It is safe to say that many plastics will never completely decompose. The only real way that plastic has been proven to break down to a certain extent is through photodegradation which requires sunlight and time. And even this process will only break the plastic down into tiny little pieces.
In the ocean it takes up to 500 years to break plastic down into these tiny little pieces. With 80 million tons of plastic produced a year, there is now a blanket of plastic pieces sprinkled across the entire ocean.
Much of the plastic in the ocean is made up of big pieces of plastic such as plastic bags, bottles and bottle tops. As these pieces of plastic are weathered down by the conditions and sunlight over a long period of time it turns into these tiny little pieces called microplastics.
Above: A 0.0073 millimeters (a.k.a. 7.3 μm) piece of polystyrene seen inside the zooplankton Centropages typicus. Image: Environ. Sci. Technol.
The scary part about this is these microplastics don’t go away, they just spread out over time throughout the entire ocean. The microorganisms that decompose organic material down such as pieces of wood and seaweed are unable to breakdown a synthetic material such as plastic.
Microplastics are a relatively new concept to research scientists. Microplastics are hard to research as they are almost invisible to the naked eye but can be found in almost every part of our oceans.
Just as the big pieces of plastic are dangerous to larger marine life such as dolphins, whales, albatross, turtles, fish and many other larger marine life. Microplastics are toxic to the smaller marine life such as plankton that are feeding on these microplastics. Microplastic can become host to other toxic chemicals which plankton eat and either choke on or swallow and the toxic chemicals, along with microplastic, is then introduced to the food chain of the ocean.
The first survey of its kind in the world is working to monitor the amount of plastics in our ocean. The National Marine Debris Survey has found that 74% of the marine debris found around the Australian Coastline is plastic. This survey collects and analyses marine debris from around the country, sampling rubbish at 100 kilometre intervals around Australia’s 35,000 kilometer coastline.
Already this survey has found that there is 5.2 pieces of marine debris along our coastline for every person in Australia.
We can all do our part to preserve our beautiful ocean by consciously choosing to use less plastic eg. using biodegradable plastics, dumping less plastic in the oceans or cleaning up patches of the oceans strewn with plastic.
If you are interested in staying up to date visit The National Marine Debris Survey.