Changes in Microbial (Bacteria and Archaea) Plankton Community Structure after Artificial Dispersal in Grazer-Free Microcosms

Abstract

Microbes are considered to have a global distribution due to their high dispersal capabilities. However, our knowledge of the way geographically distant microbial communities assemble after dispersal in a new environment is limited. In this study, we examined whether communities would converge because similar taxa would be selected under the same environmental conditions, or would diverge because of initial community composition, after artificial dispersal. To this aim, a microcosm experiment was performed, in which the temporal changes in the composition and diversity of different prokaryoplankton assemblages from three distant geographic coastal areas (Banyuls-sur-Mer in northwest Mediterranean Sea, Pagasitikos Gulf in northeast Mediterranean and Woods Hole, MA, USA in the northwest Atlantic), were studied. Diversity was investigated using amplicon pyrosequencing of the V1–V3 hypervariable regions of the 16S rRNA. The three assemblages were grown separately in particle free and autoclaved Banyuls-sur-mer seawater at 18 °C in the dark. We found that the variability of prokaryoplankton community diversity (expressed as richness, evenness and dominance) as well as the composition were driven by patterns observed in Bacteria. Regarding community composition, similarities were found between treatments at family level. However, at the OTU level microbial communities from the three different original locations diverge rather than converge during incubation. It is suggested that slight differences in the composition of the initial prokaryoplankton communities, resulted in separate clusters the following days even when growth took place under identical abiotic conditions.

Changes in Heterotrophic Picoplankton Community Structure after Induction of a Phytoplankton Bloom under Different Light Regimes

“…Other important bacterial families included were two that are well known from the marine environment, Flavobacteriaceae and Alteromonadaceae, which have also been found in previous Baltic Sea mesocosm experiments [29,56]. Flavobacteriaceae have been found to respond to enrichment in particulate or dissolved organic carbon [42]. However, in the current experiment their relative abundance increased only in the January treatments.…”

“…The decrease of unique OTUs during the course and/or towards the end of the growth phase in all mesocosms depicts that some kind of selection took place at the OTU level, resulting in an increase of dominance [42]. The most frequent and abundant OTUs (i.e., those found in all mesocosms and all sampling points), belonged to Rhodobacteraceae.…”

Diversity of Bacteria in Lakes with Different Chlorophyll Content and Investigation of Their Respiratory Activity through a Long-Term Microcosm Experiment

“…As mentioned above, we expect bacterial community structure in the experimental bottles to change during the experiment and we believe that low temporal fluctuations of respiratory rates in the microcosms reflect these changes. The succession pattern is associated not only with the environmental conditions that prevail in the bottles [e.g., available organic substrates, 61] but also to the initial bacterial assemblage [66]. Qualitative changes in bacterial community composition have also been shown previously in freshwater plankton respiration experiments [67] and this is probably a reason for the lack of correlation between respiration and bacterial abundance, size or growth [4].…”

Research on Imbalanced Microscopic Image Classification of Harmful Algae

“…Their circulation of materials which is characteristic of fast updating, short life cycle and high energy conversion efficiency plays a very important role in primary production control, energy flow, material circulation and regeneration of biogenic elements. As the most important biological group in marine ecological system, plankton community structure and diversity observation is of extremely important significance to marine ecological study, marine ecological disaster monitoring, ecosystem health evaluation and biological resource output [2,3].…”