June 2, 2009

Satellite Images Of Poop Help Track Penguins

Scientists often struggle to discover colonies of emperor penguins in Antarctica, but a study on Tuesday revealed how following trails of penguin poop on satellite images could lead them to the source.

Antarctica has a landmass that it about one-and-a-half times larger than that of the US. To make matters worse for researchers, emperor penguins breed on sea ice, which experts predict will shrink in the future due to global warming.

"We know that emperor penguins rely on sea ice to breed - like the polar bears in the Arctic depend on sea ice for their hunting. Although the sea ice at the moment is reasonably stable, we know that in future decades it will decrease rapidly," said Peter Fretwell, a geographer at the British Antarctic Survey.

Estimates of the total number of penguins vary anywhere between 200,000 to 400,000 pairs, according to BAS. However, changes in the sea ice on which they breed can affect their breeding success and the size of the colony.

"We need to know where they are and to assess how many there are before we can really work out how threatened they are by climate change."

As colonies of penguins begin to mate on ice, they stay there for several months and leave a large reddish-brown poop stain that can be visible from space through satellite images, said researchers at BAS.

"We were mapping one of our bases on an ice shelf, and we knew there was a penguin colony close to there," Fretwell told BBC News.

"I was using a satellite image as a backdrop for the map and it happened to have a reddish-brown stain on one of the creeks that was a possible location for the emperor penguin colony."

"It was quite a lucky find because just a few months beforehand, we had made a mosaic of these satellite images of the whole of Antarctica, so we could go round and track all the colonies."

Scientists were able to use the images to track 10 previously undiscovered emperor penguin colonies. Additionally, they found that six already-known colonies had moved locations.

Fretwell said the find was scientifically important, despite the "lighthearted method."

"Now we know exactly where the penguins are, the next step will be to count each colony so we can get a much better picture of population size," said BAS penguin ecologist Phil Trathan.

"Using satellite images combined with counts of penguin numbers puts us in a much better position to monitor future population changes over time."


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