Amelia Cutting

Last week, a study lead by Linsey Haram on the establishment of coastal species in oceans has found marine animals, among many other organisms, living on a plastic patch in the Pacific Ocean known as the ‘Great Pacific Garbage Patch’. 

What is it?

The ‘Great Pacific Garbage Patch’ (GDGP) is the largest accumulation of ocean plastic in the world.

It covers an estimated surface area of 1.6 million square kilometres and is located halfway between the coast of Hawaii and California.

How has this ‘plastic patch’ formed?

Some areas of the ocean have circulating currents that cause floating debris to accumulate and form a ‘gyre’. The world has around 5 plastic-infested gyres, though the GDGP is thought to have the most.

Around 1.12-2.41 million tonnes of plastic are entering the ocean each year from rivers- over half of this is less dense than water which means it does not sink once it enters the sea. Instead, it is transported over large distances by these converging currents, eventually accumulating on the patch.

Once they enter the gyre, they are unlikely to leave again until they degrade into smaller microplastics under the effects of sun, waves and marine life. Once they become this small, they are difficult to remove.

Lead researcher of the study Dr Linsey Haram said: “plastics are more permanent than many of the natural debris that you previously have seen in the open ocean. They’re creating a more permanent habitat in this area.”

How was the study conducted?

One of the most elaborate sampling methods ever coordinated was used to gather data for this study:

It consisted of 30 boats, 652 surface nets and two flights over the patch to obtain aerial imagery of the debris. Using data from multiple missions, a mass concentration model was produced to visualise the plastic distribution in the patch.

“We want to get a handle on how plastics may be a transport for invasive species to coasts”, Haram told BBC News.

The researchers reported their findings in the journal Nature Communications and initially embarked on the investigation following the Japanese tsunami of 2011 which left hundreds of coastal Japanese marine species alive on items that landed in the shores of the North American Pacific coast and the Hawaiian Islands.

What do the results show?

Anemones, tiny marine bugs, molluscs and crabs were found on 90% of the debris.

Some of the organisms found were open-ocean species- organisms that survive by ‘rafting’ on floating debris. However, the most eye-opening finding, according to Dr Haram, was the sheer diversity of coastal species on this plastic:

“Well over half of the items had coastal species on them,” she said. This is another “unintended consequence” of plastic pollution and a problem that is expected to grow in the future.

What are the dangers of plastic in the ocean?

Due to the size and colour of the plastic in the ocean, animals often confuse it for food.

It also poses entanglement risks, threatening their overall behaviour, health and existence.

For example, sea turtles by-caught in fisheries operating within the patch and around it, can have up to 74% of their diets composed of ocean plastics, and since 84% of this plastic was found to have at least one Persistent Bio-accumulative Toxic chemical, animals consuming it are ingesting the chemical and putting themselves at risk.

Through a process called bioaccumulation, chemicals in plastic enter the body of the animals feeding on it, and, as the feeder becomes prey, the chemicals pass to the predator, making their way up the food web, another risk posed.

Visit the Greenpeace website to find out how you can help prevent plastic pollution in our oceans.

Featured image courtesy of Rohit Tandon via Unsplash. Image licence can be found here. No changes or alterations were made to this image.

I'm Amelia- a graduate from the University of Leeds and current NCTJ Level 5 Diploma student!

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