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dc.contributor.authorKrupke, Andreas  Concept link
dc.contributor.authorMohr, Wiebke  Concept link
dc.contributor.authorLaRoche, Julie  Concept link
dc.contributor.authorFuchs, Bernhard M.  Concept link
dc.contributor.authorAmann, Rudolf I.  Concept link
dc.contributor.authorKuypers, Marcel M. M.  Concept link
dc.date.accessioned2015-08-06T17:59:37Z
dc.date.available2015-08-06T17:59:37Z
dc.date.issued2014-11-19
dc.identifier.urihttps://hdl.handle.net/1912/7455
dc.descriptionAuthor Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in ISME Journal 9 (2015): 1635–1647, doi:10.1038/ismej.2014.253.en_US
dc.description.abstractSymbiotic relationships between phytoplankton and N2-fixing microorganisms play a crucial role in marine ecosystems. The abundant and widespread unicellular cyanobacteria group A (UCYN-A) has recently been found to live symbiotically with a haptophyte. Here, we investigated the effect of nitrogen (N), phosphorus (P), iron (Fe) and Saharan dust additions on nitrogen (N2) fixation and primary production by the UCYN-A-haptophyte association in the subtropical eastern North Atlantic Ocean using nifH expression analysis and stable isotope incubations combined with single cell measurements. N2 fixation by UCYN-A was stimulated by the addition of Fe and Saharan dust although this was not reflected in the nifH expression. CO2 fixation by the haptophyte was stimulated by the addition of ammonium nitrate as well as Fe and Saharan dust. Intriguingly, the single-cell analysis using nanoSIMS indicates that the increased CO2 fixation by the haptophyte in treatments without added fixed N is likely an indirect result of the positive effect of Fe and/or P on UCYN-A N2 fixation and the transfer of N2-derived N to the haptophyte. Our results reveal a direct linkage between the marine carbon and nitrogen cycles that is fuelled by the atmospheric deposition of dust. The comparison of single-cell rates suggests a tight coupling of nitrogen and carbon transfer that stays balanced even under changing nutrient regimes. However, it appears that the transfer of carbon from the haptophyte to UCYN-A requires a transfer of nitrogen from UCYN-A. This tight coupling indicates an obligate symbiosis of this globally important diazotrophic association.en_US
dc.description.sponsorshipWe thank Surface Ocean Processes in the Anthropocene (Sopran) and the Sonderforschungsbereich SFB754 for financial support. This study was funded by the Max Planck Society.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.relation.urihttps://doi.org/10.1038/ismej.2014.253
dc.subjectDiazotrophsen_US
dc.subjectDouble CARD–FISHen_US
dc.subjectN2 fixationen_US
dc.subjectNanoSIMSen_US
dc.subjectSaharan dusten_US
dc.subjectSingle–cellen_US
dc.titleThe effect of nutrients on carbon and nitrogen fixation by the UCYN-A–haptophyte symbiosisen_US
dc.typePreprinten_US


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