Sensitive people are losers

Antarctica: These are the winners and losers of warming

by Peter Carstens
The sea ice and glaciers are melting in the Antarctic. British researchers have found that while king penguins benefit, emperor penguins and humpback whales are left behind

Parts of the Antarctic are particularly hard hit by climate change: In the past 60 years, temperatures in the Antarctic Peninsula have risen by almost three degrees - three times faster than the global average. During the same period, the ocean surrounding the continent warmed up by one degree.

Rising air and water temperatures, shrinking glaciers, dwindling sea ice and acidification of the ocean are a problem for many animals that have been perfectly adapted to life in an extreme environment for thousands of years. Or even threatening the very existence.

Which animals suffer particularly from these dramatic changes in their sensitive ecosystems and which even benefit from them - researchers from the British Antarctic Survey have now investigated in a study.

The losers therefore include many large animal species, including humpback whales and the charismatic emperor penguins.

Critical for many animal species: krill as a food source

The problem for humpback whales is the food chain: unicellular algae live on the underside of the sea ice, on which krill's early stages of development feed. If the sea ice disappears, the crustaceans may also stay away. And these are the baleen whales' most important food source.

Other whale species, on the other hand, could benefit from the warming. The southern right whale, for example, does not feed on krill, but on copepods that live in the open sea.

While adelia and chinstrap penguins, like humpback whales, depend on krill, the emperor penguin is even directly affected by the receding sea ice. Because the largest of all penguins feeds on fish - but is dependent on the ice on which it gives birth to its young.

All living beings that raise their young on land or on the sea ice will also suffer from adverse weather conditions: The researchers expect heavier snowfalls due to the rise in air temperatures.

Temperature-sensitive marine life with limestone shells is also particularly at risk. Because by absorbing excess CO2 from the atmosphere, the seawater becomes more and more acidic. Building a lime shell or skeleton becomes more difficult in such an environment.

Winners: starfish, sea urchins and jellyfish

The king penguin is one of the clear winners of Antarctic climate change: its preferred prey fish will benefit from the receding sea ice. In addition, the retreat of the glaciers increases the breeding area for flightless birds.

Overall, according to the study's authors, ecosystems will change dramatically. But there will be more winners than losers. Animals that feed on the seabed or in the open sea (and not on krill) are therefore primarily advantageous: starfish, sea urchins and jellyfish. Many of them are pioneer species that colonized the habitats that were opening up around Antarctica after the maximum of the last glacial period 20,000 years ago, as co-author David Barnes explains.