The plastic polluting our oceans gets everywhere—including in the digestive tracts of every single sea turtle in a recent study. More than 100 turtles, across seven species and from three different oceans were studied, and microplastics were found in every single one of them.
“While this study has been successful, it does not feel like a success to have found microplastic in the gut of every single turtle we have investigated,” Penelope Lindeque, a molecular ecologist at the Plymouth Marine Laboratory and co-author of the study, said in a press release. “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.”
While the image of a sea turtle with a plastic straw lodged deep in its nostril is an enduring emblem of the impacts of plastic pollution, tiny particles of plastic are the more pervasive and insidious form of pollution in the ocean. So researchers decided to use an advanced method of digestion examination to look for microplastics in the guts of sea turtles around the globe, according to the study published in Global Change Biology.
The researchers collected digestive samples from 102 sea turtles and used a digital stereo microscope to look for bits of plastic smaller than five millimeters. They found more than 800 particles in total, with the majority of microplastics being fibers that come from broken down synthetic clothing, tires, cigarette filters, and ropes.
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While we know that larger pieces of plastic can cause a blockage in the digestive tracts of marine animals, the researchers noted the plastic they found is small enough that it should pass through the sea turtle’s system without issue.
But that doesn’t necessarily mean this pollution is harmless.
“The effect of these particles on turtles is unknown,” lead author Emily Duncan, an ecology research student at the University of Exeter, said in a press release. “Future work should focus on whether microplastics may be affecting aquatic organisms more subtly. For example, they may possibly carry contaminants, bacteria or viruses, or they may affect the turtle at a cellular or subcellular level.”
This article originally appeared on Motherboard.