Nitrous Oxide Emission from <Emphasis Type="Italic">Deyeuxia angustifolia</Emphasis> Freshwater Marsh in Northeast China |
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Authors: | Junbao Yu Jingshuang Liu Jinda Wang Weidong Sun Jr" target="_blank">William H PatrickJr Franz X Meixner |
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Institution: | (1) Key Lab of Wetland Ecology and Environment, Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences, 3195 Weishan Road, Changchun, 130012, China;(2) Key Lab of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Wushan, P.O. Box 1131, Guangzhou, 510640, China;(3) Wetland Biogeochemistry Institute, Louisiana State University, Baton Rouge, LA 70803, USA;(4) Biogeochemistry Department, Max Planck Institute for Chemistry, P.O. Box 3060, D-55020 Mainz, Germany |
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Abstract: | Here we report N2O emission results for freshwater marshes isolated from human activities at the Sanjiang Experimental Station of Marsh Wetland
Ecology in northeastern China. These results are important for us to understand N2O emission in natural processes in undisturbed freshwater marsh. Two adjacent plots of Deyeuxia angustifolia freshwater marsh with different water regimes, i.e., seasonally waterlogged (SW) and not- waterlogged (NW), were chosen for
gas sampling, and soil and biomass studies. Emissions of N2O from NW plots were obviously higher than from the SW plots. Daily maximum N2O flux was observed at 13 o′clock and the seasonal maximum occurred in end July to early August. The annual average N2O emissions from the NW marsh were 4.45 μg m−2 h−1 in 2002 and 6.85 μg m−2 h−1 in 2003 during growing season. The SW marsh was overall a sink for N2O with corresponding annual emissions of −1.00 μg m−2 h−1 for 2002 and −0.76 μg m−2 h−1 for 2003. There were significant correlations between N2O fluxes and temperatures of both air and 5-cm-depth soil. The range of soil redox potential 200–400 mV appeared to be optimum
for N2O flux. Besides temperature and plant biomass, the freeze–thaw process is also an important factor for N2O emission burst. Our results show that the freshwater marsh isolated from human activity in northeastern China is not a major
source of N2O. |
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Keywords: | Nitrous oxide Freshwater marsh Impact factors Diurnal and seasonal variations Freeze– thaw region |
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