Scientists uncover secrets of enormous hole in Antarctic sea ice

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In 2016 and 2017, researchers observed an extraordinary event in Antarctica: a massive hole, called a polynya, formed in the sea ice, reaching a size nearly twice that of Wales.

This phenomenon puzzled scientists for years, but now, a study published in Science Advances sheds light on how this unusual opening in the ice was created and sustained.

The polynya, named after the submerged mountain-like feature Maud Rise in the Weddell Sea, was a rare occurrence, given that it appeared in the open ocean, far from the coastline where such openings are more common.

Scientists from the University of Southampton, the University of Gothenburg, and the University of California San Diego collaborated to investigate this intriguing event.

Through a combination of satellite observations, data from autonomous floats, and computational models, the researchers discovered a complex interplay of factors contributing to the formation of the polynya.

They found that strong winds, ocean currents, and the unique underwater geography played crucial roles in transporting heat and salt towards the ocean surface.

One key finding of the study was the importance of a process called “Ekman transport” in sustaining the polynya.

This process involves water movement driven by winds, which influences ocean currents. As the Weddell Sea current flowed around Maud Rise, turbulent eddies carried salt to the surface, contributing to the formation of the polynya.

Polynyas are not just large holes in the ice—they play a significant role in transferring heat and carbon between the ocean and the atmosphere. They can affect regional climate patterns and even influence global ocean circulation.

The researchers emphasized that understanding the mechanisms behind polynya formation is crucial for accurately modeling climate and ocean dynamics.

The study also highlighted the broader changes occurring in the Antarctic environment. Observations show a negative trend in sea ice extent since around 2016, marking a departure from the relatively stable conditions observed in previous decades.

The processes driving the formation of polynyas, such as upwelling of deep, salty water, may contribute to this trend.

By unraveling the mysteries of the Maud Rise polynya, scientists have gained valuable insights into the complex interactions shaping Antarctica’s environment.

This research underscores the importance of continued monitoring and study of polar regions to better understand their role in global climate systems.

Source: University of Southampton.