The title of this article may seem a bit presumptuous or at least premature in the sense that marine microbiologists have only quite recently entered the quantitative phase of their investigations of the distribution, biomass, and in situ metabolic activities of sea microbes. Nevertheless, I believe that summarizing the results of preliminary studies will serve to define more clearly the important questions and will help to formulate a more productive research prospectus. Throughout this discussion I will attempt to identify what I consider to be important prospects for future oceanographic investigations.
The central theme that I would like to consider is that of microbially mediated transformations of carbon at oceanic interfaces. There are at least two major ideas to pursue and develop: