Recent research has unveiled large freshwater reservoirs located beneath the Atlantic seafloor, extending from New Jersey to Maine. This discovery, made during a two-and-a-half-month expedition involving over 40 scientists, indicates that freshwater exists at depths where seawater typically dominates. The freshwater found has salinity levels significantly lower than that of seawater, with the nearest site showing less than 1 ppt salinity. Preliminary analyses suggest that this freshwater likely originated from glacial activity approximately 20,000 years ago. However, similar freshwater sources have also been identified off the coasts of South Africa and Florida, indicating that local geological conditions may facilitate the movement of freshwater from land to seabed. Despite the potential of these reservoirs as a backup water supply, researchers caution that extracting this water could be costly and may harm sensitive marine ecosystems.