Recently, scientists noticed an impressive event taking place in the largest iceberg in the world, the A23a. For months it was detached and spinning in Antarctica, when in fact it should have been working alongside Earth’s strongest ocean current.
According to BBC reportscientists say the frozen mass, which is more than twice the size of Greater London, was trapped at the top of a giant spinning water cylinder.
The Iceberg Path – How It Got Caught
Oceanographers call this phenomenon a Taylor plume – and it’s possible that A23a won’t escape its captor for years. “We usually think of icebergs as transient things – they break up and melt. But not this one,” observed polar expert Professor Mark Brandon. The Open University researcher added that “A23a is the iceberg that just refuses to die.”
Its longevity is well documented. It was released from the Antarctic coast in 1986, but almost immediately got stuck in the mud of the Weddell Sea. For three decades it was a stationary “ice island”. He didn’t move. It wasn’t until 2020 that it started to float and drift again, slowly at first, before eventually shooting north to warmer regions.
The map shows how the iceberg stopped
The iceberg remains in place
In early April, A23a entered the Antarctic Current (ACC) – the largest and most powerful ocean current on Earth – which moves a hundred times more water around the world than all of Earth’s rivers combined. This would have the effect of pushing the nearly trillion ton iceberg and launching it into the South Atlantic. In contrast, A23a was not moved.
It remains in place just north of the Orkney Islands, making a counter-clockwise rotation of about 15 degrees per day. And that will result in the deterioration and eventually its disappearance will be delayed. A23a is not re-grounded. there are at least a thousand meters of water between its bottom and the seabed.
“The ocean is full of surprises and this dynamic feature is one of the most beautiful you’ll ever see,” said Professor Mike Meredith of the British Antarctic Survey. “Taylor columns can also form in the air; you see them in the movement of clouds over mountains,” he added.
The map shows how the iceberg broke up
How long can the iceberg spin?
A23a is a perfect illustration again of the importance of understanding the shape of the seabed. Seamounts, canyons and slopes have a profound effect on the direction and mixing of waters and the distribution of nutrients that drive biological activity in the ocean.
And this influence also extends to the climate system: it is the mass movement of water that helps spread heat energy around the world. The behavior of A23a can be explained because the ocean floor just north of South Orkney is fairly well studied. This is not the case for much of the rest of the world.
Currently, only a quarter of the Earth’s sea floor has been mapped according to the best modern standards.