Plastic particles are few and far between
The researchers found between 25 and 100 microplastic particles per cubic metre of water collected. In the samples with the highest measured concentration, this corresponds to one plastic particle per 10 litres of water. By contrast, the samples contained about 100,000 times more plankton than microplastics.
In total, 88 per cent of the microplastic particles captured by the fine-meshed nets are so small that they would escape the conventional Manta nets. According to PhD student Gunaalan Kuddithamby, not many studies have used this method—both because it is difficult to collect the samples and because it is expensive and time-consuming to analyse them.
DTU Aqua have conducted several studies that examined the smallest fraction of microplastic. These studies were collected in the waters around Greenland, and on an expedition from Denmark to the Caribbean that sailed through the ‘North Atlantic Garbage Patch’. Here, too, the researchers found smaller amounts of microplastics than they expected. Even the samples with the highest concentrations contained less than one plastic particle per litre of water.
As the presence of microplastics in the oceans will increase, partly because plastic waste there breaks down into much smaller pieces, Gunaalan Kuddithamby stresses the importance of repeating the measurements with these more precise methods to follow the development.