Indian scientists uncover 250-year history of Antarctica's mysterious 'hole'

Indian scientists have reconstructed the 250-year history of a mysterious area of open water that repeatedly appears in the sea ice around Antarctica, revealing that major openings have occurred several times in the past, including events comparable to one of the largest openings ever observed.

The study, published in The Cryosphere, was led by researchers from the National Centre for Polar and Ocean Research (NCPOR), Ministry of Earth Sciences, along with scientists from Denmark and Norway. The team used an Antarctic ice core to trace the history of the Maud Rise Polynya, a large area of open ocean surrounded by sea ice.

A polynya is essentially a large patch of open water that forms within an otherwise ice-covered ocean. The Maud Rise Polynya is located in the Weddell Sea, where it can dramatically alter the exchange of heat between the ocean and atmosphere. (Photo: Nasa)

The Maud Rise Polynya is located in the Weddell Sea, where it can dramatically alter the exchange of heat between the ocean and atmosphere.

The researchers drilled a 122-metre-long ice core from Djupranen Ice Rise in East Antarctica. Layers of snow and chemicals preserved inside the ice provided clues about conditions in the surrounding ocean and atmosphere over hundreds of years. The core was analysed at NCPOR in Goa.

The researchers were able to reconstruct the history of the Maud Rise Polynya back to 1774. Their analysis identified 25 years with evidence suggesting polynya activity, including three major events comparable to the large 1974-76 opening.

The 1974-76 event was particularly significant. At its peak, the open-water area exceeded 3,00,000 square kilometres. Another large opening occurred during 2016 and 2017, when the polynya expanded to more than 40,000 square kilometres.

These openings matter because they expose relatively warm ocean water directly to the cold Antarctic atmosphere.

This allows heat to escape from the ocean and can trigger large-scale movement of deep ocean water, potentially affecting ocean circulation and the climate around Antarctica.

The study found that major polynya events appeared in clusters rather than at regular intervals, suggesting that their formation depends on a particular combination of atmospheric conditions and ocean conditions.

The researchers said the 250-year reconstruction provides a longer perspective on the phenomenon and could help scientists understand what causes these rare openings and how they influence Antarctica's climate.- EndsPublished By: Sibu Kumar TripathiPublished On: Sep 21, 2026 15:53 IST