Fresh from the Ocean

Abstract

Geology Freshwater springs have been found along the Atlantic coastal shelves of North America and Europe even at depths of several hundred meters below sea level, and several hundred kilometers offshore. In some areas (for example, the southern United States), springs are emanating from coherent aquifers that are recharged high enough above sea level to provide the gravitational potential to push the fresh water out into the denser saltwater. Elsewhere though, the fresh water seems to have been trapped during glacial cycles when sea level was considerably lower. Cohen et al. provide an overview of these settings and explore their formation and resource potential through a series of numerical models. Their models suggest that extensive recharging occurred beneath Pleistocene ice sheets, which extended out onto the shelves or along submarine canyons. They estimate that some submarine aquifers off New England may contain as much as 10,000 km3 of fresh water. Globally, there may be as much as 300,000 km3 of fresh water, though it is nonrenewable. Groundwater 10.1111/j.1745-6584.2009.00627.x (2009).