Carbon dioxide and methane emissions from the Yukon River system

Global Biogeochemical Cycles
By: , and 



Carbon dioxide (CO2) and methane (CH4) emissions are important, but poorly quantified, components of riverine carbon (C) budgets. This is largely because the data needed for gas flux calculations are sparse and are spatially and temporally variable. Additionally, the importance of C gas emissions relative to lateral C exports is not well known because gaseous and aqueous fluxes are not commonly measured on the same rivers. We couple measurements of aqueous CO2 and CH4 partial pressures (pCO2, pCH4) and flux across the water-air interface with gas transfer models to calculate subbasin distributions of gas flux density. We then combine those flux densities with remote and direct observations of stream and river water surface area and ice duration, to calculate C gas emissions from flowing waters throughout the Yukon River basin. CO2emissions were 7.68 Tg C yr−1 (95% CI: 5.84 −10.46), averaging 750 g C m−2 yr−1 normalized to water surface area, and 9.0 g C m−2 yr−1 normalized to river basin area. River CH4 emissions totaled 55 Gg C yr−1 or 0.7% of the total mass of C emitted as CO2 plus CH4 and ∼6.4% of their combined radiative forcing. When combined with lateral inorganic plus organic C exports to below head of tide, C gas emissions comprised 50% of total C exported by the Yukon River and its tributaries. River CO2 and CH4 derive from multiple sources, including groundwater, surface water runoff, carbonate equilibrium reactions, and benthic and water column microbial processing of organic C. The exact role of each of these processes is not yet quantified in the overall river C budget.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Carbon dioxide and methane emissions from the Yukon River system
Series title Global Biogeochemical Cycles
DOI 10.1029/2012GB004306
Volume 26
Issue 4
Year Published 2012
Language English
Publisher AGU
Contributing office(s) Earth Resources Observation and Science (EROS) Center, National Research Program - Central Branch
Description GB0E05: 11 p.
Country Canada, United States
Other Geospatial Yukon River Basin
Online Only (Y/N) N
Additional Online Files (Y/N) N
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