In what probably made a cracking sound loud enough to be heard for miles, the massive, Rhode Island-sized iceberg threatening iconic wildlife on South Georgia Island in the Atlantic Ocean suddenly broke up into smaller bits sometime between Monday and Tuesday. The iceberg that had appeared in satellite images as a pointed finger has now lost the finger, which has gone rogue.
The National Ice Center has designated the smaller pieces, which are still large in their own right, as A68e and A68f, since they broke off from A68a. According to Laura Gerrish of the British Antarctic Survey, A68f has an area of about 86 square miles, while A68e is larger, at about 253 square miles, which is about 12 times the size of Manhattan.
These tabular icebergs, characterized by steep cliffs along their sides and a flat, plateau-like top, are swirling around in the currents south-southeast of South Georgia Island, a British territory that is home to millions of king and macaroni penguins, seals, sea birds and blue whales that feed on fish and krill just off the coast. Scientists fear that ocean currents and winds could cause the icebergs to retrograde, or move back toward the island, becoming stuck in the shallows along the island’s eastern coast during the coming weeks.
The fissures in this iceberg mark one of the iceberg’s biggest breakup events since moving off the Larsen C Ice Shelf in the Antarctic Peninsula. Typically, tabular icebergs like this one break up by shedding large pieces while moving away from Antarctica, through the Southern Ocean. A new study published in Science Advances found that these icebergs are responsible for injecting huge amounts of cold freshwater into the Southern Ocean, which can have implications for global ocean circulation.
In an effort to study how these massive icebergs disintegrate over time and the effects such breakup events have on the ocean, scientists from the United Kingdom are planning to travel to A68a, wherever it is then located, to observe it in the field. Their field study, slated to begin in mid- to late January, will include the use of underwater drones, among other methods to study this slowly disintegrating, but still massive, slab of ice while it’s either still at sea or stuck on the shallow shelf of South Georgia Island.
Ocean currents moving water around Antarctica are likely to take the main iceberg, A68a, together with its fragment companions around the island and spit them out to the north. From there, they could skirt the shallow areas near the island where they may become stuck.
The main iceberg has lost quite a bit of area since it first broke off the ice shelf. Back then it measured about 2,200 square miles in area and weighed a trillion tons, making it one of the largest icebergs ever observed to break off the Antarctic Ice Sheet. Now, it’s down to a slimmer, though still imposing, size; about 1,004 square miles.
Satellites, like the European Space Agency’s Sentinel series, are providing researchers with an unusually close-up view of this iceberg in near real-time.