Skip to main content
Part of complete coverage on

Melting Arctic 'blooms' with algae

By Rose Hoare, CNN
June 11, 2012 -- Updated 0429 GMT (1229 HKT)
A satellite image of the Chukchi Sea, between Alaska and Russia, shows phytoplankton bloom (in green). A satellite image of the Chukchi Sea, between Alaska and Russia, shows phytoplankton bloom (in green).
Going green?
Phytoplankton found in the Arctic
Melt-water pools
Robots to find algae
  • A NASA expedition has discovered a huge phytoplankton bloom under Arctic ice
  • Scientists say melting ice pools function as skylights, enabling under-ice photosynthesis
  • The timing of such blooms could affect migratory species' feeding cycles

(CNN) -- Scientists in the Arctic have discovered the largest ever under-ice bloom of phytoplankton, likening the discovery to "finding the Amazon rainforest in the middle of the Mojave Desert."

Researchers were amazed to discover a colossal 100 kilometer (62 miles) stretch of phytoplankton blooming under Arctic ice, north of Alaska, in July last year.

It had previously been assumed that sea ice blocked the sunlight necessary for the growth of marine plants. But four times more phytoplankton was found under the ice than in ice-free waters nearby.

Scientists now believe that pools of melting ice actually function like skylights and magnifying glasses, focusing sunlight into sea water, providing the perfect conditions for the intense phytoplankton bloom, which makes the water look like pea soup.

Undiscovered until the 1970s, the ocean's phytoplankton is now understood to be responsible for about as much of the oxygen in our atmosphere as plants on land.

The ecological consequences of the polar bloom are not yet fully understood but given phytoplankton's position at the base of the food chain, it is expected to have implications for ocean animals that feed in the area.

This is like finding the Amazon rainforest in the middle of the Mojave Desert.
Paula Bontempi, NASA.

It was a serendipitous discovery for scientists who, as part of NASA's ICESCAPE program, were studying the impact of climate change in the Chukchi sea, where melt season changes are pronounced.

Making their way through meter-thick ice aboard the U.S. Coast Guard's largest icebreaker Healy in July last year, scientists observed surprising amounts of fluorescing chlorophyll, indicating the presence of photosynthesizing plant life.

Tide turns towards undersea energy

"If someone had asked me before the expedition whether we would see under-ice blooms, I would have told them it was impossible," said ICESCAPE mission leader Kevin Arrigo of Stanford University, at a press conference announcing the publication of findings in "Science" this month. "This discovery was a complete surprise."

Donald Perovich, a U.S. Army geophysicist who studied the ice's optical properties, described the under-ice area as looking "like a photographic negative".

"Beneath the bare-ice areas that reflect a lot of sunlight, it was dark. Under the melt ponds, it was very bright," he said.

The melt pools were found to let in four times as much light as snow-covered ice. Protected from ultraviolet rays, phytoplankton grows twice as fast under-ice as in the open ocean.

Using an automated microscope system called an Imaging FlowCytobot, Woods Hole Oceanographic Institution biologist Sam Laney took millions of photographs of the phytoplankton organisms, some of which he also found in brine channels inside the ice.

This discovery was a complete surprise.
Kevin Arrigo, Stanford University

Antarctic ice shelves 'tearing apart', says study

The type of phytoplankton found near coasts can bloom rapidly when there are changes to the amounts of light and nutrients available. Some blooms are toxic for humans and marine life.

If the Arctic sea ice continues to thin, blooms might become more widespread and appear earlier, which could pose problems for migrating birds and whales, said Arrigo.

"It could make it harder and harder for migratory species to time their life cycles to be in the Arctic when the bloom is at its peak," he said. "If their food supply is coming earlier, they might be missing the boat."

"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," he said.

Part of complete coverage on
January 21, 2013 -- Updated 0230 GMT (1030 HKT)
Patricia Wu looks at efforts to combat food waste in Hong Kong.
January 14, 2013 -- Updated 0233 GMT (1033 HKT)
CNN's Pauline Chiou goes to Hong Kong's annual toy fair to find out about the growing market for eco-friendly toys.
December 31, 2012 -- Updated 0415 GMT (1215 HKT)
CNN's Liz Neisloss reports on a roof that is only a sample of the greening of Singapore's skyline.
December 19, 2012 -- Updated 0216 GMT (1016 HKT)
A dam project in Cambodia could destroy livelihoods and ecosystems, says Conservation International
December 18, 2012 -- Updated 0322 GMT (1122 HKT)
Shipping lines, port authorities and technology companies are taking the initiative to go green and reduce costs.
December 10, 2012 -- Updated 0206 GMT (1006 HKT)
Less than 20 miles from Singapore's skyscrapers is a completely different set of high-rise towers.
December 6, 2012 -- Updated 1104 GMT (1904 HKT)
The Pitcairn Islands might only have 55 human inhabitants, but the waters surrounding them are teeming with marine life.
December 3, 2012 -- Updated 0322 GMT (1122 HKT)
Biofuel made from sugar cane waste in Brazil could revolutionize the global energy industry.
November 26, 2012 -- Updated 0258 GMT (1058 HKT)
Many believe that fuel-cell cars will overtake electric vehicles in the near future.
November 19, 2012 -- Updated 0820 GMT (1620 HKT)
Modern and sustainable buildings in the UAE are taking cues from an ancient Arabic design tradition.
November 12, 2012 -- Updated 0409 GMT (1209 HKT)
One man's artistic vision is distracting divers from Cancun's threatened underwater ecosystem.
November 12, 2012 -- Updated 1746 GMT (0146 HKT)
Lake Victoria, Africa's largest lake, has been plagued by water hyacinth plants for over two decades.
A turtle on Australia's Great Barrier Reef
Just how much are natural wonders like the Great Barrier Reef worth in monetary terms?