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

Authors :
Coppola AI
Seidel M
Ward ND
Viviroli D
Nascimento GS
Haghipour N
Revels BN
Abiven S
Jones MW
Richey JE
Eglinton TI
Dittmar T
Schmidt MWI
Source :
Nature communications [Nat Commun] 2019 Sep 05; Vol. 10 (1), pp. 4018. Date of Electronic Publication: 2019 Sep 05.
Publication Year :
2019

Abstract

Riverine dissolved organic carbon (DOC) contains charcoal byproducts, termed black carbon (BC). To determine the significance of BC as a sink of atmospheric CO <subscript>2</subscript> 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 (Δ <superscript>14</superscript> 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 Δ <superscript>14</superscript> C 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 <superscript>-1</superscript> that is composed of predominately young DBC, suggesting that loss processes of modern DBC are important.

Details

Language :
English
ISSN :
2041-1723
Volume :
10
Issue :
1
Database :
MEDLINE
Journal :
Nature communications
Publication Type :
Academic Journal
Accession number :
31488815
Full Text :
https://doi.org/10.1038/s41467-019-11543-9