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dc.contributor.authorBernhard, Joan M.  Concept link
dc.contributor.authorCasciotti, Karen L.  Concept link
dc.contributor.authorMcIlvin, Matthew R.  Concept link
dc.contributor.authorBeaudoin, David J.  Concept link
dc.contributor.authorVisscher, Pieter T.  Concept link
dc.contributor.authorEdgcomb, Virginia P.  Concept link
dc.date.accessioned2012-08-07T15:55:33Z
dc.date.available2014-10-22T08:57:23Z
dc.date.issued2012-07-03
dc.identifier.citationJournal of Geophysical Research 117 (2012): G03002en_US
dc.identifier.urihttps://hdl.handle.net/1912/5292
dc.descriptionAuthor Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 117 (2012): G03002, doi:10.1029/2012JG001949.en_US
dc.description.abstractUntil recently, the process of denitrification (conversion of nitrate or nitrite to gaseous products) was thought to be performed exclusively by prokaryotes and fungi. The finding that foraminifera perform complete denitrification could impact our understanding of nitrate removal in sediments as well as our understanding of eukaryotic respiration, especially if it is widespread. However, details of this process and the subcellular location of these reactions in foraminifera remain uncertain. For example, prokaryotic endobionts, rather than the foraminifer proper, could perform denitrification, as has been shown recently in an allogromiid foraminifer. Here, intracellular nitrate concentrations and isotope ratios (δ15NNO3 and δ18ONO3) were measured to assess the nitrate dynamics in four benthic foraminiferal species (Bolivina argentea, Buliminella tenuata, Fursenkoina cornuta, Nonionella stella) with differing cellular architecture and associations with microbial endobionts, recovered from Santa Barbara Basin, California. Cellular nitrate concentrations were high (12–217 mM) in each species, and intracellular nitrate often had elevated δ15NNO3 and δ18ONO3 values. Experiments including suboxic and anoxic incubations of B. argentea revealed a decrease in intracellular nitrate concentration and an increase in δ15NNO3 and δ18ONO3 over time, indicating nitrate respiration and/or denitrification within the foraminifera. Results illustrate that nitrate reduction occurs in a range of foraminiferal species, including some possessing endobionts (including a chloroplast-sequestering species) and others lacking endobionts, implying that microbial associates may not solely be responsible for this process in foraminifera. Furthermore, we show that benthic foraminifera may represent important reservoirs of nitrate storage in sediments, as well as mediators of its removal.en_US
dc.description.sponsorshipThis research was supported by NSF grant EF-0702491 to JMB, KLC, and VPE.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttps://doi.org/10.1029/2012JG001949
dc.subjectSSU rRNAen_US
dc.subjectSanta Barbara Basinen_US
dc.subjectDenitrificationen_US
dc.subjectNirKen_US
dc.subjectNirSen_US
dc.subjectSymbiosisen_US
dc.titlePotential importance of physiologically diverse benthic foraminifera in sedimentary nitrate storage and respirationen_US
dc.typeArticleen_US
dc.description.embargo2013-01-03en_US
dc.identifier.doi10.1029/2012JG001949


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