Evapotranspiration seasonality across the Amazon Basin

NASA Astrophysics Data System (ADS)

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

2017-06-01

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

Forest-rainfall cascades buffer against drought across the Amazon

NASA Astrophysics Data System (ADS)

Staal, Arie; Tuinenburg, Obbe A.; Bosmans, Joyce H. C.; Holmgren, Milena; van Nes, Egbert H.; Scheffer, Marten; Zemp, Delphine Clara; Dekker, Stefan C.

2018-06-01

Tree transpiration in the Amazon may enhance rainfall for downwind forests. Until now it has been unclear how this cascading effect plays out across the basin. Here, we calculate local forest transpiration and the subsequent trajectories of transpired water through the atmosphere in high spatial and temporal detail. We estimate that one-third of Amazon rainfall originates within its own basin, of which two-thirds has been transpired. Forests in the southern half of the basin contribute most to the stability of other forests in this way, whereas forests in the south-western Amazon are particularly dependent on transpired-water subsidies. These forest-rainfall cascades buffer the effects of drought and reveal a mechanism by which deforestation can compromise the resilience of the Amazon forest system in the face of future climatic extremes.

Hydrologic resilience and Amazon productivity.

PubMed

Ahlström, Anders; Canadell, Josep G; Schurgers, Guy; Wu, Minchao; Berry, Joseph A; Guan, Kaiyu; Jackson, Robert B

2017-08-30

The Amazon rainforest is disproportionately important for global carbon storage and biodiversity. The system couples the atmosphere and land, with moist forest that depends on convection to sustain gross primary productivity and growth. Earth system models that estimate future climate and vegetation show little agreement in Amazon simulations. Here we show that biases in internally generated climate, primarily precipitation, explain most of the uncertainty in Earth system model results; models, empirical data and theory converge when precipitation biases are accounted for. Gross primary productivity, above-ground biomass and tree cover align on a hydrological relationship with a breakpoint at ~2000 mm annual precipitation, where the system transitions between water and radiation limitation of evapotranspiration. The breakpoint appears to be fairly stable in the future, suggesting resilience of the Amazon to climate change. Changes in precipitation and land use are therefore more likely to govern biomass and vegetation structure in Amazonia.Earth system model simulations of future climate in the Amazon show little agreement. Here, the authors show that biases in internally generated climate explain most of this uncertainty and that the balance between water-saturated and water-limited evapotranspiration controls the Amazon resilience to climate change.

An approach to the coastal water circulation in the Piratuba Lake Biological Reservation, Northeast of Amapa State, Brazil

NASA Astrophysics Data System (ADS)

Takiyama, L. R.; Silveira, O. M.

2007-05-01

This study shows the pioneer results of the water quality characterization of a lake region, including the Piratuba lake (within the limits of the Piratuba Lake Biological Reservation) and the Sucuriju river, localized at the northeast portion of the Amapa State, Brazil, and left margin of the Amazon River mouth. Due to the influence of the Amazon river and another important river, the Araguari river, the northeast coast of Amapa State receive little impact of salty water from the Atlantic ocean. The highest salinity values detected on this coastal area is 20 psu. The Piratuba Lake region which can be described as an unique wetland system formed by recent geological processes (Quaternary), it constitutes a very fragile environment and possesses a number of shallow water lakes distributed into a mixed mangrove and "varzea" type of vegetation and it is considered very important looking at the biological point of view. The borderline between this lake system with the coastal waters is a narrow portion of mangrove containing species of Rizhophora and Avicennia parallel to the coast line. A preliminary water circulation could be accessed through the detection of variation in water quality parameters throughout three field studies conducted on March, 2004, June 2005 and November 2005. Surface water sampling points spatially distributed on the study area with distances less than 2 km were set, covering almost 800 square kilometers. Among the parameters studied (pH, electrical conductivity, turbidity, concentration of suspended solids, depth, temperature, chloride, dissolved oxygen, nitrate, nitrite and phosphate) the turbidity, electrical conductivity and pH were the most important for identifying the entering of coastal waters into the lake region. Mainly, three points of direct contact were identified; one of them is a manmade illegal entrance to the Biological Reservation. The seasonal variation was also very important factor and as expected, during the dry season (July to November, represented by the study on November 2006), we could measured the highest values of conductivity, pH and turbidity in many of the lakes sampled. The implications of understanding, even preliminarily the water circulation in the study area is related to the influence onto the freshwater living species, environemtnal conservation management purposes, geomorphology process indicator and the possible biogeochemical exchanges dynamics, once the Amazon waters can be nutrient rich and the lake waters apparently have high dissolved organic carbon content.

Water contamination from oil extraction activities in Northern Peruvian Amazonian rivers.

PubMed

Yusta-García, Raúl; Orta-Martínez, Martí; Mayor, Pedro; González-Crespo, Carlos; Rosell-Melé, Antoni

2017-06-01

Oil extraction activities in the Northern Peruvian Amazon have generated a long-standing socio-environmental conflict between oil companies, governmental authorities and indigenous communities, partly derived from the discharge of produced waters containing high amounts of heavy metals and hydrocarbons. To assess the impact of produced waters discharges we conducted a meta-analysis of 2951 river water and 652 produced water chemical analyses from governmental institutions and oil companies reports, collected in four Amazonian river basins (Marañon, Tigre, Corrientes and Pastaza) and their tributaries. Produced water discharges had much higher concentrations of chloride, barium, cadmium and lead than are typically found in fresh waters, resulting in the widespread contamination of the natural water courses. A significant number of water samples had levels of cadmium, barium, hexavalent chromium and lead that did not meet Peruvian and international water standards. Our study shows that spillage of produced water in Peruvian Amazon rivers placed at risk indigenous population and wildlife during several decades. Furthermore, the impact of such activities in the headwaters of the Amazon extended well beyond the boundaries of oil concessions and national borders, which should be taken into consideration when evaluating large scale anthropogenic impacts in the Amazon. Copyright © 2017 Elsevier Ltd. All rights reserved.

Seasonal dynamics in methane emissions from the Amazon River floodplain to the troposphere

NASA Technical Reports Server (NTRS)

Devol, Allan H.; Richey, Jeffrey E.; Forsberg, Bruce R.; Martinelli, Luiz A.

1990-01-01

Methane fluxes to the troposphere from the three principal habitats of the floodplain of the Amazon River main stem (open waters, emergent macrophyte beds, and flooded forests) were determined along a 1700-km reach of the river during the low-water period of the annual flood cycle (November-December 1988). Overall, emissions averaged 68 mg CH4/sq m per day and were significantly lower than similar emissions determined previously for the high-water period, 184 mg CH4/sq m per day (July-August 1986). This difference was due to significantly lower emissions from floating macrophyte environments. Low-water emissions from open waters and flooded forest areas were not significantly different than at high water. A monthly time series of methane emission from eight lakes located in the central Amazon basis showed similar results. The data were used to calculate a seasonally weighted annual emission to the troposphere from the Amazon River main stem floodplain of 5.1 Tg/yr, which indicates the importance of the area in global atmospheric chemistry.

Isotopic values of the Amazon headwaters in Peru: comparison of the wet upper Río Madre de Dios watershed with the dry Urubamba-Apurimac river system.

PubMed

Lambs, L; Horwath, A; Otto, T; Julien, F; Antoine, P-O

2012-04-15

The Amazon River is a huge network of long tributaries, and little is known about the headwaters. Here we present a study of one wet tropical Amazon forest side, and one dry and cold Atiplano plateau, originating from the same cordillera. The aim is to see how this difference affects the water characteristics. Different kind of water (spring, lake, river, rainfall) were sampled to determine their stable isotopes ratios (oxygen 18/16 and hydrogen 2/1) by continuous flow isotope ratio mass spectrometry (IRMS). These ratios coupled with chemical analysis enabled us to determine the origin of the water, the evaporation process and the water recycling over the Amazon plain forest and montane cloud forest. Our study shows that the water flowing in the upper Madre de Dios basin comes mainly from the foothill humid forest, with a characteristic water recycling process signature, and not from higher glacier melt. On the contrary, the water flowing in the Altiplano Rivers is mainly from glacier melts, with a high evaporation process. This snow and glacier are fed mainly by Atlantic moisture which transits over the large Amazon forest. The Atlantic moisture and its recycling over this huge tropical forest display a progressive isotopic gradient, as a function of distance from the ocean. At the level of the montane cloud forest and on the altiplano, respectively, additional water recycling and evaporation occur, but they are insignificant in the total water discharge. Copyright © 2012 John Wiley & Sons, Ltd.

Geochemistry of the Amazon Estuary

USGS Publications Warehouse

Smoak, Joseph M.; Krest, James M.; Swarzenski, Peter W

2006-01-01

The Amazon River supplies more freshwater to the ocean than any other river in the world. This enormous volume of freshwater forces the estuarine mixing out of the river channel and onto the continental shelf. On the continental shelf, the estuarine mixing occurs in a very dynamic environment unlike that of a typical estuary. The tides, the wind, and the boundary current that sweeps the continental shelf have a pronounced influence on the chemical and biological processes occurring within the estuary. The dynamic environment, along with the enormous supply of water, solutes and particles makes the Amazon estuary unique. This chapter describes the unique features of the Amazon estuary and how these features influence the processes occurring within the estuary. Examined are the supply and cycling of major and minor elements, and the use of naturally occurring radionuclides to trace processes including water movement, scavenging, sediment-water interaction, and sediment accumulation rates. The biogeochemical cycling of carbon, nitrogen, and phosphorus, and the significances of the Amazon estuary in the global mass balance of these elements are examined.

(210)Pb and composition data of near-surface sediments and interstitial waters evidencing anthropogenic inputs in Amazon River mouth, Macapá, Brazil.

PubMed

Nery, José Reinaldo Cardoso; Bonotto, Daniel Marcos

2011-04-01

Activity profiles of excess (210)Pb determined in three sediment cores from Amazon River mouth, Macapá city, Brazil, provided the evaluation of sedimentation rates, contributing to a better knowledge of the hydrological conditions in the site that is the capital of Amapá State and is drained by the waters of the huge Amazon River. Chemical data were also determined in the sediments, allowing identify signatures coupled to anthropogenic inputs held in the past in Amapá State. Significant direct relationships between LOI (loss on ignition) and organic matter were found for all sediments profiles. Silica was found to be inversely related to organic matter in the three profiles; its decrease accompanied an increase on the specific surface of the sediments. This relationship was confirmed by a great number of inverse significant correlations among silica and oxides Na(2)O, K(2)O, CaO, MgO, Al(2)O(3), P(2)O(5), Fe(2)O(3) and MnO. It was possible to identify the role of organic matter on adsorption of several oxides in the core sediments profiles. Apparent sediment mass accumulation rates corresponding to values between 450 and 2510 mg cm(-2)yr(-1) were obtained, and are compatible with the results of others studies. The (210)Pb activities in one sampling point suggested the occurrence of anthropogenic inputs related to the initial period of the mining activities conducted in Serra do Navio, Amapá State, for the commercialization of Mn ores. This was reinforced by the abrupt fluctuations in chemical data obtained for the sediments and composition of the interstitial waters occurring there. The Atlantic hurricane activity also appeared to affect the sedimentation rates in the area, as two different values were recorded in each profile. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

USDA-ARS?s Scientific Manuscript database

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

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

USDA-ARS?s Scientific Manuscript database

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

Multi-model analysis of the Atlantic influence on Southern Amazon rainfall

DOE PAGES

Yoon, Jin -Ho

2015-12-07

Amazon rainfall is subject to year-to-year fluctuation resulting in drought and flood in various intensities. A major climatic driver of the interannual variation of the Amazon rainfall is El Niño/Southern Oscillation. Also, the Sea Surface Temperature over the Atlantic Ocean is identified as an important climatic driver on the Amazon water cycle. Previously, observational datasets were used to support the Atlantic influence on Amazon rainfall. Furthermore, it is found that multiple global climate models do reproduce the Atlantic-Amazon link robustly. However, there exist differences in rainfall response, which primarily depends on the climatological rainfall amount.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoon, Jin -Ho

Amazon rainfall is subject to year-to-year fluctuation resulting in drought and flood in various intensities. A major climatic driver of the interannual variation of the Amazon rainfall is El Niño/Southern Oscillation. Also, the Sea Surface Temperature over the Atlantic Ocean is identified as an important climatic driver on the Amazon water cycle. Previously, observational datasets were used to support the Atlantic influence on Amazon rainfall. Furthermore, it is found that multiple global climate models do reproduce the Atlantic-Amazon link robustly. However, there exist differences in rainfall response, which primarily depends on the climatological rainfall amount.

A geomorphological assessments of the distribution of sediment sinks along the lower Amazon River

NASA Astrophysics Data System (ADS)

Park, E.; Latrubesse, E. M.

2017-12-01

Floodplain sediment storage budget is examined along the 1,000 km reach of the lower Amazon River based on extensive sets of remote sensing data and field measurements. Incorporating the washload discharges at gauge stations at the main channel and major tributaries, we analyzed the roles of vast floodplain on the Amazon River seasonal variability in sediment discharges. Annual washload accumulation rate on floodplain along the reach in between Manacapuru and Obidos of is estimated to be 79 Mt over inter-annual average. Period that the net loss over to the floodplain of washload coincide with discharge rising phase of the Amazon River at Obidos, when the river water level rises to make hydrologic connections to floodplain. Only during the early falling phase (July-August), 3.6 Mt of washload net gain occurred in a year, which was less than 5% of the annual net loss to the floodplain. To assess the spatial distribution of sediment sinks along the lower Amazon, we incorporated various hydro-geomorphic factors regarding floodplain geomorphic styles and morphometric parameters, such floodplain width, levee heights, water-saturated area, suspended sediment distribution over floodplain and distribution of impeded floodplain. Impeded floodplain that contains numerous large rounded lakes is the definition of active sediment sinks along the lower Amazon, which seasonally stores most of the water and traps sediment from the river. The results of these hydro-geomorphic factors collectively indicate that the extent and magnitudes of sediment sinks becomes larger downstream (from Manacapuru to Monte Alegre), which is proportionally related to the development of the water-saturated floodplain. This indicates the nonlinear geomorphic evolution of the Amazon floodplain through its longitudinal profile since the late Holocene that downstream reaches are still to be infilled with sediments (incomplete floodplain) thus acting as sediment sinks.

Potential groundwater contribution to Amazon evapotranspiration

NASA Astrophysics Data System (ADS)

Fan, Y.; Miguez-Macho, G.

2010-07-01

Climate and land ecosystem models simulate a dry-season vegetation stress in the Amazon forest, but observations show enhanced growth in response to higher radiation under less cloudy skies, indicating an adequate water supply. Proposed mechanisms include larger soil water store and deeper roots in nature and the ability of roots to move water up and down (hydraulic redistribution). Here we assess the importance of the upward soil water flux from the groundwater driven by capillarity. We present a map of water table depth from observations and groundwater modeling, and a map of potential capillary flux these water table depths can sustain. The maps show that the water table beneath the Amazon can be quite shallow in lowlands and river valleys (<5 m in 36% and <10 m in 60% of Amazonia). The water table can potentially sustain a capillary flux of >2.1 mm day-1 to the land surface averaged over Amazonia, but varies from 0.6 to 3.7 mm day-1 across nine study sites. Current models simulate a large-scale reduction in dry-season photosynthesis under today's climate and a possible dieback under projected future climate with a longer dry season, converting the Amazon from a net carbon sink to a source and accelerating warming. The inclusion of groundwater and capillary flux may modify the model results.

Characterization of Terrestrial Water Dynamics in the Congo Basin Using GRACE and Satellite Radar Altimetry

NASA Technical Reports Server (NTRS)

Lee, Hyongki; Beighley, R. Edward; Alsdorf, Douglas; Jung, Hahn Chul; Shum, C. K.; Duan, Jianbin; Guo, Junyi; Yamazaki, Dai; Andreadis, Konstantinos

2011-01-01

The Congo Basin is the world's third largest in size (approx.3.7 million sq km), and second only to the Amazon River in discharge (approx.40,200 cu m/s annual average). However, the hydrological dynamics of seasonally flooded wetlands and floodplains remains poorly quantified. Here, we separate the Congo wetland into four 3deg 3deg regions, and use remote sensing measurements (i.e., GRACE, satellite radar altimeter, GPCP, JERS-1, SRTM, and MODIS) to estimate the amounts of water filling and draining from the Congo wetland, and to determine the source of the water. We find that the amount of water annually filling and draining the Congo wetlands is 111 cu km, which is about one-third the size of the water volumes found on the mainstem Amazon floodplain. Based on amplitude comparisons among the water volume changes and timing comparisons among their fluxes, we conclude that the local upland runoff is the main source of the Congo wetland water, not the fluvial process of river-floodplain water exchange as in the Amazon. Our hydraulic analysis using altimeter measurements also supports our conclusion by demonstrating that water surface elevations in the wetlands are consistently higher than the adjacent river water levels. Our research highlights differences in the hydrology and hydrodynamics between the Congo wetland and the mainstem Amazon floodplain.

Characterization of Terrestrial Water Dynamics in the Congo Basin Using GRACE and Satellite Radar Altimetry

NASA Technical Reports Server (NTRS)

Lee, Lyongki; Beighley, R. Edward; Alsdorf, Douglas; Jung, Hahn Chul; Shum, C. K.; Duan, Jianbin; Guo, Junyi; Yamazaki, Dai; Andreadis, Konstantinos

2011-01-01

The Congo Basin is the world's third largest in size (approximately 3.7 million km^2), and second only to the Amazon River in discharge (approximately 40,200 cms annual average). However, the hydrological dynamics of seasonally flooded wetlands and floodplains remains poorly quantified. Here, we separate the Congo wetland into four 3 degree x 3 degree regions, and use remote sensing measurements (i.e., GRACE, satellite radar altimeter, GPCP, JERS-1, SRTM, and MODIS) to estimate the amounts of water filling and draining from the Congo wetland, and to determine the source of the water. We find that the amount of water annually filling and draining the Congo wetlands is 111 km^3, which is about one-third the size of the water volumes found on the mainstem Amazon floodplain. Based on amplitude comparisons among the water volume changes and timing comparisons among their fluxes, we conclude that the local upland runoff is the main source of the Congo wetland water, not the fluvial process of river-floodplain water exchange as in the Amazon. Our hydraulic analysis using altimeter measurements also supports our conclusion by demonstrating that water surface elevations in the wetlands are consistently higher than the adjacent river water levels. Our research also highlights differences in the hydrology and hydrodynamics between the Congo wetland and the mainstem Amazon floodplain.

Foraminifera and Thecamoebians as hydrodynamic indicators for Amazon estuarine system

NASA Astrophysics Data System (ADS)

Laut, L. L.; Figueiredo, A. G.; Santos, V. F.; Souza-Vieira, S.

2007-05-01

The Amazon mangrove forest in Brazilian territory is one of the most extended in the world. It goes from Ponta do Tubarao (4S e 43W) to Cape Orange (5N e 51W) along 2,250 km of coast line. Because the Amazon River System influence, it can be divided into two regions; one with river influence toward north and the other without river influence. In order to characterize the mangrove environment hydrodynamic on both sides of the Amazon River System, foraminifera and thecamoebians assemblages were investigated in the sediment of two estuaries; Araguari to the North (1 15S - 50 30W) and Caete to the South (0 50S - 46 30W). For both estuaries forams and thecamoebians species distribution are atypical relative to other world regions. In both, there are only few calcareous forams and almost all are small and possible of being transported in suspension. Typical estuarine species were not identified. The typical mangrove forams which are agglutinated species were dominant in both estuaries. However, the Caete estuary has a large number of forams species (29), indicating better efficiency in mixing fresh and salt water in comparison to the Araguari. On the other hand, the Araguari has big richness of thecamoebians species (15) indicating fresh water prevalence. The fresh water predominance is due to the Amazon water plume being diverted to the Amapa coast where the Araguari estuary is located. The foraminifera species was also used to determine the salt water penetration in the estuary. In the Caete estuary, salt water penetrates to about 40 km while in the Araguari it does coincide with the limit of the bore tide wave "pororoca" penetration, 45 km. Based on the species succession (forams to thecamoebians species) the Araguary estuary can be divided into three regions controlled by turbidity: the outer, middle and inner estuary. The Caete species succession is not that clear and only could be divided based on salinity into outer and inner estuary. In both estuaries forams and thecamoebians assemblages are efficient tools to distinguish hydrodynamic patterns. The Amazon water plume flowing toward North interferes in salt water penetration in the Araguari estuary, which inhibits forams development but favoring the thecamoebians. On the Amazon south side, the macrotidal regime and smaller volume of fresh water in the estuaries contribute to fresh and salt water mixing and thus resulting in homogeneity of forams and thecamoebians species distribution.

Asynchronous Amazon forest canopy phenology indicates adaptation to both water and light availability

NASA Astrophysics Data System (ADS)

Jones, Matthew O.; Kimball, John S.; Nemani, Ramakrishna R.

2014-12-01

Amazon forests represent nearly half of all tropical vegetation biomass and, through photosynthesis and respiration, annually process more than twice the amount of estimated carbon (CO2) from fossil fuel emissions. Yet the seasonality of Amazon canopy cover, and the extent to which seasonal fluctuations in water availability and photosynthetically available radiation influence these processes, is still poorly understood. Implementing six remotely sensed data sets spanning nine years (2003-2011), with reported field and flux tower data, we show that southern equatorial Amazon forests exhibit a distinctive seasonal signal. Seasonal timing of water availability, canopy biomass growth and net leaf flush are asynchronous in regions with short dry seasons and become more synchronous across a west-to-east longitudinal moisture gradient of increasing dry season. Forest cover is responsive to seasonal disparities in both water and solar radiation availability, temporally adjusting net leaf flush to maximize use of these generally abundant resources, while reducing drought susceptibility. An accurate characterization of this asynchronous behavior allows for improved understanding of canopy phenology across contiguous tropical forests and their sensitivity to climate variability and drought.

Potential contribution of groundwater to dry-season ET in the Amazon

NASA Astrophysics Data System (ADS)

Miguez-Macho, Gonzalo; Fan, Ying

2010-05-01

Climate and land ecosystem models simulate vegetation stress in the Amazon forest in the dry season, but observations show enhanced growth in response to higher radiation under less cloudy skies indicating 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. We present observational and modeling evidence that the vast groundwater store, consequence of high annual rainfall combined with poor drainage in the Amazon, may provide a stable source for dry-season photosynthesis. The water table beneath the Amazon is sufficiently shallow (38% area <5m and 63% area <10m deep) as to contribute >2mm/day to dry-season evapotranspiration, a non-negligible portion of tower-observed flux of 3-4mm/day, the latter including canopy-interception loss and open-water evaporation. This may have important implications to our understanding of Amazonia ecosystem response and feedback to climate change. Current models, lacking groundwater, predict a significant reduction in dry-season photosynthesis under current climate and large-scale dieback under projected future climate converting the Amazon from a net carbon sink to a net source and accelerating warming. If groundwater is considered in the models, the magnitude of the responses and feedbacks may be reduced.

Conjoint Analysis of the Surface and Atmospheric Water Balances of the Andes-Amazon System

NASA Astrophysics Data System (ADS)

Builes-Jaramillo, Alejandro; Poveda, Germán

2017-04-01

Acknowledging the interrelation between the two branches of the hydrological cycle, we perform a comprehensive analysis of the long-term mean surface and atmospheric water balances in the Amazon-Andes River basins system. We estimate the closure of the water budgets based on the long-term approximation of the water balance equations, and estimate the imbalance between both atmospheric and surface budgets. The analysis was performed with observational and reanalysis datasets for the entire basin, for several sub-catchments inside the entire Amazon River basin and for two physical and geographical distinctive subsystems of the basin, namely upper Andean the low-lying Amazon River basin. Our results evidence that for the entire Amazon River basin the surface water balance can be considered to be in balance (P = 2225 mm.yr-1, ET= 1062 mm.yr-1, R= 965 mm.yr-1), whereas for the separated subsystems it not so clear, showing high discrepancies between observations and reanalysis datasets. In turn, the atmospheric budget does not close regardless of datasets or geographical disaggregation. Our results indicate that the amount of imbalance of the atmospheric branch of the water balance depends on the evaporation data source used. The imbalance calculated as I=(C/R)-1, where C is net moisture convergence (C= -∇Q where ∇Q is the net vertically integrated moisture divergence) and R the runoff,represents the difference between the two branches of the hydrological cycle. For the entire Amazon River basin we found a consistent negative imbalance driven by higher values of runoff, and when calculated for monthly time scales the imbalance is characterized by a high dependence on the Amazon dry season. The separated analysis performed to the Andes and Low-lying Amazonia subsystems unveils two shortcomings of the available data, namely a poor quality of the representation of surface processes in the reanalysis models (including precipitation and evapotranspiration), and the limitations that high altitudes and scarcity of information induce in capturing the dynamics of hydrological processes over the Andean region. Our results confirm the paramount importance of a joint analysis between the atmospheric and surface water budgets at the river basin level, in order to achieve a complete understanding of the hydrologic dynamics.

Effects of future land use on biogeography of aquatic ecosystems of Amazonia

NASA Astrophysics Data System (ADS)

Howard, E. A.; Coe, M. T.; Foley, J. A.; Costa, M. H.

2006-12-01

Amazonian ecosystems provide key ecosystem services, such as regulating the amount and timing of water and carbon flows through the Amazon Basin. Land use in these ecosystems affects regional water balance, which in turn affects biogeography of aquatic ecosystems, including wetlands and floodplains. We combined a hydrological model (Terrestrial Hydrology Model with Biogeochemistry, THMB), remote sensing observations (Hess et al. 2003), and empirical data to identify the distribution of aquatic biogeographic types throughout the central Amazon basin over time. We explored how future land-use scenarios for the Amazon Basin through 2030 (Soares-Filho et al. 2004) would modify the spatial and temporal patterns of aquatic ecosystems as compared to a baseline of natural potential vegetation cover under historical climate variability for the 20th century. We calibrated monthly simulation results with remotely sensed observations of flooded area and extent of different wetland categories for high and low water periods over a 1.7 million sq. km region of the central Amazon. Two additional dimensions of floodplain biogeography (river size and color) were added to provide insight into the geographic distribution of key ecosystem types and their flooding seasonality. For historical conditions, the model results reproduced regional differences in seasonal flood extent and timing north and south of the Amazon mainstem, reflecting the dominant climatic regimes. Black-water streams and medium-sized rivers, followed by large white-water rivers, were the most extensive types across the study region. However much of the black water was in areas likely to be influenced by white-water rivers while flooded. The monthly extent of flooded areas dominated by woody vegetation was consistently more strongly seasonal than non-woody areas. Also, the extent of flooding in muddy and semi-muddy rivers and floodplains tended to be more highly seasonal than in black- and clear-water areas. We discuss our efforts to use our simulation results to extrapolate and bound estimates and patterns of aquatic ecosystem extent in the Amazon River system under future land-use scenarios. Regional flooding variability has disproportionate effects on different ecosystem types, suggesting that persistent, long-term changes to flooding regimes may have long-lasting consequences for floodplain vegetation, wildlife, and human residents.

Forecasting Total Water Storage Changes in the Amazon basin using Atlantic and Pacific Sea Surface Temperatures

NASA Astrophysics Data System (ADS)

De Linage, C.; Famiglietti, J. S.; Randerson, J. T.

2013-12-01

Floods and droughts frequently affect the Amazon River basin, impacting the transportation, river navigation, agriculture, economy and the carbon balance and biodiversity of several South American countries. The present study aims to find the main variables controlling the natural interannual variability of terrestrial water storage in the Amazon region and to propose a modeling framework for flood and drought forecasting. We propose three simple empirical models using a linear combination of lagged spatial averages of central Pacific (Niño 4 index) and tropical North Atlantic (TNAI index) sea surface temperatures (SST) to predict a decade-long record of 3°, monthly terrestrial water storage anomalies (TWSA) observed by the Gravity Recovery And Climate Experiment (GRACE) mission. In addition to a SST forcing term, the models included a relaxation term to simulate the memory of water storage anomalies in response to external variability in forcing. Model parameters were spatially-variable and individually optimized for each 3° grid cell. We also investigated the evolution of the predictive capability of our models with increasing minimum lead times for TWSA forecasts. TNAI was the primary external forcing for the central and western regions of the southern Amazon (35% of variance explained with a 3-month forecast), whereas Niño 4 was dominant in the northeastern part of the basin (61% of variance explained with a 3-month forecast). Forcing the model with a combination of the two indices improved the fit significantly (p<0.05) for at least 64% of the grid cells, compared to models forced solely with Niño 4 or TNAI. The combined model was able to explain 43% of the variance in the Amazon basin as a whole with a 3-month lead time. While 66% of the observed variance was explained in the northeastern Amazon, only 39% of the variance was captured by the combined model in the central and western regions, suggesting that other, more local, forcing sources were important in these regions. The predictive capability of the combined model was monotonically degraded with increasing lead times. Degradation was smaller in the northeastern Amazon (where 49% of the variance was explained using a 8-month lead time versus 69% for a 1 month lead time) compared to the western and central regions of southern Amazon (where 22% of the variance was explained at 8 months versus 43% at 1 month). Our model may provide early warning information about flooding in the northeastern region of the Amazon basin, where floodplain areas are extensive and the sensitivity of floods to external SST forcing was shown to be high. This work also strengthens our understanding of the mechanisms regulating interannual variability in Amazon fires, as TWSA deficits may subsequently lead to atmospheric water vapor deficits and reduced cloudiness via water-limited evapotranspiration. Finally, this work helps to bridge the gap between the current GRACE mission and the follow-on gravity mission.

From where does the Amazon forest gets its water?

NASA Astrophysics Data System (ADS)

Miguez-Macho, G.; Fan, Y.

2016-12-01

The Amazon receives abundant annual rainfall but parts of it experience a multi-month dry season. Here we ask: what is the water source that sustains the dry-season ET? Where over the Amazon it is largely local and recent rain (hence ET shutting down in dry season), or past rain that is stored in the deep soils and the groundwater (deep roots tapping deep reservoirs sustaining ET), or is it rain that fell on higher grounds (through topography-driven lateral convergence)? Using synthesis of isotope and other tracer observations and basin-wide inverse modeling (shallow soil, deep soil, with and without groundwater, with and without dynamic rooting depth), we attempt to tease out these components. The results shed light on likely ET sources and how future global change may preferentially impact Amazon ecosystem functioning.

Flooding dynamics on the lower Amazon floodplain

NASA Astrophysics Data System (ADS)

Rudorff, C.; Melack, J. M.; Bates, P. D.

2013-05-01

We analyzed flooding dynamics of a large floodplain lake in the lower reach of the Amazon River for the period between 1995 through 2010. Floodplain inundation was simulated using the LISFLOOD-FP model, which combines one-dimensional river routing with two-dimensional overland flow, and a local hydrological model. Accurate representation of floodplain flows and inundation extent depends on the quality of the digital elevation model (DEM). We combined digital topography (derived from the Shuttle Radar Topography Mission) with extensive floodplain echo-sounding data to generate a hydraulically sound DEM. Analysis of daily water balances revealed that the dominant source of inflow alternated seasonally among direct rain and local runoff (October through January), Amazon River (March through August), and seepage (September). As inflows from the Amazon River increase during the rising limb of the hydrograph, regional floodwaters encounter the floodplain partially inundated from local hydrological inputs. At peak flow the floodplain routes, on average, 2.5% of the total discharge for this reach. The falling limb of the hydrograph coincides with the locally dry period, allowing seepage of water stored in sediments to become a dominant source. The average annual inflow from the Amazon River was 58.8 km3 (SD = 33.5), representing more than three thirds (80%) of inputs from all sources, with substantial inter-annual variability. The average annual net export of water from the floodplain to the Amazon River was 7.9 km3 (SD = 2.7).

Effects of seasonality and land-use change on carbon and water fluxes across the Amazon basin: synthesizing results from satellite-based remote sensing, towers, and models

NASA Astrophysics Data System (ADS)

Saleska, S.; Goncalves, L. G.; Baker, I.; Costa, M.; Poulter, B.; Christoffersen, B.; Da Rocha, H. R.; Didan, K.; Huete, A.; Imbuziero, H.; Kruijt, B.; Manzi, A.; von Randow, C.; Restrepo-Coupe, N.; Silva, R.; Tota, J.; Denning, S.; Gulden, L.; Rosero, E.; Zeng, X.

2008-12-01

Amazon forests play an important and complex role in the global carbon cycle, and important advances have been made in understanding Amazon processes in recent years. However, reconciling modeled mechanisms of carbon cycling with observations across scales remains a challenge. To better address this challenge, we initiated a Model intercomparison Project for the 'Large-Scale Biosphere Atmosphere Experiment in Amazonia' (LBA-MIP) to integrate modeling and observational studies for improved understanding of Amazon basin carbon cycling. Here, we report on the initial results of this project, which used the network of meteorological and climate data (sunlight, radiation, precipitation) from Amazon tower sites in forest and converted lands to drive a suite of 20 ecosystem models that simulate energy, water and CO2 fluxes. We compared model mechanisms to each other and to the relevant flux observations from those towers, as well as from satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS). Remote sensing and flux tower observations tend to show higher primary forest photosynthetic activity in the dry season than in the wet season in central Amazon, a broad pattern that is now captured in many models, but for different reasons. A reversal from the primary forest pattern was observed in areas converted to pasture, agriculture, or secondary forests, likely a consequence of the elimination of deep root access to deep soil waters which often persist through the dry season. Testing the models with observed fluxes under different land use patterns, and across different spatial scales with remote sensing, is enabling us to distinguish correct vs. incorrect model mechanisms and improve understanding of Amazon processes.

Estimating drought induced tree mortality in the Amazon rainforest: A simulation study with a focus on plant hydraulic processes

NASA Astrophysics Data System (ADS)

Papastefanou, P.; Fleischer, K.; Hickler, T.; Grams, T.; Lapola, D.; Quesada, C. A.; Zang, C.; Rammig, A.

2017-12-01

The Amazon basin was recently hit by severe drought events that were unprecedented in their severity and spatial extent, e.g. during 2005, 2010 and 2015/2016. Significant amounts of biomass were lost, turning large parts of the rainforest from a carbon sink into a carbon source. It is assumed that drought-induced tree mortality from hydraulic failure played an important role during these events and may become more frequent in the Amazon region in the future. Many state-of-the-art dynamic vegetation models do not include plant hydraulic processes and fail to reproduce observed rainforest responses to drought events, such as e.g. increased tree mortality. We address this research gap by developing a simple plant-hydraulic module for the dynamic vegetation model LPJ-GUESS. This plant-hydraulic module uses leaf water potential and cavitation as baseline processes to simulate tree mortality under drought stress. Furthermore, we introduce different plant strategies in the model, which describe e.g. differences in the stomatal regulation under drought stress. To parameterize and evaluate our hydraulic module, we use a set of available observational data from the Amazon region. We apply our model to the Amazon Basin and highlight similarities and differences across other measured and predicted drought responses, e.g. extrapolated observations and data derived from satellite measurements. Our results highlight the importance of including plant hydraulic processes in dynamic vegetation models to correctly predict vegetation dynamics under drought stress and show major differences on the vegetation dynamics depending on the selected plant strategies. We also identify gaps in process understanding of the triggering factors, the extent and the consequences of drought responses that hampers our ability to predict potential impact of future drought events on the Amazon rainforest.

United States Drug Enforcement Policy in Colombia: Conflict of Priorities in Controlling the Flow of Cocaine to the United States

DTIC Science & Technology

2002-01-01

the same amount of money. Today, for every acre of coca crops eradicated in southern Colombia, three acres of Amazon rainforest are cut down to...less accuracy. As a result, people, animals , water supplies and basic subsistence crops are as likely to be sprayed as the coca field. Although the... animals or aquatic life, the perception by the majority of Colombians is that Glyphosate spraying has caused both widespread crop damage and minor

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

NASA Astrophysics Data System (ADS)

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

2006-12-01

The study of global carbon cycle requires a precise knowledge of spatial and temporal distributions and exportation from continents to oceans. Organic carbon fluxes represent approximately half of the total carbon budget carried by rivers. Tropical rivers transport two third of the total organic carbon discharged into the world oceans but important gaps still exist in the knowledge of the tropical river carbon biochemistry. The Amazon River is responsible for 10% of the annual amount of organic carbon transported from rivers to oceans. The most important portion of total organic matter transported in the Amazon Basin is the dissolved fraction (between 80% and 95%). Amazonian annual flux of dissolved organic matter is directly related to hydrological variations. All rivers in the Amazon basin are characterized by monomodal hydrograms, with a low water period in october/november and a high water period in may/june. Temporal variations in Amazon dissolved organic carbon (3.0 to 9.1 mg l^{- 1}) are mainly controled by Negro River inputs. DOC and DON contributions from the Negro River can vary between 120 kgC s-1 and 520 kg C s-1, and between 5 kgN s--1 and 15 kgN s-1, during low and high water period, respectivelly. In the Negro River, during high water stages, while DOC concentrations are stable from the upstream stations to the downstream ones (about 11 mg l-1), discharge increases from 16000 to 46000 m3 s-1 and NOD can quintuple from upstream (0.071 mg l-1) to downstream (0.341 mg l-1). Then the nature of dissolved organic matter is variable (C/N ratio varied from 33 to 120 from upstream to downstream). During low water stages DOC concentrations are lower (mean DOC of 8.1 mg l-1) while DON is in the same range, discharge is about 10000 m3 s-1 at downstream stations of Negro River and the C/N ratio is lower and steadier along the River. Finaly, despite a low basin surface (12%) compared with the two other main Amazon tributaries, Solimões and Madeira Rivers, and a mean annual water input to Amazonas of 15%, the Negro River contributes with about 38% of the total organic dissolved carbon transported by the Amazon River.

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

NASA Technical Reports Server (NTRS)

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

2013-01-01

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

Methane flux from the Amazon River floodplain - Emissions during rising water

NASA Technical Reports Server (NTRS)

Bartlett, Karen B.; Crill, Patrick M.; Bonassi, Jose A.; Richey, Jeffrey E.; Harriss, Robert C.

1990-01-01

Methane flux data obtained during a period of high and falling water level in the course of the dry season of 1985 (the Amazon Boundary Layer Experiment, ABLE 2A) and a period of moderate and rising water during the wet season of 1987 (ABLE 2B) were used to characterize the influence of seasonal variations in the vegetation, water column depth, and chemistry, as well as atmospheric dynamics, on the methane flux from the Amazon River floodplain. It was found that the annual estimate of methane from wetlands is identical to the annual estimate made by Matthews and Fung (1987) (both at 111 Tg). However, it was found that peatlands between 50 and 70 N contribute 39 Tg, with the large areas of forested and nonforested bogs making up 37 Tg of this figure, while the figures of Matthews and Fung were 63 and 62 Tg, respectively.

Drinking water and rural schools in the Western Amazon: an environmental intervention study

PubMed Central

Ribeiro, Maura Regina; de Abreu, Luiz Carlos

2018-01-01

Background Although water and sanitation are considered human rights, worldwide approximately three of 10 people (2.1 billion) do not have access to safe drinking water. In 2016, 5.6 million students were enrolled in the 34% of Brazilian schools located in rural areas, but only 72% had a public water supply network. The objective was to evaluate effectiveness of environmental intervention for water treatment in rural schools of the Western Amazonia, and determine the efficacy of water treatment using a simplified chlorinator on potability standards for turbidity, fecal coliforms and Escherichia coli. Methods A simplified chlorinator was installed for treatment of potable water in 20 public schools in the rural area of Rio Branco municipality, Acre state, Brazil. Results Before the intervention, 20% (n = 4), 100% (n = 20) and 70% (n = 14) of schools had water that failed to meet potability standards for turbidity, fecal coliforms and E. coli, respectively. However, after intervention, 70% (p = 0.68), 75% (p < 0.001) and 100% (p < 0.001) of schools complied with potability standards. Discussion This intervention considerably improved schools’ water quality, thus decreasing children’s health vulnerability due to inadequate water. Ancillary activities including training, educational lectures, installation of equipment, supply of materials and supplies (65% calcium hypochlorite and reagents) were considered fundamental to achieving success full outcomes. Installation of a simplified chlorinator in rural schools of the Western Amazon is therefore proposed as a social technology aiming at social inclusion, as well as economic and environmental sustainability. PMID:29922512

Drinking water and rural schools in the Western Amazon: an environmental intervention study.

PubMed

Ribeiro, Maura Regina; de Abreu, Luiz Carlos; Laporta, Gabriel Zorello

2018-01-01

Although water and sanitation are considered human rights, worldwide approximately three of 10 people (2.1 billion) do not have access to safe drinking water. In 2016, 5.6 million students were enrolled in the 34% of Brazilian schools located in rural areas, but only 72% had a public water supply network. The objective was to evaluate effectiveness of environmental intervention for water treatment in rural schools of the Western Amazonia, and determine the efficacy of water treatment using a simplified chlorinator on potability standards for turbidity, fecal coliforms and Escherichia coli . A simplified chlorinator was installed for treatment of potable water in 20 public schools in the rural area of Rio Branco municipality, Acre state, Brazil. Before the intervention, 20% ( n = 4), 100% ( n = 20) and 70% ( n = 14) of schools had water that failed to meet potability standards for turbidity, fecal coliforms and E. coli , respectively. However, after intervention, 70% ( p = 0.68), 75% ( p < 0.001) and 100% ( p < 0.001) of schools complied with potability standards. This intervention considerably improved schools' water quality, thus decreasing children's health vulnerability due to inadequate water. Ancillary activities including training, educational lectures, installation of equipment, supply of materials and supplies (65% calcium hypochlorite and reagents) were considered fundamental to achieving success full outcomes. Installation of a simplified chlorinator in rural schools of the Western Amazon is therefore proposed as a social technology aiming at social inclusion, as well as economic and environmental sustainability.

Rivers in the sea - Can we quantify pigments in the Amazon and the Orinoco River plumes from space?

NASA Technical Reports Server (NTRS)

Muller-Karger, Frank E.; Walsh, John J.; Carder, Kendall L.; Zika, Rod G.

1989-01-01

Coastal Zone Color Scanner (CZCS) images of the western tropical Atlantic (1979-1982) were combined into monthly mean surface pigment fields. These suggest that Amazon River water flows along northeastern South America directly toward the Caribbean sea early in the year. After June, however, the North Brazil Current is shunted eastward, carrying a large fraction of Amazon water into the North Equatorial Countercurrent (NECC). This eastward flow causes diminished flow through the Caribbean, which permits northwestward dispersal of Orinoco River water due to local Ekman forcing. The Orinoco plume crosses the Caribbean, leading to seasonal variation in surface salinity near Puerto Rico. At least 50 percent of the pigment concentration estimated in these plumes seems due to viable phytoplankton.

Oil pollution in soils and sediments from the Northern Peruvian Amazon.

PubMed

Rosell-Melé, Antoni; Moraleda-Cibrián, Núria; Cartró-Sabaté, Mar; Colomer-Ventura, Ferran; Mayor, Pedro; Orta-Martínez, Martí

2018-01-01

Oil has been extracted from the Northern Peruvian Amazon for over four decades. However, few scientific studies have assessed the impacts of such activities in the environment and health of indigenous communities in the region. We have investigated the occurrence of petrogenic hydrocarbon pollution in soils and sediments from areas favoured as hunting or fishing grounds by local indigenous inhabitants. The study was conducted in one of the most productive oil blocks in Peru, located in the headwaters of the Amazon river. Soils and river sediments, in the vicinity of oil extraction and processing infrastructure, contained an oil pollution signature as attested by the occurrence of hopanes and steranes. Given the lack of any other significant source of oil pollution in the region, the sources of hydrocarbons are likely to be the activities of the oil industry in the oil block, from voluntary discharges or accidental spills. Spillage of produced water was commonplace until 2009. Moreover, petrogenic compounds were absent in control samples in sites far removed from any oil infrastructure in the oil block. Our findings suggest that wildlife and indigenous populations in this region of the Amazon are exposed to the ingestion of oil polluted soils and sediments. The data obtained supports previous claims that the local spillage of oil and produced waters in the water courses in the Corrientes and Pastaza basins could have eventually reached the main water course of the Amazon. Copyright © 2017 Elsevier B.V. All rights reserved.

Understanding the Impacts of Climate and Hydrologic Extremes on Diarrheal Diseases in Southwestern Amazon

NASA Astrophysics Data System (ADS)

Fonseca, P. A. M.

2015-12-01

Bacterial diarrheal diseases have a high incidence rate during and after flooding episodes. In the Brazilian Amazon, flood extreme events have become more frequent, leading to high incidence rates for infant diarrhea. In this study we aimed to find a statistical association between rainfall, river levels and diarrheal diseases in children under 5, in the river Acre basin, in the State of Acre (Brazil). We also aimed to identify the time-lag and annual season of extreme rainfall and flooding in different cities in the water basin. The results using Tropical Rainfall Measuring Mission (TRMM) Satellite rainfall data show robustness of these estimates against observational stations on-ground. The Pearson coefficient correlation results (highest 0.35) indicate a time-lag, up to 4 days in three of the cities in the water-basin. In addition, a correlation was also tested between monthly accumulated rainfall and the diarrheal incidence during the rainy season (DJF). Correlation results were higher, especially in Acrelândia (0.7) and Brasiléia and Epitaciolândia (0.5). The correlation between water level monthly averages and diarrheal diseases incidence was 0.3 and 0.5 in Brasiléia and Epitaciolândia. The time-lag evidence found in this paper is critical to inform stakeholders, local populations and civil defense authorities about the time available for preventive and adaptation measures between extreme rainfall and flooding events in vulnerable cities. This study was part of a pilot application in the state of Acre of the PULSE-Brazil project (http://www.pulse-brasil.org/tool/), an interface of climate, environmental and health data to support climate adaptation. The next step of this research is to expand the analysis to other climate variables on diarrheal diseases across the whole Brazilian Amazon Basin and estimate the relative risk (RR) of a child getting sick. A statistical model will estimate RR based on the observed values and seasonal forecasts (higher accuracy for the Amazon region) will be used so the government can be prepared for extreme climate events forecasted. It is expected that these results can be helpful during and post extreme events to improve health surveillance preparedness and better allocate available results in adapting vulnerable cities to climate extreme events.

Holocene palaeoenvironmental history of the Amazonian mangrove belt

NASA Astrophysics Data System (ADS)

Cohen, Marcelo Cancela Lisboa; Pessenda, Luiz Carlos Ruiz; Behling, Hermann; de Fátima Rossetti, Dilce; França, Marlon Carlos; Guimarães, José Tasso Felix; Friaes, Yuri; Smith, Clarisse Beltrão

2012-11-01

Wetland dynamic in the northern Brazilian Amazon region during the Holocene was reviewed using palynological, carbon and nitrogen isotopes records, and C/N ratio previously published. The integration of 72 radiocarbon dates recorded in 34 sediment cores sampled along the marine and fluvial littoral, and mainly influenced by the Amazon River, reveals that marine influence and mangrove vegetation were wider than today on the mouth of Amazon River between >8990-8690 and 2300-2230 cal yr BP, forming a continuous mangrove belt along the northern Brazilian Amazon littoral. The establishment of this mangrove strip is a direct consequence of the marine incursion caused by post-glacial sea-level rise possibly associated with tectonic subsidence during the Early and Middle Holocene. In the Late Holocene, in areas influenced by the Amazon River discharge, the mangroves were replaced by freshwater vegetation, and the coast morphology evolved from an estuarine dominated into a rectilinear coast due to coastal progradation. Nevertheless, the marine-influenced littoral, which is currently dominated by mangroves and salt-marsh vegetation, has persistently had brackish water vegetation over tidal mud flats throughout the entire Holocene. Likely, the fragmentation of this continuous mangrove line during the Late Holocene was caused by the increase of river freshwater discharge associated to the change from dry into wet climates in the Late Holocene. This caused a significant decrease of tidal water salinity in areas near the mouth of Amazon River. These changes in the Amazon discharge are probably associated with dry and wet periods in the northern Amazon region during the Holocene.

A Simulation Model of Carbon Cycling and Methane Emissions in Amazon Wetlands

NASA Technical Reports Server (NTRS)

Potter, Christopher; Melack, John; Hess, Laura; Forsberg, Bruce; Novo, Evlyn Moraes; Klooster, Steven

2004-01-01

An integrative carbon study is investigating the hypothesis that measured fluxes of methane from wetlands in the Amazon region can be predicted accurately using a combination of process modeling of ecosystem carbon cycles and remote sensing of regional floodplain dynamics. A new simulation model has been build using the NASA- CASA concept for predicting methane production and emission fluxes in Amazon river and floodplain ecosystems. Numerous innovations area being made to model Amazon wetland ecosystems, including: (1) prediction of wetland net primary production (NPP) as the source for plant litter decomposition and accumulation of sediment organic matter in two major vegetation classes - flooded forests (varzea or igapo) and floating macrophytes, (2) representation of controls on carbon processing and methane evasion at the diffusive boundary layer, through the lake water column, and in wetland sediments as a function of changes in floodplain water level, (3) inclusion of surface emissions controls on wetland methane fluxes, including variations in daily surface temperature and of hydrostatic pressure linked to water level fluctuations. A model design overview and early simulation results are presented.

First report of Panstrongylus megistus (Hemiptera, Reduviidae, Triatominae) in the State of Acre and Rondônia, Amazon, Brazil.

PubMed

Ribeiro Castro, Mariane Albuquerque Lima; de Souza Castro, Gabriela Vieira; de Souza, Janis Lunier; de Souza, Cláudio Rodrigues; Ramos, Leandro José; de Oliveira, Jader; da Rosa, João Aristeu; Aranha Camargo, Luis Marcelo; Meneguetti, Dionatas Ulises de Oliveira

2018-06-01

This article reports, for the first time, the occurrence of Panstrongylus megistus in the Brazilian Western Amazon. Specimens of P. megistus were collected in the cities of Rio Branco, Acre and Extrema, Rondônia. The number of triatomine species in the State of Acre increased from eight to nine and in Rondônia from seven to eight. This was also the first report of P. megistus in the Brazilian Western Amazon. The occurrence of P. megistus in the Western Amazon evidences an epidemiological alert, since it is an important vector of T. cruzi. Copyright © 2018 Elsevier B.V. All rights reserved.

The density and biomass of mesozooplankton and ichthyoplankton in the Negro and the Amazon Rivers during the rainy season: the ecological importance of the confluence boundary

PubMed Central

Rimachi, Elvis V.; Santos-Silva, Edinaldo N.; Calixto, Laura S.F.; Leite, Rosseval G.; Khen, Adi; Yamane, Tetsuo; Mazeroll, Anthony I.; Inuma, Jomber C.; Utumi, Erika Y.K.; Tanaka, Akira

2017-01-01

The boundary zone between two different hydrological regimes is often a biologically enriched environment with distinct planktonic communities. In the center of the Amazon River basin, muddy white water of the Amazon River meets with black water of the Negro River, creating a conspicuous visible boundary spanning over 10 km along the Amazon River. Here, we tested the hypothesis that the confluence boundary between the white and black water rivers concentrates prey and is used as a feeding habitat for consumers by investigating the density, biomass and distribution of mesozooplankton and ichthyoplankton communities across the two rivers during the rainy season. Our results show that mean mesozooplankton density (2,730 inds. m−3) and biomass (4.8 mg m−3) were higher in the black-water river compared to the white-water river (959 inds. m−3; 2.4 mg m−3); however an exceptionally high mesozooplankton density was not observed in the confluence boundary. Nonetheless we found the highest density of ichthyoplankton in the confluence boundary (9.7 inds. m−3), being up to 9-fold higher than in adjacent rivers. The confluence between white and black waters is sandwiched by both environments with low (white water) and high (black water) zooplankton concentrations and by both environments with low (white water) and high (black water) predation pressures for fish larvae, and may function as a boundary layer that offers benefits of both high prey concentrations and low predation risk. This forms a plausible explanation for the high density of ichthyoplankton in the confluence zone of black and white water rivers. PMID:28507821

The density and biomass of mesozooplankton and ichthyoplankton in the Negro and the Amazon Rivers during the rainy season: the ecological importance of the confluence boundary.

PubMed

Nakajima, Ryota; Rimachi, Elvis V; Santos-Silva, Edinaldo N; Calixto, Laura S F; Leite, Rosseval G; Khen, Adi; Yamane, Tetsuo; Mazeroll, Anthony I; Inuma, Jomber C; Utumi, Erika Y K; Tanaka, Akira

2017-01-01

The boundary zone between two different hydrological regimes is often a biologically enriched environment with distinct planktonic communities. In the center of the Amazon River basin, muddy white water of the Amazon River meets with black water of the Negro River, creating a conspicuous visible boundary spanning over 10 km along the Amazon River. Here, we tested the hypothesis that the confluence boundary between the white and black water rivers concentrates prey and is used as a feeding habitat for consumers by investigating the density, biomass and distribution of mesozooplankton and ichthyoplankton communities across the two rivers during the rainy season. Our results show that mean mesozooplankton density (2,730 inds. m -3 ) and biomass (4.8 mg m -3 ) were higher in the black-water river compared to the white-water river (959 inds. m -3 ; 2.4 mg m -3 ); however an exceptionally high mesozooplankton density was not observed in the confluence boundary. Nonetheless we found the highest density of ichthyoplankton in the confluence boundary (9.7 inds. m -3 ), being up to 9-fold higher than in adjacent rivers. The confluence between white and black waters is sandwiched by both environments with low (white water) and high (black water) zooplankton concentrations and by both environments with low (white water) and high (black water) predation pressures for fish larvae, and may function as a boundary layer that offers benefits of both high prey concentrations and low predation risk. This forms a plausible explanation for the high density of ichthyoplankton in the confluence zone of black and white water rivers.

Self-amplified Amazon forest loss due to vegetation-atmosphere feedbacks.

PubMed

Zemp, Delphine Clara; Schleussner, Carl-Friedrich; Barbosa, Henrique M J; Hirota, Marina; Montade, Vincent; Sampaio, Gilvan; Staal, Arie; Wang-Erlandsson, Lan; Rammig, Anja

2017-03-13

Reduced rainfall increases the risk of forest dieback, while in return forest loss might intensify regional droughts. The consequences of this vegetation-atmosphere feedback for the stability of the Amazon forest are still unclear. Here we show that the risk of self-amplified Amazon forest loss increases nonlinearly with dry-season intensification. We apply a novel complex-network approach, in which Amazon forest patches are linked by observation-based atmospheric water fluxes. Our results suggest that the risk of self-amplified forest loss is reduced with increasing heterogeneity in the response of forest patches to reduced rainfall. Under dry-season Amazonian rainfall reductions, comparable to Last Glacial Maximum conditions, additional forest loss due to self-amplified effects occurs in 10-13% of the Amazon basin. Although our findings do not indicate that the projected rainfall changes for the end of the twenty-first century will lead to complete Amazon dieback, they suggest that frequent extreme drought events have the potential to destabilize large parts of the Amazon forest.

Self-amplified Amazon forest loss due to vegetation-atmosphere feedbacks

NASA Astrophysics Data System (ADS)

Zemp, Delphine Clara; Schleussner, Carl-Friedrich; Barbosa, Henrique M. J.; Hirota, Marina; Montade, Vincent; Sampaio, Gilvan; Staal, Arie; Wang-Erlandsson, Lan; Rammig, Anja

2017-03-01

Reduced rainfall increases the risk of forest dieback, while in return forest loss might intensify regional droughts. The consequences of this vegetation-atmosphere feedback for the stability of the Amazon forest are still unclear. Here we show that the risk of self-amplified Amazon forest loss increases nonlinearly with dry-season intensification. We apply a novel complex-network approach, in which Amazon forest patches are linked by observation-based atmospheric water fluxes. Our results suggest that the risk of self-amplified forest loss is reduced with increasing heterogeneity in the response of forest patches to reduced rainfall. Under dry-season Amazonian rainfall reductions, comparable to Last Glacial Maximum conditions, additional forest loss due to self-amplified effects occurs in 10-13% of the Amazon basin. Although our findings do not indicate that the projected rainfall changes for the end of the twenty-first century will lead to complete Amazon dieback, they suggest that frequent extreme drought events have the potential to destabilize large parts of the Amazon forest.

Self-amplified Amazon forest loss due to vegetation-atmosphere feedbacks

PubMed Central

Zemp, Delphine Clara; Schleussner, Carl-Friedrich; Barbosa, Henrique M. J.; Hirota, Marina; Montade, Vincent; Sampaio, Gilvan; Staal, Arie; Wang-Erlandsson, Lan; Rammig, Anja

2017-01-01

Reduced rainfall increases the risk of forest dieback, while in return forest loss might intensify regional droughts. The consequences of this vegetation–atmosphere feedback for the stability of the Amazon forest are still unclear. Here we show that the risk of self-amplified Amazon forest loss increases nonlinearly with dry-season intensification. We apply a novel complex-network approach, in which Amazon forest patches are linked by observation-based atmospheric water fluxes. Our results suggest that the risk of self-amplified forest loss is reduced with increasing heterogeneity in the response of forest patches to reduced rainfall. Under dry-season Amazonian rainfall reductions, comparable to Last Glacial Maximum conditions, additional forest loss due to self-amplified effects occurs in 10–13% of the Amazon basin. Although our findings do not indicate that the projected rainfall changes for the end of the twenty-first century will lead to complete Amazon dieback, they suggest that frequent extreme drought events have the potential to destabilize large parts of the Amazon forest. PMID:28287104

Selective logging in the Brazilian Amazon.

Treesearch

G. P. Asner; D. E. Knapp; E. N. Broadbent; P. J. C. Oliveira; M Keller; J. N. Silva

2005-01-01

Amazon deforestation has been measured by remote sensing for three decades. In comparison, selective logging has been mostly invisible to satellites. We developed a large-scale, high-resolution, automated remote-sensing analysis of selective logging in the top five timber-producing states of the Brazilian Amazon. Logged areas ranged from 12,075 to 19,823 square...

Accord No. 334 of 18 August 1989.

PubMed

1989-01-01

This Accord creates the Programme for Forestation and Reforestation of the Amazon Region of Ecuador with Native Species, under the control of the National Forestry Directorate. The preamble to the Accord states that the Programme has been created, in part, to stop the indiscriminate exploitation of natural trees. Accord No. 332 of 18 August 1989, issued by the Ministry of Agriculture and Livestock, creates under the Regional Subsecretariat for the Amazon the Agency of Natural Resources of the Amazon Region of Ecuador to coordinate activities taking place in that area with the Institute for Settlement of the Amazon Region of Ecuador and relevant state organizations. The preamble to the Accord states that the Agency has been created, in part, to ensure the rational and harmonic development of the region and to preserve the region's natural resources. See Registro Oficial, No. 262, 28 August 1989, p. 2.

Reactive and dissolved meteoric 10Be/9Be ratios in the Amazon basin

NASA Astrophysics Data System (ADS)

Wittmann, Hella; Dannhaus, Nadine; von Blanckenburg, Friedhelm; Bouchez, Julien; Suessenberger, Annette; Guyot, Jean-Loup; Maurice, Laurence; Filizola, Naziano; Gaillardet, Jerome; Christl, Marcus

2014-05-01

Recently, the ratio of the meteoric cosmogenic nuclide 10Be to stable 9Be has been established as a weathering and erosion proxy where meteoric 10Be/9Be ratios in reactive phases of secondary weathering products leached from detrital Amazonian river sediment were measured[1]. For this dataset, we derived a new 10Be-based mass balance, which compares the fluxes exported during erosion and weathering, Fout, calculated by the sum of [10Be]reac multiplied by gauging-derived sediment discharge and [10Be]dissmultiplied by water discharge, to the meteoric depositional flux Fin. This assessment allows evaluating the weathering state of the Amazon basin. Further, in order to assess equilibration of reactive phases in the water column, we measured (10Be/9Be)reac ratios leached from suspended sediments for two depth profiles of the Amazon (55m depth) and Madeira (12m depth) Rivers, their corresponding surface dissolved 10Be/9Be ratios, as well as dissolved ratios of smaller Amazon tributaries (Beni, Madre de Dios) to compare with published reactive ratios[1]. In these rivers, modest pH and salinity fluctuations help to constrain a 'simple' system that might however still be affected by seasonally changing isotopic compositions between water and suspended sediment[2] and seasonal fluctuations of TSS and TDS[3]. The 10Be-based mass balance shows that in Andean source areas Fout/Fin ≡1, indicating a balance between ingoing and exported flux, whereas in the Shield headwaters, Fout/Fin=0.3, indicating a combination of decay of 10Be during storage and little export of 10Be associated with particulate and dissolved loads. In central Amazonia, the export of 10Be decreases slightly relative to its atmospheric flux as evidenced by Fout/Fin=0.8 for the Amazon and Madeira Rivers. This value is interpreted as being close to steady state, but its modification could be due to additions of Shield-derived sediment to sediment carried in the main river[4]. Regarding the depth profiles, our preliminary findings stress that the (10Be/9Be)reac for the Amazon River (n=3, Avg.= 5.4x10-10with SD=3.7x10-11) and the Madeira River (n=3, Avg.= 4x10-10with SD=2.1x10-11) do not change significantly within the water column. These depth-dependent reactive ratios compare well with 10Be/9Be ratios of surface waters and sediments and with published data available for the Negro and Orinoco[5]: For all these large rivers, surface (10Be/9Be)reac vs. (10Be/9Be)dissagree very well (R2 ≡1). For smaller tributaries like the Apure, La Tigra, Beni and Madre de Dios, (10Be/9Be)reacare 2-3 times lower than (10Be/9Be)diss. As pH values are similar for all these rivers, one possibility is that in smaller river systems mixing of sediment and water between the channel and the floodplain is less thorough, potentially resulting in reactive and dissolved phases that are not fully equilibrated. For large rivers, however, our depth-invariant (10Be/9Be)reac data indicate consistent and probably early equilibration of Be with depth. We also do not observe potentially divergent 10Be/9Be ratios due to e.g. floodplain remobilization or different erosion rates in the source area. From this, we infer a thorough mixing of the clay/silt fraction within large rivers, with the different 10Be/9Be ratios of Madeira and Amazon Rivers fingerprinting the different prevailing denudation rates of the source areas (Andes and Brazilian Shield). The here presented results suggest that one surface sample, either reactive or dissolved, would be sufficient to determine denudation rates of an entire catchment. [1] F. von Blanckenburg et al., EPSL, 351-352 (2012) 295-305. [2] J. Viers, et al., EPSL, 274 (2008) 511-523. [3] J. Bouchez, et al., Geochem. Geophys. Geosys. 12 (2011) Q03008. [4] H. Wittmann et al., Geology 39 (2011) 467-470. [5] E. T. Brown et al., GCA 56 (1992) 1607-1624.

Asynchronous Amazon Forest Canopy Phenology Indicates Adaptation to Both Water and Light Availability

NASA Astrophysics Data System (ADS)

Jones, M. O.; Kimball, J. S.; Nemani, R. R.

2015-12-01

Amazon forests represent nearly half of all tropical vegetation biomass and, through photosynthesis and respiration, annually process more than twice the amount of estimated carbon (CO2) from fossil fuel emissions. Yet the seasonality of Amazon canopy cover, and the extent to which seasonal fluctuations in water availability and photosynthetically active radiation influence these processes, is still poorly understood. Implementing six remotely sensed data sets spanning nine years (2003-2011), with reported field and flux tower data, we show that southern equatorial Amazon forests exhibit a distinctive seasonal signal. Seasonal timing of water availability, canopy biomass growth and net leaf flush are asynchronous in regions with short dry seasons and become more synchronous across a west-to-east longitudinal moisture gradient of increasing dry season length. Forest cover is responsive to seasonal disparities in both water and solar radiation availability, temporally adjusting net leaf flush to maximize use of these generally abundant resources, while reducing drought susceptibility. An accurate characterization of this asynchronous behavior allows for improved understanding of canopy phenology across contiguous tropical forests and their sensitivity to climate variability and drought. These insights can also inform land surface models to provide a more accurate representation of seasonal forest carbon allocation strategies responsive to environmental drivers.

Deforestation effects on Amazon forest resilience

NASA Astrophysics Data System (ADS)

Zemp, D. C.; Schleussner, C.-F.; Barbosa, H. M. J.; Rammig, A.

2017-06-01

Through vegetation-atmosphere feedbacks, rainfall reductions as a result of Amazon deforestation could reduce the resilience on the remaining forest to perturbations and potentially lead to large-scale Amazon forest loss. We track observation-based water fluxes from sources (evapotranspiration) to sinks (rainfall) to assess the effect of deforestation on continental rainfall. By studying 21st century deforestation scenarios, we show that deforestation can reduce dry season rainfall by up to 20% far from the deforested area, namely, over the western Amazon basin and the La Plata basin. As a consequence, forest resilience is systematically eroded in the southwestern region covering a quarter of the current Amazon forest. Our findings suggest that the climatological effects of deforestation can lead to permanent forest loss in this region. We identify hot spot regions where forest loss should be avoided to maintain the ecological integrity of the Amazon forest.

Radionuclide tracers of sediment-water interactions on the Amazon shelf

NASA Astrophysics Data System (ADS)

Moore, Willard S.; DeMaster, David J.; Smoak, Joseph M.; McKee, Brent A.; Swarzenski, Peter W.

1996-04-01

A comprehensive study of a variety of radionuclide tracers has been coupled with other geochemical investigations and with sedimentary and physical oceanographic measurements to elucidate processes and their characteristic time scales at the mouth of the Amazon River. This two-year field study on the Amazon continental shelf involved four cruises designed to provide information during different stages of the river hydrograph. Although the cruises were coordinated with river stage, other physical variables including spring-neap tidal stages, the flow of the North Brazil Current and trade-wind stress caused important effects on the shelf environment. Partitioning of uranium among dissolved, colloidal and particulate phases was investigated during AmasSeds. A detailed examination of uranium water-column behavior during low river discharge found that most (89%) of the uranium near the Amazon River mouth was associated with the particulate phase and that most (92%) of the riverine dissolved-phase uranium was in the colloidal size fraction (0.001-0.4 μm). A non-conservative uranium/salinity distribution was observed for dissolved uranium, indicating large-scale uranium removal from surface waters with salinities less than 20 ppt. Colloidal uranium was non-conservative across the entire salinity regime, exhibiting removal of colloidal uranium from waters with salinities less than 12 ppt and a significant input at higher salinities. A short-lived particle-reactive tracer, 234Th, was used to evaluate the rates of particle scavenging on the shelf. Suspended-sediment concentrations respond to each turn of the tide, thus limiting the time available for equilibrium to be established between the particles and the tracers. Experiments demonstrated that on the Amazon shelf the partitioning and distribution of trace elements are governed by particle dynamics (particle residence times < sorption times). The high suspended load, including fluid muds, retards the incorporation of adsorbed 234Th into the seabed. Once scavenged, 234Th remains part of the suspended-sediment and fluid-mud inventory for periods of at least 4-8 weeks. Another particle-reactive tracer, 210Pb, was used to evaluate the potential supply of reactive metals from offshore waters to the shelf. As open-ocean waters move into the Amazon mixing zone, in response to the estuarine-like circulation, they lose 210Ph through scavenging processes associated with delta formation. This oceanic input of 210Pb dominates other inputs to the Amazon shelf system. Based on 210Pb analyses from more than 40 ☐ and kasten cores, the flux of water moving shoreward and depositing 210Pb in the sediments was calculated to be on the order of 6 × 10 161y -1 ˜10 times the riverine flux from the Amazon. The distribution of 210Pb in the sediments suggests that if particle-reactive species (such as certain trace metals) are released in dissolved form on the shelf, they will be scavenged quickly in this turbid environment, with the largest inventories occurring in the foreset beds (although the highest concentrations occur in the bottomset beds). The large landward flow of water indicates that if particle-reactive species are released in the western equatorial Atlantic via aerosol transport or other mechanisms, there is a good chance that a sizeable portion will be buried in the Amazon delta. Fluxes of radium isotopes, 226Ra, 228Ra and 224Ra, from the bottom sediments were used to evaluate sediment resuspension across the shelf. The average flux of 226Ra from the Amazon shelf balanced the annual desorption of 226Ra from river-derived sediments; however, departures between the 226Ra flux and sediment necessary to support the flux occurred for different sampling periods. During falling and low discharge, less sediment entered the system than was required to support the sedimentary desorption 226Ra flux. During rising and high discharge, more sediment entered than was necessary to sustain the 226Ra flux. Considerable recycling of particles between the seabed and water column was required to wash away most of the desorbable 226Ra from the sediment. To support the sedimentary 228Ra flux, 3.4 × 10 16 g of sediment must be resuspended each year. Such mixing would resuspend the top 35 em of sediment over the entire shelf each year, or mix the surface layer (SL, the region of uniform sedimentary 210Pb depth profiles) to a depth of 90 cm annually. Such mixing would turn over the entire SL every 1-2 years. Desorption of sedimentary radium isotopes must be accompanied by the desorption of other exchangeable species including phosphate, cesium and cadmium. Correlations among phosphate and radium isotopes, infer that phosphate is being released from bottom sediments as the sediments are resuspended into the water column. As was the case for 226Ra, bottom sediment must be repeatedly suspended into the water column to release all of the exchangeable phosphate. The desorption of 224Ra from shelf sediments provides a tracer of the Amazon plume into the Atlantic. In July and September 1989, the ship crossed the Demerara retroflection 380 km from the Amazon shelf and excess 224Ra activities up to 8 dpm 100 kg -1 were measured. It was concluded that these waters were <5 days removed from the Amazon shelf. A sustained current of >80 em s -1 would be required to advect the water this distance in <5 days, an observation that agrees well with drogue releases during August 1989.

Atmospheric surface and boundary layers of the Amazon Basin

NASA Technical Reports Server (NTRS)

Garstang, Michael

1987-01-01

Three phases of work were performed: design of and preparation for the Amazon Boundary Layer Experiment (ABLE 2-A); execution of the ABLE 2-A field program; and analysis of the ABLE 2-A data. Three areas of experiment design were dealt with: surface based meteorological measurements; aircraft missions; and project meteorological support. The primary goal was to obtain a good description of the structure of the atmosphere immediately above the rain forest canopy (top of canopy to a few thousand meters), to describe this region during the growing daytime phase of the boundary layer; and to examine the nighttime stratified state. A secondary objective was to examine the role that deep convective storms play in the vertical transport of heat, water vapor, and other trace gases. While significant progress was made, much of the analysis remains to be done.

Suspended sediments of the modern Amazon and Orinoco rivers

USGS Publications Warehouse

Meade, R.H.

1994-01-01

The Amazon and Orinoco Rivers are massive transcontinental conveyance systems for suspended sediment. They derive about 90% of their sediment from the Andes that support their western headwaters, transport it for thousands of kilometers across the breadth of the continent and deposit it in the coastal zones of the Atlantic. At their points of maximum suspended-sediment discharge, the Amazon transports an average of 1100-1300 ?? 106 tons per year and the Orinoco transports about 150 ?? 106 tons per year. Relations of sediment discharge to water discharge are complicated by unusual patterns of seasonal storage and remobilization, increased storage and reduced transport of sediment in the middle Orinoco during periods of peak water discharge, and storage of suspended sediment in the lower Amazon during rising discharge and resuspension during falling discharge. Spatial distributions of suspended sediment in cross-sections of both rivers are typically heterogeneous, not only in the vertical sense but also in the lateral. The cross-channel mixing of tributary inputs into the mainstem waters is a slow process that requires several hundred kilometers of downriver transport to complete. Considerable fine-grained sediment is exchanged between rivers and floodplains by the combination of overbank deposition and bank erosion. ?? 1994.

Seasonal uranium distributions in the coastal waters off the Amazon and Mississippi Rivers

USGS Publications Warehouse

Swarzenski, P.W.; McKee, B.A.

1998-01-01

The chemical reactivity of uranium was investigated across estuarine gradients from two of the world's largest river systems: the Amazon and Mississippi. Concentrations of dissolved (<0.45 ??m) uranium (U) were measured in surface waters of the Amazon shelf during rising (March 1990), flood (June 1990) and low (November 1991) discharge regimes. The dissolved U content was also examined in surface waters collected across estuarine gradients of the Mississippi outflow region during April 1992, August 1993, and November (1993). All water samples were analyzed for U by isotope dilution inductively coupled plasma mass spectrometry (ICP-MS). In Amazon shelf surface waters uranium increased nonconservatively from about 0.01 ??g l-1 at the river's mouth to over 3 ??g l-1 at the distal site, irrespective of river discharge stage. Observed large-scale U removal at salinities generally less than 15 implies a) that riverine dissolved U was extensively adsorbed by freshly-precipitated hydrous metal oxides (e.g., FeOOH, MnO2) as a result of flocculation and aggregation, and b) that energetic resuspension and reworking of shelf sediments and fluid muds on the Amazon shelf released a chemically reactive particle/colloid to the water column which can further scavenge dissolved U across much of the estuarine gradient. In contrast, the estuarine chemistry of U is inconclusive within surface waters of the Mississippi shelf-break region. U behavior is most likely controlled less by traditional sorption and/or desorption reactions involving metal oxides or colloids than by the river's variable discharge regime (e.g., water parcel residence time during estuarine mixing, nature of particulates, sediment storage and resuspension in the confined lower river), and plume dispersal. Mixing of the thin freshwater lens into ambient seawater is largely defined by wind-driven rather than physical processes. As a consequence, in the Mississippi outflow region uranium predominantly displays ConserVative behavior; removal is evident only during anomalous river discharge regimes. 'Products-approach' mixing experiments conducted during the Flood of 1993 suggest the importance of small particles and/or colloids in defining a depleted U versus salinity distribution.

Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought

NASA Astrophysics Data System (ADS)

Li, Xing; Xiao, Jingfeng; He, Binbin

2018-04-01

Amazon forests play an important role in the global carbon cycle and Earth’s climate. The vulnerability of Amazon forests to drought remains highly controversial. Here we examine the impacts of the 2015 drought on the photosynthesis of Amazon forests to understand how solar radiation and precipitation jointly control forest photosynthesis during the severe drought. We use a variety of gridded vegetation and climate datasets, including solar-induced chlorophyll fluorescence (SIF), photosynthetic active radiation (PAR), the fraction of absorbed PAR (APAR), leaf area index (LAI), precipitation, soil moisture, cloud cover, and vapor pressure deficit (VPD) in our analysis. Satellite-derived SIF observations provide a direct diagnosis of plant photosynthesis from space. The decomposition of SIF to SIF yield (SIFyield) and APAR (the product of PAR and fPAR) reveals the relative effects of precipitation and solar radiation on photosynthesis. We found that the drought significantly reduced SIFyield, the emitted SIF per photon absorbed. The higher APAR resulting from lower cloud cover and higher LAI partly offset the negative effects of water stress on the photosynthesis of Amazon forests, leading to a smaller reduction in SIF than in SIFyield and precipitation. We further found that SIFyield anomalies were more sensitive to precipitation and VPD anomalies in the southern regions of the Amazon than in the central and northern regions. Our findings shed light on the relative and combined effects of precipitation and solar radiation on photosynthesis, and can improve our understanding of the responses of Amazon forests to drought.

Reduced precipitation over large water bodies in the Brazilian Amazon shown from TRMM data

NASA Astrophysics Data System (ADS)

Paiva, Rodrigo Cauduro Dias; Buarque, Diogo Costa; Clarke, Robin T.; Collischonn, Walter; Allasia, Daniel Gustavo

2011-02-01

Tropical Rainfall Measurement Mission (TRMM) data show lower rainfall over large water bodies in the Brazilian Amazon. Mean annual rainfall (P), number of wet days (rainfall > 2 mm) (W) and annual rainfall accumulated over 3-hour time intervals (P3hr) were computed from TRMM 3B42 data for 1998-2009. Reduced rainfall was marked over the Rio Solimões/Amazon, along most Amazon tributaries and over the Balbina reservoir. In a smaller test area, a heuristic argument showed that P and W were reduced by 5% and 6.5% respectively. Allowing for TRMM 3B42 spatial resolution, the reduction may be locally greater. Analyses of diurnal rainfall patterns showed that rainfall is lowest over large rivers during the afternoon, when most rainfall is convective, but at night and early morning the opposite occurs, with increased rainfall over rivers, although this pattern is less marked. Rainfall patterns reported from studies of smaller Amazonian regions therefore exist more widely.

Monitoring of artificial water reservoirs in the Southern Brazilian Amazon with remote sensing data

NASA Astrophysics Data System (ADS)

Arvor, Damien; Daher, Felipe; Corpetti, Thomas; Laslier, Marianne; Dubreuil, Vincent

2016-10-01

The agricultural expansion in the Southern Brazilian Amazon has long been pointed out due to its severe impacts on tropical forests. But the last decade has been marked by a rapid agricultural transition which enabled to reduce pressure on forests through (i) the adoption of intensive agricultural practices and (ii) the diversification of activities. However, we suggest that this new agricultural model implies new pressures on environment and especially on water resources since many artificial water reservoirs have been built to ensure crop irrigation, generate energy, farm fishes, enable access to water for cattle or just for leisure. In this paper, we implemented a method to automatically map artificial water reservoirs based on time series of Landsat images. The method was tested in the county of Sorriso (State of Mato Grosso, Brazil) where we identified 521 water reservoirs by visual inspection on very high resolution images. 68 Landsat-8 images covering 4 scenes in 2015 were pre-classified and a final class (Terrestrial or Aquatic) was determined for each pixel based on a Dempster-Shafer fusion approach. Results confirmed the potential of the methodology to automatically and efficiently detect water reservoirs in the study area (overall accuracy = 0.952 and Kappa index = 0.904) although the methodology underestimates the total area in water bodies because of the spatial resolution of Landsat images. In the case of Sorriso, we mapped 19.4 km2 of the 20.8 km2 of water reservoirs initially delimited by visual interpretation, i.e. we underestimated the area by 5.9%.

Characterizing Temporal and Spatial Changes in Land Surface Temperature across the Amazon Basin using Thermal and Infrared Satellite Data

NASA Astrophysics Data System (ADS)

Cak, A. D.

2017-12-01

The Amazon Basin has faced innumerable pressures in recent years, including logging, mining and resource extraction, agricultural expansion, road building, and urbanization. These changes have drastically altered the landscape, transforming a predominantly forested environment into a mosaic of different types of land cover. The resulting fragmentation has caused dramatic and negative impacts on its structure and function, including on biodiversity and the transfer of water and energy to and from soil, vegetation, and the atmosphere (e.g., evapotranspiration). Because evapotranspiration from forested areas, which is affected by factors including temperature and water availability, plays a significant role in water dynamics in the Amazon Basin, measuring land surface temperature (LST) across the region can provide a dynamic assessment of hydrological, vegetation, and land use and land cover changes. It can also help to identify widespread urban development, which often has a higher LST signal relative to surrounding vegetation. Here, we discuss results from work to measure and identify drivers of change in LST across the entire Amazon Basin through analysis of past and current thermal and infrared satellite imagery. We leverage cloud computing resources in new ways to allow for more efficient analysis of imagery over the Amazon Basin across multiple years and multiple sensors. We also assess potential drivers of change in LST using spatial and multivariate statistical analyses with additional data sources of land cover, urban development, and demographics.

The impact of channel capture on estuarine hydro-morphodynamics and water quality in the Amazon delta.

PubMed

Silva Dos Santos, Eldo; Pinheiro Lopes, Paula Patrícia; da Silva Pereira, Hyrla Herondina; de Oliveira Nascimento, Otávio; Rennie, Colin David; da Silveira Lobo O'Reilly Sternberg, Leonel; Cavalcanti da Cunha, Alan

2018-05-15

Due to progressive erosion of the new Urucurituba Channel, the Amazon River has recently captured almost all discharge from the lower Araguari River (Amapá-AP, Brazil), which previously flowed directly to the Atlantic Ocean. These recent geomorphological changes have caused strong impacts on the landscape and hydrodynamic patterns near the Araguari River mouth, especially the alteration of the riverine drainage system and its water quality. Landsat images were used to assess the estuarine landscape morphodynamic, particularly the expansion of the Urucurituba Channel, 80km from the Araguari River mouth, chronicling its connection to the Amazon River. The results suggest that the Urucurituba developed by headward migration across the Amazon delta; this is perhaps the first observation of estuarine distributary network development by headward channel erosion. The rate of Urucurituba Channel width increase has been ≈5m/month since 2011, increasing drainage capacity of the channel. We also collected in situ hydrodynamic measurements and analyzed 17 water quality parameters. Having 2011 as baseline, the flowrate of Araguari River has been diverted by up to 98% through Urucurituba Channel, with substantial changes in net discharge recorded at 3 monitoring stations. Statistically significant differences in water quality (p<0.05) were observed between 2011 and 2015, associated with the change in the flow pattern. Estuarine salinity and solids concentrations have increased. Overall, we demonstrate changes in landscape, hydrodynamics and water quality of the lower Araguari River. Copyright © 2017 Elsevier B.V. All rights reserved.

AmazonFACE: Assessing the Effects of Increasing Atmospheric CO2 on the Resilience of the Amazon Forest through Integrative Model-Experiment Research

NASA Astrophysics Data System (ADS)

Lapola, D. M.

2015-12-01

The existence, magnitude and duration of a supposed "CO2 fertilization" effect in tropical forests remains largely undetermined, despite being suggested for nearly 20 years as a key knowledge gap for understanding the future resilience of Amazonian forests and its impact on the global carbon cycle. Reducing this uncertainty is critical for assessing the future of the Amazon region as well as its vulnerability to climate change. The AmazonFACE (Free-Air CO2 Enrichment) research program is an integrated model-experiment initiative of unprecedented scope in an old-growth Amazon forest near Manaus, Brazil - the first of its kind in tropical forest. The experimental treatment will simulate an atmospheric CO2 concentration [CO2] of the future in order to address the question: "How will rising atmospheric CO2 affect the resilience of the Amazon forest, the biodiversity it harbors, and the ecosystem services it provides, in light of projected climatic changes?" AmazonFACE is divided into three phases: (I) pre-experimental ecological characterization of the research site; (II) pilot experiment comprised of two 30-m diameter plots, with one treatment plot maintained at elevated [CO2] (ambient +200 ppmv), and the other control plot at ambient [CO2]; and (III) a fully-replicated long-term experiment comprised of four pairs of control/treatment FACE plots maintained for 10 years. A team of scientists from Brazil, USA, Australia and Europe will employ state-of-the-art methods to study the forest inside these plots in terms of carbon metabolism and cycling, water use, nutrient cycling, forest community composition, and interactions with environmental stressors. All project phases also encompass ecosystem-modeling activities in a way such that models provide hypothesis to be verified in the experiment, which in turn will feed models to ultimately produce more accurate projections of the environment. Resulting datasets and analyses will be a valuable resource for a broad community, especially ecosystem and climate modelers, and policy-makers.

The AmazonFACE research program: assessing the effects of increasing atmospheric CO2 on the ecology and resilience of the Amazon forest

NASA Astrophysics Data System (ADS)

Lapola, David; Quesada, Carlos; Norby, Richard; Araújo, Alessandro; Domingues, Tomas; Hartley, Iain; Kruijt, Bart; Lewin, Keith; Meir, Patrick; Ometto, Jean; Rammig, Anja

2016-04-01

The existence, magnitude and duration of a supposed "CO2 fertilization" effect in tropical forests remains largely undetermined, despite being suggested for nearly 20 years as a key knowledge gap for understanding the future resilience of Amazonian forests and its impact on the global carbon cycle. Reducing this uncertainty is critical for assessing the future of the Amazon region as well as its vulnerability to climate change. The AmazonFACE (Free-Air CO2 Enrichment) research program is an integrated model-experiment initiative of unprecedented scope in an old-growth Amazon forest near Manaus, Brazil - the first of its kind in tropical forest. The experimental treatment will simulate an atmospheric CO2 concentration [CO2] of the future in order to address the question: "How will rising atmospheric CO2 affect the resilience of the Amazon forest, the biodiversity it harbors, and the ecosystem services it provides, in light of projected climatic changes?" AmazonFACE is divided into three phases: (I) pre-experimental ecological characterization of the research site; (II) pilot experiment comprised of two 30-m diameter plots, with one treatment plot maintained at elevated [CO2] (ambient +200 ppmv), and the other control plot at ambient [CO2]; and (III) a fully-replicated long-term experiment comprised of four pairs of control/treatment FACE plots maintained for 10 years. A team of scientists from Brazil, USA, Australia and Europe will employ state-of-the-art methods to study the forest inside these plots in terms of carbon metabolism and cycling, water use, nutrient cycling, forest community composition, and interactions with environmental stressors. All project phases also encompass ecosystem-modeling activities in a way such that models provide hypothesis to be verified in the experiment, which in turn will feed models to ultimately produce more accurate projections of the environment. Resulting datasets and analyses will be a valuable resource for a broad community, especially ecosystem and climate modelers, and policy-makers.

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

NASA Technical Reports Server (NTRS)

Bosilovich, Michael G.; Chern, Jiun-Dar

2005-01-01

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

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

PubMed

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

2015-11-01

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

Public policies and communication affecting forest cover in the Amazon

NASA Astrophysics Data System (ADS)

Kawakami Savaget, E.; Batistella, M.; Aguiar, A. P. D.

2014-12-01

The research program Amazalert was based on information delivered by the IPCC through its 2007 report, which indicates forest degradation processes in the Amazonian region as a consequence of anthropogenic actions. Such processes affecting the structural and functional characteristics of ecosystems would harm environmental services that guarantee, for example, the regulation of climate and the provision of fresh water. A survey was organized, through a multidisciplinary perspective, on the main policies and programs that can affect forest cover in the Amazon. These rules and norms seek to regulate societal actions by defining a developmental model for the region. Although deforestation rates in the Brazilian Amazon have decreased significantly since 2004, some locations maintain high levels of deforestation. In 2013, for example, the municipalities of Monte Alegre, Óbidos, Alenquer, Oriximiná, Curuá and Almeirin, in the northern region of the state of Para, showed the highest rates of deforestation in the Amazon. Managers and stakeholders within these areas are being interviewed to provide insights on how policies are interpreted and applied locally. There is an understanding delay between discourses normalized by federal governmental institutions and claims of local societies. The possible lack of clarity in official discourses added to the absence of a local communicative dynamics cause the phenomenon of incomplete information. Conflicts often occur in local institutional arenas resulting in violence and complex social and historical dissonances, enhanced by other public policies idealized in different temporal and spatial conditions.

Manaus, Brazil

NASA Image and Video Library

2002-07-16

The junctions of the Amazon and the Rio Negro Rivers at Manaus, Brazil. The Rio Negro flows 2300 km from Columbia, and is the dark current forming the north side of the river. It gets its color from the high tannin content in the water. The Amazon is sediment laden, appearing brown in this simulated natural color image. Manaus is the capital of Amazonas state, and has a population in excess of one million. The ASTER image covers an area of 60 x 45 km. This image was acquired on July 16, 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet. http://photojournal.jpl.nasa.gov/catalog/PIA03851

Kudoa spp. (Myxozoa) infection in musculature of Plagioscion squamosissimus (Sciaenidae) in the Amazon region, Brazil.

PubMed

de Oliveira, Joyce Cardim; Velasco, Michele; dos Santos, Patrícia de Fátima Sacco; Silva, José Mauro Viana; Clemente, Sérgio Carmona de São; Matos, Edilson

2015-01-01

Ninety specimens of Plagioscion squamosissimus captured using fishing tackle in the Outeiro district, state of Pará, were examined. Fish were placed in plastic bags containing water, under conditions of artificial aeration, and transported live to the Carlos Azevedo Research Laboratory (LPCA), in Belém, Pará. They were anesthetized, euthanized and necropsied; small fragments of the epaxial and hypaxial muscles were removed for examination of fresh histological sections by means of optical microscopy. In 100% of the specimens analyzed, parasitic pseudocysts were seen to be interspersed within and between the skeletal muscle. These contained pseudoquadrate and/or star-shaped spores that presented four valves and four polar capsules, which were identified from their morphology as belonging to the genus Kudoa. This is the first report of Kudoa in P. squamosissimus in the Amazon region, Pará, Brazil.

Sources of water vapor to economically relevant regions in Amazonia and the effect of deforestation

NASA Astrophysics Data System (ADS)

Pires, G. F.; Fontes, V. C.

2017-12-01

The Amazon rain forest helps regulate the regional humid climate. Understanding the effects of Amazon deforestation is important to preserve not only the climate, but also economic activities that depend on it, in particular, agricultural productivity and hydropower generation. This study calculates the source of water vapor contributing to the precipitation on economically relevant regions in Amazonia according to different scenarios of deforestation. These regions include the state of Mato Grosso, which produces about 9% of the global soybean production, and the basins of the Xingu and Madeira, with infrastructure under construction that will be capable to generate 20% of the electrical energy produced in Brazil. The results show that changes in rainfall after deforestation are stronger in regions nearest to the ocean and indicate the importance of the continental water vapor source to the precipitation over southern Amazonia. In the two more continental regions (Madeira and Mato Grosso), decreases in the source of water vapor in one region were offset by increases in contributions from other continental regions, whereas in the Xingu basin, which is closer to the ocean, this mechanism did not occur. As a conclusion, the geographic location of the region is an important determinant of the resiliency of the regional climate to deforestation-induced regional climate change. The more continental the geographic location, the less climate changes after deforestation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Getirana, Augusto; Dutra, Emanuel; Guimberteau, Matthieu

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

Impact of Atmospheric Albedo on Amazon Evapotranspiration

NASA Astrophysics Data System (ADS)

Lopes, A. V.; Thompson, S. E.; Dracup, J. A.

2013-12-01

The vulnerability of the Amazon region to climate and anthropogenic driven disturbances has been the subject of extensive research efforts, given its importance in the global and regional climate and ecologic systems. The evaluation of such vulnerabilities requires the proper understanding of physical mechanisms controlling water and energy balances and how the disturbances change them. Among those mechanisms, the effects of atmospheric albedo on evapotranspiration have not been fully explored yet and are explored in this study. Evapotranspiration in the Amazon is sustained at high levels across all seasons and represents a large fraction of water and energy surface budgets. In this study, statistical analysis of data from four flux towers installed at Amazon primary forest sites was employed to quantify the impact of atmospheric albedo, mostly resulted from cloudiness, on evapotranspiration and to compare it to the effect of water limitation. Firstly, the difference in eddy-flux derived evapotranspiration at the flux towers under rainy and non-rainy antecedent conditions was tested for significance. Secondly, the same statistical comparison was performed under cloudy and clear sky conditions at hourly and daily time scales, using the reduction in incoming solar radiation as an indicator of cloudiness. Finally, the sensitivity of seasonal evapotranspiration totals to atmospheric albedo resulted from rainfall patterns is evaluated. That was done by sampling daily evapotranspiration estimates from empirical probability distribution functions conditioned to rainfall occurrence and then varying the number of dry days in each season. It was found that light limitation is much more important than water limitation in the Amazon, resulting in up to 43% reduction in daily evapotranspiration. Also, this effect varies by location and by season, the largest impact being in wet season, from December do January. Moreover, seasonal evapotranspiration totals were found to be highly sensitive to the duration of dry spells, set by rainfall patterns, especially during wet seasons and further South from the Equator. These results points to the importance of proper understanding of convective systems and their effects on atmospheric albedo in assessing the vulnerability of Amazon basins to extended dry periods.

Monitoring stress-related mass variations in Amazon trees using accelerometers

NASA Astrophysics Data System (ADS)

van Emmerik, T. H. M.; Steele-Dunne, S. C.; Gentine, P.; Hut, R.; Guerin, M. F.; Leus, G.; Oliveira, R. S.; Van De Giesen, N.

2016-12-01

Containing half of the world's rainforests, the Amazon plays a key role in the global water and carbon budget. However, the Amazon remains poorly understood, but appears to be vulnerable to increasing moisture stress, and future droughts have the potential to considerably change the global water and carbon budget. Field measurements will allow further investigations of the effects of moisture stress and droughts on tree dynamics, and its impact on the water and carbon budget. This study focuses on studying the diurnal mass variations of seven Amazonian tree species. The mass of trees is influenced by physiological processes within the tree (e.g. transpiration and root water uptake), as well as external loads (e.g. intercepted precipitation). Depending on the physiological traits of an individual tree, moisture stress and drought affect processes such as photosynthesis, assimilation, transpiration, and root water uptake. In turn, these have their influence on diurnal mass variations of a tree. Our study uses measured three-dimensional displacement and acceleration of trees, to detect and quantify their diurnal (bio)mass variations. Nineteen accelerometers and dendrometers were installed on seven different tree species in the Amazon rainforest, covering an area of 250 x 250 m. The selected species span a wide range in wood density (0.5 - 1.1), diameter (15 - 40 cm) and height (25 - 60 m). Acceleration was measured with a frequency of 10 Hz, from August 2015 to June 2016, covering both the wet and dry season. On-site additional measurements of net radiation, wind speed at three heights, temperature, and precipitation as available every 15 minutes. Dendrometers measured variation in xylem and bark thickness every 5 minutes. The MUltiple SIgnal Classification (MUSIC) algorithm was applied to the acceleration time series to estimate the frequency spectrum of each tree. A correction was necessary to account for the dominant effect of wind. The resulting spectra reveal clear diurnal variations, as well as changes during precipitation events. Comparison with ancillary data suggests that we can extract information on diurnal mass variations from the accelerometer data. This may provide valuable insight into the effects of water stress on mass variations in different Amazon tree species.

Palms versus trees: water use characteristics of native fruit-bearing plant species in the Central Amazon

NASA Astrophysics Data System (ADS)

Kunert, N.; Barros, P.; Higuchi, N.

2012-12-01

Native fruiting plants are widely cultivated in the Amazon but only little information on their water use characteristics can be found in the literature. Due to the growing local consumption and the increasing popularity for new "exotic" fruits all over Brazil and worldwide, additional new plantations cultivating such fruit-bearing species might be established in the Amazon in the future. These new plantations will affect the water table of the cultivated areas, however, the impact of these changes on the regional hydrology are not known. We, therefore, decided to study plant water use characteristics of two native fruit plants commonly occurring in the Amazon region, a tree species (Cupuaçu, Theobroma grandiflorum, (Willd. ex Spreng.) Schum., Malvaceae) and a palm species (Açai, Euterpe oleraceae Mart., Arecaceae). This study was conducted in a fruit plantation close to the city of Manaus, in the Central Amazon, Brazil. The objectives of our study were 1) to compare variables controlling plant water use and 2) to identify differences in water use between woody monocot and dicot plant species. We chose three representative individuals with well-sun-exposed crowns for each species, which were equipped with Granier-type thermal dissipation probes to measure sap flux density continuously for six weeks from August 1st 2011 until September 6th 2011. We used a simple sap flux model with two environmental variables, photosynthetic photon flux density and vapor pressure deficit, to compare sap flux densities between species. We achieved a good model fit and modeled sap flux densities corresponded very well with the actual measured values. No significant differences among species in sap flux densities were indicated by the model. Overall, palms had a 3.5 fold higher water consumption compared to trees with similar diameter. Water use scaled independent from species with the size of the conductive xylem area (r2 = 0.85), so that the higher water use of the palms was largely explained by higher conductivity of the xylem cross section area. Palms transpired a mean of 1.67 mm m-2 of water per unit crown projection area per day, whereas trees transpired only 0.30 mm m-2 per day, resulting in a 5.6 times lower transpiration rate. We conclude that changes in the water table due to land use change are predictable and highly depending on the species planted in the area with altered land use.

A review of green- and blue-water resources and their trade-offs for future agricultural production in the Amazon Basin: what could irrigated agriculture mean for Amazonia?

NASA Astrophysics Data System (ADS)

Lathuillière, Michael J.; Coe, Michael T.; Johnson, Mark S.

2016-06-01

The Amazon Basin is a region of global importance for the carbon and hydrological cycles, a biodiversity hotspot, and a potential centre for future economic development. The region is also a major source of water vapour recycled into continental precipitation through evapotranspiration processes. This review applies an ecohydrological approach to Amazonia's water cycle by looking at contributions of water resources in the context of future agricultural production. At present, agriculture in the region is primarily rain-fed and relies almost exclusively on green-water resources (soil moisture regenerated by precipitation). Future agricultural development, however, will likely follow pathways that include irrigation from blue-water sources (surface water and groundwater) as insurance from variability in precipitation. In this review, we first provide an updated summary of the green-blue ecohydrological framework before describing past trends in Amazonia's water resources within the context of land use and land cover change. We then describe green- and blue-water trade-offs in light of future agricultural production and potential irrigation to assess costs and benefits to terrestrial ecosystems, particularly land and biodiversity protection, and regional precipitation recycling. Management of green water is needed, particularly at the agricultural frontier located in the headwaters of major tributaries to the Amazon River, and home to key downstream blue-water users and ecosystem services, including domestic and industrial users, as well as aquatic ecosystems.

Campaign datasets for Observations and Modeling of the Green Ocean Amazon (GOAMAZON)

DOE Data Explorer

Martin,Scot; Mei,Fan; Alexander,Lizabeth; Artaxo,Paulo; Barbosa,Henrique; Bartholomew,Mary Jane; Biscaro,Thiago; Buseck,Peter; Chand,Duli; Comstock,Jennifer; Dubey,Manvendra; Godstein,Allen; Guenther,Alex; Hubbe,John; Jardine,Kolby; Jimenez,Jose-Luis; Kim,Saewung; Kuang,Chongai; Laskin,Alexander; Long,Chuck; Paralovo,Sarah; Petaja,Tuukka; Powers,Heath; Schumacher,Courtney; Sedlacek,Arthur; Senum,Gunnar; Smith,James; Shilling,John; Springston,Stephen; Thayer,Mitchell; Tomlinson,Jason; Wang,Jian; Xie,Shaocheng

2016-05-30

The hydrologic cycle of the Amazon Basin is one of the primary heat engines of the Southern Hemisphere. Any accurate climate model must succeed in a good description of the Basin, both in its natural state and in states perturbed by regional and global human activities. At the present time, however, tropical deep convection in a natural state is poorly understood and modeled, with insufficient observational data sets for model constraint. Furthermore, future climate scenarios resulting from human activities globally show the possible drying and the eventual possible conversion of rain forest to savanna in response to global climate change. Based on our current state of knowledge, the governing conditions of this catastrophic change are not defined. Human activities locally, including the economic development activities that are growing the population and the industry within the Basin, also have the potential to shift regional climate, most immediately by an increment in aerosol number and mass concentrations, and the shift is across the range of values to which cloud properties are most sensitive. The ARM Climate Research Facility in the Amazon Basin seeks to understand aerosol and cloud life cycles, particularly the susceptibility to cloud aerosol precipitation interactions, within the Amazon Basin.

Palm Swamp Wetland Ecosystems of the Upper Amazon: Characterizing their Distribution and Inundation State Using Multiple Resolution Microwave Remote Sensing

NASA Astrophysics Data System (ADS)

Podest, E.; McDonald, K. C.; Schröder, R.; Pinto, N.; Zimmermann, R.; Horna, V.

2011-12-01

Palm swamp wetlands are prevalent in the Amazon basin, including extensive regions in northern Peru. These ecosystems are characterized by constant surface inundation and moderate seasonal water level variation. The combination of constantly saturated soils, giving rise to low oxygen conditions, and warm temperatures year-round can lead to considerable methane release to the atmosphere. Because of the widespread occurrence and expected sensitivity of these ecosystems to climate change, knowledge of their spatial extent and inundation state is crucial for assessing the associated land-atmosphere carbon exchange. Precise spatio-temporal information on palm swamps is difficult to gather because of their remoteness and difficult accessibility. Spaceborne microwave remote sensing is an effective tool for characterizing these ecosystems since it is sensitive to surface water and vegetation structure and allows monitoring large inaccessible areas on a temporal basis regardless of atmospheric conditions or solar illumination. We are developing a remote sensing methodology using multiple resolution microwave remote sensing data to determine palm swamp distribution and inundation state over focus regions in the Amazon basin in northern Peru. For this purpose, two types of multi-temporal microwave data are used: 1) high-resolution (100 m) data from the Advanced Land Observing Satellite (ALOS) Phased Array L-Band Synthetic Aperture Radar (PALSAR) to derive maps of palm swamp extent and inundation from dual-polarization fine-beam and multi-temporal HH-polarized ScanSAR, and 2) coarse resolution (25 km) combined active and passive microwave data from QuikSCAT and AMSR-E to derive inundated area fraction on a weekly basis. We compare information content and accuracy of the coarse resolution products to the PALSAR-based datasets to ensure information harmonization. The synergistic combination of high and low resolution datasets will allow for characterization of palm swamps and assessment of their flooding status. This work has been undertaken partly within the framework of the JAXA ALOS Kyoto & Carbon Initiative. PALSAR data have been provided by JAXA/EORC. Portions of this work were carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Estimation of precipitable water over the Amazon Basin using GOES imagery

NASA Astrophysics Data System (ADS)

Callahan, John Andrew

The Amazon Rainforest is the largest continuous rainforest on Earth. It holds a rich abundance of life containing approximately one-half of all existing plant and animal species and 20% of the world's fresh water. Climatologically, the Amazon Rainforest is a massive storehouse of carbon dioxide and water vapor and hosts hydrologic and energy cycles that influence regional and global patterns. However, this region has gone through vast land cover changes during the past several decades. Lack of conventional, in situ data sources prohibits detailed measurements to assess the climatological impact these changes may cause. This thesis applies a satellite-based, thermal infrared remote sensing algorithm to determine precipitable water in the Amazon Basin to test its applicability in the region and to measure the diurnal changes in water vapor. Imagery from the GOES geostationary satellite and estimated atmospheric conditions and radiance values derived from the NCEP/NCAR Reanalysis project were used as inputs to the Physical Split Window (PSW) technique. Retrievals of precipitable water were made every 3 hours throughout each day from 12Z to 24Z for the months of June and October, 1988 and 1995. These months correspond to when the atmosphere is not dominated by clouds during the rainy (wet) season or smoke and haze during the burning (dry) season. Monthly, daily, and diurnal aggregates of precipitable water Fields were analyzed spatially through seven zones located uniformly throughout the region. Monthly average precipitable water values were found to be 20mm to 25mm in the southeast and 45mm to 50mm in the northwest zones. Central and northwest zones showed little variation throughout the day with most areas peaking between 15Z and 21Z, representing early to late afternoon local time. Comparisons were made to nearby, coincident radiosonde observations with r ranging from 0.7 to 0.9 and MAE from 6mm to 12 mm.

Amazon Forest Responses to Drought and Fire

NASA Astrophysics Data System (ADS)

Morton, D. C.

2015-12-01

Deforestation and agricultural land uses provide a consistent source of ignitions along the Amazon frontier during the dry season. The risk of understory fires in Amazon forests is amplified by drought conditions, when fires at the forest edge may spread for weeks before rains begin. Fire activity also impacts the regional response of intact forests to drought through diffuse light effects and nutrient redistribution, highlighting the complexity of feedbacks in this coupled human and natural system. This talk will focus on recent advances in our understanding of fire-climate feedbacks in the Amazon, building on research themes initiated under NASA's Large-scale Biosphere-Atmosphere Experiment in Amazonia (LBA). NASA's LBA program began in the wake of the 1997-1998 El Niño, a strong event that exposed the vulnerability of Amazon forests to drought and fire under current climate and projections of climate change. With forecasts of another strong El Niño event in 2015-2016, this talk will provide a multi-scale synthesis of Amazon forest responses to drought and fire based on field measurements, airborne lidar data, and satellite observations of fires, rainfall, and terrestrial water storage. These studies offer new insights into the mechanisms governing fire season severity in the southern Amazon and regional variability in carbon losses from understory fires. The contributions from remote sensing to our understanding of drought and fire in Amazon forests reflect the legacy of NASA's LBA program and the sustained commitment to interdisciplinary research across the Amazon region.

Late Quaternary paleohydrology deduced from new marine sediment cores taken on the proximal Amazon continental margin

NASA Astrophysics Data System (ADS)

Nace, T.; Baker, P. A.; Dwyer, G. S.; Hollander, D. J.; Silva, C. G.

2010-12-01

Throughout the late Quaternary the Amazon Basin has been influenced by abrupt North-South climate forcing and has undergone several large climate variations as recorded in previously reported speleothem records. Despite its importance in the global carbon cycle there are few continuous, high-resolution records of the Amazon Basin that date back to and beyond the last glacial period. In this study, we report the first results of a marine geological expedition to the Amazon continental shelf and fan region. During this expedition we collected eight ~30 meter piston cores along with gravity, box and multicores. At both sites we undertook complementary multibeam and high resolution seismic reflection profiling. Analyses will be presented from two sets of box/gravity/piston cores. One core (32m) is from a high sedimentation site on the northern flank of the main submarine canyon within the Amazon Fan complex at 1700m water depth. The other core (30m) is located on a seamount to the south of the Amazon Fan complex at 3100m water depth. A mixed assemblage of foraminifera is used for 14C dating to obtain an age model and bulk organic geochemistry is analyzed to determine percent organic carbon, C/N ratios, δ13C and δ15N. The cores were continuously measured shipboard for magnetic susceptibility and gamma density using a GEOTEK logger. These findings uncover the contribution of pelagic and terrestrial organic matter, whether the terrigenous carbon is derived from C3 versus C4 vegetation, and whether the marine organic matter is composed of phytoplankton or marine algae.

Amazon water lenses and the influence of the North Brazil Current on the continental shelf

NASA Astrophysics Data System (ADS)

Prestes, Yuri O.; Silva, Alex Costa da; Jeandel, Catherine

2018-05-01

The exchange processes on the Amazon continental shelf in northern Brazil are subject to complex interactions that involve forcings derived from distinct sources. The Amazon shelf is a unique and highly dynamic environment in which considerable discharge of freshwater enters the Atlantic Ocean, producing extensive Amazon Water Lenses (AWL). In addition to the presence of the AWL, the shelf is influenced by the semidiurnal oscillations of the tides and the strong North Brazil Current (NBC), a boundary current of the western Atlantic. The present study was based primarily on the influence of the freshwater input and the NBC on the shelf and the Amazon Shelf Break (ASB) off the mouth of the Pará River. For this purpose, hydrographic and hydrodynamic data were obtained by moorings of the AMANDES Project (April-July 2008), located on the Amazon shelf and the ASB. Spectral analysis and the continuous wavelet transform were applied to define tidal (high frequency/short period) and subtidal (low frequency/long period) signals. The results indicated that on both the shelf and the break, the semidiurnal tides are responsible for the residual landward transport and are predominantly across-shelf. Low-frequency motions in the synoptic bands and the AWL are related to spatial changes in the velocity field, mainly on the ASB in the along-shelf direction. The flow of the NBC can be interpreted as an along-shelf low-frequency oscillation capable of altering the spatial configuration of the velocity field, although its influence is perceived only in the absence of the AWL.

Living Rivers: Importance of Andes-Amazon Connectivity and Consequences of Hydropower Development

NASA Astrophysics Data System (ADS)

Anderson, E.

2016-12-01

The inherent dynamism of rivers along elevational and longitudinal gradients underpins freshwater biodiversity, ecosystem function, and ecosystem services in the Andean-Amazon. While this region covers only a small part of the entire Amazon Basin, its influences on downstream ecology, biogeochemistry, and human wellbeing are disproportionate with its relative small size. Seasonal flow pulses from Andean rivers maintain habitat, signal migratory fishes, and export sediment, nutrients, and organic matter to distant ecosystems—like lowland Amazonia and the Atlantic coast of Brazil. Rivers are key transportation routes, and freshwater fisheries are a primary protein source for the >30 million people that inhabit the Amazon Basin. Numerous cultural traditions depend on free-flowing Andean rivers; examples include Kukama beliefs in the underwater cities of the Marañon River, where people who have drowned in rivers whose bodies are not recovered go to live, or the pre-dawn bathing rituals of the Peruvian Shawi, who gain energy and connect with ancestors in cold, fast-flowing Andean waters. Transformations in the Andean-Amazon landscape—in particular from dams—threaten to compromise flows critical for human and ecosystem wellbeing. Presently, at least 250 hydropower dams are in operation, under construction, or proposed for Andean-Amazon rivers. This presentation will discuss regional trends in hydropower development, quantify effects of existing and proposed dams on Andean-Amazon connectivity, and examine the social and cultural importance of free-flowing Andean-Amazon rivers.

Input of particulate organic and dissolved inorganic carbon from the Amazon to the Atlantic Ocean

NASA Astrophysics Data System (ADS)

Druffel, E. R. M.; Bauer, J. E.; Griffin, S.

2005-03-01

We report concentrations and isotope measurements (radiocarbon and stable carbon) of dissolved inorganic carbon (DIC) and suspended particulate organic carbon (POC) in waters collected from the mouth of the Amazon River and the North Brazil Current. Samples were collected in November 1991, when the Amazon hydrograph was at its annual minimum and the North Brazil Current had retroflected into the equatorial North Atlantic. The DIC Δ14C results revealed postbomb carbon in river and ocean waters, with slightly higher values at the river mouth. The low DIC δ13C signature of the river end-member (-11‰) demonstrates that about half of the DIC originated from the remineralization of terrestrially derived organic matter. A linear relationship between DIC and salinity indicates that DIC was mixed nearly conservatively in the transition zone from the river mouth to the open ocean, though there was a small amount (≤10%) of organic matter remineralization in the mesohaline region. The POC Δ14C values in the river mouth were markedly lower than those values from the western Amazon region (Hedges et al., 1986). We conclude that the dominant source of POC near the river mouth and in the inner Amazon plume during November 1991 was aged, resuspended material of significant terrestrial character derived from shelf sediments, while the outer plume contained mainly marine-derived POC.

Characterization of Particle Backscattering of Global Highly Turbid Waters From VIIRS Ocean Color Observations

NASA Astrophysics Data System (ADS)

Shi, Wei; Wang, Menghua

2017-11-01

Normalized water-leaving radiance spectra nLw(λ) at the near-infrared (NIR) from five years of observations (2012-2016) with the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (SNPP) are used to derive the particle backscattering coefficients bbp(λ) for global highly turbid coastal and inland waters. Based on the fact that the absorption coefficient of sea water aw(λ) is generally much larger than those of the other constituents aiop(λ) at the NIR wavelengths in coastal and inland waters, an NIR-based bbp(λ) algorithm for turbid coastal and inland waters has been developed and used in this study. This algorithm can be safely used for highly turbid waters with nLw(745) and nLw(862) < ˜6 and ˜4 mW cm-2 μm-1 sr-1, respectively. Seasonal and interannual variations of bbp(λ) in China's east coastal region, the Amazon River Estuary, the La Plata River Estuary, the Meghna River Estuary, the Atchafalaya River Estuary, and Lake Taihu are characterized and quantified. The coefficient bbp(λ) can reach over ˜3-4 m-1 in the Amazon River Estuary and China's east coastal region. The Amazon River Estuary is identified as the most turbid region in the global ocean in terms of bbp(λ) magnitude. bbp(λ) spectra in these five highly turbid regions are also seasonal-dependent and regional-dependent. In the highly turbid waters of China's east coastal region and the Amazon River Estuary, bbp(λ) generally increases in wavelength from 410 to 862 nm, while it decreases in the La Plata River Estuary and Atchafalaya River Estuary. This is attributed to the different particle size distributions in these waters. The geophysical implication of the bbp(λ) spectral curvatures for different waters is discussed. To improve global bbp(λ) for both open oceans and coastal turbid waters, a new combined NIR-based and Quasi-Analytical Algorithm (QAA)-based bbp(λ) algorithm is proposed and demonstrated.

Damming the rivers of the Amazon basin

NASA Astrophysics Data System (ADS)

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

2017-06-01

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

Damming the rivers of the Amazon basin.

PubMed

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

2017-06-14

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

A direct estimate of evapotranspiration over the Amazon basin and implications for our understanding of carbon and water cycling

NASA Astrophysics Data System (ADS)

Swann, A. L. S.; Koven, C.; Lombardozzi, D.; Bonan, G. B.

2017-12-01

Evapotranspiration (ET) is a critical term in the surface energy budget as well as the water cycle. There are few direct measurements of ET, and thus the magnitude and variability is poorly constrained at large spatial scales. Estimates of the annual cycle of ET over the Amazon are critical because they influence predictions of the seasonal cycle of carbon fluxes, as well as atmospheric dynamics and circulation. We estimate ET for the Amazon basin using a water budget approach, by differencing rainfall, discharge, and time-varying storage from the Gravity Recovery and Climate Experiment. We find that the climatological annual cycle of ET over the Amazon basin upstream of Óbidos shows suppression of ET during the wet season, and higher ET during the dry season, consistent with flux tower based observations in seasonally dry forests. We also find a statistically significant decrease in ET over the time period 2002-2015 of -1.46 mm/yr. Our direct estimate of the seasonal cycle of ET is largely consistent with previous indirect estimates, including energy budget based approaches, an up-scaled station based estimate, and land surface model estimates, but suggests that suppression of ET during the wet season is underestimated by existing products. We further quantify possible contributors to the phasing of the seasonal cycle and downward time trend using land surface models.

Using surface displacement derived from GRACE to constrain the water loading signal in cGPS measurements in the Amazon Basin

NASA Astrophysics Data System (ADS)

Jose, L.; Bennett, R. A.; Harig, C.

2017-12-01

Currently, cGPS data is well suited to track vertical changes in the Earth's surface. However, there are annual, semi-annual, and interannual signals within cGPS time series that are not well constrained. We hypothesize that these signals are primarily due to water loading. If this is the case, the conventional method of modeling cGPS data as an annual or semiannual sinusoid falls short, as such models cannot accurately capture all variations in surface displacement, especially those due to extreme hydrologic events. We believe that we can better correct the cGPS time series with another method we are developing wherein we use a time series of surface displacement derived from the GRACE geopotential field instead of a sinusoidal model to correct the data. Currently, our analysis is constrained to the Amazon Basin, where the signal due to water loading is large enough to appear in both the GRACE and cGPS measurements. The vertical signal from cGPS stations across the Amazon Basin show an apparent spatial correlation, which further supports our idea that these signals are due to a regional water loading signal. In our preliminary research, we used tsview for Matlab to find that the WRMS of the corrected cGPS time series can be reduced as much as 30% from the model corrected data to the GRACE corrected data. The Amazon, like many places around the world, has experienced extreme drought, in 2005, 2010, and recently in 2015. In addition to making the cGPS vertical signal more robust, the method we are developing has the potential to help us understand the effects of these weather events and track trends in water loading.

Observations of atmospheric monoaromatic hydrocarbons at urban, semi-urban and forest environments in the Amazon region

NASA Astrophysics Data System (ADS)

Paralovo, Sarah L.; Borillo, Guilherme C.; Barbosa, Cybelli G. G.; Godoi, Ana Flavia L.; Yamamoto, Carlos I.; de Souza, Rodrigo A. F.; Andreoli, Rita V.; Costa, Patrícia S.; Almeida, Gerson P.; Manzi, Antonio O.; Pöhlker, Christopher; Yáñez-Serrano, Ana M.; Kesselmeier, Jürgen; Godoi, Ricardo H. M.

2016-03-01

The Amazon region is one of the most significant natural ecosystems on the planet. Of special interest as a major study area is the interface between the forest and Manaus city, a state capital in Brazil embedded in the heart of the Amazon forest. In view of the interactions between natural and anthropogenic processes, an integrated experiment was conducted measuring the concentrations of the volatile organic compounds (VOCs) benzene, toluene, ethylbenzene and meta, ortho, para-xylene (known as BTEX), all of them regarded as pollutants with harmful effects on human health and vegetation and acting also as important precursors of tropospheric ozone. Furthermore, these compounds also take part in the formation of secondary organic aerosols, which can influence the pattern of cloud formation, and thus the regional water cycle and climate. The samples were collected in 2012/2013 at three different sites: (i) The Amazon Tall Tower Observatory (ATTO), a pristine rain forest region in the central Amazon Basin; (ii) Manacapuru, a semi-urban site located southwest and downwind of Manaus as a preview of the Green Ocean Amazon Experiment (GoAmazon 2014/15); and (iii) the city of Manaus (distributed over three sites). Results indicate that there is an increase in pollutant concentrations with increasing proximity to urban areas. For instance, the benzene concentration ranges were 0.237-19.6 (Manaus), 0.036-0.948 (Manacapuru) and 0.018-0.313 μg m-3 (ATTO). Toluene ranges were 0.700-832 (Manaus), 0.091-2.75 μg m-3 (Manacapuru) and 0.011-4.93 (ATTO). For ethylbenzene, they were 0.165-447 (Manaus), 0.018-1.20 μg m-3 (Manacapuru) and 0.047-0.401 (ATTO). Some indication was found for toluene to be released from the forest. No significant difference was found between the BTEX levels measured in the dry season and the wet seasons. Furthermore, it was observed that, in general, the city of Manaus seems to be less impacted by these pollutants than other cities in Brazil and in other countries, near the coastline or on the continent. A risk analysis for the health of Manaus' population was performed and indicated that the measured concentrations posed a risk for development of chronic diseases and cancer for the population of Manaus.

Using Innovative Knowledge Management Tools for Information Technology Development, Acquisition, and Integration in the United States Army

DTIC Science & Technology

2007-06-15

Jeff Bezos , at Jeff @Amazon.com. Ultimately, this exchange produced no verification of the information I was able to garner from the Internet, to...that conventional brick-and-mortar and mail-order bookstores could. Jeff Bezos , President, Chief Executive Officer and Chairman of the Board...was aptly chosen and has truly become synonymous with voluminous Amazon River. Jeff Bezos , Amazon.com President and CEO, changed the name from

Role of the floodplain lakes in the methylmercury distribution and exchanges with the Amazon River, Brazil.

PubMed

Maia, Poliana Dutra; Maurice, Laurence; Tessier, Emmanuel; Amouroux, David; Cossa, Daniel; Moreira-Turcq, Patricia; Etcheber, Henri

2018-06-01

Seasonal variability of dissolved and particulate methylmercury (F-MeHg, P-MeHg) concentrations was studied in the waters of the Amazon River and its associated Curuai floodplain during hydrological year 2005-2006, to understand the MeHg exchanges between these aquatic systems. In the oxic white water lakes, with neutral pH, high F-MeHg and P-MeHg concentrations were measured during the rising water stage (0.70±0.37pmol/L, n=26) and flood peak (14.19±9.32pmol/g, n=7) respectively, when the Amazon River water discharge into the lakes was at its maximum. The lowest mean values were reported during the dry season (0.18±0.07pmol/L F-MeHg, n=10 and 1.35±1.24pmol/g P-MeHg, n=8), when water and suspended sediments were outflowing from the lakes into the River. In these lakes, the MeHg concentrations were associated to the aluminium and organic carbon/nitrogen changes. In the black water lakes, with acidic pH and reducing conditions, elevated MeHg concentrations were recorded (0.58±0.32pmol/L F-MeHg, n=16 and 19.82±15.13pmol/g P-MeHg, n=6), and correlated with the organic carbon and manganese concentrations. Elevated values of MeHg partition coefficient (4.87

Methane emissions to the troposphere from the Amazon floodplain

NASA Technical Reports Server (NTRS)

Devol, Allen H.; Richey, Jeffrey E.; Clark, Wayne A.; King, Stagg L.; Martinelli, Luiz A.

1988-01-01

The magnitudes of CH4 emissions to the troposphere from the Amazon River floodplain and the mechanism of these emissions were investigated using the data of 94 individual flux measurements made along a 1700-km stretch of the river during July/August 1985. The overall average rate of CH4 emission from wetlands was found to be 390 mg CH4/sq m per day, with the highest emissions (590 mg CH4/sq m per day) attributed to the water surfaces covered by aquatic macrophytes. Ebullition was the dominant mechanism of emission, accounting for 85 percent of the total. Surface-water CH4 concentrations were highly supersaturated, averaging 6.4 micromolar. The annual emission of CH4 from the Amazon Basin to the troposphere, estimated from the area and the known emission rate, is about 10 CH4 Tg/yr, indicating the importance of the area in the global atmospheric CH4 cycle.

Backwater effects in the Amazon River basin of Brazil

USGS Publications Warehouse

Meade, R.H.; Rayol, J.M.; Da Conceicao, S.C.; Natividade, J.R.G.

1991-01-01

The Amazon River mainstem of Brazil is so regulated by differences in the timing of tributary inputs and by seasonal storage of water on floodplains that maximum discharges exceed minimum discharges by a factor of only 3. Large tributaries that drain the southern Amazon River basin reach their peak discharges two months earlier than does the mainstem. The resulting backwater in the lowermost 800 km of two large southern tributaries, the Madeira and Puru??s rivers, causes falling river stages to be as much as 2-3 m higher than rising stages at any given discharge. Large tributaries that drain the northernmost Amazon River basin reach their annual minimum discharges three to four months later than does the mainstem. In the lowermost 300-400 km of the Negro River, the largest northern tributary and the fifth largest river in the world, the lowest stages of the year correspond to those of the Amazon River mainstem rather than to those in the upstream reaches of the Negro River. ?? 1991 Springer-Verlag New York Inc.

Effects of Land Use Changes on the Water and Energy Balance Over South America

NASA Astrophysics Data System (ADS)

Nascimento, M.; Herdies, D. L.; Angelis, C.

2013-05-01

With the objective of analyzing the effects of land use changes in the Amazon and its consequences on the main components of the water and energy balance over South America, with emphasis on the Amazon and La Plata Basin, two experiments were carried for 10-year period (1999-2008), in which the land use conditions were modified, representing conditions for the 90s (CONTROL Experiment) and current conditions over land use in the Amazon region (Experiment 1). Changes in land use were observed mainly in the Amazon region and southern Brazil. The numerical model used to perform the simulations was the ETA in its climate version, using as an initial and boundary condition the CFSR/NCEP reanalysis datasets. The results show for the analyzed period that there was a reduction of 3.3 mm/month in average rainfall rates in the La Plata Basin and 4.2 mm/month in the Amazon region, with some places where this reduction was more pronounced. Seasonally was observed that during the summer there is an average reduction of 3.9 mm/month in the Amazon region. Already on the La Plata Basin was observed an average increase of 11.7 mm/month in the La Plata Basin during the summer and an reduction in winter season. Through the overall result was also possible to conclude that the changes in land use for more realistic conditions, there were significant reductions in evapotranspiration and latent heat fluxes, as well as an increase in sensible heat fluxes, especially over the regions where the changes were more pronounced. Through the analyzes it can be observed that in general the La Plata Basin is sensitive to changes in land use over the Amazon and adjacent regions, allowing to conclude that such changes can influence the amount of rainfall, the intensity of the major meteorological systems, as well as temperature trends on the regions analyzed.

MODELING THE EFFECTS OF CLIMATE AND LAND USE CHANGE ON CARBON AND TRACE GAS BUDGETS OVER THE AMAZON REGION USING NASA SATELLITE PRODUCTS

EPA Science Inventory

As part of the LBA-ECO Phase III synthesis efforts for remote sensing and predictive modeling of Amazon carbon, water, and trace gas fluxes, we are evaluating results from the regional ecosystem model called NASA-CASA (Carnegie-Ames Stanford Approach). The NASA-CASA model has bee...

2004 Environment Industry

DTIC Science & Technology

2004-01-01

the country of greatest concern in the region, has put under government protection 10% of the Amazon region, created a national water resources policy...activity. The desire for basic human security often outweighs concern about environmental impact. Logging in the Amazon region, for example, is necessary...Conservation International and the Rainforest Action Network. Now that local groups are receiving more recognition from their own governments, the

Oxidative mitigation of aquatic methane emissions in large Amazonian rivers.

PubMed

Sawakuchi, Henrique O; Bastviken, David; Sawakuchi, André O; Ward, Nicholas D; Borges, Clovis D; Tsai, Siu M; Richey, Jeffrey E; Ballester, Maria Victoria R; Krusche, Alex V

2016-03-01

The flux of methane (CH4 ) from inland waters to the atmosphere has a profound impact on global atmospheric greenhouse gas (GHG) levels, and yet, strikingly little is known about the dynamics controlling sources and sinks of CH4 in the aquatic setting. Here, we examine the cycling and flux of CH4 in six large rivers in the Amazon basin, including the Amazon River. Based on stable isotopic mass balances of CH4 , inputs and outputs to the water column were estimated. We determined that ecosystem methane oxidation (MOX) reduced the diffusive flux of CH4 by approximately 28-96% and varied depending on hydrologic regime and general geochemical characteristics of tributaries of the Amazon River. For example, the relative amount of MOX was maximal during high water in black and white water rivers and minimal in clear water rivers during low water. The abundance of genetic markers for methane-oxidizing bacteria (pmoA) was positively correlated with enhanced signals of oxidation, providing independent support for the detected MOX patterns. The results indicate that MOX in large Amazonian rivers can consume from 0.45 to 2.07 Tg CH4 yr(-1) , representing up to 7% of the estimated global soil sink. Nevertheless, climate change and changes in hydrology, for example, due to construction of dams, can alter this balance, influencing CH4 emissions to atmosphere. © 2015 John Wiley & Sons Ltd.

Seroprevalence of Toxoplasma gondii antibodies in humans from rural Western Amazon, Brazil.

PubMed

Cavalcante, G T; Aguilar, D M; Camargo, L M A; Labruna, M B; de Andrade, H F; Meireles, L R; Dubey, J P; Thulliez, P; Dias, R A; Gennari, S M

2006-06-01

Antibodies to Toxoplasma gondii were assayed in sera of 266 humans from 71 farms located at Rondônia State, Western Amazon, Brazil, by the modified agglutination test (MAT) and the indirect immunofluorescent antibody test (IFAT). Antibodies were found in 195 humans (73.3%), with MAT titers of 1:25 in 11, 1:50 in 11, 1:100 in 16, 1:200 in 27, 1:400 in 38, 1:800 in 37, 1:1,600 in 22, and 1:3,200 or higher in 33. From the 71 farms visited, 69 had seropositive humans. Prevalence of anti-T. gondii antibodies increased with age of the people (P < 0.05), and no difference was observed in the occurrence by gender (P > 0.05). A sanitary questionnaire was applied in each farm, and statistical association between the serologic status and several variables were analyzed. Home-grown vegetable consumption and origin of drinking water (well or river) were the independent variables that displayed significant association (P = 0.002 and 0.02, respectively). Higher values of occurrence were found in people with consumption of home-grown vegetables (76.1%) and people that drink well water (75.4%) compared with people that did not consume this type of food (61.9%) and drink river water (55.2%). By IFAT (> or = 1:16), 194 of 266 (73%) humans were seropositive and there was a good correlation between MAT and IFAT.

Molecular Epidemiology of Epidemic Severe Malaria Caused by Plasmodium vivax in the State of Amazonas, Brazil

DTIC Science & Technology

2005-01-01

Quinnan Jr. M.D., PMB Malaria in South America is a major public health problem. In Brazil, most of the cases occur in the Amazon Region...chain reaction products from DNA extracted from blood smears collected from patients with malaria in the Amazon Region in the 1970s 62 Figure 17...267 1 Hypothesis and Specific Aims In Brazil, malaria is largely restricted to the Amazon Region, and is particularly prevalent in

Swath-altimetry measurements of the main stem Amazon River: measurement errors and hydraulic implications

NASA Astrophysics Data System (ADS)

Wilson, M. D.; Durand, M.; Jung, H. C.; Alsdorf, D.

2015-04-01

The Surface Water and Ocean Topography (SWOT) mission, scheduled for launch in 2020, will provide a step-change improvement in the measurement of terrestrial surface-water storage and dynamics. In particular, it will provide the first, routine two-dimensional measurements of water-surface elevations. In this paper, we aimed to (i) characterise and illustrate in two dimensions the errors which may be found in SWOT swath measurements of terrestrial surface water, (ii) simulate the spatio-temporal sampling scheme of SWOT for the Amazon, and (iii) assess the impact of each of these on estimates of water-surface slope and river discharge which may be obtained from SWOT imagery. We based our analysis on a virtual mission for a ~260 km reach of the central Amazon (Solimões) River, using a hydraulic model to provide water-surface elevations according to SWOT spatio-temporal sampling to which errors were added based on a two-dimensional height error spectrum derived from the SWOT design requirements. We thereby obtained water-surface elevation measurements for the Amazon main stem as may be observed by SWOT. Using these measurements, we derived estimates of river slope and discharge and compared them to those obtained directly from the hydraulic model. We found that cross-channel and along-reach averaging of SWOT measurements using reach lengths greater than 4 km for the Solimões and 7.5 km for Purus reduced the effect of systematic height errors, enabling discharge to be reproduced accurately from the water height, assuming known bathymetry and friction. Using cross-sectional averaging and 20 km reach lengths, results show Nash-Sutcliffe model efficiency values of 0.99 for the Solimões and 0.88 for the Purus, with 2.6 and 19.1 % average overall error in discharge, respectively. We extend the results to other rivers worldwide and infer that SWOT-derived discharge estimates may be more accurate for rivers with larger channel widths (permitting a greater level of cross-sectional averaging and the use of shorter reach lengths) and higher water-surface slopes (reducing the proportional impact of slope errors on discharge calculation).

Histidine-rich protein 2 (pfhrp2) and pfhrp3 gene deletions in Plasmodium falciparum isolates from select sites in Brazil and Bolivia.

PubMed

Rachid Viana, Giselle Maria; Akinyi Okoth, Sheila; Silva-Flannery, Luciana; Lima Barbosa, Danielle Regina; Macedo de Oliveira, Alexandre; Goldman, Ira F; Morton, Lindsay C; Huber, Curtis; Anez, Arletta; Dantas Machado, Ricardo Luiz; Aranha Camargo, Luís Marcelo; Costa Negreiros do Valle, Suiane; Marins Póvoa, Marinete; Udhayakumar, Venkatachalam; Barnwell, John W

2017-01-01

More than 80% of available malaria rapid diagnostic tests (RDTs) are based on the detection of histidine-rich protein-2 (PfHRP2) for diagnosis of Plasmodium falciparum malaria. Recent studies have shown the genes that code for this protein and its paralog, histidine-rich protein-3 (PfHRP3), are absent in parasites from the Peruvian Amazon Basin. Lack of PfHRP2 protein through deletion of the pfhrp2 gene leads to false-negative RDT results for P. falciparum. We have evaluated the extent of pfhrp2 and pfhrp3 gene deletions in a convenience sample of 198 isolates from six sites in three states across the Brazilian Amazon Basin (Acre, Rondonia and Para) and 25 isolates from two sites in Bolivia collected at different times between 2010 and 2012. Pfhrp2 and pfhrp3 gene and their flanking genes on chromosomes 7 and 13, respectively, were amplified from 198 blood specimens collected in Brazil. In Brazil, the isolates collected in Acre state, located in the western part of the Brazilian Amazon, had the highest percentage of deletions for pfhrp2 25 (31.2%) of 79, while among those collected in Rondonia, the prevalence of pfhrp2 gene deletion was only 3.3% (2 out of 60 patients). In isolates from Para state, all parasites were pfhrp2-positive. In contrast, we detected high proportions of isolates from all 3 states that were pfhrp3-negative ranging from 18.3% (11 out of 60 samples) to 50.9% (30 out of 59 samples). In Bolivia, only one of 25 samples (4%) tested had deleted pfhrp2 gene, while 68% (17 out of 25 samples) were pfhrp3-negative. Among the isolates tested, P. falciparum pfhrp2 gene deletions were present mainly in those from Acre State in the Brazilian Amazon. These results indicate it is important to reconsider the use of PfHRP2-based RDTs in the western region of the Brazilian Amazon and to implement appropriate surveillance systems to monitor pfhrp2 gene deletions in this and other parts of the Amazon region.

Histidine-rich protein 2 (pfhrp2) and pfhrp3 gene deletions in Plasmodium falciparum isolates from select sites in Brazil and Bolivia

PubMed Central

Rachid Viana, Giselle Maria; Akinyi Okoth, Sheila; Silva-Flannery, Luciana; Lima Barbosa, Danielle Regina; Macedo de Oliveira, Alexandre; Goldman, Ira F.; Morton, Lindsay C.; Huber, Curtis; Anez, Arletta; Dantas Machado, Ricardo Luiz; Aranha Camargo, Luís Marcelo; Costa Negreiros do Valle, Suiane; Marins Póvoa, Marinete; Barnwell, John W.

2017-01-01

More than 80% of available malaria rapid diagnostic tests (RDTs) are based on the detection of histidine-rich protein-2 (PfHRP2) for diagnosis of Plasmodium falciparum malaria. Recent studies have shown the genes that code for this protein and its paralog, histidine-rich protein-3 (PfHRP3), are absent in parasites from the Peruvian Amazon Basin. Lack of PfHRP2 protein through deletion of the pfhrp2 gene leads to false-negative RDT results for P. falciparum. We have evaluated the extent of pfhrp2 and pfhrp3 gene deletions in a convenience sample of 198 isolates from six sites in three states across the Brazilian Amazon Basin (Acre, Rondonia and Para) and 25 isolates from two sites in Bolivia collected at different times between 2010 and 2012. Pfhrp2 and pfhrp3 gene and their flanking genes on chromosomes 7 and 13, respectively, were amplified from 198 blood specimens collected in Brazil. In Brazil, the isolates collected in Acre state, located in the western part of the Brazilian Amazon, had the highest percentage of deletions for pfhrp2 25 (31.2%) of 79, while among those collected in Rondonia, the prevalence of pfhrp2 gene deletion was only 3.3% (2 out of 60 patients). In isolates from Para state, all parasites were pfhrp2-positive. In contrast, we detected high proportions of isolates from all 3 states that were pfhrp3-negative ranging from 18.3% (11 out of 60 samples) to 50.9% (30 out of 59 samples). In Bolivia, only one of 25 samples (4%) tested had deleted pfhrp2 gene, while 68% (17 out of 25 samples) were pfhrp3-negative. Among the isolates tested, P. falciparum pfhrp2 gene deletions were present mainly in those from Acre State in the Brazilian Amazon. These results indicate it is important to reconsider the use of PfHRP2-based RDTs in the western region of the Brazilian Amazon and to implement appropriate surveillance systems to monitor pfhrp2 gene deletions in this and other parts of the Amazon region. PMID:28301474

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dubey, Manvendra Krishna

Forests soak up 25% of the carbon dioxide (CO 2) emitted by anthropogenic fossil energy use (10 Gt C y -1) moderating its atmospheric accumulation. How this terrestrial CO 2 uptake will evolve with climate change in the 21st century is largely unknown. Rainforests are the most active ecosystems with the Amazon basin storing 120 Gt C as biomass and exchanging 18 Gt C y -1 of CO 2 via photosynthesis and respiration and fixing carbon at 2-3 kg C m -2 y -1. Furthermore, the intense hydrologic and carbon cycles are tightly coupled in the Amazon where about halfmore » of the water is recycled by evapotranspiration and the other half imported from the ocean by Northeasterly trade winds. Climate models predict a drying in the Amazon with reduced carbon uptake while observationally guided assessments indicate sustained uptake. We will resolve this huge discrepancy in the size and sign of the future Amazon carbon cycle by performing the first simultaneous regional scale high frequency measurements of atmospheric CO 2, H 2O, HOD, CH 4, N 2O and CO at the T3 site in Manacupuru, Brazil as part of DOE's GoAmazon project. Our data will be used to inform and develop DOE's CLM on the tropical carbon-water couplings at the appropriate grid scale (10-50km). Our measurements will also validate the CO 2 data from Japan's GOSAT and NASA's imminent OCO-2 satellite (launch date July 2014).« less

Improving the Amazonian Hydrologic Cycle in a Coupled Land-Atmosphere, Single Column Model

NASA Astrophysics Data System (ADS)

Harper, A. B.; Denning, S.; Baker, I.; Prihodko, L.; Branson, M.

2006-12-01

We have coupled a land-surface model, the Simple Biosphere Model (SiB3), to a single column of the Colorado State University General Circulation Model (CSU-GCM) in the Amazon River Basin. This is a preliminary step in the broader goal of improved simulation of Basin-wide hydrology. A previous version of the coupled model (SiB2) showed drought and catastrophic dieback of the Amazon rain forest. SiB3 includes updated soil hydrology and root physiology. Our test area for the coupled single column model is near Santarem, Brazil, where measurements from the km 83 flux tower in the Tapajos National Forest can be used to evaluate model output. The model was run for 2001 using NCEP2 Reanalysis as driver data. Preliminary results show that the updated biosphere model coupled to the GCM produces improved simulations of the seasonal cycle of surface water balance and precipitation. Comparisons of the diurnal and seasonal cycles of surface fluxes are also being made.

Inundation and Gas Fluxes from Amazon Lakes and Wetlands

NASA Astrophysics Data System (ADS)

Melack, J. M.; MacIntyre, S.; Forsberg, B. R.; Amaral, J. H.; Barbosa, P.

2015-12-01

Inundation areas and wetland habitats for the lowland Amazon basin derived remote sensing with synthetic aperture radar are combined with measurements of greenhouse gas evasion derived from field measurements and new formulations of atmosphere-water. On-going field studies in representative aquatic habitats on the central Amazon floodplain are combining monthly measurements of carbon dioxide and methane concentrations and fluxes to the atmosphere with deployment of meteorological sensors and high-resolution thermistors and optical dissolved oxygen sensors. A real-time cavity ringdown spectrometer is being used to determine the gas concentrations; vertical profiles were obtained by using an equilibrator to extract gases from water, and floating chambers are used to assess fluxes. Gas fluxes varied as a function of season, habitat and water depth. Greatest carbon dioxide fluxes occurred during high and falling water levels. During low water, periods with high chlorophyll, indicative of phytoplankton, the flux of carbon dioxide switched from being emitted from the lake to being taken-up by the lake some of the time. The highest pCO2 concentration (5500 μatm) was about three times higher than the median (1700 μatm). Higher CO2 fluxes were observed in open water than in areas with flooded or floating vegetation. In contrast, methane fluxes were higher in vegetated regions. We measured turbulence as rate of dissipation of turbulent kinetic energy based on microstructure profiling. Comparison of these measurements with those calculated from meteorological and time series measurements validated new equations for turbulent kinetic energy dissipation (TKE) rates during moderate winds and cooling and illustrated that the highest dissipation rates occurred under heating. Measured gas exchange coefficients (k600) were similar to those based on the TKE dissipation rates and are well described using the surface renewal model. These k values are several times higher than previous values applied to regional extrapolations in the Amazon basin and elsewhere.

Aerial and surface rivers: downwind impacts on water availability from land use changes in Amazonia

NASA Astrophysics Data System (ADS)

Weng, Wei; Luedeke, Matthias K. B.; Zemp, Delphine C.; Lakes, Tobia; Kropp, Juergen P.

2018-02-01

The abundant evapotranspiration provided by the Amazon forests is an important component of the hydrological cycle, both regionally and globally. Since the last century, deforestation and expanding agricultural activities have been changing the ecosystem and its provision of moisture to the atmosphere. However, it remains uncertain how the ongoing land use change will influence rainfall, runoff, and water availability as findings from previous studies differ. Using moisture tracking experiments based on observational data, we provide a spatially detailed analysis recognizing potential teleconnection between source and sink regions of atmospheric moisture. We apply land use scenarios in upwind moisture sources and quantify the corresponding rainfall and runoff changes in downwind moisture sinks. We find spatially varying responses of water regimes to land use changes, which may explain the diverse results from previous studies. Parts of the Peruvian Amazon and western Bolivia are identified as the sink areas most sensitive to land use change in the Amazon and we highlight the current water stress by Amazonian land use change on these areas in terms of the water availability. Furthermore, we also identify the influential source areas where land use change may considerably reduce a given target sink's water reception (from our example of the Ucayali River basin outlet, rainfall by 5-12 % and runoff by 19-50 % according to scenarios). Sensitive sinks and influential sources are therefore suggested as hotspots for achieving sustainable land-water management.

Oyster Fisheries App

NASA Technical Reports Server (NTRS)

Perez Guerrero, Geraldo A.; Armstrong, Duane; Underwood, Lauren

2015-01-01

This project is creating a cloud-enabled, HTML 5 web application to help oyster fishermen and state agencies apply Earth science to improve the management of this important natural and economic resource. The Oyster Fisheries app gathers and analyzes environmental and water quality information, and alerts fishermen and resources managers about problems in oyster fishing waters. An intuitive interface based on Google Maps displays the geospatial information and provides familiar interactive controls to the users. Alerts can be tailored to notify users when conditions in specific leases or public fishing areas require attention. The app is hosted on the Amazon Web Services cloud. It is being developed and tested using some of the latest web development tools such as web components and Polymer.

The economic value of the climate regulation ecosystem service provided by the Amazon rainforest

NASA Astrophysics Data System (ADS)

Heil Costa, Marcos; Pires, Gabrielle; Fontes, Vitor; Brumatti, Livia

2017-04-01

The rainy Amazon climate allowed important activities to develop in the region as large rainfed agricultural lands and hydropower plants. The Amazon rainforest is an important source of moisture to the regional atmosphere and helps regulate the local climate. The replacement of forest by agricultural lands decreases the flux of water vapor into the atmosphere and changes the precipitation patterns, which may severely affect such economic activities. Assign an economic value to this ecosystem service may emphasize the significance to preserve the Amazon rainforest. In this work, we provide a first approximation of the quantification of the climate regulation ecosystem service provided by the Amazon rainforest using the marginal production method. We use climate scenarios derived from Amazon deforestation scenarios as input to crop and runoff models to assess how land use change would affect agriculture and hydropower generation. The effects of forest removal on soybean production and on cattle beef production can both be as high as US 16 per year per ha deforested, and the effects on hydropower generation can be as high as US 8 per year per ha deforested. We consider this as a conservative estimate of a permanent service provided by the rainforest. Policy makers and other Amazon agriculture and energy businesses must be aware of these numbers, and consider them while planning their activities.

Using remote sensing for validation of a large scale hydrologic and hydrodynamic model in the Amazon

NASA Astrophysics Data System (ADS)

Paiva, R. C.; Bonnet, M.; Buarque, D. C.; Collischonn, W.; Frappart, F.; Mendes, C. B.

2011-12-01

We present the validation of the large-scale, catchment-based hydrological MGB-IPH model in the Amazon River basin. In this model, physically-based equations are used to simulate the hydrological processes, such as the Penman Monteith method to estimate evapotranspiration, or the Moore and Clarke infiltration model. A new feature recently introduced in the model is a 1D hydrodynamic module for river routing. It uses the full Saint-Venant equations and a simple floodplain storage model. River and floodplain geometry parameters are extracted from SRTM DEM using specially developed GIS algorithms that provide catchment discretization, estimation of river cross-sections geometry and water storage volume variations in the floodplains. The model was forced using satellite-derived daily rainfall TRMM 3B42, calibrated against discharge data and first validated using daily discharges and water levels from 111 and 69 stream gauges, respectively. Then, we performed a validation against remote sensing derived hydrological products, including (i) monthly Terrestrial Water Storage (TWS) anomalies derived from GRACE, (ii) river water levels derived from ENVISAT satellite altimetry data (212 virtual stations from Santos da Silva et al., 2010) and (iii) a multi-satellite monthly global inundation extent dataset at ~25 x 25 km spatial resolution (Papa et al., 2010). Validation against river discharges shows good performance of the MGB-IPH model. For 70% of the stream gauges, the Nash and Suttcliffe efficiency index (ENS) is higher than 0.6 and at Óbidos, close to Amazon river outlet, ENS equals 0.9 and the model bias equals,-4.6%. Largest errors are located in drainage areas outside Brazil and we speculate that it is due to the poor quality of rainfall datasets in these areas poorly monitored and/or mountainous. Validation against water levels shows that model is performing well in the major tributaries. For 60% of virtual stations, ENS is higher than 0.6. But, similarly, largest errors are also located in drainage areas outside Brazil, mostly Japurá River, and in the lower Amazon River. In the latter, correlation with observations is high but the model underestimates the amplitude of water levels. We also found a large bias between model and ENVISAT water levels, ranging from -3 to -15 m. The model provided TWS in good accordance with GRACE estimates. ENS values for TWS over the whole Amazon equals 0.93. We also analyzed results in 21 sub-regions of 4 x 4°. ENS is smaller than 0.8 only in 5 areas, and these are found mostly in the northwest part of the Amazon, possibly due to same errors reported in discharge results. Flood extent validation is under development, but a previous analysis in Brazilian part of Solimões River basin suggests a good model performance. The authors are grateful for the financial and operational support from the brazilian agencies FINEP, CNPq and ANA and from the french observatories HYBAM and SOERE RBV.

On the sensitivity of the diurnal cycle in the Amazon to convective intensity

PubMed Central

Taylor, Patrick C.; Dodson, Jason B.; Tawfik, Ahmed B.

2016-01-01

Abstract Climate and reanalysis models contain large water and energy budget errors over tropical land related to the misrepresentation of diurnally forced moist convection. Motivated by recent work suggesting that the water and energy budget is influenced by the sensitivity of the convective diurnal cycle to atmospheric state, this study investigates the relationship between convective intensity, the convective diurnal cycle, and atmospheric state in a region of frequent convection—the Amazon. Daily, 3‐hourly satellite observations of top of atmosphere (TOA) fluxes from Clouds and the Earth's Radiant Energy System Ed3a SYN1DEG and precipitation from Tropical Rainfall Measuring Mission 3B42 data sets are collocated with twice daily Integrated Global Radiosonde Archive observations from 2002 to 2012 and hourly flux tower observations. Percentiles of daily minimum outgoing longwave radiation are used to define convective intensity regimes. The results indicate a significant increase in the convective diurnal cycle amplitude with increased convective intensity. The TOA flux diurnal phase exhibits 1–3 h shifts with convective intensity, and precipitation phase is less sensitive. However, the timing of precipitation onset occurs 2–3 h earlier and the duration lasts 3–5 h longer on very convective compared to stable days. While statistically significant changes are found between morning atmospheric state and convective intensity, variations in upper and lower tropospheric humidity exhibit the strongest relationships with convective intensity and diurnal cycle characteristics. Lastly, convective available potential energy (CAPE) is found to vary with convective intensity but does not explain the variations in Amazonian convection, suggesting that a CAPE‐based convective parameterization will not capture the observed behavior without incorporating the sensitivity of convection to column humidity. PMID:27867784

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

DOE PAGES

Restrepo-Coupe, Natalia; Levine, Naomi M.; Christoffersen, Bradley O.; ...

2016-08-29

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Restrepo-Coupe, Natalia; Levine, Naomi M.; Christoffersen, Bradley O.

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

Regional controls on geomorphology, hydrology, and ecosystem integrity in the Orinoco Delta, Venezuela

USGS Publications Warehouse

Warne, A.G.; Meade, R.H.; White, W.A.; Guevara, E.H.; Gibeaut, J.; Smyth, R.C.; Aslan, A.; Tremblay, T.

2002-01-01

Interacting river discharge, tidal oscillation, and tropical rainfall across the 22,000 km2 Orinoco delta plain support diverse fresh and brackish water ecosystems. To develop environmental baseline information for this largely unpopulated region, we evaluate major coastal plain, shallow marine, and river systems of northeastern South America, which serves to identify principal sources and controls of water and sediment flow into, through, and out of the Orinoco Delta. The regional analysis includes a summary of the geology, hydrodynamics, sediment dynamics, and geomorphic characteristics of the Orinoco drainage basin, river, and delta system. Because the Amazon River is a major source of sediment deposited along the Orinoco coast, we summarize Amazon water and sediment input to the northeastern South American littoral zone. We investigate sediment dynamics and geomorphology of the Guiana coast, where marine processes and Holocene history are similar to the Orinoco coast. Major factors controlling Orinoco Delta water and sediment dynamics include the pronounced annual flood discharge; the uneven distribution of water and sediment discharge across the delta plain; discharge of large volumes of water with low sediment concentrations through the Rio Grande and Araguao distributaries; water and sediment dynamics associated with the Guayana littoral current along the northeastern South American coast; inflow of large volumes of Amazon sediment to the Orinoco coast; development of a fresh water plume seaward of Boca Grande; disruption of the Guayana Current by Trinidad, Boca de Serpientes, and Gulf of Paria; and the constriction at Boca de Serpientes. ?? 2002 Elsevier Science B.V. All rights reserved.

Eo-1 Hyperion Measures Canopy Drought Stress In Amazonia

NASA Technical Reports Server (NTRS)

Asner, Gregory P.; Nepstad, Daniel; Cardinot, Gina; Moutinho, Paulo; Harris, Thomas; Ray, David

2004-01-01

The central, south and southeast portions of the Amazon Basin experience a period of decreased cloud cover and precipitation from June through November. There are likely important effects of seasonal and interannual rainfall variation on forest leaf area index, canopy water stress, productivity and regional carbon cycling in the Amazon. While both ground and spaceborne studies of precipitation continue to improve, there has been almost no progress made in observing forest canopy responses to rainfall variability in the humid tropics. This shortfall stems from the large stature of the vegetation and great spatial extent of tropical forests, both of which strongly impede field studies of forest responses to water availability. Those few studies employing satellite measures of canopy responses to seasonal and interannual drought (e.g., Bohlman et al. 1998, Asner et al. 2000) have been limited by the spectral resolution and sampling available from Landsat and AVHRR sensors. We report on a study combining the first landscape-level, managed drought experiment in Amazon tropical forest with the first spaceborne imaging spectrometer observations of this experimental area. Using extensive field data on rainfall inputs, soil water content, and both leaf and canopy responses, we test the hypothesis that spectroscopic signatures unique to hyperspectral observations can be used to quantify relative differences in canopy stress resulting from water availability.

Origin of Amazon mudbanks along the northeastern coast of South America

USGS Publications Warehouse

Allison, M.A.; Lee, M.T.; Ogston, A.S.; Aller, R.C.

2000-01-01

Seismic profiles, sediment cores, and water column measurements were collected along the northeastern coast of Brazil to examine the origin of mudbanks in the Amazon coastal mud belt. These 10-60-km-long, shore-attached features previously had been observed to migrate along the 1200 km coast of the Guianas in response to wave forcing. CHIRP (3.5 kHz) seismic profiles of the shoreface and inner shelf located two mudbanks updrift of the previous eastern limit in French Guiana. 210Pb geochronology shows that these two banks are migrating to the northwest over a relict mud surface in 5-20 m water depth. The mudbanks are 3-4 m thick and are translating over a modern shoreface mud wedge deposited by previous mudbank passage in < 5 m water depth. Initial mudbank development is taking place on the intertidal and shallow subtidal mudflats at Cabo Cassipore, associated with an alongshore-accreting clinoform feature. Sediment trapping in this area is controlled by the nearshore presence of strong water column stratification produced by the enormous Amazon freshwater discharge on the shelf and by proximity to the Cassipore River estuary. Seasonal and decadal periods of sediment supply and starvation in this area likely are controlled by variations in northwest trade wind intensity. (C) 2000 Elsevier Science B.V.

Energy at the Junction of the Rivers Negro and Solimões, Contributors of the Amazon River, in the Brazilian Amazon

PubMed Central

de Souza, Paulo Kroeff

2014-01-01

The Negro and Solimoes rivers join in front of the Brazilian city of Manaus to form the Amazon River. This “meeting of the waters” is a natural phenomenon of great aesthetic beauty that has been the focus of attention of researchers all over the world in various scientific fields. The waters of the Negro are darker and warmer, while the waters of the Solimoes are lighter and cooler. These waters have very different characteristics and remain without mixing, flowing side by side for several miles. Some reports indicate a temperature gradient between the waters of the order of 6°C, which can be used in conjunction with very high flow rates delivered by the two rivers, with a heat engine operating on a thermodynamic cycle to provide electricity. This review paper identifies this energy resource and presents a preliminary assessment of the potential for power generation. A realistic assessment of the potential points to an available power of about 1 GW. It is clear that further studies are needed to accurately assess the available thermal gradient and its variation over time, to move forward in the design of the power converter, and to establish an appropriate location for a power plant. PMID:27437451

Amazon Forests Maintain Consistent Canopy Structure and Greenness During the Dry Season

NASA Technical Reports Server (NTRS)

Morton, Douglas C.; Nagol, Jyoteshwar; Carabajal, Claudia C.; Rosette, Jacqueline; Palace, Michael; Cook, Bruce D.; Vermote, Eric F.; Harding, David J.; North, Peter R. J.

2014-01-01

The seasonality of sunlight and rainfall regulates net primary production in tropical forests. Previous studies have suggested that light is more limiting than water for tropical forest productivity, consistent with greening of Amazon forests during the dry season in satellite data.We evaluated four potential mechanisms for the seasonal green-up phenomenon, including increases in leaf area or leaf reflectance, using a sophisticated radiative transfer model and independent satellite observations from lidar and optical sensors. Here we show that the apparent green up of Amazon forests in optical remote sensing data resulted from seasonal changes in near-infrared reflectance, an artefact of variations in sun-sensor geometry. Correcting this bidirectional reflectance effect eliminated seasonal changes in surface reflectance, consistent with independent lidar observations and model simulations with unchanging canopy properties. The stability of Amazon forest structure and reflectance over seasonal timescales challenges the paradigm of light-limited net primary production in Amazon forests and enhanced forest growth during drought conditions. Correcting optical remote sensing data for artefacts of sun-sensor geometry is essential to isolate the response of global vegetation to seasonal and interannual climate variability.

Amazon forests maintain consistent canopy structure and greenness during the dry season.

PubMed

Morton, Douglas C; Nagol, Jyoteshwar; Carabajal, Claudia C; Rosette, Jacqueline; Palace, Michael; Cook, Bruce D; Vermote, Eric F; Harding, David J; North, Peter R J

2014-02-13

The seasonality of sunlight and rainfall regulates net primary production in tropical forests. Previous studies have suggested that light is more limiting than water for tropical forest productivity, consistent with greening of Amazon forests during the dry season in satellite data. We evaluated four potential mechanisms for the seasonal green-up phenomenon, including increases in leaf area or leaf reflectance, using a sophisticated radiative transfer model and independent satellite observations from lidar and optical sensors. Here we show that the apparent green up of Amazon forests in optical remote sensing data resulted from seasonal changes in near-infrared reflectance, an artefact of variations in sun-sensor geometry. Correcting this bidirectional reflectance effect eliminated seasonal changes in surface reflectance, consistent with independent lidar observations and model simulations with unchanging canopy properties. The stability of Amazon forest structure and reflectance over seasonal timescales challenges the paradigm of light-limited net primary production in Amazon forests and enhanced forest growth during drought conditions. Correcting optical remote sensing data for artefacts of sun-sensor geometry is essential to isolate the response of global vegetation to seasonal and interannual climate variability.

Links between land use change and recent dry season droughts in Amazonia

NASA Astrophysics Data System (ADS)

Khanna, J.; Medvigy, D.

2012-12-01

The Amazon region experienced catastrophic and unusually severe droughts in 2005 and 2010. These two droughts were phenomenologically different from the other, more common, El Niño-related droughts. Whereas El Niño-related droughts mostly affect the eastern and south-eastern parts of the region during the wet season (December-March), the droughts of 2005 and 2010 were most severe during the dry season (June-August) and affected the southern and western parts of the Amazon. A global warming driven mechanism has been suggested for these droughts wherein decreased moisture transport into the basin during the dry season is caused by anomalously high tropical north Atlantic SSTs, which weaken the northern hemisphere Hadley cell. But the facts that dry season droughts have been historically rare in this region and that the 2005 and 2010 droughts were strongest around locations of recent land use change activity suggest that deforestation may be contributing to this inter-annual variability in precipitation. This study addresses this research question by numerically modeling the 2005 and 2010 drought events for two land use scenarios, one of which (Deforested or DEF) represents the current state of land use in the Amazon and the other (Pristine Forest or PRF) represents a scenario of no deforestation. A variable resolution GCM, the Ocean-Land-Atmosphere Model (OLAM), is used to model these events. Land surface processes and soil moisture during the drought period are simulated using the Land Ecosystem Atmosphere Feedback model. The state of land cover in the Amazon in the two drought years is obtained from satellite-based land cover maps. The land grid has a variable resolution ranging from ≈75km in the South American sector to ≈200km elsewhere. This variable-resolution approach helps resolve topographic features and the medium-to-large scale land use patches in the Amazon area. The atmospheric runs are forced by National Oceanic and Atmospheric Administration weekly sea-surface temperature data. Soil moisture initial conditions were obtained from 8-year spin-ups for DEF and PRF. Then, ensembles of 18 month simulations were carried out, starting in June of 2004 and 2009. The ensembles consisted of 5 runs for each of the DEF and PRF experiments and are designed to reduce the effects of natural climate variability on the model results. Results are analyzed to test whether the intensity of the droughts, as measured by a water deficit index like maximum climatological water deficit (MCWD), increases from the PRF to the DEF case. An analysis of the statistical differences between the values of various meteorological and hydrological variables as obtained from the two land use scenarios will be presented. Thus this study will help both qualify and quantify the extent to which land use change can intensify a drought event.

Simulating floods in the Amazon River Basin: Impacts of new river geomorphic and dynamic flow parameterizations

NASA Astrophysics Data System (ADS)

Coe, M. T.; Costa, M. H.; Howard, E. A.

2006-12-01

In this paper we analyze the hydrology of the Amazon River system for the latter half of the 20th century with our recently completed model of terrestrial hydrology (Terrestrial Hydrology Model with Biogeochemistry, THMB). We evaluate the simulated hydrology of the Central Amazon basin against limited observations of river discharge, floodplain inundation, and water height and analyze the spatial and temporal variability of the hydrology for the period 1939-1998. We compare the simulated discharge and floodplain inundated area to the simulations by Coe et al., 2002 using a previous version of this model. The new model simulates the discharge and flooded area in better agreement with the observations than the previous model. The coefficient of correlation between the simulated and observed discharge for the greater than 27000 monthly observations of discharge at 120 sites throughout the Brazilian Amazon is 0.9874 compared to 0.9744 for the previous model. The coefficient of correlation between the simulated monthly flooded area and the satellite-based estimates by Sippel et al., 1998 exceeds 0.7 for 8 of the 12 mainstem reaches. The seasonal and inter-annual variability of the water height and the river slope compares favorably to the satellite altimetric measurements of height reported by Birkett et al., 2002.

Larval habitats of Anopheles species in a rural settlement on the malaria frontier of southwest Amazon, Brazil.

PubMed

Rufalco-Moutinho, Paulo; Schweigmann, Nicolás; Bergamaschi, Denise Pimentel; Mureb Sallum, Maria Anice

2016-12-01

Rural settlements are social arrangements expanding in the Amazon region, which generate disturbances in the natural environment, thus affecting the ecology of the species of Anopheles and thus the malaria transmission. Larval habitats are important sources for maintenance of mosquito vector populations, and holding back a natural watercourse is a usual process in the establishment of rural settlements, since the formation of micro-dams represents a water resource for the new settlers. Identifying characteristics of the larval habitats that may be associated with both the presence and abundance of Anopheles vectors species in an environment under ecological transition is background for planning vector control strategies in rural areas in the Amazon. Anopheles larvae collections were performed in two major types of habitats: natural and flow-limited water collections that were constructed by holding back the original watercourse. A total of 3123 Anopheles spp. larvae were captured in three field-sampling collections. The majority of the larvae identified were taken from flow-limited water collections belonged to species of the Nyssorhynchus subgenus (92%), whereas in the natural larval habitats a fewer number of individuals belonged to the Stethomyia (5%) and Anopheles (3%) subgenera. The total of Nyssorhynchus identified (1818), 501 specimens belonged to An. darlingi, 750 to An. triannulatus and 567 for others remaining species. In addition, 1152 could not be identified to subgenus/species level, because they were either in the first-instar or damaged. The primary vector in areas of the Amazon river basin, An. darlingi, was found exclusively in man-made habitats. Statistical analysis display An. triannulatus with specialist behavior for characteristics of man-made habitats. Modifications in the natural environment facilitate the rise of larval habitats for species with epidemiological importance for malaria in the region. This study showed that man-made habitats flow-limited water collections from dry lands could be a factor associated with the increase of An. darlingi and An. triannulatus populations, and other Nyssorhynchus species as well in endemic areas of the Amazon Region. Copyright © 2016 Elsevier B.V. All rights reserved.

Guarana: revisiting a highly caffeinated plant from the Amazon.

PubMed

Schimpl, Flávia Camila; da Silva, José Ferreira; Gonçalves, José Francisco de Carvalho; Mazzafera, Paulo

2013-10-28

Guarana (Paullinia cupana Kunth var. sorbilis (Mart.) Ducke) has been traditionally consumed by indigenous communities of the Amazon region. It is valued mainly for its stimulant property because of its high content of caffeine, which can be up to 6% in the seeds. The purpose of this review is to revisit this typically Brazilian plant, addressing economic considerations, the chemical makeup of the seeds and pharmacological properties so far investigated. Guarana is primarily produced in the Brazilian states of Amazonas and Bahia, and approximately 70% of the production is used by the industry of soft and energy drinks. The other 30% becomes guarana powder for direct consumption in capsules or dilution in water, or it serves as a raw material for the pharmaceutical and cosmetics industries. In addition to its stimulant property, guarana has other therapeutic properties, which have aroused the interest of the scientific community. This review shows that other guarana properties may be explored and how scarce are the studies regarding agronomic, plant pathology, physiology and breeding. So far, caffeine has been the main reason to study guarana and still will lead the researches because the demand for this alkaloid by food and pharmaceutical industry, and a strongly growing market related with beauty products. However, guarana has other components and there is great interest in studies designed to elucidate the effects of guarana's bioactive components and their potential pharmacological applications. Significant part of the guarana production in Brazil still comes from Indians tribes in the Amazon State, and any improvement in this plant, in any aspect, may propitiate a positive economic impact in their lives. © 2013 Elsevier Ireland Ltd. All rights reserved.

Molecular assays reveal the presence of Theileria spp. and Babesia spp. in Asian water buffaloes (Bubalus bubalis, Linnaeus, 1758) in the Amazon region of Brazil.

PubMed

Silveira, Júlia A G; de Oliveira, Cairo H S; Silvestre, Bruna T; Albernaz, Tatiana T; Leite, Rômulo C; Barbosa, José D; Oliveira, Carlos M C; Ribeiro, Múcio F B

2016-07-01

Approximately 50% of buffalo herds in Brazil are located in Pará state in northern Brazil. There are several properties where cattle and buffalo live and graze together, and thus, buffalo pathogens may threaten the health of cattle and vice versa. Therefore, knowledge of infectious agents of buffalo is essential for maintaining healthy livestock. Clinical disease caused by Theileria and Babesia parasites in the Asian water buffalo is not common, although these animals may act as reservoir hosts, and the detection of these hemoparasites in buffaloes is as important as it is in cattle. Studies of the infection of buffaloes by hemoparasites in Brazil are scarce. The objective of the present study was to investigate the occurrence of Piroplasmida parasites in Asian water buffaloes in the state of Pará in the Amazon region of Brazil using nested PCR assays and phylogenetic analysis. The 18S rRNA gene and ITS complete region were amplified from DNA extracted from blood samples collected from 308 apparently healthy buffaloes bred on six properties in the state of Pará, Brazil. The prevalence of positive buffalo samples was 4.2% (13/308) for Theileria spp., 3.6% (11/308) for Babesia bovis and 1% (3/308) for Babesia bigemina. Animals infected with Theileria were detected in 50% (3/6) of the assessed properties. Phylogenetic analyses indicated that the Theileria species detected in this study were closely related to Theileria buffeli, Theileria orientalis and Theileria sinensis. To our knowledge, this is the first report of Theileria in Asian water buffaloes in the Americas. The majority of Theileria-positive buffaloes (11/13) belong to a property that has a history of animals presenting lymphoproliferative disease of unknown etiology. Therefore, the present research suggests that this disorder can be associated with Theileria infection in this property. Our results provide new insights on the distribution and biological aspects of hemoparasites transmissible from buffaloes to cattle. Copyright © 2016 Elsevier GmbH. All rights reserved.

76 FR 23642 - Culturally Significant Objects Imported for Exhibition Determinations: “Marajo: Ancient Ceramics...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-27

... DEPARTMENT OF STATE [Public Notice: 7432] Culturally Significant Objects Imported for Exhibition Determinations: ``Marajo: Ancient Ceramics at the Mouth of the Amazon'' SUMMARY: Notice is hereby given of the... that the objects to be included in the exhibition ``Marajo: Ancient Ceramics at the Mouth of the Amazon...

Beyond harm’s reach? Submersion of river turtle nesting areas and implications for restoration actions after Amazon hydropower development

PubMed Central

Michalski, Fernanda; Gibbs, James P.

2018-01-01

The global expansion of energy demands combined with abundant rainfall, large water volumes and high flow in tropical rivers have led to an unprecedented expansion of dam constructions in the Amazon. This expansion generates an urgent need for refined approaches to river management; specifically a move away from decision-making governed by overly generalized guidelines. For the first time we quantify direct impacts of hydropower reservoir establishment on an Amazon fresh water turtle. We conducted surveys along 150 km of rivers upstream of a new dam construction during the low water months that correspond to the nesting season of Podocnemis unifilis in the study area. Comparison of nest-areas before (2011, 2015) and after (2016) reservoir filling show that reservoir impacts extend 13% beyond legally defined limits. The submerged nesting areas accounted for a total of 3.8 ha of nesting habitat that was inundated as a direct result of the reservoir filling in 2016. Our findings highlight limitations in the development and implementation of existing Brazilian environmental impact assessment process. We also propose potential ways to mitigate the negative impacts of dams on freshwater turtles and the Amazonian freshwater ecosystems they inhabit. PMID:29333347

Beyond harm's reach? Submersion of river turtle nesting areas and implications for restoration actions after Amazon hydropower development.

PubMed

Norris, Darren; Michalski, Fernanda; Gibbs, James P

2018-01-01

The global expansion of energy demands combined with abundant rainfall, large water volumes and high flow in tropical rivers have led to an unprecedented expansion of dam constructions in the Amazon. This expansion generates an urgent need for refined approaches to river management; specifically a move away from decision-making governed by overly generalized guidelines. For the first time we quantify direct impacts of hydropower reservoir establishment on an Amazon fresh water turtle. We conducted surveys along 150 km of rivers upstream of a new dam construction during the low water months that correspond to the nesting season of Podocnemis unifilis in the study area. Comparison of nest-areas before (2011, 2015) and after (2016) reservoir filling show that reservoir impacts extend 13% beyond legally defined limits. The submerged nesting areas accounted for a total of 3.8 ha of nesting habitat that was inundated as a direct result of the reservoir filling in 2016. Our findings highlight limitations in the development and implementation of existing Brazilian environmental impact assessment process. We also propose potential ways to mitigate the negative impacts of dams on freshwater turtles and the Amazonian freshwater ecosystems they inhabit.

Using CDOM optical properties for estimating DOC concentrations and pCO 2 in the Lower Amazon River

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valerio, Aline de Matos; Kampel, Milton; Vantrepotte, Vincent

Colored dissolved organic matter (CDOM) is largely responsible for the optical properties of freshwaters and coastal areas and can be used as a proxy to assess the non-optical carbon content as the dissolved organic carbon (DOC) and the partial pressure of carbon dioxide (pCO 2). Nevertheless, riverine studies that explores the former relationship are more challenging due to the spectral mixture caused by the high content of inorganic materials in the suspended sediment. Here we evaluate the spatial-temporal variability of CDOM, DOC and pCO 2, as well as the potential of CDOM absorption coefficient (aCDOM(412)) for estimating DOC concentration andmore » pCO 2 along the lower Amazon River. Our results revealed differences in the dissolved organic matter (DOM) quality between clear water (CW) tributaries and the Amazon River mainstem. A linear relationship between DOC and CDOM was observed when tributaries and mainstem are evaluated separately (Amazon waters: N=42, R2=0.74; CW: N= 13, R2 = 0.57). However, this linear relationship was not observed during periods of higher rainfall and river discharge, requiring a model specific to these time periods to be developed (N = 25, R2 = 0.58). A strong linear positive relation was found between aCDOM(412) and pCO 2( N=69, R2=0.65) along the lower river. pCO 2 was less affected by the optical difference between tributaries and mainstem water or by the presence of higher hygrometric conditions when compared to CDOM to DOC relationships. Including the river water temperature in the model improves our ability to estimate pCO 2 (N=69; R2 = 0.80). Our results also illustrate the complexity of DOM temporal dynamics in the lower Amazon River where the occurrence of extreme high and low discharge due to factors such as El Niño, can significantly alter the expected seasonal oscillation, as was the case during this study period. The ability to remotely assess both DOC and pCO 2 from CDOM optical properties highlight the importance of using remote sensing data for monitoring carbon dynamics in large running water systems worldwide.« less

Water availability not fruitfall modulates the dry season distribution of frugivorous terrestrial vertebrates in a lowland Amazon forest

PubMed Central

Paredes, Omar Stalin Landázuri; Norris, Darren; de Oliveira, Tadeu Gomes

2017-01-01

Terrestrial vertebrate frugivores constitute one of the major guilds in tropical forests. Previous studies show that the meso-scale distribution of this group is only weakly explained by variables such as altitude and tree basal area in lowland Amazon forests. For the first time we test whether seasonally limiting resources (water and fallen fruit) affect the dry season distribution in 25 species of terrestrial vertebrates. To examine the effects of the spatial availability of fruit and water on terrestrial vertebrates we used a standardized, regularly spaced arrangement of camera-traps within 25km2 of lowland Amazon forest. Generalized linear models (GLMs) were then used to examine the influence of four variables (altitude, distance to large rivers, distance to nearest water, and presence vs absence of fruits) on the number of photos on five functional groups (all frugivores, small, medium, large and very large frugivores) and on seven of the most abundant frugivore species (Cuniculus paca, Dasyprocta leporina, Mazama americana, Mazama nemorivaga, Myoprocta acouchy, Pecari tajacu and Psophia crepitans). A total of 279 independent photos of 25 species were obtained from 900 camera-trap days. For most species and three functional groups, the variation in the number of photos per camera was significantly but weakly explained by the GLMs (deviance explained ranging from 6.2 to 48.8%). Generally, we found that the presence of water availability was more important than the presence of fallen fruit for the groups and species studied. Medium frugivores, large-bodied frugivores, and two of the more abundant species (C. paca and P. crepitans) were recorded more frequently closer to water bodies; while none of the functional groups nor the most abundant species showed any significant relationship with the presence of fallen fruit. Two functional groups and two of the seven most common frugivore species assessed in the GLMs showed significant results with species-specific responses to altitude. Our findings provide a more detailed understanding of how frugivorous vertebrates cope with periods of water and fruit scarcity in lowland Amazon forests. PMID:28301589

Water availability not fruitfall modulates the dry season distribution of frugivorous terrestrial vertebrates in a lowland Amazon forest.

PubMed

Paredes, Omar Stalin Landázuri; Norris, Darren; Oliveira, Tadeu Gomes de; Michalski, Fernanda

2017-01-01

Terrestrial vertebrate frugivores constitute one of the major guilds in tropical forests. Previous studies show that the meso-scale distribution of this group is only weakly explained by variables such as altitude and tree basal area in lowland Amazon forests. For the first time we test whether seasonally limiting resources (water and fallen fruit) affect the dry season distribution in 25 species of terrestrial vertebrates. To examine the effects of the spatial availability of fruit and water on terrestrial vertebrates we used a standardized, regularly spaced arrangement of camera-traps within 25km2 of lowland Amazon forest. Generalized linear models (GLMs) were then used to examine the influence of four variables (altitude, distance to large rivers, distance to nearest water, and presence vs absence of fruits) on the number of photos on five functional groups (all frugivores, small, medium, large and very large frugivores) and on seven of the most abundant frugivore species (Cuniculus paca, Dasyprocta leporina, Mazama americana, Mazama nemorivaga, Myoprocta acouchy, Pecari tajacu and Psophia crepitans). A total of 279 independent photos of 25 species were obtained from 900 camera-trap days. For most species and three functional groups, the variation in the number of photos per camera was significantly but weakly explained by the GLMs (deviance explained ranging from 6.2 to 48.8%). Generally, we found that the presence of water availability was more important than the presence of fallen fruit for the groups and species studied. Medium frugivores, large-bodied frugivores, and two of the more abundant species (C. paca and P. crepitans) were recorded more frequently closer to water bodies; while none of the functional groups nor the most abundant species showed any significant relationship with the presence of fallen fruit. Two functional groups and two of the seven most common frugivore species assessed in the GLMs showed significant results with species-specific responses to altitude. Our findings provide a more detailed understanding of how frugivorous vertebrates cope with periods of water and fruit scarcity in lowland Amazon forests.

Seasonal and high-resolution variability in hydrochemistry of the Andes-Amazon

NASA Astrophysics Data System (ADS)

Burt, E.; West, A. J.

2017-12-01

Stream hydrochemistry acts as a record of integrated catchment processes such as the amount of time it takes precipitation to flow through the subsurface and become streamflow (water transit times), water-rock interaction and biogeochemical cycling. Although it is understood that sampling interval affects observed patterns in hydrochemistry, most studies collect samples on a weekly, bi-weekly or monthly schedule due to lack of resources or the difficulty of maintaining automated sampling devices. Here, we attempt to combine information from two sampling time scales, comparing a year-long hydrochemical time series to data from a recent sub-daily sampling campaign. Starting in April 2016, river, soil and rain waters have been collected every two weeks at five small catchments spanning the tropical Andes and Amazon - a natural laboratory for its gradients in topography, erosion rates, precipitation, temperature and flora. Between January and March, 2017, we conducted high frequency sampling for approximately one week at each catchment, sampling at least every four hours including overnight. We will constrain young water fractions (Kirchner, 2016) and storm water fluxes for the experimental catchments using stable isotopes of water as conservative tracers. Major element data will provide the opportunity to make initial constraints on geochemical and hydrologic coupling. Preliminary results suggest that in the Amazon, hydrochemistry patterns are dependent on sampling frequency: the seasonal cycle in stable isotopes of water is highly damped, while the high resolution sampling displays large variability. This suggests that a two-week sampling interval is not frequent enough to capture rapid transport of water, perhaps through preferential flow networks. In the Andes, stable isotopes of water are highly damped in both the seasonal and high resolution cycle, suggesting that the catchment behaves as a "well-mixed" system.

Distribution and availability of mercury and methylmercury in different waters from the Rio Madeira Basin, Amazon.

PubMed

Vieira, Miguel; Bernardi, José V E; Dórea, José G; Rocha, Bruno C P; Ribeiro, Romulo; Zara, Luis F

2018-04-01

Waters from the Amazon Basin have distinct physicochemical characteristics that can be optically classified as "black", "clear" and "white". We studied the distribution of total-Hg (THg) and methyl-Hg (MeHg) in these waters and respective suspended solids, sediment, phytoplankton, zooplankton, and benthic macroinvertebrates (BM) in the Madeira River Basin. Compared with the other types of water, the more acidic "black" kind had the highest THg and MeHg concentrations. The trend (black > clear > white) occurred for the concentrations of THg and MeHg in sediments and in the biotic compartment (plankton, macroinvertebrates). Organic Hg accounted for a small percentage (0.6-0.4%) of the THg in sediments but was highest in water (17-15%). For plankton and BM, the biota sediment accumulation factor (BSAFs) of MeHg (53-125) were greater than those of THg (4.5-15); however, the BSAF trend according to water type (black > clear > white) was only significant for MeHg. Sediment THg is correlated with all forms of Hg in biotic and abiotic matrices. The results indicate that water acidity in the Amazon is an important chemical characteristic in assessing Hg contamination of sediments and bioaccumulation in the aquatic food web. The differences in the BSAFs between THg and MeHg support the use of this factor for evaluating the bioaccumulation potential of sediment-bound Hg. The results add information critical to assessing environmental and health risks related to Hg methylation and potential fish-MeHg contamination, especially in tropical aquatic environments. Copyright © 2018 Elsevier Ltd. All rights reserved.

Elemental Mixing State of Aerosol Particles Collected in Central Amazonia during GoAmazon2014/15

DOE PAGES

Fraund, Matthew; Pham, Don; Bonanno, Daniel; ...

2017-09-15

Two complementary techniques, Scanning Transmission X-ray Microscopy/Near Edge Fine Structure spectroscopy (STXM/NEXAFS) and Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy (SEM/EDX), have been quantitatively combined to characterize individual atmospheric particles. This pair of techniques was applied to particle samples at three sampling sites (ATTO, ZF2, and T3) in the Amazon basin as part of the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) field campaign during the dry season of 2014. The combined data was subjected to k-means clustering using mass fractions of the following elements: C, N, O, Na, Mg, P, S, Cl, K, Ca, Mn, Fe, Ni, andmore » Zn. Cluster analysis identified 12 particle types, across different sampling sites and particle sizes. Samples from the remote Amazon Tall Tower Observatory (ATTO, also T0a) exhibited less cluster variety and fewer anthropogenic clusters than samples collected at the sites nearer to the Manaus metropolitan region, ZF2 (also T0t) or T3. Samples from the ZF2 site contained aged/anthropogenic clusters not readily explained by transport from ATTO or Manaus, possibly suggesting the effects of long range atmospheric transport or other local aerosol sources present during sampling. In addition, this data set allowed for recently established diversity parameters to be calculated. All sample periods had high mixing state indices (χ) that were >0.8. Two individual particle diversity (D i) populations were observed, with particles <0.5 μm having a D i of ~2.4 and >0.5 μm particles having a D i of ~3.6, which likely correspond to fresh and aged aerosols respectively. The diversity parameters determined by the quantitative method presented here will serve to aid in the accurate representation of aerosol mixing state, source apportionment, and aging in both less polluted and more industrialized environments in the Amazon Basin.« less

Elemental Mixing State of Aerosol Particles Collected in Central Amazonia during GoAmazon2014/15

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fraund, Matthew; Pham, Don; Bonanno, Daniel

Two complementary techniques, Scanning Transmission X-ray Microscopy/Near Edge Fine Structure spectroscopy (STXM/NEXAFS) and Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy (SEM/EDX), have been quantitatively combined to characterize individual atmospheric particles. This pair of techniques was applied to particle samples at three sampling sites (ATTO, ZF2, and T3) in the Amazon basin as part of the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) field campaign during the dry season of 2014. The combined data was subjected to k-means clustering using mass fractions of the following elements: C, N, O, Na, Mg, P, S, Cl, K, Ca, Mn, Fe, Ni, andmore » Zn. Cluster analysis identified 12 particle types, across different sampling sites and particle sizes. Samples from the remote Amazon Tall Tower Observatory (ATTO, also T0a) exhibited less cluster variety and fewer anthropogenic clusters than samples collected at the sites nearer to the Manaus metropolitan region, ZF2 (also T0t) or T3. Samples from the ZF2 site contained aged/anthropogenic clusters not readily explained by transport from ATTO or Manaus, possibly suggesting the effects of long range atmospheric transport or other local aerosol sources present during sampling. In addition, this data set allowed for recently established diversity parameters to be calculated. All sample periods had high mixing state indices (χ) that were >0.8. Two individual particle diversity (D i) populations were observed, with particles <0.5 μm having a D i of ~2.4 and >0.5 μm particles having a D i of ~3.6, which likely correspond to fresh and aged aerosols respectively. The diversity parameters determined by the quantitative method presented here will serve to aid in the accurate representation of aerosol mixing state, source apportionment, and aging in both less polluted and more industrialized environments in the Amazon Basin.« less

CryoSat-2 SAR and SARin Inland Water Heights from the CRUCIAL project

NASA Astrophysics Data System (ADS)

Benveniste, J.; Restano, M.; Ambrózio, A.; Moore, P.; Birkinshaw, S.

2017-12-01

CRUCIAL was an ESA/STSE funded project investigating innovative land and inland water applications from CryoSat-2 with a forward-look component to the Sentinel-3 and Jason-CS/Sentinel-6 missions. The high along-track sampling of CryoSat-2 in its SAR and SARin modes offers the opportunity to recover high frequency signals over inland waters. A methodology was developed to process the FBR L1A Doppler beams to form a waveform product using ground cell gridding, beam steering and beam stacking. Inland water heights from CryoSat-2 are derived by using a set of empirical retrackers formulated for inland water applications. Results of the processing strategy include a comparison of waveforms and heights from the burst echoes (80 m along-track) and from multi-look waveforms (320 m along-track). SAR and SARin FBR data are available for the Amazon, Brahmaputra and Mekong for 2011-2015. FBR SAR results are compared against stage data from the nearest gauge. Heights from Tonlé Sap are also compared against Jason-2 data from the United States Department of Agriculture. A strategy to select the number of multi-looks over rivers was designed based on the rms of heights across Tonlé Sap. Comparisons include results from the empirical retrackers and from waveforms and heights obtained via ESA's Grid Processing on Demand (G-POD/SARvatore) using the SAMOSA2 retracker. Results of FBR SARin processing for the Amazon and Brahmaputra are presented including comparison of heights from the two antennae, extraction of slope of the ground surface and validation against ground data where appropriate.

Environmental aspects related to tuberculosis and intestinal parasites in a low-income community of the Brazilian Amazon

PubMed Central

Cardoso, Biatriz Araújo; Fonseca, Fabio de Oliveira; de Moraes, Antonio Henrique Almeida; Martins, Ana Caroline Guedes Souza; Oliveira, Nissa Vilhena da Silva; Lima, Luana Nepomuceno Gondim Costa; Dias, George Alberto da Silva; Saad, Maria Helena Féres

2017-01-01

ABSTRACT We carried out a cross-sectional study from January to December 2015 on 1,425 inhabitants from a floating population in the Brazilian Amazon (Murinin district, Pará State) to describe the population-based prevalence of tuberculosis (TB) from 2011 to 2014, recent TB contacts (rCts) latently infected with Mycobacterium tuberculosis (LTBI) , the coverage of the local health network, socio-environmental factors, and frequency of intestinal parasitic infection (IPI). We found that the sanitary structure was inadequate, with latrines being shared with other rooms within the same accommodation; well water was the main source of water, and 48% of families had low incomes. The average rate of TB was 105/100, 000 inhabitants per year; one third of TB patients had been household contacts of infected individuals in the past, and 23% of rCts were LTBI. More than half (65%) of 44% of the stools examined (representing 76% of the housing) had IPIs; the highest prevalence was of fecal-oral transmitted protozoa (40%, Giardia intestinalis ), followed by soil-transmitted helminths (23%). TB transmission may be related to insufficient disease control of rCts, frequent relocation, and underreporting. Education, adopting hygienic habits, improving sanitation, provision of a treated water supply and efficient sewage system, further comprehensive epidemiological surveillance of those who enter and leave the community and resources for basic treatment of IPIs are crucial in combating the transmission of these neglected diseases. PMID:28793025

Environmental aspects related to tuberculosis and intestinal parasites in a low-income community of the Brazilian Amazon.

PubMed

Cardoso, Biatriz Araújo; Fonseca, Fabio de Oliveira; Moraes, Antonio Henrique Almeida de; Martins, Ana Caroline Guedes Souza; Oliveira, Nissa Vilhena da Silva; Lima, Luana Nepomuceno Gondim Costa; Dias, George Alberto da Silva; Saad, Maria Helena Féres

2017-08-07

We carried out a cross-sectional study from January to December 2015 on 1,425 inhabitants from a floating population in the Brazilian Amazon (Murinin district, Pará State) to describe the population-based prevalence of tuberculosis (TB) from 2011 to 2014, recent TB contacts (rCts) latently infected with Mycobacterium tuberculosis (LTBI) , the coverage of the local health network, socio-environmental factors, and frequency of intestinal parasitic infection (IPI). We found that the sanitary structure was inadequate, with latrines being shared with other rooms within the same accommodation; well water was the main source of water, and 48% of families had low incomes. The average rate of TB was 105/100, 000 inhabitants per year; one third of TB patients had been household contacts of infected individuals in the past, and 23% of rCts were LTBI. More than half (65%) of 44% of the stools examined (representing 76% of the housing) had IPIs; the highest prevalence was of fecal-oral transmitted protozoa (40%, Giardia intestinalis ), followed by soil-transmitted helminths (23%). TB transmission may be related to insufficient disease control of rCts, frequent relocation, and underreporting. Education, adopting hygienic habits, improving sanitation, provision of a treated water supply and efficient sewage system, further comprehensive epidemiological surveillance of those who enter and leave the community and resources for basic treatment of IPIs are crucial in combating the transmission of these neglected diseases.

Influence of the Amazon River on the Nd isotope composition of deep water in the western equatorial Atlantic during the Oligocene-Miocene transition

NASA Astrophysics Data System (ADS)

Stewart, Joseph A.; Gutjahr, Marcus; James, Rachael H.; Anand, Pallavi; Wilson, Paul A.

2016-11-01

Dissolved and particulate neodymium (Nd) are mainly supplied to the oceans via rivers, dust, and release from marine sediments along continental margins. This process, together with the short oceanic residence time of Nd, gives rise to pronounced spatial gradients in oceanic 143Nd/144Nd ratios (εNd). However, we do not yet have a good understanding of the extent to which the influence of riverine point-source Nd supply can be distinguished from changes in mixing between different water masses in the marine geological record. This gap in knowledge is important to fill because there is growing awareness that major global climate transitions may be associated not only with changes in large-scale ocean water mass mixing, but also with important changes in continental hydroclimate and weathering. Here we present εNd data for fossilised fish teeth, planktonic foraminifera, and the Fe-Mn oxyhydroxide and detrital fractions of sediments recovered from Ocean Drilling Project (ODP) Site 926 on Ceara Rise, situated approximately 800 km from the mouth of the River Amazon. Our records span the Mi-1 glaciation event during the Oligocene-Miocene transition (OMT; ∼23 Ma). We compare our εNd records with data for ambient deep Atlantic northern and southern component waters to assess the influence of particulate input from the Amazon River on Nd in ancient deep waters at this site. εNd values for all of our fish teeth, foraminifera, and Fe-Mn oxyhydroxide samples are extremely unradiogenic (εNd ≈ - 15); much lower than the εNd for deep waters of modern or Oligocene-Miocene age from the North Atlantic (εNd ≈ - 10) and South Atlantic (εNd ≈ - 8). This finding suggests that partial dissolution of detrital particulate material from the Amazon (εNd ≈ - 18) strongly influences the εNd values of deep waters at Ceara Rise across the OMT. We conclude that terrestrially derived inputs of Nd can affect εNd values of deep water many hundreds of kilometres from source. Our results both underscore the need for care in reconstructing changes in large-scale oceanic water-mass mixing using sites proximal to major rivers, and highlight the potential of these marine archives for tracing changes in continental hydroclimate and weathering.

On Dams in the Amazon Basin, Teleconnected Impacts, and Neighbors Unaware of the Damage to their Natural Resources and Assets.

NASA Astrophysics Data System (ADS)

Latrubesse, E. M.; Park, E.

2017-12-01

In a recent study, Latrubesse et al., (2017) demonstrated that the accumulated negative environmental effects of more than one hundred existing dams and at least 288 proposed dams, if constructed, will trigger massive hydrophysical and biotic disturbances that will affect the Amazon basin's floodplains, estuary and sediment plume. The authors introduced a Dam Environmental Vulnerability Index (DEVI) to quantify the current and potential impacts of dams in the basin. The current and potential vulnerabilities of different regions of the Amazon basin was assessed, and the results highlighted the need for a more efficient and integrative legal framework involving all nine countries of the basin in an anticipatory assessment to minimize the negative socio-environmental and biotic impacts of hydropower developments. Here we present expanded information on the potential impacts of dams in the lower Amazon and the northeast Atlantic coast of South America, and revisit our proposed integrative strategies for basin management which are based on the adaptation and functionality of the institutional and legal framework already existing in the Amazon countries. Participative strategies involving members from the Amazon Cooperation Treaty Organization (ACTO) countries, and additional members (for example, France), such as the creation of a basin committee -as defined by the Brazilian Law of Waters of Brazil-, and the creation of an Amazon Basin Panel allowing the participation of scientists that could have a policy-relevant role but should be not policy-prescriptive, are also discussed. ReferencesLatrubesse, E., Arima E. Dunne T., Park E., Baker V, Horta F.,Wight, C., Wittmann F., Zuanon, J., Baker P., Ribas C, Norgaard R., Filizola N., Ansar A., Flyvbjerg B., Stevaux, J. 2017. Damming the rivers of the Amazon basin. Nature, 546, 363-369.

Earth Observations taken by the Expedition 17 Crew

NASA Image and Video Library

2008-08-19

ISS017-E-013856 (19 Aug. 2008) --- Amazon River, Brazil is featured in this image photographed by an Expedition 17 crewmember on the International Space Station. This image shows the huge sunglint zone, common to oblique views from space, of the setting sun shining off the Amazon River and numerous lakes on its floodplain. About 150 kilometers of the sinuous Amazon course is shown here, as it appears about 1,000 kilometers from the Atlantic Ocean. The Uatuma River enters on the north side of the Amazon (top). A small side channel of the very large Madeira River enters the view from the left. Tupinambarama Island occupies the swampy wetlands between the Amazon and Madeira rivers. Sunglint images reveal great detail in waterbodies -- in this case the marked difference between the smooth outline of the Amazon and the jagged shoreline of the Uatuma River. The jagged shoreline results from valley sides being eroded in relatively hard rocks. The Uatuma River has since been dammed up by the sediment mass of the Amazon floodplain. Because the Amazon flows in its own soft sediment, its huge water discharge smooths the banks. Another dammed valley (known as a ria) is visible beneath the cirrus cloud of a storm (bottom). Although no smoke plumes from forest fires are visible in the view, two kinds of evidence show that there is smoke in the atmosphere. The coppery color of the sunglint is typically produced by smoke particles and other aerosols scattering yellow and red light. Second, a small patch of cloud (top right) casts a distinct shadow. The shadow, say scientists, is visible because so many particles in the surrounding sunlit parts of the atmosphere reflect light to the camera.

Precipitation Based Malaria Patterns in the Amazon -- Will Deforestation Alter Risk?

NASA Astrophysics Data System (ADS)

Olson, S. H.; Durieux, L.; Elguero, E.; Foley, J.; Gagnon, R.; Guegan, J.; Patz, J.

2007-12-01

The World Health Organization, estimates that forty-two percent of malaria cases are "associated with policies and practices regarding land use, deforestation, water resource management, settlement siting and modified house design". This estimate was drawn from expert opinion and studies performed at local scales, but little research has investigated the cumulative impacts of land use and land cover changes occurring in the Amazon Basin on malaria. Much less is understood about the impact of changing land use and subsequent precipitation regimes on malaria risk. To understand how land use practices may alter malaria patterns in the Basin we present an analysis of municipio (n=755) malaria case data and monthly precipitation patterns between 1996 and 1999. Climate data originated from the CRU TS 2.1 half-degree grid resolution climate data set. We present a hierarchical (random coefficients) log-linear Poisson model relating malaria incidence to precipitation for both municipos and states. At the Basin scale precipitation and cases show strong relationships. Precipitation and cases are asynchronous across the period of observation, but detailed inspection of states and individual municipios reveal geographic dependencies of precipitation and malaria incidence. Future research will link the patterns of precipitation and malaria to anticipated changes in climate from deforestation in the Basin.

Observational constraints indicate risk of drying in the Amazon basin.

PubMed

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

2011-03-29

Climate warming due to human activities will be accompanied by hydrological cycle changes. Economies, societies and ecosystems in South America are vulnerable to such water resource changes. Hence, water resource impact assessments for South America, and corresponding adaptation and mitigation policies, have attracted increased attention. However, substantial uncertainties remain in the current water resource assessments that are based on multiple coupled Atmosphere Ocean General Circulation models. This uncertainty varies from significant wetting to catastrophic drying. By applying a statistical method, we characterized the uncertainty and identified global-scale metrics for measuring the reliability of water resource assessments in South America. Here, we show that, although the ensemble mean assessment suggested wetting across most of South America, the observational constraints indicate a higher probability of drying in the Amazon basin. Thus, over-reliance on the consensus of models can lead to inappropriate decision making.

Hydrological Controls on Macrophyte Productivity in the Amazon Floodplain Wetlands

NASA Astrophysics Data System (ADS)

Silva, T. S.; Novo, E. M.; Melack, J. M.

2013-05-01

The Amazon River floodplain is an important source of atmospheric CO2 and CH4, but the relative contribution of allochthonous and autochthonous sources to floodplain emissions is still uncertain. Macrophytes comprise an important carbon source, growing during both low and high water conditions, and averaging 5,000 g.m-2.yr-1 in dry weight. The controls exerted by the annual flooding on macrophyte productivity result from two opposing mechanisms: the "horizontal expansion" of plant stands during low water levels and the stem elongation ("vertical growth") promoted by rising water levels. As studies suggest more frequent and intense droughts for the Amazon, determining how these mechanisms interact to control macrophyte net primary productivity (NPP) can lead to a better understanding of the effects of extreme hydrological conditions on autochthonous carbon fixation in the Amazon floodplain. Our study combines remote sensing estimates of macrophyte cover, in situ measurements of macrophyte biomass, historical water level records, and statistical modeling and simulation to answer 1) how plant horizontal expansion and vertical growth respond to inter-annual flooding variability, 2) how these responses modulate annual NPP, and 3) how climatic changes will affect the contribution of macrophytes to the carbon budget of the Amazon floodplain. Biomass data was collected along a stretch of the Lower Amazon Floodplain, at monthly intervals in 2004, and a time series of Radarsat-1 and EOS-MODIS images was acquired for the same area for the 2003-2005 period. Daily river stage data was acquired from the Brazilian National Water Agency (ANA) for the Óbidos station, covering the 1970 - 2011 period. Macrophyte cover was estimated for each available image in the series, using a multitemporal object-based image analysis algorithm. Empirical regression models were used to model the relationship between flood levels and both plant biomass and cover area, and combined into a semi-empirical growth model. Annual NPP was then predicted from daily biomass increments, spanning the 42-year hydrological data record. Resulting macrophyte cover maps had overall accuracies between 60% and 90%, and macrophyte cover area increased fourfold between high and low water seasons. Simulated NPP had marked variability, ranging from 1.06 (0.68, 1.70) Tg C yr-1 in 1980 to 1.63 (1.03, 2.63) Tg C yr-1 in 2009 for the entire mapped area.Values between parentheses show the 95% prediciton limits. Vertical growth was sensitive to extreme floods, but not to severe droughts, while horizontal expansion was affected by both extremely low and high water levels. The simulation revealed a complex pattern of interaction between the two components, indicating that extreme floods may result in larger increases in carbon fixation than extreme droughts. However, the results also suggested that overall flooding amplitude was positively correlated with simulated NPP values (r = 0.63, p > 0.001). An increasing trend in flood amplitude was observed in the hydrological record, which led to a small increase in annual NPP , of approximately 0.0008 TgC.yr-1 for the entire study region.

Terrestrial Water Flux Responses to Global Warming in Tropical Rainforest Area

NASA Astrophysics Data System (ADS)

Lan, C. W.; Lo, M. H.; Kumar, S.

2016-12-01

Precipitation extremes are expected to become more frequent in the changing global climate, which may considerably affect the terrestrial hydrological cycle. In this study, Coupled Model Intercomparison Project Phase 5 (CMIP5) archives have been examined to explore the changes in normalized terrestrial water fluxes (TWFn) (precipitation minus evapotranspiration minus total runoff, divided by the precipitation climatology) in three tropical rainforest areas: Maritime Continent, Congo, and Amazon. Results reveal that a higher frequency of intense precipitation events is predicted for the Maritime Continent in the future climate than in the present climate, but not for the Amazon or Congo rainforests. Nonlinear responses to extreme precipitation lead to a reduced groundwater recharge and a proportionately greater amount of direct runoff, particularly for the Maritime Continent, where both the amount and intensity of precipitation increase under global warming. We suggest that the nonlinear response is related to the existence of a higher near-surface soil moisture over the Maritime Continent than that over the Amazon and Congo rainforests. The wetter soil over the Maritime Continent also leads to an increased subsurface runoff. Thus, increased precipitation extremes and concomitantly reduced terrestrial water fluxes (TWF) lead to an intensified hydrological cycle for the Maritime Continent. This has the potential to result in a strong temporal heterogeneity in soil water distribution affecting the ecosystem of the rainforest region and increasing the risk of flooding and/or landslides.

Terrestrial water flux responses to global warming in tropical rainforest areas

NASA Astrophysics Data System (ADS)

Lan, Chia-Wei; Lo, Min-Hui; Chou, Chia; Kumar, Sanjiv

2016-05-01

Precipitation extremes are expected to become more frequent in the changing global climate, which may considerably affect the terrestrial hydrological cycle. In this study, Coupled Model Intercomparison Project Phase 5 archives have been examined to explore the changes in normalized terrestrial water fluxes (precipitation minus evapotranspiration minus total runoff, divided by the precipitation climatology) in three tropical rainforest areas: Maritime Continent, Congo, and Amazon. Results show that a higher frequency of intense precipitation events is predicted for the Maritime Continent in the future climate than in the present climate, but not for the Amazon or Congo rainforests. Nonlinear responses to extreme precipitation lead to a reduced groundwater recharge and a proportionately greater amount of direct runoff, particularly for the Maritime Continent, where both the amount and intensity of precipitation increase under global warming. We suggest that the nonlinear response is related to the existence of a higher near-surface soil moisture over the Maritime Continent than that over the Amazon and Congo rainforests. The wetter soil over the Maritime Continent also leads to an increased subsurface runoff. Thus, increased precipitation extremes and concomitantly reduced terrestrial water fluxes lead to an intensified hydrological cycle for the Maritime Continent. This has the potential to result in a strong temporal heterogeneity in soil water distribution affecting the ecosystem of the rainforest region and increasing the risk of flooding and/or landslides.

The spatial extent of change in tropical forest ecosystem services in the Amazon delta

NASA Astrophysics Data System (ADS)

de Araujo Barbosa, C. C.; Atkinson, P.; Dearing, J.

2014-12-01

Deltas hold major economic potential due their strategic location, close to seas and inland waterways, thereby supporting intense economic activity. The increasing pace of human development activities in coastal deltas over the past five decades has also strained environmental resources and produced extensive economic and sociocultural impacts. The Amazon delta is located in the Amazon Basin, North Brazil, the largest river basin on Earth and also one of the least understood. A considerable segment of the population living in the Amazon delta is directly dependent on the local extraction of natural resources for their livelihood. Areas sparsely inhabited may be exploited with few negative consequences for the environment. However, increasing pressure on ecosystem services is amplified by large fluxes of immigrants from other parts of the country, especially from the semi-arid zone in Northeast Brazil to the lowland forests of the Amazon delta. Here we present partial results from a bigger research project. Therefore, the focus will be on presenting an overview of the current state, and the extent of changes on forest related ecosystem services in the Amazon delta over the last three decades. We aggregated a multitude of datasets, from a variety of sources, for example, from satellite imagery such as the Advanced Very High Resolution Radiometer (AVHRR), the Global Inventory Modelling and Mapping Studies (GIMMS), the Moderate Resolution Imaging Spectroradiometer (MODIS), and climate datasets at meteorological station level from the Brazilian National Institute of Meteorology (INMET) and social and economic statistics data from the Brazilian Institute of Geography and Statistics (IBGE) and from the Brazilian Institute of Applied Economic Research (IPEA). Through analysis of socioeconomic and satellite earth observation data we were able to produce and present spatially-explicit information with the current state and transition in forest cover and its impacts to forest ecosystem services providing units in the Amazon delta.

Variability of carbon and water fluxes following climate extremes over a tropical forest in southwestern Amazonia.

PubMed

Zeri, Marcelo; Sá, Leonardo D A; Manzi, Antônio O; Araújo, Alessandro C; Aguiar, Renata G; von Randow, Celso; Sampaio, Gilvan; Cardoso, Fernando L; Nobre, Carlos A

2014-01-01

The carbon and water cycles for a southwestern Amazonian forest site were investigated using the longest time series of fluxes of CO2 and water vapor ever reported for this site. The period from 2004 to 2010 included two severe droughts (2005 and 2010) and a flooding year (2009). The effects of such climate extremes were detected in annual sums of fluxes as well as in other components of the carbon and water cycles, such as gross primary production and water use efficiency. Gap-filling and flux-partitioning were applied in order to fill gaps due to missing data, and errors analysis made it possible to infer the uncertainty on the carbon balance. Overall, the site was found to have a net carbon uptake of ≈5 t C ha(-1) year(-1), but the effects of the drought of 2005 were still noticed in 2006, when the climate disturbance caused the site to become a net source of carbon to the atmosphere. Different regions of the Amazon forest might respond differently to climate extremes due to differences in dry season length, annual precipitation, species compositions, albedo and soil type. Longer time series of fluxes measured over several locations are required to better characterize the effects of climate anomalies on the carbon and water balances for the whole Amazon region. Such valuable datasets can also be used to calibrate biogeochemical models and infer on future scenarios of the Amazon forest carbon balance under the influence of climate change.

Simulating hydrologic and hydraulic processes throughout the Amazon River Basin

USGS Publications Warehouse

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

2009-01-01

Presented here is a model framework based on a land surface topography that can be represented with various degrees of resolution and capable of providing representative channel/floodplain hydraulic characteristics on a daily to hourly scale. The framework integrates two models: (1) a water balance model (WBM) for the vertical fluxes and stores of water in and through the canopy and soil layers based on the conservation of mass and energy, and (2) a routing model for the horizontal routing of surface and subsurface runoff and channel and floodplain waters based on kinematic and diffusion wave methodologies. The WBM is driven by satellite-derived precipitation (TRMM_3B42) and air temperature (MOD08_M3). The model's use of an irregular computational grid is intended to facilitate parallel processing for applications to continental and global scales. Results are presented for the Amazon Basin over the period Jan 2001 through Dec 2005. The model is shown to capture annual runoff totals, annual peaks, seasonal patterns, and daily fluctuations over a range of spatial scales (>1, 000 to < 4·7M km2). For the period of study, results suggest basin-wide total water storage changes in the Amazon vary by approximately + /− 5 to 10 cm, and the fractional components accounting for these changes are: root zone soil moisture (20%), subsurface water being routed laterally to channels (40%) and channel/floodplain discharge (40%). Annual variability in monthly water storage changes by + /− 2·5 cm is likely due to 0·5 to 1 month variability in the arrival of significant rainfall periods throughout the basin.

Variability of Carbon and Water Fluxes Following Climate Extremes over a Tropical Forest in Southwestern Amazonia

PubMed Central

Zeri, Marcelo; Sá, Leonardo D. A.; Manzi, Antônio O.; Araújo, Alessandro C.; Aguiar, Renata G.; von Randow, Celso; Sampaio, Gilvan; Cardoso, Fernando L.; Nobre, Carlos A.

2014-01-01

The carbon and water cycles for a southwestern Amazonian forest site were investigated using the longest time series of fluxes of CO2 and water vapor ever reported for this site. The period from 2004 to 2010 included two severe droughts (2005 and 2010) and a flooding year (2009). The effects of such climate extremes were detected in annual sums of fluxes as well as in other components of the carbon and water cycles, such as gross primary production and water use efficiency. Gap-filling and flux-partitioning were applied in order to fill gaps due to missing data, and errors analysis made it possible to infer the uncertainty on the carbon balance. Overall, the site was found to have a net carbon uptake of ≈5 t C ha−1 year−1, but the effects of the drought of 2005 were still noticed in 2006, when the climate disturbance caused the site to become a net source of carbon to the atmosphere. Different regions of the Amazon forest might respond differently to climate extremes due to differences in dry season length, annual precipitation, species compositions, albedo and soil type. Longer time series of fluxes measured over several locations are required to better characterize the effects of climate anomalies on the carbon and water balances for the whole Amazon region. Such valuable datasets can also be used to calibrate biogeochemical models and infer on future scenarios of the Amazon forest carbon balance under the influence of climate change. PMID:24558378

Methylmercury Modulation in Amazon Rivers Linked to Basin Characteristics and Seasonal Flood-Pulse.

PubMed

Kasper, Daniele; Forsberg, Bruce R; Amaral, João H F; Py-Daniel, Sarah S; Bastos, Wanderley R; Malm, Olaf

2017-12-19

We investigated the impact of the seasonal inundation of wetlands on methylmercury (MeHg) concentration dynamics in the Amazon river system. We sampled 38 sites along the Solimões/Amazon and Negro rivers and their tributaries during distinct phases of the annual flood-pulse. MeHg dynamics in both basins was contrasted to provide insight into the factors controlling export of MeHg to the Amazon system. The export of MeHg by rivers was substantially higher during high-water in both basins since elevated MeHg concentrations and discharge occurred during this time. MeHg concentration was positively correlated to %flooded area upstream of the sampling site in the Solimões/Amazon Basin with the best correlation obtained using 100 km buffers instead of whole basin areas. The lower correlations obtained with the whole basin apparently reflected variable losses of MeHg exported from upstream wetlands due to demethylation, absorption, deposition, and degradation before reaching the sampling site. A similar correlation between %flooded area and MeHg concentrations was not observed in the Negro Basin probably due to the variable export of MeHg from poorly drained soils that are abundant in this basin but not consistently flooded.

Lidar observed seasonal variation of vertical canopy structure in the Amazon evergreen forests

NASA Astrophysics Data System (ADS)

Tang, H.; Dubayah, R.

2017-12-01

Both light and water are important environmental factors governing tree growth. Responses of tropical forests to their changes are complicated and can vary substantially across different spatial and temporal scales. Of particular interest is the dry-season greening-up of Amazon forests, a phenomenon undergoing considerable debates whether it is real or a "light illusion" caused by artifacts of passive optical remote sensing techniques. Here we analyze seasonal dynamic patterns of vertical canopy structure in the Amazon forests using lidar observations from NASA's Ice, Cloud, and and land Elevation Satellite (ICESat). We found that the net greening of canopy layer coincides with the wet-to-dry transition period, and its net browning occurs mostly at the late dry season. The understory also shows a seasonal cycle, but with an opposite variation to canopy and minimal correlation to seasonal variations in rainfall or radiation. Our results further suggest a potential interaction between canopy layers in the light regime that can optimize the growth of Amazon forests during the dry season. This light regime variability that exists in both spatial and temporal domains can better reveal the dry-season greening-up phenomenon, which appears less obvious when treating the Amazon forests as a whole.

On the offshore dispersal of the Amazon's Plume in the North Atlantic: Comments on the paper by A. Longhurst, ``Seasonal cooling and blooming in tropical oceans''

NASA Astrophysics Data System (ADS)

Muller-Karger, F. E.; Richardson, P. L.; Mcgillicuddy, D.

1995-11-01

Coastal Zone Color Scanner (CZCS) satellite images show extensive plumes of discolored water extending from South America into the western tropical Atlantic. The most conspicuous plumes originate at the mouths of the Amazon and Orinoco Rivers, and plumes originating at smaller rivers can also be seen from space. In a recent paper by Longhurst (1993), the plume associated with the Amazon River was attributed to phytoplankton blooms stimulated by nutrients supplied via eddy upwelling. We revisit the argument that this plume is of riverine origin, and offer evidence that material present near continental margins can be advected offshore and trace circulation patterns in the adjacent ocean.

Mouths of the Amazon River, Brazil, South America

NASA Technical Reports Server (NTRS)

1991-01-01

Huge sediment loads from the interior of the country flow through the Mouths of the Amazon River, Brazil (0.5S, 50.0W). The river current carries hundreds of tons of sediment through the multiple outlets of the great river over 100 miles from shore before it is carried northward by oceanic currents. The characteristic 'fair weather cumulus' pattern of low clouds over the land but not over water may be observed in this scene.

Mouths of the Amazon River, Brazil, South America

NASA Image and Video Library

1991-08-11

Huge sediment loads from the interior of the country flow through the Mouths of the Amazon River, Brazil (0.5S, 50.0W). The river current carries hundreds of tons of sediment through the multiple outlets of the great river over 100 miles from shore before it is carried northward by oceanic currents. The characteristic "fair weather cumulus" pattern of low clouds over the land but not over water may be observed in this scene.

River mixing in the Amazon as a driver of concentration-discharge relationships

NASA Astrophysics Data System (ADS)

Moquet, Jean-Sébastien; Bouchez, Julien; Carlo Espinoza, Jhan; Martinez, Jean-Michel; Guyot, Jean-Loup; Lagane, Christelle; Filizola, Naziano; Aniceto, Keila; Noriega, Luis; Hidalgo Sanchez, Liz; Pombosa, Rodrigo; Fraizy, Pascal; Santini, William; Timouk, Franck; Vauchel, Philippe

2017-04-01

Large hydrological systems such as continental-scale river basins aggregate water from compositionally different tributaries. Here we explore how such aggregation can affect solute concentration-discharge (C-Q) relationships and thus obscure the message carried by these relationships in terms of weathering properties of the Critical Zone. We compute 10 day-frequency time series of Q and major solute (Si, Ca2+, Mg2+, K+, Na+, Cl-, SO42-) C and fluxes (F) for 13 gauging stations of the SNO-HYBAM Monitoring Program (Geodynamical, hydrological and Biogeochemical control of erosion/weathering and material transport in the Amazon, Orinoco and Congo basins) located throughout the Amazon basin, the largest river basin in the world. Concentration-discharge relationships vary in a systematic manner, shifting for most solutes from a nearly "chemostatic" behavior (constant C) at the Andean mountain front to a more "dilutional" pattern (negative C-Q relationship) towards the system mouth. Associated to this shift in trend is a shift in shape: C-Q hysteresis becomes more prominent at the most downstream stations. A simple model of tributary mixing allows us to identify the important parameters controlling C-Q trends and shapes in the mixture, and we show that for the Amazon case, the model results are in qualitative agreement with the observations. Altogether, this study suggests that mixing of water and solutes between different flowpaths leads to altered C-Q relationships.

Oxidation and reduction rates for organic carbon in the Amazon mainstream tributary and floodplain, inferred from distributions of dissolved gases

NASA Technical Reports Server (NTRS)

Richey, Jeffrey E.; Devol, Allan H.; Wofsy, Steven C.; Victoria, Reynaldo; Riberio, Maria N. G.

1986-01-01

Concentrations of CO2, O2, CH4, and N2O in the Amazon River system reflect an oxidation-reduction sequence in combination with physical mixing between the floodplain and the mainstem. Concentrations of CO2 ranged from 150 microM in the Amazon mainstem to 200 to 300 microM in aerobic waters of the floodplain, and up to 1000 microM in oxygen-depleted environments. Apparent oxygen utilization (AOU) ranged from 80 to 250 microM. Methane was highly supersaturated, with concentrations ranging from 0.06 microM in the mainstem to 100 microM on the floodplain. Concentrations of N2O were slightly supersaturated in the mainstem, but were undersaturated on the floodplain. Fluxes calculated from these concentrations indicated decomposition of 1600 g C sq m y(-1) of organic carbon in Amazon floodplain waters. Analysis of relationships between CH4, O2, and CO2 concentrations indicated that approximately 50 percent of carbon mineralization on the floodplain is anaerobic, with 20 percent lost to the atmoshphere as CH4. The predominance of anaerobic metabolism leads to consumption of N2O on the flood plane. Elevated concentrations of CH4 in the mainstem probably reflect imput from the floodplain, while high levels of CO2 in the mainstem are derived from a combination of varzea drainage and in situ respiration.

Atmospheric moisture transport and fresh water flux over oceans derived from spacebased sensors

NASA Technical Reports Server (NTRS)

Liu, W. T.; Tang, W.

2001-01-01

preliminary results will be shown to demonstrate the application of spacebased IMT and fresh water flux in ocean-atmosphere-land interaction studies, such as the hydrologica balance on Amazon rainfall and Indian monsoon.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dubey, Manvendra; Parket, Harrison; Myers, Katherine

Forests soak up 25% of the carbon dioxide (CO2) emitted by anthropogenic fossil energy use (10 Gt C y-1), moderating its atmospheric accumulation. How this terrestrial CO2 uptake will evolve with climate change in the 21st Century is largely unknown. Rainforests are the most active ecosystems, with the Amazon basin storing 120 Gt C as biomass and exchanging 18 Gt C y-1 of CO2 via photosynthesis and respiration and fixing carbon at 2-3 kg C m-2 y-1. Furthermore, the intense hydrologic and carbon cycles are tightly coupled in the Amazon where about half of the water is recycled by evapotranspirationmore » and the other half imported from the ocean by Northeasterly trade winds. Climate models predict a drying in the Amazon with reduced carbon uptake while observationally guided assessments indicate sustained uptake. We set out to resolve this huge discrepancy in the size and sign of the future Amazon carbon cycle by performing the first simultaneous regional-scale high-frequency measurements of atmospheric CO2, H2O, HOD, CH4, N2O, and CO at the T3 site in Manacupuru, Brazil, as part of DOE's GoAmazon 2014/15 project. Our data will be used to inform and develop DOE's Community Land Model (CLM) on the tropical carbon-water couplings at the appropriate grid scale (10-50 km). Our measurements will also validate the CO2 data from Japan's Greenhouse gases Observing Satellite (GOSAT) and NASA's Orbiting Carbon Observatory (OCO)-2 satellite (launched in July, 2014). Our data addresses these science questions: 1. How does ecosystem heterogeneity and climate variability influence the rainforest carbon cycle? 2. How well do current tropical ecosystem models simulate the observed regional carbon cycle? 3. Does nitrogen deposition (from the Manaus, Brazil, plume) enhance rainforest carbon uptake?« less

Description of Trichophoromyia ruifreitasi, a new phlebotomine species (Diptera, Psychodidae) from Acre State, Brazilian Amazon

PubMed Central

de Oliveira, Arley Faria José; Teles, Carolina Bioni Garcia; Medeiros, Jansen Fernandes; Camargo, Luís Marcelo Aranha; Pessoa, Felipe Arley Costa

2015-01-01

Abstract Trichophoromyia ruifreitasi sp. n. is described as a new species of sand fly from the genus Trichophoromyia Barretto. This description is supported with illustrations and photographs that detail the morphological characteristics of male specimens collected in the municipality of Assis Brasil, Acre State, Brazilian Amazon. This species is similar to Trichophoromyia auraensis (Mangabeira), but the two species can be easily differentiated by the distribution of setae on their parameres, and by the presence of a dorsal lobe in the parameres of the new species. PMID:26487825

Description of Trichophoromyia ruifreitasi, a new phlebotomine species (Diptera, Psychodidae) from Acre State, Brazilian Amazon.

PubMed

de Oliveira, Arley Faria José; Teles, Carolina Bioni Garcia; Medeiros, Jansen Fernandes; Camargo, Luís Marcelo Aranha; Pessoa, Felipe Arley Costa

2015-01-01

Trichophoromyia ruifreitasi sp. n. is described as a new species of sand fly from the genus Trichophoromyia Barretto. This description is supported with illustrations and photographs that detail the morphological characteristics of male specimens collected in the municipality of Assis Brasil, Acre State, Brazilian Amazon. This species is similar to Trichophoromyia auraensis (Mangabeira), but the two species can be easily differentiated by the distribution of setae on their parameres, and by the presence of a dorsal lobe in the parameres of the new species.

Methane and Carbon Dioxide Concentrations and Fluxes in Amazon Floodplains

NASA Astrophysics Data System (ADS)

Melack, J. M.; MacIntyre, S.; Forsberg, B.; Barbosa, P.; Amaral, J. H.

2016-12-01

Field studies on the central Amazon floodplain in representative aquatic habitats (open water, flooded forests, floating macrophytes) combine measurements of methane and carbon dioxide concentrations and fluxes to the atmosphere over diel and seasonal times with deployment of meteorological sensors and high-resolution thermistors and dissolved oxygen sondes. A cavity ringdown spectrometer is used to determine gas concentrations, and floating chambers and bubble collectors are used to measure fluxes. To further understand fluxes, we measured turbulence as rate of dissipation of turbulent kinetic energy based on microstructure profiling. These results allow calculations of vertical mixing within the water column and of air-water exchanges using surface renewal models. Methane and carbon dioxide fluxes varied as a function of season, habitat and water depth. High CO2 fluxes at high water are related to high pCO2; low pCO2 levels at low water result from increased phytoplankton uptake. CO2 fluxes are highest at turbulent open water sites, and pCO2 is highest in macrophyte beds. Fluxes and pCH4 are high in macrophyte beds.

Amazon River carbon dioxide outgassing fuelled by wetlands.

PubMed

Abril, Gwenaël; Martinez, Jean-Michel; Artigas, L Felipe; Moreira-Turcq, Patricia; Benedetti, Marc F; Vidal, Luciana; Meziane, Tarik; Kim, Jung-Hyun; Bernardes, Marcelo C; Savoye, Nicolas; Deborde, Jonathan; Souza, Edivaldo Lima; Albéric, Patrick; Landim de Souza, Marcelo F; Roland, Fabio

2014-01-16

River systems connect the terrestrial biosphere, the atmosphere and the ocean in the global carbon cycle. A recent estimate suggests that up to 3 petagrams of carbon per year could be emitted as carbon dioxide (CO2) from global inland waters, offsetting the carbon uptake by terrestrial ecosystems. It is generally assumed that inland waters emit carbon that has been previously fixed upstream by land plant photosynthesis, then transferred to soils, and subsequently transported downstream in run-off. But at the scale of entire drainage basins, the lateral carbon fluxes carried by small rivers upstream do not account for all of the CO2 emitted from inundated areas downstream. Three-quarters of the world's flooded land consists of temporary wetlands, but the contribution of these productive ecosystems to the inland water carbon budget has been largely overlooked. Here we show that wetlands pump large amounts of atmospheric CO2 into river waters in the floodplains of the central Amazon. Flooded forests and floating vegetation export large amounts of carbon to river waters and the dissolved CO2 can be transported dozens to hundreds of kilometres downstream before being emitted. We estimate that Amazonian wetlands export half of their gross primary production to river waters as dissolved CO2 and organic carbon, compared with only a few per cent of gross primary production exported in upland (not flooded) ecosystems. Moreover, we suggest that wetland carbon export is potentially large enough to account for at least the 0.21 petagrams of carbon emitted per year as CO2 from the central Amazon River and its floodplains. Global carbon budgets should explicitly address temporary or vegetated flooded areas, because these ecosystems combine high aerial primary production with large, fast carbon export, potentially supporting a substantial fraction of CO2 evasion from inland waters.

Animal Movement and Establishment of Vaccinia Virus Cantagalo Strain in Amazon Biome, Brazil

PubMed Central

Quixabeira-Santos, Jociane Cristina; Medaglia, Maria Luiza G.; Pescador, Caroline A.

2011-01-01

To understand the emergence of vaccinia virus Cantagalo strain in the Amazon biome of Brazil, during 2008–2010 we conducted a molecular and epidemiologic survey of poxvirus outbreaks. Data indicate that animal movement was the major cause of virus dissemination within Rondônia State, leading to the establishment and spread of this pathogen. PMID:21470472

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pedlowski, M.A.; Dale, V.H.

Road development and colonization projects have brought about wide-scale deforestation in the Brazilian Amazon. The state of Rondonia, located in the western Amazon Basin, best exemplifies the problems related to land-use changes because it has the highest rates of deforestation in the Amazon Basin. In order to identify the main land-use practices in Rondonia, interviews with local farmers were carried out in the central part of Rondonia, in the PIC (Integrated Colonization Project) Ouro Preto do Oeste. This is the oldest colonization project in the state. The governmental colonization programs attracted migrants to the area through the construction of roadsmore » and infrastructure necessary for the colonists to occupy the land for agricultural practices. The interviews were done on lots of the PIC Ouro Preto and in PAD Urupa to define the background of the colonists, their land-use practices, their economic situation, and their relationships with governmental institutions.« less

Honors

NASA Astrophysics Data System (ADS)

2013-11-01

The recently released list of 2013-2014 Fulbright Scholars includes 9 AGU members working on diverse topics. They include Michael Coe, senior scientist/coordinator of the Amazon group at the Woods Hole Research Center, whose topic is "Agricultural expansion in the Brazilian Cerrado and consequences for the water cycle"; Benjamin Crosby, associate professor, Department of Geosciences, Idaho State University, on the topic "Taking the pulse of Chilean rivers: Enhancing educational and academic opportunities in a time of rapid change"; David Fitzjarrald, senior research associate, Atmospheric Sciences Research Center, State University of New York at Albany, on the topic "Landscape heterogeneity and Amazonian mesoclimate: Fostering critical understanding of observations and model output"; and Syed Hasan, professor of geology, Department of Geosciences, University of Missouri-Kansas City, who will be teaching courses in waste management.

Predicting the response of the Amazon rainforest to persistent drought conditions under current and future climates: a major challenge for global land surface models

NASA Astrophysics Data System (ADS)

Joetzjer, E.; Delire, C.; Douville, H.; Ciais, P.; Decharme, B.; Fisher, R.; Christoffersen, B.; Calvet, J. C.; da Costa, A. C. L.; Ferreira, L. V.; Meir, P.

2014-08-01

While a majority of Global Climate Models project dryer and longer dry seasons over the Amazon under higher CO2 levels, large uncertainties surround the response of vegetation to persistent droughts in both present-day and future climates. We propose a detailed evaluation of the ability of the ISBACC Land Surface Model to capture drought effects on both water and carbon budgets, comparing fluxes and stocks at two recent ThroughFall Exclusion (TFE) experiments performed in the Amazon. We also explore the model sensitivity to different Water Stress Function (WSF) and to an idealized increase in CO2 concentration and/or temperature. In spite of a reasonable soil moisture simulation, ISBACC struggles to correctly simulate the vegetation response to TFE whose amplitude and timing is highly sensitive to the WSF. Under higher CO2 concentration, the increased Water Use Efficiency (WUE) mitigates the ISBACC's sensitivity to drought. While one of the proposed WSF formulation improves the response of most ISBACC fluxes, except respiration, a parameterization of drought-induced tree mortality is missing for an accurate estimate of the vegetation response. Also, a better mechanistic understanding of the forest responses to drought under a warmer climate and higher CO2 concentration is clearly needed.

Cloudiness over the Amazon rainforest: Meteorology and thermodynamics

NASA Astrophysics Data System (ADS)

Collow, Allison B. Marquardt; Miller, Mark A.; Trabachino, Lynne C.

2016-07-01

Comprehensive meteorological observations collected during GOAmazon2014/15 using the Atmospheric Radiation Measurement Mobile Facility no. 1 and assimilated observations from the Modern-Era Retrospective Analysis for Research and Applications, Version 2 are used to document the seasonal cycle of cloudiness, thermodynamics, and precipitation above the Amazon rainforest. The reversal of synoptic-scale vertical motions modulates the transition between the wet and dry seasons. Ascending moist air during the wet season originates near the surface of the Atlantic Ocean and is advected into the Amazon rainforest, where it experiences convergence and, ultimately, precipitates. The dry season is characterized by weaker winds and synoptic-scale subsidence with little or no moisture convergence accompanying moisture advection. This combination results in the drying of the midtroposphere during June through October as indicated by a decrease in liquid water path, integrated water, and the vertical profile of water vapor mixing ratio. The vertical profile of cloud fraction exhibits a relatively consistent decline in cloud fraction from the lifting condensation level (LCL) to the freezing level where a minimum is observed, unlike many other tropical regions. Coefficients of determination between the LCL and cloud fractional coverage suggest a relatively robust relationship between the LCL and cloudiness beneath 5 km during the dry season (R2 = 0.42) but a weak relationship during the wet season (0.12).

Divergent biophysical controls of aquatic CO2 and CH4 in the World's two largest rivers.

PubMed

Borges, Alberto V; Abril, Gwenaël; Darchambeau, François; Teodoru, Cristian R; Deborde, Jonathan; Vidal, Luciana O; Lambert, Thibault; Bouillon, Steven

2015-10-23

Carbon emissions to the atmosphere from inland waters are globally significant and mainly occur at tropical latitudes. However, processes controlling the intensity of CO2 and CH4 emissions from tropical inland waters remain poorly understood. Here, we report a data-set of concurrent measurements of the partial pressure of CO2 (pCO2) and dissolved CH4 concentrations in the Amazon (n = 136) and the Congo (n = 280) Rivers. The pCO2 values in the Amazon mainstem were significantly higher than in the Congo, contrasting with CH4 concentrations that were higher in the Congo than in the Amazon. Large-scale patterns in pCO2 across different lowland tropical basins can be apprehended with a relatively simple statistical model related to the extent of wetlands within the basin, showing that, in addition to non-flooded vegetation, wetlands also contribute to CO2 in river channels. On the other hand, dynamics of dissolved CH4 in river channels are less straightforward to predict, and are related to the way hydrology modulates the connectivity between wetlands and river channels.

The effect of topography and rock type on soil cation contents and stream solute and phosphorus concentrations of streams in the southwestern Brazilian Amazon basin.

NASA Astrophysics Data System (ADS)

Biggs, T. W.; Dunne, T.; Holmes, K.; Martinelli, L. A.

2001-12-01

Topography plays an important role in determining soil properties, stream solute concentrations and landscape denudation rates. Stallard (1985) suggested that catchment denudation rates should depend on soil thickness. Areas with low slopes are limited by the rate of transport of sediment, and typically contain thick soils that prevent interaction of stream waters with underlying bedrock [Stallard 1985]. Steep areas typically have thin soils, but a lower hydrologic residence time that may prevent soil water from coming into thermodynamic equilibrium with the soil-rock complex. In a survey of streams in the Brazilian Amazon basin, Biggs et al. (2001) found that stream solute concentrations correlate with soil cation contents in the humid tropics, but the mechanism underlying the correlation has not been determined. We combine chemical analyses of water samples from ~40 different streams with soil surveys, geology maps, and a 100m resolution DEM to examine the relationship between topography, rock type, soil cation contents, and stream solute concentrations in the Brazilian Amazon state of Rondônia. The basins are all more than 60% forested at the time of stream sampling and lie on granite-gneiss rocks, tertiary sediments, or sandstone. The catchment-averaged slope correlates positively with both soil cation contents and stream concentrations of P, Na, Ca, Mg, K, Si, ANC, and pH. Though we have no data about the relationship between soil depth and average slope, we assume an inverse correlation, so the data demonstrates that thick soils yield lower solute concentrations. Stream concentrations of Ca, Mg, ANC and pH reach a maximum at intermediate average slopes (3 degrees), suggesting that denudation rates may increase with slope up to a maximum, when the catchment becomes limited by the weathering rate of the basement rock. Catchments on mica-schists or mafic rocks have low average slopes and higher concentrations of Ca, Mg, Si, ANC, and pH than catchments on granite-gneiss, tertiary sediments or sandstone.

Using LandSat and SRTM datasets to develop relationships for estimating bankfull channel widths in the Amazon Basin

NASA Astrophysics Data System (ADS)

Gummadi, V.; He, Y.; Beighley, E. R.

2007-12-01

Modeling fine scale spatial and temporal processes of the hydrologic cycle over continental to global extents is vital for assessing the potential impacts of climate and land use change on global water resources and related systems. Significant advancement in understanding and predicting the magnitude, trend, timing and partitioning of terrestrial water stores and fluxes requires the development of methodologies and knowledge for extracting representative hydraulic geometries from remote sensing data products and field data, suitable for estimating inundation characteristics and water storage changes which are limited for much of the globe. In this research, relationships between channel and floodplain widths and spatial drainage characteristics are developed for the Amazon Basin. Channel and floodplain widths were measured using SRTM data and LandSat TM/ETM imagery at 510 sites. The study sites were selected based on the Pfafstetter decomposition methodology which provides an irregular model grid based on repeatedly subdividing landscape units into nine subunits consisting of basins and interbasins. The selected sites encompass all possible combinations of Pfafstetter modeling units (ex., basins of interbasins, interbasins of basins, etc.). The 510 study sites are within the Amazon Basin with drainage areas ranging 10 to 5.4 million sq km and mean watershed ground slopes ranging from 0.4 and 30 percent. Preliminary results indicate that channel widths can be predicted using drainage area and mean watershed slope (R2 = 0.85). Floodplain widths can be predicted using channel width and the local slope (R2 = 0.70). Using the Purus watershed, a sub-basin to the Amazon (350,000 sq km), effects of channel and floodplain widths on simulated hydrographs are presented.

Neisseria meningitidis: a neglected cause of infectious haemorrhagic fever in the amazon rainforest.

PubMed

Barroso, David E; Silva, Luciete A

2007-12-01

Neisseria meningitidis has not been seen as a significant cause of infectious haemorrhagic fever in the Amazon inlands; most reported cases are from the city of Manaus, the capital of the State of Amazonas. This picture is sustained by the lack of reliable microbiology laboratories, the perception of the health care workers, and the difficult to reach medical assistance; thus the number of confirmed cases is even lower with no reference of the strains phenotype. We report here the investigation of a case of suspected meningococcemia and his close contacts in a rural community in the Coari Lake, up the Amazon River.

Repeat-Pass Multi-Temporal Interferometric SAR Coherence Variations with Amazon Floodplain and Lake Habitats

NASA Astrophysics Data System (ADS)

Jung, H.; Alsdorf, D.

2006-12-01

Monitoring discharge in the main channels of rivers and upland tributaries as well as storage changes in floodplain lakes is necessary for understanding flooding hazards, methane production, sediment transport, and nutrient exchange. Interferometric processing of synthetic aperture radar (SAR) data may enable hydrologists to detect environmental and ecological changes in hydrological systems over space and time. An aim of our experiments is to characterize interferometric SAR coherence variations that occur in Amazon aquatic habitats. We analyze coherence variations in JERS-1 data at three central Amazon sites; Lake Balbina, the Cabaliana floodplain, and the confluence of the Purus and Amazon rivers. Because radar pulse interactions with inundated vegetation typically follow a double-bounce travel path which returns energy to the antenna, coherence will vary with vegetation type, physical baseline, and temporal baseline. Balbina's vegetation consists mostly of forest and inundated trunks of dead, leafless trees as opposed to Cabaliana and Amazon- Purus (dominated by flooded forests), thus it serves to isolate the vegetation signal. Coherence variations with baselines were determined from 253 interferograms at Balbina, 210 at Calbaliana, and 153 at Purus. The average temporal and perpendicular baselines (mean std.) are 574 394 days and 1708 1159 m at Balbina, 637 435 days and 1381 981 m at Cabaliana, and 587 425 days and 1430 964 m at Purus. Balbina has a stronger coherence than either Cabaliana or Amazon-Purus. With results of Mann-Whitney statistical tests, Balbina has a difference between terre-firme and flooded coherence values plotted with perpendicular baseline but Cabaliana and Amazon-Purus do not show this difference. Balbina has a linearly decreasing trend in coherence plotted with temporal baseline whereas Cabaliana and Amazon-Purus have a steep drop-off, non- linear change. A strong annual periodicity is evident on power spectrums of the coherence values for Cabaliana and Amazon-Purus, but not in Balbina and is likely an indicator of the annual Amazon flood wave. Each ecological habitat is delineated in the Balbina coherence values plotted with temporal baseline, but only during high water and time-periods less than 2 years is such delineation visible in the Cabaliana and Amazon-Purus regions. Taken together, these observations suggest terre-firme does not have a seasonal variation whereas flooded areas vary with the season.

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

DOE PAGES

Luo, Xiangyu; Li, Hong -Yi; Leung, L. Ruby; ...

2017-03-23

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Xiangyu; Li, Hong -Yi; Leung, L. Ruby

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

Modern Environmental Changes on Amapa Coastal Plain under Amazon River Influence

NASA Astrophysics Data System (ADS)

Santos, V. F.; Figueiredo, A. G.; Silveira, O. M.; Polidori, L.

2007-05-01

The Amazonian coastal environment is very dynamic compared to other coasts. It is situated at the edge of the Earth's largest forest, and is segmented by fluvial systems, with the biggest being the Amazon River. The rivers are particularly influenced by the Intertropical Convergence Zone (ITCZ), which controls the water and particle discharge, and the flooding regime. Moderate and strong El Nino conditions correlate with low-precipitation periods, and La Nina events cause precipitation to increase. These variables and others related to the Amazon dispersal system create an interesting area for the study of global and regional environmental changes. The Araguari River floodplain on the Amapa coast is influenced by natural processes of global scale such as ENSO events and ITCZ, and by local processes such as Amazon River discharge, tides and tidal bore (pororoca). Anthropogenic processes such as extensive water-buffalo farming also promote environmental changes. Time- series analyses of remote sensing images and suspended sediment have shown that the maximum turbidity zone inside Araguari River is related to the pororoca phenomenon. The pororoca remobilizes sediment from the river bottom and margins, developing sediment suspension >15 g/l as it passes - creating fluid muds. The pororoca also introduces Amazon- and shelf-derived sediment into the Araguari estuary. Measurements during eight spring-tide cycles indicate erosion of 3 cm of consolidated mud and deposition of 1 cm. The pororoca also influences the remobilization and cycling of nutrients and consequently affects the distribution of benthic organisms, including benthonic foraminifera and thecamoebians. For more than a century, the coastal plain has had water-buffalo farming (>42,000 animals today), which modifies the drainage system and affects sedimentary processes. Areas with more buffalo trails have higher suspended-sediment concentration (SSC) during the dry season and lower SSC during the rainy season. This relationship is reversed in drainages without the influence of the herd. The development of small channels, one meter deep by one meter wide, induced by the buffalos can evolve into a large drainage network in a short period of time. The Santana Creek started as a buffalo trail and in three decades it evolved into a network with a main channel 200 m wide and 6 km long. Despite the Amazon River having the largest influence in the region, the Araguari River also has a considerable water discharge of 2.4x103 m3/s and particulate discharge of 7x105 tons/y, and is able to impose changes to the Amapa coastal environments and inner shelf. The natural closure of the Araguari north arm during middle of the 19th century has induced the development of a wide coastal plain in the Cape Norte region, and decreased fresh water to the Carapaporis channel. On the other hand, deforestation for farm development and buffalo farming has influenced the hydrologic regime, sediment and nutrient balance.

Key to Plecoptera nymphs from the Brazilian Amazon (Insecta).

PubMed

Ribeiro, José Moacir Ferreira; Gorayeb, Inocêncio DE Sousa

2016-12-19

Nymphs of 22 species of Plecoptera from the Brazilian Amazon are keyed and illustrated to enhance their usefulness as water quality indicator taxa. Four described species of Anacroneuria, two species of Macrogynoplax, and two species of Enderleina have been associated with adults: Anacroneuria marlieri, A. manauensis, A. minuta, A. singularis, M. delicata, M. pulchra, E. froehlichi, and E. flinti. Nymphs of 14 additional morphospecies not yet associated with adults are included. Characters of the head, pronotum, mesonotum, and metanotum are used to distinguish late instar nymphs.

Influence of seasonal variation on the hydro-biogeochemical characteristics of two upland lakes in the Southeastern Amazon, Brazil.

PubMed

Sahoo, Prafulla K; Guimarães, José T F; Souza-Filho, Pedro W M; Silva, Marcio S DA; Silva, Renato O; Pessim, Gustavo; Moraes, Bergson C DE; Pessoa, Paulo F P; Rodrigues, Tarcísio M; Costa, Marlene F DA; Dall'agnol, Roberto

2016-01-01

Limnological characteristics of the Violão and Amendoim lakes, in the Serra dos Carajás, Amazon, were studied interannually (2013-2014). Climate data indicate anomalous conditions during the 2013 rainy period with higher rainfall and lower temperature in the beginning (November). Lake levels were influenced after the first and second hour of each rainfall, which showed a strong synchronization between seasonal fluctuation of lake levels and local weather patterns. Based on the water quality, both lakes are classified as classes "1" and "2" in the CONAMA (Conselho Nacional do Meio Ambiente) scheme and as "excellent" to "good" in the WQI (Water Quality Index) categories. However, the limnology is distinctly different between the lakes and seasons. Higher trophic state and phytoplankton productivity were observed mainly during the rainy period in Violão Lake compared to Amendoim Lake. This may be due to deposition of leached nutrients in the former, mainly total phosphorus (TP), which was probably derived from mafic soils and guano. This is consistent with the significant positive correlation between Chlorophyll-a and TP at the end of the rainy period (March-April), whereas this was not observed in the beginning (November). This could possibly be a consequence of the more intense cloud cover, and unusual high rainfall that limits nutrient availability.

Inferring Large-Scale Terrestrial Water Storage Through GRACE and GPS Data Fusion in Cloud Computing Environments

NASA Astrophysics Data System (ADS)

Rude, C. M.; Li, J. D.; Gowanlock, M.; Herring, T.; Pankratius, V.

2016-12-01

Surface subsidence due to depletion of groundwater can lead to permanent compaction of aquifers and damaged infrastructure. However, studies of such effects on a large scale are challenging and compute intensive because they involve fusing a variety of data sets beyond direct measurements from groundwater wells, such as gravity change measurements from the Gravity Recovery and Climate Experiment (GRACE) or surface displacements measured by GPS receivers. Our work therefore leverages Amazon cloud computing to enable these types of analyses spanning the entire continental US. Changes in groundwater storage are inferred from surface displacements measured by GPS receivers stationed throughout the country. Receivers located on bedrock are anti-correlated with changes in water levels from elastic deformation due to loading, while stations on aquifers correlate with groundwater changes due to poroelastic expansion and compaction. Correlating linearly detrended equivalent water thickness measurements from GRACE with linearly detrended and Kalman filtered vertical displacements of GPS stations located throughout the United States helps compensate for the spatial and temporal limitations of GRACE. Our results show that the majority of GPS stations are negatively correlated with GRACE in a statistically relevant way, as most GPS stations are located on bedrock in order to provide stable reference locations and measure geophysical processes such as tectonic deformations. Additionally, stations located on the Central Valley California aquifer show statistically significant positive correlations. Through the identification of positive and negative correlations, deformation phenomena can be classified as loading or poroelastic expansion due to changes in groundwater. This method facilitates further studies of terrestrial water storage on a global scale. This work is supported by NASA AIST-NNX15AG84G (PI: V. Pankratius) and Amazon.

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

NASA Astrophysics Data System (ADS)

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

2016-02-01

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

Antiplasmodial and Cytotoxic Activity of Raw Plant Extracts as Reported by Knowledgeable Indigenous People of the Amazon Region (Vaupés Medio in Colombia).

PubMed

Pabón, Adriana; Ramirez, Otoniel; Ríos, Alexandra; López, Ena; de Las Salas, Briegel; Cardona, Felipe; Blair, Silvia

2016-05-01

The in vitro antiplasmodial activity of 122 raw extracts prepared in ethanol and water from 35 medicinal plants reported by the Cubeo indigenous village of the Amazon region (Vaupés Medio in Colombia) was evaluated for efficacy against 3D7 (sensitive to chloroquine) and FCR-3 (resistant to chloroquine) Plasmodium falciparum strains. Five percent of these extracts presented a significant antiplasmodial activity (< 5 µg/mL) and 83 % of them were not cytotoxic. These findings highlight the importance of investigating traditional medicinal plants implemented by these ancestral communities of the Amazon region as well as their potential to become a source of new drugs against malaria. Georg Thieme Verlag KG Stuttgart · New York.

Short-term effects of reduced-impact logging on Copaifera spp. (Fabaceae) regeneration in eastern Amazon

Treesearch

Carine Klauberg; Edson Vidal; Carlos Alberto Silva; Andrew Thomas Hudak; Manuela Oliveira; Pedro Higuchi

2017-01-01

Timber management directly influences the population dynamics of tree species, like Copaifera spp. (copaíba), which provide oil-resin with ecological and economic importance. The aim of this study was to evaluate the structure and population dynamics of Copaifera in unmanaged and managed stands by reduced-impact logging (RIL) in eastern Amazon in Pará state, Brazil....

Seasonal and inter-annual dynamics of suspended sediment at the mouth of the Amazon river: The role of continental and oceanic forcing, and implications for coastal geomorphology and mud bank formation

NASA Astrophysics Data System (ADS)

Gensac, Erwan; Martinez, Jean-Michel; Vantrepotte, Vincent; Anthony, Edward J.

2016-04-01

Fine-grained sediments supplied to the Ocean by the Amazon River and their transport under the influence of continental and oceanic forcing drives the geomorphic change along the 1500 km-long coast northward to the Orinoco River delta. The aim of this study is to give an encompassing view of the sediment dynamics in the shallow coastal waters from the Amazon River mouth to the Capes region (northern part of the Amapa region of Brazil and eastern part of French Guiana), where large mud banks are formed. Mud banks are the overarching features in the dynamics of the Amazon-Orinoco coast. They start migrating northward in the Capes region. Suspended Particulate Matter (SPM) concentrations were calculated from satellite products (MODIS Aqua and Terra) acquired over the period 2000-2013. The Census-X11 decomposition method used to discriminate short-term, seasonal and long-term time components of the SPM variability has rendered possible a robust analysis of the impact of continental and oceanic forcing. Continental forcing agents considered are the Amazon River water discharge, SPM concentration and sediment discharge. Oceanic forcing comprises modelled data of wind speed and direction, wave height and direction, and currents. A 150 km-long area of accretion is detected at Cabo Norte that may be linked with a reported increase in the river's sediment discharge concurrent with the satellite data study period. We also assess the rate of mud bank migration north of Cabo Norte, and highlight its variability. Although we confirm a 2 km y-1 migration rate, in agreement with other authors, we show that this velocity may be up to 5 km y-1 along the Cabo Orange region, and we highlight the effect of water discharge by major rivers debouching on this coastal mud belt in modulating such rates. Finally, we propose a refined sediment transport pattern map of the region based on our results and of previous studies in the area such as the AMASSEDS programme, and discuss the relationship between sediment transport and accumulation patterns and the coastal geomorphology of this region.

Influence of landscape heterogeneity on water available to tropical forests in an Amazonian catchment and implications for modeling drought response

NASA Astrophysics Data System (ADS)

Fang, Yilin; Leung, L. Ruby; Duan, Zhuoran; Wigmosta, Mark S.; Maxwell, Reed M.; Chambers, Jeffrey Q.; Tomasella, Javier

2017-08-01

The Amazon basin has experienced periodic droughts in the past, and intense and frequent droughts are predicted in the future. Landscape heterogeneity could play an important role in how tropical forests respond to drought by influencing water available to plants. Using the one-dimensional ACME Land Model and the three-dimensional ParFlow variably saturated flow model, numerical experiments were performed for a catchment in central Amazon to elucidate processes that influence water available for plant use and provide insights for improving Earth system models. Results from ParFlow show that topography has a dominant influence on groundwater table and runoff through lateral flow. Without any representations of lateral processes, ALM simulates very different seasonal variations in groundwater table and runoff compared to ParFlow even if it is able to reproduce the long-term spatial average groundwater table of ParFlow through simple parameter calibration. In the ParFlow simulations, even in the plateau with much deeper water table depth during the dry season in the drought year of 2005, plant transpiration is not water stressed as the soil saturation is still sufficient for the stomata to be fully open based on the empirical wilting formulation in the models. This finding is insensitive to uncertainty in atmospheric forcing and soil parameters, but the empirical wilting formulation is an important factor that should be addressed using observations and modeling of coupled plant hydraulics-soil hydrology processes in future studies. The results could be applicable to other catchments in the Amazon basin with similar seasonal variability and hydrologic regimes.

Chemodiversity of dissolved organic matter in the Amazon Basin

NASA Astrophysics Data System (ADS)

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

2016-07-01

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

A vicious circle of fire, deforestation and climate change: an integrative study for the Amazon region

NASA Astrophysics Data System (ADS)

Thonicke, K.; Rammig, A.; Gumpenberger, M.; Vohland, K.; Poulter, B.; Cramer, W.

2009-04-01

The Amazon rainforest is threatened by deforestation due to wood extraction and agricultural production leading to increasing forest fragmentation and forest degradation. These changes in land surface characteristics and water fluxes are expected to further reduce convective precipitation. Under future climate change the stability of the Amazon rainforest is likely to decrease thus leading to forest dieback (savannization) or forest degradation (secondarization). This puts the Amazon rainforest at risk to reduce the generation of precipitation, to act as a carbon sink and biodiversity hotspot. Fires increased in the past during drought years and in open vegetation thereby further accelerating forest degradation. Deforestation as a result of socioeconomic development in the Amazon basin is projected to further increase in the 21st century and brings climate-induced changes forward. Combined effects of deforestation vs. climate change on the stability of the Amazon rainforest and the role of fire in this system need to be quantified in an integrated study. We present simulation results from future climate (AR4) and deforestation (SimAmazon) experiments using the LPJmL-SPITFIRE vegetation model. Land use change is the main driving factor of forest degradation before 2050, whereas extreme climate change scenarios lead to forest degradation by the end of 2100. Forest fires increase with increasing drought conditions during the 21st century. The resulting effects on vegetation secondarization and savannization and their feedbacks on fire spread and emissions will be presented. The effect of wildfires and intentional burning on forest degradation under future climate and socioeconomic change will be discussed, and recommendations for an integrated land use and fire management are given.

Deep mycoses in Amazon region.

PubMed

Talhari, S; Cunha, M G; Schettini, A P; Talhari, A C

1988-09-01

Patients with deep mycoses diagnosed in dermatologic clinics of Manaus (state of Amazonas, Brazil) were studied from November 1973 to December 1983. They came from the Brazilian states of Amazonas, Pará, Acre, and Rondônia and the Federal Territory of Roraima. All of these regions, with the exception of Pará, are situated in the western part of the Amazon Basin. The climatic conditions in this region are almost the same: tropical forest, high rainfall, and mean annual temperature of 26C. The deep mycoses diagnosed, in order of frequency, were Jorge Lobo's disease, paracoccidioidomycosis, chromomycosis, sporotrichosis, mycetoma, cryptococcosis, zygomycosis, and histoplasmosis.

Renal, gastrointestinal, and hemostatic effects of oral administration of meloxicam to Hispaniolan Amazon parrots (Amazona ventralis).

PubMed

Dijkstra, Bas; Guzman, David Sanchez-Migallon; Gustavsen, Kate; Owens, Sean D; Hass, Carlyle; Kass, Philip H; Paul-Murphy, Joanne R

2015-04-01

To investigate renal, gastrointestinal, and hemostatic effects associated with oral administration of multiple doses of meloxicam to healthy Hispaniolan Amazon parrots (Amazona ventralis). 12 Hispaniolan Amazon parrots. Birds were assigned to receive meloxicam oral suspension (1.6 mg/kg, PO, q 12 h) and 2.5 mL of tap water inserted into the crop by use of a gavage tube (n = 8) or the equivalent volume of tap water only (control group; 4) for 15 days. Urine and feces were collected 2 hours after treatment administration each day. Feces were evaluated for occult blood. Results of a CBC and serum biochemical analysis and measured N-acetyl-β-d-glucosaminidase (NAG) activity and whole blood clotting time were evaluated before, during, and after completion of treatments. Results of urinalysis and measured urine NAG activity were also evaluated. Birds treated with meloxicam had a significant increase in number of WBCs and decrease in PCV from before to after treatment. The PCV also decreased significantly, compared with results for the control group; however, WBC count and PCV for all birds remained within reference ranges throughout the study. One parrot treated with meloxicam had a single high value for urine NAG activity. Meloxicam administered orally at the dosage used in this study caused no apparent negative changes in several renal, gastrointestinal, or hemostatic variables in healthy Hispaniolan Amazon parrots. Additional studies to evaluate adverse effects of NSAIDs in birds will be needed.

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

PubMed

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

2008-08-13

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

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

PubMed Central

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

2008-01-01

Background The western Amazon is the most biologically rich part of the Amazon basin and is home to a great diversity of indigenous ethnic groups, including some of the world's last uncontacted peoples living in voluntary isolation. Unlike the eastern Brazilian Amazon, it is still a largely intact ecosystem. Underlying this landscape are large reserves of oil and gas, many yet untapped. The growing global demand is leading to unprecedented exploration and development in the region. Methodology/Principal Findings We synthesized information from government sources to quantify the status of oil development in the western Amazon. National governments delimit specific geographic areas or “blocks” that are zoned for hydrocarbon activities, which they may lease to state and multinational energy companies for exploration and production. About 180 oil and gas blocks now cover ∼688,000 km2 of the western Amazon. These blocks overlap the most species-rich part of the Amazon. We also found that many of the blocks overlap indigenous territories, both titled lands and areas utilized by peoples in voluntary isolation. In Ecuador and Peru, oil and gas blocks now cover more than two-thirds of the Amazon. In Bolivia and western Brazil, major exploration activities are set to increase rapidly. Conclusions/Significance Without improved policies, the increasing scope and magnitude of planned extraction means that environmental and social impacts are likely to intensify. We review the most pressing oil- and gas-related conservation policy issues confronting the region. These include the need for regional Strategic Environmental Impact Assessments and the adoption of roadless extraction techniques. We also consider the conflicts where the blocks overlap indigenous peoples' territories. PMID:18716679

Crew Earth Observations (CEO) taken during Expedition 9 over Brazil

NASA Image and Video Library

2004-07-20

ISS009-E-15488 (7 July 2004) --- Solimoes-Negro River confluence at Manaus, Amazonia is featured in this image photographed by an Expedition 9 crewmember on the International Space Station (ISS). The largest river on the planet, the Amazon, forms from the confluence of the Solimoes (the upper Amazon River) and the Negro at the Brazilian city of Manaus in central Amazonas. At the river conjunction, the muddy, tan colored waters of the Solimoes meet the “black” water of the Negro River. The unique mixing zone where the waters meet extends downstream through the rainforest for hundreds of kilometers, and is a famous attraction for tourists all over the world. It is the vast quantity of sediment eroded from the Andes Mountains that gives the Solimoes its tan color. By comparison, water in the Negro derives from the low jungles where reduced physical erosion of rock precludes mud entering the river. In place of sediment, organic matter from the forest floor stains the river the color of black tea.

Historic carbon burial spike in an Amazon floodplain lake linked to riparian deforestation near Santarém, Brazil

NASA Astrophysics Data System (ADS)

Sanders, Luciana M.; Taffs, Kathryn; Stokes, Debra; Sanders, Christian J.; Enrich-Prast, Alex; Amora-Nogueira, Leonardo; Marotta, Humberto

2018-01-01

Forests along the Amazon Basin produce significant quantities of organic material, a portion of which is deposited in floodplain lakes. Deforestation in the watershed may then have potentially important effects on the carbon fluxes. In this study, a sediment core was extracted from an Amazon floodplain lake to examine the relationship between carbon burial and changing land cover and land use. Historical records from the 1930s and satellite data from the 1970s were used to calculate deforestation rates between 1930 to 1970 and 1970 to 2010 in four zones with different distances from the margins of the lake and its tributaries (100, 500, 1000 and 6000 m buffers). A sediment accumulation rate of ˜ 4 mm yr-1 for the previous ˜ 120 years was determined from the 240+239Pu signatures and the excess 210Pb method. The carbon burial rates ranged between 85 and 298 g C m-2 yr-1, with pulses of high carbon burial in the 1950s, originating from the forest vegetation as indicated by δ13C and δ15N signatures. Our results revealed a potentially important spatial dependence of the organic carbon (OC) burial in Amazon lacustrine sediments in relation to deforestation rates in the catchment. These deforestation rates were more intense in the riparian vegetation (100 m buffer) during the period 1930 to 1970 and the larger open water areas (500, 1000 and 6000 m buffer) during 1970 to 2010. The continued removal of vegetation from the interior of the forest was not related to the peak of OC burial in the lake, but only the riparian deforestation which peaked during the 1950s. Therefore, this supports the conservation priority of riparian forests as an important management practice for Amazon flooded areas. Our findings suggest the importance of abrupt and temporary events in which some of the biomass released by deforestation, especially restricted to areas along open water edges, might reach the depositional environments in the floodplain of the Amazon Basin.

The Amazon hydrometeorology: Climatology, variability and links to changes in weather patterns

NASA Astrophysics Data System (ADS)

Fernandes, Katia De Avila

My thesis focuses on improving the quantification of the hydrological cycle and understanding the atmospheric processes that link weather to climate in the Amazon River basin. By using ERA40 and independent observations, I assess how well we can estimate the surface water budget in the Amazon River basin. I find that ERA40 basin wide annual precipitation (P) overall agrees with observations showing a slight underestimation of 10% in average, whereas runoff (R) is underestimated by a larger margin (˜25%). Observed residual of precipitation and runoff (denoted as P-R) is better estimated by ERA40 P-R than actual ET which includes soil moisture nudging. The causes for said discrepancies were found to partly relate to soil moisture nudging that needs to be applied during the dry season to produce realistic ET and compensate for the low soil moisture recharge during the previous wet season. Insufficient recharge may in part be caused by underestimation of rainfall amount and intensity; moreover the shallow root layer in the model does not represent the deep soil water reservoir characteristic of the Amazonian forest. Whether the hydrological cycle and weather patterns in the Amazon have changed during the past few decades is a highly debatable but central question for detecting climate change in the region. The second part of my thesis focus on the physical links between rainfall changes detected in observations, and changes of synoptic scale systems as represented by ERA40. My results suggest that an observed delayed wet season onset is consistent with a decreasing number of cold air incursion (CAI) days in southern Amazon for the period 1979--2001. The variability of CAI into southern Amazon is related to the variability of SST upstream of South America in the tropical Pacific and Indian Oceans. A Singular Value Decomposition Analysis (SVD) between CAI days and global SST reveal three main modes of co-variability. The first mode describes the effect of the El Nino-Southern Oscillation. During El Nino (La Nina) a strong (weak) subtropical jet stream over South America tends to prevent transient systems from moving to southern Amazon, resulting in decreased (increased) CAI days during SON. The second mode of co-variability shows an anomalously warm western Indian Ocean also related to strong subtropical jet stream, except the jet is positioned farther north in South America, which along with the absence of a well defined subpolar jet stream, favors the northward displacement of transient waves into central South America, but show little response in southern Amazon. The CAI days reconstructed from the first and second modes do not present any significant trend in southern Amazon. CAI days reconstructed from the third mode of co-variability on the other hand, reproduces the SON observed trend in almost its entirety. The third mode of co-variability describes negative (positive) anomalies in CAI days associated with cold (warm) SST anomalies in the eastern tropical Pacific, anomalous wavetrain in the Southern Hemisphere and Walker Cell displacement that are unfavorable (favorable) to the incursion of CAI into southern Amazon. The temporal evolution of this mode correlates negatively with the Pacific Decadal Oscillation, suggesting that the recent gradual shift in PDO polarity reflected on the interannual response of Southern Pacific atmospheric patterns, hence on the behavior of transients propagation. The negative PDO index and its related atmospheric patterns are in agreement with the reduced observed CAI days, which also related to a delayed wet season onset in the southern Amazon.

Multi-scale Visualization of Remote Sensing and Topographic Data of the Amazon Rain Forest for Environmental Monitoring of the Petroleum Industry.

NASA Astrophysics Data System (ADS)

Fonseca, L.; Miranda, F. P.; Beisl, C. H.; Souza-Fonseca, J.

2002-12-01

PETROBRAS (the Brazilian national oil company) built a pipeline to transport crude oil from the Urucu River region to a terminal in the vicinities of Coari, a city located in the right margin of the Solimoes River. The oil is then shipped by tankers to another terminal in Manaus, capital city of the Amazonas state. At the city of Coari, changes in water level between dry and wet seasons reach up to 14 meters. This strong seasonal character of the Amazonian climate gives rise to four distinct scenarios in the annual hydrological cycle: low water, high water, receding water, and rising water. These scenarios constitute the main reference for the definition of oil spill response planning in the region, since flooded forests and flooded vegetation are the most sensitive fluvial environments to oil spills. This study focuses on improving information about oil spill environmental sensitivity in Western Amazon by using 3D visualization techniques to help the analysis and interpretation of remote sensing and digital topographic data, as follows: (a) 1995 low flood and 1996 high flood JERS-1 SAR mosaics, band LHH, 100m pixel; (b) 2000 low flood and 2001 high flood RADARSAT-1 W1 images, band CHH, 30m pixel; (c) 2002 high flood airborne SAR images from the SIVAM project (System for Surveillance of the Amazon), band LHH, 3m pixel and band XHH, 6m pixel; (d) GTOPO30 digital elevation model, 30' resolution; (e) Digital elevation model derived from topographic information acquired during seismic surveys, 25m resolution; (f) panoramic views obtained from low altitude helicopter flights. The methodology applied includes image processing, cartographic conversion and generation of value-added product using 3D visualization. A semivariogram textural classification was applied to the SAR images in order to identify areas of flooded forest and flooded vegetation. The digital elevation models were color shaded to highlight subtle topographic features. Both datasets were then converted to the same cartographic projection and inserted into the Fledermaus 3D visualization environment. 3D visualization proved to be an important aid in understanding the spatial distribution pattern of the environmentally sensitive vegetation cover. The dynamics of the hydrological cycle was depicted in a basin-wide scale, revealing new geomorphic information relevant to assess the environmental risk of oil spills. Results demonstrate that pipelines constitute an environmentally saver option for oil transportation in the region when compared to fluvial tanker routes.

Brazil and the United States: Security Issues for the Twenty-First Century

DTIC Science & Technology

2001-01-01

American continent. Its Atlantic Ocean coastline stretches for 4,600 miles. The country contains the bulk of the Amazon Basin with the largest...Paraguay, Bolivia, Peru , Columbia, Venezuela, Guyana, Suriname and French Guiana.[2] With the exception of Columbia, Brazil has cordial diplomatic...relations with its contiguous neighbors. Brazil’s Amazon jungle border with Columbia poses serious challenges from Columbia’s narcotics trade. Brazil

Spatial and temporal variations of evapotranspiration, groundwater and precipitation in Amazonia

NASA Astrophysics Data System (ADS)

Niu, J.; Riley, W. J.; Shen, C.; Melack, J. M.; Qiu, H.

2017-12-01

We used wavelet coherence analysis to investigate the effects of precipitation (P) and groundwater dynamics (total water storage anomaly, TWSA) on evapotranspiration (ET) at kilometer, sub-basin, and whole basin scales in the Amazon basin. The Amazon-scale averaged ET, P, and TWSA have about the same annual periodicity. The phase lag between ET and P (ΦET-P) is 1 to 3 months, and between ET and TWSA (ΦET-TWSA) is 3 to 7 months. The phase patterns have a south-north divide due to significant variation in climatic conditions. The correlation between ΦET-P and ΦET-TWSA is affected by the aridity index (the ratio between potential ET (PET) and P, PET / P), of each sub-basin, as determined using the Budyko framework at the sub-basin level. The spatial structure of ΦET-P is negatively correlated with the spatial structure of annual ET. At Amazon-scale during a drought year (e.g., 2010), both phases decreased, while in the subsequent years, ΦET-TWSA increased, indicating strong groundwater effects on ET immediately following dry years Amazon-wide.

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

NASA Astrophysics Data System (ADS)

Poveda, G.; Zapata, A. F.

2016-12-01

The Andes-Amazon system exhibits complex interactions and feedbacks between hydrological, ecological, biogeochemical and climatic factors in a broad range of temporal and spatial scales. We aim to understand the coupling existing between water, energy and carbon budgets in the Andes-Amazon system, by performing a systematic study of the system for river basins of increasing Horton-Strahler orders, from the headwaters of the Amazon River basin along the Andes (order ω=1 river sub-basins) to the low-lying larger river sub-basins (order ω=10). To that end, this works introduces a 3-D generalization of the Budyko framework that aims to link the water, energy, and Carbon budgets in river basins. The newly proposed 3-D non-dimensional space is defined by: (1) the ratio between long-term mean values of Actual Evapotranspiration (AET) and Precipitation (P), α=AET/P, representing the water balance; (2) the ratio between AET and Potential Evapotranspiration (PET), β=AET/PET, representing the energy balance; and (3) the ratio between AET and Aboveground Net Primary Productivity, δ=AET/ANPP, representing the carbon budget. We use a 3" Digital Elevation Model (DEM), which allows defining river basins with Horton-Strahler orders from 1 to 10. The long-term water, energy, and carbon budgets are estimated for increasing values of the Horton-Strahler orders during the period 1987-2007. Data sets pertaining to the water balance come from ORE-HYBAM, potential evapotranspiration (PET) from GLEAM (Global Land-surface Evaporation: the Amsterdam Methodology). Data for the energy budget are from the Surface Radiation Budget (SRB). Data for the Carbon budget (annual mean net primary productivity, ANPP, gross primary productivity, GPP, and respiration rates, Rr, come from AMAZALERT and ORCHEDEE (Organizing Carbon and Hydrology In Dynamic EcosystEms), as well as from Flux Tower Data and the LBA project. Our results show that scale invariant power-laws emerge to capture the three 2-D cross-sections of the newly proposed 3-D non-dimensional space. The scaling exponents of the identified power laws remain invariant for river basins of Horton-Strahler orders from ω=2 to ω=8. We advance to explain the scaling exponents of the identified power laws in terms of the main physical processes.

Predicting the response of the Amazon rainforest to persistent drought conditions under current and future climates: a major challenge for global land surface models

NASA Astrophysics Data System (ADS)

Joetzjer, E.; Delire, C.; Douville, H.; Ciais, P.; Decharme, B.; Fisher, R.; Christoffersen, B.; Calvet, J. C.; da Costa, A. C. L.; Ferreira, L. V.; Meir, P.

2014-12-01

While a majority of global climate models project drier and longer dry seasons over the Amazon under higher CO2 levels, large uncertainties surround the response of vegetation to persistent droughts in both present-day and future climates. We propose a detailed evaluation of the ability of the ISBACC (Interaction Soil-Biosphere-Atmosphere Carbon Cycle) land surface model to capture drought effects on both water and carbon budgets, comparing fluxes and stocks at two recent throughfall exclusion (TFE) experiments performed in the Amazon. We also explore the model sensitivity to different water stress functions (WSFs) and to an idealized increase in CO2 concentration and/or temperature. In spite of a reasonable soil moisture simulation, ISBACC struggles to correctly simulate the vegetation response to TFE whose amplitude and timing is highly sensitive to the WSF. Under higher CO2 concentrations, the increased water-use efficiency (WUE) mitigates the sensitivity of ISBACC to drought. While one of the proposed WSF formulations improves the response of most ISBACC fluxes, except respiration, a parameterization of drought-induced tree mortality is missing for an accurate estimate of the vegetation response. Also, a better mechanistic understanding of the forest responses to drought under a warmer climate and higher CO2 concentration is clearly needed.

Amazon rainforest modulation of water security in the Pantanal wetland.

PubMed

Bergier, Ivan; Assine, Mario L; McGlue, Michael M; Alho, Cleber J R; Silva, Aguinaldo; Guerreiro, Renato L; Carvalho, João C

2018-04-01

The Pantanal is a large wetland mainly located in Brazil, whose natural resources are important for local, regional and global economies. Many human activities in the region rely on Pantanal's ecosystem services including cattle breeding for beef production, professional and touristic fishing, and contemplative tourism. The conservation of natural resources and ecosystems services provided by the Pantanal wetland must consider strategies for water security. We explored precipitation data from 1926 to 2016 provided by a regional network of rain gauge stations managed by the Brazilian Government. A timeseries obtained by dividing the monthly accumulated-rainfall by the number of rainy days indicated a positive trend of the mean rate of rainy days (mm/day) for the studied period in all seasons. We assessed the linkage of Pantanal's rainfall patterns with large-scale climate data in South America provided by NOAA/ESRL from 1949 to 2016. Analysis of spatiotemporal correlation maps indicated that, in agreement with previous studies, the Amazon biome plays a significant role in controlling summer rainfall in the Pantanal. Based on these spatiotemporal maps, a multi-linear regression model was built to predict the mean rate of summer rainy days in Pantanal by 2100, relative to the 1961-1990 mean reference. We found that the deforestation of the Amazon rainforest has profound implications for water security and the conservation of Pantanal's ecosystem services. Copyright © 2017 Elsevier B.V. All rights reserved.

The importance of forest structure for carbon fluxes of the Amazon rainforest

NASA Astrophysics Data System (ADS)

Rödig, Edna; Cuntz, Matthias; Rammig, Anja; Fischer, Rico; Taubert, Franziska; Huth, Andreas

2018-05-01

Precise descriptions of forest productivity, biomass, and structure are essential for understanding ecosystem responses to climatic and anthropogenic changes. However, relations between these components are complex, in particular for tropical forests. We developed an approach to simulate carbon dynamics in the Amazon rainforest including around 410 billion individual trees within 7.8 million km2. We integrated canopy height observations from space-borne LIDAR in order to quantify spatial variations in forest state and structure reflecting small-scale to large-scale natural and anthropogenic disturbances. Under current conditions, we identified the Amazon rainforest as a carbon sink, gaining 0.56 GtC per year. This carbon sink is driven by an estimated mean gross primary productivity (GPP) of 25.1 tC ha‑1 a‑1, and a mean woody aboveground net primary productivity (wANPP) of 4.2 tC ha‑1 a‑1. We found that successional states play an important role for the relations between productivity and biomass. Forests in early to intermediate successional states are the most productive, and woody above-ground carbon use efficiencies are non-linear. Simulated values can be compared to observed carbon fluxes at various spatial resolutions (>40 m). Notably, we found that our GPP corresponds to the values derived from MODIS. For NPP, spatial differences can be observed due to the consideration of forest successional states in our approach. We conclude that forest structure has a substantial impact on productivity and biomass. It is an essential factor that should be taken into account when estimating current carbon budgets or analyzing climate change scenarios for the Amazon rainforest.

Brazilian mosquito (Diptera: Culicidae) fauna: I. Anopheles species from Porto Velho, Rondônia state, western Amazon, Brazil.

PubMed

Morais, Sirlei Antunes; Urbinatti, Paulo Roberto; Sallum, Maria Anice Mureb; Kuniy, Adriana Akemi; Moresco, Gilberto Gilmar; Fernandes, Aristides; Nagaki, Sandra Sayuri; Natal, Delsio

2012-12-01

This study contributes to knowledge of Anopheles species, including vectors of Plasmodium from the western Brazilian Amazon in Porto Velho, Rondônia State. The sampling area has undergone substantial environmental changes as a consequence of agricultural and hydroelectric projects, which have caused intensive deforestation and favored habitats for some mosquito species. The purpose of this study was to diagnose the occurrence of anopheline species from collections in three locations along an electric-power transmission line. Each locality was sampled three times from 2010 to 2011. The principal adult mosquitoes captured in Shannon trap were Anopheles darlingi, An. triannulatus, An. nuneztovari l.s., An.gilesi and An. costai. In addition, larvae were collected in ground breeding sites for Anopheles braziliensis, An. triannulatus, An. darlingi, An. deaneorum, An. marajoara, An. peryassui, An. nuneztovari l.s. and An. oswaldoi-konderi. Anopheles darlingi was the most common mosquito in the region. We discuss Culicidae systematics, fauna distribution, and aspects of malaria in altered habitats of the western Amazon.

Deforestation control in Mato Grosso: a new model for slowing the loss of Brazil's Amazon forest.

PubMed

Fearnside, Philip M

2003-08-01

Controlling deforestation in Brazil's Amazon region has long been illusive despite repeated efforts of government authorities to slow the process. From 1997 to 2000, deforestation rates in Brazil's 9-state "Legal Amazon" region continually crept upward. Now, a licensing and enforcement program for clearing by large farmers and ranchers in the state of Mato Grosso appears to be having an effect. The deforestation rate in Mato Grosso was already beginning to slacken before initiation of the program in 1999, but examination of county-level data suggests that deforestation in already heavily cleared areas was falling due to lack of suitable uncleared land, while little-cleared areas were experiencing rapid deforestation. Following initiation of the program, the clearing rates declined in the recent frontiers. Areas with greater enforcement effort also appear to have experienced greater declines. Demonstration of government ability to enforce regulations and influence trends is important to domestic and international debates regarding use of avoided deforestation to mitigate global warming.

No Free Lunch - Trading Away Ecosystem Services from Agriculture in the Brazilian Amazon

NASA Astrophysics Data System (ADS)

Zaks, D.; Foley, J.

2008-12-01

In the age of globalization, many crops and animal products are transported across the long distances for consumption elsewhere. The alteration of water, soil and climate systems from agricultural practices can be attributed to both exporting and importing countries. Quantities of water, carbon and nutrients (e.g. nitrogen and phosphorus) can be tracked throughout the production process and be aggregated from field to table. The synthesis of this data can be used to inform markets to appropriately price the most ecologically efficient production.While agricultural land is undergoing changes around the world, the Brazilian Amazon has seen a dramatic conversion of forest and grassland due to the expanding agricultural frontier, and intense growth in the future has been predicted in the region. As a proof of concept, I plan to study the flow of ecosystem services from the Amazon rainforest basin to the world market. Cattle and soybeans are the two main agricultural products of the region and are produced for both internal consumption and for export. This work quantifies agricultural production and its associated ecosystem services using socio-economic and commodity trade data, numerical ecosystem models and remote sensing products.

Impacts of Groundwater on the Atmospheric Convection in Amazon using Multi-GCM Simulations from I-GEM project

NASA Astrophysics Data System (ADS)

Lo, M. H.; Chien, R. Y.; Ducharne, A.; Decharme, B.; Lan, C. W.; Wang, F.; Cheruy, F.; Colin, J.

2017-12-01

Previous research indicated that groundwater plays an important role in hydrological cycle and is a major source of water vapor in climate models, which may result in modifications of atmospheric convection. For instance, our previous study showed that when considering the groundwater dynamics in a GCM, the wet soil induced surface cooling effect can further reduce the Amazon dry season convection and precipitation. However, the main mechanisms of the interaction among groundwater, soil moisture, and precipitation are still unclear, and they need to be examined in several climate models. In this study, we further examine the influence of the surface cooling effects due to the groundwater on the convection over the Amazon. To this end, we use idealized simulations of the IGEM (Impact of Groundwater in Earth system Models) project, with 3 GCMs (CESM, CNRM, and IPSL): in each of them, we prescribed a water table at a constant depth throughout all land areas, to create globally wet conditions. Preliminary analysis shows a contradict result of the tendency of precipitation in the three models with wet condition which indicates a great uncertainty of the groundwater's impacts in coupled GCMs.

Divergent biophysical controls of aquatic CO2 and CH4 in the World’s two largest rivers

PubMed Central

Borges, Alberto V.; Abril, Gwenaël; Darchambeau, François; Teodoru, Cristian R.; Deborde, Jonathan; Vidal, Luciana O.; Lambert, Thibault; Bouillon, Steven

2015-01-01

Carbon emissions to the atmosphere from inland waters are globally significant and mainly occur at tropical latitudes. However, processes controlling the intensity of CO2 and CH4 emissions from tropical inland waters remain poorly understood. Here, we report a data-set of concurrent measurements of the partial pressure of CO2 (pCO2) and dissolved CH4 concentrations in the Amazon (n = 136) and the Congo (n = 280) Rivers. The pCO2 values in the Amazon mainstem were significantly higher than in the Congo, contrasting with CH4 concentrations that were higher in the Congo than in the Amazon. Large-scale patterns in pCO2 across different lowland tropical basins can be apprehended with a relatively simple statistical model related to the extent of wetlands within the basin, showing that, in addition to non-flooded vegetation, wetlands also contribute to CO2 in river channels. On the other hand, dynamics of dissolved CH4 in river channels are less straightforward to predict, and are related to the way hydrology modulates the connectivity between wetlands and river channels. PMID:26494107

Dispersal and Diving Adjustments of the Green Turtle Chelonia mydas in Response to Dynamic Environmental Conditions during Post-Nesting Migration

PubMed Central

Chambault, Philippine; Pinaud, David; Vantrepotte, Vincent; Kelle, Laurent; Entraygues, Mathieu; Guinet, Christophe; Berzins, Rachel; Bilo, Karin; Gaspar, Philippe; de Thoisy, Benoît; Le Maho, Yvon; Chevallier, Damien

2015-01-01

In response to seasonality and spatial segregation of resources, sea turtles undertake long journeys between their nesting sites and foraging grounds. While satellite tracking has made it possible to outline their migration routes, we still have little knowledge of how they select their foraging grounds and adapt their migration to dynamic environmental conditions. Here, we analyzed the trajectories and diving behavior of 19 adult green turtles (Chelonia mydas) during their post-nesting migration from French Guiana and Suriname to their foraging grounds off the coast of Brazil. First Passage Time analysis was used to identify foraging areas located off Ceará state of Brazil, where the associated habitat corresponds to favorable conditions for seagrass growth, i.e. clear and shallow waters. The dispersal and diving patterns of the turtles revealed several behavioral adaptations to the strong hydrodynamic processes induced by both the North Brazil current and the Amazon River plume. All green turtles migrated south-eastward after the nesting season, confirming that they coped with the strong counter North Brazil current by using a tight corridor close to the shore. The time spent within the Amazon plume also altered the location of their feeding habitats as the longer individuals stayed within the plume, the sooner they initiated foraging. The green turtles performed deeper and shorter dives while crossing the mouth of the Amazon, a strategy which would help turtles avoid the most turbulent upper surface layers of the plume. These adjustments reveal the remarkable plasticity of this green turtle population when reducing energy costs induced by migration. PMID:26398528

Dispersal and Diving Adjustments of the Green Turtle Chelonia mydas in Response to Dynamic Environmental Conditions during Post-Nesting Migration.

PubMed

Chambault, Philippine; Pinaud, David; Vantrepotte, Vincent; Kelle, Laurent; Entraygues, Mathieu; Guinet, Christophe; Berzins, Rachel; Bilo, Karin; Gaspar, Philippe; de Thoisy, Benoît; Le Maho, Yvon; Chevallier, Damien

2015-01-01

In response to seasonality and spatial segregation of resources, sea turtles undertake long journeys between their nesting sites and foraging grounds. While satellite tracking has made it possible to outline their migration routes, we still have little knowledge of how they select their foraging grounds and adapt their migration to dynamic environmental conditions. Here, we analyzed the trajectories and diving behavior of 19 adult green turtles (Chelonia mydas) during their post-nesting migration from French Guiana and Suriname to their foraging grounds off the coast of Brazil. First Passage Time analysis was used to identify foraging areas located off Ceará state of Brazil, where the associated habitat corresponds to favorable conditions for seagrass growth, i.e. clear and shallow waters. The dispersal and diving patterns of the turtles revealed several behavioral adaptations to the strong hydrodynamic processes induced by both the North Brazil current and the Amazon River plume. All green turtles migrated south-eastward after the nesting season, confirming that they coped with the strong counter North Brazil current by using a tight corridor close to the shore. The time spent within the Amazon plume also altered the location of their feeding habitats as the longer individuals stayed within the plume, the sooner they initiated foraging. The green turtles performed deeper and shorter dives while crossing the mouth of the Amazon, a strategy which would help turtles avoid the most turbulent upper surface layers of the plume. These adjustments reveal the remarkable plasticity of this green turtle population when reducing energy costs induced by migration.

Terrestrial Carbon Sinks in the Brazilian Amazon and Cerrado Region Predicted from MODIS Satellite Data and Ecosystem Modeling

NASA Technical Reports Server (NTRS)

Potter, C.; Klooster, S.; Huete, A.; Genovese, V.; Bustamante, M.; Ferreira, L. Guimaraes; deOliveira, R. C., Jr.; Zepp, R.

2009-01-01

A simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate monthly carbon fluxes in terrestrial ecosystems of Brazilian Amazon and Cerrado regions over the period 2000-2004. Net ecosystem production (NEP) flux for atmospheric CO2 in the region for these years was estimated. Consistently high carbon sink fluxes in terrestrial ecosystems on a yearly basis were found in the western portions of the states of Acre and Rondonia and the northern portions of the state of Par a. These areas were not significantly impacted by the 2002-2003 El Nino event in terms of net annual carbon gains. Areas of the region that show periodically high carbon source fluxes from terrestrial ecosystems to the atmosphere on yearly basis were found throughout the state of Maranhao and the southern portions of the state of Amazonas. As demonstrated though tower site comparisons, NEP modeled with monthly MODIS Enhanced Vegetation Index (EVI) inputs closely resembles the measured seasonal carbon fluxes at the LBA Tapajos tower site. Modeling results suggest that the capacity for use of MODIS Enhanced Vegetation Index (EVI) data to predict seasonal uptake rates of CO2 in Amazon forests and Cerrado woodlands is strong.

Export of nutrients and major ionic solutes from a rain forest catchment in the Central Amazon Basin

NASA Astrophysics Data System (ADS)

Lesack, Lance F. W.

1993-03-01

The relative roles of base flow runoff versus storm flow runoff versus subsurface outflow in controlling total export of solutes from a 23.4-ha catchment of undisturbed rain forest in the central Amazon Basin were evaluated from water and solute flux measurements performed over a 1 year period. Solutes exported via 173 storms during the study were estimated from stream water samples collected during base flow conditions and during eight storms, and by utilizing a hydrograph separation technique in combination with a mixing model to partition storm flow from base flow fluxes. Solutes exported by subsurface outflow were estimated from groundwater samples from three nests of piezometers installed into the streambed, and concurrent measurements of hydraulic conductivity and hydraulic head gradients. Base flow discharge represented 92% of water outflow from the basin and was the dominant pathway of solute export. Although storm flow discharge represented only 5% of total water outflow, storm flow solute fluxes represented up to 25% of the total annual export flux, though for many solutes the portion was less. Subsurface outflow represented only 2.5% of total water outflow, and subsurface solute fluxes never represented more than 5% of the total annual export flux. Measurement errors were relatively high for storm flow and subsurface outflow fluxes, but cumulative measurement errors associated with the total solute fluxes exported from the catchment, in most cases, ranged from only ±7% to 14% because base flow fluxes were measured relatively well. The export fluxes of most solutes are substantially less than previously reported for comparable small catchments in the Amazon basin, and these differences cannot be reconciled by the fact that storm flow and subsurface outflows were not appropriately measured in previous studies.

Human impacts on soil carbon dynamics of deep-rooted Amazonian forests

NASA Technical Reports Server (NTRS)

Nepstad, Daniel C.; Stone, Thomas A.; Davidson, Eric A.

1994-01-01

Deforestation and logging degrade more forest in eastern and southern Amazonia than in any other region of the world. This forest alteration affects regional hydrology and the global carbon cycle, but our current understanding of these effects is limited by incomplete knowledge of tropical forest ecosystems. It is widely agreed that roots are concentrated near the soil surface in moist tropical forests, but this generalization incorrectly implies that deep roots are unimportant in water and C budgets. Our results indicate that half of the closed-canopy forests of Brazilian Amazonic occur where rainfall is highly seasonal, and these forests rely on deeply penetrating roots to extract soil water. Pasture vegetation extracts less water from deep soil than the forest it replaces, thus increasing rates of drainage and decreasing rates of evapotranspiration. Deep roots are also a source of modern carbon deep in the soil. The soils of the eastern Amazon contain more carbon below 1 m depth than is present in above-ground biomass. As much as 25 percent of this deep soil C could have annual to decadal turnover times and may be lost to the atmosphere following deforestation. We compared the importance of deep roots in a mature, evergreen forest with an adjacent man-made pasture, the most common type of vegetation on deforested land in Amazonia. The study site is near the town of Paragominas, in the Brazilian state of Para, with a seasonal rainfall pattern and deeply-weathered, kaolinitic soils that are typical for large portions of Amazonia. Root distribution, soil water extraction, and soil carbon dynamics were studied using deep auger holes and shafts in each ecosystem, and the phenology and water status of the leaf canopies were measured. We estimated the geographical distribution of deeply-rooting forests using satellite imagery, rainfall data, and field measurements.

Airborne and spaceborne radar images for geologic and environmental mapping in the Amazon rain forest, Brazil

NASA Technical Reports Server (NTRS)

Hurtak, James J.; Ford, John P.

1986-01-01

Spaceborne and airborne radar image of portions of the Middle and Upper Amazon basin in the state of Amazonas and the Territory of Roraima are compared for purposes of geological and environmental mapping. The contrasted illumination geometries and imaging parameters are related to terrain slope and surface roughness characteristics for corresponding areas that were covered by each of the radar imaging systems. Landforms range from deeply dissected mountain and plateau with relief up to 500 m in Roraima, revealing ancient layered rocks through folded residual mountains to deeply beveled pediplain in Amazonas. Geomorphic features provide distinct textural signatures that are characteristic of different rock associations. The principle drainages in the areas covered are the Rio Negro, Rio Branco, and the Rio Japura. Shadowing effects and low radar sensitivity to subtle linear fractures that are aligned parallel or nearly parallel to the direction of radar illumination illustrate the need to obtain multiple coverage with viewing directions about 90 degrees. Perception of standing water and alluvial forest in floodplains varies with incident angle and with season. Multitemporal data sets acquired over periods of years provide an ideal method of monitoring environmental changes.

Spatial patterns of water quality in Xingu River Basin (Amazonia) prior to the Belo Monte dam impoundment.

PubMed

Rodrigues-Filho, J L; Abe, D S; Gatti-Junior, P; Medeiros, G R; Degani, R M; Blanco, F P; Faria, C R L; Campanelli, L; Soares, F S; Sidagis-Galli, C V; Teixeira-Silva, V; Tundisi, J E M; Matsmura-Tundisi, T; Tundisi, J G

2015-08-01

The Xingu River, one of the most important of the Amazon Basin, is characterized by clear and transparent waters that drain a 509.685 km2 watershed with distinct hydrological and ecological conditions and anthropogenic pressures along its course. As in other basins of the Amazon system, studies in the Xingu are scarce. Furthermore, the eminent construction of the Belo Monte for hydropower production, which will alter the environmental conditions in the basin in its lower middle portion, denotes high importance of studies that generate relevant information that may subsidize a more balanced and equitable development in the Amazon region. Thus, the aim of this study was to analyze the water quality in the Xingu River and its tributaries focusing on spatial patterns by the use of multivariate statistical techniques, identifying which water quality parameters were more important for the environmental changes in the watershed. Data sampling were carried out during two complete hydrological cycles in twenty-five sampling stations. The data of twenty seven variables were analyzed by Spearman's correlation coefficients, cluster analysis (CA), and principal component analysis (PCA). The results showed a high auto-correlation between variables (> 0.7). These variables were removed from multivariate analyzes because they provided redundant information about the environment. The CA resulted in the formation of six clusters, which were clearly observed in the PCA and were characterized by different water quality. The statistical results allowed to identify a high spatial variation in the water quality, which were related to specific features of the environment, different uses, influences of anthropogenic activities and geochemical characteristics of the drained basins. It was also demonstrated that most of the sampling stations in the Xingu River basin showed good water quality, due to the absence of local impacts and high power of depuration of the river itself.

Selective logging in the Brazilian Amazon.

PubMed

Asner, Gregory P; Knapp, David E; Broadbent, Eben N; Oliveira, Paulo J C; Keller, Michael; Silva, Jose N

2005-10-21

Amazon deforestation has been measured by remote sensing for three decades. In comparison, selective logging has been mostly invisible to satellites. We developed a large-scale, high-resolution, automated remote-sensing analysis of selective logging in the top five timber-producing states of the Brazilian Amazon. Logged areas ranged from 12,075 to 19,823 square kilometers per year (+/-14%) between 1999 and 2002, equivalent to 60 to 123% of previously reported deforestation area. Up to 1200 square kilometers per year of logging were observed on conservation lands. Each year, 27 million to 50 million cubic meters of wood were extracted, and a gross flux of approximately 0.1 billion metric tons of carbon was destined for release to the atmosphere by logging.

Properties and reactivity of aquatic organic matter from an Amazonian floodplain system

NASA Astrophysics Data System (ADS)

Perez, M. A. P.; Benedetti, M. F.; Moreira-Turcq, P.

2009-04-01

The aim of this study was to characterize the nature of the bulk dissolved organic matter (DOM) in different types of environments in the Amazon River-floodplain system and determine the importance of two different fractions of dissolved organic matter onto adsorption processes that occurs through the transport of organic matter in the Amazon Basin. Seven samples were collected in the Amazon River - "Lago Grande de Curuai" floodplain system, in rising water levels cruise (March 2006). The samples were taken in the Amazon main stem, in white and black floodplain waters, and in the middle of a phytoplaktonic bloom. The bulk, dissolved (i.e. < 0.22 micrometer), hydrophobic (HPO) and transphilic (TPH) fractions extracted by XAD-8 and XAD-4 columns chromatography respectively were isolated. Organic carbon (OC) and total nitrogen (TN) concentrations, Specific UV absorbance (SUVA), Size-Exclusion Chromatography (SEC), d13C and d15N isotopes, and reactivity (acid-base titration) were characterized for these fractions. Adsorption experiments onto mineral phase from de surface sediment of the Curuai floodplain lake (rich in smectite and kaolinite) were realized with HPO and TPH fractions. The OC concentrations in the natural organic matter (Bulk and < 0.22 micrometer fractions) varied between 3.7-5.7 mg/L. The OC and TN concentrations varied between 510 - 528 mg C/g in the HPO fraction, and 408 - 462 mg C/g in the TPH compounds and between 14.3 - 17.6 mg N/g (HPO), and 22.1 - 30.0 mg N/g (TPH). The molecular weight of both fractions (HPO and TPH) didn't present significant variation. Both fractions presented high aromaticity and they were rich in carboxylic groups, although smaller values are systematically reported for the HPO fractions. The OM of the main stem was the most adsorbed, followed by the white water lake, the phytoplanktonic bloom, and black water lake sample. These results helped us to strengthen the hypothesis that the organic matter carried from the river and sediment in the floodplain is closely associated with mineral phase.

Drought sensitivity of the Amazon rainforest.

PubMed

Phillips, Oliver L; Aragão, Luiz E O C; Lewis, Simon L; Fisher, Joshua B; Lloyd, Jon; López-González, Gabriela; Malhi, Yadvinder; Monteagudo, Abel; Peacock, Julie; Quesada, Carlos A; van der Heijden, Geertje; Almeida, Samuel; Amaral, Iêda; Arroyo, Luzmila; Aymard, Gerardo; Baker, Tim R; Bánki, Olaf; Blanc, Lilian; Bonal, Damien; Brando, Paulo; Chave, Jerome; de Oliveira, Atila Cristina Alves; Cardozo, Nallaret Dávila; Czimczik, Claudia I; Feldpausch, Ted R; Freitas, Maria Aparecida; Gloor, Emanuel; Higuchi, Niro; Jiménez, Eliana; Lloyd, Gareth; Meir, Patrick; Mendoza, Casimiro; Morel, Alexandra; Neill, David A; Nepstad, Daniel; Patiño, Sandra; Peñuela, Maria Cristina; Prieto, Adriana; Ramírez, Fredy; Schwarz, Michael; Silva, Javier; Silveira, Marcos; Thomas, Anne Sota; Steege, Hans Ter; Stropp, Juliana; Vásquez, Rodolfo; Zelazowski, Przemyslaw; Alvarez Dávila, Esteban; Andelman, Sandy; Andrade, Ana; Chao, Kuo-Jung; Erwin, Terry; Di Fiore, Anthony; Honorio C, Eurídice; Keeling, Helen; Killeen, Tim J; Laurance, William F; Peña Cruz, Antonio; Pitman, Nigel C A; Núñez Vargas, Percy; Ramírez-Angulo, Hirma; Rudas, Agustín; Salamão, Rafael; Silva, Natalino; Terborgh, John; Torres-Lezama, Armando

2009-03-06

Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 x 10(15) to 1.6 x 10(15) grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change.

Particulate Organic Matter Distribution along the Lower Amazon River: Addressing Aquatic Ecology Concepts Using Fatty Acids

PubMed Central

Mortillaro, Jean-Michel; Rigal, François; Rybarczyk, Hervé; Bernardes, Marcelo; Abril, Gwenaël; Meziane, Tarik

2012-01-01

One of the greatest challenges in understanding the Amazon basin functioning is to ascertain the role played by floodplains in the organic matter (OM) cycle, crucial for a large spectrum of ecological mechanisms. Fatty acids (FAs) were combined with environmental descriptors and analyzed through multivariate and spatial tools (asymmetric eigenvector maps, AEM and principal coordinates of neighbor matrices, PCNM). This challenge allowed investigating the distribution of suspended particulate organic matter (SPOM), in order to trace its seasonal origin and quality, along a 800 km section of the Amazon river-floodplain system. Statistical analysis confirmed that large amounts of saturated FAs (15:0, 18:0, 24:0, 25:0 and 26:0), an indication of refractory OM, were concomitantly recorded with high pCO2 in rivers, during the high water season (HW). Contrastingly, FAs marker which may be attributed in this ecosystem to aquatic plants (18:2ω6 and 18:3ω3) and cyanobacteria (16:1ω7), were correlated with higher O2, chlorophyll a and pheopigments in floodplains, due to a high primary production during low waters (LW). Decreasing concentrations of unsaturated FAs, that characterize labile OM, were recorded during HW, from upstream to downstream. Furthermore, using PCNM and AEM spatial methods, FAs compositions of SPOM displayed an upstream-downstream gradient during HW, which was attributed to OM retention and the extent of flooded forest in floodplains. Discrimination of OM quality between the Amazon River and floodplains corroborate higher autotrophic production in the latter and transfer of OM to rivers at LW season. Together, these gradients demonstrate the validity of FAs as predictors of spatial and temporal changes in OM quality. These spatial and temporal trends are explained by 1) downstream change in landscape morphology as predicted by the River Continuum Concept; 2) enhanced primary production during LW when the water level decreased and its residence time increased as predicted by the Flood Pulse Concept. PMID:23029412

Trypanosoma cruzi IV causing outbreaks of acute Chagas disease and infections by different haplotypes in the Western Brazilian Amazonia.

PubMed

Monteiro, Wuelton Marcelo; Magalhães, Laylah Kelre Costa; de Sá, Amanda Regina Nichi; Gomes, Mônica Lúcia; Toledo, Max Jean de Ornelas; Borges, Lara; Pires, Isa; Guerra, Jorge Augusto de Oliveira; Silveira, Henrique; Barbosa, Maria das Graças Vale

2012-01-01

Chagas disease is an emergent tropical disease in the Brazilian Amazon Region, with an increasing number of cases in recent decades. In this region, the sylvatic cycle of Trypanosoma cruzi transmission, which constitutes a reservoir of parasites that might be associated with specific molecular, epidemiological and clinical traits, has been little explored. The objective of this work is to genetically characterize stocks of T. cruzi from human cases, triatomines and reservoir mammals in the State of Amazonas, in the Western Brazilian Amazon. We analyzed 96 T. cruzi samples from four municipalities in distant locations of the State of Amazonas. Molecular characterization of isolated parasites from cultures in LIT medium or directly from vectors or whole human blood was performed by PCR of the non-transcribed spacer of the mini-exon and of the 24 S alfa ribosomal RNA gene, RFLP and sequencing of the mitochondrial cytochrome c oxidase subunit II (COII) gene, and by sequencing of the glucose-phosphate isomerase gene. The T. cruzi parasites from two outbreaks of acute disease were all typed as TcIV. One of the outbreaks was triggered by several haplotypes of the same DTU. TcIV also occurred in isolated cases and in Rhodnius robustus. Incongruence between mitochondrial and nuclear phylogenies is likely to be indicative of historical genetic exchange events resulting in mitochondrial introgression between TcIII and TcIV DTUs from Western Brazilian Amazon. TcI predominated among triatomines and was the unique DTU infecting marsupials. DTU TcIV, rarely associated with human Chagas disease in other areas of the Amazon basin, is the major strain responsible for the human infections in the Western Brazilian Amazon, occurring in outbreaks as single or mixed infections by different haplotypes.

New records of tick-associated spotted fever group Rickettsia in an Amazon-Savannah ecotone, Brazil.

PubMed

Aguirre, A A R; Garcia, Marcos Valério; Costa, Ivaneide Nunes da; Csordas, Bárbara Guimarães; Rodrigues, Vinícius da Silva; Medeiros, Jansen Fernandes; Andreotti, Renato

2018-05-01

Human rickettsiosis has been recorded in the Amazon Biome. However, the epidemiological cycle of causative rickettsiae has not been fully accounted for in the Amazon region. This study investigates the presence of spotted fever group (SFG) Rickettsia spp. in free-living unfed ticks of the Amblyomma genus. The study was conducted in seven municipalities in Rondonia State, Brazil, where the main biomes are Amazon forest, Brazilian Savannah and their ecotones (areas of ecological tension between open ombrophilous forest and savannah). The following tick species were collected: Amblyomma cajennense (sensu lato) s.l., A. cajennense (sensu stricto) s.s., A. coelebs, A. naponense, A. oblongoguttatum, A. romitii, A. scalpturatum and A. sculptum. A total of 167 adults, 248 nymphs and 1004 larvae were subjected to DNA extraction and polymerase chain reaction (PCR) to determine the presence of SFG Rickettsia spp. PCR-positive samples included: one A. cajennense s.s. female and one A. cajennense s.l. male from a rural area in Vilhena Municipality; 10 nymphs and a sample of larvae of A. cajennense s.l. from a peri-urban area in Cacoal Municipality; and an A. oblongoguttatum adult male from a rural area of Pimenta Bueno Municipality. All sequences obtained exhibited 100% identity with Rickettsia amblyommatis sequences. This is the first confirmation of SFG Rickettsia in an A. oblongoguttatum tick. Furthermore, this is the first record of SFG Rickettsia in the municipalities targeted by this study. These results warn that SFG Rickettsia circulation poses a threat in Rondonia State (among Amazon-Savannah ecotones), and that this threat is increased by the fact that SFG Rickettsia infect a human-biting tick species hitherto unconfirmed as a vector. Copyright © 2018 Elsevier GmbH. All rights reserved.

Implications of Scientific Collaboration Networks on Studies of Aquatic Vertebrates in the Brazilian Amazon.

PubMed

Salinero, María Celeste; Michalski, Fernanda

2016-01-01

The quantity of wildlife extracted from the Amazon has increased in the past decades as a consequence of an increase in human population density and income growth. To evaluate the spatial distribution of studies on subsistence and/or commercial hunting conducted in the Brazilian Amazon, we selected eight mid-sized and large-bodied aquatic vertebrate species with a history of human exploitation in the region. We used a combination of searches in the gray and scientific literature from the past 24 years to provide an updated distributional map of studies on the target species. We calculated the distances between the study sites and the locations of the research institutes/universities that the first and last authors of the same study were affiliated to. For the period of 1990 to 2014, we found 105 studies on the subsistence and/or commercial hunting of aquatic vertebrates in the Brazilian Amazon in 271 locations that involved 43 institutions (37 Brazilian and 6 international). The spatial distribution of the studies across the Brazilian Amazon varied, but over 80% took place in the northeast and central Amazon, encompassing three States of the Legal Brazilian Amazon (Amazonas, 51.42%; Pará, 19.05%; and Amapá, 16.19%). Over half of the research study sites (52.91%) were within 500 km of the research institute/university of the first or last authors. Some research institutes/universities did not have any inter-institutional collaborations, while others collaborated with eight or more institutes. Some research institutes/universities conducted many studies, had an extensive collaboration network, and contributed greatly to the network of studies on Amazonian aquatic vertebrates. Our research contributes to the knowledge of studies on the subsistence and/or commercial hunting of the most exploited aquatic vertebrates of the Brazilian Amazon, illustrates the impact that collaboration networks have on research, and highlights potential areas for improvement and the generation of new collaborations.

Biomass burning losses of carbon estimated from ecosystem modeling and satellite data analysis for the Brazilian Amazon region

NASA Astrophysics Data System (ADS)

Potter, Christopher; Brooks Genovese, Vanessa; Klooster, Steven; Bobo, Matthew; Torregrosa, Alicia

To produce a new daily record of gross carbon emissions from biomass burning events and post-burning decomposition fluxes in the states of the Brazilian Legal Amazon (Instituto Brasileiro de Geografia e Estatistica (IBGE), 1991. Anuario Estatistico do Brasil, Vol. 51. Rio de Janeiro, Brazil pp. 1-1024). We have used vegetation greenness estimates from satellite images as inputs to a terrestrial ecosystem production model. This carbon allocation model generates new estimates of regional aboveground vegetation biomass at 8-km resolution. The modeled biomass product is then combined for the first time with fire pixel counts from the advanced very high-resolution radiometer (AVHRR) to overlay regional burning activities in the Amazon. Results from our analysis indicate that carbon emission estimates from annual region-wide sources of deforestation and biomass burning in the early 1990s are apparently three to five times higher than reported in previous studies for the Brazilian Legal Amazon (Houghton et al., 2000. Nature 403, 301-304; Fearnside, 1997. Climatic Change 35, 321-360), i.e., studies which implied that the Legal Amazon region tends toward a net-zero annual source of terrestrial carbon. In contrast, our analysis implies that the total source fluxes over the entire Legal Amazon region range from 0.2 to 1.2 Pg C yr -1, depending strongly on annual rainfall patterns. The reasons for our higher burning emission estimates are (1) use of combustion fractions typically measured during Amazon forest burning events for computing carbon losses, (2) more detailed geographic distribution of vegetation biomass and daily fire activity for the region, and (3) inclusion of fire effects in extensive areas of the Legal Amazon covered by open woodland, secondary forests, savanna, and pasture vegetation. The total area of rainforest estimated annually to be deforested did not differ substantially among the previous analyses cited and our own.

Implications of Scientific Collaboration Networks on Studies of Aquatic Vertebrates in the Brazilian Amazon

PubMed Central

Salinero, María Celeste; Michalski, Fernanda

2016-01-01

The quantity of wildlife extracted from the Amazon has increased in the past decades as a consequence of an increase in human population density and income growth. To evaluate the spatial distribution of studies on subsistence and/or commercial hunting conducted in the Brazilian Amazon, we selected eight mid-sized and large-bodied aquatic vertebrate species with a history of human exploitation in the region. We used a combination of searches in the gray and scientific literature from the past 24 years to provide an updated distributional map of studies on the target species. We calculated the distances between the study sites and the locations of the research institutes/universities that the first and last authors of the same study were affiliated to. For the period of 1990 to 2014, we found 105 studies on the subsistence and/or commercial hunting of aquatic vertebrates in the Brazilian Amazon in 271 locations that involved 43 institutions (37 Brazilian and 6 international). The spatial distribution of the studies across the Brazilian Amazon varied, but over 80% took place in the northeast and central Amazon, encompassing three States of the Legal Brazilian Amazon (Amazonas, 51.42%; Pará, 19.05%; and Amapá, 16.19%). Over half of the research study sites (52.91%) were within 500 km of the research institute/university of the first or last authors. Some research institutes/universities did not have any inter-institutional collaborations, while others collaborated with eight or more institutes. Some research institutes/universities conducted many studies, had an extensive collaboration network, and contributed greatly to the network of studies on Amazonian aquatic vertebrates. Our research contributes to the knowledge of studies on the subsistence and/or commercial hunting of the most exploited aquatic vertebrates of the Brazilian Amazon, illustrates the impact that collaboration networks have on research, and highlights potential areas for improvement and the generation of new collaborations. PMID:27352247

Deforestation, fire susceptibility, and potential tree responses to fire in the eastern Amazon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uhl, C.; Kauffman, J.B.

1990-04-01

In the state of Para, Brazil, in the eastern Amazon, the authors studied the potential for sustained fire events within four dominant vegetation cover types (undisturbed rain forest, selectively logged forest, second-growth forest, and open pasture), by measuring fuel availability, microclimate, and rates of fuel moisture loss. They also estimated the potential tree mortality that might result from a wide-scale Amazon forest fire by measuring the thermal properties of bark for all trees in a 5-ha stand of mature forest, followed by measurements of heat flux through bark during simulated fires. In pastures the average midday temperature was almost 10{degree}Cmore » greater and the average midday relative humidity was 30% lower than in primary forest. The most five-prone ecosystem was the open pasture followed by selectively logged forest, second growth forest, and undisturbed rain forest in which sustained combustion was not possible even after prolonged rainless periods. Even though the autogenic factors in primary forest of the eastern Amazon create a microclimate that virtually eliminates the probability of fire, they are currently a common event in disturbed areas of Amazonia. As many as 8 {times} 10{sup 6} ha burned in the Amazon Basin of Brazil in 1987 alone. In terms of current land-use patterns, altered microclimates, and fuel mass, there are also striking similarities between the eastern Amazon and East Kalimantan, Indonesia (the site of recent rain forest wildfires that burned 3.5 {times} 10{sup 6} ha).« less

Spatially and seasonally asymmetric responses of Amazon forests to El Niño

NASA Astrophysics Data System (ADS)

Mao, J.; Yan, B.; Dickinson, R. E.; Shi, X.; Ricciuto, D. M.; Norby, R. J.; Dai, Y.; Zhang, X.; McDowell, N.; Wu, J.

2017-12-01

El Niño Southern Oscillation (ENSO) events impose strong inter-annual signals on local climate changes and terrestrial ecosystem dynamics in many regions on the Earth especially tropical forests in the Amazon basin. However, much is still unknown regarding the vulnerability of tropical forests to ENSO effects, especially in a spatially-explicit context. Here, using satellite and ground observations with reanalysis data of climate variables, we analyzed the spatial and temporal patterns of plant growth in response to the warm phase of ENSO (i.e., El Niño), which resulted in precipitation anomaly (or drought) over a large area across the Amazon. We found that the influence of El Niño events on vegetation growth varied spatially and seasonally. During each season (dry or wet), the forests were divided into two sub-regions that were either controlled by precipitation or radiation. The boundaries between the two sub-regions were determined, which were distributed from northwest to southeast in the dry season and from northeast to southwest in the wet season. This result improves our understanding of the water and energy availability co-modulating the vegetation growth in Amazonia and the magnitude and direction of Amazon forests responding to drought.

[Economic evaluation of social technologies applied to health promotion: water supply by the SODIS System in riverside communities of the Brazilian Amazon].

PubMed

Lobo, Marco Aurélio Arbage; Lima, Dula Maria Bento de; Souza, Cezarina Maria Nobre; Nascimento, Waddle Almeida; Araújo, Leiliane Cristina Cardoso; Santos, Neucy Barreto dos

2013-07-01

The so-called social technologies have been widely used in many places around the world as a viable alternative for low-income populations to gain access to opportunities for employment and income and other aspects related to quality of life, including basic sanitation. This paper conducts a cost-benefit analysis of using a low cost technology for drinking water used in several countries, namely the SODIS system. The study was conducted in riverside communities living in the island area of Belem municipality, located in the Brazilian Amazon. Data were collected through questionnaires answered by families living on three islands: Jutuba, Nova and Urubuoca. The results were positive, considering the cost-benefit analysis of the project, which demonstrates the economic viability of using the SODIS system in the situation investigated.

A Theory of the Origin of the State

ERIC Educational Resources Information Center

Carneiro, Robert L.

1970-01-01

Suggests that states evolve in response to ecological or social circumscription, or resource concentration. When dense populations develop, fighting over land forces loser into political subordination or incorporation. This modification of coercive theories explain lack of state in Amazon basin and origin of Inca, Maya, Hwang Valley states.…

Response of Amazon Fires to the 2015/2016 El Niño and Evaluation of a Seasonal Fire Season Severity Forecast

NASA Astrophysics Data System (ADS)

Randerson, J. T.

2016-12-01

Recent work has established that year-to-year variability in drought and fire within the Amazon responds to a dual forcing from ocean-atmosphere interactions in the tropical Pacific and North Atlantic. Teleconnections between the Pacific and the Amazon are strongest between October and March, when El Niño contributes to below-average precipitation during the wet season. A reduced build-up of soil moisture during the wet season, in turn, may limit water availability and transpiration in tropical forests during the following dry season, lowering surface humidity, drying fuels, and allowing fires to spread more easily through the understory. The delayed influence of soil moisture through this land - atmosphere coupling provides a means to predict fire season severity 3-6 months before the onset of the dry season. With the aim of creating new opportunities for forest conservation, we have developed an experimental seasonal fire forecasting system for the Amazon. The 2016 fire season severity forecast, released in June by UCI and NASA, predicts unusually high risk across eastern Peru, northern Bolivia, and Brazil. Several surface and satellite data streams confirm that El Niño teleconnections had a significant impact on wet season hydrology within the Amazon. Rainfall observations from the Global Precipitation Climatology Centre provided evidence that cumulative precipitation deficits during August-April were 1 to 2 standard deviations below the long-term mean for most of the basin. These observations were corroborated by strong negative terrestrial water storage anomalies measured by the Gravity Recovery and Climate Experiment, and by fluorescence and vegetation index observations from other sensors that indicated elevated canopy stress. By August 3rd, satellite observations showed above average fire activity in most, but not all, forecast regions. Using additional satellite observations that become available later this year, we plan to describe the full spatial and temporal pattern of fires within the Amazon during the 2016 dry season and evaluate the success of our forecast. As a part of this analysis, we will compare fires from 2016 with other years of extreme drought (i.e., 2005 and 2010), and assess how trends in land use, including regional changes in deforestation, modify El Niño-driven fire risk.

Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management.

PubMed

Hegg, Jens C; Giarrizzo, Tommaso; Kennedy, Brian P

2015-01-01

Animal migrations provide important ecological functions and can allow for increased biodiversity through habitat and niche diversification. However, aquatic migrations in general, and those of the world's largest fish in particular, are imperiled worldwide and are often poorly understood. Several species of large Amazonian catfish carry out some of the longest freshwater fish migrations in the world, travelling from the Amazon River estuary to the Andes foothills. These species are important apex predators in the main stem rivers of the Amazon Basin and make up the region's largest fishery. They are also the only species to utilize the entire Amazon Basin to complete their life cycle. Studies indicate both that the fisheries may be declining due to overfishing, and that the proposed and completed dams in their upstream range threaten spawning migrations. Despite this, surprisingly little is known about the details of these species' migrations, or their life history. Otolith microchemistry has been an effective method for quantifying and reconstructing fish migrations worldwide across multiple spatial scales and may provide a powerful tool to understand the movements of Amazonian migratory catfish. Our objective was to describe the migratory behaviors of the three most populous and commercially important migratory catfish species, Dourada (Brachyplatystoma rousseauxii), Piramutaba (Brachyplatystoma vaillantii), and Piraíba (Brachyplatystoma filamentosum). We collected fish from the mouth of the Amazon River and the Central Amazon and used strontium isotope signatures ((87)Sr/(86)Sr) recorded in their otoliths to determine the location of early rearing and subsequent. Fish location was determined through discriminant function classification, using water chemistry data from the literature as a training set. Where water chemistry data was unavailable, we successfully in predicted (87)Sr/(86)Sr isotope values using a regression-based approach that related the geology of the upstream watershed to the Sr isotope ratio. Our results provide the first reported otolith microchemical reconstruction of Brachyplatystoma migratory movements in the Amazon Basin. Our results indicate that juveniles exhibit diverse rearing strategies, rearing in both upstream and estuary environments. This contrasts with the prevailing understanding that juveniles rear in the estuary before migrating upstream; however, it is supported by some fisheries data that has indicated the presence of alternate spawning and rearing life-histories. The presence of alternate juvenile rearing strategies may have important implications for conservation and management of the fisheries in the region.

Flow Estimate of Carbon Dioxide in a Amazon River Hydrological Station

NASA Astrophysics Data System (ADS)

Moura, J. M. S.; Ferreira, R. B., Jr.; Tapajós, R. P.

2014-12-01

Recent measurements in the Amazon suggest that the flow of CO2 in surface waters may reach the order of 1GT per year and isotopic analyzes suggest that this carbon is a direct result of organic matter degradation (OMD) in rivers and the measured concentration exceeds the value expected for there to be equilibrium with the atmosphere (Richey et al, 2002). This study aimed to measure and check the seasonal variability of CO2 fluxes in a range of six months (September 2013-February 2014) in the Strait Óbidos hydrological station located geographically in the coordinates 55 ° 1 '4 "S and 55 ° 31' 4" W. In addiction, it is intended to correlate the data with physical-chemical water parameters pH, dissolved oxygen (DO), and temperature and humidity. The method used for the measurement of CO2 concentration in the atmosphere-water interface is the floating chamber liked with an infrared gas analyzer (IRGA- Infrared Gas Analyzer). The physical-chemical parameters of water were measured using a multiparameter probe YSI Professional Plus model. The preliminary results shows values average CO2 flux was approximately 15.65 1,01ppm / m2s-1 for the months of September and October and between the months of November, 2013 and February 2014 the CO2 flux average was 4.40 + 1.94 ppm / m2s-1. In addiction to the high temperature in dry season, in the water column there is sufficient convection for the existence of gases transport from water to atmosphere, resulting in increase of exchange. Thus, the decreased amount of radiation and consequently the low temperatures in the humid period (on average 27.2 ° C) should affect the OMD in the river, responsible for the production of dissolved CO2. Keywords: CO2 flux, seasonal variability, amazon river

Determinants of Caregivers' Use and Adoption of Household Water Chlorination: A Qualitative Study with Peri-Urban Communities in the Peruvian Amazon.

PubMed

Rothstein, Jessica D; Leontsini, Elli; Olortegui, Maribel Paredes; Yori, Pablo Peñataro; Surkan, Pamela J; Kosek, Margaret

2015-09-01

The gap between the efficacy and the effectiveness of household water treatment in reducing diarrhea-related morbidity indicates the need for a better understanding of the determinants of long-term behavior change. To explore the barriers to drinking water chlorination in the Peruvian Amazon, where diarrhea is endemic among under-5 children, we conducted qualitative research with 23 caregivers from peri-urban communities of Iquitos, Peru. Our inquiry drew on the Transtheoretical Model of behavior change and the Integrated Behavioral Model for Water, Sanitation, and Hygiene to identify the most relevant contextual, psychosocial, and technological determinants of initial action and long-term adoption of chlorination. Our findings suggest that the decision to try out this practice resulted from the combined effect of knowledge of chlorination benefits and product availability and affordability. Progress from action to adoption was influenced by caretakers' understanding of dosage, the packaging of chlorine products, knowledge and skills for multipurpose laundry bleach, the taste of treated water, and reinforcement. This analysis suggests that a focus on these determinants and the household domain may help to improve the sustainability of future intervention efforts. © The American Society of Tropical Medicine and Hygiene.

Determinants of Caregivers' Use and Adoption of Household Water Chlorination: A Qualitative Study with Peri-urban Communities in the Peruvian Amazon

PubMed Central

Rothstein, Jessica D.; Leontsini, Elli; Olortegui, Maribel Paredes; Yori, Pablo Peñataro; Surkan, Pamela J.; Kosek, Margaret

2015-01-01

The gap between the efficacy and the effectiveness of household water treatment in reducing diarrhea-related morbidity indicates the need for a better understanding of the determinants of long-term behavior change. To explore the barriers to drinking water chlorination in the Peruvian Amazon, where diarrhea is endemic among under-5 children, we conducted qualitative research with 23 caregivers from peri-urban communities of Iquitos, Peru. Our inquiry drew on the Transtheoretical Model of behavior change and the Integrated Behavioral Model for Water, Sanitation, and Hygiene to identify the most relevant contextual, psychosocial, and technological determinants of initial action and long-term adoption of chlorination. Our findings suggest that the decision to try out this practice resulted from the combined effect of knowledge of chlorination benefits and product availability and affordability. Progress from action to adoption was influenced by caretakers' understanding of dosage, the packaging of chlorine products, knowledge and skills for multipurpose laundry bleach, the taste of treated water, and reinforcement. This analysis suggests that a focus on these determinants and the household domain may help to improve the sustainability of future intervention efforts. PMID:26175028

Nest placement of the giant Amazon river turtle, Podocnemis expansa, in the Araguaia River, Goiás State, Brazil.

PubMed

Ferreira, Paulo Dias Júnior; Castro, Paulo de Tarso Amorim

2005-05-01

The giant Amazon river turtle (Podocnemis expansa) nests on extensive sand bars on the margins and interior of the channel during the dry season. The high concentration of nests in specific points of certain beaches indicates that the selection of nest placement is not random but is related to some geological aspects, such as bar margin inclination and presence of a high, sandy platform. The presence of access channels to high platform points or ramp morphology are decisive factors in the choice of nesting areas. The eroded and escarped margins of the beaches hinder the Amazon river turtle arriving at the most suitable places for nesting. Through the years, changes in beach morphology can alter nest distribution.

Rivers and Floodplains as Key Components of Global Terrestrial Water Storage Variability

NASA Astrophysics Data System (ADS)

Getirana, Augusto; Kumar, Sujay; Girotto, Manuela; Rodell, Matthew

2017-10-01

This study quantifies the contribution of rivers and floodplains to terrestrial water storage (TWS) variability. We use state-of-the-art models to simulate land surface processes and river dynamics and to separate TWS into its main components. Based on a proposed impact index, we show that surface water storage (SWS) contributes 8% of TWS variability globally, but that contribution differs widely among climate zones. Changes in SWS are a principal component of TWS variability in the tropics, where major rivers flow over arid regions and at high latitudes. SWS accounts for 22-27% of TWS variability in both the Amazon and Nile Basins. Changes in SWS are negligible in the Western U.S., Northern Africa, Middle East, and central Asia. Based on comparisons with Gravity Recovery and Climate Experiment-based TWS, we conclude that accounting for SWS improves simulated TWS in most of South America, Africa, and Southern Asia, confirming that SWS is a key component of TWS variability.

Unofficial Road Building in the Brazilian Amazon: Dilemmas and Models for Road Governance

NASA Technical Reports Server (NTRS)

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

2007-01-01

Unofficial roads form dense networks in landscapes, generating a litany of negative ecological outcomes, but unofficial roads in frontier areas are also instrumental in local livelihoods and community development. This trade-off poses dilemmas for the governance of unofficial roads. Unofficial road building in frontier areas of the Brazilian Amazon illustrates the challenges of 'road governance.' Both state-based and community based governance models exhibit important liabilities for governing unofficial roads. Whereas state-based governance has experienced difficulties in adapting to specific local contexts and interacting effectively with local interest groups, community-based governance has a mixed record owing to social inequalities and conflicts among local interest groups. A state-community hybrid model may offer more effective governance of unofficial road building by combining the oversight capacity of the state with locally grounded community management via participatory decision-making.

Natural variation of selenium in Brazil nuts and soils from the Amazon region.

PubMed

Silva Junior, E C; Wadt, L H O; Silva, K E; Lima, R M B; Batista, K D; Guedes, M C; Carvalho, G S; Carvalho, T S; Reis, A R; Lopes, G; Guilherme, L R G

2017-12-01

Brazil nut tree (Bertholletia excelsa) is native of the Amazon rainforest. Brazil nuts are consumed worldwide and are known as the richest food source of selenium (Se). Yet, the reasoning for such Se contents is not well stablished. We evaluated the variation in Se concentration of Brazil nuts from Brazilian Amazon basin, as well as soil properties, including total Se concentration, of the soils sampled directly underneath the trees crown, aiming to investigate which soil properties influence Se accumulation in the nuts. The median Se concentration in Brazil nuts varied from 2.07 mg kg - 1 (in Mato Grosso state) to 68.15 mg kg - 1 (in Amazonas state). Therefore, depending on its origin, a single Brazil nut could provide from 11% (in the Mato Grosso state) up to 288% (in the Amazonas state) of the daily Se requirement for an adult man (70 μg). The total Se concentration in the soil also varied considerably, ranging from <65.76 to 625.91 μg kg - 1 , with highest Se concentrations being observed in soil samples from the state of Amazonas. Se accumulation in Brazil nuts generally increased in soils with higher total Se content, but decreased under acidic conditions in the soil. This indicates that, besides total soil Se concentration, soil acidity plays a major role in Se uptake by Brazil nut trees, possibly due to the importance of this soil property to Se retention in the soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

Testing Wallace's intuition: water type, reproductive isolation and divergence in an Amazonian fish.

PubMed

Pires, Tiago H S; Borghezan, Elio A; Machado, Valeria N; Powell, Daniel L; Röpke, Cristhiana P; Oliveira, Claudio; Zuanon, Jansen; Farias, Izeni P

2018-06-01

Alfred Russel Wallace proposed classifying Amazon rivers based on their colour and clarity: white, black and clear water. Wallace also proposed that black waters could mediate diversification and yield distinct fish species. Here, we bring evidence of speciation mediated by water type in the sailfin tetra (Crenuchus spilurus), a fish whose range encompasses rivers of very distinct hydrochemical conditions. Distribution of the two main lineages concords with Wallace's water types: one restricted to the acidic and nutrient-poor waters of the Negro River (herein Rio Negro lineage) and a second widespread throughout the remaining of the species' distribution (herein Amazonas lineage). These lineages occur over a very broad geographical range, suggesting that despite occurring in regions separated by thousands of kilometres, individuals of the distinct lineages fail to occupy each other's habitats, hundreds of metres apart and not separated by physical barrier. Reproductive isolation was assessed in isolated pairs exposed to black-water conditions. All pairs with at least one individual of the lineage not native to black waters showed significantly lower spawning success, suggesting that the water type affected the fitness and contributed to reproductive isolation. Our results endorse Wallace's intuition and highlight the importance of ecological factors in shaping diversity of the Amazon fish fauna. © 2018 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2018 European Society For Evolutionary Biology.

Deforestation and Malaria on the Amazon Frontier: Larval Clustering of Anopheles darlingi (Diptera: Culicidae) Determines Focal Distribution of Malaria

PubMed Central

Barros, Fábio S. M.; Honório, Nildimar A.

2015-01-01

We performed bimonthly mosquito larval collections during 1 year, in an agricultural settlement in the Brazilian Amazon, as well as an analysis of malaria incidence in neighboring houses. Water collections located at forest fringes were more commonly positive for Anopheles darlingi larvae and Kulldorff spatial analysis pinpointed significant larval clusters at sites directly beneath forest fringes, which were called larval “hotspots.” Remote sensing identified 43 “potential” hotspots. Sampling of these areas revealed an 85.7% positivity rate for A. darlingi larvae. Malaria was correlated with shorter distances to potential hotpots and settlers living within 400 m of potential hotspots had a 2.60 higher risk of malaria. Recently arrived settlers, usually located closer to the tip of the triangularly shaped deforestation imprints of side roads, may be more exposed to malaria due to their proximity to the forest fringe. As deforestation progresses, transmission decreases. However, forest remnants inside deforested areas conferred an increased risk of malaria. We propose a model for explaining frontier malaria in the Amazon: because of adaptation of A. darlingi to the forest fringe ecotone, humans are exposed to an increased transmission risk when in proximity to these areas, especially when small dams are created on naturally running water collections. PMID:26416110

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

PubMed Central

San, S; Armstrong, B; Cordoba, J; Stephens, C

2001-01-01

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


Keywords: cancer; oil; Amazon; Ecuador PMID:11452046

Incorporation of a dynamic root distribution into CLM4.5: Evaluation of carbon and water fluxes over the Amazon

NASA Astrophysics Data System (ADS)

Wang, Yuanyuan; Xie, Zhenghui; Jia, Binghao

2016-09-01

Roots are responsible for the uptake of water and nutrients by plants and have the plasticity to dynamically respond to different environmental conditions. However, most land surface models currently prescribe rooting profiles as a function only of vegetation type, with no consideration of the surroundings. In this study, a dynamic rooting scheme, which describes root growth as a compromise between water and nitrogen availability, was incorporated into CLM4.5 with carbon-nitrogen (CN) interactions (CLM4.5-CN) to investigate the effects of a dynamic root distribution on eco-hydrological modeling. Two paired numerical simulations were conducted for the Tapajos National Forest km83 (BRSa3) site and the Amazon, one using CLM4.5-CN without the dynamic rooting scheme and the other including the proposed scheme. Simulations for the BRSa3 site showed that inclusion of the dynamic rooting scheme increased the amplitudes and peak values of diurnal gross primary production (GPP) and latent heat flux (LE) for the dry season, and improved the carbon (C) and water cycle modeling by reducing the RMSE of GPP by 0.4 g C m-2 d-1, net ecosystem exchange by 1.96 g C m-2 d-1, LE by 5.0 W m-2, and soil moisture by 0.03 m3 m-3, at the seasonal scale, compared with eddy flux measurements, while having little impact during the wet season. For the Amazon, regional analysis also revealed that vegetation responses (including GPP and LE) to seasonal drought and the severe drought of 2005 were better captured with the dynamic rooting scheme incorporated.

Local and remote climatic impacts due to land use degradation in the Amazon "Arc of Deforestation"

NASA Astrophysics Data System (ADS)

Silva, Maria Elisa Siqueira; Pereira, Gabriel; da Rocha, Rosmeri Porfírio

2016-08-01

Many numerical studies, among them, global and regional models, have been used to simulate climatic impact due to Amazon deforestation. Most of them did not consider deforestation as usually observed and the induced dynamic changes. The present study explores the physical impacts due to Amazon deforestation by considering local and remote changes in the circulation and thermodynamics. For this, numerical experiments were conducted with RegCM3 using a relatively fine horizontal grid spacing (50 km), more realistic deforested areas (similar to the highway-network-shaped), and an updated land use map. The studied period was 2001-2006 October-March. As in most previous studies focusing on Amazon deforestation, the RegCM3-simulated air temperature increases over degraded areas, ranging from 1.0 to 2.5 °C, and precipitation decreases of around 10 %. This result is mainly related to depletion in evapotranspiration rates provided by lesser soil water extraction by the degraded vegetation. The weakening of upward motion in the mid-upper troposphere is an associated mechanism that explains the precipitation decrease after Amazon deforestation. A new result is the simulated precipitation increase, about 10 %, over the eastern South America and the adjacent South Atlantic Ocean. In these areas, the precipitation increase during October-March is associated with intensification of upper-level high pressure (the Bolivian high) coupled with negative geopotential height anomalies southeastward of the center of the high.

Anthropogenic Effects on the Mixing State of Aerosols over Manaus during the Green Ocean Amazon (GoAmazon) Campaign

NASA Astrophysics Data System (ADS)

Fraund, M. W.; Pham, D.; Harder, T.; O'Brien, R.; Wang, B.; Laskin, A.; Gilles, M. K.; Moffet, R.

2015-12-01

The role that anthropogenic aerosols play in cloud formation is uncertain and contributes largely to the uncertainty in predicting future climate. One region of particular importance is the Amazon rainforest, which accounts for over half of the world's rainforest. During GoAmazon2014/15 IOP2, aerosol samples were collected at multiple sites in and around the rapidly growing industrial city of Manaus in the Amazon basin. Manaus is of scientific interest due to the pristine nature of the surrounding rainforest and the high levels of pollution coming from the city in the form of SO2, NOx, and soot. Some sites, such as the Terrestrial Ecosystem Science center (TES, also designated ZF2) located to the north of Manaus, represent air masses which have not interacted with emissions from the city. The comparison of pristine atmosphere with heavy pollution allows both for the determination of a natural baseline level of pollutants, as well as the study of pollutant's impact on the conversion of biogenic volatile organic compounds to secondary organic aerosols. Towards this goal, samples from ZF2 and other unpolluted sites will be compared to samples from the Atmospheric Radiation Measurement (ARM) climate research facility in Manacapuru (T3), which is southwest (downwind) of Manaus. Spatially resolved spectra were recorded at the sub-particle level using scanning transmission X-ray microscopy (STXM) at the carbon, nitrogen, and oxygen K-absorption edges. Scanning electron microscopy coupled with energy dispersive x-ray spectroscopy (SEM/EDX) was also performed on to characterize higher Z elements. These two techniques together will allow for the mass fraction of atmospherically relevant elements to be determined on a per-particle basis. We will apply established procedures to determine the mixing state index for samples collected at ZF2 and T3 using elemental mass fractions. Preliminary results will be presented which focus on investigating the difference between mixing state indices of aerosol samples collected at these two sites, due to anthropogenic emissions. The ultimate goal is to use the mixing state index as a parameter which enables changes in the composition of aerosols to be modeled with more certainty as well enabling a quantification of the anthropogenic effects on natural rainforest atmosphere.

Pharmacokinetics after oral and intravenous administration of a single dose of tramadol hydrochloride to Hispaniolan Amazon parrots (Amazona ventralis).

PubMed

Souza, Marcy J; Sanchez-Migallon Guzman, David; Paul-Murphy, Joanne R; Cox, Sherry K

2012-08-01

To determine pharmacokinetics after IV and oral administration of a single dose of tramadol hydrochloride to Hispaniolan Amazon parrots (Amazona ventralis). 9 healthy adult Hispaniolan Amazon parrots (3 males, 5 females, and 1 of unknown sex). Tramadol (5 mg/kg, IV) was administered to the parrots. Blood samples were collected from -5 to 720 minutes after administration. After a 3-week washout period, tramadol (10 and 30 mg/kg) was orally administered to parrots. Blood samples were collected from -5 to 1,440 minutes after administration. Three formulations of oral suspension (crushed tablets in a commercially available suspension agent, crushed tablets in sterile water, and chemical-grade powder in sterile water) were evaluated. Plasma concentrations of tramadol and its major metabolites were measured via high-performance liquid chromatography. Mean plasma tramadol concentrations were > 100 ng/mL for approximately 2 to 4 hours after IV administration of tramadol. Plasma concentrations after oral administration of tramadol at a dose of 10 mg/kg were < 40 ng/mL for the entire time period, but oral administration at a dose of 30 mg/kg resulted in mean plasma concentrations > 100 ng/mL for approximately 6 hours after administration. Oral administration of the suspension consisting of the chemical-grade powder resulted in higher plasma tramadol concentrations than concentrations obtained after oral administration of the other 2 formulations; however, concentrations differed significantly only at 120 and 240 minutes after administration. Oral administration of tramadol at a dose of 30 mg/kg resulted in plasma concentrations (> 100 ng/mL) that have been associated with analgesia in Hispaniolan Amazon parrots.

Multi-temporal flood mapping and satellite altimetry used to evaluate the flood dynamics of the Bolivian Amazon wetlands

NASA Astrophysics Data System (ADS)

Ovando, A.; Martinez, J. M.; Tomasella, J.; Rodriguez, D. A.; von Randow, C.

2018-07-01

The Bolivian Amazon wetlands are extensive floodplains distributed over the Mamore, Beni, Madre de Dios and Guapore Rivers. Located within the upper Madeira River Basin, the wetlands play important roles in regulating the biogeochemical processes and hydrological cycle of the region. In addition, they have major ecological and hydrological relevance for the entire Amazon Basin. These wetlands are characterized by the occurrence of episodic floods that result from contrasting hydro-meteorological processes in the Andean Mountain region, the piedmont area and the Amazon lowlands. In this study, we characterized the flood dynamics of the region using multi-temporal flood mapping based on optical altimetry (MODIS - Moderate Resolution Imaging Spectroradiometer - M*D09A1) and satellite altimetry (ENVISAT RA-2 and SARAL AltiKa altimeters). This study provides new insights regarding the frequency, magnitude and spatial distribution of exogenous floods, which are created by flood waves from the Andes; and endogenous floods, which result from runoff originating in the lowlands. The maximum extent of flooding during 2001-2014 was 43144 km2 in the Mamore Basin and 34852 km2 in the Guapore Basin, and the total surface water storage in these floodplains reached 94 km3. The regionalization of flood regimes based on water stage time series signatures allowed those regions that are exposed to frequent floods, which are generally located along rivers without a direct connection with the Andes, to be distinguished from floodplains that are more dependent on flood waves originating in the Andes and its piedmonts. This information is of great importance for understanding the roles of these wetlands in the provision of ecosystem services.

Determining risk for severe leptospirosis by molecular analysis of environmental surface waters for pathogenic Leptospira.

PubMed

Ganoza, Christian A; Matthias, Michael A; Collins-Richards, Devon; Brouwer, Kimberly C; Cunningham, Calaveras B; Segura, Eddy R; Gilman, Robert H; Gotuzzo, Eduardo; Vinetz, Joseph M

2006-08-01

Although previous data indicate that the overall incidence of human leptospirosis in the Peruvian Amazon is similar in urban and rural sites, severe leptospirosis has been observed only in the urban context. As a potential explanation for this epidemiological observation, we tested the hypothesis that concentrations of more virulent Leptospira would be higher in urban than in rural environmental surface waters. A quantitative real-time PCR assay was used to compare levels of Leptospira in urban and rural environmental surface waters in sites in the Peruvian Amazon region of Iquitos. Molecular taxonomic analysis of a 1,200-bp segment of the leptospiral 16S ribosomal RNA gene was used to identify Leptospira to the species level. Pathogenic Leptospira species were found only in urban slum water sources (Fisher's exact test; p = 0.013). The concentration of pathogen-related Leptospira was higher in urban than rural water sources (approximately 10(3) leptospires/ml versus 0.5 x 10(2) leptospires/ml; F = 8.406, p < 0.05). Identical 16S rRNA gene sequences from Leptospira interrogans serovar Icterohaemorrhagiae were found in urban slum market area gutter water and in human isolates, suggesting a specific mode of transmission from rats to humans. In a prospective, population-based study of patients presenting with acute febrile illness, isolation of L. interrogans-related leptospires from humans was significantly associated with urban acquisition (75% of urban isolates); human isolates of other leptospiral species were associated with rural acquisition (78% of rural isolates) (chi-square analysis; p < 0.01). This distribution of human leptospiral isolates mirrored the distribution of leptospiral 16S ribosomal gene sequences in urban and rural water sources. Our findings data support the hypothesis that urban severe leptospirosis in the Peruvian Amazon is associated with higher concentrations of more pathogenic leptospires at sites of exposure and transmission. This combined quantitative and molecular taxonomical risk assessment of environmental surface waters is globally applicable for assessing risk for leptospiral infection and severe disease in leptospirosis-endemic regions.

Determining Risk for Severe Leptospirosis by Molecular Analysis of Environmental Surface Waters for Pathogenic Leptospira

PubMed Central

Collins-Richards, Devon; Brouwer, Kimberly C; Cunningham, Calaveras B; Segura, Eddy R; Gilman, Robert H; Gotuzzo, Eduardo; Vinetz, Joseph M

2006-01-01

Background Although previous data indicate that the overall incidence of human leptospirosis in the Peruvian Amazon is similar in urban and rural sites, severe leptospirosis has been observed only in the urban context. As a potential explanation for this epidemiological observation, we tested the hypothesis that concentrations of more virulent Leptospira would be higher in urban than in rural environmental surface waters. Methods and Findings A quantitative real-time PCR assay was used to compare levels of Leptospira in urban and rural environmental surface waters in sites in the Peruvian Amazon region of Iquitos. Molecular taxonomic analysis of a 1,200-bp segment of the leptospiral 16S ribosomal RNA gene was used to identify Leptospira to the species level. Pathogenic Leptospira species were found only in urban slum water sources (Fisher's exact test; p = 0.013). The concentration of pathogen-related Leptospira was higher in urban than rural water sources (~103 leptospires/ml versus 0.5 × 102 leptospires/ml; F = 8.406, p < 0.05). Identical 16S rRNA gene sequences from Leptospira interrogans serovar Icterohaemorrhagiae were found in urban slum market area gutter water and in human isolates, suggesting a specific mode of transmission from rats to humans. In a prospective, population-based study of patients presenting with acute febrile illness, isolation of L. interrogans-related leptospires from humans was significantly associated with urban acquisition (75% of urban isolates); human isolates of other leptospiral species were associated with rural acquisition (78% of rural isolates) (chi-square analysis; p < 0.01). This distribution of human leptospiral isolates mirrored the distribution of leptospiral 16S ribosomal gene sequences in urban and rural water sources. Conclusions Our findings data support the hypothesis that urban severe leptospirosis in the Peruvian Amazon is associated with higher concentrations of more pathogenic leptospires at sites of exposure and transmission. This combined quantitative and molecular taxonomical risk assessment of environmental surface waters is globally applicable for assessing risk for leptospiral infection and severe disease in leptospirosis-endemic regions. PMID:16933963

Biomass burning emissions of reactive gases estimated from satellite data analysis and ecosystem modeling for the Brazilian Amazon region

NASA Astrophysics Data System (ADS)

Potter, Christopher; Brooks-Genovese, Vanessa; Klooster, Steven; Torregrosa, Alicia

2002-10-01

To produce a new daily record of trace gas emissions from biomass burning events for the Brazilian Legal Amazon, we have combined satellite advanced very high resolution radiometer (AVHRR) data on fire counts together for the first time with vegetation greenness imagery as inputs to an ecosystem biomass model at 8 km spatial resolution. This analysis goes beyond previous estimates for reactive gas emissions from Amazon fires, owing to a more detailed geographic distribution estimate of vegetation biomass, coupled with daily fire activity for the region (original 1 km resolution), and inclusion of fire effects in extensive areas of the Legal Amazon (defined as the Brazilian states of Acre, Amapá, Amazonas, Maranhao, Mato Grosso, Pará, Rondônia, Roraima, and Tocantins) covered by open woodland, secondary forests, savanna, and pasture vegetation. Results from our emissions model indicate that annual emissions from Amazon deforestation and biomass burning in the early 1990s total to 102 Tg yr-1 carbon monoxide (CO) and 3.5 Tg yr-1 nitrogen oxides (NOx). Peak daily burning emissions, which occurred in early September 1992, were estimated at slightly more than 3 Tg d-1for CO and 0.1 Tg d-1for NOx flux to the atmosphere. Other burning source fluxes of gases with relatively high emission factors are reported, including methane (CH4), nonmethane hydrocarbons (NMHC), and sulfur dioxide (SO2), in addition to total particulate matter (TPM). We estimate the Brazilian Amazon region to be a source of between one fifth and one third for each of these global emission fluxes to the atmosphere. The regional distribution of burning emissions appears to be highest in the Brazilian states of Maranhao and Tocantins, mainly from burning outside of moist forest areas, and in Pará and Mato Grosso, where we identify important contributions from primary forest cutting and burning. These new daily emission estimates of reactive gases from biomass burning fluxes are designed to be used as detailed spatial and temporal inputs to computer models and data analysis of tropospheric chemistry over the tropical region.

The geochemistry of mercury in central Amazonian soils developed on the Alter-do-Chão formation of the lower Tapajós River Valley, Pará state, Brazil.

PubMed

Roulet, M; Lucotte, M; Saint-Aubin, A; Tran, S; Rhéault, I; Farella, N; De Jesus Da silva, E; Dezencourt, J; Sousa Passos, C J; Santos Soares, G; Guimarães, J R; Mergler, D; Amorim, M

1998-11-03

In an oxisol-spodosol system developed on the terrestrial surface of the lower Tapajós Valley, the determination of total mercury (Hg), organic carbon (C), iron and aluminum oxy-hydroxide (Fe(cdb) and Al(cdb)) concentrations in the surface soil horizons are used to characterise the geochemical processes controlling the accumulation of Hg in soils under natural vegetation cover and in deforested and cultivated sites. Oxisols from the plateau have homogeneous and relatively high background Hg contents and burdens constituting an important natural reservoir of Hg for the region (90-210 ng/g dry wt. and 19-33 mg/m2 for the first 20 cm). The Fe(cdb) and Al(cdb) contents associated with the fine fraction (< 63 microns) of the soil suggest that oxy-hydroxides and, particularly Al-substituted Fe oxy-hydroxides, control the Hg concentrations observed in all of the soils of the study region. Consequently, the geochemistry of these minerals along the slopes governs the accumulation or the release of the Hg according to the natural evolution of the soil cover and/or following the degradation of soils by erosion after deforestation and cultivation. These observations have important implications for the interpretation of Hg contamination patterns observed in Amazonian aquatic systems that could be linked to different drainage sources of Hg from the terrestrial surface. The sandification and podzolisation that is characteristic of the evolution of numerous pedological systems in the equatorial Amazon could be responsible for exportation of the naturally accumulated Hg, as for other metals, by acidic complexation and migration to the black waters of the Amazon. In the central Amazon region, as a result of the fragility of the soil cover, deforestation and cultivation, affecting principally the superficial soil, promote the selective erosion of fine particles enriched in oxides and Hg. The erosion of soil could be responsible for an important release of Hg, transported in particulate form by drainage waters.

An Object-Based Machine Learning Classification Procedure for Mapping Impoundments in Brazil's Amazon-Cerrado Agricultural Frontier

NASA Astrophysics Data System (ADS)

Solvik, K.; Macedo, M.; Graesser, J.; Lathuilliere, M. J.

2017-12-01

Large-scale agriculture and cattle ranching in Brazil has driving the creation of tens of thousands of small stream impoundments to provide water for crops and livestock. These impoundments are a source of methane emissions and have significant impacts on stream temperature, connectivity, and water use over a large region. Due to their large numbers and small size, they are difficult to map using conventional methods. Here, we present a two-stage object-based supervised classification methodology for identifying man-made impoundments in Brazil. First, in Google Earth Engine pixels are classified as water or non-water using satellite data and HydroSHEDS products as predictors. Second, using Python's scikit-learn and scikit-image modules the water objects are classified as man-made or natural based on a variety of shape and spectral properties. Both classifications are performed by a random forest classifier. Training data is acquired by visually identifying impoundments and natural water bodies using high resolution satellite imagery from Google Earth.This methodology was applied to the state of Mato Grosso using a cloud-free mosaic of Sentinel 1 (10m resolution) radar and Sentinel 2 (10-20m) multispectral data acquired during the 2016 dry season. Independent test accuracy was estimated at 95% for the first stage and 93% for the second. We identified 54,294 man-made impoundments in Mato Grosso in 2016. The methodology is generalizable to other high resolution satellite data and has been tested on Landsat 5 and 8 imagery. Applying the same approach to Landsat 8 images (30 m), we identified 35,707 impoundments in the 2015 dry season. The difference in number is likely because the coarser-scale imagery fails to detect small (< 900 m2) objects. On-going work will apply this approach to satellite time series for the entire Amazon-Cerrado frontier, allowing us to track changes in the number, size, and distribution of man-made impoundments. Automated impoundment mapping over large areas may help with management of streams in agricultural landscapes in Brazil and other tropical regions.

Road building, land use and climate change: prospects for environmental governance in the Amazon.

PubMed

Perz, Stephen; Brilhante, Silvia; Brown, Foster; Caldas, Marcellus; Ikeda, Santos; Mendoza, Elsa; Overdevest, Christine; Reis, Vera; Reyes, Juan Fernando; Rojas, Daniel; Schmink, Marianne; Souza, Carlos; Walker, Robert

2008-05-27

Some coupled land-climate models predict a dieback of Amazon forest during the twenty-first century due to climate change, but human land use in the region has already reduced the forest cover. The causation behind land use is complex, and includes economic, institutional, political and demographic factors. Pre-eminent among these factors is road building, which facilitates human access to natural resources that beget forest fragmentation. While official government road projects have received considerable attention, unofficial road building by interest groups is expanding more rapidly, especially where official roads are being paved, yielding highly fragmented forest mosaics. Effective governance of natural resources in the Amazon requires a combination of state oversight and community participation in a 'hybrid' model of governance. The MAP Initiative in the southwestern Amazon provides an example of an innovative hybrid approach to environmental governance. It embodies a polycentric structure that includes government agencies, NGOs, universities and communities in a planning process that links scientific data to public deliberations in order to mitigate the effects of new infrastructure and climate change.

Petrobras eyes LNG project in Amazon region

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-08-07

The Brazilian state oil company has proved gas reserves in the Rio Urucu area of the Amazon jungle totaling 1.84 tcf. That compares with 3.08 tcf contained in the offshore Campos basin, source of most of Brazil`s oil and gas production. The environmentally sensitive Urucu region is one of the most dense, remote jungles in the world. Because of environmental concerns about pipelines in the rain forest and a government emphasis on boosting the natural gas share of Brazil`s energy mix, a small liquefied natural gas project is shaping up as the best option for developing and marketing Urucu gas.more » The amazon campaign underscores a government initiative to boost Brazilian consumption of natural gas. In Brazil natural gas accounts for only 4% of primary energy consumption. Some years ago, the government set an official goal of boosting the gas share of the primary energy mix to 10% by 2000. The paper discusses current drilling activities, gas production and processing, the logistics of the upper Amazon, and gas markets.« less

[Universal health systems and territory: challenges for a regional policy in the Brazilian Legal Amazon].

PubMed

Viana, Ana Luiza d'Avila; Machado, Cristiani Vieira; Baptista, Tatiana Wargas de Faria; Lima, Luciana Dias de; Mendonça, Maria Helena Magalhães de; Heimann, Luiza S; Albuquerque, Mariana Vercesi; Iozzi, Fabíola Lana; David, Virna Carvalho; Ibañez, Pablo; Frederico, Samuel

2007-01-01

This article presents the results of a study on Federal health policy in the Brazilian Legal Amazon (BLA) from 2003 to 2005, aimed at backing the development of regional health policies. The region has peculiar dynamics, an extensive border area, and adverse social indicators. The methodology included documental and financial analysis, participatory observation, interviews with heads of various Federal Ministries and State and Municipal health secretaries from the BLA; characterization of geographic situations in the BLA; and field studies in 15 municipalities. Institutional consolidation of health policy proved to be low in the Amazon during the study period, due to structural, institutional, and political difficulties. The identification of six geographic situations was useful for systematizing land use differences with repercussions on health, and which should be considered when implementing public policies. There is a certain gap between Federal actions and territorial dynamics, expressed as a mismatch between the current policy and its recognition by local administrators. In addition to establishing a regional policy for the Amazon, there is an evident need for differentiated policies within the region.

Soil-transmitted helminth infections and nutritional status in Ecuador: findings from a national survey and implications for control strategies.

PubMed

Moncayo, Ana L; Lovato, Raquel; Cooper, Philip J

2018-04-28

The estimation of prevalence and intensity of soil-transmitted helminth (STH) infections at a country-level is an essential prerequisite for the implementation of a rational control programme. The aim of this present study was to estimate the prevalence and distribution of STH infections and malnutrition in school-age children in rural areas of Ecuador. Cross-sectional study from October 2011 to May 2012. Eighteen rural schools were randomly selected from the three ecological regions of Ecuador (coastal, highlands and Amazon basin). 920 children aged 6-16 years. Prevalence and intensity of STH infections associated with malnutrition (thinness/wasting or stunting). The results showed that 257 (27.9%) children were infected with at least one STH parasite. The prevalence of Trichuris trichiura , Ascaris lumbricoides and hookworm was 19.3%, 18.5% and 5.0%, respectively. Malnutrition was present in 14.2% of children and most common was stunting (12.3%). Compared with other regions, schoolchildren in the Amazon region had the highest STH prevalence (58.9%) of which a greater proportion of infections were moderate/heavy intensity (45.6%) and had the highest prevalence of malnutrition (20.4%). A positive association was observed between moderate to heavy infections with A. lumbricoides and malnutrition (adjusted OR 1.85, 95% CI 1.04 to 3.31, p=0.037). Our estimate of the prevalence of STH infections of 27.9% at a national level in Ecuador is lower than suggested by previous studies. Our data indicate that schoolchildren living in the Amazon region have a greater risk of STH infection and stunting compared with children from other regions. The implementation of school-based preventive chemotherapy and nutritional supplement programmes within the Amazon region should be prioritised. Long-term control strategies require improvements in water, sanitation and hygiene. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Phylogeography of the dark fruit-eating bat Artibeus obscurus in the Brazilian Amazon.

PubMed

Ferreira, Wallax Augusto Silva; Borges, Bárbara do Nascimento; Rodrigues-Antunes, Symara; de Andrade, Fernanda Atanaena Gonçalves; Aguiar, Gilberto Ferreira de Souza; de Sousa e Silva-Junior, José; Marques-Aguiar, Suely Aparecida; Harada, Maria Lúcia

2014-01-01

Artibeus obscurus (Mammalia: Chiroptera) is endemic to South America, being found in at least 18 Brazilian states. Recent studies revealed that different populations of this genus present distinct phylogeographic patterns; however, very little is known on the population genetics structure of A. obscurus in the Amazon rainforest. Here, using a fragment (1010bp) of the mitochondrial gene cytochrome b from 87 samples, we investigated patterns of genetic divergence among populations of A. obscurus from different locations in the Brazilian Amazon rainforest and compared them with other Brazilian and South American regions. Analysis of molecular variance (AMOVA), fixation index (Fst) analysis, and phylogeographic patterns showed divergence between two major monophyletic groups, each one corresponding to a geographic region associated with the Atlantic and Amazon forest biomes. The Atlantic forest clusters formed a monophyletic group with a high bootstrap support and a fragmented distribution that follows the pattern predicted by the Refuge Theory. On the other hand, a different scenario was observed for the Amazon forest, where no fragmentation was identified. The AMOVA results revealed a significant geographic heterogeneity in the distribution of genetic variation, with 70% found within populations across the studied populations (Fst values ranging from 0.05864 to 0.09673; φST = 0.55). The intrapopulational analysis revealed that one population (Bragança) showed significant evidence of population expansion, with the formation of 2 distinct phylogroups, suggesting the occurrence of a subspecies or at least a different population in this region. These results also suggest considerable heterogeneity for A. obscurus in the Amazon region.

Is the Amazon Rainforest Drying Out?

NASA Astrophysics Data System (ADS)

Saatchi, S.; Xu, L.; Bloom, A. A.; Konings, A. G.; Yang, Y.; Aragão, L. E.; Fu, R.; Worden, J. R.; Schimel, D.

2017-12-01

Hotter droughts are the emerging characteristics of recent climate conditions, causing increased aridity over many land areas, broad-scale die-off, and pervasive mortality in forest ecosystems globally. Using a suite of eco-hydrological measurements from satellite observations combined with ecosystem data assimilation model, we show the Amazon forests, under recent changes in climate, have been consistently losing water in vegetation from increased leaf temperature. These long-term changes have caused a decline in evapotranspiration with consequences of changing the seasonality of precipitation by increasing the dry season length and delaying the wet season arrival. Three severe droughts (2005, 2010, 2015), occurring on the background of this long-term warming have an unprecedented legacy resulting in longer delays in recharging of water storage and recovery of forests after drought induced disturbances (4-5 years after each drought). The paper discusses the evidences of eco-hydrological changes pointing to the drying of forests of Amazonia.

Validation of SARAL/AltiKa data in the Amazon basin

NASA Astrophysics Data System (ADS)

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

2015-04-01

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

Climatic and anthropogenic drivers of northern Amazon fires during the 2015-2016 El Niño event.

PubMed

Fonseca, Marisa G; Anderson, Liana O; Arai, Egidio; Shimabukuro, Yosio E; Xaud, Haron A M; Xaud, Maristela R; Madani, Nima; Wagner, Fabien H; Aragão, Luiz E O C

2017-12-01

The strong El Niño Southern Oscillation (ENSO) event that occurred in 2015-2016 caused extreme drought in the northern Brazilian Amazon, especially in the state of Roraima, increasing fire occurrence. Here we map the extent of precipitation and fire anomalies and quantify the effects of climatic and anthropogenic drivers on fire occurrence during the 2015-2016 dry season (from December 2015 to March 2016) in the state of Roraima. To achieve these objectives we first estimated the spatial pattern of precipitation anomalies, based on long-term data from the TRMM (Tropical Rainfall Measuring Mission), and the fire anomaly, based on MODIS (Moderate Resolution Imaging Spectroradiometer) active fire detections during the referred period. Then, we integrated climatic and anthropogenic drivers in a Maximum Entropy (MaxEnt) model to quantify fire probability, assessing (1) the model accuracy during the 2015-2016 and the 2016-2017 dry seasons; (2) the relative importance of each predictor variable on the model predictive performance; and (3) the response curves, showing how each environmental variable affects the fire probability. Approximately 59% (132,900 km 2 ) of the study area was exposed to precipitation anomalies ≤-1 standard deviation (SD) in January and ~48% (~106,800 km 2 ) in March. About 38% (86,200 km 2 ) of the study area experienced fire anomalies ≥1 SD in at least one month between December 2015 and March 2016. The distance to roads and the direct ENSO effect on fire occurrence were the two most influential variables on model predictive performance. Despite the improvement of governmental actions of fire prevention and firefighting in Roraima since the last intense ENSO event (1997-1998), we show that fire still gets out of control in the state during extreme drought events. Our results indicate that if no prevention actions are undertaken, future road network expansion and a climate-induced increase in water stress will amplify fire occurrence in the northern Amazon, even in its humid dense forests. As an additional outcome of our analysis, we conclude that the model and the data we used may help to guide on-the-ground fire-prevention actions and firefighting planning and therefore minimize fire-related ecosystems degradation, economic losses and carbon emissions in Roraima. © 2017 by the Ecological Society of America.

Shifts in the Budyko curve over the past decade in the Amazon basin

NASA Astrophysics Data System (ADS)

Maeda, E. E.; Ma, X.; Liu, Y.; Huete, A. R.

2017-12-01

The Amazon basin has experienced extensive forest loss during the past decades. These changes can exert significant impact on regional water and energy budget, as well as other environmental processes. Here we evaluated how forest loss in the Madeira and Tapajós River basins, between 2002 and 2015, affected the Budyko relationship. The Budyko framework describes the links between climate and hydrological components, where evapotranspiration (ET) is limited by the supply of either water or energy. The framework is composed by two components, the dryness index (DI) and the evaporative index (EI). The DI determines the type and degree of limitation, with values lower than 1 represent energy-limited condition and values higher than 1, water-limited. The EI describes the partitioning of rainfall (P) into ET and runoff (R), with higher values indicating a larger proportion of ET. In this study, we use a modified version of the Budyko framework, which accounts for intra-annual changes in water storage (dS). Hence, the effective rainfall is represented by P-dS, so that EI=ET/(P-dS) and the DI= PET/(P-dS). We show that the Madeira and Tapajós River basins have lost approximately 60000 km2 and 50000km2 of forested area by 2015, respectively. Our results indicate that these changes caused a subtle shift in the Budyko curve in both basins. At the Madeira basin, a reduction in the DI indicate a shift towards lower water limitation, while decreasing EI indicate that a higher proportion of P is being converted into runoff. At the Tapajós basin, we also observe an overall decrease in the DI, but no significant trends in the evaporative index was observed. We expect that the observed shifts provide a new insight on the Amazon forest responses to changes in climate and land use. Further studies will focus in identifying the biophysical mechanisms driving these shifts, as well as seasonal aspects of the changes.

Cloud Condensation Nuclei Activity of Aerosols during GoAmazon 2014/15 Field Campaign Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, J.; Martin, S. T.; Kleinman, L.

2016-03-01

Aerosol indirect effects, which represent the impact of aerosols on climate through influencing the properties of clouds, remain one of the main uncertainties in climate predictions (Stocker et al. 2013). Reducing this large uncertainty requires both improved understanding and representation of aerosol properties and processes in climate models, including the cloud activation properties of aerosols. The Atmospheric System Research (ASR) science program plan of January 2010 states that: “A key requirement for simulating aerosol-cloud interactions is the ability to calculate cloud condensation nuclei and ice nuclei (CCN and IN, respectively) concentrations as a function of supersaturation from the chemical andmore » microphysical properties of the aerosol.” The Observations and Modeling of the Green Ocean Amazon (GoAmazon 2014/15) study seeks to understand how aerosol and cloud life cycles are influenced by pollutant outflow from a tropical megacity (Manaus)—in particular, the differences in cloud-aerosol-precipitation interactions between polluted and pristine conditions. One key question of GoAmazon2014/5 is: “What is the influence of the Manaus pollution plume on the cloud condensation nuclei (CCN) activities of the aerosol particles and the secondary organic material in the particles?” To address this question, we measured size-resolved CCN spectra, a critical measurement for GoAmazon2014/5.« less

Hydroclimate changes across the Amazon lowlands over the past 45,000 years

NASA Astrophysics Data System (ADS)

Wang, Xianfeng; Edwards, R. Lawrence; Auler, Augusto S.; Cheng, Hai; Kong, Xinggong; Wang, Yongjin; Cruz, Francisco W.; Dorale, Jeffrey A.; Chiang, Hong-Wei

2017-01-01

Reconstructing the history of tropical hydroclimates has been difficult, particularly for the Amazon basin—one of Earth’s major centres of deep atmospheric convection. For example, whether the Amazon basin was substantially drier or remained wet during glacial times has been controversial, largely because most study sites have been located on the periphery of the basin, and because interpretations can be complicated by sediment preservation, uncertainties in chronology, and topographical setting. Here we show that rainfall in the basin responds closely to changes in glacial boundary conditions in terms of temperature and atmospheric concentrations of carbon dioxide. Our results are based on a decadally resolved, uranium/thorium-dated, oxygen isotopic record for much of the past 45,000 years, obtained using speleothems from Paraíso Cave in eastern Amazonia; we interpret the record as being broadly related to precipitation. Relative to modern levels, precipitation in the region was about 58% during the Last Glacial Maximum (around 21,000 years ago) and 142% during the mid-Holocene epoch (about 6,000 years ago). We find that, as compared with cave records from the western edge of the lowlands, the Amazon was widely drier during the last glacial period, with much less recycling of water and probably reduced plant transpiration, although the rainforest persisted throughout this time.

Hydroclimate changes across the Amazon lowlands over the past 45,000 years.

PubMed

Wang, Xianfeng; Edwards, R Lawrence; Auler, Augusto S; Cheng, Hai; Kong, Xinggong; Wang, Yongjin; Cruz, Francisco W; Dorale, Jeffrey A; Chiang, Hong-Wei

2017-01-11

Reconstructing the history of tropical hydroclimates has been difficult, particularly for the Amazon basin-one of Earth's major centres of deep atmospheric convection. For example, whether the Amazon basin was substantially drier or remained wet during glacial times has been controversial, largely because most study sites have been located on the periphery of the basin, and because interpretations can be complicated by sediment preservation, uncertainties in chronology, and topographical setting. Here we show that rainfall in the basin responds closely to changes in glacial boundary conditions in terms of temperature and atmospheric concentrations of carbon dioxide. Our results are based on a decadally resolved, uranium/thorium-dated, oxygen isotopic record for much of the past 45,000 years, obtained using speleothems from Paraíso Cave in eastern Amazonia; we interpret the record as being broadly related to precipitation. Relative to modern levels, precipitation in the region was about 58% during the Last Glacial Maximum (around 21,000 years ago) and 142% during the mid-Holocene epoch (about 6,000 years ago). We find that, as compared with cave records from the western edge of the lowlands, the Amazon was widely drier during the last glacial period, with much less recycling of water and probably reduced plant transpiration, although the rainforest persisted throughout this time.

CCN numerical simulations for the GoAmazon with the OLAM model

NASA Astrophysics Data System (ADS)

Ramos-da-Silva, R.; Haas, R.; Barbosa, H. M.; Machado, L.

2015-12-01

Manaus is a large city in the center of the Amazon rainforest. The GoAmazon field project is exploring the region through various data collection and modeling to investigate in impacts of the urban polluted plume on the surrounding pristine areas. In this study a numerical model was applied to simulate the atmospheric dynamics and the Cloud Condensation Nucleai (CCN) concentrations evolution. Simulations with and without the urban plume was performed to identify its dynamics and local impacts. The results show that the land surface characteristics has important hole on the CCN distribution and rainfall over the region. At the south of Manaus the atmospheric dynamics is dominated by the cloud streets that are aligned with the trade winds and the Amazon River. At the north of Manaus, the Negro River produces the advection of a more stable atmosphere causing a higher CCN concentration on the boundary layer. Assuming a local high CCN concentration at the Manaus boundary layer region, the simulations show that the land-atmosphere interaction sets important dynamics on the plume. The model shows that the CCN plume moves along with the flow towards southwest of Manaus following the cloud streets and the river direction having the highest concentrations over the most stable water surface regions.

Nitrogen management challenges in major watersheds of South America

NASA Astrophysics Data System (ADS)

Bustamante, Mercedes M. C.; Martinelli, Luiz Antonio; Pérez, Tibisay; Rasse, Rafael; Ometto, Jean Pierre H. B.; Siqueira Pacheco, Felipe; Rafaela Machado Lins, Silvia; Marquina, Sorena

2015-06-01

Urbanization and land use changes alter the nitrogen (N) cycle, with critical consequences for continental freshwater resources, coastal zones, and human health. Sewage and poor watershed management lead to impoverishment of inland water resources and degradation of coastal zones. Here we review the N contents of rivers of the three most important watersheds in South America: the Amazon, La Plata, and Orinoco basins. To evaluate potential impacts on coastal zones, we also present data on small- and medium-sized Venezuelan watersheds that drain into the Caribbean Sea and are impacted by anthropogenic activities. Median concentrations of total dissolved nitrogen (TDN) were 325 μg L-1 and 275 μg L-1 in the Amazon and Orinoco basins, respectively, increasing to nearly 850 μg L-1 in La Plata Basin rivers and 2000 μg L-1 in small northern Venezuelan watersheds. The median TDN yield of Amazon Basin rivers (approximately 4 kg ha-1 yr-1) was larger than TDN yields of undisturbed rivers of the La Plata and Orinoco basins; however, TDN yields of polluted rivers were much higher than those of the Amazon and Orinoco rivers. Organic matter loads from natural and anthropogenic sources in rivers of South America strongly influence the N dynamics of this region.

Multi-scale assessment of human-induced changes to ...

EPA Pesticide Factsheets

Context: Land use change and forest degradation have myriad effects on tropical ecosystems. Yet their consequences for low-order streams remain very poorly understood, including in the world´s largest freshwater basin, the Amazon.Objectives: Determine the degree to which physical and chemical characteristics of the instream habitat of low-order Amazonian streams change in response to past local- and catchment-level anthropogenic disturbances. Methods: To do so, we collected field instream habitat (i.e., physical habitat and water quality) and landscape data from 99 stream sites in two eastern Brazilian Amazon regions. We used random forest regression trees to assess the relative importance of different predictor variables in determining changes in instream habitat response variables. Adaptations the USEPA’s National Aquatic Resource Survey (NARS) designs, field methods, and approaches for assessing ecological condition have been applied in state and basin stream surveys throughout the U.S., and also in countries outside of the U.S. These applications not only provide valuable tests of the NARS approaches, but generate new understandings of natural and anthropogenic controls on biota and physical habitat in streams. Results from applications in Brazil, for example, not only aid interpretation of the condition of Brazilian streams, but also refine approaches for interpreting aquatic resource surveys in the U.S. and elsewhere. In this article, the authors des

Fine-Scale Relief in the Amazon Drives Large Scale Ecohydrological Processes

NASA Astrophysics Data System (ADS)

Nobre, A. D.; Cuartas, A.; Hodnett, M.; Saleska, S. R.

2014-12-01

Access to soil water by roots is a key ecophysiological factor for plant productivity in natural systems. Periodically during dry seasons or critically during episodic climate droughts, shortage of water supply can reduce or severely impair plant life. At the other extreme persistent soil waterlogging will limit root respiration and restrict local establishment to adapted species, usually leading to stunted and less productive communities. Soil-water availability is therefore a very important climate variable controlling plant physiology and ecosystem dynamics. Terra-firme, the non-seasonally floodable terrain that covers 82% of the landscape in Amazonia,[1] supports the most massive part of the rainforest ecosystem. The availability of soil water data for terra-firme is scant and very coarse. This lack of data has hampered observational and modeling studies aiming to develop a large-scale integrative ecohydrological picture of Amazonia and its vulnerability to climate change. We have mapped the Amazon basin with a new terrain model developed in our group (HAND, Height Above the Nearest drainage[2]), delineating soil water environments using topographical data from the SRTM digital elevation model (250 m horizontal interpolated resolution). The preliminary results show that more than 50% of Terra-firme has the water table very close to the surface (up to 2 m deep), while the remainder of the upland landscape has variable degree of dependence on non-saturated soil (vadose layer). The mapping also shows extremely heterogeneous patterns of fine-scale relief across the basin, which implies complex ecohydrological regional forcing on the forest physiology. Ecoclimate studies should therefore take into account fine-scale relief and its implications for soil-water availability to plant processes. [1] Melack, J. M., & Hess, L. L. (2011). Remote sensing of the distribution and extent of wetlands in the Amazon basin. In W. J. Junk & M. Piedade (Eds.), Amazonian floodplain forests: Ecophysiology, ecology, biodiversity and sustainable management (pp. 1-28). Ecological Studies-Springer. [2] Nobre, A. D., Cuartas, L. A., Hodnett, M., … Saleska, S. (2011). Height Above the Nearest Drainage - a hydrologically relevant new terrain model. Journal of Hydrology, 404(1-2), 13-29

Spatial and Temporal Variations in the Partial Pressure and Emission of CO2 and CH4 in and Amazon Floodplain Lake

NASA Astrophysics Data System (ADS)

Forsberg, B. R.; Amaral, J. H.; Barbosa, P.; Kasper, D.; MacIntyre, S.; Cortes, A.; Sarmento, H.; Borges, A. V.; Melack, J. M.; Farjalla, V.

2015-12-01

The Amazon floodplain contains a variety of wetland environments which contribute CO2 and CH4 to the regional and global atmospheres. The partial pressure and emission of these greenhouse gases (GHGs) varies: 1) between habitats, 2) seasonally, as the characteristics these habitats changes and 3) diurnally, in response to diurnal stratification. In this study, we investigated the combined influence of these factors on the partial pressure and emission of GHGs in Lago Janauacá, a central Amazon floodplain lake (3o23' S; 60o18' O). All measurements were made between August of 2014 and April of 2015 at two different sites and in three distinct habitats: open water, flooded forest, flooded macrophytes. Concentrations of CO2 and CH4 in air were measured continuously with a cavity enhanced absorption spectrometer, Los Gatos Research´s Ultraportable Greenhouse Gas Analyzer (UGGA). Vertical profiles o pCO2 and pCH4 were measured using the UGGA connected to an electric pump and equilibrator. Diffusive surface emissions were estimated with the UGGA connected to a static floating chamber. To investigate the influence of vertical stratification and mixing on GHG partial pressure and emissions, a meteorological station and submersible sensor chain were deployed at each site. Meteorological sensors included wind speed and direction. The submersible chains included thermistors and oxygen sensors. Depth profiles of partial pressure and diffusive emissions for both CO2 and CH4 varied diurnally, seasonally and between habitats. Both pCO2 and pCH4 were consistently higher in bottom than surface waters with the largest differences occurring at high water when thermal stratification was most stable. Methane emissions and partial pressures were highest at low water while pCO2 and CO2 fluxes were highest during high water periods, with 35% of CO2 fluxes at low water being negative. The highest average surface value of pCO2 (5491 μatm), encountered during rising water, was ~3 times higher than that encountered at low water (1708 μatm). Partial pressures and emissions of both CO2 and CH4 were greatest in open water habitats and consistently higher at night. These patterns reflected the higher levels of wind driven mixing and turbulence in open water environments and higher convective mixing at night which promoted diffusive emission.

Mercury concentrations in urine of amerindian populations near oil fields in the peruvian and ecuadorian amazon.

PubMed

Webb, Jena; Coomes, Oliver T; Ross, Nancy; Mergler, Donna

2016-11-01

Mercury is a global contaminant with toxic, persistent effects on human health. Petroleum extraction is an important source of elemental mercury; little is known about human exposure levels near oil fields in the Amazon basin. To characterize mercury levels in people living near oil production sites in the Peruvian and Ecuadorian Amazon, controlling for fish consumption, occupation, source of water and socio-demographic characteristics. Analyze mercury levels in urine samples using cold vapour atomic fluorescence spectrometry from 76 indigenous men and women in eight riverine communities situated near oil wells or pipelines. Subjects answered a questionnaire soliciting socio-demographic, occupational and dietary information. Data were analyzed using multiple linear regression modeling. The mean value of U-Hg was 2.61μg/g creatinine (95% CI: 2.14-3.08), with 7% of the sample recording values above the global background standard suggested by The World Health Organization (5μg/g creatinine). Women who used water from a surface source had two and a half times the amount of mercury in their urine (mean=3.70μg/g creatinine, 95% CI: 2.26-5.15) compared with women who used other water sources (mean =1.39μg/g creatinine, 95% CI: 0.51-2.25). Men who were involved in an oil clean-up operation had twice as much mercury in their urine (mean =3.07μg/g creatinine, 95% CI: 1.97-4.16) as did those who worked on other tasks (mean =1.56μg/g creatinine, 95% CI: 1.48-2.65). Mercury levels were not associated with the number of fish meals per week. Indigenous peoples of the Peruvian and Ecuadorian Amazon living near oil production sites generally had urine mercury levels within the global background standard suggested by the World Health Organization. Increased levels of mercury in urine were detected for men involved in oil spill remediation and for women who relied on surface water for household needs. These findings signal the need for strict safety measures to limit the amount of oil entering the waterways in Andean Amazonia so as to protect the health of indigenous people. Copyright © 2016 Elsevier Inc. All rights reserved.

A Regional-Scale Assessment of Satellite Derived Precipitable Water Vapor Across The Amazon Basin

NASA Technical Reports Server (NTRS)

DeLiberty, Tracy; Callahan, John; Guillory, Anthony R.; Jedlovec, Gary

2000-01-01

Atmospheric water vapor is widely recognized as a key climate variable, linking an assortment of poorly understood and complex processes. It is a major element of the hydrological cycle and provides a mechanism for energy exchange among many of the Earth system components. Reducing uncertainty in our current knowledge of water vapor and its role in the climate system requires accurate measurement, improved modeling techniques, and long-term prediction. Satellites have the potential to satisfy these criteria, as well as provide high resolution measurements that are not available from conventional sources. The focus of this paper is to examine the temporal and mesoscale variations of satellite derived precipitable water vapor (PW) across the Amazon Basin. This region is pivotal in the functioning of the global climate system through its abundant release of latent heat associated with heavy precipitation events. In addition, anthropogenic deforestation and biomass burning activities in recent decades are altering the conditions of the atmosphere, especially in the planetary boundary layer. A physical split-window (PSW) algorithm estimates PW using images from the GOES satellites along with the NCEP/NCAR Reanalysis data that provides the first guess information. Retrievals are made at a three-hourly time step during daylight hours in the Amazon Basin and surrounding areas for the months of June and October in 1988 (dry year) and 1995 (wet year). Spatially continuous fields are generated 5 times daily at 12Z, 15Z, 18Z, 21Z, and 00Z. These fields are then averaged to create monthly and 3 hourly monthly grids. Overall, the PSW estimates PW reasonable well in the Amazon with MAE ranging from 3.0 - 9.0 mm and MAE/observed mean around 20% in comparison to radiosonde observations. The distribution of PW generally mimics that of precipitation. Maximum values (42 - 52 mm) are located in the Northwest whereas minimum values (18 - 27 mm) are found along Brazil's East coast. Aside from the East coast, PW has a stronger north-south gradient than that of rainfall. As for the temporal variation of PW, June (1988 and 1995) experiences a peak about 1400 local time, corresponding to a maximum in air temperature. In contrast, October (1988 and 1995) experiences a maximum early in the day, 1100 local time, with a gradual decrease toward nighttime.

The steady-state mosaic of disturbance and succession across an old-growth Central Amazon forest landscape.

PubMed

Chambers, Jeffrey Q; Negron-Juarez, Robinson I; Marra, Daniel Magnabosco; Di Vittorio, Alan; Tews, Joerg; Roberts, Dar; Ribeiro, Gabriel H P M; Trumbore, Susan E; Higuchi, Niro

2013-03-05

Old-growth forest ecosystems comprise a mosaic of patches in different successional stages, with the fraction of the landscape in any particular state relatively constant over large temporal and spatial scales. The size distribution and return frequency of disturbance events, and subsequent recovery processes, determine to a large extent the spatial scale over which this old-growth steady state develops. Here, we characterize this mosaic for a Central Amazon forest by integrating field plot data, remote sensing disturbance probability distribution functions, and individual-based simulation modeling. Results demonstrate that a steady state of patches of varying successional age occurs over a relatively large spatial scale, with important implications for detecting temporal trends on plots that sample a small fraction of the landscape. Long highly significant stochastic runs averaging 1.0 Mg biomass⋅ha(-1)⋅y(-1) were often punctuated by episodic disturbance events, resulting in a sawtooth time series of hectare-scale tree biomass. To maximize the detection of temporal trends for this Central Amazon site (e.g., driven by CO2 fertilization), plots larger than 10 ha would provide the greatest sensitivity. A model-based analysis of fractional mortality across all gap sizes demonstrated that 9.1-16.9% of tree mortality was missing from plot-based approaches, underscoring the need to combine plot and remote-sensing methods for estimating net landscape carbon balance. Old-growth tropical forests can exhibit complex large-scale structure driven by disturbance and recovery cycles, with ecosystem and community attributes of hectare-scale plots exhibiting continuous dynamic departures from a steady-state condition.

War and Peace in the Amazon: Strategic Implications for the United States and Latin America of the 1995 Ecuador-Peru War.

DTIC Science & Technology

1995-11-24

Agreement and Security," El Comercio (Lima), March 22, 1995, p. A2, as reported in FBIS-LA, April 3, 1995. 19. "Amnesty Law Criticized, Creation of Truth...of National Security and Strategy November 24, 1995 ******* An earlier version of this paper, to be published in the fall 1995 edition of SER en el ...had adjudicated the demarcation of the boundary between Honduras and El Salvador. Because of these considerations, the war in the Amazon headwaters

Source area and seasonal variation of dissolved Sr isotope composition in rivers of the Amazon basin

NASA Astrophysics Data System (ADS)

Santos, Roberto V.; Sondag, Francis; Cochonneau, Gerard; Lagane, Christelle; Brunet, Pierre; Hattingh, Karina; Chaves, Jeane G. S.

2014-05-01

We present dissolved Sr isotope data collected over 8 years from three main river systems from the Amazon Basin: Beni-Madeira, Solimões, Amazon, and Negro. The data show large 87Sr/86Sr ratio variations that were correlated with the water discharge and geology of the source areas of the suspended sediments. The Beni-Madeira system displays a high average 87Sr/86Sr ratio and large 87Sr/86Sr fluctuations during the hydrological cycle. This large average value and fluctuations were related to the presence of Precambrian rocks and Ordovician sediments in the source area of the suspended sediment of the river. In contrast, the Solimões system displays a narrow range of Sr isotope ratio variations and an average value close to 0.709. This river drains mostly Phanerozoic rocks of northern Peru and Ecuador that are characterized by low Sr isotope ratios. Despite draining areas underlain by Precambrian rocks and having high 87Sr/86Sr ratios, such rivers as the Negro and Tapajós play a minor role in the total Sr budget of the Amazon Basin. The isotopic fluctuations in the Beni-Madeira River were observed to propagate downstream at least as far as Óbidos, in the Amazon River. This signal is characterized by an inverse relationship between the concentration of elemental Sr and its isotopic ratios. During the raining season there is an increase in Sr isotopic ratio accompanied by a decrease in elemental Sr concentration. During the dry season, the Sr isotopic ration decreases and the elemental Sr concentration increases.

Genetic structure and historical diversification of catfish Brachyplatystoma platynemum (Siluriformes: Pimelodidae) in the Amazon basin with implications for its conservation.

PubMed

Ochoa, Luz Eneida; Pereira, Luiz Henrique G; Costa-Silva, Guilherme Jose; Roxo, Fábio F; Batista, Jacqueline S; Formiga, Kyara; Foresti, Fausto; Oliveira, Claudio

2015-05-01

Brachyplatystoma platynemum is a catfish species widely distributed in the Amazon basin. Despite being considered of little commercial interest, the decline in other fish populations has contributed to the increase in the catches of this species. The structure, population genetic variability, and evolutionary process that have driven the diversification of this species are presently unknown. Considering that, in order to better understand the genetic structure of this species, we analyzed individuals from seven locations of the Amazon basin using eight molecular markers: control region and cytochrome b mtDNA sequences, and a set of six nuclear microsatellite loci. The results show high levels of haplotype diversity and point to the occurrence of two structured populations (Amazon River and the Madeira River) with high values for F ST. Divergence time estimates based on mtDNA indicated that these populations diverged about 1.0 Mya (0.2-2.5 Mya 95% HPD) using cytochrome b and 1.4 Mya (0.2-2.7 Mya 95% HPD) using control region. During that time, the influence of climate changes and hydrological events such as sea level oscillations and drainage isolation as a result of geological processes in the Pleistocene may have contributed to the current structure of B. platynemum populations, as well as of differences in water chemistry in Madeira River. The strong genetic structure and the time of genetic divergence estimated for the groups may indicate the existence of strong structure populations of B. platynemum in the Amazon basin.

Amazon forests did not green up during the 2005 drought

NASA Astrophysics Data System (ADS)

Samanta, A.; Ganguly, S.; Hashimoto, H.; Devadiga, S.; Vermote, E. F.; Knyazikhin, Y.; Nemani, R. R.; Myneni, R. B.

2009-12-01

The sensitivity of Amazon rainforests to dry-season droughts remains unresolved with reports of enhanced tree mortality and forest fires, on one hand, and, excessive forest green-up, on the other. Here using the latest and improved version of satellite-derived vegetation greenness data - Collection 5 (C5) Enhanced Vegetation Index (EVI) - we report that the there is no evidence of large-scale greening of the Amazon during the 2005 drought - approximately 11%-12% of these forests display greening, while, 28%-29% show browning or no-change, and for the rest the data are not of sufficient quality to characterize any changes. In addition, independent satellite-derived data on precipitation, surface radiation and aerosols do not substantiate underlying assumptions of the hypothesis of enhanced photosynthetic capacity of intact Amazon forests stimulated by increased light availability during a drought. First, interannual changes in dry-season greenness are unrelated to concurrent changes in light availability. Second, the 2005 drought cannot be used as a surrogate for light availability to these rainforests owing to persistently high aerosol loads in the atmosphere. Third, the spatial extent and magnitude of greening do not change systematically with drought severity. Finally, the changes in vegetation activity of these forests during the drought-stricken dry season of 2005 are not unique in comparison to that observed during dry seasons of non-drought years. Our analysis also demonstrates the critical role of biomass burning aerosols in limiting light availability to water stressed Amazon forests during the dry season of 2005. This will have important implications for the sensitivity of these forests to similar droughts in future.

GoAmazon 2014/15 Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS) Field Campaign Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, JN

2016-04-01

The Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS) deployment to the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility T3 site in Manacapuru, Brazil, was motivated by two main scientific objectives of the Green Ocean Amazon (GoAmazon) 2014/15 field campaign. 1) Study the interactions between anthropogenic and biogenic emissions by determining important molecular species in ambient nanoparticles. To address this, TDCIMS data will be combined with coincident measurements such as gas-phase sulfuric acid to determine the contribution of sulfuric acid condensation to nucleation and growth. We can then compare that result to TDCIMS-derived nanoparticle composition tomore » determine the fraction of growth that can be attributed to the uptake of organic compounds. The molecular composition of sampled particles will also be used to attribute specific chemical species and mechanisms to growth, such as the condensation of low-volatility species or the oligomerization of α-dicarbonyl compounds. 2) Determine the source of new ambient nanoparticles in the Amazon. The hypothesis prior to measurements was that potassium salts formed from the evaporation of primary particles emitted by fungal spores can provide a unique and important pathway for new particle production in the Amazon basin. To explore this hypothesis, the TDCIMS recorded the mass spectra of sampled ambient particles using a protonated water cluster Chemical Ionization Mass Spectrometer (CIMS). Laboratory tests performed using potassium salts show that the TDCIMS can detect potassium with high sensitivity with this technique.« less

Genetic structure and historical diversification of catfish Brachyplatystoma platynemum (Siluriformes: Pimelodidae) in the Amazon basin with implications for its conservation

PubMed Central

Ochoa, Luz Eneida; Pereira, Luiz Henrique G; Costa-Silva, Guilherme Jose; Roxo, Fábio F; Batista, Jacqueline S; Formiga, Kyara; Foresti, Fausto; Oliveira, Claudio

2015-01-01

Brachyplatystoma platynemum is a catfish species widely distributed in the Amazon basin. Despite being considered of little commercial interest, the decline in other fish populations has contributed to the increase in the catches of this species. The structure, population genetic variability, and evolutionary process that have driven the diversification of this species are presently unknown. Considering that, in order to better understand the genetic structure of this species, we analyzed individuals from seven locations of the Amazon basin using eight molecular markers: control region and cytochrome b mtDNA sequences, and a set of six nuclear microsatellite loci. The results show high levels of haplotype diversity and point to the occurrence of two structured populations (Amazon River and the Madeira River) with high values for FST. Divergence time estimates based on mtDNA indicated that these populations diverged about 1.0 Mya (0.2–2.5 Mya 95% HPD) using cytochrome b and 1.4 Mya (0.2–2.7 Mya 95% HPD) using control region. During that time, the influence of climate changes and hydrological events such as sea level oscillations and drainage isolation as a result of geological processes in the Pleistocene may have contributed to the current structure of B. platynemum populations, as well as of differences in water chemistry in Madeira River. The strong genetic structure and the time of genetic divergence estimated for the groups may indicate the existence of strong structure populations of B. platynemum in the Amazon basin. PMID:26045952

Trypanosoma cruzi IV Causing Outbreaks of Acute Chagas Disease and Infections by Different Haplotypes in the Western Brazilian Amazonia

PubMed Central

Monteiro, Wuelton Marcelo; Magalhães, Laylah Kelre Costa; de Sá, Amanda Regina Nichi; Gomes, Mônica Lúcia; Toledo, Max Jean de Ornelas; Borges, Lara; Pires, Isa; de Oliveira Guerra, Jorge Augusto; Silveira, Henrique; Barbosa, Maria das Graças Vale

2012-01-01

Background Chagas disease is an emergent tropical disease in the Brazilian Amazon Region, with an increasing number of cases in recent decades. In this region, the sylvatic cycle of Trypanosoma cruzi transmission, which constitutes a reservoir of parasites that might be associated with specific molecular, epidemiological and clinical traits, has been little explored. The objective of this work is to genetically characterize stocks of T. cruzi from human cases, triatomines and reservoir mammals in the State of Amazonas, in the Western Brazilian Amazon. Methodology/Principal Findings We analyzed 96 T. cruzi samples from four municipalities in distant locations of the State of Amazonas. Molecular characterization of isolated parasites from cultures in LIT medium or directly from vectors or whole human blood was performed by PCR of the non-transcribed spacer of the mini-exon and of the 24 S alfa ribosomal RNA gene, RFLP and sequencing of the mitochondrial cytochrome c oxidase subunit II (COII) gene, and by sequencing of the glucose-phosphate isomerase gene. The T. cruzi parasites from two outbreaks of acute disease were all typed as TcIV. One of the outbreaks was triggered by several haplotypes of the same DTU. TcIV also occurred in isolated cases and in Rhodnius robustus. Incongruence between mitochondrial and nuclear phylogenies is likely to be indicative of historical genetic exchange events resulting in mitochondrial introgression between TcIII and TcIV DTUs from Western Brazilian Amazon. TcI predominated among triatomines and was the unique DTU infecting marsupials. Conclusion/Significance DTU TcIV, rarely associated with human Chagas disease in other areas of the Amazon basin, is the major strain responsible for the human infections in the Western Brazilian Amazon, occurring in outbreaks as single or mixed infections by different haplotypes. PMID:22848457

Diverse Early Life-History Strategies in Migratory Amazonian Catfish: Implications for Conservation and Management

PubMed Central

Hegg, Jens C.; Giarrizzo, Tommaso; Kennedy, Brian P.

2015-01-01

Animal migrations provide important ecological functions and can allow for increased biodiversity through habitat and niche diversification. However, aquatic migrations in general, and those of the world’s largest fish in particular, are imperiled worldwide and are often poorly understood. Several species of large Amazonian catfish carry out some of the longest freshwater fish migrations in the world, travelling from the Amazon River estuary to the Andes foothills. These species are important apex predators in the main stem rivers of the Amazon Basin and make up the region’s largest fishery. They are also the only species to utilize the entire Amazon Basin to complete their life cycle. Studies indicate both that the fisheries may be declining due to overfishing, and that the proposed and completed dams in their upstream range threaten spawning migrations. Despite this, surprisingly little is known about the details of these species’ migrations, or their life history. Otolith microchemistry has been an effective method for quantifying and reconstructing fish migrations worldwide across multiple spatial scales and may provide a powerful tool to understand the movements of Amazonian migratory catfish. Our objective was to describe the migratory behaviors of the three most populous and commercially important migratory catfish species, Dourada (Brachyplatystoma rousseauxii), Piramutaba (Brachyplatystoma vaillantii), and Piraíba (Brachyplatystoma filamentosum). We collected fish from the mouth of the Amazon River and the Central Amazon and used strontium isotope signatures (87Sr/86Sr) recorded in their otoliths to determine the location of early rearing and subsequent. Fish location was determined through discriminant function classification, using water chemistry data from the literature as a training set. Where water chemistry data was unavailable, we successfully in predicted 87Sr/86Sr isotope values using a regression-based approach that related the geology of the upstream watershed to the Sr isotope ratio. Our results provide the first reported otolith microchemical reconstruction of Brachyplatystoma migratory movements in the Amazon Basin. Our results indicate that juveniles exhibit diverse rearing strategies, rearing in both upstream and estuary environments. This contrasts with the prevailing understanding that juveniles rear in the estuary before migrating upstream; however, it is supported by some fisheries data that has indicated the presence of alternate spawning and rearing life-histories. The presence of alternate juvenile rearing strategies may have important implications for conservation and management of the fisheries in the region. PMID:26153984

Sea surface salinity fronts in the Tropical Atlantic Ocean

NASA Astrophysics Data System (ADS)

Ruiz-Etcheverry, L.; Maximenko, N. A.; Melnichenko, O.

2016-12-01

Marine fronts are narrow boundaries that separate water masses of different properties. These fronts are caused by various forcing and believed to be an important component of the coupled ocean-atmosphere system, particularly in the tropical oceans. In this study, we use sea surface salinity (SSS) observations from Aquarius satellite to investigate the spatial structure and temporal variability of SSS fronts in the tropical Atlantic. A number of frontal features have been identified. The mean magnitude of the SSS gradient is maximum near the mouth of the Congo River (0.3-0.4 psu/100km). Relative maxima are also observed in the Inter Tropical Convergence Zone (ITCZ), the Gulf of Guinea, and the mouth of the Amazon River. The pattern of the magnitude of the SSS anomaly gradient revealed that the interaction between river plumes and saltier interior water is complex and highly variable during the three-year observation period. The variability of the magnitude of the density anomaly gradient computed from Aquarius SSS and Reynolds SST is also discussed. Images of the ocean color are utilized to trace the movement of the Congo and Amazon River plumes and compare them with the magnitude of the SSS gradient. Additionally, we analyze de circulation associated with the Amazon plume with altimetry data, and the vertical structure and its changes in time through Argo profiles.

Groundwater and Terrestrial Water Storage

NASA Technical Reports Server (NTRS)

Rodell, Matthew; Chambers, Don P.; Famiglietti, James S.

2011-01-01

Most people think of groundwater as a resource, but it is also a useful indicator of climate variability and human impacts on the environment. Groundwater storage varies slowly relative to other non-frozen components of the water cycle, encapsulating long period variations and trends in surface meteorology. On seasonal to interannual timescales, groundwater is as dynamic as soil moisture, and it has been shown that groundwater storage changes have contributed to sea level variations. Groundwater monitoring well measurements are too sporadic and poorly assembled outside of the United States and a few other nations to permit direct global assessment of groundwater variability. However, observational estimates of terrestrial water storage (TWS) variations from the GRACE satellites largely represent groundwater storage variations on an interannual basis, save for high latitude/altitude (dominated by snow and ice) and wet tropical (surface water) regions. A figure maps changes in mean annual TWS from 2009 to 2010, based on GRACE, reflecting hydroclimatic conditions in 2010. Severe droughts impacted Russia and the Amazon, and drier than normal weather also affected the Indochinese peninsula, parts of central and southern Africa, and western Australia. Groundwater depletion continued in northern India, while heavy rains in California helped to replenish aquifers that have been depleted by drought and withdrawals for irrigation, though they are still below normal levels. Droughts in northern Argentina and western China similarly abated. Wet weather raised aquifer levels broadly across western Europe. Rains in eastern Australia caused flooding to the north and helped to mitigate a decade long drought in the south. Significant reductions in TWS seen in the coast of Alaska and the Patagonian Andes represent ongoing glacier melt, not groundwater depletion. Figures plot time series of zonal mean and global GRACE derived non-seasonal TWS anomalies (deviation from the mean of each month of the year) excluding Greenland and Antarctica. The two figures show that 2010 was the driest year since 2003. The drought in the Amazon was largely responsible, but an excess of water in 2009 seems to have buffered that drought to some extent. The drying trend in the 25-55 deg S zone is a combination of Patagonian glacier melt and drought in parts of Australia.

Stable carbon isotope cycling in mobile coastal muds of Amapá, Brazil

NASA Astrophysics Data System (ADS)

Zhu, Zhongbin; Aller, Robert C.; Mak, John

2002-10-01

Approximately 10% of the sediment delivered by the Amazon River moves northwest along the coast of Amapá, Brazil, initiating the Guianas mobile mud belt. Amapá coastal muds generally have a two-layer transport structure and are characterized by highly non-steady-state sedimentation. Isotopic compositions of pore water ∑CO 2 and solid phase C org demonstrate that remineralization in the surficial mobile zone (˜0.3-1 m thick) is dominated by terrestrial sources at sites in proximity to the mangrove fringe (˜1-2 m water depth), and marine (plus possible carbonate dissolution) sources further offshore (˜21 km, ˜7 m depth). The net δ13C of ∑CO 2 produced and C org remineralized is ˜-26‰ and -25.9‰, respectively inshore, and ˜-14‰ and -18.6‰, respectively offshore (compared to average terrestrial and marine C org end members of -28‰ and -20‰). Efficient remineralization in the suboxic mobile zone lowers particle surface loading of C org from ˜0.35 mg C m -2 in the Amazon delta topset to ˜0.13-0.16 along Amapá. Sequential, temperature-dependent extractions were used to operationally fractionate inorganic C pools. Authigenic carbonates, mostly siderite and mixed Ca, Mg, Fe, Mn-carbonates, dominate sediment inorganic C (˜50-200 μmol g -1). The mass weighted δ13C of carbonates, ˜-15‰ to -19‰, is relatively restricted in range compared to pore water ∑CO 2, implying most precipitation in the reactive mobile surface sediments. Periodic mixing with bottom seawater and/or dissolution of biogenic carbonates in the surficial layer shift δ13C values of pore water to heavier values than C org reactant sources. At one offshore site (˜7 m), about 22% of pore water ∑CO 2 has undergone reduction during methanogenesis below the mobile surface zone, extracting ∑CO 2 with δ13C˜-90‰ and leaving a residual δ13C˜-0.37‰. Diagenetic processes in the suboxic mobile mud zone dominate C remineralization and storage along the coast of Amapá.

The Green Ocean Amazon Experiment (GoAmazon2014/5) Observes Pollution Affecting Gases, Aerosols, Clouds, and Rainfall over the Rain Forest

DOE PAGES

Martin, S. T.; Artaxo, P.; Machado, L.; ...

2017-05-15

The Observations and Modeling of the Green Ocean Amazon 2014–2015 (GoAmazon2014/5) experiment took place around the urban region of Manaus in central Amazonia across 2 years. The urban pollution plume was used to study the susceptibility of gases, aerosols, clouds, and rainfall to human activities in a tropical environment. Many aspects of air quality, weather, terrestrial ecosystems, and climate work differently in the tropics than in the more thoroughly studied temperate regions of Earth. GoAmazon2014/5, a cooperative project of Brazil, Germany, and the United States, employed an unparalleled suite of measurements at nine ground sites and on board two aircraftmore » to investigate the flow of background air into Manaus, the emissions into the air over the city, and the advection of the pollution downwind of the city. Here in this paper, to visualize this train of processes and its effects, observations aboard a low-flying aircraft are presented. Comparative measurements within and adjacent to the plume followed the emissions of biogenic volatile organic carbon compounds (BVOCs) from the tropical forest, their transformations by the atmospheric oxidant cycle, alterations of this cycle by the influence of the pollutants, transformations of the chemical products into aerosol particles, the relationship of these particles to cloud condensation nuclei (CCN) activity, and the differences in cloud properties and rainfall for background compared to polluted conditions. The observations of the GoAmazon2014/5 experiment illustrate how the hydrologic cycle, radiation balance, and carbon recycling may be affected by present-day as well as future economic development and pollution over the Amazonian tropical forest.« less

The Green Ocean Amazon Experiment (GoAmazon2014/5) Observes Pollution Affecting Gases, Aerosols, Clouds, and Rainfall over the Rain Forest

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, S. T.; Artaxo, P.; Machado, L.

The Observations and Modeling of the Green Ocean Amazon 2014–2015 (GoAmazon2014/5) experiment took place around the urban region of Manaus in central Amazonia across 2 years. The urban pollution plume was used to study the susceptibility of gases, aerosols, clouds, and rainfall to human activities in a tropical environment. Many aspects of air quality, weather, terrestrial ecosystems, and climate work differently in the tropics than in the more thoroughly studied temperate regions of Earth. GoAmazon2014/5, a cooperative project of Brazil, Germany, and the United States, employed an unparalleled suite of measurements at nine ground sites and on board two aircraftmore » to investigate the flow of background air into Manaus, the emissions into the air over the city, and the advection of the pollution downwind of the city. Here in this paper, to visualize this train of processes and its effects, observations aboard a low-flying aircraft are presented. Comparative measurements within and adjacent to the plume followed the emissions of biogenic volatile organic carbon compounds (BVOCs) from the tropical forest, their transformations by the atmospheric oxidant cycle, alterations of this cycle by the influence of the pollutants, transformations of the chemical products into aerosol particles, the relationship of these particles to cloud condensation nuclei (CCN) activity, and the differences in cloud properties and rainfall for background compared to polluted conditions. The observations of the GoAmazon2014/5 experiment illustrate how the hydrologic cycle, radiation balance, and carbon recycling may be affected by present-day as well as future economic development and pollution over the Amazonian tropical forest.« less

Methods for in situ Mesocosm Water Table Manipulation in Amazon Peatlands

NASA Astrophysics Data System (ADS)

Sarno, B. G.; Guardia, J. R.; Torres, M. G.; Lopez, J. G.; Rios, M. L.; Saquiray, L. M.; Rodriguez, T. C.; Rivera, P. V.; Van Haren, J. L. M.; Cadillo-Quiroz, H.

2016-12-01

Rainfall manipulation in tropical Amazon rainforests has previously been used to analyze the effects of rapidly changing drought and flood seasons on canopy dynamics, above-ground ecological function and greenhouse gas cycles. We chose to focus on variance below the rootline due to the greater carbon mass and impact of this region and the variables affecting it. We designed and implemented a system that manipulates above and below ground water exposure to control soil saturation. Isolation of soil sample was collected using a PVC pipe submerged 50 cm into the ground with an overhead watershed and an underground water filter. Similarly, a control sample of the above ground water was collected. Above ground water control was performed, not unlike previous systems, using overhead cover, drainage and rerouting, constructed using 1 inch PVC sections configured to allow 25% shed, 50% shed, and 75% increase. Underground filters were designed using variable clay concentrations to achieve desired permeability and flow rate. We selected kiln-fire pure clay discs, instead of poly-acrylamide discs, to enable a steady flow of 0.83 mL/hr. In addition, we adjusted the concentration of the clay disc with sand buffering and carbon lacing at different mass concentrations to allow direct controls of the flow rate, as high as 12.45 mL/hr. Using pure clay concentrations of 100%, 75%, and 50% by mass, and lacing the filters with carbon fill of 10%, 20%, and 30% by volume, before kiln firing, allows much more desirable flow rates. These significant increases in flow rate allow for better control of both above and below ground water exposure. Such a system will enable a more complete geochemical and microbiological analysis of soil and water within this highly variable region of the rain forest. Construction and installation of the submerged towers has been performed at numerous sites along the Peruvian Amazon River basin. Monitoring soil respiration will be performed on the current installations on a continuous schedule for 6 months, in efforts to understand the effects of water table control on the microbial community respiration and greenhouse gases production in the tropical rainforest peatlands. Our work will allow for a more complete understanding of variation in greenhouse gas sources and the ecological carbon cycle due to water table change.

Prospects for land-use sustainability on the agricultural frontier of the Brazilian Amazon.

PubMed

Galford, Gillian L; Soares-Filho, Britaldo; Cerri, Carlos E P

2013-06-05

The Brazilian Amazon frontier shows how remarkable leadership can work towards increased agricultural productivity and environmental sustainability without new greenhouse gas emissions. This is due to initiatives among various stakeholders, including national and state government and agents, farmers, consumers, funding agencies and non-governmental organizations. Change has come both from bottom-up and top-down actions of these stakeholders, providing leadership, financing and monitoring to foster environmental sustainability and agricultural growth. Goals to reduce greenhouse gas emissions from land-cover and land-use change in Brazil are being achieved through a multi-tiered approach that includes policies to reduce deforestation and initiatives for forest restoration, as well as increased and diversified agricultural production, intensified ranching and innovations in agricultural management. Here, we address opportunities for the Brazilian Amazon in working towards low-carbon rural development and environmentally sustainable landscapes.

Prospects for land-use sustainability on the agricultural frontier of the Brazilian Amazon

PubMed Central

Galford, Gillian L.; Soares-Filho, Britaldo; Cerri, Carlos E. P.

2013-01-01

The Brazilian Amazon frontier shows how remarkable leadership can work towards increased agricultural productivity and environmental sustainability without new greenhouse gas emissions. This is due to initiatives among various stakeholders, including national and state government and agents, farmers, consumers, funding agencies and non-governmental organizations. Change has come both from bottom-up and top-down actions of these stakeholders, providing leadership, financing and monitoring to foster environmental sustainability and agricultural growth. Goals to reduce greenhouse gas emissions from land-cover and land-use change in Brazil are being achieved through a multi-tiered approach that includes policies to reduce deforestation and initiatives for forest restoration, as well as increased and diversified agricultural production, intensified ranching and innovations in agricultural management. Here, we address opportunities for the Brazilian Amazon in working towards low-carbon rural development and environmentally sustainable landscapes. PMID:23610175

The Duffy binding protein as a key target for a Plasmodium vivax vaccine: lessons from the Brazilian Amazon.

PubMed

Sousa, Taís Nóbrega de; Kano, Flora Satiko; Brito, Cristiana Ferreira Alves de; Carvalho, Luzia Helena

2014-05-23

Plasmodium vivax infects human erythrocytes through a major pathway that requires interaction between an apical parasite protein, the Duffy binding protein (PvDBP) and its receptor on reticulocytes, the Duffy antigen/receptor for chemokines (DARC). The importance of the interaction between PvDBP (region II, DBPII) and DARC to P. vivax infection has motivated our malaria research group at Oswaldo Cruz Foundation (state of Minas Gerais, Brazil) to conduct a number of immunoepidemiological studies to characterise the naturally acquired immunity to PvDBP in populations living in the Amazon rainforest. In this review, we provide an update on the immunology and molecular epidemiology of PvDBP in the Brazilian Amazon - an area of markedly unstable malaria transmission - and compare it with data from other parts of Latin America, as well as Asia and Oceania.

The Duffy binding protein as a key target for a Plasmodium vivax vaccine: lessons from the Brazilian Amazon.

PubMed

de Sousa, Taís Nóbrega; Kano, Flora Satiko; de Brito, Cristiana Ferreira Alves; Carvalho, Luzia Helena

2014-08-01

Plasmodium vivax infects human erythrocytes through a major pathway that requires interaction between an apical parasite protein, the Duffy binding protein (PvDBP) and its receptor on reticulocytes, the Duffy antigen/receptor for chemokines (DARC). The importance of the interaction between PvDBP (region II, DBPII) and DARC to P. vivax infection has motivated our malaria research group at Oswaldo Cruz Foundation (state of Minas Gerais, Brazil) to conduct a number of immunoepidemiological studies to characterise the naturally acquired immunity to PvDBP in populations living in the Amazon rainforest. In this review, we provide an update on the immunology and molecular epidemiology of PvDBP in the Brazilian Amazon - an area of markedly unstable malaria transmission - and compare it with data from other parts of Latin America, as well as Asia and Oceania.

Remote tropical and sub-tropical responses to Amazon deforestation

NASA Astrophysics Data System (ADS)

Badger, Andrew M.; Dirmeyer, Paul A.

2016-05-01

Replacing natural vegetation with realistic tropical crops over the Amazon region in a global Earth system model impacts vertical transport of heat and moisture, modifying the interaction between the atmospheric boundary layer and the free atmosphere. Vertical velocity is decreased over a majority of the Amazon region, shifting the ascending branch and modifying the seasonality of the Hadley circulation over the Atlantic and eastern Pacific oceans. Using a simple model that relates circulation changes to heating anomalies and generalizing the upper-atmosphere temperature response to deforestation, agreement is found between the response in the fully-coupled model and the simple solution. These changes to the large-scale dynamics significantly impact precipitation in several remote regions, namely sub-Saharan Africa, Mexico, the southwestern United States and extratropical South America, suggesting non-local climate repercussions for large-scale land use changes in the tropics are possible.

An inventory of coastal freshwater fishes from Amapá highlighting the occurrence of eight new records for Brazil

PubMed Central

Melo, Bruno F.; Benine, Ricardo C.; Britzke, Ricardo; Gama, Cecile S.; Oliveira, Claudio

2016-01-01

Abstract The Amazon Basin occupies a vast portion of northern South America and contains some of the highest species richness in the world. The northern Brazilian state of Amapá is delimited by the Amazonas River to the south, the Oyapock River to the northern boundary with French Guyana, and the Atlantic northeastern coast to Amazon estuary. Despite several expeditions to the Amazon in recent decades, little is known about the freshwater ichthyofauna from Amapá, with records limited to local inventories and species descriptions. This paper presents a compilation of the freshwater fish diversity sampled in fifteen sites covering two major Amapá ecoregions during the dry season of 2015. 120 species representing eight orders and 40 families are reported upon in this work. Eight species appear for the first time in the Brazilian territory providing new information for future conservation status evaluations. PMID:27551225

Regional atmospheric CO2 inversion reveals seasonal and geographic differences in Amazon net biome exchange.

PubMed

Alden, Caroline B; Miller, John B; Gatti, Luciana V; Gloor, Manuel M; Guan, Kaiyu; Michalak, Anna M; van der Laan-Luijkx, Ingrid T; Touma, Danielle; Andrews, Arlyn; Basso, Luana S; Correia, Caio S C; Domingues, Lucas G; Joiner, Joanna; Krol, Maarten C; Lyapustin, Alexei I; Peters, Wouter; Shiga, Yoichi P; Thoning, Kirk; van der Velde, Ivar R; van Leeuwen, Thijs T; Yadav, Vineet; Diffenbaugh, Noah S

2016-10-01

Understanding tropical rainforest carbon exchange and its response to heat and drought is critical for quantifying the effects of climate change on tropical ecosystems, including global climate-carbon feedbacks. Of particular importance for the global carbon budget is net biome exchange of CO2 with the atmosphere (NBE), which represents nonfire carbon fluxes into and out of biomass and soils. Subannual and sub-Basin Amazon NBE estimates have relied heavily on process-based biosphere models, despite lack of model agreement with plot-scale observations. We present a new analysis of airborne measurements that reveals monthly, regional-scale (~1-8 × 10(6)  km(2) ) NBE variations. We develop a regional atmospheric CO2 inversion that provides the first analysis of geographic and temporal variability in Amazon biosphere-atmosphere carbon exchange and that is minimally influenced by biosphere model-based first guesses of seasonal and annual mean fluxes. We find little evidence for a clear seasonal cycle in Amazon NBE but do find NBE sensitivity to aberrations from long-term mean climate. In particular, we observe increased NBE (more carbon emitted to the atmosphere) associated with heat and drought in 2010, and correlations between wet season NBE and precipitation (negative correlation) and temperature (positive correlation). In the eastern Amazon, pulses of increased NBE persisted through 2011, suggesting legacy effects of 2010 heat and drought. We also identify regional differences in postdrought NBE that appear related to long-term water availability. We examine satellite proxies and find evidence for higher gross primary productivity (GPP) during a pulse of increased carbon uptake in 2011, and lower GPP during a period of increased NBE in the 2010 dry season drought, but links between GPP and NBE changes are not conclusive. These results provide novel evidence of NBE sensitivity to short-term temperature and moisture extremes in the Amazon, where monthly and sub-Basin estimates have not been previously available. © 2016 John Wiley & Sons Ltd.

Regional Atmospheric CO2 Inversion Reveals Seasonal and Geographic Differences in Amazon Net Biome Exchange

NASA Technical Reports Server (NTRS)

Alden, Caroline B.; Miller, John B.; Gatti, Luciana V.; Gloor, Manuel M.; Guan, Kaiyu; Michalak, Anna M.; van der Laan-Luijkx, Ingrid; Touma, Danielle; Andrews, Arlyn; Basso, Luana G.;

Mercury concentrations in urine of amerindian populations near oil fields in the peruvian and ecuadorian amazon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Webb, Jena, E-mail: jena.webb@mail.mcgill.ca

Background: Mercury is a global contaminant with toxic, persistent effects on human health. Petroleum extraction is an important source of elemental mercury; little is known about human exposure levels near oil fields in the Amazon basin. Objectives: To characterize mercury levels in people living near oil production sites in the Peruvian and Ecuadorian Amazon, controlling for fish consumption, occupation, source of water and socio-demographic characteristics. Methods: Analyze mercury levels in urine samples using cold vapour atomic fluorescence spectrometry from 76 indigenous men and women in eight riverine communities situated near oil wells or pipelines. Subjects answered a questionnaire soliciting socio-demographic,more » occupational and dietary information. Data were analyzed using multiple linear regression modeling. Results: The mean value of U-Hg was 2.61 μg/g creatinine (95% CI: 2.14–3.08), with 7% of the sample recording values above the global background standard suggested by The World Health Organization (5 μg/g creatinine). Women who used water from a surface source had two and a half times the amount of mercury in their urine (mean=3.70 μg/g creatinine, 95% CI: 2.26–5.15) compared with women who used other water sources (mean =1.39 μg/g creatinine, 95% CI: 0.51–2.25). Men who were involved in an oil clean-up operation had twice as much mercury in their urine (mean =3.07 μg/g creatinine, 95% CI: 1.97–4.16) as did those who worked on other tasks (mean =1.56 μg/g creatinine, 95% CI: 1.48–2.65). Mercury levels were not associated with the number of fish meals per week. Conclusions: Indigenous peoples of the Peruvian and Ecuadorian Amazon living near oil production sites generally had urine mercury levels within the global background standard suggested by the World Health Organization. Increased levels of mercury in urine were detected for men involved in oil spill remediation and for women who relied on surface water for household needs. These findings signal the need for strict safety measures to limit the amount of oil entering the waterways in Andean Amazonia so as to protect the health of indigenous people. - Highlights: • 7% of participants had levels of inorganic mercury at or exceeding levels suggested by WHO (5 μg/g creatinine). • U-Hg levels were 2.5 times higher among women using surface water than those who drew on water from a well, spring or rain. • Men who had worked cleaning up an oil spill had more than twice the amount of mercury in their urine as men who did not.« less

Effects of Natural and Experimental Drought on Growth and Water Use Efficiency in Amazon trees

NASA Astrophysics Data System (ADS)

Vadeboncoeur, M. A.; Brum, M., Jr.; Oliveira, R. S.; Moutinho, V. H. P.; Flores, C. F.; Llerena, C. A.; Palace, M. W.; Asbjornsen, H.

2016-12-01

Severe regional droughts in the Amazon basin, mostly associated with El Nino events, have attracted considerable attention over the past decade, especially with regard to their effects on tree mortality, vulnerability to fire, and changes in the terrestrial budgets of carbon, water, and energy. Understanding the complex responses of forest ecosystems to such droughts is key to predicting how these globally critical forest ecosystems will respond to a changing climate with higher temperatures and greater precipitation variability. Though tree rings are not formed by all tropical tree species, they offer a unique retrospective approach for investigating patterns of climatic responses in both carbon cycling (primary production inferred from diameter growth) and water cycling (water use efficiency calculated from stable C isotope ratios). We sampled increment cores from 40 tree species at the Tapajos National Forest in Brazil, as well as the Cocha Cashu Biological Station in Peru, for an isotopic dendrochronological investigation into the effects of past droughts on the growth and water-use efficiency of canopy and mid-story tree species. We found that many but not all trees responded to drought years with periods of reduced growth lasting 2-3 years. Forthcoming data on carbon isotope ratios will allow us to compare the sensitivity of species and sites in terms of water use under drought conditions.

The evolution of organic matter along the lower Amazon River continuum - Óbidos to the ocean

NASA Astrophysics Data System (ADS)

Ward, N. D.; Keil, R. G.; Medeiros, P. M.; Brito, D.; Cunha, A.; Sawakuchi, H. O.; Moura, J. S.; Yager, P. L.; Krusche, A. V.; Richey, J. E.

2013-12-01

The influence of the Amazon River on global hydrologic and biogeochemical cycling is well recognized. The Amazon River provides roughly 16% of the global freshwater supply to the ocean and is a significant source of CO2 to the atmosphere, outgassing 0.5 Pg C y-1 to the atmosphere--a flux roughly equivalent to the amount of carbon 'sequestered' by the Amazon rainforest (Field et al, 1998; Richey et al., 2002; Malhi et al., 2008). However, much of our understanding of the flux of matter from the Amazon River into the Atlantic Ocean (and atmosphere) is limited to measurements made at and upstream of Óbidos, 900 km upstream from the actual river mouth. Further, there are few to no observations documenting the transformation of organic matter in a parcel of water as it travels downstream of Óbidos into the ocean. Here we explore the hydrological and biogeochemical evolution of the lower Amazon River continuum, from Óbidos to the Atlantic Ocean. A suite of dissolved and particulate organic matter (OM) parameters were measured during a series of five river expeditions with stations at Óbidos, the Tapajós tributary, the mouth of the Lago Grande de Curuai floodplain lake, both the north and south channels of the Amazon River mouth near Macapá, and the confluence of the Amazon and Tocantins Rivers near Belém. In addition to bulk carbon isotopic signatures, a suite of biomarkers including dissolved and particulate lignin-derived phenols were measured to trace the sources and degradation history of terrestrial vascular plant derived OM throughout the continuum. Dissolved and particulate lignin phenol concentrations both correlated positively with river discharge in the Amazon River mainstem, with variable export patterns from the tributaries and floodplains. As organic matter travels along the continuum it is degraded by microbial composition, fuelling gross respiration and CO2 outgassing. The flux of organic carbon to the ocean is chemically recalcitrant as a result of the constant biological processing of labile OM throughout the lower river. We estimate that 40% of the vascular plant-derived organic carbon sequestered by the terrestrial biosphere is degraded within soils, 55% is degraded along the river continuum, and less than 5% is delivered to the ocean (Ward et al., 2013) References Cited Field, C., M. Behrenfeld, J. Randerson, and P. Falkowski. 1998. Primary production of the biosphere: Integrating terrestrial and oceanic components. Science 281, 237-240. Malhi, Y., Roberts, J.T., Betts, R.A., Killeen, T.J., Li, W., Nobre, C.A. 2008. Climate change, deforestation, and the fate of the Amazon. Science 319, 169-172. Richey, J. E., Melack, J. M., Aufdenkampe, A. K., Ballester, V. M. & Hess, L. L. 2002. Outgassing from Amazonian rivers and wetlands as a large tropical source of atmospheric CO2. Nature 416, 617-620. Ward, N.D.; Keil, R.G.; Medeiros, P.M.; Brito, D.C.; Cunha, A.C.; Dittmar, T.; Yager, P.L.; Krusche, A.V.; Richey, J.E. 2013. Degradation of terrestrially derived macromolecules in the Amazon River. Nature Geoscience. doi: 10.1038/ngeo1817

Evaluating the Effects of Different Vegetation Types on Necrophagous Fly Communities (Diptera: Calliphoridae; Sarcophagidae): Implications for Conservation

PubMed Central

Pereira de Sousa, José Roberto; Carvalho-Filho, Fernando da Silva; Juen, Leandro; Esposito, Maria Cristina

2016-01-01

The present study was conducted in five different phytogeographic zones of the Brazilian state of Maranhão, three of which (the Amazon Forest, Cerrado, and Palm Groves) are more heterogeneous, whereas the other two (Marshlands and Mangroves) are more homogeneous. In each zone, nine sites were visited for the collection of necrophagous flies using bait traps in 2010, 2011, and 2012. The calliphorid and sarcophagid communities observed at each site were compared in terms of species richness, composition, and abundance. The more heterogeneous zones had higher species richness, except in the case of the sarcophagids in the forest habitats. The calliphorids Chloroprocta idioidea (Robineau- Desvoidy, 1830), Mesembrinella bicolor (Fabricius, 1805), Hemilucilia semidiaphana (Rondani, 1850) and Lucilia eximia (Wiedemann, 1819) were more closely associated with the Cerrado, Palm Grove and Amazon Forest zones, and Chrysomya megacephala (Fabricius, 194) with the Mangrove. In the sarcophagids, Peckia (Euboettcheria) subducta (Lopes, 1935) and P. (Pattonella) palidipilosa (Curran & Walley, 1934) were associated with the Amazon Forest, and P. (Sarcodexia) lambens (Wiedemann, 1830) and Tricharaea (Sarcophagula) occidua (Fabricius, 1794) with the Palm Grove and Cerrado zones. In the calliphorids, the greatest dissimilarity was recorded between the Amazon Forest and the Mangrove and Lowland grassland zones. In the sarcophagids, by contrast, the greatest dissimilarities were recorded between the Amazon Forest and all the other four zones. In general, then, the phytogeographic zones with the highest environmental heterogeneity were characterized by the greatest species richness and abundance of necrophagous flies. PMID:27798664

Influence of plankton metabolism and mixing depth on CO2 dynamics in an Amazon floodplain lake.

PubMed

Amaral, João Henrique F; Borges, Alberto V; Melack, John M; Sarmento, Hugo; Barbosa, Pedro M; Kasper, Daniele; de Melo, Michaela L; De Fex-Wolf, Daniela; da Silva, Jonismar S; Forsberg, Bruce R

2018-07-15

We investigated plankton metabolism and its influence on carbon dioxide (CO 2 ) dynamics in a central Amazon floodplain lake (Janauacá, 3°23' S, 60°18' W) from September 2015 to May 2016, including a period with exceptional drought. We made diel measurements of CO 2 emissions to the atmosphere with floating chambers and depth profiles of temperature and CO 2 partial pressure (pCO 2 ) at two sites with differing wind exposure and proximity to vegetated habitats. Dissolved oxygen (DO) concentrations were monitored continuously during day and night in clear and dark chambers with autonomous optical sensors to evaluate plankton metabolism. Overnight community respiration (CR), and gross primary production (GPP) rates were higher in clear chambers and positively correlated with chlorophyll-a (Chl-a). CO 2 air-water fluxes varied over 24-h periods with changes in thermal structure and metabolism. Most net daily CO 2 fluxes during low water and mid-rising water at the wind exposed site were into the lake as a result of high rates of photosynthesis. All other measurements indicated net daily release to the atmosphere. Average GPP rates (6.8gCm -2 d -1 ) were high compared with other studies in Amazon floodplain lakes. The growth of herbaceous plants on exposed sediment during an exceptional drought led to large carbon inputs when these areas were flooded, enhancing CR, pCO 2 , and CO 2 fluxes. During the period when the submerged herbaceous vegetation decayed phytoplankton abundance increased and photosynthetic uptake of CO 2 occurred. While planktonic metabolism was often autotrophic (GPP:CR>1), CO 2 out-gassing occurred during most periods investigated indicating other inputs of carbon such as sediments or soils and wetland plants. Copyright © 2018 Elsevier B.V. All rights reserved.

High malnutrition rate in Venezuelan Yanomami compared to Warao Amerindians and Creoles: significant associations with intestinal parasites and anemia.

PubMed

Verhagen, Lilly M; Incani, Renzo N; Franco, Carolina R; Ugarte, Alejandra; Cadenas, Yeneska; Sierra Ruiz, Carmen I; Hermans, Peter W M; Hoek, Denise; Campos Ponce, Maiza; de Waard, Jacobus H; Pinelli, Elena

2013-01-01

Children in rural areas experience the interrelated problems of poor growth, anemia and parasitic infections. We investigated the prevalence of and associations between intestinal helminth and protozoan infections, malnutrition and anemia in school-age Venezuelan children. This cross-sectional study was conducted in 390 children aged 4-16 years from three rural areas of Venezuela: the Amazon Region, Orinoco Delta and Carabobo State. Stool samples were collected for direct parasitic examinations. Anthropometric indicators of chronic (height-for-age Z score) and acute (weight-for-height and Body Mass Index (BMI)-for-age Z score in respectively children under 5 years of age and children aged 5 years and above) malnutrition were calculated. Multivariate linear and logistic regression models were built to determine factors associated with nutritional status and polyparasitism. Hookworm and Strongyloides stercoralis prevalences were highest in children from the Amazon rainforest (respectively 72% and 18%) while children from the Orinoco Delta and Carabobo State showed higher rates of Ascaris lumbricoides (respectively 28% and 37%) and Trichuris trichiura (40% in both regions). The prevalence of Giardia lamblia infection was not significantly different between regions (average: 18%). Anemia prevalence was highest in the Amazon Region (24%). Hemoglobin levels were significantly decreased in children with a hookworm infection. Malnutrition was present in respectively 84%, 30% and 13% of children from the Amazon Region, Orinoco Delta and Carabobo State. In multivariate analysis including all regions, G. lamblia and helminth infections were significantly and negatively associated with respectively height-for-age and weight-for-height/BMI-for-age Z scores. Furthermore, hemoglobin levels were positively associated with the height-for-age Z score (0.11, 95% CI 0.02 - 0.20). In rural populations in Venezuela helminthiasis and giardiasis were associated with acute and chronic nutritional status respectively. These data highlight the need for an integrated approach to control transmission of parasites and improve the health status of rural Venezuelan children.

High Malnutrition Rate in Venezuelan Yanomami Compared to Warao Amerindians and Creoles: Significant Associations WITH Intestinal Parasites and Anemia

PubMed Central

Verhagen, Lilly M.; Incani, Renzo N.; Franco, Carolina R.; Ugarte, Alejandra; Cadenas, Yeneska; Sierra Ruiz, Carmen I.; Hermans, Peter W. M.; Hoek, Denise; Campos Ponce, Maiza; de Waard, Jacobus H.; Pinelli, Elena

2013-01-01

Background Children in rural areas experience the interrelated problems of poor growth, anemia and parasitic infections. We investigated the prevalence of and associations between intestinal helminth and protozoan infections, malnutrition and anemia in school-age Venezuelan children. Methods This cross-sectional study was conducted in 390 children aged 4-16 years from three rural areas of Venezuela: the Amazon Region, Orinoco Delta and Carabobo State. Stool samples were collected for direct parasitic examinations. Anthropometric indicators of chronic (height-for-age Z score) and acute (weight-for-height and Body Mass Index (BMI)-for-age Z score in respectively children under 5 years of age and children aged 5 years and above) malnutrition were calculated. Multivariate linear and logistic regression models were built to determine factors associated with nutritional status and polyparasitism. Results Hookworm and Strongyloides stercoralis prevalences were highest in children from the Amazon rainforest (respectively 72% and 18%) while children from the Orinoco Delta and Carabobo State showed higher rates of Ascaris lumbricoides (respectively 28% and 37%) and Trichuris trichiura (40% in both regions). The prevalence of Giardia lamblia infection was not significantly different between regions (average: 18%). Anemia prevalence was highest in the Amazon Region (24%). Hemoglobin levels were significantly decreased in children with a hookworm infection. Malnutrition was present in respectively 84%, 30% and 13% of children from the Amazon Region, Orinoco Delta and Carabobo State. In multivariate analysis including all regions, G. lamblia and helminth infections were significantly and negatively associated with respectively height-for-age and weight-for-height/BMI-for-age Z scores. Furthermore, hemoglobin levels were positively associated with the height-for-age Z score (0.11, 95% CI 0.02 - 0.20). Conclusions In rural populations in Venezuela helminthiasis and giardiasis were associated with acute and chronic nutritional status respectively. These data highlight the need for an integrated approach to control transmission of parasites and improve the health status of rural Venezuelan children. PMID:24143243

The future of the Amazon: new perspectives from climate, ecosystem and social sciences.

PubMed

Betts, Richard A; Malhi, Yadvinder; Roberts, J Timmons

2008-05-27

The potential loss or large-scale degradation of the tropical rainforests has become one of the iconic images of the impacts of twenty-first century environmental change and may be one of our century's most profound legacies. In the Amazon region, the direct threat of deforestation and degradation is now strongly intertwined with an indirect challenge we are just beginning to understand: the possibility of substantial regional drought driven by global climate change. The Amazon region hosts more than half of the world's remaining tropical forests, and some parts have among the greatest concentrations of biodiversity found anywhere on Earth. Overall, the region is estimated to host about a quarter of all global biodiversity. It acts as one of the major 'flywheels' of global climate, transpiring water and generating clouds, affecting atmospheric circulation across continents and hemispheres, and storing substantial reserves of biomass and soil carbon. Hence, the ongoing degradation of Amazonia is a threat to local climate stability and a contributor to the global atmospheric climate change crisis. Conversely, the stabilization of Amazonian deforestation and degradation would be an opportunity for local adaptation to climate change, as well as a potential global contributor towards mitigation of climate change. However, addressing deforestation in the Amazon raises substantial challenges in policy, governance, sustainability and economic science. This paper introduces a theme issue dedicated to a multidisciplinary analysis of these challenges.

Patterns of Geographic Expansion of Aedes aegypti in the Peruvian Amazon

PubMed Central

Guagliardo, Sarah Anne; Barboza, José Luis; Morrison, Amy C.; Astete, Helvio; Vazquez-Prokopec, Gonzalo; Kitron, Uriel

2014-01-01

Background and Objectives In the Peruvian Amazon, the dengue vector Aedes aegypti is abundant in large urban centers such as Iquitos. In recent years, it has also been found in a number of neighboring rural communities with similar climatic and socioeconomic conditions. To better understand Ae. aegypti spread, we compared characteristics of communities, houses, and containers in infested and uninfested communities. Methods We conducted pupal-demographic surveys and deployed ovitraps in 34 communities surrounding the city of Iquitos. Communities surveyed were located along two transects: the Amazon River and a 95km highway. We calculated entomological indices, mapped Ae. aegypti presence, and developed univariable and multivariable logistic regression models to predict Ae. aegypti presence at the community, household, or container level. Results Large communities closer to Iquitos were more likely to be infested with Ae. aegypti. Within infested communities, houses with Ae. aegypti had more passively-filled containers and were more often infested with other mosquito genera than houses without Ae. aegypti. For containers, large water tanks/drums and containers with solar exposure were more likely to be infested with Ae. aegypti. Maps of Ae. aegypti presence revealed a linear pattern of infestation along the highway, and a scattered pattern along the Amazon River. We also identified the geographical limit of Ae. aegypti expansion along the highway at 19.3 km south of Iquitos. Conclusion In the Peruvian Amazon, Ae. aegypti geographic spread is driven by human transportation networks along rivers and highways. Our results suggest that urban development and oviposition site availability drive Ae. aegypti colonization along roads. Along rivers, boat traffic is likely to drive long-distance dispersal via unintentional transport of mosquitoes on boats. PMID:25101786

Multiangular Contributions for Discriminate Seasonal Structural Changes in the Amazon Rainforest Using MODIS MAIAC Data

NASA Astrophysics Data System (ADS)

Moura, Y. M.; Hilker, T.; Galvão, L. S.; Santos, J. R.; Lyapustin, A.; Sousa, C. H. R. D.; McAdam, E.

2014-12-01

The sensitivity of the Amazon rainforests to climate change has received great attention by the scientific community due to the important role that this vegetation plays in the global carbon, water and energy cycle. The spatial and temporal variability of tropical forests across Amazonia, and their phenological, ecological and edaphic cycles are still poorly understood. The objective of this work was to infer seasonal and spatial variability of forest structure in the Brazilian Amazon based on anisotropy of multi-angle satellite observations. We used observations from the Moderate Resolution Imaging Spectroradiometer (MODIS/Terra and Aqua) processed by a new Multi-Angle Implementation Atmospheric Correction Algorithm (MAIAC) to investigate how multi-angular spectral response from satellite imagery can be used to analyze structural variability of Amazon rainforests. We calculated differences acquired from forward and backscatter reflectance by modeling the bi-directional reflectance distribution function to infer seasonal and spatial changes in vegetation structure. Changes in anisotropy were larger during the dry season than during the wet season, suggesting intra-annual changes in vegetation structure and density. However, there were marked differences in timing and amplitude depending on forest type. For instance differences between reflectance hotspot and darkspot showed more anisotropy in the open Ombrophilous forest than in the dense Ombrophilous forest. Our results show that multi-angle data can be useful for analyzing structural differences in various forest types and for discriminating different seasonal effects within the Amazon basin. Also, multi-angle data could help solve uncertainties about sensitivity of different tropical forest types to light versus rainfall. In conclusion, multi-angular information, as expressed by the anisotropy of spectral reflectance, may complement conventional studies and provide significant improvements over approaches that are based on vegetation indices alone.

Climate Impact on South America due to Land Use Degradation of Amazon Rainforest during Winter and Summer Periods by RegCM3 Model

NASA Astrophysics Data System (ADS)

Silva, M. E. S.; Da Rocha, R.; Pereira, G.

2015-12-01

In this study we investigated the climatic impact over South America region due to the increasing of deforestation at the eastern and southern regions of Amazon through the use of the climate model RegCM3 with 50 km of spatial resolution. Many studies, among global and regional models have been used to simulate climatic impact due to deforestation. Most of them used relatively coarse resolution, small domains over South America, besides do not consider deforestation as usually observed. In order to verify the RegCM3 ability to simulate climate impacts due to Amazon deforestation including relatively higher horizontal resolutions, 50 km, a larger domain, the whole South America, deforested areas more similar to the route-shaped commonly seen, and a landuse updating, the model was run for the 2001-2006 period. As the major part of the previous studies focusing Amazon deforestation, RegCM3-50km simulated over degraded areas air temperature increase, ranging from 1.0 to 2.5oC, and precipitation decreasing, ~10%. These aspects are mainly resulting from soil water depletion and roughness vegetation decreasing, both inhibiting evapotranspiration processes. Apart from these results, the model with 50 km simulated precipitation increasing, ~10%, over the eastern South America and adjacent South Atlantic ocean, after Amazon deforestation. Seeking for physical related reasons able to provide the precipitation increasing during rainy seasons, over eastern South America, we found out that upper levels high pressure system (the Bolivian High) intensification, coupled to the southeastward trough, what follows the low troposphere warming, seems to contribute to the precipitation increasing. The climatic impact simulated for winter seasons presents strongest values for areas with altered landuse, over the north region of South America.

Patterns of geographic expansion of Aedes aegypti in the Peruvian Amazon.

PubMed

Guagliardo, Sarah Anne; Barboza, José Luis; Morrison, Amy C; Astete, Helvio; Vazquez-Prokopec, Gonzalo; Kitron, Uriel

2014-08-01

In the Peruvian Amazon, the dengue vector Aedes aegypti is abundant in large urban centers such as Iquitos. In recent years, it has also been found in a number of neighboring rural communities with similar climatic and socioeconomic conditions. To better understand Ae. aegypti spread, we compared characteristics of communities, houses, and containers in infested and uninfested communities. We conducted pupal-demographic surveys and deployed ovitraps in 34 communities surrounding the city of Iquitos. Communities surveyed were located along two transects: the Amazon River and a 95 km highway. We calculated entomological indices, mapped Ae. aegypti presence, and developed univariable and multivariable logistic regression models to predict Ae. aegypti presence at the community, household, or container level. Large communities closer to Iquitos were more likely to be infested with Ae. aegypti. Within infested communities, houses with Ae. aegypti had more passively-filled containers and were more often infested with other mosquito genera than houses without Ae. aegypti. For containers, large water tanks/drums and containers with solar exposure were more likely to be infested with Ae. aegypti. Maps of Ae. aegypti presence revealed a linear pattern of infestation along the highway, and a scattered pattern along the Amazon River. We also identified the geographical limit of Ae. aegypti expansion along the highway at 19.3 km south of Iquitos. In the Peruvian Amazon, Ae. aegypti geographic spread is driven by human transportation networks along rivers and highways. Our results suggest that urban development and oviposition site availability drive Ae. aegypti colonization along roads. Along rivers, boat traffic is likely to drive long-distance dispersal via unintentional transport of mosquitoes on boats.

Influence of the Amazon River discharge on the biogeography of phytoplankton communities in the western tropical north Atlantic

NASA Astrophysics Data System (ADS)

Goes, Joaquim I.; Gomes, Helga do Rosario; Chekalyuk, Alexander M.; Carpenter, Edward J.; Montoya, Joseph P.; Coles, Victoria J.; Yager, Patricia L.; Berelson, William M.; Capone, Douglas G.; Foster, Rachel A.; Steinberg, Deborah K.; Subramaniam, Ajit; Hafez, Mark A.

2014-01-01

An Advanced Laser Fluorometer (ALF) capable of discriminating several phytoplankton pigment types was utilized in conjunction with microscopic data to map the distribution of phytoplankton communities in the Amazon River plume in May-June-2010, when discharge from the river was at its peak. Cluster analysis and Non-metric Multi-Dimensional Scaling (NMDS) helped distinguish three distinct biological communities that separated largely on the basis of salinity gradients across the plume. These three communities included an "estuarine type" comprised of a high biomass mixed population of diatoms, cryptophytes and green-water Synechococcus spp. located upstream of the plume, a "mesohaline type" made up largely of communities of Diatom-Diazotroph Associations (DDAs) and located in the northwestern region of the plume and an "oceanic type" in the oligotrophic waters outside of the plume made up of Trichodesmium and Synechococcus spp. Although salinity appeared to have a substantial influence on the distribution of different phytoplankton groups, ALF and microscopic measurements examined in the context of the hydro-chemical environment of the river plume, helped establish that the phytoplankton community structure and distribution were strongly controlled by inorganic nitrate plus nitrite (NO3 + NO2) availability whose concentrations were low throughout the plume. Towards the southern, low-salinity region of the plume, NO3 + NO2 supplied by the onshore flow of subsurface (∼80 m depth) water, ensured the continuous sustenance of the mixed phytoplankton bloom. The large drawdown of SiO3 and PO4 associated with this "estuarine type" mixed bloom at a magnitude comparable to that observed for DDAs in the mesohaline waters, leads us to contend that, diatoms, cryptophytes and Synechococcus spp., fueled by the offshore influx of nutrients also play an important role in the cycling of nutrients in the Amazon River plume.

Riethia manauara n. sp., an Amazonian Chironomid (Diptera: Chironomidae) from Brazil.

PubMed

Neubern, C S O; Trivinho-Strixino, S; da Silva, Fabio L

2011-10-01

One new species of Riethia Kieffer, Riethia manauara n. sp., is described and figured as male, pupa and larva. The generic diagnosis for pupae and larvae are emended. The specimens were collected from water systems in the Amazon Rainforest in northern Brazil.

Linking Deforestation to Malaria in the Amazon: Characterization of the Breeding Habitat of the Principal Malaria Vector, Anopheles darlingi

PubMed Central

Vittor, Amy Y.; Pan, William; Gilman, Robert H.; Tielsch, James; Glass, Gregory; Shields, Tim; Sánchez-Lozano, Wagner; Pinedo, Viviana V.; Salas-Cobos, Erit; Flores, Silvia; Patz, Jonathan A.

2009-01-01

This study examined the larval breeding habitat of a major South American malaria vector, Anopheles darlingi, in areas with varying degrees of ecologic alteration in the Peruvian Amazon. Water bodies were repeatedly sampled across 112 km of transects along the Iquitos-Nauta road in ecologically varied areas. Field data and satellite imagery were used to determine the landscape composition surrounding each site. Seventeen species of Anopheles larvae were collected. Anopheles darlingi larvae were present in 87 of 844 sites (10.3%). Sites with A. darlingi larvae had an average of 24.1% forest cover, compared with 41.0% for sites without A. darlingi (P < 0.0001). Multivariate analysis identified seasonality, algae, water body size, presence of human populations, and the amount of forest and secondary growth as significant determinants of A. darlingi presence. We conclude that deforestation and associated ecologic alterations are conducive to A. darlingi larval presence, and thereby increase malaria risk. PMID:19556558

Rapid neodymium release to marine waters from lithogenic sediments in the Amazon estuary

PubMed Central

Rousseau, Tristan C. C.; Sonke, Jeroen E.; Chmeleff, Jérôme; van Beek, Pieter; Souhaut, Marc; Boaventura, Geraldo; Seyler, Patrick; Jeandel, Catherine

2015-01-01

Rare earth element (REE) concentrations and neodymium isotopic composition (ɛNd) are tracers for ocean circulation and biogeochemistry. Although models suggest that REE release from lithogenic sediment in river discharge may dominate all other REE inputs to the oceans, the occurrence, mechanisms and magnitude of such a source are still debated. Here we present the first simultaneous observations of dissolved (<0.45 μm), colloidal and particulate REE and ɛNd in the Amazon estuary. A sharp drop in dissolved REE in the low-salinity zone is driven by coagulation of colloidal matter. At mid-salinities, total dissolved REE levels slightly increase, while ɛNd values are shifted from the dissolved Nd river endmember (−8.9) to values typical of river suspended matter (−10.6). Combining a Nd isotope mass balance with apparent radium isotope ages of estuarine waters suggests a rapid (3 weeks) and globally significant Nd release by dissolution of lithogenic suspended sediments. PMID:26158849

Climate drivers of the Amazon forest greening.

PubMed

Wagner, Fabien Hubert; Hérault, Bruno; Rossi, Vivien; Hilker, Thomas; Maeda, Eduardo Eiji; Sanchez, Alber; Lyapustin, Alexei I; Galvão, Lênio Soares; Wang, Yujie; Aragão, Luiz E O C

2017-01-01

Our limited understanding of the climate controls on tropical forest seasonality is one of the biggest sources of uncertainty in modeling climate change impacts on terrestrial ecosystems. Combining leaf production, litterfall and climate observations from satellite and ground data in the Amazon forest, we show that seasonal variation in leaf production is largely triggered by climate signals, specifically, insolation increase (70.4% of the total area) and precipitation increase (29.6%). Increase of insolation drives leaf growth in the absence of water limitation. For these non-water-limited forests, the simultaneous leaf flush occurs in a sufficient proportion of the trees to be observed from space. While tropical cycles are generally defined in terms of dry or wet season, we show that for a large part of Amazonia the increase in insolation triggers the visible progress of leaf growth, just like during spring in temperate forests. The dependence of leaf growth initiation on climate seasonality may result in a higher sensitivity of these ecosystems to changes in climate than previously thought.

Amazon river basin evapotranspiration and its influence on the rainfall in southern Brazil

NASA Astrophysics Data System (ADS)

Folegatti, M. V.; Wolff, W.

2017-12-01

Amazon river basin (ARB) presents a positive water balance, i.e. the precipitation is higher than evapotranspiration. Regarding the regional circulation, ARB evapotranspiration represents an important source of humidity for the South of Brazil. Thus, the aim of this work is to answer the question: how much is the correlation between ARB evapotranspiration and rainfall in South of Brazil? The shapefiles data of ARB and countries/states boundary were obtained through the Oak Ridge National Laboratory (ORNL) and Instituto Brasileiro de Geografia e Estatística (IBGE), respectively. According to rasters data, the precipitation was obtained from study of Numerical Terradynamic Simulation Group (NTSG) for images of Moderate Resolution Imaging Spectroradiometer (MODIS), under code MOD16A2, whereas rasters data for evapotranspiration were obtained from National Aeronautics and Space Administration (NASA) by Tropical Rainfall Measuring Mission Multi-Satellite Precipitation Analysis (TMPA), under code 3B43_V7. The products MOD16A2 and 3B43_V7 have a respective spatial resolution of 0.5º and 0.25º, and a monthly temporal resolution from January/2000 to December/2014. For ARB and South region of Brazil was calculated the mean evapotranspiration and mean precipitation through the pixels within of the respective polygons. To answer the question of this work was performed the cross-correlation analysis between these time series. We observed the highest value for the lag that corresponds the begin of spring (October), being 0.3 approximately. As a result, the mean precipitation on South region of Brazil during spring and summer was in the order of 15% to 30 %, explained by ARB evapotranspiration. For this reason, the maintenance of ARB is extremely important for water resource grant in South of Brazil.

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 cropsWe explored correlations between groups and the extent of agricultural lands PMID:26709335

Emergent Hydrological Regimes in Amazonia Determine Vegetation Productivity and Structure.

NASA Astrophysics Data System (ADS)

Ahlström, A.; Canadell, J.; Schurgers, G.; Berry, J. A.; Guan, K.; Jackson, R. B.

2016-12-01

The Amazon rain forest has a disproportionate significance for global CO2 storage and biodiversity. Earth system models (ESMs) that estimate future climate and vegetation show little agreement in simulations in Amazonia. Here we show that evapotranspiration (ET), gross primary productivity (GPP) and above ground biomass in both models and empirical data align on an emergent hydrologically determined relationship that describes a functional relationship with annual precipitation (P). The physical relationship describes the potential for plant productivity and has a breakpoint at 2000 mm annual precipitation, where the system transitions between water and radiation limitation of annual ET. While ESM GPP is generally underestimated due to a low-bias in their internally generated P, their response to annual precipitation generally matches empirical data. It is different for biomass: ESMs show some ability in capturing biomass levels in the energy-limited wet hydrological regime above 2000 mm annual precipitation but they do not fully capture the biomass structure tipping point found in empirical data at the hydrological regime breakpoint that coincide with the forest-savanna transition. This discrepancy is likely due to the relatively simple representation of disturbances, primarily fires, and vegetation dynamics found in ESMs, and implies that ESMs likely overestimate the resilience to a potential future drying of the Amazon. Future elevated CO2 may increase plant water use efficiency and shift GPP upwards, but it will not affect the breakpoint between the regimes or the susceptibility of the forest which are both determined by precipitation and its role in determining the hydrological regime. This analysis reconciles and explains the findings of many studies on the Amazon. Our results suggests that future Amazonian biomass is governed by changes in precipitation, vegetation dynamics and disturbances, none of which are well predicted and represented by ESMs. Improvements of these processes are the most pressing challenges for more accurate future predictions on the fate of the Amazon and the global tropics.

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

PubMed

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

2015-06-01

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

Civil-Military Collaboration to Address Adaptation to Climate Change in South America

DTIC Science & Technology

2011-03-01

drought, water scarcity and soil degradation, intensify land use conflicts (especially in the Andean and Amazon Regions) and trigger environmentally...of the territories , climatic variability, and food scarcity are common problems for many of the countries of the region, which are in dire need to...resource conflicts. Because climate change can further affect such environmental issues as water, forests , soil fertility, hunger, disease, health, and

Influence of the Amazon Hydrological Regime on Eutrophication Indicators of a Hydroelectric Power Plant Reservoir.

PubMed

Freire, Jean Carlos A; Hauser-Davis, Rachel Ann; da Costa Lobato, Tarcísio; de Morais, Jefferson M; de Oliveira, Terezinha F; F Saraiva, Augusto Cesar

2017-05-01

Dam constructions in the Amazon have increased exponentially in the last decades, causing several environmental impacts and serious anthropogenic impacts in certain hydroelectric power plant reservoirs in the region have been identified. The assessment of the trophic status of these reservoirs is of interest to indicate man-made changes in the environment, but must take into account the hydrological cycle of the area. This can be relevant for environmental management actions, aiding in the identification of the ecological status of water bodies. In this context, physico-chemical parameters and eutrophication indicators were determined in a hydroelectric power plant reservoir in the Brazilian Amazon to assess trophic variations during the regional hydrological regime phases on the reservoir, namely dry, filling, full and emptying stages. The local hydrological regimes were shown to significantly influence TSS and turbidity, as well as NH 4 , NO 3 , PO 4 , with higher values consistently observed during the filling stage of the reservoir. In addition, differences among the sampling stations regarding land use, population and anthropogenic activities were reflected in the PO 4 3- values during the different hydrological phases.

Water Stress Impacts Tree-Atmosphere Interaction in the Amazon

NASA Astrophysics Data System (ADS)

van Emmerik, T. H. M.; Steele-Dunne, S. C.; Gentine, P.; Oliveira, R. S.; Van De Giesen, N.

2017-12-01

Land-atmosphere interactions depend on momentum exchange from the atmosphere to the canopy, which depends on the tree drag coefficient. It is known that the drag coefficient, and thus tree-atmosphere interaction, can vary strongly within a canopy. Yet, only few measurements are available to study the variation of tree-atmosphere interaction in time and space, and in response to vegetation water stress. Recent work [1] demonstrated how accelerometers can be used to study tree properties and responses. For this study, accelerometers were used to derive a measure of tree-atmosphere interaction for 19 individual trees of seven different species in the Brazilian Amazon. This study demonstrates that under field conditions, tree-atmosphere interaction can vary considerably in time and space. The five month measurement period included the transitioning from the wet to the dry season. We demonstrate that increased tree water deficit, measured with dendrometers, is related to observed changes in tree-atmosphere interaction, which is hypothesized to be caused by water stress induced changes in tree mass. References [1]. van Emmerik, T.; Steele-Dunne, S.; Hut, R.; Gentine, P.; Guerin, M.; Oliveira, R.S.; Wagner, J.; Selker, J.; van de Giesen, N. Measuring Tree Properties and Responses Using Low-Cost Accelerometers. Sensors 2017, 17, 1098.

Sources and routing of the Amazon River Flood Wave

NASA Astrophysics Data System (ADS)

Richey, Jeffrey E.; Mertes, Leal A. K.; Dunne, Thomas; Victoria, Reynaldo L.; Forsberg, Bruce R.; Tancredi, AntôNio C. N. S.; Oliveira, Eurides

1989-09-01

We describe the sources and routing of the Amazon River flood wave through a 2000-km reach of the main channel, between São Paulo de Olivença and Obidos, Brazil. The damped hydrograph of the main stem reflects the large drainage basin area, the 3-month phase lag in peak flows between the north and south draining tributaries due to seasonal differences in precipitation, and the large volume of water stored on the floodplain. We examined several aspects of the valley floor hydrology that are important for biogeochemistry. These include volumes of water storage in the channel and the floodplain and the rates of transfer between these two storage elements at various seasons and in each segment of the valley. We estimate that up to 30% of the water in the main stem is derived from water that has passed through the floodplain. To predict the discharge at any cross section within the study reach, we used the Muskingum formula to predict the hydrograph at downriver cross sections from a known hydrograph at upstream cross-sections and inputs and outputs along each reach. The model was calibrated using three years of data and was successfully tested against an additional six years of data. With this model it is possible to interpolate discharges for unsampled times and sites.

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

NASA Technical Reports Server (NTRS)

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

2007-01-01

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

Drought stress and carbon uptake in an Amazon forest measured with spaceborne imaging spectroscopy

PubMed Central

Asner, Gregory P.; Nepstad, Daniel; Cardinot, Gina; Ray, David

2004-01-01

Amazônia contains vast stores of carbon in high-diversity ecosystems, yet this region undergoes major changes in precipitation affecting land use, carbon dynamics, and climate. The extent and structural complexity of Amazon forests impedes ground studies of ecosystem functions such as net primary production (NPP), water cycling, and carbon sequestration. Traditional modeling and remote-sensing approaches are not well suited to tropical forest studies, because (i) biophysical mechanisms determining drought effects on canopy water and carbon dynamics are poorly known, and (ii) remote-sensing metrics of canopy greenness may be insensitive to small changes in leaf area accompanying drought. New spaceborne imaging spectroscopy may detect drought stress in tropical forests, helping to monitor forest physiology and constrain carbon models. We combined a forest drought experiment in Amazônia with spaceborne imaging spectrometer measurements of this area. With field data on rainfall, soil water, and leaf and canopy responses, we tested whether spaceborne hyperspectral observations quantify differences in canopy water and NPP resulting from drought stress. We found that hyperspectral metrics of canopy water content and light-use efficiency are highly sensitive to drought. Using these observations, forest NPP was estimated with greater sensitivity to drought conditions than with traditional combinations of modeling, remote-sensing, and field measurements. Spaceborne imaging spectroscopy will increase the accuracy of ecological studies in humid tropical forests. PMID:15071182

Numerical investigations with WRF about atmospheric features leading to heavy precipitation and flood events over the Central Andes' complex topography

NASA Astrophysics Data System (ADS)

Zamuriano, Marcelo; Brönnimann, Stefan

2017-04-01

It's known that some extremes such as heavy rainfalls, flood events, heatwaves and droughts depend largely on the atmospheric circulation and local features. Bolivia is no exception and while the large scale dynamics over the Amazon has been largely investigated, the local features driven by the Andes Cordillera and the Altiplano is still poorly documented. New insights on the regional atmospheric dynamics preceding heavy precipitation and flood events over the complex topography of the Andes-Amazon interface are added through numerical investigations of several case events: flash flood episodes over La Paz city and the extreme 2014 flood in south-western Amazon basin. Large scale atmospheric water transport is dynamically downscaled in order to take into account the complex topography forcing and local features as modulators of these events. For this purpose, a series of high resolution numerical experiments with the WRF-ARW model is conducted using various global datasets and parameterizations. While several mechanisms have been suggested to explain the dynamics of these episodes, they have not been tested yet through numerical modelling experiments. The simulations captures realistically the local water transport and the terrain influence over atmospheric circulation, even though the precipitation intensity is in general unrealistic. Nevertheless, the results show that Dynamical Downscaling over the tropical Andes' complex terrain provides useful meteorological data for a variety of studies and contributes to a better understanding of physical processes involved in the configuration of these events.

River Mixing in the Amazon as a Driver of Concentration-Discharge Relationships

NASA Astrophysics Data System (ADS)

Bouchez, Julien; Moquet, Jean-Sébastien; Espinoza, Jhan Carlo; Martinez, Jean-Michel; Guyot, Jean-Loup; Lagane, Christelle; Filizola, Naziano; Noriega, Luis; Hidalgo Sanchez, Liz; Pombosa, Rodrigo

2017-11-01

Large hydrological systems aggregate compositionally different waters derived from a variety of pathways. In the case of continental-scale rivers, such aggregation occurs noticeably at confluences between tributaries. Here we explore how such aggregation can affect solute concentration-discharge (C-Q) relationships and thus obscure the message carried by these relationships in terms of weathering properties of the Critical Zone. We build up a simple model for tributary mixing to predict the behavior of C-Q relationships during aggregation. We test a set of predictions made in the context of the largest world's river, the Amazon. In particular, we predict that the C-Q relationships of the rivers draining heterogeneous catchments should be the most "dilutional" and should display the widest hysteresis loops. To check these predictions, we compute 10 day-periodicity time series of Q and major solute (Si, Ca2+, Mg2+, K+, Na+, Cl-, SO42-) C and fluxes (F) for 13 gauging stations located throughout the Amazon basin. In agreement with the model predictions, C-Q relationships of most solutes shift from a fairly "chemostatic" behavior (nearly constant C) at the Andean mountain front and in pure lowland areas, to more "dilutional" patterns (negative C-Q relationship) toward the system mouth. More prominent C-Q hysteresis loops are also observed at the most downstream stations. Altogether, this study suggests that mixing of water and solutes between different flowpaths exerts a strong control on C-Q relationships of large-scale hydrological systems.

Distribution of hepatitis C virus genotypes among different exposure categories in the State of Pará, Brazilian Amazon.

PubMed

Sawada, Leila; Pinheiro, Andréia Cristina Costa; Locks, Daiane; Pimenta, Adriana do Socorro Coelho; Rezende, Priscila Rocha; Crespo, Deborah Maia; Crescente, José Ângelo Barletta; Lemos, José Alexandre Rodrigues de; Oliveira Filho, Aldemir Branco de

2011-01-01

Epidemiological studies concerning HCV genotypic distribution in the Brazilian Amazon are scarce. Thus, this study determined the patterns of distribution of HCV genotypes among different exposure categories in the State of Pará, Brazilian Amazon. A cross-sectional study was conducted on 312 HCV-infected individuals belonging to different categories of exposure, who were attended at the HEMOPA, CENPREN and a private hemodialysis clinic in Belém. They were tested for HCV antibodies using an immunoenzymatic test, RNA-HCV, using real-time PCR and HCV genotyping through phylogenetic analysis of the 5' UTR. The population groups were epidemiologically characterized according to data collected in a brief interview or medical consultation. Genotype 1 predominated in all the different categories of HCV exposure. HCV genotypic distribution among blood donors comprised genotypes 1 (94%) and 3 (6%). All patients with chronic hematologic diseases had HCV genotype 1. The genotypic distribution in illicit-drug users comprised genotypes 1 (59.6%) and 3 (40.4%). In patients under hemodialysis, genotypes 1 (90.1%), 2 (3.3%), and 3 (6.6%) were detected. Finally, the frequency of genotypes 1 and 3 was significantly different between the groups: BD and DU, PUH and DU, PUH and PCHD and PCHD and DU. The genotypic frequency and distribution of HCV in different categories of exposure in the State of Pará showed a predominance of genotype 1, regardless of the possible risk of infection.

Mechanisms for the formation and growth of nanometer-sized particles in the Amazon: New insights from GoAmazon2014 and the Tapajos Upwind Forest Flux Study (TUFFS).

NASA Astrophysics Data System (ADS)

Smith, J. N.; Park, J. H.; Kuang, C.; Bustillos, J. O. V.; Souza, R. A. F. D.; Wiedemann, K. T.; Munger, J. W.; Wofsy, S. C.; Rizzo, L. V.; Artaxo, P.; Martin, S. T.; Seco, R.; Kim, S.; Guenther, A. B.; Batalha, S. S. A.; Alves, E. G.; Tota, J.

2014-12-01

The Amazon rainforest is a unique and important place for studying aerosol formation and its impacts on atmospheric chemistry and climate. In remote areas, the atmosphere is characterized by low particle number concentrations and high humidity; perturbations in the particle number concentrations and climate-relevant physical and chemical properties could therefore have a great impact on cloud formation and thus on regional climate and precipitation. While it was previously believed that new particle formation occurs rarely in the Amazon, observations in the Amazon of a sustained steady-state particle number concentration, along with an abundance of dry and wet surfaces upon which particles may deposit, imply that sources of new particles must exist in this region. We present observations from two studies, GOAmazon2014 and Tapajos Upwind Forest Flux Study (TUFFS), which seek to identify and quantify the sources of aerosol particles in the Amazon. Measurements of the chemical composition of 20 - 100 nm diameter aerosol particles at the T3 measurement site during the wet and dry season campaigns of GOAmazon2014 show the presence of inorganic ions such as potassium ion and sulfate, as well as organic ion such as oxalate, in ambient nanoparticles. These observations, combined with 1.5 - 300 nm diameter particle number size distributions and trace gas measurements of organic compounds and sulfuric acid, are used to determine the relative importance of sulfuric acid, organic compounds, and primary biological particle emissions to nanoparticle formation and growth. Observations of 3 - 100 nm diameter particle number size distributions at the KM67 tower site during TUFFS show frequent new particle formation events during the wet season in April, transitioning to a scenario of less frequent events in July at the onset of the dry season. These observations highlight the regional nature of new particle formation in the Amazon, and suggest that additional observations at a variety of locales are needed to fully understand the roles of new particle formation in this region.

Use of morphometric soil aggregates parameters to evaluate the reclamation process in mined areas located at amazon forest - Brazil

NASA Astrophysics Data System (ADS)

Ribeiro, A. I.; Fengler, F. H.; Longo, R. M.; Mello, G. F.; Damame, D. B.; Crowley, D. E.

2015-12-01

Brazil has a high mineral potential that have been explored over the years. A large fraction of these mineral resources are located in Amazon region, which is known for its large biodiversity and world climate importance. As the policies that control the Amazon preservation are relatively new, several mining activities have been exploring the Amazon territory, promoting a large process of degradation. Once the mining activities have a high potential of environmental changes the government created polices to restrain the mining in Amazon forests and obligate mining companies to reclaim theirs minded areas. However, the measurement of reclamation development still is a challenging task for the Professionals involved. The volume and complexity of the variables, allied to the difficulty in identifying the reclamation of ecosystem functionalities are still lack to ensure the reclamation success. In this sense this work aims to investigate the representativeness of morphometric soil aggregates parameters in the understanding of reclamation development. The study area is located in the National Forest of Jamari, State of Rondônia. In the past mining companies explored the region producing eight closed mines that are now in reclamation process. The soil aggregates morphometric measurements: geometric mean diameter (GMD), aggregate circularity index, and aggregate roundness, were choose based in its obtaining facility, and their association to biological activity. To achieve the proposed objective the aggregates of eight sites in reclamation, from different closed mines, where chosen and compared to Amazon forest and open mine soil aggregates. The results were analyzed to one way ANOVA to identifying differences between areas in reclamation, natural ecosystem, and open mine. It was obtained differences for GMD and circularity index. However, only the circularity index allowed to identifying differences between the reclamation sites. The results allowed concluding: (1) Morphometric aggregates measurements can represent the reclamation process in Amazon territory; (2) To validate the results more areas in reclamation process in different ecosystems must be investigated; (3) Roundness didn't represented any differences.Key words: circularity index, ecosystem, geometric mean diameter.

Color vision impairment with low-level methylmercury exposure of an Amazonian population - Brazil.

PubMed

Feitosa-Santana, Claudia; Souza, Givago da Silva; Sirius, Esaú Ventura Pupo; Rodrigues, Anderson Raiol; Cortes, Maria Izabel Tentes; Silveira, Luiz Carlos de Lima; Ventura, Dora Fix

2018-05-01

Land exploitation that follows deforestation and mining can result in soil erosion and the release of mercury to the waters of rivers in the Amazon Basin. Inorganic mercury is methylated by bacteria that are present in the environment and it serves as a source of human contamination through fish consumption in the form of methylmercury. Long-term exposure to low-level methylmercury in the riverside populations can lead to nervous system alterations, some of which are visual impairments such as loss of luminance contrast sensitivity, restricted visual fields and color vision defects. The present study sought to examine color vision in a group of adults living in the central Brazilian Amazon who were exposed to low-levels of methylmercury. Total Hg concentrations were measured from hair collected at the time of the testing. The D15d and FM100 color vision arrangement tests were applied in a population of 36 (22 males) and 42 (25 males), respectively. Controls were healthy volunteers from the cities of São Paulo for the D15d and Belém for the FM100. There was a statistically significant difference in performance between those who were exposed and controls for both tests (p < 0.01 and p < 0.0001, respectively, Mann-Whitney U test), meaning that adults living in this region of the Amazon made more mistakes on both tests when compared to controls. A linear regression was performed using Hg concentrations and test scores. Hg concentrations accounted for 7% and 2% of color D15d and FM100 arrangement test errors, respectively. Although other studies have previously found color vision impairment in the Amazon, they tested inhabitants on the east side of the Amazon, while this study was conducted in the central Amazon region and it is the first study in a population with no direct contact with the Hg source of contamination. These results suggest that long-term exposure to low-level methylmercury in riverside populations is more widely spread in the Amazon Basin than previously reported. This information is needed to implement public health policies that will ensure a safer environment for the Amazonian population. Copyright © 2018 Elsevier B.V. All rights reserved.

Four years of ozone measurements in the Central Amazon - Effects of increasing deforestation rates and different meteorological conditions on near surface concentrations

NASA Astrophysics Data System (ADS)

Wolff, Stefan; Tsokankunku, Anywhere; Pöhlker, Christopher; Saturno, Jorge; Walter, David; Ditas, Florian; Könemann, Tobias; Ganzeveld, Laurens; Yañez-Serrano, Ana Maria; Souza, Rodrigo; Trebs, Ivonne; Sörgel, Matthias

2017-04-01

The ATTO (Amazon Tall Tower Observatory) site (02°08'38.8''S, 58°59'59.5''W) is located in the remote Amazon rainforest, allowing atmospheric and forest studies away from nearby anthropogenic emission sources. Starting with continuous measurements of vertical mixing ratio profiles of H2O, CO2 and O3 in April 2012 at 8 heights between 0.05 m and 80 m above ground, the longest continuous record of near surface O3 in the Amazon rainforest was established. Black carbon (BC), CO and micrometeorological measurements are available for the same period. During intensive campaigns, NOx was measured as well using the same profile system, and, therefore several month of simultaneous NOx measurements are available. During a period of about four months also direct flux measurements of O3 are available. Here, we analyze the long term and seasonal variability of near surface O3 mixing ratios with respect to air pollution, deposition and transport. The Central Amazon is characterized by a clear seasonal precipitation pattern (ca. 350 mm around March and ca. 80 mm around September), correlating strongly with ozone mixing ratios. Since 2012 deforestation rates have increased again in the Amazon, leading to higher air pollution especially during the drier season in the last years. For several strong pollution events we compared the effects of long and short distance biomass burning on O3 and NOx mixing ratios using back trajectories and satellite data. By comparing O3 mixing ratios with solar radiation, Bowen ratio, several trace gases and aerosol loads (Volatile Organic Compounds, CO and BC), different correlation patterns throughout the year that are linked to the sources (transport of O3 and precursors) and sinks (stomatal uptake and chemical reactions) are investigated. For example, the last months of 2015 were strongly influenced by an extraordinary El Niño phenomenon, leading to much drier conditions and enhanced biomass burning in the Amazon, which prolonged the period of increased O3 values. These exceptional dry conditions and a slight La Niña in 2016 have influenced the water availability, which in turn may have affected the O3 deposition.

Metagenomics of the Water Column in the Pristine Upper Course of the Amazon River

PubMed Central

McMahon, Katherine D.; Toyama, Danyelle; Rinke, Raquel; Cristina Souza de Oliveira, Tereza; Wagner Garcia, José; Pellon de Miranda, Fernando; Henrique-Silva, Flavio

2011-01-01

River water is a small percentage of the total freshwater on Earth but represents an essential resource for mankind. Microbes in rivers perform essential ecosystem roles including the mineralization of significant quantities of organic matter originating from terrestrial habitats. The Amazon river in particular is famous for its size and importance in the mobilization of both water and carbon out of its enormous basin. Here we present the first metagenomic study on the microbiota of this river. It presents many features in common with the other freshwater metagenome available (Lake Gatun in Panama) and much less similarity with marine samples. Among the microbial taxa found, the cosmopolitan freshwater acI lineage of the actinobacteria was clearly dominant. Group I Crenarchaea and the freshwater sister group of the marine SAR11 clade, LD12, were found alongside more exclusive and well known freshwater taxa such as Polynucleobacter. A metabolism-centric analysis revealed a disproportionate representation of pathways involved in heterotrophic carbon processing, as compared to those found in marine samples. In particular, these river microbes appear to be specialized in taking up and mineralizing allochthonous carbon derived from plant material. PMID:21915244

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

NASA Astrophysics Data System (ADS)

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

2014-05-01

Three-quarters of the area of flooded land in the world are temporary wetlands (Downing, 2009), which play a significant role in the global carbon cycle(Einsele et al., 2001; Cole et al., 2007; Battin et al., 2009; Abril et al., 2013). Previous studies of the Amazonian floodplain lakes (várzeas), one important compartment of wetlands, showed that the sedimentation of organic carbon (OC) in the floodplain lakes is strongly linked to the periodical floods and to the biogeography from upstream to downstream(Victoria et al., 1992; Martinelli et al., 2003). However, the main sources of sedimentary OC remain uncertain. Hence, the study of the sources of OC buried in floodplain lake sediments can enhance our understanding of the carbon balance of the Amazon ecosystems. In this study, we investigated the seasonal and spatial pattern of sedimentary organic matter in five floodplain lakes of the central Amazon basin (Cabaliana, Janauaca, Canaçari, Miratuba, and Curuai) which have different morphologies, hydrodynamics and vegetation coverage. Surface sediments were collected in four hydrological seasons: low water (LW), rising water (RW), high water (HW) and falling water (FW) in 2009 and 2010. We investigated commonly used bulk geochemical tracers such as C:N ratio and stable isotopic composition of organic carbon (δ13COC). These results were compared with lignin-phenol parameters as an indicator of vascular plant detritus (Hedges and Ertel, 1982) and branched glycerol dialkyl glycerol tetraethers (brGDGTs) to trace the soil OC from land to the aquatic settings (Hopmans et al., 2004). Our data showed that during the RW and FW seasons, the concentration of lignin and brGDGTs were higher in comparison to other seasons. Our study also indicated that floodplain lake sediments primarily consisted of a mixture of C3 plant detritus and soil OC. However, a downstream increase in C4 plant-derived OC contribution was observed along the gradient of increasingly open waters, i.e. from upstream to downstream. We also identify the OC contribution from the seasonally flooded forests, i.e. temporary wetlands as the most important source of sedimentary OC in floodplain lakes. Accordingly, we attribute temporal and spatial difference in sedimentary OC composition to the hydrological connectivity between the Amazon River and its floodplain lakes and thus between the surrounding forests and the floodplain lakes. References: Abril, G., J.-M.Martinez, Artigas, L.F., Moreira-Turcq, P., Benedetti, M.P., Vidal, L., Meziane, T., Kim, J.-H., Bernardes, M.C., Savoye, N., Deborde, J., Albéric, P., Souza, M.F.L., Souza, E.L., Roland, F. Amazon River carbon dioxide outgassing fuelled by wetlands. Nature accepted (2013). Battin, T.J., Luyssaert, S., Kaplan, L.A., Aufdenkampe, A.K., Richter, A., Tranvik, L.J., 2009. The boundless carbon cycle. Nature Geoscience 2, 598 - 600 (2009). Cole, J.J., Prairie, Y.T., Caraco, N.F., McDowell, W.H., Tranvik, L.J., Striegl, R.G., Duarte, C.M., Kortelainen, P., Downing, J.A., Middelburg, J.J., Melack, J. Plumbing the Global Carbon Cycle: Integrating Inland Waters into the Terrestrial Carbon Budget. Ecosystems 10, 171 - 184 (2007). Downing, J. A. Global limnology: up-scaling aquatic services and processes to planet Earth. Verh Internat Verein Limnol 30, 1149.-1166 (2009). Einsele, G., Yan, J., Hinderer, M. Atmospheric carbon burial in modern lake basins and its significance for the global carbon budget. Global and Planetary Change 30, 167 - 195 (2001). Hedges, J.I., Ertel, J.R. Characterization of Lignin by Gas Capillary Chromatography of Cupric Oxide Oxidation Products. Analitical Chemistry 54, 174-178 (1982). Hopmans, E.C., Weijers, J.W.H., Schefu, E., Herfort, L., Damste, J.S.S., Schouten, S.,. A novel proxy for terrestrial organic matter in sediments based on branched and isoprenoid tetraether lipids. Earth and Planetary Science Letters 224, 107 - 116 (2004). Martinelli, L.A., Victoria, R.L., Camargo, P.B.d., Piccolo, M.d.C., Mertes, L., Richey, J.E., Devol, A.H., Forsberg, B.R.. Inland variability of carbon-nitrogen concentrations and d13C in Amazon floodplain (várzea) vegetation and sediment. Hydrol. Process. 17, 1419-1430 (2003). Victoria, R.L., Martinelli, L.A., Trivelin, P.C.O., Matsui, E., Forsberg, B.R., Richey, J.E., Devol, A.H.. The use of stable isotopes in studies of nutrient cycling: Carbon Isotope composition of Amazon varzea sediments. Biotropica 24, 240-249 (1992).

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

NASA Astrophysics Data System (ADS)

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

2009-12-01

There is growing evidence that the majority of the Amazon rainforest survived the climatic threshold of the last ice age. This information is crucial given that this region could be currently near its critical resiliency tipping point; thus, minor climate warming, widespread reductions in precipitation and lengthening of the dry season may be sufficient to gradually contribute to the forest dieback and biodiversity loss [Cowling et al., 2004; Lenton et al., 2008; Maslin, 2004]. To contribute to this knowledge, palaeoclimatic oscillations have been identified in this study by using fossil organic compounds synthesized by marine and terrestrial flora and later accumulated on sediment strata (MD03-2616, 7N, 53W, -1233 meters below sea-level) from the Guianas region, closely linked to the Amazon Basin. Different indicators have been considered to continuously reconstruct the climate over the past 420,000 years at centennial scale: average annual sea surface temperatures (SST, Uk’37), productivity of the coccolithophora flora (alken-2-ones), continental vegetation variability (long chain n-alkanes) and changes in oxygenation of the deep-sea floor (ratio between n-alkan-1-ols and n-alkanes). At present, the Guianas region is largely influenced by migration of the intertropical convergence zone (ITCZ), related temperature and wind patterns, together with changes in hydrological conditions, atmospheric and oceanic fronts. Annual SST is 27.7C; two rain seasons and two dry seasons occur. At the core location, surface waters present complex seasonal configuration, while oxygen-enriched and low-salinity Antarctic Intermediate waters (AAIW) flow northward from -700 to -1500 meters depth; the Upper North Atlantic Deep waters circulate southward at greater depths [World Meteo. Org.; Masson & Delecluse, 2001; Arz et al., 2001]. This study reveals that completely different hydrological conditions and much colder climate occurred in the past, e.g. a harsh drop in SST of up to 24C was recorded over Marine Isotope Stage (MIS) 8. Additionally, warmer periods occurred during the early Holocene (SST=28.1C) or the last interglacial (MIS 5e, 29C). Temperatures similar to present were observed during MIS 11c (28C). Autochthonous marine productivity traced dependence between vertical stratification of the surface water, trade wind strength and precession motion between northern hemisphere spring and perihelion, consistent with previous results [Lopez-Otalvaro et al., 2009]. Recurring surface and deep water destabilizations have been identified. Fluvial continental contributions, reached maximal values during cold events, when the Amazon River plume extended to the core location. Ventilation variability at the core site was modulated by the eccentricity of the Earth’s orbit. Rapid oxygenation changes were more pronounced during deglaciations and interglacials, but tending to decrease, gradually or abruptly, while glacials progressed.

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

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

Cumulative Total South America Freshwater Losses as Seen by NASA GRACE, 2002-15

NASA Image and Video Library

2015-12-08

Cumulative total freshwater losses in South America from 2002 to 2015 (in inches) observed by NASA's Gravity Recovery and Climate Experiment (GRACE) mission. Total water refers to all of the snow, surface water, soil water and groundwater combined. Much of the Amazon River basin experienced increasing total water storage during this time period, though the persistent Brazilian drought is apparent to the east. Groundwater depletion strongly impacted total water losses in the Guarani aquifer of Argentina and neighboring countries. Significant water losses due to the melting ice fields of Patagonia are also observed. http://photojournal.jpl.nasa.gov/catalog/PIA20205

D Hydrodynamics Simulation of Amazonian Seasonally Flooded Wetlands

NASA Astrophysics Data System (ADS)

Pinel, S. S.; Bonnet, M. P.; Da Silva, J. S.; Cavalcanti, R., Sr.; Calmant, S.

2016-12-01

In the low Amazonian basin, interactions between floodplains and river channels are important in terms of water exchanges, sediments, or nutrients. These wetlands are considered as hotspot of biodiversity and are among the most productive in the world. However, they are threatened by climatic changes and anthropic activities. Hence, considering the implications for predicting inundation status of floodplain habitats, the strong interactions between water circulation, energy fluxes, biogeochemical and ecological processes, detailed analyses of flooding dynamics are useful and needed. Numerical inundation models offer means to study the interactions among different water sources. Modeling floods events in this area is challenging because flows respond to dynamic hydraulic controls coming from several water sources, complex geomorphology, and vegetation. In addition, due to the difficulty of access, there is a lack of existing hydrological data. In this context, the use of monitoring systems by remote sensing is a good option. In this study, we simulated filling and drainage processes of an Amazon floodplain (Janauacá Lake, AM, Brazil) over a 6 years period (2006-2012). Common approaches of flow modeling in the Amazon region consist of coupling a 1D simulation of the main channel flood wave to a 2D simulation of the inundation of the floodplain. Here, our approach differs as the floodplain is fully simulated. Model used is the 3D model IPH-ECO, which consists of a three-dimensional hydrodynamic module coupled with an ecosystem module. The IPH-ECO hydrodynamic module solves the Reynolds-Averaged Navier-Stokes equations using a semi-implicit discretization. After having calibrated the simulation against roughness coefficients, we validated the model in terms of vertical accuracy against water levels (daily in situ and altimetrics data), in terms of flood extent against inundation maps deduced from available remote-sensed product imagery (ALOS-1/PALSAR.), and in terms of velocity. We analyzed the inter-annual variability in hydrological fluxes and inundation dynamics of the floodplain unit. Dominant sources of inflow varied seasonally: among direct rain and local runoff (November to April), Amazon River (May to August) and seepage (September to October).

Interaction of the Global Energy and Water Cycle Experiment (GEWEX) Water Resources Applications Project (WRAP) and Coordinated Enhanced Observing Project (CEOP) in Support of Water Resource Management and Planning

NASA Astrophysics Data System (ADS)

Martz, L.

2004-05-01

The Water Resources Applications Project (WRAP) has been developed within the Global Energy and Water Cycle Experiment (GEWEX) to facilitate the testing of GEWEX products and their transfer to operational water managers. The WRAP activity builds upon projects within the GEWEX Continental Scale Experiments (CSEs), and facilitates dialogue between these CSEs and their local water management communities regarding their information needs and opportunities for GEWEX products to meet those needs. Participating Continental Scale Experiments are located in the United States, the Mackenzie River Basin in Canada, the Amazon River Basin in Brazil, the Baltic Sea drainage area, eastern Asia and the Murray-Darling Basin in Australia. In addition, the development of WRAP is facilitating the transfer of techniques and demonstration projects to other areas through collaboration with IAHS, UNESCO/WMO HELP, WMO Hydrology and WWAP. The initiation of CEOP presents a significant new opportunity for collaborations to support the application of global hydro-climatological scientific data and techniques to water resource management. Some important scientific and operational issues identified by water resource management professionals in earlier workshops will be reviewed, some scientific initiatives needed to address these issues will be presented, and some case study examples of the application of GEWEX knowledge to water resource problems will be presented. Against this background, the unique opportunities that CEOP provides to improve our use and management of water resources globally will be discussed.

Assessment of an improved hydrological loading model from space geodesy: case study in South America

NASA Astrophysics Data System (ADS)

Nicolas, Joëlle; Boy, Jean-Paul; Durand, Frédéric; Mémin, Anthony

2017-04-01

Loading effects are crustal deformations induced by ocean, atmosphere and continental water mass redistributions. In this study we focus on hydrological loading effect monitored by space geodesy and in particular by GNSS and GRACE. Classically, hydrological loading models take into account snow and soil-moisture but don't consider surface waters (rivers, lakes…). As a result, huge discrepancies between GPS observations and those models arise around large rivers such as the Amazon where nearly half of the vertical signal cannot be explained by the combination of atmospheric, oceanic and hydrological loading models. To better resolve the hydrological signal, we improve the continental water storage models computed from soil-moisture and snow GLDAS/Noah or MERRA data sets by including surface water runoff. We investigate how continental water storage model improvements are supported by GNSS and GRACE observations in South America main river basins: Amazon, Orinoco and Parana. In this area the hydrological effects are among the largest in the world mainly due to the river level variations. We present the results of time series analyses with spectral and principal component analysis (PCA) methods. We extract the dominant spatio-temporal annual mode. We also identify and characterize the spatio-temporal changes in the annual hydrology signal, which is the key to a better understanding of the water cycle variations of those major rivers. We demonstrate that it is crucial to take into account the river contribution in fluid signatures before investigating high-frequency variability and episodic events.

The Fate of Amazonian Ecosystems over the Coming Century Arising from Changes in Climate, Atmospheric CO2 and Land-use

NASA Astrophysics Data System (ADS)

Moorcroft, P. R.; Zhang, K.; Castanho, A. D. D. A.; Galbraith, D.; Moghim, S.; Levine, N. M.; Bras, R. L.; Coe, M. T.; Costa, M. H.; Malhi, Y.; Longo, M.; Knox, R. G.; McKnight, S. L.; Wang, J.

2014-12-01

There is considerable interest and uncertainty regarding the expected fate of the Amazon over the coming century in face of the combined impacts of climate change, rising atmospheric CO2 levels, and on-going land transformation in the region. In this analysis, we explore the fate of Amazonian ecosystems under projected climate, CO2 and land-use change in the 21st century using three state-of-the-art terrestrial biosphere models (ED2, IBIS, and JULES) driven by three representative, bias-corrected GCM climate projections (PCM1, CCSM3, and HadCM3) under the SRES A2 scenario, coupled with two land-use change scenarios. We assess the relative roles of climate change, CO2 fertilization, land-use change, and fire in driving the projected changes in Amazonian biomass and forest extent. Our results indicate that the impacts of climate change depend strongly on the direction and severity of projected changes in precipitation regimes within the region: under the driest climate projection, climate change alone is predicted to reduce Amazonian forest cover by an average of 14%; however, the models predict that CO2 fertilization will enhance vegetation productivity and alleviate climate-induced increases in plant water stress, and as a result sustain high biomass forests, even under the driest climate scenario. Land-use change and changes in fire frequency are predicted cause additional aboveground live biomass loss and changes in forest extent. The relative impact of land-use and fire dynamics versus the impacts of climate and CO2 on the Amazon varies considerably, depending on both the climate and land-use scenarios used and on the terrestrial biosphere model, highlighting the importance of improved understanding of all four factors -- future climate, CO2 fertilization effects, fire and land-use -- to the fate of the Amazon over the coming century.

Boverhof's App Earns Honorable Mention in Amazon's Web Services

Science.gov Websites

» Boverhof's App Earns Honorable Mention in Amazon's Web Services Competition News & Publications News Publications Facebook Google+ Twitter Boverhof's App Earns Honorable Mention in Amazon's Web Services by Amazon Web Services (AWS). Amazon officially announced the winners of its EC2 Spotathon on Monday

A new species of Taosa (Hemiptera:Dictyopharide) from South America associated with Water Hyacinth

USDA-ARS?s Scientific Manuscript database

A new species of Taosa (Hemiptera: Dictyopharidae) is described. All the stages were collected on the aquatic weed Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae) at several localities on the Paraguay River in Argentina, and the upper Amazon River in Perú. Taosa impictifrons Remes Leni...

First ‘made in Brazil’ satellite to launch next year

NASA Astrophysics Data System (ADS)

Ivanissevich, Alicia

2017-06-01

Brazil has completed the construction of the country’s first satellite to be built entirely without international help. Amazônia-1, which is due to be launched next year, will image deforestation in the Amazon region as well as monitor agricultural areas, water reservoirs and coastal zones.

Envenomation by Micrurus coral snakes in the Brazilian Amazon region: report of two cases.

PubMed

Pardal, Pedro Pereira de Oliveira; Pardal, Joseana Silva de Oliveira; Gadelha, Maria Apolônia da Costa; Rodrigues, Líliam da Silva; Feitosa, Darlan Tavares; Prudente, Ana Lúcia da Costa; Fan, Hui Wen

2010-01-01

Two cases of proven coral snake bites were reported in Belém, Pará State, Brazil. The first case was a severe one caused by Micrurus surinamensis. The patient required mechanical ventilation due to acute respiratory failure. The second case showed just mild signs of envenomation caused by Micrurus filiformis. Both patients received specific Micrurus antivenom and were discharged without further complications. Coral snake bites are scarcely reported in the Amazon region and there is a broad spectrum of clinical manifestations, varying from extremely mild to those which may rapidly lead to death if the patient is not treated as soon as possible.

Human Dimensions of Deforestation and Regrowth in the Brazilian Amazon: Integrating Data from Satellites, Demographic Censuses, and Field Surveys

NASA Technical Reports Server (NTRS)

Wood, Charles H.; Sanderson, Steven E.; Skole, David L.

2001-01-01

This report summarizes research activities and products from a collaborative project on the "Human Dimensions of Deforestation and Regrowth in the Brazilian Amazon," awarded to Charles H. Wood (PI; Department of Sociology, University of Texas at Austin, now in the Center for Latin American Studies, University of Florida), Steven E. Sanderson (Co-PI; Department of Political Science, University of Florida, now Dean of Emory College, Emory University) and David L. Skole (Co-PI; Institute for Earth, Oceans and Space, University of New Hampshire, now in the Department of Geography and Basic Science Remote Sensing Initiative, Michigan State University).

Confluence of the Amazon and Topajos Rivers, Brazil, South America

NASA Image and Video Library

1991-08-11

This view shows the confluence of the Amazon and the Topajos Rivers at Santarem, Brazil (2.0S, 55.0W). The Am,azon flows from lower left to upper right of the photo. Below the river juncture of the Amazon and Tapajos, there is considerable deforestation activity along the Trans-Amazon Highway.

An extensive reef system at the Amazon River mouth

PubMed Central

Moura, Rodrigo L.; Amado-Filho, Gilberto M.; Moraes, Fernando C.; Brasileiro, Poliana S.; Salomon, Paulo S.; Mahiques, Michel M.; Bastos, Alex C.; Almeida, Marcelo G.; Silva, Jomar M.; Araujo, Beatriz F.; Brito, Frederico P.; Rangel, Thiago P.; Oliveira, Braulio C. V.; Bahia, Ricardo G.; Paranhos, Rodolfo P.; Dias, Rodolfo J. S.; Siegle, Eduardo; Figueiredo, Alberto G.; Pereira, Renato C.; Leal, Camille V.; Hajdu, Eduardo; Asp, Nils E.; Gregoracci, Gustavo B.; Neumann-Leitão, Sigrid; Yager, Patricia L.; Francini-Filho, Ronaldo B.; Fróes, Adriana; Campeão, Mariana; Silva, Bruno S.; Moreira, Ana P. B.; Oliveira, Louisi; Soares, Ana C.; Araujo, Lais; Oliveira, Nara L.; Teixeira, João B.; Valle, Rogerio A. B.; Thompson, Cristiane C.; Rezende, Carlos E.; Thompson, Fabiano L.

2016-01-01

Large rivers create major gaps in reef distribution along tropical shelves. The Amazon River represents 20% of the global riverine discharge to the ocean, generating up to a 1.3 × 106–km2 plume, and extensive muddy bottoms in the equatorial margin of South America. As a result, a wide area of the tropical North Atlantic is heavily affected in terms of salinity, pH, light penetration, and sedimentation. Such unfavorable conditions were thought to imprint a major gap in Western Atlantic reefs. We present an extensive carbonate system off the Amazon mouth, underneath the river plume. Significant carbonate sedimentation occurred during lowstand sea level, and still occurs in the outer shelf, resulting in complex hard-bottom topography. A permanent near-bottom wedge of ocean water, together with the seasonal nature of the plume’s eastward retroflection, conditions the existence of this extensive (~9500 km2) hard-bottom mosaic. The Amazon reefs transition from accretive to erosional structures and encompass extensive rhodolith beds. Carbonate structures function as a connectivity corridor for wide depth–ranging reef-associated species, being heavily colonized by large sponges and other structure-forming filter feeders that dwell under low light and high levels of particulates. The oxycline between the plume and subplume is associated with chemoautotrophic and anaerobic microbial metabolisms. The system described here provides several insights about the responses of tropical reefs to suboptimal and marginal reef-building conditions, which are accelerating worldwide due to global changes. PMID:27152336

Soil carbon dynamics

NASA Astrophysics Data System (ADS)

Trumbore, Susan; Barbosa de Camargo, Plínio

The amount of organic carbon (C) stored in the upper meter of mineral soils in the Amazon Basin (˜40 Pg C) represents ˜3% of the estimated global store of soil carbon. Adding surface detrital C stocks and soil carbon deeper than 1 m can as much as quadruple this estimate. The potential for Amazon soil carbon to respond to changes in land use, climate, or atmospheric composition depends on the form and dynamics of soil carbon. Much (˜30% in the top ˜10 cm but >85% in soils to 1 m depth) of the carbon in mineral soils of the Oxisols and Ultisols that are the predominant soil types in the Amazon Basin is in forms that are strongly stabilized, with mean ages of centuries to thousands of years. Measurable changes in soil C stocks that accompany land use/land cover change occur in the upper meter of soil, although the presence of deep roots in forests systems drives an active C cycle at depths >1 m. Credible estimates of the potential for changes in Amazon soil C stocks with future land use and climate change are much smaller than predictions of aboveground biomass change. Soil organic matter influences fertility and other key soil properties, and thus is important independent of its role in the global C cycle. Most work on C dynamics is limited to upland soils, and more is needed to investigate C dynamics in poorly drained soils. Work is also needed to relate cycles of C with water, N, P, and other elements.

An extensive reef system at the Amazon River mouth.

PubMed

Moura, Rodrigo L; Amado-Filho, Gilberto M; Moraes, Fernando C; Brasileiro, Poliana S; Salomon, Paulo S; Mahiques, Michel M; Bastos, Alex C; Almeida, Marcelo G; Silva, Jomar M; Araujo, Beatriz F; Brito, Frederico P; Rangel, Thiago P; Oliveira, Braulio C V; Bahia, Ricardo G; Paranhos, Rodolfo P; Dias, Rodolfo J S; Siegle, Eduardo; Figueiredo, Alberto G; Pereira, Renato C; Leal, Camille V; Hajdu, Eduardo; Asp, Nils E; Gregoracci, Gustavo B; Neumann-Leitão, Sigrid; Yager, Patricia L; Francini-Filho, Ronaldo B; Fróes, Adriana; Campeão, Mariana; Silva, Bruno S; Moreira, Ana P B; Oliveira, Louisi; Soares, Ana C; Araujo, Lais; Oliveira, Nara L; Teixeira, João B; Valle, Rogerio A B; Thompson, Cristiane C; Rezende, Carlos E; Thompson, Fabiano L

2016-04-01

Large rivers create major gaps in reef distribution along tropical shelves. The Amazon River represents 20% of the global riverine discharge to the ocean, generating up to a 1.3 × 10(6)-km(2) plume, and extensive muddy bottoms in the equatorial margin of South America. As a result, a wide area of the tropical North Atlantic is heavily affected in terms of salinity, pH, light penetration, and sedimentation. Such unfavorable conditions were thought to imprint a major gap in Western Atlantic reefs. We present an extensive carbonate system off the Amazon mouth, underneath the river plume. Significant carbonate sedimentation occurred during lowstand sea level, and still occurs in the outer shelf, resulting in complex hard-bottom topography. A permanent near-bottom wedge of ocean water, together with the seasonal nature of the plume's eastward retroflection, conditions the existence of this extensive (~9500 km(2)) hard-bottom mosaic. The Amazon reefs transition from accretive to erosional structures and encompass extensive rhodolith beds. Carbonate structures function as a connectivity corridor for wide depth-ranging reef-associated species, being heavily colonized by large sponges and other structure-forming filter feeders that dwell under low light and high levels of particulates. The oxycline between the plume and subplume is associated with chemoautotrophic and anaerobic microbial metabolisms. The system described here provides several insights about the responses of tropical reefs to suboptimal and marginal reef-building conditions, which are accelerating worldwide due to global changes.

Recent variations in Amazon carbon balance driven by climate anomalies

NASA Astrophysics Data System (ADS)

Miller, J. B.

2015-12-01

Understanding tropical rainforest response to heat and drought is critical for quantifying the effects of climate change on tropical ecosystems, including global climate-carbon feedbacks. Of particular importance for the global carbon budget is net ecosystem exchange of CO2 with the atmosphere (NEE), a metric that represents the total integrated signal of carbon fluxes into and out of ecosystems. Sub-annual and sub-basin NEE estimates have previously been derived from process-based biosphere models, despite often disagreeing with plot-scale observations. Our analysis of airborne CO2 and CO measurements reveals monthly, sub-Basin scale (~106 km2) NEE variations in a framework that is largely independent of bottom-up estimates. As such, our approach provides new insights about tropical forest response to climate. We find acute sensitivity of NEE to daily and monthly climate extremes. In particular, increased central-Amazon NEE was associated with wet-season heat and dry-season drought in 2010. We analyze satellite proxies for photosynthesis and find that suppression of photosynthesis may have contributed to increased carbon loss in the 2010 drought, consistent with recent analysis of plot-scale measurements. In the eastern Amazon, pulses of increased NEE (i.e. net respiration) persisted through 2011, suggesting legacy effects of the drought that occurred in 2010. Regional differences in post-drought recovery in 2011 and 2012 appear related to long-term water availability. These results provide novel evidence of the vulnerability of Amazon carbon stocks to short-term temperature and moisture extremes.

Occurrence of velogenic viscerotropic Newcastle disease in pet and exotic birds in 1991.

PubMed

Panigrahy, B; Senne, D A; Pearson, J E; Mixson, M A; Cassidy, D R

1993-01-01

In 1991, velogenic viscerotropic Newcastle disease (VVND) was diagnosed in domestic psittacine birds in six states: Illinois, Indiana, Michigan, Texas, California, and Nevada. In the first four states, the disease assumed outbreak proportions. The affected psittacine birds--yellow-headed Amazon parrots (Amazona ochrocephala oratrix), yellow-naped Amazon parrots (Amazona ochrocephala auropalliata), cockatiels (Nymphicus hollandicus), and conures (unknown species)--exhibited respiratory and/or central nervous system signs. The velogenic viscerotropic Newcastle disease virus (VVNDV) was isolated from cloacal and tracheal swabs and various tissues, such as the lung, trachea, distal intestine, and spleen. The origin of the birds could not be established. The disease in the six states was promptly controlled, with no evidence that domestic poultry had been exposed. Also, VVNDV was isolated from quarantined birds intended for importation into the United States. Included were 53 moustached parakeets (Psittacula alexandri fasciata), a mynah (Gracula religiosa), a drongo (Dicrurus sp.), and three partridges (family Phasianidae). Groups of birds that yielded VVNDV were denied entry into the United States. Birds that are illegally imported and therefore not tested for the presence of foreign animal pathogens are a potential source of VVNDV and a threat to domestic poultry and caged birds.

Integrating Marine Observatories into a System-of-Systems: Messaging in the US Ocean Observatories Initiative

DTIC Science & Technology

2010-06-01

Woods Hole, MA 02543, USA 3 Raytheon Intelligence and Information Systems, Aurora , CO 80011, USA 4 Scripps Institution of Oceanography, La Jolla...Amazon.com, Amazon Web Services for the Amazon Elastic Compute Cloud ( Amazon EC2). http://aws.amazon.com/ec2/. [4] M. Arrott, B. Demchak, V. Ermagan, C

Socioeconomic and Health Profile of Haitian Immigrants in a Brazilian Amazon State.

PubMed

Borges, Fabiano Tonaco; Muraro, Ana Paula; da Costa Leão, Luís Henrique; de Andrade Carvalho, Luciana; Siqueira, Carlos Eduardo Gomes

2018-01-25

We analyzed the sociodemographic profile, migration journey, health conditions, and health care access and utilization among recent Haitian immigrants to the Brazilian Amazon state of Mato Grosso. We conducted a cross-sectional study with a probabilistic sample of 452 Haitians. We administered a bilingual questionnaire from December 2014 to February 2015. Data were analyzed using chi square tests to evaluate differences among groups. The majority of participants were married men younger than 35 years old. They mostly came from the Haiti's Artibonite Department, living in Brazil for less than a year. Half of the participants were employed at the time of the interviews, and 81.8% relied exclusively on the Brazilian Unified Healthcare System for medical care. The overall health profile and health care access were good. Haitian migration to Brasil is a case of South-South migration driven by economic needs. Our population had good health status despite socioeconomic challenges.

Yellow fever in Pará State, Amazon region of Brazil, 1998-1999: entomologic and epidemiologic findings.

PubMed

Vasconcelos, P F; Rosa, A P; Rodrigues, S G; Rosa, E S; Monteiro, H A; Cruz, A C; Barros, V L; Souza, M R; Rosa, J F

2001-01-01

Yellow fever (YF) is frequently associated with high severity and death rates in the Amazon region of Brazil. During the rainy seasons of 1998 and 1999, 23 (eight deaths) and 34 (eight deaths) human cases of YF were reported, respectively, in different geographic areas of Pará State; most cases were on Marajó Island. Patients were 1 to 46 years of age. Epidemiologic and ecological studies were conducted in Afuá and Breves on Marajó Island; captured insects yielded isolates of 4 and 11 YF strains, respectively, from Haemagogus janthinomys pooled mosquitoes. The cases on Marajó Island in 1999 resulted from lack of vaccination near the focus of the disease and intense migration, which brought many nonimmune people to areas where infected vectors were present. We hypothesize that YF virus remains in an area after an outbreak by vertical transmission among Haemagogus mosquitoes.

Evidence of new species for malaria vector Anopheles nuneztovari sensu lato in the Brazilian Amazon region.

PubMed

Scarpassa, Vera Margarete; Cunha-Machado, Antonio Saulo; Saraiva, José Ferreira

2016-04-12

Anopheles nuneztovari sensu lato comprises cryptic species in northern South America, and the Brazilian populations encompass distinct genetic lineages within the Brazilian Amazon region. This study investigated, based on two molecular markers, whether these lineages might actually deserve species status. Specimens were collected in five localities of the Brazilian Amazon, including Manaus, Careiro Castanho and Autazes, in the State of Amazonas; Tucuruí, in the State of Pará; and Abacate da Pedreira, in the State of Amapá, and analysed for the COI gene (Barcode region) and 12 microsatellite loci. Phylogenetic analyses were performed using the maximum likelihood (ML) approach. Intra and inter samples genetic diversity were estimated using population genetics analyses, and the genetic groups were identified by means of the ML, Bayesian and factorial correspondence analyses and the Bayesian analysis of population structure. The Barcode region dataset (N = 103) generated 27 haplotypes. The haplotype network suggested three lineages. The ML tree retrieved five monophyletic groups. Group I clustered all specimens from Manaus and Careiro Castanho, the majority of Autazes and a few from Abacate da Pedreira. Group II clustered most of the specimens from Abacate da Pedreira and a few from Autazes and Tucuruí. Group III clustered only specimens from Tucuruí (lineage III), strongly supported (97 %). Groups IV and V clustered specimens of A. nuneztovari s.s. and A. dunhami, strongly (98 %) and weakly (70 %) supported, respectively. In the second phylogenetic analysis, the sequences from GenBank, identified as A. goeldii, clustered to groups I and II, but not to group III. Genetic distances (Kimura-2 parameters) among the groups ranged from 1.60 % (between I and II) to 2.32 % (between I and III). Microsatellite data revealed very high intra-population genetic variability. Genetic distances showed the highest and significant values (P = 0.005) between Tucuruí and all the other samples, and between Abacate da Pedreira and all the other samples. Genetic distances, Bayesian (Structure and BAPS) analyses and FCA suggested three distinct biological groups, supporting the barcode region results. The two markers revealed three genetic lineages for A. nuneztovari s.l. in the Brazilian Amazon region. Lineages I and II may represent genetically distinct groups or species within A. goeldii. Lineage III may represent a new species, distinct from the A. goeldii group, and may be the most ancestral in the Brazilian Amazon. They may have differences in Plasmodium susceptibility and should therefore be investigated further.

Decoupling of Deforestation and Soy Production in the Southern Amazon During the Late 2000s

NASA Technical Reports Server (NTRS)

Macedo, Marcia N.; DeFries, Ruth S.; Morton, Douglas C.; Stickler, Claudia M.; Galford, Gillian L.; Shimabukuro, Yosio E.

2011-01-01

From 2006-2010 deforestation in the Amazon frontier state of Mato Grosso decreased to 30% of its historical average (1996-2005) while agricultural production reached an all time high, achieving the oft-cited objective of increasing production while maintaining forest cover. This study combines satellite data with government deforestation and production statistics to assess land-use transitions and potential market and policy drivers associated with these trends. In the forested region of the state, increased soy production from 2001-2005 was entirely due to cropland expansion into previously cleared areas (74%) or forests (26%). From 2006-2010, 78% of production increases were due to expansion (22% to yield increases), with 91% on previously cleared land. Cropland expansion fell from 10% to 2% of deforestation between the two periods, with pasture expansion accounting for most remaining deforestation. Declining deforestation coincided with a collapse of commodity markets and implementation of policy measures to reduce deforestation. Soybean profitability has since increased to pre-2006 levels while deforestation continued to decline, suggesting that anti-deforestation measures may have influenced the agricultural sector. We found little evidence of leakage of soy expansion into cerrado in Mato Grosso or forests in neighboring Amazon states during the late 2000s, although leakage to more distant regions is possible. This study provides empirical evidence that reduced deforestation and increased agricultural production can occur simultaneously in tropical forest frontiers through productive use of already cleared lands. It remains uncertain whether government and industry-led policies can contain deforestation when market conditions again favor a boom in agricultural expansion.

[Research Programs Conducted by the University of Virginia]. Part 1; Aquarius

NASA Technical Reports Server (NTRS)

Fuentes, Jose; Garstang, Michael; Macko, Stephen; Swap, Robert

2001-01-01

The hydrological cycle and the source of water vapor within the Amazon River Basin have important implications on questions of global thermal transport and regional ecological and socioeconomic sustainability. A three tiered approach taking advantage of satellite imagery, tipping buckets, and isotopic storm sampling at three basin sites was used to examine different aspects of regional meteoric water. By combining these techniques, it was possible to correlate observed storm structure with rain rates and intrastorm variations.

Global Terrestrial Water Storage Changes and Connections to ENSO Events

NASA Astrophysics Data System (ADS)

Ni, Shengnan; Chen, Jianli; Wilson, Clark R.; Li, Jin; Hu, Xiaogong; Fu, Rong

2018-01-01

Improved data quality of extended record of the Gravity Recovery and Climate Experiment (GRACE) satellite gravity solutions enables better understanding of terrestrial water storage (TWS) variations. Connections of TWS and climate change are critical to investigate regional and global water cycles. In this study, we provide a comprehensive analysis of global connections between interannual TWS changes and El Niño Southern Oscillation (ENSO) events, using multiple sources of data, including GRACE measurements, land surface model (LSM) predictions and precipitation observations. We use cross-correlation and coherence spectrum analysis to examine global connections between interannual TWS changes and the Niño 3.4 index, and select four river basins (Amazon, Orinoco, Colorado, and Lena) for more detailed analysis. The results indicate that interannual TWS changes are strongly correlated with ENSO over much of the globe, with maximum cross-correlation coefficients up to 0.70, well above the 95% significance level ( 0.29) derived by the Monte Carlo experiments. The strongest correlations are found in tropical and subtropical regions, especially in the Amazon, Orinoco, and La Plata basins. While both GRACE and LSM TWS estimates show reasonably good correlations with ENSO and generally consistent spatial correlation patterns, notably higher correlations are found between GRACE TWS and ENSO. The existence of significant correlations in middle-high latitudes shows the large-scale impact of ENSO on the global water cycle.

Short term effects of fire on soil respiration in Peruvian Amazon

NASA Astrophysics Data System (ADS)

Suarez, L. F.; Kruijt, B.

2008-05-01

Severe changes are affecting the role of Amazon in the Earth system. One of these possible effects could be the modification of the role of soils in the carbon cycle due to land use and land cover change activities mainly involving the change of forest by crops. In this sense, fire is the main tool used by farmers for land use and also is an important factor for mobilizing C from the soil to the atmosphere, mainly as CO2. This could have an important effect in the global warming. This proposal will evaluate the variation of the soil respiration related to the seasonality and the fire effects on soils in the Amazon of Peru and Brazil. In experimental locations of Peru with different vegetation cover (forest and pasture), we measured soil respiration along with the organic carbon and the microbial biomass of soils during campaigns covering wet and dry seasons. Complementary measurements of soil temperature, water and nutrient content were performed. Also, we reproduced a fire experiment simulating agricultural local activity by the technique of "slash and burn" to evaluate fire effects on soil respiration. Measurements were taken after the soil cooled and at least 3 days after the fire. Additionally, the carbon stocks of the subplots were evaluated. Evaluation of the variations of CO2 fluxes and the capacity of adaptation to fire and water content are discussed through the comparisons of the different locations, type of soils and concentration of available N (nitrate and ammonium) as an indicator of nutrient content.

IAI Global Change Agenda and Support of Higher Education in the Andean Amazon Countries.

NASA Astrophysics Data System (ADS)

Galarraga, R.; McClain, M.; Fierro, V.

2007-05-01

The Andean Amazon River Analysis and Management project, an IAI Collaborative Research Network operating during 1999-2004, examined the impacts of climate and land-use changes on the hydrobiogeochemistry of rivers draining the Amazon Andes of Ecuador, Peru, Colombia and Bolivia. The project also provided a means to strengthen scientific collaboration among these Andean countries and the USA. Research in these countries was carried out under the guidance of investigators with backgrounds in the relevant environmental fields, but the bulk of the research activities were carried out by undergraduate and graduate students who studied within these countries and overseas. Twenty graduate students and 15 undergraduates completed studies within the project, in topics related to monitoring hydrometeorological variables both in time and space. Student research and capacity building were focused in areas central to global environmental change, including modeling of precipitation and precipitation-runoff processes, basin-scale water quality characterization and biogeochemical cycling, and socioeconomic controls on the use and management of riverine resources. The analysis of human dimension aspects of climate change research was also featured, especially those aspects that linked the consequences of water quality degradation on human health. Most of undergraduate and graduate students that collaborated in the AARAM project have joined national environmental institutions and some have continued for higher scientific degrees in fields closely related to the IAI scientific agenda. Through this IAI initiative, the number of trained global change scientists in the Andean countries has grown and there is enhanced awareness of key global change science issues among the scientific community.

Fog and rain in the Amazon

PubMed Central

Anber, Usama; Gentine, Pierre; Wang, Shuguang; Sobel, Adam H.

2015-01-01

The diurnal and seasonal water cycles in the Amazon remain poorly simulated in general circulation models, exhibiting peak evapotranspiration in the wrong season and rain too early in the day. We show that those biases are not present in cloud-resolving simulations with parameterized large-scale circulation. The difference is attributed to the representation of the morning fog layer, and to more accurate characterization of convection and its coupling with large-scale circulation. The morning fog layer, present in the wet season but absent in the dry season, dramatically increases cloud albedo, which reduces evapotranspiration through its modulation of the surface energy budget. These results highlight the importance of the coupling between the energy and hydrological cycles and the key role of cloud albedo feedback for climates over tropical continents. PMID:26324902

Fog and rain in the Amazon

DOE PAGES

Anber, Usama; Gentine, Pierre; Wang, Shuguang; ...

2015-08-31

The diurnal and seasonal water cycles in the Amazon remain poorly simulated in general circulation models, exhibiting peak evapotranspiration in the wrong season and rain too early in the day. We show that those biases are not present in cloud-resolving simulations with parameterized large-scale circulation. The difference is attributed to the representation of the morning fog layer, and to more accurate characterization of convection and its coupling with large-scale circulation. The morning fog layer, present in the wet season but absent in the dry season, dramatically increases cloud albedo, which reduces evapotranspiration through its modulation of the surface energy budget.more » Finally, these results highlight the importance of the coupling between the energy and hydrological cycles and the key role of cloud albedo feedback for climates over tropical continents.« less

Ongoing River Capture in the Amazon via Secondary Channel Flow

NASA Astrophysics Data System (ADS)

Goldberg, S. L.; Stokes, M.; Perron, J. T.

2017-12-01

The Rio Casiquiare in South America is a secondary channel that originates as a distributary of the Rio Orinoco and flows into the Rio Negro as a tributary to form a perennial connection between the Amazon and Orinoco basins, the largest and fourth-largest rivers on Earth by discharge. This unusual configuration is the result of an incomplete and ongoing river capture in which the Rio Negro is actively capturing the upper Rio Orinoco. This rarely observed intermediate stage of capture illuminates important mechanisms that drive river capture in lowland settings, both in the Amazon basin and elsewhere. In particular, we show that the capture of the Rio Orinoco by the Rio Casiquiare is driven by a combination of headward incision of a rapidly eroding tributary of the Rio Negro, sedimentation in the Rio Orinoco downstream of the bifurcation, and seasonal inundation of a low-relief divide. The initiation of the bifurcation by headward erosion caused an increase in discharge to the Rio Casiquiare while the corresponding loss of discharge to the downstream Rio Orinoco has led to observable sedimentation within the main channel. Unlike most ephemeral secondary channels, the Rio Casiquiare appears to be growing, suggesting that the present bifurcation is an unstable feature that will eventually lead to the complete capture of the upper Rio Orinoco by the Rio Casiquiare. This capture is the latest major event in the late Cenozoic drainage evolution of South America in response to Andean tectonism, and is an example of the lateral expansion of the Amazon basin through river capture following integration and entrenchment of the transcontinental Amazon River. The Rio Casiquiare provides a snapshot of an intermediate, transient state of bifurcation and inter-basin flow via a secondary channel during lowland river capture.

77 FR 24518 - United States v. Apple, Inc., Hachette Book Group, Inc., HarperCollins Publishers L.L.C...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-24

... dining rooms of upscale Manhattan restaurants and were used to discuss confidential business and... different Manhattan restaurant, Alto. They discussed the growth of e-books and complained about Amazon's...

Novel Henneguya spp. (Cnidaria: Myxozoa) from cichlid fish in the Amazon basin cluster by geographic origin.

PubMed

Zatti, Suellen Aparecida; Atkinson, Stephen D; Maia, Antônio A M; Bartholomew, Jerri L; Adriano, Edson A

2018-03-01

We describe three new Henneguya spp. (Myxobolidae) found parasitizing two species of cichlid fish from the Amazon basin, Brazil: H. tucunarei n. sp. from gill filaments of Cichla monoculus and H. tapajoensis n. sp. from gill filaments of Cichla pinima, both from the Tapajós River, Pará State and H. jariensis n. sp. in the fins of Cichla monoculus from the Jari River, Amapá State. We based descriptions on myxospore morphology and small subunit ribosomal DNA sequences, and used a phylogenetic analysis to compare the new Henneguya species with known relatives. Spores of the three species had similar morphology and morphometrics, but differed molecularly 5-7.5%, and were no more than 94% similar to any other sequence in GenBank. Together with having different hosts, these data supported the diagnosis of the parasites as distinct, novel species. Maximum likelihood and Bayesian analyses showed that H. tucunarei n. sp., H. tapajoensis n. sp., and H. jariensis n. sp. plus Henneguya paraensis (which parasitizes Cichla temensis) formed a well-supported sub-clade of Henneguya parasites of cichlids from the Amazon basin, in a lineage sister to those in characiforms hosts. Our analysis was consistent with previous studies that suggest that aquatic environment and vertebrate host group are the strongest correlates with phylogenetic signals in the Myxobolidae.

[Association between particulate matter from biomass burning and respiratory diseases in the southern region of the Brazilian Amazon].

PubMed

do Carmo, Cleber Nascimento; Hacon, Sandra; Longo, Karla Maria; Freitas, Saulo; Ignotti, Eliane; Ponce de Leon, Antonio; Artaxo, Paulo

2010-01-01

To investigate the short-term effects of exposure to particulate matter from biomass burning in the Amazon on the daily demand for outpatient care due to respiratory diseases in children and the elderly. Epidemiologic study with ecologic time series design. Daily consultation records were obtained from the 14 primary health care clinics in the municipality of Alta Floresta, state of Mato Grosso, in the southern region of the Brazilian Amazon, between January 2004 and December 2005. Information on the daily levels of fine particulate matter was made available by the Brazilian National Institute for Spatial Research. To control for confounding factors (situations in which a non-causal association between exposure and disease is observed due to a third variable), variables related to time trends, seasonality, temperature, relative humidity, rainfall, and calendar effects (such as occurrence of holidays and weekends) were included in the model. Poisson regression with generalized additive models was used. A 10 microg/m3 increase in the level of exposure to particulate matter was associated with increases of 2.9% and 2.6% in outpatient consultations due to respiratory diseases in children on the 6th and 7th days following exposure. Significant associations were not observed for elderly individuals. The results suggest that the levels of particulate matter from biomass burning in the Amazon are associated with adverse effects on the respiratory health of children.

Conservation performance of different conservation governance regimes in the Peruvian Amazon.

PubMed

Schleicher, Judith; Peres, Carlos A; Amano, Tatsuya; Llactayo, William; Leader-Williams, Nigel

2017-09-12

State-controlled protected areas (PAs) have dominated conservation strategies globally, yet their performance relative to other governance regimes is rarely assessed comprehensively. Furthermore, performance indicators of forest PAs are typically restricted to deforestation, although the extent of forest degradation is greater. We address these shortfalls through an empirical impact evaluation of state PAs, Indigenous Territories (ITs), and civil society and private Conservation Concessions (CCs) on deforestation and degradation throughout the Peruvian Amazon. We integrated remote-sensing data with environmental and socio-economic datasets, and used propensity-score matching to assess: (i) how deforestation and degradation varied across governance regimes between 2006-2011; (ii) their proximate drivers; and (iii) whether state PAs, CCs and ITs avoided deforestation and degradation compared with logging and mining concessions, and the unprotected landscape. CCs, state PAs, and ITs all avoided deforestation and degradation compared to analogous areas in the unprotected landscape. CCs and ITs were on average more effective in this respect than state PAs, showing that local governance can be equally or more effective than centralized state regimes. However, there were no consistent differences between conservation governance regimes when matched to logging and mining concessions. Future impact assessments would therefore benefit from further disentangling governance regimes across unprotected land.

An Appalachian Amazon? Magnetofossil evidence for the development of a tropical river-like system in the mid-Atlantic United States during the Paleocene-Eocene Thermal Maximum

NASA Astrophysics Data System (ADS)

Kopp, R. E.; Schumann, D.; Raub, T. D.; Powars, D. S.; Godfrey, L. V.; Swanson-Hysell, N.; Maloof, A. C.; Vali, H.

2009-12-01

The Paleocene-Eocene Thermal Maximum is preserved within the mid-Atlantic Coastal Plain as a unique clay deposited in the Salisbury Embayment, a tectonic downwarp that stretches from southeastern Virginia to central New Jersey. The mostly massive and kaolinite-rich clay is distinct from the glauconitic sediments that otherwise characterize regional Paleocene and lower Eocene deposits. It contains abundant magnetite produced by magnetotactic bacteria and by larger, presumptively eukaryotic microorganisms not yet known from any other locality. Because most magnetotactic bacteria live within a specific, narrow redox environment -- the suboxic zone of a water column or sediments, where both oxygen and sulfide concentrations are low and iron concentrations relatively high -- their biominerals can be used as a paleoenvironmental tracer. High iron bioavailability indicates a relatively thick suboxic zone. The preservation of iron biominerals suggests that this zone was located in sediments, rather than in the water column, as water column suboxia is associated with high sedimentary organic carbon concentrations, which promote magnetite dissolution. The thickest modern, sedimentary, high-iron suboxic zones occur in tropical river-dominated shelves, such as the Amazon Shelf. These zones result from the combination of a moderately high input of reactive Fe (produced by tropical weathering conditions) with a high-energy environment (produced by tides, frontal-zone currents, and surface waves) that promotes the regular physical reworking of the sediments, thus allowing the re-oxidation of reduced Fe and increasing the availability of Fe as an electron acceptor. To test the "Appalachian Amazon" hypothesis, we mapped the distribution of magnetofossils throughout the Salisbury Embayment using ferromagnetic resonance spectroscopy and electron microscopy, supplemented by organic carbon isotope data. We find three magnetic facies in the clay: Facies 1, characterized by a mix of detrital particles and magnetofossils; Facies 2, with a higher magnetofossil-to-detrital ratio; and Facies 3, with only transient magnetofossils. Facies 1 occurs in inner-middle neritic deposits of central Maryland and northern Virginia, near where the modern Potomac crosses the Fall Line. Facies 2 occurs throughout the middle neritic deposits of eastern Maryland and Virginia and of southern New Jersey. Facies 3 occurs in the outer neritic deposits of eastern New Jersey and on the northern and southern flanks of the embayment. Consistent with the hypothesis, this distribution suggests a link between the magnetofossil distribution and a river system with an outlet in the vicinity of Facies 1. The development of such a river system may have been linked to a combination of more intense weathering, higher precipitation, and increased storminess.

Epidemiology and Control of Child Toxocariasis in the Western Brazilian Amazon – A Population-Based Study

PubMed Central

Oliart-Guzmán, Humberto; Delfino, Breno M.; Martins, Antonio C.; Mantovani, Saulo A. S.; Braña, Athos M.; Pereira, Thasciany M.; Branco, Fernando L. C. C.; Ramalho, Alanderson A.; Campos, Rhanderson G.; Fontoura, Pablo S.; de Araujo, Thiago S.; de Oliveira, Cristieli S. M.; Muniz, Pascoal T.; Rubinsky-Elefant, Guita; Codeço, Cláudia T.; da Silva-Nunes, Mônica

2014-01-01

Toxocara spp. infection and the seroconversion rate in the Amazon have been poorly investigated. This study analyzed individual and household-level risk factors for the presence of IgG antibodies to Toxocara spp. in urban Amazonian children over a period of 7 years and evaluated the seroconversion rates over a 1-year follow-up. In children < 59 months of age, the overall prevalence rate was 28.08% in 2003 and 23.35% in 2010. The 2010–2011 seroconversion rates were 13.90% for children 6–59 months of age and 12.30% for children 84–143 months of age. Multilevel logistic regression analysis identified child age, previous wheezing, and current infection with hookworm as significant associated factors for Toxocara spp. seropositivity in 2003. In 2010, age, previous helminthiasis, and having a dog were associated with seropositivity, whereas having piped water inside the household was a protective factor. Control programs mainly need to target at-risk children, water quality control, and animal deworming strategies. PMID:24515946

Interactions of Vegetation and Climate: Remote Observations, Earth System Models, and the Amazon Forest

NASA Astrophysics Data System (ADS)

Quetin, Gregory R.

The natural composition of terrestrial ecosystems can be shaped by climate to take advantage of local environmental conditions. Ecosystem functioning, e.g. interaction between photosynthesis and temperature, can also acclimate to different climatological states. The combination of these two factors thus determines ecological-climate interactions. The ecosystem functioning also plays a key role in predicting the carbon cycle, hydrological cycle, terrestrial surface energy balance, and the feedbacks in the climate system. Predicting the response of the Earth's biosphere to global warming requires the ability to mechanistically represent the processes controlling ecosystem functioning through photosynthesis, respiration, and water use. The physical environment in a place shapes the vegetation there, but vegetation also has the potential to shape the environment, e.g. increased photosynthesis and transpiration moisten the atmosphere. These two-way ecoclimate interactions create the potential for feedbacks between vegetation at the physical environment that depend on the vegetation and the climate of a place, and can change throughout the year. In Chapter 1, we derive a global empirical map of the sensitivity of vegetation to climate using the response of satellite-observed greenness to interannual variations in temperature and precipitation. We infer mechanisms constraining ecosystem functioning by analyzing how the sensitivity of vegetation to climate varies across climate space. Our analysis yields empirical evidence for multiple physical and biological mediators of the sensitivity of vegetation to climate at large spatial scales. In hot and wet locations, vegetation is greener in warmer years despite temperatures likely exceeding thermally optimum conditions. However, sunlight generally increases during warmer years, suggesting that the increased stress from higher atmospheric water demand is offset by higher rates of photosynthesis. The sensitivity of vegetation transitions in sign (greener when warmer or drier to greener when cooler or wetter) along an emergent line in climate space with a slope of about 59 mm/yr/°C, twice as steep as contours of aridity. The mismatch between these slopes is evidence at a global scale of the limitation of both water supply due to inefficiencies in plant access to rainfall, and plant physiological responses to atmospheric water demand. This empirical pattern can provide a functional constraint for process-based models, helping to improve predictions of the global-scale response of vegetation to a changing climate. In Chapter 2, we use observations of vegetation interaction with the physical environment to identify where ecosystem functioning is well simulated in an ensemble of Earth system models. We leverage this data-model comparison to hypothesize which physiological mechanisms--photosynthetic efficiency, respiration, water supply, atmospheric water demand, and sunlight availability--dominate the ecosystem response in places with different climates. The models are generally successful in reproducing the broad sign and shape of ecosystem function across climate space except for simulating generally lower leaf area during warmer years in places with hot wet climates. In addition, simulated ecosystem interaction with temperature is generally larger and changes more rapidly across a gradient of temperature than is observed. We hypothesize that the amplified interaction and change are both due to a lack of adaptation and acclimation in simulations. This discrepancy with observations suggests that simulated responses of vegetation to global warming, and feedbacks between vegetation and climate, are too strong in the models. Finally, models and observations share an abrupt threshold between dry regions and wet regions where strong positive vegetation response to precipitation falls to nearly zero in places receiving around 1000 mm/year. In Chapter 3, we investigate how ecoclimate interactions change across seasons in the Amazon basin. We use observations of solar induced fluorescence from the Orbiting Carbon Observatory 2 (OCO2) to statistically analyze the sensitivity of fluorescence to synoptic variations in temperature and precipitation. In addition to studying the sensitivity of vegetation to climate across seasons, we use OCO2 measurements of total column water vapor (TCWV) and CO2 concentration (XCO2) to investigate the influence of the Amazon basin vegetation on the CO2 concentration and water vapor of the atmosphere leaving the basin. Our analysis determines the seasonal importance of vegetation activity on the outflow of CO2 from the Amazon basin, while providing evidence that transpiration is primarily driven by variations in temperature during the dry season, rather than photosynthesis. We establish a statistical relationship between fluorescence (as a proxy for vegetation photosynthesis), temperature, and precipitation, as well as the difference between the outflow of atmospheric water vapor from the inflow water vapor, basin fluorescence, temperature, and precipitation.

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

NASA Astrophysics Data System (ADS)

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

2017-04-01

Amazon basin has experienced several intense droughts among which were highlighted last recent ones in 2005 and 2010. Climate models suggest these events will be even more frequent due to higher concentration of greenhouse gases that are also driven forward by alteration in forest dynamics. Environmental and social impacts demand to identify these intense droughts and the behavior of climate parameters that affect vegetation. This present study also identifies a recent intense drought in Amazon basin during 2015. Meteorological parameters and vegetation indices suggest this event was the most severe already registered in the region. We have used land surface temperature (LST), vegetation indices, rainfall and shortwave radiation from 2000 to 2015 to analyze and compare droughts of 2005, 2010 and 2015. Our results show singularities among the three climate extreme events. The austral winter was the most affected season in 2005 and 2010, but not in 2015 when austral summer presented extreme conditions. Precipitation indicates epicenter of 2005 in west Amazon corroborating with previous studies. In 2010, the west region was strongly affected again together with the northwest and the southeast areas. However, 2015 epicenters were concentrated in the east of the basin. In 2015, shortwave radiation has exceeded the maximum values of 2005 and temperature the maximum value of 2010. Vegetation indices have shown positive and negative anomalies. Despite of heterogenous response of Amazon forest to drought, hybrid vegetation indices using NDVI (Normalized Difference Vegetation Index) and LST highlights the exceptionality of 2015 drought episode that exhibits higher vegetation water stress than the cases of 2010 and 2005. Finally, this work has shown how meteorological parameters influence droughts and the effects on vegetation in Amazon basin. Complexity of climate, ecosystem heterogeneity and high diversity of Amazon forest are response by idiosyncrasies of each drought. All these information improve the predictability of future climate scenarios and their effects in the environment. Research performed was supported by FAPESP/FCT Project Brazilian Fire-Land-Atmosphere System (BrFLAS) (1389/2014 and 2015/01389-4), by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) through a Master grant from PPGM/IGEO/UFRJ (first author), and by Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) through grants E-26/201.521/2014; E-26/101.423/2014; E-26/201.221/2015; and E-26/203.174/2016.

Hydrogeological characterisation of groundwater over Brazil using remotely sensed and model products.

PubMed

Hu, Kexiang; Awange, Joseph L; Khandu; Forootan, Ehsan; Goncalves, Rodrigo Mikosz; Fleming, Kevin

2017-12-01

For Brazil, a country frequented by droughts and whose rural inhabitants largely depend on groundwater, reliance on isotope for its monitoring, though accurate, is expensive and limited in spatial coverage. We exploit total water storage (TWS) derived from Gravity Recovery and Climate Experiment (GRACE) satellites to analyse spatial-temporal groundwater changes in relation to geological characteristics. Large-scale groundwater changes are estimated using GRACE-derived TWS and altimetry observations in addition to GLDAS and WGHM model outputs. Additionally, TRMM precipitation data are used to infer impacts of climate variability on groundwater fluctuations. The results indicate that climate variability mainly controls groundwater change trends while geological properties control change rates, spatial distribution, and storage capacity. Granular rocks in the Amazon and Guarani aquifers are found to influence larger storage capability, higher permeability (>10 -4 m/s) and faster response to rainfall (1 to 3months' lag) compared to fractured rocks (permeability <10 -7 m/s and lags > 3months) found only in Bambui aquifer. Groundwater in the Amazon region is found to rely not only on precipitation but also on inflow from other regions. Areas beyond the northern and southern Amazon basin depict a 'dam-like' pattern, with high inflow and slow outflow rates (recharge slope > 0.75, discharge slope < 0.45). This is due to two impermeable rock layer-like 'walls' (permeability <10 -8 m/s) along the northern and southern Alter do Chão aquifer that help retain groundwater. The largest groundwater storage capacity in Brazil is the Amazon aquifer (with annual amplitudes of > 30cm). Amazon's groundwater declined between 2002 and 2008 due to below normal precipitation (wet seasons lasted for about 36 to 47% of the time). The Guarani aquifer and adjacent coastline areas rank second in terms of storage capacity, while the northeast and southeast coastal regions indicate the smallest storage capacity due to lack of rainfall (annual average is rainfall <10cm). Copyright © 2017 Elsevier B.V. All rights reserved.

Amazon rainforest responses to elevated CO2: Deriving model-based hypotheses for the AmazonFACE experiment

NASA Astrophysics Data System (ADS)

Rammig, A.; Fleischer, K.; Lapola, D.; Holm, J.; Hoosbeek, M.

2017-12-01

Increasing atmospheric CO2 concentration is assumed to have a stimulating effect ("CO2 fertilization effect") on forest growth and resilience. Empirical evidence, however, for the existence and strength of such a tropical CO2 fertilization effect is scarce and thus a major impediment for constraining the uncertainties in Earth System Model projections. The implications of the tropical CO2 effect are far-reaching, as it strongly influences the global carbon and water cycle, and hence future global climate. In the scope of the Amazon Free Air CO2 Enrichment (FACE) experiment, we addressed these uncertainties by assessing the CO2 fertilization effect at ecosystem scale. AmazonFACE is the first FACE experiment in an old-growth, highly diverse tropical rainforest. Here, we present a priori model-based hypotheses for the experiment derived from a set of 12 ecosystem models. Model simulations identified key uncertainties in our understanding of limiting processes and derived model-based hypotheses of expected ecosystem responses to elevated CO2 that can directly be tested during the experiment. Ambient model simulations compared satisfactorily with in-situ measurements of ecosystem carbon fluxes, as well as carbon, nitrogen, and phosphorus stocks. Models consistently predicted an increase in photosynthesis with elevated CO2, which declined over time due to developing limitations. The conversion of enhanced photosynthesis into biomass, and hence ecosystem carbon sequestration, varied strongly among the models due to different assumptions on nutrient limitation. Models with flexible allocation schemes consistently predicted an increased investment in belowground structures to alleviate nutrient limitation, in turn accelerating turnover rates of soil organic matter. The models diverged on the prediction for carbon accumulation after 10 years of elevated CO2, mainly due to contrasting assumptions in their phosphorus cycle representation. These differences define the expected response ratio to elevated CO2 at the AmazonFACE site and identify priorities for experimental work and model development.

Metagenome sequencing of the microbial community of two Brazilian anthropogenic Amazon dark earth sites, Brazil.

PubMed

Lemos, Leandro Nascimento; de Souza, Rosineide Cardoso; de Souza Cannavan, Fabiana; Patricio, André; Pylro, Victor Satler; Hanada, Rogério Eiji; Mui, Tsai Siu

2016-12-01

The Anthropogenic Amazon Dark Earth soil is considered one of the world's most fertile soils. These soils differs from conventional Amazon soils because its higher organic content concentration. Here we describe the metagenome sequencing of microbial communities of two sites of Anthropogenic Amazon Dark Earth soils from Amazon Rainforest, Brazil. The raw sequence data are stored under Short Read Accession number: PRJNA344917.

Virioplankton Assemblage Structure in the Lower River and Ocean Continuum of the Amazon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silva, Bruno S. de O.; Coutinho, Felipe H.; Gregoracci, Gustavo B.

ABSTRACT The Amazon River watershed and its associated plume comprise a vast continental and oceanic area. The microbial activities along this continuum contribute substantially to global carbon and nutrient cycling, and yet there is a dearth of information on the diversity, abundance, and possible roles of viruses in this globally important river. The aim of this study was to elucidate the diversity and structure of virus assemblages of the Amazon River-ocean continuum. Environmental viral DNA sequences were obtained for 12 locations along the river’s lower reach (n= 5) and plume (n= 7). Sequence assembly yielded 29,358 scaffolds, encoding 82,546 viralmore » proteins, with 15 new complete viral genomes. Despite the spatial connectivity mediated by the river, virome analyses and physical-chemical water parameters clearly distinguished river and plume ecosystems. Bacteriophages were ubiquitous in the continuum and were more abundant in the transition region. Eukaryotic viruses occurred mostly in the river, while the plume had more viruses of autotrophic organisms (Prochlorococcus,Synechococcus) and heterotrophic bacteria (Pelagibacter). The viral familiesMicroviridaeandMyoviridaewere the most abundant and occurred throughout the continuum. The major functions of the genes in the continuum involved viral structures and life cycles, and viruses from plume locations and Tapajós River showed the highest levels of functional diversity. The distribution patterns of the viral assemblages were defined not only by the occurrence of possible hosts but also by water physical and chemical parameters, especially salinity. The findings presented here help to improve understanding of the possible roles of viruses in the organic matter cycle along the river-ocean continuum. IMPORTANCEThe Amazon River forms a vast plume in the Atlantic Ocean that can extend for more than 1,000 km. Microbial communities promote a globally relevant carbon sink system in the plume. Despite the importance of viruses for the global carbon cycle, the diversity and the possible roles of viruses in the Amazon are poorly understood. The present work assesses, for the first time, the abundance and diversity of viruses simultaneously in the river and ocean in order to elucidate their possible roles. DNA sequence assembly yielded 29,358 scaffolds, encoding 82,546 viral proteins, with 15 new complete viral genomes from the 12 river and ocean locations. Viral diversity was clearly distinguished by river and ocean. Bacteriophages were the most abundant and occurred throughout the continuum. Viruses that infect eukaryotes were more abundant in the river, whereas phages appeared to have strong control over the host prokaryotic populations in the plume.« less

Virioplankton Assemblage Structure in the Lower River and Ocean Continuum of the Amazon.

PubMed

Silva, Bruno S de O; Coutinho, Felipe H; Gregoracci, Gustavo B; Leomil, Luciana; de Oliveira, Louisi S; Fróes, Adriana; Tschoeke, Diogo; Soares, Ana Carolina; Cabral, Anderson S; Ward, Nicholas D; Richey, Jeffrey E; Krusche, Alex V; Yager, Patricia L; de Rezende, Carlos Eduardo; Thompson, Cristiane C; Thompson, Fabiano L

2017-01-01

The Amazon River watershed and its associated plume comprise a vast continental and oceanic area. The microbial activities along this continuum contribute substantially to global carbon and nutrient cycling, and yet there is a dearth of information on the diversity, abundance, and possible roles of viruses in this globally important river. The aim of this study was to elucidate the diversity and structure of virus assemblages of the Amazon River-ocean continuum. Environmental viral DNA sequences were obtained for 12 locations along the river's lower reach ( n = 5) and plume ( n = 7). Sequence assembly yielded 29,358 scaffolds, encoding 82,546 viral proteins, with 15 new complete viral genomes. Despite the spatial connectivity mediated by the river, virome analyses and physical-chemical water parameters clearly distinguished river and plume ecosystems. Bacteriophages were ubiquitous in the continuum and were more abundant in the transition region. Eukaryotic viruses occurred mostly in the river, while the plume had more viruses of autotrophic organisms ( Prochlorococcus , Synechococcus ) and heterotrophic bacteria ( Pelagibacter ). The viral families Microviridae and Myoviridae were the most abundant and occurred throughout the continuum. The major functions of the genes in the continuum involved viral structures and life cycles, and viruses from plume locations and Tapajós River showed the highest levels of functional diversity. The distribution patterns of the viral assemblages were defined not only by the occurrence of possible hosts but also by water physical and chemical parameters, especially salinity. The findings presented here help to improve understanding of the possible roles of viruses in the organic matter cycle along the river-ocean continuum. IMPORTANCE The Amazon River forms a vast plume in the Atlantic Ocean that can extend for more than 1,000 km. Microbial communities promote a globally relevant carbon sink system in the plume. Despite the importance of viruses for the global carbon cycle, the diversity and the possible roles of viruses in the Amazon are poorly understood. The present work assesses, for the first time, the abundance and diversity of viruses simultaneously in the river and ocean in order to elucidate their possible roles. DNA sequence assembly yielded 29,358 scaffolds, encoding 82,546 viral proteins, with 15 new complete viral genomes from the 12 river and ocean locations. Viral diversity was clearly distinguished by river and ocean. Bacteriophages were the most abundant and occurred throughout the continuum. Viruses that infect eukaryotes were more abundant in the river, whereas phages appeared to have strong control over the host prokaryotic populations in the plume.

Virioplankton Assemblage Structure in the Lower River and Ocean Continuum of the Amazon

PubMed Central

Silva, Bruno S. de O.; Coutinho, Felipe H.; Gregoracci, Gustavo B.; Leomil, Luciana; de Oliveira, Louisi S.; Fróes, Adriana; Tschoeke, Diogo; Soares, Ana Carolina; Cabral, Anderson S.; Ward, Nicholas D.; Richey, Jeffrey E.; Krusche, Alex V.; Yager, Patricia L.; de Rezende, Carlos Eduardo; Thompson, Cristiane C.

2017-01-01

ABSTRACT The Amazon River watershed and its associated plume comprise a vast continental and oceanic area. The microbial activities along this continuum contribute substantially to global carbon and nutrient cycling, and yet there is a dearth of information on the diversity, abundance, and possible roles of viruses in this globally important river. The aim of this study was to elucidate the diversity and structure of virus assemblages of the Amazon River-ocean continuum. Environmental viral DNA sequences were obtained for 12 locations along the river’s lower reach (n = 5) and plume (n = 7). Sequence assembly yielded 29,358 scaffolds, encoding 82,546 viral proteins, with 15 new complete viral genomes. Despite the spatial connectivity mediated by the river, virome analyses and physical-chemical water parameters clearly distinguished river and plume ecosystems. Bacteriophages were ubiquitous in the continuum and were more abundant in the transition region. Eukaryotic viruses occurred mostly in the river, while the plume had more viruses of autotrophic organisms (Prochlorococcus, Synechococcus) and heterotrophic bacteria (Pelagibacter). The viral families Microviridae and Myoviridae were the most abundant and occurred throughout the continuum. The major functions of the genes in the continuum involved viral structures and life cycles, and viruses from plume locations and Tapajós River showed the highest levels of functional diversity. The distribution patterns of the viral assemblages were defined not only by the occurrence of possible hosts but also by water physical and chemical parameters, especially salinity. The findings presented here help to improve understanding of the possible roles of viruses in the organic matter cycle along the river-ocean continuum. IMPORTANCE The Amazon River forms a vast plume in the Atlantic Ocean that can extend for more than 1,000 km. Microbial communities promote a globally relevant carbon sink system in the plume. Despite the importance of viruses for the global carbon cycle, the diversity and the possible roles of viruses in the Amazon are poorly understood. The present work assesses, for the first time, the abundance and diversity of viruses simultaneously in the river and ocean in order to elucidate their possible roles. DNA sequence assembly yielded 29,358 scaffolds, encoding 82,546 viral proteins, with 15 new complete viral genomes from the 12 river and ocean locations. Viral diversity was clearly distinguished by river and ocean. Bacteriophages were the most abundant and occurred throughout the continuum. Viruses that infect eukaryotes were more abundant in the river, whereas phages appeared to have strong control over the host prokaryotic populations in the plume. PMID:28989970

Hydraulic Strategies and Response to El Niño Drought in Amazon Rainforest

NASA Astrophysics Data System (ADS)

Ivanov, V. Y.; Oliveira, R. S.; Brum, M., Jr.; Prohaska, N.; Albert, L.; Taylor, T.; Fatichi, S.; Agee, E.; Saleska, S. R.; Oliveira Junior, R. C.; Dye, D. G.; Wiedemann, K. T.

2016-12-01

Variability of tree-scale carbon and water uptake strategies is increasingly recognized to be of paramount importance for understanding the limits of drought resilience of tropical rainforests. Here, we present evidence of such variations using a set of ecohydrologic data collected through the DOE "GoAmazon" project, with a specific emphasis on the response of a seasonal rainforest in eastern Amazonia to the strong 2015 El Niño drought. Data from 50 sapflow sensors are combined with high-frequency observations on stem and leaf water potential as well as precision dendrometry. The emerging behavior shows a spectrum of successfully co-existing hydraulic strategies, ranging from tight control against xylem failure to a near lack of regulation of the water flux through the stomata, implying the existence of other mechanisms to deal with extreme tissue dehydration. These strategies also exhibit coupling with tree growth patterns and dynamics of non-structural carbohydrates, with the latter type of trees allocating more carbon to growth and less to internal reserves, while the opposite is true for the former tree type. The results suggest a new approach for integrating hydraulic traits and carbon-cycle dynamics, and a strategy for mapping traits to function in the next generation of predictive models of ecosystem dynamics.

Dissolved rainfall inputs and streamwater outputs in an undisturbed watershed on highly weathered soils in the Brazilian cerrado

NASA Astrophysics Data System (ADS)

Markewitz, Daniel; Resende, Julio C. F.; Parron, Lucilia; Bustamante, Mercedes; Klink, Carlos A.; Figueiredo, Ricardo De O.; Davidson, Eric A.

2006-08-01

The cerrados of Brazil cover 2 million km2. Despite the extent of these seasonally dry ecosystems, little watershed research has been focused in this region, particularly relative to the watersheds of the Amazon Basin. The cerrado shares pedogenic characteristics with the Amazon Basin in draining portions of the Brazilian shield and in possessing Oxisols over much of the landscape. The objective of this research was to quantify the stream water geochemical relationships of an undisturbed 1200 ha cerrado watershed for comparison to river geochemistry in the Amazon. Furthermore, this undisturbed watershed was used to evaluate stream discharge versus dissolved ion concentration relationships. This research was conducted in the Córrego Roncador watershed of the Reserva Ecológica do Roncador (RECOR) of the Instituto Brasileiro Geografia e Estatística (IBGE) near Brasilia, Brazil. Bulk precipitation and stream water chemistry were analysed between May 1998 and May 2000. The upland soils of this watershed are nutrient poor possessing total stocks of exchangeable elements in the upper 1 m of 81 +/- 13, 77 +/- 4, 25 +/- 3, and 1 +/- 1 kg ha-1 of K, Ca, Mg, and P, respectively. Bulk precipitation inputs of dissolved nutrients for this watershed are low and consistent with previous estimates. The nutrient-poor soils of this watershed, however, increase the relative importance of precipitation for nutrient replenishment to vegetation during episodes of ecosystem disturbance. Stream water dissolved loads were extremely dilute with conductivities ranging from 4 to 10 μS cm-1 during periods of high- and low-flow, respectively. Despite the low concentrations in this stream, geochemical relationships were similar to other Amazonian streams draining shield geologies. Discharge-concentration relationships for Ca and Mg in these highly weathered soils developed from igneous rocks of the Brazilian shield demonstrated a significant negative relationship indicating a continued predominance of groundwater baseflow contributions these cationic elements.

Lessons from forest FACE experiments provide guidance for Amazon-FACE science plan (Invited)

NASA Astrophysics Data System (ADS)

Norby, R. J.; Lapola, D. M.

2013-12-01

Free-air CO2 enrichment (FACE) experiments have provided novel insights into the ecological mechanisms controlling the cycling and storage of carbon in terrestrial ecosystems, and they provide a strong foundation for next-generation experiments in unexplored biomes. Specific lessons from FACE experiments include: (1) Carbon cycle responses are time-dependent because component processes have different rate constants: for example, net primary productivity is increased by elevated CO2, but the response may diminish with time as N cycling feedbacks become important. (2) Carbon partitioning patterns determine the fate of the extra C taken up by CO2-enriched plants, but partitioning responses remain an important challenge for ecosystem models. (3) The influence of N cycling on plant and ecosystem C cycling continues to be a critical uncertainty, and new experiments, especially in the tropics, must also consider P cycling. (4) Plant community structure can influence the ecosystem response to elevated CO2, but dynamic vegetation effects have not been adequately addressed. These experiences from FACE experiments in temperate forests are now guiding the development of a science plan for a FACE experiment in Amazonia. Models and small-scale experimental results agree that elevated CO2 will affect the metabolism of tropical ecosystems, but the qualitative and quantitative expression of the effects are largely unknown, representing a major source of uncertainty that limits our capacity to assess the vulnerability of the Amazon forest to climate change. Recognizing the high importance of the forests of the Amazon basin on global carbon, water, and energy cycles, biodiversity conservation, and the provision of essential services in Latin America, a consortium of Brazilian researchers and international collaborators have developed a science plan for Amazon-FACE. While the challenges presented both by infrastructure needs (roads, electricity, and provision of CO2) and biology (the size and diversity of the forest) are substantial, preliminary evaluation and past experience from temperate forest FACE experiments have supported the feasibility of an experiment comprising replicated 30-m diameter FACE plots in primary forest. The proposed site is the ZF2 research area 60 km north of Manaus and administered by Brazil's National Institute for Amazonia Research (INPA). The vegetation is representative of a dominant fraction of the forests occurring in the Amazon basin: old-growth closed-canopy terra firme (non-flooded) forest with trees 30-35 m in height on well drained clay soils. The major science questions guiding the experiment are closely informed by results of past FACE experiment and involve carbon metabolism, water use, nutrient cycling, interactions with environmental stressors, and the relationship between plant functional traits and community composition. FACE experiments can define ecological processes and mechanisms of responses for predictive models of ecosystem response, and models of CO2 response can define critical uncertainties and testable hypotheses for experiments; hence, the Amazon FACE experiment will feature a close integration of modeling and experimental approaches.

Severity of Scorpion Stings in the Western Brazilian Amazon: A Case-Control Study

PubMed Central

Queiroz, Amanda M.; Sampaio, Vanderson S.; Mendonça, Iran; Fé, Nelson F.; Sachett, Jacqueline; Ferreira, Luiz Carlos L.; Feitosa, Esaú; Wen, Fan Hui; Lacerda, Marcus; Monteiro, Wuelton

2015-01-01

Background Scorpion stings are a major public health problem in Brazil, with an increasing number of registered cases every year. Affecting mostly vulnerable populations, the phenomenon is not well described and is considered a neglected disease. In Brazil, the use of anti-venom formulations is provided free of charge. The associate scorpion sting case is subject to compulsory reporting. This paper describes the epidemiology and identifies factors associated with severity of scorpions stings in the state of Amazonas, in the Western Brazilian Amazon. Methodology/Principal Findings This study included all cases of scorpion stings in the state of Amazonas reported to the Brazilian Diseases Surveillance System from January 1, 2007 to December 31, 2014. A case-control study was conducted to identify factors associated with scorpions sting severity. A total of 2,120 cases were reported during this period. The mean incidence rate in the Amazonas was 7.6 per 100,000 inhabitants/year. Scorpion stings showed a large spatial distribution in the state and represent a potential occupational health problem for rural populations. There was a positive correlation between the absolute number of cases and the altimetric river levels in the Central (p<0.001; Rs = 0.479 linear) and Southwest (p = 0.032; linear Rs = 0.261) regions of the state. Cases were mostly classified as mild (68.6%), followed by moderate (26.8%), and severe (4.6%). The overall lethality rate was 0.3%. Lethality rate among children ≤10 years was 1.3%. Age <10 years [OR = 2.58 (95%CI = 1.47–4.55; p = 0.001)], stings occurring in the rural area [OR = 1.97 (95%CI = 1.18–3.29; p = 0.033) and in the South region of the state [OR = 1.85 (95%CI = 1.17–2.93; p = 0.008)] were independently associated with the risk of developing severity. Conclusions/Significance Scorpion stings show an extensive distribution in the Western Brazilian Amazon threatening especially rural populations, children ≤10 in particular. Thus, the mapping of scorpions fauna in different Amazon localities is essential and must be accompanied by the characterization of the main biological activities of the venoms. Urban and farming planning, in parallel with awareness of workers at risk for scorpion stings on the need for personal protective equipment use should be considered as public policies for preventing scorpionism. PMID:26061734

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

NASA Astrophysics Data System (ADS)

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

2015-12-01

We study a 3-D generalization of Budyko's framework that involves the complementary relationship between long-term mean actual evapotranspiration (E) and potential evapotranspiration (Ep), and that captures the mutual interdependence among E, Ep, and mean annual precipitation (P). For this purpose we use three dimensionless and dependent quantities: Ψ=E/P, Φ=Ep/P and Ω=E/Ep. We demonstrate analytically that Budyko-type equations are unable to capture the physical limit of the relation between Ω and Φ in humid environments, owing to the unfeasibility of Ep/P→0 at E/Ep=1. Using independent datasets from 146 sub-catchments in the Amazon River basin we overcome this physical inconsistency by proposing a physically consistent power law Ψ=kΦ e with pre-factor k=0.66 and scaling exponent e=0.83 (R2=0.93). The proposed power law is compared with other Budyko-type equations, namely those by Yang et al (2008) and Cheng et al (2011). Taking into account the goodness of fits with confidence bounds set at 95% level and the ability to comply with the physical limits of the 3-D space, our results show that the power law works better to model the long-term water and energy balances within the Amazon River basin. At the interannual time scale, parameters from the three studied equations are estimated for each catchment using 27 years of information and interesting regional patterns emerge, as well as evidence of space-time symmetry. In addition, results show that within individual catchments the parameters from the linear relationship by Cheng et al (2011) and from the power law resemble and are related to the partitioning of energy via evapotranspiration in terms of Ω. Finally, signs of co-evolution of catchments are explored by linking the emerging spatial patterns of the parameters with landscape properties that represent some of the main features of the Amazon River basin, including topography, water in soils and vegetation.

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

NASA Astrophysics Data System (ADS)

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

2015-10-01

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

Earth observation taken by the Expedition 20 crew

NASA Image and Video Library

2009-08-25

ISS020-E-034693 (25 Aug. 2009) --- Lake Erepecu and Rio Trombetas in Brazil are featured in this sun glint image photographed by an Expedition 20 crew member on the International Space Station. The 38 kilometers long Lake Erepecu runs parallel to the lower Rio (river) Trombetas which snakes along the lower half of this photograph. Waterbodies in the Amazon rainforest are often so dark they can be difficult to distinguish. In this image, however, the lake and river stand out from the uniform green of the forest in great detail as a result of sun glint on the water surface. Sun glint is light reflected off of a surface directly back towards the viewer, in this case a crew member onboard the space station. Soil color beneath the forest is red, as shown by airfield clearings near Porto Trombetas (upper left), a river port on the south side of the Trombetas River. The Trombetas flows into the Amazon River from the north about 800 kilometers from the Amazon mouth. Despite being so far from the sea, seagoing ore ships export most of Brazil?s bauxite from Porto Trombetas. Bauxite is the raw material formed in these tropical soils for the production of aluminum (the Trombetas bauxite mine is outside the upper margin of the image). Central Amazonia has many lakes like Erepecu?relatively straight, large waterbodies located just off the main axis of the large rivers. These lakes, as distinct from smaller floodplain lakes next to the large rivers, were created as rivers cut down during the repeated low global sea levels of the recent geological past (according to scientists, related to the ice ages of the last 1.7 million years). River water filled the valleys to form lakes during intervening periods of high sea level. Many larger rivers like the Trombetas and Amazon carried enough sediment to fill their immediate valleys?rivers flowing in unconsolidated sediment produce sinuous courses like those along the upper part of the image?but not enough to fill tributary valleys further from the axis of flow, so that lakes like Erepecu are formed.

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

NASA Technical Reports Server (NTRS)

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

2002-01-01

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

Variability of basin-scale terrestrial water storage from a novel application of the water budget equation: the Amazon and the Mississippi

NASA Astrophysics Data System (ADS)

Yoon, J.; Zeng, N.; Mariotti, A.; Swenson, S.

2007-12-01

In an approach termed the P-E-R (or simply PER) method, we apply the basin water budget equation to diagnose the long-term variability of the total terrestrial water storage (TWS). The key input variables are observed precipitation (P) and runoff (R), and estimated evaporation (E). Unlike typical offline land-surface model estimate where only atmospheric variables are used as input, the direct use of observed runoff in the PER method imposes an important constraint on the diagnosed TWS. Although there lack basin-scale observations of evaporation, the tendency of E to have significantly less variability than the difference between precipitation and runoff (P-R) minimizes the uncertainties originating from estimated evaporation. Compared to the more traditional method using atmospheric moisture convergence (MC) minus R (MCR method), the use of observed precipitation in PER method is expected to lead to general improvement, especially in regions atmospheric radiosonde data are too sparse to constrain the atmospheric model analyzed MC such as in the remote tropics. TWS was diagnosed using the PER method for the Amazon (1970-2006) and the Mississippi Basin (1928-2006), and compared with MCR method, land-surface model and reanalyses, and NASA's GRACE satellite gravity data. The seasonal cycle of diagnosed TWS over the Amazon is about 300 mm. The interannual TWS variability in these two basins are 100-200 mm, but multi-dacadal changes can be as large as 600-800 mm. Major droughts such as the Dust Bowl period had large impact with water storage depleted by 500 mm over a decade. Within the short period 2003-2006 when GRACE data was available, PER and GRACE show good agreement both for seasonal cycle and interannual variability, providing potential to cross-validate each other. In contrast, land-surface model results are significantly smaller than PER and GRACE, especially towards longer timescales. While we currently lack independent means to verify these long-term changes, simple error analysis using 3 precipitation datasets and 3 evaporation estimates suggest that the multi-decadal amplitude can be uncertain up to a factor of 2, while the agreement is high on interannual timescales. The large TWS variability implies the remarkable capacity of land-surface in storing and taking up water that may be under-represented in models. The results also suggest the existence of water storage memories on multi-year time scales, significantly longer than typically assumed seasonal timescales associated with surface soil moisture.

Amazon floodplain channels regulate channel-floodplain water exchange

NASA Astrophysics Data System (ADS)

Bates, P. D.; Baugh, C.; Trigg, M.

2017-12-01

We examine the role of floodplain channels in regulating the exchange of water between the Amazon main stem and its extensive floodplains using a combination of field survey, remote sensing and numerical modelling for a 30,000 km2 area around the confluence of the Solimões and Purus rivers. From Landsat imagery we identified 1762 individual floodplain channel reaches with total length of nearly 9300 line km that range in width from 900m to 20m. Using a boat survey we measured width and depth along 509 line km of floodplain channels in 45 separate reaches and used these data to develop geomorphic relationships between width and depth. This enabled reconstruction of the depth of all other channels in the Landsat survey to an RMSE of 2.5m. We then constructed a 2D hydraulic model of this site which included all 9300km of floodplain channels as sub-grid scale features using a recently developed version of the LISFLOOD-FP code. The DEM for the model was derived from a version of the SRTM Digital Elevation Model that was processed to remove vegetation artefacts. The model was run at 270m resolution over the entire 30,000 km2 domain for the period from 2002-2009. Simulations were run with and without floodplain channels to examine the impact of these features on floodplain flow dynamics and storage. Simulated floodplain channel hydraulics were validated against a combination of in-situ and remotely sensed data. Our results show that approximately 100 km3 of water is exchanged between the channel and the floodplain during a typical annual cycle, and 8.5±2.1% of mainstem flows is routed through the floodplain. The overall effect of floodplains channels was to increase the duration of connections between the Amazon River and the floodplain. Inclusion of floodplain channels in the model increased inundation volume by 7.3% - 11.3% at high water, and decreased it at low water by 4.0% - 16.6%, with the range in these estimates due to potential errors in floodplain channel geometry. Inundation extent in the model did not increase at high water, but low water flood extents declined by 8.8% - 29.7% due to increased connectivity between the floodplain and the mainstem. The wide range of flow decrease estimates demonstrates that the results are sensitive to errors in the estimation of floodplain channel geometries, particularly bed elevations.

Scaling properties reveal regulation of river flows in the Amazon through a forest reservoir

NASA Astrophysics Data System (ADS)

Salazar, Juan Fernando; Villegas, Juan Camilo; María Rendón, Angela; Rodríguez, Estiven; Hoyos, Isabel; Mercado-Bettín, Daniel; Poveda, Germán

2018-03-01

Many natural and social phenomena depend on river flow regimes that are being altered by global change. Understanding the mechanisms behind such alterations is crucial for predicting river flow regimes in a changing environment. Here we introduce a novel physical interpretation of the scaling properties of river flows and show that it leads to a parsimonious characterization of the flow regime of any river basin. This allows river basins to be classified as regulated or unregulated, and to identify a critical threshold between these states. We applied this framework to the Amazon river basin and found both states among its main tributaries. Then we introduce the forest reservoir hypothesis to describe the natural capacity of river basins to regulate river flows through land-atmosphere interactions (mainly precipitation recycling) that depend strongly on the presence of forests. A critical implication is that forest loss can force the Amazonian river basins from regulated to unregulated states. Our results provide theoretical and applied foundations for predicting hydrological impacts of global change, including the detection of early-warning signals for critical transitions in river basins.

Herpetofauna of the Northwest Amazon forest in the state of Maranhão, Brazil, with remarks on the Gurupi Biological Reserve.

PubMed

de Freitas, Marco Antonio; Vieira, Ruhan Saldanha; Entiauspe-Neto, Omar Machado; Sousa, Samantha Oliveira E; Farias, Tayse; Sousa, Alanna Grazieli; de Moura, Geraldo Jorge Barbosa

2017-01-01

Understanding the biodiversity of an area is the first step for establishing effective interventions for conservation, especially when it comes to herpetofauna, since 4.1% and 9.2%, respectively, of Brazilian amphibians and reptiles are endangered. The aim of this study is to identify the composition of the herpetofauna occurring in the Northwest Amazonian state of Maranhão, with a focus on the Gurupi Biological Reserve and surrounding areas. Samples were collected between May 2012 and October 2013 (18 months), through pitfall traps, time constrained active search, and opportunistic encounters, and these records were supplemented by specimens collected by third parties and by bibliographic records. A total of 131 species were recorded: 31 species of amphibians and 100 species of reptiles (six testudines, 30 lizards, two amphisbaenas, 60 snakes and two alligators), including some species new to the state of Maranhão and the northeast region of Brazil. This inventory contributes to the knowledge of the herpetofauna for the Belém Endemism Center, the most devastated region of the Brazilian Amazon, and considered poorly sampled.

Ecology, economy and management of an agroindustrial frontier landscape in the southeast Amazon

PubMed Central

Brando, Paulo M.; Coe, Michael T.; DeFries, Ruth; Azevedo, Andrea A.

2013-01-01

The papers in this special issue address a major challenge facing our society: feeding a population that is simultaneously growing and increasing its per capita food consumption, while preventing widespread ecological and social impoverishment in the tropics. By focusing mostly on the Amazon's most dynamic agricultural frontier, Mato Grosso, they collectively clarify some key elements of achieving more sustainable agriculture. First, stakeholders in commodity-driven agricultural Amazonian frontiers respond rapidly to multiple forces, including global markets, international pressures for sustainably produced commodities and national-, state- and municipality-level policies. These forces can encourage or discourage deforestation rate changes within a short time-period. Second, agricultural frontiers are linked systems, land-use change is linked with regional climate, forest fires, water quality and stream discharge, which in turn are linked with the well-being of human populations. Thus, land-use practices at the farm level have ecological and social repercussions far removed from it. Third, policies need to consider the full socio-economic system to identify the efficacy and consequences of possible land management strategies. Monitoring to devise suitable management approaches depends not only on tracking land-use change, but also on monitoring the regional ecological and social consequences. Mato Grosso's achievements in reducing deforestation are impressive, yet they are also fragile. The ecological and social consequences and the successes and failures of management in this region can serve as an example of possible trajectories for other commodity-driven tropical agricultural frontiers. PMID:23610163

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.

Pharmacokinetics of voriconazole after oral administration of single and multiple doses in Hispaniolan Amazon parrots (Amazona ventralis).

PubMed

Sanchez-Migallon Guzman, David; Flammer, Keven; Papich, Mark G; Grooters, Amy M; Shaw, Shannon; Applegate, Jeff; Tully, Thomas N

2010-04-01

To determine the pharmacokinetics and safety of voriconazole administered orally in single and multiple doses in Hispaniolan Amazon parrots (Amazona ventralis). 15 clinically normal adult Hispaniolan Amazon parrots. Single doses of voriconazole (12 or 24 mg/kg) were administered orally to 15 and 12 birds, respectively; plasma voriconazole concentrations were determined at intervals via high-pressure liquid chromatography. In a multiple-dose trial, voriconazole (18 mg/kg) or water was administered orally to 6 and 4 birds, respectively, every 8 hours for 11 days (beginning day 0); trough plasma voriconazole concentrations were evaluated on 3 days. Birds were monitored daily, and clinicopathologic variables were evaluated before and after the trial. Voriconazole elimination half-life was short (0.70 to 1.25 hours). In the single-dose experiments, higher drug doses yielded proportional increases in the maximum plasma voriconazole concentration (C(max)) and area under the curve (AUC). In the multiple-dose trial, C(max), AUC, and plasma concentrations at 2 and 4 hours were decreased on day 10, compared with day 0 values; however, there was relatively little change in terminal half-life. With the exception of 1 voriconazole-treated parrot that developed polyuria, adverse effects were not evident. In Hispaniolan Amazon parrots, oral administration of voriconazole was associated with proportional kinetics following administration of single doses and a decrease in plasma concentration following administration of multiple doses. Oral administration of 18 mg of voriconazole/kg every 8 hours would require adjustment to maintain therapeutic concentrations during long-term treatment. Safety and efficacy of voriconazole treatment in this species require further investigation.

A long-term perspective on deforestation rates in the Brazilian Amazon

NASA Astrophysics Data System (ADS)

Velasco Gomez, M. D.; Beuchle, R.; Shimabukuro, Y.; Grecchi, R.; Simonetti, D.; Eva, H. D.; Achard, F.

2015-04-01

Monitoring tropical forest cover is central to biodiversity preservation, terrestrial carbon stocks, essential ecosystem and climate functions, and ultimately, sustainable economic development. The Amazon forest is the Earth's largest rainforest, and despite intensive studies on current deforestation rates, relatively little is known as to how these compare to historic (pre 1985) deforestation rates. We quantified land cover change between 1975 and 2014 in the so-called Arc of Deforestation of the Brazilian Amazon, covering the southern stretch of the Amazon forest and part of the Cerrado biome. We applied a consistent method that made use of data from Landsat sensors: Multispectral Scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+) and Operational Land Imager (OLI). We acquired suitable images from the US Geological Survey (USGS) for five epochs: 1975, 1990, 2000, 2010, and 2014. We then performed land cover analysis for each epoch using a systematic sample of 156 sites, each one covering 10 km x 10 km, located at the confluence point of integer degree latitudes and longitudes. An object-based classification of the images was performed with five land cover classes: tree cover, tree cover mosaic, other wooded land, other land cover, and water. The automatic classification results were corrected by visual interpretation, and, when available, by comparison with higher resolution imagery. Our results show a decrease of forest cover of 24.2% in the last 40 years in the Brazilian Arc of Deforestation, with an average yearly net forest cover change rate of -0.71% for the 39 years considered.

Global Climate Change (GCC) Issues and Their Impacts on the US Army Corps of Engineers

DTIC Science & Technology

1991-11-01

Amazon River flow. At first this flow was channeled down the Mississippi River to the Gulf of Mexico: "... about 11,000 years ago, however, a major...Foraminifera ( fossil evidence of microorganisms that inhabit water masses of specific temperature and salinity) from surface waters of the Gulf of...records can be tied into tree ring records (both current and fossilized ) to produce an accurate record for the last 8,200 years. This type of study is

Sustained Presence of Cutaneous Leishmaniasis in Urban Manaus, the Largest Human Settlement in the Amazon.

PubMed

Benício, Ednelza; Cordeiro, Mayara; Monteiro, Hannah; Saboia Moura, Marco Antônio; Oliveira, Cintia; Nunes Gadelha, Ellen Pricilla; Chrusciak-Talhari, Anette; Talhari, Carolina; de Lima Ferreira, Luiz Carlos; Mira, Marcelo Távora; Lima Machado, Paulo Roberto; Talhari, Sinésio; Schriefer, Albert

2015-12-01

The Amazon is responsible for approximately 40% of the American tegumentary leishmaniasis (ATL) in Brazil. Herein the sustained presence of ATL in Manaus, the largest settlement in the Amazon, was investigated. Records of notification of historic cases, and data from cases prospectively enrolled in the Tropical Medicine Foundation of the Amazonas State were used. Geographic coordinates of prospective patients' living sites were used to detect inner-city clusters of ATL. Infecting Leishmania species was determined by polymerase chain reaction. Among prospectively enrolled subjects, 94.8% were infected with Leishmania (Viannia) guyanensis, 76.7% were male, 30.2% were 0-20 years old, and 69.8% had an urban residence. Historic cases showed a profile similar to that of prospectively enrolled subjects. Several clusters of ATL, widely distributed within the city of Manaus, could be detected. In conclusion, there was a high frequency of disease in young age groups and cases clustered in urban neighborhoods. It cannot be determined from these data whether transmission of these cases occurred within or outside the city of Manaus. © The American Society of Tropical Medicine and Hygiene.

Sustained Presence of Cutaneous Leishmaniasis in Urban Manaus, the Largest Human Settlement in the Amazon

PubMed Central

Benício, Ednelza; Cordeiro, Mayara; Monteiro, Hannah; Moura, Marco Antônio Saboia; Oliveira, Cintia; Gadelha, Ellen Pricilla Nunes; Chrusciak-Talhari, Anette; Talhari, Carolina; de Lima Ferreira, Luiz Carlos; Mira, Marcelo Távora; Machado, Paulo Roberto Lima; Talhari, Sinésio; Schriefer, Albert

2015-01-01

The Amazon is responsible for approximately 40% of the American tegumentary leishmaniasis (ATL) in Brazil. Herein the sustained presence of ATL in Manaus, the largest settlement in the Amazon, was investigated. Records of notification of historic cases, and data from cases prospectively enrolled in the Tropical Medicine Foundation of the Amazonas State were used. Geographic coordinates of prospective patients' living sites were used to detect inner-city clusters of ATL. Infecting Leishmania species was determined by polymerase chain reaction. Among prospectively enrolled subjects, 94.8% were infected with Leishmania (Viannia) guyanensis, 76.7% were male, 30.2% were 0–20 years old, and 69.8% had an urban residence. Historic cases showed a profile similar to that of prospectively enrolled subjects. Several clusters of ATL, widely distributed within the city of Manaus, could be detected. In conclusion, there was a high frequency of disease in young age groups and cases clustered in urban neighborhoods. It cannot be determined from these data whether transmission of these cases occurred within or outside the city of Manaus. PMID:26483119

Estimating forest biomass and identifying low-intensity logging areas using airborne scanning lidar in Antimary State Forest, Acre State, Western Brazilian Amazon

Treesearch

Marcus V.N. d' Oliveira; Stephen E. Reutebuch; Robert J. McGaughey; Hans-Erik. Andersen

2012-01-01

The objectives of this study were to estimate above ground forest biomass and identify areas disturbed by selective logging in a 1000 ha Brazilian tropical forest in the Antimary State Forest using airborne lidar data. The study area consisted of three management units, two of which were unlogged, while the third unit was selectively logged at a low intensity. A...

Occupation and urbanization of Roraima State, Brazil.

PubMed

Diniz, A

1997-01-01

The author examines settlement patterns and urbanization of the remote area of Roraima State, Brazil. "A survey conducted in the capital city, Boa Vista, provides information on migration histories and migrants' characteristics.... Current views of urbanization of the Amazon [region] are focused on the displacement factor that development and state geopolitics have upon rural settlements...." The author also suggests that more attention needs to be paid to the characteristics of migrants in the urban areas. (EXCERPT)

Brazil-U.S. Relations

DTIC Science & Technology

2009-06-03

the Amazon falls within Brazilian borders, making Brazil home to 40% of the world’s remaining tropical forests.96 The Brazilian Amazon was largely...20 Amazon Conservation......................................................................................................... 20 Domestic Efforts...independence in 1822, Brazil occupies almost half of the continent of South America and boasts immense biodiversity, including the vast Amazon

The estuarine chemistry and isotope systematics of 234,238U in the Amazon and Fly Rivers

USGS Publications Warehouse

Swarzenski, P.; Campbell, P.; Porcelli, D.; McKee, B.

2004-01-01

Natural concentrations of 238U and ??234U values were determined in estuarine surface waters and pore waters of the Amazon and Fly (Papua New Guinea) Rivers to investigate U transport phenomena across river-dominated land-sea margins. Discharge from large, tropical rivers is a major source of dissolved and solid materials transported to the oceans, and are important in defining not only oceanic mass budgets, but also terrestrial weathering rates. On the Amazon shelf, salinity-property plots of dissolved organic carbon, pH and total suspended matter revealed two vastly contrasting water masses that were energetically mixed. In this mixing zone, the distribution of uranium was highly non-conservative and exhibited extensive removal from the water column. Uranium removal was most pronounced within a salinity range of 0-16.6, and likely the result of scavenging and flocculation reactions with inorganic (i.e., Fe/Mn oxides) and organic colloids/particles. Removal of uranium may also be closely coupled to exchange and resuspension processes at the sediment/water interface. An inner-shelf pore water profile indicated the following diagenetic processes: extensive (???1 m) zones of Fe(III) - and, to a lesser degree, Mn(IV) - reduction in the absence of significant S(II) concentrations appeared to facilitate the formation of various authigenic minerals (e.g., siderite, rhodocrosite and uraninite). The pore water dissolved 238U profile co-varied closely with Mn(II). Isotopic variations as evidenced in ??234U pore waters values from this site revealed information on the origin and history of particulate uranium. Only after a depth of about 1 m did the ??234U value approach unity (secular equilibrium), denoting a residual lattice bound uranium complex that is likely an upper-drainage basin weathering product. This suggests that the enriched ??234U values represent a riverine surface complexation product that is actively involved in Mn-Fe diagenetic cycles and surface complexation reactions. In the Fly River estuary, 238U appears to exhibit a reasonably conservative distribution as a function of salinity. The absence of observed U removal does not necessarily imply non-reactivity, but instead may record an integration of concurrent U removal and release processes. There is not a linear correlation between ??234U vs. 1/ 238U that would imply simple two component mixing. It is likely that resuspension of bottom sediments, prolonged residence times in the lower reaches of the Fly River, and energetic particle-colloid interactions contribute to the observed estuarine U distribution. The supply of uranium discharged from humid, tropical river systems to the sea appears to be foremost influenced by particle/water interactions that are ultimately governed by the particular physiographic and hydrologic characteristics of an estuary. ?? 2004 Elsevier Ltd. All rights reserved.

Amazonian and neotropical plant communities on glacial time-scales: The failure of the aridity and refuge hypotheses

NASA Astrophysics Data System (ADS)

Colinvaux, P. A.; De Oliveira, P. E.; Bush, M. B.

2000-01-01

Plants respond to Pleistocene climatic change as species, not as associations or biomes. This has been demonstrated unequivocally by paleobotanical data for temperate latitudes. In the far richer vegetations of the tropics species populations also fluctuated independently in response to climatic forcing, from their longlasting glacial states to the patterns of brief interglacials like the present and back again. We use pollen data to reconstruct the vegetation of the Amazon basin in oxygen isotope stages 3 and 2 of the last glaciation in order to measure how the plant populations of the Amazon responded to the global warming at the onset of the Holocene. We find that plant communities of the neotropics vent copious pollen to lake sediments and that this pollen yields powerful signals for community composition. Three continuous sedimentary records reaching through oxygen isotope stage 2 are available from the Amazon lowlands, those from Carajas, Lake Pata and marine deposits off the mouth of the Amazon River. All three records yield pollen histories of remarkable constancy and stability. By comparing them with deposits of equal antiquity from the cerrado (savanna) of central Brazil, we show that most of the Amazon lowlands remained under forest throughout a glacial cycle. This forest was never fragmented by open vegetation as postulated by the refugia hypothesis. Instead the intact forest of glacial times included significant populations of plants that are now montane, suggesting that the global warming of the early Holocene resulted in the expulsion of heat intolerant plants from the lowland forest. Pollen data from the Amazonian flank of the Andes and from Pacific Panama provide evidence that populations of these heat intolerant plants survive the heat of interglacials in part by maintaining large populations at cooler montane altitudes. Our conclusion that the Amazon lowlands were forested in glacial times specifically refutes the hypothesis of Amazonian glacial aridity. Accordingly we examine the geomorphological evidence for glacial aridity and find it wanting. Of the three paleodune systems reported for tropical South America, that of NE Brazil was active in the Holocene as well as the Pleistocene. Parts of NE Brazil were actually moister than now in late-glacial times. Paleodunes in the Pantanal have never been seen on the ground, and those in the Orinoco Llanos are undated and may be of any age since the Tertiary. Arkosic sands in the Amazon fan deposits came from the Andean foothills or from down cutting by rivers and cannot be evidence of a former arid land surface. White sands of Amazonia formed as podzols, not by aeolian activity. Such Amazonian stone lines as have received critical scrutiny are concretionary pisolites in stratigraphic formations that are more than ten million years old. Although the Amazon was never arid, modeling cooler glacial tropics gives plausibility to a somewhat drier Amazon in glacial times, a concept given substance by pollen data for the movement of ecotones in Rondonia, by stream histories in the Bolivian Andes, and by evidence for lowered lake levels at Carajas and Lake Pata. But this reduced precipitation was never enough to fragment the forest in the Amazon lowlands themselves. Pleistocene mammals of the Napo river valley in Ecuador were able to live along the river system in a forested landscape. Our data suggest that the Amazon forests have been stable since the start of the Pleistocene, a fact that has contributed to the storage of vast diversity. The coming anthropogenic global warming and CO 2 enrichment will add to the global warming already endured by Amazon biota in the Holocene. We think it possible that the expulsion from the lowland forests of heat intolerant species is already complete and that the forest property of maintaining its own microhabitat will allow the high species richness to survive more global warming, provided large enough tracts of forest are preserved.

Molecular epidemiology of hepatitis B and hepatitis delta viruses circulating in the Western Amazon region, North Brazil

PubMed Central

2014-01-01

Background Hepatitis B virus (HBV) and hepatitis D virus (HDV) represent important public health problems in the Western Amazon region with reported cases of fulminant hepatitis. This cross sectional study describes HBV and HDV genotypes circulating in the Brazilian Amazon region. Methods HBsAg positive individuals (n = 224) were recruited in Manaus/Amazonas State (130 blood donors from the Hematology and Hemotherapy Foundation from Amazonas/HEMOAM; 60 subjects from outpatient clinic) and in Eirunepe city (n = 34) from 2003–2009. Most participants (n = 153) lived in Manaus, 63 were from 20 remote isolated municipalities, 8 lived outside Amazonas State. Genotyping was based on PCR products: HBV genotype A-F specific primers, restricted length polymorphism for HDV. HDV isolates were directly sequenced (delta antigen 405 nucleotide fragment) and phylogenetic analysis performed (MEGA; neighbor-joining, Kimura’s two parameter). Results Most participants were young adult males and HBV mono-infection predominated (70.5%, 158/224). Among blood donors, outpatient subjects and individuals from Eirunepe, HBV/A prevailed followed by HBV/D and F (p > 0.05). HBV/A was more frequent in blood donors (p < 0.05). HBV-HDV coinfection rate was 8.5% in blood donors (11/130), 65.0% (39/60) in outpatient subjects and 47.0% (16/34) in individuals from Eirunepe. Compared to blood donors, coinfection was higher in outpatient subjects (65.0% versus 8.5%; RR = 5.0; CI 3.4-7.9; p < 0.0001) and in subjects from Eirunepe (47.0% versus 8.5%; RR = 5.5; CI 3.0-9.9; p < 0.0001). HBV-HDV coinfection rates were higher in patients from highly endemic remote cities. Only HDV genotype 3 was detected, HBV/F-HDV/3 predominated (20/38; 52.7%), followed by HBV/A-HDV/3 (31.6%; 12/38) and HBV/D-HDV/3 (15.8%; 6/38). Conclusions The description of HBV and HDV genotypes circulating in the western Amazon can contribute to a better understanding of their relevance on the regional epidemics. These infections are highly endemic in the Amazon where their control is challenged by its vast territorial dimension with small, hard-to-reach municipalities dispersed into the jungle and populated by diverse ethnic groups. PMID:24555665

Drivers of house invasion by sylvatic Chagas disease vectors in the Amazon-Cerrado transition: A multi-year, state-wide assessment of municipality-aggregated surveillance data.

PubMed

Brito, Raíssa N; Gorla, David E; Diotaiuti, Liléia; Gomes, Anália C F; Souza, Rita C M; Abad-Franch, Fernando

2017-11-01

Insecticide spraying efficiently controls house infestation by triatomine bugs, the vectors of Trypanosoma cruzi. The strategy, however, is ineffective against sylvatic triatomines, which can transmit Chagas disease by invading (without colonizing) man-made structures. Despite growing awareness of the relevance of these transmission dynamics, the drivers of house invasion by sylvatic triatomines remain poorly understood. About 12,000 sylvatic triatomines were caught during routine surveillance in houses of Tocantins state, Brazil, in 2005-2013. Using negative binomial regression, information-theoretic model evaluation/averaging, and external model validation, we investigated the effects of regional (Amazon/Cerrado), landscape (preservation/disturbance), and climate covariates (temperature, rainfall) on the municipality-aggregated numbers of house-invading Rhodnius pictipes, R. robustus, R. neglectus, and Panstrongylus geniculatus. House invasion by R. pictipes and R. robustus was overall more frequent in the Amazon biome, tended to increase in municipalities with more well-preserved land, and decreased in rainier municipalities. Across species, invasion decreased with higher landscape-disturbance levels and in hotter-day municipalities. Invasion by R. neglectus and P. geniculatus increased somewhat with more land at intermediate disturbance and peaked in average-rainfall municipalities. Temperature effects were more pronounced on P. geniculatus than on Rhodnius spp. We report widespread, frequent house invasion by sylvatic triatomines in the Amazon-Cerrado transition. Our analyses indicate that readily available environmental metrics may help predict the risk of contact between sylvatic triatomines and humans at coarse geographic scales, and hint at specific hypotheses about climate and deforestation effects on those vectors-with some taxon-specific responses and some seemingly general trends. Thus, our focal species appear to be quite sensitive to higher temperatures, and might be less common in more heavily-disturbed than in better-preserved environments. This study illustrates, in sum, how entomological routine-surveillance data can be efficiently used for Chagas disease risk prediction and stratification when house-colonizing vectors are absent.

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

NASA Astrophysics Data System (ADS)

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

2013-12-01

Scientific understanding of neotropical floodplains comes mainly from work on large rivers with predictable seasonal flooding regimes. Less studied rivers and floodplains on the Andean-Amazon interface are distinct in their hydrology, with more erratic flow regimes, and thus ecological roles of floodplain inundation differ in those ecosystems. Multiple and unpredictable flooding events control inundation of floodplains, with important implications for fish and wildlife, plant communities, and human activities. Wetlands along the river corridor exist across a continuum from strong river control to influence only by local waters, with the latter often lying on floodplain paleoterraces. The goal of this study was to understand the hydrological interactions and habitat diversity of the Napo River, a major Amazon tributary that originates in the Andes and drains exceptionally biodiverse Andean foreland plains. This river system is envisioned by developers as an industrial waterway that would require hydrological alterations and affect floodplain ecosystems. Water level regimes of the Napo River and its associated environments were assessed using networks of data loggers that recorded time under water across transects extending inland from the river across more than 100 sites and for up to 5 years. These networks also included rising stage samplers that collected flood water samples for determination of their origin (i.e., Andean rivers vs. local waters) based on hydrochemical composition. In addition, this work entails a classification of aquatic environments of the Napo Basin using an object-oriented remote sensing approach to simultaneously analyze optical and radar satellite imagery and digital elevation models to better assess the extent and diversity of flooded environments. We found out a continuum of hydrological regimes and aquatic habitats along the Napo River floodplains that are linked to the river hydrology in different degrees. Overall, environments that are proximal or that have high hydrological connectivity are riverine controlled versus systems that are distal or that have less or no connectivity that rely on rainwater or local runoff as a source of flooding. Outcomes of this research gave us insight on the extent and diversity of aquatic habitats of the Napo River, the role that the river has on their ecohydrology, the potential effects of different hydrologic scenarios on these ecosystems, and the management measures that need to be considered to support conservation in the region.

Business as Usual: Amazon.com and the Academic Library

ERIC Educational Resources Information Center

Van Ullen, Mary K.; Germain, Carol Anne

2002-01-01

In 1999, Steve Coffman proposed that libraries form a single interlibrary loan based entity patterned after Amazon.com. This study examined the suitability of Amazon.com's Web interface and record enhancements for academic libraries. Amazon.com could not deliver circulating monographs in the University at Albany Libraries' collection quickly…

Rickettsia amblyommatis infecting ticks and exposure of domestic dogs to Rickettsia spp. in an Amazon-Cerrado transition region of northeastern Brazil.

PubMed

Costa, Francisco B; da Costa, Andréa P; Moraes-Filho, Jonas; Martins, Thiago F; Soares, Herbert S; Ramirez, Diego G; Dias, Ricardo A; Labruna, Marcelo B

2017-01-01

This study was performed in Maranhão state, a transition area two Brazilian biomes, Amazon and Cerrado. During 2011-2013, 1,560 domestic dogs were sampled for collection of serum blood samples and ticks in eight counties (3 within the Amazon and 5 within the Cerrado). A total of 959 ticks were collected on 150 dogs (9.6%). Rhipicephalus sanguineus sensu lato (s.l.) was the most abundant tick (68% of all collected specimens), followed by Amblyomma cajennense sensu lato (s.l.) (12.9%), Amblyomma parvum (9.2%), and Amblyomma ovale (5.2%). Other less abundant species (<1%) were Amblyomma oblongoguttatum, Rhipicephalus microplus, Haemaphysalis juxtakochi, and Amblyomma rotundatum. Females of A. cajennense s.l. ticks were morphologically identified as A. cajennense sensu stricto (s.s.) or A. sculptum. Molecular analyses of 779 canine ticks revealed three Rickettsia species: Rickettsia amblyommatis in 1% (1/100) A. cajennense s.l., 'Candidatus Rickettsia andeanae' in 20.7% (12/58) A. parvum, Rickettsia bellii in 6.8% (3/44) A. ovale and 100% (1/1) A. rotundatum ticks. An additional collection of A. sculptum from horses in a Cerrado area, and A. cajennense s.s. from pigs in an Amazon area revealed R. amblyommatis infecting only the A. cajennense s.s. ticks. Serological analysis of the 1,560 canine blood samples revealed 12.6% canine seroreactivity to Rickettsia spp., with the highest specific seroreactivity rate (10.2%) for R. amblyommatis. Endpoint titers to R. amblyommatis were significantly higher than those for the other Rickettsia antigens, suggesting that most of the seroreactive dogs were exposed to R. amblyommatis-infected ticks. Highest canine seroreactivity rates per locality (13.1-30.8%) were found in Amazon biome, where A. cajennense s.s. predominated. Lowest seroreactivity rates (1.9-6.5%) were found in Cerrado localities that were further from the Amazon, where A. sculptum predominated. Multivariate analyses revealed that canine seroreactivity to Rickettsia spp. or R. amblyommatis was statistically associated with rural dogs, exposed to Amblyomma ticks.

Rickettsia amblyommatis infecting ticks and exposure of domestic dogs to Rickettsia spp. in an Amazon-Cerrado transition region of northeastern Brazil

PubMed Central

Costa, Francisco B.; da Costa, Andréa P.; Moraes-Filho, Jonas; Martins, Thiago F.; Soares, Herbert S.; Ramirez, Diego G.; Dias, Ricardo A.

2017-01-01

This study was performed in Maranhão state, a transition area two Brazilian biomes, Amazon and Cerrado. During 2011–2013, 1,560 domestic dogs were sampled for collection of serum blood samples and ticks in eight counties (3 within the Amazon and 5 within the Cerrado). A total of 959 ticks were collected on 150 dogs (9.6%). Rhipicephalus sanguineus sensu lato (s.l.) was the most abundant tick (68% of all collected specimens), followed by Amblyomma cajennense sensu lato (s.l.) (12.9%), Amblyomma parvum (9.2%), and Amblyomma ovale (5.2%). Other less abundant species (<1%) were Amblyomma oblongoguttatum, Rhipicephalus microplus, Haemaphysalis juxtakochi, and Amblyomma rotundatum. Females of A. cajennense s.l. ticks were morphologically identified as A. cajennense sensu stricto (s.s.) or A. sculptum. Molecular analyses of 779 canine ticks revealed three Rickettsia species: Rickettsia amblyommatis in 1% (1/100) A. cajennense s.l., ‘Candidatus Rickettsia andeanae’ in 20.7% (12/58) A. parvum, Rickettsia bellii in 6.8% (3/44) A. ovale and 100% (1/1) A. rotundatum ticks. An additional collection of A. sculptum from horses in a Cerrado area, and A. cajennense s.s. from pigs in an Amazon area revealed R. amblyommatis infecting only the A. cajennense s.s. ticks. Serological analysis of the 1,560 canine blood samples revealed 12.6% canine seroreactivity to Rickettsia spp., with the highest specific seroreactivity rate (10.2%) for R. amblyommatis. Endpoint titers to R. amblyommatis were significantly higher than those for the other Rickettsia antigens, suggesting that most of the seroreactive dogs were exposed to R. amblyommatis-infected ticks. Highest canine seroreactivity rates per locality (13.1–30.8%) were found in Amazon biome, where A. cajennense s.s. predominated. Lowest seroreactivity rates (1.9–6.5%) were found in Cerrado localities that were further from the Amazon, where A. sculptum predominated. Multivariate analyses revealed that canine seroreactivity to Rickettsia spp. or R. amblyommatis was statistically associated with rural dogs, exposed to Amblyomma ticks. PMID:28594882

Sources and sinks for nitrous oxide and experimental studies of the source of atmospheric COS, CS-2 and CH-3-Cl

NASA Technical Reports Server (NTRS)

Wofsy, S. C.

1984-01-01

Studies of the air and water chemistry in the Amazon region of Brazil were undertaken. Harvard scientists were invited to participate in several experiments at INPA facilities, at other sites in Brazil, and aboard the RV Calypso of the Cousteau Society. Expeditions and participants are summarized.

Patterns of diversification in the discus fishes (Symphysodon spp. Cichlidae) of the Amazon basin.

PubMed

Farias, Izeni Pires; Hrbek, Tomas

2008-10-01

We carried out a phylogeograhic and population genetic analysis of fishes of the taxonomically contentious genus Symphysodon from the Amazon basin in order to test hypotheses of relationships among taxonomic units, and potential processes driving diversification within this genus. We sampled 334 individuals of the genus Symphysodon from 24 localities that span the complete geographic distribution of this genus. The sampling scheme included all known phenotypic groups, species and subspecies. Analyses were based on 474 bp of the mitochondrial control region and 1443 bp of the exon 3 of RAG1 gene. We observed 102 mtDNA haplotypes defined by 89 segregating sites, and 5 nuDNA alleles defined by three segregating sites. Maximum-likelihood, Bayesian-inference and statistical parsimony analyses revealed three well defined monophyletic groups. These clades corresponded to the 'green' and 'blue' groups of Symphysodon aequifasciatus, and to a previously morphologically unrecognized clade from the Xingu River drainage. These three clades were nested within a paraphyletic assemblage consisting of the 'brown' group of S. aequifasciatus and of both described subspecies of S. discus, the 'Heckel' and the 'abacaxi' discus. Nuclear allele sharing was observed among groups, but there were significant differences in frequencies. We inferred several processes including past fragmentation among groups, and restricted gene flow with isolation by distance within the paraphyletic 'brown+Heckel+abacaxi' groups, and suggest that differences among the 'blue', 'Heckel' and 'brown' groups are potentially maintained by differences in water chemistry preferences. We further inferred colonization of the western Amazon basin by an ancestor of the 'green' clade. The 'green' group was the only group with a pattern of haplotype distribution consistent of a demographic expansion, and the divergence of this clade from other groups of discus was consistent with recent geologic evidence on the breach of the Purus Arch which separates western Amazon from eastern Amazon. We further hypothesized that the differentiation of the 'Xingu' clade could be due to vicariance events resulting from Pleistocene sea level, and thus Amazon River level fluctuations. We discuss the bearings of our results on the current taxonomy of this group, and on the biological reality of the different forms, subspecies and species of Symphysodon concluding that we are probably observing a process of diversification, and therefore taxonomy will remain contentious.

A Synoptic Assessment of the Amazon River-Ocean Continuum during Boreal Autumn: From Physics to Plankton Communities and Carbon Flux.

PubMed

Araujo, Moacyr; Noriega, Carlos; Hounsou-Gbo, Gbekpo Aubains; Veleda, Doris; Araujo, Julia; Bruto, Leonardo; Feitosa, Fernando; Flores-Montes, Manuel; Lefèvre, Nathalie; Melo, Pedro; Otsuka, Amanda; Travassos, Keyla; Schwamborn, Ralf; Neumann-Leitão, Sigrid

2017-01-01

The Amazon generates the world's largest offshore river plume, which covers extensive areas of the tropical Atlantic. The data and samples in this study were obtained during the oceanographic cruise Camadas Finas III in October 2012 along the Amazon River-Ocean Continuum (AROC). The cruise occurred during boreal autumn, when the river plume reaches its maximum eastward extent. In this study, we examine the links between physics, biogeochemistry and plankton community structure along the AROC. Hydrographic results showed very different conditions, ranging from shallow well-mixed coastal waters to offshore areas, where low salinity Amazonian waters mix with open ocean waters. Nutrients, mainly [Formula: see text] and [Formula: see text], were highly depleted in coastal regions, and the magnitude of primary production was greater than that of respiration (negative apparent oxygen utilization). In terms of phytoplankton groups, diatoms dominated the region from the river mouth to the edge of the area affected by the North Brazil Current (NBC) retroflection (with chlorophyll a concentrations ranging from 0.02 to 0.94 mg m -3 ). The North Equatorial Counter Current (NECC) region, east of retroflection, is fully oligotrophic and the most representative groups are Cyanobacteria and dinoflagellates. Additionally, in this region, blooms of cyanophyte species were associated with diatoms and Mesozooplankton (copepods). A total of 178 zooplankton taxa were observed in this area, with Copepoda being the most diverse and abundant group. Two different zooplankton communities were identified: a low-diversity, high-abundance coastal community and a high-diversity, low-abundance oceanic community offshore. The CO 2 fugacity (fCO 2 sw), calculated from total alkalinity (1,450 < TA < 2,394 μmol kg -1 ) and dissolved inorganic carbon (1,303 < DIC < 2,062 μmol kg -1 ) measurements, confirms that the Amazon River plume is a sink of atmospheric CO 2 in areas with salinities <35 psu, whereas, in regions with salinities >35 and higher-intensity winds, the CO 2 flux is reversed. Lower fCO 2 sw values were observed in the NECC area. The ΔfCO 2 in this region was less than 5 μatm (-0.3 mmol m -2 d -1 ), while the ΔfCO 2 in the coastal region was approximately 50 μatm (+3.7 mmol m -2 d -1 ). During the cruise, heterotrophic and autotrophic processes were observed and are indicative of the influences of terrestrial material and biological activity, respectively.

A Synoptic Assessment of the Amazon River-Ocean Continuum during Boreal Autumn: From Physics to Plankton Communities and Carbon Flux

PubMed Central

Araujo, Moacyr; Noriega, Carlos; Hounsou-gbo, Gbekpo Aubains; Veleda, Doris; Araujo, Julia; Bruto, Leonardo; Feitosa, Fernando; Flores-Montes, Manuel; Lefèvre, Nathalie; Melo, Pedro; Otsuka, Amanda; Travassos, Keyla; Schwamborn, Ralf; Neumann-Leitão, Sigrid

2017-01-01

The Amazon generates the world's largest offshore river plume, which covers extensive areas of the tropical Atlantic. The data and samples in this study were obtained during the oceanographic cruise Camadas Finas III in October 2012 along the Amazon River-Ocean Continuum (AROC). The cruise occurred during boreal autumn, when the river plume reaches its maximum eastward extent. In this study, we examine the links between physics, biogeochemistry and plankton community structure along the AROC. Hydrographic results showed very different conditions, ranging from shallow well-mixed coastal waters to offshore areas, where low salinity Amazonian waters mix with open ocean waters. Nutrients, mainly NO3− and SiO2−, were highly depleted in coastal regions, and the magnitude of primary production was greater than that of respiration (negative apparent oxygen utilization). In terms of phytoplankton groups, diatoms dominated the region from the river mouth to the edge of the area affected by the North Brazil Current (NBC) retroflection (with chlorophyll a concentrations ranging from 0.02 to 0.94 mg m−3). The North Equatorial Counter Current (NECC) region, east of retroflection, is fully oligotrophic and the most representative groups are Cyanobacteria and dinoflagellates. Additionally, in this region, blooms of cyanophyte species were associated with diatoms and Mesozooplankton (copepods). A total of 178 zooplankton taxa were observed in this area, with Copepoda being the most diverse and abundant group. Two different zooplankton communities were identified: a low-diversity, high-abundance coastal community and a high-diversity, low-abundance oceanic community offshore. The CO2 fugacity (fCO2sw), calculated from total alkalinity (1,450 < TA < 2,394 μmol kg−1) and dissolved inorganic carbon (1,303 < DIC < 2,062 μmol kg−1) measurements, confirms that the Amazon River plume is a sink of atmospheric CO2 in areas with salinities <35 psu, whereas, in regions with salinities >35 and higher-intensity winds, the CO2 flux is reversed. Lower fCO2sw values were observed in the NECC area. The ΔfCO2 in this region was less than 5 μatm (−0.3 mmol m−2 d−1), while the ΔfCO2 in the coastal region was approximately 50 μatm (+3.7 mmol m−2 d−1). During the cruise, heterotrophic and autotrophic processes were observed and are indicative of the influences of terrestrial material and biological activity, respectively. PMID:28824554

Miocene oceanographic changes of the western equatorial Atlantic (Ceara Rise) based on calcareous dinoflagellate cysts

NASA Astrophysics Data System (ADS)

Heinrich, S.; Zonneveld, K. A. F.; Willems, H.

2010-09-01

The middle- and upper Miocene represent a time-interval of major changes in palaeoceanography that favoured the cooling of the climate and culminated in the Northern Hemisphere Glaciation (NHG). The basis for the development of the modern deepwater circulation pattern, e.g. thermohaline circulation, was hereby established. Tectonic events played a key role in the progressing Miocene oceanography, such as the narrowing of the Panama gateway (e.g. Duque-Caro 1990) and the possible linked changes in North Atlantic Deep Water formation (Lear et al. 2003). However, the complex interaction between the closing of the Panama Gateway, the development of NADW, and thus the oceanographic progression towards our present day circulation is far from being fully understood. We want to improve the understanding of these processes by establishing a detailed palaeoceanographic reconstruction of the western equatorial Atlantic Ocean on the basis of calcareous dinoflagellate cyst (dinocyst) associations. Within this study, we investigated sediment samples from ODP Site 926A by defining the calcareous dinocyst assemblage. Site 926A is located at the southwestern flank of the Ceara Rise, an area of highest sensitivity to global deep water circulation changes. At about 12 Ma, when NADW production increased (e.g. Wright et al. 1992), we see a distinct increase in the absolute abundances of the calcareous dinocysts. This might be related to enhanced productivity or to better carbonate preservation. At 11.3 Ma, Leonella granifera, a species known to be strongly related to terrestrial input occurs. This could be a signal for the initiation of the Amazon River as a transcontinental river with the development of the Amazon fan (11.8 - 11.3 Ma; Figueiredo et al. 2009) in relation to Andean tectonism. References: Duque-Caro, H. (1990): Neogene stratigraphy, paleoceanography and palebiology in Northwest South America and the evolution of the Panama Seaway. Palaeogeography, Palaeoclimatology, Palaeoecology 77, 203-234. Figueiredo, J., Hoorn, C., van der Veen, P., Soares, E. (2009): Late Miocene onset of the Amazon River and the Amazon deep-sea fan: Evidence from the Foz do Amazonas Basin. Geology; v. 37, no. 7; p. 619-622. Lear, C.H., Rosenthal, Y., Wright, J.D. (2003): The closing of a seaway: ocean water masses and global climate change. Earth and Planetary Science Letters 210, 425-436. Wright, J.D., Miller, K.G., Fairbanks, R.G. (1992): Early and middle Miocene stable isotopes: implications for deepwater circulation and climate. Paloceanography 7(3): 357-398.

What We Can Learn from Amazon for Clinical Decision Support Systems.

PubMed

Abid, Sidra; Keshavjee, Karim; Karim, Arsalan; Guergachi, Aziz

2017-01-01

Health care continue to lag behind other industries, such as retail and financial services, in the use of decision-support-like tools. Amazon is particularly prolific in the use of advanced predictive and prescriptive analytics to assist its customers to purchase more, while increasing satisfaction, retention, repeat-purchases and loyalty. How can we do the same in health care? In this paper, we explore various elements of the Amazon website and Amazon's data science and big data practices to gather inspiration for re-designing clinical decision support in the health care sector. For each Amazon element we identified, we present one or more clinical applications to help us better understand where Amazon's.

Insights into iron sources and pathways in the Amazon River provided by isotopic and spectroscopic studies

NASA Astrophysics Data System (ADS)

Mulholland, Daniel Santos; Poitrasson, Franck; Boaventura, Geraldo Resende; Allard, Thierry; Vieira, Lucieth Cruz; Santos, Roberto Ventura; Mancini, Luiz; Seyler, Patrick

2015-02-01

The present study investigated the weathering and transport mechanisms of Fe in the Amazon River. A particular emphasis was placed on Fe partitioning, speciation, and isotopic fractionation in the contrasting waters of the Solimões and Negro rivers and their mixing zone at the beginning of the Amazon River. Samples collected in the end-member rivers and thirteen sites distributed throughout the mixing zone were processed through frontal vacuum filtration and tangential-flow ultrafiltration to separate the different suspended solid fractions, i.e., particulate (P > 0.45 μm and P > 0.22 μm), colloidal (0.22 μm > C > 5 kDa) and truly dissolved elements (TD < 5 kDa). The Fe isotopic composition and electron paramagnetic resonance (EPR) species were measured on these different pore-sized fractions. The acidic and organo-Fe-rich waters of the Negro River displayed dissolved and colloidal fractions enriched in heavy isotopes (∼1.2‰, in δ57Fe values relative to IRMM-14), while the particulate fractions yielded light isotopic compositions of -0.344‰ for P > 0.22 μm and -0.104‰ for P > 0.45 μm fractions). The mineral particulate-rich waters of the Solimões River had dissolved and colloidal fractions with light isotopic composition (-0.532‰ and -0.176‰, respectively), whereas the particulate fractions yielded δ57Fe values close to those of the continental crust (i.e., -0.029‰ for P > 0.22 μm and 0.028‰ for P > 0.45 μm). Ten kilometers downstream from the Negro and Solimões junction, the concentrations of colloidal and dissolved Fe species deviate markedly from conservative mixing. A maximum Fe loss of 43 μg/L (i.e., 50% of the dissolved and colloidal Fe) is observed 110 km downstream from the rivers junction. The contrasting Negro and Solimões Rivers isotopic compositions along the pore-sized water fractions is attributable to the biogeochemical processes involving different types of upland soils and parental materials. For instance, the isotopic composition of colloidal and dissolved Fe from the Negro River are consistent with Fe oxidation and complexation mechanisms at the interface between waterlogged podzols and river networks, as supported by strong organo-Fe complexes signals observed by EPR. Conversely, the particulate and colloidal fractions from the Solimões River have δ57Fe consistent with strong mechanical erosion in the Andean Cordillera and upland soils, as evidenced by high concentrations of Fe3+-oxides sensu lato measured by EPR. The massive dissolved and colloidal Fe removal is associated with the evolution of the physical and chemical composition of the waters (i.e., ionic strength) during mixing, which influences organo-Fe3+ and Fe3+-oxyhydroxides stability. Several models are discussed to explain Fe non-conservative behavior, including dissociation of organo-Fe complexes and the subsequent formation of solid Fe3+-oxyhydroxides and semiquinone free radicals, as evidenced by EPR spectra demonstrating that organo-Fe signals decrease as Fe3+-oxyhydroxides and free radicals signals increase. As in estuarine regions, the mechanisms involving Fe transfer and loss in the mixing zone has a negligible effect on the bulk water Fe isotopic composition. This result suggests that a tropical basin similar to the Amazon River Basin delivers to the ocean waters with an Fe isotopic composition similar to that of the Earth's continental crust.

Ground-water provinces of Brazil

USGS Publications Warehouse

Schneider, Robert

1962-01-01

As part of a study of the status of investigations and development of ground water in Brazil, made under the auspices of the United States International Cooperation Administration and with the cooperation of the Government of Brazil, the country was divided into seven ground-water provinces. The identification and delineation of the provinces were based on the regional distribution of the dominant geologic units which are known or inferred to have distinctive water-bearing characteristics. Three of the provinces, covering most of the country, are underlain by Precambrian crystalline rocks. Three others coincide in part with four extensive sedimentary basins--the Parnaiba or Maranhfio basin and the contiguous Sao Francisco basin in the northeast and east, the Amazon basin in the north and northwest, and the Paranfi basin in the south and southwest. In addition, the narrow, discontinuous coastal plain is considered as a province. the occurrence of ground water is discussed briefly, and pertinent data are given on the more important aquifers, together with information on some existing wells. Because of the widespread distribution of crystalline rocks of low permeability, it is difficult in many areas to develop large or even adequate ground-water supplies. In general, satisfactory supplies of water are available in most of the rest of the country. Some problems include the relative deficiency of rainfall in the northeast together with the occurrence, in parts of this region, of mineralized water in the crystalline rocks. Also, there is a potential problem of excessive lowering of water levels and interference among wells in the intensively developed area of the city of Sao Paulo.

Modelling basin-wide variations in Amazon forest photosynthesis

NASA Astrophysics Data System (ADS)

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

2010-05-01

Given the importance of Amazon rainforest in the global carbon and hydrological cycles, there is a need to use parameterized and validated ecosystem gas exchange and vegetation models for this region in order to adequately simulate present and future carbon and water balances. Recent research has found major differences in above-ground net primary productivity (ANPP), above ground biomass and tree dynamics across Amazonia. West Amazonia is more dynamic, with younger trees, higher stem growth rates and lower biomass than central and eastern Amazon (Baker et al. 2004; Malhi et al. 2004; Phillips et al. 2004). A factor of three variation in above-ground net primary productivity has been estimated across Amazonia by Malhi et al. (2004). Different hypotheses have been proposed to explain the observed spatial variability in ANPP (Malhi et al. 2004). First, due to the proximity to the Andes, sites from western Amazonia tend to have richer soils than central and eastern Amazon and therefore soil fertility could possibly be highly related to the high wood productivity found in western sites. Second, if GPP does not vary across the Amazon basin then different patterns of carbon allocation to respiration could also explain the observed ANPP gradient. However since plant growth depends on the interaction between photosynthesis, transport of assimilates, plant respiration, water relations and mineral nutrition, variations in plant gross photosynthesis (GPP) could also explain the observed variations in ANPP. In this study we investigate whether Amazon GPP can explain variations of observed ANPP. We use a sun and shade canopy gas exchange model that has been calibrated and evaluated at five rainforest sites (Mercado et al. 2009) to simulate gross primary productivity of 50 sites across the Amazon basin during the period 1980-2001. Such simulation differs from the ones performed with global vegetation models (Cox et al. 1998; Sitch et al. 2003) where i) single plant functional type parameter values are assigned and assumed invariant with environmental condition but also ii) these models use leaf N as a factor that limit photosynthesis. Instead, since leaf P may also limit photosynthesis of the tropical forest (Reich et al. 2009), we use a more specific description of photosynthetic capacity across the basin based on the model evaluation done in Mercado et al. (2009) in which canopy photosynthetic capacity is related to foliar P but also using the relationships derived between canopy photosynthesis and leaf nutrients (N and P) from measurements in tropical trees (Domingues et al.In review). A study of this kind can inform the global vegetation/climate community as to the need for variability in key model parameters in order to accurately simulate carbon fluxes across the Amazon basin. Baker, T. R., et al. 2004. Increasing biomass in Amazonian forest plots. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences 359 (1443):353-365. Phillips, O. L. et al. 2004. Pattern and process in Amazon tree turnover, 1976-2001. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences 359 (1443):381-407. Malhi, Y. et al. 2004. The above-ground coarse wood productivity of 104 Neotropical forest plots. Global Change Biology 10 (5):563-591. Mercado, L.M. et al. 2009. Impact of changes in diffuse radiation on the global land carbon sink. Nature 458 (7241), 1014. Cox, P. M. et al. 1998. A canopy conductance and photosynthesis model for use in a GCM land surface scheme. Journal of Hydrology 213 (1-4):79-9 Sitch, S. et al. 2003. Evaluation of ecosystem dynamics, plant geography and terrestrial carbon cycling in the LPJ dynamic global vegetation model. Global Change Biology 9 (2):161-185. Reich B. R. et al. 2009. Leaf phosphorus influences the photosynhtesis-nitrogen relation: a cross-biome analysis of 314 species. Oecologia, doi 10.1007/s00442-009-1291-3. Domingues, T. et al. In review. Co-limitation of photosynthetic capacity by nitrogen and phosphorus along a precipitation gradient in West Africa. Plant Cell and Environment.

The Surface Water and Ocean Topography Satellite Mission - An Assessment of Swath Altimetry Measurements of River Hydrodynamics

NASA Technical Reports Server (NTRS)

Wilson, Matthew D.; Durand, Michael; Alsdorf, Douglas; Chul-Jung, Hahn; Andreadis, Konstantinos M.; Lee, Hyongki

2012-01-01

The Surface Water and Ocean Topography (SWOT) satellite mission, scheduled for launch in 2020 with development commencing in 2015, will provide a step-change improvement in the measurement of terrestrial surface water storage and dynamics. In particular, it will provide the first, routine two-dimensional measurements of water surface elevations, which will allow for the estimation of river and floodplain flows via the water surface slope. In this paper, we characterize the measurements which may be obtained from SWOT and illustrate how they may be used to derive estimates of river discharge. In particular, we show (i) the spatia-temporal sampling scheme of SWOT, (ii) the errors which maybe expected in swath altimetry measurements of the terrestrial surface water, and (iii) the impacts such errors may have on estimates of water surface slope and river discharge, We illustrate this through a "virtual mission" study for a approximately 300 km reach of the central Amazon river, using a hydraulic model to provide water surface elevations according to the SWOT spatia-temporal sampling scheme (orbit with 78 degree inclination, 22 day repeat and 140 km swath width) to which errors were added based on a two-dimension height error spectrum derived from the SWOT design requirements. Water surface elevation measurements for the Amazon mainstem as may be observed by SWOT were thereby obtained. Using these measurements, estimates of river slope and discharge were derived and compared to those which may be obtained without error, and those obtained directly from the hydraulic model. It was found that discharge can be reproduced highly accurately from the water height, without knowledge of the detailed channel bathymetry using a modified Manning's equation, if friction, depth, width and slope are known. Increasing reach length was found to be an effective method to reduce systematic height error in SWOT measurements.

The reactivity of plant-derived organic matter and the potential importance of priming effects along the lower Amazon River

NASA Astrophysics Data System (ADS)

Ward, Nicholas D.; Bianchi, Thomas S.; Sawakuchi, Henrique O.; Gagne-Maynard, William; Cunha, Alan C.; Brito, Daimio C.; Neu, Vania; de Matos Valerio, Aline; da Silva, Rodrigo; Krusche, Alex V.; Richey, Jeffrey E.; Keil, Richard G.

2016-06-01

Here we present direct measurements of the biological breakdown of 13C-labeled substrates to CO2 at seven locations along the lower Amazon River, from Óbidos to the mouth. Dark incubation experiments were performed at high and low water periods using vanillin, a lignin phenol derived from vascular plants, and at the high water period using four different 13C-labeled plant litter leachates. Leachates derived from oak wood were degraded most slowly with vanillin monomers, macrophyte leaves, macrophyte stems, and whole grass leachates being converted to CO2 1.2, 1.3, 1.7, and 2.3 times faster, respectively, at the upstream boundary, Óbidos. Relative to Óbidos, the sum degradation rate of all four leachates was 3.3 and 2.6 times faster in the algae-rich Tapajós and Xingu Rivers, respectively. Likewise, the leachates were broken down 3.2 times more quickly at Óbidos when algal biomass from the Tapajós River was simultaneously added. Leachate reactivity similarly increased from Óbidos to the mouth with leachates breaking down 1.7 times more quickly at Almeirim (midway to the mouth) and 2.8 times more quickly across the river mouth. There was no discernible correlation between in situ nutrient levels and remineralization rates, suggesting that priming effects were an important factor controlling reactivity along the continuum. Further, continuous measurements of CO2, O2, and conductivity along the confluence of the Tapajós and Amazon Rivers and the Xingu and Jarauçu Rivers revealed in situ evidence for enhanced O2 drawdown and CO2 production along the mixing zone of these confluences.

Integrating Disciplines, Sectors, and Societies to Improve the Definition and Implementation of Environmental Flows for Dammed Amazonian Rivers

NASA Astrophysics Data System (ADS)

Kaplan, D. A.; Livino, A.; Arias, M. E.; Crouch, T. D.; Anderson, E.; Marques, E.; Dutka-Gianelli, J.

2017-12-01

The Amazon River watershed is the world's largest river basin and provides US$30 billion/yr in ecosystem services to local populations, national societies, and humanity at large. The Amazon is also a relatively untapped source of hydroelectricity for Latin America, and construction of >30 large hydroelectric dams and >170 small dams is currently underway. Hydropower development will have a cascade of physical, ecological, and social effects at local to global scales. While Brazil has well-defined environmental impact assessment and mitigation programs, these efforts often fail to integrate data and knowledge across disciplines, sectors, and societies throughout the dam planning process. Resulting failures of science, policy, and management have had widespread environmental, economic, and social consequences, highlighting the need for an improved theoretical and practical framework for understanding the impacts of Amazon dams and guiding improved management that respects the needs and knowledge of diverse set of stakeholders. We present a conceptual framework that links four central goals: 1) connecting research in different disciplines (interdisciplinarity); 2) incorporating new knowledge into decision making (adaptive management); 3) including perspectives and participation of non-academic participants in knowledge generation (transdisciplinarity); and 4) extending the idea of environmental flows ("how much water does a river need?") to better consider human uses and users through the concept of fluvial anthropology ("how much water does a society need?"). We use this framework to identify opportunities for improved integration strategies within the (Brazilian) hydroelectric power plant planning and implementation "lifecycle." We applied this approach to the contentious Belo Monte dam, where compliance with regulatory requirements, including monitoring for environmental flows, exemplifies the opportunity for applying adaptive management, but also highlights an urgent need for much improved communication with and participation of affected communities.

Interannual Variation in Offshore Advection of Amazon-Orinoco Plume Waters: Observations, Forcing Mechanisms, and Impacts

NASA Astrophysics Data System (ADS)

Fournier, S.; Vandemark, D.; Gaultier, L.; Lee, T.; Jonsson, B.; Gierach, M. M.

2017-11-01

This study investigates sea surface salinity (SSS) and sea surface temperature (SST) variations in the tropical Atlantic east of the Lesser Antilles, a region where freshwater advection from the Amazon and Orinoco Rivers, may potentially impact air-sea interaction. Observations are used to document later-summer variability and evaluate offshore riverine transport from 2010 to 2014. During this period, the largest difference in plume-affected areas, defined as the extent covered by SSS lower than 35.5 pss, is found between 2011 and 2014. Plume waters covered 92% of the study region in 2011 and 60% in 2014, with the average SSS in the study region being 2 pss lower in 2011. Lagrangian particle tracking based on satellite-derived ocean currents is used to diagnose the impact of the river plumes on SSS and SST from 2010 to 2014. Northward freshwater flux in summer 2014 was significantly weaker than fluxes in 2010-2013. This difference is not due to interannual discharge variability, but to significant changes in eddy-driven transport and cross-shore winds. In particular, the stronger cross-shore wind in May 2014 restricted offshore freshwater flow and lead to a smaller plume-affected area. Persistent SST gradients are often found near the plume edge, which may have implications for ocean-atmosphere coupling associated with atmospheric convection. SST in the study region was 1°C higher in 2010 compared to other years, and is related to basin-scale ocean-atmosphere processes. Interannual variation in Amazon advective pathways and the associated SSS changes are also influenced by changes in the ITCZ position between 2011 and 2014.

Interannual Variation in Offshore Advection of Amazon-Orinoco Plume Waters: Observations, Forcing Mechanisms, and Impacts

NASA Astrophysics Data System (ADS)

Fournier, S.; Vandemark, D. C.; Gaultier, L.; Lee, T.; Jonsson, B. F.; Gierach, M. M.

2017-12-01

Sea surface salinity (SSS) and sea surface temperature (SST) variations in the tropical Atlantic east of the Lesser Antilles, a region impacted by freshwater advection from the Amazon and Orinoco Rivers have potential implications to late-summer tropical cyclones (TCs). This study examines these variations during late summer and their forcing mechanisms using observations. During the period 2010-2014, the largest difference in plume-affected area, defined as the extent covered by SSS lower than 35.5 pss, is found between 2011 and 2014. Plume waters covered 92% (60%) of the study region in 2011 (2014) with the averaged SSS in the study region being 2-pss lower in 2011. Lagrangian particle tracking based on satellite-derived ocean currents is used to diagnose the impacts of the river plumes on SSS and SST during 2010-2014. Northward freshwater flux in the summer of 2014 is significantly weaker than those in 2010-2013. This is not due to interannual discharge variability, but significant changes in eddy-driven transport and cross-shore winds. In particular, the stronger cross-shore wind in May 2014 restricted offshore freshwater flow, leading to a smaller extent of the plume-affected area. Persistent SST gradients are often found near the plume edge, which may have implication to ocean-atmosphere coupling associated with TC-related convection. SST in the study region is 1°C higher in 2010 than in other years, and is related to basin-scale ocean-atmosphere processes. Interannual variation in Amazon advective pathways and the associated SSS changes are also influenced by changes in the ITCZ position between 2011 and 2014.

Vulnerability of Amazon forests to storm-driven tree mortality

NASA Astrophysics Data System (ADS)

Negrón-Juárez, Robinson I.; Holm, Jennifer A.; Magnabosco Marra, Daniel; Rifai, Sami W.; Riley, William J.; Chambers, Jeffrey Q.; Koven, Charles D.; Knox, Ryan G.; McGroddy, Megan E.; Di Vittorio, Alan V.; Urquiza-Muñoz, Jose; Tello-Espinoza, Rodil; Alegria Muñoz, Waldemar; Ribeiro, Gabriel H. P. M.; Higuchi, Niro

2018-05-01

Tree mortality is a key driver of forest community composition and carbon dynamics. Strong winds associated with severe convective storms are dominant natural drivers of tree mortality in the Amazon. Why forests vary with respect to their vulnerability to wind events and how the predicted increase in storm events might affect forest ecosystems within the Amazon are not well understood. We found that windthrows are common in the Amazon region extending from northwest (Peru, Colombia, Venezuela, and west Brazil) to central Brazil, with the highest occurrence of windthrows in the northwest Amazon. More frequent winds, produced by more frequent severe convective systems, in combination with well-known processes that limit the anchoring of trees in the soil, help to explain the higher vulnerability of the northwest Amazon forests to winds. Projected increases in the frequency and intensity of convective storms in the Amazon have the potential to increase wind-related tree mortality. A forest demographic model calibrated for the northwestern and the central Amazon showed that northwestern forests are more resilient to increased wind-related tree mortality than forests in the central Amazon. Our study emphasizes the importance of including wind-related tree mortality in model simulations for reliable predictions of the future of tropical forests and their effects on the Earth’ system.

Hydraulic characterization of the middle reach of the Congo River

NASA Astrophysics Data System (ADS)

O'Loughlin, F.; Trigg, M. A.; Schumann, G. J.-P.; Bates, P. D.

2013-08-01

The middle reach of the Congo remains one of the most difficult places to access, with ongoing conflicts and a lack of infrastructure. This has resulted in the Congo being perhaps the least understood large river hydraulically, particularly compared to the Amazon, Nile, or Mississippi. Globally the Congo River is important; it is the largest river in Africa and the basin contains some of the largest areas of tropical forests and wetlands in the world, which are important to both the global carbon and methane cycles. This study produced the first detailed hydraulic characterization of the middle reach, utilizing mostly remotely sensed data sets. Using Landsat imagery, a 30 m resolution water-mask was created for the middle reach, from which effective river widths and the number of channels and islands were determined. Water surface slopes were determined using ICESat observations for three different periods during the annual flood pulse, and while the overall slope calculated was similar to previous estimates, greater spatial variability was identified. We find that the water surface slope varies markedly in space but relatively little in time and that this appears to contrast with the Amazon where previous studies indicate that time and spatial variations are of equal magnitude. Five key hydraulic constraints were also identified, which play an important role in the overall dynamics of the Congo. Finally, backwater lengths were approximated for four of these constraints, with the results showing that at high water, over a third of the middle reach is affected by backwater effects.

Brazilian Amazon Roads and Parks: Temporal & Spatial Deforestation Dynamics

NASA Astrophysics Data System (ADS)

Pfaff, A.; Robalino, J.

2011-12-01

Heterogeneous Forest Impacts of Transport Infrastructure: spatial frontier dynamics & impacts of Brazilian Amazon road changes Prior research on road impacts has almost completely ignored heterogeneity of impacts and as a result both empirically understated potential impact and missed policy potential. We note von Thunen's model suggests not only heterogeneity with distance from market but also specifically road impacts rising then falling with distance ('non-monoThunicity') Endogenous development and partial adjustment dynamics support this for the short run. Causal effects result from studying Brazilian Amazon deforestation (1976-87, 2000-04) using matching for short-run responses to lagged new roads changes (1968-75, 1985-00). We show the critical role of prior development, proxied by 1968 and 1985 road distances, for which exact matching addresses development trends and transforms impact estimates. Splitting the sample on this measure finds confirmation of the nonmonotonic predictions: new road impacts are relatively low if a prior road was close, such that prior transport access and endogenous development dynamics compete with the new road for influence, but also if a prior road was far, since first-decade adjustment in pristine areas is limited; yet in between these bounds, investments immediately raise deforestation significantly. This pattern helps to explain lower estimates within research on a single average impact. It suggests potential for REDD if a country chooses to shift its spatial transport networks. Protected Areas & Brazilian Amazon Deforestation: modeling and testing the impacts of varied PA strategies We model and then estimate the impacts of multiple types of protected areas upon 2000 - 2004 deforestation in the Brazilian Amazon. Our modeling starts with federal versus state objectives and predicts differences in both choice and implementation of each PA strategy that we examine. Our empirical examination brings not only breakdowns sufficient to test the model's implications but also, critically, explicit controls for the influences of the characteristics of protected lands. Controlling for how PAs differ from unprotected lands cuts impact estimates roughly in half, implying that accounting for and planning around site characteristics should be a part of REDD. For instance, we highlight differences among the improved impacts estimates across PA subsets: Federal vs. State vs. Indigenous; 1980s vs. 1990s; and Integral Protection vs. Sustainable Use. Without correcting for the differences in land characteristics, each of the subsets we examine is estimated to cause significant reduction in deforestation. Corrections find Federal and Indigenous prevented more clearing than did State, while Sustainable Use areas blocked more deforestation than Integral Protection. The reason for these unequal shifts in estimates is that the different PA subsets were allocated to different types of locations. That protection's impact is not uniform is important for REDD and those designing institutions should note what local planners may favor.

Trypanosoma cruzi strain TcI is associated with chronic Chagas disease in the Brazilian Amazon.

PubMed

Santana, Rosa Amélia Gonçalves; Magalhães, Laylah Kelre Costa; Magalhães, Laise Kelman Costa; Prestes, Suzane Ribeiro; Maciel, Marcel Gonçalves; da Silva, George Allan Villarouco; Monteiro, Wuelton Marcelo; de Brito, Felipe Rocha; de Aguiar Raposo Câmara Coelho, Leila Inês; Barbosa-Ferreira, João Marcos; Guerra, Jorge Augusto Oliveira; Silveira, Henrique; das Graças Vale Barbosa, Maria

2014-06-11

Chagas disease in the Amazon region is considered an emerging anthropozoonosis with a predominance of the discrete typing units (DTUs) TcI and TcIV. These DTUs are responsible for cases of acute disease associated with oral transmission. Chronic disease cases have been detected through serological surveys. However, the mode of transmission could not be determined, or any association of chronic disease with a specific T. cruzi DTU's. The aim of this study was to characterize Trypanosoma cruzi in patients with chronic Chagas disease in the State of Amazonas, Brazil. Blood culture and xenodiagnosis were performed in 36 patients with positive serology for Chagas disease who participated in a serological survey performed in urban and rural areas of Manaus, Amazonas. DNA samples were extracted from the feces of triatomines used for xenodiagnosis, and the nontranscribed spacer of the mini-exon gene and the mitochondrial gene cytochrome oxidase subunit II (COII) were amplified by PCR and sequenced. Blood culture and xenodiagnosis were negative in 100% of samples; however, molecular techniques revealed that in 13 out of 36 (36%) fecal samples from xenodiagnosis, T. cruzi was characterized as the DTU TcI, and different haplotypes were identified within the same DTU. The DTU TcI, which is mainly associated with acute cases of Chagas disease in the Amazon region, is also responsible for chronic infection in patients from a region in the State of Amazonas.

Trypanosoma cruzi strain TcI is associated with chronic Chagas disease in the Brazilian Amazon

PubMed Central

2014-01-01

Background Chagas disease in the Amazon region is considered an emerging anthropozoonosis with a predominance of the discrete typing units (DTUs) TcI and TcIV. These DTUs are responsible for cases of acute disease associated with oral transmission. Chronic disease cases have been detected through serological surveys. However, the mode of transmission could not be determined, or any association of chronic disease with a specific T. cruzi DTU’s. The aim of this study was to characterize Trypanosoma cruzi in patients with chronic Chagas disease in the State of Amazonas, Brazil. Methods Blood culture and xenodiagnosis were performed in 36 patients with positive serology for Chagas disease who participated in a serological survey performed in urban and rural areas of Manaus, Amazonas. DNA samples were extracted from the feces of triatomines used for xenodiagnosis, and the nontranscribed spacer of the mini-exon gene and the mitochondrial gene cytochrome oxidase subunit II (COII) were amplified by PCR and sequenced. Results Blood culture and xenodiagnosis were negative in 100% of samples; however, molecular techniques revealed that in 13 out of 36 (36%) fecal samples from xenodiagnosis, T. cruzi was characterized as the DTU TcI, and different haplotypes were identified within the same DTU. Conclusion The DTU TcI, which is mainly associated with acute cases of Chagas disease in the Amazon region, is also responsible for chronic infection in patients from a region in the State of Amazonas. PMID:24916362

Distribution of phlebotomine sand fly genotypes (Lutzomyia shannoni, Diptera: Psychodidae) across a highly heterogeneous landscape.

PubMed

Mukhopadhyay, J; Ghosh, K; Ferro, C; Munstermann, L E

2001-03-01

Genetic variability of eight Colombian field populations and two laboratory colonies of a tropical forest sand fly, Lutzomyia shannoni Dyar, was assessed by comparing allozyme frequencies at 20 enzyme loci. Substantial genetic variability was noted in all strains, with mean heterozygosities of 13-21% and alleles per locus of 2.0-2.8. Four loci were monomorphic. Six populations in north and central Colombia showed close genetic similarity (Nei's distances, 0.01-0.09), despite mountainous environment, discontinuous forest habitat, and elevation differences from 125 to 1,220 m. Two samples representing the Orinoco (near Villavicencio) and Amazon (near Leticia) river basins were similar (Nei's distance, 0.08) but diverged substantially from the central six samples (Nei's distances, 0.26-0.40). Although the range of L. shannoni extends from the southeastern United States to northern Argentina, three genetically distinct, geographically discrete, groups were discerned by the current analysis: Orinoco-Amazon river basins, north-central Colombia, and eastern United States.

First description of Leishmania (Viannia) infection in Evandromyia saulensis, Pressatia sp. and Trichophoromyia auraensis (Psychodidae: Phlebotominae) in a transmission area of cutaneous leishmaniasis in Acre state, Amazon Basin, Brazil.

PubMed

Araujo-Pereira, Thais de; Pita-Pereira, Daniela de; Boité, Mariana Côrtes; Melo, Myllena; Costa-Rego, Taiana Amancio da; Fuzari, Andressa Alencastre; Brazil, Reginaldo Peçanha; Britto, Constança

2017-01-01

Studies on the sandfly fauna to evaluate natural infection indexes are still limited in the Brazilian Amazon, a region with an increasing incidence of cutaneous leishmaniasis. Here, by using a multiplex polymerase chain reaction directed to Leishmania kDNA and hybridisation, we were able to identify L. (Viannia) subgenus in 12 out of 173 sandflies captured in the municipality of Rio Branco, Acre state, revealing a positivity of 6.94%. By sequencing the Leishmania 234 bp-hsp70 amplified products from positive samples, infection by L. (V.) braziliensis was confirmed in five sandflies: one Evandromyia saulensis, three Trichophoromyia auraensis and one Pressatia sp. The finding of L. (Viannia) DNA in two Ev. saulensis corresponds to the first record of possible infection associated with this sandfly. Moreover, our study reveals for the first time in Brazil, Th. auraensis and Pressatia sp. infected by L. (Viannia) parasites.

First description of Leishmania (Viannia) infection in Evandromyia saulensis, Pressatia sp. and Trichophoromyia auraensis (Psychodidae: Phlebotominae) in a transmission area of cutaneous leishmaniasis in Acre state, Amazon Basin, Brazil

PubMed Central

de Araujo-Pereira, Thais; de Pita-Pereira, Daniela; Boité, Mariana Côrtes; Melo, Myllena; da Costa-Rego, Taiana Amancio; Fuzari, Andressa Alencastre; Brazil, Reginaldo Peçanha; Britto, Constança

2017-01-01

Studies on the sandfly fauna to evaluate natural infection indexes are still limited in the Brazilian Amazon, a region with an increasing incidence of cutaneous leishmaniasis. Here, by using a multiplex polymerase chain reaction directed to Leishmania kDNA and hybridisation, we were able to identify L. (Viannia) subgenus in 12 out of 173 sandflies captured in the municipality of Rio Branco, Acre state, revealing a positivity of 6.94%. By sequencing the Leishmania 234 bp-hsp70 amplified products from positive samples, infection by L. (V.) braziliensis was confirmed in five sandflies: one Evandromyia saulensis, three Trichophoromyia auraensis and one Pressatia sp. The finding of L. (Viannia) DNA in two Ev. saulensis corresponds to the first record of possible infection associated with this sandfly. Moreover, our study reveals for the first time in Brazil, Th. auraensis and Pressatia sp. infected by L. (Viannia) parasites. PMID:28076470

Unofficial Road Building in the Amazon: Socioeconomic and Biophysical Explanations

NASA Technical Reports Server (NTRS)

Perz, Stephen G.; Caldas, Marcellus M.; Arima, Eugenio; Walker, Robert J.

2007-01-01

Roads have manifold social and environmental impacts, including regional development, social conflicts and habitat fragmentation. 'Road ecology' has emerged as an approach to evaluate the various ecological and hydrological impacts of roads. This article aims to complement road ecology by examining the socio-spatial processes of road building itself. Focusing on the Brazilian Amazon, a heavily-studied context due to forest fragmentation by roads, the authors consider non-state social actors who build 'unofficial roads' for the purpose of gaining access to natural resources to support livelihoods and community development. They examine four case studies of roads with distinct histories in order to explain the socio-spatial processes behind road building in terms of profit maximization, land tenure claims, co-operative and conflictive political ecologies, and constraints as well as opportunities afforded by the biophysical environment. The study cases illustrate the need for a multi-pronged theoretical approach to understanding road building, and call for more attention to the role of non-state actors in unofficial road construction.

Rhinovirus antibodies in an isolated Amazon Indian tribe.

PubMed

Thwing, C J; Arruda, E; Vieira Filho, J P; Castelo Filho, A; Gwaltney, J M

1993-06-01

In early 1985, the Parakana-Apiterewa, a small, primitive Indian tribe, was contacted in the southern Amazon Basin. The tribe was thought to have been totally isolated from civilization until recent development of their land. Blood specimens were collected in 1985, shortly after the discovery of the tribe, and analyzed for the presence of rhinovirus-neutralizing antibody to nine different immunotypes. Six to forty-seven percent of the serum samples tested contained antibody to at least one immunotype of rhinovirus. The prevalence of rhinovirus antibody in the Parakana-Apiterewa Indians was similar to that reported in United States populations, suggesting that there had been considerable direct or indirect contact in the past between tribe members and persons in the outside world.

On the Sensitivity of the Diurnal Cycle in the Amazon to Convective Intensity

NASA Technical Reports Server (NTRS)

Itterly, Kyle; Taylor, Patrick

2015-01-01

This presentation uses publicly available CERES and radiosonde data to investigate the sensitivity of thetropical convective diurnal cycle to atmosphere state. Averaging surface observations into regimes of convective intensitydefined by satellite shows great promise for physical understandingof convection.• Convective processes in the Amazon are highly variable seasonallyand locally.• Buoyancy/CIN more important JJA– Mesoscale/synoptic features easier to separate– Length/depth of buoyancy layer very important in DJF (EL).• Moisture more important DJF, esp. UTH– Humidity of lower atmosphere significantly impacts LTS, LCL and abilityfor parcels to reach LFC.• Lower level jet strength/direction important• Convective initiation correlated with LTS, LR, LTH, EL• Duration/Phase better correlated with humidity variables• Surface Flux amplitude well correlated with convection

ERS-ENVISAT radar altimetry over the Amazon basin

NASA Astrophysics Data System (ADS)

Santos da Silva, J.; Calmant, S.; Rotunno Filho, O. C.; Seyler, F.; Mansur, W. J.; Cochonneau, G.

2009-12-01

Since the launch of satellite embarking radar altimeters in the late 80’s, scientists have investigated the feasibility of using these ocean-dedicated data over the continental waters. In fact, satellite radar altimetry is being recognized as a powerful tool to obtain time series of water stage consistent to those obtained by conventional in situ gauge stations. In addition, this technology has been proved to provide reliable information about the dynamics of large water bodies such as lakes and inner seas. However, the results should be deeply examined as we shift the analysis to water levels acquired during satellite crosses over rivers. Yet, hydrologists are still reluctant in using these data, as neither the neces¬sary time sampling nor accuracy is achieved, leading to endless debates in specialized workshops. Noteworthy to highlight, few published studies are dedicated to an in depth assessment of the radar altimetry over rivers, in¬cluding comparisons with water levels at fluviometric gauges. In this work, we present an extensive analysis of the quality of times series of river stages that we have constructed in the Amazon basin for a variety of water bodies such as large rivers, narrow stems, lakes and flooded areas using radar altimeters embarked on¬board ERS-2 and ENVISAT. The approach includes the sensitivity to the raw data processing methodology such as the tracking algorithm, the data selection at the crossings between satellite track and river bed (so-called virtual stations) and correction for off-nadir effects. The VALS toolbox was developed to process altimetry data at virtual stations under the framework of this study. Results of internal validation at cross-overs and external validation by comparison with in situ gauges are presented.

Optical Remote Sensing Algorithm Validation using High-Frequency Underway Biogeochemical Measurements in Three Large Global River Systems

NASA Astrophysics Data System (ADS)

Kuhn, C.; Richey, J. E.; Striegl, R. G.; Ward, N.; Sawakuchi, H. O.; Crawford, J.; Loken, L. C.; Stadler, P.; Dornblaser, M.; Butman, D. E.

2017-12-01

More than 93% of the world's river-water volume occurs in basins impacted by large dams and about 43% of river water discharge is impacted by flow regulation. Human land use also alters nutrient and carbon cycling and the emission of carbon dioxide from inland reservoirs. Increased water residence times and warmer temperatures in reservoirs fundamentally alter the physical settings for biogeochemical processing in large rivers, yet river biogeochemistry for many large systems remains undersampled. Satellite remote sensing holds promise as a methodology for responsive regional and global water resources management. Decades of ocean optics research has laid the foundation for the use of remote sensing reflectance in optical wavelengths (400 - 700 nm) to produce satellite-derived, near-surface estimates of phytoplankton chlorophyll concentration. Significant improvements between successive generations of ocean color sensors have enabled the scientific community to document changes in global ocean productivity (NPP) and estimate ocean biomass with increasing accuracy. Despite large advances in ocean optics, application of optical methods to inland waters has been limited to date due to their optical complexity and small spatial scale. To test this frontier, we present a study evaluating the accuracy and suitability of empirical inversion approaches for estimating chlorophyll-a, turbidity and temperature for the Amazon, Columbia and Mississippi rivers using satellite remote sensing. We demonstrate how riverine biogeochemical measurements collected at high frequencies from underway vessels can be used as in situ matchups to evaluate remotely-sensed, near-surface temperature, turbidity, chlorophyll-a derived from the Landsat 8 (NASA) and Sentinel 2 (ESA) satellites. We investigate the use of remote sensing water reflectance to infer trophic status as well as tributary influences on the optical characteristics of the Amazon, Mississippi and Columbia rivers.

Mapping Palm Swamp Wetland Ecosystems in the Peruvian Amazon: a Multi-Sensor Remote Sensing Approach

NASA Astrophysics Data System (ADS)

Podest, E.; McDonald, K. C.; Schroeder, R.; Pinto, N.; Zimmerman, R.; Horna, V.

2012-12-01

Wetland ecosystems are prevalent in the Amazon basin, especially in northern Peru. Of specific interest are palm swamp wetlands because they are characterized by constant surface inundation and moderate seasonal water level variation. This combination of constantly saturated soils and warm temperatures year-round can lead to considerable methane release to the atmosphere. Because of the widespread occurrence and expected sensitivity of these ecosystems to climate change, it is critical to develop methods to quantify their spatial extent and inundation state in order to assess their carbon dynamics. Spatio-temporal information on palm swamps is difficult to gather because of their remoteness and difficult accessibility. Spaceborne microwave remote sensing is an effective tool for characterizing these ecosystems since it is sensitive to surface water and vegetation structure and allows monitoring large inaccessible areas on a temporal basis regardless of atmospheric conditions or solar illumination. We developed a remote sensing methodology using multi-sensor remote sensing data from the Advanced Land Observing Satellite (ALOS) Phased Array L-Band Synthetic Aperture Radar (PALSAR), Shuttle Radar Topography Mission (SRTM) DEM, and Landsat to derive maps at 100 meter resolution of palm swamp extent and inundation based on ground data collections; and combined active and passive microwave data from AMSR-E and QuikSCAT to derive inundation extent at 25 kilometer resolution on a weekly basis. We then compared information content and accuracy of the coarse resolution products relative to the high-resolution datasets. The synergistic combination of high and low resolution datasets allowed for characterization of palm swamps and assessment of their flooding status. This work has been undertaken partly within the framework of the JAXA ALOS Kyoto & Carbon Initiative. PALSAR data have been provided by JAXA. Portions of this work were carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Strengthening Adaptation to Extreme Climate Events in Southwestern Amazonia: an Example from the Trinational Acre River Basin in the Madre de Dios/Peru - Acre/Brazil - Pando/Bolivia (MAP) Region.

NASA Astrophysics Data System (ADS)

Brown, I. F.

2015-12-01

Southwestern Amazonia, where Bolivia, Brazil and Peru meet, faces numerous challenges to the sustainable utilization of land and water resources as the region experiences rapid population and economic growth, expanding agriculture, transportation and energy sectors, along with frequent flooding and droughts. It is also predicted to be one of the most susceptible areas for climate change in the coming decade. The Acre River Basin, one of the few trinational basins in Amazonia, lies at the center of the Madre de Dios Region (Peru), Acre State (Brazil) and Pando Department (Bolivia) or MAP Region. It covers approximately 7,500 km2 and its inhabitants range from indigenous groups avoiding contact with industrial society to more than 60,000 dwellers of a binational urban center. The basin incorporates most the challenges facing the region and this paper discusses steps underway to address the basin's vulnerability to climate-related threats. A trinational group of professionals used GIS databases and local knowledge to classify these threats and possible societal responses. To prioritize threats and to propose responses, this group adapted a method proposed by the Queensland Climate Change Centre of Excellence of Australia to develop climate risk matrices for assessing impacts, adaptation, risk and vulnerability. The three priority climate variables were prolonged and more frequent droughts, more intense flooding, and more days with temperatures > 35oC. The final matrix proposed two areas of concentration - 1) Reduce the vulnerability of communities to hydro-meteorological extreme events and 2) Protect and restore ecosystems that maintain critical water-related resources with actions in public policy, capacity-building, and immediate activities. These results are being incorporated into the Amazon Project of the Global Environment Fund of the United Nations Environment Program, administered by the Amazon Cooperation Treaty Organization (ACTO).

Molecular characterization of an earliest cacao (Theobroma cacao L.) collection from Peruvian Amazon using microsatllite DNA markers

USDA-ARS?s Scientific Manuscript database

Cacao (Theobroma cacao L.) is indigenous to the Amazon region of South America. The Peruvian Amazon harbors a large number of diverse cacao populations. Since the 1930s, several numbers of populations have been collected from the Peruvian Amazon and maintained as ex situ germplasm repositories in ...

Reconstruction of the Amazon Basin effective moisture availability over the past 14,000 years.

PubMed

Maslin, M A; Burns, S J

2000-12-22

Quantifying the moisture history of the Amazon Basin is essential for understanding the cause of rain forest diversity and its potential as a methane source. We reconstructed the Amazon River outflow history for the past 14,000 years to provide a moisture budget for the river drainage basin. The oxygen isotopic composition of planktonic foraminifera recovered from a marine sediment core in a region of Amazon River discharge shows that the Amazon Basin was extremely dry during the Younger Dryas, with the discharge reduced by at least 40% as compared with that of today. After the Younger Dryas, a meltwater-driven discharge event was followed by a steady increase in the Amazon Basin effective moisture throughout the Holocene.

Neogene sharks and rays from the Brazilian 'Blue Amazon'.

PubMed

Aguilera, Orangel; Luz, Zoneibe; Carrillo-Briceño, Jorge D; Kocsis, László; Vennemann, Torsten W; de Toledo, Peter Mann; Nogueira, Afonso; Amorim, Kamilla Borges; Moraes-Santos, Heloísa; Polck, Marcia Reis; Ruivo, Maria de Lourdes; Linhares, Ana Paula; Monteiro-Neto, Cassiano

2017-01-01

The lower Miocene Pirabas Formation in the North of Brazil was deposited under influence of the proto-Amazon River and is characterized by large changes in the ecological niches from the early Miocene onwards. To evaluate these ecological changes, the elasmobranch fauna of the fully marine, carbonate-rich beds was investigated. A diverse fauna with 24 taxa of sharks and rays was identified with the dominant groups being carcharhiniforms and myliobatiforms. This faunal composition is similar to other early Miocene assemblages from the proto-Carribbean bioprovince. However, the Pirabas Formation has unique features compared to the other localities; being the only Neogene fossil fish assemblage described from the Atlantic coast of Tropical Americas. Phosphate oxygen isotope composition of elasmobranch teeth served as proxies for paleotemperatures and paleoecology. The data are compatible with a predominantly tropical marine setting with recognized inshore and offshore habitats with some probable depth preferences (e.g., Aetomylaeus groups). Paleohabitat of taxa particularly found in the Neogene of the Americas (†Carcharhinus ackermannii, †Aetomylaeus cubensis) are estimated to have been principally coastal and shallow waters. Larger variation among the few analyzed modern selachians reflects a larger range for the isotopic composition of recent seawater compared to the early Miocene. This probably links to an increased influence of the Amazon River in the coastal regions during the Holocene.

Earth Observation taken by the Expedition 20 crew

NASA Image and Video Library

2009-10-06

ISS020-E-047807 (6 Oct. 2009) --- Thunderstorms on the Brazilian horizon are featured in this image photographed by an Expedition 20 crew member on the International Space Station. A picturesque line of thunderstorms and numerous circular cloud patterns filled the view as the station crew members looked out at the limb and atmosphere (blue line on the horizon) of Earth. This region displayed in the photograph (top) includes an unstable, active atmosphere forming a large area of cumulonimbus clouds in various stages of development. The crew was looking west southwestward from the Amazon Basin, along the Rio Madeira, toward Bolivia when the image was taken. The distinctive circular patterns of the clouds in this view are likely caused by the aging of thunderstorms. Such ring structures often form during the final stages of a storm?s development as their centers collapse. Sunglint is visible on the waters of the Rio Madeira and Lago Acara in the Amazon Basin. Widespread haze over the basin gives the reflected light an orange hue. The Rio Madeira flows northward and joins the Amazon River on its path to the Atlantic Ocean. Scientists believe that a large smoke plume near the bottom center of the image may explain one source of the haze.

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

NASA Astrophysics Data System (ADS)

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

2014-06-01

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

Modeling seasonal and interannual variability in ecosystem carbon cycling for the Brazilian Amazon region

NASA Astrophysics Data System (ADS)

Potter, Christopher; Klooster, Steven; de Carvalho, Claudio Reis; Genovese, Vanessa Brooks; Torregrosa, Alicia; Dungan, Jennifer; Bobo, Matthew; Coughlan, Joseph

2001-05-01

Previous field measurements have implied that undisturbed Amazon forests may represent a substantial terrestrial sink for atmospheric carbon dioxide. We investigated this hypothesis using a regional ecosystem model for net primary production (NPP) and soil biogeochemical cycling. Seasonal and interannual controls on net ecosystem production (NEP) were studied with integration of high-resolution (8-km) multiyear satellite data to characterize Amazon land surface properties over time. Background analysis of temporal and spatial relationships between regional rainfall patterns and satellite observations (for vegetation land cover, fire counts, and smoke aerosol effects) reveals several notable patterns in the model driver data. Autocorrelation analysis for monthly vegetation "greenness" index (normalized difference vegetation index, NDVI) from the advanced very high resolution radiometer (AVHRR) and monthly rainfall indicates a significant lag time correlation of up to 12 months. At lag times approaching 36 months, autocorrelation function (ACF) values did not exceed the 95% confidence interval at locations west of about 47°W, which is near the transition zone of seasonal tropical forest and other (nonforest) vegetation types. Even at lag times of 12 months or less, the location near Manaus (approximately 60°W) represents the farthest western point in the Amazon region where seasonality of rainfall accounts significantly for monthly variations in forest phenology, as observed using NDVI. Comparisons of NDVI seasonal profiles in areas of the eastern Amazon widely affected by fires (as observed from satellite) suggest that our adjusted AVHRR-NDVI captures year-to-year variation in land cover greenness with minimal interference from small fires and smoke aerosols. Ecosystem model results using this newly generated combination of regional forcing data from satellite suggest that undisturbed Amazon forests can be strong net sinks for atmospheric carbon dioxide, particularly during wet (non El Niño) years. However, drought effects during El Niño years can reduce NPP in primary forests of the eastern Amazon by 10-20%, compared to long-term average estimates of regional productivity. Annual NEP for the region is predicted to range from -0.4 Pg C yr-1 (net CO2 source) to 0.5 Pg C yr-1 (net CO2 sink), with large interannual variability over the states of Pará, Maranhao, and Amazonas. As in the case of predicted NPP, it appears that periods of relatively high solar surface irradiance combined with several months of adequate rainfall are required to sustain the forest carbon sink for positive yearly NEP estimates.

SeReNA Project: studying aerosol interactions with cloud microphysics in the Amazon Basin

NASA Astrophysics Data System (ADS)

Correia, A. L.; Catandi, P. B.; Frigeri, F. F.; Ferreira, W. C.; Martins, J.; Artaxo, P.

2012-12-01

Cloud microphysics and its interaction with aerosols is a key atmospheric process for weather and climate. Interactions between clouds and aerosols can impact Earth's radiative balance, its hydrological and energetic cycles, and are responsible for a large fraction of the uncertainty in climatic models. On a planetary scale, the Amazon Basin is one of the most significant land sources of moisture and latent heat energy. Moreover, every year this region undergoes mearked seasonal shifts in its atmospheric state, transitioning from clean to heavily polluted conditions due to the occurrence of seasonal biomass burning fires, that emit large amounts of smoke to the atmosphere. These conditions make the Amazon Basin a special place to study aerosol-cloud interactions. The SeReNA Project ("Remote sensing of clouds and their interaction with aerosols", from the acronym in Portuguese, @SerenaProject on Twitter) is an ongoing effort to experimentally investigate the impact of aerosols upon cloud microphysics in Amazonia. Vertical profiles of droplet effective radius of water and ice particles, in single convective clouds, can be derived from measurements of the emerging radiation on cloud sides. Aerosol optical depth, cloud top properties, and meteorological parameters retrieved from satellites will be correlated with microphysical properties derived for single clouds. Maps of cloud brightness temperature will allow building temperature vs. effective radius profiles for hydrometeors in single clouds. Figure 1 shows an example extracted from Martins et al. (2011), illustrating a proof-of-concept for the kind of result expected within the framework for the SeReNA Project. The results to be obtained will help foster the quantitative knowledge about interactions between aerosols and clouds in a microphysical level. These interactions are a fundamental process in the context of global climatic changes, they are key to understanding basic processes within clouds and how aerosols can influence them. Reference: Martins et al. (2011) ACP, v.11, p.9485-9501. Available at: http://bit.ly/martinspaper Figure 1. Brightness temperature (left panel) and thermodynamic phase (right) of hydrometeors in the convective cloud shown in the middle panel. Extracted from Martins et al. (2011).

A comparison of extreme rainfall characteristics in the Brazilian Amazon derived from two gridded data sets and a national rain gauge network

NASA Astrophysics Data System (ADS)

Clarke, Robin T.; Bulhoes Mendes, Carlos Andre; Costa Buarque, Diogo

2010-07-01

Two issues of particular importance for the Amazon watershed are: whether annual maxima obtained from reanalysis and raingauge records agree well enough for the former to be useful in extending records of the latter; and whether reported trends in Amazon annual rainfall are reflected in the behavior of annual extremes in precipitation estimated from reanalyses and raingauge records. To explore these issues, three sets of daily precipitation data (1979-2001) from the Brazilian Amazon were analyzed (NCEP/NCAR and ERA-40 reanalyses, and records from the raingauge network of the Brazilian water resources agency - ANA), using the following variables: (1) mean annual maximum precipitation totals, accumulated over one, two, three and five days; (2) linear trends in these variables; (3) mean length of longest within-year "dry" spell; (4) linear trends in these variables. Comparisons between variables obtained from all three data sources showed that reanalyses underestimated time-trends and mean annual maximum precipitation (over durations of one to five days), and the correlations between reanalysis and spatially-interpolated raingauge estimates were small for these two variables. Both reanalyses over-estimated mean lengths of dry period relative to the mean length recorded by the raingauge network. Correlations between the trends calculated from all three data sources were small. Time-trends averaged over the reanalysis grid-squares, and spatially-interpolated time trends from raingauge data, were all clustered around zero. In conclusion, although the NCEP/NCAR and ERA-40 gridded data-sets may be valuable for studies of inter-annual variability in precipitation totals, they were found to be inappropriate for analysis of precipitation extremes.

Disease Vector Ecology Profile: Ecuador

DTIC Science & Technology

1998-12-01

fleas, has not been reported since 1985; however, extensive outbreaks in neighboring Peru occurred in 1992-94. Avoid rodent -infested areas and use PPM...throughout the year ( Peru ). Heavy shade in permanent bodies of water with abundant floatage. Commonly bites humans but apparently prefers rodents ...Vectors of Arboviruses other than Dengue or Yellow Fever in the Amazon Basin and Associated Northwestern Regions of South America

Detecting leaf phenology of seasonally moist tropical forests in South America with multi-temporal MODIS images.

Treesearch

Xiangming Xiao; Stephen Hagen; Qingyuan Zhang; Michael Keller; Berrien Moore III

2006-01-01

Leaf phenology of tropical evergreen forests affects carbon and water fluxes. In an earlier study of a seasonally moist evergreen tropical forest site in the Amazon basin, time series data of Enhanced Vegetation Index (EVI) from the VEGETATION and Moderate Resolution Imaging Spectroradiometer (MODIS) sensors showed an unexpected seasonal pattern, with higher EVI in the...

Automatic Calibration of Global Flow Routing Model Parameters in the Amazon Basin Using Virtual SWOT Data

NASA Astrophysics Data System (ADS)

Mouffe, Melodie; Getirana, Augusto; Ricci, Sophie; Lion, Christine; Biancamaria, Sylvian; Boone, Aaron; Mognard, Nelly; Rogel, Philippe

2013-09-01

The Surface Water and Ocean Topography (SWOT) wide swath altimetry mission will provide measurements of water surface elevations (WSE) at a global scale. The aim of this study is to investigate the potential of these satellite data for the calibration of the hydrological model HyMAP, over the Amazon river basin. Since SWOT has not yet been launched, synthetical observations are used to calibrate the river bed depth and width, the Manning coefficient and the baseflow concentration time. The calibration process stands in the minimization of a cost function using an evolutionnary, global and multi-objective algorithm that describes the difference between the simulated and the observed WSE. We found that the calibration procedure is able to retrieve an optimal set of parameters such that it brings the simulated WSE closer to the observation. Still with a global calibration procedure where a uniform correction is applied, the improvement is limited to a mean correction over the catchment and the simulation period. We conclude that in order to benefit from the high resolution and complete coverage of the SWOT mission, the calibration process should be achieved sequentially in time over sub-domains as observations become available.

The Amazon Region; A Vision of Sovereignty

DTIC Science & Technology

1998-04-06

and SPOT remote sensing satellites images, about 90% of the Amazon jungle remains almost untouched9. This 280 million hectares of vegetation hold...increasing energy needs, remain unanswered. Indian rights Has the Indian population been jeopardized by the development of the Amazon Region...or government agency. STRATEGY RESEARCH PROJECT THE AMAZON REGION; A VISION OF SOVEREIGNTY BY LIEUTENANT COLONEL EDUARDO JOSE BARBOSA

Fragmentation of Andes-to-Amazon connectivity by hydropower dams

PubMed Central

Anderson, Elizabeth P.; Jenkins, Clinton N.; Heilpern, Sebastian; Maldonado-Ocampo, Javier A.; Carvajal-Vallejos, Fernando M.; Encalada, Andrea C.; Rivadeneira, Juan Francisco; Hidalgo, Max; Cañas, Carlos M.; Ortega, Hernan; Salcedo, Norma; Maldonado, Mabel; Tedesco, Pablo A.

2018-01-01

Andes-to-Amazon river connectivity controls numerous natural and human systems in the greater Amazon. However, it is being rapidly altered by a wave of new hydropower development, the impacts of which have been previously underestimated. We document 142 dams existing or under construction and 160 proposed dams for rivers draining the Andean headwaters of the Amazon. Existing dams have fragmented the tributary networks of six of eight major Andean Amazon river basins. Proposed dams could result in significant losses in river connectivity in river mainstems of five of eight major systems—the Napo, Marañón, Ucayali, Beni, and Mamoré. With a newly reported 671 freshwater fish species inhabiting the Andean headwaters of the Amazon (>500 m), dams threaten previously unrecognized biodiversity, particularly among endemic and migratory species. Because Andean rivers contribute most of the sediment in the mainstem Amazon, losses in river connectivity translate to drastic alteration of river channel and floodplain geomorphology and associated ecosystem services. PMID:29399629

Fragmentation of Andes-to-Amazon connectivity by hydropower dams.

PubMed

Anderson, Elizabeth P; Jenkins, Clinton N; Heilpern, Sebastian; Maldonado-Ocampo, Javier A; Carvajal-Vallejos, Fernando M; Encalada, Andrea C; Rivadeneira, Juan Francisco; Hidalgo, Max; Cañas, Carlos M; Ortega, Hernan; Salcedo, Norma; Maldonado, Mabel; Tedesco, Pablo A

2018-01-01

Andes-to-Amazon river connectivity controls numerous natural and human systems in the greater Amazon. However, it is being rapidly altered by a wave of new hydropower development, the impacts of which have been previously underestimated. We document 142 dams existing or under construction and 160 proposed dams for rivers draining the Andean headwaters of the Amazon. Existing dams have fragmented the tributary networks of six of eight major Andean Amazon river basins. Proposed dams could result in significant losses in river connectivity in river mainstems of five of eight major systems-the Napo, Marañón, Ucayali, Beni, and Mamoré. With a newly reported 671 freshwater fish species inhabiting the Andean headwaters of the Amazon (>500 m), dams threaten previously unrecognized biodiversity, particularly among endemic and migratory species. Because Andean rivers contribute most of the sediment in the mainstem Amazon, losses in river connectivity translate to drastic alteration of river channel and floodplain geomorphology and associated ecosystem services.

Hafnium and neodymium isotopes and REY distribution in the truly dissolved, nanoparticulate/colloidal and suspended loads of rivers in the Amazon Basin, Brazil

NASA Astrophysics Data System (ADS)

Merschel, Gila; Bau, Michael; Schmidt, Katja; Münker, Carsten; Dantas, Elton L.

2017-09-01

Radiogenic isotopes in river sediments and river waters have been widely used in provenance studies, as these samples naturally integrate the geology/chemistry of the entire catchment. While the Hf and Nd isotope systems are coupled during igneous processes, they are decoupled during supergene processes at the Earth's surface, which is reflected by the isotope composition of riverine sediments. We present the first data for both Hf and Nd isotope compositions of the dissolved (0.2 μm-filtrates rich in nanoparticles and colloids, NPCs) and the truly dissolved (1 kDa-ultrafiltrates) load of rivers. Hafnium and Nd isotope compositions and concentrations of the Rare Earths and Yttrium (REY) and Hf were determined for suspended particles (>0.2 μm) as well as for the dissolved and the truly dissolved load of the Rio Solimões, the Amazon's largest tributary draining the Andes, and of the Rio Negro, an organic NPC- and particle-rich river draining the rainforest of northern Amazonia. We also analyzed the Nd isotope compositions of suspended sediments and 0.2 μm-filtered water samples from the Amazon River and its tributaries Rio Tapajos, Rio Xingu and Rio Jari. Our novel results clearly show that the decoupling of the Hf and Nd isotope systems is related to incongruent weathering processes on the continent, as this decoupling can already be observed in the different Hf and Nd pools, i.e. in the particulate, the NPC-dominated dissolved and the truly dissolved load of rivers. In the Rio Negro and Rio Solimões, a strong particle size-dependent difference in Hf isotope composition is observed. Values of εHf become more radiogenic as filter poresize decreases, which can be related to the density- and size-dependent distribution of Hf-rich minerals, e.g. zircons, and their absence from the truly dissolved pool. In contrast, the Nd isotope composition of Amazonian river waters reflects that of their catchment geology. Tributaries draining the Precambrian Brazilian and Guyana shields show very unradiogenic εNd values of -19 to -25 in their dissolved load, whereas the Rio Solimões draining the Andes yields a more radiogenic εNd signal of only -7. The dissolved Nd isotope composition of the Amazon is dominated by its Andean tributaries and averages at -8. Although Nd isotope compositions are thought to not being fractionated by Earth surface processes, significant differences of 1.3-1.9 ε-units can be observed between the dissolved and suspended loads in the Amazon River and its main tributary, the Rio Solimões. In these rivers, the dissolved load is more radiogenic than the suspended sediment, which is likely due to incongruent weathering and related mineral sorting in the Andean headwaters. In contrast, the organic-rich and mineral-poor shield rivers do not show a difference between the truly dissolved, dissolved and suspended load, as the Nd in all these pools is controlled by surface- and solution-complexation and hence isotopically homogenized by continuous exchange and re-equilibration.

A Novel Diffuse Fraction-Based Two-Leaf Light Use Efficiency Model: An Application Quantifying Photosynthetic Seasonality across 20 AmeriFlux Flux Tower Sites

NASA Astrophysics Data System (ADS)

Yan, Hao; Wang, Shao-Qiang; Yu, Kai-Liang; Wang, Bin; Yu, Qin; Bohrer, Gil; Billesbach, Dave; Bracho, Rosvel; Rahman, Faiz; Shugart, Herman H.

2017-10-01

Diffuse radiation can increase canopy light use efficiency (LUE). This creates the need to differentiate the effects of direct and diffuse radiation when simulating terrestrial gross primary production (GPP). Here, we present a novel GPP model, the diffuse-fraction-based two-leaf model (DTEC), which includes the leaf response to direct and diffuse radiation, and treats maximum LUE for shaded leaves (ɛmsh defined as a power function of the diffuse fraction (Df)) and sunlit leaves (ɛmsu defined as a constant) separately. An Amazonian rainforest site (KM67) was used to calibrate the model by simulating the linear relationship between monthly canopy LUE and Df. This showed a positive response of forest GPP to atmospheric diffuse radiation, and suggested that diffuse radiation was more limiting than global radiation and water availability for Amazon rainforest GPP on a monthly scale. Further evaluation at 20 independent AmeriFlux sites showed that the DTEC model, when driven by monthly meteorological data and MODIS leaf area index (LAI) products, explained 70% of the variability observed in monthly flux tower GPP. This exceeded the 51% accounted for by the MODIS 17A2 big-leaf GPP product. The DTEC model's explicit accounting for the impacts of diffuse radiation and soil water stress along with its parameterization for C4 and C3 plants was responsible for this difference. The evaluation of DTEC at Amazon rainforest sites demonstrated its potential to capture the unique seasonality of higher GPP during the diffuse radiation-dominated wet season. Our results highlight the importance of diffuse radiation in seasonal GPP simulation.