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Delaware-Sized Iceberg Could Decimate Wildlife on South Atlantic Island

Iceberg A68a is on track to hit the British Territory of South Georgia, where it could complicate access to food for millions of seals and seabirds

A satellite image shows the A68a iceberg in the lower left. The chunk of ice looks a bit like a pointed finger, and scientists say it's currently on a path to collide with the British Overseas Territory of South Georgia. (Copernicus Sentinel 3 Mosaic / Polar View)
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A hulking block of ice adrift in the frigid South Atlantic is on a collision course with the island of South Georgia, a British Overseas Territory, and a direct hit could have disastrous implications for local wildlife, reports Jonathan Amos for BBC News.

The iceberg, known as A68a, cut loose from Antarctica’s Larsen C Ice shelf in July 2017, reports Kara Fox of CNN. At 1,815 square miles, A68a is slightly larger than South Georgia itself and weighs “hundreds of billions of tons” per BBC News.

“It is absolutely huge and it’s the largest iceberg around in the Southern Ocean,” Sue Cook, a glaciologist at the Australian Antarctic Program Partnership, tells Graham Readfearn of the Guardian.

After drifting around 870 miles north through “iceberg alley,” A68a is presently about 300 miles southwest of the island, which hosts large populations of seals, penguins and albatross. Though the berg’s final path remains hard to predict, if the iceberg runs aground and becomes stuck just off South Georgia’s shores it would have “massive implications” for the island’s abundant wildlife, says Geraint Tarling, an ecologist with the British Antarctic Survey (BAS), in a statement.

“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 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,” says Tarling. He adds that the ecosystems would eventually recover, but that the iceberg could park itself in front of South Georgia for up to a decade, which would “make a very big difference, not just to the ecosystem of South Georgia, but its economy as well.”

Killer whales off the coast of South Georgia Island
Whales, seals and penguins depend on easy access to the waters off the coast of South Georgia, which could be significantly complicated by an iceberg as large as A68a. (Martin Collins)

If the iceberg does approach South Georgia, it will also grind along a swath of the seabed, pulverizing any marine life populating the ocean floor. The collision would also kill off photosynthetic algae by blocking sunlight and flood the immediate vicinity with fresh water, per CNN. These events could impact the region’s fish populations which support nearby fishing economies and the many whales that frequent the area to forage.

Interestingly, the iceberg hasn’t been all doom and gloom for wildlife. “The iceberg does bring benefits if it remains in the open ocean, says Tarling in the statement. “It carries enormous quantities of dust that fertilize the ocean plankton in the water that cascades up the food chain. This plankton also draws in carbon from the atmosphere, partially offsetting human CO2 emissions.”

At its current speed of roughly 0.6 miles per hour, A68a could arrive at South Georgia’s doorstep in three to four weeks, but that’s if it floats in a straight line, which Tarling tells CNN is unlikely. "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,” Peter Fretwell, a remote-sensing and mapping specialist with the BAS, tells BBC News. “But it's very difficult to say precisely what will happen."

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