World’s largest iceberg has been orbiting a whirlpool for months

A23a is known as the largest iceberg in the world and broke away from the Firchner-Ronne Ice Shelf in Antarctica in August 1986. After this breakup, the iceberg remained stable for about 34 years and began to move towards the western Weddell Sea with the ocean currents in 2020.

However, the iceberg that got caught in the vortex during its journey has been spinning around it since the beginning of this year. While some experts believe this situation will prevent the iceberg from moving towards warmer waters and slow its melting, others say the spinning motion will accelerate the melting.

British Antarctic Society (BAS) Polar Oceans Team Vice President Dr. Kate Hendry and Head of the Department of Physics, Oceanography and High Oceans Dr. Alexander Brearley said the calving of iceberg A23a from the Filchner-Long Ice Shelf was a natural process and had nothing to do with the climate crisis.

The scientists noted that A23a will remain in the cold water until early 2024, losing a small portion of its area in the process, from 300,850 square kilometers to 300,672 square kilometers. The scientists noticed that the iceberg began to rotate north of the South Orkney Islands:

“A23a is currently rotating counter-clockwise at a rate of about 15 degrees per day just north of the South Orkney Islands. This rotation is due to the iceberg being in a small-scale circulation known as the Taylor column, which sometimes occurs when ocean currents pass over underwater mountains.” “A23a is currently located on a mountain called Pirie Bank, which is 100 kilometers wide and 1,000 meters deep.”

“We think that the rotation process alone cannot prevent iceberg melting, but that this motion can prevent the icebergs from moving in the warmer direction,” the researcher said, assessing the change in melting rate due to the circulation in which the icebergs are trapped. Melting in northeastern waters will be relatively slow until the icebergs are no longer circulating. “Made his assessment.

May harm seafloor life

Scientists cautioned that while they don’t know how long the iceberg will stay there, another iceberg with similar features was trapped in the same circulation for four years. “This iceberg is obviously dangerous to maritime shipping, but we are lucky that it has been trapped in the same circulation.” Satellite imagery has carefully examined the situation, “which means fishing, research and cruise ships can plan safe routes to avoid the iceberg,” he said.

The researchers say the massive icebergs could stir up the ocean floor, releasing more nutrients and carbon for organisms in the area, but could also harm life on the seafloor.

The researchers stressed that while the A23a iceberg is not currently causing any erosion to the seafloor, there is always concern about giant glaciers in the Antarctic region hitting the seafloor, and stressed that such a situation could have a negative impact on the feeding and migration processes of large animals such as seals, penguins and whales.

“Spinning it helps it melt faster”

UC Earth System Science lecturer Prof. Dr. Eric Rignot commented that icebergs melt faster when they are swirling in a vortex.

Drawing attention to the effect of rotational motion on the melting rate of icebergs, Rignot said: “Rotation and rapid motion contribute to faster melting, since greater heat exchanges are generated in the ocean. Therefore, it is likely that the iceberg will begin to break up faster and into smaller fragments,” shared his opinion.

Rignot said the melting of the iceberg has nothing to do with climate change. “The first reason it melts is that it is in a warmer and saltier environment. The fate of all icebergs drifting in the sea is to eventually melt,” he said.

Rignot said A23a’s rotation is due to the ocean’s circulation mechanism, and he said the iceberg is huge and has a large moment of inertia, so it could continue to rotate in this way for many years.

“He will maintain his position for a long time”

The professor is the chairman of TÜBıTAK Marmara Research Center (MAM) and the coordinator of the 4th National Arctic Scientific Research Expedition and ensures that Turkey’s work in the polar region is recognized at the national and international levels. Dr. Burcu Özsoy said that the A23a iceberg being caught in the vortex means that the iceberg will move for a period of time according to the strength and direction of the vortex.

Sharing information that A23a was caught in a vortex after being split into two different currents due to an obstacle, Ozsoy said: “In this arrangement, considering the depth of A23a below the sea surface, it will remain in its current position for a long time before it melts or gets hotter. “This means that it will protect these areas and not pass through,” he concluded.