During the low ice age, some polar bears are turning to glacial ice
Holes in sea ice provide the perfect hunting ground for polar bears looking for their main food source, seals.So when the temperature rises sea ice melting, the survival of polar bears is threatened, making them the poster species for many climate change reports and documentaries.Although every polar bear population is threaten Due to the disappearance of this sea ice, some people have developed the ability to adapt to the low ice season.In southeastern Greenland, researchers Found A unique subpopulation of polar bears that hunted to find a way to live in areas with low sea ice icy mixture– A mixture of floating icebergs formed by the disintegration of glaciers, sea ice and snow that forms at the base of glaciers, surviving the warmer seasons.
The findings were published in the journal in June science An international team of Arctic scientists. The population is genetically isolated from other polar bear groups and survives in fjords that are free of sea ice for more than two-thirds of the year.
A typical image of a polar bear on melting sea ice in the Arctic. Most polar bears rely on sea ice for hunting, and climate change is threatening this important habitat. Photo: Gary Beinbridge/Frick
The Arctic Ocean is a mixture of liquid and frozen seawater in the Arctic. The area and its surrounding adjacent waters provide polar bears with a critical, shrinking habitat. Polar bears use sea ice to travel long distances in search of ringed seals, their preferred prey or other seals and marine mammals. Typically, polar bears wait in holes in the sea ice for their prey to surface for air in order to snatch prey out of the water.
While sea ice in the Arctic Ocean used to regain mass lost in summer during cold, dark winters, it has been steadily declining for decades.it loses on average 27,000 square miles of ice per year Since 1979. That’s bad news for species that depend on sea ice, such as polar bears, which are now forced to spend more time on land and fast for longer. As sea ice breaks up and recedes earlier in the summer, many polar bears have little or no access to food during the warmer months, affecting their physical and reproductive health.
An isolated polar bear population off the southeastern coast of Greenland replenished the low ice age by relying on glacial ice for hunting as sea ice disappeared, according to the new study. Unlike sea ice, where glaciers form on land, sea ice forms and melts in the ocean.Glacier mix is a floating mixture Glaciers, snow and freshwater ice form at the base of glaciers that terminate in lakes and rivers in fjords – narrow valleys formed by ancient ice movements. Since glaciers do not fully melt during the summer, they provide a hunting ground for this subgroup when sea ice is unavailable.
A fjord in Greenland with a mixture of former glaciers. A recent study found that a subpopulation of polar bears in southeastern Greenland hunted on glacial ice rather than sea ice. Photo: NASA Marshall Space Flight Center/Frick
Lead author Kristin Laidre, an associate professor in the University of Washington’s School of Aquatic and Fisheries Sciences, was conducting a decade-long survey of polar bears on Greenland’s east coast with her team when they realized they might be studying two subpopulation, not one. “When we made this completely unexpected discovery, we were assessing what we thought was a subpopulation along Greenland’s 1,800-mile-long east coast,” Ledley said in an interview with GlacierHub. The decade-long survey tracked the movements, genetics and demographics of polar bears on Greenland’s east coast. They also surveyed indigenous subsistence hunters in eastern Greenland and incorporated their traditional ecological knowledge into the study.
Using genetic and behavioral data, Laidre and her team realized they had discovered a new subpopulation of polar bears off the southeastern coast of Greenland — “the most genetically isolated polar bear in the world,” according to Laidre. In other words, while these bears remain the same species as other polar bears, they are genetically and demographically distinct from other subpopulations. Genetic diversity is important to species because it allows them to adapt to changing environments. While more research on the population is needed, a combination of genetic diversity and behavioral adaptations allow these bears to hunt on glacial ice to supplement their diets during low sea ice seasons.
Laidre stressed that the study does not mean that bears are not threatened by sea ice loss. “Glacier ice can help a small number of polar bears survive longer in a warmer climate, but the vast majority cannot access it,” she explained.In the long run, she points to the importance of studying this population and other polar bears to understand where polar bears may be living and how genetic diversity can help other species threatened by climate change.
