title: 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.
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China; University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Dan
authors.initials: D
authors.lastname: He
authors.forename: Lijuan
authors.initials: L
authors.lastname: Ren
authors.forename: Qinglong L
authors.initials: QL
authors.lastname: Wu
mesh_terms: D039903:Actinobacteria / Q000145:classification* / Q000235:genetics; D020561:Alphaproteobacteria / Q000145:classification* / Q000235:genetics; D001483:Base Sequence; D044822:Biodiversity; D002681:China; D004269:DNA, Bacterial / Q000235:genetics; D060106:Lakes / Q000382:microbiology*; D059013:Microbial Consortia; D008969:Molecular Sequence Data; D010802:Phylogeny; D010839:Phytoplankton; D031821:Potamogetonaceae / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017423:Sequence Analysis, RNA
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: bacterioplankton; diversity pattern; epibiotic bacteria; submerged macrophyte