lunes, 25 de junio de 2012

Coming Soon: A World without Penguins



The threat of extinction hangs over penguins. Care2 bloggers have written about the precipitous drop among the Adélie and African penguins. While the film “March of the Penguins” was popular, a lot of attention focused on the 13 species of penguins (out of 18) that are threatened or endangered.

In the last week researchers have raised the specter of global warming as the culprit responsible for the precipitous decline of two species of Antarctic penguins: the Emperor and the Chinstrap.

Woods Hole Oceanographic Institution (WHOI) biologist Stephanie Jenouvrier has been studying the Emperor penguin and reports the Dion Islets colony dropped from 150 breeding pairs in 1948 to none in 2009. She and her colleagues warn that if global temperatures continue to rise, the Terre Adélie penguins may also disappear.

The species relies on sea ice for breeding and raising their chicks. Disappearing ice increases the already high mortality among Emperor chicks. It also robs them of their food source, in a chain of losses that starts with plankton that grows beneath the ice and moves through the krill, squid and fish that feed on the plankton.

Jenouvrier says: “Our best projections show roughly 500 to 600 breeding pairs remaining by the year 2100. Today, the population size is around 3000 breeding pairs.


As for the chinstrap penguins, a report in “Live Science” indicates scientists have been taken by surprise over the loss of more than a third of the breeding colony of Deception Island. In the 1990s they predicted warming temperatures would lead to larger numbers because the chinstraps prefer ice-free waters.

Unfortunately, they are dependent on the same food web that feeds the Emperors. When the ice disappears, so does dinner. Andres Barbosa of the National Museum of Natural Sciences in Madrid says:

This is an example of how the human activity far from the poles can affect the life at thousands of kilometers far from our homes. Therefore, a more responsible use of the energy and the fossil fuels is necessary to preserve the planet and then the Antarctica.

He also points to the harmful effects of tourism, overfishing and even research as factors in the decline of penguin colonies.

Hal Caswell, the WHOI senior mathematical biologist who collaborated with Stephanie Jenouvrier on the Emperor penguin study says:

We rely on the functioning of those ecosystems. We eat fish that come from the Antarctic. We rely on nutrient cycles that involve species in the oceans all over the world. Understanding the effects of climate change on predators at the top of marine food chains—like Emperor penguins—is in our best interest, because it helps us understand ecosystems that provide important services to us.

Penguin colonies are in a steady decline. Human behaviors are at fault. The question remains whether we can change those behaviors fast enough or whether future generations will grow up in a world without penguins.


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