Sheboygan, Wisconsin – Researchers from the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory have discovered a series of intriguing sinkholes at the bottom of Lake Michigan. Approximately 40 circular structures were identified during a recent expedition, sparking interest and curiosity among scientists and researchers. These unusual depressions, measuring between 91 meters and 183 meters in diameter, were first detected using sonar technology during a survey of the Great Lakes in 2022.
The sinkholes, believed to have formed through typical geological processes, were found around 22.5 kilometers southeast of Sheboygan, aligned in a line extending toward Port Washington. Shipwreck hunter Brendon Baillod, who initially noticed the structures, described them as ranging between 500 and 1,000 feet in diameter and irregular in shape. This discovery has piqued the interest of researchers due to the potential insights it may offer into early Earth conditions.
According to the US Geological Survey, sinkholes are most commonly found in karst terrain, where certain types of rock beneath the surface can naturally dissolve due to groundwater circulation. In the case of Lake Michigan, the limestone bedrock plays a significant role in the formation of these sinkholes. These structures, while seemingly ordinary, may house unique microbial communities similar to those found in sinkholes in Lake Huron.
Research on the sinkholes in Lake Huron has revealed the presence of diverse microorganisms, including bacteria, Archaea, and Eukarya. DNA analysis of the purple mat formed by bacteria on the lake floor has shown the prevalence of Phormidium autumnale, a photosynthetic cyanobacterium. These findings suggest the existence of potentially undiscovered microbial life forms, indicating the need for further exploration and research in Lake Michigan.
Scientists at GLERL believe that studying the sinkholes in Lake Michigan could provide valuable insights into early Earth conditions and the unique microbial ecosystems thriving in oxygen-poor, sulfur-rich environments. Further research is required to determine the extent of similarities between the sinkholes in Lake Michigan and Lake Huron, shedding light on the fascinating connections between geology and biology beneath the surface of the Great Lakes.