A drastic impact of global warming is the melting of ice caps in the polar regions of Antarctica.?
While the resulting rise in sea levels is a grave concern for the planet Earth in general, Antarctica's penguins seem to be happier when there is less sea ice.
A new research points out that Adelie penguins, Antarctica's most common species of penguins, are able to travel to farther distances by swimming in ice-free waters. The penguins are thus able to access food more easily than before.
Scientists studying the region had a hint of the better survival conditions for penguins in low sea-ice. During sparse sea-ice, penguins tend to see an increase in population while considerable breeding failures were observed in the years with substantial increase in sea ice in the region.
The reason for the same, however, was unknown till now. The new research by researchers from Japan's National Institute of Polar Research now sheds some light on the mystery.
The team of researchers tagged 175 penguins in Antarctica with GPS devices and video cameras. This was to monitor their growth across four seasons in the region observing different sea ice conditions.
With the attached monitoring tools, the researchers were able to track penguins on their trips and observe their walking, swimming and resting behaviour. The inspection also offered an estimate to the amount of prey captured by the penguins during sea dives.
It is known that penguins, though slow on land, are swift swimmers. Yuuki Watanabe, from the National Institute of Polar Research, said: "For penguins, swimming is a whopping four times faster than walking,¡± as quoted in a report by Sky news.
"This may seem counter-intuitive, but the underlying mechanism is actually quite simple," said Watanabe. A simple reason is that penguins have a larger area under the water surface to swim when there is less sea-ice.
In such conditions, penguins can dive and swim in a wider area, often right from their nests, thus reducing their efforts to catch a prey. Another reason is that with less sea ice, more sunlight is able to enter the water, promoting the growth of underwater plankton that is the main food of the krill that the penguins feed on.
Thus an increased availability of food also reduces competition among the penguins for prey. Published in Science Advances, the study points out that the penguins conserve an average of 15% to 33% energy per trip compared with ice-covered seasons. The conserved energy then enables their growth and reproduction.
The research, however, warns that the conditions are only true for the penguins living on the main "continental" part of Antarctica. The species found on the thin Antarctic peninsula on the outskirts of the continent undergo just the opposite effects of a drop in sea-ice.