Surface ocean metabarcoding confirms limited diversity in planktonic foraminifera but reveals unknown hyper-abundant lineages

• Published in: Scientific Reports
• Main Authors: Morard, Raphael, Garet-Delmas, Marie-José, Mahé, Frédéric, Romac, Sarah, Poulain, Julie, Kucera, Michal, de Vargas, Colomban
• Other Authors: Center for Marine Environmental Sciences Bremen (MARUM), Universität Bremen, Adaptation et diversité en milieu marin (ADMM), Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff = Roscoff Marine Station (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DIVersité et COnnectivité dans le paysage marin côtier (DIVCO), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff = Roscoff Marine Station (SBR), Laboratoire des symbioses tropicales et méditerranéennes (UMR LSTM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université Montpellier 1 (UM1)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Evolution des Protistes et Ecosystèmes Pélagiques (EPEP), Genoscope - Centre national de séquençage Evry (GENOSCOPE), Université Paris-Saclay-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics; Phylogenetics and taxonomy; [SDV.MP.PRO]Life Sciences [q-bio]/Microbiology and Parasitology/Protistology; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; [SDE]Environmental Sciences; Indian; Planktonic foraminifera
• Online Access: https://hal.sorbonne-universite.fr/hal-01718031; https://hal.sorbonne-universite.fr/hal-01718031/document; https://hal.sorbonne-universite.fr/hal-01718031/file/s41598-018-20833-z.pdf; https://doi.org/10.1038/s41598-018-20833-z

International audience Since the advent of DNA metabarcoding surveys, the planktonic realm is considered a treasure trove of diversity, inhabited by a small number of abundant taxa, and a hugely diverse and taxonomically uncharacterized consortium of rare species. Here we assess if the apparent underestimation of plankton diversity applies universally. We target planktonic foraminifera, a group of protists whose known morphological diversity is limited, taxonomically resolved and linked to ribosomal DNA barcodes. We generated a pyrosequencing dataset of ~100,000 partial 18S rRNA foraminiferal sequences from 32 size fractioned photic-zone plankton samples collected at 8 stations in the Indian and Atlantic Oceans during the Tara Oceans expedition (2009–2012). We identified 69 genetic types belonging to 41 morphotaxa in our metabarcoding dataset. The diversity saturated at local and regional scale as well as in the three size fractions and the two depths sampled indicating that the diversity of foraminifera is modest and finite. The large majority of the newly discovered lineages occur in the small size fraction, neglected by classical taxonomy. These unknown lineages dominate the bulk [>0.8 µm] size fraction, implying that a considerable part of the planktonic foraminifera community biomass has its origin in unknown lineages.