Since its initial discovery in the 1970s, the Maud Rise polynya has exhibited an enigmatic pattern, appearing and disappearing erratically in different sizes. This has challenged scientists to pinpoint the precise conditions necessary for its formation. However, extensive research conducted in 2016 and 2017, when the polynya reached an unprecedented size of 309,000 square miles, provided crucial insights into its genesis.
Analysis of satellite data, autonomous floats, tagged marine mammals, and previous observations revealed a complex interplay of factors at work. During these years, the Weddell Gyre, a circular ocean current in the Weddell Sea, was exceptionally strong. This intensified current facilitated the upward transport of salt and heat from deep ocean layers towards the surface. The Maud Rise polynya is situated near an underwater mountain called the Maud Rise. The stronger current caused salt to accumulate around this seamount, while surface winds created a corkscrew effect that brought the saltier water to the surface. This elevated salt concentration lowered the freezing point of the surface water, allowing the Maud Rise polynya to form and persist.
This discovery has significant implications for our understanding of Antarctica and its impact on the global ocean. Climate change is leading to stronger winds from Antarctica, potentially increasing the frequency and size of polynyas in the future. Furthermore, the formation of dense waters in polynyas plays a crucial role in regulating regional and global climates by influencing ocean currents and heat transport.
The research team highlights the importance of continued monitoring and research to unravel the complexities of Antarctica’s sea ice dynamics and their far-reaching effects on the Earth’s climate system.
