Photo by Jennifer Lavers.

There are only about six hundred inhabitants on the remote Cocos (Keeling) Islands in the Indian Ocean, but researchers have found a massive amount of plastic debris washed up on the beaches. They estimate that most of the debris on the atolls is buried under the sand and is micro-debris that is extremely dangerous for wildlife.

The researchers estimate that, on the two atolls, which comprise 27 tiny islands, there are more than 414 million pieces of plastic debris, largely comprising single-use, everyday consumer items. And the scientists say their findings are bound to be an underestimate.

The team estimates that the total debris on the Cocos islands, which are an Australian territory, weighs about 238 tonnes¹.

In their report, which was published in the journal “Scientific Reports”, the researchers say they estimate that the debris includes about 373,000 toothbrushes and 977,000 shoes (mostly flip-flops).

This is more waste than the islands’ community would produce in about 4,000 years.

“Cocos is literally drowning in plastic, which is really sad considering how incredibly remote these islands are,” said the report’s lead author, Jennifer Lavers, an eco-toxicologist from the Institute of Marine and Antarctic Studies at the University of Tasmania in Australia.

Photo credit: Silke Stuckenbrock.

Of the identifiable items of debris, nearly 25 percent were classified as disposable plastics such as straws, food packaging, bottles, cutlery, and bags.

The researchers were particularly surprised at how much buried debris they found. They estimate that 93 percent of the debris on the Cocos islands is buried up to 10 centimetres below the surface and about 60 percent of this buried plastic is micro-debris that measures between two and five millimetres.

Based on the estimated totals, the quantity of debris predicted to be buried up to 10 centimetres below the beach surface is 26 times greater than the amount of debris visible on the beach surface.

Micro-plastics on the beach of South Island. Photo credit: Cara Ratajczak.

“Removing the significant quantities of plastic already in the ocean is not possible, making the prevention of new items entering the ocean at their source critically important,” the researchers say in their report.

Lavers previously made headlines around the world when, in May 2017, she revealed that beaches on the remote Henderson Island in the South Pacific had the highest density of plastic debris reported anywhere on Earth.

While the density of plastic debris on Cocos (Keeling) Islands beaches is lower than on Henderson Island, the total volume dwarfs the 38 million pieces weighing 17 tonnes found on the Pacific island.

Debris found on the Cocos (Keeling) Islands.

Lavers says that remote islands that don’t have large human populations depositing rubbish nearby are an indicator of the amount of plastic debris circulating in the world’s oceans.

“Islands such as these are like canaries in a coal mine and it’s increasingly urgent that we act on the warnings they are giving us,” she said.

“Plastic pollution is now ubiquitous in our oceans, and remote islands are an ideal place to get an objective view of the volume of plastic debris now circling the globe.

According to the United Nations Environment Programme, an estimated 7.2 million tonnes (about 8 million tons) of plastic waste enter the world’s oceans each year.

Research has shown that nearly 60 percent of seabird species have ingested plastic and it is predicted that, by 2050, the percentage will reach 99 percent.

Birds mistake the brightly coloured items for food, or swallow them by accident, and this causes gut impaction, weight loss and sometimes even death.

Lavers says that the researchers’ estimate of 414 million pieces weighing 238 tonnes on Cocos (Keeling) is conservative as the scientists only sampled down to a depth of 10 centimetres and couldn’t access some beaches that are known debris “hotspots”.

She says there are still plenty of pristine, quintessential, tropical beaches free from plastic on the Cocos islands, but beaches that face into the predominant currents are accumulating incredible amounts of debris.

Arrows indicate the direction of major oceanic currents,
including part of the Indian Ocean Gyre.

The researchers say their findings suggest that global debris surveys, most of of which are focused solely on surface debris, have drastically underestimated the scale of debris accumulation.

The research team studied seven of the Cocos islands. They marked off transects on beaches, then multiplied the mean density of items recorded from those transects by the total beach area to estimate the total debris visible on the beach surface of each island. They did separate calculations for the buried debris and the debris in zones of “beach-back vegetation”.

The scientists explain that anthropogenic debris (debris dumped by humans) harms a diversity of aquatic wildlife directly via entanglement and ingestion, and indirectly through exposure to plastic-associated chemicals and microbes.

Photo supplied by Jennifer Lavers.

“There is an urgent need to quantify and mitigate these impacts, establish patterns of temporal change, and recognise plastic debris for what it is: a persistent, hazardous, and rapidly expanding environmental pollutant,” the researchers state.

Photo credit: Silke Stuckenbrock.

One of the report’s co-authors, Annett Finger from Victoria University, says the global production of plastic is continuing to increase. Nearly half of the 8,300 million tonnes of plastic produced over the past sixty years was manufactured in the past 13 years, she says.

“An estimated 12.7 million tonnes of plastic entered our oceans in 2010 alone, with around 40 per cent of plastics entering the waste stream in the same year they’re produced,” Finger said.

“As a result of the growth in single-use consumer plastics, it’s estimated there are now 5.25 trillion pieces of ocean plastic debris.

This estimate suggests that there are now more pieces of plastic in the ocean than there are stars in the Milky Way.

“Plastic pollution is a well-documented threat to wildlife and its potential impact on humans is a growing area of medical research,” Finger said.

“The scale of the problem means cleaning up our oceans is currently not possible, and cleaning beaches once they are polluted with plastic is time-consuming, costly, and needs to be regularly repeated as thousands of new pieces of plastic wash up each day.”

The only viable solution, Finger says, is to reduce plastic production and consumption while improving waste management to stop the debris entering oceans in the first place.

The researchers say that, unless drastic steps are taken, the numbers and challenges will only grow, with the quantity of waste entering the ocean predicted to increase tenfold by 2025.

“Once in the ocean, plastic items exposed to wave action and sunlight begin to fragment into small particles that persist for decades, perhaps centuries,” the researchers add.

Therefore, they say, the characteristics that make plastic such a popular material (e.g. its durability, light weight, and low cost) also contribute to its abundance in the ocean, and to its role as a significant environmental threat.

Lavers and her colleagues say that, because there are few local sources of pollution and little human interference (no recreational beach users or debris removal via beach clean-ups), isolated islands with little or no human occupation can act as marine pollution monitors, providing unique insights into debris accumulation trends.

They say that their findings highlight a growing need for the development of effective policies and mitigation, both of which are currently focused primarily on localised clean-up of visible debris.

The findings also raise questions about the potential impact of buried plastic on sea turtles, crustaceans, meiofauna, and other wildlife nesting or living in beach sediments, the researchers say.

“Furthermore, the removal of buried debris would require major mechanical disturbance of sediments, with potentially significant environmental impacts on inhabiting biota.”

The removal of micro-debris from beaches poses a significant challenge even on a small scale because of the time required to separate plastics less than five millimetres in size from sediment and other organic materials, the researchers add.

As a result, large-scale estimates of debris accumulation generated by researchers and citizen scientists rarely account for micro-debris items, meaning the data commonly referenced by media and policy makers are very conservative, they say.

Lavers urges people to think how they can help by removing at least one plastic item from their day-to-day activities. “If it’s a plastic toothbrush that you use every morning … maybe think about switching to bamboo.”

Jennifer Lavers surveys some of the plastic debris on the Cocos islands. Photo credit: Silke Stuckenbrock.

Fishing-related debris is relatively uncommon on the Cocos islands (it made up just 1.6 percent of the items recorded). On other remote islands, 8–46 percent of items washed up on beaches are fishing related.

“The debris on CKI seems to mirror global data on plastic production, and highlights a worrying trend in the production and discharge of single-use products,” the researchers state in their report.

The situation on the Cocos (Keeling) Islands is not unique, the researchers point out. The presence of significant quantities of debris has been documented on islands and coastal areas from the Arctic to the Antarctic

“Together, these islands and coastal areas reflect the acute symptoms of an otherwise rapidly increasing environmental hazard,” the researchers say in their report. Legal protection and a lack of human activity has not afforded remote sites like the Cocos (Keeling) Islands and Henderson Island protection from debris washing up on their shores, they say.

“On CKI, infrastructure (e.g. waste management) has also failed to protect these islands against debris accumulation. So, what will provide effective protection? With the quantity of debris entering the world’s oceans predicted to increase by an order of magnitude by 2025, that question is now urgent.”

Anthropogenic debris is widespread on remote, uninhabited islands. A: Aldabra Atoll, northwest Indian Ocean, 2017. B: Holandes Cays, San Blas Islands, Panama, 2013. C: Laysan Island, North Pacific Ocean, 2004. D: Catholic Island, Caribbean Sea, 2014. E: Siniya Island, United Arab Emirates, 2013.

Lavers and her team sampled micro- and macro-debris, including glass, wood, and metal items, along a total of 25 beaches that covered an area measuring 1,110 m2.

They recorded a total of 23,227 anthropogenic debris items, weighing a total of 96.67 kilos.

Data were collected from two beaches (lagoon and ocean facing) per island to capture the variability in debris density, and additional beaches were examined on the largest islands: West Island and South Island.

The debris categories included glass, foam, metal, hard plastic fragments, film (e.g. soft plastics such as bags), and threads (e.g. rope and fishing line). Additional sub-categories included readily identifiable items or those commonly reported in the recent literature (e.g. industrial resin pellets, melted plastic, shoes, cigarette lighters, and toothbrushes).

Debris on an ocean-facing beach on South Island. Photo credit: Emma Washer, Big Barge Art Centre. (The researchers were unable to gather data from this particular beach.)

The research was carried out in March and September 2017 and the team received assistance from Sea Shepherd’s Marine Debris programme, the Tangaroa Blue Foundation, and the Two Hands Project.

The scientists were also helped by local schoolchildren and other members of the community.

The southern atoll of the Cocos (Keeling) Islands is the largest and consists of a horseshoe chain of 26 islands around a shallow, central lagoon. The northern atoll (designated as Pulu Keeling National Park) is a rarely visited, uninhabited island that is an important breeding site for seabirds.

The seven islands studied account for 88 percent of the landmass of the Cocos (Keeling) Islands. 

Most of the inhabitants of the Cocos (Keeling) Islands are ethnic Malays living on Home Island, where the estimated population is five hundred. There are about one hundred ethnic Europeans living on West Island. 

1. A tonne is a metric ton, or 1,000 kilograms.

Plastic fragments in the surf on Christmas Island in the northeastern Indian Ocean. ©CSIRO, Britta Denise Hardesty.

Artwork created from debris by a Cocos islands resident. The ships are made of reclaimed timber, toothbrushes, and foam (from flip-flop shoes). Photo credit: Emma Washer, Big Barge Art Centre.