You are here:
Evaluating prevailing hypotheses regarding the ecological function of microcystin using metabarcoding and environmental data
Citation:
Banerji, A., M. Bagley, J. Shoemaker, D. Tettenhorst, C. Nietch, Hubert Allen, AND J. Santo Domingo. Evaluating prevailing hypotheses regarding the ecological function of microcystin using metabarcoding and environmental data. 2019 Ecological Society of America Annual Meeting, Louisville, KY, August 11 - 16, 2019.
Impact/Purpose:
Communicate findings of a study designed to infer what drives cyanobacterial production of the toxin microcystin using ecological data obtained from Lake Harsha (Batavia, OH). The audience (participants of ESA) generally may comprise academics, consultants, and natural resource managers from around the nation.
Description:
Background/Question/Methods Microcystin is a cyanobacterial hepatotoxin of 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, the evidence has not convincingly pointed to any single factor as a consistent driver. We performed random forest regression analyses with 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. Results/Conclusions 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, not all of which are definitively related to prevailing hypotheses of microcystin’s function.
