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1
Oliveira-da-Costa, Marcelo, Miriam Marmontel, Daiane S. X. da-Rosa, André Coelho, Serge Wich, Federico Mosquera-Guerra, and Fernando Trujillo. "Effectiveness of unmanned aerial vehicles to detect Amazon dolphins." Oryx 54, no. 5 (October 23, 2019): 696–98. http://dx.doi.org/10.1017/s0030605319000279.
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AbstractQuantifying the abundance of species is essential for their management and conservation. Much effort has been invested in surveys of freshwater dolphins in the Amazon basin but river dimensions and complex logistics limit replication of such studies across the region. We evaluated the effectiveness of using unmanned aerial vehicles (UAVs) for surveying two Amazon dolphin species, the tucuxi Sotalia fluviatilis and pink river dolphin Inia geoffrensis, in tropical rivers. In 2016 we conducted drone and visual surveys over 80 km of the Juruá River in Brazil. The aerial surveys provided higher accuracy than human observers in counting individuals detected in groups. Compared to estimates derived from visual surveys, the use of UAVs could provide a more feasible, economical and accurate estimate of Amazon river dolphin populations. The method could potentially be replicated in other important areas for the conservation of these species, to generate an improved index of river dolphin populations in the Amazon.
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Rocha da Silva, Maria do Socorro, Eduardo Antonio Ríos-Villamizar, Hillândia Brandão da Cunha, Sebastião Átila Fonseca Miranda, Sávio José Filgueiras Ferreira, Sergio R. Bulcão Bringel, Núbia Abrantes Gomes, Domitila Pascoaloto, and Luana Monteiro Silva. "A CONTRIBUTION TO THE HYDROCHEMISTRY AND WATER TYPOLOGY OF THE AMAZON RIVER AND ITS TRIBUTARIES." Caminhos de Geografia 20, no. 72 (December 23, 2019): 360–74. http://dx.doi.org/10.14393/rcg207246295.
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The geological diversity of the Amazon Basin, as well as the pluvial regime, influences the characteristics of the waters. To know the water types of the rivers of the Amazon basin, 288 superficial water samples were collected, 94 of them along the Amazon River and 194 in their tributaries, from March 2009 to September 2012. The physical, chemical, and physicochemical properties were analyzed. Rivers with pH between 6.5 and 7.6 and electrical conductivity (40.00 - 80.00 μS cm-1) are water bodies that are influenced by the Andean region (e.g., the Amazon River and some of its right bank tributaries). On the other hand, the rivers with pH in the range of 3.5 to 5.5 and conductivity <30.00 μS cm-1, which are Amazon River’s left bank tributaries, reflect the characteristics of the Guiana Shield. The rivers with pH (6.0 to 7.0), low ionic charge, and conductivity <40.0 μS cm-1, such as the lower Amazon River’s right bank tributaries (Tapajos and Xingu) which are influenced by the Central Brazilian Shield, and also the middle/upper Amazon River’s right bank tributaries (Tefé, Coari and Jutaí).
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KANE, R. P. "Inter-annual variability of rainfalls in the Amazon basin and its vicinity." MAUSAM 58, no. 3 (November 26, 2021): 351–60. http://dx.doi.org/10.54302/mausam.v58i3.1330.
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An analysis of the rainfall series (12-month running means) of the 5° × 5° gridded data in the Amazon river basin and its vicinity (15° N – 20° S, 30° - 80° W) indicated that the rainfalls were highly variable both from year to year and from region to region. Correlations with even nearby regions hardly exceeded 0.50, though correlations were better (up to 0.70) in the regions near the eastern coast of Brazil. Moderate relationship with ENSO indices was obtained for the Amazon river basin and the regions to its north, and for NE Brazil, while moderate relationship with South Atlantic SST was obtained for NE Brazil and the region immediately to its west. All other relationships (with 30 hPa wind, North Atlantic Oscillation Index, etc.) were obscure.
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Nittrouer, Charles A., David J. DeMaster, Steven A. Kuehl, Alberto G. Figueiredo, Richard W. Sternberg, L. Ercilio C. Faria, Odete M. Silveira, et al. "Amazon Sediment Transport and Accumulation Along the Continuum of Mixed Fluvial and Marine Processes." Annual Review of Marine Science 13, no. 1 (January 3, 2021): 501–36. http://dx.doi.org/10.1146/annurev-marine-010816-060457.
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Sediment transfer from land to ocean begins in coastal settings and, for large rivers such as the Amazon, has dramatic impacts over thousands of kilometers covering diverse environmental conditions. In the relatively natural Amazon tidal river, combinations of fluvial and marine processes transition toward the ocean, affecting the transport and accumulation of sediment in floodplains and tributary mouths. The enormous discharge of Amazon fresh water causes estuarine processes to occur on the continental shelf, where much sediment accumulation creates a large clinoform structure and where additional sediment accumulates along its shoreward boundary in tidal flats and mangrove forests. Some remaining Amazon sediment is transported beyond the region near the river mouth, and fluvial forces on it diminish. Numerous perturbations to Amazon sediment transport and accumulation occur naturally, but human actions will likely dominate future change, and now is the time to document, understand, and mitigate their impacts.
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Cohen, Julia Clarinda Paiva, David Roy Fitzjarrald, Flávio Augusto Farias D'Oliveira, Ivan Saraiva, Illelson Rafael da Silva Barbosa, Adilson Wagner Gandu, and Paulo Afonso Kuhn. "Radar-observed spatial and temporal rainfall variability near the Tapajós-Amazon confluence." Revista Brasileira de Meteorologia 29, spe (December 2014): 23–30. http://dx.doi.org/10.1590/0102-778620130058.
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Standard Amazonian rainfall climatologies rely on stations preferentially located near river margins. River breeze circulations that tend to suppress afternoon rainfall near the river and enhance it inland are not typically considered when reporting results. Previous studies found surprising nocturnal rainfall maxima near the rivers in some locations. We examine spatial and temporal rainfall variability in the Santarém region of the Tapajós-Amazon confluence, seeking to describe the importance of breeze effects on afternoon precipitation and defining the areal extent of nocturnal rainfall maxima.We used three years of mean S band radar reflectivity from Santarém airport with a Z-R relationship appropriate for tropical convective conditions. These data were complemented by TRMM satellite rainfall estimates. Nocturnal rainfall was enhanced along the Amazon River, consistent with the hypothesis that these are associated with the passage of instability lines, perhaps enhanced by local channeling and by land breeze convergence. In the daytime, two rainfall bands appear in mean results, along the east bank of the Tapajós River and to the south of the Amazon River, respectively.
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Maslin, Mark A., and Stephen J. Burns. "Reconstruction of the Amazon Basin Effective Moisture Availability over the Past 14,000 Years." Science 290, no. 5500 (December 22, 2000): 2285–87. http://dx.doi.org/10.1126/science.290.5500.2285.
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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.
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L., Maria Doris Escobar, Izeni P. Farias, Donald C. Taphorn B., Miguel Landines, and Tomas Hrbek. "Molecular diagnosis of the arowanas Osteoglossum ferreirai Kanazawa, 1966 and O. bicirrhossum (Cuvier, 1829) from the Orinoco and Amazon River basins." Neotropical Ichthyology 11, no. 2 (June 2013): 335–40. http://dx.doi.org/10.1590/s1679-62252013000200011.
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The arowanas, fishes of Gondwanan origin, are represented in South America by the genus Osteoglossum. All species were initially reported as being exclusive to the Amazon region, with O. ferreirai restricted to the Negro River basin and O. bicirrhosum to the Amazon and Essequibo Rivers basin. Starting in the mid 1970's it was reported that O. ferreirai also occurs in the Orinoco River basin. In all regions the arowanas assumed significant socio-economic importance due to their popularity in the international ornamental fish trade, leading to over-exploitation of both species in some areas. The Orinoco populations are particularly heavily exploited, and thus conservation and management measures are needed. Both depend on the clarification of taxonomic status, and phylogenetic distinctness of the Orinoco populations. With the goal of molecularly characterizing the two species of Osteoglossum, and comparing populations of Osteoglossum from the Orinoco and Amazon basins, we characterized individuals sampled from eight localities, one in the Orinoco River basin and seven in the Amazon River basin. We sampled 39 individuals, obtaining 1004 base pairs, of which 79 were synapomorphies. Genetic distance between the two species calculated using the HKY + G model of molecular evolution was 8.94%. Intraspecific distances ranged from 0.42% in O. bicirrhosum to 0.10% in O. ferreirai. The genetic characterization confirmed the taxonomic status of O. ferreirai in the Orinoco basin, and suggested that its distribution in the Orinoco basin is unlikely to be the result of vicariance or natural dispersal, but rather an anthropic introduction.
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Yu, Di, Shidong Liu, Guangxue Li, Yi Zhong, Jun Liang, Jinghao Shi, Xue Liu, and Xiangdong Wang. "The River–Sea Interaction off the Amazon Estuary." Remote Sensing 14, no. 4 (February 20, 2022): 1022. http://dx.doi.org/10.3390/rs14041022.
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The Amazon River has the highest discharge in the world. Nevertheless, there is still a lack of the research on the interaction between river-diluted water and the ocean. This study used the remote sensing data (2008–2017) of the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite, and data of the currents, wind fields, sea surface temperature, and water depth. The river–sea interaction off the Amazon estuary was studied by analyzing the diffusion of river-diluted water and the distribution of surface suspended particulate matter (SPM). The results revealed that the Amazon estuary has a “filter effect,” whereby the distribution of the surface SPM exhibited significant spatial characteristics of being high in the nearshore area and low in the offshore area. Most of the SPM accumulated within the estuary in a fan shape, although some was distributed in the shallow water region of the continental shelf along the coasts on both sides of the estuary. The currents were found to limit the diffusion range of SPM. The flow direction and velocity of the North Brazil Current and the North Equatorial Countercurrent, which are largely driven by the magnitude of the trade wind stress, are the main forces controlling the long-distance diffusion of diluted water, thus forming unique river–sea interaction patterns in the Amazon estuary. This research provides a supplement and reference for the study of the diffusion process of SPM and river-diluted water, and on the estuarine river–sea interactions of other large rivers worldwide.
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Pereira, Fabiana da Silva, and Ima Célia Guimarães Vieira. "Anthropic transformation in the Gurupi river basin, eastern Amazon." Sustentabilidade em Debate 10, no. 3 (December 31, 2019): 212–35. http://dx.doi.org/10.18472/sustdeb.v10n3.2019.23799.
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The objective of this paper was to evaluate the degree of anthropic transformation of a river basin in the Amazon region. We used the digital data of the TerraClass Project to calculate the Anthropic Transformation Index - ATI. In order to verify spatial and temporal changes along a decade in the Gurupi river basin, we used the database of the years 2004 and 2014. The results showed an increase of anthropic changes in the basin over a decade, as a result of forest cover conversion into agricultural and pastures areas. Although the Gurupi river basin remains at a regular level of degradation after a decade, the intensification of land use and land cover change is a threat to the few rainforest remnants of the river basin, which can lead the region to the next level of degradation, if effective forest protection, conservation and restoration actions are not implemented in the region.
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de Sousa, Rodrigo Silva, Gilmar Clemente Silva, Thiago Bazzan, Fernando de la Torre, Caroline Nebo, Diógenes Henrique Siqueira-Silva, Sheila Cardoso-Silva, et al. "Connections among Land Use, Water Quality, Biodiversity of Aquatic Invertebrates, and Fish Behavior in Amazon Rivers." Toxics 10, no. 4 (April 7, 2022): 182. http://dx.doi.org/10.3390/toxics10040182.
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Rivers in the Amazon have among the greatest biodiversity in the world. The Xingu River, one of the tributaries of the Amazon River, has a length of 1640 km, draining 510,000 km2 in one of the most protected regions on the planet. The Middle Xingu region in Brazil has been highly impacted by mining and livestock farming, leading to habitat fragmentation due to altered water quality. Therefore, comparing two rivers (the preserved Xingu River and the impacted Fresco River) and their confluence, the aims of the present study were to (1) assess the land uses in the hydrographic basin; (2) determine the water quality by measurements of turbidity, total solids, and metals (Cd, Cu, Fe, Mn, Pb, Zn, and Hg); (3) compare the zooplankton biodiversity; and (4) to evaluate the avoidance behavior of fish (Astyanax bimaculatus) when exposed to waters from the Xingu and Fresco Rivers. Zooplankton were grouped and counted down to the family level. For the analysis of fish avoidance, a multi-compartment system was used. The forest class predominated at the study locations, accounting for 57.6%, 60.8%, and 63.9% of the total area at P1XR, P2FR, and P3XFR, respectively, although since 1985, at the same points, the forest had been reduced by 31.3%, 25.7%, and 27.9%. The Xingu River presented almost 300% more invertebrate families than the Fresco River, and the fish population preferred its waters (>50%). The inputs from the Fresco River impacted the water quality of the Xingu River, leading to reductions in local invertebrate biodiversity and potential habitats for fish in a typical case of habitat fragmentation due to anthropic factors.
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Valerio, Aline de M., Milton Kampel, Vincent Vantrepotte, Nicholas D. Ward, and Jeffrey E. Richey. "Optical Classification of Lower Amazon Waters Based on In Situ Data and Sentinel-3 Ocean and Land Color Instrument Imagery." Remote Sensing 13, no. 16 (August 4, 2021): 3057. http://dx.doi.org/10.3390/rs13163057.
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Optical water types (OWTs) were identified from an in situ dataset of concomitant biogeochemical and optical parameters acquired in the Amazon River and its tributaries, in the Lower Amazon region, at different hydrological conditions from 2014 to 2017. A seasonal bio-optical characterization was performed. The k-means classification was applied to the in situ normalized reflectance spectra (rn(λ)), allowing the identification of four OWTs. An optical index method was also applied to the rn(λ) defining the thresholds of the OWTs. Next, level-3 Sentinel-3 Ocean and Land Color Instrument images representative of the seasonal discharge conditions were classified using the identified in situ OWTs as reference. The differences between Amazon River and clearwater tributary OWTs were dependent on the hydrological dynamics of the Amazon River, also showing a strong seasonal variability. Each OWT was associated with a specific bio-optical and biogeochemical environment assessed from the corresponding absorption coefficient values of colored dissolved organic matter (aCDOM) and particulate matter (ap), chlorophyll-a and suspended particulate matter (SPM) concentrations, and aCDOM/ap ratio. The rising water season presented a unique OWT with high SPM concentration and high relative contribution of ap to total absorption compared to the other OWTs. This bio-optical characterization of Lower Amazon River waters represents a first step for developing remote sensing inversion models adjusted to the optical complexity of this region.
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Godoy, Fernando Igor de, Edson Guilherme, Diego Pedroza, and Ricardo Antônio de Andrade Plácido. "Avifauna of the upper Purus River: relevant records for an area lacking ornithological surveys." Papéis Avulsos de Zoologia 61 (February 18, 2021): e20216121. http://dx.doi.org/10.11606/1807-0205/2021.61.21.
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Birds are the best-known vertebrate group, although many localities in the world are considered to be knowledge gaps. This is the case of many little-known environments in the Amazon biome, the world’s largest tropical forest. Here, we present a survey of birds in the upper Purus basin, comprising the municipalities of Manoel Urbano and Feijó in the Brazilian state of Acre, and Boca do Acre and Pauini in the state of Amazonas. In this region, poorly-studied habitats, such as open rainforest dominated by palms or bamboo, still predominate. We recorded 452 bird species during 45 field trips between May and July in 2016, and June to August in 2017. Twenty-four of these species are associated with bamboo habitat, 28 are endemic to the southwestern Amazon basin, and seven are threatened with extinction. This high diversity is typical of the western Amazon basin, one of the richest regions in the world in the number of species, due to the heterogeneity of the local environments. The data presented here highlight the importance of the region for the conservation of birds, including species typical of the western Amazon, some of which are still poorly-known.
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Shibuya, Akemi, and Jansen Zuanon. "Catfishes as prey items of Potamotrygonid stingrays in the Solimões and Negro rivers, Brazilian Amazon." Biota Neotropica 13, no. 1 (March 2013): 376–79. http://dx.doi.org/10.1590/s1676-06032013000100041.
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In spite of the fact that catfish have rarely been reported as food items in the diets of freshwater stingrays, they are commonly observed in the stomach contents of species inhabiting the Solimões and Negro rivers in the Brazilian Amazon. The stomach contents of six rays from the Solimões River and 64 from the Negro River were analyzed, and catfishes (distributed among the families Callichthyidae, Cetopsidae, Doradidae and Loricariidae) were found in the stomach contents of four and 10 of these rays, respectively, comprising a frequency of occurrence of 20%. These data indicate a relevant participation of catfishes in the diets of potamotrygonid rays in the Amazon, and may reflect the regional diversity and abundance of Siluriformes in the region.
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Pereira, Luci Cajueiro Carneiro, Natália do Socorro da Silva Sousa, Brenda Ribeiro Padilha da Silva, Ana Lucia Biondo da Costa, Francielle Raquel Baltazar Cavalcante, Laiane Maria dos Santos Rodrigues, and Rauquírio Marinho da Costa. "Influence of Anthropogenic Activities on the Water Quality of an Urban River in an Unplanned Zone of the Amazonian Coast." Limnological Review 23, no. 2 (September 6, 2023): 108–25. http://dx.doi.org/10.3390/limnolrev23020007.
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The database on water quality in Amazonian rivers located in unplanned urbanized regions along the Brazilian Amazon Coast is still quite limited. This study addresses these concerns, and the tested hypothesis was that the water quality of the Cereja River has deteriorated in recent years, despite the efforts of government authorities to mitigate anthropogenic impacts. To assess changes in water quality, seven campaigns were conducted, collecting data at six fixed points during two different periods. High-resolution satellite images were used to document unplanned occupation. Unfortunately, the number of houses along the Cereja River has increased, in violation of the law. This has contributed to the river’s intense trophic condition, lower dissolved oxygen concentrations, higher concentrations of pathogenic bacteria, and loss of vegetation cover. According to national water quality standards, the Cereja is unsuitable for any human use. This is in stark contrast to the scenario a few decades ago when the river was used for leisure, fishing, and other activities. The results obtained confirm the initial hypothesis and can support potential management strategies and decision-making by authorities. The observed scenario can be extrapolated to other rivers located in urban areas in the Amazon region that have similarly regrettably experienced relatively uncontrolled growth.
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Ffield, Amy. "Amazon and Orinoco River Plumes and NBC Rings: Bystanders or Participants in Hurricane Events?" Journal of Climate 20, no. 2 (January 15, 2007): 316–33. http://dx.doi.org/10.1175/jcli3985.1.
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Abstract The Amazon and Orinoco River plumes and North Brazil Current (NBC) rings are investigated during the 1 June through 30 November Atlantic hurricane season to identify their impact on upper-ocean temperatures in the region and to draw attention to their potential role in hurricane maintenance and intensification. The analysis uses ocean temperature and salinity stratification data, infrared and microwave satellite-derived sea surface temperature (SST) data, and Atlantic tropical storm and hurricane tracks data. The Amazon–Orinoco River plume spreads into the western equatorial Atlantic Ocean forming an extensive (0°–20°N, 78°–33°W) 10–60-m-thick buoyant surface layer associated with the warmest surface temperatures (up to +3°C) in the region due to the freshwater barrier layer effect. At times the warm Amazon–Orinoco River plume is bisected by cool-surface NBC rings. For the 1960 to 2000 time period, 68% of all category 5 hurricanes passed directly over the historical region of the plume, revealing that most of the most destructive hurricanes may be influenced by ocean–atmosphere interaction with the warm plume just prior to reaching the Caribbean. Statistical analyses of tropical Atlantic SSTs and tropical cyclone wind speeds reveal a significant and unique relationship between warm (cool) SSTs in the Amazon–Orinoco River plume and stronger (weaker) tropical cyclone wind speeds between 35° and 55°W. This implies that warmer (cooler) plume SSTs due to increased (decreased) river discharge may directly contribute to a more (less) vigorous hurricane season.
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DE OLIVEIRA, ELANE D. CUNHA, ALAN C. DA CUNHA, NATALINA B. DA SILVA, RAQUEL CASTELO-BRANCO, JOÃO MORAIS, MARIA PAULA C. SCHNEIDER, SILVIA M. M. FAUSTINO, VITOR RAMOS, and VITOR VASCONCELOS. "Morphological and molecular characterization of cyanobacterial isolates from the mouth of the Amazon River." Phytotaxa 387, no. 4 (January 11, 2019): 269. http://dx.doi.org/10.11646/phytotaxa.387.4.1.
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The Amazon region contains a great diversity of species, and the Amazon River basin accounts for almost 20% of all the freshwater in the world. Despite the favorable environmental conditions in this region, little is known about the cyanobacterial diversity of this waterbody, especially at the mouth of the river. In this paper, we used the polyphasic approach to identify 14 cyanobacterial strains isolated in the Amazon River on the inlet site from a drinking water supply located close to the river mouth. The isolated strains were characterized based on morphology, behavior in culture, 16S rRNA gene sequencing, phylogenetic analysis and potential for toxin production. The isolated strains belong to seven different genera, namely, Alkalinema, Cephalothrix, Limnothrix, Leptolyngbya, Phormidium, Pseudanabaena and an unidentified Nostocales taxa that may represent a new genus. Strikingly, there were no new species, nor detection of gene clusters associated with cyanotoxin production. However, the phylogenetic placements of the Amazonian strains of Limnothrix and Pseudanabaena provide new insight into the taxonomy of these genera, reinforcing the need for taxonomic revision.
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Barcelos Neto, Aristóteles. "Festas para um nobre: ritual e (re)producao sociopolítica no Alto Xingu." Estudios Latinoamericanos 23 (December 31, 2003): 63–90. http://dx.doi.org/10.36447/estudios2003.v23.art4.
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Carvalho, Tiago P., Julio Araújo Flores, Jessica Espino, Giannina Trevejo, Hernan Ortega, Fernando C. Jerep, Roberto E. Reis, and James S. Albert. "Fishes from the Las Piedras River, Madre de Dios basin, Peruvian Amazon." Check List 8, no. 5 (September 1, 2012): 973. http://dx.doi.org/10.15560/8.5.973.
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We report results of an ichthyological survey on the Las Piedras basin, a tributary of the Madre de Dios River located in the southwestern portion of the Amazon Basin in southeastern Peru. Collections were made at low water (June, 2011) from 180 - 270 m elevation, within the Fitzcarrald Arch. This is the last of four expeditions to the region with the goal of comparing the ichthyofaunas across the headwaters of the largest tributary basins in the western Amazon: Juruá, Ucayali, Purús and Madre de Dios rivers. Twenty-one sites along the Las Piedras River and its tributaries were sampled and a total of 144 species belonging to 32 families and seven orders were captured and identified. The most diverse families were Characidae (34 spp.), Loricariidae (23 spp.), and Pimelodidae (19 spp.).
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Carmo, Lucas, Alline Mota, and Cecilia Manoel. "Hemopneumothorax Caused By River Stingray Accident In The Amazon Region." Residência Pediátrica 8, no. 1 (April 2018): 51–54. http://dx.doi.org/10.25060/residpediatr-2018.v8n1-09.
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FAVACHO, Breno Inglis, Jerson Rogério Pinheiro VAZ, André Luiz Amarante MESQUITA, Fábio LOPES, Antonio Luciano Seabra MOREIRA, Newton Sure SOEIRO, and Otávio Fernandes Lima da ROCHA. "Contribution to the marine propeller hydrodynamic design for small boats in the Amazon region." Acta Amazonica 46, no. 1 (March 2016): 37–46. http://dx.doi.org/10.1590/1809-4392201501723.
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ABSTRACTIn the Amazon, river navigation is very important due to the length of navigable rivers and the lack of alternative road networks. Boats usually operate in unfavorable conditions, since there is no hydrodynamic relation among propellers, geometry, and the dimensions of the boat hull. Currently, there is no methodology for propeller hydrodynamic optimization with low computational cost and easy implementation in the region. The aim of this work was to develop a mathematical approach for marine propeller design applied to boats typically found on Amazon rivers. We developed an optimized formulation for the chord and pitch angle distributions, taking into account the classical model of Glauert. A theoretical analysis for the thrust and torque relationships on an annular control volume was performed. The mathematical model used was based on the Blade Element Momentum Theory (BEMT). We concluded that the new methodology proposed in this work demonstrates a good physical behavior when compared with the theory of Glauert and the experimental data of the Wageningen B3-50 propeller.
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da Silva, Luciano Vieira Dias, Simone de Fátima Pinheiro Pereira, Cristiane Costa Carneiro, Thiago De Melo e Silva, Ronaldo Magno Rocha, Hemilton Cardoso Da Costa, Alan Marcel Fernandes De Souza, Pedro Moreira De Souza Junior, Cleber Silva e Silva, and Davis Castro Dos Santos. "Spatial distribution of hg and as in rivers of the eastern amazon impacted by gold mining." Cuadernos de Educación y Desarrollo 15, no. 2 (May 31, 2023): 1807–30. http://dx.doi.org/10.55905/cuadv15n2-039.
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Human activities contribute to the contamination of rivers by toxic elements, causing serious effects on the health of traditional communities in the Amazon region. With the aim of verifying the spatial distribution of Hg and As concentrations in a region affected by gold mining in the Baú, Curuá, and Curuaés River basin, in the municipality of Altamira-PA, in the Brazilian Amazon, a study was carried out using geostatistical maps. The quantification of elements was performed using Inductively Coupled Plasma Emission Spectrometry with hydride generation (HGICP-OES). The obtained values were exported for use in computational processes with the QGIS and Surfer software, in order to produce isotheor maps. The results of the maps showed Hg concentrations that exceeded the limit established by the National Council for the Environment, which is 0.2 µg L-1. This indicates that the presence of mining in the region represents a threat to the ecosystem of these rivers. On the other hand, the maps for As showed that no station presented results that exceeded concentrations above the limit allowed for this element, which is 10 µg L-1. Based on these results, the geostatistical maps were effective in monitoring areas affected by toxic elements and can be used as a tool in the control of river water quality.
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Paiva, R. C. D., W. Collischonn, M. P. Bonnet, and L. G. G. de Gonçalves. "On the sources of hydrological prediction uncertainty in the Amazon." Hydrology and Earth System Sciences 16, no. 9 (September 5, 2012): 3127–37. http://dx.doi.org/10.5194/hess-16-3127-2012.
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Abstract. Recent extreme events in the Amazon River basin and the vulnerability of local population motivate the development of hydrological forecast systems using process based models for this region. In this direction, the knowledge of the source of errors in hydrological forecast systems may guide the choice on improving model structure, model forcings or developing data assimilation systems for estimation of initial model states. We evaluate the relative importance of hydrologic initial conditions and model meteorological forcings errors (precipitation) as sources of stream flow forecast uncertainty in the Amazon River basin. We used a hindcast approach that compares Ensemble Streamflow Prediction (ESP) and a reverse Ensemble Streamflow Prediction (reverse-ESP). Simulations were performed using the physically-based and distributed hydrological model MGB-IPH, comprising surface energy and water balance, soil water, river and floodplain hydrodynamics processes. The model was forced using TRMM 3B42 precipitation estimates. Results show that uncertainty on initial conditions plays an important role for discharge predictability, even for large lead times (∼1 to 3 months) on main Amazonian Rivers. Initial conditions of surface waters state variables are the major source of hydrological forecast uncertainty, mainly in rivers with low slope and large floodplains. Initial conditions of groundwater state variables are important, mostly during low flow period and in the southeast part of the Amazon where lithology and the strong rainfall seasonality with a marked dry season may be the explaining factors. Analyses indicate that hydrological forecasts based on a hydrological model forced with historical meteorological data and optimal initial conditions may be feasible. Also, development of data assimilation methods is encouraged for this region.
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Paiva, R. C. D., W. Collischonn, M. P. Bonnet, and L. G. G. Gonçalves. "On the sources of hydrological prediction uncertainty in the Amazon." Hydrology and Earth System Sciences Discussions 9, no. 3 (March 20, 2012): 3739–60. http://dx.doi.org/10.5194/hessd-9-3739-2012.
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Abstract. Recent extreme events in the Amazon River basin and the vulnerability of local population motivate the development of hydrological forecast systems (HFSs) using process based models for this region. In this direction, the knowledge of the source of errors in HFSs may guide the choice on improving model structure, model forcings or developing data assimilation (DA) systems for estimation of initial model states. We evaluate the relative importance of hydrologic initial conditions (ICs) and model meteorological forcings (MFs) errors (precisely precipitation) as sources of stream flow forecast uncertainty in the Amazon River basin. We used a hindcast approach developed by Wood and Lettenmaier (2008) that contrasts Ensemble Streamflow Prediction (ESP) and a reverse Ensemble Streamflow Prediction (reverse-ESP). Simulations were performed using the physically-based and distributed hydrological model MGB-IPH, comprising surface energy and water balance, soil water, river and floodplain hydrodynamics processes. Model was forced using TRMM 3B42 precipitation estimates. Results show that uncertainty on initial conditions play an important role for discharge predictability even for large lead times (~1 to 3 months) on main Amazonian Rivers. ICs of surface waters state variables are the major source of hydrological forecast uncertainty, mainly in rivers with low slope and large floodplains. ICs of groundwater state variables are important mostly during low flow period and southeast part of the Amazon, where lithology and the strong rainfall seasonality with a marked dry season may be the explaining factors. Analyses indicate that hydrological forecasts based on a hydrological model forced with historical meteorological data and optimal initial conditions, may be feasible. Also, development of DA methods is encouraged for this region.
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Aliaga-Rossel, E., T. L. McGuire, and H. Hamilton. "Distribution and encounter rates of the river dolphin (Inia geoffrensis boliviensis) in the central Bolivian Amazon." J. Cetacean Res. Manage. 8, no. 1 (March 8, 2023): 87–92. http://dx.doi.org/10.47536/jcrm.v8i1.705.
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The ecology and conservation status of river dolphins (Inia sp.) distributed in the lowland rivers of Bolivia are poorly understood and only recently have basic studies been conducted to investigate their population size, taxonomic status, distribution, behaviour, environmental threats and ecology in this region. This paper examines the distribution and encounter rates of the bufeo (Inia sp.) in the middle reach of the Bolivian Amazon and was conducted in the Mamoré River and four of its tributaries during the low water season. Methods were employed which can be replicated during future surveys of Bolivian river dolphins and the results can be compared with those from surveys of Inia throughout its range. Sixty-two hours were spent surveying for dolphins, with 68% of the effort in Mamoré River and 32% in its tributaries. The Inia encounter rates reported here (1.6-5.8 dolphins km21) are the highest recorded anywhere in its broad geographic range; and indicate the importance of continuing and expanding surveys in this area. The mean group size was greatest in the Tijamuchi River (3.3±2.96) and smallest in the Yacuma River (1.8±0.75) and the maximum group size was 14. The high bufeo encounter rates in the central Bolivian Amazon can be taken as a reflection of the general environmental status of the region; however, a growing human population, associated with an increase in boat traffic and fishing activity, poses a future threat to bufeos and their aquatic habitats.
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Santos, Geraldo Mendes dos. "Alfred Wallace's Echoes in the Amazon." World Journal of Social Science 6, no. 1 (January 22, 2019): 15. http://dx.doi.org/10.5430/wjss.v6n1p15.
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This article deals with some aspects of Alfred Russel Wallace's historic journey to the Amazon between 1848 and1852. In it are highlighted the impressions that this naturalist has pointed out about the region, cities, indigenouscustoms and especially about fish of the Black River. More objectively, the article discusses the reasons for the trip,the two trips to the Uaupés River, and the strategic visions Wallace presented about food production in that distantregion. At the end is outlined a profile of the personality of this famous traveler and the lessons he left to posterity,especially to the young naturalists and scientists.
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de Linage, C., J. S. Famiglietti, and J. T. Randerson. "Forecasting terrestrial water storage changes in the Amazon Basin using Atlantic and Pacific sea surface temperatures." Hydrology and Earth System Sciences Discussions 10, no. 10 (October 15, 2013): 12453–83. http://dx.doi.org/10.5194/hessd-10-12453-2013.
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Abstract. Floods and droughts frequently affect the Amazon River basin, impacting transportation, river navigation, agriculture, and ecosystem processes within several South American countries. Here we examined how sea surface temperatures (SSTs) influence interannual variability of terrestrial water storage anomalies (TWSAs) in different regions within the Amazon basin and propose a modeling framework for inter-seasonal flood and drought forecasting. Three simple statistical models forced by a linear combination of lagged spatial averages of central Pacific (Niño 4 index) and tropical North Atlantic (TNAI index) SSTs were calibrated against a decade-long record of 3°, monthly TWSAs observed by the Gravity Recovery And Climate Experiment (GRACE) satellite mission. Niño 4 was the primary external forcing in the northeastern region of the Amazon basin whereas TNAI was dominant in central and western regions. A combined model using the two indices improved the fit significantly (p < 0.05) for at least 64% of the grid cells within the basin, compared to models forced solely with Niño 4 or TNAI. The combined model explained 66% of the observed variance in the northeastern region, 39% in the central and western regions, and 43% for the Amazon basin as a whole with a 3 month lead time between the SST indices and TWSAs. Model performance varied seasonally: it was higher than average during the rainfall wet season in the northeastern Amazon and during the dry season in the central and western regions. The predictive capability of the combined model was degraded with increasing lead times. Degradation was smaller in the northeastern Amazon (where 49% of the variance was explained using an 8 month lead time vs. 69% for a 1 month lead time) compared to the central and western Amazon (where 22% of the variance was explained at 8 months vs. 43% at 1 month). These relationships may enable the development of an early warning system for flood and drought risk. This work also strengthens our understanding of the mechanisms regulating interannual variability in Amazon fires, as water storage deficits may subsequently lead to decreases in transpiration and atmospheric water vapor that cause more severe fire weather.
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BUENO FRANCISCO, ALYSSON. "ESTIMATE OF EROSION IN BASIN OF BOARD INDIGENOUS LAND IN BRAZILIAN AMAZON." William Morris Davis - Revista de Geomorfologia 5, no. 2 (April 11, 2024): 1–8. http://dx.doi.org/10.48025/issn2675-6900.v5n2.2024.620.
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The region of the Arinos River, a tributary of the Tapajós River in the Brazilian Amazon, has had areas of deforestation since the 1970s, with activities without rational use of soil. The deep and sandy soils of the Amazon region become susceptible to erosion due to the action of compaction of the cattle herd implanted after deforestation. The water erosion has serious impacts on the equatorial climate region, with erosivity in the order of 14,000 MJ.mm/h/ha/year. The objective of the research was to estimate the rate of erosion in a basin with 1 million hectares, located in an area of deforestation in the Amazon Forest. A geographic database was developed in a geographic information system to map land cover areas, slopes and soil types. From the application of the Universal Equation of Soil Losses, the indices of the factors related to the areas contained in the watershed were used. The result was an estimate of approximately 150,000 tons/hectare/year, with the production of 24 million tons of sediments.
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Giffard, Pierrick, William Llovel, Julien Jouanno, Guillaume Morvan, and Bertrand Decharme. "Contribution of the Amazon River Discharge to Regional Sea Level in the Tropical Atlantic Ocean." Water 11, no. 11 (November 8, 2019): 2348. http://dx.doi.org/10.3390/w11112348.
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The Amazon River is by far the largest river by volume of water in the world, representing around 17% of the global riverine discharge to the oceans. Recent studies suggested that its impact on sea level is potentially important at global and regional scales. This study uses a set of regional simulations based on the ocean model NEMO to quantify the influence of the Amazon runoff on sea level in the Tropical Atlantic Ocean. The model is forced at its boundaries with daily fields from the ocean reanalysis GLORYS2V4. Air-sea fluxes are computed using atmospheric variables from DFS5.2, which is a bias-corrected version of ERAinterim reanalysis. The particularity of this study is that interannual daily runoffs from the up-to-date ISBA-CTRIP land surface model are used. Firstly, mean state of sea level is investigated through a comparison between a simulation with an interannual river discharge and a simulation without any Amazon runoff. Then, the impact of the Amazon River on seasonal and interannual variability of sea level is examined. It was shown that the Amazon River has a local contribution to the mean state sea level at the river mouth but also a remote contribution of 3.3 cm around the whole Caribbean Archipelago, a region threatened by the actual sea level rise. This effect is mostly due to a halosteric sea level contribution for the upper 250 m of the ocean. This occurs in response to the large scale advection of the plume and the downward mixing of subsurface waters at winter time. The Amazon discharge also induces an indirect thermosteric sea level contribution. However, this contribution is of second order and tends to counterbalance the halosteric sea level contribution. Regional mass redistributions are also observed and consist in a 8 cm decrease of the sea level at the river mouth and a 4.5 increases on continental shelves of the Gulf of Mexico and Caribbean Sea. In terms of variability, simulations indicate that the Amazon discharge may contributes to 23% and 12% of the seasonal and interannual sea level variances in the Caribbean Archipelago area. These variances are first explained by the Amazon time mean discharge and show very weak sensitivity to the seasonal and interannual variability of the Amazon runoff.
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Carvalho, Fernando R., Lilian Casatti, Angelo R. Manzotti, and Délcero C. W. Ravazzi. "First record of Arapaima gigas (Schinz, 1822) (Teleostei: Osteoglossomorpha), the “pirarucu”, in the upper Paraná River basin, Southeast Brazil." Check List 11, no. 5 (September 9, 2015): 1729. http://dx.doi.org/10.15560/11.5.1729.
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Arapaima gigas (Schinz), the “pirarucu”, is one of largest freshwater fish of the Neotropical region, naturally occurring in the Amazon, Essequibo, and Orinoco river basins. Herein, it is first recorded from the Grande River, in the upper Paraná River basin. This record is based on the finding of one dead specimen on the left margin of the Grande River, and in situ observation of juveniles and adults in the river.
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Marengo, José A., Carlos A. Nobre, Javier Tomasella, Marcos D. Oyama, Gilvan Sampaio de Oliveira, Rafael de Oliveira, Helio Camargo, Lincoln M. Alves, and I. Foster Brown. "The Drought of Amazonia in 2005." Journal of Climate 21, no. 3 (February 1, 2008): 495–516. http://dx.doi.org/10.1175/2007jcli1600.1.
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Abstract In 2005, large sections of southwestern Amazonia experienced one of the most intense droughts of the last hundred years. The drought severely affected human population along the main channel of the Amazon River and its western and southwestern tributaries, the Solimões (also known as the Amazon River in the other Amazon countries) and the Madeira Rivers, respectively. The river levels fell to historic low levels and navigation along these rivers had to be suspended. The drought did not affect central or eastern Amazonia, a pattern different from the El Niño–related droughts in 1926, 1983, and 1998. The choice of rainfall data used influenced the detection of the drought. While most datasets (station or gridded data) showed negative departures from mean rainfall, one dataset exhibited above-normal rainfall in western Amazonia. The causes of the drought were not related to El Niño but to (i) the anomalously warm tropical North Atlantic, (ii) the reduced intensity in northeast trade wind moisture transport into southern Amazonia during the peak summertime season, and (iii) the weakened upward motion over this section of Amazonia, resulting in reduced convective development and rainfall. The drought conditions were intensified during the dry season into September 2005 when humidity was lower than normal and air temperatures were 3°–5°C warmer than normal. Because of the extended dry season in the region, forest fires affected part of southwestern Amazonia. Rains returned in October 2005 and generated flooding after February 2006.
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Medeiros de Abreu, Carlos Henrique, Elizandra Perez Araújo, Helenilza Ferreira Albuquerque Cunha, Marcelo Teixeira, and Alan Cavalcanti da Cunha. "Domestic sewage dispersion scenarios as a subsidy to the design of urban sewage systems in the Lower Amazon River, Amapá, Brazil." PeerJ 12 (February 27, 2024): e16933. http://dx.doi.org/10.7717/peerj.16933.
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The final in natura discharge of urban domestic sewage in rivers in the Amazon is a widespread practice. In addition, there is an evident lack of knowledge about the self-depurative characteristics of the receiving water bodies in these rivers. This problem is a challenge for designing sanitary sewage system (SSS) projects in the region. We aimed to numerically simulate hydrodynamic scenarios to study pollutant dispersion processes in an urban stretch impacted by domestic sewage in the Lower Amazon River (Amapá, Brazil) using a hydrodynamic model calibrated and coupled to a dispersive model (Lagrangian) (SisBaHiA). The following methodological steps were performed: (a) bathymetric and liquid discharge experimental campaigns using acoustic techniques (acoustic doppler current profiler—ADCP); (b) identification of point and diffuse sources of pollution in the Santana Channel (CSA) and North Channel of the Amazon River (NCM) in Macapá; (c) calibration of the hydrodynamic model and simulation of the dispersive process of domestic sewage plumes; (d) simulation of dispersive process scenarios in two seasonal hydrological periods and different tidal phases. The results of the simulations indicated significant spatiotemporal variations in the plumes, suggesting critical restriction of water quality in the dry period. The hotspot water collection supply station for ETA-CAESA was found to be the most threatened site by diffuse and point source loads. The simulated impacts showed that concentration variation worsens seasonally, restricting the multiple uses of water in both seasonal periods, regardless of tide phase. The pollutant plumes near the coastal-urban zone were apparently more inhibited by the influence of currents, and, due to the greater dilution capacity in the center of the channel, by the effect reversing with the approximation to the riverbank. The research hypotheses were supported: (a) the process of self-depuration of pollutants in the NCM has considerable limitations in shallow areas, and (b) SSS design projects in the region of the Amazon estuarine complex require hydrodynamic and strict water quality assessment, especially when their hydrological-seasonal and bathymetric characteristics are significantly unfavorable to dispersive processes. Thus, a hydrodynamic analysis should be the primary criterion in designing any SSS projects in this stretch of the estuarine Amazon region.
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Diodato, Nazzareno, Naziano Filizola, Pasquale Borrelli, Panos Panagos, and Gianni Bellocchi. "The Rise of Climate-Driven Sediment Discharge in the Amazonian River Basin." Atmosphere 11, no. 2 (February 18, 2020): 208. http://dx.doi.org/10.3390/atmos11020208.
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The occurrence of hydrological extremes in the Amazon region and the associated sediment loss during rainfall events are key features in the global climate system. Climate extremes alter the sediment and carbon balance but the ecological consequences of such changes are poorly understood in this region. With the aim of examining the interactions between precipitation and landscape-scale controls of sediment export from the Amazon basin, we developed a parsimonious hydro-climatological model on a multi-year series (1997–2014) of sediment discharge data taken at the outlet of Óbidos (Brazil) watershed (the narrowest and swiftest part of the Amazon River). The calibrated model (correlation coefficient equal to 0.84) captured the sediment load variability of an independent dataset from a different watershed (the Magdalena River basin), and performed better than three alternative approaches. Our model captured the interdecadal variability and the long-term patterns of sediment export. In our reconstruction of yearly sediment discharge over 1859–2014, we observed that landscape erosion changes are mostly induced by single storm events, and result from coupled effects of droughts and storms over long time scales. By quantifying temporal variations in the sediment produced by weathering, this analysis enables a new understanding of the linkage between climate forcing and river response, which drives sediment dynamics in the Amazon basin.
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Rosa Batista, Gabriela, and Carlos Eduardo Aguiar de Souza Costa. "Influence of climatic phenomena on rainfall in the Tapajós River Basin." Revista Agrogeoambiental 16, unico (May 10, 2024): e20241847. http://dx.doi.org/10.18406/2316-1817v16nunico20241847.
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Climate change results in weather phenomena such as those that are currently being observed, affecting precipitation, possibly more intensely in the Amazon region. This research is justified by the scarcity of climate risk mitigation measures in the Amazon. Rainfall data from 1992 to 2021 were analyzed, revealing long occurrences of dipole anomalies for consecutive months. Based on the climate indices, the best correlation results occurred in the years with high rainfall, coinciding with the occurrence of negative dipole and of La Niña. Therefore, climate indices can indicate the possible predictive capacity of extreme rainfall events. The results show that the influence of climatic phenomena is more pronounced in the northern region of the Tapajós River Basin.
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McClain, Michael E., and Rosa E. Cossío. "The use of riparian environments in the rural Peruvian Amazon." Environmental Conservation 30, no. 3 (September 2003): 242–48. http://dx.doi.org/10.1017/s0376892903000237.
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River margins are valued for agriculture in the western Amazon because of their fertile soils and level surfaces. Riparian forests along river margins also provide valuable ecosystem services by protecting water quality and providing resources to aquatic organisms. Because inhabitants of the region rely on these aquatic resources, riparian deforestation may have unintended negative feedbacks on the health and well-being of rural communities. A survey of 79 households of mixed cultural background investigated how riparian environments were used, what mechanisms were in place for their conservation, and how local people valued them. Corn, beans and peanuts were cultivated preferentially in riparian areas, complementing the manioc and plantains grown on upland soils. People valued riparian areas for their ecosystem services and generally left a protective buffer of forest along rivers. Both the agricultural and ecological values of riparian areas may be preserved through proper management.
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Mu, Linquan, Jaime B. Palter, and Hongjie Wang. "Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed." Biogeosciences 20, no. 10 (May 26, 2023): 1963–77. http://dx.doi.org/10.5194/bg-20-1963-2023.
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Abstract. The Amazon River plume plays a critical role in shaping the carbonate chemistry over a vast area in the western tropical North Atlantic. We conduct a sensitivity analysis of hypothetical ocean alkalinity enhancement (OAE) via quicklime addition in the Amazon River watershed, examining the response of carbonate chemistry and air–sea carbon dioxide flux to the alkalinity addition. Through a series of sensitivity tests, we show that the detectability of the OAE-induced alkalinity increment depends on the perturbation strength (or size of the alkalinity addition, ΔTA) and the number of samples: there is a 90 % chance to meet a minimum detectability requirement with ΔTA>15 µmol kg−1 and sample size >40, given background variability of 15–30 µmol kg−1. OAE-induced pCO2 reduction at the Amazon plume surface would range between 0–25 µatm when ΔTA=20 µmol kg−1, decreasing with increasing salinity (S). Adding 20 µmol kg−1 of alkalinity at the river mouth could elevate the total carbon uptake in the Amazon River plume (15<S<35) by at least 0.07–0.1 Mt CO2 per month, and a major portion of the uptake would occur in the saltiest region (S>32) due to its large size, comprising approximately 80 % of the S>15 plume area. However, the lowest-salinity region (S<15) has a greater drop in surface ocean partial pressure of CO2 (pCO2sw) due to its low buffer capacity, potentially allowing for observational detectability of pCO2sw reduction in this region. Reduced outgassing in this part of the plume, while more uncertain, may also be important for total additional CO2 uptake. Such sensitivity tests are useful in designing minimalistic field trials and setting achievable goals for monitoring, reporting, and verification purposes.
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Campos, C. P., M. F. Catarino, and C. E. C. Freitas. "Stock assessment of the peacock bass Cichla temensis (Humboldt, 1821), an important fishing resource from the middle Negro river, Amazonas, Brazil." Brazilian Journal of Biology 80, no. 3 (September 2020): 506–10. http://dx.doi.org/10.1590/1519-6984.203124.
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Abstract Peacock bass Cichla temensis is an important species at the Amazon basin, since commercial, subsistence and recreational fisheries simultaneously exploit it. Cichla temensis is the preferred species by recreational fishers and it has been strongly exploited, mainly at the Negro river, the second largest tributary of the Amazon River. It was used data from experimental fisheries, collected at the middle stretch of Negro river, which were coupled with previously published data on its population dynamics, to run a yield per recruit model and build scenarios of sustainable fisheries. The results showed that the age of the first catch is a key variable to successful management of the peacock bass stocks at this region.
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Costa, Marcondes, Luiz Carvalho, Patricia Pereira, and Glayce Valente. "IMPACTS OF URBAN DEVELOPMENT ON AN OXBOW LAKE IN THE AMAZON REGION: LANDSCAPE AND GEOCHEMICAL EVIDENCE." BOLETIM DO MUSEU DE GEOCIÊNCIAS DA AMAZÔNIA 7 (2020), no. 2 (December 1, 2020): 1–12. http://dx.doi.org/10.31419/issn.2594-942x.v72020i2a6mlc.
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Amapá Lake is an abandoned meander of the Acre River, the margins of which are occupied by agricultural settlements, smallholdings, fish farms and dirt roads. This paper discusses the impact of this occupation on the lake area based on field data and physical-chemical and elementary chemical analyses of the lake and river waters. The strong physical changes in the lake landscape have impacted the quality of its water. During the dry season (low water), when the temperature of the water reaches 30-34ºC, there is a proliferation of green algae and in the area affected by fish farms and smallholdings there is an increase in total dissolved solids, electrical conductivity, and transparency, while turbidity and total suspended solids become more concentrated during the flood season. The anthropogenic impact is also indicated by the higher levels of ammonia, chlorides, bromides, and phosphates in the water. However, the concentrations of dissolved metal ions are all consistent with those found in the Acre River, and other muddy water lakes and rivers in the Amazon basin, reflecting the mineralogy of the suspended material. The concentrations of most heavy metals (Pb, Cu, (Zn), Cd and Hg) are below 0.01 mg L-1, while that of Hg (0.006 mg L-1) is above the recommended limits for human consumption. Overall, the results of the study indicate that Amapá Lake is suffering ongoing impacts (physical and chemical) from urban development, which are mitigated by the periodic flooding of the river. Key words: Urban expansion, Environmental impacts, Waters, Heavy metals.
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Behling, Hermann, and Marcondes Lima da Costa. "Holocene Environmental Changes from the Rio Curuá Record in the Caxiuanã Region, Eastern Amazon Basin." Quaternary Research 53, no. 3 (May 2000): 369–77. http://dx.doi.org/10.1006/qres.1999.2117.
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AbstractHolocene environments have been reconstructed by multiproxy studies of an 850-cm-long core from Rio Curuá dating to >8000 14C yr B.P. The low-energy river lies in the eastern Amazon rain forest in the Caxiuanã National Forest Reserve, 350 km west of Belem in northern Brazil. Sedimentological, mineralogical, and geochemical dates demonstrate that the deposits correspond to two different environments, sediments of an active river before 8000 14C yr B.P. and later a passive river system. The pollen analytical results indicate four different local and regional Holocene paleoenvironmental periods: (1) a transition to a passive fluvial system and a well-drained terra firme (unflooded upland) Amazon rain forest with very limited development of inundated forests (várzea and igapó) (>7990–7030 14C yr B.P.); (2) a sluggish river with a local Mauritia palm-swamp and similar regional vegetation, as before (7030–5970 14C yr B.P.); (3) a passive river, forming shallow lake conditions and with still-abundant terra firme forest in the study region (5970–2470 14C yr B.P.); and (4) a blocked river with high water levels and marked increase of inundated forests during the last 2470 14C yr B.P. Increased charcoal during this last period suggests the first strong presence of humans in this region. The Atlantic sea level rise was probably the major factor in paleoenvironmental changes, but high water stands might also be due to greater annual rainfall during the late Holocene.
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Varona, Humberto L., Julia Araujo, Moacyr Araujo, and Marcus Silva. "Idealized hydrodynamical numerical model dataset with no-river runoff at the western tropical North Atlantic." Open Research Europe 3 (April 28, 2023): 67. http://dx.doi.org/10.12688/openreseurope.15747.1.
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The western tropical North Atlantic (WTNA) is a very complex region, with the influence of intense western boundary currents in connection with equatorial zonal currents, important atmospheric forcings (e.g Intertropical Convergence Zone), mesoscale activities (e.g NBC rings), and the world’s largest river discharge as the Amazon River runoff. The volume discharge is equivalent to more than one-third of the Atlantic river freshwater input, with a plume that spreads over the region reaching the northwestward Caribbean Sea and eastward longitudes of 30°W, and influencing from physical to biological structures. Therefore, in order to enable and encourage more understanding of the region, here we present a dataset based on an idealized scenario of no river runoff of the Amazon River and Par ́a River in the WTNA. The numerical simulations were conducted with a regional oceanic modeling system (ROMS) model and three pairs of files were generated with the model outputs: (i) ROMS-files, with the parameters of the ROMS-outputs raw data in a NetCDF format and monthly and weekly frequencies; (ii) MATLAB-files, which contain oceanographic parameters also in monthly and weekly frequencies; and (iii) NetCDF-files, with oceanographic parameters again in monthly and weekly frequencies. For each file, we present the coordinates and variable names, descriptions, and correspondent units. The dataset is available in the Science Data Bank repository (doi: https://doi.org/10.57760/sciencedb.02145)
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Da Silva, Isomar Lima, Marcus Vinicius Marins Melo, Vladimir Quéops Gameleira Nunes, and Frank Choite Ikuno. "The sustainable potential of hydrokinetic turbines in the Amazon basin." OBSERVATÓRIO DE LA ECONOMÍA LATINOAMERICANA 21, no. 9 (September 26, 2023): 13216–52. http://dx.doi.org/10.55905/oelv21n9-149.
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The Amazon, rich in biodiversity and natural resources, seeks renewable energy sources to minimize environmental impacts and reduce dependence on non-renewable sources. Hydrokinetic turbines emerge as a promising alternative by making it possible to convert the kinetic energy of river currents into electricity, without the need for dams. This study focuses on exploring the sustainable potential of hydrokinetic turbines in the Amazon region. For this, a prototype hydroelectric power plant that uses a hydrokinetic turbine was developed, and the feasibility of this technology as a renewable energy source was examined. The research included 3D modeling and propeller printing for the prototype, using materials such as carbon steel and 3D printing. The electrical components were dimensioned according to current technical standards, including cables, circuit breakers, batteries and converters. The methodology included tests on the real environment of a river in the Amazon region, evaluating the power generation capacity and the adaptability of the system to local conditions. The results demonstrated that the prototype is capable of producing electrical energy efficiently, taking advantage of the strength of river currents. The flexibility of the blades allowed adjustments according to the geometry of the watercourse, increasing the versatility of the system. In addition, the modular approach of turbines has shown promise for scalability and installation in different scenarios. This study contributes to the understanding of the potential of hydrokinetic turbines in the Amazon region, offering a renewable solution for electricity generation. The combination of technologies such as 3D printing, structural and electrical modeling has resulted in a prototype adaptable to local conditions, with the potential to provide clean energy to riverine communities, reducing dependence on non-renewable sources and promoting the sustainable development of the region.
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Frederico, Renata G., Izeni P. Farias, Maria Lúcia Góes de Araújo, Patricia Charvet-Almeida, and José A. Alves-Gomes. "Phylogeography and conservation genetics of the Amazonian freshwater stingray Paratrygon aiereba Müller & Henle, 1841 (Chondrichthyes: Potamotrygonidae)." Neotropical Ichthyology 10, no. 1 (2012): 71–80. http://dx.doi.org/10.1590/s1679-62252012000100007.
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The family Potamotrygonidae is monophyletic comprising three genera: Paratrygon Duméril, Potamotrygon Garman and Plesiotrygon Rosa, Castello & Thorson. The distribution of most species in this family is restricted to a single basin or fluvial system. Only Potamotrygon motoro, Potamotrygon orbignyi and Paratrygon aiereba are found in more than one river basin. In this study we investigate genetic structuring of Paratrygon aiereba, from five rivers of the Amazon region: Negro, Solimões-Amazon-Estuary system, Tapajós, Xingu and Araguaia. Sixty-three individuals were sequenced for ATPase 6, and a representative subsample of 27 individuals was sequenced for COI. The COI dataset analysis indicated that Paratrygon is sister to all other potamotrygonid genera and species. Population parameters inferred from the analysis of ATPase 6 sequences revealed that the populations of this species are structured within each river, with no or nearly non-existent gene flow occurring between rivers and a positive correlation between geographic and genetic distances. Paratrygon aiereba is comprised of three geographically restricted clades with K2P interclade distances of at least 2%. Intraspecific divergence within P. aiereba is similar to the interspecific divergence observed in Potamotrygon spp. sampled throughout the same geographic area. Using the premises of COI barcoding and the allopatric distribution of the three P. aiereba clades, the taxon P. aiereba most likely comprises three distinct biological species. Since freshwater stingrays of the family Potamotrygonidae are highly exploited for the aquarium trade, management and conservation strategies need to be implemented at the level of each river basin, rather than at the level of the Amazon basin.
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Costa, Wilson, Pedro Amorim, and Pedro H. N. Bragança. "A new miniature killifish of the genus Melanorivulus (Cyprinodontiformes: Rivulidae) from the Xingu river drainage, Brazilian Amazon." Vertebrate Zoology 64, no. 2 (July 15, 2014): 193–97. http://dx.doi.org/10.3897/vz.64.e31479.
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Melanorivulus rubroreticulatus, new species, is described on the basis of material collected in the lower section of the Xingu river drainage, Brazilian Amazon. It is a member of a group endemic to the region encompassing the southern Amazonas river tributaries and the Parnaíba river basin. The new species is distinguished from other congeners of this group by the presence of broad red bars on the caudal fin in males, bars often interconnected to form reticulations, and short red bars contrasting with intense light blue ground colour on the anal-fin base. It represents the northern-most record for the group, besides being the only species occurring in the Amazon rain forest and possibly is also the smallest one, barely surpassing 25 mm of standard length.
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PRUDENTE, Bruno da S., Pedro CARNEIRO-MARINHO, Roberta de M. VALENTE, and Luciano F. de A. MONTAG. "Feeding ecology of Serrasalmus gouldingi (Characiformes: Serrasalmidae) in the lower Anapu River region, Eastern Amazon, Brazil." Acta Amazonica 46, no. 3 (September 2016): 259–70. http://dx.doi.org/10.1590/1809-4392201600123.
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Abstract Studies on feeding ecology of fishes are important to understand the relationship between species and environmental seasonal variations. In tropical rivers, these relationships are mainly modeled by hydrological patterns. Thereby, this study aimed to assess the influence of fluviometric variation and life stage (juveniles and adults) in the feeding ecology of Serrasalmus gouldingi in the lower Anapu River region, located in Eastern Amazon, Pará, Brazil. Specimens were collected bimonthly, considering four different hydrological periods. We assessed the diet composition, feeding intensity and niche breadth of the species. Thirty-two dietary items were identified and grouped into ten categories. A total of 279 stomachs were analyzed, showing a predominance of fish fragments, followed by fruits and seeds. The diet composition of S. gouldingi differed only between drought and flood season, although it did not differ between juveniles and adults. An increase in feeding intensity was recorded during the rise in the water level, with a lower feeding intensity observed during transitional season. Serrasalmus gouldingi showed lower niche breadth during flood season, attributed to the high consumption of fruits and seeds, presenting an omnivorous diet with high tendency towards piscivory. Although less evident than in other Amazon watersheds, the flood pulse in the lower Anapu River region is an important factor influencing the feeding ecology of the species.
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Rostain, Stéphen. "WHERE THE AMAZON RIVER MEETS THE ORINOCO RIVER. ARCHAEOLOGY OF THE GUIANAS." Amazônica - Revista de Antropologia 4, no. 1 (June 16, 2012): 10. http://dx.doi.org/10.18542/amazonica.v4i1.880.
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Archaeological and interdisciplinary investigations conducted in the Guianas during these last 35 years offer a new picture of the pre-Columbian Guianas. Although archaeology still is relatively incipient in the Guianas, it is possible to draw up a panorama of the prehistory of this huge region. During the last millennium before the European Conquest, Guianas coast was divided into two main territories dominated by two different cultural entities. Cayenne Island in French Guiana was the key-area marking the boundary between two cultural traditions. Western coast up to the Guyana was dominated by cultures linked to the Arauquinoid Tradition originated in the Middle Orinoco. Eastern coast was occupied by cultures belonging to the Polychrome Tradition of the Lower Amazon. These two cultural entities grew up from ca. AD 600 up to their destruction by the European Conquest. Keywords: Archaeology, Guianas, arauquinoid tradition, polychrome tradition
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Heckenberger, Michael J., J. Christian Russell, Joshua R. Toney, and Morgan J. Schmidt. "The legacy of cultural landscapes in the Brazilian Amazon: implications for biodiversity." Philosophical Transactions of the Royal Society B: Biological Sciences 362, no. 1478 (January 8, 2007): 197–208. http://dx.doi.org/10.1098/rstb.2006.1979.
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For centuries Amazonia has held the Western scientific and popular imagination as a primordial forest, only minimally impacted by small, simple and dispersed groups that inhabit the region. Studies in historical ecology refute this view. Rather than pristine tropical forest, some areas are better viewed as constructed or ‘domesticated’ landscapes, dramatically altered by indigenous groups in the past. This paper reviews recent archaeological research in several areas along the Amazon River with evidence of large pre-European ( ca 400–500 calendar years before the present) occupations and large-scale transformations of forest and wetland environments. Research from the southern margins of closed tropical forest, in the headwaters of the Xingu River, are highlighted as an example of constructed nature in the Amazon. In all cases, human influences dramatically altered the distribution, frequency and configurations of biological communities and ecological settings. Findings of historical change and cultural variability, including diverse small to medium-sized complex societies, have clear implications for questions of conservation and sustainability and, specifically, what constitutes ‘hotspots’ of bio-historical diversity in the Amazon region.
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VASCONCELOS DE SALES, RAQUEL. "A IMPORTÂNCIA DO TRÁFEGO AQUAVIÁRIO NO NORTE DO BRASIL." Revista Científica Semana Acadêmica 12, no. 244 (March 26, 2024): 1–29. http://dx.doi.org/10.35265/2236-6717-244-12936.
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Water transport plays an essential role in economic progress and regional cohesion, especially in the vast Northern region of Brazil, characterized by extensive territorial extensions and the presence of imposing rivers, such as the Amazon. This form of transport is a strategic route for the movement of goods and passengers, connecting remote regions and contributing to logistical efficiency. Due to the lack of land infrastructure in certain areas, rivers become crucial routes for commerce, facilitating access to isolated communities and stimulating economic exchanges. To this end, the present study aims to analyze strategies to optimize waterway traffic management in the North of Brazil, aiming to reconcile economic development with environmental preservation and the well-being of riverside communities. The justification for this research lies in the strategic importance of waterway traffic in this region, marked by a vast territorial extension and imposing rivers such as the Amazon. The complexity of the Amazonian scenario, combined with the scarcity of in-depth studies on the topic, highlights the need for a balanced approach that promotes economic development without compromising river ecosystems and the quality of life of local populations. The methodology adopted combines extensive bibliographical research and qualitative data analysis, exploring academic sources and conducting interviews with relevant stakeholders. This study seeks to fill gaps in existing knowledge, contributing to support public policies and sustainable practices in the management of waterway traffic in the Northern region of Brazil.
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de Linage, C., J. S. Famiglietti, and J. T. Randerson. "Statistical prediction of terrestrial water storage changes in the Amazon Basin using tropical Pacific and North Atlantic sea surface temperature anomalies." Hydrology and Earth System Sciences 18, no. 6 (June 4, 2014): 2089–102. http://dx.doi.org/10.5194/hess-18-2089-2014.
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Abstract. Floods and droughts frequently affect the Amazon River basin, impacting transportation, agriculture, and ecosystem processes within several South American countries. Here we examine how sea surface temperature (SST) anomalies influence interannual variability of terrestrial water storage anomalies (TWSAs) in different regions within the Amazon Basin and propose a statistical modeling framework for TWSA prediction on seasonal timescales. Three simple semi-empirical models forced by a linear combination of lagged spatial averages of central Pacific and tropical North Atlantic climate indices (Niño 4 and TNAI) were calibrated against a decade-long record of 3°, monthly TWSAs observed by the Gravity Recovery And Climate Experiment (GRACE) satellite mission. Niño 4 was the primary external forcing in the northeastern region of the Amazon Basin, whereas TNAI was dominant in central and western regions. A combined model using the two indices improved the fit significantly (p < 0.05) for at least 64% of the grid cells within the basin, compared to models forced solely with Niño 4 or TNAI. The combined model explained 66% of the observed variance in the northeastern region, 39% in the central and western region, and 43% for the Amazon Basin as a whole, with a 3-month lead time between the climate indices and the predicted TWSAs. Model performance varied seasonally: it was higher than average during the wet season in the northeastern Amazon and during the dry season in the central and western region. The predictive capability of the combined model was degraded with increasing lead times. Degradation rates were lower in the northeastern Amazon (where 49% of the variance was explained using an 8-month lead time versus 69% for a 1-month lead time) compared to the central and western Amazon (where 22% of the variance was explained at 8 months versus 43% at 1 month). These relationships may contribute to an improved understanding of the climate processes regulating the spatial patterns of flood and drought risk in South America.
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Lopes, Gerson P., Tamily C. M. Santos, and Paúl M. Velazco. "First record of Vampyrodes caraccioli (Thomas, 1889) (Chiroptera, Phyllostomidae) in the state of Amazonas and its updated distribution in Brazil." Check List 12, no. 3 (June 22, 2016): 1909. http://dx.doi.org/10.15560/12.3.1909.
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Abstract: The present note reports the first record of Vampyrodes caraccioli in the Brazilian state of Amazonas, and the central Amazon region, based on 44 specimens caught in the Auati-Paraná Extractive Reserve, north bank of the Solimões/Amazonas River. Our record fills a distribution gap of this species in the Brazilian Amazon and illustrates that the current knowledge on the distribution of Amazonian bats is far from complete.
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Ferreira Filho, David Figueiredo, and Francisco Carlos Lira Pessoa. "Homogeneous regions of precipitation trends across the Amazon River Basin, determined from the Global Precipitation Climatology Centre - GPCC." Revista Brasileira de Geografia Física 17, no. 2 (March 14, 2024): 1283–308. http://dx.doi.org/10.26848/rbgf.v17.2.p1283-1308.
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Space-temporal patterns of precipitation are influenced by complex interactions between changes in climate and land cover. The Amazon River Basin has local and global impacts regarding the hydrological cycle; therefore, it is critical to understand how precipitation patterns and intensity are changing. The objective of this study was to analyze precipitation trends and form homogeneous regions of precipitation trends in the Amazon River Basin using the data set of precipitation data from the meteorological satellite Global Precipitation Climatology Center (GPCC), applying non-parametric methods (Mann-Kendall, Spearman and Sen slope) and fuzzy C-means to identify specific regions that are experiencing changes in hydrological patterns. The results show changes in rainfall behavior over time and in the intensity of events. The statistics applied to form clusters resulted in 6 well-divided homogeneous groups, each with unique characteristics. Specifically, the central-southern areas of the basin showed negative trends in precipitation (-1.17 mm/year) forming a homogeneous region (HR1), while in the northern region there was an increasing trend in precipitation (2.73 mm/year). In general, over the 37 years studied, the wetlands tended to become wetter and the dry areas drier. Other homogeneous regions presented their own results and unique characteristics, which agree with other studies
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Rodríguez-Zorro, Paula A., Bruno Turcq, Renato C. Cordeiro, Luciane S. Moreira, Renata L. Costa, Crystal H. McMichael, and Hermann Behling. "Forest stability during the early and late Holocene in the igapó floodplains of the Rio Negro, northwestern Brazil." Quaternary Research 89, no. 1 (December 21, 2017): 75–89. http://dx.doi.org/10.1017/qua.2017.99.
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AbstractLocated at the northwestern part of the Amazon basin, Rio Negro is the largest black-water river in the world and is one of the poorest studied regions of the Amazon lowlands. In the middle-upper part of the Rio Negro were retrieved sediment cores form Lake Acarabixi, which were analyzed using pollen, spores, charcoal, and geochemistry. The aim of this study was to detect the influences from humans and river dynamics on the vegetation history in the region. Two main periods of vegetation and river dynamics were detected. From 10,840 to 8240 cal yr BP, the river had a direct influence into the lake. The lake had a regional input of charcoal particles, which reflected the effect of the dry Holocene period in the basin. Furthermore, highland taxa such asHedyosmumandMyrsinewere found at that time along with igapó forest species that are characteristic to tolerate extended flooding likeEschweilera,Macrolobium, Myrtaceae,Swartzia, andAstrocaryum. During the late Holocene (1600 to 650 cal yr BP), more lacustrine phases were observed. There were no drastic changes in vegetation but the presence of pioneer species likeVismiaandCecropia, along with the signal of fires, which pointed to human disturbances.