Megaiceberg breaks off and drifts in the Southern Ocean

Madrid. After spending decades stranded on the seabed, mega iceberg A23a has broken free from its position north of the South Orkney Islands and is now drifting in the Southern Ocean.

The A23a colossus, which at 3,000 square kilometers is twice the size of Greater London and weighs almost a trillion tonnes, broke off from Antarctica’s Filchner Ice Shelf in 1986 and remained stranded on the Weddell seabed for more than 30 years before. to begin its slow journey north in 2020.

The iceberg’s journey has been marked by intriguing scientific events. For months, it was trapped in a Taylor plume, an oceanographic phenomenon in which rotating water on a seamount traps objects in place. This dynamic kept A23a spinning in one place, delaying its expected northward drift.

A23a is expected to continue its journey towards the Southern Ocean following the Antarctic Circumpolar Current, which is likely to propel it towards the subantarctic island of South Georgia. In that region you will find warmer water and it is expected to break up into smaller icebergs and eventually melt.

Andrew Meijers, oceanographer at the British Antarctic Survey (BAS), stated in a statement: It’s exciting to see A23a moving again, after periods of stagnation. We are interested to see if it will take the same route taken by other large icebergs that have broken off from Antarctica. And more importantly, what impact will this have on the local ecosystem?.

Exactly one year ago, researchers aboard the ship RRS Sir David Attenborough They observed and studied the iceberg while on a scientific mission in the Weddell Sea for the Biopole project. Scientists took the first photographs of the moving iceberg while observing how Antarctic ecosystems and sea ice influence global ocean carbon and nutrient cycles.

Laura Taylor, biogeochemist on the Biopole cruise ship, highlighted: Giant icebergs provide nutrients to the waters they pass through, creating thriving ecosystems in otherwise less productive areas. What we do not know is what difference certain icebergs, their scale and their origins can make in this process..