Residents and visitors around Muskegon Lake have been urged to exercise caution following reports of a harmful algal bloom, which experts say has now extended into Lake Michigan. The warning comes after Muskegon County Public Health advised the City of Muskegon on Tuesday to post advisories, as per the City of Muskegon. The signs, which are a precaution, don't confirm the presence of a harmful algal bloom in all locations around the lake, but they do urge those entering the water to be wary.

It's been several weeks since Muskegon Lake started turning a worrisome shade of green due to algae. This issue caught the attention of Muskegon videographer David J. Ruck, who took aerial photos depicting the blue-green algae making its way through the harbor channel from Muskegon Lake into Lake Michigan. According to MLive, the bloom's migration has raised concerns, particularly in light of Muskegon's Great Lakes Surf Festival taking place this weekend near the affected areas.

Harmful algal blooms (HABs) like the one in question are caused by cyanobacteria, known as blue-green algae, which can produce dangerous toxins. Jeff Johnston, a spokesperson for the Michigan Department of Environment, Great Lakes and Energy (EGLE), described the situation as a "consistent and recurring problem", as per WZZM 13. These toxins pose risks to humans and animals upon contact, ingestion, and even inhalation.

Environmental scientists like Alan Steinman of Grand Valley State University (GVSU) Annis Water Resources Institute are surprised by the bloom's persistence, stating to MLive, "It's a really unusual bloom. I wish I could tell you why it’s persisted so long, but I really can’t explain it. I’m kind of surprised, quite honestly." Despite this, there remains a cautious optimism that upcoming wind and waves might disperse it in Lake Michigan, which generally lacks the nutrients to sustain such blooms.

Officials continue to monitor the situation, and while current testing by GVSU indicates that toxin levels "weren't outrageous, but they weren't trivial either," as Steinman mentioned, per MLive, the potential risks cannot be overlooked.