Subglacial outflow from the Taylor Glacier in the McMurdo Dry Valleys, Antarctica. Iron and salt precipitates form where subglacial brine flows from the Taylor Glacier, lending a bright red color to the glacier snout, which is commonly referred to as Blood Falls. The episodic release of subglacial brine at Blood Falls provides a sample of what is believed to be ancient seawater originating from the Pliocene Epoch, which is now trapped below the glacier. The microbial diversity associated with Blood Falls reflects this marine origin. Photo by Benjamin Urmston.