Cave-wall Biofilms

The cave wall offers a distinct habitat for microorganisms. The pH of liquid droplets on the wall range from 2 to 0, and some of those droplets have the appearance of mucus, similar to the "snottites" found in Cueva de Villa Luz and the Frasassi Caves (see other sulfidic karst systems). Enrichment cultures of the mucus reveals the presence of acidophilic, sulfur-oxidizing bacteria. Other enrichment cultures and DNA work will hopefully provide more information about this interesting habitat. 

The cave-wall biofilms are also associated with mineral formation, including elemental sulfur, gypsum, and Fe-crusts. Quartz crystals have also been found in nearly every sample examined using SEM. These quartz crystals range from 1 mm to 10 mm across, and show no pitting or secondary dissolution. Most are doubly-terminated euhedral crystals, like tiny footballs! Other researchers have also reported the occurrence of quartz precipitation at low temperatures from Carlsbad Caverns, but the mechanism for this is currently being investigated by our group. 

Scanning Electron Microscopy of Microbial Mat and Sediments:

Microbial biofilms and sediments were preserved in gluteraldehyde, then freeze-dried. Prepared samples were gold-coated and observed using the JEOL SEM in the department. The images were digitally captures and the size was adjusted to fit on the web-page, causing some distortion.