Microplastics hot spots found in greater quantities than ever before on seabed
Currents act as conveyor belts that concentrate microplastics in hotspots, study suggests
Dr Ian Kane, of the University of Manchester, was lead author of the study published in the journal Science.
Guardian ‘Scientists have discovered microplastics in greater quantities than ever before on the seabed, and gathered clues as to how ocean currents and deep-sea circulation have carried them there.
Microplastics – tiny pieces of plastic less than 5mm in size – are likely to accumulate most densely on the ocean floor in areas that are also biodiversity hotspots, intensifying the damage they may do to marine ecosystems, according to the research. The international research team found up to 1.9 million pieces in a thin layer near the seafloor covering just 1 sq metre. The discovery suggests that deep-sea currents act as conveyor belts that concentrate microplastics in hotspots, similar to the “garbage patches” visible on the surface in parts of the Pacific.
Those same hotspots are also key breeding grounds for marine life, such as filter-feeding ascidians, or “sea squirts”, which are particularly prone to microplastic ingestion, along with sponges and cold water corals. Polychaetes, or “bristle worms”, live within the upper layers of sediment and actively mine it, and so can ingest buried microplastics that are decades old, showing that even when the pollutants fall to the seafloor they are not out of harm’s way and still have an impact on key ecosystems. These biodiversity hotspots are also home to various fish species.’