The A23a iceberg, the largest and oldest in the world, has started to move after being stuck for decades. This colossal ice mass, measuring 400 meters thick, weighs nearly one trillion tons, and spans an area of approximately 3,600 square kilometers—larger than two cities of São Paulo—has freed itself from its position north of the South Orkney Islands and is now drifting in the Antarctic Ocean.
The journey of this giant iceberg began in 1986 when it broke away from the Filchner Ice Shelf in Antarctica, where it remained lodged on the seafloor of the Weddell Sea for over 30 years, as reported by the British Antarctic Survey.
In 2020, A23a began moving northward. Since then, its journey has been marked by intriguing scientific events. One notable occurrence was its entrapment in a phenomenon known as the Taylor Column, which is a rotational water movement that keeps objects stationary while they spin around.
Recently, the iceberg escaped from this column and is now heading north along the Antarctic Circumpolar Current. Scientists predict that it may reach the subantarctic island of South Georgia, where the warmer waters are expected to cause it to break into smaller icebergs and eventually melt.
Oceanographer Andrew Meijers from the British Antarctic Survey expressed excitement at witnessing A23a's movement after its long stagnation, noting interest in whether it will follow the same path as other large icebergs that have detached from Antarctica, and the potential impact on the local ecosystem.
Biogeochemist Laura Taylor, involved in a scientific expedition to study A23a, highlighted that the iceberg could provide nutrients to the surrounding waters, fostering prosperous ecosystems in otherwise less productive areas.
Research efforts include collecting surface water samples from the ocean behind, adjacent to, and ahead of the iceberg's path to determine the types of life that may form around A23a and its effects on carbon balance in the ocean and atmosphere.