Looks like it’s plastic for lunch. For the first time, plankton have been caught on camera munching on tiny pieces of plastic. Verity White from Five Films and her team captured the video under a microscope at the Plymouth Marine Laboratory in the UK. They were inspired by Matthew Cole’s research investigating the impact of tiny grains of plastic litter on marine zooplankton. To see the problem for themselves, the team surrounded copepods – a type of zooplankton – with tiny fluorescent polystyrene beads between 7 and 30 micrometres in diameter, then observed how much of the foreign material they consumed. “We were looking inside just one drop of water,” says White. Zooplankton typically feed on algae suspended in water. They create currents with their legs to draw food towards them and have been shown to discriminate between different species of algae, using chemical and touch receptors. However, sometimes they can also consume similar-sized bits of plastic when they’re feeding. The video is filmed over three hours, during which time you can see the fluorescent beads moving through the copepods’ bodies. “The plankton were swimming and processing food non-stop,” says White. Millions of tonnes of plastic litter end up in the ocean every year and the effect on marine life is a growing concern. Among this debris are tiny particles from fragments of objects like buoys, floats or polyester fabrics or from additives in cosmetics. They contain toxic morsels that could be passed up the food chain if swallowed by organisms at the bottom. So far, Cole and his colleagues have seen that a range of zooplankton, including crab and oyster larvae, consume these microplastics. In some cases, the creatures excrete the plastic within hours, but it can remain in their intestinal tracts for up to seven days if the zooplankton don’t have access to food. The plastic hinders feeding by reducing the rate at which they can consume algae, which in turn can make it harder for them to survive and reproduce.
