Rivers are natural biogeochemical systems shaping the fates of dissolved organic matter (DOM) from leaving soils to reaching the oceans. This study focuses on Amazon basin DOM processing employing negative and positive electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI[±] FT-ICR MS) and nuclear magnetic resonance spectroscopy (NMR) to reveal effects of major processes on the compositional space and structural characteristics of black, white and clear water systems. These include non-conservative mixing at the confluences of (1) Solimões and the Negro River, (2) the Amazon River and the Madeira River, and (3) in-stream processing of Amazon River DOM between the Madeira River and the Tapajós River. The Negro River (black water) supplies more highly oxygenated and high molecular weight compounds, whereas the Solimões and Madeira Rivers (white water) contribute more CHNO and CHOS molecules to the Amazon River main stem. Aliphatic CHO and abundant CHNO compounds prevail in Tapajos River DOM (clear water), likely originating from primary production. Sorption onto particles and heterotrophic microbial degradation are probably the principal mechanisms for the observed changes in DOM composition in the Amazon River and its tributaries.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.scitotenv.2022.159620 | DOI Listing |
Sensors (Basel)
January 2025
Electronic and Information Technology Research and Development Center (CETELI), Federal University of Amazonas, Manaus 69067-005, AM, Brazil.
The Amazon region has the largest hydrographic basin in the world. The rivers act as roads, and boats serve as vehicles for transporting passengers and cargo to large urban centers, municipalities, riverside communities, villages, and settlements. The Amazon River transportation system faces critical gaps due to the lack of land infrastructure in certain areas, which makes rivers essential for commerce and access to isolated communities.
View Article and Find Full Text PDFInt J Environ Res Public Health
January 2025
Programa de Pós-Graduação em Saúde Coletiva, Instituto de Estudos em Saúde Coletiva, Universidade Federal do Rio de Janeiro (IESC/UFRJ), Rio de Janeiro 21941-901, Brazil.
Environmental exposure to metallic contaminants such as barium (Ba) is a worldwide concern, as these metals can even be toxic to the human body. Data on different sources of exposure to Ba and possible routes of entry are important for preventing adverse health effects. Blood Ba levels were evaluated in 10 localities in the cities of Barcarena and Abaetetuba in the Amazon.
View Article and Find Full Text PDFSci Rep
January 2025
Universidade Federal de Ouro Preto, Ouro Preto, MG, Brasil.
The South American Transcontinental Drainage Divide (TDD) is roughly oriented NE-SW from its Atlantic termination in SE Brazil to its NW termination in the limits between the southwestern edges of the Amazon Craton and the Andean Foreland. Based on a weak spatial coincidence with 90 - 70 Ma igneous intrusions, the origin and stability of the TDD have been attributed to intraplate magmatic activity. Using geomorphic analysis of drainage divides, we infer an overall southward migration of the TDD, even in areas with constrained uplift associated with intrusions.
View Article and Find Full Text PDFJ Environ Manage
January 2025
Geotechnologies in Soil Sciences Research Group - GeoCiS, Department of Soil Science, Luiz de Queiroz College of Agriculture - Esalq, University of São Paulo - USP, Piracicaba, São Paulo, Brazil. Electronic address:
Analyzing soil in large and remote areas such as the Amazon River Basin (ARB) is unviable when it is entirely performed by wet labs using traditional methods due to the scarcity of labs and the significant workforce requirements, increasing costs, time, and waste. Remote sensing, combined with cloud computing, enhances soil analysis by modeling soil from spectral data and overcoming the limitations of traditional methods. We verified the potential of soil spectroscopy in conjunction with cloud-based computing to predict soil organic carbon (SOC) and particle size (sand, silt, and clay) content from the Amazon region.
View Article and Find Full Text PDFEnviron Monit Assess
January 2025
Programa de Pós-Graduação em Ecologia (PPGECO), Universidade Federal do Pará (UFPA), Instituto de Ciências Biológicas (UFPA), Belém, Pará, Brazil.
Freshwater ecosystems under the influence of human activities are subject to multiple environmental stressors that lead to biodiversity loss and habitat modification. In recent years, various organisms have been used as bioindicators to detect environmental changes by their ability to perceive changes in community attributes. A good example is the semiaquatic bugs (Hemiptera, infra order Gerromorpha) that act as predators and are sensitive to subtle changes in environmental conditions.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!