Torch Lake sees growth of ‘oozy, yucky, mucky’ golden brown algae
Central Lake, Mich. — A northern Michigan lake that’s famous for its turquoise waters is facing an outbreak of brown algae that’s left its sandy bottom covered with mushy, squishy mats.
Rick Welsh, a part-time lakeshore resident, said the golden brown algae was first noticed about a decade ago, but now grows in thick mats and sticks to the otherwise sugar-sand bottom of the lake in Antrim County’s Torch Lake.
“It’s oozy, yucky and mucky,” Welsh told the Traverse City Record-Eagle. “It easily comes up when disturbed.”
Welsh, a member for the Torch Lake Protection Alliance, said that there are investigations into the algae with results due in the fall.
Officials with the Michigan Department of Environment, Great Lakes and Energy, have said it appears to be a non-harmful form of algae.
Torch Lake has the second largest surface area of any inland Michigan lake, but its depth — up to 300 feet — makes it easily the state's most voluminous.
Studies of the algae blooms have been ongoing since at least 2015, according to the Three Lakes Association, a non-profit corporation focused on the water quality of the Chain of Lakes Watershed in Antrim County.
At least one study done of benthic golden algal bloom in Torch Lake for the association, which includes Lake Bellaire, Clam Lake and Torch Lake, found human marker Ace-K in groundwater samples in 2018.
Acesulfame potassium, or Ace-K, in water samples from lake water and groundwater in 2018 suggested groundwater enriched with compounds from septic drainfields was entering the lake. Ace-K, a man-made product, is a sugar substitute 200 times sweeter than sugar and is not utilized by the body, the report said, but eliminated in urine. It is found in such foods as sodas and fruit juices; dairy products including ice cream; baked goods; jams and jellies; table top sweeteners, toothpastes; gum; and salad dressings.
The Torch Lake Protection Association this year contracted with Environmental Consulting & Technology, Inc. to monitor changes to the lakes, determine the sources of nutrients feeding the algae and propose courses of action.
In the meantime, the association has launched a "Keep Torch Blue" campaign, discouraging the use of fertilizers and encouraging the maintenance and care of septic systems, two of the primary suspects in the feeding of golden brown algae.
Similar algal blooms, to varying degrees, are now found in many lakes in northwest Michigan, according to experts consulted by the Three Lakes Association.