The iceberg that broke away from the Larsen C ice shelf last summer opened up access to an ecosystem that hadn’t seen the light of day in up to 120,000 years. There’s a small window of time for scientists to examine that ecosystem before sunlight and new water change it.
That’s why British Antarctic Survey scientists are headed into the breach left behind by the Larsen C iceberg next week. They’ll gather samples, photos and reams of data in an effort to understand what an ancient, largely undisturbed ecosystem looks like. The data they collect will also be a baseline to study change in the region in the coming years.
While large icebergs have broken away from Antarctica before, this is the first time scientists have been able to rapidly assess newly-exposed waters. Two other ice shelves on the Antarctic Peninsula, Larsen A and B, disintegrated in 1995 and 2002 respectively, but it took years to get permits and research cruises scheduled to visit the newly opened water. By the time scientists got there, the old ecosystems had been altered and new plants and animals had moved into the area.
Scientists have also used drilling and other techniques to look at ancient ecosystems under other ice shelves, but those methods often leave an incomplete picture.
“Cameras have recorded seafloor animals up to 150 km away from the open sea on Amery ice shelf but only photos of tiny area were taken through drill hole,” Katrin Linse, senior biodiversity biologist with the British Antarctic Survey, told Earther. “No specimens collected that could be fully identified and studied.”
The trip to the open water around Larsen C will change all that. Assuming scientists can navigate the sea ice that’s growing as summer wanes in Antarctica, they’ll have unprecedented access to the entire water column.
Linse said she’s expecting to find species smaller than the tip of a pencil, with most animals smaller than three centimeters (one inch). What all of them will have in common is the ability to live without light. That could include some bizarre adaptations, including “sponges that are sticky and catch prey instead of filtering water; small bivalves/clams having changed to suck in tiny shrimps instead of filtering; polychaete worms feeding on others and detritus-eating sea cucumbers.”
In addition to gaining an intimate understanding of life formerly under the ice, the data will serve as a baseline to see how the area changes as sunlight and open water alters the chemistry and new species migrate in. That has huge implications for predicting the fate of ecosystems under the rest of the continent’s ice shelves.
While most scientists believe Larsen C’s breakdown was largely natural, climate change is creating unstable conditions across Antarctica. Ice shelves in West Antarctica, in particular, face a potentially rapid retreat driven by warm water intruding and eating away at ice from below. Even East Antarctica, long thought to be insulated from climate change, is showing some worrying signs. The data collected in Larsen C’s breach could provide insights into how future exposed ecosystems will fare.
This cruise wouldn’t be happening if climate change wasn’t a major concern. The Commission for the Conservation of Antarctic Marine Living Resources governs much of the research and conservation measures going on around the seventh continent. Scientists have become growingly concerned about ice shelf collapse, and in 2016, they proposed a new rule allowing for special study areas following collapse or massive calving events.
The rule was adopted, and now appears prescient. The area around Larsen C is the first to be designated a special study area, and the British Antarctic Survey will be the first research cruise to explore it. Chances are it won’t be the last, though.