Cyanobacteria and cyanophage contributions to carbon and nitrogen cycling in an oligotrophic oxygen-deficient zone.

Autor: Fuchsman CA; School of Oceanography, University of Washington, Seattle, WA, USA. cfuchsman@umces.edu.; Horn Point Laboratory, University of Maryland, Cambridge, MD, USA. cfuchsman@umces.edu., Palevsky HI; School of Oceanography, University of Washington, Seattle, WA, USA.; Geosciences Department, Wellesley College, Wellesley, MA, USA., Widner B; Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.; Department of Ocean, Earth and Atmospheric Sciences, Old Dominion University, Norfolk, VA, USA., Duffy M; School of Oceanography, University of Washington, Seattle, WA, USA., Carlson MCG; School of Oceanography, University of Washington, Seattle, WA, USA.; Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel., Neibauer JA; School of Oceanography, University of Washington, Seattle, WA, USA., Mulholland MR; Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA., Keil RG; School of Oceanography, University of Washington, Seattle, WA, USA., Devol AH; School of Oceanography, University of Washington, Seattle, WA, USA., Rocap G; School of Oceanography, University of Washington, Seattle, WA, USA. rocap@uw.edu.
Jazyk: angličtina
Zdroj: The ISME journal [ISME J] 2019 Nov; Vol. 13 (11), pp. 2714-2726. Date of Electronic Publication: 2019 Jun 27.
DOI: 10.1038/s41396-019-0452-6
Abstrakt: Up to half of marine N losses occur in oxygen-deficient zones (ODZs). Organic matter flux from productive surface waters is considered a primary control on N 2 production. Here we investigate the offshore Eastern Tropical North Pacific (ETNP) where a secondary chlorophyll a maximum resides within the ODZ. Rates of primary production and carbon export from the mixed layer and productivity in the primary chlorophyll a maximum were consistent with oligotrophic waters. However, sediment trap carbon and nitrogen fluxes increased between 105 and 150 m, indicating organic matter production within the ODZ. Metagenomic and metaproteomic characterization indicated that the secondary chlorophyll a maximum was attributable to the cyanobacterium Prochlorococcus, and numerous photosynthesis and carbon fixation proteins were detected. The presence of chemoautotrophic ammonia-oxidizing archaea and the nitrite oxidizer Nitrospina and detection of nitrate oxidoreductase was consistent with cyanobacterial oxygen production within the ODZ. Cyanobacteria and cyanophage were also present on large (>30 μm) particles and in sediment trap material. Particle cyanophage-to-host ratio exceeded 50, suggesting that viruses help convert cyanobacteria into sinking organic matter. Nitrate reduction and anammox proteins were detected, congruent with previously reported N 2 production. We suggest that autochthonous organic matter production within the ODZ contributes to N 2 production in the offshore ETNP.
Databáze: MEDLINE
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