摘要

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.