Trace Gas Emissions from a North Wales Fen — Role of Hydrochemistry and Soil Enzyme Activity

Abstract

Fluxes of methane and nitrous oxide from a wetland were compared to hydrochemistry (NO ⁻₃ and SO ²⁻₄ ) 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 NO ⁻₃ and SO ²⁻₄ 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 SO ²⁻₄ concentration and temperature at the site. In contrast, NO ⁻₃ 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.