NASA scientists say they've made a discovery in the Arctic Ocean 'as dramatic and unexpected as finding a rainforest in the middle of a desert'.
When its Icescape expedition punched through three-foot thick sea ice, the team found waters richer in the microscopic marine plants known as phytoplankton than any other ocean region on Earth.
The expedition explored Arctic waters in the Beaufort and Chukchi seas along Alaska's western and northern coasts onboard a US Coast Guard icebreaker.
"Part of NASA's mission is pioneering scientific discovery, and this is like finding the Amazon rainforest in the middle of the Mojave Desert," says Paula Bontempi, NASA's ocean biology and biogeochemistry program manager in Washington.
"We embarked on Icescape to validate our satellite ocean-observing data in an area of the Earth that is very difficult to get to; we wound up making a discovery that hopefully will help researchers and resource managers better understand the Arctic."
Phytoplankton, are the base of the marine food chain, but were thought to grow in the Arctic Ocean only after sea ice had retreated for the summer. Scientists now think that the thinning Arctic ice is allowing sunlight to reach the waters under the sea ice, allowing the plants to bloom.
"If someone had asked me before the expedition whether we would see under-ice blooms, I would have told them it was impossible," says Kevin Arrigo of Stanford University.
The blooms extended an astonishing 72 miles into the ice pack. They were extremely active, doubling in number more than once a day - more than three times faster than blooms in open waters. Researchers estimate that phytoplankton production under the ice in parts of the Arctic could be up to 10 times higher than in the nearby open ocean.
And the doscovery could be good news for the planet, as fast-growing phytoplankton consume large amounts of carbon dioxide. It does mean, of course, that scientists will now need to reassess the amount of carbon dioxide entering the Arctic Ocean.
"At this point we don't know whether these rich phytoplankton blooms have been happening in the Arctic for a long time and we just haven't observed them before," says Arrigo. "These blooms could become more widespread in the future, however, if the Arctic sea ice cover continues to thin."