Kerry-Jayne Wilson, Chris S.M. Turney, Christopher J. Fogwill and Estelle Blair of the NZ West Coast Penguin Trust, and the University of New South Wales in Sydney, Australia, have reported on a tragic consequence of climate change. While the Arctic loses much of its ice, the other end of the earth has incredibly been gaining in sea ice. Basically, a huge ice mass landed on the coast of Commonwealth Bay at Cape Denison and blocked access to the sea for Pygoscelis adeliae, the AdÃƒ ©lie penguin. No chicks can be fed after hatching without a great trek across land.
Such natural experiments causing stranding require urgent investigation in East Antarctica, where extreme events are likely to decimate populations such as this large colony of AdÃƒ ©lies. This bay was rarely covered by sea ice (since 1911) as offshore winds monitor surface ice formation and sweep it out to sea. But recently, the calving of icebergs from the ice sheets may have increased. In December 2009, giant iceberg B09B grounded on the beach and has steadfastly remained since then. This causes sea ice about 3m thick to remain on the coast instead of being swept offshore. The penguins must then travel 60km (37miles) to find open water. The adults are dying off because of this long and icy journey they have to undertake, while all chicks have died since this time, as it would be impossible to provide enough food for their survival.
These birds have reduced in population to around 10,000 (5520 pairs) currently, with a previous estimate of 160,000.So far, that is a 94% reduction in numbers. In <20 years, the penguins will be gone, unless the sea ice begins breaking up again, or the iceberg moves. More colonies exist in the area with some AdÃƒ ©lie penguin colonies existing on the Bay’s eastern fringes. The heartbreak of seeing the animals struggle for existence must be truly empathetic for the scientists counting the dead and dying. The natural experiment is however of increasing significance, as many organisms can be involved in the ecology of such change. Global warming simply does not mean flood or drought, heat, or even colder weather. It means disruption on a global scale, including events we don’t even notice, in far-flung locations such as Cape Denison.
The paper is called
The impact of the giant iceberg B09B on population size and breeding success of AdÃƒ ©lie penguins in Commonwealth Bay, Antarctica, published in Antarctic Science this week.
Efforts by the British Antarctic Survey to mitigate penguin habitat loss were a little misplaced when we reported in August 2014 with Protecting penguins from habitat loss. The obvious problem in the east of Antarctica could be increased grounding of icebergs!