Discovery could affect all marine life in the Arctic

Stanford scientists aboard an icebreaker in the Arctic’s remote Chukchi Sea have discovered a massive bloom of the microscopic marine plants called phytoplankton beneath the sea ice — a discovery that could affect the life of every seagoing creature in the Arctic, they reported Thursday.

The abundant plankton, they say, will force scientists to rethink long-held assumptions about the Arctic’s ecology, and could open up a major new food source for humans.

Kevin Arrigo, a biologist and oceanographer at Stanford’s School of Earth Sciences, together with Donald K. Perovich of Dartmouth University and a large team of colleagues, reported their discovery in the online journal Science Express.

Arrigo was leading a research cruise aboard a Coast Guard icebreaker two summers ago, intending to study phytoplankton in the open ocean, about 200 miles west of the Alaskan coast.

At the edge of the sea ice, the scientists aboard saw a massive bloom of plankton where they never had before. The bloom continued for at least 60 miles underneath the ice.

Instruments showed the tiny plants doubled in number every day, turning the otherwise clear water “a thick, pea soup green,” Arrigo said.

The plants are thriving in part because the Arctic sea ice has been thinning for years, a result of global climate change, Arrigo said. Melted ice water that pools atop the thin ice sheet makes it easier for sunlight to penetrate into the water, stimulating the growth of the phytoplankton.

In the Chukchi Sea, essential nutrients like nitrogen, phosphates and trace elements are abundant for the rapidly multiplying plants, Arrigo said.

Various species of phytoplankton form the crucial diet for many marine organisms and some whales. They make up the base of the entire Arctic food chain, supporting fish, walrus, seabirds and more.

The thriving plankton bloom could eventually give rise to a vibrant fishery, providing a new food resource for humans, the scientists believe.

The ice itself was between 2½ and 4 feet thick where the phytoplankton cells were growing, Arrigo said — and to their astonishment they found the plankton bloom was at least four times greater than in the open water.

“The mass of phytoplankton we found was truly astounding,” Arrigo said. “It was the most intense I’ve ever seen in my 25 years of research in the Arctic. It was a complete surprise.”

“It’s a pure discovery,” Perovich added, “and now we have an entirely new ocean.”