Vast new freshwater reserves discovered off China, Australia, North America and South Africa
Australian researchers said yesterday they had established the existence of vast freshwater reserves trapped beneath the ocean floor which could sustain future generations as current sources dwindle.
Lead author Vincent Post, Flinders University in Adelaide, said an estimated 500,000 cubic kilometres of low-salinity water had been found buried beneath the seabed on continental shelves 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," said Post of the study, in the latest edition of Nature.
"Freshwater 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 said his team's findings were drawn from a review of seafloor water studies carried out for scientific or oil and gas exploration purposes.
"By combining all this information we've demonstrated that the freshwater below the seafloor is a common finding, and not some anomaly that only occurs under very special circumstances," he said.
The deposits were formed hundreds of thousands of years ago, when the sea level was much lower and areas now under the ocean were exposed to rainfall which was absorbed into the underlying water table.
When the polar icecaps started melting about 20,000 years ago these coastlines disappeared under water, but their aquifers remain intact, protected by layers of clay and sediment.