As ice recedes, Arctic researchers study wind effects on marine life

A U.S. federal research vessel will launch on a cruise this week to study how Beaufort Sea wind affects plant and animal life in a changing Arctic Ocean.

The Sikuliaq, owned by the National Science Foundation and operated by the University of Alaska Fairbanks, will depart Friday from Nome for the trip through the Bering Strait to waters on and off the continental shelf in the Beaufort.

Climate warming in recent decades has resulted in far less summer seasonal ice in the Beaufort, which stretches from the northeast coast of Alaska across Canada. East winds that formerly blew over sea ice now blow over open water, said Steve Okkonen, a physical oceanographer at the University of Alaska Fairbanks.

Wind drives water at the surface of the shallow continental shelf, at depths of about 91 metres, north to water off the shelf, which drops to depths of more than 3,050 metres.

The result is a phenomenon called "upwelling." Deep, cold water rises toward the surface carrying large concentrations of plankton, which scientists hypothesize will attract fish, especially Arctic cod. Large numbers of cod in turn attract beluga whale and seabirds that prey on cod.

Aerial surveys have shown belugas congregating on the shelf break, said Carin Ashjian, a senior scientist at Woods Hole Oceanographic Institution, who will serve as chief scientist on the cruise.

"What we hope to do, and what we're planning to do, is to basically document and describe how the physical forcing of the wind produces this favourable feeding environment for the beluga whales," she said Tuesday. "It's one thing to say, `Oh, they can find food along this shelf break.' But we want to find out why they find their food along the shelf break, with numbers."

Upwelling events in the Beaufort are projected to increase as sea ice continues to trend downward, Okkonen said. Last year the minimum sea ice for 2016 was recorded Sept. 10, when ice covered 4.14 square kilometres, tied with Sept. 18, 2007, for the second lowest minimum on records since satellite measurements began in 1978.

The lowest year on record was Sept. 17, 2012, according to the National Snow and Ice Data Center at the University of Colorado, when sea ice fell to 3.39 million square kilometres.

Wind covering a greater distance over open water becomes a greater force on the ocean.

"We have a much bigger fetch," Okkonen said.

Researchers on board the 80-meter Sikuliaq will record oceanographic conditions, sample for plankton levels and cod numbers, and survey marine mammals and seabirds.

The ship will sail transects in a box roughly 60 by 100 kilometres, starting 32 to 48 kilometres offshore.

The scientists want to share the research story with the public, particularly with Alaskans, and will offer a Facebook page, with reports from the vessel, titled, "Arctic Winds, Fish, Fins and Feathers."

Researchers from the University of Washington, the University of Rhode Island and the U.S. Fish and Wildlife Service will be on board. Researchers are scheduled to return to Nome on Sept. 18.