The worlds largest Iceberg, lovingly named A68a has been steadily drifting towards South Georgia island, A remote British Overseas Territory in the Southern Atlantic Ocean.
The giant berg is almost the same size as South Georgia raising environmental concerns if it grounds itself in the shallow seas surrounding the island.
South Georgia is a haven for penguins and seals such as elephant seals, and it is feared that the extreme size of the iceberg will restrict their access to the sea, forcing them to abandon their offspring.
They would be unable to routinely navigate hundreds of kilometres around the iceberg every time they needed to feed leading ecologists to fear for a decline in birth rate on the island.
“A close-in iceberg has massive implications for where land-based predators might be able to forage,” explained Prof Tarling.
“When you’re talking about penguins and seals during the period that’s really crucial to them – during pup- and chick-rearing – the actual distance they have to travel to find food (fish and krill) really matters. If they have to do a big detour, it means they’re not going to get back to their young in time to prevent them starving to death in the interim.”
When another colossal berg A38 grounded on South Georgia in 2004 massive numbers of dead seal and penguin chicks were found along the beaches.
Creatures living on the seafloor endure a worse fate: being crushed under the 200 metre thick ice giant as it grinds its way to a slow halt in the seabed.
However this would extend to the islands economy as well, Toothfish, Icefish and Krill are all important species to the fishing industry here.
The iceberg is so large it would restrict fishing in the area both physically in terms of navigation, and because of the destruction wreaked on the local ecosystem.
Toothfish, Icefish and Krill are all important species to the fishing industry her
“Ecosystems can and will bounce back of course, but there’s a danger here that if this iceberg gets stuck, it could be there for 10 years,” said Prof Geraint Tarling from the British Antarctic Survey (BAS).
Large icebergs often end up beached around South Georgia due to oceanic currents pushing bergs calving off of the Larcen C ice sheet north alongside the Antarctic peninsula.
The shallow waters around South Georgia means that it has a large catchment area for icebergs, increasing the chances for A68a to become stuck here.
However if the iceberg does end up beached at South Georgia, the impacts won’t all be negative.
Icebergs release a huge amount of dust that will help to fertilise ocean plankton, a benefit that will cascade up the food chain.
Although A68a is projected to intercept South Georgia it might miss it altogether according to Dr Peter Fretwell, a remote-sensing and mapping specialist for the British Antarctic Survey.
“The currents should take it on what looks like a strange loop around the south end of South Georgia, before then spinning it along the edge of the continental shelf and back off to the northwest. But it’s very difficult to say precisely what will happen,” he said.
Fretwell’s colleague Dr Andrew Fleming said a request had been made of the European Space Agency for more detailed iamgery.
It’s Sentinel-1 radar spacecraft is capable of penetrating cloud layers, allowing tracking of A68a in all weather conditions.
“A68a is spectacular,” says Fleming. “The idea that it is still in one large piece is actually remarkable, particularly given the huge fractures you see running through it in the radar imagery. I’d fully expected it to have broken apart by now.
“If it spins around South Georgia and heads on northwards, it should start breaking up. It will very quickly get into warmer waters, and wave action especially will start killing it off.”