TRACE GAS EMISSIONS FROM A NORTH WALES FEN - ROLE OF HYDROCHEMISTRY AND SOIL ENZYME-ACTIVITY

Fluxes of methane and nitrous oxide from a wetland were compared to hy drochemistry (NO3- and SO42-) and soil enzyme activities (beta-glucosi dase) in an attempt to predict gas fluxes using chemical and enzymatic activities in north Wales, UK. In a one-year survey, the enzyme activ ities ranged from 0.028 to 0.065 mu mol g(-1) min(-1), while NO3- and SO42- concentrations ranged between 0-0.78 and 5-200 mg L-1, respectiv ely. Methane and nitrous oxide emissions varied between 0.32-240 and 0 .28-5.48 mg m(-1) da(-1), respectively. The field survey was followed by laboratory-based manipulation experiments, from which pilot mathema tical models were constructed, and related to the field data. The vari ation of methane emission was attributed to changes in SO42- concentra tion and temperature at the site. In contrast, NO3- concentration, wat er table height, and beta-glucosidase activity were major controlling factors for nitrous oxide emission. The models explained more than 80 % of the variation observed in the field study.