Degradation legacy and current water levels as predictors of carbon emissions from two fen sites

Mires and Peat

Willem-Jan Emsens¹  Peter Shenk¹  Martijn van Roie¹  Rudy van Diggelen¹  Yvonne Liczner¹  Erik Verbruggen² 

[1] Ecosystem Management Research Group, Department of Biology, University of Antwerp, Wilrijk, Belgium;Plants and Ecosystems Research Group, Department of Biology, University of Antwerp, Wilrijk, Belgium;

关键词: carbon dioxide;    climate change;    methane;    peatlands;    rewetting;   

DOI  :  10.19189/MaP.2020.SNPG.StA.2149

来源: DOAJ

【 摘 要 】

Drainage-induced shifts in physicochemical peat properties are irreversible on a decadal time span. We investigated whether carbon emissions from fen peat can be estimated using two proxies: current water levels and peat properties (as affected by drainage history, i.e. degradation legacy). We collected bare peat monoliths from a long-term drained and an undrained fen. In a crossed design, half of the monoliths was kept wet and the other half was drained. Highest carbon dioxide (CO2) emissions came from the originally undrained peat under low water levels (607 mmol m-2 d-1). Overall, CO2 emissions were primarily determined by drainage history, with 141 % higher emissions from the originally undrained peat. In addition, low current water levels correlated with 42 % higher emissions. Highest methane (CH4) emissions were measured in the originally undrained peat under high water levels (123 mmol m-2 d-1). Overall, CH4 emissions were primarily determined by current water levels, with 430 % higher emissions under high water levels. In addition, the originally undrained peat had 180 % higher emissions. The lower C efflux from originally drained peat correlated with lower concentrations of methanogens and of easily-degradable carbon substrate (cellulose). We conclude that substrate limitation in long-term drained fens ensures low baseline carbon emissions, which provides opportunities for renewed carbon sequestration by rewetting.

【 授权许可】

Unknown