Seasonal temporal dynamics of marine protists communities in tidally mixed coastal waters
Résumé
Major seasonal community reorganizations and associated biomass variations are landmarks
of plankton ecology. However, the processes determining marine species and community
turnover rates have not been fully elucidated so far. Here, we analyse patterns of planktonic
protist community succession in temperate latitudes, based on quantitative taxonomic data
from both microscopy counts and ribosomal DNA metabarcoding from plankton samples
collected biweekly over 8 years (2009-2016) at the SOMLIT-Astan station (Roscoff, Western
English Channel). Considering the temporal structure of community dynamics (creating
temporal correlation), we elucidated the recurrent seasonal pattern of the dominant species
and OTUs (rDNA-derived taxa) that drive annual plankton successions. The use of
morphological and molecular analyses in combination allowed us to assess absolute species
abundance while improving taxonomic resolution, and revealed a greater diversity. Overall,
our results underpinned a protist community characterised by a seasonal structure, which is
supported by the dominant OTUs. We detected that some were partly benthic as a result of
the intense tidal mixing typical of the French coasts in the English Channel. While the
occurrence of these microorganisms is driven by the physical and biogeochemical conditions
of the environment, internal community processes, such as the complex network of biotic
interactions, also play a key role in shaping protist communities.
Domaines
Biodiversité et Ecologie| Origine | Fichiers produits par l'(les) auteur(s) |
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