The Radiocarbon Signature of Microorganisms in the Mesopelagic Ocean

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The Radiocarbon Signature of Microorganisms in the Mesopelagic Ocean

Show simple item record Hansman, Roberta L. Griffin, Sheila Watson, Jordan T. Druffel, Ellen R. M. Ingalls, Anitra E. Pearson, Ann Aluwihare, Lihini I. 2010-08-30T17:14:16Z 2009
dc.identifier.citation Hansman, Roberta L., Sheila Griffin, Jordan T. Watson, Ellen R. M. Druffel, Anitra E. Ingalls, Ann Pearson, and Lihini I. Aluwihare. 2009. The radiocarbon signature of microorganisms in the mesopelagic ocean. Proceedings of the National Academy of Sciences of the United States of America 106(16): 6513-6518. en_US
dc.identifier.issn 0027-8424 en_US
dc.description.abstract Several lines of evidence indicate that microorganisms in the meso- and bathypelagic ocean are metabolically active and respiring carbon. In addition, growing evidence suggests that archaea are fixing inorganic carbon in this environment. However, direct quantification of the contribution from deep ocean carbon sources to community production in the dark ocean remains a challenge. In this study, carbon flow through the microbial community at 2 depths in the mesopelagic zone of the North Pacific Subtropical Gyre was examined by exploiting the unique radiocarbon signatures (Δ14C) of the 3 major carbon sources in this environment. The radiocarbon content of nucleic acids, a biomarker for viable cells, isolated from size-fractionated particles (0.2– 0.5 μm and >0.5 μm) showed the direct incorporation of carbon delivered by rapidly sinking particles. Most significantly, at the 2 mesopelagic depths examined (670 m and 915 m), carbon derived from in situ autotrophic fixation supported a significant fraction of the free-living microbial community (0.2– 0.5 μm size fraction), but the contribution of chemoautotrophy varied markedly between the 2 depths. Results further showed that utilization of the ocean’s largest reduced carbon reservoir, 14C-depleted, dissolved organic carbon, was negligible in this environment. This isotopic portrait of carbon assimilation by the in situ, free-living microbial community, integrated over >50,000 L of seawater, implies that recent, photosynthetic carbon is not always the major carbon source supporting microbial community production in the mesopelagic realm. en_US
dc.description.sponsorship Chemistry and Chemical Biology en_US
dc.language.iso en_US en_US
dc.publisher National Academy of Sciences en_US
dc.relation.isversionof doi:10.1073/pnas.0810871106 en_US
dc.relation.hasversion en_US
dash.license META_ONLY
dc.subject microbial metabolism en_US
dc.subject particle flux en_US
dc.subject particulate organic carbon (POC) en_US
dc.subject chemoautotrophy en_US
dc.title The Radiocarbon Signature of Microorganisms in the Mesopelagic Ocean en_US
dc.type Journal Article en_US
dc.description.version Version of Record en_US
dc.relation.journal Proceedings of the National Academy of Sciences of the United States of America en_US Pearson, Ann
dash.embargo.until 10000-01-01

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  • FAS Scholarly Articles [8227]
    Peer reviewed scholarly articles from the Faculty of Arts and Sciences of Harvard University

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