Dissolved Organic Carbon (DOC) is an organic substrate that fuels heterotrophic microbial production, and as a result of microbial production organic matter is re-mineralized.  DOC source and fate, and microbial processes, therefore have important implications for biogeochemical cycling in marine ecosystems.  In the Santa Barbara Coastal ecosystem the continental shelf is extremely narrow, being only a few kilometers wide in many areas, allowing greater potential for cross-shelf processes and supply of offshore resources to the near-shore rocky reef environment. 

In this study we determined the temporal variation in magnitude and direction of cross shelf gradients in dissolved organic carbon and assessed heterotrophic bacterioplankton dynamics in response to observed DOC variability. Monthly oceanographic cruises were conducted in the Santa Barbara Channel over a 3km transect from a near-shore rocky reef across the continental shelf into the channel from January 2008-April 2009. DOC removal processes across the shelf were elucidated using a combination of chemical characterization assays and molecular characterization of microbial communities.