Scientists Discover Untapped Freshwater Reserves Beneath the Oceans
Australian scientists have identified vast freshwater reserves buried beneath the oceans offering new prospects for wiping out the alarming global water crisis.
According to the latest report documented in the journal Nature, researchers have revealed the presence of nearly half a million cubic kilometres of low salinity water located beneath the seabed on the continental shelves. Located off Australia, China, North America and South Africa, the newly discovered fresh water reserves can be used to supply water to coastal cities.
"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," says lead author Dr Vincent Post (pictured) of the National Centre for Groundwater Research and Training (NCGRT) 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 Dr. Post, the groundwater scientists were very well aware of the presence of the freshwater reserves beneath the seafloor, but have assumed it to occur during unusual and extraordinary situations. But this latest study reveals that the fresh and brackish aquifers under the seabed are a common phenomena that were formed hundreds to thousands of years ago when the sea level was lower than what it is currently.
The researchers explain that rainwater penetrated into the ground and filled up the water tables in regions that are currently under sea. This event was similar around the globe. Nearly 20,000 years ago, the sea levels rose, the ice caps began melting and the areas were covered by oceans. Most of the aquifers today are protected from seawater by blankets of clay and sediments that are piled on top. These aquifers are not different from those found below land. Their salinity is low due to which they can be easily converted into drinking water.
The study researchers propose two ways to gain access to these freshwater reserves. It could either be by constructing a platform and drilling into the seabed, which is expensive. Or drill from the mainland that is at a closer distance from the aquifer.
"Freshwater under the seabed is much less salty than seawater," Dr Post says. "This means it can be converted to drinking water with less energy than seawater desalination, and it would also leave us with a lot less hyper-saline water. 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."
An important factor that the nations with new reserves of freshwater offshore should remember is that the water reserves are non-renewable and should be used carefully. Once gone it cannot be replenished -- that is, until the level of sea water eventually drops again in the next major ice-age.