Dietary effects on abundance and carbon utilization ability of DMSP-consuming bacteria associated with the copepod Acartia tonsa Dana

Abstract

Dimethylsulfoniopropionate (DMSP) is a ubiquitous methylated compound in the ocean and a precursor of the climatically active gas dimethyl sulfide (DMS). Copepods have been shown to contain DMSP-consuming bacteria (DCB) in their bodies, which could exploit DMSP ingested by the copepods and attain fast growth. We compared the DCB abundances associated with the copepod Acartia tonsa Dana that were fed different microalgae. DCB recovered from the copepods were used in enrichment experiments to study their ability to grow on different methylated compounds. Our results showed that DCB abundance associated with A. tonsa was independent of dietary DMSP content. The DCB were able to grow on carbon sources other than DMSP, indicating their ability to assimilate both carboxyl chain carbon and methyl carbon. The independence from food DMSP content and versatility in carbon substrate utilization would allow DCB to maintain a viable population among zooplankton, even in DMSP-poor conditions. Coupling between DCB and zooplankton therefore represents a persistent and potentially important sink of DMSP in the ocean.

Keywords:

• Dimethylsulfoniopropionate
• copepod
• most probable number
• carbon utilization
• methyl group

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

This work was supported by the China Scholarship Council, National Natural Science Foundation of China (No. 41030858) and the US National Science Foundation (OCE-0814558). The authors thank Samantha Bickel for her technical assistance.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark