title: Warming and nutrient enrichment in combination increase stochasticity and beta diversity of bacterioplankton assemblages across freshwater mesocosms.
abstract: The current climate warming and eutrophication are known to interactively threaten freshwater biodiversity; however, the interactive effects on lacustrine bacterioplankton diversity remain to be determined. Here, we analyzed the spring bacterioplankton community composition (BCC) in 24 outdoor, flow-through mesocosms (mimicking shallow lake environments) under 3 temperature scenarios and 2 nutrient regimes. Our results revealed that neither long-term warming (8.5 years) nor nutrient enrichment had significant effects on bacterioplankton alpha diversity, whereas long-term enhanced warming (elevated 50% above the IPCC A2 climate scenario) and nutrient enrichment in combination increased bacterioplankton beta diversity. We also found that BCC shifted significantly under enhanced warming and nutrient-enriched conditions towards decreased relative abundances of Actinobacteria, Bacteroidetes and Betaproteobacteria, whereas the percentages of Cyanobacteria, total rare phyla and unclassified phyla significantly increased. Null-model tests indicated that deterministic processes played a more important role than stochastic processes in determining BCC. However, the relative importance of stochasticity, primarily ecological drift, was enhanced and contributed to the increased beta diversity of BCC under enhanced warming and nutrient-enriched conditions. Overall, our study suggests that the synergetic effects of warming and nutrient enrichment may result in high variability in the composition of bacterioplankton communities in lacustrine water bodies.
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.|Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Ren
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
authors.forename: Dan
authors.initials: D
authors.lastname: He
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Bioscience, Aarhus University, Silkeborg, Denmark.|Sino-Danish Centre for Education and Research, University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Erik
authors.initials: E
authors.lastname: Jeppesen
authors.affiliation: Department of Bioscience, Aarhus University, Silkeborg, Denmark.|Sino-Danish Centre for Education and Research, University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Torben L
authors.initials: TL
authors.lastname: Lauridsen
authors.affiliation: Department of Bioscience, Aarhus University, Silkeborg, Denmark.|Sino-Danish Centre for Education and Research, University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Martin
authors.initials: M
authors.lastname: Søndergaard
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.|Sino-Danish Centre for Education and Research, University of Chinese Academy of Sciences, Beijing, China.|Department of Ecology, Jinan University, Guangzhou, China.
authors.forename: Zhengwen
authors.initials: Z
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.|Sino-Danish Centre for Education and Research, University of Chinese Academy of Sciences, Beijing, China.|Department of Ecology, Jinan University, Guangzhou, China.
authors.forename: Qinglong L
authors.initials: QL
authors.lastname: Wu
mesh_terms: D039903:Actinobacteria / Q000145:classification* / Q000235:genetics / Q000502:physiology; D059001:Aquatic Organisms; D041963:Bacteroidetes / Q000145:classification* / Q000235:genetics / Q000502:physiology; D020562:Betaproteobacteria / Q000145:classification* / Q000235:genetics / Q000502:physiology; D044822:Biodiversity; D057231:Climate Change; D003718:Denmark; D017753:Ecosystem; D005068:Eutrophication; D060106:Lakes / Q000382:microbiology*; D010933:Plankton / Q000145:classification