The cause of the sinking of the Antarctic lake is a big question for scientists

The ice basin is a “doline” – a term meaning land that was depressed and then naturally closed. Usually a drain hole. The ice doline measures about 11 square kilometers and contains some of the remnants of the ice cap cracks that once existed above the lake. Doline is a small lake and is about half the size of Lake Minnewanka in Alberta, or 12 times the size of Lake Louise.

According to reports from Scripps Institution of Oceanography. The doline contains about 600-750 million cubic meters of water, about twice the volume of San Diego Bay. This amount far exceeds the amount of meltwater.

The loss of such a large lake makes a difference to the height of the ice sheet itself. The researchers used a laser instrument on NASA’s ICESat-2 to calculate the precise elevation change caused by the lake’s drainage.

Helen Fricker, a professor at the Scripps Institution of Oceanography, said ICESat-2 orbits with exactly repeating earth tracks and compares elevations before and after the lake is drained. Then show the dramatic vertical scale of the disturbance.

“After the lake dries, the ice sheet area rises with the ice sheet surface as high as 36 meters around the lake. Loss of lake water will reduce the weight of the floating ice sheet so that ocean pressure lifts it to the doline,” said Warner.

The lake itself sinks deeper into the shoal, with a hollow basin found 80 meters below the lake’s surface. Satellite photos of the lake showing before and after processes show how the ice sheet moves, also creating new, smaller pools of water where the water used to flow and moving away from the lake with the surface appearing to crack and recede.

Warner revealed there is a possibility that the doline could be filled with water again. Or hydrofracture can open again and drain the water again.

Although this phenomenon is not associated with the impact of climate change. However, the movement of ice sheets at the edges of regions such as Antarctica remains to be explored further. Considering the loss of the ice sheet or the cracking of the ice sheet away from the continent. Thus, the natural reaction can accelerate the loss of ice on the mainland itself. This will trigger sea level rise.

Reporter: Ruth Flowers

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