Thunder Bay National Marine Sanctuary 2007 Sinkhole Project
Ongoing research by Grand Valley State University’s Dr. Bopi Biddanda and Scott Kendall, and University of Wisconsin’s Dr. Steve Nold has discovered that the Thunder Bay sinkhole ecosystems are biogeochemical hotspots of microbial and geochemical activity. To collect water samples and deploy instruments measuring salinity and conductivity, archaeologists Tane Casserley (MHP), Russ Green (TBNMS), and Joe Hoyt (ECU) aided the researchers by becoming their eyes and hands on the lake bottom. Used to working in fragile environments and conducting delicate work, archaeologists have a specialized skill set that can be of immense value to multi-disciplinary science missions. Working in 21m of water the archaeologists worked over 4 days with a typical water temperature of 34F.
Working in this unique ecosystem the divers had to use extreme care not to disturb the diverse varieties of anaerobic bacteria that abound in this oxygen poor environment. By exhibiting buoyancy control learned after years of diving on fragile shipwrecks, they were able to accomplish complex tasks all the while hovering inches above the delicate bacteria mat below them. The assignment was made even more complex by a water density change approximately 2m above the bottom which can be seen as a haze layer or lens above the bottom. It was a new experience for the archaeologists and there are already plans for next year’s sinkhole project for the two sciences to collaborate together again.