ALICE LIPSCOMBE-SOUTHWELL

In October, The Ocean Cleanup’s system collected plastic from the Great Pacific Garbage Patch for the first time. But is this the best way of dealing with the plastic problem?

Science writer Alice reports on the latest plastic extraction technology that is attempting to clean up our waters. “It’s clear that we cannot continue living our lives as we always have done,” she says.

There was a time when many of us accepted a straw in our Friday-night cocktail without a second thought. But in October 2017, Blue Planet II hit our screens, opening eyes to the damage that plastic waste is causing to the world’s oceans. While conservationists and marine scientists had long been aware of the issue, it was this series that brought the problem hurtling into public consciousness. Since then, many of us have tried to restrict our use of single-use plastics, while governments have been urged to take action – in the UK alone, microbeads in toiletries have already been banned, and from spring 2020 plastic stirrers and straws will be restricted. Currently, around 350 million tonnes of plastic are produced each year – a large proportion of it single-use – and a whopping 12 million tonnes of the stuff enters our oceans, but following its movements is a tricky task. “There are definitely hotspots, such as gyres [see box, p34], but it is also predicted that a lot of plastic sinks. We are doing research at the moment, tracking litter’s movement,” says the University of Plymouth’s Imogen Napper, who studies plastic pollution in the marine environment.

Picking up the pieces

So what can be done to get plastics out of the ocean? One organisation that’s trying to tackle the problem is Netherlands-based The Ocean Cleanup, which was set up by inventor Boyan Slat in 2013, when he was just 18 years old. It wants to deploy its ‘passive systems’ into the five major ocean gyres, to collect plastic for recycling.

While its first system failed in December 2018, in October 2019 the organisation triumphed. After design tweaks and modifications, its latest device, called System 001/B, successfully captured and retained plastic debris from the infamous Great Pacific Garbage Patch in the North Pacific gyre. In a press release, The Ocean Cleanup claimed that its system even scooped out microplastics as small as 1mm. The organisation estimates that a fleet of its systems could clear half of the Great Pacific Garbage Patch in five years.

Despite its name, the Great Pacific Garbage Patch isn’t a huge floating landfill site that you could stroll across if the mood took you. Instead, it’s like a rather unpleasant minestrone soup – but in place of chunks of vegetables and pasta, the water is filled with assorted plastic waste, including ‘microplastics’ (smaller than 5mm). Plastic does not fully degrade like organic waste; instead, the action of the ocean and sunlight causes it to break down into tinier and tinier bits.

While it’s easy to understand how a plastic bag or piece of fishing line could

block the guts of a seabird or turtle if they mistook it for food, less is known about how microplastics affect the ocean ecosystems, and it’s currently an important area of research for scientists. The size of microplastics means they are small enough to make a tasty mouthful for the tiniest creatures, which potentially harms the organism and also means that the chemicals associated with the plastic will accumulate up the food-chain.

System 001/B may be successfully capturing plastics, but the University of North Carolina Ashville’s Rebecca Helm, who specialises in open-ocean ecosystems, says that it is catching many ‘neuston’ at the same time. The neuston is a group of organisms such as snails, sea slugs and plankton that live at, or just below, the ocean surface. Sometimes, these invertebrates occur in such enormous numbers that they’re like a living island. “It’s really the only ecosystem that exists firmly wedged between the atmosphere and the ocean,” says Helm. “It’s preyed upon by birds from above – there are a lot of seabirds that eat neuston – and also animals from below.”

This ecosystem is still poorly understood, and, according to Helm, there might not be any clear way that The Ocean Cleanup’s system could be adapted so it wouldn’t be impactful. “The reality is we don’t know if these animals are always mixed with the plastic or only some of the time,” she says.

As these animals are soft-bodied, buoyant and live near the surface, they cannot swim away or escape if they get stuck.

The Ocean Cleanup (which did not respond to requests for comment), states on its website that it has carried out extensive observation campaigns to understand how System 001 might interact with marine life, and that “no substantial interference with the ocean ecosystem were observed; nor did we observe any entanglement or entrapment of marine animals.” It also pledges to monitor presence of marine life before plastic is lifted out of the water.

Scratching the surface

Some experts wonder why The Ocean Cleanup is focusing its efforts on the ocean surface in the first place. A 2016 study by environmental consultancy Eunomia found that just 1 per cent of marine plastics are at

the ocean surface, while 94 per cent ends up on the seabed. In fact, plastics are almost ubiquitous and can be found locked within the ice at the poles, lurking in the deepest ocean trenches and scooped up by the handful at the seaside.

According to Laura Foster, head of clean seas at the Marine Conservation Society, we should be concentrating our efforts on reducing our production of plastics, rather than clearing up rubbish in the ocean. “One of the main issues with The Ocean Cleanup is that it supports big industry’s narrative that ocean plastic is a litter problem, rather than a production problem,” she says. “Cleaning up in the current situation has been compared to trying to deal with an overflowing bath with a teaspoon… the solution is found by turning off the taps!”

Napper agrees that we need to reduce our use of plastics, but also says that the best way to prevent plastic reaching the ocean is to stop it from land. “Land-based sources are the biggest contributor to plastic in the ocean,” she says. “We also need to identify the pathway from land into the ocean. We are currently researching major river systems to understand this movement.”

And The Ocean Cleanup has an answer for that. Back in October, the team launched the Interceptor, an autonomous system that collects plastic from rivers before it reaches the sea. So far, Interceptors have been set up in Jakarta (Indonesia), Klang (Malaysia) and Can Tho (Vietnam), while a fourth will soon be installed in the Dominican Republic. While estimates vary, experts agree that the vast majority – up to 95 per cent – of ocean plastic arrives via rivers. The Ocean Cleanup says just one Interceptor can scoop up 50,000kg of plastic per day, and the team has given itself the goal of installing the systems in 1,000 of the most polluting rivers by 2025. “I’m really happy The Ocean Cleanup is going in this direction, I think it’s much more productive,” says Helm.

Foster agrees that cleaning up the rivers is preferable to trying to extract plastics from the oceans, as it is easier to maintain and monitor a river-based system than one located at sea. Plus, river litter is more concentrated compared to in the oceans.

Experts agree that the vast majority of ocean plastic arrives via rivers.

“But again, we need to address why the material ends up in the river in the first place,” she says. “The

5p charge in the UK saw a huge reduction in the volume of plastic bags on beaches and in the marine environment. This sort of model must be emulated to further reduce plastic pollution.”

While it’s fantastic that wellmeaning people and companies are inspired to find ways to eliminate plastic from the environment, it’s clear that we cannot continue living our lives as we always have done, relying on other people to tidy up our mess for us. “We just need to use less,” says Thomas Stanton from the School of Geography at the University of Nottingham. “We also need better waste management facilities, to ensure that more plastic can be, and is, recycled.”

Once we’ve stopped plastic reaching our oceans, says Foster, the most efficient place to start cleaning up marine litter is on beaches. With everyone in the UK no more than 113km from the sea, that’s something we can all get on board with.

ALICE LIPS COMB ESOUTH WELL is production editor at BBC Science Focus.

The Ocean Cleanup’s system may collect plastic, but is it inadvertently trapping marine life, too?

The largest mass of ocean plastic can be found in the North Pacific.

Right: blue sea dragons, here seen with a Portuguese man of war, are part of the neuston. Bottom right: The Ocean Cleanup can collect tiny plastic pieces.

Is collecting plastic from our oceans enough?

Inventor Boyan Slat, CEO of The Ocean Cleanup.