Public Release: 

Giant larvaceans transfer ocean pollution by ingesting plastic waste

American Association for the Advancement of Science

Pinkie-sized plankton called giant larvaceans can ingest tiny pieces of plastic and pass them in their fecal pellets, which then sink to the bottom of the ocean. This finding suggests larvaceans and other filter feeders may contribute to the more rapid transfer of plastic pollution from the surface to the sea floor. Of all plastic pollution, microplastics have one of the strongest impacts on marine ecosystems, since they are small enough for animals to easily eat. Giant larvaceans filter ocean water particles from inside of "mucus houses" - 3-foot-wide structures that they build and live within. Kakani Katija and colleagues say these plankton are the ideal candidates to investigate microplastic ingestion, because their feeding filters exclude particles of the same size range as microplastics. The scientists studied how larvaceans in Monterey Bay, California consumed pieces of plastic smaller than a grain of sand. They introduced microplastics into the ocean via a remotely operated vehicle and evaluated if the larvaceans consumed the particles. The researchers observed the majority of the larvaceans ingested the microplastics. Microplastics also stuck to the larvaceans' gooey houses, which sink to the seafloor after the filter-feeders discard them. Katija et al. note that larvaceans likely aren't gobbling up much plastic in the ocean (at least for now), as most microplastics float closer to the ocean surface than larvaceans are typically found. To better understand the overall impacts of microplastics on marine food webs, the authors argue that additional investigation is needed to further explore plastic concentrations throughout the ocean, and how animals eat them.

