Contrasting diversity of epibiotic bacteria and surrounding bacterioplankton of a common submerged macrophyte,Potamogeton crispus, in freshwater lakes

Abstract

Epibiotic bacteria on surfaces of submerged macrophytes play important roles in the ecological processes of shallow lakes. However, their community ecology and dynamics are far from understood in comparison with those of bacterioplankton. Here, we conducted a comparative study of the species diversity and composition of epibiotic bacterial and the surrounding bacterioplankton communities of a common submerged macrophyte, Potamogeton crispus, in 12 lakes at a regional scale in China. We found that in different freshwater lakes, epibiotic bacteria possessed higher taxonomic richness than bacterioplankton did. There existed a marked divergence in the community structure between epibiotic bacteria and bacterioplankton. Alphaproteobacteria was the most dominant group for epibiotic bacteria, whereas Actinobacteria dominated bacterioplankton. Although variations in both bacterioplankton and epibiotic bacterial community compositions in different lakes were better explained by environmental than spatial factors, both environment and space had more intensified effects on epibiotic bacteria. This implied more complex and diverse 'microhabitats' for epibiotic bacteria on surfaces of submerged macrophytes, which may lead to higher variations of epibiotic bacteria than bacterioplankton. Our study suggested that epibiotic bacteria exhibited higher diversity and distinct community composition than the surrounding bacterioplankton. More attention should be focused on the productive and diverse microbial habitats on submerged macrophytes.

Responses of bacterial community structure and denitrifying bacteria in biofilm to submerged macrophytes and nitrate

“…3 and Table S3). α-Proteobacteria was the most dominant group in biofilm from Potamogeton crispus in 12 freshwater lakes of China26, while β-Proteobacteria was the most abundant class on the leaves of two submerged macrophytes in Lake Taihu28. The percentages of unclassified or unknown species at the OTU level (Fig.…”

“…Proteobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Actinobacteria and Verrucomicrobia were the most abundantly represented phyla on the leaves of lettuce25 and Potamogeton crispus 26. Members of the Bacteroidetes phylum are abundant in aquatic habitats27.…”

pH Influences the Importance of Niche-Related and Neutral Processes in Lacustrine Bacterioplankton Assembly

“…Understanding the mechanisms governing bacterioplankton community assembly (e.g., community composition, diversity, and phylogenetic structure) in natural freshwater lakes is a longstanding challenge in microbial community ecology. There is increasing evidence that the community structure of freshwater lake bacterioplankton is influenced by niche-related (deterministic) and neutral (stochastic) processes (2)(3)(4). Niche-related processes (5) include selection imposed by the abiotic environment (environmental filtering) and species interactions (competition, facilitation, mutualism, and predation), whereas neutral effects (6) include stochastic processes, such as unpredictable disturbances, probabilistic dispersal, and random birth/death events (7,8).…”

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

“…Thirdly, the high richness and evenness of the epipsammic communities may have pattern in freshwater microbial communities (Besemer et al 2012). Variation in the abundance and composition of OTUs within the microbial communities was likely influenced by variation in spatial and environmental conditions as has been demonstrated in aquatic ecosystems (Heino et al 2010, He et al 2014, Lear et al 2014. For one, the epipsammic communities experienced a higher degree of resource heterogeneity within the microhabitats of the sand matrix than the epiphytic communities.…”

“…Much of our understanding on the interactions of biofilms and their environment comes from studies in marine and lentic ecosystems (reviewed by Wahl et al ), though environmental and/or spatial variation have been shown to dictate microbial diversity in stream ecosystems as well. For example, Acidobacteria dominated the composition of microbial communities in streams with low pH impacted by acid mine drainage, while more neutral streams had higher abundances of alpha‐, beta‐ and gammaproteobacteria (Fierer et al ), sub‐groups of a phylum that frequently dominates microbial communities in aquatic ecosystems (He et al ). In contrast, spatial variation influenced diatom diversity more strongly than habitat‐specific environmental variation across a broad geographic region (Heino et al ).…”