Microbial ecology, of all areas of general ecology, is the least well researched and understood. This is most obvious in aquatic microbial ecology. In recent years, because of genetic engineering of microbes, there is a national need to know more about microbial ecology. Dr. Suberkropp, of the University of Alabama, proposes to study aquatic microbial and invertebrate communities. The proposed studies are designed to determine the degree to which the species composition of fungi colonizing leaves in different stream habitats affects the growth of leaf-shredding habitats. The dynamics of leaf conditioning by the dominant fungi in these steams will be determined to establish the time required by each species to fully condition leaves in the laboratory. The rates of growth, ingestion, egestion and respiration of shredders from different streams fed diets of leaves that have been fully conditioned by pure cultures of these fungi will be used to estimate the food quality of fungal species. Energetics of different shredder taxa fed fungi of high and low food quality will be compared. The effect of fungal species composition on shredder growth will be examined for leaves colonized in streams containing fungal communities dominated by different fungal species. The fungal species present on leaves will be determined, and shredder performance on diets of these leaves will be evaluated. Results will be related to food quality of the fungi colonizing leaves in different streams. The studies proposed will provide a comparative data base on relationships between shredder performance and diets of different fungal species in pure culture and in natural microbial communities and should increase understanding of the range of interactions that can occur between these two groups of organisms.
