Rhythmicity of coastal marine picoeukaryotes, bacteria and archaea despite irregular environmental perturbations

Abstract

Seasonality in marine microorganisms has been classically observed in phytoplankton blooms, and more recently studied at the community level in prokaryotes, but rarely investigated at the scale of individual microbial taxa. Here we test if specific marine eukaryotic phytoplankton, bacterial and archaeal taxa display yearly rhythms at a coastal site impacted by irregular environmental perturbations. Our seven-year study in the Bay of Banyuls (North Western Mediterranean Sea) shows that despite some fluctuating environmental conditions, many microbial taxa displayed significant yearly rhythms. The robust rhythmicity was found in both autotrophs (picoeukaryotes and cyanobacteria) and heterotrophic prokaryotes. Sporadic meteorological events and irregular nutrient supplies did, however, trigger the appearance of less common non-rhythmic taxa. Among the environmental parameters that were measured, the main drivers of rhythmicity were temperature and day length. Seasonal autotrophs may thus be setting the pace for rhythmic heterotrophs. Similar environmental niches may be driving seasonality as well. The observed strong association between Micromonas and SAR11, which both need thiamine precursors for growth, could be a first indication that shared nutritional niches may explain some rhythmic patterns of cooccurrence.

Species detection and delineation in the marine planktonic diatoms Chaetoceros and Bacteriastrum through metabarcoding: making biological sense of haplotype diversity

“…The temporal distribution of reads reveals a regular progression of species through the seasonal cycle without clear definition of boundaries. Similar metabarcoding results have been reported recently at community level in bacteria, archea and picoeukaryotes (Gomez et al ., ; Lambert et al ., ).…”

Novel diversity within marine Mamiellophyceae (Chlorophyta) unveiled by metabarcoding

“…However since sampling was mostly in the Northern hemisphere, this has a low impact on the data interpretation. The existence of phytoplankton cycles driven by temporal changes and nutrient cycles in coastal environment 61–63 may explain why some species were not found in the OSD dataset in regions where strains or clones corresponding to the same species have been isolated before. As an example, Bathycoccus initially isolated from the Gulf of Naples in the Mediterranean Sea 23 was not recovered at the Naples OSD station (OSD4), where only 2 Mamiellophyceae reads were obtained.…”

Multifaceted aspects of synchrony between freshwater prokaryotes and protists

“…However, only multiyear studies can fully capture microbial variability linked to large‐scale environmental fluctuations (Shade et al, ). While several studies have investigated the temporal patterns of marine microbial communities (e.g., Lambert et al, ; Needham & Fuhrman, ), this is the first multiyear study that compares community dynamics of prokaryotes and protists in three environmentally distinct habitats in a lake ecosystem.…”

“…In fact, microbial communities often reflect changes in ecosystems (Thaler et al, ; Zohary, ). While Rusak et al () note that synchrony among microbes can be overridden by unusual climatic events such as high air temperature and enhanced mixing through wind, Lambert et al () note that microbes conserve their yearly patterns despite environmental fluctuations. Here, the timing of the response of prokaryotes and protists was not the same across habitats but was generally related to a gradient in precipitation.…”