Scientists draw the most complete map of marine litter pollution in the Mediterranean Sea

It seemed impossible with the technology available until now, but the combination of Earth observation satellites, supercomputers and advanced algorithms has allowed an international team of scientists to map the map of pollution by marine litter in the Mediterranean most complete to date.

Scientists of the Cadiz University (southern Spain), Superior Council of Scientific Investigations (CSIC) Spanish, of the European Space Agency (ESA), numerous multinationals in the space sector and universities and research centers in several countries have located the garbage trails that flood the Mediterranean and have also pointed out that the incorporation in observation satellites of a sensor specifically designed for this purpose It would multiply by twenty the current capacity to detect this contamination.

The work, whose conclusions appear this Friday published in the journal Nature Communications, suggests that this sensor would allow the identification of floating objects one meter in size, which would be especially relevant not only to detect floating garbage, but also to discover pressure losses. on ships, oil spills or for search and rescue tasks at sea.

The research, coordinated by Andrés Cózar (University of Cádiz) and Manuel Arias (CSIC Institute of Marine Sciences), has been funded by ESA, the Ministry of Science and the EU, and has been completed with a demonstration of its applicability with real cases.

Thus, they have evaluated the effectiveness of action plans against garbage in the Tiber River as it passes through Rome (Italy), they have identified pollution sources related to maritime transport through the Suez Canal (Egypt), and they have used satellite observations to guide cleanup tasks in the waters of the Bay of Biscay (Spain).

What has never been seen from space

“We have observed the never seen; something that traditional field sampling carried out to locate floating garbage in the sea will never be able to compete with.”he told EFE Andrés Cozarand valued that they have achieved it with a technology that was not specifically designed for this purpose, so the possibilities that a specific sensor would offer will be even greater.

The researcher announced that the next step will be to design and test a prototype to demonstrate the effectiveness of this device before the ESA – which has financed the project – decides to incorporate it into an Earth observation satellite in an upcoming launch, and assured that Other space agencies, including NASA and the Japanese JAXA, have also been interested in this work and in the future a joint mission could come to fruition.

The amount of plastic on the sea surface is rarely high enough to generate a detectable signal from space, and plastic and other floating debris needs to aggregate into dense patches at least a dozen meters in size to that current satellites can detect them.

These garbage patches (trails) are usually filament-shaped, and arise as a result of marine currents on the surface, the researchers have observed, and they have specified that the detection of these trails reveals a very high contamination in a place and at a time. concrete.

Researchers have now verified the usefulness of these streams, even the smallest ones, as indicators of marine litter in the Mediterranean, and based on a six-year historical series of satellite images they scoured the sea in search of remains of trash each year. three days and at a spatial resolution of 10 meters.

Garbage in the sea; a needle in a haystack

They analyzed some 300,000 images provided by the EU Copernicus Program satellites, whose sensors, although not specifically designed for the detection of garbage, have demonstrated a certain capacity for detecting plastic.

“Looking for meter-sized aggregations of garbage on the ocean surface is like looking for needles in a haystack,” the researcher explained Manuel Arias.

The researchers managed to locate thousands of trash trails, many of them more than a kilometer in length and some up to 20 kilometers long, enough to create the most complete map of marine litter pollution in the Mediterranean to date.

Andrés Cózar explained that they have scrutinized the data provided by the Sentinel satellites of the ESA Copernicus program and have focused the “search” in the Mediterranean, but that the procedure can be replicated practically throughout the planet.

Numerous previous studies had already demonstrated this, but researchers corroborate it again. “Yes, there is a lot of garbage in the sea”stated Cózar, and warned that what the satellites detect is “only” what floats in the oceans, but that a large part of the waste ends up on the coast or submerged in the ocean, so its early detection is especially important. to proceed with its elimination and mitigate the most harmful effects.

The possibility of detecting this waste before it sinks would allow cleaning tasks to be undertaken that are much more targeted in time and space.explained the researcher, and also pointed out the possibility that this system offers to locate the sources from which these “injections” of garbage come, so its findings and technological developments would serve, in addition to locating and removing floating garbage, to reinforce pollution surveillance and control tasks.