Microbial communities reflect temporal changes in cyanobacterial composition in a shallow ephemeral freshwater lake

• Published in: The ISME Journal Vol. 10; no. 6; pp. 1337 - 1351
• Main Authors: Woodhouse, Jason Nicholas, Kinsela, Andrew Stephen, Collins, Richard Nicholas, Bowling, Lee Chester, Honeyman, Gordon L, Holliday, Jon K, Neilan, Brett Anthony
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.06.2016; Nature Publishing Group
• Subjects: 45/47; 45/77; 631/326/171/1878; 631/326/2565/855; Actinobacteria; Australia; Bacteria - classification; Bacteria - genetics; Bacteria - growth & development; Biodiversity; Biomedical and Life Sciences; Biotic factors; Climate Change; Community composition; Cyanobacteria; Cyanobacteria - classification; Cyanobacteria - genetics; Cyanobacteria - growth & development; Diversity indices; Ecology; Ephemeral lakes; Eutrophication; Evolutionary Biology; Fresh water; Fresh Water - microbiology; Freshwater lakes; Lakes - microbiology; Life Sciences; Microbial activity; Microbial Consortia; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Microcystis; Multivariate analysis; Nutrient cycles; Original; original-article; Oscillatoria; Planctomyces; Plankton - classification; Plankton - genetics; Plankton - growth & development; Seasons; Species Specificity; Verrucomicrobia; Water Microbiology; Waterways
• ISSN: 1751-7362; 1751-7370
• DOI: 10.1038/ismej.2015.218

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.