Surviving an Ice Age may sound like an easy task for a penguin. However, a new study of how climate change has affected emperor penguins over the last 30,000 years found that only three different populations of penguins survived during the last ice age, and the Ross Sea in Antarctica was likely the refuge for one of the populations.
The findings, published in the journal Global Change Biology, found that while current climate conditions may be optimal for emperor penguins, past conditions during the last ice age were too harsh for the survival of large populations.
A team of researchers supported by Adventure Network International, examined the genetic diversity of modern and ancient penguin populations in Antarctica to estimate how they have changed over time.
The emperor penguin is well known for its adaptions to the cold and icy world of Antarctica. However, the team found that during the last ice age the population of emperor penguins was about seven times smaller than it is today and split up into three populations.
"Because of there being about twice as much sea ice during the last ice age, the penguins were unable to breed in more than a few locations around Antarctica," PhD student from Ocean and Earth Science at the Univ. of Southampton and coauthor of the study, Gemma Clucas says. "The distances from the open ocean, where the penguins feed, to the stable sea ice, where they breed, was probably too far. The three populations that did manage to survive may have done so by breeding near to polynyas - areas of ocean that are kept free of sea ice by wind and currents."
Researchers believe the Ross Sea to be one of the locations that harbored penguins during the ice age due to the fact that there are distinct genetic differences between the penguins that breed in the Ross Sea from other emperor penguin populations.
"Our research suggests that the populations became isolated during the last ice age," PhD student from the Australian Institute for Marine and Antarctic Sciences and another coauthor of the study, Jane Younger says, "pointing to the fact that the Ross Sea could have been an important refuge for emperor penguins and possibly other species too."
Climate change may affect the Ross Sea last out of all the regions of Antarctica. In fact, the area has actually experienced an increase in sea ice over the last few decades, although the pattern is expected to reverse by the end of the century.
Tom Hart from the Univ. of Oxford and one of the organizers of this study added that, "It is interesting that the Ross Sea emerges as a distinct population and a refuge for the species. It adds to the argument that the Ross Sea might need special protection."
