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EAFES Symposium ES11-3

Effect of Water Table Lowering and Nitrogen deposition on GHGs Fluxes in an Alpine Wetland Ecosystem of the Tibetan Plateau

HE Jinsheng (Peking Univ)

Lingfei Yu, Jin-Sheng He

College of Urban and Environmental Sciences, Peking University

Water table lowering and N deposition are expected to alter carbon cycle in wetlands and thus have significant feedback on the climate change. We investigated GHGs fluxes response to water table lowering and N addition in a controlled experiment with peat monoliths cored from an alpine wetland since July 2011 at the Haibei Alpine Grassland Ecosystem Research Station (latitude 37.61°N, longitude 101.31˚E, and altitude 3203 m asl), Chinese Academy of Sciences. CO2 and CH4 fluxes were measured approximately once a week over the growing season of 2011 using the static chamber/gas chromatography method.

Water table lowering significantly reduced CO2 sequestration and CH4 emission by 25.2% and 74.5%. Nitrogen addition only marginally increased CO2 sequestration and did not have significantly influence on CH4 emission. When integrated greenhouse effect was taken into account, both water table lowering and nitrogen addition increased equivalently CO2 sequestration by 104.16% and 62.91%, respectively. Therefore, in the growing season, water table lowering and nitrogen addition reduced the greenhouse effect in the alpine wetland of the Tibetan Plateau. The reduction was attributed to a substantial decrease in CH4 emissions when water table was lowered.


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