NASA Discovers Unprecedented Blooms of Ocean Plant Life
Jun 07, 2012 | by Maria-José Viñas | NASA
Scientists have made a biological discovery in Arctic Ocean waters as dramatic and unexpected as finding a rainforest in the middle of a desert. A NASA-sponsored expedition punched through three-foot thick sea ice to find waters richer in microscopic marine plants, essential to all sea life, than any other ocean region on Earth.
The finding reveals a new consequence of the Arctic's warming climate and provides an important clue to understanding the impacts of a changing climate and environment on the Arctic Ocean and its ecology. The discovery was made during a NASA oceanographic expedition in the summers of 2010 and 2011.
The expedition called ICESCAPE, or Impacts of Climate on EcoSystems and Chemistry of the Arctic Pacific Environment, explored Arctic waters in the Beaufort and Chukchi seas along Alaska's western and northern coasts onboard a U.S. Coast Guard icebreaker. Using optical technologies, scientists looked at the impacts of environmental variability and change in the Arctic on the ocean biology, ecology and biogeochemistry.
"Part of NASA's mission is pioneering scientific discovery, and this is like finding the Amazon rainforest in the middle of the Mojave Desert," said 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," Bontempi said. "We wound up making a discovery that hopefully will help researchers and resource managers better understand the Arctic."
The microscopic plants, called phytoplankton, are the base of the marine food chain. Phytoplankton 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, catalyzing the plant blooms where they had never been observed. The findings were published today in the journal Science...
...Previously, researchers thought the Arctic Ocean sea ice blocked most sunlight needed for phytoplankton growth. But in recent decades younger and thinner ice has replaced much of the Arctic's older and thicker ice. This young ice is almost flat and the ponds that form when snow cover melts in the summer spread much wider than those on rugged older ice.
These extensive but shallow melt ponds act as windows to the ocean, letting large amounts of sunlight pass through the ice to reach the water below, said Donald Perovich, a geophysicist with the U.S. Army Cold Regions and Engineering Laboratory in Hanover, N.H., who studied the optical properties of the ice during the ICESCAPE expedition.
"When we looked under the ice, it was 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," Perovich said. He is currently visiting professor at Dartmouth's Thayer School of Engineering.