title: Microbial communities reflect temporal changes in cyanobacterial composition in a shallow ephemeral freshwater lake.
abstract: The frequency of freshwater cyanobacterial blooms is at risk of increasing as a consequence of climate change and eutrophication of waterways. It is increasingly apparent that abiotic data are insufficient to explain variability within the cyanobacterial community, with biotic factors such as heterotrophic bacterioplankton, viruses and protists emerging as critical drivers. During the Australian summer of 2012-2013, a bloom that occurred in a shallow ephemeral lake over a 6-month period was comprised of 22 distinct cyanobacteria, including Microcystis, Dolichospermum, Oscillatoria and Sphaerospermopsis. Cyanobacterial cell densities, bacterial community composition and abiotic parameters were assessed over this period. Alpha-diversity indices and multivariate analysis were successful at differentiating three distinct bloom phases and the contribution of abiotic parameters to each. Network analysis, assessing correlations between biotic and abiotic variables, reproduced these phases and assessed the relative importance of both abiotic and biotic factors. Variables possessing elevated betweeness centrality included temperature, sodium and operational taxonomic units belonging to the phyla Verrucomicrobia, Planctomyces, Bacteroidetes and Actinobacteria. Species-specific associations between cyanobacteria and bacterioplankton, including the free-living Actinobacteria acI, Bacteroidetes, Betaproteobacteria and Verrucomicrobia, were also identified. We concluded that changes in the abundance and nature of freshwater cyanobacteria are associated with changes in the diversity and composition of lake bacterioplankton. Given this, an increase in the frequency of cyanobacteria blooms has the potential to alter nutrient cycling and contribute to long-term functional perturbation of freshwater systems.
authors.affiliation: School of Biotechnology and Biomolecular Sciences, UNSW Australia, Sydney, New South Wales, Australia.
authors.forename: Jason Nicholas
authors.initials: JN
authors.lastname: Woodhouse
authors.affiliation: UNSW Water Research Centre and School of Civil and Environmental Engineering, UNSW Australia, Sydney, New South Wales, Australia.
authors.forename: Andrew Stephen
authors.initials: AS
authors.lastname: Kinsela
authors.affiliation: UNSW Water Research Centre and School of Civil and Environmental Engineering, UNSW Australia, Sydney, New South Wales, Australia.
authors.forename: Richard Nicholas
authors.initials: RN
authors.lastname: Collins
authors.affiliation: Office of Water, NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, New South Wales, Australia.|Centre for Ecosystem Science, UNSW Australia, Sydney, New South Wales, Australia.
authors.forename: Lee Chester
authors.initials: LC
authors.lastname: Bowling
authors.affiliation: Office of Water, NSW Department of Primary Industries, Hay, New South Wales, Australia.
authors.forename: Gordon L
authors.initials: GL
authors.lastname: Honeyman
authors.affiliation: Office of Water, NSW Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, New South Wales, Australia.
authors.forename: Jon K
authors.initials: JK
authors.lastname: Holliday
authors.affiliation: School of Biotechnology and Biomolecular Sciences, UNSW Australia, Sydney, New South Wales, Australia.
authors.forename: Brett Anthony
authors.initials: BA
authors.lastname: Neilan
mesh_terms: D001315:Australia; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development*; D044822:Biodiversity; D057231:Climate Change; D000458:Cyanobacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development*; D005068:Eutrophication; D005618:Fresh Water / Q000382:microbiology; D060106:Lakes / Q000382:microbiology; D059013:Microbial Consortia; D010933:Plankton / Q000145:classification* / Q000235:genetics / Q000254:growth & development; D012621:Seasons; D013045:Species Specificity; D014871:Water Microbiology