The Antarctic is considered to be a pristine wilderness compared to other regions and was thought to be relatively free from plastic pollution.
But new findings by scientists from the University of Hull and the British Antarctic Survey have revealed that recorded levels of microplastics are five times higher than you would expect to find from local sources such as research stations and ships.
Microplastics are particles less than 5mm in diameter and are present in many everyday items such toothpaste, shampoo, shower gels and clothing. They can also result from the breakdown of plastic ocean debris.
The findings, published in the journal Science of the Total Environment, have raised the possibility that plastic originating from outside the region may be getting across the Antarctic Circumpolar Current, historically thought to be almost impenetrable, and contributing to Antarctic pollution.
Researchers say there is now an urgent need for international co-operation to give greater insights into pollution levels and develop measures to mitigate the problem.
Dr Catherine Waller, an expert in ecology and marine biology at The University of Hull and co-author of the research, said:
Antarctica is thought to be a highly isolated, pristine wilderness. The ecosystem is very fragile with whales, seals and penguins consuming krill and other zooplankton as a major component of their diet.
We know from other studies around the world that these small animals can eat microplastics but we are not sure what effect this will have on them or their larger predators.
Our research highlights the urgent need for a co-ordinated effort to monitor and assess the levels of microplastics around the Antarctic continent and Southern Ocean and will form the basis of a policy paper to be presented at the 2018 Antarctic Treaty Consultative Meeting, the body that governs Antarctica, next year.
The Southern Ocean covers approximately 8.5 million square miles and represents 5.4% of the world’s oceans.
The region is under increasing threat from fishing, pollution and the introduction of non-native species, while climate change is leading to rising sea temperatures and ocean acidification.
Concern is growing about pollution from floating plastic debris, which can be become entangled with or ingested by wildlife. In contrast, pollution by microplastics has received little scientific or regulatory attention, say the researchers.
Microplastics enter the oceans via wastewater and through the breakdown of plastic debris and have been shown to be persistent in surface and deep ocean waters and in deep sea sediments.
Tests have shown that a single polyester fleece jacket can release more than 1,900 fibres per wash, while around half of discarded plastics are buoyant in seawater and maybe subject to degradation by ultraviolet radiation and decomposition. More than half of the research stations in the Antarctic have no wastewater treatment systems, the research reports.
To estimate the level of microplastics currently in the Southern Ocean, the research team analysed existing data and samples taken from around the Peruvian base on King George Island.
It’s estimated that up to 500kg of microplastic particles from personal care products and up to 25.5 billion clothing fibres enter the Southern Ocean per decade as a result of tourism, fishing and scientific research activities. While this is negligible at the scale of the Southern Ocean, the researchers say it may be significant at a local scale.
The research was carried out in association with the Cientifica del Sur University in Peru.
Dr Huw Griffiths, a marine biogeographer with the British Antarctic Survey and co-author of the research, said:
The threats to marine ecosystems presented by microplastics have been identified as a major global conservation issue but major questions concerning plastic in the Southern Ocean remain unanswered.
Our understanding of the sources and fate of plastics in these waters is limited at best. Given the low numbers of people present in Antarctica, direct input of microplastic from wastewater is likely to be below detectable limits at a Southern Ocean scale.
However, microplastics generated from macroplastic degradation or transferred into the Southern Ocean across the polar front may be a major contributor to the high levels of microplastics recorded at some open ocean sites.
In addition to tighter regional regulation on the use and release of plastics in the Southern Ocean, we believe that a greater understanding of their distribution and impact is required. To understand fully the sources and scale of this pollution would require an internationally co-ordinated effort.