Adélie Penguins and Sea Ice
Adélie penguins are one of only two penguin species that breed on the Antarctic continent (the other being Emperor penguins). Adélies build their nests on small stretches of land along parts of the Antarctic coast that are not ice-covered. The health and location of their colonies are directly related to the amount of sea ice (frozen seawater) nearby, as well as air and water temperatures and the presence of large marine predators, such as Minke whales, that compete for food. Adélies feed on krill and small fish in the ocean at the edge of the sea ice. If there is too much sea ice, the penguins have to walk too far to get food for their chicks, and the colony begins to decline.
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Penguins swimming at Cape Royds Colony Download Quicktime video file. Cape Royds is the southernmost breeding colony of any penguin species. Adélie penguins form their nests on land along the Antarctic coastline and nearby islands. The health and location of colonies are directly affected by the amount of sea ice near nesting sites. |
In recent years, environmental changes in and around their habitat have been occurring at a rapid rate. A strong Southern Annular Mode in the southern Atlantic, the presence of the Ozone ‘hole’ and the position of two pressure systems off the western coast of Antarctica have changes the wind patterns around the continent and increased the polar jet, thus changing how heat is distributed in the Southern Ocean and the extent and range of sea ice the Antarctic.
According to David Ainley, a marine biologist who has been studying Antarctic penguins for the past 20 years, this changing winds have pulled warm air from South America toward the Antarctic Peninsula — the tail of land closest to South America — and pulled warm air away from the Ross Sea, which is further south. Thus, there has been a decrease in sea ice extent around the Peninsula and an increase in sea ice extent in the Ross Sea; penguin populations on the Peninsula are decreasing, while those along the Ross Sea are increasing or remaining stable. While less sea ice on the Peninsula makes it easier for Adélies to get food, they are adapted to life in the cold and cannot survive well in warmer temperatures on the Peninsula.
One exception to colony growth in the Ross Sea is the Cape Royds colony — the southernmost penguin breeding colony in the world — where an iceberg grounded at the edge of the McMurdo Sound in 2000, locking the sea ice in the Sound and preventing penguins from being able to get to open water to feed — an effect that lasted six seasons. Over the past two years, the Cape Royds colony have again begun to grow.
According to Ainley, penguins are the “canary in the coal mine” of Antarctica: “Both species of penguins are moving big time. It’s not like a person moving to a new condo. Penguins are showing humans that they will soon need to be moving too.”
Emperor penguins are even more attached to sea ice: they breed on it! Learn more about the effects of climate change on Antarctic penguins at www.penguinscience.com.
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What does an Adélie penguin colony sound like? Thousands of chattering penguins are the backdrop for these three that have strayed to the edge of the colony to explore. Download Quicktime video file. |
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Penguins are very social birds that eat, migrate, breed and play together. Find out what life is like for these curious little creatures on the edge of the sea ice. Download Quicktime video file. |
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