Phylogenetic Differences in Attached and Free-Living Bacterial Communities in a Temperate Coastal Lagoon during Summer, Revealed via High-Throughput 16S rRNA Gene Sequencing

Abstract

bMost of what is known about coastal free-living and attached bacterial diversity is based on open coasts, with high particulate and nutrient riverine supply, terrestrial runoffs, and anthropogenic activities. The Magdalen Islands in the Gulf of St. Lawrence (Canada) are dominated by shallow lagoons with small, relatively pristine catchments and no freshwater input apart from rain. Such conditions provided an opportunity to investigate coastal free-living and attached marine bacterial diversity in the absence of confounding effects of steep freshwater gradients. We found significant differences between the two communities and marked temporal patterns in both. Taxonomic richness and diversity were greater in the attached than in the free-living community, increasing over summer, especially within the least abundant bacterial phyla. The highest number of reads fell within the SAR 11 clade (Pelagibacter, Alphaproteobacteria), which dominated free-living communities. The attached communities had deeper phylum-level diversity than the free-living fraction. Distance-based redundancy analysis indicated that the particulate organic matter (POM) concentration was the main variable separating early and late summer samples with salinity and temperature changes also significantly correlated to bacterial community structure. Our approach using high-throughput sequencing detected differences in free-living versus attached bacteria in the absence of riverine input, in keeping with the concept that marine attached communities are distinct from cooccurring free-living taxa. This diversity likely reflects the diverse microhabitats of available particles, implying that the total bacterial diversity in coastal systems is linked to particle supply and variability, with implications for understanding microbial biodiversity in marine systems.

Temporal and Vertical Variation in Microbial Community Composition in Response to Physicochemical Characteristics in a Water Column of Highly Eutrophied Jinhae Bay, South Korea

“…They demonstrated that temperature mostly drives vertical microbial community variation. Marked temporal patterns in bacterial community composition in a temperate coastal lagoon were also studied by high-throughput sequencing during early and late summer [Mohit et al, 2014]. These authors reported that temperature, salinity, and particulate organic matter are important determinants of the bacterial community structure.…”

“…These results reveal that changes in water conditions depending on the seasonal temperature change have a major influence on the microbial community composition. Some studies have shown a seasonal pattern of microbial communities by temperature [Pomeroy and Wiebe, 2001;Mohit et al, 2014;Sunagawa et al, 2015]. Sunagawa et al [2015] studied a marine microbial community structure and function on a global scale.…”

Microbial Surface Colonization and Biofilm Development in Marine Environments

“…The extracellular hydrolytic enzymes produced by surface-associated microbial assemblages usually have compositions and substrate ranges that differ from those of free-living microbial assemblages, likely due to differences in microbial composition (108,237,238). The elevated quantity and activity of surface-associated hydrolytic enzymes are likely influenced by the involvement of the QS regulatory mechanism in surface-associated microbial communities (239)(240)(241), and the higher enzyme specificity is likely due to the capability for sensing, recognition, and regulatory responses toward available substrates on the surface by specific surface-associated microorganisms (53, 242).…”

Dynamics of size-fractionated bacterial communities during the coastal dispersal of treated municipal effluents

“…Alphaproteobacteria, which consists of the SAR11 and SAR116 groups as well as Roseobacter, is the most common coastal bacterioplankton found in surface water (Sánchez et al 2007). A previous study showed that this subdivision of bacteria predominated in the FL population, whereas a relatively low abundance of Alphaproteobacteria was detected in the PA community (Mohit et al 2014). In contrast, other taxa that were more abundant in the FL population than in the PA population were divergent for the two sample series.…”