Carbon-Nitrogen-Phosphorus Cyclingin Tomales Bay, California

Tomales Bay, California, has been the site oflong-term study of carbon-nitrogen-phospho-rus fluxes in the coastal zone. It has also one of severalcoastal sites being used for comparison of C-N-Pbiogeochemical fluxes. The site releases phosphorusand consumes dissolved nitrogen. It also producesdissolved inorganic carbon, mostly as elevatedalkalinity. The overall interpretation placed on thebiogeochemical fluxes is as follows. The system is netheterotrophic; that is, it consumes more organicmatter than it produces. A pathway of consumption thatis of particular importance to the nitrogen cycle isdenitrification. The combination of net heterotrophyand denitrification is the simultaneous release ofdissolved inorganic phosphorus and the uptake ofdissolved inorganic nitrogen. Much of the dissolvedinorganic carbon released during the net heterotrophyis bound in alkalinity, apparently the result ofsulfate reduction. Because this work can be traced by to the trainingthat one of the authors (SVS) received from KeithChave, it is appropriate to present a summary of theTomales Bay research in memory of Keith.