Effects of sunlight on tundra nitrous oxide and methane fluxes in maritime Antarctica
at : Jul 20, 2020 14:45:09  (view:302)

BAO Tao1,2, ZHU Renbin1*, YE Wenjuan1 & XU Hua3

1 Anhui Province Key Laboratory of Polar Environment and Global Change, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230036, China;

2 Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China;

3 State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China

Corresponding author, E-mail: zhurb@ustc.edu.cn

Abstract   The relationships of Nitrous Oxide (N2O) and Methane (CH4) emissions have been extensive studied in Antarctic terrestrial ecosystems. However, impacts of sunlight on soil N2O and CH4 fluxes are highly neglected across Antarctica tundra. Here, fluxes of N2O and CH4 from maritime Antarctic tundra were measured in the absence and presence of sunlight over the three-year summers. The N2O fluxes averaged −4.6±1.2 μg·m−2·h−1 in the absence of sunlight and 5.7±1.5 μg·m−2·h−1 in the presence of sunlight, respectively. The CH4 fluxes averaged 119.8±24.5 μg·m−2·h−1 in the absence of sunlight and −40.5±28.3 μg·m−2·h−1 in the presence of sunlight, respectively. The correlation between N2O, CH4 fluxes and other environmental variables (e.g. soil moisture, temperature, organic and inorganic matters) were not statistically significant (P>0.05) at all sites. Sunlight significantly increased N2O emission and CH4 uptake by mean 10.3 μg·m−2·h−1 and 160.3 μg·m−2·h−1, respectively. Considering sunlight is critical for accurately estimating N2O and CH4 budgets from maritime Antarctica, and necessary for constraining the role of tundra emissions.

Keywords: response, dark, greenhouse gas, wetland, Antarctica