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Plastic

First evidence of plastic microfibre consumption by deep-sea animals

Paper: Taylor, ML, Gwinnett, C, Robinson, LF, Woodall, LC (2016).  Plastic microfibre ingestion by deep-sea organisms.  Scientific Reports: 33997.  doi: 10.1038/srep33997

100% Polyester fleece jacket. (Image credit: Megan Chen)

100% Polyester fleece jacket. (Image credit: Megan Chen)

Plastic has amazing and convenient qualities: it’s cheap, durable, lightweight and waterproof.  We use it for many things such as grocery store bags, containers, furniture, and we even weave it together to make synthetic fabrics for our clothes. Unfortunately, plastic doesn’t decompose via living organisms, or biodegrade, it just breaks down into smaller and smaller pieces to become microplastics.  Microplastics are small pieces of plastic less than 5 mm in length.  They include plastics broken down from larger pieces, as well as microbeads–small plastic beads found in some face wash and shampoos, and microfibres–small thread-like pieces that are found in clothing like fleece jackets. Unlike microbeads, which have been banned in several countries, we are just starting to detect and assess microfibre presence in the environment.  Turns out, when we wash clothing made from synthetic fabrics such as acrylic and polyester, tiny fibers are shed.  Because microfibres are so small, they can escape wastewater treatment plants and enter waterways.  Once in the water, plastic tends to ‘collect’ or adsorb pollutants, metals and bacteria that could negatively affect marine life if ingested.  Studies have already shown that microplastics are inadvertently eaten by animals that live in the open ocean such as tuna and whales and are present in our seafood; however a lot less is known about the existence of microplastics in the deep sea in part due to the logistical challenges of researching in such an extreme environment.  The discovery of microplastics in deep sea sediments was covered previously on oceanbites here, but for the first time ever, scientists have found evidence that deep sea animals are actually consuming plastic microfibres.  

 

Image 1: crosses represent all known sites with plastic microfibre contamination present in sediment samples. White circles locations where animals in this study were collected.

Figure 1: Crosses represent all known sites with plastic microfibres found in sediment samples. White circles represent sites where animals in this study were collected from. Figure used with permission from Taylor et al., 2016

To conduct this study, nine deep sea animals including an anemone, two sea cucumbers, two soft corals, a squat lobster, two zoanthids (small anemone-like polyps) and a hermit crab were collected with a suction hose and mechanical arm of a remotely operated vehicle (ROV) during expeditions in the Southwest Indian Ocean in 2011 and mid-Atlantic in 2013, see the white circles in Figure 1.  The animals’ stomach, mouth, internal cavities and respiratory organs were then dissected and studied under a microscope.  Due to the nature of the study, contamination prevention was a priority.  Anyone handling the specimens wore clothing only made from natural fibres, non-plastic tools were used, and damp filter paper was used to detect microplastic contamination near the dissection area.  Furthermore, strict lab protocols were followed based on forensic laboratories that analyze fibres evidence.

 

Figure 2: a) sea pen and b) hermit crab in their habitat before being collected taken by Taylor, ML. c) polyester microfibre and d) acrylic microfibre found within deep sea animals, taken by Gwinnet, C. (Figure used with permission from Taylor et al., 2016).

Figure 2: a) sea pen and b) hermit crab in their habitat before being collected taken by Taylor, ML. c) polyester microfibre and d) acrylic microfibre found within deep sea animals, taken by Gwinnet, C. (Figure used with permission from Taylor et al., 2016).

Five types of plastic microfibres: modified acrylic, polypropylene, viscose, polyester and acrylic, were found in six out of the nine ocean animals collected including a sea cucumber, squat lobster, sea pen, hermit crab and two zoanthids, see Figure 2.  Plastic microfibre consumption seems to be happening across many different types of animals, since microfibres were found across three different phylums (cnidaria–sea pen, zoanthids, crustacea–squat lobster and hermit crab & echinodermata–sea cucumber).  It is also occurring in animals across different feeding strategies as plastic microfibres were found in filter feeders, scavengers and predators.  While the sample size of this study is small, it appears that microfibre pollution makes up the majority of microplastic pollution in the deep sea, yet most feeding experiments conducted in labs use microbeads or plastic shavings.  Furthermore, ingestion of plastic microfibres by deep sea organisms may hold many consequences for individual animals and for ecological communities as a whole if this problem is pervasive.  Chemicals used in roughly half of all plastics have been identified as hazards by the United Nations, and that is not even including plastic’s known property for adsorbing other pollutants, metals and bacteria.

 

This study shows that our plastic problem can reach even the most remote habitats on Earth, such as the deep sea.  And while we don’t quite know the full extent of what we’re dealing with, it’s our responsibility to protect and manage the problem before it gets worse.  There is a device being released soon by the Rozalia Project that is meant to be thrown into your laundry machine to capture microfibres before they enter the wastewater treatment system, but perhaps we could design better wastewater treatment plants to capture them.  Or, is it a completely crazy idea to turn to natural fibres or develop and use better fabrics that will biodegrade over time?  Regardless, seeing that there is already evidence that microplastics are entering our diets through seafood, but also through poultry and swine that are fed fishmeal, we need to address this issue to secure the safety of our food, our health and the ecosystems we depend on.  

Megan Chen
I graduated with a Masters of Coastal & Marine Management from the University of Akureyri in Iceland, and am currently working at the Smithsonian Institution’s National Museum of Natural History in Ocean Education. I am interested in smart and feasible ocean solutions, especially in fisheries management, and the incredible adaptations marine life has come up with. In my spare time, I like to stargaze, watch talks on random topics and explore different corners of the world.

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