Publications: Peer-reviewed journal articles (by staff)

Trophic state and geographic gradients influence planktonic cyanobacterial diversity and cyanotoxin distribution

16 November, 2016
CITATION

Wood SA, Maier M, Puddick J, Pochon X, Dietrich DR, Hamilton DP 2016. Trophic state and geographic gradients influence planktonic cyanobacterial diversity and cyanotoxin distribution. FEMS Microbiology Ecology, vol 93(2):fiw234.

DOI link here

ABSTRACT

Cyanobacteria are commonly associated with eutrophic lakes, where they often form blooms and produce toxins. However they are a ubiquitous component of phytoplankton in lakes of widely varying trophic status. We hypothesised that cyanobacterial diversity would vary among lakes of differing trophic status, but that the relative importance of geographic and hydromorphological characteristics driving these patterns would differ across trophic groups. DNA from 143 New Zealand lakes that spanned a range of geographic, hydromorphological and trophic gradients was analysed using automated rRNA intergenic spacer analysis (ARISA) and screened for genes involved in cyanotoxin production. Statistical analysis revealed significant delineation among cyanobacterial communities from different trophic classes. Multivariate regression indicated that geographical features (latitude, longitude and altitude) were significant in driving cyanobacterial community structure, however partitioning of their effects varied among trophic categories. High-throughput sequencing (HTS) was undertaken on selected samples to investigate their taxonomic composition. The most abundant and diverse (71 operational taxonomic units) taxon across all lake types was the picocyanobacteria genus Synechococcus. Cyanotoxins (microcystins n = 23, anatoxins n = 1) were only detected in eutrophic lowland lakes. Collectively these data infer that increasing eutrophication of lakes will have broad-scale impacts on planktonic cyanobacteria diversity and the prevalence of cyanotoxins.