ELUCIDATING BIOFILMS IN PUERTO RICO’S KARSTIC CAVES – A COLLABORATIVE COMMUNITY-GEOSCIENCE APPROACH TO EDUCATION AND PRESERVATION OF RUPESTRIAN ROCK ART

Caves are important for their cultural significance and often contain rich pieces of archaeological history, including rupestrian rock art (pictographs and petroglyphs). They are also a fragile and ecologically distinct home to specialized forms of life, with biofilms being of particular importance due to their involvement in numerous forms of geochemical cycling. Biofilms are comprised of multiple taxa that are sensitive to environmental changes and their community composition varies based on the dominant form of nutrient input. Studies conducted in some show-caves indicate that shifts in microbial community composition may occur in response to anthropogenic activity. Often, native community members are outcompeted and replaced by taxa that are capable of endolithic metabolism. Since endolithic taxa acquire their nutrients from the host rock by modifying it or directly degrading it, they are undesirable for the preservation of caves. However, their impact on the preservation of rupestrian rock art remains poorly understood.

This study is part of a partnership between scientists from multiple disciplines, community leaders from Cabachuelas, and local community members in Puerto Rico. The goal is to determine if variances in ecotourism impact biofilm composition and subsequently discuss implications for cave and rupestrian rock art preservation. Objectives include characterization of the host rock and biofilms of contrasting (heavily vs. seldom trafficked) karstic caves on the main island. This will be done by conducting 1) SEM-EDS and electron microprobe geochemical analyses of the host rock, and 2) genomic and cultural analyses of the biofilm community members. If endolithic taxa are identified, Cabachuelas and the local community will be able to utilize the findings to modify existing sustainable ecotourism practices to preserve the caves and any rupestrian rock art. The co-generation and delivery of educational materials – including maps of the caves and informational leaflets – aims to raise awareness of career opportunities in archaeology, microbiology, and geology. Emphasizing community engagement will highlight the importance of community collaboration in co-creating knowledge and providing long-term, sustainable solutions for ecotourism and public geoscience education.