A new study from researchers in the United Kingdom and Greenpeace has found microplastic fragments in every one of more than 100 sea turtles studied in the Atlantic and Pacific oceans and Mediterranean Sea.
Scientists from the University of Exeter and the Plymouth Marine Laboratory said that while it's not clear what specific impact eating the microsized — less than 5 millimeters — plastic particles have on the turtles, they said it was disturbing that every turtle had the material in their guts.
Researchers said the tiny polymer pieces could be pathways for other contaminants.
"The effect of these particles on turtles is unknown," said Emily Duncan, lead author and researcher at the university's Centre for Ecology and Conservation. "Their small size means they can pass through the gut without causing a blockage, as is frequently reported with larger plastic fragments. However, future work should focus on whether microplastics may be affecting aquatic organisms more subtly."
She said that the fragments could carry contaminants, bacteria or viruses or impact the turtle at a cellular or subcellular level. The study examined seven major species of sea turtles.
Exeter professor Brendan Godley, senior author of the study, said other environmental problems may pose a bigger danger to the turtles, but the widespread presence in turtle digestion systems shows the need for better waste management.
"At the moment, this is not the main threat to this species group but it is a clear sign that we need to act to better govern global waste," he said. "It really is a great shame that many or even all of the world's sea turtles have now ingested microplastics."
The study said microplastics are "less of a concern" for the turtles than eating larger pieces of plastics or being caught in fishing nets or inadvertently captured by vessels fishing for other sea creatures.
The study sites were off the coasts of North Carolina, Northern Cyprus and Queensland in Australia, with turtles examined after they either died by stranding or being accidentally caught during fishing.
The highest concentration of microplastics was found in turtles from the Mediterranean but the study said the sample size didn't allow for explaining regional differences.
The most common microplastics were fibers, with possible sources being clothing, tires, cigarette filters and fishing nets, with the turtles possibly eating the plastics from contaminated prey throughout the food chain.
"From our work over the years we have found microplastic in nearly all the species of marine animals we have looked at; from tiny zooplankton at the base of the marine food web to fish larvae, dolphins and now turtles," said Penelope Lindeque, a scientist at the Plymouth Marine Laboratory.