Out there, in the distant reaches of the ocean, currents collect tiny bits and bobs, pushing them together into a churning, deadly soup. Some of the materials gathered up are larger — toothbrushes, toys, tangled breakaway fishing nets. All of them are made of plastic.

Across the world's oceans it is estimated that there are at least seven distinct "garbage patches" where plastics sloughed from shore make their way to mingle.

Other types of refuse break down over time, or sink — leaden and waterlogged to the murky fathoms.

The garbage collects in the five subtropical gyres, where currents converge and pull together the collected waste that comes to span kilometres.

Sometimes the waste reaches down below the surface, in the water columns, making it impossible for marine life to avoid.

The flotsam rolls with the tides into shore, beating up the beaches of islands in their path, including the Galapagos, Hawaii and Easter Island. Fishing nets — made to last and sometimes lost at sea — will tear a beach apart as they break with the waves along the coast, their hard-wearing strands, pushed back and forth by the tides, eroding the shoreline.

What doesn't sink into the depths, where it may be consumed by fish and marine life, bobs along the top - where sea birds skim for food but often find instead that what they've ingested clogs their gullets and decays their stomach walls. When these unfortunate birds eventually waste away on shore, their rotten plumage is studded with the often brightly coloured, insoluble leftovers. Turtles too, will consume this plastic, as will pretty much every animal that comes across it in their search for food.

This is a recent phenomenon.

Since the 1950s, plastics have been finding their way to sea. Through direct dumping of waste into the ocean — a practice that has since been largely stopped — through people littering around water catchments; open storm water drains carrying refuse out to sea and natural disasters sweeping massive amounts of land-bound waste into the oceans. The plastic is what remains, because it is not broken down by the elements and it does not sink to the ocean floor.

Scientists at the fore of research into this problem estimate that the garbage accumulation has occurred predominately over the past 50 years, as our love of plastics has grown and grown.

Marcus Eriksen, the director of project development for the Algalita Marine Research Foundation, says the problem has affected more than 300 species of marine animals, with millions of individual animals suffering because of the plastics.

Artwork by Mandy Barker.

"This is across the board. It's sea birds, it's marine reptiles, it's marine mammals and a long list of fish that are consuming plastics," he says. "Plastics can float around the ocean picking up toxins… they are like toxic little pills that are then ingested."

The United Nations Environment Program produced an overview of marine litter in 2005. That report estimated that 6.4 million tonnes of litter were dumped in the ocean every year, and that 13,000 pieces of plastic litter float on "every square kilometre of ocean today".

That was seven years ago, and since then the problem has continued to grow. Eriksen estimates that the Japanese tsunami of March 2011 alone would have dumped a further 5 million to 20 million tonnes of refuse in the sea.

"We estimate that between 5 and 20 million tonnes of trash left the coastline of Japan… most of that is construction waste, so all the wood is gone by now. Wood doesn't last more than a year at sea, six months or less even.

"The only things left are going to be types of plastic… and anything that's trapping air. Which could range from light bulbs to cigarette lighters. I'm guessing with luck maybe a million tonnes or less of plastic," he says.

That much plastic piled together on land, says Eriksen, would be roughly the size of the largest Egyptian pyramid: "Imagine that being stuffed with plastic."

But that's from just one event. Overall, the size of the plastic pollution problem is much larger.

"The five subtropical gyres represent roughly 25 percent of the planet's surface — 40 per cent of the ocean, but 25 per cent of the total planet's surface.

"I've been to all five (gyres), and all of them are peppered with this confetti of broken-down, micro particles.

"So in less than 50 years we've covered a quarter of the planet in some of the remotest parts of the ocean with our trash. The fish that we harvest to feed the world are eating the fish that eat that trash," Eriksen says.

Artwork by Mandy Barker.

Based in California, Eriksen is about to embark on another trip into the plastic soup. The expedition will track the scale of the problem in the western North Pacific patch, which lies between Japan and Hawaii.

Once he has completed that trip, Eriksen will have visited all seven known conversion points — garbage patches — for the ocean's plastics. He says the problem is most severe in the northern hemisphere.

The UNEP report says marine litter poses a "dire, vast and growing threat to the marine and coastal environment.

"Every year the presence of marine litter causes damage that entails great economic costs and losses to people, property and livelihood, as well as poses risks to health and even lives. And marine litter spoils, fouls and destroys the beauty of the sea and the costal zone," it says.

Eriksen says one of the big problems with plastics is that their surfaces can trap toxins that then travel long distances, spreading throughout the ocean to be ingested by marine life far from the garbage patch itself.

Indeed, the problems are many. And the solution, while simple, is very complex to enforce. As Eriksen says, we need to stop putting plastics in the ocean. "We can fix it if we can stop adding more plastic. If we stop adding more plastic, what's out there now will wash ashore. It will take a while, but it will wash ashore," he says.

Eriksen says when people find out about the problem, they always want to help solve it. Raising awareness is a key goal of Five Gyres, the organisation he set up to map and combat the marine plastics problem.

UK-based artist Mandy Barker was working on a project where she planned to collect natural objects from along the shoreline when she noticed that there was a large amount of debris washing up. So she changed plans, and instead created works with the man-made items instead.

"There was more and more man-made debris amongst them. Combined with this I came across the image of an albatross chick carcass, the bird having died from ingesting plastics mistaken for food collected from the 'garbage patch', its stomach full of cigarette lighters and bottle tops. Following further research of how plastics affect marine life and ultimately end up in the human food chain, it was a subject I felt I could not turn away from," she says, in an email.

And so she created SOUP.

It's a stunning collection of photographic works based on items she gathered from beaches around the world, with one made up entirely of fragmented toy turtles washed up in a large group.

"I have had a huge response to SOUP from all over the world. Some people have commented that they haven't heard of the 'garbage patch' and how they didn't know such a problem existed. Others have been shocked by the diverse content of plastics found and have asked what can be done, setting up their own blogs and social networking sites in response," Barker says.

Plastics dominate the marine litter landscape, and land-based plastics are the majority of the rubbish floating around in the oceans, according to an article on the problem published in the Royal Society's scientific journal Philosophical Transactions B.

Recycling alone won't fix the problem, as only a fraction of produced plastics can be recycled, Eriksen says. He wants better regulation of the plastics industry, including rules restricting what kind of plastics can be produced for consumer products as well as regulation on the destruction of non-recyclable plastics.

Clean-ups of polluted oceans and coastlines, another part of Eriksen's approach, can be expensive. The UNEP report found that as far back as 1996, communities in the north sea region were spending about "USD6 million annually on cleaning their beaches in order to maintain their recreational values and keep them safe for beachgoers".

Artwork by Mandy Barker.

Artwork by Mandy Barker.

Artwork by Mandy Barker.

Artwork by Mandy Barker.

So solving the garbage patch problem is not only expensive but also a logistically difficult operation that would involve a combination of clean-up, regulation and upgrade work to reduce the amount of plastics in our oceans.

Still, Eriksen is upbeat that there will be a way to co-ordinate the clean-up and ensure better marine health in the future. And that largely the solution will come through public education, legislative control and action by manufacturers to create less nonrecyclable waste.

"It has all got to happen simultaneously for it to work. I'm an optimist. I give a lot of presentations where everyone I talk to responds with: 'What can I do, how can I help?'" he says.

"Plastic has a place in society [but] we need industry coordination in all of this… Recycling yes, but containment has to happen to stop plastics entering our storm water drains and then our oceans. We need to improve waste collection, have more bin collection and more bins out there to collect trash. Instead of landfill, we need to look to some very efficient waste energy systems."

For example, plastics can be incinerated at high temperatures to create energy that can be used for electricity production, Eriksen says.

Plastics are here to stay, but how we dispose of what we use, and regulate what is produced, will determine how invasive we allow them to become.