Not so Happy Feet - Climate change and Emperor Penguins

Happy Feet Movie

Happy New Year everyone! Hope you had a great time celebrating with your family and friends!  Going to do a short and interesting post today since its New Years Day! So, I recently re-watched the movie Happy Feet (Christmas movie marathon with hallmates, what can I say) and thought – why not write a blog on the pretty well known icon of Antarctica?

As you may all know, the Antarctic Peninsula is one of the world’s most affected region in terms of climate warming. Temperatures at the west coast of Antarctic Peninsula have increased approximately 3 degrees in the past 50 years, which is nearly TEN times the average rate of warming worldwide reported by the IPCC !  Rapid climate warming has also been occurring in the Southern Ocean, where experts suggest that sea-ice may reduce by up to 25% (though there are large uncertainties and more research is needed to confirm this prediction).

There are currently around 600,000 Emperor Penguins in the Antarctic region, however, Jenouvier et al. 2014 estimated that by the end of the century this would reduce by 19%. Although, it is clear that sea ice coverage plays a large role on the predicted decline in penguin populations, but the mechanisms behind the changes observed are unclear. Some researchers suggest that it relates to how sea-ice coverage affects the population’s breeding, travelling, feeding and hunting behaviour.

Consequences of Reduction in Sea-Ice Coverage

Projected changes of Sea Ice Concentration between 20th and 21st century. Circles indicate location of each penguin colony and the colour represents its conservation status. Green represents 'Non threatened', Yellow indicates 'Vulnerable', Orange indicates 'Endangered', Red represents 'Quasi-Extinct'

Thinning of Sea-Ice

For the Emperor Penguin (Aptenodytes forsteri), their life cycle relies on optimal sea-ice coverage. During summer to late autumn, ice-cover acts as a platform to raise juveniles before chicks fledge, and for moulting adults to shed their feathers (Emperor Penguin's life cycle shown in the diagram below). Warmer temperatures, however, may cause ice sheets to break earlier, which sweeps chicks into the sea and drown them.

Diagram showing the life cycle of Emperor Penguins

Reduction in Food Sources

Antarctic Krill (Euphausia superba)

The Antarctic krill (Euphausia superba) is a vital species within the Antarctic food web, and a primary food supply for Emperor Penguins. A reduction in sea-ice coverage affects the reproduction and abundance of Antarctic krills, because these Antarctic krills preys on algae and phytoplankton that are found beneath sea ice. Nonetheless, the reduction of the Antarctic krill also has an indirect effect on Emperor Penguins, as krill abundance will presumably have an impact on its alternative preys, such as the squid and other fish species that also prey on krills.

However, on a more POSITIVE note…

Research published recently suggested that global warming is actually creating changes that benefit certain penguin species - the Adélie Penguins. Its population has increased by 135 times in the past 14,000 years, despite an observed reduction in sea-ice in East Antarctica where they reside. For example, in the Ross Sea, an 84% increase in Adélie Penguins has been recorded between 1983-2010, coinciding with the 543 meters retreat of glacier observed. Younger et al. 2015’s recent study showed that the observed trend of population increase recently is not accidental, as Scotia Arc Adélie penguins have previously also experienced an increase in population that coincided with the spread of ice-free habitat, as a result of climate warming after the Last Glacial Maximum. Some suggest that this is because when glacier retreats, more breeding sites become available that facilitates their nesting and foraging behaviour. However, whether Adélie Penguin population will continue to increase also depends on the availability of its preys, such as the Antarctic krill, which is currently uncertain due to the impacts of climate warming.

The Adéle Penguin

So, can penguins adapt to climate change?

Not a lot is known about the population’s ability to adapt to the rapid climate warming. Some researchers suggest that they can potentially respond either by adaptation through evolution or through dispersal in the future. However, paleoecological record shows very limited evidence of their capability to adapt through microevolution since penguins have a long lifespan,which results in slow adaptation. Hence, there is a higher chance that they will respond to climate warming by dispersal in the future. Although it is unlikely that colonies are able to move down south, however, there are currently 2 Emperor Penguin colonies that are residing on land instead of ice. This indicates a potential possibility for other colonies to relocate and reside on land as glaciers retreat and sea-ice coverage decreases. However, again, this depends on whether there are enough food sources available on land.

So, what will happen to these colonies? 

I guess only time will tell.

If you're interested in taking a break, here's a nice documentary on how climate change affects penguins:

Source: http://www.pbslearningmedia.org/resource/ipy07.sci.ess.watcyc.penguinscience/penguin-response-to-climate-change/