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 hydrochemistry (NO₃^- and SO₄/^2-) and soil enzyme activities (β- glucosidase) in an attempt to predict gas fluxes using chemical and enzymatic activities in north Wales, UK. In a one-year survey, the enzyme activities ranged from 0.028 to 0.065 μmol g^-1 min^-1, while NO₃^- and SO₄^2- concentrations ranged between 0-0.78 and 5-200 mg L^-1, respectively. 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 mathematical models were constructed, and related to the field data. The variation of methane emission was attributed to changes in SO₄/^2- concentration and temperature at the site. In contrast, NO₃^- concentration, water table height, and β- glucosidase activity were major controlling factors for nitrous oxide emission. The models explained more than 80 % of the variation observed in the field study.