Cyanobacterial toxins in lower Green Bay, Lake Michigan

Session: 41a. - Great Lakes Harmful Algal Blooms Research from Watershed Influence to Ecosystem Effects

Sarah Bartlett, NEW Water Green Bay Metropolitan Sewerage District , [email protected]
Erin Houghton, NEW Water Green Bay Metropolitan Sewerage District, [email protected]
Donalea Dinsmore, Wisconsin Department of Natural Resources, [email protected]
Gina LaLiberte, Wisconsin Department of Natural Resources, [email protected]
Todd Miller, University Wisconsin-Milwaukee, [email protected]

Abstract

Cyanobacterial harmful algal blooms (cyanoHABs) are a growing problem in freshwater systems worldwide. Toxin-producing blooms are well documented in the Laurentian Great Lakes but little is known about the environmental drivers of cyanoHAB growth and toxicity in Green Bay, Lake Michigan. Excess nutrients from urban and rural runoff, along with sediment and phosphorous loading from the Lake Winnebago and Fox River water systems into Green Bay aid in cyanoHAB formation and proliferation, which can be toxic to humans and animals. Depth discrete samples were collected from six sites in lower Green Bay, including four sites in a transect moving through the designated Area of Concern, and two eastern shorelines sites - Bay Beach and Joliet Park. In addition to assessing the diversity of twenty different cyanobacterial toxins including eleven microcystin variants, other measured variables include pigments, nutrients, and cyanobacterial taxa counts. Microcystis aeruginosa prevailed as a dominant taxa throughout the season and of the microcystin variants targeted, microcystin-LR and microcystin-RR were co-dominant toxins. A toxin gradient was observed with the highest microcystin concentrations measured along the eastern shore and at the mouth of the Fox River. Similarly, pigment fluorescence and several nutrient analytes followed the toxin gradient.

1. Keyword
Green Bay

2. Keyword
eutrophication

3. Keyword
water quality

4. Additional Keyword
cyanobacteria

5. Additional Keyword
cyanotoxins