Up to 12 million metric tons of plastic enters in the ocean every year. However, when scientists count floating plastic in the ocean, they only find 250,000 tons. So, where is all that missing plastic?
Factors such as sunlight, oxygen or weathering will degrade plastic that will break into small pieces (microplastics) and will spread around the world travelling with the marine currents. The nets that scientists use to “fish” plastic have a mesh size of 200 µm. That means that plastic pieces smaller than that size won’t be collected and counted. So, part of the missing plastic could be making part of that small size fraction that has not been quantified. Then, some plastics sink and the scientist’s nets only recover those pieces that are floating. Plastic types with higher density than seawater (e.g. PVC) will sink. But even those with lower density could eventually sink as well.
The colonization starts as soon as the plastic reach the sea.
Tiny microorganisms will start to stick to the plastic and use it as their home and vehicle. Microscopic algae, fungi, bacteria… all them stick to the plastic surface forming a biofilm that covers the piece. Those colonizers drift until they reach other parts of the ocean where they can bloom, altering the new ecosystem. And with so many colonizers, the plastic weight can increase and sink. All that sunk plastic has not been counted either. And other plastics that have not been counted are those which are in the interior of animal bodies or even… in our own body!
But why animals eat plastic?
Some of them, the filter feeders, do it unconsciously when they eat. They filter water with everything that is on it. But other animals, like seagulls, eat it semi-unconsciously, by mistake. Plastic colonization by microorganisms happens very quickly. And some of the “colonizers” emit gases that smell as the prey of those bigger animals. So, they eat them thinking they are eating their prey. If the animal that ate the plastic is intended for human consumption, plastic could end up in our stomach. But even if you are vegan, you could end up eating plastic since it has been also found in the table salt.
Best option: Reduce our utilization of single-use plastics.
Nowadays, it is difficult to live without plastic, which makes our life easier and cheaper. But every time we use a plastic item, we should think for how long we will use it and for how long it will remain as a waste in the environment. Besides improving plastic management and recycling, we, as individuals, should reduce the utilization of single-use plastics wherever possible. It is better to not generate a waste than to have to manage it afterwards.