121-5 Evaluating the dispersal of airborne human-derived contaminants in Carlsbad Cavern, NM

Session: Caves and Karst Through Space and Time: Biogeochemistry, Climate, and Astrobiology

Presenting Author:

Joseph Hoberg

Authors:

Hoberg, Joseph¹, Weber, Autumn², Hargarther, Michael J³, Graham, Heather V⁴, Regberg, Aaron⁵, Chung, Angela⁶, Weiss, Gabriella⁷, Jones, Daniel S⁸

(1) Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, NEW MEXICO, USA, (2) Department of Mechanical Engineering, New Mexico Institute of Mining and Technology, Socorro, NM, USA, (3) Shock & Detonation Physics, Los Alamos National Laboratory, Los Alamos, NEW MEXICO, USA, (4) Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA, (5) Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, Texas, USA, (6) Goddard Agnostic Biosignatures Collective and Center for Research and Exploration in Space Sciences and Technology, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA, (7) Goddard Agnostic Biosignatures Collective and Center for Research and Exploration in Space Sciences and Technology, NASA Goddard Space Flight Center, Greenbelt, Maryland, USA, (8) National Cave and Karst Research Institute, Carlsbad, New Mexico, USA,

Abstract:

Carlsbad Cavern is a large limestone cave that is the primary tourist attraction in Carlsbad Caverns National Park, southeast New Mexico. Since the establishment of the National Park in 1930, extensive construction of artificial walkways, facilities, and infrastructure have been undertaken to support the hundreds of thousands of annual visitors to the cave. Although the National Park Service has implemented extensive conservation efforts to mitigate the impacts of contamination to the cave, human-derived materials still occur throughout, and the extent and dispersal of airborne human-derived contaminants, including microbial cells, organic molecules, and other particles, remain poorly understood. We therefore utilized environmental microbiology, organic chemistry, and particle monitoring to evaluate contaminant dispersal close to and far from walking paths and evaluate different methods to capture and detect different classes of contaminants. Over the course of a 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. Additionally, these field-based techniques were paired with new methods to model contaminant dispersal from walking people to evaluate the human aerodynamic wake. Overall, results confirm the presence of all contaminant classes at every investigated site, even after three weeks of deployment. Analyzing extracted microbial DNA revealed that approximately 10% of the identified genera from each collector type are associated with a human microbiome database. Moreover, GC-MS and high-resolution microscopic analysis reveal that synthetic human-sourced organic molecules and particulates, including microfibers, persist throughout accessible and remote areas of the cave. These findings provide insights into the natural and human-influenced airborne microbial ecology of the cave, and we aim to apply lessons learned towards contamination monitoring efforts and approaches for evaluating contaminant detection in pristine environments.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7350

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