A new study finds that melting waters in Antarctic glaciers are changing the structure of the region’s oceans more than previously known. The measurements that made these discoveries possible were collected by an unusual group of researchers: seals.
The study, published Friday in Communications: Earth and the Environment, uses measurements of water temperature and salinity to show how melting glacial water changes the structure of the ocean near the Pine Island Glacier. one of the most rapidly retreating glaciers on the continent. The researchers found that warmer, fresher meltwater was distributed in patches across the ocean, including portions rising near the surface. These surface layers bring iron and other nutrients to the top of the ocean, encouraging algae and other biomass to grow, as well as keeping the ocean relatively ice-free.
“In this part of the sea, glaciers are melting so fast that I call them”Doomsday Glaciers“Said Yixi Zheng, lead author of the study and a postgraduate researcher at the University of East Anglia. “We really care about what’s going on in that region. We want to know how fast the impact of these glaciers on the climate system is melting ”.
While glacial meltwater is best measured in winter, when its hydrographic signature is clearest, it has always posed a problem for scientists. Pine Island Glacier is not only extremely remote, but the ocean near the glacier is covered in ice for 10 months of the year, making access to deeper parts of the ocean with human instruments almost impossible to obtain.
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However, seals can swim and swim under sea ice. Zheng and her team used a data set collected by seals swimming near the Pine Island Glacier, which were equipped with sensors that collected water temperature, salinity and pressure. The seals were then monitored between July and September 2014.
“The seals are so amazing,” Zheng said. “They are very good at finding small holes in the sea ice. Sometimes I feel like we should give them a doctorate. He does better than many scientists. “
As versatile as seals may be, they are not perfect researchers. You can’t control where a seal will swim, so you can’t ask it to patrol a certain area. This makes them somewhat irregular collaborators, but the team was lucky with the ones they had.
“It simply came to our notice then. Right in front of the glacier, I had this seal hanging, having a winter vacation, ”Zheng said. Not surprisingly, a seal would choose to set up shop near a melting glacier: As Zheng’s study shows, melted water on the ocean surface near glaciers encourages algae, which means more food for seals.
Researchers have used seals in other studies. Some of the most charismatic mammals in Antarctica have also helped solve what caused a massive hole to form in the sea ice of the region. Scientists also have monitored seals in space as a proxy for how healthy the various Antarctic ecosystems are. These ecosystems support the crucial fisheries on which humans rely, and what happens to the continent’s massive ice deposits has implications for coastal populations around the world. In a region that is changing rapidly, any additional data that researchers can gather so that they can cope with what is happening, is vital to planning what follows.
Zheng, who labeled the seals herself on a trip to Antarctica in 2019, said she sees many opportunities for seals to help scientists collect measurements and believes seal label data will become more popular in future studies. Sensors equipped with seals, Zheng said, cost between about $ 4,000 to about $ 7,000. This may seem expensive, but it is astronomically cheaper than sending a team of scientists with expensive equipment to camp in Antarctica to collect similar data.
“We really like the seal label data and try to make the most of it,” Zheng said.