The research found a strong association between the well being of Adelie Penguin populations in the Antarctic and the productivity of plankton in the polynyas. Polynyas are areas of open water or reduced ice cover, where one might expect sea ice. They are usually created by strong winds that blow ice away from the coast leaving open areas, or by gaps appearing on the ocean's surface, when flowing ice gets blocked by an impediment, like an ice shelf.
The Antarctic waters are rich in nutrients. The lack of ice, combined with shallow coastal waters, provides the top layers of the ocean with added sunlight, so polynyas offer ideal conditions for phytoplankton blooms. Because the ice around polynyas is thin in the early spring when the long Austral day begins, they are the first areas to get strong sunlight. The open waters retain more heat, further thinning ice cover and leading to early, intense, and short-lived plankton blooms. These blooms feed krill, a tiny, shrimp-like animal, which in turn are eaten by Adelie Penguins, seabirds, seals, whales, and other animals.
Although relatively small in area, coastal polynyas play a disproportionately important role in many physical and biological processes in Polar Regions. In eastern Antarctica, more than 90 percent of all Adelie Penguin colonies live next to coastal polynyas. Polynya productivity explains, to a great extent, the increase and decrease in penguin population.
"It's the first time anyone has ever looked comprehensively at
the biology of the polynyas," said Kevin Arrigo, assistant
professor of Geophysics at Stanford University, Stanford,
Calif. "No one had any idea how tightl
Contact: Krishna Ramanujan
NASA/Goddard Space Flight Center