A team of scientists, led by Stanford’s Kevin Arrigo, broke through some of the Arctic ice last July as part of the NASA ICESCAPE mission and found the complete opposite—abundant life!

“If someone had asked me before the expedition whether we would see under-ice blooms, I would have told them it was impossible,” says Arrigo. “This discovery was a complete surprise.”

The researchers discovered an abundance of phytoplankton—microscopic life that forms the base of the marine food chain. Phytoplankton require sunlight for photosynthesis, just like plants. And sunlight has a tough time penetrating thick sea ice.

But that thick sea ice is changing. Not only are warmer temperatures thinning the ice, but as the ice melts in summer, it forms pools of water that act like transient skylights and magnifying lenses. These pools focus sunlight through the ice and into the ocean, where currents steer nutrient-rich deep waters up toward the surface. Phytoplankton under the ice evolved to take advantage of this narrow window of light and nutrients.

The phytoplankton displayed extreme activity, doubling in number more than once a day. Blooms in open waters grow at a much slower rate, doubling in two to three days. These growth rates are among the highest ever measured for polar 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.

The phytoplankton bloom discovered by Arrigo and his colleagues in the Chukchi Sea (just north of Alaska) extends tens of meters deep in spots and about 100 kilometers (62 miles) across.

“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,” Arrigo says. “These blooms could become more widespread in the future, however, if the Arctic sea ice cover continues to thin.”

The discovery of these previously unknown under-ice blooms could have serious implications for the broader Arctic ecosystem, including migratory species such as whales and birds. Phytoplankton are eaten by small ocean animals, which are eaten by larger fish and ocean animals.

“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,” Arrigo says. “If their food supply is coming earlier, they might be missing the boat.”

The research is published this week in Science.

Image: NASA

The Arctic sea ice always fluctuates with the seasons, with the maximum extent usually occurring between February 18 and March 31, before the “melting season” begins with rising spring temperatures.

The NSIDC research team believes this year’s annual maximum ice extent occurred on March 7. The maximum ice extent was 463,000 square miles below the 1979-2000 average, an area slightly larger than the states of Texas and California combined. The 2011 measurements were tied with those from 2006 as the lowest maximum sea ice extents measured since satellite record keeping began in 1979.

Because of the spiraling downward trend of Arctic sea ice extent in the last decade, some of the NSIDC scientists are predicting the Arctic Ocean may be ice free in the summers within the next several decades.

Virtually all climate scientists believe shrinking Arctic sea ice is tied to warming temperatures in the region caused by an increase in human-produced greenhouse gases in Earth’s atmosphere.

The seven lowest maximum Arctic sea ice extents measured by satellites all have occurred in the last seven years, said CU-Boulder Research Scientist Walt Meier of the NSIDC, who participated in the latest study. “I’m not surprised by the new data because we’ve seen a downward trend in winter sea ice extent for some time now.”

Scientists believe Arctic sea ice functions like an air conditioner for the global climate system by naturally cooling air and water masses, playing a key role in ocean circulation and reflecting solar radiation back into space, said Meier. In the Arctic summer months, sunlight is absorbed by the growing amounts of open water, raising surface temperatures and causing more ice to melt.

The NSIDC will make a formal announcement of their findings next month.

To learn more about the declining Arctic, please watch our recent Science in Action video about NOAA’s annual Arctic report card.

Image courtesy of University of Colorado

This is the first oceanographic research voyage sponsored by NASA.  The ICESCAPE (Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment) mission plans to take an up-close look at how changing conditions in the Arctic are affecting the ocean’s chemistry and ecosystems that play a critical role in global climate change.

NASA is hoping that this mission enhances the satellite data that already is collected of the area. More than 40 scientists, including six from Stanford University, will spend five weeks at sea sampling the physical, chemical, and biological characteristics of the ocean and sea ice.

According to today’s Stanford Report:

They will gather data on the state of the ice, the ocean and the microscopic plants and animals that dwell therein. The tiny organisms regulate the flow of carbon into and out of the sea, and the scientists are seeking to assess how the melting ice is affecting the organisms and ecosystem.

“The ocean ecosystem in the Arctic has changed dramatically in recent years, and it’s changing much faster and much more than any other ocean in the world,” said ICESCAPE chief scientist Kevin Arrigo, PhD, of Stanford. “Declining sea ice in the Arctic is certainly one reason for the change, but that’s not the whole story. We need to find out, for example, where the nutrients are coming from that feed this growth if we are going to be able to predict what the future holds for this region.”

(The Stanford team will be blogging about their adventures and research. You can follow them here.)