Science.gov

Sample records for obra na amazonia

  1. Amazonia and Global Change

    NASA Astrophysics Data System (ADS)

    Keller, Michael; Bustamante, Mercedes; Gash, John; Silva Dias, Pedro

    Amazonia and Global Change synthesizes results of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) for scientists and students of Earth system science and global environmental change. LBA, led by Brazil, asks how Amazonia currently functions in the global climate and biogeochemical systems and how the functioning of Amazonia will respond to the combined pressures of climate and land use change, such as • Wet season and dry season aerosol concentrations and their effects on diffuse radiation and photosynthesis • Increasing greenhouse gas concentration, deforestation, widespread biomass burning and changes in the Amazonian water cycle • Drought effects and simulated drought through rainfall exclusion experiments • The net flux of carbon between Amazonia and the atmosphere • Floodplains as an important regulator of the basin carbon balance including serving as a major source of methane to the troposphere • The impact of the likely increased profitability of cattle ranching. The book will serve a broad community of scientists and policy makers interested in global change and environmental issues with high-quality scientific syntheses accessible to nonspecialists in a wide community of social scientists, ecologists, atmospheric chemists, climatologists, and hydrologists.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

    2015-08-01

    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

  7. 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

  8. Predicting anthropogenic soils across the Amazonia

    NASA Astrophysics Data System (ADS)

    Mcmichael, C.; Palace, M. W.; Bush, M. B.; Braswell, B. H.; Hagen, S. C.; Silman, M.; Neves, E.; Czarnecki, C.

    2012-12-01

    Hidden under the forest canopy in lowland Amazonia are nutrient-enriched soils, called terra pretas (or Amazonian black earths), which were formed by prehistoric indigenous populations. These anthrosols are in stark contrast to typical nutrient-poor Amazonian soils, and have retained increased nutrient levels for hundreds of years. Because of their long-term nutrient retaining ability, terra pretas may be crucial for developing sustainable agricultural practices in Amazonia, especially given the deforestation necessary for traditional slash-and-burn systems. However, the frequency and distribution of terra preta soils across the landscape remains debatable, and archaeologists have estimated that terra pretas cover anywhere from 0.1% to 10% of the lowland Amazonian forests. The highest concentration of terra preta soils has been found along the central and eastern portions of the Amazon River and its major tributaries, but whether this is a true pattern or simply reflects sampling bias remains unknown. A possible explanation is that specific environmental or biotic conditions were preferred for human settlement and terra preta formation. Here, we use environmental parameters to predict the probabilities of terra preta soils across lowland Amazonian forests. We compiled a database of 2708 sites across Amazonia, including locations that contain terra pretas (n = 917), and those that are known to be terra preta-free (n = 1791). More than 20 environmental variables, including precipitation, elevation, slope, soil fertility, and distance to river were converted into 90-m resolution raster images across Amazonia and used to model the probability of terra preta occurrence. The relationship between the predictor variables and the occurrence of terra preta was examined using three modeling techniques: logistic regression, auto-logistic regression, and maximum entropy estimations. All three techniques provided similar predictions for terra preta distributions and the amount

  9. 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.

  10. 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.

  11. 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. PMID:25380507

  12. Within-canopy sesquiterpene ozonolysis in Amazonia

    NASA Astrophysics Data System (ADS)

    Jardine, K.; YañEz Serrano, A.; Arneth, A.; Abrell, L.; Jardine, A.; van Haren, J.; Artaxo, P.; Rizzo, L. V.; Ishida, F. Y.; Karl, T.; Kesselmeier, J.; Saleska, S.; Huxman, T.

    2011-10-01

    Through rapid reactions with ozone, which can initiate the formation of secondary organic aerosols, the emission of sesquiterpenes from vegetation in Amazonia may have significant impacts on tropospheric chemistry and climate. Little is known, however, about sesquiterpene emissions, transport, and chemistry within plant canopies owing to analytical difficulties stemming from very low ambient concentrations, high reactivities, and sampling losses. Here, we present ambient sesquiterpene concentration measurements obtained during the 2010 dry season within and above a primary tropical forest canopy in Amazonia. We show that by peaking at night instead of during the day, and near the ground instead of within the canopy, sesquiterpene concentrations followed a pattern different from that of monoterpenes, suggesting that unlike monoterpene emissions, which are mainly light dependent, sesquiterpene emissions are mainly temperature dependent. In addition, we observed that sesquiterpene concentrations were inversely related with ozone (with respect to time of day and vertical concentration), suggesting that ambient concentrations are highly sensitive to ozone. These conclusions are supported by experiments in a tropical rain forest mesocosm, where little atmospheric oxidation occurs and sesquiterpene and monoterpene concentrations followed similar diurnal patterns. We estimate that the daytime dry season ozone flux of -0.6 to -1.5 nmol m-2 s-1 due to in-canopy sesquiterpene reactivity could account for 7%-28% of the net ozone flux. Our study provides experimental evidence that a large fraction of total plant sesquiterpene emissions (46%-61% by mass) undergo within-canopy ozonolysis, which may benefit plants by reducing ozone uptake and its associated oxidative damage.

  13. 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. PMID:24403329

  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. Reconstructing Rodinia: the view from Amazonia

    NASA Astrophysics Data System (ADS)

    Tohver, E.; van der Pluijm, B.; Van der Voo, R.; Scandolara, J.; Rizzotto, G.

    2001-05-01

    Many Rodinia reconstructions propose that the North American Grenville orogeny at c.1.1 Ga was due to collision between Laurentia and the western Amazon craton, the position of which is presently unrestricted by paleomagnetic data. New paleomagnetic data was collected from the flat-lying basalts and gabbros of the Nova Floresta Formation (K-Ar whole rock, 982 +/-10 Ma, 1038 +/-14 Ma) of Rondonia, western Brazil to constrain the paleogeography of the proposed Laurentia-Amazonia link. Measurement of the anisotropy of magnetic susceptibility (AMS) on the gabbroic samples reveals a flat-lying foliation with a radiating pattern of lineations, demonstrating that the gabbros are part of a large, undeformed sill. Thermal and alternating field (AF) demagnetization of the basalt samples reveals a single component that is oriented WNW and steeply upward. For the gabbro samples, AF demagnetization is more successful than thermal demagnetization at resolving individual components. A characteristic remanence isolated in fields commonly above 40 mT is identical to the single component recorded in the basalts, suggesting that this magnetization was acquired at the same time. A paleomagnetic N-pole calculated from the Nova Floresta Formation (n = 16 sites, Plat. = 26.1N, PLon. = 163.4E, A95 = 5.9) can be matched to the Laurentia APWP for the 1150-750 Ma interval and permits geographic proximity of the two cratons during Grenvillian times. However, the orientation of the Aguapee-Sunsas belt based on this pole suggests a N-S oriented belt, in contrast with the E-W orientation of the Grenville belt on the Laurentian margin. It is proposed that the Amazon craton was rotated 90 degrees counterclockwise from the orientation required by the Laurentia-Amazonia connection. This N-S orientation of the Sunsas-Aguapei belt suggests that the western margin of the Amazon craton was juxtaposed with the Namaqua belt of the western Kalahari craton. This configuration is supported by a common

  16. Soils of amazonia with particular reference to the rainfor sites

    NASA Astrophysics Data System (ADS)

    Quesada, C. A.; Lloyd, J.; Anderson, L. O.; Fyllas, N. M.; Schwarz, M.; Czimczik, C. I.

    2009-04-01

    The tropical forests of Amazonia occur on a wide variety of different soil types reflecting a rich diversity of geologic and geomorphologic conditions. We here review the existing literature about the main soil groups of Amazonia, describing their genesis, geographical patterns and principal chemical, physical and morphologic characteristics. Original data is also presented with profiles of exchangeable cations, carbon and particle size fraction illustrated for the principal soil types, also emphasizing the high diversity existing within the main soil groups when possible. Maps of geographic distribution of soils occurring under forest vegetation are also introduced, and to contextualize soils into an evolutionary framework, a scheme of soil development is proposed having as its basis a chemical weathering index. We identify a continuum of soil evolution in Amazonia with soil properties varying predictably along this pedogenetic gradient.

  17. 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

  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. 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. PMID:27191598

  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. PMID:22523580

  1. 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

  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. PMID:26814648

  3. 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

  4. 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

  5. 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.

  6. 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

  7. High Resolution Simulation in the Eastern Amazonia

    NASA Astrophysics Data System (ADS)

    Cohen, J.; Sa, L.; Nogueira, D.; Gandu, A.

    2006-05-01

    A particularly important research domain is referred to the forest-atmosphere interaction, since the flow in the region immediately above the vegetation is complex and has characteristics still not well known. One of these characteristics is the existence, in some situations, of relative maxima in the wind velocity vertical profiles, the "low level jets" (LLJ), in regions less than 1 km distant from the surface. They may contribute to intensify the mixture in the surface and in the region where they occur. It is possible that the presence of such phenomenon introduce additional difficulties in the parameterization of the forest-atmosphere exchange processes. Therefore, it is entirely reasonable the study of LLJs in order to determine the conditions of their occurrence and to investigate the consequences of their existence in the characteristics of the Nocturnal Boundary Layer (NBL) structure near the surface. This work presents the results of numerical simulations with the model BRAMS (Brazilian developments on the Regional Atmospheric Modeling System) for the study of LLJs in the Eastern Amazonia. The numerical simulations presented contained 3 nested grids with a horizontal spacing of 45, 15 and 5 km. The vertical resolution was variable with an initial spacing of 100m in the lowest layer of the model, increasing upward by the factor of 1.2 until the vertical spacing reaches 1000m. In the model, 12 soil layers were defined until the depth of 4m. The vegetation coverage distribution used was produced by CPTEC (Sestini et al., 2002). The model's initialization was variable, each 6 hours, with the analysis of CPTEC's global model, the radiosondes and surface data. The simulation used the models of surface and vegetation, radiation, cloud microphysics, deep convective parameterization of Grell and shallow convection parameterization. The temporal vertical distribution of the wind speed obtained from the radiosondes launched at each 3 hours in Caxiuana and those

  8. Soils of Amazonia with particular reference to the RAINFOR sites

    NASA Astrophysics Data System (ADS)

    Quesada, C. A.; Lloyd, J.; Anderson, L. O.; Fyllas, N. M.; Schwarz, M.; Czimczik, C. I.

    2011-06-01

    The tropical forests of the Amazon Basin occur on a wide variety of different soil types reflecting a rich diversity of geologic origins and geomorphic processes. We here review the existing literature about the main soil groups of Amazonia, describing their genesis, geographical patterns and principal chemical, physical and morphologic characteristics. Original data is also presented, with profiles of exchangeable cations, carbon and particle size fraction illustrated for the principal soil types; also emphasizing the high diversity existing within the main soil groups when possible. Maps of geographic distribution of soils occurring under forest vegetation are also introduced, and to contextualize soils into an evolutionary framework, a scheme of soil development is presented having as its basis a chemical weathering index. We identify a continuum of soil evolution in Amazonia with soil properties varying predictably along this pedogenetic gradient.

  9. 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.

  10. Could Ecosystem Change over Amazonia Influence Climate over North America?

    NASA Astrophysics Data System (ADS)

    Fu, R.; Arias Gomez, P. A.; Wang, H.

    2014-12-01

    Earth system model experiments suggest that ecosystem changes in the Northern Hemisphere could influence climate over the Southern Hemisphere, or vice versa. In reality, whether an ecosystem change could have a detectable influence on climate variability in remote regions is not clear. Direct validation of such an influence based on available climate records is not feasible largely because we cannot isolate the influences of ecosystems from more dominant sources of climate variability from ocean and atmosphere. However, our observational analysis suggests that the variability of wet season onset over the Amazonia, which is significantly influenced by evapotranspiration of the rainforest, could influence the demise of the North American monsoon. Such a remote influence appears to be carried out by the influence of the Amazonia rainfall on the cross-equatorial flow and latitudinal propagation of the atmospheric waves, which in turn, influence wind and moisture transport over the North American monsoon region. These results suggest that perhaps the future reduction of evapotranspiration due to CO2 fertilization and large-scale land use over the Amazonia will not only delay the wet season onset over this region, but also impact the demise of the North American monsoon.

  11. Probabilistic rainfall anomalies over Amazonia associated with ENSO events

    NASA Astrophysics Data System (ADS)

    sansigolo, clovis

    2014-05-01

    ENSO extreme events are associated with climatic extremes over many regions of the globe. Over Amazonia, El Niño and La Niña events are respectively associated with below and above normal rainfall anomalies in the wet season (Sept - May). Correlations and regressions are the methods commonly used for composite analyses. They assume linear interactions between SST anomalies and the expected climatic anomalies, no inter-events differences, symmetries between El Niño and La Niña climatic impacts, and normality of rainfall anomalies, assumptions not found in some regions. A simple and robust alternative method uses contingency tables to assess the influence of an independent variable (El Niño/La Niña) on the probability of a predefined climatic event (e.g. rainfall anomaly tercil). Monthly rainfall data in 30 stations distributed over the region (1950/51 - 2000/01) were used in this work. Seasonal rainfall anomalies were sorted and allocated in tercils corresponding to below, near and above normal categories. Standardized seasonal averages of Niño 3.4 indices were used to assess the phase impact of the 11 strongest El Niño and La Niña events observed in the period. The significance of the number of times that simultaneous and 1 to 3 months lagged rainfall anomalies during ENSO extreme events were in each considered tercil was calculated using 3x2 contingency tables. The significance of the results was assessed using a hypothesis test based on the hypergeometric distribution. Simultaneous and 1 to 3 months lagged below normal rainfall in the northern and central part of the region were significant associated with El Niño in the austral summer (mature phase). In their typical development (SON) phase they were significant associated with below normal rainfall in central Amazonia, simultaneously and 3 months lagged. La Niñas in their development phases (SON) were significantly associated with above normal rainfall in the beginning of the rainy season in eastern

  12. 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.

  13. 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.

  14. Further evidence for significant smoke transport from Africa to Amazonia

    NASA Astrophysics Data System (ADS)

    Baars, H.; Ansmann, A.; Althausen, D.; Engelmann, R.; Artaxo, P.; Pauliquevis, T.; Souza, R.

    2011-10-01

    Polarization-Raman-lidar observations of vertical aerosol profiles were performed 60 km north of Manaus, Brazil, in the Amazon rain forest during Amazonia's wet season from January to May 2008. Very clean background conditions with a mean AOD (532 nm) of 0.03 ± 0.02 were frequently found. However, in about one third of all lidar measurements advection of smoke and dust aerosol from Africa were observed. The contribution of African smoke and Saharan dust particles to the total backscatter and extinction coefficient was determined by means of the measured particle depolarization ratio. A decreasing contribution of smoke particles to the total particle extinction coefficient from values around 60%-80% in January and February 2008, to values of 0%-50% in May 2008 was observed. Smoke-related extinction coefficients and optical depths up to 80 Mm-1 and 0.15 at 532 nm, respectively, were recorded.

  15. 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. PMID:24779443

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Regional climate change over eastern Amazonia caused by pasture and soybean cropland expansion

    NASA Astrophysics Data System (ADS)

    Sampaio, Gilvan; Nobre, Carlos; Heil Costa, Marcos; Satyamurty, Prakki; Silveira Soares-Filho, Britaldo; Cardoso, Manoel

    2007-09-01

    Field observations and numerical studies revealed that large scale deforestation in Amazonia could alter the regional climate significantly, projecting a warmer and somewhat drier post-deforestation climate. In this study we employed the CPTEC-INPE AGCM to assess the effects of Amazonian deforestation on the regional climate, using simulated land cover maps from a business-as-usual scenario of future deforestation in which the rainforest was gradually replaced by degraded pasture or by soybean cropland. The results for eastern Amazonia, where changes in land cover are expected to be larger, show increase in near-surface air temperature, and decrease in evapotranspiration and precipitation, which occurs mainly during the dry season. The relationship between precipitation and deforestation shows an accelerating decrease of rainfall for increasing deforestation for both classes of land use conversions. Continued expansion of cropland in Amazonia is possible and may have important consequences for the sustainability of the region's remaining natural vegetation.

  2. [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. PMID:19503956

  3. Chemical composition of rainwater in western Amazonia — Brazil

    NASA Astrophysics Data System (ADS)

    Honório, B. A. D.; Horbe, A. M. C.; Seyler, P.

    2010-11-01

    An extensive sample study in western Amazonia, Brazil was performed over the course of one year to i) establish the natural influence of the forest, ii) determine the contribution of the vegetation and fossil fuel burning and iii) detect the geographical and temporal influences on the rainwater composition. Six sampling stations were chosen on two 1000 km-long orthogonal axes. Parintins, Itapiranga, Manaus, Tabatinga were the stations from East to West, and Boa Vista, Manaus, and Apui were the stations from North to South. The results indicate a complex control of the chemical composition of the rainwater and a rather high heterogeneity among the stations. This heterogeneity can be explained by the influence of biogenic, terrestrial dust, agriculture activities and biomass-burning aerosols, and the urban development of Manaus City with its rapid increase in the use of fossil fuel. The isotopic composition of the rainwater indicates that from the north and west sides to the south and east sides, a slight geographical and temporal gradient exists, and more δ180 enriched rainwater tends to be present in the west (Tabatinga) and in the North (Boa Vista). During the dry season a more negative δ180 rainwater was observed in Manaus and Boa Vista stations, as compared to others stations. This observation indicates the more intense evaporative contribution of rainwater as a consequence of a rapid deforestation (savannization) process in the Manaus region.

  4. 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.

  5. 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

  6. Evaporation from young secondary vegetation in eastern Amazonia

    NASA Astrophysics Data System (ADS)

    Hölscher, D.; de A. Sá, T. D.; Bastos, T. X.; Denich, M.; Fölster, H.

    1997-06-01

    The fallow vegetation of the slash and burn agriculture in eastern Amazonia is dominated by shrubs and trees. This study of evaporation from such secondary vegetation started when the above-ground parts of the vegetation were approximately 2.5 years old. The results are based mainly on a data set containing 231 days of micrometeorological observations in the period from April 1992 to April 1993. Evaporation values obtained with the Penman open water formula ranged from 1.1 to 7.2 mm d-1, with an overall mean of 4.6 mm d-1. Actual evaporation, calculated with the Bowen ratio approach, varied from 1.2 to 5.9 mm d-1, with an overall mean of 3.9 mm d-1. Due to the high net radiation and vapour pressure deficit, and the evenly distributed moderate rainfall, the actual evaporation was constantly high during the transition between the rainy and dry seasons. In a relatively dry period, water limitations were indicated by a decrease in the actual evaporation compared with the Penman open water evaporation. Day-to-day variability was pronounced in the rainy season. An overall average of 79% of the net radiation was converted to latent heat flux. The annual evaporation was calculated by an interpolation of missing data with the continuously observed net radiation. The total actual evaporation was estimated to be 1364 mm a-1, against rainfall of 1819 mm a-1; the remaining 455 mm were allocated to drainage. When actual evaporation exceeded rainfall during the dry season, there had to be access to water storage down to depths of more than 3 m. We conclude that the young secondary vegetation can re-evaporate an important part of the rainfall input in spite of the marked seasonal distribution of rainfall. Possible regional climatic changes due to deforestation may be less severe in areas where woody secondary vegetation plays an important role in land cover.

  7. Tracking anthropogenic influence on isoprene chemistry over Amazonia

    NASA Astrophysics Data System (ADS)

    Liu, Y.; McKinney, K. A.; Watson, T. B.; Springston, S. R.; Seco, R.; Park, J. H.; Kim, S.; Shilling, J. E.; Guenther, A. B.; Dorris, M. R.; Thayer, M.; Keutsch, F. N.; Yee, L.; Isaacman, G. A.; Goldstein, A. H.; Wurm, F.; Ferreira De Brito, J.; Artaxo, P.; Silva Dias, M. A. F.; Longo, K.; Souza, R. A. F. D.; Manzi, A. O.; Martin, S. T.

    2014-12-01

    Primarily emitted by vegetation, isoprene is the dominant nonmethane hydrocarbon in the atmosphere. Photooxidation of isoprene has a large influence on the oxidation capacity of the atmosphere and the production of secondary organic aerosol (SOA). As a part of the GoAmazon2014 Experiment, isoprene and some of its oxidation products were measured using a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) at a research site 60 km west of the city of Manaus, Brazil. The fetch of the research site oscillated between the extremes of a pristine atmosphere and the interactions of heavy pollution from Manaus with the natural environment, which allowed for an assessment of the modifications of natural isoprene chemistry by anthropogenic pollution over Amazonia. Photooxidation of isoprene leads to chemically different oxidation products depending on the fate of isoprene peroxy radicals (ISOPOO), but different oxidation products can produce the same ions in PTR-MS analysis due to similarity in their chemical structures. A cold trap was deployed in front of the PTR-TOF-MS for separation and differential classification of some of these isoprene oxidation products. For example, isoprene-derived hydroperoxides (C5H10O3) and methyl vinyl ketone/methacrolein (C4H6O), which are the major oxidation products of the HO2 and NO pathways of ISOPOO reaction, respectively, and both detected as C4H7O+ ion by PTR-MS, were separately measured. Using the measurements of these and other oxidation products of isoprene by PTR-TOF-MS and other complementary measurements, the isoprene chemistry (particularly the fate of ISOPOO) under pristine and polluted scenarios are compared and the implication for SOA formation is discussed.

  8. 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.

  9. 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.

  10. 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.

  11. 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…

  12. 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...

  13. 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.

  14. 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. PMID:12430660

  15. Brazilian Amazonia Deforestation Detection Using Spatio-Temporal Scan Statistics

    NASA Astrophysics Data System (ADS)

    Vieira, C. A. O.; Santos, N. T.; Carneiro, A. P. S.; Balieiro, A. A. S.

    2012-07-01

    The spatio-temporal models, developed for analyses of diseases, can also be used for others fields of study, including concerns about forest and deforestation. The aim of this paper is to quantitatively check priority areas in order to combat deforestation on the Amazon forest, using the space-time scan statistic. The study area location is at the south of the Amazonas State and cover around 297.183 kilometre squares, including the municipality of Boca do Acre, Labrea, Canutama, Humaita, Manicore, Novo Aripuana e Apui County on the north region of Brazil. This area has showed a significant change for land cover, which has increased the number of deforestation's alerts. Therefore this situation becomes a concern and gets more investigation, trying to stop factors that increase the number of cases in the area. The methodology includes the location and year that deforestation's alert occurred. These deforestation's alerts are mapped by the DETER (Detection System of Deforestation in Real Time in Amazonia), which is carry out by the Brazilian Space Agency (INPE). The software SatScanTM v7.0 was used in order to define space-time permutation scan statistic for detection of deforestation cases. The outcome of this experiment shows an efficient model to detect space-time clusters of deforestation's alerts. The model was efficient to detect the location, the size, the order and characteristics about activities at the end of the experiments. Two clusters were considered actives and kept actives up to the end of the study. These clusters are located in Canutama and Lábrea County. This quantitative spatial modelling of deforestation warnings allowed: firstly, identifying actives clustering of deforestation, in which the environment government official are able to concentrate their actions; secondly, identifying historic clustering of deforestation, in which the environment government official are able to monitoring in order to avoid them to became actives again; and finally

  16. 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

  17. 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

  18. Remote sensing of forest dynamics and land use in Amazonia

    NASA Astrophysics Data System (ADS)

    Toomey, Michael Paul

    The rich, vast Amazonian ecosystem is directly and indirectly threatened by human activities; remote sensing serves as an essential tool for monitoring, understanding and mitigating these threats. A multi-faceted body of work is described here, addressing three major issues that employ and advance remote sensing techniques for the study of Amazonia and other tropical rainforest regions. In Chapter 2, canopy reflectance modeling and satellite observations were used to quantify the effect of epiphylls on remote sensing of humid forests. Modeling simulations demonstrated sensitivity of canopy-level near infrared and green reflectance to epiphylls on leaves. Time series of Moderate Resolution Imaging Spectrometer (MODIS) data corroborated the modeling results, suggesting a degree of coupling between epiphyll cover and vegetation indices which must be accounted for when using optical remote sensing in humid forests. In Chapter 4, 11 years (2000--2010) of MODIS land surface temperature (LST) data covering the entire Amazon basin were used to ascertain the role of heat stress during droughts in 2005 and 2010. Preliminary accuracy assessments showed that LST data provided reasonably accurate estimates of daytime air temperatures (RMSE = 1.45°C; Chapter 3). There were moderate to strong correlations between LST-based air temperature estimates and tower measurements (mean r = 0.64), illustrating a sensitivity to temporal variability. During both droughts, MODIS LST data detected anomalously high daytime and nighttime canopy temperatures throughout drought-affected regions. Multivariate linear models of LST and precipitation anomalies explained 65.1% of the variability in forest biomass losses, as determined from a wide network of forest inventory plots. These results suggest that models should incorporate both heat and moisture to predict drought effects on tropical forests. In Chapter 5, I performed high spatial and temporal resolution modeling of carbon stocks and fluxes

  19. 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

  20. 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

  1. Mid-Late Pleistocene OSL chronology in western Amazonia and implications for the transcontinental Amazon pathway

    NASA Astrophysics Data System (ADS)

    Rossetti, Dilce F.; Cohen, Marcelo C. L.; Tatumi, Sonia H.; Sawakuchi, André O.; Cremon, Édipo H.; Mittani, Juan C. R.; Bertani, Thiago C.; Munita, Casimiro J. A. S.; Tudela, Diego R. G.; Yee, Márcio; Moya, Gabriela

    2015-12-01

    The origin of the transcontinental Amazon drainage system remains unrevealed. Sedimentary deposits formed from the Neogene in the Amazonas and Solimões Basins constitute natural archives for reconstructing this event in space and time. However, paleoenvironmental and chronological analyses focusing on these deposits, or even their basic mapping, are still scarce to allow such investigation. In this context, primary interests are fluvial strata related to the lithostratigraphic Içá Formation, mapped over a widespread area in western Amazonian lowlands. Although long regarded as Plio-Pleistocene in age, this unit has not yet been dated and its overall depositional setting remains largely undescribed. The main goal of the present work is to contribute for improving facies analysis and chronology of these deposits, approaching an area in southwestern Amazonia and another in northern Amazonia, which are located more than 1000 km apart. Despite this great distance, the sedimentological and chronological characteristics of deposits from these two areas are analogous. Hence, facies analysis revealed paleoenvironments including active channel, abandoned channel, point bar, crevasse splay and floodplain, which are altogether compatible with meandering fluvial systems. Similarly, optically stimulated luminescence (OSL) dating revealed thirty three ages ranging from 65.4 ± 16.9 to 219.6 ± 25.1 ky (in addition to three outliners of 54.0 ± 7.6, 337.3 ± 36.9 and 346.6 ± 48.6 ky), and nine 97.1 ± 9.9 to 254.8 ± 23.8 ky for the areas in southwestern and northern Amazonia, respectively. These data lead to establish that deposits mapped as Içá Formation over a vast area of western Brazilian Amazonia have a Mid-Late Pleistocene age, rather than the previously inferred Plio-Pleistocene age. It follows that if Plio-Pleistocene deposits exist in this region they remain to be dated and must be restricted to a narrow belt in western Amazonia, as well as isolated occurrences

  2. 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

  3. 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. PMID:21071659

  4. [Keys to families and genera of gerromorpha and nepomorpha (Insecta: Heteroptera) in the central Amazonia, Brazil].

    PubMed

    Pereira, Domingos L V; de Melo, Alan L; Hamada, Neusa

    2007-01-01

    Few studies have been done in Brazil on aquatic and semi-aquatic Gerromorpha and Nepomorpha (Heteroptera), Minas Gerais being the state where these insects have been studied the most. The present study presents keys for identification of Gerromorpha and Nepomorpha adults, thus providing a tool for ecological studies on aquatic insects in Central Amazonia. The specimens used to elaborate the taxonomic keys were collected in Presidente Figueiredo county in streams and artificial lakes and in Manaus county in streams, white-water floodplain (várzea) lakes and Rio Negro black-water flooded forest (igapó). Specimens from the invertebrate collection of the Instituto Nacional de Pesquisas da Amazonia (INPA) were also examined and included in the keys. Thirty one genera from 13 families of the infra-orders mentioned. PMID:17607454

  5. 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.

  6. 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

  7. Is the current stress state in the Central Amazonia caused by surface water loading?

    NASA Astrophysics Data System (ADS)

    Ibanez, Delano M.; Riccomini, Claudio; Miranda, Fernando P.

    2014-11-01

    We present new fault data for the region of the Manaus, Central Amazonia, Brazil. Field measurements concentrate on the Miocene-Holocene sedimentary deposits exposed on the Amazonas River Basin, in order to investigate the development of this region in this time-interval. Two faulting events are distinguished since the Miocene. The oldest one is related to NW-SE extension during Miocene times and associated with paleoseismicity, while the younger is associated with NE-SW extension direction and seems to persist today. These two deformational events may be thereby considered Neotectonic. Moreover, the second extensional pulse with NE-SW orientation can be explained by the surface hydrological loading, which induces the Central Amazonia flexural subsidence and may promote extensional stresses in the upper crust.

  8. 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.

  9. The large-scale biosphere-atmosphere experiment in Amazonia: Analyzing regional land use change effects

    NASA Astrophysics Data System (ADS)

    Keller, Michael; Silva-Dias, Maria Assunção; Nepstad, Daniel C.; Silva-Andreae, Meinrat O.

    The Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) is a multi-disciplinary, multinational scientific project led by Brazil. LBA researchers seek to understand Amazonia in its global context especially with regard to regional and global climate. Current development activities in Amazonia including deforestation, logging, cattle ranching, and agriculture significantly perturb regional and global carbon budgets and the atmospheric radiation budget through both greenhouse gas inputs and the increase in atmospheric particulates generated by fires. The Brazilian Amazon currently releases about 0.2 Pg-C to the atmosphere each year as a result of net deforestation. Logging and forest fire activity are poorly quantified but certainly increase this amount by more than 10%. Fires associated with land management activities generate smoke that leads to heating of the lower atmosphere, decreases in overall cloudiness, increases in cloud lifetimes, and the suppression of rainfall. There are considerable uncertainties associated with our understanding of smoke effects. Present development trends point to agricultural intensification in the Brazilian Amazon. This intensification and the associated generation of wealth present an opportunity to enhance governance on the frontier and to minimize the damaging effects of fires.

  10. 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. PMID:23760636

  11. 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

  12. 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. PMID:18270160

  13. Simulation of rainfall anomalies leading to the 2005 drought in Amazonia using the CLARIS LPB regional climate models

    NASA Astrophysics Data System (ADS)

    Marengo, J.; Chou, S.; Mourao, C.; Solman, S.; Sanchez, E.; Samuelsson, P.; da Rocha, R. P.; Li, L.; Pessacg, N.; Remedio, A. R. C.; Carril, A. F.; F Cavalcanti, I.; Jacob, D.

    2013-12-01

    The meteorological characteristics of the drought of 2005 in Amazonia, one of the most severe in the last 100 years were assessed using a suite of seven regional models obtained from the CLARIS LPB project. The models were forced with the ERA-Interim reanalyses as boundary conditions. We used a combination of rainfall and temperature observations and the low-level circulation and evaporation fields from the reanalyses to determine the climatic and meteorological characteristics of this particular drought. The models reproduce in some degree the observed annual cycle of precipitation and the geographical distribution of negative rainfall anomalies during the summer months of 2005. With respect to the evolution of rainfall during 2004-2006, some of the models were able to simulate the negative rainfall departures during early summer of 2005 (December 2004 to February 2005). The interannual variability of rainfall anomalies for both austral summer and fall over northern and southern Amazonia show a large spread among models, with some of them capable of reproducing the 2005 observed negative rainfall departures (four out of seven models in southern Amazonia during DJF). In comparison, all models simulated the observed southern Amazonia negative rainfall and positive air temperature anomalies during the El Nino-related drought in 1998. The spatial structure of the simulated rainfall and temperature anomalies in DJF and MAM 2005 shows biases that are different among models. While some models simulated the observed negative rainfall anomalies over parts of western and southern Amazonia during DJF, others simulated positive rainfall departures over central Amazonia. The simulated circulation patterns indicate a weaker northeasterly flow from the tropical North Atlantic into Amazonia, and reduced flows from southern Amazonia into the La Plata basin in DJF, which is consistent with observations. In general, we can say that in some degree the regional models are able to

  14. Cloud condensation nuclei in pristine tropical rainforest air of Amazonia:

    NASA Astrophysics Data System (ADS)

    Gunthe, S. S.

    2009-04-01

    Atmospheric aerosol particles serving as cloud condensation nuclei (CCN) are key elements of the hydrological cycle and climate. We have measured and characterized CCN at water vapor supersaturations in the range of S = 0.10-0.82% in pristine tropical rainforest air during the AMAZE-08 campaign in central Amazonia. The effective hygroscopicity parameters describing the influence of chemical composition on the CCN activity of aerosol particles varied in the range of ΰ = 0.05-0.45. The overall median value of ΰ ? 0.15 was only half of the value typically observed for continental aerosols in other regions of the world. Aitken mode particles were less hygroscopic than accumulation mode particles (ΰ ? 0.1 at D ? 50 nm; ΰ ? 0.2 at D ? 200 nm). The CCN measurement results were fully consistent with aerosol mass spectrometry (AMS) data, which showed that the organic mass fraction (Xm,org) was on average as high as ~90% in the Aitken mode (D ? 100 nm) and decreased with increasing particle diameter in the accumulation mode (~80% at D ? 200 nm). The ΰ values exhibited a close linear correlation with Xm,org and extrapolation yielded the following effective hygroscopicity parameters for organic and inorganic particle components: ΰorg ? 0.1 which is consistent with laboratory measurements of secondary organic aerosols and ΰinorg ? 0.6 which is characteristic for ammonium sulfate and related salts. Both the size-dependence and the temporal variability of effective particle hygroscopicity could be parameterized as a function of AMS-based organic and inorganic mass fractions (ΰp = 0.1 Xm,org + 0.6Xm,inorg), and the CCN number concentrations predicted with ΰp were in fair agreement with the measurement results. The median CCN number concentrations at S = 0.1-0.82% ranged from NCCN,0.10 ? 30 cm-3to NCCN,0.82 ? 150 cm-3, the median concentration of aerosol particles larger than 30 nm was NCN,30 ? 180 cm-3, and the corresponding integral CCN efficiencies

  15. 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. PMID:27600657

  16. 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)

  17. Phenotypic effects of an induced mutation of the ObRa isoform of the leptin receptor★

    PubMed Central

    Li, Zhiying; Ceccarini, Giovanni; Eisenstein, Michael; Tan, Keith; Friedman, Jeffrey Michael

    2013-01-01

    Leptin receptors play critical roles in mediating leptin's pleiotropic effects on mammalian physiology. To date, six splice variants of the leptin receptor gene have been identified [1–3]. These splice variants have identical extracellular leptin binding motifs but different intracellular C termini. The finding that mutations specifically ablating the function of ObRb cause obesity has established a critical role for this isoform in leptin signaling [1,7]. ObRa is the most abundant splicing isoform with a broad tissue distribution [5], and it has been proposed to play roles in regulating leptin bioavailability, CSF (cerebrospinal fluid) transport and function by forming heterodimers with ObRb and also activating signal transduction via JAK2 in-vitro [5–10]. To assess the in-vivo role of ObRa, we generated an ObRa KO mouse by deleting the ObRa-specific exon 19a. Homozygous mutant mice breed normally and are indistinguishable from wild-type mice on regular chow diet, but show a slightly increased basal plasma leptin, a slight improvement of their GTT and a slightly reduced response to systemic leptin administration. These mice also show a modest but statistically significant increase in weight when placed on a high fat diet with a slightly reduced CSF/plasma ratio of leptin. These data suggest that ObRa plays a role in mediating some of leptin's effects but that the phenotypic consequences are modest compared to a deletion of ObRb. PMID:24327953

  18. 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

  19. 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. PMID:25002502

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. Visible and infrared spin scan radiometer atmospheric sounder water vapor and wind fields over Amazonia

    SciTech Connect

    Schmit, T.J.; Brueske, K.F.; Smith, W.L. ); Menzel, W.P. )

    1990-09-20

    Both the mass and motion fields for Amazonia have been depicted using almost exclusively geostationary satellite data. Derived parameters include satellite retrievals of atmospheric temperature and dewpoint temperature, total precipitable water vapor, and cloud and water vapor winds. The capabilities of geostationary satellite data have been demonstrated at least four times a day for the period of May 5-8, 1987, during the Global Tropospheric Experiment/Amazon Boundary Layer Experiment. The satellite-derived information is able to resolve synoptic-scale atmospheric trends in space and time.

  7. Amber from western Amazonia reveals Neotropical diversity during the middle Miocene

    PubMed Central

    Antoine, Pierre-Olivier; De Franceschi, Dario; Flynn, John J.; Nel, André; Baby, Patrice; Benammi, Mouloud; Calderón, Ysabel; Espurt, Nicolas; Goswami, Anjali; Salas-Gismondi, Rodolfo

    2006-01-01

    Tertiary insects and arachnids have been virtually unknown from the vast western Amazonian basin. We report here the discovery of amber from this region containing a diverse fossil arthropod fauna (13 hexapod families and 3 arachnid species) and abundant microfossil inclusions (pollen, spores, algae, and cyanophyceae). This unique fossil assemblage, recovered from middle Miocene deposits of northeastern Peru, greatly increases the known diversity of Cenozoic tropical–equatorial arthropods and microorganisms and provides insights into the biogeography and evolutionary history of modern Neotropical biota. It also strengthens evidence for the presence of more modern, high-diversity tropical rainforest ecosystems during the middle Miocene in western Amazonia. PMID:16950875

  8. 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.

  9. 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. PMID:12656130

  10. 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

  11. 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

    2013-06-01

    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. PMID:23610169

  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 PMID:8703102

  13. 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

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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

    2016-01-01

    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

  19. 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. PMID:25075790

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

    PubMed Central

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

    2013-01-01

    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 km2 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. PMID:23610169

  1. 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. PMID:15984060

  2. 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

  3. 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.

  4. 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.

  5. 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. PMID:26030879

  6. Statistical and wavelet analysis of the ATTO experiment in Amazonia rainforest

    NASA Astrophysics Data System (ADS)

    Bolzan, Mauricio

    The study of the turbulence over a roughness surface is the most important subject in exchange of the gases between surface and atmosphere. This fact turns most important over surfaces like the Amazonia rainforest due its importance on local and regional climate. The Amazon Tall Tower Observatory - ATTO started its in February, 2012, with 10 dimensional ultrasonic anemometers bi and tri, in an 80 m tower of height. These anemometers were positioned in 78 m; 70 m; 62 m; 41 m; 57 m; 50 m; 45 m; 36 m; 30 m and 23 m of height and collected data were sampled at 1 Hz, 4 Hz and 10 Hz. The quadrant analysis and Wavelet transform were used to study the behavior of the Coherent Structure (CSs) over the Amazonia forest canopy in different atmospheric stability conditions. The results showed a fairly unique feature of the vertical wind profile near and below the inflection point. According to observations, the geometry of the canopy and terrain contributed to main influences for this aerodynamic effect of wind profile, as well as for the formation of coherent structures like "rolls" on the forest canopy in ATTO-CLAIRE site.

  7. Aerosols in Amazonia: Natural biogenic particles and large scale biomass burning impacts

    NASA Astrophysics Data System (ADS)

    Artaxo, Paulo; Barbosa, Henrique M. J.; Rizzo, Luciana V.; Brito, Joel F.; Sena, Elisa T.; Cirino, Glauber G.; Arana, Andrea

    2013-05-01

    The Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA) is a long term (20 years) research effort aimed at the understanding of the functioning of the Amazonian ecosystem. In particular, the strong biosphere-atmosphere interaction is a key component looking at the exchange processes between vegetation and the atmosphere, focusing on aerosol particles. Two aerosol components are the most visible: The natural biogenic emissions of aerosols and VOCs, and the biomass burning emissions. A large effort was done to characterize natural biogenic aerosols that showed detailed organic characterization and optical properties. The biomass burning component in Amazonia is important in term of aerosol and trace gases emissions, with deforestation rates decreasing, from 27,000 Km2 in 2004 to about 5,000 Km2 in 2011. Biomass burning emissions in Amazonia increases concentrations of aerosol particles, CO, ozone and other species, and also change the surface radiation balance in a significant way. Long term monitoring of aerosols and trace gases were performed in two sites: a background site in Central Amazonia, 55 Km North of Manaus (called ZF2 ecological reservation) and a monitoring station in Porto Velho, Rondonia state, a site heavily impacted by biomass burning smoke. Several instruments were operated to measured aerosol size distribution, optical properties (absorption and scattering at several wavelengths), composition of organic (OC/EC) and inorganic components among other measurements. AERONET and MODIS measurements from 5 long term sites show a large year-to year variability due to climatic and socio-economic issues. Aerosol optical depths of more than 4 at 550nm was observed frequently over biomass burning areas. In the pristine Amazonian atmosphere, aerosol scattering coefficients ranged between 1 and 200 Mm-1 at 450 nm, while absorption ranged between 1 and 20 Mm-1 at 637 nm. A strong seasonal behavior was observed, with greater aerosol loadings during the

  8. Precipitation extremes over Amazonia - atmospheric and oceanic associated features observed and simulated by HADGEM2-ES, CPTEC/INPE AGCM and Eta/CPTEC regional model

    NASA Astrophysics Data System (ADS)

    Cavalcanti, I. F.

    2013-05-01

    Extreme monthly cases of precipitation (positive and negative anomalies) over Amazonia are analyzed to show the atmospheric and oceanic related features and the ability of CPTEC AGCM and HADGEM2-ES in simulating them. Humidity flux variability over the Tropical Atlantic region is analyzed related to the precipitation variability over Amazonia. Besides the Pacific Ocean influence, the Amazonia precipitation is affected by the Tropical Atlantic Ocean, both by the SST and atmospheric flux humidity. Correlations between Atlantic SST and Amazonia precipitation show that there are specific months and areas that are affected by SST anomalies. The extreme cases are obtained from the Standardized Precipitation Index (SPI) applied to monthly data in four areas of Amazonia: northwest, northeast, west and east areas. The period of analysis is 1981 to 2010 to GPCP observed precipitation and CPTEC/INPE AGCM. As this AGCM is the base of the Brazilian Model of Earth System, its behavior on the mechanisms leading to extremes over Amazonia, compared to observations is discussed. Projections of extremes over the region are analyzed with results from CMIP5 HADGEM2-ES during 2073-2099 compared to 1979-2005. The regional Eta CPTEC model is also analyzed in two periods: 1960 to 1990 and 2040 to 2070, with boundary conditions of CMIP3 HADCM3 A1B scenario. The relevance of this analysis is to identify changes in frequency and intensity of extremes in the Amazon region in a higher resolution than the global models.

  9. 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

  10. Diet of a free-ranging group of squirrel monkeys (Saimiri sciureus) in eastern Brazilian Amazonia.

    PubMed

    Lima, Eldianne M; Ferrari, Stephen F

    2003-01-01

    The feeding behaviour of free-ranging Saimiri sciureus was monitored over a 6-month period in eastern Brazilian Amazonia. Behavioural data were collected in scan samples (7-9 days per month), and fruit and arthropod availability were recorded monthly. A total of 3,546 feeding records were collected, divided between reproductive plant parts (55.1%) and arthropods (44.9%). The majority of identified prey were orthopterans and lepidopterans, and 10 of the 23 plant species exploited were Leguminosae and Sapotaceae. The diet varied progressively between August (20.0% plant, 80.0% animal) and January (79.7% plant, 20.3% animal). This shift accompanied an increase in the number of fruiting trees and evidence of declining arthropod availability. This included a marked reduction in foraging success and increasing consumption of immature prey. Overall, the data indicate that Amazonian squirrel monkeys may be relatively frugivorous during periods when prey is scarce. PMID:12826734

  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. PMID:24165869

  12. 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

    2013-06-01

    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

  13. 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. PMID:18767122

  14. 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.

  15. 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

  16. Genetic footprints of demographic expansion in North America, but not Amazonia, during the Late Quaternary.

    PubMed

    Lessa, Enrique P; Cook, Joseph A; Patton, James L

    2003-09-01

    The biotic consequences of climate change have attracted considerable attention. In particular, the "refugial debate" centers on the possible retraction of habitats to limited areas that may have served as refuges for many associated species, especially during glaciations of the Quaternary. One prediction of such scenarios is that populations must have experienced substantial growth accompanying climatic amelioration and the occupation of newly expanded habitats. We used coalescence theory to examine the genetic evidence, or lack thereof, for late Pleistocene refugia of boreal North American and tropical Amazonian mammals. We found substantial and concordant evidence of demographic expansion in North American mammals, particularly at higher latitudes. In contrast, small mammals from western Amazonia appear to have experienced limited or no demographic expansion after the Late Pleistocene. Thus, demographic responses to climate change can be tracked genetically and appear to vary substantially across the latitudinal gradient of biotic diversity. PMID:12913123

  17. 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

  18. 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. PMID:26132139

  19. Effects of reduced-impact logging on fish assemblages in central Amazonia.

    PubMed

    Dias, Murilo S; Magnusson, William E; Zuanon, Jansen

    2010-02-01

    In Amazonia reduced-impact logging, which is meant to reduce environmental disturbance by controlling stem-fall directions and minimizing construction of access roads, has been applied to large areas containing thousands of streams. We investigated the effects of reduced-impact logging on environmental variables and the composition of fish in forest streams in a commercial logging concession in central Amazonia, Amazonas State, Brazil. To evaluate short-term effects, we sampled 11 streams before and after logging in one harvest area. We evaluated medium-term effects by comparing streams in 11 harvest areas logged 1-8 years before the study with control streams in adjacent areas. Each sampling unit was a 50-m stream section. The tetras Pyrrhulina brevis and Hemigrammus cf. pretoensis had higher abundances in plots logged > or =3 years before compared with plots logged <3 years before. The South American darter (Microcharacidium eleotrioides) was less abundant in logged plots than in control plots. In the short term, the overall fish composition did not differ two months before and immediately after reduced-impact logging. Temperature and pH varied before and after logging, but those differences were compatible with normal seasonal variation. In the medium term, temperature and cover of logs were lower in logged plots. Differences in ordination scores on the basis of relative fish abundance between streams in control and logged areas changed with time since logging, mainly because some common species increased in abundance after logging. There was no evidence of species loss from the logging concession, but differences in log cover and ordination scores derived from relative abundance of fish species persisted even after 8 years. For Amazonian streams, reduced-impact logging appears to be a viable alternative to clear-cut practices, which severely affect aquatic communities. Nevertheless, detailed studies are necessary to evaluated subtle long-term effects. PMID

  20. 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.

  1. 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

  2. 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. PMID:27121257

  3. Refining Rodinia: New Paleomagnetic Results From Amazonia and Paleogeographic Implications For The Grenville Orogeny.

    NASA Astrophysics Data System (ADS)

    Tohver, E.; van der Pluijm, B. A.; van der Voo, R.

    The Grenville province of eastern Laurentia is commonly considered to be the product of continental collision between ancestral North America and an as yet unidentified continent. New paleogeographic information for the Amazon craton in early Grenvil- lian times was determined from a new paleomagnetic pole based on the hypabyssal gabbros and flat-lying basalts of the Nova Floresta Fm. found in the western Brazil- ian state of Rondonia. Measurement of the anisotropy of magnetic susceptibility of the gabbros reveals a flat-lying fabric, suggesting an undeformed, igneous body. A paleomagnetic pole (n = 16 sites, Plat = 24.6N, Plon. = 164.6E, A95 = 5.5, Q = 5) is calculated from a steep, characteristic remanence (ChRM) that is inferred to be primary. This ChRM is isolated at applied field >30 mT and is probably carried by magnetite present in large, oxyexsolved titanomagnetites or igneous reaction rims. Emplacement of the body and acquisition of magnetization is dated by 40Ar/39Ar analysis of igneous biotite and plagioclase, both phases yielding ages of ca.1.2 Ga. Comparison of the position of Amazonia with that of ancestral North America deter- mined from the Laurentian APWP from 1.3 - 1.15 Ga suggests that Amazonia may have collided with the southernmost portion of Laurentia at ca.1.2 Ga. The timing of this collision is in agreement with geochronological constraints on the timing of de- formation in the Llano segment of Laurentia as well as observed deformation of the western Amazon craton.

  4. Influence of Peruvian flat-subduction dynamics on the evolution of western Amazonia

    NASA Astrophysics Data System (ADS)

    Eakin, Caroline M.; Lithgow-Bertelloni, Carolina; Dávila, Federico M.

    2014-10-01

    Convection in the Earth's mantle is mainly driven by cold, dense subducting slabs, but relatively little is known about how 3D variations in slab morphology and buoyancy affect mantle flow or how the surface above deforms in response (i.e. dynamic topography). We investigate this problem by studying the dynamics of an active region of flat-slab subduction located in Peru in South America. Here the slab geometry is well known, based on the regional seismicity, and we have observations from the local geological record to validate our models. Of particular interest is the widespread subsidence and deposition of the Solimões Formation across western Amazonia that coincided with the development of the Peruvian flat-slab during the Mid-Late Miocene. This formation covers an extensive area from the foredeep to the Purus Arch located ∼2000 km away from the trench. Close to the Andes the preservation of several kilometers of sedimentary thicknesses can be easily accounted for by flexure. Based on an estimate of the Andean loading we predict 2.8 to 3.6 km of accommodation space that spans 100 km. The spatial and temporal history of the Solimões Formation however, particularly the thick distal foreland accumulations up to 1.2 km deep, can only be matched with the addition of a longer-wavelength dynamic source of topography. Following the transition from normal to flat subduction, we predict over 1 km of dynamic subsidence (∼1500 km wide) that propagates over 1000 km away from the trench, tracking the subduction leading edge. This is followed by a pulse of dynamic uplift over the flat segment behind it. We therefore propose that a combination of uplift, flexure and dynamic topography during slab flattening in Peru is responsible for the sedimentation history and landscape evolution of western Amazonia that eventually led to the configuration of the Amazon Drainage Basin we know today.

  5. Aerosol Chemical and Physical Characterization in Central Amazonia during the 2013 Dry Season

    NASA Astrophysics Data System (ADS)

    Artaxo, P.; Stern, R.; Brito, J.; Carbone, S.

    2015-12-01

    During the dry season, the central Amazon forest is highly influenced by forest fires transported through large distances, changing drastically the atmospheric composition even in remote places. This work focuses on a physical-chemical characterization of the aerosol population over a pristine site in Central Amazonia during the dry season. The submicrometer organic aerosols were measured with the Aerodyne ACSM (Aerosol Chemical Speciation Monitor, Aerodyne Inc). Optical properties, size distribution and other micro-physical characteristics were also analyzed. Other instruments were simultaneously used. The measurements were taken during the dry season of 2013 in the Cuieiras ecological reserve (ZF2), northwest of Manaus. The statistical analysis of the data was done with the PMF (Positive Matrix Factorization) technique, in which the organic aerosol was separated into different factors, and then its sources and forming processes were attributed. Results show that the mean aerosol loading was 5,91 μg m-3, from which 78% are of organic composition, 8.5% are sulfate, 6.5% are equivalent black carbon, 4% are ammonium and 3% are nitrate. The mass spectra variability can be explained by 3 factors only, determined with the PMF technique. They were identified as BBOA (Biomass Burning Organic Aerosol), representing 12% of the total organic mass, OOA (Oxygenated Organic Aerosol), representing 66% of the total organic mass and IEPOX-SOA (Isoprene derived Epoxydiol-Secondary Organic Aerosol), representing 21% of the total organic mass. Even in remote and pristine regions, Central Amazonia is highly impacted by biomass burning. Biogenic secondary organic aerosols are also present during the dry season, and the suppression of its wet deposition processes increases their concentration. The oxidation level and other physical-chemical characteristics indicate that the long range transport is responsible for the regional range of this impact.

  6. 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

  7. 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

  8. 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.

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

    NASA Astrophysics Data System (ADS)

    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 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.

  10. 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

  11. 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

  12. Stormflow runoff in Eastern Amazonia, Brazil: The role of riparian wetland valleys

    NASA Astrophysics Data System (ADS)

    Wickel, A. J.; van de Giesen, N. C.

    2005-12-01

    Analysis of 245 rainfall-runoff events over a one and a half year study period at two small (10 and 35 ha.) watersheds in the Eastern Amazon region revealed a strong correlation between rainfall and stormflow volume. From this relationship it was deducted that only 0.6% of the total watershed area is estimated to contribute to stormflow generation, while only 1.5 % of the total annual runoff is made up by stormflow. The main factors controlling stormflow generation seem to be topography (shallow canyon like incision pattern of the creeks), which confines the source area of stormflow to the flat valley bottoms with riparian forest, and the high permeability of the surrounding area. Analysis of field measurements revealed that the minimum observed infiltration rate (80 mm/hr) still exceeds the maximum rainfall rates (66 mm/hr), meaning that saturation overland flow or Hortonian overland flow conditions hardly ever occur. Similar stormflow dynamics were found for catchments with comparable topography and soil characteristics in various studies in Central Amazonia and for a watershed in Guyana. In none of these studies though, the relation between rainfall and stormflow was so strong that even the filling of the wetland storage with the onset of the rainy season could be observed. The hypothesis of a fixed contributing area for the streams of the current study region is confirmed by the chemical analysis of stormflow nutrient concentrations, which seems to be entirely controlled by the riparian vegetation. After a short period of strong flushing of nutrients from the canopy at the onset of the rainy season the stormflow shows only a slight decline in nutrient concentrations. A second, delayed peak in stream nutrient exports, typical for overland flow during or right after a storm, was absent. The current study illustrates that the variable source concept posed by Hewlett and Hibbert in 1967 is limited by topography and substrate under certain conditions, and that the

  13. Seasonality of Isoprenoid Vertical Gradient Within a Primary Rainforest in Central Amazonia

    NASA Astrophysics Data System (ADS)

    Alves, E. G.; Jardine, K.; Tota, J.; Jardine, A. B.; Yanez-Serrano, A. M.; Karl, T.; Guenther, A. B.; Tavares, J. V.; Nelson, B. W.

    2014-12-01

    Vertical mixing ratio gradients of isoprene, total monoterpenes (TMt) and total sesquiterpenes (TSt) were quantified, within and above the canopy, in a primary rainforest in central Amazonia , using a Proton Transfer Reaction - Mass Spectrometer (PTR-MS). We also estimated the fluxes of these compounds from the canopy into the atmosphere. Measurements were carried out from the dry season (Sept/2010) to the wet season (Jan/2011), continuously. All compound mixing ratios were higher during the dry season than during the wet season; the same behavior was observed for ambient air temperature and photosynthetically active radiation (PAR). Isoprene and TMt mixing ratios were higher within the canopy as compared to near the ground and above the canopy. Daytime TSt mixing ratios were higher near the ground than within and above the canopy. Isoprene and TMt had a diurnal cycle similar to diurnal cycles of air temperature and PAR suggesting that the emission of these compounds are light dependent and stimulated by increasing temperature. However, this same behavior was not observed for TSt. This is probably due to the fact that sesquiterpene emissions are not strongly light dependent; the ozonolysis of sesquiterpenes during daytime could reduce ambient sesquiterpene concentrations; and a less turbulent atmospheric boundary layer during nighttime could make the mixing ratio of sesquiterpenes higher near the surface at nighttime. Daytime flux estimations also presented seasonal variation for the fluxes of all compounds, such that fluxes of: isoprene ranged from 0.4 to 1.5 mg m-2 h-1, TMt ranged from 0.2 to 0.8 mg m-2 h-1, and TSt ranged from 0.1 to 0.25 mg m-2 h-1, being the highest end during the dry season. These flux estimations suggested that the canopy could be the main source of those compounds for the atmosphere for all seasons. Our results provide the first in situ observations of seasonal mixing ratio gradients of isoprenoids in central Amazonia, and suggest that some

  14. Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia

    NASA Astrophysics Data System (ADS)

    Rummel, U.; Ammann, C.; Kirkman, G. A.; Moura, M. A. L.; Foken, T.; Andreae, M. O.; Meixner, F. X.

    2007-10-01

    Within the project EUropean Studies on Trace gases and Atmospheric CHemistry as a contribution to Large-scale Biosphere-atmosphere experiment in Amazonia (LBA-EUSTACH), we performed tower-based eddy covariance measurements of O3 flux above an Amazonian primary rain forest at the end of the wet and dry season. Ozone deposition revealed distinct seasonal differences in the magnitude and diel variation. In the wet season, the rain forest was an effective O3 sink with a mean daytime (midday) maximum deposition velocity of 2.3 cm s-1, and a corresponding O3 flux of -11 nmol m-2 s-1. At the end of the dry season, the ozone mixing ratio was about four times higher (up to maximum values of 80 ppb) than in the wet season, as a consequence of strong regional biomass burning activity. However, the typical maximum daytime deposition flux was very similar to the wet season. This results from a strong limitation of daytime O3 deposition due to reduced plant stomatal aperture as a response to large values of the specific humidity deficit. As a result, the average midday deposition velocity in the dry burning season was only 0.5 cm s-1. The large diel ozone variation caused large canopy storage effects that masked the true diel variation of ozone deposition mechanisms in the measured eddy covariance flux, and for which corrections had to be made. In general, stomatal aperture was sufficient to explain the largest part of daytime ozone deposition. However, during nighttime, chemical reaction with nitrogen monoxide (NO) was found to contribute substantially to the O3 sink in the rain forest canopy. Further contributions were from non-stomatal plant uptake and other processes that could not be clearly identified. Measurements, made simultaneously on a 22 years old cattle pasture enabled the spatially and temporally direct comparison of O3 dry deposition values from this site with typical vegetation cover of deforested land in southwest Amazonia to the results from the primary rain

  15. Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia

    NASA Astrophysics Data System (ADS)

    Rummel, U.; Ammann, C.; Kirkman, G. A.; Moura, M. A. L.; Foken, T.; Andreae, M. O.; Meixner, F. X.

    2007-05-01

    Within the project EUropean Studies on Trace gases and Atmospheric CHemistry as a contribution to Large-scale Biosphere-atmosphere experiment in Amazonia (LBA-EUSTACH), we performed tower-based eddy covariance measurements of O3 flux above an Amazonian primary rain forest at the end of the wet and dry seasons. Ozone deposition revealed distinct seasonal differences in the magnitude and diel variation. In the wet season, the rain forest was an effective O3 sink with a mean daytime (midday) maximum deposition velocity of 2.3 cm s-1, and a corresponding O3 flux of -11 nmol m-2 s-1. At the end of the dry season, the ozone mixing ratio was about four times higher (up to maximum values of 80 ppb) than in the wet season, as a consequence of strong regional biomass burning activity. However, the typical maximum daytime deposition flux was very similar to the wet season. This results from a strong limitation of daytime O3 deposition due to reduced plant stomatal aperture as a response to large values of the specific humidity deficit. As a result, the average midday deposition velocity in the dry burning season was only 0.5 cm s-1. The large diel ozone variation caused large canopy storage effects that masked the true diel variation of ozone deposition mechanisms in the measured eddy covariance flux, and for which corrections had to be made. In general, stomatal aperture was sufficient to explain the largest part of daytime ozone deposition. However, during nighttime, chemical reaction with nitrogen monoxide (NO) was found to contribute substantially to the O3 sink in the rain forest canopy. Further contributions were from non-stomatal plant uptake and other processes that could not be clearly identified. Measurements, made simultaneously on a 22 years old cattle pasture enabled the spatially and temporally direct comparison of O3 dry deposition values from this site with typical vegetation cover of deforested land in southwest Amazonia to the results from the primary rain

  16. Epidemiology of Disappearing Plasmodium vivax Malaria: A Case Study in Rural Amazonia

    PubMed Central

    Lima, Nathália F.; Batista, Camilla L.; Bastos, Melissa da Silva; Nicolete, Vanessa C.; Fontoura, Pablo S.; Gonçalves, Raquel M.; Viana, Susana Ariane S.; Menezes, Maria José; Scopel, Kézia Katiani G.; Cavasini, Carlos E.; Malafronte, Rosely dos Santos; da Silva-Nunes, Mônica; Vinetz, Joseph M.; Castro, Márcia C.; Ferreira, Marcelo U.

    2014-01-01

    Background New frontier settlements across the Amazon Basin pose a major challenge for malaria elimination in Brazil. Here we describe the epidemiology of malaria during the early phases of occupation of farming settlements in Remansinho area, Brazilian Amazonia. We examine the relative contribution of low-density and asymptomatic parasitemias to the overall Plasmodium vivax burden over a period of declining transmission and discuss potential hurdles for malaria elimination in Remansinho and similar settings. Methods Eight community-wide cross-sectional surveys, involving 584 subjects, were carried out in Remansinho over 3 years and complemented by active and passive surveillance of febrile illnesses between the surveys. We used quantitative PCR to detect low-density asexual parasitemias and gametocytemias missed by conventional microscopy. Mixed-effects multiple logistic regression models were used to characterize independent risk factors for P. vivax infection and disease. Principal Findings/Conclusions P. vivax prevalence decreased from 23.8% (March–April 2010) to 3.0% (April–May 2013), with no P. falciparum infections diagnosed after March–April 2011. Although migrants from malaria-free areas were at increased risk of malaria, their odds of having P. vivax infection and disease decreased by 2–3% with each year of residence in Amazonia. Several findings indicate that low-density and asymptomatic P. vivax parasitemias may complicate residual malaria elimination in Remansinho: (a) the proportion of subpatent infections (i.e. missed by microscopy) increased from 43.8% to 73.1% as P. vivax transmission declined; (b) most (56.6%) P. vivax infections were asymptomatic and 32.8% of them were both subpatent and asymptomatic; (c) asymptomatic parasite carriers accounted for 54.4% of the total P. vivax biomass in the host population; (d) over 90% subpatent and asymptomatic P. vivax had PCR-detectable gametocytemias; and (e) few (17.0%) asymptomatic and subpatent P

  17. 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

  18. Tersilochinae of Western Amazonia (Hymenoptera: Ichneumonidae). Genus Stethantyx Townes, part 1.

    PubMed

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

    2013-01-01

    Sixteen species of the genus Stethantyx Townes having first and second sections of radius meeting at obtuse angle are recorded from Peru and Ecuador in Western Amazonia. Ten species, S. amazonica Khalaim & Sääksjärvi, sp. nov., S. aurantia Khalaim & Sääksjärvi, sp. nov., S. juninensis Khalaim & Bordera, sp. nov., S. loretosa Khalaim & Sääksjärvi, sp. nov., S. neopropodeator Khalaim & Sääksjärvi, sp. nov., S. orellana Khalaim & Sääksjärvi, sp. nov., S. sinuata Khalaim & Sääksjärvi, sp. nov., S. tiputinia Khalaim & Sääksjärvi, sp. nov., S. trepida Khalaim & Sääksjärvi, sp. nov. and S. voluptaria Khalaim & Sääksjärvi, sp. nov., are described as new. Six species, previously known only from Costa Rica,           S. alajuela Khalaim & Broad, S. heredia Khalaim & Broad, S. orosia Khalaim & Broad, S. propodeator Khalaim & Broad, S. puntarenasa Khalaim & Broad and S. sanjosea Khalaim & Broad, are recorded from South America for the first time. A partial key to Western Amazonian species of Stethantyx is given. PMID:25112992

  19. 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

  20. 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. PMID:25793602

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

    PubMed

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

    2015-01-01

    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. PMID:26249980

  2. 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

  3. 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.

    2016-04-01

    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.

  4. Tropical Continental Convection (Amazonia and the North American Monsoon): Unique Observations from GPS Meteorological Networks

    NASA Astrophysics Data System (ADS)

    Adams, D. K.

    2015-12-01

    The complex interactions/feedbacks between water vapor fields and deep atmospheric convection remain one of the outstanding problems in Tropical Meteorology. The lack of high spatial/temporal resolution, all-weather observations in the Tropics has hampered progress. In this talk, we present results employing GPS meteorology from two topographically/climatologically unique Tropical Continental regimes: Central Amazonia and the Sierra Madre Occidental of Mexico. Specifically, we presents results on the shallow-to-deep convective transition from both regimes in addition to employing water vapor convergence as a proxy variable for convective intensity. Results from both convective regimes reveal an approximately 4-hour timescale of intense water vapor convergence associated with the transition from shallow to deep precipitating convection. This water vapor convergence time scale provides a useful metric for both high resolution and global climate models to replicate. Furthermore, we examime convective intensity from both regimes (defined utilizing lightning data, cloud top temperature or precipitation), which is also characterized by the time-rate-of-change of precipitable water vapor. The relationship between the time-rate-of-change of precipitable water vapor and convective intensity is positive, however, with a large amount spread in the data and some dependence on the regime and topography.

  5. 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.

  6. 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.

  7. 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

  8. Open access to information bridges science and development in Amazonia: lessons of the SIAMAZONIA service

    NASA Astrophysics Data System (ADS)

    Kalliola, Risto; Toivonen, Tuuli; Miyakawa, Victor; Mavila, Manuel

    2008-07-01

    Access to and availability of accurate information has often been stated to play an important role in sustainable environmental management. There is a growing trend of setting up internet-based information services to support the availability of relevant information. The current initiatives that aim to facilitate such information sharing through the web are still, however, often premature and unable to ensure constant flow of data from producers to users. We examine these common challenges by using as an example a network-based facility of biodiversity and environmental information about the Peruvian Amazon region called SIAMAZONIA. Launched in 2001, the service includes data provided by 13 different nodes. The experiences of this initiative have been both encouraging and confusing. A good professional level has been reached, but participation by large information holders is impeded. Participation is obviously considered an additional task rather than an attractive option for enhanced performance at the individual or institutional levels. This dilemma reflects a genuine problem in the modern scientific community, which still lacks agreed ways to reward those who share their data and results through the web. If these problems are solved, internet-based information sharing may become a vital resource for environmental management in Amazonia and also elsewhere.

  9. The Cotingo Dam as a test of Brazil's system for evaluating proposed developments in Amazonia

    NASA Astrophysics Data System (ADS)

    Fearnside, Philip M.; Barbosa, Reinaldo Imbrozio

    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.

  10. Party size and diet of syntopic atelids (Ateles chamek and Lagothrix cana) in Southwestern Brazilian Amazonia.

    PubMed

    Iwanaga, S; Ferrari, S F

    2001-01-01

    Syntopic Alouatta seniculus, Ateles chamek and Lagothrix cana (Atelidae) were studied in southwestern Amazonia. Primate populations were first surveyed, and then the party size, diet and vertical spacing were monitored over a 5-month period. Atelids accounted for more than half the survey sightings and Lagothrix was the most abundant. Party sizes recorded for both Alouatta and Lagothrix during monitoring were significantly larger than those recorded during surveys, but no such difference was found for Ateles. Monitored parties were significantly larger in Lagothrix in comparison with either Alouatta or Ateles, as were groups of Ateles in comparison with Alouatta. Mean party size in Ateles decreased progressively during the course of the study, from 8.9 +/- 3.4 in June to 3.9 +/- 2.3 in October. Moraceae was the most important dietary resource for Ateles and Lagothrix, in terms of both feeding records and number of species exploited. There was considerable overlap in the plant taxa exploited, but some notable differences, such as the exclusive use of Hymenaea courbaril (Caesalpinaceae) by Lagothrix and of Euterpe precatoria (Arecaceae) by Ateles. As at other sites in the region, Ateles occupied significantly higher forest strata in comparison with Lagothrix. Despite the preliminary nature of the study, the results indicate a number of ecological differences between species that undoubtedly play an important role in niche separation. PMID:11713409

  11. Vegetation and hydrology changes in Eastern Amazonia inferred from a pollen record.

    PubMed

    Toledo, Mauro B de; Bush, Mark B

    2008-03-01

    Pollen, charcoal, and C14 analyses were performed on a sediment core obtained from Lake Tapera (Amapá) to provide the palaeoenvironmental history of this part of Amazonia. A multivariate analysis technique, Detrended Correspondence Analysis, was applied to the pollen data to improve visualization of sample distribution and similarity. A sedimentary hiatus lasting 5,500 years was identified in the Lake Tapera. Because the timing of the hiatus overlapped with the highest Holocene sea-level, which would have increased the local water table preventing the lake from drying out, it is clear that sea-level was not important in maintaining the lake level. Lake Tapera probably depended on riverine flood waters, and the sedimentary gap was caused by reduced Amazon River discharge, due to an extremely dry period in the Andes (8,000-5,000 years BP), when precipitation levels markedly decreased. The lack of Andean pollen (river transported) in the record after this event supports this interpretation. The pollen analysis shows that when sedimentation resumed in 1,620 cal. years BP, the vegetation around the lake was changed from forest into savanna. This record demonstrates the need to improve our understanding of climate changes and their associated impacts on vegetation dynamics. PMID:18345387

  12. 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. PMID:26247467

  13. 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. PMID:26174960

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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 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.

  16. Modeling small watersheds in Brazilian Amazonia with shuttle radar topographic mission-90 m data

    NASA Astrophysics Data System (ADS)

    Valeriano, Márcio M.; Kuplich, Tatiana M.; Storino, Moisés; Amaral, Benedito D.; Mendes, Jaime N.; Lima, Dayson J.

    2006-10-01

    This work presents a methodology for the refinement of shuttle radar topographic mission (SRTM-90 m) data available for South America to enable detailed watershed studies in Amazonia. The original data were pre-processed to properly map detailed low-order drainage features and allowed digital estimates of morphometric variables. Spatial-resolution refinement (3″ to 1″, or ˜90 to ˜30 m) through data kriging was found to be an interesting solution to construct digital elevation models (DEMs) with more adequate presentation of landforms than the original data. The refinement of spatial resolution by kriging interpolation overcame the main constraints for drainage modeling with original SRTM-90 m, such as spatial randomness, artifacts and unrealistic presentation due to pixel size. Kriging with a Gaussian semivariogram model caused a smoothing of the resulting DEM, but the main features for drainage modeling were preserved. Canopy effects on the modeled surface represented the main remaining limitation for terrain analysis after pre-processing. Data regarding a small watershed in Amazonas (˜38 km 2), Brazil, were evaluated through visualization techniques, morphometric analyses and plot diagrams of the results. The data showed limitations for use in the original form, but could be applied for watershed modeling at relatively detailed scales after the described pre-processing.

  17. The distribution and amount of carbon in the largest peatland complex in Amazonia

    NASA Astrophysics Data System (ADS)

    Draper, Frederick C.; Roucoux, Katherine H.; Lawson, Ian T.; Mitchard, Edward T. A.; Honorio Coronado, Euridice N.; Lähteenoja, Outi; Torres Montenegro, Luis; Valderrama Sandoval, Elvis; Zaráte, Ricardo; Baker, Timothy R.

    2014-12-01

    Peatlands in Amazonian Peru are known to store large quantities of carbon, but there is high uncertainty in the spatial extent and total carbon stocks of these ecosystems. Here, we use a multi-sensor (Landsat, ALOS PALSAR and SRTM) remote sensing approach, together with field data including 24 forest census plots and 218 peat thickness measurements, to map the distribution of peatland vegetation types and calculate the combined above- and below-ground carbon stock of peatland ecosystems in the Pastaza-Marañon foreland basin in Peru. We find that peatlands cover 35 600 ± 2133 km2 and contain 3.14 (0.44-8.15) Pg C. Variation in peat thickness and bulk density are the most important sources of uncertainty in these values. One particular ecosystem type, peatland pole forest, is found to be the most carbon-dense ecosystem yet identified in Amazonia (1391 ± 710 Mg C ha-1). The novel approach of combining optical and radar remote sensing with above- and below-ground carbon inventories is recommended for developing regional carbon estimates for tropical peatlands globally. Finally, we suggest that Amazonian peatlands should be a priority for research and conservation before the developing regional infrastructure causes an acceleration in the exploitation and degradation of these ecosystems.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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. PMID:19669830

  7. 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.

  8. Global warming and climate change in Amazonia: Climate-vegetation feedback and impacts on water resources

    NASA Astrophysics Data System (ADS)

    Marengo, José; Nobre, Carlos A.; Betts, Richard A.; Cox, Peter M.; Sampaio, Gilvan; Salazar, Luis

    This chapter constitutes an updated review of long-term climate variability and change in the Amazon region, based on observational data spanning more than 50 years of records and on climate-change modeling studies. We start with the early experiments on Amazon deforestation in the late 1970s, and the evolution of these experiments to the latest studies on greenhouse gases emission scenarios and land use changes until the end of the twenty-first century. The "Amazon dieback" simulated by the HadCM3 model occurs after a "tipping point" of CO2 concentration and warming. Experiments on Amazon deforestation and change of climate suggest that once a critical deforestation threshold (or tipping point) of 40-50% forest loss is reached in eastern Amazonia, climate would change in a way which is dangerous for the remaining forest. This may favor a collapse of the tropical forest, with a substitution of the forest by savanna-type vegetation. The concept of "dangerous climate change," as a climate change, which induces positive feedback, which accelerate the change, is strongly linked to the occurrence of tipping points, and it can be explained as the presence of feedback between climate change and the carbon cycle, particularly involving a weakening of the current terrestrial carbon sink and a possible reversal from a sink (as in present climate) to a source by the year 2050. We must, therefore, currently consider the drying simulated by the Hadley Centre model(s) as having a finite probability under global warming, with a potentially enormous impact, but with some degree of uncertainty.

  9. Polyspecific associations between squirrel monkeys (Saimiri sciureus) and other primates in eastern Amazonia.

    PubMed

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

    2011-11-01

    One of the most common types of polyspecific association observed in Neotropical primate communities is that between squirrel monkeys (Saimiri) and capuchins (Cebus). The present study focused on association patterns in two Saimiri sciureus groups in eastern Brazilian Amazonia, between March and October, 2009. The associations were analyzed in terms of the species involved, the degree of association, and niche breadth and overlap. The study involved two S. sciureus groups (B4 and GI) on the right and left bank of the Tocantins River, respectively, within the area of the Tucuruí reservoir in southeastern Pará. Relations between species were classified as associations (individuals within 50 m and moving in the same direction), and encounters (individuals within 50 m and no coordinated movement). Group B4 was in association with Cebus apella during 100% of monitoring, and with Chiropotes satanas in 20.2%. By contrast, Group GI associated with Cebus 54.8% of the time, and with Chiropotes utahickae 2.5%. Encounters with Alouatta belzebul and Saguinus niger were recorded at both sites, with Aotus azarae and Dasyprocta prymnolopha at B4, and with Callicebus moloch, Dasyproct aleporina, Mazama gouazoubira, and Nasua nasua at GI. Overall, Saimiri had a broader niche than Cebus in terms of vertical spacing and diet, but not for substrate use. This pattern did not appear to be affected by association. While group GI spent significantly (P < 0.05) more time in association with Cebus during the wet season, group B4 associated with Chiropotes more during the dry season. Despite the higher association rates, niche overlap was greater for all variables at B4. This may reflect differences in the ranging and foraging patterns at the two sites, and the varying potential benefits of association for Saimiri. PMID:21809365

  10. 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.

  11. 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. PMID:25147930

  12. 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.

  13. 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.

  14. Characterization of HBeAg-negative chronic hepatitis B in western Brazilian Amazonia.

    PubMed

    Victoria, Flamir da Silva; Oliveira, Cintia Mara Costa de; Victoria, Marilu Barbieri; Victoria, Cristian Barbieri; Ferreira, Luis Carlos Lima

    2008-02-01

    The present study was conducted with 55 patients native from western Brazilian Amazonia, who were HBV-DNA positive after seroconversion of HBeAg. It is a descriptive case study, with the patients separated into two groups: with hepatitis and without hepatitis on histological examination. The aim of the present study was to describe the clinical and molecular characteristics of patients who are chronic carriers of HBsAg. The prevalence of hepatitis was 63.64%, with a predominance of males (41.82%) and a mean age of 42.5 years, occurring mostly in natives of the southeast sub-region (32.73%). Time was a variable proportional to the course of the disease and the most frequent symptoms were: dyspepsia, asthenia and loss of libido with the majority of the patients having history of prior contact with HBV or positive family history. Splenomegalia was the most frequent sign (40%). Among the tests, platelet count, serum albumin and prothrombin activity were significant in the diagnosis of hepatitis. Alpha-fetoprotein was greater in patients with hepatitis, and hepatocellular carcinoma was detected in 3.63% of the patients with hepatic cirrhosis. Three types of HBV genotypes were diagnosed: A, D and F in the samples amplified for gene S. Genotype A (AA) was observed in 54.54% of the cases with hepatitis, in contrast to other studies showing the predominance of genotype F in this region. We observed mutations in 36.36%, with a predominance of the mutations in the core promoter region (31.81%), due to the greater prevalence of genotype A in this study. PMID:18553011

  15. Sources and sinks of trace gases in Amazonia and the Cerrado

    NASA Astrophysics Data System (ADS)

    Bustamante, M. M. C.; Keller, M.; Silva, D. A.

    Data for trace gas fluxes (NOx, N2O, and CH4) from the Amazon and cerrado region are presented with focus on the processes of production and consumption of these trace gases in soils and how they may be changed because of land use changes in both regions. Fluxes are controlled by seasonality, soil moisture, soil texture, topography, and fine-root dynamics. Compared to Amazonian forests where the rapid cycling of nitrogen supports large emissions of N2O, nitrification rates and soil emissions of N oxide gases in the cerrado region are very low. Several studies report CH4 consumption during both wet and dry seasons in forest soils, but there is occasionally net production of CH4 during the wet season. A few studies suggest an unknown source of CH4 from upland forests. As with N oxide emissions, there are few data on CH4 emissions from cerrado soils, but CH4 consumption occurs during both wet and dry seasons. Clearing natural vegetation, burning, fertilization of agricultural lands, intensive cattle ranching, and increasing dominance by legume species in areas under secondary succession after land conversion have all been identified as causes of increasing N2O and NO emissions from tropical regions. Large uncertainties remain for regional estimates of trace gas fluxes. Improvement of models for the N oxides and CH4 fluxes for Amazonia and the cerrado still depends upon gathering more data from sites more widely distributed across two vast biomes and more importantly on basic theory about the controls of emissions from the ecosystem to the atmosphere.

  16. Pasture burning in Amazonia: Dynamics of residual biomass and the storage and release of aboveground carbon

    NASA Astrophysics Data System (ADS)

    Barbosa, Reinaldo Imbrózio; Fearnside, Philip M.

    1996-11-01

    Aboveground biomass in cattle pasture converted from tropical dense forest was studied both before and after reburning in Brazilian Amazonia. In a 7-year-old pasture studied in Apiaú, Roraima, the aboveground dry weight of biomass (live plus dead) exposed to burning consisted of 96.3 t ha-1 of original forest remains, 6.2 t ha-1 of secondary successional vegetation (woody invaders in the pasture), and 8.0 t ha-1 of pasture grass (carbon contents 48.2%, 45.4%, and 42.2%, respectively). In terms of carbon, burning efficiencies for these three categories were 13.2%, 66.7% and 94.6%, respectively. Net charcoal formation was 0.35 t C ha-1 or 0.63% of the carbon exposed to the reburn, while the total accumulated since conversion (including the initial burn) is estimated at 2.3 t ha-1 (1.82% of the predeforestation aboveground biomass carbon stock). The dynamics of the original forest remains were represented in simulations that included parameters such as charcoal formation, burning efficiency and carbon concentration in different biomass components. Releases from initial burning of the cleared forest (44.0 t C ha-1) plus releases over the course of the succeeding decade through combustion (12.5 t C ha-1) and decay (51.5 t C ha-1) total 92% of the original forest biomass carbon (126 t C ha-1). Of biomass carbon remaining after the initial burn (84.3 t C ha-1), 76.0% is released: 61.1% through decay and 14.9% through combustion in reburns, while 1.2% is net conversion to charcoal in the reburns. These results indicate an amount of charcoal accumulation that is smaller than some carbon calculations have assumed, therefore suggesting a greater impact on global warming from conversion of forest to pasture.

  17. 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.

  18. Trends in streamflow and rainfall in tropical South America: Amazonia, eastern Brazil, and northwestern Peru

    NASA Astrophysics Data System (ADS)

    Marengo, José A.; Tomasella, Javier; Uvo, Cintia R.

    1998-01-01

    Long hydrological records, from the Amazon Basin, northeastern Brazil, and northwestern Peru spanning most of this century, are examined for trends in rainfall (three wettest months) and runoff (three months of highest flow) or stage, where no rating curves exist. Trends are tested for significance using the Mann-Kendall statistic. In basins where large soil, aquifer, or man-made reservoirs give rise to appreciable over-year storage, flows and water levels may be serially correlated. Where serial correlation exists, the usual statistical tests (linear regression, t-test, and Mann-Kendall) will overestimate the significance of trends, showing significance where none exists. Analysis for trend therefore requires particular care when data are serially correlated, and to avoid misleading results, additional supportive evidence must be sought. For example, rainfall records within the same river basin can be checked for trends; serial correlation in rainfall records, in particular, is less likely to be present, so the validity of any trends in rainfall is less open to question. Strong negative trends were found in flow data from the coast of northern Peru and the São Francisco River, while positive significant trends were detected in the Parnaíba River basin. No significant trends were found in the discharge or stage records from Amazonia, while rainfall in northeastern Brazil shows a slow increase over long periods. In the Parnaíba and in some rivers of northern Peru unusually large discharges at the beginning or end of the records seem to account for the direction and significance of trends.

  19. Environmental impacts of Brazil's Tucuruí Dam: unlearned lessons for hydroelectric development in Amazonia.

    PubMed

    Fearnside, P M

    2001-03-01

    Brazil's Tucuruí Dam provides valuable lessons for improving decision-making on major public works in Amazonia and elsewhere. Together with social impacts, which were reviewed in a companion paper, the project's environmental costs are substantial. Monetary costs include costs of construction and maintenance and opportunity costs of natural resources (such as timber) and of the money invested by the Brazilian government. Environmental costs include forest loss, leading to both loss of natural ecosystems and to greenhouse gas emissions. Aquatic ecosystems are heavily affected by the blockage of fish migration and by creation of anoxic environments. Decay of vegetation left in the reservoir creates anoxic water that can corrode turbines, as well as producing methane and providing conditions for methylation of mercury. Defoliants were considered for removing forest in the submergence area but plans were aborted amid a public controversy. Another controversy surrounded impacts of defoliants used to prevent regrowth along the transmission line. Mitigation measures included archaeological and faunal salvage and creation of a "gene bank" on an island in the reservoir. Decision-making in the case of Tucuruí was virtually uninfluenced by environmental studies, which were done concurrently with construction. The dam predates Brazil's 1986 requirement of an Environmental Impact Assessment. Despite limitations, research results provide valuable information for future dams. Extensive public-relations use of the research effort and of mitigation measures such as faunal salvage were evident. Decision-making was closely linked to the influence of construction firms, the military, and foreign financial interests in both the construction project and the use of the resulting electrical power (most of which is used for aluminum smelting). Social and environmental costs received virtually no consideration when decisions were made, an outcome facilitated by a curtain of secrecy

  20. Regional CO2 fluxes for eastern Amazonia derived from aircraft vertical profiles

    NASA Astrophysics Data System (ADS)

    Gatti, L. V.; Miller, J. B.; D'Amelio, M. T.; Wofsy, S.; Tans, P.

    2008-12-01

    We have determined regional scale (~105 - 106 km2) CO2 fluxes using atmospheric measurements from aircraft vertical profiles over eastern Amazonia (site SAN: 02°51'S; 54°57'W). Profiles started December 2000 and have continued through 2008. 17 air samples per profile were collected aboard light aircraft between the surface and 4-5 km using the NOAA/ESRL semi- automatic portable flask package. We use a column integration technique to determine the CO2 flux for each vertical profile, where the measured CO2 profile is differenced from a CO2 background, which was determined using co-measured SF6 as a transport tracer. Two NOAA/ESRL background sites, Ascension Island (ASC) located in the Atlantic Ocean (8°S, 14°W) and Barbados (RPB) located in the Atlantic Ocean (12°N, 59°W) were used to calculate the fractions of air arriving at the sites studied. Back trajectories from the HYSPLIT model were calculated for every profile every 500m of altitude to determine the time the air mass took to travel between the coast and SAN. The observed flux, which is representative of that between the coast and measurement sites, averaged -0.03 ± 1.5 g C m-2day-1 for the wet season and 0.3 ± 0.9 g C m-2day-1 for the dry season. The flux variability is high, probably reflecting the dynamic nature of the response of the terrestrial biosphere to environmental conditions. We have attempted to remove the influence of biomass burning from the fluxes using measurements of co-measured CO. This reduces the dry season flux to -0.04 ± 1.2 g C m- 2day-1. We will compare these results to the seasonality found in eddy covariance measurements and to that estimated from models of the terrestrial biosphere.

  1. Rainfall and surface kinematic conditions over central Amazonia during ABLE 2B

    SciTech Connect

    Greco, S.; Swap, R.; Garstang, M.; Ulanski, S.; Shipham, M. ); Harriss, R.C.; Talbot, R. ); Andreae, M.O. ); Artaxo, P. )

    1990-09-20

    Meteorological and chemical data collected during the wet season Amazon Boundary Layer Experiment near Manaus, Brazil, are used to investigate the rainfall, rainfall systems,and surface kinematics of the central Amazon basin wet season. Analysis of the Geostationary Operational Environmental Satellite (GOES-West) imagery indicates that, based on location of initial development, there are three main types of convective systems which influence a mesoscale network near Manaus. Coastal Occurring Systems (COS) are mesoscale to synoptic scale sized systems of generally linear orientation which form along the northern coast of Brazil and propagate across the Amazon basin. The Basin Occurring Systems (BOS) form in the basin east and north of Manaus and also propagate toward the network. Locally Occurring Systems (LOS) form in and around the mesoscale network and rarely are larger than 1,000 km{sup 2}. Composites of hourly rainfall totals and satellite-derived cloud cover show that rainfall and cloudiness associated with COS occurred in the network between 1,400 and 1,800 UT, while BOS rainfall was most common between 1,000 and 1,400 UT. Little rain or cloud cover was seen before 1,600 UT during days influenced by LOS. Chemical analysis of the rainwater delivered by these systems also shows significant differences in the concentrations of formate, acetate, pyruvate, sulfate, and hydrogen ion. In addition, aerosol concentrations measured near Manaus indicate large influxes of aerosols (sodium, chlorine, and silicon) into central Amazonia after the passage of BOS and COS. During April 11-20, BOS occurred on 8 days and produced 98% of the rainfall. Eight COS occurred during April 21 to May 3 and accounted for 89% of the rainfall. The final part of the experiment, May 4-14, was influenced solely by LOS.

  2. Tucunarella n. Gen. and other dactylogyrids (Monogenoidea) from cichlid fish (Perciformes) from Peruvian Amazonia.

    PubMed

    Mendoza-Franco, Edgar F; Scholz, T; Rozkosná, P

    2010-06-01

    During parasitological research on cichlid fish from the tributaries of the Amazon River around Iquitos, Peru, the following gill monogenoidean species were found: Tucunarella cichlae n. gen. and n. sp. from Cichla monoculus Spix and Agassiz; Gussevia alioides Kritsky, Thatcher, and Boeger, 1986 from Heros severus Heckel; Gussevia asota Kritsky, Thatcher, and Boeger, 1989 from Astronotus ocellatus (Agassiz); Gussevia disparoides Kritsky, Thatcher, and Boeger, 1986 from H. severus (all new geographical records) and Cichlasoma amazonarum Kullander (new host record); Gussevia longihaptor (Mizelle and Kritsky, 1969) Kritsky, Thatcher, and Boeger, 1986 and Gussevia undulata Kritsky, Thatcher, and Boeger, 1986 from C. monoculus ; Sciadicleithrum satanopercae Yamada, Takemoto, Bellay, and Pavanelli, 2008 from Satanoperca jurupari Heckel; and Sciadicleithrum variabilum (Mizelle and Kritsky, 1969) Kritsky, Thatcher, and Boeger, 1989 from C. amazonarum (new host and geographical records). Tucunarella n. gen. is proposed to accommodate a new species, Tucunarella cichlae , which is its type and only known species in the genus. The new genus is characterized by, besides a very large body size (about 1.5 mm vs. much less than 1 mm in other ancyrocephaline genera in Amazonia), a thickened tegument, 1 pair of eyes, overlapping gonads (testis dorsal to the germarium), nonarticulated male copulatory organ (MCO) and accessory piece, a coiled (counterclockwise) MCO, a dextral vaginal aperture, a haptor armed with 2 pairs of anchors (each with broad base and subequal roots, which are marginally folded), and dorsal and ventral bars and 14 hooks with protruding blunt thumbs and 2 different shapes (slender vs. slightly expanded shanks). Illustrations and data on morphological and biometric variability of individual species from different hosts are provided. The present data provide evidence of a relatively wide host specificity of gill monogenoideans parasitic in South American cichlids

  3. 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. PMID:25653668

  4. Diurnal Variation of CO2 concentration above a tropical reservoir in the central Amazonia

    NASA Astrophysics Data System (ADS)

    do Vale, R. S.; Santana, R. A. S. D.; Tota, J.; Souza, R. A. F. D.; Miller, S. D.

    2014-12-01

    The tropical reservoirs of hydroeletric plants have an important role in greenhouse gas emissions into the atmosphere. Due to the large extension of the reservoirs, the lake breeze or land breeze can influence the transport and dispersion of gases. The Balbina reservoir (59° 28' 50'' W, 1° 53' 25''; S), located near Manaus-AM in central Amazonia, is the second biggest hydroeletric plant resevoir in the Amazon basin and has a flooded area of 1770 km2 with an average depth of 10 m, which is enough to produce a dynamic land-lake breeze. In this reservoir, we measured wind direction and velocity from a meteorological buoy and carbon dioxide (CO2) concentrations at 2 m above the lake surface with a high frequency sensor, from 18th to 19th July/2013. The CO2 concentrations were measured at 10 Hz and data were averaged every 5 min during 32 hours. The lake breeze and land breeze from the forest around the lake showed a well-defined behavior, the lake breeze being predominantly from south (S) and the land breeze predominantly from north (N). The CO2 concentration averages were 392 and 426 ppm for daytime and nighttime, respectively. During daytime the atmosphere above the lake was well mixed due to unstable stratification and moderately strong wind speeds. The accumulation of CO2 concentration above the lake at night may have been affected by low wind speeds and enhanced CO2 flux from the water surface due to buoyancy-induced turbulence and physical processes that brought high-CO2 water to the surface. Advection of CO2 from the adjacent forest (land breeze) was also possible.

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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…

  11. 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.

  12. Comparisons of the Noah-MP land surface model simulations with measurements of forest and crop sites in Amazonia

    NASA Astrophysics Data System (ADS)

    Pilotto, Isabel L.; Rodríguez, Daniel A.; Tomasella, Javier; Sampaio, Gilvan; Chou, Sin Chan

    2015-12-01

    This study evaluates the simulations of the Noah-MP surface processes over a crop and a forest sites in Amazonia using tower observations. Soil moisture simulations agree with the observations in both land covers, mainly during the rainy season. However, simulations show cold biases in the soil temperature at both sites. The magnitude and seasonal cycle of the surface energy fluxes are better simulated at the crop site, although the model significantly underestimates the sensible heat flux at this site. The model reproduces the seasonal pattern of surface runoff at both sites. The Noah-MP model does not adequately simulate the base flow at the crop site, while the simulated total runoff at the forest site is closer to the observation than at the crop site. The results show that, in general, the Noah-MP model simulations for the two sites in Amazonia exhibit fairly realistic performance, particularly over the crop site. However, there are cold biases in soil temperature simulations, which could be related with the parameterization of the equilibrium relationship between soil moisture and soil temperature.

  13. 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. PMID:26648541

  14. 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

    NASA Astrophysics Data System (ADS)

    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.

  15. 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

  16. 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

  17. Hair mercury (signature of fish consumption) and cardiovascular risk in Munduruku and Kayabi Indians of Amazonia.

    PubMed

    Dórea, José G; de Souza, Jurandir R; Rodrigues, Patricia; Ferrari, Iris; Barbosa, Antonio C

    2005-02-01

    Fish is an important natural resource in the diet of inhabitants of the Amazon rain forest and a marker of its consumption (hair Hg) was used to compare selected cardiovascular risk parameters between tribes of Eastern Amazonia. Three Munduruku (Terra Preta, Kaburua, Cururu) villages and one Kayabi village at the banks of head rivers (Tapajos, Tropas, Kabitutu, Cururu, Curuzinho, Teles Pires) of the Tapajos Basin were studied in relation to fish Hg concentrations, mercury in hair (fish consumption) and erythrocytes, body mass index (height/weight, kg/cm2), and blood pressure. The mean fish Hg concentrations were higher in predatory (578.6 ng/g) than in nonpredatory species (52.8 ng/g). Overall only 26% of fish Hg concentrations were above 500 ng/g, and only 11% were above 1000 ng/g. There was no systematic trend in fish Hg concentrations from rivers with a history of gold-mining activities. The biomarker of fish consumption (hair Hg) was significantly associated with erythrocyte-Hg (r=0.5181; P=0.0001) and was significantly higher in Kayabi (12.7 microg/g) than in the Munduruku (3.4 microg/g). Biomarker-assessed fish consumption rate was higher in the Kayabi (110 g/day) than in the Munduruku villages (30 g/day). Although no significant differences in body mass index (BMI) were observed between tribes, there was a trend of lower increase in blood pressure with age among the higher fish consumers (Kayabi). Summary clinical evaluation did not detect neurologic complaints compatible with Hg intoxication (paraparesis, numbness, tremor, balancing failure), but endemic tropical diseases such as clinical history of malaria showed a high prevalence (55.4%). Fish is an abundant natural resource, important in the Indian diet, that has been historically consumed without perceived problems and can easily be traced through hair Hg. The exposure to freshwater fish monomethyl mercury is less of an issue than endemic infectious diseases such as malaria and lack of basic medical

  18. Land use change and biogeochemical controls of nitrogen oxide emissions from soils in eastern Amazonia

    NASA Astrophysics Data System (ADS)

    Verchot, Louis V.; Davidson, Eric A.; Catta‸nio, J. Henrique; Ackerman, Ilse L.; Erickson, Heather E.; Keller, Michael

    1999-03-01

    The objectives of this study were (1) to determine the effects of land use change on N oxide fluxes from soil in seasonally dry, eastern Amazonia and (2) evaluate the "hole-in-the-pipe" model in a field setting where N availability varies among land uses and soil moisture varies among seasons. We measured N oxide flux from an old-growth forest, a 20-year-old secondary forest, an active pasture, and a degraded pasture. We also measured soil water content, soil inorganic N stocks, net N mineralization and nitrification potential. To determine the effects of pasture age on N oxide flux, we measured gas fluxes at a chronosequence of pastures (0-13 years). In the land use study, N2O fluxes followed the order: primary forest (2.4 kg N ha-1 yr-1) > secondary forest (0.9 kg N ha-1 yr-1) > active pasture (0.3 kg N ha-1 yr-1) ≥ degraded pasture (0.1 kg N ha-1 yr-1), and NO fluxes followed the order: primary forest (1.5 kg N ha y-11) > degraded pasture (0.7 kg N ha-1 yr-1) > active pasture (0.5 kg N ha-1 yr-1) ≥ secondary forest (0.3 kg N ha-1 yr-1). In the chronosequence study, no trend in N oxide emissions with pasture age was apparent, but emissions from pastures were lower than from the forest.Total N oxide flux correlated with a laboratory measure of nitrification potential (r2 = 0.85).The ratio N2O:NO correlated with soil water content (r2 = 0.56). Parameterization of the model accounted for variability in N oxide emissions across land uses and seasons and the model application revealed the importance of studying both N oxide gases simultaneously. Model predictions for six independent sites agreed well with observed fluxes, suggesting that the model may be applicable at a broader scale. The consistently low annual emissions of N2O estimated for all of the Amazonian pastures that we studied suggest that conversions of tropical forests to cattle pastures may not in the long term cause a significant increase in the contribution of soil emissions to atmospheric N2O or

  19. Modeling Fire Emissions from Multiple Land Use Transitions in Southern Amazonia

    NASA Astrophysics Data System (ADS)

    Morton, D. C.; van der Werf, G. R.; Defries, R. S.; Giglio, L.; Randerson, J. T.; Collatz, G. J.; Kasibhatla, P. S.

    2008-12-01

    Fires for deforestation and other land cover changes in southern Amazonia are an uncertain but significant source of carbon emissions to the atmosphere. Recent expansion of mechanized cropland in the region has increased the rates, clearing sizes, and combustion completeness of forest and Cerrado conversion compared to previous deforestation for cattle ranching. To more accurately quantify the influence of agricultural intensification on carbon emissions, we developed a high-resolution (250 m) model of DEforestation CArbon Fluxes (DECAF). DECAF estimates variations in forest and Cerrado biomass based on time series of MODIS NDVI and explicitly tracks the duration and combustion completeness of new deforestation as a function of post-clearing vegetation phenology and MODIS-based fire frequency. In our model runs for the Brazilian state of Mato Grosso, we quantified the contribution of fires for deforestation, conversion of pasture and Cerrado to mechanized cropland, and pasture maintenance to total fire emissions under low, middle, and high emissions scenarios. During 2001-2005, carbon losses from all types of deforestation were 48-82 Tg per year (mean = 67 Tg C), representing approximately 74% of annual fire emissions in the study region. Cropland expansion in non-forest areas contributed 19% of estimated fire emissions, while maintenance fires in pasture and Cerrado land cover types averaged 7% of all fire emissions during 2001-2005. Conversion of forest to other land uses often takes more than one year, and part of the biomass that was not burned in the dry season following deforestation burned in consecutive years. This led to a partial decoupling of annual deforestation rates and fire emissions, and lowered interannual variability in fire emissions. In total, DECAF-based emissions for Mato Grosso represent 1/3 of estimated fire emissions for all of southern hemisphere South America during this period. Our results demonstrate how DECAF can be used to model

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

    2016-06-01

    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. PMID:27276665

  6. 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

    2016-06-01

    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. PMID:27334826

  7. Mapping hydrological environments in central Amazonia: ground validation and surface model based on SRTM DEM data corrected for deforestation

    NASA Astrophysics Data System (ADS)

    Moulatlet, G. M.; Rennó, C. D.; Costa, F. R. C.; Emilio, T.; Schietti, J.

    2015-03-01

    One of the most important freely available digital elevation models (DEMs) for Amazonia is the one obtained by the Shuttle Radar Topography Mission (SRTM). However, since SRTM tends to represent the vegetation surface instead of the ground surface, the broad use of SRTM DEM as a framework for terrain description in Amazonia is hampered by the presence of deforested areas. We present here two data sets: (1) a deforestation-corrected SRTM DEM for the interfluve between the Purus and Madeira rivers, in central Amazonia, which passed through a careful identification of different environments and has deforestation features corrected by a new method of increasing pixel values of the DEM (Rennó, 2009); and (2) a set of 18 hydrological-topographic descriptors based on the corrected SRTM DEM. Deforestation features are related with the opening of an 800 km road in the central part of the interfluve and occupancy of its vicinity. We used topographic profiles from the pristine forest to the deforested feature to evaluate the recovery of the original canopy coverage by minimizing canopy height variation (corrections ranged from 1 to 38 m). The hydrological-topographic description was obtained by the Height Above the Nearest Drainage (HAND) algorithm, which normalizes the terrain elevation (above sea level) by the elevation of the nearest hydrologically connected drainage. The validation of the HAND data set was done by in situ hydrological description of 110 km of walking trails also available in this data set. The new SRTM DEM expands the applicability of SRTM data for landscape modelling; the data sets of hydrological features based on topographic modelling are undoubtedly appropriate for ecological modelling and an important contribution to environmental mapping of Amazonia. The deforestation-corrected SRTM DEM is available at http://ppbio.inpa.gov.br/knb/metacat/naman.318.3/ppbio; the

  8. Groundwater as a Source of Evapotranspiration in the Dry Season in Amazonia: Simulations with the LEAFHYDRO LSM

    NASA Astrophysics Data System (ADS)

    Miguez-Macho, G.; Fan, Y.

    2010-12-01

    Land-surface models simulate vegetation stress in the dry season in the Amazon due to the reduced precipitation, but observations show enhanced growth in response to higher radiation, indication of an adequate water supply. The question is: how does the vegetation obtain sufficient water, and what is missing in the models? Shallow model soil and rooting depth is a factor; the ability of roots to move water up and down (hydraulic redistribution) may be another, but another cause may lie in the buffering effect of the groundwater found in nature but absent in models. The upward capillary water flux from a shallow water table can meet a significant portion of the atmospheric potential evapotranpiration demand. Here we assess the impact of the shallow water table over Amazonia, raised by high infiltration and poor drainage, as a source of water for evapotranspiration in the dry season. We perform simulations with the LEAFHYDRO land-surface model, including water table dynamics, at 1 arc-minute horizontal resolution over the Amazon ecosystem region for several years using SALDAS (South America Land Data Assimilation) atmospheric forcing. Two sets of simulations are compared, one with groundwater and one without, letting excess infiltration drain at the bottom of soil columns. Results show that over the extensive areas with shallow water tables, little or no reduction in ET is simulated in the dry season when groundwater is considered in the model, indication of the prominent role of the vast groundwater store over Amazonia for the climate and ecology of the region and the need to consider it in climate model simulations.

  9. [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

  10. Seasonal patterns of rainfall and river isotopic chemistry in northern Amazonia (Guyana): From the headwater to the regional scale

    NASA Astrophysics Data System (ADS)

    Pereira, Ryan; Bovolo, C. Isabella; Forsythe, Nathan; Pedentchouk, Nikolai; Parkin, Geoff; Wagner, Thomas

    2014-07-01

    We use first field-based observations of precipitation and river isotopic chemistry from a three-year study (2009-2011) in rainforest and nearby savannah in central Guyana at the northern rim of the Amazon rainforest to establish the quality of modelled or remotely-sensed datasets. Our 3 years of data capture a reduced rainfall regime in 2009 and an extended wet season in 2010, in contrast to the widely documented Amazonian floods in 2009 and droughts in 2010. Comparisons of observed precipitation with satellite derived TRMM and ECMWF ERA-Interim reanalysis precipitation show that both of these data sets capture the general pattern of seasonality, but substantially underestimate rainfall amounts in the primary wet season (by up to 50% and 72% respectively). The TRMM dataset is generally better at characterising the main dry season from September to December but the ERA-Interim model can overestimate precipitation in the dry season by up to 175%. Our new data on isotopic chemistry of river waters show that δ2H/δ18O values in this region are broadly consistent with interpolated global datasets of modelled precipitation isotopic signatures. The dominance of isotopically lighter water derived from the rains of the ITCZ during the wet season provides evidence of the close coupling of water chemistry of headwater rivers on the northern rim of Amazonia to the positioning of the ITCZ over the region. Our results highlight the challenge in understanding and representing local scale hydrological and biogeochemical characteristics using regional scale model data. We argue that combining point and local scale field data with larger scale model data is necessary to progress towards a comprehensive understanding of climate-hydrology interactions in Amazonia.

  11. 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

  12. Comparative measurements and seasonal variations in energy and carbon exchange over forest and pasture in South West Amazonia

    NASA Astrophysics Data System (ADS)

    von Randow, C.; Manzi, A. O.; Kruijt, B.; de Oliveira, P. J.; Zanchi, F. B.; Silva, R. L.; Hodnett, M. G.; Gash, J. H. C.; Elbers, J. A.; Waterloo, M. J.; Cardoso, F. L.; Kabat, P.

    Comparative measurements of radiation flux components and turbulent fluxes of energy and CO2 are made at two sites in South West Amazonia: one in a tropical forest reserve and one in a pasture. The data were collected from February 1999 to September 2002, as part of the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA). During the dry seasons, although precipitation and specific humidity are greatly reduced, the soil moisture storage profiles down to 3.4m indicate that the forest vegetation continues to withdraw water from deep layers in the soil. For this reason, seasonal changes observed in the energy partition and CO2 fluxes in the forest are small, compared to the large reductions in evaporation and photosynthesis observed in the pasture. For the radiation balance, the reflected short wave radiation increases by about 55% when changing from forest to pasture. Combined with an increase of 4.7% in long wave radiation loss, this causes an average reduction of 13.3% in net radiation in the pasture, compared to the forest. In the wet season, the evaporative fraction (λE/Rn) at the pasture is 17% lower than at the forest. This difference increases to 24% during the dry season. Daytime CO2 fluxes are 20-28% lower (in absolute values) in the pasture compared to the forest. The night-time respiration in the pasture is also reduced compared to the forest, with averages 44% and 57% lower in the wet and dry seasons, respectively. As the reduction in the nocturnal respiration is larger than the reduction in the daytime uptake, the combined effect is a 19-67% higher daily uptake of CO2 in the pasture, compared to the forest. This high uptake of CO2 in the pasture site is not surprising, since the growth of the vegetation is constantly renewed, as the cattle remove the biomass.

  13. 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.

  14. 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

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

    NASA Astrophysics Data System (ADS)

    Alves, E. G.; Jardine, K.; Tota, J.; Jardine, A.; Yáñez-Serrano, A. M.; Karl, T.; Tavares, J.; Nelson, B.; Gu, D.; Stavrakou, T.; Martin, S.; Manzi, A.; Guenther, A.

    2015-10-01

    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, profiles were collected of the vertical profile of mixing ratios of isoprene, total monoterpenes and total sesquiterpenes, 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 to 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

  16. Evolution of a Quaternary paleoria (Southwest Amazonia) and its impact on the distribution of modern vegetation

    NASA Astrophysics Data System (ADS)

    Bertani, T. C.; Rossetti, D.; Hayakawa, E. H.

    2012-12-01

    Fluvial rias and patches of open vegetation in sharp contrast with dense tropical forest are among the most remarkable features in many areas of the Amazonian lowlands. These features occupy large areas and often display similar geometry and dimensions, especially when located nearby main river courses. The fluvial rias in the Amazonas basin have been described as lakes formed by the impoundment of tributary rivers in their lower courses due to increased aggradation. The origin of this kind of lake has been related to post-glacial eustatic variations, although neotectonic influence has also been considered an important control of the contemporary conformation observed for these Amazonian lakes. Groups of fluvial rias do follow the basin's superimposed axis, and are not randomly located, as opposed to erosive lakes within the floodplains. In addition, open vegetation patches within the Amazonas basin have been, in general, related to Pleistocene climatic oscillations or edaphic variations resulting from geological and geomorphological processes. However, a few of these patches have geometry and dimensions conforming to many modern fluvial rias of the Amazonian region, leading to hypothesize an origin potentially related to this landform. Studies integrating geological and remote sensing data for different Amazonian areas have suggested changes in fluvial sedimentary dynamics during the late Quaternary as the key for the establishment of many patches of open vegetation. Morphostructural evidence also has been used to relate frequent changes in the river systems to fault reactivations. The purpose of this work is to present the results of an interdisciplinary investigation including remote sensing, sedimentology, radiocarbon chronology δ13C, δ15N, and C/N from a landform related to the infill of a paleoria of the Madeira River in southwestern Amazonia. The results of this investigation revealed a sedimentary succession displaying ages between 21,547 - 22,285 cal

  17. 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

  18. 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.

  19. Cloud characteristics over central Amazonia during GTE/ABLE 2B derived from multispectral visible and infrared spin scan radiometer atmospheric sounder observations

    SciTech Connect

    Menzel, W.P. ); Schmit, T.J.; Wylie, D.P. )

    1990-09-20

    Multispectral GOES/Visible and Infrared Spin Scan Radiometer Atmospheric Sounder (VAS) observations in the carbon dioxide absorption band at 15 {mu}m have been used to calculate diurnal cloud statistics over central Amazonia region for 4 days during the Global Tropospheric Experiment/Amazon Boundary Layer Experiment (GTE/ABLE IIB). The CO{sub 2} technique calculates both cloud top pressure and effective emissivity from radiative transfer principles. Transmissive clouds that are partially transparent to terrestrial radiation have been reliably separated from opaque clouds in the statistics of cloud cover. A high incidence of transmissive clouds (about 47%) was found on the average. Diurnal characteristics of cloud cover over Amazonia have been linked to convective activity over this region. On days with afternoon convection, an increase in low-altitude opaque clouds was followed by a subsequent increase in high-altitude transmissive clouds.

  20. 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

  1. 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

  2. Primate abundance and habitat preferences on the lower Urubamba and Tambo rivers, central-eastern Peruvian Amazonia.

    PubMed

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

    2013-10-01

    We report information on population density, group size, and habitat preferences of primates along the lower Río Urubamba and in the Río Urubamba-Río Tambo interfluvium, in central-eastern Peruvian Amazonia, an area that has been little explored with regard to its primate fauna. During 425 km of transect walks in October-November 2008 and April-May 2009 totally 174 groups of nine primate species were encountered, the most common being Callicebus brunneus (45 groups), Saguinus imperator (41 groups), and Aotus nigriceps (26 groups). Group sizes were smallest for A. nigriceps and C. brunneus (mean of 2.8 and 2.9, respectively) and largest for Saimiri boliviensis (mean 15.6). Population densities were lowest for Lagothrix cana (3.3 individuals/km(2)) and highest for A. nigriceps (31.1 individuals/km(2)). Groups of C. brunneus, S. imperator, S. boliviensis, Cebus albifrons, and Cebus apella were most frequently (83 % of sightings) encountered in semi-dense or in open primary forest that included stands of bamboo (Guadua sarcocarpa) or where bamboo was a very common species. PMID:23661029

  3. Modeling the dynamic root water uptake and its hydrological impact at the Reserva Jaru site in Amazonia

    NASA Astrophysics Data System (ADS)

    Zheng, Zhe; Wang, Guiling

    2007-12-01

    An empirical approach is proposed to represent the impact of dynamic root water uptake by plant roots in two land surface models (Community Land Model version 3 (CLM3) and Integrated Biosphere Simulator version 2 (IBIS2)). This approach is compared with a more physically based approach that simulates the hydraulic redistribution, using the Reserva Jaru site in Amazonia as an example. For each model and each approach, two different root profiles are experimented on, an exponential profile and an observed, deeper profile. In both CLM3 and IBIS2, including dynamic root uptake significantly improves the model simulation of latent heat fluxes, regardless of what root profile is used. In both models, the impact of hydraulic redistribution (as accounted for by the physically based approach) is comparable to that of a low degree of dynamic root water uptake (as accounted for by the empirical approach). The latent heat flux simulation in IBIS2 is closer to observation than is that in CLM3, with or without the impact of dynamic root water uptake. Despite the model improvement due to including dynamic root water uptake, significant biases in soil moisture simulations remain. Assimilating soil moisture observations into the land surface models produces a remarkably improved latent heat flux simulation. Parameterization in surface and subsurface runoff (which influences soil moisture) is suggested as a likely cause for the severe biases in the default model simulations, which highlights the critical importance of correctly simulating the fundamental hydrological processes in land surface models.

  4. 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. PMID:27010739

  5. 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. PMID:23296267

  6. Chemical composition of the fruit mesocarp of three peach palm (Bactris gasipaes) populations grown in central Amazonia, Brazil.

    PubMed

    Yuyama, Lúcia K O; Aguiar, Jaime P L; Yuyama, Kaoru; Clement, Charles R; Macedo, Sonja H M; Fávaro, Deborah I T; Afonso, Claudia; Vasconcellos, Marina B A; Pimentel, Sabria A; Badolato, Elsa S G; Vannucchi, Helio

    2003-01-01

    The percent composition, soluble and insoluble food fibers, oil fatty acids and minerals were determined in the mesocarp of fruits of three peach palm (Bactris gasipaes Kunth) populations grown in Central Amazonia, Brazil. Amino acids were also determined in one of the populations. The mean protein levels ranged from 1.8 to 2.7%, lipid levels ranged from 3.5 to 11.1%, the nitrogen free fraction ranged from 24.3 to 35%, food fiber ranged from 5.2% to 8.7%, and energy ranged from 179.1 to 207.4 kcal%. All essential, as well as non-essential, amino acids were present, with tryptophan and methionine presenting the lowest mean concentrations. The mono-unsaturated oleic acid predominated in the oil, ranging from 42.8 to 60.8%, and palmitic acid was the most abundant saturated fatty acid, ranging from 24.1 to 42.3%. Among the essential fatty acids, linoleic acid was the most abundant, with a maximum of 5.4% in Pampa-8. The most important mineral elements were potassium, selenium and chromium, respectively corresponding to 12%, 9% and 9% of daily recommended allowances. Considering the nutritional potential of the fruit, we suggest its more frequent incorporation into the diet of the Amazonian population. PMID:12701237

  7. 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. PMID:17255028

  8. The Cotingo Dam as a test of Brazil`s system for evaluating proposed developments in Amazonia

    SciTech Connect

    Fearnside, P.M.; Barbosa, R.I.

    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. 39 refs., 4 figs., 1 tab.

  9. Loss of nutrients from terrestrial ecosystems to streams and the atmosphere following land use change in Amazonia

    NASA Astrophysics Data System (ADS)

    Davidson, Eric A.; Neill, Christopher; Krusche, Alex V.; Ballester, Victoria V. R.; Markewitz, Daniel; Figueiredo, Ricardo de O.

    Rates of deforestation in the Amazon region have been accelerating, but the quantity and timing of nutrient losses from forested and deforested ecosystems are poorly understood. This paper investigates the broad variation in soil properties of the Amazon Basin as they influence transfers of plant nutrients from the terrestrial biosphere to the atmosphere and the aquatic biosphere. The dominant lowland soils are highly weathered Oxisols and Ultisols, but significant areas of Alfisols also exist, resulting in a wide range of weatherable primary minerals. Despite this considerable variation among Amazonian soils, a common feature in most mature lowland Amazonian forests is a conservative P cycle and excess N availability. In cattle pastures and secondary forests, however, low rates of internal terrestrial N cycling, low N export to streams, and low gaseous N emissions from soils are common, due to significant previous losses of N through repeated fire. Export of P to streams may increase or remain nearly undetectable after forest-to-pasture conversion, depending on soil type. Oxisols exhibit very low P export, whereas increased P export to pasture streams has been observed in Ultisols of western Amazonia. Calcium is mostly retained in terrestrial ecosystems following deforestation, although increased inputs to streams can be detected when background fluxes are naturally low. Because soil mineralogy and soil texture are both variable and important, the effects of land-use change on nutrient export to aquatic ecosystems and to the atmosphere must be understood within the context of varying soil properties across the Amazon Basin.

  10. Tropical Forest Backscatter Anomaly Evident in SeaWinds Scatterometer Morning Overpass Data During 2005 Drought in Amazonia

    NASA Astrophysics Data System (ADS)

    Frolking, S. E.; Milliman, T.; Palace, M. W.; Wisser, D.; Lammers, R. B.; Fahnestock, M. A.

    2010-12-01

    A severe drought occurred in many portions of Amazonia in the dry season (June-September) of 2005. We analyzed ten years (7/99-10/09) of SeaWinds active microwave Ku-band backscatter data collected over the Amazon Basin, developing a monthly climatology and monthly anomalies from that climatology in an effort to detect landscape responses to this drought. We compared these to seasonal accumulating water deficit anomalies generated using Tropical Rainfall Monitoring Mission (TRMM) precipitation data (1999-2009) and 100 mm/mo evapotranspirative demand as a water deficit threshold. There was significant interannual variability in monthly mean backscatter only for ascending (early morning) overpass data, and little interannual variability in monthly mean backscatter for descending (late afternoon) overpass data. Strong negative anomalies in both ascending-overpass backscatter and accumulating water deficit developed during July-October 2005, centered on the southwestern Amazon Basin (Acre and western Amazonas states in Brazil; Madre de Dios state in Peru; Pando state in Bolivia). During the 2005 drought, there was a strong spatial correlation between morning overpass backscatter anomalies and water deficit anomalies. We hypothesize that as the drought persisted over several months, the forest canopy was increasingly unable to recover full leaf moisture content over night, and the early morning overpass backscatter data became anomalously low. This is the first reporting of tropical wet forest seasonal drought detection by active microwave scatterometry.

  11. The effect of seasonality on the structure of rotifers in a black-water shallow lake in Central Amazonia.

    PubMed

    Nova, Clarice C; Lopes, Vanessa G; Souza, Leonardo Coimbra E; Kozlowsky-Suzuki, Betina; Pereira, Talita A A; Branco, Christina W C

    2014-09-01

    Rotifers have often been used as indicators of sudden changes in physical and chemical features of the aquatic environment. Such features vary greatly during flood pulse events in small lakes connected to major floodplains. However, few are the studies that investigate the consequences of the flood pulse in rotifer species composition, abundance, richness and diversity, especially in Amazonian lakes. We analyzed samples from a small blackwater lake of an "igarapé" connected permanently to the Negro river, in Central Amazonia. Samples were taken twice a year for two years, comprising flooding and receding periods of the flood pulse. Rotifer abundance increased significantly after draught events, and electrical conductivity and turbidity were intrinsically related to such variation. Species composition also changed from flooding to receding periods. Some taxa, such as Brachionus zahniseri reductus and Lecane remanei were restricted to receding periods, while Brachionus zahniseri, Brachionus gillardi and Lecane proiecta were only present during flooding. A shift in the composition of rotifer families was observed from one period to another, showing the effect of renewing waters of the flood pulse. These results suggest that the flood pulse acts as a driving force and stressing condition, considerably altering rotifer community dynamics, either changing species composition or decreasing abundance. PMID:25119730

  12. 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

  13. 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

  14. Rainwater and throughfall chemistry in a terra firme rain forest: Central Amazonia

    SciTech Connect

    Forti, M.C.; Moreira-Nordemann, L.M. )

    1991-04-20

    During the Global Tropospheric Experiment (GTE)-Amazon Boundary Layer Experiment (ABLE) 2B campaign in the Amazon basin, samples of rainwater and throughfall were obtained in a terra firme (nonflooded forest) rain forest at the Ducke Reserve (2{degree}57{prime}S, 59{degree}58{prime}W). The samples were collected during one wet period (April 1 to May 13, 1987) and one dry period (August 1 to October 1, 1987). All samples were analyzed for Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, NH{sub 4}{sup +}, Cl{sup {minus}} and SO{sub 4}{sup 2{minus}}, and pH. The rainwater was acidic, with a volume-weighted mean pH of 4.6 for two periods. Rainwater input from the dry period was 2 times greater for Na{sup +}, Mg{sup 2+}, NH{sub 4}{sup +}and SO{sub 4}{sup 2{minus}} and about 4 times greater for K{sup +} than from the wet period. The ionic concentrations in throughfall were higher than those in rainwater, except for NH{sub 4}{sup +} during the dry period. This enrichment of throughfall is attributed to the interaction of precipitation with the forest canopy.

  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. 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. PMID:24891412

  17. 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. PMID:23546826

  18. 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. PMID:23382890

  19. 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.

  20. Late Quaternary sedimentary dynamics in Western Amazonia: Implications for the origin of open vegetation/forest contrasts

    NASA Astrophysics Data System (ADS)

    Rossetti, D. F.; Bertani, T. C.; Zani, H.; Cremon, E. H.; Hayakawa, E. H.

    2012-12-01

    This work investigated the evolution of sedimentary environments during the latest Quaternary and their influence on the paradoxical occurrence of open vegetation patches in sharp contact with the Amazonian forest. The approach integrated pre-existing geological and floristic data from lowlands in the Brazilian Amazonia, with remote sensing imagery including multispectral optical images (TM, ETM+, and ASTER), Phased Array L-band Synthetic Aperture Radar (PALSAR), InSAR C-band SRTM-DEMs, and high resolution images obtained from Google Earth™. The detection of an abundance of paleomorphologies provided evidence of a scenario in which constant environmental shifts were linked to the evolution of fluvial and megafan depositional systems. In all studied areas, the open vegetation patches are not random, but associated with sedimentary deposits representative of environments either deactivated during the Holocene or presently in the process of deactivation. Sedimentary evolution would have determined the distribution of wetlands and terra firme in many areas of the Amazonian lowlands, and would have a major impact on the development of open vegetated patches within the modern rainforest. Subsiding areas were filled up with megafan deposits, and many fluvial tributaries were rearranged on the landscape. The close relationship between vegetation and the physical environment suggests that sedimentary history related to the evolution of depositional settings during the latest Quaternary played a major role in the distribution of flooded and non-flooded areas of the Amazonian lowlands, with a direct impact on the distribution of modern floristic patterns. As the depositional sites were abandoned and their sedimentary deposits were exposed to the surface, they became sites suitable for vegetation growth, first of herbaceous species and then of forest. Although climate fluctuations might have been involved, fault reactivation appears to have been the main cause of changes in

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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

  7. Biogeochemical Indicators of Paleoenvironmental Changes in a Humid Region of Amazonia (Lagoa da Pata, Sao Gabriel da Cachoeira)

    NASA Astrophysics Data System (ADS)

    Cordeiro, R. C.; Turcq, B.; Mendes, L. G.; Azeredo, J. B.; Moura, M. S.; de Oliveira, A. R.; Monteiro, F.; Santelli, R. E.

    2004-12-01

    Analysis of four sediment core collected in Lagoa da Pata lake show significant changes in the environmental history of Amazonia during the last 40,000 years. The Lagoa da Pata Lake (0°17'S, 66°40'W) is located on the top of the Morro dos Seis Lagos, an isolated hill in the extensive forested plane surface of high Rio Negro basin. The climate in the region presents mean annual precipitation around 3000 mm without dry season. Three distinct sections are clearly identified in the LPT III, LPT IV and LPT V cores. They consist of upper and lower organic-rich layers, separated by a clastic layer which represents a short period of rapid accumulation around 18 ka BP. Analysis of the organic matter composition by d13C and d15N, total Carbon and Nitrogen, sedimentary chlorophyll concentration and organic matter petrography show three different phases related to organic matter deposition. Between, at least 46,000 and 31,000 14C yr B.P., the lake presented a high water level attested by high accumulation rates of organic carbon. Values of d13C (around -32%) associated to high C/N ratio demonstrate a lignocellulosic material contribution in this phase; the second phase between the 31000 yr 14C B.P. and 18000 14C B.P. is characterised by a lower productivity attested by low sedimentary chlorophyll and total organic carbon values. The d13C values increase with medium values around -28% that may correspond to an input of organic matter rich in C4 plants (grasses). The sedimentation rate decreases significantly. High charcoal fluxes were observed in this period. At around 18000 14C yr BP, there appears to have been a sudden input of clastic material. This is represented by a sandy facies, which exhibits lower carbon contents. From 18000 14C yr B.P. to the present time occurred an increase in lacustrine productivity marked by an increase in carbon and chlorophyll derivate accumulation rates. The C/N values dropped indicting an algae organic matter contribution. It probably

  8. 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

  9. 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

  10. 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