According to a news release from Flinders University, researchers have found massive reserves of fresh water beneath oceans, offering new chances to prevent an emerging global water crisis. They discovered that approximately 500,000 cubic km of low-salinity water are hidden beneath the seabed on continental shelves around the globe.
The water has been found off Australia, China, North America and South Africa.
“The volume of this water resource is a hundred times greater than the amount we’ve extracted from the Earth’s sub-surface in the past century since 1900,” noted lead author Vincent Post of the National Centre for Groundwater Research and Training and the School of the Environment at Flinders University. “Knowing about these reserves is great news because this volume of water could sustain some regions for decades.”
According to Post, groundwater scientists previously believed that fresh water under the seafloor only took place under special conditions, but the new research reveals that freshwater aquifers beneath the oceans are actually commonplace.
The freshwater reserves were developed over the past hundreds of thousands of years when on average the sea level was a lot lower than it is today.
“So when it rained, the water would infiltrate into the ground and fill up the water table in areas that are nowadays under the sea,” Post said.
When the sea levels rose approximately 20,000 years ago, the freshwater aquifers were shielded from salty seawater by layers of clay and sediment that are positioned on top of them.
According to Post, these aquifers can be accessed by constructing a platform out at sea and drilling into the seabed. They can also be accessed by drilling from the mainland close to the aquifers.
However, offshore drilling is expensive and should be considered in terms of cost, sustainability and environmental impact.
“Fresh water on our planet is increasingly under stress and strain so the discovery of significant new stores off the coast is very exciting. It means that more options can be considered to help reduce the impact of droughts and continental water shortages,” Post posited.
According to Post, nations with access to freshwater reserves should be careful not to contaminate them with seawater. Boreholes, for example, can endanger the quality of the water.
In addition, the reserves aren’t an infinite source of fresh water and should be accessed and used accordingly.
The study’s findings are described in greater detail in the journal Nature.