Water samples from Canyon Lake from surface to deepest waters (left to right). Samples from below about 17 m depth show a dark brown color due to dissolved iron and other chemicals; they are also effervescent and smelly.
Researchers have long been attracted to Canyon Lake as a geomorphological oddity. Carved by glacial outwash floodwaters, its extreme depth relative to its width, and the protection from wind afforded by its bounding cliffs mean that winds can never provide enough energy to mix its waters all the way to the bottom. Consequently, the bottom several meters of the lake have remained isolated from the atmosphere at least for decades — perhaps centuries or millennia. Waters below the ‘mixing zone’ have become completely devoid of oxygen (anoxic) and only specialized types of anaerobic bacteria can survive there. Certain chemicals tend to build up in the deep waters resulting in a sharp chemical transition — a ‘chemocline’ — separating the shallower, mixed waters and deeper, unmixed waters.
A number of lakes with permanently unmixed and anoxic bottom waters (classified as ‘meromictic’ lakes) are known, and Canyon Lake has been recognized as meromictic since 1940. Several researchers have found it interesting for that reason, but preliminary work during the 2014 season by Prof. Chad Wittkop — a geologist and chemist at Minnesota State Univ. at Mankato — suggests that Canyon Lake may be quite unusual even in this oddball category of lakes. His preliminary report notes that the deep waters of Canyon have a rare combination of high dissolved iron concentrations and low sulfate concentrations (“ferruginous” conditions). Ferruginous lakes are quite rare, and Canyon may be the smallest known so far. These conditions provide habitats that foster the growth of very unusual types of bacteria, including types that may have been typical of early Pre-Cambrian oceans in the earliest days of life on earth.
Wittkop notes several other odd properties of the lake’s deep waters and hopes to follow up on these in future research. This work is likely to connect with previous work examining Canyon Lake sediments by paleoecologist Dr. Steve Jackson (then Univ. of Wyoming) and recent work on water chemistry by Dr. Jay Lennon and Mario Muscarella (Indiana Univ.), thus building on both the unique natural features of the Huron Mts. and on the existing and ongoing research program of the Huron Mt. Wildlife Foundation.