Methane emission and transport by Arctic sedges in Alaska: Results of a vegetation removal experiment

Methane flux and below-ground methane profile studies were conducted in a wet meadow vegetation manipulation site at the Toolik Lake Long-Term Ecological Research (LTER) site during the summers of 1995 and 1996. Control plots, moss-removal plots, and sedge-removal plots were studied to determine the role of these vegetation types in wetland methane emission and to study the gas transport mechanism. Methane emission was greatest from plots with intact sedges. Depth distributions of root density collected in 1995 showed a strong inverse relationship to pore water methane concentration. Results on insertion of arrays of gas-permeable silicone rubber tubing into the soil indicate that they are reasonable analogs for the physical process of gaseous diffusion through plants. The observed differences in flux between plots with and without sedges cannot be fully explained by differences in methane production or dissolved organic carbon concentrations in our measurements.