The shipwrecks of Thunder Bay National Marine Sanctuary offer a glimpse into our nation's maritime history, but did you know that Lake Huron also gives scientists the opportunity to understand life as it was billions of years ago?
Submerged sinkholes in Lake Huron vent cool, oxygen-free groundwater into the lake bottom. Since this water is denser than normal lake water, it forms a distinct layer on the lake floor that is the perfect habitat for low-oxygen-tolerant bacteria -- microorganisms that are similar to those that lived in Earth's shallow seas 2.5 billion years ago. The Thunder Bay National Marine Sanctuary research team regularly conducts scientific dives for researchers from Grand Valley State University’s Microbial Biology Lab, the University of Michigan’s Geomicrobiology Lab, the University of Wisconsin-Stout, and NOAA’s Great Lakes Environmental Lab as they characterize the special ecosystem present at the Middle Island sinkhole.
Here, a NOAA diver takes a bacterial mat sample from the Middle Island sinkhole. Learn more about the research conducted in the sanctuary.
(Photo: Joe Hoyt/NOAA)