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Sample records for obra na amazonia

  1. Fires in Amazonia

    NASA Astrophysics Data System (ADS)

    Aragão, Luiz E. O. C.; Anderson, Liana O.; Lima, André; Arai, Egidio

    2016-11-01

    Fire has been used since the first humans arrived in Amazonia; however, it has recently become a widely used instrument for large-scale forest clearance. Patterns of fire incidence in the region have been exacerbated by recent drought events. Understanding temporal and spatial fire patterns as well as their consequences for forest structure, species composition, and the carbon cycle is critical for minimising global change impacts on Amazonian ecosystems and people. In this chapter, we provide an overview of the state of our knowledge on the spatial and temporal patterns of fire incidence in Amazonia, depicting the historical fire usage in the region, their relationship with land use and land cover, and their responses to climate seasonality and droughts. We subsequently focus on the impacts of fire, by quantifying the extent of burnt forests during major droughts and describing the main impacts on forest structure, composition, and carbon stocks. Finally, we present an overview of modelling initiatives for forecasting fire incidence in the region. We conclude by providing a comprehensive view of the processes that influence fire occurrence, potential feedbacks, and impacts in Amazonia. We also highlight how key areas within fire ecology must be improved for a better understanding of the long-term effect of fire on the Amazon forest 'biome'.

  2. Fires in Amazonia

    NASA Astrophysics Data System (ADS)

    Aragão, Luiz E. O. C.; Anderson, Liana O.; Lima, André Arai, Egidio

    2016-01-01

    Fire has been used since the first humans arrived in Amazonia; however, it has recently become a widely used instrument for large-scale forest clearance. Patterns of fire incidence in the region have been exacerbated by recent drought events. Understanding temporal and spatial fire patterns as well as their consequences for forest structure, species composition, and the carbon cycle is critical for minimising global change impacts on Amazonian ecosystems and people. In this chapter, we provide an overview of the state of our knowledge on the spatial and temporal patterns of fire incidence in Amazonia, depicting the historical fire usage in the region, their relationship with land use and land cover, and their responses to climate seasonality and droughts. We subsequently focus on the impacts of fire, by quantifying the extent of burnt forests during major droughts and describing the main impacts on forest structure, composition, and carbon stocks. Finally, we present an overview of modelling initiatives for forecasting fire incidence in the region. We conclude by providing a comprehensive view of the processes that influence fire occurrence, potential feedbacks, and impacts in Amazonia. We also highlight how key areas within fire ecology must be improved for a better understanding of the long-term effect of fire on the Amazon forest 'biome'.

  3. An Amazonia Symposium: Mixed Perspectives

    ERIC Educational Resources Information Center

    Huerta, Gloria; Shand, Hope

    1978-01-01

    Reporting on the second symposium on "Amazonia: Extinction or Survival" (Madison, Wisconsin, 1978), this article summarizes papers presented on colonization, health, education, law, etc., and presents the symposium's six resolutions. (JC)

  4. Climate change patterns in Amazonia and biodiversity

    NASA Astrophysics Data System (ADS)

    Cheng, Hai; Sinha, Ashish; Cruz, Francisco W.; Wang, Xianfeng; Edwards, R. Lawrence; D'Horta, Fernando M.; Ribas, Camila C.; Vuille, Mathias; Stott, Lowell D.; Auler, Augusto S.

    2013-01-01

    Precise characterization of hydroclimate variability in Amazonia on various timescales is critical to understanding the link between climate change and biodiversity. Here we present absolute-dated speleothem oxygen isotope records that characterize hydroclimate variation in western and eastern Amazonia over the past 250 and 20 ka, respectively. Although our records demonstrate the coherent millennial-scale precipitation variability across tropical-subtropical South America, the orbital-scale precipitation variability between western and eastern Amazonia exhibits a quasi-dipole pattern. During the last glacial period, our records imply a modest increase in precipitation amount in western Amazonia but a significant drying in eastern Amazonia, suggesting that higher biodiversity in western Amazonia, contrary to ‘Refugia Hypothesis’, is maintained under relatively stable climatic conditions. In contrast, the glacial-interglacial climatic perturbations might have been instances of loss rather than gain in biodiversity in eastern Amazonia, where forests may have been more susceptible to fragmentation in response to larger swings in hydroclimate.

  5. Climate change patterns in Amazonia and biodiversity.

    PubMed

    Cheng, Hai; Sinha, Ashish; Cruz, Francisco W; Wang, Xianfeng; Edwards, R Lawrence; d'Horta, Fernando M; Ribas, Camila C; Vuille, Mathias; Stott, Lowell D; Auler, Augusto S

    2013-01-01

    Precise characterization of hydroclimate variability in Amazonia on various timescales is critical to understanding the link between climate change and biodiversity. Here we present absolute-dated speleothem oxygen isotope records that characterize hydroclimate variation in western and eastern Amazonia over the past 250 and 20 ka, respectively. Although our records demonstrate the coherent millennial-scale precipitation variability across tropical-subtropical South America, the orbital-scale precipitation variability between western and eastern Amazonia exhibits a quasi-dipole pattern. During the last glacial period, our records imply a modest increase in precipitation amount in western Amazonia but a significant drying in eastern Amazonia, suggesting that higher biodiversity in western Amazonia, contrary to 'Refugia Hypothesis', is maintained under relatively stable climatic conditions. In contrast, the glacial-interglacial climatic perturbations might have been instances of loss rather than gain in biodiversity in eastern Amazonia, where forests may have been more susceptible to fragmentation in response to larger swings in hydroclimate.

  6. Amazonia

    SciTech Connect

    Prance, G.T.; Lovejoy, T.E.

    1985-01-01

    IUCN is collaborating in the publication of a series of books on key environments, those areas of our remaining natural environment thought to be most severely threatened by disturbance and destruction. This book, on the Amazon basin, falls into three main parts: the physical setting; the biology; and the human impact. One of the major human impacts at present comes from deforestation, though it is difficult to estimate the rate reliably. Forest burning causes an appreciable amount of air pollution in the dry season. There is little other comment on pollution.

  7. Precipitation chemistry in central Amazonia

    NASA Technical Reports Server (NTRS)

    Andreae, M. O.; Talbot, R. W.; Berresheim, H.; Beecher, K. M.

    1990-01-01

    Rain samples from three sites in central Amazonia were collected over a period of 6 weeks during the 1987 wet season and analyzed for ionic species and dissolved organic carbon. A continuous record of precipitation chemistry and amount was obtained at two of these sites, which were free from local or regional pollution, for a time period of over 1 month. The volume-weighted mean concentrations of most species were found to be about a factor of 5 lower during the wet season compared with previous results from the dry season. Only sodium, potassium, and chloride showed similar concentrations in both seasons. When the seasonal difference in rainfall amount is taken into consideration, the deposition fluxes are only slightly lower for most species during the wet season than during the dry season, again with the exception of chloride, potassium, and sodium. Sodium and chloride are present in the same ratio as in sea salt; rapid advection of air masses of marine origin to the central Amazon Basin during the wet season may be responsible for the observed higher deposition flux of these species. Statistical analysis suggests that sulfate is, to a large extent, of marine (sea salt and biogenic) origin, but that long-range transport of combustion-derived aerosols also makes a significant contribution to sulfate and nitrate levels in Amazonian rain. Organic acid concentrations in rain were responsible for a large fraction of the observed precipitation acidity; their concentration was strongly influenced by gas/liquid interactions.

  8. Non-Official Roads Dilemma in Amazonia

    NASA Technical Reports Server (NTRS)

    Perz, Stephen G.; Arima, Eugenio; Souza, Carlos, Jr.; Caldas, Marcellus; Brandao, Amintas de O., Jr.; Araujo de Souza, Francisco Kennedy; Walker, Robert

    2005-01-01

    At the beginning of this millennium, "non-official" roads predominate in Amazonia. The opening of these roads, a phenomenon that has not been studied in depth, represents a major dilemma - it generates environmental and social impacts, but it helps to reduce the isolation of the communities in Amazonia and to improve the quality of life for those rural populations. The combined positive and negative aspects of this dilemma mean that it is a matter of crucial importance for the government at last to do a proper job in building these roads; if this is disregarded, in the future, the environment and the Brazilians living in that region will be at risk.

  9. The domestication of Amazonia before European conquest

    PubMed Central

    Clement, Charles R.; Denevan, William M.; Heckenberger, Michael J.; Junqueira, André Braga; Neves, Eduardo G.; Teixeira, Wenceslau G.; Woods, William I.

    2015-01-01

    During the twentieth century, Amazonia was widely regarded as relatively pristine nature, little impacted by human history. This view remains popular despite mounting evidence of substantial human influence over millennial scales across the region. Here, we review the evidence of an anthropogenic Amazonia in response to claims of sparse populations across broad portions of the region. Amazonia was a major centre of crop domestication, with at least 83 native species containing populations domesticated to some degree. Plant domestication occurs in domesticated landscapes, including highly modified Amazonian dark earths (ADEs) associated with large settled populations and that may cover greater than 0.1% of the region. Populations and food production expanded rapidly within land management systems in the mid-Holocene, and complex societies expanded in resource-rich areas creating domesticated landscapes with profound impacts on local and regional ecology. ADE food production projections support estimates of at least eight million people in 1492. By this time, highly diverse regional systems had developed across Amazonia where subsistence resources were created with plant and landscape domestication, including earthworks. This review argues that the Amazonian anthrome was no less socio-culturally diverse or populous than other tropical forested areas of the world prior to European conquest. PMID:26202998

  10. The domestication of Amazonia before European conquest.

    PubMed

    Clement, Charles R; Denevan, William M; Heckenberger, Michael J; Junqueira, André Braga; Neves, Eduardo G; Teixeira, Wenceslau G; Woods, William I

    2015-08-07

    During the twentieth century, Amazonia was widely regarded as relatively pristine nature, little impacted by human history. This view remains popular despite mounting evidence of substantial human influence over millennial scales across the region. Here, we review the evidence of an anthropogenic Amazonia in response to claims of sparse populations across broad portions of the region. Amazonia was a major centre of crop domestication, with at least 83 native species containing populations domesticated to some degree. Plant domestication occurs in domesticated landscapes, including highly modified Amazonian dark earths (ADEs) associated with large settled populations and that may cover greater than 0.1% of the region. Populations and food production expanded rapidly within land management systems in the mid-Holocene, and complex societies expanded in resource-rich areas creating domesticated landscapes with profound impacts on local and regional ecology. ADE food production projections support estimates of at least eight million people in 1492. By this time, highly diverse regional systems had developed across Amazonia where subsistence resources were created with plant and landscape domestication, including earthworks. This review argues that the Amazonian anthrome was no less socio-culturally diverse or populous than other tropical forested areas of the world prior to European conquest.

  11. Monitoring Fires in Southwestern Amazonia Rain Forests

    NASA Astrophysics Data System (ADS)

    Brown, I. Foster; Schroeder, Wilfrid; Setzer, Alberto; de Los Rios Maldonado, Monica; Pantoja, Nara; Duarte, Alejandro; Marengo, Jose

    2006-06-01

    From mid-July to mid-October 2005, an environmental disaster unfolded in the trinational region of Madre de Dios, Peru; Acre, Brazil; and Pando, Bolivia (the MAP region), in southwestern Amazonia. A prolonged dry season and human-initiated fires resulted in smoke pollution affecting more than 400,000 persons, fire damage to over 300,000 hectares of rain forest, and over US$50 million of direct economic losses. Indicators suggest that anomalous drought conditions could occur again this year.

  12. Do the recent severe droughts in the Amazonia have the same period of length?

    NASA Astrophysics Data System (ADS)

    Zou, Yong; Macau, Elbert E. N.; Sampaio, Gilvan; Ramos, Antônio M. T.; Kurths, Jürgen

    2016-05-01

    We propose a new measure based on drought period length to assess the temporal difference between the recent two severe droughts of 2005 and 2010 in the Amazonia. The sensitivity of the measure is demonstrated by disclosing the distinct spatial responding mechanisms of the Northeastern and Southwestern Amazon (NA, SA) to the surrounding sea surface temperature (SST) variabilities. The Pacific and Atlantic oceans have different roles on the precipitation patterns in Amazonia. More specifically, the very dry periods in the NA are influenced by El Niño events, while the very dry periods in the SA are affected by the anomalously warming of the SST in the North Atlantic. Our analysis discloses convincingly that the drought 2005 hit SA, which is correlated to the North Atlantic only. Furthermore, it suggests that there are two phases in the drought 2010: (1) it was started in the NA in August 2009 co-occurred with the El Niño event, and (2) later shifted the center of action to SA resulted from anomalously high SST in North Atlantic, which further intensifies the impacts on the spatial coverage.

  13. Carbon stock loss from deforestation through 2013 in Brazilian Amazonia.

    PubMed

    Nogueira, Euler Melo; Yanai, Aurora M; Fonseca, Frederico O R; Fearnside, Philip Martin

    2015-03-01

    The largest carbon stock in tropical vegetation is in Brazilian Amazonia. In this ~5 million km(2) area, over 750,000 km(2) of forest and ~240,000 km(2) of nonforest vegetation types had been cleared through 2013. We estimate current carbon stocks and cumulative gross carbon loss from clearing of premodern vegetation in Brazil's 'Legal Amazonia' and 'Amazonia biome' regions. Biomass of 'premodern' vegetation (prior to major increases in disturbance beginning in the 1970s) was estimated by matching vegetation classes mapped at a scale of 1 : 250,000 and 29 biomass means from 41 published studies for vegetation types classified as forest (2317 1-ha plots) and as either nonforest or contact zones (1830 plots and subplots of varied size). Total biomass (above and below-ground, dry weight) underwent a gross reduction of 18.3% in Legal Amazonia (13.1 Pg C) and 16.7% in the Amazonia biome (11.2 Pg C) through 2013, excluding carbon loss from the effects of fragmentation, selective logging, fires, mortality induced by recent droughts and clearing of forest regrowth. In spite of the loss of carbon from clearing, large amounts of carbon were stored in stands of remaining vegetation in 2013, equivalent to 149 Mg C ha(-1) when weighted by the total area covered by each vegetation type in Legal Amazonia. Native vegetation in Legal Amazonia in 2013 originally contained 58.6 Pg C, while that in the Amazonia biome contained 56 Pg C. Emissions per unit area from clearing could potentially be larger in the future because previously cleared areas were mainly covered by vegetation with lower mean biomass than the remaining vegetation. Estimates of original biomass are essential for estimating losses to forest degradation. This study offers estimates of cumulative biomass loss, as well as estimates of premodern carbon stocks that have not been represented in recent estimates of deforestation impacts.

  14. Predicting pre-Columbian anthropogenic soils in Amazonia

    PubMed Central

    McMichael, C. H.; Palace, M. W.; Bush, M. B.; Braswell, B.; Hagen, S.; Neves, E. G.; Silman, M. R.; Tamanaha, E. K.; Czarnecki, C.

    2014-01-01

    The extent and intensity of pre-Columbian impacts on lowland Amazonia have remained uncertain and controversial. Various indicators can be used to gauge the impact of pre-Columbian societies, but the formation of nutrient-enriched terra preta soils has been widely accepted as an indication of long-term settlement and site fidelity. Using known and newly discovered terra preta sites and maximum entropy algorithms (Maxent), we determined the influence of regional environmental conditions on the likelihood that terra pretas would have been formed at any given location in lowland Amazonia. Terra pretas were most frequently found in central and eastern Amazonia along the lower courses of the major Amazonian rivers. Terrain, hydrologic and soil characteristics were more important predictors of terra preta distributions than climatic conditions. Our modelling efforts indicated that terra pretas are likely to be found throughout ca 154 063 km2 or 3.2% of the forest. We also predict that terra preta formation was limited in most of western Amazonia. Model results suggested that the distribution of terra preta was highly predictable based on environmental parameters. We provided targets for future archaeological surveys under the vast forest canopy and also highlighted how few of the long-term forest inventory sites in Amazonia are able to capture the effects of historical disturbance. PMID:24403329

  15. Predicting pre-Columbian anthropogenic soils in Amazonia.

    PubMed

    McMichael, C H; Palace, M W; Bush, M B; Braswell, B; Hagen, S; Neves, E G; Silman, M R; Tamanaha, E K; Czarnecki, C

    2014-02-22

    The extent and intensity of pre-Columbian impacts on lowland Amazonia have remained uncertain and controversial. Various indicators can be used to gauge the impact of pre-Columbian societies, but the formation of nutrient-enriched terra preta soils has been widely accepted as an indication of long-term settlement and site fidelity. Using known and newly discovered terra preta sites and maximum entropy algorithms (Maxent), we determined the influence of regional environmental conditions on the likelihood that terra pretas would have been formed at any given location in lowland Amazonia. Terra pretas were most frequently found in central and eastern Amazonia along the lower courses of the major Amazonian rivers. Terrain, hydrologic and soil characteristics were more important predictors of terra preta distributions than climatic conditions. Our modelling efforts indicated that terra pretas are likely to be found throughout ca 154 063 km(2) or 3.2% of the forest. We also predict that terra preta formation was limited in most of western Amazonia. Model results suggested that the distribution of terra preta was highly predictable based on environmental parameters. We provided targets for future archaeological surveys under the vast forest canopy and also highlighted how few of the long-term forest inventory sites in Amazonia are able to capture the effects of historical disturbance.

  16. Ocelot (Leopardus pardalis) Density in Central Amazonia

    PubMed Central

    da Rocha, Daniel Gomes; Sollmann, Rahel; Ramalho, Emiliano Esterci; Ilha, Renata; Tan, Cedric K. W.

    2016-01-01

    Ocelots (Leopardus pardalis) are presumed to be the most abundant of the wild cats throughout their distribution range and to play an important role in the dynamics of sympatric small-felid populations. However, ocelot ecological information is limited, particularly for the Amazon. We conducted three camera-trap surveys during three consecutive dry seasons to estimate ocelot density in Amanã Reserve, Central Amazonia, Brazil. We implemented a spatial capture-recapture (SCR) model that shared detection parameters among surveys. A total effort of 7020 camera-trap days resulted in 93 independent ocelot records. The estimate of ocelot density in Amanã Reserve (24.84 ± SE 6.27 ocelots per 100 km2) was lower than at other sites in the Amazon and also lower than that expected from a correlation of density with latitude and rainfall. We also discuss the importance of using common parameters for survey scenarios with low recapture rates. This is the first density estimate for ocelots in the Brazilian Amazon, which is an important stronghold for the species. PMID:27191598

  17. Ocelot (Leopardus pardalis) Density in Central Amazonia.

    PubMed

    Rocha, Daniel Gomes da; Sollmann, Rahel; Ramalho, Emiliano Esterci; Ilha, Renata; Tan, Cedric K W

    2016-01-01

    Ocelots (Leopardus pardalis) are presumed to be the most abundant of the wild cats throughout their distribution range and to play an important role in the dynamics of sympatric small-felid populations. However, ocelot ecological information is limited, particularly for the Amazon. We conducted three camera-trap surveys during three consecutive dry seasons to estimate ocelot density in Amanã Reserve, Central Amazonia, Brazil. We implemented a spatial capture-recapture (SCR) model that shared detection parameters among surveys. A total effort of 7020 camera-trap days resulted in 93 independent ocelot records. The estimate of ocelot density in Amanã Reserve (24.84 ± SE 6.27 ocelots per 100 km2) was lower than at other sites in the Amazon and also lower than that expected from a correlation of density with latitude and rainfall. We also discuss the importance of using common parameters for survey scenarios with low recapture rates. This is the first density estimate for ocelots in the Brazilian Amazon, which is an important stronghold for the species.

  18. Factors Controlling Liquid Particulate Matter in Amazonia

    NASA Astrophysics Data System (ADS)

    Bateman, A. P.; Gong, Z.; de Sá, S. S.; Wernis, R. A.; Yee, L.; Isaacman-VanWertz, G. A.; Goldstein, A. H.; Castillo, P.; Sedlacek, A. J., III; Palm, B. B.; Campuzano-Jost, P.; Day, D. A.; Hu, W.; Jimenez, J. L.; Alexander, L.; Manzi, A. O.; Souza, R. A. F. D.; Artaxo, P.; Martin, S. T.

    2015-12-01

    The hygroscopic response of particulate matter (PM) during GoAmazon 2014/5 was investigated through the use of particle rebound (or lack thereof) during impaction. The hygroscopic response was measured online and in real-time using a custom designed impaction apparatus. The impaction apparatus was calibrated with respect to particle viscosity indicating a liquid state (viscosity <102 Pa s) for complete adherence (no particle rebound). By varying the PM water content and observing particle rebound as a function of RH (up to 98%), the hygroscopic response and phase state of the PM under investigation was determined. The hygroscopic response curves were categorized according to the rebound fraction at high RH (80 - 98%) bounded by two extremes. 1) Time periods that resemble pure SOM generated under controlled chamber conditions, where no particle rebound is observed above 80% RH. 2) Time periods that a large fraction (10 - 40%) of particles rebound at RH values >95%, an indication of hydrophobic particles. The role of anthropogenic and biogenic factors in controlling the hygroscopic response of PM in Amazonia is investigated through meteorological conditions and particle chemical composition.

  19. Dynamics, Patterns and Causes of Fires in Northwestern Amazonia

    PubMed Central

    Armenteras, Dolors; Retana, Javier

    2012-01-01

    According to recent studies, two widespread droughts occurred in the Amazon basin, one during 2005 and one during 2010. The drought increased the prevalence of climate-driven fires over most of the basin. Given the importance of human-atmosphere-vegetation interactions in tropical rainforests, these events have generated concerns over the vulnerability of this area to climate change. This paper focuses on one of the wettest areas of the basin, Northwestern Amazonia, where the interactions between the climate and fires are much weaker and where little is known about the anthropogenic drivers of fires. We have assessed the response of fires to climate over a ten-year period, and analysed the socio-economic and demographic determinants of fire occurrence. The patterns of fires and climate and their linkages in Northwestern Amazonia differ from the enhanced fire response to climate variation observed in the rest of Amazonia. The highest number of recorded fires in Northwestern Amazonia occurred in 2004 and 2007, and this did not coincide with the periods of extreme drought experienced in Amazonia in 2005 and 2010. Rather, during those years, Northwestern Amazonia experienced a relatively small numbers of fire hotspots. We have shown that fire occurrence correlated well with deforestation and was determined by anthropogenic drivers, mainly small-scale agriculture, cattle ranching (i.e., pastures) and active agricultural frontiers (including illegal crops). Thus, the particular climatic conditions for air convergence and rainfall created by proximity to the Andes, coupled with the presence of one of the most active colonisation fronts in the region, make this region differently affected by the general drought-induced fire patterns experienced by the rest of the Amazon. Moreover, the results suggest that, even in this wet region, humans are able to modify the frequency of fires and impact these historically well preserved forests. PMID:22523580

  20. Dynamics, patterns and causes of fires in Northwestern Amazonia.

    PubMed

    Armenteras, Dolors; Retana, Javier

    2012-01-01

    According to recent studies, two widespread droughts occurred in the Amazon basin, one during 2005 and one during 2010. The drought increased the prevalence of climate-driven fires over most of the basin. Given the importance of human-atmosphere-vegetation interactions in tropical rainforests, these events have generated concerns over the vulnerability of this area to climate change. This paper focuses on one of the wettest areas of the basin, Northwestern Amazonia, where the interactions between the climate and fires are much weaker and where little is known about the anthropogenic drivers of fires. We have assessed the response of fires to climate over a ten-year period, and analysed the socio-economic and demographic determinants of fire occurrence. The patterns of fires and climate and their linkages in Northwestern Amazonia differ from the enhanced fire response to climate variation observed in the rest of Amazonia. The highest number of recorded fires in Northwestern Amazonia occurred in 2004 and 2007, and this did not coincide with the periods of extreme drought experienced in Amazonia in 2005 and 2010. Rather, during those years, Northwestern Amazonia experienced a relatively small numbers of fire hotspots. We have shown that fire occurrence correlated well with deforestation and was determined by anthropogenic drivers, mainly small-scale agriculture, cattle ranching (i.e., pastures) and active agricultural frontiers (including illegal crops). Thus, the particular climatic conditions for air convergence and rainfall created by proximity to the Andes, coupled with the presence of one of the most active colonisation fronts in the region, make this region differently affected by the general drought-induced fire patterns experienced by the rest of the Amazon. Moreover, the results suggest that, even in this wet region, humans are able to modify the frequency of fires and impact these historically well preserved forests.

  1. The mitogenome of Onchocerca volvulus from the Brazilian Amazonia focus

    PubMed Central

    Crainey, James L; da Silva, Túllio RR; Encinas, Fernando; Marín, Michel A; Vicente, Ana Carolina P; Luz, Sérgio LB

    2016-01-01

    We report here the first complete mitochondria genome of Onchocerca volvulus from a focus outside of Africa. An O. volvulus mitogenome from the Brazilian Amazonia focus was obtained using a combination of high-throughput and Sanger sequencing technologies. Comparisons made between this mitochondrial genome and publicly available mitochondrial sequences identified 46 variant nucleotide positions and suggested that our Brazilian mitogenome is more closely related to Cameroon-origin mitochondria than West African-origin mitochondria. As well as providing insights into the origins of Latin American onchocerciasis, the Brazilian Amazonia focus mitogenome may also have value as an epidemiological resource. PMID:26814648

  2. The mitogenome of Onchocerca volvulus from the Brazilian Amazonia focus.

    PubMed

    Crainey, James L; Silva, Túllio R R da; Encinas, Fernando; Marín, Michel A; Vicente, Ana Carolina P; Luz, Sérgio L B

    2016-01-01

    We report here the first complete mitochondria genome of Onchocerca volvulus from a focus outside of Africa. An O. volvulus mitogenome from the Brazilian Amazonia focus was obtained using a combination of high-throughput and Sanger sequencing technologies. Comparisons made between this mitochondrial genome and publicly available mitochondrial sequences identified 46 variant nucleotide positions and suggested that our Brazilian mitogenome is more closely related to Cameroon-origin mitochondria than West African-origin mitochondria. As well as providing insights into the origins of Latin American onchocerciasis, the Brazilian Amazonia focus mitogenome may also have value as an epidemiological resource.

  3. Hypotheses to explain the origin of species in Amazonia.

    PubMed

    Haffer, J

    2008-11-01

    The main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different factors, as follow: (1) Changes in the distribution of land and sea or in the landscape due to tectonic movements or sea level fluctuations (Paleogeography hypothesis), (2) the barrier effect of Amazonian rivers (River hypothesis), (3) a combination of the barrier effect of broad rivers and vegetational changes in northern and southern Amazonia (River-refuge hypothesis), (4) the isolation of humid rainforest blocks near areas of surface relief in the periphery of Amazonia separated by dry forests, savannas and other intermediate vegetation types during dry climatic periods of the Tertiary and Quaternary (Refuge hypothesis), (5) changes in canopy-density due to climatic reversals (Canopy-density hypothesis) (6) the isolation and speciation of animal populations in small montane habitat pockets around Amazonia due to climatic fluctuations without major vegetational changes (Museum hypothesis), (7) competitive species interactions and local species isolations in peripheral regions of Amazonia due to invasion and counterinvasion during cold/warm periods of the Pleistocene (Disturbance-vicariance hypothesis) and (8) parapatric speciation across steep environmental gradients without separation of the respective populations (Gradient hypothesis). Several of these hypotheses probably are relevant to a different degree for the speciation processes in different faunal groups or during different geological periods. The basic paleogeography model refers mainly to faunal differentiation during the Tertiary and in combination with the Refuge hypothesis. Milankovitch cycles leading to global main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different

  4. Selective Logging, Fire, and Biomass in Amazonia

    NASA Technical Reports Server (NTRS)

    Houghton, R. A.

    1999-01-01

    Biomass and rates of disturbance are major factors in determining the net flux of carbon between terrestrial ecosystems and the atmosphere, and neither of them is well known for most of the earth's surface. Satellite data over large areas are beginning to be used systematically to measure rates of two of the most important types of disturbance, deforestation and reforestation, but these are not the only types of disturbance that affect carbon storage. Other examples include selective logging and fire. In northern mid-latitude forests, logging and subsequent regrowth of forests have, in recent decades, contributed more to the net flux of carbon between terrestrial ecosystems and the atmosphere than any other type of land use. In the tropics logging is also becoming increasingly important. According to the FAO/UNEP assessment of tropical forests, about 25% of total area of productive forests have been logged one or more times in the 60-80 years before 1980. The fraction must be considerably greater at present. Thus, deforestation by itself accounts for only a portion of the emissions carbon from land. Furthermore, as rates of deforestation become more accurately measured with satellites, uncertainty in biomass will become the major factor accounting for the remaining uncertainty in estimates of carbon flux. An approach is needed for determining the biomass of terrestrial ecosystems. 3 Selective logging is increasingly important in Amazonia, yet it has not been included in region-wide, satellite-based assessments of land-cover change, in part because it is not as striking as deforestation. Nevertheless, logging affects terrestrial carbon storage both directly and indirectly. Besides the losses of carbon directly associated with selective logging, logging also increases the likelihood of fire.

  5. Rupturing of Biological Spores As a Source of Secondary Particles in Amazonia.

    PubMed

    China, Swarup; Wang, Bingbing; Weis, Johannes; Rizzo, Luciana; Brito, Joel; Cirino, Glauber G; Kovarik, Libor; Artaxo, Paulo; Gilles, Mary K; Laskin, Alexander

    2016-11-15

    Airborne biological particles, such as fungal spores and pollen, are ubiquitous in the Earth's atmosphere and may influence the atmospheric environment and climate, impacting air quality, cloud formation, and the Earth's radiation budget. The atmospheric transformations of airborne biological spores at elevated relative humidity remain poorly understood and their climatic role is uncertain. Using an environmental scanning electron microscope (ESEM), we observed rupturing of Amazonian fungal spores and subsequent release of submicrometer size fragments after exposure to high humidity. We find that fungal fragments contain elements of inorganic salts (e.g., Na and Cl). They are hygroscopic in nature with a growth factor up to 2.3 at 96% relative humidity, thus they may potentially influence cloud formation. Due to their hygroscopic growth, light scattering cross sections of the fragments are enhanced by up to a factor of 10. Furthermore, rupturing of fungal spores at high humidity may explain the bursting events of new particle formation in Amazonia.

  6. Catalogue of distribution of lizards (Reptilia: Squamata) from the Brazilian Amazonia. II. Gekkonidae, Phyllodactylidae, Sphaerodactylidae.

    PubMed

    Ribeiro-Júnior, Marco A

    2015-07-02

    I present distribution data of all geckos (Gekkonidae, Phyllodactylidae and Sphaerodactylidae) known from the Brazilian Amazonia, totaling 19 species, belonging to nine genera. This represents six more taxa than previously reported for these families. Data were based on the direct examination of 23,094 specimens deposited in three North American and eight Brazilian museums. Most species (68.4%) are endemic to the Amazonia; non-endemic species are mainly associated with open dry (semideciduous) forest or open vegetation (savanna) enclaves in Amazonia. As a whole, three taxa are widespread in Amazonia, two are restricted to eastern Amazonia, two to western Amazonia, three to northern Amazonia (either widespread or restriced to parts of the Guiana region), one to southern Amazonia, one to southwestern Amazonia, and three to the southern peripheral portion of Amazonia. Additionally, four species have unique distributions and four species have a distribution that is congruent with one of the areas of endemism recognized for other organisms (birds and primates), of which two occur in the area of endemism of Guiana, one in Inambari, and one in Tapajós.

  7. Catalogue of distribution of lizards (Reptilia: Squamata) from the Brazilian Amazonia. III. Anguidae, Scincidae, Teiidae.

    PubMed

    Ribeiro-Júnior, Marco A; Amaral, Silvana

    2016-12-09

    We present distribution data of all Anguidae, Scincidae, and Teiidae lizards known from the Brazilian Amazonia, totaling 29 species-level taxa, belonging to 14 genera. This represents 11 more species-level taxa than previously reported for these families in this area. Data were based on literature and 46,806 specimens deposited in three North American and eight Brazilian museums, including the main collections harboring Amazonian material. Most species (~55%) are endemic to Amazonia. Except for Ameiva ameiva, that is present in several environments and domains, non-endemic species are either associated with open dry (semideciduous) forest or open vegetation (savanna) enclaves in Amazonia, occupying similar environments outside Amazonia, gallery forests within the Cerrado, or present disjunct populations in the Atlantic Forest. As a whole, six taxa are widespread in Amazonia, four are restricted to eastern Amazonia, four to western Amazonia, three to southwestern Amazonia, one to northern Amazonia, and seven to the southern peripheral portion of Amazonia. Besides, two species present apparently more restricted, unique distributions. Only three species have a distribution that is congruent with one of the areas of endemism (AE) recognized for other organisms (birds and primates), of which two occur in AE Guiana and one in AE Inambari.

  8. Were Amazonia and Baltica Connected in Nuna and Rodinia?

    NASA Astrophysics Data System (ADS)

    Bogdanova, S. V.; Pisarevsky, S. A.

    2015-12-01

    Most of paleogeographic reconstructions of Proterozoic supercontinents Rodinia and Nuna consider a long-lived connection between Baltica and Amazonia/West Africa between 1.8 and 1.0 Ga. This connection implies a common Paleo-to-Mesoproterozoic accretionary margin of south-western Baltica and Amazonia. We tested the validity of this hypothesis by the time-space analysis of the crustal growth of major tectonic domains in these cratons and their possible relationships. We analysed a subduction polarity, gaps in juvenile crustal growth, "stitching" magmatism and sedimentary basins as well as SLIP and LIP events. In doing so, we found several mismatches between respective domains of these cratons: (a) their chronologies and "barcodes" of magmatism are mostly non-correlative; (b) their subduction directions were different, e. g. at 2.0-1.90, 1.80-1.75, and 1.0 Ga; (c) accretionary crustal growth of Baltica was semi-continuous during 500 m. y. (2.0 to1.5 Ga), while in Amazonia production of juvenile crust occurred in relatively short, 100-200 m.y. periods (2.0-1.9 and 1.55-1.35 Ga) with 100-150 m. y. gaps; (d) subduction stopped in Baltica between 1.45 and 1.2 Ga but continued in Amazonia at the same time; (e) some parts of Amazonian provinces could be incorporated microcontinents like Rio Negro(?) and Paragua; (f) Baltica escaped the 1.89-1.87 Ga SLIP and 1.8-1.75 Ga LIP events, which broadly disturbed Amazonia. Several apparently coeval periods of crustal growth and tectonism in Amazonia and Baltica (1.8-1.75, 1.59-1.52, 1.50-1.40, 1.1-0.95Ga) we interpret as indicators of global plate reorganization and continent rotations. Careful analysis of available Mesoproterozoic paleomagnetic data from Baltica and Amazonia also does not support a long-lived integrity of these cratons.

  9. The Frequency and Fate of Understory Forest Fires in Amazonia

    NASA Astrophysics Data System (ADS)

    Morton, D. C.; le page, Y.; Wang, D.; Chen, Y.; Randerson, J. T.; Collatz, G. J.; Giglio, L.; Hurtt, G. C.; DeFries, R. S.

    2012-12-01

    Fires for deforestation or agricultural management frequently escape their intended boundaries and burn standing Amazon forests. The extent and frequency of understory forest fires are critical to assess forest carbon emissions and the long-term legacy of understory fires in Amazonia. Patterns of understory fire activity under current climate conditions also offer a blueprint for potential changes in Amazon forests under scenarios of future climate and land use. Here, we estimated of the extent and frequency of understory forest fires for the entire arc of deforestation in southern Amazonia using a time series of annual Moderate Resolution Imaging Spectroradiometer (MODIS) data. Understory forest fires burned more than 80,000 km2 during 1999-2010. Fires were widespread along the southern and eastern extents of Amazon forests during the four years with highest fire activity (1999, 2005, 2007, 2010). The interannual variability in understory fires offered new insights into fire-climate dynamics in Amazonia over a range of temporal scales, based on the combination of burned area, MODIS active fire detections, and reanalysis climate data. Initial fire exposure reduces aboveground carbon stocks, and frequent fires are one possible mechanism for long-term changes the structure of Amazon forests. Repeated burning was concentrated in southeastern Amazonia, and >95% of all repeated fires occurred in the Brazilian states of Mato Grosso and Pará. Forests that burned two or more times during this period accounted for 16% of understory fire activity. Finally, deforestation of burned forests was rare, suggesting that forest degradation from understory fires was an independent source of carbon emissions during this period. Modeling the time scales of carbon loss and recovery in burned forests is therefore critical to estimate the net carbon emissions from these fires. The results of this study suggest that understory fires operate as a large-scale edge effect in Amazonia, as

  10. Is deforestation driving Southeastern Amazonia's hydrological transition?

    NASA Astrophysics Data System (ADS)

    Arias, M. E.; Lee, E.; Farinosi, F.; Moorcroft, P. R.; Pereira, F. F.

    2015-12-01

    Changes in forest cover are critical for the maintenance of the hydrological cycle in tropical forests and surrounding landscapes. Most evidence suggesting impacts of deforestation on river flows comes from local scale and short duration experiments, but these are largely prohibited in vast and inaccessible areas of the Amazon. Although rainfall-runoff models are commonly used to scale up deforestation effects to regional scales and multidecadal time ranges, most of these models assume static land use/land cover, excluding temporal variability in human disturbance in decadal long simulations. This presentation will present a study carried out in the Tapajos River in Brazil, a large basin in southeast Amazonia, where we aim to understand the role of human disturbance and vegetation dynamics on river flows. This study analyzed spatial and temporal trends in observed rainfall, forest cover, and river flow indicators for 1970s to 2000s. During this period, no significant changes occur in total annual rainfall, while over 140,000 km2 (35% of original cover) of forest were cleared. Contrary to the expected response following deforestation, 90-day minimum river flows showed a significant decrease though most gauges in the basin. In order to isolate deforestation effects, two contrasting scenarios were computed at a daily scale using the Ecosystem Demography Model 2 in combination with a water flow routing scheme; the first scenario incorporated natural disturbance resembling 1970 forest conditions, while the second scenario incorporated both natural and human disturbance (aka., land use conversion), the later as observed annually from the 1970s to the 2000s. We estimated that deforestation began affecting dry season flows in the early 1990s once less than 10% of the original forest cover was lost. Also, a potential effect of deforestation on the timing of rainfall-flow responses was also detected in the lower river gauges. While the estimated effects on timing are also

  11. The first species of the genus Caponina from Brazilian Amazonia (Araneae: Caponiidae).

    PubMed

    Brescovit, Antonio D; Ruiz, Alexander Sánchez

    2013-01-01

    The genus Caponina Simon, 1891 comprises eleven species of medium-sized, soil-dwelling caponiids. Most members of Caponina have six eyes, but some have five, four, three or two eyes (Brignoli 1977, Platnick 1994). The genus is widespread in South and Central America (Platnick 2012). To date, only three species have been recorded from Brazil: Caponina alegre Platnick, 1994 from the state of Rio Grande do Sul, C. notabilis (Mello-Leitão, 1939) from the states of Paraná and Rio Grande do Sul, and C. tijuca Platnick, 1994 from the state of Rio de Janeiro (Platnick 1994). In this paper we describe a new species from the state of Pará, in Brazilian Amazonia. Caponina papamanga new species was collected during the "Butantan na Amazonia" project, founded by the Instituto Butantan. The phylogenetic relationships of C. papamanga could not be studied, but the greatly elongated embolus, the dorsal tubercle on the palpal femur (Figs. 7, 9) and the massive epigynal sclerotizations (Fig. 10) suggest that this species belongs to the monophyletic Andean group proposed by Platnick (1994: 7). All morphological observations and illustrations were made using a Leica MZ12 stereomicroscope with camera lucida. The epigynum was dissected and immersed in clove oil for visualization of internal structures following Levi (1965). Descriptions and measurements follow Platnick (1994). Measurements are given in millimeters. Scanning electron microscope (SEM) images were taken using a Jeol-JSM-5200 with attached SLR digital camera. The material examined was deposited in the collections of the Instituto Butantan, Sgo Paulo (IBSP, curator: D.M. Barros Battesti) and the Museu Paraense Emílio Goeldi, Belém (MPEG, curator: A.B. Bonaldo).

  12. Navigating Amazonia under uncertainty: past, present and future environmental governance.

    PubMed

    Boyd, Emily

    2008-05-27

    One of the major environmental challenges of the twenty-first century is the continued rapid deforestation of Amazonia. The 2005 dieback crisis emphasizes the unprecedented challenges facing Brazil. The examination of past and present institutions for ecosystem management, in Amazonia, shows structural barriers across public, private and community arrangements. The adaptive governance concept helps to understand why these institutions are failing to deliver sustainable futures. In looking forward, it is encouraging to see that important networks of knowledge and a number of novel initiatives are emerging in Brazil. These new arrangements are novel in the way that they seem to be adaptive and navigate structures in the hope of overcoming insurmountable drivers of deforestation.

  13. The logic of livestock and deforestation in Amazonia

    SciTech Connect

    Hecht, S.B. )

    1993-11-01

    Most cleared forest in Latin America's lowland tropics will eventually become pasture. The incineration of large areas of high-biomass forest in Amazonia currently generates 10-15% of the total carbon additions to the atmosphere. This article analyzes the logic and economics of livestock in Amazonia by evaluating the various means of making profits from land and natural-resource capital. It also discusses how the Amazonian livestock sector is closely linked to virtually every other rural development activity. These links establish a framework for analyzing deforestation patterns. The analysis qualifies some of the current explanations of deforestation. Finally, current approaches to diminishing this destructive land use are discussed. 51 refs., 1 fig., 3 tabs.

  14. Amazonia and the modern carbon cycle: lessons learned.

    PubMed

    Ometto, Jean Pierre H B; Nobre, Antonio D; Rocha, Humberto R; Artaxo, Paulo; Martinelli, Luiz A

    2005-05-01

    In this paper, we review some critical issues regarding carbon cycling in Amazonia, as revealed by several studies conducted in the Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA). We evaluate both the contribution of this magnificent biome for the global net primary productivity/net ecosystem exchange (NPP/NEE) and the feedbacks of climate change on the dynamics of Amazonia. In order to place Amazonia in a global perspective and make the carbon flux obtained through the LBA project comparable with global carbon budgets, we extrapolated NPP/NEE values found by LBA studies to the entire area of the Brazilian Amazon covered by rainforest. The carbon emissions due to land use changes for the tropical regions of the world produced values from 0.96 to 2.4 Pg C year(-1), while atmospheric CO2 inversion models have recently indicated that tropical lands in the Americas could be exchanging a net 0.62+/-1.15 Pg C year(-1) with the atmosphere. The difference calculated from these two methods would imply a local sink of approximately 1.6-1.7 Pg C year(-1), or a source of 0.85 ton C ha(-1) year(-1). Using our crude extrapolation of LBA values for the Amazon forests (5 million km2) we estimate a range for the C flux in the region of -3.0 to 0.75 Pg C year(-1). The exercise here does not account for environmental variability across the region, but it is an important driver for present and future studies linking local process (i.e. nutrient availability, photosynthetic capacity, and so forth) to global and regional dynamic approaches.

  15. Catalogue of distribution of lizards (Reptilia: Squamata) from the Brazilian Amazonia. I. Dactyloidae, Hoplocercidae, Iguanidae, Leiosauridae, Polychrotidae, Tropiduridae.

    PubMed

    Ribeiro-Júnior, Marco A

    2015-07-08

    I present distribution data of all Dactyloidae, Hoplocercidae, Iguanidae, Leiosauridae, Polychrotidae and Tropiduridae lizards known from the Brazilian Amazonia, totaling 40 species-level taxa, belonging to 11 genera. This represents four more species-level taxa than previously reported for these families. Data were based on the direct examination of 41,243 specimens deposited in three North American and eight Brazilian musea, including the main collections harboring Amazonian material. Most species (62.5%) are endemic to the Amazonia; non-endemic species are mainly associated with open dry (semideciduous) forest or open vegetation (savanna) enclaves in Amazonia, with a few exceptions. As a whole, seven taxa are widespread in Amazonia, one is restricted to eastern Amazonia, three to western Amazonia, five to northern Amazonia (either in part of it or widespread in the Guiana region), two to northwestern Amazonia, one to southern Amazonia, nine to southwestern Amazonia, and seven to the southern peripheral portion of Amazonia. Five species have unique distributions and five species have a distribution that is congruent with one of the areas of endemism (AE) recognized for other organisms (birds and primates). The first herpetological gazetteer for the Brazilian Amazonia with about 3,600 georeferenced localities was also produced.

  16. Labrets in Africa and Amazonia: medical implications and cultural determinants.

    PubMed

    Garve, Roland; Garve, Miriam; Türp, Jens C; Meyer, Christian G

    2017-02-01

    The custom of wearing labrets has a long tradition. Labrets appeared independently several thousand years ago in various culture groups in Asia, Europe, Africa and the Americas. Today, apart from diverse body modifications as increasingly practiced in western civilisations, lip plates and plugs are found among a small number of tribal groups only in Africa and Amazonia. We summarise the history of labrets in different societies, describe medical consequences of wearing lip plates and plugs for jaws and teeth and address relevant cultural issues.

  17. Surface Ozone Enrichment Downwind of Manaus City, in Central Amazonia

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    Amazonia is a unique place to study the impact of anthropogenic emissions on atmospheric photochemistry, fueled by large inputs of solar radiation, humidity, biogenic emissions and turbulent mixing. In the wet season, thousands of km2 of Amazonian forest areas can be considered pristine, whereas in the dry season biomass burning emissions in regional scale add to picture. The Amazon region is also going through localized urban development, in particular, the Manaus city, with 2 million inhabitants. The GoAmazon2014/5 experiment seeks to understand the interactions between urban and biogenic emissions in Amazonia. The combination of biogenic volatile organic compounds and urban NOx emissions is expected to increase tropospheric O3 production, with impacts to the ecosystem and human health. To investigate this issue, surface O3 measurements were taken between Feb and Dec 2014 at two sites in Amazonia: T2, located in the outflow of the Manaus urban plume, and T3, sitting 60 km downwind of the city. The influence of the urban plume at T3 site was detected by a combination of typical ΔCN/ΔCO ratios, Hysplit backtrajectories and threshold concentrations of tracers such as particle number and black carbon. The transport from T2 to T3 typically lasted 7 hours. At T2, the O3 diurnal cycle showed a diurnal peak of 20 ppb in the wet season and of 35 ppb in the dry season, suggesting the contribution of regional biomass burning to O3 photochemical production. In the absence of urban or biomass burning emissions, O3 diurnal cycle at T3 showed a peak of 15 ppb, similar to observations taken in pristine forest areas in Amazonia. When the Manaus plume reached the T3 site in the afternoon, the diurnal O3 peak increased to 40 ppb, indicating a net O3 production rate of 3.6 ppb h-1 along this diurnal transport. When the Manaus plume reached the T3 site before sunrise, i.e., a transport during the night, the diurnal peak was anticipated and reached 25 ppb.

  18. The expansion of intensive agriculture and ranching in Brazilian Amazonia

    NASA Astrophysics Data System (ADS)

    Walker, Robert; DeFries, Ruth; del Carmen Vera-Diaz, Maria; Shimabukuro, Yosio; Venturieri, Adriano

    Agriculture in Amazonia has often provoked controversy, given the tremendous ecological value of the region's environment. First with ranching, and now with the soybean boom, tractors and cattle have marched across lands that for millennia supported only closed moist forest, resident ecosystems, and dispersed indigenous peoples. The present chapter considers this expansion, focusing on the Brazilian portion of the basin. Its premise is that effective Amazonian policy must be grounded on an understanding of the region's agriculture. The chapter pursues its objectives by first addressing the development initiatives that created the preconditions for Amazonia's current agricultural economy. The region is remote and has therefore required sustained government intervention to release its potential. The policy discussion is followed by descriptions of cattle ranching and soy farming. For each, market settings and trajectories of expansion are presented. Although these sectoral descriptions are data rich, they do not provide a conceptual framework for analyzing the environmental impacts of evolving market conditions. To accomplish this, the chapter invokes the classical land use model of von Thünen to explain Amazonian land cover dynamics in relation to soy-cattle linkages. It addresses these dynamics with remote sensing data from Mato Grosso, Pará, and Rondônia, and then discusses scenarios of agricultural advances on the forest. Conclusions follow, considering possible policy responses to deforestation, and the social context of agricultural intensification, with special attention to the issues of land tenure security and distributional equity.

  19. Secondary Forests from Agricultural Abandonment in Amazonia 2000-2009

    NASA Technical Reports Server (NTRS)

    Morton, Douglas

    2010-01-01

    Ongoing negotiations to include reducing emissions from tropical deforestation and forest degradation (REDD+) in a post-Kyoto climate agreement highlight the critical role of satellite data for accurate and transparent accounting of forest cover changes. In addition to deforestation and degradation, knowledge of secondary forest dynamics is essential for full carbon accounting under REDD+. Land abandonment to secondary forests also frames one of the key tradeoffs for agricultural production in tropical forest countries-whether to incentivize secondary forest growth (for carbon sequestration and biodiversity conservation) or low-carbon expansion of agriculture or biofuels production in areas of secondary forests. We examined patterns of land abandonment to secondary forest across the arc of deforestation in Brazil and Bolivia using time series of annual Landsat and MODIS data from 2000-2009. Rates of land abandonment to secondary forest during 2002-2006 were less than 5% of deforestation rates in these years. Small areas of new secondary forest were scattered across the entire arc of deforestation, rather than concentrated in any specific region of the basin. Taken together, our analysis of the satellite data record emphasizes the difficulties of addressing the pool of new secondary forests in the context of REDD+ in Amazonia. Due to the small total area of secondary forests, land sparing through agricultural intensification will be an important element of efforts to reduce deforestation rates under REDD+ while improving agricultural productivity in Amazonia.

  20. Rupturing of Biological Spores As a Source of Secondary Particles in Amazonia

    SciTech Connect

    China, Swarup; Wang, Bingbing; Weis, Johannes; Rizzo, Luciana; Brito, Joel; Cirino, Glauber G.; Kovarik, Libor; Artaxo, Paulo; Gilles, Mary K.; Laskin, Alexander

    2016-11-15

    Airborne biological particles, such as fungal spores and pollen, are ubiquitous in the Earth’s atmosphere and play an important role in the atmospheric environment and climate, impacting air quality, cloud formation, and the Earth’s radiation budget. The atmospheric transformations of airborne biological spores at elevated relative humidity remain poorly understood and their climatic role is uncertain. Using an environmental scanning electron microscope (ESEM), we observed rupturing of Amazonian fungal spores and subsequent release of nanometer to submicron size fragments after exposure to high humidity. We find that fungal fragments contain elements of inorganic salts (e.g., Na and Cl). They are hygroscopic in nature with a growth factor up to 2.3 at 96% relative humidity, thus they may potentially influence cloud formation. Due to their hygroscopic growth, light scattering cross sections of the fragments are enhanced by up to a factor of 10. Furthermore, rupturing of fungal spores at high humidity may explain the bursting events of nanoparticles and may provide insight into new particle formation in Amazonia.

  1. Drug tourism or spiritual healing? Ayahuasca seekers in Amazonia.

    PubMed

    Winkelman, Michael

    2005-06-01

    This research addresses the question of whether Westerners who seek traditional spiritual medicine known as ayahuasca can be best characterized as "drug tourists" or as people pursuing spiritual and therapeutic opportunities. Participants in an ayahuasca retreat in Amazonia were interviewed regarding their motivations for participation and the benefits they felt that they received. These findings from the interviews were organized to reveal common motivations and benefits. Contrary to the characterization as "drug tourists", the principal motivations can be characterized as: seeking spiritual relations and personal spiritual development; emotional healing; and the development of personal self-awareness, including contact with a sacred nature, God, spirits and plant and natural energies produced by the ayahuasca. The motivation and perceived benefits both point to transpersonal concerns, with the principal perceived benefits involving increased self awareness, insights and access to deeper levels of the self that enhanced personal development and the higher self, providing personal direction in life.

  2. Sparse pre-Columbian human habitation in western Amazonia.

    PubMed

    McMichael, C H; Piperno, D R; Bush, M B; Silman, M R; Zimmerman, A R; Raczka, M F; Lobato, L C

    2012-06-15

    Locally extensive pre-Columbian human occupation and modification occurred in the forests of the central and eastern Amazon Basin, but whether comparable impacts extend westward and into the vast terra firme (interfluvial) zones, remains unclear. We analyzed soils from 55 sites across central and western Amazonia to assess the history of human occupation. Sparse occurrences of charcoal and the lack of phytoliths from agricultural and disturbance species in the soils during pre-Columbian times indicated that human impacts on interfluvial forests were small, infrequent, and highly localized. No human artifacts or modified soils were found at any site surveyed. Riverine bluff areas also appeared less heavily occupied and disturbed than similar settings elsewhere. Our data indicate that human impacts on Amazonian forests were heterogeneous across this vast landscape.

  3. An empirical approach to retrieve Evapotranspiration over Amazonia

    NASA Astrophysics Data System (ADS)

    Juarez, R.; Fu, R.; Myneni, R.; Bernardes, S.; Gao, H.

    2006-12-01

    The estimation of regional evapotranspiration (ET) over Amazonia remains uncertain since there are very few in situ observational with a limited footprint (~1km). The present work uses an empirical method to estimate ET over the Brazilian Legal Amazon (BLA) based on satellite measurements. Satellite data include the Enhanced Vegetation Index (EVI) from the Moderate Resolution Imagining Spectroradiometer (MODIS) and the surface radiation budget from the International Satellite Cloud Climatology Project (ISCCP) for the period (2000-2004). The empirical model was calibrated (2 sites) and validated (6 sites) using observational measurements in the BLA. Results from F-test and t-student test have shown that observed and calculated ET have the same variance and mean values, respectively.

  4. Shuttle imaging radar A analysis of land use in Amazonia

    NASA Technical Reports Server (NTRS)

    Stone, Thomas A.; Woodwell, George M.

    1988-01-01

    Over large areas in the tropics, satellite imagery is the principal source of data on the area, current stature, and extent of disturbance of the forests. The information from imagery that covers large areas at low resolution is greatly enhanced when different types of imagery can be compared. The paper presents a comparison of data from Landsat MSS and from the Shuttle Imaging Radar (SIR-A) L band HH polarization data for sites in the Amazon Basin. Results indicate that SIR-A backscatter from the undisturbed forest was lower than that from some disturbed areas and from flooded forests and that SIR-A brightness, increases nonlinearly with the Landsat normalized difference vegetation index. It is hypothesized that the brightest radar returns in southern Amazonia are from newly cleared forests that are littered with standing and fallen tree boles that function as corner reflectors; and that backscatter will diminish from disturbed areas over time as fields are burned repeatedly.

  5. Fire-probability maps for the Brazilian Amazonia

    NASA Astrophysics Data System (ADS)

    Cardoso, Manoel; Sampaio, Gilvan; Obregon, Guillermo; Nobre, Carlos

    2010-05-01

    Most fires in Amazonia result from the combination between climate and land-use factors. They occur mainly in the dry season and are used as an inexpensive tool for land clearing and management. However, their unintended consequences are of important concern. Fire emissions are the most important sources of greenhouse gases and aerosols in the region, accidental fires are a major threat to protected areas, and frequent fires may lead to permanent conversion of forest areas into savannas. Fire-activity models have thus become important tools for environmental analyses in Amazonia. They are used, for example, in warning systems for monitoring the risk of burnings in protected areas, to improve the description of biogeochemical cycles and vegetation composition in ecosystem models, and to help estimate the long-term potential for savannas in biome models. Previous modeling studies for the whole region were produced in units of satellite fire pixels, which complicate their direct use for environmental applications. By reinterpreting remote-sensing based data using a statistical approach, we were able to calibrate models for the whole region in units of probability, or chance of fires to occur. The application of these models for years 2005 and 2006 provided maps of fire potential at 3-month and 0.25-deg resolution as a function of precipitation and distance from main roads. In both years, the performance of the resulting maps was better for the period July-September. During these months, most of satellite-based fire observations were located in areas with relatively high chance of fire, as determined by the modeled probability maps. In addition to reproduce reasonably well the areas presenting maximum fire activity as detected by remote sensing, the new results in units of probability are easier to apply than previous estimates from fire-pixel models.

  6. Fire-probability maps for the Brazilian Amazonia

    NASA Astrophysics Data System (ADS)

    Cardoso, M.; Nobre, C.; Obregon, G.; Sampaio, G.

    2009-04-01

    Most fires in Amazonia result from the combination between climate and land-use factors. They occur mainly in the dry season and are used as an inexpensive tool for land clearing and management. However, their unintended consequences are of important concern. Fire emissions are the most important sources of greenhouse gases and aerosols in the region, accidental fires are a major threat to protected areas, and frequent fires may lead to permanent conversion of forest areas into savannas. Fire-activity models have thus become important tools for environmental analyses in Amazonia. They are used, for example, in warning systems for monitoring the risk of burnings in protected areas, to improve the description of biogeochemical cycles and vegetation composition in ecosystem models, and to help estimate the long-term potential for savannas in biome models. Previous modeling studies for the whole region were produced in units of satellite fire pixels, which complicate their direct use for environmental applications. By reinterpreting remote-sensing based data using a statistical approach, we were able to calibrate models for the whole region in units of probability, or chance of fires to occur. The application of these models for years 2005 and 2006 provided maps of fire potential at 3-month and 0.25-deg resolution as a function of precipitation and distance from main roads. In both years, the performance of the resulting maps was better for the period July-September. During these months, most of satellite-based fire observations were located in areas with relatively high chance of fire, as determined by the modeled probability maps. In addition to reproduce reasonably well the areas presenting maximum fire activity as detected by remote sensing, the new results in units of probability are easier to apply than previous estimates from fire-pixel models.

  7. Marine intervals in Neogene fluvial deposits of western Amazonia

    NASA Astrophysics Data System (ADS)

    Boonstra, Melanie; Troelstra, Simon; Lammertsma, Emmy; Hoorn, Carina

    2014-05-01

    Amazonia is one of the most species rich areas on Earth, but this high diversity is not homogeneous over the entire region. Highest mammal and tree-alpha diversity is found in the fluvio-lacustrine Pebas system, a Neogene wetland associated with rapid radiation of species. The estuarine to marine origin of various modern Amazonian fish, plants, and invertebrates has been associated with past marine ingressions into this freshwater Pebas system. The exact nature and age of these invasions is, however, debated. Here we present new evidence from fluvial and fluvio-lacustrine deposits of Neogene age in southeast Colombia, that point to periods of widespread marine conditions in western Amazonia. Our evidence is based on an analysis of marine palynomorphs, such as organic linings of foraminifera and dinoflagellate cysts, present in dark sandy clay sediments that outcrop along the Caqueta and Amazon rivers. Characteristically, the foraminiferal linings can be assigned to three benthic morphotypes only, e.g. Ammonia, Elphidium and Trochammina. This low diversity assemblage is associated with estuarine/marginal marine conditions. No distinct marine elements such as shelf or planktonic species were encountered. The observed foraminiferal linings and dinocyst assemblages are typical for a (eutrophic) shallow marine environment, suggesting that the Pebas freshwater wetland system occasionally changed to (marginal) marine. Although some reworked elements are found, a typical Neogene dinocyst taxon is commonly found supporting in situ deposition. Sedimentological features typical for tidal conditions that are reported for sites in Peru and northeastern Brazil likely relate to these marine ingressions. Sea level changes as well as foreland basin development related to Andes formation may have facilitated the entry of marine water during the Neogene.

  8. Two hundred years of local avian extinctions in eastern Amazonia.

    PubMed

    Moura, Nárgila G; Lees, Alexander C; Aleixo, Alexandre; Barlow, Jos; Dantas, Sidnei M; Ferreira, Joice; Lima, Maria de Fátima C; Gardner, Toby A

    2014-10-01

    Local, regional, and global extinctions caused by habitat loss, degradation, and fragmentation have been widely reported for the tropics. The patterns and drivers of this loss of species are now increasingly well known in Amazonia, but there remains a significant gap in understanding of long-term trends in species persistence and extinction in anthropogenic landscapes. Such a historical perspective is critical for understanding the status and trends of extant biodiversity as well as for identifying priorities to halt further losses. Using extensive historical data sets of specimen records and results of contemporary surveys, we searched for evidence of local extinctions of a terra firma rainforest avifauna over 200 years in a 2500 km(2) eastern Amazonian region around the Brazilian city of Belém. This region has the longest history of ornithological fieldwork in the entire Amazon basin and lies in the highly threatened Belém Centre of Endemism. We also compared our historically inferred extinction events with extensive data on species occurrences in a sample of catchments in a nearby municipality (Paragominas) that encompass a gradient of past forest loss. We found evidence for the possible extinction of 47 species (14% of the regional species pool) that were unreported from 1980 to 2013 (80% last recorded between 1900 and 1980). Seventeen species appear on the International Union for Conservation of Nature Red List, and many of these are large-bodied. The species lost from the region immediately around Belém are similar to those which are currently restricted to well-forested catchments in Paragominas. Although we anticipate the future rediscovery or recolonization of some species inferred to be extinct by our calculations, we also expect that there are likely to be additional local extinctions, not reported here, given the ongoing loss and degradation of remaining areas of native vegetation across eastern Amazonia.

  9. Changes in radiative forcing in Amazonia: the influence of clouds and aerosols controlling carbon budget

    NASA Astrophysics Data System (ADS)

    Artaxo, Paulo

    2016-07-01

    Surface radiation fluxes are critically important in photosynthetic processes that controls carbon assimilation and losses in tropical forests. Clouds and aerosols control the surface radiation fluxes in Amazonia, and the ratio of diffuse and direct radiation directly affects photosynthetic plant processes. Biomass burning emissions changes the atmosphere aerosol loading. The background aerosol optical thickness in wet season Amazonia is about 0.1 at 550 nm, while during the dry season AOT can reach values as high as 3-4 over large areas. The increase in diffuse radiation significantly enhance photosynthesis. Remote sensing measurements using MODIS and AERONET were used to measure the large scale aerosol distribution over Amazonia, and LBA flux towers provided the carbon balance over several sites. The enhancement in carbon uptake for AOD between 0.1 and 1 can reach 45%. For AOD above 1, the reduction in the direct flux starts to dominate and a strong reduction in carbon uptake is observed. Cloud cover also has a huge impact on carbon balance in Amazonia, but it is more difficult to quantify. These effects controls carbon balance in Amazonia.

  10. Impact of biomass burning aerosol on the monsoon circulation transition over Amazonia

    SciTech Connect

    Zhang, Y.; Fu, Rong; Yu, Hongbin; Qian, Yun; Dickinson, Robert; Silva Dias, Maria Assuncao F.; da Silva Dias, Pedro L.; Fernandes, Katia

    2009-05-30

    Ensemble simulations of a regional climate model (RegCM3) forced by aerosol radiative forcing suggest that biomass burning aerosols can work against the seasonal monsoon circulation transition, thus re-enforce the dry season rainfall pattern for Southern Amazonia. Strongly absorbing smoke aerosols warm and stabilize the lower troposphere within the smoke center in southern Amazonia (where aerosol optical depth > 0.3). These changes increase the surface pressure in the smoke center, weaken the southward surface pressure gradient between northern and southern Amazonia, and consequently induce an anomalous moisture divergence in the smoke center and an anomalous convergence occurs in northwestern Amazonia (5°S-5°N, 60°W-40 70°W). The increased atmospheric thermodynamic stability, surface pressure, and divergent flow in Southern Amazonia may inhibit synoptic cyclonic activities propagated from extratropical South America, and re-enforce winter-like synoptic cyclonic activities and rainfall in southeastern Brazil, Paraguay and northeastern Argentina.

  11. Workplan for Catalyzing Collaboration with Amazonian Universities in the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA)

    NASA Technical Reports Server (NTRS)

    Brown, I. Foster; Moreira, Adriana

    1997-01-01

    Success of the Large-Scale Biosphere-Atmospheric Experiment in Amazonia (LBA) program depends on several critical factors, the most important being the effective participation of Amazonian researchers and institutions. Without host-county counterparts, particularly in Amazonia, many important studies cannot he undertaken due either to lack of qualified persons or to legal constraints. No less important, the acceptance of the LBA program in Amazonia is also dependent on what LBA can do for improving the scientific expertise in Amazonia. Gaining the active investment of Amazonian scientists in a comprehensive research program is not a trivial task. Potential collaborators are few, particularly where much of the research was to be originally focused - the southern arc of Brazilian Amazonia. The mid-term goals of the LBA Committee on Training and Education are to increase the number of collaborators and to demonstrate that LBA will be of benefit to the region.

  12. Arcella peruviana sp. nov. (Amoebozoa: Arcellinida, Arcellidae), a new species from a tropical peatland in Amazonia.

    PubMed

    Reczuga, Monika K; Swindles, Graeme T; Grewling, Łukasz; Lamentowicz, Mariusz

    2015-10-01

    There has only been one study on the ecology of testate amoebae from Amazonian peatlands, despite Amazonia being a biodiversity hotspot of global importance. During analysis of litter samples from Aucayacu peatland, western (Peruvian) Amazonia, we discovered a testate amoeba with a distinct morphology unlike any other species reported previously. We describe a new species, Arcella peruviana, based on its distinct morphology, compare it to morphologically similar species and provide information about its ecology. This new species is characterised by a distinct cruciform aperture (diameter ranges between 12 and 17μm) which is slightly invaginated. The test is small (height 43-57μm) and polygonal in cross-section. Our discovery suggests the existence of an unknown diversity of testate amoebae in Amazonia. The absence of the new Arcella species in more intensively-sampled regions supports the view that protists have restricted distributions.

  13. Biodiversity below ground: probing the subterranean ant fauna of Amazonia.

    PubMed

    Ryder Wilkie, Kari T; Mertl, Amy L; Traniello, James F A

    2007-09-01

    Ants are abundant, diverse, and ecologically dominant in tropical forests. Subterranean ants in particular are thought to have a significant environmental impact, although difficulties associated with collecting ants underground and examining their ecology and behavior have limited research. In this paper, we present the results of a study of subterranean ant diversity in Amazonian Ecuador that employs a novel probe to facilitate the discovery of species inhabiting the soil horizon. Forty-seven species of ants in 19 genera, including new and apparently rare species, were collected in probes. Approximately 19% of the species collected at different depths in the soil were unique to probe samples. Analysis of similarity (ANOSIM) results showed that the species composition of ants collected with the probe was significantly different from samples collected using other techniques. Additionally, ANOSIM computations indicated the species assemblage of ants collected 12.5 cm below the surface was significantly different from those found at 25, 37.5, and 50 cm. Ant diversity and species accumulation rates decreased with increasing depth. There were no species unique to the lowest depths, suggesting that subterranean ants may not be distributed deep in the soil in Amazonia due to the high water table. The technique we describe could be used to gain new insights into the distribution and biology of subterranean ant species and other members of the species-rich soil invertebrate macrofauna.

  14. Geomorphological evidence of recent tilting in the Central Amazonia Region

    NASA Astrophysics Data System (ADS)

    Ibanez, Delano Menecucci; Riccomini, Claudio; de Miranda, Fernando Pellon

    2014-06-01

    Geomorphometric techniques applied to remote sensing data represent powerful tools as an aid for detecting terrain features produced by recent vertical crustal movements in a variety of landscapes. In this work, geomorphometric analysis of the Central Amazonia drainage network using Shuttle Radar Topography Mission (SRTM) data was carried out to determine surface water loading and tectonic influence on the development of the Uatumã and Urubu river basins since the Miocene. The main objective was to detect geomorphological domains of lateral stream migration and channel sinuosity changes that could indicate recent vertical crustal movement. To achieve this, the Transverse Topographic Symmetry Factor and Sinuosity Index were applied to analyze the study area drainage network. Comparison of the geomorphological domains with structural field data and records of seismicity suggests that they are influenced by subsurface fault reactivation, which coincides in space with faults mapped in outcrops that have activated since the Miocene. This interpretation is corroborated by the spatial correspondence between these faults with domain boundaries and shapes, by river sinuosity change when crossing these boundaries, and by a high concentration of seismic activity along one of these limits. The crustal movement caused by hydrological loading can also influence such geomorphological features. Such is the case of lateral stream migrations of a domain in the opposite sense to the Amazon River flow. This may be a consequence of the more pronounced expression of hydrological loading in the Negro and Solimões river confluence region.

  15. Deforestation and threats to the biodiversity of Amazonia.

    PubMed

    Vieira, I C G; Toledo, P M; Silva, J M C; Higuchi, H

    2008-11-01

    This is a review of the main factors currently perceived as threats to the biodiversity of Amazonia. Deforestation and the expansion of the agricultural frontier go hand in hand within the context of occupation and land use in the region, followed by a hasty process of industrialization since the 1950s and, more recently, by a nation-wide attempt to adapt Brazil to economic globalization. Intensive agriculture and cattle-raising, lack of territorial planning, the monoculture of certain crops often promoted by official agencies, and the introduction of exotic species by cultivation are some of the factors affecting Amazonian biodiversity. There are still large gaps in knowledge that need to be dealt with for a better understanding of the local ecosystems so as to allow their preservation, but such investigation is subjected to manifold hindrances by misinformation, disinformation and sheer ignorance from the legal authorities and influential media. Data available for select groups of organisms indicate that the magnitude of the loss and waste of natural resources associated with deforestation is staggering, with estimated numbers of lost birds and primates being over ten times that of such animals illegally commercialized around the world in one year. The challenges to be met for an eventual reversal of this situation demand more systematic and concerted studies, the consolidation of new and existing research groups, and a call for a halt to activities depleting the Amazonian rainforest.

  16. [Environmental sustainability and health indicators in the Legal Amazonia, Brazil].

    PubMed

    Freitas, Carlos Machado de; Giatti, Leandro Luiz

    2009-06-01

    One of the challenges for public health is to build systems of indicators that allow monitoring current conditions and trends in environmental and health sustainability. This article focuses on the Legal Amazonia macro-region, which has undergone profound socioeconomic, environmental, and health changes since the mid-20th century. The conceptual framework adopted here was the model entitled Driving Forces, Pressures, State, Exposure, Effects, and Action (DPSEEA) proposed by the World Health Organization and adopted for environmental health surveillance by the Brazilian Ministry of Health. The results show that numerous motor forces and pressures have contributed to the growth of the economy and the population, as well as to improvements in some traditional health indicators (a reduction in infant mortality and an increase in life expectancy), alongside major social and economic inequalities and heterogeneity in environmental health impacts. This same process has been accompanied by environmental changes that indicate an unsustainable development model for present and future generations, demanding comprehensive action by public health and environmental institutions.

  17. Environmental Controls of Soil Organic Carbon in Soils Across Amazonia

    NASA Astrophysics Data System (ADS)

    Quesada, Carlos Alberto; Paz, Claudia; Phillips, Oliver; Nonato Araujo Filho, Raimundo; Lloyd, Jon

    2015-04-01

    Amazonian forests store and cycle a significant amount of carbon on its soils and vegetation. Yet, Amazonian forests are now subject to strong environmental pressure from both land use and climate change. Some of the more dramatic model projections for the future of the Amazon predict a major change in precipitation followed by savanization of most currently forested areas, resulting in major carbon losses to the atmosphere. However, how soil carbon stocks will respond to climatic and land use changes depend largely on how soil carbon is stabilized. Amazonian soils are highly diverse, being very variable in their weathering levels and chemical and physical properties, and thus it is important to consider how the different soils of the Basin stabilize and store soil organic carbon (SOC). The wide variation in soil weathering levels present in Amazonia, suggests that soil groups with contrasting pedogenetic development should differ in their predominant mechanism of SOC stabilization. In this study we investigated the edaphic, mineralogical and climatic controls of SOC concentration in 147 pristine forest soils across nine different countries in Amazonia, encompassing 14 different WRB soil groups. Soil samples were collected in 1 ha permanent plots used for forest dynamics studies as part of the RAINFOR project. Only 0-30 cm deep averages are reported here. Soil samples were analyzed for carbon and nitrogen and for their chemical (exchangeable bases, phosphorus, pH) and physical properties, (particle size, bulk density) and mineralogy through standard selective dissolution techniques (Fe and Al oxides) and by semi-quantitative X-Ray diffraction. In Addition, selected soils from each soil group had SOC fractionated by physical and chemical techniques. Our results indicate that different stabilization mechanisms are responsible for SOC stabilization in Amazonian soils with contrasting pedogenetic level. Ferralsols and Acrisols were found to have uniform mineralogy

  18. Neotectonics, flooding patterns and landscape evolution in southern Amazonia

    NASA Astrophysics Data System (ADS)

    Lombardo, U.

    2014-07-01

    The paper examines the role of neotectonic activity in the evolution of the landscape in southern Amazonia during the Holocene. It uses both new and published data based on the analysis of remote sensing imagery and extensive field work in the Llanos de Moxos, Bolivian Amazon. The study of the region's modern and paleo rivers, ria lakes, paleosols and topography provides a strong case in favour of the thesis that the northern part of the Llanos de Moxos constitutes the southern margin of the Fitzcarrald arch and that it has experienced uplift during the Holocene. The paper assesses the extent and timing of the neotectonic activity in light of the new data and reconstructs the evolution of the landscape since the late Pleistocene. The evidence suggests that at least two uplift events took place: a first uplift in the late Pleistocene, which caused the formation of Lake Oceano, and a second uplift during the mid-Holocene, which formed Lake Rogaguado. These two uplifts appear to be linked to the knickpoints observed close to the towns of Guayaramerín and Puerto Siles respectively. The backwater effect due to these uplifts transformed the region's major rivers in seasonal ria lakes, causing the deposition of thick organic clay layers along the Beni, Mamoré and Madre de Dios river banks. I argue that neotectonic episodes could have dramatically changed the drainage of the Llanos, determining its flooding regime, soil properties and forest-savannah ecotone. These results stress the need for geomorphologists, paleoecologists and archaeologists to take into account neotectonics when reconstructing the region's past.

  19. Neotectonics, flooding patterns and landscape evolution in southern Amazonia

    NASA Astrophysics Data System (ADS)

    Lombardo, U.

    2014-12-01

    The paper examines the role of neotectonic activity in the evolution of the landscape in southern Amazonia during the Holocene. It uses both new and published data based on the analysis of remote sensing imagery and extensive field work in the Llanos de Moxos, Bolivian Amazon. The study of the region's modern and palaeorivers, ria lakes, palaeosols and topography provides a strong case in favour of the thesis that the northern part of the Llanos de Moxos constitutes the southern margin of the Fitzcarrald Arch and that it has experienced uplift during the Holocene. The paper assesses the extent and timing of the neotectonic activity in light of the new data and reconstructs the evolution of the landscape since the late Pleistocene. The evidence suggests that at least two uplift events took place: a first uplift in the late Pleistocene, which caused the formation of Lake Oceano, and a second uplift during the mid-Holocene, which formed Lake Rogaguado. These two uplifts appear to be linked to the knickpoints observed close to the towns of Guayaramerín and Puerto Siles respectively. The backwater effect due to these uplifts transformed the region's major rivers in seasonal ria lakes, causing the deposition of thick organic clay layers along the Beni, Mamoré and Madre de Dios river banks. I argue that neotectonic episodes could have dramatically changed the drainage of the Llanos de Moxos, determining its flooding regime, soil properties and forest-savannah ecotone. These results stress the need for geomorphologists, palaeo-ecologists and archaeologists to take into account neotectonics when reconstructing the region's past.

  20. After trees die: quantities and determinants of necromass across Amazonia

    NASA Astrophysics Data System (ADS)

    Chao, K.-J.; Phillips, O. L.; Baker, T. R.; Peacock, J.; Lopez-Gonzalez, G.; Vásquez Martínez, R.; Monteagudo, A.; Torres-Lezama, A.

    2009-08-01

    The Amazon basin, one of the most substantial biomass carbon pools on earth, is characterised by strong macroecological gradients in biomass, mortality rates, and wood density from west to east. These gradients could affect necromass stocks, but this has not yet been tested. This study aims to assess the stocks and determinants of necromass across Amazonian forests. Field-based and literature data were used to find relationships between necromass and possible determinants. Furthermore, a simple model was applied to estimate and extrapolate necromass stocks across terra firma Amazonian forests. In eight northwestern and three northeastern Amazonian permanent plots, volumes of coarse woody debris (≥10 cm diameter) were measured in the field and the density of each decay class was estimated. Forest structure and historical mortality data were used to determine the factors controlling necromass. Necromass is greater in forests with low stem mortality rates (northeast) rather than in forests with high stem mortality rates (northwest) (58.5±10.6 and 27.3±3.2 Mg ha-1, respectively). Using all published necromass values, we find that necromass across terra firma forests in Amazonia is positively related to both forest dynamics (mortality mass inputs and a surrogate for decomposition rate (average wood density of living trees)) and forest structure (biomass), but is better explained by forest dynamics. We propose an improved method to estimate necromass for plots where necromass has not been measured. The estimates, together with other actual measurements of necromass, were scaled-up to project a total Amazonian necromass of 9.6±1.0 Pg C. The ratio of necromass (on average weighted by forest region) to coarse aboveground biomass is 0.127. Overall, we find (1) a strong spatial trend in necromass in parallel with other macroecological gradients and (2) that necromass is a substantial component of the carbon pool in the Amazon.

  1. Carbon storage in Amazonia during the last glacial maximum: secondary data and uncertainties.

    PubMed

    Turcq, Bruno; Cordeiro, Renato C; Sifeddine, Abdefettah; Simões Filho, Francisco F L; Albuquerque, Ana Luisa S; Abrão, Jorge J

    2002-12-01

    The Amazonian forest is, due to its great size, carbon storage capacity and present-day variability in carbon uptake and release, an important component of the global carbon cycle. Paleo-environmental reconstruction is difficult for Amazonia due to the scarcity of primary palynological data and the mis-interpretation of some secondary data. Studies of lacustrine sediment records have shown that Amazonia has known periods in which the climate was drier than it is today. However, not all geomorphological features such as dunes, and slope erosion, which are thought to indicate rainforest regression, date from the time of the Late Glacial Maximum (LGM) and these features do not necessarily correspond to episodes of forest regression. There is also uncertainty concerning LGM carbon storage due to rainforest soils and biomass estimates. Soil carbon content may decrease moderately during the LGM, whereas rainforest biomass may change considerably in response to changes in the global environment. Biomass per unit area in Amazonia has probably been reduced by the cumulative effects of low CO2 concentration, a drier climate and lower temperatures. As few paleo-vegetation data are available, there is considerable uncertainty concerning the amount of carbon stored in Amazonia during the LGM, which may have corresponded to 44-94% of the carbon currently stored in biomass and soils.

  2. Crommelin’s and Davidson’s visit to Amazonia and the 1919 total solar eclipse

    NASA Astrophysics Data System (ADS)

    de Lima, Marcelo C.; Crispino, Luís C. B.

    2016-04-01

    We report the visit to Amazonia of the British astronomers Crommelin and Davidson, in their way to the Brazilian city Sobral to perform the measurements related to the total solar eclipse of 29th May 1919, as an experimental test of the Theory of General Relativity.

  3. Contrasting andean geodynamics drive evolution of lowland taxa in western Amazonia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a palm lineage of 15 species (Astrocaryum sect. Huicungo), we tested an hypothesis that past geologic events in western Amazonia influenced the modern configuration of the upper Amazon drainage and thus diversification and distribution of these palsm, which found only in this region. The chang...

  4. The Pleasures and Pitfalls of a "Participatory" Documentation Project: An Experience in Northwestern Amazonia

    ERIC Educational Resources Information Center

    Stenzel, Kristine

    2014-01-01

    This article adds a voice from Amazonia to the reflective discussion on documentation projects designed within a "participatory" or "collaborative" paradigm of language research. It offers a critical assessment of one such documentation project carried out from 2007-2011 with the Kotiria and Wa'ikhana (East Tukano) language…

  5. Mapping landscape scale variations of forest structure, biomass, and productivity in Amazonia

    NASA Astrophysics Data System (ADS)

    Saatchi, S.; Malhi, Y.; Zutta, B.; Buermann, W.; Anderson, L. O.; Araujo, A. M.; Phillips, O. L.; Peacock, J.; Ter Steege, H.; Lopez Gonzalez, G.; Baker, T.; Arroyo, L.; Almeida, S.; Higuchi, N.; Killeen, T.; Monteagudo, A.; Neill, D.; Pitman, N.; Prieto, A.; Salomão, R.; Silva, N.; Vásquez Martínez, R.; Laurance, W.; Ramírez, H. A.

    2009-06-01

    Landscape and environmental variables such as topography, geomorphology, soil types, and climate are important factors affecting forest composition, structure, productivity, and biomass. Here, we combine a network of forest inventories with recently developed global data products from satellite observations in modeling the potential distributions of forest structure and productivity in Amazonia and examine how geomorphology, soil, and precipitation control these distributions. We use the RAINFOR network of forest plots distributed in lowland forests across Amazonia, and satellite observations of tree cover, leaf area index, phenology, moisture, and topographical variations. A maximum entropy estimation (Maxent) model is employed to predict the spatial distribution of several key forest structure parameters: basal area, fraction of large trees, fraction of palms, wood density, productivity, and above-ground biomass at 5 km spatial resolution. A series of statistical tests at selected thresholds as well as across all thresholds and jackknife analysis are used to examine the accuracy of distribution maps and the relative contributions of environmental variables. The final maps were interpreted using soil, precipitation, and geomorphological features of Amazonia and it was found that the length of dry season played a key role in impacting the distribution of all forest variables except the wood density. Soil type had a significant impact on the wood productivity. Most high productivity forests were distributed either on less infertile soils of western Amazonia and Andean foothills, on crystalline shields, and younger alluvial deposits. Areas of low elevation and high density of small rivers of Central Amazonia showed distinct features, hosting mainly forests with low productivity and smaller trees.

  6. Time Resolved Measurements of Primary Biogenic Aerosol Particles in Amazonia

    NASA Astrophysics Data System (ADS)

    Wollny, A. G.; Garland, R.; Pöschl, U.

    2009-04-01

    Biogenic aerosols are ubiquitous in the Earth's atmosphere and they influence atmospheric chemistry and physics, the biosphere, climate, and public health. They play an important role in the spread of biological organisms and reproductive materials, and they can cause or enhance human, animal, and plant diseases. Moreover, they influence the Earth's energy budget by scattering and absorbing radiation, and they can initiate the formation of clouds and precipitation as cloud condensation and ice nuclei. The composition, abundance, and origin of biogenic aerosol particles and components are, however, still not well understood and poorly quantified. Prominent examples of primary biogenic aerosol particles, which are directly emitted from the biosphere to the atmosphere, are pollen, bacteria, fungal spores, viruses, and fragments of animals and plants. During the Amazonian Aerosol Characterization Experiment (AMAZE-08) a large number of aerosol and gas-phase measurements were taken on a remote site close to Manaus, Brazil, during a period of five weeks in February and March 2008. This presented study is focused on data from an ultraviolet aerodynamic particle sizer (UVAPS, TSI inc.) that has been deployed for the first time in Amazonia. In this instrument, particle counting and aerodynamic sizing over the range of 0.5-20 µm are complemented by the measurement of UV fluorescence at 355 nm (excitation) and 420-575 nm (emission), respectively. Fluorescence at these wavelengths is characteristic for reduced pyridine nucleotides (e.g., NAD(P)H) and for riboflavin, which are specific for living cells. Thus particles exhibiting fluorescence signals can be regarded as "viable aerosols" or "fluorescent bioparticles" (FBAP), and their concentration can be considered as lower limit for the actual abundance of primary biogenic aerosol particles. Data from the UVAPS were averaged over 5 minute time intervals. The presence of bioparticles in the observed size range has been

  7. Long term aerosol and trace gas measurements in Central Amazonia

    NASA Astrophysics Data System (ADS)

    Artaxo, Paulo; Barbosa, Henrique M. J.; Ferreira de Brito, Joel; Carbone, Samara; Rizzo, Luciana V.; Andreae, Meinrat O.; Martin, Scot T.

    2016-04-01

    The central region of the Amazonian forest is a pristine region in terms of aerosol and trace gases concentrations. In the wet season, Amazonia is actually one of the cleanest continental region we can observe on Earth. A long term observational program started 20 years ago, and show important features of this pristine region. Several sites were used, between then ATTO (Amazon Tall Tower Observatory) and ZF2 ecological research site, both 70-150 Km North of Manaus, receiving air masses that traveled over 1500 km of pristine tropical forests. The sites are GAW regional monitoring stations. Aerosol chemical composition (OC/EC and trace elements) is being analysed using filters for fine (PM2.5) and coarse mode aerosol as well as Aerodyne ACSM (Aerosol Chemical Speciation Monitors). VOCs are measured using PTR-MS, while CO, O3 and CO2 are routinely measured. Aerosol absorption is being studied with AE33 aethalometers and MAAP (Multi Angle Absorption Photometers). Aerosol light scattering are being measured at several wavelengths using TSI and Ecotech nephelometers. Aerosol size distribution is determined using scanning mobility particle sizer at each site. Lidars measure the aerosol column up to 12 Km providing the vertical profile of aerosol extinction. The aerosol column is measures using AERONET sun photometers. In the wet season, organic aerosol comprises 75-85% of fine aerosol, and sulfate and nitrate concentrations are very low (1-3 percent). Aerosols are dominated by biogenic primary particles as well as SOA from biogenic precursors. Black carbon in the wet season accounts for 5-9% of fine mode aerosol. Ozone in the wet season peaks at 10-12 ppb at the middle of the day, while carbon monoxide averages at 50-80 ppb. Aerosol optical thickness (AOT) is a low 0.05 to 0.1 at 550 nm in the wet season. Sahara dust transport events sporadically enhance the concentration of soil dust aerosols and black carbon. In the dry season (August-December), long range transported

  8. Impact of Biomass Burning Aerosols on the Biosphere over Amazonia

    NASA Astrophysics Data System (ADS)

    Malavelle, F.; Haywood, J.; Mercado, L.; Folberth, G.; Bellouin, N.

    2014-12-01

    Biomass burning (BB) smoke from deforestation and the burning of agricultural waste emit a complex cocktail of aerosol particles and gases. BB emissions show a regional hotspot over South America on the edges of Amazonia. These major perturbations and impacts on surface temperature, surface fluxes, chemistry, radiation, rainfall, may have significant consequent impacts on the Amazon rainforest, the largest and most productive carbon store on the planet. There is therefore potential for very significant interaction and interplay between aerosols, clouds, radiation and the biosphere in the region. Terrestrial carbon production (i.e. photosynthesis) is intimately tied to the supply of photosynthetically active radiation (PAR - i.e. wavelengths between 300-690 nm). PAR in sufficient intensity and duration is critical for plant growth. However, if a decrease in total radiation is accompanied by an increase in the component of diffuse radiation, plant productivity may increase due to higher light use efficiency per unit of PAR and less photosynthetic saturation. This effect, sometimes referred as diffuse light fertilization effect, could have increased the global land carbon sink by approximately one quarter during the global dimming period and is expected to be a least as important locally. By directly interacting with radiation, BB aerosols significantly reduce the total amount of PAR available to plant canopies. In addition, BB aerosols also play a centre role in cloud formation because they provide the necessary cloud condensation nuclei, hence indirectly altering the water cycle and the components and quantity of PAR. In this presentation, we use the recent observations from the South American Biomass Burning Analysis (SAMBBA) to explore the impact of radiation changes on the carbon cycle in the Amazon region caused by BB emissions. A parameterisation of the impact of diffuse and direct radiation upon photosynthesis rates and net primary productivity in the

  9. Continuous soil carbon storage of old permanent pastures in Amazonia.

    PubMed

    Stahl, Clément; Fontaine, Sébastien; Klumpp, Katja; Picon-Cochard, Catherine; Grise, Marcia Mascarenhas; Dezécache, Camille; Ponchant, Lise; Freycon, Vincent; Blanc, Lilian; Bonal, Damien; Burban, Benoit; Soussana, Jean-François; Blanfort, Vincent

    2016-12-14

    Amazonian forests continuously accumulate carbon (C) in biomass and in soil, representing a carbon sink of 0.42-0.65 GtC yr(-1) . In recent decades, more than 15% of Amazonian forests have been converted into pastures, resulting in net C emissions (~200 tC ha(-1) ) due to biomass burning and litter mineralization in the first years after deforestation. However, little is known about the capacity of tropical pastures to restore a C sink. Our study shows in French Amazonia that the C storage observed in native forest can be partly restored in old (≥24 year) tropical pastures managed with a low stocking rate (±1 LSU ha(-1) ) and without the use of fire since their establishment. A unique combination of a large chronosequence study and eddy covariance measurements showed that pastures stored between -1.27 ± 0.37 and -5.31 ± 2.08 tC ha(-1)  yr(-1) while the nearby native forest stored -3.31 ± 0.44 tC ha(-1)  yr(-1) . This carbon is mainly sequestered in the humus of deep soil layers (20-100 cm), whereas no C storage was observed in the 0- to 20-cm layer. C storage in C4 tropical pasture is associated with the installation and development of C3 species, which increase either the input of N to the ecosystem or the C:N ratio of soil organic matter. Efforts to curb deforestation remain an obvious priority to preserve forest C stocks and biodiversity. However, our results show that if sustainable management is applied in tropical pastures coming from deforestation (avoiding fires and overgrazing, using a grazing rotation plan and a mixture of C3 and C4 species), they can ensure a continuous C storage, thereby adding to the current C sink of Amazonian forests.

  10. Characterizing patterns of agricultural land use in Amazonia by merging satellite imagery and census data

    NASA Astrophysics Data System (ADS)

    Cardille, Jeffrey Alan

    In recent decades, millions of hectares of Amazonian primary forest, cerrado, and secondary forest have been cleared to support a dramatically increasing number of cattle and humans. With plans proposed for major new highways and utilities in the basin, development is highly likely to continue in coming years. Conversion to human use threatens to change the climate, ecosystems, and natural resources of Amazonia, and these effects are due not only to changes in land cover but to the land use management practices that follow. Unfortunately, we lack basin-wide information about land use across Amazonia. A key reason for this dearth of information is that earth-observing satellites designed to interpret land cover are prone to miss the land use changes within; in an area encompassing millions of square kilometers, it is impossible to visit more than a small portion of the study region to quantify land use activities. Agricultural censuses suggest a strategy to fill this gap: in Amazonia, they provide the only ground-surveyed land use information---yet because they are not easily reconciled with satellite-based land cover information, census data are underutilized. The research forming this dissertation presents a new, basin-wide depiction of land use in Amazonia by developing and applying new tools for understanding the past, current, and future impact of agricultural development. Specifically, this dissertation: (1) presents a new detailed understanding of the distribution and density of agricultural land use practices in Amazonia in the mid-1990s by fusing agricultural census data with satellite-derived land cover classifications; (2) assesses historical changes in agriculture of the previous decades; and (3) describes and applies new general techniques for the rapid update of land use data sets and maps using satellite imagery and census data. The fusion of census and satellite data described here advances our understanding by uniting the strengths of two distinct

  11. Soil and vegetation carbon stocks in Brazilian Western Amazonia: relationships and ecological implications for natural landscapes.

    PubMed

    Schaefer, C E G R; do Amaral, E F; de Mendonça, B A F; Oliveira, H; Lani, J L; Costa, L M; Fernandes Filho, E I

    2008-05-01

    The relationships between soils attributes, soil carbon stocks and vegetation carbon stocks are poorly know in Amazonia, even at regional scale. In this paper, we used the large and reliable soil database from Western Amazonia obtained from the RADAMBRASIL project and recent estimates of vegetation biomass to investigate some environmental relationships, quantifying C stocks of intact ecosystem in Western Amazonia. The results allowed separating the western Amazonia into 6 sectors, called pedo-zones: Roraima, Rio Negro Basin, Tertiary Plateaux of the Amazon, Javari-Juruá-Purus lowland, Acre Basin and Rondonia uplands. The highest C stock for the whole soil is observed in the Acre and in the Rio Negro sectors. In the former, this is due to the high nutrient status and high clay activity, whereas in the latter, it is attributed to a downward carbon movement attributed to widespread podzolization and arenization, forming spodic horizons. The youthful nature of shallow soils of the Javari-Juruá-Purus lowlands, associated with high Al, results in a high phytomass C/soil C ratio. A similar trend was observed for the shallow soils from the Roraima and Rondonia highlands. A consistent east-west decline in biomass carbon in the Rio Negro Basin sector is associated with increasing rainfall and higher sand amounts. It is related to lesser C protection and greater C loss of sandy soils, subjected to active chemical leaching and widespread podzolization. Also, these soils possess lower cation exchangeable capacity and lower water retention capacity. Zones where deeply weathered Latosols dominate have a overall pattern of high C sequestration, and greater than the shallower soils from the upper Amazon, west of Madeira and Negro rivers. This was attributed to deeper incorporation of carbon in these clayey and highly pedo-bioturbated soils. The results highlight the urgent need for refining soil data at an appropriate scale for C stocks calculations purposes in Amazonia. There

  12. Pharmacists' Satisfaction with Their Pharmacy Education: Were They Prepared for OBRA-90?

    ERIC Educational Resources Information Center

    Arocho, Raul; And Others

    1995-01-01

    A survey of 303 graduates of 7 pharmacy schools investigated graduates' preparation for compliance with Omnibus Budget Reconciliation Act 1990 (OBRA-90) which mandated patient counseling and prospective drug utilization review. Results showed general satisfaction with students' preparation for OBRA-90 requirements. Respondents expressed most…

  13. Edaphic and light conditions of sympatric plant morphotypes in western Amazonia

    PubMed Central

    2014-01-01

    Abstract Here I present a dataset of edaphic and light conditions associated with the occurrence of sympatric morphotypes of Geonoma macrostachys (Arecaceae/Palmae), a candidate case study from Amazonia hypothesized to have evolved under ecological speciation. Transects were established in three lowland rainforests in Peru, and the abundance of each local morphotype of this species was recorded in a total area of 4.95 hectares. Composite soil samples and hemispherical photographs were taken along the transects were the species occurred to obtain information on soil nutrients, soil texture, and indirect measurements of light availability. The raw and summary tables disclose the characteristics of each study site and habitats within them, which could be useful to soil scientists, ecologists, and conservationists engaged in similar research activities or meta-analyses in Amazonia. PMID:24891831

  14. Holocene fire and occupation in Amazonia: records from two lake districts.

    PubMed

    Bush, Mark B; Silman, Miles R; de Toledo, Mauro B; Listopad, Claudia; Gosling, William D; Williams, Christopher; de Oliveira, Paulo E; Krisel, Carolyn

    2007-02-28

    While large-scale pre-Columbian human occupation and ecological disturbance have been demonstrated close to major Amazonian waterways, less is known of sites in terra firme settings. Palaeoecological analyses of two lake districts in central and western Amazonia reveal long histories of occupation and land use. At both locations, human activity was centred on one of the lakes, while the others were either lightly used or unused. These analyses indicate that the scale of human impacts in these terra firme settings is localized and probably strongly influenced by the presence of a permanent open-water body. Evidence is found of forest clearance and cultivation of maize and manioc. These data are directly relevant to the resilience of Amazonian conservation, as they do not support the contention that all of Amazonia is a 'built landscape' and therefore a product of past human land use.

  15. Edaphic and light conditions of sympatric plant morphotypes in western Amazonia.

    PubMed

    Roncal, Julissa

    2014-01-01

    Here I present a dataset of edaphic and light conditions associated with the occurrence of sympatric morphotypes of Geonomamacrostachys (Arecaceae/Palmae), a candidate case study from Amazonia hypothesized to have evolved under ecological speciation. Transects were established in three lowland rainforests in Peru, and the abundance of each local morphotype of this species was recorded in a total area of 4.95 hectares. Composite soil samples and hemispherical photographs were taken along the transects were the species occurred to obtain information on soil nutrients, soil texture, and indirect measurements of light availability. The raw and summary tables disclose the characteristics of each study site and habitats within them, which could be useful to soil scientists, ecologists, and conservationists engaged in similar research activities or meta-analyses in Amazonia.

  16. Reconstructing habitats in central Amazonia using megafauna, sedimentology, radiocarbon, and isotope analyses

    NASA Astrophysics Data System (ADS)

    de Fátima Rossetti, Dilce; de Toledo, Peter Mann; Moraes-Santos, Heloísa Maria; de Araújo Santos, Antônio Emídio

    2004-05-01

    A paleomegafauna site from central Amazonia with exceptional preservation of mastodons and ground sloths allows for the first time a precise age control based on 14C analysis, which, together with sedimentological and δ 13C isotope data, provided the basis to discuss habitat evolution within the context of climate change during the past 15,000 yr. The fossil-bearing deposits, trapped within a depression in the Paleozoic basement, record three episodes of sedimentation formed on floodplains, with an intermediate unit recording a catastrophic deposition through debris flows, probably favored during fast floodings. The integrated approach presented herein supports a change in humidity in central Amazonia through the past 15,000 yr, with a shift from drier to arboreal savanna at 11,340 (±50) 14C yr B.P. and then to a dense forest like we see today at 4620 (±60) 14C yr B.P.

  17. Amazonia through time: Andean uplift, climate change, landscape evolution, and biodiversity.

    PubMed

    Hoorn, C; Wesselingh, F P; ter Steege, H; Bermudez, M A; Mora, A; Sevink, J; Sanmartín, I; Sanchez-Meseguer, A; Anderson, C L; Figueiredo, J P; Jaramillo, C; Riff, D; Negri, F R; Hooghiemstra, H; Lundberg, J; Stadler, T; Särkinen, T; Antonelli, A

    2010-11-12

    The Amazonian rainforest is arguably the most species-rich terrestrial ecosystem in the world, yet the timing of the origin and evolutionary causes of this diversity are a matter of debate. We review the geologic and phylogenetic evidence from Amazonia and compare it with uplift records from the Andes. This uplift and its effect on regional climate fundamentally changed the Amazonian landscape by reconfiguring drainage patterns and creating a vast influx of sediments into the basin. On this "Andean" substrate, a region-wide edaphic mosaic developed that became extremely rich in species, particularly in Western Amazonia. We show that Andean uplift was crucial for the evolution of Amazonian landscapes and ecosystems, and that current biodiversity patterns are rooted deep in the pre-Quaternary.

  18. Satellite observation of tropical forest seasonality: spatial patterns of carbon exchange in Amazonia

    NASA Astrophysics Data System (ADS)

    Xu, Liang; Saatchi, Sassan S.; Yang, Yan; Myneni, Ranga B.; Frankenberg, Christian; Chowdhury, Diya; Bi, Jian

    2015-08-01

    Determining the seasonality of terrestrial carbon exchange with the atmosphere remains a challenge in tropical forests because of the heterogeneity of ecosystem and climate. The magnitude and spatial variability of this flux are unknown, particularly in Amazonia where empirical upscaling approaches from spatially sparse in situ measurements and simulations from process-based models have been challenged in recent scientific literature. Here, we use satellite proxy observations of canopy structure, skin temperature, water content, and optical properties over a period of 10 years (2000-2009) to constrain and quantify the spatial pattern and seasonality of carbon exchange of Amazonian forests. We identify nine regions through an optimized cluster approach with distinct leaf phenology synchronized with either water or light availability and corresponding seasonal cycles of gross primary production (GPP), covering more than 600 million ha of remaining old growth forests of Amazonia. We find South and Southwestern regions show strong seasonality of GPP with a peak in the wet season; while from Central Western to Northeastern Amazonia cover three regions with rising GPP in the dry season. The remaining four regions have significant but weak seasonality. These patterns agree with satellite florescence observations, a better proxy for photosynthetic activity. Our results suggest that only one-third of the patterns can be explained by the spatial autocorrelation caused by intra-annual variability of climate over Amazonia. The remaining two-thirds of variations are due to biogeography of the Amazon basin driven by forest composition, structure, and nutrients. These patterns, for the first time, provide a complex picture of seasonal changes of tropical forests related to photosynthesis and influenced by water, light, and stomatal responses of trees that can improve modeling of regional carbon cycle and future prediction of impacts of climate change.

  19. A new species of phlebotomine, Trichophoromyia adelsonsouzai (Diptera: Psychodidae) of Brazilian Amazonia

    PubMed Central

    dos Santos, Thiago Vasconcelos; da Silva, Fábio Márcio Medeiros; Barata, Iorlando da Rocha; de Andrade, Andrey José; Galati, Eunice Aparecida Bianchi

    2013-01-01

    The phlebotomine sandfly Trichophoromyia adelsonsouzai sp. nov. is described and illustrated based on the male and female morphological characteristics of specimens collected at Km 27 of the Trans-Amazonian Highway, municipality of Vitória do Xingu, state of Pará, Brazilian Amazonia. This is an area subject to the direct influence of Belo Monte hydroelectric system. With the description of this new species the number of Trichophoromyia sandflies recorded in Brazil is increased to 20. PMID:24141964

  20. A new species of phlebotomine, Trichophoromyia adelsonsouzai (Diptera: Psychodidae) of Brazilian Amazonia.

    PubMed

    Santos, Thiago Vasconcelos dos; Silva, Fábio Márcio Medeiros da; Barata, Iorlando da Rocha; Andrade, Andrey José de; Galati, Eunice Aparecida Bianchi

    2014-04-01

    The phlebotomine sandfly Trichophoromyia adelsonsouzai sp. nov. is described and illustrated based on the male and female morphological characteristics of specimens collected at Km 27 of the Trans-Amazonian Highway, municipality of Vitória do Xingu, state of Pará, Brazilian Amazonia. This is an area subject to the direct influence of Belo Monte hydroelectric system. With the description of this new species the number of Trichophoromyia sandflies recorded in Brazil is increased to 20.

  1. Campylobacter fetus Bacteremia in a Healthy Patient Returning from a Trip to the Ecuadorian Amazonia.

    PubMed

    Chávez, A C; Barrera, S; Leon, A; Trueba, G

    2016-12-27

    Campylobacter fetus is an opportunistic pathogen which causes bacteremia and other invasive infections in immunocompromised patients who have been exposed to livestock or ingested animal products (uncooked meat or unpasteurized milk). The present report describes a C. fetus infection in a healthy adult (immunocompetent) who returned from a visit to the Ecuadorian Amazonia and who did not report exposure to the typical sources of infection.

  2. Forest productivity and water stress in Amazonia: observations from GOSAT chlorophyll fluorescence.

    PubMed

    Lee, Jung-Eun; Frankenberg, Christian; van der Tol, Christiaan; Berry, Joseph A; Guanter, Luis; Boyce, C Kevin; Fisher, Joshua B; Morrow, Eric; Worden, John R; Asefi, Salvi; Badgley, Grayson; Saatchi, Sassan

    2013-06-22

    It is unclear to what extent seasonal water stress impacts on plant productivity over Amazonia. Using new Greenhouse gases Observing SATellite (GOSAT) satellite measurements of sun-induced chlorophyll fluorescence, we show that midday fluorescence varies with water availability, both of which decrease in the dry season over Amazonian regions with substantial dry season length, suggesting a parallel decrease in gross primary production (GPP). Using additional SeaWinds Scatterometer onboard QuikSCAT satellite measurements of canopy water content, we found a concomitant decrease in daily storage of canopy water content within branches and leaves during the dry season, supporting our conclusion. A large part (r(2) = 0.75) of the variance in observed monthly midday fluorescence from GOSAT is explained by water stress over moderately stressed evergreen forests over Amazonia, which is reproduced by model simulations that include a full physiological representation of photosynthesis and fluorescence. The strong relationship between GOSAT and model fluorescence (r(2) = 0.79) was obtained using a fixed leaf area index, indicating that GPP changes are more related to environmental conditions than chlorophyll contents. When the dry season extended to drought in 2010 over Amazonia, midday basin-wide GPP was reduced by 15 per cent compared with 2009.

  3. Hydro-climate and ecological behaviour of the drought of Amazonia in 2005.

    PubMed

    Marengo, J A; Nobre, C A; Tomasella, J; Cardoso, M F; Oyama, M D

    2008-05-27

    In 2005, southwestern Amazonia experienced the effects of an intense drought that affected life and biodiversity. Several major tributaries as well as parts of the main river itself contained only a fraction of their normal volumes of water, and lakes were drying up. The consequences for local people, animals and the forest itself are impossible to estimate now, but they are likely to be serious. The analyses indicate that the drought was manifested as weak peak river season during autumn to winter as a consequence of a weak summertime season in southwestern Amazonia; the winter season was also accompanied by rainfall that sometimes reached 25% of the climatic value, being anomalously warm and dry and helping in the propagation of fires. Analyses of climatic and hydrological records in Amazonia suggest a broad consensus that the 2005 drought was linked not to El Niño as with most previous droughts in the Amazon, but to warming sea surface temperatures in the tropical North Atlantic Ocean.

  4. Forest productivity and water stress in Amazonia: observations from GOSAT chlorophyll fluorescence

    PubMed Central

    Lee, Jung-Eun; Frankenberg, Christian; van der Tol, Christiaan; Berry, Joseph A.; Guanter, Luis; Boyce, C. Kevin; Fisher, Joshua B.; Morrow, Eric; Worden, John R.; Asefi, Salvi; Badgley, Grayson; Saatchi, Sassan

    2013-01-01

    It is unclear to what extent seasonal water stress impacts on plant productivity over Amazonia. Using new Greenhouse gases Observing SATellite (GOSAT) satellite measurements of sun-induced chlorophyll fluorescence, we show that midday fluorescence varies with water availability, both of which decrease in the dry season over Amazonian regions with substantial dry season length, suggesting a parallel decrease in gross primary production (GPP). Using additional SeaWinds Scatterometer onboard QuikSCAT satellite measurements of canopy water content, we found a concomitant decrease in daily storage of canopy water content within branches and leaves during the dry season, supporting our conclusion. A large part (r2 = 0.75) of the variance in observed monthly midday fluorescence from GOSAT is explained by water stress over moderately stressed evergreen forests over Amazonia, which is reproduced by model simulations that include a full physiological representation of photosynthesis and fluorescence. The strong relationship between GOSAT and model fluorescence (r2 = 0.79) was obtained using a fixed leaf area index, indicating that GPP changes are more related to environmental conditions than chlorophyll contents. When the dry season extended to drought in 2010 over Amazonia, midday basin-wide GPP was reduced by 15 per cent compared with 2009. PMID:23760636

  5. The influence of the land surface on the transition from dry to wet season in Amazonia

    NASA Astrophysics Data System (ADS)

    Fu, R.; Li, W.

    Analysis of the fifteen years of European Centre for Medium Range Weather Forecasts (ECMWF) reanalysis suggests that the transition from dry to wet season in Southern Amazonia is initially driven by increases of surface latent heat flux. These fluxes rapidly reduce Convective Inhibition Energy (CINE) and increase Convective Available Potential Energy (CAPE), consequently providing favourable conditions for increased rainfall even before the large-scale circulation has changed. The increase of rainfall presumably initiates the reversal of the cross-equatorial flow, leading to large-scale net moisture convergence over Southern Amazonia. An analysis of early and late wet season onsets on an interannual scale shows that a longer dry season with lower rainfall reduces surface latent heat flux in the dry and earlier transition periods compared to that of a normal wet season onset. These conditions result in a higher CINE and a lower CAPE, causing a delay in the increase of local rainfall in the initiating phase of the transition and consequently in the wet season onset. Conversely, a wetter dry season leads to a higher surface latent heat flux and weaker CINE, providing a necessary condition for an earlier increase of local rainfall and an earlier wet season onset. Our results imply that if land use change in Amazonia reduces rainfall during dry and transition seasons, it could significantly delay the wet season onset and prolong the dry season.

  6. [Deregulation and equity: the Obras Sociales reconversion process in Argentina].

    PubMed

    Findling, Liliana; Arrunada, María; Klimovsky, Ezequiel

    2002-01-01

    The health care services managed by trade unions and known as "Obras Sociales" form the groundwork for Argentina's Social Security and Health system. However, far from taking an equitable approach, these institutions highlight the country's prevailing income disparities, which in turn lead to major differences in access to care. The main focus of this study was the reformulation of social security health policies within the framework of deregulation from 1998 to 2000, analyzing the effects on availability of health care services from an equity perspective. The methodology used two related analytical levels: (1) a macro level viewing the process from the various players' strategies and (2) a micro level featuring the changes within a well-known trade union social security organization during its reconversion process, emphasizing its institutional scope and the opinions of its membership. The results thus pointed to the slow implementation of reforms initiated by the public sector, hindered by constant negotiations among the main corporate actors seeking to serve their particular interests, along with increased inequity and fragmentation due to the limited opening of free choice by members.

  7. There's no place like home: seedling mortality contributes to the habitat specialisation of tree species across Amazonia.

    PubMed

    Fortunel, Claire; Paine, C E Timothy; Fine, Paul V A; Mesones, Italo; Goret, Jean-Yves; Burban, Benoit; Cazal, Jocelyn; Baraloto, Christopher

    2016-10-01

    Understanding the mechanisms generating species distributions remains a challenge, especially in hyperdiverse tropical forests. We evaluated the role of rainfall variation, soil gradients and herbivory on seedling mortality, and how variation in seedling performance along these gradients contributes to habitat specialisation. In a 4-year experiment, replicated at the two extremes of the Amazon basin, we reciprocally transplanted 4638 tree seedlings of 41 habitat-specialist species from seven phylogenetic lineages among the three most important forest habitats of lowland Amazonia. Rainfall variation, flooding and soil gradients strongly influenced seedling mortality, whereas herbivory had negligible impact. Seedling mortality varied strongly among habitats, consistent with predictions for habitat specialists in most lineages. This suggests that seedling performance is a primary determinant of the habitat associations of adult trees across Amazonia. It further suggests that tree diversity, currently mostly harboured in terra firme forests, may be strongly impacted by the predicted climate changes in Amazonia.

  8. Amazonia Introduced to General Relativity: The May 29, 1919, Solar Eclipse from a North-Brazilian Point of View

    NASA Astrophysics Data System (ADS)

    Crispino, Luís C. B.; de Lima, Marcelo C.

    2016-12-01

    In 1919, A. C. D. Crommelin and C. R. Davidson, British astronomers from the Greenwich Observatory in England, passed by Amazonia on their Brazilian journey aiming to measure the bending of stars' light rays during the total solar eclipse of May 29, 1919, and thereby put the theory of general relativity to the test. In the context of Crommelin's and Davidson's visit, we discuss how Amazonia was introduced to Einstein's theory of gravitation, and also the observations and repercussions of the May 29, 1919, solar eclipse in Belém, capital city of the North-Brazilian Pará state.

  9. The Miocene Cyprideis species flock (Ostracoda; Crustacea) of western Amazonia (Solimões Formation)

    NASA Astrophysics Data System (ADS)

    Gross, Martin; Ramos, Maria Ines F.; Piller, Werner E.

    2015-04-01

    The Miocene mega-wetland of western Amazonia holds a diverse, largely endemic aquatic invertebrate fauna (e.g., molluscs, ostracods). Among ostracods, the genus Cyprideis experienced a remarkable radiation. Micropalaeontologic investigations of a 400-m-long sediment core (~62 km SW Benjamin Constant, Amazonia, Brazil) permitted a taxonomic revision of about two-thirds of hitherto described Cyprideis species. Ostracod index species enabled a biostratigraphic allocation of the well succession to the Cyprideis minipunctata to Cyprideis cyrtoma biozones (late middle to early late Miocene age). The current study underlines once more Cyprideis' remarkable capability to produce species flocks and western Amazonian Cyprideis comply with the criteria of a species flock: i) endemicity: up to now not a single species is recorded in adjacent areas; ii) monophyly: although hardly verifiable to date and probably Amazonian Cyprideis is not monophyletic s.str., several closely related, quite rapidly evolving species are proved; iii) speciosity: due to the present study, 30 formally described species exist; several further species, left in open nomenclature, are recorded in the literature, which strongly hints to a much higher, still unrecorded species richness; iv) ecological diversity: based on rare sedimentologic cross-references, ecological diversity within a highly structured wetland is possible; the current results demonstrate the sympatric occurrence of up to 12 Cyprideis species, which may indicate adaptations to different microhabitats; v) habitat dominance: regularly Cyprideis holds more than >90 % in western Amazonian ostracod assemblages during the early and middle Miocene. Explanations for this extreme habitat monopolisation are still arguable and touch the highly disputed question about the nature of western Amazonia's environments during the Miocene. It seems, however, evident that a strictly actualistic approach to endemic Neogene Amazonian biota is highly

  10. Environmental impact of geometric earthwork construction in pre-Columbian Amazonia

    PubMed Central

    Carson, John Francis; Whitney, Bronwen S.; Mayle, Francis E.; Iriarte, José; Prümers, Heiko; Soto, J. Daniel; Watling, Jennifer

    2014-01-01

    There is considerable controversy over whether pre-Columbian (pre-A.D. 1492) Amazonia was largely “pristine” and sparsely populated by slash-and-burn agriculturists, or instead a densely populated, domesticated landscape, heavily altered by extensive deforestation and anthropogenic burning. The discovery of hundreds of large geometric earthworks beneath intact rainforest across southern Amazonia challenges its status as a pristine landscape, and has been assumed to indicate extensive pre-Columbian deforestation by large populations. We tested these assumptions using coupled local- and regional-scale paleoecological records to reconstruct land use on an earthwork site in northeast Bolivia within the context of regional, climate-driven biome changes. This approach revealed evidence for an alternative scenario of Amazonian land use, which did not necessitate labor-intensive rainforest clearance for earthwork construction. Instead, we show that the inhabitants exploited a naturally open savanna landscape that they maintained around their settlement despite the climatically driven rainforest expansion that began ∼2,000 y ago across the region. Earthwork construction and agriculture on terra firme landscapes currently occupied by the seasonal rainforests of southern Amazonia may therefore not have necessitated large-scale deforestation using stone tools. This finding implies far less labor—and potentially lower population density—than previously supposed. Our findings demonstrate that current debates over the magnitude and nature of pre-Columbian Amazonian land use, and its impact on global biogeochemical cycling, are potentially flawed because they do not consider this land use in the context of climate-driven forest–savanna biome shifts through the mid-to-late Holocene. PMID:25002502

  11. New species and geographical records of dactylogyrids (Monogenea) of catfish (Siluriformes) from the Peruvian Amazonia.

    PubMed

    Mendoza-Palmero, Carlos A; Scholz, Tomáš; Mendoza-Franco, Edgar F; Kuchta, Roman

    2012-06-01

    Three new species of gill monogeneans (Dactylogyridae: Ancyrocephalinae) are described from siluriform catfish from Iquitos, Peru: Demidospermus mortenthaleri n. sp. from Brachyplatystoma juruense (Boulenger), Demidospermus brevicirrus n. sp. from Pimelodus sp., and Aphanoblastella aurorae n. sp. from Goeldiella eques (Müller & Troschel). Demidospermus mortenthaleri is characterized by a male copulatory organ (MCO) with a small loop at its middle portion; 2 types of hooks, of which pairs 5 and 6 are longer than the remaining hooks; a proximal subunit round and highly depressed thumb; and a sclerotized vagina with a round pad at the vaginal aperture. Demidospermus brevicirrus is distinguished from other congeners by the presence of a short, straight, and robust MCO and boot-shaped accessory piece with a hooked projection directed posteriorly. Aphanoblastella aurorae is the only species of the genus that possesses an arrow-shaped sclerotized vagina and a medial process on the dorsal bar. Another 6 dactylogyrids described previously are recorded for the first time from the Peruvian Amazonia: Cosmetocleithrum bulbocirrus Kritsky, Thatcher and Boeger, 1986 ; Vancleaveus fungulus Kritsky, Thatcher and Boeger, 1986 ; V. janauacaensis Kritsky, Thatcher and Boeger, 1986 ; V. platyrhynchi Kritsky, Thatcher and Boeger, 1986 ; Unilatus unilatus Mizelle and Kritsky, 1967 ; and U. brittani Mizelle, Kritsky and Crane, 1968 . Based on observations of specimens collected in the Peruvian Amazonia, new morphological data for these species are provided. Comparison of new specimens of U. unilatus and U. brittani with those of Unilatus brevispinus Suriano, 1985 and Unilatus longispinus Suriano, 1985 , both originally described from Brazil, has shown that they are conspecific. Therefore, the latter species were synonymized with U. unilatus and U. brittani , respectively. In addition, 56 undescribed monogeneans found in catfish from the Peruvian Amazonia, some of them probably belonging

  12. N2O Emissions in Southeastern Amazonia: The Effect of Agricultural Intensification

    NASA Astrophysics Data System (ADS)

    O'Connell, C.; Brando, P. M.; Cerri, C. E.; Coe, M. T.; Davidson, E. A.; Galford, G. L.; Macedo, M.; Neill, C.; Venterea, R. T.

    2014-12-01

    The Amazon is not only an exceptionally biodiverse and carbon-rich tract of tropical forest, it is also a case study in land use change. Over the last 30 years, Amazonia has been home to extraordinary growth in agricultural production, in part from agricultural expansion, but also due to more intense management on Amazonia's existing croplands. We use a year-long campaign and approximately 500 field chamber measurements to estimate how cropland intensification in Mato Grosso, Brazil affects the emission of nitrous oxide (N2O) and soil N dynamics. In this system, soybean cropland intensification occurs when double cropping is introduced, in which maize is planted directly after soybean harvest and fertilized twice with inorganic N. We find that dry season N2O emissions in single-cropped (soybean only) fields, double-cropped (soybean/maize) fields and reference tropical forest are uniformly near zero, or ~0-0.5 ngN/cm^2/hr. Surprisingly, wet season emissions rates remain low as well, between 1-4 ngN/cm^2/hr, for both cropland types and reference forest. By contrast, isolated post-fertilization spikes in N2O emissions are large, with a maximum increase of ~800% and a mean increase of ~400%, though these flux increases resolve rapidly and rates return to their low baseline within days. Finally, we explore the role that soil moisture, soil N availability, and soil C availability play in regulating N2O fluxes in reference forest, soybean fields and intensified soybean-maize fields. Open questions surround how the Amazon's land resources can be leveraged to increase agricultural production at the least harm to the environment. Here, we quantify the consequences of land use change on N2O, a powerful greenhouse gas, in a critical ecosystem undergoing novel agricultural intensification. These results may inform both greenhouse gas accounting and our understanding of the effects of Amazonia's changing agricultural landscape on the nitrogen cycle.

  13. Pre-Columbian agricultural landscapes, ecosystem engineers, and self-organized patchiness in Amazonia

    PubMed Central

    McKey, Doyle; Rostain, Stéphen; Iriarte, José; Glaser, Bruno; Birk, Jago Jonathan; Holst, Irene; Renard, Delphine

    2010-01-01

    The scale and nature of pre-Columbian human impacts in Amazonia are currently hotly debated. Whereas pre-Columbian people dramatically changed the distribution and abundance of species and habitats in some parts of Amazonia, their impact in other parts is less clear. Pioneer research asked whether their effects reached even further, changing how ecosystems function, but few in-depth studies have examined mechanisms underpinning the resilience of these modifications. Combining archeology, archeobotany, paleoecology, soil science, ecology, and aerial imagery, we show that pre-Columbian farmers of the Guianas coast constructed large raised-field complexes, growing on them crops including maize, manioc, and squash. Farmers created physical and biogeochemical heterogeneity in flat, marshy environments by constructing raised fields. When these fields were later abandoned, the mosaic of well-drained islands in the flooded matrix set in motion self-organizing processes driven by ecosystem engineers (ants, termites, earthworms, and woody plants) that occur preferentially on abandoned raised fields. Today, feedbacks generated by these ecosystem engineers maintain the human-initiated concentration of resources in these structures. Engineer organisms transport materials to abandoned raised fields and modify the structure and composition of their soils, reducing erodibility. The profound alteration of ecosystem functioning in these landscapes coconstructed by humans and nature has important implications for understanding Amazonian history and biodiversity. Furthermore, these landscapes show how sustainability of food-production systems can be enhanced by engineering into them fallows that maintain ecosystem services and biodiversity. Like anthropogenic dark earths in forested Amazonia, these self-organizing ecosystems illustrate the ecological complexity of the legacy of pre-Columbian land use. PMID:20385814

  14. Environmental impact of geometric earthwork construction in pre-Columbian Amazonia.

    PubMed

    Carson, John Francis; Whitney, Bronwen S; Mayle, Francis E; Iriarte, José; Prümers, Heiko; Soto, J Daniel; Watling, Jennifer

    2014-07-22

    There is considerable controversy over whether pre-Columbian (pre-A.D. 1492) Amazonia was largely "pristine" and sparsely populated by slash-and-burn agriculturists, or instead a densely populated, domesticated landscape, heavily altered by extensive deforestation and anthropogenic burning. The discovery of hundreds of large geometric earthworks beneath intact rainforest across southern Amazonia challenges its status as a pristine landscape, and has been assumed to indicate extensive pre-Columbian deforestation by large populations. We tested these assumptions using coupled local- and regional-scale paleoecological records to reconstruct land use on an earthwork site in northeast Bolivia within the context of regional, climate-driven biome changes. This approach revealed evidence for an alternative scenario of Amazonian land use, which did not necessitate labor-intensive rainforest clearance for earthwork construction. Instead, we show that the inhabitants exploited a naturally open savanna landscape that they maintained around their settlement despite the climatically driven rainforest expansion that began ∼2,000 y ago across the region. Earthwork construction and agriculture on terra firme landscapes currently occupied by the seasonal rainforests of southern Amazonia may therefore not have necessitated large-scale deforestation using stone tools. This finding implies far less labor--and potentially lower population density--than previously supposed. Our findings demonstrate that current debates over the magnitude and nature of pre-Columbian Amazonian land use, and its impact on global biogeochemical cycling, are potentially flawed because they do not consider this land use in the context of climate-driven forest-savanna biome shifts through the mid-to-late Holocene.

  15. New species of Lachesilla Westwood in the pedicularia group (Psocodea: 'Psocoptera': Lachesillidae) from the Colombian Amazonia.

    PubMed

    Manchola, Oscar Fernando Saenz; Aldrete, Alfonso Neri García; Obando, Ranulfo González

    2015-02-05

    Two species of Lachesilla, in the pedicularia species group, from the Colombian Amazonia, are here described and illustrated. Also, a record of L. asymmetriproctus García Aldrete, for the Colombian Department of Putumayo is provided. An identification key to Lachesilla species in the pedicularia group with a single male clunial apophysis is presented, together with a diagnosis of this assemblage of species. A table is included indicating the distribution of Lachesilla species with one and two male clunial apophyses. The species treated in this paper constitute the first lachesillids known from the Department of Putumayo, Colombia. 

  16. Isolation of yellow fever virus from nulliparous Haemagogus (Haemagogus) janthinomys in eastern Amazonia.

    PubMed

    Mondet, B; Vasconcelos, P F C; Travassos da Rosa, A P A; Travassos da Rosa, E S; Rodrigues, S G; Travassos Rosa, J F S; Bicout, D J

    2002-01-01

    In 1998, an epizootic of yellow fever (YF) killed many howler monkeys (Alouatta spp.) in eastern Amazonia near the city of Altamira. An infection level with YF virus of approximately 3.6% was determined from analysis of 456 females of Haemagogus janthinomys Dyar, the main enzootic YF vector in South America. One month later, a second study of 164 females captured in the same place led to infection levels of 0.8% for parous and 2.9% for nulliparous females. These results lead to the conclusion that vertical transmission, one of the key elements in the epidemiology of YF, occurs in South America as it does in Africa.

  17. Reduced deep soil water uptake through forest conversion to pasture in Amazonia

    SciTech Connect

    Jipp, P.H.; Nepstad, D.C. Woods Hole Research Center, MA )

    1993-06-01

    Forests of eastern Amazonia are being replaced by pastures and secondary forests. We measured soil water storage and flux in adjacent forest and pasture ecosystems using Time Domain Reflectometry sensors installed in the walls of deep (9-m) shafts. The forest withdrew 597+/-25 mm of soil water stored below 1 m depth during the 1991 dry season (Jun-Dec), 1.7 times more than the pasture. Uptake from the bottom of the forest soil profile continued even after rainfall resumed in early 1992. The hydrologic impacts of tropical deforestation may be most severe for evergreen forests with deep rooting zones in areas of seasonal drought.

  18. The Flux of Carbon from Selective Logging, Fire, and Regrowth in Amazonia

    NASA Technical Reports Server (NTRS)

    Houghton, R. A.

    2004-01-01

    The major goal of this work was to develop a spatial, process-based model (CARLUC) that would calculate sources and sinks of carbon from changes in land use, including logging and fire. The work also included Landsat data, together with fieldwork, to investigate fire and logging in three different forest types within Brazilian Amazonia. Results from these three activities (modeling, fieldwork, and remote sensing) are described, individually, below. The work and some of the personnel overlapped with research carried out by Dr. Daniel Nepstad's LBA team, and thus some of the findings are also reported in his summaries.

  19. Vegetation and climate changes in western Amazonia during a previous Interglacial- Glacial transition

    NASA Astrophysics Data System (ADS)

    Cardenas, M. L.; Gosling, W. D.; Sherlock, S. C.; Poole, I.; Pennington, R. T.

    2009-12-01

    Amazonia is one of the most biodiverse areas of the world and its vegetation plays a crucial role in controlling the global climate through the regulation of the levels of atmospheric CO2. However, Amazonian ecosystems and their role in the climate system are threatened by ongoing the human impact (already estimated loss of 60% of the species in western Amazonia) and predicted climate change (+1.1-6.4oC by 2100). Unfortunately, there is absence of data relating to the ecological baseline function and response to global climate change of western Amazonian ecosystems in the absence of humans. To help anticipate the impact of future climate change predictions an improved understanding of the natural responses of tropical vegetation to known past climate change is required. Here we present the first study that shows the response of pristine tropical ecosystems in western Amazonia biodiversity hotspot to a major global climate change event (a Quaternary Interglacial-Glacial transition). Pleistocene lake/swamp sediments preserved at the Erazo study site (Lat. 00o 33’S, Long. 077o 52’W, 1927m alt.) today within tropical cloud forest vegetation provide a unique opportunity to examine the impact of past climate shifts. The sediment are >40,000 years old (radiocarbon infinite) and younger than 1 million years (presence of Alder biomarker) and consist of organic layers interbedded with volcanic ash (tephra). This study presents data from multiple proxies (fossil pollen, wood macrofossils and charcoal) to establish a comprehensive picture of regional and local vegetation change prior to human arrival. Our data show a change of vegetation from palm-dominated forest indicative of warm and wet conditions similar to the present at the base of this record, to a forest dominated by Podocarpus sp. suggesting cold and wet conditions at the top of the record. The transition between these two vegetation communities appears to be progressive with small sharp changes along the

  20. Occurrence of filamentous fungi in Simulium goeldii Cerqueira & Nunes de Mello (diptera: simuliidae) larvae in central Amazonia, Brazil

    PubMed Central

    Fonseca, Quézia Ribeiro; de Moura Sarquis, Maria Inez; Hamada, Neusa; Alencar, Yamile Benaion

    2008-01-01

    The family Simuliidae is the host of simbiontes fungi that inhabit the digestive tracts of arthropods. This paper reports the presence of fungi in Simulium goeldii Cerqueira & Nunes de Mello larvae in Amazonia. We observed that the larvae are a good component of aquatic systems to isolate filamentous fungi. PMID:24031217

  1. Early and middle holocene hunter-gatherer occupations in western Amazonia: the hidden shell middens.

    PubMed

    Lombardo, Umberto; Szabo, Katherine; Capriles, José M; May, Jan-Hendrik; Amelung, Wulf; Hutterer, Rainer; Lehndorff, Eva; Plotzki, Anna; Veit, Heinz

    2013-01-01

    We report on previously unknown early archaeological sites in the Bolivian lowlands, demonstrating for the first time early and middle Holocene human presence in western Amazonia. Multidisciplinary research in forest islands situated in seasonally-inundated savannahs has revealed stratified shell middens produced by human foragers as early as 10,000 years ago, making them the oldest archaeological sites in the region. The absence of stone resources and partial burial by recent alluvial sediments has meant that these kinds of deposits have, until now, remained unidentified. We conducted core sampling, archaeological excavations and an interdisciplinary study of the stratigraphy and recovered materials from three shell midden mounds. Based on multiple lines of evidence, including radiocarbon dating, sedimentary proxies (elements, steroids and black carbon), micromorphology and faunal analysis, we demonstrate the anthropogenic origin and antiquity of these sites. In a tropical and geomorphologically active landscape often considered challenging both for early human occupation and for the preservation of hunter-gatherer sites, the newly discovered shell middens provide evidence for early to middle Holocene occupation and illustrate the potential for identifying and interpreting early open-air archaeological sites in western Amazonia. The existence of early hunter-gatherer sites in the Bolivian lowlands sheds new light on the region's past and offers a new context within which the late Holocene "Earthmovers" of the Llanos de Moxos could have emerged.

  2. Meso-scale drivers of forest structure and function in northwestern Amazonia

    NASA Astrophysics Data System (ADS)

    Higgins, M.; Asner, G. P.; Anderson, C.; Martin, R.; Knapp, D. E.; Perez, E.; Elespuru, N.; Alonso, A.

    2013-12-01

    Continent-scale studies of Amazonia have found patterns in forest structure and function corresponding to broad-scale patterns in soil properties. Little information exists at finer scales, however, about how patterns in forest structure, biomass, and canopy chemistry are distributed across Amazonian landscapes, and the underlying drivers of these patterns. Here we used airborne LiDAR and imaging spectroscopy to measure variations in forest structure, biomass, and canopy reflectance for more than 600 km2 of forest in northwestern Amazonia. We combined these data with information on plant species composition and soil properties for 78 sites distributed evenly between two underlying geological formations. We found that soil properties and plant species composition individually explained 70-80% of the variation in biomass in these forests. We further found that these variations in soils and species composition corresponded to profound changes in forest vertical structure. We last found that soil variables and plant species composition explained more than 90% of the variation in canopy chemistry as measured by imaging spectroscopy, resulting in distinct patterns in canopy reflectance. We conclude that soil properties and plant species composition are the dominant drivers of structural and functional patterns in northwestern Amazonian forests over scales of 10s to 100s of kilometers, and that these patterns correspond to underlying geological formations. At broader scales, we anticipate that soil properties and underlying geology provide a scaffold for forest structure and function upon which variations due to climate or distance are superimposed.

  3. Coupling Between the Climate Variables of Amazonia and its Surrounding Oceans During Drought Periods.

    NASA Astrophysics Data System (ADS)

    Ramos, Antônio M. de T.; Macau, Elbert E. N.

    2016-04-01

    Teleconnection patterns between different climate systems have been seen as a feature of the internal dynamics of atmosphere and ocean. However several questions about this non-linear dynamics remain open, especially the interplay of the warming of Oceans and the anomaly precipitation in the Amazon region. For this reason, we investigate how the coupling between the ocean's temperature and the precipitation in Amazon evolve in time. In particular, how does this coupling behave during an anomalous drought period in Amazonia. Here a data-driven approach is applied to detect the coupling time scale between the precipitation in the North/South Amazonia and its surrounding oceans. The framework comprises statistical and information theory approaches that can reveal directional links between the different regional domains. The method is applied on a daily resolution data sets, the variables are average over regional domains well studied in the literature. Finally, the outcomes are systematically analysed seeking patterns that may reveal the underlying dynamics between these climate systems. Also, the study sheds light into the elementary form of the climate network between these systems.

  4. Pre-Columbian Floristic Legacies in Modern Homegardens of Central Amazonia

    PubMed Central

    Lins, Juliana; Lima, Helena P.; Baccaro, Fabricio B.; Kinupp, Valdely F.; Shepard, Glenn H.; Clement, Charles R.

    2015-01-01

    Historical ecologists have demonstrated legacy effects in apparently wild landscapes in Europe, North America, Mesoamerica, Amazonia, Africa and Oceania. People live and farm in archaeological sites today in many parts of the world, but nobody has looked for the legacies of past human occupations in the most dynamic areas in these sites: homegardens. Here we show that the useful flora of modern homegardens is partially a legacy of pre-Columbian occupations in Central Amazonia: the more complex the archaeological context, the more variable the floristic composition of useful native plants in homegardens cultivated there today. Species diversity was 10% higher in homegardens situated in multi-occupational archaeological contexts compared with homegardens situated in single-occupational ones. Species heterogeneity (β-diversity) among archaeological contexts was similar for the whole set of species, but markedly different when only native Amazonian species were included, suggesting the influence of pre-conquest indigenous occupations on current homegarden species composition. Our findings show that the legacy of pre-Columbian occupations is visible in the most dynamic of all agroecosystems, adding another dimension to the human footprint in the Amazonian landscape. PMID:26030879

  5. Brazil's Samuel Dam: lessons for hydroelectric development policy and the environment in Amazonia.

    PubMed

    Fearnside, Philip M

    2005-01-01

    Brazil's Samuel Dam, which formed a 540-km2 reservoir in the state of Rondônia in 1988, provides lessons for development decisions throughout Amazonia and in other tropical areas. The decision to build the dam was heavily influenced by its role in the political strategies of key decision makers. Samuel illustrates both impacts and benefits of electricity supply and the dilemmas facing decision makers regarding the various options for planned electricity generation. Environmental costs included flooding forest and stimulating illegal logging activity throughout western Amazonia because of an exception opened for Samuel in Brazil's prohibition of export of raw logs. Samuel emitted substantially more greenhouse gases than would have been emitted by generating the same amount of electricity from oil. Contamination of fish in the reservoir resulted from methylation of mercury present in the soil. Social costs of the dam included resettlement of 238 families of farmers; impacts on indigenous people were indirect. Mitigating measures included faunal rescue and creation of a forest reserve. The lessons of Samuel include the need to consider a full range of alternatives prior to making decisions in practice and the importance of adhering to the logical sequence of decision making, where information is gathered and compared prior to the decision. It also shows the need to maintain flexibility when the costs and benefits of different alternatives change significantly over the course of the project's planning and execution, as occurred at Samuel.

  6. Use of MODIS Sensor Images Combined with Reanalysis Products to Retrieve Net Radiation in Amazonia

    PubMed Central

    de Oliveira, Gabriel; Brunsell, Nathaniel A.; Moraes, Elisabete C.; Bertani, Gabriel; dos Santos, Thiago V.; Shimabukuro, Yosio E.; Aragão, Luiz E. O. C.

    2016-01-01

    In the Amazon region, the estimation of radiation fluxes through remote sensing techniques is hindered by the lack of ground measurements required as input in the models, as well as the difficulty to obtain cloud-free images. Here, we assess an approach to estimate net radiation (Rn) and its components under all-sky conditions for the Amazon region through the Surface Energy Balance Algorithm for Land (SEBAL) model utilizing only remote sensing and reanalysis data. The study period comprised six years, between January 2001–December 2006, and images from MODIS sensor aboard the Terra satellite and GLDAS reanalysis products were utilized. The estimates were evaluated with flux tower measurements within the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) project. Comparison between estimates obtained by the proposed method and observations from LBA towers showed errors between 12.5% and 16.4% and 11.3% and 15.9% for instantaneous and daily Rn, respectively. Our approach was adequate to minimize the problem related to strong cloudiness over the region and allowed to map consistently the spatial distribution of net radiation components in Amazonia. We conclude that the integration of reanalysis products and satellite data, eliminating the need for surface measurements as input model, was a useful proposition for the spatialization of the radiation fluxes in the Amazon region, which may serve as input information needed by algorithms that aim to determine evapotranspiration, the most important component of the Amazon hydrological balance. PMID:27347957

  7. Aerosol chemistry during the wet season in central Amazonia - The influence of long-range transport

    NASA Technical Reports Server (NTRS)

    Talbot, R. W.; Andreae, M. O.; Berresheim, H.; Artaxo, P.; Garstang, M.

    1990-01-01

    The temporal variation in the concentration and chemistry of the atmospheric aerosol over central Amazonia, Brazil, during the 1987 wet season is discussed based on ground and aircraft collected data obtained during the NASA GTE ABLE 2B expedition conducted in April/May 1987. It is found that wet-season aerosol concentrations and composition are variable in contrast to the more uniform biogenic aerosol observed during the 1985 dry season; four distinct intervals of enhanced aerosol concentration coincided with short periods (3 to 5 d) of extensive rainfall. It is hypothesized that aerosol chemistry in Amazonia during the wet season is strongly influenced by long-range transport of soil dust, marine aerosol, and possibly biomass combustion products advected into the central Basin by large-scale tropospheric circulation, producing periodic pulses of material input to local boundary layer air. The resultant wet-season aerosol regime is dynamic, in contrast to the uniformity of natural biogenic aerosols during the dry season.

  8. Use of MODIS Sensor Images Combined with Reanalysis Products to Retrieve Net Radiation in Amazonia.

    PubMed

    de Oliveira, Gabriel; Brunsell, Nathaniel A; Moraes, Elisabete C; Bertani, Gabriel; Dos Santos, Thiago V; Shimabukuro, Yosio E; Aragão, Luiz E O C

    2016-06-24

    In the Amazon region, the estimation of radiation fluxes through remote sensing techniques is hindered by the lack of ground measurements required as input in the models, as well as the difficulty to obtain cloud-free images. Here, we assess an approach to estimate net radiation (Rn) and its components under all-sky conditions for the Amazon region through the Surface Energy Balance Algorithm for Land (SEBAL) model utilizing only remote sensing and reanalysis data. The study period comprised six years, between January 2001-December 2006, and images from MODIS sensor aboard the Terra satellite and GLDAS reanalysis products were utilized. The estimates were evaluated with flux tower measurements within the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) project. Comparison between estimates obtained by the proposed method and observations from LBA towers showed errors between 12.5% and 16.4% and 11.3% and 15.9% for instantaneous and daily Rn, respectively. Our approach was adequate to minimize the problem related to strong cloudiness over the region and allowed to map consistently the spatial distribution of net radiation components in Amazonia. We conclude that the integration of reanalysis products and satellite data, eliminating the need for surface measurements as input model, was a useful proposition for the spatialization of the radiation fluxes in the Amazon region, which may serve as input information needed by algorithms that aim to determine evapotranspiration, the most important component of the Amazon hydrological balance.

  9. A palaeobiogeographic model for biotic diversification within Amazonia over the past three million years.

    PubMed

    Ribas, Camila C; Aleixo, Alexandre; Nogueira, Afonso C R; Miyaki, Cristina Y; Cracraft, Joel

    2012-02-22

    Many hypotheses have been proposed to explain high species diversity in Amazonia, but few generalizations have emerged. In part, this has arisen from the scarcity of rigorous tests for mechanisms promoting speciation, and from major uncertainties about palaeogeographic events and their spatial and temporal associations with diversification. Here, we investigate the environmental history of Amazonia using a phylogenetic and biogeographic analysis of trumpeters (Aves: Psophia), which are represented by species in each of the vertebrate areas of endemism. Their relationships reveal an unforeseen 'complete' time-slice of Amazonian diversification over the past 3.0 Myr. We employ this temporally calibrated phylogeny to test competing palaeogeographic hypotheses. Our results are consistent with the establishment of the current Amazonian drainage system at approximately 3.0-2.0 Ma and predict the temporal pattern of major river formation over Plio-Pleistocene times. We propose a palaeobiogeographic model for the last 3.0 Myr of Amazonian history that has implications for understanding patterns of endemism, the temporal history of Amazonian diversification and mechanisms promoting speciation. The history of Psophia, in combination with new geological evidence, provides the strongest direct evidence supporting a role for river dynamics in Amazonian diversification, and the absence of such a role for glacial climate cycles and refugia.

  10. Avian malaria, ecological host traits and mosquito abundance in southeastern Amazonia.

    PubMed

    Fecchio, Alan; Ellis, Vincenzo A; Bell, Jeffrey A; Andretti, Christian B; D'Horta, Fernando M; Silva, Allan M; Tkach, Vasyl V; Weckstein, Jason D

    2017-03-27

    Avian malaria is a vector transmitted disease caused by Plasmodium and recent studies suggest that variation in its prevalence across avian hosts is correlated with a variety of ecological traits. Here we examine the relationship between prevalence and diversity of Plasmodium lineages in southeastern Amazonia and: (1) host ecological traits (nest location, nest type, flocking behaviour and diet); (2) density and diversity of avian hosts; (3) abundance and diversity of mosquitoes; and (4) season. We used molecular methods to detect Plasmodium in blood samples from 675 individual birds of 120 species. Based on cytochrome b sequences, we recovered 89 lineages of Plasmodium from 136 infected individuals sampled across seven localities. Plasmodium prevalence was homogeneous over time (dry season and flooding season) and space, but heterogeneous among 51 avian host species. Variation in prevalence among bird species was not explained by avian ecological traits, density of avian hosts, or mosquito abundance. However, Plasmodium lineage diversity was positively correlated with mosquito abundance. Interestingly, our results suggest that avian host traits are less important determinants of Plasmodium prevalence and diversity in southeastern Amazonia than in other regions in which they have been investigated.

  11. Pre-Columbian floristic legacies in modern homegardens of Central Amazonia.

    PubMed

    Lins, Juliana; Lima, Helena P; Baccaro, Fabricio B; Kinupp, Valdely F; Shepard, Glenn H; Clement, Charles R

    2015-01-01

    Historical ecologists have demonstrated legacy effects in apparently wild landscapes in Europe, North America, Mesoamerica, Amazonia, Africa and Oceania. People live and farm in archaeological sites today in many parts of the world, but nobody has looked for the legacies of past human occupations in the most dynamic areas in these sites: homegardens. Here we show that the useful flora of modern homegardens is partially a legacy of pre-Columbian occupations in Central Amazonia: the more complex the archaeological context, the more variable the floristic composition of useful native plants in homegardens cultivated there today. Species diversity was 10% higher in homegardens situated in multi-occupational archaeological contexts compared with homegardens situated in single-occupational ones. Species heterogeneity (β-diversity) among archaeological contexts was similar for the whole set of species, but markedly different when only native Amazonian species were included, suggesting the influence of pre-conquest indigenous occupations on current homegarden species composition. Our findings show that the legacy of pre-Columbian occupations is visible in the most dynamic of all agroecosystems, adding another dimension to the human footprint in the Amazonian landscape.

  12. The Cotingo Dam as a Test of Brazil's System for Evaluating Proposed Developments in Amazonia

    PubMed

    Fearnside; Barbosa

    1996-09-01

    The proposed Cotingo Dam in Brazil's far northern state of Roraima is examined with the objective of drawing lessons for Brazil's system of evaluating environmental, social, and financial consequences of development decisions. The Cotingo Dam illustrates the difficulty of translating into practice the principles of economic and environmental assessment. Examination of the financial arguments for the Cotingo Dam indicates that justifications in this sphere are insufficient to explain why the project is favored over other alternatives and points to political factors as the best explanation of the project's high priority. Strong pressure from political and entrepreneurial interest groups almost invariably dominates decision making in Amazonia. The analysis indicates the inherent tendency of the present system to produce decisions in favor of large construction projects at the expense of the environment and local peoples. The requirements intended to assure proper weight for these concerns, such as the report on environmental impacts (RIMA) and the public hearing, fail to serve this role. Cotingo also provides a test case for constitutional protections restricting construction of dams in indigenous lands.KEY WORDS: Hydroelectric dams; Amazonia; Indigenous peoples; Brazil; Roraima

  13. Early and Middle Holocene Hunter-Gatherer Occupations in Western Amazonia: The Hidden Shell Middens

    PubMed Central

    Lombardo, Umberto; Szabo, Katherine; Capriles, José M.; May, Jan-Hendrik; Amelung, Wulf; Hutterer, Rainer; Lehndorff, Eva; Plotzki, Anna; Veit, Heinz

    2013-01-01

    We report on previously unknown early archaeological sites in the Bolivian lowlands, demonstrating for the first time early and middle Holocene human presence in western Amazonia. Multidisciplinary research in forest islands situated in seasonally-inundated savannahs has revealed stratified shell middens produced by human foragers as early as 10,000 years ago, making them the oldest archaeological sites in the region. The absence of stone resources and partial burial by recent alluvial sediments has meant that these kinds of deposits have, until now, remained unidentified. We conducted core sampling, archaeological excavations and an interdisciplinary study of the stratigraphy and recovered materials from three shell midden mounds. Based on multiple lines of evidence, including radiocarbon dating, sedimentary proxies (elements, steroids and black carbon), micromorphology and faunal analysis, we demonstrate the anthropogenic origin and antiquity of these sites. In a tropical and geomorphologically active landscape often considered challenging both for early human occupation and for the preservation of hunter-gatherer sites, the newly discovered shell middens provide evidence for early to middle Holocene occupation and illustrate the potential for identifying and interpreting early open-air archaeological sites in western Amazonia. The existence of early hunter-gatherer sites in the Bolivian lowlands sheds new light on the region’s past and offers a new context within which the late Holocene “Earthmovers” of the Llanos de Moxos could have emerged. PMID:24013964

  14. Outstanding insecurities concerning the use of an Ov16-based ELISA in the Amazonia onchocerciasis focus.

    PubMed

    Luz, Sérgio Luiz Bessa; Crainey, James Lee; Shelley, Anthony John; Rubio, Miguel

    2014-07-01

    In a recent issue of Memórias do Instituto Oswaldo Cruz, published in Rio de Janeiro in February 2014 (109: 87-92), Adami et al. have published a survey reporting Mansonella parasite prevalence in the Amazon Region. This report makes a useful contribution to the existing knowledge of filarial parasite distribution within the Amazon area, parasite prevalence rates in relation to age and occupation and provides observations on the possible clinical impact of Mansonella ozzardi. Their publication also provides an account of what appears to be a novel ELISA that has recently been used in the Simuliidae and Onchocerciasis Laboratory of the Oswaldo Cruz Institute, Rio de Janeiro, Brazil. We are concerned that the publication of this ELISA may have created an excessively positive impression of the effectiveness of the onchocerciasis recrudescence serological surveillance tools that are presently available for use in the Amazonia onchocerciasis focus. In this letter we have, thus, sought to highlight some of the limitations of this ELISA and suggest how continuing insecurities concerning the detection of antibodies to Onchocerca volvulus within the Amazonia onchocerciasis focus might be minimised.

  15. A palaeobiogeographic model for biotic diversification within Amazonia over the past three million years

    PubMed Central

    Ribas, Camila C.; Aleixo, Alexandre; Nogueira, Afonso C. R.; Miyaki, Cristina Y.; Cracraft, Joel

    2012-01-01

    Many hypotheses have been proposed to explain high species diversity in Amazonia, but few generalizations have emerged. In part, this has arisen from the scarcity of rigorous tests for mechanisms promoting speciation, and from major uncertainties about palaeogeographic events and their spatial and temporal associations with diversification. Here, we investigate the environmental history of Amazonia using a phylogenetic and biogeographic analysis of trumpeters (Aves: Psophia), which are represented by species in each of the vertebrate areas of endemism. Their relationships reveal an unforeseen ‘complete’ time-slice of Amazonian diversification over the past 3.0 Myr. We employ this temporally calibrated phylogeny to test competing palaeogeographic hypotheses. Our results are consistent with the establishment of the current Amazonian drainage system at approximately 3.0–2.0 Ma and predict the temporal pattern of major river formation over Plio-Pleistocene times. We propose a palaeobiogeographic model for the last 3.0 Myr of Amazonian history that has implications for understanding patterns of endemism, the temporal history of Amazonian diversification and mechanisms promoting speciation. The history of Psophia, in combination with new geological evidence, provides the strongest direct evidence supporting a role for river dynamics in Amazonian diversification, and the absence of such a role for glacial climate cycles and refugia. PMID:21795268

  16. Land-use in Amazonia and the Cerrado of Brazil: State of Knowledge and GIS Database

    NASA Technical Reports Server (NTRS)

    Nepstad, Daniel C.

    1997-01-01

    We have assembled datasets to strengthen the LargeScale Biosphere Atmosphere Experiment in Amazonia (LBA). These datasets can now be accessed through the Woods Hole Research Center homepage (www.whrc.org), and will soon be linked to the Pre-LBA homepages of the Brazilian Space Research Institute's Center for Weather and Climate Prediction (Instituto de Pesquisas Espaciais, Centro de Previsao de Tempo e Estudos Climaticos, INPE/CPTEC) and through the Oak Ridge National Laboratory, Distributed Active Archive Center (ORNL/DMC). Some of the datasets that we are making available involved new field research and/or the digitization of data available in Brazilian government agencies. For example, during the grant period we conducted interviews at 1,100 sawmills across Amazonia to determine their production of sawn timber, and their harvest intensities. These data provide the basis for the first quantitative assessment of the area of forest affected each year by selective logging (Nepstad et al, submitted to Nature). We digitized the locations of all of the rural households in the State of Para that have been mapped by the Brazilian malaria combat agency (SUCAM). We also mapped and digitized areas of deforestation in the state of Tocantins, which is comprised largely of savanna (cerrado), an ecosystem that has been routinely excluded from deforestation mapping exercises.

  17. Aerosol transport along the Andes from Amazonia to the remote Pacific Ocean: A multiyear CALIOP assessment

    NASA Astrophysics Data System (ADS)

    Bourgeois, Quentin; Ekman, Annica; Krejci, Radovan

    2015-04-01

    The free troposphere over South America and the Pacific Ocean is a particularly interesting region to study due to the prevailing easterly wind direction, forcing air over Amazonia towards the Pacific Ocean but encountering a natural barrier - the Andes - in between which might play a significant role. In addition, the strong contrast between the wet, relatively clean season and the dry, relatively polluted season as well as the difference between day and night meteorological conditions may influence the vertical distribution of aerosols in the free troposphere. Six years (2007-2012) of CALIOP observations at both day and night were used to investigate the vertical distribution, transport and removal processes of aerosols over South America and the Pacific Ocean. The multiyear assessment shows that aerosols, mainly biomass burning particles emitted during the dry season in Amazonia, may be lifted along the Andes. During their lifting, aerosols remain in the boundary layer which makes them subject to scavenging and deposition processes. The removal aerosol extinction rate was quantified. After reaching the top of the Andes, free tropospheric aerosols are likely pushed by the large-scale subsidence towards the marine boundary layer (MBL) during their transport over the Pacific Ocean. CALIOP observations may indicate that aerosols are transported over thousands of kilometers in the free troposphere over the Pacific Ocean. During their long range transport, aerosols could be entrained into the MBL and may further act as cloud condensation nuclei, and influence climate and the radiative budget of the Earth.

  18. Understorey fire frequency and the fate of burned forests in southern Amazonia.

    PubMed

    Morton, D C; Le Page, Y; DeFries, R; Collatz, G J; Hurtt, G C

    2013-06-05

    Recent drought events underscore the vulnerability of Amazon forests to understorey fires. The long-term impact of fires on biodiversity and forest carbon stocks depends on the frequency of fire damages and deforestation rates of burned forests. Here, we characterized the spatial and temporal dynamics of understorey fires (1999-2010) and deforestation (2001-2010) in southern Amazonia using new satellite-based estimates of annual fire activity (greater than 50 ha) and deforestation (greater than 10 ha). Understorey forest fires burned more than 85 500 km(2) between 1999 and 2010 (2.8% of all forests). Forests that burned more than once accounted for 16 per cent of all understorey fires. Repeated fire activity was concentrated in Mato Grosso and eastern Pará, whereas single fires were widespread across the arc of deforestation. Routine fire activity in Mato Grosso coincided with annual periods of low night-time relative humidity, suggesting a strong climate control on both single and repeated fires. Understorey fires occurred in regions with active deforestation, yet the interannual variability of fire and deforestation were uncorrelated, and only 2.6 per cent of forests that burned between 1999 and 2008 were deforested for agricultural use by 2010. Evidence from the past decade suggests that future projections of frontier landscapes in Amazonia should separately consider economic drivers to project future deforestation and climate to project fire risk.

  19. The Greatest Legacy of the Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA): A Bibliometric Assessment

    NASA Astrophysics Data System (ADS)

    Keller, M. M.

    2015-12-01

    The Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA) is an international continental scale effort led by Brazil to understand how land use change and climate change affects the role of Amazonia in the Earth system. During the first decade of studies (1998-2007), LBA researchers generated new understanding of Amazonia and published over 1000 papers. However, most LBA participants agree that training and education of a large cohort of scientists, especially students from Brazil, was the greatest contribution of LBA. I analyzed bibliographic data from the NASA supported component project known as LBA-ECO. This component covered a large cross-section of the LBA subject areas highlighting land use and land cover change, carbon cycling, nutrient cycling and other aspects of terrestrial and aquatic ecology. I reviewed the complete bibliography of peer-reviewed papers reported by LBA-ECO researchers (http://www.lbaeco.org/cgi-bin/web/investigations/lbaeco_refs.pl). The researchers reported 691 contributions from 1996 through 2013 of which 24 were theses that were removed them from further analysis. Of 667 papers and book chapters, I tallied the first authors separating categories for Brazilians, all students, and Brazilian students. Numerically, LBA-ECO production of papers peaked in 2004. Publication by Brazilians, students, and Brazilian students generally followed the same pattern as publication in general. However, student and Brazilian student contributions as first authors showed clearly increasing proportions of the papers from project initiation through peak publication. Brazilian student participation as first authors averaged more than 20% of all publications from 2003 to 2010 and more than half of all student publications had Brazilians as first authors. Foreign researchers, some initially reluctant to invest in Brazilian students, almost universally adapted the belief that the greatest legacy of LBA would be the contribution to building a cadre of

  20. A new species of Bachia Gray, 1845 (Squamata: Gymnophthalmidae) from the western Brazilian Amazonia.

    PubMed

    Teixeira, Mauro; Dal Vechio, Francisco; Nunes, Pedro M Sales; Mollo Neto, Antonio; Lobo, Luciana Moreira; Storti, Luis Fernando; Junqueira, Renato Augusto; Dias, Pedro Henrique Freire; Rodorigues, Miguel Trefaut

    2013-01-01

    A new species of Bachia of the B. dorbignyi group, Bachia scaea sp. nov., is described from the left bank of the upper Madeira River, at Rondônia state, at the western Brazilian Amazonia. The new species resembles morphologically B. dorbignyi and B. peruana, and seems to be related with the former species based on molecular data (16S and c-mos sequences). Nonetheless the presence of a first temporal separating parietal and supralabial scales and the absence of clawed fingers in the new species, can promptly distinguish it from their close relatives. This description ends with several-decades of stasis in the taxonomy of the Bachia dorbignyi group from Amazonian lowlands, and also presents new evidence that supports the Madeira River as a vicariant barrier.

  1. Deforestation and climate feedbacks threaten the ecological integrity of south-southeastern Amazonia.

    PubMed

    Coe, Michael T; Marthews, Toby R; Costa, Marcos Heil; Galbraith, David R; Greenglass, Nora L; Imbuzeiro, Hewlley M A; Levine, Naomi M; Malhi, Yadvinder; Moorcroft, Paul R; Muza, Michel Nobre; Powell, Thomas L; Saleska, Scott R; Solorzano, Luis A; Wang, Jingfeng

    2013-06-05

    A mosaic of protected areas, including indigenous lands, sustainable-use production forests and reserves and strictly protected forests is the cornerstone of conservation in the Amazon, with almost 50 per cent of the region now protected. However, recent research indicates that isolation from direct deforestation or degradation may not be sufficient to maintain the ecological integrity of Amazon forests over the next several decades. Large-scale changes in fire and drought regimes occurring as a result of deforestation and greenhouse gas increases may result in forest degradation, regardless of protected status. How severe or widespread these feedbacks will be is uncertain, but the arc of deforestation in south-southeastern Amazonia appears to be particularly vulnerable owing to high current deforestation rates and ecological sensitivity to climate change. Maintaining forest ecosystem integrity may require significant strengthening of forest conservation on private property, which can in part be accomplished by leveraging existing policy mechanisms.

  2. Rhodnius barretti, a new species of Triatominae (Hemiptera: Reduviidae) from western Amazonia

    PubMed Central

    Abad-Franch, Fernando; Pavan, Márcio G; Jaramillo-O, Nicolás; Palomeque, Francisco S; Dale, Carolina; Chaverra, Duverney; Monteiro, Fernando A

    2013-01-01

    Rhodnius barretti , a new triatomine species, is described based on adult specimens collected in rainforest environments within the Napo ecoregion of western Amazonia (Colombia and Ecuador). R. barretti resembles Rhodnius robustus s.l. , but mitochondrial cytochrome b gene sequences reveal that it is a strongly divergent member of the “robustus lineage”, i.e., basal to the clade encompassing Rhodnius nasutus , Rhodnius neglectus , Rhodnius prolixus and five members of the R. robustus species complex. Morphometric analyses also reveal consistent divergence from R. robustus s.l. , including head and, as previously shown, wing shape and the length ratios of some anatomical structures. R. barretti occurs, often at high densities, in Attalea butyracea and Oenocarpus bataua palms. It is strikingly aggressive and adults may invade houses flying from peridomestic palms. R. barretti must therefore be regarded as a potential Trypanosoma cruzi vector in the Napo ecoregion, where Chagas disease is endemic. PMID:24473808

  3. Genetic diversity of red-bellied Titis (Callicebus moloch) from Eastern Amazonia based on microsatellite markers.

    PubMed

    Menescal, Luciana Alcantarino; Gonçalves, Evonnildo Costa; Silva, Artur; Ferrari, Stephen Francis; Schneider, Maria Paula Cruz

    2009-04-01

    The titi monkeys (Callicebus spp.) are a large, diverse genus of platyrrhines, widely distributed in tropical South America. The genetic variability of these monkeys is still relatively poorly known, especially at the population level. In the present study, four heterologous microsatellite markers were used to investigate genetic diversity in 23 individuals from a wild population of red-bellied titis (Callicebus moloch) in eastern Amazonia. An unexpectedly low level of diversity was found. The average number of alleles was 8.75 (range: 5-15), and the average heterozygosity was 0.33 (range: 0.09-0.65). This preliminary information suggests a reduction of the potential for long-term survival of the population and indicates the putative necessity of implementation of a species conservation program.

  4. Better RED than dead: paying the people for environmental services in Amazonia.

    PubMed

    Hall, Anthony

    2008-05-27

    The introduction of payments for environmental services (PES) offers an opportunity for traditional and indigenous populations to be compensated for contributing to carbon sequestration in meeting the challenge of ameliorating global warming. As one mechanism among several for promoting biodiversity conservation and sustainable development, pro-poor PES initiatives could eventually be incorporated into an international post-Koyoto framework to encourage reduced emissions from deforestation. Brazil's Proambiente PES scheme for small farmers in Amazonia has enjoyed some limited success, but it has fallen short of expectations. Its performance has been undermined by the lack of a national legal framework, limited funding, reduced implementation capacity, poor cross-sector collaboration and incompatibility with existing regional development policies. These challenges are being addressed by the federal government in cooperation with civil society with a view to scaling up Proambiente into a national programme.

  5. Deforestation and climate feedbacks threaten the ecological integrity of south–southeastern Amazonia

    PubMed Central

    Coe, Michael T.; Marthews, Toby R.; Costa, Marcos Heil; Galbraith, David R.; Greenglass, Nora L.; Imbuzeiro, Hewlley M. A.; Levine, Naomi M.; Malhi, Yadvinder; Moorcroft, Paul R.; Muza, Michel Nobre; Powell, Thomas L.; Saleska, Scott R.; Solorzano, Luis A.; Wang, Jingfeng

    2013-01-01

    A mosaic of protected areas, including indigenous lands, sustainable-use production forests and reserves and strictly protected forests is the cornerstone of conservation in the Amazon, with almost 50 per cent of the region now protected. However, recent research indicates that isolation from direct deforestation or degradation may not be sufficient to maintain the ecological integrity of Amazon forests over the next several decades. Large-scale changes in fire and drought regimes occurring as a result of deforestation and greenhouse gas increases may result in forest degradation, regardless of protected status. How severe or widespread these feedbacks will be is uncertain, but the arc of deforestation in south–southeastern Amazonia appears to be particularly vulnerable owing to high current deforestation rates and ecological sensitivity to climate change. Maintaining forest ecosystem integrity may require significant strengthening of forest conservation on private property, which can in part be accomplished by leveraging existing policy mechanisms. PMID:23610166

  6. Rhodnius barretti, a new species of Triatominae (Hemiptera: Reduviidae) from western Amazonia.

    PubMed

    Abad-Franch, Fernando; Pavan, Márcio G; Jaramillo-O, Nicolás; Palomeque, Francisco S; Dale, Carolina; Chaverra, Duverney; Monteiro, Fernando A

    2013-01-01

    Rhodnius barretti, a new triatomine species, is described based on adult specimens collected in rainforest environments within the Napo ecoregion of western Amazonia (Colombia and Ecuador). R. barretti resembles Rhodnius robustus s.l., but mitochondrial cytochrome b gene sequences reveal that it is a strongly divergent member of the "robustus lineage", i.e., basal to the clade encompassing Rhodnius nasutus, Rhodnius neglectus, Rhodnius prolixus and five members of the R. robustus species complex. Morphometric analyses also reveal consistent divergence from R. robustus s.l., including head and, as previously shown, wing shape and the length ratios of some anatomical structures. R. barretti occurs, often at high densities, in Attalea butyracea and Oenocarpus bataua palms. It is strikingly aggressive and adults may invade houses flying from peridomestic palms. R. barretti must therefore be regarded as a potential Trypanosoma cruzi vector in the Napo ecoregion, where Chagas disease is endemic.

  7. [Occurrence of Cephalonomia stephanoderis Betrem (Hymenoptera: Bethylidae) in coffee plantations of the Brazilian Amazonia].

    PubMed

    de Souza, Moisés S; Teixeira, César A D; Azevedo, Celso O; Costa, Valmir A; Costa, José N M

    2006-01-01

    Adults of Cephalonomia stephanoderis Betrem were detected (in November 2003) during the sampling of Coffea canephora Pierre ex A. Froehner berries damaged by Hypothenemus hampei Ferrari (Coleoptera: Scolytidae) in Ouro Preto D'Oeste - Rondônia, Brazil (10 degrees 45'S and 62 degrees 15'W). From January to July 2004, the parasitoid was monthly sampled in 200 berries damaged by H. hampei. Probably, C. stephanoderis can already exert some parasitism pressure at the coffee berry borer population. The occurrence of this parasitoid in natural conditions points out to another alternative for the biological control of the H. hampei in Rondônia. This is the first record of C. stephanoderis in coffee plantations of the Brazilian Amazonia.

  8. Rainfall and surface kinematic conditions over central amazonia during ABLE 2B

    NASA Technical Reports Server (NTRS)

    Greco, Steven; Swap, Robert; Garstang, Michael; Ulanski, Stanley; Shipham, Mark

    1990-01-01

    Rainfall, rainfall systems, and surface kinematics of the central Amazon basin wet season are investigated using meteorological and chemical data collected during the wet season Amazon Boundary Layer Experiment (ABLE) near Manaus, Brazil. Through analysis of (GOES-West) imagery, it is determined that, based on location of the initial development, there are three main types of convective systems which influence a mesoscale network near Manaus, namely the Coastal Occurring Systems (COS), the Basin Occurring Systems (BOS), and the Locally Occurring Systems (LOS). Chemical analysis of rainwater delivered by these systems shows significant differences in concentrations of formate, acetate, pyruvate, sulfate, and hydrogen ion, and measurements of aerosol concentrations near Manaus show large influxes of aerosols into central Amazonia after passage of BOS and COS. Results of satellite based classification of the rain-producing systems are discussed.

  9. Geographic distribution and possible taxonomic distinction of Callicebus torquatus populations (Pitheciidae: Primates) in Peruvian Amazonia.

    PubMed

    Aquino, Rolando; Terrones, Wagner; Cornejo, Fanny; Heymann, Eckhard W

    2008-12-01

    Population densities of yellow-handed titi monkey (Callicebus torquatus) were estimated using transect census methods. Densities were 2.8 individuals/km(2 )in the upper Rio Itaya basin and 2.5 individuals/km(2) in the lower Rio Algodón basin. Group size varied from two to five individuals, with an average of 2.9 individuals per group at the Rio Itaya. Groups were generally composed of two adults, probably the reproductive pair, with progeny from one to three previous birth seasons. Although the Rio Itaya population is phenotypically identical to populations from the rivers Nanay and Tigre, it differs from population on the rivers Napo and Putumayo. This suggests the existence of two disjunct populations of C. torquatus in Peruvian Amazonia whose taxonomic status warrants further examination.

  10. The response of vegetation on the Andean flank in western Amazonia to Pleistocene climate change.

    PubMed

    Cárdenas, Macarena L; Gosling, William D; Sherlock, Sarah C; Poole, Imogen; Pennington, R Toby; Mothes, Patricia

    2011-02-25

    A reconstruction of past environmental change from Ecuador reveals the response of lower montane forest on the Andean flank in western Amazonia to glacial-interglacial global climate change. Radiometric dating of volcanic ash indicates that deposition occurred ~324,000 to 193,000 years ago during parts of Marine Isotope Stages 9, 7, and 6. Fossil pollen and wood preserved within organic sediments suggest that the composition of the forest altered radically in response to glacial-interglacial climate change. The presence of Podocarpus macrofossils ~1000 meters below the lower limit of their modern distribution indicates a relative cooling of at least 5°C during glacials and persistence of wet conditions. Interglacial deposits contain thermophilic palms suggesting warm and wet climates. Hence, global temperature change can radically alter vegetation communities and biodiversity in this region.

  11. Evaluating the impact of distance measures on deforestation simulations in the fluvial landscapes of amazonia.

    PubMed

    Salonen, Maria; Maeda, Eduardo Eiji; Toivonen, Tuuli

    2014-10-01

    Land use and land cover change (LUCC) models frequently employ different accessibility measures as a proxy for human influence on land change processes. Here, we simulate deforestation in Peruvian Amazonia and evaluate different accessibility measures as LUCC model inputs. We demonstrate how the selection, and different combinations, of accessibility measures impact simulation results. Out of the individual measures, time distance to market center catches the essential aspects of accessibility in our study area. The most accurate simulation is achieved when time distance to market center is used in association with distance to transport network and additional landscape variables. Although traditional Euclidean measures result in clearly lower simulation accuracy when used separately, the combination of two complementary Euclidean measures enhances simulation accuracy significantly. Our results highlight the need for site and context sensitive selection of accessibility variables. More sophisticated accessibility measures can potentially improve LUCC models' spatial accuracy, which often remains low.

  12. Forest Fires in Southwestern Amazonia During 2005: Extent and Distribution in Eastern Acre State, Brazil

    NASA Astrophysics Data System (ADS)

    Brown, I.; Moulard, E. M.; Nakamura, J.; Schroeder, W.; Maldonado, M.; Vasconcelos, S. S.; Selhorst, D.

    2007-05-01

    The extended drought in western Amazonia during 2005 provided the conditions for wild fires that spread in old- growth rain forests and cleared areas of the contiguous areas of Madre de Dios, Peru, Acre, Brazil, and Pando, Bolivia, collectively known as the MAP Region. The greatest extent of the wild fires occurred in eastern Acre State with 60,000 km2 of diverse land uses that range from intensely occupied colonization areas, large cattle ranches, extractive and biological reserves and indigenous areas. At the request of the Public Ministry of Acre and other government agencies we analyzed Landsat 5 and CBERS 2 imagery for forests with canopies affected by fires, using visual interpretation and manual digitalization of polygons. Accuracy assessment was done with 180 aerial photos. The total area of forest with canopies affected by fires was 267,000 ha, roughly five times recent annual deforestation rates for Acre State. Omission and commission errors were 28% and 2%, respectively. Burn scars in non-forest areas were determined using ASTER and CBERS 2 imagery via supervised classification. Total open area with burn scars was 203,000 ha. The total of open area and forests affected by fires exceeded 470,000 ha due to three factors: (1) some images used did not include the last weeks of burning; (2) ground fires in forests that did not affect the canopy and therefore were not detected; and (3) concern of the interpreters to avoid commission errors. Of the twelve municipalities of eastern Acre, most affected were Acrelandia, Placido de Castro, Epitaciolandia with >31%, >19% and >17% of the municipality affected, respectively). The largest impact, >114,000 ha, occurred in the Rio Branco Municipality. Similar patterns of burning occurred in Pando and in Madre de Dios. The environmental, social and economic disaster that these fires produced may be a harbinger of future impacts in southwestern Amazonia if current climate predictions prove to be correct.

  13. Widespread Forest Vertebrate Extinctions Induced by a Mega Hydroelectric Dam in Lowland Amazonia

    PubMed Central

    2015-01-01

    Mega hydropower projects in tropical forests pose a major emergent threat to terrestrial and freshwater biodiversity worldwide. Despite the unprecedented number of existing, under-construction and planned hydroelectric dams in lowland tropical forests, long-term effects on biodiversity have yet to be evaluated. We examine how medium and large-bodied assemblages of terrestrial and arboreal vertebrates (including 35 mammal, bird and tortoise species) responded to the drastic 26-year post-isolation history of archipelagic alteration in landscape structure and habitat quality in a major hydroelectric reservoir of Central Amazonia. The Balbina Hydroelectric Dam inundated 3,129 km2 of primary forests, simultaneously isolating 3,546 land-bridge islands. We conducted intensive biodiversity surveys at 37 of those islands and three adjacent continuous forests using a combination of four survey techniques, and detected strong forest habitat area effects in explaining patterns of vertebrate extinction. Beyond clear area effects, edge-mediated surface fire disturbance was the most important additional driver of species loss, particularly in islands smaller than 10 ha. Based on species-area models, we predict that only 0.7% of all islands now harbor a species-rich vertebrate assemblage consisting of ≥80% of all species. We highlight the colossal erosion in vertebrate diversity driven by a man-made dam and show that the biodiversity impacts of mega dams in lowland tropical forest regions have been severely overlooked. The geopolitical strategy to deploy many more large hydropower infrastructure projects in regions like lowland Amazonia should be urgently reassessed, and we strongly advise that long-term biodiversity impacts should be explicitly included in pre-approval environmental impact assessments. PMID:26132139

  14. Interactions between rainfall, deforestation and fires during recent years in the Brazilian Amazonia.

    PubMed

    Aragão, Luiz Eduardo O C; Malhi, Yadvinder; Barbier, Nicolas; Lima, Andre; Shimabukuro, Yosio; Anderson, Liana; Saatchi, Sassan

    2008-05-27

    Understanding the interplay between climate and land-use dynamics is a fundamental concern for assessing the vulnerability of Amazonia to climate change. In this study, we analyse satellite-derived monthly and annual time series of rainfall, fires and deforestation to explicitly quantify the seasonal patterns and relationships between these three variables, with a particular focus on the Amazonian drought of 2005. Our results demonstrate a marked seasonality with one peak per year for all variables analysed, except deforestation. For the annual cycle, we found correlations above 90% with a time lag between variables. Deforestation and fires reach the highest values three and six months, respectively, after the peak of the rainy season. The cumulative number of hot pixels was linearly related to the size of the area deforested annually from 1998 to 2004 (r2=0.84, p=0.004). During the 2005 drought, the number of hot pixels increased 43% in relation to the expected value for a similar deforested area (approx. 19000km2). We demonstrated that anthropogenic forcing, such as land-use change, is decisive in determining the seasonality and annual patterns of fire occurrence. Moreover, droughts can significantly increase the number of fires in the region even with decreased deforestation rates. We may expect that the ongoing deforestation, currently based on slash and burn procedures, and the use of fires for land management in Amazonia will intensify the impact of droughts associated with natural climate variability or human-induced climate change and, therefore, a large area of forest edge will be under increased risk of fires.

  15. Genetic structure of traditional varieties of bitter manioc in three soils in Central Amazonia.

    PubMed

    Alves-Pereira, Alessandro; Peroni, Nivaldo; Abreu, Aluana Gonçalves; Gribel, Rogério; Clement, Charles R

    2011-10-01

    Manioc is the most important food crop that originated in Amazonia. Many studies have increased our understanding of its evolutionary dynamics under cultivation. However, most of them focused on manioc cultivation in environments with low soil fertility, generally Oxisols. Recent ethnobotanical observations showed that bitter manioc also performs well in high fertility soils, such as Amazonian dark earths (ADE) and the floodplain. We used 10 microsatellite loci to investigate the genetic diversity and structure of bitter manioc varieties grown in different soil types in communities of smallholder farmers along the middle Madeira River in Central Amazonia. The genetic diversity of some sweet varieties and seedlings was also evaluated. Adult individuals showed higher levels of genetic diversity and smaller inbreeding coefficients (A ( R ) = 5.52, H ( O ) = 0.576, f = 0.086) than seedlings (A ( R ) = 4.39, H ( O ) = 0.421, f = 0.242). Bitter manioc varieties from the floodplain showed higher levels of genetic diversity (A ( R ) = 5.19, H ( O ) = 0.606) than those from ADE (A ( R ) = 4.45, H ( O ) = 0.538) and from Oxisols (A ( R ) = 4.15, H ( O ) = 0.559). The varieties grown in the floodplain were strongly differentiated from the varieties grown in Oxisols (F ( ST ) = 0.093) and ADE (F ( ST ) = 0.108), suggesting important genetic structuring among varieties grown in the floodplain and upland soils (ADE and Oxisols). This is the first time that genetic divergence of bitter manioc varieties in cultivation in different Amazonian soils in a small geographic area is reported.

  16. Helminth fauna of chiropterans in Amazonia: biological interactions between parasite and host.

    PubMed

    de Albuquerque, Ana Cláudia Alexandre; Moraes, Marcela Figueiredo Duarte; Silva, Ana Carolina; Lapera, Ivan Moura; Tebaldi, José Hairton; Lux Hoppe, Estevam G

    2016-08-01

    Amazonia, the largest Brazilian biome, is one of the most diverse biomes around the world. Considering the Brazilian chiropteran species, 120 out of known 167 species are registered in Pará state, with 10 endemic species. Despite the high diversity of bats in Amazonia, studies on their parasites, especially on helminths, are scarce. Therefore, the present study aims to study the helminth fauna of different bats from the Pará state, Amazon biome, determine the descriptors of infection, and evaluate the host-parasite interactions, as well as evaluate differences in ecological indexes in accordance with the feeding guilds. The study was developed on 67 bats of 21 species captured in several areas of the Pará state. The animals were identified, divided into feeding guilds, and necropsied. The parasites obtained were identified and quantified. A total of 182 parasites were found in 20.89 % of the studied bats, representing nine species, as follows: Anenterotrema eduardocaballeroi, Anenterotrema liliputianum, Ochoterenatrema caballeroi, Tricholeiperia sp., Parahistiostrongylus octacanthus, Litomosoides guiterasi, Litomosoides brasiliensis, Capillariinae gen. sp., and Hymenolepididae gen. sp. Also, the results indicated that there was no impact of parasitism on host body condition and no relationship between sex and parasite intensity. In relation to the feeding guilds, the omnivores showed higher prevalence and mean intensity. Animals from regions closer to the equator tend to have greater richness in parasite species, but the present study revealed low diversity and richness in species. In conclusion, the ecological pattern observed for other animal groups, in which higher parasitic diversity are registered in lower latitudes, is not applicable to chiropterans from the study area.

  17. Widespread Forest Vertebrate Extinctions Induced by a Mega Hydroelectric Dam in Lowland Amazonia.

    PubMed

    Benchimol, Maíra; Peres, Carlos A

    2015-01-01

    Mega hydropower projects in tropical forests pose a major emergent threat to terrestrial and freshwater biodiversity worldwide. Despite the unprecedented number of existing, under-construction and planned hydroelectric dams in lowland tropical forests, long-term effects on biodiversity have yet to be evaluated. We examine how medium and large-bodied assemblages of terrestrial and arboreal vertebrates (including 35 mammal, bird and tortoise species) responded to the drastic 26-year post-isolation history of archipelagic alteration in landscape structure and habitat quality in a major hydroelectric reservoir of Central Amazonia. The Balbina Hydroelectric Dam inundated 3,129 km2 of primary forests, simultaneously isolating 3,546 land-bridge islands. We conducted intensive biodiversity surveys at 37 of those islands and three adjacent continuous forests using a combination of four survey techniques, and detected strong forest habitat area effects in explaining patterns of vertebrate extinction. Beyond clear area effects, edge-mediated surface fire disturbance was the most important additional driver of species loss, particularly in islands smaller than 10 ha. Based on species-area models, we predict that only 0.7% of all islands now harbor a species-rich vertebrate assemblage consisting of ≥80% of all species. We highlight the colossal erosion in vertebrate diversity driven by a man-made dam and show that the biodiversity impacts of mega dams in lowland tropical forest regions have been severely overlooked. The geopolitical strategy to deploy many more large hydropower infrastructure projects in regions like lowland Amazonia should be urgently reassessed, and we strongly advise that long-term biodiversity impacts should be explicitly included in pre-approval environmental impact assessments.

  18. Atmospheric aerosols in Amazonia and land use change: from natural biogenic to biomass burning conditions.

    PubMed

    Artaxo, Paulo; Rizzo, Luciana V; Brito, Joel F; Barbosa, Henrique M J; Arana, Andrea; Sena, Elisa T; Cirino, Glauber G; Bastos, Wanderlei; Martin, Scot T; Andreae, Meinrat O

    2013-01-01

    In the wet season, a large portion of the Amazon region constitutes one of the most pristine continental areas, with very low concentrations of atmospheric trace gases and aerosol particles. However, land use change modifies the biosphere-atmosphere interactions in such a way that key processes that maintain the functioning of Amazonia are substantially altered. This study presents a comparison between aerosol properties observed at a preserved forest site in Central Amazonia (TT34 North of Manaus) and at a heavily biomass burning impacted site in south-western Amazonia (PVH, close to Porto Velho). Amazonian aerosols were characterized in detail, including aerosol size distributions, aerosol light absorption and scattering, optical depth and aerosol inorganic and organic composition, among other properties. The central Amazonia site (TT34) showed low aerosol concentrations (PM2.5 of 1.3 +/- 0.7 microg m(-3) and 3.4 +/- 2.0 microg m(-3) in the wet and dry seasons, respectively), with a median particle number concentration of 220 cm(-3) in the wet season and 2200 cm(-3) in the dry season. At the impacted site (PVH), aerosol loadings were one order of magnitude higher (PM2.5 of 10.2 +/- 9.0 microg m(-3) and 33.0 +/- 36.0 microg m(-3) in the wet and dry seasons, respectively). The aerosol number concentration at the impacted site ranged from 680 cm(-3) in the wet season up to 20 000 cm(-3) in the dry season. An aerosol chemical speciation monitor (ACSM) was deployed in 2013 at both sites, and it shows that organic aerosol account to 81% to the non-refractory PM1 aerosol loading at TT34, while biomass burning aerosols at PVH shows a 93% content of organic particles. Three years of filter-based elemental composition measurements shows that sulphate at the impacted site decreases, on average, from 12% of PM2.5 mass during the wet season to 5% in the dry season. This result corroborates the ACSM finding that the biomass burning contributed overwhelmingly to the organic

  19. OBRA: a European project to create an observatory for long-term governance on radioactive waste management

    SciTech Connect

    Martell, Meritxell; Duro, Lara; Bruno, Jordi; Kopetz, Irene

    2007-07-01

    Available in abstract form only. Full text of publication follows: This paper introduces a number of topics that will be addressed by the 'OBRA' project. The OBRA project (2006-2008) is a 2-year Coordination Action under the 6. EURATOM Framework Program (FP) which started on 1. November 2006 and will finish on 31. October 2008. The project aims to assess the feasibility of creating an Observatory for Long-term Governance on Radioactive Waste Management in Europe. OBRA will devise an Observatory to promote appropriate forms of interaction between stakeholders, mainly local and regional communities and experts. The focus and value of OBRA lies on the development of a concrete tool to promote governance processes. With respect to this objective, the paper introduces the project and some of the key questions that have been addressed in the first creative workshop and which will be the focus of OBRA in the following months. (authors)

  20. Biogeographic and diversification patterns of Neotropical Troidini butterflies (Papilionidae) support a museum model of diversity dynamics for Amazonia

    PubMed Central

    2012-01-01

    Background The temporal and geographical diversification of Neotropical insects remains poorly understood because of the complex changes in geological and climatic conditions that occurred during the Cenozoic. To better understand extant patterns in Neotropical biodiversity, we investigated the evolutionary history of three Neotropical swallowtail Troidini genera (Papilionidae). First, DNA-based species delimitation analyses were conducted to assess species boundaries within Neotropical Troidini using an enlarged fragment of the standard barcode gene. Molecularly delineated species were then used to infer a time-calibrated species-level phylogeny based on a three-gene dataset and Bayesian dating analyses. The corresponding chronogram was used to explore their temporal and geographical diversification through distinct likelihood-based methods. Results The phylogeny for Neotropical Troidini was well resolved and strongly supported. Molecular dating and biogeographic analyses indicate that the extant lineages of Neotropical Troidini have a late Eocene (33–42 Ma) origin in North America. Two independent lineages (Battus and Euryades + Parides) reached South America via the GAARlandia temporary connection, and later became extinct in North America. They only began substantive diversification during the early Miocene in Amazonia. Macroevolutionary analysis supports the “museum model” of diversification, rather than Pleistocene refugia, as the best explanation for the diversification of these lineages. Conclusions This study demonstrates that: (i) current Neotropical biodiversity may have originated ex situ; (ii) the GAARlandia bridge was important in facilitating invasions of South America; (iii) colonization of Amazonia initiated the crown diversification of these swallowtails; and (iv) Amazonia is not only a species-rich region but also acted as a sanctuary for the dynamics of this diversity. In particular, Amazonia probably allowed the persistence of old

  1. Ostracods (Crustacea) and their palaeoenvironmental implication for the Solimões Formation (Late Miocene; Western Amazonia/Brazil)

    PubMed Central

    Gross, Martin; Ramos, Maria Ines; Caporaletti, Marco; Piller, Werner E.

    2013-01-01

    Western Amazonia's landscape and biota were shaped by an enormous wetland during the Miocene epoch. Among the most discussed topics of this ecosystem range the question on the transitory influx of marine waters. Inter alia the occurrence of typically brackish water associated ostracods is repeatedly consulted to infer elevated salinities or even marine ingressions. The taxonomical investigation of ostracod faunas derived from the upper part of the Solimões Formation (Eirunepé; W-Brazil) documents a moderately diverse assemblage (19 species). A wealth of freshwater ostracods (mainly Cytheridella, Penthesilenula) was found co-occurring with taxa (chiefly Cyprideis) usually related to marginal marine settings today. The observed faunal compositions as well as constantly very light δ18O- and δ13C-values obtained by measuring both, the freshwater and brackish water ostracod group, refer to entirely freshwater conditions. These results corroborate with previous sedimentological and palaeontological observations, which proposed a fluvial depositional system for this part of western Amazonia during the Late Miocene. We demonstrate that some endemic, “brackish” water ostracods (i.e., Cyprideis) have been effectively adapted to freshwater conditions. Thus, their occurrence is no univocal evidence for the influence of brackish or marine waters in western Amazonia during the Miocene. PMID:26523090

  2. Maximizing Amazonia's Ecosystem Services: Juggling the potential for carbon storage, agricultural yield and biodiversity in the Amazon

    NASA Astrophysics Data System (ADS)

    O'Connell, C. S.; Foley, J. A.; Gerber, J. S.; Polasky, S.

    2011-12-01

    The Amazon is not only an exceptionally biodiverse and carbon-rich tract of tropical forest, it is also a case study in land use change. Over the next forty years it will continue to experience pressure from an urbanizing and increasingly affluent populace: under a business-as-usual scenario, global cropland, pasture and biofuels systems will carry on expanding, while the Amazon's carbon storage potential will likely become another viable revenue source under REDD+. Balancing those competing land use pressures ought also take into account Amazonia's high - but heterogeneous - biodiversity. Knowing where Amazonia has opportunities to make efficient or optimal trade offs between carbon storage, agricultural production and biodiversity can allow policymakers to direct or influence LUC drivers. This analysis uses a spatially-explicit model that takes climate and management into account to quantify the potential agricultural yield of both the Amazon's most important agricultural commodities - sugar, soy and maize - as well as several that are going to come into increasing prominence, including palm oil. In addition, it maps the potential for carbon to be stored in forest biomass and relative species richness across Amazonia. We then compare carbon storage, agricultural yield and species richness and identify areas where efficient trade offs occur between food, carbon, and biodiversity - three critical ecosystem goods and services provided by the world's largest tropical forest.

  3. Ostracods (Crustacea) and their palaeoenvironmental implication for the Solimões Formation (Late Miocene; Western Amazonia/Brazil).

    PubMed

    Gross, Martin; Ramos, Maria Ines; Caporaletti, Marco; Piller, Werner E

    2013-03-01

    Western Amazonia's landscape and biota were shaped by an enormous wetland during the Miocene epoch. Among the most discussed topics of this ecosystem range the question on the transitory influx of marine waters. Inter alia the occurrence of typically brackish water associated ostracods is repeatedly consulted to infer elevated salinities or even marine ingressions. The taxonomical investigation of ostracod faunas derived from the upper part of the Solimões Formation (Eirunepé; W-Brazil) documents a moderately diverse assemblage (19 species). A wealth of freshwater ostracods (mainly Cytheridella, Penthesilenula) was found co-occurring with taxa (chiefly Cyprideis) usually related to marginal marine settings today. The observed faunal compositions as well as constantly very light δ(18)O- and δ(13)C-values obtained by measuring both, the freshwater and brackish water ostracod group, refer to entirely freshwater conditions. These results corroborate with previous sedimentological and palaeontological observations, which proposed a fluvial depositional system for this part of western Amazonia during the Late Miocene. We demonstrate that some endemic, "brackish" water ostracods (i.e., Cyprideis) have been effectively adapted to freshwater conditions. Thus, their occurrence is no univocal evidence for the influence of brackish or marine waters in western Amazonia during the Miocene.

  4. Impact of mixing state and hygroscopicity on CCN activity of biomass burning aerosol in Amazonia

    NASA Astrophysics Data System (ADS)

    Sánchez Gácita, Madeleine; Longo, Karla M.; Freire, Julliana L. M.; Freitas, Saulo R.; Martin, Scot T.

    2017-02-01

    Smoke aerosols prevail throughout Amazonia because of widespread biomass burning during the dry season, and external mixing, low variability in the particle size distribution and low particle hygroscopicity are typical. There can be profound effects on cloud properties. This study uses an adiabatic cloud model to simulate the activation of smoke particles as cloud condensation nuclei (CCN) for three hypothetical case studies, chosen as to resemble biomass burning aerosol observations in Amazonia. The relative importance of variability in hygroscopicity, mixing state, and activation kinetics for the activated fraction and maximum supersaturation is assessed. For a population with κp = 0.04, an overestimation of the cloud droplet number concentration Nd for the three selected case studies between 22.4 ± 1.4 and 54.3 ± 3.7 % was obtained when assuming a hygroscopicity parameter κp = 0.20. Assuming internal mixing of the aerosol population led to overestimations of up to 20 % of Nd when a group of particles with medium hygroscopicity was present in the externally mixed population cases. However, the overestimations were below 10 % for external mixtures between very low and low-hygroscopicity particles, as seems to be the case for Amazon smoke particles. Kinetic limitations were significant for medium- and high-hygroscopicity particles, and much lower for very low and low-hygroscopicity particles. When particles were assumed to be at equilibrium and to respond instantly to changes in the air parcel supersaturation, the overestimation of the droplet concentration was up to ˜ 100 % in internally mixed populations, and up to ˜ 250 % in externally mixed ones, being larger for the higher values of hygroscopicity. In addition, a perceptible delay between the times when maximum supersaturation and maximum aerosol activated fraction are reached was noticed and, for aerosol populations with effective hygroscopicity κpeff higher than a certain threshold value, the delay in

  5. A phylogenetic lineage of closely related trypanosomes (Trypanosomatidae, Kinetoplastida) of anurans and sand flies (Psychodidae, Diptera) sharing the same ecotopes in brazilian amazonia.

    PubMed

    Ferreira, Robson C; De Souza, Adelson A; Freitas, Rui A; Campaner, Marta; Takata, Carmem S A; Barrett, Toby V; Shaw, Jeffrey J; Teixeira, Marta M G

    2008-01-01

    Analysis of the phylogenetic relationships among trypanosomes from vertebrates and invertebrates disclosed a new lineage of trypanosomes circulating among anurans and sand flies that share the same ecotopes in Brazilian Amazonia. This assemblage of closely related trypanosomes was determined by comparing whole SSU rDNA sequences of anuran trypanosomes from the Brazilian biomes of Amazonia, the Pantanal, and the Atlantic Forest and from Europe, North America, and Africa, and from trypanosomes of sand flies from Amazonia. Phylogenetic trees based on maximum likelihood and parsimony corroborated the positioning of all new anuran trypanosomes in the aquatic clade but did not support the monophyly of anuran trypanosomes. However, all analyses always supported four major clades (An01-04) of anuran trypanosomes. Clade An04 is composed of trypanosomes from exotic anurans. Isolates in clades An01 and An02 were from Brazilian frogs and toads captured in the three biomes studied, Amazonia, the Pantanal and the Atlantic Forest. Clade An01 contains mostly isolates from Hylidae whereas clade An02 comprises mostly isolates from Bufonidae; and clade An03 contains trypanosomes from sand flies and anurans of Bufonidae, Leptodactylidae, and Leiuperidae exclusively from Amazonia. To our knowledge, this is the first study describing morphological and growth features, and molecular phylogenetic affiliation of trypanosomes from anurans and phlebotomines, incriminating these flies as invertebrate hosts and probably also as important vectors of Amazonian terrestrial anuran trypanosomes.

  6. Saharan dust in Brazil and Suriname during the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) - Cooperative LBA Regional Experiment (CLAIRE) in March 1998

    NASA Astrophysics Data System (ADS)

    Formenti, P.; Andreae, M. O.; Lange, L.; Roberts, G.; Cafmeyer, J.; Rajta, I.; Maenhaut, W.; Holben, B. N.; Artaxo, P.; Lelieveld, J.

    2001-07-01

    Advection of Saharan dust was observed via chemical and optical measurements during March 1998 in Brazil and Suriname during the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA)-Cooperative LBA Airborne Regional Experiment (CLAIRE)-98 experiment. In Brazil the dust outbreak produced an increase of a factor of 3 in the daily mean mass concentration (up to 26±7 μg m-3) of particles smaller than 10 μm equivalent aerodynamic diameter (EAD), and in the daily mean aerosol particle scattering coefficient σs (up to 26±8 Mm-1 STP, ambient humidity). Background levels of aerosol scattering (ambient) were σs ˜ 10 Mm-1. The effect of dust advection was evident for all major crustal elements (Al, Si, Ca, Ti, Mn, and Fe), as well as the sea-salt elements (Na, Cl, and S), as the dust layer was transported at low altitude (below 800 hPa). Coarse P and organic carbon (OC) concentrations were not influenced by the occurrence of dust, and were mainly emitted by the rain forest. The dry scattering mass efficiency of dust (particles smaller than 10 μm EAD) was estimated to be between 0.65 (±0.06) and 0.89 (±0.08) m2 g-1. Airborne profiles of aerosol scattering showed two distinct types of vertical structure in the dust layer over Suriname, either vertically uniform (15, 26 March), or plume-like (25 March). Dust layers extended generally up to 700 hPa, while scattering layers occasionally encountered at higher altitudes resulted from smoke emitted by biomass burning in Venezuela and Colombia. Observations in South America were supported by measurements in Israel and Tenerife (Canary Islands), where the dust outbreaks were also detected.

  7. Extreme seasonal droughts and floods in Amazonia: causes, trends and impacts

    NASA Astrophysics Data System (ADS)

    Marengo, J. A.

    2015-12-01

    J. A. Marengo * and J. C. Espinoza** * Centro Nacional de Monitoramento e Alerta de Desastres Naturais, Ministério da Ciência, Tecnologia e Inovação, Sao Paulo, Brazil ** Subdirección de Ciencias de la Atmósfera e Hidrósfera (SCAH), Instituto Geofísico del Perú, Lima, Peru This paper reviews recent progress in the study and understanding of extreme seasonal events in the Amazon region, focusing on drought and floods. The review includes a history of droughts and floods in the past, in the present and some discussions on future extremes in the context of climate change and its impacts on the Amazon region. Several extreme hydrological events, some of them characterized as 'once in a century', have been reported in the Amazon region during the last decade. While abundant rainfall in various sectors of the basin has determined extreme floods along the river's main stem in 1953, 1989, 1999, 2009, 2012-2015, deficient rainfall in 1912, 1926, 1963, 1980, 1983, 1995, 1997, 1998, 2005 and 2010 has caused anomalously low river levels, and an increase in the risk and number of fires in the region, with consequences for humans. This is consistent with changes in the variability of the hydrometeorology of the basin and suggests that extreme hydrological events have been more frequent in the last two decades. Some of these intense/reduced rainfalls and subsequent floods/droughts were associated (but not exclusively) with La Niña/El Niño events. In addition, moisture transport anomalies from the tropical Atlantic into Amazonia, and from northern to southern Amazonia alter the water cycle in the region year-to-year. We also assess the impacts of such extremes on natural and human systems in the region, considering ecological, economic and societal impacts in urban and rural areas, particularly during the recent decades. In the context of the future climate change, studies show a large range of uncertainty, but suggest that drought might intensify through the 21st

  8. Simulation of deforestation in eastern Amazonia using a high-resolution model

    NASA Astrophysics Data System (ADS)

    Gandu, A. W.; Cohen, J. C. P.; de Souza, J. R. S.

    This work evaluates the impact of deforestation on the climate of the eastern portion of the Amazon basin. This region is primarily an area of native tropical rainforest, but also contains several other natural ecosystems such as mangroves and savanna. It is the most densely populated area in Amazonia, and has been significantly affected by deforestation. In this study, numerical simulations were performed with a high spatial resolution, regional model that allows for consideration of mesoscale aspects such as topography, coastlines and large rivers. To evaluate the present situation and to predict potential future effects of deforestation on the climatic conditions of this region, two, one-year model simulations were made. In the first, ``control simulation'', an attempt was made to match the existing surface vegetation. The biophysical parameters used were derived from recent studies of similar Amazon-region ecosystems. In the second run, ``deforested simulation'', the forested-area biophysical parameters were replaced by those corresponding to the pasture areas of the region. The higher-resolution regional modelling revealed important climatic 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 cloud cover and precipitation. However, increased cloud cover and precipitation was predicted over upland areas, especially on slopes facing river valleys. The modelled surface sensible and latent heat fluxes also presented both positive and negative anomalies. The magnitudes of these anomalies were greater during the dry season. Windspeed near the surface was the meteorological variable that presented the most significant change due to deforestation. The reduction in roughness coefficient resulting from the shift from forest to pasture produced increased windspeeds near the

  9. Geographic distribution and demography of Pithecia aequatorialis (pitheciidae) in Peruvian Amazonia.

    PubMed

    Aquino, Rolando; Cornejo, Fanny M; Pezo Lozano, Etersit; Heymann, Eckhard W

    2009-12-01

    To study the geographic distribution and demographic characteristics of Pithecia aequatorialis in Peruvian Amazonia, we undertook surveys and transect census in three river basins (Río Itaya, Río Tigre and Río Curaray) between 2004 and 2008. A total of 123 groups of P. aequatorialis was encountered during 1623 km of transect walks. Group size was uniform among the three areas (3.4-3.6 individuals), but surprisingly, population densities were higher in the area with strong hunting pressure (Río Itaya: 7.8 ind./km(2), vs. 5.6 and 5.9 km(2) in the Río Tigre and Río Curaray basins, respectively). The most common group composition included an adult pair with one offspring. Groups with more than one adult male and/or female accounted for 35% of sightings. Our observations extend P. aequatorialis range in Peru further south to the area between the Río Tigre and Río Corrientes, but exclude the area to the north between the Río Curaray and Río Napo. These findings are in contrast to previous distribution maps. P. aequatorialis was rarely seen in interspecific association during our censuses.

  10. Molecular phylogeny and morphometric analyses reveal deep divergence between Amazonia and Atlantic Forest species of Dendrophryniscus.

    PubMed

    Fouquet, Antoine; Recoder, Renato; Teixeira, Mauro; Cassimiro, José; Amaro, Renata Cecília; Camacho, Agustín; Damasceno, Roberta; Carnaval, Ana Carolina; Moritz, Craig; Rodrigues, Miguel Trefaut

    2012-03-01

    Dendrophryniscus is an early diverging clade of bufonids represented by few small-bodied species distributed in Amazonia and the Atlantic Forest. We used mitochondrial (414 bp of 12S, 575 bp of 16S genes) and nuclear DNA (785 bp of RAG-1) to investigate phylogenetic relationships and the timing of diversification within the genus. These molecular data were gathered from 23 specimens from 19 populations, including eight out of the 10 nominal species of the genus as well as Rhinella boulengeri. Analyses also included sequences of representatives of 18 other bufonid genera that were publically available. We also examined morphological characters to analyze differences within Dendrophryniscus. We found deep genetic divergence between an Amazonian and an Atlantic Forest clade, dating back to Eocene. Morphological data corroborate this distinction. We thus propose to assign the Amazonian species to a new genus, Amazonella. The species currently named R. boulengeri, which has been previously assigned to the genus Rhamphophryne, is shown to be closely related to Dendrophryniscus species. Our findings illustrate cryptic trends in bufonid morphological evolution, and point to a deep history of persistence and diversification within the Amazonian and Atlantic rainforests. We discuss our results in light of available paleoecological data and the biogeographic patterns observed in other similarly distributed groups.

  11. Microbial diversity of an anoxic zone of a hydroelectric power station reservoir in Brazilian Amazonia.

    PubMed

    Graças, Diego A; Miranda, Paulo R; Baraúna, Rafael A; McCulloch, John A; Ghilardi, Rubens; Schneider, Maria Paula C; Silva, Artur

    2011-11-01

    Microbial diversity was evaluated in an anoxic zone of Tucuruí Hydroelectric Power Station reservoir in Brazilian Amazonia using a culture-independent approach by amplifying and sequencing fragments of the 16S rRNA gene using metagenomic DNA as a template. Samples obtained from the photic, aphotic (40 m) and sediment (60 m) layers were used to construct six 16S rDNA libraries containing a total of 1,152 clones. The sediment, aphotic and photic layers presented 64, 33 and 35 unique archaeal operational taxonomic units (OTUs). The estimated richness of these layers was evaluated to be 153, 106 and 79 archaeal OTUs, respectively, using the abundance-based coverage estimator (ACE) and 114, 83 and 77 OTUs using the Chao1 estimator. For bacterial sequences, 114, 69 and 57 OTUs were found in the sediment, aphotic and photic layers, which presented estimated richnesses of 1,414, 522 and 197 OTUs (ACE) and 1,059, 1,014 and 148 OTUs (Chao1), respectively. Phylogenetic analyses of the sequences obtained revealed a high richness of microorganisms which participate in the carbon cycle, namely, methanogenic archaea and methanotrophic proteobacteria. Most sequences obtained belong to non-culturable prokaryotes. The present study offers the first glimpse of the huge microbial diversity of an anoxic area of a man-made lacustrine environment in the tropics.

  12. Empty forest or empty rivers? A century of commercial hunting in Amazonia.

    PubMed

    Antunes, André P; Fewster, Rachel M; Venticinque, Eduardo M; Peres, Carlos A; Levi, Taal; Rohe, Fabio; Shepard, Glenn H

    2016-10-01

    The Amazon basin is the largest and most species-rich tropical forest and river system in the world, playing a pivotal role in global climate regulation and harboring hundreds of traditional and indigenous cultures. It is a matter of intense debate whether the ecosystem is threatened by hunting practices, whereby an "empty forest" loses critical ecological functions. Strikingly, no previous study has examined Amazonian ecosystem resilience through the perspective of the massive 20th century international trade in furs and skins. We present the first historical account of the scale and impacts of this trade and show that whereas aquatic species suffered basin-wide population collapse, terrestrial species did not. We link this differential resilience to the persistence of adequate spatial refuges for terrestrial species, enabling populations to be sustained through source-sink dynamics, contrasting with unremitting hunting pressure on more accessible aquatic habitats. Our findings attest the high vulnerability of aquatic fauna to unregulated hunting, particularly during years of severe drought. We propose that the relative resilience of terrestrial species suggests a marked opportunity for managing, rather than criminalizing, contemporary traditional subsistence hunting in Amazonia, through both the engagement of local people in community-based comanagement programs and science-led conservation governance.

  13. Regional-Scale Drivers of Forest Structure and Function in Northwestern Amazonia

    PubMed Central

    Higgins, Mark A.; Asner, Gregory P.; Anderson, Christopher B.; Martin, Roberta E.; Knapp, David E.; Tupayachi, Raul; Perez, Eneas; Elespuru, Nydia; Alonso, Alfonso

    2015-01-01

    Field studies in Amazonia have found a relationship at continental scales between soil fertility and broad trends in forest structure and function. Little is known at regional scales, however, about how discrete patterns in forest structure or functional attributes map onto underlying edaphic or geological patterns. We collected airborne LiDAR (Light Detection and Ranging) data and VSWIR (Visible to Shortwave Infrared) imaging spectroscopy measurements over 600 km2 of northwestern Amazonian lowland forests. We also established 83 inventories of plant species composition and soil properties, distributed between two widespread geological formations. Using these data, we mapped forest structure and canopy reflectance, and compared them to patterns in plant species composition, soils, and underlying geology. We found that variations in soils and species composition explained up to 70% of variation in canopy height, and corresponded to profound changes in forest vertical profiles. We further found that soils and plant species composition explained more than 90% of the variation in canopy reflectance as measured by imaging spectroscopy, indicating edaphic and compositional control of canopy chemical properties. We last found that soils explained between 30% and 70% of the variation in gap frequency in these forests, depending on the height threshold used to define gaps. Our findings indicate that a relatively small number of edaphic and compositional variables, corresponding to underlying geology, may be responsible for variations in canopy structure and chemistry over large expanses of Amazonian forest. PMID:25793602

  14. Empty forest or empty rivers? A century of commercial hunting in Amazonia

    PubMed Central

    Antunes, André P.; Fewster, Rachel M.; Venticinque, Eduardo M.; Peres, Carlos A.; Levi, Taal; Rohe, Fabio; Shepard, Glenn H.

    2016-01-01

    The Amazon basin is the largest and most species-rich tropical forest and river system in the world, playing a pivotal role in global climate regulation and harboring hundreds of traditional and indigenous cultures. It is a matter of intense debate whether the ecosystem is threatened by hunting practices, whereby an “empty forest” loses critical ecological functions. Strikingly, no previous study has examined Amazonian ecosystem resilience through the perspective of the massive 20th century international trade in furs and skins. We present the first historical account of the scale and impacts of this trade and show that whereas aquatic species suffered basin-wide population collapse, terrestrial species did not. We link this differential resilience to the persistence of adequate spatial refuges for terrestrial species, enabling populations to be sustained through source-sink dynamics, contrasting with unremitting hunting pressure on more accessible aquatic habitats. Our findings attest the high vulnerability of aquatic fauna to unregulated hunting, particularly during years of severe drought. We propose that the relative resilience of terrestrial species suggests a marked opportunity for managing, rather than criminalizing, contemporary traditional subsistence hunting in Amazonia, through both the engagement of local people in community-based comanagement programs and science-led conservation governance. PMID:27757421

  15. Temporal Scales of the Nocturnal Flow Within and Above a Forest Canopy in Amazonia

    NASA Astrophysics Data System (ADS)

    Santos, Daniel M.; Acevedo, Otávio C.; Chamecki, Marcelo; Fuentes, José D.; Gerken, Tobias; Stoy, Paul C.

    2016-10-01

    Multiresolution decomposition is applied to 10 months of nocturnal turbulence observations taken at eight levels within and above a forest canopy in Central Amazonia. The aim is to identify the contributions of different temporal scales of the flow above and within the canopy. Results show that turbulence intensity in the lower canopy is mostly affected by the static stability in the upper canopy. Horizontal velocity fluctuations peak at time scales longer than 100 s within the canopy, which correspond to the scale of non-turbulent submeso motions above the canopy. In the vertical velocity spectrum near the surface, the peak occurs at time scales around 100 s, which are larger than the time scales of the turbulent flow above the canopy. Heat-flux cospectra within the canopy peak at the same temporal scales as the vertical velocity fluctuations at that level, suggesting the existence of buoyancy driven turbulence. Case studies are presented as evidence that low-frequency fluctuations propagate towards the canopy interior more easily than does turbulence.

  16. Lipid Oxidation Inhibitory Effects and Phenolic Composition of Aqueous Extracts from Medicinal Plants of Colombian Amazonia

    PubMed Central

    Lizcano, Leandro J.; Viloria-Bernal, María; Vicente, Francisca; Berrueta, Luis Angel; Gallo, Blanca; Martínez-Cañamero, Magdalena; Ruiz-Larrea, Maria Begoña; Ruiz-Sanz, José Ignacio

    2012-01-01

    Diverse plants of ethnobotanic interest in Amazonia are commonly used in traditional medicine. We determined the antioxidant potential against lipid peroxidation, the antimicrobial activity, and the polyphenol composition of several Amazonian plants (Brownea rosademonte, Piper glandulosissimum, Piper krukoffii, Piper putumayoense, Solanum grandiflorum, and Vismia baccifera). Extracts from the plant leaf, bark, and stem were prepared as aqueous infusions, as used in folk medicine, and added to rat liver microsomes exposed to iron. The polyphenolic composition was detected by reverse-phase HPLC coupled to diode-array detector and MS/MS analysis. The antimicrobial activity was tested by the spot-on-a-lawn method against several indicator microorganisms. All the extracts inhibited lipid oxidation, except the P. glandulosissimum stem. The plant extracts exhibiting high antioxidant potential (V. baccifera and B. rosademonte) contained high levels of flavanols (particularly, catechin and epicatechin). By contrast, S. grandiflorum leaf, which exhibited very low antioxidant activity, was rich in hydroxycinnamic acids. None of the extracts showed antimicrobial activity. This study demonstrates for the first time the presence of bioactive polyphenolic compounds in several Amazonian plants, and highlights the importance of flavanols as major phenolic contributors to antioxidant activity. PMID:22754307

  17. Megafans and Trumpeter Bird Biodiversity-Psophia Phylogeography and Landscape Evolution in Amazonia

    NASA Technical Reports Server (NTRS)

    Wilkinson, Justin

    2014-01-01

    Based on geomorphic character and mapped geology, geologists have interpreted the landscape surrounding the Andes Mountains as becoming progressively younger to the East. These sedimentary materials filled the late Miocene swampland that formerly occupied central and western Amazonia. Apart from the ancient landscapes of the Guiana Highlands (top right, figure 1a), Zone Ac is the oldest, followed by Zone Aw, within which megafan Jw is older than megafan Je (figure 1a). DNA-based paleogeography of the trumpeters shows that younger clades diverge from parent lineages with increasing distance from the Andes chain. Thus, Psophia napensis diverges from the P. crepitans parent, and P. ochroptera diverges from P. napensis. The P. ochroptera population is confined solely to the Je megafan (figure 1a). The same trend is seen on the south side of the Amazon depression. Since the timing of the events seems to be of exactly the same order [post-Miocene for the land surfaces and trumpeter divergence within the last 3 million years (figure 1d)], it seems reasonable to think that the megafans provided the substrate on which new bird lineages could speciate. Such physical controls of evolution are becoming more important in the understanding of biodiversity.

  18. Environmental Costs of Government-Sponsored Agrarian Settlements in Brazilian Amazonia

    PubMed Central

    2015-01-01

    Brazil has presided over the most comprehensive agrarian reform frontier colonization program on Earth, in which ~1.2 million settlers have been translocated by successive governments since the 1970’s, mostly into forested hinterlands of Brazilian Amazonia. These settlements encompass 5.3% of this ~5 million km2 region, but have contributed with 13.5% of all land conversion into agropastoral land uses. The Brazilian Federal Agrarian Agency (INCRA) has repeatedly claimed that deforestation in these areas largely predates the sanctioned arrival of new settlers. Here, we quantify rates of natural vegetation conversion across 1911 agrarian settlements allocated to 568 Amazonian counties and compare fire incidence and deforestation rates before and after the official occupation of settlements by migrant farmers. The timing and spatial distribution of deforestation and fires in our analysis provides irrefutable chronological and spatially explicit evidence of agropastoral conversion both inside and immediately outside agrarian settlements over the last decade. Deforestation rates are strongly related to local human population density and road access to regional markets. Agrarian settlements consistently accelerated rates of deforestation and fires, compared to neighboring areas outside settlements, but within the same counties. Relocated smallholders allocated to forest areas undoubtedly operate as pivotal agents of deforestation, and most of the forest clearance occurs in the aftermath of government-induced migration. PMID:26247467

  19. Patterns of orchid bee species diversity and turnover among forested plateaus of central Amazonia.

    PubMed

    Antonini, Yasmine; Machado, Carolina de Barros; Galetti, Pedro Manoel; Oliveira, Marcio; Dirzo, Rodolfo; Fernandes, Geraldo Wilson

    2017-01-01

    The knowledge of spatial pattern and geographic beta-diversity is of great importance for biodiversity conservation and interpreting ecological information. Tropical forests, especially the Amazon Rainforest, are well known for their high species richness and low similarity in species composition between sites, both at local and regional scales. We aimed to determine the effect and relative importance of area, isolation and climate on species richness and turnover in orchid bee assemblages among plateaus in central Brazilian Amazonia. Variance partitioning techniques were applied to assess the relative effects of spatial and environmental variables on bee species richness, phylogeny and composition. We hypothesized that greater abundance and richness of orchid bees would be found on larger plateaus, with a set of core species occurring on all of them. We also hypothesized that smaller plateaus would possess lower phylogenetic diversity. We found 55 bee species distributed along the nine sampling sites (plateaus) with 17 of them being singletons. There was a significant decrease in species richness with decreasing size of plateaus, and a significant decrease in the similarity in species composition with greater distance and climatic variation among sampling sites. Phylogenetic diversity varied among the sampling sites but was directly related to species richness. Although not significantly related to plateau area, smaller or larger PDFaith were observed in the smallest and the largest plateaus, respectively.

  20. Mortality from contact-related epidemics among indigenous populations in Greater Amazonia

    PubMed Central

    Walker, Robert S.; Sattenspiel, Lisa; Hill, Kim R.

    2015-01-01

    European expansion and contact with indigenous populations led to catastrophic depopulation primarily through the introduction of novel infectious diseases to which native peoples had limited exposure and immunity. In the Amazon Basin such contacts continue to occur with more than 50 isolated indigenous societies likely to make further contacts with the outside world in the near future. Ethnohistorical accounts are useful for quantifying trends in the severity and frequency of epidemics through time and may provide insight into the likely demographic consequences of future contacts. Here we compile information for 117 epidemics that affected 59 different indigenous societies in Greater Amazonia and caused over 11,000 deaths between 1875 and 2008, mostly (75%) from measles, influenza, and malaria. Results show that mortality rates from epidemics decline exponentially through time and, independently, with time since peaceful contact. The frequency of documented epidemics also decreases with time since contact. While previous work on virgin soil epidemics generally emphasizes the calamity of contacts, we focus instead on improvements through time. The prospects for better survivorship during future contacts are good provided modern health care procedures are implemented immediately. PMID:26354026

  1. Late Miocene sedimentary environments in south-western Amazonia (Solimões Formation; Brazil)

    PubMed Central

    Gross, Martin; Piller, Werner E.; Ramos, Maria Ines; Douglas da Silva Paz, Jackson

    2011-01-01

    In Miocene times a vast wetland existed in Western Amazonia. Whereas the general development of this amazing ecosystem is well established, many questions remain open on sedimentary environments, stratigraphical correlations as well as its palaeogeographical configuration. Several outcrops located in a barely studied region around Eirunepé (SW Amazonas state, Brazil) were investigated to obtain basic sedimentological data. The observed deposits belong to the upper part of the Solimões Formation and are biostratigraphically dated to the Late Miocene. Vertically as well as laterally highly variable fine-grained clastic successions were recorded. Based on the lithofacies assemblages, these sediments represent fluvial deposits, possibly of an anastomosing river system. Sand bodies formed within active channels and dominant overbank fines are described (levees, crevasse splays/channels/deltas, abandoned channels, backswamps, floodplain paleosols). Lacustrine environments are restricted to local floodplain ponds/lakes. The mollusc and ostracod content as well as very light δ18O and δ13C values, measured on ostracod valves, refer to exclusively freshwater conditions. Based on palaeontological and geological results the existence of a long-lived lake (“Lake Pebas”) or any influx of marine waters can be excluded for that region during the Late Miocene. PMID:26523089

  2. Regional-scale drivers of forest structure and function in northwestern Amazonia.

    PubMed

    Higgins, Mark A; Asner, Gregory P; Anderson, Christopher B; Martin, Roberta E; Knapp, David E; Tupayachi, Raul; Perez, Eneas; Elespuru, Nydia; Alonso, Alfonso

    2015-01-01

    Field studies in Amazonia have found a relationship at continental scales between soil fertility and broad trends in forest structure and function. Little is known at regional scales, however, about how discrete patterns in forest structure or functional attributes map onto underlying edaphic or geological patterns. We collected airborne LiDAR (Light Detection and Ranging) data and VSWIR (Visible to Shortwave Infrared) imaging spectroscopy measurements over 600 km2 of northwestern Amazonian lowland forests. We also established 83 inventories of plant species composition and soil properties, distributed between two widespread geological formations. Using these data, we mapped forest structure and canopy reflectance, and compared them to patterns in plant species composition, soils, and underlying geology. We found that variations in soils and species composition explained up to 70% of variation in canopy height, and corresponded to profound changes in forest vertical profiles. We further found that soils and plant species composition explained more than 90% of the variation in canopy reflectance as measured by imaging spectroscopy, indicating edaphic and compositional control of canopy chemical properties. We last found that soils explained between 30% and 70% of the variation in gap frequency in these forests, depending on the height threshold used to define gaps. Our findings indicate that a relatively small number of edaphic and compositional variables, corresponding to underlying geology, may be responsible for variations in canopy structure and chemistry over large expanses of Amazonian forest.

  3. Diversity of bats trypanosomes in hydroeletric area of Belo Monte in Brazilian Amazonia.

    PubMed

    da Costa, Andréa P; Nunes, Pablo Henrique; Leite, Beatriz Helena Santos; Ferreira, Juliana Isabel G da S; Tonhosolo, Renata; da Rosa, Adriana Ruckert; da Rocha, Patricio Adriano; Aires, Caroline Cotrim; Gennari, Solange Maria; Marcili, Arlei

    2016-12-01

    The Trypanosoma comprises flagellates able to infect many mammalian species and is transmitted by several groups of invertebrates. The order Chiroptera can be infected by the subgenera Herpetosoma, Schizotrypanum, Megatrypanum and Trypanozoon. In this study, we described the diversity of bats trypanosomes, inferring the phylogenetic relationships among the trypanosomes from bats caught Belo Monte Hydroeletric area (Brazilian Amazonia). Trypanosomes from bats were isolated by haemoculture, and the molecular phylogeny based on small subunit rDNA (SSU rDNA) and glycosomal-3-phosphate dehydrogenase (gGAPDH) gene sequences. Morphological characterization included light and scanning electron microscopy. A total of 157 bats were caught in the area belonging 6 Families (Emballonuridae, Furipteridae, Mormoopidae, Natalidae, Phyllostomidae and Vespertilionidae) and 34 species. The bat trypanosome prevalence, as evaluated through haemoculture, was 5,7%. Phylogenetic trees grouped the isolates in T. cruzi branch (TCI and TCbat lineage), T. cruzi marinkellei and Trypanosoma wauwau from Pteronotus parnellii. This is the first isolate from T. wauwau in Para state. The occurrence of T. cruzi in the ​​ Belo Monte Hydroeletric area (UHE Belo Monte) in Amazon/Brazil attentive to the risk of migration human population required for the works of the dam and new cities that grow in the vicinity of these businesses, but it is a zoonosis already known to the Amazon region, and the presence of unclassified Trypanosoma species, attend to the large parasitic biodiversity still unknown.

  4. Tersilochinae of Western Amazonia (Hymenoptera: Ichneumonidae). Genus Stethantyx Townes, part 2.

    PubMed

    Khalaim, Andrey I; Sääksjärvi, Ilari E; Bordera, Santiago

    2015-07-02

    In this paper we describe four new species of Stethantyx Townes (Ichneumonidae: Tersilochinae) from Ecuador and Peru characterized by the fore wing with first and second abscissae of radius meeting at right angle: S. erwini Khalaim & Sääksjärvi, sp. nov., S. radiata Khalaim & Sääksjärvi, sp. nov., S. rufispa Khalaim & Bordera, sp. nov. and S. undulata Khalaim & Sääksjärvi, sp. nov. Second part of the key to species of Stethantyx occurring in Western Amazonia is given. Additionally, S. altamira Khalaim & Broad and S. aprica Khalaim & Broad are recorded from South America for the first time, and new data on distribution of S. alajuela Khalaim & Broad, S. amazonica Khalaim & Sääksjärvi, S. heredia Kha-laim & Broad, S. orellana Khalaim & Sääksjärvi, S. sinuata Khalaim & Sääksjärvi and S. trepida Khalaim & Sääksjärvi in South America are provided. Male of S. orellana is recorded for the first time.

  5. Responses of Aquatic Saproxylic Macroinvertebrates to Reduced-Impact Logging in Central Amazonia.

    PubMed

    Roque, F O; Escarpinati, S C; Valente-Neto, F; Hamada, N

    2015-08-01

    Reduced-impact logging (RIL) is an alternative land use because it reduces damage to forest cover in comparison with clear-cut practices. However, management practices adopted in RIL can affect wood availability and, consequently, fauna associated with dead wood during part of their life cycle (saproxylic). In this study, we evaluated whether aquatic saproxylic macroinvertebrates are affected by reduced-impact logging in Central Amazonia. We selected six streams in areas under reduced-impacted logging and six in primary forest areas and collected submerged woody debris. We did not find any differences in water pH, conductivity, and wood availability between reduced-impacted forest and primary forest streams. We found 248 saproxylic aquatic macroinvertebrates belonging to 37 taxa. We found five wood specialist (Dryops, Lutrochus, Stenochironomus, Oukuriella, and Endotribelos) and 32 generalists, totalling 98 and 150 individuals, respectively. In general, our results show that reduced-impact logging does not affect richness, abundance, and composition of saproxylic macroinvertebrates. The main explanation for this pattern is that management practices do not change important macroinvertebrate niche dimensions, including wood availability and the water's chemical and physical variables. Thus, controlled logging, such as applied in the area of the Central Amazonian streams studied, opens a new prospect for insect conservation and commercial exploitation of wood, which is not possible when clear-cut practices are adopted.

  6. Environmental Costs of Government-Sponsored Agrarian Settlements in Brazilian Amazonia.

    PubMed

    Schneider, Maurício; Peres, Carlos A

    2015-01-01

    Brazil has presided over the most comprehensive agrarian reform frontier colonization program on Earth, in which ~1.2 million settlers have been translocated by successive governments since the 1970's, mostly into forested hinterlands of Brazilian Amazonia. These settlements encompass 5.3% of this ~5 million km2 region, but have contributed with 13.5% of all land conversion into agropastoral land uses. The Brazilian Federal Agrarian Agency (INCRA) has repeatedly claimed that deforestation in these areas largely predates the sanctioned arrival of new settlers. Here, we quantify rates of natural vegetation conversion across 1911 agrarian settlements allocated to 568 Amazonian counties and compare fire incidence and deforestation rates before and after the official occupation of settlements by migrant farmers. The timing and spatial distribution of deforestation and fires in our analysis provides irrefutable chronological and spatially explicit evidence of agropastoral conversion both inside and immediately outside agrarian settlements over the last decade. Deforestation rates are strongly related to local human population density and road access to regional markets. Agrarian settlements consistently accelerated rates of deforestation and fires, compared to neighboring areas outside settlements, but within the same counties. Relocated smallholders allocated to forest areas undoubtedly operate as pivotal agents of deforestation, and most of the forest clearance occurs in the aftermath of government-induced migration.

  7. Late Miocene sedimentary environments in south-western Amazonia (Solimões Formation; Brazil).

    PubMed

    Gross, Martin; Piller, Werner E; Ramos, Maria Ines; Douglas da Silva Paz, Jackson

    2011-08-01

    In Miocene times a vast wetland existed in Western Amazonia. Whereas the general development of this amazing ecosystem is well established, many questions remain open on sedimentary environments, stratigraphical correlations as well as its palaeogeographical configuration. Several outcrops located in a barely studied region around Eirunepé (SW Amazonas state, Brazil) were investigated to obtain basic sedimentological data. The observed deposits belong to the upper part of the Solimões Formation and are biostratigraphically dated to the Late Miocene. Vertically as well as laterally highly variable fine-grained clastic successions were recorded. Based on the lithofacies assemblages, these sediments represent fluvial deposits, possibly of an anastomosing river system. Sand bodies formed within active channels and dominant overbank fines are described (levees, crevasse splays/channels/deltas, abandoned channels, backswamps, floodplain paleosols). Lacustrine environments are restricted to local floodplain ponds/lakes. The mollusc and ostracod content as well as very light δ(18)O and δ(13)C values, measured on ostracod valves, refer to exclusively freshwater conditions. Based on palaeontological and geological results the existence of a long-lived lake ("Lake Pebas") or any influx of marine waters can be excluded for that region during the Late Miocene.

  8. Mortality from contact-related epidemics among indigenous populations in Greater Amazonia.

    PubMed

    Walker, Robert S; Sattenspiel, Lisa; Hill, Kim R

    2015-09-10

    European expansion and contact with indigenous populations led to catastrophic depopulation primarily through the introduction of novel infectious diseases to which native peoples had limited exposure and immunity. In the Amazon Basin such contacts continue to occur with more than 50 isolated indigenous societies likely to make further contacts with the outside world in the near future. Ethnohistorical accounts are useful for quantifying trends in the severity and frequency of epidemics through time and may provide insight into the likely demographic consequences of future contacts. Here we compile information for 117 epidemics that affected 59 different indigenous societies in Greater Amazonia and caused over 11,000 deaths between 1875 and 2008, mostly (75%) from measles, influenza, and malaria. Results show that mortality rates from epidemics decline exponentially through time and, independently, with time since peaceful contact. The frequency of documented epidemics also decreases with time since contact. While previous work on virgin soil epidemics generally emphasizes the calamity of contacts, we focus instead on improvements through time. The prospects for better survivorship during future contacts are good provided modern health care procedures are implemented immediately.

  9. The legacy of the Pleistocene megafauna extinctions on nutrient availability in Amazonia

    NASA Astrophysics Data System (ADS)

    Doughty, Christopher E.; Wolf, Adam; Malhi, Yadvinder

    2013-09-01

    In the late Pleistocene, 97 genera of large animals went extinct, concentrated in the Americas and Australia. These extinctions had significant effects on ecosystem structure, seed dispersal and land surface albedo. However, the impact of this dramatic extinction on ecosystem nutrient biogeochemistry, through the lateral transport of dung and bodies, has never been explored. Here we analyse this process using a novel mathematical framework that analyses this lateral transport as a diffusion-like process, and we demonstrate that large animals play a disproportionately large role in the horizontal transfer of nutrients across landscapes. For example, we estimate that the extinction of the Amazonian megafauna decreased the lateral flux of the limiting nutrient phosphorus by more than 98%, with similar, though less extreme, decreases in all continents outside of Africa. This resulted in strong decreases in phosphorus availability in eastern Amazonia away from fertile floodplains, a decline which may still be ongoing. The current P limitation in the Amazon basin may be partially a relic of an ecosystem without the functional connectivity it once had. We argue that the Pleistocene megafauna extinctions resulted in large and ongoing disruptions to terrestrial biogeochemical cycling at continental scales and increased nutrient heterogeneity globally.

  10. Population Development of Zabrotes subfasciatus (Coleoptera: Chrysomelidae) in Landrace Bean Varieties Occurring in Southwestern Amazonia.

    PubMed

    Lopes, L M; Araújo, A E F; Santos, A C V; Santos, V B; Sousa, A H

    2016-02-01

    The common bean, Phaseolus vulgaris (L.), is one of the most important sources of protein worldwide, and Latin America is one of the recognized centers of diversity of this species. However, storage of this product after harvest is not feasible because of bruchid attacks. This study determined the accumulated normalized rate of emergence and the daily emergence rate of Zabrotes subfasciatus (Boheman) (Coleoptera: Chrysomelidae:Bruchinae) in five landrace varieties of common bean (BRL 01, SNA 01, RDR 01, RBC 01, and RBC 13) that occurin southwestern Amazonia. These varieties were selected for this study because they are well-distributed throughout the Amazonian communities. Beans of each variety were infested with 50 unsexed adults, and the insects were removed 13 d after beginning the bioassays. The adult progeny obtained from the feeding substrate were counted and removed every other day after the first emergence, until the end of the emergence period. Differences were observed in the calculated rates of development; however, the time required for development and emergence of the insects was independent. Of the five varieties of bean investigated, we observed that the RDR 01, BRL 01, and SNA 01 cultivars are resistant to Z. subfasciatus; the results indicate that the use of these three varieties can reduce problems associated with bruchid attacks and enable storage of the product after harvesting.

  11. Late Pleistocene-Holocene paleoclimate in southwestern Brazilian Amazonia with basis on floristic changes interpreted from isotope data

    NASA Astrophysics Data System (ADS)

    Rossetti, D. F.; Cohen, M. C. L.; Pessenda, L. C. R.

    2015-12-01

    Previous late Quaternary paleoclimatic interpretations in Amazonia have considered fluctuating dry to wet episodes with changes from savanna to forest, a view that concurs with other proposals of undisturbed rainforest despite global oscillations. Most of this debate is based on pollen data, but such elements are scarce in Amazonian sedimentary records. This work interprets vegetation in the Late Pleistocene and Holocene in a southwestern Amazonia lowland using δ13C, δ15N, C/N integrated with geomorphology, sedimentology and radiocarbon dating. The goal was to reconstruct vegetation changes through time and analyze their relation to climate and sedimentary dynamics. Fluvial channel and floodplain deposits with phytoplankton, as well as C3 and C4 land plants, were recorded. Between 42,033-43,168 cal yr BP and 34,804-35,584 cal yr BP, C4 land plants increased as a result of a climate drier than todaýs. However, wet climate prevailed from this time-frame until the onset of the Last Glaciation Maximum. In the Pleistocene/Holocene transition, there was an increased contribution of C4 land plants potentially related to dry episodes. However, the increased contribution of this type of land plant is not synchronous with Holocene dry episodes previously documented for the Amazonian lowland. On the other hand, it is remarkable that the record of this plant type was verified only in sites with modern grassland confined to fluvial paleo-landforms. Thus, rather than due to a dry climatic episode, the recorded grassland expansion and its maintenance up to the present time in the studied sites is more likely associated with the evolution of depositional environments, being coincidental with the progressive abandonment of fluvial systems. An important conclusion derived from the present work is that great care must be placed when reconstructing late Quaternary paleoclimate in Amazonia based on changes in floristic patterns, as they may be also a response to sedimentary dynamics.

  12. On the ability of a global atmospheric inversion to constrain variations of CO2 fluxes over Amazonia

    NASA Astrophysics Data System (ADS)

    Molina, L.; Broquet, G.; Imbach, P.; Chevallier, F.; Poulter, B.; Bonal, D.; Burban, B.; Ramonet, M.; Gatti, L. V.; Wofsy, S. C.; Munger, J. W.; Dlugokencky, E.; Ciais, P.

    2015-01-01

    The exchanges of carbon, water, and energy between the atmosphere and the Amazon Basin have global implications for current and future climate. Here, the global atmospheric inversion system of the Monitoring of Atmospheric Composition and Climate service (MACC) was used to further study the seasonal and interannual variations of biogenic CO2 fluxes in Amazonia. The system assimilated surface measurements of atmospheric CO2 mole fractions made over more than 100 sites over the globe into an atmospheric transport model. This study added four surface stations located in tropical South America, a region poorly covered by CO2 observations. The estimates of net ecosystem exchange (NEE) optimized by the inversion were compared to independent estimates of NEE upscaled from eddy-covariance flux measurements in Amazonia, and against reports on the seasonal and interannual variations of the land sink in South America from the scientific literature. We focused on the impact of the interannual variation of the strong droughts in 2005 and 2010 (due to severe and longer-than-usual dry seasons), and of the extreme rainfall conditions registered in 2009. The spatial variations of the seasonal and interannual variability of optimized NEE were also investigated. While the inversion supported the assumption of strong spatial heterogeneity of these variations, the results revealed critical limitations that prevent global inversion frameworks from capturing the data-driven seasonal patterns of fluxes across Amazonia. In particular, it highlighted issues due to the configuration of the observation network in South America and the lack of continuity of the measurements. However, some robust patterns from the inversion seemed consistent with the abnormal moisture conditions in 2009.

  13. On the ability of a global atmospheric inversion to constrain variations of CO2 fluxes over Amazonia

    NASA Astrophysics Data System (ADS)

    Molina, L.; Broquet, G.; Imbach, P.; Chevallier, F.; Poulter, B.; Bonal, D.; Burban, B.; Ramonet, M.; Gatti, L. V.; Wofsy, S. C.; Munger, J. W.; Dlugokencky, E.; Ciais, P.

    2015-07-01

    The exchanges of carbon, water and energy between the atmosphere and the Amazon basin have global implications for the current and future climate. Here, the global atmospheric inversion system of the Monitoring of Atmospheric Composition and Climate (MACC) service is used to study the seasonal and interannual variations of biogenic CO2 fluxes in Amazonia during the period 2002-2010. The system assimilated surface measurements of atmospheric CO2 mole fractions made at more than 100 sites over the globe into an atmospheric transport model. The present study adds measurements from four surface stations located in tropical South America, a region poorly covered by CO2 observations. The estimates of net ecosystem exchange (NEE) optimized by the inversion are compared to an independent estimate of NEE upscaled from eddy-covariance flux measurements in Amazonia. They are also qualitatively evaluated against reports on the seasonal and interannual variations of the land sink in South America from the scientific literature. We attempt at assessing the impact on NEE of the strong droughts in 2005 and 2010 (due to severe and longer-than-usual dry seasons) and the extreme rainfall conditions registered in 2009. The spatial variations of the seasonal and interannual variability of optimized NEE are also investigated. While the inversion supports the assumption of strong spatial heterogeneity of these variations, the results reveal critical limitations of the coarse-resolution transport model, the surface observation network in South America during the recent years and the present knowledge of modelling uncertainties in South America that prevent our inversion from capturing the seasonal patterns of fluxes across Amazonia. However, some patterns from the inversion seem consistent with the anomaly of moisture conditions in 2009.

  14. Disentangling the contribution of multiple land covers to fire-mediated carbon emissions in Amazonia during the 2010 drought.

    PubMed

    Anderson, Liana Oighenstein; Aragão, Luiz E O C; Gloor, Manuel; Arai, Egídio; Adami, Marcos; Saatchi, Sassan S; Malhi, Yadvinder; Shimabukuro, Yosio E; Barlow, Jos; Berenguer, Erika; Duarte, Valdete

    2015-10-01

    In less than 15 years, the Amazon region experienced three major droughts. Links between droughts and fires have been demonstrated for the 1997/1998, 2005, and 2010 droughts. In 2010, emissions of 510 ± 120 Tg C were associated to fire alone in Amazonia. Existing approaches have, however, not yet disentangled the proportional contribution of multiple land cover sources to this total. We develop a novel integration of multisensor and multitemporal satellite-derived data on land cover, active fires, and burned area and an empirical model of fire-induced biomass loss to quantify the extent of burned areas and resulting biomass loss for multiple land covers in Mato Grosso (MT) state, southern Amazonia-the 2010 drought most impacted region. We show that 10.77% (96,855 km(2)) of MT burned. We estimated a gross carbon emission of 56.21 ± 22.5 Tg C from direct combustion of biomass, with an additional 29.4 ± 10 Tg C committed to be emitted in the following years due to dead wood decay. It is estimated that old-growth forest fires in the whole Brazilian Legal Amazon (BLA) have contributed to 14.81 Tg of C (11.75 Tg C to 17.87 Tg C) emissions to the atmosphere during the 2010 fire season, with an affected area of 27,555 km(2). Total C loss from the 2010 fires in MT state and old-growth forest fires in the BLA represent, respectively, 77% (47% to 107%) and 86% (68.2% to 103%) of Brazil's National Plan on Climate Change annual target for Amazonia C emission reductions from deforestation.

  15. Ecological Adaptation of Wild Peach Palm, Its In Situ Conservation and Deforestation-Mediated Extinction in Southern Brazilian Amazonia

    PubMed Central

    Clement, Charles R.; Santos, Ronaldo P.; Desmouliere, Sylvain J. M.; Ferreira, Evandro J. L.; Neto, João Tomé Farias

    2009-01-01

    Background The Arc of Fire across southern Amazonia seasonally attracts worldwide attention as forests are cut and burned for agricultural expansion. These forests contain numerous wild relatives of native South American crops, such as peach palm. Methodology/Principal Findings Our prospecting expeditions examined critical areas for wild peach palm in the Arc of Fire in Mato Grosso, Pará, Maranhão and Tocantins, as well as areas not previously examined in Amazonas and Amapá states. Recent digitization of the RADAM Brasil project permitted comparison among RADAM's parataxonomists' observations, previous botanical collections and our prospecting. Mapping on soils and vegetation types enabled us to hypothesize a set of ecological preferences. Wild peach palm is best adapted to Ultisols (Acrisols) in open forests across the Arc of Fire and westward into the more humid western Amazonia. Populations are generally small (fewer than 10 plants) on slopes above watercourses. In northern Mato Grosso and southern Pará soybean fields and pastures now occupy numerous areas where RADAM identified wild peach palm. The controversial BR-163 Highway is already eroding wild peach palm as deforestation expands. Conclusions/Significance Many of these populations are now isolated by increasing forest fragmentation, which will lead to decreased reproduction via inbreeding depression and eventual extinction even without complete deforestation. Federal conservation areas are less numerous in the Arc of Fire than in other parts of Brazilian Amazonia, although there are indigenous lands; these conservation areas contain viable populations of wild peach palm and require better protection than they are currently receiving. Ex situ conservation of these populations is not viable given the relative lack of importance of domesticated peach palm and the difficulty of maintaining even economically interesting genetic resources. PMID:19238213

  16. Morphological characterization of Eustrongylides sp. larvae (Nematoda, Dioctophymatoidea) parasite of Rhinella marina (Amphibia: Bufonidae) from Eastern Amazonia.

    PubMed

    Melo, Francisco Tiago de Vasconcelos; Melo, Caroline do Socorro Barros; Nascimento, Luciana de Cássia Silva do; Giese, Elane Guerreiro; Furtado, Adriano Penha; Santos, Jeannie Nascimento Dos

    2016-06-07

    Absctract Eustrongylides spp. nematodes have birds as final hosts and uses other vertebrates as intermediate/paratenic host (fish, amphibians and reptiles) and have zoonotic potential. In amphibians, the larvae may be located in the subcutaneous tissues, liver and mesentery, between the muscle fibres, especially in the lower limbs. Rhinella marina, which is widely observed in Brazil, has exhibited complex diversity in its helminth fauna, reflecting the unique habitat of the Amazon biome. For the first time, this study describes the morphological aspects of third-stage larvae of Eustrongylides sp. in Rhinella marina from Santa Cruz do Ararí, Marajó Archipelago, Eastern Amazonia, using light and scanning electron microscopy.

  17. Geographic distribution and abundance of woolly (Lagothrix cana) and spider (Ateles chamek) monkeys in southwestern Brazilian Amazonia.

    PubMed

    Iwanaga, Simone; Ferrari, Stephen F

    2002-01-01

    Two species of frugivorous atelids, Ateles chamek and Lagothrix cana, occur in southwestern Brazilian Amazonia. Populations were surveyed at 36 sites in the state of Rondônia. Ateles chamek is widespread, but the distribution of L. cana is limited by a combination of riverine barriers and ecological factors, possibly including competition with A. chamek. Groups of L. cana were generally larger and more abundant than those of A. chamek, even in syntopy. The transitional forest that predominates in the extreme south of Rondônia (Hylea-cerrado) is not a barrier to either species, with both species being tolerant of habitat disturbance when hunting pressure is low.

  18. a Bayesian Approach for Calibration of Trmm 3B42 Over North Amazonia

    NASA Astrophysics Data System (ADS)

    Linguet, L.; Marie-Joseph, I.; Becker, M.; Seyler, F.

    2013-12-01

    Northern Amazonian regions experience extremes conditions like floods and droughts. These regions are also characterized by the limited spatial coverage of ground based rain gauges, and unavailability of real-time rainfall data. Satellite-based rainfall estimates (SRE) may be one of the best and appropriate approaches in detecting rainfall distribution. However SRE data need specific calibration and validation for use in flood and drought monitoring activities. This study aimed to calibrate of TRMM 3B42 RT rainfall products over northern Amazonia with a Bayesian filtering approach [1] [2]. The study area is located north of the Amazon River and includes the three Guianas and northern states of Brazil. A set of daily satellite rainfall products with spatial resolution of 0.25°x0.25° (TRMM 3B42 RT) from the year 2000 to 2010 has been selected. Ground reference data are located in French Guiana (27 ground stations from French national meteorological agency) and in the northern Brazilian states (70 ground stations from Brazilian Agência Nacional de Aguas). A lot of bias-adjustment methods rely on computing the difference between satellite and gauge-based precipitation [3] [4]. In this study we defend the idea that an inverse approach based on sequential Monte Carlo filtering helps to calibrate of TRMM 3B42 RT rainfall products. The developed method combines a model of the rainfall process at rain gauge locations with a stochastic observation model based on the joint distribution between ground reference data of the state variable (rainfall data) and the observed satellite data. 50% of the total ground based rainfall measurements were used for the joint distribution and the remaining 50% were used for validation purposes. Validation of the method has been done by comparing the corrected satellite data against independent observed data from rain gauges using the standard verification techniques: mean bias error, root mean square error, and correlation coefficient

  19. Impacts of Amazonia biomass burning aerosols assessed from short-range weather forecasts

    NASA Astrophysics Data System (ADS)

    Kolusu, S. R.; Marsham, J. H.; Mulcahy, J.; Johnson, B.; Dunning, C.; Bush, M.; Spracklen, D. V.

    2015-07-01

    The direct radiative impacts of Biomass Burning Aerosols (BBA) on meteorology are investigated using short-range forecasts from the Met Office Unified Model (MetUM) over South America during the South American Biomass Burning Analysis (SAMBBA). The impacts are evaluated using a set of three simulations: (i) no aerosols, (ii) with monthly mean aerosol climatologies and (iii) with prognostic aerosols modelled using the Coupled Large-scale Aerosol Simulator for Studies in Climate (CLASSIC) scheme. Comparison with observations show that the prognostic CLASSIC scheme provides the best representation of BBA. The impacts of BBA are quantified over central and southern Amazonia from the first and second day of two day forecasts during 14 September-03 October 2012. On average, during the first day of the forecast, including prognostic BBA reduces the clear-sky net radiation at the surface by 15 ± 1 W m-2, and reduces net TOA radiation by 8 ± 1 W m-2, with a direct atmospheric warming of 7 ± 1 W m-2. BBA-induced reductions in all-sky radiation are smaller in magnitude: 9.0 ± 1 W m-2 at the surface and 4.0 ± 1 W m-2 at TOA. In this modelling study the BBA therefore exert an overall cooling influence on the Earth-atmosphere system, although some levels of the atmosphere are directly warmed by the absorption of solar radiation. Due to the reduction of net radiative flux at the surface the mean 2 m air temperature is reduced by around 0.1 ± 0.02 °C. The BBA also cools the boundary layer (BL) but warms air above by around 0.2 °C due to the absorption of shortwave radiation. The overall impact is to reduce the BL depth by around 19 ± 8 m. These differences in heating lead to a more anticyclonic circulation at 700 hPa, with winds changing by around 0.6 m s-1. Inclusion of BBA in the MetUM significantly improves forecasts of temperature and relative humidity, but effects were small compared with model error and differences between effects from climatological and prognostic

  20. Impacts of Amazonia biomass burning aerosols assessed from short-range weather forecasts

    NASA Astrophysics Data System (ADS)

    Kolusu, S. R.; Marsham, J. H.; Mulcahy, J.; Johnson, B.; Dunning, C.; Bush, M.; Spracklen, D. V.

    2015-11-01

    The direct radiative impacts of biomass burning aerosols (BBA) on meteorology are investigated using short-range forecasts from the Met Office Unified Model (MetUM) over South America during the South American Biomass Burning Analysis (SAMBBA). The impacts are evaluated using a set of three simulations: (i) no aerosols, (ii) with monthly mean aerosol climatologies and (iii) with prognostic aerosols modelled using the Coupled Large-scale Aerosol Simulator for Studies In Climate (CLASSIC) scheme. Comparison with observations show that the prognostic CLASSIC scheme provides the best representation of BBA. The impacts of BBA are quantified over central and southern Amazonia from the first and second day of 2-day forecasts during 14 September-3 October 2012. On average, during the first day of the forecast, including prognostic BBA reduces the clear-sky net radiation at the surface by 15 ± 1 W m-2 and reduces net top-of-atmosphere (TOA) radiation by 8 ± 1 W m-2, with a direct atmospheric warming of 7 ± 1 W m-2. BBA-induced reductions in all-sky radiation are smaller in magnitude: 9.0 ± 1 W m-2 at the surface and 4.0 ± 1 W m-2 at TOA. In this modelling study the BBA therefore exert an overall cooling influence on the Earth-atmosphere system, although some levels of the atmosphere are directly warmed by the absorption of solar radiation. Due to the reduction of net radiative flux at the surface, the mean 2 m air temperature is reduced by around 0.1 ± 0.02 °C. The BBA also cools the boundary layer (BL) but warms air above by around 0.2 °C due to the absorption of shortwave radiation. The overall impact is to reduce the BL depth by around 19 ± 8 m. These differences in heating lead to a more anticyclonic circulation at 700 hPa, with winds changing by around 0.6 m s-1. Inclusion of climatological or prognostic BBA in the MetUM makes a small but significant improvement in forecasts of temperature and relative humidity, but improvements were small compare with model

  1. Synergistic impacts of deforestation, climate change and fire on the future biomes distribution in Amazonia

    NASA Astrophysics Data System (ADS)

    Sampaio, G.; Cardoso, M. F.; Nobre, C. A.; Salazar, L. F.

    2013-05-01

    Several studies indicate future increase of environmental risks for the ecosystems in the Amazon region as a result of climate and land-use change, and their synergistic interactions. Modeling studies (e.g. Oyama and Nobre 2004, Salazar et al. 2007, Malhi et al. 2008) project rapid and irreversible replacement of forests by savannas with large-scale losses of biodiversity and livelihoods for people in the region. This process is referred to as the Amazon Dieback, where accelerated plant mortality due to environmental changes lead to forest collapse and savannas expansion after "tipping points" in climate and land surface changes are achieved. In this study we performed new analyses to quantify how deforestation, climate change and fire may combine to affect the distribution of major biomes in Amazonia. Changes in land use consider deforestation scenarios of 0%, 20%, 40%, and 50% (Sampaio et al., 2007), with and without fires (Cardoso et al., 2008), under the two greenhouse gases scenarios B1 and A2 and three "representative concentration pathways" (RCPs): 2.6, 4.5 and 8.5, for years 2015-2034 and 2040-2059 ("2025" and "2050" time-slices), from IPCC AR4 and CMIP5. The results show that the area affected in scenarios A2 and RCP 8.5 is larger than in the climate scenario B1 and RCP 2.6, and in both cases the effect is progressively higher in time. Most important changes occur in the East and South of the Amazon, with replacement of tropical forest by seasonal forest and savanna. The effect of fire in this region is important in all scenarios. The Northwest Amazon presents the smallest changes in the area of tropical forest, indicating that even for substantial land-use modifications and global climate change, the resulting atmospheric conditions would still support tropical forest in the region. In summary, we conclude that the synergistic combination of deforestation, climate change resulting from global warming, and the potential for higher fire occurrence may lead

  2. Molecular composition of organic aerosols in central Amazonia: an ultra-high-resolution mass spectrometry study

    NASA Astrophysics Data System (ADS)

    Kourtchev, Ivan; Godoi, Ricardo H. M.; Connors, Sarah; Levine, James G.; Archibald, Alex T.; Godoi, Ana F. L.; Paralovo, Sarah L.; Barbosa, Cybelli G. G.; Souza, Rodrigo A. F.; Manzi, Antonio O.; Seco, Roger; Sjostedt, Steve; Park, Jeong-Hoo; Guenther, Alex; Kim, Saewung; Smith, James; Martin, Scot T.; Kalberer, Markus

    2016-09-01

    The Amazon Basin plays key role in atmospheric chemistry, biodiversity and climate change. In this study we applied nanoelectrospray (nanoESI) ultra-high-resolution mass spectrometry (UHRMS) 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, carbon oxidation state and aromaticity equivalent) were used to identify compound classes and mass distributions of the detected species. Nitrogen- and/or sulfur-containing organic species contributed up to 60 % of the total identified number of formulae. A large number of molecular formulae in organic aerosol (OA) were attributed to later-generation nitrogen- and sulfur-containing oxidation products, suggesting that OA composition is affected by biomass burning and other, potentially anthropogenic, sources. Isoprene-derived organosulfate (IEPOX-OS) was found to be the most dominant ion in most of the analysed samples and strongly followed the concentration trends of the gas-phase anthropogenic tracers confirming its mixed anthropogenic-biogenic origin. The presence of oxidised aromatic and nitro-aromatic compounds in the samples suggested a strong influence from biomass burning especially during the dry period. Aerosol samples from the dry period and under enhanced biomass burning conditions contained a large number of molecules with high carbon oxidation state and an increased number of aromatic compounds compared to that from the wet period. The results of this work demonstrate that the studied site is influenced not only by biogenic emissions from the forest but also by biomass burning and potentially other anthropogenic emissions from the neighbouring urban environments.

  3. The Challenges from Extreme Climate Events for Sustainable Development in Amazonia: the Acre State Experience

    NASA Astrophysics Data System (ADS)

    Araújo, M. D. N. M.

    2015-12-01

    In the past ten years Acre State, located in Brazil´s southwestern Amazonia, has confronted sequential and severe extreme events in the form of droughts and floods. In particular, the droughts and forest fires of 2005 and 2010, the 2012 flood within Acre, the 2014 flood of the Madeira River which isolated Acre for two months from southern Brazil, and the most severe flooding throughout the state in 2015 shook the resilience of Acrean society. The accumulated costs of these events since 2005 have exceeded 300 million dollars. For the last 17 years, successive state administrations have been implementing a socio-environmental model of development that strives to link sustainable economic production with environmental conservation, particularly for small communities. In this context, extreme climate events have interfered significantly with this model, increasing the risks of failure. The impacts caused by these events on development in the state have been exacerbated by: a) limitations in monitoring; b) extreme events outside of Acre territory (Madeira River Flood) affecting transportation systems; c) absence of reliable information for decision-making; and d) bureaucratic and judicial impediments. Our experience in these events have led to the following needs for scientific input to reduce the risk of disasters: 1) better monitoring and forecasting of deforestation, fires, and hydro-meteorological variables; 2) ways to increase risk perception in communities; 3) approaches to involve more effectively local and regional populations in the response to disasters; 4) more accurate measurements of the economic and social damages caused by these disasters. We must improve adaptation to and mitigation of current and future extreme climate events and implement a robust civil defense, adequate to these new challenges.

  4. Ecological speciation in the tropics: insights from comparative genetic studies in Amazonia

    PubMed Central

    Beheregaray, Luciano B.; Cooke, Georgina M.; Chao, Ning L.; Landguth, Erin L.

    2015-01-01

    Evolution creates and sustains biodiversity via adaptive changes in ecologically relevant traits. Ecologically mediated selection contributes to genetic divergence both in the presence or absence of geographic isolation between populations, and is considered an important driver of speciation. Indeed, the genetics of ecological speciation is becoming increasingly studied across a variety of taxa and environments. In this paper we review the literature of ecological speciation in the tropics. We report on low research productivity in tropical ecosystems and discuss reasons accounting for the rarity of studies. We argue for research programs that simultaneously address biogeographical and taxonomic questions in the tropics, while effectively assessing relationships between reproductive isolation and ecological divergence. To contribute toward this goal, we propose a new framework for ecological speciation that integrates information from phylogenetics, phylogeography, population genomics, and simulations in evolutionary landscape genetics (ELG). We introduce components of the framework, describe ELG simulations (a largely unexplored approach in ecological speciation), and discuss design and experimental feasibility within the context of tropical research. We then use published genetic datasets from populations of five codistributed Amazonian fish species to assess the performance of the framework in studies of tropical speciation. We suggest that these approaches can assist in distinguishing the relative contribution of natural selection from biogeographic history in the origin of biodiversity, even in complex ecosystems such as Amazonia. We also discuss on how to assess ecological speciation using ELG simulations that include selection. These integrative frameworks have considerable potential to enhance conservation management in biodiversity rich ecosystems and to complement historical biogeographic and evolutionary studies of tropical biotas. PMID:25653668

  5. Tropical Timber Rush in Peruvian Amazonia: Spatial Allocation of Forest Concessions in an Uninventoried Frontier

    NASA Astrophysics Data System (ADS)

    Salo, Matti; Toivonen, Tuuli

    2009-10-01

    Land-use allocation has important implications for the conservation and management of tropical forests. Peru’s forestry regime has recently been reformed and more than 7 million ha has been assigned as forest concessions. This potentially has a drastic impact on the land-use practices and species composition of the assigned areas. Nevertheless, the environmental variation found within the concessions and the process applied to delimit them are poorly studied and documented. Thus, it is difficult to estimate the biological impacts of forestry activities in concessions or plan them sustainably. This paper reveals the characteristics of the current concession allocation in Loreto, Peruvian Amazonia, using environmental and access-related variables and compares the concessions to other major land-use assignments. The work draws on a number of data sets describing land-use, ecosystem diversity, and fluvial network in the region. According to our data, certain environment types such as relatively fertile Pebas soils are overrepresented in the concessions, while others, like floodplain forests, are underrepresented in comparison to other land-use assignments. Concessions also have less anthropogenic disturbance than other areas. Furthermore, concessions are located on average further from the river network than the other land-use assignments studied. We claim that forest classification based on productivity, soil fertility, accessibility, and biodiversity patterns is an achievable long-term goal for forest authorities in Peru, and in many other tropical countries. We present a rough design of a geographic information system incorporating environmental, logging, and access-related data that could be applied to approach this goal in Peru.

  6. The Temporal Scale of Holocene Climatic Variability: From the Galapagos to Amazonia

    NASA Astrophysics Data System (ADS)

    Bush, M. B.; Restrepo, A.; Correa, A.; Ford, R.; Valencia, B.; Gosling, W.; Silman, M.; Conroy, J.; Overpeck, J. T.

    2006-12-01

    High-resolution lake cores from the Andes and Amazonian lowlands of W. South America and the Galapagos Islands provide new insights into the Holocene climate history of this region and its interactions with Pacific climate drivers. Our data reveal that a major drought event reported broadly from the Andes and Amazonia in the early to mid-Holocene is actually a complex series of droughts with wet interludes. These results suggest strong climatic instability prior to c. 5600 cal. yr BP. Establishment of wetter conditions at our Andean study site at c. 5600 cal. yr BP correspond to the start of Quinoa cultivation. A similar pattern of higher lake levels coinciding with the local spread of agriculture is also evident in the lowlands. Within an overall pattern of progressively wetter conditions over the last 4000 years there are periods of pronounced climatic instability (drought and flood). Fossil pollen, charcoal, sediment color, and carbon content identify periods of peak erosion between c. 900 and 1100 cal. yr BP. On the Galapagos Islands, a subdecadally resolved analysis of fossil pollen provides a striking pattern of climatic change and human-induced alteration of the landscape. Prior to the period of transforming human activity, the fossil pollen record contains a multidecadal oscillation, with wavlet analysis evealing a quasi- periodicty of c. 60 years. Andean pollen are readily identifible in the Galapagos record and transport of mainland pollen to the islands has varied markedly within the past millennium. These multiproxy records reveal the dynamic nature of Holocene climates in the tropics and the impact those changes have had on people and landscapes.

  7. Increased Wildfire Risk Driven by Climate and Development Interactions in the Bolivian Chiquitania, Southern Amazonia

    PubMed Central

    Devisscher, Tahia; Anderson, Liana O.; Aragão, Luiz E. O. C.; Galván, Luis; Malhi, Yadvinder

    2016-01-01

    Wildfires are becoming increasingly dominant in tropical landscapes due to reinforcing feedbacks between land cover change and more severe dry conditions. This study focused on the Bolivian Chiquitania, a region located at the southern edge of Amazonia. The extensive, unique and well-conserved tropical dry forest in this region is susceptible to wildfires due to a marked seasonality. We used a novel approach to assess fire risk at the regional level driven by different development trajectories interacting with changing climatic conditions. Possible future risk scenarios were simulated using maximum entropy modelling with presence-only data, combining land cover, anthropogenic and climatic variables. We found that important determinants of fire risk in the region are distance to roads, recent deforestation and density of human settlements. Severely dry conditions alone increased the area of high fire risk by 69%, affecting all categories of land use and land cover. Interactions between extreme dry conditions and rapid frontier expansion further increased fire risk, resulting in potential biomass loss of 2.44±0.8 Tg in high risk area, about 1.8 times higher than the estimates for the 2010 drought. These interactions showed particularly high fire risk in land used for ‘extensive cattle ranching’, ‘agro-silvopastoral use’ and ‘intensive cattle ranching and agriculture’. These findings have serious implications for subsistence activities and the economy in the Chiquitania, which greatly depend on the forestry, agriculture and livestock sectors. Results are particularly concerning if considering the current development policies promoting frontier expansion. Departmental protected areas inhibited wildfires when strategically established in areas of high risk, even under drought conditions. However, further research is needed to assess their effectiveness accounting for more specific contextual factors. This novel and simple modelling approach can inform fire

  8. Modern pollen-rain characteristics of tall terra firme moist evergreen forest, southern Amazonia

    NASA Astrophysics Data System (ADS)

    Gosling, William D.; Mayle, Francis E.; Tate, Nicholas J.; Killeen, Timothy J.

    2005-11-01

    The paucity of modern pollen-rain data from Amazonia constitutes a significant barrier to understanding the Late Quaternary vegetation history of this globally important tropical forest region. Here, we present the first modern pollen-rain data for tall terra firme moist evergreen Amazon forest, collected between 1999 and 2001 from artificial pollen traps within a 500 × 20 m permanent study plot (14°34'50″S, 60°49'48″W) in Noel Kempff Mercado National Park (NE Bolivia). Spearman's rank correlations were performed to assess the extent of spatial and inter-annual variability in the pollen rain, whilst statistically distinctive taxa were identified using Principal Components Analysis (PCA). Comparisons with the floristic and basal area data of the plot (stems ≥10 cm d.b.h.) enabled the degree to which taxa are over/under-represented in the pollen rain to be assessed (using R-rel values). Moraceae/Urticaceae dominates the pollen rain (64% median abundance) and is also an important constituent of the vegetation, accounting for 16% of stems ≥10 cm d.b.h. and ca. 11% of the total basal area. Other important pollen taxa are Arecaceae (cf. Euterpe), Melastomataceae/Combretaceae, Cecropia, Didymopanax, Celtis, and Alchornea. However, 75% of stems and 67% of the total basal area of the plot ≥10 cm d.b.h. belong to species which are unidentified in the pollen rain, the most important of which are Phenakospermum guianensis (a banana-like herb) and the key canopy-emergent trees, Erisma uncinatum and Qualea paraensis.

  9. Tropical timber rush in Peruvian Amazonia: spatial allocation of forest concessions in an uninventoried frontier.

    PubMed

    Salo, Matti; Toivonen, Tuuli

    2009-10-01

    Land-use allocation has important implications for the conservation and management of tropical forests. Peru's forestry regime has recently been reformed and more than 7 million ha has been assigned as forest concessions. This potentially has a drastic impact on the land-use practices and species composition of the assigned areas. Nevertheless, the environmental variation found within the concessions and the process applied to delimit them are poorly studied and documented. Thus, it is difficult to estimate the biological impacts of forestry activities in concessions or plan them sustainably. This paper reveals the characteristics of the current concession allocation in Loreto, Peruvian Amazonia, using environmental and access-related variables and compares the concessions to other major land-use assignments. The work draws on a number of data sets describing land-use, ecosystem diversity, and fluvial network in the region. According to our data, certain environment types such as relatively fertile Pebas soils are overrepresented in the concessions, while others, like floodplain forests, are underrepresented in comparison to other land-use assignments. Concessions also have less anthropogenic disturbance than other areas. Furthermore, concessions are located on average further from the river network than the other land-use assignments studied. We claim that forest classification based on productivity, soil fertility, accessibility, and biodiversity patterns is an achievable long-term goal for forest authorities in Peru, and in many other tropical countries. We present a rough design of a geographic information system incorporating environmental, logging, and access-related data that could be applied to approach this goal in Peru.

  10. The Costs of Evaluating Species Densities and Composition of Snakes to Assess Development Impacts in Amazonia

    PubMed Central

    de Fraga, Rafael; Stow, Adam J.; Magnusson, William E.; Lima, Albertina P.

    2014-01-01

    Studies leading to decision-making for environmental licensing often fail to provide accurate estimates of diversity. Measures of snake diversity are regularly obtained to assess development impacts in the rainforests of the Amazon Basin, but this taxonomic group may be subject to poor detection probabilities. Recently, the Brazilian government tried to standardize sampling designs by the implementation of a system (RAPELD) to quantify biological diversity using spatially-standardized sampling units. Consistency in sampling design allows the detection probabilities to be compared among taxa, and sampling effort and associated cost to be evaluated. The cost effectiveness of detecting snakes has received no attention in Amazonia. Here we tested the effects of reducing sampling effort on estimates of species densities and assemblage composition. We identified snakes in seven plot systems, each standardised with 14 plots. The 250 m long centre line of each plot followed an altitudinal contour. Surveys were repeated four times in each plot and detection probabilities were estimated for the 41 species encountered. Reducing the number of observations, or the size of the sampling modules, caused significant loss of information on species densities and local patterns of variation in assemblage composition. We estimated the cost to find a snake as $ 120 U.S., but general linear models indicated the possibility of identifying differences in assemblage composition for half the overall survey costs. Decisions to reduce sampling effort depend on the importance of lost information to target-issues, and may not be the preferred option if there is the potential for identifying individual snake species requiring specific conservation actions. However, in most studies of human disturbance on species assemblages, it is likely to be more cost-effective to focus on other groups of organisms with higher detection probabilities. PMID:25147930

  11. A 6900-year history of landscape modification by humans in lowland Amazonia

    NASA Astrophysics Data System (ADS)

    Bush, M. B.; Correa-Metrio, A.; McMichael, C. H.; Sully, S.; Shadik, C. R.; Valencia, B. G.; Guilderson, T.; Steinitz-Kannan, M.; Overpeck, J. T.

    2016-06-01

    A sedimentary record from the Peruvian Amazon provided evidence of climate and vegetation change for the last 6900 years. Piston cores collected from the center of Lake Sauce, a 20 m deep lake at 600 m elevation, were 19.7 m in length. The fossil pollen record showed a continuously forested catchment within the period of the record, although substantial changes in forest composition were apparent. Fossil charcoal, found throughout the record, was probably associated with humans setting fires. Two fires, at c. 6700 cal BP and 4270 cal BP, appear to have been stand-replacing events possibly associated with megadroughts. The fire event at 4270 cal BP followed a drought that caused lowered lake levels for several centuries. The successional trajectories of forest recovery following these large fires were prolonged by smaller fire events. Fossil pollen of Zea mays (cultivated maize) provided evidence of agricultural activity at the site since c. 6320 cal BP. About 5150 years ago, the lake deepened and started to deposit laminated sediments. Maize agriculture reached a peak of intensity between c. 3380 and 700 cal BP. Fossil diatom data provided a proxy for lake nutrient status and productivity, both of which peaked during the period of maize cultivation. A marked change in land use was evident after c. 700 cal BP when maize agriculture was apparently abandoned at this site. Iriartea, a hyperdominant of riparian settings in western Amazonia, increased in abundance within the last 1100 years, but declined markedly at c. 1070 cal BP and again between c. 80 and -10 cal BP.

  12. Ecological speciation in the tropics: insights from comparative genetic studies in Amazonia.

    PubMed

    Beheregaray, Luciano B; Cooke, Georgina M; Chao, Ning L; Landguth, Erin L

    2014-01-01

    Evolution creates and sustains biodiversity via adaptive changes in ecologically relevant traits. Ecologically mediated selection contributes to genetic divergence both in the presence or absence of geographic isolation between populations, and is considered an important driver of speciation. Indeed, the genetics of ecological speciation is becoming increasingly studied across a variety of taxa and environments. In this paper we review the literature of ecological speciation in the tropics. We report on low research productivity in tropical ecosystems and discuss reasons accounting for the rarity of studies. We argue for research programs that simultaneously address biogeographical and taxonomic questions in the tropics, while effectively assessing relationships between reproductive isolation and ecological divergence. To contribute toward this goal, we propose a new framework for ecological speciation that integrates information from phylogenetics, phylogeography, population genomics, and simulations in evolutionary landscape genetics (ELG). We introduce components of the framework, describe ELG simulations (a largely unexplored approach in ecological speciation), and discuss design and experimental feasibility within the context of tropical research. We then use published genetic datasets from populations of five codistributed Amazonian fish species to assess the performance of the framework in studies of tropical speciation. We suggest that these approaches can assist in distinguishing the relative contribution of natural selection from biogeographic history in the origin of biodiversity, even in complex ecosystems such as Amazonia. We also discuss on how to assess ecological speciation using ELG simulations that include selection. These integrative frameworks have considerable potential to enhance conservation management in biodiversity rich ecosystems and to complement historical biogeographic and evolutionary studies of tropical biotas.

  13. CO2 and CO emission rates from three forest fire controlled experiments in Western Amazonia

    NASA Astrophysics Data System (ADS)

    Carvalho, J. A., Jr.; Amaral, S. S.; Costa, M. A. M.; Soares Neto, T. G.; Veras, C. A. G.; Costa, F. S.; van Leeuwen, T. T.; Krieger Filho, G. C.; Tourigny, E.; Forti, M. C.; Fostier, A. H.; Siqueira, M. B.; Santos, J. C.; Lima, B. A.; Cascão, P.; Ortega, G.; Frade, E. F., Jr.

    2016-06-01

    Forests represent an important role in the control of atmospheric emissions through carbon capture. However, in forest fires, the carbon stored during photosynthesis is released into the atmosphere. The carbon quantification, in forest burning, is important for the development of measures for its control. The aim of this study was to quantify CO2 and CO emissions of forest fires in Western Amazonia. In this paper, results are described of forest fire experiments conducted in Cruzeiro do Sul and Rio Branco, state of Acre, and Candeias do Jamari, state of Rondônia, Brazil. These cities are located in the Western portion of the Brazilian Amazon region. The biomass content per hectare, in the virgin forest, was measured by indirect methods using formulas with parameters of forest inventories in the central hectare of the test site. The combustion completeness was estimated by randomly selecting 10% of the total logs and twelve 2 × 2 m2 areas along three transects and examining their consumption rates by the fire. The logs were used to determine the combustion completeness of the larger materials (characteristic diameters larger than 10 cm) and the 2 × 2 m2 areas to determine the combustion completeness of small-size materials (those with characteristic diameters lower than 10 cm) and the. The overall biomass consumption by fire was estimated to be 40.0%, 41.2% and 26.2%, in Cruzeiro do Sul, Rio Branco and Candeias do Jamari, respectively. Considering that the combustion gases of carbon in open fires contain approximately 90.0% of CO2 and 10.0% of CO in volumetric basis, the average emission rates of these gases by the burning process, in the three sites, were estimated as 191 ± 46.7 t ha-1 and 13.5 ± 3.3 t ha-1, respectively.

  14. The costs of evaluating species densities and composition of snakes to assess development impacts in amazonia.

    PubMed

    Fraga, Rafael de; Stow, Adam J; Magnusson, William E; Lima, Albertina P

    2014-01-01

    Studies leading to decision-making for environmental licensing often fail to provide accurate estimates of diversity. Measures of snake diversity are regularly obtained to assess development impacts in the rainforests of the Amazon Basin, but this taxonomic group may be subject to poor detection probabilities. Recently, the Brazilian government tried to standardize sampling designs by the implementation of a system (RAPELD) to quantify biological diversity using spatially-standardized sampling units. Consistency in sampling design allows the detection probabilities to be compared among taxa, and sampling effort and associated cost to be evaluated. The cost effectiveness of detecting snakes has received no attention in Amazonia. Here we tested the effects of reducing sampling effort on estimates of species densities and assemblage composition. We identified snakes in seven plot systems, each standardised with 14 plots. The 250 m long centre line of each plot followed an altitudinal contour. Surveys were repeated four times in each plot and detection probabilities were estimated for the 41 species encountered. Reducing the number of observations, or the size of the sampling modules, caused significant loss of information on species densities and local patterns of variation in assemblage composition. We estimated the cost to find a snake as $ 120 U.S., but general linear models indicated the possibility of identifying differences in assemblage composition for half the overall survey costs. Decisions to reduce sampling effort depend on the importance of lost information to target-issues, and may not be the preferred option if there is the potential for identifying individual snake species requiring specific conservation actions. However, in most studies of human disturbance on species assemblages, it is likely to be more cost-effective to focus on other groups of organisms with higher detection probabilities.

  15. Increased Wildfire Risk Driven by Climate and Development Interactions in the Bolivian Chiquitania, Southern Amazonia.

    PubMed

    Devisscher, Tahia; Anderson, Liana O; Aragão, Luiz E O C; Galván, Luis; Malhi, Yadvinder

    2016-01-01

    Wildfires are becoming increasingly dominant in tropical landscapes due to reinforcing feedbacks between land cover change and more severe dry conditions. This study focused on the Bolivian Chiquitania, a region located at the southern edge of Amazonia. The extensive, unique and well-conserved tropical dry forest in this region is susceptible to wildfires due to a marked seasonality. We used a novel approach to assess fire risk at the regional level driven by different development trajectories interacting with changing climatic conditions. Possible future risk scenarios were simulated using maximum entropy modelling with presence-only data, combining land cover, anthropogenic and climatic variables. We found that important determinants of fire risk in the region are distance to roads, recent deforestation and density of human settlements. Severely dry conditions alone increased the area of high fire risk by 69%, affecting all categories of land use and land cover. Interactions between extreme dry conditions and rapid frontier expansion further increased fire risk, resulting in potential biomass loss of 2.44±0.8 Tg in high risk area, about 1.8 times higher than the estimates for the 2010 drought. These interactions showed particularly high fire risk in land used for 'extensive cattle ranching', 'agro-silvopastoral use' and 'intensive cattle ranching and agriculture'. These findings have serious implications for subsistence activities and the economy in the Chiquitania, which greatly depend on the forestry, agriculture and livestock sectors. Results are particularly concerning if considering the current development policies promoting frontier expansion. Departmental protected areas inhibited wildfires when strategically established in areas of high risk, even under drought conditions. However, further research is needed to assess their effectiveness accounting for more specific contextual factors. This novel and simple modelling approach can inform fire and land

  16. WRF EMS model High resolution simulations over river-urban area in Amazonia

    NASA Astrophysics Data System (ADS)

    Tota, J.; Lima, K.; Silva, R. D.; Kuhn, P. F.

    2014-12-01

    The increasing of population and size of cities in Brazil is more and more common ultimate, even in remote location like Amazon Rainforest region, e.g. Manaus, Belem. Predicting the weather and climate in large cities is remains a challenge because there are diverse processes and factors that determine or influence atmospheric condition at various time and space scales. Consequently, it is necessary to understand the mechanisms of connection between local climate (influenced by urbanization) and those due to larger scales. The weather and microclimate over Santarém city in Amazonia is poor studied and monitored. The application of meteorological models, which representing the diverse atmospheric processes at the various scales, is essential, as e.g. WRF EMS model. The addition of spatial scale data is needed for validation of these models over cities. In this paper, we describe the application of the WRF EMS model (Weather Research and Forecasting) to represent the urban-scale atmospheric conditions (1km resolution) over the Santarem city. The model was validated against observed 2 meter air temperature obtained from several points and spatial rainfall over urbanized zones of Santarém. Thermal conditions and gradients of temperature over forested and non-forested zones were clear represented by the model. The WRF model reproduces well rainfall patterns around the urban area and Tapajós river-city contacts. The main results for this model test was the Improvements in the representation of the types of land cover-Land change from the mosaics structures on the city domain, what permit all errors/bias are reduced.

  17. Learning to Question: The Roles of Multiple Hypotheses, Successive Approximations, Balloons and Toilet Paper in University Science Programs of Southwestern Amazonia

    ERIC Educational Resources Information Center

    Brown, I. Foster

    2008-01-01

    Learning to question is essential for determining pathways of conservation and development in southwestern Amazonia during a time of rapid global environmental change. Teaching such an approach in graduate science programs in regional universities can be done using play-acting and simulation exercises. Multiple working hypotheses help students…

  18. A palaeomagnetic and 40Ar/39Ar study of late precambrian sills in the SW part of the Amazonian craton: Amazonia in the Rodinia reconstruction

    NASA Astrophysics Data System (ADS)

    Elming, S.-Å.; D'Agrella-Filho, M. S.; Page, L. M.; Tohver, E.; Trindade, R. I. F.; Pacca, I. I. G.; Geraldes, M. C.; Teixeira, W.

    2009-07-01

    A new key palaeomagnetic pole (Plat. = 64.3°S, Plon. = 271.0°E, N = 14, A95 = 9.2° Q = 5) is calculated from a primary magnetization isolated in early Neoproterozoic Aguapei basic sills and dykes hosted by 1.3-1.0 Ga sedimentary rocks from the southwestern part of the Amazon craton. The characteristic remanence carried by stable, pseudo-single domain titanomagnetite shows two antipodal polarities that pass a reversals test. Magnetic anisotropy for most sites shows fabric orientations that are typical of sills, with horizontal magnetic foliations concordant to the flat-lying bedding of the host sedimentary rocks. 40Ar/39Ar analyses for one of the sills reveal a well-defined plateau age at 981 +/- 2 Myr. A tectonic reconstruction for Amazonia relative Laurentia based on this new pole `is consistent with' a position of the present northwestern part of Amazonia attached with eastern Laurentia close to Greenland at ca. 981 Ma. On basis of palaeomagnetic and geological data, we propose a scenario where Amazonia moved northeastwards along the present southeast coast of Laurentia from ca. 1200 to 980 Ma. By 980 Ma, Amazonia is placed alongside Laurentia and Baltica, in a position similar to other reconstructions of Rodinia but with a significantly different orientation.

  19. Trypanosoma cruzi in Brazilian Amazonia: Lineages TCI and TCIIa in wild primates, Rhodnius spp. and in humans with Chagas disease associated with oral transmission.

    PubMed

    Marcili, Arlei; Valente, Vera C; Valente, Sebastião A; Junqueira, Angela C V; da Silva, Flávia Maia; Pinto, Ana Yecê das Neves; Naiff, Roberto D; Campaner, Marta; Coura, José R; Camargo, Erney P; Miles, Michael A; Teixeira, Marta M G

    2009-04-01

    In this study, we provide phylogenetic and biogeographic evidence that the Trypanosoma cruzi lineages T. cruzi I (TCI) and T. cruzi IIa (TCIIa) circulate amongst non-human primates in Brazilian Amazonia, and are transmitted by Rhodnius species in overlapping arboreal transmission cycles, sporadically infecting humans. TCI presented higher prevalence rates, and no lineages other than TCI and TCIIa were found in this study in wild monkeys and Rhodnius from the Amazonian region. We characterised TCI and TCIIa from wild primates (16 TCI and five TCIIa), Rhodnius spp. (13 TCI and nine TCIIa), and humans with Chagas disease associated with oral transmission (14 TCI and five TCIIa) in Brazilian Amazonia. To our knowledge, TCIIa had not been associated with wild monkeys until now. Polymorphisms of ssrDNA, cytochrome b gene sequences and randomly amplified polymorphic DNA (RAPD) patterns clearly separated TCIIa from TCIIb-e and TCI lineages, and disclosed small intra-lineage polymorphisms amongst isolates from Amazonia. These data are important in understanding the complexity of the transmission cycles, genetic structure, and evolutionary history of T. cruzi populations circulating in Amazonia, and they contribute to both the unravelling of human infection routes and the pathological peculiarities of Chagas disease in this region.

  20. Soil-vegetation relationships on a banded ironstone 'island', Carajás Plateau, Brazilian Eastern Amazonia.

    PubMed

    Nunes, Jaquelina A; Schaefer, Carlos E G R; Ferreira Júnior, Walnir G; Neri, Andreza V; Correa, Guilherme R; Enright, Neal J

    2015-01-01

    Vegetation and soil properties of an iron-rich canga (laterite) island on the largest outcrop of banded-iron formation in Serra de Carajás (eastern Amazonia, Brazil) were studied along a topographic gradient (738-762 m asl), and analyzed to test the hypothesis that soil chemical and physical attributes play a key role in the structure and floristic composition of these plant communities. Soil and vegetation were sampled in eight replicate plots within each of the four vegetation types. Surface (0-10 cm) soil samples from each plot were analyzed for basic cations, N, P and plant species density for all species was recorded. CCA ordination analysis showed a strong separation between forest and non-forest sites on the first axis, and between herbaceous and shrubby campo rupestre on the second axis. The four vegetation types shared few plant species, which was attributed to their distinctive soil environments and filtering of their constituent species by chemical, physical and hydrological constraints. Thus, we can infer that Edaphic (pedological) factors are crucial in explaining the types and distributions of campo rupestre vegetation associated with ferruginous ironstone uplands (Canga) in Carajás, eastern Amazonia, therefore the soil properties are the main drivers of vegetation composition and structure on these ironstone islands.

  1. High genetic diversity among and within bitter manioc varieties cultivated in different soil types in Central Amazonia.

    PubMed

    Alves-Pereira, Alessandro; Peroni, Nivaldo; Cavallari, Marcelo Mattos; Lemes, Maristerra R; Zucchi, Maria Imaculada; Clement, Charles R

    2017-04-10

    Although manioc is well adapted to nutrient-poor Oxisols of Amazonia, ethnobotanical observations show that bitter manioc is also frequently cultivated in the highly fertile soils of the floodplains and Amazonian dark earths (ADE) along the middle Madeira River. Because different sets of varieties are grown in each soil type, and there are agronomic similarities between ADE and floodplain varieties, it was hypothesized that varieties grown in ADE and floodplain were more closely related to each other than either is to varieties grown in Oxisols. We tested this hypothesis evaluating the intra-varietal genetic diversity and the genetic relationships among manioc varieties commonly cultivated in Oxisols, ADE and floodplain soils. Genetic results did not agree with ethnobotanical expectation, since the relationships between varieties were variable and most individuals of varieties with the same vernacular name, but grown in ADE and floodplain, were distinct. Although the same vernacular name could not always be associated with genetic similarities, there is still a great amount of variation among the varieties. Many ecological and genetic processes may explain the high genetic diversity and differentiation found for bitter manioc varieties, but all contribute to the maintenance and amplification of genetic diversity within the manioc in Central Amazonia.

  2. On the Miocene Cyprideis species flock (Ostracoda; Crustacea) of Western Amazonia (Solimões Formation): Refining taxonomy on species level

    PubMed Central

    Gross, Martin; Ramos, Maria Ines F.; Piller, Werner E.

    2016-01-01

    The Miocene mega-wetland of western Amazonia holds a diverse, largely endemic ostracod fauna. Among them, especially the genus Cyprideis experienced a remarkable radiation. Micropalaeontologic investigations of a 400 m long sediment core (~62 km SW Benjamin Constant, Amazonia, Brazil) permitted a taxonomic revision of about two-thirds of hitherto described Cyprideis species. We evaluate the diagnostic value of shell characters and provide an extensive illustration of the intraspecific variability of species. Based on comparative morphology, the 20 recorded Cyprideis species are arranged in groups and subgroups. The “smooth” group comprises C. amazonica, C. kotzianae, C. kroemmelbeini, C. machadoi, C. multiradiata, C. olivencai, C. paralela and C. simplex; the “ornate” group C. curucae nom. nov., C. cyrtoma, C. aff. graciosa, C. inversa, C. ituiae n. sp., C. matorae n. sp., C. minipunctata, C. munoztorresi nom. nov., C. pebasae, C. reticulopunctata, C. schedogymnos and C. sulcosigmoidalis. Five species have been revalidated, two renamed, two synonymised and two are new descriptions. Along with 10 further formally established species, for which a review is pending, Cyprideis keeps at least 30 endemic species in that region during Miocene times. Up to 12 Cyprideis species have been found to occur sympatrically, representing >90 % of the entire ostracod fauna. Ostracod index species enable a biostratigraphic allocation of the well succession to the Cyprideis minipunctata to Cyprideis cyrtoma biozones, corresponding to a late Middle to early Late Miocene age (late Serravallian–early Tortonian). PMID:25543674

  3. On the Miocene Cyprideis species flock (Ostracoda; Crustacea) of Western Amazonia (Solimões Formation): Refining taxonomy on species level.

    PubMed

    Gross, Martin; Ramos, Maria Ines F; Piller, Werner E

    2014-12-18

    The Miocene mega-wetland of western Amazonia holds a diverse, largely endemic ostracod fauna. Among them, especially the genus Cyprideis experienced a remarkable radiation. Micropalaeontologic investigations of a 400 m long sediment core (~62 km SW Benjamin Constant, Amazonia, Brazil) permitted a taxonomic revision of about two-thirds of hitherto described Cyprideis species. We evaluate the diagnostic value of shell characters and provide an extensive illustration of the intraspecific variability of species. Based on comparative morphology, the 20 recorded Cyprideis species are arranged in groups and subgroups. The "smooth" group comprises C. amazonica, C. kotzianae, C. kroemmelbeini, C. machadoi, C. multiradiata, C. olivencai, C. paralela and C. simplex; the "ornate" group C. curucae nom. nov., C. cyrtoma, C. aff. graciosa, C. inversa, C. ituiae n. sp., C. matorae n. sp., C. minipunctata, C. munoztorresi nom. nov., C. pebasae, C. reticulopunctata, C. schedogymnos and C. sulcosigmoidalis. Five species have been revalidated, two renamed, two synonymised and two are new descriptions. Along with 10 further formally established species, for which a review is pending, Cyprideis keeps at least 30 endemic species in that region during Miocene times. Up to 12 Cyprideis species have been found to occur sympatrically, representing >90% of the entire ostracod fauna. Ostracod index species enable a biostratigraphic allocation of the well succession to the Cyprideis minipunctata to Cyprideis cyrtoma biozones, corresponding to a late Middle to early Late Miocene age (late Serravallian-early Tortonian).

  4. Spatial and temporal contrasts in the distribution of crops and pastures across Amazonia: A new agricultural land use data set from census data since 1950.

    PubMed

    Imbach, P; Manrow, M; Barona, E; Barretto, A; Hyman, G; Ciais, P

    2015-06-01

    Amazonia holds the largest continuous area of tropical forests with intense land use change dynamics inducing water, carbon, and energy feedbacks with regional and global impacts. Much of our knowledge of land use change in Amazonia comes from studies of the Brazilian Amazon, which accounts for two thirds of the region. Amazonia outside of Brazil has received less attention because of the difficulty of acquiring consistent data across countries. We present here an agricultural statistics database of the entire Amazonia region, with a harmonized description of crops and pastures in geospatial format, based on administrative boundary data at the municipality level. The spatial coverage includes countries within Amazonia and spans censuses and surveys from 1950 to 2012. Harmonized crop and pasture types are explored by grouping annual and perennial cropping systems, C3 and C4 photosynthetic pathways, planted and natural pastures, and main crops. Our analysis examined the spatial pattern of ratios between classes of the groups and their correlation with the agricultural extent of crops and pastures within administrative units of the Amazon, by country, and census/survey dates. Significant correlations were found between all ratios and the fraction of agricultural lands of each administrative unit, with the exception of planted to natural pastures ratio and pasture lands extent. Brazil and Peru in most cases have significant correlations for all ratios analyzed even for specific census and survey dates. Results suggested improvements, and potential applications of the database for carbon, water, climate, and land use change studies are discussed. The database presented here provides an Amazon-wide improved data set on agricultural dynamics with expanded temporal and spatial coverage.

  5. Spatial and temporal contrasts in the distribution of crops and pastures across Amazonia: A new agricultural land use data set from census data since 1950

    PubMed Central

    Imbach, P; Manrow, M; Barona, E; Barretto, A; Hyman, G; Ciais, P

    2015-01-01

    Amazonia holds the largest continuous area of tropical forests with intense land use change dynamics inducing water, carbon, and energy feedbacks with regional and global impacts. Much of our knowledge of land use change in Amazonia comes from studies of the Brazilian Amazon, which accounts for two thirds of the region. Amazonia outside of Brazil has received less attention because of the difficulty of acquiring consistent data across countries. We present here an agricultural statistics database of the entire Amazonia region, with a harmonized description of crops and pastures in geospatial format, based on administrative boundary data at the municipality level. The spatial coverage includes countries within Amazonia and spans censuses and surveys from 1950 to 2012. Harmonized crop and pasture types are explored by grouping annual and perennial cropping systems, C3 and C4 photosynthetic pathways, planted and natural pastures, and main crops. Our analysis examined the spatial pattern of ratios between classes of the groups and their correlation with the agricultural extent of crops and pastures within administrative units of the Amazon, by country, and census/survey dates. Significant correlations were found between all ratios and the fraction of agricultural lands of each administrative unit, with the exception of planted to natural pastures ratio and pasture lands extent. Brazil and Peru in most cases have significant correlations for all ratios analyzed even for specific census and survey dates. Results suggested improvements, and potential applications of the database for carbon, water, climate, and land use change studies are discussed. The database presented here provides an Amazon-wide improved data set on agricultural dynamics with expanded temporal and spatial coverage. Key Points Agricultural census database covers Amazon basin municipalities from 1950 to 2012Harmonized database groups crops and pastures by cropping system, C3/C4, and main crops

  6. Leaf Wax δ13C Varies with Elevation in the Peruvian Andes and Western Amazonia

    NASA Astrophysics Data System (ADS)

    Wu, M. S.; Feakins, S. J.; Ponton, C.; Peters, T.; West, A. J.; Galy, V.; Bentley, L. P.; Salinas, N.; Shenkin, A.; Martin, R.; Asner, G. P.; Malhi, Y.

    2015-12-01

    Plant leaf wax carbon isotopic composition (δ13Cwax) reflects the net isotopic effects associated with diffusion into the leaf, fixation of carbon by Rubisco and biosynthesis of individual leaf wax biochemicals. As declining pCO2 with elevation affects the first two fractionations, we expect to find an isotopic gradient in δ13Cwax, if the fractionation of leaf wax biosynthesis is constant. To test this, we report δ13Cwax values from 500 samples of leaves collected by tree-climbers from the upper canopy from 9 forest-inventory plots spanning a 3.5km elevation transect in the Peruvian Andes and western Amazonia during the CHAMBASA field campaign. These samples provide a unique opportunity to study the relationship between δ13Cwax and pCO2 in diverse species across this remote tropical montane forest and lowland rainforest. The very wet climate throughout (2-5 m rainfall per year) minimizes fractionation effects due to stomatal restrictions (i.e. water use efficiency) that may be an important factor elsewhere. Preliminary results show δ13Cwax values on average increase with elevation by ~1.5‰/km, a trend consistent with bulk plant δ13C in previous studies. The mean epsilon between bulk and C29 n-alkane is -7.3±2.2‰. Inter-sample differences are large on the order of 10‰. Shaded leaves and understory leaves are found to be depleted relative to sunlit leaves, presumably due to a lower photosynthetic rate and use of respired CO2 in the understory. C29 n-alkanes are on average ~2.5‰ more depleted than C30 n-alkanoic acids, indicating fractionation during selective decarboxylation. We further compare results from plants with soil and river sediments to provide insights into how leaf wax signals are archived in soils and exported from the landscape. We find a ~1.4‰/km gradient in forest soils similar to plants. We observe a ~2‰ offset between C29 n-alkane in plant leaves and in soils across the elevation profile, which is likely a signal of degradation

  7. Medicinal use of fauna by a traditional community in the Brazilian Amazonia

    PubMed Central

    2012-01-01

    Background Zootherapy inventories are important as they contribute to the world documentation of the prevalence, importance and diversity of the medicinal use of animals in traditional human communities. The present study aims to contribute with a more valuable example of the zootherapy practices of a traditional community in the Brazilian Amazonia – the “Riozinho do Anfrísio” Extractive Reserve, in Northern Brazil. Methods We used the methods of participant observation and semi-structured interviews, applied to 25 informants. We employed the combined properties of two indices to measure the medicinal importance of each cited species to the studied community, as well as their versatility in the treatment of diseases: the well known Use Value (UV) and the Medicinal Applications Value (MAV) that we developed. Results We recorded 31 species of medicinal animals from six taxonomic categories, seven of which are new to science. The species are used for the treatment of 28 diseases and one species is used as an amulet against snakebites. The five species with the highest UV indices are the most popular and valued by the studied community. Their contrasting MAV indices indicate that they have different therapeutic properties: specific (used for the treatment of few diseases; low versatility) and all-purpose (several diseases; high versatility). Similarly, the most cited diseases were also those that could be treated with a larger number of animal species. Ten species are listed in the CITES appendices and 21 are present in the IUCN Red List. The knowledge about the medicinal use of the local fauna is distributed evenly among the different age groups of the informants. Conclusions This study shows that the local fauna represents an important medicinal resource for the inhabitants of the protected area. The combined use of the UV and MAV indices allowed identifying the species with the highest therapeutic potential. This type of information about a species may be of

  8. Mayaro Virus Infection in Amazonia: A Multimodel Inference Approach to Risk Factor Assessment

    PubMed Central

    de Paula, Vanessa S.; Figueiredo, Luiz T. M.; Braga, Wornei S. M.; Luz, Sérgio L. B.

    2012-01-01

    . This suggests either a vector shift (synanthropic mosquitoes vectoring MAYV) or a habitat/habits shift (classical MAYV vectors adapting to densely populated landscapes and nocturnal biting); any such ecological/adaptive novelty could increase the likelihood of MAYV emergence in Amazonia. PMID:23071852

  9. Long term measurements of aerosol optical properties at a primary forest site in Amazonia

    NASA Astrophysics Data System (ADS)

    Rizzo, L. V.; Artaxo, P.; Müller, T.; Wiedensohler, A.; Paixão, M.; Cirino, G. G.; Arana, A.; Swietlicki, E.; Roldin, P.; Fors, E. O.; Wiedemann, K. T.; Leal, L. S. M.; Kulmala, M.

    2013-03-01

    A long term experiment was conducted in a primary forest area in Amazonia, with continuous in-situ measurements of aerosol optical properties between February 2008 and April 2011, comprising, to our knowledge, the longest database ever in the Amazon Basin. Two major classes of aerosol particles, with significantly different optical properties were identified: coarse mode predominant biogenic aerosols in the wet season (January-June), naturally released by the forest metabolism, and fine mode dominated biomass burning aerosols in the dry season (July-December), transported from regional fires. Dry particle median scattering coefficients at the wavelength of 550 nm increased from 6.3 Mm-1 to 22 Mm-1, whereas absorption at 637 nm increased from 0.5 Mm-1 to 2.8 Mm-1 from wet to dry season. Most of the scattering in the dry season was attributed to the predominance of fine mode (PM2) particles (40-80% of PM10 mass), while the enhanced absorption coefficients are attributed to the presence of light absorbing aerosols from biomass burning. As both scattering and absorption increased in the dry season, the single scattering albedo (SSA) did not show a significant seasonal variability, in average 0.86 ± 0.08 at 637 nm for dry aerosols. Measured particle optical properties were used to estimate the aerosol forcing efficiency at the top of the atmosphere. Results indicate that in this primary forest site the radiative balance was dominated by the cloud cover, particularly in the wet season. Due to the high cloud fractions, the aerosol forcing efficiency absolute values were below -3.5 W m-2 in 70% of the wet season days and in 46% of the dry season days. Besides the seasonal variation, the influence of out-of-Basin aerosol sources was observed occasionally. Periods of influence of the Manaus urban plume were detected, characterized by a consistent increase on particle scattering (factor 2.5) and absorption coefficients (factor 5). Episodes of biomass burning and mineral dust

  10. Long term measurements of aerosol optical properties at a pristine forest site in Amazonia

    NASA Astrophysics Data System (ADS)

    Rizzo, L. V.; Artaxo, P.; Müller, T.; Wiedensohler, A.; Paixão, M.; Cirino, G. G.; Arana, A.; Swietlicki, E.; Roldin, P.; Fors, E. O.; Wiedemann, K. T.; Leal, L. S. M.; Kulmala, M.

    2012-09-01

    A long term experiment was conducted in a pristine area in the Amazon forest, with continuous in situ measurements of aerosol optical properties between February 2008 and April 2011, comprising, to our knowledge, the longest database ever in Amazonia. Two types of aerosol particles, with significantly different optical properties were identified: coarse mode predominant biogenic aerosols in the wet season (January-June), naturally released by the forest metabolism, and fine mode dominated biomass burning aerosols in the dry season (July-December), transported from regional fires. Dry particle median scattering coefficients at the wavelength of 550 nm increased from 6.3 Mm-1 to 22 Mm-1, whereas absorption at 637 nm increased from 0.5 Mm-1 to 2.8 Mm-1 from wet to dry season. Most of the scattering in the dry season was attributed to the predominance of fine mode particles (40-80% of PM10 mass), while the enhanced absorption coefficients are attributed to the presence of light absorbing aerosols from biomass burning. As both scattering and absorption increased in the dry season, the single scattering albedo (SSA) did not show a significant seasonal variability, in average 0.86 ± 0.08 at 637 nm for dry particles. Measured particle optical properties were used to estimate the aerosol forcing efficiency at the top of the atmosphere. Results indicate that in this pristine forest site the radiative balance was dominated by the cloud cover, or, in other words, the aerosol indirect effect predominated over the direct effect, particularly in the wet season. Due to the high cloud fractions, the aerosol forcing efficiency was below -3.5 W m-2 in 70% of the wet season days and in 46% of the dry season days. These values are lower than the ones reported in the literature, which are based on remote sensing data. Besides the seasonal variation, the influence of external aerosol sources was observed occasionally. Periods of influence of the Manaus urban plume were detected

  11. Weather and climate impacts of biomass burning aerosols during the dry season in Amazonia

    NASA Astrophysics Data System (ADS)

    Kolusu, Seshagirirao; Marsham, John; Spracklen, Dominic; Parker, Douglas; Dalvi, Mohit; Johnson, Ben; Mann, Graham

    2016-04-01

    Amazonia is a major global source of biomass burning aerosols (BBA) with impacts on weather and climate. BBA can be represented in weather models, with satellite-observed fires used to provide emissions fields, but such emissions normally require tuning to give realistic aerosol fields in models. Here, we investigate the two-way coupling between BBA and regional weather during the South American Biomass Burning Analysis (SAMBBA) field campaign, using both a set of short-range (2-day) forecasts and nested 20-day runs with the Met Office Unified Model (MetUM). Short-range forecasts with parametrised convection show that BBA exert an overall cooling influence on the Earth-atmosphere system, although some levels of the atmosphere are directly warmed by the absorption of solar radiation: BBA reduce the clear-sky net radiation at the surface by 15 ± 1 W m-2 and reduces net top-of-atmosphere radiation by 8 ± 1 W m-2, with a direct atmospheric warming of 7 ± 1 W m-2. BBA-induced reductions in all-sky radiation are smaller in magnitude, but of the same sign. The differences in heating induced by BBA lead to a more anticyclonic circulation at 700 hPa. BBA cools the boundary layer, but warms air above, reducing the BL depth by around 19 m. Locally, on a 150 km scale, changes in precipitation reach around 4 mm day-1 due to changes in the location of convection, with BBA leading to fewer rain events that are more intense, which may be linked to the BBA changing the vertical profile of stability in the lower atmosphere. The localised changes in rainfall tend to average out to give a 5 % (0.06 mm day-1) decrease in total precipitation, but the change in regional water budget is dominated by decreased evapotranspiration from the reduced net surface fluxes (0.2 to 0.3 mm day-1). The results show that although including BBA either prognostoically, or through a climatology, improves forecasts, but differences between the impacts of prognostic and climatological aerosol are small

  12. The role of biogenic, biomass burning and urban pollution aerosol particles in controlling key atmospheric processes in Amazonia

    NASA Astrophysics Data System (ADS)

    Artaxo, P.; Ferreira De Brito, J.; Barbosa, H. M.; Rizzo, L. V.; Sena, E. T.; Cirino, G.; Arana, A.; Yanez-Serrano, A. M.

    2013-05-01

    As part of the LBA (The Large Scale Biosphere Atmosphere Experiment in Amazonia) experiment, a research program run in the last 10 years had help to understand critical atmospheric processes in Amazonia. The vegetation in Amazonia is a direct source of aerosol particles to the atmosphere as well as a source of biogenic trace gases that generates particles trough gas-to-particle conversion. Biomass burning is also a large source of particles and trace gases to the atmosphere. Over the last 10 years, the LBA experiment has unveiled several key processes that control Amazonian composition and influence regional climate. A significant fraction (60-80%) of airborne particles can act as Cloud Condensation Nuclei (CCN), influencing cloud formation and development. The radiation balance is strongly influenced by biomass burning particles, and surface radiative forcing up to -250 w/m2 is measured. A network of 8 sites with AERONET sunphotometers measures aerosol optical depth (AOD) and derive aerosol size distribution and optical properties. Aerosols are composed of more than 70% of organic material, with significant absorption characteristics. The aerosol radiative forcing during the biomass burning season can reach very high values, and the increase in diffuse radiation increases the carbon uptake by the forest for AOD values smaller than 1.2 at 500nm. For large AOD, the solar flux is strongly reduced making the carbon uptake approach zero for AOD larger than 3.0. The composition of aerosols is mostly organic, with contribution of K, Ca, Si, and other trace elements. The aerosol has high capability to serve as Cloud Condensation Nuclei (CCN), contributing with high water vapor amounts to the significant cloud cover over the region. In the last 20 years, an urbanization process took over for most of the Amazonian region, increasing urban pollution that interacts with forest emissions to produce a quite unique pattern of aerosols and pollutants around large urban areas such

  13. Recent Extremes of Drought and Flooding in Amazonia in the context of long term climate variability: Vulnerabilities and Human Adaptation

    NASA Astrophysics Data System (ADS)

    Marengo, J. A.; Borma, L. S.; Rodriguez, D. A.; Pinho, P.; Soares, W. R.; Alves, L. M.

    2013-12-01

    The present study focuses on the analyses of extreme drought and flooding situations in Amazonia, using level/discharge data from some rivers in the Amazon region as indicators of impacts. The last 10 years have featured various 'once in a century' droughts and floods in the Amazon basin, which have affected human and natural systems in the region. We assess a history of such hazards based on river data, and discuss some of the observed impacts in terms of vulnerability of human and natural systems, as well as some of adaptation strategies implemented by regional and local governments to cope with them. A critical perspective of mitigation of drought and flood policies in Amazonia suggests that they have been mostly ineffective in reducing vulnerability for the majority of the population. The last seven years have featured severe droughts and floods in Amazonia, with some of these events being characterized at the time as 'once-in-a-century' seasonal extremes. Most of these events were classified as such using river data statistics. Flood and drought hazards represent the integrated impacts due to changes in rainfall across the basin. The record flooding in the Amazon in 2012 surpassed the previous record extreme of 2009, and river levels during the droughts of 2005 and 2010 were among the lowest during the last 40 years. Droughts and floods, part of the natural climate variability inthose regions, have occurred in the past and will continue to occur in the future. The inhabitants of the region are well adapted to this hydrological interannual dynamics and, over time, have been able to develop their livelihood strategies in an 'optimum manner'. Hydrological extremes affect not only human activities and economy but also ecosystems, with large potential impacts on regional biogeochemical and carbon cycles, particularly during droughts due to forest fires and biomass burning. Various studies have shown that interannual variability of rainfall and river levels in the

  14. Disentangling the contribution of multiple land covers to fire-mediated carbon emissions in Amazonia during the 2010 drought

    NASA Astrophysics Data System (ADS)

    Anderson, Liana Oighenstein; Aragão, Luiz E. O. C.; Gloor, Manuel; Arai, Egídio; Adami, Marcos; Saatchi, Sassan S.; Malhi, Yadvinder; Shimabukuro, Yosio E.; Barlow, Jos; Berenguer, Erika; Duarte, Valdete

    2015-10-01

    In less than 15 years, the Amazon region experienced three major droughts. Links between droughts and fires have been demonstrated for the 1997/1998, 2005, and 2010 droughts. In 2010, emissions of 510 ± 120 Tg C were associated to fire alone in Amazonia. Existing approaches have, however, not yet disentangled the proportional contribution of multiple land cover sources to this total. We develop a novel integration of multisensor and multitemporal satellite-derived data on land cover, active fires, and burned area and an empirical model of fire-induced biomass loss to quantify the extent of burned areas and resulting biomass loss for multiple land covers in Mato Grosso (MT) state, southern Amazonia—the 2010 drought most impacted region. We show that 10.77% (96,855 km2) of MT burned. We estimated a gross carbon emission of 56.21 ± 22.5 Tg C from direct combustion of biomass, with an additional 29.4 ± 10 Tg C committed to be emitted in the following years due to dead wood decay. It is estimated that old-growth forest fires in the whole Brazilian Legal Amazon (BLA) have contributed to 14.81 Tg of C (11.75 Tg C to 17.87 Tg C) emissions to the atmosphere during the 2010 fire season, with an affected area of 27,555 km2. Total C loss from the 2010 fires in MT state and old-growth forest fires in the BLA represent, respectively, 77% (47% to 107%) and 86% (68.2% to 103%) of Brazil's National Plan on Climate Change annual target for Amazonia C emission reductions from deforestation.

  15. Increased dry-season length over southern Amazonia in recent decades and its implication for future climate projection

    PubMed Central

    Fu, Rong; Yin, Lei; Li, Wenhong; Arias, Paola A.; Dickinson, Robert E.; Huang, Lei; Chakraborty, Sudip; Fernandes, Katia; Liebmann, Brant; Fisher, Rosie; Myneni, Ranga B.

    2013-01-01

    We have observed that the dry-season length (DSL) has increased over southern Amazonia since 1979, primarily owing to a delay of its ending dates (dry-season end, DSE), and is accompanied by a prolonged fire season. A poleward shift of the subtropical jet over South America and an increase of local convective inhibition energy in austral winter (June–August) seem to cause the delay of the DSE in austral spring (September–November). These changes cannot be simply linked to the variability of the tropical Pacific and Atlantic Oceans. Although they show some resemblance to the effects of anthropogenic forcings reported in the literature, we cannot attribute them to this cause because of inadequate representation of these processes in the global climate models that were presented in the Intergovernmental Panel on Climate Change’s Fifth Assessment Report. These models significantly underestimate the variability of the DSE and DSL and their controlling processes. Such biases imply that the future change of the DSE and DSL may be underestimated by the climate projections provided by the Intergovernmental Panel on Climate Change’s Fifth Assessment Report models. Although it is not clear whether the observed increase of the DSL will continue in the future, were it to continue at half the rate of that observed, the long DSL and fire season that contributed to the 2005 drought would become the new norm by the late 21st century. The large uncertainty shown in this study highlights the need for a focused effort to better understand and simulate these changes over southern Amazonia. PMID:24145443

  16. Convergent Adaptations: Bitter Manioc Cultivation Systems in Fertile Anthropogenic Dark Earths and Floodplain Soils in Central Amazonia

    PubMed Central

    Fraser, James Angus; Alves-Pereira, Alessandro; Junqueira, André Braga; Peroni, Nivaldo; Clement, Charles Roland

    2012-01-01

    Shifting cultivation in the humid tropics is incredibly diverse, yet research tends to focus on one type: long-fallow shifting cultivation. While it is a typical adaptation to the highly-weathered nutrient-poor soils of the Amazonian terra firme, fertile environments in the region offer opportunities for agricultural intensification. We hypothesized that Amazonian people have developed divergent bitter manioc cultivation systems as adaptations to the properties of different soils. We compared bitter manioc cultivation in two nutrient-rich and two nutrient-poor soils, along the middle Madeira River in Central Amazonia. We interviewed 249 farmers in 6 localities, sampled their manioc fields, and carried out genetic analysis of bitter manioc landraces. While cultivation in the two richer soils at different localities was characterized by fast-maturing, low-starch manioc landraces, with shorter cropping periods and shorter fallows, the predominant manioc landraces in these soils were generally not genetically similar. Rather, predominant landraces in each of these two fertile soils have emerged from separate selective trajectories which produced landraces that converged for fast-maturing low-starch traits adapted to intensified swidden systems in fertile soils. This contrasts with the more extensive cultivation systems found in the two poorer soils at different localities, characterized by the prevalence of slow-maturing high-starch landraces, longer cropping periods and longer fallows, typical of previous studies. Farmers plant different assemblages of bitter manioc landraces in different soils and the most popular landraces were shown to exhibit significantly different yields when planted in different soils. Farmers have selected different sets of landraces with different perceived agronomic characteristics, along with different fallow lengths, as adaptations to the specific properties of each agroecological micro-environment. These findings open up new avenues for

  17. Convergent adaptations: bitter manioc cultivation systems in fertile anthropogenic dark earths and floodplain soils in Central Amazonia.

    PubMed

    Fraser, James Angus; Alves-Pereira, Alessandro; Junqueira, André Braga; Peroni, Nivaldo; Clement, Charles Roland

    2012-01-01

    Shifting cultivation in the humid tropics is incredibly diverse, yet research tends to focus on one type: long-fallow shifting cultivation. While it is a typical adaptation to the highly-weathered nutrient-poor soils of the Amazonian terra firme, fertile environments in the region offer opportunities for agricultural intensification. We hypothesized that Amazonian people have developed divergent bitter manioc cultivation systems as adaptations to the properties of different soils. We compared bitter manioc cultivation in two nutrient-rich and two nutrient-poor soils, along the middle Madeira River in Central Amazonia. We interviewed 249 farmers in 6 localities, sampled their manioc fields, and carried out genetic analysis of bitter manioc landraces. While cultivation in the two richer soils at different localities was characterized by fast-maturing, low-starch manioc landraces, with shorter cropping periods and shorter fallows, the predominant manioc landraces in these soils were generally not genetically similar. Rather, predominant landraces in each of these two fertile soils have emerged from separate selective trajectories which produced landraces that converged for fast-maturing low-starch traits adapted to intensified swidden systems in fertile soils. This contrasts with the more extensive cultivation systems found in the two poorer soils at different localities, characterized by the prevalence of slow-maturing high-starch landraces, longer cropping periods and longer fallows, typical of previous studies. Farmers plant different assemblages of bitter manioc landraces in different soils and the most popular landraces were shown to exhibit significantly different yields when planted in different soils. Farmers have selected different sets of landraces with different perceived agronomic characteristics, along with different fallow lengths, as adaptations to the specific properties of each agroecological micro-environment. These findings open up new avenues for

  18. [Distribution patterns of canopy and understory tree species at local scale in a Tierra Firme forest, the Colombian Amazonia].

    PubMed

    Barreto-Silva, Juan Sebastian; López, Dairon Cárdenas; Montoya, Alvaro Javier Duque

    2014-03-01

    The effect of environmental variation on the structure of tree communities in tropical forests is still under debate. There is evidence that in landscapes like Tierra Firme forest, where the environmental gradient decreases at a local level, the effect of soil on the distribution patterns of plant species is minimal, happens to be random or is due to biological processes. In contrast, in studies with different kinds of plants from tropical forests, a greater effect on floristic composition of varying soil and topography has been reported. To assess this, the current study was carried out in a permanent plot of ten hectares in the Amacayacu National Park, Colombian Amazonia. To run the analysis, floristic and environmental variations were obtained according to tree species abundance categories and growth forms. In order to quantify the role played by both environmental filtering and dispersal limitation, the variation of the spatial configuration was included. We used Detrended Correspondence Analysis and Canonical Correspondence Analysis, followed by a variation partitioning, to analyze the species distribution patterns. The spatial template was evaluated using the Principal Coordinates of Neighbor Matrix method. We recorded 14 074 individuals from 1 053 species and 80 families. The most abundant families were Myristicaceae, Moraceae, Meliaceae, Arecaceae and Lecythidaceae, coinciding with other studies from Northwest Amazonia. Beta diversity was relatively low within the plot. Soils were very poor, had high aluminum concentration and were predominantly clayey. The floristic differences explained along the ten hectares plot were mainly associated to biological processes, such as dispersal limitation. The largest proportion of community variation in our dataset was unexplained by either environmental or spatial data. In conclusion, these results support random processes as the major drivers of the spatial variation of tree species at a local scale on Tierra Firme

  19. Increased dry-season length over southern Amazonia in recent decades and its implication for future climate projection.

    PubMed

    Fu, Rong; Yin, Lei; Li, Wenhong; Arias, Paola A; Dickinson, Robert E; Huang, Lei; Chakraborty, Sudip; Fernandes, Katia; Liebmann, Brant; Fisher, Rosie; Myneni, Ranga B

    2013-11-05

    We have observed that the dry-season length (DSL) has increased over southern Amazonia since 1979, primarily owing to a delay of its ending dates (dry-season end, DSE), and is accompanied by a prolonged fire season. A poleward shift of the subtropical jet over South America and an increase of local convective inhibition energy in austral winter (June-August) seem to cause the delay of the DSE in austral spring (September-November). These changes cannot be simply linked to the variability of the tropical Pacific and Atlantic Oceans. Although they show some resemblance to the effects of anthropogenic forcings reported in the literature, we cannot attribute them to this cause because of inadequate representation of these processes in the global climate models that were presented in the Intergovernmental Panel on Climate Change's Fifth Assessment Report. These models significantly underestimate the variability of the DSE and DSL and their controlling processes. Such biases imply that the future change of the DSE and DSL may be underestimated by the climate projections provided by the Intergovernmental Panel on Climate Change's Fifth Assessment Report models. Although it is not clear whether the observed increase of the DSL will continue in the future, were it to continue at half the rate of that observed, the long DSL and fire season that contributed to the 2005 drought would become the new norm by the late 21st century. The large uncertainty shown in this study highlights the need for a focused effort to better understand and simulate these changes over southern Amazonia.

  20. Seasonality of isoprenoid emissions from a primary rainforest in central Amazonia

    NASA Astrophysics Data System (ADS)

    Alves, Eliane G.; Jardine, Kolby; Tota, Julio; Jardine, Angela; Yãnez-Serrano, Ana Maria; Karl, Thomas; Tavares, Julia; Nelson, Bruce; Gu, Dasa; Stavrakou, Trissevgeni; Martin, Scot; Artaxo, Paulo; Manzi, Antonio; Guenther, Alex

    2016-03-01

    Tropical rainforests are an important source of isoprenoid and other volatile organic compound (VOC) emissions to the atmosphere. The seasonal variation of these compounds is however still poorly understood. In this study, vertical profiles of mixing ratios of isoprene, total monoterpenes and total sesquiterpenes, were measured within and above the canopy, in a primary rainforest in central Amazonia, using a proton transfer reaction - mass spectrometer (PTR-MS). Fluxes of these compounds from the canopy into the atmosphere were estimated from PTR-MS measurements by using an inverse Lagrangian transport model. Measurements were carried out continuously from September 2010 to January 2011, encompassing the dry and wet seasons. Mixing ratios were higher during the dry (isoprene - 2.68 ± 0.9 ppbv, total monoterpenes - 0.67 ± 0.3 ppbv; total sesquiterpenes - 0.09 ± 0.07 ppbv) than the wet season (isoprene - 1.66 ± 0.9 ppbv, total monoterpenes - 0.47 ± 0.2 ppbv; total sesquiterpenes - 0.03 ± 0.02 ppbv) for all compounds. Ambient air temperature and photosynthetically active radiation (PAR) behaved similarly. Daytime isoprene and total monoterpene mixing ratios were highest within the canopy, rather than near the ground or above the canopy. By comparison, daytime total sesquiterpene mixing ratios were highest near the ground. Daytime fluxes varied significantly between seasons for all compounds. The maximums for isoprene (2.53 ± 0.5 µmol m-2 h-1) and total monoterpenes (1.77 ± 0.05 µmol m-2 h-1) were observed in the late dry season, whereas the maximum for total sesquiterpenes was found during the dry-to-wet transition season (0.77 ± 0.1 µmol m-2 h-1). These flux estimates suggest that the canopy is the main source of isoprenoids emitted into the atmosphere for all seasons. However, uncertainties in turbulence parameterization near the ground could affect estimates of fluxes that come from the ground. Leaf phenology seemed to be an important driver of seasonal

  1. New geological framework for Western Amazonia (Brazil) and implications for biogeography and evolution

    NASA Astrophysics Data System (ADS)

    de Fátima Rossetti, Dilce; Mann de Toledo, Peter; Góes, Ana Maria

    2005-01-01

    associated with a lake system (i.e., fan-delta) and/or fluvial flood plain areas. After a period of erosion, a fluvial system with eastward draining channels started to develop at around 27,000 14C yr B.P. The fluvial channels were overflooded in mid-Holocene time. This flooding is attributed to an increased period of humidity, with a peak between 5000 and 2500 14C yr B.P. The data presented herein support that, rather than being a monotonous area, the Amazonia was a place with frequent changes in landscape throughout the Neogene-Quaternary, probably as a result of climatic and tectonic factors. We hypothesize that these changes in the physical environment stressed the biota, resulting in speciation and thus had a great impact on modern biodiversity.

  2. Austroboletus amazonicus sp. nov. and Fistulinella campinaranae var. scrobiculata, two commonly occurring boletes from a forest dominated by Pseudomonotes tropenbosii (Dipterocarpaceae) in Colombian Amazonia.

    PubMed

    da Marcela Vasco-Palacios, Aí; López-Quintero, Carlos; Franco-Molano, Ana Esperanza; Boekhout, Teun

    2014-01-01

    Two boletes that frequently form fruiting bodies in Pseudomonotes tropenbosii forests are described from Colombian Amazonia. One is a new species of Austroboletus here described as A. amazonicus and the other one is Fistulinella campinaranae var. scrobiculata Singer, which is a new record for Colombia. Macromorphological, micromorphological and habitat data for these species are provided as well as DNA sequence data of the internal transcribed spacer (ITS) regions and the D1/D2 domains of the large subunit (LSU) ribosomal DNA.

  3. Taxonomy and distribution of the salamander genus Bolitoglossa Duméril, Bibron & Duméril, 1854 (Amphibia, Caudata, Plethodontidae) in Brazilian Amazonia.

    PubMed

    Brcko, Isabela Carvalho; Hoogmoed, Marinus Steven; Neckel-Oliverira, Selvino

    2013-01-01

    For nearly 40 years Bolitoglossa paraensis has been synonymized with Bolitoglossa altamazonica. This fact has been mainly related to taxonomic ambiguities arising from the morphological similarities between these species and the scarcity of material deposited in collections. However, during the past 30 years new material of Bolitoglossa has been collected in many places throughout the Brazilian Amazonia, including the type locality of B. paraensis, Santa Isabel do Pará. In this article we designate the neotype of B. paraensis based on new material from the type locality, correct misinterpretations about this name. We determined how many species of the genus Bolitoglossa occur in Brazilian Amazonia, described three new species, B. caldwellae sp. nov., B. madeira sp. nov., and B. tapajonica sp. nov., provide a key for identifying Brazilian salamanders. Were analyzed two hundred and seventy eight specimens of Bolitoglossa from the Brazilian states of Acre, Amapá, Amazonas, Pará, and Rondonia; morphological data ofB. altamazonica from Colombia were used for comparison purposes. We confirm the presence of B. altamazonica in extreme western Brazil, and expand the number of species occurring in Brazilian Amazonia to five.

  4. Extensive Holocene tropical peat and carbon accumulation within a subsiding intraforeland basin (Pastaza fan and Ucamara floodbasin), Peruvian Amazonia

    NASA Astrophysics Data System (ADS)

    Lähteenoja, Outi; Räsänen, Matti; Rojas Reátegui, Yully; Del Castillo, Dennis; Oinonen, Markku

    2010-05-01

    Several studies discuss the role of the Amazon Basin in the global carbon cycle, but the existence of extensive tropical peat deposits in lowland Amazonia has been suggested only recently. These up to 5.9 m thick peat deposits documented from a floodplain environment in Western Amazonia have accumulated at high rates (0.94-4.88 mm per year) acting as a strong carbon sink (Lähteenoja et al. 2009). The tectonic environment of Western Amazonia is a foreland belt formed during the uplift of the Andes Mountains as a result of shallow subduction and compressive foreland shortening (Räsänen et al. 1987, Dumont 1996). These foreland basins are characterized by high subsidence rates, up to 4-11 km of sediment deposits as well as river aggradation and avulsions (Räsänen et al. 1987). We studied peat and carbon accumulation in the Pastaza-Marañón intraforeland basin, which consists of the volcanogenic Pastaza alluvial fan and the Ucamara meandering river floodbasin. Together, they form the largest modern tropical system of fluvial aggradation, whose potential to accumulate peat is considerable. In 13 wetland sites detected in Landsat TM satellite images, we measured peat thickness along a transect and collected peat samples for determination of total organic content, carbon content, dry bulk density, AMS radiocarbon age and peat and carbon accumulation rates. According to the results, the Pastaza fan and the Ucamara floodbasin harbor thick peatlands, whose existence has not been previously discussed. All the study sites had either a continuous peat deposit over clastic sediments or a complex stratigraphy of successive layers of clastic sediments, clayey peat and pure peat. Thickness of these heterogeneous deposits varied from 0.20 to 7.5 m. Bulk density, total organic content and carbon content varied from 0.01 to 0.26 g/cm3, from 37 to 99 %, and from 19 to 59 %, respectively. The complex stratigraphies (encountered especially in the Ucamara floodbasin) are obviously

  5. Aerosol and precipitation chemistry measurements in a remote site in Central Amazonia: the role of biogenic contribution

    NASA Astrophysics Data System (ADS)

    Pauliquevis, T.; Lara, L. L.; Antunes, M. L.; Artaxo, P.

    2012-06-01

    In this analysis a 3.5 years data set of aerosol and precipitation chemistry, obtained in a remote site in Central Amazonia (Balbina, (1°55' S, 59°29' W, 174 m a.s.l.), about 200 km north of Manaus) is discussed. Aerosols were sampled using stacked filter units (SFU), which separate fine (d < 2.5 μm) and coarse mode (2.5 μm < d < 10.0 μm) aerosol particles. Filters were analyzed for particulate mass (PM), Equivalent Black Carbon (BCE) and elemental composition by Particle Induced X-Ray Emission (PIXE). Rainwater samples were collected using a wet-only sampler and samples were analyzed for pH and ionic composition, which was determined using ionic chromatography (IC). Natural sources dominated the aerosol mass during the wet season, when it was predominantly of natural biogenic origin mostly in the coarse mode, which comprised up to 81% of PM10. Biogenic aerosol from both primary emissions and secondary organic aerosol dominates the fine mode in the wet season, with very low concentrations (average 2.2 μg m-3). Soil dust was responsible for a minor fraction of the aerosol mass (less than 17%). Sudden increases in the concentration of elements as Al, Ti and Fe were also observed, both in fine and coarse mode (mostly during the April-may months), which we attribute to episodes of Saharan dust transport. During the dry periods, a significant contribution to the fine aerosols loading was observed, due to the large-scale transport of smoke from biomass burning in other portions of the Amazon basin. This contribution is associated with the enhancement of the concentration of S, K, Zn and BCE. Chlorine, which is commonly associated to sea salt and also to biomass burning emissions, presented higher concentration not only during the dry season but also for the April-June months, due to the establishment of more favorable meteorological conditions to the transport of Atlantic air masses to Central Amazonia. The chemical composition of rainwater was similar to those

  6. Neotropics provide insights into the emergence of New World monkeys: New dental evidence from the late Oligocene of Peruvian Amazonia.

    PubMed

    Marivaux, Laurent; Adnet, Sylvain; Altamirano-Sierra, Ali J; Boivin, Myriam; Pujos, François; Ramdarshan, Anusha; Salas-Gismondi, Rodolfo; Tejada-Lara, Julia V; Antoine, Pierre-Olivier

    2016-08-01

    Recent field efforts in Peruvian Amazonia (Contamana area, Loreto Department) have resulted in the discovery of a late Oligocene (ca. 26.5 Ma; Chambira Formation) fossil primate-bearing locality (CTA-61). In this paper, we analyze the primate material consisting of two isolated upper molars, the peculiar morphology of which allows us to describe a new medium-sized platyrrhine monkey: Canaanimico amazonensis gen. et sp. nov. In addition to the recent discovery of Perupithecus ucayaliensis, a primitive anthropoid taxon of African affinities from the alleged latest Eocene Santa Rosa locality (Peruvian Amazonia), the discovery of Canaanimico adds to the evidence that primates were well-established in the Amazonian Basin during the Paleogene. Our phylogenetic results based on dental evidence show that none of the early Miocene Patagonian taxa (Homunculus, Carlocebus, Soriacebus, Mazzonicebus, Dolichocebus, Tremacebus, and Chilecebus), the late Oligocene Bolivian Branisella, or the Peruvian Canaanimico, is nested within a crown platyrrhine clade. All these early taxa are closely related and considered here as stem Platyrrhini. Canaanimico is nested within the Patagonian Soriacebinae, and closely related to Soriacebus, thereby extending back the soriacebine lineage to 26.5 Ma. Given the limited dental evidence, it is difficult to assess if Canaanimico was engaged in a form of pitheciine-like seed predation as is observed in Soriacebus and Mazzonicebus, but dental microwear patterns recorded on one upper molar indicate that Canaanimico was possibly a fruit and hard-object eater. If Panamacebus, a recently discovered stem cebine from the early Miocene of Panama, indicates that the crown platyrrhine radiation was already well underway by the earliest Miocene, Canaanimico indicates in turn that the "homunculid" radiation (as a part of the stem radiation) was well underway by the late Oligocene. These new data suggest that the stem radiation likely occurred in the Neotropics

  7. On the Onset of the Rainy Season in Amazonia: WHAT the Observations Show, and Why the Biases in Climate Models?

    NASA Astrophysics Data System (ADS)

    Marengo, J. A.; Alves, L. M.; Fu, R.

    2014-12-01

    The onset of the Amazon rainy season shows a large temporal and spatial variability, delays on the date of the onset will have strong impacts on local agriculture, hydroelectric power generation as well as on the hydrology of large rivers. Two "once-in-a-century" droughts occurred in 2005 and 2010, and it was shown that in those events the rainy season started later than normal, and also that on the last 10 years the dry season has increased in length by about one month. These events highlight the urgency for improving our understanding and capability to model onset of the rainy season and drought variability, for the present and future. Most studies have attributed the variability of the rainy season onset over Amazonia to the variability of the tropical oceans whether other factors, such as climate change, land use and aerosols also contribute to the variability are not clear.. Global climate models run on seasonal climate forecast mode still show large uncertainties on the prediction of onset of seasonal rains. As for climate change, the CMIP3 and CMIP5 appear to underestimate the past variability, and also project virtually no future change of the onset of rainy season over the Amazon even when they are forced by strong greenhouse forcing under the RCP8.5 emission scenario. Why these models underestimate the variability of the rainy season onset, and whether this bias implies an underestimate of sensitivity of their dry season length to anthropogenic radiative forcing remain unclear. This FAPESP DOE grant 2013/50538 aims to explore use of the measurements provided by the Atmospheric Radiation Measurement (ARM) Mobile Facilities (AMF)-GoAmazon and the Cloud processes of the main precipitation systems in Brazil (CHUVA) Field Experiments, along with global and regional model experiments, to explore the sources of the above described uncertainty. The project will address several issues, i.e. the inadequate representation of the types of convection (i.e., maritime

  8. A Spatial Probit Econometric Model of Land Change: The Case of Infrastructure Development in Western Amazonia, Peru.

    PubMed

    Arima, E Y

    2016-01-01

    Tropical forests are now at the center stage of climate mitigation policies worldwide given their roles as sources of carbon emissions resulting from deforestation and forest degradation. Although the international community has created mechanisms such as REDD+ to reduce those emissions, developing tropical countries continue to invest in infrastructure development in an effort to spur economic growth. Construction of roads in particular is known to be an important driver of deforestation. This article simulates the impact of road construction on deforestation in Western Amazonia, Peru, and quantifies the amount of carbon emissions associated with projected deforestation. To accomplish this objective, the article adopts a Bayesian probit land change model in which spatial dependencies are defined between regions or groups of pixels instead of between individual pixels, thereby reducing computational requirements. It also compares and contrasts the patterns of deforestation predicted by both spatial and non-spatial probit models. The spatial model replicates complex patterns of deforestation whereas the non-spatial model fails to do so. In terms of policy, both models suggest that road construction will increase deforestation by a modest amount, between 200-300 km2. This translates into aboveground carbon emissions of 1.36 and 1.85 x 106 tons. However, recent introduction of palm oil in the region serves as a cautionary example that the models may be underestimating the impact of roads.

  9. Exploring different scenarios of land use policy and their impacts on provision of ecosystem services in Amazonia

    NASA Astrophysics Data System (ADS)

    von Randow, C.; Aguiar, A. P. D.; Thonicke, K.; Verbeeck, H.; Guimberteau, M.; Langerwisch, F.; Rammig, A.; Galbraith, D.; Maksic, J.; Kruijt, B.

    2014-12-01

    A great challenge faced by the Amazon region is to maintain the ecosystem services provided by the pristine forest and its complex ecological processes, as well as the needs of the growing human population in the region, in face of global environmental changes and growing demands for land use. In the present study we analyze two different storylines linking different land use scenarios to possible impacts on the provision of ecosystem services in Amazonia: 1) a sustainable, environmental development scenario and 2) a chaotic, uncontrollable deforestation scenario. The future land cover maps are projected by a spatially explicit, dynamic land use model (LuccME) and are then used as inputs, in combination with climate change scenarios, to drive four biosphere models (INLAND, ORCHIDEE, JULES and LPJ). The biosphere models simulate changes in evapotranspiration and carbon fluxes and stocks. Finally, overlaying the biosphere model outputs with maps of roads or protected areas in the region, we analyze how the two land use scenarios will possibly affect the provision of key ecosystem services in the region.

  10. A Spatial Probit Econometric Model of Land Change: The Case of Infrastructure Development in Western Amazonia, Peru

    PubMed Central

    Arima, E. Y.

    2016-01-01

    Tropical forests are now at the center stage of climate mitigation policies worldwide given their roles as sources of carbon emissions resulting from deforestation and forest degradation. Although the international community has created mechanisms such as REDD+ to reduce those emissions, developing tropical countries continue to invest in infrastructure development in an effort to spur economic growth. Construction of roads in particular is known to be an important driver of deforestation. This article simulates the impact of road construction on deforestation in Western Amazonia, Peru, and quantifies the amount of carbon emissions associated with projected deforestation. To accomplish this objective, the article adopts a Bayesian probit land change model in which spatial dependencies are defined between regions or groups of pixels instead of between individual pixels, thereby reducing computational requirements. It also compares and contrasts the patterns of deforestation predicted by both spatial and non-spatial probit models. The spatial model replicates complex patterns of deforestation whereas the non-spatial model fails to do so. In terms of policy, both models suggest that road construction will increase deforestation by a modest amount, between 200–300 km2. This translates into aboveground carbon emissions of 1.36 and 1.85 x 106 tons. However, recent introduction of palm oil in the region serves as a cautionary example that the models may be underestimating the impact of roads. PMID:27010739

  11. Distribution and abundance of white-fronted spider monkeys, Ateles belzebuth (Atelidae), and threats to their survival in Peruvian Amazonia.

    PubMed

    Aquino, Rolando; Cornejo, Fanny M; Pezo, Etersit; Heymann, Eckhard W

    2013-01-01

    The white-fronted spider monkey, Ateles belzebuth, is listed as 'Endangered' according to the IUCN classification. In Peru it is found in the departments of Loreto, San Martín, Amazonas and Cajamarca, but detailed data on its geographic distribution, population densities and conservation status are scarce. In order to obtain such information, we conducted transect censuses on the Río Aushiri and Río San Antonio (right bank of Río Napo), and between the Río Curaray and the Río Arabela and Río Nashiño, respectively, and made additional explorations on the northern and southern banks of the Río Marañón. We obtained 48 sightings along 761 km of census transect. Group size and population densities were lower in an area with high hunting pressure compared to areas with medium or low hunting pressure. Besides hunting, increasing deforestation is a major threat to the survival of A. belzebuth in Peruvian Amazonia.

  12. Prehistorically modified soils of central Amazonia: a model for sustainable agriculture in the twenty-first century.

    PubMed

    Glaser, Bruno

    2007-02-28

    Terra Preta soils of central Amazonia exhibit approximately three times more soil organic matter, nitrogen and phosphorus and 70 times more charcoal compared to adjacent infertile soils. The Terra Preta soils were generated by pre-Columbian native populations by chance or intentionally adding large amounts of charred residues (charcoal), organic wastes, excrements and bones. In this paper, it is argued that generating new Terra Preta sites ('Terra Preta nova') could be the basis for sustainable agriculture in the twenty-first century to produce food for billions of people, and could lead to attaining three Millennium Development Goals: (i) to combat desertification, (ii) to sequester atmospheric CO2 in the long term, and (iii) to maintain biodiversity hotspots such as tropical rainforests. Therefore, large-scale generation and utilization of Terra Preta soils would decrease the pressure on primary forests that are being extensively cleared for agricultural use with only limited fertility and sustainability and, hence, only providing a limited time for cropping. This would maintain biodiversity while mitigating both land degradation and climate change. However, it should not be overlooked that the infertility of most tropical soils (and associated low population density) is what could have prevented tropical forests undergoing large-scale clearance for agriculture. Increased fertility may increase the populations supported by shifting cultivation, thereby maintaining and increasing pressure on forests.

  13. HBV/HDV co-infection in the Western Brazilian Amazonia: an intriguing mutation among HDV genotype 3 carriers.

    PubMed

    Kay, A; Melo da Silva, E; Pedreira, H; Negreiros, S; Lobato, C; Braga, W; Muwonge, R; Dény, P; Reis, M; Zoulim, F; Trepo, C; D'Oliveira, A; Salcedo, J M; Schinoni, M I; Parana, R

    2014-12-01

    HDV infection still remains a serious public health problem in Amazonia. There are few data regarding the biomolecular aspects of HBV/HDV co-infection in this region. We studied 92 patients HBsAg(+) /anti-HDV IgG(+) followed at the Hepatitis Referral Centers of Porto Velho (RO), Rio Branco and Cruzeiro do Sul (AC), Brazil, from March 2006 to March 2007 for whom the HDV and/or the HBV genotype could be determined. The HDV genotype could be determined in 90 patients, while the HBV genotypes could be positively determined in 74. HBV subgenotype F2 is the most prevalent (40.2%), followed by the subgenotypes A1 (15.2%) and D3 (8.7%), while 16.4% were other subgenotypes or genotypes, 4.3% were discordant and 15.2% were unamplifiable. Surprisingly, HDV genotype 3 (HDV-3) was found in all of the HBV/HDV-infected patients that could be genotyped for HDV, confirming that HDV-3 can associate with non-F HBV genotypes. However, a HDV-3 mutant was found in 29.3% of patients and was more frequently associated with non-F HBV genotypes (P < 0.001) than were nonmutant strains, suggesting that the mutation may facilitate association of HDV-3 with non-F HBV genotypes.

  14. New molecular identifiers for Simulium limbatum and Simulium incrustatum s.l. and the detection of genetic substructure with potential implications for onchocerciasis epidemiology in the Amazonia focus of Brazil.

    PubMed

    Conceição, Priscila A; Crainey, James L; Almeida, Tatiana P; Shelley, Anthony J; Luz, Sergio L B

    2013-08-01

    The Amazonia onchocerciasis focus of southern Venezuela and northern Brazil is the larger of the two remaining Latin American onchocerciasis foci where disease transmission still occurs and is often regarded as the most challenging of all the Latin American foci to eliminate onchocerciasis. The site is home to a population of over 20,000 semi-nomadic, hunter-gatherer Yanomami people and is made-up of a mosaic of rainforest and savannah ecologies, which are influenced by the area's undulating terrain and rich geological diversity. At least six blackfly vectors have been implicated in onchocerciasis transmission in this focus; however, because of the difficulty in their routine identification the relative importance of each has been obscured. Simulium limbatum and Simulium incrustatum s.l. have both been recorded as vectors in the Amazonia focus, but they are difficult to discriminate morphologically and thus the ecological range of these species, and indeed the presence of S. limbatum in the Amazonia focus at all, have remained controversial. In the work described here, we report 15 S. incrustatum s.l. CO1 sequences and 27 S. limbatum sequences obtained from field-caught adult female blackflies collected from forest and savannah localities, inside and just outside the Amazonia focus. Phylogenetic analysis with the sequences generated in this study, showed that both the S. limbatum and the S. incrustatum s.l. CO1 sequences obtained (even from specimens living in sympatry) all fell into discrete species-specific bootstrap-supported monophyletic groups and thus confirmed the utility of the CO1 gene for identifying both these species inside the Amazonia focus. As the S. limbatum-exclusive cluster included CO1 sequences obtained from forest-caught and morphologically identified specimens these results provide the clearest evidence yet of the presence of S. limbatum inside the Amazonia focus. The question, however, of whether S. limbatum is actually a vector in the focus

  15. From Amazonia to the Atlantic forest: molecular phylogeny of Phyzelaphryninae frogs reveals unexpected diversity and a striking biogeographic pattern emphasizing conservation challenges.

    PubMed

    Fouquet, Antoine; Loebmann, Daniel; Castroviejo-Fisher, Santiago; Padial, José M; Orrico, Victor G D; Lyra, Mariana L; Roberto, Igor Joventino; Kok, Philippe J R; Haddad, Célio F B; Rodrigues, Miguel T

    2012-11-01

    Documenting the Neotropical amphibian diversity has become a major challenge facing the threat of global climate change and the pace of environmental alteration. Recent molecular phylogenetic studies have revealed that the actual number of species in South American tropical forests is largely underestimated, but also that many lineages are millions of years old. The genera Phyzelaphryne (1 sp.) and Adelophryne (6 spp.), which compose the subfamily Phyzelaphryninae, include poorly documented, secretive, and minute frogs with an unusual distribution pattern that encompasses the biotic disjunction between Amazonia and the Atlantic forest. We generated >5.8 kb sequence data from six markers for all seven nominal species of the subfamily as well as for newly discovered populations in order to (1) test the monophyly of Phyzelaphryninae, Adelophryne and Phyzelaphryne, (2) estimate species diversity within the subfamily, and (3) investigate their historical biogeography and diversification. Phylogenetic reconstruction confirmed the monophyly of each group and revealed deep subdivisions within Adelophryne and Phyzelaphryne, with three major clades in Adelophryne located in northern Amazonia, northern Atlantic forest and southern Atlantic forest. Our results suggest that the actual number of species in Phyzelaphryninae is, at least, twice the currently recognized species diversity, with almost every geographically isolated population representing an anciently divergent candidate species. Such results highlight the challenges for conservation, especially in the northern Atlantic forest where it is still degraded at a fast pace. Molecular dating revealed that Phyzelaphryninae originated in Amazonia and dispersed during early Miocene to the Atlantic forest. The two Atlantic forest clades of Adelophryne started to diversify some 7 Ma minimum, while the northern Amazonian Adelophryne diversified much earlier, some 13 Ma minimum. This striking biogeographic pattern coincides with

  16. Optical and geometrical properties of cirrus clouds in Amazonia derived from 1 year of ground-based lidar measurements

    NASA Astrophysics Data System (ADS)

    Gouveia, Diego A.; Barja, Boris; Barbosa, Henrique M. J.; Seifert, Patric; Baars, Holger; Pauliquevis, Theotonio; Artaxo, Paulo

    2017-03-01

    Cirrus clouds cover a large fraction of tropical latitudes and play an important role in Earth's radiation budget. Their optical properties, altitude, vertical and horizontal coverage control their radiative forcing, and hence detailed cirrus measurements at different geographical locations are of utmost importance. Studies reporting cirrus properties over tropical rain forests like the Amazon, however, are scarce. Studies with satellite profilers do not give information on the diurnal cycle, and the satellite imagers do not report on the cloud vertical structure. At the same time, ground-based lidar studies are restricted to a few case studies. In this paper, we derive the first comprehensive statistics of optical and geometrical properties of upper-tropospheric cirrus clouds in Amazonia. We used 1 year (July 2011 to June 2012) of ground-based lidar atmospheric observations north of Manaus, Brazil. This dataset was processed by an automatic cloud detection and optical properties retrieval algorithm. Upper-tropospheric cirrus clouds were observed more frequently than reported previously for tropical regions. The frequency of occurrence was found to be as high as 88 % during the wet season and not lower than 50 % during the dry season. The diurnal cycle shows a minimum around local noon and maximum during late afternoon, associated with the diurnal cycle of precipitation. The mean values of cirrus cloud top and base heights, cloud thickness, and cloud optical depth were 14.3 ± 1.9 (SD) km, 12.9 ± 2.2 km, 1.4 ± 1.1 km, and 0.25 ± 0.46, respectively. Cirrus clouds were found at temperatures down to -90 °C. Frequently cirrus were observed within the tropical tropopause layer (TTL), which are likely associated to slow mesoscale uplifting or to the remnants of overshooting convection. The vertical distribution was not uniform, and thin and subvisible cirrus occurred more frequently closer to the tropopause. The mean lidar ratio was 23.3 ± 8.0 sr. However, for

  17. Combined effects of deforestation and doubled atmospheric CO{sub 2} concentrations on the climate of Amazonia

    SciTech Connect

    Costa, M.H.; Foley, J.A.

    2000-01-01

    It is generally expected that the Amazon basin will experience at least two major environmental changes during the next few decades and centuries: (1) increasing areas of forest will be converted to pasture and cropland, and (2) concentrations of atmospheric CO{sub 2} will continue to rise. In this study, the authors use the National Center for Atmospheric Research GENESIS atmospheric general circulation model, coupled to the Integrated Biosphere Simulator, to determine the combined effects of large-scale deforestation and increased CO{sub 2} concentrations (including both physiological and radiative effects) on Amazonian climate. In these simulations, deforestation decreases basin-average precipitation by 0.73 mm day{sup {minus}1} over the basin, as a consequence of the general reduction in vertical motion above the deforested area (although there are some small regions with increased vertical motion). The overall effect of doubled CO{sub 2} concentrations in Amazonia is an increase in basin-average precipitation of 0.28 mm day{sup {minus}1}. The combined effect of deforestation and doubled CO{sub 2}, including the interactions among the processes, is a decrease in the basin-average precipitation of 0.42 mm day{sup {minus}1}. While the effects of deforestation and increasing CO{sub 2} concentrations on precipitation tend to counteract one another, both processes work to warm the Amazon basin. The effect of deforestation and increasing CO{sub 2} concentrations both tent to increase surface temperature, mainly because of decreases in evapotranspiration and the radiative effect of CO{sub 2}. The combined effect of deforestation and doubled CO{sub 2}, including the interactions among the processes, increases the basin-average temperature by roughly 3.5 C.

  18. High diversity of tropical peatland ecosystem types in the Pastaza-Marañón basin, Peruvian Amazonia

    NASA Astrophysics Data System (ADS)

    LäHteenoja, Outi; Page, Susan

    2011-06-01

    Very little information exists on Amazonian peatlands with most studies on tropical peatlands concentrating on Southeast Asia. Here we describe diversity of Amazonian peatland ecosystems and consider its implications for the global diversity of tropical peatland ecosystems. Nine study sites were selected from within the most extensive wetland area of Peruvian Amazonia: the 120,000 km2 Pastaza-Marañón basin. Peat thickness was determined every 500 m from the edge toward the center of each site, and peat samples were collected from two cores per site. Samples from the entire central core and surface samples from the other core were analyzed for nutrient content. Topography of four peat deposits was measured. In order to study differences in vegetation, pixel values were extracted from a satellite image. The surface peat nutrient content of the peatlands varied from very nutrient-rich to nutrient-poor. Two of the peatlands measured for their topography were domed (5.4 and 5.8 m above the stream), one was gently sloping (1.4 m above the stream), and one was flat and occurred behind a 7 m high levee. Five different peatland vegetation types were detected on the basis of pixel values derived from the satellite image. The peat cores had considerable variation in nutrient content and showed different developmental pathways. In summary, the Pastaza-Marañón basin harbors a considerable diversity of previously undescribed peatland ecosystems, representing a gradient from atmosphere-influenced, nutrient-poor ombrotrophic bogs through to river-influenced, nutrient-rich swamps. Their existence affects the habitat diversity, carbon dynamics, and hydrology of the Amazonian lowlands, and they also provide an undisturbed analog for the heavily disturbed peatlands of Southeast Asia. Considering the factors threatening the Amazonian lowlands, there is an urgent need to investigate and conserve these peatland ecosystems, which may in the near future be among the very few

  19. Genetic structure of red-handed howler monkey populations in the fragmented landscape of Eastern Brazilian Amazonia

    PubMed Central

    2010-01-01

    We genotyped 15 microsatellite loci in order to evaluate the effects of habitat fragmentation, caused by flooding of the Tucuruí reservoir, on the genetic structure of Alouatta belzebul in eastern Amazonia. The analysis included two populations sampled in 1984, representing both margins of the Tocantins river, and three populations sampled 18 years later. Minimal differences in the diversity levels between present-day (Ho = 0.62-0.69 and AR = 6.07-7.21) and pre-flooding (Ho = 0.60-0.62 and A R = 6.27-6.77) populations indicated there was no significant loss of genetic variability, possibly because of successful management strategies applied during the flooding. The changes observed were limited to shifts in the composition of alleles, which presumably reflect the admixture of subpopulations during flooding. Given this, there were significant differences in the Rst values (p = 0.05) in all but one between-site comparison. Both present-day and original populations showed a deficit of heterozygotes, which suggests that this may be typical of the species, at least at a local level, perhaps because of specific ecological characteristics. The relatively large number of private alleles recorded in all populations may be a consequence of the Wahlund effect resulting from population admixture or a process of expansion rather than the loss of rare alleles through genetic drift. Additionally, the levels of genetic variability observed in this study were higher than those reported for other species of Neotropical primates, suggesting good fitness levels in these A. belzebul populations. Regular genetic monitoring of remnant populations, especially on islands, should nevertheless be an integral component of long-term management strategies. PMID:21637590

  20. Genetic structure of red-handed howler monkey populations in the fragmented landscape of Eastern Brazilian Amazonia.

    PubMed

    Bastos, Heitor B; Gonçalves, Evonnildo C; Ferrari, Stephen F; Silva, Artur; Schneider, Maria Paula C

    2010-10-01

    We genotyped 15 microsatellite loci in order to evaluate the effects of habitat fragmentation, caused by flooding of the Tucuruí reservoir, on the genetic structure of Alouatta belzebul in eastern Amazonia. The analysis included two populations sampled in 1984, representing both margins of the Tocantins river, and three populations sampled 18 years later. Minimal differences in the diversity levels between present-day (Ho = 0.62-0.69 and A(R) = 6.07-7.21) and pre-flooding (Ho = 0.60-0.62 and A (R) = 6.27-6.77) populations indicated there was no significant loss of genetic variability, possibly because of successful management strategies applied during the flooding. The changes observed were limited to shifts in the composition of alleles, which presumably reflect the admixture of subpopulations during flooding. Given this, there were significant differences in the Rst values (p = 0.05) in all but one between-site comparison. Both present-day and original populations showed a deficit of heterozygotes, which suggests that this may be typical of the species, at least at a local level, perhaps because of specific ecological characteristics. The relatively large number of private alleles recorded in all populations may be a consequence of the Wahlund effect resulting from population admixture or a process of expansion rather than the loss of rare alleles through genetic drift. Additionally, the levels of genetic variability observed in this study were higher than those reported for other species of Neotropical primates, suggesting good fitness levels in these A. belzebul populations. Regular genetic monitoring of remnant populations, especially on islands, should nevertheless be an integral component of long-term management strategies.

  1. Who Cares about Forests and Why? Individual Values Attributed to Forests in a Post-Frontier Region in Amazonia

    PubMed Central

    Morsello, Carla; Parry, Luke; Pardini, Renata

    2016-01-01

    Understanding the multiple ways people value forests is important, as individual values regarding nature have been shown to partly determine willingness to participate in conservation initiatives. As individual values are influenced by past experiences, the way people value forests may be related to the ecosystem services they use and receive. We here aim to investigate if people value forests because of material and non-material benefits forest provide (material and non-material values), and if these values are defined by previous experiences associated with using forest resources and having frequent contact with forests. By interviewing 363 residents across 20 landscapes varying in forest cover in a post-frontier region in Amazonia, we evaluated: (1) if the use of forest resources—especially bushmeat, important for sustenance and cash income in virtually all tropical forests—is associated with attributing higher material value to forests; (2) whether the contact with forest (estimated by local forest cover and visits to forests) is associated with attributing higher non-material value to forests. As expected, respondents from households where hunting occurs and bushmeat consumption is more frequent attributed higher material value to forests, and those living in more deforested landscapes and that visited forests less often attributed lower non-material value to forests. The importance of bushmeat in shaping the way people value forests suggests that encouraging the sustainable use of this product will encourage forest conservation. Results also point to a potential dangerous reinforcing cycle: low forest cover and the loss of contact with forests may erode forest values and facilitate further deforestation. Engaging rural communities in forest conservation initiatives is challenging yet urgent in degraded landscapes, although harnessing appreciation for bushmeat could offer a starting point. PMID:27942038

  2. Substances, relationships and the omnipresence of the body: an overview of Ashéninka ethnomedicine (Western Amazonia)

    PubMed Central

    Lenaerts, Marc

    2006-01-01

    Indigenous Amazonian ethnomedicine usually relies on numerous forms of healing, exercised by both specialists and non-specialists. Such is the case among the "Asheninka del Ucayali" (Arawak from the Peru-Brazil border). This paper attempts to elicit the underlying consistencies of their manifold, often contradictory practices and statements. It draws on ethnographic data gathered between 1997 and 2000, and is essentially based on my own interviews and participant observation. Concerning some specific points these data are also compared with ethnobotanical findings, to highlight significant peculiarities of the Asheninka approach. The first question is about the nature of a "good medicine". When the Asheninka borrow botanical knowledge from another ethnic group and comment the fact, the contrast between indigenous self-assessments and objective ethnobotanical measurements points out a crucial difference: While the Western approach focuses essentially on chemical effectiveness of the plants themselves, Asheninka people pay much more attention to relational aspects. The relational dimension also involves the plants themselves, as a sort of person. The point has implications in Asheninka shamanism and herbalism. A shaman does not necessarily need to be a good botanist. His main concern is managing a network of personal relationships involving all kinds of living beings. This network is supposed to be the mainspring of illness – a belief shared by both shamans and ordinary people. However, most ordinary people have detailed herbal knowledge. In fact, this everyday herbalism amounts to an alternative explanatory model. Such a coexistence of two contrasting explanatory systems is frequent in Amazonia. Among the Asheninka, nevertheless, the underlying hierarchy is clear: the herbal, apparently more materialistic, approach is embedded in the shamanic, plainly relational, model. PMID:17096839

  3. Landscape dynamics in northwestern Amazonia: an assessment of pastures, fire and illicit crops as drivers of tropical deforestation.

    PubMed

    Armenteras, Dolors; Rodríguez, Nelly; Retana, Javier

    2013-01-01

    Many studies have identified drivers of deforestation throughout the tropics and, in most cases, have recognised differences in the level of threat. However, only a few have also looked at the temporal and spatial dynamics by which those drivers act, which is critical for assessing the conservation of biodiversity as well as for landscape planning. In this study, we analyse land cover change between 2000 and 2009 in north-western Colombian Amazonia to identify the interactions between the use of fire, cultivation of illicit crops and establishment of pastures, and their impacts on the loss of forest in the region. Yearly analyses were undertaken at randomly selected sample areas to quantify the average areas of transition of land cover types under different landscape compositions: forest-dominated mosaics, pasture mosaics, fire mosaics, and illicit crop mosaics. Our results indicate that despite the fact that forest areas were well-preserved, deforestation occurred at a low annual rate (0.06%). Conversion to pasture was the main factor responsible for forest loss (the area of pastures tripled within forest mosaics over 8 years), and this process was independent of the landscape matrix in which the forests were located. In fire mosaics, burning is a common tool for forest clearing and conversion to pasture. Thus, forests in fire mosaics were highly disturbed and frequently transformed from primary to secondary forests. The use of fire for illicit cropping was not detected, partly due to the small size of common illicit crops. Forest regeneration from pastures and secondary vegetation was observed in areas with large amounts of natural forest. Overall, assuming the continuation of the observed pasture conversion trend and the use of forest fire, we suggest that our results should be incorporated into a spatially explicit and integrated decision support tool to target and focus land-planning activities and policies.

  4. Who Cares about Forests and Why? Individual Values Attributed to Forests in a Post-Frontier Region in Amazonia.

    PubMed

    Carignano Torres, Patricia; Morsello, Carla; Parry, Luke; Pardini, Renata

    2016-01-01

    Understanding the multiple ways people value forests is important, as individual values regarding nature have been shown to partly determine willingness to participate in conservation initiatives. As individual values are influenced by past experiences, the way people value forests may be related to the ecosystem services they use and receive. We here aim to investigate if people value forests because of material and non-material benefits forest provide (material and non-material values), and if these values are defined by previous experiences associated with using forest resources and having frequent contact with forests. By interviewing 363 residents across 20 landscapes varying in forest cover in a post-frontier region in Amazonia, we evaluated: (1) if the use of forest resources-especially bushmeat, important for sustenance and cash income in virtually all tropical forests-is associated with attributing higher material value to forests; (2) whether the contact with forest (estimated by local forest cover and visits to forests) is associated with attributing higher non-material value to forests. As expected, respondents from households where hunting occurs and bushmeat consumption is more frequent attributed higher material value to forests, and those living in more deforested landscapes and that visited forests less often attributed lower non-material value to forests. The importance of bushmeat in shaping the way people value forests suggests that encouraging the sustainable use of this product will encourage forest conservation. Results also point to a potential dangerous reinforcing cycle: low forest cover and the loss of contact with forests may erode forest values and facilitate further deforestation. Engaging rural communities in forest conservation initiatives is challenging yet urgent in degraded landscapes, although harnessing appreciation for bushmeat could offer a starting point.

  5. Vegetation changes and human impact inferred from an oxbow lake in southwestern Amazonia, Brazil since the 19th century

    NASA Astrophysics Data System (ADS)

    Rodríguez-Zorro, Paula A.; Enters, Dirk; Hermanowski, Barbara; da Costa, Marcondes Lima; Behling, Hermann

    2015-10-01

    Pollen and X-ray fluorescence spectrometry (XRF) analyses from a 272 cm-long sediment core of Lago Amapá, an oxbow lake in western Amazonia, reveal the first palaeoecological investigation of late Holocene sediments in Acre state, Brazil. Radiocarbon dating of older sediments failed due to re-deposition of organic material but a historical map suggests that lacustrine deposition started at 1900 AD. We detected two periods of changes in sediment and vegetation, dominated by pioneer taxa especially Cecropia. The first period around 1900 AD is documenting an initial oxbow lake, with regular fluvial input (high Ti) and low accumulation of organic matter (low inc/coh ratio). During that period Andean pollen taxa originating from Peruvian Andean headwaters were deposited. A fully lacustrine phase started about 1950 AD and is characterized by prolonged periods of stagnant water (low Fe/Mn ratio). The increase of pioneer taxa, sedimentation rates and a reduction of most of the XRF element counts point to a period during which Lago Amapá was a more isolated lake which was flooded only during exceptional severe flood events and is catching mainly anthropogenic disturbances. The extensive human influence during this period was assumed by 1) the high occurrence of pioneer taxa and the absence of charcoal which could indicate changes in vegetation possibly as a result of logging, 2) the Ca and Ti/K ratio which reflect changes to a local sediment source, and 3) comparison of Landsat images from the last 30 years which shows broad changes in vegetation cover and land transformation in the peripheral areas of the oxbow lake.

  6. Influence of landscape heterogeneity on spatial patterns of wood productivity, wood specific density and above ground biomass in Amazonia

    NASA Astrophysics Data System (ADS)

    Anderson, L. O.; Malhi, Y.; Ladle, R. J.; Aragão, L. E. O. C.; Shimabukuro, Y.; Phillips, O. L.; Baker, T.; Costa, A. C. L.; Espejo, J. S.; Higuchi, N.; Laurance, W. F.; López-González, G.; Monteagudo, A.; Núñez-Vargas, P.; Peacock, J.; Quesada, C. A.; Almeida, S.

    2009-09-01

    Long-term studies using the RAINFOR network of forest plots have generated significant insights into the spatial and temporal dynamics of forest carbon cycling in Amazonia. In this work, we map and explore the landscape context of several major RAINFOR plot clusters using Landsat ETM+ satellite data. In particular, we explore how representative the plots are of their landscape context, and test whether bias in plot location within landscapes may be influencing the regional mean values obtained for important forest biophysical parameters. Specifically, we evaluate whether the regional variations in wood productivity, wood specific density and above ground biomass derived from the RAINFOR network could be driven by systematic and unintentional biases in plot location. Remote sensing data covering 45 field plots were aggregated to generate landscape maps to identify the specific physiognomy of the plots. In the Landsat ETM+ data, it was possible to spectrally differentiate three types of terra firme forest, three types of forests over Paleovarzea geomorphologycal formation, two types of bamboo-dominated forest, palm forest, Heliconia monodominant vegetation, swamp forest, disturbed forests and land use areas. Overall, the plots were generally representative of the forest physiognomies in the landscape in which they are located. Furthermore, the analysis supports the observed regional trends in those important forest parameters. This study demonstrates the utility of landscape scale analysis of forest physiognomies for validating and supporting the finds of plot based studies. Moreover, the more precise geolocation of many key RAINFOR plot clusters achieved during this research provides important contextual information for studies employing the RAINFOR database.

  7. Landscape Dynamics in Northwestern Amazonia: An Assessment of Pastures, Fire and Illicit Crops as Drivers of Tropical Deforestation

    PubMed Central

    Armenteras, Dolors; Rodríguez, Nelly; Retana, Javier

    2013-01-01

    Many studies have identified drivers of deforestation throughout the tropics and, in most cases, have recognised differences in the level of threat. However, only a few have also looked at the temporal and spatial dynamics by which those drivers act, which is critical for assessing the conservation of biodiversity as well as for landscape planning. In this study, we analyse land cover change between 2000 and 2009 in north-western Colombian Amazonia to identify the interactions between the use of fire, cultivation of illicit crops and establishment of pastures, and their impacts on the loss of forest in the region. Yearly analyses were undertaken at randomly selected sample areas to quantify the average areas of transition of land cover types under different landscape compositions: forest-dominated mosaics, pasture mosaics, fire mosaics, and illicit crop mosaics. Our results indicate that despite the fact that forest areas were well-preserved, deforestation occurred at a low annual rate (0.06%). Conversion to pasture was the main factor responsible for forest loss (the area of pastures tripled within forest mosaics over 8 years), and this process was independent of the landscape matrix in which the forests were located. In fire mosaics, burning is a common tool for forest clearing and conversion to pasture. Thus, forests in fire mosaics were highly disturbed and frequently transformed from primary to secondary forests. The use of fire for illicit cropping was not detected, partly due to the small size of common illicit crops. Forest regeneration from pastures and secondary vegetation was observed in areas with large amounts of natural forest. Overall, assuming the continuation of the observed pasture conversion trend and the use of forest fire, we suggest that our results should be incorporated into a spatially explicit and integrated decision support tool to target and focus land-planning activities and policies. PMID:23382890

  8. Influence of landscape heterogeneity on spatial patterns of wood productivity, wood specific density and above ground biomass in Amazonia

    NASA Astrophysics Data System (ADS)

    Anderson, L. O.; Malhi, Y.; Ladle, R. J.; Aragão, L. E. O. C.; Shimabukuro, Y.; Phillips, O. L.; Baker, T.; Costa, A. C. L.; Espejo, J. S.; Higuchi, N.; Laurance, W. F.; López-González, G.; Monteagudo, A.; Núñez-Vargas, P.; Peacock, J.; Quesada, C. A.; Almeida, S.; Vásquez, R.

    2009-02-01

    Long-term studies using the RAINFOR network of forest plots have generated significant insights into the spatial and temporal dynamics of forest carbon cycling in Amazonia. In this work, we map and explore the landscape context of several major RAINFOR plot clusters using Landsat ETM+ satellite data. In particular, we explore how representative the plots are of their landscape context, and test whether bias in plot location within landscapes may be influencing the regional mean values obtained for important forest biophysical parameters. Specifically, we evaluate whether the regional variations in wood productivity, wood specific density and above ground biomass derived from the RAINFOR network could be driven by systematic and unintentional biases in plot location. Remote sensing data covering 45 field plots were aggregated to generate landscape maps to identify the specific physiognomy of the plots. In the Landsat ETM+ data, it was possible to spectrally differentiate three types of terra firme forest, three types of alluvial terrain forest, two types of bamboo-dominated forest, palm forest, Heliconia monodominant vegetation, swamp forest, disturbed forests and land use areas. Overall, the plots were generally representative of the forest physiognomies in the landscape in which they are located. Furthermore, the analysis supports the observed regional trends in those important forest parameters. This study demonstrates the utility of landscape scale analysis of forest physiognomies for validating and supporting the finds of plot based studies. Moreover, the more precise geolocation of many key RAINFOR plot clusters achieved during this research provides important contextual information for studies employing the RAINFOR database.

  9. Activity budget, diet, and use of space by two groups of squirrel monkeys (Saimiri sciureus) in eastern Amazonia.

    PubMed

    Pinheiro, Tatyana; Ferrari, Stephen F; Lopes, Maria Aparecida

    2013-07-01

    Squirrel monkeys (Saimiri spp.) are widely distributed in the Amazon basin. This study describes the ecological and behavioral patterns of two social groups of S. sciureus in forests adjacent to the Tucuruí hydroelectric reservoir in eastern Amazonia, including range size, activity budgets, and composition of the diet. The groups were monitored at Base 4 (group B4) and Germoplasma Island (group GI). Quantitative behavioral data were collected using instantaneous scan sampling to record behavior, substrate use, and height. Home ranges were delimited using a GPS to determine group position after each 50 m of movement. Home ranges were 75.0 ha for group B4 (39 members) and 77.5 ha for group GI (32 members). The use of vertical strata was well defined, with a marked preference for the middle and lower levels of the canopy. The activity budgets of both groups were typical of those of other squirrel monkeys and were dominated by foraging (B4 = 48.7 %; GI = 49.6 %), moving (both groups 28.9 %), and feeding (B4 = 14.6 %; GI = 12.4 %). Resting was rare (B4 = 3.5 %; GI = 2.6 %) and less common than social behavior (B4 = 4.3 %; GI = 6.4 %). The diet of both groups was dominated by plant material (B4 = 70.7 % of feeding records; GI = 71.4 %), which is in contrast with the more insectivorous diets recorded for Saimiri at other sites. Group GI spent more time foraging during the dry season, whereas group B4 spent more time in the rainy season when the consumption of fruit increased (significantly, in the case of group GI). The less insectivorous diet of these groups may be due to a number of factors, including the unique habitat configuration at the site and reduced hydrological stress due to the proximity of the reservoir.

  10. Chemical characterisation of total suspended particulate matter from a remote area in Amazonia

    NASA Astrophysics Data System (ADS)

    Gonçalves, Cátia; Figueiredo, Bernardino R.; Alves, Célia A.; Cardoso, Arnaldo A.; da Silva, Rodrigo; Kanzawa, Simone H.; Vicente, Ana Margarida

    2016-12-01

    This research had as study object the total suspended particulate matter collected in the Alenquer region, a remote area in the Pará state. The main objectives were the characterisation of the inorganic and organic chemical composition of the aerosol, looking for seasonal patterns and the identification of probable emission sources and formation processes. A set of 30 samples were collected in the rainy (April-May) and dry season (August-September) of 2014. The analytical methods included gravimetric analysis, water-soluble ions analysis by ion chromatography (IC), elemental analysis by inductively coupled plasma mass spectrometry (ICP-MS) equipped with collision cell technology, carbonaceous content determination with a thermal-optical system and organic speciation by gas chromatography-mass spectrometry (GC-MS). The average concentrations of particulate matter ranged from 14 ± 1.3 μg·m- 3 to 31 ± 7.8 μg·m- 3, in the rainy and dry season, respectively. The carbonaceous content represented, on average, approximately 27% and 21% of the particulate matter in the rainy and dry season, respectively. Na+, Cl-, SO₄2 -, and NO₃- yield the highest concentrations in both seasons. Na was the dominant element, reflecting the transport of air masses from the Atlantic. An increase in concentrations between the rainy and dry seasons was especially noted for the terrigenous elements such Mn, Fe and Al. The chromatographically resolved organics included n-alkanes, n-alkenes, PAHs, n-alkanoic acids, n-di-acids, resin acids and some phenolic compounds. The primary inputs of organic constituents to the aerosols of Alenquer based on the homologous compound series and biomarkers were: (i) natural emissions from terrestrial higher plants waxes, particularly in dry season; (ii) anthropogenic emissions from diesel fuel combustion and biomass combustion, predominating during the dry season. The chemical characterisation along with the backward trajectory cluster analysis

  11. Distribution of throughfall and stemflow in multi-strata agroforestry, perennial monoculture, fallow and primary forest in central Amazonia, Brazil

    NASA Astrophysics Data System (ADS)

    Schroth, Götz; Ferreira da Silva, Luciana; Wolf, Marc-Andree; Geraldes Teixeira, Wenceslau; Zech, Wolfgang

    1999-07-01

    The partitioning of rain water into throughfall, stemflow and interception loss when passing through plant canopies depends on properties of the respective plant species, such as leaf area and branch angles. In heterogeneous vegetation, such as tropical forest or polycultural systems, the presence of different plant species may consequently result in a mosaic of situations with respect to quantity and quality of water inputs into the soil. As these processes influence not only the water availability for the plants, but also water infiltration and nutrient leaching, the understanding of plant effects on the repartitioning of rain water may help in the optimization of land use systems and management practices. We measured throughfall and stemflow in a perennial polyculture (multi-strata agroforestry), monocultures of peach palm (Bactris gasipaes) for fruit and for palmito, a monoculture of cupuaçu (Theobroma grandiflorum), spontaneous fallow and primary forest during one year in central Amazonia, Brazil. The effect on rain water partitioning was measured separately for four useful tree species in the polyculture and for two tree species in the primary forest. Throughfall at two stem distances, and stemflow, differed significantly between tree species, resulting in pronounced spatial patterns of water input into the soil in the polyculture system. For two tree species, peach palm for fruit (Bactris gasipaes) and Brazil nut trees (Bertholletia excelsa), the water input into the soil near the stem was significantly higher than the open-area rainfall. This could lead to increased nutrient leaching when fertilizer is applied close to the stem of these trees. In the primary forest, such spatial patterns could also be detected, with significantly higher water input near a palm (Oenocarpus bacaba) than near a dicotyledonous tree species (Eschweilera sp.). Interception losses were 6·4% in the polyculture, 13·9 and 12·3% in the peach palm monocultures for fruit and for

  12. A minute ostracod (Crustacea: Cytheromatidae) from the Miocene Solimões Formation (western Amazonia, Brazil): evidence for marine incursions?

    PubMed Central

    Gross, Martin; Ramos, Maria Ines F.; Piller, Werner E.

    2016-01-01

    A huge wetland (the ‘Pebas system’) covered western Amazonia during the Miocene, hosting a highly diverse and endemic aquatic fauna. One of the most contentious issues concerns the existence, potential pathways and effects of marine incursions on this ecosystem. Palaeontological evidences (body fossils) are rare. The finding of a new, presumably marine ostracod species (Pellucistoma curupira sp. nov.) in the upper middle Miocene Solimões Formation initiated a taxonomic, ecological and biogeographical review of the genus Pellucistoma. We demonstrate that this marine (sublittoral, euhaline), subtropical–tropical taxon is biogeographically confined to the Americas. The biogeographical distribution of Pellucistoma largely depends on geographical, thermal and osmotic barriers (e.g. land bridges, deep and/or cold waters, sea currents, salinity). We assume an Oligocene/early Miocene, Caribbean origin for Pellucistoma and outline the dispersal of hitherto known species up to the Holocene. Pellucistoma curupira sp. nov. is dwarfed in comparison to all other species of this genus and extremely thin-shelled. This is probably related to poorly oxygenated waters and, in particular, to strongly reduced salinity. The associated ostracod fauna (dominated by the eurypotent Cyprideis and a few, also stunted ostracods of possibly marine ancestry) supports this claim. Geochemical analyses (δ18O, δ13C) on co-occurring ostracod valves (Cyprideis spp.) yielded very light values, indicative of a freshwater setting. These observations point to a successful adaptation of P. curupira sp. nov. to freshwater conditions and therefore do not signify the presence of marine water. Pellucistoma curupira sp. nov. shows closest affinities to Caribbean species. We hypothesize that Pellucistoma reached northern South America (Llanos Basin) during marine incursions in the early Miocene. While larger animals of marine origin (e.g. fishes, dolphins, manatees) migrated actively into the Pebas

  13. a New Site at Central Amazonia Dedicated to Long Term Cloud Properties Observations - Description, First Results and Future Perspectives.

    NASA Astrophysics Data System (ADS)

    Pauliquevis, T.; Barbosa, H. M.; Adams, D. K.; Artaxo, P.; Cirino, G. G.; Barja Gonzalez, B.; Correia, A. L.; Gomes, H. B.; Gouveia, D. A.; Padua, M. B.; Rosario, N. M. E. D.; Souza, R. A. F. D.; Nascimento dos Santos, R. M.; Sapucci, L.; Portela, B. T.

    2014-12-01

    Amazon basin during the wet season is one of the few places on Earth where "natural atmosphere", as it is expected to be in pre-industrial era, can be observed. Atmosphere in clean Amazonia can be regarded as a baseline state of tropical atmosphere. Its hydrological cycle is extreme active, as well as its convection. Several scientific questions with respect to convection remain unclear. Diurnal cycle of convection is far from adequately represented in numeric models. Precipitation typically occurs in models in the first few hours in the morning, whereas actual rain occurs mostly in the early afternoon. Convection parameterizations lack the ability to represent it adequately due to the models coarse resolution of parameterizations compared to the spatial scale of shallow convection. An adequate comprehension of shallow to deep convection transition is critical to improve convection representation in models. To reach this goal, long term measurements that could characterize clouds and convection diurnal cycle are fundamental. The implementation of ACONVEX (Atmospheric CONVection EXperiment) site, situated 50 km upwind from the megacity of Manaus ( -2.894263S°, -59.971452W) aims to fill the existent gap in long term measurements. It is designed to make measurements for more than 10 yrs, and characterize cloud properties in a climatological perspective. The site started its operation in August, 2011, initially with the Raman Lidar. Present time instrumentation set comprises: 1) UV Lidar Raman, 2) CIMEL Sunphotometer, 3) MultiFilter shadow band Radiometer (MFR), 4) GNSS/GPS Receiver, 5) Vertical Pointing Radar, 6) Disdrometer, 7) Ceilometer, 8) Met station. Two sky imagers and a microwave radiometer are about to be operated and will be able to derive 1) Cloud Cover, 2) Cloud Top and Cloud Base Heights, 3) Liquid Water Content, 4) Integrated Precipitable Water, 5) PBL Height, 6) Rain Rate (vertical profile and at surface). In this poster we discuss the site in more

  14. From forest to cropland and pasture systems: a critical review of soil organic carbon stocks changes in Amazonia.

    PubMed

    Fujisaki, Kenji; Perrin, Anne-Sophie; Desjardins, Thierry; Bernoux, Martial; Balbino, Luiz Carlos; Brossard, Michel

    2015-02-26

    The impact of deforestation on soil organic carbon (SOC) stocks is important in the context of climate change and agricultural soil use. Trends of SOC stock changes after agroecosystem establishment vary according to the spatial scale considered, and factors explaining these trends may differ sometimes according to meta-analyses. We have reviewed the knowledge about changes in SOC stocks in Amazonia after the establishment of pasture or cropland, sought relationships between observed changes and soil, climatic variables and management practices, and synthesized the δ(13) C measured in pastures. Our dataset consisted of 21 studies mostly synchronic, across 52 sites (Brazil, Colombia, French Guiana, Suriname), totalling 70 forest-agroecosystem comparisons. We found that pastures (n = 52, mean age = 17.6 years) had slightly higher SOC stocks than forest (+6.8 ± 3.1 %), whereas croplands (n = 18, mean age = 8.7 years) had lower SOC stocks than forest (-8.5 ± 2.9 %). Annual precipitation and SOC stocks under forest had no effect on the SOC changes in the agroecosystems. For croplands, we found a lower SOC loss than other meta-analyses, but the short time period after deforestation here could have reduced this loss. There was no clear effect of tillage on the SOC response. Management of pastures, whether they were degraded/nominal/improved, had no significant effect on SOC response. δ(13) C measurements on 16 pasture chronosequences showed that decay of forest-derived SOC was variable, whereas pasture-derived SOC was less so and was characterized by an accumulation plateau of 20 Mg SOC ha(-1) after 20 years. The large uncertainties in SOC response observed could be derived from the chronosequence approach, sensitive to natural soil variability and to human management practices. This study emphasizes the need for diachronic and long-term studies, associated with better knowledge of agroecosystem management.

  15. A minute ostracod (Crustacea: Cytheromatidae) from the Miocene Solimões Formation (western Amazonia, Brazil): evidence for marine incursions?

    PubMed

    Gross, Martin; Ramos, Maria Ines F; Piller, Werner E

    2016-07-02

    A huge wetland (the 'Pebas system') covered western Amazonia during the Miocene, hosting a highly diverse and endemic aquatic fauna. One of the most contentious issues concerns the existence, potential pathways and effects of marine incursions on this ecosystem. Palaeontological evidences (body fossils) are rare. The finding of a new, presumably marine ostracod species (Pellucistoma curupira sp. nov.) in the upper middle Miocene Solimões Formation initiated a taxonomic, ecological and biogeographical review of the genus Pellucistoma. We demonstrate that this marine (sublittoral, euhaline), subtropical-tropical taxon is biogeographically confined to the Americas. The biogeographical distribution of Pellucistoma largely depends on geographical, thermal and osmotic barriers (e.g. land bridges, deep and/or cold waters, sea currents, salinity). We assume an Oligocene/early Miocene, Caribbean origin for Pellucistoma and outline the dispersal of hitherto known species up to the Holocene. Pellucistoma curupira sp. nov. is dwarfed in comparison to all other species of this genus and extremely thin-shelled. This is probably related to poorly oxygenated waters and, in particular, to strongly reduced salinity. The associated ostracod fauna (dominated by the eurypotent Cyprideis and a few, also stunted ostracods of possibly marine ancestry) supports this claim. Geochemical analyses (δ(18)O, δ(13)C) on co-occurring ostracod valves (Cyprideis spp.) yielded very light values, indicative of a freshwater setting. These observations point to a successful adaptation of P. curupira sp. nov. to freshwater conditions and therefore do not signify the presence of marine water. Pellucistoma curupira sp. nov. shows closest affinities to Caribbean species. We hypothesize that Pellucistoma reached northern South America (Llanos Basin) during marine incursions in the early Miocene. While larger animals of marine origin (e.g. fishes, dolphins, manatees) migrated actively into the Pebas

  16. Leaf gas exchange and carbohydrates in tropical trees differing in successional status in two light environments in central Amazonia.

    PubMed

    Marenco, R A; de C Gonçalves, J F; Vieira, G

    2001-12-01

    Monoculture and mixed stands of mahogany (Swietenia macrophylla King) and tonka bean (Dipteryx odorata Willd.) trees were established on degraded land in central Amazonia to compare leaf gas exchange parameters between plants grown in sunlight in an open field and in shade beneath a balsa wood (Ochroma pyramidale Cav.) canopy. Shading increased specific leaf area by about 50% in both species. Shading reduced height and diameter growth of S. macrophylla, whereas it increased these parameters for D. odorata. Light-saturated photosynthesis (Amax), stomatal conductance (gs) and transpiration (E) were higher in S. macrophylla than in D. odorata. In S. macrophylla, Amax was higher in sun leaves (12.9 +/- 0.9 micromol m-2 s-1) than in shade leaves (10.2 +/- 1.0 micromol m-2 s-1), whereas light environment had no significant effect on Amax of D. odorata. In both species, CO2-saturated photosynthesis (Apot) was higher in sun leaves (22 +/- 1.4 micromol m-2 s-1) than in shade leaves (17-20 +/- 0.8 micromol m-2 s-1). Stomatal conductance and E increased in sun leaves of S. macrophylla by 45 and 38%, respectively, whereas light environment did not affect gs and E of D. odorata. Photorespiration rates (Pr) varied from 28 to 36% of net photosynthesis (A) at ambient atmospheric CO2 concentration (Ca) but declined to around 7% of A at higher Ca. Leaf dark respiration (Rd) and the CO2 compensation point (Gamma) were lower in shade-grown plants than in open-grown plants. Compared with shade-grown plants, total nonstructural carbohydrate (TNC) concentrations increased by 56% in S. macrophylla and by 30% in D. odorata in the open field. Leaf nitrogen (NL) concentrations were higher in open-grown plants than in shade-grown plants of both species, and TNC and NL concentrations were negatively correlated (r = -0.77). High TNC accumulation in S. macrophylla in the open field suggests that photosynthesis is unlikely to be growth-limiting at this site. We conclude that photosynthetic

  17. Influence of urban pollution on the production of organic particulate matter from isoprene epoxydiols in central Amazonia

    DOE PAGES

    de Sa, Suzane S.; Palm, Brett B.; Campuzano-Jost, Pedro; ...

    2016-12-13

    The atmospheric chemistry of isoprene contributes to the production of a substantial mass fraction of the particulate matter (PM) over tropical forests. Isoprene epoxydiols (IEPOX) produced in the gas phase by the oxidation of isoprene under HO2-dominant conditions are subsequently taken up by particles, thereby leading to production of secondary organic PM. The present study investigates possible perturbations to this pathway by urban pollution. The measurement site in central Amazonia was located 4 to 6 hours downwind of Manaus, Brazil. Measurements took place from February through March 2014 of the wet season, as part of the GoAmazon2014/5 experiment. Mass spectramore » of organic PM collected with an Aerodyne Aerosol Mass Spectrometer were analyzed by positive-matrix factorization. One resolved statistical factor (“IEPOX-SOA factor”) was associated with PM production by the IEPOX pathway. Loadings of this factor correlated with independently measured mass concentrations of tracers of IEPOX-derived PM, namely C5-alkene triols and 2-methyltetrols (R = 0.96 and 0.78, respectively). Factor loading, as well as the ratio of the factor loading to organic PM mass concentration, decreased under polluted compared to background conditions. For the study period, sulfate concentration explained 37 % of the variability in the factor loading. After segregation of the data set by NOy concentration, the sulfate concentration explained up to 75 % of the variability in factor loading within the NOy subsets. The sulfate-detrended IEPOX-SOA factor loading decreased by two- to three-fold for an increase in NOy concentration from 0.5 to 2 ppb. Here, the suppressing effects of elevated NO dominated over the enhancing effects of higher sulfate with respect to the production of IEPOX-derived PM. Relative to background conditions, the Manaus pollution contributed more significantly to NOy than to sulfate. In this light, increased emissions of nitrogen oxides, as anticipated for

  18. Influence of urban pollution on the production of organic particulate matter from isoprene epoxydiols in central Amazonia

    SciTech Connect

    de Sa, Suzane S.; Palm, Brett B.; Campuzano-Jost, Pedro; Day, Douglas A.; Newburn, Matthew K.; Hu, Weiwei; Isaacman-VanWertz, Gabriel; Yee, Lindsay D.; Thalman, Ryan; Brito, Joel; Carbone, Samara; Artaxo, Paulo; Goldstein, Allen H.; Manzi, Antonio O.; Souza, Rodrigo A. F.; Mei, Fan; Shilling, John E.; Springston, Stephen R.; Wang, Jian; Surratt, Jason D.; Alexander, M. Lizabeth; Jimenez, Jose L.; Martin, Scot T.

    2016-12-13

    The atmospheric chemistry of isoprene contributes to the production of a substantial mass fraction of the particulate matter (PM) over tropical forests. Isoprene epoxydiols (IEPOX) produced in the gas phase by the oxidation of isoprene under HO2-dominant conditions are subsequently taken up by particles, thereby leading to production of secondary organic PM. The present study investigates possible perturbations to this pathway by urban pollution. The measurement site in central Amazonia was located 4 to 6 hours downwind of Manaus, Brazil. Measurements took place from February through March 2014 of the wet season, as part of the GoAmazon2014/5 experiment. Mass spectra of organic PM collected with an Aerodyne Aerosol Mass Spectrometer were analyzed by positive-matrix factorization. One resolved statistical factor (“IEPOX-SOA factor”) was associated with PM production by the IEPOX pathway. Loadings of this factor correlated with independently measured mass concentrations of tracers of IEPOX-derived PM, namely C5-alkene triols and 2-methyltetrols (R = 0.96 and 0.78, respectively). Factor loading, as well as the ratio of the factor loading to organic PM mass concentration, decreased under polluted compared to background conditions. For the study period, sulfate concentration explained 37 % of the variability in the factor loading. After segregation of the data set by NOy concentration, the sulfate concentration explained up to 75 % of the variability in factor loading within the NOy subsets. The sulfate-detrended IEPOX-SOA factor loading decreased by two- to three-fold for an increase in NOy concentration from 0.5 to 2 ppb. Here, the suppressing effects of elevated NO dominated over the enhancing effects of higher sulfate with respect to the production of IEPOX-derived PM. Relative to background conditions, the Manaus pollution contributed more significantly to NOy than to sulfate. In this light

  19. Lacustrine Records of Forest Fire Indicators and Trace Elements Deposition in an Land Use Change Region in the Brazilian Amazonia (Alta Floresta, MT)

    NASA Astrophysics Data System (ADS)

    Rodrigues, R. R.; Conceicão, M. G.; Cordeiro, R. C.; Turcq, B. J.; Seoane, J. S.; Sifeddine, A.

    2009-05-01

    The dynamics of terrestrial ecosystems depend on interactions between the carbon cycle, nutrient cycles, and the hydrological cycle, all of which may be modified by climate and human actions. Terrestrial ecological systems, in which carbon is retained in live biomass, decomposing organic matter, and soil, play an important role in the global carbon cycle. Human activities change carbon stocks in these pools and exchanges between them and the atmosphere through land-use change and other activities. From 1850 to 1998 about 136 (+55) Gt C has been emitted as a result of land-use change, predominantly from forest ecosystems. Amazonia's carbon storage potential gives great importance to land-use changes in this region because disturbances of the natural landscape can increase atmospheric carbon and affect global biogeochemical cycles. Mercury release from gold mining activities and deforestation are the two most important environmental issues in the Amazon Basin. Gold mining activities in Amazonia have been responsible for the release of about 2000-3000 t of Hg over the last 20 y. In Alta Floresta region (southern Amazonia), concurrent with the deforestation, an intense gold rush occurred with the exploration of riverbed sediments. This region was a significant gold mining site from 1980 to 1996. This study aims to understand the atmospheric deposition rates of charcoal particles, mercury and other trace elements and discuss the environmental changes caused by man activities in an area of an intense land use change. Accordingly to the fact that in Brazilian Amazonia the colonization process generally takes place after the building of a road, an 82 cm core (AF SSW 150) was collected in a lake formed by the barrier effect of a road embankment and distant 150 km of the center of Alta Floresta city. The ages of the sedimentary sections in the core were calculated by the activity of 210Pb. The grain size profile showed a huge change from 1985, with the dominance of fine

  20. Scientific Collaboration Along the Trinational Frontier of Brazil-Bolivia-Peru: Implications for Regional Land-Use in the MAP Region of Southwestern Amazonia

    NASA Astrophysics Data System (ADS)

    Brown, I.

    2002-12-01

    High-speed road systems are connecting southwestern Amazonia (~1.5 million km2) to Pacific and Atlantic ports as well as providing greater access to Brazilian, Bolivian and Peruvian urban markets. Coupled with this increased accessibility are ambitious governmental plans to expand production of timber, non-timber forest products, and beef, all of which are likely to modify human migrations in the region. The heart of southwestern Amazonia lies in the trinational frontier region of Madre de Dios Department/Peru, eastern Acre State/Brazil and Pando Department/Bolivia (MAP region: ~200,000 km2, ~500,000 inhabitants). The MAP region composes a global hot spot of terrestrial biodiversity and has become an axis of integration for the three countries. Faced with rapid change in socioeconomic trends, regional environmental scientists and professionals have promoted collaborative projects to analyze land use trends and their forcing functions and to supply these results to local and regional societies. In addition, they have begun to develop a regional scientific community that bridges different nationalities and specialties. The projects are both international - as they involve three countries - and local/regional as they involve institutions that are within a radius of 300 km of the border. In the past two years, LBA-sponsored activities have helped bring over 100 professionals together in the region in five MAP-oriented workshops. The research results are now influencing public policy and are being incorporated into the regional school systems with the objective of maximizing the benefits and minimizing the adverse impacts of the changing socio-economic trends on land-use and development in the MAP region.

  1. Numerical analysis of palynological data from Neogene fluvial sediments as evidence for rainforest dynamics in western Amazonia

    NASA Astrophysics Data System (ADS)

    Salamanca, Sonia; van Manen, Milan; Hoorn, Carina

    2014-05-01

    Deep-time records that give an insight into the composition and dynamics of the ancestral Amazon rain forest are rare. Yet to understand the modern biodiversity patterns it is important to untangle the long-term evolution of this forest. Sampling Neogene strata requires drilling operations or complex fieldwork along the rivers where outcrops generally are small. In the nineties an exceptionally good exposure of fluvial sediments of early Miocene age (17.7-16.1 Ma) was documented near the island of Mariñame (Caquetá River, Colombian Amazonia) (Hoorn, 1994). This 60 m sediment succession consists of quartz-rich sands with a circa 10 m black, sandy clay intercalation. Palynomorphs are well preserved in these organic-rich clays and palynological analysis indicated high pollen diversity and changes in composition following changes in the sedimentary environment and water composition (see van Soelen et al., this session). A numerical analysis in R (2013) of the existing data, using a number of multivariate and other statistical techniques now shows a gradient of change in the composition of the Miocene palynological assemblages. Non-metric-multidimensional scaling using distance matrixes (Oksanen, 2012) and their visualizations in correlograms (Friendly, 2002) indicate that the regional (palm) swamp forests of Mauritiides franciscoi (Mauritia), frequently found together with other palms such as Psilamonocolpites amazonicus (Euterpe?) and Psilamonocolpites rinconii, were affected by a marine incursion. The latter is suggested by the change of composition and the presence of estuarine elements such as Zonocostites ramonae (Rhizophora), foraminifer linings and dinoflagellate cysts, which became common during the marine event. In the older part of the section, and at the top, Rhoipites guianensis (Sterculiaceae/Tiliaceae) is quite abundant, in contrast with the relatively low abundance of M. franciscoi. The numerical analysis allowed us to: a) group the pollen data into 3

  2. Testing Na+ in blood

    PubMed Central

    Lava, Sebastiano A.G.; Bianchetti, Mario G.; Milani, Gregorio P.

    2017-01-01

    Abstract Both direct potentiometry and indirect potentiometry are currently used for Na+ testing in blood. These measurement techniques show good agreement as long as protein and lipid concentrations in blood remain normal. In severely ill patients, indirect potentiometry commonly leads to relevant errors in Na+ estimation: 25% of specimens show a disagreement between direct and indirect potentiometry, which is ≥4 mmol/L (mostly spuriously elevated Na+ level due to low circulating albumin concentration). There is a need for increased awareness of the poor performance of indirect potentiometry in some clinical settings.

  3. Run, hide, or fight: anti-predation strategies in endangered red-nosed cuxiú (Chiropotes albinasus, Pitheciidae) in southeastern Amazonia.

    PubMed

    Barnett, Adrian A; Silla, João M; de Oliveira, Tadeu; Boyle, Sarah A; Bezerra, Bruna M; Spironello, Wilson R; Setz, Eleonore Z F; da Silva, Rafaela F Soares; de Albuquerque Teixeira, Samara; Todd, Lucy M; Pinto, Liliam P

    2017-01-23

    Although primate predation is rarely observed, a series of primate anti-predation strategies have been described. Energetic costs of such strategies can vary from high-cost mobbing, via less costly alarm calling, to low-cost furtive concealment. Here we report the anti-predation strategies of red-nosed cuxiú, Chiropotes albinasus, based on direct observations from four study sites in southeastern Brazilian Amazonia. Over a collective period of 1255 fieldwork hours, we observed nine direct interactions between raptors (all potential predators) and red-nosed cuxiús. Of these, one (11%) resulted in predation. Raptors involved were: Harpia harpyja (four events), Leucopternis sp. (two events), Spizaëtus tyrannus (one event), and unidentified large raptors (two events). Predation attempts occurred in flooded-forest and terra firme rainforest, were directed at both adult and non-adult cuxiús, and involved both adult and juvenile raptors. Anti-predation strategies adopted by the cuxiús included: (1) group defence and mobbing behaviour (two occasions), (2) dropping into dense sub-canopy (seven occasions), (3) alarm calling (eight occasions), and (4) fleeing to, and hiding in, dense vegetation (eight occasions). During each encounter at least two of these behaviours were recorded. These are the first published records of predation, predation attempts, and anti-predator behaviour involving red-nosed cuxiú.

  4. Comparisons of dental morphology in river stingrays (Chondrichthyes: Potamotrygonidae) with new fossils from the middle Eocene of Peruvian Amazonia rekindle debate on their evolution.

    PubMed

    Adnet, Sylvain; Salas Gismondi, Rodolfo; Antoine, Pierre-Olivier

    2014-01-01

    Endemic South American river stingrays (Potamotrygonidae), which include the most diversified living freshwater chondrichthyans, were conspicuously absent from pre-Neogene deposits in South America despite the fact that recent phylogenetic analyses strongly suggest an older origination for this clade. To date, the rare representatives of this family were mostly represented by ambiguous isolated remains. Here, we report 67 isolated fossil teeth of a new obligate freshwater dasyatoid (Potamotrygon ucayalensis nov. sp) from the fossiliferous level CTA-27 (Yahuarango Formation), near Contamana, in the Peruvian Amazonia. We assigned this sample to a new representative of Potamotrygon by comparison with numerous fresh jaws of living specimens of Potamotrygonidae, thus providing the first detailed review of dental morphology for this poorly understood clade. These new fossils fill a long stratigraphic gap by extending the family range down to the middle Eocene (~41 Mya). Moreover, the relative modernity and diversity in tooth morphology among Eocene freshwater stingrays (including Potamotrygon ucayalensis nov. sp. and coeval North American dasyatoids) indicate that the hypothetically marine ancestor of potamotrygonids probably invaded the rivers earlier than in the middle Eocene. The first potamotrygonids and affiliates were possibly more generalized and less endemic than now, which is consistent with an opportunistic filling of vacated ecospace.

  5. Zebragryllus Desutter-Grandcolas & Cadena-Casteñada, n.gen. a new Gryllinae genus from Eastern and Western Amazonia, South America (Orthoptera, Grylloidea, Gryllidae).

    PubMed

    Desutter-Grandcolas, Laure; Cadena-Castañeda, Oscar J; Jaiswara, Ranjana; Anso, Jeremy

    2014-02-24

    We describe a new genus of grylline cricket, Zebragryllus Desutter-Grandcolas & Cadena-Casteñada n. gen., from the Neotropical Region, using characters of morphology and male genitalia; genitalic characters clearly show that Zebragryllus n. gen. is closely related to Anurogryllus Saussure, 1878. Six species are described as new to science, originating from western (Peru, Colombia) and eastern (French Guiana) Amazonia: Zebragryllus fuscus Desutter-Grandcolas, n. sp., Z. guianensis Desutter-Grandcolas, n. sp., Z. intermedius Desutter-Grandcolas, n. sp., Zebragryllus nauta Desutter-Grandcolas, n. sp., Zebragryllus nouragui Desutter-Grandcolas, n. sp., and Zebragryllus wittoto Desutter-Grandcolas and Cadena-Casteñada, n. sp., type species of the genus. They are characterized by their size, coloration (shining black, most often with white patterns of coloration, hence the genus name), and male and female genitalia. The calling songs of Z. guianensis Desutter-Grandcolas, n. sp., Z. intermedius Desutter-Grandcolas, n. sp., Z. nouragui Desutter-Grandcolas, n. sp., and Z. wittoto Desutter-Grandcolas and Cadena-Casteñada, n. sp. are described. An identification key is proposed for both males and females.

  6. Simulating deforestation and carbon loss in Amazonia: impacts in Brazil's Roraima state from reconstructing Highway BR-319 (Manaus-Porto Velho).

    PubMed

    Barni, Paulo Eduardo; Fearnside, Philip Martin; Graça, Paulo Maurício Lima de Alencastro

    2015-02-01

    Reconstruction of Highway BR-319 (Manaus-Porto Velho) would allow for access from the "arc of deforestation" in the southern part of Brazil's Amazon region to vast blocks of forests in central and northern Amazonia. Building roads is known to be a major driver of deforestation, allowing entry of squatters, and other actors. Rather than deforestation along the highway route, here we consider the road's potential for stimulating deforestation in a separate location, approximately 550 km north of BR-319's endpoint in Manaus. Reconstructing BR-319 has great potential impact to start a new wave of migration to this remote region. The southern portion of the state of Roraima, the focus of our study, is already connected to Manaus by Highway BR-174. We modeled deforestation in southern Roraima and simulated carbon emissions between 2007 and 2030 under four scenarios. Simulations used the AGROECO model in DINAMICA-EGO © software. Two scenarios were considered with reconstruction of BR-319 and two without this road connection. For each of the two possibilities regarding BR-319, simulations were developed for (1) a "conservation" (CONSERV) scenario that assumes the creation of a series of protected areas, and (2) a "business-as-usual" (BAU) scenario that assumes no additional protected areas. Results show that by 2030, with BR-319 rebuilt, deforestation carbon emissions would increase between 19% (CONSERV) and 42% (BAU) over and above those corresponding to no-road scenarios.

  7. Diversity and three-dimensional structures of the alpha Mcr of the methanogenic Archaea from the anoxic region of Tucuruí Lake, in Eastern Brazilian Amazonia

    PubMed Central

    Santana, Priscila Bessa; Junior, Rubens Ghilardi; Alves, Claudio Nahum; Silva, Jeronimo Lameira; McCulloch, John Anthony; Schneider, Maria Paula Cruz; da Costa da Silva, Artur

    2012-01-01

    Methanogenic archaeans are organisms of considerable ecological and biotechnological interest that produce methane through a restricted metabolic pathway, which culminates in the reaction catalyzed by the Methyl-coenzyme M reductase (Mcr) enzyme, and results in the release of methane. Using a metagenomic approach, the gene of the α subunit of mcr (mcrα) was isolated from sediment sample from an anoxic zone, rich in decomposing organic material, obtained from the Tucuruí hydroelectric dam reservoir in eastern Brazilian Amazonia. The partial nucleotide sequences obtained were 83 to 95% similar to those available in databases, indicating a low diversity of archaeans in the reservoir. Two orders were identified - the Methanomicrobiales, and a unique Operational Taxonomic Unit (OTU) forming a clade with the Methanosarcinales according to low bootstrap values. Homology modeling was used to determine the three-dimensional (3D) structures, for this the partial nucleotide sequence of the mcrα were isolated and translated on their partial amino acid sequences. The 3D structures of the archaean Mcrα observed in the present study varied little, and presented approximately 70% identity in comparison with the Mcrα of Methanopyrus klanderi. The results demonstrated that the community of methanogenic archaeans of the anoxic C1 region of the Tucurui reservoir is relatively homogeneous. PMID:22481885

  8. Ecological responses to el Niño-induced surface fires in central Brazilian Amazonia: management implications for flammable tropical forests.

    PubMed Central

    Barlow, Jos; Peres, Carlos A

    2004-01-01

    Over the past 20 years the combined effects of El Niño-induced droughts and land-use change have dramatically increased the frequency of fire in humid tropical forests. Despite the potential for rapid ecosystem alteration and the current prevalence of wildfire disturbance, the consequences of such fires for tropical forest biodiversity remain poorly understood. We provide a pan-tropical review of the current state of knowledge of these fires, and include data from a study in a seasonally dry terra firme forest of central Brazilian Amazonia. Overall, this study supports predictions that rates of tree mortality and changes in forest structure are strongly linked to burn severity. The potential consequences for biomass loss and carbon emissions are explored. Despite the paucity of data on faunal responses to tropical forest fires, some trends are becoming apparent; for example, large canopy frugivores and understorey insectivorous birds appear to be highly sensitive to changes in forest structure and composition during the first 3 years after fires. Finally, we appraise the management implications of fires and evaluate the viability of techniques and legislation that can be used to reduce forest flammability, prevent anthropogenic ignition sources from coming into contact with flammable forests and aid the post-fire recovery process. PMID:15212091

  9. Simulating Deforestation and Carbon Loss in Amazonia: Impacts in Brazil's Roraima State from Reconstructing Highway BR-319 (Manaus-Porto Velho)

    NASA Astrophysics Data System (ADS)

    Barni, Paulo Eduardo; Fearnside, Philip Martin; Graça, Paulo Maurício Lima de Alencastro

    2015-02-01

    Reconstruction of Highway BR-319 (Manaus-Porto Velho) would allow for access from the "arc of deforestation" in the southern part of Brazil's Amazon region to vast blocks of forests in central and northern Amazonia. Building roads is known to be a major driver of deforestation, allowing entry of squatters, and other actors. Rather than deforestation along the highway route, here we consider the road's potential for stimulating deforestation in a separate location, approximately 550 km north of BR-319's endpoint in Manaus. Reconstructing BR-319 has great potential impact to start a new wave of migration to this remote region. The southern portion of the state of Roraima, the focus of our study, is already connected to Manaus by Highway BR-174. We modeled deforestation in southern Roraima and simulated carbon emissions between 2007 and 2030 under four scenarios. Simulations used the AGROECO model in DINAMICA-EGO software. Two scenarios were considered with reconstruction of BR-319 and two without this road connection. For each of the two possibilities regarding BR-319, simulations were developed for (1) a "conservation" (CONSERV) scenario that assumes the creation of a series of protected areas, and (2) a "business-as-usual" (BAU) scenario that assumes no additional protected areas. Results show that by 2030, with BR-319 rebuilt, deforestation carbon emissions would increase between 19 % (CONSERV) and 42 % (BAU) over and above those corresponding to no-road scenarios.

  10. Ecological responses to el Niño-induced surface fires in central Brazilian Amazonia: management implications for flammable tropical forests.

    PubMed

    Barlow, Jos; Peres, Carlos A

    2004-03-29

    Over the past 20 years the combined effects of El Niño-induced droughts and land-use change have dramatically increased the frequency of fire in humid tropical forests. Despite the potential for rapid ecosystem alteration and the current prevalence of wildfire disturbance, the consequences of such fires for tropical forest biodiversity remain poorly understood. We provide a pan-tropical review of the current state of knowledge of these fires, and include data from a study in a seasonally dry terra firme forest of central Brazilian Amazonia. Overall, this study supports predictions that rates of tree mortality and changes in forest structure are strongly linked to burn severity. The potential consequences for biomass loss and carbon emissions are explored. Despite the paucity of data on faunal responses to tropical forest fires, some trends are becoming apparent; for example, large canopy frugivores and understorey insectivorous birds appear to be highly sensitive to changes in forest structure and composition during the first 3 years after fires. Finally, we appraise the management implications of fires and evaluate the viability of techniques and legislation that can be used to reduce forest flammability, prevent anthropogenic ignition sources from coming into contact with flammable forests and aid the post-fire recovery process.

  11. Influence of pre-seasonal conditions on late wet season arrival and its implications to predictive understanding of the droughts over southern Amazonia

    NASA Astrophysics Data System (ADS)

    Yin, L.; Fu, R.

    2011-12-01

    Our recent analysis suggests that the increase of drought severity in the southern Amazon during recent decades is mainly contributed by a delaying of wet season onset and resulted shortening of the wet season. Using a suite of observations, we found that a delay of wet season onset is significantly correlated with anomalous pre-seasonal conditions. In particular, a poleward shift of the southern hemispheric subtropical jet, and an increase of convective inhibition energy (CINE) during the three months prior to the wet season onset date appear to be significantly correlated with the subsequently delay of wet season onset. Canonical correlation analysis suggests that this correlation between the pre-seasonal large-scale circulation and near surface atmosphere thermodynamic condition is relatively insensitive to the data and parameters we choose to represent the subtropical jets. We will discuss physical mechanisms of this observed correlation between pre-seasonal climate conditions and delay of wet season onsets and potential of using this correlation as a predicting factor in determining the likelihood of delaying in wet season onset over southern Amazonia. We will also evaluate whether this relationship is adequately represented in climate models.

  12. New species of Ameloblastella Kritsky, Mendoza-Franco & Scholz, 2000 and Cosmetocleithrum Kritsky, Thatcher & Boeger, 1986 (Monogenea: Dactylogyridae) infecting the gills of catfishes (Siluriformes) from the Peruvian Amazonia.

    PubMed

    Mendoza-Franco, Edgar F; Mendoza-Palmero, Carlos A; Scholz, Tomáš

    2016-11-01

    During a research on gill ectoparasites of siluriform fishes from the Peruvian Amazonia, the following monogeneans were found: Ameloblastella edentensis n. sp. from Hypophthalmus edentatus Spix & Agassiz; Ameloblastella peruensis n. sp. from Hypophthalmus sp.; Ameloblastella formatrium n. sp. from Pimelodidae gen. sp. (type-host) and Duopalatinus cf. peruanus Eigenmann & Allen; Ameloblastella unapioides n. sp. from Sorubim lima (Bloch & Schneider) (type-host) and Pimelodus sp; Cosmetocleithrum tortum n. sp. from Nemadoras hemipeltis (Eigenmann); and Cosmetocleithrum bifurcum n. sp. from Hassar orestis (Steindachner) (both Doradidae). All new species described herein are mainly differentiated from their congeners based on the morphology of the copulatory complex. The pimelodids H. edentatus and S. lima, and the doradids N. hemipeltis and H. orestis represent new hosts species for species of Ameloblastella Kritsky, Mendoza-Franco & Scholz, 2000 and Cosmetocleithrum Kritsky, Thatcher & Boeger, 1986, respectively. The morphological diagnosis of the present species of Ameloblastella and Cosmetocleithrum also supported by a previous molecular analysis of these species is briefly discusssed herein.

  13. The genus Manota Williston (Diptera: Mycetophilidae) in Peruvian Amazonia, with description of sixteen new species and notes on local species richness.

    PubMed

    Hippa, Heikki; Kurina, Olavi; Sääksjärvi, Ilari E

    2017-02-21

    A comprehensive study of material of the worldwide fungus gnat genus Manota Williston, sampled from the Allpahuayo-Mishana National Reserve in Peruvian Amazonia, was conducted. The following 16 species are described as new: M. aligera sp. n., M. aristoseta sp. n., M. calva sp. n., M. ciliata sp. n., M. exigua sp. n., M. digitata sp. n., M. flabellata sp. n., M. iquitosensis sp. n., M. limulata sp. n., M. micella sp. n., M. minutula sp. n., M. nuda sp. n., M. parvula sp. n., M. pauloides sp. n., M. pustulosa sp. n. and M. serrulata sp. n. In addition, the following 16 species are recorded: M. acuminata Jaschhof & Hippa, 2005, M. acutistylus Jaschhof & Hippa, 2005, M. anfracta Hippa & Kurina, 2013, M. appendiculata Hippa & Kurina, 2013, M. aristata Hippa & Kurina, 2013, M. bisulca Hippa & Kurina, 2013, M. diversiseta Jaschhof & Hippa, 2005, M. iota Hippa & Kurina, 2013, M. micula Hippa & Kurina, 2013, M. papillosa Hippa & Kurina, 2013, M. paula Hippa & Kurina, 2013, M. penicillata Jaschhof & Hippa, 2005, M. pisinna Hippa & Kurina, 2013, M. quantula Hippa & Kurina, 2013, M. spinosa Jaschhof & Hippa, 2005 and M. virgata Hippa & Kurina, 2013. Altogether 67 species of Manota are now known from the Neotropical region.

  14. Description and phylogenetic relationships of a new genus and two new species of lizards from Brazilian Amazonia, with nomenclatural comments on the taxonomy of Gymnophthalmidae (Reptilia: Squamata).

    PubMed

    Colli, Guarino R; Hoogmoed, Marinus S; Cannatella, David C; Cassimiro, José; Gomes, Jerriane Oliveira; Ghellere, José Mário; Gomes, Jerriane Oliveira; Ghellere, José Mário; Nunes, Pedro M Sales; Pellegrino, Kátia C M; Salerno, Patricia; Souza, Sergio Marques De; Rodrigues, Miguel Trefaut

    2015-08-18

    We describe a new genus and two new species of gymnophthalmid lizards based on specimens collected from Brazilian Amazonia, mostly in the "arc of deforestation". The new genus is easily distinguished from other Gymnophthalmidae by having very wide, smooth, and imbricate nuchals, arranged in two longitudinal and 6-10 transverse rows from nape to brachium level, followed by much narrower, strongly keeled, lanceolate, and mucronate scales. It also differs from all other Gymnophthalmidae, except Iphisa, by the presence of two longitudinal rows of ventrals. The new genus differs from Iphisa by having two pairs of enlarged chinshields (one in Iphisa); posterior dorsal scales lanceolate, strongly keeled and not arranged in longitudinal rows (dorsals broad, smooth and forming two longitudinal rows), and lateral scales keeled (smooth). Maximum parsimony, maximum likelihood, and Bayesian phylogenetic analyses based on morphological and molecular data indicate the new species form a clade that is most closely related to Iphisa. We also address several nomenclatural issues and present a revised classification of Gymnophthalmidae.

  15. Sequential hair mercury in mothers and children from a traditional riverine population of the Rio Tapajós, Amazonia: seasonal changes.

    PubMed

    Malm, Olaf; Dórea, José G; Barbosa, Antonio C; Pinto, Fernando N; Weihe, Pal

    2010-10-01

    Riverine populations of the Brazilian Amazon depend on fish for their principal source of protein, which changes in availability with seasonal fluctuations in the aquatic ecosystem. We report seasonal (high and low waters) and interannual changes in total mercury and methylmercury concentrations in hair of subsistence fish-eaters from a traditional riverine village on the banks of the Rio Tapajós in the Brazilian Amazonia. Retrospective exposure assessment was conducted from hair concentrations in segments representative of 2 years. A total of 32 mothers and their 51 children were studied. They reported high fish consumption (4-14 times a week). Ranges of total mercury and methylmercury concentrations in hair were 1.0-51.0 and 0.5-41.4microgg(-1), with means of 12.4 and 10.2microgg(-1), respectively. The relative mean value for methylmercury was 80%. There was a significant correlation between mothers and children for both total-Hg (r=0.4826; P=0.003) and methyl-Hg (r=0.5214; P=0.004). Mercury concentrations along hair strands of individuals showed significant variation coinciding with seasonal high and low waters. The changes in the aquatic environment impacted fish species availability, which is reflected in the total and MeHg concentrations in hair.

  16. Learning to Question: The Roles of Multiple Hypotheses, Successive Approximations, Balloons and Toilet Paper in University Science Programs of Southwestern Amazonia

    NASA Astrophysics Data System (ADS)

    Brown, I. Foster

    2008-06-01

    Learning to question is essential for determining pathways of conservation and development in southwestern Amazonia during a time of rapid global environmental change. Teaching such an approach in graduate science programs in regional universities can be done using play-acting and simulation exercises. Multiple working hypotheses help students learn to question their own research results and expert witnesses. The method of successive approximations enables students to question the results of complex calculations, such as estimates of forest biomass. Balloons and rolls of toilet paper provide means of questioning two-dimensional representations of a three-dimensional Earth and the value of pi. Generation of systematic errors can illustrate the pitfalls of blind acceptance of data. While learning to question is essential, it is insufficient by itself; students must also learn how to be solutionologists in order to satisfy societal demands for solutions to environmental problems. A little irreverence can be an excellent didactic tool for helping students develop the skills necessary to lead conservation and development efforts in the region.

  17. Species diversity of edaphic mites (Acari: Oribatida) and effects of topography, soil properties and litter gradients on their qualitative and quantitative composition in 64 km² of forest in Amazonia.

    PubMed

    de Moraes, Jamile; Franklin, Elizabeth; de Morais, José Wellington; de Souza, Jorge Luiz Pereira

    2011-09-01

    Small-scale spatial distribution of oribatid mites has been investigated in Amazonia. In addition, medium- and large-scale studies are needed to establish the utility of these mites in detecting natural environmental variability, and to distinguish this variability from anthropogenic impacts. We are expanding the knowledge about oribatid mites in a wet upland forest reserve, and investigate whether a standardized and integrated protocol is an efficient way to assess the effects of environmental variables on their qualitative and quantitative composition on a large spatial scale inside an ecological reserve in Central Amazonia, Brazil. Samples for Berlese-Tullgren extraction were taken in 72 plots of 250 × 6 m distributed over 64 km(2). In total 3,182 adult individuals, from 82 species and 79 morphospecies were recorded, expanding the number of species known in the reserve from 149 to 254. Galumna, Rostrozetes and Scheloribates were the most speciose genera, and 57 species were rare. Rostrozetes ovulum, Pergalumna passimpuctata and Archegozetes longisetosus were the most abundant species, and the first two were the most frequent. Species number and abundance were not correlated with clay content, slope, pH and litter quantity. However, Principal Coordinate Analysis indicated that as the percentage of clay content, litter quantity and pH changed, the oribatid mite qualitative and quantitative composition also changed. The standardized protocol effectively captured the diversity, as we collected one of the largest registers of oribatid mites' species for Amazonia. Moreover, biological and ecological data were integrated to capture the effects of environmental variables accounting for their diversity and abundance.

  18. Comment by J.P. Figueiredo, & Hoorn, C. on 'Late Miocene sedimentary environments in south-western Amazonia (Solimões Formation; Brazil)' by Martin Gross, Werner E. Piller, Maria Ines Ramos, Jackson Douglas da Silva Paz

    NASA Astrophysics Data System (ADS)

    Figueiredo, Jorge Jesus Picanço

    2012-04-01

    In their paper Gross et al., 2011 present an excellent description of a series of outcrops from the Eirunepe region in western Amazonia (Brazil). The authors interpret these sediments as relics of a Late Miocene anastomosing fluvial system and conclude that the paleogeography of the entire western Amazon region must have been characterized by this environmental setting. They also imply that therefore a long-lived lake system - or megawetland - never existed. We contend this assumption for some reasons, amongst them, the most important are: (1) this is an inconsistent overgeneralized conclusion; (2) The authors make references to previous scientific works we published which we consider incorrect, and therefore can mislead their readers.

  19. Low-Cost Evaluation of EO-1 Hyperion and ALI for Detection and Biophysical Characterization of Forest Logging in Amazonia (NCC5-481)

    NASA Technical Reports Server (NTRS)

    Asner, Gregory P.; Keller, Michael M.; Silva, Jose Natalino; Zweede, Johan C.; Pereira, Rodrigo, Jr.

    2002-01-01

    quantify both the presence and degree of structural disturbance caused by various logging regimes. Our quantitative assessment of Hyperion hyperspectral and ALI multi-spectral data for the detection and structural characterization of selective logging in Amazonia will benefit from data collected through an ongoing project run by the Tropical Forest Foundation, within which we have developed a study of the canopy and landscape biophysics of conventional and reduced-impact logging. We will add to our base of forest structural information in concert with an EO-1 overpass. Using a photon transport model inversion technique that accounts for non-linear mixing of the four biogeophysical indicators, we will estimate these parameters across a gradient of selective logging intensity provided by conventional and reduced impact logging sites. We will also compare our physical ly-based approach to both conventional (e.g., NDVI) and novel (e.g., SWIR-channel) vegetation indices as well as to linear mixture modeling methods. We will cross-compare these approaches using Hyperion and ALI imagers to determine the strengths and limitations of these two sensors for applications of forest biophysics. This effort will yield the first physical ly-based, quantitative analysis of the detection and intensity of selective logging in Amazonia, comparing hyperspectral and improved multi-spectral approaches as well as inverse modeling, linear mixture modeling, and vegetation index techniques.

  20. Are The Large-Scale Biosphere-Atmosphere Experiment In Amazonia (LBA) Representative Of Long-Term Climatology? A Study Using Climate Weather Stations In Brazil.

    NASA Astrophysics Data System (ADS)

    Rosolem, R.; Shuttleworth, W. J.; Goncalves, L. G.

    2007-12-01

    The Large-Scale Biosphere-Atmosphere Experiment in Amazonia has already contributed understanding of the flux exchange between the Amazonian rainforest and atmosphere and other significant components of the ecohydrometeorological system, and it will continue to do so. However, when considering LBA-derived information on whether the Amazon is a source or sink of carbon, or whether land use changes in the Amazon are affecting the local and perhaps global climate, it is important to characterize the period during which the LBA project has been carried out in terms of its climatological context. In other words, to address the question "How does the climate during the LBA data collection period compare with the long-term climatology in Amazon." Such information is not only useful for future project planning but is crucial information for modeling purposes: the calibration or validation of models using LBA data may be influenced by the climate conditions prevalent when these data were collected. This investigates the extent to which the actual period of data collection at LBA sites is representative of the long-term climatology for the sites. The research uses long-term weather station data taken from the databases of Brazilian National Water Agency (Agencia Nacional de Aguas - ANA) and National Oceanic and Atmospheric Administration - National Climatic Data Center division (NOAA-NCDC) for stations located near the Sao Gabriel da Cachoeira, Manaus, Santarem, Caxiuana, Jaru, Sinop, and Bananal LBA sites, and compares these weather station data during the LBA data collection period with the entire dataset available for each weather station. Analysis of the precipitation records demonstrates that the precipitation climate during the LBA study period was not significant different from the long- term climatology at all the LBA sites but that at a few sites the temperature climate during LBA was statistically different.

  1. Local perceptions as a guide for the sustainable management of natural resources: empirical evidence from a small-scale society in Bolivian Amazonia

    PubMed Central

    Fernández-Llamazares, Álvaro; Díaz-Reviriego, Isabel; Guèze, Maximilien; Cabeza, Mar; Pyhälä, Aili; Reyes-García, Victoria

    2016-01-01

    Research on natural resource management suggests that local perceptions form the basis upon which many small-scale societies monitor availability and change in the stock of common-pool natural resources. In contrast, this literature debates whether local perceptions can be effective in guiding the sustainable management of natural resources. With empirical evidence on this matter still highly limited, this work explores the role of local perceptions as drivers of harvesting and management behavior in a small-scale society in Bolivian Amazonia. We conducted structured interviews to capture local perceptions of availability and change in the stock of thatch palm (Geonoma deversa) amongst the Tsimane’, an indigenous society of foragers-horticulturalists (n = 296 adults in 13 villages). We analyzed whether perceptions of availability match estimates of abundance obtained from ecological data and whether differences in perception help to explain harvesting behavior and local management of thatch palm. Perceptions of availability of G. deversa are highly contingent upon the social, economic and cultural conditions within which the Tsimane’ have experienced changes in the availability of the resource, thus giving a better reflection of the historical, rather than of the ecological, dimensions of the changes undergone. While local perceptions might fall short in precision when scrutinized from an ecological standpoint, their importance in informing sustainable management should not be underestimated. Our findings show that most of the harvesting and management actions that the Tsimane’ undertake are, at least partially, shaped by their local perceptions. This paper contributes to the broader literature on natural resource management by providing empirical evidence of the critical role of local perceptions in promoting collective responses for the sustainable management of natural resources. PMID:27660639

  2. Close evolutionary affinities between freshwater corbulid bivalves from the Neogene of western Amazonia and Paleogene of the northern Great Plains, USA

    NASA Astrophysics Data System (ADS)

    Anderson, Laurie C.; Hartman, Joseph H.; Wesselingh, Frank

    2006-03-01

    Freshwater corbulid bivalves found in Miocene deposits of western Amazonia have been considered products of an endemic radiation of a marine clade within the large lacustrine system occupying the region at that time. Our reexamination of Paleocene freshwater corbulids of the Tongue River Formation of western North Dakota and eastern Montana, however, extends the stratigraphic and geographic range of three Amazonian taxa— Pachydon, Ostomya, and Anticorbula—to the Paleocene of the northern Great Plains of the United States. Both Paleocene and Miocene freshwater corbulid taxa occur in large freshwater systems with an intermittent marine connection. To test the phylogenetic relationships of one particularly widespread Paleocene species ( Pachydon mactriformis), we conducted cladistic analyses using maximum parsimony and heuristic searches of matrices of conchologic characters. Seven species of Pachydon and Pebasia dispar from the western Amazonian Neogene, Pachydon mactriformis from the Paleocene of North Dakota, representative species of eight neotropical marine corbulid genera, and three additional corbulid taxa were included. Corbula was the outgroup. All analyses produced similar regions of stability within trees. One such area is a Pachydon crown group that includes P. mactriformis, indicating that Paleocene and Miocene Pachydon are not convergent. Our results also indicate that Pachydon does not represent a separate basal radiation within the family. However, we have not resolved a robust sister clade relationship for the Pachydon crown group. Two Amazonian Neogene taxa do not fall within the Pachydon crown group, and their phylogenetic position is not resolved. At this time, we do not have sufficient evidence to refine the definitions of Pachydon and Pachydontinae as monophyletic clades. Although we have evidence that three genera of corbulid bivalves ( Pachydon, Ostomya, and Anticorbula) in the Pebas Formation are not endemic and have long geologic

  3. The dynamic variability of dissolved and particulate organic matter and nutrients in a changing tropical rainforest: First results from a new geochemical program in northern Amazonia, Guyana

    NASA Astrophysics Data System (ADS)

    Pereira, R.; Bovolo, I.; Parkin, G.; Wagner, T.

    2010-12-01

    Current knowledge suggests that the two largest threats to ecosystems are changes in land use and climate variability. Focussing on the tropics, these changes put an immediate threat on the health and fate of rainforest ecosystems. It has been shown for Amazonia that natural seasonal variability when linked to transitional periods of extreme weather events, can trigger an almost instantaneous and large increase in the release of nutrients and carbon from soils into rivers driven by variation in precipitation (Raymond, 2005; Mayorga et al., 2005). A new hydrology and climate monitoring program at the Iwokrama International Centre for Rainforest Conservation and Development in Guyana will investigate the ability of the rainforest and its soils to generate, store and recycle carbon, nutrients and water over a multi-year period; and to address the issue of the forests response to combined natural and anthropogenic induced change. It is important to establish the range of variability between wet and dry seasons, thereby characterising the current state of the forest and how it responds to external forcing. A detailed understanding of the quality and cycling of key soil properties, including carbon and nutrients, is critical to assess the status and potential change of forest vegetation and ecosystems. Comparisons of the processes and impacts of natural climate variability and forestry activity in pristine and sustainably used forest areas will be made. We introduce the conceptual strategy and experimental design of the new research program and present first geochemical results based on field work in March and July 2010 comparing dry and wet seasons. The preliminary analyses of elemental and spectrophotometric (UV-absorbance) data generated from top soil, river water and river bed sediments from the Burro Burro River transect through pristine and managed forest will be presented. The data will be used to assess the nature and variability of low and high molecular

  4. Anthropogenic landscape in southeastern Amazonia: contemporary impacts of low-intensity harvesting and dispersal of Brazil nuts by the Kayapó Indigenous people.

    PubMed

    Ribeiro, Maria Beatriz N; Jerozolimski, Adriano; de Robert, Pascale; Salles, Nilson V; Kayapó, Biribiri; Pimentel, Tania P; Magnusson, William E

    2014-01-01

    Brazil nut, the Bertholletia excelsa seed, is one of the most important non-timber forest products in the Amazon Forest and the livelihoods of thousands of traditional Amazonian families depend on its commercialization. B. excelsa has been frequently cited as an indicator of anthropogenic forests and there is strong evidence that past human management has significantly contributed to its present distribution across the Amazon, suggesting that low levels of harvesting may play a positive role in B. excelsa recruitment. Here, we evaluate the effects of Brazil nut harvesting by the Kayapó Indigenous people of southeastern Amazonia on seedling recruitment in 20 B. excelsa groves subjected to different harvesting intensities, and investigated if management by harvesters influences patterns of B. excelsa distribution. The number of years of low-intensity Brazil nut harvesting by the Kayapó over the past two decades was positively related to B. excelsa seedling density in groves. One of the mechanisms behind the higher seedling density in harvested sites seems to be seed dispersal by harvesters along trails. The Kayapó also intentionally plant B. excelsa seeds and seedlings across their territories. Our results show not only that low-intensity Brazil nut harvesting by the Kayapó people does not reduce recruitment of seedlings, but that harvesting and/or associated activities conducted by traditional harvesters may benefit B. excelsa beyond grove borders. Our study supports the hypothesis that B. excelsa dispersal throughout the Amazon was, at least in part, influenced by indigenous groups, and strongly suggests that current human management contributes to the maintenance and formation of B. excelsa groves. We suggest that changes in Brazil nut management practices by traditional people to prevent harvesting impacts may be unnecessary and even counterproductive in many areas, and should be carefully evaluated before implementation.

  5. Anthropogenic Landscape in Southeastern Amazonia: Contemporary Impacts of Low-Intensity Harvesting and Dispersal of Brazil Nuts by the Kayapó Indigenous People

    PubMed Central

    Ribeiro, Maria Beatriz N.; Jerozolimski, Adriano; de Robert, Pascale; Salles, Nilson V.; Kayapó, Biribiri; Pimentel, Tania P.; Magnusson, William E.

    2014-01-01

    Brazil nut, the Bertholletia excelsa seed, is one of the most important non-timber forest products in the Amazon Forest and the livelihoods of thousands of traditional Amazonian families depend on its commercialization. B. excelsa has been frequently cited as an indicator of anthropogenic forests and there is strong evidence that past human management has significantly contributed to its present distribution across the Amazon, suggesting that low levels of harvesting may play a positive role in B. excelsa recruitment. Here, we evaluate the effects of Brazil nut harvesting by the Kayapó Indigenous people of southeastern Amazonia on seedling recruitment in 20 B. excelsa groves subjected to different harvesting intensities, and investigated if management by harvesters influences patterns of B. excelsa distribution. The number of years of low-intensity Brazil nut harvesting by the Kayapó over the past two decades was positively related to B. excelsa seedling density in groves. One of the mechanisms behind the higher seedling density in harvested sites seems to be seed dispersal by harvesters along trails. The Kayapó also intentionally plant B. excelsa seeds and seedlings across their territories. Our results show not only that low-intensity Brazil nut harvesting by the Kayapó people does not reduce recruitment of seedlings, but that harvesting and/or associated activities conducted by traditional harvesters may benefit B. excelsa beyond grove borders. Our study supports the hypothesis that B. excelsa dispersal throughout the Amazon was, at least in part, influenced by indigenous groups, and strongly suggests that current human management contributes to the maintenance and formation of B. excelsa groves. We suggest that changes in Brazil nut management practices by traditional people to prevent harvesting impacts may be unnecessary and even counterproductive in many areas, and should be carefully evaluated before implementation. PMID:25029191

  6. Activity budget and social interactions in semi-captive gray woolly monkeys (Lagothrix lagotricha cana) living in an ex situ conservation area in Central Amazonia.

    PubMed

    Cartagena-Matos, Bárbara; Gasnier, Thierry; Cravo-Mota, Mariana; Martins Bezerra, Bruna

    2017-01-01

    Areas holding primates in semi-captivity conditions represent an excellent opportunity for collecting data on rare, little known, and endangered taxa, contributing with insightful information to help in their conservation. Here, we present information on the activity budget and social interactions of the elusive gray woolly monkeys, Lagothrix lagotricha cana, in an ex situ conservation area in central Amazonia. We studied the behavior of 18 semi-captive individuals through instantaneous scan and focal animal samplings during 4 months in the wet season. The most frequent activity registered was resting (45%). The remaining time was dedicated to foraging (29%), travelling (23%), social interactions (3%), and self-grooming (1%). Resting and travelling time may be correlated to fruit availability in the area through different seasons. Huddling was the most frequent social interaction, being more common from young individuals toward adult females, which may be associated with breastfeeding. Playing was more common among young males. This activity prepares them to defend themselves from possible attacks and allows them to develop their role in the social group, as future adult males. Aggression was most frequent among adults, primarily from males toward females, likely to demonstrate their dominance over females. Social grooming occurred predominantly from mother to offspring. This interaction can reduce the risk of young predation, directly increasing the female reproductive success. Our data not only add to our understanding of the sociality and behaviors of the genus Lagothrix, but may also serve as a tool to identify environments that support an adequate activity budget for these monkeys. Zoo Biol. 36:21-29, 2017. © 2016 Wiley Periodicals, Inc.

  7. Local perceptions as a guide for the sustainable management of natural resources: empirical evidence from a small-scale society in Bolivian Amazonia.

    PubMed

    Fernández-Llamazares, Álvaro; Díaz-Reviriego, Isabel; Guèze, Maximilien; Cabeza, Mar; Pyhälä, Aili; Reyes-García, Victoria

    2016-03-01

    Research on natural resource management suggests that local perceptions form the basis upon which many small-scale societies monitor availability and change in the stock of common-pool natural resources. In contrast, this literature debates whether local perceptions can be effective in guiding the sustainable management of natural resources. With empirical evidence on this matter still highly limited, this work explores the role of local perceptions as drivers of harvesting and management behavior in a small-scale society in Bolivian Amazonia. We conducted structured interviews to capture local perceptions of availability and change in the stock of thatch palm (Geonoma deversa) amongst the Tsimane', an indigenous society of foragers-horticulturalists (n = 296 adults in 13 villages). We analyzed whether perceptions of availability match estimates of abundance obtained from ecological data and whether differences in perception help to explain harvesting behavior and local management of thatch palm. Perceptions of availability of G. deversa are highly contingent upon the social, economic and cultural conditions within which the Tsimane' have experienced changes in the availability of the resource, thus giving a better reflection of the historical, rather than of the ecological, dimensions of the changes undergone. While local perceptions might fall short in precision when scrutinized from an ecological standpoint, their importance in informing sustainable management should not be underestimated. Our findings show that most of the harvesting and management actions that the Tsimane' undertake are, at least partially, shaped by their local perceptions. This paper contributes to the broader literature on natural resource management by providing empirical evidence of the critical role of local perceptions in promoting collective responses for the sustainable management of natural resources.

  8. BR-319: Brazil's Manaus-Porto Velho highway and the potential impact of linking the arc of deforestation to central amazonia.

    PubMed

    Fearnside, Philip M; de Alencastro Graça, Paulo Maurício Lima

    2006-11-01

    Brazil's BR-319 Highway linked Manaus, in the state of Amazonas, to Porto Velho, Rondônia, until it became impassable in 1988. Now it is proposed for reconstruction and paving, which would facilitate migration from the "Arc of Deforestation" in the southern part of the Amazon region to new frontiers farther north. The purpose of the highway, which is to facilitate transport to São Paulo of products from factories in the Manaus Free Trade Zone, would be better served by sending the containers by ship to the port of Santos. The lack of a land connection to Manaus currently represents a significant barrier to migration to central and northern Amazonia. Discourse regarding the highway systematically overestimates the highway's benefits and underestimates its impacts. A variety of changes would be needed prior to paving the highway if these potential impacts are to be attenuated. These include zoning, reserve creation, and increased governance in various forms, including deforestation licensing and control programs. More fundamental changes are also needed, especially the abandonment of the long-standing tradition in Brazil of granting squatters' rights to those who invade public land. Organizing Amazonian occupation in such a way that road construction and improvement cease to lead to explosive and uncontrolled deforestation should be a prerequisite for approval of the BR-319 and other road projects for which major impacts are expected. These projects could provide the impetus that is needed to achieve the transition away from appropriation of public land by both small squatters and by grileiros (large-scale illegal claimants). A delay in reconstructing the highway is advisable until appropriate changes can be effected.

  9. 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?

    NASA Astrophysics Data System (ADS)

    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.

  10. Na+ coordination at the Na2 site of the Na+/I- symporter.

    PubMed

    Ferrandino, Giuseppe; Nicola, Juan Pablo; Sánchez, Yuly E; Echeverria, Ignacia; Liu, Yunlong; Amzel, L Mario; Carrasco, Nancy

    2016-09-13

    The sodium/iodide symporter (NIS) mediates active I(-) transport in the thyroid-the first step in thyroid hormone biosynthesis-with a 2 Na(+): 1 I(-) stoichiometry. The two Na(+) binding sites (Na1 and Na2) and the I(-) binding site interact allosterically: when Na(+) binds to a Na(+) site, the affinity of NIS for the other Na(+) and for I(-) increases significantly. In all Na(+)-dependent transporters with the same fold as NIS, the side chains of two residues, S353 and T354 (NIS numbering), were identified as the Na(+) ligands at Na2. To understand the cooperativity between the substrates, we investigated the coordination at the Na2 site. We determined that four other residues-S66, D191, Q194, and Q263-are also involved in Na(+) coordination at this site. Experiments in whole cells demonstrated that these four residues participate in transport by NIS: mutations at these positions result in proteins that, although expressed at the plasma membrane, transport little or no I(-) These residues are conserved throughout the entire SLC5 family, to which NIS belongs, suggesting that they serve a similar function in the other transporters. Our findings also suggest that the increase in affinity that each site displays when an ion binds to another site may result from changes in the dynamics of the transporter. These mechanistic insights deepen our understanding not only of NIS but also of other transporters, including many that, like NIS, are of great medical relevance.

  11. Trying to Learn Lessons for Response to Extreme Events: Paradigm Shifts Affecting Civil Defense in the Trinational Region of Southwestern Amazonia

    NASA Astrophysics Data System (ADS)

    Santos, G. L. P.

    2015-12-01

    The last ten years have seen several extreme climate events in southwestern Amazonia with historic impacts. The City of Rio Branco, Capital of Acre, Brazil´s westernmost State, suffered its seventh consecutive annual flooding and its worst in March 2015. The city of Tarauacá, also in Acre, registered 12 flooding events between November 2014 and April 2015. The most recent flood of the trinational Acre River in 2015 set historic records for flood stage and number of displaced persons in Cobija, the Capital of Pando, Bolivia. From February to April 2014, floods of the Madeira River disrupted the one highway between Acre and southern Brazil. Puerto Maldonado, the capital in Madre de Dios Region of Peru had its worst flood in 50 years during 2014. In 2005 and 2010, prolonged droughts combined with ignition sources resulted in tens to hundreds of thousands of hectares of fire-damaged rainforests in the Madre de Dios, Acre and Pando (MAP) Region. The Civil Defenses in these three contiguous political units faced several abrupt paradigm shifts that affected their responses: 1) The drought of 2005 showed dramatically that regional rainforests do burn; 2) The recent flooding history, particularly in 2012 and 2015, demolished the cultural icon of a nine-year recurrence interval; 3) What happens outside your territory can be devastating. The Madeira River flood impeded an estimated 200 million dollars from circulating in Acre; 4) The past can be a terrible guide. For Cobija and Rio Branco, the 2015 flood was on the order of a meter higher than any other. Many home dwellers did not evacuate in time because they used past floods as a guide; 5) A collapse in communication - cell phones, land lines, and Internet - can get worse. In 2012, such a collapse occurred in two border towns for 5 days, yet in 2015 it lasted more than 11 days. Research is needed to address how institutions linked to Civil Defense can shift paradigms in time to be more effective.

  12. Microphysical And Macrophysical Characteristics Of Non-Precipitating Morning Shallow Clouds In Central Amazonia Using One-Year Of Data From GOAMAZON 2014/15 Experiment

    NASA Astrophysics Data System (ADS)

    Pauliquevis, T.; Barbosa, H. M.; Rosario, N. M. E. D.; Rizzo, L. V.; Correia, A. L.; Adams, D. K.; Calheiros, A. J. P.; Alves, C. F.

    2015-12-01

    Shallow cumulus cloud fields in Amazonia are typical of the morning hours. They play a critical role in the mean observed diurnal cycle of precipitation in the Amazon Basin, which is characterized by the occurrence of heavy precipitation events in the afternoon. Shallow clouds act both to reduce incident shortwave radiation at the surface and in the transport of humidity from the lowest portions of the troposphere to higher levels. These two processes are poorly represented in numerical models, but are critical in the transition to deep convection and associated precipitation. Numerical models have problems in properly representing shallow cumulus fields and their transition to deep precipitating convection, the net result of which is producing rainfall to early in the diurnal cycle. Due to their importance, detailed characterization of morning shallow clouds is critical for understanding the shallow-to-deep transition as well as providing for model validation purposes. In this study we report 16 month data of observations of shallow cumulus with respect to cloud cover (CC), cloud base height (CBH), liquid water path (LWP), precipitable water vapor (PWV) and GOES (Visible and IR)analysis. Results showed a consistent pattern of evolution in the cloud field throughout the morning period. After sunrise the cloud field starts to move from a random cloud field to an organized shallow clouds field. In fact, there is an absence of any pattern in CBH from 6LT to 7LT. Once some amount of radiation reaches the surface shallow convection is established around 8:00LT, when a mode of CBH at 100 m is established and rises to 900 m at noon. During this time interval, CC grows up to 50% (mean), however with significant variability and oscillations. With respect to microphysical properties, both LWP and PWV were remarkably stable for single mornings and for shallow clouds, with LWP/PWV ~ 6.10-4. All of these results are being compared with GOES observations of cloud fields (Visible

  13. The Elusive Multiplying Factor for Sustainable Development: The Case for Integrating Scientific Research and Basic Education in the MAP Region, SW Amazonia.

    NASA Astrophysics Data System (ADS)

    Brown, I.; de Los Rios, M.; Mendoza, E.; Reis, V. L.

    2005-05-01

    The Region of Madre de Dios-Peru, the State of Acre-Brazil, and the Department of Pando-Bolivia, known collectively as the trinational MAP Region, lies at the heart of Southwestern Amazonia. This region covers over 300,000 km2 with a population of 700,000 that ranges from urban dwellers to indigenous groups trying to avoid contact with industrial society. This region, home of incredible biological and cultural wealth, represents some of the economically poorest areas of the respective countries. It is also a site of accelerating global change in land-use, with three highways being developed for all-weather transport between central Brazil and Pacific ports. Our group has engaged in pilot experiments to provide regional societies with access to recent scientific results. Our objective is to help these societies in their quest to develop through: a) the use of GPS and satellite imagery for land use planning by small rural producers; b) municipal-level meetings in two countries to evaluate current problems and future land use along the inter-oceanic highway; c) the analysis of deforestation in the trinational river basin; d) dissemination via the media of imagery and analysis of fires during the burning season; and e) incorporation of nearby forests into the rural educational system. While most of these experiments have proven successful, they pale before the challenge of expanding them to become significant in changing land use and promoting sustainable development in this region. The multiplying factors need to be in the range of ten to a thousand times the size of the pilot experiments. Public policy and economic initiatives are crucial, but are often treated as the only means for such multiplication. The basic education system represents another, complementary multiplying factor. In the State of Acre, about a third of the population, 200,000, are in the K-12 school system and of these over 80% are in the 1- to 8-year series. Currently, we are helping local school

  14. Inter-annual Variability of Biomass Burning Aerosol Optical Depth in Southern Amazonia, and the Impact of These Aerosols on the Diurnal Cycle of Solar Flux Reduction

    NASA Astrophysics Data System (ADS)

    Eck, T. F.; Holben, B. N.; Schafer, J. S.; Artaxo, P.; Yamasoe, M. A.; Procopio, A. S.; Prins, E. M.; Feltz, J. M.; Smirnov, A.; Dubovik, O.; Reid, J. S.

    2002-12-01

    The inter-annual variability of the magnitude of biomass burning in southern Amazonia has been relatively large over the last decade. The extent of the burning in the latter half of a given dry season (July-October) depends largely on the rainfall amount and timing, with drought years exhibiting many more fires and smoke than average. Additionally, new regulations aimed at controlling burning may also affect inter-annual variability. We present measurements of aerosol optical depth (AOD) from biomass burning smoke as measured by AERONET sites in Rondonia and Mato Grosso from 1993-2002. These AOD measurements are shown to follow similar inter-annual variability as the fire counts determined by the multi-spectral radiance measurements obtained with GOES-8. However, the AOD at these sites exhibit relatively little diurnal variation despite a very large diurnal cycle in satellite detected fire counts. In order to quantify the changes in the diurnal cycle of solar flux reduction as a result of aerosol attenuation at the peak of the burning season, we model the diurnal cycle of total shortwave (SW; 300-4000 nm), photosynthetically active radiation (PAR; 400-700 nm), and Ultraviolet- A (UVA; 320-400 nm) fluxes in mid-September using the AERONET monthly average AOD measurements (AOD(550 nm) = 1.11). These average diurnal cycle flux reductions show significant temporal delays in the morning for equivalent flux levels in all three spectral bands, of ~50 min to 2 hr 15 min at mid-morning (midpoint between sunrise and solar noon). The largest time delays in flux occur in the UVA band and the smallest in the total SW broadband due to a rapid decrease in AOD as wavelength increases for the accumulation mode smoke aerosols. The time delays in solar flux have implications for possible delay of the onset of cumulus convection, the shortening of the photo-period when plants photosynthesize, and reduced time interval for UVA fluxes which may have implications for photochemical

  15. From patterns to process: effects of Land use/cover on the biogeochemistry of surface waters in Western Amazonia (Rond“nia, Brazil)

    NASA Astrophysics Data System (ADS)

    Ballester, V. M.; Richey, J. E.; Krusche, A. V.; Victoria, D. D.; Victoria, R. L.; Deegan, L. A.; Niell, C.

    2002-12-01

    To comprehend how land use change is affecting river biogeochemistry, it is necessary to identify the structural and functional alterations of the landscape configuration and composition, key attributes to understand how river biogeochemical signals are generated, maintained and altered by human intervention. Here we present the results of an integrated landscape analysis of the meso-scale Ji-Parana river basin (western Amazonia) based on landscape patterns, including soil properties, river network, topography and land use/cover. Our main objective was to understand what are the relationships between basin attributes and surface water chemistry. In terms of the consequences for river biogeochemistry, the heterogeneous spatial distribution of deforestation and soil properties along the basin translate into different signals. Sectors of the river with poorer soils also had waters with lower ionic content, whereas richer soils relate to waters with higher concentrations of salts. The percentage of the basin area covered by pasture was a good predictor for the concentrations of K+, Ca2+, Mg2+, electrical conductivity and pCO2. These results could be an indication that not only the soils cation content are determinants of river water quality, but also, that there are intensive cation losses by soil erosion resulting from inadequate pasture management. Concentrations of these elements increased constantly as the river drains areas dominated mainly by pasture. The statistical analysis shows that pasture cover explains 99% of the variance observed in theconcentrations of these elements in the river. The highest values were found at the central part of the basin, where pasture areas are maximum. Based on the patterns of pasture establishment observed in this study it is not likely that deforestation will occur in the head waters of the basin, due to soils characteristics of that region. Environmental concern about deforestation should focus, instead, on the lower reaches of

  16. Systematics and biogeography of the Automolus infuscatus complex (Aves; Furnariidae): Cryptic diversity reveals western Amazonia as the origin of a transcontinental radiation.

    PubMed

    Schultz, Eduardo D; Burney, Curtis W; Brumfield, Robb T; Polo, Erico M; Cracraft, Joel; Ribas, Camila C

    2017-02-01

    A revision of the avian Neotropical genus Automolus and the Furnariidae family points to the paraphyly of A. infuscatus and reveals a species complex comprising A. infuscatus, A. ochrolaemus, A. paraensis, A. leucophthalmus, A. lammi and A. subulatus, the latter historically classified in the genus Hyloctistes. Detailed knowledge of the taxonomy, geographic distribution, phylogenetic relationship and divergence times of a taxon allows exploration of its evolutionary history and the testing of different scenarios of diversification. In this context, we studied the A. infuscatus complex using molecular data in order to unveil its cryptic diversity and reveal its evolutionary history. For that we sequenced two mitochondrial (ND2 and cytb) and three nuclear markers (G3PDH, ACO, Fib7) for 302 individuals belonging to all species in the complex and most described subspecies. Our analysis supports the paraphyly of A. infuscatus, indicating the existence of at least two distinct clades not closely related. The remaining species were all recovered as monophyletic. Notwithstanding, a well-structured intraspecific diversity was found with 19 lineages suggesting substantial cryptic diversity within the described species. A. subulatus was recovered within the complex, corroborating its position inside the genus. In spite of the high congruence between distributions of different lineages, with several sister lineages currently separated by the same barriers, the temporal incongruence between divergences over the same barriers reveals a complex evolutionary history. While older events might be related to the emergence of barriers such as the Andes and major Amazonian rivers, younger events suggest dispersal after the consolidation of those barriers. Our analysis suggests that the complex had its origin around 6million years (Ma) and inhabited Western Amazonia in Late Miocene-Early Pliocene. Considering the riparian habit of species in its sister clade, the rise and early

  17. Soil physical restrictions and hydrology regulate stand age and wood biomass turnover rates of Purus-Madeira interfluvial wetlands in Amazonia

    NASA Astrophysics Data System (ADS)

    Cintra, B. B. L.; Schietti, J.; Emillio, T.; Martins, D.; Moulatlet, G.; Souza, P.; Levis, C.; Quesada, C. A.; Schöngart, J.

    2013-11-01

    In Amazonia, wetlands constitute about 30% of its entire basin, of which ancient fluvial terraces located in vast interfluvial regions cover a large portion. Although the increased number of permanent plots in the recent years has contributed to improved understanding of regional variation in forest dynamics across the Amazon Basin, the functioning of large lowland interfluvial wetlands remain poorly understood. Here we present the first field-based estimate for tree ages, wood biomass productivity and biomass turnover rates for eight 1 ha plots in wetland and non-flooded forests distributed along the BR-319 Highway along a distance of about 600 km crossing the Purus-Madeira rivers interfluvial region in central-southwestern Amazon Basin. We estimate stand age, wood biomass productivity and biomass turnover rates combining tree-ring data and an allometric equation based on diameter, tree height and wood density and relate these structural parameters to physical soil and hydrological restrictions. Wood biomass and productivity varied twofold among the plots, with wood biomass stocks ranging between 138-294 Mg ha-1 and productivity varying between 3.4-6.6 Mg ha-1 yr-1. Soil effective depth, topography, structure and mainly soil water saturation significantly affected stand age (64-103 yr) and forest dynamics in terms of annual biomass turnover rates (2.0-3.2%). On harsher soils characterized by a poor structure, low effective depth and high water saturation, biomass turnover rates were increased and forests stands were younger compared to well-drained sites. We suggest that soil constraints, especially soil water saturation, limit the development of the stand structure, resulting in forests with younger stand ages and higher biomass turnover rates compared to forests growing on well-drained soils. We do not find, however, any relation between physical soil restrictions or hydrology and wood biomass productivity, but there is a trend of increasing wood biomass

  18. Inferences of Present and Past Changes at Isolated Enclaves and Matrix of Savannas by Carbon Isotopes in a Transitional Forest-Savanna Area in Northern Amazonia

    NASA Astrophysics Data System (ADS)

    Couto-Santos, F. R.; Luizao, F. J.; Camargo, P. B.

    2013-12-01

    The evolutionary history of savannas influenced by short term climate cycles, during the Quaternary Period, could prompt variations in forest cover often related to movements of the forest-savanna boundary. In this study we investigated current and past changes in the structure of vegetation and the origins of savannas of different natures in a biogeographically and climatic transitional forest-savanna area in northern Amazonia. Variations in the isotopic composition of soil organic matter (δ13C) from surface soils (0-10 cm) along forest-savanna boundaries, detected by a sigmoidal non-linear function, were used to identify current changes in vegetation, while past changes were inferred by discontinuities in the evolution of δ13C with soil depth using piecewise regression associated with radiocarbon dating (14C). By comparing small isolated savanna enclaves inside a strictly protected nature reserve (ESEC Maracá) with its outskirts unprotected continuous savanna matrix, we found that origins and the patterns of dynamics were distinct between these areas and did not respond in the same way to climate change and fire events, either in the last decades or during the Holocene. The stability of the present boundaries of the surrounding savanna matrix reflects the resilience of the transitional forests under a recent intensified fire regime and favorable climate, while the deep forest soil isotopic signal indicated a forest shrinkage of at least 70 m occurring since its origin in early Holocene until 780 years BP associated with a climate drier than the current one. Contrarily, the protected enclaves inside ESEC Maracá, remained stable since the middle Holocene, suggesting a non-anthropogenic origin related to soil edaphic conditions, but with recent dynamics of advancing forest by 8 m century-1 favored by current climate and lacking fire events. A detailed understanding of the origins of savannas of distinct natures and the way they are affected by climate and fire

  19. Saving Salmon Through Advances in Fluvial Remote Sensing: Applying the Optimal Band Ratio Analysis (OBRA) for Bathymetric Mapping of Over 250 km of River Channel and Habitat Classification

    NASA Astrophysics Data System (ADS)

    Richardson, R.; Legleiter, C. J.; Harrison, L.

    2015-12-01

    Salmonids are threatened with extinction across the world from the fragmentation of riverine ecosystems from dams and diversions. In California, efforts to expand the range of spawnable habitat for native salmon by transporting fish around reservoirs is a potentially species saving idea. But, strong scientific evidence of the amount of high quality habitat is required to make these difficult management decisions. Remote sensing has long been used in fluvial settings to identify physical parameters that drive the quality of aquatic habitat; however, the true strength of remote sensing to cover large spatial extents has not been applied with the resolution that is relevant to salmonids. This project utilizes hyperspectral data of over 250 km of the Tuolumne and Merced Rivers to extract depth and bed slope from the wetted channel and NIR LiDAR for the surrounding topography. The Optimal Band Ratio Analysis (OBRA) has proven as an effective tool to create bathymetric maps of river channels in ideal settings with clear water, high amounts of bottom reflectance, and less than 3 meters deep over short distances. Results from this study show that OBRA can be applied over larger riverscapes at high resolutions (0.5 m). The depth and bed slope estimations are used to classify habitat units that are crucial to quantifying the quality and amount of habitat in these river that once produced large populations of native salmonids. As more managers look to expand habitat for these threatened species the tools developed here will be cost effective over the large extents that salmon migrate to spawn.

  20. New tools and insights to assist with the molecular identification of Simulium guianense s.l., main Onchocerca volvulus vector within the highland areas of the Amazonia onchocerciasis focus.

    PubMed

    Crainey, James L; Mattos-Glória, Aline; Hamada, Neusa; Luz, Sérgio L B

    2014-03-01

    Following the success of the Onchocerciasis Elimination Programme for the Americas (OEPA), there is now just one Latin American onchocerciasis focus where onchocerciasis transmission is described as 'on-going:' the Amazonia Onchocerciasis focus. In the hyperendemic highland areas of the Amazonia focus, Simulium guianense s.l. Wise are the most important vectors of the disease. Populations of S. guianense s.l. are, however, known to vary in their cytogenetics and in a range of behaviours, including in their biting habits. In the hypoendemic lowland areas of the Amazonia focus, for example, S. guianense s.l. are generally regarded as zoophilic and consequently unimportant to disease transmission. Robust tools, to discriminate among various populations of S. guianense s.l. have, however, not yet been developed. In the work reported here, we have assessed the utility of a ribosomal DNA sequence fragment spanning the nuclear ribosomal ITS-1, ITS-2 and 5.8S sequence regions and a ∼850 nucleotide portion of the mitochondrial cytochrome oxidase gene (CO1) for species-level identification and for resolving the within species substructuring. We report here how we have generated 78 CO1 sequences from a rich set of both zoophilic and anthropophilic populations of S. guianense s.l. that were collected from eight sites that are broadly distributed across Brazil. Consistent with previous findings, our analysis supports the genetic isolation of Simulium litobranchium from S. guianense s.l. In contrast with previous findings, however, our results did not provide support for the divergence of the two species prior to the radiation of S. guianense s.l. In our analysis of the S. guianense s.l. ribosomal DNA sequence trace files we generated, we provide clear evidence of multiple within-specimen single nucleotide polymorphisms and indels suggesting that S. guianense s.l. ribosomal DNA is not a good target for conventional DNA barcoding. This is the first report of S. guianense s

  1. Na Cauda do Cometa

    NASA Astrophysics Data System (ADS)

    Voelzke, M. R.

    2009-01-01

    Quando viam um cometa, os antigos gregos imaginavam uma estrela com uma vasta cabeleira. Não à toa, a palavra deriva do termo koma, que significa cabelo. Constituídos por fragmentos de gelo e gases, os cometas possuem um núcleo sólido, que pode ter vários quilômetros de diâmetro, e uma cauda que sempre aponta na direção contrária ao Sol, devido aos ventos solares. Graças à aparência de pontos luminosos em movimento (ao contrário de outros astros, que parecem estáticos), esses corpos celestes foram interpretados por diferentes povos com muito misticismo, inspirando mitos tanto de boas-novas como de maus presságios. Conheça algumas dessas histórias:

  2. Strengthening Adaptation to Extreme Climate Events in Southwestern Amazonia: an Example from the Trinational Acre River Basin in the Madre de Dios/Peru - Acre/Brazil - Pando/Bolivia (MAP) Region.

    NASA Astrophysics Data System (ADS)

    Brown, I. F.

    2015-12-01

    Southwestern Amazonia, where Bolivia, Brazil and Peru meet, faces numerous challenges to the sustainable utilization of land and water resources as the region experiences rapid population and economic growth, expanding agriculture, transportation and energy sectors, along with frequent flooding and droughts. It is also predicted to be one of the most susceptible areas for climate change in the coming decade. The Acre River Basin, one of the few trinational basins in Amazonia, lies at the center of the Madre de Dios Region (Peru), Acre State (Brazil) and Pando Department (Bolivia) or MAP Region. It covers approximately 7,500 km2 and its inhabitants range from indigenous groups avoiding contact with industrial society to more than 60,000 dwellers of a binational urban center. The basin incorporates most the challenges facing the region and this paper discusses steps underway to address the basin's vulnerability to climate-related threats. A trinational group of professionals used GIS databases and local knowledge to classify these threats and possible societal responses. To prioritize threats and to propose responses, this group adapted a method proposed by the Queensland Climate Change Centre of Excellence of Australia to develop climate risk matrices for assessing impacts, adaptation, risk and vulnerability. The three priority climate variables were prolonged and more frequent droughts, more intense flooding, and more days with temperatures > 35oC. The final matrix proposed two areas of concentration - 1) Reduce the vulnerability of communities to hydro-meteorological extreme events and 2) Protect and restore ecosystems that maintain critical water-related resources with actions in public policy, capacity-building, and immediate activities. These results are being incorporated into the Amazon Project of the Global Environment Fund of the United Nations Environment Program, administered by the Amazon Cooperation Treaty Organization (ACTO).

  3. Na+ coordination at the Na2 site of the Na+/I− symporter

    PubMed Central

    Ferrandino, Giuseppe; Nicola, Juan Pablo; Sánchez, Yuly E.; Echeverria, Ignacia; Liu, Yunlong; Amzel, L. Mario; Carrasco, Nancy

    2016-01-01

    The sodium/iodide symporter (NIS) mediates active I− transport in the thyroid—the first step in thyroid hormone biosynthesis—with a 2 Na+: 1 I− stoichiometry. The two Na+ binding sites (Na1 and Na2) and the I− binding site interact allosterically: when Na+ binds to a Na+ site, the affinity of NIS for the other Na+ and for I− increases significantly. In all Na+-dependent transporters with the same fold as NIS, the side chains of two residues, S353 and T354 (NIS numbering), were identified as the Na+ ligands at Na2. To understand the cooperativity between the substrates, we investigated the coordination at the Na2 site. We determined that four other residues—S66, D191, Q194, and Q263—are also involved in Na+ coordination at this site. Experiments in whole cells demonstrated that these four residues participate in transport by NIS: mutations at these positions result in proteins that, although expressed at the plasma membrane, transport little or no I−. These residues are conserved throughout the entire SLC5 family, to which NIS belongs, suggesting that they serve a similar function in the other transporters. Our findings also suggest that the increase in affinity that each site displays when an ion binds to another site may result from changes in the dynamics of the transporter. These mechanistic insights deepen our understanding not only of NIS but also of other transporters, including many that, like NIS, are of great medical relevance. PMID:27562170

  4. A novel methodology using MODIS and CERES for assessing the daily radiative forcing of smoke aerosols in large scale over the Amazonia

    NASA Astrophysics Data System (ADS)

    Sena, E. T.; Artaxo, P.

    2014-12-01

    A new methodology was developed for obtaining daily retrievals of the direct radiative forcing of aerosols (24h-DARF) at the top of the atmosphere (TOA) using satellite remote sensing. For that, simultaneous CERES (Clouds and Earth's Radiant Energy System) shortwave flux at the top of the atmosphere (TOA) and MODIS (Moderate Resolution Spectroradiometer) aerosol optical depth (AOD) retrievals were used. This methodology is applied over a large region of Brazilian Amazonia. We focused our studies on the peak of the biomass burning season (August to September) from 2000 to 2009 to analyse the impact of forest smoke on the radiation balance. To assess the spatial distribution of the DARF, background scenes without biomass burning impacts, were defined as scenes with MODIS AOD < 0.1. The fluxes at the TOA retrieved by CERES for those clean conditions (Fcl) were estimated as a function of the illumination geometry (θ0) for each 0.5° × 0.5° grid cell. The instantaneous DARF was obtained as the difference between clean Fcl (θ0) and the polluted mean flux at the TOA measured by CERES in each cell (Fpol (θ0)). The radiative transfer code SBDART (Santa Barbara DISORT Radiative Transfer model) was used to expand instantaneous DARFs to 24 h averages. With this methodology it is possible to assess the DARF both at large scale and at high temporal resolution. This new methodology also showed to be more robust, because it considerably reduces statistical sources of uncertainties in the estimates of the DARF, when compared to previous assessments of the DARF using satellite remote sensing. The spatial distribution of the 24h-DARF shows that, for some cases, the mean 24h-DARF presents local values as high as -30 W m-2. The temporal variability of the 24h-DARF along the biomass burning season was also studied and showed large intraseasonal and interannual variability. In an attempt to validate the radiative forcing obtained in this work using CERES and MODIS, those results

  5. Solidification of NaCl-NaF eutectic in space

    NASA Technical Reports Server (NTRS)

    Yue, A. S.; Yu, J. G.

    1974-01-01

    Continuous and discontinuous NaF fibers, embedded in a NaCl matrix, have been produced in space and on earth, respectively. The production of continuous fibers in a eutectic mixture was attributed to the absence of convection current in the liquid during solidification in space. Image transmission and optical transmittance measurements of transverse sections of the space-grown and earth-grown ingots were made with a light microscope and a spectrometer. It was found that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of NaF fibers along the ingot axis.

  6. Extractive reserves in Brazilian Amazonia

    SciTech Connect

    Fearnside, P.M )

    1989-06-01

    In 1985 an opportunity arose for maintaining tracts of Amazonian forest under sustainable use. Brazil's National Council of Rubber Tappers and the Rural Worker's Union proposed the creation of a set of reserves of a new type, called extractive reserves. The first six are being established in one of the Brazilian states most threatened by deforestatation. The creation of extractive reserves grants legal protection to forest land traditionally used by rubber tappers, Brazil-nut gatherers, and other extractivists. The term extrativismo (extractivism) in Brazil refers to removing nontimber forest products, such as latex, resins, and nuts, without felling the trees. Approximately 30 products are collected for commercial sale. Many more types of forest materials are gathered, for example as food and medicines, for the extractivists' own use. The reserve proposal is attractive for several reasons related to social problems. It allows the rubber tappers to continue their livelihood rather than be expelled by deforestation. However, it is unlikely that sufficient land will be set aside as extractive reserves to employ all the tappers. Displaced rubber tappers already swell the ranks of urban slum dwellers in Brazil's Amazonian cities, and they have become refugees to continue their profession in the forests of neighboring countries, such as Bolivia.

  7. Andean settlers rush for Amazonia.

    PubMed

    Serra-vega, J

    1990-01-01

    Governments of Andean countries (Peru, Bolivia, Colombia, Ecuador, and Venezuela) have encouraged migration to the Amazon Basin, which has contributed to its destruction. Population pressure, landlessness, and poverty are the inducements to migrate. Efforts to populate the Amazon forest were begun as early as 1964 in Peru without international notice. By 1980, logging was allowed in Peru, and Brazil considered colonization of the Amazon essential to national sovereignty. By 1986, outside of Lima, Peru, a development project originally funded by the World Bank, the InterAmerican Development Bank, and the US, resulted in conflicts between settlers and Indians, in loggers indiscriminately cutting, and in farmers using slash and burn techniques to clear forests. Elsewhere the Peruvian Amazon, in San Ignacio, the population was growing by 5.5%/year. The jungle road that had been started but never completed, Carretera Marginal, destroyed 5 million hectares of primary forest, and much of the 600,000 hectares of arable land gained by the road suffered from inappropriate farming practices which caused massive erosion and laterization of the soils. Food crop production declined, and production of coca for cocaine increased. Coca crops are controlled by the Shining Path guerrillas, who are trying to overthrow the Peruvian government. Devastation of Ecuador around Lago Agrio continues. In Colombia, east of Bogota, forests have disappeared and hills have eroded and silted up rivers and dams. The Andean piedmont in Bolivia has also been devastated by loggers and by slash and burn farming. Southeastern Bolivian forests have been cleared for soya bean cultivation on poor soils. Social and economic crises propel people into the remaining forests. The solution is to ease foreign debt, transfer appropriate technology at affordable prices, refuse to finance destructive development, and help to educate and train scientific researchers. Family planning services are also urgently needed. Basic facts on population, biodiversity, the greenhouse effect, deforestation, roads, iron, gold, and Indians is provided.

  8. Na+ recirculation and isosmotic transport.

    PubMed

    Larsen, E H; Møbjerg, N

    2006-01-01

    The Na(+) recirculation theory for solute-coupled fluid absorption is an expansion of the local osmosis concept introduced by Curran and analyzed by Diamond & Bossert. Based on studies on small intestine the theory assumes that the observed recirculation of Na(+) serves regulation of the osmolarity of the absorbate. Mathematical modeling reproducing bioelectric and hydrosmotic properties of small intestine and proximal tubule, respectively, predicts a significant range of observations such as isosmotic transport, hyposmotic transport, solvent drag, anomalous solvent drag, the residual hydraulic permeability in proximal tubule of AQP1 (-/-) mice, and the inverse relationship between hydraulic permeability and the concentration difference needed to reverse transepithelial water flow. The model reproduces the volume responses of cells and lateral intercellular space (lis) following replacement of luminal NaCl by sucrose as well as the linear dependence of volume absorption on luminal NaCl concentration. Analysis of solvent drag on Na(+) in tight junctions provides explanation for the surprisingly high metabolic efficiency of Na(+) reabsorption. The model predicts and explains low metabolic efficiency in diluted external baths. Hyperosmolarity of lis is governed by the hydraulic permeability of the apical plasma membrane and tight junction with 6-7 mOsm in small intestine and < or = 1 mOsm in proximal tubule. Truly isosmotic transport demands a Na(+) recirculation of 50-70% in small intestine but might be barely measurable in proximal tubule. The model fails to reproduce a certain type of observations: The reduced volume absorption at transepithelial osmotic equilibrium in AQP1 knockout mice, and the stimulated water absorption by gallbladder in diluted external solutions. Thus, it indicates cellular regulation of apical Na(+) uptake, which is not included in the mathematical treatment.

  9. Astrocytes generate Na+-mediated metabolic waves.

    PubMed

    Bernardinelli, Yann; Magistretti, Pierre J; Chatton, Jean-Yves

    2004-10-12

    Glutamate-evoked Na+ increase in astrocytes has been identified as a signal coupling synaptic activity to glucose consumption. Astrocytes participate in multicellular signaling by transmitting intercellular Ca2+ waves. Here we show that intercellular Na+ waves are also evoked by activation of single cultured cortical mouse astrocytes in parallel with Ca2+ waves; however, there are spatial and temporal differences. Indeed, maneuvers that inhibit Ca2+ waves also inhibit Na+ waves; however, inhibition of the Na+/glutamate cotransporters or enzymatic degradation of extracellular glutamate selectively inhibit the Na+ wave. Thus, glutamate released by a Ca2+ wave-dependent mechanism is taken up by the Na+/glutamate cotransporters, resulting in a regenerative propagation of cytosolic Na+ increases. The Na+ wave gives rise to a spatially correlated increase in glucose uptake, which is prevented by glutamate transporter inhibition. Therefore, astrocytes appear to function as a network for concerted neurometabolic coupling through the generation of intercellular Na+ and metabolic waves.

  10. Europlanet NA2 Science Networking

    NASA Astrophysics Data System (ADS)

    Harri, Ari-Matti; Szego, Karoly; Genzer, Maria; Schmidt, Walter; Krupp, Norbert; Lammer, Helmut; Kallio, Esa; Haukka, Harri

    2013-04-01

    Europlanet RI / NA2 Science Networking [1] focused on determining the major goals of current and future European planetary science, relating them to the Research Infrastructure that the Europlanet RI project [2] developed, and placing them in a more global context. NA2 also enhanced the ability of European planetary scientists to participate on the global scene with their own agenda-setting projects and ideas. The Networking Activity NA2 included five working groups, aimed at identifying key science issues and producing reference books on major science themes that will bridge the gap between the results of present and past missions and the scientific preparation of the future ones. Within the Europlanet RI project (2009-2012) the NA2 and NA2-WGs organized thematic workshops, an expert exchange program and training groups to improve the scientific impact of this Infrastructure. The principal tasks addressed by NA2 were: • Science activities in support to the optimal use of data from past and present space missions, involving the broad planetary science community beyond the "space club" • Science activities in support to the preparation of future planetary missions: Earth-based preparatory observations, laboratory studies, R&D on advanced instrumentation and exploration technologies for the future, theory and modeling etc. • Develop scientific activities, joint publications, dedicated meetings, tools and services, education activities, engaging the public and industries • Update science themes and addressing the two main scientific objectives • Prepare and support workshops of the International Space Science Institute (ISSI) in Bern and • Support Trans National Activities (TNAs), Joined Research Activities (JRAs) and the Integrated and Distributed Information Service (IDIS) of the Europlanet project These tasks were achieved by WG workshops organized by the NA2 working groups, by ISSI workshops and by an Expert Exchange Program. There were 17 official WG

  11. Sodium iron hexacyanoferrate with high Na content as a Na-rich cathode material for Na-ion batteries

    DOE PAGES

    You, Ya; Yu, Xi -Qian; Yin, Ya -Xia; ...

    2014-10-27

    Owing to the worldwide abundance and low-cost of Na, room-temperature Na-ion batteries are emerging as attractive energy storage systems for large-scale grids. Increasing the Na content in cathode material is one of the effective ways to achieve high energy density. Prussian blue and its analogues (PBAs) are promising Na-rich cathode materials since they can theoretically store two Na ions per formula. However, increasing the Na content in PBAs cathode materials is a big challenge in the current. Here we show that sodium iron hexacyanoferrate with high Na content could be obtained by simply controlling the reducing agent and reaction atmospheremore » during synthesis. The Na content can reach as high as 1.63 per formula, which is the highest value for sodium iron hexacyanoferrate. This Na-rich sodium iron hexacyanoferrate demonstrates a high specific capacity of 150 mA h g-1 and remarkable cycling performance with 90% capacity retention after 200 cycles. Furthermore, the Na intercalation/de-intercalation mechanism is systematically studied by in situ Raman, X-ray diffraction and X-ray absorption spectroscopy analysis for the first time. As a result, the Na-rich sodium iron hexacyanoferrate could function as a plenteous Na reservoir and has great potential as a cathode material toward practical Na-ion batteries.« less

  12. Sodium iron hexacyanoferrate with high Na content as a Na-rich cathode material for Na-ion batteries

    SciTech Connect

    You, Ya; Yu, Xi -Qian; Yin, Ya -Xia; Nam, Kyung -Wan; Guo, Yu -Guo

    2014-10-27

    Owing to the worldwide abundance and low-cost of Na, room-temperature Na-ion batteries are emerging as attractive energy storage systems for large-scale grids. Increasing the Na content in cathode material is one of the effective ways to achieve high energy density. Prussian blue and its analogues (PBAs) are promising Na-rich cathode materials since they can theoretically store two Na ions per formula. However, increasing the Na content in PBAs cathode materials is a big challenge in the current. Here we show that sodium iron hexacyanoferrate with high Na content could be obtained by simply controlling the reducing agent and reaction atmosphere during synthesis. The Na content can reach as high as 1.63 per formula, which is the highest value for sodium iron hexacyanoferrate. This Na-rich sodium iron hexacyanoferrate demonstrates a high specific capacity of 150 mA h g-1 and remarkable cycling performance with 90% capacity retention after 200 cycles. Furthermore, the Na intercalation/de-intercalation mechanism is systematically studied by in situ Raman, X-ray diffraction and X-ray absorption spectroscopy analysis for the first time. As a result, the Na-rich sodium iron hexacyanoferrate could function as a plenteous Na reservoir and has great potential as a cathode material toward practical Na-ion batteries.

  13. Ionic regulation of Na absorption in proximal colon: cation inhibition of electroneutral Na absorption

    SciTech Connect

    Sellin, J.H.; De Soignie, R.

    1987-01-01

    Active Na absorption (J/sub net//sup NA/) in rabbit proximal colon in vitro is paradoxically stimulated as (Na) in the bathing media is lowered with constant osmolarity. J/sub m..-->..s//sup Na/ increases almost linearly from 0 to 50 mM (Na)/sub 0/ but then plateaus and actually decreases from 50 to 140 mM (Na)/sub 0/, consistent with inhibition of an active transport process. Both lithium and Na are equally effective inhibitors of J/sub net//sup Na/, whereas choline and mannitol do not block the high rate of J/sub net//sup Na/ observed in decreased (Na)/sub 0/. Either gluconate or proprionate replacement of Cl inhibits J/sub net//sup Na/. J/sub net//sup Na/ at lowered (Na)/sub 0/ is electrically silent and is accompanied by increased Cl absorption; it is inhibited by 10/sup -3/ M amiloride and 10/sup -3/ theophylline but not by 10/sup -4/ M bumetanide. Epinephrine is equally effective at stimulating Na absorption at 50 and 140 mM (Na). Na gradient experiments are consistent with a predominantly serosal effect of the decreased (Na)/sub 0/. These results suggest that 1) Na absorption in rabbit proximal colon in vitro is stimulated by decreased (Na); 2) the effect is cation specific, both Na and Li blocking the stimulatory effect; 3) the transport is mediated by Na-H exchange and is Cl dependent but 4) is under different regulatory mechanisms than the epinephrine-sensitive Na-Cl cotransport previously described in proximal colon. Under the appropriate conditions, proximal colon absorbs Na extremely efficiently. Na-H exchange in this epithelium is cation inhibitable, either directly or by a secondary regulatory process.

  14. Deliquescence of NaCl-NaNO3 and KNO3-NaNO3 Salt Mixtures at 90C

    SciTech Connect

    Carroll, S; Craig, L; Wolery, T

    2003-12-29

    We conducted reversed deliquescence experiments in saturated NaCl-NaNO3-H2O and KNO{sub 3}-NaNO{sub 3}-H{sub 2}O systems at 90 C to determine relative humidity and solution composition. NaCl, NaNO{sub 3}, and KNO{sub 3} represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV, USA. Model predictions agree with experimental results for the NaCl-NaNO{sub 3}-H{sub 2}O system, but underestimate relative humidity by as much as 8% and solution composition by as much as 50% in the KNO{sub 3}-NaNO{sub 3}-H{sub 2}O system.

  15. Na+ Tolerance and Na+ Transport in Higher Plants

    PubMed Central

    TESTER, MARK; DAVENPORT, ROMOLA

    2003-01-01

    Tolerance to high soil [Na+] involves processes in many different parts of the plant, and is manifested in a wide range of specializations at disparate levels of organization, such as gross morphology, membrane transport, biochemistry and gene transcription. Multiple adaptations to high [Na+] operate concurrently within a particular plant, and mechanisms of tolerance show large taxonomic variation. These mechanisms can occur in all cells within the plant, or can occur in specific cell types, reflecting adaptations at two major levels of organization: those that confer tolerance to individual cells, and those that contribute to tolerance not of cells per se, but of the whole plant. Salt‐tolerant cells can contribute to salt tolerance of plants; but we suggest that equally important in a wide range of conditions are processes involving the management of Na+ movements within the plant. These require specific cell types in specific locations within the plant catalysing transport in a coordinated manner. For further understanding of whole plant tolerance, we require more knowledge of cell‐specific transport processes and the consequences of manipulation of transporters and signalling elements in specific cell types. PMID:12646496

  16. Conversion and Distribution of Lead and Tin in NaOH-NaNO3 Fusion Process

    NASA Astrophysics Data System (ADS)

    Liu, Jingxin; Guo, Xueyi

    2017-04-01

    Oxidizing alkali fusion process has been studied to extract amphoteric metals. Transformation and distribution behaviors of typical amphoteric metals Pb and Sn in the NaOH-NaNO3 fusion process are systemically studied by theoretical analysis and experimental verification done in this work. Functions of NaOH and NaNO3 in the fusion process were also investigated. The results show the fused products, Na2PbO3 and Na2SnO3, are captured in the flux, and Na2PbO4 is speculated to reduce to Pb(II) in the following leaching process. By measuring solubility data of NaOH-Na2SnO3-PbO-H2O system, a strategy of crystallization is proposed to separate Sn with Pb in concentrated alkaline solution, and slice Na2Sn(OH)6 is obtained as a product.

  17. Conversion and Distribution of Lead and Tin in NaOH-NaNO3 Fusion Process

    NASA Astrophysics Data System (ADS)

    Liu, Jingxin; Guo, Xueyi

    2016-12-01

    Oxidizing alkali fusion process has been studied to extract amphoteric metals. Transformation and distribution behaviors of typical amphoteric metals Pb and Sn in the NaOH-NaNO3 fusion process are systemically studied by theoretical analysis and experimental verification done in this work. Functions of NaOH and NaNO3 in the fusion process were also investigated. The results show the fused products, Na2PbO3 and Na2SnO3, are captured in the flux, and Na2PbO4 is speculated to reduce to Pb(II) in the following leaching process. By measuring solubility data of NaOH-Na2SnO3-PbO-H2O system, a strategy of crystallization is proposed to separate Sn with Pb in concentrated alkaline solution, and slice Na2Sn(OH)6 is obtained as a product.

  18. A medium-spatial scale distribution pattern of Pseudoscorpionida (Arachnida) in a gradient of topography (altitude and inclination), soil factors, and litter in a central Amazonia forest reserve, Brazil.

    PubMed

    Aguiar, N O; Gualberto, T L; Franklin, E

    2006-08-01

    In Amazonia, nothing is known about the distribution of the invertebrates on a medium-spatial scale pattern. In a trail system of 64 km2 at Ducke Reserve, we sampled 72 transects using the hand-sorting method and Berlese-Tullgren extraction. The reserve possesses ecosystems of "terra-firme" forest and the trail system represents a gradient of topographic soil factors and vegetation, avoiding categorizations. Considering the abundance and diversity of Pseudoscorpionida, we investigated the relation of the community to environmental factors tested (topography, clay percentage, litter, and soil pH), to the two major drainage basins of the reserve, and if these invertebrates can be used as biological indicators to monitor changes. We registered two species for the first time in the reserve, increasing the known diversity to 17 species. The lack of correlation with the predictor variables and the large home range, indicate that pseudoscorpions are not good biological indicators in the reserve. As the eastern and western watersheds are not separate management units for the community, our results show that they are generalist predators. In spite of our results and lack of knowledge concerning their biology, life history and taxonomy, pseudoscorpions are cosmopolitan and easy to find and measure. Compared with previous studies in the reserve, they have a consistent pattern of abundance and diversity throughout the years showing the stability of the community which can be checked mainly by comparison with environmental changes that would occur in the reserve. An investigation on a medium-spatial scale pattern and over a long-term period including other habitats, and also other predictor variables, like humidity, the structure of the vegetation and canopy closure, will be necessary to reinforce the observed tendencies.

  19. Performance of Two Cloud-Radiation Parameterization Schemes in the Finite Volume General Circulation Model for Anomalously Wet May and June 2003 Over the Continental United States and Amazonia

    NASA Technical Reports Server (NTRS)

    Sud, Y. C.; Mocko, David M.; Lin, S. J.

    2006-01-01

    An objective assessment of the impact of a new cloud scheme, called Microphysics of Clouds with Relaxed Arakawa-Schubert Scheme (McRAS) (together with its radiation modules), on the finite volume general circulation model (fvGCM) was made with a set of ensemble forecasts that invoke performance evaluation over both weather and climate timescales. The performance of McRAS (and its radiation modules) was compared with that of the National Center for Atmospheric Research Community Climate Model (NCAR CCM3) cloud scheme (with its NCAR physics radiation). We specifically chose the boreal summer months of May and June 2003, which were characterized by an anomalously wet eastern half of the continental United States as well as northern regions of Amazonia. The evaluation employed an ensemble of 70 daily 10-day forecasts covering the 61 days of the study period. Each forecast was started from the analyzed initial state of the atmosphere and spun-up soil moisture from the first-day forecasts with the model. Monthly statistics of these forecasts with up to 10-day lead time provided a robust estimate of the behavior of the simulated monthly rainfall anomalies. Patterns of simulated versus observed rainfall, 500-hPa heights, and top-of-the-atmosphere net radiation were recast into regional anomaly correlations. The correlations were compared among the simulations with each of the schemes. The results show that fvGCM with McRAS and its radiation package performed discernibly better than the original fvGCM with CCM3 cloud physics plus its radiation package. The McRAS cloud scheme also showed a reasonably positive response to the observed sea surface temperature on mean monthly rainfall fields at different time leads. This analysis represents a method for helpful systematic evaluation prior to selection of a new scheme in a global model.

  20. Monitoring the spatial and temporal dynamics of the Brazilian Cerrado physiognomies with spectral vegetation indices: An assessment within the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA)

    NASA Astrophysics Data System (ADS)

    Ferreira, Laerte Guimaraes, Junior

    The large extension and diversity of the Cerrado vegetative cover, the second largest biome in South America, has a strong impact on regional, and possibly global, energy, water, and carbon balances. Nevertheless, as a major farming frontier in Brazil, it is estimated that about 40% of the Cerrado land cover has already been converted into cultivated pastures, field crops, urban development, and degraded areas. Despite this aggressive pace of land conversion, there have been few investigations on the operational utilization of remote sensing data to effectively monitor and understand this biome. Within this context, and within the goals and framework of the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA), we evaluated the usefulness of spectral vegetation indices (VIs), to effectively monitor the Cerrado, detect land conversions, and discriminate and assess the conditions of the major structural types of Cerrado vegetation. Using a full hydrologic year (1995) of AVHRR, local-area-coverage (LAC), data over the Cerrado, converted to normalized difference vegetation index (NDVI) and soil adjusted vegetation index (SAVI), we were able to spatially discriminate three major communities based on their phenologic patterns. These included savanna formations and pasture sites, forested areas, and agricultural crops. We also analyzed wet and dry season, aircraft-based radiometric data and a ground-based set of biophysical measurements, collected over the Brasilia National Park (BNP), the largest LBA core site in the Cerrado biome. Overall, we found the MODIS vegetation indices, which include a continuity NDVI and the new enhanced vegetation index (EVI), to provide better performance capabilities with improved dynamic ranges and contrasts in seasonal dynamics. Land cover discrimination was favored by the NDVI, while the EVI more strongly responded to the seasonal contrast of the vegetative cover. Thus, the synergistic use of the MODIS VI products will very likely

  1. A long-life Na-air battery based on a soluble NaI catalyst.

    PubMed

    Yin, Wen-Wen; Shadike, Zulipiya; Yang, Yin; Ding, Fei; Sang, Lin; Li, Hong; Fu, Zheng-Wen

    2015-02-11

    A Na-air battery with NaI dissolved in a typical organic electrolyte could run up to 150 cycles with a capacity limit of 1000 mA h g(-1). The low charge voltage plateau of 3.2 V vs. Na(+)/Na in a Na-air battery should mainly be attributed to the oxidation reaction of active iodine anions.

  2. Silicene for Na-ion battery applications

    NASA Astrophysics Data System (ADS)

    Zhu, Jiajie; Schwingenschlögl, Udo

    2016-09-01

    Na-ion batteries are promising candidates to replace Li-ion batteries in large scale applications because of the advantages in natural abundance and cost of Na. Silicene has potential as the anode in Li-ion batteries but so far has not received attention with respect to Na-ion batteries. In this context, freestanding silicene, a graphene-silicene-graphene heterostructure, and a graphene-silicene superlattice are investigated for possible application in Na-ion batteries, using first-principles calculations. The calculated Na capacities of 954 mAh/g for freestanding silicene and 730 mAh/g for the graphene-silicene superlattice (10% biaxial tensile strain) are highly competitive and potentials of \\gt 0.3 {{V}} against the Na{}+/Na potential exceed the corresponding value of graphite. In addition, the diffusion barriers are predicted to be \\lt 0.3 {eV}.

  3. Revisiting the hydration structure of aqueous Na().

    PubMed

    Galib, M; Baer, M D; Skinner, L B; Mundy, C J; Huthwelker, T; Schenter, G K; Benmore, C J; Govind, N; Fulton, J L

    2017-02-28

    A combination of theory, X-ray diffraction (XRD) and extended x-ray absorption fine structure (EXAFS) are used to probe the hydration structure of aqueous Na(+). The high spatial resolution of the XRD measurements corresponds to Qmax = 24 Å(-1) while the first-reported Na K-edge EXAFS measurements have a spatial resolution corresponding to 2k = Qmax = 16 Å(-1). Both provide an accurate measure of the shape and position of the first peak in the Na-O pair distribution function, gNaO(r). The measured Na-O distances of 2.384 ± 0.003 Å (XRD) and 2.37 ± 0.024 Å (EXAFS) are in excellent agreement. These measurements show a much shorter Na-O distance than generally reported in the experimental literature (Na-Oavg ∼ 2.44 Å) although the current measurements are in agreement with recent neutron diffraction measurements. The measured Na-O coordination number from XRD is 5.5 ± 0.3. The measured structure is compared with both classical and first-principles density functional theory (DFT) simulations. Both of the DFT-based methods, revPBE and BLYP, predict a Na-O distance that is too long by about 0.05 Å with respect to the experimental data (EXAFS and XRD). The inclusion of dispersion interactions (-D3 and -D2) significantly worsens the agreement with experiment by further increasing the Na-O distance by 0.07 Å. In contrast, the use of a classical Na-O Lennard-Jones potential with SPC/E water accurately predicts the Na-O distance as 2.39 Å although the Na-O peak is over-structured with respect to experiment.

  4. The effect of Na vapor on the Na content of chondrules

    NASA Technical Reports Server (NTRS)

    Lewis, R. Dean; Lofgren, Gary E.; Franzen, Hugo F.; Windom, Kenneth E.

    1993-01-01

    Chondrules contain higher concentrations of volatiles (Na) than expected for melt droplets in the solar nebula. Recent studies have proposed that chondrules may have formed under non-canonical nebular conditions such as in particle/gas-rich clumps. Such chondrule formation areas may have contained significant Na vapor. To test the hypothesis of whether a Na-rich vapor would minimize Na volatilization reaction rates in a chondrule analog and maintain the Na value of the melt, experiments were designed where a Na-rich vapor could be maintained around the sample. A starting material with a melting point lower that typical chondrules was required to keep the logistics of working with Na volatilization from NaCl within the realm of feasibility. The Knippa basalt, a MgO-rich alkali olivine basalt with a melting temperature of 1325 +/- 5 C and a Na2O content of 3.05 wt%, was used as the chondrule analog. Experiments were conducted in a 1 atm, gas-mixing furnace with the fO2 controlled by a CO/CO2 gas mixture and fixed at the I-W buffer curve. To determine the extent of Na loss from the sample, initial experiments were conducted at high temperatures (1300 C - 1350 C) for duration of up to 72 h without a Na-rich vapor present. Almost all (up to 98%) Na was volatilized in runs of 72 h. Subsequent trials were conducted at 1330 C for 16 h in the presence of a Na-rich vapor, supplied by a NaCl-filled crucible placed in the bottom of the furnace. Succeeding Knudsen cell weight-loss mass-spectrometry analysis of NaCl determined the P(sub Na) for these experimental conditions to be in the 10(exp -6) atm range. This value is considered high for nebula conditions but is still plausible for non-canonical environments. In these trials the Na2O content of the glass was maintained or in some cases increased; Na2O values ranged from 2.62% wt to 4.37% wt. The Na content of chondrules may be controlled by the Na vapor pressure in the chondrule formation region. Most heating events capable

  5. Growth of binary organic NLO crystals: m.NA-p.NA and m.NA-CNA system

    NASA Technical Reports Server (NTRS)

    Singh, N. B.; Henningsen, T.; Hopkins, R. H.; Mazelsky, R.

    1993-01-01

    Experiments were carried out to grow 3.Nitroaniline (m.NA) crystals doped with 4.Nitroaniline (p.NA) and 2.chloro 4.Nitroaniline (CNA). The measured undercooling for m.NA, p.NA, and CNA were 0.21 tm K, 0.23 tm K, and 0.35 tm K respectively, where tm represents the melting temperature of the pure component. Because of the crystals' large heat of fusion and large undercooling, it was not possible to grow good quality crystals with low thermal gradients. In the conventional two-zone Bridgman furnace we had to raise the temperature of the hot zone above the decomposition temperature of CNA, p.NA, and m.NA to achieve the desired thermal gradient. To avoid decomposition, we used an unconventional Bridgman furnace. Two immiscible liquids, silicone oil and ethylene glycol, were used to build a special two-zone Bridgman furnace. A temperature gradient of 18 K/cm was achieved without exceeding the decomposition temperature of the crystal. The binary crystals, m.NA-p.NA and m.NA-CNA, were grown in centimeter size in this furnace. X-ray and optical characterization showed good optical quality.

  6. Modification of single Na+ channels by batrachotoxin.

    PubMed Central

    Quandt, F N; Narahashi, T

    1982-01-01

    The modifications in the properties of voltage-gated Na+ channels caused by batrachotoxin were studied by using the patch clamp method for measuring single channel currents from excised membranes of N1E-115 neuroblastoma cells. The toxin-modified open state of the Na+ channel has a decreased conductance in comparison to that of normal Na+ channels. The lifetime of the modified open state is drastically prolonged, and channels now continue to open during a maintained depolarization so that the probability of a channel being open becomes constant. Modified and normal open states of Na+ channels coexist in batrachotoxin-exposed membrane patches. Unlike the normal condition, Na+ channels exposed to batrachotoxin open spontaneously at large negative potentials. These spontaneous openings apparently cause the toxin-induced increase in Na+ permeability which, in turn, causes membrane depolarization. PMID:6292915

  7. Maintaining the NA atmosphere of Mercury

    NASA Astrophysics Data System (ADS)

    Killen, R. M.; Morgan, T. H.

    1993-02-01

    The possible sources of the Na atmosphere of Mercury are calculatively studied. The likely structure, composition, and temperature of the planet's upper crust is examined along with the probable flux of Na from depth by grain boundary diffusion and by Knudsen flow. The creation of fresh regolith is considered along with mechanisms for supplying Na from the surface to the exosphere. The implications of the calculations for the probable abundances in the regolith are discussed.

  8. Maintaining the Na atmosphere of Mercury

    NASA Technical Reports Server (NTRS)

    Killen, Rosemary M.; Morgan, Thomas H.

    1993-01-01

    The possible sources of the Na atmosphere of Mercury are calculatively studied. The likely structure, composition, and temperature of the planet's upper crust is examined along with the probable flux of Na from depth by grain boundary diffusion and by Knudsen flow. The creation of fresh regolith is considered along with mechanisms for supplying Na from the surface to the exosphere. The implications of the calculations for the probable abundances in the regolith are discussed.

  9. NA-NET numerical analysis net

    SciTech Connect

    Dongarra, J. . Dept. of Computer Science Oak Ridge National Lab., TN ); Rosener, B. . Dept. of Computer Science)

    1991-12-01

    This report describes a facility called NA-NET created to allow numerical analysts (na) an easy method of communicating with one another. The main advantage of the NA-NET is uniformity of addressing. All mail is addressed to the Internet host na-net.ornl.gov'' at Oak Ridge National Laboratory. Hence, members of the NA-NET do not need to remember complicated addresses or even where a member is currently located. As long as moving members change their e-mail address in the NA-NET everything works smoothly. The NA-NET system is currently located at Oak Ridge National Laboratory. It is running on the same machine that serves netlib. Netlib is a separate facility that distributes mathematical software via electronic mail. For more information on netlib consult, or send the one-line message send index'' to netlib{at}ornl.gov. The following report describes the current NA-NET system from both a user's perspective and from an implementation perspective. Currently, there are over 2100 members in the NA-NET. An average of 110 mail messages pass through this facility daily.

  10. NA-NET numerical analysis net

    SciTech Connect

    Dongarra, J. |; Rosener, B.

    1991-12-01

    This report describes a facility called NA-NET created to allow numerical analysts (na) an easy method of communicating with one another. The main advantage of the NA-NET is uniformity of addressing. All mail is addressed to the Internet host ``na-net.ornl.gov`` at Oak Ridge National Laboratory. Hence, members of the NA-NET do not need to remember complicated addresses or even where a member is currently located. As long as moving members change their e-mail address in the NA-NET everything works smoothly. The NA-NET system is currently located at Oak Ridge National Laboratory. It is running on the same machine that serves netlib. Netlib is a separate facility that distributes mathematical software via electronic mail. For more information on netlib consult, or send the one-line message ``send index`` to netlib{at}ornl.gov. The following report describes the current NA-NET system from both a user`s perspective and from an implementation perspective. Currently, there are over 2100 members in the NA-NET. An average of 110 mail messages pass through this facility daily.

  11. Simulation study of Na-majorite

    NASA Astrophysics Data System (ADS)

    Dymshits, A.; Vinograd, V.; Paulsen, N.; Winkler, B.; Perchuk, L.; Bobrov, A.

    2009-04-01

    Garnets, which are found as inclusions in diamonds, often have the excess of Na2O and SiO2 [Stachel, 2001]. Experimental studies suggest that Na is incorporated in pyrope-rich garnet via the coupled substitution Mg+Al=Na+Si [Bobrov et al., 2008]. This study is concerned with the determination of the structure and the thermodynamic properties of NaGrt (Na2MgSi5O12), which is assumed to be the end-member of pyrope-rich garnets with the excess of Na2O and SiO2. Static lattice energy calculations were performed with the program GULP [Gale & Rohl, 2003] using the force-field model [Vinograd et al., 2007] for 200 structures of Na2MgSi5O12 composition. These structures were prepared from Ia3-d pyrope Mg3Al2Si3O12 by replacing all octahedral Al atoms with Si and 2/3 of Mg atoms with Na. The distribution of Mg and Na was varied randomly. The static energies of these structures were cluster expanded using 8 pairwise effective cluster interactions (ECI). The ECIs were used to constrain Monte Carlo simulations within a 4×4×4 supercell (NNN exchangeable sites). The annealing experiments have shown that the lowest energy structure has the space group I4

  12. Painful Na-channelopathies: an expanding universe.

    PubMed

    Waxman, Stephen G

    2013-07-01

    The universe of painful Na-channelopathies--human disorders caused by mutations in voltage-gated sodium channels--has recently expanded in three dimensions. We now know that mutations of sodium channels cause not only rare genetic 'model disorders' such as inherited erythromelalgia and channelopathy-associated insensitivity to pain but also common painful neuropathies. We have learned that mutations of NaV1.8, as well as mutations of NaV1.7, can cause painful Na-channelopathies. Moreover, recent studies combining atomic level structural models and pharmacogenomics suggest that the goal of genomically guided pain therapy may not be unrealistic.

  13. Na+/Ca2+ exchange and Na+/K+-ATPase in the heart

    PubMed Central

    Shattock, Michael J; Ottolia, Michela; Bers, Donald M; Blaustein, Mordecai P; Boguslavskyi, Andrii; Bossuyt, Julie; Bridge, John H B; Chen-Izu, Ye; Clancy, Colleen E; Edwards, Andrew; Goldhaber, Joshua; Kaplan, Jack; Lingrel, Jerry B; Pavlovic, Davor; Philipson, Kenneth; Sipido, Karin R; Xie, Zi-Jian

    2015-01-01

    This paper is the third in a series of reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation–contraction coupling and arrhythmias: Na+ channel and Na+ transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on cardiac Na+/Ca2+ exchange (NCX) and Na+/K+-ATPase (NKA). While the relevance of Ca2+ homeostasis in cardiac function has been extensively investigated, the role of Na+ regulation in shaping heart function is often overlooked. Small changes in the cytoplasmic Na+ content have multiple effects on the heart by influencing intracellular Ca2+ and pH levels thereby modulating heart contractility. Therefore it is essential for heart cells to maintain Na+ homeostasis. Among the proteins that accomplish this task are the Na+/Ca2+ exchanger (NCX) and the Na+/K+ pump (NKA). By transporting three Na+ ions into the cytoplasm in exchange for one Ca2+ moved out, NCX is one of the main Na+ influx mechanisms in cardiomyocytes. Acting in the opposite direction, NKA moves Na+ ions from the cytoplasm to the extracellular space against their gradient by utilizing the energy released from ATP hydrolysis. A fine balance between these two processes controls the net amount of intracellular Na+ and aberrations in either of these two systems can have a large impact on cardiac contractility. Due to the relevant role of these two proteins in Na+ homeostasis, the emphasis of this review is on recent developments regarding the cardiac Na+/Ca2+ exchanger (NCX1) and Na+/K+ pump and the controversies that still persist in the field. PMID:25772291

  14. Exploration of NaVOPO4 as a cathode for a Na-ion battery.

    PubMed

    Song, Jie; Xu, Maowen; Wang, Long; Goodenough, John B

    2013-06-11

    Monoclinic NaVOPO4 is explored as a cathode material for a sodium ion battery. It exhibits electrochemical activity operating at an average potential of 3.6 V (vs. Na(+)/Na) and delivers a reversible capacity of 90 mA h g(-1) at 1/15 C.

  15. Negative electrodes for Na-ion batteries.

    PubMed

    Dahbi, Mouad; Yabuuchi, Naoaki; Kubota, Kei; Tokiwa, Kazuyasu; Komaba, Shinichi

    2014-08-07

    Research interest in Na-ion batteries has increased rapidly because of the environmental friendliness of sodium compared to lithium. Throughout this Perspective paper, we report and review recent scientific advances in the field of negative electrode materials used for Na-ion batteries. This paper sheds light on negative electrode materials for Na-ion batteries: carbonaceous materials, oxides/phosphates (as sodium insertion materials), sodium alloy/compounds and so on. These electrode materials have different reaction mechanisms for electrochemical sodiation/desodiation processes. Moreover, not only sodiation-active materials but also binders, current collectors, electrolytes and electrode/electrolyte interphase and its stabilization are essential for long cycle life Na-ion batteries. This paper also addresses the prospect of Na-ion batteries as low-cost and long-life batteries with relatively high-energy density as their potential competitive edge over the commercialized Li-ion batteries.

  16. High NA Nicrostepper Final Optical Design Report

    SciTech Connect

    Hudyma, R

    1999-09-24

    The development of a new EUV high NA small-field exposure tool has been proposed for obtaining mask defect printability data in a timeframe several years before beta-tools are available. The imaging system for this new Micro-Exposure Tool (MET), would have a numerical aperture (NA) of about 0.3, similar to the NA for a beta-tool, but substantially larger than the 0.10 NA for the Engineering Test Stand (ETS) and 0.088 NA for the existing 10x Microstepper. This memorandum discusses the development and summarizes the performance of the camera for the MET and includes a listing of the design prescription, detailed analysis of the distortion, and analysis demonstrating the capability to resolution 30 nm features under the conditions of partially coherent illumination.

  17. Na+ binding to the Na(+)-glucose cotransporter is potential dependent.

    PubMed

    Bennett, E; Kimmich, G A

    1992-02-01

    Activity of the Na(+)-glucose cotransporter in LLC-PK1 epithelial cells was assayed by measuring sugar-induced currents (IAMG) using whole cell recording techniques. IAMG was compared among cells by standardizing the measured currents to cell size using cell capacitance measurements. IAMG at a given membrane potential was measured as a function of alpha-methylglucoside (AMG) concentration and can be fit to Michaelis-Menten kinetics. IAMG at varying Na+ concentrations can be described by the Hill equation with a Hill coefficient of 1.6 at all tested potentials. At high external Na+ levels (155 mM), Na+ is at least 90% saturating at all tested potentials. Maximal currents at a given membrane potential (Im) are calculated from the Michaelis-Menten equation fit to data measuring IAMG vs. AMG concentration at a constant Na+ concentration. Im showed potential dependence under all conditions. Potential-dependent Na+ binding rate(s) cannot alone explain the observed potential dependence of Im under saturating Na+ conditions. Therefore, because Im is potential dependent, at least one step of the transport cycle other than external Na+ binding must be potential dependent. Im was also calculated from data taken at 40 mM external Na+. At all potentials studied, Im at 155 mM Na+ is greater than Im calculated at 40 mM Na+. This implies that the rate of external Na+ binding to the transporter at 40 mM also affects the maximal transport rate. Furthermore, Im at 40 mM external Na+ increases with hyperpolarization faster than Im at 155 mM Na+. Together, these facts indicate that the rate at which Na+ binds to the transporter is also potential dependent.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Effects of the Omnibus Budget Reconciliation Act of 1981 (OBRA) Welfare Changes and the Recession on Poverty. Subcommittee on Oversight and Subcommittee on Public Assistance and Unemployment Compensation of the Committee on Ways and Means. U.S. House of Representatives, 98th Congress, 2nd Session.

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. House Committee on Ways and Means.

    Possible causes for the rapid increase in the poverty rate from 1980 to 1982 were investigated, with two factors in particular being considered: the impact of the welfare program provisions of the Omnibus Budget Reconciliation Act of 1981 (OBRA), and the recessionary economy experienced during that year. The basic study design used a computer…

  19. Pharmacological modulation of human cardiac Na+ channels.

    PubMed

    Krafte, D S; Davison, K; Dugrenier, N; Estep, K; Josef, K; Barchi, R L; Kallen, R G; Silver, P J; Ezrin, A M

    1994-02-15

    Pharmacological modulation of human sodium current was examined in Xenopus oocytes expressing human heart Na+ channels. Na+ currents activated near -50 mV with maximum current amplitudes observed at -20 mV. Steady-state inactivation was characterized by a V1/2 value of -57 +/- 0.5 mV and a slope factor (k) of 7.3 +/- 0.3 mV. Sodium currents were blocked by tetrodotoxin with an IC50 value of 1.8 microM. These properties are consistent with those of Na+ channels expressed in mammalian myocardial cells. We have investigated the effects of several pharmacological agents which, with the exception of lidocaine, have not been characterized against cRNA-derived Na+ channels expressed in Xenopus oocytes. Lidocaine, quinidine and flecainide blocked resting Na+ channels with IC50 values of 521 microM, 198 microM, and 41 microM, respectively. Use-dependent block was also observed for all three agents, but concentrations necessary to induce block were higher than expected for quinidine and flecainide. This may reflect differences arising due to expression in the Xenopus oocyte system or could be a true difference in the interaction between human cardiac Na+ channels and these drugs compared to other mammalian Na+ channels. Importantly, however, this result would not have been predicted based upon previous studies of mammalian cardiac Na+ channels. The effects of DPI 201-106, RWJ 24517, and BDF 9148 were also tested and all three agents slowed and/or removed Na+ current inactivation, reduced peak current amplitudes, and induced use-dependent block. These data suggest that the alpha-subunit is the site of interaction between cardiac Na+ channels and Class I antiarrhythmic drugs as well as inactivation modifiers such as DPI 201-106.

  20. Na-doped optical Germanium bulk crystals

    NASA Astrophysics Data System (ADS)

    Pekar, G. S.; Singaevsky, A. F.

    2012-09-01

    In an effort to develop a material for infrared (IR) optics with improved parameters, bulk crystals of optical germanium doped with Na have been first grown and studied. Single-crystalline and coarse-crystalline Ge:Na boules of different shapes and dimensions, up to 10 kg by weight, have been grown. Sodium was incorporated into the Ge crystal during the crystal growing from the melt. Despite the fact that Na contamination in the source material was not strictly controlled, the density of Na in the grown crystals determined by the neutron activation analysis as well as by the glow discharge mass spectrometry did not exceed 1015 cm-3. Just this value may be supposed to be close to the solubility limit of Na incorporated in Ge in the course of bulk crystal growth. A first demonstration of donor behavior of Na in bulk Ge crystals is made by means of a thermoelectric type of testing. An interstitial location of Na impurity has been verified by experiments on donor drift in the dc electric field. The crystals are grown with free electron density in the range from 5ṡ1013 to 4ṡ1014 cm-3 which is optimal for using Ge crystals as an optical material for fabricating passive elements of the IR technique. A comparison between the properties of Ge:Na crystals and Ge crystals doped with Sb, a conventional impurity in optical germanium, grown under the same technological conditions and from the same intrinsic Ge as a source material, revealed a number of advantages of Ge:Na crystals; among them, the higher transparency in the IR region, smaller radiation scattering and higher regular optical transmission, lower dislocation density, more uniform distribution of electrical and optical characteristics over the crystal volume, the identity of optical parameters in the single-crystalline, and coarse-crystalline boules. No degradation of optical elements fabricated from Ge:Na crystals was detected in the course of their commercial application, starting from 1998.

  1. Anomalously high Na(+) and low Li(+) mobility in intercalated Na2Ti6O13.

    PubMed

    Ling, Chen; Zhang, Ruigang

    2017-04-12

    We report an anomalous diffusion behavior in intercalated Na2Ti6O13. Using first-principles calculations, the direct migration of inserted Na(+) along the tunnel direction is predicted to have a barrier of 0.24-0.44 eV, while the migration of inserted Li(+) along the tunnel direction has a barrier of 0.86-1.15 eV. Although Li(+) can also diffuse along a zig-zag path in the tunnel, the barrier of 0.86-0.99 eV is still much higher than that for Na(+). Our results surprisingly lead to the conclusion that the diffusion of larger Na(+) is 4-8 orders of magnitude faster than Li(+) in the same host lattice, and explain the experimentally observed exceptional rate capability of Na2Ti6O13 as the Na-ion battery anode. The anomalous diffusion behavior is attributed to the geometric features of Na2Ti6O13. For migration of Li(+) it is necessary to weaken Li-O bonds and to overcome the repulsion between Li and host Na ions simultaneously, while for Na(+) diffusion the improved Na-O bonding at the transition state partially compensates for the energy penalty from the repulsion of host Na ions.

  2. Cytosolic Na+ Controls an Epithelial Na+ Channel Via the Go Guanine Nucleotide-Binding Regulatory Protein

    NASA Astrophysics Data System (ADS)

    Komwatana, P.; Dinudom, A.; Young, J. A.; Cook, D. I.

    1996-07-01

    In tight Na+-absorbing epithelial cells, the rate of Na+ entry through amiloride-sensitive apical membrane Na+ channels is matched to basolateral Na+ extrusion so that cell Na+ concentration and volume remain steady. Control of this process by regulation of apical Na+ channels has been attributed to changes in cytosolic Ca2+ concentration or pH, secondary to changes in cytosolic Na+ concentration, although cytosolic Cl- seems also to be involved. Using mouse mandibular gland duct cells, we now demonstrate that increasing cytosolic Na+ concentration inhibits apical Na+ channels independent of changes in cytosolic Ca2+, pH, or Cl-, and the effect is blocked by GDP-β -S, pertussis toxin, and antibodies against the α -subunits of guanine nucleotide-binding regulatory proteins (Go). In contrast, the inhibitory effect of cytosolic anions is blocked by antibodies to inhibitory guanine nucleotide-binding regulatory proteins (Gi1/Gi2. It thus appears that apical Na+ channels are regulated by Go and Gi proteins, the activities of which are controlled, respectively, by cytosolic Na+ and Cl-.

  3. Cytosolic Na+ controls and epithelial Na+ channel via the Go guanine nucleotide-binding regulatory protein.

    PubMed Central

    Komwatana, P; Dinudom, A; Young, J A; Cook, D I

    1996-01-01

    In tight Na+-absorbing epithelial cells, the fate of Na+ entry through amiloride-sensitive apical membrane Na+ channels is matched to basolateral Na+ extrusion so that cell Na+ concentration and volume remain steady. Control of this process by regulation of apical Na+ channels has been attributed to changes in cytosolic Ca2+ concentration or pH, secondary to changes in cytosolic Na+ concentration, although cytosolic Cl- seems also to be involved. Using mouse mandibular gland duct cells, we now demonstrate that increasing cytosolic Na+ concentration inhibits apical Na+ channels independent of changes in cytosolic Ca2+, pH, or Cl-, and the effect is blocked by GDP-beta-S, pertussis toxin, and antibodies against the alpha-subunits of guanine nucleotide-binding regulatory proteins (Go). In contrast, the inhibitory effect of cytosolic anions is blocked by antibodies to inhibitory guanine nucleotide-binding regulatory proteins (Gi1/Gi2. It thus appears that apical Na+ channels are regulated by Go and Gi proteins, the activities of which are controlled, respectively, by cytosolic Na+ and Cl-. Images Fig. 4 PMID:8755611

  4. Laser-induced ionization of Na vapor

    SciTech Connect

    Wu, R.C.Y.; Judge, D.L.; Roussel, F.; Carre, B.; Breger, P.; Spiess, G.

    1982-01-01

    The production of Na/sub 2//sup +/ ions by off-resonant laser excitation in the 5800-6200A region mainly results from two-photon absorption by the Na/sub 2/ molecule to highly excited gerade states followed by (a) direct ionization by absorbing a third photon or (b) coupling to the molecular Na/sub 2/ D/sup 1/PI..mu.. Rydberg state which is subsequently ionized by absorbing a third photon. This mechanism, i.e., a two-photon resonance three photon ionization process, explains a recent experimental observation of Roussel et al. It is suggested that the very same mechanism is also responsible for a similar observation reported by Polak-Dingels et al in their work using two crossed Na beams. In the latter two studies the laser-induced associative ionization processes were reported to be responsible for producing the Na/sub 2//sup +/ ion. From the ratio of molecular to atomic concentration in the crossed beam experiment of Polak-Dingels et al we estimate that the cross section for producing Na/sub 2//sup +/ through laser-induced associative ionization is at least four orders of magnitude smaller than ionization through the two-photon resonance three photon ionization process in Na/sub 2/ molecules.

  5. Laser-induced ionization of Na vapor

    NASA Astrophysics Data System (ADS)

    Wu, C. Y. Robert; Judge, D. L.; Roussel, F.; Carré, B.; Breger, P.; Spiess, G.

    1982-09-01

    The production of Na2+ ions by off-resonant laser excitation in the 5800-6200Å region mainly results from two-photon absorption by the Na2 molecule to highly excited gerade states followed by (a) direct ionization by absorbing a third photon or (b) coupling to the molecular Na2 D1Πu Rydberg state which is subsequently ionized by absorbing a third photon. This mechanism, i.e., a two-photon resonance three photon ionization process, explains a recent experimental observation of Roussel et al. It is suggested that the very same mechanism is also responsible for a similar observation reported by Polak-Dingels et al in their work using two crossed Na beams. In the latter two studies the laser-induced associative ionization processes were reported to be responsible for producing the Na2+ ion. From the ratio of molecular to atomic concentration in the crossed beam experiment of Polak-Dingels et al. we estimate that the cross section for producing Na2+ through laser-induced associative ionization is at least four orders of magnitude smaller than ionization through the two-photon resonance three photon ionization process in Na2 molecules.

  6. NMR studies on Na+ transport in Synechococcus PCC 6311

    NASA Technical Reports Server (NTRS)

    Nitschmann, W. H.; Packer, L.

    1992-01-01

    The freshwater cyanobacterium Synechococcus PCC 6311 is able to adapt to grow after sudden exposure to salt (NaCl) stress. We have investigated the mechanism of Na+ transport in these cells during adaptation to high salinity. Na+ influx under dark aerobic conditions occurred independently of delta pH or delta psi across the cytoplasmic membrane, ATPase activity, and respiratory electron transport. These findings are consistent with the existence of Na+/monovalent anion cotransport or simultaneous Na+/H+ +anion/OH- exchange. Na+ influx was dependent on Cl-, Br-, NO3-, or NO2-. No Na+ uptake occurred after addition of NaI, NaHCO3, or Na2SO4. Na+ extrusion was absolutely dependent on delta pH and on an ATPase activity and/or on respiratory electron transport. This indicates that Na+ extrusion via Na+/H+ exchange is driven by primary H+ pumps in the cytoplasmic membrane. Cells grown for 4 days in 0.5 m NaCl medium, "salt-grown cells," differ from control cells by a lower maximum velocity of Na+ influx and by lower steady-state ratios of [Na+]in/[Na+]out. These results indicate that cells grown in high-salt medium increase their capacity to extrude Na+. During salt adaptation Na+ extrusion driven by respiratory electron transport increased from about 15 to 50%.

  7. Characteristics and pharmacological regulation of epithelial Na+ channel (ENaC) and epithelial Na+ transport.

    PubMed

    Marunaka, Yoshinori

    2014-01-01

    Epithelial Na(+) transport participates in control of various body functions and conditions: e.g., homeostasis of body fluid content influencing blood pressure, control of amounts of fluids covering the apical surface of alveolar epithelial cells at appropriate levels for normal gas exchange, and prevention of bacterial/viral infection. Epithelial Na(+) transport via the transcellular pathway is mediated by the entry step of Na(+) across the apical membrane via Epithelial Na(+) Channel (ENaC) located at the apical membrane, and the extrusion step of Na(+) across the basolateral membrane via the Na(+),K(+)-ATPase located at the basolateral membrane. The rate-limiting step of the epithelial Na(+) transport via the transcellular pathway is generally recognized to be the entry step of Na(+) across the apical membrane via ENaC. Thus, up-/down-regulation of ENaC essentially participates in regulatory systems of blood pressure and normal gas exchange. Amount of ENaC-mediated Na(+) transport is determined by the number of ENaCs located at the apical membrane, activity (open probability) of individual ENaC located at the apical membrane, single channel conductance of ENaC located at the apical membrane, and driving force for the Na(+) entry via ENaCs across the apical membrane. In the present review article, I discuss the characteristics of ENaC and how these factors are regulated.

  8. Glutathionylation-Dependence of Na(+)-K(+)-Pump Currents Can Mimic Reduced Subsarcolemmal Na(+) Diffusion.

    PubMed

    Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald J; Rasmussen, Helge H

    2016-03-08

    The existence of a subsarcolemmal space with restricted diffusion for Na(+) in cardiac myocytes has been inferred from a transient peak electrogenic Na(+)-K(+) pump current beyond steady state on reexposure of myocytes to K(+) after a period of exposure to K(+)-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na(+) that accumulated in the diffusion-restricted space during pump inhibition in K(+)-free extracellular solution. However, there are no known physical barriers that account for such restricted Na(+) diffusion, and we examined if changes of activity of the Na(+)-K(+) pump itself cause the transient peak current. Reexposure to K(+) reproduced a transient current beyond steady state in voltage-clamped ventricular myocytes as reported by others. Persistence of it when the Na(+) concentration in patch pipette solutions perfusing the intracellular compartment was high and elimination of it with K(+)-free pipette solution could not be reconciled with restricted subsarcolemmal Na(+) diffusion. The pattern of the transient current early after pump activation was dependent on transmembrane Na(+)- and K(+) concentration gradients suggesting the currents were related to the conformational poise imposed on the pump. We examined if the currents might be accounted for by changes in glutathionylation of the β1 Na(+)-K(+) pump subunit, a reversible oxidative modification that inhibits the pump. Susceptibility of the β1 subunit to glutathionylation depends on the conformational poise of the Na(+)-K(+) pump, and glutathionylation with the pump stabilized in conformations equivalent to those expected to be imposed on voltage-clamped myocytes supported this hypothesis. So did elimination of the transient K(+)-induced peak Na(+)-K(+) pump current when we included glutaredoxin 1 in patch pipette solutions to reverse glutathionylation. We conclude that transient K(+)-induced peak Na(+)-K(+) pump current reflects the effect

  9. Interaction between Na+ and H+ ions on Na-H exchange in sheep cardiac Purkinje fibers.

    PubMed

    Wu, M L; Vaughan-Jones, R D

    1997-04-01

    The interaction between Na+ and H+ ions upon Na-H exchange (NHE) was examined in sheep cardiac Purkinje fibers. Acid equivalent fluxes through NHE were examined using recordings of intracellular pH and Na+ in isolated preparations measured with ion selective microelectrodes. The extent of acid-extrusion by NHE was estimated from pH(i) recovery-rate, multiplied by beta(i) (intracellular buffering power) in response to an internal acid load induced by 20 mm NH4Cl removal (nominally HCO3- free media). A mixed inhibitory effect was found of extracellular H+ on external Na+-activation of NHE (i.e. an increase, at low pH(o), in the apparent Michaelis constant for external Na+ ions [K(Nao)(0.5)] and a decrease in the maximum transport rate [V(Nao)(max)]). In addition, we confirmed that the stoichiometry of Na(o) binding is unaffected by the pH(o) (between 7.5 and 6.5), showing a Hill coefficient close to one. The interaction between Na+ and H+ ions at the internal face of the cardiac NHE was also studied. Our evidence suggests that an increase in the intracellular Na+ ion concentration ([Na+]i) inhibits acid efflux and that this inhibition can be approximated by the decrease in thermodynamic driving force caused by reducing the transmembrane Na+ gradient. It appears, however, that small variations in [Na+]i from the normal resting level (intracellular sodium activity, a(i)Na = 7 to 13 mm) have little or no effect on acid efflux, suggesting that variation of a(i)Na is not a physiologically important controller of NHE activity in heart.

  10. Thermodynamic Model for the Solubility of Cr(OH)(3)(am) in Concentrated NaOH and NaOH-NaNO3 Solutions

    SciTech Connect

    Rai, Dhanpat ); Hess, Nancy J. ); Rao, Linfeng; Zhang, Zhicheng; Felmy, Andrew R. ); Moore, Dean A. ); Clark, Sue B.; Lumetta, Gregg J. )

    2001-12-01

    The objectives of this study were to develop a reliable thermodynamic model for predicting Cr(III) behavior in concentrated NaOH and in mixed NaOH-NaNO3 solutions for application to effective caustic leaching strategies for high-level tank sludges. To meet these objectives, the solubility of Cr(OH)3(am) was measured in 0.003 to 10.5 m NaOH, 3.0 m es in NaOH concentration...

  11. Hydrogen-fluorine exchange in NaBH4-NaBF4.

    PubMed

    Rude, L H; Filsø, U; D'Anna, V; Spyratou, A; Richter, B; Hino, S; Zavorotynska, O; Baricco, M; Sørby, M H; Hauback, B C; Hagemann, H; Besenbacher, F; Skibsted, J; Jensen, T R

    2013-11-07

    Hydrogen-fluorine exchange in the NaBH4-NaBF4 system is investigated using a range of experimental methods combined with DFT calculations and a possible mechanism for the reactions is proposed. Fluorine substitution is observed using in situ synchrotron radiation powder X-ray diffraction (SR-PXD) as a new Rock salt type compound with idealized composition NaBF2H2 in the temperature range T = 200 to 215 °C. Combined use of solid-state (19)F MAS NMR, FT-IR and DFT calculations supports the formation of a BF2H2(-) complex ion, reproducing the observation of a (19)F chemical shift at -144.2 ppm, which is different from that of NaBF4 at -159.2 ppm, along with the new absorption bands observed in the IR spectra. After further heating, the fluorine substituted compound becomes X-ray amorphous and decomposes to NaF at ~310 °C. This work shows that fluorine-substituted borohydrides tend to decompose to more stable compounds, e.g. NaF and BF3 or amorphous products such as closo-boranes, e.g. Na2B12H12. The NaBH4-NaBF4 composite decomposes at lower temperatures (300 °C) compared to NaBH4 (476 °C), as observed by thermogravimetric analysis. NaBH4-NaBF4 (1:0.5) preserves 30% of the hydrogen storage capacity after three hydrogen release and uptake cycles compared to 8% for NaBH4 as measured using Sievert's method under identical conditions, but more than 50% using prolonged hydrogen absorption time. The reversible hydrogen storage capacity tends to decrease possibly due to the formation of NaF and Na2B12H12. On the other hand, the additive sodium fluoride appears to facilitate hydrogen uptake, prevent foaming, phase segregation and loss of material from the sample container for samples of NaBH4-NaF.

  12. Deliquescence of NaCl-NaNO3, KNO3-NaNO3, and NaCl-KNO3 Salt Mixtures From 90 to 120?C

    SciTech Connect

    Carroll, S A; Craig, L; Wolery, T J

    2004-10-20

    We conducted reversed deliquescence experiments in saturated NaCl-NaNO{sub 3}-H{sub 2}O, KNO{sub 3}-NaNO{sub 3}-H{sub 2}O, and NaCl-KNO{sub 3}-H{sub 2}O systems from 90 to 120 C as a function of relative humidity and solution composition. NaCl, NaNO{sub 3}, and KNO{sub 3} represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV, USA. Discrepancy between model prediction and experimental code can be as high as 8% for relative humidity and 50% for dissolved ion concentration. The discrepancy is attributed primarily to the use of 25 C models for Cl-NO{sub 3} and K-NO{sub 3} ion interactions in the current Yucca Mountain Project high-temperature Pitzer model to describe the non-ideal behavior of these highly concentrated solutions.

  13. Vascular contractile reactivity in hypotension due to reduced renal reabsorption of Na(+) and restricted dietary Na().

    PubMed

    Alshahrani, Saeed; Rapoport, Robert M; Soleimani, Manoocher

    2017-03-01

    Reduced renal Na(+) reabsorption along with restricted dietary Na(+) depletes intravascular plasma volume which can then result in hypotension. Whether hypotension occurs and the magnitude of hypotension depends in part on compensatory angiotensin II-mediated increased vascular resistance. We investigated whether the ability of vascular resistance to mitigate the hypotension was compromised by decreased contractile reactivity. In vitro reactivity was investigated in aorta from mouse models of reduced renal Na(+) reabsorption and restricted dietary Na(+) associated with considerable hypotension and renin-angiotensin system activation: (1) the Na(+)-Cl(-)-Co-transporter (NCC) knockout (KO) with Na(+) restricted diet (0.1%, 2 weeks) and (2) the relatively more severe pendrin (apical chloride/bicarbonate exchanger) and NCC double KO. Contractile sensitivity to KCl, phenylephrine, and/or U46619 remained unaltered in aorta from both models. Maximal KCl and phenylephrine contraction expressed as force/aorta length from NCC KO with Na(+)-restricted diet remained unaltered, while in pendrin/NCC double KO were reduced to 49 and 64%, respectively. Wet weight of aorta from NCC KO with Na(+)-restricted diet remained unaltered, while pendrin/NCC double KO was reduced to 67%, consistent with decreased medial width determined with Verhoeff-Van Gieson stain. These findings suggest that hypotension associated with severe intravascular volume depletion, as the result of decreased renal Na(+) reabsorption, may in part be due to decreased contractile reactivity as a consequence of reduced vascular hypertrophy.

  14. Glutamate Water Gates in the Ion Binding Pocket of Na(+) Bound Na(+), K(+)-ATPase.

    PubMed

    Han, Minwoo; Kopec, Wojciech; Solov'yov, Ilia A; Khandelia, Himanshu

    2017-01-13

    The dynamically changing protonation states of the six acidic amino acid residues in the ion binding pocket of the Na(+), K(+) -ATPase (NKA) during the ion transport cycle are proposed to drive ion binding, release and possibly determine Na(+) or K(+) selectivity. We use molecular dynamics (MD) and density functional theory (DFT) simulations to determine the protonation scheme of the Na(+) bound conformation of NKA. MD simulations of all possible protonation schemes show that the bound Na(+) ions are most stably bound when three or four protons reside in the binding sites, and that Glu954 in site III is always protonated. Glutamic acid residues in the three binding sites act as water gates, and their deprotonation triggers water entry to the binding sites. From DFT calculations of Na(+) binding energies, we conclude that three protons in the binding site are needed to effectively bind Na(+) from water and four are needed to release them in the next step. Protonation of Asp926 in site III will induce Na(+) release, and Glu327, Glu954 and Glu779 are all likely to be protonated in the Na(+) bound occluded conformation. Our data provides key insights into the role of protons in the Na(+) binding and release mechanism of NKA.

  15. Anion-coupled Na efflux mediated by the human red blood cell Na/K pump

    PubMed Central

    1990-01-01

    The red cell Na/K pump is known to continue to extrude Na when both Na and K are removed from the external medium. Because this ouabain- sensitive flux occurs in the absence of an exchangeable cation, it is referred to as uncoupled Na efflux. This flux is also known to be inhibited by 5 mM Nao but to a lesser extent than that inhibitable by ouabain. Uncoupled Na efflux via the Na/K pump therefore can be divided into a Nao-sensitive and Nao-insensitive component. We used DIDS- treated, SO4-equilibrated human red blood cells suspended in HEPES- buffered (pHo 7.4) MgSO4 or (Tris)2SO4, in which we measured 22Na efflux, 35SO4 efflux, and changes in the membrane potential with the fluorescent dye, diS-C3 (5). A principal finding is that uncoupled Na efflux occurs electroneurally, in contrast to the pump's normal electrogenic operation when exchanging Nai for Ko. This electroneutral uncoupled efflux of Na was found to be balanced by an efflux of cellular anions. (We were unable to detect any ouabain-sensitive uptake of protons, measured in an unbuffered medium at pH 7.4 with a Radiometer pH-STAT.) The Nao-sensitive efflux of Nai was found to be 1.95 +/- 0.10 times the Nao-sensitive efflux of (SO4)i, indicating that the stoichiometry of this cotransport is two Na+ per SO4=, accounting for 60-80% of the electroneutral Na efflux. The remainder portion, that is, the ouabain-sensitive Nao-insensitive component, has been identified as PO4-coupled Na transport and is the subject of a separate paper. That uncoupled Na efflux occurs as a cotransport with anions is supported by the result, obtained with resealed ghosts, that when internal and external SO4 was substituted by the impermeant anion, tartrate i,o, the efflux of Na was inhibited 60-80%. This inhibition could be relieved by the inclusion, before DIDS treatment, of 5 mM Cli,o. Addition of 10 mM Ko to tartrate i,o ghosts, with or without Cli,o, resulted in full activation of Na/K exchange and the pump's electrogenicity

  16. Glutamate Water Gates in the Ion Binding Pocket of Na+ Bound Na+, K+-ATPase

    PubMed Central

    Han, Minwoo; Kopec, Wojciech; Solov’yov, Ilia A.; Khandelia, Himanshu

    2017-01-01

    The dynamically changing protonation states of the six acidic amino acid residues in the ion binding pocket of the Na+, K+ -ATPase (NKA) during the ion transport cycle are proposed to drive ion binding, release and possibly determine Na+ or K+ selectivity. We use molecular dynamics (MD) and density functional theory (DFT) simulations to determine the protonation scheme of the Na+ bound conformation of NKA. MD simulations of all possible protonation schemes show that the bound Na+ ions are most stably bound when three or four protons reside in the binding sites, and that Glu954 in site III is always protonated. Glutamic acid residues in the three binding sites act as water gates, and their deprotonation triggers water entry to the binding sites. From DFT calculations of Na+ binding energies, we conclude that three protons in the binding site are needed to effectively bind Na+ from water and four are needed to release them in the next step. Protonation of Asp926 in site III will induce Na+ release, and Glu327, Glu954 and Glu779 are all likely to be protonated in the Na+ bound occluded conformation. Our data provides key insights into the role of protons in the Na+ binding and release mechanism of NKA. PMID:28084301

  17. Stoichiometry and Na+ binding cooperativity of rat and flounder renal type II Na+-Pi cotransporters.

    PubMed

    Forster, I C; Loo, D D; Eskandari, S

    1999-04-01

    The stoichiometry of the rat and flounder isoforms of the renal type II sodium-phosphate (Na+-Pi) cotransporter was determined directly by simultaneous measurements of phosphate (Pi)-induced inward current and uptake of radiolabeled Pi and Na+ in Xenopus laevis oocytes expressing the cotransporters. There was a direct correlation between the Pi-induced inward charge and Pi uptake into the oocytes; the slope indicated that one net inward charge was transported per Pi. There was also a direct correlation between the Pi-induced inward charge and Na+ influx; the slope indicated that the influx of three Na+ ions resulted in one net inward charge. This behavior was similar for both isoforms. We conclude that for both Na+-Pi cotransporter isoforms the Na+:Pi stoichiometry is 3:1 and that divalent Pi is the transported substrate. Steady-state activation of the currents showed that the Hill coefficients for Pi were unity for both isoforms, whereas for Na+, they were 1.8 (flounder) and 2.5 (rat). Therefore, despite significant differences in the apparent Na+ binding cooperativity, the estimated Na+:Pi stoichiometry was the same for both isoforms.

  18. Theoretical study of Na-atom emission from NaCl (100) surfaces

    NASA Astrophysics Data System (ADS)

    Puchin, Vladimir; Shluger, Alexander; Nakai, Yasuo; Itoh, Noriaki

    1994-04-01

    Several models for the elementary processes causing the emission of alkali atoms by electronic excitation of NaCl (100) surfaces have been investigated theoretically. First, the desorption of a Na atom neighboring an electronically excited F center on the surface is simulated using a quantum-mechanical embedded-cluster technique. It is shown that emission of a Na atom is energetically favorable. The kinetics of this process is shown to be controlled by the probability of a nonradiative transition between the two states: the excited state of the F center and that corresponding to a Na atom desorbing from the surface. The potential barrier for desorption of an excited Na atom from the excited F-center state is found to be 2.1 eV. It is also found that the energy for emission of a Na atom from a cluster of F centers (the F3 center) is considerably reduced (for a certain configuration of the defect) with respect to the similar energy for a single F center. The energy barrier for emission of a Na atom neighboring an F' center on the surface is calculated to be 1 eV. It is shown that the electronic excitation of kinklike sites, with a Na atom at the edge, can lead to a barrierless emission of a Na atom, leaving a Vk-type defect behind. The results of calculations are discussed critically on the basis of existing experimental data.

  19. Influence of sodium halides (NaF, NaCl, NaBr, NaI) on the photocatalytic performance of hydrothermally synthesized hematite photoanodes.

    PubMed

    Wang, Tsinghai; Huang, Mao-Chia; Hsieh, Yi-Kong; Chang, Wen-Sheng; Lin, Jing-Chie; Lee, Chih-Hao; Wang, Chu-Fang

    2013-08-28

    It has been suggested that a high concentration of Fe(3+) in solution, a low pH, and noncomplexing ions of high ionic strength are all essential for developing a high-quality hematite array. Our curiosity was piqued regarding the role of the electrolyte ions in the hydrothermal synthesis of hematite photoanodes. In this study, we prepared hematite photoanodes hydrothermally from precursor solutions of 0.1 M FeCl3 at pH 1.55 with a background electrolyte of 1.0 M sodium halide (NaF, NaCl, NaBr, or NaI). We compared the structures and properties of the as-obtained hematite photoanodes with those of the material prepared in 1.0 M NaNO3, the most widely adopted electrolyte in previous studies. Among our studied systems, we found that the hematite photoanode prepared in NaCl solution was the only one possessing properties similar to those of the sample obtained from the NaNO3 solution-most importantly in terms of photoelectrochemical performance (ca. 0.2 mA/cm(2) with +0.4 V vs SCE). The hematites obtained from the NaF, NaBr, and NaI solutions exhibited much lower (by approximately 2 orders of magnitude) photocurrent densities under the same conditions, possibly because of their relatively less ordered crystallinity and the absence of rodlike morphologies. Because the synthetic protocol was identical in each case, we believe that these two distinct features reflect the environments in which these hematite photoanodes were formed. Consistent with the latest studies reported in the literature of the X-ray photoelectron spectra of fast-frozen hematite colloids in aqueous solutions, it appears that the degree of surface ion loading at the electrolyte-hematite interface (Stern layer) is critical during the development of hematite photoanodes. We suspect that a lower ion surface loading benefits the hematite developing relatively higher-order and a rodlike texture, thereby improving the photoelectrochemical activity.

  20. Elastic Coulomb breakup of 34Na

    NASA Astrophysics Data System (ADS)

    Singh, G.; Shubhchintak, Chatterjee, R.

    2016-08-01

    Background: 34Na is conjectured to play an important role in the production of seed nuclei in the alternate r -process paths involving light neutron rich nuclei very near the β -stability line, and as such, it is important to know its ground state properties and structure to calculate rates of the reactions it might be involved in, in the stellar plasma. Found in the region of `island of inversion', its ground state might not be in agreement with normal shell model predictions. Purpose: The aim of this paper is to study the elastic Coulomb breakup of 34Na on 208Pb to give us a core of 33Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of 34Na. Method: A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of 34Na on 208Pb at 100 MeV/u. The triple differential cross section calculated for the breakup is integrated over the desired components to find the total cross-section, momentum, and angular distributions as well as the average momenta, along with the energy-angular distributions. Results: The total one neutron removal cross section is calculated to test the possible ground state configurations of 34Na. The average momentum results along with energy-angular calculations indicate 34Na to have a halo structure. The parallel momentum distributions with narrow full widths at half-maxima signify the same. Conclusion: We have attempted to analyze the possible ground state configurations of 34Na and in congruity with the patterns in the `island of inversion' conclude that even without deformation, 34Na should be a neutron halo with a predominant contribution to its ground state most probably coming from 33Na(3 /2+)⊗ 2 p3 /2ν configuration. We also surmise that it would certainly be useful and rewarding to test our

  1. Quasi-solid state rechargeable Na-CO2 batteries with reduced graphene oxide Na anodes.

    PubMed

    Hu, Xiaofei; Li, Zifan; Zhao, Yaran; Sun, Jianchao; Zhao, Qing; Wang, Jianbin; Tao, Zhanliang; Chen, Jun

    2017-02-01

    Na-CO2 batteries using earth-abundant Na and greenhouse gas CO2 are promising tools for mobile and stationary energy storage, but they still pose safety risks from leakage of liquid electrolyte and instability of the Na metal anode. These issues result in extremely harsh operating conditions of Na-CO2 batteries and increase the difficulty of scaling up this technology. We report the development of quasi-solid state Na-CO2 batteries with high safety using composite polymer electrolyte (CPE) and reduced graphene oxide (rGO) Na anodes. The CPE of PVDF-HFP [poly(vinylidene fluoride-co-hexafluoropropylene)]-4% SiO2/NaClO4-TEGDME (tetraethylene glycol dimethyl ether) has high ion conductivity (1.0 mS cm(-1)), robust toughness, a nonflammable matrix, and strong electrolyte-locking ability. In addition, the rGO-Na anode presents fast and nondendritic Na(+) plating/stripping (5.7 to 16.5 mA cm(-2)). The improved kinetics and safety enable the constructed rGO-Na/CPE/CO2 batteries to successfully cycle in wide CO2 partial pressure window (5 to 100%, simulated car exhaust) and especially to run for 400 cycles at 500 mA g(-1) with a fixed capacity of 1000 mA·hour g(-1) in pure CO2. Furthermore, we scaled up the reversible capacity to 1.1 A·hour in pouch-type batteries (20 × 20 cm, 10 g, 232 Wh kg(-1)). This study makes quasi-solid state Na-CO2 batteries an attractive prospect.

  2. Quasi–solid state rechargeable Na-CO2 batteries with reduced graphene oxide Na anodes

    PubMed Central

    Hu, Xiaofei; Li, Zifan; Zhao, Yaran; Sun, Jianchao; Zhao, Qing; Wang, Jianbin; Tao, Zhanliang; Chen, Jun

    2017-01-01

    Na-CO2 batteries using earth-abundant Na and greenhouse gas CO2 are promising tools for mobile and stationary energy storage, but they still pose safety risks from leakage of liquid electrolyte and instability of the Na metal anode. These issues result in extremely harsh operating conditions of Na-CO2 batteries and increase the difficulty of scaling up this technology. We report the development of quasi–solid state Na-CO2 batteries with high safety using composite polymer electrolyte (CPE) and reduced graphene oxide (rGO) Na anodes. The CPE of PVDF-HFP [poly(vinylidene fluoride-co-hexafluoropropylene)]–4% SiO2/NaClO4–TEGDME (tetraethylene glycol dimethyl ether) has high ion conductivity (1.0 mS cm−1), robust toughness, a nonflammable matrix, and strong electrolyte-locking ability. In addition, the rGO-Na anode presents fast and nondendritic Na+ plating/stripping (5.7 to 16.5 mA cm−2). The improved kinetics and safety enable the constructed rGO-Na/CPE/CO2 batteries to successfully cycle in wide CO2 partial pressure window (5 to 100%, simulated car exhaust) and especially to run for 400 cycles at 500 mA g−1 with a fixed capacity of 1000 mA·hour g−1 in pure CO2. Furthermore, we scaled up the reversible capacity to 1.1 A·hour in pouch-type batteries (20 × 20 cm, 10 g, 232 Wh kg−1). This study makes quasi–solid state Na-CO2 batteries an attractive prospect. PMID:28164158

  3. First discovery of Holocene cryptotephra in Amazonia

    PubMed Central

    Watson, Elizabeth J.; Swindles, Graeme T.; Savov, Ivan P.; Bacon, Karen L.

    2015-01-01

    The use of volcanic ash layers for dating and correlation (tephrochronology) is widely applied in the study of past environmental changes. We describe the first cryptotephra (non-visible volcanic ash horizon) to be identified in the Amazon basin, which is tentatively attributed to a source in the Ecuadorian Eastern Cordillera (0–1°S, 78-79°W), some 500-600 km away from our field site in the Peruvian Amazon. Our discovery 1) indicates that the Amazon basin has been subject to volcanic ash fallout during the recent past; 2) highlights the opportunities for using cryptotephras to date palaeoenvironmental records in the Amazon basin and 3) indicates that cryptotephra layers are preserved in a dynamic Amazonian peatland, suggesting that similar layers are likely to be present in other peat sequences that are important for palaeoenvironmental reconstruction. The discovery of cryptotephra in an Amazonian peatland provides a baseline for further investigation of Amazonian tephrochronology and the potential impacts of volcanism on vegetation. PMID:26493541

  4. Deforestation in Amazonia impacts riverine carbon dynamics

    NASA Astrophysics Data System (ADS)

    Langerwisch, Fanny; Walz, Ariane; Rammig, Anja; Tietjen, Britta; Thonicke, Kirsten; Cramer, Wolfgang

    2016-12-01

    Fluxes of organic and inorganic carbon within the Amazon basin are considerably controlled by annual flooding, which triggers the export of terrigenous organic material to the river and ultimately to the Atlantic Ocean. The amount of carbon imported to the river and the further conversion, transport and export of it depend on temperature, atmospheric CO2, terrestrial productivity and carbon storage, as well as discharge. Both terrestrial productivity and discharge are influenced by climate and land use change. The coupled LPJmL and RivCM model system (Langerwisch et al., 2016) has been applied to assess the combined impacts of climate and land use change on the Amazon riverine carbon dynamics. Vegetation dynamics (in LPJmL) as well as export and conversion of terrigenous carbon to and within the river (RivCM) are included. The model system has been applied for the years 1901 to 2099 under two deforestation scenarios and with climate forcing of three SRES emission scenarios, each for five climate models. We find that high deforestation (business-as-usual scenario) will strongly decrease (locally by up to 90 %) riverine particulate and dissolved organic carbon amount until the end of the current century. At the same time, increase in discharge leaves net carbon transport during the first decades of the century roughly unchanged only if a sufficient area is still forested. After 2050 the amount of transported carbon will decrease drastically. In contrast to that, increased temperature and atmospheric CO2 concentration determine the amount of riverine inorganic carbon stored in the Amazon basin. Higher atmospheric CO2 concentrations increase riverine inorganic carbon amount by up to 20 % (SRES A2). The changes in riverine carbon fluxes have direct effects on carbon export, either to the atmosphere via outgassing or to the Atlantic Ocean via discharge. The outgassed carbon will increase slightly in the Amazon basin, but can be regionally reduced by up to 60 % due to deforestation. The discharge of organic carbon to the ocean will be reduced by about 40 % under the most severe deforestation and climate change scenario. These changes would have local and regional consequences on the carbon balance and habitat characteristics in the Amazon basin itself as well as in the adjacent Atlantic Ocean.

  5. The phlebotomine sandflies of Venezuelan Amazonia.

    PubMed

    Feliciangeli, M D; Ramirez Perez, J; Ramirez, A

    1988-01-01

    Phlebotomine sandflies were surveyed in two ecologically contrasted areas, the northern moist and southern wet tropical forests, of the Territorio Federal Amazonas, Venezuela. Three new taxa and twenty-one new records were added to the previously known species list for Venezuelan sandflies, which now totals eighty species. Both sexes of Lutzomyia (Psychodopygus) killicki sp.n., L. (Trichophoryomyia) bettinii sp.n., L. (Nyssomyia) olmeca reducta subsp.n. and and the females of L. bernalei Osorno et al., Brumptomyia pintoi Costa Lima and L. begonae (Ortiz & Torres) are described and illustrated.

  6. Bilingual Education: An Experience in Peruvian Amazonia.

    ERIC Educational Resources Information Center

    Larson, Mildred L., Ed.; Davis, Patricia M., Ed.

    This book reports on an experimental bilingual education program conducted in Peru by Peruvian educators and Summer Institute of Linguistics (SIL) linguists. Sections of the book discuss: (1) the historical perspective of the program; (2) program aspects such as teacher training, goals, and curriculum; (3) what this program may contribute to the…

  7. Electrophysiological Determination of Submembrane Na(+) Concentration in Cardiac Myocytes.

    PubMed

    Hegyi, Bence; Bányász, Tamás; Shannon, Thomas R; Chen-Izu, Ye; Izu, Leighton T

    2016-09-20

    In the heart, Na(+) is a key modulator of the action potential, Ca(2+) homeostasis, energetics, and contractility. Because Na(+) currents and cotransport fluxes depend on the Na(+) concentration in the submembrane region, it is necessary to accurately estimate the submembrane Na(+) concentration ([Na(+)]sm). Current methods using Na(+)-sensitive fluorescent indicators or Na(+) -sensitive electrodes cannot measure [Na(+)]sm. However, electrophysiology methods are ideal for measuring [Na(+)]sm. In this article, we develop patch-clamp protocols and experimental conditions to determine the upper bound of [Na(+)]sm at the peak of action potential and its lower bound at the resting state. During the cardiac cycle, the value of [Na(+)]sm is constrained within these bounds. We conducted experiments in rabbit ventricular myocytes at body temperature and found that 1) at a low pacing frequency of 0.5 Hz, the upper and lower bounds converge at 9 mM, constraining the [Na(+)]sm value to ∼9 mM; 2) at 2 Hz pacing frequency, [Na(+)]sm is bounded between 9 mM at resting state and 11.5 mM; and 3) the cells can maintain [Na(+)]sm to the above values, despite changes in the pipette Na(+) concentration, showing autoregulation of Na(+) in beating cardiomyocytes.

  8. Voltage dependence of Na translocation by the Na/K pump.

    PubMed

    Nakao, M; Gadsby, D C

    During each complete reaction cycle, the Na/K pump transports three Na ions out across the cell membrane and two K ions in. The resulting net extrusion of positive charge generates outward membrane current but, until now, it was unclear how that net charge movement occurs. Reasonable possibilities included a single positive charge moving outwards during Na translocation; or a single negative charge moving inwards during K translocation; or either positive or negative charges moving during both translocation steps, but in unequal quantities. Any step that involves net charge movement through the membrane must have voltage-dependent transition rates. Here we report measurements of transient, voltage-dependent, displacement currents generated by the pump when its normal Na/K transport cycle has been interrupted by removal of external K and it is thus constrained to carry out Na/Na exchange. The quantity and voltage sensitivity of the charge moved during these transient currents suggests that Na translocation includes a voltage-dependent transition involving movement of one positive charge across the membrane. This single step can thus fully account for the electrogenic nature of Na/K exchange. The result provides important new insight into the molecular mechanism of active cation transport.

  9. Interaction of NaCl(g) and HCl(g) with condensed NA2SO4

    NASA Technical Reports Server (NTRS)

    Stearns, C. A.; Kohl, F. J.; Fryburg, G. C.; Miller, R. A.

    1977-01-01

    The interaction of Na2SO4(l) with NaCl(g), HCl(g) and H2O(g) was studied in atmospheric pressure flowing air and oxygen at Na2SO4(l) temperatures of 900 and 1000 C. Thermomicrogravimetric and high pressure mass spectrometric sampling techniques were used. Experimental results establish that previously reported enhanced rates of weight loss of Na2SO4(l) in the presence of NaCl(g) are due to the reaction: Na2SO4(c) + 2HCl(g) = 2NaCl(g) + SO2(g) + H2O(g) + 1/2O2(g) being driven to the right in flowing gas systems. The HCl(g) is the product of hydrolysis of NaCl caused by small but significant amounts of H2O(g) present in the system. Thermochemical calculations are used to show that even with sub-ppm levels of H2O(g) present, significant quantities of HCl(g) are produced.

  10. Dynamics of Na(+)(Benzene) + Benzene Association and Ensuing Na(+)(Benzene)2* Dissociation.

    PubMed

    Paul, Amit K; Kolakkandy, Sujitha; Hase, William L

    2015-07-16

    Chemical dynamics simulations were used to study Bz + Na(+)(Bz) → Na(+)(Bz)2* association and the ensuing dissociation of the Na(+)(Bz)2* cluster (Bz = benzene). An interesting and unexpected reaction found from the simulations is direct displacement, for which the colliding Bz molecule displaces the Bz molecule attached to Na(+), forming Na(+)(Bz). The rate constant for Bz + Na(+)(Bz) association was calculated at 750 and 1000 K, and found to decrease with increase in temperature. By contrast, the direct displacement rate constant increases with temperature. The cross section and rate constant for direct displacement are approximately an order of magnitude lower than those for association. The Na(+)(Bz)2* cluster, formed by association, dissociates with a biexponential probability, with the rate constant for the short-time component approximately an order of magnitude larger than that for the longer time component. The latter rate constant agrees with that of Rice-Ramsperger-Kassel-Marcus (RRKM) theory, consistent with rapid intramolecular vibrational energy redistribution (IVR) and intrinsic RRKM dynamics for the Na(+)(Bz)2* cluster. A coupled phase space model was used to analyze the biexponential dissociation probability.

  11. Low-affinity Na+ uptake in the halophyte Suaeda maritima.

    PubMed

    Wang, Suo-Min; Zhang, Jin-Lin; Flowers, Timothy J

    2007-10-01

    Na(+) uptake by plant roots has largely been explored using species that accumulate little Na(+) into their shoots. By way of contrast, the halophyte Suaeda maritima accumulates, without injury, concentrations of the order of 400 mM NaCl in its leaves. Here we report that cAMP and Ca(2+) (blockers of nonselective cation channels) and Li(+) (a competitive inhibitor of Na(+) uptake) did not have any significant effect on the uptake of Na(+) by the halophyte S. maritima when plants were in 25 or 150 mM NaCl (150 mM NaCl is near optimal for growth). However, the inhibitors of K(+) channels, TEA(+) (10 mM), Cs(+) (3 mM), and Ba(2+) (5 mM), significantly reduced the net uptake of Na(+) from 150 mM NaCl over 48 h, by 54%, 24%, and 29%, respectively. TEA(+) (10 mM), Cs(+) (3 mM), and Ba(2+) (1 mm) also significantly reduced (22)Na(+) influx (measured over 2 min in 150 mM external NaCl) by 47%, 30%, and 31%, respectively. In contrast to the situation in 150 mm NaCl, neither TEA(+) (1-10 mM) nor Cs(+) (0.5-10 mM) significantly reduced net Na(+) uptake or (22)Na(+) influx in 25 mM NaCl. Ba(2+) (at 5 mm) did significantly decrease net Na(+) uptake (by 47%) and (22)Na(+) influx (by 36% with 1 mM Ba(2+)) in 25 mM NaCl. K(+) (10 or 50 mM) had no effect on (22)Na(+) influx at concentrations below 75 mM NaCl, but the influx of (22)Na(+) was inhibited by 50 mM K(+) when the external concentration of NaCl was above 75 mM. The data suggest that neither nonselective cation channels nor a low-affinity cation transporter are major pathways for Na(+) entry into root cells. We propose that two distinct low-affinity Na(+) uptake pathways exist in S. maritima: Pathway 1 is insensitive to TEA(+) or Cs(+), but sensitive to Ba(2+) and mediates Na(+) uptake under low salinities (25 mM NaCl); pathway 2 is sensitive to TEA(+), Cs(+), and Ba(2+) and mediates Na(+) uptake under higher external salt concentrations (150 mM NaCl). Pathway 1 might be mediated by a high-affinity K transporter

  12. Anion-coupled Na efflux mediated by the human red blood cell Na/K pump

    SciTech Connect

    Dissing, S.; Hoffman, J.F. )

    1990-07-01

    The red cell Na/K pump is known to continue to extrude Na when both Na and K are removed from the external medium. Because this ouabain-sensitive flux occurs in the absence of an exchangeable cation, it is referred to as uncoupled Na efflux. This flux is also known to be inhibited by 5 mM Nao but to a lesser extent than that inhibitable by ouabain. Uncoupled Na efflux via the Na/K pump therefore can be divided into a Nao-sensitive and Nao-insensitive component. We used DIDS-treated, SO4-equilibrated human red blood cells suspended in HEPES-buffered (pHo 7.4) MgSO4 or (Tris)2SO4, in which we measured 22Na efflux, 35SO4 efflux, and changes in the membrane potential with the fluorescent dye, diS-C3 (5). A principal finding is that uncoupled Na efflux occurs electroneurally, in contrast to the pump's normal electrogenic operation when exchanging Nai for Ko. This electroneutral uncoupled efflux of Na was found to be balanced by an efflux of cellular anions. (We were unable to detect any ouabain-sensitive uptake of protons, measured in an unbuffered medium at pH 7.4 with a Radiometer pH-STAT.) The Nao-sensitive efflux of Nai was found to be 1.95 +/- 0.10 times the Nao-sensitive efflux of (SO4)i, indicating that the stoichiometry of this cotransport is two Na+ per SO4=, accounting for 60-80% of the electroneutral Na efflux. The remainder portion, that is, the ouabain-sensitive Nao-insensitive component, has been identified as PO4-coupled Na transport and is the subject of a separate paper. That uncoupled Na efflux occurs as a cotransport with anions is supported by the result, obtained with resealed ghosts, that when internal and external SO4 was substituted by the impermeant anion, tartrate i,o, the efflux of Na was inhibited 60-80%. This inhibition could be relieved by the inclusion, before DIDS treatment, of 5 mM Cli,o.

  13. A thermochemical explanation for the stability of NaCl3 and NaCl7

    NASA Astrophysics Data System (ADS)

    Fernandes de Farias, Robson

    2017-03-01

    Thermodynamically stable cubic and orthorhombic NaCl3 as well as NaCl7 have been synthesized (Zhang et al., 2013). In the present work, a thermochemical explanation for the stability of such unusual sodium chlorides is provided, based on lattice energy values. Using the Glasser-Jenkins generalized equation (Glasser and Jenkins, 2000) lattice energies (kJ mol-1) of -162.5, -168.9 and -113.1 are calculated for Pm3n NaCl3, Pnma NaCl3 and NaCl7, respectively. It is postulated that any NaxCly compound could be synthesized, if the ionic character of the Nasbnd Cl bond in the prepared compound remains around 80%, and the sodium charge below unit.

  14. Changes in Intracellular Na+ following Enhancement of Late Na+ Current in Virtual Human Ventricular Myocytes.

    PubMed

    Cardona, Karen; Trenor, Beatriz; Giles, Wayne R

    2016-01-01

    The slowly inactivating or late Na+ current, INa-L, can contribute to the initiation of both atrial and ventricular rhythm disturbances in the human heart. However, the cellular and molecular mechanisms that underlie these pro-arrhythmic influences are not fully understood. At present, the major working hypothesis is that the Na+ influx corresponding to INa-L significantly increases intracellular Na+, [Na+]i; and the resulting reduction in the electrochemical driving force for Na+ reduces and (may reverse) Na+/Ca2+ exchange. These changes increase intracellular Ca2+, [Ca2+]i; which may further enhance INa-L due to calmodulin-dependent phosphorylation of the Na+ channels. This paper is based on mathematical simulations using the O'Hara et al (2011) model of baseline or healthy human ventricular action potential waveforms(s) and its [Ca2+]i homeostasis mechanisms. Somewhat surprisingly, our results reveal only very small changes (≤ 1.5 mM) in [Na+]i even when INa-L is increased 5-fold and steady-state stimulation rate is approximately 2 times the normal human heart rate (i.e. 2 Hz). Previous work done using well-established models of the rabbit and human ventricular action potential in heart failure settings also reported little or no change in [Na+]i when INa-L was increased. Based on our simulations, the major short-term effect of markedly augmenting INa-L is a significant prolongation of the action potential and an associated increase in the likelihood of reactivation of the L-type Ca2+ current, ICa-L. Furthermore, this action potential prolongation does not contribute to [Na+]i increase.

  15. Changes in Intracellular Na+ following Enhancement of Late Na+ Current in Virtual Human Ventricular Myocytes

    PubMed Central

    Giles, Wayne R.

    2016-01-01

    The slowly inactivating or late Na+ current, INa-L, can contribute to the initiation of both atrial and ventricular rhythm disturbances in the human heart. However, the cellular and molecular mechanisms that underlie these pro-arrhythmic influences are not fully understood. At present, the major working hypothesis is that the Na+ influx corresponding to INa-L significantly increases intracellular Na+, [Na+]i; and the resulting reduction in the electrochemical driving force for Na+ reduces and (may reverse) Na+/Ca2+ exchange. These changes increase intracellular Ca2+, [Ca2+]i; which may further enhance INa-L due to calmodulin-dependent phosphorylation of the Na+ channels. This paper is based on mathematical simulations using the O’Hara et al (2011) model of baseline or healthy human ventricular action potential waveforms(s) and its [Ca2+]i homeostasis mechanisms. Somewhat surprisingly, our results reveal only very small changes (≤ 1.5 mM) in [Na+]i even when INa-L is increased 5-fold and steady-state stimulation rate is approximately 2 times the normal human heart rate (i.e. 2 Hz). Previous work done using well-established models of the rabbit and human ventricular action potential in heart failure settings also reported little or no change in [Na+]i when INa-L was increased. Based on our simulations, the major short-term effect of markedly augmenting INa-L is a significant prolongation of the action potential and an associated increase in the likelihood of reactivation of the L-type Ca2+ current, ICa-L. Furthermore, this action potential prolongation does not contribute to [Na+]i increase. PMID:27875582

  16. Targeting voltage gated sodium channels NaV1.7, Na V1.8, and Na V1.9 for treatment of pathological cough.

    PubMed

    Muroi, Yukiko; Undem, Bradley J

    2014-02-01

    Recent advances in our understanding of voltage-gated sodium channels (NaVs) lead to the rational hypothesis that drugs capable of selective blockade of NaV subtypes may be a safe and effective strategy for the treatment of unwanted cough. Among the nine NaV subtypes (NaV1.1-NaV1.9), the afferent nerves involved in initiating cough, in common with nociceptive neurons in the somatosensory system, express mainly NaV1.7, NaV1.8, and NaV1.9. Although knowledge about the effect of selectively blocking these channels on the cough reflex is limited, their biophysical properties indicate that each may contribute to the hypertussive and allotussive state that typifies subacute and chronic nonproductive cough.

  17. Intracellular [Na+], Na+ pathways, and fluid transport in cultured bovine corneal endothelial cells.

    PubMed

    Kuang, Kunyan; Li, Yansui; Yiming, Maimaiti; Sánchez, José M; Iserovich, Pavel; Cragoe, E J; Diecke, Friedrich P J; Fischbarg, Jorge

    2004-07-01

    The mechanism of fluid transport across corneal endothelium remains unclear. We examine here the relative contributions of cellular mechanisms of Na+ transport and the homeostasis of intracellular [Na+] in cultured bovine corneal endothelial cells, and the influence of ambient Na+ and HCO3- on the deturgescence of rabbit cornea. Bovine corneal endothelial cells plated on glass coverslips were incubated for 60 min with 10 microm of the fluorescent Na+ indicator SBFI precursor in HCO3- HEPES (BH) Ringer's solution. After loading, cells were placed in a perfusion chamber. Indicator fluorescence (490 nm) was determined with a Chance-Legallais time-sharing fluorometer. Its voltage output was the ratio of the emissions excited at 340 and 380 nm. For calibration, cells were treated with gramicidin D. For fluid transport measurements, rabbit corneas were mounted in a Dikstein-Maurice chamber, and stromal thickness was measured with a specular microscope. The steady-state [Na+]i in BH was 14.36+/-0.38 mM (n = mean+/-s.e.). Upon exposure to Na+ -free BH solution (choline substituted), [Na+]i decreased to 1.81+/-0.20mM (n = 19). When going from Na+ -free plus 100 microm ouabain to BH plus ouabain, [Na+]i increased to 46.17+/-2.50 (n = 6) with a half time of 1.26+/-0.04 min; if 0.1 microm phenamil plus ouabain were present, it reached only 21.78+/-1.50mm. The exponential time constants (min-1) were: 0.56+/-0.04 for the Na+ pump; 0.39+/-0.01 for the phenamil sensitive Na+ channel; and 0.17+/-0.02 for the ouabain-phenamil-insensitive pathways. In HCO3- free medium (gluconate substituted), [Na+]i was 14.03+/-0.11mM; upon changing to BH medium, it increased to 30.77+/-0.74 mm. This last [Na+]i increase was inhibited 66% by 100 microm DIDS. Using BH medium, corneal thickness remained nearly constant, increasing at a rate of only 2.9+/-0.9 microm hr-1 during 3 hr. However, stromal thickness increased drastically (swelling rate 36.1+/-2.6 microm hr-1) in corneas superfused with BH

  18. Compact clinical high-NA multiphoton endoscopy

    NASA Astrophysics Data System (ADS)

    Weinigel, Martin; Breunig, Hans Georg; Fischer, Peter; Kellner-Höfer, Marcel; Bückle, Rainer; König, Karsten

    2012-02-01

    Multiphoton imaging methods are excellent for non-invasive imaging of living tissue without any need of additional contrast agents. The increasing demand for endoscopic techniques has forced the development of multiphoton endoscopes for imaging of areas with reduced accessibility like chronic wounds. Gradient index (GRIN) lenses can miniaturize the bulky distal focusing optics of conventional tomographs to a diameter of less than 1.4 mm and a numerical aperture (NA) of 0.8. We combined a high NA clinical multiphoton endoscope with existing multiphoton tomographs like the DermaInspect® and the MPTflex® to enable the examination of wound healing processes.

  19. Sodium-difluoro(oxalato)borate (NaDFOB): a new electrolyte salt for Na-ion batteries.

    PubMed

    Chen, Juner; Huang, Zhenguo; Wang, Caiyun; Porter, Spencer; Wang, Baofeng; Lie, Wilford; Liu, Hua Kun

    2015-06-18

    A new electrolyte salt, sodium-difluoro(oxalato)borate (NaDFOB), was synthesized and studied, which enables excellent reversible capacity and high rate capability when used in Na/Na0.44MnO2 half cells. NaDFOB has excellent compatibility with various common solvents used in Na-ion batteries, in strong contrast to the solvent dependent performances of NaClO4 and NaPF6. In addition, NaDFOB possesses good stability and generates no toxic or dangerous products when exposed to air and water. All these properties demonstrate that NaDFOB could be used to prepare high performance electrolytes for emerging Na-ion batteries.

  20. Role of the Na(+)-translocating NADH:quinone oxidoreductase in voltage generation and Na(+) extrusion in Vibrio cholerae.

    PubMed

    Vorburger, Thomas; Nedielkov, Ruslan; Brosig, Alexander; Bok, Eva; Schunke, Emina; Steffen, Wojtek; Mayer, Sonja; Götz, Friedrich; Möller, Heiko M; Steuber, Julia

    2016-04-01

    For Vibrio cholerae, the coordinated import and export of Na(+) is crucial for adaptation to habitats with different osmolarities. We investigated the Na(+)-extruding branch of the sodium cycle in this human pathogen by in vivo (23)Na-NMR spectroscopy. The Na(+) extrusion activity of cells was monitored after adding glucose which stimulated respiration via the Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR). In a V. cholerae deletion mutant devoid of the Na(+)-NQR encoding genes (nqrA-F), rates of respiratory Na(+) extrusion were decreased by a factor of four, but the cytoplasmic Na(+) concentration was essentially unchanged. Furthermore, the mutant was impaired in formation of transmembrane voltage (ΔΨ, inside negative) and did not grow under hypoosmotic conditions at pH8.2 or above. This growth defect could be complemented by transformation with the plasmid encoded nqr operon. In an alkaline environment, Na(+)/H(+) antiporters acidify the cytoplasm at the expense of the transmembrane voltage. It is proposed that, at alkaline pH and limiting Na(+) concentrations, the Na(+)-NQR is crucial for generation of a transmembrane voltage to drive the import of H(+) by electrogenic Na(+)/H(+) antiporters. Our study provides the basis to understand the role of the Na(+)-NQR in pathogenicity of V. cholerae and other pathogens relying on this primary Na(+) pump for respiration.

  1. Electronic Polarisability of NaNO2-NaNO3 and NaOH-NaNO3 Ionic Melts and Effective Ionic Radius of OH-

    NASA Astrophysics Data System (ADS)

    Iwadate, Yasuhiko; Ohnishi, Ryosuke; Ohkubo, Takahiro

    2017-01-01

    Molar volumes and refractive indexes of molten NaNO2-NaNO3 and NaOH-NaNO3 systems were measured by dilatometry and goniometry, respectively. The molar volumes of both systems increased with increasing temperature. Refractive indexes decreased with a rise of temperature or with increasing wavelength of the incident visible light. Assuming that the electronic polarisability is inherent in an ion, the electronic polarisability of a OH- ion in the melt was estimated from the Lorentz-Lorenz equation to be 1.26×10-30 m3, being comparable with that in the crystal. The effective ionic radius of a OH- ion was evaluated from the obtained electronic polarisability to be 1.34×10-10 m, using the correlation between the third power of the ionic radius and the electronic polarisability of an ion so far reported. The effective ionic radius obtained in this work was in good agreement with that assigned by Shannon.

  2. Recent results and prospects from NA62

    NASA Astrophysics Data System (ADS)

    Bizzeti, Andrea

    2016-11-01

    A large sample of charged kaon decays in 2007 has been collected by the NA62 experiment at CERN SPS using the experimental setup of the former NA48 experiment. Its intense kaon beam provides an abundant source of tagged neutral pions in vacuum. A measurement of the electromagnetic transition form factor slope of the neutral pion from 1:05 × 106 fully reconstructed π0 Dalitz decays is presented. The obtained preliminary value a = (3.70 ± 0.53stat ± 0.36syst) × 10-2 is the first 5.8σ observation of a non-zero slope in the time-like region of momentum transfer. K+ → π+ vv¯ is a theoretically very clean decay where indirect effects of new physics may be detectable. The NA62 apparatus has been significantly upgraded between 2008 and 2014 in order to measure the branching ratio of this decay with 10% precision. The NA62 experiment took data with the new setup in pilot runs in 2014 and 2015, reaching the design beam intensity. Results of first data quality studies in view of the 2016-2017 physics runs are presented.

  3. Light-induced drift of Na atoms

    NASA Astrophysics Data System (ADS)

    Werij, H. G. C.; Woerdman, J. P.

    1988-10-01

    Light can induce a flux of optically absorbing particles immersed in a buffer gas, when these particles have a different mobility in the ground and excited state. This paper presents a study of light-induced drift (LID) of Na atoms in noble gases, which can be regarded as the “canonical” system for experiments in this field. We have experimentally studied the LID effect in the optically thin and the optically thick regimes. Parameters which have been varied are laser frequency, laser intensity, buffer gas pressure and buffer gas species. This work gives the first critical comparison of LID experiments with realistic theory in which the multilevel complications of the Na atom have been incorporated. In the optically thick case (“optical piston”) one can distinguish the open cell and the closed cell regimes. Effects of adsorption and desorption of Na atoms at the surface of the cell wall have been incorporated into the theory. The experimental data are in excellent agreement with the results of a four-level rate-equation model for LID which incorporates the fine and hyperfine structure of the level scheme of the Na absorbers.

  4. Mechanisms contributing to the cardiac inotropic effect of Na pump inhibition and reduction of extracellular Na

    PubMed Central

    1987-01-01

    Reduction of the transsarcolemmal [Na] gradient in rabbit cardiac muscle leads to an increase in the force of contraction. This has frequently been attributed to alteration of Ca movements via the sarcolemmal Na/Ca exchange system. However, the specific mechanisms that mediate the increased force at individual contractions have not been clearly established. In the present study, the [Na] gradient was decreased by reduction of extracellular [Na] or inhibition of the Na pump by either the cardioactive steroid acetylstrophanthidin or by reduction of extracellular [K]. Contractile performance and changes in extracellular Ca (sensed by double-barreled Ca-selective microelectrodes) were studied in order to elucidate the underlying basis for the increase in force. In the presence of agents that inhibit sarcoplasmic reticulum (SR) function (10 mM caffeine, 100-500 nM ryanodine), reduction of the [Na] gradient produced increases in contractile force similar to that observed in the absence of caffeine or ryanodine. It is concluded that an intact, functioning SR is not required for the inotropic effect of [Na] gradient reduction (at least in rabbit ventricle). However, this does not exclude a possible contribution of enhanced SR Ca release in the inotropic response to [Na] gradient reduction in the absence of caffeine or ryanodine. Acetylstrophanthidin (3-5 microM) usually leads to an increase in the magnitude of extracellular Ca depletions associated with individual contractions. However, acetylstrophanthidin can also increase extracellular Ca accumulation during the contraction, especially at potentiated contractions. This extracellular Ca accumulation can be suppressed by ryanodine and it is suggested that this apparent enhancement of Ca efflux is secondary to an enhanced release of Ca from the SR. Under conditions where Ca efflux during contractions is minimized (after a rest interval in the presence of ryanodine), acetylstrophanthidin increased both the rate and the

  5. Intracellular Na(+) and metabolic modulation of Na/K pump and excitability in the rat suprachiasmatic nucleus neurons.

    PubMed

    Wang, Yi-Chi; Yang, Jyh-Jeen; Huang, Rong-Chi

    2012-10-01

    Na/K pump activity and metabolic rate are both higher during the day in the suprachiasmatic nucleus (SCN) that houses the circadian clock. Here we investigated the role of intracellular Na(+) and energy metabolism in regulating Na/K pump activity and neuronal excitability. Removal of extracellular K(+) to block the Na/K pump excited SCN neurons to fire at higher rates and return to normal K(+) to reactivate the pump produced rebound hyperpolarization to inhibit firing. In the presence of tetrodotoxin to block the action potentials, both zero K(+)-induced depolarization and rebound hyperpolarization were blocked by the cardiac glycoside strophanthidin. Ratiometric Na(+) imaging with a Na(+)-sensitive fluorescent dye indicated saturating accumulation of intracellular Na(+) in response to pump blockade with zero K(+). The Na(+) ionophore monensin also induced Na(+) loading and hyperpolarized the membrane potential, with the hyperpolarizing effect of monensin abolished in zero Na(+) or by pump blockade. Conversely, Na(+) depletion with Na(+)-free pipette solution depolarized membrane potential but retained residual Na/K pump activity. Cyanide inhibition of oxidative phosphorylation blocked the Na/K pump to depolarize resting potential and increase spontaneous firing in most cells, and to raise intracellular Na(+) levels in all cells. Nonetheless, the Na/K pump was incompletely blocked by cyanide but completely blocked by iodoacetate to inhibit glycolysis, indicating the involvement of both oxidative phosphorylation and glycolysis in fueling the Na/K pump. Together, the results indicate the importance of intracellular Na(+) and energy metabolism in regulating Na/K pump activity as well as neuronal excitability in the SCN neurons.

  6. [Regulation of the Na/Ca exchanger].

    PubMed

    DiPolo, R; Rojas, H; Beaugé, L

    1993-01-01

    The introduction of the squid giant axon preparation to studies on Ca homeostasis has proven very useful in laying the foundations in the study of Ca regulation. In particular the Na/Ca exchange mechanism has been characterized in terms of its regulatory processes using the well define technique of intracellular dialysis and membrane potential control. The Na/Ca exchange countertransport system plays a critical role in physiological processes including cardiac contractility and photoreception. It has also been implicate in the etiology of essential hypertension, cardiac arrhythmias and cell death. The ability of the Na/Ca exchanger to regulate the intracellular ionized Ca concentration ([Ca2+i]) under physiological conditions, is determined by the direction (net Ca efflux or Ca influx), and magnitude of transport. The direction of Ca transport is decided by the chemical gradient of sodium and calcium. The magnitude of the exchange is regulated by kinetic factors. This kinetic factors are critical since they decide whether the exchanger will mediate a net Ca movement under certain conditions. Recently, a large effort has been put together to characterize the secondary modulation of the Na/Ca exchanger. In particular modulation by MgATP and intracellular Ca2+. In nerve cells we have discover that MgATP regulates the exchanger through as phosphorylation-dephosphorylation processes most probably relate to the action of a kinase-phosphatase system. The other important ligand that regulates the exchange activity is the level of [Ca2+i]. We have found the presence of a regulatory site in the cytoplasmic face of the exchanger different from the transport site and probably responsible for turning the carrier "on" or "off". In this article we will depict some of the processes involved in the metabolic and ionic regulation of the Na/Ca exchanger.

  7. Laser trapping of {sup 21}Na atoms

    SciTech Connect

    Lu, Zheng-Tian

    1994-09-01

    This thesis describes an experiment in which about four thousand radioactive {sup 21}Na (t{sub l/2} = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped {sup 21}Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of {sup 21}Na {yields} {sup 21}Ne + {Beta}{sup +} + v{sub e}, which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trapped atoms that we have achieved is still about two orders of magnitude lower than what is needed to conduct a measurement of the beta-asymmetry parameter at 1% of precision level, the result of this experiment proved the feasibility of trapping short-lived radioactive atoms. In this experiment, {sup 21}Na atoms were produced by bombarding {sup 24}Mg with protons of 25 MeV at the 88 in. Cyclotron of Lawrence Berkeley Laboratory. A few recently developed techniques of laser manipulation of neutral atoms were applied in this experiment. The {sup 21}Na atoms emerging from a heated oven were first transversely cooled. As a result, the on-axis atomic beam intensity was increased by a factor of 16. The atoms in the beam were then slowed down from thermal speed by applying Zeeman-tuned slowing technique, and subsequently loaded into a magneto-optical trap at the end of the slowing path. The last two chapters of this thesis present two studies on the magneto-optical trap of sodium atoms. In particular, the mechanisms of magneto-optical traps at various laser frequencies and the collisional loss mechanisms of these traps were examined.

  8. The Na4(+3) Clusters in Sodium Sodalite

    DTIC Science & Technology

    1992-05-15

    ATES COVOIN0i-15-92 Technical 06-01-91 to 05-31-92 4. TITLE ANA SUGTITLE S. RNORNG NUMBER The Na4+ 3 Clusters in Sodium Sodalite NN l14-e0-J-se59a 𔄀...3 [AlSiO 4]3 sodalite prepared by high vacuum deposition of sodium atoms. The samples with a Na 43 +:Na33+ cluster ratio up to 1:10 show a single...absorption feature with -m. = 628 nm (1.99 eV). The absorption originates from the individual sodalite cages containing Na 43+ cluster. For the Na 43+:Na

  9. The solubility of Cr(OH){sub 3}(am) in concentrated NaOH and NaOH-NaNO{sub 3} solutions

    SciTech Connect

    Felmy, A.R.; Rai, D.; Fulton, R.W.

    1994-08-01

    Chromium is a major component of the Hanford waste tank sludges, and the presence of Cr in the sludges is a significant concern in the disposal of these sludges because Cr can interfere with the formation of waste glasses. One of the current pretreatment strategies for removing constituents that can interfere with glass formation, such as P and Cr, is to wash/dissolve the sludges in basic NaOH solutions. The solubility of Cr(OH){sub 3}(am) was measured in concentrated NaOH ranging in concentration from 0.1M to 6.0M and in NaOH-NaNO{sub 3} solutions with fixed NaOH concentration and variable NaNO{sub 3} concentration at room temperature (22--23 C). Equilibrium between solids and solutions was approached relatively slowly and required approximately 60--70 days before steady-state concentrations were reached. A thermodynamic model, based upon the Pitzer equations, was developed from the solubility data in NaOH, which includes only two aqueous Cr species (Cr(OH){sub 4}{sup {minus}} and NaCr(OH){sub 4}(aq)) and ion-interaction parameters for Na{sup +} with Cr(OH){sub 4}{sup {minus}}. This model was then tested in the mixed NaOH-NaNO{sub 3} solutions and found to be reliable.

  10. Effects of non-uniform root zone salinity on water use, Na+ recirculation, and Na+ and H+ flux in cotton.

    PubMed

    Kong, Xiangqiang; Luo, Zhen; Dong, Hezhong; Eneji, A Egrinya; Li, Weijiang

    2012-03-01

    A new split-root system was established through grafting to study cotton response to non-uniform salinity. Each root half was treated with either uniform (100/100 mM) or non-uniform NaCl concentrations (0/200 and 50/150 mM). In contrast to uniform control, non-uniform salinity treatment improved plant growth and water use, with more water absorbed from the non- and low salinity side. Non-uniform treatments decreased Na(+) concentrations in leaves. The [Na(+)] in the '0' side roots of the 0/200 treatment was significantly higher than that in either side of the 0/0 control, but greatly decreased when the '0' side phloem was girdled, suggesting that the increased [Na(+)] in the '0' side roots was possibly due to transportation of foliar Na(+) to roots through phloem. Plants under non-uniform salinity extruded more Na(+) from the root than those under uniform salinity. Root Na(+) efflux in the low salinity side was greatly enhanced by the higher salinity side. NaCl-induced Na(+) efflux and H(+) influx were inhibited by amiloride and sodium orthovanadate, suggesting that root Na(+) extrusion was probably due to active Na(+)/H(+) antiport across the plasma membrane. Improved plant growth under non-uniform salinity was thus attributed to increased water use, reduced leaf Na(+) concentration, transport of excessive foliar Na(+) to the low salinity side, and enhanced Na(+) efflux from the low salinity root.

  11. Synthesis of Na-A and/or Na-X zeolite/porous carbon composites from carbonized rice husk

    NASA Astrophysics Data System (ADS)

    Katsuki, Hiroaki; Komarneni, Sridhar

    2009-07-01

    Na-A and/or Na-X zeolite/porous carbon composites were prepared under hydrothermal conditions by NaOH dissolution of silica first from carbonized rice husk followed by addition of NaAlO 2 and in situ crystallization of zeolites i.e., using a two-step process. When a one-step process was used, both Na-A and Na-X zeolites crystallized on the surface of carbon. Na-A or Na-X zeolite crystals were prepared on the porous carbonized rice husk at 90 °C for 2-6 h by changing the SiO 2/Al 2O 3, H 2O/Na 2O and Na 2O/SiO 2 molar ratios of precursors in the two-step process. The surface area and NH 4+-cation exchange capacity (CEC) of Na-A zeolite/porous carbon were found to be 171 m 2/g and 506 meq/100 g, respectively, while those of Na-X zeolite/porous carbon composites were 676 m 2/g and 317 meq/100 g, respectively. Na-A and Na-X zeolites are well-known microporous and hydrophilic materials while carbonized rice husk was found to be mesoporous (pores of ˜3.9 nm) and hydrophobic. These hybrid microporous-mesoporous and hydrophilic-hydrophobic composites are expected to be useful for decontamination of metal cations as well as organic contaminants simultaneously.

  12. Regulation of cardiac myocyte contractility by phospholemman: Na+/Ca2+ exchange versus Na+ -K+ -ATPase.

    PubMed

    Song, Jianliang; Zhang, Xue-Qian; Wang, JuFang; Cheskis, Ellina; Chan, Tung O; Feldman, Arthur M; Tucker, Amy L; Cheung, Joseph Y

    2008-10-01

    Phospholemman (PLM) regulates cardiac Na(+)/Ca(2+) exchanger (NCX1) and Na(+)-K(+)-ATPase in cardiac myocytes. PLM, when phosphorylated at Ser(68), disinhibits Na(+)-K(+)-ATPase but inhibits NCX1. PLM regulates cardiac contractility by modulating Na(+)-K(+)-ATPase and/or NCX1. In this study, we first demonstrated that adult mouse cardiac myocytes cultured for 48 h had normal surface membrane areas, t-tubules, and NCX1 and sarco(endo)plasmic reticulum Ca(2+)-ATPase levels, and retained near normal contractility, but alpha(1)-subunit of Na(+)-K(+)-ATPase was slightly decreased. Differences in contractility between myocytes isolated from wild-type (WT) and PLM knockout (KO) hearts were preserved after 48 h of culture. Infection with adenovirus expressing green fluorescent protein (GFP) did not affect contractility at 48 h. When WT PLM was overexpressed in PLM KO myocytes, contractility and cytosolic Ca(2+) concentration ([Ca(2+)](i)) transients reverted back to those observed in cultured WT myocytes. Both Na(+)-K(+)-ATPase current (I(pump)) and Na(+)/Ca(2+) exchange current (I(NaCa)) in PLM KO myocytes rescued with WT PLM were depressed compared with PLM KO myocytes. Overexpressing the PLMS68E mutant (phosphomimetic) in PLM KO myocytes resulted in the suppression of I(NaCa) but had no effect on I(pump). Contractility, [Ca(2+)](i) transient amplitudes, and sarcoplasmic reticulum Ca(2+) contents in PLM KO myocytes overexpressing the PLMS68E mutant were depressed compared with PLM KO myocytes overexpressing GFP. Overexpressing the PLMS68A mutant (mimicking unphosphorylated PLM) in PLM KO myocytes had no effect on I(NaCa) but decreased I(pump). Contractility, [Ca(2+)](i) transient amplitudes, and sarcoplasmic reticulum Ca(2+) contents in PLM KO myocytes overexpressing the S68A mutant were similar to PLM KO myocytes overexpressing GFP. We conclude that at the single-myocyte level, PLM affects cardiac contractility and [Ca(2+)](i) homeostasis primarily by its direct

  13. Na/beta-alumina/NaAlCl4, Cl2/C circulating cell

    NASA Astrophysics Data System (ADS)

    Cherng, Jing-Yih; Bennion, Douglas N.

    1987-09-01

    A study was made of a high specific energy battery based on a sodium negative electrode and a chlorine positive electrode with molten AlCl3-NaCl electrolyte and a solid beta alumina separator. The basic performance of a Na beta-alumina NaAlCl4, Cl2/C circulating cell at 200 C was demonstrated. This cell can be started at 150 C. The use of melting sodium chloroaluminate electrolyte overcomes some of the material problems associated with the high working temperatures of present molten salt systems, such as Na/S and LiAl/FeS, and retains the advantages of high energy density and relatively efficient electrode processes. Preliminary investigations were conducted on a sodium-chlorine static cell, material compability, electrode design, wetting, and theoretical calculations to assure a better chance of success before assembling a Na/Cl2 circulating cell. Mathematical models provide a theoretical explanation for the performance of the NaCl2 battery. The results of mathematical models match the experimental results very well. According to the result of the mathematical modeling, an output at 180 mA/sq cm and 3.2 V can be obtained with optimized cell design.

  14. Final-state symmetry of Na 1s core-shell excitons in NaCl and NaF

    SciTech Connect

    Nagle, K.P.; Seidler, G.T.; Shirley, E.L.; Fister, T.T.; Bradley, J.A.; Brown, F.C.

    2009-08-13

    We report measurements of the Na 1s contribution to the nonresonant inelastic x-ray scattering (NRIXS) from NaCl and NaF. Prior x-ray absorption studies have observed two pre-edge excitons in both materials. The momentum-transfer dependence (q dependence) of the measured NRIXS cross section and of real-space full multiple scattering and Bethe-Salpeter calculations determine that the higher-energy core excitons are s type for each material. The lower-energy core excitons contribute at most weakly to the NRIXS signal and we propose that these may be surface core excitons, as have been observed in several other alkali halides. The analysis of the orbital angular momentum of these features leads to a discussion of the limited sensitivity of NRIXS measurements to d-type final states when investigating 1s initial states. In this case the s- and p-type final density of states can be characterized by measurements at a small number of momentum transfers. This is in contrast to the case of more complex initial states for which measurements at a large number of momentum transfers are needed to separate the rich admixture of accessible and contributing final-state symmetries.

  15. Computational interpretation of 23Na MQMAS NMR spectra: A comprehensive investigation of the Na environment in silicate glasses

    NASA Astrophysics Data System (ADS)

    Gambuzzi, Elisa; Charpentier, Thibault; Menziani, Maria Cristina; Pedone, Alfonso

    2014-09-01

    Molecular dynamics, density functional theory calculations and 23Na NMR experiments have been used to inspect the chemical and structural characteristics of the Na environment in soda-lime silicate (CSN) and aluminosilicate (CASN) glasses. The use of an improved 3QMAS pulse sequence has allowed a clear identification of different Na sites. Average coordination numbers have been extracted by fitting the 23Na 3QMAS spectra with the computed NMR parameters. The results show that the 23Na δiso values correlate with the average <Na-O> distances only when the different coordination numbers are explicitly taken into account.

  16. Elementary immunology: Na(+) as a regulator of immunity.

    PubMed

    Schatz, Valentin; Neubert, Patrick; Schröder, Agnes; Binger, Katrina; Gebhard, Matthias; Müller, Dominik N; Luft, Friedrich C; Titze, Jens; Jantsch, Jonathan

    2017-02-01

    The skin can serve as an interstitial Na(+) reservoir. Local tissue Na(+) accumulation increases with age, inflammation and infection. This increased local Na(+) availability favors pro-inflammatory immune cell function and dampens their anti-inflammatory capacity. In this review, we summarize available data on how NaCl affects various immune cells. We particularly focus on how salt promotes pro-inflammatory macrophage and T cell function and simultaneously curtails their regulatory and anti-inflammatory potential. Overall, these findings demonstrate that local Na(+) availability is a promising novel regulator of immunity. Hence, the modulation of tissue Na(+) levels bears broad therapeutic potential: increasing local Na(+) availability may help in treating infections, while lowering tissue Na(+) levels may be used to treat, for example, autoimmune and cardiovascular diseases.

  17. Mechanisms and regulation of Na(+) uptake by freshwater fish.

    PubMed

    Kumai, Yusuke; Perry, Steve F

    2012-12-01

    Mechanisms of ion uptake by freshwater (FW) fish have received considerable attention over the past 80 years. Through an assortment of techniques incorporating whole animal physiology, electrophysiology and molecular biological approaches, three models have been proposed to account for Na(+) uptake. (1) Direct exchange of Na(+) and H(+) via one or more types of Na(+)/H(+) exchanger (slc9), (2) uptake of Na(+) through epithelial Na(+) channels energized by an electrical gradient created by H(+)-ATPase and (3) Na(+)/Cl(-) co-transport (slc12). While each mechanism is supported at least in part by theoretical or experimental data, there are several outstanding questions that have not yet been fully resolved. Furthermore, there are few details concerning how these Na(+) uptake mechanisms are fine tuned in response to the fluctuating FW environments. In this review, we summarize the current understanding of these three Na(+) uptake mechanisms and discuss their regulation by endocrine (cortisol and prolactin) and neurohumoral (catecholamines) factors.

  18. An enhancement to the NA4 gear vibration diagnostic parameter

    NASA Technical Reports Server (NTRS)

    Decker, Harry J.; Handschuh, Robert F.; Zakrajsek, James J.

    1994-01-01

    A new vibration diagnostic parameter for health monitoring of gears, NA4*, is proposed and tested. A recently developed gear vibration diagnostic parameter NA4 outperformed other fault detection methods at indicating the start and initial progression of damage. However, in some cases, as the damage progressed, the sensitivity of the NA4 and FM4 parameters tended to decrease and no longer indicated damage. A new parameter, NA4* was developed by enhancing NA4 to improve the trending of the parameter. This allows for the indication of damage both at initiation and also as the damage progresses. The NA4* parameter was verified and compared to the NA4 and FM4 parameters using experimental data from single mesh spur and spiral bevel gear fatigue rigs. The primary failure mode for the test cases was naturally occurring tooth surface pitting. The NA4* parameter is shown to be a more robust indicator of damage.

  19. U. S. EPA’S NA APPROACH FOR PETROLEUM HYDROCARBONS

    EPA Science Inventory

    Most evaluations of NA of petroleum hydrocarbons use geochemical data to document the NA through biodegradation. The expected trends during biodegradation (plume interior vs. background concentrations) are Dissolved oxygen concentrations below background, Nitrate concentrations ...

  20. Inelastic and reactive collisions with polarized excited Na atoms

    SciTech Connect

    Schmidt, H.; Hertel, I.V.; Lee, Y.T.

    1985-07-01

    Polarization effects in inelastic collisions of laser state-prepared Na(3/sup 2/P, M/sub J/) with Na/sup +/ leading to Na(3/sup 2/D) or Na(3/sup 2/S) are discussed for the energy range E/sub cm/ = 5-47.5eV. Studies with linearly polarized light can be explained with a simple ''locking'' model of the Na(P)-orbital. The investigations employing circularly polarized light are a very sensitive test of the models describing the nonadiabatic angular momentum coupling between electronic and nuclear motion. The dynamical effects of the electronic spin on the angular momentum transfer are discussed. Recent crossed-beam experiments on the Na + O/sub 2/ -> NaO = O reaction in the energy range E/sub cm/ = 0/3-0.8eV show a pronounced dependence on the electric electronic symmetry of Na. 17 refs., 11 figs.

  1. Design of Na(+) -Selective Fluorescent Probes: A Systematic Study of the Na(+) -Complex Stability and the Na(+) /K(+) Selectivity in Acetonitrile and Water.

    PubMed

    Schwarze, Thomas; Müller, Holger; Schmidt, Darya; Riemer, Janine; Holdt, Hans-Jürgen

    2017-02-14

    There is a tremendous demand for highly Na(+) -selective fluoroionophores to monitor the top analyte Na(+) in life science. Here, we report a systematic route to develop highly Na(+) /K(+) selective fluorescent probes. Thus, we synthesized a set of fluoroionophores 1, 3, 4, 5, 8 and 9 (see Scheme ) to investigate the Na(+) /K(+) selectivity and Na(+) - complex stability in CH3 CN and H2 O. These Na(+) -probes bear different 15-crown-5 moieties to bind Na(+) stronger than K(+) . In the set of the diethylaminocoumarin-substituted fluoroionophores 1-5, the following trend of fluorescence quenching 1>3>2>4>5 in CH3 CN was observed. Therefore, the flexibility of the aza-15-crown-5 moieties in 1-4 determines the conjugation of the nitrogen lone pair with the aromatic ring. As a consequence, 1 showed in CH3 CN the highest Na(+) -induced fluorescence enhancement (FE) by a factor of 46.5 and a weaker K(+) induced FE of 3.7. The Na(+) -complex stability of 1-4 in CH3 CN is enhanced in the following order of 2>4>3>1, assuming that the O-atom of the methoxy group in the ortho-position, as shown in 2, strengthened the Na(+) -complex formation. Furthermore, we found for the N-(o-methoxyphenyl)aza-15-crown-5 substituted fluoroionophores 2, 8 and 9 in H2 O, an enhanced Na(+) -complex stability in the following order 8>2>9 and an increased Na(+) /K(+) selectivity in the reverse order 9>2>8. Notably, the Na(+) -induced FE of 8 (FEF=10.9), 2 (FEF=5.0) and 9 (FEF=2.0) showed a similar trend associated with a decreased K(+) -induced FE [8 (FEF=2.7)>2 (FEF=1.5)>9 (FEF=1.1)]. Here, the Na(+) -complex stability and Na(+) /K(+) selectivity is also influenced by the fluorophore moiety. Thus, fluorescent probe 8 (Kd =48 mm) allows high-contrast, sensitive, and selective Na(+) measurements over extracellular K(+) levels. A higher Na(+) /K(+) selectivity showed fluorescent probe 9, but also a higher Kd value of 223 mm. Therefore, 9 is a suitable tool to measure Na(+) concentrations up to

  2. Na+-driven bacterial flagellar motors.

    PubMed

    Imae, Y; Atsumi, T

    1989-12-01

    Bacterial flagellar motors are the reversible rotary engine which propels the cell by rotating a helical flagellar filament as a screw propeller. The motors are embedded in the cytoplasmic membrane, and the energy for rotation is supplied by the electrochemical potential of specific ions across the membrane. Thus, the analysis of motor rotation at the molecular level is linked to an understanding of how the living system converts chemical energy into mechanical work. Based on the coupling ions, the motors are divided into two types; one is the H+-driven type found in neutrophiles such as Bacillus subtilis and Escherichia coli and the other is the Na+-driven type found in alkalophilic Bacillus and marine Vibrio. In this review, we summarize the current status of research on the rotation mechanism of the Na+-driven flagellar motors, which introduces several new aspects in the analysis.

  3. The two C-terminal tyrosines stabilize occluded Na/K pump conformations containing Na or K ions.

    PubMed

    Vedovato, Natascia; Gadsby, David C

    2010-07-01

    Interactions of the three transported Na ions with the Na/K pump remain incompletely understood. Na/K pump crystal structures show that the extended C terminus of the Na,K-adenosine triphosphatase (ATPase) alpha subunit directly contacts transmembrane helices. Deletion of the last five residues (KETYY in almost all Na/K pumps) markedly lowered the apparent affinity for Na activation of pump phosphorylation from ATP, a reflection of cytoplasmic Na affinity for forming the occluded E1P(Na3) conformation. ATPase assays further suggested that C-terminal truncations also interfere with low affinity Na interactions, which are attributable to extracellular effects. Because extracellular Na ions traverse part of the membrane's electric field to reach their binding sites in the Na/K pump, their movements generate currents that can be monitored with high resolution. We report here electrical measurements to examine how Na/K pump interactions with extracellular Na ions are influenced by C-terminal truncations. We deleted the last two (YY) or five (KESYY) residues in Xenopus laevis alpha1 Na/K pumps made ouabain resistant by either of two kinds of point mutations and measured their currents as 10-mM ouabain-sensitive currents in Xenopus oocytes after silencing endogenous Xenopus Na/K pumps with 1 microM ouabain. We found the low affinity inhibitory influence of extracellular Na on outward Na/K pump current at negative voltages to be impaired in all of the C-terminally truncated pumps. Correspondingly, voltage jump-induced transient charge movements that reflect pump interactions with extracellular Na ions were strongly shifted to more negative potentials; this signals a several-fold reduction of the apparent affinity for extracellular Na in the truncated pumps. Parallel lowering of Na affinity on both sides of the membrane argues that the C-terminal contacts provide important stabilization of the occluded E1P(Na3) conformation, regardless of the route of Na ion entry into the

  4. The NA62 experiment at CERN

    NASA Astrophysics Data System (ADS)

    Venditti, Stefano

    2016-12-01

    The goal of the NA62 experiment at CERN is to collect O(100) events of the ultrarare K+→ π +ν bar {ν } decay in two years. After a long R&D phase and a successful pilot run in 2014, the first data-taking phase took place in 2015. In this paper the importance of the experiment's physics goal, as well as the experimental solutions adopted in order to attain it, will be reviewed.

  5. The complex lightcurve of 1992 NA

    NASA Technical Reports Server (NTRS)

    Wisniewski, Wieslaw Z.; Harris, A. W.

    1994-01-01

    Amor asteroid 1992 NA was monitored during three nights at a large phase angle of -65 deg. The lightcurves obtained did not reveal a repeatable curve with two maxima and two minima. However, some features suggested a periodicity with three maxima and three minima. A satisfactory composite lightcurve of this form was obtained by means of an 'eyeball' fit and by Fourier analysis. Individual and composite lightcurves are presented. The observed colors are consistent with the C class.

  6. Spontaneous NA+ transients in individual mitochondria of intact astrocytes.

    PubMed

    Azarias, Guillaume; Van de Ville, Dimitri; Unser, Michael; Chatton, Jean-Yves

    2008-02-01

    Mitochondria in intact cells maintain low Na(+) levels despite the large electrochemical gradient favoring cation influx into the matrix. In addition, they display individual spontaneous transient depolarizations. The authors report here that individual mitochondria in living astrocytes exhibit spontaneous increases in their Na(+) concentration (Na(mit)(+) spiking), as measured using the mitochondrial probe CoroNa Red. In a field of view with approximately 30 astrocytes, up to 1,400 transients per minute were typically detected under resting conditions. Na(mit)(+) spiking was also observed in neurons, but was scarce in two nonneural cell types tested. Astrocytic Na(mit)(+) spikes averaged 12.2 +/- 0.8 s in duration and 35.5 +/- 3.2 mM in amplitude and coincided with brief mitochondrial depolarizations; they were impaired by mitochondrial depolarization and ruthenium red pointing to the involvement of a cation uniporter. Na(mit)(+) spiking activity was significantly inhibited by mitochondrial Na(+)/H(+) exchanger inhibition and sensitive to cellular pH and Na(+) concentration. Ca(2+) played a permissive role on Na(mit)(+) spiking activity. Finally, the authors present evidence suggesting that Na(mit)(+) spiking frequency was correlated with cellular ATP levels. This study shows that, under physiological conditions, individual mitochondria in living astrocytes exhibit fast Na(+) exchange across their inner membrane, which reveals a new form of highly dynamic and localized functional regulation.

  7. Glial Na(+) -dependent ion transporters in pathophysiological conditions.

    PubMed

    Boscia, Francesca; Begum, Gulnaz; Pignataro, Giuseppe; Sirabella, Rossana; Cuomo, Ornella; Casamassa, Antonella; Sun, Dandan; Annunziato, Lucio

    2016-10-01

    Sodium dynamics are essential for regulating functional processes in glial cells. Indeed, glial Na(+) signaling influences and regulates important glial activities, and plays a role in neuron-glia interaction under physiological conditions or in response to injury of the central nervous system (CNS). Emerging studies indicate that Na(+) pumps and Na(+) -dependent ion transporters in astrocytes, microglia, and oligodendrocytes regulate Na(+) homeostasis and play a fundamental role in modulating glial activities in neurological diseases. In this review, we first briefly introduced the emerging roles of each glial cell type in the pathophysiology of cerebral ischemia, Alzheimer's disease, epilepsy, Parkinson's disease, Amyotrophic Lateral Sclerosis, and myelin diseases. Then, we discussed the current knowledge on the main roles played by the different glial Na(+) -dependent ion transporters, including Na(+) /K(+) ATPase, Na(+) /Ca(2+) exchangers, Na(+) /H(+) exchangers, Na(+) -K(+) -Cl(-) cotransporters, and Na(+) - HCO3- cotransporter in the pathophysiology of the diverse CNS diseases. We highlighted their contributions in cell survival, synaptic pathology, gliotransmission, pH homeostasis, and their role in glial activation, migration, gliosis, inflammation, and tissue repair processes. Therefore, this review summarizes the foundation work for targeting Na(+) -dependent ion transporters in glia as a novel strategy to control important glial activities associated with Na(+) dynamics in different neurological disorders. GLIA 2016;64:1677-1697.

  8. Route, mechanism, and implications of proton import during Na+/K+ exchange by native Na+/K+-ATPase pumps.

    PubMed

    Vedovato, Natascia; Gadsby, David C

    2014-04-01

    A single Na(+)/K(+)-ATPase pumps three Na(+) outwards and two K(+) inwards by alternately exposing ion-binding sites to opposite sides of the membrane in a conformational sequence coupled to pump autophosphorylation from ATP and auto-dephosphorylation. The larger flow of Na(+) than K(+) generates outward current across the cell membrane. Less well understood is the ability of Na(+)/K(+) pumps to generate an inward current of protons. Originally noted in pumps deprived of external K(+) and Na(+) ions, as inward current at negative membrane potentials that becomes amplified when external pH is lowered, this proton current is generally viewed as an artifact of those unnatural conditions. We demonstrate here that this inward current also flows at physiological K(+) and Na(+) concentrations. We show that protons exploit ready reversibility of conformational changes associated with extracellular Na(+) release from phosphorylated Na(+)/K(+) pumps. Reversal of a subset of these transitions allows an extracellular proton to bind an acidic side chain and to be subsequently released to the cytoplasm. This back-step of phosphorylated Na(+)/K(+) pumps that enables proton import is not required for completion of the 3 Na(+)/2 K(+) transport cycle. However, the back-step occurs readily during Na(+)/K(+) transport when external K(+) ion binding and occlusion are delayed, and it occurs more frequently when lowered extracellular pH raises the probability of protonation of the externally accessible carboxylate side chain. The proton route passes through the Na(+)-selective binding site III and is distinct from the principal pathway traversed by the majority of transported Na(+) and K(+) ions that passes through binding site II. The inferred occurrence of Na(+)/K(+) exchange and H(+) import during the same conformational cycle of a single molecule identifies the Na(+)/K(+) pump as a hybrid transporter. Whether Na(+)/K(+) pump-mediated proton inflow may have any physiological or

  9. pNaKtide inhibits Na/K-ATPase reactive oxygen species amplification and attenuates adipogenesis

    PubMed Central

    Sodhi, Komal; Maxwell, Kyle; Yan, Yanling; Liu, Jiang; Chaudhry, Muhammad A.; Getty, Morghan; Xie, Zijian; Abraham, Nader G.; Shapiro, Joseph I.

    2015-01-01

    Obesity has become a worldwide epidemic and is a major risk factor for metabolic syndrome. Oxidative stress is known to play a role in the generation and maintenance of an obesity phenotype in both isolated adipocytes and intact animals. Because we had identified that the Na/K-ATPase can amplify oxidant signaling, we speculated that a peptide designed to inhibit this pathway, pNaKtide, might ameliorate an obesity phenotype. To test this hypothesis, we first performed studies in isolated murine preadipocytes (3T3L1 cells) and found that pNaKtide attenuated oxidant stress and lipid accumulation in a dose-dependent manner. Complementary experiments in C57Bl6 mice fed a high-fat diet corroborated our in vitro observations. Administration of pNaKtide in these mice reduced body weight gain, restored systemic redox and inflammatory milieu, and, crucially, improved insulin sensitivity. Thus, we propose that inhibition of Na/K-ATPase amplification of oxidative stress may ultimately be a novel way to combat obesity, insulin resistance, and metabolic syndrome. PMID:26601314

  10. Zero-gravity growth of NaF-NaCl eutectics in the NASA Skylab program

    NASA Technical Reports Server (NTRS)

    Yue, A. S.; Allen, F. G.; Yu, J. G.

    1976-01-01

    Continuous and discontinuous NaF fibers, embedded in a NaCl matrix, were produced in space and on earth. The production of continuous fibers in a eutectic mixture is attributed to the absence of convection current in the liquid during solidification in space. Image transmission and optical transmittance measurements of transverse sections of the space-grown and earth-grown ingots were made with a light microscope and a spectrometer. It is shown that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of NaF fibers along the ingot axis. A new concept is advanced to explain the phenomenon of transmittance versus far infrared wavelength of the directionally solidified NaCl-NaF eutectic in terms of the two-dimensional Bragg Scattering and the polarization effect of Rayleigh scattering. This concept can be applied to other eutectic systems as long as the index of refraction of the matrix over a range of wavelengths is known. Experimental data are in agreement with the theoretical prediction.

  11. Plant Defensins NaD1 and NaD2 Induce Different Stress Response Pathways in Fungi

    PubMed Central

    Dracatos, Peter M.; Payne, Jennifer; Di Pietro, Antonio; Anderson, Marilyn A.; Plummer, Kim M.

    2016-01-01

    Nicotiana alata defensins 1 and 2 (NaD1 and NaD2) are plant defensins from the ornamental tobacco that have antifungal activity against a variety of fungal pathogens. Some plant defensins interact with fungal cell wall O-glycosylated proteins. Therefore, we investigated if this was the case for NaD1 and NaD2, by assessing the sensitivity of the three Aspergillus nidulans (An) O-mannosyltransferase (pmt) knockout (KO) mutants (An∆pmtA, An∆pmtB, and An∆pmtC). An∆pmtA was resistant to both defensins, while An∆pmtC was resistant to NaD2 only, suggesting NaD1 and NaD2 are unlikely to have a general interaction with O-linked side chains. Further evidence of this difference in the antifungal mechanism was provided by the dissimilarity of the NaD1 and NaD2 sensitivities of the Fusarium oxysporum f. sp. lycopersici (Fol) signalling knockout mutants from the cell wall integrity (CWI) and high osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathways. HOG pathway mutants were sensitive to both NaD1 and NaD2, while CWI pathway mutants only displayed sensitivity to NaD2. PMID:27598152

  12. Effect of Na+ on surface fractal dimension of compacted bentonite

    NASA Astrophysics Data System (ADS)

    Xiang, G. S.; Xu, Y. F.; Jiang, H.

    2015-05-01

    Compacted Tsukinuno bentonite was immersed into NaCl solutions of different concentrations in oedometers, and the surface fractal dimension of bentonite-saline association was measured by nitrogen adsorption isotherms. The application of the Frenkel-Halsey-Hill equation and the Neimark thermodynamic method to nitrogen adsorption isotherms indicated that the surface roughness was greater for the bentonite-saline association. The surface fractal dimension of bentonite increased in the NaCl solution with low Na+ concentration, but decreased at high Na+ concentration. This process was accompanied by the same tendency in specific surface area and microporosity with the presence of Na+ coating in the clay particles.

  13. Na+-K+ pump regulation and skeletal muscle contractility.

    PubMed

    Clausen, Torben

    2003-10-01

    In skeletal muscle, excitation may cause loss of K+, increased extracellular K+ ([K+]o), intracellular Na+ ([Na+]i), and depolarization. Since these events interfere with excitability, the processes of excitation can be self-limiting. During work, therefore, the impending loss of excitability has to be counterbalanced by prompt restoration of Na+-K+ gradients. Since this is the major function of the Na+-K+ pumps, it is crucial that their activity and capacity are adequate. This is achieved in two ways: 1) by acute activation of the Na+-K+ pumps and 2) by long-term regulation of Na+-K+ pump content or capacity. 1) Depending on frequency of stimulation, excitation may activate up to all of the Na+-K+ pumps available within 10 s, causing up to 22-fold increase in Na+ efflux. Activation of the Na+-K+ pumps by hormones is slower and less pronounced. When muscles are inhibited by high [K+]o or low [Na+]o, acute hormone- or excitation-induced activation of the Na+-K+ pumps can restore excitability and contractile force in 10-20 min. Conversely, inhibition of the Na+-K+ pumps by ouabain leads to progressive loss of contractility and endurance. 2) Na+-K+ pump content is upregulated by training, thyroid hormones, insulin, glucocorticoids, and K+ overload. Downregulation is seen during immobilization, K+ deficiency, hypoxia, heart failure, hypothyroidism, starvation, diabetes, alcoholism, myotonic dystrophy, and McArdle disease. Reduced Na+-K+ pump content leads to loss of contractility and endurance, possibly contributing to the fatigue associated with several of these conditions. Increasing excitation-induced Na+ influx by augmenting the open-time or the content of Na+ channels reduces contractile endurance. Excitability and contractility depend on the ratio between passive Na+-K+ leaks and Na+-K+ pump activity, the passive leaks often playing a dominant role. The Na+-K+ pump is a central target for regulation of Na+-K+ distribution and excitability, essential for second

  14. Na+ channel function, regulation, structure, trafficking and sequestration

    PubMed Central

    Chen-Izu, Ye; Shaw, Robin M; Pitt, Geoffrey S; Yarov-Yarovoy, Vladimir; Sack, Jon T; Abriel, Hugues; Aldrich, Richard W; Belardinelli, Luiz; Cannell, Mark B; Catterall, William A; Chazin, Walter J; Chiamvimonvat, Nipavan; Deschenes, Isabelle; Grandi, Eleonora; Hund, Thomas J; Izu, Leighton T; Maier, Lars S; Maltsev, Victor A; Marionneau, Celine; Mohler, Peter J; Rajamani, Sridharan; Rasmusson, Randall L; Sobie, Eric A; Clancy, Colleen E; Bers, Donald M

    2015-01-01

    This paper is the second of a series of three reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation–contraction coupling and arrhythmias: Na+ channel and Na+ transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on Na+ channel function and regulation, Na+ channel structure and function, and Na+ channel trafficking, sequestration and complexing. PMID:25772290

  15. Jahn–Teller Assisted Na Diffusion for High Performance Na Ion Batteries

    SciTech Connect

    Li, Xin; Wang, Yan; Wu, Di; Liu, Lei; Bo, Shou-Hang; Ceder, Gerbrand

    2016-08-30

    Na energy storage technology is strategically attractive for large scale applications such as grid energy storage. Here, we show in this paper that there is a clear relation between the Jahn$-$Teller activity of a transition metal ion at the end of charge and the mobility of Na in a cathode material. This is particularly important as mobility at the end of charge limits the capacity of current materials. Consequently, by using this classical piece of physics in the battery world, it is possible to create higher capacity Na-cathode materials. Even more exciting is that the ideal element to impart this effect on cathodes is Fe, which is the least expensive of the transition metal oxides and can therefore enable low cost cathode materials.

  16. Synthesis of Na-A and/or Na-X zeolite/porous carbon composites from carbonized rice husk

    SciTech Connect

    Katsuki, Hiroaki; Komarneni, Sridhar

    2009-07-15

    Na-A and/or Na-X zeolite/porous carbon composites were prepared under hydrothermal conditions by NaOH dissolution of silica first from carbonized rice husk followed by addition of NaAlO{sub 2} and in situ crystallization of zeolites i.e., using a two-step process. When a one-step process was used, both Na-A and Na-X zeolites crystallized on the surface of carbon. Na-A or Na-X zeolite crystals were prepared on the porous carbonized rice husk at 90 deg. C for 2-6 h by changing the SiO{sub 2}/Al{sub 2}O{sub 3}, H{sub 2}O/Na{sub 2}O and Na{sub 2}O/SiO{sub 2} molar ratios of precursors in the two-step process. The surface area and NH{sub 4}{sup +}-cation exchange capacity (CEC) of Na-A zeolite/porous carbon were found to be 171 m{sup 2}/g and 506 meq/100 g, respectively, while those of Na-X zeolite/porous carbon composites were 676 m{sup 2}/g and 317 meq/100 g, respectively. Na-A and Na-X zeolites are well-known microporous and hydrophilic materials while carbonized rice husk was found to be mesoporous (pores of {approx}3.9 nm) and hydrophobic. These hybrid microporous-mesoporous and hydrophilic-hydrophobic composites are expected to be useful for decontamination of metal cations as well as organic contaminants simultaneously. - Graphical Abstract: Novel Na-X zeolite/porous carbon composite.

  17. Specific oxidation pattern of soluble starch with TEMPO-NaBr-NaClO system.

    PubMed

    Hao, Jie; Lu, Jiaojiao; Xu, Naiyu; Linhardt, Robert J; Zhang, Zhenqing

    2016-08-01

    Oxidized starch, one of the most important starch derivatives, has many different properties and applications. Currently, there are two ways to produce oxidized starch, through specific and nonspecific oxidation. Specific oxidation using the stable nitroxyl radical, 2,2,6,6-tetramethyl preparidinloxy (TEMPO), with NaBr and NaClO can produce oxidized starches with different properties under good quality control. In the current study, we examine the products of specifically oxidized starch. As the amount of oxidant and the temperature, two critical factors impacting the oxidation of starch were thoroughly investigated. Analysis of the molecular weight (MW), degree of oxidization (DO) and the detailed structures of corresponding products was accomplished using gel permeation chromatography with multi-angle laser light scattering (GPC-MALLS), infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and quadrapole time-of-flight mass spectrometry (Q/TOF-MS). According to the analytical results, the oxidation patterns of starch treated with specific oxidant TEMPO-NaBr-NaClO were established. When high amounts of oxidant was applied, more glucose residues within starch were oxidized to glucuronic acids (higher DO) and substantial degradation to starch oligosaccharides was observed. By selecting a reaction temperature of 25°C a high DO could be obtained for a given amount of oxidant. The reducing end sugar residue within oxidized starch was itself oxidized and ring opened in all TEMPO-NaBr-NaClO reactions. Furthermore, extra oxidant generated additional novel structures in the reducing end residues of some products, particularly in low temperature reactions.

  18. Neutron spectroscopy of water dynamics in NaX and NaA zeolites

    NASA Astrophysics Data System (ADS)

    Kamitakahara, William A.; Wada, Noboru

    2008-04-01

    We have investigated the dynamics of water molecules in zeolites NaA and NaX by high-resolution quasielastic neutron scattering methods. Between 260 and 310 K, the local translational diffusive motion of water in the zeolites is one to two orders of magnitude slower than in bulk water. The Q dependence of the scattering shows effects of confinement and the presence of both relatively mobile and immobile molecules. The speed of the diffusive motion depends strongly on hydration level. Comparison with other hydrated siliceous materials indicates that the host charge per water molecule is a major factor in determining the time scale of diffusion.

  19. Design and implementation of the NaI(Tl)/CsI(Na) detectors output signal generator

    NASA Astrophysics Data System (ADS)

    Zhou, Xu; Liu, Cong-Zhan; Zhao, Jian-Ling; Zhang, Fei; Zhang, Yi-Fei; Li, Zheng-Wei; Zhang, Shuo; Li, Xu-Fang; Lu, Xue-Feng; Xu, Zhen-Ling; Lu, Fang-Jun

    2014-02-01

    We designed and implemented a signal generator that can simulate the output of the NaI(Tl)/CsI(Na) detectors' pre-amplifier onboard the Hard X-ray Modulation Telescope (HXMT). Using the development of the FPGA (Field Programmable Gate Array) with VHDL language and adding a random constituent, we have finally produced the double exponential random pulse signal generator. The statistical distribution of the signal amplitude is programmable. The occurrence time intervals of the adjacent signals contain negative exponential distribution statistically.

  20. FT-IR and XRD analysis of natural Na-bentonite and Cu(II)-loaded Na-bentonite.

    PubMed

    Zhirong, Liu; Azhar Uddin, Md; Zhanxue, Sun

    2011-09-01

    Na-bentonite has been studied extensively because of its strong adsorption capacity and complexation ability. In this work, surface area, total pore volume, mean pore diameter, TG, DTA, FT-IR and XRD were carried out in order to reveal the characteristics of natural Na-bentonite. XRD and FT-IR of natural Na-bentonite (China) and Cu-loaded Na-bentonite as a function of Na-bentonite dosage and temperature using batch technique were characterized in detail, respectively.

  1. FT-IR and XRD analysis of natural Na-bentonite and Cu(II)-loaded Na-bentonite

    NASA Astrophysics Data System (ADS)

    Zhirong, Liu; Azhar Uddin, Md.; Zhanxue, Sun

    2011-09-01

    Na-bentonite has been studied extensively because of its strong adsorption capacity and complexation ability. In this work, surface area, total pore volume, mean pore diameter, TG, DTA, FT-IR and XRD were carried out in order to reveal the characteristics of natural Na-bentonite. XRD and FT-IR of natural Na-bentonite (China) and Cu-loaded Na-bentonite as a function of Na-bentonite dosage and temperature using batch technique were characterized in detail, respectively.

  2. The NA62 experiment at CERN

    NASA Astrophysics Data System (ADS)

    Piccini, Mauro

    2016-11-01

    The rare decays K → πvv¯ are excellent processes to make tests of new physics at the highest scale complementary to LHC thanks to their theoretically cleanness. The NA62 experiment at CERN SPS aims to collect of the order of 100 events in two years of data taking for the decay K+ → π+vv¯, keeping the background at the level of 10%. Part of the experimental apparatus has been commissioned during a technical run in 2012. The diverse and innovative experimental techniques will be explained and some preliminary results obtained during the 2014 pilot run will be reviewed.

  3. Status of the NA62 Experiment

    NASA Astrophysics Data System (ADS)

    Palladino, Vito

    2016-04-01

    The rare decays {{{K}}^ + } to {π ^ + }{{ν bar ν }} are excellent processes to make tests of new physics at the highest scale complementary to LHC thanks to their theoretically cleaness. The NA62 experiment at CERN SPS aims to collect of the order of 100 events in two years of data taking, keeping the background at the level of 10%. Part of the experimental apparatus has been commissioned during a technical run in 2012. The physics prospects and the status of the experiment will be reviewed after the commissioning run of 2014 and the data taking in 2015.

  4. The NA62 Gigatracker pixel detector system

    NASA Astrophysics Data System (ADS)

    Mazza, G.; Ceccucci, A.; Cortina, E.; Cotta Ramusino, A.; Dellacasa, G.; Fiorini, M.; Garbolino, S.; Jarron, P.; Kaplon, J.; Kluge, A.; Marchetto, F.; Martin, E.; Martoiu, S.; Noy, M.; Petrucci, F.; Riedler, P.; Rivetti, A.; Tiuraniemi, S.

    2010-05-01

    The silicon tracker for the NA62 experiment has to provide both a time resolution of 150 ps rms and a space resolution of about 100 μm rms. These challenging specifications require the development of a new readout electronics in order to address the problem of measuring the tracks arrival time with such a high channel density. Moreover, the high particle density (up to 1.5 MHz/mm2 in the center and 0.8-1 GHz in total) requires a high speed measurement and data transmission in order to keep the dead time below 1%.

  5. Novel regulation of cell [Na(+)] in macula densa cells: apical Na(+) recycling by H-K-ATPase.

    PubMed

    Peti-Peterdi, János; Bebok, Zsuzsa; Lapointe, Jean-Yves; Bell, P Darwin

    2002-02-01

    Na-K-ATPase is the nearly ubiquitous enzyme that maintains low-Na(+), high-K(+) concentrations in cells by actively extruding Na(+) in exchange for K(+). The prevailing paradigm in polarized absorbing epithelial cells, including renal nephron segments and intestine, has been that Na-K-ATPase is restricted to the basolateral membrane domain, where it plays a prominent role in Na(+) absorption. We have found, however, that macula densa (MD) cells lack functionally and immunologically detectable amounts of Na-K-ATPase protein. In fact, these cells appear to regulate their cytosolic [Na(+)] via another member of the P-type ATPase family, the colonic form of H-K-ATPase, which is located at the apical membrane in these cells. We now report that this constitutively expressed apical MD colonic H-K-ATPase can function as a Na(H)-K-ATPase and regulate cytosolic [Na(+)] in a novel manner. This apical Na(+)-recycling mechanism may be important as part of the sensor function of MD cells and represents a new paradigm in cell [Na(+)] regulation.

  6. Penning and associative ionization in crossed-beam Na/Na collisions assisted by strong resonant laser fields

    SciTech Connect

    Weiner, J.; Polak-Dingels, P.

    1981-01-01

    We observe the production of Na/sub 2//sup +/ and Na/sup +/ arising from single collisions between crossed beams of sodium atoms when a laser field is tuned near the Na(3p /sup 2/P/sub 3/2/) and Na(3p /sup 2/P/sub 1/2/) transitions. Measurements of ion intensity vs laser intensity show that at moderately high power true laser-induced processes dominate over purely collisional effects. Relative intensity of mass-selected ions produced at either member of the Na resonance doublet shows conclusively that Na/sup +/ does not arise simply from photodissociation of Na/sub 2//sup +/ but must result from a direct, laser-induced collisional ionization.

  7. Vanadate sensitivity of Na+, K+-ATPase from Schistosoma mansoni and its modulation by Na+, K+ and Mg2+.

    PubMed

    Noel, F; Pardon, R S

    1989-01-01

    Vanadate inhibitory effects on Na+, K+-ATPases from carcass of Schistosoma mansoni and from lamb kidney outer medulla were compared in the presence of various concentrations of Na+, K+ and Mg2+. Depending on the ionic conditions, the schistosomal Na+, K+-ATPase was 2.4- to 175-fold less sensitive to vanadate than the lamb kidney enzyme. In 100 mM Na+, 3 mM K+ and 3 mM Mg2+, schistosomal Na+, K+-ATPase was surprisingly resistant to vanadate (I50 = 944 microM). The difference in vanadate sensitivity between schistosomal and lamb Na+, K+-ATPases may be due to a species difference in the efficacy of Na+, K+ and Mg2+ in promoting conformational changes between E1 and E2 forms of the enzyme.

  8. NaSrMn2F7, NaCaFe2F7, and NaSrFe2F7: novel single crystal pyrochlore antiferromagnets

    NASA Astrophysics Data System (ADS)

    Sanders, M. B.; Krizan, J. W.; Plumb, K. W.; McQueen, T. M.; Cava, R. J.

    2017-02-01

    The crystal structures and magnetic properties of three previously unreported A2B2F7 pyrochlore materials, NaSrMn2F7, NaCaFe2F7, and NaSrFe2F7 are presented. In these compounds, either S  =  2Fe2+ or S  =  5/2Mn2+ is on the B site, while nonmagnetic Na and Ca (Na and Sr) are disordered on the A site. The materials, which were grown as crystals via the floating zone method, display high effective magnetic moments and large Curie-Weiss thetas. Despite these characteristics, no ordering transition is detected. However, freezing of the magnetic spins, characterized by peaks in the susceptibility or specific heat, is observed at very low temperatures. The empirical frustration index, f  =  -θ CW/T f, for the materials are 36 (NaSrMn2F7), 27 (NaSrFe2F7), and 19 (NaCaFe2F7). AC susceptibility, DC susceptibility, and heat capacity measurements are used to characterize the observed spin glass behavior. The results suggest that the compounds are frustrated pyrochlore antiferromagnets with weak bond disorder. The magnetic phenomena that these fluoride pyrochlores exhibit, in addition to their availability as relatively large single crystals, make them promising candidates for the study of geometric magnetic frustration.

  9. The NA62 GigaTracker

    NASA Astrophysics Data System (ADS)

    Aglieri Rinella, G.; Feito, D. Alvarez; Arcidiacono, R.; Biino, C.; Bonacini, S.; Ceccucci, A.; Chiozzi, S.; Gil, E. Cortina; Ramusino, A. Cotta; Degrange, J.; Fiorini, M.; Gamberini, E.; Gianoli, A.; Kaplon, J.; Kluge, A.; Mapelli, A.; Marchetto, F.; Minucci, E.; Morel, M.; Noël, J.; Noy, M.; Perktold, L.; Perrin-Terrin, M.; Petagna, P.; Petrucci, F.; Poltorak, K.; Romagnoli, G.; Ruggiero, G.; Velghe, B.; Wahl, H.

    2017-02-01

    The GigaTracker is a hybrid silicon pixel detector built for the NA62 experiment aiming at measuring the branching fraction of the ultra-rare kaon decay K+ →π+ ν ν bar at the CERN SPS. The detector has to track particles in a beam with a flux reaching 1.3 MHz/mm2 and provide single-hit timing with 200 ps RMS resolution for a total material budget of less than 0.5% X0 per station. The tracker comprises three 60.8 mm×27 mm stations installed in vacuum (∼10-6 mbar) and cooled with liquid C6F14 circulating through micro-channels etched inside a few hundred micron thick silicon plates. Each station is composed of a 200 μm thick silicon sensor read out by 2×5 custom 100 μm thick ASICs, called TDCPix. Each chip contains 40×45 asynchronous pixels, 300 μm×300 μm each and is instrumented with 100 ps bin time-to-digital converters. In order to cope with the high rate, the TDCPix is equipped with four 3.2 Gb/s serialisers sending out the data. We will describe the detector and the results from the 2014 and 2015 NA62 runs.

  10. Elevated intracellular Na(+) concentrations in developing spinal neurons.

    PubMed

    Lindsly, Casie; Gonzalez-Islas, Carlos; Wenner, Peter

    2017-03-01

    Over 25 years ago it was first reported that intracellular chloride levels (Cl(-)in ) were higher in developing neurons than in maturity. This finding has had significant implications for understanding the excitability of developing networks and recognizing the underlying causes of hyperexcitability associated with disease and neural injury. While there is some evidence that intracellular sodium levels (Na(+)in ) change during the development of non-neural cells, it has largely been assumed that Na(+)in is the same in developing and mature neurons. Here, using the sodium indicator SBFI, we test this idea and find that Na(+)in is significantly higher in embryonic spinal motoneurons and interneurons than in maturity. We find that Na(+)in reaches ~ 60 mM in mid-embryonic development and is then reduced to ~ 30 mM in late embryonic development. By retrogradely labeling motoneurons with SBFI we can reliably follow Na(+)in levels in vitro for hours. Bursts of spiking activity, and blocking voltage-gated sodium channels did not influence observed motoneuron sodium levels. On the other hand, Na(+)in was reduced by blocking the Na(+) -K(+) -2Cl(-) cotransporter NKCC1, and was highly sensitive to changes in external Na(+) and a blocker of the Na(+) /K(+) ATPase. Our findings suggest that the Na(+) gradient is weaker in embryonic neuronal development and strengthens in maturity in a manner similar to that of Cl(-) .

  11. Minimizing Load Effects on NA4 Gear Vibration Diagnostic Parameter

    NASA Technical Reports Server (NTRS)

    Dempsey, Paula J.; Zakrajsek, James J.

    2001-01-01

    NA4 is a vibration diagnostic parameter, developed by researchers at NASA Glenn Research Center, for health monitoring of gears in helicopter transmissions. The NA4 reacts to the onset of gear pitting damage and continues to react to the damage as it spreads. This research also indicates NA4 reacts similarly to load variations. The sensitivity of NA4 to load changes will substantially affect its performance on a helicopter gearbox that experiences continuously changing load throughout its flight regimes. The parameter NA4 has been used to monitor gear fatigue tests at constant load. At constant load, NA4 effectively detects the onset of pitting damage and tracks damage severity. Previous research also shows that NA4 reacts to changes in load applied to the gears in the same way it reacts to the onset of pitting damage. The method used to calculate NA4 was modified to minimize these load effects. The modified NA4 parameter was applied to four sets of experimental data. Results indicate the modified NA4 is no longer sensitive to load changes, but remains sensitive to pitting damage.

  12. Rydberg States of Na-doped Helium Nanodroplets

    NASA Astrophysics Data System (ADS)

    Drabbels, Marcel

    2008-03-01

    The dynamics of excited states of Na atoms deposited on the surface of helium nanodroplets has been investigated with velocity map ion imaging, photoelectron spectroscopy and time-of-flight mass-spectroscopy. For the first time, the excitation spectra of Na-doped helium nanodroplets corresponding to Rydberg states of Na atoms have been measured from the lowest excited 3p state up to the ionization threshold. All lines in the excitation spectra are shifted and broadened with respect to the corresponding atomic lines. In addition to bare Na* atoms also Na*HeN (N = 1-6) exciplexes are detected upon excitation. Photoelectron spectroscopy reveals the desorption of Na* not only in the initially excited states but also in lower lying states, indicating that relaxation plays an important role. The recorded velocity distributions show interesting characteristics: for the lowest states the mean kinetic energy of Na* increases linearly with excitation energy. The velocity distributions of Na*HeN exciplexes do not manifest such remarkable properties. The observations can be largely explained by assuming that the interaction of Na* with the helium nanodroplet can be described by the sum of Na*-He pair potentials.

  13. Direct interaction of Na-azide with the KATP channel.

    PubMed

    Trapp, S; Ashcroft, F M

    2000-11-01

    1. The effects of the metabolic inhibitor sodium azide were tested on excised macropatches from Xenopus oocytes expressing cloned ATP-sensitive potassium (KATP) channels of the Kir6.2/SUR1 type. 2. In inside-out patches from oocytes expressing Kir6.2 delta C36 (a truncated form of Kir6.2 that expresses in the absence of SUR), intracellular Na-azide inhibited macroscopic currents with an IC50 of 11 mM. The inhibitory effect of Na-azide was mimicked by the same concentration of NaCl, but not by sucrose. 3. Na-azide and NaCl blocked Kir6.2/SUR1 currents with IC50 of 36 mM and 19 mM, respectively. Inhibition was abolished in the absence of intracellular Mg2+. In contrast, Kir6.2 delta C36 currents were inhibited by Na-azide both in the presence or absence of intracellular Mg2+. 4. Kir6.2/SUR1 currents were less sensitive to 3 mM Na-azide in the presence of MgATP. This apparent reduction in sensitivity is caused by a small activatory effect of Na-azide conferred by SUR. 5. We conclude that, in addition to its well-established inhibitory effect on cellular metabolism, which leads to activation of KATP channels in intact cells, intracellular Na-azide has direct effects on the KATP channel. Inhibition is intrinsic to Kir6.2, is mediated by Na+, and is modulated by SUR. There is also a small, ATP-dependent, stimulatory effect of Na-azide mediated by the SUR subunit. The direct effects of 3 mM Na-azide on KATP channels are negligible in comparison to the metabolic activation produced by the same Na-azide concentration.

  14. Theoretical calculation of low-lying states of NaAr and NaXe

    NASA Technical Reports Server (NTRS)

    Laskowski, B. C.; Langhoff, S. R.; Stallcop, J. R.

    1981-01-01

    Potential curves as well as dipole moments and linking transition moments are calculated for the ground X 2 Sigma + and low lying excited A 2 Pi, B 2 Sigma +, C 2 Sigma +, (4) 2 Sigma +, (2) 2 Pi and (1) 2 Delta states of NaAr and NaXe. Calculations are performed using a self-consistent field plus configuration-interaction procedure with the core electrons replaced by an ab initio effective core potential. The potential curves obtained are found to be considerably less repulsive than the semiempirical curves of Pascale and Vandeplanque (1974) and to agree well with existing experimental data, although the binding energies of those states having potential minima due to van der Waals interactions are underestimated. Emission bands are also calculated for the X 2 Sigma + - C 2 Sigma + excimer transitions of NaAr and NaXe using the calculated transition moments and potential curves, and shown to agree well with experiment on the short-wavelength side of the maximum.

  15. 24Mg(p, α)21Na reaction study for spectroscopy of 21Na

    DOE PAGES

    Cha, S. M.; Chae, K. Y.; Kim, A.; ...

    2015-11-03

    The Mg-24(p, alpha)Na-21 reaction was measured at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory in order to better constrain the spins and parities of the energy levels in Na-21 for the astrophysically important F-17(alpha, p)Ne-20 reaction rate calculation. 31-MeV proton beams from the 25-MV tandem accelerator and enriched Mg-24 solid targets were used. When recoiling He-4 particles from the Mg-24(p, alpha)Na-21 reaction we used a highly segmented silicon detector array to detect them; it measured the yields of He-4 particles over a range of angles simultaneously. A observed a new level at 6661 ± 5 keVmore » in the present work. The extracted angular distributions for the first four levels of Na-21 and the results from distorted wave Born approximation (DWBA) calculations were compared to verify and extract the angular momentum transfer.« less

  16. Regulation of persistent Na current by interactions between beta subunits of voltage-gated Na channels.

    PubMed

    Aman, Teresa K; Grieco-Calub, Tina M; Chen, Chunling; Rusconi, Raffaella; Slat, Emily A; Isom, Lori L; Raman, Indira M

    2009-02-18

    The beta subunits of voltage-gated Na channels (Scnxb) regulate the gating of pore-forming alpha subunits, as well as their trafficking and localization. In heterologous expression systems, beta1, beta2, and beta3 subunits influence inactivation and persistent current in different ways. To test how the beta4 protein regulates Na channel gating, we transfected beta4 into HEK (human embryonic kidney) cells stably expressing Na(V)1.1. Unlike a free peptide with a sequence from the beta4 cytoplasmic domain, the full-length beta4 protein did not block open channels. Instead, beta4 expression favored open states by shifting activation curves negative, decreasing the slope of the inactivation curve, and increasing the percentage of noninactivating current. Consequently, persistent current tripled in amplitude. Expression of beta1 or chimeric subunits including the beta1 extracellular domain, however, favored inactivation. Coexpressing Na(V)1.1 and beta4 with beta1 produced tiny persistent currents, indicating that beta1 overcomes the effects of beta4 in heterotrimeric channels. In contrast, beta1(C121W), which contains an extracellular epilepsy-associated mutation, did not counteract the destabilization of inactivation by beta4 and also required unusually large depolarizations for channel opening. In cultured hippocampal neurons transfected with beta4, persistent current was slightly but significantly increased. Moreover, in beta4-expressing neurons from Scn1b and Scn1b/Scn2b null mice, entry into inactivated states was slowed. These data suggest that beta1 and beta4 have antagonistic roles, the former favoring inactivation, and the latter favoring activation. Because increased Na channel availability may facilitate action potential firing, these results suggest a mechanism for seizure susceptibility of both mice and humans with disrupted beta1 subunits.

  17. [Na] and [K] dependence of the Na/K pump current-voltage relationship in guinea pig ventricular myocytes

    PubMed Central

    1989-01-01

    Na/K pump current was determined between -140 and +60 mV as steady- state, strophanthidin-sensitive, whole-cell current in guinea pig ventricular myocytes, voltage-clamped and internally dialyzed via wide- tipped pipettes. Solutions were designed to minimize all other components of membrane current. A device for exchanging the solution inside the pipette permitted investigation of Na/K pump current-voltage (I-V) relationships at several levels of pipette [Na] [( Na]pip) in a single cell; the effects of changes in external [Na] [( Na]o) or external [K] [( K]o) were also studied. At 50 mM [Na]pip, 5.4 mM [K]o, and approximately 150 mM [Na]o, Na/K pump current was steeply voltage dependent at negative potentials but was approximately constant at positive potentials. Under those conditions, reduction of [Na]o enhanced pump current at negative potentials but had little effect at positive potentials: at zero [Na]o, pump current was only weakly voltage dependent. At 5.4 mM [K]o and approximately 150 mM [Na]o, reduction of [Na]pip from 50 mM scaled down the sigmoid pump I-V relationship and shifted it slightly to the right (toward more positive potentials). Pump current at 0 mV was activated by [Na]pip according to the Hill equation with best-fit K0.5 approximately equal to 11 mM and Hill coefficient nH approximately equal to 1.4. At zero [Na]o, reduction of [Na]pip seemed to simply scale down the relatively flat pump I-V relationship: Hill fit parameters for pump activation by [Na]pip at 0 mV were K0.5 approximately equal to 10 mM, nH approximately equal to 1.4. At 50 mM [Na]pip and high [Na]o, reduction of [K]o from 5.4 mM scaled down the sigmoid I-V relationship and shifted it slightly to the right: at 0 mV, K0.5 approximately equal to 1.5 mM and nH approximately equal to 1.0. At zero [Na]o, lowering [K]o simply scaled down the flat pump I-V relationships yielding, at 0 mV, K0.5 approximately equal to 0.2 mM, nH approximately equal to 1.1. The voltage

  18. Coordinated regulation of cardiac Na(+)/Ca (2+) exchanger and Na (+)-K (+)-ATPase by phospholemman (FXYD1).

    PubMed

    Cheung, Joseph Y; Zhang, Xue-Qian; Song, Jianliang; Gao, Erhe; Chan, Tung O; Rabinowitz, Joseph E; Koch, Walter J; Feldman, Arthur M; Wang, JuFang

    2013-01-01

    Phospholemman (PLM) is the founding member of the FXYD family of regulators of ion transport. PLM is a 72-amino acid protein consisting of the signature PFXYD motif in the extracellular N terminus, a single transmembrane (TM) domain, and a C-terminal cytoplasmic tail containing three phosphorylation sites. In the heart, PLM co-localizes and co-immunoprecipitates with Na(+)-K(+)-ATPase, Na(+)/Ca(2+) exchanger, and L-type Ca(2+) channel. The TM domain of PLM interacts with TM9 of the α-subunit of Na(+)-K(+)-ATPase, while its cytoplasmic tail interacts with two small regions (spanning residues 248-252 and 300-304) of the proximal intracellular loop of Na(+)/Ca(2+) exchanger. Under stress, catecholamine stimulation phosphorylates PLM at serine(68), resulting in relief of inhibition of Na(+)-K(+)-ATPase by decreasing K(m) for Na(+) and increasing V(max), and simultaneous inhibition of Na(+)/Ca(2+) exchanger. Enhanced Na(+)-K(+)-ATPase activity lowers intracellular Na(+), thereby minimizing Ca(2+) overload and risks of arrhythmias. Inhibition of Na(+)/Ca(2+) exchanger reduces Ca(2+) efflux, thereby preserving contractility. Thus, the coordinated actions of PLM during stress serve to minimize arrhythmogenesis and maintain inotropy. In acute cardiac ischemia and chronic heart failure, either expression or phosphorylation of PLM or both are altered. PLM regulates important ion transporters in the heart and offers a tempting target for development of drugs to treat heart failure.

  19. Pyrophosphate-Fueled Na+ and H+ Transport in Prokaryotes

    PubMed Central

    Malinen, Anssi M.; Luoto, Heidi H.

    2013-01-01

    SUMMARY In its early history, life appeared to depend on pyrophosphate rather than ATP as the source of energy. Ancient membrane pyrophosphatases that couple pyrophosphate hydrolysis to active H+ transport across biological membranes (H+-pyrophosphatases) have long been known in prokaryotes, plants, and protists. Recent studies have identified two evolutionarily related and widespread prokaryotic relics that can pump Na+ (Na+-pyrophosphatase) or both Na+ and H+ (Na+,H+-pyrophosphatase). Both these transporters require Na+ for pyrophosphate hydrolysis and are further activated by K+. The determination of the three-dimensional structures of H+- and Na+-pyrophosphatases has been another recent breakthrough in the studies of these cation pumps. Structural and functional studies have highlighted the major determinants of the cation specificities of membrane pyrophosphatases and their potential use in constructing transgenic stress-resistant organisms. PMID:23699258

  20. The paranodal cytoskeleton clusters Na(+) channels at nodes of Ranvier.

    PubMed

    Amor, Veronique; Zhang, Chuansheng; Vainshtein, Anna; Zhang, Ao; Zollinger, Daniel R; Eshed-Eisenbach, Yael; Brophy, Peter J; Rasband, Matthew N; Peles, Elior

    2017-01-30

    A high density of Na(+) channels at nodes of Ranvier is necessary for rapid and efficient action potential propagation in myelinated axons. Na+ channel clustering is thought to depend on two axonal cell adhesion molecules that mediate interactions between the axon and myelinating glia at the nodal gap (i.e., NF186) and the paranodal junction (i.e., Caspr). Here we show that while Na(+) channels cluster at nodes in the absence of NF186, they fail to do so in double conditional knockout mice lacking both NF186 and the paranodal cell adhesion molecule Caspr, demonstrating that a paranodal junction-dependent mechanism can cluster Na(+) channels at nodes. Furthermore, we show that paranode-dependent clustering of nodal Na(+) channels requires axonal βII spectrin which is concentrated at paranodes. Our results reveal that the paranodal junction-dependent mechanism of Na(+)channel clustering is mediated by the spectrin-based paranodal axonal cytoskeleton.

  1. Neutron diffraction studies of the Na-ion battery electrode materials NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3

    NASA Astrophysics Data System (ADS)

    Yahia, H. Ben; Essehli, R.; Avdeev, M.; Park, J.-B.; Sun, Y.-K.; Al-Maadeed, M. A.; Belharouak, I.

    2016-06-01

    The new compounds NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 were synthesized by sol-gel method and their crystal structures were determined by using neutron powder diffraction data. These compounds were characterized by galvanometric cycling and cyclic voltammetry. NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 crystallize with a stuffed α-CrPO4-type structure. The structure consists of a 3D-framework made of octahedra and tetrahedra that are sharing corners and/or edges generating channels along [100] and [010], in which the sodium atoms are located. Of significance, in the structures of NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 a statistical disorder Ni2+/Cr3+ was observed on both the 8g and 4a atomic positions, whereas in NaCoCr2(PO4)3 the statistical disorder Co2+/Cr3+ was only observed on the 8g atomic position. When tested as negative electrode materials, NaCoCr2(PO4)3, NaNiCr2(PO4)3, and Na2Ni2Cr(PO4)3 delivered specific capacities of 352, 385, and 368 mA h g-1, respectively, which attests to the electrochemical activity of sodium in these compounds.

  2. Simulation of Na D emission near Europa during eclipse

    USGS Publications Warehouse

    Cassidy, T.A.; Johnson, R.E.; Geissler, P.E.; Leblanc, F.

    2008-01-01

    The Cassini imaging science subsystem observed Europa in eclipse during Cassini's Jupiter flyby. The disk-resolved observations revealed a spatially nonuniform emission in the wavelength range of 200-1050 nm (clear filters). By building on observations and simulations of Europa's Na atmosphere and torus we find that electron-excited Na in Europa's tenuous atmosphere can account for the observed emission if the Na is ejected preferentially from Europa's dark terrain. Copyright 2008 by the American Geophysical Union.

  3. Magnesium correction to the NaKCa chemical geothermometer

    USGS Publications Warehouse

    Fournier, R.O.; Potter, R.W.

    1979-01-01

    Equations and graphs have been devised to correct for the adverse effects of magnesium upon the Na-K-Ca chemical geothermometer. Either the equations or graphs can be used to determine appropriate temperature corrections for given waters with calculated NaKCa temperatures > 70??C and R 50 are probably derived from relatively cool aquifers with temperatures approximately equal to the measured spring temperature, irrespective of much higher calculated Na-K-Ca temperatures. ?? 1979.

  4. Kinetic properties and Na+ dependence of rheogenic Na(+)-HCO3- co-transport in frog retinal pigment epithelium.

    PubMed Central

    la Cour, M

    1991-01-01

    1. Na(+)-HCO3- co-transport across the retinal membrane of the frog retinal pigment epithelium was studied by means of double-barrelled pH-selective microelectrodes. Transient changes in the intracellular pH were monitored in response to abrupt changes in the Na+ concentration on the retinal side of the epithelium. 2. The experiments were performed as follows. The Na(+)-HCO3- co-transport was inhibited by perfusing the retinal side of the epithelium with a Na(+)-free solution. The co-transport was then stimulated by changing the perfusate from the Na(+)-free solution to a solution which contained from 5 to 110 mM-Na+. The resulting inward Na(+)-HCO3- co-transport produced an intracellular alkalinization, the initial rate of which was used to calculate the initial rate of Na(+)-HCO3- co-transport, JHCO3-. 3. The Na+ dependence of the Na(+)-HCO3- co-transport was studied at two different values of extracellular pH (7.40 and 7.10), at constant extracellular HCO3- concentration (27.5 mM) and at two different extracellular HCO3- concentrations (27.5 mM and 55 mM) at constant extracellular pH (7.40). In these experiments, the calculated values of JHCO3- followed single Michaelis-Menten kinetics with respect to the extracellular Na+ concentration. 4. The data are consistent with a model in which the co-transporter has a single binding site for the Na+ ion with an apparent affinity constant (apparent Km) of 37 mM. The apparent affinity constant for Na+ was independent of the extracellular concentration of CO3(2-) in the range of 16-65 microM, and of the extracellular HCO3- concentration in the range 27.5-55 mM. 5. The NaCO3- ion-pair hypothesis, in which sodium binds to the co-transporter and is translocated across the cell membrane as the NaCO3- ion pair, was analysed. For stoichiometries 1:2 and 1:3 of the Na(+)-HCO3- co-transport, the NaCO3- ion-pair hypothesis was found incompatible with the data. 6. The intracellular buffer capacity as measured by the CO2 method was

  5. The NA49 large acceptance hadron detector

    NASA Astrophysics Data System (ADS)

    Afanasiev, S.; Alber, T.; Appelshäuser, H.; Bächler, J.; Barna, D.; Barnby, L. S.; Bartke, J.; Barton, R. A.; Betev, L.; Bialkowska, H.; Bieser, F.; Billmeier, A.; Blyth, C. O.; Bock, R.; Bormann, C.; Bracinik, J.; Brady, F. P.; Brockmann, R.; Brun, R.; Buncic, P.; Caines, H. L.; Cebra, D.; Cooper, G. E.; Cramer, J. G.; Csato, P.; Cyprian, M.; Dunn, J.; Eckardt, V.; Eckhardt, F.; Empl, T.; Eschke, J.; Ferguson, M. I.; Fessler, H.; Fischer, H. G.; Flierl, D.; Fodor, Z.; Frankenfeld, U.; Foka, P.; Freund, P.; Friese, V.; Ftacnik, J.; Fuchs, M.; Gabler, F.; Gal, J.; Ganz, R.; Gaździcki, M.; Gładysz, E.; Grebieszkow, J.; Günther, J.; Harris, J. W.; Hegyi, S.; Henkel, T.; Hill, L. A.; Hlinka, V.; Huang, I.; Hümmler, H.; Igo, G.; Irmscher, D.; Ivanov, M.; Janik, R.; Jacobs, P.; Jones, P. G.; Kadija, K.; Kolesnikov, V. I.; Kowalski, M.; Lasiuk, B.; Lévai, P.; Liebicher, K.; Lynen, U.; Malakhov, A. I.; Margetis, S.; Markert, C.; Marks, C.; Mayes, B.; Melkumov, G. L.; Mock, A.; Molnár, J.; Nelson, J. M.; Oldenburg, M.; Odyniec, G.; Palla, G.; Panagiotou, A. D.; Pestov, Y.; Petridis, A.; Pikna, M.; Pimpl, W.; Pinsky, L.; Piper, A.; Porter, R. J.; Poskanzer, A. M.; Poziombka, S.; Prindle, D. J.; Pühlhofer, F.; Rauch, W.; Reid, J. G.; Renfordt, R.; Retyk, W.; Ritter, H. G.; Röhrich, D.; Roland, C.; Roland, G.; Rudolph, H.; Rybicki, A.; Sammer, T.; Sandoval, A.; Sann, H.; Schäfer, E.; Schmidt, R.; Schmischke, D.; Schmitz, N.; Schönfelder, S.; Semenov, A. Yu.; Seyboth, J.; Seyboth, P.; Seyerlein, J.; Sikler, F.; Sitar, B.; Skrzypczak, E.; Squier, G. T. A.; Stelzer, H.; Stock, R.; Strmen, P.; Ströbele, H.; Struck, C.; Susa, T.; Szarka, I.; Szentpetery, I.; Szymański, P.; Sziklai, J.; Toy, M.; Trainor, T. A.; Trentalange, S.; Ullrich, T.; Vassiliou, M.; Veres, G.; Vesztergombi, G.; Vranic, D.; Wang, F. Q.; Weerasundara, D. D.; Wenig, S.; Whitten, C.; Wieman, H.; Wienold, T.; Wood, L.; Yates, T. A.; Zimanyi, J.; Zhu, X.-Z.; Zybert, R.

    1999-07-01

    The NA49 detector is a wide acceptance spectrometer for the study of hadron production in p+p, p+A, and A+A collisions at the CERN SPS. The main components are 4 large-volume TPCs for tracking and particle identification via d E/d x. TOF scintillator arrays complement particle identification. Calorimeters for transverse energy determination and triggering, a detector for centrality selection in p+A collisions, and beam definition detectors complete the set-up. A description of all detector components is given with emphasis on new technical realizations. Performance and operational experience are discussed in particular with respect to the high track density environment of central Pb+Pb collisions.

  6. Pion and kaon freezeout in NA44

    SciTech Connect

    NA44 Collaboration

    1994-12-01

    The NA44 spectrometer is optimized for the study of single and two-particle particle spectra near mid-rapidity for transverse momenta below {approx} 1 GeV/c. A large fraction of all pairs in the spectrometer`s acceptance are at low relative momenta, resulting in small statistical uncertainties on the extracted size parameters. In addition, the spectrometer`s clean particle identification allows the authors to measure correlation functions for pions, kaons, and protons. This contribution will concentrate on the source size parameters determined from pion and kaon correlation functions. These size parameters will be compared to calculations from the RQMD event generator and also interpreted in the context of a hydrodynamic model. Finally, the measured single particle spectra will be examined from the viewpoint of hydrodynamics.

  7. Na-Zn liquid metal battery

    NASA Astrophysics Data System (ADS)

    Xu, Junli; Kjos, Ole Sigmund; Osen, Karen Sende; Martinez, Ana Maria; Kongstein, Ole Edvard; Haarberg, Geir Martin

    2016-11-01

    A new kind of membrane free liquid metal battery was developed. The battery employs liquid sodium and zinc as electrodes both in liquid state, and NaCl-CaCl2 molten salts as electrolyte. The discharge flat voltage is in the range of about 1.4 V-1.8 V, and the cycle efficiency achieved is about 90% at low discharge current densities (below 40 mA cm-2). Moreover, this battery can also be charged and discharged at high current density with good performance. The discharge flat voltage is above 1.1 V when it is discharged at 100 mA cm-2, while it is about 0.8 V with 100% cycle efficiency when it is discharged at 200 mA cm-2. Compared to other reported liquid metal battery, this battery has lower cost, which suggests broad application prospect in energy storage systems for power grid.

  8. Study of OSL in NaF: Ca,Cu

    NASA Astrophysics Data System (ADS)

    More, Y. K.; Wankhede, S. P.; Moharil, S. V.

    2013-06-01

    Sodium Fluoride containing Cu+ ions was prepared by R.A.P. followed by melt-quenching technique. Results on photo, thermo and optically stimulated luminescence in NaF:Ca,Cu are reported. OSL sensitivity of NaF:Ca,Cu is approximately 2 times than that of standard phosphor LMP. The rate of OSL depletion for 90% decay for NaF:Ca,Cu is 0.3 times as that of OSL phosphor LMP. NaF:Ca,Cu thus deserves much more attention than it has received up till now.

  9. New solid conductors of Na/+/ and K/+/ ions

    NASA Technical Reports Server (NTRS)

    Singer, J.; Fielder, W. L.; Kautz, H. E.; Fordyce, J. S.

    1976-01-01

    About 40 structure types for solid conductors of Na(+) and K(+) ions are surveyed. Five compounds in three structure types are discovered to be good solid conductors of alkali metal ions, capable of ion transport with conductivities in the vicinity of 0.00001/ohm-cm at 25 C. These compounds are a bcc form of NaSbO3, an orthorhombic layer structure of the composition 2M2O.3Nb2O5 with M equal to Na or K, and the Na pyrochlores NaTa2O5F and NaTaWO6. Ion exchange is required to produce each of these Na compounds. Only the 2K2O.3Nb2O5 can so far be synthesized directly from the oxides and thus is the only one which can be sintered readily. The niobate is about as good a conductor of K(+) ion as is K-beta alumina. The NaSbO3 compares well with Na beta at 280 C. A number of phase diagrams are developed.

  10. The Physiological Relevance of Na+-Coupled K+-Transport.

    PubMed Central

    Maathuis, FJM.; Verlin, D.; Smith, F. A.; Sanders, D.; Fernandez, J. A.; Walker, N. A.

    1996-01-01

    Plant roots utilize at least two distinct pathways with high and low affinities to accumulate K+. The system for high-affinity K+ uptake, which takes place against the electrochemical K+ gradient, requires direct energization. Energization of K+ uptake via Na+ coupling has been observed in algae and was recently proposed as a mechanism for K+ uptake in wheat (Triticum aestivum L.). To investigate whether Na+ coupling has general physiological relevance in energizing K+ transport, we screened a number of species, including Arabidopsis thaliana L. Heynh. ecotype Columbia, wheat, and barley (Hordeum vulgare L.), for the presence of Na+-coupled K+ uptake. Rb+-flux analysis and electrophysiological K+-transport assays were performed in the presence and absence of Na+ and provided evidence for a coupling between K+ and Na+ transport in several aquatic species. However, all investigated terrestrial species were able to sustain growth and K+ uptake in the absence of Na+. Furthermore, the addition of Na+ was either without effect or inhibited K+ absorption. The latter characteristic was independent of growth conditions with respect to Na+ status and pH. Our results suggest that in terrestrial species Na+-coupled K+ transport has no or limited physiological relevance, whereas in certain aquatic angiosperms and algae this type of secondary transport energization plays a significant role. PMID:12226467

  11. Influenza virus neuraminidase (NA): a target for antivirals and vaccines.

    PubMed

    Jagadesh, Anitha; Salam, Abdul Ajees Abdul; Mudgal, Piya Paul; Arunkumar, Govindakarnavar

    2016-08-01

    Influenza, the most common infectious disease, poses a great threat to human health because of its highly contagious nature and fast transmissibility, often leading to high morbidity and mortality. Effective vaccination strategies may aid in the prevention and control of recurring epidemics and pandemics associated with this infectious disease. However, antigenic shifts and drifts are major concerns with influenza virus, requiring effective global monitoring and updating of vaccines. Current vaccines are standardized primarily based on the amount of hemagglutinin, a major surface antigen, which chiefly constitutes these preparations along with the varying amounts of neuraminidase (NA). Anti-influenza drugs targeting the active site of NA have been in use for more than a decade now. However, NA has not been approved as an effective antigenic component of the influenza vaccine because of standardization issues. Although some studies have suggested that NA antibodies are able to reduce the severity of the disease and induce a long-term and cross-protective immunity, a few major scientific issues need to be addressed prior to launching NA-based vaccines. Interestingly, an increasing number of studies have shown NA to be a promising target for future influenza vaccines. This review is an attempt to consolidate studies that reflect the strength of NA as a suitable vaccine target. The studies discussed in this article highlight NA as a potential influenza vaccine candidate and support taking the process of develo