Scaling down the analysis of environmental processes: monitoring enzyme activity in natural substrates on a millimeter resolution scale.

Natural environments often show high levels of spatial heterogeneity. With a methodology based on the immobilization of fluorescent substrates, the distribution of extracellular enzymes can be studied at a 2.3-mm resolution with a detection limit of 1.8 nmol · h(-1) · cm(-2). The method is applicable to environmental samples such as wood, litter, soil, or fungal colonies.