The apparently barren ice of the Arctic can host huge bright green blooms of microscopic plantlike organisms underneath it — all hidden from satellites — suggesting that the Arctic Ocean is far more productive than previously thought, scientists find.

However, it remains unclear whether such fertility could have unexpected downsides for life in the Arctic, researchers said.

The single-celled organisms in question are known as phytoplankton, which possess the green pigment chlorophyll just as plants do, helping them live off sunlight. They are vital to life in the seas, serving as the basic food source for many ocean animals. Indeed, they are key to life on Earth — they account for about half of the total oxygen produced by all plant life.

Phytoplankton blooms spring up in the Arctic during the summer, when the sun is constantly above the horizon. Scientists have largely assumed that the growth and amount of phytoplankton was negligible in waters beneath the ice there, although there were hints of phytoplankton blooms under the ice in the Barents and Beaufort seas and the Canadian Arctic Archipelago.

“As someone who has been studying polar marine ecosystems for 25 years, I had always thought that the idea of under-ice phytoplankton blooms was nonsense,” said researcher Kevin Arrigo, a biological oceanographer at Stanford University in California. “There is simply not enough light getting through the ice into the ocean for them to grow.”

As it turns out, phytoplankton not only flourishes under thick layers of ice, but grows in numbers about four times higher under the ice than in the open water.

“The idea that phytoplankton can not only bloom under 3-foot-thick ice but that they can reach numbers that put their open-water counterparts to shame was a complete surprise,” Arrigo told OurAmazingPlanet. “It means we have to rethink many of our ideas about how the Arctic Ocean ecosystems function.”

Phytoplankton surprise

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