Microbial community diversity and composition varies with habitat characteristics and biofilm function in macrophyte‐rich streams

Abstract

Biofilms in streams play an integral role in ecosystem processes and function yet few studies have investigated the broad diversity of these complex prokaryotic and eukaryotic microbial communities. Physical habitat characteristics can affect the composition and abundance of microorganisms in these biofilms by creating microhabitats. Here we describe the prokaryotic and eukaryotic microbial diversity of biofilms in sand and macrophyte habitats (i.e. epipsammon and epiphyton, respectively) in five macrophyte‐rich streams in Jutland, Denmark. The macrophyte species varied in growth morphology, C:N stoichiometry, and preferred stream habitat, providing a range in environmental conditions for the epiphyton. Among all habitats and streams, the prokaryotic communities were dominated by common phyla, including Alphaproteobacteria, Bacteriodetes, and Gammaproteobacteria, while the eukaryotic communities were dominated by Stramenopiles (i.e. diatoms). For both the prokaryotes and eukaryotes, the epipsammon were consistently the most diverse communities and the epiphytic communities were generally similar among the four macrophyte species. However, the communities on the least complex macrophyte, Sparganium emersum, had the lowest richness and evenness and fewest unique OTUs, whereas the macrophyte with the most morphological complexity, Callitriche spp., had the highest number of unique OTUs. In general, the microbial taxa were ubiquitously distributed across the relatively homogeneous Danish landscape as determined by measuring the similarity among communities (i.e. Sørensen similarity index). Furthermore, we found significant correlations between microbial diversity (i.e. Chao1 rarefied richness and Pielou's evenness) and biofilm structure and function (i.e. C:N ratio and ammonium uptake efficiency, respectively); communities with higher richness and evenness had higher C:N ratios and lower uptake efficiency. In addition to describing the prokaryotic and eukaryotic community composition in stream biofilms, our study indicates that 1) physical habitat characteristics influence microbial diversity and 2) the variation in microbial diversity may dictate the structural and functional characteristics of stream biofilm communities.

Deciphering biodiversity and interactions between bacteria and microeukaryotes within epilithic biofilms from the Loue River, France

“…To our knowledge, only two works have simultaneously addressed both components (prokaryotes and eukaryotes) using high-throughput sequencing: Levi et al . 31 compared the composition of epipsammic and epiphytic biofilm communities across habitats with varying physical substrates and environmental conditions, and Bricheux et al . 15 characterized the microbial diversity of biofilms by testing different sets of primers on biofilms growing on glass substrates at one site in a French river.…”

Habitat species pools shape algal and bacterial communities and their correlations

“…For both ACC and BCC, the epipsammon (in sand) were consistently the most diverse communities and the epiphytic communities were generally similar among the four macrophyte species. Levi et al, 2017 Researches about correlations between ACC & BCC in a specific habitat In water column (in lakes) Variation trend of Shannon-Wiener diversity index in bacterioplankton community was similar to that of phytoplankton community. Temperature and phytoplankton played key roles in structuring BCC Niu et al, 2011 On the surface of algae (in lakes) Specific bacterial communities are associated with the dominant algae Shi et al, 2012 In water column (in lakes) Synchrony exists between phytoplankton and bacterioplankton community dynamics.…”

“…Besides, the inverse phylogenetic structural changes of algal and bacterial communities along chosen habitats in this article could also be explained in this way. As we know, higher community diversity implies a potential for greater multifunctionality (Finlay et al, 1997;Delgado-Baquerizo et al, 2016;Levi et al, 2017). For example, both one-time (Moriarty et al, 1985) and seasonal (Fischer and Pusch, 2001) reports have drawn a conclusion that sediment has the highest bacterial production among sediment, epiphyton and the planktonic zone of shallow waterbodies.…”

“…Thus, ACC, BCC, and their interactions are important parts of community ecology in littoral zones. There have been some reports about the differences of ACC/BCC between different habitats (Grossart et al, ; He et al, ; Fan et al, ; Pang et al, ; Levi et al, ) and the correlations between ACC and BCC in a specific habitat (Kent et al, ; Niu et al, ; Shi et al, ) (For precise description, see Table ). However, there is little information about the algal and bacterial community distributions and algae‐bacterial correlations based on habitat species pools.…”

Impact of Nutrient and Stoichiometry Gradients on Microbial Assemblages in Erhai Lake and Its Input Streams

“…Ecosystem metabolism is directly influenced by the relative balance of external loading of nutrients and dissolved organic carbon in lakes [13]. Stream ecosystems are primary receivers of nutrients and organic matter that export from terrestrial ecosystems through transport and storage of water, nutrients, and energy [14][15][16], and these nutrients and organic matter are transported by streams into lakes and marine environments [13]. In stream ecosystems, microbial assemblages primarily occur in the form of benthic biofilms [17], which play an important role in biogeochemical cycling, being responsible for organic matter mineralization, nutrient uptake, and transformation of contaminants [18].…”