Climate change puts the bite on penguins
PENGUINS are the cuddly faces of the Southern Hemisphere and among the most recognisable birds to brave the chilly Southern Ocean.
But ike so many other favourites of the animal kingdom – especially those that inhabit the world’s coldest places – they’re starting to suffer the effects of climate change.
The king penguin, an iconic black, white and yellow bird second only in size to the emperor penguin, is among the latest species to feel the heat.
King penguins raise their chicks on the sub- Antarctic islands north of Antarctica and dive for fish in the frigid waters at the northern reaches of the Southern Ocean. But their breeding and foraging behaviours may be at risk as ocean temperatures rise in the southern hemisphere.
New research shows that warmer sea-surface temperature can cause changes in the marine environment where they feed, forcing the birds to travel farther and dive deeper for their food – and causing decrease in their populations.
Climate of the southern Indian and Atlantic oceans depend on several factors.
These include the influences of El Niño and La Niña, which cause phases of warmer and cooler temperatures, as well as changes in atmospheric conditions in the southern hemisphere.
This can cause sea-surface temperatures to rise and fall from one year to the next.
These temperature changes can change marine ecosystems by driving fish and other organisms into different regions.
King penguins typically forage for food in an area of the Southern Ocean known as the Antarctic polar front, a region where the colder water in the south meets the warmer water to the north and draws an abundance of plankton, krill and fish.
In some years, though, if seasurface temperatures in the northern part of the Southern Ocean get too warm, the polar front can be pushed southward.
This means king penguins have to travel farther from their island homes to get to the best feeding areas.
The research says having to travel so much farther on foraging trips could have damaging effects on the king penguin population.
Researchers Charles Bost of the Chize Centre for Biological Studies at the French National Centre for Scientific Research, tracked the foraging patterns of king penguins living on the Crozet archipelago in the southern Indian Ocean between 1992 and 2010.
They wanted to find out how sea-surface temperature changes might affect the birds’ foraging behaviour, and whether changes in their behaviour could also affect their population sizes and breeding.
The researchers found that in warm years, the Antarctic polar front shifted south forcing the penguins to travel farther to get to their prime feeding grounds.
This is a problem for the birds during breeding season, when penguin parents take turns incubating eggs and raising chicks and must travel back and forth between the islands and the polar front much more often to relieve their partners of parenting duties.
It is time- consuming and exhausting.
In 1997, the southern Indian Ocean experienced an unusual El Niño-driven warming event.
The researchers observed that they also dove about 30m deeper for their food in this year compared with other years.
Many penguins did not survive these extreme conditions.
This is worrying news, because the king penguins won’t be the only species affected; seabirds or seals, will likely also be affected.
KID KING: A King penguin chick at The Aquarium at Moody Gardens in Galveston, Texas.
ENDANGERED: King penguins are threatened by global warming, which is cutting down their food supply.