This research evaluates how attached aquatic microflora (periphyton) regulate (1) the rates of deposition of organic carbon that is imported from upland areas or synthesized by aquatic plants and algae in these regions , and (2) the retention or loss rates of organic carbon. The microbiota accomplish this regulation by a combination of intensive decomposition of dissolved organic carbon to CO2 and methane and by burying a significant portion of microbial biomass that does not decompose. High metabolism and growth results from intensive recycling of nutrients within the communities. The research program will examine natural communities under replicated experimental conditions for: (1) Metabolic and community carbon retention and decomposition to CO2 and methane in response to substratum. (2) Resistance to nutrient limitations of phosphorus and nitrogen and the effects on carbon losses. (3) Effects of different types of dissolved organic compounds on metabolic recycling and carbon losses. (4) Determination of lateral microscale fluxes of nutrients within these attached communities. %%% Wetland/ littoral and floodplain land-water interface regions of lake and river ecosystems are being recognized as major depositional areas for organic carbon. Organic carbon storage versus evolution of metabolized carbon in the form of CO2 and methane is important because these 'greenhouse' gases are critical to global climate change evaluations. ***//
