Please use this identifier to cite or link to this item: http://hdl.handle.net/1893/20028
Appears in Collections:Biological and Environmental Sciences Journal Articles
Peer Review Status: Refereed
Title: Denitrifying alphaproteobacteria from the Arabian Sea that express nosZ, the gene encoding nitrous oxide reductase, in oxic and suboxic waters
Authors: Wyman, Michael
Hodgson, Sylvia
Bird, Clare
Contact Email: michael.wyman@stir.ac.uk
Issue Date: Apr-2013
Publisher: American Society for Microbiology
Citation: Wyman M, Hodgson S & Bird C (2013) Denitrifying alphaproteobacteria from the Arabian Sea that express nosZ, the gene encoding nitrous oxide reductase, in oxic and suboxic waters, Applied and Environmental Microbiology, 79 (8), pp. 2670-2681.
Abstract: Marine ecosystems are significant sources of the powerful greenhouse gas nitrous oxide (N2O). A by-product of nitrification and an intermediate in the denitrification pathway, N2O is formed primarily in oxygen-deficient waters and sediments. We describe the isolation of a group of alphaproteobacteria from the suboxic waters of the Arabian Sea that are phylogenetically affiliated with Labrenzia spp. and other denitrifiers. Quantitative PCR assays revealed that these organisms were very broadly distributed in this semienclosed ocean basin. Their biogeographical range extended from the productive, upwelling region off the Omani shelf to the clear, oligotrophic waters that are found much further south and also included the mesotrophic waters overlying the oxygen minimum zone (OMZ) in the northeastern sector of the Arabian Sea. These organisms actively expressed NosZ (N2O reductase, the terminal step in the denitrification pathway) within the OMZ, an established region of pelagic denitrification. They were found in greatest numbers outside the OMZ, however, and nosZ mRNAs were also readily detected near the base of the upper mixed layer in nutrient-poor, oxic regions. Our findings provide firm molecular evidence of a potential sink for N2O within well-ventilated, oceanic surface waters in this biogeochemically important region. We show that the Labrenzia-like denitrifiers and their close relatives are habitual colonizers of the pseudobenthic environment provided by Trichodesmium spp. We develop the conjecture that the O2-depleted microzones that occur within the colonies of these filamentous, diazotrophic cyanobacteria might provide unexpected niches for the reduction of nitrogen oxides in tropical and subtropical surface waters.
Type: Journal Article
URI: http://hdl.handle.net/1893/20028
DOI Link: http://dx.doi.org/10.1128/AEM.03705-12
Rights: The publisher does not allow this work to be made publicly available in this Repository. Please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study.
Affiliation: Biological and Environmental Sciences
Biological and Environmental Sciences
Biological and Environmental Sciences

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