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Marine organisms help disintegrate a plastic bag into 1.75 million pieces

A study by UK’s University of Plymouth says that by tearing apart solid plastics, marinelife actually contributes to the spread of microplastics in the environment.

December 12, 2017   by Canadian Packaging staff

According to marine scientists at the University of Plymouth in the UK, marine organisms are able to tear apart a single plastic bag into 1.75 million microscopic pieces.

When introduced to biofilm, the activity was found to have increased fourfold.

The research team looked at Orchestia gammarellus, a type of amphipod that grows up to about 1.8 centimeters in length. Living in a wide range of habitats such as shallow waters, the intertidal zone, and in estuaries, the amphipod can be found in Norway and Iceland, coastal waters of Europe, all the way down to southwest Africa.

When the team observed the Orchestia gammarellus shredding a plastic bag into the microscopic microplastic parts, they realized that the amphipods were contributing to the spread of microplastics within the marine environment, rather than them simply being emitted from the water supply or forming through the physical and chemical break down of larger items.


The study’s concept was to determine if different types of plastic and the presence of a biofilm (a layer of organic material which accumulates over time) could change the rate at which such organisms broke down plastic debris.

The researchers monitored shorelines and its lab, recognizing that plastic bags were stretched and then torn by the Orchestia gammarellus… and proof that the plastic was being consumed when its fecal matter contained microplastics.

The study found that it didn’t matter on the type of plastic: conventional, degradable, biodegradable… the Orchestia gammarellus tore it apart with equal voracity. Biofilm, however, was torn apart four times quicker.

Previous studies led by the university have shown that more than 700 species of marine life have been found to have encountered plastic debris, with clear evidence that ingestion and entanglement causes direct harm to many individuals.

The full study – Ingestion and fragmentation of plastic carrier bags by the amphipod Orchestia gammarellus: Effects of plastic type and fouling load by D.J. Hodgson, A.L. Bréchon, and R.C. Thompson – is published in Marine Pollution Bulletin,

Image above shows a group of Orchestia gammarellus found under a rock. Image by Auguste Le Roux via Wikipedia.

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2 Comments » for Marine organisms help disintegrate a plastic bag into 1.75 million pieces
  1. It’s basic biology…YES, organisms cause mechanical break down. That’s what they do… the real issue isn’t just the number of pieces, it’s the chemistry & impact of those pieces. The Biofilm data was potentially misleading… Was the bio-film PLA (or some other compostable film) or bio-based PET? Two different material types with vastly different impacts chemically that should always be clearly qualified in journalism. Compostables should be more capable of having those little pieces assimilate into the environment (research required, depends on the chemistry). however conventional plastics are known to take LONG time, with some undesireable side effects. I appreciate the source link! Sooo important to get the science right.

    • I agree… we do know that organisms will eat plastic… my cat likes to chew on the plastic cola can connectors…
      The study notes that the microplastics are still an environmental issue… and I even wrote about microplastics being found inside some 40% of the fish in a six-lake test area in Japan. Microplastics are a health concern, so even if the visible mess of plastic floating in the ocean is removed, there’s still what lies “below the surface” so to speak. I recall back in the 70s, my school Science Fair project was on how long it took for things to decompose… back when it was called Ecology, man. Plastic was up in the hundreds of years to decompose.
      Susanna… thank you for taking the time to read and comment back. All the best!

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