'It's a way of the sea returning the trash to us': Why plastic-filled 'Neptune balls' are washing up on beaches

(Image credit: Getty Images)

As tiny pieces of plastic clog our oceans, natural meadows of seagrass are bundling up microplastics and spitting them back out onto beaches in the form of "Neptune balls".

Neptune balls, or Posidonia oceanica, are round, compact bundles of seagrass mostly found in the Mediterranean Sea. For centuries, Posidonia has been used for packaging, bedding and even insulation for houses. But researchers from the University of Barcelona have found these spongy balls are spontaneously performing another function: mopping up ocean plastic from the seafloor.

In the ocean, microplastics – particles under 5mm in size – often originate from items such as plastic bags, bottles and fishing nets. These plastic fragments can harm our health, affecting everything from bone and brain function to hormones (read more about how microplastics affect our health).

Although most plastic pollution originates on land, the ocean – including seagrass meadows – acts as a sink.

More:
https://www.bbc.co.uk/future/article/20250901-why-plastic-filled-neptune-balls-are-washing-up-on-beaches