Search results for "Amazonian"
showing 10 items of 18 documents
Record-breaking warming and extreme drought in the Amazon rainforest during the course of El Niño 2015–2016
2016
AbstractThe El Niño-Southern Oscillation (ENSO) is the main driver of interannual climate extremes in Amazonia and other tropical regions. The current 2015/2016 EN event was expected to be as strong as the EN of the century in 1997/98, with extreme heat and drought over most of Amazonian rainforests. Here we show that this protracted EN event, combined with the regional warming trend, was associated with unprecedented warming and a larger extent of extreme drought in Amazonia compared to the earlier strong EN events in 1982/83 and 1997/98. Typical EN-like drought conditions were observed only in eastern Amazonia, whilst in western Amazonia there was an unusual wetting. We attribute this wet…
Pharmaceuticals and other urban contaminants threaten Amazonian freshwater ecosystems
2021
Abstract Urban areas in the Brazilian Amazon have grown at an unprecedented rate during the last years. About 90% of the wastewater produced by these urban areas are discharged untreated into Amazonian freshwater ecosystems, constituting a potential environmental pathway for pharmaceuticals and other chemicals consumed by modern societies (e.g. psychostimulants, personal-care products, hormones). The distribution of these chemicals into the Amazon River and their potential risks for freshwater biodiversity have not been evaluated so far. Here, we show the results of the largest chemical monitoring campaign conducted in the Amazon region. We assessed exposure patterns for 43 pharmaceuticals …
Land cover and its transformation in the backward trajectory footprint region of the Amazon Tall Tower Observatory
2019
Abstract. The Amazon rain forest experiences the combined pressures from human-made deforestation and progressing climate change, causing severe and potentially disruptive perturbations of the ecosystem's integrity and stability. To intensify research on critical aspects of Amazonian biosphere–atmosphere exchange, the Amazon Tall Tower Observatory (ATTO) has been established in the central Amazon Basin. Here we present a multi-year analysis of backward trajectories to derive an effective footprint region of the observatory, which spans large parts of the particularly vulnerable eastern basin. Further, we characterize geospatial properties of the footprint regions, such as climatic condition…
Systematics of the Boana semilineata species group (Anura: Hylidae), with a description of two new species from Amazonian Ecuador
2020
Abstract The combination of genetic and phenotypic characters for species delimitation has allowed the discovery of many undescribed species of Neotropical amphibians. In this study, we used DNA sequences (genes 12S, 16S, ND1 and COI) and morphologic, bioacoustic and environmental characters of the Boana semilineata group to evaluate their phylogenetic relationships and assess their species limits. In addition, we included DNA sequences of several species of Boana to explore cryptic diversity in other groups. We found three Confirmed Candidate Species (CCS) within the B. semilineata group. Holotype examination of Hyla appendiculata shows that it is a valid species that corresponds to one of…
Doing archaeology and working with Amazonian communities: the case of the earthen structures known as geoglyphs
2018
The project of study of earthen structures known as geoglyphs led by the universities of Valencia (Spain) and the Federal University of Acre (Rio Branco, Brazil) has different objectives but the main one, beyond, the study of the structures is the implementation of plans that allow the necessary protection of these monuments having an impact on local communities. The project pretends to move away from interventions that could be labeled as ‘neocolonialist’ and contribute to the development of archaeological activity in the state of Acre. For this, it has the collaboration of the Acrean delegation of the Instituto de Patrimonio Histórico Artístico (IPHAN), la fundación Elías Mansur de Cultur…
African volcanic emissions influencing atmospheric aerosols over the Amazon rain forest
2018
Long-range transport (LRT) plays an important role in the Amazon rain forest by bringing in different primary and secondary aerosol particles from distant sources. The atmospheric oxidation of dimethyl sulfide (DMS), emitted from marine plankton, is considered an important sulfate source over the Amazon rain forest, with a lesser contribution from terrestrial soil and vegetation sulfur emissions. Volcanic sulfur emissions from Africa could be a source of particulate sulfate to the Amazonian atmosphere upon transatlantic transport but no observations have been published. By using satellite observations, together with ground‑based and airborne aerosol particle observations, this paper provide…
Amazonian biomass burning-derived acid and nutrient deposition in the north Andean montane forest of Ecuador
2008
[1] We explored the influence of biomass burning in Amazonia and northeastern Latin America on N, C, P, S, K, Ca, Mg, Al, Mn, and Zn cycles of an Andean montane forest in south Ecuador exposed to the Amazon basin between May 1998 and April 2003. We assessed the response of the element budget of three microcatchments (8–13 ha) to the variations in atmospheric deposition between the intensive burning season and outside the burning season in Amazonia. There were significantly elevated H, N, and Mn depositions during biomass burning. Elevated H deposition during biomass burning caused elevated base metal loss from the canopy and the organic horizon and deteriorated already low base metal supply…
Preliminary results of the 2017 season in the Amazonian earthen structures known as geoglyphs.
2018
O trabalho realizado pela equipe de pesquisa multidisciplinar, liderada pela Universitat de Valencia Estudi General (UVEG) e a Universidade Federal do Acre (UFAC), de detalhamento da topografia, em especial na RESEX Chico Mendes, criou progresso significativo no conhecimento das estruturas de terra construídas na paisagem amazônica, conhecidas popularmente como geoglifos, no que se refere a aplicação de topografia de alta precisão para algumas das estruturas, compreensão geral fenômeno e aplicação de uma nova estratégia de pesquisa, com o auxílio de ferramentas como o Google Earth, Google Maps, GPX, OpenStreetMap e Lidar. Ainda há muito trabalho de campo a ser feito na Amazônia Ocidental, n…
Sensitivities of Amazonian clouds to aerosols and updraft speed
2017
Abstract. The effects of aerosol particles and updraft speed on warm-phase cloud microphysical properties are studied in the Amazon region as part of the ACRIDICON-CHUVA experiment. Here we expand the sensitivity analysis usually found in the literature by concomitantly considering cloud evolution, putting the sensitivity quantifications into perspective in relation to in-cloud processing, and by considering the effects on droplet size distribution (DSD) shape. Our in situ aircraft measurements over the Amazon Basin cover a wide range of particle concentration and thermodynamic conditions, from the pristine regions over coastal and forested areas to the southern Amazon, which is highly poll…
Intercomparison of remote-sensing based evapotranspiration algorithms over amazonian forests
2019
Abstract Evapotranspiration (ET) is considered a key variable in the understanding of the Amazonian tropical forests and their response to climate change. Remote-Sensing (RS) based evapotranspiration models are presented as a feasible means in order to provide accurate spatially-distributed ET estimates over this region. In this work, the performance of four commonly used ET RS models was evaluated over Amazonia using Moderate Resolution Imaging Spectroradiometer (MODIS) data. RS models included i) Priestley-Taylor Jet Propulsion Laboratory (PT-JPL), ii) Penman-Monteith MODIS operative parametrization (PM-Mu), iii) Surface Energy Balance System (SEBS), and iv) Satellite Application Facility…