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Sample records for central amazon basin

  1. Dissolved organic matter and terrestrial-lotic linkages in the Central Amazon Basin of Brazil

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    McClain, Michael E.; Richey, Jeffrey E.; Brandes, Jay A.; Pimentel, Tania P.

    1997-09-01

    We evaluate the hypothesis that decomposition and adsorption reactions operating in upland soils of headwater catchments control the concentration and composition of dissolved and fine particulate organic matter in rivers of the Amazon basin. In two contrasting first-order catchments characteristic of the central Amazon basin, we analyzed plant, litter, soil, groundwater, and stream water chemistry. Our results indicate that clear and persistent differences exist in the concentration and elemental composition of dissolved organic matter (DOM) in stream waters and groundwaters from the two catchments, due mainly to corresponding differences in soil texture and chemistry. Within the more oxide and clay rich Oxisols underlying terra firme forest, groundwater DOM concentrations were uniformly low (120 μMC) and C/N ratios averaged 10. Conversely, within the oxide and clay deficient Spodosols underlying campinarana forest, groundwater DOM concentrations were greatly elevated (3000 μMC), and C/N ratios averaged near 60. We found that, in the terra firme/Oxisol terrain, the majority of DOM contributions to the stream derived from the riparian zone, while in the campinarana/Spodosol terrain, upland groundwater contributions could account for the concentration and composition of DOM in the stream. The implications of our findings are that in the terra firme terrains which dominate the region, upland soil profiles are not the site of definitive processes which impart compositional signatures to organic matter carried by the largest rivers of the Amazon basin, as was hypothesized. Instead, we suggest that definitive reactions are focused primarily in the river corridor.

  2. Spatial and seasonal contrasts of sedimentary organic matter in floodplain lakes of the central Amazon basin

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    Sobrinho, R. L.; Bernardes, M. C.; Abril, G.; Kim, J.-H.; Zell, C. I.; Mortillaro, J.-M.; Meziane, T.; Moreira-Turcq, P.; Sinninghe Damsté, J. S.

    2016-01-01

    In this study, we investigated the seasonal and spatial pattern of sedimentary organic matter (SOM) in five floodplain lakes of the central Amazon basin (Cabaliana, Janauaca, Canaçari, Mirituba and Curuai) which have different morphologies, hydrodynamics and vegetation coverages. 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 the C : N ratio and the stable isotopic composition of organic carbon (δ13Corg). These results were compared with lignin phenol parameters as an indicator of vascular plant detritus and branched glycerol dialkyl glycerol tetraethers (brGDGTs) to trace the input of soil organic matter (OM) from land to the aquatic settings. We also applied the crenarchaeol as an indicator of aquatic (rivers and lakes) OM. Our data showed that during the RW and FW seasons, the surface sediments were enriched in lignin and brGDGTs in comparison to other seasons. Our study also indicated that floodplain lake sediments primarily consisted of allochthonous, C3 plant-derived OM. However, a downstream increase in C4 macrophyte-derived OM contribution was observed along the gradient of increasing open waters - i.e., from upstream to downstream. Accordingly, we attribute the temporal and spatial difference in SOM composition to the hydrological dynamics between the floodplain lakes and the surrounding flooded forests.

  3. Late quaternary pollen records from the middle caqueta river basin in central colombian amazon

    International Nuclear Information System (INIS)

    Three pollen records are presented from the Pantano de Monica region (0 degrade 42' S, 72 degrade 04' W, 160 m elevation) on the lower terrace of Caqueta River of the central Colombian Amazonas. Ten radiocarbon dates from three cores indicate that the deposits are of Holocene age, but the pollen data suggest that also the record may contain the late glacial. The core Pantano de Monica 1 covers the time interval from 11,150 BP (extrapolated) to 4730 BP during the late glacial and early Holocene this swamp was smaller in size and water were more shallow than today, with abundant Mauritia palm trees. This indicates that the lower terrace of the Caqueta River was better drained than today, which might be related to changes in the drainage system and/or drier conditions during that time. Late glacial and early Holocene vegetation changes in the rain forests surrounding the swamp Pantano de Monica indicate successional stages, probably related to on changes in the drainage system and/or climate changes. Presence of Podocarpus pollen grains up to 2.6% of the total sum (and influx of 78 grains cm2 yr1) point to regional presence of Podocarpus at the beginning of the Holocene. evidence of Podocarpus during glacial times in other pollen records from the Amazon Basin has been taken as indicative of cooling

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

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    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

  5. Monoterpene Compositions of Three Forested Ecosystems in the Central Amazon Basin

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    Jardine, A.; Fuentes, J. D.; Manzi, A. O.; Higuchi, N.; Chambers, J. Q.; Jardine, K.

    2014-12-01

    Monoterpenes play fundamental roles as secondary metabolites in forested ecosystems and as gas and liquid phase secondary organic aerosol (SOA) precursors in their surrounding atmospheres. While the chemical pathways involved in ozonolysis driven SOA formation from individual monoterpene precursors is known, local and regional chemical transport models are still lacking observations of speciated monoterpenes from forested atmospheres. Here, we present high vertically resolved mixing ratio profiles of speciated monoterpenes from the ambient air of three neighboring forested ecosystems in the central Amazon Basin. Two well-drained plateau primary forests and one seasonally flooded valley forest were sampled during the afternoon hours (13:00 - 16:30) on walkup towers from the initiation of the 2013-14 wet season through the onset of the 2014 dry season (Nov 2013 - Jul 2014). Ambient mixing ratios in all three ecosystems were greatest in the upper canopy with secondary sources of some monoterpenes within the sub-canopies. Relative vertical compositions of monoterpenes did not change significantly throughout the seasons for either ecosystem type. Both ecosystem types were dominated by d-limonene (up to 1.6 ppb) with equally strong mixing ratios of alpha-pinene in the valley compared to the much weaker a-pinene mixing ratios on the plateaus (up to 200 ppt). The highly reactive cis- and trans-beta-ocimene were consistently present in both ecosystems (up to 250 ppt) with the addition of equally high camphene mixing ratios in the valley forest (up to 200 ppt) which is present in the plateau ecosystems in low quantities (50 ppt). With respect to clean atmosphere mixing ratios of 10 ppb ozone, lifetimes are below 2 hours for camphene and below 30 minutes for ocimene, suggesting a potentially large impact on local and possibly regional ozonolysis and subsequent SOA composition.

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

    International Nuclear Information System (INIS)

    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 km2 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−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−2, respectively. • SOC stocks were 34 and 16%, respectively, lower

  7. 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

  8. Modelling conservation in the Amazon basin

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    Soares-Filho, Britaldo Silveira; Nepstad, Daniel Curtis; Curran, Lisa M.; Cerqueira, Gustavo Coutinho; Garcia, Ricardo Alexandrino; Ramos, Claudia Azevedo; Voll, Eliane; McDonald, Alice; Lefebvre, Paul; Schlesinger, Peter

    2006-03-01

    Expansion of the cattle and soy industries in the Amazon basin has increased deforestation rates and will soon push all-weather highways into the region's core. In the face of this growing pressure, a comprehensive conservation strategy for the Amazon basin should protect its watersheds, the full range of species and ecosystem diversity, and the stability of regional climates. Here we report that protected areas in the Amazon basin-the central feature of prevailing conservation approaches-are an important but insufficient component of this strategy, based on policy-sensitive simulations of future deforestation. By 2050, current trends in agricultural expansion will eliminate a total of 40% of Amazon forests, including at least two-thirds of the forest cover of six major watersheds and 12 ecoregions, releasing 32 +/- 8Pg of carbon to the atmosphere. One-quarter of the 382 mammalian species examined will lose more than 40% of the forest within their Amazon ranges. Although an expanded and enforced network of protected areas could avoid as much as one-third of this projected forest loss, conservation on private lands is also essential. Expanding market pressures for sound land management and prevention of forest clearing on lands unsuitable for agriculture are critical ingredients of a strategy for comprehensive conservation.

  9. Impact of seasonal hydrological variation on the distributions of tetraether lipids along the Amazon River in the central Amazon basin: Implications for the MBT/CBT paleothermometer and the BIT index

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    ClaudiaZell

    2013-08-01

    Full Text Available Suspended particulate matter (SPM was collected along the Amazonian rivers in the central Amazon basin and in three tributaries during the rising water (RW, high water (HW, falling water (FW and low water (LW season. Changes in the concentration and the distribution of brGDGTs, i.e. the methylation index of branched tetraethers (MBT and the cyclization of brGDGTs (CBT, were seen in the main stem Amazon. The highest concentration of core lipid branched glycerol dialkyl glycerol tetraethers (brGDGTs normalized to particulate organic carbon was found during the HW season. During the HW season the MBT and CBT in the Amazon main stem was also most similar to that of lowland Amazon (terra firme soils, indicating that the highest input of soil-derived brGDGTs occurs due to increased water runoff. During the other seasons the MBT and CBT indicated an increased influence of in situ production of brGDGTs even though soils remained the main source of brGDGTs. Our results reveal that the influence of seasonal variation is relatively small, but can be clearly detected. Crenarchaeol is mostly produced in the river. Its concentration was lower during the HW season compared to that of the other seasons. Hence, our study shows the complexity of processes that influence the GDGT distribution during the transport from land to ocean. It emphasizes the importance of a detailed study of a river basin to interpret the MBT/CBT and BIT records for paleo reconstructions in adjacent marine setting.

  10. Impact of seasonal hydrological variation on the distributions of branched and isoprenoid tetraether lipids along the Amazon River in the central Amazon basin: Implications for the MBT/CBT paleothermometer and the BIT index

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    Zell, Claudia; Kim, Jung-Hyun; Lima Sobrinho, Rodrigo; Moreira-Turcq, Patricia; Abril Abril, Gwenaël; Sinninghe Damsté, Jaap S.

    2013-04-01

    We assessed the effects of hydrodynamical variations on the distributions and sources of branched and isoprenoid glycerol dialkyl glycerol tetraethers (brGDGTs and isoGDGTs, respectively) transported by the Amazon River in the central Amazon basin. Particulate suspended matter was collected in the Amazonian rivers and floodplain lakes at four different seasons (rising water, high water, falling water, and low water) at 6 stations along the main stem of the Amazon River, 3 tributaries (Negro, Madeira, and Tapajós) and 5 floodplain lakes (Manacapuru, Janauacá, Mirituba, Canaçari and Curuai). The concentration and distribution of brGDGTs of both core lipid (CL) and intact polar lipid (IPL)-derived fractions were investigated applying IPL-derived brGDGTs as an indicator of brGDGTs derived from recently-living cells. The organic carbon (OC)-normalized concentrations of CL brGDGTs mimicked the trend of the hydrological variation with highest concentrations during the high water season. The CL brGDGT distributions were most alike those of lowland Amazon (terra firme) soils during the high water season, indicating that input of soil-derived, allochthonous brGDGTs to the Amazon River was highest at that period. Accordingly, the methylation index of branched tetraethers (MBT) and the cyclization ratio of branched tetraethers (CBT) varied corresponding to the hydrological changes, with the increasing influence of in situ produced brGDGTs in rivers and floodplain lakes during the low water season. The concentrations of CL crenarchaeol were highest during the low water season, due to increased autochthonous production. The concentration changes of both brGDGTs and crenarchaeol lead to a variation of the branched and isoprenoid tetraether (BIT) index between 0.4 (low water) and 0.9 (high water). Hence, our study hints at the effect of hydrodynamical variations on the source of brGDGTs and isoGDGTs transported by rivers to the ocean and emphasized the importance of a detailed

  11. Methane emissions from floodplain trees of the Amazon basin

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    Pangala, Sunitha; Bastviken, David; Enrich-Prast, Alex; Gauci, Vincent

    2016-04-01

    Wetlands are the largest source of methane to the atmosphere, but emission estimates are highly uncertain leading to large discrepancies between emission inventories and much larger estimates of the Amazon methane source derived at larger scales. We examined methane emissions from all emission pathways including aquatic surfaces, emergent soils and herbaceous vegetation and more than 2000 trees from 13 locations across the central Amazon floodplain in 2014. Our data are the first measurements of stem emission from emergent portions of inundated trees in the Amazon and they demonstrate that regionally, tree stems are the dominant means of emissions for soil produced methane to the atmosphere. Emissions via the range of egress pathways varied substantially between sample locations and water-table exerted some control over emissions from ~2m below the soil surface upto 0.5-1m of inundation. Higher water (upto ~10m of inundation) exerted no further control over emissions. Applying our measurements to models of whole tree emission and scaling to the entire Amazon lowland basin demonstrates the significant contribution of trees to regional emissions that can close the Amazon basin methane budget.

  12. Distribution of Aboveground Live Biomass in the Amazon Basin

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    Saatchi, S. S.; Houghton, R. A.; DosSantos Alvala, R. C.; Soares, J. V.; Yu, Y.

    2007-01-01

    The amount and spatial distribution of forest biomass in the Amazon basin is a major source of uncertainty in estimating the flux of carbon released from land-cover and land-use change. Direct measurements of aboveground live biomass (AGLB) are limited to small areas of forest inventory plots and site-specific allometric equations that cannot be readily generalized for the entire basin. Furthermore, there is no spaceborne remote sensing instrument that can measure tropical forest biomass directly. To determine the spatial distribution of forest biomass of the Amazon basin, we report a method based on remote sensing metrics representing various forest structural parameters and environmental variables, and more than 500 plot measurements of forest biomass distributed over the basin. A decision tree approach was used to develop the spatial distribution of AGLB for seven distinct biomass classes of lowland old-growth forests with more than 80% accuracy. AGLB for other vegetation types, such as the woody and herbaceous savanna and secondary forests, was directly estimated with a regression based on satellite data. Results show that AGLB is highest in Central Amazonia and in regions to the east and north, including the Guyanas. Biomass is generally above 300Mgha(sup 1) here except in areas of intense logging or open floodplains. In Western Amazonia, from the lowlands of Peru, Ecuador, and Colombia to the Andean mountains, biomass ranges from 150 to 300Mgha(sup 1). Most transitional and seasonal forests at the southern and northwestern edges of the basin have biomass ranging from 100 to 200Mgha(sup 1). The AGLB distribution has a significant correlation with the length of the dry season. We estimate that the total carbon in forest biomass of the Amazon basin, including the dead and below ground biomass, is 86 PgC with +/- 20% uncertainty.

  13. The impact of Amazonian deforestation on Amazon basin rainfall

    OpenAIRE

    Spracklen, DV; Garcia-Carreras, L.

    2015-01-01

    We completed a meta-analysis of regional and global climate model simulations (n=96) of the impact of Amazonian deforestation on Amazon basin rainfall. Across all simulations, mean (±1σ) change in annual mean Amazon basin rainfall was -12±11%. Variability in simulated rainfall was not explained by differences in model resolution or surface parameters. Across all simulations we find a negative linear relationship between rainfall and deforestation extent, although individual studies often simu...

  14. Forecasting terrestrial water storage changes in the Amazon Basin using Atlantic and Pacific sea surface temperatures

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    C. de Linage

    2013-10-01

    Full Text Available Floods and droughts frequently affect the Amazon River basin, impacting transportation, river navigation, agriculture, and ecosystem processes within several South American countries. Here we examined how sea surface temperatures (SSTs influence interannual variability of terrestrial water storage anomalies (TWSAs in different regions within the Amazon basin and propose a modeling framework for inter-seasonal flood and drought forecasting. Three simple statistical models forced by a linear combination of lagged spatial averages of central Pacific (Niño 4 index and tropical North Atlantic (TNAI index SSTs were calibrated against a decade-long record of 3°, monthly TWSAs observed by the Gravity Recovery And Climate Experiment (GRACE satellite mission. Niño 4 was the primary external forcing in the northeastern region of the Amazon basin whereas TNAI was dominant in central and western regions. A combined model using the two indices improved the fit significantly (p < 0.05 for at least 64% of the grid cells within the basin, compared to models forced solely with Niño 4 or TNAI. The combined model explained 66% of the observed variance in the northeastern region, 39% in the central and western regions, and 43% for the Amazon basin as a whole with a 3 month lead time between the SST indices and TWSAs. Model performance varied seasonally: it was higher than average during the rainfall wet season in the northeastern Amazon and during the dry season in the central and western regions. The predictive capability of the combined model was degraded with increasing lead times. Degradation was smaller in the northeastern Amazon (where 49% of the variance was explained using an 8 month lead time vs. 69% for a 1 month lead time compared to the central and western Amazon (where 22% of the variance was explained at 8 months vs. 43% at 1 month. These relationships may enable the development of an early warning system for flood and drought risk. This work also

  15. The Late Miocene paleogeography of the Amazon Basin and the evolution of the Amazon River system

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    Latrubesse, Edgardo M.; Cozzuol, Mario; da Silva-Caminha, Silane A. F.; Rigsby, Catherine A.; Absy, Maria Lucia; Jaramillo, Carlos

    2010-05-01

    On the basis of paleontological content (vertebrates and palynology) and facies analysis from river banks, road cuts, and three wells, we have assigned the uppermost levels of the Solimões Formation in western Amazonia, Brazil, to the Late Miocene. The vertebrate fossil record from outcropping sediments is assigned to the Huayquerian-Mesopotamian mammalian biozones, spanning 9-6.5 Ma. Additionally, we present results that demonstrate that deposits in Peruvian Amazonia attributed to Miocene tidal environments are actually fluvial sediments that have been misinterpreted (both environmentally and chronologically) by several authors. The entire Late Miocene sequence was deposited in a continental environment within a subsiding basin. The facies analysis, fossil fauna content, and palynological record indicate that the environment of deposition was dominated by avulsive rivers associated with megafan systems, and avulsive rivers in flood basins (swamps, lakes, internal deltas, and splays). Soils developed on the flatter, drier areas, which were dominated by grasslands and gallery forest in a tropical to subtropical climate. These Late Miocene sediments were deposited from westward of the Purus arch up to the border of Brazil with Peru (Divisor Ranges) and Bolivia (Pando block). Eastward of the Iquitos structural high, however, more detailed studies, including vertebrate paleontology, need to be performed to calibrate with more precision the ages of the uppermost levels of the Solimões Formation. The evolution of the basin during the late Miocene is mainly related to the tectonic behavior of the Central Andes (˜ 3°-15°S). At approximately 5 Ma, a segment of low angle of subduction was well developed in the Nazca Plate, and the deformation in the Subandean foreland produced the inland reactivation of the Divisor/Contamana Ranges and tectonic arrangements in the Eastern Andes. During the Pliocene southwestern Brazilian Amazonia ceased to be an effective sedimentary

  16. The impact of Amazonian deforestation on Amazon basin rainfall

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    Spracklen, D. V.; Garcia-Carreras, L.

    2015-11-01

    We completed a meta-analysis of regional and global climate model simulations (n = 96) of the impact of Amazonian deforestation on Amazon basin rainfall. Across all simulations, mean (±1σ) change in annual mean Amazon basin rainfall was -12 ± 11%. Variability in simulated rainfall was not explained by differences in model resolution or surface parameters. Across all simulations we find a negative linear relationship between rainfall and deforestation extent, although individual studies often simulate a nonlinear response. Using the linear relationship, we estimate that deforestation in 2010 has reduced annual mean rainfall across the Amazon basin by 1.8 ± 0.3%, less than the interannual variability in observed rainfall. This may explain why a reduction in Amazon rainfall has not consistently been observed. We estimate that business-as-usual deforestation (based on deforestation rates prior to 2004) would lead to an 8.1 ± 1.4% reduction in annual mean Amazon basin rainfall by 2050, greater than natural variability.

  17. Biophysical stratification of the Amazon basin

    International Nuclear Information System (INIS)

    In field measurement programmes, stratified sampling can optimize sampling efficiency, but stratification is often undertaken subjectively, and is frequently based on a priori classification schemes such as those used for vegetation maps. In order to avoid the problems associated with a priori subjective schemes, we explore here an objective procedure, Regression Tree Analysis (RTA). RTA has previously been used in local-scale studies, but here we apply it to a very large study domain, namely the entire humid tropical zone of South America. The aim of the study was to develop an optimal sampling design in preparation for the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA). Co-registered spatially continuous fields of rainfall, temperature, photosynthetically active radiation (PAR), the normalized difference index (NDVI), an index of surface moisture, and other independent variables were used to predict three dependent variables, annual net radiation (Rn), latent heat (LE) and net primary production (NPP). Rather than simply dividing the study area based on differing levels of the three dependent variables, empirical models were developed using RTA to indicate how the relationships between these and possible forcing variables vary across the study area. For each variable long-term seasonal indices such as annual average, monthly minimum and amplitude were used to exclude effects of temporal phase differences between the hemispheres. The resulting hierarchical models revealed variations in the interdependence of the forcing variables throughout the study area and therefore provided a basis for a stratified sampling and identifying the most important variables to be collected in LBA for the Amazon basin as a whole as well as optimizing the sampling scheme for scaling up findings from the field scale to larger areas. (author)

  18. Regional nitrous oxide flux in Amazon basin

    International Nuclear Information System (INIS)

    Nitrous oxide (N2O) is the third most important anthropogenic greenhouse gas. Globally, the main sources of N2O 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 N2O 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 N2O fluxes for regions upwind of these sites using two methods: Column Integration Technique and Inversion Model - FLEXPART. To our knowledge, these regional scale N2O 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 mgN2Om-2day-1 for the Column Integration Technique and 2.3±0.9 mgN2Om-2day-1 for Inversion Model - FLEXPART. For fluxes upwind of Tapajos Nacional Forest, the Inversion Model - FLEXPART presented about half (0.9±1.7 mgN2Om-2day-1) of the Column Integration Technique (2.0±1.1 mgN2Om-2day-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 N2O fluxes exhibit significant correlations with CO fluxes, indicating a larger than expected source of N2O from biomass burning. The average CO:N2O ratio for all 38 profiles sampled during the dry season was 82±69 mol CO:molN2O and suggests a larger biomass burning contribution to the global N2O budget than previously reported. (author)

  19. Modelling basin-wide variations in Amazon forest photosynthesis

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    Mercado, Lina; Lloyd, Jon; Domingues, Tomas; Fyllas, Nikolaos; Patino, Sandra; Dolman, Han; Sitch, Stephen

    2010-05-01

    Given the importance of Amazon rainforest in the global carbon and hydrological cycles, there is a need to use parameterized and validated ecosystem gas exchange and vegetation models for this region in order to adequately simulate present and future carbon and water balances. Recent research has found major differences in above-ground net primary productivity (ANPP), above ground biomass and tree dynamics across Amazonia. West Amazonia is more dynamic, with younger trees, higher stem growth rates and lower biomass than central and eastern Amazon (Baker et al. 2004; Malhi et al. 2004; Phillips et al. 2004). A factor of three variation in above-ground net primary productivity has been estimated across Amazonia by Malhi et al. (2004). Different hypotheses have been proposed to explain the observed spatial variability in ANPP (Malhi et al. 2004). First, due to the proximity to the Andes, sites from western Amazonia tend to have richer soils than central and eastern Amazon and therefore soil fertility could possibly be highly related to the high wood productivity found in western sites. Second, if GPP does not vary across the Amazon basin then different patterns of carbon allocation to respiration could also explain the observed ANPP gradient. However since plant growth depends on the interaction between photosynthesis, transport of assimilates, plant respiration, water relations and mineral nutrition, variations in plant gross photosynthesis (GPP) could also explain the observed variations in ANPP. In this study we investigate whether Amazon GPP can explain variations of observed ANPP. We use a sun and shade canopy gas exchange model that has been calibrated and evaluated at five rainforest sites (Mercado et al. 2009) to simulate gross primary productivity of 50 sites across the Amazon basin during the period 1980-2001. Such simulation differs from the ones performed with global vegetation models (Cox et al. 1998; Sitch et al. 2003) where i) single plant functional

  20. Spectrometry of pasture condition and biogeochemistry in the central Amazon

    Science.gov (United States)

    Asner, Gregory P.; Townsend, Alan R.; Bustamante, Mercedes M. C.

    Regional analyses of Amazon cattle pasture biogeochemistry are difficult due to the complexity of human, edaphic, biotic and climatic factors and persistent cloud cover in satellite observations. We developed a method to estimate key biophysical properties of Amazon pastures using hyperspectral reflectance data and photon transport inverse modeling. Remote estimates of live and senescent biomass were strongly correlated with plant-available forms of soil phosphorus and calcium. These results provide a basis for monitoring pasture condition and biogeochemistry in the Amazon Basin using spaceborne hyperspectral sensors.

  1. Spectrometry of Pasture Condition and Biogeochemistry in the Central Amazon

    Science.gov (United States)

    Asner, Gregory P.; Townsend, Alan R.; Bustamante, Mercedes M. C.

    1999-01-01

    Regional analyses of Amazon cattle pasture biogeochemistry are difficult due to the complexity of human, edaphic, biotic and climatic factors and persistent cloud cover in satellite observations. We developed a method to estimate key biophysical properties of Amazon pastures using hyperspectral reflectance data and photon transport inverse modeling. Remote estimates of live and senescent biomass were strongly correlated with plant-available forms of soil phosphorus and calcium. These results provide a basis for monitoring pasture condition and biogeochemistry in the Amazon Basin using spaceborne hyperspectral sensors.

  2. 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 to...

  3. Links between Climate, Malaria, and Wetlands in the Amazon Basin

    OpenAIRE

    Olson, Sarah H.; Gangnon, Ronald; Elguero, Eric; Durieux, Laurent; Guégan, Jean-François; Foley, Jonathan A.; Patz, Jonathan A.

    2009-01-01

    Climate changes are altering patterns of temperature and precipitation, potentially affecting regions of malaria transmission. We show that areas of the Amazon Basin with few wetlands show a variable relationship between precipitation and malaria, while areas with extensive wetlands show a negative relationship with malaria incidence.

  4. Large-scale Modeling of Inundation in the Amazon Basin

    Science.gov (United States)

    Luo, X.; Li, H. Y.; Getirana, A.; Leung, L. R.; Tesfa, T. K.

    2015-12-01

    Flood events have impacts on the exchange of energy, water and trace gases between land and atmosphere, hence potentially affecting the climate. The Amazon River basin is the world's largest river basin. Seasonal floods occur in the Amazon Basin each year. The basin being characterized by flat gradients, backwater effects are evident in the river dynamics. This factor, together with large uncertainties in river hydraulic geometry, surface topography and other datasets, contribute to difficulties in simulating flooding processes over this basin. We have developed a large-scale inundation scheme in the framework of the Model for Scale Adaptive River Transport (MOSART) river routing model. Both the kinematic wave and the diffusion wave routing methods are implemented in the model. A new process-based algorithm is designed to represent river channel - floodplain interactions. Uncertainties in the input datasets are partly addressed through model calibration. We will present the comparison of simulated results against satellite and in situ observations and analysis to understand factors that influence inundation processes in the Amazon Basin.

  5. Basin-Wide Amazon Forest Tree Mortality From a Large 2005 Storm

    Science.gov (United States)

    Negron Juarez, R. I.; Chambers, J. Q.; Guimaraes, G.; Zeng, H.; Raupp, C.; Marra, D. M.; Ribeiro, G.; Saatchi, S. S.; Higuchi, N.

    2010-12-01

    Blowdowns are a recurrent characteristic of Amazon forests and are produced, among others, by squall lines. Squall lines are aligned clusters (typical length of 1000 km, width of 200 km) of deep convective cells that produce heavy rainfall during the dry season and significant rainfall during the wet season. These squall lines (accompanied by intense downbursts from convective cells) have been associated with large blowdowns characterized by uprooted, snapped trees, and trees being dragged down by other falling trees. Most squall lines in Amazonia form along the northeastern coast of South America as sea breeze-induced instability lines and propagate inside the continent. They occur frequently (~4 times per month), and can reach the central and even extreme western parts of Amazonia. Squall lines can also be generated inside the Amazon and propagate toward the equator. In January 2005 a squall line propagated from south to north across the entire Amazon basin producing widespread forest tree mortality and contributed to the elevated mortality observed that year. Over the Manaus region (3.4 x104 km2), disturbed forest patches generated by the squall produced a mortality of 0.3-0.5 million trees, equivalent to 30% of the observed annual deforestation reported in 2005 over the same area. The elevated mortality observed in the Central Amazon in 2005 is unlikely to be related to the 2005 Amazon drought since drought did not affect Central or Eastern Amazonia. Assuming a similar rate of forest mortality across the basin, the squall line could have potentially produced tree mortality estimated at 542 ± 121 million trees, equivalent to 23% of the mean annual biomass accumulation estimated for these forests. Our results highlight the vulnerability of Amazon trees to wind-driven mortality associated with convective storms. This vulnerability is likely to increase in a warming climate with models projecting an increase in storm intensity.

  6. Influence Deforestation on Hydrological Cycle at Amazon Basin

    Science.gov (United States)

    Cohen, J. C.; Beltrao, J.; Gandu, A. W.

    2007-05-01

    The last three decades, the Amazon Basin has been affected for the occupation with consequence large deforestation. The principal area deforested is located from Maranhao state to Rondonia state. This area is common called "Arc Deforestation", and representing the transition between two important Brazilian ecosystems, Amazon Forest and Savanna Region. Theses ecosystems have precious biodiversity, and it has population about 10.331.000. The objective of this work was to evaluate the impact of arc deforestation on the hydrological cycle at Amazon basin, using BRAMS (Brazilian developments on the Regional Atmospheric Modeling System) including a model of dynamic vegetation, called GEMTM (General Energy and Mass Transport Model). In this study, numerical simulations were performed with a high spatial resolution regional model that allows capture some mesoscale aspects associated to the land used, topography, coastlines and large rivers. In order to predict the impact of the arc deforestation over the hydrological cycle, it was run two model simulations, conducted over a one-year period. In the first simulation, designated "control", it was used the scenarios derived from Soares Filho (2002), for the year 2002, in governance situation. In the second simulation called "deforestation", it was used the scenarios for the 2050, derived from results of Soares-Filho with governance, too. The higher-resolution regional modeling revealed important features of the deforestation process, displaying some associated mesoscale effects that are not typically represented in similar Global Circulation Model simulations. Near coastal zones and along large rivers, deforestation resulted in reduced precipitation. However, it was predicted increased precipitation over mountainous areas, especially on mountain slopes facing river valleys. Then, these higher-resolution simulations showed that, in general, orography, coastline profile and large river distribution play important roles in

  7. Estimation of the evapotranspiration in the Amazon Basin

    International Nuclear Information System (INIS)

    The establishment of a water balance for the Amazon Basin constitutes a problem of difficult solution, not only on the account of its extension and characteristics, but also for lack of sufficient meteorological and hydrological data. In an attempt to estimate the magnitude of the main components of the water balance, a study was made with data from the Brazilian Amazon Region and from some observation stations in other countries. An energy balance was made and based on this balance the water balance of the region was established, having the Penman method been adapted to forest conditions. The data obtained indicate that 90% of the evaportranspiration is due to the energy balance. The evaportranspiration in this area should be very close to the potential evaportranspiration, and the average found was of the order of 4mm/day, i.e., 1460mm/year. As a first approximation it was found that the Amazon Basin system receives 14,4X1012m3 water/year through precipitation, this total being balanced by a surface discharge of 5,5 x1012m3 /year and an evaportranspiration of 8,9x1012m3/year. Since transpiration by plants represents 61,8% of the water balance, all seems to indicate that intensive deforestation shall bring about alterations of the hydrological cycle

  8. Rickettsial Disease in the Peruvian Amazon Basin

    Science.gov (United States)

    Kocher, Claudine; Morrison, Amy C.; Leguia, Mariana; Loyola, Steev; Castillo, Roger M.; Galvez, Hugo A.; Astete, Helvio; Flores-Mendoza, Carmen; Ampuero, Julia S.; Bausch, Daniel G.; Halsey, Eric S.; Cespedes, Manuel; Zevallos, Karine; Jiang, Ju; Richards, Allen L.

    2016-01-01

    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. PMID:27416029

  9. Tectonic control of erosion and sedimentation in the Amazon Basin of Bolivia

    OpenAIRE

    Baby, Patrice; Guyot, Jean-Loup; Hérail, Gérard

    2009-01-01

    The western Amazon drainage basin, which extends from southern Colombia to northern Bolivia, comprises the Cordillera Oriental of the Andes and its adjacent Foreland basin system. In northern Bolivia, the orogenic wedge of the eastern Andes is very large, and its forward propagation controls the morphology of the Madeira drainage basin. We consider here the erosion and sedimentation mass balance in this part of the Amazon Basin, estimated on the basis of recent sediment yield data, within the...

  10. Deforestation, floodplain dynamics, and carbon biogeochemistry in the Amazon Basin

    Science.gov (United States)

    Bryan, M. L.; Dunne, T.; Richey, J.; Melack, J.; Simonett, D. S.; Woodwell, G.

    1984-01-01

    Three aspects of the physical geographic environment of the Amazon Basin are considered: (1) deforestation and reforestation, (2) floodplain dynamics, and (3) fluvial geomorphology. Three independent projects are coupled in this experiment to improve the in-place research and to ensure that the Shuttle Imaging Radar-B (SIR-B) experiment stands on a secure base of ongoing work. Major benefits to be obtained center on: (1) areal and locational information, (2) data from various depression angles, and (3) digital radar signatures. Analysis will be conducted for selected sites to define how well SIR-B data can be used for: (1) definition of extent and location of deforestation in a tropical moist forest, (2) definition and quantification of the nature of the vegetation and edaphic conditions on the (floodplain) of the Amazon River, and (3) quantification of the accuracy with which the geometry and channel shifting of the Amazon River may be mapped using SIR-B imagery in conjunction with other remote sensing data.

  11. Artisanal fisheries of the Xingu River basin in Brazilian Amazon.

    Science.gov (United States)

    Isaac, V J; Almeida, M C; Cruz, R E A; Nunes, L G

    2015-08-01

    The present study characterises the commercial fisheries of the basin of the Xingu River, a major tributary of the Amazon River, between the towns of Gurupá (at the mouth of the Amazon) and São Félix do Xingu. Between April, 2012, and March, 2014, a total of 23,939 fishing trips were recorded, yielding a total production of 1,484 tons of fish, harvested by almost three thousand fishers. The analysis of the catches emphasizes the small-scale and artisanal nature of the region's fisheries, with emphasis on the contribution of the motorised canoes powered by "long-tail" outboard motors. Larger motorboats operate only at the mouth of the Xingu and on the Amazon. Peacock bass (Cichla spp.), croakers (Plagioscion spp.), pacu (a group containing numerous serrasalmid species), aracu (various anostomids), and curimatã (Prochilodus nigricans) together contributed more than 60% of the total catch. Mean catch per unit effort was 18 kg/fisher-1.day-1, which varied among fishing methods (type of vessel and fishing equipment used), river sections, and time of the year. In most cases, yields varied little between years (2012 and 2013). The technical database provided by this study constitutes an important resource for the regulation of the region's fisheries, as well as for the evaluation of future changes resulting from the construction of the Belo Monte dam on the Xingu River. PMID:26691085

  12. Runoff modeling of the Amazon basin using 18 O as a conservative tracer

    International Nuclear Information System (INIS)

    Using the δO18 O content of natural waters as a conservative tracer, a runoff modelling of the Amazon river basin was carried out in order to study the hydrological characteristics of the precipitation-runoff relationship. Measurements of the δ18 O in rainfall waters made in the high Solimoes region at Benjamin Constant, in the central part of basin at Manaus, and at the mouth near the Marajo Island, while the river waters were measured at Obidos only, as a proxy for the mouth, during the 1973-1974 hydrological years. The hydrography separation of the Amazon river was performed using the isotopic method to estimate the contributions of the surface runoff (event water) and baseflow (pre-event water) components to the total river flow. At peak discharge, the average contribution of the baseflow was 57% of the total river flow. The annual average contributions for surface runoff and baseflow were 30.3 and 69.7%, respectively. The residence time of the subsurface water in the basin was estimated as being 7 months, by fitting a sinusoidal function to the isotopic values of rainfall and river waters. The low values of the amplitude damping in the basin suggest high mixing waters during the runoff process. (author). 21 refs., 4 figs., 1 tab

  13. Nuclear method applied in archaeological sites at the Amazon basin

    International Nuclear Information System (INIS)

    The aim of this work was to use the nuclear methodology to character pottery discovered 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. The sites are located mainly in the Hydrographic Basin of High Purus River. Three of them were strategic chosen to collect 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. Neutron Activation Analysis in conjunction with multivariate statistical methods were used for the ceramic characterization and classification. An homogeneous group was established by all the sherds collected from Alto Alegre and was distinct from the other two groups analyzed. Some of the sherds collected from Xipamunu I appeared in Lobao's urns, probably because they had the same fabrication process. (author)

  14. Transfer of trace elements in the Amazon basin

    International Nuclear Information System (INIS)

    The Amazon basin is the world's largest system both in terms of drainage area, 7x106 km2, and sediment discharge, about 1.3x109 tons of solid suspended material each year. It is located at northern South America in the equatorial zone, extending through nine countries, Bolivia, Peru, Ecuador, Colombia, Venezuela, Surinam, French Guyana, and Brazil, where is the majority (70%) of the total area. The Amazon basin is geologically limited in the west by the Andes Cordillera, in the south by the Brazilian altiplain, in the north by the Guyana mountains and in the east by the Atlantic Ocean. It is the most fabulous natural ecosystem of the world, remaining in a perfect state of equilibrium, not yet deeply studied. The development of mathematic models describing its dynamics is very important for its comprehension and preservation. Trace elements, in special the rare earth elements, can be useful to elaborate such models. Several processes in rivers and estuaries have been investigated through the use of REEs as tracers, addressing the riverine input of elements to the oceans from continents. Trace elements were also used to elaborate a model for chemical exchange from the water to the sediments and the subsequent release from the sediments into the water. (5 refs., 6 figs.)

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

    Science.gov (United States)

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

    2016-04-01

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

  16. Sources of carbonaceous aerosol in the Amazon basin

    Directory of Open Access Journals (Sweden)

    S. Gilardoni

    2011-03-01

    Full Text Available The quantification of sources of carbonaceous aerosol is important to understand their atmospheric concentrations and regulating processes and to study possible effects on climate and air quality, in addition to develop mitigation strategies.

    In the framework of the European Integrated Project on Aerosol Cloud Climate Interactions (EUCAARI fine (Dp < 2.5 μm and coarse (2.5 μm < Dp <10 μm aerosol particles were sampled from February to June (wet season and from August to September (dry season 2008 in the central Amazon basin. The mass of fine particles averaged 2.4 μg m−3 during the wet season and 4.2 μg m−3 during the dry season. The average coarse aerosol mass concentration during wet and dry periods was 7.9 and 7.6 μg m−3, respectively. The overall chemical composition of fine and coarse mass did not show any seasonality with the largest fraction of fine and coarse aerosol mass explained by organic carbon (OC; the average OC to mass ratio was 0.4 and 0.6 in fine and coarse aerosol modes, respectively. The mass absorbing cross section of soot was determined by comparison of elemental carbon and light absorption coefficient measurements and it was equal to 4.7 m2 g−1 at 637 nm. Carbon aerosol sources were identified by Positive Matrix Factorization (PMF analysis of thermograms: 44% of fine total carbon mass was assigned to biomass burning, 43% to secondary organic aerosol (SOA, and 13% to volatile species that are difficult to apportion. In the coarse mode, primary biogenic aerosol particles (PBAP dominated the carbonaceous aerosol mass. The results confirmed the importance of PBAP in forested areas.

    The source apportionment results were employed to evaluate the ability of global chemistry transport models to simulate carbonaceous aerosol sources in a regional tropical background site. The comparison showed an overestimation

  17. Sensitivity of Regional Climate to Deforestation in the Amazon Basin

    Science.gov (United States)

    Eltahir, Elfatih A. B.; Bras, Rafael L.

    1994-01-01

    The deforestation results in several adverse effect on the natural environment. The focus of this paper is on the effects of deforestation on land-surface processes and regional climate of the Amazon basin. In general, the effect of deforestation on climate are likely to depend on the scale of the defrosted area. In this study, we are interested in the effects due to deforestation of areas with a scale of about 250 km. Hence, a meso-scale climate model is used in performing numerical experiments on the sensitivity of regional climate to deforestation of areas with that size. It is found that deforestation results in less net surface radiation, less evaporation, less rainfall, and warmer surface temperature. The magnitude of the of the change in temperature is of the order 0.5 C, the magnitudes of the changes in the other variables are of the order of IO%. In order to verify some of he results of the numerical experiments, the model simulations of net surface radiation are compared to recent observations of net radiation over cleared and undisturbed forest in the Amazon. The results of the model and the observations agree in the following conclusion: the difference in net surface radiation between cleared and undisturbed forest is, almost, equally partioned between net solar radiation and net long-wave radiation. This finding contributes to our understanding of the basic physics in the deforestation problem.

  18. Structural aspects of the atmospheric aerosol of the Amazon basin

    International Nuclear Information System (INIS)

    The results presented on this paper may be considered as complementary to the ones published on two previous papers about the natural atmospheric aerosol of the Amazon Basin, and the effects, on these physical-chemical systems of the large scale brushfires carried out from time to time on that region. The experiments have been performed in August-September, 1980, simultaneously to the ones of the 'Projeto Queimadas - 1980' promoted by the National Center for Atmospheric Research from the U.S.A.. The new results here in presented are size distribution concentration data as log-probability curves for the detected tracer-elements; from these curves, by introducing a new technique, is was possible to derive the corresponding log-normal curves. These last curves can be used conveniently to characterize the atmospheric aerosol system which is under investigation. (Author)

  19. Iron cycling in the Amazon River Basin: the isotopic perspective

    Science.gov (United States)

    Poitrasson, Franck; Vieira, Lucieth; Mulholland, Daniel; Seyler, Patrick; Sondag, Francis; Allard, Thierry

    2014-05-01

    With the global climate change and increasing anthropic pressure on nature, it is important to find new indicators of the response of complex systems like the Amazon River Basin. In particular, new tracers like iron isotopes may tell us much on processes such as the chemical exchanges between rivers, soils and the biosphere. Pioneering studies revealed that for some river waters, large δ57Fe fractionations are observed between the suspended and dissolved load (Bergquist and Boyle, 2006), and isotopic variations were also recognized on the suspended matter along the hydrological cycle (Ingri et al., 2006). On land, soil studies from various locations have shown that δ57Fe signatures depend mostly on the weathering regime (Fantle and DePaolo, 2004; Emmanuel et al., 2005; Wiederhold et al., 2007; Poitrasson et al., 2008). It thus seems that Fe isotopes could become an interesting new tracer of the exchanges between soils, rivers and the biosphere. We therefore conducted Fe isotope surveys through multidisciplinary field missions on rivers from the Amazon Basin. It was confirmed that acidic, organic-rich black waters show strong Fe isotope fractionation between particulate and dissolved loads. Furthermore, this isotopic fractionation varies along the hydrological cycle, like previously uncovered in boreal waters suspended matter. In contrast, unfiltered waters show very little variation with time. It was also found that Fe isotopes remain a conservative tracer even in the case of massive iron loss during the mixing of chemically contrasted waters such as the Negro and Solimões tributaries of the Amazon River. Given that >95% of the Fe from the Amazon River is carried as detrital materials, our results lead to the conclusion that the Fe isotope signature delivered to the Atlantic Ocean is undistinguishable from the continental crust value, in contrast to previous inferences. The results indicate that Fe isotopes in rivers represent a promising indicator of the

  20. The Amazon. Bio-geochemistry applied to river basin management

    International Nuclear Information System (INIS)

    A hydrochemical model, using hydrograph separation, developed for the Niger basin, has been proposed as a strategic tool for studying the watershed dynamics at any time and space scales. The model is applied to the Amazon basin, including the main channel and its major tributaries. The database corresponds to a sampling and analytical program developed over 8 cruises at 9 stations (about 70 samples), collected in the framework of the CAMREX Project (1982-1984). The model, based on a hydrograph separation of 3 reservoirs, is successful in extrapolating and predicting the geochemical and environmental behaviour of such large basins, naturally submitted to large secular or annual, regular or even catastrophic climatic oscillations. Several topics have been considered. (1) Coherence among the physico-chemical analyses: dissolved species (pH, NH4+, Na+, K+, Ca2+, Mg2+, NO3-, HCO3-, Cl-, DOC-, SO42-, HPO42-, SiO2, O2 and CO2), and inorganic or organic suspended load (fine and coarse fractions FSS, CSS, POCF, POCC). (2) Hydrograph separation in 3 reservoir contributions: RS, the superficial or rapid runoff, RI, the hypodermic or intermediate runoff, including the flood plain contributions, and RB the ground water or base flow. (3) Estimation of the isotopic and physico-chemical features of each of the 3 flow components: RS, RI, and RB. (4) Determination of the 3 hydrological parameters (size of the reservoir, drying up coefficient, and residence time of water), characterizing each of the 3 flow components (RS, RI, and RB), in each of the 9 basins considered. (5) Hydrological and geochemical balances for all the parameters analysed either (a) cruise by cruise for all tributaries and the Amazon River at Obidos, or (b) among each of the 3 river flow components. (6) Isotopic data set of δ18O in waters, tests of coherence of the hydrograph separation model. (7) Relationships between isotopic signatures and morphological or hydroclimatical parameters characterizing the river

  1. Amazon Basin climate under global warming: the role of the sea surface temperature

    OpenAIRE

    Harris, Phil P.; Huntingford, Chris; Cox, Peter M

    2008-01-01

    The Hadley Centre coupled climate–carbon cycle model (HadCM3LC) predicts loss of the Amazon rainforest in response to future anthropogenic greenhouse gas emissions. In this study, the atmospheric component of HadCM3LC is used to assess the role of simulated changes in mid-twenty-first century sea surface temperature (SST) in Amazon Basin climate change. When the full HadCM3LC SST anomalies (SSTAs) are used, the atmosphere model reproduces the Amazon Basin climate change exhibited by HadCM3LC,...

  2. Chemodiversity of dissolved organic matter in the Amazon Basin

    Science.gov (United States)

    Gonsior, Michael; Valle, Juliana; Schmitt-Kopplin, Philippe; Hertkorn, Norbert; Bastviken, David; Luek, Jenna; Harir, Mourad; Bastos, Wanderley; Enrich-Prast, Alex

    2016-07-01

    Regions in the Amazon Basin have been associated with specific biogeochemical processes, but a detailed chemical classification of the abundant and ubiquitous dissolved organic matter (DOM), beyond specific indicator compounds and bulk measurements, has not yet been established. We sampled water from different locations in the Negro, Madeira/Jamari and Tapajós River areas to characterize the molecular DOM composition and distribution. Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) combined with excitation emission matrix (EEM) fluorescence spectroscopy and parallel factor analysis (PARAFAC) revealed a large proportion of ubiquitous DOM but also unique area-specific molecular signatures. Unique to the DOM of the Rio Negro area was the large abundance of high molecular weight, diverse hydrogen-deficient and highly oxidized molecular ions deviating from known lignin or tannin compositions, indicating substantial oxidative processing of these ultimately plant-derived polyphenols indicative of these black waters. In contrast, unique signatures in the Madeira/Jamari area were defined by presumably labile sulfur- and nitrogen-containing molecules in this white water river system. Waters from the Tapajós main stem did not show any substantial unique molecular signatures relative to those present in the Rio Madeira and Rio Negro, which implied a lower organic molecular complexity in this clear water tributary, even after mixing with the main stem of the Amazon River. Beside ubiquitous DOM at average H / C and O / C elemental ratios, a distinct and significant unique DOM pool prevailed in the black, white and clear water areas that were also highly correlated with EEM-PARAFAC components and define the frameworks for primary production and other aspects of aquatic life.

  3. Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest

    Directory of Open Access Journals (Sweden)

    Kolby J. Jardine

    2015-09-01

    Full Text Available Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C5 and C6 GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C6 GLVs were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress.

  4. Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest.

    Science.gov (United States)

    Jardine, Kolby J; Chambers, Jeffrey Q; Holm, Jennifer; Jardine, Angela B; Fontes, Clarissa G; Zorzanelli, Raquel F; Meyers, Kimberly T; de Souza, Vinicius Fernadez; Garcia, Sabrina; Gimenez, Bruno O; Piva, Luani R de O; Higuchi, Niro; Artaxo, Paulo; Martin, Scot; Manzi, Antônio O

    2015-01-01

    Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV) emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C₅ and C₆ GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C₆ GLVs) were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress. PMID:27135346

  5. Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest

    Science.gov (United States)

    Jardine, Kolby J.; Chambers, Jeffrey Q.; Holm, Jennifer; Jardine, Angela B.; Fontes, Clarissa G.; Zorzanelli, Raquel F.; Meyers, Kimberly T.; de Souza, Vinicius Fernadez; Garcia, Sabrina; Gimenez, Bruno O.; de O. Piva, Luani R.; Higuchi, Niro; Artaxo, Paulo; Martin, Scot; Manzi, Antônio O.

    2015-01-01

    Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV) emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C5 and C6 GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C6 GLVs) were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress.

  6. The Amazon Tall Tower Observatory (ATTO in the remote Amazon Basin: overview of first results from ecosystem ecology, meteorology, trace gas, and aerosol measurements

    Directory of Open Access Journals (Sweden)

    M. O. Andreae

    2015-04-01

    Full Text Available The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It already has been changed significantly by human activities, and more pervasive change is expected to occur in the next decades. It is therefore essential to establish long-term measurement sites that provide a baseline record of present-day climatic, biogeochemical, and atmospheric conditions and that will be operated over coming decades to monitor change in the Amazon region as human perturbations increase in the future. The Amazon Tall Tower Observatory (ATTO has been set up in a pristine rain forest region in the central Amazon Basin, about 150 km northeast of the city of Manaus. An ecological survey including a biodiversity assessment has been conducted in the forest region surrounding the site. Two 80 m towers have been operated at the site since 2012, and a 325 m tower is nearing completion in mid-2015. Measurements of micrometeorological and atmospheric chemical variables were initiated in 2012, and their range has continued to broaden over the last few years. The meteorological and micrometeorological measurements include temperature and wind profiles, precipitation, water and energy fluxes, turbulence components, soil temperature profiles and soil heat fluxes, radiation fluxes, and visibility. A tree has been instrumented to measure stem profiles of temperature, light intensity, and water content in cryptogamic covers. The trace gas measurements comprise continuous monitoring of carbon dioxide, carbon monoxide, methane, and ozone at 5 to 8 different heights, complemented by a variety of additional species measured during intensive campaigns (e.g., VOC, NO, NO2, and OH reactivity. Aerosol optical, microphysical, and chemical measurements are made above the canopy as well as in the canopy space. They include light scattering and absorption, aerosol fluorescence, number and volume size distributions, chemical

  7. The Amazon Tall Tower Observatory (ATTO) in the remote Amazon Basin: overview of first results from ecosystem ecology, meteorology, trace gas, and aerosol measurements

    Science.gov (United States)

    Andreae, M. O.; Acevedo, O. C.; Araùjo, A.; Artaxo, P.; Barbosa, C. G. G.; Barbosa, H. M. J.; Brito, J.; Carbone, S.; Chi, X.; Cintra, B. B. L.; da Silva, N. F.; Dias, N. L.; Dias-Júnior, C. Q.; Ditas, F.; Ditz, R.; Godoi, A. F. L.; Godoi, R. H. M.; Heimann, M.; Hoffmann, T.; Kesselmeier, J.; Könemann, T.; Krüger, M. L.; Lavric, J. V.; Manzi, A. O.; Moran-Zuloaga, D.; Nölscher, A. C.; Santos Nogueira, D.; Piedade, M. T. F.; Pöhlker, C.; Pöschl, U.; Rizzo, L. V.; Ro, C.-U.; Ruckteschler, N.; Sá, L. D. A.; Sá, M. D. O.; Sales, C. B.; Santos, R. M. N. D.; Saturno, J.; Schöngart, J.; Sörgel, M.; de Souza, C. M.; de Souza, R. A. F.; Su, H.; Targhetta, N.; Tóta, J.; Trebs, I.; Trumbore, S.; van Eijck, A.; Walter, D.; Wang, Z.; Weber, B.; Williams, J.; Winderlich, J.; Wittmann, F.; Wolff, S.; Yáñez-Serrano, A. M.

    2015-04-01

    The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It already has been changed significantly by human activities, and more pervasive change is expected to occur in the next decades. It is therefore essential to establish long-term measurement sites that provide a baseline record of present-day climatic, biogeochemical, and atmospheric conditions and that will be operated over coming decades to monitor change in the Amazon region as human perturbations increase in the future. The Amazon Tall Tower Observatory (ATTO) has been set up in a pristine rain forest region in the central Amazon Basin, about 150 km northeast of the city of Manaus. An ecological survey including a biodiversity assessment has been conducted in the forest region surrounding the site. Two 80 m towers have been operated at the site since 2012, and a 325 m tower is nearing completion in mid-2015. Measurements of micrometeorological and atmospheric chemical variables were initiated in 2012, and their range has continued to broaden over the last few years. The meteorological and micrometeorological measurements include temperature and wind profiles, precipitation, water and energy fluxes, turbulence components, soil temperature profiles and soil heat fluxes, radiation fluxes, and visibility. A tree has been instrumented to measure stem profiles of temperature, light intensity, and water content in cryptogamic covers. The trace gas measurements comprise continuous monitoring of carbon dioxide, carbon monoxide, methane, and ozone at 5 to 8 different heights, complemented by a variety of additional species measured during intensive campaigns (e.g., VOC, NO, NO2, and OH reactivity). Aerosol optical, microphysical, and chemical measurements are made above the canopy as well as in the canopy space. They include light scattering and absorption, aerosol fluorescence, number and volume size distributions, chemical composition, cloud

  8. Relationship between Amazon biomass burning aerosols and rainfall over La Plata Basin

    Science.gov (United States)

    Camponogara, G.; Silva Dias, M. A. F.; Carrió, G. G.

    2013-09-01

    High aerosol loads are discharged into the atmosphere by biomass burning in Amazon and Central Brazil during the dry season. These particles can interact with clouds as cloud condensation nuclei (CCN) changing cloud microphysics and radiative properties and, thereby, affecting the radiative budget of the region. Furthermore, the biomass burning aerosols can be transported by the low level jet (LLJ) to La Plata Basin where many mesoscale convective systems (MCS) are observed during spring and summer. This work proposes to investigate whether the aerosols from biomass burning may affect the MCS in terms of rainfall over La Plata Basin during spring. Since the aerosol effect is very difficult to isolate because convective clouds are very sensitive to small environment disturbances, detailed analyses using different techniques are used. The binplot, 2D histograms and combined empirical orthogonal function (EOF) methods are used to separate certain environment conditions with the possible effects of aerosol loading. Reanalysis 2, TRMM-3B42 and AERONET data are used from 1999 up to 2012 during September-December. The results show that there are two patterns associated to rainfall-aerosol interaction in La Plata Basin: one in which the dynamic conditions are more important than aerosols to generate rain; and a second one where the aerosol particles have a role in rain formation, acting mainly to suppress rainfall over La Plata Basin.

  9. Relationship between Amazon biomass burning aerosols and rainfall over La Plata Basin

    Directory of Open Access Journals (Sweden)

    G. Camponogara

    2013-09-01

    Full Text Available High aerosol loads are discharged into the atmosphere by biomass burning in Amazon and Central Brazil during the dry season. These particles can interact with clouds as cloud condensation nuclei (CCN changing cloud microphysics and radiative properties and, thereby, affecting the radiative budget of the region. Furthermore, the biomass burning aerosols can be transported by the low level jet (LLJ to La Plata Basin where many mesoscale convective systems (MCS are observed during spring and summer. This work proposes to investigate whether the aerosols from biomass burning may affect the MCS in terms of rainfall over La Plata Basin during spring. Since the aerosol effect is very difficult to isolate because convective clouds are very sensitive to small environment disturbances, detailed analyses using different techniques are used. The binplot, 2D histograms and combined empirical orthogonal function (EOF methods are used to separate certain environment conditions with the possible effects of aerosol loading. Reanalysis 2, TRMM-3B42 and AERONET data are used from 1999 up to 2012 during September-December. The results show that there are two patterns associated to rainfall-aerosol interaction in La Plata Basin: one in which the dynamic conditions are more important than aerosols to generate rain; and a second one where the aerosol particles have a role in rain formation, acting mainly to suppress rainfall over La Plata Basin.

  10. The recent extreme hydrological events in the Western Amazon Basin: The role of the Pacific and Atlantic Oceans

    Science.gov (United States)

    Espinoza, J.; Ronchail, J.; Guyot, J.; Santini, W.; Lavado, W.; Ore-Hybam Observatory

    2013-05-01

    The Peruvian Amazonas River, the main western tributary of the Amazon basin, has a huge drainage (750 000 km2, 50% of which lies in the Andes) and a mean discharge estimated in 32 000 m3/s, which correspond to 15% of the Amazon discharge at the estuary. Recently, in a context of significant discharge diminution during the low-water season (1970-2012), severe hydrological events, as intense droughts and floods, have been reported in the Peruvian Amazonas River. As they have not been always observed in other regions of the Amazon basin and because they have strong impacts on vulnerable riverside residents, we shall focus on the origin and the predictability of the western Amazon extremes, providing a review of the main findings about the climate features during recent extreme hydrological events in western Amazon. While the lowest discharge value was observed in September 2010 (8 300 m3/s) at the hydrological Tamshiyacu station (near to Iquitos city), a rapid transition toward a high discharge was noticed in April 2011 (45 000 m3/s). Finally, in April 2012, during the on going high waters period, the Amazonas River is experimenting its historical highest discharge (55 000 m3/s). Our work is based on several datasets including in-situ discharge and rainfall information from ORE-HYBAM observatory. Extreme droughts (1995, 2005 and 2010) are generally associated with positive SST anomalies in the tropical North Atlantic and weak trade winds and water vapor transport toward the western Amazon, which, in association with increased subsidence over central and southern Amazon, explain the lack of rainfall and very low discharge values. But, in 1998, toward the end of the 1997-98 El Niño event, the drought has been more likely related to an anomalous divergence of water vapor in the western Amazon that is characteristic of a warm event in the Pacific. The years with a rapid transition form low waters to very high floods (e.g. September 2010 to April 2011) are characterized

  11. Forest response to increased disturbance in the Central Amazon and comparison to Western Amazonian forests

    Directory of Open Access Journals (Sweden)

    J. A. Holm

    2014-05-01

    Full Text Available Uncertainties surrounding vegetation response to increased disturbance rates associated with climate change remains a major global change issue for Amazon forests. Additionally, turnover rates computed as the average of mortality and recruitment rates in the Western Amazon basin are doubled when compared to the Central Amazon, and notable gradients currently exist in specific wood density and aboveground biomass (AGB between these two regions. This study investigates the extent to which the variation in disturbance regimes contributes to these regional gradients. To address these issues, we evaluated disturbance-recovery processes under two scenarios of increased disturbance rates in a complex Central Amazon forest using first ZELIG-TROP, a dynamic vegetation gap model which we calibrated using long-term inventory data, and second using the Community Land Model (CLM, a global land surface model that is part of the Community Earth System Model (CESM. Upon doubling the mortality rate in the Central Amazon to mirror the natural disturbance regime in the Western Amazon of ∼2% mortality, at steady-state, AGB significantly decreased by 41.9% and there was no significant difference between the modeled AGB of 104 Mg C ha−1 and empirical AGB from the western Amazon datasets of 107 Mg C ha−1. We confirm that increases in natural disturbance rates in the Central Amazon will result in terrestrial carbon loss associated with higher turnover. However, different processes were responsible for the reductions in AGB between the models and empirical datasets. We observed that with increased turnover, the subsequent decrease in wood density drives the reduction in AGB in empirical datasets. However, decrease in stand basal area was the driver of the drop in AGB in ZELIG-TROP, and decreased leaf area index (LAI was the driver in CLM. Further comparisons found that stem density, specific wood density, and basal area growth rates differed between the two

  12. Isotope geochemistry of the Amazon Basin: A reconnaissance

    Science.gov (United States)

    Longinelli, A.; Edmond, J. M.

    1983-04-01

    On the transects of the Amazon River made by the Alpha Helix in 1976 and 1977, an extensive suite of samples was collected for isotopic analyses. The water isotopes (18O/16O, D/H) were determined in atmospheric water vapour and in river, rain, and leaf waters. 13C/12C ratios were measured in the dissolved and atmospheric CO2. Determinations were made of 34S/32S and oxygen isotopes in dissolved sulphate. The effect of `continentality' on the water isotopes is minor reflecting the large scale recycling by evapotranspiration from the huge area of forest within the basin. Variations in the isotopic abundances between 1976 (June-July, dry season) and 1977 (May-June, end of wet season) are consistent with the changes in meteorological conditions. The isotopic composition of the CO2, both atmospheric and dissolved, is dominated by biological effects. In 1976 the dissolved CO2 showed downstream variations from -14‰ at Iquitos in Peru to -22‰ in the lower reaches. In 1977, no systematic trend was apparent, the data ranging around -19‰. The values for atmospheric CO2 decrease inland from marine values at the mouth to around -15‰ at Manaus. During the dry season (1976) the values in the interior, western basin were homogeneous at -20‰. In the wet season there were considerable variations reflecting atmospheric instabilities with the average value being about -13‰. The sulphur isotopic composition of the dissolved sulphate is remarkably uniform at around 7‰. In 1977 the 18O values in the sulphate decreased systematically downstream from 8‰ in Peru to 3‰ at the mouth, consistent with a progressive, redox-mediated exchange with water and dissolved oxygen. In 1977 the values increased to over 11‰, apparently indicating exchange with a highly fractionated reservoir of dissolved oxygen perhaps in the semireducing environment of the flood plain lakes.

  13. Isotope geochemistry of the Amazon Basin: A reconnaissance

    International Nuclear Information System (INIS)

    On the transects of the Amazon River made by the Alpha Helix in 1976 and 1977, an extensive suite of samples was collected for isotopic analyses. The water isotopes (18O/16O, D/H) were determined in atmospheric water vapour and in river, rain, and leaf waters. 13C/12C ratios were measured in the dissolved and atmospheric CO2. Determinations were made of 34S/32S and oxygen isotopes in dissolved sulphate. The effect of 'continentality' on the water isotopes is minor reflecting the large scale recycling by evapotranspiration from the huge area of forest within the basin. Variations in the isotopic abundances between 1976 (June--July, dry season) and 1977 (May--June, end of wet season) are consistent with the changes in meteorological conditions. The isotopic composition of the CO2, both atmospheric and dissolved, is dominated by biological effects. In 1976 the dissolved CO2 showed downstream variations from -14X at Iquitos in Peru to -22X in the lower reaches. In 1977, no systematic trend was apparent, the data ranging around -19X. The values for atmospheric CO2 decrease inland from marine values at the mouth to around -15X at Manaus. During the dry season (1976) the values in the interior, western basin were homogeneous at -20X. In the wet season there were considerable variations reflecting atmospheric instabilities with the average value being about -13X. The sulphur isotopic composition of the dissolved sulphate is remarkably uniform at around 7X. In 1977 the 18O values in the sulphate decreased systematically downstream from 8X in Peru to 3X at the mouth, consistent with a progressive redox-mediated exchange with water and dissolved oxygen. In 1977 the values increased to over 11X, apparently indicating exchange with a highly fractionated reservoir of dissolved oxygen perhaps in the semireducing environment of the flood plain lakes

  14. Surface freshwater storage and dynamics in the Amazon basin during the 2005 exceptional drought

    International Nuclear Information System (INIS)

    The Amazon river basin has been recently affected by extreme climatic events, such as the exceptional drought of 2005, with significant impacts on human activities and ecosystems. In spite of the importance of monitoring freshwater stored and moving in such large river basins, only scarce measurements of river stages and discharges are available and the signatures of extreme drought conditions on surface freshwater dynamics at the basin scale are still poorly known. Here we use continuous multisatellite observations of inundation extent and water levels between 2003 and 2007 to monitor monthly variations of surface water storage at the basin scale. During the 2005 drought, the amount of water stored in the river and floodplains of the Amazon basin was ∼130 km3 (∼70%) below its 2003–7 average. This represents almost a half of the anomaly of minimum terrestrial water stored in the basin as estimated using the Gravity Recovery and Climate Experiment (GRACE) data. (letter)

  15. The role of Amazon Basin on the atmospheric branch of the hydrological cycle

    Science.gov (United States)

    Nieto, R. O.; Drumond, A.; Gimeno, L.

    2013-05-01

    In this work we use an objective 3-D Lagrangian model (FLEXPART) to investigate the role of Amazon Basin as source and sink of moisture in the hydrological cycle along the year. The method is based on the movement of a large number of air particles using 3D data from ERA40 reanalysis. The flow is described by the position of the particles and the time. The increases and decreases in moisture along the trajectory can be calculated through changes in specific humidity (q) with time (being recorded every 6 hours). Adding these changes for all the air particles residing in the atmospheric column over an area, we can obtain a measure of the surface freshwater flux E-P (the evaporation minus the precipitation rate). For this study we track (E-P) from Amazon Basin backwards and forwards in time along the trajectories, limiting the transport times to 10 days. Climatological monthly (E-P) fields of the backwards and forwards trajectories were calculated for the period from 1980 to 1999. The backwards tracking allows us to identify where the particles gain humidity along their trajectories towards the target area, regions hereafter denominated as sources of moisture. On the other hand, the forwards method allows to investigate the role of the basin as source of moisture, identifying those particles that leave it and following them to found where they lose moisture. Preliminary analysis suggests the role of the Tropical Atlantic (TA) as one of the most important external sources of moisture for Amazon Basin. Northern TA contributes mainly during the Austral Summer, while the contribution of southern TA is more evident in the rest of the year. It seems that Amazon receives some contribution of moisture from La Plata Basin, except during Summer months. Some moisture from the Pacific South American coast also reaches Amazon along the year. Analysing the role of Amazon Basin as a source of moisture, forwards tracking suggests that its main contribution occurs for southeastern

  16. Windthrows increase soil carbon stocks in a central Amazon forest

    Science.gov (United States)

    dos Santos, Leandro T.; Magnabosco Marra, Daniel; Trumbore, Susan; de Camargo, Plínio B.; Negrón-Juárez, Robinson I.; Lima, Adriano J. N.; Ribeiro, Gabriel H. P. M.; dos Santos, Joaquim; Higuchi, Niro

    2016-03-01

    Windthrows change forest structure and species composition in central Amazon forests. However, the effects of widespread tree mortality associated with wind disturbances on soil properties have not yet been described in this vast region. We investigated short-term effects (7 years after disturbance) of widespread tree mortality caused by a squall line event from mid-January of 2005 on soil carbon stocks and concentrations in a central Amazon terra firme forest. The soil carbon stock (averaged over a 0-30 cm depth profile) in disturbed plots (61.4 ± 8.2 Mg ha-1, mean ±95 % confidence interval) was marginally higher (p = 0.09) than that from undisturbed plots (47.7 ± 13.6 Mg ha-1). The soil organic carbon concentration in disturbed plots (2.0 ± 0.17 %) was significantly higher (p < 0.001) than that from undisturbed plots (1.36 ± 0.24 %). Moreover, soil carbon stocks were positively correlated with soil clay content (r2 = 0.332, r = 0.575 and p = 0.019) and with tree mortality intensity (r2 = 0.257, r = 0.506 and p = 0.045). Our results indicate that large inputs of plant litter associated with large windthrow events cause a short-term increase in soil carbon content, and the degree of increase is related to soil clay content and tree mortality intensity. The higher carbon content and potentially higher nutrient availability in soils from areas recovering from windthrows may favor forest regrowth and increase vegetation resilience.

  17. Radon concentrations profiles over the brazilian Amazon basin during wet season

    International Nuclear Information System (INIS)

    Atmospheric radon measurements were performed airborne in the Brazilian Amazon Basin during the wet season ABLE-2B experiment. The vertical profiles of radon showed a small decrease of concentration with increasing altitude at a rate varying from 6.5 to 11 x 10 -2 Bq m-3 km-1. The calculation of the flux balance of radon in the troposphere above the Amazon Basin indicated a residual flux at the upper boundary of the measurement domain (6 km) of 0.14 atom cm-2 s-1. This residue may be associated with the turbulent transport of radon due to cloud activity. (author)

  18. 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

  19. Relationship between Amazon biomass burning aerosols and rainfall over the La Plata Basin

    Science.gov (United States)

    Camponogara, G.; Silva Dias, M. A. F.; Carrió, G. G.

    2014-05-01

    High aerosol loads are discharged into the atmosphere by biomass burning in the Amazon and central Brazil during the dry season. These particles can interact with clouds as cloud condensation nuclei (CCN) changing cloud microphysics and radiative properties and, thereby, affecting the radiative budget of the region. Furthermore, the biomass burning aerosols can be transported by the low-level jet (LLJ) to the La Plata Basin, where many mesoscale convective systems (MCS) are observed during spring and summer. This work proposes to investigate whether the aerosols from biomass burning may affect the MCS in terms of rainfall over the La Plata Basin during spring. Aerosol effects are very difficult to isolate because convective clouds are very sensitive to small environment disturbances; for that reason, detailed analyses using different techniques are used. The binplot, 2-D histograms and combined empirical orthogonal function (EOF) methods are used to identify certain environmental conditions with the possible effects of aerosol loading. Reanalysis 2, TRMM-3B42 and AERONET data are used from 1999 up to 2012 during September-December. The results show that there are two patterns associated with rainfall-aerosol interaction in the La Plata Basin: one in which the dynamic conditions are more important than aerosols to generation of rain; and a second one where the aerosol particles have a more important role in rain formation, acting mainly to suppress rainfall over the La Plata Basin. However, these results need further investigation to strengthen conclusions, especially because there are limitations and uncertainties in the methodology and data set used.

  20. Geology, Soils and Basin-wide variations in Amazon Forest Structure and function

    Science.gov (United States)

    Quesada, Carlos Alberto; Phillips, Oliver; Lopes-Gonzales, Gabriela; Lloyd, Jon; Rainfor Team

    2015-04-01

    Forest productivity, tree turnover time and above ground biomass vary across the Amazon Basin in an east-west gradient in a pattern which coincides with variations in soil nutrient availability and geology. Forest productivity rates are higher on the most nutrient rich soils close to the Andes while is lower in the ancient, highly weathered soils of central Amazonia. On the other hand above ground biomass is lower in the most productive forests and higher on the least, this being a consequence of higher tree turnover rates in the forests over less weathered and nutrient rich soils. Major geological events have influenced Amazonian soil characteristics profoundly and play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. Here we show how geology and soil development combine to shape the functioning of Amazonian forests and its carbon stocks and fluxes. To assess the importance of edaphic properties in affect forest structure and dynamics, soil samples were collected in a total of 154 different forest plots across nine different Amazonian countries. Samples were analyzed for exchangeable cations, C, N, pH with various P fractions and soil physical properties also determined. Overall, forest structure and dynamics were found to be strongly and quantitatively related to edaphic conditions.

  1. Spectral dependence of aerosol light absorption over the Amazon Basin

    Science.gov (United States)

    Rizzo, L. V.; Correia, A. L.; Artaxo, P.; Procópio, A. S.; Andreae, M. O.

    2011-09-01

    In this study, we examine the spectral dependence of aerosol absorption at different sites and seasons in the Amazon Basin. The analysis is based on measurements performed during three intensive field experiments at a pasture site (Fazenda Nossa Senhora, Rondônia) and at a primary forest site (Cuieiras Reserve, Amazonas), from 1999 to 2004. Aerosol absorption spectra were measured using two Aethalometers: a 7-wavelength Aethalometer (AE30) that covers the visible (VIS) to near-infrared (NIR) spectral range, and a 2-wavelength Aethalometer (AE20) that measures absorption in the UV and in the NIR. As a consequence of biomass burning emissions, about 10 times greater absorption values were observed in the dry season in comparison to the wet season. Power law expressions were fitted to the measurements in order to derive the absorption Ångström exponent, defined as the negative slope of absorption versus wavelength in a log-log plot. At the pasture site, about 70 % of the absorption Ångström exponents fell between 1.5 and 2.5 during the dry season, indicating that biomass burning aerosols have a stronger spectral dependence than soot carbon particles. Ångström exponents decreased from the dry to the wet season, in agreement with the shift from biomass burning aerosols, predominant in the fine mode, to biogenic and dust aerosols, predominant in the coarse mode. The lowest absorption Ångström exponents (90 % of data below 1.5) were observed at the forest site during the dry season. Also, results indicate that low absorption coefficients were associated with low Ångström exponents. This finding suggests that biogenic aerosols from Amazonia have a weaker spectral dependence for absorption than biomass burning aerosols, contradicting our expectations of biogenic particles behaving as brown carbon. In a first order assessment, results indicate a small (<1 %) effect of variations in absorption Ångström exponents on 24-h aerosol forcings, at least in the spectral

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

    OpenAIRE

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

    2015-01-01

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

  3. Water balance in the amazon basin from a land surface model ensemble

    OpenAIRE

    Getirana, ACV; E. Dutra; Guimberteau, M.; J. Kam; Li, HY; B. Decharme; Zhang, Z; A. Ducharne; A. Boone; Balsamo, G.; Rodell, M.; Toure, AM; Xue, Y.; Peters-Lidard, CD; Kumar, SV

    2014-01-01

    © 2014 American Meteorological Society. 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. M...

  4. 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

  5. Description of Lutzomyia (Trichophoromyia) nautaensis n. sp. (Diptera: Psychodidae) from the Peruvian Amazon Basin.

    Science.gov (United States)

    Fernandez, Roberto; Lopez, Victor; Cardenas, Roldan; Requena, Edwin

    2015-07-01

    A new species of sand fly, which we describe as Lutzomyia (Trichophoromyia) nautaensis n. sp., was collected in the northern Peruvian Amazon Basin. In this region of Peru, cutaneous leishmaniasis is transmitted primarily by anthropophilic sand flies; however, zoophilic sand flies of the subgenus Trichophoromyia may also be incriminated in disease transmission. Detection of Leishmania spp. in Lutzomyia auraensis Mangabeira captured in the southern Peruvian Amazon indicates the potential of this and other zoophilic sand flies for human disease transmission, particularly in areas undergoing urban development. Herein, we describe Lutzomyia (Trichophoromyia) nautaensis n. sp., and report new records of sand flies in Peru. PMID:26335468

  6. Indications of regional scale groundwater flows in the Amazon Basins: Inferences from results of geothermal studies

    Science.gov (United States)

    Pimentel, Elizabeth T.; Hamza, Valiya M.

    2012-08-01

    The present work deals with determination groundwater flows in the Amazon region, based on analysis of geothermal data acquired in shallow and deep wells. The method employed is based on the model of simultaneous heat transfer by conduction and advection in permeable media. Analysis of temperature data acquired in water wells indicates down flows of groundwaters with velocities in excess of 10-7 m/s at depths less than 300 m in the Amazonas basin. Bottom-hole temperature (BHT) data sets have been used in determining characteristics of fluid movements at larger depths in the basins of Acre, Solimões, Amazonas, Marajó and Barreirinhas. The results of model simulations point to down flow of groundwaters with velocities of the order of 10-8 to 10-9 m/s, at depths of up to 4000 m. No evidence has been found for up flow typical of discharge zones. The general conclusion compatible with such results is that large-scale groundwater recharge systems operate at both shallow and deep levels in all sedimentary basins of the Amazon region. However, the basement rock formations of the Amazon region are relatively impermeable and hence extensive down flow systems through the sedimentary strata are possible only in the presence of generalized lateral movement of groundwater in the basal parts of the sedimentary basins. The direction of this lateral flow, inferred from the basement topography and geological characteristics of the region, is from west to east, following roughly the course of surface drainage system of the Amazon River, with eventual discharge into the Atlantic Ocean. The estimated flow rate at the continental margin is 3287 m3/s, with velocities of the order of 218 m/year. It is possible that dynamic changes in the fluvial systems in the western parts of South American continent have been responsible for triggering alterations in the groundwater recharge systems and deep seated lateral flows in the Amazon region.

  7. Clay mineral composition of river sediments in the Amazon Basin

    OpenAIRE

    Guyot, Jean-Loup; Jouanneau, J.M.; Soares, L; Boaventura, G.R.; Maillet, N; Lagane, Christelle

    2007-01-01

    Clay minerals are important in evaluating the maturity of suspended sediments, weathering intensity and source area. However, there are processes that can change the mineral assemblage such as river transportation, deposition, remobilization and tributary inputs. In terms of water discharge and sediment yield, the Amazon is one of the largest rivers in the world. Most of the suspended sediments come from the Andes, crossing the lowlands before reaching the ocean. This study measures the spati...

  8. Chemical and carbon isotope composition of Varzeas sediments and its interactions with some Amazon basin rivers

    International Nuclear Information System (INIS)

    Varzea sediment samples were collected on the banks of Amazon rivers and in the most important tributaires. The samples were taken in three different river stages. The major cations, pH, total nitrogen, total phosphorus, carbon and δ13C values were determined. The concentration of major basic cations - Ca,Mg,K e Na were greater in the main channel sediments than in the tributaires. Probably the differences in the substrats geology and erosion regimes of the basins account for this patterns, generally. The major basic cation, total phosphorus and carbon concentration were lower in the low Amazon Varzeas. Between the three differents sampling periods, pratically the elements concentration in Varzea sediment was constant. Finally, the datas showed that the most parts of Varzea carbon sediment had it's origin in the fine particulated organic matter transported by the Amazon river. (C.D.G.)

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

    Directory of Open Access Journals (Sweden)

    Xiao-Peng Song

    Full Text Available 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

  10. 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. PMID

  11. Impacts of Land Use Changes on Water Balance of the Amazon Basin Using Remote Sensing

    Science.gov (United States)

    Ribeiro, C. B.; Mohanty, B.

    2013-12-01

    Current problems related to increasing deforestation in Amazon Basin and its impact to climate change are among the major challenges faced by scientific community. This has led us to study the effects of landuse/cover change in Amazonian basin for protection and proper management of water resources. The use of remote sensing data over the amazon basin provides insight into understanding the water cycle and its impact on climate change. Data at different scales are used to evaluate this hypothesis. MODIS data with 1 km resolution is used to study the land use changes from 2001 to 2012. Change detection technique is applied to evaluate time series hydrological behavior of the basin. Data from point scale and regional scale such as MODIS products and Global Land Data Assimilation System (GLDAS) and point scale data available from Experiment and Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA), HidroWeb system, the National Water Agency (ANA) and by the National Institute of Meteorology (INMET), from Brazil are used. This work aims to contribute to the current challenge of sustainability of water resources in the Amazon region because of alterations of the landuse cover.

  12. Emissions from vegetation fires and their influence on atmospheric composition over the Amazon Basin (Invited)

    Science.gov (United States)

    Andreae, M. O.; Artaxo, P.; Bela, M. M.; de Freitas, S. R.; Gerbig, C.; Longo, K. M.; Wiedemann, K. T.; Wofsy, S. C.

    2010-12-01

    Over the past decades, several campaigns have been conducted in the Amazon Basin, during which the emissions from biomass burning were characterized. Other campaigns, as well as remote sensing studies, have produced clear evidence that the budget of traces gases (including CO2) and aerosols over the Basin are strongly perturbed by vegetation fires. We will briefly review these studies and present some recent measurements made during the the Balanço Atmosférico Regional de Carbono na Amazônia (BARCA) aircraft measurement program, which consisted of two aircraft campaigns during November-December 2008 (BARCA-A) and May-June 2009 (BARCA-B). The measurements covered the altitude range from the surface up to about 4500 m, and spanned across the Amazon Basin. While our results confirm the importance of biomass burning for the atmospheric composition over the Amazon Basin in general, they also highlight some complexities. One is the influence of transatlantic transport: Amazonia is downwind of massive fire regions in Africa, and depending on season and locality, these can make an important contribution to the trace gas and aerosol burden over the Amazon Basin. Another difficulty arises from the fact that representative emission ratios for CO relative to CO2 are difficult to obtain in the field, owing to the influence of biospheric exchange on the distribution of CO2 concentrations. The consequences of these and other uncertainties for a quantitative assessment of the sources of trace gases over Amazonia and for the estimation of carbon exchange with the biosphere will be discussed.

  13. Seroprevalence of Toxoplasma gondii in free-living Amazon River dolphins (Inia geoffrensis) from central Amazon, Brazil.

    Science.gov (United States)

    Santos, P S; Albuquerque, G R; da Silva, V M F; Martin, A R; Marvulo, M F V; Souza, S L P; Ragozo, A M A; Nascimento, C C; Gennari, S M; Dubey, J P; Silva, J C R

    2011-12-29

    Toxoplasma gondii is an important pathogen in aquatic mammals and its presence in these animals may indicate the water contamination of aquatic environment by oocysts. Serum samples from 95 free-living Amazon River dolphins (Inia geoffrensis) from the Mamirauá Sustainable Development Reserve (RDSM), Tefé, Amazonas, Central Amazon, Brazil were tested for T. gondii antibodies using the modified agglutination test (MAT). Antibodies (MAT ≥ 25) to T. gondii were found in 82 (86.3%) dolphins with titers of 1:25 in 24, 1:50 in 56, and 1:500 in 2. Results suggest a high level contamination of the aquatic environment of the home range of these animals. PMID:21764516

  14. The effects of forest structure on occurrence and abundance of three owl species (Aves: Strigidae in the Central Amazon forest

    Directory of Open Access Journals (Sweden)

    Obed G. Barros

    2009-03-01

    Full Text Available We investigated how forest structure affects the occurrence and abundance of three owl species: the crested owl Lophostrix cristata Daudin, 1800, the Amazon pygmy owl Glaucidium hardyi Vielliard, 1990, and the tawny-bellied screech owl Megascops watsonii Cassin, 1849. We surveyed the owls mostly between 07:00 and 11:00 pm from July 2001 to April 2002, in eighteen 8 km transects along trails at the Ducke Reserve, Manaus, Central Amazon, Brazil. We staked out 50 x 50 m plots where the presence and absence of the owls were recorded. We compared some components of the forest structure between plots where owls were present and plots where they were absent. The spatial variation in these components were related to the occurrence and abundance of the owls using models of multiple logistic and multiple linear regressions analysis, respectively. Lophostrix cristata is rare in many other areas of the Amazon forest, but it was the most abundant in our study area. Lophostrix cristata and G. hardyi were more concentrated along the uplands (central plateau, which divide the reserve into two drainage water-basins. Megascops watsonii was distributed mainly in the southeastern part of the reserve. Glaucidium hardyi was more often found in areas with larger canopy openness. In areas with higher abundance of snags, there was significantly higher occurrence of L. cristata and M. watsonii. Megascops watsonii was also more abundant in areas with higher abundance of forest trees and in areas bearing shallower leaf litter on the forest floor. This study is the first to analyze at large spatial scale the effects of forest structure on neotropical forest top predator nocturnal birds. The results indicate that forest structure can affect the occurrence and abundance of owls in the Amazon forest.

  15. Water discharge estimates from large radar altimetry datasets in the Amazon basin

    OpenAIRE

    Getirana, A. C. V.; Peters-Lidard, C.

    2012-01-01

    In this study, we evaluate the use of a large radar altimetry dataset as a complementary gauging network capable of providing water discharge in ungauged regions within the Amazon basin. A rating-curve-based methodology is adopted to derive water discharge from altimetric data provided by Envisat at 444 virtual stations (VS). The stage-discharge relations at VS are built based on radar altimetry and outputs from a global flow routing scheme. In order to quantify the impact of modeling...

  16. TOTAL MERCURY (HgT) BIOACCUMULATION AND FISH FOOD HABITS IN NEGRO RIVER BASIN, AMAZON, BRAZIL

    OpenAIRE

    Jean Louchard Ferreira Soares; Ynglea Georgina de Freitas Goch; José Reinaldo Pacheco Peleja; Bruce Rider Forsberg; Edivaldo Júnior de Souza Lemos; Otávio Peleja de Sousa

    2016-01-01

    In the Amazon, the fish is the main nutritional source for the riverine. Thus, fish have been commonly used in environmental monitoring work to be good biomonitors. This study analyzed the total mercury concentration (THg) in fish of different species and feeding habits in order to investigate the existence of bioaccumulation in species in the basin of the Negro river and verify that the THg levels found are in accordance with the stipulated limit for consumption human. Sampling points were d...

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    M. Guimberteau

    2011-12-01

    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 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 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.

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

    Science.gov (United States)

    Pereira Nunes, Ana; Silva Dias, Maria; Anselmo, Evandro; Rodriguez, Carlos

    2016-04-01

    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.

  20. Dynamics of Dissolved Organic Matter in Amazon Basin: Insights into Negro River Contribution

    Science.gov (United States)

    Moreira-Turcq, P.; Perez, M. P.; Benedetti, M.; Oliveira, M. A.; Lagane, C.; Seyler, P.; Oliveira, E.

    2006-12-01

    The study of global carbon cycle requires a precise knowledge of spatial and temporal distributions and exportation from continents to oceans. Organic carbon fluxes represent approximately half of the total carbon budget carried by rivers. Tropical rivers transport two third of the total organic carbon discharged into the world oceans but important gaps still exist in the knowledge of the tropical river carbon biochemistry. The Amazon River is responsible for 10% of the annual amount of organic carbon transported from rivers to oceans. The most important portion of total organic matter transported in the Amazon Basin is the dissolved fraction (between 80% and 95%). Amazonian annual flux of dissolved organic matter is directly related to hydrological variations. All rivers in the Amazon basin are characterized by monomodal hydrograms, with a low water period in october/november and a high water period in may/june. Temporal variations in Amazon dissolved organic carbon (3.0 to 9.1 mg l^{- 1}) are mainly controled by Negro River inputs. DOC and DON contributions from the Negro River can vary between 120 kgC s-1 and 520 kg C s-1, and between 5 kgN s--1 and 15 kgN s-1, during low and high water period, respectivelly. In the Negro River, during high water stages, while DOC concentrations are stable from the upstream stations to the downstream ones (about 11 mg l-1), discharge increases from 16000 to 46000 m3 s-1 and NOD can quintuple from upstream (0.071 mg l-1) to downstream (0.341 mg l-1). Then the nature of dissolved organic matter is variable (C/N ratio varied from 33 to 120 from upstream to downstream). During low water stages DOC concentrations are lower (mean DOC of 8.1 mg l-1) while DON is in the same range, discharge is about 10000 m3 s-1 at downstream stations of Negro River and the C/N ratio is lower and steadier along the River. Finaly, despite a low basin surface (12%) compared with the two other main Amazon tributaries, Solimões and Madeira Rivers, and a

  1. Geochemical and isotopic characterization of the Bodélé Depression dust source and implications for transatlantic dust transport to the Amazon Basin

    Science.gov (United States)

    Abouchami, Wafa; Näthe, Kerstin; Kumar, Ashwini; Galer, Stephen J. G.; Jochum, Klaus Peter; Williams, Earle; Horbe, Adriana M. C.; Rosa, João W. C.; Balsam, William; Adams, David; Mezger, Klaus; Andreae, Meinrat O.

    2013-10-01

    The Bodélé Depression (Chad) in the central Sahara/Sahel region of Northern Africa is the most important source of mineral dust to the atmosphere globally. The Bodélé Depression is purportedly the largest source of Saharan dust reaching the Amazon Basin by transatlantic transport. Here, we have undertaken a comprehensive study of surface sediments from the Bodélé Depression and dust deposits (Chad, Niger) in order to characterize geochemically and isotopically (Sr, Nd and Pb isotopes) this dust source, and evaluate its importance in present and past African dust records. We similarly analyzed sedimentary deposits from the Amazonian lowlands in order to assess postulated accumulation of African mineral dust in the Amazon Basin, as well as its possible impact in fertilizing the Amazon rainforest. Our results identify distinct sources of different ages and provenance in the Bodélé Depression versus the Amazon Basin, effectively ruling out an origin for the Amazonian deposits, such as the Belterra Clay Layer, by long-term deposition of Bodélé Depression material. Similarly, no evidence for contributions from other potential source areas is provided by existing isotope data (Sr, Nd) on Saharan dusts. Instead, the composition of these Amazonian deposits is entirely consistent with derivation from in-situ weathering and erosion of the Precambrian Amazonian craton, with little, if any, Andean contribution. In the Amazon Basin, the mass accumulation rate of eolian dust is only around one-third of the vertical erosion rate in shield areas, suggesting that Saharan dust is "consumed" by tropical weathering, contributing nutrients and stimulating plant growth, but never accumulates as such in the Amazon Basin. The chemical and isotope compositions found in the Bodélé Depression are varied at the local scale, and have contrasting signatures in the "silica-rich" dry lake-bed sediments and in the "calcium-rich" mixed diatomites and surrounding sand material. This

  2. Groundwater dynamics in the Amazon basin from remotely sensed observations and hydrological models

    Science.gov (United States)

    Frappart, Frédéric; Papa, Fabrice; Tomasella, Javier; Ramillien, Guillaume; Güntner, Andreas; Emilio, Thaise; Schietti, Juliana; da Silva Carvalho, João

    2014-05-01

    Groundwater plays a key role in the terrestrial hydrological cycle and the water balance on the continents. It accounts for more than 30% (i.e., 8,000,000 km3 to 10,000,000 km3) of global fresh-water resources, and is also the major resource of water supply for 40% of the world's population and 50% of the world's food production. However, groundwater storage and its variations are still poorly known at global scale due to the limited extent of current monitoring networks. Most of the studies on geohydrology in the Amazon basin were carried out at local scale except a recent study that pointed out evidences on regional scale groundwater flows using a geothermal method. Gravimetry from space offers the unique opportunity to monitor water resources at basin to continental scales. The Gravity Recovery And Climate Experiment (GRACE) mission, launched in 2002, detects tiny changes in the Earth's gravity field which can be related to spatio-temporal variations of TWS at monthly or sub-monthly time-scales. Variations in groundwater storage (GW) can be separated from the TWS anomalies measured by GRACE using external information on the other hydrological reservoirs such as in situ observations, model outputs, or both. Very few studies have been undertaken yet in large river basins characterized by extensive wetlands and floodplains, due to the lack of reliable and timely information about the extent, spatial distribution, as well as the amount of water stored in wetlands and floods and their temporal variations. Using multi-satellite observations for surface water storage (SW) and hydrological outputs for soil moisture (SM), variations in GW were estimated in the Negro basin, the second largest tributary of the Amazon in terms of discharge. Here, the same approach was applied in the whole Amazon basin, allowing to estimate the contribution of each hydrological reservoir to TWS, to monitor its time variations, and to map the annual changes in the aquifers over 2003

  3. Potential negative effects of groundwater dynamics on dry season convection in the Amazon River basin

    Science.gov (United States)

    Lin, Yen-Heng; Lo, Min-Hui; Chou, Chia

    2016-02-01

    Adding a groundwater component to land surface models affects modeled precipitation. The additional water supply from the subsurface contributes to increased water vapor in the atmosphere, resulting in modifications of atmospheric convection. This study focuses on how groundwater dynamics affect atmospheric convection in the Amazon River basin (ARB) during July, typically the driest month. Coupled groundwater-land-atmosphere model simulations show that groundwater storage increases evapotranspiration rates (latent heat fluxes) and lowers surface temperatures, which increases the surface pressure gradient and thus, anomalous surface divergence. Therefore, the convection over the Southern Hemispheric ARB during the dry season becomes weaker when groundwater dynamics are included in the model. Additionally, the changes in atmospheric vertical water vapor advection are associated with decreases in precipitation that results from downwelling transport anomalies. The results of this study highlight the importance of subsurface hydrological processes in the Amazon climate system, with implications for precipitation changes during the dry season, observed in most current climate models.

  4. Biogenic cloud nuclei in the central Amazon during the transition from wet to dry season

    Science.gov (United States)

    Whitehead, James D.; Darbyshire, Eoghan; Brito, Joel; Barbosa, Henrique M. J.; Crawford, Ian; Stern, Rafael; Gallagher, Martin W.; Kaye, Paul H.; Allan, James D.; Coe, Hugh; Artaxo, Paulo; McFiggans, Gordon

    2016-08-01

    The Amazon basin is a vast continental area in which atmospheric composition is relatively unaffected by anthropogenic aerosol particles. Understanding the properties of the natural biogenic aerosol particles over the Amazon rainforest is key to understanding their influence on regional and global climate. While there have been a number of studies during the wet season, and of biomass burning particles in the dry season, there has been relatively little work on the transition period - the start of the dry season in the absence of biomass burning. As part of the Brazil-UK Network for Investigation of Amazonian Atmospheric Composition and Impacts on Climate (BUNIAACIC) project, aerosol measurements, focussing on unpolluted biogenic air masses, were conducted at a remote rainforest site in the central Amazon during the transition from wet to dry season in July 2013. This period marks the start of the dry season but before significant biomass burning occurs in the region. Median particle number concentrations were 266 cm-3, with size distributions dominated by an accumulation mode of 130-150 nm. During periods of low particle counts, a smaller Aitken mode could also be seen around 80 nm. While the concentrations were similar in magnitude to those seen during the wet season, the size distributions suggest an enhancement in the accumulation mode compared to the wet season, but not yet to the extent seen later in the dry season, when significant biomass burning takes place. Submicron nonrefractory aerosol composition, as measured by an aerosol chemical speciation monitor (ACSM), was dominated by organic material (around 81 %). Aerosol hygroscopicity was probed using measurements from a hygroscopicity tandem differential mobility analyser (HTDMA), and a quasi-monodisperse cloud condensation nuclei counter (CCNc). The hygroscopicity parameter, κ, was found to be low, ranging from 0.12 for Aitken-mode particles to 0.18 for accumulation-mode particles. This was consistent

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

    Science.gov (United States)

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

    2015-03-01

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

  6. Water balance in the Amazon basin from a land surface model ensemble

    Energy Technology Data Exchange (ETDEWEB)

    Getirana, Augusto; Dutra, Emanuel; Guimberteau, Matthieu; Kam, Jonghun; Li, Hongyi; Decharme, Bertrand; Zhang, Zhengqiu J.; Ducharne, Agnes; Boone, Aaron; Balsamo, Gianpaolo; Rodell, Matthew; Mounirou Toure, Ally; Xue, Yongkang; Peters-Lidard, Christa D.; Kumar, Sujay V.; Arsenault, Kristi Rae; Drapeau, Guillaume; Leung, Lai-Yung R.; Ronchail, Josyane; Sheffield, Justin

    2014-12-06

    Despite recent advances in modeling and remote sensing of land surfaces, estimates of the global water budget are still fairly uncertain. The objective of this study is to evaluate the water budget of the Amazon basin based on several state-of-the-art land surface model (LSM) outputs. Water budget variables [total water storage (TWS), evapotranspiration (ET), surface runoff (R) and baseflow (B)] are evaluated at the basin scale using both remote sensing and in situ data. Fourteen LSMs were run using meteorological forcings at a 3-hourly time step and 1-degree spatial resolution. Three experiments are performed using precipitation which has been rescaled to match monthly global GPCP and GPCC datasets and the daily HYBAM dataset for the Amazon basin. R and B are used to force the Hydrological Modeling and Analysis Platform (HyMAP) river routing scheme and simulated discharges are compared against observations at 165 gauges. Simulated ET and TWS are compared against FLUXNET and MOD16A2 evapotranspiration, and GRACE TWS estimates in different catchments. At the basin scale, simulated ET ranges from 2.39mm.d-1 to 3.26mm.d-1 and a low spatial correlation between ET and P indicates that evapotranspiration does not depend on water availability over most of the basin. Results also show that other simulated water budget variables vary significantly as a function of both the LSM and precipitation used, but simulated TWS generally agree at the basin scale. The best water budget simulations resulted from experiments using the HYBAM dataset, mostly explained by a denser rainfall gauge network the daily rescaling.

  7. Trace elements in atmospheric aerosols from background regions and biomass burning from the Amazon Basin

    International Nuclear Information System (INIS)

    Aerosol particles from the tropical rain forest and from savannah biomass burning were collected in several experiments in the Amazon Basin. The size distribution of atmospheric trace elements was measured under both background and biomass burning conditions. Sampling from aircraft was performed over a large area of the Amazon Basin in August/September 1991. The aerosol mass concentration, black carbon and trace element concentrations were determined for fine and coarse aerosol particles. Particle induced X ray emission (PIXE) was used to measure the concentrations of up to 22 elements: Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Zr and Pb. During the dry season, when most of the biomass burning occurs, the concentration of inhalable particles exceeds 300 μg/m3 in regions far from the direct influence of emissions from biomass burning. Large amounts of fine particles are injected into the atmosphere, where they can travel over long distances. These particles are rich in K, P, S, Ca, Mg, Cl, Si, Zn, Rb, Sr, Zr and other trace elements. The emissions of trace elements and heavy metals into the global atmosphere owing to biomass burning are very significant, but are currently not considered in global atmospheric heavy metal inventories. Several essential nutrients, such as P, K, S and others, are transported into the atmosphere as a result of biomass burning processes. Most of the particles are water soluble and can be active as cloud condensation nuclei, with the potential to change the cloud formation mechanisms in the Amazon Basin and other regions of the planet. 22 refs, 5 figs, 1 tab

  8. Concept design of a clinic ship for the health care system in the Peruvian Amazon basin

    OpenAIRE

    Mendoza Vassallo, Pedro Nicolás; Biot, Marco; Bresciani, Ferruccio

    2013-01-01

    In the Peruvian Amazon basin rivers are the only link among the small communities, scattered on a wide territory. With that in mind and according to the needs of local communities, a health care network system based on mobile clinic units onboard small crafts has been conceived, within a cooperation programme between the Universidad Católica Santo Toribio de Mogrovejo (Perú) and the University of Trieste (Italy). This way, patients along the inland waterways can be reached. Ships to be operat...

  9. Provenance studies in Amazon basin by means of chemical composition obtained by INAA

    International Nuclear Information System (INIS)

    This study determines the provenance of the 106 sediments samples deposited by the Solimoes and Negro rivers in the tectonic depressions in Manaus, Amazon state, Brazil. Twenty-four chemical elements in the sediment samples collected before the confluence of Negro and Solimoes rivers have been determined using instrumental neutron activation analysis, INAA. It is inferred from the multivariate statistical methods that samples from the basin of the Solimoes river and tectonic depression 1 (the most significant of the region) are not significantly different. These results indicate the contribution this river in the sedimentary fill during the evolution in the Quaternary. (author)

  10. Globalization and the Spatial Economy: Implications for the Amazon Basin in the 21st Century

    Science.gov (United States)

    Arima, E.; Walker, R.; Richards, P.

    2011-12-01

    Global demand for food and energy will increase in the next decades as world population grows, incomes in developing countries rise, and new energy sources from biofuels are sought. Despite gains in productivity, much of the future demand for those agricultural products will be met by bringing new lands into production. Tropical forests, and in particular the Brazilian Amazon, the focus of our article, are already facing pressures from expanding production of soy, beef, cotton, and biofuels as deforestation advances the agricultural frontier. This article begins by reviewing the recent literature and provides evidences of indirect land cover change in the Amazon driven by the tandem soy - cattle, whereby mechanized agriculture encroaches on existing pastures, displacing them to the Amazonian frontier. We then consider conditions in the spatial economy that potentially inhibit ongoing forest loss. In particular, we address the prospect of forest transition in the Amazon basin. This necessitates a review of the so-called Borlaug hypothesis, and the circumstances under which land sparing occurs. Land sparing, a sufficient if not necessary condition for forest transition, represents a potential solution to environmental problems associated with land change, one that promotes sustainability by furthering rural development with improved technologies. The paper concludes by contrasting the current Brazilian agricultural and environmental policies with the conditions set in the previous section.

  11. Floristic overview of the epiphytic bryophytes of terra firme forests across the Amazon basin

    Directory of Open Access Journals (Sweden)

    Sylvia Mota de Oliveira

    2013-06-01

    Full Text Available Epiphytic bryophyte communities in terra firme forests of the Amazon region were investigated for the first time through standardized sampling across the Amazon basin. The sampling was carried out at nine localities, where bryophytes were collected in five height zones, from the forest floor to the canopy of eight canopy trees per locality. The sampling generated 3104 records, identifying 222 species and 39 morphospecies, within 29 families. The most common families were Lejeuneaceae (in 55%, Calymperaceae (in 8%, Leucobryaceae (in 4% and Sematophyllaceae (in 4%. Richness and species composition did not show any geographical gradient. The bryoflora was significantly richer in the localities of Saül, in French Guiana, and Tiputini, in Ecuador, than in the other localities, probably due to differences in local climatic conditions. Among the 155 species recorded for more than one locality, 57 were classified as specialists. A total of 29 species (among which 3 were unidentified were sampled only in the canopy, which reinforces the importance of canopy sampling for the study of epiphytic bryophytes in the Amazon.

  12. Theorizing Land Cover and Land Use Change: The Peasant Economy of Colonization in the Amazon Basin

    Science.gov (United States)

    Caldas, Marcellus; Walker, Robert; Arima, Eugenio; Perz, Stephen; Aldrich, Stephen; Simmons, Cynthia

    2007-01-01

    This paper addresses deforestation processes in the Amazon basin. It deploys a methodology combining remote sensing and survey-based fieldwork to examine, with regression analysis, the impact household structure and economic circumstances on deforestation decisions made by colonist farmers in the forest frontiers of Brazil. Unlike most previous regression-based studies, the methodology implemented analyzes behavior at the level of the individual property. The regressions correct for endogenous relationships between key variables, and spatial autocorrelation, as necessary. Variables used in the analysis are specified, in part, by a theoretical development integrating the Chayanovian concept of the peasant household with spatial considerations stemming from von Thuenen. The results from the empirical model indicate that demographic characteristics of households, as well as market factors, affect deforestation in the Amazon. Thus, statistical results from studies that do not include household-scale information may be subject to error. From a policy perspective, the results suggest that environmental policies in the Amazon based on market incentives to small farmers may not be as effective as hoped, given the importance of household factors in catalyzing the demand for land. The paper concludes by noting that household decisions regarding land use and deforestation are not independent of broader social circumstances, and that a full understanding of Amazonian deforestation will require insight into why poor families find it necessary to settle the frontier in the first place.

  13. Contribution of regional sources to atmospheric methane over the Amazon Basin in 2010 and 2011

    Science.gov (United States)

    Wilson, Chris; Gloor, Manuel; Gatti, Luciana V.; Miller, John B.; Monks, Sarah A.; McNorton, Joey; Bloom, A. Anthony; Basso, Luana S.; Chipperfield, Martyn P.

    2016-03-01

    We present an assessment of methane (CH4) atmospheric concentrations over the Amazon Basin for 2010 and 2011 using a 3-D atmospheric chemical transport model, two wetland emission models, and new observations made during biweekly flights made over four locations within the basin. We attempt to constrain basin-wide CH4 emissions using the observations, and since 2010 was an unusually dry year, we assess the effect of this drought on Amazonian methane emissions. We find that South American emissions contribute up to 150 ppb to concentrations at the sites, mainly originating from within the basin. Our atmospheric model simulations agree reasonably well with measurements at three of the locations (0.28 ≤ r2 ≤ 0.63, mean bias ≤ 9.5 ppb). Attempts to improve the simulated background CH4 concentration through analysis of simulated and observed sulphur hexafluoride concentrations do not improve the model performance, however. Through minimisation of seasonal biases between the simulated and observed atmospheric concentrations, we scale our prior emission inventories to derive total basin-wide methane emissions of 36.5-41.1 Tg(CH4)/yr in 2010 and 31.6-38.8 Tg(CH4)/yr in 2011. These totals suggest that the Amazon contributes significantly (up to 7%) to global CH4 emissions. Our analysis indicates that factors other than precipitation, such as temperature variations or tree mortality, may have affected microbial emission rates. However, given the uncertainty of our emission estimates, we cannot say definitively whether the noncombustion emissions from the region were different in 2010 and 2011, despite contrasting meteorological conditions between the two years.

  14. 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

  15. Isotope composition of iron delivered to the oceans by intertropical rivers: The Amazon River Basin case

    Science.gov (United States)

    Poitrasson, F.; Vieira, L. C.; Seyler, P.; dos Santos Pinheiro, G. M.; Mulholland, D. S.; Ferreira Lima, B. A.; Bonnet, M.; Martinez, J.; Prunier, J.

    2011-12-01

    Riverborne iron is a notable source for this biogeochemically key element to the oceans. Recent investigations have shown that its isotopic composition may vary significantly in oceanic waters. Hence, a proper understanding of the Fe cycle at the surface of the Earth requires a good characterization of the isotopic composition of its various reservoirs. However, as the database growths, it appears that the isotope composition of the riverborne Fe delivered to the oceans may be more varied than initially thought, in agreement with inferences from soil studies from different climatic contexts. It is therefore important to compare major rivers from different latitudes. We focused our attention on the Amazon River and its tributaries that represent ca. 20% of the freshwater delivered to the oceans by world rivers. Preliminary experiments suggest that water filtration may induce biases in stable Fe isotope composition. Therefore, we worked first on bulk waters, sampled during multidisciplinary field campaigns on the Amazon River and its tributaries, including the Solimoes, Negro, Madeira and Tapajos Rivers. Besides a complete sample physical-chemical characterization, Fe isotope determinations were conduced after water sample mineralization, iron purification and MC-ICP-MS analysis. Our first results reveal that most bulk water samples cluster close to the continental crust value (0.1% δ57FeIRMM-14) with an overall range of 0.2%. This is consistent with the restricted range found in lateritic soils elsewhere that represent 80% of the Amazon basin surface. Only black water rivers flowing over the podzols of the northern portion of the Amazon basin tend to show lighter isotopic compositions, down to -0.18%. However, sediment analyses suggest that this light Fe isotopic is lost through sedimentation on the river bed, thereby leading the waters to have Fe isotope compositions remaining close to that of the continental crust. This constant isotopic signature holds whatever

  16. Suspended sediments and organic matter in mountain headwaters of the Amazon River: Results from a 1-year time series study in the central Peruvian Andes

    Science.gov (United States)

    Townsend-Small, Amy; McClain, Michael E.; Hall, Bonnie; Noguera, Jorge L.; Llerena, Carlos A.; Brandes, Jay A.

    2008-02-01

    Few studies have examined the dynamics of sediments and suspended organic matter and their export from headwater basins in the Andes Mountains to the Amazon River, despite the fact that the Andes are the primary source of sediments to the lower Amazon basin. We measured river discharge as well as the concentration, δ 15N, δ 13C, %N, and %OC of coarse and fine suspended sediments (CSS and FSS) in the Chorobamba River, located in the central Andean Amazon of Peru. Samples were taken at least weekly over an entire year (July 2004-July 2005), with additional sampling during storms. Concentrations of particulate organic matter (POM) were generally low in the study river, with concentrations increasing by up to several orders of magnitude during episodic rain events. Because both overall flow volumes and POM concentrations increased under stormflow conditions, the export of POM was enhanced multiplicatively during these events. We estimated that a minimum of 80% of annual suspended sediment transfer occurred during only about 10 days of the year, also accounting for 74% of particulate organic carbon and 64% of particulate organic nitrogen transport. Significant differences occurred between seasons (wet and dry) for δ 13C of coarse and fine POM in the Chorobamba River, reflecting seasonal changes in organic matter sources. The time series data indicate that this Andean river exports approximately equal amounts of fine and coarse POM to the lower Amazon. The observation that the vast majority of sediments and associated OM exported from Andean rivers is mobilized during short, infrequent storm events and landslides has important implications for our understanding of Amazon geochemistry, especially in the face of incipient global change.

  17. 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. PMID:25794814

  18. Validation of SARAL/AltiKa data in the Amazon basin

    Science.gov (United States)

    Santos da Silva, Joecila; Calmant, Stephane; Medeiros Moreira, Daniel; Oliveira, Robson; Conchy, Taina; Gennero, Marie-Claude; Seyler, Frederique

    2015-04-01

    SARAL/AltiKa is a link between past missions (since it flies on the ERS-ENVISAT orbit with Ku band nadir altimeters in LRM) and future missions such as SWOT's Ka band interferometry swaths. In the present study, we compare the capability of its altimeter AltiKa to that of previous missions working in the Ku band such as ENVISAT and Jason-2 in retrieving water levels over the Amazon basin. Same as for the aforementioned preceding missions, the best results were obtained with the ICE-1 retracking algorithm. We qualitatively analyze the impact of rainfalls in the loss of measurements. Since making long -multi mission- time series is of major importance either for hydro-climatic studies or for basin management, we also present an estimate of the altimeter bias in order that the SARAL series of water level can be appended to those of these previous missions.

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

    Directory of Open Access Journals (Sweden)

    Pablo Lehmann A.

    2015-03-01

    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.

  20. 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.

  1. TOTAL MERCURY (HgT BIOACCUMULATION AND FISH FOOD HABITS IN NEGRO RIVER BASIN, AMAZON, BRAZIL

    Directory of Open Access Journals (Sweden)

    Jean Louchard Ferreira Soares

    2016-03-01

    Full Text Available In the Amazon, the fish is the main nutritional source for the riverine. Thus, fish have been commonly used in environmental monitoring work to be good biomonitors. This study analyzed the total mercury concentration (THg in fish of different species and feeding habits in order to investigate the existence of bioaccumulation in species in the basin of the Negro river and verify that the THg levels found are in accordance with the stipulated limit for consumption human. Sampling points were distributed in the basin of the Negro river during the period of high water. After the fisheries specimens were identified, measured and weighed. Then muscle samples were taken and subjected to acid digestion and analyzed by Cold Vapor Atomic Fluorescence Spectrophotometer - CVAFS. To research data was used analysis of variance and linear regression. A total of 264 specimens distributed into 10 species were analyzed, and the THg of the concentrations ranged from 0.030 for 1,670 mg.kg-1. The species Hoplias malabaricus, Serrasalmus rhombeus, Hemiodus immaculatus and Cichla temensis showed bioaccumulation. High concentrations of THg were found in carnivorous, piscivorous, planctívos and omnivores fish. No specimen showed mean concentrations of THg in violation to ANVISA, but this occurred in relation to FAO and WHO. keywords: Brazilian Amazon; biomonitoring; high waters; Hg.

  2. Improving Terrestrial Carbon and Water Simulations with Dynamic Root Distribution over the Amazon Basin

    Science.gov (United States)

    Wang, Y.; Xie, Z.; Jia, B.

    2015-12-01

    Realistic representation of roots and their behavior are important in hydrological, ecological and climate modeling. However, land surface models currently prescribe rooting profiles as a function of only the plant functional types, with no consideration of the dynamic rooting strategies in response to the changing environments. In this study, a new dynamic rooting scheme which taking the controlling effects of soil water and nitrogen on rooting strategies into account was incorporated into the version 4.5 of the Community Land Model with carbon-nitrogen interactions (CLM4.5-CN). Two pairs of experiments were conducted to study the effects of dynamic root distribution on eco-hydrological modeling for the Tapajos National Forest km83 (BRSa3) site and the Amazon Basin. For site-level comparisons, the dynamic rooting scheme can improve the carbon and water cycle modeling by reducing the root-mean-square error (RMSE) in gross primary production (GPP) by 0.4 g C m-2 day-1, net ecosystem exchange (NEE) by 1.96 g C m-2 day-1, latent heat (LE) by 5.0 W m-2, soil moisture (SM) by 0.03 m3 m-3. In the Amazon basin, the vegetation responses (including GPP and LE) to seasonal drought and server 2005 drought are also better captured with dynamic root distribution incorporated.

  3. 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).

  4. Molecular diagnosis of the arowanas Osteoglossum ferreirai Kanazawa, 1966 and O. bicirrhossum (Cuvier, 1829) from the Orinoco and Amazon River basins

    OpenAIRE

    Maria Doris Escobar L.; Farias, Izeni P.; Donald C. Taphorn B.; Miguel Landines; Tomas Hrbek

    2013-01-01

    The arowanas, fishes of Gondwanan origin, are represented in South America by the genus Osteoglossum. All species were initially reported as being exclusive to the Amazon region, with O. ferreirai restricted to the Negro River basin and O. bicirrhosum to the Amazon and Essequibo Rivers basin. Starting in the mid 1970's it was reported that O. ferreirai also occurs in the Orinoco River basin. In all regions the arowanas assumed significant socio-economic importance due to their popularity in t...

  5. 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

    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...

  6. Rivulus kirovskyi, a new killifish from the central Amazon, Brazil (Cyprinodontiformes: Rivulidae)

    OpenAIRE

    Wilson J. E. M. Costa

    2004-01-01

    Rivulus kirovskyi, new species, from the central Amazon, lower rio Negro drainage, northern Brazil, is described. It is a member of an assemblage that includes R. amanapira, R. atratus, R. ornatus, R. rectocaudatus, R. romeri, R. tecminae, and R. uakti, and is diagnosed by a unique pattern of frontal squamation and a derived color pattern of the infraorbital region. Relationships of the new species with other taxa of the group are unclear at the present. It is similar to R. atratus, R. ornatu...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-15

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

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    M. O. Andreae

    2012-03-01

    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 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 by

  11. Late Quaternary Paleohydrology of the Madre de Dios River, southwestern Amazon Basin, Peru

    Science.gov (United States)

    Rigsby, Catherine A.; Hemric, Erin M.; Baker, Paul A.

    2009-12-01

    Late Quaternary climatic and hydrologic variability triggered changes in fluvial deposition and erosion along the course of the Madre de Dios River, Peru, the largest tributary basin of the Madeira basin, itself the largest tributary basin of the Amazon. Three laterally extensive, Quaternary-age, terrace tracts are present within the Madre de Dios basin. Analysis of sedimentary facies, present in the modern cut banks and terraced sequences, along with radiocarbon dates on fossil wood and leaf material preserved in the terraced strata, allow reconstruction of the Late Quaternary depositional history of the sedimentary sequences, including determination of the approximate timing of aggradation and downcutting episodes and its relationship to the timing of past climate change in this portion of the Amazon basin and beyond. The Quaternary sediments underlying the terraces most often recorded deposition in a coarse-grained meandering fluvial system. The T3 terrace, the highest terrace, is underlain by the Miocene (?) Ipururi Formation, which is unconformably overlain by the late Miocene-Pleistocene (?) (> 48,000 cal yrs BP) Madre de Dios Formation, a multistory coarse-sandy to gravelly channel and point bar complex. The latter was downcut before 29,850 ± 100 cal yrs BP. This downcut landscape was infilled by meandering fluvial strata characterized by gravelly channel deposits in a sequence dominated by floodplain and lateral accretion deposits. These strata were in turn downcut to form the T2 terrace before 11,970 ± 100 cal yrs BP. A third episode of aggradation resulted in the deposition of a sand-dominated meandering channel complex that infilled the T2 valley and was subsequently downcut after 3780 ± 50 cal yrs BP. This most recent terrace is infilled by the modern fluvial sediment, which has been actively aggrading since at least 870 ± 50 cal yrs BP. Importantly, the Madre de Dios fluvial system actively aggraded between 30,000 and 25,000 cal yrs BP, (and likely

  12. Stage-discharge rating curves based on satellite altimetry and modeled discharge in the Amazon basin

    Science.gov (United States)

    Paris, Adrien; Dias de Paiva, Rodrigo; Santos da Silva, Joecila; Medeiros Moreira, Daniel; Calmant, Stephane; Garambois, Pierre-André; Collischonn, Walter; Bonnet, Marie-Paule; Seyler, Frederique

    2016-05-01

    In this study, rating curves (RCs) were determined by applying satellite altimetry to a poorly gauged basin. This study demonstrates the synergistic application of remote sensing and watershed modeling to capture the dynamics and quantity of flow in the Amazon River Basin, respectively. Three major advancements for estimating basin-scale patterns in river discharge are described. The first advancement is the preservation of the hydrological meanings of the parameters expressed by Manning's equation to obtain a data set containing the elevations of the river beds throughout the basin. The second advancement is the provision of parameter uncertainties and, therefore, the uncertainties in the rated discharge. The third advancement concerns estimating the discharge while considering backwater effects. We analyzed the Amazon Basin using nearly one thousand series that were obtained from ENVISAT and Jason-2 altimetry for more than 100 tributaries. Discharge values and related uncertainties were obtained from the rain-discharge MGB-IPH model. We used a global optimization algorithm based on the Monte Carlo Markov Chain and Bayesian framework to determine the rating curves. The data were randomly allocated into 80% calibration and 20% validation subsets. A comparison with the validation samples produced a Nash-Sutcliffe efficiency (Ens) of 0.68. When the MGB discharge uncertainties were less than 5%, the Ens value increased to 0.81 (mean). A comparison with the in situ discharge resulted in an Ens value of 0.71 for the validation samples (and 0.77 for calibration). The Ens values at the mouths of the rivers that experienced backwater effects significantly improved when the mean monthly slope was included in the RC. Our RCs were not mission-dependent, and the Ens value was preserved when applying ENVISAT rating curves to Jason-2 altimetry at crossovers. The cease-to-flow parameter of our RCs provided a good proxy for determining river bed elevation. This proxy was validated

  13. Karyotype differentiation and cytotaxonomic considerations in species of Serrasalmidae (Characiformes) from the Amazon basin

    OpenAIRE

    Celeste Mutuko Nakayama; Eliana Feldberg; Luiz Antonio Carlos Bertollo

    2012-01-01

    Six species of Serrasalmidae from the central Amazon, representatives of the genera Serrasalmus (S. elongatus, S. maculatus, S. cf. rhombeus, and S. rhombeus), Pygocentrus (P. nattereri), and Colossoma (C. macropomum), were analyzed regarding the distribution of the Ag-NORs, C-positive heterochromatin and 18S and 5S rRNA genes on the chromosomes. All specimens had 2n = 60 chromosomes, except S. cf. rhombeus, with 2n = 58, and C. macropomum with 2n = 54 chromosomes. The Ag-NORs were multiple a...

  14. Space-Time Controls on Carbon Sequestration Over Large-Scale Amazon Basin

    Science.gov (United States)

    Smith, Eric A.; Cooper, Harry J.; Gu, Jiujing; Grose, Andrew; Norman, John; daRocha, Humberto R.; Starr, David O. (Technical Monitor)

    2002-01-01

    A major research focus of the LBA Ecology Program is an assessment of the carbon budget and the carbon sequestering capacity of the large scale forest-pasture system that dominates the Amazonia landscape, and its time-space heterogeneity manifest in carbon fluxes across the large scale Amazon basin ecosystem. Quantification of these processes requires a combination of in situ measurements, remotely sensed measurements from space, and a realistically forced hydrometeorological model coupled to a carbon assimilation model, capable of simulating details within the surface energy and water budgets along with the principle modes of photosynthesis and respiration. Here we describe the results of an investigation concerning the space-time controls of carbon sources and sinks distributed over the large scale Amazon basin. The results are derived from a carbon-water-energy budget retrieval system for the large scale Amazon basin, which uses a coupled carbon assimilation-hydrometeorological model as an integrating system, forced by both in situ meteorological measurements and remotely sensed radiation fluxes and precipitation retrieval retrieved from a combination of GOES, SSM/I, TOMS, and TRMM satellite measurements. Brief discussion concerning validation of (a) retrieved surface radiation fluxes and precipitation based on 30-min averaged surface measurements taken at Ji-Parana in Rondonia and Manaus in Amazonas, and (b) modeled carbon fluxes based on tower CO2 flux measurements taken at Reserva Jaru, Manaus and Fazenda Nossa Senhora. The space-time controls on carbon sequestration are partitioned into sets of factors classified by: (1) above canopy meteorology, (2) incoming surface radiation, (3) precipitation interception, and (4) indigenous stomatal processes varied over the different land covers of pristine rainforest, partially, and fully logged rainforests, and pasture lands. These are the principle meteorological, thermodynamical, hydrological, and biophysical

  15. Succession-inducing disturbances and the old-growth forest mosaic of a Central Amazon landscape

    Science.gov (United States)

    Chambers, J. Q.; Negron Juarez, R. I.; Marra, D.; Roberts, D. A.; Di Vittorio, A. V.; Higuchi, N.; Trumbore, S.

    2011-12-01

    Old-growth forest ecosystems comprise a mosaic of patches in different successional stages, with the fraction of the landscape in any particular state relatively constant over large temporal and spatial scales. Tropical forest studies commonly assume that plots covering only a small fraction of the landscape representatively sample this mosaic, and that departures from steady-state represent trends. Here a critical test of this equilibrium assumption for a Central Amazon old-growth forest landscape is carried out by combining extensive forest field plot data, remote sensing analysis to generate disturbance probability distribution functions, and simulation modeling to place plot-level results into a landscape context. Results show that succession-inducing disturbances had a return frequency of ~100 years, and that these episodic events have been poorly sampled by existing forest sample plots. Overall, key ecosystem attributes of small patches are expected to constantly change in the Central Amazon, and long significant trends can result from purely stochastic processes. The role of episodic disturbances will be discussed in terms of Amazon forest carbon balance, and regional tree diversity patterns.

  16. Loggers and Forest Fragmentation: Behavioral Models of Road Building in the Amazon Basin

    Science.gov (United States)

    Arima, Eugenio Y.; Walker, Robert T.; Perz, Stephen G.; Caldas, Marcellus

    2005-01-01

    Although a large literature now exists on the drivers of tropical deforestation, less is known about its spatial manifestation. This is a critical shortcoming in our knowledge base since the spatial pattern of land-cover change and forest fragmentation, in particular, strongly affect biodiversity. The purpose of this article is to consider emergent patterns of road networks, the initial proximate cause of fragmentation in tropical forest frontiers. Specifically, we address the road-building processes of loggers who are very active in the Amazon landscape. To this end, we develop an explanation of road expansions, using a positive approach combining a theoretical model of economic behavior with geographic information systems (GIs) software in order to mimic the spatial decisions of road builders. We simulate two types of road extensions commonly found in the Amazon basin in a region: showing the fishbone pattern of fragmentation. Although our simulation results are only partially successful, they call attention to the role of multiple agents in the landscape, the importance of legal and institutional constraints on economic behavior, and the power of GIs as a research tool.

  17. 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.

  18. 14C AMS dating of fires in the central Amazon rain forest

    International Nuclear Information System (INIS)

    Soil samples were collected in tierra firme upland and lowland areas of the Km 41 reserve near Manaus (20 deg. 30'S and 60 deg. W), in Central Brazilian Amazon, within a 1700 m transect, at eight different depth ranges, from surface to 100 cm. The highest charcoal concentrations were found at the depth range of 20-50 cm. AMS radiocarbon dating of 31 samples were performed at the ANU. The ages of the charcoals were found to vary within the 130 to 2400 years BP range, mostly between 1200 and 1400 years BP, one of the known Holocene dry periods of the Amazon region. The results show that the fires have regional dimensions and are associated with climate regional changes

  19. New species of Cyphocharax (Characiformes: Curimatidae from the upper rio Negro, Amazon basin

    Directory of Open Access Journals (Sweden)

    Bruno F. Melo

    2014-06-01

    Full Text Available A new species of Cyphocharax, Curimatidae, apparently endemic to the blackwater upper rio Negro of the Amazon basin in northern Brazil, is described.The new species is readily distinguished from its congeners by the presence of a distinctly longitudinally elongate, posteriorly vertically expanding patch of dark pigmentation along the midlateral surface of the caudal peduncle, with the patch extending from the base of the middle caudal-fin rays anteriorly past the vertical through the posterior terminus of the adipose fin. The new species additionally differs from all congeners in details of body and fin pigmentation and meristic and morphometric ratios. Evidence for the assignment of the species to Cyphocharax and the occurrence of other species of the Curimatidae apparently endemic to the upper rio Negro catchment is discussed.

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

    Science.gov (United States)

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

    2016-04-01

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

  1. Formaldehyde and Glyoxal Measurements as Tracers of Oxidation Chemistry in the Amazon Basin

    Science.gov (United States)

    Thayer, M. P.; Dorris, M. R.; Keutsch, F. N.; Springston, S. R.; Jimenez, J. L.; Palm, B. B.; Seco, R.; Kim, S.; Yee, L.; Wernis, R. A.; Goldstein, A. H.; Isaacman-VanWertz, G. A.; Liu, Y.; Martin, S. T.

    2015-12-01

    Formaldehyde (HCHO) and glyoxal (CHOCHO) are important tracers for oxidative processes in the atmosphere such as oxidation of volatile organic compounds (VOCs) and production of HO2 radicals by photolysis or reaction with OH. Products of VOC oxidation and radical cycling, such as aerosols and tropospheric ozone, have direct impacts on human health. During the Green Ocean Amazon campaign (GoAmazon2014/5), HCHO and CHOCHO measurements were obtained together with OH, RO2+HO2, CO, CO2, O3, NOx, (o)VOCs, and aerosol particle size distribution. HCHO concentration was measured by the Madison FIber Laser-Induced Fluorescence (FILIF) instrument, while CHOCHO concentrations were collected by the Madison Laser-Induced Phosphorescence (Mad-LIP) instrument. Here we present data collected during 2014 at the T3 field site, 60 km to the west of Manaus, Brazil (3°12'47.82"S, 60°35'55.32"W). The T3 GoAmazon site varies between sampling strictly pristine (biogenic) emissions and influence from anthropogenic emissions from Manaus, depending on meteorological conditions. Here we present overall trends and regimes observed during the campaign, with a focus on HCHO, CHOCHO, and related species within the context of VOC oxidation and secondary pollutant production. We acknowledge the support from the Central Office of the Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA), the Instituto Nacional de Pesquisas da Amazonia (INPA), and the Universidade do Estado do Amazonia (UEA). The work was conducted under 001030/2012-4 of the Brazilian National Council for Scientific and Technological Development (CNPq). Data were collected from the Atmospheric Radiation Measurement (ARM) Climate Research Facility, a U.S. Department of Energy Office of Science user facility sponsored by the Office of Biological and Environmental Research. Additionally, we acknowledge logistical support from the ARM Climate Research Facility. Additional funding from: NSF GRFP DGE-1256259, and NSF AGS-1051338

  2. Monitoring water level in large trans-boundary ungauged basins with altimetry: the example of ENVISAT over the Amazon basin

    Science.gov (United States)

    Seyler, Frederique; Calmant, Stephane; da Silva, Joecila; Filizola, Naziano; Roux, Emmanuel; Cochonneau, Gerard; Vauchel, Philippe; Bonnet, Marie-Paule

    2009-01-01

    Brasil and Bolivia have water plans projects on the Beni-Madeira river, a major tributary of the Amazon. There are four main tributaries to the Rio Madeira: the Guapore, the Mamore and the Beni rivers into the Bolivian territory, and the Madre de Dios River crossing the North of Bolivia, coming from Peru. Most parts of these rivers are very far from the Andean capital cities of Bolivia and Peru, unreachable for long periods of time. Very few gauging stations are in operation, either for the Bolivian or the Peruvian part, most of them being located at the Andes piedmont or near the confluence at the Brazilian border as they form the Madeira river. This situation is exemplary of large transboundary basins in the tropical part of the world. We have computed 39 water level time series using ENVISAT altimetry data over the four tributaries of the Madeira and the Madeira itself. We present a preliminary study mostly conducted onto the Guapore river, in order to assess the quality of these time series for a variety of situations, but mostly narrow and meandering riverbeds. Comparison between water levels variation in the mainstream and within the inundations plains and lakes are drawn. We conclude by the perspectives offered by the combined use of radar altimetry and SAR imagery for the global monitoring of water resources, in large tropical transboundary basins.

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

    Directory of Open Access Journals (Sweden)

    M. Guimberteau

    2014-01-01

    to a satellite-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.

  4. Global determination of rating curves in the Amazon basin from satellite altimetry

    Science.gov (United States)

    Paris, Adrien; Paiva, Rodrigo C. D.; Santos da Silva, Joecila; Medeiros Moreira, Daniel; Calmant, Stéphane; Collischonn, Walter; Bonnet, Marie-Paule; Seyler, Frédérique

    2014-05-01

    The Amazonian basin is the largest hydrological basin all over the world. Over the past few years, it has experienced an unusual succession of extreme droughts and floods, which origin is still a matter of debate. One of the major issues in understanding such events is to get discharge series distributed over the entire basin. Satellite altimetry can be used to improve our knowledge of the hydrological stream flow conditions in the basin, through rating curves. Rating curves are mathematical relationships between stage and discharge at a given place. The common way to determine the parameters of the relationship is to compute the non-linear regression between the discharge and stage series. In this study, the discharge data was obtained by simulation through the entire basin using the MGB-IPH model with TRMM Merge input rainfall data and assimilation of gage data, run from 1998 to 2009. The stage dataset is made of ~900 altimetry series at ENVISAT and Jason-2 virtual stations, sampling the stages over more than a hundred of rivers in the basin. Altimetry series span between 2002 and 2011. In the present work we present the benefits of using stochastic methods instead of probabilistic ones to determine a dataset of rating curve parameters which are hydrologicaly meaningful throughout the entire Amazon basin. The rating curve parameters have been computed using an optimization technique based on Markov Chain Monte Carlo sampler and Bayesian inference scheme. This technique provides an estimate of the best value for the parameters together with their posterior probability distribution, allowing the determination of a credibility interval for calculated discharge. Also the error over discharges estimates from the MGB-IPH model is included in the rating curve determination. These MGB-IPH errors come from either errors in the discharge derived from the gage readings or errors in the satellite rainfall estimates. The present experiment shows that the stochastic approach

  5. Basin development and petroleum prospects of central New Hebrides arc

    Energy Technology Data Exchange (ETDEWEB)

    Greene, H.G.; Wong, F.L.; Falvey, D.A.; MacFarlane, A.

    1986-07-01

    Two extensive intra-arc basins, the Central basin of Vanuatu and the Vanikolo basin, have recently been mapped in detail and appear to have developed in the last 3 m.y. primarily from subduction and arc-polarity reversal. The Central basin of Vanuatu is being modified by the ridge-arc collision and is still accumulating sediment, whereas the Vanikolo basin has no physiographic expression and is completely filled with sediment. Quaternary volcanism has separated the Central basin of Vanuatu into two physiographic basins (North Aoba and South Aoba basins). The Central basin is flanked on the west by five smaller insular basins associated with the islands of Malakula and Espiritu Santo. Although North and South Aoba basins lie in water depths as great as 3 km, migration paths into the shallower water basins appear to be present, and structures that could trap hydrocarbons occur. More than 5 km of sediment of Miocene and younger age were deposited in the deeper basins, whereas 2-km thick sediments of late Miocene and younger age occur near the islands. The most promising hydrocarbon basin is Malakula basin, which lies on the eastern shelf of Malakula Island, where onshore source rock analyses indicated potential gas concentrations. North of the Central basin of Vanuatu lies the largest basin in the region, the Vanikolo basin, covering more than 14,000 km/sup 2/ and containing more than 6 km of probablen Miocene and younger sediment. Water depths are more than 2 km in the deepest part of this basin, but much of the margins lie in water less than 1 km deep. Structures along the margins could trap hydrocarbons, especially along the western side, and are accessible to drilling. More work must be done in Vanikolo basin to assess hydrocarbon source rocks, migration, and heat flow before a comprehensive hydrocarbon evaluation can be made.

  6. Ferromanganese nodules from the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Jauhari, P.; Pattan, J.N.

    In order to delineate a mine site for ferromanganese nodules, extensive surveys were conducted in Central Indian Ocean Basin. Mapping of the basin by multibeam swath bathymetry (Hydrosweep) has revealed many new bottom relief features...

  7. The nitrogen budget for different forest types in the central Congo Basin

    Science.gov (United States)

    Bauters, Marijn; Verbeeck, Hans; Cizungu, Landry; Boeckx, Pascal

    2016-04-01

    Characterization of fundamental processes in different forest types is vital to understand the interaction of forests with their changing environment. Recent data analyses, as well as modeling activities have shown that the CO2 uptake by terrestrial ecosystems strongly depends on site fertility, i.e. nutrient availability. Accurate projections of future net forest growth and terrestrial CO2 uptake thus necessitate an improved understanding on nutrient cycles and how these are coupled to the carbon (C) cycle in forests. This holds especially for tropical forests, since they represent about 40-50% of the total carbon that is stored in terrestrial vegetation, with the Amazon basin and the Congo basin being the largest two contiguous blocks. However, due to political instability and reduced accessibility in the central Africa region, there is a strong bias in scientific research towards the Amazon basin. Consequently, central African forests are poorly characterized and their role in global change interactions shows distinct knowledge gaps, which is important bottleneck for all efforts to further optimize Earth system models explicitly including this region. Research in the Congo Basin region should combine assessments of both carbon stocks and the underlying nutrient cycles which directly impact the forest productivity. We set up a monitoring network for carbon stocks and nitrogen fluxes in four different forest types in the Congo Basin, which is now operative. With the preliminary data, we can get a glimpse of the differences in nitrogen budget and biogeochemistry of African mixed lowland rainforest, monodominant lowland forest, mixed montane forest and eucalypt plantations.

  8. Water discharge estimates from large radar altimetry datasets in the Amazon basin

    Directory of Open Access Journals (Sweden)

    A. C. V. Getirana

    2012-06-01

    Full Text Available In this study, we evaluate the use of a large radar altimetry dataset as a complementary gauging network capable of providing water discharge in ungauged regions within the Amazon basin. A rating-curve-based methodology is adopted to derive water discharge from altimetric data provided by Envisat at 444 virtual stations (VS. The stage-discharge relations at VS are built based on radar altimetry and outputs from a global flow routing scheme. In order to quantify the impact of modeling uncertainties on rating-curve based discharges, another experiment is performed using simulated discharges derived from a simplified data assimilation procedure. Discharge estimates at 90 VS are evaluated against observations during the curve fitting calibration (2002–2005 and evaluation (2006–2008 periods, resulting in mean relative RMS errors as high as 52% and 12% for experiments without and with assimilation, respectively. Without data assimilation, uncertainty of discharge estimates can be mostly attributed to forcing errors at smaller scales, generating a positive correlation between performance and drainage area. Mean relative errors (RE of altimetry-based discharges varied from 15% to 92% for large and small drainage areas, respectively. Rating curves produced a mean RE of 54% versus 68% from model outputs. Assimilating discharge data decreases the mean RE from 68% to 12%. These results demonstrate the feasibility of applying the proposed methodology to the regional or global scales. Also, it is shown the potential of satellite altimetry for predicting water discharge in poorly-gauged and ungauged river basins.

  9. Study of ceramics from circular archaeological sites of Amazonic Basin by geochemical methods: dating and characterization

    International Nuclear Information System (INIS)

    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)

  10. Characterization, analysis and dating of archaeological ceramics from the Amazon basin through nuclear techniques

    International Nuclear Information System (INIS)

    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)

  11. Trace elements in aerosols from background air pollution monitoring stations in the Amazon Basin using nuclear-related techniques

    International Nuclear Information System (INIS)

    In order to study the natural release of aerosol particles by the Amazon Basin tropical rain forest, the composition and size distribution of biogenic aerosol particles were analyzed. The role of the atmospheric emissions from the Amazon Basin rain forest in the global atmosphere will be investigated. The atmosphere was studied in long-term sampling stations in three different locations. The elemental composition of aerosol particles released during biomass burning was also measured in several different ecosystems, from primary forest to Savannah. One of the main focuses was to identify and quantify important physical and chemical processes in the generation, transformation and deposition of aerosol particles. Also important was to obtain a better understanding of natural aerosol sources concerning identification, their characteristics and strength, to be able to understand the natural chemistry in the atmosphere on a global scale. 36 refs, 3 figs, 3 tabs

  12. Palm oil production in Peruvian Amazon Basin. A case study of current effects and emerging localized alternatives in Loreto district

    OpenAIRE

    Jensen, Charlotte Bratberget

    2015-01-01

    An analysis of palm oil production in the Peruvian Amazon basin was carried out in a systemic way, as part of a whole, with its complexities. With an agroecological perspective, the social, ecological and economic effects of this production are discussed. Additionally, alternatives that could better fulfil the necessities of farmers were explored. The oil palm, Elaeis guineensis, originally from West Africa, is a common plant in an enormous industry that is extensive in South East Asia, ma...

  13. Transport of Saharan dust from the Bodélé Depression to the Amazon Basin: a case study

    Directory of Open Access Journals (Sweden)

    Y. Ben-Ami

    2010-02-01

    Full Text Available Through long-range transport of dust, the Sahara desert supplies essential minerals to the Amazon rain forest. Since Saharan 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, 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 marine 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.

  14. 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.

  15. Phorcotabanus cinereus (Wiedemann, 1821 (Diptera, Tabanidae, an ornithophilic species of Tabanid in Central Amazon, Brazil

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    Limeira-de-Oliveira Francisco

    2002-01-01

    Full Text Available In Central Amazon, Brazil, the tabanid Phorcotabanus cinereus (Wiedemann was recorded attacking the native duck Cairina moschata (Linnaeus (Anseriformes, Anatidae. The flight and behavior of the tabanid during the attacks and the host's defenses were videotaped and analyzed in slow motion. The tabanid was recorded flying rapidly around the heads of the ducks before landing. Landing always took place on the beak, and then the tabanid walked to the fleshy caruncle on the basal part of the beak to bite and feed. Firstly the duck defends itself through lateral harsh head movements, and then, when it is being bitten, it defends itself by rubbing its head on the body, or dipping the head into water, when swimming. If disturbed, the fly resumed the same pattern of flight as before and would generally try to land again on the same host and bite in the same place. This feeding activity was observed predominantly between 9:30 am and 4:30 pm and always in open areas, near aquatic environments, from June 1996 to January 1997, the dry season in Central Amazon. To test the attractiveness of other animals to P. cinereus, mammals, caimans and domestic and wild birds were placed in suitable habitat and the response of P. cinereus observed. P. cinereus did not attack these animals, suggesting that this species has a preference for ducks, which are plentiful in the region.

  16. Are rapids a barrier for floodplain fishes of the Amazon basin ? A demographic study of the keystone floodplain species Colossoma macropomum (Teleostei: Characiformes)

    OpenAIRE

    Farias, I. P.; Torrico, J. P.; Garcia-Davila, C.; Santos, M. D. F.; T. Hrbek; Renno, Jean-François

    2010-01-01

    We investigated demographic history and population structuring of Colossoma macropomum sampled from 14 localities in the Amazon basin and the Bolivian sub-basin; the two basins are separated by a series of 16 rapids. Although genetically differentiated, IMa analyses suggest non-zero bi-directional migration rates, and inter-basin divergence of approximately 17 thousand years ago. Analyses in BEAST indicated that Bolivian C. macropomum has been demographically stable except for a moderate popu...

  17. Controls on Variations of Surface Energy, Water, and Carbon Budgets within Large-Scale Amazon Basin

    Science.gov (United States)

    Smith, Eric A.; Cooper, Harry J.; Grose, Andrew; Gu, Jiu-Jing; Norman, John; daRocha, Humberto R.; Dias, Pedro Silva

    2002-01-01

    A key research focus of the LBA Research Program is understanding the space-time variations in interlinked surface energy, water, and carbon budgets, the controls on these variations, and the implications of these controls on the carbon sequestering capacity of the large scale forest-pasture system that dominates the Amaz6nia landscape. Quantification of these variations and controls are investigated by a combination of in situ measurements, remotely sensed measurements from space, and a realistically forced hydrometeorological model coupled to a carbon assimilation model, capable of simulating details within the surface energy and water budgets along with the principle processes of photosynthesis and respiration. Herein we describe the results of an investigation concerning the space-time controls of carbon sources and sinks distributed over the large scale Amazon basin. The results are derived from a carbon-water-energy budget retrieval system for the large scale Amazon basin, which uses a coupled carbon assimilation-hydrometeorological model as an integrating system, forced by both in situ meteorological measurements and remotely sensed radiation and precipitation fluxes obtained from a combination of GOES, SSM/I, TOMS, and TRh4M satellite measurements. Results include validation of (a) retrieved surface radiation and precipitation fluxes based on 30-min averaged surface measurements taken at Ji-Parani in Rondania and Manaus in Amazonas, and (b) modeled sensible, latent, and C02 fluxes based on tower measurements taken at Reserva Jaru, Manaus and Fazenda Nossa Senhora. The space-time controls on carbon sequestration are partitioned into sets of factors classified by: (1) above canopy meteorology, (2) incoming surface radiation, (3) precipitation interception, and (4) indigenous stomatal processes varied over the different land covers of pristine rainforest, partially, and fully logged rainforests, and pasture lands. These are the principle meteorological

  18. Detailed bathymetric surveys in the central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Kodagali, V.N.; KameshRaju, K.A.; Ramprasad, T.; George, P.; Jaisankar, S.

    Over 420,000 line kilometers of echo-sounding data was collected in the Central Indian Basin. This data was digitized, merged with navigation data and a detailed bathymetric map of the Basin was prepared. The Basin can be broadly classified...

  19. Seroprevalence of Toxoplasma gondii in free-living amazon river dolphins (Inia geoffrensis) from central Amazon, Brazil

    Science.gov (United States)

    Toxoplasma gondii is an important pathogen in aquatic mammals and its presence in these animals may indicate water contamination of aquatic environment by oocysts. Serum samples from 95 dolphins from free-living Amazon River dolphins (Inia geoffrensis) from Sustainable Development Reserve Mamirauá (...

  20. Detection of long-term trends in monthly hydro-climatic records of Colombia and the Amazon River basin through Empirical Mode Decomposition

    Science.gov (United States)

    Carmona, A. M.; Poveda, G.

    2011-12-01

    We search for long-term trends in 25- to 50-year records of monthly rainfall (100 stations), average river discharges (42 stations), and mean and minimum air temperature records (37 stations) in Colombia, as well as monthly records in 29 rain gauges within the Amazon River basin. Time series of average monthly river discharges are selected from 10 Colombian river basins with gauging stations located downstream along the main channel. The Empirical Mode Decomposition (EMD) method is used as a filtering process to decompose a given time series into a finite number of intrinsic mode functions (IMF), assuming that diverse simple oscillatory modes of different frequencies coexist in the series, and that the residual captures the long-term trend of the record. The Mann-Kendall test for autocorrelated data is used to assess the statistical significance of the trends, and the Sen test is used for the magnitude of the trends. Results show that 62% of monthly river discharge series exhibit decreasing trends between 0.01-1.92 m3/s yr-1. The identified trends are strongly consistent downstream, albeit with contrasting results for the ratios between the magnitude of the trend and mean discharges. Most minimum temperature series (87%) show increasing trends [0.01-0.08°C yr-1]. Results on precipitation are inconclusive as monthly records exhibit a mixed pattern of increasing (41%, between 0.1-7.0 mm yr-1) and decreasing (44%, between 0.1-7.4 mm yr-1) trends, except for the Pacific region, which shows clear-cut positive trends, consistently with an increasing trend identified in the strength of the Chocó low-level jet winds over the Pacific coast of Colombia, the main moisture advection mechanism into the region. Maximum trend magnitudes in precipitation records on the Amazon basin were found to be decreasing (53%, between 0.04 -9.1 mm yr-1), mostly around the basin's central and south-eastern regions. The highest decreasing trend magnitude in the Amazon was found to be -9.1mm

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

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    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.

  2. Using GRACE Total Water Storage Changes to constrain River Routing Models in the Amazon River basin

    Science.gov (United States)

    de Linage, C.; Lo, M.; Famiglietti, J. S.; Ray, R. L.; Beighley, R. E.

    2010-12-01

    The GRACE mission provides monthly to 10-day maps of Total Water Storage Anomalies corresponding to the vertically integrated land water storage (soil moisture and groundwater) as well as storage in river channels and floodplains (surface waters). The surface water component is an important contributor to total water storage in the Amazon River basin as shown by improved agreement between GRACE observations and model simulations when runoff is routed through the river network as compared to no river routing. We use the Community Land Model version 3.5 to model land water storage along with runoff by accounting for a simple ground water model. Surface and subsurface runoff predictions are then routed using two different routing models: a simple cell-to-cell routing scheme (e.g. Branstetter and Famiglietti, 1999) and the Hillslope River Routing (Beighley et al. 2010). We evaluate model performances against the spatio-temporal variations of GRACE data by carrying out a Singular Value Decomposition of the cross-covariance matrix. We also compare the two models in the light of their respective intrinsic capabilities. We finally investigate the impact of the precipitation data on model outputs by using TRMM products instead of GLDAS (CMAP) products.

  3. Widespread Amazon forest tree mortality from a single cross-basin squall line event

    Science.gov (United States)

    Negrón-Juárez, Robinson I.; Chambers, Jeffrey Q.; Guimaraes, Giuliano; Zeng, Hongcheng; Raupp, Carlos F. M.; Marra, Daniel M.; Ribeiro, Gabriel H. P. M.; Saatchi, Sassan S.; Nelson, Bruce W.; Higuchi, Niro

    2010-08-01

    Climate change is expected to increase the intensity of extreme precipitation events in Amazonia that in turn might produce more forest blowdowns associated with convective storms. Yet quantitative tree mortality associated with convective storms has never been reported across Amazonia, representing an important additional source of carbon to the atmosphere. Here we demonstrate that a single squall line (aligned cluster of convective storm cells) propagating across Amazonia in January, 2005, caused widespread forest tree mortality and may have contributed to the elevated mortality observed that year. Forest plot data demonstrated that the same year represented the second highest mortality rate over a 15-year annual monitoring interval. Over the Manaus region, disturbed forest patches generated by the squall followed a power-law distribution (scaling exponent α = 1.48) and produced a mortality of 0.3-0.5 million trees, equivalent to 30% of the observed annual deforestation reported in 2005 over the same area. Basin-wide, potential tree mortality from this one event was estimated at 542 ± 121 million trees, equivalent to 23% of the mean annual biomass accumulation estimated for these forests. Our results highlight the vulnerability of Amazon trees to wind-driven mortality associated with convective storms. Storm intensity is expected to increase with a warming climate, which would result in additional tree mortality and carbon release to the atmosphere, with the potential to further warm the climate system.

  4. Recent shift from forest to savanna burning in the Amazon Basin observed by satellite

    International Nuclear Information System (INIS)

    The numbers of fires detected on forest, savanna and transition lands during the 2002–10 biomass burning seasons in Amazonia are shown using fire count data and co-located land cover classifications from the Moderate Resolution Imaging Spectroradiometer (MODIS). The ratio of forest fires to savanna fires has varied substantially over the study period, with a maximum ratio of 0.65:1 in 2005 and a minimum ratio of 0.27:1 in 2009, with the four lowest years occurring in 2007–10. The burning during the droughts of 2007 and 2010 is attributed to a higher number of savanna fires relative to the drought of 2005. A decrease in the regional mean single scattering albedo of biomass burning aerosols, consistent with the shift from forest to savanna burning, is also shown. During the severe drought of 2010, forest fire detections were lower in many areas compared with 2005, even though the drought was more severe in 2010. This result suggests that improved fire management practices, including stricter burning regulations as well as lower deforestation burning, may have reduced forest fires in 2010 relative to 2005 in some areas of the Amazon Basin. (letter)

  5. Abiotic variability among different aquatic systems of the central Amazon floodplain during drought and flood events.

    Science.gov (United States)

    Affonso, A G; Queiroz, H L; Novo, E M L M

    2015-11-01

    This paper examines water properties from lakes, (depression lakes, sensu Junk et al., 2012), channels (scroll lakes with high connectivity, sensu Junk et al., 2012) and paleo-channels (scroll lakes with low connectivity-sensu Junk et al., 2012, locally called ressacas) located in Mamirauá Sustainable Development Reserve, in Central Amazon floodplain, Amazonas, Brazil. We analysed surface temperature, conductivity, pH, dissolved oxygen, turbidity, transparency, suspended inorganic and organic matter, chlorophyll-a, pheophytin, total nitrogen, total phosphorus, organic and inorganic carbon in 2009 high water phase, 2009 and 2010 low water phases. Multivariate statistical analyses of 24 aquatic systems (6 ressacas, 12 lakes and 6 channels, 142 samples) were applied to the variables in order to: 1) quantify differences among aquatic system types; 2) assess how those differences are affected in the different phases of the hydrological year. First, we analysed the entire set of variables to test for differences among phases of the hydrological year and types of aquatic systems using a PERMANOVA two-way crossed design. The results showed that the all measured limnological variables are distinct regarding both factors: types of aquatic systems and hydrological phases. In general, the magnitude and amplitude of all variables were higher in the low water phase than in the high water phase, except for water transparency in all aquatic system's types. PERMANOVA showed that the differences between aquatic system's types and hydrological phases of all variables were highly significant for both main factors (type and phase) and for the type x phase interaction. Limnological patterns of Amazon floodplain aquatic systems are highly dynamic, dependent on the surrounding environment, flood pulse, main river input and system type. These patterns show how undisturbed systems respond to natural variability in such a diverse environment, and how distinct are those aquatic systems

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

    Directory of Open Access Journals (Sweden)

    C. A. Quesada

    2012-06-01

    Full Text Available 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

  7. Surface freshwater storage and variability in the Amazon basin from multi-satellite observations, 1993-2007

    Science.gov (United States)

    Papa, Fabrice; Frappart, Frederic; Güntner, Andreas; Prigent, Catherine; Aires, Filipe; Getirana, Augusto C. V.; Maurer, Raffael

    2013-11-01

    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 spatiotemporal 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 ~1200 km3 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 floodplains of the Amazon basin was, respectively, ~230 (~40%) and 210 (~50%) km3 below the 1993-2007 average. This new 15 year 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.

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

    Science.gov (United States)

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

    2014-05-01

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

  11. Sr and Nd isotopes of suspended sediments from rivers of the Amazon basin

    Science.gov (United States)

    Hatting, Karina; Santos, Roberto V.; Sondag, Francis

    2014-05-01

    The Rb-Sr and Sm-Nd isotopic systems are important tools to constrain the provenance of sediment load in river systems. This study presents the isotopic composition of Sr and Nd isotopes and major and minor elements in suspended sediments from the Marañón-Solimões, Amazonas and Beni-Madeira rivers. The data were used to constrain the source region of the sediments and to better understand the main seasonal and spatial transport processes within the basin based on the variations of the chemical and isotopic signals. They also allow establishing a relationship between sediment concentrations and flow rate values. The study presents data collected during a hydrological year between 2009 and 2010. The Marañón-Solimões River presents low Sr isotopic values (0.7090-0.7186), broad EpslonNd(0) range (-15.17 to -8.09) and Nd model (TDM) ages varying from 0.99 to 1.81 Ga. Sources of sediments to the Marañón-Solimões River include recent volcanic rocks in northern Peru and Ecuador, as well as rocks with long crustal residence time and carbonates from the Marañón Basin, Peru. The Beni-Madeira River has more radiogenic Sr isotope values (0.7255-0.7403), more negative EpslonNd(0) values (-20.46 to -10.47), and older Nd isotope model ages (from 1.40 to 2.35 Ga) when compared to the Marañón-Solimões River. These isotope data were related to the erosion of Paleozoic and Cenozoic foreland basins that are filled with Precambrian sediments derived from the Amazonian Craton. These basins are located in Bolivian Subandina Zone. The Amazon River presents intermediate isotopic values when compared to those found in the Marañón-Solimões and Beni-Madeira rivers. Its Sr isotope ratios range between 0.7193 and 0.7290, and its EpslonNd(0) values varies between -11.09 and -9.51. The Nd isotope model ages of the suspended sediments vary between 1.28 and 1.77 Ga. Concentrations of soluble and insoluble elements indicate a more intense weathering activity in sediments of the Beni

  12. Karyological analysis of Proechimys cuvieri and Proechimys guyannensis (Rodentia, Echimyidae from central Amazon

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Faresin e Silva

    2012-01-01

    Full Text Available The aim was to characterize the karyotype of rodents of the genus Proechimys from three localities in the central Brazilian Amazon, in the search for new markers that might shed light on our understanding of the taxonomy and evolutionary history of this taxon. Two karyotypes were found, viz., 2n = 28, FN = 46 in individuals from the NRSP (Cuieiras River and REMAN (Manaus, and 2n = 46, FN = 50 in individuals from the Balbina Hydroelectric Plant. While individuals with the karyotype with 2n = 28 chromosomes were morphologically associated with Proechimys cuvieri, their karyotype shared similarities with those of the same diploid number in two other regions. Although three karyotypes are described for Proechimys cuvieri, no geographic distribution pattern that defined a cline could be identified. Based on the morphological examination of voucher specimens and additional results from molecular analysis, the karyotype with 2n = 46 and FN = 50 could be associated with P. guyannensis.

  13. Modeling Potential Impacts of Planting Palms or Tree in Small Holder Fruit Plantations on Ecohydrological Processes in the Central Amazon

    Directory of Open Access Journals (Sweden)

    Norbert Kunert

    2015-07-01

    Full Text Available Native fruiting plants are widely cultivated in the Amazon, but little information on their water use characteristics can be found in the literature. To explore the potential impacts of plantations on local to regional water balance, we studied plant water use characteristics of two native fruit plants commonly occurring in the Amazon region. The study was conducted in a mixed fruit plantation containing a dicot tree species (Cupuaçu, Theobroma grandiflorum and a monocot palm species (Açai, Euterpe oleracea close to the city of Manaus, in the Central Amazon. Scaling from sap flux measurements, palms had a 3.5-fold higher water consumption compared to trees with a similar diameter. Despite the high transpiration rates of the palms, our plantation had only one third of the potential water recycling capacity of natural forests in the area. Converting natural forest into such plantations will thus result in significantly higher runoff rates.

  14. 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

  15. Predicting biomass of hyperdiverse and structurally complex Central Amazon forests - a virtual approach using extensive field data

    Science.gov (United States)

    Magnabosco Marra, D.; Higuchi, N.; Trumbore, S. E.; Ribeiro, G. H. P. M.; dos Santos, J.; Carneiro, V. M. C.; Lima, A. J. N.; Chambers, J. Q.; Negrón-Juárez, R. I.; Holzwarth, F.; Reu, B.; Wirth, C.

    2015-09-01

    Old-growth forests are subject to substantial changes in structure and species composition due to the intensification of human activities, gradual climate change and extreme weather events. Trees store ca. 90 % of the total AGB above-ground biomass in tropical forests and AGB estimation models are crucial for forest management and conservation. In the Central Amazon, predicting AGB at large spatial-scales is a challenging task due to the heterogeneity of successional stages, high tree species diversity and inherent variations in allometry and architecture. We parameterized generic AGB estimation models applicable across species and a wide range of structural and compositional variation related to species sorting into height layers as well as frequent natural disturbances. We used 727 trees from 101 genera and at least 135 species harvested in a contiguous forest near Manaus, Brazil. Sampling from this dataset we assembled six scenarios designed to span existing gradients in floristic composition and size distribution in order to select models that best predict AGB at the landscape-level across successional gradients. We found that good individual tree model fits do not necessarily translate into good predictions of AGB at the landscape level. When predicting AGB (dry mass) over scenarios using our different models and an available pantropical model, we observed systematic biases ranging from -31 % (pantropical) to +39 %, with RMSE root-mean-square error values of up to 130 Mg ha-1 (pantropical). Our first and second best models had both low mean biases (0.8 and 3.9 %, respectively) and RMSE (9.4 and 18.6 Mg ha-1) when applied over scenarios. Predicting biomass correctly at the landscape-level in complex tropical forests, especially allowing good performance at the margins of data availability for model parametrization, requires the inclusion of predictors related to species architecture. The model of interest should comprise the floristic composition and size

  16. Consequence of forest-to-pasture conversion on CH4 fluxes in the Brazilian Amazon Basin

    Science.gov (United States)

    Steudler, Paul A.; Melillo, Jerry M.; Feigl, Brigitte J.; Neill, Christopher; Piccolo, Marisa C.; Cerri, Carlos C.

    1996-08-01

    Methane (CH4) fluxes between soils and the atmosphere were measured in two tropical forest-to-pasture chronosequences in the state of Rondônia, Brazil. Forest soils always consumed atmospheric CH4 with maximum uptake rates in the dry season. Pasture soils consumed atmospheric CH4 during the dry season, but at lower rates than those in the forests. When soil moisture increased in the pasture soils, they became a source of CH4 to the atmosphere. Integrated over the year, forest soils were a net sink of approximately 470 mg CH4-C/m2, while pastures were a net source of about 270 mg CH4-C/m2. Thus forest-to-pasture conversion resulted in a net source of CH4 from the soil of about 1 g CH4/m2/yr. The total pasture-related CH4 release for the entire Brazilian Amazon increased from 0.8 Tg CH4 in 1970 to about 2.5 Tg CH4 in 1990, with a maximum of 3.1 Tg CH4/yr in 1988. Soils accounted for a small part (about 5%) of the total CH4 release from the basin, while biomass burning and cattle emissions accounted for 95%. The average rate of increase in CH4 emission from pastures was about 0.2 Tg CH4/yr between 1975 and 1988. This represents between 12% and 14% of the global average rate of change in tropospheric CH4 content for this time period.

  17. Elemental composition of aerosol particles from two atmospheric monitoring stations in the Amazon Basin

    International Nuclear Information System (INIS)

    One key region for the study of processes that are changing the composition of the global atmosphere is the Amazon Basin tropical rain forest. The high rate of deforestation and biomass burning is emitting large amounts of gases and fine-mode aerosol particles to the global atmosphere. Two background monitoring stations are operating continuously measuring aerosol composition, at Cuiaba, and Serra do Navio. Fine- and coarse-mode aerosol particles are being collected using stacked filter units. Particle induced X-ray emission (PIXE) was used to measure concentrations of up to 21 elements: Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr, Zr, and Pb. The elemental composition was measured at the new PIXE facility from the University of Sao Paulo, using a dedicated 5SDH tandem Pelletron nuclear accelerator. Absolute principal factor analysis (APFA) has derived absolute elemental source profiles. At the Serra do Navio sampling site a very clean background aerosol is being observed. Biogenic aerosol dominates the fine-mode mass concentration, with the presence of K, P, S, Cl, Zn, Br, and FPM. Three components dominate the aerosol composition: Soil dust particles, the natural biogenic release by the forest, and a marine aerosol component. At the Cuiaba site, during the dry season, a strong component of biomass burning is observed. An aerosol mass concentration up to 120 μg/m3 was measured. APFA showed three components: Soil dust (Al, Ca, Ti, Mn, Fe), biomass burning (soot, FPM, K, Cl) and natural biogenic particles (K, S, Ca, Mn, Zn). The fine-mode biogenic component of both sites shows remarkable similarities, although the two sampling sites are 3000 km apart. Several essential plant nutrients like P, K, S, Ca, Ni and others are transported in the atmosphere as a result of biomass burning processes. (orig.)

  18. Isotopic composition of precipitations in Brazil: isothermic models and the influence of evapotranspiration in the Amazonic Basin

    International Nuclear Information System (INIS)

    The simplest theoretical models of the isotopic fractionation of water during equilibrium isothermical processes are analized in detail. The theoretical results are applied to the interpretation of the stable isotope concentrations in the precipitations of 11 Brazilian cities that belong to the international network of IAEA/WMO. The analysis shows that the experimental data are fairly consistent with such equilibrium models; no non-equilibrium processes need to be assumed. The study of the stable isotope content of precipitations in the Amazonic Basin suggests some modifications to the models in order that the evapotranspiration contribution to the vapour balance be taken into account

  19. Preliminary Measurements Of N2O Partial Pressures In Rivers of Amazon Basin, Brazil

    Science.gov (United States)

    Oliveira, C. B.; Rasera, M. F.; Krusche, A. V.; Victoria, R. L.; Richey, J. E.; Cunha, H. B.; Gomes, B. M.

    2006-12-01

    The concentrations of nitrous oxide (N2O), an important component of the greenhouse effect and with a long residence time in the atmosphere, have significantly increased in this century. The reasons for this atmospheric increase in N2O are still partially unexplained. This uncertainty is worse in relation to aquatic environments. Here we report on preliminary measurements of N2O partial pressures in rivers of the Amazon basin. The study areas are in the state of Rondonia (rivers Ji Parana, Urupa, Comemoracao and Pimenta Bueno) and Amazonas (rivers Solimoes and Negro). The rivers were sampled from October 2005 to April 2006, using with immersion pumps, lowered in the middle of the channel to 60% of total depth. Water was pumped directly into a 1 l plastic bottle, which was overflown three times before closing. Using syringes, 60 ml of N2 were injected into the bottle, simultaenously to the withdrawn of 60 ml of sample. N2O was extracted into these 60 ml of N2 by shaking vigorously for 2 minutes. With the same syringes, the gas was taken from the bottles and injected into sealed evacuated 25 ml vials. Atmospheric samples were taken from one meter above the water column and stored the same way. N2O partial pressures were determined on a Shimadzu GC-14 Green House Gas Analyzer. All rivers showed little variations in N2O partial pressures. Average values in the rivers of Rondonia were around 0.41 ± 0.07 μ atm (n=46), whereas the Solimoes and Negro rivers, in the state of Amazonas, showed values around 0.43 ± 0.08 μ atm (n=131). Atmospheric averages were approximately 0.34 ± 0.04 μ atm (n=58) and 0.32 ± 0.03 μ atm (n=134) in the states of Rondonia and Amazonas, respectively. This means that, although these waters are supersatured in CO2, making evasive fluxes of this gas an important component of the C cycle in this basin, the same does not occur in the N cycle. Small differences in partial pressures of N2O between water and air will result in small fluxes of

  20. An evaluation eMergetics of Itacoatiara's city in the central Amazon, their plywood, and cultivated plain of basin of Madeira's river; Uma avaliacao eMergetica da cidade de Itacoatiara na Amazonia Central, sua industria de compensado e laminado e a varzea da bacia do rio Madeira

    Energy Technology Data Exchange (ETDEWEB)

    Comar, Vito

    1994-12-01

    The plywood production system of Itacoatiara's industry and the wooden extraction impact of cultivated plain of basin of Madeira's river are presented. The incorporated energy flows - eMergy are evaluated by the models mathematical simulation, which applies to specific indices derivation aiming at the comparison with other similar processes. Itacoatiara's city was going analyzed regarding the industry load energetics and of others urban components.

  1. Methane emissions from floodplains in the Amazon Basin: challenges in developing a process-based model for global applications

    Science.gov (United States)

    Ringeval, B.; Houweling, S.; van Bodegom, P. M.; Spahni, R.; van Beek, R.; Joos, F.; Röckmann, T.

    2014-03-01

    Tropical wetlands are estimated to represent about 50% of the natural wetland methane (CH4) emissions and explain a large fraction of the observed CH4 variability on timescales ranging from glacial-interglacial cycles to the currently observed year-to-year variability. Despite their importance, however, tropical wetlands are poorly represented in global models aiming to predict global CH4 emissions. This publication documents a first step in the development of a process-based model of CH4 emissions from tropical floodplains for global applications. For this purpose, the LPX-Bern Dynamic Global Vegetation Model (LPX hereafter) was slightly modified to represent floodplain hydrology, vegetation and associated CH4 emissions. The extent of tropical floodplains was prescribed using output from the spatially explicit hydrology model PCR-GLOBWB. We introduced new plant functional types (PFTs) that explicitly represent floodplain vegetation. The PFT parameterizations were evaluated against available remote-sensing data sets (GLC2000 land cover and MODIS Net Primary Productivity). Simulated CH4 flux densities were evaluated against field observations and regional flux inventories. Simulated CH4 emissions at Amazon Basin scale were compared to model simulations performed in the WETCHIMP intercomparison project. We found that LPX reproduces the average magnitude of observed net CH4 flux densities for the Amazon Basin. However, the model does not reproduce the variability between sites or between years within a site. Unfortunately, site information is too limited to attest or disprove some model features. At the Amazon Basin scale, our results underline the large uncertainty in the magnitude of wetland CH4 emissions. Sensitivity analyses gave insights into the main drivers of floodplain CH4 emission and their associated uncertainties. In particular, uncertainties in floodplain extent (i.e., difference between GLC2000 and PCR-GLOBWB output) modulate the simulated emissions by a

  2. Seasonality and interannual variability of CH4 fluxes from the eastern Amazon Basin inferred from atmospheric mole fraction profiles

    Science.gov (United States)

    Basso, Luana S.; Gatti, Luciana V.; Gloor, Manuel; Miller, John B.; Domingues, Lucas G.; Correia, Caio S. C.; Borges, Viviane F.

    2016-01-01

    The Amazon Basin is an important region for global CH4 emissions. It hosts the largest area of humid tropical forests, and around 20% of this area is seasonally flooded. In a warming climate it is possible that CH4 emissions from the Amazon will increase both as a result of increased temperatures and precipitation. To examine if there are indications of first signs of such changes we present here a 13 year (2000-2013) record of regularly measured vertical CH4 mole fraction profiles above the eastern Brazilian Amazon, sensitive to fluxes from the region upwind of Santarém (SAN), between SAN and the Atlantic coast. Using a simple mass balance approach, we find substantial CH4 emissions with an annual average flux of 52.8 ± 6.8 mg CH4 m-2 d-1 over an area of approximately 1 × 106 km2. Fluxes are highest in two periods of the year: in the beginning of the wet season and during the dry season. Using a CO:CH4 emission factor estimated from the profile data, we estimated a contribution of biomass burning of around 15% to the total flux in the dry season, indicating that biogenic emissions dominate the CH4 flux. This 13 year record shows that CH4 emissions upwind of SAN varied over the years, with highest emissions in 2008 (around 25% higher than in 2007), mainly during the wet season, representing 19% of the observed global increase in this year.

  3. The Role of Lakes and Rivers as Sources of Evaporated Water to the Atmosphere in the Amazon Basin

    International Nuclear Information System (INIS)

    Due its magnitude, the water cycle in the Amazon basin plays a key role in the biogeochemical cycles of the region, as well as affecting regional and global climate. Despite its importance, the Amazon region is under constant pressure because of its natural resources, and deforestation accounts for a major part of this human influence. The continental freshwater system in the region is not highly threatened, although human occupation follows roads and rivers pathways. Several urban and agricultural activities take place by the river's banks. Over the past 30 years, riparian regions have been cleared for agriculture and human settlements, and the floodplains are being intensely used for cattle grazing during the low water season and for fishing during high water, putting at risk highly diverse and abundant fisheries stocks in the region as whole. The floodplains are an important spawning habitat for several species. Thus understanding of biogeochemical and nutrient dynamic of the floodplains is crucial to sustain the ecological health of those systems. Identification of physical process patterns (i.e, evaporation, wind, water current) and sources of water to the floodplains are key to this knowledge. The main objective of this work was to investigate the role of the Amazon floodplains lakes and rivers as sources of evaporated water to the atmosphere. (author)

  4. New occurrences of Australasian microtektites in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    ShyamPrasad, M.

    Thirty-three microtektites have been recovered from four different sites in the Central Indian Basin. Based on their physical properties, geographical occurrence and chemical composition, they are identified as belonging to the Australasian tektite...

  5. Factors Controlling Respiration Rates and Respired Carbon Dioxide Signatures in Riverine Ecosystems of the Amazon Basin

    Science.gov (United States)

    Ellis, E. E.; Richey, J. E.; Aufdenkampe, A. K.; Quay, P. D.; Krusche, A. V.; Alin, S. R.

    2006-12-01

    This study examined the processes controlling respiration rates observed in streams and rivers throughout the Amazon basin during the dry season by substituting spatial coverage for experimental manipulation. Throughout the Brazilian states of Amazonas and Acre, respiration rates ranged from 0.066 to 1.45 μM/hr of O2 consumed. In situ respiration was positively correlated with pH (r2=0.60), with pH values ranging from 3.95 to 8.57. Although the concentration of bulk size fractions of organic matter(dissolved organic carbon (DOC), fine particulate organic carbon, and coarse particulate organic carbon) were uncorrelated with both pH and respiration, respiration was positively correlated with the percentage of DOC that was less than 5 kDa as determined by centrifuge ultrafiltration (r2=0.52). No correlation was observed for the less than 100 kDa fraction. Further, pH was also correlated with the percentage of DOC in the <5 kDa fraction (r2=0.86), as the <5 kDa fraction increased from 34% in acidic blackwater streams to 91% in more basic whitewater rivers. These results suggest that low molecular weight organic matter (LMWOM, <5 kDa) is labile and supports higher respiration rates as compared to high molecular weight organic matter, and that pH may control the size distribution of dissolved organic matter. Further, at high pH sites with high respiration rates, net primary production ranged from 3.54 to 13.5 μM/hr of O2 produced. These rates suggest that higher pH sites are dominated by in situ production, resulting in high yields of LMWOM, which is rapidly consumed during the dry season. The 13C of respired CO2 was monitored during bottle incubations to characterize the source of organic matter being respired. Values ranged from -15.2 to -27.0‰, similar to the 13C of DIC at each site, indicating that respiration is a key process controlling the δ13C of the DIC. Furthermore, there is a positive correlation between the δ13C of respired CO2 and respiration rate (r2

  6. Potamotrygon limai, sp. nov., a new species of freshwater stingray from the upper Madeira River system, Amazon basin (Chondrichthyes: Potamotrygonidae).

    Science.gov (United States)

    Fontenelle, João Pedro; Da Silva, João Paulo C B; De Carvalho, Marcelo R

    2014-01-01

    Potamotrygon limai, sp. nov., is described from the Jamari River, upper Madeira River system (Amazon basin), state of Rondônia, Brazil. This new species differs from congeners by presenting unique polygonal or concentric patterns formed by small whitish spots better defined over the posterior disc and tail-base regions. Potamotrygon limai, sp. nov., can be further distinguished from congeners in the same basin by other characters in combination, such as two to three rows of midtail spines converging to a single irregular row at level of caudal sting origin, proportions of head, tail and disc, patterns of dermal denticles on rostral, cranial and tail regions, among other features discussed herein. Potamotrygon limai, sp. nov., is most similar to, and occurs sympatrically with, P. scobina, and is distinguished from it by lacking ocellated spots on disc, by its characteristic polygonal pattern on posterior disc, a comparatively much shorter and broader tail, greater intensity of denticles on disc, more midtail spine rows at tail-base, and other features including size at maturity and meristic characters. Potamotrygon limai, sp. nov., is also distinguished from other species of Potamotrygon occurring in the Amazon region, except P. scobina, by presenting three angular cartilages (vs. two or one). This new species was discovered during a detailed taxonomic and morphological revision of the closely related species P. scobina, and highlights the necessity for thorough and all-embracing taxonomic studies, particularly in groups with pronounced endemism and morphological variability. PMID:24870898

  7. Some Key Issues in Intercultural Bilingual Education Teacher Training Programmes--as Seen from a Teacher Training Programme in the Peruvian Amazon Basin.

    Science.gov (United States)

    Trapnell, Lucy A.

    2003-01-01

    Presents a critical reflection of the author's 14-year experience in the Teacher Training Program for Intercultural Bilingual Education in the Peruvian Amazon Basin, developed by a national Peruvian indigenous confederation and the Loreto state teacher training college. Focuses on ethical, political, and pedagogical challenges that intercultural…

  8. Molecular diagnosis of the arowanas Osteoglossum ferreirai Kanazawa, 1966 and O. bicirrhossum (Cuvier, 1829 from the Orinoco and Amazon River basins

    Directory of Open Access Journals (Sweden)

    Maria Doris Escobar L.

    2013-06-01

    Full Text Available The arowanas, fishes of Gondwanan origin, are represented in South America by the genus Osteoglossum. All species were initially reported as being exclusive to the Amazon region, with O. ferreirai restricted to the Negro River basin and O. bicirrhosum to the Amazon and Essequibo Rivers basin. Starting in the mid 1970's it was reported that O. ferreirai also occurs in the Orinoco River basin. In all regions the arowanas assumed significant socio-economic importance due to their popularity in the international ornamental fish trade, leading to over-exploitation of both species in some areas. The Orinoco populations are particularly heavily exploited, and thus conservation and management measures are needed. Both depend on the clarification of taxonomic status, and phylogenetic distinctness of the Orinoco populations. With the goal of molecularly characterizing the two species of Osteoglossum, and comparing populations of Osteoglossum from the Orinoco and Amazon basins, we characterized individuals sampled from eight localities, one in the Orinoco River basin and seven in the Amazon River basin. We sampled 39 individuals, obtaining 1004 base pairs, of which 79 were synapomorphies. Genetic distance between the two species calculated using the HKY + G model of molecular evolution was 8.94%. Intraspecific distances ranged from 0.42% in O. bicirrhosum to 0.10% in O. ferreirai. The genetic characterization confirmed the taxonomic status of O. ferreirai in the Orinoco basin, and suggested that its distribution in the Orinoco basin is unlikely to be the result of vicariance or natural dispersal, but rather an anthropic introduction.

  9. Methane emissions from floodplains in the Amazon Basin: towards a process-based model for global applications

    Directory of Open Access Journals (Sweden)

    B. Ringeval

    2013-10-01

    Full Text Available Tropical wetlands are estimated to represent about 50% of the natural wetland emissions and explain a large fraction of the observed CH4 variability on time scales ranging from glacial-interglacial cycles to the currently observed year-to-year variability. Despite their importance, however, tropical wetlands are poorly represented in global models aiming to predict global CH4 emissions. This study documents the first regional-scale, process-based model of CH4 emissions from tropical floodplains. The LPX-Bern Dynamic Global Vegetation Model (LPX hereafter was modified to represent floodplain hydrology, vegetation and associated CH4 emissions. The extent of tropical floodplains was prescribed using output from the spatially-explicit hydrology model PCR-GLOBWB. We introduced new Plant Functional Types (PFTs that explicitly represent floodplain vegetation. The PFT parameterizations were evaluated against available remote sensing datasets (GLC2000 land cover and MODIS Net Primary Productivity. Simulated CH4 flux densities were evaluated against field observations and regional flux inventories. Simulated CH4 emissions at Amazon Basin scale were compared to model simulations performed in the WETCHIMP intercomparison project. We found that LPX simulated CH4 flux densities are in reasonable agreement with observations at the field scale but with a~tendency to overestimate the flux observed at specific sites. In addition, the model did not reproduce between-site variations or between-year variations within a site. Unfortunately, site informations are too limited to attest or disprove some model features. At the Amazon Basin scale, our results underline the large uncertainty in the magnitude of wetland CH4 emissions. In particular, uncertainties in floodplain extent (i.e., difference between GLC2000 and PCR-GLOBWB output modulate the simulated emissions by a factor of about 2. Our best estimates, using PCR-GLOBWB in combination with GLC2000, lead to

  10. Optically stimulated luminescence dating of archaeological ceramics from Osvaldo and Lago Grande sites in central Amazon

    Energy Technology Data Exchange (ETDEWEB)

    Hazenfratz, Roberto; Tudela, Diego R.G.; Munita, Casimiro S., E-mail: robertohm@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Mittani, Juan C.R.; Tatumi, Sonia H. [Universidade Federal de Sao Paulo (UNIFESP), Santos, SP (Brazil)

    2013-07-01

    Thermoluminescence (TL) and optically stimulated luminescence (OSL) dating are two important techniques for dating archaeological and geological material, especially suitable for archaeological ceramics, where samples for {sup 14}C dating are not available. In this work, five pottery shards from Osvaldo and Lago Grande archaeological sites were dated by OSL. For measurements, it was used the SAR protocol. The annual dose rates were estimated by the contents of U, Th and K, determined by instrumental neutron activation analysis (INAA) of the pottery shards and clay samples near both sites. Lago Grande and Osvaldo represent a microcosm of the region, and their proximity and high density of archaeological record turn them interesting to study possible relations of cultural and/or commercial exchange. Calculations showed that the water content is an important variable that cannot be neglected in OSL dating of pottery shards from central Amazon, due to the high humidity in regional soils. The results between 867 ± 101 and 1154 ± 62 years AD agreed with the average time span for the archaeological sites occupation found in the literature. (author)

  11. Optically stimulated luminescence dating of archaeological ceramics from Osvaldo and Lago Grande sites in central Amazon

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) and optically stimulated luminescence (OSL) dating are two important techniques for dating archaeological and geological material, especially suitable for archaeological ceramics, where samples for 14C dating are not available. In this work, five pottery shards from Osvaldo and Lago Grande archaeological sites were dated by OSL. For measurements, it was used the SAR protocol. The annual dose rates were estimated by the contents of U, Th and K, determined by instrumental neutron activation analysis (INAA) of the pottery shards and clay samples near both sites. Lago Grande and Osvaldo represent a microcosm of the region, and their proximity and high density of archaeological record turn them interesting to study possible relations of cultural and/or commercial exchange. Calculations showed that the water content is an important variable that cannot be neglected in OSL dating of pottery shards from central Amazon, due to the high humidity in regional soils. The results between 867 ± 101 and 1154 ± 62 years AD agreed with the average time span for the archaeological sites occupation found in the literature. (author)

  12. Length variation of Gravity-Driven systems in the Amazon River Mouth Basin: a history of carbonate-siliciclastic sedimentation and post-rift subsidence

    Science.gov (United States)

    Cruz, Alberto; Gorini, Christian; Letouzey, Jean; Suc, Jean-Pierre; Reis, Tadeu; Silva, Cleverson; Le Bouteiller, Pauline; Granjeon, Didier; Haq, Bilal; Delprat-Jannaud, Florence

    2016-04-01

    This study address the post-rift sedimentary record of the Amazon River Mouth Basin with a focus on gravity tectonics. We investigate shale detachment layers and the timing of different gravity deformation phases. Our study was based on more than 20,000 km of 2D multi-channel seismic data, 4,453 km2 of 3D multi-channel seismic data and 40 exploratory well data. A reliable age model was constructed based on biostratigraphic data. Five industry wells on the shelf/upper slope region and seven scientific wells drilled by DSDP and ODP in the distal Ceará Rise region were used for platform and deep environments correlations. This allowed us to calibrate the seismic lines and compare the sedimentation rates in different domains of the basin (e.g. shelf, slope, deep basin). In the Basin's shelf a widespread carbonate sequence dated as Late Paleocene grew up over a Latest Albian to Early Paleocene prograding clastic sequence. From the Eocene to the Late Miocene a mixed siliciclastic-carbonate aggrading megasequence developed. The first gravitational deformation event took place during the Eocene. The proximal limit (normal faults) of this this gravity-deformation system occurs along the hinge line. The major and deeper detachment layer was identified within the previously deposed Late Cretaceous-Early Paleocene stratigraphic sequence (Cenomanian-Turonian deep shale source rock?). Further downslope, during the same period a stack of thrust sheets was created. In the central part of the Basin, a second gravitational deformation phase took place from Late Oligocene to early Late Miocene. During this period the basal detachment layer (Late Cretaceous?) was reactivated and the frontal thrust sheet created ridges and piggy-back basins. From the Late Miocene to present time, a major increase in the siliciclastic sedimentation rates was evidenced in the axis of the modern Amazon Delta. A huge aggrading-prograding mega-sequence forced the expansion of a third gravitational system

  13. Ranching in the Amazon basin - Large-scale changes observed by AVHRR

    Science.gov (United States)

    Malingreau, J. P.; Tucker, C. J.

    1990-01-01

    The contribution that AVHRR data can make to resolving the controversy about the deforestation of the Amazon region is discussed. The most significant types of information which such data can supply are pointed out. A color composite is shown and discussed, showing how it points out areas of deforestation.

  14. Chronological studies of tree-rings from the Amazon Basin using thick target PIXE and proton backscattering analysis

    International Nuclear Information System (INIS)

    A tree-core sample (Aspidosperma obscurinervium, popular name: 'pequia marfim') about 161 years old (cut in 1990), from the Ducke Reserve at the Amazon Basin, Manaus, Brazil was analyzed by PIXE (Particle Induced X-ray Emission) and proton backscattering in 136 different spots along its life. Twenty-two elements plus the density of the wood were measured (C, O, H, Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Co, Rb, W and Pb). Average C, O, and H results (49.77% ± 0.15%, 44.29% ± 0.14% and 5.95% ± 0.12%, respectively) compare well with literature values for the biomass in the Amazon region. The variability of trace elements along the tree rings showed important features that could be caused by modifications in the environment during the life of the tree. The well behaved variability of some trace elements (like K, P, Mn, Ca, etc.) seems to reflect the physiological response of the tree to external changes in the environment. The concentration of K varied from about 4 up to 2000 ppm in a given period of the life of the tree. The same period also shows important changes in the bulk composition and structure of the rings (e.g. C and density series). Multivariate statistical methods (cluster and factor analyses) were used for data interpretation, helping in the separation of periods of important transformations in the tree. The elemental time series is compared with historical records of regional development and with some global events that could possibly affect the tree. The period of maximum variation in the elemental concentrations appears to be related to the Brazilian rubber boom (1859-1912), responsible for several transformations in the Amazon region. In particular in the Manaus region, large development has occurred in the beginning of the 20th century, which are reflected in the results of this tree-core analysis

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

    NARCIS (Netherlands)

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

    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 sha

  16. 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)

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

    International Nuclear Information System (INIS)

    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)

  18. Molecular differentiation of species of the genus Zungaro (Siluriformes, Pimelodidae) from the Amazon and Paraná-Paraguay River basins in Brazil.

    Science.gov (United States)

    Boni, T A; Padial, A A; Prioli, S M A P; Lucio, L C; Maniglia, T C; Bignotto, T S; Panarari-Antunes, R S; Prioli, R A; Prioli, A J

    2011-01-01

    Fish species of the Zungaro genus (Siluriformes, Pimelodidae) are amongst the largest migratory fish in Latin America and have considerable economic importance for commercial fishing in Brazil. However, natural populations of this large catfish are experiencing a severe decline. There are significant taxonomical inconsistencies for this fish. Two geographically separated species of the fish were initially described, one endemic in the Amazon and another in the Paraná-Paraguay River basins. A taxonomic review had recently proposed that there is only one Zungaro species in Brazil, based on morphological data. We made a molecular study of Zungaro populations in an attempt to solve taxonomical inconsistencies and to analyze genetic diversity in natural populations of this genus. We analyzed two regions of the mitochondrial DNA (the control region and the ATPase 6 gene region) of individuals sampled from the Paraná-Paraguay River and Amazon River basins. Analyses based on p-distances and maximum likelihood phylogenetic models showed a genetic difference between populations corresponding to different species. Genetic differentiation between Zungaro populations was at the same level as that observed between other Siluriformes species, using the same DNA sequences. We conclude that Zungaro species of the Paraná-Paraguay River basin do not belong to the same species found in the Amazon basin. This finding has a significant implication for conservation of this fish, given that populations are disappearing at a high rate in the Paraná-Paraguay River basin, mainly due to impoundments. PMID:22095604

  19. Delimiting Evolutionarily Significant Units of the Fish, Piaractus brachypomus (Characiformes: Serrasalmidae), from the Orinoco and Amazon River Basins with Insight on Routes of Historical Connectivity.

    Science.gov (United States)

    Escobar, Maria Doris; Andrade-López, Juana; Farias, Izeni P; Hrbek, Tomas

    2015-01-01

    The freshwater fish Piaractus brachypomus is an economically important for human consumption both in commercial fisheries and aquaculture in all South American countries where it occurs. In recent years the species has decreased in abundance due to heavy fishing pressure. The species occurs in the Amazon and Orinoco basins, but lack of meristic differences between fishes from the 2 basins, and extensive migration associated with reproduction, have resulted in P. brachypomus being considered a single panmictic species. Analysis of 7 nuclear microsatellites, mitochondrial DNA sequences (D-loop and COI), and body shape variables demonstrated that each river basin is populated by a distinct evolutionarily significant unit (ESU); the 2 groups had an average COI divergence of 3.5% and differed in body depth and relative head length. Historical connection between the 2 basins most probably occurred via the Rupununi portal rather than via the Casiquiare canal. The 2 ESUs will require independent fishery management, and translocation of fisheries stocks between basins should be avoided to prevent loss of local adaptations or extinction associated with outbreeding depression. Introductions of fishes from the Orinoco basin into the Putumayo River basin, an Amazon basin drainage, and evidence of hybridization between the 2 ESUs have already been detected. PMID:26245778

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    E. Joetzjer

    2012-11-01

    Full Text Available 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.

  2. Evidence for recent hydrothermal activity in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; ShyamPrasad, M.; Gupta, S.M.; Charan, S.N.

    /89 and SS10/657 were mounted in epoxy, ground and polished to expose the internal features, and then sputter Hydrothermal activity in the Central Indian Basin 1169 8”Oo’. 16”0( Fig. 1. Physiographic features of the Central Indian Basin. FZ 1... determined with pure Ni and pyrite standards, respectively. The polished sections of the spherules were analysed on a flat surface with an accuracy of 0.1%. The ochrous sediments, due to their porous nature, gave lesser totals and hence only those totals...

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

    Directory of Open Access Journals (Sweden)

    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.

  4. A Conceptual model of Ecophysiological Function across the Amazon Basin using a Synthesis of Observed and Model Data.

    Science.gov (United States)

    Baker, I. T.; Denning, A. S.; Harper, A. B.

    2008-12-01

    Observations of the seasonal cycle of Net Ecosystem Exchange of Carbon (NEE) are variable across the Amazon Basin. NEE has been observed to be nearly uniform through the year at sites such as Cueiras Reserve in Amazonas. A pattern of efflux during the wet season and uptake during seasonal drought has been observed at multiple sites in the Tapajos River National Forest, while the opposite pattern (uptake during wet season, efflux during seasonal drought) has been observed at several sites in Mato Grosso . Using a synthesis of eddy covariance flux observations from multiple sites across vegetation and moisture gradients in the Amazon basin and a biophysical model (Simple Biosphere Model, SiB), we construct a conceptual model of the patterns of ecophysiological function that determine annual cycles and interannual variability in observed NEE across tropical Amazonia. We identify several factors that determine the behavior of Gross Primary Productivity (GPP) and respiration fluxes, while NEE is determined by their sum. We evaluate our conceptual model across a pseudo-latitudinal gradient from extremely wet (more than 2000 mm annual precipitation) in the north to drier cerrado (savanna) regions in the south. In the extremely wet regions near the equator we find little or no stress on photosynthesis and, subsequently, little or no variability in annual cycles of energy or carbon flux. In these regions NEE is determined by vegetation response to high-frequency meteorological events. As precipitation decreases, the flux seasonality increases and phase relationships between GPP and respiration determine annual NEE cycles. As GPP/respiration cycles transition from an out-of-phase relationship in wetter regions to an in-phase pattern in the cerrado, NEE changes from dry to wet season carbon uptake.

  5. Deforestation fires versus understory fires in the Amazon Basin: What can we learn from satellite-based CO measurements?

    Science.gov (United States)

    Martinez-Alonso, S.; Deeter, M. N.; Worden, H. M.; Gille, J. C.; Clerbaux, C.; George, M.

    2014-12-01

    Deforestation fires in the Amazon Basin abound during the dry season (July to October) and are mostly associated with "slash and burn" agricultural practices. Understory fires occur when fires escape from deforested areas into neighboring standing forests; they spread slowly below the canopy, affecting areas that may be comparable or even larger than clear-cut areas. The interannual variabilities of understory fires and deforestation rates appear to be uncorrelated. Areas burned in understory fires are particularly extensive during droughts. Because they progress below a canopy of living trees, understory fires and their effects are not as easily identifiable from space as deforestation fires. Here we analyze satellite remote sensing products for CO and fire to investigate differences between deforestation fires and understory fires in the Amazon Basin under varying climatic conditions. The MOPITT (Measurements Of Pollution In The Troposphere) instrument on board NASA's Terra satellite has been measuring tropospheric CO since 2000, providing the longest global CO record to date. IASI (the Infrared Atmospheric Sounding Interferometer) A and B are two instruments on board METOP-A and -B, respectively, measuring, among others, CO since 2006 and 2012. MODIS (the Moderate Resolution Imaging Spectroradiometer) instruments on board NASA's Terra and Aqua satellites provide, among other products, a daily record of fires and their effects since 2000 and 2002, respectively. The temporal extent of all these datasets allows for the detailed analysis of drought versus non-drought years. Initial results indicate that MOPITT CO emissions during the dry season peaked in 2005, 2007, and 2010. Those were draught years and coincide with peaks in area affected by understory fires.

  6. Offspring production in three freshwater crab species (Brachyura: Pseudothelphusidae from the Amazon region and Central America

    Directory of Open Access Journals (Sweden)

    Ingo S. Wehrtmann

    2010-01-01

    Full Text Available Freshwater crabs are an important component of the fauna of limnic environments, and out of the two true freshwater crab families present in the Neotropics, Pseudothelphusidae is the most diverse. Considering the lack of information regarding reproductive features of neotropical freshwater crabs, we studied, for the first time, the fecundity and the presence of juveniles carried by females of two pseudothelphusids from the Amazon region - Kingsleya latifrons (Randall, 1840 and Kingsleya ytupora Magalhães, 1986 - and one from Central America - Potamocarcinus magnus (Rathbun, 1896. The two Kingsleya species produced relatively few (56-114 and large eggs (1.9-3.7 mm, typical for species with an abbreviated or direct development. Recently produced eggs were substantially larger in K. latifrons (mean 2.83 mm when compared to those of K. ytupora (mean 1.87 mm; however, at the end of the embryogenesis, mean egg diameter was similar in both species. Therefore, it is assumed that hatchlings in both species should have a similar size. A brief description of attached juveniles of K. ytupora is provided. The number of juveniles varied between 30 (K. ytupora and 179 (P. magnus; two size groups of juveniles were found, which indicates that the offspring cling to their mother for a prolonged period of time. There was no significant loss of eggs and juveniles; it is assumed that parental care diminishes the loss of their offspring. We compiled the available information of reproductive aspects from freshwater crabs: egg diameter was in the range of 2-3 mm, independent of female size and fecundity, and reported egg number varied between 9 and 417 eggs.

  7. Variability of extreme rainfall over La Plata Basin and Amazon Basin in South America in model simulations of the 20th century and projections under global warming

    Science.gov (United States)

    Cavalcanti, I. F.

    2011-12-01

    The two largest river basins in South America are Amazon Basin (AMB) in the tropical region and La Plata Basin (LPB) in subtropical and extratropical regions. Extreme droughts have occurred during this decade in Amazonia region which have affected the transportation, fishing activities with impacts in the local population, and also affecting the forest. Droughts or floods over LPB have impacts on agriculture, hydroelectricity power and social life. Therefore, monthly wet and dry extremes in these two regions have a profound effect on the economy and society. Observed rainfall over Amazon Basin (AMB) and La Plata Basin (LPB) is analyzed in monthly timescale using the Standardized Precipitation Index (SPI), from 1979 to 1999. This period is taken to compare GPCP data with HADCM3 simulations (Hadley Centre) of the 20th century and to analyze reanalyses data which have the contribution of satellite information after 1979. HADCM3 projections using SRES A2 scenario is analyzed in two periods: 2000 to 2020 and 2079 to 2099 to study the extremes frequency in a near future and in a longer timescale. Extreme, severe and moderate cases are identified in the northern and southern sectors of LPB and in the western and eastern sectors of AMB. The main objective is to analyze changes in the frequency of cases, considering the global warming and the associated mechanisms. In the observations for the 20th century, the number of extreme rainy cases is higher than the number of dry cases in both sectors of LPB and AMB. The model simulates this variability in the two sectors of LPB and in the west sector of AMB. In the near future 2000 to 2020 the frequency of wet and dry extremes does not change much in LPB and in the western sector of AMB, but the wet cases increase in the eastern AMB. However, in the period of 2079 to 2099 the projections indicate increase of wet cases in LPB and increase of dry cases in AMB. The influence of large scale features related to Sea Surface Temperature

  8. Model for the isotopic fractionation of water in the Amazon basin

    International Nuclear Information System (INIS)

    Two models on the isotopic fractionation of water are presented. In the first model. It is assumed that the only source of water vapour for the Amazon region is the Atlantic Ocean, introduced by the predominant easterly winds. The second model contains the assumption that the forest also serves as a source of water vapour contributing an equal volume of water to the regional rains as the vapour of oceanic origin. (Author)

  9. 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

    Previous provenance studies along the Amazonas river have demonstrated that the Amazon drainage basin has been reorganized since the Late Cretaceous with the uplift of the Andes and the establishment of the transcontinental Amazon fluvial system from Late Miocene to Late Pleistocene (Hoorn et al., 1995; Potter, 1997, Wesselingh et al., 2002; Figueiredo et al. 2009, Campbell et al., 2006, Nogueira et al. 2013).There is a lack of data from Eastern and Central Amazonia and only limited core data from the Continental Platform near to current Amazonas river mouth. Central Amazonia is strategic to unveil the origin of Amazonas River because it represents the region where the connection of the Solimões and Amazonas basin can be studied through time (Nogueira et al. 2013). Also, there is a shortage of information on the old Precambrian and Paleozoic sediment sources relative to Cretaceous and Miocene siliciclastic deposits of the Solimões and Amazonas basins. We collected stratigraphic data, detrital zircon U-Pb ages and Nd and Hf isotopes from Precambrian, Paleozoic, Cretaceous and Miocene siliciclastic deposits of the Northwestern border of Amazonas Basin. They are exposed in the Presidente Figueiredo region and in the scarps of Amazon River, and occur to the east of the Purus Arch. This Northwest-Southeast trending structural feature that divides the Solimões and Amazonas basin was active at various times since the Paleozoic. Detrital zircon ages for the Neoproterozoic Prosperança Formation yielded a complex signature, with different populations of Neoproterozoic (550, 630 and 800 Ma) and Paleoproterozoic to Archean sources (1.6, 2.1 and 2.6 Ga). Also Nd and Hf isotopes show two groups of TDM model ages between 1.4 to 1.53 Ga and 2.2 and 3.1 Ga. Sediments typical of Paleozoic sedimentary rocks of the Nhamundá and Manacapuru Formations revealed NdTDM model ages of 1.7, 2.2 and 2.7 Ga, but Hf isotopes and U-Pb zircon ages are more varied. They characterize a

  10. Rivulus kirovskyi, a new killifish from the central Amazon, Brazil (Cyprinodontiformes: Rivulidae

    Directory of Open Access Journals (Sweden)

    Wilson J. E. M. Costa

    2004-03-01

    Full Text Available Rivulus kirovskyi, new species, from the central Amazon, lower rio Negro drainage, northern Brazil, is described. It is a member of an assemblage that includes R. amanapira, R. atratus, R. ornatus, R. rectocaudatus, R. romeri, R. tecminae, and R. uakti, and is diagnosed by a unique pattern of frontal squamation and a derived color pattern of the infraorbital region. Relationships of the new species with other taxa of the group are unclear at the present. It is similar to R. atratus, R. ornatus, and R. romeri in having an apomorphic reduction of anal-fin rays and by the absence of caudal spot in females, and similar to R. amanapira, R. rectocaudatus, R. romeri, R. tecminae, and R. uakti, by the absence of preopercular canal and dermosphenotic. Rivulus kirovskyi differs from all other species of the group by its unique color pattern of the caudal fin in males.Rivulus kirovskyi, espécie nova, da Amazônia central, drenagem do baixo rio Negro, é descrita. Ela é um membro de um agrupamento que inclui R. amanapira, R. atratus, R. ornatus, R. rectocaudatus, R. romeri, R. tecminae,e R. uakti,e é diagnosticado pelo padrão exclusivo de escamação frontal e um padrão de colorido derivado da região infra-orbital. Relações de parentesco da nova espécie com outros táxons do grupo não são presentemente claras. Ela é semelhante a R. atratus, R. ornatus e R. romeri por possuir uma redução apomórfica de raios da nadadeira anal e pela ausência de mancha caudal em fêmeas, e semelhante a R. amanapira, R. rectocaudatus, R. romeri, R. tecminae, e R. uakti, pela ausência de canal préopercular e de dermosfenótico. Rivulus kirovskyi difere de todas as outras espécies do grupo pelo padrão de colorido exclusivo da nadadeira caudal em machos.

  11. Linking carbon storage with functional diversity in tropical rainforest in the central Congo Basin

    Science.gov (United States)

    Verbeeck, Hans; Kearsley, Elizabeth; Bauters, Marijn; Beeckman, Hans; Huygens, Dries; Steppe, Kathy; Boeckx, Pascal

    2015-04-01

    This presentation will show an overview of results of the COBIMFO project (Congo basin integrated monitoring for forest carbon mitigation and biodiversity). In the framework of this project we have established 21 permanent 1 ha sampling plots in different forest types in the Yangambi reserve. This UNESCO Man and Biosphere reserve has an area of more than 6000 km² and is located in the heart of the Congo Basin near the Yangambi research station (DR Congo). Analysis of the inventory data of these plots revealed that carbon stocks in mature forests in this area of the Congo Basin are significantly lower (24%) than stocks recorded in the outer regions of the basin. These lower stocks are attributed to a lower maximal tree height (Kearsley et al. 2013). In addition to the carbon inventories we collected leaf and wood samples on all species within 95% basal area of each of the Yangambi plots. A total of 995 individuals were sampled, covering 123 tree species. On the samples we measured 15 traits related to leaf and wood morphology and functioning. In the presented study, relationships between the observed functional diversity and biomass are analysed. One of the remarkable results of our analysis is that species with a high functional distinctiveness have a low contribution to the basal area and the carbon stocks. In contrast, species with a high contribution to the carbon stock have a low contribution to the functional diversity. Similar patterns have been observed elsewhere (e.g. Amazon basin), but are now for the first time confirmed for central African rainforest. Finally, we also present the first results of an analysis of carbons stocks and functional diversity in tropical plantations from a unique 70-years old tree diversity experiment that was established during the colonial period at the Yangambi research station. Kearsley, E., de Haulleville, T., Hufkens, K., Kidimbu, A., Toirambe, B., Baert, G., Huygens, D., Kebede, Y., Defourny, P., Bogaert, J., Beeckman, H

  12. 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

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

    OpenAIRE

    Marcelo Rodrigues dos Anjos; Nadja Gomes Machado; Maria Eliana Peixoto da Silva; Wanderley Rodrigues Bastos; Márcio Rodrigues Miranda; Dario Pires Carvalho; Marília Higino Mussy; Igor Bruno Barbosa de Holanda; Marcelo Sacardi Biudes; João Ânderson Fulan

    2016-01-01

    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 ...

  14. Study of the anabranch dynamics for different sinuosity stages in the Upper Amazon River Basin

    Science.gov (United States)

    Frias, C. E.; Mendoza, A.; Dauer, K.; Abad, J. D.; Montoro, H.; Paredes, J.; Vizcarra, J.

    2013-12-01

    The Upper Peruvian Amazon River is characterized by a sequence of anabranching structures, which are composed by several channels behaving as non-developed and quasy-freely meandering channels. The widest channel in these anabranching structures is considered as the main channel or main anabranch while the other channels are secondary anabranches. Based on satellite imagery, it is observed that the main channels show different sinuosities along the Upper Peruvian Amazon River valley. Little is known about the effects of the planform characteristics of the main channel into the morphodynamics of the secondary anabranches. Thus, two study sites were selected to characterize anabranching structures with low and medium-high sinuosity main channels. For the low sinuosity main channel case, an area at the tri-point boundary between Colombia-Brazil and Peru was selected. For the medium-high sinuosity main channel case, an area upstream of Iquitos City (the largest city in the Peruvian Amazon Rainforest) was selected. A field campaign was carried out on 2010 and 2011 for the medium-high and low sinuosity stages respectively. On this field campaign velocity measurement, bathymetry and water surface elevations were obtained. With the field data it was possible to develop and validate a two dimensional shallow water numerical model to study the hydrodynamics on both sites. This allows us to discuss the effects of the current planform configuration of the anabranching structures into the short-term behavior of individual channels. In past studies, temporal analysis of the Amazon River planform have been carried out using satellite imagery with special focus into the floodplain, main channel, number of islands and valley slope. However, the dynamics in these anabranching structures containing multiple channels have not been studied in detailed. The metrics obtained for this study were sinuosity, channel width and annual migration rates. It was confirmed that in a medium to high

  15. Screening for antimicrobial activity among bacteria isolated from the Amazon Basin Atividade antimicrobiana entre bactérias isoladas da Bacia Amazônica

    OpenAIRE

    Motta, Amanda S.; Florencia Cladera-Olivera; Adriano Brandelli

    2004-01-01

    Bacteria producing antimicrobial activity were identified among 86 isolates from aquatic environments of Brazilian Amazon Basin. Antimicrobial activity against at least one indicator strain was detected for 59 isolates (68.6%). Inhibitory activity was mostly against Gram-positive bacteria, such as Listeria monocytogenes and Bacillus cereus. The antimicrobial substances produced by 19 strains that showed higher inhibitory activity were partially characterized. These antimicrobial substances sh...

  16. The optical properties of river and floodplain waters in the Amazon River Basin : implications for satellite-based measurements of suspended particulate matter

    OpenAIRE

    Martinez, Jean-Michel; Espinoza-Villar, R.; Armijos, E.; Moreira, L.S.

    2015-01-01

    Satellite images can now be used to assess river sediment discharge, and systematic studies over rivers and lakes are required to support such applications and document the variability of inland water optical properties at the watershed scale. The optical properties of the Amazon Basin waters were analyzed from in situ measurements of the remote sensing reflectance (R-rs) at 279 stations and downwelling diffuse attenuation coefficients (K-d) at 133 stations. Measurements of the apparent optic...

  17. Clinical aspects of envenomation caused by Tityus obscurus (Gervais, 1843) in two distinct regions of Pará state, Brazilian Amazon basin: a prospective case series

    OpenAIRE

    Pardal, Pedro PO; Ishikawa, Edna AY; Vieira, José LF; Coelho, Johne S; Dórea, Regina CC; Abati, Paulo AM; Quiroga, Mariana MM; Chalkidis, Hipócrates M.

    2014-01-01

    Background Scorpion envenomations are a major public health problem in Brazil, whose most dangerous cases are attributable to the genus Tityus. This study was designed to compare the clinical and demographic features of envenomations by Tityus obscurus in two areas of the state of Pará located in the Amazon basin. Were compared demographic findings, local and systemic signs and symptoms of human envenomations caused by T. obscurus that occurred in western and eastern areas of the state. Resul...

  18. Reducing forest emissions in the Amazon Basin: A review of drivers of land-use change and how payments for environmental services (PES) schemes can affect them

    OpenAIRE

    S. Wertz-Kanounnikoff; M. Kongphan-Apirak; Wunder, Sven

    2008-01-01

    Land-use change and deforestation in Latin America generally, and in the Amazon Basin specifically, are driven primarily by economic profitability (agricultural expansion and logging) and governance weaknesses (notably, lenient law enforcement), and only to a much lesser extent by deterministic poverty cycles. Nevertheless, poor forest dwellers (indigenous communities, smallholders, rubber tappers) have the potential to be important stakeholders in stabilising Amazonian land use. Changing inc...

  19. Recent history of the agriculture of the Brazilian Amazon Basin : prospects for sustainable development and a first look at the biogeochemical consequences of pasture reformation

    OpenAIRE

    Cerri, C. C.,; Melillo, J M; Feigl, B. J.,; Piccolo, M.C.; Neill, C.; Steuder, P.A.; Carvalho, M. da C.S.; Godinho, V.P.; Cerri, C. E. P.,; Bernoux, Martial

    2005-01-01

    Land-use change for human settlement and agricultural purposes, especially pasture establishment, has caused major impacts on the Amazon Basin's environment. Development of strategies for reformation and restoration of already degraded pastures constitutes the main goal of the authors' research work. For some of this work, a homogeneous area of land in terms of soil characteristics was selected at Nova Vida ranch in Rondônia state to conduct a multidisciplinary experiment, w...

  20. Total basin discharge for the Amazon and Mississippi River basins from GRACE and a land-atmosphere water balance

    OpenAIRE

    Syed, T. H; J. S. Famiglietti; Chen, J; Rodell, M.; S. I. Seneviratne; Viterbo, P; C. R. Wilson

    2005-01-01

    Freshwater discharge along continental margins is a key Earth system variable that is not well monitored globally. Here we propose a method for estimating monthly river basin outflows based on the use of new GRACE satellite estimates of terrestrial water storage changes in a coupled land-atmosphere water balance. Using GRACE land water storage changes (which include changes in groundwater storage) in the water balance method results in more holistic estimates of basin discharge, which we call...

  1. Tracking water level changes of the Amazon Basin with space-borne remote sensing and integration with large scale hydrodynamic modelling: A review

    Science.gov (United States)

    Hall, Amanda C.; Schumann, Guy J.-P.; Bamber, Jonathan L.; Bates, Paul D.

    2011-01-01

    With the improvement of remote sensing systems, in particular active sensors, our ability to make regular observations of the Amazon Basin has greatly increased. Water levels and other related features such as discharge, floodplain-river connectivity, and flood extent are now being monitored using space-borne sensors, thereby complimenting in situ gauging networks. This review concludes that the main advances remote sensing has had on our knowledge of hydrology includes the ability observe the seasonal cycles of the Amazon River across the entire basin, including the movement of the flood wave downstream. Flood extent can now be mapped, including the direction of floodplain flow, thanks to the extensive coverage provided by various active remote sensing systems. Our knowledge of the relationship between water levels in the main channel and the floodplain has been reassessed. It is now known that floodplain levels are related to the distance of the location from the main channel. The addition of new and future satellites, such as ICESat-1 and -2, GRACE and SWOT, will guarantee the continuation of research in this field and the continued advancement of knowledge and understanding of the Amazon Basin.

  2. Evolutionary model of the oblique rift basins- Central African Rifts

    Science.gov (United States)

    Yang, Kenn-Ming; Cheng, I.-Wen; Wu, Jong-Chang

    2016-04-01

    The geometry of oblique-rifting basin is strongly related with the angle (α) between the trend of rift and that of regional major extensional stress. The main purpose of this study is to investigate characteristics of geometry and kinematics of structure and tectono-stratigraphy during basin evolution of Central African Rifts (CAS). In this study, we simulated the formation of oblique-rifting basin with Particle Flow Code 3-Dimensions-(PFC 3D) and compared the simulation results with the tectonic settings of a series of basin in CAS. CAS started to develop in Early Cretaceous (130Ma) and lasted until the Late Cretaceous (85Ma-80Ma). The following collision between the African and Eurasian plates imposed compressional stress on CAS and folded the strata in the rift basins. Although the characteristics of rift basin formation remain controversial, palinspastic sections constructed in this study show that, in the Early Cretaceous, the rift basins are mainly characterized by normal faults and half-grabens. In the Late Cretaceous, the morphology of the rift basins was altered by large-scaled tectonic compression with the active Borogop Fault of regional scale. Also, en echelon trend of normal faults in the basins were measured and the angles between the trend with that of the rift axes of each basin were demonstrated, indicating that the development of CAS was affected by the regional extensional stress with a dextral component during the rifting process and, therefore, the rift basins were formed by oblique-rifting. In this study, we simulated the oblique-rifting basin model of various α with Particle Flow Code 3-Dimensions-(PFC 3D). The main theory of PFC 3D is based on the Discrete Element Method (DEM), in which parameters are applied to every particle in the models. We applied forces acting on both sides of rift axis, which α are 45°, 60°, 75° and 90° respectively, to simulate basin formation under oblique-rifting process. The study results of simulation

  3. Assessment of climate change impacts on the hydrology of the Peruvian Amazon-Andes basin

    OpenAIRE

    Casimiro, W. S. L.; Labat, D.; Guyot, Jean-Loup; Ardoin Bardin, Sandra

    2011-01-01

    In this article, we propose an investigation of the modifications of the hydrological response of two Peruvian AmazonasAndes basins in relationship with the modifications of the precipitation and evapotranspiration rates inferred by the IPCC. These two basins integrate around 10% of the total area of the Amazonian basin. These estimations are based on the application of two monthly hydrological models, GR2M and MWB3, and the climatic projections come from BCM2, CSMK3 and MIHR models for A1B a...

  4. Characteristics and Diurnal Cycle of GPM Rainfall Estimates over the Central Amazon Region

    Directory of Open Access Journals (Sweden)

    Rômulo Oliveira

    2016-06-01

    Full Text Available Studies that investigate and evaluate the quality, limitations and uncertainties of satellite rainfall estimates are fundamental to assure the correct and successful use of these products in applications, such as climate studies, hydrological modeling and natural hazard monitoring. Over regions of the globe that lack in situ observations, such studies are only possible through intensive field measurement campaigns, which provide a range of high quality ground measurements, e.g., CHUVA (Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GlobAl Precipitation Measurement and GoAmazon (Observations and Modeling of the Green Ocean Amazon over the Brazilian Amazon during 2014/2015. This study aims to assess the characteristics of Global Precipitation Measurement (GPM satellite-based precipitation estimates in representing the diurnal cycle over the Brazilian Amazon. The Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG and the Goddard Profiling Algorithm—Version 2014 (GPROF2014 algorithms are evaluated against ground-based radar observations. Specifically, the S-band weather radar from the Amazon Protection National System (SIPAM, is first validated against the X-band CHUVA radar and then used as a reference to evaluate GPM precipitation. Results showed satisfactory agreement between S-band SIPAM radar and both IMERG and GPROF2014 algorithms. However, during the wet season, IMERG, which uses the GPROF2014 rainfall retrieval from the GPM Microwave Imager (GMI sensor, significantly overestimates the frequency of heavy rainfall volumes around 00:00–04:00 UTC and 15:00–18:00 UTC. This overestimation is particularly evident over the Negro, Solimões and Amazon rivers due to the poorly-calibrated algorithm over water surfaces. On the other hand, during the dry season, the IMERG product underestimates mean precipitation in comparison to the S-band SIPAM

  5. Salt movements within the Central European basin system

    Energy Technology Data Exchange (ETDEWEB)

    Maystrenko, Yuriy; Bayer, Ulf; Scheck-Wenderoth [GeoForschungsZentrum (GFZ), Potsdam (Germany); Littke, Ralf [RWTH Aachen (Germany). Lehrstuhl fuer Geologie, Geochemie und Lagerstaetten des Erdoels und der Kohle

    2010-04-15

    Evolution of salt structures in relation to tectonic events within central part of the Central European Basin System is described by summarizing results which have been obtained and published in frame of the research project DFG-SPP 1135. These results illustrate main phases of salt tectonics within the basin system from the Triassic to present day. During the Buntsandstein and Muschelkalk, extension triggered raft tectonics and salt movements within the Ems Trough, the Glueckstadt and the Horn Grabens. The next phase of salt movements occurred in response to a Middle-Late Keuper regional extensional event which was strongest within the Triassic depocenters of the Central European Basin System, such as the Horn Graben, the Glueckstadt Graben, the Ems and the Rheinsberg Troughs. Regional erosion truncated the study area during the Late Jurassic-Early Cretaceous time. The magnitude of Late Jurassic-Early Cretaceous erosion is declining towards southern margin of the basin system where a dextral transtensional regime was established in the Lower Saxony Basin and neighboring areas during the Late Jurassic-Early Cretaceous. The late Early Cretaceous-early Late Cretaceous is characterized by a relative tectonic quiescence without strong salt movements. The Late Cretaceous-Early Cenozoic inversion provocated renewed salt movements, causing the thick-skinned salt tectonics along the Elbe Fault System and the thin-skinned character of salt movements towards the north from the area of strain localisation. Post-inversion Cenozoic subsidence was accompanied by salt movements, related either to diapiric rise due to regional shortening and/or to local almost E-W directed extension. (orig.)

  6. Towards SWOT data assimilation for hydrology : automatic calibration of global flow routing model parameters in the Amazon basin

    Science.gov (United States)

    Mouffe, M.; Getirana, A.; Ricci, S. M.; Lion, C.; Biancamaria, S.; Boone, A.; Mognard, N. M.; Rogel, P.

    2011-12-01

    The Surface Water and Ocean Topography (SWOT) mission is a swath mapping radar interferometer that will provide global measurements of water surface elevation (WSE). The revisit time depends upon latitude and varies from two (low latitudes) to ten (high latitudes) per 22-day orbit repeat period. The high resolution and the global coverage of the SWOT data open the way for new hydrology studies. Here, the aim is to investigate the use of virtually generated SWOT data to improve discharge simulation using data assimilation techniques. In the framework of the SWOT virtual mission (VM), this study presents the first results of the automatic calibration of a global flow routing (GFR) scheme using SWOT VM measurements for the Amazon basin. The Hydrological Modeling and Analysis Platform (HyMAP) is used along with the MOCOM-UA multi-criteria global optimization algorithm. HyMAP has a 0.25-degree spatial resolution and runs at the daily time step to simulate discharge, water levels and floodplains. The surface runoff and baseflow drainage derived from the Interactions Sol-Biosphère-Atmosphère (ISBA) model are used as inputs for HyMAP. Previous works showed that the use of ENVISAT data enables the reduction of the uncertainty on some of the hydrological model parameters, such as river width and depth, Manning roughness coefficient and groundwater time delay. In the framework of the SWOT preparation work, the automatic calibration procedure was applied using SWOT VM measurements. For this Observing System Experiment (OSE), the synthetical data were obtained applying an instrument simulator (representing realistic SWOT errors) for one hydrological year to HYMAP simulated WSE using a "true" set of parameters. Only pixels representing rivers larger than 100 meters within the Amazon basin are considered to produce SWOT VM measurements. The automatic calibration procedure leads to the estimation of optimal parametersminimizing objective functions that formulate the difference

  7. 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.

  8. Combination of Radar Altimeter and In-Situ Measurements to deduce Rating-Curves at Some Virtual Stations in the Ungauged Amazon and Orinoco Basins

    Science.gov (United States)

    Leon, J.; Seyler, F.; Calmant, S.; Bonnet, M.

    2008-12-01

    In the last two years, virtual gauged stations have been proposed to increase the density of hydrological network in ungauged or very poorly monitored basins (Leon, 2006). In spatial hydrology a virtual station is considered as any crossing of water body surface (i.e., large rivers) by radar altimeter satellite tracks. The main objective of this study is to review the usefulness of altimetric data presenting rating curves obtained for some virtual stations at the poorly gauged basins of Caqueta (Colombian Amazon basin), Uaupes and Upper Negro (Brazilian Amazon basin) and Upper Orinoco. Rating curve parameters at virtual stations are estimated by fitting with a power law distribution the temporal series of water surface altitude derived from ENVISAT satellite measurements and modeled discharges. The applied methodology (Leon et al. 2006a) allows the ellipsoidal height of effective zero flow to be estimated. This parameter is a good proxy of the mean water depth from which the river bed slope can be computed. These quantities combined with rating-curve parameters are highly valuable for understanding hydrological behaviour, especially at ungauged basins where hydrodynamical studies had always been prevented by the lack of in-situ data. The results obtained allow to propose a new insight into the hydrological behaviour of the region shared by Colombia, Brazil and Venezuela, which is very difficult to access, and then very poorly known.

  9. Carbon and metal concentrations, size distributions and fluxes in major rivers of the Amazon basin

    Science.gov (United States)

    Benedetti, Marc F.; Mounier, Stephane; Filizola, Naziano; Benaim, Jean; Seyler, Patrick

    2003-05-01

    The chemical composition of the Amazon River results from the mixing of two water types: black water and white water. On-site fractionation by sequential tangential ultrafiltration (STUF) was used to differentiate transported organic carbon and to determine the distribution and association of major and trace elements with different size fraction of the organic carbon (OC). Several sampling campaigns (1994-1996) allow a monthly quantification of particulate (OCP, MeP), colloidal (OCC, MeC) and dissolved (OCD, MeD) organic carbon and metal ions inputs. In white rivers the OC is mainly concentrated in the low molecular weight fraction (OCD 5 kDa). For Mg, Ca and K, 50% of the total amount of each element is found in fraction MeD while 15% and 35% are found in fractions MeC and MeP, respectively. Al and Fe are in the particulate fraction at 99% of the total metal concentration for all river samples. This work emphasizes the coagulation processes and the sink for elements in the mixing zone. These physicochemical transformations of the organic matter vary seasonally. The changes happen during the transition periods: before high-level waters and before low-level waters. By way of flux measurement, a seasonal carbon loss was observed. The estimated annual organic carbon flux of the Amazon at Òbidos is 28 × 106 t. At the same time, an average of 9 × 106 t of organic carbon per year is retained in the reach between Manaus and Òbidos, probably via coagulation processes.

  10. Seismic stratigraphic framework of deep central Gulf of Mexico basin

    Energy Technology Data Exchange (ETDEWEB)

    Shaub, F.J.; Buffler, R.T.; Parsons, J.G.

    1984-11-01

    The deep Gulf of Mexico basin is underlain by up to 10 km (33,000 ft) of Jurassic(.) to Holocene layered sedimentary rocks. The multichannel reflection seismic record from the deep Gulf of Mexico was divided into six seismic stratigraphic units for study of the geologic history of this accumulation. The basal Challenger unit (Jurassic (.) to middle Cretaceous) is considered coeval with early basin formation. We interpret it as a deep marine sequence overlying oceanic crust in the central basin and as continental and shallow through deep marine rocks, including thick evaporites, over adjacent transitional crust. The next three units, Campeche, Lower Mexican Ridges and Upper Mexican Ridges, indicate that from the Late Cretaceous through middle Miocene the basin filled progressively from the west and north, most probably with siliceous turbidites interlayered with pelagic deposits. By the late Tertiary, however, salt and shale deformation within thick sedimentary sections along the western and northern margins trapped much of the incoming sediment supply on the shelves and upper slopes. The late Miocene to Pliocene Cinco de Mayo unit, therefore, represents a relatively starved interval. In contrast, the uppermost, or Sigsbee unit, includes the Mississippi Fan, an accumulation up to 3 km (10,000 ft) thick of mainly mass-transported deposits that bypassed the shelf and slope and were deposited directly onto the abyssal plain. In the western and southwestern portions of the deep basin, beyond the fan pinchout, the Pleistocene section is largely a continuation of the Pliocene suspension deposits.

  11. Central Coast Region South District Basin Planning & Habitat Mapping Project

    OpenAIRE

    Watson, Jessica; Casagrande, Julie; Watson, Fred

    2008-01-01

    This is a report to the California Department of Fish and Game. Between 2003 and 2008, the Foundation of CSUMB produced fish habitat maps and GIS layers for CDFG based on CDFG field data. This report describes the data entry, mapping, and website construction procedures associated with the project. Included are the maps that have been constructed. This report marks the completion of the Central Coast region South District Basin Planning and Habitat Mapping Project. (Document contains 40 pages)

  12. Geochemistry of polymetallic nodules from the Central Indian Ocean basin

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.; Khadge, N.H.; Desa, J.A.E.

    ; \\[\\] > l0 cm. Pacific Ocean; A nodules; x sediments. Average shale values from Piper (1974). POLYMETALLIC NODULES FROM THE CENTRAL INDIAN OCEAN BASIN TABLE 3A Inter-element relationship in the CIOB nodules Moisture Mn Fe Cu Ni Co Cu + Ni + Co Moisture...-242. Lyle, M., 1982. Estimating growth rates of ferromanganese nodules from chemical composition: implications for nodule formation processes. Geochim. Cosmochem. Acta., 46: 2301- 2306. Piper, D.Z., 1974. Rare earth elements and the sedimentary cycle: A...

  13. Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest

    OpenAIRE

    Jardine, Kolby J.; Chambers, Jeffrey Q.; Jennifer Holm; Jardine, Angela B.; Clarissa G. Fontes; Zorzanelli, Raquel F.; Meyers, Kimberly T.; Vinicius Fernadez de Souza; Sabrina Garcia; Bruno O. Gimenez; Luani R. de O. Piva; Niro Higuchi; Paulo Artaxo; Scot Martin; Manzi, Antônio O.

    2015-01-01

    Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV) emissions during membrane peroxid...

  14. Are rapids a barrier for floodplain fishes of the Amazon basin? A demographic study of the keystone floodplain species Colossomamacropomum (Teleostei: Characiformes).

    Science.gov (United States)

    Farias, Izeni Pires; Torrico, Juan Pablo; García-Dávila, Carmen; Santos, Maria da Conceição Freitas; Hrbek, Tomas; Renno, Jean-François

    2010-09-01

    We investigated demographic history and population structuring of Colossoma macropomum sampled from 14 localities in the Amazon basin and the Bolivian sub-basin; the two basins are separated by a series of 16 rapids. Although genetically differentiated, IMa analyses suggest non-zero bi-directional migration rates, and inter-basin divergence of approximately 17 thousand years ago. Analyses in BEAST indicated that Bolivian C. macropomum has been demographically stable except for a moderate population increase in the last 12 thousand years, while Amazonian C. macropomum has been experiencing demographic growth over the last 350 thousand years, resulting in approximately one order of magnitude increase in coalescent N(e). PMID:20362063

  15. XX/XO, a rare sex chromosome system in Potamotrygon freshwater stingray from the Amazon Basin, Brazil.

    Science.gov (United States)

    de Souza Valentim, Francisco Carlos; Porto, Jorge Ivan Rebelo; Bertollo, Luiz Antonio Carlos; Gross, Maria Claudia; Feldberg, Eliana

    2013-09-01

    Potamotrygonidae is a representative family of South American freshwater elasmobranchs. Cytogenetic studies were performed in a Potamotrygon species from the middle Negro River, Amazonas, Brazil, here named as Potamotrygon sp. C. Mitotic and meiotic chromosomes were analyzed using conventional staining techniques, C-banding, and detection of the nucleolus organizing regions (NOR) with Silver nitrate (Ag-NOR). The diploid number was distinct between sexes, with males having 2n = 67 chromosomes, karyotype formula 19m + 8sm + 10st + 30a, and fundamental number (FN) = 104, and females having 2n = 68 chromosomes, karyotype formula 20m + 8sm + 10st + 30a, and FN = 106. A large chromosome, corresponding to pair number two in the female karyotype, was missing in the male complement. Male meiotic cells had 33 bivalents plus a large univalent chromosome in metaphase I, and n = 33 and n = 34 chromosomes in metaphase II. These characteristics are consistent with a sex chromosome system of the XX/XO type. Several Ag-NOR sites were identified in both male and female karyotypes. Positive C-banding was located only in the centromeric regions of the chromosomes. This sex chromosome system, which rarely occurs in fish, is now being described for the first time among the freshwater rays of the Amazon basin. PMID:24068425

  16. Effect of artesunate-mefloquine fixed-dose combination in malaria transmission in amazon basin communities

    Directory of Open Access Journals (Sweden)

    Santelli Ana C

    2012-08-01

    Full Text Available Abstract Background Studies in South-East Asia have suggested that early diagnosis and treatment with artesunate (AS and mefloquine (MQ combination therapy may reduce the transmission of Plasmodium falciparum malaria and the progression of MQ resistance. Methods The effectiveness of a fixed-dose combination of AS and MQ (ASMQ in reducing malaria transmission was tested in isolated communities of the Juruá valley in the Amazon region. Priority municipalities within the Brazilian Legal Amazon area were selected according to pre-specified criteria. Routine national malaria control programmatic procedures were followed. Existing health structures were reinforced and health care workers were trained to treat with ASMQ all confirmed falciparum malaria cases that match inclusion criteria. A local pharmacovigilance structure was implemented. Incidence of malaria and hospitalizations were recorded two years before, during, and after the fixed-dose ASMQ intervention. In total, between July 2006 and December 2008, 23,845 patients received ASMQ. Two statistical modelling approaches were applied to monthly time series of P. falciparum malaria incidence rates, P. falciparum/Plasmodium vivax infection ratio, and malaria hospital admissions rates. All the time series ranged from January 2004 to December 2008, whilst the intervention period span from July 2006 to December 2008. Results The ASMQ intervention had a highly significant impact on the mean level of each time series, adjusted for trend and season, of 0.34 (95%CI 0.20 – 0.58 for the P. falciparum malaria incidence rates, 0.67 (95%CI 0.50 – 0.89 for the P. falciparum/P. vivax infection ratio, and 0.53 (95%CI 0.41 – 0.69 for the hospital admission rates. There was also a significant change in the seasonal (or monthly pattern of the time series before and after intervention, with the elimination of the malaria seasonal peak in the rainy months of the years following the introduction of ASMQ. No

  17. 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. PMID:19215149

  18. 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

  19. Influence of environmental variables on the density of shrub and tree seedlings in an Upland Forest in the Central Amazon

    Directory of Open Access Journals (Sweden)

    Randolpho Gonçalves Dias Terceiro

    2014-09-01

    Full Text Available This research aimed to evaluate the influence of luminosity and distance from an igarapé on seedling density in an upland forest in the Central Amazon. Twenty plots were installed, where we measured the percentage of canopy openness, and the distance from an igarapé, and we also counted the number of seedlings. We obtained a linear regression of canopy openness with the seedling density and an ANOVA of seedling density according to the distance from an igarapé. We registered a total of 229 seedling individuals (seedling density = 11 plants/m2. Among the environmental variables measured, only canopy openness has positively influenced on seedling density. Small amplitude in the increase in luminosity can cause an increased seedling density. Seedling density did not differ with regard to the distance from an igarapé, due to low competitiveness and adaptations by species occurring in the wetlands.

  20. Hydrochemistry of the Parauari-Maues Acu river basin (Amazon region, Brazil)

    International Nuclear Information System (INIS)

    The chemical composition of the Parauari-Maues Acu basin is studied through the determination of pH, calcium, magnesium, iron, chloride, sodium, potassium, zinc, copper and manganese. Four expeditions were made and samples were collected in 16 different points of the main course. Chemical analysis of the rivers waters shows seasonal flutuations of the concentrations of the elements in the main river as well as in the main afluents like Nambi river, Amana river and Urupadi river. (Author)

  1. Neutrons, radiation and archaeology: a multi analytical case study of incised rim tradition ceramics in Central Amazon

    International Nuclear Information System (INIS)

    This thesis is an interdisciplinary archaeometric study involving archaeological ceramic material from two large archaeological sites in Central Amazon, namely Lago Grande and Osvaldo, on the confluence region of Negro and Solimoes rivers. It was tested a hypothesis about the existence of an exchange network between the former inhabitants of those sites, focusing on material and/or technological exchange. That hypothesis has implications for archaeological theories of human occupation of the pre-colonial Central Amazon, which try to relativise the role of ecological difficulties of the tropical forest as a limiting factor for the emergence of social complexity in the region. The physical-chemical characterization of potsherds and clay samples near the sites was carried out by: instrumental neutron activation analysis (INAA) to determine the elemental chemical composition; electron paramagnetic resonance (EPR) to determine the firing temperature; X-ray diffraction (XRD) to determine the mineralogical composition; and dating by optically stimulated luminescence (OSL). Previous studies showed that Osvaldo and Lago Grande were occupied by people which produced pottery classified in the Manacapuru and Paredao phases, subclasses of the Incised Rim Tradition, around the 5-10th and 7-12th centuries BC, respectively. INAA results were analyzed by multivariate statistical methods, whereby two chemical groups of pottery were defined for each archaeological site. Significant variation in firing temperatures and mineralogical composition were not identified for such groups. By integration of the results with archaeological data, the superposition between pairs of chemical groups was interpreted as a correlate of an ancient exchange network, although it was not possible to define if it existed exclusively between Lago Grande and Osvaldo. On the contrary, it was suggested that Lago Grande participated in a more extensive exchange network by comparison of two chemical groups

  2. 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

  3. A test of the cosmogenic 10Be(meteoric)/9Be proxy for simultaneously determining basin-wide erosion rates, denudation rates, and the degree of weathering in the Amazon basin

    Science.gov (United States)

    Wittmann, H.; Blanckenburg, F.; Dannhaus, N.; Bouchez, J.; Gaillardet, J.; Guyot, J. L.; Maurice, L.; Roig, H.; Filizola, N.; Christl, M.

    2015-12-01

    We present an extensive investigation of a new erosion and weathering proxy derived from the 10Be(meteoric)/9Be(stable) ratio in the Amazon River basin. This new proxy combines a radioactive atmospheric flux tracer, meteoric cosmogenic 10Be, with 9Be, a trace metal released by weathering. Results show that meteoric 10Be concentrations ([10Be]) and 10Be/9Be ratios increase by >30% from the Andes to the lowlands. We can calculate floodplain transfer times of 2-30 kyr from this increase. Intriguingly however, the riverine exported flux of meteoric 10Be shows a deficit with respect to the atmospheric depositional 10Be flux. Most likely, the actual area from which the 10Be flux is being delivered into the mainstream is smaller than the basin-wide one. Despite this imbalance, denudation rates calculated from 10Be/9Be ratios from bed load, suspended sediment, and water samples from Amazon Rivers agree within a factor of 2 with published in situ 10Be denudation rates. Erosion rates calculated from meteoric [10Be], measured from depth-integrated suspended sediment samples, agree with denudation rates, suggesting that grain size-induced variations in [10Be] are minimized when using such sampling material instead of bed load. In addition, the agreement between erosion and denudation rates implies minor chemical weathering intensity in most Amazon tributaries. Indeed, the Be-specific weathering intensity, calculated from mobilized 9Be comprising reactive and dissolved fractions that are released during weathering, is constant at approximately 40% of the total denudation from the Andes across the lowlands to the Amazon mouth. Therefore, weathering in the Amazon floodplain is not detected.

  4. Atmosphere-biosphere exchange of CO2 and O3 in the Central Amazon Forest

    Science.gov (United States)

    Fan, Song-Miao; Wofsy, Steven C.; Bakwin, Peter S.; Jacob, Daniel J.; Fitzjarrald, David R.

    1990-01-01

    An eddy correlation measurement of O3 deposition and CO2 exchange at a level 10 m above the canopy of the Amazon forest, conducted as part of the NASA/INPE ABLE2b mission during the wet season of 1987, is presented. It was found that the ecosystem exchange of CO2 undergoes a well-defined diurnal variation driven by the input of solar radiation. A curvilinear relationship was found between solar irradiance and uptake of CO2, with net CO2 uptake at a given solar irradiance equal to rates observed over forests in other climate zones. The carbon balance of the system appeared sensitive to cloud cover on the time scale of the experiment, suggesting that global carbon storage might be affected by changes in insolation associated with tropical climate fluctuations. The forest was found to be an efficient sink for O3 during the day, and evidence indicates that the Amazon forests could be a significant sink for global ozone during the nine-month wet period and that deforestation could dramatically alter O3 budgets.

  5. Influence of biomass aerosol on precipitation over the Central Amazon: an observational study

    Science.gov (United States)

    Gonçalves, W. A.; Machado, L. A. T.; Kirstetter, P.-E.

    2015-06-01

    Understanding the influence of biomass burning aerosol on clouds and precipitation in the Amazon is key to reducing uncertainties in simulations of climate change scenarios with regard to deforestation fires. Here, we associate rainfall characteristics obtained from an S-band radar in the Amazon with in situ measurements of biomass burning aerosol for the entire year of 2009. The most important results were obtained during the dry season (July-December). The results indicate that the influence of aerosol on precipitating systems is modulated by the atmospheric degree of instability. For less unstable atmospheres, the higher the aerosol concentration is, the lower the precipitation is over the region. In contrast, for more unstable cases, higher concentrations of black carbon are associated with greater precipitation, increased ice content, and larger rain cells; this finding suggests an association with long-lived systems. The results presented are statistically significant. However, due to limitations imposed by the available data set, important features, such as the contribution of each mechanism to the rainfall suppression, need further investigation. Regional climate model simulations with aircraft and radar measurements would help clarify these questions.

  6. Highways and outposts: economic development and health threats in the central Brazilian Amazon region

    Directory of Open Access Journals (Sweden)

    Damacena Giseli N

    2010-06-01

    Full Text Available Abstract Background Economic development is often evoked as a driving force that has the capacity to improve the social and health conditions of remote areas. However, development projects produce uneven impacts on local communities, according to their different positions within society. This study examines the spatial distribution of three major health threats in the Brazilian Amazon region that may undergo changes through highway construction. Homicide mortality, AIDS incidence and malaria prevalence rates were calculated for 70 municipalities located within the areas of influence of the Cuiabá-Santarém highway (BR-163, i.e. in the western part of the state of Pará state and the northern part of Mato Grosso. Results The municipalities were characterized using social and economic indicators such as gross domestic product (GDP, urban and indigenous populations, and recent migration. The municipalities' connections to the region's main transportation routes (BR-163 and Trans-Amazonian highways, along with the Amazon and Tapajós rivers were identified by tagging the municipalities that have boundaries crossing these routes, using GIS overlay operations. Multiple regression was used to identify the major driving forces and constraints relating to the distribution of health threats. The main explanatory variables for higher malaria prevalence were: proximity to the Trans-Amazonian highway, high proportion of indigenous population and low proportion of migrants. High homicide rates were associated with high proportions of migrants, while connection to the Amazon River played a protective role. AIDS incidence was higher in municipalities with recent increases in GDP and high proportions of urban population. Conclusions Highways induce social and environmental changes and play different roles in spreading and maintaining diseases and health threats. The most remote areas are still protected against violence but are vulnerable to malaria. Rapid

  7. Cosmogenic Nuclide Budgeting of Floodplain Sediment Transfer and Examples from the Amazon Basin

    OpenAIRE

    H. Wittmann; F. von Blanckenburg; P. Kubik

    2009-01-01

    Cosmogenic nuclides measured in river sediment can be used to provide basin-wide, spatially-averaged denudation rates over time scales meaningful to rock weathering and erosion itself, thus bridging the gap between long-term denudation rates from thermo-chronology and lake fills and short-term river loads [1-4]. In this study, we assess the effects of sediment deposition and storage on this method, because cosmogenic nuclides may be prone to additional irradiation or decay during long-term st...

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

    OpenAIRE

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

    2014-01-01

    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, phen...

  9. Automatic calibration of a global flow routing model in the Amazon basin using virtual SWOT data

    Science.gov (United States)

    Rogel, P. Y.; Mouffe, M.; Getirana, A.; Ricci, S. M.; Lion, C.; Mognard, N. M.; Biancamaria, S.; Boone, A.

    2012-12-01

    The Surface Water and Ocean Topography (SWOT) wide swath altimetry mission will provide a global coverage of surface water elevation, which will be used to help correct water height and discharge prediction from hydrological models. Here, the aim is to investigate the use of virtually generated SWOT data to improve water height and discharge simulation using calibration of model parameters (like river width, river depth and roughness coefficient). In this work, we use the HyMAP model to estimate water height and discharge on the Amazon catchment area. Before reaching the river network, surface and subsurface runoff are delayed by a set of linear and independent reservoirs. The flow routing is performed by the kinematic wave equation.. Since the SWOT mission has not yet been launched, virtual SWOT data are generated with a set of true parameters for HyMAP as well as measurement errors from a SWOT data simulator (i.e. a twin experiment approach is implemented). These virtual observations are used to calibrate key parameters of HyMAP through the minimization of a cost function defining the difference between the simulated and observed water heights over a one-year simulation period. The automatic calibration procedure is achieved using the MOCOM-UA multicriteria global optimization algorithm as well as the local optimization algorithm BC-DFO that is considered as a computational cost saving alternative. First, to reduce the computational cost of the calibration procedure, each spatially distributed parameter (Manning coefficient, river width and river depth) is corrupted through the multiplication of a spatially uniform factor that is the only factor optimized. In this case, it is shown that, when the measurement errors are small, the true water heights and discharges are easily retrieved. Because of equifinality, the true parameters are not always identified. A spatial correction of the model parameters is then investigated and the domain is divided into 4 regions

  10. 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

  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. An Intensive Study of Aerosol Optical Properties in the Outflow of the Manaus Urban Plume, in Central Amazon

    Science.gov (United States)

    Artaxo, P.; Cirino, G. G.; Brito, J.; Rizzo, L. V.; Barbosa, H. M.; Carbone, S.; Holanda, B. A.; Souza, R. A. F. D.; Tota, J.; Martin, S. T.

    2015-12-01

    In this study, one year of ground-based observations of aerosol optical properties from a site impacted by urban emissions in Central Amazon of Brazil are assessed as part of results from GoAmazon2014/5 experiment. The aerosol absorption (σa) and scattering (σs) coefficients, as well as single scattering albedo (SSA) are analyzed to aid in characterizing Manaus' urban aerosol at GoAmazon T2 site. There is a distinct diurnal variation for (σa) it was mainly attributed to the severe emission of particulate pollutants and black carbon during the morning and evening traffic rush hours. The decrease of (σa) nearly at noon (12:00-14:00 LT) was a result of strong atmospheric mixing and dilution due to the elevated height of atmospheric planetary boundary layer (PBL). After sunset (18:00 LT), the formation of stable nocturnal PBL even in atmospheric inversion led to a low atmospheric diffusion ability to aerosols and thus relatively high (σa) and (σs) throughout the night. Indeed, it was observed a strong dependence on local wind confirmed by simulated back trajectories in all two seasons. Overall, the wind dependence results provide valuable information about the locations of aerosol pollution sources and suggest that the air pollution in dry season is a regional problem but in the wet season it is mainly affected by local urban emissions. We have also seen an interesting difference in variability of (σs) and (σa) during 8:00-13:00 LT in wet season. A clear decrease was observed for (σa), while a smooth increase during 11:00-13:00 LT was presented for (σs). This is possibly a consequence of secondary aerosol production. (σa) is controlled to a large degree by primary aerosols such as black carbon that are emitted directly from pollution sources like vehicles, while (σs) is related to secondary aerosols such as sulfate and nitrate that contribute the most to light scattering. SSA was relatively low around 7:00-08:00 LT, which reflected that (σa) increased more

  13. Slope instability in the Bastardo Basin (Umbria, Central Italy) ? The landslide of Barattano

    OpenAIRE

    Cencetti, C.; Conversini, P.

    2003-01-01

    The Bastardo Basin is one of the classics Apenninic intermontane basins of central Italy. They are en-closed tectonic basins (graben and semigraben) with high anthropization, but with high vulnerability, too (seismic, hydrogeological and geomorphological). The paper concerns some aspects about slope instability in the Bastardo Basin as part of a wider research, which aims to actually define the characteristics of the liability to landslides of the Apenninic intermontane basins. In par...

  14. Use of immunoradiometric assays employing monoclonal antibodies or synthetic peptides for the study of malaria transmission and immunity in migrant population of endemic areas in the Amazon Basin

    International Nuclear Information System (INIS)

    Immunoradiometric assays (IRMA) and immunofluorence tests were used in combination with entomological techniques to study malaria epidemiology in areas in the Amazon Basin where non-immune migrant individuals have settled in recent years. Anopheles darlingi was found to be the most important vector accounting for 77% of the anophelines positive for sporozoites by the IRMA. The prevalence of anti-sporozoite and anti-blood stage antibodies was low and decreased with time after the last episode of malaria. Anti-sporozoite antibodies did not indicate immune status of the individual but may reflect malaria transmission. (author). 9 refs, 4 tabs

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

    OpenAIRE

    I. Trebs; Meixner, F. X.; J. Slanina; Otjes, R.; P. Jongejan; Andreae, M. O.

    2004-01-01

    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 S...

  16. An unusual, dwarf new species of Neotropical freshwater stingray, Plesiotrygon nana sp. nov., from the upper and mid Amazon basin: the second species of Plesiotrygon (Chondrichthyes: Potamotrygonidae)

    OpenAIRE

    Marcelo R. de Carvalho; Maíra P. Ragno

    2011-01-01

    A new species of the relatively poorly known Neotropical freshwater stingray genus Plesiotrygon Rosa, Castello & Thorson, 1987 is described from the main channel and smaller tributaries (Ríos Itaya and Pachitea) of the upper Amazon basin in Peru. The first specimen to be collected, however, was from much farther east in Rio Solimões in 1996, just down-river from Rio Purus (specimen unavailable for this study). Plesiotrygon nana sp. nov., is a very distinctive and unusually small species of fr...

  17. Paleogene Sediment Character of Mountain Front Central Sumatra Basin

    Directory of Open Access Journals (Sweden)

    P. A. Suandhi

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v8i3.164The SE-NW trending Mountain Front of Central Sumatra Basin is located in the southern part of the basin. The Mountain Front is elongated parallel to the Bukit Barisan Mountain, extending from the Regencies of North Padang Lawas (Gunung Tua in the northwest, Rokan Hulu, Kampar, Kuantan Singingi, and Inderagiri Hulu Regency in the southeast. The Palaeogene sediments also represent potential exploration objectives in Central Sumatra Basin, especially in the mountain front area. Limited detailed Palaeogene sedimentology information cause difficulties in hydrocarbon exploration in this area. Latest age information and attractive sediment characters based on recent geological fieldwork (by chaining method infer Palaeogene sediment potential of the area. The Palaeogene sedimentary rock of the mountain front is elongated from northwest to southeast. Thickness of the sedimentary unit varies between 240 - 900 m. Palynology samples collected recently indicate that the oldest sedimentary unit is Middle Eocene and the youngest one is Late Oligocene. This latest age information will certainly cause significant changes to the existing surface geological map of the mountain front area. Generally, the Palaeogene sediments of the mountain front area are syn-rift sediments. The lower part of the Palaeogene deposit consists of fluvial facies of alluvial fan and braided river facies sediments. The middle part consists of fluvial meandering facies, lacustrine delta facies, and turbidity lacustrine facies sediments. The upper part consists of fluvial braided facies and transitional marine facies sediments. Volcanism in the area is detected from the occurrence of volcanic material as lithic material and spotted bentonite layers in the middle part of the mountain front area. Late rifting phase is indicated by the presence of transitional marine facies in the upper part of the Palaeogene sediments.

  18. The Floating Forest: Traditional Knowledge and Use of Matupá Vegetation Islands by Riverine Peoples of the Central Amazon

    Science.gov (United States)

    de Freitas, Carolina T.; Shepard, Glenn H.; Piedade, Maria T. F.

    2015-01-01

    Matupás are floating vegetation islands found in floodplain lakes of the central Brazilian Amazon. They form initially from the agglomeration of aquatic vegetation, and through time can accumulate a substrate of organic matter sufficient to grow forest patches of several hectares in area and up to 12 m in height. There is little published information on matupás despite their singular characteristics and importance to local fauna and people. In this study we document the traditional ecological knowledge of riverine populations who live near and interact with matupás. We expected that their knowledge, acquired through long term observations and use in different stages of the matupá life cycle, could help clarify various aspects about the ecology and natural history of these islands that field biologists may not have had the opportunity to observe. Research was carried out in five riverine communities of the Amanã Sustainable Development Reserve (Brazil). Semi-structured interviews were conducted with 45 inhabitants in order to register local understandings of how matupás are formed, biotic/abiotic factors related to their occurrence, the plants and animals that occur on them, their ecological relevance, and local uses. Local people elucidated several little-known aspects about matupá ecology, especially regarding the importance of seasonal dynamics of high/low water for matupás formation and the relevance of these islands for fish populations. Soil from matupás is especially fertile and is frequently gathered for use in vegetable gardens. In some cases, crops are planted directly onto matupás, representing an incipient agricultural experiment that was previously undocumented in the Amazon. Matupás are also considered a strategic habitat for fishing, mainly for arapaima (Arapaima gigas). The systematic study of traditional ecological knowledge proved to be an important tool for understanding this little-known Amazonian landscape. PMID:25837281

  19. The floating forest: traditional knowledge and use of matupa vegetation islands by riverine peoples of the central Amazon.

    Directory of Open Access Journals (Sweden)

    Carolina T de Freitas

    Full Text Available Matupás are floating vegetation islands found in floodplain lakes of the central Brazilian Amazon. They form initially from the agglomeration of aquatic vegetation, and through time can accumulate a substrate of organic matter sufficient to grow forest patches of several hectares in area and up to 12 m in height. There is little published information on matupás despite their singular characteristics and importance to local fauna and people. In this study we document the traditional ecological knowledge of riverine populations who live near and interact with matupás. We expected that their knowledge, acquired through long term observations and use in different stages of the matupá life cycle, could help clarify various aspects about the ecology and natural history of these islands that field biologists may not have had the opportunity to observe. Research was carried out in five riverine communities of the Amanã Sustainable Development Reserve (Brazil. Semi-structured interviews were conducted with 45 inhabitants in order to register local understandings of how matupás are formed, biotic/abiotic factors related to their occurrence, the plants and animals that occur on them, their ecological relevance, and local uses. Local people elucidated several little-known aspects about matupá ecology, especially regarding the importance of seasonal dynamics of high/low water for matupás formation and the relevance of these islands for fish populations. Soil from matupás is especially fertile and is frequently gathered for use in vegetable gardens. In some cases, crops are planted directly onto matupás, representing an incipient agricultural experiment that was previously undocumented in the Amazon. Matupás are also considered a strategic habitat for fishing, mainly for arapaima (Arapaima gigas. The systematic study of traditional ecological knowledge proved to be an important tool for understanding this little-known Amazonian landscape.

  20. Relative influence of natural watershed properties and human disturbance on stream solute concentrations in the southwestern Brazilian Amazon basin

    Science.gov (United States)

    Biggs, Trent Wade; Dunne, Thomas; Domingues, Tomas Ferreira; Martinelli, Luiz Antonio

    2002-08-01

    We use a synoptic sampling of stream water to quantify the effect of soil type, rock type, deforestation extent determined by Landsat TM imagery, and urban population density on stream solute concentrations for 60 different watersheds in the dry season and 49 in the wet season in the southwestern Brazilian Amazon basin. Catchment areas range between 18 and 12,500 km2. Soil exchangeable cation content explains most of the variance in stream concentrations of cations, dissolved silicon (Si), and acid neutralizing capacity (ANC) in both forested and deforested basins based on regression analysis (R2 range 0.61-0.81), though the mechanism underlying the relationship is unknown. We use the relationship between soil exchangeable cation content and stream solute concentrations in forested catchments to estimate the predisturbance and postdisturbance signal concentrations of stream solutes for deforested watersheds. Signal concentrations of potassium (K), sodium (Na), and chloride (Cl) increase with deforestation extent for streams on gneiss, granite, and sedimentary rock in both the dry and wet seasons after the effect of soil type has been statistically removed. Sulfate (SO4) signal concentrations increase with deforestation extent in the dry season only. For catchments >40% deforested but with no urban populations, the ratios of disturbed to predisturbance stream concentrations range from 1.2 to 3.1 (K), 0.8 to 2.2 (Na), 0.7 to 2.7 (SO4), and 2.4 to 14.6 (Cl) in the dry season and 1.2 to 2.2 (K) and 0.6 to 3.4 (Cl) in the wet season. Urban population density strongly affects Cl and SO4 concentrations in both seasons and Na concentrations in the dry season; the urban signal comprises 40-58% of the dry season Cl signal and 83-89% of the wet season Cl signal for watersheds with >250 persons per km2. Streams on mica-schist, mafic rock and carbonate shale have higher concentrations of Ca, Mg, Si, and ANC than watersheds on gneiss, granite, tertiary sediments or sandstone for

  1. 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.

  2. The biomass burning aerosol influence on precipitation over the Central Amazon: an observational study

    Directory of Open Access Journals (Sweden)

    W. A. Gonçalves

    2014-07-01

    Full Text Available Understanding the aerosol influence on clouds and precipitation is an important key to reduce uncertainties in simulations of climate change scenarios with regards to deforestation fires. Here, we associate rainfall characteristics obtained by an S-Band radar in the Amazon with in situ measurements of biomass burning aerosols for the entire year of 2009. The most important results were obtained during the dry semester (July–December. The results indicate that the aerosol influence on precipitating systems is modulated by the atmospheric instability degree. For stable atmospheres, the higher the aerosol concentration, the lower the precipitation over the region. On the other hand, for unstable cases, higher concentrations of particulate material are associated with more precipitation, elevated presence of ice and larger rain cells, which suggests an association with long lived systems. The results presented were statistically significant. However, due to the limitation imposed by the dataset used, some important features such as wet scavenging and droplet size distribution need further clarification. Regional climate model simulations in addition with new field campaigns could aggregate information to the aerosol/precipitation relationship.

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

    Directory of Open Access Journals (Sweden)

    F. Langerwisch

    2013-06-01

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

  4. Pollination Requirements and the Foraging Behavior of Potential Pollinators of Cultivated Brazil Nut (Bertholletia excelsa Bonpl.) Trees in Central Amazon Rainforest

    OpenAIRE

    M. C. Cavalcante; F.F Oliveira; Maués, M. M.; B. M. Freitas

    2012-01-01

    This study was carried out with cultivated Brazil nut trees (Bertholletia excelsa Bonpl., Lecythidaceae) in the Central Amazon rainforest, Brazil, aiming to learn about its pollination requirements, to know the floral visitors of Brazil nut flowers, to investigate their foraging behavior and to determine the main floral visitors of this plant species in commercial plantations. Results showed that B. excelsa is predominantly allogamous, but capable of setting fruits by geitonogamy. Nineteen be...

  5. Impacts of stocking on the genetic diversity of Colossoma macropomum in central Amazon, Brazil.

    Science.gov (United States)

    de Queiroz, C A; Sousa, N R; da Silva, G F; Inoue, L A K A

    2016-01-01

    Tambaqui (Colossoma macropomum) is the main fish species farmed on a commercial scale in northern Brazil. In view of the current scenario of Brazilian aquaculture, studies on the genetic improvement and reproductive management of captive tambaqui are crucial in identifying the genetic variability of broodstocks and devising management practices. Genetic diversity of three tambaqui broodstocks in western Amazon was evaluated using molecular markers. Fin samples were collected from 89 fish; 38 from Balbina, 30 from a hatchery in Rio Preto da Eva, and 21 from the experimental farm of the Federal University of Amazonas (UFAM). Ten primers were used for the analysis of diversity and genetic structure. Of the 152 bands produced, 146 were polymorphic. The proportion of polymorphic loci showed little variation among the three stocks. The lowest and highest rates were found in the Rio Preto da Eva (80.92%) and Balbina (85.53%) stocks, respectively. Heterozygosity (H) and Shannon (I) indices were similar among the stocks; the lowest values were found in Balbina (H = 0.279 and I = 0.419), and the highest in UFAM (H = 0.294 and I = 0.439). Following analysis of the genetic structure and relationship, the sample was divided into two groups, with the Balbina stock clearly deviating from the others. The results suggest that, to increase genetic variability, molecular information may be used instead of replacement of wild breeders. The groups characterized here can be used in genetic improvement programs with other tambaqui broodstocks from different areas of South America. PMID:27173205

  6. Slope instability in the Bastardo Basin (Umbria, Central Italy) – The landslide of Barattano

    OpenAIRE

    Cencetti, C.; Conversini, P.

    2002-01-01

    The Bastardo Basin is one of the classics Apenninic intermontane basins of central Italy. They are en-closed tectonic basins (graben and semigraben) with high anthropization, but with high vulnerability, too (seismic, hydrogeological and geomorphological). The paper concerns some aspects about slope instability in the Bastardo Basin as part of a wider research, which aims to actually define the characteristics of the liability to ...

  7. Pull-apart origin of the Satpura Gondwana basin, central India

    Indian Academy of Sciences (India)

    Chandan Chakraborty; Sanjoy Kumar Ghosh

    2005-06-01

    The Gondwana basins of peninsular India are traditionally considered as extensional-rift basins due to the overwhelming evidence of fault-controlled synsedimentary subsidence. These basins indeed originated under a bulk extensional tectonic regime, due to failure of the attenuated crust along pre-existing zones of weakness inherited from Precambrian structural fabrics. However, disposition of the basins and their structural architecture indicate that the kinematics of all the basins cannot be extensional. To maintain kinematic compatibility with other basins as well as the bulk lateral extension, some basins ought to be of strike-slip origin. The disposition, shape and structural architecture of the Satpura basin, central India suggest that the basin could be a pull-apart basin that developed above a releasing jog of a left-stepping strike-slip fault system defined by the Son-Narmada south fault and Tapti north fault in consequence to sinistral displacement along WSW-ENE. Development of a sedimentary basin under the above-mentioned kinematic condition was simulated in model experiments with sandpack. The shape, relative size, stratigraphic and structural architecture of the experimental basin tally with that of the Satpura basin. The experimental results also provide insights into the tectono-sedimentary evolution of the Satpura basin in particular and pull-apart basins in general.

  8. Introduction: Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5)

    Science.gov (United States)

    Martin, S. T.; Artaxo, P.; Machado, L. A. T.; Manzi, A. O.; Souza, R. A. F.; Schumacher, C.; Wang, J.; Andreae, M. O.; Barbosa, H. M. J.; Fan, J.; Fisch, G.; Goldstein, A. H.; Guenther, A.; Jimenez, J. L.; Pöschl, U.; Silva Dias, M. A.; Smith, J. N.; Wendisch, M.

    2016-04-01

    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 correspond to the clean and

  9. Introduction: Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5)

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Scot T.; Artaxo, Paulo; Machado, L.A. T.; Manzi, A.; Souza, Rodrigo A.; Schumacher, Courtney; Wang, J.; Andreae, M. O.; Barbosa, Henrique; Fan, Jiwen; Fisch, G.; Goldstein, Allen H.; Guenther, A.; Jimenez, J. L.; Poschl, U.; Silva Dias, Maria Assuncao F.; Smith, J. N.; Wendisch, Manfred

    2016-04-19

    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 during two 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 Introduction to the GoAmazon2014/5 Special Issue, 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 (G1) observed the atmospheric boundary layer and low clouds, and a high-altitude Gulfstream G550 (HALO) operated in the free troposphere. During the two- 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 G1 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 correspond to the clean and

  10. Effects of biomass-burning-derived aerosols on precipitation and clouds in the Amazon Basin: a satellite-based empirical study

    Science.gov (United States)

    Lin, J. C.; Matsui, T.; Pielke, R. A.; Kummerow, C.

    2006-10-01

    Biomass burning in the Amazon provides strong input of aerosols into the atmosphere, with potential effects on precipitation, cloud properties, and radiative balance. However, few studies to date have systematically examined these effects at the scale of the Amazon Basin, over an entire burning season, using available data sets. We empirically study the relationships of aerosol optical depth (τa) versus rainfall and cloud properties measured from satellites over the entire Brazilian Amazon during the dry, biomass burning seasons (August-October) of 2000 and 2003. Elevated τa was associated with increased rainfall in both 2000 and 2003. With enhanced τa, cloud cover increased significantly, and cloud top temperature/pressure decreased, suggesting higher cloud tops. The cloud droplet effective radius (Re) exhibited minimal growth with cloud height under background levels of τa, while distinct increases in Re at cloud top temperatures below -10°C, indicative of ice formation, were observed with aerosol loading. Although empirical correlations do not unequivocally establish the causal link from aerosols, these results are consistent with previous observational and modeling studies that pointed to dynamical effects from aerosols that invigorate convection, leading to higher clouds, enhanced cloud cover, and stronger rainfall. We speculate that changes in precipitation and cloud properties associated with aerosol loading observed in this study could have important radiative and hydrological effects on the Amazonian climate system. The accelerated forest burning for agricultural land clearing and the resulting enhancements in aerosols and rainfall may even partially account for the observed positive trend in Amazonian precipitation over the past several decades.

  11. A scaling approach to Budyko's framework and the complementary relationship of evapotranspiration in humid environments: case study of the Amazon River basin

    Directory of Open Access Journals (Sweden)

    A. M. Carmona

    2015-10-01

    Full Text Available This paper studies a 3-D generalization of Budyko's framework designed to capture the mutual interdependence among long-term mean actual evapotranspiration (E, potential evapotranspiration (Ep and precipitation (P. For this purpose we use three dimensionless and dependent quantities: Ψ = E/P, Φ = Ep/P and Ω = E/Ep. This 3-D space and its 2-D projections provide an interesting setting to test the physical soundness of Budyko's hypothesis. We demonstrate analytically that Budyko-type equations are unable to capture the physical limit of the relation between Ω and Φ in humid environments, owing to the unfeasibility of Ep/P → 0 at E/Ep = 1. Using data from 146 sub-catchments in the Amazon River basin we overcome this inconsistency by proposing a physically consistent power law: Ψ = k Φe, with k = 0.66, and e = 0.83 (R2 = 0.93. This power law is compared with two other Budyko-type equations. Taking into account the goodness of fits and the ability to comply with the physical limits of the 3-D space, our results show that the power law is better suited to model the coupled water and energy balances within the Amazon River basin. Moreover, k is found to be related to the partitioning of energy via evapotranspiration in terms of Ω. This suggests that our power law implicitly incorporates the complementary relationship of evapotranspiration into the Budyko curve, which is a consequence of the dependent nature of the studied variables within our 3-D space. This scaling approach is also consistent with the asymmetrical nature of the complementary relationship of evapotranspiration. Looking for a physical explanation for the parameters k and e, the inter-annual variability of individual catchments is studied. Evidence of space–time symmetry in Amazonia emerges, since both between-catchment and between-year variability follow the same Budyko curves. Finally, signs of co-evolution of catchments are explored by linking spatial patterns of the power

  12. A scaling approach to Budyko's framework and the complementary relationship of evapotranspiration in humid environments: case study of the Amazon River basin

    Science.gov (United States)

    Carmona, A. M.; Poveda, G.; Sivapalan, M.; Vallejo-Bernal, S. M.; Bustamante, E.

    2016-02-01

    This paper studies a 3-D state space representation of Budyko's framework designed to capture the mutual interdependence among long-term mean actual evapotranspiration (E), potential evapotranspiration (Ep) and precipitation (P). For this purpose we use three dimensionless and dependent quantities: Ψ = E ⁄ P, Φ = Ep ⁄ P and Ω = E ⁄ Ep. This 3-D space and its 2-D projections provide an interesting setting to test the physical soundness of Budyko's hypothesis. We demonstrate analytically that Budyko-type equations are unable to capture the physical limit of the relation between Ω and Φ in humid environments, owing to the unfeasibility of Ep ⁄ P = 0 when E ⁄ Ep → 1. Using data from 146 sub-catchments in the Amazon River basin we overcome this inconsistency by proposing a physically consistent power law: Ψ = kΦe, with k = 0.66, and e = 0.83 (R2 = 0.93). This power law is compared with two other Budyko-type equations. Taking into account the goodness of fits and the ability to comply with the physical limits of the 3-D space, our results show that the power law is better suited to model the coupled water and energy balances within the Amazon River basin. Moreover, k is found to be related to the partitioning of energy via evapotranspiration in terms of Ω. This suggests that our power law implicitly incorporates the complementary relationship of evapotranspiration into the Budyko curve, which is a consequence of the dependent nature of the studied variables within our 3-D space. This scaling approach is also consistent with the asymmetrical nature of the complementary relationship of evapotranspiration. Looking for a physical explanation for the parameters k and e, the inter-annual variability of individual catchments is studied. Evidence of space-time symmetry in Amazonia emerges, since both between-catchment and between-year variability follow the same Budyko curves. Finally, signs of co-evolution of catchments are explored by linking spatial

  13. Digital assessment of northern and central Appalachian basin coals

    Energy Technology Data Exchange (ETDEWEB)

    Ruppert, L.F.; Tewalt, S.J.; Braff, L.J.; Wallack, R.N. [US Geological Survey National Center, Reston, VA (US)

    1999-10-01

    The US Geological Survey (USGS) is currently conducting a coal resource assessment of the coalbeds and zones that are projected to provide the bulk of the nation's resources for the next few decades. The Pittsburgh and Upper Freeport coals are the first two beds in the northern and central Appalachian basin region to undergo fully digital coal assessments. The bed-specific assessments are being carried out in partnership with the state geologic surveys of West Virginia, Ohio, Pennsylvania and Maryland. Comprehensive stratigraphic and geochemical data-bases have been developed for both of the beds. The extent of the bed with mined areas, structure contour, isopach, and overburden thickness maps for the Pittsburgh coal bed have been realised as USGS open-file reports. The articles includes several detailed maps showing the export of the Pittsburgh coalbed, ash yield, sulphur contents and calorific value of the coal by county, structure contours, overburden thickness and isopac lines. 10 figs., 2 tabs.

  14. 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

  15. 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

    2008-01-01

    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.Três novas espécies de Loricaria são descritas provenientes dos canais de grandes rios de águas brancas e pretas da bacia Amazônica brasileira, da bacia do alto rio Negro no sul da Venezuela e das águas claras do baixo rio Tocantins. Loricaria lundbergi é simpátrica com L. spinulifera no baixo rio Negro, mas também é conhecida para o sistema do rio Baria, drenagem do Cassiquiare. Loricaria pumila ocorre no baixo rio Amazonas e baixo rio Tocantins. Loricaria spinulifera e L. pumila diferem de outras Loricaria por apresentarem odont

  16. Effects of partial throughfall exclusion on the phenology of Coussarea racemosa (Rubiaceae) in an east-central Amazon rainforest.

    Science.gov (United States)

    Brando, Paulo; Ray, David; Nepstad, Daniel; Cardinot, Gina; Curran, Lisa M; Oliveira, Rafael

    2006-11-01

    Severe droughts may alter the reproductive phenology of tropical tree species, but our understanding of these effects has been hampered by confounded variation in drought, light and other factors during natural drought events. We used a large-scale experimental reduction of throughfall in an eastern-central Amazon forest to study the phenological response to drought of an abundant subcanopy tree, Coussarea racemosa. We hypothesized that drought would alter the production and the timing of reproduction, as well as the number of viable fruits. The study system comprised two 1-ha plots in the Tapajos National Forest, Para, Brazil: a dry plot where 50% of incoming precipitation (80% throughfall) was diverted from the soil during the six-month wet season beginning in January 2000, and a wet plot that received natural rainfall inputs. Fruit production of C. racemosa was quantified every 15 days using 100 litter traps (0.5 m(2)) in each plot. The production of new leaves and flowers was recorded monthly for C. racemosa individuals. Soil water, pre-dawn leaf water potential and solar radiation were measured to help interpret phenological patterns. Over the approximately 3.5-year period (April 2000 through December 2003), total fruit production remained similar between plots, declining by 12%. In 2003, production was four times higher in both plots than in previous years. In the dry plot, fruit fall shifted 40 and 60 days later into the dry season in 2002 and 2003, respectively. Total fruit fall dry mass production was variable across the study period. Foliage and flower production coincided with peak irradiance early in the dry season until delays in flowering appeared in the dry plot in 2002 and 2003. Plant water stress, through its influence on leaf developmental processes and, perhaps, inhibition of photosynthesis, appears to have altered both the timing of fruit fall and the quality and number of seeds produced. PMID:16955290

  17. Using GRACE total water storage data to constrain the dynamics of surface flow in the Community Land Model in the Amazon and Orinoco basins

    Science.gov (United States)

    de Linage, C.; Lo, M.; Famiglietti, J. S.

    2009-12-01

    The surface water component is a major contributor to total water storage in the Amazon and Orinoco basins in South America. Global models that do not account for surface water routing often show poor agreement with the GRACE total water storage observations. In this study, we aim at constraining the spatial variations in surface flow simulated by the routing scheme of the CLM3.5. Two tests are performed corresponding to different choices for the surface-flow velocity value: a homogeneous-velocity model and a two-velocity model (with an upstream velocity that is larger than the downstream velocity in each river channel). The comparison with the GRACE observations is based on selected modes of a Principal Component Analysis of both data sets in order to take into account the spatio-temporal modes of the total water storage.

  18. Numerical simulation of the diurnal cycle of rainfall in SW Amazon basin during the 1999 rainy season: the role of convective trigger function

    Science.gov (United States)

    e Silva, Cláudio Moisés Santos; de Freitas, Saulo Ribeiro; Gielow, Ralf

    2012-08-01

    In continental areas, the maximum rainfall simulated with the Brazilian developments on the Regional Atmospheric Modeling System (BRAMS) occurs around 4 h earlier than the one observed with rain gauges. This work presents the successful implementation of a new convective trigger function (CTF) in the convective parameterization scheme used in BRAMS that corrects this misfit between model and observations. The importance of the CTF formulation on the diurnal cycle of rainfall over the Amazon Basin is reflected by the following numbers: Over Rondonia (SW Amazonia), the original version of BRAMS simulates the maximum rainfall at 1400 UTC (1000 LST), with the new CTF maximum shifting to 1800 UTC (1400 LST), while the S-band radar rainfall maximum is at 1900 UTC (1500 LST). This is attributed to two factors: (1) the new CTF is now coupled to the sensible and latent heat fluxes at surface; (2) during the early morning, the convective available potential energy is reduced.

  19. Cytogenetic variation of repetitive DNA elements in Hoplias malabaricus (Characiformes - Erythrinidae from white, black and clear water rivers of the Amazon basin

    Directory of Open Access Journals (Sweden)

    Fabíola Araújo dos Santos

    2016-03-01

    Full Text Available Abstract Hoplias malabaricus is a common fish species occurring in white, black and clear water rivers of the Amazon basin. Its large distribution across distinct aquatic environments can pose stressful conditions for dispersal and creates possibilities for the emergence of local adaptive profiles. We investigated the chromosomal localization of repetitive DNA markers (constitutive heterochromatin, rDNA and the transposable element REX-3 in populations from the Amazonas river (white water, the Negro river (black water and the Tapajós river (clear water, in order to address the variation/association of cytogenomic features and environmental conditions. We found a conserved karyotypic macrostructure with a diploid number of 40 chromosomes (20 metacentrics + 20 submetacentrics in all the samples. Heteromorphism in pair 14 was detected as evidence for the initial differentiation of an XX/XY system. Minor differences detected in the amount of repetitive DNA markers are interpreted as possible signatures of local adaptations to distinct aquatic environments.

  20. Cytogenetic variation of repetitive DNA elements in Hoplias malabaricus (Characiformes - Erythrinidae) from white, black and clear water rivers of the Amazon basin.

    Science.gov (United States)

    Santos, Fabíola Araújo Dos; Marques, Diego Ferreira; Terencio, Maria Leandra; Feldberg, Eliana; Rodrigues, Luís Reginaldo R

    2016-03-01

    Hoplias malabaricus is a common fish species occurring in white, black and clear water rivers of the Amazon basin. Its large distribution across distinct aquatic environments can pose stressful conditions for dispersal and creates possibilities for the emergence of local adaptive profiles. We investigated the chromosomal localization of repetitive DNA markers (constitutive heterochromatin, rDNA and the transposable element REX-3) in populations from the Amazonas river (white water), the Negro river (black water) and the Tapajós river (clear water), in order to address the variation/association of cytogenomic features and environmental conditions. We found a conserved karyotypic macrostructure with a diploid number of 40 chromosomes (20 metacentrics + 20 submetacentrics) in all the samples. Heteromorphism in pair 14 was detected as evidence for the initial differentiation of an XX/XY system. Minor differences detected in the amount of repetitive DNA markers are interpreted as possible signatures of local adaptations to distinct aquatic environments. PMID:27007897

  1. Impacts of satellite-based precipitation datasets on rainfall-runoff modeling of the Western Amazon basin of Peru and Ecuador

    Science.gov (United States)

    Zubieta, Ricardo; Getirana, Augusto; Espinoza, Jhan Carlo; Lavado, Waldo

    2015-09-01

    Satellites are an alternative source of rainfall data used as input to hydrological models in poorly gauged or ungauged regions. They are also useful in regions with highly heterogeneous precipitation, such as the tropical Andes. This paper evaluates three satellite precipitation datasets (TMPA, CMORPH, PERSIANN), as well as a dataset based only on rain gauge data (HYBAM), and their impacts on the water balance of the Western Amazon basin, a region where hydrological modeling and hydrological forecasting are poorly developed. These datasets were used as inputs in the MGB-IPH hydrological model to simulate streamflows for the 2003-2009 period. The impacts of precipitation on model parameterization and outputs were evaluated in two calibration experiments. In Experiment 1, parameter sets were separately defined for each catchment; in Experiment 2, a single parameter set was defined for the entire basin. TMPA shows overestimated precipitation over the northern region, while CMORPH and PERSIANN significantly underestimate rainfall in the same that region and along the Andes. TMPA and CMORPH lead to similar estimates of mean evapotranspiration (∼2 mm/day) for different regions along the entire basin, while PERSIANN is the least accurate (∼0.5 mm/day). Overall, better scores for streamflow simulations are obtained with Experiment 1 forced by HYBAM and TMPA. Nevertheless, results using the three satellite datasets indicate inter-basin differences, low performance in the northern and high in the southern regions. Low model performances are mainly related to scale issues and forcing errors in small basins over regions that present very low rainfall seasonality.

  2. Fate of nitrogen fertilizers labelled with 15 N in two soil samples of Central Amazon, Brazil

    International Nuclear Information System (INIS)

    The efficiency of two nitrogen fertilizers, ammonium sulphate and urea, labelled with 15 N, in two major Central-Amazonian soils (Yellow Latosol an Oxisol and Red-Yellow Podzolic - an Ultisol), was studied in greenhouse experiments in Nancy, France, 1992. Italian rye-grass (Lolium multiflorum L.) was used as the test plant. Rye-grass nitrogen uptake of ammonium sulphate ranged from 44 tp 49%, and of urea from 60 to 70%. Immobilization and losses of nitrogen were dependent on the fertilizer type. Microbial nitrogen immobilization was higher in the presence of urea, while losses were higher with ammonium sulphate. Since losses of nitrogen fertilizers from leaching were practically nil under the experimental conditions, they might have occurred mainly through gaseous form. (author)

  3. Studies of palaeovegetation changes in the Central Amazon by carbon isotopes (12C, 13C, 14C) of soil organic matter

    International Nuclear Information System (INIS)

    The paper presents carbon isotope data δ13C and 14C on soil organic matter collected along an ecosystem transect in southern Amazon state, north-central Amazon region, that includes three distinct vegetation communities: savannah (Campos de Humaita), a savannah-forest transition and forest (Manaus). The study sites are located along road BR 319. Botanical identification and 13C analysis of modern vegetation in the savannah and forest sites indicate that most of the vegetation is C3 plants, although a few C4 plants are present at Campos de Humaita. The 13C and 14C data for soil organic matter in the Humaita region show that significant vegetation changes have occurred in the past, probably associated with climatic changes. During the early Holocene, forest vegetation extended throughout the study region, including areas occupied today by savannah vegetation. Savannah vegetation expanded at least 2 km into the modern forest ecotone during the middle Holocene, suggesting drier conditions. The last approximately 1000 years appear to indicate a recent expansion of forest vegetation, reflecting a return to a more moist climate. The study illustrates that the transition area between forest and savannah vegetation is quite sensitive to climatic changes, and this region should be the focus of more extensive research related to past climate and vegetation dynamics in the Amazon region. (author)

  4. On the origin of the Southern Permian Basin, Central Europe

    OpenAIRE

    J.-D. van Wees; Stephenson, R.A.; Ziegler, P. A.; Ulf Bayer; McCann, T; R. Dadlez; Gaupp, R; M. Narkiewicz; F. Bitzer; Scheck, M.;  

    2000-01-01

    A detailed study of the structural and stratigraphic evolution of the Southern Permian Basin during latest Carboniferous to Early Jurassic times, supported by quantitative subsidence analyses and forward basin modelling for 25 wells, leads us to modify the conventional model for the Rotliegend-Zechstein development of this basin. The Late Permian-Early Jurassic tectonic subsidence curves are typical for a Permian to Early Triassic extensional stage that is followed by thermal subsidence. Howe...

  5. The extreme 2014 flood in south-western Amazon basin: the role of tropical-subtropical South Atlantic SST gradient

    International Nuclear Information System (INIS)

    Unprecedented wet conditions are reported in the 2014 summer (December–March) in South-western Amazon, with rainfall about 100% above normal. Discharge in the Madeira River (the main southern Amazon tributary) has been 74% higher than normal (58 000 m3 s−1) at Porto Velho and 380% (25 000 m3 s−1) at Rurrenabaque, at the exit of the Andes in summer, while levels of the Rio Negro at Manaus were 29.47 m in June 2014, corresponding to the fifth highest record during the 113 years record of the Rio Negro. While previous floods in Amazonia have been related to La Niña and/or warmer than normal tropical South Atlantic, the 2014 rainfall and flood anomalies are associated with warm condition in the western Pacific-Indian Ocean and with an exceptionally warm Subtropical South Atlantic. Our results suggest that the tropical and subtropical South Atlantic SST gradient is a main driver for moisture transport from the Atlantic toward south-western Amazon, and this became exceptionally intense during summer of 2014. (letter)

  6. Cenozoic tectonics of the Tuz Gölü Basin (Central Anatolian Plateau, Turkey)

    OpenAIRE

    FERNÁNDEZ-BLANCO, David; BERTOTTI, Giovanni; ÇİNER, T. Attila

    2013-01-01

    We present a new 3D geologic model for the architecture and Cenozoic tectonic evolution of the Tuz Gölü Basin, a major sedimentary basin in the Central Anatolian orogenic plateau. This model is grounded on 7 depth-converted seismic reflection profiles in combination with the analysis of backstripped subsidence curves, isochore maps, and a palinspastically restored cross-section. Two stages of basin formation are detected during Cenozoic times. During the Palaeogene, around 2 km of basement su...

  7. Assimilating in situ and radar altimetry data into a large-scale hydrologic-hydrodynamic model for streamflow forecast in the Amazon River basin

    Science.gov (United States)

    Paiva, R. C.; Collischonn, W.; Bonnet, M.; Goncalves, L.; Getirana, A.; Calmant, S.

    2012-12-01

    Large-scale hydrological models and forecast systems may be important tools to reduce the vulnerability of local population in places such as the Amazon River basin, where extreme hydrological events have occurred in the past few years. Due to the size of the basin and the slow speed of movement of its floods, uncertainty on model initial conditions (ICs) may play an important role for discharge forecasts using large scale hydrological models, even for relatively large lead times (~ 1 to 3 months). Data assimilation (DA) methods may provide an interesting way of merging both in situ and newly remotely sensed observations with models to estimate optimal ICs. We present the development and evaluation of a data assimilation framework for both gauged and radar altimetry based discharge and water levels into a large scale hydrological-hydrodynamic model of the Amazon River basin. We also explore the usefulness of such system to provide streamflow forecasts when forced by past climate and based mostly on model initial conditions. This work is in the context of recent developments of techniques for integrating information from models and remotely sensed data, and also of regional/global hydrological forecast systems including poorly gauged basins. We use the conceptual and physically based MGB-IPH model. The model uses the Penman Monteith for evapotranspiration and the Moore and Clarke model for soil water storage. River dynamics is simulated using full Saint-Venant equations and a simple floodplain storage model. The model was forced using satellite-derived daily rainfall (TRMM 3B42). We implemented a DA scheme based on the Ensemble Kalman Filter (EnKF) capable of assimilating three types of data: (1) discharge observations; (2) water levels provided by the ENVISAT radar altimeter; and (3) discharge estimated from radar altimetry. All state variables of the hydrological model were updated at each analyses time step. Model state variables errors were generated by

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

    Digital Repository Service at National Institute of Oceanography (India)

    ShyamPrasad, M.; Sudhakar, M.

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

  9. Categories used to classify the basin-fill deposits in the Central Valley

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital dataset contains the categories used to classify the basin-fill deposits in the Central Valley as either coarse-grained or fine-grained deposits. This...

  10. Variation in size, morphology and chemical composition of polymetallic nodules from the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.; Karisiddaiah, S.M.; Parthiban, G.

    Chemical composition of 613 polymetallic nodules from 150 stations in the Central Indian Ocean Basin (CIOB) are determined and variations in Mn, Fe, Cu, Ni, Co, Zn and moisture content are studied with respect to their size and surface texture...

  11. Diagenetic remobilization of rare earth elements in a sediment core from the central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N.; Banakar, V.K.

    Rare earth elements (REE) distribution in a 36 cm long sediment box core from the Central Indian Basin is studied. REE concentration is generally higher in the upper oxic zone than in intermediate suboxic zone suggesting REE diffusion upwards...

  12. Benthic disturbance and monitoring experiment in the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, R.; Nath, B.N.

    Environmental impact assessment studies for deep-sea manganese nodule mining have been initiated in the Central indian Ocean Basin since 1995. As a part of the first phase for collecting the benthic baseline data, echosounding, subbottom profiling...

  13. Changes in geotechnical properties of sediments from the Central Indian Basin induced by disturbance experiment

    Digital Repository Service at National Institute of Oceanography (India)

    Khadge, N.H.

    During the Indian Deep-sea Environment Experiment (INDEX) conducted in the Central Indian Basin to simulate nodule mining activity, the sediments were physically disturbed, lifted from the seafloor, and then redeposited to study the effects...

  14. Benthic disturbance and impact experiments in the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, R.; Nath, B.N.; Valsangkar, A.B.; Parthiban, G.; Sivakholundu, K.M.; Walker, G.A.

    As a part of the Environmental Impact Assessment studies for nodule mining, a long-term program has been initiated in the Central Indian Basin. Multidisciplinary studies on geological, biological, physical and chemical parameters were carried out...

  15. Recovery of deep-sea meiofauna after artificial disturbance in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Goltekar, N.R.; Gonsalves, S.; Ansari, Z.A.

    -1 1 Recovery of Deep-sea Meiofauna after Artificial Disturbance in the Central Indian Basin INGOLE B.S*., R. GOLTEKAR, S. GONSALVES and Z. A. ANSARI Biological Oceanography Division, National Institute of Oceanography, Dona Paula, Goa; 403004...

  16. Quantitative radiolarian assemblages in surface sediments from the central Indian Basin and their paleomonsoonal significance

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, S.M.

    The percentage data of 47 radiolarian coarser taxonomic groups in the surface sediments from the central Indian Basin was subjected to cluster and factor analyses. The R-mode cluster analysis resulted in 3 dominant clusters which represent surface...

  17. Physical properties of a sediment core from the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Khadge, N.H.

    A box core of 7.5 m was collected from the Central Indian Basin for the purpose of geotechnical studies and depthwise variation of physical properties and clay mineralogy. Water content, Atterberg limits, specific gravity are measured at regular...

  18. Marine mineral resources of the Central Indian Basin: Ferromanganese nodules and crusts

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, P.S.; Nair, R.R.

    The morphology, mineralogy and composition of ferromanganese nodules and crusts from the Central Indian Basin and southwestern flank of the Charlsberg Ridge have been characterized from the analyses of data and samples collected at more than 2000...

  19. Petrology of seamounts in the Central Indian Ocean Basin: Evidence for near-axis origin

    Digital Repository Service at National Institute of Oceanography (India)

    Mukhopadhyay, R.; Batiza, R.; Iyer, S.D.

    ; and Caribbean Basin, Atlantic Ocean (Castillo et al. 1985) and North Central Indian Ocean (Y. Neprochnov personal communication 1995). Information on seamount generation in the Indian Ocean is generally lacking. To test the relation between kinematics...

  20. New ichthyoliths from ferromanganese crusts and nodules from the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Gupta, S.M.

    Ferromanganese encrusted hardgrounds, their intraclasts and the nuclei of manganese nodules collected from the Central Indian Ocean basin have yielded plentiful numbers of ichthyoliths. Forty well-knon ichthyoliths, one new type and 35 new subtypes...

  1. How many more dams in the Amazon?

    International Nuclear Information System (INIS)

    The Amazon watershed harbors a megadiversity of terrestrial and aquatic plants and animals. Mechanisms that sustain this biodiversity are the water level fluctuations the fluvial dynamics and the intense gene flux due to permanent integration of climatological, geomorphological and biological components of the system. The construction of hydroelectric reservoirs to support economic development of Brazil and other countries that share the Amazon basin will interfere with the ecological dynamics of this ecosystem changing the hydrological, hydrosocial and fundamental processes. Furthermore the construction of Andean reservoirs can disrupt the connectivity with the lower Amazon ecosystem. Principles of ecohydrologies, ecological engineering and preservation of key river basins, have to be applied in order to optimize energy production and promote conservation practices. Long term planning and integration of countries that share the Amazon basin is a strategic decision to control and develop the hydropower exploitation in the region. - Highlights: • The Amazon basin is an ecosystem of megadiversity. • The demand for energy threatens this ecosystem. • Climate, water, forests and floodplain interacts in the Amazon basin. • Dams in the Amazon basin will impact the hydrological and biological systems. • Ecohydrological principles and ecological engineering technology are necessary

  2. Application of accelerator mass spectrometry on Environmental studies concerning ages of holocene fires in Central amazon forest

    International Nuclear Information System (INIS)

    The Accelerator Mass Spectrometry (AMS) technique was used to determine the radiocarbon age of Holocene fires in forests of the Amazon Region. Most of the ages were found to be within the 1000-1500 years range. These disturbances were probably caused by climatic anomalies, and they have modified the structure and dynamics of the region vegetation

  3. 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)

  4. 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.

  5. 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.

    2008-01-01

    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 ~1,800 km3. 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 de-trended water storage and precipitation anomalies range from ±40 mm. This range is consistent with stream-flow measurements from the region, although the latter are characterized by a stronger annual signal than our residuals, suggesting that runoff and evaporation may act to partially cancel each other.

  6. Fauna de Hymenoptera em Ficus spp. (Moraceae na Amazônia Central, Brasil Fauna of Hymenoptera in Ficus spp. (Moraceae in the Central Amazon, Brazil

    Directory of Open Access Journals (Sweden)

    Alison G. Nazareno

    2007-12-01

    Full Text Available A interação Ficus (Moraceae - vespas de figo é considerada um dos exemplos mais extremos de mutualismo entre planta e inseto. Neste trabalho, descreve-se a fauna de vespas de figo associada a cinco espécies de Ficus na Amazônia Central, considerando alguns aspectos do modo de polinização nas espécies Ficus (Urostigma cremersii, Ficus (Urostigma greiffiana, Ficus (Urostigma mathewsii, Ficus (Urostigma pertusa e Ficus (Pharmacosycea maxima. O estudo foi desenvolvido durante o período de abril a julho de 2004 em Manaus e Presidente Figueiredo, Estado do Amazonas. O número de espécies de vespas de figo por hospedeiro variou de uma a 13. Vespas do gênero Pegoscapus Cameron, 1906, polinizadoras de Ficus (Urostigma spp., apresentam pentes coxais e bolsos torácicos adaptados à coleta e ao transporte de pólen, indicando modo ativo de polinização. No subgênero Pharmacosycea, a polinizadora do gênero Tetrapus Mayr, 1885, não apresenta estrutura morfológica adaptada ao transporte de pólen, condizente com o modo passivo de polinização. Além das vespas de figo, F. (Pharmacosyceae maxima e F. (Urostigma pertusa apresentaram associação com ácaros, formigas (Solenopsis sp., Formicidae, besouros (Staphylinidae e larvas de Diptera e Lepidoptera.The interaction between Ficus (Moraceae and fig wasps is considered one of the most extreme examples of plant-insect mutualism. In the present study, we reported the fig wasp fauna associated with five Ficus species in the Central Amazon, Brazil, and considered some aspects of the pollination mode found in Ficus (Urostigma cremersii, Ficus (Urostigma greiffiana, Ficus (Urostigma mathewsii, Ficus (Urostigma pertusa e Ficus (Pharmacosycea maxima. The study was carried out from April to July 2004, in the cities of Manaus and Presidente Figueiredo (state of Amazonas, Brazil. The number of fig wasp species per host tree varied from one to 13. Wasps of the genus Pegoscapus Cameron, 1906, pollinators of

  7. Isoprene photochemistry over the Amazon rainforest

    Science.gov (United States)

    Liu, Yingjun; Brito, Joel; Dorris, Matthew R.; Rivera-Rios, Jean C.; Seco, Roger; Bates, Kelvin H.; Artaxo, Paulo; Duvoisin, Sergio; Keutsch, Frank N.; Kim, Saewung; Goldstein, Allen H.; Guenther, Alex B.; Manzi, Antonio O.; Souza, Rodrigo A. F.; Springston, Stephen R.; Watson, Thomas B.; McKinney, Karena A.; Martin, Scot T.

    2016-05-01

    Isoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacrolein (MACR). Unimolecular isomerization and bimolecular reactions with organic peroxy radicals are also possible. There is uncertainty about the relative importance of each of these pathways in the atmosphere and possible changes because of anthropogenic pollution. Herein, measurements of ISOPOOH and MVK + MACR concentrations are reported over the central region of the Amazon basin during the wet season. The research site, downwind of an urban region, intercepted both background and polluted air masses during the GoAmazon2014/5 Experiment. Under background conditions, the confidence interval for the ratio of the ISOPOOH concentration to that of MVK + MACR spanned 0.4–0.6. This result implies a ratio of the reaction rate of ISOPOO with HO2 to that with NO of approximately unity. A value of unity is significantly smaller than simulated at present by global chemical transport models for this important, nominally low-NO, forested region of Earth. Under polluted conditions, when the concentrations of reactive nitrogen compounds were high (>1 ppb), ISOPOOH concentrations dropped below the instrumental detection limit (Amazon rainforest.

  8. Water soluble inorganic trace gases and related aerosol compounds in the tropical boundary layer. An analysis based on real time measurements at a pasture site in the Amazon Basin

    OpenAIRE

    I. Trebs

    2005-01-01

    This dissertation investigates the behavior of water-soluble inorganic trace gases and related aerosol species in the tropical boundary layer. Mixing ratios of ammonia (NH3), nitric acid (HNO3), nitrous acid (HONO), hydrochloric acid (HCl), sulfur dioxide (SO;,) and the corresponding water-soluble aerosol species, ammonium (NH,,1), nitrate (NO3 ), nitrite (NO,), chloride (CI) and sulfate (SO,") were measured at a pasture site in the Amazon Basin (Rondónia, Brazil). Sampling was performed from...

  9. Estimation of erosion and sedimentation yield in the Ucayali river basin, a Peruvian tributary of the Amazon River, using ground and satellite methods

    Science.gov (United States)

    Santini, William; Martinez, Jean-Michel; Guyot, Jean-Loup; Espinoza, Raul; Vauchel, Philippe; Lavado, Waldo

    2014-05-01

    Since 2003, the works of HYBAM observatory (www.ore-hybam.org) has allowed to quantify with accuracy, precision and over a long period Amazon's main rivers discharges and sediments loads. In Peru, a network of 8 stations is regularly gauged and managed in association with the national meteorological and Hydrological service (SENAMHI), the UNALM (National Agrological University of La Molina) and the National Water Agency (ANA). Nevertheless, some current processes of erosion and sedimentation in the foreland basins are still little known, both in volumes and in localization. The sedimentary contributions of Andean tributaries could be there considerable, masking a very strong sedimentation in subsidence zones localized between the control points of the HYBAM's network. The development of spatial techniques such as the Altimetry and reflectance measurement allows us today to complete the ground's network: HYBAM's works have allowed establishing a relation between surface concentration and reflectance in Amazonian rivers (Martinez et al., 2009, Espinoza et al., 2012) and reconstituting water levels series (Calmant et al., 2006, 2008). If the difficulty of calibration of these techniques increases towards the upstream, their use can allow a first characterization of the tributaries contributions and sedimentation zones. At world level, erosion and sedimentation yields in the upper Ucayali are exceptional, favored by a marked seasonality in this region (Espinoza et al., 2009, Lavado, 2010, Pépin et al., 2010) and the presence of cells of extreme precipitation ("Hotspots") (Johnson et al., 1976, Espinoza et al, 2009a). The upper Ucayali drainage basin is a Piggyback where the River run with a low slope, parallel to the Andean range, deposing by gravity hundred millions a year of sands, silts and clays. In this work, we thus propose an estimation of sedimentation and erosion yield in the Ucayali river basin using ground and satellite methods.

  10. Structural influences on seismic stratigraphy of Nias forearc basin, west of central Sumatra

    Energy Technology Data Exchange (ETDEWEB)

    Matson, R.G.; Moore, G.F.

    1988-02-01

    The Nias forearc basin is a 250-km long, 100-km wide bathyal depression located between the mainland of west-central Sumatra and the island of Nias. A grid of multichannel reflection seismic data covering the basin and adjacent shelves was used to map Neogene structure and to delineate the Neogene seismic stratigraphy. Six major structural features, including the continental margin, strike-slip faults traversing the forearc, and uplifts within the accretionary wedge, were mapped, while 11 seismic sequences were identified within Neogene reflectors. Positive correlations between the structure and seismic facies distributions indicate structure has influenced subsidence and depositional patterns through the developmental history of the basin. From a developmental standpoint, the Nias forearc basin can be subdivided into two smaller basins, the Singkel basin to the north and the Pini basin to the south. During the Miocene and early Pliocene, distinct facies distributions indicate that these two basins developed independently of each other. Subsidence in the Singkel basis was initiated between two parallel strike-slip faults that traverse the forearc. The geometry of the Pini basin, on the other hand, was controlled by the local character of the continental margin and by the uplift of the developing accretionary wedge. In the late Pliocene, a more unified facies distribution across the study area indicates subsidence of a more regional character and an increased regional structural influence over the entire Nias basin area.

  11. Holocene Environmental Changes from the Rio Curuá Record in the Caxiuanã Region, Eastern Amazon Basin

    Science.gov (United States)

    Behling, Hermann; da Costa, Marcondes Lima

    2000-05-01

    Holocene environments have been reconstructed by multiproxy studies of an 850-cm-long core from Rio Curuá dating to >8000 14C yr B.P. The low-energy river lies in the eastern Amazon rain forest in the Caxiuanã National Forest Reserve, 350 km west of Belém in northern Brazil. Sedimentological, mineralogical, and geochemical dates demonstrate that the deposits correspond to two different environments, sediments of an active river before 8000 14C yr B.P. and later a passive river system. The pollen analytical results indicate four different local and regional Holocene paleoenvironmental periods: (1) a transition to a passive fluvial system and a well-drained terra firme (unflooded upland) Amazon rain forest with very limited development of inundated forests (várzea and igapó) (>7990-7030 14C yr B.P.); (2) a sluggish river with a local Mauritia palm-swamp and similar regional vegetation, as before (7030-5970 14C yr B.P.); (3) a passive river, forming shallow lake conditions and with still-abundant terra firme forest in the study region (5970-2470 14C yr B.P.); and (4) a blocked river with high water levels and marked increase of inundated forests during the last 2470 14C yr B.P. Increased charcoal during this last period suggests the first strong presence of humans in this region. The Atlantic sea level rise was probably the major factor in paleoenvironmental changes, but high water stands might also be due to greater annual rainfall during the late Holocene.

  12. Isotope characterization of the water vapour in the Amazon region

    International Nuclear Information System (INIS)

    Samples of atmospheric moisture and of precipitation have been collected daily at two stations in the Amazon Basin, that is Belem, close to the Atlantic coast, and Manaus, approximately 1200 km from the ocean. The deuterium and oxygen-18 contents have been determined in these samples. The isotopic composition of the atmospheric moisture varies generally in parallel with that of precipitation. The isotopic data show the occurrence of at least three seasons in the hydro-meteorology of the Central Amazon Basin. The period of moderate rains (usually less than 25mm/day) from June to late September show rather constant isotopic values. From October to November significantly more negative delta values occur occasionally, especially at Manaus, which are uncorrelated with events at the other station. The period January-April (occasionally extending from December to May) is characterised by periods with rains extremely depleted in heavy isotopes. In spite of the isothermy of the area and lack of clearcut frontal systems, the data suggest that many of the rainy episodes are related to events imposed on the basin from outside and that only the winter period is predominantly influenced by the internal processes within the basin. Presumably then, winter is the season whose precipitation pattern would be most influenced by any deforestation program in the basin

  13. Tropical forest carbon balance: effects of field- and satellite-based mortality regimes on the dynamics and the spatial structure of Central Amazon forest biomass

    International Nuclear Information System (INIS)

    Debate continues over the adequacy of existing field plots to sufficiently capture Amazon forest dynamics to estimate regional forest carbon balance. Tree mortality dynamics are particularly uncertain due to the difficulty of observing large, infrequent disturbances. A recent paper (Chambers et al 2013 Proc. Natl Acad. Sci. 110 3949–54) reported that Central Amazon plots missed 9–17% of tree mortality, and here we address ‘why’ by elucidating two distinct mortality components: (1) variation in annual landscape-scale average mortality and (2) the frequency distribution of the size of clustered mortality events. Using a stochastic-empirical tree growth model we show that a power law distribution of event size (based on merged plot and satellite data) is required to generate spatial clustering of mortality that is consistent with forest gap observations. We conclude that existing plots do not sufficiently capture losses because their placement, size, and longevity assume spatially random mortality, while mortality is actually distributed among differently sized events (clusters of dead trees) that determine the spatial structure of forest canopies. (paper)

  14. FIRST RECORD OF Alburnus atropatenae (BERG, 1925) (CYPRINIDAE) IN NAMAK BASIN, CENTRAL IRAN

    OpenAIRE

    Somaye Khataminejad; Hamed Mousavi-Sabet; Masud Sattari; Saber Vatandoust

    2013-01-01

    Alburnus atropatenae Berg, 1925 is reported for the first time from the River Ghareh-Chay in the Namak basin, central Iran. Previously, this species has only been reported from the Lake Orumiyeh basin, in northwest Iran. In this report twenty-nine specimens were caught on 8 August 2012. Morphometric and meristic characteristics of the specimens were similar to those reported elsewhere for the species.

  15. FORMATIVE MECHANISM OF AKAISHI MOUNTAINS AND ENREI BASIN IN CENTRAL JAPAN

    Institute of Scientific and Technical Information of China (English)

    Yasu'uchi KUBOTA; Takao YANO

    2001-01-01

    @@ 1 Introduction It is common in mobile belts that uplifting mountains are neighbored by synchronously subsiding basins.The coupling mechanism of such subsidence and uplift is an important target to clarify the dynamics of mobile belts.We investigate the coupled mountain uplift and basin subsidence in the Central Japan highland,the junction of three island arcs (the Northeast Japan,the Southwest Japan and the Izu-Ogasawara arcs).The highland over 3 000 m in height is composed of mountain ranges,plateaus and intramountain basins (Fig.1).

  16. FORMATIVE MECHANISM OF AKAISHI MOUNTAINS AND ENREI BASIN IN CENTRAL JAPAN

    Institute of Scientific and Technical Information of China (English)

    Yasu'uchi; KUBOTA; Takao; YANO

    2001-01-01

    1 Introduction  It is common in mobile belts that uplifting mountains are neighbored by synchronously subsiding basins.The coupling mechanism of such subsidence and uplift is an important target to clarify the dynamics of mobile belts.We investigate the coupled mountain uplift and basin subsidence in the Central Japan highland,the junction of three island arcs (the Northeast Japan,the Southwest Japan and the Izu-Ogasawara arcs).The highland over 3 000 m in height is composed of mountain ranges,plateaus and intramountain basins (Fig.1).……

  17. Oxygen and hydrogen isotope exchange of geopressured thermal water in the central Guanzhong basin

    Institute of Scientific and Technical Information of China (English)

    YU Juan; MA Zhi-yuan; WANG Zhao-wei; LI Wei-liang; SU Yan

    2009-01-01

    Geothermal water of Xi'an and Xianyang in the central Guanzhong basin is typically geopressured thermal water in China. δ18O and δD data of geopressured thermal water in Xi'an and Xianyang, combined with data from the perimeter of the basin, are analyzed to study features of hydrogen and oxygen shifts. The results show that 18O exchange of geothermal water at the pc-rimeter of the basin and in the non-geopressured thermal water in the center of the basin is not evident, while in most of the geo-pressured thermal water in the central basin, in cities such as Xi'an and Xianyang, significant oxygen exchange had taken place as well as hydrogen exchange, suggesting that isotope exchanges would slowly move the geothermal water system towards equilib-rium. Thermal water reservoirs in the central basin have passed through significant water-rock reactions. Moreover, the geothermal reservoir of Xianyang city is relatively much more enclosed than that of Xi'an city. It has been observed that the more enclosed the geological environment of geothermal water is, the more obvious the oxygen shifts are. With the increasing of the depth, residence time, total amounts of thssolute solids and temperatures of geothermal waters, the oxygen exchange accelerates.

  18. Basin formation and inversion of the back-arc, Niigata basin, central Japan: New insight from deep seismic profiling

    Science.gov (United States)

    Sato, Hiroshi; Abe, Susumu; Kawai, Nobuo; Saito, Hideo; Kato, Naoko; Shiraishi, Kazuya; Ishiyama, Tatsuya; Fukasawa, Hikaru; Inaba, Mitsuru

    2010-05-01

    Associated with the opening of the Japan Sea, rift-basins have been developed along the Japan Sea coast of northern Honshu. The Niigata basin, central Japan, is one of the such basins and filled by thick (faulting. Due to thick Neogene sediments, relationship between active faults/folds at near the surface and deep-sited seismogenic source faults is poorly understood. To reveal the crustal structure, in particular geometry of source faults, onshore-offshore integrated deep seismic profiling was undertaken along the two seismic lines in 2008 and 2009. The 2009 Aizu-Sado seismic line is a 135-km-long, onshore-offshore seismic line across Niigata basin and Sado island, which is located in the eastern part of Japan Sea. The 2008 Sanjo-Yahiko seismic line (Sato et al., 2009) is located 20 km south of the seismic line and trending parallel to it. The seismic source was air-gun (3020 cu. inch), four vibroseis trucks and explosives (cables, cable-connected-recording system and offline recorders, forming a maximum 2400 channels receiver array. The basin fill consists of early to middle Miocene volcaniclastic rocks and overlying Neogene sedimentary rocks showing upward coarsening facies deposited under bathyal to fluvial environment. Main features of basin development, such as early Miocene normal faulting, associated with the formation of Japan Sea, and shortening deformation since Pliocene, are well demonstrated on the seismic sections. Particularly, boundary between pre-Tertiary meta-sedimentary rocks and Miocene volcanics were identified by velocity profile deduced by diving wave tomography and it enabled us to identify the geometry of extensional rift-basin. It is very difficult to distinguish meta-sedimentary rocks from volcaniclastic rocks by seismic facies or pattern of reflections. Fault reactivation of Miocene normal faulting to reverse faulting is common style of deformation. The fault reactivation processes of the eastern boundary fault of the Nagaoka plane

  19. 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. PMID:27173830

  20. Correction of Interferometric and Vegetation Biases in the SRTMGL1 Spaceborne DEM with Hydrological Conditioning towards Improved Hydrodynamics Modeling in the Amazon Basin

    Directory of Open Access Journals (Sweden)

    Sebastien Pinel

    2015-12-01

    Full Text Available In the Amazon basin, the recently released SRTM Global 1 arc-second (SRTMGL1 remains the best topographic information for hydrological and hydrodynamic modeling purposes. However, its accuracy is hindered by errors, partly due to vegetation, leading to erroneous simulations. Previous efforts to remove the vegetation signal either did not account for its spatial variability or relied on a single assumed percentage of penetration of the SRTM signal. Here, we propose a systematic approach over an Amazonian floodplain to remove the vegetation signal, addressing its heterogeneity by combining estimates of vegetation height and a land cover map. We improve this approach by interpolating the first results with drainage network, field and altimetry data to obtain a hydrological conditioned DEM. The averaged interferometric and vegetation biases over the forest zone were found to be −2.0 m and 7.4 m, respectively. Comparing the original and corrected DEM, vertical validation against Ground Control Points shows a RMSE reduction of 64%. Flood extent accuracy, controlled against Landsat and JERS-1 images, stresses improvements in low and high water periods (+24% and +18%, respectively. This study also highlights that a ground truth drainage network, as a unique input during the interpolation, achieves reasonable results in terms of flood extent and hydrological characteristics.

  1. The 18O:16O of dissolved oxygen in rivers and lakes in the Amazon Basin: Determining the ratio of respiration to photosynthesis rates in freshwaters

    International Nuclear Information System (INIS)

    The concentration and 18O:16O ratio of dissolved oxygen were measured for 23 rivers and lakes of the Amazon Basin during 1988, 1990, and 1991. With only two exceptions, the rivers and lakes had dissolved oxygen concentrations that were at 20-90% of atmospheric saturation levels. The δ18O of the dissolved oxygen ranged from 15 to 30% (vs. SMOW). The δ18O for the lakes were the lowest at 15-23%. δ18O 18O of the rivers, in contrast, ranged from 24 to 30 per-thousand > 24.2 per-thousand resulted from respiration. Despite this clear difference between the δ18O for rivers and lakes, these water bodies had similar levels of oxygen undersaturation. The δ18O and dissolved oxygen concentrations are used to determine the ratio of community respiration (R) to gross photosynthesis (P) rates. R:P varied between ∼1 and 1.5 for lakes and between 1.5 and 4 for rivers. For all rivers and lakes, the measured δ18O indicated the presence of photosynthetically produced oxygen, with the highest proportion occurring in lakes. The δ18O of dissolved oxygen is a unique tracer of photosynthetic oxygen and provides, through a determination of R:P, a means of quantifying the heterotrophic state of freshwaters. 29 refs., 8 figs., 4 tabs

  2. Slope instability in the Bastardo Basin (Umbria, Central Italy – The landslide of Barattano

    Directory of Open Access Journals (Sweden)

    C. Cencetti

    2003-01-01

    Full Text Available The Bastardo Basin is one of the classics Apenninic intermontane basins of central Italy. They are en-closed tectonic basins (graben and semigraben with high anthropization, but with high vulnerability, too (seismic, hydrogeological and geomorphological. The paper concerns some aspects about slope instability in the Bastardo Basin as part of a wider research, which aims to actually define the characteristics of the liability to landslides of the Apenninic intermontane basins. In particular lithological, stratigraphical and hydrogeological conditions are analysed under which a landslide near village of Barattano has developed. This mass movement, at different times, produced partial or total occlusion of the torrent Puglia. Here geognostic investigations together with laboratory tests and subsequent monitoring of landslide area were carried out.  A back analysis, based on limit equilibrium solutions for the factor of safety of the slope, provided the residual strenght properties of the soil mass along the sliding surface.   The landslide of Barattano is representative of a very frequent situation (in terms of type, factors and causes of the movement, possible development of the movement not only within Bastardo Basin, but in general within Apenninic intermontane basins, too.  The study of landslide and the design of appropriate remedial measures are of great importance in terms of prevention and mitigation of geologic-hydraulic risk in Apenninic intermontane basins.

  3. 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.

  4. Tectonics and sedimentary evolution of the Sandino forearc basin off Nicaragua, Central America

    Science.gov (United States)

    Costa Pisani, P.; Silver, E.; McIntosh, K.; Ahmed, I.; Ranero, C. R.; Taylor, B.

    2003-04-01

    The Sandino basin is the Nicaragua sector of the Central American forearc, where the Cocos plate subducts beneath the Middle America trench. Recently, Ranero et al. have interpreted a seismic section across the margin and proposed a history of formation of the forearc which is constrained by industry drilling in the basin. They suggested a late Cretaceous to Paleocene accretion event, followed by later subduction erosion processes. The margin wedge consists of the ophiolitic Nicoya complex. The seismic units, unconformities and tectonic features record a rich history of both local and regional vertical movements occurring since the Middle Eocene, which are linked to the evolution of the Pacific convergent margin. During June, 2000, 2800 kms of multichannel seismic reflection data were collected on the R/V Ewing off Nicaragua. Analysis of the 240 channels dataset indicates rapid changes along strike in the Sandino basin. The basin is relatively thin in the southern part, thinning quite rapidly southward against the Nicoya complex of the Santa Elena peninsula of Costa Rica. The forearc sediments thickness approaches and locally exceeds 10 kms in the central and northern parts of the Sandino basin. The oldest units (Upper Cretaceous-Middle Eocene) are very thick off northern Nicaragua, with relatively thin middle to late Cenozoic deposits. However, off central Nicaragua the latter units (Middle-Upper Miocene) attain great thicknesses and the older units appear to thin. This pattern suggests a history of successive deepening of the basin from north to south, after the convergent system evolved from accretion to subduction erosion processes. Present efforts are devoted to quantifying this change in development and using it to understand the dynamics of forearc basin evolution offshore of Central America.

  5. Was the 2009 flood the most hazardous or the largest ever recorded in the Amazon ?

    OpenAIRE

    Filizola, N.; Latrubesse, E. M.; Fraizy, Pascal; Souza, R; Guimaraes, V; Guyot, Jean-Loup

    2014-01-01

    Floods are fundamental components of Amazon nature and culture. The large flood of 2009, however, opened a new perspective on hazards and disasters in the Amazon basin. More than 238,000 residents from 38 municipalities were affected by floods along the Amazon River and lower reaches of its tributaries. Never before has a flood in the Amazon produced such a dramatic effect on the local population. The magnitude of the disaster suggested it was the largest recorded Amazon flood since the begin...

  6. 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

  7. Amazon flood wave hydraulics

    Science.gov (United States)

    Trigg, Mark A.; Wilson, Matthew D.; Bates, Paul D.; Horritt, Matthew S.; Alsdorf, Douglas E.; Forsberg, Bruce R.; Vega, Maria C.

    2009-07-01

    SummaryA bathymetric survey of 575 km of the central Amazon River and one of its tributaries, the Purus, are combined with gauged data to characterise the Amazon flood wave, and for hydraulic modelling of the main channel for the period June 1995-March 1997 with the LISFLOOD-FP and HEC-RAS hydraulic models. Our investigations show that the Amazon flood wave is subcritical and diffusive in character and, due to shallow bed slopes, backwater conditions control significant reach lengths and are present for low and high water states. Comparison of the different models shows that it is necessary to include at least the diffusion term in any model, and the RMSE error in predicted water elevation at all cross sections introduced by ignoring the acceleration and advection terms is of the order of 0.02-0.03 m. The use of a wide rectangular channel approximation introduces an error of 0.10-0.15 m on the predicted water levels. Reducing the bathymetry to a simple bed slope and with mean cross section only, introduces an error in the order of 0.5 m. These results show that when compared to the mean annual amplitude of the Amazon flood wave of 11-12 m, water levels are relatively insensitive to the bathymetry of the channel model. The implication for remote sensing studies of the central Amazon channel, such as those proposed with the Surface Water and Ocean Topography mission (SWOT), is that even relatively crude assumptions regarding the channel bathymetry will be valid in order to derive discharge from water surface slope of the main channel, as long as the mean channel area is approximately correct.

  8. Interpretation of magnetotelluric data: Pasco Basin, south central Washington

    International Nuclear Information System (INIS)

    The purpose of this project was to review, evaluate, and interpret magnetotelluric (MT) data collected in support of the Basalt Waste Isolation Project. The integrated interpretation presented is related to regional and site-specific geology and associated borehole, gravity, and magnetic data. The MT interpretation procedure placed strong reliance on computer models based upon the inferred physical parameters of the subsurface materials and their anticipated variability. Much of the MT data is of poor quality by current standards; however, significant qualitative observations can be made. The quantification of these observations, including the procedures and assumption utilized, are discussed in detail. Problems related to ambiguities inherent in the MT method are discussed as related to the Pasco Basin MT data. 117 refs., 77 figs., 3 tabs

  9. Dependence between Ventilation and Climate as recorded with Biomarkers over the last 420,000 years in the Guianas Region (North-western Amazon Basin)

    Science.gov (United States)

    Rama, O.; Lopez-Otalvaro, G.; Martrat, B.; Flores, J.; Sierro, F. J.; Grimalt, J. O.

    2009-12-01

    There is growing evidence that the majority of the Amazon rainforest survived the climatic threshold of the last ice age. This information is crucial given that this region could be currently near its critical resiliency tipping point; thus, minor climate warming, widespread reductions in precipitation and lengthening of the dry season may be sufficient to gradually contribute to the forest dieback and biodiversity loss [Cowling et al., 2004; Lenton et al., 2008; Maslin, 2004]. To contribute to this knowledge, palaeoclimatic oscillations have been identified in this study by using fossil organic compounds synthesized by marine and terrestrial flora and later accumulated on sediment strata (MD03-2616, 7N, 53W, -1233 meters below sea-level) from the Guianas region, closely linked to the Amazon Basin. Different indicators have been considered to continuously reconstruct the climate over the past 420,000 years at centennial scale: average annual sea surface temperatures (SST, Uk’37), productivity of the coccolithophora flora (alken-2-ones), continental vegetation variability (long chain n-alkanes) and changes in oxygenation of the deep-sea floor (ratio between n-alkan-1-ols and n-alkanes). At present, the Guianas region is largely influenced by migration of the intertropical convergence zone (ITCZ), related temperature and wind patterns, together with changes in hydrological conditions, atmospheric and oceanic fronts. Annual SST is 27.7C; two rain seasons and two dry seasons occur. At the core location, surface waters present complex seasonal configuration, while oxygen-enriched and low-salinity Antarctic Intermediate waters (AAIW) flow northward from -700 to -1500 meters depth; the Upper North Atlantic Deep waters circulate southward at greater depths [World Meteo. Org.; Masson & Delecluse, 2001; Arz et al., 2001]. This study reveals that completely different hydrological conditions and much colder climate occurred in the past, e.g. a harsh drop in SST of up to 24C

  10. Availability of water resources in the rio Bermudez micro-basin. Central Region of Costa Rica

    International Nuclear Information System (INIS)

    The Rio Bermudez micro-basin makes up part of the principal hydrological resource area in the Central Region of Costa Rica. For this reason a study was done to determine the availability of hydrological resources in said micro-basin to identify areas with potential water availability problems. A monthly water balance was calculated using land use, geomorphology and climate parameters. From these water balance studies, the amount of available water was calculated and classified into four categories, however, in this micro-basin, only three categories were identified: high, medium and moderate water availability. No areas were identified with low water availability, indicating availability is sufficient; however, there is increasing demand on water resources because over half of the micro-basin area is classified as having moderate water availability. (Author)

  11. Assessing and addressing the re-eutrophication of Lake Erie: central basin hypoxia

    Science.gov (United States)

    Scavia, Donald; Allan, J. David; Arend, Kristin K.; Bartell, Steven; Beletsky, Dmitry; Bosch, Nate S.; Brandt, Stephen B.; Briland, Ruth D.; Daloğlu, Irem; DePinto, Joseph V.; Dolan, David M.; Evans, Mary Anne; Farmer, Troy M.; Goto, Daisuke; Han, Haejin; Höök, Tomas O.; Knight, Roger; Ludsin, Stuart A.; Mason, Doran; Michalak, Anna M.; Richards, R. Peter; Roberts, James J.; Rucinski, Daniel K.; Rutherford, Edward; Schwab, David J.; Sesterhenn, Timothy M.; Zhang, Hongyan; Zhou, Yuntao

    2014-01-01

    Relieving phosphorus loading is a key management tool for controlling Lake Erie eutrophication. During the 1960s and 1970s, increased phosphorus inputs degraded water quality and reduced central basin hypolimnetic oxygen levels which, in turn, eliminated thermal habitat vital to cold-water organisms and contributed to the extirpation of important benthic macroinvertebrate prey species for fishes. In response to load reductions initiated in 1972, Lake Erie responded quickly with reduced water-column phosphorus concentrations, phytoplankton biomass, and bottom-water hypoxia (dissolved oxygen 2) requires cutting total phosphorus loads by 46% from the 2003–2011 average or reducing dissolved reactive phosphorus loads by 78% from the 2005–2011 average. Reductions to these levels are also protective of fish habitat. We provide potential approaches for achieving those new loading targets, and suggest that recent load reduction recommendations focused on western basin cyanobacteria blooms may not be sufficient to reduce central basin hypoxia to 2000 km2.

  12. Volcanic ash and its enigma: A case study from the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N.

    An ash layer occurs between 10-35 cm depth in sediment cores from the Central Indian Ocean basin. Morphology, major, trace and rare earth element composition of glass shards from the ash layer suggest that the Youngest Toba Tuff of ~74 ka from...

  13. Do manganese nodules grow or dissolve after burial? Results from the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N.; Parthiban, G.P.S.

    Fifty buried manganese nodules at different depth intervals were recovered in 12 sediment cores from the Central Indian Ocean Basin (CIOB). A maximum of 15 buried nodules were encountered in one sediment core (AAS-22/GC-07) and the deepest nodule...

  14. Distribution of baroduric, psychrotrophic and culturable nitrifying and denitrifying bacteria in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; PradeepRam, A.S.; Nair, S.; Nath, B.N.; Chandramohan, D.

    The abundance of baroduric, culturable nitrifying and denitrifying bacteria in the deep-sea cores of Central Indian Basin (CIB) at ca 5000 m depth was investigated. Analysis of 8 cores, sampled between 10 degrees 00 minutes S and 75 degrees 55...

  15. AN INTERDISCIPLINARY APPROACH TO RIPARIAN MEADOW CHARACTERIZATION AND PRIORITIZATION, CENTRAL GREAT BASIN

    Science.gov (United States)

    The Great Basin Ecosystem Management Research group has described the hydrological, geophysical, and geomorphic conditions that lead to the formation and maintenance of riparian meadows of central Nevada. Previous work on these systems has focused on understanding a few study mea...

  16. Impacts on surface productivity during sediment dispersal experiment in Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; Nath, B.N.; Ingole, B.S.; Parthiban, G.; Matondkar, S.G.P.; Raghukumar, C.; Khadge, N.H.; Valsangkar, A.B.; Suryanarayana, A.; Jaisankar, S.; Sharma, R.

    (SEDEX) was conducted in Central Indian Basin (CIB). A total of 675 liters of slurry prepared from 225 kg of wet sediment (330 g . l sup(-1)) was discharged on the surface during the experiment. Water samples were collected before and after the discharge...

  17. Distribution of deep-sea benthos in the proposed mining area of Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Ansari, Z.A.

    During the first stage of the project work on the Indian Deep-Sea Environment Experiment (INDEX), the abundance and distribution of deep-sea benthos were surveyed in the Central Indian Basin for the collection of baseline data. The deep...

  18. Slope angle studies from multibeam sonar data on three seamounts in Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Kodagali, V.N.

    is presented here. The slope angle grid can be used to create the slope angle map. Morphology of three seamounts from Central Indian Basin and the slope angle data on them are described. The seamounts are of the heights 1000-1200 m and occupy area up to 300 sq...

  19. Petrological Characteristics and Genesis of the Central Indian Ocean Basin Basalts

    Digital Repository Service at National Institute of Oceanography (India)

    Das, P.; Iyer, S.D.; Hazra, S.

    The Central Indian Ocean Basin (CIOB) basalts are plagioclase-rich, while olivine and pyroxene are very few. The analyses of 41 samples reveal high FeO sup(T) (approx. 10-18 wt percent) and TiO sub(2) (approx. 1.4-2.7 wt percent) indicating a...

  20. Comparison of internal features and microchemistry of ferromanganese crusts from the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.

    SEM/probe analyses of two ferromanganese crusts from the Central Indian Basin, formed on basalt substrate, reveal botryoids and cusps. The botryoids composed of delta-MnOs2, are enriched in Co, and the cusps and laminations with todorokite...

  1. Geological evolution, regional perspectives and hydrocarbon potential of the northwest Phu Khanh Basin, offshore Central Vietnam

    DEFF Research Database (Denmark)

    Fyhn, Michael Bryld Wessel; Nielsen, Lars H.; Boldreel, Lars Ole;

    2009-01-01

      Seismic stratigraphic and structural analyses of the northwest Phu Khanh Basin, offshore Central Vietnam, based on 2-D seismic data, indicate that the initial rifting began during the latest Cretaceous? or Palaeogene controlled by left-lateral transtension along the East Vietnam Boundary Fault ...

  2. Regional variability in occurrence and distribution of polymetallic nodules in the central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A; Rebello, J.M.S.

    Regional scale morphological studies on different-sized polymetallic nodules from the Central Indian Basin show that only 2–5 cm sized nodules have highest occurrence per station (92–94% along latitudes; 88–94% along longitudes). A nodule size shows...

  3. Geotechnical properties of deep-sea sediments from central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Khadge, N.H.

    Physical and geotechnical properties of 2 sediment cores from the nodule rich area of the Central Indian Ocean Basin are studied to know the sediment characteristics. Average water content of sediment from 2 deep-sea cores is 289% with 151...

  4. Preliminary geotechnical properties of deepsea sediments from the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Khadge, N.H.

    Geotechnical properties of the Plio-Pleistocene sediments from nodule bearing area in the Central Indian Basin have been studied to know shear strength and water content variation with depth. It reveals that surface sediments have low (less than 1 k...

  5. Middle Miocene chitons (Polyplacophora from the Slovak part of the Vienna Basin and the Danube Basin (Central Paratethys

    Directory of Open Access Journals (Sweden)

    Ruman Andrej

    2015-12-01

    Full Text Available We describe species-rich chiton assemblages from the Middle Miocene of the Slovak part of the Vienna Basin and the Danube Basin (Central Paratethys. They were found at five localities, including Devínska Nová Ves brickyard, Devínska Nová Ves-Útočnica, Rohožník clay pit, Kúty-45 borehole and Dubová. Thirteen species belong to eight genera from the families Leptochitonidae, Hanleyidae, Callochitonidae, Chitonidae, Tonicellidae and Acanthochitonidae. They occur predominantly in redeposited, moderately-sorted rhodolith-rich or well-sorted bioclastic layers of the Late Badenian age, and belong to lineages that presently inhabit warm-temperate and tropical regions.

  6. Geotechnical properties of siliceous sediments from the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Khadge, N.H.

    COMMUNICATIONS CURRENT SCIENCE, VOL. 82, NO. 3, 10 FEBRUARY 2002 Geotechnical properties of siliceous sediments from the Central Indian B a sin N. H. Khadge National Institute of Oceanography, Dona Paula, Goa 403 004, India Indian Deep - sea... , for baseline data collec - tion. A NW - SE trending strip of 3000 m length and RESEARCH COMMUNICATIONS CURRENT SCIENCE, VOL. 82, NO. 3, 10 FEBRUARY 2002 339 200 m width was selected for carrying out simulated disturbance studies in this area...

  7. Composition of macrobenthos from the central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Pavithran, S.; Ingole, B.S.; Nanajkar, M.; Raghukumar, C.; Nath, B.N.; Valsangkar, A.B.

    nodules (Prasad 2007). However, of the three oceans, the Indian Ocean is the least studied in terms of deep sea fauna. Benthic organisms play an important role as food for large carnivores and some sediment-dwelling forms influence the mixing of organic... distribution; Central Indian Ocean. J. Earth Syst. Sci. 118, No. 6, December 2009, pp. 689–700 © Indian Academy of Sciences 689 690 S Pavithran et al Figure 1. (a) CIOB and (b) depth contours (meters) and box core locations in the CIOB. available organic carbon...

  8. Methanol and isoprene emissions from the fast growing tropical pioneer species Vismia guianensis (Aubl.) Pers. (Hypericaceae) in the central Amazon forest

    Science.gov (United States)

    Jardine, Kolby J.; Jardine, Angela B.; Souza, Vinicius F.; Carneiro, Vilany; Ceron, Joao V.; Gimenez, Bruno O.; Soares, Cilene P.; Durgante, Flavia M.; Higuchi, Niro; Manzi, Antonio O.; Gonçalves, José F. C.; Garcia, Sabrina; Martin, Scot T.; Zorzanelli, Raquel F.; Piva, Luani R.; Chambers, Jeff Q.

    2016-05-01

    Isoprene (Is) emissions by plants represent a loss of carbon and energy resources leading to the initial hypothesis that fast growing pioneer species in secondary tropical forests allocate carbon primarily to growth at the expense of isoprenoid defenses. In this study, we quantified leaf isoprene and methanol emissions from the abundant pantropical pioneer tree species Vismia guianensis and ambient isoprene concentrations above a diverse secondary forest in the central Amazon. As photosynthetically active radiation (PAR) was varied (0 to 3000 µmol m-2 s-1) under standard leaf temperature (30 °C), isoprene emissions from V. guianensis increased without saturation up to 80 nmol m-2 s-1. A nonlinear increase in isoprene emissions with respect to net photosynthesis (Pn) resulted in the fraction of Pn dedicated to isoprene emissions increasing with light intensity (up to 2 % of Pn). Emission responses to temperature under standard light conditions (PAR of 1000 µmol m-2 s-1) resulted in the classic uncoupling of isoprene emissions (Topt, iso > 40 °C) from net photosynthesis (Topt, Pn = 30.0-32.5 °C) with up to 7 % of Pn emitted as isoprene at 40 °C. Under standard environmental conditions of PAR and leaf temperature, young V. guianensis leaves showed high methanol emissions, low Pn, and low isoprene emissions. In contrast, mature leaves showed high Pn, high isoprene emissions, and low methanol emissions, highlighting the differential control of leaf phenology over methanol and isoprene emissions. High daytime ambient isoprene concentrations (11 ppbv) were observed above a secondary Amazon rainforest, suggesting that isoprene emissions are common among neotropical pioneer species. The results are not consistent with the initial hypothesis and support a functional role of methanol during leaf expansion and the establishment of photosynthetic machinery and a protective role of isoprene for photosynthesis during high temperature extremes regularly experienced in

  9. Morphometric characterization of sub-basins in the municipality of Xapuri: subsidies to land management in the Western Amazon

    Directory of Open Access Journals (Sweden)

    Éllen Albuquerque Abud

    2015-04-01

    Full Text Available This work morphometrically characterized watersheds that occur in the municipality of Xapuri and constructed a model that explains the extent of watershed impact and resilience. Emphasis was given to provide a decision-making tool for non-specialists. The study area is located in the State of Acre and has four sub-basins: Alto Acre, Rio Xapuri, Xipamanu and Riozinho do Rola. A cartographic survey was conducted, to include the morphometric characteristics of the area and land use and cover features that resulted in the soil-hydrographic zoning of the municipality. Sub-basins Xapuri, Xipamanu and Riozinho do Rôla revealed drainage densities and orders that indicate low drainage efficiency, while Alto Acre presented high drainage orders (ninth order and densities, contrary the geometric indices and drainage densities, and is considered to have efficient drainage. Considerable alterations in permanent preservation areas occur in the municipality of Xapuri, with conversion to less resilient areas highly sensitive to impacts. The soil-hydrographic zoning assists in visualizing the municipality in a land management context through an ecosystem approach and a qualitative view of the possibilities and weaknesses.

  10. The optical properties of river and floodplain waters in the Amazon River Basin: Implications for satellite-based measurements of suspended particulate matter

    Science.gov (United States)

    Martinez, Jean-Michel; Espinoza-Villar, Raul; Armijos, Elisa; Silva Moreira, Luciane

    2015-07-01

    Satellite images can now be used to assess river sediment discharge, and systematic studies over rivers and lakes are required to support such applications and document the variability of inland water optical properties at the watershed scale. The optical properties of the Amazon Basin waters were analyzed from in situ measurements of the remote sensing reflectance (Rrs) at 279 stations and downwelling diffuse attenuation coefficients (Kd) at 133 stations. Measurements of the apparent optical properties, suspended particulate matter (SPM) contents, and characteristics and colored dissolved organic matter (CDOM) absorption spectra were performed during 16 cruises along the main Amazonian Rivers draining the Andes and for some tributaries. Surface-suspended sediment granulometry and mineralogy showed a stable distribution at the catchment scale, even over large distances and between tributaries. The particle number-size distribution was best described using a segmented distribution with a slope of 2.2 for the fine range (1-15 µm), and the CDOM absorption coefficient at 440 nm varied from 1.8 to 7.9 m-1. Overall, both Rrs and Kd were strongly correlated with SPM, although strong CDOM absorption limited the use of the blue spectrum. Reflectance saturation from blue to red was observed at approximately 100 g m-3, whereas the near-infrared (NIR) wavelength enabled the monitoring of the full SPM range (5-620 g m-3). In contrast, Kd showed no saturation for SPM from green to NIR, and a linear model was calculated. The use of the reflectance ratio was investigated and shown to improve the suspended sediment concentration retrieval performance.

  11. 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.

  12. 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

    Science.gov (United States)

    Lloyd, J.; Domingues, T. F.; Schrodt, F.; Ishida, F. Y.; Feldpausch, T. R.; Saiz, G.; Quesada, C. A.; Schwarz, M.; Torello-Raventos, M.; Gilpin, M.; Marimon, B. S.; Marimon-Junior, B. H.; Ratter, J. A.; Grace, J.; Nardoto, G. B.; Veenendaal, E.; Arroyo, L.; Villarroel, D.; Killeen, T. J.; Steininger, M.; Phillips, O. L.

    2015-11-01

    Sampling along a precipitation gradient in tropical South America extending from ca. 0.8 to 2.0 m a-1, savanna soils had consistently lower exchangeable cation concentrations and higher 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.

  13. Post-partum reproductive efficiency of pure- and cross-bred Zebu cattle under different management and nutritional conditions in the Amazon Basin of Peru

    International Nuclear Information System (INIS)

    The experiments described were carried out by the Research Centre of the Veterinary Institute for Tropical and High Altitude Research (IVITA), at an experimental station located near Pucallpa in the Amazon Basin of Peru. The aim was to study some of the factors affecting reproductive efficiency under field conditions, with special emphasis on the effects of nutrition, body weight, suckling and some adaptation related parameters in pure- and cross-bred Zebu cattle. Progesterone assay was used in combination with clinical examinations to evaluate more precisely the reproductive parameters studied. A long post-partum anoestrus interval was the most important factor limiting reproductive efficiency in pure-bred Zebu animals. The 10 month interval observed under field and experimental conditions was shortened by improving the level of nutrition. However, the first ovulation after parturition was inhibited by free or restricted suckling until weaning took place 8 months post-partum. In contrast, dual purpose cross bred Bos taurus x Bos indicus animals tended to show better reproductive performance when suckling was allowed, the difference being significant when adequate management and feeding were also provided. Body weight at calving and subsequent weight changes during the post-partum period significantly affected the onset of post-partum reproductive function in both pure- and cross-bred Zebu cows. Cross-bred animals with a low body weight at calving remained acyclic for 8 months. On small farms, only 35% of the intervals between artificial insemination services were in the range of 18 to 24 days. Progesterone profiles determined between successive oestrous periods revealed a high frequency of unobserved oestrus. The correlation between rectal palpation of ovarian structures and progesterone concentration was 0.82 and 0.96 in diagnosing luteal and non-luteal structures respectively. The combination of weekly clinical examinations and progesterone determinations gave a

  14. 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.

  15. 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

    2015-05-01

    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 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, 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.

  16. 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

  17. The fate of nitrogen fertilizer added to soy-maize agriculture in the Amazon basin: Quantifying N2O flux and losses to groundwater

    Science.gov (United States)

    Jankowski, K. J.; Neill, C.; Davidson, E. A.; Macedo, M.; Costa, C., Jr.; Galford, G. L.; Coe, M. T.; O'Connell, C.; Brando, P. M.; Lefebvre, P.; Maracahipes, L.; Nunes, D.; McHorney, R.

    2015-12-01

    Deforestation and agricultural intensification are rapidly changing the landscape of southeastern Amazonia. With international pressure to reduce deforestation, many Brazilian farms have opted to intensify agriculture to a system of soybean-maize double cropping, and it has expanded rapidly in the last 10 years. Maize agriculture requires additional nitrogen (N) fertilizers, whose downstream fate is currently unknown. Typical fertilizer application rates range from 30-120 kg N ha-1, and have the potential to introduce large amounts of N to ecosystems of the Amazon basin, which can alter greenhouse gas flux and nutrient transport to groundwater and streams. Little data on the fate of added fertilizers are available in the tropics in general, especially in this critical region of agricultural expansion. Therefore, we established a field-scale experiment to evaluate the fate of N fertilizer on Tanguro Ranch in Mato Grosso, Brazil, a region of rapidly expanding soy-maize double cropping. We measured greenhouse gas fluxes (N2O, CO2, and CH4), soil N content, losses to groundwater, and corn productivity across five levels of fertilizer addition (0-200 kg N ha-1) throughout an entire growing season. We found that N2O flux increased with fertilizer addition, but was only significantly higher at 200 kg N ha-1. Surface soil N content increased after fertilizer addition, but decreased within weeks, and was quickly observed in subsurface soil water. Modeling results that scale these findings to the state of Mato Grosso suggest that this land use transition could create a substantial new source of N2O and CO2 to the atmosphere and has the potential to leach N fertilizer into groundwater and downstream. It is important to maintain forest code policies that minimize these impacts.

  18. Petroleum source rocks of western and central Africa : the examples of the marine Tarfaya Basin, Morocco and the continental Congo Basin, Democratic Republic of Congo

    OpenAIRE

    Sachse, Victoria Frederike

    2011-01-01

    This study comprises newly collected organic geochemical and petrological data on quality, quantity, maturity as well as the depositional environment of various organic matter-rich stratigraphic units in Morocco and the Central Congo Basin, DRC. In addition, 1D modeling was carried out for one locality in northern Morocco (Aït Moussa) and for two wells from the Central Congo Basin to obtain information on burial thermal and maturation history. For the Aït Moussa model, specific bulk kinetic p...

  19. 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

  20. An Atlantic influence on Amazon rainfall

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jin-Ho [University of Maryland, Department of Atmospheric and Oceanic Science, College Park, MD (United States); Zeng, Ning [University of Maryland, Earth System Science Interdisciplinary Center, College Park, MD (United States); University of Maryland, Department of Atmospheric and Oceanic Science, College Park, MD (United States)

    2010-02-15

    Rainfall variability over the Amazon basin has often been linked to variations in Pacific sea surface temperature (SST), and in particular, to the El Nino/Southern Oscillation (ENSO). However, only a fraction of Amazon rainfall variability can be explained by ENSO. Building upon the recent work of Zeng (Environ Res Lett 3:014002, 2008), here we provide further evidence for an influence on Amazon rainfall from the tropical Atlantic Ocean. The strength of the North Atlantic influence is found to be comparable to the better-known Pacific ENSO connection. The tropical South Atlantic Ocean also shows some influence during the wet-to-dry season transition period. The Atlantic influence is through changes in the north-south divergent circulation and the movement of the ITCZ following warm SST. Therefore, it is strongest in the southern part of the Amazon basin during the Amazon's dry season (July-October). In contrast, the ENSO related teleconnection is through anomalous east-west Walker circulation with largely concentrated in the eastern (lower) Amazon. This ENSO connection is seasonally locked to boreal winter. A complication due to the influence of ENSO on Atlantic SST causes an apparent North Atlantic SST lag of Amazon rainfall. Removing ENSO from North Atlantic SST via linear regression resolves this causality problem in that the residual Atlantic variability correlates well and is in phase with the Amazon rainfall. A strong Atlantic influence during boreal summer and autumn is particularly significant in terms of the impact on the hydro-ecosystem which is most vulnerable during the dry season, as highlighted by the severe 2005 Amazon drought. Such findings have implications for both seasonal-interannual climate prediction and understanding the longer-term changes of the Amazon rainforest. (orig.)

  1. Overview of the structural geology and tectonics of the Central Basin Platform, Delaware Basin, and Midland Basin, West Texas and New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Hoak, T. [Kestrel Geoscience, Littleton, CO (United States); Sundberg, K. [Phillips Petroleum Co., Bartlesville, OK (United States); Ortoleva, P. [Indiana Univ., Bloomington, IN (United States)

    1998-12-31

    The structural geology and tectonics of the Permian Basin were investigated using an integrated approach incorporating satellite imagery, aeromagnetics, gravity, seismic, regional subsurface mapping and published literature. The two primary emphases were on: (1) delineating the temporal and spatial evolution of the regional stress state; and (2) calculating the amount of regional shortening or contraction. Secondary objectives included delineation of basement and shallower fault zones, identification of structural style, characterization of fractured zones, analysis of surficial linear features on satellite imagery and their correlation to deeper structures. Gandu Unit, also known as Andector Field at the Ellenburger level and Goldsmith Field at Permian and younger reservoir horizons, is the primary area of interest and lies in the northern part of Ector county. The field trends northwest across the county line into Andrews County. The field(s) are located along an Ellenburger thrust anticline trap on the eastern margin of the Central Basin Platform.

  2. Dinâmica populacional da matrinxã Brycon amazonicus (Characidae na Amazônia Central Population dynamics of matrinxã Brycon amazonicus (Characidae in Central Amazon

    Directory of Open Access Journals (Sweden)

    Leocy C. dos Santos Filho

    2009-06-01

    Full Text Available The matrinxã, Brycon amazonicus (Spix & Agassiz, 1829 is one of the most important fishery resources of the Amazonas state. Its population dynamics in Central Amazon was analyzed based on total landing and biometry data registered in the main landing port of Manaus, between 1994 and 2002. Growth and mortality rates were estimated separately for the rivers Purus, Madeira and Solimões. Differences in size structure and growth curves suggest that different population units exist among these rivers, requiring individualized evaluation and fisheries management strategies. The analysis of the yield per recruit does not indicate overexploitation. However, the highest relative exploitation rate was observed in the Madeira river. The suggested management strategies are related to restrictions to the fishery in the main fishing grounds during the migratory dispersal period, instead of restrictions during reproductive periods.

  3. Age and paleoenvironmental reconstruction of partially remagnetized lacustrine sedimentary rocks (Oligocene Aktoprak basin, central Anatolia, Turkey)

    Science.gov (United States)

    Meijers, Maud J. M.; Strauss, Becky E.; Özkaptan, Murat; Feinberg, Joshua M.; Mulch, Andreas; Whitney, Donna L.; Kaymakçı, Nuretdin

    2016-03-01

    The age and paleoenvironmental record of lacustrine deposits in the Aktoprak basin of south-central Turkey provides information about the evolution of topography, including the timing of development of an orographic rain shadow caused by uplift of the mountain ranges fringing the Central Anatolian Plateau. New magnetostratigraphy-based age estimates, in combination with existing biostratigraphic ages, suggest that the partially remagnetized Kurtulmuş Tepe section of the basin is Chattian (Upper Oligocene). The mean carbon and oxygen stable isotope ratios (δ18O= 24.6 ± 2.0 ‰, δ13C= -4.9 ± 1.1‰) are largely constant through the section and indicative of a subtropical, open freshwater lake. These isotopic values are also similar to those of the Chattian Mut basin to the south, on the Mediterranean side of the modern orographic barrier (Tauride Mountains), and indicate absence of an orographic barrier during Late Oligocene basin deposition. Post-depositional partial remagnetization occurred after tilting of the basin sequence and was mineralogically controlled, affecting grey, carbonate-rich rocks (average %CaCO3= 82), whereas interlayered pink carbonate-poor rocks (average %CaCO3= 38) carry a primary, pretilt magnetization. The pink rocks are rich in clay minerals that may have reduced the permeability of these rocks that carry a primary magnetization, concentrating basinal fluid flow in the carbonate-rich grey layers and leading to the removal and reprecipitation of magnetic minerals. The normal and reverse polarities recorded by the remagnetized rocks suggest that remagnetization occurred over a protracted period of time.

  4. Tectono-climatic implications of Eocene Paratethys regression in the Tajik basin of central Asia

    Science.gov (United States)

    Carrapa, Barbara; DeCelles, Peter G.; Wang, Xin; Clementz, Mark T.; Mancin, Nicoletta; Stoica, Marius; Kraatz, Brian; Meng, Jin; Abdulov, Sherzod; Chen, Fahu

    2015-08-01

    Plate tectonics and eustatic sea-level changes have fundamental effects on paleoenvironmental conditions and bio-ecological changes. The Paratethys Sea was a large marine seaway that connected the Mediterranean Neotethys Ocean with Central Asia during early Cenozoic time. Withdrawal of the Paratethys from central Asia impacted the distribution and composition of terrestrial faunas in the region and has been largely associated with changes in global sea level and climate such as cooling associated with the Eocene/Oligocene transition (EOT). Whereas the regression has been dated in the Tarim basin (China), the pattern and timing of regression in the Tajik basin, 400 km to the west, remain unresolved, precluding a test of current paleogeographic models. Here we date the Paratethys regression in Tajikistan at ca. 39 million years ago (Ma), which is several million years older than the EOT (at ca. 34 Ma) marking the greenhouse to icehouse climate transition of the Cenozoic. Our data also show a restricted, evaporitic marine environment since the middle-late Eocene and establishment of desert like environments after ca. 39 Ma. The overall stratigraphic record from the Tajik basin and southern Tien Shan points to deposition in a foreland basin setting by ca. 40 Ma in response to active tectonic growth of the Pamir-Tibet Mountains at the same time. Combined with the northwestward younging trend of the regression in the region, the Tajik basin record is consistent with northward growth of the Pamir and suggests significant tectonic control on Paratethys regression and paleoenvironmental changes in Central Asia.

  5. Neutrons, radiation and archaeology: a multi analytical case study of incised rim tradition ceramics in Central Amazon; Neutrons, radiacao e arqueologia: estudo de caso multianalitico de ceramicas da tradicao borda incisa na Amazonia Central

    Energy Technology Data Exchange (ETDEWEB)

    Hazenfratz-Marks, Roberto

    2014-07-01

    This thesis is an interdisciplinary archaeometric study involving archaeological ceramic material from two large archaeological sites in Central Amazon, namely Lago Grande and Osvaldo, on the confluence region of Negro and Solimoes rivers. It was tested a hypothesis about the existence of an exchange network between the former inhabitants of those sites, focusing on material and/or technological exchange. That hypothesis has implications for archaeological theories of human occupation of the pre-colonial Central Amazon, which try to relativise the role of ecological difficulties of the tropical forest as a limiting factor for the emergence of social complexity in the region. The physical-chemical characterization of potsherds and clay samples near the sites was carried out by: instrumental neutron activation analysis (INAA) to determine the elemental chemical composition; electron paramagnetic resonance (EPR) to determine the firing temperature; X-ray diffraction (XRD) to determine the mineralogical composition; and dating by optically stimulated luminescence (OSL). Previous studies showed that Osvaldo and Lago Grande were occupied by people which produced pottery classified in the Manacapuru and Paredao phases, subclasses of the Incised Rim Tradition, around the 5-10th and 7-12th centuries BC, respectively. INAA results were analyzed by multivariate statistical methods, whereby two chemical groups of pottery were defined for each archaeological site. Significant variation in firing temperatures and mineralogical composition were not identified for such groups. By integration of the results with archaeological data, the superposition between pairs of chemical groups was interpreted as a correlate of an ancient exchange network, although it was not possible to define if it existed exclusively between Lago Grande and Osvaldo. On the contrary, it was suggested that Lago Grande participated in a more extensive exchange network by comparison of two chemical groups

  6. Seed size influence on germination responses to light and temperature of seven pioneer tree species from the Central Amazon

    Directory of Open Access Journals (Sweden)

    Fabiana F. Aud

    2012-09-01

    Full Text Available In Amazon secondary forests are dominated by pioneer species that typically produce large amounts of small and dormant seeds that are able to form a persistent soil seed bank. Seed dormancy in this group of species is overcome by environmental conditions found in open areas, such as high irradiation or alternating temperatures. Nevertheless, a variety of germination responses to environmental factors is known among pioneers; some of them may germinate in diffuse light or in darkness condition at constant temperature. Seed mass can be considered as one of the factors that promotes this variety. Regarding species with very small seeds, it seems that the trigger for germination is light and for larger seeds temperature alternation may be a more important stimulus. In this study we established a relationship between seed mass and germination response to light and alternating temperature for a group of seven woody pioneer species from the Amazon forest. We found that an increase in seed mass was followed by a decrease in the need for light and an increase in the tolerance to alternating temperatures. Understanding germination strategies may contribute with the knowledge of species coexistence in high diverse environments and also may assist those involved in forest management and restoration.Na Amazônia as florestas secundárias são dominadas por espécies pioneiras que, normalmente, produzem grandes quantidades de sementes pequenas, dormentes e capazes de formar bancos de sementes no solo. A dormência neste grupo de espécies é superada pelas condições ambientais de áreas abertas, como alta irradiação ou alternância de temperaturas. No entanto, uma variedade de respostas de germinação aos fatores ambientais é conhecida entre as pioneiras; algumas germinam em luz difusa ou no escuro sob temperatura constante. Um dos fatores promotores desta variedade é a massa das sementes. Parece que para as espécies com sementes muito pequenas, o est

  7. 137Cs vertical distribution at the deep basins of the North and Central Aegean Sea, Greece

    International Nuclear Information System (INIS)

    Large volume seawater samples were collected for the determination of 137Cs concentration along with depth in the deep basins of North and Central Aegean Sea. The vertical 137Cs distribution showed maximum concentration at the bottom of the basins, while the minimum values corresponded to the intermediate layer, where Levantine water exists. The surface 137Cs activity is found to lie between the two limits and is originated from the Black Sea waters. The typical oceanographic advection–diffusion balance model is modified to a diffusion-settling-decay balance model to better understand the vertical distribution and variation of the 137Cs concentration in the deep basins. In addition, the diffusivity of each basin, as well as the settling speed of particulate 137Cs is also estimated. The results are compared with theoretical approach as well as with previous data. - Highlights: • Three deep basins were studied using 137Cs as a tracer. • Deep waters constitute 137Cs repositories due to deep water formation followed Chernobyl accident. • Diffusivities, as well as particulate 137Cs settling speeds are estimated

  8. Climate change adaptation in a highly urbanized snowmelt dominated basin in Central Chile

    Science.gov (United States)

    Vicuna, S.; Bustos, E.; Merino, P.; Henriquez Dole, L. E.; Jansen, S.; Gil, M.; Ocampo, A.; Poblete, D.; Tosoni, D.; Meza, F. J.; Donoso, G.; Melo, O.

    2015-12-01

    The Maipo river basin holds 40% of Chile's total population and produces almost half of the country's Gross Domestic Product. The basin is located in the semiarid and snowmelt dominated central region of the country and, aside from the typical pressures of growth in developing country basins, the Maipo river basin faces climate change impacts associated with a reduction in total runoff and changes in its seasonality. Surface water is the main water source for human settlements, natural ecosystems, and economic activities including agriculture, mining and hydropower production. In 2012 a research project, called MAPA (Maipo Plan de Adaptacion), began with the objective of articulating a climate variability and climate change adaptation plan for the Maipo river basin. The project engaged at the beginning a group of relevant water and land use stakeholders which allowed for a good representation of critical aspects of an adaptation plan such as the definition of objectives and performance indicators, future land use scenarios, modeling of the different components of the system and design of adaptation strategies. The presentation will highlight the main results of the research project with a special focus on the upper catchments of the basin. These results include the assessment of impacts associated with future climate and land use scenarios on key components of the hydrologic cycle including snowmelt and glacier contribution to runoff and subsequent impacts on water availability for the operation of hydropower facilities, satisfaction of instream (recreation and aquatic ecosystem) uses and provision of water for the city of Santiago (7 million people) and to irrigate more than 100,000 hectares of high value crops. The integrative approach followed in this project including different perspectives on the use of water in the basin provides a good opportunity to test the varying degree of impacts that could be associated with a given future scenario and also understand

  9. Sustainable Transformations of Water Supply Regimes. The Cuvelai-Etosha Basin in Central Northern Namibia.

    OpenAIRE

    Zimmermann, Martin

    2013-01-01

    In this thesis, an interdisciplinary modelling approach for water resources management and its application is presented that is able to deal with socio-technical systems that are characterised by a multiplicity of variables, interdependencies, and actors. The case study area is the Cuvelai-Etosha Basin, which is located in central northern Namibia. Approximately 850,000 people or 40 % of the Namibian population live in this area, which comprises only about 14 % of the country’s area. The regi...

  10. 10Be variation in surficial sediments of the Central Indian Basin

    International Nuclear Information System (INIS)

    Distribution of 10Be in systematically collected (degree x degree interval at 10 to 16 deg. S; 73.5 to 76.5 deg. E) surficial siliceous ooze, siliceous clay and pelagic clay sediments (top 2 cm) from the abyssal Central Indian Basin and the Andaman Sea is used to evaluate sources and to decipher the transport pathways of sediment particles, demarcate sediment depocenters and erosional areas. While 10Be concentrations display a wide variation (0.12-5.56 x 109 atoms g-1) with an average of 3.58 x 109 atoms g-1 in the Central Indian Basin, the values in the Andaman Sea are uniform with an average of 1.49 x 109 atoms g-1. The 10Be/9Be values in the Central Indian Basin sediments range between 0.06 and 2.99 x 10-8 atoms atoms-1 and average to ∼1.56 x 10-8 atoms atoms-1. Correlation of 10Be data with some selected major (Al, Mn, Ti) and trace (Rb and Ba) elements suggest that large part of the isotope has been supplied through direct atmospheric fallout from the water column and minor part from lithogenic detrital flux. Significantly lower 10Be accumulation rates in the Central Indian Basin and an order of magnitude higher in the Andaman Sea sediments compared to the estimated global average production rates indicate removal of the isotopes at the continental margins. Bottom topography seems to exert control on local 10Be variation, where sediments deposited in valleys or topographic depressions contain higher 10Be concentrations in contrast to the probably erosion-dominated areas at the slopes and troughs

  11. Hydrological Modeling in an Ungauged Basin of Central Vietnam Using SWAT Model

    OpenAIRE

    Rafiei Emam, Ammar; Kappas, Martin; Hoang Khanh Nguyen, Linh; Renchin, Tsolmon

    2016-01-01

    Hydrological modeling of ungauged basins which have a high risk of natural hazards (e.g., flooding, droughts) is always imperative for policymakers and stakeholders. The Aluoi district in Hue province is a representative case study in Central Vietnam, as it is under extreme pressure of natural and anthropogenic factors. Flooding, soil erosion and sedimentation are the main hazards in this area, which threaten socio-economic activities not only in this district but also those of the area downs...

  12. Spatio-Temporal Variations and Source Apportionment of Water Pollution in Danjiangkou Reservoir Basin, Central China

    OpenAIRE

    Pan Chen; Lan Li; Hongbin Zhang

    2015-01-01

    Understanding the spatio-temporal variation and the potential source of water pollution could greatly improve our knowledge of human impacts on the environment. In this work, data of 11 water quality indices were collected during 2012–2014 at 10 monitoring sites in the mainstream and major tributaries of the Danjiangkou Reservoir Basin, Central China. The fuzzy comprehensive assessment (FCA), the cluster analysis (CA) and the discriminant analysis (DA) were used to assess the water pollutio...

  13. Hydrovolcanic activity in the Central Indian Ocean Basin. Does nature mimic laboratory experiments?

    Digital Repository Service at National Institute of Oceanography (India)

    Iyer, S.D.; ShyamPrasad, M.; Gupta, S.M.; Charan, S.N.; Mukherjee, A.D.

    ’ ’ National Institute of Oceanography, Dona Paula, Goa 403 004, India b National Geophysical Research Institute, Uppal Road, Hyderabad 500 007, India ’ School of Oceanographic Studies, Department of Geological Sciences, Jadavpur University, Calcutta 700 032... (communicated). 220 S.D. Iyer et al. /Joumai of Volcanology and Geothermal Research 78 (19971209-220 Iyer, S.D., Sudhakar, M., 1993. A new report on the occurrence of zeolitites in the abyssal depths of the Central Indian Basin. Sediment. Geol. 84, 169...

  14. Methane emissions from northern Amazon savanna wetlands and Balbina Reservoir

    Science.gov (United States)

    Kemenes, A.; Belger, L.; Forsberg, B.; Melack, J. M.

    2006-12-01

    To improve estimates of methane emission for the Amazon basin requires information from aquatic environments not represented in the central basin near the Solimoes River, where most of the current data were obtained. We have combined intensive, year-long measurements of methane emission and water levels made in interfluvial wetlands located in the upper Negro basin with calculations of inundation based on a time series of Radarsat synthetic aperature radar images. These grass-dominated savannas emitted methane at an average rate of 18 mg C per m squared per day, a low rate compared to the habitats with floating grasses the occur in the Solimoes floodplains. Reservoirs constructed in the Amazon typically flood forested landscapes and lead to conditions conducive for methane production. The methane is released to the atmosphere from the reservoir and as the water exits the turbines and from the downstream river. Balbina Reservoir near Manaus covers about 2400 km squared along the Uatuma River. Annual averages of measurements of methane emission from the various habitats in the reservoir range from 23 to 64 mg C per m squared per day. Total annual emission from the reservoir is about 58 Gg C. In addition, about 39 Gg C per year are released below the dam, about 50 percent of which is released as the water passes through the turbines. On an annual areal basis, Balbina Reservoir emits 40 Mg C km squared, in contrast to 30 Mg km squared for the Solimoes mainstem floodplain

  15. CHARACTERIZATION AND FORMATION MECHANISM OF THE CENTRAL UPLIFT OF THE QIANGTANG BASIN

    Institute of Scientific and Technical Information of China (English)

    YIN Fuguang

    2004-01-01

    The Qiangtang basin is located between Kekexili-Jingshajiang suture belt and Bangong-Lujiang suture belt, and is divided into the north part and south part by the central uplift that has no crop out of Mesozoic strata. When the Jinshajiang Ocean was closed, the subducting plate was subducted southward. In the central part of the Qiangtang basin, the cushioning effect of the asthenosphere resulted in the thermal doming of the mantle and subsequent large-scale anatexis. Mantle source materials and antectic materials were upwelled and extruded into the middle crust, leading to the thickening of the middle crust and the heating and weakening of the middle to upper crust, and resulting in the rapid deformation (detachment) and tectonic erosion, and in the isostatic uplifting and the formation of metamorphic core complex. The upwelling of anatectic materials would further enhance the buoyant repercussion, which would combine with the side stress due from extrusion in resulting in the formation of an extensional stress field. The extensional structure and detachment fault are formed under the influence of the losing stabilized gravitation. In the deformation area in both the upper part and the lower part, an extensional deposition area would be formed, and this is the generation of a new basin.The metamorphic core complex of the central uplift is comprised of gneiss, which is itself overlain by non-metamorphic to weakly metamorphic covering strata intersected by faults.

  16. Salar de Atacama basin: A record of compressional tectonics in the central Andes since the mid-Cretaceous

    Science.gov (United States)

    Arriagada, Cesar; Cobbold, Peter R.; Roperch, Pierrick

    2006-02-01

    The Salar de Atacama basin lies in the inner fore arc of northern Chile. Topographically and structurally, it is a first-order feature of the central Andes. The sedimentary fill of the basin constrains the timing and extent of crustal deformation since the mid-Cretaceous. We have studied good exposures along the western edge of the basin and have correlated them with seismic reflection sections and data from an exploration well. Throughout most of its history, the basin developed in a foreland setting, during periods of thin-skinned and thick-skinned thrusting. Growth strata provide evidence for coeval sedimentation and thrust motions during mid-Cretaceous, Paleogene, and Neogene times. Pre-Neogene deformation was significant in the basin and in surounding areas of the early central Andes. Models that attempt to explain the current thickness of the central Andes should consider Late Cretaceous and Paleogene shortening, as well as the more obvious Neogene and Quaternary shortening.

  17. Screening for antimicrobial activity among bacteria isolated from the Amazon Basin Atividade antimicrobiana entre bactérias isoladas da Bacia Amazônica

    Directory of Open Access Journals (Sweden)

    Amanda S. Motta

    2004-12-01

    Full Text Available Bacteria producing antimicrobial activity were identified among 86 isolates from aquatic environments of Brazilian Amazon Basin. Antimicrobial activity against at least one indicator strain was detected for 59 isolates (68.6%. Inhibitory activity was mostly against Gram-positive bacteria, such as Listeria monocytogenes and Bacillus cereus. The antimicrobial substances produced by 19 strains that showed higher inhibitory activity were partially characterized. These antimicrobial substances showed thermal resistance for up to 100°C and partial resistance to proteolytic treatment. Some antimicrobials were partially resistant to pronase E at 2 mg ml-1 or to treatment with trichloroacetic acid. Detection of antimicrobial activity on polyacrylamide gels revealed that the molecular weight of the compounds was lower than 14 kDa. Several strains showed antibacterial activity, which in some cases appear to be related to antimicrobial peptides. The potential of these microorganisms to produce useful antimicrobial compounds is great and must be better explored.Bactérias produtoras de atividade antimicrobiana foram identificadas entre 86 isolados de ambientes aquáticos da Bacia Amazônica. Destes, 59 isolados (68.6% apresentaram atividade antimicrobiana contra pelo menos uma bactéria indicadora. A atividade inibitória foi principalmente observada contra bactérias Gram-positivas, como Listeria monocytogenes e Bacillus cereus. As substâncias antimicrobianas produzidas por 19 linhagens que demonstraram maior atividade inibitória foram parcialmente caracterizadas, apresentando resistência térmica até 100°C e resistência parcial ao tratamento proteolítico. Algumas substâncias foram parcialmente inativadas somente quando tratadas com ácido tricloroacético ou com pronase E na concentração de 2 mg ml-1. A detecção da atividade antimicrobiana em géis de poliacrilamida mostrou que os compostos apresentaram peso molecular inferior à 14 kDa. V

  18. 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

    2004-02-01

    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. 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 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 ≤0.015 ppb for acidic trace gases and aerosol anions and ≤0.118 ppb 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

  19. 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

  20. An unusual, dwarf new species of Neotropical freshwater stingray, Plesiotrygon nana sp. nov., from the upper and mid Amazon basin: the second species of Plesiotrygon (Chondrichthyes: Potamotrygonidae

    Directory of Open Access Journals (Sweden)

    Marcelo R. de Carvalho

    2011-01-01

    Full Text Available A new species of the relatively poorly known Neotropical freshwater stingray genus Plesiotrygon Rosa, Castello & Thorson, 1987 is described from the main channel and smaller tributaries (Ríos Itaya and Pachitea of the upper Amazon basin in Peru. The first specimen to be collected, however, was from much farther east in Rio Solimões in 1996, just down-river from Rio Purus (specimen unavailable for this study. Plesiotrygon nana sp. nov., is a very distinctive and unusually small species of freshwater stingray (Potamotrygonidae, described here mostly from three specimens representing different size classes and stages of sexual maturity. Plesiotrygon nana sp. nov., is distinguished from its only congener, P. iwamae Rosa, Castello & Thorson, 1987, by numerous unique features, including: dorsal coloration composed of very fine rosettes or a combination of spots and irregular ocelli; very circular disc and snout; very small and less rhomboidal spiracles; short snout and anterior disc region; narrow mouth and nostrils; denticles on dorsal tail small, scattered, not forming row of enlarged spines; adult and preadult specimens with significantly fewer tooth rows; fewer caudal vertebrae; higher total pectoral radials; very small size, probably not surpassing 250 mm disc length or width, males maturing sexually at around 180 mm disc length and 175 mm disc width; distal coloration of tail posterior to caudal stings usually dark purplish-brown; and features of the ventral lateral-line canals (hyomandibular canal very narrow, infraorbital and supraorbital canals not undulated, supraorbital and infraorbital loops small and narrow, supraorbital loop very short, not extending posteriorly to level of mouth, jugular and posterior infraorbital canals short, not extending caudally to first gill slits, subpleural loop very narrow posteriorly; absence of anterior and posterior subpleural tubules. To provide a foundation for the description of P. nana sp. nov

  1. The U.S. Geological Survey`s National Coal Resource Assessment: The Northern and Central Appalachian Basin

    Energy Technology Data Exchange (ETDEWEB)

    Ruppert, L.; Bragg, L.; Tewalt, S. [Geological Survey, Reston, VA (United States)

    1996-09-01

    The US Geological Survey (USGS) Energy Resource Surveys Program is currently conducting a five-year National Coal Resource Assessment project. Primary focus is on the quality and quantity of top-producing coal beds and coal zones in five of the nine major coal producing regions in the US. These regions include the (1) Northern and Central Appalachian Basin, (2) Gulf Coastal Plain, (3) Illinois Basin, (4) Colorado Plateau, and (5) Powder River Basin and Northern Great Plains.

  2. Petrographic characterization and preliminary geochronologic data from volcanic rocks of the Iriri formation, southern-central portion of the Amazon Craton, Aripuana - Mato Grosso

    International Nuclear Information System (INIS)

    The Moriru area is located in the south-central portion of the Amazon Craton, near the border of Mato Grosso and Amazonas states. The research was carried out using eight drill cores, 200 meters deep in average. The description of these drill cores allowed the identification of felsic lavas and pyroclastics inter layered with mafic flows volcanoclastic and sedimentary rocks. Granitic intrusions are completely altered by hydrothermal metamorphism. Later stage dikes were identified. The pyroclastic successions is characterized by ignimbritic rocks generated by pumice flows. The ignimbrites are enriched in pumice and phenocrysts and are classified as crystal enriched ignimbrite. The content of fine particles is low and the welding grade ranges from good to medium. The composition of ignimbrites is rhyodacite to dacite. U-Pb zircon ages are 1801+- 11 Ma for ignimbrites and 1848+-9 Ma for mafic volcanics. However, for the mafic rocks age may represent some inherited zircon. More data from these rocks are necessary before we can make a definitive conclusion. The air fall deposits are represented by ash tuff enriched in vitroclasts. The volcanogenic sedimentary deposits occur inter layered with pyroclastic deposits and are represented by volcanoclastic conglomerates and immature tuffaceous sandstones. The volcanic particles in this sequence, partially maintain igneous characteristics, which suggests small amount of reworking and a possible proximity to the source. Sulfides occur disseminated in sub-volcanic and in late-stage quartz-carbonate-chlorite veins. (author)

  3. DISTRIBUTION, ABUNDANCE AND ENTRAINMENT STUDIES OF LARVAL FISHES IN THE WESTERN AND CENTRAL BASINS OF LAKE ERIE

    Science.gov (United States)

    To assess the impact of entrainment of larval fishes at steam generating electrical power plants, samples were collected in Lake Erie. In 1975, 1976 and 1977 the Western Basin was sampled and in 1978 the sampling was concentrated in the Central Basin. The 1975, 1976 sampling perm...

  4. Fate of copper complexes in hydrothermally altered deep-sea sediments from the Central Indian Ocean Basin.

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, P.; Sander, S.G.; Jayachandran, S.; Nath, B.N.; Nagaraju, G.; Chennuri, K.; Vudamala, K.; Lathika, N.; Mascarenhas-Pereira, M.B.L.

    -EDTA complexes. The speciation of Cu indicates that hydrothermally influenced deep-sea sediments from Central Indian Ocean Basin may not significantly contribute to the global Cu flux. However, increasing lability of Cu-sediment complexes with increasing depth...

  5. Assessing the distribution and abundance of seabed minerals from seafloor photographic data in the Central Indian Ocean Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, R.; Khadge, N.H.; JaiSankar, S.

    estimation of a deposit from photographic data in conjunction with sounding and sampling data in the Central Indian Ocean Basin. Data from more than 20,000 photos were analysed and correlated with geological features such as bathymetry, sediment thickness...

  6. Thermohaline circulation in the Central Indian Ocean Basin (CIB) during austral summer and winter periods of 1997

    Digital Repository Service at National Institute of Oceanography (India)

    RameshBabu, V.; Suryanarayana, A.; Murty, V.S.N.

    As a part of Indian Deep Sea Environment Experiment (INDEX) aimed at assessing the environmental impact of manganese nodule mining in the Central Indian Basin (CIB), a study on baseline physical conditions of water column viz. potential temperature...

  7. Bacterial standing stock, meiofauna and sediment-nutrient characteristics: Indicators of benthic disturbance in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, C.; LokaBharathi, P.A.; Ansari, Z.A.; Nair, S.; Ingole, B.S.; Sheelu, G.; Mohandass, C.; Nath, B.N.; Rodrigues, N.

    As a part of the environmental impact assessment studies for polymetallic nodule mining, the effect of simulated "benthic disturbance" caused by a benthic hydraulic disturber was studied in the Central Indian Basin (CIB). The abundance...

  8. Nature and distribution of manganese nodules from three sediment domains of the Central Indian Basin, Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.; Mukhopadhyay, R.

    Manganese nodules from the Central Indian Basin (5 degrees-10 degrees S) vary in abundance, morphology, mineralogy, and chemistry with water depth and sediment type. Nodules from the southern region, dominatEd. by siliceous sediment, differ markedly...

  9. Hydrologic response of a high altitude glacierized basin in the central Tibetan Plateau

    Science.gov (United States)

    Li, Binquan; Yu, Zhongbo; Liang, Zhongmin; Acharya, Kumud

    2014-07-01

    Hydrologic cycles of most high altitude glacierized watersheds in the Tibetan Plateau are not closely monitored due to their inaccessibility. Understanding the hydrologic cycle in such a basin may provide insight into the role climate plays on changes in glacier mass. Thus, hydrologic simulations with a physical perspective in the Tibetan glacierized watershed are of great significance. A high altitude glacierized basin in the central Tibetan Plateau, Qugaqie basin, was investigated with an energy-balance based glacier-melt model and the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model. With these two models, glacier mass balance was estimated and basin runoff from glaciers was simulated at a daily time step. Results from the simulation period (October 1, 2006-September 30, 2011) demonstrated that the glaciers experienced a large negative surface mass balance with the cumulative value of - 300 cm w.e.. In other words, up to 13.93 × 106 m3 water volume was melting out from the glaciers during these five years. In the 2007/08 year, however, the glaciers experienced a surplus mass balance because of the low air temperature and increased precipitation in the summer season. Infiltration, evapotranspiration (ET), and overland flow were also calculated using the GSSHA model. Results showed that precipitation, the main water source, contributed roughly 95% to the total mass gain of the annual water balance in the Qugaqie basin during the study period, while the glacial runoff (snow/ice melting) contributed 5% water balance. In the water loss, 17% of annual water volume was consumed by the ET process. As a result, the remaining water volume (83%) converted to the basin river flow to the Lake Nam Co. In the summertime, the glacial runoff accounted for 15% of the total basin runoff volume, while this contribution increased in the upstream portion to 46% due to a large percentage of glacierized area. The analysis showed that the glacial runoff contributions to the

  10. The Amazon River reversal explained by tectonic and surface processes

    Science.gov (United States)

    Sacek, V.

    2014-12-01

    The drainage pattern in Amazonia was expressively modified during the mountain building of central and northern Andes. In Early Miocene, the fluvial systems in western Amazonia flowed to the foreland basins and northward to the Caribbean. By Late Miocene the drainage reversal occurred and formed the transcontinental Amazon River, connecting the Andes and the equatorial Atlantic margin. This event is recorded in the stratigraphic evolution of the Foz do Amazonas Basin by the onset of Andean-derived sedimentation. Additionally, an abrupt increase in sedimentation rate after the reversal occurred in the Foz do Amazonas Basin. Based on three-dimensional numerical models that couple surface processes, flexural isostasy and crustal thickening due to orogeny, I concluded that the Miocene drainage reversal can be explained by the flexural and surface processes response to the Andes formation with no need to invoke dynamic topography induced by mantle convection, as previously proposed. I observed that the instant of drainage reversal is directly linked to the rate of crustal thickening in the orogeny, the rate of erosion and, mainly, the efficiency of sediment transport. Moreover, the numerical experiments were able to predict the increase in sedimentation rate in the Amazon fan after the drainage reversal of the Amazon River as observed in the Late Miocene-Pliocene sedimentary record. However, the present numerical model fails to fully reproduce the evolution of the Pebas system, a megawetland in western Amazonia that preceded the drainage reversal. Therefore, further investigation is necessary to evaluate the mechanisms that generated and sustained the Pebas system.

  11. Agroforestry systems in the Amazon

    OpenAIRE

    Křížek, Stanislav

    2013-01-01

    Intensity and change of agricultural utilization of the Amazon basin is one of main problems of colonization in the area. Specific soil and climate conditions require suitable land use patterns, which were evolved through the centuries by indigenous population, are examined by many individuals and scientific institutions. Agroforestry systems (AFS) involve many of these practices. Soil protection, carbon sequestration, food security and high biodiversity are main benefits of AFS, which are ch...

  12. Climate Change Impacts on Runoff Regimes at a River Basin Scale in Central Vietnam

    Directory of Open Access Journals (Sweden)

    Do Hoai Nam

    2012-01-01

    Full Text Available Global warming has resulted in significant variability of global climate especially with regard to variation in temperature and precipitation. As a result, it is expected that river flow regimes will be accordingly varied. This study presents a preliminary projection of medium-term and long-term runoff variation caused by climate change at a river basin scale. The large scale precipitation projection at the middle and the end of the 21st century under the A1B scenario simulated by the CGCM model (MRI & JMA, 300 km resolution is statistically downscaled to a basin scale and then used as input for the super-tank model for runoff analysis at the upper Thu Bon River basin in Central Vietnam. Results show that by the middle and the end of this century annual rainfall will increase slightly; together with a rising temperature, potential evapotranspiration is also projected to increase as well. The total annual runoff, as a result, is found to be not distinctly varied relative to the baseline period 1981 - 2000; however, the runoff will decrease in the dry season and increase in the rainy season. The results also indicate the delay tendency of the high river flow period, shifting from Sep-Dec at present to Oct-Jan in the future. The present study demonstrates potential impacts of climate change on streamflow regimes in attempts to propose appropriate adaptation measures and responses at the river basin scales.

  13. Determination of hydrocarbon prospective areas in the Tuzgolu (Saltlake) Basin, central Anatolia, by using geophysical data

    Energy Technology Data Exchange (ETDEWEB)

    Aydemir, Attila [Turkiye Petrolleri A.O. Mustafa Kemal Mah. 2.Cad. No: 86, 06100 Sogutozu, Ankara (Turkey); Ates, Abdullah [Ankara University, Faculty of Engineering, Department of Geophysical Engineering, 06100, Besevler, Ankara (Turkey)

    2008-09-15

    Tuzgolu Basin is the largest interior basin in Central Anatolia, Turkey, with significant hydrocarbon indications in outcrops and exploration wells. However, there is no commercial discovery since 1959 which is the beginning year of exploration activities. Because of the poor seismic quality, all available geological-geophysical data and methods should be used in integration with each other to carry out exploration activities. In previous studies, the basin was modeled three dimensionally (3D) using gravity data by the authors of this paper and results of the modeling study were published recently. The model results can be evaluated to determine probable hydrocarbon generation zones. Gravity anomalies in this region exhibit many inflections that could be prospective locations for hydrocarbons. In this study, the gravity data were subjected to the vertical derivative in order to isolate inflections and to determine concealed structurally high areas in the subsurface that could have hydrocarbon potential. These potential subsurface structures were also compared with the Analytical Signal map produced from the aeromagnetic anomalies to reveal if they are originated from a magmatic intrusion. Finally, it was determined that all exploration wells were drilled off-structure and none of these potential subsurface structures was tested. According to correlation of the previous well locations and determined subsurface structures in or around the hydrocarbon generation zones, it is possible to claim that the Tuzgolu Basin with no previous discovery remains prospective for hydrocarbon exploration activities in the future. (author)

  14. Stratigraphy, sedimentology and paleontology of lower Eocene San Jose formation, central San Juan basin, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, S.G.; Smith, L.N. (New Mexico Museum of Natural History, Albuquerque (USA))

    1989-09-01

    The lower Eocene San Jose Formation in the central portion of the San Juan basin (Gobernador-Vigas Canyon area) consists of the Cuba Mesa, Regina, Llaves, and Tapicitos Members. Well log data indicate that, from its 100-m thickness, the Cuba Mesa Member thins toward the basin center and pinches out to the northeast by lat. 36{degree}40'N, long. 107{degree}19'W. The Regina Member has the most extensive outcrops in the central basin, and it decreases in sandstone/mud rock ratio to the north. The Llaves and Tapicitos Members occur only at the highest elevations, are thin due to erosion, and are not mappable as separate units. Well log data and 1,275 m of measured stratigraphic section in the Regina, Llaves, and Tapicitos Members indicate these strata are composed of approximately 35% medium to coarse-grained sandstone and 65% fine-grained sandstone and mud rock. Sedimentology and sediment-dispersal patterns indicate deposition by generally south-flowing streams that had sources to the northwest, northeast, and east. Low-sinuosity, sand-bedded, braided( ) streams shifted laterally across about 1 km-wide channel belts to produce sheet sandstones that are prominent throughout the San Jose Formation. Subtle levees separated channel environments from floodplain and local lacustrine areas. Avulsion relocated channels periodically to areas on the floodplain, resulting in the typically disconnected sheet sandstones within muddy overbank deposits of the Regina Member.

  15. Holocene mammalian change in the central Columbia Basin of eastern Washington state, USA

    Science.gov (United States)

    Lyman, R. Lee

    2016-08-01

    Predictions of changes in the Holocene mammalian fauna of the central Columbia Basin in eastern Washington (USA) based on environmental changes are largely met. Taxonomic richness is greatest during periods of cool-moist climate. Rates of input of faunal remains to the paleozoological record may suggest greater mammalian biomass during periods of greater moisture but are difficult to interpret without data on sampling intensity in the form of volume of sediment excavated. Abundances of leporids and grazing ungulates fluctuate in concert with abundance of grass. Several biogeographic records are tantalizing but require additional study and data before being accepted as valid. Records of red fox (Vulpes vulpes) indicate this species was present in the central basin during the Holocene contrary to historic records and recent suggestions modern foxes there are escapees from fur farms. Bison (Bison bison) and bighorn sheep (Ovis canadensis) underwent diminution of body size during the Holocene. Modern efforts to conserve the Columbia Basin ecosystem are advised to consider the Holocene record as indicative of what may happen to that ecosystem in the future.

  16. Glacier characteristics and changes in the Sary-Jaz River Basin (Central Tien Shan, Kyrgyzstan) – 1990–2010

    OpenAIRE

    Osmonov, Azamat; Bolch, Tobias; Xi, Chen; Kurban, Alishir; Guo, Wanqing

    2013-01-01

    The water discharge from the heavily glacierized Sary-Jaz River Basin (Eastern Kyrgyzstan) is of high importance for the very arid Tarim Basin located in Xinjiang (north-western China). We investigated glacier changes in the entire Sary-Jaz River Basin, which covers a large part of the Central Tien Shan, for the period from 1990 to 2010 based on Landsat ‘TM’/‘ETM+’data. We found 1310 glaciers (>0.1 km²), which covered 2055 ± 41.1 km² (∼18% of the entire basin) in 1990. The glaciers shrank by ...

  17. Federally owned coal and Federal lands in the northern and central Appalachian Basin coal regions

    Energy Technology Data Exchange (ETDEWEB)

    Susan J. Tewalt

    2002-02-01

    The US Geological Survey (USGS) assessed five coals beds or coal zones in the northern and central Appalachian Basin coal regions for the National Coal Resource Assessment: the Pittsburgh coal bed, the Upper Freeport coal bed, the Fire Clay coal zone, the Pond Creek coal zone, and the Pocahontas No. 3 coal bed. The assessment produced stratigraphic and geochemical databases and digital coal maps, or models, which characterized the coal beds and coal zones. Using the assessment models, the USGS estimated original and remaining (unmined) resources for these coal beds or zones. The Appalachian Basin assessment was conducted in collaboration with the State geological surveys of West Virginia, Pennsylvania, Ohio, Maryland, Kentucky, and Virginia. 3 refs., 7 figs.

  18. Coal resources of selected coal beds and zones in the northern and central Appalachian Basin

    Energy Technology Data Exchange (ETDEWEB)

    Leslie Ruppert; Susan Tewalt; Linda Bragg

    2002-02-01

    The U.S. Geological Survey (USGS) is completing a National Coal Resource Assessment of five coal-producing regions of the United States, including the Appalachian Basin. The USGS, in cooperation with the State geological surveys of Kentucky, Maryland, Ohio, Pennsylvania, Virginia, and West Virginia, has completed a digital coal resource assessment of five of the top-producing coal beds and coal zones in the northern and central Appalachian Basin coal regions -- the Pittsburgh coal bed, the Upper Freeport coal bed, the Fire Clay and Pond Creek coal zones, and the Pocahontas No. 3 coal bed. Of the 93 billion short tons of original coal in these units, about 66 billion short tons remain. 2 refs., 5 figs., 2 tabs.

  19. Preliminary description of hydrologic characteristics and contaminant transport potential of rocks in the Pasco Basin, south-central Washington

    International Nuclear Information System (INIS)

    This report aims at consolidating existing data useful in defining the hydrologic characteristics of the Pasco Basin within south-central Washington. It also aims at compiling the properties required to evaluate contaminant transport potential within individual subsurface strata in this basin. The Pasco Basin itself is a tract of semi-arid land covering about 2,000 square miles in south-central Washington. The regional geology of this basin is dominated by tholeiitic flood basalts of the Columbia Plateau. The surface hydrology of the basin is dominated by the Yakima, Snake, and Columbia rivers. Short-lived ephemeral streams may flow for a short period of time after a heavy rainfall or snowmelt. The subsurface hydrology of the Pasco Basin is characterized by an unconfined aquifer carrying the bulk of the water discharged within the basin. This aquifer overlies a series of confined aquifers carrying progressively smaller amounts of groundwater as a function of depth. The hydraulic properties of the various aquifers and non-water-bearing strata are characterized and reported. A summary of the basic properties is tabulated. The hydrochemical data obtained are summarized. The contaminant transport properties of the rocks in the Pasco Basin are analyzed with emphasis on the dispersion and sorption coefficients and the characteristics of the potential reactions between emplaced waste and the surrounding medium. Some basic modeling considerations of the hydrogeologic systems in the basin with a brief discussion of model input requirements and their relationship to available data are presented

  20. Paleoseismological investigations and Geomorphology on the Gaenserndorf Terrace in the central Vienna Basin (Austria)

    Science.gov (United States)

    Weissl, Michael; Hintersberger, Esther; Lomax, Johanna; Decker, Kurt

    2016-04-01

    In the central Vienna Basin normal faults define the eastern and western margins of Pleistocene Danube terraces north of Vienna. The terrace body is built up of coarse sandy gravel and sand. Locally the terrace surface is covered with eolian and alluvial sediments of the last glacial revealing OSL/IRSL ages of about 15-16 ka. High resolution digital terrain models (LIDAR) show relicts of a periglacial landscape in the northern part of the Middle Pleistocene (MIS 8) terrace. Large elongated depressions in the northern parts of the terrace are interpreted as the basins of former thermokarst lakes due to analogies in recent periglacial zones. Draining valleys corrugate the fault scarps indicating advanced subsidence of the Aderklaa and Obersiebenbrunn Quaternary basins before the last Glacial. Obviously the periglacial morphology is only preserved in the elevated parts of the terrace which is located in the footwall of the bounding normal faults. In the hanging wall Quaternary basins are filled with up to 40 m thick Pleistocene and Holocene growth strata. During the last decade three faults were investigated by trenching. In contrast to the earlier trench sites on the Markgrafneusiedl Fault and the Vienna Basin Transform Fault it was not possible to provide clear evidence for offset on the Aderklaa-Bockfliess fault because cryoturbation deformed the covering fluvial sediments together with the underlying Gaenserndorf terrace gravels. However it was possible to localize this fault precisely applying an electrical resistivity tomography. The resulting ERT-section shows an offset of the 200-300 ky old terrace and the underlying Miocene sediments of about 9-10 meters suggesting a vertical slip rate of 0.03 - 0.05 mm/a.

  1. A review of green- and blue-water resources and their trade-offs for future agricultural production in the Amazon Basin: what could irrigated agriculture mean for Amazonia?

    Science.gov (United States)

    Lathuillière, Michael J.; Coe, Michael T.; Johnson, Mark S.

    2016-06-01

    The Amazon Basin is a region of global importance for the carbon and hydrological cycles, a biodiversity hotspot, and a potential centre for future economic development. The region is also a major source of water vapour recycled into continental precipitation through evapotranspiration processes. This review applies an ecohydrological approach to Amazonia's water cycle by looking at contributions of water resources in the context of future agricultural production. At present, agriculture in the region is primarily rain-fed and relies almost exclusively on green-water resources (soil moisture regenerated by precipitation). Future agricultural development, however, will likely follow pathways that include irrigation from blue-water sources (surface water and groundwater) as insurance from variability in precipitation. In this review, we first provide an updated summary of the green-blue ecohydrological framework before describing past trends in Amazonia's water resources within the context of land use and land cover change. We then describe green- and blue-water trade-offs in light of future agricultural production and potential irrigation to assess costs and benefits to terrestrial ecosystems, particularly land and biodiversity protection, and regional precipitation recycling. Management of green water is needed, particularly at the agricultural frontier located in the headwaters of major tributaries to the Amazon River, and home to key downstream blue-water users and ecosystem services, including domestic and industrial users, as well as aquatic ecosystems.

  2. Barbados Corals as Recorders of Amazon River Salinity Anomalies

    Science.gov (United States)

    Greer, L.; Telfeyan, K.; Arienzo, M. M.; Rosenberg, A. D.; Waite, A. J.; Swart, P. K.

    2010-12-01

    Low salinity plumes of Amazon and Orinoco sourced water have previously been detected around the island of Barbados. Barbados corals may therefore have the potential to record salinity anomalies governed by natural, climate-related, and anthropogenic changes in the Amazon and Orinoco Basin watersheds beyond the recent historic record. In order to determine whether Barbados corals record salinity variations associated with local or Amazon/Orinoco sourced signals, multiple specimens of Montastraea sp. and Siderastrea sp. coral skeletons were analyzed for stable C and O isotope and Sr/Ca variations. Corals were collected from the northwest, central-west, and southwest regions of the island to determine degree of salinity signal heterogeneity over a 5-6 year period at approximately monthly resolution. Four separate published paleotemperature equations were used to assess the importance of temperature on stable oxygen isotope composition. In situ temperature measurements obtained from NOAA show an annual sea surface temperature (SST) cycle of approximately 4 degrees Celsius off Barbados. If governed solely by SST, stable isotope data from all 8 corals in this study indicate a significantly greater annual temperature range of approximately 6 degrees Celsius. This suggests that salinity related fluctuations in oxygen isotopic composition of water are an important influence on the geochemistry of Barbados corals. Some regional differences in geochemical composition of corals were apparent. Corals from the southwest of Barbados showed the clearest sub-annual isotope signal, better correlations with mean annual SST measurements, and lowest mean salinity of the regions. Corals from the central-west and northwest showed distinctly higher mean, but more variable, salinity than corals from the south. Stable carbon isotope data from southwest corals also best potentially reflect the Suess Effect. Montastraea sp. corals generally show a higher paleotemperature offset from in situ

  3. Extensional fault-bend folding and synrift deposition: An example from the Central Sumatra basin, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, J.H.; Hook, S.C. [Texaco Exploration and Production Technology Dept., Houston, TX (United States); Sitohang, E.P. [PT CALTEX Pacific Indonesia, Pekanbaru (Indonesia)

    1997-03-01

    We describe an analytical method for interpreting the geometry and structural history of asymmetric half grabens in rift basins with extensional fault-bend fold theory. Using seismic reflection profiles from the Central Sumatra basin and balanced forward models, we show how local variations in tectonic subsidence relative to deposition rates yield distinctive patterns of folded synrift strata and unconformities that record basin history. If the deposition rate exceeds the local subsidence rate, folded growth strata form upwardly narrowing kink bands that have been described previously as growth triangles. In contrast, if the deposition rate is less than or equals the local subsidence rate, growth strata are folded and truncated at the surface on half-graben margins. Subsequent increases in deposition rate relative to subsidence rate form angular unconformities near the half-graben margins. These unconformities develop without the necessity of erosion and are folded by continuing fault slip. Strata above and below the unconformities are concordant in the deeper parts of the half grabens. Thus, angular unconformities on half-graben margins are helpful for defining sequence boundaries that may reflect changes in deposition and tectonic subsidence rates. In addition, fault-bend fold interpretations yield fault geometry and measures of horizontal extension, both of which control three-dimensional half-graben geometry and accommodation space. We show how along-strike variations in fault geometry produce intrabasinal structures that may form prospective fair-ways or local depocenters.

  4. Sedimentology and diagenesis of a rift basin lacustrine sandstone: Pematang group, central Sumatra, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Janks, J.S.; Kelley, P.A.; Williams, H.H.

    1986-05-01

    The Central Sumatra basin is a back-arc basin that formed during the Paleocene as a series of half-graben structures. These early formed half-graben structures were filled with nonmarine clastics and lacustrine sediments of the Pematang Group, sourced from local highland areas. The Pematang Group consists of the Lower Red Beds, Brown Shale, Coal Zone Member, and Lake Fill Formation (in ascending order). The Pematang Group sedimentology is intimately related to the regional and basinal tectonic development and history. Sandstones of the Pematang Group are predominantly sublitharenites and litharenites; feldspars are rare. Sandstone diagenesis is relatively uniform regardless of the depositional environment. Diagenetic modifications include compaction, early calcite and dolomite cementation, quartz overgrowth formation, unstable rock-fragment dissolution, kaolinite precipitation, siderite formation, and local illite formation. Secondary porosity accounts for up to 50% of the effective porosity and was created by rock-fragment dissolution. This dissolution is probably caused by the organic acids released during kerogen maturation. Stable isotope data from diagenetic siderite are presented.

  5. Seven new species of Lachesilla (Psocodea: 'Psocoptera': Lachesillidae, in the group forcepeta from the Amazon Basin Sete espécies novas de Lachesilla Westwood (Psocodea:'Psocoptera': Lachesillidae do grupo forcepeta da Bacia Amazônica

    Directory of Open Access Journals (Sweden)

    Alfonso N. García Aldrete

    2010-12-01

    Full Text Available Seven new species of Lachesilla in the group forcepeta, from the Amazon Basin in Brazil, Colombia and Peru, are here described and illustrated: L. amacayacuensis sp. n. (type locality: Colombia, Amazonas, Leticia, Amacayacú; L.bulbosiforceps sp. n. (type locality: Peru, Cuzco; L. cuzcoensis sp. n. (type locality: Peru, Cuzco; L. marabaensis sp. n. (type locality: Brasil, Pará, Marabá, Serra Norte; L. pilosiforceps sp. n. (type locality: Brasil, Pará, Oriximiná, Rio Trombetas; L. pilosipenna sp. n. (type locality: Peru, Cuzco; L. squamiforceps sp. n. (type locality: Colombia, Amazonas, Leticia. The Amazon Basin is the second most rich world area for species of Lachesilla.São descritas e ilustradas sete espécies de Lachesilla do grupo forcepeta, provenientes da bacia amazônica do Brasil, Colômbia e Peru: L. amacayacuensis sp. n. (localidade-tipo: Colômbia, Amazonas, Leticia, Amacayacú; L. bulbosiforceps sp. n. (localidade-tipo: Peru, Cuzco; L. cuzcoensis sp. n. (localidade-tipo: Peru, Cuzco; L. marabaensis sp. n. (localidade-tipo: Brasil, Pará, Marabá, Serra Norte; L. pilosiforceps sp. n. (localidade-tipo: Brasil, Pará, Oriximiná, Rio Trombetas; L. pilosipenna sp. n. (localidade-tipo: Peru, Cuzco; L. squamiforceps sp. n. (localidade-tipo: Colômbia, Amazonas, Letícia. A região amazônica é a segunda mais rica em número de espécies de Lachesilla.

  6. Ethiopian Central Rift Valley basin hydrologic modelling using HEC-HMS and ArcSWAT

    Science.gov (United States)

    Pascual-Ferrer, Jordi; Candela, Lucila; Pérez-Foguet, Agustí

    2013-04-01

    An Integrated Water Resources Management (IWRM) shall be applied to achieve a sustainable development, to increase population incomes without affecting lives of those who are highly dependent on the environment. First step should be to understand water dynamics at basin level, starting by modeling the basin water resources. For model implementation, a large number of data and parameters are required, but those are not always available, especially in some developing countries where different sources may have different data, there is lack of information on data collection, etc. The Ethiopian Central Rift Valley (CRV) is an endorheic basin covering an area of approximately 10,000 km2. For the period 1996-2005, the average annual volume of rainfall accounted for 9.1 Mm3, and evapotranspiration for 8 Mm3 (Jansen et al., 2007). From the environmental point of view, basin ecosystems are endangered due to human activities. Also, poverty is widespread all over the basin, with population mainly living from agriculture on a subsistence economy. Hence, there is an urgent need to set an IWRM, but datasets required for water dynamics simulation are not too reliable. In order to reduce uncertainty of numerical simulation, two semi-distributed open software hydrologic models were implemented: HEC-HMS and ArcSWAT. HEC-HMS was developed by the United States Army Corps of Engineers (USACoE) Hydrologic Engineering Center (HEC) to run precipitation-runoff simulations for a variety of applications in dendritic watershed systems. ArcSWAT includes the SWAT (Soil and Water Assessment Tool, Arnold et al., 1998) model developed for the USDA Agricultural Research Service into ArcGIS (ESRI®). SWAT was developed to assess the impact of land management practices on large complex watersheds with varying soils, land use and management conditions over long periods of time (Neitsch et al., 2005). According to this, ArcSWAT would be the best option for IWRM implementation in the basin. However

  7. 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).

  8. Estimates of ground-water recharge rates for two small basins in central Nevada

    International Nuclear Information System (INIS)

    Estimates of ground-water recharge rates developed from hydrologic modeling studies are presented for 3-Springs and East Stewart basins, two small basins (analog sites) located in central Nevada. The analog-site studies were conducted to aid in the estimation of recharge to the paleohydrologic regime associated with ground water in the vicinity of Yucca Mountain under wetter climatic conditions. The two analog sites are located to the north and at higher elevations than Yucca Mountain, and the prevailing (current) climatic conditions at these sites is thought to be representative of the possible range of paleoclimatic conditions in the general area of Yucca Mountain during the Quaternary. Two independent modeling approaches were conducted at each of the analog sites using observed hydrologic data on precipitation, temperature, solar radiation, stream discharge, and chloride-ion water chemistry for a 6-year study period (October 1986 through September 1992). Both models quantify the hydrologic water-balance equation and yield estimates of ground-water recharge, given appropriate input data. Results of the modeling approaches support the conclusion that reasonable estimates of average-annual recharge to ground water range from about 1 to 3 centimeters per year for 3-Springs basin (the drier site), and from about 30 to 32 centimeters per year for East Stewart basin (the wetter site). The most reliable results are those derived from a reduced form of the chloride-ion model because they reflect integrated, basinwide processes in terms of only three measured variables: precipitation amount, precipitation chemistry, and streamflow chemistry

  9. Minibasins and salt canopy in foreland fold-and-thrust belts: The central Sivas Basin, Turkey

    Science.gov (United States)

    Kergaravat, Charlie; Ribes, Charlotte; Legeay, Etienne; Callot, Jean-Paul; Kavak, Kaan Sevki; Ringenbach, Jean-Claude

    2016-06-01

    The Sivas Basin in the Central Anatolian Plateau (Turkey), which formed in the context of a foreland fold-and-thrust belt (FTB), exhibits a typical wall and basin (WAB) province characterized by symmetric minibasins separated by continuous steep-flanked walls and diapirs. Extensive fieldwork including regional and detailed local mapping of the contacts and margins of minibasins, and interpretation of a set of 2-D regional seismic lines, provide evidence for the development of a shallow evaporite level separating two generations of minibasins within the WAB province. Here beds of symmetric exposed minibasins along diapir flank are younger than minibasins observed over autochthonous evaporites. Laterally away from the WAB province, increase in wavelength of the tectonic structures suggests a deepening of the decollement level. We interpret that a shallower evaporite level developed in the form of an evaporite canopy, triggered by significant lateral shortening. The Upper Eocene-Lower Oligocene autochthonous Tuzhisar evaporite level was remobilized by the northward migrating sedimentary load and the tilting of the southern basin margin during propagation of the foreland fold-and-thrust belt. Asymmetric and symmetric primary minibasins were overrun by an allochthonous sheet forming a canopy. A second generation of salt withdrawal minibasins subsided into the allochthonous salt sheet. The polygonal pattern of the WAB province influences the growing fold-and-thrust belt system during the late stage of the secondary minibasins development. The Sivas FTB basin is the result of the interaction between fold-and-thrust belt propagation, evaporite remobilization, and interaction between evaporite flow and sedimentation in the minibasins.

  10. Polyphase tectonic subsidence evolution of the Vienna Basin inferred from quantitative subsidence analysis of the northern and central parts

    Science.gov (United States)

    Lee, Eun Young; Wagreich, Michael

    2016-04-01

    The Vienna Basin is a tectonically complex Neogene basin situated at the Alpine-Carpathian transition. This study analyzes a detailed quantification of subsidence in the northern and central parts of the Vienna Basin to understand its tectonic subsidence evolution. About 200 wells were used to arrange stratigraphic setting, and wells reaching the pre-Neogene basement were analyzed for subsidence. To enhance the understanding of the regional subsidences, the wells were sorted into ten groups based on their position on major fault blocks. In the Early Miocene, subsidence was slow and along E-W to NE-SW trending axis, indicating the development of thrust-controlled piggyback basins. During the late Early Miocene data show abruptly increasing subsidence, making the initiation of the Vienna pull-apart basin system. From the Middle Miocene, the tectonic subsidence curves show regionally different patterns. The tectonic subsidence during the Middle Miocene varies laterally across the Vienna Basin, and the differential subsidence can be related to the changing tensional regime of weakening transtension and strengthening extension toward the late Middle Miocene. From the late Middle Miocene to the Late Miocene, the tectonic subsidence occurred dominantly along the regional active faults, and corresponds to the axis of E-W trending extension of the western parts of the Pannonian Basin system. In the Quaternary the Vienna Basin has been reactivated, and resulted in subsidence along the NE-SW trending Vienna Basin transfer fault system.

  11. Estimation of evapotranspiration in the Rainbow Springs and Silver Springs basins in North-Central Florida

    Science.gov (United States)

    Knowles, Leel, Jr.

    1996-01-01

    Estimates of evapotranspiration (ET) for the Rainbow and Silver Springs ground-water basins in north-central Florida were determined using a regional water-~budget approach and compared to estimates computed using a modified Priestley-Taylor (PT) model calibrated with eddy-correlation data. Eddy-correlation measurements of latent 0~E) and sensible (H) heat flux were made monthly for a few days at a time, and the PT model was used to estimate 3,E between times of measurement during the 1994 water year. A water-budget analysis for the two-basin area indicated that over a 30-year period (196594) annual rainfall was 51.7 inches. Of the annual rainfall, ET accounted for about 37.9 inches; springflow accounted for 13.1 inches; and the remaining 0.7 inch was accounted for by stream-flow, by ground-water withdrawals from the Floridan aquifer system, and by net change in storage. For the same 30-year period, the annual estimate of ET for the Silver Springs basin was 37.6 inches and was 38.5 inches for the Rainbow Springs basin. Wet- and dry-season estimates of ET for each basin averaged between nearly 19 inches and 20 inches, indicating that like rainfall, ET rates during the 4-month wet season were about twice the ET rates during the 8-month dry season. Wet-season estimates of ET for the Rainbow Springs and Silver Springs basins decreased 2.7 inches, and 3.4 inches, respectively, over the 30-year period; whereas, dry-season estimates for the basins decreased about 0.4 inch and1.0 inch, respectively, over the 30-year period. This decrease probably is related to the general decrease in annual rainfall and reduction in net radiation over the basins during the 30-year period. ET rates computed using the modified PT model were compared to rates computed from the water budget for the 1994 water year. Annual ET, computed using the PT model, was 32.0 inches, nearly equal to the ET water-budget estimate of 31.7 inches computed for the Rainbow Springs and Silver Springs basins

  12. Structural control of the basement in the central portion of the Santos Basin-Brazil; Controle estrutural do embasamento na porcao central da Bacia de Santos

    Energy Technology Data Exchange (ETDEWEB)

    Izeli, Maira G.B.; Morales, Norberto; Souza, Iata A. de [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas

    2008-07-01

    New discoveries of oil in deep water and ultra-deep water in Santos Basin suggest that it needs to be studied to better understanding of basement structures and their role in the basin control and configuration. This study characterizes the main tectonic structures of a portion at the central area of this basin, looking for their relation to the geological basement framework. The study is based on the integration of the geological and geophysical data from subsurface (offshore) and surface of the adjacent continent. These analyses include the continental structures that continue in direction of this basin (Guapiara Lineament and Ponta Grossa Arc), checking their possible influence on the basin evolution and deformation. To achieve the proposed goals, the Precambrian basement lineaments were extracted from the offshore area using remote sensing, as result was obtained strong NW-SE structural trend. According to the interpretation of seismic sections, it is possible to observe that this portion of the basin presents main NE-SW structural trend, and most of the structures are typical of passive margin and halokintics process. It is possible to see that some recognized faults in the rift deposits may be coinciding with the main continental guidelines which are projected into the basin. (author)

  13. Surface uplift and convective rainfall along the southern Central Andes (Angastaco Basin, NW Argentina)

    Science.gov (United States)

    Pingel, Heiko; Mulch, Andreas; Alonso, Ricardo N.; Cottle, John; Hynek, Scott A.; Poletti, Jacob; Rohrmann, Alexander; Schmitt, Axel K.; Stockli, Daniel F.; Strecker, Manfred R.

    2016-04-01

    Stable-isotopic and sedimentary records from the orogenic Puna Plateau of NW Argentina and adjacent intermontane basins to the east furnish a unique late Cenozoic record of range uplift and ensuing paleoenvironmental change in the south-central Andes. Today, focused precipitation in this region occurs along the eastern, windward flanks of the Eastern Cordillera and Sierras Pampeanas ranges, while the orogen interior constitutes high-elevation regions with increasingly arid conditions in a westward direction. As in many mountain belts, such hydrologic and topographic gradients are commonly mirrored by a systematic relationship between the oxygen and hydrogen stable isotope ratios of meteoric water and elevation. The glass fraction of isotopically datable volcanic ash intercalated in sedimentary sequences constitutes an environmental proxy that retains a signal of the hydrogen-isotopic composition of ancient precipitation. This isotopic composition thus helps to elucidate the combined climatic and tectonic processes associated with topographic growth, which ultimately controls the spatial patterns of precipitation in mountain belts. However, between 25.5 and 27°S present-day river-based hydrogen-isotope lapse rates are very low, possibly due to deep-convective seasonal storms that dominate runoff. If not accounted for, the effects of such conditions on moisture availability in the past may lead to misinterpretations of proxy-records of rainfall. Here, we present hydrogen-isotope data of volcanic glass (δDg), extracted from 34 volcanic ash layers in different sedimentary basins of the Eastern Cordillera and the Sierras Pampeanas. Combined with previously published δDg records and our refined U-Pb and (U-Th)/He zircon geochronology on 17 tuff samples, we demonstrate hydrogen-isotope variations associated with paleoenvironmental change in the Angastaco Basin, which evolved from a contiguous foreland to a fault-bounded intermontane basin during the late Mio

  14. Mineralogical and geochemical characters of surface sediments from the central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Banerjee, R.

    and siliceous sediments of the northern part of the basin indicate the influence of continental influx. This influence, however, decreases in the southern part of the basin where smectite is predominant, indicating volcanic input. The basinal sediments...

  15. The evolution of the Thuringian Syncline (Central Germany) - an interdisciplinary approach to basin reconstruction

    Science.gov (United States)

    Malz, Alexander; Beyer, Daniel; Donndorf, Stephan; Navabpour, Payman; Voigt, Thomas; Aehnelt, Michaela; Kley, Jonas

    2014-05-01

    The Thuringian Syncline is a shallow synform of mainly Triassic strata in Central Germany. In general, its lithostratigraphic units are similar to that of the North German Basin. On the top of the Paleozoic basement and Permocarboniferous red beds the evaporites of the late Permian Zechstein were deposited. The Triassic super group consists of fluvial to lacustrine sandstones, shale and evaporites of the Buntsandstein group, limestone, marls and evaporites of the marine Muschelkalk group and pelitic to sandy fluvial deposits and evaporite of the Keuper group. Some relicts of Lower Jurassic deposits still cover this succession. A number of NW-SE-trending fault zones with mostly small normal offsets characterize the recent structural configuration of the Thuringian Syncline. From regional correlations, and Lower Jurassic strata affected by normal faults, the extension most likely occurred in Late Jurassic to Early Cretaceous time. Some of these normal faults were reactivated as reverse faults during a phase of contraction in the Late Cretaceous. The unknown original offsets of the normal faults and the absence of syntectonic strata deposited during extension and contraction, however, make reconstruction of the graben inversion difficult to detect. In this study we try to reconstruct the structural evolution of the Thuringian Syncline based on structural observations, detailed map analysis, interpolations of stratigraphic surfaces at depth, cross section balancing and fault slip data analysis. Vitrinite reflectance data are used to estimate the maximum thickness of the eroded overburden. Our study identified a deep, extended and later inverted palaeo-depression in the central part of the Thuringian Syncline. We show that the recent structural configuration cannot explain variations of the thermal maturity without deriving specific thickness variations in the eroded overburden. Taking in consideration that many Central European faults, formerly interpreted as purely

  16. Estudos etnoictiológicos sobre o pirarucu Arapaima gigas na Amazônia Central Ethnoictiology studies on Pirarucu (Arapaima mock-ups in Central Amazon

    Directory of Open Access Journals (Sweden)

    Liane Galvão de Lima

    2012-09-01

    Full Text Available O presente estudo visou identificar saberes comuns entre o conhecimento científico e o conhecimento local sobre a ecologia e biologia do pirarucu (Arapaima gigas, contribuindo com informações úteis para a implementação e consolidação de projetos de manejo participativo pesqueiro na região. Foram realizadas 57 entrevistas semi-estruturadas, com pescadores profissionais de Manaus e pescadores de subsistência de Manacapuru durante o período de junho a dezembro do ano de 2002. Foi observado que os pescadores profissionais possuem informações igualmente precisas e abrangentes em relação aos saberes dos pescadores ribeirinhos de subsistência nos aspectos de reprodução, predação, migração, crescimento e mortalidade. Os aspectos que não são equivalentes entre os pescadores profissionais comerciais citadinos e ribeirinhos de subsistência são nos aspectos de tipo de alimentação e no tamanho de recrutamento pesqueiro. Concluímos que os pescadores da Amazônia central possuem os conhecimentos necessários que possibilitam o manejo participativo do pirarucu, como um profundo saber nos aspectos comportamentais, biológicos e ecológicos desta espécie, podendo assim contribuir de fato com a participação de gestão nos recursos pesqueiros locais.Present study it aimed at to identify to know common between scientific knowledge and local knowledge on ecology and biology of pirarucu (Arapaima mock-ups, contributing with useful information for implementation and consolidation of projects of participative handling fishing boat in region. 57 half-structuralized interviews had been carried through, with fishing of Manaus and Manacapuru during period of June to December of year 2002. It was observed that professional fishermen also have accurate and comprehensive information in relation to knowledge of subsistence fishermen in coastal aspects of reproduction, predation, migration, growth and mortality. Aspects that are not equivalent

  17. Seismic stratigraphy of middle Cretaceous unconformity (MCU) in central Gulf of Mexico basin

    Energy Technology Data Exchange (ETDEWEB)

    Faust, M.J.

    1986-05-01

    A widespread high-amplitude reflector seen on seismic data throughout the Gulf of Mexico has been called the middle Cretaceous unconformity (MCU). This reflector seems to be a major stratigraphic boundary in the Gulf of Mexico basin. It is believed to correspond to Vail's type 1 unconformity of middle Cenomanian age (97 Ma), which records an eustatic drop in sea level of approximately 200 m. This study area includes the entire Gulf of Mexico, except areas of thick, highly deformed salt where following the MCU with any degree of confidence becomes impossible. The MCU is easy to follow in multichannel seismic reflection profiles collected by the Institute for Geophysics of the University of Texas at Austin in the Gulf of Mexico. In central, deeper part of the gulf, reflectors above and below the MCU are parallel. In the southern and eastern rims of the gulf, along the Campeche and Florida escarpments, reflectors are truncated below the MCU and show onlap relationships above it. Therefore, the MCU may be interpreted as representing an unconformity along the southern and eastern rims of the Gulf of Mexico basin. The unconformity appears to die out and grade into a conformable section toward the center of the basin, and channeling is common along the Campeche and Florida escarpments. These channels can be projected back into canyons in the escarpments, which were probably initiated by subaerial exposure of the top of the escarpments during the middle Cretaceous lowstand. The downslope channels, being sourced by the canyons, were cut in deep water.

  18. 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)

  19. Basin Analysis and Petroleum System Characterization and Modeling, Interior Salt Basins, Central and Eastern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ernest A. Mancini; Paul Aharon; Donald A. Goddard; Roger Barnaby

    2006-05-26

    The principal research effort for Phase 1 (Concept Development) of the project has been data compilation; determination of the tectonic, depositional, burial, and thermal maturation histories of the North Louisiana Salt Basin; basin modeling (geohistory, thermal maturation, hydrocarbon expulsion); petroleum system identification; comparative basin evaluation; and resource assessment. Existing information on the North Louisiana Salt Basin has been evaluated, an electronic database has been developed, and regional cross sections have been prepared. Structure, isopach and formation lithology maps have been constructed, and burial history, thermal maturation history, and hydrocarbon expulsion profiles have been prepared. Seismic data, cross sections, subsurface maps and burial history, thermal maturation history, and hydrocarbon expulsion profiles have been used in evaluating the tectonic, depositional, burial and thermal maturation histories of the basin. Oil and gas reservoirs have been found to be associated with salt-supported anticlinal and domal features (salt pillows, turtle structures and piercement domes); with normal faulting associated with the northern basin margin and listric down-to-the-basin faults (state-line fault complex) and faulted salt features; and with combination structural and stratigraphic features (Sabine and Monroe Uplifts) and monoclinal features with lithologic variations. Petroleum reservoirs include Upper Jurassic and Cretaceous fluvial-deltaic sandstone facies; shoreline, marine bar and shallow shelf sandstone facies; and carbonate shoal, shelf and reef facies. Cretaceous unconformities significantly contribute to the hydrocarbon trapping mechanism capacity in the North Louisiana Salt Basin. The chief petroleum source rock in this basin is Upper Jurassic Smackover lime mudstone beds. The generation of hydrocarbons from Smackover lime mudstone was initiated during the Early Cretaceous and continued into the Tertiary. Hydrocarbon

  20. Correlation of the oldest Toba Tuff to sediments in the central Indian Ocean Basin

    Indian Academy of Sciences (India)

    J N Pattan; M Shyam Prasad; E V S S K Babu

    2010-08-01

    We have identified an ash layer in association with Australasian microtektites of ∼0.77Ma old in two sediment cores which are ∼450 km apart in the central Indian Ocean Basin (CIOB). Morphology and chemical composition of glass shards and associated microtektites have been used to trace their provenance. In ODP site 758 from Ninetyeast Ridge, ash layer-D (13 cm thick, 0.73–0.75 Ma) and layer-E (5 cm thick, 0.77–0.78 Ma) were previously correlated to the oldest Toba Tuff (OTT) eruptions of the Toba caldera, Sumatra. In this investigation, we found tephra ∼3100 km to the southwest of Toba caldera that is chemically identical to layer D of ODP site 758 and ash in the South China Sea correlated to the OTT. Layer E is not present in the CIOB or other ocean basins. The occurrence of tephra correlating to layer D suggests a widespread distribution of OTT tephra (∼3.6 × 107 km2), an ash volume of at least ∼1800 km3, a total OTT volume of 2300 km3, and classification of the OTT eruption as a super-eruption.

  1. Paleoclimatic variations in Maknassy Basin (central Tunisia) during the Holocene period using multidisciplinary approaches

    International Nuclear Information System (INIS)

    The signature of humid climatic episodes in the Holocene paleoclimatic history of Tunisia are evident in outcroppings along riverbanks almost all over the Tunisian drainage network. Previous multidisciplinary studies have already identified some sites where these remnants can contribute valuable information for reconstruction of paleoenvironmental and paleoclimatic variations in the presently hyper-arid zone of the Northern Sahara. Sedimentary deposits outcropping on Wadi Leben and Wadi Ben Sellam banks, in the Maknassy Basin (Central Tunisia), have been sampled. Multidisciplinary studies, including prehistory, sedimentology, mineralogy, ecology and radiochronology have been conducted to improve palaeoenvironmental interpretations and to determine a precise chronological history of humid episodes during the Holocene in Tunisia. This paper deals with the interpretation of results obtained from the Maknassy Basin in comparison with some other Tunisian sites in order to highlight Holocene humid episodes. Establishment of a precise chronological framework is prerequisite to exploring potential relationships between the occurrence of humid phases and recharge of aquifers located in this area. (author)

  2. Magnetic anomalies across Bastar craton and Pranhita–Godavari basin in south of central India

    Indian Academy of Sciences (India)

    I V Radhakrishna Murthy; S Bangaru Babu

    2009-02-01

    Aeromagnetic anomalies over Bastar craton and Pranhita –Godavari (P –G)basin in the south of central India could be attributed to NW –SE striking mafic intrusives in both the areas at variable depths.Such intrusions can be explained considering the collision of the Bastar and Dharwar cratons by the end of the Archaean and the development of tensile regimes that followed in the Paleoproterozoic,facilitating intrusions of mafic dykes into the continental crust.The P –G basin area,being a zone of crustal weakness along the contact of the Bastar and Dharwar cratons, also experienced extensional tectonics.The inferred remanent magnetization of these dykes dips upwards and it is such that the dykes are oriented towards the east of the magnetic north at the time of their formation compared to their present NW –SE strike.Assuming that there was no imprint of magnetization of a later date,it is concluded that the Indian plate was located in the southern hemisphere,either independently or as part of a supercontinent,for some span of time during Paleoproterozoic and was involved in complex path of movement and rotation subsequently. The paper presents a case study of the utility of aeromagnetic anomalies in qualitatively deducing the palaeopositions of the landmasses from the interpreted remanent magnetism of buried intrusive bodies.

  3. Quaternary Geology and Geomorphology of Terna River Basin in West Central India

    Directory of Open Access Journals (Sweden)

    Mohammad Babar

    2012-12-01

    Full Text Available This paper presents the morphostratigraphy, lithostratigraphy and sedimentary structures of Terna River basin in the Deccan Basaltic Province (DBP of West Central India. These Quaternary deposits have been divided into three informal formations (i dark grey silt formation – Late Holocene, (ii Light grey silt formations – Early Holocene, (iii Dark grayish brown silt formation – Late Pleistocene with the older Quaternary Alluvial deposits of Upper Pleistocene age. The fine clay and silt formations in the lower reaches reflect that the streams are of low gradient and more sinuous. The river shows evidences of channel movement by avulsion, largely controlled by lineaments. Palaeo-levees, in the form 4–5 m high ridges exist along the Terna River floodplain, specifically in the Ter, Killari, Sastur, Dhuta and Makni villages. Several lineaments occur along NE-SW, NW-SE, E-W and WNW-ESE directions, which control the basement structure in the study area. The values of the Topographic Sinuosity Index (TSI indicate rejuvenation of the area leading to the dominance of topography on the sinuosity of the river channels. The break in slope in the long profile is also indication of the Quaternary tectonic uplift of the area. Radiocarbon dating of some charcoal fragments collected from folded beddings indicates that paleoseismic activity might have taken place along the basin between AD 120 and AD 1671.

  4. Radiocarbon age distribution of groundwater in the Konya Closed Basin, central Anatolia, Turkey

    Science.gov (United States)

    Bayari, C. Serdar; Ozyurt, N. Nur; Kilani, Susan

    2009-03-01

    Annual abstraction of 2.6 × 109 m3 of groundwater in the 53,000 km2 Konya Closed Basin of central Turkey has caused a head decline of 1 m/year over the last few decades. Therefore, understanding the hydrogeology of this large endorheic basin, in a semi-arid climate, is important to sustainable resource management. For this purpose, the groundwater’s radiocarbon age distribution has been investigated along a 150-km transect parallel to regional flow. Results show that the groundwater ranges in age from Recent at the main recharge area of the Taurus Mountains in the south, to about 40,000 years around the terminal Salt Lake located in the north. In this predominantly confined flow system, radiocarbon ages increase linearly by distance from the main recharge area and are in agreement with the hydraulic ages. The mean velocity of regional groundwater flow (3 m/year) is determined by the rate of regional groundwater discharge into the Salt Lake. Calcite dissolution, dedolomitization and geogenic carbon dioxide influx appear to be the dominant geochemical processes that determine the carbon isotope composition along the regional flow path. The groundwater’s oxygen-18 content indicates more humid and cooler paleorecharge. A maximum drop of 5°C is inferred for the past recharge temperature.

  5. The organic geochemistry of the Eocene-Oligocene black shales from the Lunpola Basin, central Tibet

    Science.gov (United States)

    Sun, Tao; Wang, Chengshan; Duan, Yi; Li, Yalin; Hu, Bin

    2014-01-01

    This paper reports on the depositional paleoenvironment and the potential hydrocarbons of the Eocene-Oligocene black shales from the Dingqinghu and Niubao Formations in the Lunpola Basin, central Tibet. Nineteen samples from two outcrop profiles were analysed. The contents of the total organic carbon (TOC) and sulphur were measured; other analyses included Rock-Eval pyrolysis, solvent extraction and gas chromatography-mass spectrometer (GC-MS). The results indicated that the shales from the Dingqinghu and Niubao Formations are thermally immature. The pyrolysis data show that the shales contain Type I organic matter and that lacustrine algal are the main organic matter sources. The low pristane to phytane ratios and the high gammacerane indices indicate that the shales were deposited in a reducing, stratified, and hypersaline palaeo-lake, which is consistent with the climate information provided by the development history of palaeo-lakes from the Eocene to the Oligocene epochs.

  6. Group classification of mixed oils in central Junggar Basin, Northwest China and their migration

    Institute of Scientific and Technical Information of China (English)

    WANG Xulong; SHI Xinpu; CAO Jian; LAN Wenfang; TAO Guoliang; HU Wenxuan; YAO Suping

    2010-01-01

    The produced oils in central Junggar Basin are commonly mixed in origin. In this paper, in order to reveal this complexity and thereby provide valuable clues to the study of oil source and formation mechanism, genetic groups of the mixed oils were classified and their migration/accumulation was investigated. Based on the artificial oil mixing experiments, some representative biomarkers of the mixed oils showed varying tendencies according to mixing ratios of the oils. Hence, these biomarkers are useful for determining the origin of the mixed oils. According to the criteria, oils in the area were divided into four basic groups, i.e., the Lower Permian Fengcheng oil, the Middle Permian Lower Wuerhe oil, the Jurassic source derived oil, and the mixed oil (including the Lower and Middle Permian mixed oil and the Permian and Jurassic mixed oil). Oil migration and accumulation were discussed in combination with the geological background.

  7. Macrofossil evidence for pre-settlement vegetation of Central Otago's basin floors and gorges

    International Nuclear Information System (INIS)

    Composition of pre-settlement vegetation communities in the semi-arid Central Otago lowlands has been one of New Zealand's long-standing ecological puzzles. Uncertainty is due largely to a paucity of fossil data. Here, we provide new evidence for pre-settlement vegetation in the region based on analyses of plant macrofossils from 15 late Pleistocene and Holocene lowland sites. The assemblages represent two habitat types: wooded or partially wooded intermontane basin-floor wetlands, and low forest and/or shrubland habitats in the Kawarau and Clutha River gorges. In both habitat types, plant communities appear to have been predominantly woody, with significant components of herbaceous dicotyledons but few grasses. Both habitats seem to have undergone major post-settlement vegetation transformation. Several presently common taxa were rare or absent before human settlement, but others (including threatened spring annuals), now rare or extinct in the region, were formerly more common. (author). 57 refs., 5 figs., 3 tabs

  8. Early human occupation and land use changes near the boundary of the Orinoco and the Amazon basins (SE Venezuela): Palynological evidence from El Paují record

    OpenAIRE

    Montoya, Encarnación; Rull, Valentí; Nogué, Sandra

    2011-01-01

    This paper shows a Holocene paleoecological reconstruction based on a peat bog sequence (El Paují, 4°28′N–61°35′ W, 865 m elevation) located in the transition zone between the Gran Sabana (SE Venezuela) savannas and the Amazon rainforests. Paleoecological trends are based on the analysis of pollen and pteridophyte spores, algal and animal remains, fungal spores, and charcoal particles. Thewhole record embraces the last ca. 8000 cal yr BP, and was subdivided into five pollen zones, representin...

  9. Interpretation of seismic reflection data, Central Palo Duro Basin: Technical report

    International Nuclear Information System (INIS)

    Seismic reflection data from the Central Palo Duro Basin, Texas, were studied to identify and characterize geologic structure, potential hydrocarbon traps, and anomalies suggesting adverse features such as salt dissolution or diapirism. The data included seismic reflection data, geologic and geophysical data controlled by Stone and Webster Engineering Corporation, and data from the literature. These data comprised approximately 590 line-mi of seismic profiles over approximately 4000 mi2, plus well logs from 308 wells. The study addressed the section from shallow reflectors down to basement. Structural contour maps were prepared for the Upper San Andres, Near Top of Glorieta, Wolfcamp, and Precambrian horizons. Isopach maps were prepared for intervals between the Upper and Lower San Andres and between the Upper San Andres and the Wolfcamp. Interpretation indicates southeasterly dips in the northwest part of the mapped area and southwesterly dips in the southwest part. Geologic structures show a generally northwest alignment. Faults at the Precambrian level and geologic structures show a generally northwest alignment. Faulting in the area is largely limited to the Precambrian, but interpretation is uncertain. Evidence of post-Wolfcampian faulting is not recognized. Seismic data delineating the San Andres section indicate a stable section throughout the area. Anomalous reflection events possibly associated with subsurface salt dissolution were seen at the 800- to 1200-ft level in Swisher County. Other anomalies include an overthickened zone northwest of Westway and carbonate buildup in the Wolfcamp and Pennsylvanian in Randall County. Mississippian to Middle Pennsylvanian diastrophism resulting in the Amarillo Uplift and Matador Arch is not manifested structurally in the central Palo Duro Basin. Subsidence or gentle uplift contributed to some structural deformation

  10. BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

    Energy Technology Data Exchange (ETDEWEB)

    Ernest A. Mancini; Donald A. Goddard; Ronald K. Zimmerman

    2005-05-10

    The principal research effort for Year 2 of the project has been data compilation and the determination of the burial and thermal maturation histories of the North Louisiana Salt Basin and basin modeling and petroleum system identification. In the first nine (9) months of Year 2, the research focus was on the determination of the burial and thermal maturation histories, and during the remainder of the year the emphasis has basin modeling and petroleum system identification. Existing information on the North Louisiana Salt Basin has been evaluated, an electronic database has been developed, regional cross sections have been prepared, structure and isopach maps have been constructed, and burial history, thermal maturation history and hydrocarbon expulsion profiles have been prepared. Seismic data, cross sections, subsurface maps and related profiles have been used in evaluating the tectonic, depositional, burial and thermal maturation histories of the basin. Oil and gas reservoirs have been found to be associated with salt-supported anticlinal and domal features (salt pillows, turtle structures and piercement domes); with normal faulting associated with the northern basin margin and listric down-to-the-basin faults (state-line fault complex) and faulted salt features; and with combination structural and stratigraphic features (Sabine and Monroe Uplifts) and monoclinal features with lithologic variations. Petroleum reservoirs are mainly Upper Jurassic and Lower Cretaceous fluvial-deltaic sandstone facies and Lower Cretaceous and Upper Cretaceous shoreline, marine bar and shallow shelf sandstone facies. Cretaceous unconformities significantly contribute to the hydrocarbon trapping mechanism capacity in the North Louisiana Salt Basin. The chief petroleum source rock in this basin is Upper Jurassic Smackover lime mudstone beds. The generation of hydrocarbons from Smackover lime mudstone was initiated during the Early Cretaceous and continued into the Tertiary

  11. Extensional Basins in a Convergent Margin: Oligocene-Early Miocene Salar de Atacama and Calama basins, Central Andes

    Science.gov (United States)

    Jordan, T. E.; Mpodozis, C.; Blanco, N.; Pananont, P.; Dávila, F.

    2004-12-01

    The Salar de Atacama Basin (SdAB) is the largest and most persistent sedimentary basin of northern Chile, accumulating nonmarine sediment from Cretaceous to modern times. Its northwestern neighbor, the Calama, was a Cenozoic basin. Although SdAB was in the backarc zone early in the Andean orogeny, both are now forearc basins. Others demonstrated that the basins overlie anomalously cold, strong, and dense crust and lithosphere. We focus on an extensional Oligocene basin stage. Interpretation of the basin-controlling faults is based on seismic reflection studies supported by field relations. The SdAB is limited to the west by the NNE-trending, steeply east-dipping, Paciencia Fault (PF). The PF experienced 5-7 km of down-to-the-east offset during the Oligocene-early Miocene. Syntectonic strata, an arid succession of siliciclastics and evaporites, are asymmetric, with thicknesses of 5000 m and abundant halite adjacent to the PF, and of 1000 m with fine detrital clastic strata 25 km farther east. Relations in conglomeratic growth strata that overlap the PF also demonstrate normal displacement during sediment accumulation. Seismic data reveal that a buried normal fault with 1-1.5 km down-to-the-east displacement limits the western margin of the Oligocene-Miocene Calama siliciclastic basin fill. Regionally, Oligocene-early Miocene margin-parallel strike-slip deformation dominated northwest of the basins, contributing sinistral offset (West Fissure Fault) to the northern segment of the long-lived Domeyko Fault System. The new SdAB and Calama data reveal that a 20,000 km2 domain of extensional basins existed within the dominantly strike-slip region. Even if PF and the fault in the Calama Basin were transtensional, the proportion of extension to strike-slip displacement is much greater in these basins than elsewhere in northern Chile. Further study is required to understand what combination of factors caused this kinematic distinction as well as delayed the onset of CVZ

  12. Basin Analysis and Petroleum System Characterization and Modeling, Interior Salt Basins, Central and Eastern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ernest A. Mancini

    2005-03-31

    The principal research effort for Year 2 of the project is the determination of the burial and thermal maturation histories and basin modeling and petroleum system identification of the North Louisiana Salt Basin. In the first six (6) to nine (9) months of Year 2, the research focus is on the determination of the burial and thermal maturation histories and the remainder of the year the emphasis is on basin modeling and petroleum system identification. No major problems have been encountered to date, and the project is on schedule.

  13. BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

    Energy Technology Data Exchange (ETDEWEB)

    Ernest A. Mancini

    2004-11-05

    The principal research effort for Year 2 of the project is the determination of the burial and thermal maturation histories and basin modeling and petroleum system identification of the North Louisiana Salt Basin. In the first six (6) to nine (9) months of Year 2, the research focus is on the determination of the burial and thermal maturation histories and the remainder of the year the emphasis is on basin modeling and petroleum system identification. No major problems have been encountered to date, and the project is on schedule.

  14. Implementation of MAR within the Rio Grande Basin of Central New Mexico, USA

    Science.gov (United States)

    Marley, Robert; Blandford, T. Neil; Ewing, Amy; Webb, Larry; Yuhas, Katherine

    2014-05-01

    The U.S. Bureau of Reclamation has identified the Rio Grande basin within Central New Mexico as one of several regions where water supplies are over-allocated and future conflicts over the inadequate resource are highly likely. Local water providers have consistently identified managed aquifer recharge (MAR) as an important tool to provide conjunctive management of surface-water, groundwater, and reclaimed water sources in order to extend the useful life of existing water sources. However, MAR projects have been slow to take root partly due to rigorous demonstration requirements, groundwater quality protection concerns, and ongoing water right uncertainties. At first glance the several thousand meters of unconsolidated basin-fill sediments hosting the regional aquifer appear to provide an ideal environment for the subsurface storage of surplus water. However, the basin has a complex structural and depositional history that impacts the siting and overall effectiveness of MAR systems. Several recharge projects are now in various stages of implementation and are overcoming site specific challenges including source water and ambient groundwater compatibility, low-permeability sediments and compartmentalization of the aquifer by extensive faulting, well clogging, and overall water quality management. This presentation will highlight ongoing efforts of these water providers to develop full-scale recharge facilities. The performance of natural in-channel infiltration, engineered infiltration galleries, and direct injection systems designed to introduce from 500 to 5,000 mega-liters per annum to target intervals present from 150 to 600 meters below ground surface will be described. Source waters for recharge operations include inter-basin transferred surface water and highly treated reclaimed water sources requiring from minor to extensive treatment pre-recharge and post-recovery. Operational complexities have raised concerns related to long-term operation and maintenance

  15. Latest Permian to Middle Triassic cyclo-magnetostratigraphy from the Central European Basin, Germany: Implications for the geomagnetic polarity timescale

    OpenAIRE

    Michael Szurlies

    2007-01-01

    In Central Germany, the about 1 km thick mainly clastic Germanic Lower Triassic (Buntsandstein) consists of about 60 sedimentary cycles, which are considered to reflect variability in precipitation within the epicontinental Central European Basin, most probably due to solar-induced short eccentricity cycles. They provide a high-resolution cyclostratigraphic framework that constitutes the base for creating a composite geomagnetic polarity record, in which this paper presents a Middle Buntsands...

  16. Regional analysis of changes in snow pack in mountainous basins in the central Danube region

    Science.gov (United States)

    Balint, Gabor; Juričeková, Katarina; Gauzer, Balazs; Hlavčová, Kamila; Kohnová, Silvia; Szolgay, Jan; Zsideková, Beata

    2013-04-01

    Accurate estimation of the volume of water stored in the snow pack and its rate of release is essential to predict the flow during the snowmelt period. In mountainous drainage basins water stored in the snow pack represents an important component of the water budget. Two modelling tools are compared. The first, HOLV snowmelt model is developed by the Hungarian National Hydrological Forecasting Service (VITUKI NHFS) for regional assessment of snow accumulation and ablation of the central Danube. The model originates from the early 80's and it is under continuous development, while its recent distributed version over a grid with 0.1 degree resolution is in use. The snowmelt model has a flexible structure; it is able to change its own structure in function of data availability. In case when only precipitation and air temperature data are available temperature index method is used. When also other data are accessible (cloudiness, dew point, wind speed) using of energy balance model is to be preferred. If there are suitable data available for calculation of the energy terms, the energy balance method can be applied. The second semi-distributed Hron model, developed at the Slovak University of Technology was applied to a smaller sub-basin to represent spatial distribution of snow cover by simulated snow water equivalent. The upper Hron river basin with an area of 1766 km2 is located in central Slovakia. The conceptual semi-distributed tool applied contains three basic storage components with 15 calibrated parameters, as the flow routing component the cascade of linear reservoirs is used as opposed to the original simple triangular routing function. The snow sub-model uses the temperature index (degree-day) method for snow accumulation and snowmelt calculations. Uncertainty of model parameters was reduced by multi-calibration on the mean daily discharges in the basin outlet and measured stations data of snow water equivalent. Changes in the model parameters during the

  17. Gravity modeling constraints on the Gatun-Chagres Basin and tectonic evolution of north-central Panama

    Science.gov (United States)

    Mynhier, Kelci

    The Oligocene-Miocene collision between Panama and South America significantly influenced ocean currents, global climate, and species diversification. Intraplate deformation of the Panama Block also played an important role in the evolution of this tectonic system, but is not well understood. A high-resolution gravity survey, coupled with geologic observations, was conducted in north-central Panama to better constrain the processes responsible for the Isthmus' modern configuration. Approximately 110 gravity stations were collected from Colon to Nombre de Dios, Panama and merged with existing data. Subsequently, four 2.5-D gravity models were produced to constrain the geometry of the Gatun-Chagres Basin using different sedimentary densities (1.8, 2.0, and 2.2 g/cm 3) to produce a realistic range of basin thicknesses. Overall, models with an average basin density of 2.0 g/cm3 are most consistent with offshore seismic profiles and field evidence, suggesting basin thickness is ~3.0--3.5 km. Previous seismic reflection data and geochemical analyses of Miocene arc volcanic rocks delineate a zone of extension in the Panama Canal Region, and gravity analysis from this study supports this hypothesis. Field evidence of multiple NW-facing normal faults suggests that they separate the basin from uplifted arc basement rocks east of the Canal, resulting in a 60 mGal gravity gradient. Beneath the basin, gravity models indicate ~5--10 km of crustal thinning. 3-D reconstruction of the 2.5-D models show a northward thickening basin and two depocenters that correspond to the Rio Indio and Toro facies of the Chagres Formation. This analysis suggests two directional extension of the Gatun-Chagres Basin; an east-west direction corresponding to the initial formation of the basin, and a modern northwest-southeast direction. To the northeast, gravity modeling indicates that there is a ~150 m-thick, Cretaceous-Holocene sedimentary basin present from Portobelo to Nombre de Dios. Sedimentary

  18. What controls the interannual variation of the wet season onsets over the Amazon?

    Science.gov (United States)

    Yin, Lei; Fu, Rong; Zhang, Yong-Fei; Arias, Paola A.; Fernando, D. Nelun; Li, Wenhong; Fernandes, Katia; Bowerman, Adam R.

    2014-03-01

    Previous studies have established that sea surface temperature anomalies (SSTAs) in the tropical Pacific and Atlantic are the main forcing of the interannual variation of the wet season onsets in the Amazon. However, this variation appears to be complex and not uniquely determined by SSTAs. What causes such a complexity and to what extent the interannual variation of the wet season onsets is predictable remain unclear. This study suggests that such a complex relationship is the result of several competing processes, which are nonlinearly related to the SSTAs. In particular, three dry season conditions are crucial for determining interannual variation of the wet season onset. (i) A poleward shift of the Southern Hemisphere subtropical jet (SHSJ) over the South American sector, initiated from a wave train-like structure possibly forced by south central Pacific SST patterns, can prevent cold frontal systems from moving northward into the Amazon. This delays cold air incursion and results in late wet season onset over the southern Amazon. (ii) An anomalous anticyclonic center, which enhances westerly wind at 850 hPa over the southern Amazon and also the South American low-level jets, leads to moisture export from the southern Amazon to La Plata basin and reduces convective systems that provide elevated diabatic heating. (iii) Smaller convective available potential energy (CAPE) limits local thermodynamically driven convection. Based on the stepwise and partial least squares regressions, these three selected preseasonal conditions (Niño 4, SHSJ, and CAPE) can explain 57% of the total variance of the wet season onset.

  19. 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.

  20. Determinação de idade e crescimento do mapará (Hypophthalmus marginatus na Amazônia Central Age and growth of mapará (Hypophthalmus marginatus in the Central Amazon

    Directory of Open Access Journals (Sweden)

    Leocy Cutrim

    2005-01-01

    Full Text Available O presente trabalho visa contribuir para a conservação e manejo do mapará (Hypophthalmus marginatus, um importante recurso pesqueiro de exportação do Amazonas para o qual é necessário conhecer informações essenciais de sua dinâmica de populações. Para contribuir à esta finalidade, o presente trabalho estabeleceu como objetivo identificar o par de otólito mais adequado para leitura de anéis etários, determinar os parâmetros de crescimento do mapará (H. marginatus, Amazônia Central, Amazonas - Brasil. O trabalho foi efetuado através da análise de otólitos coletados no período de dezembro de 1996 á agosto de 1997. Os otólitos escolhidos foram os asteriscus, sendo a leitura efetuada em lupa estereoscópica com monitor acoplado. As marcas de crescimento foram validadas por meio da análise do incremento marginal relativo, sendo encontrado dois anéis/ano. Os valores estimados para os parâmetros no período foram L¥ = 52,63 cm; k = 0,555 ano; to = -0,029 e M = 0,552. O ciclo hidrológico e comportamento reprodutivo estão relacionados com a marcação de anéis etários.The present work seeks to contribute for the conservation and management of the mapará(Hypophthalmus marginatus, an important export fishing resource of Amazonas for which is necessary to know essential information of its population dynamics. To contribute to this purpose, the present work established as objective to identify a structure for reading of age rings, to determine the parameters of growth of the mapará (H. marginatus, Central Amazon, Amazonas - Brazil. The work was made through the otoliths analysis collected in the period of December of 1996 to August of 1997. The otolith chosen for reading was the asteriscus, being the reading made in a stereomicroscope with coupled monitor. The mark structures were validated by means of the analysis of the relative marginal increment, being found two rings. The values estimated for the parameters in the

  1. Assessment of the invasive status of newly recorded cactus species in the central Tugela River basin

    Directory of Open Access Journals (Sweden)

    Michael D. Cheek

    2015-03-01

    Full Text Available Background: Current distribution information on cacti in the Tugela River basin in KwaZulu-Natal, South Africa, is scant. Accordingly, surveys in this region substantially improve our understanding of regional invasions by this succulent group. The identification of new or extended invasions requires (reassessments of their invasion status and consideration of possible management interventions.Objectives: To identify and collect cacti either not previously recorded or poorly known in the central Tugela River basin, and to assess their invasion status.Method: A 40 km section of tertiary road was travelled through the topocadastral square 2830 CC, from the R74 main road northward across the Bloukrans River towards the Tugela River. Herbarium specimens were collected to vouch for new instances of naturalisation of cacti, the colony sizes of which were estimated and invasion stages determined. An applicable weed risk assessment model was used to determine the threat status of one cactus species not previously evaluated for South Africa. Based on the South African Plant Invaders Atlas database records and field observations, management recommendations were suggested for six cacti species.Results: The first naturalised population of Opuntia microdasys in KwaZulu-Natal was detected, as was the first confirmed South African record of Echinopsis oxygona. Four populations of Peniocereus serpentinus were also found, ranging in size from several square metres to 0.4 ha. Echinopsis oxygona generated a score that falls into the reject category of the risk assessment model used.Conclusion: It is recommended that E. oxygona be added to the Species Under Surveillance for Possible Eradication or Containment Targeting list to investigate whether this species requires formal legal listing and the development of a specific eradication plan. Immediate action from local authorities is recommended for the manual removal of P. serpentinus and O. microdasys populations.

  2. A key continental archive for the last 2 Ma of climatic history of the central Mediterranean region: A pilot drilling in the Fucino Basin, central Italy

    Science.gov (United States)

    Giaccio, B.; Regattieri, E.; Zanchetta, G.; Wagner, B.; Galli, P.; Mannella, G.; Niespolo, E.; Peronace, E.; Renne, P. R.; Nomade, S.; Cavinato, G. P.; Messina, P.; Sposato, A.; Boschi, C.; Florindo, F.; Marra, F.; Sadori, L.

    2015-12-01

    An 82 m long sedimentary succession was retrieved from the Fucino Basin, the largest intermountain tectonic depression of the central Apennines. The basin hosts a succession of fine-grained lacustrine sediments (ca. 900 m-thick) possibly continuously spanning the last 2 Ma. A preliminary tephrostratigraphy study allows us to ascribe the drilled 82 m long record to the last 180 ka. Multi-proxy geochemical analyses (XRF scanning, total organic/inorganic carbon, nitrogen and sulfur, oxygen isotopes) reveal noticeable variations, which are interpreted as paleohydrological and paleoenvironmental expressions related to classical glacial-interglacial cycles from the marine isotope stage (MIS) 6 to present day. In light of the preliminary results, the Fucino sedimentary succession is likely to provide a long, continuous, sensitive, and independently dated paleoclimatic archive of the central Mediterranean area.

  3. 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

    2009-03-01

    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.

  4. 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.

  5. Hydrological impact of rainwater harvesting in the Modder river basin of central South Africa

    Directory of Open Access Journals (Sweden)

    W. A. Welderufael

    2011-05-01

    Full Text Available Along the path of water flowing in a river basin are many water-related human interventions that modify the natural systems. Rainwater harvesting is one such intervention that involves harnessing of water in the upstream catchment. Increased water usage at upstream level is an issue of concern for downstream water availability to sustain ecosystem services. The upstream Modder River basin, located in a semi arid region in the central South Africa, is experiencing intermittent meteorological droughts causing water shortages for agriculture, livestock and domestic purpose. To address this problem a technique was developed for small scale farmers with the objective of harnessing rainwater for crop production. However, the hydrological impact of a wider adoption of this technique by farmers has not been well quantified. In this regard, the SWAT hydrological model was used to simulate the hydrological impact of such practices. The scenarios studied were: (1 Baseline scenario, based on the actual land use of 2000, which is dominated by pasture (combination of natural and some improved grass lands (PAST; (2 Partial conversion of Land use 2000 (PAST to conventional agriculture (Agri-CON; and (3 Partial conversion of Land use 2000 (PAST to in-field rainwater harvesting which was aimed at improving the precipitation use efficiency (Agri-IRWH.

    SWAT was calibrated using observed daily mean stream flow data of a sub-catchment (419 km2 in the study area. SWAT performed well in simulating the stream flow giving Nash and Sutcliffe (1970 efficiency index of 0.57 for the monthly stream flow calibration. The simulated water balance results showed that the highest peak mean monthly direct flow was obtained on Agri-CON land use (18 mm, followed by PAST (12 mm and Agri-IRWH land use (9 mm. These were 19 %, 13 % and 11 % of the mean annual rainfall, respectively. The Agri-IRWH scenario reduced direct flow by 38 % compared to Agri-CON. On the other

  6. Declining fertility on the frontier: the Ecuadorian Amazon

    OpenAIRE

    Carr, David L.; Pan, William K. Y.; Bilsborrow, Richard E.

    2006-01-01

    This paper examines farm and household characteristics associated with a rapid fertility decline in a forest frontier of the Ecuadorian Amazon. The Amazon basin and other rainforests in the tropics are among the last frontiers in the ongoing global fertility transition. The pace of this transition along agricultural frontiers will likely have major implications for future forest transitions, rural development, and ultimately urbanization in frontier areas. The study here is based upon data fr...

  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...... villagers, the great variation in the knowledge they possess, and the fact that the differences between villages is so great, are important elements to consider when developing management plans for the sustainable use of the rainforest resources in the western Amazon. Keywords  Local knowledge...... - Palms - Western Amazon - Ethno-botany - Socioeconomic factors...

  8. Radium and barium in the Amazon River system

    International Nuclear Information System (INIS)

    Data for 226Ra and 228Ra in the Amazon River system show that the activity of each radium isotope is strongly correlated with barium concentrations. Two trends are apparent, one for rivers which drain shield areas and another for all other rivers. These data suggest that there has been extensive fractionation of U, Th, and Ba during weathering in the Amazon basin. The 226Ra data fit a flux model for the major ions indicating that 226Ra behaves conservatively along the main channel of the Amazon River

  9. Trace elements distribution in the Amazon floodplain soils

    International Nuclear Information System (INIS)

    Neutron activation analysis was performed on aluvial soil samples from several sites on the foodplains of the Amazon River and its major tributaries for trace elements determination. The spatial and temporal variations of chemical composition of floodland sediments in the Amazon basin are discussed. No significant difference was found in trace elemental distribution in the floodland soils along the Amazon main channel, even after the source material has been progressively diluted with that from lowland draining tributaries. It was also seen that the average chemical composition of floodplain soils compares well with that of the suspended sedimets. (author) 12 refs.; 5 figs.; 2 tabs

  10. Carbon Tetrachloride Emissions from the Amazon Forest

    Science.gov (United States)

    Jardine, K.; Chambers, J. Q.; Higuchi, N.; Jardine, A. B.; Martin, S. T.; Manzi, A. O.

    2014-12-01

    As a chemically inert greenhouse gas in the troposphere with lifetimes up to 50 years but active in ozone destruction in the stratosphere, carbon tetrachloride (CCl4) plays a major role in the atmospheric chlorine budget and is widely considered strictly of anthropogenic origin deriving from numerous industrial processes and products. However, satellite remote sensing studies have shown higher concentrations at the Equator, and earlier work has suggested possible biogenic sources. Here we present highly vertically-resolved atmospheric gradients of CCl4 within and above a primary rainforest ecosystem from three towers in the Central Amazon. The observed buildup of CCl4 mixing ratios near the top of the main canopies provides new evidence for a potentially large biogenic source from the Basin. By demonstrating the need to represent tropical forests as biogenic sources of CCl4, our study may help narrow the gap between remote sensing observations of CCl4 and emission, chemistry, and transport models and therefore lead to improved predictions of its role in atmospheric chemistry and climate.

  11. A comprehensive approach to the 3D geological modelling of sedimentary basins: example of Latvia, the central part of the Baltic Basin

    Directory of Open Access Journals (Sweden)

    Konrāds Popovs

    2015-05-01

    Full Text Available This paper presents a semi-automatic approach adapted to the modelling of the geological structure of sedimentary basins. The modelling approach is based on developing the algorithm of the main geological processes so that the geometrical relationship is automatically defined between model elements. The algorithm is based on the assumption that sedimentary basins are formed as a result of the repeated sequence of sedimentation, faulting and erosion. This approach allows of successful modelling of the geological structure of the sedimentary basins with limited data coverage: stratigraphic intervals from well logs describing the thicknesses of sedimentary strata and a limited amount of structural data. Sedimentary layers are handled by modelling assuming non-eroded thickness distribution and using geometrical adjustment from the known fault displacements. As a result geometrical relationships of the model layers are deduced automatically in the presence of unconformities. An application of this methodology, a 3D geological model of Latvia, the central part of the Baltic Basin, is presented. The results show that this model is geologically reasonable for achieving the structural and stratigraphic concepts.

  12. Modeling Carbon Sequestration over the Large-Scale Amazon Basin, Aided by Satellite Observations. Part I: Wet- and Dry-Season Surface Radiation Budget Flux and Precipitation Variability Based on GOES Retrievals.

    Science.gov (United States)

    Gu, Jiujing; Smith, Eric A.; Cooper, Harry J.; Grose, Andrew; Liu, Guosheng; Merritt, James D.; Waterloo, Maarten J.; de Araújo, Alessandro C.; Nobre, Antonio D.; Manzi, Antonio O.; Marengo, Jose; de Oliveira, Paulo J.; von Randow, Celso; Norman, John; Silva Dias, Pedro

    2004-06-01

    detect rainfall processes, and yet they are responsive to the rapidly changing cloud fields, which are directly associated with precipitation life cycles over the Amazon basin. In conducting the validation analysis at high space time scales, the comparisons indicate systematic bias uncertainties on the order of 25%. These uncertainties are comparable to published values from an independent assessment of bias uncertainties inherent to the current highest-quality satellite retrievals, that is, from the Tropical Rainfall Measuring Mission. Because precipitation is a weak direct control on photosynthesis for the Amazon ecosystem, that is, photosynthesis is dominated by the strong diurnal controls of incoming PAR and ambient air-canopy temperatures, such uncertainties are tolerable. By the same token, precipitation is a strong control on soil thermal properties and carbon respiration through soil moisture, but the latter is a time-integrating variable and thus inhibits introduction of modeling errors caused by random errors in the precipitation forcing. The investigation concludes with analysis of the monthly, daily, and diurnal variations intrinsic to SRB and rainfall processes over the Amazon basin, including explanations of how these variations arise during wet- and dry-season periods.

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

    OpenAIRE

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

    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. Methodolog...

  14. Sedimentary characteristics of tide-dominated estuary in Donghetang Formation(Upper Devonian), central Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The Donghetang Formation (Upper Devonian) in central Tarim Basin has been thought an important oil and gas reservoir since the abundant oil and gas resources were found in the wells W16, W20, W34, and other fields. However, the sedimentary environment of the Donghetang Formation has been disputed because it suffered from both tidal and fluvial actions and there were not rich fossils in the sandstone. After the authors analyzed sedimentary features by means of drill cores, well logging data, paleosols, and with SEM obseruations, three kinds of sedimentary environments were distinguished: alluvial fan, tide-dominated estuary, and shelf. Particularly, the sedimentary features of tide-dominated estuary were studied in detail. Besides, the authors discussed sedimentary characteristics of the Donghetang Formation which was divided into two fourth-order sequences and five system tracts. At the same time, according to the forming process of five system tracts, the whole vertical evolution and lateral transition of tide-dominated estuary were illustrated clearly. Finally, the reservoir quality was evaluated based on porosity and permeability.

  15. Spatio-Temporal Variations and Source Apportionment of Water Pollution in Danjiangkou Reservoir Basin, Central China

    Directory of Open Access Journals (Sweden)

    Pan Chen

    2015-05-01

    Full Text Available Understanding the spatio-temporal variation and the potential source of water pollution could greatly improve our knowledge of human impacts on the environment. In this work, data of 11 water quality indices were collected during 2012–2014 at 10 monitoring sites in the mainstream and major tributaries of the Danjiangkou Reservoir Basin, Central China. The fuzzy comprehensive assessment (FCA, the cluster analysis (CA and the discriminant analysis (DA were used to assess the water pollution status and analyze its spatio-temporal variation. Ten sites were classified by the high pollution (HP region and the low pollution (LP region, while 12 months were divided into the wet season and the dry season. It was found that the HP region was mainly in the small tributaries with small drainage areas and low average annual discharges, and it was also found that most of these rivers went through urban areas with industrial and domestic sewages input into the water body. Principal component analysis/factor analysis (PCA/FA was applied to reveal potential pollution sources, whereas absolute principal component score-multiple linear regression (APCS-MLR was used to identify their contributions to each water quality variable. The study area was found as being generally affected by industrial and domestic sewage. Furthermore, the HP region was polluted by chemical industries, and the LP region was influenced by agricultural and livestock sewage.

  16. Characterization of photoautotrophic picoplankton assemblages in turbid, alkaline lakes of the Carpathian Basin (Central Europe

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    Lajos VÖRÖS

    2009-08-01

    Full Text Available The photoautotrophic picoplankton (PPP of ten shallow, hyposaline soda lakes located in three different geographical regions in the Carpathian Basin (Central Europe was characterized. These lakes, which frequently dry out completely, are extremely rich in PPP. Epifluorescence microscopy was applied to determine picocyanobacterial and picoeukaryotic cell abundance and PCR-based molecular techniques (denaturing gradient gel electrophoresis and cloning with phylospecies delineation to identify the members of PPP. Most of these lakes were eu- and hypertrophic with varying contribution of picocyanobacteria to the total PPP cell number. We found an unusually high PPP abundance with peaks of 8.16 × 106 cells mL-1 for picoeukaryotes and 1.78 × 107 cells mL-1 for picocyanobacteria. The majority of the retrieved PPP sequences belonged to picocyanobacteria (nonmarine Synechococcus/ Cyanobium, while others showed similarity to eukaryotic algal plastids (close to Trebouxiophycean isolates. Molecular analysis revealed significant genetic diversity in the PPP fraction of these lakes and showed that the closest relatives of our picocyanobacterial clones were recovered from different habitats, indicating seemingly no correlation between the 'saline' ecotypes and their phylogenetic position. Our results also confirmed that PPP might exploit different aquatic ecosystems and be successful even in the case of abrupt changes of environmental parameters (in our case, salinity. According to our knowledge, this is the first survey focusing on the identification of the PPP community members in turbid and alkaline lakes with extraordinarily high picoplankton productivity.

  17. Evolution of the Moxizhuang Oil Field, Central Junggar Basin, Northwest China

    Institute of Scientific and Technical Information of China (English)

    Zou Huayao; Zhang Yuanchun; Liu Jianzhang; Shi Jiannan

    2008-01-01

    Current oil saturation in the Moxizhuang (莫西庄) Oil Field in central Janggar (准噶尔) basin was evaluated by logging interpretation and measured on core samples, and the paleo-oil saturation in both the pay zones and water zones was investigated by graln-containing-oil inclusion (GOI) analysis.The pay zones in this field have low oil saturation and display low resistivity and small contrast between pay zones and water zones, and are classified as low-porosity, low oil saturation, and low resistivity reservoirs. Both the current low oil-saturation pay zones and the water zones above 4 365 m have high GOI values (up to 38%), suggesting high paleo-oil saturation. The significant difference between current oil saturation from both logging interpretation and core sample measurement and paleo-oil saturation indicated by GOI analysis suggests that this low oil-saturation field evolved from a high oil-saturation pool. Lateral re-migration and spill of formally trapped oil owing to changes in structural configuration since Neogene was the most plausible mechanism for oil loss in the Moxizhuang Oil Field.The combined effects of differential accumulation in the charge phase and the differential re-migration and spill of accumulated oil in Neogene are responsible for the complicated correlation between residual oil saturation and porosity/permeability of the reservoir sandstones and the distribution of low oil-saturation pay zones and paleo-oil zones (current water zones).

  18. Changes in Diversity of Fish Fauna of the Chu River Basin (Central Asia

    Directory of Open Access Journals (Sweden)

    Eleonora Byrlykzhanovna Kozhabaeva

    2015-11-01

    Full Text Available The Chu River originates in the Central Tien Shan Mountains and dissipates into the Muyunkum desert. The first information about the fish of the river was received in the middle 19-th century. Several expeditions collected data during 20-th century. Results of our investigations last decade in comparison with previous data allow tracking changes in the fish fauna after growing human impact. In the main, our data concern of the Kazakhstan part of the river. About 34 species and subspecies were discovered here; about 19 species between them are native. Origin or taxonomy of some species are disputable. In the last publications of the XX-th century 38 fish species and subspecies were mentioned. Native fish species as Aral barbel Barbus brachycephalus and Bulatmai barbel Barbus capito, Chu sharpray Capoetobrama kuschakewitschii and alien Sea trout Salmo trutta, Sevan trout Salmo ischchan were not found last decade in the Kazakhstan part of the river. Distribution area of native Balkhash marinka Schizothorax argentatus and alien Balkhash perch Perca schrenkii were reduced. The most widespread and numerous fish species are native roach, carp, dace, gudgeon and alien stone moroco. Native fishes like pike, asp, Aral ide, striped bystranka, golden spiny loach, southern ninespine stickleback and others were found only in certain sites. Fish species composition for each investigated site was not stable during recent years. Significant variations in fish composition were observed between different water bodies of the basin too. It reflects diversity of human impacts and unsteady water regimen here.

  19. Hydrogeochemical investigations in a drained lake area: the case of Xynias basin (Central Greece).

    Science.gov (United States)

    Charizopoulos, Nikos; Zagana, Eleni; Stamatis, Georgios

    2016-08-01

    In Xynias drained Lake Basin's area, central Greece, a hydrogeochemical research took place including groundwater sampling from 30 sampling sites, chemical analysis, and statistical analysis. Groundwaters present Ca-Mg-HCO3 as the dominant hydrochemical type, while their majority is mixed waters with non-dominant ion. They are classified as moderately hard to hard and are characterized by oxidizing conditions. They are undersaturated with respect to gypsum, anhydrite, fluorite, siderite, and magnesite and oversaturated in respect to calcite, aragonite, and dolomite. Nitrate concentration ranges from 4.4 to 107.4 mg/L, meanwhile 13.3 % of the samples exceed the European Community (E.C.) drinking water permissible limit. The trace elements Fe, Ni, Cr, and Cd present values of 30, 80, 57, and 50 %, respectively, above the maximum permissible limit set by E.C. Accordingly, the majority of the groundwaters are considered unsuitable for drinking water needs. Sodium adsorption ratio values (0.04-3.98) and the electrical conductivity (227-1200 μS/cm) classify groundwaters as suitable for irrigation uses, presenting low risk and medium soil alkalization risk. Factor analysis shows that geogenic processes associated with the former lacustrine environment and anthropogenic influences with the use of fertilizers are the major factors that characterized the chemical composition of the groundwaters. PMID:27450374

  20. Rainfall and land use empirically coupled to forecast landslides in the Esino river basin, central Italy

    Science.gov (United States)

    Gioia, E.; Carone, T.; Marincioni, F.

    2015-06-01

    A coupled empirical approach to highlight relationships between rainfall, vegetation segmentation, and landslide occurrence is discussed. To reveal such links, two important rainfall events, which occurred over the Esino river basin in central Italy in November 2013 and May 2014, were analysed. The correlation between rainfall and landslides was evaluated by applying an intensity-duration (ID) threshold method, whereas the correlation between vegetation segmentation and landslides was investigated using morphological spatial pattern analysis (MSPA). This coupled approach represents an attempt to find both timing and location of landslide occurrence through an empirical (black box) analysis. Results showed: (i) the ID minimum threshold proposed in a previous study (Gioia et al., 2015) to be verified as an effective equation to assess the rainfall conditions likely to trigger landslides in the study area ("when"), and (ii) the core areas and the fragmented vegetation structures defined by the MSPA to be the most affected by slope failures ("where"). These encouraging findings prompt additional testing and the application of such a coupled empirical approach so that it is possible to achieve an integrated basis for landslide forecasting.

  1. Parascolymia (Scleractinia: Lobophylliidae) in the Central Paratethys Sea (Vienna Basin, Austria) and its possible biogeographic implications.

    Science.gov (United States)

    Reuter, Markus; Wiedl, Thomas; Piller, Werner E

    2015-01-01

    Palaeobiogeographical and palaeodiversity patterns of scleractinian reef corals are generally biased due to uncertain taxonomy and a loss of taxonomic characters through dissolution and recrystallization of the skeletal aragonite in shallow marine limestones. Herein, we describe a fossil lobophylliid coral in mouldic preservation from the early middle Miocene Leitha Limestone of the Central Paratethys Sea (Vienna Basin, Austria). By using grey-scale image inversion and silicone rubber casts for the visualization of the original skeletal anatomy and the detection of distinct micromorphological characters (i.e. shape of septal teeth, granulation of septocostae) Parascolymia bracherti has been identified as a new species in spite of the dissolved skeleton. In the recent era, Parascolymia like all Lobophylliidae is restricted to the Indo-Pacific region, where it is represented by a single species. The new species proves the genus also in the Miocene Mediterranean reef coral province. A review of the spatio-temporal relationships of fossil corals related to Parascolymia indicates that the genus was probably rooted in the Eastern Atlantic‒Western Tethys region during the Paleocene to Eocene and reached the Indo-Pacific region not before the Oligocene. The revealed palaeobiogeographical pattern shows an obvious congruence with that of Acropora and tridacnine bivalves reflecting a gradual equatorwards retreat of the marine biodiversity center parallel to the Cenozoic climate deterioration. PMID:26201071

  2. Digital resource modeling of the northern and central Appalachian Basin coal regions: Top producing coals

    Energy Technology Data Exchange (ETDEWEB)

    Ruppert, L.; Tewalt, S.; Bragg, L.; Wallack, R.; Jenkins, J.; Tully, J. [Geological Survey, Reston, VA (United States)

    1998-12-31

    The US Geological Survey is currently conducting a coal resource assessment of the coal beds and zones that are expected to provide the bulk of the Nation`s coal resources for the next few decades. In partnership with the state geologic surveys of Kentucky, Tennessee, West Virginia, Virginia, Pennsylvania, Ohio, and Maryland, six coal beds will be digitally assessed in the northern and central Appalachian Basin coal region. In ascending stratigraphic order, the beds which range from the Lower Pennsylvanian Pocahontas Formation to the Upper Pennsylvanian Monongahela Group are the Pocahontas No. 3, Pond Creek, Fire Clay, Lower Kittanning, Upper Freeport, and Pittsburgh coals. Comprehensive stratigraphic and geochemical databases have been developed for the coal beds. Maps that show the extent and mined areas of the beds, structure contour, isopach, and overburden thickness have been compiled for the Pittsburgh coal bed and are in preparation for the other coal beds. The resource model for the Pittsburgh coal bed indicates that of the original 33.6 billion short tons (30.5 billion tonnes) of Pittsburgh coal, approximately 15.9 billion short tons (14.4 billion tonnes) remain. The remaining coal is, however, higher in ash and sulfur, and generally thinner and under thicker overburden cover.

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

    Science.gov (United States)

    Hartley, Adrian J.; Evenstar, Laura

    2010-11-01

    Analysis of the Cenozoic stratigraphic development of the forearc of northern Chile between 18°S and 23°30'S, allows constraints to be placed on the timing and nature of basin formation and the uplift history of the Central Andes. Chronostratigraphic charts have been constructed from 20 lithostratigraphic sections distributed throughout the forearc. Sections were taken from the Longitudinal Valley, Central Depression, Calama Basin, Salar de Atacama, Precordillera and the western flank of the Western Cordillera. Correlation and timing of events is largely based on the presence of dated volcanic horizons in all the studied sections. Three chronostratigraphic units are defined based upon the presence of regional unconformities. Deposition of the Late Eocene to Early Miocene chronostratigraphic unit (38-19 Ma) commenced across an irregular unconformity surface between ˜ 38 and 30 Ma with alluvial fan and fluvial sediments derived from the east interbedded with rhyolitic ignimbrites. Aggradation after 25 Ma resulted in development of a large broad basin over much of northern Chile that expanded eastwards through onlap onto basement. Deposition terminated around 19 Ma with the development of an angular unconformity over much, but not all of the study area. During deposition of the Early to Late Miocene chronostratigraphic unit (18-10 Ma) emergent volcanic source areas to the east provided catchments for large fluvial systems that drained westwards into endorheic ephemeral lacustrine basins. Fold growth affected sedimentation restricting accommodation space to small intra-thrust basins in the Precordillera and localised disruption and unconformity development in the Longitudinal Valley. The Late Miocene to present day chronostratigraphic unit (10-0 Ma) followed the development of a regional angular unconformity at 10 Ma. Sedimentation was restricted to a series of thrust-bounded endorheic basins in both the Central Depression and the Precordillera sourced from the east

  4. An integrated framework to assess adaptation options to climate change impacts in an irrigated basin in Central North Chile

    Science.gov (United States)

    Vicuna, S.; Melo, O.; Meza, F. J.; Alvarez, P.; Maureira, F.; Sanchez, A.; Tapia, A.; Cortes, M.; Dale, L. L.

    2013-12-01

    Future climate conditions could potentially affect water supply and demand on water basins throughout the world but especially on snowmelt-driven agriculture oriented basins that can be found throughout central Chile. Increasing temperature and reducing precipitation will affect both the magnitude and timing of water supply this part of the world. Different adaptation strategies could be implemented to reduce the impacts of such scenarios. Some could be incorporated as planned policies decided at the basin or Water Use Organization levels. Examples include changing large scale irrigation infrastructure (reservoirs and main channels) either physically or its operation. Complementing these strategies it is reasonable to think that at a disaggregated level, farmers would also react (adapt) to these new conditions using a mix of options to either modify their patterns of consumption (irrigation efficiency, crop mix, crop area reduction), increase their ability to access new sources of water (groundwater, water markets) or finally compensate their expected losses (insurance). We present a modeling framework developed to represent these issues using as a case study the Limarí basin located in Central Chile. This basin is a renowned example of how the development of reservoirs and irrigation infrastructure can reduce climate vulnerabilities allowing the economic development of a basin. Farmers in this basin tackle climate variability by adopting different strategies that depend first on the reservoir water volume allocation rule, on the type and size of investment they have at their farms and finally their potential access to water markets and other water supplies options. The framework developed can be used to study these strategies under current and future climate scenarios. The cornerstone of the framework is an hydrology and water resources model developed on the WEAP platform. This model is able to reproduce the large scale hydrologic features of the basin such as

  5. 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.

  6. Karyotypic and morphological divergence between two cryptic species of Eigenmannia in the Amazon basin with a new occurrence of XX/XY sex chromosomes (Gymnotiformes: Sternopygidae

    Directory of Open Access Journals (Sweden)

    Danillo S. Silva

    2015-06-01

    Full Text Available Eigenmannia species are widely distributed in the Neotropics, with eight valid species currently recognized. Populations of Eigenmannia from three locations in the eastern Amazon were investigated using cytogenetic and morphological techniques, revealing two taxa designated here as Eigenmannia sp. "A" and Eigenmannia sp. "B". The species differ in three morphometric characters, two meristic characters, and one osteological character. Eigenmannia sp. "A" presents 2n = 34 (22 m/sm+12 st/a and Eigenmannia sp. "B" presents 2n = 38 (14 m/sm+24st/a and simple differentiated sex chromosomes of the type XX/XY. In both species the Constitutive Heterochromatin (CH rich in A-T bases is distributed in the centromeric region of all chromosomes. Eigenmannia sp. "B" also presents CH blocks in the interstitial region of chromosome pairs 8, 9 and X which are positively stained with CMA3, indicating G-C rich regions. The NOR is located on the short arm of chromosome pair 17 of Eigenmannia sp. "A" and on the short arm of pair 14 of Eigenmannia sp. "B". FISH with rDNA probes hybridized to different-sized regions between homologs, suggesting heteromorphism. The differentiation of the X chromosome in Eigenmannia sp. "B" could be the result of amplification of repetitive DNA sequences.

  7. Managing drought risk with a computer model of the Raritan River Basin water-supply system in central New Jersey

    Science.gov (United States)

    Dunne, Paul; Tasker, Gary

    1996-01-01

    The reservoirs and pumping stations that comprise the Raritan River Basin water-supply system and its interconnections to the Delaware-Raritan Canal water-supply system, operated by the New Jersey Water Supply Authority (NJWSA), provide potable water to central New Jersey communities. The water reserve of this combined system can easily be depleted by an extended period of below-normal precipitation. Efficient operation of the combined system is vital to meeting the water-supply needs of central New Jersey. In an effort to improve the efficiency of the system operation, the U.S. Geological Survey (USGS), in cooperation with the NJWSA, has developed a computer model that provides a technical basis for evaluating the effects of alternative patterns of operation of the Raritan River Basin water-supply system. This fact sheet describes the model, its technical basis, and its operation.

  8. Suspected Lead Poisoning in an Amazon Parrot

    OpenAIRE

    McDonald, Lawrence J.

    1986-01-01

    A double yellow headed Amazon parrot (Amazona ochrocephala tresmariae) of unknown age and sex was examined for an acute onset of anorexia, listlessness, central nervous system signs and diarrhea. A tentative diagnosis of lead toxicosis was achieved based on radiographs, clinical pathology and response to therapy. Chelation therapy (Calcium EDTA) and supportive measures resulted in an uneventful recovery.

  9. Tectono-sedimentary evolution of the Tertiary Piedmont Basin (NW Italy) within the Oligo-Miocene central Mediterranean geodynamics

    Science.gov (United States)

    Maino, Matteo; Decarlis, Alessandro; Felletti, Fabrizio; Seno, Silvio

    2013-06-01

    analyze the tectono-sedimentary and thermochronometric constraints of the Tertiary Piedmont Basin (TPB) and its adjoining orogen, the Ligurian Alps, providing new insights on the basin evolution in response to a changing geodynamic setting. The geometry of the post-metamorphic faults of the Ligurian belt as well as the fault network that controlled the Oligo-Miocene TPB deposition has been characterized through a detailed structural analysis. Three main faulting stages have been distinguished and dated thanks to the relationships among faults and basin stratigraphy and thermochronometric data. The first stage (F1, Rupelian-Early Chattian) is related to the development of extensional NNW-directed faults, which controlled the exhumation of the orogen and the deposition of nearshore clastics. During the Late Chattian, the basin drowning is marked by mudstones and turbidites, which deposition was influenced by the second faulting stage (F2). This phase was mainly characterized by NE- to ENE-striking faults developed within a transtensional zone. Since the Miocene, the whole area was dominated by transpressive tectonics. The sedimentation was represented by a condensed succession followed by a very thick, turbiditic complex. At the regional scale, this succession of events reflects the major geodynamic reorganization in the central Mediterranean region during the Oligo-Miocene times, induced by the late-collisional processes of the Alps, by the eastward migration of the Apennines subduction and by the opening of extensional basins (i. e., the Liguro-Provençal Ocean).

  10. Quantitative and qualitative vulnerability of the Makutupora basin aquifer Dodoma, central Tanzania

    International Nuclear Information System (INIS)

    The rapid development of Dodoma town has raised demand for water for domestic, irrigation and industrial use. Uncontrolled human activities pose threat of contamination of the well field and damage to recharge areas of Makutupora basin. Monitoring data collected over the years indicate that the basin is overpumped in dry years and that peripheral boreholes register high nitrate levels from nearby settlements and intensive use of agrochemicals on farms within the basin

  11. A note on chemical composition and origin of ferromanganese oxide coated and uncoated pumice samples from central Indian Ocean basin

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N.; Parthiban, G.; Moraes, C.; Rajalakshmi, R.; Lekshmi, S.; Athira, S.; JaiSankar, S.

    the physical properties of pumice such as density, specific gravity, porosity, void ratio and degree of saturation. Detailed studies related to chemical composition of both coated and uncoated pumice from CIOB are rare (Pattan et al, 2008). The objective..., N. G., IYER, S. D. and ILANGOVAN, D. (2011) Physical properties, morphology and petrological characteristics of pumices from the Central Indian Ocean Basin. Acta Geologica Sinica., v. 85, pp. 826-839. KAY, S. M. (2001) Tertiary to Recent...

  12. Paleomagnetism of the Plio-Pleistocene continental sediments from the north -eastern edge of the Fucino basin (Central Italy)

    OpenAIRE

    F. Galadini; L. Sagnotti; L. Alfonsi

    1995-01-01

    The paleomagnetism of the Plio-Pleistocene continental sediments cropping out at the north-eastern edge of the Fucino extensionaI basin (Italy, Central Apennines) was investigated. The area is characterized by strong neo-tectonic activity and the original purpose was to investigate possibIe verticaI axis rotations in Plio-Pleisto- cene sediments, in order to improve the understanding of the recent geodynamic processes. Scarcity of suit- able outcrops limited sampling at 8 sites (83 specimens)...

  13. A coupled empirical approach for rainfall and land use correlation to landslide occurrence in the Esino river basin, central Italy

    OpenAIRE

    E. Gioia; T. Carone; F. Marincioni

    2015-01-01

    A coupled empirical approach for studying possible correlations among rainfall, vegetation segmentation and landslide occurrence is discussed. To reveal such links two important rainfall events, occurred over the Esino river basin in central Italy, in November 2013 and May 2014, were analysed. The correlation between rainfall and landslides was carried out applying an intensity–duration (ID) threshold method, whereas the correlation between vegetation segmen...

  14. Imaging of the seismogenic source fault in the fold-and-thrust belt, Niigata basin, central Japan

    Science.gov (United States)

    Kato, N.; Sato, H.; Abe, S.; Kawai, N.; Saito, H.; Iwasaki, T.; Shiraishi, K.; Ishiyama, T.; Inaba, M.

    2010-12-01

    Associated with the opening of the Japan Sea, volcanic rift-basins have been developed along the Japan Sea coast of northern Honshu. The Niigata basin, central Japan, is one of such basins and filled by thick (faulting. Due to thick Neogene sediments, relationship between active faults/folds at near the surface and deep-sited seismogenic source faults is poorly understood. To reveal the crustal structure, in particular geometry of source faults, onshore-offshore integrated deep seismic profiling was undertaken along the three seismic lines in 2008, 2009 and 2010. The 2009 Aizu-Sado Seismic line is a 135-km-long, onshore-offshore seismic line across Niigata basin and Sado island, which is located in the eastern part of Japan Sea. The 2008 Sanjo-Yahiko Seismic line is located 20 km south of the seismic line and trending parallel to it. The 2010 Higashiyama-Mishima seismic line cut through the northern part of the epicentral area of the 2007 Chuetsu-oki earthquake. The seismic sources were air-gun (3020 cu. inch), four vibroseis trucks and explosives (cables, cable-connected-recording system and offline recorders, forming a maximum 2400 channels receiver array. The basin fill consists of early to middle Miocene volcaniclastic rocks and overlying Neogene sedimentary rocks showing upward coarsening facies deposited under bathyal to fluvial environment. Main features of basin development, such as early Miocene normal faulting, associated with the formation of Japan Sea, and shortening deformation since the Pliocene, are well demonstrated on the seismic sections. Particularly, boundary between pre-Tertiary meta-sedimentary rocks and Miocene felsic volcanics were identified by velocity profiles deduced by diving wave tomography and they enabled us to identify the geometry of extensional rift-basin. Fault reactivation of Miocene normal faulting to subsequent reverse faulting is common style of deformation. The fault reactivation processes of the eastern boundary fault of

  15. Statistical prediction of seasonal discharge in the Naryn basin for water resources planning in Central Asia

    Science.gov (United States)

    Apel, Heiko; Gafurov, Abror; Gerlitz, Lars; Unger-Shayesteh, Katy; Vorogushyn, Sergiy; Merkushkin, Aleksandr; Merz, Bruno

    2016-04-01

    The semi-arid regions of Central Asia crucially depend on the water resources supplied by the mountainous areas of the Tien-Shan and Pamirs. During the summer months the snow and glacier melt water of the rivers originating in the mountains provides the only water resource available for agricultural production but also for water collection in reservoirs for energy production in winter months. Thus a reliable seasonal forecast of the water resources is crucial for a sustainable management and planning of water resources.. In fact, seasonal forecasts are mandatory tasks of national hydro-meteorological services in the region. Thus this study aims at a statistical forecast of the seasonal water availability, whereas the focus is put on the usage of freely available data in order to facilitate an operational use without data access limitations. The study takes the Naryn basin as a test case, at which outlet the Toktogul reservoir stores the discharge of the Naryn River. As most of the water originates form snow and glacier melt, a statistical forecast model should use data sets that can serve as proxy data for the snow masses and snow water equivalent in late spring, which essentially determines the bulk of the seasonal discharge. CRU climate data describing the precipitation and temperature in the basin during winter and spring was used as base information, which was complemented by MODIS snow cover data processed through ModSnow tool, discharge during the spring and also GRACE gravimetry anomalies. For the construction of linear forecast models monthly as well as multi-monthly means over the period January to April were used to predict the seasonal mean discharge of May-September at the station Uchterek. An automatic model selection was performed in multiple steps, whereas the best models were selected according to several performance measures and their robustness in a leave-one-out cross validation. It could be shown that the seasonal discharge can be predicted with

  16. Two-stage formation model of the Junggar basin basement: Constraints to the growth style of Central Asian Orogenic Belt

    Science.gov (United States)

    He, Dengfa

    2016-04-01

    Junggar Basin is located in the central part of the Central Asian Orogenic Belt (CAOB). Its basement nature is a highly controversial scientific topic, involving the basic style and processes of crustal growth. Some researchers considered the basement of the Junggar Basin as a Precambrian continental crust, which is not consistent with the petrological compositions of the adjacent orogenic belts and the crust isotopic compositions revealed by the volcanic rocks in the basin. Others, on the contrary, proposed an oceanic crust basement model that does not match with the crustal thickness and geophysical characteristics of the Junggar area. Additionally, there are several viewponits, such as the duplex basement with the underlying Precambrian crystalline rocks and the overlying pre-Carboniferous folded basement, and the collaged basement by the Precambrian micro-continent block in the central part and the Hercynian accretionary folded belts circling it. Anyway, it is necessary to explain the property of basement rock, its strong inhomogeneous compositions as well as the geophysical features. In this paper, based on the borehole data from more than 300 industry wells drilled into the Carboniferous System, together with the high-resolution gravity and magnetic data (in a scale of 1:50,000), we made a detailed analysis of the basement structure, formation timing and processes and its later evolution on a basis of core geochemical and isotopic analysis. Firstly, we defined the Mahu Pre-Cambrian micro-continental block in the juvenile crust of Junggar Basin according to the Hf isotopic analysis of the Carboniferous volcanic rocks. Secondly, the results of the tectonic setting and basin analysis suggest that the Junggar area incorporates three approximately E-W trending island arc belts (from north to south: Yemaquan- Wulungu-Chingiz, Jiangjunmiao-Luliang-Darbut and Zhongguai-Mosuowan- Baijiahai-Qitai island arcs respectively) and intervened three approximately E-W trending

  17. Relationship between chemical composition and magnetic susceptibility in sediment cores from Central Indian Ocean Basin

    Indian Academy of Sciences (India)

    J N Pattan; G Parthiban; V K Banakar; A Tomer; M Kulkarni

    2008-04-01

    Three sediment cores in a north–south transect (3°N to 13°S) from different sediment types of the Central Indian Ocean Basin (CIOB) are studied to understand the possible relationship between magnetic susceptibility () and Al, Fe, Ti and Mn concentrations. The calcareous ooze core exhibit lowest (12.32 × 10-7m3 kg−1), Al (2.84%), Fe (1.63%) and Ti (0.14%), terrigenous clay core with moderate (29.9 × 10-7 m3 kg−1) but highest Al (6.84%), Fe (5.20%) and Ti (0.44%), and siliceous ooze core with highest (38.06 × 10-7 m3 kg−1) but moderate Al (4.49%), Fe (2.80%) and Ti (0.19%) contents. The distribution of and detrital proxy elements (Al, Fe, and Ti) are identical in both calcareous and siliceous ooze. Interestingly, in terrigenous core, the behaviour of is identical to only Ti content but not with Al and Fe suggesting possibility of Al and Fe having a non-detrital source. The occurrence of phillipsite in terrigenous clay is evident by the Al-K scatter plot where trend line intersects K axis at more than 50% of total K suggesting excess K in the form of phillipsite. Therefore, the presence of phillipsite might be responsible for negative correlation between and Al ( = −0.52). In siliceous ooze the strong positive correlations among , Alexc and Feexc suggest the presence of authigenic Fe-rich smectite. High Mn content (0.5%) probably in the form of manganese micronodules is also contributing to in both calcareous and siliceous ooze but not in the terrigenous core where mean Mn content (0.1%) is similar to crustal abundance. Thus, systematically records the terrigenous variation in both the biogenic sediments but in terrigenous clay it indirectly suggests the presence of authigenic minerals.

  18. A LEPS approach to the predictability of intense rain storms in the Central Mediterranean basin

    Directory of Open Access Journals (Sweden)

    S. Federico

    2008-04-01

    Full Text Available This study investigates a method for best member selection of a Limited area model Ensemble Prediction System (LEPS with the goal to increase quantitative precipitation forecast. A case study that occurred between 22-24 May 2002 over Calabria, southern Italy, is discussed.

    Mediterranean storms often develop under upper level disturbances which are usually associated with high values of potential vorticity. Anomalously high values of potential vorticity can be identified by the METEOSAT water vapor channel centered around 6.3 μm because they are associated with dark band on the METEOSAT image. This signature offers a chance to identify the upper level disturbance that can be exploited in data void countries as Calabria.

    The working hypothesis is that the uncertainty in the representation of the upper-level disturbance has a major impact on the precipitation forecast. This issue is utilized in an ensemble forecast where member forecasts are compatible with the analysis and forecast errors. These members are grouped in five clusters by a hierarchical clustering technique which utilizes the height of the dynamical tropopause to compute distances between members. Therefore the members of a cluster have a similar representation of the upper level disturbance. For each cluster a representative member is selected and its pseudo water vapor image is compared with the corresponding METEOSAT 7 water vapor image at a specific time, antecedent to the rain occurrence over Calabria. The subjective evaluation of the comparison allows to gain physical insight in the storm evolution and to select representative members which are more in agreement with the METEOSAT image.

    Results, even if for a case study, show the feasibility of the methodology that, if confirmed by further investigations, could be valuable in data void countries as the central Mediterranean basin.

  19. Geothermal energy from deep sedimentary basins: The Valley of Mexico (Central Mexico)

    Science.gov (United States)

    Lenhardt, Nils; Götz, Annette E.

    2015-04-01

    The geothermal potential of the Valley of Mexico has not been addressed in the past, although volcaniclastic settings in other parts of the world contain promising target reservoir formations. A first assessment of the geothermal potential of the Valley of Mexico is based on thermophysical data gained from outcrop analogues, covering all lithofacies types, and evaluation of groundwater temperature and heat flow values from literature. Furthermore, the volumetric approach of Muffler and Cataldi (1978) leads to a first estimation of ca. 4000 TWh (14.4 EJ) of power generation from Neogene volcanic rocks within the Valley of Mexico. Comparison with data from other sedimentary basins where deep geothermal reservoirs are identified shows the high potential of the Valley of Mexico for future geothermal reservoir utilization. The mainly low permeable lithotypes may be operated as stimulated systems, depending on the fracture porosity in the deeper subsurface. In some areas also auto-convective thermal water circulation might be expected and direct heat use without artificial stimulation becomes reasonable. Thermophysical properties of tuffs and siliciclastic rocks qualify them as promising target horizons (Lenhardt and Götz, 2015). The here presented data serve to identify exploration areas and are valuable attributes for reservoir modelling, contributing to (1) a reliable reservoir prognosis, (2) the decision of potential reservoir stimulation, and (3) the planning of long-term efficient reservoir utilization. References Lenhardt, N., Götz, A.E., 2015. Geothermal reservoir potential of volcaniclastic settings: The Valley of Mexico, Central Mexico. Renewable Energy. [in press] Muffler, P., Cataldi, R., 1978. Methods for regional assessment of geothermal resources. Geothermics, 7, 53-89.

  20. Multiple ash layers in late Quaternary sediments from the Central Indian Basin

    Science.gov (United States)

    Mascarenhas-Pereira, M. B. L.; Nagender Nath, B.; Iyer, S. D.; Borole, D. V.; Parthiban, G.; Jijin, R.; Khedekar, V.

    2016-04-01

    We have investigated three sediment cores collected from water depths > 5000 m along the transect 76°30‧E in close proximity to a fracture zone in the Central Indian Basin (CIB). The cores yielded five volcanic horizons of which four have visual and dispersed shards. Rhyolitic glass shards of bubble wall, platy, angular and blocky types were retrieved from various stratigraphic horizons in the cores. The abundance of glass shards, composition of bulk sediments, and 230Thexcess ages of the host sediments were used to distinguish the volcanic horizons. Of the four volcanic horizons, three are now newly reported and correspond to ages of ~ 85, 107-109 and 142-146 ka while the fourth horizon is of 70-75 ka. By using trace element ratios and Cr and Nb-based normative calculations, cryptotephra has been identified for the first time from the CIB sediment. The cryptotephra forms the fifth ash horizon and is of ~ 34 ka. A comparison with the published data on volcanic tephra in and around the Indian Ocean indicate the shard rich horizon (SRH) of 70-75 ka to resemble the Younger Toba Tuffs (YTT), while the other volcanic horizons that were deposited during different time periods do not correlate with any known marine or terrestrial records. These tephra layers have produced a tephrostratigraphic framework across the tectonically and volcanically complex regions of the CIB. Due to the lack of terrestrial equivalents of these tephra, it is hypothesized that the newly found volcanic horizons may have been derived from submarine volcanic eruptions. Multiple layers of submarine volcaniclastic deposits found at water depths as great as 5300 m reaffirm the growing belief that submarine phreatomagmatic eruptions are much more common in the intraplate region of the Indian Ocean than previously reported.

  1. Mercury and flooding cycles in the Tapajos river basin, Brazilian Amazon: The role of periphyton of a floating macrophyte (Paspalum repens)

    International Nuclear Information System (INIS)

    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, δ13C, δ15N and bacterial heterotrophic production as 3H-leucine incorporation rate. THg concentration varied from 67 to 198 ng/g and the potential of Me203Hg 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 Me203Hg 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 δ13C. The discriminant analysis showed a significant difference in periphyton δ15N, δ13C and THg between seasons, where the rainy season presented higher δ15N and the wet period lighter δ13C, lower THg values and higher Me203Hg formation. This exploratory study indicates that the flooding cycle could influence the periphyton composition, mercury accumulation and methylmercury production. - Research highlights: → During rainy season mercury (Hg2+) is carried out from terrestrial to aquatic systems by runoff. → Macrophyte roots accumulates Hg2+ from suspended particulate matter (SPM). → Hg methylation increases during the wet season. → Flooded forest is a source of labile organic carbon and bioavailable Hg. → Macrophytes decompose during the dry season and made up terrestrial soil.

  2. Marine Ingressive Events Recorded in Epicontinental Sequences:Example from the Cretaceous Songliao Basin of NE China in Comparison with the Triassic Central Europe Basin of SW Germany

    Institute of Scientific and Technical Information of China (English)

    WANG Pujun; LIU Wanzhu; YIN Xiuzhen; SCHNEIDER Werner; MATTERN Frank

    2002-01-01

    Songliao Basin is filled predominantly with continental facies sediments including alluvial fan, fluvial plain, fan delta, lacustrine delta, shore - shallow lacustrine, beach salty flat, semi - deep to deep lacustrine, subaqueous gravity flow,lacustrine swamp and pyroclastic sediments. However, some event units were formed during lake - marine linking periods of the Mid - Cretaceous in the basin, which include black shales with high values for salinity (Sr/Ba) , alkalinity ( Ca + Mg)/(Si + Al) , reducibility (Ni + Zn)/Ga and sulfide sulfur as well as heavy isotopes. The Breitenholz -section to be represented for facies comparison with the Cretaceous evaporitic series in Northeast China is localized in Southwest Germany. Stratigraphically it belongs to the Crabfeld Formation of Keuper of the Germanic Triassic corresponding to Ladinian - Carnian of the international reference scale, and is generally called Lower Gipskeuper. The Germanic Triassic was deposited in the epicontinental (cratonic) central Europe Basin. It covered the area in between Great Britain, North Sea, Poland and Southern Germany. It is composed of cyclic deposits of multicolored mudstones, gypsum/anhydrite, and dolomite beds. The two cases of marine ingression - influenced sequences share some common features.

  3. Suspended-sediment transport in the Big Eau Pleine River Basin, central Wisconsin

    Science.gov (United States)

    Hindall, S.M.

    1978-01-01

    Suspended-sediment yields in the Big Eau Pleine River basin are low to moderate in comparison with other drainage basins in Wisconsin. Average annual yield in the Big Eau Pleine River near Stratford is 32.tons per square mile, with an annual yield ranging from 1.0 to 64 tons per square mile. Fenwood Creek at Bradley and Freeman Creek at Halder, two smaller tributary basins, have average annual yields of 3.3 and 7.9 tons per square mile, respectively. Suspended-sediment concentrations in the basin ranged from 0 to 960 milligrams per liter, with a median concentration at the Stratford site of 13 milligrams per liter. Ninety percent of the material transported by the streams of the Big Eau Pleine basin is finer than sand and is made up of about equal percentages of silt and clay.

  4. Geochemical fractionation of Ni, Cu and Pb in the deep sea sediments from the Central Indian Ocean Basin: An insight into the mechanism of metal enrichment in sediment

    Digital Repository Service at National Institute of Oceanography (India)

    Sensarma, S.; Chakraborty, P.; Banerjee, R.; Mukhopadhyay, S.

    Metal speciation study in combination with major element chemistry of deep sea sediments provided possible metal enrichment pathways in sediments collected from environmentally different locations of Central Indian Ocean Basin (CIB). Metal...

  5. Relationship between size and geochemistry of polymetallic nodules from the Central Indian Ocean Basin: Significance in selection of high grade nodules

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.; Ambre, N.V.

    Morphological, mineralogical and geochemical studies on nodules of different sizes collected from the Central Indian Ocean Basin (CIOB) show two suits of nodule formation by oxic diagenetic and hydrogenous process resulting into distinct properties...

  6. Understanding volcanism at the PETM: Abundant volcanic ash layers in the Central Tertiary Basin of Spitsbergen, Svalbard

    Science.gov (United States)

    Jones, Morgan; Eliassen, Gauti; Svensen, Henrik; Jochmann, Malte; Friis, Bjarki; Jerram, Dougal; Planke, Sverre

    2014-05-01

    During the early Tertiary, Svalbard developed a fold-thrust belt on its western margin with an associated foreland basin in the central-south of what is now Spitsbergen. This Central Tertiary Basin (CTB) is a syn-orogenic sedimentary basin in a strike-slip regime. The CTB contains the ~1900 m thick Van Mijenfjorden group, a dominantly sandstone-shale succession that was deposited in a North-South extending basin. Sediments in this group display evidence of major transgressive-regressive cycles related to local tectonics and eustatic sea level change. This basin is ideal for study as it has been extensively cored for coal prospecting, allowing a suite of sedimentary logs across the basin to be considered. Prominent marker beds in this sedimentary sequence are 1-30 cm thick bentonites, formed from the chemical weathering of volcanic tuff deposits. In this study, we focus on 8 sedimentary logs across the CTB, spanning the Palaeocene to lower Eocene in age. Bentonites are common in the Palaeocene cores (Basilika and Grumantbyen formations), while rarer but still occasionally present in the Eocene Frysjaodden formation. The cores had between 3-12 observable bentonite layers that showed large variations in preservation and subsequent reworking. Roots and other finer organic material were common, especially when the bentonites were found next to coal seams. Geochemical affinities between ash layers were investigated to identify basin-wide depositional events, with the aim of elucidating the provenance of these ashes. This sedimentary sequence is of broader interest as it covers the Palaeocene-Eocene thermal maximum (PETM), an extreme global warming event driven by large releases to the atmosphere of CO2 and/or CH4, evidenced by a negative carbon isotope excursion in both the ocean and atmosphere. Potential sources include volcanism and associated gas release from intruded sediments, CH4 hydrate dissociation, and/or the oxidation of organic matter. These formations are

  7. Rock-Eval pyrolysis and vitrinite reflectance results from the Sheep Creek 1 well, Susitna basin, south-central Alaska

    Science.gov (United States)

    Stanley, Richard G.; Lillis, Paul G.; Pawlewicz, Mark J.; Haeussler, Peter J.

    2014-01-01

    We used Rock-Eval pyrolysis and vitrinite reflectance to examine the petroleum source potential of rock samples from the Sheep Creek 1 well in the Susitna basin of south-central Alaska. The results show that Miocene nonmarine coal, carbonaceous shale, and mudstone are potential sources of hydrocarbons and are thermally immature with respect to the oil window. In the samples that we studied, coals are more organic-rich and more oil-prone than carbonaceous shales and silty mudstones, which appear to be potential sources of natural gas. Lithologically similar rocks may be present in the deeper parts of the subsurface Susitna basin located west of the Sheep Creek 1 well, where they may have been buried deeply enough to generate oil and (or) gas. The Susitna basin is sparsely drilled and mostly unexplored, and no commercial production of hydrocarbons has been obtained. However, the existence of potential source rocks of oil and gas, as shown by our Rock-Eval results, suggests that undiscovered petroleum accumulations may be present in the Susitna basin.

  8. Hydrogeology and hydrogeochemistry at a site of strategic importance: the Pareja Limno-reservoir drainage basin (Guadalajara, central Spain)

    Science.gov (United States)

    Molina-Navarro, Eugenio; Sastre-Merlín, Antonio; Vicente, Rosa; Martínez-Pérez, Silvia

    2014-08-01

    A small calcareous basin in central Spain was studied to establish the role of groundwater in the Pareja Limno-reservoir. Limno-reservoirs aim to preserve a constant water level in the riverine zone of large reservoirs to mitigate the impacts arising from their construction. Groundwater flow contribution (mean 60 %) was derived by recharge estimation. In situ measurements (spring discharge, electrical conductivity and sulfate) were undertaken and spring discharge was compared with a drought index. Twenty-eight springs were monitored and three hydrogeological units (HGUs) were defined: a carbonate plateau (HGU1), the underlying aquitard (HGU2), and the gypsum-enriched HGU3. HGU1 is the main aquifer and may play a role in the preservation of the limno-reservoir water level. Hydrogeochemical sampling was conducted and the code PHREEQC used to describe the main geochemical processes. Weathering and dissolution of calcite and gypsum seem to control the hydrogeochemical processes in the basin. Water progresses from Ca2+-HCO3 - in the upper basin to Ca2+-SO4 2- in the lower basin, where HGU3 outcrops. A clear temporal pattern was observed in the limno-reservoir, with salinity decreasing in winter and increasing in summer. This variation was wider at the river outlet, but the mixing of the river discharge with limno-reservoir water buffered it.

  9. Paleomagnetic and Anisotropy of Magnetic Susceptibility (AMS analyses of the Plio-Pleistocene extensional Todi basin, Central Italy

    Directory of Open Access Journals (Sweden)

    L. Alfonsi

    1997-06-01

    Full Text Available In the last few years paleomagnetic investigations within the Apennine chain have revealed that the area is characterized by a complex pattern of deformation, not linkable to a simple and homogeneous process. In order to estimate the amount, sense and timing of vertical axis rotations within the Central Apennines, Neogene continental basins have been investigated for paleomagnetic studies. The paleomagnetic results obtained in the Plio-Pleistocene Todi basin showed that the Upper Pliocene-Lower Pleistocene evolution, associated with major dip-slip tectonics, has not involved vertical axis rotation since that time. The Anisotropy of Magnetic Susceptibility analysis (AMS, carried out on the same samples treated for paleomagnetic determination, revealed the presence of two groups of specimens characterized by different magnetic lineation directions. One direction trends NE-SW and is parallel to the orientation of the regional extension stress typical of the area. This direction is observed throughout the northern basin. The other, restricted to the southern basin, trends N-S and shows no links with the tectonic, hydrological-sedimentary conditions of the area. The results of the AMS analysis will be presented and discussed in the light of the rock magnetic results and the tectonic framework of the area.

  10. Constraints on the development of Proterozoic basins in central India from 40Ar/39Ar analysis of authigenic glauconitic minerals

    Science.gov (United States)

    Conrad, J.E.; Hein, J.R.; Chaudhuri, A.K.; Patranabis-Deb, S.; Mukhopadhyay, J.; Deb, G.K.; Beukes, N.J.

    2011-01-01

    Ages of some key stratigraphic sequences in central Indian Proterozoic basins are based predominantly on lithostratigraphic relationships that have been constrained by only a few radioisotopic dates. To help improve age constraints, single grains of glauconitic minerals taken from sandstone and limestone in two Proterozoic sequences in the Pranhita-Godavari Valley and the Chattisgarh basin were analyzed by the 40Ar/39Ar incremental heating method. Analysis of the age spectra distinguishes between ages that are interpreted to reflect the time of glauconite formation, and anomalous ages that result from inherited argon or postcrystallization heating. The analyses indicate an age of 1686 ± 6 Ma for the Pandikunta Limestone and 1566 ± 6 Ma for the Ramgundam Sandstone, two units in the western belt of Proterozoic sequences in Pranhita-Godavari Valley. Glauconite from the Chanda Limestone, in the upper part of this sequence, contains inherited 40Ar but is interpreted to reflect an age of ca. 1200 Ma. Glauconite from the Somanpalli Group in the eastern belt of the Pranhita-Godavari Valley gives an age of 1620 ± 6 Ma. In the Chattisgarh basin, glauconite from two units gives disturbed ages that suggest a period of regional heating in the Chattisgarh basin at ca. 960–1000 Ma. These new ages indicate that these sequences are 200–400 m.y. older than previously recognized, which has important implications for geochemical studies of Mesoproterozoic ocean redox conditions in addition to providing important constraints on regional tectonics and lithostratigraphy.

  11. Amazon River carbon dioxide outgassing fuelled by wetlands

    Science.gov (United States)

    Abril, Gwenaël; Martinez, Jean-Michel; Artigas, L. Felipe; Moreira-Turcq, Patricia; Benedetti, Marc F.; Vidal, Luciana; Meziane, Tarik; Kim, Jung-Hyun; Bernardes, Marcelo C.; Savoye, Nicolas; Deborde, Jonathan; Souza, Edivaldo Lima; Albéric, Patrick; Landim de Souza, Marcelo F.; Roland, Fabio

    2014-01-01

    River systems connect the terrestrial biosphere, the atmosphere and the ocean in the global carbon cycle. A recent estimate suggests that up to 3 petagrams of carbon per year could be emitted as carbon dioxide (CO2) from global inland waters, offsetting the carbon uptake by terrestrial ecosystems. It is generally assumed that inland waters emit carbon that has been previously fixed upstream by land plant photosynthesis, then transferred to soils, and subsequently transported downstream in run-off. But at the scale of entire drainage basins, the lateral carbon fluxes carried by small rivers upstream do not account for all of the CO2 emitted from inundated areas downstream. Three-quarters of the world's flooded land consists of temporary wetlands, but the contribution of these productive ecosystems to the inland water carbon budget has been largely overlooked. Here we show that wetlands pump large amounts of atmospheric CO2 into river waters in the floodplains of the central Amazon. Flooded forests and floating vegetation export large amounts of carbon to river waters and the dissolved CO2 can be transported dozens to hundreds of kilometres downstream before being emitted. We estimate that Amazonian wetlands export half of their gross primary production to river waters as dissolved CO2 and organic carbon, compared with only a few per cent of gross primary production exported in upland (not flooded) ecosystems. Moreover, we suggest that wetland carbon export is potentially large enough to account for at least the 0.21 petagrams of carbon emitted per year as CO2 from the central Amazon River and its floodplains. Global carbon budgets should explicitly address temporary or vegetated flooded areas, because these ecosystems combine high aerial primary production with large, fast carbon export, potentially supporting a substantial fraction of CO2 evasion from inland waters.

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

    Science.gov (United States)

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

    2015-12-01

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

  13. The Wavelet ToolKat: A set of tools for the analysis of series through wavelet transforms. Application to the channel curvature and the slope control of three free meandering rivers in the Amazon basin.

    Science.gov (United States)

    Vaudor, Lise; Piegay, Herve; Wawrzyniak, Vincent; Spitoni, Marie

    2016-04-01

    The form and functioning of a geomorphic system result from processes operating at various spatial and temporal scales. Longitudinal channel characteristics thus exhibit complex patterns which vary according to the scale of study, might be periodic or segmented, and are generally blurred by noise. Describing the intricate, multiscale structure of such signals, and identifying at which scales the patterns are dominant and over which sub-reach, could help determine at which scales they should be investigated, and provide insights into the main controlling factors. Wavelet transforms aim at describing data at multiple scales (either in time or space), and are now exploited in geophysics for the analysis of nonstationary series of data. They provide a consistent, non-arbitrary, and multiscale description of a signal's variations and help explore potential causalities. Nevertheless, their use in fluvial geomorphology, notably to study longitudinal patterns, is hindered by a lack of user-friendly tools to help understand, implement, and interpret them. We have developed a free application, The Wavelet ToolKat, designed to facilitate the use of wavelet transforms on temporal or spatial series. We illustrate its usefulness describing longitudinal channel curvature and slope of three freely meandering rivers in the Amazon basin (the Purus, Juruá and Madre de Dios rivers), using topographic data generated from NASA's Shuttle Radar Topography Mission (SRTM) in 2000. Three types of wavelet transforms are used, with different purposes. Continuous Wavelet Transforms are used to identify in a non-arbitrary way the dominant scales and locations at which channel curvature and slope vary. Cross-wavelet transforms, and wavelet coherence and phase are used to identify scales and locations exhibiting significant channel curvature and slope co-variations. Maximal Overlap Discrete Wavelet Transforms decompose data into their variations at a series of scales and are used to provide

  14. Ocorrência do molusco asiático Corbicula fluminea (Müller, 1774 (Bivalvia, Corbiculidae no baixo rio Negro, Amazônia central Occurrence of the Asian mollusc Corbicula fluminea (Müller, 1774 (Bivalvia, Corbiculidae in the lower Rio Negro, Central Amazon Region, Brazil

    Directory of Open Access Journals (Sweden)

    Daniel Mansur Pimpão

    2008-01-01

    Full Text Available O rio Negro é um dos maiores afluentes do rio Amazonas, mas poucos moluscos foram registrados até o momento para aquele rio, representados apenas por gastrópodes. Foi registrada a presença do molusco bivalve exótico Corbicula fluminea na margem esquerda do baixo rio Negro, no lago do Tupé e no Catalão - margem direita do rio Negro, todas localidades no município de Manaus, Brasil. O registro foi realizado por meio da coleta de conchas e espécimes vivos. É o primeiro registro de C. fluminea para o estado do Amazonas e Amazônia central.The Rio Negro is one of the biggest Rio Amazonas tributaries. Few molluscs have been registered to that river yet, represented only by gastropods. It is reported the occurrence of the exotic bivalve mollusc Corbicula fluminea in left bank margin of Rio Negro, Lago do Tupé and Catalão - right bank margin of Rio Negro, all localities in the municipality of Manaus, Brazil. The species is recorded by a collection of shells and specimens alive. This is the first occurrence of C. fluminea in the Amazon State and Central Amazon.

  15. 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

  16. 3D seismic geomorphology of mass transport complexes in a foredeep basin: Examples from the Pleistocene of the Central Adriatic Basin (Mediterranean Sea)

    Science.gov (United States)

    Dalla Valle, Giacomo; Gamberi, Fabiano; Rocchini, Patrizia; Minisini, Daniel; Errera, Alessia; Baglioni, Luca; Trincardi, Fabio

    2013-08-01

    Three-dimensional (3D) seismic-reflection data has shed light on the character of a series of mass transport complexes (MTCs) emplaced during the Pleistocene in the Pescara Basin (Central Adriatic Sea, Italy). The Pescara Basin is the Plio-Pleistocene inner foredeep of the Central Apennines orogen, which was filled by a rapidly prograding, margin-scale clinoforms system. Three MTCs punctuate the normal turbiditic and hemipelagic sedimentary succession of the Pescara Basin foredeep. MTC_0 is the oldest one and covers an area of around 74 km2. It is composed of three different mass transport deposits (MTDs) resulting from individual collapses that involved a shelf-edge delta during a period of relative sea level rise. MTC_1, the intermediate age MTC, is the largest one, with an area of 90 km2. It has a 10 km wide cookie-bite headwall region that indents the upper slope and, in places, reaches the continental shelf-break. MTC_1 is made up of four laterally and vertically stacked MTDs which are the result of a composite set of failures that migrated progressively upslope in a sedimentary setting dominated by contourite deposits. MTC_2 is the youngest and the smallest one, with an area of 55 km2. It has a 5 km long headwall confined in correspondence with a sedimentary bulge developed in the upper slope. Its geomorphic setting leads us to consider two different episodes of failure rooted at different depths. The investigation of the MTCs, through the coupling of 3D seismic geomorphology, seismic facies analysis and rollover trajectory analysis, reveals that the type of sedimentary environment, the rate of sediment accumulation, the source region and the depth of rooting of the failure, are the major controlling factors on MTC evolution and emplacement. Each MTC of the Pescara Basin foredeep is generally confined within a discrete clinotheme. Finally, the rollover trajectory analysis has shown that, in the PB foredeep, a sediment failure can possibly occur at any

  17. Molecular composition of organic aerosols in central Amazonia: an ultra-high resolution mass spectrometry study

    OpenAIRE

    I. Kourtchev; R. H. M. Godoi; Connors, S.; Levine, J. G.; Archibald, A.; Godoi, A.F.L.; Paralovo, S.; C. G. G. Barbosa; R. A. F. Souza; Manzi, A. O.; Seco, R.; Sjostedt, S.; Park, J.-H.; Guenther, A.; Kim, S.

    2016-01-01

    The Amazon basin plays key role in atmospheric chemistry, biodiversity and climate change. In this study we applied nanoelectrospray (nanoESI) ultrahigh resolution mass spectrometry (UHR-MS) for the analysis of the organic fraction of PM2.5 aerosol samples collected during dry and wet seasons at a site in central Amazonia receiving background air masses, biomass burning and urban pollution. Comprehensive mass spectral data evaluation methods (e.g., Kendrick Mass Defect, Van Krevelen diagrams,...

  18. Soil organic matter and fertility of anthropogenic dark earths (Terra Preta de Índio) in the Brazilian Amazon basin Matéria orgânica e fertilidade de solos antropogênicos (Terra Preta De Índio) da Bacia Amazônica brasileira

    OpenAIRE

    Tony Jarbas Ferreira Cunha; Beata Emoke Madari; Luciano Pasqualoto Canellas; Lucedino Paixão Ribeiro; Vinicius de Melo Benites; Gabriel de Araújo Santos

    2009-01-01

    Fertility properties, total C (Ctot), and chemical soil organic matter fractions (fulvic acid fraction - FA, humic acid fraction - HA, humin fraction - H) of anthropogenic dark earths (Terra Preta de Índio) of the Amazon basin were compared with those of Ferralsols with no anthropogenic A horizon. Terra Preta soils had a higher fertility (pH: 5.1-5.4; Sum of bases, SB: 8.93-10.33 cmol c kg-1 , CEC: 17.2-17.5 cmol c kg-1 , V: 51-59 %, P: 116-291 mg kg-1) and Ctot (44.6-44.7 g kg-1) than adjace...

  19. Effects of immigration on the prevalence of malaria in rural areas of the Amazon basin of Brazil Conseqüência da imigração na prevalência da malária nas áreas rurais da bacia Amazônica no Brasil

    OpenAIRE

    Patrick B. Macgreevy; Reynaldo Dietze; Aluísio Prata; Stephen C. Hembree

    1989-01-01

    Epidemiological studies were conducted on malaria in three rural areas of the Amazon basin in the State of Rondônia: the town of Costa Marques, Forte Príncipe da Beira (Fort), and an immigrant settlement in the nearby forest. These studies were instituted to document the malaria problem and to describe the role of immigration on its distribution and prevalence. Hospital records in the town show that the number of malaria cases increased five fold from 1983 to 1987 and that the predominant mal...

  20. New insights into the structure of Om Ali-Thelepte basin, central Tunisia, inferred from gravity data: Hydrogeological implications

    Science.gov (United States)

    Harchi, Mongi; Gabtni, Hakim; El Mejri, Hatem; Dassi, Lassaad; Mammou, Abdallah Ben

    2016-08-01

    This work presents new results from gravity data analyses and interpretation within the Om Ali-Thelepte (OAT) basin, cent