A new study finds that melting water from Antarctic glaciers is changing the composition of the region’s oceans more than was previously known. The measures that made these findings possible were collected by an unusual group of researchers: seals.
The study, published Friday in Communications: Earth and Environment, uses measurements of water temperature and salinity to show how glacial melting water changes the composition of the ocean near the Pine Island Glacier. one of the most retreating glaciers on the continent. The researchers found that fresh, warm melting water was distributed in patches all over the ocean, including portions that rose near the surface. These surface layers bring iron and other nutrients to the top of the ocean, encouraging the growth of algae and other biomass and keeping the ocean relatively free of ice.
“In this part of the sea, glaciers are melting so fast that they are called ‘Doomsday Glaciers“,” Said Yixi Zheng, lead author of the study and a graduate researcher at the University of East Anglia. “We are really worried about what is happening in this region. We want to know how quickly they melt and the impact of these glaciers on the climate system.
Although glacial thaw water is best measured in winter, when its hydrographic signature is clearer, this has always been a problem for scientists. The Pine Island Glacier is not only extremely remote, but the ocean near the glacier is covered in ice ten months a year, making access to deeper parts of the ocean with human instruments almost impossible. to obtain.
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However, seals can swim under sea ice. Zheng and his team used a data set collected by seals swimming near the Pine Island Glacier and equipped with sensors that collected water temperature, salinity and pressure. The seals were then inspected between July and September 2014.
“Seals, they’re so amazing,” Zheng said. “They are very good at finding small holes in the sea ice. Sometimes, I feel like we should doctor them. They are doing better than many scientists. “
As versatile as seals are, they are not perfect researchers. You can’t control where a seal will swim, so you can’t ask them to patrol a specific area. This makes them somewhat erratic collaborators, but the team was lucky with the ones they had.
“It simply came to our notice then. Right in front of the glacier, we had this seal hanging, having a winter vacation, ”said Zheng. No wonder a seal chooses to settle near a melting glacier: as Zheng’s study shows, thawing water on the surface of the ocean near glaciers encourages algae, which means more food for seals.
Researchers have also used seals in other studies. Some of the most charismatic mammals in Antarctica also helped solve what caused a massive hole to form in the sea ice of the region. Scientists have done the same stamps controlled from space as an indicator of the health of various Antarctic ecosystems. These ecosystems support the crucial fisheries on which humans rely, and what happens to the continent’s massive ice masses has implications for coastal populations around the world. In a region that is changing rapidly, any additional information that researchers can gather so that they can understand what is happening is vital to planning what comes next.
Zheng, who tagged seals on a trip to Antarctica in 2019, said he sees many opportunities for seals to help scientists collect measurements and believes stamp label data will be more popular in future studies. Sensors equipped with seals, Zheng said, cost between about $ 4,000 and nearly $ 7,000. It 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 love the data on the label labels and we try to make the most of them,” Zheng said.