How the one-two punch of a herbicide shapes Cyanobacterial Communities
Ann Arbor, MI — Toxic cyanobacteria have re-emerged in the Laurentian Great Lakes – especially Lake Erie – over the past 15 years and become a nuisance to tourism, industry and lake management. While many researchers have focused on nutrient loading as a factor that controls how much algal biomass appears in the lake, few have focused closely on why we get different populations of cyanobacteria in different locations of the lake system.
Researchers at the University of Tennessee and Environment Canada teamed up to understand how other materials flowing into Lake Erie from the water shed might work to shape the algal community. Their work suggests that the herbicidal compound glyphosate, which others have shown enters and persists in Lake Erie, might work to inhibit some algae while promoting others. "We have wondered for some time why we get Microcystis blooms in the western basin and Planktothrix blooms in places like Sandusky Bay" says Steven Wilhelm, a Professor of Microbiology at the University of Tennessee. "The work of Matt [Saxton] and others has shown that glyphosate inhibits growth of Microcystis, while it acts (with a little help from the rest of the microbial community) as a phosphorus source to Planktothrix, which in turn can make toxins similar to those Microcystis makes. These observations provide insight into a factor that may shape the microbial community and lead to different populations in locations with otherwise similar water chemistry".
Original Publication Information
Results of this study, "Glyphosate influence on phytoplankton community structure in Lake Erie," are reported by Matthew Saxton, Elizabeth Morrow, Richard Bourbonniere and Steven Wilhelm in Volume 37, No. 4, of the Journal of Great Lakes Research, published by Elsevier, 2011.
Contacts
For more information about the study, contact Professor Steven Wilhelm, Department of Microbiology, The University of Tennessee, Knoxville, TN 37996; wilhelm@utk.edu, (865) 974-0665.
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.