Heavy sea ice conditions have thwarted a science mission from reaching the Larsen C Ice Shelf in Antarctica from which a large iceberg broke off in July 2017. A team of scientists, led by the British Antarctic Survey (BAS), are on board the RRS James Clark Ross.  Sea ice, up to 4-5 metres thick, made progress for the ship very slow and the ship’s captain made the difficult decision not to continue.

The team was on the way to investigate a newly exposed marine ecosystem after a huge iceberg calved off in July 2017. They are now heading north to areas which have never been sampled for benthic biodiversity.

Emperor Penguins on the sea ice in front of RRS James Clark Ross. (Picture: BAS)
Emperor Penguins on the sea ice in front of RRS James Clark Ross. (Picture: BAS)

In July 2017 a massive iceberg calved off from the Larsen Ice Shelf. The iceberg which is known as A68 has four times the size of London. After it broke off it exposed an area of around 5,818 km2 of seabed. The ecosystem beneath the ice has most likely been hidden for thousands of years.  As sunlight enters the water the undersea environment will change dramatically, and new species will begin to colonise the ocean floor.

As iceberg A68 moves north, it will leave an area of 5,800 km2 of seabed that was hidden beneath the ice shelf for up to 120,000 years, newly exposed to open marine conditions. (Picture: Pierre Markuse)
As iceberg A68 moves north, it will leave an area of 5,800 km2 of seabed that was hidden beneath the ice shelf for up to 120,000 years, newly exposed to open marine conditions. (Picture: Pierre Markuse)

The scientists planned to collect samples from this newly exposed seabed. But now thick sea-ice of up to 4-5 meters thick has thwarted the scientists from reaching their destination. Marine biologist and Principal Investigator, Dr Katrin Linse, from British Antarctic Survey is leading the team.  She says: “We knew that getting through the sea ice to reach Larsen C would be difficult. Naturally, we are disappointed not to get there but safety must come first. The captain and crew have been fantastic and pulled out all the stops to get us to the ice shelf, but our progress became too slow, with just 8 km travelled in 24 hours and we still had over 400 km to travel. Mother Nature has not been kind to us on our mission!” “But we have a ‘Plan B’, we will head north to areas which have never been sampled for benthic biodiversity. The Prince Gustav Channel Ice Shelf and neighbouring Larsen A Ice Shelf collapsed in 1995. We’ll be sampling deeper than we planned at Larsen C – down to 1000 metres – so we’re excited about what deep sea creatures we might find.”

Researchers were headed to iceberg A68, which split off from the Larsen C ice shelf in July 2017. But some 400 kilometres from their destination, ice forced the researchers to change course. They are now heading through relatively ice-free waters to the Larsen A ice shelf, where a giant iceberg broke off in 1995. No biological expedition has examined the seafloor since the break, said marine biologist Katrin Linse. “We’re excited about what deep-sea creatures we might find.” (Picture: BAS)
Researchers were headed to iceberg A68, which split off from the Larsen C ice shelf in July 2017. But some 400 kilometres from their destination, ice forced the researchers to change course. They are now heading through relatively ice-free waters to the Larsen A ice shelf, where a giant iceberg broke off in 1995. No biological expedition has examined the seafloor since the break, said marine biologist Katrin Linse. “We’re excited about what deep-sea creatures we might find.” (Picture: BAS)

The international team, from nine research institutes, left Stanley in the Falkland Islands mid-February to spend 3 weeks on board the BAS research ship RRS James Clark Ross. They will now use the remainder of the expedition to collect seafloor animals, microbes, plankton, sediments and water samples using a range of equipment, including video cameras and a special sledge pulled along the seafloor to collect tiny animals. Their findings will provide a benchmark of the seafloor biodiversity in this area and provide a more accurate timeframe for the retreat of ice sheets from the eastern side of the Antarctic Peninsula.

Marine biologist Dr Katrin Linse from British Antarctic Survey is leading the mission. She says:
Marine biologist Dr Katrin Linse from British Antarctic Survey is leading the mission. She says: "We've put together a team with a wide range of scientific skills so that we can collect as much information as possible in a short time. It's very exciting." (Photo: BAS)

While the team is on the expedition, glaciologists and remote sensing specialists continue to monitor the movement of the Larsen C Ice Shelf. In December 2017, a team from University of Leeds worked on the remaining ice shelf to investigate changes in ice structure after the calving event, to be able to predict shelf stability in the future. In 2019 Dr Katrin Linse and colleagues are planning more missions to access the Larsen C ice shelf. They have teamed up with the Alfred Wegener Institute in Germany to visit on their research vessel the RV Polarstern.

Examples of deep sea animals previously collected by BAS in the Weddell Sea (Picture: BAS)
Examples of deep sea animals previously collected by BAS in the Weddell Sea (Picture: BAS)

Source: British Antarctic Survey / ScienceDaily / Senckenberg Research Institute and Natural History Museum