Beneath the sea floor

What if there is fresh water hidden beneath the ocean floor?In September 2025, scientists confirmed for the first time the existence of vast reserves of fresh water beneath the seafloor off the coast of New England, in the United States. The water, collected during Expedition 501 of the International Ocean Discovery Program, turned out to be far fresher than anyone expected — reaching levels close to safe drinking water limits.The discovery took more than twenty years from the first proposal to reality.In this episode, we enter the laboratories of MARUM, Center for MArine ENvironmental Sciences at the University of Bremen, where forty scientists from thirteen countries are working against the clock to analyze 718 sediment cores collected during the expedition. We speak with Doctor Brandon Dugan, from the Colorado School of Mines, and Doctor Rebecca Robinson, from the University of Rhode Island — the two co-chiefs of Expedition 501 — about what they found, what surprised them, and what questions this discovery opens for the future.The episode also confronts a larger question: in a world where global water use has increased sixfold in the past hundred years, where water infrastructure is being targeted in conflicts, and where demand from artificial intelligence alone could reach the equivalent of Spain's annual water consumption by 2027 — could the ocean floor become part of the answer?The scientists are careful: much more research is needed before this can be considered an accessible resource. But the fact that it exists, and that it can be studied, is itself a milestone.This podcast was produced as part of the ⁠FRONTIERS Science Journalism Fellowship,⁠ funded by the European Research Council under the European Union's Horizon Europe research and innovation programmeThe residency was carried out at ⁠MARUM, the Center for Marine Environmental Sciences⁠ at the University of Bremen, Germany.Graphic design was supported by Leonardo.ai.