A mysterious hole the size of Switzerland is forming in the same place in Antarctica. After 50 years, experts found out the reason

Scientists have solved a 50-year-old mystery and announced that they have discovered what causes a hole the size of Switzerland to repeatedly form in Antarctic ice, according to Live Science.

Researchers first noticed the hole, called the Maud Rise polynya, in 1974 and 1976 in Antarctica’s Weddell Sea, and since then it has reappeared fleetingly and sporadically, each time with different sizes, although it forms in the same place. It also happened that for years this phenomenon did not take place. This has left scientists puzzled as to the exact conditions required for the hole to form.

In 2016 and 2017, a huge 80,000 square kilometer hole formed and remained that way for several weeks during both winters, allowing scientists to take a closer look at the phenomenon and finally solve the mystery 50 years old. They wrote about the discovery in the journal Science Advances.

“2017 was the first time we’ve had such a large and long-lasting hole in the Weddell Sea since the 1970s,” said lead author Aditya Narayanan, a researcher at the University of Southampton in England.

When summer turns to winter in Antarctica, the sea ice expands from about three million square km to 18 million square km, covering 4% of the Earth’s surface.

How it is formed

Holes in this ice, called polynyas, form when strong winds from within push the plates outward. This cold wind also freezes more seawater inside them, adding extra chunks to the ice sheet.

But in the open ocean and away from these coastal winds, where the Maud Rise forms, holes in the sea ice are much less likely to develop. This, along with a stunning reduction in the total extent of ice in the Southern Ocean, has led scientists to wonder what specific conditions could cause the formation of the Maud Rise.

To investigate the mystery, the scientists analyzed data from satellites, but also looked at previous observations made by other researchers. They found that in 2016 and 2017, the Weddell Sea’s circular ocean current, called the Weddell Gyre, was stronger than in other years, helping underwater currents bring salt and heat closer to the surface.

The hole is located near Maud Rise, an underwater mountain.

The new discovery is important for understanding Antarctica and its impact on the global ocean, according to the researchers. Climate change is already making winds on the southernmost continent stronger, likely creating more such holes in the future. Meanwhile, 40% of global ocean waters originate off the coast of Antarctica, making it vital in regulating regional climate across the planet.

Publisher: BC

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