Enzyme activities

Extracellular enzymes, originating primarily from microorganisms and the roots of plants, play a pivotal role in wetland biogeochemistry by driving organic matter transformations. For example, in wetlands, extracellular enzyme activities have been considered in relation to nutrient availability, efficiency of wastewater treatment, decomposition of soil organic matter, and trace gas emission. The effects of environmental conditions on enzyme activities have also drawn much attention. For example, the impacts of water level drawdown, elevated CO2, O3, ultraviolet radiation, temperature change, land use change, and heavy metals have all been addressed. In this chapter, a method for the measurement of extracellular enzyme activity through the use of fluorogenic model substrates is described. Methylumbelliferyl substrates are prepared and added to wetland soils, and the fluorescence produced is quantified and presented as enzyme activity. This method is highly sensitive, with high reproducibility, and hence represents a particularly effective measure of extracellular enzyme activities in wetlands.