Tiny plankton snacking on plastic is a big problem for the food chain

In a short film that shows the dangers of marine pollution, tiny zooplankton can be seen ingesting plastic microbeads.

Michelle Starr Science editor
Michelle Starr is CNET's science editor, and she hopes to get you as enthralled with the wonders of the universe as she is. When she's not daydreaming about flying through space, she's daydreaming about bats.
Michelle Starr
3 min read

Zooplankton and flourescent plastic microbeads. Screenshot by Michelle Starr/CNET

The effect of plastic microbeads -- found in toothpaste and exfoliants -- on microscopic marine life is unknown. But thanks to filmmaker Verity White, we can clearly see that zooplankton are ingesting the microbeads along with their normal diet of phytoplankton.

The footage is part of a six-minute film from Five Films called "Ren Kyst - Got a Spare Afternoon?" about litter and coastal cleanups that late last month won the Atkins CIWEM Environmental Film of the Year from the Chartered Institution of Water and Environmental Management in the UK.

An estimated 8 million metric tons of plastic makes its way into the oceans every year, according to a study from the UC Santa Barbara National Center for Ecological Analysis and Synthesis, published in the journal Science this year. Somewhere between 6,350 and 245,000 metric tons of that plastic is floating -- which means the rest of it ends up somewhere beneath the surface.

And it's not all plastic bottles, six-pack rings and fishing nets. Some of the plastic that ends up in the ocean comes from the plastic microbeads found in body wash and other personal care products. Other discarded plastics degrade into similarly tiny fragments.

While it is estimated that plastics cause the death of over a million seabirds and 100,000 marine mammals every year, the effect they have on life under the ocean's surface is difficult to gauge.

The Plymouth Marine Laboratory in Plymouth, England is studying the impact that microplastics have on marine life, with a particular focus on zooplankton. "Ren Kyst," which is Norwegian for "Clean Coast," includes footage shot at that lab.

The action takes place in a single drop of water over the course of about three hours, condensed down into less than a minute of footage, reports New Scientist. Several copepods -- a type of zooplankton -- were surrounded by microscopic fluorescent polystyrene beads.

Copepods feed by moving their legs to direct food towards their mouths. While they can reject the wrong type of phytoplankton (algae), the film clearly shows some of the beads get caught up and ingested by the animals.

Ingesting the plastic can cause problems for the zooplankton. It can remain in their bodies for up to seven days, which negatively impacts the rate at which the zooplankton can consume algae, which in turn could impact their ability to survive.

This situation, according to the film, is a cause for concern not just for the zooplankton, but for other species as well. Zooplankton are at the bottom of the food chain. So if zooplankton populations drop, the animals that eat zooplankton will have a harder time finding food. Moreover, what zooplankton ingest often ends up ingested by their predators, all the way to the top of the food chain.

The Plymouth Marine Laboratory has released this week a suite of videos and other educational materials on the impact of microplastics on the ocean. You can find them online here. Below are the winning video and the zooplankton footage.

Correction, 7:15 a.m. PT: The reference to Ren Kyst has been fixed.