That’s why a team from the Sea Mammal Research Unit at the University of St Andrews, in Scotland, enlisted the help of some of Antarctica’s permanent residents: seals.
The furry, aquatic mammals thrive year-round in the freezing climate and can dive up to 3,000 feet below the water’s surface says Lars Boehme, an oceanographer and one of the project’s leaders.
By fitting the seals with sensors, the researchers gain insight into the seals habits and ecology, while also gathering data from inaccessible parts of the ocean.
Scientists around the world are now drawing on this data to learn more about the Antarctic environment and how it could impact climate change.
While six seal species live in Antarctica, only Weddell and southern elephant seals dive into the deeper layers of the ocean — the main reason these species were chosen for data collection, says Boehme. The seals are hunted by orcas and other seals in the water, but have no land predators, so the scientists can approach them easily. “They’re not running away,” says Boehme.
The team members sedate the seals with a blow dart and glue a smartphone-sized sensor to the fur on the backs of their heads. The process doesn’t hurt the animals or impact their social lives, says Boehme. Seals molt annually, so the device falls off after a year.
Boehme says the team are careful to minimize their interactions with the seals. Tagging up to 14 seals per trip in 2014, 2019, and 2020, the team have got the process down to just 10 minutes per seal he says, and are working to reduce the size of the devices.
As the seals swim through the ocean, the device collects information about the depth, temperature, and salinity of the water at different locations. When the seals come to the surface for air, the “data profiles” are transmitted via satellite.
When the project started in 2014, Boehme says there was less than 1,000 data profiles available for the Amundsen Sea area. Now, with the help of the seals, the team has more than 20,000 data points from thousands of locations around Antarctica.
In hot water
Yixi Zheng, who is undertaking a PhD in environmental sciences at the University of East Anglia, in the UK, has used data collected by seals in the Amundsen Sea in 2014 to investigate melting at Pine Island Glacier.
Moving from the lower to upper zone of the ocean, this warm meltwater causes the surface water’s temperature to rise, which leads to more sea ice at the surface melting. The meltwater forms relatively warm lagoons, called polynyas.
While melting ice contributes to rising sea levels, the polynyays do have some environmental benefits, says Zheng.
Rich in nutrients and minerals from the land, the meltwater promotes growth of algae, which absorbs CO2 and attracts tiny creatures like krill, that form the basis the ocean food chain.
Zheng says the exact size and numbers of polynyas is difficult to pin down, but that permanent polynyas are forming in front of Pine Island Glacier, where this data was collected.
Using seals to collect data and analyzing it, as Zheng has, can help narrow those predictions, and give scientists a clearer idea of what we’re up against, Boehme tells CNN.
“For me, that’s the exciting bit: when Yixi started to talk about what she found, then we begin to better understand these processes that might impact the melting of these glaciers,” he says.