High Levels of Microplastics in the Arctic Sea Ice Alga Melosira arctica, a Vector to Ice-Associated and Benthic Food Webs

Plastic pollution has become ubiquitous with very high quantities detected even in ecosystems as remote as Arctic sea ice and deep-sea sediments. Ice algae growing underneath sea ice are released upon melting and can form fast-sinking aggregates. In this pilot study, we sampled and analyzed the ice algaeMelosira arcticaand ambient sea water from three locations in the Fram Strait to assess their microplastic content and potential as a temporary sink and pathway to the deep seafloor. Analysis by mu-Raman and fluorescence microscopy detected microplastics (>= 2.2 mu m) in all samples at concentrations ranging from 1.3 to 5.7 x 104 microplastics (MP) m-3 in ice algae and from 1.4 to 4.5 x 103 MP m-3 in sea water, indicating magnitude higher concentrations in algae. On average, 94% of the total microplastic particles were identified as 10 mu m or smaller in size and comprised 16 polymer types without a clear dominance. The high concentrations of microplastics found in our pilot study suggest thatM. arctica could trap microplastics from melting ice and ambient sea water. The algae appear to be a temporary sink and could act as a key vector to food webs near the sea surface and on the deep seafloor, to which its fast-sinking aggregates could facilitate an important mechanism of transport.

Automated summary

Plastic pollution is widespread, even in remote ecosystems like Arctic sea ice and deep-sea sediments. A pilot study found high concentrations of microplastics in ice algae Melosira arctica and ambient sea water from the Fram Strait. The microplastics could be trapped by the algae and act as a temporary sink and pathway to the deep seafloor.