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Investigating the ecology of microcystin synthesis in freshwater toxic harmful algal blooms via DNA/RNA metabarcoding
Citation:
Banerji, A., M. Bagley, Dan Tettenhorst, C. Nietch, Joel Allen, AND J. SantoDomingo. Investigating the ecology of microcystin synthesis in freshwater toxic harmful algal blooms via DNA/RNA metabarcoding. SETAC North America Virtual Cnference, Duluth, MN, November 15 - 19, 2020. https://doi.org/10.23645/epacomptox.13182512
Impact/Purpose:
Communication of past findings regarding Agency investigations of harmful algal blooms and facilitation of stakeholder engagement, networking, and collaboration.
Description:
The presence of the cyanobacterial hepatotoxin microcystin in drinking water and natural aquatic systems has become a global concern. Understanding the environmental factors that cause cyanobacteria to produce microcystin is crucial to the development of lake management strategies to minimize harmful exposures. While the literature is replete with studies linking microcystin production to putative grazers, competitors, nutrients, and abiotic stressors, few studies have been designed to test the relative importance of these factors or their potential synergism, and no study has been able to convincingly single out any particular factor as a consistent driver in aquatic systems. We performed random forest regression analyses using 16S and 18S rRNA gene sequencing data and environmental data obtained from a eutrophic freshwater reservoir to determine which biotic and abiotic factors best explained spatiotemporal variation in concentrations of total microcystin and several specific congeners. Model performance was best for prediction of the concentrations of the congener MC-LR, with ca. 88% of spatial and temporal variance explained. Most of the variance was associated with the relative abundance of the toxic cyanobacterium Microcystis. Additional taxa, including other cyanobacteria, heterotrophic bacteria, and bacterivorous protists, were also important components of the model, as were pH, total reactive phosphorus, and dissolved oxygen. Overall, our results are indicative of microcystin being a response to multiple environmental factors, some of which seemingly unrelated to prevailing hypotheses of microcystin’s function.
URLs/Downloads:
DOI: Investigating the ecology of microcystin synthesis in freshwater toxic harmful algal blooms via DNA/RNA metabarcoding