Comprehensive coverage

When the seabed is covered with plastic

Plastic continues to dominate every good plot: new research reveals that the amount of microscopic plastic on the ocean floor has tripled in just 20 years. Moreover, the microplastic at the bottom of the sea almost did not crumble or break down even after decades

The plastic that reaches the bottom remains available to the animals in the sea. Photo by PublicDomainPictures on Pixabay
The plastic that reaches the bottom remains available to the animals in the sea. Photo by PublicDomainPictures on Pixabay

At the end of the second season of the supernatural drama series "Manifest", one of the wings of a plane was plucked from the ocean - this despite the fact that it had landed in New York not long ago completely intact, and then completely caught fire before the eyes of the heroes of the series. Unlike the wings of mysterious planes, a different kind of debris arrives אל the oceans on a daily basis and no longer surprises anyone - the tiny plastic particles called "microplastic". in research New של Scientists from Catalonia and Denmark The remains of the microplastics that sank to the bottom of the sea were examined, and it was discovered that the amount of plastic particles on the bottom tripled in only about 20 years.

Microplastics are microscopic particles of plastic that come from plastic products that have worn out and broken down over time and with the effects of the sun and water, as well as plastic parts that have been deliberately produced in microscopic sizes for different uses (like the plastic balls that are added to cosmetic products). These particles cause long-term damage to marine animals, which may eat them due to the similarity between them and their natural food, which may result in blocking the absorption of nutrients in their bodies and damage to their digestive system. The microplastics may also harm the animals due to the harmful substances found in the plastic (eg bisphenol A וphthalates) and due to toxic organic compounds (Persistent organic pollutants) attached to it. Beyond that, the plastic particles may also reach many other animals through the food web.

In recent years, more and more evidence has accumulated that microplastics are also getting inside the food And our drinking water - even to our blood, to the human placenta וfor breast milk, And that they are Are liable Nose harm for our health.

Plastic is forever

The new study, recently published in the scientific journal Environmental Science & Technology, does not require deciphering messages and visions like those revealed to the protagonists of "Manifesto", but that does not mean that it was simple to do. Dr. Noam van der Hal, chief scientist at Midan Technologies and a lecturer at Tel Hai College, explains that the researchers collected samples from the sea - a process that is more complex than collecting them from the ground. "Humans cannot reach such depths, so researchers use pipes, small bulldozers or special robots for this purpose," he says.

The amount of plastic particles on the ocean floor has tripled in just 20 years

In the case of the new study, the collection took place in the western part of the Mediterranean Sea, in the region of Tarragona in Catalonia. It is about the Dalta - an area where the alluvium of a river spills into the sea, where various sediments accumulate. The area was chosen for the study for two reasons: first of all, rivers bring a lot of sediments to the ocean (sediments, various solid materials that disintegrate and move with the water from place to place), therefore river estuaries have a higher amount of sediment than can be found in the open ocean. Secondly, there are often populated areas near the rivers, so there is a high chance of finding various pollutants in the rivers - including microplastics.

According to the researchers, according to the research findings, since the 80s of the 20th century, and especially since 2000, there has been a significant increase in the rate of accumulation of polyethylene and polypropylene particles (common types of plastic) that came from packages, bottles and cling film, as well as polyester, massive plastics synthetic clothing. According to them, these three substances together added up to 1.5 milligrams for every kilogram of sediment collected.

Another important finding that came up in the research was that from the moment the plastic remains were trapped in the bottom, they hardly underwent weathering - that is, they did not break down or disintegrate - for decades. Beyond that, the researchers recognized that the microplastics created in the 60s almost did not degrade, because they were embedded in the sediments. "This may indicate that it takes plastic even more time to break down than we thought so far," Van der Hal explains.

Beyond that, the researchers discovered that the increase in the amount of plastic in the soil from year to year, from 1965 to 2016 - corresponds to the increase in global plastic production.

The "Bermuda Triangle" of plastic?

If there are microplastics in so many unwanted places, why was it important for scientists to study specifically what is happening at the bottom of the sea? First of all, because the damage of the microplastic does not end when it sinks. "The plastic that reaches the bottom remains available to the animals in the sea: it is possible, for example, that a dolphin will rub its mouth on the bottom to find fish, thus ingesting microplastic particles - and with them, also the various chemical substances and pollutants that have accumulated on them," says van der Hal. "Alternatively, there are types of microplastics that are lighter than water - but on which layers of different substances accumulate, such as algae, bacteria and dirt, and thus they become heavier than water and sink to the bottom. It is possible that these layers will disappear, for example due to friction or being eaten by plankton (marine creatures that drift with the current of water - NS) - and then the plastic will return to floating in the sea."

But there is another reason why the study of microplastics on the seabed - and its quantities - may be important. Van der Hal says that today, the amount of plastic waste that is known to flow into the sea does not match the amount of microplastic found in the sea in studies. "It's a very big question in this field - where does all the plastic go?" He says. "If you check the amounts and types of plastic that have sunk into the sea, you can try to solve this mystery - and the bottom is a good place to look, because many particles are collected there." It should be noted that in addition to microplastic, heavier plastic is also collected at the bottom - such as the plastic from which bottles are made, or PVC that is used in the building sector.

exercise judgment before consumption

It is possible that the responsibility for the appearance of the airplane wing from "manifest" in the ocean lies with supernatural forces - but in the case of the microplastic, it is quite clear that we, humans, are solely responsible for the phenomenon. What can be done, then, to reduce the continued accumulation of unnecessary microplastics at the bottom of the oceans?

Van der Hal recommends exercising judgment before each purchase or use of plastic, and asking ourselves - do we really need this plastic? Is it possible to avoid using it, and thus reduce, even slightly, our consumption? Such "unnecessary" plastic can include both "classic" products, such as disposable utensils and supermarket bags, and clothing that includes plastic materials, such as polyester, brass and nylon clothing, which produce large amounts of plastic waste due to their fibrous structure. "When we manage to avoid using plastic that has no purpose - we are already doing a lot", he concludes.

More of the topic in Hayadan:

Skip to content