At least 14m tonnes of plastic pieces less than 5mm wide are likely sitting at the bottom of the world’s oceans, according to an estimate based on new research. From a report: Analysis of ocean sediments from as deep as 3km suggests there could be more than 30 times as much plastic at the bottom of the world’s ocean than there is floating at the surface. Australia’s government science agency, CSIRO, gathered and analysed cores of the ocean floor taken at six remote sites about 300km off the country’s southern coast in the Great Australian Bight. Researchers looked at 51 samples and found that after excluding the weight of the water, each gram of sediment contained an average of 1.26 microplastic pieces. Microplastics are 5mm or less in diameter and are mostly the result of larger plastic items breaking apart into ever smaller pieces. Stemming the tide of plastic entering the world’s waterways and ocean has emerged as a major international challenge. Dr Denise Hardesty, a principal research scientist at CSIRO and a co-author of the research published in the journal Frontiers in Marine Science, told the Guardian that finding microplastic in such a remote location and at such depths “points to the ubiquity of plastics, no matter where you are in the world.” Read more of this story at Slashdot.