Phytoplankton community structure in a high-nutrient, low-chlorophyll region of the eastern Pacific Subantarctic region during winter-mixed and summer-stratified conditions

• Main Authors: Bouman, Heather, Lep Ere, Cécile, J.Scanlan, David, Ulloa, Osvaldo
• Other Authors: Department of Earth Sciences Oxford, University of Oxford Oxford, Laboratoire Microorganismes : Génome et Environnement (LMGE), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université d'Auvergne - Clermont-Ferrand I (UdA)-Centre National de la Recherche Scientifique (CNRS), School ofLifeSciences,CoventryCV47AL, University of Warwick Coventry, Centro de Investigación Oceanográfica en el Pacífico Sur Oriental (COPAS), Universidad de Concepción Chile
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2012
• Subjects: Picophytoplankton Community structure Subantarctic Southern Ocean HNLC HPLC pigments Molecular probes; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Austral; Pacific; Southern Ocean
• Online Access: https://hal.archives-ouvertes.fr/hal-00848697

International audience PhytoplanktoncommunitystructurewasanalysedintheSubantarcticsectoroftheeasternSouth Pacific,ahigh-nutrient,low-chlorophyll(HNLC)region,duringaperiodofdeepverticalmixing(austral winterAug-Oct,2005)whenAntarcticIntermediateWater(AAIW)getsformed,andduringaperiodof water-columnstratificationcharacterisedbyshallowmixedlayers(australsummerFeb-Mar,2006). We examinedboththeentirephytoplanktonassemblagethroughtheuseofdiagnosticpigmentsand also thepicophytoplanktonfraction(o3 mm) throughtheuseofclass-specificmolecularprobesand flow cytometry.Boththepigmentandmoleculardatarevealadominanceofprymnesiophytesduringboth the winter-mixedandsummer-stratifiedperiods.Chrysophytesandtheirdiagnosticpigmentswerealso present throughoutmostofthestudyregion.Flowcytometricanalysisrevealedthatthecontributionof photosyntheticpicoeukaryotes(PPEs)tototalpicophytoplankton(PPEsþpicocyanobacteria)abundances increasessystematicallywithincreasinglatitudeanddecreasingtemperature,highlightingtheimportance of PPEsintheSouthernOcean