Microplastics in the ocean may prevent the storage of carbon dioxide on the seafloor and disrupt one of the Earth’s most important natural processes, an Irish study has found.

Researchers from NUI Galway examined the effect that the particles have on salps, small jellyfish-like animals. Salps play an important role in reducing the effects of carbon dioxide on Earth by ingesting algae at the sea’s surface, which contain carbon dioxide (CO 2 ) taken in during photosynthesis.

Once they consume the algae, the salps produce dense “faecal pellets”, which rapidly sink to the deep sea and carry the captured carbon with them.

Microplastics are fragments of larger pieces of plastic that have been broken down in the sea. Most have low densities and float on