Ice in Bering Sea Declines to Lowest Level in 5,500 Years

 Ice breaks up early on the Kuskokwim River beside the Bering
Sea and near the climate change-affected Yupik Eskimo village of
Quinhagak on the Yukon Delta in Alaska, April 12, 2019. (AFP Photo)
Ice breaks up early on the Kuskokwim River beside the Bering Sea and near the climate change-affected Yupik Eskimo village of Quinhagak on the Yukon Delta in Alaska, April 12, 2019. (AFP Photo)
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Ice in Bering Sea Declines to Lowest Level in 5,500 Years

 Ice breaks up early on the Kuskokwim River beside the Bering
Sea and near the climate change-affected Yupik Eskimo village of
Quinhagak on the Yukon Delta in Alaska, April 12, 2019. (AFP Photo)
Ice breaks up early on the Kuskokwim River beside the Bering Sea and near the climate change-affected Yupik Eskimo village of Quinhagak on the Yukon Delta in Alaska, April 12, 2019. (AFP Photo)

Winter ice in the Bering Sea, in the northern Pacific Ocean between Alaska and Russia, is at its lowest level in the past 5,500 years.

Researchers analyzed vegetation that accumulated on the uninhabited island of Saint Matthew over the last five millennia.

According to AFP, they looked at variations in peat layers of oxygen atoms called isotopes 16 and 18, whose proportions over time correlate with atmospheric and oceanic changes and precipitation.

The 1.45-meter peat core, taken from Saint Matthew in 2012, represented 5,500 years of accumulation.

"It's a small island in the middle of the Bering Sea, and it's essentially been recording what's happening in the ocean and atmosphere around it," said Miriam Jones, the researcher who conducted the study at the University of Alaska and then at the US Geological Survey.

The ice in the Arctic and Bering Seas melts in summer and freezes anew in winter, but satellite observations only date back to 1979. The advantage of the new analysis, published in the journal Science Advances, is that it goes back much further in time.

For the Arctic, the reduction of winter ice in recent decades is clear and rapid, in parallel with global warming and the increasing concentration of carbon dioxide in the atmosphere. But the Bering Sea in recent decades has seemed stable, the authors of the study say, with the exception of 2018 and 2019, when a strong reduction was observed. In this study, researchers tried to establish whether the current levels are an anomaly or a trend.

"What we've seen most recently is unprecedented in the last 5,500 years," writes Matthew Wooller, director of the Alaska Stable Isotope Facility, who participated in the analysis.

At this rate, conditions are now favorable for a completely ice-free Bering Sea, the authors conclude, highlighting an effect of consequences on the ecosystem.



Researchers: Surfboards with Bright Lights Could Deter Shark Attacks

This picture taken on October 16, 2024, shows surfers riding the waves on Maroubra Beach after authorities closed down two adjacent beaches in Sydney. (Photo by Saeed KHAN / AFP)
This picture taken on October 16, 2024, shows surfers riding the waves on Maroubra Beach after authorities closed down two adjacent beaches in Sydney. (Photo by Saeed KHAN / AFP)
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Researchers: Surfboards with Bright Lights Could Deter Shark Attacks

This picture taken on October 16, 2024, shows surfers riding the waves on Maroubra Beach after authorities closed down two adjacent beaches in Sydney. (Photo by Saeed KHAN / AFP)
This picture taken on October 16, 2024, shows surfers riding the waves on Maroubra Beach after authorities closed down two adjacent beaches in Sydney. (Photo by Saeed KHAN / AFP)

Covering your surfboard in bright lights sounds like an open invitation to great white sharks, but research released Tuesday by Australian scientists found it might actually stave off attacks.

Biologist Laura Ryan said the predator often attacked its prey from underneath, occasionally mistaking a surfer's silhouette for the outline of a seal.

Ryan and her fellow researchers showed that seal-shaped boards decked with bright horizontal lights were less likely to be attacked by great white sharks.

This appeared to be because the lights distorted the silhouette on the ocean's surface, making it appear less appetizing, AFP reported.

TRENDI "There is this longstanding fear of white sharks and part of that fear is that we don't understand them that well," said Ryan, from Australia's Macquarie University.

The study, published in the journal Current Biology, was conducted in the waters of South Africa's Mossel Bay, a popular great white feeding ground.

Seal-shaped decoys were strung with different configurations of LED lights and towed behind a boat to see which attracted the most attention.

Brighter lights were better at deterring sharks, the research found, while vertical lights were less effective than horizontal.

Ryan said the results were better than expected and is now in the process of building prototypes for use on the underside of kayaks and surfboards.

Australia has some of the world's most comprehensive shark management measures, including monitoring drones, shark nets and a tagging system that alerts authorities when a shark is near a crowded beach.

Ryan said her research could allow less invasive mitigation methods to be used.

More research was needed to see if bull and tiger sharks -- which have different predatory behavior -- responded to the lights in a similar way, the authors said.

There have been more than 1,200 shark incidents in Australia since 1791, of which 255 resulted in death, official data shows.

Great white sharks were responsible for 94 of those deaths.

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