Blood Falls, a subglacial discharge from the Taylor Glacier, Antarctica provides an example of the diverse physical and chemical habitats available for life in the polar desert of the McMurdo Dry Valleys. Geochemical analysis shows that Blood Falls outflow resembles concentrated seawater remnant from the Pliocene intrusion of marine waters combined with products of weathering. The result is an iron-rich, salty seep at the terminus of Taylor Glacier, which is subject to episodic releases into permanently ice-covered Lake Bonney. Blood Falls influences the geochemistry of Lake Bonney, and provides organic carbon and viable microbes to the lake system. Presented here is the first data on the geobiology of Blood Falls, and relate it to the evolutionary history of this unique environment. The novel geological evolution of this subglacial environment makes Blood Falls an important site for the study of metabolic strategies in subglacial environments, and the impact of subglacial efflux on associated lake ecosystems.