Antarctic icebergs are enemies of penguins – Le Figaro

The grounding of a giant iceberg in Antarctica bay requires penguins walking too long detours to reach the open water where they find their food. Nearly 150,000 have already disappeared.

From the pen of Jules Verne, the adventure would have made the happiness of the heroes Fur Country , of the great pioneers North trapped in an area proving to be an ice island adrift. The reality in Antarctica, is another: the stranding in 2010 in Commonwealth Bay, the giant iceberg B09B have caused the death of 150,000 Adelie penguins according to the New Zealand and Australian researchers who publish their work in Antarctic Science . And the future of penguin that live on this part of Antarctica seems bleak.

Known as the windiest territory on Earth, Commonwealth Bay also serves as a cradle for many species , the Adelie penguins. Because his ribs are usually ice-free, thanks to winds called “katabatic” (descendants winds blowing inland) that form “coastal polynyas’ (open water between the coast and the sea ice). In its waters, micro-algae grow, feeding on krill (small shrimp cold water), which in turn makes the delights of penguins living in two or three kilometers from the coast.

60 km walking

But since 2010, everything changed at Cape Denison: the giant iceberg stuck in the bay area of ​​the sea that separates the continent was covered by a thick ice. Penguins nesting there now have to travel to more than 60 feet kilometers to reach open water where they find sustenance. Or if they are excellent swimmers, these birds make poor walkers …

So the researchers repeated the statement he made a century ago by Sir Douglas Mawson. In 1913, the explorer had counted out more than 200,000 penguins. The figure seems to have remained more or less stable over the century, according to other statements made in the same place in 1931, then in 2011, a year after the arrival of the iceberg. But in December 2013, researchers found a “catastrophic decline” in the number of penguins, with “a few thousand at most birds, perhaps less than a thousand” on one of the nesting sites, and counted 5,500 nests on the other site. They described “hundreds of abandoned eggs,” a floor “littered with dried carcasses of chicks of the previous season,” unusually silent and apathetic young penguins and no semblance seek to establish a new home, sad omen for the future of the colony. Conversely, another site visited three days later, located 8 kilometers from open water, abandoned nests were much rarer, young parents were loud and aggressive, and single moult which sought to rely whipping.

extreme climate Events

the explanation, according to the authors, lies in the kilometers of ice that force adults to endless round trips “tabs” to join the free water. Too long for children, who need refueling every two days; too long for adults who sacrifice their chicks to keep their own weight.

In January 2014, PlosOne , French and US researchers made the same observation on another portion of the country washed by the Ross Sea and blocked for five years, for two giant icebergs. The effectiveness of penguins to find food decreased with excess ice, and the authors were concerned that extreme weather events will diminish the chances of survival of the colonies. The authors of the article published these days are concerned, meanwhile, that the people of Cape Denison disappeared within 20 years if B09B does not decide to leave the area.