When plastic was invented in 1907, nobody would have thought that one day the entire planet would be covered with it. Alarming reports of microplastics found in the placenta of unborn babies made their way to the news recently.
Plastic pollution is a real menace now, killing 100,000 marine animals and more than 1 million sea birds every year.
Garbage patches are formed in the calm centers of ocean gyres. They usually develop along busy shipping routes.
Did you know that the largest accumulation of ocean plastic in the world, called the Great Pacific Garbage Patch, lies between Hawaii and California? It spans ~ 1.6 million square kilometers.
Plastics of all kinds are released into oceans and other water bodies every day (8 million pieces!). Some of this plastic is transported across long distances by water currents.
Plastic is not biodegradable so it cannot be disintegrated by bacteria. Instead, it is broken down into smaller and smaller pieces called microplastics under the effect of the sun, waves, and marine organisms.
Plastic debris in the Great Pacific Garbage Patch don’t just float on the surface; some of the denser pieces sink a few centimeters to a few meters below the water surface.
The estimated weight of the patch is equivalent to 500 Jumbo Jets! (~ 80,000 tons)
Why are marine debris harmful?
Marine debris are harmful to the entire ocean ecosystem.
a) They block sunlight from reaching planktons and algae, preventing photosynthesis and thus production of nutrients. If the planktons and algae die, then the oceanic food chain gets disturbed. Organisms that feed on them in the chain, such as jellyfish, turtles, and sharks, cannot survive.
b) They’re mistaken as food by marine animals, causing malnutrition. The chemicals in the plastic also get accumulated in the bodies of the animals, called bioaccumulation. These chemicals can get transferred to humans as well when they eat marine species.
c) Marine animals get entangled in fishing nets and ropes, endangering their life. 46% of the debris in the Great Pacific Garbage Patch is made of fishing nets! Discarded fishing nets are called ghost nets.
What types of plastics are found in the Great Pacific Garbage Patch?
Four types of plastics have been found:
a) Microplastics (0.05 cm – 0.5 cm)
b) Mesoplastics (0.5 cm – 5 cm)
c) Macroplastics (5 cm – 50 cm)
d) Megaplastics (more than 50 cm)
Once plastic debris break down into microplastics, they are very difficult to remove from the oceans. Marine life tends to eat it, thinking it’s food.
Plastic sheets or films, fishing nets, plastic ropes, and plastic spheres or cylinders form part of the marine debris at the Great Pacific Garbage Patch.
Economic cost of the Great Pacific Garbage Patch
Deloitte and The Ocean Cleanup conducted a study to calculate the yearly economic costs of marine plastic–it runs to between US$ 6 – 19 billion. Tourism, aquaculture, fisheries, and government cleanups contribute to these costs.
The cost of the effect on marine life and humans has not yet been calculated.
What this tells us is that we can reduce the harmful impact of marine plastic by intercepting debris in rivers before it can travel to the sea.