Scientists Discover 40 Craters at Lake Michigan's Bottom

In 2022, researchers began mapping the lakebed of Lake Michigan, particularly within the Wisconsin Shipwreck Coast National Marine Sanctuary, where they discovered unusual circular formations. These formations were initially thought to be depressions, but further investigation revealed they are craters, measuring between 20 and 40 feet deep. A recent survey confirmed the presence of approximately 40 craters, with the potential for more undiscovered. The craters are located in deeper waters, around 500 feet, and their formation remains a mystery. The geological context of Lake Michigan, which partially sits on limestone, suggests that these craters may be sinkholes resulting from the dissolution of the limestone. However, some researchers prefer to classify them as craters, possibly formed by water upwelling or hydrocarbon offgassing. The recent survey did not find evidence of groundwater circulation beneath the lakebed, but researchers anticipate that future studies may uncover such activity. The ecological implications of these craters are still being explored. Observations have noted the presence of freshwater shrimp, small fish, and invasive quagga mussels inhabiting the craters. Researchers are committed to studying these formations over the coming years to understand their origins and their role within the Lake Michigan ecosystem. This discovery is significant as it adds to the understanding of the Great Lakes' geological and ecological dynamics, highlighting the need for ongoing research in this area. The excitement surrounding these findings reflects the broader interest in uncovering the mysteries of the Great Lakes.