Changing Sea Ice Conditions and Arctic Marine Ecosystems

The shrinking area of Arctic sea ice in summer is one of the most often cited examples of anthropogenic climate change. The areal extent of sea ice at the time of the September minimum has declined by about 1%/yr since satellite observations began 35 yr ago. Sea ice is very different from lake ice. A brine is created as ice crystalizes, a portion which remains in channels within the ice and provides habitat for microscopic plankton. These organisms include photosynthetic algae and microscopic animals that feed on the algae, and they then become food for shrimp and fish under and at the edges of the ice. This production is the base of the food web that supports marine mammals and birds that flourish in the Arctic during spring and summer. Climate models project that with additional warming from greenhouse gases summer sea ice could vanish in the Arctic by mid century, with profound implications for many iconic species. Bio: Professor of Biological Oceanography at Harvard and was President of the American Association for the Advancement of Science from Feb 2008-Feb 2009.[1][2] McCarthy is Alexander Agassiz Professor of Biological Oceanography and former Master of Pforzheimer House. He is also Acting Curator of the Malacology Department in the Museum of Comparative Zoology. His studies address factors that regulate the processes of primary production and nutrient supply in upper ocean, approached using controlled laboratory studies and field investigations. Study sites range from near shore to the open ocean. Recent and current field research sites include the North Atlantic, equatorial Pacific, and Arabian Sea.