New Mexico Geological Society Annual Spring Meeting — Abstracts

Carlsbad Cavern is a large limestone show cave in the Guadalupe Mountains, southeast New Mexico, that serves as both a world renown tourist attraction as well as an important location for cave science, education, and conservation. Given this extensive human footprint, Carlsbad Cavern provides a unique opportunity to investigate the impacts of human contamination in caves. Since the establishment of Carlsbad Caverns National Park in 1930, there has been extensive construction of walkways, facilities, and infrastructure in the cave to support millions of visitors. Many impacts of human contamination are well known, and the NPS has undertaken extensive conservation efforts to remove, mitigate, and remediate contamination, including regular lint removal and installing alternative lighting methods to mitigate harmful photosynthetic growth. However, less is known about the extent and mechanisms of airborne dispersal of diverse human-derived contaminants, including microbial cells, organic molecules, and other particles via the cave atmosphere and from the human aerodynamic wake. We therefore used a multidisciplinary combination of environmental microbiology, organic chemistry, and modeling to evaluate characterize close to and far from walking paths. Over the course of one year, we deployed a suite of microbial and particle collectors including aerosol samplers, microcosms, and passive microbial samplers to collect volatile and non-volatile organics, microbial cells, particulates, and other materials on various surfaces, and compare them to the background conditions in the cave. Preliminary results confirm the presence of different contamination classes across all four sites, and initial analysis of microbial DNA reveals that airborne microorganisms collected in the cave differ among locations and by passive sampler type. We will discuss the implementation and preliminary results from all contamination types, insights into the airborne microbial ecology of the cave, and lessons learned and possible recommendations for contamination monitoring efforts.