Taxonomic assessment of a toxic cyanobacteria shift in hypereutrophic Grand Lake St. Marys (Ohio, USA)
Anatoxin, Cyanobacterial blooms, Grand Lake St. Marys, Microcystin, Microcystis sp., Planktothrix sp.
Grand Lake St. Marys (Ohio, USA) is a hypereutrophic reservoir prone to persistent toxic cyanobacterial blooms fueled by agricultural nutrient runoff. The pervasive and highly toxic 2010 bloom led to the collapse of the local tourism industry, with microcystin concentrations exceeding 2000μgmL-1 at some locations during the peak of the bloom. Sampling from a location adjacent to the intake to the Celina Water Treatment Plant, chlorophyll a levels remained above 25μgL-1 from June to September, reaching a maximum in excess of 100μgL-1 in July. Molar ratios of dissolved inorganic nitrogen (DIN) to dissolved inorganic phosphorus (DIP) declined below 16 in July and August, suggesting the cyanobacterial population became N-limited during the bloom peak. Cyanobacterial biomass was dominated by Planktothrix spp. throughout late summer 2010, but phylogenetic analysis of mcyA sequences revealed the presence of toxic Microcystis spp. during July that coincided with the highest toxin measurements. August and September samples indicated the community shifted to yield Planktothrix spp. as the major toxic genus. Community shifts of this nature may impede targeted remediation efforts, and therefore a thorough understanding of the taxa involved is necessary prior to implementing strategies to limit bloom formation. © 2013 Elsevier B.V.
Steffen, Morgan M.; Zhu, Zhi; McKay, Robert Michael L.; Wilhelm, Steven W.; and Bullerjahn, George S.. (2014). Taxonomic assessment of a toxic cyanobacteria shift in hypereutrophic Grand Lake St. Marys (Ohio, USA). Harmful Algae, 33, 12-18.