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How the ocean is under threat from plastics pollution.

It is not uncommon to see images or videos online of turtles trapped in plastic six-pack rings or with plastic straws stuck up their nose; however, whilst this is terribly damaging, it is not the only threat to marine life caused by plastic pollution. Other ways plastic can affect marine life are ingestion, biomagnification, bioaccumulation, habitat destruction and chemical pollution.

Entanglement and Injury

Any type of plastic in the ocean can lead to animal entanglement but plastics that are manufactured in loops are often the most dangerous. Plastic loops can easily become hooked around the limbs, body, neck and even in the mouth of marine animals. Prolonged entanglement can lead to severe pain in the long term for animals as it can cause ulceration and deep laceration of underlying soft tissues. For any air breathing animal, death can come a lot quicker when entangled as the plastic can inhibit their access to the surface leading to asphyxiation or drowning. Fishing gear is a leading component of ocean plastic, making up approximately 20% of all marine plastic and is the largest identified cause of death due to human activity for minke and humpback whales in Scottish waters.


Microplastics are tiny pieces of plastic less than 5 millimetres in size, and they are a growing environmental problem in the ocean. Microplastics are formed when plastics break down into small particles under the influence of many factors such as wind, currents and UV radiation. Due to their size, microplastics are very easily mistaken for food by animals such as fish, turtles, and birds. When ingested, microplastics can have a damaging effect on animals as it can reduce food intake, delay growth and cause oxidative damage


Even life at the bottom of the food chain such as fish larvae and plankton ingest microplastics.

Bioaccumulation is the increasing concentration of persistent, toxic substances in organisms at each level, from the bottom of the food chain to the top. These are substances that are fat soluble, not water soluble, and are stored in the fat reserves of each organism.

Microplastics accumulate in animal fat and tissue as they move up the food chain and this leads to an increase in toxic chemicals absorbed by microplastics within marine animals.

Not only are these toxic chemicals damaging to the health of animals, but they can then be transferred to humans via the consumption of animal products.

Chemical Pollution

Tel Aviv University found that microplastics can absorb and concentrate toxic organic substances and increase their toxicity by a factor of 10 when in marine environments. During the manufacture of certain plastics, chemicals such as BPA and Phthalates can be added to the product. In general, microplastics act as a transport system for toxic chemicals through the food chain. They can attract and concentrate toxins. Once this plastic is in circulation these chemical additives can be released into aquatic systems. They are often harmful, sometimes deadly to marine life.

Is it really such a problem?

When disposed of incorrectly, plastic can become a huge problem for the ocean and marine life. Over 14 million tonnes of plastic end up in the ocean every year according to IUCN – the equivalent of around 63,000 commercial aircraft. This colossal amount of plastic can affect marine life in the ways described above.

It is estimated that ocean plastics kill roughly 100,000 marine mammals every year.

What is the Solution?

Plastic litter generally originates from land and ends up in the ocean via wind, rain, boat littering, river littering as well as people’s behaviour on the beach

Pollution from microplastics it is not new. Their size makes them incredibly difficult to clean up, and we have reached the point where no amount of money or technology can do more than skim the surface of the problem (literally in some cases).

While we, as consumers, can reduce our single use plastic consumption, this will only go so far.

This is why, despite the efforts of industry and consumer brands to dilute the outcome, the Global Plastic Treaty that is currently being negotiated must succeed in cutting the problem off at source and limit the production of plastics. We must lobby decision makers to Turn off the Tap on single use plastic.


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white and blue ocean waves - Photo by Matt Paul Catalano (ST ref: 1313)

turtle caught in a drift net - Image by Sébastien Stradal for MDC Seamarc Maldives (ST ref: 1190)

school of fish in plastic - Photo by Naja Bertolt Jensen (ST ref: 1181)

Impact of marine plastic in the microbial loop - Image by Frontiers in Marine Science (ST ref: 1203)

Discarded plastic bottles - Image by mbeo (ST ref: 1299)`


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