Antarctica's ephemeral giant. The enigma of the Maud Rise polynya solved

The Maud Rise polynya, an anomaly that has appeared sporadically in Antarctica since the 1970s, has long intrigued researchers who wanted to solve its mystery. It seems that experts have finally managed to do so, as reported in the pages of Science Advances. At the turn of 2016 and 2017, the hole persisted in the Weddell Sea for several weeks and was as large as Switzerland, facilitating research on it.

According to Live Science, scientists first noticed the mysterious hole in Antarctica's sea ice in 1974 and 1976 in the Weddell Sea. Since then, researchers have observed its sporadic returns. However, it never appears in the same place and varies in size, making it difficult to study precisely.

Only at the turn of 2016 and 2017, when the Maud Rise Polynya opened up for several weeks, and its size reached about 30,888 square miles, were scientists from the University of Southampton, the University of Gothenburg, and the University of California, San Diego able to take a closer look and solve the mystery behind it.

The analysis's results, published in the scientific journal "Science Advances", reveal the key process responsible for the appearance of the polynya. As the researchers determined, the hole appears due to complex interactions between the wind, ocean currents, and the unique geography of the ocean floor, which transport heat and salt toward the surface.

Thanks to observations from autonomous floats, tagged marine mammals, and modeling, scientists discovered that the most recent occurrence of the polynya, which was as large as Switzerland, was additionally driven by an ocean current in the Weddell Sea. At the turn of 2016 and 2017, it was stronger than usual, causing more saline and simultaneously warmer water to flow into the polynya area.