Australian scientists found the first evidence that climate change in eastern Antarctica affects terrestrial ecosystems: colder, windy and dry weather negatively affects mosses and changes their species composition. The study is published in the journal Nature Climate Change.
West Antarctica and the Antarctic Peninsula are among the places on Earth where the temperature grows faster than average, however, in eastern Antarctica there is no warming – on the contrary, the climate there becomes colder, windy and drier. Nevertheless, scientists also associate these processes with the global climate change caused by human activities and with the destruction of the ozone layer (a seasonal ozone hole arises annually over the Antarctic, which in recent years has been decreasing due to efforts to combat ozone-depleting compounds).
Sharon Robinson of the Australian University of Wollongong observed the mosses for 13 years growing next to the Casey national polar station on the Windmill Islands in eastern Antarctica. These mosses are considered to be the largest plant ecosystem in the region and have been dubbed the “Daintree Antarctica” by analogy with the Dainty Rainforest in Australia.
Scientists expected that any changes in the state of mosses would be gradual. “We were very surprised when we saw how quickly the ecosystem changed. After a pilot study in 2000, we started a continuous monitoring three years later. When we returned there in 2008, all these thickets of moss from green turned red, which indicates a strong negative impact. The change was very sharp, “said Robinson, who is quoted by the press service of the university.
The reason for this is the reduction in precipitation. If in 2000 the predominant moss species was Schistidium antarctici , which can for a long time carry immersion in water (in the summer the thickets near Casey station are often flooded), then by 2013 there appeared two new species, Ceratodon purpureus and Bryum pseudotriquetrum , preferring dry conditions and less resistant to flooding.
In addition, according to the stems of mosses, many of which grow for several centuries, it is possible, as in the annual rings of trees, to determine in which climate they grew. Having determined the age of moss with the help of radiocarbon dating, the scientists found out that now the weather conditions for them are substantially drier than in the 1960s. Finally, data on long-term weather observations, which are maintained in the Antarctic by the Australian Meteorological Bureau, testify to a more dry climate. Scientists also note that because of the ozone hole, the polar jet current has shifted to the south and intensified, which protects eastern Antarctica from warming.According to the authors, their research shows that there are no places on the Earth where it would be impossible to observe the consequences of climate change. “We regard Antarctica as untouched wildlife, but climate change and depletion of the ozone layer have a huge impact on it. What we do in the rest of the planet affects plants and animals in Antarctica, “Robinson said.
Recently, scientists have built on the basis of satellite data the most detailed map of Antarctica – now its image is more accurate than that of any other continent of our planet. This, in particular, will help to track the melting of glaciers in its western part.