Summer CO2 evasion from streams and rivers in the Kolyma River basin, north-east Siberia

Abstract

Inland water systems are generally supersaturated in carbon dioxide (CO₂) and are increasingly recognized as playing an important role in the global carbon cycle. The Arctic may be particularly important in this respect, given the abundance of inland waters and carbon contained in Arctic soils; however, a lack of trace gas measurements from small streams in the Arctic currently limits this understanding.We investigated the spatial variability of CO₂ evasion during the summer low-flow period from streams and rivers in the northern portion of the Kolyma River basin in north-eastern Siberia. To this end, partial pressure of carbon dioxide (pCO₂) and gas exchange velocities (k) were measured at a diverse set of streams and rivers to calculate CO₂ evasion fluxes. We combined these CO2 evasion estimates with satellite remote sensing and geographic information system techniques to calculate total areal CO₂ emissions. Our results show that small streams are substantial sources of atmospheric CO₂ owing to high pCO₂ and k, despite being a small portion of total inland water surface area. In contrast, large rivers were generally near equilibrium with atmospheric CO₂. Extrapolating our findings across the Panteleikha-Ambolikha sub-watersheds demonstrated that small streams play a major role in CO₂ evasion, accounting for 86% of the total summer CO₂ emissions from inland waters within these two sub-watersheds. Further expansion of these regional CO₂ emission estimates across time and space will be critical to accurately quantify and understand the role of Arctic streams and rivers in the global carbon budget.

Keywords: Arctic streams and rivers; CO₂ evasion; inland water surface area; Kolyma River; pCO₂; Siberia

(Published: 5 December 2013)

Citation: Polar Research 2013, 32, 19704, http://dx.doi.org/10.3402/polar.v32i0.19704