Non-native species are hitching rides to Antarctica on plastic debris

Antarctica, the final frontier on Earth, may not be as secluded as we once believed. New findings suggest that this pristine landmass, known for its unique species and ecosystems, is facing a significant threat: the unwelcome arrival of non-native species.

These invasive species are hitchhiking on floating debris such as marine pollution from Southern Hemisphere landmasses.

Unwanted visitors on a voyage

Scientists from the University of New South Wales, ANU, University of Otago, and the University of South Florida have found that floating objects from unexpected places could very well be Trojan horses for invasive species in Antarctica’s waters.

“An increasing abundance of plastics and other human made debris in the oceans means there are potentially more opportunities for biota to reach Antarctica,” said lead author Dr. Hannah Dawson, who is now based at the University of Tasmania.

Non-native species reaching Antarctica

Scientists have long known that small marine invertebrates and other non-native species could reach Antarctica by hitching a ride on floating objects like kelp, driftwood, pumice, and plastic.

Prevailing wisdom suggested that these species only drifted from remote and unpopulated islands in the Southern Ocean.

However, this new research paints a broader picture, revealing that these species can reach the Antarctic coastline from all southern continents.

Oceanic traffic patterns

“The longest journey was for objects released from South America,” said Dr. Dawson. The breadth of these new sources is beyond what was anticipated.

“We knew that kelp could raft to Antarctica from sub-Antarctic islands, such as Macquarie and Kerguelen Islands, but our study suggests that floating objects can reach Antarctica from much further north, including South America, New Zealand, Australia, and South Africa,” noted Dr. Dawson.

Antarctic ecosystems and invasive species

Southern bull kelp and giant kelp, some of the potential transporters of non-native species, pose a potential double threat to Antarctica’s marine ecosystem.

“Southern bull kelp and giant kelp are very big – often more than 10 m long – and create forest-like habitat for a lot of small animals, which they can carry with them on the long rafting trips to Antarctica,” explained Professor Crid Fraser from the University of Otago. “If they colonize Antarctica, marine ecosystems there could change dramatically.”

Movement of floating debris

The team analyzed surface current and wave data spanning from 1997 to 2015 to track the movement of floating debris from various Southern Hemisphere land sources towards Antarctica.

“We were able to analyze how frequent these rafting connections are by simulating dispersal pathways across 19 years of differing oceanographic conditions,” said study co-author Dr. Adele Morrison.

“We found that rafting objects reached the Antarctic coastline in each of the years simulated. There seems to be a constant bombardment of anything that floats – whether it’s kelp or a plastic bottle.”

Climate change and Antarctica species

The research also sheds light on the Antarctica regions most at risk from non-native species. Most of these sea-borne invaders are likely to land at the tip of the Antarctic Peninsula.

This area has relatively warm ocean temperatures and frequently ice-free conditions, which are ideal for non-native species to become established. The recent dramatic reduction in Antarctic sea ice makes these findings even more alarming.

“If the recent decline in Antarctic sea ice continues, then living things floating at the surface or attached to floating objects could have an easier time colonizing the continent, which may have big impacts on ecosystems,” said Dr. Dawson.

Raising awareness

With the understanding that Antarctica and it’s native species may not be as protected from marine invasion as previously thought, it’s time to rethink our actions and their wider impact.

As we stand at the brink of potentially irreversible changes in one of the most unique ecosystems on earth, the findings from this study may very well shape the decisions we make tomorrow.

Let us pledge to be more conscious about our waste disposal choices and take small steps today. After all, the ripple effect of these steps might just save an entire ecosystem tomorrow. What’s your next step going to be?

The study is published in the journal Global Change Biology.

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