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MOSCOW, September 8, Tatiana Pichugina Last year, thousands of emperor penguin chicks drowned in Antarctica due to melting sea ice. Four of the five colonies in the Bellingshausen Sea lost offspring. Scientists predict extinction of the species by the end of the century if warming continues.
Depend on sea ice
There are 18 species of penguins on Earth. These flightless birds, which have mastered the ocean, live in the Southern Hemisphere. The largest are imperial: individual males reach 1.3 meters in length and weigh up to 40 kilograms.
All penguins swim and dive beautifully, but emperor penguins do it best. In search of prey, they travel hundreds of kilometers and can dive to a depth of more than 500 meters.
Of all the warm-blooded species in Antarctica, only emperor penguins lay and hatch eggs in winter. In the harshest months, the chicks hatch and remain under the care of their parents until molting. The cubs, covered from birth with soft gray down, will have to change their plumage to water-repellent ones — only after that they are ready for independent life. On average, raising chicks takes almost eight months.
Emperor penguins' entire lives depend on the first-year sea ice around Antarctica. Birds nest on it in colonies, rest, dive into ice holes in search of food, and hatch chicks. If the ice melts or breaks up earlier than usual, icebergs and islands may move ashore. However, over the past 70 years, only one such colony has been spotted in the world.
From January to March, adult penguins molt, and, unlike other birds, completely. For several weeks they are left without their water-repellent, insulating plumage and are unable to swim. During this time, they need a stable surface under their feet, and their body must have enough fat and nutrients to survive a long hunger strike. Reliable ice is also needed for the entire breeding period.
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Forecast until the end of the century
In 2021, a large team of scientists led by researchers from the Australian Antarctic Division published a forecast that within a century, emperor penguins will disappear as the ice around the continent melts.
The life cycle of these birds is highly dependent on the stability of sea ice. Thus, the second largest colony in Halley Bay lost its offspring for four seasons in a row due to too early melting. Ice may disappear due to the sliding of glaciers, breaking off large icebergs from them, blocking the ability to obtain food. In 2001, this led to the death of the colony along with its offspring at Cape Crozier in the Ross Sea. She began to recover only four years later. If warming continues at the current rate, the authors of the work argue, the conditions for successful reproduction of emperor penguins will become less and less and they will disappear.
There are currently approximately 236 thousand pairs of emperor penguins living on the continent in 60 colonies.
In a work published recently in Nature, scientists provide new facts to support their prediction. They observed five penguin colonies in the Bellingshausen Sea. They were discovered 14 years ago using satellite images and the number of individuals was counted with high accuracy.
In early December 2022, when the chicks fledged, the sea ice had already begun to melt. It was the Bellingshausen Sea that suffered the most — some parts of it were completely deprived of ice. As a result, four of the five colonies left their inhabited ice floes: they were not visible in the photographs. Considering that the chicks had not yet moulted and could not survive in the icy water, a significant part — about ten thousand — died. There are chances that someone took refuge on icebergs, for example, near Smiley Island. It is impossible to calculate the exact percentage from the images.
In the entire history of observations in this area, something similar has happened only once, but the scale of the current incident is unprecedented. “For the first time in 15 years of satellite observations, we have seen the loss of offspring due to melting sea ice. Although we expected something like this,” first author Peter Fretwell of the British Antarctic Survey told ABC News.
Not yet According to published data, one in five emperor penguin colonies lost their offspring last December. Scientists fear this season will be even worse, according to a graph of sea ice loss provided by the US National Snow and Ice Data Center.
Birds that have lost their offspring can next time form a colony in a more stable place, the authors of the work note. But if sea ice fails every season, this strategy will not work.
Linking a single anomalous loss of sea ice off the coast of the sixth continent to long-term climate change is difficult — there are only hypotheses and modeling results. For example, in the last two years, the extent of sea ice has decreased to the lowest level in 45 years of satellite observations. How far this extends to the entire continent and whether this trend will continue remains to be determined by climatologists. As for the anomalies in the Amundsen and Bellingshausen seas, they are so far assessed as regional and associated with the La Niña phenomenon, which greatly affects the Southern Hemisphere.