Environment & Energy
Related: About this forumIn Winter Of 2017-18, SE Bering Sea Ice Failed To Form; Deep "Cold Pool" Also AWOL
Peggys data were a bit of a shock. From an anchored vantage point in an expanse of the southeastern Bering Sea west of Alaska, Peggy, or mooring M2, had monitored conditions in the water for 25 years. A line of sensors extended down more than 70 meters to where Peggy was tethered to the seafloor, collecting information on temperature, salinity and other properties of the water.
Most years, the waxing and waning of floating sea ice follows a consistent seasonal pattern that is reflected in Peggys data. By November, sea ice migrates in through the Bering Strait or forms in some parts of the Bering Sea. As a by-product of the sea ice formation, a large mass of cold, salty water begins to pool near the seafloor. In the spring, phytoplankton bloom, and by early summer, the sea ice begins to melt away. The cold pool, however, lingers through the summer.
With an average temperature just below zero degrees Celsius a few degrees colder than the surrounding water that deep, cold pool is central to the Bering Sea ecosystem. The cold pool is where Arctic cod take refuge, hiding from predators such as Pacific cod and pollock, which are less tolerant of the cold. The Arctic cod get fat on large, shrimp-like copepods and spawn their young. In turn, the fish keep polar bears and seals well-fed. But in the winter of 20172018, the sea ice never appeared. And Peggys data, along with that of other moorings, revealed that the cold pool was AWOL too. Alarm trickled through the ocean science community, researchers who study everything from the physics of the Bering Sea to the small creatures that live on the seafloor and the larger marine mammals at the top of the food chain. In December in Washington, D.C., at the American Geophysical Unions annual meeting, these researchers gathered to present their data, trade stories and ponder what it all means.
Were these findings a fluke? We dont yet have enough data to say whether the Bering Sea is increasingly likely to be ice-free, says Jacqueline Grebmeier, a biological oceanographer at the University of Marylands Center for Environmental Science in Solomons. But Grebmeier, who has studied seafloor life in the Arctic for more than 30 years, has a gut feeling, she says, that its not a one-off incident. I think its the beginning of change.
EDIT
https://www.sciencenews.org/article/bering-sea-ice-disappearing-arctic-ecosystems
OnlinePoker
(5,724 posts)Consistent southerly winds pushed warm air north all season and very little ice formed south of the Bering Strait. It's only in the last week or so that northerlies developed and some ice started developing, but it's weak and thin and won't last long. Extent for the rest of the Arctic was normal. Here's how it looked on the 1st of March and yesterday
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/images/2019/03_Mar/N_20190301_extn_hires_v3.0.png
ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/images/2019/03_Mar/N_20190315_extn_hires_v3.0.png