By Winnie Courtene-Jones
Pictures: Winnie Courtene-Jones and Peter Lamont
Microplastics are small fragments of plastic, typically smaller than 5mm in size. They are found in different shapes and colours (pictures below). Microplastics occur as larger plastics fragment into ever smaller pieces or are intentionally manufactured to be small, for example in some exfolianting washes and toothpastes. Plastic is a durable material so when it enters the environment it persists and doesn’t just go away.
Microplastics can be found in vast quantities in the world’s oceans; in some surface waters microplastics can outnumber plankton! Plankton are the small organisms that support life in our oceans. This poses a threat to marine animals which can accidentally eat microplastics. Once eaten by an animal, microplastics can be retained inside that animal and are passed up the food chain and may ultimately reach humans.
The deep sea has long been considered a pristine environment, an area which is ‘out of sight out of mind’. However the deep sea faces a number of human impacts, including plastic and microplastic pollution. Have microplastics made it down into the deep sea? Have they been accidentally eaten by the animals living there? How do the amounts of microplastics eaten vary between different types of animals? For example, brittle stars are scavengers but bivalves filter the water to extract food.
We hope to start addressing these questions using the creatures collected during this research trip (see earlier post about collecting samples from the deep sea). The oceanographic data from the Extended Ellett Line and other measurements in the North Atlantic will also help to assess how long it takes for microplastics to make it down to the deep sea floor and how the ocean currents distribute microplastics.