Samples of a microbial mat at the bottom of a 75-foot-deep sinkhole off the north shore of Middle Island, near Rockport State Recreation Area in the waters of Thunder Bay National Marine Sanctuary in Lake Huron, answers a question scientists have asked for decades about the rise in Earth’s oxygen levels. Read the full story by The Alpena News.
Great Lakes Commission
https://www.glc.org/dailynews/20210913-sinkhole