RUI: Groundwater occurrence and discharge at coral atoll and barrier reef systems

California State University-Long Beach Foundation, Long Beach CA

Investigators

Abstract

Preservation of reef ecosystems in the face of climate change is one of the most pressing challenges in natural science. It requires thorough understanding of the interactions between terrestrial and reef environments. An important interaction is the flow of groundwater to the ocean as a key driver of environmental change in tropical island coral reefs. This study explores the hydrogeology of reef systems and traces the flow of groundwater and related chemicals to and through these systems. Results from this research benefit society by providing needed information about the role of submarine groundwater discharges on the health of reef systems. The project also serves to broaden the education and training of graduate and undergraduate students in a primarily undergraduate institution and partner with local organizations to increase scientific knowledge among community members. A short video documentary will be produced and distributed through media outlets and the National Geographic OpenExplorer blog site to reach a broad audience. The purpose of this work is to map, measure, and image the hydrogeology of reefs on a French Polynesian volcanic island (Mo’orea) and coral atoll (Tetiaroa) so that the groundwater flow to reefs can be constrained and up-scaled. The research integrates electrical resistivity profiling, radioisotope analysis, fiber optic distributed temperature sensing, coring and dye transport studies, thermal imagery, and numerical modeling, to trace groundwater movement to and through the reef. Proxies for reef metabolism, total alkalinity and dissolved inorganic carbon are analyzed to gage impact of submarine groundwater discharge on reef ecosystem functioning in an acidifying ocean. The results of this work support future strategic investigations of hydrologic impacts on both atoll and high-island reefs, including the NSF-funded Mo’orea Coral Reef Long Term Ecological Research (LTER) project. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.