"SARONIC GULF, Greece - Overtourism and heavy maritime traffic across the Mediterranean are contributing to a rise in pollution in Greece's azure waters, say Greek scientists who have deployed thousands of mussels on the seafloor to help detect microplastics.

Mussels, filter-feeding organisms that absorb a range of contaminants into their tissue, including invisible microplastics, have been used globally for decades as a barometer of marine pollution.

Researchers at the Hellenic Centre for Marine Research (HCMR) have been using them in Greece, whose pristine beaches and limpid seas lure millions of tourists annually.

In May, they submerged cages with mussels at various depths and locations across Greece, from busy ports to remote islands. They retrieved them in September to analyse the particles the mussels had accumulated. To test surface water they use a floating net device."

Stelios Misinas reports for Reuters November 3, 2025. [2]