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A huge Antarctic lake has mysteriously vanished, taking with it double the volume of San Diego Bay as it disappeared into the ocean. Researchers witnessed its demise from satellite imagery before and after the 600–750 million-cubic-meter (21–26 billion cubic feet) lake drained through the ice shelf below, and believe it could tell scientists a lot about the stability of large bodies of ice in the region.
All that remains is the fractured covering of ice and a crater where the lake once stood.
Although the researchers aren’t exactly sure how the lake vanished in such a short amount of time, the most likely scenario is the bottom of the lake fracturing under the intense pressure. Their research was published in the journal Geophysical Research Letters.
“We believe the weight of water accumulated in this deep lake opened a fissure in the ice shelf beneath the lake, a process known as hydrofracture, causing the water to drain away to the ocean below,” said lead author Roland Warner, a glaciologist with the Australian Antarctic Program Partnership at the University of Tasmania, in a statement.
Situated pointing towards the South Indian Ocean, the Amery Ice Shelf is the third-largest shelf in Antarctica, with some areas reaching 1,800 meters (5,900 feet) thick. This lake was situated on top of the Amery Ice Shelf, at a place where the ice is more like 1,400 meters (4,590 feet) thick. It is not uncommon to see lakes drained through hydrofracture, and indeed scientists have identified many ice shelves within Antarctica that may be vulnerable to it, but it is not expected to happen in such high ice depth.
Now, the researchers hope to use this information, along with state-of-the-art satellites that were able to capture the lake’s grizzly demise (aptly named ICESat-2), to further their understanding of the degradation of ice shelves in Antarctica.
“It is exciting to see ICESat-2 show us details of processes that are occurring on the ice sheet at such fine spatial scale,” said co-author Helen Amanda Fricker, a glaciologist at Scripps Institution of Oceanography, said in a statement.
“Since surface meltwater on ice shelves can cause their collapse which ultimately leads to sea-level rise when grounded ice is no longer held back, it’s important to understand the processes that weaken ice shelves.”
While the edges of Antarctica – along with the rest of the world – are currently experiencing unprecedented heat, the researchers can’t conclude that climate change is responsible at this time. It would certainly make sense, as even the most inhospitable places on Earth are feeling the heat, with the Arctic Circle experiencing temperatures as high as 48 °C recently.
