2 April 2020
There may be twice as many microplastics in the ocean than previously thought. There could be more than 3700 microplastics in one cubic meter of seawater. These and other findings were made by using nets with different mesh sizes and comparing the results. The research was carried out at two English universities and was recently published in the scientific journal Environmental Pollution.
MESHES IN THE NET
Measuring the number of microplastics on the surface of the sea is done by hanging finely meshed nets behind a sailing boat. Over time, these are brought in, and the number of microplastics caught is counted. Nets with a mesh size of 333 μm (0.333 mm) or 500 μm (0.5 mm) are used for this purpose. If the mesh size is even smaller, the holes easily get clogged with organic material. However, the researchers also succeeded in measuring with a finer mesh net, one of 100 μm (0.1 mm).
This is the first study in which these three types of nets were used simultaneously. Microplastics were fished in the coastal waters of both England and the United States. Coastal waters are also home to most marine life. Most microplastics were found to be fibers: in the U.S. 84% and in England 77% of the total.
The measurements indicate a substantial underestimation of the number of smallest microplastics in the ocean. For example, the concentration of microplastics with a 100 μm mesh size net was ten times greater than with a 500 μm mesh size net. And 2.5 times the size of a 333 μm net. The number of microplastics in the oceans has so far been estimated at between 5 and 50 trillion particles. Based on the new findings, the English researchers estimate this number to be much higher: between 12.5 and 125 trillion.
ZOOPLANKTON ingests MICROPLASTICS
Captain Charles Moore was one of the first to warn the world about the consequences of the plastic soup. In one of the seawater samples he took in 1999, he counted more pieces of plastic than plankton at the time. His conclusion about the increasing number of microplastics in the sea was prophetic: “The ingestion of plastic by planktivores (organisms that feed on plankton) will increase. Plastic will enter further and further into the food chain.”
Researcher Penelope Lindeque of the Plymouth Marine Laboratory says: “We find 3700 microplastics in one cubic meter of seawater, much more than the number of zooplankton in the same quantity. (…)’. It’s the very smallest microplastics that make it easy to ingest plankton. A better understanding of the amount of microplastics in our seas and a more detailed description of the types of microplastics helps to determine the risk they pose to marine animals and ecosystems.” As early as 2015, she explained in a video that microplastics pose the greatest risk to marine life because plankton ingests them. Another researcher recorded on film the moment that plankton ingests a microfibre.
Meanwhile, the contamination with microplastics continues. They come from synthetic clothing, car tires, or they are used in cosmetics. Plastic waste in the environment is also falling apart into smaller and smaller pieces.
You might also like