The massive iceberg A23a, regarded as the largest and oldest in the world, has resumed its northward drift after being trapped in a rotating water column near the South Orkney Islands for several months. According to reports, this iceberg, weighing approximately one trillion tonnes and spanning an area twice the size of Greater London, had remained stationary in the Weddell Sea for over three decades before beginning its gradual movement in 2020. Recent developments indicate it is now being carried by the Antarctic Circumpolar Current, potentially directing it towards South Georgia.
Caught in an Oceanographic Phenomenon
As per a report by BBC, scientific observations have revealed that the iceberg was recently caught in a Taylor Column, a phenomenon where rotating water above an underwater seamount prevents objects from moving freely. This occurrence stalled A23a's anticipated drift northwards. As per Dr Andrew Meijers, an oceanographer at the British Antarctic Survey (BAS), this change in movement is significant for ongoing studies. Speaking to the BAS, he mentioned that the team is keen to track whether A23a will follow the same path taken by other large Antarctic icebergs and assess its impact on marine ecosystems.
Impact on the Southern Ocean Ecosystem
Researchers aboard the British Antarctic Survey vessel RRS Sir David Attenborough have been monitoring A23a to understand its effects on local ecosystems. Data collected as part of the BIOPOLE project is being used to investigate the iceberg's influence on nutrient distribution and carbon cycles. According to Laura Taylor, a biogeochemist involved in the study, in a statement, these large icebergs often enrich waters they pass through, promoting biodiversity in otherwise barren areas. She highlighted that further analysis would focus on how an iceberg's origin and size affect these processes.
Reports suggest that as A23a approaches warmer waters near South Georgia, it will likely fragment into smaller icebergs and eventually melt, providing crucial insights into its environmental role.
