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WATER RESOURCES RESEARCH, VOL. 43, W02411, doi:10.1029/2006WR005201, 2007

Carbon export and cycling by the Yukon, Tanana, and Porcupine rivers, Alaska, 2001–2005

Robert G. Striegl

U.S. Geological Survey, Denver, Colorado, USA


Mark M. Dornblaser

U.S. Geological Survey, Boulder, Colorado, USA


George R. Aiken

U.S. Geological Survey, Boulder, Colorado, USA


Kimberly P. Wickland

U.S. Geological Survey, Boulder, Colorado, USA


Peter A. Raymond

School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut, USA


Abstract

Loads and yields of dissolved and particulate organic and inorganic carbon (DOC, POC, DIC, PIC) were measured and modeled at three locations on the Yukon River (YR) and on the Tanana and Porcupine rivers (TR, PR) in Alaska during 2001–2005. Total YR carbon export averaged 7.8 Tg C yr−1, 30% as OC and 70% as IC. Total C yields (0.39–1.03 mol C m−2 yr−1) were proportional to water yields (139–356 mm yr−1; r2 = 0.84) at all locations. Summer DOC had an aged component (fraction modern (FM) = 0.94–0.97), except in the permafrost wetland-dominated PR, where DOC was modern. POC had FM = 0.63–0.70. DOC had high concentration, high aromaticity, and high hydrophobic content in spring and low concentration, low aromaticity, and high hydrophilic content in winter. About half of annual DOC export occurred during spring. DIC concentration and isotopic composition were strongly affected by dissolution of suspended carbonates in glacial meltwater during summer.

Received 25 May 2006; accepted 6 November 2006; published 10 February 2007.

Keywords: carbon export; climate change; Yukon River Basin.

Index Terms: 0428 Biogeosciences: Carbon cycling (4806); 1615 Global Change: Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912); 1806 Hydrology: Chemistry of fresh water; 1879 Hydrology: Watershed.


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Citation: Striegl, R. G., M. M. Dornblaser, G. R. Aiken, K. P. Wickland, and P. A. Raymond (2007), Carbon export and cycling by the Yukon, Tanana, and Porcupine rivers, Alaska, 2001–2005, Water Resour. Res., 43, W02411, doi:10.1029/2006WR005201.