Rising temperatures could melt the Antarctic’s sea ice buffer, devastating its ecosystem as animals, diseases and debris drift from Africa and Australia, a new study says.
The study, published in the journal Global Change Biology, used simulations of ocean currents to track the paths of virtual objects released from different locations.
Simulations showed that objects from Australia, South Africa, South America and New Zealand reach Antarctica every year, and objects from islands in the Southern Ocean make landfall even more frequently.
“Material could be reaching Antarctica from much further north than previously thought,” said Dr Hannah Dawson, lead author of the study.
Although no invasive species have yet established themselves on Antarctic shores, research suggests that over thousands of years waves and ocean currents have carried objects to Antarctic shores from across the Southern Hemisphere.
“If organisms frequent there, the cold water and icy climate must be preventing them from settling,” Dawson said, “but this is changing.”
Previous plants and animals that arrived in Antarctica may have been wiped out by sea ice constantly washing up and rubbing against the shorelines, or they may have been unable to survive the cold.
But rising temperatures and melting sea ice make it easier for invasive species to establish on coastlines. For the third year in a row, Antarctic sea ice has declined to alarming levels.
With the number of plastic particles floating in the world’s oceans estimated to exceed 170 trillion in 2023, increased plastic pollution also means there is more debris available for animals to float away as they migrate south.
Drifting plastic can carry diseases such as ant and bird flu, while drifting kelp and seaweed can carry crabs, starfish and slugs, said study co-author Ceridwen Fraser, a biogeographer at the University of Otago.
“This is a real concern for Antarctic species,” she says. “If non-native species make their way to the warming Antarctic coast and successfully establish themselves there, they could have a survival advantage over native species, which tend to be slower growing.”
“They might outcompete the local species and the local species would probably be left without anything to do,” Dawson said.
The study found that the Antarctic Peninsula is the most vulnerable to colonization, with the majority of simulated objects landing on the northernmost tip of the continent.
According to Andy Hogg, director of the research facility ACCESS-NRI, some climate change models suggest that the peninsula will be the first part of the continent where temperatures rise enough to allow foreign species to colonize.
Hogg said the paper’s advanced modelling showed scientists needed to investigate what organisms from other continents could survive in Antarctic environments and coastlines.
Jordan Pitt, a marine mathematician at the University of Sydney, said the peninsula’s west coast is already largely free of sea ice in summer and would be a key area for researchers to monitor the arrival of species.
