Present address: OEB Department, Harvard University, Cambridge, MA 02138, USA.
Environmental, biochemical and genetic drivers of DMSP degradation and DMS production in the Sargasso Sea
Article first published online: 10 FEB 2012
© 2012 Society for Applied Microbiology and Blackwell Publishing Ltd
Volume 14, Issue 5, pages 1210–1223, May 2012
How to Cite
Levine, N. M., Varaljay, V. A., Toole, D. A., Dacey, J. W. H., Doney, S. C. and Moran, M. A. (2012), Environmental, biochemical and genetic drivers of DMSP degradation and DMS production in the Sargasso Sea. Environmental Microbiology, 14: 1210–1223. doi: 10.1111/j.1462-2920.2012.02700.x
- Issue published online: 18 APR 2012
- Article first published online: 10 FEB 2012
- Received 7 October, 2011; revised 6 January, 2012; accepted 10 January, 2012.
Dimethylsulfide (DMS) is a climatically relevant trace gas produced and cycled by the surface ocean food web. Mechanisms driving intraannual variability in DMS production and dimethylsulfoniopropionate (DMSP) degradation in open-ocean, oligotrophic regions were investigated during a 10-month time-series at the Bermuda Atlantic Time-series Study site in the Sargasso Sea. Abundance and transcription of bacterial DMSP degradation genes, DMSP lyase enzyme activity, and DMS and DMSP concentrations, consumption rates and production rates were quantified over time and depth. This interdisciplinary data set was used to test current hypotheses of the role of light and carbon supply in regulating upper-ocean sulfur cycling. Findings supported UV-A-dependent phytoplankton DMS production. Bacterial DMSP degraders may also contribute significantly to DMS production when temperatures are elevated and UV-A dose is moderate, but may favour DMSP demethylation under low UV-A doses. Three groups of bacterial DMSP degraders with distinct intraannual variability were identified and niche differentiation was indicated. The combination of genetic and biochemical data suggest a modified ‘bacterial switch’ hypothesis where the prevalence of different bacterial DMSP degradation pathways is regulated by a complex set of factors including carbon supply, temperature and UV-A dose.