Now, researchers are discovering that these unusual sinkholes are home to extraordinary communities of microscopic bacteria. The organisms are not new to science, but preliminary genetic analysis is showing that they are relatives of bacteria that live in the subglacial lakes of Antarctica. Others are functionally similar to the extremophile bacteria living on the black smokers of the deep ocean.
Sinkholes can develop on the floor of the Great Lakes, just as they do on land. Interestingly the lake-bottom ones can then fill with brine, rather than fresh water, as water percolates out of the bedrock saturated with minerals. This acidic, sulfate-rich, hypoxic environment supports a variety of extremophile organisms.