Geography
Document Type
Article
Abstract
While much of the dissolved organic carbon (DOC) within rivers is destined for mineralization to CO2, a substantial fraction of riverine bicarbonate (HCO3-) flux represents a CO2 sink, as a result of weathering processes that sequester CO2 as HCO 3-. We explored landscape-level controls on DOC and HCO3- flux in subcatchments of the boreal, with a specific focus on the effect of permafrost on riverine dissolved C flux. To do this, we undertook a multivariate analysis that partitioned the variance attributable to known, key regulators of dissolved C flux (runoff, lithology, and vegetation) prior to examining the effect of permafrost, using riverine biogeochemistry data from a suite of subcatchments drawn from the Mackenzie, Yukon, East, and West Siberian regions of the circumboreal. Across the diverse catchments that we study, controls on HCO3- flux were near-universal: runoff and an increased carbonate rock contribution to weathering (assessed as riverwater Ca:Na) increased HCO3- yields, while increasing permafrost extent was associated with decreases in HCO3-. In contrast, permafrost had contrasting and region-specific effects on DOC yield, even after the variation caused by other key drivers of its flux had been accounted for. We used ionic ratios and SO4 yields to calculate the potential range of CO2 sequestered via weathering across these boreal subcatchments, and show that decreasing permafrost extent is associated with increases in weathering-mediated CO2 fixation across broad spatial scales, an effect that could counterbalance some of the organic C mineralization that is predicted with declining permafrost. © 2012. American Geophysical Union. All Rights Reserved.
Publication Title
Global Biogeochemical Cycles
Publication Date
2012
Volume
26
Issue
3
ISSN
0886-6236
DOI
10.1029/2012GB004299
Keywords
bicarbonate, biogeochemistry, Boreal Kingdom, carbon dioxide, carbon fixation, carbon flux, carbon sequestration, carbon sink, catchment, chemical weathering, dissolved organic carbon, mineralization, multivariate analysis, permafrost, runoff, spatial analysis, sulfate
Repository Citation
Tank, Suzanne E.; Frey, Karen E.; Striegl, Robert G.; Raymond, Peter A.; Holmes, Robert M.; McClelland, James W.; and Peterson, Bruce J., "Landscape-level controls on dissolved carbon flux from diverse catchments of the circumboreal" (2012). Geography. 230.
https://commons.clarku.edu/faculty_geography/230
Copyright
Published source must be acknowledged with citation: Tank, Suzanne E., et al. "Landscape‐level controls on dissolved carbon flux from diverse catchments of the circumboreal." Global Biogeochemical Cycles 26.4 (2012).