August 2021: Moorea and Tetiaroa in French Polynesia

Matt Becker, Ben Hagedorn, Francine Cason, Ellen Justis, Brittney Maine, and Matt Schweiger headed to Moorea and Tetiaroa in French Polynesia as part of an NSF grant to study groundwater flow to reefs. Our hypothesis is that must of the groundwater shed by the island underflows the reef. We found good support of this hypothesis when we cored through the reef to find freshened groundwater off Moorea. Electrical resistivity showed that this underflow is apparently ubiquitous about the reef. Radon and chemical tracers indicated small amounts of groundwater discharges to the reef itself, where it may impact coral biology.