A weak C sink at high latitudes: support from an integrated terrestrial – aquatic C balance

Monday, 15 December 2014: 5:45 PM
Erik J Lundin1,2, Torben R Christensen3, Reiner Giesler2, Michal Heliasz3, Jonatan Klaminder2, Andreas Persson4 and Jan Karlsson2, (1)Stockholm University, Stockholm, Sweden, (2)Umeå University, Umeå, Sweden, (3)Lund University, Physical Geography and Ecosystem Sciences, Lund, Sweden, (4)Lund University, Lund, Sweden
High latitude ecosystems have served as net sinks of atmospheric carbon (C) in a Holocene time perspective. However, the ongoing warming makes it questionable if high latitude landscapes still function as net C sinks. In this study we used multiyear high resolution C flux data to estimate an integrated terrestrial-aquatic C balance of a sub-arctic catchment. The results indicate large inter annual variability in C fluxes and suggest that the C sink function of this landscape is weak, especially when also accounting for the often neglected C losses from aquatic systems. In fact, our results suggest that it is more likely that the studied catchment serves as a net source of C rather than a net sink. Our results highlight the importance of inland waters in the C cycle and that the strength of the C sequestering in the contemporary sub-arctic environment is much weaker than often assumed.