Nathalie Rose Le François is at Palmer Station in Antarctica until August 19, 2016. For a five-month period she’s conducting research work on perfecting methods for breeding, incubating and larval rearing in Antarctic icefish species This third mission to the South Pole in the company of different specialists is allowing her to observe life on the frozen continent close up as well as the changes taking place there.
The sharp noise caused by the cracking and then the collapse of huge fragments of the Marr Glacier wall can be heard regularly in the area of the Palmer scientific research station. The inexorable retreat of the glacier, recorded over the past 50 years, has recently yielded a new island close by, which will be named in honor of an American colleague of mine, Dr. Detrich, with whom I’ve been collaborating since 2013.
The legendary climatic stability of the continent and coastal waters of the Antarctic, which has permitted the development of isolated biological communities unique in the world, is now in peril. Since 1950, the average wintertime temperature has gone up by six degrees Celsius, the fastest increase on the planet. Climatic warming has entailed a 40-percent reduction in the ice sheet along the coastlines of the Antarctic peninsula while shortening its duration by 80 days a year. The populations of krill, an elementary link in the Antarctic food chain for a number of species of whale, penguins and fish, are especially vulnerable to this shrinking of the ice sheet, essential to their survival and their reproduction.
A shell too thin
Climate change also brings with it the appearance of invasive species of crustaceans. Numerous mollusks and other Antarctic invertebrates have no protection against these invaders. Millions of years of isolation, sheltered from grinding shellfish, has not encouraged the development of species equipped with thick shells. Climate warming is creating a breach in the physiological barrier that intense cold presents, and which in previous times limited the presence of predators in the Antarctic.
To each penguin its own ice cover
Penguins are species that are highly sensitive to changes in the ecosystem. Variability in the marine environment is integrated into their life cycle because of their longevity and their broad geographic distribution. Since 1994, three penguin species have been found around Palmer Station: Adelie penguins, Gentoos and chinstrap penguins. Although very close genetically, these species have highly different habitat preferences. The Adelie penguin, the species best adapted to the conditions of the original Antarctic, looks for the presence of ice in the winter season, whereas the other two species avoid it. At Palmer Station, an important trend has been observed in the decline of the Adelie penguin populations, whereas there is growth in indices of abundance for chinstrap penguins (who appeared in 1976) and for Gentoos (appeared in 1994).
Complex relationships are at work, and the environment of the Antarctic peninsula is being subjected to unprecedented levels of ecological and climatic variability – which deserve our full attention and continued research work.