For years, plastics have made up a large portion of the debris polluting the marine environment. Much of this plastic consists of particles under 5mm in any dimension. Writing in Frontiers in Marine Science, an international team of researchers from the UK and Norway examined the occurrence and abundance of microplastics in UK seafloor sediments between 2013 and 2021. The scientists used a fast-screening approach for the detection and quantification of microplastics in sediment samples.
https://blog.frontiersin.org/2023/02/16/microplastic-waste-large-ancient-squirrels-malaria-gut-microbiome-play-juvenile-rats-podcast-listening/