More emperor penguins in Antarctica than previously thought
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E-mail Xinhua, April 14, 2012
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| Emperor penguins [File photo] |
There are twice as many emperor penguins in Antarctica than was previously thought, according to a new study published Friday in the journal PLoS ONE.
In the journal, scientists describe how they used Very High Resolution (VHR) satellite images to estimate the number of penguins at each colony around the coastline of Antarctica. Using a technique known as pan-sharpening to increase the resolution of the satellite imagery, the science teams were able to differentiate between birds, ice, shadow and penguin poo (guano). They then used ground counts and aerial photography to calibrate the analysis.
These birds breed in areas that are very difficult to study because they are remote and often inaccessible with temperatures as low as -50 degree Celsius.
"We are delighted to be able to locate and identify such a large number of emperor penguins," said lead author and geographer Peter Fretwell at the British Antarctic Survey (BAS). "We counted 595,000 birds, which is almost double the previous estimates of 270,000 to 350,000 birds. This is the first comprehensive census of a species taken from space."
On the ice, emperor penguins with their black and white plumage stand out against the snow and colonies are clearly visible on satellite imagery. This allowed the team to analyze 44 emperor penguin colonies around the coast of Antarctica, with seven previously unknown.
"The methods we used are an enormous step forward in Antarctic ecology because we can conduct research safely and efficiently with little environmental impact, and determine estimates of an entire penguin population," said co-author Michelle LaRue from the University of Minnesota.
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