Marked isotopic variability within and between the Amazon River and marine dissolved black carbon pools

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Coppola, Alysha I. ^[1] ; Seidel, Michael ^[2] ; Ward, Nicholas D. ^{[3, 4]} ; Viviroli, Daniel ^[1] ; Nascimento, Gabriela S. ^{[1, 5]} ; Haghipour, Negar ^{[5, 6]} ; Revels, Brandi N. ^[5] ; Abiven, Samuel ^[1] ; Jones, Matthew W. ^[7] ; Richey, Jeffrey E. ^[4] ; Eglinton, Timothy I. ^[5] ; Dittmar, Thorsten ^{[2, 8]} ; Schmidt, Michael W. I. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Zurich, Dept Geog, Winterthurerstr 190, CH-8057 Zurich - Switzerland

^[2] Carl von Ossietzky Univ Oldenburg, Res Grp Marine Geochem, Inst Chem & Biol Marine Environm ICBM, D-26129 Oldenburg - Germany

^[3] Pacific Northwest Natl Lab, Marine Sci Lab, 1529 West Sequim Bay Rd, Sequim, WA 98382 - USA

^[4] Univ Washington, Sch Oceanog, Box 355351, Seattle, WA 98195 - USA

^[5] Swiss Fed Inst Technol, Inst Geol, Dept Earth Sci, Sonneggstr 5, CH-8092 Zurich - Switzerland

^[6] Swiss Fed Inst Technol, Lab Ion Beam Phys, Otto Stern Weg 5, CH-8093 Zurich - Switzerland

^[7] Univ East Anglia, Tyndall Ctr Climate Change Res, Sch Environm Sci, Norwich NR4 7TJ, Norfolk - England

^[8] Univ Oldenburg HIFMB, Helmholtz Inst Funct Marine Biodivers, Ammerlander Heerstr 231, D-26129 Oldenburg - Germany

• Tipo de documento: Artigo Científico
• Fonte: NATURE COMMUNICATIONS; v. 10, SEP 5 2019.
• Citações Web of Science: 1

Resumo

Riverine dissolved organic carbon (DOC) contains charcoal byproducts, termed black carbon (BC). To determine the significance of BC as a sink of atmospheric CO2 and reconcile budgets, the sources and fate of this large, slow-cycling and elusive carbon pool must be constrained. The Amazon River is a significant part of global BC cycling because it exports an order of magnitude more DOC, and thus dissolved BC (DBC), than any other river. We report spatially resolved DBC quantity and radiocarbon (Delta(14)c) measurements, paired with molecular-level characterization of dissolved organic matter from the Amazon River and tributaries during low discharge. The proportion of BC-like polycyclic aromatic structures decreases downstream, but marked spatial variability in abundance and Delta C-14 values of DBC molecular markers imply dynamic sources and cycling in a manner that is incongruent with bulk DOC. We estimate a flux from the Amazon River of 1.9-2.7 Tg DBC yr(-1) that is composed of predominately young DBC, suggesting that loss processes of modern DBC are important. (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