Microbes Work Together to Process Dissolved Organic Carbon


Marine dissolved organic matter (DOM) contains as much carbon as the Earth’s atmosphere and represents a critical component of the global carbon cycle. While we know that microbial processes and activities drive most of Earth’s biogeochemical cycles, those associated with marine DOM cycling are poorly understood. DOE scientists at the Massachusetts Institute of Technology analyzed the responses of microbial communities to high-molecular weight DOM. Following the addition of DOM both cell numbers and a variety of gene transcripts from different microbial groups doubled over a 27 hour period. Gene transcripts that were increased included those associated with sensor systems, phosphate and nitrogen processing, chemotaxis, and motility. The data also indicated that different microbial species played different roles in the partitioning of DOM. These findings suggest that coordinated, cooperative activities of a variety of bacterial “specialists” may be critical in the cycling of marine DOM, emphasizing the importance of microbial community dynamics in the global carbon cycle. The research was led by Edward F. DeLong and has just been published on-line in the Proceedings of the National Academy of Sciences (PNAS).


McCarren, J, Becker, J.W., Repeta, D.J., Shia, Y., Young, C.R., Malmstrom, R.R., Chisholm, S.W. and DeLong, E.F. “Microbial community transcriptomes reveal microbes and metabolic pathways associated with dissolved organic matter turnover in the sea” PNAS (2010) www.pnas.org/cgi/doi/10.1073/pnas.1010732107.