Mou, X., S. Sun, R. A. Edwards, R. E. Hodson, and M. A. Moran. 2008. Bacterial carbon processing by generalist species in the coastal ocean. Nature 451:708-711.

The assimilation and mineralization of dissolved organic carbon (DOC) by marine bacterioplankton is a major process in the ocean carbon cycle. Little information exists, however, on the specific metabolic functions of participating bacteria, and whether individual taxa specialize on particular components of the marine DOC pool. Here we use experimental metagenomics to show that coastal communities are populated by taxa capable of metabolizing a wide variety of organic carbon compounds. Genomic DNA captured from bacterial community subsets metabolizing single components of the DOC pool showed substantial overlap in gene composition as well as a diversity of carbon processing capabilities beyond the selected phenotypes. This first direct measure of niche breadth for bacterial functional assemblages suggests that, in accordance with ecological theory, heterogeneity in composition and supply of organic carbon to coastal oceans may favor generalist bacteria. In the important interplay between microbial community structure and biogeochemical cycling, coastal heterotrophic communities may be controlled less by transient changes in the carbon reservoir they process and more by factors such as trophic interactions and physical conditions.