Giant, Mysterious Holes Have Appeared On Antarctica's Surface And Now Scientists Know Why

A mysterious phenomenon has been occurring every once in a while over Antarctica's surface that has baffled scientists and reporters alike. Massive holes would inexplicably appear on the icy surface, exposing the freezing waters beneath the floating island.

These gaps, known as polynyas, are common across Antarctica. Polynyas, which is Russian for “hole in the ice” can form either on shores or further inland. These holes can last between weeks to months and are also helpful for penguins, seals, and whales, allowing them gaps to pop-up to the surface and breathe.

However, the polynyas in the Wendell Sea area is peculiar. The first time a hole was discovered in the Wendell Sea area was in 1974. Satellite images revealed that the hole was the size of New Zealand. Researchers discovered that from 1974 to 1976, this entire gap remained ice free through three of the harshest Antarctic winters.

A new study conducted by researchers at the University of Washington discovered why these mysterious holes appear and what their existence could mean to ocean circulation.

“We thought this large hole in the sea ice — known as a polynya — was something that was rare, maybe a process that had gone extinct. But the events in 2016 and 2017 forced us to reevaluate that,” the study's lead author Ethan Campbell, a UW doctoral student in oceanography, said in a statement. “Observations show that the recent polynyas opened from a combination of factors — one being the unusual ocean conditions, and the other being a series of very intense storms that swirled over the Weddell Sea with almost hurricane-force winds.”

The new research indicates that when winds surrounding Antarctica draw close to the island's shore, it causes strong reactions in the Wendell Sea. An underwater mountain in the region, known as Maud Rise can cause spinning vortexes in the water. Researchers discovered that when the sea is especially salty, as it was in 2016, winter storms can cause the warm water to rise to the surface and be chilled by the freezing winds. This circulation feedback loop prevents sea ice from forming.

“This study shows that this polynya is actually caused by a number of factors that all have to line up for it to happen,” said co-author Stephen Riser, a professor of oceanography at the University of Washington. “In any given year you could have several of these things happen, but unless you get them all, then you don’t get a polynya.”

“Right now people think most of the bottom water is forming on the Antarctic shelf, but these big offshore polynyas might have been more common in the past,” Riser added. “We need to improve our models so we can study this process, which could have larger-scale climate implications.”