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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Intra and interannual variability in the Madeira River water chemistry and sediment load

Texto completo
Autor(es):
Leite, Nei K. [1] ; Krusche, Alex V. [1] ; Ballester, Maria V. R. [1] ; Victoria, Reynaldo L. [1] ; Richey, Jeffrey E. [2] ; Gomes, Beatriz M. [3]
Número total de Autores: 6
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, CENA, BR-13416903 Piracicaba, SP - Brazil
[2] Univ Washington, Sch Oceanog, Seattle, WA 98195 - USA
[3] UNIR, BR-78960000 Ji Parana, RO - Brazil
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: BIOGEOCHEMISTRY; v. 105, n. 1-3, p. 37-51, SEP 2011.
Citações Web of Science: 15
Resumo

Concentrations of cations (Na(+), Ca(2+), Mg(2+), K(+), NH(4) (+)), anions (HCO(3) (-), Cl(-), NO(3) (-), SO(4) (2-), PO(4) (3-)) and suspended sediments in the Madeira River water were determined near the city of Porto Velho (RO), in order to assess variation in water chemistry from 2004 to 2007. Calcium and bicarbonate were the dominant cation and anion, respectively. Significant seasonal differences were found, with highest concentrations occurring during the dry season, as expected from the drainage of Andean carbonate-rich substratum. Interannual variations were also observed, but became significant only when annual average discharge was 25% less than normal. Under this atypical discharge condition, bicarbonate was replaced by sulfate, and higher suspended sediment concentrations and loads were also observed. Compared to previously published studies, it appears that no significant changes in water chemistry have occurred during the last 20-30 years, although differences in approaches and sampling designs among this and previous studies may not allow detection of modest changes. The calculated suspended sediment load reported here is close to the values presented elsewhere, reinforcing the relative importance of this river as a sediment supplier for the Amazon Basin. Seasonality has a significant control on the chemistry of Madeira River waters, and severe decrease in discharge due to anthropogenic changes, such as construction of reservoirs or the occurrence of drier years-a plausible consequence of global climate change-may lead to modification in the chemical composition as well in the sediment deliver to the Amazon River. (AU)

Processo FAPESP: 03/13172-2 - O papel dos sistemas fluviais amazônicos no balanço regional e global de carbono: evasão de CO2 e interações entre os ambientes terrestres e aquáticos
Beneficiário:Reynaldo Luiz Victória
Linha de fomento: Auxílio à Pesquisa - Temático