Oxidative mitigation of aquatic methane emissions in large Amazonian rivers

Autor(es)

Sawakuchi, Henrique O. ^[1] ; Bastviken, David ^[2] ; Sawakuchi, Andre O. ^[3] ; Ward, Nicholas D. ^[4] ; Borges, Clovis D. ^[1] ; Tsai, Siu M. ^[1] ; Richey, Jeffrey E. ^[5] ; Ballester, Maria Victoria R. ^[1] ; Krusche, Alex V. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Ctr Nucl Energy Agr, Ave Centenario 303, BR-13400970 Piracicaba, SP - Brazil

^[2] Linkoping Univ, Dept Themat Studies Environm Change, SE-58183 Linkoping - Sweden

^[3] Univ Sao Paulo, Inst Geosci, Dept Sedimentary & Environm Geol, Rua Lago 562, BR-05508080 Sao Paulo, SP - Brazil

^[4] Univ Florida, Dept Geol Sci, Box 112120, Gainesville, FL 32611 - USA

^[5] Univ Washington, Sch Oceanog, Seattle, WA 98195 - USA

• Tipo de documento: Artigo Científico
• Fonte: GLOBAL CHANGE BIOLOGY; v. 22, n. 3, p. 1075-1085, MAR 2016.
• Citações Web of Science: 18

Resumo

The flux of methane (CH4) from inland waters to the atmosphere has a profound impact on global atmospheric greenhouse gas (GHG) levels, and yet, strikingly little is known about the dynamics controlling sources and sinks of CH4 in the aquatic setting. Here, we examine the cycling and flux of CH4 in six large rivers in the Amazon basin, including the Amazon River. Based on stable isotopic mass balances of CH4, inputs and outputs to the water column were estimated. We determined that ecosystem methane oxidation (MOX) reduced the diffusive flux of CH4 by approximately 28-96% and varied depending on hydrologic regime and general geochemical characteristics of tributaries of the Amazon River. For example, the relative amount of MOX was maximal during high water in black and white water rivers and minimal in clear water rivers during low water. The abundance of genetic markers for methane-oxidizing bacteria (pmoA) was positively correlated with enhanced signals of oxidation, providing independent support for the detected MOX patterns. The results indicate that MOX in large Amazonian rivers can consume from 0.45 to 2.07 Tg CH4 yr(-1), representing up to 7% of the estimated global soil sink. Nevertheless, climate change and changes in hydrology, for example, due to construction of dams, can alter this balance, influencing CH4 emissions to atmosphere. (AU)

• Processo FAPESP: 08/58089-9 - The role of rivers on the regional carbon cycle
• Beneficiário: Maria Victoria Ramos Ballester
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático
• Processo FAPESP: 11/14502-2 - Fatores reguladores da emissão de metano (CH4) em ambientes deposicionais dos Rios Negro, Tapajós, Xingu e Amazonas
• Beneficiário: Henrique Oliveira Sawakuchi
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 12/17359-9 - Fluxo de metano de rios e os diferentes métodos para estimar a produção e oxidação de metano de ecossistemas aquáticos continentais
• Beneficiário: Henrique Oliveira Sawakuchi
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
• Processo FAPESP: 11/06609-1 - Proveniência, transporte e estocagem de sedimentos nos rios amazônicos
• Beneficiário: André Oliveira Sawakuchi
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 08/58114-3 - Monitoring the microbial diversity and functional activities in response to land-use changes and deforestation under soybean and sugarcane cultivations
• Beneficiário: Tsai Siu Mui
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático