The following text is an artificial-intelligence-generated, expert-checked summary of a key research study cited in a feature article from Scientific American’s July/August 2023 issue: “Found: Giant Freshwater Deposits Hiding under the Sea,” by Rob L. Evans.
You can find the study itself here: “Aquifer Systems Extending Far Offshore on the U.S. Atlantic Margin,” by Chloe Gustafson et al., in Scientific Reports, Vol. 9, Article No. 8709. Published online June 18, 2019.
Offshore groundwater is important for ocean life and global carbon cycling. But figuring out where low-salinity groundwater is in continental shelves is tough. Now a new study led by Chloe Gustafson of Columbia University and her colleagues has mapped a huge offshore aquifer system along the U.S. Atlantic coast using marine electromagnetic methods.
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The researchers did the first big marine electromagnetic survey of low-salinity groundwater in two spots on the U.S. Atlantic coast: near Martha’s Vineyard and New Jersey. They found continuous aquifers stretching from onshore New Jersey and Martha’s Vineyard to 90 kilometers offshore. The aquifer system holds at least 2,800 cubic kilometers of water with salinity less than 15. This means it’s a freshwater resource that’s as big as the largest onshore aquifers.
These findings are important for understanding how continental shelves work. They could also help improve paleohydrologic modeling, which is the study of past water systems. Plus, the low-salinity groundwater could be a huge resource for future offshore groundwater production. This study helps us learn more about groundwater systems along the U.S. Atlantic coast and shows that marine electromagnetic data are useful for mapping offshore groundwater.