Study: Antarctica's "Achilles' Heel" Ice Sheet Once Collapsed

By Joseph Calamia | September 1, 2010 5:38 pm

West-antarcticaSimilar populations of seabed-rooted animals separated by 1,500 miles of ice, researchers say, could mean that the West Antarctic Ice Sheet was once a trans-Antarctic seaway. This surprising find has also led researchers to wonder if a warming planet could again cause the thick ice sheet to collapse and give way to a swath of open water.

The team, which published their study in Global Change Biology, found similar but separated bryozoans–creatures also called moss animals–in both the Ross and Weddell Seas while conducting the Census of Antarctic Marine Life. Given that bryozoans don’t move all that much, lead author David Barnes suggests that the isolated populations came from the same, connected habitat.

“Because the larvae of these animals sink and this stage of their life is short–and the adult form anchors itself to the sea bed–it’s very unlikely that they would have dispersed the long distances carried by ocean currents,” Barnes said. “Our conclusion is that the colonization of both these regions is a signal that both seas were connected by a trans-Antarctic sea way in the recent past.” [Wired]

If that’s the case, Barnes says, this past disappearance of the mile-thick ice sheet, possibly as recently as 125,000 years ago, hints at the West Antarctic Ice Sheet’s fragility. Calling the ice sheet Antarctica’s “Achilles’ Heel” in a press release, he says it might not withstand a warming planet.

“The most likely explanation of such similarity is that this ice sheet is much less stable than previously thought and has collapsed at some point in the recent past,” he told Reuters. “And if the West Antarctic ice shelf has been lost in recent times we have to re-think the possibility of loss in future with climate change,” he said. [Reuters]

Studying how Antarctica’s geography has changed in the past may give researchers a better understanding of how sea levels will change if the sheet melts.

“[B]ecause any collapse will have implications for future sea level rise, it’s important that scientists get a better understanding of big deglaciation events,” Barnes said. Scientists estimate that a complete collapse of the West Antarctic Ice Sheet would raise global sea levels by around 11 to 16 feet (3.3 to 5 m). “This biological evidence is one of the novel ways that we look for clues that help us reconstruct Antarctica’s ice sheet history,” Barnes said. [Live Science]

Related content:
80beats: Antarctic Sea Ice Grows Despite Global Warming—But It Won’t Last
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80beats: An Iceberg the Size of Luxembourg Breaks Free from Antarctica
DISCOVER: The Ground Zero of Climate Change
DISCOVER: Antarctica’s Hot Spot
DISCOVER: The Coolest Science Experiments in Antarctica (gallery)

Image: Wikimedia

CATEGORIZED UNDER: Environment, Living World
  • OnTheSun

    Either the mammals of those days were using wood-burning engines in their cars to escape hungry beasts, or the Earth’s magnetic poles moved, or the sun flashed us a big one for an extended period of time, or a super volcano blasted up nearby, or some space debris splashed down inconveniently. There may be other explanations for the biological evidence at diverse locations. Perhaps they were not concurrent. What a difference ten years can make, consider northern Europe in 1299ad and in 1319ad.

  • cgray451

    For the love of God, will someone stop Glenn Beck!!!!!!!

  • Nemesis


    “Perhaps they were not concurrent. What a difference ten years can make, consider northern Europe in 1299ad and in 1319ad.”

    That would be 20 years, my friend.

    I am interested in what changed in the 20 years you mentioned, but there’s no link.

  • Chicken Little

    When are we going to present the oil, gas and coal industries with the full cleanup bill, for the air, the soil and the water to be put back to the way it was before they showed up?


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