Figure 1. Left Panel: Diver photo of purple mats at the shallow, sunlit Middle Island Sinkhole. Right Panel. Right Panel: Diver collected sediment core from the shallow, sunlight Middle Island Sinkhole showing the overlying purple cyanobacterial mat community. Directly underneath lay thick, organic-rich sediments. Image courtesy of Thunder Bay Sinkholes 2008.
Related Links
Thunder Bay Sinkholes 2008: Sinkholes
