ILLUMINATING CAVE BENTHOS IN SUBTERRANEAN ESTUARIES- BIODIVERSITY, ECOLOGY, AND ROLE IN COASTAL ECOSYSTEM FUNCTIONING

Karst subterranean estuaries (KSEs) occur worldwide where fresh and marine-derived waters mix within coastal aquifers, creating a chemical reaction zone that alters the composition of materials transported to the sea and sustains characteristic aquatic communities. Approximately one quarter of Earth’s population depends on karst (eroded limestone) water supplies that – within coastal regions – are directly threatened by rising sea level, uncontrolled groundwater extraction, and rapid coastal development. Yet, the role of these ecosystems in coastal biogeochemical cycling and groundwater health remains unknown. While pelagic constituents of flooded caves in KSEs have been studied for decades, the living benthic (cave floor / seafloor-hosted) fauna of these caves and caverns remains understudied.

Our overarching goal is to better understand how benthic biodiversity affects ecosystem functioning across subsurface environmental gradients between freshwater aquifers and the marine environment. Flooded coastal caves will allow us to study the KSEs via classic ecology and molecular barcoding methods, geochemical analysis of water and sediment, and long-term monitoring of dissolved oxygen, conductivity, and temperature. Our results will benefit marine benthic ecology and biology, biogeochemistry, paleoecology and biodiversity assessments. This interdisciplinary project will establish a multinational, multi-institutional collaboration, enhance research and scholarship opportunities at a predominantly undergraduate Hispanic-serving institution in Texas and support young investigators from under-represented groups in the sciences. For outreach, the project-associated PhD student, who is an African American female, will co-author a semi-autobiographical children’s book about cave diving and the wonders of cave-associated organisms.