Harbor seals off the coast of Alaska choose the icebergs on which they bask relying on the season, in keeping with new analysis introduced as we speak on the American Geophysical Union’s annual assembly.
The analysis centered on harbor seals in Alaska’s Glacier Bay National Park, the place the Johns Hopkins glacier is advancing—one of many few on Earth doing so, in keeping with an AGU launch. Due to the circumstances of its development, the glacier isn’t shedding many icebergs right into a fjord, lowering the seals’ habitat. The latest analysis investigated the kinds of icebergs the harbor seals (Phoca vitulina) elect to sit back on (no pun meant) over the course of the 12 months.
“Icebergs are discovered all through the fjord in areas of quick circulate, inside eddies, and near the glacier,” mentioned Lynn Kaluzienski, a researcher on the University of Alaska Southeast and lead creator of the research, within the launch. “We needed to know which of those areas seals had been utilizing and the way this habitat is altering in response to advances on the glacier entrance and discount in iceberg numbers.”
The researchers discovered that seals tended to arrange store on slower-moving icebergs through the pupping season (June) and faster-moving bergs throughout molting season (August). The group categorized slower-moving icebergs as these shifting at a tempo of seven to eight inches (0.2 meters) per second. During molting season, the seals tended to be on bergs nearer to fast-moving water made up of ocean currents and glacial runoff, known as the plume. The plume surfaces plankton and fish, in keeping with the AGU launch, providing up a feast for the seals.
The group posits that the slower bergs supply extra stability to grownup seals tending to their pups within the early summer season. During molting season that stability is much less essential, and the sooner bergs supply alternatives to eat with ease.
“Our work gives a direct hyperlink between a glacier’s advance and seals’ distribution and conduct,” Kaluzienski mentioned. “Interdisciplinary research like this one coupled with long-term monitoring campaigns will probably be essential to know how local weather change will affect tidewater glacier fjord ecosystems sooner or later.”
Climate change might drastically change the seals’ environments; an AI-driven evaluation of 10 local weather fashions launched as we speak discovered that 34 areas outlined by the International Panel on Climate Change (IPCC) have a 50/50 probability of warming by 3.6 levels Fahrenheit (2 levels Celsius) in comparison with preindustrial ranges.
It’s been a busy 12 months for seals extra usually. In February, a male elephant seal prompted a stir when it saved a drowning pup, shoving again to shore with its head. Not all of the information was so fantastic: In July, 9 seals off the coast of South Africa examined optimistic for rabies, after months of reviews of seals attacking people.
The seals off Alaska are having a chiller go of it than their South African compatriots. The discount in iceberg numbers isn’t good for them, however no less than they don’t have rabies. There’s at all times a silver lining!
