A study of emperor penguins and how they have responded to climate changes over the last 30,000 years has found that the animals came close to extinction during the last ice age. According to the researchers only three populations of the animals may have survived that period with one taking refuge in the Ross Sea.
During the cool period, the team believes that much of Antarctica was too cold even for penguins and that the Ross Sea may have sheltered them for thousands of years.
Thanks, in no small part, to the 2005 documentary March of the Penguins their ability to adapt to the harsh conditions of the Antarctic are well known. The animals travel over 60 miles across the sea ice to lay their eggs, huddle together to survive winter storms and go long periods without food. All animals, however, have their limits.
A team of researchers, including scientists from the universities of Southampton, Oxford, Tasmania and the Australian Antarctic Division, examined genetic diversity among the animals to examine how their populations may have changed over time.
The team found that conditions during the last ice age may reduced the emperor penguins to one-seventh of their current populations, leaving only three populations who were able to find refuge from the harsh conditions.
“Due to 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. 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,” said Gemma Clucas, a PhD student from Ocean and Earth Science at the University of Southampton in a statement.
Clucas is one of the authors of the paper, published in the journal Global Change Biology.
The Researchers believe that the Ross Sea is one of the polynyas that supported an emperor penguin population through the last ice age was. That population also appears to have been isolated from the others. The team’s analysis showed that the Ross Sea penguins are genetically distinct from other Antarctic emperor penguin populations.
“Our research suggests that the populations became isolated during the last ice age, pointing to the fact that the Ross Sea could have been an important refuge for emperor penguins and possibly other species too,” said Jane Younger, a PhD student from the Australian Institute for Marine and Antarctic Sciences and the other lead author of the paper.
The Ross Sea seems to be a good refuge for Antarctic animals in all weather. During the current period of melting glaciers and global warming, the area has actually seen an increase in sea ice over the last few decades. Once again it is serving as a refuge for Antarctic life though the Ross Sea too is expected to suffer from climate change by the end of this century.
Despite the Ross Sea refuge, emperor penguins are once again in peril. This time it is due to loss of sea ice and global warming. While they have not officially been given “endangered species” protection yet many researchers have suggested that it is past time they were.
“If sea ice declines at the rates projected by the IPCC climate models, and continues to influence Emperor penguins as it did in the second half of the 20th century in Terre Adélie, at least two-thirds of the colonies are projected to have declined by greater than 50 percent from their current size by 2100. None of the colonies, even the southern-most locations in the Ross Sea, will provide a viable refuge by the end of 21st century,” said Stephanie Jenouvrier, a biologist with the Woods Hole Oceanographic Institution (WHOI).
Further evidence of hardship faced by penguins during the last ice age can be found in the February 16 edition of Current Biology. The authors of that paper showed that the cold temperatures appear to have robbed penguins of their taste buds and that the animals can probably not taste the fish that makes up the bulk of their diet anymore.