Community composition, toxigenicity, and environmental conditions during a Cyanobacterial Bloom occurring along 1,100 kilometers of the Murray River

Al-Tebrineh Jamal, Chester Merrick, David Ryan, Andrew Humpage, Lee Browning, Brett Neilan

    Research output: Contribution to journalArticle

    42 Citations (Scopus)

    Abstract

    A cyanobacterial bloom impacted over 1,100 km of the Murray River, Australia, and its tributaries in 2009. Physicochemical conditions in the river were optimal to support a bloom at the time. The data suggest that at least three blooms occurred concurrently in different sections of the river, with each having a different community composition and associated cyanotoxin profile. Microscopic and genetic analyses suggested the presence of potentially toxic Anabaena circinalis, Microcystis flos-aquae, and Cylindrospermopsis raciborskii at many locations. Low concentrations of saxitoxins and cylindrospermopsin were detected in Anabaena and Cylindrospermopsis populations. A multiplex quantitative PCR was used, employing novel oligonucleotide primers and fluorescent TaqMan probes, to examine bloom toxigenicity. This single reaction method identified the presence of the major cyanotoxin-producing species present in these environmental samples and also quantified the various toxin biosynthesis genes. A large number of cells present throughout the bloom were not potential toxin producers or were present in numbers below the limit of detection of the assay and therefore not an immediate health risk. Potential toxin-producing cells, possessing the cylindrospermopsin biosynthesis gene (cyrA), predominated early in the bloom, while those possessing the saxitoxin biosynthesis gene (sxtA) were more common toward its decline. In this study, the concentrations of cyanotoxins measured via enzymelinked immunosorbent assay (ELISA) correlated positively with the respective toxin gene copy numbers, indicating that the molecular method may be used as a proxy for bloom risk assessment.

    Original languageEnglish
    Pages (from-to)263-272
    Number of pages10
    JournalApplied and Environmental Microbiology
    Volume78
    Issue number1
    DOIs
    Publication statusPublished - Jan 2012

    Fingerprint Dive into the research topics of 'Community composition, toxigenicity, and environmental conditions during a Cyanobacterial Bloom occurring along 1,100 kilometers of the Murray River'. Together they form a unique fingerprint.

  • Cite this