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<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en">Geographical gradients of dissolved Vitamin B<sub>12</sub> in the Mediterranean Sea</title><author><name sortKey="Bonnet, S" sort="Bonnet, S" uniqKey="Bonnet S" first="S." last="Bonnet">S. Bonnet</name><affiliation><nlm:aff id="aff1"><institution>IRD, MIO, UM 110 - IRD Centre of Noumea, Aix-Marseille University, University of South Toulon Var, CNRS/INSU</institution><country>Noumea, New Caledonia, France</country></nlm:aff></affiliation></author><author><name sortKey="Tovar Sanchez, A" sort="Tovar Sanchez, A" uniqKey="Tovar Sanchez A" first="A." last="Tovar-Sánchez">A. Tovar-Sánchez</name><affiliation><nlm:aff id="aff2"><institution>Department of Global Change Research, IMEDEA (CSIC-UIB), Instituto Mediterráneo de Estudios Avanzados</institution><country>Esporles Balearic Islands, Spain</country></nlm:aff></affiliation></author><author><name sortKey="Panzeca, C" sort="Panzeca, C" uniqKey="Panzeca C" first="C." last="Panzeca">C. Panzeca</name><affiliation><nlm:aff id="aff3"><institution>Department of Biological Sciences, University of Southern California</institution><country>Los Angeles, CA, USA</country></nlm:aff></affiliation></author><author><name sortKey="Duarte, C M" sort="Duarte, C M" uniqKey="Duarte C" first="C. M." last="Duarte">C. M. Duarte</name><affiliation><nlm:aff id="aff2"><institution>Department of Global Change Research, IMEDEA (CSIC-UIB), Instituto Mediterráneo de Estudios Avanzados</institution><country>Esporles Balearic Islands, Spain</country></nlm:aff></affiliation><affiliation><nlm:aff id="aff4"><institution>The UWA Oceans Institute, The University of Western Australia</institution><country>Crawley, WA, Australia</country></nlm:aff></affiliation></author><author><name sortKey="Ortega Retuerta, E" sort="Ortega Retuerta, E" uniqKey="Ortega Retuerta E" first="E." last="Ortega-Retuerta">E. Ortega-Retuerta</name><affiliation><nlm:aff id="aff5"><institution>Departament Biologia Marina i Oceanografia, Institut de Ciències del Mar, CSIC</institution><country>Barcelona, Spain</country></nlm:aff></affiliation></author><author><name sortKey="Sa Udo Wilhelmy, S A" sort="Sa Udo Wilhelmy, S A" uniqKey="Sa Udo Wilhelmy S" first="S. A." last="Sa Udo-Wilhelmy">S. A. Sa Udo-Wilhelmy</name><affiliation><nlm:aff id="aff5"><institution>Departament Biologia Marina i Oceanografia, Institut de Ciències del Mar, CSIC</institution><country>Barcelona, Spain</country></nlm:aff></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">PMC</idno><idno type="pmid">23772225</idno><idno type="pmc">3677149</idno><idno type="url">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3677149</idno><idno type="RBID">PMC:3677149</idno><idno type="doi">10.3389/fmicb.2013.00126</idno><date when="2013">2013</date><idno type="wicri:Area/Pmc/Corpus">002496</idno><idno type="wicri:explorRef" wicri:stream="Pmc" wicri:step="Corpus" wicri:corpus="PMC">002496</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en" level="a" type="main">Geographical gradients of dissolved Vitamin B<sub>12</sub> in the Mediterranean Sea</title><author><name sortKey="Bonnet, S" sort="Bonnet, S" uniqKey="Bonnet S" first="S." last="Bonnet">S. Bonnet</name><affiliation><nlm:aff id="aff1"><institution>IRD, MIO, UM 110 - IRD Centre of Noumea, Aix-Marseille University, University of South Toulon Var, CNRS/INSU</institution><country>Noumea, New Caledonia, France</country></nlm:aff></affiliation></author><author><name sortKey="Tovar Sanchez, A" sort="Tovar Sanchez, A" uniqKey="Tovar Sanchez A" first="A." last="Tovar-Sánchez">A. Tovar-Sánchez</name><affiliation><nlm:aff id="aff2"><institution>Department of Global Change Research, IMEDEA (CSIC-UIB), Instituto Mediterráneo de Estudios Avanzados</institution><country>Esporles Balearic Islands, Spain</country></nlm:aff></affiliation></author><author><name sortKey="Panzeca, C" sort="Panzeca, C" uniqKey="Panzeca C" first="C." last="Panzeca">C. Panzeca</name><affiliation><nlm:aff id="aff3"><institution>Department of Biological Sciences, University of Southern California</institution><country>Los Angeles, CA, USA</country></nlm:aff></affiliation></author><author><name sortKey="Duarte, C M" sort="Duarte, C M" uniqKey="Duarte C" first="C. M." last="Duarte">C. M. Duarte</name><affiliation><nlm:aff id="aff2"><institution>Department of Global Change Research, IMEDEA (CSIC-UIB), Instituto Mediterráneo de Estudios Avanzados</institution><country>Esporles Balearic Islands, Spain</country></nlm:aff></affiliation><affiliation><nlm:aff id="aff4"><institution>The UWA Oceans Institute, The University of Western Australia</institution><country>Crawley, WA, Australia</country></nlm:aff></affiliation></author><author><name sortKey="Ortega Retuerta, E" sort="Ortega Retuerta, E" uniqKey="Ortega Retuerta E" first="E." last="Ortega-Retuerta">E. Ortega-Retuerta</name><affiliation><nlm:aff id="aff5"><institution>Departament Biologia Marina i Oceanografia, Institut de Ciències del Mar, CSIC</institution><country>Barcelona, Spain</country></nlm:aff></affiliation></author><author><name sortKey="Sa Udo Wilhelmy, S A" sort="Sa Udo Wilhelmy, S A" uniqKey="Sa Udo Wilhelmy S" first="S. A." last="Sa Udo-Wilhelmy">S. A. Sa Udo-Wilhelmy</name><affiliation><nlm:aff id="aff5"><institution>Departament Biologia Marina i Oceanografia, Institut de Ciències del Mar, CSIC</institution><country>Barcelona, Spain</country></nlm:aff></affiliation></author></analytic><series><title level="j">Frontiers in Microbiology</title><idno type="eISSN">1664-302X</idno><imprint><date when="2013">2013</date></imprint></series></biblStruct></sourceDesc></fileDesc><profileDesc><textClass></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en"><p>Most eukaryotic phytoplankton require vitamin B<sub>12</sub> to grow. However, the cycling of this organic growth factor has received substantially less attention than other bioactive substances such as trace metals in the marine environment. This is especially true in the Mediterranean Sea, where direct measurements of dissolved vitamins have never been reported. We report here the first direct measurements of dissolved vitamin B<sub>12</sub> across longitudinal gradients in Mediterranean waters. The range of vitamin B<sub>12</sub> concentrations measured over the whole transect was 0.5–6.2 pM, which is slightly higher than the range (undetectable—4 pM) of ambient concentrations measured in other open ocean basins in the Pacific and Atlantic oceans. The concentrations measured in the western basin were significantly higher (<italic>p</italic> < 0.05) than those of the eastern basin. They were positively correlated with chlorophyll concentrations in the most western part of the basin, and did not show any significant correlation with any other biological variables in other regions of the sampling transect.</p></div></front><back><div1 type="bibliography"><listBibl><biblStruct><analytic><author><name sortKey="Bertrand, E M" uniqKey="Bertrand E">E. M. Bertrand</name></author><author><name sortKey="Saito, M A" uniqKey="Saito M">M. A. Saito</name></author><author><name sortKey="Rose, J M" uniqKey="Rose J">J. M. Rose</name></author><author><name sortKey="Riesselman, C R" uniqKey="Riesselman C">C. R. Riesselman</name></author><author><name sortKey="Lohan, M C" uniqKey="Lohan M">M. C. Lohan</name></author><author><name sortKey="Noble, A E" uniqKey="Noble A">A. E. Noble</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Bethoux, J P" uniqKey="Bethoux J">J. P. Bethoux</name></author><author><name sortKey="Morin, P" uniqKey="Morin P">P. Morin</name></author><author><name sortKey="Ruiz Pino, D P" uniqKey="Ruiz Pino D">D. P. Ruiz-Pino</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Bonnet, S" uniqKey="Bonnet S">S. Bonnet</name></author><author><name sortKey="Guieu, C" uniqKey="Guieu C">C. Guieu</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Bonnet, S" uniqKey="Bonnet S">S. Bonnet</name></author><author><name sortKey="Guieu, C" uniqKey="Guieu C">C. Guieu</name></author><author><name sortKey="Chiaverini, J" uniqKey="Chiaverini J">J. Chiaverini</name></author><author><name sortKey="Ras, J" uniqKey="Ras J">J. Ras</name></author><author><name sortKey="Stock, A" uniqKey="Stock A">A. Stock</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Bonnet, S" uniqKey="Bonnet S">S. Bonnet</name></author><author><name sortKey="Webb, E" uniqKey="Webb E">E. Webb</name></author><author><name sortKey="Panzeca, C" uniqKey="Panzeca C">C. Panzeca</name></author><author><name sortKey="Karl, D M" uniqKey="Karl D">D. M. Karl</name></author><author><name sortKey="Capone, D G" uniqKey="Capone D">D. G. Capone</name></author><author><name sortKey="Sanudo Wilhelmy, S A" uniqKey="Sanudo Wilhelmy S">S. A. Sanudo-Wilhelmy</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Carlucci, A F" uniqKey="Carlucci A">A. F. Carlucci</name></author><author><name sortKey="Bowes, P M" uniqKey="Bowes P">P. M. Bowes</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Carlucci, A F" uniqKey="Carlucci A">A. F. Carlucci</name></author><author><name sortKey="Silbemagel, S B" uniqKey="Silbemagel S">S. B. Silbemagel</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Carlucci, A F" uniqKey="Carlucci A">A. F. Carlucci</name></author><author><name sortKey="Silbernagel, S P" uniqKey="Silbernagel S">S. P. Silbernagel</name></author><author><name sortKey="Mcnally, P M" uniqKey="Mcnally P">P. M. McNally</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Chester, R" uniqKey="Chester R">R. Chester</name></author><author><name sortKey="Nimmo, M" uniqKey="Nimmo M">M. Nimmo</name></author><author><name sortKey="Keyse, S" uniqKey="Keyse S">S. Keyse</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Croft, M T" uniqKey="Croft M">M. T. Croft</name></author><author><name sortKey="Lawrence, A D" uniqKey="Lawrence A">A. D. Lawrence</name></author><author><name sortKey="Raux Deery, E" uniqKey="Raux Deery E">E. Raux-Deery</name></author><author><name sortKey="Warren, M J" uniqKey="Warren M">M. J. Warren</name></author><author><name sortKey="Smith, A G" uniqKey="Smith A">A. G. Smith</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Croft, M T" uniqKey="Croft M">M. T. Croft</name></author><author><name sortKey="Warren, M J" uniqKey="Warren M">M. J. Warren</name></author><author><name sortKey="Smith, A G" uniqKey="Smith A">A. G. Smith</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Daisley, K W" uniqKey="Daisley K">K. W. Daisley</name></author><author><name sortKey="Fisher, L R" uniqKey="Fisher L">L. R. Fisher</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Del Giorgio, P" uniqKey="Del Giorgio P">P. del Giorgio</name></author><author><name sortKey="Bird, D F" uniqKey="Bird D">D. F. Bird</name></author><author><name sortKey="Prairie, Y T" uniqKey="Prairie Y">Y. T. Prairie</name></author><author><name sortKey="Planas, D" uniqKey="Planas D">D. Planas</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Droop, M M" uniqKey="Droop M">M. M. Droop</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Fiala, M" uniqKey="Fiala M">M. Fiala</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Fiala, M" uniqKey="Fiala M">M. Fiala</name></author><author><name sortKey="Oriol, L" uniqKey="Oriol L">L. Oriol</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Gasol, J M" uniqKey="Gasol J">J. M. Gasol</name></author><author><name sortKey="Del Giorgio, P A" uniqKey="Del Giorgio P">P. A. Del Giorgio</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Giovannoni, S J" uniqKey="Giovannoni S">S. J. Giovannoni</name></author><author><name sortKey="Tripp, H J" uniqKey="Tripp H">H. J. Tripp</name></author><author><name sortKey="Givan, S" uniqKey="Givan S">S. Givan</name></author><author><name sortKey="Podar, M" uniqKey="Podar M">M. Podar</name></author><author><name sortKey="Vergin, K L" uniqKey="Vergin K">K. L. Vergin</name></author><author><name sortKey="Baptista, D" uniqKey="Baptista D">D. Baptista</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Gobler, C J" uniqKey="Gobler C">C. J. Gobler</name></author><author><name sortKey="Norman, C" uniqKey="Norman C">C. Norman</name></author><author><name sortKey="Panzeca, C" uniqKey="Panzeca C">C. Panzeca</name></author><author><name sortKey="Taylor, G T" uniqKey="Taylor G">G. T. Taylor</name></author><author><name sortKey="Sa Udo Wilhelmy, S A" uniqKey="Sa Udo Wilhelmy S">S. A. Sañudo-Wilhelmy</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Guerzoni, S" uniqKey="Guerzoni S">S. Guerzoni</name></author><author><name sortKey="Chester, R" uniqKey="Chester R">R. Chester</name></author><author><name sortKey="Dulac, F" uniqKey="Dulac F">F. Dulac</name></author><author><name sortKey="Herut, B" uniqKey="Herut B">B. Herut</name></author><author><name sortKey="Loye Pilot, M D" uniqKey="Loye Pilot M">M. D. Loye-Pilot</name></author><author><name sortKey="Measures, C" uniqKey="Measures C">C. Measures</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Guieu, C" uniqKey="Guieu C">C. Guieu</name></author><author><name sortKey="Chester, R" uniqKey="Chester R">R. Chester</name></author><author><name sortKey="Nimmo, M" uniqKey="Nimmo M">M. Nimmo</name></author><author><name sortKey="Martin, J M" uniqKey="Martin J">J. M. Martin</name></author><author><name sortKey="Guerzoni, S" uniqKey="Guerzoni S">S. Guerzoni</name></author><author><name sortKey="Nicolas, E" uniqKey="Nicolas E">E. Nicolas</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Guillard, R R L" uniqKey="Guillard R">R. R. L. Guillard</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Heimburger, L E" uniqKey="Heimburger L">L. E. Heimbürger</name></author><author><name sortKey="Chiffoleau, J F" uniqKey="Chiffoleau J">J. F. Chiffoleau</name></author><author><name sortKey="Dufour, A" uniqKey="Dufour A">A. Dufour</name></author><author><name sortKey="Auger, D" uniqKey="Auger D">D. Auger</name></author><author><name sortKey="Rozuel, E" uniqKey="Rozuel E">E. Rozuel</name></author><author><name sortKey="Migon, C" uniqKey="Migon C">C. Migon</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Knauer, G A" uniqKey="Knauer G">G. A. Knauer</name></author><author><name sortKey="Martin, J H" uniqKey="Martin J">J. H. Martin</name></author><author><name sortKey="Gordon, R M" uniqKey="Gordon R">R. M. Gordon</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Koch, F" uniqKey="Koch F">F. Koch</name></author><author><name sortKey="Marcoval, A" uniqKey="Marcoval A">A. Marcoval</name></author><author><name sortKey="Panzeca, C" uniqKey="Panzeca C">C. Panzeca</name></author><author><name sortKey="Bruland, K W" uniqKey="Bruland K">K. W. Bruland</name></author><author><name sortKey="Sa Udo Wilhelmy, S A" uniqKey="Sa Udo Wilhelmy S">S. A. Sañudo-Wilhelmy</name></author><author><name sortKey="Gobler, C J" uniqKey="Gobler C">C. J. Gobler</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Krom, M D" uniqKey="Krom M">M. D. Krom</name></author><author><name sortKey="Kress, N" uniqKey="Kress N">N. Kress</name></author><author><name sortKey="Brenner, S" uniqKey="Brenner S">S. Brenner</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Lasternas, S" uniqKey="Lasternas S">S. Lasternas</name></author><author><name sortKey="Agusti, S" uniqKey="Agusti S">S. Agusti</name></author><author><name sortKey="Duarte, C M" uniqKey="Duarte C">C. M. Duarte</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Li, W K W" uniqKey="Li W">W. K. W. Li</name></author><author><name sortKey="Dickie, P M" uniqKey="Dickie P">P. M. Dickie</name></author><author><name sortKey="Irwin, B D" uniqKey="Irwin B">B. D. Irwin</name></author><author><name sortKey="Wood, A M" uniqKey="Wood A">A. M. Wood</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Martens, J H" uniqKey="Martens J">J. H. Martens</name></author><author><name sortKey="Barg, H" uniqKey="Barg H">H. Barg</name></author><author><name sortKey="Warren, M J" uniqKey="Warren M">M. J. Warren</name></author><author><name sortKey="Jahn, D" uniqKey="Jahn D">D. Jahn</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Martin, J L Y" uniqKey="Martin J">J. L. Y. Martin</name></author><author><name sortKey="Vacelet, E" uniqKey="Vacelet E">E. Vacelet</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Marty, J C" uniqKey="Marty J">J. C. Marty</name></author><author><name sortKey="Chiaverini, J" uniqKey="Chiaverini J">J. Chiaverini</name></author><author><name sortKey="Pizay, M D" uniqKey="Pizay M">M. D. Pizay</name></author><author><name sortKey="Avril, B" uniqKey="Avril B">B. Avril</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Mc Gill, D" uniqKey="Mc Gill D">D. Mc Gill</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Mella Flores, D" uniqKey="Mella Flores D">D. Mella-Flores</name></author><author><name sortKey="Mazard, S" uniqKey="Mazard S">S. Mazard</name></author><author><name sortKey="Humily, F" uniqKey="Humily F">F. Humily</name></author><author><name sortKey="Partensky, F" uniqKey="Partensky F">F. Partensky</name></author><author><name sortKey="Mahe, F" uniqKey="Mahe F">F. Mahé</name></author><author><name sortKey="Bariat, L" uniqKey="Bariat L">L. Bariat</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Menzel, D W" uniqKey="Menzel D">D. W. Menzel</name></author><author><name sortKey="Spaeth, J P" uniqKey="Spaeth J">J. P. Spaeth</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Moschopoulou, N" uniqKey="Moschopoulou N">N. Moschopoulou</name></author><author><name sortKey="Ignatiades, L" uniqKey="Ignatiades L">L. Ignatiades</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Moutin, T" uniqKey="Moutin T">T. Moutin</name></author><author><name sortKey="Van Wambeke, F" uniqKey="Van Wambeke F">F. Van Wambeke</name></author><author><name sortKey="Prieur, L" uniqKey="Prieur L">L. Prieur</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Okbamichael, M" uniqKey="Okbamichael M">M. Okbamichael</name></author><author><name sortKey="Sa Udo Wilhelmy, S A" uniqKey="Sa Udo Wilhelmy S">S. A. Sañudo-Wilhelmy</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Olson, R J" uniqKey="Olson R">R. J. Olson</name></author><author><name sortKey="Chisholm, S W" uniqKey="Chisholm S">S. W. Chisholm</name></author><author><name sortKey="Zettler, E R" uniqKey="Zettler E">E. R. Zettler</name></author><author><name sortKey="Armbrust, E V" uniqKey="Armbrust E">E. V. Armbrust</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Panzeca, C" uniqKey="Panzeca C">C. Panzeca</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Panzeca, C" uniqKey="Panzeca C">C. Panzeca</name></author><author><name sortKey="Beck, A J" uniqKey="Beck A">A. J. Beck</name></author><author><name sortKey="Leblanc, K" uniqKey="Leblanc K">K. Leblanc</name></author><author><name sortKey="Taylor, G T" uniqKey="Taylor G">G. T. Taylor</name></author><author><name sortKey="Hutchins, D A" uniqKey="Hutchins D">D. A. Hutchins</name></author><author><name sortKey="Sa Udo Wilhelmy, S A" uniqKey="Sa Udo Wilhelmy S">S. A. Sañudo-Wilhelmy</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Panzeca, C" uniqKey="Panzeca C">C. Panzeca</name></author><author><name sortKey="Beck, A J" uniqKey="Beck A">A. J. Beck</name></author><author><name sortKey="Tovar Sanchez, A" uniqKey="Tovar Sanchez A">A. Tovar-Sanchez</name></author><author><name sortKey="Segovia Zavala, J" uniqKey="Segovia Zavala J">J. Segovia-Zavala</name></author><author><name sortKey="Taylor, G" uniqKey="Taylor G">G. Taylor</name></author><author><name sortKey="Gobler, C J" uniqKey="Gobler C">C. J. Gobler</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Panzeca, C" uniqKey="Panzeca C">C. Panzeca</name></author><author><name sortKey="Tovar Sanchez, A" uniqKey="Tovar Sanchez A">A. Tovar-Sanchez</name></author><author><name sortKey="Agusti, S" uniqKey="Agusti S">S. Agustí</name></author><author><name sortKey="Reche, I" uniqKey="Reche I">I. Reche</name></author><author><name sortKey="Duarte, C M" uniqKey="Duarte C">C. M. Duarte</name></author><author><name sortKey="Taylor, G T" uniqKey="Taylor G">G. T. Taylor</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Parsons, T R" uniqKey="Parsons T">T. R. Parsons</name></author><author><name sortKey="Maita, Y" uniqKey="Maita Y">Y. Maita</name></author><author><name sortKey="Lalli, C M" uniqKey="Lalli C">C. M. Lalli</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Pinardi, N" uniqKey="Pinardi N">N. Pinardi</name></author><author><name sortKey="Masetti, E" uniqKey="Masetti E">E. Masetti</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Provasoli, L" uniqKey="Provasoli L">L. Provasoli</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Provasoli, L" uniqKey="Provasoli L">L. Provasoli</name></author><author><name sortKey="Carlucci, A F" uniqKey="Carlucci A">A. F. Carlucci</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Pulido Villena, E" uniqKey="Pulido Villena E">E. Pulido-Villena</name></author><author><name sortKey="Wagener, T" uniqKey="Wagener T">T. Wagener</name></author><author><name sortKey="Guieu, C" uniqKey="Guieu C">C. Guieu</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Raux, E" uniqKey="Raux E">E. Raux</name></author><author><name sortKey="Schubert, H L" uniqKey="Schubert H">H. L. Schubert</name></author><author><name sortKey="Warren, M L" uniqKey="Warren M">M. L. Warren</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Ridame, C" uniqKey="Ridame C">C. Ridame</name></author><author><name sortKey="Le Moal, M" uniqKey="Le Moal M">M. Le Moal</name></author><author><name sortKey="Guieu, C" uniqKey="Guieu C">C. Guieu</name></author><author><name sortKey="Ternon, E" uniqKey="Ternon E">E. Ternon</name></author><author><name sortKey="Biegala, I" uniqKey="Biegala I">I. Biegala</name></author><author><name sortKey="L Helguen, S" uniqKey="L Helguen S">S. L'Helguen</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Saito, M A" uniqKey="Saito M">M. A. Saito</name></author><author><name sortKey="Moffett, J W" uniqKey="Moffett J">J. W. Moffett</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Sa Udo Wilhelmy, S A" uniqKey="Sa Udo Wilhelmy S">S. A. Sañudo-Wilhelmy</name></author><author><name sortKey="Cutter, L" uniqKey="Cutter L">L. Cutter</name></author><author><name sortKey="Durazo, R" uniqKey="Durazo R">R. Durazo</name></author><author><name sortKey="Smail, E" uniqKey="Smail E">E. Smail</name></author><author><name sortKey="Gomez Consarnau, L" uniqKey="Gomez Consarnau L">L. Gomez-Consarnau</name></author><author><name sortKey="Webb, E A" uniqKey="Webb E">E. A. Webb</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Sa Udo Wilhelmy, S A" uniqKey="Sa Udo Wilhelmy S">S. A. Sañudo-Wilhelmy</name></author><author><name sortKey="Gobler, C J" uniqKey="Gobler C">C. J. Gobler</name></author><author><name sortKey="Okbamichael, M" uniqKey="Okbamichael M">M. Okbamichael</name></author><author><name sortKey="Taylor, G T" uniqKey="Taylor G">G. T. Taylor</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Simon, M" uniqKey="Simon M">M. Simon</name></author><author><name sortKey="Azam, F" uniqKey="Azam F">F. Azam</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Smith, D C" uniqKey="Smith D">D. C. Smith</name></author><author><name sortKey="Azam, F" uniqKey="Azam F">F. Azam</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Suarez Suarez, A" uniqKey="Suarez Suarez A">A. Suárez-Suárez</name></author><author><name sortKey="Tovar Sanchez, A" uniqKey="Tovar Sanchez A">A. Tovar-Sánchez</name></author><author><name sortKey="Rossell Mora, R" uniqKey="Rossell Mora R">R. Rosselló-Mora</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Tanaka, T" uniqKey="Tanaka T">T. Tanaka</name></author><author><name sortKey="Thingstad, T F" uniqKey="Thingstad T">T. F. Thingstad</name></author><author><name sortKey="Christaki, U" uniqKey="Christaki U">U. Christaki</name></author><author><name sortKey="Colombet, J" uniqKey="Colombet J">J. Colombet</name></author><author><name sortKey="Cornet Barthaux, V" uniqKey="Cornet Barthaux V">V. Cornet-Barthaux</name></author><author><name sortKey="Courties, C" uniqKey="Courties C">C. Courties</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Thingstad, T F" uniqKey="Thingstad T">T. F. Thingstad</name></author><author><name sortKey="Rassoulzadegan, F" uniqKey="Rassoulzadegan F">F. Rassoulzadegan</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Thur Czy, C E" uniqKey="Thur Czy C">C. E. Thuróczy</name></author><author><name sortKey="Boye, M" uniqKey="Boye M">M. Boye</name></author><author><name sortKey="Losno, R" uniqKey="Losno R">R. Losno</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Tovar Sanchez, A" uniqKey="Tovar Sanchez A">A. Tovar-Sánchez</name></author></analytic></biblStruct><biblStruct><analytic><author><name sortKey="Trousselier, M" uniqKey="Trousselier M">M. Trousselier</name></author><author><name sortKey="Courties, C" uniqKey="Courties C">C. Courties</name></author><author><name sortKey="Zettelmaier, S" uniqKey="Zettelmaier S">S. Zettelmaier</name></author></analytic></biblStruct></listBibl></div1></back></TEI><pmc article-type="research-article"><pmc-dir>properties open_access</pmc-dir>
<front><journal-meta><journal-id journal-id-type="nlm-ta">Front Microbiol</journal-id><journal-id journal-id-type="iso-abbrev">Front Microbiol</journal-id><journal-id journal-id-type="publisher-id">Front. Microbiol.</journal-id><journal-title-group><journal-title>Frontiers in Microbiology</journal-title></journal-title-group><issn pub-type="epub">1664-302X</issn><publisher><publisher-name>Frontiers Media S.A.</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="pmid">23772225</article-id><article-id pub-id-type="pmc">3677149</article-id><article-id pub-id-type="doi">10.3389/fmicb.2013.00126</article-id><article-categories><subj-group subj-group-type="heading"><subject>Microbiology</subject><subj-group><subject>Original Research Article</subject></subj-group></subj-group></article-categories><title-group><article-title>Geographical gradients of dissolved Vitamin B<sub>12</sub> in the Mediterranean Sea</article-title></title-group><contrib-group><contrib contrib-type="author"><name><surname>Bonnet</surname><given-names>S.</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref><xref ref-type="author-notes" rid="fn001"><sup>*</sup></xref></contrib><contrib contrib-type="author"><name><surname>Tovar-Sánchez</surname><given-names>A.</given-names></name><xref ref-type="aff" rid="aff2"><sup>2</sup></xref></contrib><contrib contrib-type="author"><name><surname>Panzeca</surname><given-names>C.</given-names></name><xref ref-type="aff" rid="aff3"><sup>3</sup></xref></contrib><contrib contrib-type="author"><name><surname>Duarte</surname><given-names>C. M.</given-names></name><xref ref-type="aff" rid="aff2"><sup>2</sup></xref><xref ref-type="aff" rid="aff4"><sup>4</sup></xref></contrib><contrib contrib-type="author"><name><surname>Ortega-Retuerta</surname><given-names>E.</given-names></name><xref ref-type="aff" rid="aff5"><sup>5</sup></xref></contrib><contrib contrib-type="author"><name><surname>Sañudo-Wilhelmy</surname><given-names>S. A.</given-names></name><xref ref-type="aff" rid="aff5"><sup>5</sup></xref></contrib></contrib-group><aff id="aff1"><sup>1</sup><institution>IRD, MIO, UM 110 - IRD Centre of Noumea, Aix-Marseille University, University of South Toulon Var, CNRS/INSU</institution><country>Noumea, New Caledonia, France</country></aff><aff id="aff2"><sup>2</sup><institution>Department of Global Change Research, IMEDEA (CSIC-UIB), Instituto Mediterráneo de Estudios Avanzados</institution><country>Esporles Balearic Islands, Spain</country></aff><aff id="aff3"><sup>3</sup><institution>Department of Biological Sciences, University of Southern California</institution><country>Los Angeles, CA, USA</country></aff><aff id="aff4"><sup>4</sup><institution>The UWA Oceans Institute, The University of Western Australia</institution><country>Crawley, WA, Australia</country></aff><aff id="aff5"><sup>5</sup><institution>Departament Biologia Marina i Oceanografia, Institut de Ciències del Mar, CSIC</institution><country>Barcelona, Spain</country></aff><author-notes><fn fn-type="edited-by"><p>Edited by: Laura Gomez-Consarnau, University of Southern California, USA</p></fn><fn fn-type="edited-by"><p>Reviewed by: Jennifer Macalady, Pennsylvania State University, USA; Gerhard J. Herndl, University of Vienna, Austria</p></fn><corresp id="fn001">*Correspondence: S. Bonnet, IRD Centre Nouméa, 101 Promenade Roger Laroque, BP A5 - 98848 Nouméa cedex, New Caledonia, France e-mail: <email xlink:type="simple">sophie.bonnet@univ-amu.fr</email></corresp><fn fn-type="other" id="fn002"><p>This article was submitted to Frontiers in Aquatic Microbiology, a specialty of Frontiers in Microbiology.</p></fn></author-notes><pub-date pub-type="epub"><day>10</day><month>6</month><year>2013</year></pub-date><pub-date pub-type="collection"><year>2013</year></pub-date><volume>4</volume><elocation-id>126</elocation-id><history><date date-type="received"><day>05</day><month>12</month><year>2012</year></date><date date-type="accepted"><day>02</day><month>5</month><year>2013</year></date></history><permissions><copyright-statement>Copyright © 2013 Bonnet, Tovar-Sánchez, Panzeca, Duarte, Ortega-Retuerta and Sañudo-Wilhelmy.</copyright-statement><copyright-year>2013</copyright-year><license license-type="open-access" xlink:href="http://creativecommons.org/licenses/by/3.0/"><license-p>This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.</license-p></license></permissions><abstract><p>Most eukaryotic phytoplankton require vitamin B<sub>12</sub> to grow. However, the cycling of this organic growth factor has received substantially less attention than other bioactive substances such as trace metals in the marine environment. This is especially true in the Mediterranean Sea, where direct measurements of dissolved vitamins have never been reported. We report here the first direct measurements of dissolved vitamin B<sub>12</sub> across longitudinal gradients in Mediterranean waters. The range of vitamin B<sub>12</sub> concentrations measured over the whole transect was 0.5–6.2 pM, which is slightly higher than the range (undetectable—4 pM) of ambient concentrations measured in other open ocean basins in the Pacific and Atlantic oceans. The concentrations measured in the western basin were significantly higher (<italic>p</italic> < 0.05) than those of the eastern basin. They were positively correlated with chlorophyll concentrations in the most western part of the basin, and did not show any significant correlation with any other biological variables in other regions of the sampling transect.</p></abstract><kwd-group><kwd>vitamin B<sub>12</sub></kwd><kwd>Mediterranean Sea</kwd><kwd>growth factor</kwd><kwd>phytoplankton</kwd><kwd>bacteria</kwd></kwd-group><counts><fig-count count="5"></fig-count><table-count count="1"></table-count><equation-count count="0"></equation-count><ref-count count="60"></ref-count><page-count count="10"></page-count><word-count count="6136"></word-count></counts></article-meta></front><body><sec id="s1"><title>Introduction</title><p>The Mediterranean Sea is an oligotrophic ecosystem (Mc Gill, <xref ref-type="bibr" rid="B31">1965</xref>; Krom et al., <xref ref-type="bibr" rid="B25">1991</xref>), with a west to east gradient of increasing oligotrophy. It is characterized by a strong thermal stratification with a sharp thermocline (10–20 m deep) during late spring to fall, and a mixing period in winter, leading to a phytoplankton bloom in the early Spring (e.g., Marty et al., <xref ref-type="bibr" rid="B30">2002</xref>; Moutin et al., <xref ref-type="bibr" rid="B35">2012</xref>).</p><p>Surface macro-nutrient concentrations also depend on the exchanges with the Atlantic Ocean (through the Strait of Gibraltar), the Black Sea (through the Bosphorus Strait and Marmara Sea), and depend on river discharge. In addition, the Mediterranean Sea receives the highest rate of aeolian dust deposition of the world's oceans (Guerzoni et al., <xref ref-type="bibr" rid="B19">1999</xref>) as well as anthropogenic aerosols from industrial and domestic activities from the highly populated areas around the basin (Chester et al., <xref ref-type="bibr" rid="B9">1996</xref>; Guieu et al., <xref ref-type="bibr" rid="B20">1997</xref>). Consequently, Mediterranean surface waters exhibit relatively high dissolved iron (Fe) concentrations that are linked to the dynamics of atmospheric deposition and water column stratification (Bonnet and Guieu, <xref ref-type="bibr" rid="B4">2006</xref>). Therefore, Fe availability rarely limits primary and prokaryotic heterotrophic production in those waters (Bonnet et al., <xref ref-type="bibr" rid="B5">2005</xref>; Pulido-Villena et al., <xref ref-type="bibr" rid="B45">2008</xref>). However, the elemental stoichiometry measured in different pools (i.e., particulate and dissolved, inorganic and organic) reveals a deficiency of phosphorus (P) relative to nitrogen (N) (Bethoux et al., <xref ref-type="bibr" rid="B3">2002</xref>), and phosphorus (P) availability has been seen to limit primary production, prokaryotic heterotrophic production and N<sub>2</sub> fixation along the Mediterranean basin (e.g., Thingstad and Rassoulzadegan, <xref ref-type="bibr" rid="B57">1995</xref>; Lasternas et al., <xref ref-type="bibr" rid="B26">2010</xref>; Ridame et al., <xref ref-type="bibr" rid="B47">2011</xref>).</p><p>Besides inorganic bioactive elements such as Fe and P, most eukaryotic phytoplankton require organic nutrients such as vitamin B<sub>12</sub> (Provasoli and Carlucci, <xref ref-type="bibr" rid="B44">1974</xref>; Droop, <xref ref-type="bibr" rid="B13">2007</xref>). Vitamin B<sub>12</sub> is a cobalt-containing organometallic compound involved in several vital enzymes in the central metabolism of algae (Raux et al., <xref ref-type="bibr" rid="B46">2000</xref>; Martens et al., <xref ref-type="bibr" rid="B28">2002</xref>). Many eukaryotic phytoplankton lack the biosynthetic pathway for vitamin B<sub>12</sub>. Croft et al. (<xref ref-type="bibr" rid="B10">2005</xref>, <xref ref-type="bibr" rid="B11">2006</xref>) recently showed that over 50% of the 326 algal species tested in culture collections were unable to grow without any vitamin B<sub>12</sub> additions, showing that they have an absolute requirement for this co-factor and thus depend on an exogenous pool. In the open and coastal ocean, the ambient pool may be insufficient to support maximum primary productivity as vitamin B<sub>12</sub> amendments have been shown to stimulate phytoplankton growth in the Atlantic, Pacific and Southern Ocean (Panzeca et al., <xref ref-type="bibr" rid="B40">2006</xref>; Sañudo-Wilhelmy et al., <xref ref-type="bibr" rid="B52">2006</xref>; Bertrand et al., <xref ref-type="bibr" rid="B2">2007</xref>; Gobler et al., <xref ref-type="bibr" rid="B18">2007</xref>; Koch et al., <xref ref-type="bibr" rid="B24">2011</xref>). The ambient pool of vitamin B<sub>12</sub> depends upon prokaryots (Archaea, Bacteria, Guillard, <xref ref-type="bibr" rid="B21">1968</xref>) as they possess the biosynthetic pathway to produce this vitamin, and eukaryotic algae would acquire vitamin B<sub>12</sub> either from symbiotic bacteria or directly from the dissolved pool (Provasoli, <xref ref-type="bibr" rid="B43">1963</xref>; Croft et al., <xref ref-type="bibr" rid="B10">2005</xref>; Droop, <xref ref-type="bibr" rid="B13">2007</xref>). Furthermore, vitamin concentrations have been linked to shifts in plankton community composition (Koch et al., <xref ref-type="bibr" rid="B24">2011</xref>). Recent laboratory studies also showed that ubiquitous picocyanobacteria, such as <italic>Synechococcus</italic> and unicellular diazotrophic cyanobacteria such as <italic>Crocosphaera</italic>, were also able to produce and release vitamin B<sub>12</sub>, with higher production rates compared to heterotrophic bacteria (Bonnet et al., <xref ref-type="bibr" rid="B6">2010</xref>).</p><p>Despite the recognized biogeochemical importance of vitamin B<sub>12</sub> in the Ocean, the cycling of this organic growth factor has received substantially less attention than other bioactive substances such as trace metals in the marine environment. This is especially true in the Mediterranean Sea, where direct measurements of dissolved vitamins have never been reported. Measuring vitamin B<sub>12</sub> concentrations in seawater represents a technical challenge, as this cofactor is found at picomolar (10<sup>−12</sup> M) levels in open ocean waters (e.g., Panzeca et al., <xref ref-type="bibr" rid="B38">2008</xref>, <xref ref-type="bibr" rid="B39">2009</xref>). The development of direct and efficient methods, in contrast to the indirect microbiological assays, to measure low levels of dissolved vitamin B<sub>12</sub> (Okbamichael and Sañudo-Wilhelmy, <xref ref-type="bibr" rid="B36">2004</xref>) now allows us to expand our knowledge on the biogeochemical cycling of this growth factor in the ocean (e.g., Panzeca et al., <xref ref-type="bibr" rid="B40">2006</xref>, <xref ref-type="bibr" rid="B38">2008</xref>, <xref ref-type="bibr" rid="B39">2009</xref>; Sañudo-Wilhelmy et al., <xref ref-type="bibr" rid="B52">2006</xref>, <xref ref-type="bibr" rid="B51">2012</xref>; Suárez-Suárez et al., <xref ref-type="bibr" rid="B55">2011</xref>).</p><p>In late spring 2007, we measured dissolved vitamin B<sub>12</sub> concentrations along a 3000 km west-east transect in the Mediterranean Sea (Figure <xref ref-type="fig" rid="F1">1</xref>), that exhibited nutrient and chlorophyll gradients, to characterize the vertical distribution of vitamin B<sub>12</sub> concentrations along with other relevant hydrological and biogeochemical factors.</p><fig id="F1" position="float"><label>Figure 1</label><caption><p><bold>Location of the thirteen stations of the cruise</bold>.</p></caption><graphic xlink:href="fmicb-04-00126-g0001"></graphic></fig></sec><sec sec-type="materials|methods" id="s2"><title>Materials and methods</title><p>Dissolved water samples for vitamin B<sub>12</sub> and other biological and chemical parameters were collected during May 2007 along a longitudinal transect in the Mediterranean Sea onboard the Spanish ship R/V Garcia del Cid. A total of 13 stations were sampled across a west-to-east transect (Figure <xref ref-type="fig" rid="F1">1</xref>), starting southwest of Sardinia and finishing in the Aegean Sea (Station 13). The cruise track also covered the eastern Mediterranean basin, near the Egyptian coast (Station 10).</p><sec><title>Hydrological and biogeochemical measurements</title><p>Vertical profiles of temperature and salinity were obtained using a Seabird 911 plus CTD. Seawater samples were collected at 6 depths between the surface and 200 m depth using 12 l Niskin bottles mounted on a rosette sampler.</p><p>Chlorophyll <italic>a</italic> (Chl <italic>a</italic>) concentrations were determined fluorometrically according to the method of Parsons et al. (<xref ref-type="bibr" rid="B41">1984</xref>). At each depth, 50 ml of seawater were filtered through 25 mm glass fiber filters (Whatman GF/F), extracted into 10 ml of 90% acetone for 24 h in the dark at 4°C. The fluorescence of the extracts was then measured on a calibrated Turner Designs fluorometer (Parsons et al., <xref ref-type="bibr" rid="B41">1984</xref>).</p><p>For inorganic nutrients (nitrate, phosphate, silicate), samples were collected in acid-washed 20 ml plastic flasks. Concentrations were determined using standard colorimetric techniques on a Bran Luebbe autoanalyser AA3. Detection limits for the procedures were 0.05 μM, 0.01 μM, and 0.1 μM for NO<sup>−</sup><sub>2</sub>+NO<sup>−</sup><sub>3</sub>, PO<sup>3−</sup><sub>4</sub> and Si(OH)<sub>4</sub>, respectively.</p></sec><sec><title>Vitamin B<sub>12</sub> concentration measurements</title><p>At each depth, 2 l of seawater were sampled for dissolved vitamin B<sub>12</sub> concentration determination. Briefly, immediately after collection, samples were acidified to pH 6 using 12 N trace metal grade HCl, transferred to sterile 2 l intravenous (IV) bags, and pumped through 5 g of Bondesil C18 resin (pre-conditioned with methanol) at a flow rate controlled at 1 ml min<sup>−1</sup>. Columns were then rinsed with 20 ml of MilliQ water and eluted with 5 ml HPLC grade methanol. The eluent was then evaporated under vacuum (Labconco Rapid-Vac), redissolved in 200 μ l of MilliQ water, and analyzed by High Performance Reverse Phase Liquid Chromatography (Shimadzu 10AD-vp) according to Okbamichael and Sañudo-Wilhelmy (<xref ref-type="bibr" rid="B36">2004</xref>). Samples were filtered again through 0.45 μm small-volume syringe filters (Millex®- FH) to further purify the sample before injection into the HPLC The method and filter type was tested using B<sub>12</sub> standard recovery (Panzeca, <xref ref-type="bibr" rid="B37a">2007</xref>).</p></sec><sec><title>Prokaryotic abundances (PA) and prokaryotic heterotrophic production (PHP) measurements</title><p>PA was determined by flow cytometry according to Trousselier et al. (<xref ref-type="bibr" rid="B59a">1995</xref>) after fixation of samples (4 ml) using a mixture of paraformaldehyde and glutaraldehyde (1%) and freezing in liquid nitrogen. Briefly, 200 μl of each sample was stained with 4 μl of 5 μmol l<sup>−1</sup> SYBR Green (Molecular Probes) for 10 minutes in the dark, and run through a FACS calibur™ flow cytometer (BD Biosciences) fitted with a laser emitting at 488 nm. Samples were run at a low flow rate and data were acquired in log mode until around 10,000 events were acquired. A stock solution (5 μl) of yellow–green 0.92 μm Polysciences latex beads was added as an internal standard per 200 μl of sample. The concentration of the fluorescent beads was calibrated every 2 days by direct microscope enumeration. Prokaryotic cells were detected by their signature in bivariate plots of side scatter (SSC) vs. green fluorescence (FL1). Data were gated and counted in the SSC vs. FL1 plot using the Paint-a-Gate software (del Giorgio et al., <xref ref-type="bibr" rid="B12">1996</xref>; Gasol and Del Giorgio, <xref ref-type="bibr" rid="B16">2000</xref>). PA was expressed in cells per liter.</p><p>PHP was estimated from 3H-leucine–protein synthesis following the microcentrifugation technique described in Smith and Azam (<xref ref-type="bibr" rid="B54">1992</xref>). Briefly, 5 μl of L-[4,5-3H] leucine were added to 1.5 ml samples, yielding a final concentration of 28.8 nM, and were incubated for 3 h. Incubations were stopped by addition of trichloroacetic acid (5% final concentration) and samples were stored at −20°C until processing at the home laboratory. We used a conversion factor from leucine to carbon incorporation of 1.5 kg C mol leu<sup>−1</sup> (Simon and Azam, <xref ref-type="bibr" rid="B53">1989</xref>).</p><p>Ocean Data View software was used for graphical presentation of all the data mentioned above. For constructing of the charts, one of the ODV interpolation methods—VG Gridding (X and Y scale length: 150) was used.</p></sec><sec><title>Statistics</title><p>Vitamin B<sub>12</sub> concentrations in the eastern and western basins were compared using a 2-tailed non parametric mean comparison test (<italic>n</italic> = 3, α = 0.05, unpaired samples). Surface (0–100 m) and deep (100–200 m) vitamin B<sub>12</sub> concentrations were compared using a 2-tailed non parametric mean comparison test (<italic>n</italic> = 3, α = 0.05, paired samples). To examine the relationship between vitamin B<sub>12</sub> concentrations, PA, PHP, and Chl <italic>a</italic> concentrations, Pearson's correlation coefficients were calculated and tested between each variable of interest (degree of freedom = <italic>n</italic> − 2, α = 0.05).</p></sec></sec><sec sec-type="results" id="s3"><title>Results</title><sec><title>Hydrological and biogeochemical background conditions</title><p>Temperature ranged from 15.95–20.24°C across the Mediterranean basin over the first 200 m (Figure <xref ref-type="fig" rid="F2">2A</xref>). These figures show the occurrence of thermal stratification along the whole transect, but with a shallower thermocline depth in the western basin (around 40 m depth) compared to the eastern basin (50–200 m depth). There was also a strong horizontal salinity gradient from west to east with a marked halocline in the Ionian Sea (stations 5 and 6) (Figures <xref ref-type="fig" rid="F1">1</xref>, <xref ref-type="fig" rid="F2">2B</xref>). This gradient separates western Atlantic waters entering the Mediterranean Sea through the Strait of Gibraltar, from the high salinity waters of the eastern Mediterranean Sea. Salinity was lower on the western side of the transect (down to 37 in surface waters), and gradually increased eastwards to reach up to 39 in the top 200 meters.</p><fig id="F2" position="float"><label>Figure 2</label><caption><p><bold>Horizontal and vertical distribution of <bold>(A)</bold> temperature, <bold>(B)</bold> salinity, <bold>(C)</bold> NOx concentrations, <bold>(D)</bold> PO<sub>4</sub> concentrations and <bold>(E)</bold> Silicate concentrations along the transect with station numbers (1–13) and sampling depths indicated by dots during cruise</bold>.</p></caption><graphic xlink:href="fmicb-04-00126-g0002"></graphic></fig><p>Surface waters were depleted in nutrients (Figures <xref ref-type="fig" rid="F2">2C–E</xref>). NO<sup>−</sup><sub>2</sub> + NO<sup>−</sup><sub>3</sub> (hereafter NO<sub>x</sub>) concentrations were low (around 0.1 μM) along the whole transect. The thickness of this depleted layer increased towards the east from about 50–80 m in the western part of the transect to more than 180 m in the eastern basin. Phosphate concentrations followed the same geographical trend as NO<sub>x</sub>, with surface concentrations close to the detection limit of conventional micromolar methods (0.01 μM), and a progressive deepening of the phosphacline going eastward. Surface phosphate concentrations increased in the Aegean Sea (stations 12 and 13) to reach around 0.06–0.07 μM. The NO<sub>x</sub>:PO<sub>4</sub> molar ratio was 21 over the whole cruise suggesting that the Mediterranean was potentially phosphate limited with respect to nitrate during our sampling campaign.</p><p>Silicate concentrations decreased from west to east to reach up to 0.18 μM in the eastern basin (Figure <xref ref-type="fig" rid="F2">2E</xref>), and increased again to 0.5 μM in surface waters of the Aegean Sea (stations 12 and 13). As seen with NO<sub>x</sub> and PO<sub>4</sub>, the depth of the silicacline deepened in the east (Figures <xref ref-type="fig" rid="F2">2C–E</xref>). The average stoechiometric Si:NO<sub>x</sub> molar ratio was 2.5 over the whole transect, which suggested that silicate was in sufficient supply relative to nitrate.</p><p>Chl <italic>a</italic> concentrations (Figure <xref ref-type="fig" rid="F3">3A</xref>) ranged from 0.02 to 1.6 μg l<sup>−1</sup> over the 0–200 m layer of the studied transect. The whole section was characterized by a deepening of the Deep Chlorophyll Maximum (DCM) from west (40–80 m) to east (80–125 m), associated with the increasing oligotrophy. Chl <italic>a</italic> concentrations in the DCM also decreased eastward. In the last 2 stations of the transect located in the Aegean Sea (stations 12 and 13), Chl <italic>a</italic> concentrations increased to 0.97 μg Chl <italic>a</italic> l<sup>−1</sup> in the DCM, and the depth of the DCM was shallower (around 60 m) as in the western side of the Mediterranean.</p><fig id="F3" position="float"><label>Figure 3</label><caption><p><bold>Horizontal and vertical distribution of <bold>(A)</bold> Vitamin B<sub>12</sub> concentrations, <bold>(B)</bold> Chlorophyll <italic>a</italic> concentrations, <bold>(C)</bold> Prokaryotic abundances (PA) and <bold>(D)</bold> Prokaryotic heterotrophic production (</bold> .</p></caption><graphic xlink:href="fmicb-04-00126-g0003"></graphic></fig></sec><sec><title>Vitamin B<sub>12</sub> concentrations</title><p>The range of vitamin B<sub>12</sub> concentrations (Figures <xref ref-type="fig" rid="F3">3B</xref>, <xref ref-type="fig" rid="F4">4</xref>) measured over the Mediterranean transect was 0.5–6.2 pM. A slight longitudinal gradient was present; the concentrations measured in the western basin (stations 1–6: 2.44 ± 1.64 pM; mean of all profiles from the western basin ± standard deviation) were significantly higher (<italic>p</italic> < 0.05) than those of the eastern basin (stations 7–13: 1.67 ± 0.92 pM) (2-tailed non parametric mean comparison test). Maximum values were reached at 40 m depth at station 3 (6.15 pM) and in surface at station 5 (6.20 pM). Most vertical profiles exhibited maximum vitamin B<sub>12</sub> concentrations close to the DCM (Figure <xref ref-type="fig" rid="F4">4</xref>), except at station 5. Other B<sub>12</sub> depth profiles were more homogeneous vertically (Stations 7 and 10). The two stations where samples were collected at 1000 m (i.e., stations 5 and 7) exhibited concentrations of 1.19 and 2.7 pM at this depth, respectively.</p><fig id="F4" position="float"><label>Figure 4</label><caption><p><bold>Vertical profiles of vitamin B<sub>12</sub> (pM), Chl <italic>a</italic>, Prokaryotic abundances (PA) and Prokaryotic heterotrophic production (PHP)</bold>. Units for B<sub>12</sub> and Chl <italic>a</italic> concentrations, PA and PHP are pmol l<sup>−1</sup>, μg l<sup>−1</sup>, ×10<sup>8</sup> cells l<sup>−1</sup> and μg C m<sup>−3</sup> h<sup>−1</sup>, respectively. Note that profiles for stations where only two data points were available are not plotted as vertical profiles.</p></caption><graphic xlink:href="fmicb-04-00126-g0004"></graphic></fig></sec><sec><title>Prokaryotic abundances and production</title><p>Prokaryotic abundance (Figure <xref ref-type="fig" rid="F3">3C</xref>) declined markedly from west to east. Maximum abundances were measured at station 1 at 20-50 m depth with 12 × 10<sup>8</sup> cells l<sup>−1</sup>. The abundance maxima then decreased towards the east and was located deeper within the water column (around 75 m depth). Abundances increased again at the Aegean Sea at the end of the transect to reach concentrations around 11 × 10<sup>8</sup> cells l<sup>−1</sup> at station 12 at 50 m depth.</p><p>Prokaryotic heterotrophic production (Figure <xref ref-type="fig" rid="F3">3D</xref>) followed approximately the same trend observed for prokaryotic abundance with maximum rates measured at station 1 at 20–50 m depth (25–33 μg C m<sup>−3</sup> h<sup>−1</sup>); it then decreased toward the eastern basin to reach minimum rates at stations 10 and 11 (10–12 μg C m<sup>−3</sup> h<sup>−1</sup>), increasing again in the Aegean Sea, reaching up to 52 μg C m<sup>−3</sup> h<sup>−1</sup>.</p></sec></sec><sec sec-type="discussion" id="s4"><title>Discussion</title><p>The Mediterranean Sea displayed a large variety of hydrological conditions during the stratification period, covering a large range of trophic conditions from the oligotrophic western basin to the ultra-oligotrophic eastern basin (Figures <xref ref-type="fig" rid="F2">2</xref>, <xref ref-type="fig" rid="F3">3</xref>). The west-to-east gradient in hydrological and biogeochemical conditions encountered during our cruise (thermal stratification, nutrient depletion in surface waters and the deepening of the nutriclines and the DCM) are typical conditions for the Mediterranean Sea during the so-called stratification period (e.g., Moutin et al., <xref ref-type="bibr" rid="B35">2012</xref>).</p><p>Vitamin B<sub>12</sub> is known to be a labile organic molecule with a short half-life (days) in seawater (Carlucci et al., <xref ref-type="bibr" rid="B8">1969</xref>). Thus, elevated concentrations are generally associated with local production. Bacteria are the primary producers of this organic growth factor (Raux et al., <xref ref-type="bibr" rid="B46">2000</xref>; Martens et al., <xref ref-type="bibr" rid="B28">2002</xref>), but as soon as it is produced, it is consumed by eukaryotic phytoplankton and some ubiquitous heterotrophic bacteria lacking biosynthetic pathways for vitamin B<sub>12</sub> (Giovannoni et al., <xref ref-type="bibr" rid="B17">2005</xref>; Bertrand et al., <xref ref-type="bibr" rid="B2">2007</xref>). The relation between production and stocks is thus sometimes more complex. In this study, vitamin B<sub>12</sub> distributions do not show any significant correlation with spatial patterns observed for prokaryotic heterotrophic production and abundance (Figure <xref ref-type="fig" rid="F3">3</xref>, <italic>r</italic> = 0.04 and −0.04 respectively, <italic>p</italic> > 0.05), probably because vitamin B<sub>12</sub> stocks are the net result of vitamin production and consumption by micro-organisms.</p><p>The depth distributions of vitamin B<sub>12</sub> were correlated to the chlorophyll maximum in the western part of the transect (stations 1–3, <italic>r</italic> = 0.66, <italic>p</italic> < 0.05). This trend is contrary to what has been observed in some eutrophic coastal systems (Sañudo-Wilhelmy et al., <xref ref-type="bibr" rid="B52">2006</xref>) where chlorophyll stocks in the fraction >5 μm were inversely correlated with vitamin B<sub>12</sub> concentrations; these inverse distributions were interpreted as vitamin consumption by large size phytoplankton species in these coastal areas, as most large phytoplanktonic species are auxotrophic for vitamin B<sub>12</sub> (Croft et al., <xref ref-type="bibr" rid="B10">2005</xref>, <xref ref-type="bibr" rid="B11">2006</xref>). In the Mediterranean Sea, during the stratification period, large-size phytoplankton are scarce and the system is dominated by prokaryotic phytoplankton which are pico-cyanobacteria <italic>Synechococcus</italic> and <italic>Prochlorococcus</italic> (Marty et al., <xref ref-type="bibr" rid="B30">2002</xref>; Lasternas et al., <xref ref-type="bibr" rid="B26">2010</xref>). Contrary to eukarytotic phytoplankton who are B<sub>12</sub> consumers, recent studies indicate that <italic>Synechococcus</italic> is able to produce and excrete large amounts of vitamin B<sub>12</sub> (Bonnet et al., <xref ref-type="bibr" rid="B6">2010</xref>), and <italic>Prochlorococcus</italic> also possess the biosynthetic pathway for vitamin B<sub>12</sub> production. Cyanobacterial counts are not available for this study but recent studies indicate that they are maximum at the DCM in Mediterranean waters during the season studied (Mella-Flores et al., <xref ref-type="bibr" rid="B32">2011</xref>); vitamin B<sub>12</sub> production by these cyanobacteria may explain the large vitamin B<sub>12</sub> stocks measured at stations 2 and 3 in the DCM. It has to be noted that relatively high vitamin B<sub>12</sub> concentrations were also measured in surface waters above the DCM at stations 4 and 5. These concentrations may be attributed either to prokaryotic heterotrophic production, or to synthesis by small cyanobacteria located in surface waters. Recent studies have reported an unusual near surface <italic>Synechococcus</italic> abundance maximum close to the Sicily Strait (Mella-Flores et al., <xref ref-type="bibr" rid="B32">2011</xref>) during the stratification period in the Mediterranean Sea, which might explain high production rates of vitamin B<sub>12</sub>. This cyanobacterial maximum is unusual compared to other oligotrophic areas (Olson et al., <xref ref-type="bibr" rid="B37">1988</xref>; Li et al., <xref ref-type="bibr" rid="B27">1992</xref>) and has been attributed to surface nutrient enrichment by atmospheric dust deposition (Mella-Flores et al., <xref ref-type="bibr" rid="B32">2011</xref>). In fact, it has been shown that dust inputs cause an increase predominantly in the cyanobacteria in Mediterranean waters (Bonnet et al., <xref ref-type="bibr" rid="B5">2005</xref>). At stations 4 and 5, nutrient inputs could also be from land sources as those stations are located near the Sicilian coast and usually that region is less oligotrophic than the rest of the Mediterranean Sea (e.g., Moutin et al., <xref ref-type="bibr" rid="B35">2012</xref>). This hypothesis is consistent with the slight increase in phosphate concentrations observed in the present study (Figure <xref ref-type="fig" rid="F2">2</xref>).</p><p>Vitamin B<sub>12</sub> concentrations were lower in deeper waters (100–200 m) compared to surface and subsurface (0–100 m) waters (<italic>p</italic> < 0.05), except at stations 3, 5, and 6 where they reached 3.99, 3.99, and 3.51 pM, respectively at 200 m depth. Stations 5 and 6 are located close to the Sicily strait, which separates the Mediterranean eastern and western basins, leading to active and complex hydrodynamic features (Pinardi and Masetti, <xref ref-type="bibr" rid="B42">2000</xref>); we could hypothesize that vitamin B<sub>12</sub> has been upwelled from deeper waters, potentially explaining the maxima seen at those stations. The two stations for which data are available below 200 m (stations 5 and 7) show concentrations of 1.19 and 2.67 pM at 1000 m, which are not very high but the lack of data between 200 and 1000 m makes it difficult to interpret. The only report of deep vitamin B<sub>12</sub> concentrations (surface to 800 m depth) available (Sañudo-Wilhelmy et al., <xref ref-type="bibr" rid="B51">2012</xref>) indicate that maximal concentrations were found in the upper mesopelagic zone, around 300 m and surface maxima can be the result of vitamin transport by different water masses. In the Mediterranean Sea, future studies including a deeper vertical resolution are needed to better understand B<sub>12</sub> distributions.</p><p>Depth-averaged vitamin concentrations were significantly (<italic>p</italic> < 0.05) higher in the western basin (2.44 ± 1.64 pM) and decreased slightly going eastward towards more oligotrophic waters (1.67 ± 0.92 pM). This trend is consistent with the survey performed by Moschopoulou and Ignatiades (<xref ref-type="bibr" rid="B34">1993</xref>), who measured the seasonal and spatial distribution of vitamin B<sub>12</sub> in the Saronicos Gulf (Aegean Sea). They reported concentrations ranging between 0.8 and 5.8 pM, which are higher than those measured in the present study within the same area (1.39 ± 1.79 pM). However, those results were obtained indirectly using the microbiological assay method that may not accurately reflect ambient conditions, as they were also conducted in 0.45–0.8 μm filtered seawater that may have included B-vitamin–producing bacteria in the filtrate (Menzel and Spaeth, <xref ref-type="bibr" rid="B33">1962</xref>; Carlucci and Bowes, <xref ref-type="bibr" rid="B6a">1970</xref>). Despite the few vitamin B<sub>12</sub> data available in Mediterranean waters, the west-to-east gradient of B<sub>12</sub> observed in our study is consistent with previous studies. For example, Martin and Vacelet (<xref ref-type="bibr" rid="B29">1975</xref>) and Fiala (<xref ref-type="bibr" rid="B14">1982</xref>) reported higher values in the western basin (French coast) compared to those reported for the eastern basin by Moschopoulou and Ignatiades (<xref ref-type="bibr" rid="B34">1993</xref>).</p><p>The overall range of vitamin B<sub>12</sub> concentrations measured in the Mediterranean Sea in the present study (0.5–6.2 pM) are slightly higher than the range of ambient concentrations (undetectable—4 pM) measured in other open ocean locations in the world ocean (Table <xref ref-type="table" rid="T1">1</xref>). For example, vitamin B<sub>12</sub> concentrations at stations located off the coast of Baja California were undetectable for 100 s of kilometers (Sañudo-Wilhelmy et al., <xref ref-type="bibr" rid="B51">2012</xref>). In the Southern Ocean, the North Atlantic and the South Indian Ocean, vitamin B<sub>12</sub> concentrations ranged from 0.4 to 4 pM (Panzeca et al., <xref ref-type="bibr" rid="B39">2009</xref>), 0.1–2.5 pM (Panzeca et al., <xref ref-type="bibr" rid="B38">2008</xref>) and 0.1–3 pM (Fiala and Oriol, <xref ref-type="bibr" rid="B15">1984</xref>) respectively (Table <xref ref-type="table" rid="T1">1</xref>). The reasons for such relatively high B<sub>12</sub> concentrations in Mediterranean waters despite oligo- to ultra-oligotrophic conditions are unclear. We can hypothesize that vitamin B<sub>12</sub> accumulates in surface waters because the growth of the main consumers (eukaryotic phytoplankton) is limited by macronutrients (nitrate and phosphate, e.g., Lasternas et al., <xref ref-type="bibr" rid="B26">2010</xref>; Ridame et al., <xref ref-type="bibr" rid="B47">2011</xref>; Tanaka et al., <xref ref-type="bibr" rid="B56">2011</xref>) in this area. Another hypothesis is that the high cobalt concentrations in Mediterranean waters stimulate de novo synthesis of vitamin B<sub>12</sub> as cobalt is the central metal ion in the B<sub>12</sub> molecule (Raux et al., <xref ref-type="bibr" rid="B46">2000</xref>; Martens et al., <xref ref-type="bibr" rid="B28">2002</xref>). Panzeca et al. (<xref ref-type="bibr" rid="B38">2008</xref>, <xref ref-type="bibr" rid="B39">2009</xref>) have shown that the spatial distribution of vitamin B<sub>12</sub> in various coastal and open ocean waters followed the abundance of total dissolved cobalt. Surface dissolved cobalt concentrations measured in surface Mediterranean waters are high (45–291 pM, Figure <xref ref-type="fig" rid="F5">5</xref> and Heimbürger et al., <xref ref-type="bibr" rid="B22">2009</xref>) compared to those of the Atlantic (5–87 pM, Saito and Moffett, <xref ref-type="bibr" rid="B50">2002</xref>; Panzeca et al., <xref ref-type="bibr" rid="B38">2008</xref>) and the Pacific Ocean (30–105 pM, Knauer et al., <xref ref-type="bibr" rid="B23">1982</xref>). They have been attributed to the high atmospheric dust inputs (Heimbürger et al., <xref ref-type="bibr" rid="B22">2009</xref>) as cobalt is a crustal constituent of dust (1.8%) and is soluble in seawater (Thuróczy et al., <xref ref-type="bibr" rid="B58">2010</xref>). Future studies combining simultaneous analysis of dissolved cobalt and vitamin B<sub>12</sub> will be necessary to substantiate their possible relationship in Mediterranean waters.</p><table-wrap id="T1" position="float"><label>Table 1</label><caption><p><bold>Ranges of vitamin B<sub>12</sub> concentrations reported in different marine areas of the world</bold>.</p></caption><table frame="hsides" rules="groups"><thead><tr><th align="left" rowspan="1" colspan="1"><bold>Studied area<xref ref-type="table-fn" rid="TN1"><sup>*</sup></xref></bold></th><th align="left" rowspan="1" colspan="1"><bold>Range of vitamin B<sub>12</sub> concentrations (pmol l<sup>−1</sup>)</bold></th><th align="left" rowspan="1" colspan="1"><bold>References</bold></th></tr></thead><tbody><tr><td align="left" rowspan="1" colspan="1">Sargasso Sea</td><td align="left" rowspan="1" colspan="1">0–0.3</td><td align="left" rowspan="1" colspan="1">Menzel and Spaeth (<xref ref-type="bibr" rid="B33">1962</xref>)</td></tr><tr><td align="left" rowspan="1" colspan="1">San Pedro Basin, California, USA</td><td align="left" rowspan="1" colspan="1">0.2–1.8</td><td align="left" rowspan="1" colspan="1">Panzeca et al. (<xref ref-type="bibr" rid="B39">2009</xref>)</td></tr><tr><td align="left" rowspan="1" colspan="1">North Atlantic surface waters</td><td align="left" rowspan="1" colspan="1">0.1–2.5</td><td align="left" rowspan="1" colspan="1">Panzeca et al. (<xref ref-type="bibr" rid="B38">2008</xref>)</td></tr><tr><td align="left" rowspan="1" colspan="1">Northeast Pacific Ocean</td><td align="left" rowspan="1" colspan="1">0–2.7</td><td align="left" rowspan="1" colspan="1">Carlucci and Silbemagel (<xref ref-type="bibr" rid="B6b">1966</xref>)</td></tr><tr><td align="left" rowspan="1" colspan="1">Southern part of the Indian Ocean</td><td align="left" rowspan="1" colspan="1">0.1–3.0</td><td align="left" rowspan="1" colspan="1">Fiala and Oriol (<xref ref-type="bibr" rid="B15">1984</xref>)</td></tr><tr><td align="left" rowspan="1" colspan="1">Bay of Biscay</td><td align="left" rowspan="1" colspan="1">0.1–3.7</td><td align="left" rowspan="1" colspan="1">Daisley and Fisher (<xref ref-type="bibr" rid="B11a">1958</xref>)</td></tr><tr><td align="left" rowspan="1" colspan="1">Gerlache Strait, Southern Ocean</td><td align="left" rowspan="1" colspan="1">0.4–4</td><td align="left" rowspan="1" colspan="1">Panzeca et al. (<xref ref-type="bibr" rid="B39">2009</xref>)</td></tr><tr><td align="left" rowspan="1" colspan="1">Mediterranean Sea</td><td align="left" rowspan="1" colspan="1">0.5–6.2</td><td align="left" rowspan="1" colspan="1">This study</td></tr></tbody></table><table-wrap-foot><fn id="TN1"><label>*</label><p><italic>The studied areas are ranked by the high limit of reported vitamin B<sub>12</sub> concentration range</italic>.</p></fn></table-wrap-foot></table-wrap><fig id="F5" position="float"><label>Figure 5</label><caption><p><bold>Surface dissolved cobalt concentrations (pM) along the Mediterranean transect</bold>. Surface seawater (<0.22 μm) was collected during the cruise THRESHOLDS I (from June 5 to June 30, 2006; 35.6–41.9°N, 3.6–30.1°E) according to (Tovar-Sánchez, <xref ref-type="bibr" rid="B59">2012</xref>). Cobalt was pre-concentrated by the APDC/DDDC organic extraction method and analyzed by ICP-MS according to protocols described in (Tovar-Sánchez, <xref ref-type="bibr" rid="B59">2012</xref>).</p></caption><graphic xlink:href="fmicb-04-00126-g0005"></graphic></fig><p>This study reports the first direct measurements of dissolved vitamin B<sub>12</sub> concentrations across longitudinal and trophic gradients in Mediterranean waters. Because vitamin B<sub>12</sub> is an essential nutrient for most algal species (Croft et al., <xref ref-type="bibr" rid="B10">2005</xref>), the availability of this growth factor could play a significant role on phytoplankton successions and carbon export in Mediterranean waters. Whereas our study could not resolve the possibility of B<sub>12</sub> limitation in the Mediterranean, it did provide insights onto the possible mechanisms influencing the geographical distribution of vitamin B<sub>12</sub>. Future studies will need to address the factors, such as photochemical degradation, production, excretion, and uptake rates by microorganisms, responsible for the cycling of vitamin B<sub>12</sub> in Mediterranean waters.</p><sec><title>Conflict of interest statement</title><p>The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.</p></sec></sec></body><back><ack><p>This work was supported by the National Science Foundation (Chemical Oceanography Award OCE-0962209).</p></ack><ref-list><title>References</title><ref id="B2"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Bertrand</surname><given-names>E. M.</given-names></name><name><surname>Saito</surname><given-names>M. A.</given-names></name><name><surname>Rose</surname><given-names>J. M.</given-names></name><name><surname>Riesselman</surname><given-names>C. R.</given-names></name><name><surname>Lohan</surname><given-names>M. C.</given-names></name><name><surname>Noble</surname><given-names>A. E.</given-names></name><etal></etal></person-group> (<year>2007</year>). <article-title>Vitamin B12 and iron co-limitation of phytoplankton growth in the Ross Sea</article-title>. <source>Limnol. Oceanogr</source>. <volume>52</volume>, <fpage>1079</fpage>–<lpage>1093</lpage></mixed-citation></ref><ref id="B3"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Bethoux</surname><given-names>J. P.</given-names></name><name><surname>Morin</surname><given-names>P.</given-names></name><name><surname>Ruiz-Pino</surname><given-names>D. P.</given-names></name></person-group> (<year>2002</year>). <article-title>Temporal trends in nutrient ratios: chemical evidence of Mediterranean ecosystem changes driven by human activity</article-title>. <source>Deep Sea Res. Part II Top. Stud. Oceanogr</source>. <volume>49</volume>, <fpage>2007</fpage>–<lpage>2015</lpage></mixed-citation></ref><ref id="B4"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Bonnet</surname><given-names>S.</given-names></name><name><surname>Guieu</surname><given-names>C.</given-names></name></person-group> (<year>2006</year>). <article-title>Atmospheric forcing on the annual iron cycle in the Mediterranean Sea: a one-year survey</article-title>. <source>J. Geophys. Res</source>. <volume>111</volume>:<fpage>C09010</fpage><pub-id pub-id-type="doi">10.1029/2005JC003213</pub-id></mixed-citation></ref><ref id="B5"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Bonnet</surname><given-names>S.</given-names></name><name><surname>Guieu</surname><given-names>C.</given-names></name><name><surname>Chiaverini</surname><given-names>J.</given-names></name><name><surname>Ras</surname><given-names>J.</given-names></name><name><surname>Stock</surname><given-names>A.</given-names></name></person-group> (<year>2005</year>). <article-title>Impact of atmospheric inputs on the autotrophic communities in a low nutrient low chlorophyll system</article-title>. <source>Limnol. Oceanogr</source>. <volume>50</volume>, <fpage>1810</fpage>–<lpage>1819</lpage></mixed-citation></ref><ref id="B6"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Bonnet</surname><given-names>S.</given-names></name><name><surname>Webb</surname><given-names>E.</given-names></name><name><surname>Panzeca</surname><given-names>C.</given-names></name><name><surname>Karl</surname><given-names>D. M.</given-names></name><name><surname>Capone</surname><given-names>D. G.</given-names></name><name><surname>Sanudo-Wilhelmy</surname><given-names>S. A.</given-names></name></person-group> (<year>2010</year>). <article-title>Vitamin B<sub>12</sub> excretion by cultures of the marine cyanobacteria <italic>Crocosphaera</italic> and <italic>Synechococcus</italic></article-title>. <source>Limnol. Oceanogr</source>. <volume>55</volume>, <fpage>1959</fpage>–<lpage>1964</lpage></mixed-citation></ref><ref id="B6a"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Carlucci</surname><given-names>A. F.</given-names></name><name><surname>Bowes</surname><given-names>P. M.</given-names></name></person-group> (<year>1970</year>). <article-title>Production of vitamin B<sub>7</sub>, thiamine and biotin by phytoplankton</article-title>. <source>J. Phycol</source>. <volume>6</volume>, <fpage>351</fpage>–<lpage>357</lpage></mixed-citation></ref><ref id="B6b"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Carlucci</surname><given-names>A. F.</given-names></name><name><surname>Silbemagel</surname><given-names>S. B.</given-names></name></person-group> (<year>1966</year>). <article-title>Bioassay of seawater. III. Distribution of vitamin Bu in the North-East Pacific Ocean</article-title>. <source>Limnol. Oceanogr</source>. <fpage>642</fpage>–<lpage>646</lpage></mixed-citation></ref><ref id="B8"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Carlucci</surname><given-names>A. F.</given-names></name><name><surname>Silbernagel</surname><given-names>S. P.</given-names></name><name><surname>McNally</surname><given-names>P. M.</given-names></name></person-group> (<year>1969</year>). <article-title>Influence of temperature and solar radiation on the persistence of vitamin B<sub>12</sub>, thiamine, and biotin in seawater</article-title>. <source>J. Phycol</source>. <volume>5</volume>, <fpage>302</fpage>–<lpage>305</lpage></mixed-citation></ref><ref id="B9"><mixed-citation publication-type="book"><person-group person-group-type="author"><name><surname>Chester</surname><given-names>R.</given-names></name><name><surname>Nimmo</surname><given-names>M.</given-names></name><name><surname>Keyse</surname><given-names>S.</given-names></name></person-group> (<year>1996</year>). <article-title>The influence of Saharan and middle eastern desert-derived dust on the trace metal composition of Mediterranean aerosols and rainwaters: an overview</article-title>, in <source>The Impact of Desert Dust Across the Mediterranean</source>, eds <person-group person-group-type="editor"><name><surname>Guerzoni</surname><given-names>S.</given-names></name><name><surname>Chester</surname><given-names>R.</given-names></name></person-group> (<publisher-loc>Dordrecht</publisher-loc>: <publisher-name>Kluwer Academic Publisher</publisher-name>), <fpage>253</fpage>–<lpage>273</lpage></mixed-citation></ref><ref id="B10"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Croft</surname><given-names>M. T.</given-names></name><name><surname>Lawrence</surname><given-names>A. D.</given-names></name><name><surname>Raux-Deery</surname><given-names>E.</given-names></name><name><surname>Warren</surname><given-names>M. J.</given-names></name><name><surname>Smith</surname><given-names>A. G.</given-names></name></person-group> (<year>2005</year>). <article-title>Algae acquire vitamin B<sub>12</sub> through a symbiotic relationship with bacteria</article-title>. <source>Nature</source><volume>438</volume>, <fpage>90</fpage>–<lpage>93</lpage><pub-id pub-id-type="doi">10.1038/nature04056</pub-id><pub-id pub-id-type="pmid">16267554</pub-id></mixed-citation></ref><ref id="B11"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Croft</surname><given-names>M. T.</given-names></name><name><surname>Warren</surname><given-names>M. J.</given-names></name><name><surname>Smith</surname><given-names>A. G.</given-names></name></person-group> (<year>2006</year>). <article-title>Algae need their vitamins</article-title>. <source>Euk. Cell</source><volume>5</volume>, <fpage>1175</fpage>–<lpage>1183</lpage><pub-id pub-id-type="doi">10.1128/EC.00097-06</pub-id><pub-id pub-id-type="pmid">16896203</pub-id></mixed-citation></ref><ref id="B11a"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Daisley</surname><given-names>K. W.</given-names></name><name><surname>Fisher</surname><given-names>L. R.</given-names></name></person-group> (<year>1958</year>). <article-title>Vertical distribution of vitamin B<sub>12</sub> in the sea</article-title>. <source>J. Mar. Biol. Assoc. U.K</source>. <volume>37</volume>, <fpage>683</fpage>–<lpage>686</lpage><pub-id pub-id-type="doi">10.1017/S0025315400005725</pub-id></mixed-citation></ref><ref id="B12"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>del Giorgio</surname><given-names>P.</given-names></name><name><surname>Bird</surname><given-names>D. F.</given-names></name><name><surname>Prairie</surname><given-names>Y. T.</given-names></name><name><surname>Planas</surname><given-names>D.</given-names></name></person-group> (<year>1996</year>). <article-title>Flow cytometric determination of bacterial abundance in lake plankton with the green nucleic acid stain SYTO 13</article-title>. <source>Limnol. Oceanogr</source>. <volume>41</volume>, <fpage>783</fpage>–<lpage>789</lpage></mixed-citation></ref><ref id="B13"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Droop</surname><given-names>M. M.</given-names></name></person-group> (<year>2007</year>). <article-title>Vitamins, phytoplankton and bacteria: symbiosis or scavenging?</article-title><source>J. Plankton Res</source>. <volume>29</volume>, <fpage>107</fpage>–<lpage>113</lpage></mixed-citation></ref><ref id="B14"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Fiala</surname><given-names>M.</given-names></name></person-group> (<year>1982</year>). <article-title>Vitamine B<sub>12</sub> et phytoplancton au niveau de la thermocline en Méditerranée nord-occidentale</article-title>. <source>Oceanol. Acta</source><volume>5</volume>, <fpage>339</fpage>–<lpage>347</lpage></mixed-citation></ref><ref id="B15"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Fiala</surname><given-names>M.</given-names></name><name><surname>Oriol</surname><given-names>L.</given-names></name></person-group> (<year>1984</year>). <article-title>Vitamin B<sub>12</sub> and phytoplankton in the Antarctic Ocean: distribution and experimental approach</article-title>. <source>Mar. Biol</source>. <volume>79</volume><issue>Suppl.</issue>, <fpage>325</fpage>–<lpage>332</lpage></mixed-citation></ref><ref id="B16"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Gasol</surname><given-names>J. M.</given-names></name><name><surname>Del Giorgio</surname><given-names>P. A.</given-names></name></person-group> (<year>2000</year>). <article-title>Using flow cytometry for counting natural planktonic bacteria and understanding the structure of planktonic bacterial communities</article-title>. <source>Sci. Mar</source>. <volume>64</volume>, <fpage>197</fpage>–<lpage>224</lpage></mixed-citation></ref><ref id="B17"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Giovannoni</surname><given-names>S. J.</given-names></name><name><surname>Tripp</surname><given-names>H. J.</given-names></name><name><surname>Givan</surname><given-names>S.</given-names></name><name><surname>Podar</surname><given-names>M.</given-names></name><name><surname>Vergin</surname><given-names>K. L.</given-names></name><name><surname>Baptista</surname><given-names>D.</given-names></name><etal></etal></person-group> (<year>2005</year>). <article-title>Genome streamlining in a cosmopolitan oceanic bacterium</article-title>. <source>Science</source><volume>309</volume>, <fpage>1242</fpage><pub-id pub-id-type="doi">10.1126/science.1114057</pub-id><pub-id pub-id-type="pmid">16109880</pub-id></mixed-citation></ref><ref id="B18"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Gobler</surname><given-names>C. J.</given-names></name><name><surname>Norman</surname><given-names>C.</given-names></name><name><surname>Panzeca</surname><given-names>C.</given-names></name><name><surname>Taylor</surname><given-names>G. T.</given-names></name><name><surname>Sañudo-Wilhelmy</surname><given-names>S. A.</given-names></name></person-group> (<year>2007</year>). <article-title>Effect of B-vitamins (B<sub>1</sub>, B<sub>12</sub>) and inorganic nutrients on algal bloom dynamics in a coastal ecosystem</article-title>. <source>Aquat. Microb. Ecol</source>. <volume>49</volume>, <fpage>181</fpage>–<lpage>194</lpage></mixed-citation></ref><ref id="B19"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Guerzoni</surname><given-names>S.</given-names></name><name><surname>Chester</surname><given-names>R.</given-names></name><name><surname>Dulac</surname><given-names>F.</given-names></name><name><surname>Herut</surname><given-names>B.</given-names></name><name><surname>Loye-Pilot</surname><given-names>M. D.</given-names></name><name><surname>Measures</surname><given-names>C.</given-names></name><etal></etal></person-group> (<year>1999</year>). <article-title>The role of atmospheric deposition in the biogeochemistry of the Mediterranean Sea</article-title>. <source>Prog. Oceanogr</source>. <volume>44</volume>, <fpage>147</fpage>–<lpage>190</lpage></mixed-citation></ref><ref id="B20"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Guieu</surname><given-names>C.</given-names></name><name><surname>Chester</surname><given-names>R.</given-names></name><name><surname>Nimmo</surname><given-names>M.</given-names></name><name><surname>Martin</surname><given-names>J. M.</given-names></name><name><surname>Guerzoni</surname><given-names>S.</given-names></name><name><surname>Nicolas</surname><given-names>E.</given-names></name><etal></etal></person-group> (<year>1997</year>). <article-title>Atmospheric input of dissolved and particulate metals to the northwestern Mediterranean</article-title>. <source>Deep Sea Res. Part II Top. Stud. Oceanogr</source>. <volume>44</volume>, <fpage>655</fpage>–<lpage>674</lpage></mixed-citation></ref><ref id="B21"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Guillard</surname><given-names>R. R. L.</given-names></name></person-group> (<year>1968</year>). <article-title>B<sub>12</sub> specificity of marine centric diatoms</article-title>. <source>J. Physcol</source>. <volume>4</volume>, <fpage>59</fpage>–<lpage>64</lpage></mixed-citation></ref><ref id="B22"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Heimbürger</surname><given-names>L. E.</given-names></name><name><surname>Chiffoleau</surname><given-names>J. F.</given-names></name><name><surname>Dufour</surname><given-names>A.</given-names></name><name><surname>Auger</surname><given-names>D.</given-names></name><name><surname>Rozuel</surname><given-names>E.</given-names></name><name><surname>Migon</surname><given-names>C.</given-names></name><etal></etal></person-group> (<year>2009</year>). <article-title>Biogeochemical feedbacks in oligotrophic ocean water to atmospheric trace metal</article-title>, in <source>ASLO Aquatic Sciences Meeting 2009</source>, (Nice).</mixed-citation></ref><ref id="B23"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Knauer</surname><given-names>G. A.</given-names></name><name><surname>Martin</surname><given-names>J. H.</given-names></name><name><surname>Gordon</surname><given-names>R. M.</given-names></name></person-group> (<year>1982</year>). <article-title>Cobalt on Northeast Pacific waters</article-title>. <source>Nature</source><volume>297</volume>, <fpage>49</fpage>–<lpage>51</lpage></mixed-citation></ref><ref id="B24"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Koch</surname><given-names>F.</given-names></name><name><surname>Marcoval</surname><given-names>A.</given-names></name><name><surname>Panzeca</surname><given-names>C.</given-names></name><name><surname>Bruland</surname><given-names>K. W.</given-names></name><name><surname>Sañudo-Wilhelmy</surname><given-names>S. A.</given-names></name><name><surname>Gobler</surname><given-names>C. J.</given-names></name></person-group> (<year>2011</year>). <article-title>The effect of vitamin B<sub>12</sub>, nitrogen and iron on phytoplankton growth and community structure in the Gulf of Alaska</article-title>. <source>Limnol. Oceanogr</source>. <volume>56</volume>, <fpage>1023</fpage>–<lpage>1034</lpage></mixed-citation></ref><ref id="B25"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Krom</surname><given-names>M. D.</given-names></name><name><surname>Kress</surname><given-names>N.</given-names></name><name><surname>Brenner</surname><given-names>S.</given-names></name></person-group> (<year>1991</year>). <article-title>Phosphorus limitation of primary productivity in the eastern Mediterranean Sea</article-title>. <source>Limnol. Oceanogr</source>. <volume>36</volume>, <fpage>424</fpage>–<lpage>432</lpage></mixed-citation></ref><ref id="B26"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Lasternas</surname><given-names>S.</given-names></name><name><surname>Agusti</surname><given-names>S.</given-names></name><name><surname>Duarte</surname><given-names>C. M.</given-names></name></person-group> (<year>2010</year>). <article-title>Bacteria and phytoplankton abundance and viability across the Mediterranean Sea</article-title>. <source>Aquat. Microb. Ecol</source>. <volume>60</volume>, <fpage>175</fpage>–<lpage>191</lpage></mixed-citation></ref><ref id="B27"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Li</surname><given-names>W. K. W.</given-names></name><name><surname>Dickie</surname><given-names>P. M.</given-names></name><name><surname>Irwin</surname><given-names>B. D.</given-names></name><name><surname>Wood</surname><given-names>A. M.</given-names></name></person-group> (<year>1992</year>). <article-title>Biomass of bacteria, cyanobacteria, prochlorophytes and photosynthetic eukaryotes in the Sargasso Sea</article-title>. <source>Deep Sea Res. Part I</source><volume>39</volume>, <fpage>501</fpage>–<lpage>519</lpage></mixed-citation></ref><ref id="B28"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Martens</surname><given-names>J. H.</given-names></name><name><surname>Barg</surname><given-names>H.</given-names></name><name><surname>Warren</surname><given-names>M. J.</given-names></name><name><surname>Jahn</surname><given-names>D.</given-names></name></person-group> (<year>2002</year>). <article-title>Microbial production of vitamin B<sub>12</sub></article-title>. <source>Appl. Microbiol. Biotechnol</source>. <volume>58</volume>, <fpage>275</fpage>–<lpage>285</lpage><pub-id pub-id-type="doi">10.1007/s00253-001-0902-7</pub-id><pub-id pub-id-type="pmid">11935176</pub-id></mixed-citation></ref><ref id="B29"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Martin</surname><given-names>J. L. Y.</given-names></name><name><surname>Vacelet</surname><given-names>E.</given-names></name></person-group> (<year>1975</year>). <article-title>Le rôle des vitamines dans les relations bactéries-plancton. III. Relations entre la quantité de vitamines B<sub>12</sub> et les peuplements qui en font la synthèse</article-title>. <source>Cah. Biol. Mar</source>. <volume>16</volume>, <fpage>511</fpage>–<lpage>519</lpage></mixed-citation></ref><ref id="B30"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Marty</surname><given-names>J. C.</given-names></name><name><surname>Chiaverini</surname><given-names>J.</given-names></name><name><surname>Pizay</surname><given-names>M. D.</given-names></name><name><surname>Avril</surname><given-names>B.</given-names></name></person-group> (<year>2002</year>). <article-title>Seasonal and interannual dynamics of nutrients and phytoplankton pigments in the western Mediterranean Sea at the DYFAMED time-series station (1991–1999)</article-title>. <source>Deep Sea Res. Part II Top. Stud. Oceanogr</source>. <volume>49</volume>, <fpage>1965</fpage>–<lpage>1985</lpage></mixed-citation></ref><ref id="B31"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Mc Gill</surname><given-names>D.</given-names></name></person-group> (<year>1965</year>). <article-title>The relative supplies of phosphate, nitrate and silicate in the Mediterranean Sea</article-title>. <source>Rapports et Proces-Verbaux des Reunions Commission Internationale pour l'Exploration Scientifique de la Mer Mediterranee</source><volume>18</volume>, <fpage>734</fpage>–<lpage>744</lpage></mixed-citation></ref><ref id="B32"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Mella-Flores</surname><given-names>D.</given-names></name><name><surname>Mazard</surname><given-names>S.</given-names></name><name><surname>Humily</surname><given-names>F.</given-names></name><name><surname>Partensky</surname><given-names>F.</given-names></name><name><surname>Mahé</surname><given-names>F.</given-names></name><name><surname>Bariat</surname><given-names>L.</given-names></name><etal></etal></person-group> (<year>2011</year>). <article-title>Is the distribution of <italic>Prochlorococcus</italic> and <italic>Synechococcus</italic> ecotypes in the Mediterranean Sea affected by global warming?</article-title><source>Biogeosciences</source><volume>8</volume>, <fpage>2785</fpage>–<lpage>2804</lpage><pub-id pub-id-type="doi">10.5194/bg-8-2785-2011</pub-id></mixed-citation></ref><ref id="B33"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Menzel</surname><given-names>D. W.</given-names></name><name><surname>Spaeth</surname><given-names>J. P.</given-names></name></person-group> (<year>1962</year>). <article-title>Occurrence of vitamin B<sub>12</sub> in the Sargasso Sea</article-title>. <source>Limnol. Oceanogr</source>. <volume>7</volume>, <fpage>151</fpage>–<lpage>154</lpage></mixed-citation></ref><ref id="B34"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Moschopoulou</surname><given-names>N.</given-names></name><name><surname>Ignatiades</surname><given-names>L.</given-names></name></person-group> (<year>1993</year>). <article-title>Seasonal and spatial distribution of Vitamin B<sub>12</sub> in a Coastal area of eastern Mediterranean Sea</article-title>. <source>Int. Revue Ges. Hydrobiol</source>. <volume>78</volume>, <fpage>235</fpage>–<lpage>241</lpage></mixed-citation></ref><ref id="B35"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Moutin</surname><given-names>T.</given-names></name><name><surname>Van Wambeke</surname><given-names>F.</given-names></name><name><surname>Prieur</surname><given-names>L.</given-names></name></person-group> (<year>2012</year>). <article-title>Introduction to the Biogeochemistry from the Oligotrophic to the Ultraoligotrophic Mediterranean (BOUM) experiment</article-title>. <source>Biogeosciences</source><volume>9</volume>, <fpage>3817</fpage>–<lpage>3825</lpage></mixed-citation></ref><ref id="B36"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Okbamichael</surname><given-names>M.</given-names></name><name><surname>Sañudo-Wilhelmy</surname><given-names>S. A.</given-names></name></person-group> (<year>2004</year>). <article-title>New method for the determination of vitamin B<sub>12</sub> in seawater</article-title>. <source>Anal. Chim. Acta</source><volume>517</volume>, <fpage>33</fpage>–<lpage>38</lpage></mixed-citation></ref><ref id="B37"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Olson</surname><given-names>R. J.</given-names></name><name><surname>Chisholm</surname><given-names>S. W.</given-names></name><name><surname>Zettler</surname><given-names>E. R.</given-names></name><name><surname>Armbrust</surname><given-names>E. V.</given-names></name></person-group> (<year>1988</year>). <article-title>Analysis of <italic>Synechococcus</italic> pigment types in the sea using single and dual beam flow cytometry</article-title>. <source>Deep Sea Res. Part I</source><volume>35</volume>, <fpage>425</fpage>–<lpage>440</lpage></mixed-citation></ref><ref id="B37a"><mixed-citation publication-type="book"><person-group person-group-type="author"><name><surname>Panzeca</surname><given-names>C.</given-names></name></person-group> (<year>2007</year>). <source>B Vitamin Cycling in Coastal and Open Ocean Systems</source>. Ph.D thesis, <publisher-name>Stony Brook University</publisher-name>, <fpage>153</fpage></mixed-citation></ref><ref id="B38"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Panzeca</surname><given-names>C.</given-names></name><name><surname>Beck</surname><given-names>A. J.</given-names></name><name><surname>Leblanc</surname><given-names>K.</given-names></name><name><surname>Taylor</surname><given-names>G. T.</given-names></name><name><surname>Hutchins</surname><given-names>D. A.</given-names></name><name><surname>Sañudo-Wilhelmy</surname><given-names>S. A.</given-names></name></person-group> (<year>2008</year>). <article-title>Potential cobalt limitation of vitamin B<sub>12</sub> synthesis in the North Atlantic Ocean</article-title>. <source>Global Biogeochem. Cycles</source><volume>22</volume>:<fpage>GB2029</fpage><pub-id pub-id-type="doi">10.1029/2007GB003124</pub-id></mixed-citation></ref><ref id="B39"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Panzeca</surname><given-names>C.</given-names></name><name><surname>Beck</surname><given-names>A. J.</given-names></name><name><surname>Tovar-Sanchez</surname><given-names>A.</given-names></name><name><surname>Segovia-Zavala</surname><given-names>J.</given-names></name><name><surname>Taylor</surname><given-names>G.</given-names></name><name><surname>Gobler</surname><given-names>C. J.</given-names></name><etal></etal></person-group> (<year>2009</year>). <article-title>Distributions of dissolved vitamin B<sub>12</sub> and Co in coastal and open-ocean environments</article-title>. <source>Estuar. Coast. Shelf Sci</source>. <volume>85</volume>, <fpage>223</fpage>–<lpage>230</lpage></mixed-citation></ref><ref id="B40"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Panzeca</surname><given-names>C.</given-names></name><name><surname>Tovar-Sanchez</surname><given-names>A.</given-names></name><name><surname>Agustí</surname><given-names>S.</given-names></name><name><surname>Reche</surname><given-names>I.</given-names></name><name><surname>Duarte</surname><given-names>C. M.</given-names></name><name><surname>Taylor</surname><given-names>G. T.</given-names></name><etal></etal></person-group> (<year>2006</year>). <article-title>B Vitamins as regulators of phytoplankton dynamics</article-title>. <source>Eos Trans. AGU</source><volume>87</volume>, <fpage>593</fpage>–<lpage>596</lpage></mixed-citation></ref><ref id="B41"><mixed-citation publication-type="book"><person-group person-group-type="author"><name><surname>Parsons</surname><given-names>T. R.</given-names></name><name><surname>Maita</surname><given-names>Y.</given-names></name><name><surname>Lalli</surname><given-names>C. M.</given-names></name></person-group> (<year>1984</year>). <source>A Manual of Chemical and Biological Methods for Seawater Analysis</source>. <publisher-loc>Oxford</publisher-loc>: <publisher-name>Pergamon Press Ltd.</publisher-name></mixed-citation></ref><ref id="B42"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Pinardi</surname><given-names>N.</given-names></name><name><surname>Masetti</surname><given-names>E.</given-names></name></person-group> (<year>2000</year>). <article-title>Variability of the large scale general circulation of the Mediterranean Sea from observations and modelling: a review</article-title>. <source>Palaeogeogr. Palaeoclimatol</source>. <volume>158</volume>, <fpage>153</fpage>–<lpage>174</lpage><pub-id pub-id-type="doi">10.1016/S0031-0182(00)00048-1</pub-id></mixed-citation></ref><ref id="B43"><mixed-citation publication-type="book"><person-group person-group-type="author"><name><surname>Provasoli</surname><given-names>L.</given-names></name></person-group> (<year>1963</year>). <article-title>Organic regulation of phytoplankton fertility</article-title>, in <source>The Sea</source>, Vol. 2, ed <person-group person-group-type="editor"><name><surname>Hill</surname><given-names>M. N.</given-names></name></person-group> (<publisher-loc>New York, NY</publisher-loc>: <publisher-name>Interscience</publisher-name>), <fpage>165</fpage>–<lpage>219</lpage></mixed-citation></ref><ref id="B44"><mixed-citation publication-type="book"><person-group person-group-type="author"><name><surname>Provasoli</surname><given-names>L.</given-names></name><name><surname>Carlucci</surname><given-names>A. F.</given-names></name></person-group> (<year>1974</year>). <article-title>Vitamins and growth regulators</article-title>, in <source>Algal Physiology and Biochemistry</source>, ed <person-group person-group-type="editor"><name><surname>Stewart</surname><given-names>W. D. P.</given-names></name></person-group> (<publisher-loc>Malden, Mass</publisher-loc>: <publisher-name>Blackwell Science</publisher-name>), <fpage>741</fpage>–<lpage>787</lpage></mixed-citation></ref><ref id="B45"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Pulido-Villena</surname><given-names>E.</given-names></name><name><surname>Wagener</surname><given-names>T.</given-names></name><name><surname>Guieu</surname><given-names>C.</given-names></name></person-group> (<year>2008</year>). <article-title>Bacterial response to dust pulses in the western Mediterranean: implications for carbon cycling in the oligotrophic ocean</article-title>. <source>Global Biogeochem. Cycles</source><volume>22</volume>:<fpage>GB1020</fpage><pub-id pub-id-type="doi">10.1029/2007GB003091</pub-id></mixed-citation></ref><ref id="B46"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Raux</surname><given-names>E.</given-names></name><name><surname>Schubert</surname><given-names>H. L.</given-names></name><name><surname>Warren</surname><given-names>M. L.</given-names></name></person-group> (<year>2000</year>). <article-title>Biosynthesis of cobalamin (vitamin B<sub>12</sub>): a bacterial conundrum</article-title>. <source>Cell. Mol. Life Sci</source>. <volume>57</volume>, <fpage>1880</fpage>–<lpage>1893</lpage><pub-id pub-id-type="pmid">11215515</pub-id></mixed-citation></ref><ref id="B47"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Ridame</surname><given-names>C.</given-names></name><name><surname>Le Moal</surname><given-names>M.</given-names></name><name><surname>Guieu</surname><given-names>C.</given-names></name><name><surname>Ternon</surname><given-names>E.</given-names></name><name><surname>Biegala</surname><given-names>I.</given-names></name><name><surname>L'Helguen</surname><given-names>S.</given-names></name><etal></etal></person-group> (<year>2011</year>). <article-title>Nutrient control of N<sub>2</sub> fixation in the oligotrophic Mediterranean Sea and the impact of Saharan dust events</article-title>. <source>Biogeosciences</source><volume>8</volume>, <fpage>2773</fpage>–<lpage>2783</lpage></mixed-citation></ref><ref id="B50"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Saito</surname><given-names>M. A.</given-names></name><name><surname>Moffett</surname><given-names>J. W.</given-names></name></person-group> (<year>2002</year>). <article-title>Temporal and spatial variability of dissolved Co in the Atlantic Ocean</article-title>. <source>Geochim. Cosmochim. Acta</source><volume>66</volume>, <fpage>1943</fpage>–<lpage>1953</lpage></mixed-citation></ref><ref id="B51"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Sañudo-Wilhelmy</surname><given-names>S. A.</given-names></name><name><surname>Cutter</surname><given-names>L.</given-names></name><name><surname>Durazo</surname><given-names>R.</given-names></name><name><surname>Smail</surname><given-names>E.</given-names></name><name><surname>Gomez-Consarnau</surname><given-names>L.</given-names></name><name><surname>Webb</surname><given-names>E. A.</given-names></name><etal></etal></person-group> (<year>2012</year>). <article-title>Multiple B-vitamin depletion in large areas of the coastal ocean</article-title>. <source>Proc. Natl. Acad. Sci. U.S.A</source>. <volume>13</volume>, <fpage>14041</fpage>–<lpage>14045</lpage><pub-id pub-id-type="doi">10.1073/pnas.1208755109</pub-id><pub-id pub-id-type="pmid">22826241</pub-id></mixed-citation></ref><ref id="B52"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Sañudo-Wilhelmy</surname><given-names>S. A.</given-names></name><name><surname>Gobler</surname><given-names>C. J.</given-names></name><name><surname>Okbamichael</surname><given-names>M.</given-names></name><name><surname>Taylor</surname><given-names>G. T.</given-names></name></person-group> (<year>2006</year>). <article-title>Regulation of phytoplankton dynamics by vitamin B<sub>12</sub></article-title>. <source>Geophys. Res. Lett</source>. <volume>33</volume>:<fpage>L04604</fpage><pub-id pub-id-type="doi">10.1029/2005GL025046</pub-id></mixed-citation></ref><ref id="B53"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Simon</surname><given-names>M.</given-names></name><name><surname>Azam</surname><given-names>F.</given-names></name></person-group> (<year>1989</year>). <article-title>Protein content and protein synthesis rates of planktonic marine bacteria</article-title>. <source>Mar. Ecol. Prog. Ser</source>. <volume>51</volume>, <fpage>201</fpage>–<lpage>213</lpage><pub-id pub-id-type="doi">10.1128/AEM.67.11.5210-5218.2001</pub-id><pub-id pub-id-type="pmid">11679347</pub-id></mixed-citation></ref><ref id="B54"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Smith</surname><given-names>D. C.</given-names></name><name><surname>Azam</surname><given-names>F.</given-names></name></person-group> (<year>1992</year>). <article-title>A simple economical method for measuring bacterial protein synthesis rates in seawater using 3H leucine</article-title>. <source>Mar. Microb. Food Webs</source><volume>6</volume>, <fpage>107</fpage>–<lpage>114</lpage></mixed-citation></ref><ref id="B55"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Suárez-Suárez</surname><given-names>A.</given-names></name><name><surname>Tovar-Sánchez</surname><given-names>A.</given-names></name><name><surname>Rosselló-Mora</surname><given-names>R.</given-names></name></person-group> (<year>2011</year>). <article-title>Determination of cobalamins in seawater using reversed-phase liquid chromatography with diode-array detection</article-title>. <source>Anal. Chim. Acta</source><volume>701</volume>, <fpage>81</fpage>–<lpage>85</lpage><pub-id pub-id-type="doi">10.1016/j.aca.2011.04.040</pub-id><pub-id pub-id-type="pmid">21763812</pub-id></mixed-citation></ref><ref id="B56"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Tanaka</surname><given-names>T.</given-names></name><name><surname>Thingstad</surname><given-names>T. F.</given-names></name><name><surname>Christaki</surname><given-names>U.</given-names></name><name><surname>Colombet</surname><given-names>J.</given-names></name><name><surname>Cornet-Barthaux</surname><given-names>V.</given-names></name><name><surname>Courties</surname><given-names>C.</given-names></name><etal></etal></person-group> (<year>2011</year>). <article-title>Lack of P-limitation of phytoplankton and heterotrophic prokaryotes in surface waters of three anticyclonic eddies in the stratified Mediterranean Sea</article-title>. <source>Biogeosciences</source><volume>8</volume>, <fpage>525</fpage>–<lpage>538</lpage></mixed-citation></ref><ref id="B57"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Thingstad</surname><given-names>T. F.</given-names></name><name><surname>Rassoulzadegan</surname><given-names>F.</given-names></name></person-group> (<year>1995</year>). <article-title>Nutrient limitations, microbial food webs, and biological c-pumps: suggested interactions in a P-limited Mediterranean</article-title>. <source>Mar. Ecol. Prog. Ser</source>. <volume>117</volume>, <fpage>299</fpage>–<lpage>306</lpage></mixed-citation></ref><ref id="B58"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Thuróczy</surname><given-names>C. E.</given-names></name><name><surname>Boye</surname><given-names>M.</given-names></name><name><surname>Losno</surname><given-names>R.</given-names></name></person-group> (<year>2010</year>). <article-title>Dissolution of cobalt and zinc from natural and anthropogenic dusts in seawater</article-title>. <source>Biogeosciences</source><volume>7</volume>, <fpage>1927</fpage>–<lpage>1936</lpage></mixed-citation></ref><ref id="B59"><mixed-citation publication-type="book"><person-group person-group-type="author"><name><surname>Tovar-Sánchez</surname><given-names>A.</given-names></name></person-group> (<year>2012</year>). <article-title>Sampling approaches for trace elements determination in seawater</article-title>, in <source>Comprehensive Sampling and Sample Preparation</source>, ed <person-group person-group-type="editor"><name><surname>Pawliszyn</surname><given-names>J.</given-names></name></person-group> (<publisher-loc>Oxford</publisher-loc>: <publisher-name>Academic Press</publisher-name>), <fpage>317</fpage>–<lpage>334</lpage></mixed-citation></ref><ref id="B59a"><mixed-citation publication-type="journal"><person-group person-group-type="author"><name><surname>Trousselier</surname><given-names>M.</given-names></name><name><surname>Courties</surname><given-names>C.</given-names></name><name><surname>Zettelmaier</surname><given-names>S.</given-names></name></person-group> (<year>1995</year>). <article-title>Flow cytometric analysis of coastal lagoon bacterioplankton and picophytoplankton: fixation and storage effects</article-title>. <source>Estuarine Coast. Shelf Sci</source>. <volume>40</volume>, <fpage>621</fpage>–<lpage>633</lpage><pub-id pub-id-type="doi">10.1006/ecss.1995.0042</pub-id></mixed-citation></ref></ref-list></back></pmc></record>Pour manipuler ce document sous Unix (Dilib)
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