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 i n a wet meadow vegetation manipulation site at the Toolik Lake Long-Te rm Ecological Research (LTER) site during the summers of 1995 and 1996 . Control plots, moss-removal plots, and sedge-removal plots were stud ied to determine the role of these vegetation types in wetland methane emission and to study the gas transport mechanism. Methane emission w as greatest from plots with intact sedges. Depth distributions of root density collected in 1995 showed a strong inverse relationship to por e water methane concentration. Results on insertion of arrays of gas-p ermeable silicone rubber tubing into the soil indicate that they are r easonable analogs for the physical process of gaseous diffusion throug h plants. The observed differences in flux between plots with and with out sedges cannot be fully explained by differences in methane product ion or dissolved organic carbon concentrations in our measurements.