TEMPERATURE REGULATES MICROCYSTIN RELEASE FROM TOXIN-PRODUCING CYANOBACTERIA
To evaluate temperature regulation of microcystin release by toxin-producing cyanobacteria, we performed year-round sampling of a eutrophic lake dominated by Planktothrix agardhii. Seasonal variation in temperature was replicated in a laboratory incubation experiment designed to evaluate cause-effect relationships between temperature and toxin release. Lake temperature ranged from 3-27°C and cyanobacteria biomass increased with warming up to 18°C, but declined rapidly with further increases in temperature. Extracellular microcystin concentration was coupled with changes in water temperature and was most elevated between 20-25°C, concurrent with the decline in cyanobacteria biomass. A similar trend was observed in laboratory incubations where productivity-specific microcystin release was greater (up to 4-fold) between 20-25°C compared to release rates between 3-19°C. However, productivity-specific microcystin release declined rapidly at 30°C. The results of this study may aid in the ability to forecast elevated toxin levels in eutrophic lakes where blooms can persist year-round with varying degrees of toxin production, thereby minimizing toxin-associated health risks.
Jeremy Walls (Primary Presenter/Author), Ball State University, email@example.com;
Kevin Wyatt ( Co-Presenter/Co-Author), Ball State University, firstname.lastname@example.org;
Jason Doll ( Co-Presenter/Co-Author), Ball State University, email@example.com;
Eric Rubenstein ( Co-Presenter/Co-Author), Ball State University, firstname.lastname@example.org;
Allison Rober ( Co-Presenter/Co-Author), Ball State University, email@example.com;