Working under the guidance of Mike Scheiwe of Headwaters Environmental Station, Robert Heyman carefully examined microscopic algae from the lake.
Twenty five genera of algae were found. Overall, the diversity of algae found indicate that Gratiot is a healthy lake.
Among the types observed were Tabellaria and Cyclotella which are usually indicators of clean water. Robert found Cllosterum a species that sometimes clogs water filters. Gloeotrichia forms spherical algal colonies visible to the naked eye. An abundance of Gloeotrichia was observed when hot summer weather prevailed. Contact with such blooms of Gloeotrichia can cause skin irritation.