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GLOBAL BIOGEOCHEMICAL CYCLES,
VOL. 21,
GB4011,
doi:10.1029/2007GB002934,
2007
Flux and age of dissolved organic carbon exported to the Arctic Ocean: A carbon isotopic study of the five largest arctic
rivers
Peter A. Raymond
Yale School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut, USA
J. W. McClelland
University of Texas at Austin, Port Aransas, Texas, USA
R. M. Holmes
Woods Hole Research Center, Falmouth, Massachusetts, USA
A. V. Zhulidov
South Russian Regional Centre for Preparation and Implementation of International Projects, Rostov-on-Don, Russia
K. Mull
Yale School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut, USA
B. J. Peterson
Marine Biological Laboratory, Woods Hole, Massachusetts, USA
R. G. Striegl
U.S. Geological Survey, Denver, Colorado, USA
G. R. Aiken
U.S. Geological Survey, Boulder, Colorado, USA
T. Y. Gurtovaya
South Russian Regional Centre for Preparation and Implementation of International Projects, Rostov-on-Don, Russia
Abstract
The export and Δ14C-age of dissolved organic carbon (DOC) was determined for the Yenisey, Lena, Ob', Mackenzie, and Yukon rivers for 2004–2005.
Concentrations of DOC elevate significantly with increasing discharge in these rivers, causing approximately 60% of the annual
export to occur during a 2-month period following spring ice breakup. We present a total annual flux from the five rivers
of ∼16 teragrams (Tg), and conservatively estimate that the total input of DOC to the Arctic Ocean is 25–36 Tg, which is ∼5–20%
greater than previous fluxes. These fluxes are also ∼2.5× greater than temperate rivers with similar watershed sizes and water
discharge. Δ14C-DOC shows a clear relationship with hydrology. A small pool of DOC slightly depleted in Δ14C is exported with base flow. The large pool exported with spring thaw is enriched in Δ14C with respect to current-day atmospheric Δ14C-CO2 values. A simple model predicts that ∼50% of DOC exported during the arctic spring thaw is 1–5 years old, ∼25% is 6–10 years
in age, and 15% is 11–20 years old. The dominant spring melt period, a historically undersampled period, exports a large amount
of young and presumably semilabile DOC to the Arctic Ocean.
Received 17
January
2007;
accepted 6
July
2007;
published 2
November
2007.
Keywords: DOC;
Arctic;
river.
Index Terms: 0414 Biogeosciences: Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912); 0428 Biogeosciences: Carbon cycling (4806); 0454 Biogeosciences: Isotopic composition and chemistry (1041, 4870); 1030 Geochemistry: Geochemical cycles (0330).
Read Full Article (file size: 487044 bytes) Cited by
Citation: Raymond, P. A., J. W. McClelland, R. M. Holmes, A. V. Zhulidov, K. Mull, B. J. Peterson, R. G. Striegl, G. R. Aiken, and T. Y. Gurtovaya
(2007),
Flux and age of dissolved organic carbon exported to the Arctic Ocean: A carbon isotopic study of the five largest arctic
rivers,
Global Biogeochem. Cycles,
21,
GB4011,
doi:10.1029/2007GB002934.
Copyright 2007 by the American Geophysical Union.
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