Latitudinal gradients in degradation of marine dissolved organic carbon

Research output: Research - peer-reviewJournal article

  • Carol Arnosti
    Carol ArnostiDepartment of Marine Sciences, University of North Carolina at Chapel HillUnited States
  • Andrew Steen
    Andrew SteenDenmark
  • Kai Ziervogel
    Kai ZiervogelDepartment of Marine Sciences, University of North Carolina at Chapel HillUnited States
  • Sherif Ghobrial
    Sherif GhobrialDepartment of Marine Sciences, University of North Carolina at Chapel HillUnited States
  • Wade Jeffrey
    Wade JeffreyDepartment of Biology, University of West FloridaUnited States
Heterotrophic microbial communities cycle nearly half of net primary productivity in the ocean, and play a particularly important role in transformations of dissolved organic carbon (DOC). The specific means by which these communities mediate the transformations of organic carbon are largely unknown, since the vast majority of marine bacteria have not been isolated in culture, and most measurements of DOC degradation rates have focused on uptake and metabolism of either bulk DOC or of simple model compounds (e.g. specific amino acids or sugars). Genomic investigations provide information about the potential capabilities of organisms and communities but not the extent to which such potential is expressed. We tested directly the capabilities of heterotrophic microbial communities in surface ocean waters at 32 stations spanning latitudes from 76 ºS to 79 ºN to hydrolyze a range of high molecular weight organic substrates and thereby initiate organic matter degradation. These data demonstrate the existence of a latitudinal gradient in the range of complex substrates available to heterotrophic microbial communities, paralleling the global gradient in bacterial species richness. As changing climate increasingly affects the marine environment, changes in the spectrum of substrates accessible by microbial communities may lead to shifts in the location and rate at which marine DOC is respired. Since the inventory of DOC in the ocean is comparable in magnitude to the atmospheric CO2 reservoir, such a change could profoundly affect the global carbon cycle.
Original languageEnglish
JournalP L o S One
Issue number12
Pages (from-to)e28900
Number of pages6
StatePublished - 29 Dec 2011

    Research areas

  • extracellular enzymes, biogeography, Dissolved organic carbon

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