Mega 1,000,000,000,000 tonne iceberg drifting in the ocean after breaking away

An iceberg twice the size of Greater London and weighing more than a trillion tonnes is making a bid for freedom.

The ‘megaberg’, named A23a,has begun ‘spinning’ for the first time in almost 30 years after becoming stuck in a vortex off Antarctica.

The huge iceberg, which is 3,800 square kilometres, broke free of Antarctica in 1986 but, because of its size, became lodged on the floor of the Weddell Sea in the Southern Ocean.

A23a first began slowly moving south in 2020 but became trapped in what’s called a Taylor Column in spring of this year.

A Taylor Column is a phenomenon where rotating water above a seamount traps an object in its place.

But after months of spinning, satellite footage has confirmed that the giant iceberg has finally released from the swirling waters.

Doctor Andrew Meijers, an oceanographer at the BAS, commented: ‘It’s exciting to see A23a on the move again after periods of being stuck.

‘We are interested to see if it will take the same route the other large icebergs that have calved off Antarctica have taken.’

BAS experts now expect the mega iceberg to continue its drift into the Southern Ocean where it will eventually reach the Atlantic.

Once it reaches the Atlantic, A23a is expected to melt due to increased temperatures.

The South Atlantic Ocean, off the coast of South America, is usually around 5°C, which is considerably warmer than the Southern Ocean.

The ‘megaberg’ is being studied by researchers aboard the RRS David Attenborough, a 125-metre long research vessel built in 2024.

Laura Taylor, a biochemist aboard the ship which is currently off the coast of the Falkland Islands, said: ‘We know that these giant icebergs can provide nutrients to the waters they pass through, creating thriving ecosystems in otherwise less productive areas.

‘What we don’t know is what difference particular icebergs, their scale, and their origins can make to that process.

‘We took samples of ocean surface waters behind, immediately adjacent to, and ahead of the iceberg’s route.

‘They should help us determine what life could form around A23a and how it impacts carbon in the ocean and its balance with the atmosphere.’

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