Brown water in the Conwy, Kalimantan and Kyoto: DOC in the carbon balance of managed peatlands

Chris Evans1
1 Bangor, Centre for Ecology and Hydrology

Invited Talk 7 in Controls of dissolved organic matter fluxes in ecosystems

14.07.2014, 10:45-11:15, H19

Natural peatlands provide a long-term carbon sink, but degraded peatlands can become major carbon and greenhouse gas (GHG) sources. While land-atmosphere exchange of CO2 and CH4 generally represents the major component of the peatland GHG balance, dissolved organic carbon (DOC) export via natural or artificial drainage networks provide a significant additional pathway of carbon loss, and potentially of indirect GHG emissions. The significance of these fluxes for total anthropogenic GHG emissions depends on: the magnitude of the flux under natural conditions; the extent to which this flux is modified by anthropogenic pressures; and the proportion of DOC that is ultimately converted to CO2 (or CH4) by downstream processes. Whilst there is now some consensus that observed long-term increases in DOC have primarily been caused by changes in atmospheric deposition, the potential influence of land-management, and in particular peatland drainage, on DOC export is less well constrained. Furthermore, the contribution of peatland DOC export to CO2 emissions, which depends on the reactivity of peat-derived organic matter in downstream ecosystems, remains poorly quantified, despite growing recognition of its importance. This presentation will draw on a number of data sources including field and laboratory experiments, long-term monitoring studies, flux measurements and radiocarbon analysis from the United Kingdom, Europe and Southeast Asia. The presentation will also describe the basis for the inclusion of waterborne carbon in the 2013 IPCC Wetland Supplement.

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last modified 2014-04-08