ENZYMES AND BIOGEOCHEMICAL CYCLING IN WETLANDS DURING A SIMULATED DROUGHT

Possible interactions between soil enzymes and the biogeochemistry of wetlands were investigated during a field-based drought simulation. Un der control (waterlogged) conditions, correlations were found between the activity of the enzyme B-glucosidase and two properties associated with carbon cycling, namely i) CH4 release (r = 0.79, p < 0.01) and ) dissolved organic carbon concentration (r = -0.81, p < 0.01). In contr ast, the transition to drought conditions resulted in correlations bet ween a-glucosidase activity and certain mineralisation processes, name ly the release of mg and Ca (r = 0.72, p < 0.05). Sulphatase activity correlated with changes in sulphate concentration during the drought s imulation (r = 0.73, p < 0.05). Further support for the suggested enzy mic involvement in biogeochemical processes was found in laboratory st udies. These experiments indicated that increasing the abundance of B- glucosidase could stimulate trace gas emissions (p < 0.001) and increa se the concentration of magnesium and calcium (p < 0.05). Increased su lphatase abundance caused a suppression of methane emissions (p = 0.05 3).