In the spring of 2024, a colossal polynya the size of Switzerland began to appear and then disappear in the middle of Antarctica.
Researchers checked archival data and realized that they tried to explain this phenomenon half a century ago – there were no apparent reasons for the existence of a sporadic failure, but now scientists have managed to find the missing piece of this strange Antarctic mystery.
The Maude Rise polynya is a giant crack in the sea ice. Open water is supported by currents and wind, but in such cases the sinkholes remain open. Maude Rise has been disappearing and reappearing since the last century.
In the archives, researchers found information that the failure was first seen on satellite images in 1974. At that time, Maud Rise was larger than Great Britain. The hole appeared several winters in a row.
But since 1970, the polynya began to form only sporadically, and remained only for a short period of time. In 2016 and 2017, Maud Rise began to grow again, then it appeared in 2024, which allowed researchers to find a solution to the mystery.
It turned out that in those same years the ocean current in the Weddell Sea was stronger than usual. Its turbulent whirlpools lift huge columns of warm salty water to the surface. Strong winds blowing over the ocean surface pushed the salt away, preventing new ice from forming.
Current and wind bring here an additional influx of salt from the ocean. Therefore, the polynya grows as the current increases, and then becomes smaller, says Fabien Roquet, a member of the research team.
Wormwood will be studied over the next few years. Scientists are concerned that its formation could also be influenced by climate change.
