Vertical partitioning of phosphate uptake among picoplankton groups in the low Pi Mediterranean Sea

Handle URI:
http://hdl.handle.net/10754/346734
Title:
Vertical partitioning of phosphate uptake among picoplankton groups in the low Pi Mediterranean Sea
Authors:
Talarmin, A. ( 0000-0002-7249-1297 ) ; Van Wambeke, F.; Lebaron, P.; Moutin, T.
Abstract:
Microbial transformations are key processes in marine phosphorus cycling. In this study, we investigated the contribution of phototrophic and heterotrophic groups to phosphate (Pi) uptake fluxes in the euphotic zone of the low-Pi Mediterranean Sea and estimated Pi uptake kinetic characteristics. Surface soluble reactive phosphorus (SRP) concentrations were in the range of 6-80 nmol Lg'1 across the transect, and the community Pi turnover times, assessed using radiolabeled orthophosphate incubations, were longer in the western basin, where the highest bulk and cellular rates were measured. Using live cell sorting, four vertical profiles of Pi uptake rates were established for heterotrophic prokaryotes (Hprok), phototrophic picoeukaryotes (Pic) and <i>Prochlorococcus</i> (Proc) and <i>Synechococcus</i> (Syn) cyanobacteria. Hprok cells contributed up to 82% of total Pi uptake fluxes in the superficial euphotic zone, through constantly high abundances (2.7-10.2 × 105 cells mLg'1) but variable cellular rates (6.6 ± 9.3 amol P cellg'1 hg'1). Cyanobacteria achieved most of the Pi uptake (up to 62%) around the deep chlorophyll maximum depth, through high abundances (up to 1.4 × 105 Proc cells mLg'1) and high cellular uptake rates (up to 40 and 402 amol P cellg'1 hg'1, respectively for Proc and Syn cells). At saturating concentrations, maximum cellular rates up to 132 amol P cellg'1 hg'1 were measured for Syn at station (St.) C, which was 5 and 60 times higher than Proc and Hprok, respectively. Pi uptake capabilities of the different groups likely contribute to their vertical distribution in the low Pi Mediterranean Sea, possibly along with other energy limitations.
KAUST Department:
Red Sea Research Center (RSRC)
Citation:
Vertical partitioning of phosphate uptake among picoplankton groups in the low Pi Mediterranean Sea 2015, 12 (4):1237 Biogeosciences
Publisher:
Copernicus GmbH
Journal:
Biogeosciences
Issue Date:
26-Feb-2015
DOI:
10.5194/bg-12-1237-2015
Type:
Article
ISSN:
1726-4189
Additional Links:
http://www.biogeosciences.net/12/1237/2015/
Appears in Collections:
Articles; Red Sea Research Center (RSRC)

Full metadata record

DC FieldValue Language
dc.contributor.authorTalarmin, A.en
dc.contributor.authorVan Wambeke, F.en
dc.contributor.authorLebaron, P.en
dc.contributor.authorMoutin, T.en
dc.date.accessioned2015-03-17T13:21:32Zen
dc.date.available2015-03-17T13:21:32Zen
dc.date.issued2015-02-26en
dc.identifier.citationVertical partitioning of phosphate uptake among picoplankton groups in the low Pi Mediterranean Sea 2015, 12 (4):1237 Biogeosciencesen
dc.identifier.issn1726-4189en
dc.identifier.doi10.5194/bg-12-1237-2015en
dc.identifier.urihttp://hdl.handle.net/10754/346734en
dc.description.abstractMicrobial transformations are key processes in marine phosphorus cycling. In this study, we investigated the contribution of phototrophic and heterotrophic groups to phosphate (Pi) uptake fluxes in the euphotic zone of the low-Pi Mediterranean Sea and estimated Pi uptake kinetic characteristics. Surface soluble reactive phosphorus (SRP) concentrations were in the range of 6-80 nmol Lg'1 across the transect, and the community Pi turnover times, assessed using radiolabeled orthophosphate incubations, were longer in the western basin, where the highest bulk and cellular rates were measured. Using live cell sorting, four vertical profiles of Pi uptake rates were established for heterotrophic prokaryotes (Hprok), phototrophic picoeukaryotes (Pic) and <i>Prochlorococcus</i> (Proc) and <i>Synechococcus</i> (Syn) cyanobacteria. Hprok cells contributed up to 82% of total Pi uptake fluxes in the superficial euphotic zone, through constantly high abundances (2.7-10.2 × 105 cells mLg'1) but variable cellular rates (6.6 ± 9.3 amol P cellg'1 hg'1). Cyanobacteria achieved most of the Pi uptake (up to 62%) around the deep chlorophyll maximum depth, through high abundances (up to 1.4 × 105 Proc cells mLg'1) and high cellular uptake rates (up to 40 and 402 amol P cellg'1 hg'1, respectively for Proc and Syn cells). At saturating concentrations, maximum cellular rates up to 132 amol P cellg'1 hg'1 were measured for Syn at station (St.) C, which was 5 and 60 times higher than Proc and Hprok, respectively. Pi uptake capabilities of the different groups likely contribute to their vertical distribution in the low Pi Mediterranean Sea, possibly along with other energy limitations.en
dc.publisherCopernicus GmbHen
dc.relation.urlhttp://www.biogeosciences.net/12/1237/2015/en
dc.rightsThis work is distributed under the Creative Commons Attribution 3.0 License.en
dc.titleVertical partitioning of phosphate uptake among picoplankton groups in the low Pi Mediterranean Seaen
dc.typeArticleen
dc.contributor.departmentRed Sea Research Center (RSRC)en
dc.identifier.journalBiogeosciencesen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionAix Marseille Université, Mediterranean Institute of Oceanography (MIO), 13288, Marseille, CEDEX 9, Franceen
dc.contributor.institutionUniversité de Toulon, 83957, CNRS-INSU/IRD, Franceen
dc.contributor.institutionSorbonne Universités, UPMC Univ. Paris 06, USR 3579, LBBM, Observatoire Océanologique, 66650, Banyuls-sur-Mer, Franceen
dc.contributor.institutionCNRS, USR 3579, LBBM, Observatoire Océanologique, 66650 Banyuls-sur-Mer, Franceen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorTalarmin, A.en
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