lunes, 9 de diciembre de 2013

Plenty of freshwater found beneath seabed


Scientists may have discovered a possible solution for the world’s mounting water problems.
An Australian research team has found huge reserves of freshwater under the seabed off North America, South Africa, Australia, and China. 

As the study’s lead author Dr. Vincent Post of Flinders University’s School of the Environment and National Centre for Groundwater Research and Training (NCGRT) puts it, “knowing about these reserves is great news because this volume of water could sustain some regions for decades.”

According to the study titled “Offshore fresh groundwater reserves as a global phenomenon,” which was recently published in Nature, the international science journal, around half million cubic kilometers of freshwater lies buried beneath the bed of the sea. Dr. Post says, “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.

According to Dr. Post, scientists were aware of the presence of freshwater beneath the sea bed, but believed that it could be found only in certain rare circumstances. He said: “Our research shows that fresh and brackish aquifers below the seabed are actually quite a common phenomenon.

Explaining the phenomenon further, Dr. Post said that the freshwater reserves were formed over a period of several hundreds and thousands of years. Back in those years when the sea level was lower than the present level, water could filtrate through the ground and occupy water tables in regions that are today submerged beneath the sea, and this happened in regions worldwide. Around 200 centuries ago, ice began melting and the sea level began to rise, covering these areas with sea water. The aquifers are protected and separated from the salty water of the sea by several layers of sediment and clay, and there is a great resemblance between the aquifers beneath land and those beneath the seabed. 

So how can we access these aquifers?
Dr. Post says that they can be accessed by either drilling directly into the seabed or drilling from land close to the freshwater reserves. He says, “Freshwater under the seabed is much less salty than seawater. 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.

He also warns that the reserves should be used with care as they non-renewable. If they are gone, we have to wait for the sea level to drop once again for them to get replenished and this is definitely not going to happen in the near future.

ORIGINAL: Digital Journal
By Sonia D'Costa
Dec 9, 2013

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