In Sediments Below Antarctic Ice, Scientists Discover a Giant Groundwater System

Previously unmapped reservoirs could speed glaciers, release carbon

Peer-Reviewed Publication

COLUMBIA CLIMATE SCHOOL

On the ice
IMAGE: LEAD AUTHOR CHLOE GUSTAFSON AND MOUNTAINEER MEGHAN SEIFERT INSTALL GEOPHYSICAL INSTRUMENTS TO MEASURE GROUNDWATER BELOW WEST ANTARCTICA’S WHILLANS ICE STREAM. view more 
CREDIT: KERRY KEY/LAMONT-DOHERTY EARTH OBSERVATORY

Many scientists say that liquid water is a key to understanding the behavior of the frozen form found in glaciers. Melt water is known to lubricate their gravelly bases and hasten their march toward the sea. In recent years, researchers in Antarctica have discovered hundreds of interconnected liquid lakes and rivers cradled within the ice itself. And, they have imaged thick basins of sediments under the ice, potentially containing the biggest water reservoirs of all. But so far, no one has confirmed the presence of large amounts of liquid water in below-ice sediments, nor studied how it might interact with the ice.

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.

“People have hypothesized that there could be deep groundwater in these sediments, but up to now, no one has done any detailed imaging,” said the study’s lead author, Chloe Gustafson, who did the research as a graduate student at Columbia University’s Lamont-Doherty Earth Observatory. “The amount of groundwater we found was so significant, it likely influences ice-stream processes. Now we have to find out more and figure out how to incorporate that into models.”

Scientists have for decades flown radars and other instruments over the Antarctic ice sheet to image subsurface features. Among many other things, these missions have revealed sedimentary basins sandwiched between ice and bedrock. But airborne geophysics can generally reveal only the rough outlines of such features, not water content or other characteristics. In one exception, a 2019 study of Antarctica’s McMurdo Dry Valleys used helicopter-borne instruments to document a few hundred meters of subglacial groundwater below about 350 meters of ice. But most of Antarctica’s known sedimentary basins are much deeper, and most of its ice is much thicker, beyond the reach of airborne instruments. In a few places, researchers have drilled through the ice into sediments, but have penetrated only the first few meters. Thus, models of ice-sheet behavior include only hydrologic systems within or just below the ice.

This is a big deficiency; most of Antarctica’s expansive sedimentary basins lie below current sea level, wedged between bedrock-bound land ice and floating marine ice shelves that fringe the continent. They are thought to have formed on sea bottoms during warm periods when sea levels were higher. If the ice shelves were to pull back in a warming climate, ocean waters could re-invade the sediments, and the glaciers behind them could rush forward and raise sea levels worldwide.

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.

In late 2018, a U.S. Air Force LC-130 ski plane dropped Gustafson, along with Lamont-Doherty geophysicst Kerry Key, Colorado School of Mines geophysicist Matthew Siegfried, and mountaineer Meghan Seifert on the Whillans. Their mission: to better map the sediments and their properties using geophysical instruments placed directly on the surface. Far from any help if something went wrong, it would take them six exhausting weeks of travel, digging in the snow, planting instruments, and countless other chores.

(See videos and images of the expedition)

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, said Key.

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.

However, the researchers say, if the ice surface were to thin—a distinct possibility as climate warms—the direction of water flow could be reversed. Overlying pressures would decrease, and deeper groundwater could begin welling up toward the ice base. This could further lubricate the base of the ice and increase its forward motion. (The Whillans already moves ice seaward about a meter a day—very rapid for glacial ice.) 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. But if that will happen, and to what extent, is not clear.

“Ultimately, we don’t have great constraints on the permeability of the sediments or how fast the water would flow,” said Gustafson. “Would it make a big difference that would generate a runaway reaction? Or is groundwater a more minor player in the grand scheme of ice flow?”

The known presence of microbes in the shallow sediments adds another wrinkle, say the researchers. This basin and others are likely inhabited further down; and if groundwater begins moving upward, it would bring up the dissolved carbon used by these organisms. Lateral groundwater flow would then send some of this carbon to the ocean. This would possibly turn Antarctica into a so-far unconsidered source of carbon in a world already swimming in it. But again, the question is whether this would produce some significant effect, said Gustafon.

The new study is just a start to addressing these questions, say the researchers. “The confirmation of the existence of deep groundwater dynamics has transformed our understanding of ice-stream behavior, and will force modification of subglacial water models,” they write.

The other authors are Helen Fricker of Scripps Institution of Oceanography, J. Paul Winberry of Central Washington University, Ryan Venturelli of Tulane University, and Alexander Michaud of Bigelow Laboratory for Ocean Sciences. Chloe Gustafson is now postdoctoral researcher at Scripps.

# # #

 Videos and images of the expedition


JOURNAL

Science

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

A dynamic saline groundwater system mapped beneath an Antarctic ice stream

ARTICLE PUBLICATION DATE

6-May-2022

From EurekAlert!

 

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Chris Hanley
May 8, 2022 2:41 pm

This would possibly turn Antarctica into a so-far unconsidered source of carbon in a world already swimming in 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 …

If they keep going something even more terrifying than carbon might emerge.

Last edited 1 month ago by Chris Hanley
Scissor
Reply to  Chris Hanley
May 8, 2022 2:51 pm

What’s more terrifying than carbon?

That’s sarcasm, BTW.

Patrick healy
Reply to  Scissor
May 8, 2022 11:30 pm

Maybe Carbon Dioxide.??

PCman999
Reply to  Scissor
May 8, 2022 11:33 pm

Godzilla
Frozen alien spacecraft
Just about anything else.

OTOH carbon is pretty scary when detected in your Christmas stocking.

Reply to  Scissor
May 9, 2022 11:45 am

And the fake article forgot to mention over 100 volcanoes under the ice … https://www.youtube.com/watch?v=raR5YgFcIQQ

Matt Kiro
May 8, 2022 2:50 pm

I thought all the science was settled?! Now they are telling me there are new things as yet unknown?

Bill Powers
Reply to  Matt Kiro
May 9, 2022 9:03 am

It is only settled if it is unsettling.

The debate is still over.

Rich Davis
Reply to  Matt Kiro
May 9, 2022 5:07 pm

Yes, but let’s not lose sight of a vitally important point. Everything that is as yet unknown—literally everything—is worse than we thought.

Rud Istvan
May 8, 2022 3:08 pm

That there is liquid groundwater in porous sediments under WAIS is utterly unsurprising. It is an active tectonic region with over a hundred mapped sub ice volcanos. Nice to be observationally confirmed

What is surprising is to somehow tie this new fact to possible global warming sea level rise tipping points, even remotely. The groundwater is there, more rapid ice shedding is not—even in the Amundsen Embayment (where there are for sure sub ice volcanos, because the eruptive ash can be seen in PIG ocean iceberg sluff faces).

gbaikie
Reply to  Rud Istvan
May 8, 2022 3:33 pm

Geothermal heat somewhat warms the very cold glacial ice

Marcus
May 8, 2022 3:26 pm

Well, no wonder the oceans are losing their minds …errr ummm….memory. Or was that the climate scientist ? I keep forgetting ! LOL

p.s. Anthony, why the “dog house” again ? The darn roof leaks….!

Last edited 1 month ago by Marcus
Chris Hanley
May 8, 2022 5:41 pm

However, the researchers say, if the ice surface were to thin—a distinct possibility as [if] climate warms—

Observations have shown little if any net warming in the Antarctic so far.

Rob_Dawg
May 8, 2022 6:42 pm

> “Many scientists say…”

Stopped reading.

Patrick healy
Reply to  Rob_Dawg
May 8, 2022 11:33 pm

I got to ‘how to incorporate that into models’ and soldiered on. Like you I should have stopped there.

RoHa
May 8, 2022 7:10 pm

“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,”

Some mistake, surely. This suggests that the ocean waters can’t reach that area now because there is too much ice, and there was less ice in the past. How can there be more ice now when the Earth is the hottest it’s ever been ever, and we are all going to fry in a couple of years?

PCman999
Reply to  RoHa
May 8, 2022 11:36 pm

That comment about a recent warmer past must have slipped past the political officer at the university.

Clyde Spencer
May 8, 2022 8:49 pm

This basin and others are likely inhabited further down; and if groundwater begins moving upward, it would bring up the dissolved carbon used by these organisms. Lateral groundwater flow would then send some of this carbon to the ocean.

So, in other words, there is natural, potential carbon sources under the ice, which have been sequestered temporarily, and will someday make it into the oceans regardless of what humans do.

Pat from kerbob
Reply to  Clyde Spencer
May 8, 2022 9:59 pm

But it will be our fault
Just because
We all know that

Chris Nisbet
May 8, 2022 10:14 pm

I’m not sure I could stand being a climate scientist. Every single new discovery or observation would fill my mind with thoughts about how it might cause even worse global warming. Nothing seems to give them any reason to think things might not be as bad as they first thought.
That’s how it seems these people think whenever I read one of these stories.

Jeroen B.
May 8, 2022 11:29 pm

“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.”

Stopped reading right there. Whatever valid conclusions they might have found are probably buried and twisted religiously correct.

Last edited 1 month ago by Jeroen B.
PCman999
May 8, 2022 11:31 pm

How do the polar glacial panickers get away with this crap about glaciers speeding up if the sea ice shelf breaks up or there is increased ground water underneath?

Correct me if I am wrong, but don’t glaciers retreat in a warming climate? They certainly don’t create extra ice such that huge sections break off the end when the growth exceeds the underlying support.

Right-Handed Shark
May 9, 2022 12:20 am

“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”

Really? What caused that warm period?

comment image

https://earth.org/data_visualization/a-brief-history-of-co2/

Last edited 1 month ago by Right-Handed Shark
Rich Davis
Reply to  Right-Handed Shark
May 9, 2022 5:13 pm

Heresy! There never was a warm or cold period. Hockey Stick! My fingers are firmly in my ears, I can’t hear you!!

fretslider
May 9, 2022 4:51 am

Could that meltwater have anything to do with the more than 138 volcanoes that have been identified throughout West Antarctica?

Not to mention a magma chamber…

peter schell
May 9, 2022 6:38 am

What is sad is that all the speculation is centered around the effect it might have on climate, even if they have to jump through hoops to arrive at the conclusions.

What should be garnering the most speculation is what it might mean in regards to finding life in places like Europa.

Steve Z
May 9, 2022 7:34 am

If there are microbes in the sediments below the ice, where does their food come from? There is no photosynthesis below the ice in total darkness, so is their food in organic material that drifts in from the sea surrounding Antarctica (if this is below sea level)? Or is it left over from a time when Antarctica was warmer than it is now, and possibly had ice-free summers?

Duane
May 9, 2022 7:50 am

It’s a well established fantasy of the warmunists that liquid water serves as a “lubricant” for glaciers. That is what ignoramuses, who don’t understand basic physics and engineering think, but it’s not what the actual engineers think who understand glaciers.

Glaciers move slowly because they are semi solid, and they don’t move faster due to so-called “lubrication” from liquid water, but rather they can move faster solely because of the laws of physics and hydraulic engineering. A glacier only moves at all because of gravity, otherwise they would stay put and never move at all. It is the elevation of the glacier surface between Point A and Point B that causes a glacier to move, and the greater the difference in elevations, or “head” as engineers call it, from upstream to downstream that determines the speed at which the glacier moves. A glacier can only move towards the sea when the surface elevation of the glacier upstream of the waters edge is higher than sea level. Meaning, a glacier only moves faster when there is MORE upstream ice accumulated to drive the flow downhill to the sea.

Gordon A. Dressler
May 9, 2022 9:31 am

Once again a peer-reviewed publication that features the action modifiers “could”, “possible” and “may”.

“Could” is found 9 times in the above article from Columbia Future Climate School in the context of future possibilities. And “possible”/”possibility” is found three times.

Peer-reviewing future options is NOT science-in-action.

I guess the authors didn’t chose to just stick to the headline topic “Scientists Discover a Giant Groundwater System” because they desperately need future funding for their “climate school”.

Sturmudgeon
Reply to  Gordon A. Dressler
May 9, 2022 4:06 pm

Your final ten words tell the tale.

May 9, 2022 4:26 pm

In recent years, researchers in Antarctica have discovered hundreds of interconnected liquid lakes and rivers cradled within the ice itself.”

Mountaineers have known about meltwater tunnels for many decades.

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.”

  • Hand dug holes in snow.
  • Limited amount of instruments.
  • Brief periods of use.
  • Sensors in snow or ice? Apparently, these researchers didn’t care.

They also reanalyzed natural seismic waves emanating from the earth that had been collected by another team, to help distinguish bedrock, sediment and ice.”

Collected separately, by a different team? Meaning there is zero foundation for their fantasies.

“However, the researchers say, if the ice surface were to thin—a distinct possibility as climate warms—the direction of water flow could be reversed. Overlying pressures would decrease, and deeper groundwater could begin welling up toward the ice base. This could further lubricate the base of the ice and increase its forward motion. (The Whillans already moves ice seaward about a meter a day—very rapid for glacial ice.) 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. But if that will happen, and to what extent, is not clear.

Waffle word highlighting, mine.

  • Five “could”s.
  • Three “if”s.
  • A “possibility”
  • Then a final admission that they do not really know.

That is a lot of waffle word speculation. The real conclusion to their research is that they had a great vacation in Antarctica and they feigned science in favor of fantasies.

Evan
May 9, 2022 6:57 pm

The largest ice flow feeds into the largest ice shelf, from the most volcanically active area of Antarctica. Of course it’s going to also be the fastest.

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