2023 Early Hearing Detection & Intervention Conference

March 5-7, 2023 • Cincinnati, OH

5/21/2018 | 9:15 AM - 9:30 AM | MICROCYSTINS AND SAXITOXINS IN THE WESTERN AND CENTRAL BASINS OF LAKE ERIE | 420 B

MICROCYSTINS AND SAXITOXINS IN THE WESTERN AND CENTRAL BASINS OF LAKE ERIE

Western basin (WB) microcystin-producing Microcystis blooms have been well-studied for the past decade. Several years of field data have indicated that the ratio of microcystin concentration-to-Microcystis biomass declines throughout summer as nitrate concentration declines. Laboratory experiments with natural WB Microcystis have shown that increased concentrations of nitrate, ammonium, and urea increase microcystins, bloom biomass, up-regulates microcystin synthetase genes. The field and experimental data indicate that nitrogen has an essential role in constraining WB bloom toxicity. In contrast to microcystins, there is less known about saxitoxins in Lake Erie. Satellites have detected cyanobacterial blooms in the offshore waters of the central basin (CB) in several recent years. Field samples from the CB have determined that the dominant cyanobacterium was Dolichospermum – a known saxitoxin producer. A saxitoxin gene (sxtA) was present in 67% of samples collected during Julys of 2016 and 2017; however, the sxtA was not detected in August when Dolichospermum was not present. Additionally, saxitoxins were present at low concentrations (< 0.03 ppb) in surface samples collected in July 2017. In conclusion, researchers are building forecasts for microcystins, whereas saxitoxins are an emerging concern.

Great Lakes
Phytoplankton
Water Quality

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Presenters/Authors

Justin Chaffin (), Ohio State University, Stone Laboratory and Ohio Sea Grant, chaffin.46@osu.edu;