| Dissolved nitrogen in rivers: comparing pristine and impacted regions of Brazil. | |
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MedLine Citation:
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PMID: 21085777 Owner: NLM Status: In-Process |
Abstract/OtherAbstract:
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Riverine nitrogen distribution is increasingly controlled by anthropogenic activities in their watersheds, regardless of spatial scale, climate, and geographical zone. Consequently, modelling efforts to predict the export of nitrogen from rivers worldwide have used attributes such as population density, land use, urbanization and sanitation. These models have greatly enhanced our understanding of the sources and fate of nitrogen added to terrestrial systems and transported to rivers and streams, especially for developed countries of the North temperate zone. However, much of the world's population lives in developing countries of the tropics, where the effects of human activities on riverine N exports are still poorly understood. In an effort to close this gap, we compare riverine nitrogen data from 32 Brazilian rivers draining two contrasting regions in this tropical country in terms of economic development - the State of São Paulo and the Amazon. Our data include nitrogen in different dissolved forms, such as Dissolved Inorganic Nitrogen (DIN) and Dissolved Organic Nitrogen (DON). The results show that nitrogen concentrations decreased as river runoff increased in both study areas, and that concentrations were significantly higher in rivers draining the most economically developed region. The relationships between nitrogen concentrations and fluxes with demographic parameters such as population density were also determined and compared to those in temperate systems. In contrast to temperate watersheds, we found that nitrogen fluxes increased only after population densities were higher than 10 individuals per km². |
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Authors:
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L A Martinelli; L D Coletta; E C Ravagnani; P B Camargo; J P H B Ometto; S Filoso; R L Victoria |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Brazilian journal of biology = Revista brasleira de biologia Volume: 70 ISSN: 1678-4375 ISO Abbreviation: Braz J Biol Publication Date: 2010 Oct |
Date Detail:
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Created Date: 2010-11-18 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101129542 Medline TA: Braz J Biol Country: Brazil |
Other Details:
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Languages: eng Pagination: 709-22 Citation Subset: IM |
Affiliation:
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Centro de Energia Nuclear na Agricultura – CENA, Universidade de São Paulo – USP, Av. Centenário, 303, CEP 13416-000, Piracicaba, SP, Brazil. martinelli@cena.usp.br |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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