We think of nothing being deeper than the bottom of the ocean. Scientists have discovered, however, that much lies beneath it. Most recently, they’ve found that there are major reserves of fresh water beneath the ocean, many kilometers out to sea. It’s so much low-salinity water – half a million cubic kilometers — that there’s already talk about using the water to prevent a “global water crisis” among many coastal cities in Australia, China, North America and South Africa.
As much as the water is needed, could demand for it set off a rush of offshore drilling with potentially drastic repercussions for the fragile marine ecosystems at the ocean’s bottom?
There’s no question that there’s an urgent need for water around the world. Today, almost half of the global population doesn’t have access to enough water, according to U.N. Water. By 2030, it’s predicted that 47 percent of the population will be living in areas of high water stress.
According to a new study in the December 5 Nature by Australian scientists, the huge freshwater reserves are located underneath the seabed on continental shelves around the world. ”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,” comments the study’s lead author, Vincent Post of the National Center for Groundwater Research and Training (NCGRT) and the School of the Environment at Flinders University in Australia. Scientists had known there was freshwater beneath the seafloor but not that there was so much and that it was so common.
It was hundreds of thousands of years ago that the reserves were formed, when the average sea level was far lower than it is now and coastlines extended further out. As Post explains,
“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.
“It happened all around the world, and when the sea level rose when ice caps started melting some 20,000 years ago, these areas were covered by the ocean.”
Layers of clay and sediment protect the subterranean aquifers from seawater.
The question remains what to do with this newfound resource. Offshore drilling is not only costly; extracting the water carries the risk of contaminating the reserves and damaging the quality of the water. The water reserves are not renewable so whatever is done must be undertaken with exceeding care. Only if the sea level drops could they be replenished; as Post notes, that “is not likely to happen for a long time.” On the other hand, it’s possible that using these underwater aquifers could be a sustainable alternative to building large new dams on land.
As Ward Sanford, a United States Geological Survey hydrologist, explains to Al Jazeera, water from the reserves would still have to undergo some kind of processing to make it drinkable. Desalination is a possibility but could be “too costly, could kill marine life, pollute water” and be “too energy intensive.”
As U.N. Water points out, many of us are using water and other natural resources at an unsustainable rate. If everyone in the world consumed water at the same rates as the average person in North America or Europe, about 3.5 Earths would be needed. Reducing how much water we consume and using what we do responsibly are crucial.
The discovery of rare metals such as gold and manganese beneath the ocean floor has already set off a rush to gain rights to mine certain regions. The adverse effects of noise pollution from deep sea drilling on whales, dolphins and other cetaceans has been documented. Efforts to draw on underwater aquifers may well only add to this. While we certainly need to provide for the world’s needs for water — especially in view of the impact of droughts and water shortages — we should do so remembering that this essential resource is needed by many other creatures too.
Photo from Thinkstock
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