In most streams, community production is sustained by the decomposition of imported plant litter. The early stages of plant litter decomposition have received much study; but little work has focused on the fate of fine organic particles (FPOM), the form in which most particulate detritus moves through stream ecosystems. Utilizing recently developed biochemical techniques, I propose to investigate the structure and activity of FPOM- associated microbial communities in two concurrent field experiments. The first is intended to evaluate a series of basic hypotheses about microbial production, extracellular enzyme activity and community structure over a broad range of conditions. The second is focused specifically on the relationship between FPOM degradation rates and the activity of lignocellulose-degrading enzymes. %%% This work will contribute to our basic understanding of the operation of attached microbial communities, a topic of broad interest. In addition, it may lead to the formulation of models that relate FPOM mass loss, currently difficult to determine in situ, to the activity of lignocellulose-degrading enzymes, a readily quantified measure. Such a model would permit routine monitoring of FPOM degradation rates, an application that could contribute to future studies of ecosystem processes and management.
