M.; Verbeeck, H.

    2014-01-01

    -based dataset. The dry-season length between 4 and 7 months over the entire Amazon basin was found to be critical in distinguishing differences in hydrological feedbacks between the soil and the vegetation cover simulated by the two soil models. Overall, the 11 layer soil diffusion scheme provided little improvement in simulated hydrology on average over the wet tropical Amazonian sub-basins but a more significant improvement over the drier sub-basins. However, the use of the 11 layer soil diffusion scheme might become critical for assessments of future hydrological changes, especially in southern regions of the Amazon basin where longer dry season and more severe droughts are expected in the next century.

  13. Land-use systems affect Archaeal community structure and functional diversity in western Amazon soils

    Directory of Open Access Journals (Sweden)

    Acácio Aparecido Navarrete

    2011-10-01

    Full Text Available The study of the ecology of soil microbial communities at relevant spatial scales is primordial in the wide Amazon region due to the current land use changes. In this study, the diversity of the Archaea domain (community structure and ammonia-oxidizing Archaea (richness and community composition were investigated using molecular biology-based techniques in different land-use systems in western Amazonia, Brazil. Soil samples were collected in two periods with high precipitation (March 2008 and January 2009 from Inceptisols under primary tropical rainforest, secondary forest (5-20 year old, agricultural systems of indigenous people and cattle pasture. Denaturing gradient gel electrophoresis of polymerase chain reaction-amplified DNA (PCR-DGGE using the 16S rRNA gene as a biomarker showed that archaeal community structures in crops and pasture soils are different from those in primary forest soil, which is more similar to the community structure in secondary forest soil. Sequence analysis of excised DGGE bands indicated the presence of crenarchaeal and euryarchaeal organisms. Based on clone library analysis of the gene coding the subunit of the enzyme ammonia monooxygenase (amoA of Archaea (306 sequences, the Shannon-Wiener function and Simpson's index showed a greater ammonia-oxidizing archaeal diversity in primary forest soils (H' = 2.1486; D = 0.1366, followed by a lower diversity in soils under pasture (H' = 1.9629; D = 0.1715, crops (H' = 1.4613; D = 0.3309 and secondary forest (H' = 0.8633; D = 0.5405. All cloned inserts were similar to the Crenarchaeota amoA gene clones (identity > 95 % previously found in soils and sediments and distributed primarily in three major phylogenetic clusters. The findings indicate that agricultural systems of indigenous people and cattle pasture affect the archaeal community structure and diversity of ammonia-oxidizing Archaea in western Amazon soils.

  14. Reserves in western basins: Part 1, Greater Green River basin

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-01

    This study characterizes an extremely large gas resource located in low permeability, overpressured sandstone reservoirs located below 8,000 feet drill depth in the Greater Green River basin, Wyoming. Total in place resource is estimated at 1,968 Tcf. Via application of geologic, engineering and economic criteria, the portion of this resource potentially recoverable as reserves is estimated. Those volumes estimated include probable, possible and potential categories and total 33 Tcf as a mean estimate of recoverable gas for all plays considered in the basin. Five plays (formations) were included in this study and each was separately analyzed in terms of its overpressured, tight gas resource, established productive characteristics and future reserves potential based on a constant $2/Mcf wellhead gas price scenario. A scheme has been developed to break the overall resource estimate down into components that can be considered as differing technical and economic challenges that must be overcome in order to exploit such resources: in other words, to convert those resources to economically recoverable reserves. Total recoverable reserves estimates of 33 Tcf do not include the existing production from overpressured tight reservoirs in the basin. These have estimated ultimate recovery of approximately 1.6 Tcf, or a per well average recovery of 2.3 Bcf. Due to the fact that considerable pay thicknesses can be present, wells can be economic despite limited drainage areas. It is typical for significant bypassed gas to be present at inter-well locations because drainage areas are commonly less than regulatory well spacing requirements.

  15. Provenance of sandstone on the western flank of Anambra Basin ...

    African Journals Online (AJOL)

    The localities are in the western flank of the Anambra basin, southwestern Nigeria. Petrographic study shows that the sandstone deposits are composed of variable amounts of quartz, feldspars and lithic fragments with minor occurrence of authigenic silica and chlorite cements. Quartz is the predominant detrital mineral in all ...

  16. Genetic diversity of vaccine candidate antigens in Plasmodium falciparum isolates from the Amazon basin of Peru

    Directory of Open Access Journals (Sweden)

    Lucas Carmen M

    2008-05-01

    Full Text Available Abstract Background Several of the intended Plasmodium falciparum vaccine candidate antigens are highly polymorphic and could render a vaccine ineffective if their antigenic sites were not represented in the vaccine. In this study, characterization of genetic variability was performed in major B and T-cell epitopes within vaccine candidate antigens in isolates of P. falciparum from Peru. Methods DNA sequencing analysis was completed on 139 isolates of P. falciparum collected from endemic areas of the Amazon basin in Loreto, Peru from years 1998 to 2006. Genetic diversity was determined in immunological important regions in circumsporozoite protein (CSP, merozoite surface protein-1 (MSP-1, apical membrane antigen-1 (AMA-1, liver stage antigen-1 (LSA-1 and thrombospondin-related anonymous protein (TRAP. Alleles identified by DNA sequencing were aligned with the vaccine strain 3D7 and DNA polymorphism analysis and FST study-year pairwise comparisons were done using the DnaSP software. Multilocus analysis (MLA was performed and average of expected heterozygosity was calculated for each loci and haplotype over time. Results Three different alleles for CSP, seven for MSP-1 Block 2, one for MSP-1 Block 17, three for AMA-1 and for LSA-1 each and one for TRAP were identified. There were 24 different haplotypes in 125 infections with complete locus typing for each gene. Conclusion Characterization of the genetic diversity in Plasmodium isolates from the Amazon Region of Peru showed that P. falciparum T and B cell epitopes in these antigens have polymorphisms more similar to India than to Africa. These findings are helpful in the formulation of a vaccine considering restricted repertoire populations.

  17. Evaluation of drought indices at interannual to climate change timescales: a case study over the Amazon and Mississippi river basins

    OpenAIRE

    E. Joetzjer; H. Douville; C. Delire; P. Ciais; B. Decharme; S. Tyteca

    2012-01-01

    The present study compares three meteorological drought indices (scPDSI, SPI and SPEI respectively) and their ability to account for the variations of annual mean river discharge on both interannual and climate change timescales. The Standardized Runoff Index (SRI) is used as a proxy of river discharge. The Mississippi and Amazon river basins provide two contrasted testbeds for this analysis. All meteorological drought indices are derived from monthly 2-meter temperature and/or precipitation,...

  18. Placentation in dolphins from the Amazon River Basin: the Boto, Inia geoffrensis, and the Tucuxi, Sotalia fluviatilis

    OpenAIRE

    da Silva, Vera M; Carter, Anthony M; Ambrosio, Carlos E; Carvalho, Ana F; Bonatelli, Marina; Lima, Marcelo C; Miglino, Angelica M

    2007-01-01

    Abstract A recent reassessment of the phylogenetic affinities of cetaceans makes it timely to compare their placentation with that of the artiodactyls. We studied the placentae of two sympatric species of dolphin from the Amazon River Basin, representing two distinct families. The umbilical cord branched to supply a bilobed allantoic sac. Small blood vessels and smooth muscle bundles were found within the stroma of the cord. Foci of squamous metaplasia occurred in the allanto-amnion and allan...

  19. Western Gas Sands Project. Quarterly basin activities report

    Energy Technology Data Exchange (ETDEWEB)

    1978-07-31

    A summation is presented of the drilling and testing activity in the four primary study areas and the USGS designated core sites of the Western Gas Sands Project (WGSP). Pertinent review information for April, May and June 1978, included for each study area, is divided into two sections. The core program section identifies industry activity within the USGS recommended core areas and relates the status of WGSP core acquisition developments. The second part, the activity section, details drilling and testing operations of interest to the WGSP throughout the entire basin or province. Newly staked or completed wells are listed in tabular form and shown on a map. Information is included on activities in the Northern Great Plains Province, the greater Green River Basin, the Uinta Basin, and the Piceance Basin.

  20. Comparative cytogenetics of some marsupial species (Didelphimorphia, Didelphidae from the Amazon basin

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Faresin e Silva

    2017-10-01

    Full Text Available We investigated the karyotype of 18 didelphid species captured at 13 localities in the Brazilian Amazon, after conventional staining, C-banding, Ag-NOR and fluorescent in situ hybridization (FISH using the 18S rDNA probe. Variations were found in the X chromosome, heterochromatin distribution and the 18S rDNA sequence. The main variation observed was in the position of the centromere in the X chromosome of Caluromys philander Linnaeus, 1758 and Marmosa murina Linnaeus, 1758. For both species, the X chromosome showed a geographical segregation in the pattern of variation between eastern and western Brazil, with a possible contact area in the central Amazon. C-banding on the X chromosome revealed two patterns for the species of Marmosops Matschie, 1916, apparently without geographic or specific relationships. The nucleolus organizer region (NOR of all species was confirmed with the 18S rDNA probe, except on the Y chromosome of Monodelphis touan Shaw, 1800. The distribution of this marker varied only in the genus Marmosa Gray, 1821 [M. murina Thomas, 1905 and M. demerarae Thomas, 1905]. Considering that simple NORs are seen as a plesiomorphic character, we conclude that the species Marmosa spp. and Didelphis marsupialis Linnaeus, 1758 evolved independently to the multiple condition. By increasing the sample, using chromosomal banding, and FISH, we verified that marsupials present intra- and interspecific chromosomal variations, which suggests the occurrence of frequent chromosomal rearrangements in the evolution of this group. This observation contrasts with the chromosomal conservatism expected for didelphids.

  1. DNA barcodes of Rosy Tetras and allied species (Characiformes: Characidae: Hyphessobrycon) from the Brazilian Amazon basin.

    Science.gov (United States)

    Castro Paz, Francis Paola; Batista, Jacqueline da Silva; Porto, Jorge Ivan Rebelo

    2014-01-01

    DNA barcoding can be an effective tool for fast and accurate species-level identification based on sequencing of the mitochondrial cytochrome c oxidase subunit (COI) gene. The diversity of this fragment can be used to estimate the richness of the respective species. In this study, we explored the use of DNA barcoding in a group of ornamental freshwater fish of the genus Hyphessobrycon. We sequenced the COI from 10 species of Hyphessobrycon belonging to the "Rosy Tetra Clade" collected from the Amazon and Negro River basins and combined our results with published data. The average conspecific and congeneric Kimura 2-parameter distances were 2.3% and 19.3%, respectively. Six of the 10 species were easily distinguishable by DNA barcoding (H. bentosi, H. copelandi, H. eques, H. epicharis, H. pulchrippinis, and H. sweglesi), whereas the remaining species (H. erythrostigma, H. pyrrhonotus, H. rosaceus and H. socolofi) lacked reciprocal monophyly. Although the COI gene was not fully diagnostic, the discovery of distinct evolutionary units in certain Hyphessobrycon species under the same specific epithet as well as haplotype sharing between different species suggest that DNA barcoding is useful for species identification in this speciose genus.

  2. DNA barcodes of Rosy Tetras and allied species (Characiformes: Characidae: Hyphessobrycon from the Brazilian Amazon basin.

    Directory of Open Access Journals (Sweden)

    Francis Paola Castro Paz

    Full Text Available DNA barcoding can be an effective tool for fast and accurate species-level identification based on sequencing of the mitochondrial cytochrome c oxidase subunit (COI gene. The diversity of this fragment can be used to estimate the richness of the respective species. In this study, we explored the use of DNA barcoding in a group of ornamental freshwater fish of the genus Hyphessobrycon. We sequenced the COI from 10 species of Hyphessobrycon belonging to the "Rosy Tetra Clade" collected from the Amazon and Negro River basins and combined our results with published data. The average conspecific and congeneric Kimura 2-parameter distances were 2.3% and 19.3%, respectively. Six of the 10 species were easily distinguishable by DNA barcoding (H. bentosi, H. copelandi, H. eques, H. epicharis, H. pulchrippinis, and H. sweglesi, whereas the remaining species (H. erythrostigma, H. pyrrhonotus, H. rosaceus and H. socolofi lacked reciprocal monophyly. Although the COI gene was not fully diagnostic, the discovery of distinct evolutionary units in certain Hyphessobrycon species under the same specific epithet as well as haplotype sharing between different species suggest that DNA barcoding is useful for species identification in this speciose genus.

  3. Exposures and cancer incidence near oil fields in the Amazon basin of Ecuador.

    Science.gov (United States)

    San Sebastián, M; Armstrong, B; Córdoba, J A; Stephens, C

    2001-08-01

    To examine environmental exposure and incidence and mortality of cancer in the village of San Carlos surrounded by oil fields in the Amazon basin of Ecuador. Water samples of the local streams were analyzed for total petroleum hydrocarbons (TPHs). A preliminary list of potential cancer cases from 1989 to 1998 was prepared. Cases were compared with expected numbers of cancer morbidity and mortality registrations from a Quito reference population. Water analysis showed severe exposure to TPHs by the residents. Ten patients with cancer were diagnosed while resident in the village of San Carlos. An overall excess for all types of cancer was found in the male population (8 observed v 3.5 expected) with a risk 2.26 times higher than expected (95% confidence interval (95% CI) 0.97 to 4.46). There was an overall excess of deaths for all types of cancer (6 v 1.6 expected) among the male population 3.6 times higher than the reference population (95% CI 1.31 to 7.81). The observed excess of cancer might be associated with the pollution of the environment by toxic contaminants coming from the oil production.

  4. Bioaccumulation of methylmercury in fish tissue from the Roosevelt River, Southwestern Amazon basin

    Directory of Open Access Journals (Sweden)

    Marcelo Rodrigues dos Anjos

    2016-06-01

    Full Text Available Mercury is a major pollutant in the Amazon River system, and its levels in fish and human hair are usually above the limit recommended by health agencies. The objective of this study was to analyze the methylmercury (MeHg concentration in fish tissue from the Roosevelt River. The river's water velocity, depth, pH, temperature, electrical conductivity, dissolved oxygen and substrate type were measured, and fifty specimens distributed in 14 fish species were collected. A total of 64.3% of the sampled species were of the order Characiform and 71.4% of the species were carnivores. Fifty percent of the species had MeHg concentrations above threshold limit (Hg-T 0.5 mg kg-1 established for food by the World Health Organization. Cichla monoculus had the highest value of MeHg (2.45 mg kg-1. The MeHg concentration in fish varied according to dietary habits. The study also found bioaccumulation of MeHg in fish tissue in the following descending order: carnivorous > detritivorous > frugivore. Low significant correlations were found between fish weight or length and MeHg. Further studies on MeHg contamination are recommended in tissues of fish consumed in human riverine communities in the Roosevelt River Basin.

  5. Trends in entropy production during ecosystem development in the Amazon Basin

    Science.gov (United States)

    Holdaway, Robert J.; Sparrow, Ashley D.; Coomes, David A.

    2010-01-01

    Understanding successional trends in energy and matter exchange across the ecosystem–atmosphere boundary layer is an essential focus in ecological research; however, a general theory describing the observed pattern remains elusive. This paper examines whether the principle of maximum entropy production could provide the solution. A general framework is developed for calculating entropy production using data from terrestrial eddy covariance and micrometeorological studies. We apply this framework to data from eight tropical forest and pasture flux sites in the Amazon Basin and show that forest sites had consistently higher entropy production rates than pasture sites (0.461 versus 0.422 W m−2 K−1, respectively). It is suggested that during development, changes in canopy structure minimize surface albedo, and development of deeper root systems optimizes access to soil water and thus potential transpiration, resulting in lower surface temperatures and increased entropy production. We discuss our results in the context of a theoretical model of entropy production versus ecosystem developmental stage. We conclude that, although further work is required, entropy production could potentially provide a much-needed theoretical basis for understanding the effects of deforestation and land-use change on the land-surface energy balance. PMID:20368262

  6. Basin-wide variations in Amazon forest structure and function are mediated by both soils and climate

    Science.gov (United States)

    Quesada, C. A.; Phillips, O. L.; Schwarz, M.; Czimczik, C. I.; Baker, T. R.; Patiño, S.; Fyllas, N. M.; Hodnett, M. G.; Herrera, R.; Almeida, S.; Alvarez Dávila, E.; Arneth, A.; Arroyo, L.; Chao, K. J.; Dezzeo, N.; Erwin, T.; di Fiore, A.; Higuchi, N.; Honorio Coronado, E.; Jimenez, E. M.; Killeen, T.; Lezama, A. T.; Lloyd, G.; López-González, G.; Luizão, F. J.; Malhi, Y.; Monteagudo, A.; Neill, D. A.; Núñez Vargas, P.; Paiva, R.; Peacock, J.; Peñuela, M. C.; Peña Cruz, A.; Pitman, N.; Priante Filho, N.; Prieto, A.; Ramírez, H.; Rudas, A.; Salomão, R.; Santos, A. J. B.; Schmerler, J.; Silva, N.; Silveira, M.; Vásquez, R.; Vieira, I.; Terborgh, J.; Lloyd, J.

    2012-06-01

    Forest structure and dynamics vary across the Amazon Basin in an east-west gradient coincident with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. Soil samples were collected in a total of 59 different forest plots across the Amazon Basin and analysed for exchangeable cations, carbon, nitrogen and pH, with several phosphorus fractions of likely different plant availability also quantified. Physical properties were additionally examined and an index of soil physical quality developed. Bivariate relationships of soil and climatic properties with above-ground wood productivity, stand-level tree turnover rates, above-ground wood biomass and wood density were first examined with multivariate regression models then applied. Both forms of analysis were undertaken with and without considerations regarding the underlying spatial structure of the dataset. Despite the presence of autocorrelated spatial structures complicating many analyses, forest structure and dynamics were found to be strongly and quantitatively related to edaphic as well as climatic conditions. Basin-wide differences in stand-level turnover rates are mostly influenced by soil physical properties with variations in rates of coarse wood production mostly related to soil phosphorus status. Total soil P was a better predictor of wood production rates than any of the fractionated organic- or inorganic-P pools. This suggests that it is not only the immediately available P forms, but probably the entire soil phosphorus pool that is interacting with forest growth on longer timescales. A role for soil potassium in modulating Amazon forest dynamics through its effects on stand-level wood density was also detected. Taking this into account, otherwise enigmatic variations in stand-level biomass across the Basin were then accounted for through the

  7. Can Transport of Saharan Dust Explain Extensive Clay Deposits in the Amazon Basin? A Test Using Radiogenic Isotopes

    Science.gov (United States)

    Andreae, M. O.; Abouchami, W.; Näthe, K.; Kumar, A.; Galer, S. J.; Jochum, K. P.; Williams, E.; Horbe, A. M.; Rosa, J. W.; Adams, D. K.; Balsam, W. R.

    2012-12-01

    The Bodélé Depression, located in the Southern Sahara, is a huge source of atmospheric dust and thus an important element in biogeochemical cycles and the radiative budget of Earth's atmosphere. Previous studies have shown that Saharan dust transport across the Atlantic acts as an important source of mineral nutrients to the Amazon rainforest. The Belterra Clay, which outcrops extensively across the Amazon Basin in Brazil, has been proposed to result from dry deposition of African dusts. We have investigated this hypothesis by measuring the radiogenic isotopic composition (Sr, Nd and Pb) of a suite of samples from the Belterra Clay, the Bodélé Depression, dusts deposits collected at various locations along the airmass transport trajectory, as well as loess from the Cape Verde Islands. Radiogenic isotope systems are powerful tracers of provenance and can be used to fingerprint dust sources and atmospheric transport patterns. Our results identify distinct isotopic signatures in the Belterra Clay samples and the African sources. The Belterra Clay display radiogenic Sr and Pb isotope ratios associated with non-radiogenic Nd isotope signatures. In contrast, Bodélé samples and dusts deposits show lower Pb isotope ratios, variable 87Sr/86Sr, and relatively homogeneous Nd isotopic compositions, albeit more radiogenic than those of the Belterra Clay. Our data show unambiguously that the Belterra Clay is not derived from African dust deposition, nor from the Andean chain, as originally suggested by W. Sombroek. Rather, isotopic compositions and Nd model ages are consistent with simple mixing of Archean and younger Proterozoic terranes within the Amazon Basin as a result of weathering and erosion under humid tropical conditions. Whether Saharan dusts contribute to the fertilization in the Amazon Basin cannot be ruled out, however, since the African dust isotopic signature is expected to be entirely overprinted by local sources. Radiogenic isotope data obtained on

  8. Surface Freshwater Storage and Variability in the Amazon Basin from Multi-Satellite Observations, 1993-2007

    Science.gov (United States)

    Papa, Fabrice; Frappart, Frederic; Guntner, Andreas; Prigent, Catherine; Aires, Filipe; Getirana, Augusto; Maurer, Raffael

    2013-01-01

    The amount of water stored and moving through the surface water bodies of large river basins (river, floodplains, wetlands) plays a major role in the global water and biochemical cycles and is a critical parameter for water resources management. However, the spatio-temporal variations of these freshwater reservoirs are still widely unknown at the global scale. Here, we propose a hypsographic curve approach to estimate surface freshwater storage variations over the Amazon basin combining surface water extent from a multi-satellite-technique with topographic data from the Global Digital Elevation Model (GDEM) from Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Monthly surface water storage variations for 1993-2007 are presented, showing a strong seasonal and interannual variability, and are evaluated against in situ river discharge and precipitation. The basin-scale mean annual amplitude of approx. 1200 cu km is in the range of previous estimates and contributes to about half of the Gravity Recovery And Climate Experiment (GRACE) total water storage variations. For the first time, we map the surface water volume anomaly during the extreme droughts of 1997 (October-November) and 2005 (September-October) and found that during these dry events the water stored in the river and flood-plains of the Amazon basin was, respectively, approx. 230 (approx. 40%) and 210 (approx. 50%) cu km below the 1993-2007 average. This new 15year data set of surface water volume represents an unprecedented source of information for future hydrological or climate modeling of the Amazon. It is also a first step toward the development of such database at the global scale.

  9. Aerosol characteristics and particle production in the upper troposphere over the Amazon Basin

    Directory of Open Access Journals (Sweden)

    M. O. Andreae

    2018-01-01

    Full Text Available Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure often exceeding those in the planetary boundary layer (PBL by 1 or 2 orders of magnitude. The measurements were made during the German–Brazilian cooperative aircraft campaign ACRIDICON–CHUVA, where ACRIDICON stands for Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems and CHUVA is the acronym for Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (global precipitation measurement, on the German High Altitude and Long Range Research Aircraft (HALO. The campaign took place in September–October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation. Aerosol enhancements were observed consistently on all flights during which the UT was probed, using several aerosol metrics, including condensation nuclei (CN and cloud condensation nuclei (CCN number concentrations and chemical species mass concentrations. The UT particles differed sharply in their chemical composition and size distribution from those in the PBL, ruling out convective transport of combustion-derived particles from the boundary layer (BL as a source. The air in the immediate outflow of deep convective clouds was depleted of aerosol particles, whereas strongly enhanced number concentrations of small particles (< 90 nm diameter were found in UT regions that had experienced outflow from deep convection in the preceding 5–72 h. We also found elevated concentrations of larger (> 90 nm particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN. Our

  10. Aerosol characteristics and particle production in the upper troposphere over the Amazon Basin

    Science.gov (United States)

    Andreae, Meinrat O.; Afchine, Armin; Albrecht, Rachel; Amorim Holanda, Bruna; Artaxo, Paulo; Barbosa, Henrique M. J.; Borrmann, Stephan; Cecchini, Micael A.; Costa, Anja; Dollner, Maximilian; Fütterer, Daniel; Järvinen, Emma; Jurkat, Tina; Klimach, Thomas; Konemann, Tobias; Knote, Christoph; Krämer, Martina; Krisna, Trismono; Machado, Luiz A. T.; Mertes, Stephan; Minikin, Andreas; Pöhlker, Christopher; Pöhlker, Mira L.; Pöschl, Ulrich; Rosenfeld, Daniel; Sauer, Daniel; Schlager, Hans; Schnaiter, Martin; Schneider, Johannes; Schulz, Christiane; Spanu, Antonio; Sperling, Vinicius B.; Voigt, Christiane; Walser, Adrian; Wang, Jian; Weinzierl, Bernadett; Wendisch, Manfred; Ziereis, Helmut

    2018-01-01

    Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by 1 or 2 orders of magnitude. The measurements were made during the German-Brazilian cooperative aircraft campaign ACRIDICON-CHUVA, where ACRIDICON stands for Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems and CHUVA is the acronym for Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (global precipitation measurement), on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place in September-October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation. Aerosol enhancements were observed consistently on all flights during which the UT was probed, using several aerosol metrics, including condensation nuclei (CN) and cloud condensation nuclei (CCN) number concentrations and chemical species mass concentrations. The UT particles differed sharply in their chemical composition and size distribution from those in the PBL, ruling out convective transport of combustion-derived particles from the boundary layer (BL) as a source. The air in the immediate outflow of deep convective clouds was depleted of aerosol particles, whereas strongly enhanced number concentrations of small particles ( 90 nm) particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN. Our findings suggest a conceptual model, where production of new aerosol particles takes place in the continental UT from biogenic volatile organic material brought up by deep convection and converted to condensable

  11. The Amazon at sea: Onset and stages of the Amazon River from a marine record, with special reference to Neogene plant turnover in the drainage basin

    Science.gov (United States)

    Hoorn, Carina; Bogotá-A, Giovanni R.; Romero-Baez, Millerlandy; Lammertsma, Emmy I.; Flantua, Suzette G. A.; Dantas, Elton L.; Dino, Rodolfo; do Carmo, Dermeval A.; Chemale, Farid

    2017-06-01

    The Amazon submarine fan is a large sediment apron situated offshore Pará (Brazil) and represents the most distal extent of the Amazon River. The age of onset of this transcontinental river remains debated, yet is of great importance for understanding biotic evolutionary processes on land and at sea. Here we present new geochemical and palynological data from a borehole drilled at the continental slope and dated based on nannofossil biostratigraphy. We found that sediments of mixed source (craton and adjacent) occur at least from the late Oligocene (NP25) to late Miocene (NN9), and that the earliest Andes-derived sediments occur in NN10 (late Miocene). Our geochemical record indicates an onset of the transcontinental Amazon River between 9.4 and 9 Ma, which postdates the regional unconformity by 1 to 1.5 My. The shift in sediment geochemistry is more gradually replicated in the palynological record by a change from coastal plain and tropical lowland taxa to a mixture of tropical lowland, and montane forest to open Andean taxa. In particular, the appearance of taxa such as Jamesonia and Huperzia, followed by Valeriana, Polylepis-Acaena, Lysipomia and Plantago (with a current altitudinal range from 3200 to 4000 m) suggests the development of open, treeless, vegetation between 9.5 and 5.4 Ma, and highlight the presence of a high Andes in the late Miocene hinterland. Poaceae progressively increased from 9 Ma, with a notable rise from 4 Ma onwards, and percentages well above post-glacial and modern values, particularly between 2.6 and 0.8 Ma. We hypothesize that the rise of the grasses is a basin-wide phenomenon, but that the Plio-Pleistocene expansion of open, treeless vegetation on the Andean slopes and foothills are the main contributor. This rise in grasses was likely caused by climatic fluctuations, and subsequent changes in relief and erosion rates. We conclude that the onset of the Amazon River is coupled with Neogene Andean tectonism and that subsequent

  12. Mesozooplankton Graze on Cyanobacteria in the Amazon River Plume and Western Tropical North Atlantic

    Directory of Open Access Journals (Sweden)

    Brandon J. Conroy

    2017-08-01

    Full Text Available Diazotrophic cyanobacteria, those capable of fixing di-nitrogen (N2, are considered one of the major sources of new nitrogen (N in the oligotrophic tropical ocean, but direct incorporation of diazotrophic N into food webs has not been fully examined. In the Amazon River-influenced western tropical North Atlantic (WTNA, diatom diazotroph associations (DDAs and the filamentous colonial diazotrophs Trichodesmium have seasonally high abundances. We sampled epipelagic mesozooplankton in the Amazon River plume and WTNA in May–June 2010 to investigate direct grazing by mesozooplankton on two DDA populations: Richelia associated with Rhizosolenia diatoms (het-1 and Hemiaulus diatoms (het-2, and on Trichodesmium using highly specific qPCR assays targeting nitrogenase genes (nifH. Both DDAs and Trichodesmium occurred in zooplankton gut contents, with higher detection of het-2 predominantly in calanoid copepods (2.33–16.76 nifH copies organism-1. Abundance of Trichodesmium was low (2.21–4.03 nifH copies organism-1, but they were consistently detected at high salinity stations (>35 in calanoid copepods. This suggests direct grazing on DDAs, Trichodesmium filaments and colonies, or consumption as part of sinking aggregates, is common. In parallel with the qPCR approach, a next generation sequencing analysis of 16S rRNA genes identified that cyanobacterial assemblage associated with zooplankton guts was dominated by the non-diazotrophic unicellular phylotypes Synechococcus (56% and Prochlorococcus (26%. However, in two separate calanoid copepod samples, two unicellular diazotrophs Candidatus Atelocyanobacterium thalassa (UCYN-A and Crocosphaera watsonii (UCYN-B were present, respectively, as a small component of cyanobacterial assemblages (<2%. This study represents the first evidence of consumption of DDAs, Trichodesmium, and unicellular cyanobacteria by calanoid copepods in an area of the WTNA known for high carbon export. These diazotroph populations

  13. G6PD deficiency alleles in a malaria-endemic region in the Western Brazilian Amazon.

    Science.gov (United States)

    Dombrowski, Jamille G; Souza, Rodrigo M; Curry, Jonathan; Hinton, Laura; Silva, Natercia R M; Grignard, Lynn; Gonçalves, Ligia A; Gomes, Ana Rita; Epiphanio, Sabrina; Drakeley, Chris; Huggett, Jim; Clark, Taane G; Campino, Susana; Marinho, Claudio R F

    2017-06-15

    Plasmodium vivax parasites are the predominant cause of malaria infections in the Brazilian Amazon. Infected individuals are treated with primaquine, which can induce haemolytic anaemia in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals and may lead to severe and fatal complications. This X-linked disorder is distributed globally and is caused by allelic variants with a geographical distribution that closely reflects populations exposed historically to endemic malaria. In Brazil, few studies have reported the frequency of G6PD deficiency (G6PDd) present in malaria-endemic areas. This is particularly important, as G6PDd screening is not currently performed before primaquine treatment. The aim of this study was to determine the prevalence of G6PDd in the region of Alto do Juruá, in the Western Brazilian Amazon, an area characterized by a high prevalence of P. vivax infection. Five-hundred and sixteen male volunteers were screened for G6PDd using the fluorescence spot test (Beutler test) and CareStart™ G6PD Biosensor system. Demographic and clinical-epidemiological data were acquired through an individual interview. To assess the genetic basis of G6PDd, 24 SNPs were genotyped using the Kompetitive Allele Specific PCR assay. Twenty-three (4.5%) individuals were G6PDd. No association was found between G6PDd and the number of malaria cases. An increased risk of reported haemolysis symptoms and blood transfusions was evident among the G6PDd individuals. Twenty-two individuals had the G6PDd A(-) variant and one the G6PD A(+) variant. The Mediterranean variant was not present. Apart from one polymorphism, almost all SNPs were monomorphic or with low frequencies (0-0.04%). No differences were detected among ethnic groups. The data indicates that ~1/23 males from the Alto do Juruá could be G6PD deficient and at risk of haemolytic anaemia if treated with primaquine. G6PD A(-) is the most frequent deficiency allele in this population. These results concur

  14. Seasonal and spatial contrasts of sedimentary organic carbon in floodplain lakes of the central Amazon basin.

    Science.gov (United States)

    Sobrinho, Rodrigo; Kim, Jung-Hyun; Abril, Gwenaël; Zell, Claudia; Moreira-Turcq, Patricia; Mortillaro, Jean-Michel; Meziane, Tarik; Damsté, Jaap; Bernardes, Marcelo

    2014-05-01

    Three-quarters of the area of flooded land in the world are temporary wetlands (Downing, 2009), which play a significant role in the global carbon cycle(Einsele et al., 2001; Cole et al., 2007; Battin et al., 2009; Abril et al., 2013). Previous studies of the Amazonian floodplain lakes (várzeas), one important compartment of wetlands, showed that the sedimentation of organic carbon (OC) in the floodplain lakes is strongly linked to the periodical floods and to the biogeography from upstream to downstream(Victoria et al., 1992; Martinelli et al., 2003). However, the main sources of sedimentary OC remain uncertain. Hence, the study of the sources of OC buried in floodplain lake sediments can enhance our understanding of the carbon balance of the Amazon ecosystems. In this study, we investigated the seasonal and spatial pattern of sedimentary organic matter in five floodplain lakes of the central Amazon basin (Cabaliana, Janauaca, Canaçari, Miratuba, and Curuai) which have different morphologies, hydrodynamics and vegetation coverage. Surface sediments were collected in four hydrological seasons: low water (LW), rising water (RW), high water (HW) and falling water (FW) in 2009 and 2010. We investigated commonly used bulk geochemical tracers such as C:N ratio and stable isotopic composition of organic carbon (δ13COC). These results were compared with lignin-phenol parameters as an indicator of vascular plant detritus (Hedges and Ertel, 1982) and branched glycerol dialkyl glycerol tetraethers (brGDGTs) to trace the soil OC from land to the aquatic settings (Hopmans et al., 2004). Our data showed that during the RW and FW seasons, the concentration of lignin and brGDGTs were higher in comparison to other seasons. Our study also indicated that floodplain lake sediments primarily consisted of a mixture of C3 plant detritus and soil OC. However, a downstream increase in C4 plant-derived OC contribution was observed along the gradient of increasingly open waters, i

  15. A new subterranean species of Phreatobius Goeldi, 1905 (Siluriformes, Incertae sedis from the Southwestern Amazon basin

    Directory of Open Access Journals (Sweden)

    Oscar Akio Shibatta

    2007-01-01

    Full Text Available A new species of the previously monotypic catfish genus Phreatobius is described from an artificial well in the village of Rio Pardo, located 90 km south of the city of Porto Velho, State of Rondônia, Brazil, in the drainage area of the Rio Branco (Rio Madeira system, Amazon basin. Phreatobius dracunculus n. sp. differs from its only congener, P. cisternarum, by the absence of eyes (vs. present, the lack of dark integumentary pigmentation (vs. faint dark pigment always present, the presence of five pectoral-fin rays (vs. four, ventral procurrent rays 11-13 (vs. 22 to 26, dorsal procurrent rays 29-31 (vs. 42 to 50, fewer vertebrae (52 or 53 vs. 59 to 64 and the larger pseudotympanus. The new species shows all diagnostic characters so far proposed for Phreatobius, including an unusual red coloration in life. The localities of the two species of Phreatobius are approximately 1900 km apart. That, in association with their peculiar and mostly inaccessible habitats, indicates that the genus may be widely distributed in the Amazon basin.Uma nova espécie do gênero previamente monotípico Phreatobius é descrita de um poço artificial no Povoado de Rio Pardo, localizado 90 km ao sul da cidade de Porto Velho, Estado de Rondônia, Brasil, na área de drenagem do rio Branco (sistema do Rio Madeira, bacia Amazônica. Phreatobius dracunculus sp. n. difere da única espécie congênere, P. cisternarum, pela ausência de olhos (vs. presente, ausência de pigmentação na pele (vs. algum pigmento escuro sempre presente, presença de cinco raios na nadadeira peitoral (vs. 4, menor número de raios procorrentes ventrais 11-13 (vs. 22 a 26, e menor número de raios procorrentes dorsais 29-31 (vs. 42 a 50, menor número de vértebras (52 ou 53 vs. 59 a 64 e pseudotímpano maior. A nova espécie apresenta todos os caracteres diagnósticos propostos para Phreatobius, incluindo a conspícua coloração vermelha em vida. As localidades das duas espécies de

  16. LBA-ECO LC-07 Monthly Mean Flooded Wetlands Habitat, Central Amazon Basin: 1979-1996

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set reports monthly mean inundation areas (square kilometers) for four cover classes of Central Amazon wetlands habitat: Open water (OW), river channel...

  17. LBA-ECO LC-07 Reflectance Spectra and Water Quality of Amazon Basin Floodplain Lakes

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes bidirectional reflectance (BDR) spectra and water-quality data of floodplain lakes of the Solimoes and Negro Rivers in the central Amazon...

  18. LBA-ECO CD-34 Hyperion 30-m Surface Reflectance, Amazon Basin: 2002-2005

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains 20 multispectral surface reflectance images collected by the EO-1 satellite Hyperion sensor at 30-m resolution and covering the entire Amazon...

  19. Stability in a changing world - palm community dynamics in the hyperdiverse western Amazon over 17 years.

    Science.gov (United States)

    Olivares, Ingrid; Svenning, Jens-Christian; van Bodegom, Peter M; Valencia, Renato; Balslev, Henrik

    2017-03-01

    Are the hyperdiverse local forests of the western Amazon undergoing changes linked to global and local drivers such as climate change, or successional dynamics? We analyzed local climatic records to assess potential climatic changes in Yasuní National Park, Ecuador, and compared two censuses (1995, 2012) of a palm community to assess changes in community structure and composition. Over 17 years, the structure and composition of this palm community remained remarkably stable. Soil humidity was significantly lower and canopy conditions were significantly more open in 2012 compared to 1995, but local climatic records showed that no significant changes in precipitation, temperature or river level have occurred during the last decade. Thus, we found no evidence of recent directional shifts in climate or the palm community in Yasuní. The absence of changes in local climate and plant community dynamics in Yasuní contrasts with recent findings from eastern Amazon, where environmental change is driving significant changes in ecosystem dynamics. Our findings suggest that until now, local forests in the northwest Amazon may have escaped pressure from climate change. The stability of this rich palm community embedded in the hyperdiverse Yasuní National Park underlines its uniqueness as a sanctuary for the protection of Amazonian diversity from global change impacts. © 2016 John Wiley & Sons Ltd.

  20. A Comprehensive Analysis of Parameter Sensitivity and Land Surface Model Optimization for the Amazon Basin

    Science.gov (United States)

    Rosolem, R.; Shuttleworth, W. J.; Gupta, H. V.; Goncalves, L.; Zeng, X.; Restrepo-Coupe, N.

    2010-12-01

    About eight years of data (1999-2006) collected from a variety of sites located in the Amazon basin under the Large-scale Biosphere-Atmosphere experiment in Amazonia (LBA) are now being used to compare a large number of land surface parameterization (LSP) schemes as part of the LBA Data-Model Intercomparison Project (LBA-DMIP). We use continuous hourly meteorological data obtained from the LBA-DMIP to drive the third generation of the Simple Biosphere model (SiB3), and to conduct a comprehensive parameter estimation study in the region. The validation data comprise of sensible and latent heat flux densities (i.e., H and LE, respectively) and Net Ecosystem Exchange of CO2 (i.e., NEE). Given the large number of parameters found in current LSP schemes (such as SiB3), manual calibration can be intractable and, consequently, automatic calibration techniques have become the preferred alternative. Parameter sensitivity analysis contributes to the understanding of potential structural characteristics of a model, and also reduces the dimension of the optimization problem by fixing insensitive parameters to their nominal values. In this study, we use the variance-based Sobol sensitivity analysis approach which determines the sensitivity of each parameter based on its percent contribution to the total output variance in the model. We then conduct the optimization of the most significant parameters in SiB3 using the so called “A Multi-Algorithm, Genetically Adaptive Multiobjective” (AMALGAM) which combines two highly desired concepts in evolutionary algorithms: (1) simultaneous multimethod search, and (2) self-adaptive offspring creation. The ultimate goal of this study is to identify key parameters related to individual LBA sites that need to be properly analyzed and calibrated in order to improve simulated land surface processes in the region. We anticipate that this will also help how measurements of these parameters are obtained in situ. The performance of SiB3 prior

  1. Carbon isotope discrimination in forest and pasture ecosystems of the Amazon Basin, Brazil

    Science.gov (United States)

    Ometto, Jean P. H. B.; Flanagan, Lawrence B.; Martinelli, Luiz A.; Moreira, Marcelo Z.; Higuchi, Niro; Ehleringer, James R.

    2002-12-01

    Our objective was to measure the stable carbon isotope composition of leaf tissue and CO2 released by respiration (δr), and to use this information as an estimate of changes in ecosystem isotopic discrimination that occur in response to seasonal and interannual changes in environmental conditions, and land-use change (forest-pasture conversion). We made measurements in primary forest and pastures in the Amazon Basin of Brazil. At the Santarém forest site, δr values showed a seasonal cycle varying from less than -29‰ to approximately -26‰. The observed seasonal change in δr was correlated with variation in the observed monthly precipitation. In contrast, there was no significant seasonal variation in δr at the Manaus forest site (average δr approximately -28‰), consistent with a narrower range of variation in monthly precipitation than occurred in Santarém. Despite substantial (9‰) vertical variation in leaf δ13C, the average δr values observed for all forest sites were similar to the δ13C values of the most exposed sun foliage of the dominant tree species. This suggested that the major portion of recently respired carbon dioxide in these forests was metabolized carbohydrate fixed by the sun leaves at the top of the forest canopy. There was no significant seasonal variation observed in the δ13C values of leaf organic matter for the forest sites. We sampled in pastures dominated by the C4 grass, Brachiaria spp., which is planted after forest vegetation has been cleared. The carbon isotope ratio of respired CO2 in pastures was enriched in 13C by approximately 10‰ compared to forest ecosystems. A significant temporal change occurred in δr after the Manaus pasture was burned. Burning removed much of the encroaching C3 shrub vegetation and so allowed an increased dominance of the C4 pasture grass, which resulted in higher δr values.

  2. Molecular Epidemiology of Giardia, Blastocystis and Cryptosporidium among Indigenous Children from the Colombian Amazon Basin

    Science.gov (United States)

    Sánchez, Angie; Munoz, Marina; Gómez, Natalia; Tabares, Juan; Segura, Laura; Salazar, Ángela; Restrepo, Cristian; Ruíz, Miguel; Reyes, Patricia; Qian, Yuchen; Xiao, Lihua; López, Myriam C.; Ramírez, Juan D.

    2017-01-01

    The incidence and prevalence of intestinal parasites in children is most likely due to lack of natural or acquired resistance and differences in behavior and habits closely related to environmental and socioeconomic determinants. The most important protozoa that parasitize humans are Giardia, Entamoeba, Blastocystis, and Cryptosporidium. These parasites present wide intraspecific genetic diversity and subsequently classified into assemblages and subtypes. The Amazon basin is the largest in the world and is the fifth freshwater reserve on the planet. Contradictorily, people living in these areas (Indigenous populations) have poor quality of life, which favors the infection of diseases of fecal-oral transmission. The aim of this work was to unravel the molecular epidemiology of Giardia, Blastocystis and Cryptosporidium across four communities (Puerto Nariño, San Juan del Soco, Villa Andrea and Nuevo Paraíso). We obtained 284 fecal samples from children under 15 years old that were analyzed by direct microscopy (261 samples) and Real Time PCR (qPCR) (284 samples). The positive samples for these protozoa were further characterized by several molecular markers to depict assemblages and subtypes. We observed a frequency of Giardia infection by microscopy of 23.7% (62 samples) and by qPCR of 64.8% (184 samples); for Blastocystis by microscopy of 35.2% (92 samples) and by qPCR of 88.7% (252 samples) and for Cryptosporidium only 1.9% (5 samples) were positive by microscopy and qPCR 1.8% (5 samples). Regarding the Giardia assemblages, using the glutamate dehydrogenase (gdh) marker we observed AI, BIII and BIV assemblages and when using triose phosphate isomerase (tpi) we observed assemblages AI, AII, BIII and BIV. In contrast, Blastocystis STs detected were 1, 2, 3, 4, and 6. Lastly, the species C. viatorum, C. hominis (with the subtypes IdA19 and IaA12R8) and C. parvum (with the subtype IIcA5G3c) were identified. We observed a high profile of zoonotic transmission

  3. Pfatp6 molecular profile of Plasmodium falciparum isolates in the western Brazilian Amazon.

    Science.gov (United States)

    Brasil, Larissa W; Areas, André L L; Melo, Gisely C; Oliveira, Cintia M C; Alecrim, Maria G C; Lacerda, Marcus V G; O'Brien, Connor; Oelemann, Walter M R; Zalis, Mariano G

    2012-04-10

    Anti-malarial drug resistance has emerged as one of the biggest challenges confronting the worldwide effort to control malaria. The appearance of chloroquine and multi-drug resistance had devastating effects on therapeutic efficacy of former first-line agents. Artemisinin has proven to be an excellent therapeutic alternative to fill the void in chemotherapeutic options left by resistance mechanisms. At the time of introduction, no resistance to artemisinins had been recorded, and artemisinins demonstrated excellent parasite reduction rates. In an attempt to protect artemisinin efficacy, the World Health Organization (WHO) made artemisinin-based combination therapy (ACT) its official first-line treatment recommendation for uncomplicated Plasmodium falciparum in 2006. In Brazil, artemether/lumefantrine became the Brazilian Malaria Control Programme's official treatment recommendation in 2007. The sarco/endoplasmic reticulum Ca2+ - ATPase ortholog of P. falciparum (pfatp6) has been suggested as one of the targets of artemisinins. Consequently, pfatp6 gene polymorphisms are being investigated as markers of artemisinin resistance elsewhere. The goal of this work was to describe the molecular profile of pfatp6 in P. falciparum isolates from different localities in the Amazonas State. DNA polymorphisms of the pfatp6 gene in 80 P. falciparum isolates from 11 municipalities of the Amazonas State (Western Brazilian Amazon), before and after the introduction of ACT in the Brazilian anti-malarial guidelines, were analysed by automatic sequencing. Mutations in the pfatp6 gene were searched using Mutation Surveyor v3.25 software. The P. falciparum pfatp6 gene presented polymorphisms at codons 37, 630 and 898. The R37K mutation was found in 16% of the samples, A630S in 32% and I898I in 52%. No S769N mutation, however, was detected in the analysed samples. Despite the small number of samples, data presented here provide baseline information about polymorphisms of pfatp6 gene

  4. Pfatp6 molecular profile of Plasmodium falciparum isolates in the western Brazilian Amazon

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    Brasil Larissa W

    2012-04-01

    Full Text Available Abstract Background Anti-malarial drug resistance has emerged as one of the biggest challenges confronting the worldwide effort to control malaria. The appearance of chloroquine and multi-drug resistance had devastating effects on therapeutic efficacy of former first-line agents. Artemisinin has proven to be an excellent therapeutic alternative to fill the void in chemotherapeutic options left by resistance mechanisms. At the time of introduction, no resistance to artemisinins had been recorded, and artemisinins demonstrated excellent parasite reduction rates. In an attempt to protect artemisinin efficacy, the World Health Organization (WHO made artemisinin-based combination therapy (ACT its official first-line treatment recommendation for uncomplicated Plasmodium falciparum in 2006. In Brazil, artemether/lumefantrine became the Brazilian Malaria Control Programme's official treatment recommendation in 2007. The sarco/endoplasmic reticulum Ca2+ - ATPase ortholog of P. falciparum (pfatp6 has been suggested as one of the targets of artemisinins. Consequently, pfatp6 gene polymorphisms are being investigated as markers of artemisinin resistance elsewhere. The goal of this work was to describe the molecular profile of pfatp6 in P. falciparum isolates from different localities in the Amazonas State. Methods DNA polymorphisms of the pfatp6 gene in 80 P. falciparum isolates from 11 municipalities of the Amazonas State (Western Brazilian Amazon, before and after the introduction of ACT in the Brazilian anti-malarial guidelines, were analysed by automatic sequencing. Mutations in the pfatp6 gene were searched using Mutation Surveyor v3.25 software. Results The P. falciparum pfatp6 gene presented polymorphisms at codons 37, 630 and 898. The R37K mutation was found in 16% of the samples, A630S in 32% and I898I in 52%. No S769N mutation, however, was detected in the analysed samples. Conclusion Despite the small number of samples, data presented here

  5. Amazon Plume Salinity Response to Ocean Teleconnections

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    Pedro Tyaquiçã

    2017-08-01

    Full Text Available Pacific and Atlantic sea surface temperature (SST variability strongly influences rainfall changes in the Amazon River basin, which impacts on the river discharge and consequently the sea surface salinity (SSS in the Amazon plume. An Empirical Orthogonal Function (EOF analysis was performed using 46 years of SST, rainfall, and SSS datasets, in order to establish the relationship between these variables. The first three modes of SST/rainfall explained 87.83% of the total covariance. Pacific and Atlantic SSTs led Amazon basin rainfall events by 4 months. The resultant SSS in the western tropical North Atlantic (WTNA lagged behind basin rainfall by 3 months, with 75.04% of the total covariance corresponding to the first four EOF modes. The first EOF mode indicated a strong SSS pattern along the coast that was connected to negative rainfall anomalies covering the Amazon basin, linked to El Niño events. A second pattern also presented positive SSS anomalies, when the rainfall was predominantly over the northwestern part of the Amazon basin, with low rainfall around the Amazon River mouth. The pattern with negative SSS anomalies in the WTNA was associated with the fourth mode, when positive rainfall anomalies were concentrated in the northwest part of South America. The spatial rainfall structure of this fourth mode was associated with the spatial rainfall distribution found in the third EOF mode of SST vs. rainfall, which was a response to La Niña Modoki events. A statistical analysis for the 46 year period and monthly anomaly composites for 2008 and 2009 indicated that La Niña Modoki events can be used for the prediction of low SSS patterns in the WNTA.

  6. Hydrological modeling of the Peruvian–Ecuadorian Amazon Basin using GPM-IMERG satellite-based precipitation dataset

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    R. Zubieta

    2017-07-01

    Full Text Available In the last two decades, rainfall estimates provided by the Tropical Rainfall Measurement Mission (TRMM have proven applicable in hydrological studies. The Global Precipitation Measurement (GPM mission, which provides the new generation of rainfall estimates, is now considered a global successor to TRMM. The usefulness of GPM data in hydrological applications, however, has not yet been evaluated over the Andean and Amazonian regions. This study uses GPM data provided by the Integrated Multi-satellite Retrievals (IMERG (product/final run as input to a distributed hydrological model for the Amazon Basin of Peru and Ecuador for a 16-month period (from March 2014 to June 2015 when all datasets are available. TRMM products (TMPA V7 and TMPA RT datasets and a gridded precipitation dataset processed from observed rainfall are used for comparison. The results indicate that precipitation data derived from GPM-IMERG correspond more closely to TMPA V7 than TMPA RT datasets, but both GPM-IMERG and TMPA V7 precipitation data tend to overestimate, compared to observed rainfall (by 11.1 and 15.7 %, respectively. In general, GPM-IMERG, TMPA V7 and TMPA RT correlate with observed rainfall, with a similar number of rain events correctly detected ( ∼  20 %. Statistical analysis of modeled streamflows indicates that GPM-IMERG is as useful as TMPA V7 or TMPA RT datasets in southern regions (Ucayali Basin. GPM-IMERG, TMPA V7 and TMPA RT do not properly simulate streamflows in northern regions (Marañón and Napo basins, probably because of the lack of adequate rainfall estimates in northern Peru and the Ecuadorian Amazon.

  7. Hydrological modeling of the Peruvian-Ecuadorian Amazon Basin using GPM-IMERG satellite-based precipitation dataset

    Science.gov (United States)

    Zubieta, Ricardo; Getirana, Augusto; Carlo Espinoza, Jhan; Lavado-Casimiro, Waldo; Aragon, Luis

    2017-07-01

    In the last two decades, rainfall estimates provided by the Tropical Rainfall Measurement Mission (TRMM) have proven applicable in hydrological studies. The Global Precipitation Measurement (GPM) mission, which provides the new generation of rainfall estimates, is now considered a global successor to TRMM. The usefulness of GPM data in hydrological applications, however, has not yet been evaluated over the Andean and Amazonian regions. This study uses GPM data provided by the Integrated Multi-satellite Retrievals (IMERG) (product/final run) as input to a distributed hydrological model for the Amazon Basin of Peru and Ecuador for a 16-month period (from March 2014 to June 2015) when all datasets are available. TRMM products (TMPA V7 and TMPA RT datasets) and a gridded precipitation dataset processed from observed rainfall are used for comparison. The results indicate that precipitation data derived from GPM-IMERG correspond more closely to TMPA V7 than TMPA RT datasets, but both GPM-IMERG and TMPA V7 precipitation data tend to overestimate, compared to observed rainfall (by 11.1 and 15.7 %, respectively). In general, GPM-IMERG, TMPA V7 and TMPA RT correlate with observed rainfall, with a similar number of rain events correctly detected ( ˜ 20 %). Statistical analysis of modeled streamflows indicates that GPM-IMERG is as useful as TMPA V7 or TMPA RT datasets in southern regions (Ucayali Basin). GPM-IMERG, TMPA V7 and TMPA RT do not properly simulate streamflows in northern regions (Marañón and Napo basins), probably because of the lack of adequate rainfall estimates in northern Peru and the Ecuadorian Amazon.

  8. Use of GNSS data for Hydrology: Applications of the method PPP (Precise Point Positioning) with integer ambiguities fixing for hydrological studies in the Amazon basin

    Science.gov (United States)

    Moreira, D. M.; Calmant, S.; Perosanz, F.; Santos, A.; Santos Da Silva, J.; Seyler, F.; Ramillien, G. L.; Monteiro, A.; Rotunno, O.; Shum, C.

    2011-12-01

    Applications of GNSS data is constantly being used in hydrology. One of the key applications is the characterization of river's longitudinal profiles, an information required to develop hydrological and hydrodynamic studies and to evaluate the quality of data obtained through space altimetry techniques. Some factors illustrate the challenge of establishing quality altimetry data from a GNSS receivers to obtain rivers profiles in Amazon Basin. GNSS reference network is sparse, the distance between survey points and reference stations is large, rivers have an extension of several thousands of kilometers. All these factors contribute in limiting the efficiency of classical techniques of GNSS data processing like double difference. In the present work we use the Gins-PC software developed at CNES / GRGS. We discuss the capability of the PPP kinematic with integer ambiguities fixing strategy implemented in GINS-PC in processing GPS data to calculate river's longitudinal profiles in the Amazon Basin. The profiles will be processed using data obtained from GPS receivers on boarding boats along the rivers of Amazon Basin such as Negro river, Madeira river and Amazon/Solimões river. For this purpose, field campaings were conducted between 2005 and 2010 by ANA ( Brazilian National Water Agency), CPRM (Brazilian Geologic Survey), IRD (French Institute of Research by Development), Hybam ( Hydrology of Amazon Basin), PROSUL (Research project by CNPQ/UFRJ) and FOAM (From Ocean to inland waters Altimetry Monitoring) river section project. Under the proposed framework, these profiles will be then compared with profiles obtained by water level variation data using altimetry data from tracks of the Jason-2 and ENVISAT missions. The profiles will be also used to levelling some gauge stations in Amazon Basin and gauge data will be used to obtain a temporal variation of these profiles. However some gauges are strongly affected by charge effects, mainly caused by the hydrological cycle

  9. Impacts of future deforestation and climate change on the hydrology of the Amazon Basin

    NARCIS (Netherlands)

    Guimberteau, Matthieu; Ciais, Philippe; Pablo Boisier, Juan; Paula Dutra Aguiar, Ana; Biemans, Hester; Deurwaerder, De Hannes; Galbraith, David; Kruijt, Bart; Langerwisch, Fanny; Poveda, German; Rammig, Anja; Andres Rodriguez, Daniel; Tejada, Graciela; Thonicke, Kirsten; Randow, Von Celso; Randow, Rita; Zhang, Ke; Verbeeck, Hans

    2017-01-01

    Deforestation in Amazon is expected to decrease evapotranspiration (ET) and to increase soil moisture and river discharge under prevailing energy-limited conditions. The magnitude and sign of the response of ET to deforestation depend both on the magnitude and regional patterns of land-cover change

  10. Upper Devonian microvertebrates from the Canning Basin, Western Australia

    Science.gov (United States)

    Roelofs, Brett; Playton, Ted; Barham, Milo; Trinajstic, Kate

    2015-03-01

    A diverse microvertebrate fauna is described from the Virgin Hills and Napier formations, Bugle Gap Limestone Canning Basin, Western Australia. Measured sections at Horse Spring and Casey Falls (Virgin Hills Formation) and South Oscar Range (Napier Formation) comprise proximal to distal slope carbonates ranging in age from the Late Devonian Frasnian to middle Famennian. A total of 18 chondrichthyan taxa are identified based on teeth, including the first record of Thrinacodus tranquillus, Cladoides wildungensis, Protacrodus serra and Lissodus lusavorichi from the Canning Basin. A new species, Diademodus dominicus sp. nov. is also described and provides the first record of this genus outside of Laurussia. In addition, the upper range of Australolepis seddoni has been extended to Late Devonian conodont Zone 11, making it the youngest known occurrence for this species. The Virgin Hills and Napier formations microvertebrate faunas show close affinities to faunas recovered from other areas of Gondwana, including eastern Australia, Iran, Morocco and South China, which is consistent with known conodont and trilobite faunas of the same age.

  11. Outcomes of pregnancy among women living in the proximity of oil fields in the Amazon basin of Ecuador.

    Science.gov (United States)

    San Sebastián, Miguel; Armstrong, Ben; Stephens, Carolyn

    2002-01-01

    Oil companies have released billions of gallons of untreated wastes and oil directly into the environment of the Ecuadorian Amazon. This cross-sectional study investigated the environmental conditions and reproductive health of women living in rural communities surrounded by oil fields in the Amazon basin and in unexposed communities. Water from local streams was analyzed for total petroleum hydrocarbons (TPH). The women, aged 17 to 45 years, had resided for at least three years in the study communities. Socioeconomic and reproductive histories of the last three pregnancies were obtained from interviews. Information from the questionnaire was available for 365 exposed and 283 non-exposed women. The study was conducted from November 1998 to April 1999. Streams of exposed communities had TPH concentrations above the allowable limit. After adjustment for potential confounders, the pregnancies of women in exposed communities were more likely to end in spontaneous abortion (OR: 2.47; 95% CI: 1.61-3.79; p < 0.01). No association was found between stillbirth and exposure. An environmental system to control and eliminate the sources of pollution in the area is needed.

  12. Influence of seasonality on the interaction of mercury with aquatic humic substances extracted from the Middle Negro River Basin (Amazon)

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luciana C. de, E-mail: lcamargo@ufscar.br [Federal University of Sao Carlos (UFSCar), Sorocaba, SP (Brazil); Botero, Wander G. [Federal University of Alagoas (UFAL), Arapiraca, AL (Brazil); Santos, Felipe A. [Institute of Biosciences, Sao Paulo State University (UNESP), Botucatu, SP (Brazil); Sargentini Junior, Ezio [National Amazon Research Institute (INPA), Manaus, AM (Brazil); Rocha, Julio C.; Santos, Ademir dos [Institute of Chemistry of Araraquara, Sao Paulo State University (UNESP), Araraquara, SP (Brazil)

    2012-09-15

    High mercury concentrations in different environmental matrices in the Amazon have been attributed to mining activities. However, high concentrations of mercury are also present in the soil and water in places like in the middle of the Negro River Basin, which is far away from any anthropogenic emission sources. The Amazon region is characterized by two different regional seasons, with well-defined flood and low water periods. The objective of this work was to investigate the seasonal influences of the interaction between mercury and aquatic humic substances (AHS), which are the main agents of the natural organic complexation capacity. The results of the multivariate statistical analysis of the data showed that the humic substances had different structural characteristics, depending on each season. The ability of humic substances to form complexes with Hg(II) is not directly related to their carbon content, but to the nature and availability of the functional groups present in its structure. The functional groups are carboxylic and aromatic directly related to the higher complexation capacity of AHS by mercury ions. (author)

  13. Canopy-scale biophysical controls of transpiration and evaporation in the Amazon Basin

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    K. Mallick

    2016-10-01

    Full Text Available Canopy and aerodynamic conductances (gC and gA are two of the key land surface biophysical variables that control the land surface response of land surface schemes in climate models. Their representation is crucial for predicting transpiration (λET and evaporation (λEE flux components of the terrestrial latent heat flux (λE, which has important implications for global climate change and water resource management. By physical integration of radiometric surface temperature (TR into an integrated framework of the Penman–Monteith and Shuttleworth–Wallace models, we present a novel approach to directly quantify the canopy-scale biophysical controls on λET and λEE over multiple plant functional types (PFTs in the Amazon Basin. Combining data from six LBA (Large-scale Biosphere-Atmosphere Experiment in Amazonia eddy covariance tower sites and a TR-driven physically based modeling approach, we identified the canopy-scale feedback-response mechanism between gC, λET, and atmospheric vapor pressure deficit (DA, without using any leaf-scale empirical parameterizations for the modeling. The TR-based model shows minor biophysical control on λET during the wet (rainy seasons where λET becomes predominantly radiation driven and net radiation (RN determines 75 to 80 % of the variances of λET. However, biophysical control on λET is dramatically increased during the dry seasons, and particularly the 2005 drought year, explaining 50 to 65 % of the variances of λET, and indicates λET to be substantially soil moisture driven during the rainfall deficit phase. Despite substantial differences in gA between forests and pastures, very similar canopy–atmosphere "coupling" was found in these two biomes due to soil moisture-induced decrease in gC in the pasture. This revealed the pragmatic aspect of the TR-driven model behavior that exhibits a high sensitivity of gC to per unit change in wetness as opposed to gA that is marginally sensitive to

  14. Late Miocene onset of the Amazon River and the Amazon deep-sea fan: Evidence from the Foz do Amazonas Basin

    NARCIS (Netherlands)

    Figueiredo, J.; Hoorn, C.; van der Ven, P.; Soares, E.

    2009-01-01

    New biostratigraphic, isotopic, and well log data from exploration wells on the outer continental shelf and uppermost Amazon deep-sea fan, Brazil, reveal that the Amazon River was initiated as a transcontinental river between 11.8 and 11.3 Ma ago (middle to late Miocene), and reached its present

  15. Past terrestrial water storage (1980–2008 in the Amazon Basin reconstructed from GRACE and in situ river gauging data

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    M. Becker

    2011-02-01

    Full Text Available Terrestrial water storage (TWS composed of surface waters, soil moisture, groundwater and snow where appropriate, is a key element of global and continental water cycle. Since 2002, the Gravity Recovery and Climate Experiment (GRACE space gravimetry mission provides a new tool to measure large-scale TWS variations. However, for the past few decades, direct estimate of TWS variability is accessible from hydrological modeling only. Here we propose a novel approach that combines GRACE-based TWS spatial patterns with multi-decadal-long in situ river level records, to reconstruct past 2-D TWS over a river basin. Results are presented for the Amazon Basin for the period 1980–2008, focusing on the interannual time scale. Results are compared with past TWS estimated by the global hydrological model ISBA-TRIP. Correlations between reconstructed past interannual TWS variability and known climate forcing modes over the region (e.g., El Niño-Southern Oscillation and Pacific Decadal Oscillation are also estimated. This method offers new perspective for improving our knowledge of past interannual TWS in world river basins where natural climate variability (as opposed to direct anthropogenic forcing drives TWS variations.

  16. Evaluation of drought indices at interannual to climate change timescales: a case study over the Amazon and Mississippi river basins

    Science.gov (United States)

    Joetzjer, E.; Douville, H.; Delire, C.; Ciais, P.; Decharme, B.; Tyteca, S.

    2012-11-01

    The present study compares three meteorological drought indices (scPDSI, SPI and SPEI respectively) and their ability to account for the variations of annual mean river discharge on both interannual and climate change timescales. The Standardized Runoff Index (SRI) is used as a proxy of river discharge. The Mississippi and Amazon river basins provide two contrasted testbeds for this analysis. All meteorological drought indices are derived from monthly 2-meter temperature and/or precipitation, using either gridded observations or outputs of a global climate model. The SPI based solely on precipitation is not outperformed by the SPEI (accounting for potential evapotranspiration) and the scPDSI (based on a simplified water balance) at detecting interannual SRI variations. Under increasing concentrations of greenhouse gases, the simulated response of the areal fraction in drought is highly index-dependent, suggesting that more physical water balance models are needed to account for the impact of global warming on hydrological droughts.

  17. Anatomy and systematics of Anodontites Elongatus (Swainson from Amazon and Parana Basins, Brazil (Mollusca, Bivalvia, Unionoida, Mycetopodidae

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    Luiz Ricardo L Simone

    1997-12-01

    Full Text Available The anatomy of Anodontiies elongatus (Swainson, 1823, a rare species restricted to the Amazon and Parana Basins, is described by first time, showing a group of conchological and anatomical characters exclusive of this species that may be analyzed to identify it. Diagnosis of A. elongatus: shell long antero-posteriorly, umbones prominent, periostracum opaque and smooth, two posterior radial striae; middle fold of mantle edge veiy tall; gill long antero-posteriorly and short dorso-ventrally, extending about a half of it total length beyond visceral mass; palps proportionally small, several furrows in its outer surface; stomach without esophageal transversal ridjp, dorsal hood and gastric shield poorly developed, major typhlosole entering in ddd , posterior pouch of sa³ very-long; style sac reduced, without crystalline style; distal region of intestine and rectum with a well developed typhlosole, "T" in section, other intestinal regions without folds; gonad gonochoristic.

  18. Placentation in dolphins from the Amazon River Basin: the Boto, Inia geoffrensis, and the Tucuxi, Sotalia fluviatilis.

    Science.gov (United States)

    da Silva, Vera M F; Carter, Anthony M; Ambrosio, Carlos E; Carvalho, Ana F; Bonatelli, Marina; Lima, Marcelo C; Miglino, Maria Angelica

    2007-06-28

    A recent reassessment of the phylogenetic affinities of cetaceans makes it timely to compare their placentation with that of the artiodactyls. We studied the placentae of two sympatric species of dolphin from the Amazon River Basin, representing two distinct families. The umbilical cord branched to supply a bilobed allantoic sac. Small blood vessels and smooth muscle bundles were found within the stroma of the cord. Foci of squamous metaplasia occurred in the allanto-amnion and allantochorion. The interhemal membrane of the placenta was of the epitheliochorial type. Two different types of trophoblastic epithelium were seen. Most was of the simple columnar type and indented by fetal capillaries. However, there were also areolar regions with tall columnar trophoblast and these were more sparsely supplied with capillaries. The endometrium was well vascularised and richly supplied with actively secreting glands. These findings are consistent with the current view that Cetacea are nested within Artiodactyla as sister group to the hippopotamids.

  19. Placentation in dolphins from the Amazon River Basin: the Boto, Inia geoffrensis, and the Tucuxi, Sotalia fluviatilis

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    Bonatelli Marina

    2007-06-01

    Full Text Available Abstract A recent reassessment of the phylogenetic affinities of cetaceans makes it timely to compare their placentation with that of the artiodactyls. We studied the placentae of two sympatric species of dolphin from the Amazon River Basin, representing two distinct families. The umbilical cord branched to supply a bilobed allantoic sac. Small blood vessels and smooth muscle bundles were found within the stroma of the cord. Foci of squamous metaplasia occurred in the allanto-amnion and allantochorion. The interhemal membrane of the placenta was of the epitheliochorial type. Two different types of trophoblastic epithelium were seen. Most was of the simple columnar type and indented by fetal capillaries. However, there were also areolar regions with tall columnar trophoblast and these were more sparsely supplied with capillaries. The endometrium was well vascularised and richly supplied with actively secreting glands. These findings are consistent with the current view that Cetacea are nested within Artiodactyla as sister group to the hippopotamids.

  20. An initial examination of the epidemiology of malaria in the State of Roraima, in the Brazilian Amazon Basin

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    CHAVES Sandra S.

    2000-01-01

    Full Text Available This study firstly describes the epidemiology of malaria in Roraima, Amazon Basin in Brazil, in the years from 1991 to 1993: the predominance of plasmodium species, distribution of the blood slides examined, the malaria risk and seasonality; and secondly investigates whether population growth from 1962 to 1993 was associated with increasing risk of malaria. Frequency of malaria varied significantly by municipality. Marginally more malaria cases were reported during the dry season (from October to April, even after controlling for by year and municipality. Vivax was the predominant type in all municipalities but the ratio of plasmodium types varied between municipalities. No direct association between population growth and increasing risk of malaria from 1962 to 1993 was detected. Malaria in Roraima is of the "frontier" epidemiological type with high epidemic potential.

  1. Environmental hazard of pesticides applied in the border region between Platinum and Amazon Basins at the turn to century XXI

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    Arno Rieder

    2012-03-01

    Full Text Available Objective: To reveal the environmental risk of pesticide prescribed in a border region between the Amazon and Platinum Basins, at the turn of the 21st century. Methods: The study used data of agronomic prescriptions for pesticides issued in the biennium of 1999-2000 in 24 cities located in a border region between the Amazon and Platinum Basins, Mato Grosso, Brazil. Results: The most widely used pesticides in the study region are class II (very dangerous and III (dangerous in number of prescriptions (N = 2,828, 86.8% andquantity prescribed (N = 344,765, 90.4%. Among class III pesticides, a strong inversion was observed in the number of prescriptions (N = 1,274; 39.1% and quantity prescribed (N = 237,319; 62.2%, indicating a lower number of prescriptions, but with higher amountprescribed. The proportion of prescriptions for products amid the various classes of Potential of Environmental Dangers (PPA ranking model, apllied in Brazil changed over the two years (c2=20,814; DF=3; p < 0,01. The 10 most prescribed products (11 activecompounds were: glyphosate, 2,4-D, sulfluramid, chlorimuron ethyl, fipronil, diuron, paraquat, methamidophos, carbofuran, chlorpyrifos and lambda-cyhalothrin, and seven of them were ranked as PPA class I or II. Conclusions: The ratio between the number of pesticide prescriptions and the quantities prescribed among the various classes of PPA showed alteration over crop years. The most reported products in this border region were classified as the most dangerous ones, with diverse mechanisms of action and potential risksto living organisms. This suggests the need to define specific policies and carefully designed strategies to prevent environmental disaster in this region.

  2. Carbon monoxide and related trace gases and aerosols over the Amazon Basin during the wet and dry seasons

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    M. O. Andreae

    2012-07-01

    Full Text Available We present the results of airborne measurements of carbon monoxide (CO and aerosol particle number concentration (CN made during the Balanço Atmosférico Regional de Carbono na Amazônia (BARCA program. The primary goal of BARCA is to address the question of basin-scale sources and sinks of CO2 and other atmospheric carbon species, a central issue of the Large-scale Biosphere-Atmosphere (LBA program. The experiment consisted of two aircraft campaigns during November–December 2008 (BARCA-A and May–June 2009 (BARCA-B, which covered the altitude range from the surface up to about 4500 m, and spanned most of the Amazon Basin.

    Based on meteorological analysis and measurements of the tracer, SF6, we found that airmasses over the Amazon Basin during the late dry season (BARCA-A, November 2008 originated predominantly from the Southern Hemisphere, while during the late wet season (BARCA-B, May 2009 low-level airmasses were dominated by northern-hemispheric inflow and mid-tropospheric airmasses were of mixed origin. In BARCA-A we found strong influence of biomass burning emissions on the composition of the atmosphere over much of the Amazon Basin, with CO enhancements up to 300 ppb and CN concentrations approaching 10 000 cm−3; the highest values were in the southern part of the Basin at altitudes of 1–3 km. The ΔCN/ΔCO ratios were diagnostic for biomass burning emissions, and were lower in aged than in fresh smoke. Fresh emissions indicated CO/CO2 and CN/CO emission ratios in good agreement with previous work, but our results also highlight the need to consider the residual smoldering combustion that takes place after the active flaming phase of deforestation fires.

    During the late wet season, in contrast, there was little evidence for a significant presence of biomass smoke. Low CN concentrations (300–500 cm−3 prevailed basinwide, and CO mixing ratios were enhanced

  3. Impacts of climate variability and extreme events on the terrestrial carbon cycle of the Amazon basin

    Science.gov (United States)

    Harper, A. B.; Cox, P.; Wiltshire, A.; Friedlingstein, P.; Jones, C. D.; Mercado, L.; Groenendijk, M.; Sitch, S.

    2013-12-01

    Several climate models predict reduced dry season rainfall in the Amazon region as a consequence of climate change. Drier dry seasons could have profound negative consequences for the forest, since soil moisture levels are already near their lower limit during this time of the year. Two recent dry season droughts (during 2005 and 2010) could provide insight into the future of the region. These droughts were associated with sea surface temperature anomalies in the tropical North Atlantic Ocean. Additionally, El Niño-related temperature anomalies in the tropical Pacific Ocean can lead to drought in the northern Amazon. In this work, we use a land surface model with updated physiology and vegetation dynamics to investigate responses of the Amazon terrestrial carbon cycle to recent droughts. JULES (the Joint UK Land-Environment Simulator) is the land surface model in the Hadley Centre Earth System Model. Several recent model developments have improved its ability to replicate seasonal cycles of land fluxes in tropical forests, such as new plant functional types, plant trait-based physiological parameters, and a multi-layer canopy with two-stream radiation and sunfleck penetration. In addition, several non-standard updates to JULES can improve the model in this region: including a representation of deeper soils and efficient roots, and parameter optimization. The soil and rooting adjustments are based on previous work with the Simple Biosphere (SiB3) model, which has been tested extensively in the Amazon. SiB3 can include a climate-derived, spatially varying predictor of forest drought resistance, which enabled it to simulate forest response to persistent soil moisture deficits during two rainfall exclusion projects in the Amazon. We ran JULES from pre-industrial to present day, forced with observed climate, atmospheric CO2, and land use. A mixture of satellite- and ground-based observations was used to validate JULES seasonal cycles of surface fluxes, phenology

  4. Epidemiology of Spotted Fever Group and Typhus Group Rickettsial Infection in the Amazon Basin of Peru

    Science.gov (United States)

    2010-01-01

    AC, Dfaz DE, L6pez TJ, 2007. Rickettsiosis, emerging dis- ease in Loreto. Rev Peru Med Exp Salud Publica 24: 99-100. 24. Morrison AC, Forshey BM...evidence of spotted fever group-related Rickettsia transmission in the Peruvian Amazon jungle. Rev Peru Med Exp Sa/ud Publica 23: 284-287. 23. Ramal...from an endemic area for Brazilian spotted fever in the State of Sao Paulo, Brazil. Cad Saude Publica 24: 247-252. 37. Horta MC, Labruna MB

  5. Vulnerability associated with "symptoms similar to those of mercury poisoning" in communities from Xingu River, Amazon basin.

    Science.gov (United States)

    Da Silva-Junior, Flávio Mnaoel Rodrigues; Oleinski, Ritta M; Azevedo, Antonia E S; Monroe, Kátia C M C; Dos Santos, Marina; Da Silveira, Tatiane Britto; De Oliveira, Adrianne Maria Netto; Soares, Maria Cristina Flores; Pereira, Tatiana Da Silva

    2017-06-03

    The Brazilian Amazon is known to be a region with high levels of mercury (Hg) in the environment and studies point to an association between high levels of natural mercury in the mother rock and the vast number of clandestine gold mines. Other studies already report the contamination of fish in this region, as well as high levels of Hg in biological material from environmentally exposed populations. On the other hand, this is one of the least developed regions of the planet and it is necessary to understand the vulnerability factors in these populations that may be intoxicated by this element. The purpose of the present study was to investigate the vulnerability factors in communities from Xingu River-Amazon basin probably exposed to Hg. A cross-selection study in two cities localized in Xingu River was conducted, and the sample contained was 268 individuals. sociodemographic questions, lifestyle, diet habits and health conditions were collated. The majority of the sample was female, between 30 and 59 years old, had less than 3 years of educational level and lived in the local of study more than 240 months. There was regular fish consumption (95.9%), principally carnivorous species (80.5%). The visual problem has a highest prevalence (43.3%) between the health problems and about the symptoms of Hg intoxication, memory loss (42.9%), weakness (35.1%), fatigue (34.3%), mood changes (28.7%) and difficulties in concentration (27.2%) was most reported. The female sex, age over 60, educational level below 3 years of study, did not had flush toilet, smoke and least one chronic non-communicable disease represent higher probability to had symptoms of Hg intoxication. Lack of access to health services, low education level and income evidence the susceptibility of this community to diseases and injuries. The vulnerable groups identified in this study should be a priority in public health and environmental health policies.

  6. Methane and carbon dioxide production in soils flooded by the Belo Monte hydropower reservoir in the Amazon Basin, Brazil

    Science.gov (United States)

    Sawakuchi, H. O.; Bertassoli, D. J., Jr.; Silveira, A. M.; Bozi, B. S.; de Jesus, J. S.; Sawakuchi, A. O.; Ward, N. D.; Bastviken, D.; Krusche, A. V.; Richey, J. E.

    2016-12-01

    The Xingu River, one of the major tributary of the Amazon River, was recently impounded by the Belo Monte dam, a massive and controversial hydropower plant that will become the third biggest power station in generating capacity of the world. Given the limited data associated with greenhouse gas emissions from reservoirs in the Amazon basin, the impacts of hydroelectric expansion in this region to the global carbon budget remains unclear. Here, we used a bottom-up assessment to quantify a fraction of the possible emissions associated with the Belo Monte reservoir. Eighteen soil samples were collected before the impoundment from seven different locations and depths in areas that were going to be permanently flooded by the reservoir (forests and pasturelands). Soil samples were split in triplicates and incubated in anoxic conditions during two phases totaling 160 days of anoxic incubation in order to quantify the potential methane and carbon dioxide production through time. Our results showed that pasturelands soil presented higher potential production of both gases in relation to the soils from forested areas, reaching up to 0.072 mg CH4 g-¹d-1 and 0.078 mg CO2 g-¹d-1 during the first period of 65 days in the first phase of incubations. Significant differences in production were also noted through soil depth and time. In several areas, the first 15 cm of soil generated 99% of the methane volume that was being produced in the 60 cm sampled profile. The first 65 days of the second phase of incubations showed production that was 35% (CH4) and 44% (CO2) lower than the same period in the first stage. Extrapolations towards the total flooded area demonstrates that 27.3-43.3 ton CH4 d-1 may be generated from flooded soils in the Belo Monte reservoir during only the first several months of flooding, maintaining significant production rates during upcoming months as long as favorable conditions are maintained.

  7. U-Pbdating on detrital zircon and Nd and Hf isotopes related to the provenance of siliciclastic rocks of the Amazon Basin: Implications for the origin of Proto-Amazonas River

    Science.gov (United States)

    Dantas, Elton Luiz; Silva Souza, Valmir; Nogueira, Afonso C. R.; Ventura Santos, Roberto; Poitrasson, Franck; Vieira Cruz, Lucieth; Mendes Conceição, Anderson

    2014-05-01

    provenance dominated by Mesoproterozoic sources (1.0, 1.2 Ga) and subordinate Neoproterozoic(550-800 Ma) and Archean derivation (2.67 Ga). On the other hand, detrital zircon and Hf and NdTDM model ages for the Cretaceous Alter do Chão Formation yielded a unique Paleoproterozoicages between 2.0 and 2.3 Ga that can be correlated to sources derived from Maroni-Itacaiúnas and Central Amazonian basement provinces. The contribution of Precambrian and Paleozoic rocks exposed during the installationof the Amazonas drainage were probably significant .Such a large contribution from Neoproterozoic and Mesoproterozoic sources are not common in the proximal Amazon Craton basement .This new proposal open new perspectives to understand better the initial history of Amazon River with indication of the probable source areas during Late Cenozoic. Campbell Jr.; Frailey,C.D.; Romero-Pittman, G. 2006. The Pan-Amazonian UcayliPeneplain, late Neogenesedimentacion in Amazonia, and the Birth on the Modern Amazon River system.Palaeogeography,Palaeoclimatology, Palaeoecology. 239 (2006) 166-219 Figueiredo, J.,Hoorn, C., Van der Vem, P., Soares, E. 2009. Late Miocene onset of the Amazon River and the Amazon deep-sea fan: Evidence from the Fozdo Amazonas Basin. Geology, 37(7):619-622. Hoorn,C.; Guerrero, J.; Sarmiento, G. 1995. Andean tectonics as a cause for changing drainage patterns in Miocene Northern South America. Geology, v.23, p-237-240. Nogueira, A.C.R.; Silveira, R.R.; Guimarães, J.T.F. 2013. Neogene-Quaternary sedimentary and paleovegetation history of the eastern Solimões Basin, central Amazon region.Journal of South American Earth Sciences , v. 46, p. 89-99, 2013. Potter, P.E. 1997. The Mesozoic and Cenozoic paleodrainage of South America: a natural history. Journal of South American Earth Science.v.10. p.331-344 Wesselingh, F. P., et al., 2002. Lake-Pebas: a palaeocological reconstruction of a Miocene long-lived lake comples in Western Amazônia. Cainozoic Research 1 (1-2), 35-81.

  8. An outline of neotectonic structures and morphotectonics of the western and central Pannonian basin.

    NARCIS (Netherlands)

    Fodor, L.; Bada, G.; Csillag, G.; Horvath, E.; Ruszkiczay-Rudiger, Z.; Klara, P.; Sikhegyi, F.; Timár, G.; Cloetingh, S.A.P.L.; Horvath, F.

    2005-01-01

    Neotectonic deformation in the western and central part of the Pannonian Basin was investigated by means of surface and subsurface structural analyses, and geomorphologic observations. The applied methodology includes the study of outcrops, industrial seismic profiles, digital elevation models,

  9. LBA Regional Boundary for the Amazon and Tocantins River Basins, 5-min

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is an expanded version of the Costa et al. (2000) data set and consists of a single grid with values of 1 for cells within the basins and 0 for cells...

  10. Modeling surface water dynamics in the Amazon Basin using MOSART-Inundation v1.0: impacts of geomorphological parameters and river flow representation

    Science.gov (United States)

    Luo, Xiangyu; Li, Hong-Yi; Leung, L. Ruby; Tesfa, Teklu K.; Getirana, Augusto; Papa, Fabrice; Hess, Laura L.

    2017-03-01

    In the Amazon Basin, floodplain inundation is a key component of surface water dynamics and plays an important role in water, energy and carbon cycles. The Model for Scale Adaptive River Transport (MOSART) was extended with a macroscale inundation scheme for representing floodplain inundation. The extended model, named MOSART-Inundation, was used to simulate surface hydrology of the entire Amazon Basin. Previous hydrologic modeling studies in the Amazon Basin identified and addressed a few challenges in simulating surface hydrology of this basin, including uncertainties of floodplain topography and channel geometry, and the representation of river flow in reaches with mild slopes. This study further addressed four aspects of these challenges. First, the spatial variability of vegetation-caused biases embedded in the HydroSHEDS digital elevation model (DEM) data was explicitly addressed. A vegetation height map of about 1 km resolution and a land cover dataset of about 90 m resolution were used in a DEM correction procedure that resulted in an average elevation reduction of 13.2 m for the entire basin and led to evident changes in the floodplain topography. Second, basin-wide empirical formulae for channel cross-sectional dimensions were refined for various subregions to improve the representation of spatial variability in channel geometry. Third, the channel Manning roughness coefficient was allowed to vary with the channel depth, as the effect of riverbed resistance on river flow generally declines with increasing river size. Lastly, backwater effects were accounted for to better represent river flow in mild-slope reaches. The model was evaluated against in situ streamflow records and remotely sensed Envisat altimetry data and Global Inundation Extent from Multi-Satellites (GIEMS) inundation data. In a sensitivity study, seven simulations were compared to evaluate the impacts of the five modeling aspects addressed in this study. The comparisons showed that

  11. Spatial variability of soil carbon stock in the Urucu river basin, Central Amazon-Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Ceddia, Marcos Bacis, E-mail: marcosceddia@gmail.com [Department of Soil, Institute of Agronomy, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, RJ 23890-000 (Brazil); Villela, André Luis Oliveira [Colégio Técnico da UFRRJ, RJ, Seropédica 23890-000 (Brazil); Pinheiro, Érika Flávia Machado [Department of Soil, Institute of Agronomy, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, RJ 23890-000 (Brazil); Wendroth, Ole [Department of Plant & Soil Sciences, University of Kentucky, College of Agriculture, Lexington, KY (United States)

    2015-09-01

    The Amazon Forest plays a major role in C sequestration and release. However, few regional estimates of soil organic carbon (SOC) stock in this ecoregion exist. One of the barriers to improve SOC estimates is the lack of recent soil data at high spatial resolution, which hampers the application of new methods for mapping SOC stock. The aims of this work were: (i) to quantify SOC stock under undisturbed vegetation for the 0–30 and the 0–100 cm under Amazon Forest; (ii) to correlate the SOC stock with soil mapping units and relief attributes and (iii) to evaluate three geostatistical techniques to generate maps of SOC stock (ordinary, isotopic and heterotopic cokriging). The study site is located in the Central region of Amazon State, Brazil. The soil survey covered the study site that has an area of 80 km{sup 2} and resulted in a 1:10,000 soil map. It consisted of 315 field observations (96 complete soil profiles and 219 boreholes). SOC stock was calculated by summing C stocks by horizon, determined as a product of BD, SOC and the horizon thickness. For each one of the 315 soil observations, relief attributes were derived from a topographic map to understand SOC dynamics. The SOC stocks across 30 and 100 cm soil depth were 3.28 and 7.32 kg C m{sup −2}, respectively, which is, 34 and 16%, lower than other studies. The SOC stock is higher in soils developed in relief forms exhibiting well-drained soils, which are covered by Upland Dense Tropical Rainforest. Only SOC stock in the upper 100 cm exhibited spatial dependence allowing the generation of spatial variability maps based on spatial (co)-regionalization. The CTI was inversely correlated with SOC stock and was the only auxiliary variable feasible to be used in cokriging interpolation. The heterotopic cokriging presented the best performance for mapping SOC stock. - Highlights: • The SOC stocks across 30 and 100 cm depth were 3.28 and 7.32 kg C m{sup −2}, respectively. • SOC stocks were 34 and 16

  12. Anthropogenic carbon dioxide in the South Atlantic western basin

    Science.gov (United States)

    Ríos, Aida F.; Vázquez-Rodríguez, Marcos; Padin, X. A.; Pérez, Fiz F.

    2010-10-01

    The meridional WOCE line A17 was conducted during the austral summer of 1994 parallel to the eastern South American coast, from 55°S to 10°S, where one of the main limbs of the North Atlantic Deep Water (NADW), i.e., the southward-flowing Deep Western Boundary Current (DWBC) is found. Full-depth profiles of pH, total alkalinity and total inorganic carbon were measured and checked with analytical CO 2 certified reference materials (CRMs), providing a high-quality dataset with good internal consistency for the CO 2 system parameters that is well suited for anthropogenic CO 2 (C ANT) estimation. For the first time in the western Atlantic basin the C ANT has been calculated using four independent approaches and results are compared. The methods considered are the CFC-based TTD method and the φC T°, TrOCA and ∆C* carbon system-based back-calculation methods. All four methods have produced C ANT distribution patterns that are in general good agreement: maximum concentrations of C ANT (50-60 μmol kg - 1 ) are predicted for the upper warm South Atlantic central waters from the tropical gyres, while the minima (~ 5 μmol kg - 1 ) are located in the old northward-flowing branch of Circumpolar Deep Water. There are, however, some discrepancies detected. The TrOCA method yields the highest overall [C ANT] values, even over the theoretical limit of C ANT saturation for 1994 in the upper layers. The ∆C* approach consistently yielded negative estimates of C ANT below 2800 dbar, even after correcting a reported - 8 μmol kg - 1 bias in the alkalinity measurements of the WOCE A17 line. The main overall difference between the four methods corresponds to the relative C ANT maximum associated with the lower limb of NADW: this structure is well identified in the φC T° and TTD methods but seems to disappear in the case of TrOCA and ∆C*. In agreement with other intercomparison studies of C ANT, the specific inventories are significantly higher (~ 45%) than those reported in

  13. Mapping Land Cover Types in Amazon Basin Using 1km JERS-1 Mosaic

    Science.gov (United States)

    Saatchi, Sassan S.; Nelson, Bruce; Podest, Erika; Holt, John

    2000-01-01

    In this paper, the 100 meter JERS-1 Amazon mosaic image was used in a new classifier to generate a I km resolution land cover map. The inputs to the classifier were 1 km resolution mean backscatter and seven first order texture measures derived from the 100 m data by using a 10 x 10 independent sampling window. The classification approach included two interdependent stages: 1) a supervised maximum a posteriori Bayesian approach to classify the mean backscatter image into 5 general land cover categories of forest, savannah, inundated, white sand, and anthropogenic vegetation classes, and 2) a texture measure decision rule approach to further discriminate subcategory classes based on taxonomic information and biomass levels. Fourteen classes were successfully separated at 1 km scale. The results were verified by examining the accuracy of the approach by comparison with the IBGE and the AVHRR 1 km resolution land cover maps.

  14. New dactylogyrids (Monogenea) parasitizing the gills of catfishes (Siluriformes) from the Amazon River basin in Peru.

    Science.gov (United States)

    Mendoza-Franco, Edgar F; Scholz, T

    2009-08-01

    Three dactylogyrid (Monogenea) species are described from the gills of siluriform fishes from the rivers around Iquitos, tributaries of the Amazon River in Peru: Demidospermus centromochli n. sp. from Centromochlus heckelii (de Filippi) (Auchenipteridae) and Demidospermus macropteri n. sp. and Ameloblastella unapi n. sp. from Calophysus macropterus (Lichtenstein) (Pimelodidae). The new species of Demidospermus differ from their congeners in having 2 different hook shapes. Ameloblastella unapi n. sp. differs from the other 3 species of the genus in having anchors with an elongate, straight shaft and a short point that forms a 90 degrees angle, a coiled (counterclockwise) male copulatory organ with 13-14 rings, and a coiled vaginal tube. Based on the present study, Pseudovancleaveus Franca, Issac, Pavanelli, and Takemoto, 2003, is regarded as a junior subjective synonym of Ameloblastella Kritsky, Mendoza-Franco, and Scholz, 2000. The finding of Demidospermus and Ameloblastella spp. on these siluriforms extends our host and geographic knowledge of species of these monogenean genera to Peru.

  15. Land-Use Change, Soil Process and Trace Gas Fluxes in the Brazilian Amazon Basin

    Science.gov (United States)

    Melillo, Jerry M.; Steudler, Paul A.

    1997-01-01

    We measured changes in key soil processes and the fluxes of CO2, CH4 and N2O associated with the conversion of tropical rainforest to pasture in Rondonia, a state in the southwest Amazon that has experienced rapid deforestation, primarily for cattle ranching, since the late 1970s. These measurements provide a comprehensive quantitative picture of the nature of surface soil element stocks, C and nutrient dynamics, and trace gas fluxes between soils and the atmosphere during the entire sequence of land-use change from the initial cutting and burning of native forest, through planting and establishment of pasture grass and ending with very old continuously-pastured land. All of our work is done in cooperation with Brazilian scientists at the Centro de Energia Nuclear na Agricultura (CENA) through an extant official bi-lateral agreement between the Marine Biological Laboratory and the University of Sao Paulo, CENA's parent institution.

  16. Properties of refractory BC containing particles during the ACRIDICON-CHUVA aircraft campaign in the Amazon basin

    Science.gov (United States)

    Holanda, Bruna; Pöhlker, Mira; Klimach, Thomas; Saturno, Jorge; Ditas, Florian; Ditas, Jeannine; Ma, Nan; Zhang, Yuxuan; Cheng, Yafang; Wendisch, Manfred; Machado, Luiz; Barbosa, Henrique; Pöhlker, Christopher; Artaxo, Paulo; Pöschl, Ulrich; Andreae, Meinrat

    2017-04-01

    Black carbon (BC) particles are emitted directly into the atmosphere by processes of incomplete combustion and therefore can be used as a tracer of atmospheric pollution. BC is considered one of the drivers of global warming due to its efficient absorption of solar and infra-red radiation (Bond et al., 2013). Depending on abundance and size, aerosols can also modify the characteristics of clouds and enhance or suppress precipitation (Pöschl et al., 2010). The BC particles can gain surface coatings by condensation of low and semi-volatile compounds, coagulation, and cloud processing. The inclusion of a non-absorbing coating influences the way that BC particles act as cloud nuclei and may increase their absorption through the lensing effect (Fuller et al., 1999). These aging processes change significantly the optical, chemical and physical properties of the particles, as well as their atmospheric lifetime, making BC a source of large uncertainties in current atmospheric models. Taking into account the complex dynamics of BC particles in the atmosphere, we are analyzing data from the ACRIDICON-CHUVA aircraft campaign, which took place in the Amazon basin, Brazil, during the dry season of 2014 (Wendisch et al., 2016). A detailed characterization of BC particles was done using the Single Particle Soot Photometer (SP2) instrument, which directly measures the mass of individual refractory BC particles (rBC). Additionally, the SP2 provides information about the size distribution of rBC cores and their associated coatings. These properties were measured covering a wide geographic area with different pollution conditions and at several levels of the atmosphere at high time resolution. The rBC concentrations change significantly with altitude and with the source of pollution, being a few nanograms per cubic meter for altitudes higher that 5 km. In the surroundings of Manaus city, the mean BC concentration was 0.7 μg/m3, with core sizes peaking at 180 nm. The highest BC mass

  17. An outbreak of fulminant hepatitis delta in the Waorani, an indigenous people of the Amazon basin of Ecuador.

    Science.gov (United States)

    Manock, S R; Kelley, P M; Hyams, K C; Douce, R; Smalligan, R D; Watts, D M; Sharp, T W; Casey, J L; Gerin, J L; Engle, R; Alava-Alprecht, A; Martínez, C M; Bravo, N B; Guevara, A G; Russell, K L; Mendoza, W; Vimos, C

    2000-01-01

    An outbreak of delta hepatitis occurred during 1998 among the Waorani of the Amazon basin of Ecuador. Among 58 people identified with jaundice, 79% lived in four of 22 Waorani communities. Serum hepatitis B surface antigen (HBsAg) was found in the sera of 54% of the jaundiced persons, and 14% of asymptomatic persons. Ninety-five percent of 105 asymptomatic Waorani had hepatitis B core (HBc) IgG antibody, versus 98% of 51 with jaundice. These data confirm that hepatitis B virus (HBV) infection is highly endemic among the Waorani. Sixteen of 23 (70%) HBsAg carriers identified at the onset of the epidemic had serologic markers for hepatitis D virus (HDV) infection. All 16 were jaundiced, where as only two of seven (29%) with negative HDV serology were jaundiced (P = .0006). The delta cases clustered in families, 69% were children and most involved superinfection of people chronically infected with HBV. The data suggest that HDV spread rapidly by a horizontal mode of transmission other than by the sexual route.

  18. Three new species of the armored catfish genus Loricaria (Siluriformes: Loricariidae from river channels of the Amazon basin

    Directory of Open Access Journals (Sweden)

    Matthew R. Thomas

    Full Text Available Three new species of Loricaria are described from large white- and black-water river channels of the Amazon basin of Brazil, the upper rio Negro drainage of southern Venezuela, and clear waters of the lower rio Tocantins. Loricaria spinulifera and L. pumila differ from other species of Loricaria by having unique patterns of abdominal plate development and hypertrophied odontodes forming conspicuous crests on dorsal surfaces of the head and predorsal plates. Both are small species of Loricaria, reaching sexual maturity at less than 120 mm SL, and exhibiting sexually dimorphic characters consistent with members of the L. cataphracta complex. Loricaria spinulifera differs from L. pumila in having a unique arrangement of buccal papillae and large thorn-like odontodes on the dorsum of the head. Loricaria pumila is the smallest known Loricaria, reaching sexual maturity at less than 80 mm SL. Loricaria lundbergi differs from other Loricaria by having a unique abdominal plate pattern, broad head, and small basicaudal plate. Loricaria lundbergi is sympatric with L. spinulifera in the lower rio Negro drainage, but is also known from the rio Baria system of the Casiquiare drainage. Loricaria pumila occurs in the lower rio Amazonas and lower rio Tocantins. All three new species exhibit varying degrees of reduction in eye size and pigmentation seen in other fishes inhabiting deep river channels of South America.

  19. Adolescent pregnancies in the Amazon Basin of Ecuador: a rights and gender approach to adolescents’ sexual and reproductive health

    Directory of Open Access Journals (Sweden)

    Isabel Goicolea

    2010-06-01

    Full Text Available In the Andean region of Latin America over one million adolescent girls get pregnant every year. Adolescent pregnancy (AP has been associated with adverse health and social outcomes, but it has also been favorably viewed as a pathway to adulthood. AP can also be conceptualized as a marker of inequity, since it disproportionately affects girls from the poorest households and those who have not been able to attend school. Using results from a study carried out in the Amazon Basin of Ecuador, this paper explores APs and adolescents’ sexual and reproductive health from a rights and gender approach. The paper points out the main features of a rights and gender approach, and how it can be applied to explore Aps. Afterward it describes the methodologies (quantitative and qualitative and main results of the study, framing the findings within the rights and gender approach. Finally, some implications that could be generalizable to global reserach on APs are highlighted. The application of the rights and gender framework to explore APs contributes to a more integral view of the issue. The rights and gender framework stresses the importance of the interaction between rights-holders and duty-bearers on the realization of sexual and reproductive rights, and acknowledges the importance of gender–power relations on sexual and reproductive decisions. A rights and gender approach could lead to more integral and constructive interventions, and it could also be useful when exploring other sexual and reproductive health matters.

  20. Oil development and health in the Amazon basin of Ecuador: the popular epidemiology process.

    Science.gov (United States)

    San Sebastián, Miguel; Hurtig, Anna Karin

    2005-02-01

    Recent decades have witnessed an increasing corporate access to and control over natural resources resulting in environmental degradation, inequalities and ill health. Since 1972, oil companies have extracted more than two billion barrels of crude oil from the Ecuadorian Amazon. During this process, millions of gallons of untreated toxic wastes, gas and oil have been released into the environment. Indigenous federations, peasant's movements and environmental groups have claimed that contamination has caused widespread damage to both people and the environment. This article tells the story of how the relationship between local organisations and research institutions developed around an epidemiological study constructed to address communities' concerns. Local organisations set the agenda of the research: they were involved in the hypothesis formulation, consulted in each step during the study and responsible of the dissemination of the findings. This process is known as popular epidemiology. Practical and personal issues and dilemmas faced during the research process are discussed with emphasis on the communication and dissemination of the findings. The article concludes the need of alliances between communities and researchers in order to protect health and environment. Popular epidemiology is an essential approach for public health researchers to reaffirm their roots in improving public health as a primary value.

  1. Molecular characterization of the hepatitis B virus in autochthonous and endogenous populations in the Western Brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Ádila Liliane Barros Dias

    2012-02-01

    Full Text Available INTRODUCTION: Hepatitis B virus (HBV infection is a serious public health issue worldwide. Hepatitis B virus is classified into eight genotypes, varying from A to H, with distinct geographical distributions. In Brazil, the most frequent genotypes are A, D, and F. METHODS: This study aimed to characterize the HBV genotypes in cases of hepatitis B virus and hepatitis D virus (HDV co-infections in an endemic area in the Western Brazilian Amazon. We analyzed 86 serum samples reactive for HBsAg from indigenous and non-indigenous populations obtained from previous serological surveys. RESULTS: Of the 86 reactive serum samples, 39 were found to be HBV-DNA-positive by semi-nested PCR. The genotypes were established by sequencing the amplified S gene region. We obtained 20 sequences classified into three genotypes: A, D, and F. Genotype A was the most frequent (60%, followed by D (35% and F (5%. CONCLUSIONS: The distribution of the HBV genotypes reflected the pattern of historical occupation of the region.

  2. Croton maasii (Euphorbiaceae), a new species from the western Amazon region

    NARCIS (Netherlands)

    Riina, R.; Berry, P.E.

    2011-01-01

    Croton maasii, a new species from South America, is described and illustrated. The species is only known from terra firme forests of the extreme western Amazonian region, in W Brazil and adjacent E Peru. Croton maasii resembles C. pachypodus, a more abundant and widely distributed species in the

  3. Hydrological Controls of Riverine Ecosystems of the Napo River (Amazon Basin): Implications for the Management and Conservation of Biodiversity

    Science.gov (United States)

    Celi, J. E.; Hamilton, S. K.

    2013-12-01

    Scientific understanding of neotropical floodplains comes mainly from work on large rivers with predictable seasonal flooding regimes. Less studied rivers and floodplains on the Andean-Amazon interface are distinct in their hydrology, with more erratic flow regimes, and thus ecological roles of floodplain inundation differ in those ecosystems. Multiple and unpredictable flooding events control inundation of floodplains, with important implications for fish and wildlife, plant communities, and human activities. Wetlands along the river corridor exist across a continuum from strong river control to influence only by local waters, with the latter often lying on floodplain paleoterraces. The goal of this study was to understand the hydrological interactions and habitat diversity of the Napo River, a major Amazon tributary that originates in the Andes and drains exceptionally biodiverse Andean foreland plains. This river system is envisioned by developers as an industrial waterway that would require hydrological alterations and affect floodplain ecosystems. Water level regimes of the Napo River and its associated environments were assessed using networks of data loggers that recorded time under water across transects extending inland from the river across more than 100 sites and for up to 5 years. These networks also included rising stage samplers that collected flood water samples for determination of their origin (i.e., Andean rivers vs. local waters) based on hydrochemical composition. In addition, this work entails a classification of aquatic environments of the Napo Basin using an object-oriented remote sensing approach to simultaneously analyze optical and radar satellite imagery and digital elevation models to better assess the extent and diversity of flooded environments. We found out a continuum of hydrological regimes and aquatic habitats along the Napo River floodplains that are linked to the river hydrology in different degrees. Overall, environments that

  4. The Impacts of the Luni-Solar and Arctic Oscillations on the Interdecadal Rainfall and Current Drought in the Amazon Basin

    Science.gov (United States)

    Avissar, R.; Ramos da Silva, R.

    2006-05-01

    Using a combination of rainfall observations in the Amazon Basin, Atlantic Sea-Surface Temperatures (SST), and the time series of the Luni-Solar Oscillation (LSO), we demonstrate that the interdecadal rainfall variability in the basin is correlated with the Arctic Oscillation (AO) and the LSO. The periodicity is about 18 years, which follows the LSO evolution in the second half of the 20th century. A recent phase lag identified between the rainfall variability and the AO is consistent with the predicted weakening of the thermohaline circulation in the Atlantic. This discovery explains the drought currently experienced in the basin and considerably improves our capability to predict interdecadal rainfall variability in that region.

  5. Impacts of extreme events of drought and flood on local communities of Amazon basin

    Science.gov (United States)

    Borma, L. D.; Roballo, S.; Zauner, M.; Nascimento, V. F.

    2013-05-01

    The analysis of drought events of 1997/98, 2005 and 2010 in terms of discharge anomalies in the Amazon region confirmed previous findings, such as: a) the influence of the El Niño in more than one hydrological year; b) the increase of the influence of the Atlantic Multidecadal Oscillation of 1998, 2005 and 2010 drought events; c) the low levels of discharge observed in the 2010 drought are attributed to the association of discharge anomalies of the northern and southern tributaries of the Amazon river, and d) the 2010 drought lasted around 1 month (August to November) more than the other drought events analized here. The riverine communities located along the river banks of Solimões/Amazonas suit their economic activities to the oscillation of the water level. In general, low water periods favor the access to important sources of food such as fish and livestock, still allowing crop cultivation on fertile agricultural areas of the floodplain. Conversely, periods of drought increases the difficulties of transport and drinking water supply. During the high water, access to the main food supply (described above) are greatly hampered. However, the floods are recognized as an importance process of natural fertilization. Thus, despite the political, social and economic shortcomings, the local community has, since the pre-colonial period, learned to get the best of each season, providing local, regional and national markets with varzea products. During periods of extreme weather, however, the advantages of each season appear to be reduced, and the drawbacks increased. In fact, during flooding extremes, the access to primary sources of food is hampered by a long period of time and families find themselves forced to leave their homes, eventually losing them. Analysis of flow data to the extreme flooding of 2009, indicate a period of about 6 months of positive anomalies discharge (occurring mainly during high water). At the same time, Civil Defense data points to a

  6. Gastrointestinal parasites in captive and free-ranging Cebus albifrons in the Western Amazon, Ecuador

    Directory of Open Access Journals (Sweden)

    Sarah Martin-Solano

    2017-12-01

    Full Text Available Currently, there is a lack of surveys that report the occurrence of gastrointestinal parasites in the white-headed capuchin monkey (Cebus albifrons. We therefore assessed the presence and richness (= number of different parasite genera of parasites in C. albifrons in wildlife refuges (n = 11 and in a free-ranging group near a human village (n = 15 in the Ecuadorian Amazon. In the 78 samples collected (median of 3 samples per animal, we identified a total of 6 genera of gastrointestinal parasites, representing protozoa, nematodes, acanthocephalans and cestodes. We observed a high prevalence (84% across the 26 individuals, with the most prevalent parasite being Strongyloides sp. (76.9%, followed by Hymenolepis sp. (38.5% and Prosthenorchis elegans (11.5%. We found Entamoeba histolytica/dispar/moskovskii/nuttalli and Capillaria sp. in only a minority of the animals (3.8%. In addition, we observed unidentified strongyles in approximately one-third of the animals (34.6%. We found a total of 6 parasite genera for the adult age group, which showed higher parasite richness than the subadult age group (5 and the juvenile age group (3. Faecal egg/cyst counts were not significantly different between captive and free-ranging individuals or between sexes or age groups. The free-ranging group had a higher prevalence than the captive group; however, this difference was not significant. The only genus common to captive and free-ranging individuals was Strongyloides sp. The high prevalence of gastrointestinal parasites and the presence of Strongyloides in both populations support results from previous studies in Cebus species. This high prevalence could be related to the high degree of humidity in the region. For the free-ranging group, additional studies are required to gain insights into the differences in parasite prevalence and intensity between age and sex groups. Additionally, our study demonstrated that a serial sampling of each individual increases

  7. Variability of aerosol optical properties in the Western Mediterranean Basin

    Directory of Open Access Journals (Sweden)

    M. Pandolfi

    2011-08-01

    Full Text Available Aerosol light scattering, absorption and particulate matter (PM concentrations were measured at Montseny, a regional background site in the Western Mediterranean Basin (WMB which is part of the European Supersite for Atmospheric Aerosol Research (EUSAAR. Off line analyses of 24 h PM filters collected with Hi-Vol instruments were performed for the determination of the main chemical components of PM. Mean scattering and hemispheric backscattering coefficients (@ 635 nm were 26.6±23.2 Mm−1 and 4.3±2.7 Mm−1, respectively and the mean aerosol absorption coefficient (@ 637 nm was 2.8±2.2 Mm−1. Mean values of Single Scattering Albedo (SSA and Ångström exponent (å (calculated from 450 nm to 635 nm at MSY were 0.90±0.05 and 1.3±0.5 respectively. A clear relationship was observed between the PM1/PM10 and PM2.5/PM10 ratios as a function of the calculated Ångström exponents. Mass scattering cross sections (MSC for fine mass and sulfate at 635 nm were 2.8±0.5 m2 g−1 and 11.8±2.2 m2 g−1, respectively, while the mean aerosol absorption cross section (MAC was 10.4±2.0 m2 g−1. The variability in aerosol optical properties in the WMB were largely explained by the origin and ageing of air masses over the measurement site. The MAC values appear dependent of particles aging: similar to the expected absorption cross-section for fresh emissions under Atlantic Advection episodes and higher under aerosol pollution episodes. The analysis of the Ångström exponent as a function of the origin the air masses revealed that polluted winter anticyclonic conditions and summer recirculation scenarios typical of the WMB led to an increase of fine particles in the atmosphere (å = 1.5±0.1 while the aerosol optical properties under Atlantic Advection episodes and Saharan dust outbreaks were clearly

  8. Mapping Aboveground Biomass in the Amazon Basin: Exploring Sensors, Scales, and Strategies for Optimal Data Linkage

    Science.gov (United States)

    Walker, W. S.; Baccini, A.

    2013-05-01

    Information on the distribution and density of carbon in tropical forests is critical to decision-making on a host of globally significant issues ranging from climate stabilization and biodiversity conservation to poverty reduction and human health. Encouraged by recent progress at both the international and jurisdictional levels on the design of incentive-based policy mechanisms to compensate tropical nations for maintaining their forests intact, governments throughout the tropics are moving with urgency to implement robust national and sub-national forest monitoring systems for operationally tracking and reporting on changes in forest cover and associated carbon stocks. Monitoring systems will be required to produce results that are accurate, consistent, complete, transparent, and comparable at sub-national to pantropical scales, and satellite-based remote sensing supported by field observations is widely-accepted as the most objective and cost-effective solution. The effectiveness of any system for large-area forest monitoring will necessarily depend on the capacity of current and near-future Earth observation satellites to provide information that meets the requirements of developing monitoring protocols. However, important questions remain regarding the role that spatially explicit maps of aboveground biomass and carbon can play in IPCC-compliant forest monitoring systems, with the majority of these questions stemming from doubts about the inherit sensitivity of satellite data to aboveground forest biomass, confusion about the relationship between accuracy and resolution, and a general lack of guidance on optimal strategies for linking field reference and remote sensing data sources. Here we demonstrate the ability of a state-of-the-art satellite radar sensor, the Japanese ALOS/PALSAR, and a venerable optical platform, Landsat 5, to support large-area mapping of aboveground tropical woody biomass across a 153,000-km2 region in the southwestern Amazon

  9. Insights from Integrative Systematics Reveal Cryptic Diversity in Pristimantis Frogs (Anura: Craugastoridae from the Upper Amazon Basin.

    Directory of Open Access Journals (Sweden)

    H Mauricio Ortega-Andrade

    Full Text Available Pluralistic approaches to taxonomy facilitate a more complete appraisal of biodiversity, especially the diversification of cryptic species. Although species delimitation has traditionally been based primarily on morphological differences, the integration of new methods allows diverse lines of evidence to solve the problem. Robber frogs (Pristimantis are exemplary, as many of the species show high morphological variation within populations, but few traits that are diagnostic of species. We used a combination of DNA sequences from three mitochondrial genes, morphometric data, and comparisons of ecological niche models (ENMs to infer a phylogenetic hypothesis for the Pristimantis acuminatus complex. Molecular phylogenetic analyses revealed a close relationship between three new species-Pristimantis enigmaticus sp. nov., P. limoncochensis sp. nov. and P. omeviridis sp. nov.-originally confused with Pristimantis acuminatus. In combination with morphometric data and geographic distributions, several morphological characters such as degree of tympanum exposure, skin texture, ulnar/tarsal tubercles and sexual secondary characters (vocal slits and nuptial pads in males were found to be useful for diagnosing species in the complex. Multivariate discriminant analyses provided a successful classification rate for 83-100% of specimens. Discriminant analysis of localities in environmental niche space showed a successful classification rate of 75-98%. Identity tests of ENMs rejected hypotheses of niche equivalency, although not strongly because the high values on niche overlap. Pristimantis acuminatus and P. enigmaticus sp. nov. are distributed along the lowlands of central-southern Ecuador and northern Peru, in contrast with P. limoncochensis sp. nov. and P. omeviridis sp. nov., which are found in northern Ecuador and southern Colombia, up to 1200 m in the upper Amazon Basin. The methods used herein provide an integrated framework for inventorying the greatly

  10. The HIV epidemic in the Amazon Basin is driven by prototypic and recombinant HIV-1 subtypes B and F.

    Science.gov (United States)

    Vicente, A C; Otsuki, K; Silva, N B; Castilho, M C; Barros, F S; Pieniazek, D; Hu, D; Rayfield, M A; Bretas, G; Tanuri, A

    2000-04-01

    This paper describes genetic subtypes of HIV-1 found in blood samples from 31 HIV-1-infected people who visited the Counseling and Testing AIDS Center of Instituto de Medicina Tropical in Manaus, Brazil. Manaus, the main city in Brazil's Amazon Basin, is also the closest urban connection for more than 100,000 Indians living in the rain forests of this region. Although to date there is no evidence of increased incidence of HIV-1 infection among the indigenous population, our understanding of both the prevalence and nature of the epidemic in the region as a whole is limited. From the 31 samples analyzed by C2V3 sequencing, we found almost equal proportions of HIV-1 strains belonging to subtype B (n = 16; 51.6%) and subtype F (n = 15; 48.4%), a finding that differs from results from previous studies conducted in urban areas of southeastern Brazil. We also observed the presence of the GWGR amino-acid sequence in the critical tetra-peptide crown of the env V3 loop in the HIV-1 subtype B samples analyzed. Among these samples, we also found 14 mosaic genomes (45.16%) in which different combinations of subtypes B, C, and F were identified between the p24 gag, pro, and env regions. Our data support the hypothesis that the Amazonian HIV-1 infections linked to the urban epidemic in southeastern Brazil. The genetic diversity and the prevalence of mosaic genomes among the isolates in our study confirm an integral role of recombination in the complex Brazilian epidemic.

  11. Insights from Integrative Systematics Reveal Cryptic Diversity in Pristimantis Frogs (Anura: Craugastoridae) from the Upper Amazon Basin

    Science.gov (United States)

    Ortega-Andrade, H. Mauricio; Rojas-Soto, Octavio R.; Valencia, Jorge H.; Espinosa de los Monteros, Alejandro; Morrone, Juan J.; Ron, Santiago R.; Cannatella, David C.

    2015-01-01

    Pluralistic approaches to taxonomy facilitate a more complete appraisal of biodiversity, especially the diversification of cryptic species. Although species delimitation has traditionally been based primarily on morphological differences, the integration of new methods allows diverse lines of evidence to solve the problem. Robber frogs (Pristimantis) are exemplary, as many of the species show high morphological variation within populations, but few traits that are diagnostic of species. We used a combination of DNA sequences from three mitochondrial genes, morphometric data, and comparisons of ecological niche models (ENMs) to infer a phylogenetic hypothesis for the Pristimantis acuminatus complex. Molecular phylogenetic analyses revealed a close relationship between three new species—Pristimantis enigmaticus sp. nov., P. limoncochensis sp. nov. and P. omeviridis sp. nov.—originally confused with Pristimantis acuminatus. In combination with morphometric data and geographic distributions, several morphological characters such as degree of tympanum exposure, skin texture, ulnar/tarsal tubercles and sexual secondary characters (vocal slits and nuptial pads in males) were found to be useful for diagnosing species in the complex. Multivariate discriminant analyses provided a successful classification rate for 83–100% of specimens. Discriminant analysis of localities in environmental niche space showed a successful classification rate of 75–98%. Identity tests of ENMs rejected hypotheses of niche equivalency, although not strongly because the high values on niche overlap. Pristimantis acuminatus and P. enigmaticus sp. nov. are distributed along the lowlands of central–southern Ecuador and northern Peru, in contrast with P. limoncochensis sp. nov. and P. omeviridis sp. nov., which are found in northern Ecuador and southern Colombia, up to 1200 m in the upper Amazon Basin. The methods used herein provide an integrated framework for inventorying the greatly

  12. Two new species of Pseudancistrus (Siluriformes, Loricariidae from the Amazon basin, northern Brazil

    Directory of Open Access Journals (Sweden)

    Gabriel da Costa e Silva

    2015-02-01

    Full Text Available Two new species of Pseudancistrus, a genus diagnosed by non-evertible cheek plates and hypertrophied odontodes along the snout margin, are described from two drainages of the Brazilian Shield: P. kayabi from the rio Teles Pires (rio Tapajós basin and P. asurini from the rio Xingu. The new species are distinguished from congeners (P. barbatus, P. corantijniensis, P. depressus, P. nigrescens, P. reus, and P. zawadzkii by the coloration pattern. Pseudancistrus kayabi has dark bars on the dorsal and caudal fins which are similar to that of P. reus from the Caroní River, Venezuela. Pseudancistrus asurini is unique among Pseudancistrus in having whitish tips of the dorsal and caudal fins in juveniles to medium-sized adults.

  13. Geothermal systems of the Mono Basin-Long Valley region, eastern California and western Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, C.T.; Flynn, T.; Chapman, R.H.; Trexler, D.T.; Chase, G.R.; Bacon, C.F.; Ghusn, G. Jr.

    1985-01-01

    The region that includes Mono Basin, Long Valley, the Bridgeport-Bodie Hills area, and Aurora, in eastern California and western Nevada was studied to determine the possible causes and interactions of the geothermal anomalies in the Mono Basin-Long Valley region as a whole. A special goal of the study was to locate possible shallow bodies of magma and to determine their influence on the hydrothermal systems in the region. (ACR)

  14. Mercury bioaccumulation patterns in fish from the Iténez river basin, Bolivian Amazon.

    Science.gov (United States)

    Pouilly, Marc; Pérez, Tamara; Rejas, Danny; Guzman, Fabiola; Crespo, Giovanni; Duprey, Jean-Louis; Guimarães, Jean-Remy D

    2012-09-01

    The bioaccumulation mechanism expresses an increment of mercury concentration along the lifetime of each individual. It is generally investigated along the age or size range of organisms from a same population. Water chemistry and trophic position are important factors that may influence the emergence of bioaccumulation patterns. In order to detect the influence of these parameters on fish mercury bioaccumulation patterns, we explored the relations between mercury concentration, size and isotopic trophic position of fish populations of six species (three non piscivorous and three piscivorous) in three rivers of the Iténez basin (Bolivia) with different sediment load in water and anthropogenic impact. Fishes of the Iténez basin showed fairly lower mercury contamination in relation to the regional context. They presented lower total mercury concentrations in unperturbed clear water river (average of 0.051 μg g(-1) for non piscivores; 0.088 μg g(-1) for piscivores), intermediate values (average of 0.05 and 0.104 μg g(-1)) in unperturbed white water river, whereas the highest values (average of 0.062 and 0.194 μg g(-1)) were found in the perturbed clear water river. Piscivore and invertivore species showed significant positive bioaccumulation patterns in the perturbed river and in the unperturbed white water river. No positive pattern was detected in the unperturbed clear water river. Positive patterns could not be attributed to differences in trophic condition and mean fish mercury concentration between populations. Bioaccumulation seems not to be the main factor to explain increased mercury concentrations in fish from the perturbed river. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Aphandra natalia(Arecaceae – a little known source of piassaba fibers from the western Amazon

    Directory of Open Access Journals (Sweden)

    Mette Kronborg

    2014-03-01

    Full Text Available Aphandra natalia(Balslev & Henderson Barfod is a multipurpose palm that is exploited both commercially and for subsistence purposes. Its fibers are important in Peruvian and Ecuadorean broom industries and support many people economically. In Brazil, it is found in the western part of Acre, where it is the main source for a local broom market. Data from fieldwork in Peru (2007 suggests that the variation in gross profit per kilogram of fiber is considerable among the different segments in the broom industry. Harvesters and distributors earn negligible amounts of money whereas manufacturers reap of the major part of the earnings. Fiber extraction appears to be sustainable in Ecuador and in some parts of Peru, whereas in other parts of Peru unsustainable harvest occurs, involving felling of entire palm trees for the harvest of fibers. The same destructive extraction method is used in Brazil, where the palm is becoming rare in its natural distribution area.

  16. basin in obafemi awolowo university, ile-ife, south western

    African Journals Online (AJOL)

    2004-08-28

    Aug 28, 2004 ... Printing Press, Ibadan. 106pp. Ogunkoya, O.O., 1980. Hydrology of 3" order basins in the upper Owena drainage basing of southwestern. Nigeria. Unpublished Ph.D. Thesis, Department of. Geography, University of Ife, lle-Ife, Nigeria. pp. 65-. 72. Oluwatimilehin, J.M., 1990. Scdiment dynamics in some 3".

  17. Reference values of lead in blood and related factors among blood donors in the Western Amazon, Brazil.

    Science.gov (United States)

    Freire, Carmen; Koifman, Rosalina Jorge; Fujimoto, Denys; de Oliveira Souza, Vanessa Cristina; Barbosa, Fernando; Koifman, Sergio

    2014-01-01

    The aim of this study was to (1) determine the reference value of blood lead levels (BLL) in a sample of blood donors of Rio Branco, the capital city of Acre, in the Western Brazilian Amazon, and (2) explore factors influencing lead (Pb) exposure levels. Between 2010 and 2011, blood samples were collected from universal blood donors attending the Central Hemotherapic Unit in Rio Branco with a total number of 1196. Information on characteristics of 1183 donors was obtained through questionnaires. Blood Pb concentrations were determined by inductively coupled plasma-mass spectrometry with detection limit of 0.003 μg/L. Association between BLL and participant characteristics was examined by linear regression analysis. Reference values of BLL were calculated as the upper limit of the 95% confidence interval of the 95th percentile. Reference values of BLL were 109.5 μg/L for men, 70.7 μg/L for women, 88.9 μg/L for younger individuals (18-29 yr), 115.3 μg/L for older ones (≥30 yr), 94.2 μg/L for nonsmokers, and 164.5 μg/L for smokers. Levels of BLL were significantly higher in males, subjects older than 29 yr, non-whites, smokers, regular consumers of manioc flour, and donors practicing any activity related to paints, ceramics, pottery, fishing, or firearms. Subjects with higher education, higher income, vitamin intake use, and drinkers of bottled water displayed lower BLL. In general, BLL in men and women from Rio Branco were higher than those described in other adult populations. Prevention of exposure of this population to local sources of Pb needs to be addressed.

  18. Basin Analysis and Petroleum System Characterisation of Western Bredasdorp Basin, Southern Offshore of South Africa: Insights from a 3d Crust-Scale Basin Model - (Phase 1)

    Science.gov (United States)

    Sonibare, W. A.; Scheck-Wenderoth, M.; Sippel, J.; Mikeš, D.

    2012-04-01

    In recent years, construction of 3D geological models and their subsequent upscaling for reservoir simulation has become an important tool within the oil industry for managing hydrocarbon reservoirs and increasing recovery rate. Incorporating petroleum system elements (i.e. source, reservoir and trap) into these models is a relatively new concept that seems very promising to play/prospect risk assessment and reservoir characterisation alike. However, yet to be fully integrated into this multi-disciplinary modelling approach are the qualitative and quantitative impacts of crust-scale basin dynamics on the observed basin-fill architecture and geometries. The focus of this study i.e. Western Bredasdorp Basin constitutes the extreme western section of the larger Bredasdorp sub-basin, which is the westernmost depocentre of the four southern Africa offshore sub-basins (others being Pletmos, Gamtoos and Algoa). These basins, which appear to be initiated by volcanically influenced continental rifting and break-up related to passive margin evolution (during the Mid-Late Jurassic to latest Valanginian), remain previously unstudied for crust-scale basin margin evolution, and particularly in terms of relating deep crustal processes to depo-system reconstruction and petroleum system evolution. Seismic interpretation of 42 2D seismic-reflection profiles forms the basis for maps of 6 stratigraphic horizons which record the syn-rift to post-rift (i.e. early drift and late drift to present-day seafloor) successions. In addition to this established seismic markers, high quality seismic profiles have shown evidence for a pre-rift sequence (i.e. older than Late Jurassic >130 Ma). The first goal of this study is the construction of a 3D gravity-constrained, crust-scale basin model from integration of seismics, well data and cores. This basin model is constructed using GMS (in-house GFZ Geo-Modelling Software) while testing its consistency with the gravity field is performed using IGMAS

  19. Gravity anomalies and the structure of western Tibet and the southern Tarim Basin

    Science.gov (United States)

    Lyon-Caen, H.; Molnar, P.

    1984-01-01

    Gravity anomalies across the western part of the Tarim Basin and the Kunlun mountain belt show that this area is not in local isostatic equilibrium. These data can be explained if a strong plate underlying the Tarim Basin extends southwestward beneath the belt at least 80 km and supports part of the topography of northwest Tibet. This corroborates Norin's inference that late Tertiary crustal shortening has occurred in this area by southward underthrusting of the Tarim Basin beneath the Kunlun. This study places a lower bound on the amount of underthrusting.

  20. Active transtensional intracontinental basins: Walker Lane in the western Great Basin

    Science.gov (United States)

    Jayko, Angela S.; Bursik, Marcus

    2012-01-01

    The geometry and dimensions of sedimentary basins within the Walker Lane are a result of Plio-Pleistocene transtensive deformation and partial detachment of the Sierra Nevada crustal block from the North American plate. Distinct morpho-tectonic domains lie within this active transtensive zone. The northeast end of the Walker Lane is partly buried by active volcanism of the southern Cascades, and adjacent basins are filled or poorly developed. To the south, the basin sizes are moderate, 25–45km × 15–10 km, with narrow 8-12km wide mountain ranges mainly oriented N-S to NNE. These basins form subparallel arrays in discrete zones trending about 300° and have documented clockwise rotation. This is succeeded to the south by a releasing stepover domain ∼85-100km wide, where the basins are elongated E-W to ENE, small (∼15-30km long, 5-15km wide), and locally occupied by active volcanic centers. The southernmost part of the Walker Lane is structurally integrated, with high to extreme relief. Adjacent basins are elongate, 50-200km long and ∼5 -20km wide. Variations in transtensive basin orientations in the Walker Lane are largely attributable to variations in strain partitioning. Large basins in the Walker Lane have 2-6km displacement across basin bounding faults with up to 3 km of clastic accumulation based on gravity and drill hole data. The sedimentary deposits of the basins may include interbedded volcanic deposits with bimodal basaltic and rhyolitic associations. The basins may include lacustrine deposits that record a wide range of water chemistry from cold fresh water conditions to saline-evaporative

  1. Late Quaternary environmental change in the Bonneville basin, western USA

    Science.gov (United States)

    Madsen, D.B.; Rhode, D.; Grayson, D.K.; Broughton, J.M.; Livingston, S.D.; Hunt, J.; Quade, Jay; Schmitt, D.N.; Shaver, M. W.

    2001-01-01

    Excavation and analyses of small animal remains from stratified raptor deposits spanning the last 11.5 ka, together with collection and analysis of over 60 dated fossil woodrat midden samples spanning the last 50 ka, provide a detailed record of changing climate in the eastern Great Basin during the late Pleistocene and Holocene. Sagebrush steppe dominated the northern Bonneville basin during the Full Glacial, suggesting that conditions were cold and relatively dry, in contrast to the southern basin, which was also cold but moister. Limber pine woodlands dominated ???13-11.5 ka, indicating increased dryness and summer temperatures ???6-7??C cooler than present. This drying trend accelerated after ???11.5 ka causing Lake Bonneville to drop rapidly, eliminating 11 species of fish from the lake. From ???11.5-8.2 ka xerophytic sagebrush and shadscale scrub replaced more mesophilic shrubs in a step-wise fashion. A variety of small mammals and plants indicate the early Holocene was ???3??C cooler and moister than at present, not warmer as suggested by a number of climatic models. The diversity of plants and animals changed dramatically after 8.2 ka as many species disappeared from the record. Some of the upland species returned after ???4 ka and Great Salt Lake became fresh enough at ???3.4 and ???1.2 ka to support populations of Utah chub. ?? 2001 Elsevier Science B.V.

  2. Parametric Reconstruction of Water Vapour Accumulation Modes in the Western and the Eastern Mediterranean Basins

    Science.gov (United States)

    Palau, J. L.; Rovira, F.; Millan, M.

    2009-09-01

    The Mediterranean Sea acts as a source of heat and moisture for the surrounding regions, but not only because it is a closed and warm sea. The Mediterranean Basin is located in the mid-latitudes (i.e., high solar insolation), and it is almost completely surrounded by mountains. Moreover, from a meteorological point of view, the Mediterranean Basin can be regarded as two well-differentiated sub-basins: The Western Mediterranean Basin, where the prevailing synoptic conditions are associated with the Azores High Pressure system; and the Eastern Mediterranean Basin, which is under the influence of the Middle-East monsoon low-pressure system. The combination of all these features enables strong evapotranspiration with lower ventilation conditions (especially on the Western side) than in other geographical areas of the world (e.g., areas under the direct influence of the Atlantic Ocean). As a result, there are different water vapour "accumulation modes” on both sides of the Mediterranean Basin. The determination of the main atmospheric accumulation modes and their seasonal variability on both sides of the Mediterranean Basin is a relevant issue for integrating some of the feedbacks driving climate change, e.g., precipitation regimes, secondary pollutant production, ventilation conditions, etc. This study focuses on the total water vapour accumulation modes found on both sides of the Mediterranean Basin throughout the year. The data used in this study come from the most recent EOS satellite missions. Specifically, this investigation analyses the nine-year time series of water vapour data measured by the MODIS instrument (MODerate Resolution Imaging Spectroradiometer) on board the TERRA (EOS AM-1) satellite. Annual evolution (2000-2008) and seasonality of the total precipitable water column are analysed in both the Western and the Eastern Mediterranean Basins. After carrying out the parametric reconstruction of the water vapour time series, we have obtained their

  3. GIS (Geographic Information Systems) based calculation on hydrocarbon generated volume: Amazon Basin example; O uso de SIG no calculo de hidrocarbonetos gerados: exemplo da Bacia do Amazonas

    Energy Technology Data Exchange (ETDEWEB)

    Pedrinha, Saulo; Simoes, Leonardo; Goncalves, Felix T.T.; Carneiro, Jason T.G. [Petroleum Geoscience Technology Ltda. (PGT), Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The calculation of the volume of hydrocarbons generated from a particular source rock a sedimentary basin provides numerical data that help to better describe the petroleum system, and evaluate its potential. Among the various methodologies developed for calculating the volume of oil there is a proposal by Schmoker (1994), which has the advantage to take into account the occurrence of the source rock area in the basin, and the spatial variations in the main geological parameters. Using the tools of a GIS, through the manipulation of georeferred maps, it is possible to calculate the volume of oil generated in a way that would be virtually impossible by using punctual data, only. Even the discretiation maps in minors areas allows, via attribute table in the GIS, the application of a Monte Carlo simulation, which allows to incorporate all the uncertainties related to the input data in the calculation, obtaining distributions of volumes associated with various parts of the final map being integrated throughout the basin. Isopac and maturation maps (Gonzaga et al., 2000), along with TOC data from Barreirinha formation, Amazon Basin, have been scanned and georeferred and, once in the GIS database, were treated in order to spatially distribute the geological properties of the source rock. Then, such maps were handled in accordance with Schmoker (1994) method, leading to a map of mass and distribution of oil generated in the basin at the regional scale. (author)

  4. Karyotype structure of Hypostomus cf. plecostomus (Linnaeus, 1758) from Tapajós River basin, Southern Amazon: occurrence of sex chromosomes (ZZ/ZW) and their evolutionary implications.

    Science.gov (United States)

    Oliveira, L C; Ribeiro, M O; Dutra, E S; Zawadzki, C H; Portela-Castro, A L B; Martins-Santos, I C

    2015-06-18

    Hypostomus is a group of fish with numerical and struc-tural karyotypic variability. Among them, only six species, three of which belong to the Amazon basin, show a sex chromosome. In this study, we present the karyotype structure of Hypostomus cf. plecos-tomus from the Teles Pires river basin in the municipality of Alta Flo-resta, MT. The species has 2n = 68 and the karyotype formula 14m+ 24sm+ 14st+ 16a [fundamental number (FN) = 120] in males and 15m+ 24sm+14st+15a (FN = 121) in females and sex chromosomes ZZ/ZW. Argyrophilic nucleolar organizer regions (AgNORs) were identified in two pairs of chromosomes at different positions: short arm of the pair 21and long arm of the pair 27, matching the signals displayed by 18S FISH and indicating multiple NORs. Analysis of band C detected few blocks of constitutive heterochromatin in the pericentromeric regions of most chromosomes and the telomeric regions of some pairs, includ-ing the nucleolar pair 21. However, large blocks on the long arm of the nucleolar pair 27 still stood out. GC-rich heterochromatin (CMA3) was visualized only coincidently with nucleolar sites. Mapping of 5S rDNA sites with FISH revealed markings in eight chromosomes, demonstrat-ing synteny between the 18S and 5S sites. The data obtained for H. cf. plecostomus are important for taxonomic studies of this Amazon com-plex "H. plecostomus group". The occurrence of sex chromosomes in Amazon species of Hypostomus suggests an evolutionary event that is independent of other species in the group.

  5. Crinoids columnals (Echinodermata) of the Ererê Formation (late Eifelian-early Givetian, Amazon Basin), State of Pará, Brazil

    Science.gov (United States)

    Scheffler, S. M.; Fernandes, A. C. S. F.; da Fonseca, V. M. M.

    2014-01-01

    The faunal composition of stalked echinoderms in the Brazilian Devonian is still largely unknown despite the great abundance of crinoids in the shallow epicontinental seas of the Paleozoic. The first Devonian crinoids of Brazil, recorded in the literature in 1875 and 1903, were from the sedimentary rocks of the Ererê Formation in the Amazon Basin. Since then, the echinoderms of this formation have not been studied. This study, based on isolated pluricolumnals and columnals, described and identified Botryocrinus meloi n. sp., the first record for this genus in Brazil. In addition to this species, two other morphological patterns were identified: Tjeecrinus sp. and Morphotype AM/Er-01. The form of occurrence of the crinoid material and the paleoautoecology of B. meloi allow preliminary characterization of the habitat as a moderately deep water with weak to moderate currents and soft substrate. The similarity between B. meloi and Botryocrinus montguyonensis and of Tjeecrinus? sp. and T. crassijugatus, from the Devonian of the Armorican and Rhenan Massif, represents new evidence for the existence of contact between the faunas of the Amazon Basin with those of northern Gondwana and Armorica during the Middle Devonian.

  6. Differentiation in the fertility of Inceptisols as related to land use in the upper Solimões river region, western Amazon.

    Science.gov (United States)

    Moreira, Fatima Maria de Souza; Nóbrega, Rafaela Simão Abrahão; Jesus, Ederson da Conceição; Ferreira, Daniel Furtado; Pérez, Daniel Vidal

    2009-12-20

    The Upper Solimões river region, western Amazon, is the homeland of indigenous populations and contains small-scale agricultural systems that are important for biodiversity conservation. Although traditional slash-and-burn agriculture is being practiced over many years, deforestation there is relatively small compared to other Amazon regions. Pastures are restricted to the vicinity of cities and do not spread to the small communities along the river. Inceptisols are the main soil order (>90%) in the area and have unique attributes including high Al content and high cation exchange capacity (CEC) due to the enrichment of the clay fraction with 2:1 secondary aluminosilicates. Despite its importance, few studies have focussed on this soil order when considering land use effects on the fertility of Amazon soils. Thus, the objective of this study was to evaluate changes in soil fertility of representative land use systems (LUSs) in the Upper Solimões region, namely: primary rainforest, old secondary forest, young secondary forest, agroforestry, pasture and agriculture. LUSs were significantly differentiated by the chemical attributes of their topsoil (0-20 cm). Secondary forests presented soil chemical attributes more similar to primary rainforest areas, while pastures exhibited the highest dissimilarity from all the other LUSs. As a whole, soil chemical changes among Inceptisols dominated LUSs showed patterns that were distinct from those reported from other Amazon soils like Oxisols and Ultisols. This is probably related to the presence of high-activity clays enriched in exchangeable aluminum that heavily influenced the soil chemical reactions over the expected importance of organic matter found in most studies conducted over Oxisol and Ultisol.

  7. New records of marginal locations for American pika (Ochotona princeps) in the Western Great Basin

    Science.gov (United States)

    Constance I. Millar; Robert D. Westfall; Diane L. Delany

    2013-01-01

    We describe 46 new site records documenting occupancy by American pika (Ochotona princeps) at 21 locations from 8 mountain regions in the western Great Basin, California, and Nevada. These locations comprise a subset of sites selected from regional surveys to represent marginal, isolated, or otherwise atypical pika locations, and to provide...

  8. Transport of North African dust from the Bodélé depression to the Amazon Basin: a case study

    Directory of Open Access Journals (Sweden)

    Y. Ben-Ami

    2010-08-01

    Full Text Available Through long-range transport of dust, the North-African desert supplies essential minerals to the Amazon rain forest. Since North African dust reaches South America mostly during the Northern Hemisphere winter, the dust sources active during winter are the main contributors to the forest. Given that the Bodélé depression area in southwestern Chad is the main winter dust source, a close link is expected between the Bodélé emission patterns and volumes and the mineral supply flux to the Amazon.

    Until now, the particular link between the Bodélé and the Amazon forest was based on sparse satellite measurements and modeling studies. In this study, we combine a detailed analysis of space-borne and ground data with reanalysis model data and surface measurements taken in the central Amazon during the Amazonian Aerosol Characterization Experiment (AMAZE-08 in order to explore the validity and the nature of the proposed link between the Bodélé depression and the Amazon forest.

    This case study follows the dust events of 11–16 and 18–27 February 2008, from the emission in the Bodélé over West Africa (most likely with contribution from other dust sources in the region the crossing of the Atlantic Ocean, to the observed effects above the Amazon canopy about 10 days after the emission. The dust was lifted by surface winds stronger than 14 m s−1, usually starting early in the morning. The lofted dust, mixed with biomass burning aerosols over Nigeria, was transported over the Atlantic Ocean, and arrived over the South American continent. The top of the aerosol layer reached above 3 km, and the bottom merged with the boundary layer. The arrival of the dusty air parcel over the Amazon forest increased the average concentration of aerosol crustal elements by an order of magnitude.

  9. A century of Amazon burning driven by Atlantic climate

    Science.gov (United States)

    Makou, M.; Thompson, L. G.; Davis, M. E.; Eglinton, T. I.

    2011-12-01

    Very little is known about annual burning trends in the Amazon Basin prior to remote sensing of fires beginning in the late 1970's. Fires reduce Amazon forest biomass and species richness, release pollutant aerosols, and impact the carbon cycle, compelling further investigation of fire-climate dynamics. We measured organic compounds derived from vegetation burning in ice core samples from the Quelccaya Ice Cap in Peru at better than annual resolution to reconstruct wet and dry season burning throughout the Twentieth Century. Variations in the abundance of methyl hexadecanoate, which is produced by thermal alteration of vascular plant alkanoic acids, were used as a proxy for past fire activity. Concentrations of this compound in Quelccaya ice varied strongly on seasonal, interannual, and decadal time scales over the last 100 years, with high-amplitude dry season variability and muted, decadal-scale changes in wet season fire activity. Decade-long periods of repeatedly enhanced burning occurred during the 1930's and 1960's when dry season precipitation was perpetually reduced, as evidenced by low stages of the Rio Negro. These decadal trends suggest that changes in dry season precipitation drive fire activity in the western Amazon and highlight the potential of Amazon forests to undergo repeated strong burning. Fires occurred during years when sea surface temperatures (SSTs) in the north tropical Atlantic were elevated and the north-south tropical Atlantic SST gradient was enhanced; this SST pattern likely displaced the intertropical convergence zone northward, driving subsidence and drought in the western and southern Amazon basin. Thus, our novel ice core record suggests that Amazon forest fire activity during the Twentieth Century was driven primarily by Atlantic climate processes, and future forest health will depend heavily on the evolution of tropical climate.

  10. The NH4+-NO3--Cl--SO42--H2O aerosol system and its gas phase precursors at a pasture site in the Amazon Basin: How relevant are mineral cations and soluble organic acids?

    NARCIS (Netherlands)

    Trebs, I.; Metzger, S.; Meixner, F.X.; Helas, G.N.; Hoffer, A.; Rudich, Y.; Falkovich, A.H.; Moura, M.A.L.; Silva, da R.S.; Artaxo, P.; Slanina, J.; Andreae, M.O.

    2005-01-01

    Real-time measurements of ammonia, nitric acid, hydrochloric acid, sulfur dioxide and the water-soluble inorganic aerosol species, ammonium, nitrate, chloride, and sulfate were performed at a pasture site in the Amazon Basin (Rondônia, Brazil). The measurements were made during the late dry season

  11. Hydrologic changes across western and eastern Amazon during the late Holocene recorded in sediments from the Xingu Ria

    Science.gov (United States)

    Bertassoli, Dailson J., Jr.; Sawakuchi, Andre O.; Sawakuchi, Henrique O.; Pupim, Fabiano N.; Hartmann, Gelvam A.; Chiessi, Cristiano M.

    2017-04-01

    The Xingu River is a major tributary of the Amazon. It is a clearwater river with low sedimentary load, unique biodiversity and great socioeconomic relevance for the eastern Amazonia. The lower valley of the Xingu River was flooded after the last glacial maximum and became a lake-like channel known as Xingu Ria. Sedimentation in the Xingu Ria is under tidal influence and is mainly controlled by backwater effects related to the timing difference between the peak stages of the Xingu and the Amazon rivers. This condition allows the input and deposition of sediments of the Amazon River in the downstream sector of the Xingu Ria. This particular sedimentary dynamic records the relative sediment supplies derived from the Amazon and Xingu rivers. Thus, the sediments accumulated in the downstream sector of the Xingu Ria testimony relative shifts between the water discharges of the Amazon and Xingu catchments during the late Holocene, when major physiographic changes were absent. We obtained a 3.7 m long sediment core at the confluence of both rivers and sampled it at every 2 cm for inorganic geochemistry, diatom and magnetic susceptibility analyses. Ages of sediment deposition were constrained by optically stimulated luminescence (OSL) and radiocarbon dating. OSL dating was carried out using a single aliquot regeneration dose (SAR) protocol applied to quartz in fine silt and fine sand grain sizes. The equivalent doses ranged from 0.3 to 3.1 Gy (Central Age Model) and the dose rate values were approximately 2.5 Gy/ka, giving ages from 118±81 (10 cm depth) to 1251±211 (363 cm depth) years. Samples of suspended sediments show that Fe/K and Ti/K ratios increase during the wet season of the Xingu River. Additionally, sediments of the Xingu River have higher Fe/K and Ti/K ratios compared to sediments of the Amazon River. Preliminary results indicate positive anomalies in the relative percentages of Fe and Ti from 700 to 300 years ago. This is interpreted as a relative increase

  12. Impact of soil hydrology formulation on water budget and phenology over the Amazon basin. Sensitivity of simulated hydrology to the dry-season length.

    Science.gov (United States)

    Guimberteau, Matthieu; Ciais, Philippe; Ducharne, Agnès; Boisier, Juan-Pablo; Peng, Shushi; De Weirdt, Marjolein; Verbeeck, Hans

    2014-05-01

    The role of soil moisture in controlling evapotranspiration (ET) is important over the Amazon basin, and particularly in south Amazonia, where a high rate of water recycling is sustained through transpiration. Thus, soil moisture parametrization in Land Surface Models (LSMs) plays a critical role in accurate modeling of the hydro-climatology and CO2 fluxes. Multilayer schemes have been introduced in LSMs to better describe the water diffusion through the soil. The main question we address here is "Does the use of a soil diffusion scheme, rather than a simpler bucket-type scheme, improve the simulation of water storage dynamics and water fluxes?". For the first time, we compare two soil models embedded in ORCHIDEE coupled to the same river routing scheme and interactive phenology/carbon cycle module: a simple 2 layer soil scheme with a bucket topped by an evaporative layer (2LAY) and an 11 layer soil diffusion scheme (11LAY). We tested their different impacts on the estimated Amazonian water budget and carbon flux dynamics, which are compared with several datasets, at the scale of the five major tributary sub-basins. The use of the 11LAY did not significantly change the Amazonian water budget simulation when compared to the 2LAY. However, the higher water holding capacity of the soil and the physically based representation of runoff and drainage in the 11LAY resulted in higher dynamic of soil water storage variations and improved simulation of the total terrestrial water storage when compared to GRACE satellite estimates. The greater soil water storage within the 11LAY resulted in increased dry-season ET in the southeastern sub-basins such as the Xingu. Lower plant water stress simulated by the 11LAY led to better simulation of the seasonal cycle of photosynthesis (GPP) when compared to a GPP data-driven model based upon eddy-covariance and satellite greenness measurements. Simulated LAI was consequently higher with the 11LAY but exhibited too low a variation when

  13. The Origin of Basin of Great Lakes in Western Mongolia: Glaciated Super Valley, Not Super Flooding

    Science.gov (United States)

    Khukhuudei, Ulambadrakh; Otgonbayar, Orolzodmaa

    2015-04-01

    Research for morphology, its origin of the Basin of Great Lakes in Western Mongolia, is few and far between, particularly, any in recent years. The origin of the morphology of the basin presents a new study, combining previous study materials, their results and interpreting the digital photos. Also the main bases of theory is Pleistocene Last Glacial Maximum distribution. Many scholars have proven that global glaciation covered many areas of the Northern Hemisphere during the Pleistocene era. This global glaciation occurred in the northwest part of Mongolia to Mongolian Altay, Khangay and Khuvsgul mountain range. At the same time, the present appearance of basin that developed inheriting since the Mesozoic era, forms by global glaciation. The morphology of Basin of Great Lakes is super trough or glaciated super valley. At current day, "knock and lochan" topography (scoured region) and rock drumlins lie in the central part of the basin. Huge meltwater from this glaciation formed Shargasub-basin as a super kettle hole by erosion and overflowed water from it formed pluvial basins or big lakes in the Lake Valley.

  14. The Late Quaternary biogeographic histories of some Great Basin mammals (western USA)

    Science.gov (United States)

    Grayson, Donald K.

    2006-11-01

    The Great Basin of arid western North America provides one of the most detailed late Pleistocene and Holocene mammal records available for any part of the world, though the record is by far strongest for small mammals. Of the 35 genera of now-extinct North American Pleistocene mammals, 19 are known to have occurred in the Great Basin, a list that is likely to be complete or nearly so. Of these 19, seven can be shown to have survived beyond 12,000 radiocarbon years ago, a proportion similar to that for North America as a whole. Horses, camels, mammoth, and helmeted musk-oxen appear to have been the most abundant of these genera. Pygmy rabbits ( Brachylagus idahoensis), yellow-bellied marmots ( Marmota flaviventris), and bushy-tailed woodrats ( Neotoma cinerea) declined in abundance at the end of the Pleistocene, at about the same time as populations south of their current arid western distributional boundary were extirpated. Subsequent declines occurred during the hot/dry middle Holocene. Pygmy rabbits also declined as modern pinyon-juniper woodlands developed across the Great Basin. The Snake Range of eastern Nevada has seen the late Pleistocene or Holocene extinction of both northern pocket gophers ( Thomomys talpoides) and pikas ( Ochotona princeps). Coupled with the rarity of yellow-bellied marmots here, these histories make the Snake Range a biogeographic oddity. These and other Great Basin mammal histories provide significant insights into the possible responses of Great Basin small mammals to global warming.

  15. An appraisal of the sediment yield in western Mediterranean river basins.

    Science.gov (United States)

    Buendia, C; Herrero, A; Sabater, S; Batalla, R J

    2016-12-01

    The number of studies assessing soil erosion and sediment transport has increased with the aim of achieving sustainable land and water management. Mediterranean rivers have been the object of many of these studies due to their naturally high values of sediment fluxes and a higher vulnerability under future climate scenarios. In this context, we attempt to use empirical relationships to (i) further assess the relation between sediment yield and basin scale and (ii) provide an update on the main drivers controlling sediment yield in these particular river systems. For this purpose, sediment yield data (from reservoir sedimentation surveys and sediment transport records) was collected from >100 locations distributed across the western Mediterranean area, with basin areas ranging from 1 to 100,000km(2). Quantile Regression analysis was used to assess the correlation between basin area and sediment yield, while additional basin-scale descriptors were related to sediment yield by means of multiple regression analysis. Results showed the complexity in the relationship between basin scale and sediment yield, with changes in supply conditions with increasing area introducing uncertainties in the correlation. Despite the large scatter, analysis pointed towards the same direction and area appeared to be the main constrain for the maximum value of sediment yield that can be found at a specific basin scale. Results from the multiple regression indicated that variables representing basin's physiography, climate and land use were highly correlated with the basins' sediment yield. Also, a better model performance was obtained when using total sediment yield instead of specific values (per unit area). Validation showed model instability, potentially due to data limitations and the use of catchments with varying characteristics. Overall, despite providing some insights on the correlation between sediment yield and basin-scale characteristics, validation prevented direct

  16. Hepatitis B virus, syphilis, and HIV seroprevalence in pregnant women and their male partners from six indigenous populations of the Peruvian Amazon Basin, 2007-2008.

    Science.gov (United States)

    Ormaeche, Melvy; Whittembury, Alvaro; Pun, Mónica; Suárez-Ognio, Luis

    2012-10-01

    To assess the seroprevalence of hepatitis B virus (HBV), syphilis, and HIV and associated risk factors in pregnant women and their male partners from six indigenous populations of the Peruvian Amazon Basin. A cross-sectional study was performed in six indigenous populations from the Peruvian Amazon Basin. Blood samples were obtained and tested for HBV (antibodies to the hepatitis B core antigen (anti-HBc) and hepatitis B surface antigen (HBsAg)), for syphilis (rapid plasma reagin and microhemagglutination assay for Treponema pallidum antibodies), and for HIV (ELISA and indirect immunofluorescence test). A survey was also performed to identify associated risk factors. One thousand two hundred and fifty-one pregnant women and 778 male partners were enrolled in the study. The seroprevalence of anti-HBc in pregnant women was 42.06% (95% confidence interval (CI) 39.28-44.85%) and in their male partners was 54.09% (95% CI 50.32-57.86%). The seroprevalence of HBsAg in pregnant women was 2.11% (95% CI 0.78-3.44%) and in their male partners was 3.98% (95% CI 1.87-6.08%). The seroprevalence of syphilis in pregnant women was 1.60% (95% CI 0.86-2.33%) and in their male partners was 2.44% (95% CI 1.22-3.66%). HIV seroprevalence in pregnant women was 0.16% (95% CI 0.02-0.58%) and in their male partners was 0.29% (95% CI 0.04-1.03%). Sexual risk factors were strongly related to blood markers of syphilis and HBV. Hepatitis B was found to be hyperendemic and strongly related to sexual factors, suggesting an important sexual component in the transmission of the disease in the populations studied. Syphilis was found to have an endemicity in pregnant women above the national level and this may be indicative of high mother-to-child transmission. HIV has started to show its presence in indigenous populations of the Amazon Basin and the results suggest the epidemic is concentrated. Copyright © 2012 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights

  17. Pleistocene deformations in the contexte of the Rharb foredeep basin (north western Atlantic Moroccan margin)

    Science.gov (United States)

    Maad, N.; Le Roy, P.; Sahabi, M.; Gutscher, M. A.; Dakki, M.; Hssain, M.; van Vliet-Lanoë, B.; Brahim, L. Ait; M'hammdi, N.; Trenteseaux, A.

    2009-04-01

    This study relates to the Cenozoic post rift deformations of Rharb foredeep basin in response to the Europe-Africa convergence. Here we are going to retail the tectonic structures of the Rharb basin, in particular the active front of the Prerifaine nappe in the area of Lalla Zahra. The method is based on the interpretations of the high resolution seismic reflection data acquired during the Protit2 (2003) and the Nomads cruises (2007). The surveys were conducted by the University of Brest in France and the Faculté des Sciences d'El Jadida in Morocco. They allowed to record more than 2000 km of seismic lines through the Rharb continental shelf. The integration of new data with industrial seismic lines provided by ONHYM and field observations collected along the coastline allows us to identify the formation and the recent evolution of the western termination of the Southern Rif Corridor. This coastal basin corresponds to the foredeep basin linked to the Rif Cordillera and extends southwards through the northern Moroccan Meseta that defines the foreland region of the Western Rif (Flinch,93). The integrated study clarifies the post-nappe evolution of the offshore Rharb basin during Neogene and quaternary times. A succession of deformations affect the Rharb basin with separating episodes of relaxation and quiescence. Their ages are based on chronostratigraphical attribution of mean unconformities. A Lower Pliocene episode is characterized by reactivation of faults affecting the Nappe. The uplift of the basin and the individualization of the Lallah Zarah ridge increases and controls the terrigenous fluxes. A Middle Pleistocene still active episode and corresponds to a new uplift of the two margins of the basin. Faulting remains more active in the North along the Lallah Zarah ridge and offshore Larache where large active listric faults are observed. The progressive segmentation of the basin determinates the sedimentary filling with cyclic sequences extending progressively

  18. Fish assemblages of the Casiquiare River, a corridor and zoogeographical filter for dispersal between the Orinoco and Amazon basins

    Science.gov (United States)

    Winemiller, K.O.; Lopez-Fernandez, H.; Taphorn, D.C.; Nico, L.G.; Duque, A.B.

    2008-01-01

    Aim: The aim of this study was to determine whether the Casiquiare River functions as a free dispersal corridor or as a partial barrier (i.e. filter) for the interchange of fish species of the Orinoco and Negro/Amazon basins using species assemblage patterns according to geographical location and environmental features. Location: The Casiquiare, Upper Orinoco and Upper Negro rivers in southern Venezuela, South America. Methods: Our study was based on an analysis of species presence/absence data and environmental information (11 habitat characteristics) collected by the authors and colleagues between the years 1984 and 1999. The data set consisted of 269 sampled sites and 452 fish species (> 50,000 specimens). A wide range of habitat types was included in the samples, and the collection sites were located at various points along the entire length of the Casiquiare main channel, at multiple sites on its tributary streams, as well as at various nearby sites outside the Casiquiare drainage, within the Upper Orinoco and Upper Rio Negro river systems. Most specimens and field data used in this analysis are archived in the Museo de Ciencias Naturales in Guanare, Venezuela. We performed canonical correspondence analysis (CCA) based on species presence/absence using two versions of the data set: one that eliminated sites having < 5 species and species occurring at < 5 sites; and another that eliminated sites having < 10 species and species occurring at < 10 sites. Cluster analysis was performed on sites based on species assemblage similarity, and a separate analysis was performed on species based on CCA loadings. Results: The CCA results for the two versions of the data set were qualitatively the same. The dominant environmental axis contrasted assemblages and sites associated with blackwater vs. clearwater conditions. Longitudinal position on the Casiquiare River was correlated (r2 = 0.33) with CCA axis-1 scores, reflecting clearwater conditions nearer to its origin

  19. Cold Outbreaks at the Mesoscale in the Western Mediterranean Basin: From Raincells to Rainbands

    Directory of Open Access Journals (Sweden)

    Jordi Mazon

    2017-01-01

    Full Text Available This paper investigates cold outbreaks that form offshore density currents within the whole mesoscale over the Western Mediterranean basin. Reflectivity radar and satellite images are used to detect clouds and precipitation that are associated with these density currents in the meso-α, meso-β, and meso-γ over the Western Mediterranean basin (WMB. Version 3.3 of the WRF-ARW model is used to describe the formation and evolution of these density currents and to estimate their lifetime as well as horizontal and vertical scales. Based on the observations and simulations, this paper suggests that a new perspective could effectively be adopted regarding the WMB region delineated by the Balearic Islands, the northeastern Iberian Peninsula, and the Gulf of Lion, where inland cold outbreaks develop into density currents that move offshore and can produce precipitation ranging from raincells to rainbands at the whole mesoscale.

  20. Seismic refraction investigations on the crustal structure of the western Jameson Land Basin, East Greenland

    Science.gov (United States)

    Fechner, Notker; Jokat, Wilfried

    1996-07-01

    In 1990, a combined land-sea experiment in the Hall Bredning, Scoresby Sund (East Greenland) revealed new information about the crustal structure of the Jameson Land Basin. The sediments and the upper and lower crust have been imaged by a 710-km-long network of seismic refraction lines. Our data indicate that the crust-mantle boundary is at a depth of 24 km close to the western coast of Jameson Land and deepens to 31 km toward the western termination of Hall Bredning. The sediments thin from 8-km thickness in the east to almost 0 km close to Milne Land. Our cross sections indicate that Jameson Land is an asymmetrical, half-graben shaped sedimentary basin with a N-S striking axis.

  1. Lineament and Morphometric Analysis for Watershed Development of Tarali River Basin, Western India

    Directory of Open Access Journals (Sweden)

    Vikrant Bartakke

    2013-06-01

    Full Text Available Tarali river is major tributary of River Krishna, which is flowing in western India. The study area lies between latitude 17°23' to 17°38' N and longitude 73°48' to 74°7' E. The area has steep to moderate slope and elevation ranges from 584 - 1171m above mean sea level. Basin exhibits hilly and mountain terrain forming ridges and Western Ghats with deep valley, plateaus and plain. The whole area can be obtained in topographical maps i.e. 47 G/14, 47 G/15 47 K/2, 47 K/3 covering area of about 627 sq.km, acquired from Survey of India. Present study includes lineament and morphometric analysis of Tarali River basin for management and conservation of watershed.

  2. Lunar impact basins and crustal heterogeneity: New western limb and far side data from galileo

    Science.gov (United States)

    Belton, M.J.S.; Head, J. W.; Pieters, C.M.; Greeley, R.; McEwen, A.S.; Neukum, G.; Klaasen, K.P.; Anger, C.D.; Carr, M.H.; Chapman, C.R.; Davies, M.E.; Fanale, F.P.; Gierasch, P.J.; Greenberg, R.; Ingersoll, A.P.; Johnson, T.; Paczkowski, B.; Pilcher, C.B.; Veverka, J.

    1992-01-01

    Multispectral images of the lunar western limb and far side obtained from Galileo reveal the compositional nature of several prominent lunar features and provide new information on lunar evolution. The data reveal that the ejecta from the Orientale impact basin (900 kilometers in diameter) lying outside the Cordillera Mountains was excavated from the crust, not the mantle, and covers pre-Orientale terrain that consisted of both highland materials and relatively large expanses of ancient mare basalts. The inside of the far side South Pole-Aitken basin (>2000 kilometers in diameter) has low albedo, red color, and a relatively high abundance of iron- and magnesium-rich materials. These features suggest that the impact may have penetrated into the deep crust or lunar mantle or that the basin contains ancient mare basalts that were later covered by highlands ejecta.

  3. Lunar impact basins and crustal heterogeneity - New western limb and far side data from Galileo

    Science.gov (United States)

    Belton, Michael J. S.; Head, James W., III; Pieters, Carle M.; Greeley, Ronald; Mcewen, Alfred S.; Neukum, Gerhard; Klaasen, Kenneth P.; Anger, Clifford D.; Carr, Michael H.; Chapman, Clark R.

    1992-01-01

    Multispectral images of the lunar western limb and far side obtained from Galileo reveal the compositional nature of several prominent lunar features and provide new information on lunar evolution. The data reveal that the ejecta from the Orientale impact basin (900 kilometers in diameter) lying outside the Cordillera Mountains was excavated from the crust, not the mantle, and covers pre-Orientale terrain that consisted of both highland materials and relatively large expanses of ancient mare basalts. The inside of the far side South Pole-Aitken basin (greater than 2000 kilometers in diameter) has low albedo, red color, and a relatively high abundance of iron- and magnesium-rich materials. These features suggest that the impact may have penetrated into the deep crust or lunar mantle or that the basin contains ancient mare basalts that were later covered by highlands ejecta.

  4. XXI Century Climatology of Snow Cover for the Western River Basins of the Indus River System

    CERN Document Server

    Hasson, Shabeh ul; Lucarini, Valerio

    2012-01-01

    Under changing climate, freshwater resources of Hindu Kush-Karakoram-Himalaya (HKH) region can be affected by changes in temperature and in amount, type and distribution of precipitation. This can have serious implications for the water supply and in turn threaten the food security and economic wellbeing of Indus basin. Using MODIS daily snow products (Terra & Aqua), this study focuses on the assessment of the 2000-2010 snow cover dynamics on seasonal/annual basis against geophysical parameters (aspect, elevation and slope) for the so called western river basins of Indus River System (IRS), namely Indus, Kabul, Jhelum, Astore, Gilgit, Hunza, Swat, Shigar and Shyok basins. Results show that inputs from MODIS instrument provide unprecedented better opportunity to study by using GIS techniques the snow cover dynamics in the remote areas like HKH region at such hyper-temporal and finer planar resolution. Adapted non-spectral cloud filtering techniques have significantly reduced cloud coverage and improved sno...

  5. Pluvial lakes in the Great Basin of the western United States: a view from the outcrop

    Science.gov (United States)

    Reheis, Marith C.; Adams, Kenneth D.; Oviatt, Charles G.; Bacon, Steven N.

    2014-01-01

    Paleo-lakes in the western United States provide geomorphic and hydrologic records of climate and drainage-basin change at multiple time scales extending back to the Miocene. Recent reviews and studies of paleo-lake records have focused on interpretations of proxies in lake sediment cores from the northern and central parts of the Great Basin. In this review, emphasis is placed on equally important studies of lake history during the past ∼30 years that were derived from outcrop exposures and geomorphology, in some cases combined with cores. Outcrop and core records have different strengths and weaknesses that must be recognized and exploited in the interpretation of paleohydrology and paleoclimate. Outcrops and landforms can yield direct evidence of lake level, facies changes that record details of lake-level fluctuations, and geologic events such as catastrophic floods, drainage-basin changes, and isostatic rebound. Cores can potentially yield continuous records when sampled in stable parts of lake basins and can provide proxies for changes in lake level, water temperature and chemistry, and ecological conditions in the surrounding landscape. However, proxies such as stable isotopes may be influenced by several competing factors the relative effects of which may be difficult to assess, and interpretations may be confounded by geologic events within the drainage basin that were unrecorded or not recognized in a core. The best evidence for documenting absolute lake-level changes lies within the shore, nearshore, and deltaic sediments that were deposited across piedmonts and at the mouths of streams as lake level rose and fell. We review the different shorezone environments and resulting deposits used in such reconstructions and discuss potential estimation errors. Lake-level studies based on deposits and landforms have provided paleohydrologic records ranging from general changes during the past million years to centennial-scale details of fluctuations during the

  6. Urban malaria in the Brazilian Western Amazon Region I: high prevalence of asymptomatic carriers in an urban riverside district is associated with a high level of clinical malaria

    Directory of Open Access Journals (Sweden)

    Mauro Shugiro Tada

    2007-06-01

    Full Text Available Cross sectional studies on malaria prevalence was performed in 2001, 2002, and 2004 in Vila Candelária, an urban riverside area of Porto Velho, Rondônia, in the Brazilian Western Amazon, followed by longitudinal surveys on malaria incidence. Vila Candelária is a working class district, provided with electricity, water supply, and basic sanitation. Previous preliminary surveys indicated high malaria incidence in this community. At the end of year 2000 regular diagnostic and treatment measures for malaria were introduced, with active search of febrile cases among residents. Despite of both rapid treatment of cases and relative good sanitary and housing conditions, the malaria incidence persisted at high levels during the following years with an annual parasite index of 150 to 300/1000 inhabitants. Parasite surveys in 2001, 2002, and 2004 achieved through microscopy and polymerase chain reaction to diagnose malaria showed a constant high prevalence of asymptomatic carriers for both Plasmodium falciparum and P. vivax parasites. It was concluded that asymptomatic carriers represent an important reservoirs of parasites and that the carriers might contribute to maintaining the high level of transmission. Comparing our findings to similar geo-demographic situations found in other important urban communities of the Brazilian Amazon, we propose that asymptomatic carriers could explain malaria's outbreaks like the one recently observed in Manaus.

  7. Reserve estimates in western basins: Unita Basin. Final report, Part III

    Energy Technology Data Exchange (ETDEWEB)

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    1995-10-01

    This study characterizes an extremely large gas resource located in low permeability, sandstone reservoirs of the Mesaverde group and Wasatch formation in the Uinta Basin, Utah. Total in-place resource is estimated at 395.5 Tcf. Via application of geologic, engineering and economic criteria, the portion of this resource potentially recoverable as reserves is estimated. Those volumes estimated include probable, possible and potential categories and total 3.8 Tcf as a mean estimate of recoverable gas for all plays considered in the basin. Two plays were included in this study and each was separately analyzed in terms of its tight gas resource, established productive characteristics and future reserves potential based on a constant $2/Mcf wellhead gas price scenario. A scheme has been developed to break the overall resource estimate down into components that can be considered as differing technical and economic challenges that must be overcome in order to exploit such resources; in other words, to convert those resources to economically recoverable reserves. About 82.1% of the total evaluated resource is contained within sandstones that have extremely poor reservoir properties with permeabilities considered too low for commerciality using current frac technology.

  8. Biodiversity of deep-sea demersal megafauna in western and central Mediterranean basins

    Directory of Open Access Journals (Sweden)

    Samuele Tecchio

    2011-06-01

    Full Text Available Abundance, biomass and diversity patterns of bathyal and abyssal Mediterranean megafauna (fishes and invertebrates were analyzed in the western Balearic Sea, the western Ionian Sea and the eastern Ionian Sea. Sampling was conducted with a Otter-trawl Maireta System (OTMS at depths ranging from 600 to 4000 m. A series of ecological indicators were computed: total abundance and biomass, Margalef species richness, Shannon-Wiener diversity and Pielou’s index of evenness. A multidimensional scaling was applied, indicating that the megafauna communities were grouped by depth, while geographic area had a less defined influence. Margalef richness declined with depth in all three areas, but more steeply in the western Ionian Sea. Pielou’s evenness behaved differently in the three zones, showing a V-shaped curve in the eastern Ionian while showing a decreasing pattern in the other two areas. At lower slope depths, massive presence of the fishes Alepocephalus rostratus in the western basin and Bathypterois mediterraneus in the central basin caused a sharp reduction in evenness.

  9. Climate variability, snow, and physiographic controls on storm hydro graphs in small forested basins, western Cascades, Oregon

    Science.gov (United States)

    Reed M. Perkins; Julia A. Jones

    2008-01-01

    Large floods are often attributed to the melting of snow during a rain event. This study tested how climate variability, snowpack presence, and basin physiography were related to storm hydrograph shape in three small (2) basins with old-growth forest in western Oregon. Relationships between hydrograph characteristics and precipitation...

  10. Characterization of Shigella spp. by antimicrobial resistance and PCR detection of ipa genes in an infantile population from Porto Velho (Western Amazon region, Brazil

    Directory of Open Access Journals (Sweden)

    Tatiane Silva

    2008-11-01

    Full Text Available The incidence of Shigella spp. was assessed in 877 infants from the public hospital in Rondônia (Western Amazon region, Brazil where Shigella represents the fourth cause of diarrhea. Twenty-five isolates were identified: 18 were Shigella flexneri, three Shigella sonnei, three Shigella boydii and one Shigella dysenteriae. With the exception of S. dysenteriae, all Shigella spp. isolated from children with diarrhea acquired multiple antibiotic resistances. PCR detection of ipa virulence genes and invasion assays of bloody diarrhea and fever (colitis were compared among 25 patients testing positive for Shigella. The ipaH and ipaBCD genes were detected in almost all isolates and, unsurprisingly, all Shigella isolates associated with colitis were able to invade HeLa cells. This work alerts for multiple antibiotic resistant Shigella in the region and characterizes presence of ipa virulence genes and invasion phenotypesin dysenteric shigellosis.

  11. Seismo and sequence stratigraphy of Cenozoic units of the Morondava Basin, offshore western Madagascar

    Science.gov (United States)

    Kaufmann, Dirk; Stollhofen, Harald; Klimke, Jennifer; Franke, Dieter

    2015-04-01

    The N-S trending Morondava Basin extends in width from western onshore Madagascar over about 350 km westwards to the offshore Davie Ridge in the Mozambique Channel. Although basin formation was initiated during Karoo times, the main basin evolution took place during Jurassic rifting and subsequent drifting until middle Cretaceous as a result of Gondwana breakup (Geiger et al., 2004). Contemporaneous to the separation of India and Madagascar widespread flood basalts were emplaced during the late Cretaceous (Storey et al., 1995). Present knowledge of the Morondava Basin is mainly based on outcrop studies, seismic surveys and borehole information (e.g. Geiger et al., 2004), gathered in western onshore Madagascar, although the fast majority of the basin, including its depocenter is located offshore in the Mozambique Channel, now at up to 3,500 m water depth. Almost all of the recent offshore studies of the Morondava Basin rely on industrial data but up to date publications of exploration results are generally rare and mostly anonymized. Our study aims to extend knowledge, particularly on the offshore seismic and sequence stratigraphy of the Morondava Basin. A key question is also to test the proposed tectonic stability of the Davie Ridge over the last 40 Ma. For this purpose 12 seismic profiles and bathymetric data, acquired in early 2014 by RV SONNE, are interpreted. Most of the profiles cover the distal deep marine areas of the northern Morondava Basin between the Davie Ridge and the shelf break of Madagascar. Top Cretaceous, Top Eocene, Top Oligocene, the Middle Miocene Unconformity and the Base Pliocene, are mapped as major seismic marker horizons. Especially shelf and slope sedimentary units are important resources to reconstruct the tectonostratigraphic basin evolution. At the continental slope diffuse to chaotic seismic pattern of Miocene and younger age are identified which are subdivided by laterally continuous, high frequency reflectors with a higher

  12. Annual Variations in Water Storage and Precipitation in the Amazon Basin: Bounding Sink Terms in the Terrestrial Hydrological Balance using GRACE Satellite Gravity Data

    Science.gov (United States)

    Crowley, John W.; Mitrovica, Jerry X.; Bailey, Richard C.; Tamisiea, Mark E.; Davis, James L.

    2007-01-01

    We combine satellite gravity data from the Gravity Recovery and Climate Experiment (GRACE) and precipitation measurements from the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center's (CPC) Merged Analysis of Precipitation (CMAP) and the Tropical Rainfall Measuring Mission (TRMM), over the period from mid-2002 to mid-2006, to investigate the relative importance of sink (runoff and evaporation) and source (precipitation) terms in the hydrological balance of the Amazon Basin. When linear and quadratic terms are removed, the time series of land water storage variations estimated from GRACE exhibits a dominant annual signal of 250 mm peak-to-peak, which is equivalent to a water volume change of approximately 1800 cubic kilometers. A comparison of this trend with accumulated (i.e., integrated) precipitation shows excellent agreement and no evidence of basin saturation. The agreement indicates that the net runoff and evaporation contributes significantly less than precipitation to the annual hydrological mass balance. Indeed, raw residuals between the detrended water storage and precipitation anomalies range from plus or minus 40 mm. This range is consistent with streamflow measurements from the region, although the latter are characterized by a stronger annual signal than ow residuals, suggesting that runoff and evaporation may act to partially cancel each other.

  13. Characterization, analysis and dating of archaeological ceramics from the Amazon basin through nuclear techniques; Caracterizacao, analise e datacao de ceramicas arqueologicas da Bacia Amazonica atraves de tecnicas nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Latini, Rose Mary

    1998-07-01

    The aim of this work is to contribute to the research in the reconstruction of part of the pre-history of the Amazon Basin by means of an analytical methods combined with multivariate analysis, given a analytic basis that can be continued by the archaeological work, through the identification, classification, provenance and dating the ceramics found in different archaeological sites of the Hydro graphic Basin of the Purus river. Neutron activation analysis in conjunction multivariate statistical methods were used for the identification and classification and thermoluminescence was used for the dating. Chemical composition results were in better agreement with archaeological classification for the archaeologically define Iquiri, Quinan and Xapuri phases and less characteristics the Iaco and Jacuru archaeological phase were not well characterized. An homogeneous group was established by most of the samples collected from the Los Angeles Archaeological Site (LA) and was distinct from all the other groups analysed. The provenance studies made with ceramics collected at this site shows that they were made with clay from nearby river (Rio Ina). From the LA ceramics dating the average date of site occupation was 1660 years. The ceramic dating results from the external wall of a circular earth wall construction confirm the relation with the local pre-history. Beyond the Acre material two urns were dated from the Archaeological Site Morro Grande and Sao Jose at Araruama, Rio de Janeiro. (author)

  14. Hydrological processes in glacierized high-altitude basins of the western Himalayas

    Science.gov (United States)

    Jeelani, Ghulam; Shah, Rouf A.; Fryar, Alan E.; Deshpande, Rajendrakumar D.; Mukherjee, Abhijit; Perrin, Jerome

    2017-09-01

    Western Himalaya is a strategically important region, where the water resources are shared by China, India and Pakistan. The economy of the region is largely dependent on the water resources delivered by snow and glacier melt. The presented study used stable isotopes of water to further understand the basin-scale hydro-meteorological, hydrological and recharge processes in three high-altitude mountainous basins of the western Himalayas. The study provided new insights in understanding the dominant factors affecting the isotopic composition of the precipitation, snowpack, glacier melt, streams and springs. It was observed that elevation-dependent post-depositional processes and snowpack evolution resulted in the higher isotopic altitude gradient in snowpacks. The similar temporal trends of isotopic signals in rivers and karst springs reflect the rapid flow transfer due to karstification of the carbonate aquifers. The attenuation of the extreme isotopic input signal in karst springs appears to be due to the mixing of source waters with the underground karst reservoirs. Basin-wise, the input-output response demonstrates the vital role of winter precipitation in maintaining the perennial flow in streams and karst springs in the region. Isotopic data were also used to estimate the mean recharge altitude of the springs.

  15. Eustatic and tectonic change effects in the reversion of the transcontinental Amazon River drainage system

    Directory of Open Access Journals (Sweden)

    Mario Vicente Caputo

    Full Text Available ABSTRACT: The development of the transcontinental Amazon River System involved geological events in the Andes Chain; Vaupés, Purus and Gurupá arches; sedimentary basins of the region and sea level changes. The origin and age of this river have been discussed for decades, and many ideas have been proposed, including those pertaining to it having originated in the Holocene, Pleistocene, Pliocene, Late Miocene, or even earlier times. Under this context, the geology of the sedimentary basins of northern Brazil has been analyzed from the Mesozoic time on, and some clarifications are placed on its stratigraphy. Vaupés Arch, in Colombia, was uplifted together with the Andean Mountains in the Middle Miocene time. In the Cenozoic Era, the Purus Arch has not blocked this drainage system westward to marine basins of Western South America or eastward to the Atlantic Ocean. Also the Gurupá Arch remained high up to the end of Middle Miocene, directing this drainage system westward. With the late subsidence and breaching of the Gurupá Arch and a major fall in sea level, at the beginning of the Late Miocene, the Amazon River quickly opened its pathway to the west, from the Marajó Basin, through deep headward erosion, capturing a vast drainage network from cratonic and Andean areas, which had previously been diverted towards the Caribbean Sea. During this time, the large siliciclastic influx to the Amazon Mouth (Foz do Amazonas Basin and its fan increased, due to erosion of large tracts of South America, linking the Amazon drainage network to that of the Marajó Basin. This extensive exposure originated the Late Miocene (Tortonian unconformity, which marks the onset of the transcontinental Amazon River flowing into the Atlantic Ocean.

  16. [Proof of the indigenous nature of Populus alba L. in the western Mediterranean Basin].

    Science.gov (United States)

    Roiron, Paul; Ali, Adam A; Guendon, Jean-Louis; Carcaillet, Christopher; Terral, Jean-Frédéric

    2004-02-01

    Around the western Mediterranean Basin, the ecological status of Populus alba, whether indigenous or introduced, is controversial. This note presents new palaeobotanical data based on analyses of leaf imprints from a travertine formation located in southern France. This travertine presents two levels with Populus alba imprints. The oldest level is dated back by 14C to the Early Holocene, i.e., 8890 +/- 70 BP. This demonstrates that Populus alba is an autochthonous species of the southern-France vegetation, removing speculations reporting that its distribution area was greatly influenced by Roman civilization. Finally, we discuss this new data in regard to other Pleistocene and Holocene deposits circum the Mediterranean Basin and in Europe, where this species was identified.

  17. Agribusiness geothermal energy utilization potential of Klamath and Western Snake River Basins, Oregon. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lienau, P.J.

    1978-03-01

    Resource assessment and methods of direct utilization for existing and prospective food processing plants have been determined in two geothermal resource areas in Oregon. Ore-Ida Foods, Inc. and Amalgamated Sugar Company in the Snake River Basin; Western Polymer Corporation (potato starch extraction) and three prospective industries--vegetable dehydration, alfalfa drying and greenhouses--in the Klamath Basin have been analyzed for direct utilization of geothermal fluids. Existing geologic knowledge has been integrated to indicate locations, depth, quality, and estimated productivity of the geothermal reservoirs. Energy-economic needs and balances, along with cost and energy savings associated with field development, delivery systems, in-plant applications and fluid disposal have been calculated for interested industrial representatives.

  18. Kinematic Evolution of the Western Pyrenees Thrust Front From Paleomagnetic Analysis on its Foreland Basin.

    Science.gov (United States)

    Almar, Y.; Beamud, E.; Muñoz, J. A.; Garcés, M.; Murelaga, X.

    2007-12-01

    The Pyrenees is a collisional orogen formed during the Alpine orogeny. Its southwestern frontal thrust was originated as a result of the Cenozoic inversion of preexisting extensional faults. The emplacement of the frontal thrust in the Western Pyrenees generated a foreland basin, which locally accumulated more than 4,500 meters of Tertiary sediments. The kinematic evolution of the Western Pyrenees thrust front is poorly constrained due to the scarcity of reliable age constraints within the Tertiary sediments. However, the good exposure conditions of syntectonic continental deposits in its foreland basin makes it an excellent scenario to carry out paleomagnetic and structural studies in order to unravel the kinematic history, geometry and evolution of the thrust front. A magnetostratigraphic composite section along the continental basin infill was sampled covering up to 3,000 m of succession. Correlation of the local magnetostratigraphy with the GPTS was helped by a new mammal fossil locality found in continental sediments and attributed to the Agenian local biozone Y (MN2D). The cronostratigraphy of the tectosedimentary units, ranging from lower Oligocene (Cr12r) to lower Miocene, provides further constraints on the timing of two main tectosedimentary events recorded as major unconformities within the basin infill. From this study, sedimentation rates have been also obtained. The analysis of several paleomagnetic sites revealed that no vertical axes rotations occurred in the Tertiary sediments regardless superimposed folding with oblique axes could be observed, and the proximity of adjacent structures as the Estella diapir and the Pamplona fault. Finally, the analysis of the anisotropy of magnetic susceptibility together with collected sedimentary data suggests that magnetic fabrics record both, a depositional and tectonic fabric.

  19. Dynamic Subsidence across the Late Cretaceous Western Interior Basin in Response to Farallon Slab Subduction

    Science.gov (United States)

    Liu, S.; Nummedal, D.; Liu, L.

    2015-12-01

    The United States Cretaceous Western Interior Basin has long been considered a foreland basin, driven by the Sevier thrust and associated basin sediment loads. However, flexural studies demonstrate that this effect exists only within a narrow band in front of the thrust belt. Most of the basin appears to be due to mantle flow-induced dynamic subsidence associated with Farallon plate subduction. Here we show how the components of evolving long-wavelength dynamic subsidence and flexural subsidence created the accommodation space and controlled the stratigraphy across the western United Sates, based on the correlated stratigraphic sections across central Utah-Colorado and southern Wyoming.These backstripped subsidence data reveal a component of continuously evolving long-wavelength dynamic subsidence, in addition to subsidence driven by the Sevier thrust belt and associated sediment loads. The loci of maximum rates of this dynamic subsidence moved eastward from ~98 to 74 Ma in phase with the west-to-east passage of the Farallon slab, as reconstructed from tomography based on quantitative inverse models. These subsidence data allow testing of existing subduction models and confirm the dynamic-topography driven nature of the Western Interior Basin. The results seem to support that the depocenters track the trough of dynamic subsidence with ca.18 Myr cycles through time and space and the stratigraphic patterns of large-scale progradation, eastward migration of depocenter, and regional clinoform-like downlap are related with the dynamic subsidence. Interpretation of these data also provides more insights into the repeated, ca.2 to 6 Myr cycles of thrust-induced subsidence in front of the thrust belt, which control the local eastward progradation of the sand bodies from the thrust belt. The dynamic, flexural subsidence and eustatic sea level changes interacted and controlled the timing and distribution of unconformities. Our work shows how the stratigraphy precisely

  20. Inferring lateral density variations in Great Geneva Basin, western Switzerland from wells and gravity data.

    Science.gov (United States)

    Carrier, Aurore; Lupi, Matteo; Clerc, Nicolas; Rusillon, Elme; Do Couto, Damien

    2017-04-01

    In the framework of sustainable energy development Switzerland supports the growth of renewable energies. SIG (Services Industriels de Genève) and the Canton of Geneva intend to develop the use of hydrothermal energy in western Switzerland. As a Mesozoïc-formed sedimentary basin, the Great Geneva Basin (GGB) shares geological and petrophysical similarities with the Munich area (Baviera, Germany) and Paris Basin (France). The latter already provide significant amounts of geothermal energy for district heating. The prospection phase has been launched in 2014 by SIG and aims at identifying relevant geological units and defining their geometries. Lower Cretaceous and Tertiary geological units have first been targeted as potential layers. At the depth we find these units (and according to the normal geothermal gradient), low enthalpy geothermal resources are rather expected. In this framework, our study aims at constraining and refining lateral and vertical heterogeneities of Quaternary to Cretaceous sedimentary layers in GGB. Linear velocity law is inverted at wells and then interpolated to the whole basin for each geological layer. Using time pickings from available data and Quaternary information from previous studies time to depth conversion is performed. Thickness map of every geological unit is then produced. Tertiary thickness ranges from 0 m at the NW border of the GGB at the foothill of the Jura Mountains to 3000 m in the SE of the GGB at the border with the French Alps. These observations are consistent with field and well observations. The produced thickness map will be used as a geometry support for gravity data inversion and then density lateral variations estimation. Unconstrained, and a priori constrained inversion has been performed in GGB using Gauss-Newton algorithms. Velocity versus density relationships will then enable to refine velocity law interpolation. Our procedure allowed us to reduce the uncertainty of key target formation and represents an

  1. Do dynamic global vegetation models capture the seasonality of carbon fluxes in the Amazon basin? A data-model intercomparison.

    Science.gov (United States)

    Restrepo-Coupe, Natalia; Levine, Naomi M; Christoffersen, Bradley O; Albert, Loren P; Wu, Jin; Costa, Marcos H; Galbraith, David; Imbuzeiro, Hewlley; Martins, Giordane; da Araujo, Alessandro C; Malhi, Yadvinder S; Zeng, Xubin; Moorcroft, Paul; Saleska, Scott R

    2017-01-01

    To predict forest response to long-term climate change with high confidence requires that dynamic global vegetation models (DGVMs) be successfully tested against ecosystem response to short-term variations in environmental drivers, including regular seasonal patterns. Here, we used an integrated dataset from four forests in the Brasil flux network, spanning a range of dry-season intensities and lengths, to determine how well four state-of-the-art models (IBIS, ED2, JULES, and CLM3.5) simulated the seasonality of carbon exchanges in Amazonian tropical forests. We found that most DGVMs poorly represented the annual cycle of gross primary productivity (GPP), of photosynthetic capacity (Pc), and of other fluxes and pools. Models simulated consistent dry-season declines in GPP in the equatorial Amazon (Manaus K34, Santarem K67, and Caxiuanã CAX); a contrast to observed GPP increases. Model simulated dry-season GPP reductions were driven by an external environmental factor, 'soil water stress' and consequently by a constant or decreasing photosynthetic infrastructure (Pc), while observed dry-season GPP resulted from a combination of internal biological (leaf-flush and abscission and increased Pc) and environmental (incoming radiation) causes. Moreover, we found models generally overestimated observed seasonal net ecosystem exchange (NEE) and respiration (R e ) at equatorial locations. In contrast, a southern Amazon forest (Jarú RJA) exhibited dry-season declines in GPP and R e consistent with most DGVMs simulations. While water limitation was represented in models and the primary driver of seasonal photosynthesis in southern Amazonia, changes in internal biophysical processes, light-harvesting adaptations (e.g., variations in leaf area index (LAI) and increasing leaf-level assimilation rate related to leaf demography), and allocation lags between leaf and wood, dominated equatorial Amazon carbon flux dynamics and were deficient or absent from current model

  2. Evolution of the Paleogene succession of the western Himalayan foreland basin

    Directory of Open Access Journals (Sweden)

    B.P. Singh

    2013-03-01

    Full Text Available The Paleogene succession of the Himalayan foreland basin is immensely important as it preserves evidence of India-Asia collision and related records of the Himalayan orogenesis. In this paper, the depositional regime of the Paleogene succession of the Himalayan foreland basin and variations in composition of the hinterland at different stages of the basin developments are presented. The Paleogene succession of the western Himalayan foreland basin developed in two stages, i.e. syn-collisional stage and post-collisional stage. At the onset, chert breccia containing fragments derived from the hanging walls of faults and reworked bauxite developed as a result of erosion of the forebulge. The overlying early Eocene succession possibly deposited in a coastal system, where carbonates represent barriers and shales represent lagoons. Up-section, the middle Eocene marl beds likely deposited on a tidal flat. The late Eocene/Oligocene basal Murree beds, containing tidal bundles, indicate that a mixed or semi-diurnal tidal system deposited the sediments and the sedimentation took place in a tide-dominated estuary. In the higher-up, the succession likely deposited in a river-dominated estuary or in meandering rivers. In the beginning of the basin evolution, the sediments were derived from the Precambrian basement or from the metasediments/volcanic rocks possessing terrains of the south. The early and middle Eocene (54.7–41.3 Ma succession of the embryonic foreland possibly developed from the sediments derived from the Trans-Himalayan schists and phyllites and Indus ophiolite of the north during syn-collisional stage. The detrital minerals especially the lithic fragments and the heavy minerals suggest the provenance for the late Eocene/Oligocene sequences to be from the recycled orogenic belt of the Higher Himalaya, Tethyan Himalaya and the Indus-suture zone from the north during post-collisional stage. This is also supported by the paleocurrent

  3. Applying NASA Imaging Radar Datasets to Investigate the Geomorphology of the Amazon's Planalto

    Science.gov (United States)

    McDonald, K. C.; Campbell, K.; Islam, R.; Alexander, P. M.; Cracraft, J.

    2016-12-01

    The Amazon basin is a biodiversity rich biome and plays a significant role into shaping Earth's climate, ocean and atmospheric gases. Understanding the history of the formation of this basin is essential to our understanding of the region's biodiversity and its response to climate change. During March 2013, the NASA/JPL L-band polarimetric airborne imaging radar, UAVSAR, conducted airborne studies over regions of South America including portions of the western Amazon basin. We utilize UAVSAR imagery acquired during that time over the Planalto, in the Madre de Dios region of southeastern Peru in an assessment of the underlying geomorphology, its relationship to the current distribution of vegetation, and its relationship to geologic processes through deep time. We employ UAVSAR data collections to assess the utility of these high quality imaging radar data for use in identifying geomorphologic features and vegetation communities within the context of improving the understanding of evolutionary processes, and their utility in aiding interpretation of datasets from Earth-orbiting satellites to support a basin-wide characterization across the Amazon. We derive maps of landcover and river branching structure from UAVSAR imagery. We compare these maps to those derived using imaging radar datasets from the Japanese Space Agency's ALOS PALSAR and Digital Elevation Models (DEMs) from NASA's Shuttle Radar Topography Mission (SRTM). Results provide an understanding of the underlying geomorphology of the Amazon planalto as well as its relationship to geologic processes and will support interpretation of the evolutionary history of the Amazon Basin. Portions of this work have been carried out within the framework of the ALOS Kyoto & Carbon Initiative. PALSAR data were provided by JAXA/EORC and the Alaska Satellite Facility.This work is carried out with support from the NASA Biodiversity Program and the NSF DIMENSIONS of Biodiversity Program.

  4. Faulting, volcanism, and basin development along the western margin of the southern San Luis Basin segment of the Rio Grande rift, New Mexico and Colorado

    Science.gov (United States)

    Turner, K. J.; Thompson, R. A.; Cosca, M. A.; Drenth, B.; Lee, J.; Budahn, J. R.

    2011-12-01

    The San Luis Basin segment of the northern Rio Grande rift, straddling the Colorado-New Mexico border, is an asymmetrical graben where the major basin-bounding fault is on the east side. In contrast, the west side is a basin-directed dip slope surface cut by north to northwest trending faults with predominantly down-to-southwest displacement. Around 26 Ma, initial rift-related faulting formed broad, shallow basins coincident with basaltic volcanism of the Hinsdale Formation. Later episodes of rifting produced deep and narrow sub-basins generally along the eastern boundary. Basin-fill deposits along the western margin are generally thin. However, in the northern Tusas Mountains, gravity data identifies a small, yet deep, sub-basin that may contain 750 m of basin-filling Los Pinos Formation based on thickness projections derived from mapping. The Los Pinos Formation is overlain by early rift-related Hinsdale Formation basalt flows indicating this sub-basin formed as part of early rifting; the sub-basin may be a southern extension of the Monte Vista graben to the north. The stratigraphic section along the western boundary includes Precambrian basement up to volcanic rocks of the Taos Plateau volcanic field (~5-2Ma). Dips on the early-rift Miocene to Oligocene Hinsdale Formation lavas (3-5 degrees) reflect the cumulative eastward tilting corresponding to continued basin subsidence. Shallower dips (1-2 degrees) on early Pliocene volcanic rocks suggest continued subsidence up to about 3 Ma, or younger. Down-to-southwest faults accommodating eastward tilting are mostly in areas west of Pliocene volcanic rocks; individual faults offset Hinsdale Formation and older rocks by up to 200 m. The few observed faults in the Pliocene volcanic rocks have minor offset. Numerous volcanic vents are in close proximity to the faults along the western boundary. Volcanoes are commonly low to medium relief shield volcanoes with basaltic andesite composition capped by late stage cinder cones

  5. Seismic Structural Setting of Western Farallon Basin, Southern Gulf of California, Mexico.

    Science.gov (United States)

    Pinero-Lajas, D.; Gonzalez-Fernandez, A.; Lopez-Martinez, M.; Lonsdale, P.

    2007-05-01

    Data from a number of high resolution 2D multichannel seismic (MCS) lines were used to investigate the structure and stratigraphy of the western Farallon basin in the southern Gulf of California. A Generator-Injector air gun provided a clean seismic source shooting each 12 s at a velocity of 6 kts. Each signal was recorded during 6- 8 s, at a sampling interval of 1 ms, by a 600 m long digital streamer with 48 channels and a spacing of 12.5 m. The MCS system was installed aboard CICESE's (Centro de Investigacion Cientifica y de Educacion Superior de Ensenada) 28 m research vessel Francisco de Ulloa. MCS data were conventionally processed, to obtain post- stack time-migrated seismic sections. The MCS seismic sections show a very detailed image of the sub-bottom structure up to 2-3 s two-way travel time (aprox. 2 km). We present detailed images of faulting based on the high resolution and quality of these data. Our results show distributed faulting with many active and inactive faults. Our study also constrains the depth to basement near the southern Baja California eastern coast. The acoustic basement appears as a continuous feature in the western part of the study area and can be correlated with some granite outcrops located in the southern Gulf of California islands. To the East, near the center of the Farallon basin, the acoustic basement changes, it is more discontinuous, and the seismic sections show a number of diffracted waves.

  6. Mapping groundwater development costs for the transboundary Western Aquifer Basin, Palestine/Israel

    Science.gov (United States)

    MacDonald, A. M.; Ó Dochartaigh, B. É.; Calow, R. C.; Shalabi, Y.; Selah, K.; Merrett, S.

    2009-11-01

    The costs of developing groundwater in the Western Aquifer Basin vary considerably across the West Bank and Israel. One of the main reasons for this variability is the diverse hydrogeological conditions within the aquifer. Using data from recent hydrogeological investigations, an estimate of the variation of both the drilling and pumping costs was calculated and then mapped across the Upper and Lower Aquifers within the Western Aquifer Basin. These groundwater cost maps proved helpful in analyzing the impacts of hydrogeology on water supply, and also in communicating complex hydrogeological information to a broader audience. The maps clearly demonstrate that the most cost-effective area to develop groundwater is along the Green Line—the 1949 armistice boundary between Israel and the Palestinian West Bank. Any migration of this boundary eastwards will affect the cost and feasibility of developing groundwater within Palestine, making abstraction from the Upper Aquifer impracticable, and increasing the cost of developing the Lower Aquifer. Therefore, the separation wall, which is being constructed to the east of the Armistice Line in Palestinian territory, will significantly reduce the ability of the Palestinians to develop groundwater resources.

  7. A reassessment of the suspended sediment load in the Madeira River basin from the Andes of Peru and Bolivia to the Amazon River in Brazil, based on 10 years of data from the HYBAM monitoring programme

    Science.gov (United States)

    Vauchel, Philippe; Santini, William; Guyot, Jean Loup; Moquet, Jean Sébastien; Martinez, Jean Michel; Espinoza, Jhan Carlo; Baby, Patrice; Fuertes, Oscar; Noriega, Luis; Puita, Oscar; Sondag, Francis; Fraizy, Pascal; Armijos, Elisa; Cochonneau, Gérard; Timouk, Franck; de Oliveira, Eurides; Filizola, Naziano; Molina, Jorge; Ronchail, Josyane

    2017-10-01

    The Madeira River is the second largest tributary of the Amazon River. It contributes approximately 13% of the Amazon River flow and it may contribute up to 50% of its sediment discharge to the Atlantic Ocean. Until now, the suspended sediment load of the Madeira River was not well known and was estimated in a broad range from 240 to 715 Mt yr-1. Since 2002, the HYBAM international network developed a new monitoring programme specially designed to provide more reliable data than in previous intents. It is based on the continuous monitoring of a set of 11 gauging stations in the Madeira River watershed from the Andes piedmont to the confluence with the Amazon River, and discrete sampling of the suspended sediment concentration every 7 or 10 days. This paper presents the results of the suspended sediment data obtained in the Madeira drainage basin during 2002-2011. The Madeira River suspended sediment load is estimated at 430 Mt yr-1 near its confluence with the Amazon River. The average production of the Madeira River Andean catchment is estimated at 640 Mt yr-1 (±30%), the corresponding sediment yield for the Andes is estimated at 3000 t km-2 yr-1 (±30%), and the average denudation rate is estimated at 1.20 mm yr-1 (±30%). Contrary to previous results that had mentioned high sedimentation rates in the Beni River floodplain, we detected no measurable sedimentation process in this part of the basin. On the Mamoré River basin, we observed heavy sediment deposition of approximately 210 Mt yr-1 that seem to confirm previous studies. But while these studies mentioned heavy sedimentation in the floodplain, we showed that sediment deposition occurred mainly in the Andean piedmont and immediate foreland in rivers (Parapeti, Grande, Pirai, Yapacani, Chimoré, Chaparé, Secure, Maniqui) with discharges that are not sufficiently large to transport their sediment load downstream in the lowlands.

  8. Modelling hydrological processes and analysing water-related ecosystem services of Western Siberian lowland basins

    Science.gov (United States)

    Schmalz, Britta; Kiesel, Jens; Kruse, Marion; Pfannerstill, Matthias; Sheludkov, Artyom; Khoroshavin, Vitaliy; Veshkurseva, Tatyana; Müller, Felix; Fohrer, Nicola

    2015-04-01

    For discussing and planning sustainable land management of river basins, stakeholders need suitable information on spatio-temporal patterns of hydrological components and ecosystem services. The ecosystem services concept, i.e., services provided by ecosystems that contribute to human welfare benefits, contributes comprehensive information for sustainable river management. This study shows an approach to use ecohydrological modelling results for quantifying and assessing water-related ecosystem services in three lowland river basins in Western Siberia, a region which is of global significance in terms of carbon sequestration, agricultural production and biodiversity preservation. Using the ecohydrological model SWAT, the three basins Pyschma (16762 km²), Vagai (3348 km²) and Loktinka (373 km²) were modelled following a gradient from the landscape units taiga, pre-taiga to forest steppe. For a correct representation of the Siberian lowland hydrology, the consideration of snow melt and retention of surface runoff as well as the implementation of a second groundwater aquifer was of great importance. Good to satisfying model performances were obtained for the extreme hydrological conditions. The simulated SWAT output variables of different hydrological processes were used as indicators for the two regulating services water flow and erosion regulation. The model results were translated into a relative ecosystem service valuation scale. The resulting ecosystem service maps show different spatial and seasonal patterns. Although the high resolution modelling results are averaged out within the aggregated relative valuation scale, seasonal differences can be depicted: during snowmelt, low relevant regulation can be determined, especially for water flow regulation, but a very high relevant regulation was calculated for the vegetation period during summer and for the winter period. The SWAT model serves as a suitable quantification method for the assessment of water

  9. ORCHILEAK (revision 3875): a new model branch to simulate carbon transfers along the terrestrial-aquatic continuum of the Amazon basin

    Science.gov (United States)

    Lauerwald, Ronny; Regnier, Pierre; Camino-Serrano, Marta; Guenet, Bertrand; Guimberteau, Matthieu; Ducharne, Agnès; Polcher, Jan; Ciais, Philippe

    2017-10-01

    Lateral transfer of carbon (C) from terrestrial ecosystems into the inland water network is an important component of the global C cycle, which sustains a large aquatic CO2 evasion flux fuelled by the decomposition of allochthonous C inputs. Globally, estimates of the total C exports through the terrestrial-aquatic interface range from 1.5 to 2.7 Pg C yr-1 (Cole et al., 2007; Battin et al., 2009; Tranvik et al., 2009), i.e. of the order of 2-5 % of the terrestrial NPP. Earth system models (ESMs) of the climate system ignore these lateral transfers of C, and thus likely overestimate the terrestrial C sink. In this study, we present the implementation of fluvial transport of dissolved organic carbon (DOC) and CO2 into ORCHIDEE (Organising Carbon and Hydrology in Dynamic Ecosystems), the land surface scheme of the Institut Pierre-Simon Laplace ESM. This new model branch, called ORCHILEAK, represents DOC production from canopy and soils, DOC and CO2 leaching from soils to streams, DOC decomposition, and CO2 evasion to the atmosphere during its lateral transport in rivers, as well as exchange with the soil carbon and litter stocks on floodplains and in swamps. We parameterized and validated ORCHILEAK for the Amazon basin, the world's largest river system with regard to discharge and one of the most productive ecosystems in the world. With ORCHILEAK, we are able to reproduce observed terrestrial and aquatic fluxes of DOC and CO2 in the Amazon basin, both in terms of mean values and seasonality. In addition, we are able to resolve the spatio-temporal variability in C fluxes along the canopy-soil-water continuum at high resolution (1°, daily) and to quantify the different terrestrial contributions to the aquatic C fluxes. We simulate that more than two-thirds of the Amazon's fluvial DOC export are contributed by the decomposition of submerged litter. Throughfall DOC fluxes from canopy to ground are about as high as the total DOC inputs to inland waters. The latter

  10. Applying Binary Forecasting Approaches to Induced Seismicity in the Western Canada Sedimentary Basin

    Science.gov (United States)

    Kahue, R.; Shcherbakov, R.

    2016-12-01

    The Western Canada Sedimentary Basin has been chosen as a focus due to an increase in the recent observed seismicity there which is most likely linked to anthropogenic activities related to unconventional oil and gas exploration. Seismicity caused by these types of activities is called induced seismicity. The occurrence of moderate to larger induced earthquakes in areas where critical infrastructure is present can be potentially problematic. Here we use a binary forecast method to analyze past seismicity and well production data in order to quantify future areas of increased seismicity. This method splits the given region into spatial cells. The binary forecast method used here has been suggested in the past to retroactively forecast large earthquakes occurring globally in areas called alarm cells. An alarm cell, or alert zone, is a bin in which there is a higher likelihood for earthquakes to occur based on previous data. The first method utilizes the cumulative Benioff strain, based on earthquakes that had occurred in each bin above a given magnitude over a time interval called the training period. The second method utilizes the cumulative well production data within each bin. Earthquakes that occurred within an alert zone in the retrospective forecast period contribute to the hit rate, while alert zones that did not have an earthquake occur within them in the forecast period contribute to the false alarm rate. In the resulting analysis the hit rate and false alarm rate are determined after optimizing and modifying the initial parameters using the receiver operating characteristic diagram. It is found that when modifying the cell size and threshold magnitude parameters within various training periods, hit and false alarm rates are obtained for specific regions in Western Canada using both recent seismicity and cumulative well production data. Certain areas are thus shown to be more prone to potential larger earthquakes based on both datasets. This has implications

  11. Origin of fine carbonaceous particulate matter in the Western Mediterranean Basin: fossil versus modern sources

    Science.gov (United States)

    Cruz Minguillón, María.; Perron, Nolwenn; Querol, Xavier; Szidat, Sönke; Fahrni, Simon; Wacker, Lukas; Reche, Cristina; Cusack, Michael; Baltensperger, Urs; Prévôt, André S. H.

    2010-05-01

    The present work was carried out in the frame of the international field campaign DAURE (Determination of the sources of atmospheric Aerosols in Urban and Rural Environments in the western Mediterranean). The objective of this campaign is to study the aerosol pollution episodes occurring at regional scale during winter and summer in the Western Mediterranean Basin. As part of this campaign, this work focuses on identifying the origin of fine carbonaceous aerosols. To this end, fine particulate matter (PM1) samples were collected during two different seasons (February-March and July 2009) at two sites: an urban site (Barcelona, NE Spain) and a rural European Supersite for Atmospheric Aerosol Research (Montseny, NE Spain). Subsequently, 14C analyses were carried out on these samples, both in the elemental carbon (EC) fraction and the organic carbon (OC) fraction, in order to distinguish between modern carbonaceous sources (biogenic emissions and biomass burning emissions) and fossil carbonaceous sources (mainly road traffic). Preliminary results from the winter period show that 40% of the OC at Barcelona has a fossil origin whereas at Montseny this percentage is 30%. These values can be considered as unexpected given the nature of the sites. Nevertheless, the absolute concentrations of fossil OC at Barcelona and Montseny differ by a factor of 2 (the first being higher), since the total OC at Montseny is lower than at Barcelona. Further evaluation of results and comparison with other measurements carried out during the campaign are required to better evaluate the origin of the fine carbonaceous matter in the Western Mediterranean Basin. Acknowledgements: Spanish Ministry of Education and Science, for a Postdoctoral Grant awarded to M.C. Minguillón in the frame of Programa Nacional de Movilidad de Recursos Humanos del Plan nacional de I-D+I 2008-2011. Spanish Ministry of Education and Science, for the Acción Complementaria DAURE CGL2007-30502-E/CLI.

  12. The presence of sboA and spaS genes and antimicrobial peptides subtilosin A and subtilin among Bacillus strains of the Amazon basin

    Directory of Open Access Journals (Sweden)

    Renata Voltolini Velho

    2013-01-01

    Full Text Available This report demonstrates the usefulness of PCR for the genes spaS and sboA as a means of identifying Bacillus strains with a potential to produce subtilin and subtilosin A. One collection strain and five Bacillus spp. isolated from aquatic environments in the Amazon basin were screened by PCR using primers for sboA and spaS designed specifically for this study. The sequences of the PCR products showed elevated homology with previously described spaS and sboA genes. Antimicrobial peptides were isolated from culture supernatants and analyzed by mass spectrometry. For all samples, the mass spectra revealed clusters with peaks at m/z 3300-3500 Da, corresponding to subtilosin A, subtilin and isoforms of these peptides. These results suggest that the antimicrobial activity of these strains may be associated with the production of subtilosin A and/or subtilin. The PCR used here was efficient in identifying novel Bacillus strains with the essential genes for producing subtilosin A and subtilin.

  13. Technical note: A hydrological routing scheme for the Ecosystem Demography model (ED2+R) tested in the Tapajós River basin in the Brazilian Amazon

    Science.gov (United States)

    Pereira, Fabio F.; Farinosi, Fabio; Arias, Mauricio E.; Lee, Eunjee; Briscoe, John; Moorcroft, Paul R.

    2017-09-01

    Land surface models are excellent tools for studying how climate change and land use affect surface hydrology. However, in order to assess the impacts of Earth processes on river flows, simulated changes in runoff need to be routed through the landscape. In this technical note, we describe the integration of the Ecosystem Demography (ED2) model with a hydrological routing scheme. The purpose of the study was to create a tool capable of incorporating to hydrological predictions the terrestrial ecosystem responses to climate, carbon dioxide, and land-use change, as simulated with terrestrial biosphere models. The resulting ED2+R model calculates the lateral routing of surface and subsurface runoff resulting from the terrestrial biosphere models' vertical water balance in order to determine spatiotemporal patterns of river flows within the simulated region. We evaluated the ED2+R model in the Tapajós, a 476 674 km2 river basin in the southeastern Amazon, Brazil. The results showed that the integration of ED2 with the lateral routing scheme results in an adequate representation (Nash-Sutcliffe efficiency up to 0.76, Kling-Gupta efficiency up to 0.86, Pearson's R up to 0.88, and volume ratio up to 1.06) of daily to decadal river flow dynamics in the Tapajós. These results are a consistent step forward with respect to the no river representation common among terrestrial biosphere models, such as the initial version of ED2.

  14. Manganese and Mercury Levels in Water, Sediments, and Children Living Near Gold-Mining Areas of the Nangaritza River Basin, Ecuadorian Amazon.

    Science.gov (United States)

    González-Merizalde, Max V; Menezes-Filho, José A; Cruz-Erazo, Claudia Teresa; Bermeo-Flores, Santos Amable; Sánchez-Castillo, María Obdulia; Hernández-Bonilla, David; Mora, Abrahan

    2016-08-01

    Artisanal and small-scale gold-mining activities performed in mountain areas of the Southern Ecuadorian Amazon have incorporated several heavy metals into the aquatic systems, thus increasing the risk of exposure in populations living in adjacent zones. Therefore, the objective of this study was to evaluate the contamination levels of mercury (Hg) and manganese (Mn) in several rivers of the Nangaritza River basin and assess the exposure in school-aged children residing near the gold-mining zones. River water and sediment samples were collected from a highly contaminated (HEx) and a moderately contaminated (MEx) zones. Hair Mn (MnH) and urinary Hg (HgU) levels were determined in school-aged children living in both zones. High concentrations of dissolved Mn were found in river waters of the HEx zone (between 2660 and 3990 µg l(-1)); however, Hg levels, in general, were lower than the detection limit (DL; gold-mining activities can not only produce mercurial contamination, that can also release other heavy metals (such as Mn) that may pose a risk to human health.

  15. Abbreviated larval development of Macrobrachium inpa Kensley and Walker, 1982 (Crustacea: Decapoda: Palaemonidae from an Amazon Basin forest stream, Brazil, reared in the laboratory

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    Célio Magalhães

    Full Text Available Abstract This paper brings the description and illustrations of the abbreviated larval development of the Amazonian freshwater palaemonid shrimp, Macrobrachium inpa Kensley and Walker, 1982. The study was based on ovigerous females (mean total body length of 27.0 ± 1.64 mm collected in a small forest stream in the Reserva Florestal Ducke, near Manaus, Brazil, of which four released their larvae in the laboratory. The females carried 8 to 19 eliptical (2.39 ± 0.10 X 1.67 ± 0.08 mm, yolk-rich eggs. The larval period consists of three benthic, lecithotrophic larval stages, and lasts 10-11 days. The newly-hatched larvae bear very advanced morphological features such as antenna with several marginal plumose seta on scaphocerite and long, multi-articulated flagellum; fully developed, functional uniramous pereiopods 3-5 (walking legs and biramous pleopods. The morphology of the carapace, all appendages of the cephalothorax and pleon, and the tail fan are described in detail and illustrated. The larval form was considered to be a decapodid because of the benthic behavior and due to the fact that functional walking legs and pleopods are the main structures for displacement and propulsion. The larval development of M. inpa is compared with those of the so-called "continental" group of the caridean shrimps from the Amazon River basin.

  16. 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 reverse-sinistral structures. Plate kinematics may play a role in Andean basin evolution, with deformation influenced by major preexisting faults that dictated paleogeographic

  17. Biological behavior of Trypanosoma cruzi stocks obtained from the State of Amazonas, Western Brazilian Amazon, in mice.

    Science.gov (United States)

    Monteiro, Wuelton Marcelo; Magalhães, Laylah Kelre Costa; Oliveira, Josué Costa; Guerra, Jorge Augusto de Oliveira; Silveira, Henrique; Ferreira, Luiz Carlos de Lima; Toledo, Max Jean de Ornelas; Barbosa, Maria das Graças Vale

    2012-01-01

    The biological diversity of circulating Trypanosoma cruzi stocks in the Amazon region most likely plays an important role in the peculiar clinic-epidemiological features of Chagas disease in this area. Seven stocks of T. cruzi were recently isolated in the State of Amazonas, Brazil, from humans, wild mammals, and triatomines. They belonged to the TcI and Z3 genotypes and were biologically characterized in Swiss mice. Parasitological and histopathological parameters were determined. Four stocks did not promote patent parasitemia in mice. Three stocks produced low parasitemia, long pre-patent periods, and a patent period of 1 day or oscillating parasitemia. Maximum parasitemia ranged from 1,400 to 2,800 trypomastigotes/0.1 mL blood. Mice inoculated with the T. cruzi stocks studied showed low positivity during fresh blood examinations, ranging from 0% to 28.6%. In hemoculture, positivity ranged from 0% to 100%. Heart tissue parasitism was observed in mice inoculated with stocks AM49 and AM61. Stock AM49 triggered a moderate inflammatory process in heart tissue. A mild inflammatory process was observed in heart tissue for stocks AM28, AM38, AM61, and AM69. An inflammatory process was frequently observed in skeletal muscle. Examinations of brain tissue revealed inflammatory foci and gliosis in mice inoculated with stock AM49. Biological and histopathological characterization allowed us to demonstrate the low infectivity and virulence of T. cruzi stocks isolated from the State of Amazonas.

  18. Madagascar's escape from Africa: A high-resolution plate reconstruction for the Western Somali Basin and implications for supercontinent dispersal

    Science.gov (United States)

    Phethean, Jordan J. J.; Kalnins, Lara M.; van Hunen, Jeroen; Biffi, Paolo G.; Davies, Richard J.; McCaffrey, Ken J. W.

    2016-12-01

    Accurate reconstructions of the dispersal of supercontinent blocks are essential for testing continental breakup models. Here, we provide a new plate tectonic reconstruction of the opening of the Western Somali Basin during the breakup of East and West Gondwana. The model is constrained by a new comprehensive set of spreading lineaments, detected in this heavily sedimented basin using a novel technique based on directional derivatives of free-air gravity anomalies. Vertical gravity gradient and free-air gravity anomaly maps also enable the detection of extinct mid-ocean ridge segments, which can be directly compared to several previous ocean magnetic anomaly interpretations of the Western Somali Basin. The best matching interpretations have basin symmetry around the M0 anomaly; these are then used to temporally constrain our plate tectonic reconstruction. The reconstruction supports a tight fit for Gondwana fragments prior to breakup, and predicts that the continent-ocean transform margin lies along the Rovuma Basin, not along the Davie Fracture Zone (DFZ) as commonly thought. According to our reconstruction, the DFZ represents a major ocean-ocean fracture zone formed by the coalescence of several smaller fracture zones during evolving plate motions as Madagascar drifted southwards, and offshore Tanzania is an obliquely rifted, rather than transform, margin. New seismic reflection evidence for oceanic crust inboard of the DFZ strongly supports these conclusions. Our results provide important new constraints on the still enigmatic driving mechanism of continental rifting, the nature of the lithosphere in the Western Somali Basin, and its resource potential.

  19. A Metagenomic Perspective on Changes to Nutrient-cycling Genes Following Forest-to-agriculture Conversion in the Amazon Basin

    Science.gov (United States)

    Meyer, K. M.; Womack, A. M.; Rodrigues, J.; Nüsslein, K.; Bohannan, B. J. M.

    2014-12-01

    Forest-to-agriculture conversion has been shown to alter nutrient cycling and the community composition of soil microorganisms. However, few studies have looked simultaneously at how the abundance, composition, and diversity of microbial genes involved in nutrient cycling change with conversion. We used shotgun metagenomic sequencing to analyze soil from primary rainforest and converted cattle pasture sampled at the Fazenda Nova Vida in Rondônia, Brazil. The diversity, richness, and evenness of nutrient cycling genes were significantly higher in the pasture, and the composition of nutrient cycling communities differed significantly between land use types. These results largely mirror taxonomic shifts following Amazon rainforest conversion, which tends to increase diversity, richness, and evenness of soil microbial communities. The abundance of genes related to N cycling and methane flux differed between land use types. Methanotrophy genes decreased in abundance in the pasture, whereas methanogenesis genes were not significantly different between land use types. These changes could underlie the commonly observed shift from methane sink to source following forest-to-agriculture conversion. Multiple genes in the nitrogen cycle also differed with land use, including genes related to N-fixation and ammonification. Metagenomics provides a unique perspective on the consequences of land use change on microbial community structure and function.

  20. SOCIAL ORGANIZATION BASED ON CHAIN-NETWORK LOGIC TO PROMOTE THE EXPLORATION OF NATIVE AÇAÍ IN WESTERN BRAZILIAN AMAZON.

    Directory of Open Access Journals (Sweden)

    Mariluce Paes-de-Souza

    2013-05-01

    Full Text Available The present paper has the objective to expose a proposition of organization within a chain and network logic, aiming to potentiate the extraction of the Native Açaí Berry at the Western Brazilian Amazon rainforest. This exploratory study involves the municipalities of Porto Velho, Guajará-Mirim and Machadinho D’Oeste, at the Brazilian state of Rondônia, with primary data originating mostly from conservation areas at the lower Madeira River region. As a result, it was possible to infer that from the native Açai Berry, derives food, pharmaceuticals and cosmetics, for both local consumption and international markets. It was found that beyond Açai Berry plantations availability, the lower Madeira River provides better transport logistic, consumer market and greater possibility of interaction with middleman than most Açai production areas. As a conclusion, it is made a proposition of an organizational arrangement to strengthen the extrativist productive chain of the Native Açaí Berry, based on the network and chain logic, oriented towards an organization based upon social organizations, manufacturing regularization and marketing.

  1. Serological survey for Chagas disease in the rural areas of Manaus, Coari, and Tefé in the Western Brazilian Amazon

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    Belisa Maria Lopes Magalhães

    2011-12-01

    Full Text Available INTRODUCTION: Deforestation, uncontrolled forest, human population migration from endemic areas, and the large number of reservoirs and wild vectors naturally infected by Trypanosoma cruzi promote the endemicity of Chagas disease in the Amazon region. METHODS: We conducted an initial serological survey (ELISA in a sample of 1,263 persons; 1,095 (86.7% were natives of the State of Amazonas, 666 (52.7% were male, and 948 (75.1% were over 20 years old. Serum samples that were found to be reactive, indeterminate, or inconclusive by indirect immunofluorescence (IFI or positive with low titer by IFA were tested by Western blot (WB. Serologically confirmed patients (WB were evaluated in terms of epidemiological, clinical, ECG, and echocardiography characteristics. RESULTS: Fifteen patients had serologically confirmed T. cruzi infection, and 12 of them were autochthonous to the state of Amazonas, for an overall seroprevalence of 1.2% and 0.9% for the state of Amazonas. Five of the 15 cases were males, and the average age was 47 years old; most were farmers with low education. One patient who was not autochthonous, having originated from Alagoas, showed right bundle branch block, bundle branch block, and anterosuperior left ventricular systolic dysfunction with an ejection fraction of 54%. CONCLUSIONS: The results of this study ratify the importance of monitoring CD cases in Amazonia, particularly in the state of Amazonas.

  2. Serological survey for Chagas disease in the rural areas of Manaus, Coari, and Tefé in the Western Brazilian Amazon.

    Science.gov (United States)

    Magalhães, Belisa Maria Lopes; Coelho, Leíla Ines Aguiar Raposo Câmara; Maciel, Marcel Gonçalves; Ferreira, João Marcos Benfica Barbosa; Umezawa, Eufrozina Setsu; Coura, José Rodrigues; Guerra, Jorge Augusto de Oliveira; Barbosa, Maria das Graças Vale

    2011-01-01

    Deforestation, uncontrolled forest, human population migration from endemic areas, and the large number of reservoirs and wild vectors naturally infected by Trypanosoma cruzi promote the endemicity of Chagas disease in the Amazon region. We conducted an initial serological survey (ELISA) in a sample of 1,263 persons; 1,095 (86.7%) were natives of the State of Amazonas, 666 (52.7%) were male, and 948 (75.1%) were over 20 years old. Serum samples that were found to be reactive, indeterminate, or inconclusive by indirect immunofluorescence (IFI) or positive with low titer by IFA were tested by Western blot (WB). Serologically confirmed patients (WB) were evaluated in terms of epidemiological, clinical, ECG, and echocardiography characteristics. Fifteen patients had serologically confirmed T. cruzi infection, and 12 of them were autochthonous to the state of Amazonas, for an overall seroprevalence of 1.2% and 0.9% for the state of Amazonas. Five of the 15 cases were males, and the average age was 47 years old; most were farmers with low education. One patient who was not autochthonous, having originated from Alagoas, showed right bundle branch block, bundle branch block, and anterosuperior left ventricular systolic dysfunction with an ejection fraction of 54%. The results of this study ratify the importance of monitoring CD cases in Amazonia, particularly in the state of Amazonas.

  3. Evaluation of Helicobacter pylory colonization by serologic test (IgG) and dyspepsia in volunteers from the countryside of Monte Negro, in the Brazilian western Amazon region.

    Science.gov (United States)

    Ribeiro, Rafael Bernardon; Martins, Herlon Saraiva; Dos Santos, Vera Aparecida; El Khouri, Marcelo; Duarte, Leandro Savoy; Burattini, Marcelo Nascimento; Cordeiro, Quirino; Camargo, Luiz Marcelo Aranha; Corbett, Carlos Eduardo Pereira

    2010-01-01

    The present study intended to analyze the seroprevalence of Helicobacter pylori, IgG, and its relation to dyspepsia in a population from the western Amazon region. During the "Projeto Bandeira Científica", a University of São Paulo Medical School program, in Monte Negro's rural areas, state of Rondônia, 266 blood samples were collected from volunteers. The material was tested for IgG antibodies anti-Helicobacter pylori by ELISA method and the participants were also interviewed on dyspepsia, hygiene and social aspects. Participants aged between five and 81 years old (34 years on average), 149 (56%) were female and 117 (44%) male. We found 210 (78.9%) positive, 50 (18.8%) negative and six (2.3%) undetermined samples. Dyspeptic complaints were found in 226 cases (85.2%). There was no statistical association between dyspepsia and positive serology for H. pylori. We concluded that the seroprevalence in all age categories is similar to results found in other studies conducted in developing countries, including those from Brazil. On the other hand, the seroprevalence found in Monte Negro was higher than that reported in developed countries. As expected, there was a progressive increase in the positivity for H. pylori in older age groups.

  4. Maternal fish consumption in the nutrition transition of the Amazon Basin: growth of exclusively breastfed infants during the first 5 years.

    Science.gov (United States)

    Marques, Rejane C; Dórea, José Garrofe; Bernardi, José V E; Bastos, Wanderley R; Malm, Olaf

    2008-01-01

    Changes in fish-eating habits due to rapid urbanization in Western Amazon was used as model to investigate whether maternal fish-intake rate impacts on children's weight and height during the first 5 years. The study examined the growth of 82 breastfed children, and maternal fish consumption (hair mercury concentrations, HHg) during pregnancy and lactation. Fish consumption in mothers and children was estimated through HHg. The children were measured and weighed at birth and at 6 (exclusive breastfeeding), 36 and 60 months. Fish consumption rate (HHg) had no significant impact on children's growth at the specified ages (p = 0.35). After 6 months of exclusive breastfeeding, children had the highest proportion of Z-scores -1 SD) for height-for-age (70/82), weight-for-age (74/82) and weight-for-height (74/82). At 5 years, all but one child attained Z-scores >-1. The apparently good nutritional status of subjects is more likely due to a well balanced diet composition than to only one dietary protein source--fish.

  5. Common Era Hydroclimate and Atmospheric Circulation in the Western Mediterranean Basin

    Science.gov (United States)

    Touchan, R.; Anchukaitis, K. J.; Shishov, V. V.; Kherchouche, D.; Slimani, S.; Ilmen, R.; Hasnaoui, F.; Guibal, F.; Camarero, J. J.; Salguero, R. S.; Piermattei, A.; Sesbou, A.; Meko, D. M.; Cook, B. I.; Sabir, M.

    2016-12-01

    Drought phenomenon in the Mediterranean Basin, including North Africa and the western Mediterranean, has an impact on all segments of society and all economic sectors. To understand contemporary patterns and causes of drought in these regions, it is necessary to understand natural climate variability over the Common Era. Here, we use a network of tree-ring proxies spanning up to a millennium to understand and reconstruct both large-scale Atlantic circulation changes and regional hydroclimate. Eighty-five chronologies across the region show a variable but coherent response to winter-spring precipitation mediated by geography and topography. Reconstructions using this network of spatiotemporal drought variability as well as a new reconstruction of the North Atlantic Oscillation put the past, present, and future climate variability of the region into a long-term Common Era context.

  6. Seismic structure of western Mediterranean back-arc basins and rifted margins - constraints from the Algerian-Balearic and Tyrrhenian Basins

    Science.gov (United States)

    Grevemeyer, Ingo; Ranero, Cesar; Sallares, Valenti; Prada, Manel; Booth-Rea, Guillermo; Gallart, Josep; Zitellini, Nevio

    2017-04-01

    The Western Mediterranean Sea is a natural laboratory to study the processes of continental extension, rifting and back-arc spreading in a convergent setting caused by rollback of fragmented subducting oceanic slabs during the latest phase of consumption of the Tethys ocean, leading to rapid extension in areas characterized by a constant convergence of the African and European Plates since Cretaceous time. Opening of the Algerian-Balearic Basin was governed by a southward and westward retreating slab 21 to 18 Myr and 18 to15 Myr ago, respectively. Opening of the Tyrrhenian Basin was controlled by the retreating Calabrian slab 6 to 2 Myr ago. Yet, little is known about the structure of the rifted margins, back-arc extension and spreading. Here we present results from three onshore/offshore seismic refraction and wide-angle lines and two offshore lines sampling passive continental margins of southeastern Spain and to the south of the Balearic promontory and the structure of the Tyrrhenian Basin to the north of Sicily. Seismic refraction and wide-angle data were acquired in the Algerian-Balearc Basin during a cruise of the German research vessel Meteor in September of 2006 and in the Tyrrhenian Sea aboard the Spanish research vessel Sarmiento de Gamboa in July of 2015. All profiles sampled both continental crust of the margins surrounding the basins and extend roughly 100 km into the Algerian-Balearic and the Tyrrhenian Basins, yielding constraints on the nature of the crust covering the seafloor in the basins and adjacent margins. Crust in the Algerian-Balearic basin is roughly 5-6 km thick and the seismic velocity structure mimics normal oceanic crust with the exception that lower crustal velocity is 24 km under SE Spain and the Balearic Islands, displaying typical features and structure of continental crust. Offshore Sicily, continental crust reaches 22 km. However, the Tyrrhenian Basin indicates a lithosphere with velocities increasing continuously from 3 km/s to

  7. Geographical differences in cancer incidence in the Amazon basin of Ecuador in relation to residence near oil fields.

    Science.gov (United States)

    Hurtig, Anna-Karin; San Sebastián, Miguel

    2002-10-01

    Since 1972, oil companies have extracted more than 2 billion barrels of crude oil from the Ecuadorian Amazon, releasing billions of gallons of untreated wastes and oil directly into the environment. This study aimed to determine if there was any difference in overall and specific cancer incidence rates between populations living in proximity to oil fields and those who live in areas free from oil exploitation. Cancer cases from the provinces of Sucumbios, Orellana, Napo and Pastaza during the period 1985-1998 were included in the study. The exposed population was defined as those living in a county (n = 4) where oil exploitation had been ongoing for a minimum of 20 years up to the date of the study. Non-exposed counties were identified as those (n = 11) without oil development activities. Relative risks (RR) along with 95% CI were calculated for men and women as ratios of the age-adjusted incidence rates in the exposed versus non-exposed group. The RR of all cancer sites combined was significantly elevated in both men and women in exposed counties. Significantly elevated RR were observed for cancers of the stomach, rectum, skin melanoma, soft tissue and kidney in men and for cancers of the cervix and lymph nodes in women. An increase in haematopoietic cancers was also observed in the population under 10 years in the exposed counties in both males and females. Study results are compatible with a relationship between cancer incidence and living in proximity to oil fields. An environmental monitoring and cancer surveillance system in the area is recommended.

  8. Application of the European water framework directive in a Western Mediterranean basin (Málaga, Spain)

    Science.gov (United States)

    Carrasco, F.; Sánchez, D.; Vadillo, I.; Andreo, B.; Martínez, C.; Fernández, L.

    2008-04-01

    The water framework directive (WFD) is applied within the Guadalhorce river basin, a Western Mediterranean basin in the Málaga province (South Spain). Criteria defining different surface and groundwater bodies are described. The basic hydrographic network is constituted of low-mountain and low-altitude Mediterranean mineralized rivers. Heavily modified surface water bodies correspond (1) to areas where dams regulate the main watercourses, (2) to areas downstream of reservoirs, where river flow is reduced, and (3) to the coastal sector of the river where artificial channelling has caused morphological variations. Groundwater bodies are related to carbonate and porous aquifers and, locally, to aquifers influenced by dissolution of evaporites. The main impacts to water bodies are irrigated lands and livestock farming. There are also point sources of pollution, such as wastewater, landfills, golf courses, industrial zones, quarries and petrol stations. In addition, groundwater is frequently pumped for human supply and irrigation. Qualitative status of groundwater bodies was done by chemical analysis of samples from a monitoring network and the quantitative status by examining variations in piezometric levels. Both revealed the existence of water bodies at risk of not meeting the environmental objectives of the WFD. The main indicators of pollution are nitrates related to agricultural activities, and total organic carbon (TOC), PO{4/3-} and NH{4/+} in relation to wastewater.

  9. Organic walled dinoflagellate cysts from the Tarim Basin, western China: Implications for the retreat of the Paratethys Sea

    NARCIS (Netherlands)

    Grothe, A.; Houben, A.J.P.; Bosboom, R.E.; Dupont-Nivet, G.; Brinkhuis, H.

    2011-01-01

    Paleogene sediments of the Tarim basin in western China hold the easternmost extent of the Paratethys Sea, an epicontinental sea that covered a large part of Eurasia and probably extended to the Mediterranean Tethys in the west. The late Cretaceous and Paleogene sedimentary record of the

  10. Overpressure generation and episodic dewatering in the Delaware basin, western Texas: The dual nature of a fault zone

    Science.gov (United States)

    Hansom, J.; Lee, M.; Wolf, L. W.; Kosuwan, T.

    2005-05-01

    This study combines numerical modeling techniques with field data to investigate overpressure development and episodic dewatering processes in the Delaware Basin and the Central Basin Platform (CBP). Low-permeability shales in the eastern Delaware Basin are characterized by elevated pore fluid pressures that are much greater than hydrostatic pressures. Observed geophysical anomalies such as low resistivity, high conductivity, and high seismic transit time are consistent with the presence of fluid-filled, fractured and mechanically weak rocks in the eastern Delaware Basin. Our new geophysical analyses also indicate that the overpressures likely extend further into the shallower western basin in Culberson County near the sulfur mineralization area. The predicted present-day gas window is located within the overpressure zone, suggesting that overpressure may be maintained by active oil-to-gas conversion. A basin hydrology model Basin2 is modified to evaluate the pore pressure increases by oil-gas conversion from the equation of state (EOS) for the CH4-CO2-H2O system. Our modeling shows that source beds in CBP have been rather shallowly buried and did not become thermally mature to generate gas directly. Overpressure and episodic dewatering processes appear to be the most plausible mechanism to move deep-basin hydrocarbons eastward into the CBP and westward into the shallow margin of the Delaware Basin. The model of long-distance fluid migration from the eastern Delaware across the fault zone into the CBP is supported by the geochemical similarities of oils from the two basins. A model that invokes episodic release of overpressured fluids by hydrofracturing processes can simultaneously provide mechanisms for achieving transient overpressure preservation and substantial, episodic fluid movement. The episodic dewatering through hydrofracturing processes thus can better explain the observed overpressure preservation, long-distance fluid migration, and related

  11. LBA-ECO CD-01 Meteorological Data, Tapajos and Amazon Rivers, Santarem, Brazil: 2001

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains meteorological data collected around the confluence of the Tapajos River with the Amazon River in the Amazon Basin near Santarem, Brazil, in...

  12. Scale Invariant Power Laws Capture the 3-D Coupling Between Water, Energy and Carbon Budgets Across River Basins of Increasing Horton-Strahler Orders in the Andes-Amazon System

    Science.gov (United States)

    Poveda, G.; Zapata, A. F.

    2016-12-01

    The Andes-Amazon system exhibits complex interactions and feedbacks between hydrological, ecological, biogeochemical and climatic factors in a broad range of temporal and spatial scales. We aim to understand the coupling existing between water, energy and carbon budgets in the Andes-Amazon system, by performing a systematic study of the system for river basins of increasing Horton-Strahler orders, from the headwaters of the Amazon River basin along the Andes (order ω=1 river sub-basins) to the low-lying larger river sub-basins (order ω=10). To that end, this works introduces a 3-D generalization of the Budyko framework that aims to link the water, energy, and Carbon budgets in river basins. The newly proposed 3-D non-dimensional space is defined by: (1) the ratio between long-term mean values of Actual Evapotranspiration (AET) and Precipitation (P), α=AET/P, representing the water balance; (2) the ratio between AET and Potential Evapotranspiration (PET), β=AET/PET, representing the energy balance; and (3) the ratio between AET and Aboveground Net Primary Productivity, δ=AET/ANPP, representing the carbon budget. We use a 3" Digital Elevation Model (DEM), which allows defining river basins with Horton-Strahler orders from 1 to 10. The long-term water, energy, and carbon budgets are estimated for increasing values of the Horton-Strahler orders during the period 1987-2007. Data sets pertaining to the water balance come from ORE-HYBAM, potential evapotranspiration (PET) from GLEAM (Global Land-surface Evaporation: the Amsterdam Methodology). Data for the energy budget are from the Surface Radiation Budget (SRB). Data for the Carbon budget (annual mean net primary productivity, ANPP, gross primary productivity, GPP, and respiration rates, Rr, come from AMAZALERT and ORCHEDEE (Organizing Carbon and Hydrology In Dynamic EcosystEms), as well as from Flux Tower Data and the LBA project. Our results show that scale invariant power-laws emerge to capture the three 2-D

  13. Seismic and Gravity Investigations of the Western Espanola Basin, Rio Grande Rift, New Mexico

    Science.gov (United States)

    Braile, L. W.; Coldren, B. G.; Baca, A.; Fontana, J.; Olheiser, M.; Ziff, M.; Keske, A.; Rhode, A.; Martin-Short, R.; Allen, W.; Denton, K. M.; Harper, C.; Baldridge, W.; Biehler, S.; Ferguson, J. F.; McPhee, D.; Snelson, C. M.

    2013-12-01

    The SAGE (Summer of Applied Geophysical Experience) program collected new seismic, gravity, electromagnetic and down-hole temperature data in 2013 in the western Espanola basin of the Rio Grande rift area of northern New Mexico. The location, about 25 km NW of Santa Fe, has been identified as a potential geothermal resources area based on relatively high temperature gradients in drill holes. The SAGE 2013 data collection was part of an integrated geophysical study of the area initiated in 2011. Seismic data consisted of a 4.8 km W to E profile (120 three-component stations in four overlapping deployments, 20 m station spacing, using a Vibroseis source - 20 m spacing for reflection VPs; 800 m spacing for refraction VPs) with both refraction and CMP reflection coverage. About 55,000 seismograms were recorded. The surface conditions (dry unconsolidated sediments) increased surface wave energy and limited the signal-to-noise level of the refraction and reflection arrivals. Utilizing longer source-receiver offsets improved the shot-gather record sections by emphasizing wider angle reflections which are very strong and coherent. The refraction data were modeled with first arrival travel time methods. The reflection data were processed to produce a CMP stacked record section. Strong reflectors from basin-filling sedimentary rocks (mostly Tertiary in age) are visible above reflections from a thin section of Paleozoic rocks and the basement. The lower reflections have an apparent dip to the west of about 12 degrees. Eighty-one new gravity measurements (detailed data at 200 m spacing along the seismic profile, and regional stations) were collected and combined with existing regional data for modeling. Interpretation of the seismic and gravity data was aided by refraction velocities, the existence of a nearby regional seismic reflection profile from industry, and lithologies and well-logs from a deep well. The sedimentary basin interpreted from the seismic and gravity data

  14. Hydrologic benchmarking of meteorological drought indices at interannual to climate change timescales: a case study over the Amazon and Mississippi river basins

    Science.gov (United States)

    Joetzjer, E.; Douville, H.; Delire, C.; Ciais, P.; Decharme, B.; Tyteca, S.

    2013-12-01

    Widely used metrics of drought are still derived solely from analyses of meteorological variables such as precipitation and temperature. While drought is generally a consequence of atmospheric anomalies, the impacts to society are more directly related to hydrologic conditions. The present study uses a standardized runoff index (SRI) as a proxy for river discharge and as a benchmark for various meteorological drought indices (scPDSI, SPI, SPEI_th, and SPEI_hg respectively). Only 12-month duration droughts are considered in order to allow a direct (no river routing) comparison between meteorological anomalies and their hydrological counterpart. The analysis is conducted over the Mississippi and Amazon river basins, which provide two contrasted test beds for evaluating drought indices at both interannual (using detrended data) and climate change (using raw data) timescales. Looking first at observations over the second half of the 20th century, the simple SPI based solely on precipitation is no less suitable than more sophisticated meteorological drought indices at detecting interannual SRI variations. Using the detrended runoff and meteorological outputs of a five-member single model ensemble of historical and 21th century climate simulations leads to the same conclusion. Looking at the 21st century projections, the response of the areal fraction in drought to global warming is shown to be strongly metric dependent and potentially overestimated by the drought indices which account for temperature variations. These results suggest that empirical meteorological drought indices should be considered with great caution in a warming climate and that more physical water balance models are needed to account for the impact of the anthropogenic radiative forcings on hydrological droughts.

  15. Adolescent pregnancies and girls' sexual and reproductive rights in the amazon basin of Ecuador: an analysis of providers' and policy makers' discourses

    Directory of Open Access Journals (Sweden)

    Sebastian Miguel

    2010-06-01

    Full Text Available Abstract Background Adolescent pregnancies are a common phenomenon that can have both positive and negative consequences. The rights framework allows us to explore adolescent pregnancies not just as isolated events, but in relation to girls' sexual and reproductive freedom and their entitlement to a system of health protection that includes both health services and the so called social determinants of health. The aim of this study was to explore policy makers' and service providers' discourses concerning adolescent pregnancies, and discuss the consequences that those discourses have for the exercise of girls' sexual and reproductive rights' in the province of Orellana, located in the amazon basin of Ecuador. Methods We held six focus-group discussions and eleven in-depth interviews with 41 Orellana's service providers and policy makers. Interviews were transcribed and analyzed using discourse analysis, specifically looking for interpretative repertoires. Results Four interpretative repertoires emerged from the interviews. The first repertoire identified was "sex is not for fun" and reflected a moralistic construction of girls' sexual and reproductive health that emphasized abstinence, and sent contradictory messages regarding contraceptive use. The second repertoire -"gendered sexuality and parenthood"-constructed women as sexually uninterested and responsible mothers, while men were constructed as sexually driven and unreliable. The third repertoire was "professionalizing adolescent pregnancies" and lead to patronizing attitudes towards adolescents and disregard of the importance of non-medical expertise. The final repertoire -"idealization of traditional family"-constructed family as the proper space for the raising of adolescents while at the same time acknowledging that sexual abuse and violence within families was common. Conclusions Providers' and policy makers' repertoires determined the areas that the array of sexual and reproductive

  16. Edaphic, structural and physiological contrasts across Amazon Basin forest–savanna ecotones suggest a role for potassium as a key modulator of tropical woody vegetation structure and function

    Directory of Open Access Journals (Sweden)

    J. Lloyd

    2015-11-01

    C / N ratios than nearby forest plots. These soil differences were also reflected in canopy averaged leaf traits with savanna trees typically having higher leaf mass per unit area but lower mass-based nitrogen (Nm and potassium (Km. Both Nm and Km also increased with declining mean annual precipitation (PA, but most area-based leaf traits such as leaf photosynthetic capacity showed no systematic variation with PA or vegetation type. Despite this invariance, when taken in conjunction with other measures such as mean canopy height, area-based soil exchangeable potassium content, [K]sa , proved to be an excellent predictor of several photosynthetic properties (including 13C isotope discrimination. Moreover, when considered in a multivariate context with PA and soil plant available water storage capacity (θP as covariates, [K]sa also proved to be an excellent predictor of stand-level canopy area, providing drastically improved fits as compared to models considering just PA and/or θP. Neither calcium, nor magnesium, nor soil pH could substitute for potassium when tested as alternative model predictors (ΔAIC > 10. Nor for any model could simple soil texture metrics such as sand or clay content substitute for either [K]sa or θP. Taken in conjunction with recent work in Africa and the forests of the Amazon Basin, this suggests – in combination with some newly conceptualised interacting effects of PA and θP also presented here – a critical role for potassium as a modulator of tropical vegetation structure and function.

  17. Optical and physical properties of aerosols in the boundary layer and free troposphere over the Amazon Basin during the biomass burning season

    Directory of Open Access Journals (Sweden)

    D. Chand

    2006-01-01

    Full Text Available As part of the Large Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke, Aerosols, Clouds, Rainfall and Climate (LBA-SMOCC campaign, detailed surface and airborne aerosol measurements were performed over the Amazon Basin during the dry to wet season from 16 September to 14 November 2002. Optical and physical properties of aerosols at the surface, and in the boundary layer (BL and free troposphere (FT during the dry season are discussed in this article. Carbon monoxide (CO is used as a tracer for biomass burning emissions. At the surface, good correlation among the light scattering coefficient (σs at 545 nm, PM2.5, and CO indicates that biomass burning is the main source of aerosols. Accumulation of haze during some of the large-scale biomass burning events led to high PM2.5 (225 μg m−3, σs (1435 Mm−1, aerosol optical depth at 500 nm (3.0, and CO (3000 ppb. A few rainy episodes reduced the PM2.5, number concentration (CN and CO concentration by two orders of magnitude. The correlation analysis between σs and aerosol optical thickness shows that most of the optically active aerosols are confined to a layer with a scale height of 1617 m during the burning season. This is confirmed by aircraft profiles. The average mass scattering and absorption efficiencies (545 nm for small particles (diameter Dp2 g−1, respectively, when relating the aerosol optical properties to PM2.5 aerosols. The observed mean single scattering albedo (ωo at 545 nm for submicron aerosols at the surface is 0.92±0.02. The light scattering by particles (Δσs/Δ CN increase 2–10 times from the surface to the FT, most probably due to the combined affects of coagulation and condensation.

  18. Implementation of basic quality control tests for malaria medicines in Amazon Basin countries: results for the 2005–2010 period

    Directory of Open Access Journals (Sweden)

    Pribluda Victor S

    2012-06-01

    Full Text Available Abstract Background Ensuring the quality of malaria medicines is crucial in working toward malaria control and eventual elimination. Unlike other validated tests that can assess all critical quality attributes, which is the standard for determining the quality of medicines, basic tests are significantly less expensive, faster, and require less skilled labour; yet, these tests provide reproducible data and information on several critical quality attributes, such as identity, purity, content, and disintegration. Visual and physical inspection also provides valuable information about the manufacturing and the labelling of medicines, and in many cases this inspection is sufficient to detect counterfeit medicines. The Promoting the Quality of Medicines (PQM programme has provided technical assistance to Amazon Malaria Initiative (AMI countries to implement the use of basic tests as a key screening mechanism to assess the quality of malaria medicines available to patients in decentralized regions. Methods Trained personnel from the National Malaria Control Programmes (NMCPs, often in collaboration with country’s Official Medicine Control Laboratory (OMCL, developed country- specific protocols that encompassed sampling methods, sample analysis, and data reporting. Sampling sites were selected based on malaria burden, accessibility, and geographical location. Convenience sampling was performed and countries were recommended to store the sampled medicines under conditions that did not compromise their quality. Basic analytical tests, such as disintegration and thin layer chromatography (TLC, were performed utilizing a portable mini-laboratory. Results Results were originally presented at regional meetings in a non-standardized format that lacked relevant medicines information. However, since 2008 information has been submitted utilizing a template specifically developed by PQM for that purpose. From 2005 to 2010, the quality of 1,663 malaria medicines

  19. Simulation of daily streamflow for 12 river basins in western Iowa using the Precipitation-Runoff Modeling System

    Science.gov (United States)

    Christiansen, Daniel E.; Haj, Adel E.; Risley, John C.

    2017-10-24

    The U.S. Geological Survey, in cooperation with the Iowa Department of Natural Resources, constructed Precipitation-Runoff Modeling System models to estimate daily streamflow for 12 river basins in western Iowa that drain into the Missouri River. The Precipitation-Runoff Modeling System is a deterministic, distributed-parameter, physical-process-based modeling system developed to evaluate the response of streamflow and general drainage basin hydrology to various combinations of climate and land use. Calibration periods for each basin varied depending on the period of record available for daily mean streamflow measurements at U.S. Geological Survey streamflow-gaging stations.A geographic information system tool was used to delineate each basin and estimate initial values for model parameters based on basin physical and geographical features. A U.S. Geological Survey automatic calibration tool that uses a shuffled complex evolution algorithm was used for initial calibration, and then manual modifications were made to parameter values to complete the calibration of each basin model. The main objective of the calibration was to match daily discharge values of simulated streamflow to measured daily discharge values. The Precipitation-Runoff Modeling System model was calibrated at 42 sites located in the 12 river basins in western Iowa.The accuracy of the simulated daily streamflow values at the 42 calibration sites varied by river and by site. The models were satisfactory at 36 of the sites based on statistical results. Unsatisfactory performance at the six other sites can be attributed to several factors: (1) low flow, no flow, and flashy flow conditions in headwater subbasins having a small drainage area; (2) poor representation of the groundwater and storage components of flow within a basin; (3) lack of accounting for basin withdrawals and water use; and (4) limited availability and accuracy of meteorological input data. The Precipitation-Runoff Modeling System

  20. Arboviral diseases in the Western Brazilian Amazon: a perspective and analysis from a tertiary health & research center in Manaus, State of Amazonas.

    Science.gov (United States)

    Mourão, Maria Paula Gomes; Bastos, Michele de Souza; Figueiredo, Regina Maria Pinto de; Gimaque, João Bosco de Lima; Alves, Valquíria do Carmo Rodrigues; Saraiva, Maria das Graças Gomes; Figueiredo, Mário Luis Garcia; Ramasawmy, Rajendranath; Nogueira, Maurício Lacerda; Figueiredo, Luiz Tadeu Moraes

    2015-01-01

    The Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), located in Manaus, the capital of the State of Amazonas (Western Brazilian Amazon), is a pioneering institution in this region regarding the syndromic surveillance of acute febrile illness, including arboviral infections. Based on the data from patients at the FMT-HVD, we have detected recurrent outbreaks in Manaus by the four dengue serotypes in the past 15 years, with increasing severity of the disease. This endemicity has culminated in the simultaneous circulation of all four serotypes in 2011, the first time this has been reported in Brazil. Between 1996 and 2009, 42 cases of yellow fever (YF) were registered in the State of Amazonas, and 71.4% (30/42) were fatal. Since 2010, no cases have been reported. Because the introduction of the yellow fever virus into a large city such as Manaus, which is widely infested by Aedes mosquitoes, may pose a real risk of a yellow fever outbreak, efforts to maintain an appropriate immunization policy for the populace are critical. Manaus has also suffered silent outbreaks of Mayaro and Oropouche fevers lately, most of which were misdiagnosed as dengue fever. The tropical conditions of the State of Amazonas favor the existence of other arboviruses capable of producing human disease. Under this real threat, represented by at least 4 arboviruses producing human infections in Manaus and in other neighboring countries, it is important to develop an efficient public health surveillance strategy, including laboratories that are able to make proper diagnoses of arboviruses.

  1. Arboviral diseases in the Western Brazilian Amazon: a perspective and analysis from a tertiary health & research center in Manaus, State of Amazonas

    Directory of Open Access Journals (Sweden)

    Maria Paula Gomes Mourão

    2015-06-01

    Full Text Available The Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD, located in Manaus, the capital of the State of Amazonas (Western Brazilian Amazon, is a pioneering institution in this region regarding the syndromic surveillance of acute febrile illness, including arboviral infections. Based on the data from patients at the FMT-HVD, we have detected recurrent outbreaks in Manaus by the four dengue serotypes in the past 15 years, with increasing severity of the disease. This endemicity has culminated in the simultaneous circulation of all four serotypes in 2011, the first time this has been reported in Brazil. Between 1996 and 2009, 42 cases of yellow fever (YF were registered in the State of Amazonas, and 71.4% (30/42 were fatal. Since 2010, no cases have been reported. Because the introduction of the yellow fever virus into a large city such as Manaus, which is widely infested by Aedes mosquitoes, may pose a real risk of a yellow fever outbreak, efforts to maintain an appropriate immunization policy for the populace are critical. Manaus has also suffered silent outbreaks of Mayaro and Oropouche fevers lately, most of which were misdiagnosed as dengue fever. The tropical conditions of the State of Amazonas favor the existence of other arboviruses capable of producing human disease. Under this real threat, represented by at least 4 arboviruses producing human infections in Manaus and in other neighboring countries, it is important to develop an efficient public health surveillance strategy, including laboratories that are able to make proper diagnoses of arboviruses.

  2. The Calabrian in the Western Transcaucasian basin (Georgia): Paleomagnetic constraints from the Gurian regional stage

    Science.gov (United States)

    Kirscher, U.; Oms, O.; Bruch, A. A.; Shatilova, I.; Chochishvili, G.; Bachtadse, V.

    2017-03-01

    The precise Eurasian chronostratigraphy of the Neogene-Quaternary period is still hampered by the existence of numerous regional stages often lacking independent and absolute age constraints. Therefore, detailed paleoclimatic reconstructions of areas like the Caucasus are still poorly constrained and the influence of climate variability on faunal interchange between Africa and Eurasia in the late Neogene-Quaternary is still difficult to address. During the last decades, Quaternary sections from western Georgia have produced a wealth of paleoclimatic proxy data. Unfortunately, these sections do not have a robust age control. This is especially true for the Gurian stage which has been vaguely defined as being coeval with the lower Pleistocene on the basis of poorly documented bio- and magnetostratigraphic data. In order to constrain the age of the Gurian stage, a detailed magnetostratigraphic study has been carried out. All major sections with known Gurian sediments in the former Rioni bay (a marine restricted area to the southeast of the Major Caucasus) have been studied. Our results confirm for the first time the strict correlation between the Gurian succession and the Calabrian stage. In addition, our data provides further information on the tectonic setting of the Rioni bay during the Calabrian in this region: (1) in the north, Gurian sediments were unconformably deposited on older Meotian sediments in a piggy back basin, (2) in the south, Gurian sediments are conformably overlying Kujalnician (Plio-Pleistocene) strata, (3) magnetostratigraphic correlation among sections indicate drastic changes in sediment accumulation rates within the basin, (4) rock magnetic experiments reveal significant magnetomineralogical differences between Gurian and the underlying Miocene sediments likely documenting a transition related to changes in oxic conditions, supply of terrigenous material and sedimentation rate close to the Miocene-Pliocene boundary. These results provide a

  3. Changes in precipitating snow chemistry with seasonality in the remote Laohugou glacier basin, western Qilian Mountains.

    Science.gov (United States)

    Dong, Zhiwen; Qin, Dahe; Qin, Xiang; Cui, Jianyong; Kang, Shichang

    2017-04-01

    Trace elements in the atmosphere could provide information about regional atmospheric pollution. This study presented a whole year of precipitation observation data regarding the concentrations of trace metals (e.g., Cr, Ni, Cu, Mn, Cd, Mo, Pb, Sb, Ti, and Zn), and a TEM-EDX (transmission electron microscope-energy dispersive X-ray spectrometer) analysis from June 2014 to September 2015 at a remote alpine glacier basin in Northwest China, the Laohugou (LHG) basin (4200 m a.s.l.), to determine the regional scale of atmospheric conditions and chemical processing in the free troposphere in the region. The results of the concentrations of trace metals showed that, although the concentrations generally were lower compared with that of surrounding rural areas (and cities), they showed an obviously higher concentration and higher EFs in winter (DJF) and a relatively lower concentration and lower EFs in summer (JJA) and autumn (SON), implying clearly enhanced winter pollution of the regional atmosphere in Northwest China. The TEM observed residue in precipitation that was mainly composed of types of dust, salt-dust, BC-fly ash-soot, and organic particles in precipitation, which also showed remarked seasonal change, showing an especially high ratio of BC-soot-fly ash particles in winter precipitation compared with that of other seasons (while organic particles were higher in the summer), indicating significant increased anthropogenic particles in the winter atmosphere. The source of increased winter anthropogenic pollutants mainly originated from emissions from coal combustion, e.g., the regional winter heating supply for residents and cement factories in urban and rural regions of Northwest China. Moderate Resolution Imaging Spectroradiometer (MODIS) atmospheric optical depth (AOD) also showed a significant influence of regional atmospheric pollutant emissions over the region in winter. In total, this work indicated that the atmospheric environment in western Qilian

  4. Classification scheme for acid rock drainage detection - the Hamersley Basin, Western Australia

    Science.gov (United States)

    Skrzypek, Grzegorz; Dogramaci, Shawan; McLean, Laura

    2017-04-01

    In arid environment where precipitation and surface water are very limited, groundwater is the most important freshwater resource. For this reasons it is intensively exploited and needs to be managed wisely and protected from pollutants. Acid rock drainage often constitutes a serious risk to groundwater quality, particularly in catchments that are subject to mining, large scale groundwater injection or abstraction. However, assessment of the potential acid rock drainage risk can be challenging, especially in carbonate rich environment, where the decreasing pH that usually accompanies pyrite oxidation, can be masked by the high pH-neutralisation capacity of carbonate minerals. In this study, we analysed 73 surface and groundwater samples from different water bodies and aquifers located in the Hamersley Basin, Western Australia. Although the majority of samples had a neutral pH, there was a large spatial variability in the dissolved sulphate concentrations that ranged from 1 mg/L to 15,000 mg/L. Waters with high dissolved sulphate concentration were found in areas with a high percentage of sulphide minerals (e.g. pyrite) located within the aquifer matrix and were characterised by low δ34SSO4 values (+1.2‰ to +4.6) consistent with signatures of aquifer matrix pyritic rock samples (+1.9‰ to +4.4). It was also found that the SO4 concentrations and acidity levels were not only dependent on δ34SSO4 values and existence of pyrite but also on the presence of carbonate minerals in the aquifer matrix. Based on the results from this study, a classification scheme has been developed for identification of waters impacted by acid rock drainage that also encompasses numerous concomitant geochemical processes that often occur in aqueous systems. The classification uses five proxies: SO4, SO4/Cl, SI of calcite, δ34SSO4 and δ18OSO4 to improve assessment of the contribution that oxidation of sulphide minerals has to overall sulphate ion concentrations, regardless of acidity

  5. Mid-21st century projections of hydroclimate in Western Himalayas and Satluj River basin

    Science.gov (United States)

    Tiwari, Sarita; Kar, Sarat C.; Bhatla, R.

    2018-02-01

    The Himalayan climate system is sensitive to global warming and climate change. Regional hydrology and the downstream water flow in the rivers of Himalayan origin may change due to variations in snow and glacier melt in the region. This study examines the mid-21st century climate projections over western Himalayas from the Coupled Model Intercomparison Project Phase 5 (CMIP5) global climate models under Representative Concentration Pathways (RCP) scenarios (RCP4.5 and RCP8.5). All the global climate models used in the present analysis indicate that the study region would be warmer by mid-century. The temperature trends from all the models studied here are statistically significant at 95% confidence interval. Multi-model ensemble spreads show that there are large differences among the models in their projections of future climate with spread in temperature ranging from about 1.5 °C to 5 °C over various areas of western Himalayas in all the seasons. Spread in precipitation projections lies between 0.3 and 1 mm/day in all the seasons. Major shift in the timing of evaporation maxima and minima is noticed. The GFDL_ESM2G model products have been downscaled to Satluj River basin using the weather research and forecast (WRF) model and impact of climate change on streamflow has been studied. The reduction of precipitation during JJAS is expected to be > 3-6 mm/day in RCP8.5 as compared to present climate. It is expected that precipitation amount shall increase over Satluj basin in future (mid-21st century) The soil and water assessment tool (SWAT) model has been used to simulate the Satluj streamflow for the present and future climate using GFDL_ESM2G precipitation and temperature data as well as the WRF model downscaled data. The computations using the global model data show that total annual discharge from Satluj will be less in future than that in present climate, especially in peak discharge season (JJAS). The SWAT model with downscaled output indicates that during

  6. Hydrological Retrospective of floods and droughts: Case study in the Amazon

    Science.gov (United States)

    Wongchuig Correa, Sly; Cauduro Dias de Paiva, Rodrigo; Carlo Espinoza Villar, Jhan; Collischonn, Walter

    2017-04-01

    Recent studies have reported an increase in intensity and frequency of hydrological extreme events in many regions of the Amazon basin over last decades, these events such as seasonal floods and droughts have originated a significant impact in human and natural systems. Recently, methodologies such as climatic reanalysis are being developed in order to create a coherent register of climatic systems, thus taking this notion, this research efforts to produce a methodology called Hydrological Retrospective (HR), that essentially simulate large rainfall datasets over hydrological models in order to develop a record over past hydrology, enabling the analysis of past floods and droughts. We developed our methodology on the Amazon basin, thus we used eight large precipitation datasets (more than 30 years) through a large scale hydrological and hydrodynamic model (MGB-IPH), after that HR products were validated against several in situ discharge gauges dispersed throughout Amazon basin, given focus in maximum and minimum events. For better HR results according performance metrics, we performed a forecast skill of HR to detect floods and droughts considering in-situ observations. Furthermore, statistical temporal series trend was performed for intensity of seasonal floods and drought in the whole Amazon basin. Results indicate that better HR represented well most past extreme events registered by in-situ observed data and also showed coherent with many events cited by literature, thus we consider viable to use some large precipitation datasets as climatic reanalysis mainly based on land surface component and datasets based in merged products for represent past regional hydrology and seasonal hydrological extreme events. On the other hand, an increase trend of intensity was realized for maximum annual discharges (related to floods) in north-western regions and for minimum annual discharges (related to drought) in central-south regions of the Amazon basin, these features were

  7. Manganese carbonates in the Upper Jurassic Georgiev Formation of the Western Siberian marine basin

    Science.gov (United States)

    Eder, Vika G.; Föllmi, Karl B.; Zanin, Yuri N.; Zamirailova, Albina G.

    2018-01-01

    Manganese (Mn) carbonate rocks are a common lithological constituent of the Upper Oxfordian to Lower Tithonian (Volgian) Georgiev Formation of the Western Siberian marine basin (WSMB). The Mn carbonates in the Georgiev Formation are present in the form of massive sediments, stromatolites, and oncolites, and are associated with glauconite and partly also phosphate-rich clay- and siltstones. Unlike most Mn carbonates, they are not directly associated with organic-rich sediments, but occur below an organic-rich succession (Bazhenov Formation). The Mn carbonate occurrences can be traced from the western central area of the WSMB to its center along a distance of at least 750 km. The thickness of the Mn carbonates and their Mn contents becomes reduced in an eastward direction, related to increased detrital input. The geochemical and mineralogical heterogeneity within the Mn carbonates indicates that they were deposited stepwise in a diagenetic regime characterized by steep gradients in Mn, Ca, and Mg. A first step consisted in the replacement of initial sediments within the microbialites during an early diagenetic stage, followed by a second step where massive sediments were transformed into Mn carbonate. During both steps, the decomposition of organic matter was an important source of the newly formed carbonate. During a further step, voids were cemented by Mn carbonates, which are rich in pyrite. This last generation may only have formed once the organic-rich sediments of the overlying Bazhenov Formation were deposited. Accumulation of the Mn carbonates in the Upper Jurassic WSMB was controlled by the proximity of Mn-enriched parent rocks, likely in the Ural, which were subjected to intense geochemical weathering during the Late Jurassic.

  8. Eddy covariance fluxes of the NO-O3-NO2 triad above the forest canopy at the ATTO Site in the Amazon Basin

    Science.gov (United States)

    Tsokankunku, Anywhere; Wolff, Stefan; Sörgel, Matthias; Berger, Martina; Zelger, Michael; Dlugi, Ralf

    2017-04-01

    Nitrogen monoxide (NO) and nitrogen dioxide (NO2) (denoted together as NOx) determine the abundance of the tropospheric oxidants OH, O3 and NO3 that regulate atmospheric self-cleaning. The three reactive trace gases NO, NO2 and O3 undergo a series of interconnected photochemical reactions and are often referred to as the NO-O3-NO2 triad. Ozone deposition is mainly controlled by stomatal uptake, thus contributes to oxidative stress for the plants. Similarly, nitrogen dioxide from above or below the canopy is deposited to leaves through stomatal uptake. NO emissions from soils contribute to above canopy O3 formation and accelerate OH recycling. Therefore, quantification of the exchange fluxes of these species between the atmosphere and the biosphere are important for atmospheric chemistry and ecosystem research as well. The eddy covariance method is state of the art for direct measurements of ecosystem fluxes of trace gases. Eddy covariance measurements of NOx in pristine environments are rare because of lack of availability of instruments with the required precision to resolve concentrations characteristic of these environments. The Amazon Tall Tower Observatory (ATTO) is located in a pristine rainforest environment in the Amazon basin about 150 km northeast of the city of Manaus. It is the ideal site for studying the biosphere-atmosphere exchange of the NO-O3-NO2 triad, being largely undisturbed by anthropogenic sources. During an intensive measurement campaign in November 2015 at the ATTO site, measurements of NO, NO2 and O3 were carried out at 42 m above ground level on the 80 m walk-up tower with a fast (5 Hz) and sensitive (< 30 ppt) instrument (CLD790SR2, Eco Physics) for NO and NO2 and with 10 Hz for O3 (Enviscope). Additionally, measurements of turbulent and micrometeorological parameters were conducted with a profile of 3-dimensional sonic anemometers and meteorological sensors for temperature, humidity and radiation. Vertical concentration profile

  9. Ground-water quality in the western Snake River basin, Swan Falls to Glenns Ferry, Idaho

    Science.gov (United States)

    Parliman, D.J.

    1983-01-01

    Water-quality data were collected from 92 wells in the western Snake River basin, Swan Falls to Glenns Ferry, Idaho. Current data were compiled with pre-1980 data from 116 wells to define water-quality conditions in major aquifers. Factors affecting water quality are composition of aquifer materials, water temperature, and source of recharge. Mixing of water by interaquifer flow, from confined, hot water aquifers (40 degrees Celsius or greater) with water from cold water aquifers (less than 20 degrees Celsius) occurs along regional complex fault systems, and through partially cased boreholes. Cold water generally contains calcium, magnesium, and bicarbonate plus carbonate ions; hot water generally contains sodium, potassium, and bicarbonate plus carbonate ions. Warm water (between 20 degrees and 40 degrees Celsius) has an intermediate chemical composition resulting from mixing. Ground-water quality is acceptable for most uses, although it locally contains chemical constituents or physical properties that may restrict its use. Effects of thermal water used for irrigation on quality of shallow ground water are inconclusive. Long-term increase in concentrations of several constituents in parts of the study area may be due to effects of land- and water-use activities, such as infiltration of septic-tank effluent. (USGS)

  10. Fractured rock aquifer tests in the Western Siberian Basin, Ozyorsk, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, R.L.; Looney, B.B.; Eddy-Dilek, C.A. [and others

    1997-10-01

    A series of multi-zone pumping tests was conducted in a contaminated fractured rock aquifer in the Western Siberian Basin, Ozyorsk, Russia. The tests were conducted adjacent to the Mishelyak River floodplain in fractured Paleozoic porphyrites, tufts, tuff breccia, and lava typical of the Ural mountain complex. Geophysical logs, borehole photography, core samples, and results from previous borehole contamination studies were used to identify the zones to be tested. A network of three uncased wells was tested using a system of inflatable packers, pressure transducers and data loggers. Seven zones were isolated and monitored in two of the uncased wells. A straddle packer assembly was used to isolate individual zones within the pumping well. Eight constant rate pumping tests were conducted. Results of the testing indicate that shallow groundwater migrates primarily in two intervals that are separated by an interval with low lateral conductivity. The water bearing intervals have moderate to high specific capacities (1.3 and 30 L/min/m). Several processes are responsible for fracturing present in the lower interval. The network of compound fractures produced a complex array of fracture intersections yielding a fractured media with hydraulic behavior similar to porous media. Models used for the analysis of pumping tests in porous media provide a good estimation of the hydraulic response of the lower interval to pumping. Future work will include more complex analysis of the data to determine hydraulic conductivity ellipses.

  11. Evolution of Rotations in the Fish Creek Vallecito Basin, Western Salton Trough, CA

    Science.gov (United States)

    Housen, B. A.; Dorsey, R. J.; Janecke, S. U.; Axen, G. J.

    2006-12-01

    Rocks in the Western Salton Trough region record the history of slip on the transtensional West Salton detachment fault and initiation of younger strike-slip faults in this plate boundary zone. Spatial and temporal patterns of vertical axis rotations as determined by paleomagnetism can be used to provide valuable constraints on the structural-tectonic evolution of this area. Prior work includes the magnetostratigraphy of Plio-Pleistocene sedimentary rocks in the Fish Creek-Vallecito Basin (FCVB) (Opdyke et al., 1977; Johnson et al., 1983), who found that these rocks contain a complete record of geomagnetic field reversals spanning Pliocene-Pleistocene time. Johnson et al. (1983) also concluded that the FCVB had undergone 35° of CW rotation during the past 0.9 Ma. We resampled and reanalyzed their section, and sampled additional sedimentary and plutonic rocks in the Western Salton Trough in order to better document the history of vertical axis rotation recorded by these rocks. Results from 29 sites in the FCVB have well-defined magnetizations with two components. The first removed component in all samples is unblocked between 90 and 220 °C, and the second-removed components are unblocked between 300 and 590 °C. The second-removed components have either normal or reversed polarity. Sites from the Diablo Fm are predominantly reversed and have a mean of D = 204, I = -48.3, k = 37, α95 = 12.7°, N = 5. Sites from the middle of the section (Olla and Tapiado Fms) are predominantly normal and have a mean of D = 8.1, I = 48, k = 32, α95= 8.7°, N = 10. Sites from the upper portion of the section (Hueso Fm) have predominantly reversed polarity with means of D = 179.6, I = -43.4, k = 82, α95 = 10.2°, N = 4. Results from weakly-magnetized and deformed rocks of the La Posta pluton, on the south side of Whale Peak, have well-defined magnetizations with a group mean direction of D = 16.3, I = 37.3, k = 44, α95 = 7.4°, N = 10. The stratigraphic distribution of declination

  12. Real-time measurements of ammonia, acidic trace gases and water-soluble inorganic aerosol species at a rural site in the Amazon Basin

    Directory of Open Access Journals (Sweden)

    I. Trebs

    2004-01-01

    Full Text Available We measured the mixing ratios of ammonia (NH3, nitric acid (HNO3, nitrous acid (HONO, hydrochloric acid (HCl, sulfur dioxide (SO2 and the corresponding water-soluble inorganic aerosol species, ammonium (NH4+, nitrate (NO3-, nitrite (NO2-, chloride (Cl- and sulfate (SO42-, and their diel and seasonal variations at a pasture site in the Amazon Basin (Rondônia, Brazil. This study was conducted within the framework of LBA-SMOCC (Large Scale Biosphere Atmosphere Experiment in Amazonia - Smoke Aerosols, Clouds, Rainfall and Climate: Aerosols from Biomass Burning Perturb Global and Regional Climate. Sampling was performed from 12 September to 14 November 2002, extending from the dry season (extensive biomass burning activity, through the transition period to the wet season (background conditions. Measurements were made continuously using a wet-annular denuder (WAD in combination with a Steam-Jet Aerosol Collector (SJAC followed by suitable on-line analysis. A detailed description and verification of the inlet system for simultaneous sampling of soluble gases and aerosol compounds is presented. Overall measurement uncertainties of the ambient mixing ratios usually remained below 15%. The limit of detection (LOD was determined for each single data point measured during the field experiment. Median LOD values (3σ-definition were ≤0.015ppb for acidic trace gases and aerosol anions and ≤0.118ppb for NH3 and aerosol NH4+. Mixing ratios of acidic trace gases remained below 1ppb throughout the measurement period, while NH3 levels were an order of magnitude higher. Accordingly, mixing ratios of NH4+ exceeded those of other inorganic aerosol contributors by a factor of 4 to 10. During the wet season, mixing ratios decreased by nearly a factor of 3 for all compounds compared to those observed when intensive biomass burning took place. Additionally, N-containing gas and aerosol species featured pronounced diel variations. This is attributed to strong

  13. Spectral light absorption by ambient aerosols influenced by biomass burning in the Amazon Basin I. Comparison and field calibration of absorption measurement techniques

    Science.gov (United States)

    Schmid, O.; Artaxo, P.; Arnott, W. P.; Chand, D.; Gatti, L. V.; Frank, G. P.; Hoffer, A.; Schnaiter, M.; Andreae, M. O.

    2005-09-01

    Spectral aerosol light absorption is an important parameter for the assessment of the radiation budget of the atmosphere. Although on-line measurement techniques for aerosol light absorption, such as the Aethalometer and the Particle Soot Absorption Photometer (PSAP), have been available for two decades, they are limited in accuracy and spectral resolution because of the need to deposit the aerosol on a filter substrate before measurement. Recently, a 7-wavelength (λ) Aethalometer became commercially available, which covers the visible (VIS) to near-infrared (NIR) spectral range (λ=450-950 nm), and laboratory calibration studies improved the degree of confidence in these measurement techniques. However, the applicability of the laboratory calibration factors to ambient conditions has not been investigated thoroughly yet. As part of the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia - SMOke aerosols, Clouds, rainfall and Climate) campaign from September to November 2002 in the Amazon basin we performed an extensive field calibration of a 1-λ PSAP and a 7-λ Aethalometer utilizing a photoacoustic spectrometer (PAS, 532 nm) as reference device. Especially during the dry period of the campaign, the aerosol population was dominated by pyrogenic emissions. The most pronounced artifact of integrating-plate type attenuation techniques is due to multiple scattering effects within the filter matrix. For the PSAP, we essentially confirmed the laboratory calibration factor by Bond (1999). On the other hand, for the Aethalometer we found a multiple scattering enhancement of 5.23 (or 4.55, if corrected for aerosol scattering), which is significantly larger than the factors previously reported (~2). While the exact reason for this discrepancy is unknown, the available data from the present and previous studies suggest aerosol mixing (internal versus external) as a likely cause. While it is well-known that RH may (moderately) affect aerosol absorption, we

  14. Killer Whale (Orcinus orca) Predation on Beaked Whales (Mesoplodon spp.) in the Bremer Sub-Basin, Western Australia

    OpenAIRE

    Wellard, Rebecca; Lightbody, Keith; Fouda, Leila; Blewitt, Michelle; Riggs, David; Erbe, Christine

    2016-01-01

    Observations of killer whales (Orcinus orca) feeding on the remains of beaked whales have been previously documented; however, to date, there has been no published account of killer whales actively preying upon beaked whales. This article describes the first field observations of killer whales interacting with, hunting and preying upon beaked whales (Mesoplodon spp.) on four separate occasions during 2014, 2015 and 2016 in the Bremer Sub-Basin, off the south coast of Western Australia.

  15. Killer Whale (Orcinus orca) Predation on Beaked Whales (Mesoplodon spp.) in the Bremer Sub-Basin, Western Australia.

    Science.gov (United States)

    Wellard, Rebecca; Lightbody, Keith; Fouda, Leila; Blewitt, Michelle; Riggs, David; Erbe, Christine

    2016-01-01

    Observations of killer whales (Orcinus orca) feeding on the remains of beaked whales have been previously documented; however, to date, there has been no published account of killer whales actively preying upon beaked whales. This article describes the first field observations of killer whales interacting with, hunting and preying upon beaked whales (Mesoplodon spp.) on four separate occasions during 2014, 2015 and 2016 in the Bremer Sub-Basin, off the south coast of Western Australia.

  16. Killer Whale (Orcinus orca Predation on Beaked Whales (Mesoplodon spp. in the Bremer Sub-Basin, Western Australia.

    Directory of Open Access Journals (Sweden)

    Rebecca Wellard

    Full Text Available Observations of killer whales (Orcinus orca feeding on the remains of beaked whales have been previously documented; however, to date, there has been no published account of killer whales actively preying upon beaked whales. This article describes the first field observations of killer whales interacting with, hunting and preying upon beaked whales (Mesoplodon spp. on four separate occasions during 2014, 2015 and 2016 in the Bremer Sub-Basin, off the south coast of Western Australia.

  17. Stable Carbon Isotope Enrichment Before Late Miocene and Its Iimplication for Landscape Change in the Amazon Basin

    Science.gov (United States)

    Lee, Y. I.; Kim, D.; Hyeong, K.; Chan Min, Y.

    2016-12-01

    The appearance and development of C4 plants in the Late Miocene is well-established by various lines of evidence including stable carbon isotope data, yet the stable carbon isotope change before the global vegetation change has not been reported. Prior to the C4 plant expansion, the ecosystem may have been composed of C3 plants. Here we present the content and stable carbon isotope record of black carbon (BC) in a 470-cm-long piston core retrieved from the northeastern equatorial Pacific. Although suitable age dating method is lacking for the studied core, correlation of clay mineral composition, BC content, and stable carbon isotope data with a nearby well-studied core (Kim et al., submitted) at the same latitude suggests that the studied core contains sediment older than 15 Ma (330 cm in depth) and possibly back to 25 Ma, much prior to the major diversification of C4 plants. The older sediment was derived from Southern Hemisphere. The δ13C value of BC in the oldest sediment shows a relatively high value ( -22.7 ‰ on average), similar to that of C4 expansion event, and then decreases with time till reaching normal δ13C value of C3-dominated environment (-25.3 ‰ on average) around 13 Ma. This relatively high δ13C value reflects the presence of specific ecosystem, likely Pebas wetland that dominated western Amazonia before 17 Ma, and decreasing δ13C value suggests subsequent gradual development of closed-forest ecosystem. The BC content shows an abrupt increase around 400 cm, suggesting a significant aridity event in South America. Uplift of the North Andean region at 23 Ma seems to be the likely cause of such aridity event. From these observations, we argue that by comparing with the well-studied core data environmental record provided by BC data can be used for approximate age dating of deep-sea core sediment lacking appropriate dating tools, and that carbon isotope data before C4 development event may also provide information about specific regional

  18. Multi-decadal Hydrological Retrospective: Case study of Amazon floods and droughts

    Science.gov (United States)

    Wongchuig Correa, Sly; Paiva, Rodrigo Cauduro Dias de; Espinoza, Jhan Carlo; Collischonn, Walter

    2017-06-01

    Recently developed methodologies such as climate reanalysis make it possible to create a historical record of climate systems. This paper proposes a methodology called Hydrological Retrospective (HR), which essentially simulates large rainfall datasets, using this as input into hydrological models to develop a record of past hydrology, making it possible to analyze past floods and droughts. We developed a methodology for the Amazon basin, where studies have shown an increase in the intensity and frequency of hydrological extreme events in recent decades. We used eight large precipitation datasets (more than 30 years) as input for a large scale hydrological and hydrodynamic model (MGB-IPH). HR products were then validated against several in situ discharge gauges controlling the main Amazon sub-basins, focusing on maximum and minimum events. For the most accurate HR, based on performance metrics, we performed a forecast skill of HR to detect floods and droughts, comparing the results with in-situ observations. A statistical temporal series trend was performed for intensity of seasonal floods and droughts in the entire Amazon basin. Results indicate that HR could represent most past extreme events well, compared with in-situ observed data, and was consistent with many events reported in literature. Because of their flow duration, some minor regional events were not reported in literature but were captured by HR. To represent past regional hydrology and seasonal hydrological extreme events, we believe it is feasible to use some large precipitation datasets such as i) climate reanalysis, which is mainly based on a land surface component, and ii) datasets based on merged products. A significant upward trend in intensity was seen in maximum annual discharge (related to floods) in western and northwestern regions and for minimum annual discharge (related to droughts) in south and central-south regions of the Amazon basin. Because of the global coverage of rainfall datasets

  19. Early 21st century snow cover state over the western river basins of the Indus River system

    Science.gov (United States)

    Hasson, S.; Lucarini, V.; Khan, M. R.; Petitta, M.; Bolch, T.; Gioli, G.

    2014-10-01

    In this paper we assess the snow cover and its dynamics for the western river basins of the Indus River system (IRS) and their sub-basins located in Afghanistan, China, India and Pakistan for the period 2001-2012. First, we validate the Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow products from Terra (MOD10A1) and Aqua (MYD10A1) against the Landsat Thematic Mapper/Enhanced Thematic Mapper plus (TM/ETM+) data set, and then improve them for clouds by applying a validated non-spectral cloud removal technique. The improved snow product has been analysed on a seasonal and annual basis against different topographic parameters (aspect, elevation and slope). Our results show a decreasing tendency for the annual average snow cover for the westerlies-influenced basins (upper Indus basin (UIB), Astore, Hunza, Shigar and Shyok) and an increasing tendency for the monsoon-influenced basins (Jhelum, Kabul, Swat and Gilgit). Seasonal average snow cover decreases during winter and autumn, and increases during spring and summer, which is consistent with the observed cooling and warming trends during the respective seasons. Sub-basins at relatively higher latitudes/altitudes show higher variability than basins at lower latitudes/middle altitudes. Northeastern and northwestern aspects feature greater snow cover. The mean end-of-summer regional snow line altitude (SLA) zones range from 3000 to 5000 m a.s.l. for all basins. Our analysis provides an indication of a descending end-of-summer regional SLA zone for most of the studied basins, which is significant for the Shyok and Kabul basins, thus indicating a change in their water resources. Such results are consistent with the observed hydro-climatic data, recently collected local perceptions and glacier mass balances for the investigated period within the UIB. Moreover, our analysis shows a significant correlation between winter season snow cover and the North Atlantic Oscillation (NAO) index of the previous autumn

  20. Finite-frequency P-wave tomography of the Western Canada Sedimentary Basin: Implications for the lithospheric evolution in Western Laurentia

    Science.gov (United States)

    Chen, Yunfeng; Gu, Yu Jeffrey; Hung, Shu-Huei

    2017-02-01

    The lithosphere beneath the Western Canada Sedimentary Basin has potentially undergone Precambrian subduction and collisional orogenesis, resulting in a complex network of crustal domains. To improve the understanding of its evolutionary history, we combine data from the USArray and three regional networks to invert for P-wave velocities of the upper mantle using finite-frequency tomography. Our model reveals distinct, vertically continuous high (> 1%) velocity perturbations at depths above 200 km beneath the Precambrian Buffalo Head Terrane, Hearne craton and Medicine Hat Block, which sharply contrasts with those beneath the Canadian Rockies (lithosphere is substantially thinner beneath the adjacent Buffalo Head Terrane (160 km) and Medicine Hat Block (200 km). These findings are consistent with earlier theories of tectonic assembly in this region, which featured distinct Archean and Proterozoic plate convergences between the Hearne craton and its neighboring domains. The highly variable, bimodally distributed craton thicknesses may also reflect different lithospheric destruction processes beneath the western margin of Laurentia.

  1. Rapid inundation estimates using coastal amplification laws in the Western Mediterranean basin

    Science.gov (United States)

    Gailler, Audrey; Hébert, Hélène; Schindelé, François

    2016-04-01

    Numerical tsunami propagation and inundation models are well developed and have now reached an impressive level of accuracy, especially in locations such as harbors where the tsunami waves are mostly amplified. In the framework of tsunami warning under real-time operational conditions, the main obstacle for the routine use of such numerical simulations remains the slowness of the numerical computation, which is strengthened when detailed grids are required for the precise modeling of the coastline response of an individual harbor. Thus only tsunami offshore propagation modeling tools using a single sparse bathymetric computation grid are presently included within the French Tsunami Warning Center (CENALT), providing rapid estimation of tsunami impact at Western Mediterranean and NE Atlantic basins scale. We present here a work that performs quick estimates of the coastal impact at individual harbors from these high sea forecasting tsunami simulations. The method involves an empirical correction based on the Green's theoretical amplification law. The main limitation is that its application to a given coastal area would require a large database of previous observations, in order to define the empirical parameters of the correction equation. As no tide gage records of significant tsunamis are available for the Western Mediterranean French coasts, we use a set of points of interest distributed along these coasts, where maximum water heights are calculated for both fake events and well-known historical tsunamigenic earthquakes in the area. This synthetic dataset is obtained through accurate numerical tsunami propagation and inundation modeling by using several nested bathymetric grids of increasingly fine resolution close to the shores. Non linear shallow water tsunami modeling performed on a single 2' coarse bathymetric grid are compared to the values given by time-consuming nested grids simulations, in order to check to which extent the simple approach based on the

  2. Variability of mineral dust deposition in the western Mediterranean basin and south-east of France

    Science.gov (United States)

    Vincent, Julie; Laurent, Benoit; Losno, Rémi; Bon Nguyen, Elisabeth; Roullet, Pierre; Sauvage, Stéphane; Chevaillier, Servanne; Coddeville, Patrice; Ouboulmane, Noura; di Sarra, Alcide Giorgio; Tovar-Sánchez, Antonio; Sferlazzo, Damiano; Massanet, Ana; Triquet, Sylvain; Morales Baquero, Rafael; Fornier, Michel; Coursier, Cyril; Desboeufs, Karine; Dulac, François; Bergametti, Gilles

    2016-07-01

    provenance, transport and deposition processes (i.e. wet vs. dry) of dust are different and specific for the different deposition sites in the Mediterranean studied area. The results tend to indicate that wet deposition is the main form of deposition for mineral dust in the western Mediterranean basin, but the contribution of dry deposition (in the sense that no precipitation was detected at the surface) is far from being negligible, and contributes 10 to 46 % to the major dust deposition events, depending on the sampling site.

  3. Early middle Miocene tectonic uplift of the northwestern part of the Qinghai–Tibetan Plateau evidenced by geochemical and mineralogical records in the western Tarim Basin

    NARCIS (Netherlands)

    Wang, Chaowen; Hong, Hanlie; Abels, Hemmo A.; Li, Zhaohui; Cao, Kai; Yin, Ke; Song, Bowen; Xu, Yadong; Ji, Junliang; Zhang, Kexin

    The Tarim Basin in western China has been receiving continuous marine to lacustrine deposits during the Cenozoic as a foreland basin of the Qinghai–Tibetan Plateau (QTP). Clay mineralogy and geochemical proxy data from these sedimentary archives can shed light on climate and tectonic trends. Here we

  4. Forest Composition and Structure Under Various Disturbance Regimes in the Alaknanda River Basin, Western Himalaya

    Directory of Open Access Journals (Sweden)

    Upma Manral

    2017-08-01

    Full Text Available This study explored the resilience of mountain forests in a protected area in Alaknanda River basin, Western Himalaya, to various disturbance scenarios. The resource dependency of village communities in the Kedarnath Wildlife Sanctuary Landscape was studied through a questionnaire survey in 10 villages situated along an elevational gradient. Vegetation sampling was done in government-owned sanctuary forests and community-owned forests, both visited by villagers. Forest community composition, regeneration status, and tree population structure were studied to understand the impact of disturbance on forests and their resistance to anthropogenic alterations. Results indicated a reduction in both fuelwood and fodder consumption with decreasing elevation, with villages at higher elevations and located inside the sanctuary depending more on forest resources. Forests showed evidence of disturbance in the form of lower basal cover, mean canopy cover, regeneration, and disturbance-influenced distribution of shrubs. However, despite the signs of secondary succession, Quercus leucotrichophora forest has retained the original tree species composition. Vegetation recovery on 3 landslide sites at varying successional stages was also studied. The old successional site had higher species richness than early successional sites. The only tree species with adult individuals recorded in early successional sites was Alnus nepalensis, an early successional nitrogen-fixing species. The community composition of the old successional site, at Bandwara, included young individuals of Q. leucotrichophora, the climax species of forests in that elevational range. The current forest structure of both disturbed forest and vegetation recovery on the old succession site indicate the resilient dynamism of native Himalayan forests. Considering the role of mountain forests in achieving sustainable development, it is imperative to study the dynamics of changes in forest community and

  5. Analysis of Coincident HICO and Airborne Hyperspectral Images Over Lake Erie Western Basin HABs

    Science.gov (United States)

    Cline, Michael T., Jr.

    Harmful algal blooms (HABs) produce waterborne toxins that pose a significant threat to people, livestock, and wildlife. Nearly 40 million people in both Canada and the U.S. depend on Great Lakes water. In the summer of 2014, in the Lake Erie Western Basin, an HAB of the cyanobacteria Microcystis was so severe that a do-not-drink advisory was in effect for the greater Toledo area, Ohio. This advisory applied to the water supply to over 400,000 people from a single water intake. Bloom intensity, composition, and spatial variability were investigated by comparing coincidental hyperspectral data from NASA's HICO, and NASA GRC's HSI airborne sensor, with on-lake ASD radiometer measurements and in situ water quality testing as ground reference data. Coincident data sets were obtained with HICO only on one day in 2014, however all other datasets coincide four times in 2015. Remote sensing data were atmospherically corrected using the empirical line method, utilizing dark reference spectra from a nearby asphalt parking lot measured from ASD and HSI radiometers. Cyanobacteria Index (CI) images were created from processed images using the Wynne (2010) algorithm, previously used for MODIS and MERIS imagery. This algorithm-generated CI images provide reliable results for both ground level (R2=0.921), airborne (R2=0.7981), and satellite imagery (R2=0.7794) for seven sampling points. The ability to robustly atmospherically correct and generate useful CI maps from airborne and satellite sensors can provide a time- and cost-effective method for HABs analysis. Timely processing of these high spatial and spectral resolution remote sensing data can aid in management of water intake resources. These results will help to improve methods leading to HABs mapping by testing different algal retrieval algorithms and atmospheric correction techniques using a three tiered hyperspectral sensor approach utilizing satellite, airborne, and ground level sensors, coupled with water quality

  6. Aerosol distribution over the western Mediterranean basin during a Tramontane/Mistral event

    Energy Technology Data Exchange (ETDEWEB)

    Salameh, T.; Menut, L. [Ecole Polytechnique/ENS/UPMC/CNRS, Palaiseau (France). Inst. Pierre Simon Laplace/Lab. de Meteorologie Dynamique; Drobinski, P.; Flamant, C. [UPMC/UVSQ/CNRS, Paris (France). Inst. Pierre Simon Laplace/Service d' Aeronomie; Bessagnet, B. [INERIS, Verneuil en Halatte (France). Inst. National de l' Environnement Industriel et des Risques; Hodzic, A. [National Center for Atmospheric Research, Boulder, CO (United States); Vautard, R. [CEA/UVSQ/CNRS, Gif-sur-Yvette (France). Inst. Pierre Simon Laplace/Lab. des Sciences du Climat et de l' Environnement

    2007-07-01

    This paper investigates experimentally and numerically the time evolution of the spatial distribution of aerosols over the Western Mediterranean basin during the 24 March 1998 Mistral event documented during the FETCH experiment. Mistral and Tramontane are very frequently northerly wind storms (5-15 days per month) accelerated along the Rhone and Aude valleys (France) that can transport natural and anthropogenic aerosols offshore as far as a few hundred kilometers, which can, in turn, have an impact on the radiation budget over the Mediterranean Sea and on precipitation. The spatial distribution of aerosols was documented by means of the airborne lidar LEANDRE-2 and space-borne radiometer SeaWIFS, and a validated mesoscale chemical simulation using the chemistry-transport model CHIMERE with an aerosol module, forced by the non-hydrostatic model MM5. This study shows that: (1) the Mistral and Tramontane contribute to the offshore exportation of a large amount of aerosols originally emitted over continental Europe (in particular, ammonium nitrate in the particulate phase and sulfates) and along the shore from the industrialized and urban areas of Fos-Berre/Marseille. The amount of aerosol loading solely due to the Mistral and Tramontane is as large as 3-4 times the background aerosol amount and the contribution of sea-salt particles to the total aerosol loading and optical depth ranges from 1 to 10% even in such stormy conditions; (2) the aerosol concentration pattern is very unsteady as a result of the time evolution of the two winds (or Genoa cyclone position): The Tramontane wind prevails in the morning hours of 24 March, leaving room for the Mistral wind and an unusually strong Ligurian outflow in the afternoon. The Genoa surface low contributes to advect the aerosols along a cyclonic trajectory that skirts the North African coast and reaches Italy. The wakes trailing downstream the Massif Central and the Alps prevent any horizontal diffusion of the aerosols and

  7. Early 21st century climatology of snow cover for the western river basins of the Indus River System

    Science.gov (United States)

    Hasson, S.; Lucarini, V.; Khan, M. R.; Petitta, M.; Bolch, T.; Gioli, G.

    2013-11-01

    In this paper we assess the snow cover and its dynamics for the western river basins of the Indus River System (IRS) and their sub-basins located in Afghanistan, China, India and Pakistan for the period 2001-2012. Moderate Resolution Imaging Spectro-radiometer (MODIS) daily snow products from Terra (MOD) and Aqua (MYD) have been first improved and then analysed on seasonal and annual basis against different topographic parameters (aspect, elevation and slope). Our applied cloud filtering technique has reduced the cloud cover from 37% (MOD) and 43% (MYD) to 7%, thus improving snow cover estimates from 7% (MOD) and 5% (MYD) to 14% for the area of interest (AOI) during the validation period (2004). Our results show a decreasing tendency for the annual average snow cover for the westerlies-influenced basins (Upper Indus Basin, Astore, Hunza, Shigar, Shyok) and an increasing tendency for the monsoon-influenced basins (Jhelum, Kabul, Swat and Gilgit). Regarding the seasonal snow cover, decrease during winter and autumn and increase during spring and summer has been found, which is consistent with the observed cooling and warming trends during the respective seasons. Sub-basins at relatively higher latitude/altitude show higher variability than basins at lower latitude/mid-altitude. Northeastern and northwestern aspects feature larger snow cover. The mean regional snow line altitude (SLA) zones range between 3000 and 5000 m a.s.l. for all basins. Our analysis provides an indication of a decrease in the regional SLA zone, thus indicating a change in the water resources of the studied basins, particularly for the Upper Indus Basin (UIB). Such results are consistent with the observed hydro-climate data, recently collected local perceptions and glacier mass balances for the investigated period. Moreover, our analysis suggests some potential for the seasonal stream flow forecast as a significant negative correlation has been detected for the inter-annual variability of winter

  8. Gravity anomalies, crustal structure and rift tectonics at the Konkan and Kerala basins, western continental margin of India

    Science.gov (United States)

    Dev, Sheena V.; Radhakrishna, M.; Chand, Shyam; Subrahmanyam, C.

    2012-06-01

    Litho-stratigraphic variation of sedimentary units constructed from seismic sections and gravity anomaly in the Konkan and Kerala basins of the western continental margin of India (WCMI) have been used to model processes such as lithospheric rifting mechanism, its strength, and evolution of flank uplift topography that led to the present-day Western Ghats escarpment. Based on the process-oriented approach, two lithospheric models (necking and magmatic underplating) of evolution of the margin were tested. Both, necking and underplating models suggest an effective elastic thickness (Te) of 5 km and 10 km along Konkan and Kerala basins, respectively and a deep level of necking at 20 km at both basins. Model study suggests that the necking model better explains the observed gravity anomalies in the southern part of the WCMI. A synthesis of these results along with the previously published elastic thickness estimates along the WCMI suggests that a low-to-intermediate strength lithosphere and a deeper level of necking explains the observed flank-uplift topography of the Western Ghats. Process-oriented gravity modelling further suggests that the lateral variations in the lithospheric strength, though not very significant, exist from north to south within a distance of 600 km in the Konkan and Kerala basins along the WCMI at the time of rifting. A comparison with previous Te estimates from coherence analysis along the WCMI indicates that the lithospheric strength did not change appreciably since the time of rifting and it is low both onshore and offshore having a range of 5-15 km.

  9. Food Security, Fisheries and Aquaculture in the Bolivian Amazon ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    scale aquaculture value chains in two pilot areas: capture fisheries in the northern Bolivian Amazon (Paiche) and pond aquaculture of native fish in the Marmoré basin in the northeastern Amazon. The team will analyze the nutritional value of ...

  10. Cosmogenic nuclide and uranium-series dating of old, high shorelines in the western Great Basin, USA

    Science.gov (United States)

    Kurth, G.; Phillips, F.M.; Reheis, M.C.; Redwine, J.L.; Paces, J.B.

    2011-01-01

    Closed-basin pluvial lakes are sensitive recorders of effective moisture, and they provide a terrestrial signal of climate change that can be compared to marine and ice records of glacial-interglacial cycles. Although the most recent deep-lake cycle in the western Great Basin (at ca. 16 ka) has been studied intensively, comparatively little is known about the longer-term Quaternary lacustrine history of the region. Lacustrine features higher than those of the most recent highstand have been discovered in many locations throughout the western Great Basin. Qualitative geomorphic and soil studies of shoreline sequences above the latest Pleistocene level suggest that their ages increase as a function of increasing altitude. The results of cosmogenic nuclide dating using chlorine-36 depth profiles from three sites in Nevada (Walker Lake, Columbus Salt Marsh, and Newark Valley), combined with uranium-series and radiocarbon ages, corroborate the geomorphic and soil evidence. The 36Cl results are consistent with available 14C ages and together indicate that the most recent highstands of all three lakes occurred ca. 20-15 ka, late in marine isotope stage (MIS) 2, as shown by previous ages. The 36Cl ages indicate that older lakes in all three basins reached highstands between 100 and 50 ka, and most likely during MIS 4. Shorelines of this age are at about the same or higher altitudes as the younger, MIS 2 shorelines in those basins. The 36Cl results combined with uranium-series ages and one tephra correlation obtained on shorelines higher in altitude than those of MIS 4 and 2 lakes suggest that there were also major lake highstands in the western Great Basin at ca. 100-200 ka, likely corresponding with MIS 6, and during at least two older periods. From these results, we conclude that the preserved shorelines show an apparent decrease in maximum levels with time, suggesting long-term drying of the region since the early middle Pleistocene. ?? 2011 Geological Society of

  11. Marine environmental changes at the Brazilian equatorial margin related to Amazon River evolution during the Neogene

    Science.gov (United States)

    Lammertsma, Emmy; Troelstra, Simon; Sangiorgi, Francesca; Chemale, Farid, Jr.; do Carmo, Dermeval A.; D'Avila, Roberto; Soares, Emilson; Hoorn, Carina

    2014-05-01

    Today, the nutrient-rich Amazon River outflow causes massive algal blooms in the western equatorial Atlantic Ocean, forming a considerable carbon sink as well as a primary food source in the otherwise oligotrophic surface water. However, the history of this high-productivity system is largely unknown, although a strong relation to the evolution of the Amazon River can be expected. The Amazon submarine fan provides direct evidence for the development of a transcontinental river system, of which the base of the primarily Andean-sourced siliciclastic deposits is dated as late Miocene. Ditch cuttings from Amazon Fan exploration 'Well 2' were made available by Petrobras for microfossil and lithological research. 'Well 2' is located on the uppermost fan at a water depth of 750 meters. Organic-walled dinoflagellate cyst and foraminifer assemblages were studied to reconstruct Neogene marine environmental changes in relation to the Amazon River development. Planktonic foraminifera are present throughout the studied section and largely confirm the already available biostratigraphic age determination based on nannofossils. Benthic foraminifer assemblages indicate that the paleo-water depth has not substantially deviated from current conditions. The ecological affinities of most observed dinocyst taxa are well known, which allows us to reconstruct changes in paleo-productivity based on the assemblages. Mineral composition suggests that local river systems already drained into the Amazon basin before the onset of the transcontinental system, but environmental conditions remained oligotrophic at this time. Decreased abundances of both dinocysts and planktonic foraminifera during the Pleistocene are related to highest sedimentation rates (dilution effect). Overall, a complex interplay of orogenesis, climatic and sea level variations during the Neogene are responsible for the fluvially-induced changes in the marine environment at the Atlantic margin.

  12. Distinguishing and estimating recharge to karst springs in snow and glacier dominated mountainous basins of the western Himalaya, India

    Science.gov (United States)

    Jeelani, Ghulam; Shah, Rouf A.; Deshpande, Rajendrakumar D.; Fryar, Alan E.; Perrin, Jerome; Mukherjee, Abhijit

    2017-07-01

    Recharge assessment is a challenge in snow and glacier dominated Himalayan basins. Quantification of recharge to karst springs in these complex geological environments is important both for hydrologic understanding and for effective water resource management. We used spring hydrographs and environmental tracers (isotopes and solutes) to distinguish and estimate the sources of spring water and to identify the flow paths of the recharging waters in three mountainous basins of the western Himalaya. The karst springs are perennial with high discharge amplitudes. The results indicate that ambient temperature has a strong influence on the hydrological behavior of the springs. Although the spring flow is dominantly controlled by the melting of snow and/or glaciers, rain events produce sharp spikes in spring hydrographs. The facies patterns in springs within the Bringi basin (Ca-HCO3) and the Liddar basin (Ca-HCO3 and Ca-Mg-HCO3) suggest flow dominantly through limestone and dolomite. Higher concentrations of SO42- and Na+ in warm springs of the Kuthar basin indicate flow through carbonate, silicate and other rocks. The isotopic composition (δ18O, δ2H) of precipitation, snowpacks, glacier melt and karst springs show wide variation both in space and time, and are strongly influenced by the basin relief and meteorology. The tracer-based two- and three-component mixing models suggest that the snowmelt dominantly contributes to the spring flow (55-96%), followed by glacier melt (5-36%) and rain (4-34%). Based on tracer tests with good recovery rates, springs are dominantly recharged through point sources rather than by diffuse infiltration. Changes in the timing, form, and amount of winter precipitation substantially affect the timing and magnitude of spring discharge during the rest of the year.

  13. Spectral light absorption by ambient aerosols influenced by biomass burning in the Amazon Basin. I: Comparison and field calibration of absorption measurement techniques

    Science.gov (United States)

    Schmid, O.; Artaxo, P.; Arnott, W. P.; Chand, D.; Gatti, L. V.; Frank, G. P.; Hoffer, A.; Schnaiter, M.; Andreae, M. O.

    2006-08-01

    Spectral aerosol light absorption is an important parameter for the assessment of the radiation budget of the atmosphere. Although on-line measurement techniques for aerosol light absorption, such as the Aethalometer and the Particle Soot Absorption Photometer (PSAP), have been available for two decades, they are limited in accuracy and spectral resolution because of the need to deposit the aerosol on a filter substrate before measurement. Recently, a 7-wavelength (λ) Aethalometer became commercially available, which covers the visible (VIS) to near-infrared (NIR) spectral range (λ=450-950 nm), and laboratory calibration studies improved the degree of confidence in these measurement techniques. However, the applicability of the laboratory calibration factors to ambient conditions has not been investigated thoroughly yet. As part of the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia - SMOke aerosols, Clouds, rainfall and Climate) campaign from September to November 2002 in the Amazon basin we performed an extensive field calibration of a 1-λ PSAP and a 7-λ Aethalometer utilizing a photoacoustic spectrometer (PAS, 532 nm) as reference device. Especially during the dry period of the campaign, the aerosol population was dominated by pyrogenic emissions. The most pronounced artifact of integrating-plate type attenuation techniques (e.g. Aethalometer, PSAP) is due to multiple scattering effects within the filter matrix. For the PSAP, we essentially confirmed the laboratory calibration factor by Bond et al. (1999). On the other hand, for the Aethalometer we found a multiple scattering enhancement of 5.23 (or 4.55, if corrected for aerosol scattering), which is significantly larger than the factors previously reported (~2) for laboratory calibrations. While the exact reason for this discrepancy is unknown, the available data from the present and previous studies suggest aerosol mixing (internal versus external) as a likely cause. For Amazonian

  14. Spectral light absorption by ambient aerosols influenced by biomass burning in the Amazon Basin. I: Comparison and field calibration of absorption measurement techniques

    Directory of Open Access Journals (Sweden)

    O. Schmid

    2006-01-01

    Full Text Available Spectral aerosol light absorption is an important parameter for the assessment of the radiation budget of the atmosphere. Although on-line measurement techniques for aerosol light absorption, such as the Aethalometer and the Particle Soot Absorption Photometer (PSAP, have been available for two decades, they are limited in accuracy and spectral resolution because of the need to deposit the aerosol on a filter substrate before measurement. Recently, a 7-wavelength (λ Aethalometer became commercially available, which covers the visible (VIS to near-infrared (NIR spectral range (λ=450–950 nm, and laboratory calibration studies improved the degree of confidence in these measurement techniques. However, the applicability of the laboratory calibration factors to ambient conditions has not been investigated thoroughly yet. As part of the LBA-SMOCC (Large scale Biosphere atmosphere experiment in Amazonia – SMOke aerosols, Clouds, rainfall and Climate campaign from September to November 2002 in the Amazon basin we performed an extensive field calibration of a 1-λ PSAP and a 7-λ Aethalometer utilizing a photoacoustic spectrometer (PAS, 532 nm as reference device. Especially during the dry period of the campaign, the aerosol population was dominated by pyrogenic emissions. The most pronounced artifact of integrating-plate type attenuation techniques (e.g. Aethalometer, PSAP is due to multiple scattering effects within the filter matrix. For the PSAP, we essentially confirmed the laboratory calibration factor by Bond et al. (1999. On the other hand, for the Aethalometer we found a multiple scattering enhancement of 5.23 (or 4.55, if corrected for aerosol scattering, which is significantly larger than the factors previously reported (~2 for laboratory calibrations. While the exact reason for this discrepancy is unknown, the available data from the present and previous studies suggest aerosol mixing (internal versus external as a likely cause. For

  15. Out of the Tropics: The Pacific, Great Basin Lakes, and Late Pleistocene Water Cycle in the Western United States

    Science.gov (United States)

    Lyle, Mitchell; Heusser, Linda; Ravelo, Christina; Yamamoto, Masanobu; Barron, John; Diffenbaugh, Noah S.; Herbert, Timothy; Andreasen, Dyke

    2012-09-01

    The water cycle in the western United States changed dramatically over glacial cycles. In the past 20,000 years, higher precipitation caused desert lakes to form which have since dried out. Higher glacial precipitation has been hypothesized to result from a southward shift of Pacific winter storm tracks. We compared Pacific Ocean data to lake levels from the interior west and found that Great Basin lake high stands are older than coastal wet periods at the same latitude. Westerly storms were not the source of high precipitation. Instead, air masses from the tropical Pacific were transported northward, bringing more precipitation into the Great Basin when coastal California was still dry. The changing climate during the deglaciation altered precipitation source regions and strongly affected the regional water cycle.

  16. Out of the tropics: the Pacific, Great Basin lakes, and late Pleistocene water cycle in the western United States.

    Science.gov (United States)

    Lyle, Mitchell; Heusser, Linda; Ravelo, Christina; Yamamoto, Masanobu; Barron, John; Diffenbaugh, Noah S; Herbert, Timothy; Andreasen, Dyke

    2012-09-28

    The water cycle in the western United States changed dramatically over glacial cycles. In the past 20,000 years, higher precipitation caused desert lakes to form which have since dried out. Higher glacial precipitation has been hypothesized to result from a southward shift of Pacific winter storm tracks. We compared Pacific Ocean data to lake levels from the interior west and found that Great Basin lake high stands are older than coastal wet periods at the same latitude. Westerly storms were not the source of high precipitation. Instead, air masses from the tropical Pacific were transported northward, bringing more precipitation into the Great Basin when coastal California was still dry. The changing climate during the deglaciation altered precipitation source regions and strongly affected the regional water cycle.

  17. Petroleum resources assessment on the western part of the Kunsan Basin

    Energy Technology Data Exchange (ETDEWEB)

    Park, K.S.; Park, K.P.; Sunwoo, D.; Yoo, D.G.; Cheong, T.J.; Oh, J.H.; Bong, P.Y.; Son, J.D.; Lee, H.Y.; Ryu, B.J.; Son, B.K.; Hwang, I.G.; Kwon, Y.I.; Lee, Y.J.; Kim, H.J. [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1997-12-01

    Palynomorphs including spores, pollen and organic-walled microfossils and calcareous microfossils such as ostracods, charophytes and gastropods were studied for the biostratigraphic work of Kachi-1 and IIH-1Xa wells. All the microfossils yielded from two wells indicate nonmarine environment ranging from shallow lacustrine to fluvial one. The paleoclimates have been fluctuated between subtropical and cool temperate with arid/humid alternating conditions. The fluvial sandstone of the interval between 2017 m and 2021 m could be a potential reservoir rock in the well Kachi-1. The sandstone from 1587 m to 1592 could be also a potential reservoir rock even if further study is necessary for the cap rock. Content of organic matter is very low and the type is compared to III in the section penetrated by the above two wells. Thermal maturity might reach top of oil window at depth about 1200 m by Tmax and about 1300 m by biomarker analysis in the Kachi-1 well. On the basis of illite crystallinity, the top of oil generation zone could be located at the depth 1600 m. The thermal maturity could not be determined in the IIH-1Xa well, because of the extremely low organic matter content or bad state of samples. Hydrocarbon genetic potential is almost null in the both well except for a few sample in the thermally immature interval. Analysis of approximately 3,300 Line-km of multichannel seismic data integrated with 3 well data provides an insight of structural evolution of the western part of the Yellow Sea Basin. Tectonics of the rifting phase have been established on the basis of structural and stratigraphic analyses of depositional sequences and their seismic expressions. Based on available well data, the rifting probably began in the Cretaceous time had continued until Paleocene. It is considered that compressional force immediately after rifting event deformed sedimentary sections. During the period of Paleocene to middle Miocene, the sediments were deposited in stable

  18. Intraplate seismicity along the Gedi Fault in Kachchh rift basin of western India

    Science.gov (United States)

    Joshi, Vishwa; Rastogi, B. K.; Kumar, Santosh

    2017-08-01

    The Kachchh rift basin is located on the western continental margin of India and has a history of experiencing large to moderate intraplate earthquakes with M ≥ 5. During the past two centuries, two large earthquakes of Mw 7.8 (1819) and Mw 7.7 (2001) have occurred in the Kachchh region, the latter with an epicenter near Bhuj. The aftershock activity of the 2001 Bhuj earthquake is still ongoing with migration of seismicity. Initially, epicenters migrated towards the east and northeast within the Kachchh region but, since 2007, it has also migrated to the south. The triggered faults are mostly within 100 km and some up to 200 km distance from the epicentral area of the mainshock. Most of these faults are trending in E-W direction, and some are transverse. It was noticed that some faults generate earthquakes down to the Moho depth whereas some faults show earthquake activity within the upper crustal volume. The Gedi Fault, situated about 50 km northeast of the 2001 mainshock epicenter, triggered the largest earthquake of Mw 5.6 in 2006. We have carried out detailed seismological studies to evaluate the seismic potential of the Gedi Fault. We have relocated 331 earthquakes by HypoDD to improve upon location errors. Further, the relocated events are used to estimate the b value, p value, and fractal correlation dimension Dc of the fault zone. The present study indicates that all the events along the Gedi Fault are shallow in nature, with focal depths less than 20 km. The estimated b value shows that the Gedi aftershock sequence could be classified as Mogi's type 2 sequence, and the p value suggests a relatively slow decay of aftershocks. The fault plane solutions of some selected events of Mw > 3.5 are examined, and activeness of the Gedi Fault is assessed from the results of active fault studies as well as GPS and InSAR results. All these results are critically examined to evaluate the material properties and seismic potential of the Gedi Fault that may be useful

  19. Aerosol distribution over the western Mediterranean basin during a Tramontane/Mistral event

    Directory of Open Access Journals (Sweden)

    T. Salameh

    2007-11-01

    Full Text Available This paper investigates experimentally and numerically the time evolution of the spatial distribution of aerosols over the Western Mediterranean basin during the 24 March 1998 Mistral event documented during the FETCH experiment. Mistral and Tramontane are very frequently northerly wind storms (5–15 days per month accelerated along the Rh^one and Aude valleys (France that can transport natural and anthropogenic aerosols offshore as far as a few hundred kilometers, which can, in turn, have an impact on the radiation budget over the Mediterranean Sea and on precipitation.

    The spatial distribution of aerosols was documented by means of the airborne lidar LEANDRE-2 and space-borne radiometer SeaWIFS, and a validated mesoscale chemical simulation using the chemistry-transport model CHIMERE with an aerosol module, forced by the non-hydrostatic model MM5.

    This study shows that: (1 the Mistral and Tramontane contribute to the offshore exportation of a large amount of aerosols originally emitted over continental Europe (in particular, ammonium nitrate in the particulate phase and sulfates and along the shore from the industrialized and urban areas of Fos-Berre/Marseille. The amount of aerosol loading solely due to the Mistral and Tramontane is as large as 3–4 times the background aerosol amount and the contribution of sea-salt particles to the total aerosol loading and optical depth ranges from 1 to 10% even in such stormy conditions; (2 the aerosol concentration pattern is very unsteady as a result of the time evolution of the two winds (or Genoa cyclone position: The Tramontane wind prevails in the morning hours of 24 March, leaving room for the Mistral wind and an unusually strong Ligurian outflow in the afternoon. The Genoa surface low contributes to advect the aerosols along a cyclonic trajectory that skirts the North African coast and reaches Italy. The wakes trailing downstream the Massif Central and the Alps prevent any

  20. Aerosol distribution over the western Mediterranean basin during a Tramontane/Mistral event

    Directory of Open Access Journals (Sweden)

    T. Salameh

    2007-11-01

    Full Text Available This paper investigates experimentally and numerically the time evolution of the spatial distribution of aerosols over the Western Mediterranean basin during the 24 March 1998 Mistral event documented during the FETCH experiment. Mistral and Tramontane are very frequently northerly wind storms (5–15 days per month accelerated along the Rh\\^one and Aude valleys (France that can transport natural and anthropogenic aerosols offshore as far as a few hundred kilometers, which can, in turn, have an impact on the radiation budget over the Mediterranean Sea and on precipitation. The spatial distribution of aerosols was documented by means of the airborne lidar LEANDRE-2 and space-borne radiometer SeaWIFS, and a validated mesoscale chemical simulation using the chemistry-transport model CHIMERE with an aerosol module, forced by the non-hydrostatic model MM5. This study shows that: (1 the Mistral and Tramontane contribute to the offshore exportation of a large amount of aerosols originally emitted over continental Europe (in particular, ammonium nitrate in the particulate phase and sulfates and along the shore from the industrialized and urban areas of Fos-Berre/Marseille. The amount of aerosol loading solely due to the Mistral and Tramontane is as large as 3–4 times the background aerosol amount and the contribution of sea-salt particles to the total aerosol loading and optical depth ranges from 1 to 10% even in such stormy conditions; (2 the aerosol concentration pattern is very unsteady as a result of the time evolution of the two winds (or Genoa cyclone position: The Tramontane wind prevails in the morning hours of 24 March, leaving room for the Mistral wind and an unusually strong Ligurian outflow in the afternoon. The Genoa surface low contributes to advect the aerosols along a cyclonic trajectory that skirts the North African coast and reaches Italy. The wakes trailing downstream the Massif Central and the Alps prevent any horizontal diffusion

  1. Orogenic inheritance in Death Valley region, western US Basin and Range: implications for Neogene crustal extension.

    Science.gov (United States)

    Lima, R. D.; Hayman, N. W.; Prior, M. G.; Stockli, D. F.; Kelly, E. D.

    2016-12-01

    Deformation and temperature evolution during orogenic stages may influence later fabric development, thus controlling large-scale extensional processes that can occur millions of years later. Here, we describe pressure-temperature and fabric evolution from the Death Valley (DV) region and show how inherited fabrics, formed in late orogenic stages during Late Cretaceous time, influenced later Neogene age Basin and Range (BR) extension. The DV region is one of the most extended and thinned regions in the western US BR province, and the two of the ranges that bound the eastern valley expose basement rocks exhumed during the Neogene extension. In the Funeral range, it has been established that older (Precambrian) basement underwent Mesozoic age syn-deformational metamorphism during the Sevier-Laramide orogeny. In contrast, the Black Mountains record widespread tectonic stretching and magmatism of Miocene age on Precambrian basement, and have, overall, been lacking previous evidence of Mesozoic metamorphism and fabric development. In the Funeral Range Late Cretaceous migmatitic fabrics were overprinted by zones of high-strain fabrics formed due to melt-consuming reaction that define an overall P-T cooling path likely during late- to post-orogenesis. These fabrics form interconnected layers of quartz + biotite aggregates, in which individual quartz grains lack evidence of intracrystalline plastic deformation and show consistently random [c]-axis microfabrics. This suggests coupled reaction-diffusion processes that favored diffusion-assisted creep. New geochronometric results of melt products in the Black Mountains show evidence of partial melting of Late Cretaceous age. Contrasting with the neighboring Funeral Range, overprinting by extensional fabrics of Miocene age is widespread, and consists of high-strain, anastomosing foliation composed of retrograde products from preexisting, higher-temperature fabrics. These include interconnected fine-grained chlorite + quartz

  2. Intraplate seismicity along the Gedi Fault in Kachchh rift basin of western India

    Science.gov (United States)

    Joshi, Vishwa; Rastogi, B. K.; Kumar, Santosh

    2017-11-01

    The Kachchh rift basin is located on the western continental margin of India and has a history of experiencing large to moderate intraplate earthquakes with M ≥ 5. During the past two centuries, two large earthquakes of Mw 7.8 (1819) and Mw 7.7 (2001) have occurred in the Kachchh region, the latter with an epicenter near Bhuj. The aftershock activity of the 2001 Bhuj earthquake is still ongoing with migration of seismicity. Initially, epicenters migrated towards the east and northeast within the Kachchh region but, since 2007, it has also migrated to the south. The triggered faults are mostly within 100 km and some up to 200 km distance from the epicentral area of the mainshock. Most of these faults are trending in E-W direction, and some are transverse. It was noticed that some faults generate earthquakes down to the Moho depth whereas some faults show earthquake activity within the upper crustal volume. The Gedi Fault, situated about 50 km northeast of the 2001 mainshock epicenter, triggered the largest earthquake of Mw 5.6 in 2006. We have carried out detailed seismological studies to evaluate the seismic potential of the Gedi Fault. We have relocated 331 earthquakes by HypoDD to improve upon location errors. Further, the relocated events are used to estimate the b value, p value, and fractal correlation dimension Dc of the fault zone. The present study indicates that all the events along the Gedi Fault are shallow in nature, with focal depths less than 20 km. The estimated b value shows that the Gedi aftershock sequence could be classified as Mogi's type 2 sequence, and the p value suggests a relatively slow decay of aftershocks. The fault plane solutions of some selected events of Mw > 3.5 are examined, and activeness of the Gedi Fault is assessed from the results of active fault studies as well as GPS and InSAR results. All these results are critically examined to evaluate the material properties and seismic potential of the Gedi Fault that may be useful

  3. Variability of mineral dust deposition in the western Mediterranean basin and south-east of France

    Directory of Open Access Journals (Sweden)

    J. Vincent

    2016-07-01

    than 80 % of the major dust deposition events are recorded at only one station, suggesting that the dust provenance, transport and deposition processes (i.e. wet vs. dry of dust are different and specific for the different deposition sites in the Mediterranean studied area. The results tend to indicate that wet deposition is the main form of deposition for mineral dust in the western Mediterranean basin, but the contribution of dry deposition (in the sense that no precipitation was detected at the surface is far from being negligible, and contributes 10 to 46 % to the major dust deposition events, depending on the sampling site.

  4. Sources and mixing state of summertime background aerosol in the north-western Mediterranean basin

    Directory of Open Access Journals (Sweden)

    J. Arndt

    2017-06-01

    Full Text Available An aerosol time-of-flight mass spectrometer (ATOFMS was employed to provide real-time single particle mixing state and thereby source information for aerosols impacting the western Mediterranean basin during the ChArMEx-ADRIMED and SAF-MED campaigns in summer 2013. The ATOFMS measurements were made at a ground-based remote site on the northern tip of Corsica. Twenty-seven distinct ATOFMS particle classes were identified and subsequently grouped into eight general categories: EC-rich (elemental carbon, K-rich, Na-rich, amines, OC-rich (organic carbon, V-rich, Fe-rich and Ca-rich particles. Mass concentrations were reconstructed for the ATOFMS particle classes and found to be in good agreement with other co-located quantitative measurements (PM1, black carbon (BC, organic carbon, sulfate mass and ammonium mass. Total ATOFMS reconstructed mass (PM2. 5 accounted for 70–90 % of measured PM10 mass and was comprised of regionally transported fossil fuel (EC-rich and biomass burning (K-rich particles. The accumulation of these transported particles was favoured by repeated and extended periods of air mass stagnation over the western Mediterranean during the sampling campaigns. The single particle mass spectra proved to be valuable source markers, allowing the identification of fossil fuel and biomass burning combustion sources, and was therefore highly complementary to quantitative measurements made by Particle into Liquid Sampler ion chromatography (PILS-IC and an aerosol chemical speciation monitor (ACSM, which have demonstrated that PM1 and PM10 were comprised predominantly of sulfate, ammonium and OC. Good temporal agreement was observed between ATOFMS EC-rich and K-rich particle mass concentrations and combined mass concentrations of BC, sulfate, ammonium and low volatility oxygenated organic aerosol (LV-OOA. This combined information suggests that combustion of fossil fuels and biomass produced primary EC- and OC-containing particles, which

  5. Stratigraphy and Ar/Ar geochronology of the Miocene lignite-bearing Tunçbilek-Domaniç Basin, western Anatolia

    Science.gov (United States)

    Helvacı, C.; Ersoy, E. Y.; Billor, M. Z.

    2017-07-01

    The Tunçbilek-Domaniç Basin is one of the Neogene basins containing economic coal deposits in western Anatolia, Turkey. The basin fill represents fluvial to lacustrine sedimentary units which are interlayered with volcanic rocks with bimodal composition. In order to reveal the stratigraphy and the exact ages of the basin fill and coal deposits, and to explore the tectonic evolution of the basin, we present new field data and Ar/Ar age data from the volcanic units. The field studies and the age data indicate that the whole basin fills were deposited between 23 and 19 Ma (Aquitanian-Early Burdigalian) without any unconformity. Taking into account the ages of the coal-bearing sedimentary units in the other Neogene basins in the region, it is concluded that most of the economic coal deposits in the western Anatolia were formed during Aquitanian. The field studies also show that the deposition of the sedimentary units in the basin was controlled by the NE-SW-trending strike- to oblique-slip normal faults. In a regional scale, tectonic evolution of the Tunçbilek-Domaniç Basin is linked to the differential stretching in the hanging wall of the southerly located, a crustal-scale low-angle detachment fault (the Simav detachment fault) that controlled the Early Miocene exhumation of the Menderes Extensional Core Complex.

  6. Solute load concentrations in some streams in the Upper Osun and Owena drainage basins, central western Nigeria

    Science.gov (United States)

    Jeje, L. K.; Ogunkoya, O. O.; Oluwatimilehin, J. M.

    1999-12-01

    The solute load dynamics of 12 third-order streams in central western Nigeria are presented, during storm and non-storm runoff events. The relevance of the Walling and Foster model for explaining storm period solute load dynamics in the humid tropical environment was assessed and it was found that this model was generally applicable to the study area. Exceptions appear to be streams draining settlements and/or farms where fertilizers are applied heavily. The solute load ranged from 5 mg l -1 to 580 mg l -1 with streams draining basins with tree-crop plantations ( Theobroma cacao, Cola sp.) as the dominant land cover having the highest solute load.

  7. Impacts of future deforestation and climate change on the hydrology of the Amazon Basin: a multi-model analysis with a new set of land-cover change scenarios

    Science.gov (United States)

    Guimberteau, Matthieu; Ciais, Philippe; Ducharne, Agnès; Boisier, Juan Pablo; Dutra Aguiar, Ana Paula; Biemans, Hester; De Deurwaerder, Hannes; Galbraith, David; Kruijt, Bart; Langerwisch, Fanny; Poveda, German; Rammig, Anja; Andres Rodriguez, Daniel; Tejada, Graciela; Thonicke, Kirsten; Von Randow, Celso; Von Randow, Rita C. S.; Zhang, Ke; Verbeeck, Hans

    2017-03-01

    Deforestation in Amazon is expected to decrease evapotranspiration (ET) and to increase soil moisture and river discharge under prevailing energy-limited conditions. The magnitude and sign of the response of ET to deforestation depend both on the magnitude and regional patterns of land-cover change (LCC), as well as on climate change and CO2 levels. On the one hand, elevated CO2 decreases leaf-scale transpiration, but this effect could be offset by increased foliar area density. Using three regional LCC scenarios specifically established for the Brazilian and Bolivian Amazon, we investigate the impacts of climate change and deforestation on the surface hydrology of the Amazon Basin for this century, taking 2009 as a reference. For each LCC scenario, three land surface models (LSMs), LPJmL-DGVM, INLAND-DGVM and ORCHIDEE, are forced by bias-corrected climate simulated by three general circulation models (GCMs) of the IPCC 4th Assessment Report (AR4). On average, over the Amazon Basin with no deforestation, the GCM results indicate a temperature increase of 3.3 °C by 2100 which drives up the evaporative demand, whereby precipitation increases by 8.5 %, with a large uncertainty across GCMs. In the case of no deforestation, we found that ET and runoff increase by 5.0 and 14 %, respectively. However, in south-east Amazonia, precipitation decreases by 10 % at the end of the dry season and the three LSMs produce a 6 % decrease of ET, which is less than precipitation, so that runoff decreases by 22 %. For instance, the minimum river discharge of the Rio Tapajós is reduced by 31 % in 2100. To study the additional effect of deforestation, we prescribed to the LSMs three contrasted LCC scenarios, with a forest decline going from 7 to 34 % over this century. All three scenarios partly offset the climate-induced increase of ET, and runoff increases over the entire Amazon. In the south-east, however, deforestation amplifies the decrease of ET at the end of dry season

  8. Assessment of waterlogging in agricultural megaprojects in the closed drainage basins of the Western Desert of Egypt

    Science.gov (United States)

    El Bastawesy, M.; Ramadan Ali, R.; Faid, A.; El Osta, M.

    2013-04-01

    This paper investigates the development of waterlogging in the cultivated and arable areas within typical dryland closed drainage basins (e.g. the Farafra and Baharia Oases), which are located in the Western Desert of Egypt. Multi-temporal remote sensing data of the Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+) were collected and processed to detect the land cover changes; cultivations, and the extent of water ponds and seepage channels. The Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) has been processed to delineate the catchment morphometrical parameters (i.e. drainage networks, catchment divides and surface areas of different basins) and to examine the spatial distribution of cultivated fields and their relation to the extracted drainage networks. The soil of these closed drainage basins is mainly shallow and lithic with high calcium carbonate content; therefore, the downward percolation of excess irrigation water is limited by the development of subsurface hardpan, which also saturates the upper layer of soil with water. The subsurface seepage from the newly cultivated areas in the Farafra Oasis has revealed the pattern of buried alluvial channels, which are waterlogged and outlined by the growth of diagnostic saline shrubs. Furthermore, the courses of these waterlogged channels are coinciding with their counterparts of the SRTM DEM, and the recent satellite images show that the surface playas in the downstream of these channels are partially occupied by water ponds. On the other hand, a large water pond has occupied the main playa and submerged the surrounding fields, as a large area has been cultivated within a relatively small closed drainage basin in the Baharia Oasis. The geomorphology of closed drainage basins has to be considered when planning for a new cultivation in dryland catchments to better control waterlogging hazards. The "dry-drainage" concept can be implemented as the drainage and seepage water can be

  9. Assessment of waterlogging in agricultural megaprojects in the closed drainage basins of the Western Desert of Egypt

    Directory of Open Access Journals (Sweden)

    M. El Bastawesy

    2013-04-01

    Full Text Available This paper investigates the development of waterlogging in the cultivated and arable areas within typical dryland closed drainage basins (e.g. the Farafra and Baharia Oases, which are located in the Western Desert of Egypt. Multi-temporal remote sensing data of the Landsat Thematic Mapper (TM and Enhanced Thematic Mapper (ETM+ were collected and processed to detect the land cover changes; cultivations, and the extent of water ponds and seepage channels. The Shuttle Radar Topography Mission (SRTM digital elevation model (DEM has been processed to delineate the catchment morphometrical parameters (i.e. drainage networks, catchment divides and surface areas of different basins and to examine the spatial distribution of cultivated fields and their relation to the extracted drainage networks. The soil of these closed drainage basins is mainly shallow and lithic with high calcium carbonate content; therefore, the downward percolation of excess irrigation water is limited by the development of subsurface hardpan, which also saturates the upper layer of soil with water. The subsurface seepage from the newly cultivated areas in the Farafra Oasis has revealed the pattern of buried alluvial channels, which are waterlogged and outlined by the growth of diagnostic saline shrubs. Furthermore, the courses of these waterlogged channels are coinciding with their counterparts of the SRTM DEM, and the recent satellite images show that the surface playas in the downstream of these channels are partially occupied by water ponds. On the other hand, a large water pond has occupied the main playa and submerged the surrounding fields, as a large area has been cultivated within a relatively small closed drainage basin in the Baharia Oasis. The geomorphology of closed drainage basins has to be considered when planning for a new cultivation in dryland catchments to better control waterlogging hazards. The "dry-drainage" concept can be implemented as the drainage and

  10. Diet and environment of a mid-Pliocene fauna in the Zanda Basin (western Himalaya): Paleo-elevation implications

    Science.gov (United States)

    Wang, Y.; Xu, Y.; Khawaja, S. N.; Wang, X.; Passey, B. H.; Zhang, C.; Li, Q.; Tseng, Z. J.; Takeuchi, G.; Deng, T.; Xie, G.

    2011-12-01

    A mid-Pliocene fauna (3.1-4.0 Ma) was recently discovered in the Zanda Basin in western Himalaya, at an elevation of about 4200 m above sea level. These fossil materials provide a unique window for examining the linkage among tectonic, climatic and biotic changes. Here we report the initial results from isotopic analyses of this fauna and of modern herbivores in the Zanda Basin. The δ13C values of enamel samples from modern wild Tibetan ass, horse, cow and goat from the Zanda Basin are -9.1±2.1%, which indicate a diet comprising predominantly of C3 plants and are consistent with the current dominance of C3 vegetation in the area. The enamel-δ13C values of the fossil horse, rhino, deer, and bovid are -9.6±0.8%, indicating that these ancient mammals, like modern herbivores in the area, fed primarily on C3 vegetation and lived in an environment dominated by C3 plants. The enamel-δ18O values of mid-Pliocene obligate drinkers (i.e., horse and rhino) are lower than those of their modern counterpart, most likely indicating a shift in climate to much drier conditions after ~3-4 Ma. Preliminary paleo-temperature estimates derived from a fossil-based temperature proxy as well as the "clumped isotope" thermometer for the mid-Pliocene Zanda Basin, although somewhat equivocal, are close to the present-day mean annual temperature in the area, suggesting that the paleo-elevation of the Zanda Basin in the mid-Pliocene was similar to its present-day elevation.

  11. Discriminant analysis for characterization of hydrochemistry of two mountain river basins of contrasting climates in the southern Western Ghats, India.

    Science.gov (United States)

    Thomas, Jobin; Joseph, Sabu; Thrivikramji, K P

    2015-06-01

    Discriminant analysis (DA) was performed on river hydrochemistry data for three seasons (i.e., monsoon (MON), post-monsoon (POM), and pre-monsoon (PRM)) to examine the spatio-temporal hydrochemical variability of two mountain river basins (Muthirapuzha River Basin (MRB) and Pambar River Basin (PRB)) of the southern Western Ghats, India. Although the river basins drain tropical mountainous terrain, climate and degree of anthropogenic disturbances show significant differences (i.e., humid, more disturbed MRB vs semiarid, less disturbed PRB). In MRB, TDS, Na(+), pH, Mg(2+), and K(+) are the attributes responsible for significant hydrochemical variations between the seasons, while Cl(-), TH, and Na(+) are the predictors in PRB. The temporal discriminant models imply the importance of rainfall pattern, relative contribution of groundwater toward stream discharge and farming activities in hydrochemistry between the seasons. Inclusion of hydrochemical attributes (in the temporal discriminant functions) that can be derived from both natural and anthropogenic sources suggests that ionic enrichment strongly depends on the seasons, and is mainly due to the variability in the intensity of anthropogenic activities as well as fluctuations in river discharge. In spatial discriminant models, Cl(-) is the only variable responsible for hydrochemical variations between the basins (during MON), whereas Si discriminates during POM and PRM, implying the role of atmospheric supply, anthropogenic modifications as well as intensity of weathering. In the spatial discrimination models, misclassification of hydrochemistry data between MRB and PRB can be attributed to the overlapping effect of humid climate of MRB extending toward the upstream of (semiarid) PRB. This study underscores the versatility of DA in deciphering the significance of climatic controls on hydrochemical composition of tropical mountain rivers.

  12. Franciscan olistoliths in Upper Cretaceous conglomerate deposits, Western Transverse Ranges, California: Implications for basin morphology and tectonic history

    Energy Technology Data Exchange (ETDEWEB)

    Reed, W.E.; Campbell, M.D. (Univ. of California, Los Angeles, CA (United States). Dept. of Earth and Space Sciences)

    1993-04-01

    Compositional analyses reveal that Upper Cretaceous sediments exposed in the Western Transverse Ranges of CA were deposited in submarine fan systems in a forearc basin. Point count data suggest a magmatic arc/recycled orogen as the dominant provenance for these sediments. Paleocurrent measurements from conglomerates in these sediments yield a northerly transport direction. Removal of ca. 90[degree] of clockwise rotation and 70 km of right-lateral slip restore this section to a position west of the San Diego area. The forearc basin would have had a N-S orientation, with the bulk of sediments supplied by the Peninsular Ranges to the east. Evidence of the erosion of the accretionary wedge is provided by the presence of large, internally stratified olistoliths of Franciscan material interbedded with and surrounded by upper Cretaceous conglomerate. Petrographic, quantitative SEM, and microprobe analyses indicate the presence of diagnostic Franciscan mineralogy, including glaucophane, riebeckite, lawsonite, and serpentine. Olistoclasts of chert, jadeitic graywacke, serpentine, and blueschist are found intermixed with the conglomerates in close association with the olistoliths. This association provides strong field evidence that recirculation of melange material within the subduction zone was active and well-established by late Cretaceous time. Inferences regarding the forearc system morphology can be drawn from these observations. The occurrence of coarse, easterly-derived conglomerates surrounded by large, stratified, but sheared, westerly-derived Franciscan debris, suggests a narrow, relatively steep-sided basin. Paleocurrent measurements gave no indication of axial transport within the basin. This morphology suggests that, in late Cretaceous time, the forearc basin was youthful, with a narrow arc-trench gap. Thus, relative convergence rates between the North American and Pacific plates were possibly slower than Tertiary convergence rates.

  13. THE OLIGOCENE MOLLUSC FAUNA OF THE PIEDMONT BASIN (NORTH-WESTERN ITALY I. SCAPHOPODA AND ARCHAEOGASTROPODA

    Directory of Open Access Journals (Sweden)

    M. CRISTINA BONCI

    2000-07-01

    Full Text Available The aim of the present work is to study the Oligocene Scaphopoda and Archaeogastropoda of the Tertiary Piedmont Basin (T.P.B., aiming towards an overall revision of the Oligocene mollusc fauna of this Basin. Five taxa of Scaphopoda and twenty-eight taxa of Archaeogastropoda have been analysed; among these a new species of Nerita (Theliostyla is proposed. 

  14. Source to sink: Evolution of lignin composition in the Madre de Dios River system with connection to the Amazon basin and offshore

    OpenAIRE

    Feng, Xiaojuan; Feakins, Sarah J.; Liu, Zongguang; Ponton, Camilo; Wang, Renée Z.; Karkabi, Elias; Galy, Valier; Berelson, William M.; Nottingham, Andrew T.; Meir, Patrick; West, A. Joshua

    2016-01-01

    While lignin geochemistry has been extensively investigated in the Amazon River, little is known about lignin distribution and dynamics within deep, stratified river channels or its transformations within soils prior to delivery to rivers. We characterized lignin phenols in soils, river particulate organic matter (POM), and dissolved organic matter (DOM) across a 4 km elevation gradient in the Madre de Dios River system, Peru, as well as in marine sediments to investigate the source-to-sink e...

  15. Groundwater quality in the Western San Joaquin Valley study unit, 2010: California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.

    2017-06-09

    Water quality in groundwater resources used for public drinking-water supply in the Western San Joaquin Valley (WSJV) was investigated by the USGS in cooperation with the California State Water Resources Control Board (SWRCB) as part of its Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project. The WSJV includes two study areas: the Delta–Mendota and Westside subbasins of the San Joaquin Valley groundwater basin. Study objectives for the WSJV study unit included two assessment types: (1) a status assessment yielding quantitative estimates of the current (2010) status of groundwater quality in the groundwater resources used for public drinking water, and (2) an evaluation of natural and anthropogenic factors that could be affecting the groundwater quality. The assessments characterized the quality of untreated groundwater, not the quality of treated drinking water delivered to consumers by water distributors.The status assessment was based on data collected from 43 wells sampled by the U.S. Geological Survey for the GAMA Priority Basin Project (USGS-GAMA) in 2010 and data compiled in the SWRCB Division of Drinking Water (SWRCB-DDW) database for 74 additional public-supply wells sampled for regulatory compliance purposes between 2007 and 2010. To provide context, concentrations of constituents measured in groundwater were compared to U.S. Environmental Protection Agency (EPA) and SWRCB-DDW regulatory and non-regulatory benchmarks for drinking-water quality. The status assessment used a spatially weighted, grid-based method to estimate the proportion of the groundwater resources used for public drinking water that has concentrations for particular constituents or class of constituents approaching or above benchmark concentrations. This method provides statistically unbiased results at the study-area scale within the WSJV study unit, and permits comparison of the two study areas to other areas assessed by the GAMA Priority Basin Project

  16. Socio-hydrologic Perspectives of the Co-evolution of Humans and Water in the Tarim River Basin, Western China

    Science.gov (United States)

    Liu, Ye; Tian, Fuqiang; Hu, Heping; Liu, Dengfeng; Sivapalan, Murugesu

    2013-04-01

    Socio-hydrology studies the co-evolution of coupled human-water systems, which is of great importance for long-term sustainable water resource management in basins suffering from serious eco-environmental degradation. Process socio-hydrology can benefit from the exploring the patterns of historical co-evolution of coupled human-water systems as a way to discovering the organizing principles that may underpin their co-evolution. As a self-organized entity, the human-water system in a river basin would evolve into certain steady states over a sufficiently long time but then could also experience sudden shifts due to internal or external disturbances that exceed system thresholds. In this study, we discuss three steady states (also called stages in the social sciences, including natural, human exploitation and recovery stages) and transitions between these during the past 1500 years in the Tarim River Basin of Western China, which a rich history of civilization including its place in the famous Silk Road that connected China to Europe. Specifically, during the natural stage with a sound environment that existed before the 19th century, shifts in the ecohydrological regime were mainly caused by environmental changes such river channel migration and climate change. During the human exploitation stages in the 5th and again in the 19th-20th centuries, however, humans gradually became the main drivers for system evolution, during which the basin experienced rapid population growth, fast socio-economic development and intense human activities. By the 1970s, after 200 years of colonization, the Tarim River Basin evolved into a new regime with vulnerable ecosystem and water system, and suffered from serious water shortages and desertification. Human society then began to take a critical look into the effects of their activities and reappraise the impact of human development on the ecohydrological system, which eventually led the basin into a treatment and recovery stage

  17. 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.

  18. Implications of Spatial Variability in Heat Flow for Geothermal Resource Evaluation in Large Foreland Basins: The Case of the Western Canada Sedimentary Basin

    Directory of Open Access Journals (Sweden)

    Simon Weides

    2014-04-01

    Full Text Available Heat flow and geothermal gradient of the sedimentary succession of the Western Canada Sedimentary Basin (WCSB are mapped based on a large thermal database. Heat flow in the deep part of the basin varies from 30 mW/m2 in the south to high 100 mW/m2 in the north. As permeable strata are required for a successful geothermal application, the most important aquifers are discussed and evaluated. Regional temperature distribution within different aquifers is mapped for the first time, enabling a delineation of the most promising areas based on thermal field and aquifer properties. Results of previous regional studies on the geothermal potential of the WCSB are newly evaluated and discussed. In parts of the WCSB temperatures as high as 100–210 °C exist at depths of 3–5 km. Fluids from deep aquifers in these “hot” regions of the WCSB could be used in geothermal power plants to produce electricity. The geothermal resources of the shallower parts of the WCSB (>2 km could be used for warm water provision (>50 °C or district heating (>70 °C in urban areas.

  19. Regional and Local Trends in helium isotopes, basin and rangeprovince, western North America: Evidence for deep permeablepathways

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, B. Mack; van Soest, Matthijs C.

    2005-07-15

    Fluids from the western margin of the Basin and Range have helium isotope ratios as high as {approx}6-7 Ra, indicating a strong mantle melt influence and consistent with recent and current volcanic activity. Moving away from these areas, helium isotope ratios decrease rapidly to ''background'' values of around 0.6 Ra, and then gradually decrease toward the east to low values of {approx}0.1 Ra at the eastern margin of the Basin and Range. Superimposed on this general regional trend are isolated features with elevated helium isotope ratios (0.8-2.1 Ra) compared to the local background. Spring geochemistry and local geology indicate that these ''He-spikes'' are not related to current or recent magmatic activity, suggesting that the spikes may reflect either localized zones deep mantle melting or deep permeable pathways (faults) with high vertical fluid flowrates. A detailed study of one of the He-spikes (Dixie Valley and the Stillwater Range Front Fault system), indicates that features with high 3He/4He ratios are confined to the range front normal faults characteristic of the extensional regime in the Basin and Range, suggesting that these faults are deep permeable pathways. However, not all range front fault systems transmit fluids with a mantle signature, implying that not all have deep permeable pathways.

  20. Cenozoic sedimentation in the Mumbai Offshore Basin: Implications for tectonic evolution of the western continental margin of India

    Science.gov (United States)

    Nair, Nisha; Pandey, Dhananjai K.

    2018-02-01

    Interpretation of multichannel seismic reflection data along the Mumbai Offshore Basin (MOB) revealed the tectonic processes that led to the development of sedimentary basins during Cenozoic evolution. Structural interpretation along three selected MCS profiles from MOB revealed seven major sedimentary sequences (∼3.0 s TWT, thick) and the associated complex fault patterns. These stratigraphic sequences are interpreted to host detritus of syn- to post rift events during rift-drift process. The acoustic basement appeared to be faulted with interspaced intrusive bodies. The sections also depicted the presence of slumping of sediments, subsidence, marginal basins, rollover anticlines, mud diapirs etc accompanied by normal to thrust faults related to recent tectonics. Presence of upthrusts in the slope region marks the locations of local compression during collision. Forward gravity modeling constrained with results from seismic and drill results, revealed that the crustal structure beneath the MOB has undergone an extensional type tectonics intruded with intrusive bodies. Results from the seismo-gravity modeling in association with litholog data from drilled wells from the western continental margin of India (WCMI) are presented here.

  1. The late Paleozoic palynological diversity in southernmost Paraná (Uruguay), Claromecó and Paganzo basins (Argentina), Western Gondwana

    Science.gov (United States)

    Beri, Ángeles; Gutiérrez, Pedro R.; Balarino, M. Lucía

    2015-12-01

    This study explores the changes in palynoflora diversity of the late Paleozoic in boreholes DI.NA.MI.GE. 254 (26 samples) and DI.NA.MI.GE. 221 (14 samples) of the Paraná Basin in Uruguay and in 18 surface samples of the La Deheza Formation (Paganzo Basin) and 10 samples of borehole UTAL.CMM1.La Estrella.x-1 (Claromecó Basin) in Argentina. Possible relationships among biostratigraphic zones, diversity levels, facies and climatic evolution patterns in Western Gondwana are studied. Diversity curves of boreholes 221 and 254 and the La Deheza Formation outcrop exhibit similar diversity evolution patterns, i.e., an increase in lower strata diversity and a decrease in upper strata diversity. The disappearance events are determined to be more prominent in biozones of the Cisuralian to the Guadalupian age and less prominent in biozones of the early Cisuralian age. The number of genera raises from the glaciomarine facies, through the deltaic and the marine facies, up to the shallow marine or lagoon facies, in which the disappearance rates become more prominent. . The diversity of the lower part of the La Estrella borehole is lesser than that of the other sequences These diversity, disappearance and appearance behaviors may reflect post-glacial climatic amelioration patterns and the beginning of an arid phase.

  2. An experimental peri-urban basin in North-western France

    Science.gov (United States)

    Chancibault, K.; Rodriguez, F.; Mosini, M.-L.; Furusho, C.; Bocher, E.; Palaccio, M.; Palma-Lopes, S.; Letellier, L.; Benot, R.; Andrieu, H.

    2009-04-01

    Basins located in the suburbs, known as peri-urban basins, face a quick land-use change, increasing pollution and flood risks. Being neither urban nor rural basins, they have been left apart by hydrologists. Improving hydrological models taking into account both natural and anthropogenic surfaces and pathways is the objective of the French project AVuPUR. One of the two peri-urban basins chosen for this project is the Chézine basin, located in northwestern France, in the suburbs of Nantes. The Chézine basin is subject to an oceanic climate and has a quite flat topography. Whereas the upstream part of the catchment remains essentially rural, the urbanization is dense in the downstream part and under development in the medium part. The mean urbanization over the basin is about 18%. A first part of the project consists of collecting geographical and hydrological data, followed by a first hydrological data analysis. Then different spatial segmentation methods are tested based on a geomorphological analysis and ultimately hydrological models well adapted for these particular basins will be developed. Nantes Metropole supplies geographical data as roads, buildings, land-use, sewer networks, Digital Elevation Model, etc. They also have monitored Chézine basin since 2001, with a water level recorder and a rain gauge. The outlet, at the water level recorder, defines a 29 km² basin with a 15km long river. During summer 2008, additional recorders were installed, in the medium part of the basin, at the outlet of the rural subcatchment : a rain gauge and a flow meter. This will help to analyse the hydrological behaviour of the catchment, by characterizing the rainfall spatial variability over the basin and by pointing out the rural surface contribution. In autumn 2008, a geophysical experimental study was carried out, using different geophysical methods: ground penetrating radar, DC-electrical resistivity tomography and EM31 electromagnetic profiling method. The aim of this

  3. The Neogene-Quaternary geodynamic evolution of the central Calabrian Arc: A case study from the western Catanzaro Trough basin

    Science.gov (United States)

    Brutto, F.; Muto, F.; Loreto, M. F.; Paola, N. De; Tripodi, V.; Critelli, S.; Facchin, L.

    2016-12-01

    The Catanzaro Trough is a Neogene-Quaternary basin developed in the central Calabrian Arc, between the Serre and the Sila Massifs, and filled by up to 2000 m of continental to marine deposits. It extends from the Sant'Eufemia Basin (SE Tyrrhenian Sea), offshore, to the Catanzaro Basin, onshore. Here, onshore structural data have been integrated with structural features interpreted using marine geophysical data to infer the main tectonic processes that have controlled the geodynamic evolution of the western portion of the Catanzaro Trough, since Upper Miocene to present. The data show a complex tectonostratigraphic architecture of the basin, which is mainly controlled by the activity of NW-SE and NE-SW trending fault systems. In particular, during late Miocene, the NW-SE oriented faults system was characterized by left lateral kinematics. The same structural regime produces secondary fault systems represented by E-W and NE-SW oriented faults. The ca. E-W lineaments show extensional kinematics, which may have played an important role during the opening of the WNW-ESE paleo-strait; whereas the NE-SW oriented system represents the conjugate faults of the NW-SE oriented structural system, showing a right lateral component of motion. During the Piacenzian-Lower Pleistocene, structural field and geophysical data show a switch from left-lateral to right-lateral kinematics of the NW-SE oriented faults, due to a change of the stress field. This new structural regime influenced the kinematics of the NE-SW faults system, which registered left lateral movement. Since Middle Pleistocene, the study area experienced an extensional phase, WNW-ESE oriented, controlled mainly by NE-SW and, subordinately, N-S oriented normal faults. This type of faulting splits obliquely the western Catanzaro Trough, producing up-faulted and down-faulted blocks, arranged as graben-type system (i.e Lamezia Basin). The multidisciplinary approach adopted, allowed us to constrain the structural setting of

  4. GoAmazon – Scaling Amazon Carbon Water Couplings

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, Manvendra Krishna [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-06

    Forests soak up 25% of the carbon dioxide (CO2) emitted by anthropogenic fossil energy use (10 Gt C y-1) moderating its atmospheric accumulation. How this terrestrial CO2 uptake will evolve with climate change in the 21st century is largely unknown. Rainforests are the most active ecosystems with the Amazon basin storing 120 Gt C as biomass and exchanging 18 Gt C y-1 of CO2 via photosynthesis and respiration and fixing carbon at 2-3 kg C m-2 y-1. Furthermore, the intense hydrologic and carbon cycles are tightly coupled in the Amazon where about half of the water is recycled by evapotranspiration and the other half imported from the ocean by Northeasterly trade winds. Climate models predict a drying in the Amazon with reduced carbon uptake while observationally guided assessments indicate sustained uptake. We will resolve this huge discrepancy in the size and sign of the future Amazon carbon cycle by performing the first simultaneous regional scale high frequency measurements of atmospheric CO2, H2O, HOD, CH4, N2O and CO at the T3 site in Manacupuru, Brazil as part of DOE's GoAmazon project. Our data will be used to inform and develop DOE's CLM on the tropical carbon-water couplings at the appropriate grid scale (10-50km). Our measurements will also validate the CO2 data from Japan's GOSAT and NASA's imminent OCO-2 satellite (launch date July 2014).

  5. Study of ceramics from circular archaeological sites of Amazonic Basin by geochemical methods: dating and characterization; Estudo de ceramicas de sitios arqueologicos circulares da Bacia Amazonica por meio de metodos geoquimicos: datacao e caracterizacao

    Energy Technology Data Exchange (ETDEWEB)

    Nicoli, Ieda Gomes

    2000-09-01

    The aim of this work is to examine by means of characterization and dating pottery recently discovery inside archaeological sites recognized with circular earth structure in Acre State - Brazil which may contribute to the research in the reconstruction of part of the pre-history of the Amazonic Basin. These sites are located mainly in the Hydrographic Basin of High Purus River. Three of them were strategic chosen which provide the ceramics: Lobao, in Sena Madureira County at north; Alto Alegre, in Rio Branco County at east and Xipamanu I, in Xapuri County at south. The X-ray diffraction mineral analysis made possible to identify two types of crystal structures of ceramic minerals: quartz and M-Kaolinite. Neutron activation analysis in conjunction with multivariate statistical methods were applied for the ceramic characterization and classification. An homogeneous group was established by all sherds collected from Alto Alegre and was distinct from all the other two groups analyzed. Some of the sherds collected from Xipamanu I appeared in Lobao's urns, probably because they had the same fabrication process. The Lobao's urns presented a homogeneous group. Geochronology of these materials was carried out by Thermoluminescence. The Xipamanu I was the oldest site and Lobao the youngest. The average age of Xipamanu I and Alto Alegre were 2600 and 2070 years respectively. The average age of of occupation was 400 years to Alto Alegre and 970 years to Xipamanu I. The most probably date for Lobao was 1880 years. (author)

  6. Oblique basin inversion and strain partitioning in back-arc context: example from the Moroccan Alboran Margin (Western Mediterranean)

    Science.gov (United States)

    Lafosse, Manfred; d'Acremont, Elia; Rabaute, Alain; Tomas Vazquez, Juan; Estrada, Ferran; Galindo-Zaldivar, Jesús; Ercilla, Gemma; Alonso, Belén; Gorini, Christian

    2017-04-01

    The Neogene and Quaternary directions of extension recorded in the Mediterranean back-arc basins are oblique to the Africa-Eurasia convergence direction (Jolivet and Faccenna, 2000). In those basins, particularly in the Alboran basin, strike-slip tectonics is favored by the obliquity of coeval extension and compressional deformations, first with a transtensive style that switches to a transpressive mode during the Quaternary. Northwards the Betic Cordillera and southward, the Rifian and the Atlas belts bound the Alboran domain. Transtensional and transpressional episodes deform the Alboran domain and create rotating micro-blocks delimited by a major left lateral NE-SW Miocene transtensional shear zone, a.k.a. the Trans Alboran Shear Zone (TASZ). We present new evidences of strain partitioning affecting the South Alboran Margin (Western Mediterranean) during the end of the Neogene and Quaternary. We use seismic data and high-resolution bathymetry (EM710 multibeam echo sounder) from the MARLBORO-1 (12-channel streamer and Air Gun source), SARAS (single channel Sparker and TOPAS systems) and MARLBORO-2 (single channel Sparker source) surveys. The pre-Messinian deformation and the geometry of the Messinian Erosional Surface (MES) and Plio-Quaternary deposits in the deep basin, developed during a regional extensional back-arc setting, evidence late Miocene to Quaternary folding and left-lateral shearing along the South Alboran Ridge. Around 2.58-1.81 My, the sedimentary shelves of volcanic edifices near the Boudinar and Nekor peripheral sub-basins highlight localized subsidence. At present-day, the NNE-SSW left-lateral Al-Idrissi shear zone delimits westwards the youngest micro-block boundary. Non-cylindrical hinge axes of Pliocene folds are interpreted as evidences of a wrench component of the deformation, which seems maximum to the northern flank of the South Alboran Ridge and decreases toward the Nekor Fault. The observed basin geometries and inversion process could

  7. Source rocks and related petroleum systems of the Chelif Basin, (western Tellian domain, north Algeria)

    NARCIS (Netherlands)

    Arab, Mohamed; Bracène, Rabah; Roure, François; Zazoun, Réda Samy; Mahdjoub, Yamina; Badji, Rabie

    2015-01-01

    In the Chelif basin, the geochemical characterization reveals that the Upper Cretaceous and Messinian shales have a high generation potential. The former exhibits fair to good TOC values ranging from 0.5 to 1.2% with a max. of 7%. The Messinian series show TOC values comprised between 0.5 and 2.3%

  8. Early oceanic opening off Western India-Pakistan margin: The Gop Basin revisited

    Digital Repository Service at National Institute of Oceanography (India)

    Yatheesh, V.; Bhattacharya, G.C.; Dyment, J.

    centre in this region. The prominent but short sequence of fairly linear magnetic anomalies in the Gop Basin does not allow a unique identification; it can be reasonably explained either as A31r-A25r (approx. 69.3-56.4 Ma) or as A29r-A25r (approx. 64...

  9. River Basin Scale Management and Governance: Competing Interests for Western Water

    Science.gov (United States)

    Lindquist, Eric

    2015-04-01

    One of the most significant issues in regard to how social scientists understand environmental and resource management is the question of scale: what is the appropriate scale at which to consider environmental problems, and associated stakeholders (including hydrologists) and their interests, in order to "govern" them? Issues of scale touch on the reality of political boundaries, from the international to the local, and their overlap and conflict across jurisdictions. This presentation will consider the questions of environmental management and governance at the river basin scale through the case of the Boise River Basin (BRB), in southwest Idaho. The river basin scale provides a viable, and generalizable, unit of analysis with which to consider theoretical and empirical questions associated with governance and the role of hydrological science in decision making. As a unit of analysis, the "river basin" is common among engineers and hydrologists. Indeed, hydrological data is often collected and assessed at the basin level, not at an institutional or jurisdictional level. In the case of the BRB much is known from the technical perspective, such as infrastructure and engineering factors, who manages the river and how, and economic perspectives, in regard to benefits in support of major agricultural interests in the region. The same level of knowledge cannot be said about the political and societal factors, and related concepts of institutions and power. Compounding the situation is the increasing probability of climate change impacts in the American West. The geographic focus on the Boise River Basin provides a compelling example of what the future might hold in the American West, and how resource managers and other vested interests make or influence river basin policy in the region. The BRB represents a complex and dynamic environment covering approximately 4,100 square miles of land. The BRB is a highly managed basin, with multiple dams and diversions, and is

  10. Stunting in children under five years old is still a health problem in the Western Brazilian Amazon: a population-based study in Assis Brasil, Acre, Brazil

    Directory of Open Access Journals (Sweden)

    Saulo Augusto Silva Mantovani

    2016-07-01

    Full Text Available Abstract Despite the process of nutritional transition in Brazil, in some places, such as the Amazon region, stunting is still an important public health problem. We identified the prevalence and factors associated with stunting in children under five years old residing in the urban area of Assis Brasil. A survey was conducted in which a questionnaire on socioeconomic, maternal and children’s conditions was applied, and height or length was measured. The children with height for age index below -2 Z-scores were considered stunted, according to the criteria by the World Health Organization. Four hundred and twenty-eight children were evaluated. Of these, 62 were stunted. Factors associated with stunting, according to adjusted models, were: the presence of open sewer, the wealth index for households, the receipt of governmental financial aid and the mother’s height, age and education. Therefore, it was observed that family and the mother’s characteristics as well as environmental and socioeconomic factors were closely related to the occurrence of stunting in the population studied, and such nutritional disturbance is still a health problem in the Brazilian Amazon.

  11. Effects of piping irrigation laterals on selenium and salt loads, Montrose Arroyo Basin, western Colorado

    Science.gov (United States)

    Butler, D.L.

    2001-01-01

    Selenium and salinity are water-quality issues in the Upper Colorado River Basin. Certain water bodies in the lower Gunnison River Basin, including the lower Gunnison River and the Uncompahgre River, exceed the State standard for selenium of 5 micrograms per liter. Remediation methods to reduce selenium and salt loading in the lower Gunnison River Basin were examined. A demonstration project in Montrose Arroyo, located in the Uncompahgre River Basin near Montrose, was done during 1998-2000 to determine the effects on selenium and salt loads in Montrose Arroyo from replacing 8.5 miles of open-ditch irrigation laterals with 7.5 miles of pipe. The participants in the project were the National Irrigation Water Quality Program, the Colorado River Basin Salinity Control Program, the Uncompahgre Valley Water Users Association, and the U.S. Geological Survey. The placing of five laterals in pipe significantly decreased selenium loads in Montrose Arroyo. The selenium load at the outflow monitoring site was about 194 pounds per year less (28-percent decrease) in the period after the laterals were placed in pipe. More than 90 percent of the decrease in selenium load was attributed to a decrease in ground-water load. Salt loads also decreased because of the lateral project, but by a smaller percentage than the selenium loads. The salt load at the outflow site on Montrose Arroyo was about 1,980 tons per year less in the post-project period than in the pre-project period. All of the effects of the demonstration project on selenium and salt loads probably were not measured by this study because some of the lateral leakage that was eliminated had not necessarily discharged to Montrose Arroyo upstream from the monitoring sites. A greater decrease in selenium loads relative to salt loads may have been partially the result of decreases in selenium concentrations in ground water in some areas.

  12. Qualitative Interpretation Of Aerogravity And Aeromagnetic Survey Data Over The South Western Part Of The Volta River Basin Of Ghana

    Directory of Open Access Journals (Sweden)

    George Hinson

    2015-04-01

    Full Text Available Abstract The study area South western part of Volta River Basin of Ghana covering an area of 8570 km2 which is one-eleventh the area of the Volta River basin of Ghana has been subjected to numerous academic research works but geophysical survey works because of virtual perceptive reasons. It is now believed to overly mineral-rich geological structures hence the use of magnetic and gravity survey methods to bring out these mineral-rich geological structures.Geographically it study area is located at the south western part of the Voltaian basin at latitudes 07o 00 N and 08o 00 N and longitudes 02o 00 W and 01o 00 W respectively. Airborne gravity and magnetic survey methods were employed in the data collection. The field data correction and error reduction were applied to the two raw data on the field after which Geosoft Oasis Montaj 7.01 Encom Profile Analysis P.A 11 and 13 Model Vision 12 and ArcGIS 10.0 were used to process enhance e.g. reduce to pole at low latitude first vertical derivative etc. model the reduced and corrected airborne magnetic data and also to produce maps from them data. Low-to-moderate-to-high gravity and magnetic anomalies were obtained in the complete Bouguer anomaly CBA and total magnetic intensity TMI reduced to pole at low latitude with many of these anomalies trending NE-SW by which the Birimian Metasediments and Metavolcanics can be said to be part of the causative structures of these anomalies with cross-cut NW-SE faults. From the quantitative point of view the intrusive granitic bodies of the study area have a mean depth location of 1.7 km while the isolated anomaly is located at a depth of 1.4 km computed from Euler deconvolution. The NE-SW trending anomalies show the trend direction of their causative structures which are the basement rocks and the basinal intrusive bodies.

  13. Neolithic flint mines of Treviño (Basque-Cantabrian Basin, Western Pyrenees, Spain

    Directory of Open Access Journals (Sweden)

    Antonio Tarriño

    2014-09-01

    Full Text Available English:The prehistoric Treviño flint mine complex is located in the Sierra de Araico-Cucho (Berantevilla, Alava - Condado de Treviño, Burgos, inside the lacustrine-palustrine Cenozoic (Aquitanian, Miocene materials of the South-Pyrenean syncline of the Basque-Cantabrian Basin. It is a landscape unit constituted by a set of carbonated layers with abundant nodular and stratiform silicifications. The extraction mining works (often referred to as ‘tailing’ are usually identified as dumps or trenches, subtly visible and associated with archaeological materials.An archaeological excavation was carried out in one potential mining structure (dump or pit that was detected by LiDAR (Light Detection and Ranging in the mountain pass of “Pozarrate” near the villages of Grandival and Araico (Treviño, Burgos. In this work we present the results of the excavation of the last two years. The existence of a Neolithic mining dump (the tailings with a chronology ca. 5000 cal. BC was confirmed. The base rock level with nodular flint was reached and the impressions of the exploited nodules have been identified. As well, the extraction front which reaches about 4.0-5.0 metres in height was delimited. Thousands of lithic remains associated with the extraction and the initial processing (shaping of flint were collected, as along with mining tools. We have found and described three types of mining structures: trenches, linear dumps and crescent-shaped (or “half-moon-shaped” dumps.This site is one of the few prehistoric flint mines dated in the Iberian Peninsula. Recent investigations in the Cantabrian Mountains and Western Pyrenees indicate that the circulation and use of Treviño flint during Prehistory reached many Holocene and Pleistocene archaeological sites, located hundreds of kilometres away from the outcrops.Español:El complejo prehistórico minero de sílex de Treviño se sitúa en la Sierra de Araico-Cucho (Berantevilla, Alava - Condado de Trevi

  14. Closing history of the southern Tianshan oceanic basin, western China: an oblique collisional orogeny

    Science.gov (United States)

    Chen, Chuming; Lu, Huafu; Jia, Dong; Cai, Dongsheng; Wu, Shimin

    1999-02-01

    The Tianshan (Tien Shan) Range is an important Paleozoic collisional orogenic belt and the key to understand the central Asia tectonic evolution. This paper integrates our research results with the existing Chinese and international literature on sedimentology, geochemistry, isotopic geochronology, paleontonology and paleomagnetism of the Tianshan and Tarim regions to propose that the oblique collision may have played an important role in the late Paleozoic closing of the southern Tianshan oceanic basin. As a result of the Sinian (latest Proterozoic, younger than 800 Ma) continental extension and rifting process, the Tarim and Yili blocks separated from their parent continent in the Late Cambrian-Ordovician. The southern Tianshan oceanic crusts between the two blocks subducted northward beneath the southern margin of the Yili block in the Silurian. During the Devonian-Early Carboniferous, the Tarim block rapidly drifted to the north and rotated about 46° clockwise. This process induced the collision of the Yili micro-continent with the eastern segment (present geographical position) of the Tarim continent in the Late Devonian, and the southern Tianshan oceanic crust evolved to be a west-facing remnant oceanic basin. During the Late Carboniferous-Early Permian, the Tarim block, located within an almost constant latitude range, rotated about 26° clockwise with respect to the Yili micro-continent, which ultimately closed the remnant oceanic basin in a `scissors-like' manner from east to west and completed the Tarim-Yili collision. Subsequent A-type subduction of the Tarim continental crust and lithosphere-scale sinistral shearing generated a magmatic arc on the southern margin of the Tarim-Yili suture zone. The Late Permian-Early Triassic clastics deposited in a peripheral foreland basin developed above the arc.

  15. The problems of Paleozoic beds and reconstruction of the Middle Permian sedimentary basin in western Slovenia

    Directory of Open Access Journals (Sweden)

    Ivan Mlakar

    2003-06-01

    Full Text Available In the first part of paper geologic data from smaller outcrops of Val Gardena Formation in west Slovenia are assembled. Together with the already published information from larger outcrops they permit the reconstruction of the Middle Permian sedimentary basin on which the accent of paper is based. Attention is drawn to general problems of Upper Paleozoic beds, and conclusions regarding lithologic, stratigraphic and structural control of uranium and copper deposits in this part of Slovenia are given.

  16. Late Miocene episodic lakes in the arid Tarim Basin, western China.

    Science.gov (United States)

    Liu, Weiguo; Liu, Zhonghui; An, Zhisheng; Sun, Jimin; Chang, Hong; Wang, Ning; Dong, Jibao; Wang, Huanye

    2014-11-18

    The Tibetan Plateau uplift and Cenozoic global cooling are thought to induce enhanced aridification in the Asian interior. Although the onset of Asian desertification is proposed to have started in the earliest Miocene, prevailing desert environment in the Tarim Basin, currently providing much of the Asian eolian dust sources, is only a geologically recent phenomenon. Here we report episodic occurrences of lacustrine environments during the Late Miocene and investigate how the episodic lakes vanished in the basin. Our oxygen isotopic (δ(18)O) record demonstrates that before the prevailing desert environment, episodic changes frequently alternating between lacustrine and fluvial-eolian environments can be linked to orbital variations. Wetter lacustrine phases generally corresponded to periods of high eccentricity and possibly high obliquity, and vice versa, suggesting a temperature control on the regional moisture level on orbital timescales. Boron isotopic (δ(11)B) and δ(18)O records, together with other geochemical indicators, consistently show that the episodic lakes finally dried up at ∼4.9 million years ago (Ma), permanently and irreversibly. Although the episodic occurrences of lakes appear to be linked to orbitally induced global climatic changes, the plateau (Tibetan, Pamir, and Tianshan) uplift was primarily responsible for the final vanishing of the episodic lakes in the Tarim Basin, occurring at a relatively warm, stable climate period.

  17. Late Miocene episodic lakes in the arid Tarim Basin, western China

    Science.gov (United States)

    Liu, Weiguo; Liu, Zhonghui; An, Zhisheng; Sun, Jimin; Chang, Hong; Wang, Ning; Dong, Jibao; Wang, Huanye

    2014-01-01

    The Tibetan Plateau uplift and Cenozoic global cooling are thought to induce enhanced aridification in the Asian interior. Although the onset of Asian desertification is proposed to have started in the earliest Miocene, prevailing desert environment in the Tarim Basin, currently providing much of the Asian eolian dust sources, is only a geologically recent phenomenon. Here we report episodic occurrences of lacustrine environments during the Late Miocene and investigate how the episodic lakes vanished in the basin. Our oxygen isotopic (δ18O) record demonstrates that before the prevailing desert environment, episodic changes frequently alternating between lacustrine and fluvial-eolian environments can be linked to orbital variations. Wetter lacustrine phases generally corresponded to periods of high eccentricity and possibly high obliquity, and vice versa, suggesting a temperature control on the regional moisture level on orbital timescales. Boron isotopic (δ11B) and δ18O records, together with other geochemical indicators, consistently show that the episodic lakes finally dried up at ∼4.9 million years ago (Ma), permanently and irreversibly. Although the episodic occurrences of lakes appear to be linked to orbitally induced global climatic changes, the plateau (Tibetan, Pamir, and Tianshan) uplift was primarily responsible for the final vanishing of the episodic lakes in the Tarim Basin, occurring at a relatively warm, stable climate period. PMID:25368156

  18. Extension of geographic distribution of Chrysobrycon hesperus and C. myersi (Characiformes, Characidae, Stevardiinae for several drainages flowing into the Amazon River Basin in Peru and Colombia Extensión de la distribución geográfica de Chrysobrycon hesperus y C. myersi (Characiformes, Characidae, Stevardiinae para varios drenajes fluyendo hacia la cuenca del Amazonas en Perú y Colombia

    Directory of Open Access Journals (Sweden)

    James Anyelo Vanegas-Ríos

    2013-03-01

    Full Text Available The geographic distribution of Chrysobrycon hesperus (Böhlke and C. myersi Weitzman and Menezes is extended to new localities from the upper Amazon Basin in Peru and Colombia. Chrysobrycon hesperus is recorded for the first time for the Putumayo River Basin in Colombia.Se amplía la distribución geográfica de Chrysobrycon hesperus (Böhlke y C. myersi Weitzman y Menezes para nuevas localidades de la cuenca alta del Amazonas en Perú y Colombia. Chrysobrycon hesperus se registra por primera vez para la cuenca del río Putumayo en Colombia.

  19. Phenotypic characterization of Leishmania spp. causing cutaneous leishmaniasis in the lower Amazon region, western Pará state, Brazil, reveals a putative hybrid parasite, Leishmania (Viannia) guyanensis × Leishmania (Viannia) shawi shawi

    Science.gov (United States)

    Jennings, Yara Lins; de Souza, Adelson Alcimar Almeida; Ishikawa, Edna Aoba; Shaw, Jeffrey; Lainson, Ralph; Silveira, Fernando

    2014-01-01

    We phenotypically characterized 43 leishmanial parasites from cutaneous leishmaniasis by isoenzyme electrophoresis and the indirect immunofluorescence antibody test (23 McAbs). Identifications revealed 11 (25.6%) strains of Leishmania (V.) braziliensis, 4 (9.3%) of L. (V.) shawi shawi, 7 (16.3%) of L. (V.) shawi santarensis, 6 (13.9%) of L. (V.) guyanensis and L. (V.) lainsoni, 2 (4.7%) of L. (L.) amazonensis, and 7 (16.3%) of a putative hybrid parasite, L. (V.) guyanensis/L. (V.) shawi shawi. McAbs detected three different serodemes of L. (V.) braziliensis: I-7, II-1, and III-3 strains. Among the strains of L. (V.) shawi we identified two populations: one (7 strains) expressing the B19 epitope that was previously considered to be species-specific for L. (V.) guyanensis. We have given this population sub-specific rank, naming it L. (V.) s. santarensis. The other one (4 strains) did not express the B19 epitope like the L. (V.) shawi reference strain, which we now designate as L. (V.) s. shawi. For the first time in the eastern Brazilian Amazon we register a putative hybrid parasite (7 strains), L. (V.) guyanensis/L. (V.) s. shawi, characterized by a new 6PGDH three-band profile at the level of L. (V.) guyanensis. Its PGM profile, however, was very similar to that of L. (V.) s. shawi. These results suggest that the lower Amazon region – western Pará state, Brazil, represents a biome where L. (V.) guyanensis and L. (V.) s. shawi exchange genetic information. PMID:25083790

  20. Phenotypic characterization of Leishmania spp. causing cutaneous leishmaniasis in the lower Amazon region, western Pará state, Brazil, reveals a putative hybrid parasite, Leishmania (Viannia guyanensis × Leishmania (Viannia shawi shawi

    Directory of Open Access Journals (Sweden)

    Jennings Yara Lins

    2014-01-01

    Full Text Available We phenotypically characterized 43 leishmanial parasites from cutaneous leishmaniasis by isoenzyme electrophoresis and the indirect immunofluorescence antibody test (23 McAbs. Identifications revealed 11 (25.6% strains of Leishmania (V. braziliensis, 4 (9.3% of L. (V. shawi shawi, 7 (16.3% of L. (V. shawi santarensis, 6 (13.9% of L. (V. guyanensis and L. (V. lainsoni, 2 (4.7% of L. (L. amazonensis, and 7 (16.3% of a putative hybrid parasite, L. (V. guyanensis/L. (V. shawi shawi. McAbs detected three different serodemes of L. (V. braziliensis: I-7, II-1, and III-3 strains. Among the strains of L. (V. shawi we identified two populations: one (7 strains expressing the B19 epitope that was previously considered to be species-specific for L. (V. guyanensis. We have given this population sub-specific rank, naming it L. (V. s. santarensis. The other one (4 strains did not express the B19 epitope like the L. (V. shawi reference strain, which we now designate as L. (V. s. shawi. For the first time in the eastern Brazilian Amazon we register a putative hybrid parasite (7 strains, L. (V. guyanensis/L. (V. s. shawi, characterized by a new 6PGDH three-band profile at the level of L. (V. guyanensis. Its PGM profile, however, was very similar to that of L. (V. s. shawi. These results suggest that the lower Amazon region – western Pará state, Brazil, represents a biome where L. (V. guyanensis and L. (V. s. shawi exchange genetic information.

  1. Drug susceptibility of Plasmodium falciparum in the western Amazon region, state of Acre, Brazil Susceptibilidade a droga, do Plasmodium falciparum, na Amazônia Ocidental, Estado do Acre, Brasil

    Directory of Open Access Journals (Sweden)

    S. Neifer

    1991-06-01

    Full Text Available Field studies in the western Amazon region (state of Acre, Brazil indicate that the 4-aminoquinolines, as well as the combined regimen with sulfadoxine-pyrimethamine, can no longer be recomended for the treatment and prophylaxis of P. falciparum infections in this region. Quinine remains an effective drug when used correctly. However, compliance problems arise due to the often occurring side-effects during a ten day regimen. Prospects of overcoming these constraints by combining a short course of quinine with other drugs are limited, because of the lack of suitable partner compounds. For this reason quinine/clindamycin appears to be a more practical therapy of P. falciparum malaria. In vitro data from this study suggest that mefloquine is another effective alternative for the treatment of falciparum malaria in this Amazon region.Estudos de campo na Amazonia ocidental (Estado do Acre, Brasil indicam que as 4-aminoquinolinas, assim como a sua combinação com sulfadoxina-pirimetamina não podem mais ser recomendadas para o tratamento e profilaxia das infecções pelo P. falciparum nesta região. A quinina permanece como droga efetiva quando usada corretamente. Entretanto, problemas podem surgir devido aos efeitos colaterais durante sua aplicação por período de 10 dias. Possibilidades de ultrapassar estes problemas combinando curto espaço de administração da quinina com outras drogas estão no momento limitadas devido à falta de um composto associado adequado. Por esta razão, a combinação quinina/clindamicina parece ser a terapêutica mais adequada para a malária pelo P. falciparum. Nossos estudos in vitro sugerem que a mefloquina é outra alternativa efetiva para o tratamento da malária falciparum nesta região da Amazônia.

  2. Applicability of laws and regulations of the Brazilian power sector in the Western Amazon; Aplicabilidade das leis e normas do setor eletrico brasileiro nos estados da Amazonia Ocidental

    Energy Technology Data Exchange (ETDEWEB)

    Valois, I.M. [Universidade Federal do Amazonas (UFAM), Manaus, AM (Brazil). Fac. de Tecnologia], E-mail: ivalois@ufam.edu.br; Cartaxo, E.F. [Universidade Federal do Amazonas (NIEMA/UFAM), Manaus, AM (Brazil). Fac. de Tecnologia. Nucleo de Energia, Meio Ambiente e Agua], E-mail: ecartaxo@ufam.edu.br

    2009-07-01

    This analysis is developed within a broad context that is characterized by efficient use of electricity in a region environmentally and socially diverse. It considers that energy efficiency is required throughout the process from generation to power consumption, resulting in an interdisciplinary view of the problems reported here. With this guiding principle, the article analyzes the crises of electricity and makes a historical account of some important legal provisions to the environmental and social problems of the state. It assumes that the applicability of the Electric Sector Legislation, in Amazon, becomes inadequate, once in the depopulated endless area, the solutions do not come, simply, by modern technologies where either the traditional ones have place. Studies carried out by the Federal University of Amazonas bring subsidies to the analysis, which aims to create a forum for discussion about the practice of treating as equal parts of deep diversity. (author)

  3. EVIDENCE FOR LADINIAN (MIDDLE TRIASSIC PLATFORM PROGRADATION IN THE GYULAKESZI AREA, TAPOLCA BASIN, WESTERN HUNGARY: MICROFACIES ANALYSIS AND BIOSTRATIGRAPHY

    Directory of Open Access Journals (Sweden)

    ZSOLT RÓBERT NAGY

    2014-07-01

    Full Text Available A shallowing-upward carbonate sequence was studied from the outcrop at Gyulakeszi, Tapolca Basin (western Hungary, and it is interpreted as a Middle Triassic (Curionii or younger platform progradation. Two lithostratigraphic units are distinguished. Microfacies analysis and micropaleontological investigation conducted on the red nodular, cherty limestone (Vászoly and Buchenstein formations suggest that the lower unit was deposited during the Reitzi and the Secedensis ammonoid zones. The overlying white platform limestone (upper unit is typical of a prograding platform and includes gravity-driven deposits at the base followed by periplatform facies deposited in shallow marine warm waters around the fair-weather wave base. The section at Gyulakeszi was unaffected by fabric-destructive dolomitization, which is uncharacteristic of similar platform facies in the Balaton Highland. Isopachous and radiaxial fibrous calcite cement found in the grainstone and boundstone facies are indicative of early lithification and diagenesis in the marine phreatic zone. “Evinospongiae”-type cement is described for the first time from the Balaton Highland and it is similar to the outer platform cements published previously from the Alps (Italy and Austria. The progradation could have advanced over the pelagic limestones as early as the Curionii zone, which is an undocumented event in the Veszprém Plateau. Similar event, however, is well known from the Western Dolomites, where aggradation was followed by intense progradation during the Gredleri and Archelaus ammonoid zones. The length of this progradation event at Gyulakeszi, however, is ambiguous since proven Ladinian (Longobardian rocks are not exposed in the study area and were not penetrated by boreholes in the Tapolca Basin.

  4. Geochemistry, grouping and origins of crude oils in the Western Pearl River Mouth Basin, offshore South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Huang, B.; Xiao, X.; Zhang, M. [Chinese Academy of Sciences, Guangzhou (China). Guangzhou Institute of Geochemistry

    2003-07-01

    Thirty-seven crude oils and 20 source rocks were selected for detailed molecular geochemical and isotopic analyses in order to establish the genetic relationships between the discovered oils and various petroleum source facies in the Western Pearl River Basin, offshore South China Sea. Four groups of oils were identified. The Group I oils, distributed in the southwestern WC19-1 field of Wenchang B sag, are characterized by high abundance of 4-methyl steranes relative to regular steranes, low abundance of bicadinanes and high {delta}{sup 13}C values, showing good correlation with the medium-deep lacustrine source facies in the Wenchang Formation. The Group II oils represent the majority of the discovered oil reserves in the study area, including those from the Qionghai uplift and the northeast block of the WC19-1 oil field. These oils have moderate concentrations of C{sub 30} 4-methylsteranes, abundant bicadinanes and low values, and correlate well with the shallow lake source facies of the Wenchang Formation in the Wenchang B and A sags. The group III oils, found in the Wenchang A sag and surrounding areas, are devoid of C{sub 30} 4-methylsteranes, with abundant bicadinanes and similar {delta}{sup 13}C values to those of the Group II oils. These characteristics show close affinity with the coal-bearing sequence in the Enping Formation, thus suggesting a coaly source for these oils. The Group IV oils, found only in the WC8-3 field, display intermediate chemical compositions between the Group II and Group III oils, most likely from mixed sources in the Wenchang A sag. These oil-source genetic relationships suggest dominantly short distance oil migration and thus strong source facies controls on the geographic distribution of oil and gas fields within the Western Pearl River Mouth Basin.

  5. Geochemistry, grouping and origins of crude oils in the Western Pearl River Mouth Basin, offshore South China Sea

    Energy Technology Data Exchange (ETDEWEB)

    Baojia Huang; Xianming Xiao [Guangzhou Institute of Geochemistry, Guangdong (China). State Key Laboratory of Organic Geochemistry; Mingqiang Zhang [CNOOC Nanhai West Research Institute, Guangdong (China)

    2003-07-01

    Thirty-seven crude oils and 20 source rocks were selected for detailed molecular geochemical and isotopic analyses in order to establish the genetic relationships between the discovered oils and various petroleum source facies in the Western Pearl River Basin, offshore South China Sea. Four groups of oils were identified. The Group I oils, distributed in the southwestern WC19-1 field of Wenchang B sag, are characterized by high abundance of 4-methyl steranes relative to regular steranes, low abundance of bicadinanes and high {delta}{sup 13}C values, showing good correlation with the medium-deep lacustrine source facies in the Wenchang Formation. The Group II oils represent the majority of the discovered oil reserves in the study area, including those from the Qionghai uplift and the northeast block of the WC19-1 oil field. These oils have moderate concentrations of C{sub 30} 4-methylsteranes, abundant bicadinanes and low {delta}{sup 13}C values, and correlate well with the shallow lake source facies of the Wenchang Formation in the Wenchang B and A sags. The group III oils, found in the Wenchang A sag and surrounding areas, are devoid of C{sub 30} 4-methylsteranes, with abundant bicadinanes and similar {delta}{sup 13}C values to those of the Group II oils. These characteristics show close affinity with the coal-bearing sequence in the Enping Formation thus suggesting a coaly source for these oils. The Group IV oils, found only in the WC8-3 field, display intermediate chemical compositions between the Group II and Group III oils, most likely from mixed sources in the Wenchang A sag. These oil-source genetic relationships suggest dominantly short distance oil migration and thus strong source facies controls on the geographic distribution of oil and gas fields within the Western Pearl River Mouth Basin. (author)

  6. Summer movements of boreal toads (Bufo boreas boreas) in two western Montana basins

    Science.gov (United States)

    David A. Schmetterling; Michael K. Young

    2008-01-01

    The Boreal Toad (Bufo boreas boreas) is widely distributed in the western United States but has declined in portions of its range. Research directed at conserving Boreal Toads has indicated that their movements are largely terrestrial and often limited after the breeding season. We used a combination of stream-based netting, PIT tagging, and radio...

  7. Authigenic carbonates in the sediments of Goa offshore basin, western continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Kocherla, M.

    Euhedral crystals (approx. 1 mm) of authigenic carbonates are identified in 5 m long sediment cores collected from the western continental margin of India in water depths between 2665 and 3070 m. Low-Mg calcite and aragonite are the dominant...

  8. Western Central Asia - Uzbekistan:new insights into the basin architecture and lithosphere structures from geophysical data

    Science.gov (United States)

    Sidorova, Irina

    2014-05-01

    This report was prepared as one part of joint Uzbekistan's Working Group results by DARIUS programme, provided in Uzbekistan during the 2009-2013 years. The special attention is devoted to potential geophysical fields and results of interpretation of seismic profiles, which was the base for conclusions about deep lithosphere structure of the DARIUS domains in Uzbekistan.For four last years 12 field expeditions in Uzbekistan were organized by the DARIUS projects - were studied new geological sections and now the new ideas developing about geodynamical evolution in Western Central Asia. The state of art reveals a very heterogeneous set of data. These data commonly deal either with particular basins or mountain belts, or specific basin investigations. Our aim was to combine all available seismic, magnetic and geothermal data with the revealed of the tectonically objects, geological structures, and to show their interrelated temporal and spatial development for general understanding of the inner structure of lithosphere and upper layers of Earth's crust. In link of this, the detailed studying structure of Paleozoic crystal basement on representative basic sites and the crossing faults, accompained by drawing up of level-by-level and summary sections, large-scale geological and geophysical mapping was conducted. Our study elucidated the lithosphere-scale processes driving forces for kinematic of blocks between southern Tien Shan and Pamir. All our data were integrated in the DARIUS database GEOLIS.

  9. A Systematic Regional Trend in Helium Isotopes Across the NorthernBasin and Range Province, Western North America

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, B. Mack; van Soest, Matthijs C.

    2005-03-22

    An extensive study of helium isotopes in fluids collectedfrom surface springs, fumaroles and wells across the northern Basin andRange Province reveals a systematic trend of decreasing 3He/4He ratiosfrom west to east. The western margin of the Basin and Range ischaracterized by mantle-like ratios (6-8 Ra) associated with active orrecently active crustal magma systems (e.g. Coso, Long Valley, Steamboat,and the Cascade volcanic complex). Moving towards the east, the ratiosdecline systematically to a background value of ~;0.1 Ra. The regionaltrend is consistent with extensive mantle melting concentrated along thewestern margin and is coincident with an east-to-west increase in themagnitude of northwest strain. The increase in shear strain enhancescrustal permeability resulting in high vertical fluid flow rates thatpreserve the high helium isotope ratios at the surface. Superimposed onthe regional trend are "helium spikes", local anomalies in the heliumisotope composition. These "spikes" reflect either local zones of mantlemelting or locally enhanced crustal permeability. In the case of theDixie Valley hydrothermal system, it appears to be a combination ofboth.

  10. Recruitment patterns and growth of high-elevation pines in response to climatic variability (1883–2013), in the western Great Basin, USA

    Science.gov (United States)

    Constance I. Millar; Robert D. Westfall; Diane L. Delany; Alan L. Flint; Lorraine E. Flint

    2015-01-01

    Over the period 1883–2013, recruitment of subalpine limber pine (Pinus flexilis E. James) and Great Basin bristlecone pine (Pinus longaeva D.K. Bailey) above the upper tree line, below the lower tree line, and across middle-elevation forest borders occurred at localized sites across four mountain ranges in the western Great...

  11. Hafnium and neodymium isotopes and REY distribution in the truly dissolved, nanoparticulate/colloidal and suspended loads of rivers in the Amazon Basin, Brazil

    Science.gov (United States)

    Merschel, Gila; Bau, Michael; Schmidt, Katja; Münker, Carsten; Dantas, Elton L.

    2017-09-01

    Radiogenic isotopes in river sediments and river waters have been widely used in provenance studies, as these samples naturally integrate the geology/chemistry of the entire catchment. While the Hf and Nd isotope systems are coupled during igneous processes, they are decoupled during supergene processes at the Earth's surface, which is reflected by the isotope composition of riverine sediments. We present the first data for both Hf and Nd isotope compositions of the dissolved (0.2 μm-filtrates rich in nanoparticles and colloids, NPCs) and the truly dissolved (1 kDa-ultrafiltrates) load of rivers. Hafnium and Nd isotope compositions and concentrations of the Rare Earths and Yttrium (REY) and Hf were determined for suspended particles (>0.2 μm) as well as for the dissolved and the truly dissolved load of the Rio Solimões, the Amazon's largest tributary draining the Andes, and of the Rio Negro, an organic NPC- and particle-rich river draining the rainforest of northern Amazonia. We also analyzed the Nd isotope compositions of suspended sediments and 0.2 μm-filtered water samples from the Amazon River and its tributaries Rio Tapajos, Rio Xingu and Rio Jari. Our novel results clearly show that the decoupling of the Hf and Nd isotope systems is related to incongruent weathering processes on the continent, as this decoupling can already be observed in the different Hf and Nd pools, i.e. in the particulate, the NPC-dominated dissolved and the truly dissolved load of rivers. In the Rio Negro and Rio Solimões, a strong particle size-dependent difference in Hf isotope composition is observed. Values of εHf become more radiogenic as filter poresize decreases, which can be related to the density- and size-dependent distribution of Hf-rich minerals, e.g. zircons, and their absence from the truly dissolved pool. In contrast, the Nd isotope composition of Amazonian river waters reflects that of their catchment geology. Tributaries draining the Precambrian Brazilian and

  12. Modelling basin-wide variations in Amazon forest productivity – Part 1: Model calibration, evaluation and upscaling functions for canopy photosynthesis

    Directory of Open Access Journals (Sweden)

    L. M. Mercado

    2009-07-01

    Full Text Available Given the importance of Amazon rainforest in the global carbon and hydrological cycles, there is a need to parameterize and validate ecosystem gas exchange and vegetation models for this region in order to adequately simulate present and future carbon and water balances. In this study, a sun and shade canopy gas exchange model is calibrated and evaluated at five rainforest sites using eddy correlation measurements of carbon and energy fluxes.

    Results from the model-data evaluation suggest that with adequate parameterisation, photosynthesis models taking into account the separation of diffuse and direct irradiance and the dynamics of sunlit and shaded leaves can accurately represent photosynthesis in these forests. Also, stomatal conductance formulations that only take into account atmospheric demand fail to correctly simulate moisture and CO2 fluxes in forests with a pronounced dry season, particularly during afternoon conditions. Nevertheless, it is also the case that large uncertainties are associated not only with the eddy correlation data, but also with the estimates of ecosystem respiration required for model validation. To accurately simulate Gross Primary Productivity (GPP and energy partitioning the most critical parameters and model processes are the quantum yield of photosynthetic uptake, the maximum carboxylation capacity of Rubisco, and simulation of stomatal conductance.

    Using this model-data synergy, we developed scaling functions to provide estimates of canopy photosynthetic parameters for a range of diverse forests across the Amazon region, utilising the best fitted parameter for maximum carboxylation capacity of Rubisco, and foliar nutrients (N and P for all sites.

  13. Famennian microbial reef facies, Napier and Oscar Ranges, Canning Basin, western Australia

    OpenAIRE

    Stephens, N P; Sumner, Dawn Y.

    2003-01-01

    Following the Frasnian-Famennian mass extinction, which eliminated most skeletal reef-building fauna, the early Famennian reefs of the Canning Basin were constructed primarily by reef-framework microbial communities. In the Napier and Oscar Ranges, the Famennian reef complexes had high-energy, reef-flat depositional environments on a reef-rimmed platform that transitioned into low-energy, deep-water reefs growing in excess of 50 m below sea level. High-energy, reef-flat depositional environme...

  14. Review: Regional groundwater flow modeling in heavily irrigated basins of selected states in the western United States

    Science.gov (United States)

    Rossman, Nathan R.; Zlotnik, Vitaly A.

    2013-09-01

    Water resources in agriculture-dominated basins of the arid western United States are stressed due to long-term impacts from pumping. A review of 88 regional groundwater-flow modeling applications from seven intensively irrigated western states (Arizona, California, Colorado, Idaho, Kansas, Nebraska and Texas) was conducted to provide hydrogeologists, modelers, water managers, and decision makers insight about past modeling studies that will aid future model development. Groundwater models were classified into three types: resource evaluation models (39 %), which quantify water budgets and act as preliminary models intended to be updated later, or constitute re-calibrations of older models; management/planning models (55 %), used to explore and identify management plans based on the response of the groundwater system to water-development or climate scenarios, sometimes under water-use constraints; and water rights models (7 %), used to make water administration decisions based on model output and to quantify water shortages incurred by water users or climate changes. Results for 27 model characteristics are summarized by state and model type, and important comparisons and contrasts are highlighted. Consideration of modeling uncertainty and the management focus toward sustainability, adaptive management and resilience are discussed, and future modeling recommendations, in light of the reviewed models and other published works, are presented.

  15. Dominant Large-Scale Atmospheric Circulation Systems for the Extreme Precipitation over the Western Sichuan Basin in Summer 2013

    Directory of Open Access Journals (Sweden)

    Yamin Hu

    2015-01-01

    Full Text Available The western Sichuan Basin (WSB is a rainstorm center influenced by complicated factors such as topography and circulation. Based on multivariable empirical orthogonal function technique for extreme precipitation processes (EPP in WSB in 2013, this study reveals the dominant circulation patterns. Results indicate that the leading modes are characterized by “Saddle” and “Sandwich” structures, respectively. In one mode, a TC from the South China Sea (SCS converts into the inverted trough and steers warm moist airflow northward into the WSB. At the same time, WPSH extends westward over the Yangtze River and conveys a southeasterly warm humid flow. In the other case, WPSH is pushed westward by TC in the Western Pacific and then merges with an anomalous anticyclone over SCS. The anomalous anticyclone and WPSH form a conjunction belt and convey the warm moist southwesterly airflow to meet with the cold flow over the WSB. The configurations of WPSH and TC in the tropic and the blocking and trough in the midhigh latitudes play important roles during the EPPs over the WSB. The persistence of EPPs depends on the long-lived large-scale circulation configuration steady over the suitable positions.

  16. The new occurrence of Marinoan cap carbonate in Brazil: The expansion of snowball Earth events to the southwesternmost Amazon Craton

    Science.gov (United States)

    Gaia, Valber do Carmo de Souza; Nogueira, Afonso César Rodrigues; Domingos, Fábio Henrique Garcia; Sans-Jofre, Pierre; Bandeira, José Cavalcante da Silva; Oliveira, José Guilherme Ferreira de; Sial, Alcides Nóbrega

    2017-07-01

    Carbonate deposits exposed in the border of the Pimenta Bueno and Colorado grabens, western part of Parecis Basin, southwestern Amazon Craton, Brazil, have been previously considered as Paleozoic record. These deposits lying unconformably on Mesoproterozoic crystalline rocks, the basement of the grabens, and consist predominantly by pinkish dolomite overlying glacial diamictites, with average negative values of δ13C of -3,10‰VPDB. The contact between the dolostone and diamictites is sharp and deformed similarly with others Neoproterozoic cap carbonates occurrences in the Amazon Craton, also related to the Marinoan Glaciation (635 Ma). This new occurrence of Marinoan cap carbonate is composed by two facies associations. Facies Association 1 consists of pinkish peloidal dolostone with even parallel and quasi-planar laminations, wavy and megarriple bedding, macropeloid lenses associated with low-angle truncations, interpreted as fairwhether- and storm-influenced shallow platform deposits. Facies association 2 consists in dolostone rhythmically interbedded with shale underlaid by 5 m-thick laminated siltstones, interpreted as moderately deep platform deposits. This retrogradational succession is overlaid in angular unconformity by Early Paleozoic diamictites and locally by Mesozoic volcanic rocks. This cap carbonate precedes the Paleozoic deposits of Parecis Basin and represents a post-glacial event linked to the Marinoan glaciation, extending to the southwesternmost Amazon Craton the phenomena of the Snowball Earth hypothesis.

  17. ENVIRONMENTS AND FAUNAL PATTERNS IN THE KACHCHH RIFT BASIN, WESTERN INDIA, DURING THE JURASSIC

    Directory of Open Access Journals (Sweden)

    FRANZ THEODOR FÜRSICH

    2004-03-01

    Full Text Available Marine Jurassic sediments (Bajocian-Tithonian of the Kachchh Basin were deposited in a ramp setting. Except during the Middle and Late Bathonian, when a carbonate regime became established, the fill of the basin consists predominantly of siliciclastics. The sediments represent environments that range from coastal plains (rivers and associated flood plains with caliche nodules, deltas, brackish water lagoons, nearshore sand and iron-oolite bars of the inner ramp, generally situated above fair-weather wave-base, to the middle ramp influenced by storm-waves and by storm-generated currents, and finally to the outer ramp which is characterised by low energy, fine-grained sediments. Changes in relative sea level produced a cyclic sedimentation pattern. The rich benthic fauna of macroinvertebrates is dominated by bivalves, followed by brachiopods, gastropods, corals, serpulids, and sponges. The analysis of 370 statistical samples and more than 27, 000 specimens produced more than 40 benthic associations and assemblages. They show a relationship to several environmental parameters, two of which, salinity and climate, are briefly discussed. The spatial distribution of the facies and biota is outlined for two time slices, the Bathonian and the Callovian-Oxfordian, respectively.

  18. Amazon soils : a reconnaissance of the soils of the Brazilian Amazon region

    NARCIS (Netherlands)

    Sombroek, W.G.

    1966-01-01

    The study deals with soils of the Brazilian part of the Amazon basin. Most soils are Latosols, some with soft or hardened plinthite. The Latosols are characterized by a latosolic B horizon as defined in Brazil.

    Plinthite, its formation and morphology were extensively described. Five main

  19. Regional and Local Controls on the Distribution of Geothermal Systems in the Great Basin, Western United States

    Science.gov (United States)

    Coolbaugh, M. F.; Blewitt, G.; Faulds, J. E.; Kreemer, C. W.

    2005-12-01

    In the Great Basin (GB) of the western United States, geothermal systems with reservoir temperatures in excess of 150 C can be classified into two main categories (magmatic and amagmatic) according to the presence or absence of shallow magmatic heat sources. Magmatic systems are restricted to the margins of the GB where they are closely associated with Quaternary silicic volcanic rocks, whereas amagmatic systems occur over a large portion of the Great Basin interior and are not spatially associated with young silicic volcanism. A tabulation of temperature gradients for known geothermal systems in the world confirms research by others indicating that both magmatic and amagmatic systems occur within areas of high temperature gradients and high heat flow. However, high heat flow alone is not sufficient to explain the abundance of high-temperature geothermal activity in the GB interior. While the distribution of favorable host rocks likely plays a role, active crustal tectonics appears instrumental in explaining patterns of geothermal activity. At a detailed scale, Quaternary faults control the location of most geothermal systems in the GB. However, hundreds of Quaternary faults are distributed throughout the GB, and most do not host high-temperature geothermal resources. Spatial statistical analysis demonstrates that high-temperature geothermal systems (more than 150 C) are preferentially associated with NE-striking Quaternary faults, which in turn are oriented roughly perpendicular to the current direction of crustal extension in the western GB. Maps of active crustal extension rates in the GB, derived from Global Positioning System (GPS) velocity measurements and estimated slip rates on Quaternary faults, correlate well with the distribution of high-temperature geothermal systems and help explain why some faults with lower slip rates or unfavorable orientations don't host geothermal activity. Many geothermal systems in the GB occur in a broad transitional region

  20. Climate inferences between paleontological, geochemical, and geophysical proxies in Late Pleistocene lacustrine sediments from Summer Lake, Oregon, western Great Basin

    Science.gov (United States)

    Heaton, Eric; Thompson, Greg; Negrini, Rob; Wigand, Peter

    2016-04-01

    Paleontological, geochemical, and geophysical data from western Great Basin pluvial Summer Lake, Oregon have established a high resolution paleoclimate record during the late Pleistocene Mono Lake Excursion (~34.75 ka), Dansgaard-Oeschger interstadials 6-8, and the end of Heinrich Even 4 (~38 ka). Proxies of grain-size, magnetic susceptibility, carbon/nitrogen ratio, ostracode analysis and palynology from a depocenter core show new results with improved age control regarding high amplitude, high frequency changes in lake level, lake temperature, and regional precipitation and temperature which correspond directly with colder/warmer and respectively drier/wetter climates as documented with Northern Atlantic Greenland ice core data. Results from geophysical and geochemical analysis, and the presence of ostracode Cytherissa lacustris consistently demonstrate the correspondence of low lake conditions and colder water temperatures during Dansgaard-Oeschger stadials and the Mono Lake Excursion. The opposite holds true during interstadials. Smaller grain size, increases in carbon/nitrogen ratio and consistent absence of C. lacustris suggest periods of increased discharge into the lake, increased lake level, and warmer water temperatures. Warmer/wetter climate conditions are confirmed during interstadials 7 and 8 from pollen analysis. Existence of Atriplex, Rosaceae, Chrysothamnus and Ambrosia, and pollen ratios of Juniperus/Dip Pinus and (Rosaceae+Atriplex+Poaceae+Chrysothamnus+Ambrosia)/(Pinus+Picea+T. mertensiana+Sarcobatus) suggest warmer/wetter semi-arid woodland conditions during interstadials 7 and 8. This contrasts with absences in these pollens and pollen ratios indicating colder/drier continental montane woodland conditions during stadials and the Mono Lake Excursion. Increases in Juniper/Dip Pinus ratio suggest a warmer/wetter climate during interstadial 6 however additional proxies do not demonstrate comparative warmer/wetter climate, deeper lake level or

  1. Shallow lacustrine system of the Permian Pedra de Fogo Formation, Western Gondwana, Parnaíba Basin, Brazil

    Science.gov (United States)

    Araújo, Raphael Neto; Nogueira, Afonso César Rodrigues; Bandeira, José; Angélica, Rômulo Simões

    2016-04-01

    The Permian Period of the Parnaíba Basin, northern Brazil, represented here by deposits from the Pedra de Fogo Formation, records important events that occurred in Western Gondwana near its boundary with the Mesozoic Era. The analysis of outcrop based facies from the Permian Pedra de Fogo Formation, which is 100 m thick, carried out along the eastern and western borders of the Parnaiba Basin, allowed the identification of eleven sedimentary facies, which were grouped into three distinct facies associations (FA), representative of a shallow lacustrine system associated with mudflats and ephemeral rivers. Bioturbation, desiccation cracks, silcretes and various siliceous concretions characterize the Pedra de Fogo deposits. The FA1 mudflat deposits occur predominantly at the base of the Pedra de Fogo Formation and consist of laminated claystone/mudstone, mudcrack-bearing sandstones/mudstones and sandstones exhibiting cross-lamination, massive and megaripple bedding. Popcorn-like silicified nodules and casts indicate evaporite deposits. Other common features are silica concretions, silicified tepees and silcretes. FA2 represents nearshore deposits and consists of fine-grained sandstones with evenly parallel lamination, climbing ripple cross-lamination, massive and megaripple bedding and mudstone/siltstone showing evenly parallel lamination. FA3 refers to wadi/inundite deposits, generally organized as fining-upward cycles of metric size, composed of conglomerates and medium-grained pebbly sandstones showing massive bedding and cross-stratification, as well as claystone/siltstone showing evenly parallel to undulate lamination. Scour-and-fill features are isolated in predominantly tabular deposits composed of mudstones interbedded with fine to medium-grained sandstones showing planar to slightly undulate lamination. Silicified plant remains previously classified as belonging to the Psaronius genus found in the uppermost levels of the Pedra de Fogo Formation, near the

  2. Ethnoichthyological contribution to the official fisheries document concerning fisheries closure of some commercial fish categories in the western Brazilian Amazon, Guaporé River, Rondônia, Brazil

    Directory of Open Access Journals (Sweden)

    Suelen Taciane Brasil de Souza

    2008-06-01

    Full Text Available There are conflicts among fishermen and local environmental protection agencies that regulate fishing in the area, concerning the official closure periods of the fisheries. The fishermen affirm that the dates established for protection of spawning do not correspond to the spawning season of the primary commercialized species, and that this could be hindering the local fish markets. This report compares the traditional ecological knowledge (TEK with information obtained from experimental fishery and scientific data covering the reproduction periods of the primary categories of fish market in the region. Of the 28 fish categories analyzed, 14 (50% were captured in experimental fishing and were evaluated. The TEK confirmed the experimental information for 10 categories of fish (72%. The results suggest the necessity of adjusting the official protection dates stipulated for the following fish categories: caparari (Pseudoplatystoma tigrinun, Sorubim (P. fasciatum, tambaqui (Colossoma macropomum, pescada (Plagioscion squamosissimus and tucunaré (Cichla ocellaris. The discussion deals with a possibly inadequate period of protection based on the information obtained from different basins applied to larger and more diverse areas of the Brazilian Amazon Rainforest. This study confirms the refined biological knowledge that the fishermen have of the species they exploit and suggests that the traditional ecological knowledge can be useful to adjust political issues dealing with the regional protection agency of fishing.

  3. The Amazon forest-rainfall feedback: the roles of transpiration and interception

    Science.gov (United States)

    Dekker, Stefan; Staal, Arie; Tuinenburg, Obbe

    2017-04-01

    In the Amazon, deep-rooted trees increase local transpiration and high tree cover increase local interception evaporation. These increased local evapotranspiration fluxes to the atmosphere have both positive effects on forests down-wind, as they stimulate rainfall. Although important for the functioning of the Amazon, we have an inadequate assessment on the strength and the timing of these forest-rainfall feedbacks. In this study we (i) estimate local forest transpiration and local interception evaporation, (ii) simulate the trajectories of these moisture flows through the atmosphere and (iii) quantify their contributions to the forest-rainfall feedback for the whole Amazon basin. To determine the atmospheric moisture flows in tropical South America we use a Lagrangian moisture tracking algorithm on 0.25° (c. 25 km) resolution with eight atmospheric layers on a monthly basis for the period 2003-2015. With our approach we account for multiple re-evaporation cycles of this moisture. We also calculate for each month the potential effects of forest loss on evapotranspiration. Combined, these calculations allow us to simulate the effects of land-cover changes on rainfall in downwind areas and estimate the effect on the forest. We found large regional and temporal differences in the importance how forest contribute to rainfall. The transpiration-rainfall feedback is highly important during the dry season. Between September-November, when large parts of the Amazon are at the end of the dry season, more than 50% of the rainfall is caused by the forests upstream. This means that droughts in the Amazon are alleviated by the forest. Furthermore, we found that much moisture cycles several times during its trajectory over the Amazon. After one evapotranspiration-rainfall cycle, more than 40% of the moisture is re-evaporated again. The interception-evaporation feedback is less important during droughts. Finally from our analysis, we show that the forest-rainfall feedback is

  4. Regional nitrous oxide flux in Amazon basin; Estudo de fluxo de oxido nitroso (N{sub 2}O) regional na Bacia Amazonica

    Energy Technology Data Exchange (ETDEWEB)

    Felippe, Monica Tais Siqueira D' Amelio

    2010-07-01

    Nitrous oxide (N{sub 2}O) is the third most important anthropogenic greenhouse gas. Globally, the main sources of N{sub 2}O are nitrification and denitrification in soils. About two thirds of the soil emissions occur in the tropics and approximately 20% originate in wet rain forest ecosystems, like the Amazon forest. The work presented here involves aircraft vertical profiles of N{sub 2}O from the surface to 4 km over two sites in the Eastern and Central Amazon: Tapajos National Forest (2000-2009) and Cuieiras Biologic Reserve (2004-2007), and the estimation of N{sub 2}O fluxes for regions upwind of these sites using two methods: Column Integration Technique and Inversion Model - FLEXPART. To our knowledge, these regional scale N{sub 2}O measurements in Amazonia are unique and represent a new approach to looking regional scale emissions. For the both methods, the fluxes upwind of Cuieiras Biologic Reserve exhibited little seasonality, and the annual mean was 1.9 {+-}1.6 mgN{sub 2}Om{sup -2}day{sup -1} for the Column Integration Technique and 2.3{+-}0.9 mgN{sub 2}Om{sup -2}day{sup -1} for Inversion Model - FLEXPART. For fluxes upwind of Tapajos Nacional Forest, the Inversion Model - FLEXPART presented about half (0.9{+-}1.7 mgN{sub 2}Om{sup -2}day{sup -1}) of the Column Integration Technique (2.0{+-}1.1 mgN{sub 2}Om{sup -2}day{sup -1}) for the same period (2004-2008). One reason could be because the inversion model does not consider anthropic activities, once it had a good representation for less impacted area. Both regions presented similar emission during wet season. By Column Integration Technique, fluxes upwind Tapajos Nacional Forest were similar for dry and wet seasons. The dry season N{sub 2}O fluxes exhibit significant correlations with CO fluxes, indicating a larger than expected source of N{sub 2}O from biomass burning. The average CO:N{sub 2}O ratio for all 38 profiles sampled during the dry season was 82{+-}69 mol CO:molN{sub 2}O and suggests a larger

  5. Geochemistry of some deep gold mine waters from the western portion of the Witwatersrand Basin, South Africa

    Science.gov (United States)

    Duane, M. J.; Pigozzi, G.; Harris, C.

    1997-02-01

    A suite of 12 mine water samples within the Witwatersrand Basin (South Africa) were analysed for trace element concentrations, strontium isotopic composition and stable isotopes (O and H). Chemical profiles for four Au mines (Western Deep Levels, Vaal Reefs, Freddies and President Steyn) are used to infer origin, chemical and isotopic evolution of the brines and for comparison with basement brines from other Precambrian areas. Systematic relationships are observed between {87Sr}/{86Sr} and {1}/{Sr} : two major mixing trends are required to explain the range of very radiogenic end-members. Possible end-members for the two components could be (1) {87Sr}/{86Sr} = 0.7251 , Sr concentration = 0.12 mg l -1 from a Vaal Reefs compartment and {87Sr}/{86Sr} = 0.7694 , Sr = 39.3 mg l -1 from a Freddies compartment. (2) {87Sr}/{86Sr} = 0.7251 , Sr = 0.12 mg l -1 (as above) with a {87Sr}/{86Sr} = 0.7404 , Sr = 745 mg l -1 from Western Deep Levels. Strontium isotope ratios range above those expected for present-day seawater and are even higher than some locally-derived low Rb minerals from the Precambrian basement. The brines acquired radiogenic 87Sr through interaction with granitic basement (Kaapvaal Craton), shales of the Central Rand Group (in particular Ventersdorp Contact Reef), siliclastics within the West Rand Group and particularly with dolomites from the overlying Transvaal Supergroup. In order to obtain their multielement and radiogenic isotope signatures the meteoric waters descended through fractured rocks between the main dykes and faults (example: Oberholzer and Bank Dyke at Western Deep Levels). They slowly interacted with Au bearing conglomerates and quartzites of the West Rand Group. The inverse relationship between Sr isotope composition and precious/heavy metal concentration suggests fluid/rock interaction within the shales and volcanics of the Ventersdsorp Contact Reef (high in Au and total organic carbon [TOC], less radiogenic strontium composition by

  6. Aeolian sands in continental red beds of the Middle Buntsandstein (Lower Triassic) at the western margin of the German Basin

    Science.gov (United States)

    Mader, Detlef

    1982-04-01

    Aeolian sands occur widespread in continental red beds of the Middle Buntsandstein (Lower Triassic) at the western margin of the German Basin (Middle Europe), in the Eifel area. Cross-bedded sands were mainly deposited by grainfall on lee-slopes of barchanoid-type dunes in unimodal wind regime in both low-energy and high-energy environments. Occasionally, sets are internally truncated by reactivation surfaces. Crest height of solitary-set dunes varies in the range of some meters. Locally, sequences of cosets, both of tabular-planar and wedge-planar type, capped by flat or gently windward dipping topset beds, represent larger dune complexes of about 10-20 m in height and at least 80-100 m in lateral extent. Horizontal-laminated deposits originated as sand sheets in interdune areas. The dune sands were deposited by trade winds of the northern hemisphere in low palaeolatitude, predominantly by southeasterly and southwesterly trade winds in summer when the intertropical convergence zone was shifted to the north. Aeolian sands built up an extensive dune belt in the Eifel, intersected by braided to anastomosing rivers. Fluviatile incursions or heavy ephemeral rainfall led to aquatic redeposition of aeolian sediments and origin of shallow lakes in interdune depressions. Distribution of aeolian and fluviatile sediments in Karlstal-Schichten is different in the Southern, Western and Northern Eifel. Middle Buntsandstein sequence in the Southern Eifel reflects an evolution of the fluviatile depositional environment also incorporating the occurrence and distribution of aeolian sands. Evolution is characterized by increasing spacing and sinuosity of channels, weakening supply of coarse detritus from the source areas and decreasing braiding of the river systems. Aeolian sands occur in the final phase of this evolution which led from local alluvial fans via cobbly and pebbly braided rivers to sandy braided streams and finally to an intertonguing of aeolian dunes and braided to

  7. Source to sink: Evolution of lignin composition in the Madre de Dios River system with connection to the Amazon basin and offshore

    Science.gov (United States)

    Feng, Xiaojuan; Feakins, Sarah J.; Liu, Zongguang; Ponton, Camilo; Wang, Renée. Z.; Karkabi, Elias; Galy, Valier; Berelson, William M.; Nottingham, Andrew T.; Meir, Patrick; West, A. Joshua

    2016-05-01

    While lignin geochemistry has been extensively investigated in the Amazon River, little is known about lignin distribution and dynamics within deep, stratified river channels or its transformations within soils prior to delivery to rivers. We characterized lignin phenols in soils, river particulate organic matter (POM), and dissolved organic matter (DOM) across a 4 km elevation gradient in the Madre de Dios River system, Peru, as well as in marine sediments to investigate the source-to-sink evolution of lignin. In soils, we found more oxidized lignin in organic horizons relative to mineral horizons. The oxidized lignin signature was maintained during transfer into rivers, and lignin was a relatively constant fraction of bulk organic carbon in soils and riverine POM. Lignin in DOM became increasingly oxidized downstream, indicating active transformation of dissolved lignin during transport, especially in the dry season. In contrast, POM accumulated undegraded lignin downstream during the wet season, suggesting that terrestrial input exceeded in-river degradation. We discovered high concentrations of relatively undegraded lignin in POM at depth in the lower Madre de Dios River in both seasons, revealing a woody undercurrent for its transfer within these deep rivers. Our study of lignin evolution in the soil-river-ocean continuum highlights important seasonal and depth variations of river carbon components and their connection to soil carbon pools, providing new insights into fluvial carbon dynamics associated with the transfer of lignin biomarkers from source to sink.

  8. Karyotype characterization and ZZ/ZW sex chromosome heteromorphism in two species of the catfish genus Ancistrus Kner, 1854 (Siluriformes: Loricariidae from the Amazon basin

    Directory of Open Access Journals (Sweden)

    Renildo R. de Oliveira

    Full Text Available We present karyotypic characteristics and report on the occurrence of ZZ/ZW sex chromosomes in Ancistrus ranunculus (rio Xingu and Ancistrus sp. "Piagaçu" (rio Purus, of the Brazilian Amazon. Ancistrus ranunculus has a modal number of 2n=48 chromosomes, a fundamental number (FN of 82 for both sexes, and the karyotypic formula was 20m+8sm+6st+14a for males and 19m+9sm+6st+14a for females. Ancistrus sp. "Piagaçu" presented 2n=52 chromosomes, FN= 78 for males and FN= 79 for females. The karyotypic formula was 16m+8sm+2st+26a for males and 16m+9sm+2st+25a for females. The high number of acrocentric chromosomes in karyotype of Ancistrus sp. "Piagaçu" differs from the majority of Ancistrini genera studied so far, and may have resulted from pericentric inversions and translocations. The lower number of chromosomes in A. ranunculus indicates that centric fusions also occurred in the evolution of Ancistrus karyotypes. We conclude that karyotypic characteristics and the presence of sex chromosomes can constitute important cytotaxonomic markers to identify cryptic species of Ancistrus. However, sex chromosomes apparently arose independently within the genus and thus do not constitute a reliable character to analyze phylogenetic relations among Ancistrus species.

  9. Analysis of Critical Permeabilty, Capillary Pressure and Electrical Properties for Mesaverde Tight Gas Sandstones from Western U.S. Basins

    Energy Technology Data Exchange (ETDEWEB)

    Alan Byrnes; Robert Cluff; John Webb; John Victorine; Ken Stalder; Daniel Osburn; Andrew Knoderer; Owen Metheny; Troy Hommertzheim; Joshua Byrnes; Daniel Krygowski; Stefani Whittaker

    2008-06-30

    Although prediction of future natural gas supply is complicated by uncertainty in such variables as demand, liquefied natural gas supply price and availability, coalbed methane and gas shale development rate, and pipeline availability, all U.S. Energy Information Administration gas supply estimates to date have predicted that Unconventional gas sources will be the dominant source of U.S. natural gas supply for at least the next two decades (Fig. 1.1; the period of estimation). Among the Unconventional gas supply sources, Tight Gas Sandstones (TGS) will represent 50-70% of the Unconventional gas supply in this time period (Fig. 1.2). Rocky Mountain TGS are estimated to be approximately 70% of the total TGS resource base (USEIA, 2005) and the Mesaverde Group (Mesaverde) sandstones represent the principal gas productive sandstone unit in the largest Western U.S. TGS basins including the basins that are the focus of this study (Washakie, Uinta, Piceance, northern Greater Green River, Wind River, Powder River). Industry assessment of the regional gas resource, projection of future gas supply, and exploration programs require an understanding of reservoir properties and accurate tools for formation evaluation. The goal of this study is to provide petrophysical formation evaluation tools related to relative permeability, capillary pressure, electrical properties and algorithms for wireline log analysis. Detailed and accurate moveable gas-in-place resource assessment is most critical in marginal gas plays and there is need for quantitative tools for definition of limits on gas producibility due to technology and rock physics and for defining water saturation. The results of this study address fundamental questions concerning: (1) gas storage; (2) gas flow; (3) capillary pressure; (4) electrical properties; (5) facies and upscaling issues; (6) wireline log interpretation algorithms; and (7) providing a web-accessible database of advanced rock properties. The following text

  10. Geophysical evidence and inferred triggering factors of submarine landslides on the western continental margin of the Ulleung Basin, East Sea

    Science.gov (United States)

    Cukur, Deniz; Kim, Seong-Pil; Kong, Gee-Soo; Bahk, Jang-Jun; Horozal, Senay; Um, In-Kwon; Lee, Gwang-Soo; Chang, Tae-Soo; Ha, Hun-Jun; Völker, David; Kim, Jung-Ki

    2016-12-01

    Submarine landslides form very complex depositional and erosional features on the seafloor, and their dynamics and triggering processes are yet to be understood completely. Numerous studies are being undertaken both because of the scientific significance but also for their potential harm to seafloor infrastructure and coastal areas. This study investigates the styles and causes of landsliding along the western margin of the Ulleung Basin in the East Sea, based on multiple sparker, subbottom profiler, multibeam echosounder and sediment core datasets collected in 2015. The bathymetric analyses indicate that the southern slope of the Ulleung Basin has experienced at least seven submarine failures. These failures left clear arcuate-shaped scarps that initiated at water depths of 600 m. The observed headwall scarps have heights that exceed 60 m and appear to be the result of retrogressive-type failures. Seismic reflection data clearly image the basal sliding surface that is characterized by a prominent high-amplitude reflector. Chaotic-to-transparent seismic facies occur immediately downslope of the headwall scarps; these represent 20 m thick landslide deposits. Gravity cores taken from areas adjacent to the scars suggest that these slides are older than ca. 97 ka. Interpretation of the present data shows that faults appear to cut recent sediments upslope of scarps, and that the slope may still be in an active phase of failure. Seismic data also image various overpressurized gases and/or gas fluids, as evidenced by the occurrence of pockmarks and seismic chimneys in upslope or adjacent areas of the scarps. Hence, earthquakes associated with tectonic activity and development of fluid overpressure may have acted as the main conditioning factor for destabilizing the slope sediments. Geotechnical stability analyses indicate that the sampled slope sediments are exceptionally stable under present-day conditions, even under seismic loading. This finding points to additional

  11. Modeling of extreme freshwater outflow from the north-eastern Japanese river basins to western Pacific Ocean

    Science.gov (United States)

    Troselj, Josko; Sayama, Takahiro; Varlamov, Sergey M.; Sasaki, Toshiharu; Racault, Marie-Fanny; Takara, Kaoru; Miyazawa, Yasumasa; Kuroki, Ryusuke; Yamagata, Toshio; Yamashiki, Yosuke

    2017-12-01

    This study demonstrates the importance of accurate extreme discharge input in hydrological and oceanographic combined modeling by introducing two extreme typhoon events. We investigated the effects of extreme freshwater outflow events from river mouths on sea surface salinity distribution (SSS) in the coastal zone of the north-eastern Japan. Previous studies have used observed discharge at the river mouth, as well as seasonally averaged inter-annual, annual, monthly or daily simulated data. Here, we reproduced the hourly peak discharge during two typhoon events for a targeted set of nine rivers and compared their impact on SSS in the coastal zone based on observed, climatological and simulated freshwater outflows in conjunction with verification of the results using satellite remote-sensing data. We created a set of hourly simulated freshwater outflow data from nine first-class Japanese river basins flowing to the western Pacific Ocean for the two targeted typhoon events (Chataan and Roke) and used it with the integrated hydrological (CDRMV3.1.1) and oceanographic (JCOPE-T) model, to compare the case using climatological mean monthly discharges as freshwater input from rivers with the case using our hydrological model simulated discharges. By using the CDRMV model optimized with the SCE-UA method, we successfully reproduced hindcasts for peak discharges of extreme typhoon events at the river mouths and could consider multiple river basin locations. Modeled SSS results were verified by comparison with Chlorophyll-a distribution, observed by satellite remote sensing. The projection of SSS in the coastal zone became more realistic than without including extreme freshwater outflow. These results suggest that our hydrological models with optimized model parameters calibrated to the Typhoon Roke and Chataan cases can be successfully used to predict runoff values from other extreme precipitation events with similar physical characteristics. Proper simulation of extreme

  12. Aerosol optical properties of Western Mediterranean basin from multi-year AERONET data

    Science.gov (United States)

    Benkhalifa, Jamel; Léon, Jean François; Chaabane, Mabrouk

    2017-11-01

    Aerosol optical properties including the total and coarse mode aerosol extinction optical depth (AODt and AODc respectively), Angstrom exponent (AE), size distribution, single scattering albedo (SSA) were examined using long-term ground-based radiometric measurements at 9 sites in the Western Mediterranean: Oujda, Malaga, Barcelona, Carpentras, Rome Tor Vergata, Ersa, Ispra, Venice and Evora, during the 4-year study period (2010-2013). The South-North gradient in the fraction of AODc represents the signature of the increasing influence of coarse particles on the optical properties at southern stations. This fraction has a daily mean ranging from 48 ± 18% at the southern site Oujda and to 8 ± 8% at Ispra. The low average AE444-870 value (affected by such dust events in the following days.

  13. Three-Dimensional Geothermal Fairway Mapping: Examples From the Western Great Basin, USA

    Energy Technology Data Exchange (ETDEWEB)

    Siler, Drew L. [Univ. of Nevada, Reno, NV (United States). Nevada Bureau of Mines and Geology; Faulds, James E. [Univ. of Nevada, Reno, NV (United States). Nevada Bureau of Mines and Geology

    2013-09-29

    Elevated permeability along fault systems provides pathways for circulation of geothermal fluids. Accurate location of such fluid flow pathways in the subsurface is crucial to future geothermal development in order to both accurately assess resource potential and mitigate drilling costs by increasing drilling success rates. Employing a variety of surface and subsurface data sets, we present detailed 3D geologic analyses of two Great Basin geothermal systems, the actively producing Brady’s geothermal system and a ‘greenfield’ geothermal prospect at Astor Pass, Nevada. 3D modeling provides the framework for quantitative structural analyses. We combine 3D slip and dilation tendency analysis along fault zones and calculations of fault intersection density in the two geothermal systems with the locations of lithologies capable of supporting dense, interconnected fracture networks. The collocation of these permeability promoting characteristics with elevated heat represent geothermal ‘fairways’, areas with ideal conditions for geothermal fluid flow. Location of geothermal fairways at high resolution in 3D space can help to mitigate the costs of geothermal exploration by providing discrete drilling targets and data-based evaluations of reservoir potential.

  14. Eocene lignites from Cambay basin, Western India: An excellent source of hydrocarbon

    Directory of Open Access Journals (Sweden)

    P.K. Singh

    2016-09-01

    Full Text Available In the present paper lignites from the Cambay basin have been studied for their hydrocarbon potential. The samples were collected from three lignite fields–Vastan, Rajpardi and Tadkeshwar, and were investigated by petrography, chemical analyses and Rock-Eval pyrolysis. The results are well comparable with the empirically derived values. The study reveals that these ‘low rank C’ lignites are exceedingly rich in reactive macerals (huminite + liptinite while inertinite occurs in low concentration. These high volatile lignites generally have low ash yield except in few sections. The Rock-Eval data indicates the dominance of kerogen type-III with a little bit of type-II. The study reveals that the lignites of Vastan (lower and upper seams and Tadkeshwar upper seam are more gas-prone while Rajpardi and Tadkeshwar lower seams are oil-prone. Further, the fixed hydrocarbons are several times higher than the free hydrocarbons. The relation between TOC and fixed hydrocarbon indicates that these lignites are excellent source rock for hydrocarbon which could be obtained mainly through thermal cracking. The empirically derived values reveal a high conversion (94–96% and high oil yield (64–66% for these lignites.

  15. Subsurface recharge to the Tesuque aquifer system from selected drainage basins along the western side of the Sangre de Cristo Mountains near Santa Fe, New Mexico

    Science.gov (United States)

    Wasiolek, Maryann

    1995-01-01

    Water budgets developed for basins of five streams draining the western side of the Sangre de Cristo Mountains in northern New Mexico indicate that subsurface inflow along the mountain front is recharging the Tesuque aquifer system of the Espanola Basin. Approximately 14,700 acre-feet of water per year, or 12.7 percent of average annual precipitation over the mountains, is calculated to leave the mountain block and enter the basin as subsurface recharge from the drainage basins of the Rio Nambe, Rio en Medio, Tesuque Creek, Little Tesuque Creek, and Santa Fe River. About 5,520 acre- feet per year, or about 12 percent of average annual precipitation, is calculated to enter from the Rio Nambe drainage basin; about 1,710 acre- feet per year, or about 15 percent of average annual precipitation, is calculated to enter from the Rio en Medio drainage basin; about 1,530 acre- feet, or about 10 percent of average annual precipi- tation, is calculated to enter from the Tesuque Creek drainage basin; about 1,790 acre-feet, or about 19 percent of average annual precipitation, is calculated to enter from the Little Tesuque Creek drainage basin; and about 4,170 acre-feet per year, or about 12 percent average annual precipitation, is calculated to enter from the Santa Fe River drainage basin. Calculated subsurface recharge values were used to define maximum fluxes permitted along the specified-flux boundary defining the mountain front of the Sangre De Cristo Mountains in a numerical computer model of the Tesuque aquifer system near Santa Fe, New Mexico.

  16. Characteristics of Dengying Fm sedimentary sequence in the central–western Sichuan Basin and their controlling effect on gas accumulation

    Directory of Open Access Journals (Sweden)

    Long Wen

    2016-11-01

    Full Text Available A large gas reservoir in the Sinian Dengying Fm was recently discovered in Anyue area, central Sichuan Basin. In order to promote the oil and gas exploration in this area, it is of great significance to sustainably deepen the analysis on its high-quality reservoir distribution and source-reservoir assemblage. In this paper, a series of studies were performed on the sequence frameworks and sedimentary filling evolution characteristics of the Dengying Fm in central–western Sichuan Basin, and their controlling effects on the reservoir development and distribution and source-reservoir assemblage during its sedimentation. It is shown that the Deyang–Anyue paleo-rift is, on the whole, distributed in a NW direction, and is morphologically wide and steep in the north, but narrow and gentle in the south. There are two rift boundaries of the second and fourth members of Dengying Fm (Deng 2 Member and Deng 4 Member, respectively. The rift of Deng 2 Member is distributed in the shape of “U” in Deyang–Neijiang area. Dengying Fm is divided into four third-order sequences (SQ1–SQ4. In SQ3 of Gaoshiti–Moxi area, central Sichuan Basin, a complete sedimentation reflection structure of transgressive overlap and regressive progradation can be identified with early–middle Deng 4 Member platform margin. The paleo-rift was in embryo before the sedimentation of Sinian, so the sedimentary filling and lithofacies distribution of the Sinian were influenced by the inherited activities of pre-Sinian rifts. The favorable distribution zones of high-quality reservoirs are located at the rift margins of Deng 2 and Deng 4 Members that were formed respectively during the SQ2 and SQ4 and the platform margin of early Deng 4 Member that was formed during the SQ3. A laterally connected source-reservoir assemblage occurs at the margins of Deng 2 and Deng 4 Members around the Lower Cambrian source rocks of the paleo-rift. The northwestward extending margin zone along

  17. Controls on Erosion in the Western Tarim Basin: Implications for the Uplift of Northwest Tibet and Pamirs

    Science.gov (United States)

    Clift, P. D.; Zheng, H.; Carter, A.; Böning, P.; Jonell, T. N.; Pahnke, K.

    2016-12-01

    While the processes controlling erosion on the southern monsoon-influenced side of the Tibetan Plateau have been explored, those that dominate the drier regions north of the plateau are less well understood. We use a multiproxy approach to quantify erosion and assess variability in three rivers, the Hotan River draining the North Kunlun Block, the Yarkand River originating from the Karakoram, and the Kashgar River that flows from the eastern Pamirs. U-Pb zircon dating of modern river sands points to a strong control by topography and precipitation mediated through glaciation on erosion intensity in the Yarkand. Apatite fission track ages are younger in the Hotan River than in the Kashgar. Both rivers yield younger ages and faster exhumation rates than in the Transhimalaya and the western edge of the Tibetan Plateau. Exhumation rates are estimated at 1000 m/m.y in the North Kunlun and 500 m/m.y. in the eastern Pamirs, which are exhuming more slowly than the western Pamirs in the recent past. Our data indicate the Yarkand drainage system is relatively young as no sediment similar to the modern Yarkand River is found in older Cenozoic foreland sedimentary rocks. Uplift of the North Kunlun is interpreted to have started by 17 Ma, somewhat after uplift of the Pamirs and Songpan Garze in NW Tibet, which started before 24 Ma. Sediment eroded from the Kunlun reached the foreland basin between 14 and 11 Ma. Uplift appears to be propagating north through time with North Kunlun exhumation accelerating before 3.7 Ma, likely linked to enhanced rock uplift at that time.

  18. Mini-RF's Perspective of the Lunar Western Hemisphere and Orientale Basin's Ejecta Deposits

    Science.gov (United States)

    Cahill, J.; Patterson, G. W.; Raney, R. K.; Bussey, B.; Turtle, E. P.; Mini-RF Science Team

    2011-12-01

    The usefulness of radar is its sensitivity to surface roughness, subsurface scatterers, and composition. This attribute has provided a way to examine the nearside lunar surface and subsurface physical properties for several decades (Thompson et al. 1970). However, during this time radar was used relatively infrequently compared to other orbital instruments and techniques (e.g., near-infrared, neutron, and gamma-ray spectroscopy) to study the lunar surface. This was partly due to Earth-based surveys yielding data with lower spatial resolution, a limited variety of products, and coverage limited to the nearside of the Moon. That said, Earth-based radar products have continually improved in quality and studies derived from these data yielded a steady stream of additional information regarding the distribution of surface and subsurface geologic deposits, rock abundance, and accessing the possibility of water-ice on the lunar surface (e.g., Campbell et al. (2002), Campbell et al. (2005), Ghent et al. (2008), etc). These topics are uniquely in line with intended objectives of NASA's Lunar Reconnaissance Orbiter (LRO), which are to gather as much relevant information for the lunar physical environment as possible to enable future human exploration. Studies of the lunar western hemisphere's physical properties is a prime example of very relevant science being limited by the available spatial coverage of the area. Ghent et al. (2008)'s examination of the influence of Orientale ejecta on the southern highlands megaregolith was instrumental for not only identifying the extent and distribution of Orientale ejecta on the nearside of the Moon, but also for more fully characterizing its physical properties. Here, we present a spatially more comprehensive perspective of Orientale using radar data recently acquired by NASA's Lunar Reconnaissance Orbiter (LRO) Miniature Radio Frequency (Mini-RF) payload. Using Mini-RF we build upon previous work derived from Earth-based radar

  19. Mercury and flooding cycles in the Tapajós River basin, Brazilian Amazon: the role of periphyton of a floating macrophyte (Paspalum repens).

    Science.gov (United States)

    Coelho-Souza, Sérgio A; Guimarães, Jean R D; Miranda, Márcio R; Poirier, Hugo; Mauro, Jane B N; Lucotte, Marc; Mergler, Donna

    2011-06-15

    Methylmercury (MeHg) increases mercury (Hg) toxicity and is biomagnified in the trophic chain contaminating riverine Amazon populations. Freshwater macrophyte roots are a main site of Hg methylation in different Brazilian environments. Paspalum repens periphyton was sampled in four floodplain lakes during the dry, rainy and wet seasons for measurement of total Hg (THg), MeHg, Hg methylation potentials, %C, %N, δ(13)C, δ(15)N and bacterial heterotrophic production as (3)H-leucine incorporation rate. THg concentration varied from 67 to 198 ng/g and the potential of Me(203)Hg formation was expressive (1-23%) showing that periphyton is an important matrix both in the accumulation of Hg and in MeHg production. The concentration of MeHg varied from 1 to 6 ng/g DW and was positively correlated with Me(203)Hg formation. Though methylmercury formation is mainly a bacterial process, no significant correlation was observed between the methylation potentials and bacterial production. The multiple regressions analyses suggested a negative correlation between THg and %C and %N and between methylation potential and δ(13)C. The discriminant analysis showed a significant difference in periphyton δ(15)N, δ(13)C and THg between seasons, where the rainy season presented higher δ(15)N and the wet period lighter δ(13)C, lower THg values and higher Me(203)Hg formation. This exploratory study indicates that the flooding cycle could influence the periphyton composition, mercury accumulation and methylmercury production. Copyright © 2011. Published by Elsevier B.V.

  20. Further evidence for CCN aerosol concentrations determining the height of warm rain and ice initiation in convective clouds over the Amazon basin

    Directory of Open Access Journals (Sweden)

    R. C. Braga

    2017-12-01

    Full Text Available We have investigated how aerosols affect the height above cloud base of rain and ice hydrometeor initiation and the subsequent vertical evolution of cloud droplet size and number concentrations in growing convective cumulus. For this purpose we used in situ data of hydrometeor size distributions measured with instruments mounted on HALO aircraft during the ACRIDICON–CHUVA campaign over the Amazon during September 2014. The results show that the height of rain initiation by collision and coalescence processes (Dr, in units of meters above cloud base is linearly correlated with the number concentration of droplets (Nd in cm−3 nucleated at cloud base (Dr ≈ 5 ⋅ Nd. Additional cloud processes associated with Dr, such as GCCN, cloud, and mixing with ambient air and other processes, produce deviations of  ∼  21 % in the linear relationship, but it does not mask the clear relationship between Dr and Nd, which was also found at different regions around the globe (e.g., Israel and India. When Nd exceeded values of about 1000 cm−3, Dr became greater than 5000 m, and the first observed precipitation particles were ice hydrometeors. Therefore, no liquid water raindrops were observed within growing convective cumulus during polluted conditions. Furthermore, the formation of ice particles also took place at higher altitudes in the clouds in polluted conditions because the resulting smaller cloud droplets froze at colder temperatures compared to the larger drops in the unpolluted cases. The measured vertical profiles of droplet effective radius (re were close to those estimated by assuming adiabatic conditions (rea, supporting the hypothesis that the entrainment and mixing of air into convective clouds is nearly inhomogeneous. Additional CCN activation on aerosol particles from biomass burning and air pollution reduced re below rea, which further inhibited the formation of raindrops and ice particles and resulted in even higher

  1. Further evidence for CCN aerosol concentrations determining the height of warm rain and ice initiation in convective clouds over the Amazon basin

    Science.gov (United States)

    Campos Braga, Ramon; Rosenfeld, Daniel; Weigel, Ralf; Jurkat, Tina; Andreae, Meinrat O.; Wendisch, Manfred; Pöschl, Ulrich; Voigt, Christiane; Mahnke, Christoph; Borrmann, Stephan; Albrecht, Rachel I.; Molleker, Sergej; Vila, Daniel A.; Machado, Luiz A. T.; Grulich, Lucas

    2017-12-01

    We have investigated how aerosols affect the height above cloud base of rain and ice hydrometeor initiation and the subsequent vertical evolution of cloud droplet size and number concentrations in growing convective cumulus. For this purpose we used in situ data of hydrometeor size distributions measured with instruments mounted on HALO aircraft during the ACRIDICON-CHUVA campaign over the Amazon during September 2014. The results show that the height of rain initiation by collision and coalescence processes (Dr, in units of meters above cloud base) is linearly correlated with the number concentration of droplets (Nd in cm-3) nucleated at cloud base (Dr ≈ 5 ṡ Nd). Additional cloud processes associated with Dr, such as GCCN, cloud, and mixing with ambient air and other processes, produce deviations of ˜ 21 % in the linear relationship, but it does not mask the clear relationship between Dr and Nd, which was also found at different regions around the globe (e.g., Israel and India). When Nd exceeded values of about 1000 cm-3, Dr became greater than 5000 m, and the first observed precipitation particles were ice hydrometeors. Therefore, no liquid water raindrops were observed within growing convective cumulus during polluted conditions. Furthermore, the formation of ice particles also took place at higher altitudes in the clouds in polluted conditions because the resulting smaller cloud droplets froze at colder temperatures compared to the larger drops in the unpolluted cases. The measured vertical profiles of droplet effective radius (re) were close to those estimated by assuming adiabatic conditions (rea), supporting the hypothesis that the entrainment and mixing of air into convective clouds is nearly inhomogeneous. Additional CCN activation on aerosol particles from biomass burning and air pollution reduced re below rea, which further inhibited the formation of raindrops and ice particles and resulted in even higher altitudes for rain and ice initiation.

  2. Research into Mercury Exposure and Health Education in Subsistence Fish-Eating Communities of the Amazon Basin: Potential Effects on Public Health Policy

    Directory of Open Access Journals (Sweden)

    José G. Dórea

    2010-09-01

    Full Text Available The neurotoxic effects of fish-methylmercury (meHg consumed regularly are considered hazardous to fetuses and newborn infants; as a result fish consumption advisories are an important asset to control meHg exposure in affluent societies. These concerns are now part of health promotion programs for Amazon subsistence villagers. While urban dwellers in affluent societies can choose an alternative nutritious diet, traditional and subsistence communities are caught up in controversial issues and lifestyle changes with unintended health consequences. Traditional fish-eating populations of industrialized and non-industrialized regions may be exposed to different neurotoxic substances: man-made pollutants and environmentally occurring meHg. Additionally, in non-industrialized countries, pregnant women and infants are still being immunized with thimerosal-containing vaccines (TCVs which degrade to ethylmercury (etHg. Therefore, the complexity involving fish-meHg associated with wild-fish choices and Hg exposure derived from TCVs is difficult to disentangle and evaluate: are villagers able to distinguish exposure to differently hazardous chemical forms of Hg (inorganic, fish-meHg, and injected etHg? Is it possible that instead of helping to prevent a plausible (unperceived fish-meHg associated neurocognitive delay we may inadvertently arouse panic surrounding Hg exposure and disrupt subsistence fish-eating habits (necessary for survival and life-saving vaccination programs (required by public health authorities? These questions characterize the incompleteness of information related on the various chemical forms of Hg exposure and the need to convey messages that do not disrupt nutritional balance and disease prevention policies directed at Amazonian subsistence communities.

  3. Study on driving forces of wetland change in the Western Liaohe River basin based on random forest model

    Science.gov (United States)

    Wu, Menghong; Yang, Changbao; Zhang, Yanhong; Lin, Nan

    2017-05-01

    Based on the platform of RS and GIS, random forest progression model is used for study driving force of wetland change in western Liaohe river basin, five influencing factors which include elevation, slope, temperature, precipitation and population density are chosen to establish random forest progression model about the wetland change and the driving factors. Using the the mean value of the prediction accuracy outside the bag calculated by the model to evaluate the importance of the variables. The result indicates that the coefficient of partial correlation between precipitation and wetland density is the largest among the five influencing factors, followed by temperature, population density, elevation and slope is smallest. The influence of natural factors on the change of wetland density is mainly reflected in precipitation and temperature factors, and the precipitation is obviously higher than that of temperature, under the influence of human factors, the influence of population density factor on wetland density is higher than that of elevation and slope factor. The result shows that in the past 40 years, the human activities in the study area have increased the density of wetland to some extent, but it is not the main factor.

  4. Ichnofabrics of the Capdevila Formation (early Eocene) in the Los Palacios Basin (western Cuba): Paleoenvironmental and paleoecological implications

    Science.gov (United States)

    Villegas-Martín, Jorge; Netto, Renata Guimarães; Lavina, Ernesto Luis Correa; Rojas-Consuegra, Reinaldo

    2014-12-01

    The ichnofabrics present in the early Eocene siliciclastic deposits of the Capdevila Formation exposed in the Pinar del Rio area (Los Palacios Basin, western Cuba) are analyzed in this paper and their paleoecological and paleoenvironmental significance are discussed. Nine ichnofabrics were recognized in the dominantly sandy sedimentary succession: Ophiomorpha, Asterosoma, Thalassinoides, Palaeophycus, Scolicia, Bichordites-Thalassinoides, Rhizocorallium, Scolicia-Thalassinoides and rhizobioturbation. Diversity of ichnofauna is low and burrows made by detritus-feeding organisms in well oxygenated and stenohaline waters predominate. Suites of the Cruziana and Skolithos Ichnofacies lacking their archetypical characteristics were recognized, being impoverished in diversity and presenting dominance of echinoderm and decapods crustacean burrows as a response to the environmental stress caused by the high frequency of deposition. The ichnofabric distribution in the studied succession, its recurrence in the sandstone beds and the presence of a Glossifungites Ichnofacies suite with rhizobioturbation associated reflect a shoaling-upward event with subaerial exposure of the substrate. The integrated analysis of the ichnology and the sedimentary facies suggests deposition in a shallow slope frequently impacted by gravitational flows and high-energy events. The evidence of substrate exposure indicates the occurrence of a forced regression and suggests the existence of a sequence boundary at the top of the Capdevila Formation.

  5. Strategy to design the sea-level monitoring networks for small tsunamigenic oceanic basins: the Western Mediterranean case

    Directory of Open Access Journals (Sweden)

    F. Schindelé

    2008-09-01

    Full Text Available The 26 December 2004 Indian Ocean tsunami triggered a number of international and national initiatives aimed at establishing modern, reliable and robust tsunami warning systems. In addition to the seismic network for initial warning, the main component of the monitoring system is the sea level network. Networks of coastal tide gages and tsunameters are implemented to detect the tsunami after the occurrence of a large earthquake, to confirm or refute the tsunami occurrence. Large oceans tsunami monitoring currently in place in the Pacific and in implementation in the Indian Ocean will be able to detect tsunamis in 1 h. But due to the very short time of waves propagation, in general less than 1 h, a tsunami monitoring system in a smaller basin requires a denser network located close to the seismic zones. A methodology is proposed based on the modeling of tsunami travel time and waveform, and on the estimation of the delay of transmission to design the location and the spacing of the stations. In the case of Western Mediterranean, we demonstrate that a network of around 17 coastal tide gages and 13 tsunameters located at 50 km along the shore is required to detect and measure nearly all tsunamis generated on the Northern coasts of Africa.

  6. Inversions for earthquake focal mechanisms and regional stress in the Kachchh Rift Basin, western India: Tectonic implications

    Science.gov (United States)

    Singh, A. P.; Zhao, L.; Kumar, Santsoh; Mishra, Smita

    2016-03-01

    More than a decade after the 2001 MW 7.7 Bhuj earthquake in western India, aftershocks up to MW 5.0 are still continuing around the rupture zone in the Kachchh Rift Basin. Over the years, some surrounding faults in the region have been activated, and a transverse fault generated an MW 5.1 earthquake in 2012. Most of the earthquakes occur in the lower crust at depths between 15 and 35 km. We have determined focal mechanism solutions of 47 earthquakes (MW 3.2-5.1) that were recorded by a 60-station broadband network during 2007-2014 within an area of 50 km radius of the 2001 main shock. South dipping nodal planes in most of the solutions correlate well with the active faults. The earthquakes near the epicenter of the 2001 main shock primarily show reverse-faulting mechanisms. The surrounding earthquakes in the area, however, show predominantly strike-slip mechanisms. The P axes of the earthquakes mostly oriented in north-south, and the T axes in east-west. However, the orientations of the P and T axes exhibit more complexity near the source area of the main shock. Stress field inversion of the solutions yields a dominant north-south compression, which is consistent with the ambient tectonic stress field owing to the northward movement of the Indian Plate with respect to the Eurasian Plate. The geodetic measurements are in reasonable agreement with our results.

  7. Gone with the plate: the opening of the Western Mediterranean basin drove the diversification of ground-dweller spiders

    Directory of Open Access Journals (Sweden)

    Bidegaray-Batista Leticia

    2011-10-01

    Full Text Available Abstract Background The major islands of the Western Mediterranean--Corsica, Sardinia, and the Balearic Islands--are continental terrenes that drifted towards their present day location following a retreat from their original position on the eastern Iberian Peninsula about 30 million years ago. Several studies have taken advantage of this well-dated geological scenario to calibrate molecular rates in species for which distributions seemed to match this tectonic event. Nevertheless, the use of external calibration points has revealed that most of the present-day fauna on these islands post-dated the opening of the western Mediterranean basin. In this study, we use sequence information of the cox1, nad1, 16S, L1, and 12S mitochondrial genes and the 18S, 28S, and h3 nuclear genes, along with relaxed clock models and a combination of biogeographic and fossil external calibration points, to test alternative historical scenarios of the evolutionary history of the ground-dweller spider genus Parachtes (Dysderidae, which is endemic to the region. Results We analyse 49 specimens representing populations of most Parachtes species and close relatives. Our results reveal that both the sequence of species formation in Parachtes and the estimated divergence times match the geochronological sequence of separation of the main islands, suggesting that the diversification of the group was driven by Tertiary plate tectonics. In addition, the confirmation that Parachtes diversification matches well-dated geological events provides a model framework to infer substitution rates of molecular markers. Divergence rates estimates ranged from 3.5% My-1 (nad1 to 0.12% My-1 (28S, and the average divergence rate for the mitochondrial genes was 2.25% My-1, very close to the "standard" arthropod mitochondrial rate (2.3% My-1. Conclusions Our study provides the first unequivocal evidence of terrestrial endemic fauna of the major western Mediterranean islands, whose origin can

  8. Historical biogeography of the land snail Cornu aspersum: a new scenario inferred from haplotype distribution in the Western Mediterranean basin

    Directory of Open Access Journals (Sweden)

    Madec Luc

    2010-01-01

    Full Text Available Abstract Background Despite its key location between the rest of the continent and Europe, research on the phylogeography of north African species remains very limited compared to European and North American taxa. The Mediterranean land mollusc Cornu aspersum (= Helix aspersa is part of the few species widely sampled in north Africa for biogeographical analysis. It then provides an excellent biological model to understand phylogeographical patterns across the Mediterranean basin, and to evaluate hypotheses of population differentiation. We investigated here the phylogeography of this land snail to reassess the evolutionary scenario we previously considered for explaining its scattered distribution in the western Mediterranean, and to help to resolve the question of the direction of its range expansion (from north Africa to Europe or vice versa. By analysing simultaneously individuals from 73 sites sampled in its putative native range, the present work provides the first broad-scale screening of mitochondrial variation (cyt b and 16S rRNA genes of C. aspersum. Results Phylogeographical structure mirrored previous patterns inferred from anatomy and nuclear data, since all haplotypes could be ascribed to a B (West or a C (East lineage. Alternative migration models tested confirmed that C. aspersum most likely spread from north Africa to Europe. In addition to Kabylia in Algeria, which would have been successively a centre of dispersal and a zone of secondary contacts, we identified an area in Galicia where genetically distinct west and east type populations would have regained contact. Conclusions Vicariant and dispersal processes are reviewed and discussed in the light of signatures left in the geographical distribution of the genetic variation. In referring to Mediterranean taxa which show similar phylogeographical patterns, we proposed a parsimonious scenario to account for the "east-west" genetic splitting and the northward expansion of the

  9. Nature of the crust in the Laxmi Basin (14°-20°N), western continental margin of India

    Digital Repository Service at National Institute of Oceanography (India)

    Krishna, K.S.; Rao, D.G.; Sar, D.

    anomaly of Laxmi Ridge. Intrusive structures mapped in the Laxmi Basin coincide with significant magnetic anomalies, which were earlier interpreted as seafloor-spreading anomalies. Model studies reveal that the Laxmi Basin consists of ~14 km thick...

  10. COMPOSITION AND OCCURRENCE OF THE GRANDISPORA MACULOSA ZONAL ASSEMBLAGE (MISSISSIPPIAN IN THE SUBSURFACE OF THE CARNARVON BASIN AND THE COOLCALALAYA SUB-BASIN OF WESTERN AUSTRALIA, AND ITS GONDWANAN DISTRIBUTION

    Directory of Open Access Journals (Sweden)

    GEOFFREY PLAYFORD

    2017-04-01

    Full Text Available The Grandispora maculosa miospore assemblage – initially described in 1968 from Middle-Late Mississippian strata of New South Wales (eastern Australia – is well represented in samples examined herein from 10 Western Australian subsurface sections located in the northern Perth Basin (Coolcalalaya Sub-basin and, to its immediate north, in several sub-basins of the southern and northern sectors of the Carnarvon Basin. Of particular stratigraphic-correlative importance is the presence of the eponymous G. maculosa together with, inter alia, Reticulatisporites magnidictyus, Verrucosisporites quasigobbettii, V. gregatus, Apiculiretusispora tersa, Raistrickia accinta, R. radiosa, Foveosporites pellucidus, and Cordylosporites asperidictyus. Four species are newly described herein: Apiculatasporites spiculatus, Dibolisporites sejunctus, Raistrickia corymbiata, and Vallatisporites valentulus. Published accounts from elsewhere in Gondwana collectively signify the widespread dissemination of the G. maculosa palynoflora, particularly through northern and western regions of the supercontinent, thus affording an effective means of intra-Gondwanan stratal correlation. Limited absolute dating and stratigraphic-successional considerations across Gondwana indicate that the age of the G. maculosa Assemblage can be bracketed within the middle Visean-early Serpukhovian of the Middle-Late Mississippian. This age is supported by the complete absence of bilaterally symmetrical, non-striate, saccate pollen grains, produced by walchian conifers, which were introduced globally (including in Australia and near-synchronously late in the Serpukhovian. Cryptogamic land plants (ferns, articulates, lycophytes are the inferred source of the palynoflora.

  11. Statistical processing the results of interlaboratory testing the grain-size distribution of sand and gravel from the western part of the Kostolac basin

    OpenAIRE

    Urošević, Daniela; Vukićević, Mirjana; Davidović, Nebojša

    2012-01-01

    This paper presents the results of interlaboratory testing the grain-size distribution of sand and gravel on representative samples from the site of the western part of the Kostolac Basin. The results were statistically processed by two ways: Numerical method: the Cochran test of accuracy and Graphic interpretation: the MANDEL technique of consistency in accordance with the Standard SRPS ISO 5725-2 [1,2]. The followings were calculated: repeatability variance Sr2; interlaboratory variance SL ...

  12. Assimilation of lidar signals: application to aerosol forecasting in the western Mediterranean basin

    Science.gov (United States)

    Wang, Y.; Sartelet, K. N.; Bocquet, M.; Chazette, P.; Sicard, M.; D'Amico, G.; Léon, J. F.; Alados-Arboledas, L.; Amodeo, A.; Augustin, P.; Bach, J.; Belegante, L.; Binietoglou, I.; Bush, X.; Comerón, A.; Delbarre, H.; García-Vízcaino, D.; Guerrero-Rascado, J. L.; Hervo, M.; Iarlori, M.; Kokkalis, P.; Lange, D.; Molero, F.; Montoux, N.; Muñoz, A.; Muñoz, C.; Nicolae, D.; Papayannis, A.; Pappalardo, G.; Preissler, J.; Rocadenbosch, F.; Sellegri, K.; Wagner, F.; Dulac, F.

    2014-11-01

    This paper presents a new application of assimilating lidar signals to aerosol forecasting. It aims at investigating the impact of a ground-based lidar network on the analysis and short-term forecasts of aerosols through a case study in the Mediterranean basin. To do so, we employ a data assimilation (DA) algorithm based on the optimal interpolation method developed in the Polair3D chemistry transport model (CTM) of the Polyphemus air quality modelling platform. We assimilate hourly averaged normalised range-corrected lidar signals (PR2) retrieved from a 72 h period of intensive and continuous measurements performed in July 2012 by ground-based lidar systems of the European Aerosol Research Lidar Network (EARLINET) integrated into the Aerosols, Clouds, and Trace gases Research InfraStructure (ACTRIS) network and an additional system in Corsica deployed in the framework of the pre-ChArMEx (Chemistry-Aerosol Mediterranean Experiment)/TRAQA (TRAnsport à longue distance et Qualité de l'Air) campaign. This lidar campaign was dedicated to demonstrating the potential operationality of a research network like EARLINET and the potential usefulness of assimilation of lidar signals to aerosol forecasts. Particles with an aerodynamic diameter lower than 2.5 μm (PM2.5) and those with an aerodynamic diameter higher than 2.5 μm but lower than 10 μm (PM10-2.5) are analysed separately using the lidar observations at each DA step. First, we study the spatial and temporal influences of the assimilation of lidar signals on aerosol forecasting. We conduct sensitivity studies on algorithmic parameters, e.g. the horizontal correlation length (Lh) used in the background error covariance matrix (50 km, 100 km or 200 km), the altitudes at which DA is performed (0.75-3.5 km, 1.0-3.5 km or 1.5-3.5 km a.g.l.) and the assimilation period length (12 h or 24 h). We find that DA with Lh = 100 km and assimilation from 1.0 to 3.5 km a.g.l. during a 12 h assimilation period length leads to the

  13. Mercury and flooding cycles in the Tapajos river basin, Brazilian Amazon: The role of periphyton of a floating macrophyte (Paspalum repens)

    Energy Technology Data Exchange (ETDEWEB)

    Coelho-Souza, Sergio A., E-mail: sacs@biof.ufrj.br [Lab. Tracadores Wolfgang C. Pfeiffer, SL 049, Instituto de Biofisica Carlos Chagas Filho/UFRJ, Bloco G, Centro de Ciencias e Saude, Ilha do Fundao, Rio de Janeiro, RJ, CEP 21949-902 (Brazil); Guimaraes, Jean R.D.; Miranda, Marcio R. [Lab. Tracadores Wolfgang C. Pfeiffer, SL 049, Instituto de Biofisica Carlos Chagas Filho/UFRJ, Bloco G, Centro de Ciencias e Saude, Ilha do Fundao, Rio de Janeiro, RJ, CEP 21949-902 (Brazil); Poirier, Hugo [Chaire de Reserche en Environment, Universite du Quebec a Montreal (UQaM), CP 8888, Montreal, H3C 3P8 (Canada); Mauro, Jane B.N. [Lab. Tracadores Wolfgang C. Pfeiffer, SL 049, Instituto de Biofisica Carlos Chagas Filho/UFRJ, Bloco G, Centro de Ciencias e Saude, Ilha do Fundao, Rio de Janeiro, RJ, CEP 21949-902 (Brazil); Lucotte, Marc [Chaire de Reserche en Environment, Universite du Quebec a Montreal (UQaM), CP 8888, Montreal, H3C 3P8 (Canada); Mergler, Donna [CINBIOSE, UQaM, CP 8888, succ. Centre-ville, Montreal, H3C 3P8 (Canada)

    2011-06-15

    Methylmercury (MeHg) increases mercury (Hg) toxicity and is biomagnified in the trophic chain contaminating riverine Amazon populations. Freshwater macrophyte roots are a main site of Hg methylation in different Brazilian environments. Paspalum repens periphyton was sampled in four floodplain lakes during the dry, rainy and wet seasons for measurement of total Hg (THg), MeHg, Hg methylation potentials, %C, %N, {delta}{sup 13}C, {delta}{sup 15}N and bacterial heterotrophic production as {sup 3}H-leucine incorporation rate. THg concentration varied from 67 to 198 ng/g and the potential of Me{sup 203}Hg formation was expressive (1-23%) showing that periphyton is an important matrix both in the accumulation of Hg and in MeHg production. The concentration of MeHg varied from 1 to 6 ng/g DW and was positively correlated with Me{sup 203}Hg formation. Though methylmercury formation is mainly a bacterial process, no significant correlation was observed between the methylation potentials and bacterial production. The multiple regressions analyses suggested a negative correlation between THg and %C and %N and between methylation potential and {delta}{sup 13}C. The discriminant analysis showed a significant difference in periphyton {delta}{sup 15}N, {delta}{sup 13}C and THg between seasons, where the rainy season presented higher {delta}{sup 15}N and the wet period lighter {delta}{sup 13}C, lower THg values and higher Me{sup 203}Hg formation. This exploratory study indicates that the flooding cycle could influence the periphyton composition, mercury accumulation and methylmercury production. - Research highlights: {yields} During rainy season mercury (Hg{sup 2+}) is carried out from terrestrial to aquatic systems by runoff. {yields} Macrophyte roots accumulates Hg{sup 2+} from suspended particulate matter (SPM). {yields} Hg methylation increases during the wet season. {yields} Flooded forest is a source of labile organic carbon and bioavailable Hg. {yields} Macrophytes

  14. LBA-ECO LC-24 Historical Roads of the Legal Amazon: 1968-1993

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set contains ESRI shapefiles of historical roads (basin-wide federal and state roads) in nine Brazilian states for the Legal Amazon: Amazonas,...

  15. LBA-ECO LC-24 Historical Roads of the Legal Amazon: 1968-1993

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains ESRI shapefiles of historical roads (basin-wide federal and state roads) in nine Brazilian states for the Legal Amazon: Amazonas, Para, Acre,...

  16. Temperature, Salinity, Oxygen, Phosphate, Silicate, Nitrite, pH and Alkalinity data collected in the Black Sea, Tyrrhenian Sea and Western Basin from R/Vs GORIZONT and OKEANOGRAF, 1960 - 1969 (NODC Accession 0074609)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, Salinity, Oxygen, Phosphate, Silicate, Nitrite, pH and Alkalinity data collected in the Black Sea, Tyrrhenian Sea and Western Basin of the Mediterranean...

  17. Overview of groundwater quality in the Piceance Basin, western Colorado, 1946--2009

    Science.gov (United States)

    Thomas, J.C.; McMahon, P.B.

    2013-01-01

    Groundwater-quality data from public and private sources for the period 1946 to 2009 were compiled and put into a common data repository for the Piceance Basin. The data repository is available on the web at http://rmgsc.cr.usgs.gov/cwqdr/Piceance/index.shtml. A subset of groundwater-quality data from the repository was compiled, reviewed, and checked for quality assurance for this report. The resulting dataset consists of the most recently collected sample from 1,545 wells, 1,007 (65 percent) of which were domestic wells. From those samples, the following constituents were selected for presentation in this report: dissolved oxygen, dissolved solids, pH, major ions (chloride, sulfate, fluoride), trace elements (arsenic, barium, iron, manganese, selenium), nitrate, benzene, toluene, ethylbenzene, xylene, methane, and the stable isotopic compositions of water and methane. Some portion of recharge to most of the wells for which data were available was derived from precipitation (most likely snowmelt), as indicated by δ2H [H2O] and δ18O[H2O] values that plot along the Global Meteoric Water Line and near the values for snow samples collected in the study area. Ninety-three percent of the samples were oxic, on the basis of concentrations of dissolved oxygen that were greater than or equal to 0.5 milligrams per liter. Concentration data were compared with primary and secondary drinking-water standards established by the U.S. Environmental Protection Agency. Constituents that exceeded the primary standards were arsenic (13 percent), selenium (9.2 percent), fluoride (8.4 percent), barium (4.1 percent), nitrate (1.6 percent), and benzene (0.6 percent). Concentrations of toluene, xylenes, and ethylbenzene did not exceed standards in any samples. Constituents that exceeded the secondary standard were dissolved solids (72 percent), sulfate (37 percent), manganese (21 percent), iron (16 percent), and chloride (10 percent). Drinking-water standards have not been established for

  18. Growth Normal Faulting at the Western Edge of the Metropolitan Taipei Basin since the Last Glacial Maximum, Northern Taiwan

    Directory of Open Access Journals (Sweden)

    Chih-Tung Chen

    2010-01-01

    Full Text Available Growth strata analysis is an useful tool in understanding kinematics and the evolution of active faults as well as the close relationship between sedimentation and tectonics. Here we present the Shanchiao Fault as a case study which is an active normal fault responsible for the formation of the 700-m-thick late Quaternary deposits in Taipei Basin at the northern tip of the Taiwan mountain belt. We compiled a sedimentary record, particularly the depositional facies and their dated ages, at three boreholes (SCF-1, SCF-2 and WK-1, from west to east along the Wuku Profile that traverses the Shanchiao Fault at its central segment. By incorporating the global sea level change curve, we find that thickness changes of sediments and changes of depositional environments in the Wuku area are in a good agreement with a rapid sea level rise since the Last Glacial Maximum (LGM of about 23 ka. Combining depositional facies changes and their ages with their thickness, we are able to introduce a simple back-stripping method to reconstruct the evolution of growing strata across the Shanchiao Fault since the LGM. We then estimate the vertical tectonic slip rate since 23 ka, which exhibits 2.2 mm yr-1 between SCF-2 and WK-1 and 1.1 mm yr-1 between SCF-1 and SCF-2. We also obtain the Holocene tectonic subsidence rate of 2.3 mm yr-1 at WK-1 and 0.9 mm yr-1 at SCF-2 since 8.4 ka. We thus conclude that the fault zone consists of a high-angle main fault to the east between SCF-2 and WK-1 and a western lower-angle branch fault between SCF-1 and SCF-2, resembling a tulip structure developed under sinistral transtensional tectonism. We find that a short period of 600-yr time span in 9 - 8.4 ka shows important tectonic subsidence of 7.4 and 3.3 m for the main and branch fault, respectively, consistent with possible earthquake events proposed by previous studies during that time. A correlation between geomorphology and subsurface geology in the Shanchiao Fault zone shows

  19. Tropical Peat and Peatland Development in the Floodplains of the Greater Pamba Basin, South-Western India during the Holocene.

    Science.gov (United States)

    Kumaran, Navnith K P; Padmalal, Damodaran; Limaye, Ruta B; S, Vishnu Mohan; Jennerjahn, Tim; Gamre, Pradeep G

    2016-01-01

    Holocene sequences in the humid tropical region of Kerala, South-western (SW) India have preserved abundance of organic-rich sediments in the form of peat and its rapid development in a narrow time frame towards Middle Holocene has been found to be significant. The sub-coastal areas and flood plains of the Greater Pamba Basin have provided palaeorecords of peat indicating that the deposits are essentially formed within freshwater. The combination of factors like stabilized sea level and its subsequent fall since the Middle Holocene, topographic relief and climatic conditions led to rapid peat accumulation across the coastal lowlands. The high rainfall and massive floods coupled with a rising sea level must have inundated > 75% of the coastal plain land converting it into a veritable lagoon-lake system that eventually led to abrupt termination of the forest ecosystem and also converted the floodplains into peatland where accumulation of peat almost to 2.0-3.0 m thickness in coastal lowlands and river basins during the shorter interval in the Middle Holocene. Vast areas of the coastal plains of Kerala have been converted into carbon rich peatland during the Middle Holocene and transforming the entire coastal stretch and associated landforms as one of the relatively youngest peatlands in the extreme southern tip of India. Unlike the uninterrupted formation of peatlands of considerable extent during the Holocene in Southeast Asia, the south Peninsular Indian region has restricted and short intervals of peatlands in the floodplains and coastal lowlands. Such a scenario is attributed to the topographic relief of the terrain and the prevailing hydrological regimes and environmental conditions as a consequence of monsoon variability since Middle Holocene in SW India. Considering the tropical coastal lowlands and associated peatlands are excellent repositories of carbon, they are very important for regional carbon cycling and habitat diversity. The alarming rate of land

  20. Late Devonian carbonate magnetostratigraphy from the Oscar and Horse Spring Ranges, Lennard Shelf, Canning Basin, Western Australia

    Science.gov (United States)

    Hansma, Jeroen; Tohver, Eric; Yan, Maodu; Trinajstic, Kate; Roelofs, Brett; Peek, Sarah; Slotznick, Sarah P.; Kirschvink, Joseph; Playton, Ted; Haines, Peter; Hocking, Roger

    2015-01-01

    The Late Devonian was a time of major evolutionary change encompassing the fifth largest mass extinction, the Frasnian-Famennian event. In order to establish a chronological framework for global correlation before, during, and following the Frasnian-Famennian mass extinction, we carried out a coupled magnetostratigraphic and biostratigraphic study of two stratigraphic sections in the Upper Devonian carbonate reef complexes of the Lennard Shelf, in the Canning Basin, Western Australia. Magnetostratigraphy from these rocks provides the first high-resolution definition of the Late Devonian magnetic polarity timescale. A 581-m-reference section and an 82-m overlapping section through the marginal slope facies (Napier Formation) of the Oscar Range as well as a 117-m section at Horse Spring (Virgin Hills Formation) were sampled at decimeter to meter scale for magnetostratigraphy. Conodont biostratigraphy was used to correlate both sections, and link magnetostratigraphic polarity zones to a globally established biostratigraphy. A stable, Characteristic Remanent Magnetization (ChRM) with dual polarities (NE, shallowly upward and SW, shallowly downward) is recovered from ∼ 60% of all samples, with magnetite inferred to be the chief magnetic carrier from thermal demagnetization characteristics. These directions define a geomagnetic pole at 49.5°S/285.8°E and α95 = 2.4 (n = 501), placing the Canning Basin at 9.9°S during the Late Devonian, consistent with carbonate reef development at this time. A conservative interpretation of the magnetostratigraphy shows the recovery of multiple reversals from both sections, not including possible cryptochrons and short duration magnetozones. Field tests for primary remanence include positive reversal tests and matching magnetozones from an overlapping section in the Oscar Range. A strong correlation was found between magnetic polarity stratigraphies of the Oscar Range and Horse Spring sections, and we correlate 12

  1. Development of regional future climate change scenarios in South America using the Eta CPTEC/HadCM3 climate change projections: climatology and regional analyses for the Amazon, Sao Francisco and the Parana River basins

    Energy Technology Data Exchange (ETDEWEB)

    Marengo, Jose A.; Chou, Sin Chan; Alves, Lincoln M.; Pesquero, Jose F.; Soares, Wagner R.; Santos, Daniel C.; Lyra, Andre A.; Sueiro, Gustavo; Chagas, Diego J.; Gomes, Jorge L.; Bustamante, Josiane F.; Tavares, Priscila [National Institute for Space Research (INPE) Cachoeira Paulista, Sao Paulo (Brazil); Kay, Gillian; Betts, Richard [UK Met Office Hadley Centre, Exeter, Devon (United Kingdom)

    2012-05-15

    The objective of this study is to assess the climate projections over South America using the Eta-CPTEC regional model driven by four members of an ensemble of the Met Office Hadley Centre Global Coupled climate model HadCM3. The global model ensemble was run over the twenty-first century according to the SRES A1B emissions scenario, but with each member having a different climate sensitivity. The four members selected to drive the Eta-CPTEC model span the sensitivity range in the global model ensemble. The Eta-CPTEC model nested in these lateral boundary conditions was configured with a 40-km grid size and was run over 1961-1990 to represent baseline climate, and 2011-2100 to simulate possible future changes. Results presented here focus on austral summer and winter climate of 2011-2040, 2041-2070 and 2071-2100 periods, for South America and for three major river basins in Brazil. Projections of changes in upper and low-level circulation and the mean sea level pressure (SLP) fields simulate a pattern of weakening of the tropical circulation and strengthening of the subtropical circulation, marked by intensification at the surface of the Chaco Low and the subtropical highs. Strong warming (4-6 C) of continental South America increases the temperature gradient between continental South America and the South Atlantic. This leads to stronger SLP gradients between continent and oceans, and to changes in moisture transport and rainfall. Large rainfall reductions are simulated in Amazonia and Northeast Brazil (reaching up to 40%), and rainfall increases around the northern coast of Peru and Ecuador and in southeastern South America, reaching up to 30% in northern Argentina. All changes are more intense after 2040. The Precipitation-Evaporation (P-E) difference in the A1B downscaled scenario suggest water deficits and river runoff reductions in the eastern Amazon and Sao Francisco Basin, making these regions susceptible to drier conditions and droughts in the future

  2. Suspended sediment dynamics in the Amazon River of Peru

    Science.gov (United States)

    Armijos, Elisa; Crave, Alain; Vauchel, Philippe; Fraizy, Pascal; Santini, William; Moquet, Jean-Sèbastien; Arevalo, Nore; Carranza, Jorge; Guyot, Jean-Loup

    2013-07-01

    The erosion and transport of sediments allow us to understand many activities of significance, such as crust evolution, climate change, uplift rates, continental processes, the biogeochemical cycling of pollutants and nutrients. The Amazon basin of Peru has contrasting physiographic and climatic characteristics between the Andean piedmont and the plains and between the north and south of the basin which is why there are 8 gauging stations located along the principal rivers of the Andean piedmont (Marañón, Huallaga, Ucayali) and the plain (Marañón, Tigre, Napo, Ucayali and Amazon rivers). Since 2003, the ORE-Hybam (IRD-SENAMHI-UNALM) observatory has performed out regular measurements at strategic points of the Amazon basin to understand and model the systems, behavior and long-term dynamics. On the Andean piedmont, the suspended yields are governed by a simple model with a relationship between the river discharge and the sediment concentration. In the plain, the dilution effect of the concentrations can create hysteresis in this relationship on a monthly basis. The Amazon basin of Peru has a sediment yield of 541 *106 t year-1, 70% comes from the southern basin.

  3. A glacier inventory for the western Nyainqentanglha Range and the Nam Co Basin, Tibet, and glacier changes 1976–2009

    Directory of Open Access Journals (Sweden)

    T. Bolch

    2010-09-01

    Full Text Available The western Nyainqentanglha Range is located in the south-eastern centre of the Tibetan Plateau. Its north-western slopes drain into Lake Nam Co. The region is of special interest for glacio-climatological research as it is influenced by both the continental climate of Central Asia and the Indian Monsoon system, and situated at the transition zone between temperate and subcontinental glaciers. A glacier inventory for the whole mountain range was generated for the year around 2001 using automated remote sensing and GIS techniques based on Landsat ETM+ and SRTM3 DEM data. Glacier change analysis was based on data from Hexagon KH-9 and Landsat MSS (both 1976, Metric Camera (1984, and Landsat TM/ETM+ (1991, 2001, 2005, 2009. Manual adjustment was especially necessary for delineating the debris-covered glaciers and the glaciers on the panchromatic Hexagon data. In the years around 2001 the whole mountain range contained about 960 glaciers covering an area of 795.6 ± 22.3 km2 while the ice in the drainage basin of Nam Co covered 198.1 ± 5.6 km2. The median elevation of the glaciers was about 5800 m with the majority terminating around 5600 m. Five glaciers with debris-covered tongues terminated lower than 5200 m. The glacier area decreased by −6.1 ± 3% between 1976 and 2001. This is less than reported in previous studies based on the 1970s topographic maps and Landsat data from 2000. Glaciers continued to shrink during the period 2001–2009. No advancing glaciers were detected. Detailed length measurements for five glaciers indicated a retreat of around 10 m per year (1976–2009. Ice cover is higher south-east of the mountain ridge which reflects the windward direction to the monsoon. The temperature increase during the ablation period was probably the main driver of glacier wastage, but the complex glacier-climate interactions need further investigation.

  4. Petrographic and geochemical analyisis for determination of provenance of the Slovenj Gradec Miocene Basin fill (Western Central Paratethys)

    Science.gov (United States)

    Ivančič, Kristina; Trajanova, Mirka; Skaberne, Dragomir; Šmuc, Andrej

    2017-04-01

    The Slovenj Gradec Basin (SGB) is located in northern Slovenia between eastern margin of the Northern Karavanke and the western Pohorje Mts. Structurally, it belongs to Eastern Alps. It is filled with Miocene clastic sediments. Modal composition of sandstones was determined on thin sections by point-counter and presented with the QFL and QmFLt diagrams. Their geochemical composition was determined by classical method and by Inductively Coupled Plasma-Mass Spectrometry. Based on petrography, sedimentary fill of the SGB consists mostly of lithic grains and quartz, derived from metamorphic and carbonate rocks. Locally, fragments of granitoids occur. Binder consists of carbonate, subordinately quartz cement, and carbonate matrix. Recycled orogen (lithic and transitional recycled) provenance of the grains was determined. Geochemical composition shows that: - Sandstones from the SGB belong to the fields of shale, wacke, litharenite, arkose and subarkose (Pettijohn, 1972). - In the ternary diagram of weathering trends (cf. Nesbitt & Young 1984), the samples group near the CaO+Na2OAl2O3 conjunctive. Calculated minimum CIA (Fedo et al., 1995) is 40.06, indicating that the source rocks were not subjected to considerable weathering. - According to discriminant function (cf. Roser & Korsch, 1988) all samples from SGB originate from quartzose sedimentary rocks. - For determination of tectonic setting of source rocks (Verma & Armstrong-Altrin, 2013) the studied samples plot in the field of collision zone. - In the multidimensional discriminant function diagram for the discrimination of active and passive margin after Verma and Armstrong (2016), the samples plot into the field of passive margin. The data indicate that source rocks of the SGB sedimentary fill were derived from Eastern Alps and Southern Alps. It is suggested that SGB was detached from the Styrian and Mura-Zala Basins in the course of the Pohorje Mts. oblique transpressive uplift during the late Miocene to Pliocene

  5. Large-scale Watershed Modeling: NHDPlus Resolution with Achievable Conservation Scenarios in the Western Lake Erie Basin

    Science.gov (United States)

    Yen, H.; White, M. J.; Arnold, J. G.; Keitzer, S. C.; Johnson, M. V. V.; Atwood, J. D.; Daggupati, P.; Herbert, M. E.; Sowa, S. P.; Ludsin, S.; Robertson, D. M.; Srinivasan, R.; Rewa, C. A.

    2016-12-01

    By the substantial improvement of computer technology, large-scale watershed modeling has become practically feasible in conducting detailed investigations of hydrologic, sediment, and nutrient processes. In the Western Lake Erie Basin (WLEB), water quality issues caused by anthropogenic activities are not just interesting research subjects but, have implications related to human health and welfare, as well as ecological integrity, resistance, and resilience. In this study, the Soil and Water Assessment Tool (SWAT) and the finest resolution stream network, NHDPlus, were implemented on the WLEB to examine the interactions between achievable conservation scenarios with corresponding additional projected costs. During the calibration/validation processes, both hard (temporal) and soft (non-temporal) data were used to ensure the modeling outputs are coherent with actual watershed behavior. The results showed that widespread adoption of conservation practices intended to provide erosion control could deliver average reductions of sediment and nutrients without additional nutrient management changes. On the other hand, responses of nitrate (NO3) and dissolved inorganic phosphorus (DIP) dynamics may be different than responses of total nitrogen and total phosphorus dynamics under the same conservation practice. Model results also implied that fewer financial resources are required to achieve conservation goals if the goal is to achieve reductions in targeted watershed outputs (ex. NO3 or DIP) rather than aggregated outputs (ex. total nitrogen or total phosphorus). In addition, it was found that the model's capacity to simulate seasonal effects and responses to changing conservation adoption on a seasonal basis could provide a useful index to help alleviate additional cost through temporal targeting of conservation practices. Scientists, engineers, and stakeholders can take advantage of the work performed in this study as essential information while conducting policy

  6. Assessing linkages between spatial facies changes and dimensional variations of glaciers in the upper Indus Basin, western Himalaya

    Science.gov (United States)

    Ali, Iram; Shukla, Aparna; Romshoo, Shakil A.

    2017-05-01

    The present study provides an insight into the heterogeneous response of 45 glaciers in the Lidder and Sindh river basins, western Himalaya, and explores the linkages between glacier facies variability and changing glacier parameters. Results show that the region has undergone an overall deglaciation of 12 ± 1.5% (11.9 ± 1.4 km2) from 1996 to 2014. Fluctuations in the temperature and precipitation patterns seem to be the primary factor controlling the changes in glacier dimensions (R2 > 0.82 in all cases). Glacier facies changes suggest depletion in snow-ice cover ( 18 ± 2.3%) and an increase in ice-mixed debris ( 4 ± 1.4%), supraglacial debris ( 6 ± 1.5%), and periglacial debris ( 17 ± 1.2%). These glacier facies transitions are possibly the result of ice-melting; however, its relative rate and elevation decides the nature of facies conversion. An increase in the proportion of supraglacial debris has led to the conversion of 11 clean glaciers to sparsely debris-covered glaciers and 5 sparsely debris-covered glaciers to debris-covered glaciers. The size of the glaciers greatly influenced the rate of conversion of glaciers, and glaciers glaciers also experienced maximum shrinkage. Further, the glaciers with varying supraglacial debris cover respond differently, as sparsely debris-covered glaciers exhibit the highest rates of retreat (25 ± 7.3 m/y), followed by clean (23.7 ± 7.3 m/y) and debris-covered glaciers (13.1 ± 7.3 m/y). Thus, the findings of this work clearly show that the climate change driven dimensional changes of glaciers and variations in the spatial distribution of glacier facies have strong mutual control on each other.

  7. Variability of fine and coarse aerosol over the Western Mediterranean Basin during the Minerva 2015 research cruise campaign

    Science.gov (United States)

    Castagna, Jessica; Carbone, Francesco; Naccarato, Attilio; Moretti, Sacha; Esposito, Giulio; Bencardino, Mariantonia; D'Amore, Francesco; Sprovieri, Francesca; Pirrone, Nicola

    2016-04-01

    The Mediterranean Basin, due to its semi-enclosed configuration, is heavily affected by air pollution and it is becoming, in the last years, a region of particular interest of study for its implications regarding both health effects and environmental impacts. The area is surrounded by a densely populated as well as industrialized coast, and even affected by natural sources. So, it is important to know how the various sources contributes to increase air pollution levels and discriminate among them. With special regard to aerosol pollution, natural sources, like Saharan dust, volcanoes, and fires, as well as anthropogenic sources, such as industry, road and marine traffic, and fuel combustion from heating, can equally increase the values of this dangerous pollutant. While on the land we can find numerous monitoring sites, there are not continuous measurements on the sea. For this reason, since 2000 the Institute of Atmospheric Pollution of the National Research Council (CNR-IIA) is conducting regular oceanographic campaigns of measurements in the Mediterranean Sea. In this context, here we report the results obtained during the last cruise campaign, which took place in the Western Mediterranean sector and was conducted on-board the Italian research vessel Minerva during summer 2015 (from June 27th to July 13th). Fine (PM2.5) and Coarse (PM2.5-10) particulate size fractions were collected on PTFE membrane filters (Advantec MFS) and their mass concentrations determined gravimetrically. Successively, all the filters were digested with a mixture of HNO3/H2O2 in an microwaves digestion system and then analyzed by ICP-MS for the determination of the major and trace elements. Outcomes regarding the particulate mass concentration, the content and the distribution of the analyzed elements over both PM size fractions will be discussed taking into account potential contributing sources as well as different meteorological conditions.

  8. Baseline monitoring of the western Arctic Ocean estimates 20% of Canadian basin surface waters are undersaturated with respect to aragonite.

    Directory of Open Access Journals (Sweden)

    Lisa L Robbins

    Full Text Available Marine surface waters are being acidified due to uptake of anthropogenic carbon dioxide, resulting in surface ocean areas of undersaturation with respect to carbonate minerals, including aragonite. In the Arctic Ocean, acidification is expected to occur at an accelerated rate with respect to the global oceans, but a paucity of baseline data has limited our understanding of the extent of Arctic undersaturation and of regional variations in rates and causes. The lack of data has also hindered refinement of models aimed at projecting future trends of ocean acidification. Here, based on more than 34,000 data records collected in 2010 and 2011, we establish a baseline of inorganic carbon data (pH, total alkalinity, dissolved inorganic carbon, partial pressure of carbon dioxide, and aragonite saturation index for the western Arctic Ocean. This data set documents aragonite undersaturation in ≈ 20% of the surface waters of the combined Canada and Makarov basins, an area characterized by recent acceleration of sea ice loss. Conservative tracer studies using stable oxygen isotopic data from 307 sites show that while the entire surface of this area receives abundant freshwater from meteoric sources, freshwater from sea ice melt is most closely linked to the areas of carbonate mineral undersaturation. These data link the Arctic Ocean's largest area of aragonite undersaturation to sea ice melt and atmospheric CO2 absorption in areas of low buffering capacity. Some relatively supersaturated areas can be linked to localized biological activity. Collectively, these observations can be used to project trends of ocean acidification in higher latitude marine surface waters where inorganic carbon chemistry is largely influenced by sea ice meltwater.

  9. A new impulse-stage sand fracturing technology and its pilot application in the western Sichuan Basin

    Directory of Open Access Journals (Sweden)

    Bin Qi

    2015-03-01

    Full Text Available A better placement of proppants has been always the goal pursued in sand fracturing in order to get longer effective fractures and higher flow conductivity. However, it is always difficult to achieve satisfactory effects by conventional processes. On the basis of theoretical analysis and simulation with FracproPT software, basic experiments, and innovative physical modeling experiment, a new impulse-stage fracturing process has been developed by combining a special pumping process with fiber, liquid and other auxiliary engineering means. Compared with conventional fracturing, the open seepage channel created by the new fracturing process has an obvious edge in effective fracture length and flow conductivity. Moreover, the open seepage channel can also improve fracture cleanliness and reduce pressure loss in artificial fractures, thus reaching the goal of prolonging the single-well production time and maximizing productivity. After the research on principles and optimal design of this new process, on-site pilot test and detailed post-fracturing evaluation were conducted. The results indicated that (1 the new process is highly operable and feasible; (2 compared with the adjacent wells with similar geological conditions, the proppant' cost is reduced by 44%–47%, the ratio of effective fracture length to propped fracture length is increased by about 16%, the fracturing fluid recovery rate is up to 63% after 18 h in the test, and the normalized production is 1.9–2.3 times that of the adjacent wells; and (3 the new process can significantly lower the cost and enhance production. The process has a broad application prospect in shallow-middle sand gas reservoirs and shale gas reservoirs in western Sichuan Basin.

  10. Suspended sediment, turbidity, and stream water temperature in the Sauk River Basin, western Washington, water years 2012-16

    Science.gov (United States)

    Jaeger, Kristin L.; Curran, Christopher A.; Anderson, Scott W.; Morris, Scott T.; Moran, Patrick W.; Reams, Katherine A.

    2017-11-01

    The Sauk River is a federally designated Wild and Scenic River that drains a relatively undisturbed landscape along the western slope of the North Cascade Mountain Range, Washington, which includes the glaciated volcano, Glacier Peak. Naturally high sediment loads characteristic of basins draining volcanoes like Glacier Peak make the Sauk River a dominant contributor of sediment to the downstream main stem river, the Skagit River. Additionally, the Sauk River serves as important spawning and rearing habitat for several salmonid species in the greater Skagit River system. Because of the importance of sediment to morphology, flow-conveyance, and ecosystem condition, there is interest in understanding the magnitude and timing of suspended sediment and turbidity from the Sauk River system and its principal tributaries, the White Chuck and Suiattle Rivers, to the Skagit River.Suspended-sediment measurements, turbidity data, and water temperature data were collected at two U.S. Geological Survey streamgages in the upper and middle reaches of the Sauk River over a 4-year period extending from October 2011 to September 2015, and at a downstream location in the lower river for a 5-year period extending from October 2011 to September 2016. Over the collective 5-year study period, mean annual suspended-sediment loads at the three streamgages on the upper, middle, and lower Sauk River streamgages were 94,200 metric tons (t), 203,000 t, and 940,000 t streamgages, respectively. Fine (smaller than 0.0625 millimeter) total suspended-sediment load averaged 49 percent at the upper Sauk River streamgage, 42 percent at the middle Sauk River streamgage, and 34 percent at the lower Sauk River streamgage.

  11. Constraining the Geological Time Scale for the Upper Cretaceous in the Edmonton Group: Western Canadian Sedimentary Basin

    Science.gov (United States)

    Heredia, B.; Gaylor, J. R.; Hilgen, F.; Kuiper, K.; Mezger, K.; Wijbrans, J. R.; Quidelleur, X.; Huesing, S.

    2011-12-01

    The Cretaceous period records evidence of sea-level changes, remarkably cyclic sedimentation, major perturbations in carbon cycles during anoxic events, and large scale igneous activity. Astronomically-tuned time scales are only partially consistent with recalculated Ar-Ar constraints for the Cretaceous-Paleogene (K-Pg) boundary, but differ in number and tuning of 405-kyr eccentricity related cycles. The exposures of Upper Cretaceous strata along the Red Deer River (Western Canadian Sedimentary Basin) offer a unique opportunity to examine aspects of marine, tectonic, and climatic influenced sediments. The uppermost part of the Knudsen Farm section is a well-preserved continuous section, mainly composed by climatically controlled alternations of silt and organic rich horizons, in which altered volcanic ash layers have been deposited. In this section, the K-Pg boundary has been placed at the base of a prominent coal layer (Nevis coal), approx. 24 m from the base of the c29r. We present a compilation of paleomagnetic data, chemical, colour and magnetic susceptibility proxies, and Ar-Ar, K-Ar and U-Pb (CA-TIMS) for the uppermost part of the Maastrichtian, including the base of the c29r to the K-Pg boundary and up to the lowermost Danian. High-resolution radioisotopic ages and the multi-proxy lithological and geochemical datasets are used to develop a cyclostratigraphic reconstruction of this interval, thus permitting the synchronisation of rock clocks close to the K-Pg boundary. This research is funded by the European Community's Seventh Framework Program (FP7/2007-2013) under grant agreement no [215458].

  12. Rainwater harvesting possibility under climate change: A basin-scale case study over western province of Saudi Arabia

    Science.gov (United States)

    Almazroui, Mansour; Islam, M. Nazrul; Balkhair, Khaled S.; Şen, Zekâi; Masood, Amjad

    2017-06-01

    Groundwater reservoirs are important water resources all over the world. Especially, they are of utmost significance for arid and semi-arid regions, and therefore, a sustainable exploitation of these reservoirs needs to be ensured. The natural and most exclusive water supplier to groundwater reservoirs in Saudi Arabia is rainfall, which is characterized by sporadic and random temporal and spatial distributions, particularly under the impacts of climate change; giving rise to uncertainty in groundwater recharge quantification. Although in Saudi Arabia, intense and frequent rainfall events are rare, but they generate significant flash floods with huge amounts of surface water. Under such circumstances, any simple but effective water storage augmentation facility such as rainwater harvesting (RWH) structures gain vital importance for sustainability of water supply and survivals in arid and semi-arid regions. The objective of this study is to explore the possibility of RWH over a basin in the western province of Saudi Arabia called Wadi Al-Lith under climate change. Climatic data is obtained from the IPCC AR5 GCMs, which is further downscaled using a regional climate model RegCM4 for the Arabian Peninsula domain. The RegCM4 is driven to simulate climatic parameters including rainfall at 25 km grid resolution for the present climate (1971-2000), and future climate (2006-2099) with representative concentration pathways, RCP4.5 and RCP8.5. Results indicate that more durable and longer wet durations are expected with increasing surplus rainfall amounts in the far future because of climate change impacts. Consequently, future climate scenarios are expected to enhance floods and flash floods occurrences, which call for progressive measures to harness the RWH opportunity.

  13. A new troodontid theropod, Talos sampsoni gen. et sp. nov., from the Upper Cretaceous Western Interior Basin of North America.

    Directory of Open Access Journals (Sweden)

    Lindsay E Zanno

    Full Text Available BACKGROUND: Troodontids are a predominantly small-bodied group of feathered theropod dinosaurs notable for their close evolutionary relationship with Avialae. Despite a diverse Asian representation with remarkable growth in recent years, the North American record of the clade remains poor, with only one controversial species--Troodon formosus--presently known from substantial skeletal remains. METHODOLOGY/PRINCIPAL FINDINGS: Here we report a gracile new troodontid theropod--Talos sampsoni gen. et sp. nov.--from the Upper Cretaceous Kaiparowits Formation, Utah, USA, representing one of the most complete troodontid skeletons described from North America to date. Histological assessment of the holotype specimen indicates that the adult body size of Talos was notably smaller than that of the contemporary genus Troodon. Phylogenetic analysis recovers Talos as a member of a derived, latest Cretaceous subclade, minimally containing Troodon, Saurornithoides, and Zanabazar. MicroCT scans reveal extreme pathological remodeling on pedal phalanx II-1 of the holotype specimen likely resulting from physical trauma and subsequent infectious processes. CONCLUSION/SIGNIFICANCE: Talos sampsoni adds to the singularity of the Kaiparowits Formation dinosaur fauna, which is represented by at least 10 previously unrecognized species including the recently named ceratopsids Utahceratops and Kosmoceratops, the hadrosaurine Gryposaurus monumentensis, the tyrannosaurid Teratophoneus, and the oviraptorosaurian Hagryphus. The presence of a distinct troodontid taxon in the Kaiparowits Formation supports the hypothesis that late Campanian dinosaurs of the Western Interior Basin exhibited restricted geographic ranges and suggests that the taxonomic diversity of Late Cretaceous troodontids from North America is currently underestimated. An apparent traumatic injury to the foot of Talos with evidence of subsequent healing sheds new light on the paleobiology of deinonychosaurians

  14. Estimated Avian Nest Loss Associated with Oil and Gas Exploration and Extraction in the Western Canadian Sedimentary Basin

    Directory of Open Access Journals (Sweden)

    Steven L. Van Wilgenburg

    2013-12-01

    Full Text Available Annual mortality within bird populations can be attributed to numerous sources; however, the extent to which anthropogenic sources of mortality contribute to avian demography is largely unknown. Quantifying the relative magnitude of human-related avian mortality could inform conservation efforts, particularly if multiple sources of human-related mortality can be contrasted. The unintentional destruction of nests and their contents by industrial activities conducted during the breeding season of resident and migratory birds presumably leads to one such source of human-caused avian mortality. As part of a broader effort to quantify major sources of human-related avian mortality, we estimated the magnitude of nest loss resulting from the terrestrial oil and gas sector in Canada, including: (1 seismic exploration, (2 pipeline right-of-way clearing, (3 well pad clearing, and (4 oil sands mining within the Western Canadian Sedimentary Basin (WCSB. We estimated nest losses as the product of estimated nest densities, the area disturbed annually, and the proportion of annual disturbance presumed to occur during the breeding season. The estimated number of nests disturbed annually by all oil and gas sectors combined ranged between 11,840 - 60,380. Interannual variation in exploration and extraction, and uncertainty in nest densities and the proportion of the disturbances occurring during the breeding season contributed to the variation. Accounting for natural mortality suggests an estimated loss of 10,200 - 41,150 (range potential recruits into the migratory bird population in a subsequent year. Although nest destruction is only one small component of the potential impacts of the oil and gas industry upon avian populations, these estimates establish a baseline for comparison with other sources of human-caused avian mortality. Models are now needed to compare nest losses against the legacy effects of oil and gas sector habitat disturbances and associated

  15. Basin characteristics, history of stream gaging, and statistical summary of selected streamflow records for the Rapid Creek basin, western South Dakota

    Science.gov (United States)

    Driscoll, Daniel G.; Zogorski, John S.

    1990-01-01

    The report presents a summary of basin characteristics affecting streamflow, a history of the U.S. Geological Survey 's stream-gaging program, and a compilation of discharge records and statistical summaries for selected sites within the Rapid Creek basin. It is the first in a series which will investigate surface-water/groundwater relations along Rapid Creek. The summary of basin characteristics includes descriptions of the geology and hydrogeology, physiography and climate, land use and vegetation, reservoirs, and water use within the basin. A recounting of the U.S. Geological Survey 's stream-gaging program and a tabulation of historic stream-gaging stations within the basin are furnished. A compilation of monthly and annual mean discharge values for nine currently operated, long-term, continuous-record, streamflow-gaging stations on Rapid Creek is presented. The statistical summary for each site includes summary statistics on monthly and annual mean values, correlation matrix for monthly values, serial correlation for 1 year lag for monthly values, percentile rankings for monthly and annual mean values, low and high value tables, duration curves, and peak-discharge tables. Records of monthend contents for two reservoirs within the basin also are presented. (USGS)

  16. Early 21st century climatology of snow cover for the western river basins of the Indus River System: effects of changes on hydrological balance and society.

    Science.gov (United States)

    Hasson, Shabeh; Lucarini, Valerio; Riaz Khan, Mobushir; Petitta, Marcello; Bolch, Tobias; Gioli, Giovanna

    2014-05-01

    In this study we assess the snow cover and its dynamics for the western river basins of the Indus River System (IRS) and their sub-basins located in Afghanistan, China, India and Pakistan for the period 2001-2012. Moderate Resolution Imaging Spectro-radiometer (MODIS) daily snow products from Terra (MOD) and Aqua (MYD) have been first improved and then analysed on seasonal and annual basis against different topographic parameters (aspect, elevation and slope). Our applied cloud filtering technique has reduced the cloud cover from 37% (MOD) and 43% (MYD) to 7%, thus improving snow cover estimates from 7% (MOD) and 5% (MYD) to 14% for the area of interest (AOI) during the validation period (2004). Our results show a decreasing tendency for the annual average snow cover for the westerlies-influenced basins (Upper Indus Basin, Astore, Hunza, Shigar, Shyok) and an increasing tendency for the monsoon-influenced basins (Jhelum, Kabul, Swat and Gilgit). Regarding the seasonal snow cover, decrease during winter and autumn and increase during spring and summer has been found, which is consistent with the observed cooling and warming trends during the respective seasons. Sub-basins at relatively higher latitude/altitude show higher variability than basins at lower latitude/mid-altitude. Northeastern and northwestern aspects feature larger snow cover. The mean regional snow line altitude (SLA) zones range between 3000 and 5000 m a.s.l. for all basins. Our analysis provides an indication of a decrease in the regional SLA zone, thus indicating a change in the water resources of the studied basins, particularly for the Upper Indus Basin (UIB). Such results are consistent with the observed hydro-climate data, recently collected local perceptions and glacier mass balances for the investigated period. Moreover, our analysis suggests some potential for the seasonal stream flow forecast as a significant negative correlation has been detected for the inter-annual variability of winter

  17. Bacteria diversity and microbial biomass in forest, pasture and fallow soils in the southwestern Amazon basin Diversidade de bacteria e biomassa microbiana em solos sob floresta, pastagem e capoeira no sudoeste da Amazônia

    OpenAIRE

    Karina Cenciani; Marcio Rodrigues Lambais; Carlos Clemente Cerri; Lucas Carvalho Basílio de Azevedo; Brigitte Josefine Feigl

    2009-01-01

    It is well-known that Amazon tropical forest soils contain high microbial biodiversity. However, anthropogenic actions of slash and burn, mainly for pasture establishment, induce profound changes in the well-balanced biogeochemical cycles. After a few years the grass yield usually declines, the pasture is abandoned and is transformed into a secondary vegetation called "capoeira" or fallow. The aim of this study was to examine how the clearing of Amazon rainforest for pasture affects: (1) the ...

  18. Evolution characteristic of gypsum-salt rocks of the upper member of Oligocene Lower Ganchaigou Fm in the Shizigou area, western Qaidam Basin

    Directory of Open Access Journals (Sweden)

    Dinghong Yi

    2017-09-01

    Full Text Available Over years of oil and gas exploration in the Qaidam Basin, reservoirs have been discovered in many layers. In the Shizigou area, western Qaidam Basin, the upper member of Oligocene Lower Ganchaigou Fm is an important target for oil and gas exploration, and gypsum-salt rocks are the high-quality caprocks for the preservation of oil and gas reservoirs in this area. For predicting oil and gas exploration direction and target in the western Qaidam Basin and providing guidance for its oil and gas exploration deployment, its depositional characteristics and environment of gypsum-salt rocks in this area were investigated based on the core observation, thin section identification, and analysis of grain size, sensitivity parameter ratios (Sr/Cu, Fe/Mn, (Fe + Al/(Ca + Mg, V/(V + Ni and Pr/Ph, pyrite content and inclusions. The following characteristics are identified. First, gypsum-salt rocks are mainly distributed in the depocenter of the lake basin and their thickness decreases towards the margin of the basin. They are laterally transformed into carbonate rocks or terrigenous clastic rocks. They are areally distributed in the shape of irregular ellipse. Second, gypsum-salt rocks are vertically developed mainly in the middle and upper parts of the upper member of Lower Ganchaigou Fm and they are interbedded with carbonate rocks or terrigenous clastic rocks. Their single layer thickness changes greatly, and there are many layers with good continuity. Third, Sand Group III to Group I in the upper member of Lower Ganchaigou Fm (inter-salt are of reductive water environment of semi-deep to deep lake facies due to their sedimentation in an arid and hot climate. It is concluded that gypsum-salt rocks of the upper member of Lower Ganchaigou Fm are distributed widely with great accumulative thickness in this area; and that they are originated from deep lake water by virtue of evaporation, concentration and crystallization in an arid and hot climate instead

  19. The Late Miocene to recent erosion pattern of the Alpine foreland basin reflects Eurasian slab-unloading beneath the western Alps rather than global climate change

    Science.gov (United States)

    Friedrich, Anke; Schlunegger, Fritz; Baran, Ramona

    2014-05-01

    It has been proposed that mountainous erosion increased globally around 5 Ma in response to global climate change, mainly because this increase coincides with a cooling trend indicated by global isotopic data (e.g., Herman et al. 2013). The Alps have played a prominent role in this debate. Published sedimentary budgets for the western and eastern Alps for the past 35 Ma show a substantial increase in the erosion of the Alps at c. 5 Ma (e.g., Kuhlemann, 2000). This temporal coincidence was used to call for a climate driver, mainly because this increase was not accompanied by tectonic convergence across the Alps during this time period. However, several authors emphasized the importance of lithospheric-scale processes beneath the Alps, which could also explain the increase in erosion rates through surface uplift. To provide a new perspective on this debate, we synthesized a spatial gradient map of erosion rates for the Alps and the entire Alpine foreland basin. Our data base consists of published (1) apatite fission-track (AFT) cooling ages for the Alps (e.g., Vernon et al. 2008; Luth and Willingshofer 2008; Wölfler et al. 2012; (2) AFT ages from wells from the Swiss foreland basin (e.g., Cederbom et al. 2011), and (3) stratigraphic data from industry wells in the German and Austrian foreland basin (e.g., Lemcke 1974; Genser et al. 2007). We focus our analysis on the shape and scale of the areas undergoing erosion since 5 Ma. Our synthesis of published denudation rate data for the past 5 Million years reveals that erosion of the Alpine foreland basin is highest in front of the western Alps (between 2 and 0.6 km), and decreases eastward over a distance of 700 km to the Austrian foreland basin (c. 200 m). For the western Alps, the compilation of apatite-fission-track ages yields erosion rates > 0.6 km/Ma, while erosion rates for the eastern foreland basin and the adjacent eastern Alps are slab along the Eurasian-Adriatic plate boundary. This mechanism triggered large

  20. Cancer among indigenous people in the Amazon basin of Ecuador, 1985-2000 El cáncer en la población indígena de la cuenca Amazónica del Ecuador, 1985-2000

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    Miguel San Sebastián

    2004-11-01

    Full Text Available OBJECTIVE: To provide some of the first data on cancer incidence among indigenous people in the Amazon basin of Ecuador, and to compare that incidence with the level found among nonindigenous persons living in that same area. METHODS: From the study area 1 207 cancer cases were reported to the National Cancer Registry over the 1985-2000 period. Frequency and relative risks were calculated for the indigenous residents and for the nonindigenous residents of the area. RESULTS: Cancer of the testes and leukemia were the most common cancer types among indigenous men, and cancer of the cervix uteri was the most common among indigenous women. Indigenous men were at significantly lower risk for cancer of the stomach, skin, prostate, and lymph nodes and for leukemia than were nonindigenous men. Indigenous women were at significantly lower risk for cancer of the stomach, skin, breast, cervix uteri, and lymph nodes than were nonindigenous women. CONCLUSION: Our data from the Ecuadorian Amazon indicate the need to develop appropriate mechanisms to register the indigenous population in the national census as well as in the National Cancer Registry. Also needed are cancer early detection programs, more health education efforts, and stronger health services that are adapted to the local conditions. Future research should focus on factors that may help to explain the different cancer patterns found among indigenous persons and nonindigenous persons.OBJETIVO: Proporcionar los primeros datos sobre la incidencia de cáncer en la población indígena de la cuenca amazónica del Ecuador y comparar dicha incidencia con la hallada en la población no indígena que habita en la misma zona. MÉTODOS: En la zona estudiada se notificaron 1 207 casos de cáncer al Registro Nacional de Cáncer en el período de 1985-2000. Se calcularon las respectivas frecuencias y riegos relativos de los residentes indígenas del territorio y de los residentes no indígenas. RESULTADOS: El

  1. Paleohydrogeology of the Canadian Rockies and origins of brines, Pb-Zn deposits and dolomitization in the Western Canada Sedimentary Basin

    Science.gov (United States)

    Nesbitt, Bruce E.; Muehlenbachs, Karlis

    1994-03-01

    Results of stable isotopic and fluid-inclusion studies of Cambrian carbonate units in the southern Canadian Rockies indicate that, during the Late Devonian or Early Mississippian, a warm brine migrated from miogeoclinal shales in the western part of the Western Canada Sedimentary Basin into the eastern carbonate sequences. This fluid had a temperature of 150 ±25 °C, salinity values of 20 to 25 equivalent wt% NaCl, and isotopic values of δ18O = -7‰ to 0‰,δ13C = -1‰ ±2‰, δD = -70‰ ±19‰, and 87Sr/86Sr >0.710. The fluids formed large bodies of coarse, sparry dolomite, as well as Pb-Zn, magnesite and talc mineralizations in the Cambrian units. It is probable that this event was also responsible for the development of Pb-Zn mineralization (specifically Pine Point) in the Devonian units, as well as a component of the present-day basinal brines in the basin.

  2. Cross section of the lower part of the upper Triassic in the western part of the Szechwan basin and situation of the sedimentation in these deposits. [China

    Energy Technology Data Exchange (ETDEWEB)

    Den, K.; Khe, Ch.; Khe, L.; Tsin, D.

    1982-01-01

    Depositing of the upper Triassic, developed very broadly (in contrast to the lower Triassic which are encountered sporadically) plays an important role in the oil and gas geology of the Szechwan basin. A detailed description is made (including lithology and community of minerals) of the cross section of the Maantan series. The series is 329 m thick. It is separated by nonconformities from the Tyantszinshan series (from the bottom) and Syaotantszy (from the top). Based on the encountered ammonites, foraminifera, spores and pollen, etc. the series is classified with the Karniyskiy stage. In the beginning of this century, the transgression of the Tetis Sea, extending to the southeast of the Aba-Gartsze region reached the western part of the basin. As a result, a series was deposited of mainly organogenic-detrital limestones. In the middle and late Karniyskiy time, the sea was extended further to the southeast. The admixture of terrigenous material is great in the deposits of the corresponding part of the series. From the data of studies, the western part of the Szechwan basin is compared with the eastern shelf of the Aba-Gartsze Sea.

  3. Programming Amazon EC2

    CERN Document Server

    Vliet, Jurg

    2011-01-01

    If you plan to use Amazon Web Services to run applications in the cloud, the end-to-end approach in this book will save you needless trial and error. You'll find practical guidelines for designing and building applications with Amazon Elastic Compute Cloud (EC2) and a host of supporting AWS tools, with a focus on critical issues such as load balancing, monitoring, and automation. How do you move an existing application to AWS, or design your application so that it scales effectively? How much storage will you require? Programming Amazon EC2 not only helps you get started, it will also keep y

  4. Provenance and detrital zircon geochronologic evolution of lower Brookian foreland basin deposits of the western Brooks Range, Alaska, and implications for early Brookian tectonism

    Science.gov (United States)

    Moore, Thomas; O'Sullivan, Paul B.; Potter, Christopher J.; Donelick, Raymond A.

    2015-01-01

    The Upper Jurassic and Lower Cretaceous part of the Brookian sequence of northern Alaska consists of syntectonic deposits shed from the north-directed, early Brookian orogenic belt. We employ sandstone petrography, detrital zircon U-Pb age analysis, and zircon fission-track double-dating methods to investigate these deposits in a succession of thin regional thrust sheets in the western Brooks Range and in the adjacent Colville foreland basin to determine sediment provenance, sedimentary dispersal patterns, and to reconstruct the evolution of the Brookian orogen. The oldest and structurally highest deposits are allochthonous Upper Jurassic volcanic arc–derived sandstones that rest on accreted ophiolitic and/or subduction assemblage mafic igneous rocks. These strata contain a nearly unimodal Late Jurassic zircon population and are interpreted to be a fragment of a forearc basin that was emplaced onto the Brooks Range during arc-continent collision. Synorogenic deposits found at structurally lower levels contain decreasing amounts of ophiolite and arc debris, Jurassic zircons, and increasing amounts of continentally derived sedimentary detritus accompanied by broadly distributed late Paleozoic and Triassic (359–200 Ma), early Paleozoic (542–359 Ma), and Paleoproterozoic (2000–1750 Ma) zircon populations. The zircon populations display fission-track evidence of cooling during the Brookian event and evidence of an earlier episode of cooling in the late Paleozoic and Triassic. Surprisingly, there is little evidence for erosion of the continental basement of Arctic Alaska, its Paleozoic sedimentary cover, or its hinterland metamorphic rocks in early foreland basin strata at any structural and/or stratigraphic level in the western Brooks Range. Detritus from exhumation of these sources did not arrive in the foreland basin until the middle or late Albian in the central part of the Colville Basin.These observations indicate that two primary provenance areas provided

  5. EXPANDING THE AREA OF DISTRIBUTION OF EUFRIESEA FRAGROCARA KIMSEY (HYMENOPTERA, APIDAE IN THE BRAZILIAN AMAZON FOREST

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    M. H. S. Souza

    2015-02-01

    Full Text Available The expansion of agriculture in the Arc of Deforestation causes deforestation and habitat loss. Euglossines sampling was done near Juruena River, Cotriguaçu municipality, northern Mato Grosso State. The bees were collected on understory and canopy using different baits. A total of 41 males of Eufriesea fragrocara Kimsey were collected. This is a rare species in collections and catalogued only in Huánuco (Peru, Napo (Ecuador, Ouro Preto D’Oeste and Ariquemes, Rondônia, Brazil. This new records increase the geographic distribution of E. fragrocara in 500 km to the western Amazon Basin, reducing the filling gaps in their distribution range in the Neotropics.

  6. The riverine source of CH4 and N2O from the Republic of Congo, western Congo Basin

    Science.gov (United States)

    Upstill-Goddard, Robert C.; Salter, Matthew E.; Mann, Paul J.; Barnes, Jonathan; Poulsen, John; Dinga, Bienvenu; Fiske, Gregory J.; Holmes, Robert M.

    2017-05-01

    We discuss concentrations of dissolved CH4, N2O, O2, NO3- and NH4+, and emission fluxes of CH4 and N2O for river sites in the western Congo Basin, Republic of Congo (ROC). Savannah, swamp forest and tropical forest samples were collected from the Congo main stem and seven of its tributaries during November 2010 (41 samples; wet season) and August 2011 (25 samples; dry season; CH4 and N2O only). Dissolved inorganic nitrogen (DIN: NH4++ NO3-; wet season) was dominated by NO3- (63 ± 19 % of DIN). Total DIN concentrations (1.5-45.3 µmol L-1) were consistent with the near absence of agricultural, domestic and industrial sources for all three land types. Dissolved O2 (wet season) was mostly undersaturated in swamp forest (36 ± 29 %) and tropical forest (77 ± 36 %) rivers but predominantly supersaturated in savannah rivers (100 ± 17 %). The dissolved concentrations of CH4 and N2O were within the range of values reported earlier for sub-Saharan African rivers. Dissolved CH4 was found to be supersaturated (11.2-9553 nmol L-1; 440-354 444 %), whereas N2O ranged from strong undersaturation to supersaturation (3.2-20.6 nmol L-1; 47-205 %). Evidently, rivers of the ROC are persistent local sources of CH4 and can be minor sources or sinks for N2O. During the dry season the mean and range of CH4 and N2O concentrations were quite similar for the three land types. Wet and dry season mean concentrations and ranges were not significant for N2O for any land type or for CH4 in savannah rivers. The latter observation is consistent with seasonal buffering of river discharge by an underlying sandstone aquifer. Significantly higher wet season CH4 concentrations in swamp and forest rivers suggest that CH4 can be derived from floating macrophytes during flooding and/or enhanced methanogenesis in adjacent flooded soils. Swamp rivers also exhibited both low (47 %) and high (205 %) N2O saturation but wet season values were overall significantly lower than in either tropical forest or

  7. Reservoir quality using the routine core analysis data of Abu Roash ;C; in Badr El Din-15 oil field, Abu Gharadig basin, north Western Desert, Egypt

    Science.gov (United States)

    Barakat, Moataz Kh.; Nooh, Ahmed Z.

    2017-05-01

    The Abu Gharadig basin is one of the most prolific basins in the northern part of the Western Desert, Egypt. It has attracted the attention of many geologists and geophysicists for oil and gas exploration. This is due to existence of the huge subsurface sedimentary section in the basin which includes important thickness of reservoir rocks. The study area occupies the northwestern part of Abu Gharadig basin between latitudes 29° 45‧ and 30° 05‧ N, and longitudes 27° 30‧ and 28° 10‧ E. The present work deals with the routine core analysis for petrophysical evaluation of the Abu Roash ;C; Member. The available core samples belong to BED 15-3 and BED 15-7 wells in BED 15 oil field. The conventional core analyses include laboratory measurement of density (grain and bulk), helium porosity and permeability (horizontal and vertical). The core analysis data indicate that Abu Roash ;C; Member in BED-15 oil field is characterized by good reservoir quality due to high values of porosity and permeability. The statistical analysis of core data can be used to generate new relations which help to determine one petrophysical parameters in term of other.

  8. Coordinated study of the Devonian black shale in the Illinois Basin: Illinois, Indiana, and western Kentucky. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lineback, J.A.

    1980-12-31

    An evaluation of the resource potential of the Devonian shales, called the Eastern Gas Shales Project (EGSP) was begun. A study of the stratigraphy, structure, composition, and gas content of the Devonian shale in the Illinois Basin was undertaken by the State Geological Surveys of Illinois, Indiana, and Kentucky, under contract to the U.S. DOE as a part of the EGSP. Certain additional data were also developed by other research organizations (including Monsanto Research Corporation-Mound Facility and Battelle-Columbus Laboratory) on cores taken from the Illinois Basin. This report, an overview of geological data on the Illinois basin and interpretations of this data resulting from the EGSP, highlights areas of potential interest as exploration targets for possible natural gas resources in the Devonian shale of the basin. The information in this report was compiled during the EGSP from open file data available at the three State Geological surveys and from new data developed on cores taken by the DOE from the basin specifically for the EGSP. The organically richest shale is found in southeastern Illinois and in most of the Indiana and Kentucky portions of the Illinois Basin. The organic-rich shales in the New Albany are thickest near the center of the basin in southeastern Illinois, southwestern Indiana, and adjacent parts of Kentucky portions of the Illinois Basin. The organic-rich shales in the New Albany are thickest near the center of the basin in southeastern Illinois, southwestern Indiana, and adjacent parts of Kentucky. Natural fractures in the shale may aid in collecting gas from a large volume of shale. These fractures may be more abundant and interconnected to a greater degree in the vicinity of major faults. Major faults along the Rough Creek Lineament and Wabash Valley Fault System cross the deeper part of the basin.

  9. Hydrochemical and stable isotope indicators of pyrite oxidation in carbonate-rich environment; the Hamersley Basin, Western Australia

    Science.gov (United States)

    Dogramaci, Shawan; McLean, Laura; Skrzypek, Grzegorz

    2017-02-01

    Sulphur (S) is a commonly occurring element in most aquifers, primarily in oxidised (sulphates) and reduced (sulphides) forms. Sulphides often constitute a risk to groundwater quality due to acid rock drainage, especially in catchments that are subject to mining excavations or groundwater injection. However, in semi-arid regions detection of the acid rock drainage risk can be challenging and traditional methods based on observations of increasing SO4 concentrations or SO4/Cl ratios in surface and groundwater, are not necessarily applicable. In addition, decreasing pH, usually accompanying pyrite oxidation, can be masked by the high pH-neutralisation capacity of carbonate and silicate minerals. Analysis of 73 surface and groundwater samples from different water bodies and aquifers located in the Hamersley Basin, Western Australia found that most of the samples are characterised by neutral pH but there was also a large spatial variability in the dissolved sulphate (SO4) concentrations that ranged from 1 mg/L to 15,000 mg/L. Not surprisingly, groundwater in aquifers that contained pyrite had high sulphate concentrations (>1000 mg/L). This was associated with low δ34SSO4 values (+1.2‰ to +4.6‰) and was consistent with the values obtained from aquifer matrix pyritic rock samples (-1.9‰ to +4.4‰). It was also found that the SO4 concentrations and acidity levels were not only dependent on δ34SSO4 values and existence of pyrite but also on the presence of carbonate minerals in the aquifer matrix. The groundwater in aquifers containing both pyrite and carbonate minerals had a neutral pH and was also saturated with respect to gypsum and had high magnesium concentrations of up to 2200 mg/L suggesting de-dolomitisation as the process buffering the acidity generated by pyrite oxidation. Based on the findings from this study, a classification scheme has been developed for identification of the acid rock drainage contribution to groundwater that encompasses a myriad of

  10. A pesca comercial na bacia do rio Madeira no estado de Rondônia, Amazônia brasileira The Commercial fisheries of the Madeira river basin in the Rondônia state, brazilian Amazon

    Directory of Open Access Journals (Sweden)

    Carolina Rodrigues da Costa Doria

    2012-03-01

    Full Text Available Este estudo caracteriza quali e quantitativamente a atividade pesqueira comercial na bacia do rio Madeira, afluente do rio Amazonas, no trecho entre Guajará-Mirim e Porto Velho, estado de Rondônia. No período de janeiro a dezembro/2004, foram registrados 460 t, correspondendo 935 viagens. A análise dos dados oriundos do monitoramento dos desembarques demonstrou que a pesca na região tem caráter artesanal de pequena escala, destacando a maior participação das canoas motorizadas (131 unidades do que barcos pesqueiros (45 unidades; capacidade média: 3.000kg na frota pesqueira. Os peixes migradores jaraqui (Semaprochilodus spp., dourada (Brachyplatystoma rousseauxii, sardinha (Triportheus spp., jatuarana/matrinxã (Brycon amazonicus e B. cephalus, curimatã (Prochilodus nigricans e filhote (Brachyplatystoma filamentosum se destacaram na composição das espécies desembarcadas. As informações técnicas geradas são importantes para subsidiar ações de ordenamento pesqueiro, bem como para avaliar futuras variações que possam ocorrer na atividade frente aos impactos dos empreendimentos hidrelétricos em construção na região.This study presents qualitative and quantitative information about commercial fishery in the basin of the Madeira River, tributary of the Amazon River, describing the fishing activity in the segment between Guajará-Mirim and Porto Velho, in Rondônia State. From January to December/2004, 219 fishermen and 935 trips were registered, corresponding to the capture of 460 t of fish. Data from fish landings demonstrate that fisheries in the region are small-scaled and point to a higher participation of small motorized canoes (130 units than of fishing boats (45 units; average capacity: 3000 kg in the fishing fleet. Migratory species like jaraqui (Semaprochilodus spp., dourada (Brachyplatystoma rousseauxii, sardinha (Triportheus spp., jatuarana/matrinxã (Brycon amazonicus e B. cephalus, curimatã (Prochilodus nigricans

  11. Is Chicxulub Too Small to be the Source of the K/Pg Boundary Layer and the Cause of the Dinosaur Extinction Event and would the Amazon Basin Considered as an Impact Feature fit the Evidence Better?

    Science.gov (United States)

    Burgener, J. A.

    2016-12-01

    challenges of Chicxulub as long as it was near the location of Chicxulub. If the Amazon Basin was considered as an impact, it would be large enough to fit the K/Pg boundary layer details much better than Chicxulub, and it would explain the extinction event without any need to rely on extenuating factors - the impact itself would have been sufficient to cause the extinction.

  12. Sex determination in the Giant fish of Amazon Basin, Arapaima gigas (Osteoglossiformes, Arapaimatidae, using laparoscopy Determinação do sexo no peixe gigante da Bacia Amazônica, Arapaima gigas (Osteoglossiformes, Arapaimatidae, usando laparoscopia

    Directory of Open Access Journals (Sweden)

    Carlos Riedel Porto Carreiro

    2011-01-01

    Full Text Available The Giant of Amazon basin, pirarucu, Arapaima gigas, is the largest scaled freshwater fish in the world. pirarucu cultivation has recently started, driven by the decline in natural populations and high market value. Currently, there are no reliable methods for sexual differentiation in this species other than direct examination of gonads, which requires dissection of specimens. A non-lethal and less invasive method for sexual identification is highly desirable in order to properly group broodstock for mating and offspring production. We utilized laparoscopic examination in anesthetized pirarucu to differentiate between male and female individuals. This method allowed for the observation and differentiation of the reproductive organs within an individual. Our results suggest that laparoscopy is an efficient method for sex differentiation in pirarucu causing minimal stress to the fish.O gigante da bacia amazônica, pirarucu, Arapaima gigas, é o maior peixe de escamas de água doce do mundo. O seu cultivo teve início recentemente motivado pelo declínio de suas populações naturais em virtude do alto valor de sua carne no mercado. Não existem métodos para a diferenciação sexual nesta espécie, o único método é o exame direto das gônadas, o qual requer a dissecação do espécime. Um método para a identifica��ão sexual é altamente desejável, a fim de selecionar grupos de reprodutores para o acasalamento e, portanto, a produção de progênie. A fim de diferenciar reprodutores machos de fêmeas, foi utilizado o exame laparoscópico em animais previamente anestesiados. Este método permitiu a observação dos órgãos abdominais, incluindo gônadas, com grande precisão. Os resultados mostram que a laparoscopia é um método eficiente para a diferenciação do sexo em pirarucu e causam o mínimo de stress para os animais.

  13. Distribution of Artisanal and Small-Scale Gold Mining in the Tapajós River Basin (Brazilian Amazon over the Past 40 Years and Relationship with Water Siltation

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    Felipe de Lucia Lobo

    2016-07-01

    Full Text Available An innovative remote sensing approach that combines land-use change and water quality information is proposed in order to investigate if Artisanal and Small-scale Gold Mining (ASGM area extension is associated with water siltation in the Tapajós River Basin (Brazil, containing the largest small-scale gold mining district in the world. Taking advantage of a 40-year period of the multi-satellite imagery archive, the objective of this paper is to build a normalized time-series in order to evaluate the influence of temporal mining expansion on the water siltation data (TSS, Total Suspended Solids concentration derived from previous research. The methodological approach was set to deliver a full characterization of the ASGM expansion from its initial stages in the early 1970s to the present. First, based on IRS/LISSIII images acquired in 2012, the historical Landsat image database (1973–2001 was corrected for radiometric and atmospheric effects using dark vegetation as reference to create a normalized time-series. Next, a complete update of the mining areas distribution in 2012 derived from the TerraClass Project (an official land-use classification for the Brazilian Amazon was conducted having IRS/LISSIII as the base map with the support of auxiliary data and vector editing. Once the ASGM in 2012 was quantified (261.7 km2 and validated with photos, a reverse classification of ASGM in 2001 (171.7 km2, 1993 (166.3 km2, 1984 (47.5 km2, and 1973 (15.4 km2 with the use of Landsat archives was applied. This procedure relies on the assumption that ASGM changes in the land cover are severe and remain detectable from satellite sensors for decades. The mining expansion area over time was then combined with the (TSS data retrieved from the same atmospherically corrected satellite imagery based on the literature. In terms of gold mining expansion and water siltation effects, four main periods of ASGM activities were identified in the study area: (i 1958

  14. Introduction: Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5

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    S. T. Martin

    2016-04-01

    Full Text Available The Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5 Experiment was carried out in the environs of Manaus, Brazil, in the central region of the Amazon basin for 2 years from 1 January 2014 through 31 December 2015. The experiment focused on the complex interactions among vegetation, atmospheric chemistry, and aerosol production on the one hand and their connections to aerosols, clouds, and precipitation on the other. The objective was to understand and quantify these linked processes, first under natural conditions to obtain a baseline and second when altered by the effects of human activities. To this end, the pollution plume from the Manaus metropolis, superimposed on the background conditions of the central Amazon basin, served as a natural laboratory. The present paper, as the introduction to the special issue of GoAmazon2014/5, presents the context and motivation of the GoAmazon2014/5 Experiment. The nine research sites, including the characteristics and instrumentation of each site, are presented. The sites range from time point zero (T0 upwind of the pollution, to T1 in the midst of the pollution, to T2 just downwind of the pollution, to T3 furthest downwind of the pollution (70 km. In addition to the ground sites, a low-altitude G-159 Gulfstream I (G-1 observed the atmospheric boundary layer and low clouds, and a high-altitude Gulfstream G550 (HALO operated in the free troposphere. During the 2-year experiment, two Intensive Operating Periods (IOP1 and IOP2 also took place that included additional specialized research instrumentation at the ground sites as well as flights of the two aircraft. GoAmazon2014/5 IOP1 was carried out from 1 February to 31 March 2014 in the wet season. GoAmazon2014/5 IOP2 was conducted from 15 August to 15 October 2014 in the dry season. The G-1 aircraft flew during both IOP1 and IOP2, and the HALO aircraft flew during IOP2. In the context of the Amazon basin, the two IOPs also

  15. Lithosphere, crust and basement ridges across Ganga and Indus basins and seismicity along the Himalayan front, India and Western Fold Belt, Pakistan

    Science.gov (United States)

    Ravi Kumar, M.; Mishra, D. C.; Singh, B.

    2013-10-01

    Spectral analysis of the digital data of the Bouguer anomaly of North India including Ganga basin suggest a four layer model with approximate depths of 140, 38, 16 and 7 km. They apparently represent lithosphere-asthenosphere boundary (LAB), Moho, lower crust, and maximum depth to the basement in foredeeps, respectively. The Airy's root model of Moho from the topographic data and modeling of Bouguer anomaly constrained from the available seismic information suggest changes in the lithospheric and crustal thicknesses from ˜126-134 and ˜32-35 km under the Central Ganga basin to ˜132 and ˜38 km towards the south and 163 and ˜40 km towards the north, respectively. It has clearly brought out the lithospheric flexure and related crustal bulge under the Ganga basin due to the Himalaya. Airy's root model and modeling along a profile (SE-NW) across the Indus basin and the Western Fold Belt (WFB), (Sibi Syntaxis, Pakistan) also suggest similar crustal bulge related to lithospheric flexure due to the WFB with crustal thickness of 33 km in the central part and 38 and 56 km towards the SE and the NW, respectively. It has also shown the high density lower crust and Bela ophiolite along the Chamman fault. The two flexures interact along the Western Syntaxis and Hazara seismic zone where several large/great earthquakes including 2005 Kashmir earthquake was reported. The residual Bouguer anomaly maps of the Indus and the Ganga basins have delineated several basement ridges whose interaction with the Himalaya and the WFB, respectively have caused seismic activity including some large/great earthquakes. Some significant ridges across the Indus basin are (i) Delhi-Lahore-Sargodha, (ii) Jaisalmer-Sibi Syntaxis which is highly seismogenic. and (iii) Kachchh-Karachi arc-Kirthar thrust leading to Sibi Syntaxis. Most of the basement ridges of the Ganga basin are oriented NE-SW that are as follows (i) Jaisalmer-Ganganagar and Jodhpur-Chandigarh ridges across the Ganga basin intersect

  16. Aquatic Biodiversity in the Amazon: Habitat Specialization and Geographic Isolation Promote Species Richness

    Directory of Open Access Journals (Sweden)

    Roberto E. Reis

    2011-04-01

    Full Text Available The Neotropical freshwater ichthyofauna has among the highest species richness and density of any vertebrate fauna on Earth, with more than 5,600 species compressed into less than 12% of the world’s land surface area, and less than 0.002% of the world’s total liquid water supply. How have so many species come to co-exist in such a small amount of total habitat space? Here we report results of an aquatic faunal survey of the Fitzcarrald region in southeastern Peru, an area of low-elevation upland (200–500 m above sea level rainforest in the Western Amazon, that straddles the headwaters of four large Amazonian tributaries; the Juruá (Yurúa, Ucayali, Purús, and Madre de Dios rivers. All measures of fish species diversity in this region are high; there is high alpha diversity with many species coexisting in the same locality, high beta diversity with high turnover between habitats, and high gamma diversity with high turnover between adjacent tributary basins. Current data show little species endemism, and no known examples of sympatric sister species, within the Fitzcarrald region, suggesting a lack of localized or recent adaptive divergences. These results support the hypothesis that the fish species of the Fitzcarrald region are relatively ancient, predating the Late Miocene-Pliocene (c. 4 Ma uplift that isolated its several headwater basins. The results also suggest that habitat specialization (phylogenetic niche conservatism and geographic isolation (dispersal limitation have contributed to the maintenance of high species richness in this region of the Amazon Basin.

  17. Aquatic Biodiversity in the Amazon: Habitat Specialization and Geographic Isolation Promote Species Richness.

    Science.gov (United States)

    Albert, James S; Carvalho, Tiago P; Petry, Paulo; Holder, Meghan A; Maxime, Emmanuel L; Espino, Jessica; Corahua, Isabel; Quispe, Roberto; Rengifo, Blanca; Ortega, Hernan; Reis, Roberto E

    2011-04-29

    The Neotropical freshwater ichthyofauna has among the highest species richness and density of any vertebrate fauna on Earth, with more than 5,600 species compressed into less than 12% of the world's land surface area, and less than 0.002% of the world's total liquid water supply. How have so many species come to co-exist in such a small amount of total habitat space? Here we report results of an aquatic faunal survey of the Fitzcarrald region in southeastern Peru, an area of low-elevation upland (200-500 m above sea level) rainforest in the Western Amazon, that straddles the headwaters of four large Amazonian tributaries; the Juruá (Yurúa), Ucayali, Purús, and Madre de Dios rivers. All measures of fish species diversity in this region are high; there is high alpha diversity with many species coexisting in the same locality, high beta diversity with high turnover between habitats, and high gamma diversity with high turnover between adjacent tributary basins. Current data show little species endemism, and no known examples of sympatric sister species, within the Fitzcarrald region, suggesting a lack of localized or recent adaptive divergences. These results support the hypothesis that the fish species of the Fitzcarrald region are relatively ancient, predating the Late Miocene-Pliocene (c. 4 Ma) uplift that isolated its several headwater basins. The results also suggest that habitat specialization (phylogenetic niche conservatism) and geographic isolation (dispersal limitation) have contributed to the maintenance of high species richness in this region of the Amazon Basin.

  18. From rifting to spreading - seismic structure of the rifted western Mariana extinct arc and the ParceVela back-arc basin

    Science.gov (United States)

    Grevemeyer, Ingo; Kodaira, Shuichi; Fujie, Gou; Takahashi, Narumi

    2017-04-01

    The proto Izu-Ogasawara (Bonin)-Mariana (IBM) Island arc was created when subduction of the Pacific plate began during the Eocene. Today, the Kyushu-Palau Ridge (KPR) at the centre of the Philippine Sea and the western Mariana Ridge (WMR) are considered to be a remnant of the proto IBM Island arc. The KPR and WMR were separated when back-arc spreading began at 30 to 29 Ma in the Shikoku Basin and ParceVela Basin (PVB). Volcanic activity along the arcs diminished at 27 Ma and there is little evidence of volcanic activity between 23-17 Ma. Arc volcanism was reactivated at 15 Ma, when the opening of the Shikoku Basin and PVB ceased. At about 5 Ma the Mariana Basin opened, rifting the WMR from the Mariana arc. Here, we report results from the seismic refraction and wide-angle profile MR101c shot in summer of 2003 by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) aboard the RV KAIYO during the cruise KY03-06, extending from the PVB across the WMR and terminating just to the east of the WMR. Along MR101c 46 OBS recorded shots from an airgun array of 12,000 cubic inches (197 litres); 44 OBS provided excellent P-wave data, including arrivals sampling the crust (Pg), the crust/mantle boundary (PmP), the uppermost mantle (Pn) and a deep reflection (PnP) under the WMR. To yield the seismic velocity structure, we used a joint reflection and refraction tomography, revealing the crustal and mantle P-wave velocity structure, the seismic Moho, and a deep-seated reflector. Distinct features are a 14 km thick crust forming the WMR, a high-velocity lower crust in both transition zones to the ParceVela Basin and Mariana Basin, and a reflector at 24 km depth, which shallows to 18 km in the transition zone to the Mariana Basin, perhaps reflecting rifting-related thinning of the entire lithosphere. The deep-reflector, however, did not occur under the PVB. Upper mantle velocity below the WMR is 8 km/s. However, with respect to oceanic crust sampled in the Pacific Basin

  19. Contributions to the phytocoenological study of pure european beech forests in Oraştie river basin (central-western Romania)

    OpenAIRE

    Petru BURESCU; Valeriu Ioan VINŢAN

    2012-01-01

    În the current paper we present a phytocoenologic study of the phytocoenoses of the association Festuco drymejaeFagetum Morariu et al. 1968 (Syn.: Fagetum sylvaticae transylvaticum facies with Festuca drymeja I. Pop et al. 1974), found in the pure European beech fores