Blood Falls, an aptly named saltwater overflow from a subglacial lake in Antarctica, has been marveled at for almost a hundred years. The lake became trapped under Taylor Glacier between 1.5 and 2 million years ago. Occasional overflows allow scientists to study the trapped waters without digging through the glacier. Originally, explorers assumed that the red color came from algae. Subsequent research showed that it was the high amounts of iron in the water that was responsible for the color.
Recently, Jill Mikucki of Dartmouth College discovered that the water samples were teeming with 17 kinds of microorganisms. These organisms had survived 400 meters under a glacier with no light, heat or oxygen. How?Mikucki and her team found that the Antarctic microbes were genetically related to microorganisms known to use sulfate rather than oxygen for respiration. They hypothesized that the newly found microbes use sulfate and iron, both present in the water, to metabolize organic matter trapped in the subglacial lake. Although never before observed, such a mechanism is theoretically possible. If confirmed, this could allow life to thrive on such icy, inhospitable places as Jupiter’s moon Europa.