9523466 Smith The coastal bays play a critical role in the transport and transformation of land runoff to the ocean. Drs. Hollibaugh and Smith will consider the role of bays and estuaries in the net flux of carbon, nitrogen, and phosphorous between the land and ocean. The system of interest (Tomales Bay, California) is hydrographically simple, has a long water residence time, is sufficiently compact that it can be studied as a single unit, and has low inorganic nutrient population. The system functions metabolically like numerous other coastal marine ecosystems. External sources of organic matter which support food chains in this system are simple to characterize and have strong seasonal and interannual signals. These investigators will address the following questions by means of a multi-investigator field and laboratory program: 1) What is the relative importance of coastal upwelling versus terrigenous runoff in delivering oxidizable organic matter and nutrients to this system? 2) What are the responses of system metabolism and the metabolism of major system components to seasonal and interannual variations in these forcing functions? 3) What is the relationship between net system metabolism and non-conservative fluxes of nitrogen? 4) Can rates derived from stoichimetric arguments be validated by "direct" biochemical assays. It is anticipated that the outcome of this research can be extrpolated to other systems which may be applicable to management of the nations resources. This effort is being funded as a Land Margins Ecosystem Research project in a program which is jointly supported by the Directorates of Geosciences and Biotic Systems and Resources.
