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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.)

Physical controls on carbon dioxide transfer velocity and flux in low-gradient river systems and implications for regional carbon budgets

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Autor(es):
Alin, Simone R. [1] ; Rasera, Maria de Fatima F. L. [2] ; Salimon, Cleber I. [3] ; Richey, Jeffrey E. [1] ; Holtgrieve, Gordon W. [4] ; Krusche, Alex V. [2] ; Snidvongs, Anond [5]
Número total de Autores: 7
Afiliação do(s) autor(es):
[1] Univ Washington, Sch Oceanog, Seattle, WA 98195 - USA
[2] Univ Sao Paulo, Ctr Energia Nucl Agr, BR-13400970 Piracicaba, SP - Brazil
[3] Univ Fed Acre, BR-69915900 Rio Branco, AC - Brazil
[4] Univ Washington, Sch Aquat & Fishery Sci, Seattle, WA 98195 - USA
[5] Chulalongkorn Univ, SE Asia START Global Change Reg Ctr, Bangkok 10330 - Thailand
Número total de Afiliações: 5
Tipo de documento: Artigo Científico
Fonte: JOURNAL OF GEOPHYSICAL RESEARCH; v. 116, JAN 27 2011.
Citações Web of Science: 103
Resumo

Outgassing of carbon dioxide (CO(2)) from rivers and streams to the atmosphere is a major loss term in the coupled terrestrial-aquatic carbon cycle of major low-gradient river systems (the term ``river system{''} encompasses the rivers and streams of all sizes that compose the drainage network in a river basin). However, the magnitude and controls on this important carbon flux are not well quantified. We measured carbon dioxide flux rates (F(CO2)), gas transfer velocity (k), and partial pressures (p(CO2)) in rivers and streams of the Amazon and Mekong river systems in South America and Southeast Asia, respectively. F(CO2) and k values were significantly higher in small rivers and streams (channels <100 m wide) than in large rivers (channels >100 m wide). Small rivers and streams also had substantially higher variability in k values than large rivers. Observed F(CO2) and k values suggest that previous estimates of basinwide CO(2) evasion from tropical rivers and wetlands have been conservative and are likely to be revised upward substantially in the future. Data from the present study combined with data compiled from the literature collectively suggest that the physical control of gas exchange velocities and fluxes in low-gradient river systems makes a transition from the dominance of wind control at the largest spatial scales (in estuaries and river mainstems) toward increasing importance of water current velocity and depth at progressively smaller channel dimensions upstream. These results highlight the importance of incorporating scale-appropriate k values into basinwide models of whole ecosystem carbon balance. (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
Processo FAPESP: 03/07778-5 - Fluxos de carbono em ambientes fluviais e suas origens na Amazônia Ocidental
Beneficiário:Cleber Ibraim Salimon
Linha de fomento: Bolsas no Brasil - Pós-Doutorado