A map showing the incredible level of travel to Antarctica has been released by scientists. The researchers say the continent's pristine ecosystems are under threat from invasive species that are "hitchhiking" on boats headed there for international shipping and tourism.
The team, from the University of Cambridge and the British Antarctic Survey, traced the movement of ships from around the world through Antarctic waters.
Published in the Proceedings of the National Academy of Sciences (PNAS), their study showed that tourism, fishing, research and supply shipping connected Antarctica to ports across the globe and threatened the introduction of invasive species to Earth's most remote continent.
Previously, only five key gateway ports to Antarctica in Argentina, Chile, South Africa, Australia and New Zealand were targeted for most bio-security efforts aimed at protecting the continent from invasive "hitchhiking" species.
A map published in the study showed international shipping connected many more ports directly with the continent, exposing its ecosystems to invasive species such as European shore crab, barnacles and mussels.
Professor David C. Aldridge, from the Department of Zoology at the University of Cambridge, told Newsweek that he and his colleagues had been surprised by their findings.
"It has been widely assumed that the five so-called 'Antarctic Gateway' ports are the primary routes for direct transport into Antarctica, and this is where most of the biosecurity effort has been placed," he said.
"Our study shows that many, many more ports connect both directly (58 ports!) and indirectly with the Antarctic. This means that not only should we be looking at increasing biosecurity at more ports, but also that ships could be introducing many species that we hadn't previously thought about due to their geographic origins, such as East Asia."
Aldridge also said that, as yet, there were no known invasive marine species in Antarctica, but that their findings showed that status could be at risk.
"[Antarctica is] the only remaining uninvaded region of the world's oceans. We consider it to be the final frontier of marine bio-invasions!" he said.
The scientists said Antarctica is largely protected from invasive species by its extreme climate and the strong currents that circulate in the Southern Ocean. However, several factors are changing those natural barriers.
"First, climate change is making conditions around Antarctica ever more suitable for non-native species to establish and spread," Aldridge said. "Second, boat traffic can bypass the natural barriers to dispersal. An additional concern is that reduction in sea ice, through climate change, means that species that would have been scoured from the hulls of ships can now hang on and get transported into the shallower habitats where they are more likely to find a suitable habitat to settle."
Study co-author Arlie McCarthy, also from the University of Cambridge's Department of Zoology, said these factors, which could jeopardize Antarctica's barriers to invasive species, were also connected.
"Species from outside Antarctica seem unlikely to survive in Antarctic waters. But climate change is changing that by warming the water temperatures and changing the ice conditions. Unfortunately, the areas visited most often by ships, happen to also be the areas of Antarctica that are warming fastest from climate change," she said.
While the scientists said they were not calling for any specific measures to be adopted by ships traveling to Antarctica, additional bio-security measures could be put in place at a number of international ports that connect shipping directly with the continent to help protect its eco-systems.
Tourists visiting Antarctica can also help protect its pristine wildernesses. "They should ensure that they follow their own personal biosecurity measures when moving between sites to ensure that no water or obvious organisms are transported on their clothing and equipment," Aldridge said.
McCarthy added: "If everyone who visits is consistently adopting the recommended biosecurity practices then far fewer sneaky stowaways will make it to Antarctica."
