CULTURE-BASED ANALYSIS OF CAVE WALL MICROBIAL COMMUNITIES FROM CAPULIN VOLCANO NATIONAL MONUMENT

Capulin Volcano National Monument is centered around a well-preserved cinder cone that formed during the most recent phase of volcanic activity in the Raton-Clayton Volcanic Field in Northeastern NM. The Monument contains potential relict collapsed lava tubes and other small volcanic caves in trachybasalt rock. Biological inventory of these volcanic cave microbial communities, as well as additional information on the nature and occurrence of caves in the Monument, will provide the National Park Service with records necessary for conservation as well as generate new knowledge of potential Mars analog sites. We are therefore evaluating the diversity and nature of microbial communities in high traffic and seldom visited caves, as well as evaluating whether microorganisms can access chemical energy from the cave walls. We collected wall and sediment samples from select caves and are characterizing them using culture independent and dependent analyses. We have obtained several isolates on low nutrient organoheterotrophic media, including relatives of Psychrobacillus spp., Massilia spp., and Arthrobacter spp. We are also preparing long-term enrichments on olivine and basalt from the Monument and observing any changes in microbial and chemical composition of the media over time in order to compare results with other similarly cultured basalt-metabolizing populations such as those described by Popa et al. (2012, Astrobiology v. 12 https://doi.org/10.1089/ast.2011.0639). We will describe the ongoing culture-based experiments, including plans to enrich possible nitrogen oxidizing and reducing microorganisms, as well as efforts to distinguish “weed” species and evaluate culture biases in order to better tailor conditions to relevant low nutrient and possible novel species. Due to the presence of basalt and iron-containing minerals such as olivine on Mars, which has been shown to be metabolized by microbes at basaltic rock-ice interfaces (Popa et al. 2012), studying volcanic cave surfaces on Earth may provide insight into the potential for chemolithotrophic microbial life on Mars and other extraterrestrial volcanic environments.