Biofouling in Antarctica

As the coldest and driest continent, Antarctica has a relatively small amount of biodiversity when compared with the rest of the world. The ecosystems which are found here, however, are now expected to begin feeling the disturbance of the growing number of ships which pass through the surrounding waters. The potential consequences on the local environment are the subject of new research by Dr Arlie McCarthy at the University of Cambridge. Harry Lewis was sent to find out more, and began by asking why we’re starting to see a larger number of ships pass through Antarctica in the first place...

Arlie - There's a process called biofouling, and that is where any part of the ship that is connected to the water gathers growth. This is because, in the seawater, there are all kinds of different lavie and early stages of different seaweeds and animals. And then it can take those to a new part of the world.

Harry - Are there enough of these ships to really make an impact or is it quite a small number?

Arlie - There are about 100 to 200 ships that visit Antarctica every year. Most of the ships that visit Antarctica or the Southern ocean are going there because that's where their destination is, like research vessels that are studying all different kinds of things related to Antarctica, whether that's ice and oceans or whales and penguins, or other animals that live there, or even tourist ships that visit Antarctica. And there are fishing vessels as well. Compared to the almost hundred thousand commercial shipping vessels on the ocean, it's a very small proportion. However, they're still large ships, and they can have quite a lot of organisms. Antarctica is the only place in the world that has no marine invasive species, and so every ship that arrives still has chance to introduce something new to Antarctica that wasn't already there.

Harry - Are there any species that we will be familiar with that spring to mind when we're talking about these invasive creatures?

Arlie - Things like muscles - the same muscles, essentially, as the ones you might eat in a restaurant or buy at the fish and chip shop. They grow really, really well on ships. People might also be familiar with barnacles and there are a few different kinds of barnacles as well.

Harry - And why are we worried about these being dropped off in locations that they wouldn't normally be found?

Arlie - We know from other parts of the world that non-native species can have drastic effects on local ecosystems. This could be that they change the way nutrients are cycled, or they could change the interactions between species - so they could outcompete other species. As for Antarctica, it's difficult to know exactly what effects any new species could have, but we know that things like muscles and some kinds of barnacles have no equivalent in Antarctica, which means that they have the potential to have a big effect.

Harry - Arlie, I feel like the idea of invasiveness and us taking animals that shouldn't belong somewhere from one location to another is quite well recorded. So what is it that you found that differs or that expands this knowledge?

Arlie - We found that the places that are most often visited by ships in Antarctica are also the places that are changing most with climate change, so they're getting warmer. Up until now, we've thought that the temperature and the environmental conditions in Antarctica have really been almost like a protective force field, preventing anything that didn't evolve in Antarctica from surviving there. But if those conditions are changing, then the potential for new species not just to be introduced but to actually survive and to thrive is changing as well.