Major ecosystem shift in Arctic seas
Bering Sea at sunrise. Listen to a 9-minute podcast with Jackie Grebmeier from the new Earth & Sky Clear Voices podcast series. (Photo by ra64)
In Earth’s warming north polar region, entire ecosystems are moving north.
That’s according to Jackie Grebmeier, a scientist from the University of Tennessee at Knoxville. She is lead author on a study of the Northern Bering Sea, between Alaska and Siberia. Grebmeier told Earth & Sky that, over the past decade, ice in this northern sea has retreated earlier in spring and refrozen later in fall.
Clams form the base of the food chain in this region. As the cycle of ice melting and refreezing changes, less food for the clams is produced, and their population shrinks. Other species of clams move in. As a result, threatened sea ducks that feed on the clams are finding it difficult to survive.
Jackie Grebmeier: The other clams that are coming in are thicker shelled and have less meat. So basically, the birds are getting less bang for their buck. They have to dive, they have to expend so much energy, but what they’re bringing back for their net carbon is less.
Gray whales have changed their yearly migration patterns in this region, too. They’ve moved north into shared feeding grounds with other whale species, crowding them. Grebmeier said she expects populations of ice-adapted mammals – like walrus and polar bears – to decline.
She said she’s not yet able to predict a timeline.
Our thanks today to NOAA, the National Oceanic and Atmospheric Administration.
Jackie Grebmeier added: “I would say that we are seeing more of the warming in the polar regions, with the caveat of variability. And that’s one of the things about system changes: you tend to get more variability before you get to another state.”
“The polar regions are kind of the first indicators of what is happening as far as the warming, but I think the weather patterns and the differences we’re seeing around the world are ramifications of that.”
Additional Arctic research from the University of Tennessee
Western Arctic Shelf-Basin Interactions Project
NOAA’s Arctic Change Indicator Website
Our thanks to:
Jackie Grebmeier
Research Professor and Project Director
Dept. of Ecology & Evolutionary Biology
Marine Biogeochemistry and Ecology Group
University of Tennessee at Knoxville
Additional Teacher Resources
NOAA: Bering Climate
This NOAA web page provides extensive information on the Bering Sea, including links to essays by scientists, scientific data, photographs, and more.
NOAA: How Does Ice Cover Vary in the Bering Sea From Year to Year?
The Bering Sea supports one of the Worlds richest and most productive fisheries. Many scientists agree that the effects of climate change may first be seen in areas such as the Bering Sea. This article discusses why sea ice is one of the most important physical elements of the Bering Sea continental shelf. It also covers sea ice formation, changes in sea ice over time, and how changes in the sea ice affect the entire ecosystem.
NOAA: Arctic and Antarctic Activity Book
This activity book designed for young learners contains a wealth of information about life in the arctic and Antarctic. It includes coloring pages with accompanying species text, word searches, connect the dots, mazes, Mad Libs and more.
NOAA: Arctic Change
This website sponsored by NOAA provides information on the present state of Arctic ecosystems and climate in historical context. It includes a link to the Arctic Report Card 2007: An annual update of changing conditions.
Andrill Project Iceberg: Education and Outreach
Learn how eight educators from the United States, Italy, Germany, and New Zealand are working with the scientists in Antarctica to see how conditions on Earth have changed over millions of years. Teachers and scientists provide video journals and photographs.
