title: Cryptic carbon and sulfur cycling between surface ocean plankton.
abstract: About half the carbon fixed by phytoplankton in the ocean is taken up and metabolized by marine bacteria, a transfer that is mediated through the seawater dissolved organic carbon (DOC) pool. The chemical complexity of marine DOC, along with a poor understanding of which compounds form the basis of trophic interactions between bacteria and phytoplankton, have impeded efforts to identify key currencies of this carbon cycle link. Here, we used transcriptional patterns in a bacterial-diatom model system based on vitamin B12 auxotrophy as a sensitive assay for metabolite exchange between marine plankton. The most highly up-regulated genes (up to 374-fold) by a marine Roseobacter clade bacterium when cocultured with the diatom Thalassiosira pseudonana were those encoding the transport and catabolism of 2,3-dihydroxypropane-1-sulfonate (DHPS). This compound has no currently recognized role in the marine microbial food web. As the genes for DHPS catabolism have limited distribution among bacterial taxa, T. pseudonana may use this sulfonate for targeted feeding of beneficial associates. Indeed, DHPS was both a major component of the T. pseudonana cytosol and an abundant microbial metabolite in a diatom bloom in the eastern North Pacific Ocean. Moreover, transcript analysis of the North Pacific samples provided evidence of DHPS catabolism by Roseobacter populations. Other such biogeochemically important metabolites may be common in the ocean but difficult to discriminate against the complex chemical background of seawater. Bacterial transformation of this diatom-derived sulfonate represents a previously unidentified and likely sizeable link in both the marine carbon and sulfur cycles.
authors.affiliation: Department of Microbiology, University of Georgia, Athens, GA 30602;
authors.forename: Bryndan P
authors.initials: BP
authors.lastname: Durham
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, GA 30602;
authors.forename: Shalabh
authors.initials: S
authors.lastname: Sharma
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, GA 30602;
authors.forename: Haiwei
authors.initials: H
authors.lastname: Luo
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, GA 30602;
authors.forename: Christa B
authors.initials: CB
authors.lastname: Smith
authors.affiliation: School of Oceanography, University of Washington, Seattle, WA 98195;
authors.forename: Shady A
authors.initials: SA
authors.lastname: Amin
authors.affiliation: Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543; and.
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Bender
authors.affiliation: Department of Chemistry, University of Tennessee, Knoxville, TN 37996.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Dearth
authors.affiliation: Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543; and.
authors.forename: Benjamin A S
authors.initials: BA
authors.lastname: Van Mooy
authors.affiliation: Department of Chemistry, University of Tennessee, Knoxville, TN 37996.
authors.forename: Shawn R
authors.initials: SR
authors.lastname: Campagna
authors.affiliation: Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543; and.
authors.forename: Elizabeth B
authors.initials: EB
authors.lastname: Kujawinski
authors.affiliation: School of Oceanography, University of Washington, Seattle, WA 98195;
authors.forename: E Virginia
authors.initials: EV
authors.lastname: Armbrust
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, GA 30602; mmoran@uga.edu.
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Moran
mesh_terms: D000476:Alkanesulfonates / Q000378:metabolism; D057486:Carbon Cycle; D017377:Diatoms / Q000235:genetics / Q000378:metabolism; D017753:Ecosystem; D020869:Gene Expression Profiling; D053858:Metabolic Networks and Pathways / Q000235:genetics; D008954:Models, Biological; D010802:Phylogeny; D010839:Phytoplankton / Q000235:genetics / Q000378:metabolism; D010933:Plankton / Q000235:genetics / Q000378:metabolism*; D041904:Roseobacter / Q000235:genetics / Q000378:metabolism; D012623:Seawater / Q000382:microbiology; D013455:Sulfur / Q000378:metabolism*; D014805:Vitamin B 12 / Q000378:metabolism
chemical_list: C551265:2,3-dihydroxypropane-1-sulfonate; D000476:Alkanesulfonates; D013455:Sulfur; D014805:Vitamin B 12
keywords: DHPS; bacteria; diatoms; sulfonates; vitamin B12