From: baalke@zagami.jpl.nasa.gov   
      
   Elvia Thompson   
   Headquarters, Washington                   October 7, 2003   
   (Phone: 202/358-1696)   
      
   Krishna Ramanujan   
   Goddard Space Flight Center, Greenbelt, Md.   
   (Phone: 607/273-2561)   
      
   Mark Shwartz   
   Stanford News Service, Calif.   
   (Phone: 650/723-9296)   
      
   RELEASE: 03-315   
      
   ANTARCTIC PENGUINS THRIVE IN OCEAN  "OASES"   
      
        NASA satellite data was used for the first time to   
   analyze the biology of hot spots along the coast of   
   Antarctica. The biological oases are open waters, called   
   polynyas, where blooming plankton support the local food   
   chain.   
      
   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 tightly coupled the penguin   
   populations would be to the productivity of these polynyas.   
   Any changes in production within these polynyas are likely to   
   lead to dramatic changes in the populations of penguins and   
   other large organisms," Arrigo said.   
      
   The study, which appeared in a recent issue of the Journal of   
   Geophysical Research, used satellite-based estimates to look   
   at interannual changes in polynya locations and sizes;   
   abundance of microscopic free-floating marine plants called   
   phytoplankton, which are the base of the polar ocean food   
   chain; and the rate at which phytoplankton populations thrive.   
   Covering five annual cycles from 1997 to 2002, 37 coastal   
   polynya systems were studied.   
      
   The largest polynya studied was located in the Ross Sea   
   (396,500 square kilometers or 153,100 square miles; almost the   
   size of California). The smallest was located in the West   
   Lazarev Sea (1,040 square kilometers or 401.5 square miles).   
   Most polynyas, at their maximum area in February, were less   
   than 20,000 square kilometers (7,722 square miles).   
      
   Data from NASA's Sea-viewing Wide Field-of-view Sensor   
   (SeaWiFS) and NOAA's Advanced Very High Resolution Radiometer   
   (AVHRR) provided weekly measurements of chlorophyll and   
   temperature that were used in a computer model to estimate   
   phytoplankton productivity. The researchers found, taken   
   together, the Ross Sea, Ronne Ice Shelf, Prydz Bay, and   
   Amundsen Sea polynyas were responsible for more than 75   
   percent of total plankton production.   
      
   The researchers were surprised to find how closely connected   
   the Adelie Penguins were to the productivity of their local   
   polynyas. The more productive polynyas supported larger   
   penguin populations. The more abundant krill fed more   
   penguins, and the birds had shorter distances to go to forage,   
   which reduced exposure to predators and other dangers.   
      
   The NASA Oceanography Program, the National Science   
   Foundation, and the U.S. Department of Energy funded this   
   research. NASA's Earth Science Enterprise is dedicated to   
   understanding the Earth as an integrated system and applying   
   Earth System Science to improve prediction of climate,   
   weather, and natural hazards using the unique vantage point of   
   space.   
      
   For information about the research and images on the Internet,   
   visit:   
      
   http://www.gsfc.nasa.gov/topstory/2003/0930penguins.html   
      
   For information about Adelie Penguins, on the Internet, visit:   
      
   http://www.aad.gov.au/default.asp?casid=1654   
      
   -end-   
      
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