The A23a iceberg, measuring 3,800 square kilometers (1,500 square miles) and 400 meters (1,312 feet) thick, has resumed movement after being trapped in a vortex for most of the year. This iceberg is more than twice the size of Greater London.
Originally breaking free from Antarctica in 1986, A23a became lodged on the seabed of the Weddell Sea, part of the Southern Ocean, where it remained static for over 30 years. In 2020, it began moving northward but became caught in a rotating column of water near the South Orkney Islands.
On December 14, 2024, the British Antarctic Survey (BAS) confirmed that A23a is now drifting further north. Dr. Andrew Meijers, an oceanographer at BAS, expressed excitement at the iceberg's movement, noting the interest in its potential path compared to other large icebergs that have calved off Antarctica.
A23a is expected to eventually exit the Southern Ocean and enter the Atlantic Ocean, where it will encounter warmer waters, leading to its fragmentation into smaller icebergs and eventual melting.
The BAS is studying the ecological impact of icebergs on local ecosystems as they drift through these waters. Previous research, including data collection by the RRS Sir David Attenborough, has indicated that large icebergs can provide essential nutrients to surrounding waters, fostering thriving ecosystems in less productive areas.
Current research aims to understand how the size and origin of specific icebergs influence these ecological processes.