In 1911, Australian explorer and geologist Griffith Taylor discovered a strange glacial feature in Antarctica, which is now known as Blood Falls. It’s a bright red waterfall, nearly five stories high, seeping through a crack in what’s now called Taylor Glacier, which flows into Antarctica’s Lake Bonney.
Geologists first believed that the color of the water came from algae, but today the red color is known to be caused by microbes living off sulfur and iron in oxygen-free water trapped beneath the ice for nearly 2 million years. The hidden lake beneath Taylor Glacier sits beneath a quarter mile (400 meters) of ice and trickles out at the glacier’s end. It deposits an orange stain across the ice as its iron rich waters rust on contact with air.
The subglacial lake beneath Taylor Glacier is thought to have been part of an ancient marine fjord system that became trapped as Taylor Glacier enclosed it between 1.5 million and 2 million years ago.
Chemical and microbial analyses both indicate that a rare subglacial ecosystem of autotrophic bacteria developed that metabolizes sulfate and ferric ions.According to geomicrobiologist Jill Mikucki at the University of Tennessee, water samples from Blood Falls contained at least 17 different types of microbes, and almost no oxygen. An explanation may be that the microbes use sulfate as a catalyst to respire with ferric ions and metabolize the trace levels of organic matter trapped with them. Such a metabolic process had never before been observed in nature.