Scientists Discover Giant Groundwater System Below Antarctic Ice

An anonymous reader quotes a report from Phys.Org: Now, a team has for the first time mapped a huge, actively circulating groundwater system in deep sediments in West Antarctica. They say such systems, probably common in Antarctica, may have as-yet unknown implications for how the frozen continent reacts to, or possibly even contributes to, climate change. The research appears today in the journal Science. [...] The researchers in the new study concentrated on the 60-mile-wide Whillans Ice Stream, one of a half-dozen fast-moving streams feeding the Ross Ice Shelf, the world's largest, at about the size of Canada's Yukon Territory. Prior research has revealed a subglacial lake within the ice, and a sedimentary basin stretching beneath it. Shallow drilling into the first foot or so of sediments has brought up liquid water and a thriving community of microbes. But what lies further down has been a mystery.

The team used a technique called magnetotelluric imaging, which measures the penetration into the earth of natural electromagnetic energy generated high in the planet's atmosphere. Ice, sediments, fresh water, salty water and bedrock all conduct electromagnetic energy to different degrees; by measuring the differences, researchers can create MRI-like maps of the different elements. The team planted their instruments in snow pits for a day or so at a time, then dug them out and relocated them, eventually taking readings at some four dozen locations. They also reanalyzed natural seismic waves emanating from the earth that had been collected by another team, to help distinguish bedrock, sediment and ice. Their analysis showed that, depending on location, the sediments extend below the base of the ice from a half kilometer to nearly two kilometers before hitting bedrock. And they confirmed that the sediments are loaded with liquid water all the way down. The researchers estimate that if all of it were extracted, it would form a water column from 220 to 820 meters high -- at least 10 times more than in the shallow hydrologic systems within and at the base of the ice -- maybe much more even than that.

Salty water conducts energy better than fresh water, so they were also able to show that the groundwater becomes more saline with depth. Key said this makes sense, because the sediments are believed to have been formed in a marine environment long ago. Ocean waters probably last reached what is now the area covered by the Whillans during a warm period some 5,000 to 7,000 years ago, saturating the sediments with salt water. When the ice readvanced, fresh melt water produced by pressure from above and friction at the ice base was evidently forced into the upper sediments. It probably continues to filter down and mix in today. The researchers say this slow draining of fresh water into the sediments could prevent water from building up at the base of the ice. This could act as a brake on the ice's forward motion. Measurements by other scientists at the ice stream's grounding line -- the point where the landbound ice stream meets the floating ice shelf -- show that the water there is somewhat less salty than normal seawater. This suggests that fresh water is flowing through the sediments to the ocean, making room for more melt water to enter, and keeping the system stable. The direction of water flow could be reversed if the ice surface were to thin, warn the researchers. "Overlying pressures would decrease, and deeper groundwater could begin welling up toward the ice base," reports Phys.Org. "This could further lubricate the base of the ice and increase its forward motion. Furthermore, if deep groundwater flows upward, it could carry up geothermal heat naturally generated in the bedrock; this could further thaw the base of the ice and propel it forward."

If the groundwater begins moving upward, it would bring up the dissolved carbon used by the microbes living in the shallow sediments. "Lateral groundwater flow would then send some of this carbon to the ocean," reports Phys.Org. "This would possibly turn Antarctica into a so-far unconsidered source of carbon in a world already swimming in it."

Re: PopeRatzo - [e-mail]; ask about AGW

[saloomy]

These groundwater systems are natural and would have occurred without the industrial revolution, albeit at longer time scales. For most of earths history, it was ice free. We happen to be exiting a glacial period for the last 15,000 years. Thats all.

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[JanSand]

This item is of particular interest, not just because it indicates a new understanding of the geological architecture of Antarctica, but because it indicates uncertainty as to how fast the ice will melt and raise the world's ocean level. A very large percentage of major cities are coastal and a rapid rise in ocean levels can make these cities uninhabitable and destroys much of their commercial viability.

Re: PopeRatzo - [e-mail]; ask about AGW

[saloomy]

Yes. That is what happens when we accidentally built cities in low lying coastal areas on a planet where the sea is typically higher than it is today and has been for a all but few million years of earths timeline. You do not mention however that Antarctica was a forest continent which we will gain access to if the ice cap melts off of it. The commercial value will rise

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[JanSand]

Whatever forests may rise, humanity is in its final stages of convincing Russia that the only way to halt the disease named NATO which is trying to totally destroy Russia may convince Putin that if Russia is destroyed, it is fully equipped with enough nuclear weapons to take the rest of the world with it, So the total wonder of turning dinosaurs into edible fast food as chickens has proved a failure.

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[gtall]

Yes, the ground water systems are natural. However, the rate of rise of temperatures across the Earth far exceeds what would be produced by exiting the glacial period. And given the extra warmth, the article shows feed forward flow that will dump more carbon into the atmosphere. That's all.

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[AutodidactLabrat]

Nope. Without global warming, excess ice overpack would not be creating excess pressure in downslope water-rock

What Lies Beneath Antarctica

[koko]

Is it:

1. Atlantis
2. Atlanta
3. Uranus
4. All of the above
5. None of the above

Something a kid might have to guess doing their Georgia Test of Basic Skills. What the hell happened to Georgia? Florida?

"West Antarctica"?

[Media Archivist]

Using the term "west" to describe an Antarctic location seems so... wrong?

Re:"West Antarctica"?

[thrich81]

The region is referred to as West Antarctica because it is in the longitudes of the Western Hemisphere, so actually this keeps it consistent with the rest of the world's reference frame. The regions of Antarctica relatively far from the S. Pole have quite distinct characteristics so broad names to distinguish them are useful and appropriate. Other names like "Princess Elizabeth Land" and "Marie Byrd Land" are also in use, but refer to smaller areas and are not as immediately recognizable as "West" and "East".

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[Media Archivist]

Yes, I know. It still seems kind of wrong, from a "definition of west" point of view. Compare to West Virginia or Western Australia, which are both west of something with a similar name.

I realize I'm dumber than a box of rocks

[Baconsmoke]

But I'm wondering it it would be possible to capture some of the fresh water before it goes down through the ice and be used elsewhere in the world where freshwater is almost gone. I'm thinking of desperation measures as it becomes harder and harder to come by. I live in the Western US and so the loss of fresh water is on my mind a lot and I know it is FAR worse in other parts of the world.

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[account_deleted]

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[Errol backfiring]

Quite so. Due to the use of artificial fertilizers, the present agricultural soil hardly contains any organic matter and as a result, can hardly hold any moisture.

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[JeffOwl]

Agriculture supports the population. Everything else being equal, more population = more agriculture. They can try to change and be smarter about it. Stop growing almonds in the desert, stop subsidizing ridiculous quantities of corn and soy so that it ends up in everything. But do you think that is likely?

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[account_deleted]

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[muh_freeze_peach]

Blaming Nestle is warranted, as they directly consume huge amounts of agricultural product, and thus spur the demand for agricultural water.

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[account_deleted]

Comment removed based on user account deletion

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[Alwin Henseler]

Icebergs and entire ice sheets of many km^2 break off all by themselves & float away in the ocean. Nothing stops anyone from grabbing such a chunk of ice, and drag it somewhere to use the meltwater. This idea has floated around for ages, and technically it's probably doable. Basically an engineering + economics problem.

Worth doing? 'Profitable'? Less likely. Remember there's no shortage of water in most (populated) areas around the world. Just fresh (and unpolluted!) water, in the right amounts, at u

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[muh_freeze_peach]

Seawater requires much more than desalination to be potable. Yuck!

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[bill_mcgonigle]

> But I'm wondering it it would be possible to capture some of the fresh water before it goes down through the ice and be used elsewhere in the world where freshwater is almost gone.

The average netizen doesn't like to hear this, but much of the world's "missing" water is locked up in Antarctica because we're still in an ice age. At other times Antarctica has been covered in lush forests, and it will be again when the planet warms up. The water will become part of the hydrological cycle and the whole pl

Ok, a couple beers in and all...

[aaarrrgggh]

Wow, this is cool research. It really tilts more to the unknown than the known, which is one of the many reasons I enjoy /.

Sure beats a discussion about politics these days...

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[Kochnekov]

Agreed. It is refreshing. But don't underestimate the ability of "terminally online" people to stumble into a scientific discussion and make it about politics, sadly.