In July 2017, a giant iceberg broke off from the Larsen C ice shelf east of the Antarctic Peninsula, unveiling a large swathe of ocean that has existed in darkness beneath the ice for more than 100,000 years, and might hold clues to the evolution and mobility of marine life and its response to climate change –an unexplored world that has existed longer than the evolution of the human neocortex, our “super-brain,” no later than 75,000 years ago that spurred our capacity for novelty and invention.
A team led by Boris Dorschel, with the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), chief scientist of a 45-strong international team on board the German research icebreaker Polarstern, is embarking from Chile this week to explore for the first time the part of Antarctica uncovered by the world’s biggest iceberg, A-68. The ship is currently docked in Puntas Arena in Chile, where it is being loaded for the nine-week expedition.
If the team succeeds, it could catalog a bounty of novel specimens, says Huw Griffiths from the British Antarctic Survey (BAS). “We’ve been studying Antarctica for a long time now, but even in areas we think we know pretty well – about 10% of what I find at the bottom of the sea is new to science. So, I’m expecting that in an area that no-one’s ever been to before – for that number to be much higher, and for there to be a wider variety of new species,” he told BBC News.
The 5,800 sq km frozen slab broke away from the continent in 2017, reports the BBC, exposing ocean floor that had been covered for at least 120,000 years. A Delaware-sized iceberg, shown below, calved when a crack in the Larsen C ice shelf reached the Weddell Sea. In this satellite image from September, rifts are visible in the ice and clouds cast a shadow on the new iceberg.
The researchers will need luck on their side, however. The region they are targeting in the Weddell Sea is notorious for thick sea-ice. “It’s thrilling to explore one of the last white spots on Earth,” says Dorschel, who is based at the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany. “But it’s a nerve-racking affair, too. Local weather and ice conditions might interfere any time.”
“These ice shelves are all around Antarctica, and this is our chance to get in there and study where a large segment of Larsen once was – before its sea-floor changes. It’s a wonderful opportunity to understand how the marine biology works around the continent,” said Griffiths.
Scientists are keen to explore what species might have thrived under the ice, and how the ecosystem has coped with the sudden change, observes Nature. The first attempt to do so failed last year, when sea ice up to 5 meters thick forced the James Clark Ross vessel, operated by the British Antarctic Survey (BAS), to turn back in February 2018.
In January, a team on board the South African research vessel Agulhas II anchored at a site 200 kilometers north of where the iceberg broke off. It took ocean and sea-floor samples there, but sea-ice conditions and other research priorities meant it didn’t go further south. The Polarstern will now attempt to advance farther south, to the site where the iceberg calved.
The Polarstern, operated by the Alfred Wegener Institute, is Germany’s flagship polar explorer vessel and one of the best-equipped research icebreakers in the world. Satellite imagery and renaissance flights by its two helicopters will guide the ship through the pack ice — ice floating in the sea, formed by smaller pieces freezing together — which can be abundant even in southern summer months, when the extent of sea ice is close to its annual minimum.
If ice and weather conditions allow, the team could reach the site from Chile within just a few days. The scientists would then have several weeks of southern summer to extensively sample ocean fauna and chemistry, and to map the uncharted seabed.
“We’ll work around the clock to collect as much data as possible,” says Borschel. “We’ve tools on board which should provide a perfect view of the ocean and the sea floor.”
Samples collected in the pristine area, completely unaffected by commercial fishing or other human activities, would be an invaluable resource for biodiversity researchers. The data could help scientists to address questions relating to how marine communities develop, and how quickly new species colonize previously ice-covered areas, says Linse.
Rapidly rising temperatures in the air and ocean around the Antarctic peninsula, a hotspot of global climate change, reports Nature, add urgency to such research: any changes in species composition and food-web structure following the disappearance of ice might shed light on the fate of polar ecosystems in a warming world.
“Here’s a unique opportunity to find out how vulnerable or resilient marine life is to rapid environmental change,” Katrin Linse, a marine biologist at the British Antarctic Survey (BAS). “This is exciting science for us all — I hope very much that it can be done.”