Microplastic Pollution Recorded in Antarctic Sea Ice

Credit: Anna Kelly
Plastic microfibers seen under a microscope. Credit: Anna Kelly

Published Apr 22, 2020 8:37 PM by The Maritime Executive

Microplastic contamination has been identified in Antarctic sea ice for the first time.

Published in the journal Marine Pollution Bulletin, the new study analysed an ice core collected in East Antarctica in 2009 and identified 96 microplastic particles from 14 different types of polymer. The pollution was documented by an Institute for Marine and Antarctic Studies-led research team, including researchers from the Australian Antarctic Division.

Lead author Anna Kelly said plastic pollution has previously been recorded in Antarctic surface waters and sediments as well as in Arctic sea ice, but this is thought to be the first time plastic has been found in Antarctic sea ice. “Forming from seawater, around 80 percent of Antarctic sea ice melts and reforms each year, providing seasonal opportunities for microplastics on the sea surface to become trapped in the ice,” she said. “The ice core we analysed was from coastal land-fast sea ice and averaged almost 12 particles of microplastic per liter. While this concentration is lower than that found in some Arctic sea ice samples, the 14 different polymer types we identified is only slightly less than the 17 found in Arctic studies.”

The microplastic polymers identified in the ice core were larger than those in the Arctic, which may indicate local pollution sources because the plastic has less time to break down into smaller fibers than if transported long distances on ocean currents.

Local sources could include clothing and equipment used by tourists and researchers, but some fibers were from varnish and plastics commonly used in the fishing industry.

Rather than sinking to the deep ocean, the entrapment of microplastics in Antarctic sea ice allows them to persist for longer near the sea surface, making them more available for consumption by marine organisms such as krill, a keystone species in Southern Ocean ecosystems, and consequently marine predators higher up the food chain.

“It is worth noting that plastic contamination of West Antarctic sea ice may be even greater than in our ice core from the East, as the Antarctic Peninsula hosts the bulk of the continent’s tourism, research stations and marine traffic,” Kelly said.