Scientists solve the mystery of huge hole in Antarctica that baffled experts for eight years

When a hole that's supposedly the size of Switzerland suddenly appears in the ice in Antarctica's Weddell Sea, you can imagine it's the sort of thing which really rallies scientists together.

Despite the brightest boffins in the world taking a look at it, everyone has been baffled by the massive and mysterious opening for the best part of a decade - until now.

Eight years after it appeared in a chunk of Antarctica's icy armour, it seems that experts have now finally come up with an answer about how it happened.

In 2016, no one had a clue what to do when the hole - which is twice the size of Wales - suddenly formed in the ice.

It was regarded as what is known scientifically as a polynya, which describes a large, naturally occurring area of open water surrounded on all sides by sea ice.

So after it cropped back up eight years ago, scientists made it their mission to get to the bottom of what was causing it.

Teams carried out extensive studies using various impressive techniques, such as fitting sensors to small helmets that seals wore to test the waters in the area - but good old satellite imaging and computer models came in handy too.

They plotted out the area of the Weddell Sea, where there is a submerged mountain called Maud Rise, to try and work out the reason for the confusing hole phenomenon which was first spotted in the 1970s - and had grown five times the size by the time it was seen again more than four decades later.

Basically, after intense research and wrestling with seals to get helmets on them, boffins came to the conclusion that the unusual hole as being formed by a process called 'Ekman transport'.

The huge hole appeared in the ice in Antarctica's Weddell Sea in 2016. (NASA Earth Observatory)

Alberto Naveira Garabato of the University of Southampton in the UK, who was part of the research team, explained: "Ekman transport was the essential missing ingredient that was necessary to increase the balance of salt and sustain the mixing of salt and heat towards the surface water."

In a nutshell, Ekman transport refers to the movement of different layers of water around the ocean, which is often caused by the wind on the surface interacting with massive bodies of liquid below it.

This sometimes combines with already existing currents to push warmer water up towards the surface in the Maud Rise area, and when the conditions are right it results in that huge hole forming.

As we mentioned earlier, this is known as a 'polynya'.

Since these often don't stay around for very long, studying them can be a real challenge, but scientists really managed to make the most of the time they had with the Maud Rise polynya in 2016 and 2017.

Scientists reckon they've discovered the reason behind the phenomenon (Getty stock photo)

Researchers reckon that a specific circular current, known as the Weddell Gyre, was responsible for ripping a huge hole in the ice in this case.

They explained that it brought warm and salty water to the surface after a prolonged period of powerful currents over a three year period from 2015 to 2018.

Professor Fabien Roquet, of the University of Gothenburg, said of the finding: "This upwelling helps to explain how the sea ice might melt.

"But as sea ice melts this leads to a freshening of the surface water, which should in turn put a stop to the mixing. So, another process must be happening for the polynya to persist. There must be an additional input of salt from somewhere."

Professor Sarah Gille, of the University of California San Diego, added: "The imprint of polynyas can remain in the water for multiple years after they’ve formed.

"They can change how water moves around and how currents carry heat towards the continent. The dense waters that form here can spread across the global ocean."