Diversity of cultured photosynthetic flagellates in the northeast Pacific and Arctic Oceans in summer

• Published in: Biogeosciences
• Main Authors: Balzano, Sergio, Gourvil, Priscillia, Siano, R., Chanoine, M., Marie, Dominique, Lessard, S., Sarno, D., Vaulot, Daniel
• Other Authors: Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff Roscoff (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Dynamiques de l'Environnement Côtier (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Diversité et Interactions au sein du Plancton Océanique (DIPO), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff Roscoff (SBR), Institut des Sciences de la MER de Rimouski (ISMER), Université du Québec à Rimouski (UQAR), Stazione Zoologica Anton Dohrn (SZN), JST-CNRS ``Phytometagene'', ASSEMBLE EU FP7, MACUMBA EU FP7, CPER Souchotheque de Bretagne, ANR MALINA ANR-08-BLAN-0308
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2012
• Subjects: envir; geo; Arctic; Bering Strait; Chukchi Sea; Pacific; Beaufort Sea; Chukchi; Phytoplankton
• Online Access: https://doi.org/10.5194/bg-9-4553-2012; https://hal.archives-ouvertes.fr/hal-01253998/file/bg-9-4553-2012.pdf; https://hal.archives-ouvertes.fr/hal-01253998

International audience During the MALINA cruise (summer 2009), an extensive effort was undertaken to isolate phytoplankton strains from the northeast (NE) Pacific Ocean, the Bering Strait, the Chukchi Sea, and the Beaufort Sea. In order to characterise the main photosynthetic microorganisms occurring in the Arctic during the summer season, strains were isolated by flow cytometry sorting (FCS) and single cell pipetting before or after phytoplankton enrichment of seawater samples. Strains were isolated both onboard and back in the laboratory and cultured at 4 degrees C under light/dark conditions. Overall, we isolated and characterised by light microscopy and 18 S rRNA gene sequencing 104 strains of photosynthetic flagellates which grouped into 21 genotypes (defined by 99.5% 18 S rRNA gene sequence similarity), mainly affiliated to Chlorophyta and Heterokontophyta. The taxon most frequently isolated was an Arctic ecotype of the green algal genus Micromonas (Arctic Micromonas), which was nearly the only phytoplankter recovered within the picoplankton (< 2 mu m) size range. Strains of Arctic Micromonas as well as other strains from the same class (Mamiellophyceae) were identified in further detail by sequencing the internal transcribed spacer (ITS) region of the rRNA operon. The MALINA Micromonas strains share identical 18 S rRNA and ITS sequences suggesting high genetic homogeneity within Arctic Micromonas. Three other Mamiellophyceae strains likely belong to a new genus. Other green algae from the genera Nephroselmis, Chlamydomonas, and Pyramimonas were also isolated, whereas Heterokontophyta included some unidentified Pelagophyceae, Dictyochophyceae (Pedinellales), and Chrysophyceae (Dinobryon faculiferum). Moreover, we isolated some Cryptophyceae (Rhodomonas sp.) as well as a few Prymnesiophyceae and dinoflagellates. We identified the dinoflagellate Woloszynskia cincta by scanning electron microscopy (SEM) and 28 S rRNA gene sequencing. Our morphological analyses show that this species possess the diagnostic ...