Plastic Peril

The accumulation of plastic litter floating in our oceans has increased over recent years; Tiina McVarish considers the devastating impact it can have on the wider marine environment and reminds us to dispose of plastic more thoughtfully to help ensure the wider marine environment does not suffer from our own behaviour.

The most visible and widely recognised effects are those caused by macro-plastics, the larger items such as plastic bags, six-pack plastic rings, cigarette lighters and old fragments of nets etc. Various marine species have not only been trapped in, or strangled by the rubbish whilst feeding, but have also mistaken it as food. As the plastic is ingested it sits in the stomach and reduces the overall volume of the stomach and consequently the nutrient intake, thus starving the animal slowly. Along with this it may block the intestinal tracks and cause serious internal injuries.

However, there is more to the plastic pollution than meets the eye. Deeper under the surface water unknown quantities of plastic is floating and breaking down into smaller particles, micro-plastics (polymers) causing further destruction to the marine biota. Some scientists have already found these polymers at the base of the marine food-chain, in the digestive system of zooplankton and other filter-feeding organisms. As these organisms may be eaten by larger predators, the plastic will not only be directly ingested, but also through eating other animals already affected by the pollutant.

The polymers are also, due to the microscopic size, easily shifted by the currents to various parts of the ocean entering more open feeding grounds, thus becoming food for a greater variety of marine species.

As with the macro-plastics the some of the effects of digesting micro-plastics are long-term. In addition to the deleterious effects already mentioned, scientists have attributed the following to plastic ingestion: reduction in the number of species in localised areas subject to heavy plastic pollution; reduction in the overall size of an animal; increase in toxin levels in the bloodstream or internal organs; disruption in the reproductive behaviour and alternation in hormone levels. Effectively the plastic pollution may not only affect current generations, but additionally generations to come.

The effects we have on our wider environment are increasingly becoming evident. As some studies point out, over half of the debris found in our oceans is land based. Those plastic bottles, bags and other debris left on the shore on purpose, or by accident, contribute to the effects mentioned above. Perhaps it is easy to think that surely one bottle left on the shore will do no harm. However, there never is just one piece of plastic rubbish, nor is there just one effect.

Originally from Finland, Tiina has been involved in many outreach programmes, often working with children.

A constant fascination with the marine environment however led her to further her education and Tiina is currently a student with the University of the Highlands and Islands studying Sustainable Rural Development.  Tiina’s main interests lie with sustaining rural fishing communities and the impact of plastic pollution on the marine environment.

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