MercoPress. South Atlantic News Agency

The plastic legacy has reached profusely to the bottom of the planet

Dr Emily Rowlands out on sea ice near the RRS Sir David Attenborough for sampling work. (Pic BAS)

On 5 June, UN World Environment Day, the campaign motto was “Beat Plastic Pollution”, and with very good reasons, we are surrounded by plastic pollution and a report from BAS indicates that at the bottom of the world, where few humans have ever set foot, an unwelcome visitor has arrived. Antarctica – the vast, frozen wilderness of ice and snow – is no longer untouched by humanity’s most persistent pollutant: plastic.

The continent we often imagine as Earth’s last unspoiled frontier now bears the invisible fingerprints of our throwaway culture. Researchers have documented microscopic fragments of plastics, not just in Antarctica’s snow and surrounding waters, but deep in the Southern Ocean and within the bodies of the marine life that calls these frigid waters home.

“Part of the challenge is that plastic is not just one type of pollutant,” explains Emily Rowlands, a marine ecologist at British Antarctic Survey. “It’s a whole suite of different polymers that have different impacts on animals when they’re ingested, and they can all interact differently in the environment.”

Emily should know. Her research delves into the impacts of plastic pollution, particularly how it interacts with other climate stressors and affects the ocean’s ability to sequester carbon in the deep sea – a critical process in our planet’s climate regulation. As she and her colleagues continue measuring humanity’s plastic footprint in this remote sanctuary, a question emerges: can understanding where plastic is help us reduce its devastating effects before it’s too late?

An invisible invasion

Picture a grain of sand. Now imagine something 2,000 times smaller – invisible to the naked eye. That’s a nano-plastic particle, the smallest form of plastic pollution. Its slightly larger cousin, microplastic (less than 5mm in diameter), can result from larger plastic items breaking down or be intentionally produced, like the microbeads once common in cosmetic products.

While previous studies had found microplastics in the Southern Ocean – typically at lower concentrations than other seas – a discovery in early 2025 shocked even expert research teams.

As part of the CUPIDO project led by Dr Clara Manno, Emily and other BAS scientists reported that finding microplastics in snow near some of Antarctica’s most remote fiel camps: Union Glacier, Schanz Glacier and even at the South Pole itself. Their methodology was painstaking. Snow samples were carefully collected, melted and filtered through fine paper. The particles captured were then analysed using high-resolution infrared techniques capable of identifying plastics as small as a red blood cell (11 micro-meters).

What they found was troubling: three common plastic types – polyamide used in textiles, polyethylene terephthalate found in bottles and packaging, polyethylene known for durability – along with synthetic rubber. All were present at much higher levels than anticipated, the highest concentrations that these plastics had been documented in such remote locations.

Interestingly, at a control site distant from research facilities, polyamide was absent, suggesting some contamination comes from researchers themselves – perhaps from clothing fibers, ropes or marker flags.

“More needs to be done to understand the sources of plastic pollution on this beautiful continent,” Emily says. “Finding a human plastic legacy in the snow in the most remote region of our planet underlines the need for nations to collaborate to enforce global plastic mitigation strategies.”

From krill to whales: plastic in the food chain

Most people remember the haunting images from BBC’s Blue Planet II – a turtle trapped in plastic, a stillborn whale – that catapulted plastic pollution into public consciousness in 2018. Since then, research publications on ocean plastic debris have increased more than fivefold according to UNESCO.

But the plastic problem extends far beyond these iconic species to the microscopic foundation of Antarctica’s marine ecosystem.

In 2023, BAS scientists discovered microplastics in the most abundant Antarctic zooplankton: krill and salps. These tiny creatures – krill (which resemble tiny shrimps) and salps (transparent, barrel-shaped invertebrates) – mistake microplastics for food while grazing on phytoplankton of similar size.

This sends ripples through the entire Antarctic food web. Krill are the primary food source for whales, penguins and seals, while salps are consumed by certain fish and marine birds. As plastic enters these organisms at the bottom of a short food chain, it likely transfers up the food chain to the region’s iconic wildlife.

Laura Wilkie Johnston, a marine biologist and PhD student who led the study, recalls the moment her team confirmed their suspicions after examining the digestive tracts of krill and salps collected off the coasts of South Georgia and Coronation Island.

Euphausia superba, better known as krill (Credit: Pete Bucktrout | British Antarctic Survey)
“Our discovery raises significant ecological concerns,” she says. “These species play an integral role in the Southern Ocean ecosystem and we don’t understand the impact microplastics have on them or the overall environment.

“We long believed that because of their remoteness, the Poles were less at risk from plastic pollution compared with elsewhere on our planet, so it is really quite shocking to have found evidence of it in such abundant life in Antarctic waters.”

The climate connection

The story of plastic in Antarctica isn’t limited to its effect on wildlife. There’s an unexpected climate twist that few outside scientific circles have considered.

Krill might be tiny individually, but collectively they equal approximately the same biomass as humans on Earth. These little creatures serve as mighty carbon processors. When they eat, digest and excrete phytoplankton in massive quantities, they help lock away atmospheric CO₂ in the Southern Ocean’s depths.

This natural carbon sequestration service is now under threat. The CUPIDO project team discovered that nanoplastics may alter the density of krill “faecal pellets”, reducing their ability to carry carbon to the ocean floor. In effect, plastic isn’t just harming the animals – it’s compromising one of nature’s mechanisms for fighting climate change.

In laboratory conditions, the BAS plastic team has observed how different ocean stressors compound each other. When comparing krill embryo development under different scenarios: clean water, water with plastic pollution, water with increased acidity, and water with both pollutants. Perhaps unsurprisingly, those exposed to both stressors fared worst. The embryos in clean water, predictably, showed the healthiest development.

Mapping the invisible threat

In a region already facing rapid climate change, understanding how plastic pollution interacts with other environmental stressors has become a matter of urgency.

Aidan Hunter, an ecological modeler at BAS, has pioneered a new approach to this complex problem. As part of the CUPIDO project, he’s created the first comprehensive map of microplastics threats in the Southern Ocean, identifying ecological hotspots where monitoring and mitigation efforts should be concentrated.

His innovative modelling technique overlays multiple datasets – krill distribution, phytoplankton presence, sea surface temperature and pH, shipping routes, research station activities, and existing microplastic measurements – to reveal where krill and plankton are most likely to encounter local plastic emissions, and where these emissions might worsen other environmental changes.

“We wanted to provide information to policymakers and environmental managers so they can prioritize and formalize efforts to monitor and mitigate plastic pollution,” Aidan explains. “The remoteness of this region makes monitoring a challenge, so by identifying where plastics are most likely to interact with the animals at the bottom of the food chain, we can maximize the value of sampling and research.”

This ground-breaking mapping effort, accompanied by an interactive online application, allows researchers to continue tracking impacts as microplastic pollution intensifies alongside other environmental stressors.

A not-so-pristine paradise

With no proven techniques for removing plastics from the environment at scale, and global plastic production continuing to rise, Antarctica’s plastic problem presents a sobering reality check about humanity’s reach.

The scientists who spend their careers studying this remote continent find themselves in the bittersweet position of documenting its contamination, while working to understand and perhaps mitigate the damage. Their research offers our best hope for protecting what remains of this once-pristine wilderness.(BAS)