The mysterious ice circles on Lake Baikal, visible from space, have puzzled researchers for decades.
Scientists from Russia may have finally found a satisfactory answer to the enigmatic series of ice circles on Lake Baikal, the deepest lake in the world, in Siberia.
Siberia is home to countless mysteries. Not only is it home to caves that our ancient ancestors known as the Denisovans once inhabited, leaving behind intricate tools and jewelry fragments, Siberia is also known for countless discoveries of frozen, long-extinct animal species.
In addition to that, Siberia is also known to one of the largest freshwater lakes on the surface of the planet; Lake Baikal.
The massive Lake contains 22–23% of the world’s fresh surface water with 23,615.39 km3 (5,670 cu. mi) of fresh water, it contains more water than the North American Great Lakes combined. In addition to that, with a depth of 1,642 m (5,387 ft), Lake Baikal is also the world’s deepest lake.
Its incredible characteristics don’t stop there though. It is also considered one of the clearest and oldest lakes on the surface of the planet, estimated to be between 25—30 million years old. In terms of surface area, it is the seventh-largest lake in the world.
In addition to all of the above, Lake Baikal is home to a series of strange, enigmatic circles in the Ice, scientists have not been able to explain for years. Several theories and myths have since surfaced, but no logical explanation has ever been given.
That is until now.
Around twenty years ago, scientists realized that ice circles formed in different places on Lake Baikal in the spring and summer months. The mysterious circles were so large that they could only be seen from airplanes or satellites.
The initial suspicion was that they formed due to methane bubbling from below. But the tests showed no methane deposits under the lake. This deepened the mysteries surrounding the ice circles.
Who or what created these odd shapes in the ice? The ice circles that have been observed have appeared in different sizes and different locations, but all are characterized by a bright center surrounded by a dark circle.
The circles were also quite large in diameter.
Previous research has shown that ice circles had an average diameter between 5 to 7 kilometers.
The circles remain on the ice from a few days to a few months and eventually disappear.
Additional research showed that similar ice circles were not exclusive to Lake Baikal: some were seen in Mongolia, on Lake Hovsgol and others on Lake Teletskoye in Russia.
Studies of different lakes suggested that the enigmatic ice circles probably appear in most of the deep lakes that freeze during winter.
But there was still no explanation of how they formed.
Determined to find the answer, the authors of the new study, published in the journal Limnology and Oceanography and led by Alexei V. Kouraev, from Tomsk State University – traveled to Lake Baikal several times during the winters of 2016 and 2017.
On each expedition, they drilled holes in the ice and placed sensors in the lake where the circles formed.
They also studied infrared satellite images that revealed temperature variations in the lake.
In February 2016, the team found a possible clue: a swirl had formed in the water below the ice circle, and the water in the whirlpool was a couple of degrees hotter than the water around it.
The researchers suggest that ice circles are formed due to water movement and temperature differences with the surrounding water due to swirling.
The following year, the team found another whirlpool, this one without a circle on top. They suggested that they had seen the whirlpool before a circle formed on top. However, they could not explain why the whirlpools were forming.
One mystery solved, another one waiting to be revealed.
Baikal continues to provide more questions than answers.