Culturable diversity of Arctic phytoplankton during pack ice melting

• Published in: Elementa: Science of the Anthropocene
• Main Authors: Ribeiro, Catherine Gérikas, dos Santos, Adriana Lopes, Gourvil, Priscillia, Le Gall, Florence, Marie, Dominique, Tragin, Margot, Probert, Ian, Vaulot, Daniel
• Other Authors: Universidad Mayor de San Andrés (UMSA), ECOlogy of MArine Plankton (ECOMAP), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Nanyang Technological University Singapour, Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: Sympagic phytoplankton communities; Arctic diatoms; Arctic flagellates; Isolation techniques; 18S rRNA; Roscoff culture collection; envir; geo; Arctic; Baffin Bay; Baffin; Phytoplankton
• Online Access: https://doi.org/10.1525/elementa.401; https://hal.sorbonne-universite.fr/hal-02557111/file/401-6958-1-PB.pdf; https://hal.sorbonne-universite.fr/hal-02557111

International audience Massive phytoplankton blooms develop at the Arctic ice edge, sometimes extending far under the pack ice. An extensive culturing effort was conducted before and during a phytoplankton bloom in Baffin Bay between April and July 2016. Different isolation strategies were applied, including flow cytometry cell sorting, manual single cell pipetting, and serial dilution. Although all three techniques yielded the most common organisms, each technique retrieved specific taxa, highlighting the importance of using several methods to maximize the number and diversity of isolated strains. More than 1,000 cultures were obtained, characterized by 18S rRNA sequencing and optical microscopy, and de-replicated to a subset of 276 strains presented in this work. Strains grouped into 57 phylotypes defined by 100% 18S rRNA sequence similarity. These phylotypes spread across five divisions: Heterokontophyta, Chlorophyta, Cryptophyta, Haptophyta and Dinophyta. Diatoms were the most abundant group (193 strains), mostly represented by the genera Chaetoceros and Attheya. The genera Baffinella and Pyramimonas were the most abundant non-diatom nanoplankton strains, while Micromonas polaris dominated the picoplankton. Diversity at the class level was higher during the peak of the bloom. Potentially new species were isolated, in particular within the genera Navicula, Nitzschia, Coscinodiscus, Thalassiosira, Pyramimonas, Mantoniella and Isochrysis. Culturing efforts such as this one highlight the unexplored eukaryotic plankton diversity in the Arctic and provide a large number of strains for analyzing physiological and metabolic impacts in this changing environment.