Biogeography and diversity of Collodaria (Radiolaria) in the global ocean.
Collodaria are heterotrophic marine protists that exist either as large colonies composed of hundreds of cells or as large solitary cells. All described species so far harbour intracellular microalgae as photosymbionts. Although recent environmental diversity surveys based on molecular methods demonstrated their consistently high contribution to planktonic communities and their worldwide occurrence, our understanding of their diversity and biogeography is still very limited. Here we estimated the 18S ribosomal DNA (rDNA) gene copies per collodarian cell for solitary (5770±1960 small subunit (SSU) rDNA copies) and colonial specimens (37 474±17 799 SSU rDNA copies, for each individual cell within a colony) using single-specimen quantitative PCR. We then investigated the environmental diversity of Collodaria within the photic zone through the metabarcoding survey from the Tara Oceans expedition and found that the two collodarian families Collosphaeridae and Sphaerozoidae contributed the most to the collodarian diversity and encompassed mostly cosmopolitan taxa. Although the biogeographical patterns were homogeneous within each biogeochemical biome considered, we observed that coastal biomes were consistently less diverse than oceanic biomes and were dominated by the Sphaerozoidae while the Collosphaeridae were dominant in the open oceans. The significant relationships with six environmental variables suggest that collodarian diversity is influenced by the trophic status of oceanic provinces and increased towards more oligotrophic regions.
Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire Adaptation et Diversité en Milieu Marin UMR7144, Station Biologique de Roscoff, Roscoff, France.|Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire d'Océanographie de Villefranche (LOV) UMR7093, Observatoire Océanologique, Villefranche-sur-Mer, France.
Tristan
T
Biard
Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire Adaptation et Diversité en Milieu Marin UMR7144, Station Biologique de Roscoff, Roscoff, France.
Estelle
E
Bigeard
Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire Adaptation et Diversité en Milieu Marin UMR7144, Station Biologique de Roscoff, Roscoff, France.
Stéphane
S
Audic
CEA-Institut de Génomique, GENOSCOPE, Evry, France.
Julie
J
Poulain
National Institute of Water and Atmospheric Research, Wellington, New Zealand.
Andres
A
Gutierrez-Rodriguez
PANGAEA, Data Publisher for Earth and Environmental Science, University of Bremen, Bremen, Germany.|MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
Stéphane
S
Pesant
Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire d'Océanographie de Villefranche (LOV) UMR7093, Observatoire Océanologique, Villefranche-sur-Mer, France.
Lars
0000-0001-8935-4531
L
Stemmann
Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire Adaptation et Diversité en Milieu Marin UMR7144, Station Biologique de Roscoff, Roscoff, France.
Fabrice
F
Not
D063147:Animal Distribution; D000818:Animals; D004275:DNA, Ribosomal / Q000235:genetics; D014644:Genetic Variation; D009792:Oceans and Seas; D010802:Phylogeny; D010933:Plankton; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D056901:Rhizaria / Q000235:genetics* / Q000502:physiology*
D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S