Methane release from the southern Brazilian margin during the last glacial

Autor(es):Mostrar menos -

Portilho-Ramos, R. C. ^{[1, 2, 3]} ; Cruz, A. P. S. ^[3] ; Barbosa, C. F. ^[3] ; Rathburn, A. E. ^[4] ; Mulitza, S. ^[2] ; Venancio, I. M. ^[5] ; Schwenk, T. ^[2] ; Ruehlemann, C. ^[6] ; Vidal, L. ^[7] ; Chiessi, C. M. ^[8] ; Silveira, C. S. ^[3]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Geosci, Rua Lago 562, BR-05508080 Sao Paulo, SP - Brazil

^[2] Univ Bremen, MARUM Ctr Marine Environm Sci, Leobener Str, D-28359 Bremen - Germany

^[3] Univ Fed Fluminense, Programa Posgrad Geoquim, Outeiro Sao Joao Batista S-N, BR-24020141 Niteroi, RJ - Brazil

^[4] Calif State Univ Bakersfield, Dept Geol Sci, 9001 Stockdale Highway, Bakersfield, CA - USA

^[5] Natl Inst Space Res INPE, Ctr Weather Forecasting & Climate Studies CPTEC, Cachoeira Paulista - Brazil

^[6] BGR Fed Inst Geosci & Nat Resources, Stilleweg 2, D-30655 Hannover - Germany

^[7] Aix Marseille Univ, CNRS, IRD, CEREGE UM34, F-13545 Aix En Provence - France

^[8] Univ Sao Paulo, Sch Arts Sci & Humanities, Ave Arlindo Bettio 1000, BR-03828000 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: SCIENTIFIC REPORTS; v. 8, APR 13 2018.
• Citações Web of Science: 10

Resumo

Seafloor methane release can significantly affect the global carbon cycle and climate. Appreciable quantities of methane are stored in continental margin sediments as shallow gas and hydrate deposits, and changes in pressure, temperature and/or bottom-currents can liberate significant amounts of this greenhouse gas. Understanding the spatial and temporal dynamics of marine methane deposits and their relationships to environmental change are critical for assessing past and future carbon cycle and climate change. Here we present foraminiferal stable carbon isotope and sediment mineralogy records suggesting for the first time that seafloor methane release occurred along the southern Brazilian margin during the last glacial period (40-20 cal ka BP). Our results show that shallow gas deposits on the southern Brazilian margin responded to glacial-interglacial paleoceanographic changes releasing methane due to the synergy of sea level lowstand, warmer bottom waters and vigorous bottom currents during the last glacial period. High sea level during the Holocene resulted in an upslope shift of the Brazil Current, cooling the bottom waters and reducing bottom current strength, reducing methane emissions from the southern Brazilian margin. (AU)

• Processo FAPESP: 12/17517-3 - Resposta da porção oeste do Oceano Atlântico às mudanças na circulação meridional do Atlântico: variabilidade milenar a sazonal
• Beneficiário: Cristiano Mazur Chiessi
• Linha de fomento: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Jovens Pesquisadores