Protist taxonomic and functional diversity in soil, freshwater and marine ecosystems

SEPPEY, C. ; BASS, D. ; DEBROAS, D.; DOMAIZON, I. ; KOENIG, I. ; MITCHELL, E.; SINGER D.; DUNTHORN, M.; BLANDENIER, Q. ; DE VARGAS, C.; IZAGUIRRE, I.; SCHIAFFINO, M.R.; LARA, E.; LENTENDU, G. ; BELBAHRI, L. ; DE GROOT, G.A.; DÚCKERT, C.; MATALONI, G.; GEISEN, S.

ENVIRONMENT INTERNATIONAL

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2021 vol. 146 p. 1 - 8

0160-4120

Protists dominate eukaryotic diversity and play key functional roles in all ecosystems, particularly by catalyzingcarbon and nutrient cycling. To date, however, a comparative analysis of their taxonomic and functional diversity that compares the major ecosystems on Earth (soil, freshwater and marine systems) is missing. Here, wepresent a comparison of protist diversity based on standardized high throughput 18S rRNA gene sequencing ofsoil, freshwater and marine environmental DNA. Soil and freshwater protist communities were more similar toeach other than to marine protist communities, with virtually no overlap of Operational Taxonomic Units (OTUs)between terrestrial and marine habitats. Soil protists showed higher γ diversity than aquatic samples. Differencesin taxonomic composition of the communities led to changes in a functional diversity among ecosystems, as expressed in relative abundance of consumers, phototrophs and parasites. Phototrophs (eukaryotic algae) dominated freshwater systems (49% of the reads) and consumers soil and marine ecosystems (59% and 48%, respectively). The individual functional groups were composed of ecosystem- specific taxonomic groups. Parasites wereequally common in all ecosystems, yet, terrestrial systems hosted more OTUs assigned to parasites of macro-organisms while aquatic systems contained mostly microbe parasitoids. Together, we show biogeographic patternsof protist diversity across major ecosystems on Earth, preparing the way for more focused studies that will helpunderstanding the multiple roles of protists in the biosphere.