An expedition constituting a group of NASA scientists saw something puzzling while flying over the Beaufort Sea on April 14. They spotted three holes in the sea ice and rings around them with some distinctive wavy ice to their top left. The sea is located north of Alaska at the Canadian border.
John Sonntag, a meteorologist with NASA who took the above photo, said in a statement: “We saw these sorta-circular features only for a few minutes today. I don’t recall seeing this sort of thing elsewhere.”
Scientists are however saying that although the figures might resemble an icy equivalent to crop circles, there might just be a simple explanation for the phenomenon.
“It’s definitely an area of thin ice, as you can see finger rafting near the holes and the color is gray enough to indicate little snow cover,” said IceBridge project scientist Nathan Kurtz, according to NASA. “I’m not sure what kind of dynamics could lead to the semi-circle shaped features surrounding the holes. I have never seen anything like that before.”
Walt Meier, an atmospheric scientist at the National Snow and Ice Data Center who specializes in sea ice, said, “My first guess is that these are seal breathing holes.” Such holes have previously been known to be made by Harp and ring seals on thinner Arctic sea ice. They use these holes to come up for air whenever they need.
That being said, we need to have a good explanation as to why the sea ice in this vicinity is thin enough for the seals to dig through for this theory to hold. According to Meier, these holes could be due to warmer water that comes in from the Mackenzie delta which is quite nearby.
The delta is a shallow outpouring of the Mackenzie river along the nearby Canadian coast. He explains that warmer water from the river flows into the ocean, and because of its lower density, it floats to the surface in plumes.
Because of this, the warmer water is able to thin out the ice at the surface, luring seals to a region where the ice is already thin and it is easier for them to break through. As for the wavy formations near the said holes, scientists propose that this could be due to warm water sloshing over the edges of the holes while rising from them.
However, the holes are, as of now, nothing more than a spectacle and don't tell us much about the sea environment in the Arctic. But Meier says that the phenomenon does highlight a trend in sea ice in general.
The photo shown below marks an evidence of another phenomenon called "finger rafting", in which two ice sheets are pushed together by the wind causing them to overlap. Meier says that the most probable explanation for this is higher Arctic temperatures in recent times.
Before the 1980s, he says, the sea ice formed in the area would be strong enough to bear southern winds that blow north at the start of winter. But due to relatively warmer waters, the ice now tends to be less solid and is vulnerable to the strong winds. Over the winter the water that is exposed freezes to form thin sheets and not thick layers of ice.
Having said that, for now, even as experts attempt to explain what they are, the holes remain a mystery.
According to NASA, Chris Shuman, who is a glaciologist at the University of Maryland at Baltimore County, said:
“This is in pretty shallow water generally, so there is every chance this is just ‘warm springs’ or seeps of groundwater flowing from the mountains inland that make their presence known in this particular area. The other possibility is that warmer water from Beaufort currents or out of the Mackenzie River is finding its way to the surface due to interacting with the bathymetry, just the way some polynyas form.”
When these thin sheets are blown together it results in the "finger rafting" phenomenon. These sheets are also likely to be susceptible to melting due to warm water coming in from the shores. Meier then says: “In recent years, how often that happens and the scale of [this pattern] is much more than it used to be."
While it may seem far-fetched to connect just one data point to climate change or the warming of Arctic sea waters, the photo does suggest that a trend of diminishing ice could be inferred from further research.