For centuries, folks along the Mediterranean Sea have called the little bundles of Posidonia oceanica seagrass \u201cNeptune balls,\u201d a reference to the Roman god of the sea. Never would they have imagined, though, just how modern the balls have become\u2014filling with microplastics<\/a>. Now, the underwater sea meadows that produce these Neptune balls acts as a sort of sink, washing the waters of roughly 900 million plastic fragments annually. <\/p>\n Related Story<\/p>\n For millennia, Posidonia oceanica have served a useful purpose for humans<\/a>\u2014the Neptune balls are anti-bacterial and anti-fungal<\/a>, and have been used as building insulation and in various commercial applications\u2014but the value of Neptune balls continues to grow. According to a 2021 study published<\/a> in the journal Nature, seagrass has become invaluable as a natural filter, washing our water of plastics. \u201cThere is strong evidence that the seafloor constitutes a final sink for plastics from land sources,\u201d the study\u2019s authors wrote. \u201cThere is also evidence that part of the plastics lying on the shallow seafloor are washed up back to the shoreline.\u201d Seagrass meadows trap plastic<\/a> debris with the plant\u2019s natural lignocellulosic fibers, which are then ejected from the plant and wash up on shores as balls, helping to \u201ccounteract marine plastic pollution.\u201d<\/p>\n Posidonia oceanica creates an underwater meadow that can grow on rocky or sandy bottoms, and helps clean water<\/a> more than 130 feet below the water\u2019s surface. The plant\u2019s creeping rhizomes create a root structure, and it forms shoots all year round. These structures grab pollutants\u2014typically from river water as it flows into the Mediterranean\u2014and traps them. Then, the shoots break away from the plant and form balls that find their way to shore, bringing with them whatever they grabbed. Related Story<\/p>\n The study specifically investigated balls of seagrass found on Mallorca, Spain. While only 17 percent of the Neptune balls contained microplastics, the ones that did collect it had it in dense quantities (tighter balls were more likely to have grabbed plastic). \u201cAfter our paper was published,\u201d Anna Sanchez-Vidal, lead author of the Barcelona-based study, told<\/a> the BBC, \u201ca lot of people started sending me [pictures of] monster Neptune balls. Sometimes they had sanitary towels, tampons, wet wipes\u2014things with a lot of cellulose<\/a>, so they sink.\u201d <\/p>\n The study found that up to 1,470 plastic items per kilogram of plant material were trapped in Neptune balls. But plastic isn\u2019t the only thing snatched by the plant\u2014it\u2019s known to harbor carbon<\/a> too, trapping pollutants and locking them away from the atmosphere.<\/p>\n
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