Plastic waste may get into whole new realms -- the deep ocean, for instance -- by being distributed in the (apparently yummy) feces of plankton.
If plastic is spread by the tiny, microscopic organisms that are at the base of the marine food chain and reach far into the ocean's depths, it could really have an impact.
The new finding is from a study by the University of Exeter and Plymouth Marine Laboratory.
In that research, the scientists learned that zooplankton, those tiny marine creatures, ingest "microplastics" -- debris made of plastic and smaller than a millimeter in size. They do this readily, and later the plastic is voided from the body in fecal pellets.
Already, one purpose of fecal pellets in the marine environment is to transport nutrients and carbon into greater water depths. This provides food to animals within the water column and helps circulate and store carbon.
But when plankton eat polystyrene microplastics, their feces are lighter than usual and sink more slowly. In that case, there's a heightened chance they'll be consumed by animals. In that case, the animals would be eating the plastic and spreading it further.
The new study has the first evidence that polluting the ocean with plastic is resulting in a different density, structure and falling rate in animals' fecal pellets.
"The magnitude of change observed here is concerning. We believe the impact of plastic contamination in the ocean deserves more detailed investigation and the team now hope to carry out further work in the natural environment," study lead Dr. Matthew Cole of Exeter said. "As these fecal pellets sink, they take the plastic with them. This could be an important route by which floating plastic litter is removed from the sea surface down to the ocean depths."
The study took place in a laboratory, so Cole says that the next step will be to make sure the results also apply to zooplankton in their natural habitat. Their research was conducted using copepods, which are a group of zooplankton that are ecologically important and are significant in the food web. The microscopic animals were given fecal pellets laden with microplastics, which they ate and ingested. This result demonstrated that other animals can indirectly eat the microplastics by eating the fecal pellets.
-Follow Catherine on Twitter @TreesWhales