The giant berg a 68 looks finally to be on the move

The giant berg a 68 looks finally to be on the move

Recent weeks have seen it shuffle back and forth next to the Antarctic ice shelf from which it broke away. But the latest satellite imagery now indicates the near-6,000 sq km block is swinging out into the Weddell Sea.

Polar experts expect the trillion-tonne block to essentially bump along the shelf edge until it reaches the great eastward movement of ocean water known as the Antarctic Circumpolar Current. This would then export what is one of the largest bergs ever recorded out into the South Atlantic.

How far A-68 actually gets along this predicted path is anyone's guess, however. The berg already shows evidence of fragmentation at its edges.A-68 calved during mid-winter and it required radar satellites - such as Europe's Sentinel-1 spacecraft - with their unique ability to pierce cloud and darkness to keep track of developments.

With the return now to longer days in the Antarctic, opportunities are increasingly opening up for high-resolution optical satellites to take a close look at the state of the berg.And new imagery from the Spanish Deimos-2 spacecraft shows how the initial sharp edges of the block's northern-western corner have been lost.Scientists are not just looking at the berg; they also continue to monitor the Larsen Ice Shelf. They are checking to see if its behaviour has changed since the calving.

The shelf is the floating protrusion of glaciers coming off the Antarctic landmass, and the ejection of such a large section of its structure could potentially trigger further fracturing or a change in the speed of ice flow.So far, however, there is little evidence of either.

When A-68 moves clear of its birth position it will reveal seafloor that probably has not been free of ice cover for 120,000 years - during the peak of the last warm phase in Earth's history known as the Eemian. The area has already gained protected status from the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR).This gives scientists priority access and keeps fisheries activity at bay for a minimum of two years.Previous research in locations uncovered by departing bergs has found new species.

EXTRA INFO.
What is an iceberg?
Icebergs are pieces of ice that formed on land and float in an ocean or lake. The term "iceberg" refers to chunks of ice larger than 5 meters (16 feet) across. Smaller icebergs, known as bergy bits and growlers, can be especially dangerous for ships because they are harder to spot. The North Atlantic and the cold waters surrounding Antarctica are home to most of the icebergs on Earth.

Why are icebergs important?
Icebergs pose a danger to ships traversing the North Atlantic and the waters around Antarctica. After the Titanic sank near Newfoundland in 1912, the United States and twelve other countries formed the International Ice Patrol to warn ships of icebergs in the North Atlantic.
Icebergs can also serve as tools for scientists, who study them to learn more about climate and ocean processes.

Why do scientists study icebergs?
Climate scientists study icebergs as they break up for clues to the processes that cause ice shelf collapse. Scientists have noticed that the way icebergs break up when they reach warmer waters mirrors the disintegration of Antarctic ice shelves. By studying the factors that cause icebergs to break up, researchers hope to better understand the influences that lead to ice shelf breakup, and to better predict how ice shelves will respond to a warming climate.

Oceanographers follow icebergs because the cold freshwater they contribute to the sea can influence currents and ocean circulation far away from their origins.

Biologists study icebergs to find out how they influence ocean life. As icebergs melt, they leak nutrients into the ocean around them. Recent studies have shown that the water surrounding icebergs teems with plankton, fish, and other sea life.