Methane emissions from two tundra wetlands in eastern Antarctica: Fid-Bau Portal

Methane emissions from two tundra wetlands in eastern Antarctica

Zhu, Renbin / Liu, Yashu / Sun, Liguang / Xu, Hua

AbstractDuring the summertime of 2005/2006 net methane $({CH}_{4})$ fluxes and environmental variables were investigated in two tundra wetlands Wolong Marsh and Tuanjie Marsh of eastern Antarctica, using the closed chamber technique. At Wolong Marsh, the measurements were made at four wet tundra sites, four mesic tundra sites, and two dry sites. ${CH}_{4}$ flux for wet tundra sites averaged $163.4 μ g m^{- 2} h^{- 1}$ and for the mesic sites $132.4 μ g m^{- 2} h^{- 1}$ . For the dry sites, all the ${CH}_{4}$ fluxes showed the negative values with an average of $- 99.9 μ g m^{- 2} h^{- 1}$ . At Tuanjie Marsh, flux measurements were made at two open ponds, two shallow fens and two dry sites. The average ${CH}_{4}$ flux for the pond sites was $170.4 μ g m^{- 2} h^{- 1}$ and for the fen sites $134.7 μ g m^{- 2} h^{- 1}$ . For the dry sites ${CH}_{4}$ fluxes were approximately one order of magnitude lower than those for pond and fen sites and averaged $18.4 μ g m^{- 2} h^{- 1}$ . Spatial variations in ${CH}_{4}$ flux were primarily driven by the water table position at two tundra wetlands, whereas temporal variations in ${CH}_{4}$ flux from wet and mesic sites were related with the thermal regime of tundra soil layers. The fluxes from six observation sites showed a consistent diurnal cycle with the peak at 14:00 and the lowest at 2:00 (local time), which was correlated with ground temperature at the depth of 0–10cm. The ${CH}_{4}$ emissions from coastal wetlands could constitute an important part of the annual ${CH}_{4}$ budget for Antarctic tundra ecosystems.