Spatial pattern of Lake Erie Microcystis!
Ann Arbor, MI — Microcystis, an unpleasant and potentially toxic cyanobacterium, has bloomed every year in western Lake Erie since the early 2000s.
Routine sampling of western Lake Erie has shown that Microcystis is most abundant in water in between Maumee Bay and the offshore waters. Further analyses were conducted to determine why the spatial pattern of Microcystis abundance is observed.
"We used total protein content to estimate the potential growth rate of Microcystis," says Justin Chaffin, a doctoral student at the University of Toledo. "We found that Microcystis grows the fastest in the waters that transition from Maumee Bay and offshore Lake Erie. This matches our abundance data showing Microcystis is most abundant in the transition-zone waters."
The concentration of nutrients that fertilize Microcystis growth, nitrogen and phosphorus, decrease from very high levels in the bay to lower levels offshore. The transition-zone waters have fairly high nutrient concentrations. Nitrogen is high during early summer and drops to very low levels by fall. So Chaffin measured the nutrient status of the Microcystis to see how it correlates with grow rates. Although no strong correlations were found, Microcystis was deficient of phosphorus and high in nitrogen. This was surprising because most of the samples were collected when nitrogen concentration was very low, suggesting phosphorus limits Microcystis abundance even when nitrogen is low.
Original Publication Information
Results of this study, "Assessment of Microcystis growth rate potential and nutrient status across a trophic gradient in western Lake Erie ," are reported by Justin D. Chaffin, Thomas B. Bridgeman, Scott A. Heckathorn and Sasmita Mishra in the latest issue (Volume 37, No. 1, pp. 92-100) of the Journal of Great Lakes Research, published by Elsevier, 2011.
Contacts
For more information about the study, contact Justin Chaffin, Dept. Environmental Sciences and Lake Erie Center, University of Toledo, Oregon, OH 43616; justin.chaffin@rockets.utoledo.edu; (419) 530-8384.
For information about the Journal of Great Lakes Research, contact Marlene Evans, Editor, National Water Research Institute, Environment Canada, 11 Innovation Boulevard, Saskatoon, SK, S7N 3H5, Canada; jglr@ec.gc.ca; (306) 975-5310.
Since 1967, IAGLR has served as the focal point for compiling and disseminating multidisciplinary knowledge on North America's Laurentian Great Lakes and other large lakes of the world and their watersheds. In part, IAGLR communicates this knowledge through publication of the Journal of Great Lakes Research, available to members in print and electronic form. A searchable archive of the journal is available online and includes the abstracts of articles from the journal's inception in 1975 through the most recent issue. In addition, complete articles are available to members who have signed up for an electronic subscription.