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More than 10 million tons of plastic waste enter the oceans each year. The floating of plastic debris in the sea has attracted public interest, due to the “Blue Planet Effect” in seeing movements to weaken the use of plastic straws and transport packages. However, such accumulations represent less than 1% of the plastic that enters the world’s oceans.
The 99% missing is believed to occur in the deep ocean, but until now, it was unclear where it ended.
Now, a new study by the University of Manchester (United Kingdom), the National Center for Oceanography (United Kingdom), the University of Bremen (Germany), IFREMER (France) and the University of Durham (United Kingdom) revealed the levels most significant microplastics ever recorded on the seafloor. , with up to 1.9 million pieces in a puffy layer that covers just 1 square meter.
The study has shown that deep water currents act as conveyor belts, transporting small fragments of plastic and fiber across the seabed.
These streams can concentrate microplastics within massive accumulations of sediment, which they called “microplastic hot spots.” These hot spots give the impression of being the remote oceanic reciprocals of the alleged rubbish patches formed by currents on the ocean surface.
The study’s lead author, Dr. Ian Kane of the University of Manchester, said: “Almost everyone has heard of the infamous floating plastic ocean” garbage patches, “but we were surprised by the high concentration of microplastics found on the sea floor.
“We discovered that microplastics are not evenly distributed in the study area; instead, they are distributed by powerful currents of the seabed that concentrate them in certain areas. “
The streams also carry water and oxygenated nutrients, which means that microplastic seafloor hot spots can also harbor essential ecosystems that can consume or absorb microplastics.
This study provides the first direct link between the behavior of these currents and seabed microplastic concentrations, and the findings will help predict the location of other critical points for microplastics in deep water and directly investigate the impact of microplastics on life. Marine.
Sediment samples were collected from the seabed of the Tyrrhenian Sea. The samples were then combined with calibrated models of deep ocean currents and detailed mapping of the seafloor.
In the laboratory, the microplastics were separated from the sediment, counted under the microscope, and further analyzed by infrared spectroscopy to determine the types of plastic. With this information, the team was able to show how ocean currents controlled the distribution of microplastics on the sea floor.
Dr. Mike Clare of the National Center for Oceanography, who was co-leader of the research, stated: “Our study has shown how detailed studies of seafloor currents can help us connect microplastic transport pathways in the deep sea and find ‘missing’ microplastics. The results highlight the need for policy interventions to limit flow. future of plastics in natural environments and minimize impacts on ocean ecosystems. “
Dr. Florian Pohl, Department of Earth Sciences, Durham University, said: “It is unfortunate, but plastic has become a new type of sediment particle, which is distributed across the seafloor along with sand, mud and nutrients. Therefore, sediment transport processes like bottom currents The marine particles will concentrate the plastic particles in certain places on the sea floor, as our research shows. “
Magazine reference:
- Ian A. Kane, microplastic hot spots on the sea floor controlled by deep-water circulation. DOI: 10.1126 / science.aba5899
