TECH

How is the 'giant serpent' that scientists want to use to clean the oceans

When Dutch teen Boyan Slat entered the sea in Greece seven years ago, he was surprised to see more plastic than fish in the water. He was so annoyed by the pollution that he began campaigning to clean the oceans.For a long time, few people took him seriously. He was just a college boy with an idea in his head. An idea that, at first glance, looked like shit.But on Saturday, with the backing of big investors and an ambitious engineering job, Slat was able to launch a huge plastic snake-like collection system. The device left the San Francisco Bay bound for the large Pacific "garbage island" - which is located between California and Hawaii.So far the focus of plastic collection campaigns has been on the beaches and consists basically of gathering volunteers around the world to collect plastic bags and bottles from the coast.But there are few initiatives to try to clean the oceans from the inside.Some experts are skeptical of Slat's initiative. And despite the tests and digital simulations, no one knows for sure if the "snake" will work.On the one hand, some think that it could be a distraction to the most eminent problem: the dumping of plastic into the sea. On the other hand, there is concern that the operation could cause serious damage to marine life.But Boyan Slat and his staff at the nonprofit The Ocean Cleanup are convinced that the sheer amount of plastic in the oceans requires immediate action.

What's the point?
The objective of the Slat team is to reach the eastern Pacific, especially the island of dirt, where circular marine currents have concentrated a large amount of plastic in a single area.The goal is to halve the contamination of this area every five years, so that by 2040 all the garbage has disappeared."We are in a hurry," said Lonneke Holierhoek, the project's head of operations in Rotterdam, the Netherlands.The Dutch government is a major sponsor, along with some well-heeled companies and investors. The project, estimated at at least $ 20 million ($ 80 million), is no longer an idea of ​​a young man to become an international initiative.In the project office, the smell of algae and garbage is strong. On the tables and on the floor there are boxes full of plastic fragments, brought from the sea in previous expeditions and that represent a reminder of the task that those involved in the undertaking have to face."If we do not do this," says Holierhoek, "all this plastic will begin to break down into smaller and smaller pieces, and the smaller the parts, the more harmful they will be and the harder it will be to extract them from the marine environment."
Holierhoek is an engineer who has spent the last two decades devoting herself to projects far from the coast. She is not an activist, but someone with a great deal of experience working with enormous structures at sea.

For her, the snake project is a legitimate effort to try to reverse the tide of contamination. "More than talking about the problem or protesting, it's about trying to solve it," says the engineer.

How it works?
The main element of the "snake project" is the collection system, which is passive. That means there are no mechanisms or machines. Instead, it was designed to gently move and pick up any plastic in its path.The machine is shaped like a giant snake and is made up of sections of tubes. It measures 600 meters in length and floats in a "U" shape. Underneath it carries a three-meter screen.The goal is for the collection system to capture plastics to form a dense mass. The fish should be able to swim under it and, as the appliance has smooth surfaces, the hope is that no species will suffer damage.The system takes cameras on board, whose function is to monitor the operation. Approximately every six weeks, a ship will travel to the "snake" to collect all the collected plastic and take it to the mainland, where it will be recycled.

All recovered material must be transformed into products to be marketed with the seal "made from marine plastic". They will be sold at a higher price.

What are the potential problems?
Some experts heard by BBC News fear that marine life will suffer damages.Anything thrown into the sea covers algae quickly, attracting plankton which in turn attracts small fish and then larger fish.That is why, for example, industrial fishing fleets install "fish aggregation devices" to play the role of bait.But Lonneke Holierhoek has an answer to those questions. She states that an independent environmental study has found that this impact can be minimized, for example, by generating a noise just before the plastic is collected in order to chase away the fish.But Sue Kinsey of the Society for Marine Conservation is one of those who is not convinced that the snake project will help solve the problem of pollution without causing harm.She says admire the passion and willpower of those involved with the project, but sees it "The main problem is the creatures that float passively in the ocean and can not get out of the way: once they are in this field, they will be trapped without being able to move," he says.It also ensures that in terms of cost it is more effective to clean the beaches and focus on preventing more plastics from reaching the oceans.Professor Richard Lampitt of the UK's National Center for Oceanography also praises the project but acknowledges that much of the plastic that is going to stop at sea sinks relatively fast, so the effort would not make a big difference.

Lampitt also highlights the effects on the environment for the construction and execution of the snake project, which provides for the construction of 60 collection devices and the transportation of boats on their round trip, all to recover approximately 8 thousand tons of plastic a year.

"The cost benefit ratio is not at all advantageous," says the professor.However, one of the project's researchers, Laurent Lebreton, says the effort is worth it. He argues that human waste has a negative impact on the natural world.

Lebreton shows how a small piece of white coral grew around the fibers of an old fishing net and how on the uneven edge of a plastic bottle there are unmistakable marks of teeth left by the bite of a fish.
"Fish swallow this plastic and those same fish end up on our plate later, plastic has become part of the food chain," says Lebreton.
"There is a solution: you first have to make sure the plastic does not go into the natural environment, and then you have to collect everything that we have accumulated since the 1950s," he adds.
The collection system will take three weeks to reach the waste island, located about 2,000 kilometers off the coast of California.

Still this year, the first results of how the first snake project is working, which aims to clean the oceans from the inside, should be available.


Source:bbc.com and mundophone