The dynamics of dissolved organic carbon (DOC), thought to be a key component of the energy budget of stream ecosystems, will be investigated in streams draining deciduous forest ecosystems of the northeastern United States. The major goal of this research is to develop a state-of-the-art synthesis of carbon cycling in these stream ecosystems, with an emphasis on DOC and microbial processes. Results from previous NSF-funded research will provide most of the data needed to complete the synthesis. New field and laboratory research will be conducted to supply data that is essential to the synthesis effort, but is unavailable either in the existing data sets developed by Dr. Bott and his colleagues, or in the literature. For the past eight years Dr. Bott's research group has studied carbon cycling in streams draining hardwood forests in Pennsylvania. They have conducted many pioneering processes studies on carbon cycling in these streams. In this new research they will synthesize information from previous studies and interpret it in the context of ecosystem disturbance. The data- synthesis effort will culminate in a detailed conceptual model of the structure and function of streams of the northeast and an in- depth analysis of how these streams respond to, and recover from, disturbances such as changes in storm discharge patterns associated with land use changes like expansion of agriculture and development of suburban housing tracts. The new laboratory and field research will have the primary objectives of: 1) refining and validating experimental techniques pertinent to the assessment of DOC utilization in streams: and 2) obtaining a few key measurements of DOC availability and turnover rates using these techniques. These activities are essential to further studies of the carbon cycle in streams. The research team that will conduct these studies is highly qualified. The Stroud Water Research Center will provide excellent institutional support for the research. The Ecosystem Studies Program recommends award of this grant.
