EXPERT REACTION: First microplastics found in Antarctic snow

When we think of Antarctica, we often think of the last place on Earth untouched by humans. That is certainly what Ronald Amundsen believed when he raced to the South Pole in 1911. Only recently did scientists find that atmospheric pollution bet him there by two decades. Over a hundred years on from the race to the South Pole, Aves and colleagues (2022) discovered that microplastic pollution has invaded each continent on Earth including Antarctica. 

Likely sourced from nearby stations, but not ruling out remote Southern Hemispheric sources, Aves and co-researchers detected a range of microplastic polymer types, colours, shapes, and sizes in surface snow collected from multiple sites surrounding Ross Island in the Ross Sea region. Microplastics are lightweight and have a low density. These properties mean that relatively large microplastic particles can be transported a greater distance in the atmosphere than dust particles. 

Being an ice core scientist, I wonder what ice cores could tell us about the history of microplastic contamination in Antarctica. Are the microplastics in Aves’ samples a one-off occurrence or have microplastics been around Antarctica undetected for some time? 

While the atmospheric science community is only beginning to understand the uniqueness of natural atmospheric particles over the pristine Southern Ocean and Antarctica, a new source of synthetic particles in the atmosphere raises new questions regarding their influence on atmospheric processes and climate. How will microplastics impact wildlife in the largest marine reserve on Earth – the Ross Sea Marine Protected Area? Answering these questions is time critical and essential if we are to quickly act to mitigate the impacts of microplastics on climate and the environment.

Unfortunately I was not surprised to learn that microplastics have contaminated Antarctica, given their persistence in every other environment on Earth and easy distribution via the air. The sun in Antarctica is exceptionally harsh with gear degrading rapidly and fragments of plastics will inevitably spread. Best efforts are made, certainly by Antarctica New Zealand, to limit environmental contamination. Having studied airborne microorganisms in Antarctica I can attest that although most are locally derived, there is plenty of evidence that the circumpolar vortex does not block all intercontinental movement onto the continent and I would imagine that the contribution globally to microplastics in Antarctica will only increase as time goes on.

As a species we need to come to grips with the global impact we are having to our environment and the fact that many of these pollutants are transboundary – they do not stay localised to the site of production becoming someone else’s, and potentially all of our problem.

Any scientists I have met who have conducted research on the continent are acutely aware of how precious the continent is for scientific advancement and the conflict that comes from knowing that by learning more about it, you are damaging a small part of it. My supervisor explained it simply when I was doing my PhD there that everything you do there must justify the damage you will inevitably do so make the most of every second you have the privilege of conducting science in this unique place.

What this paper is doing is shedding light on the importance of understanding how much and where microplastics are coming into the continent. The impact of what they saw in the snow is likely similar to the impact in the terrestrial system – which is where 99.9% of the life in Antarctica is found. From my perspective as a microbial ecologist, that's really important.

For me what they found is not surprising given the proximity to the bases. They sampled recent snowfall and assumed that this would represent 'aeolian' sources (produced or carried by the wind) - but the wind blows continuously there, and likely mixes and sorts particles locally. I'd like to see stronger evidence for the idea that these plastics might be coming from offshore, but it's really hard to identify where microplastics come from. If in fact the sources for these plastics is off-continent, then I would expect that in the terrestrial environment, like the Dry Valleys where snowfall accumulates and sublimes, there should be considerable accumulation of microplastics. This would be an easy way to verify their hypothesis.

There have been a lot of changes in what we can bring down to Antarctica because we now know that things can get out of the bases. For example, the amount of styrofoam coming into the continent has been seriously reduced, if not eliminated. The same goes for wood and in some cases even cardboard where it can be replaced with plastic reusable containers.

Previously we did some work out in the McMurdo Dry Valleys with particle collectors, basically little wind vanes that have the ability to collect particles in the air. We set up eight of them into Miers Valley, and when we came back the next year, all eight of them had little styrofoam balls in them. That valley is 65 km from the bases and we were still picking up styrofoam out there which could have come from anywhere.

Scientific research is probably the greatest impact on the continent, and there's every reason to go to Antarctica for science. But we wanted to do some longer-term studies, so we recently built an environmental chamber to emulate the conditions of the Antarctic dry valleys. We re-ran some of our Antarctic field studies in the chamber, and we saw that the results were very similar. So now we can do experiments in four weeks in the chamber, which would normally take us four months or much longer to do in the dry valleys - without ever having to go and impact Antarctica.

Microplastics are being found in every environment, every ecosystem and every species so far tested. This includes in some of the most remote and uninhabited places on earth. So this study, sadly, confirms what we expected. It really is impossible for any organism to now avoid the impacts of human activity, similar to the way that all environments and organisms are impacted by human-driven climate change. Plastic pollution (of all sizes) not only is an impact on the scale of climate change but also is intimately entwined with it – from the extraction of fossil fuels for plastic production to the recently identified role atmospheric microplastic particles play in the reflection and trapping of heat.

Whilst research around the impacts of nano- and microplastics is still in its infancy, they are being seen to affect organisms and ecosystems in a variety of ways. It is therefore of concern that yet another remote ecosystem is exposed to more impacts resulting from human activity.

Until some significant steps are taken to reduce the use and management of plastics, the levels of plastic pollution in the environment are going to continue to rise, and the levels of nano- and microplastics will continue to rise for a significant period, as all the plastic already out there continues to fragment but doesn’t really go away completely. This highlights the need for the UN’s global treaty to ban plastic pollution. Treaties, policies, and regulations each take time, but we can all do a lot of things today that change and reduce the pressure of plastic pollution upon the environment - of which we are a part.