Geographical location and underwater photographs of the benthic microbial mats of Lake Obersee, East Antarctica. (A) Satellite image map of Lake Obersee (71.17° S 13.39° E) in the NE corner of Untersee Oasis, Antarctica. (Satellite imagery copyright DigitalGlobe, Inc. Provided by NGA Commercial Imagery Program); (B) Oblique view of the microbial mats in Lake Obersee, depth 30 m; (C) Microbial mats in Lake Obersee, depth 15 m.