On Thursday, October 27th, a resident posted pictures on Facebook taken at Marcus Park of a potential algae bloom. A sample was brought to GVSU’s Annis Water Resources Institute and positively identified as the cyanobacteria (formerly blue-green algae) Dolichospermum. I’m very grateful to Dr. Rediske for of the Water Resources Institute for offering to take time out of his day and personally identify the sample himself. This is considered a harmful algal bloom (HAB), and Dr. Rediske has offered to investigate grants for monitoring Duck Lake in the future for algae blooms. The algae bloom appears to be confined to the westernmost shore of Duck Lake. All physical contact with the algae should be avoided, and absolutely do not allow your pets near any water that looks like this. Algae blooms in and of themselves are a natural part of many lakes yearly cycle, but a warming and changing climate has led to the increase in HAB’s in the Great Lakes, and Duck Lake will be no exception. Please see the link below from Michigan’s EGLE for more information on HAB’s, including how to report them when you see one. I’ve also included some information on Dolichospermum itself. Dr. Rediske noted it was very unusual to see this species of algae this time of year. Dolichospermum can survive and outcompete other algae at times of year, like the fall, when levels of two of the most important nutrients, nitrogen and phosphorous, are decreasing. Dolichospermum can take nitrogen present in the air and use it to photosynthesize, allowing it to outcompete other algae. This is good news, because it does not necessarily indicate that this algae bloom is the result of excessive nutrients, leaking septics, etc. Later this Fall or Winter, we will have an informational session at the White Lake Library or the Township Hall about HAB’s and other emerging threats to the Great Lakes.
https://www.michigan.gov/mdhhs/news/2022/08/08/hab-tracker
https://ohioseagrant.osu.edu/research/plankton/dolichospermumanabaena