With the widespread use of plastic products, more and more plastics have been abandoned in the wild. About 40% of them finally drift into the ocean in various ways.
A 2010 survey estimated that about 5 trillion pieces of plastic debris floated in the ocean, with a total mass of about 4 million to 12 million tons. They pose a serious threat to marine animals. However, a recent survey showed that the amount of waste plastic floating in the ocean is much smaller than estimated, only 1/10 of the original estimate, and has remained at a stable level for many years. So where is the large amount of discarded plastic? It has been suggested that perhaps marine microbes have evolved the ability to degrade plastics.
In theory, this is not impossible. Marine ecologists have found that microbes that are parasitic on floating plastics look quite different from other marine microbes, and they believe that certain marine microbes may feed on plastics. However, subsequent DNA testing did not reveal any known marine microorganisms that could degrade plastics.
It has also been suggested that when marine organisms multiply on floating plastics, the plastics are too heavy to load, and finally sink into the sea floor, or under physical action, directly break into small pieces, so that they have missed the study ship. trawl. In addition, plastics may be eaten by large marine animals or washed by water into unknown seas. Under natural conditions, plastics typically have a degradation cycle of 200 to 400 years. In fact, if the degradation rate of plastics in the ocean is accelerated, it may not be a good thing. Plastics contain a lot of harmful additives. If they are released, they may enter the food chain and affect the safety of aquatic products.