The Less Well-Known Effects of Plastic in the Ocean
Brookline, MA
2014, Senior, Creative Writing
One of the most important current topics for discussion regarding the environment is the cleanliness of the ocean. Nearly all organisms rely on the ocean in some way and so the ocean’s health and well-being should be one of our top priorities. Over the years, a number of regulations and policies have been implemented in many countries in order to protect the ocean from harmful substances such as pesticides, industrial waste, and untreated sewage. These regulations are obviously beneficial and have helped promote cleaner waters, but there are other factors that must be addressed that directly affect the ocean’s health. Plastic, for instance, is dumped into the ocean on a regular basis, yet there have been few regulations to decrease the amount of plastic waste entering the ocean. Additionally, more plastic is produced every year as a result of increased demand which leads to greater quantities of plastics in the ocean. Plastics are detrimental to aquatic ecosystems for a number of different reasons: they may entangle animals, smaller pieces may be ingested by aquatic organisms, and they may even create anoxic areas in the water.
Many well-informed people are familiar with the pictures of marine organisms scarred or entangled as a result of larger pieces of plastic pollution. Many people are also well-acquainted (though less well-acquainted) with the pictures revealing the irregular stomach contents of marine birds and fish. Through these pictures, we are able to understand that plastic in the ocean is generally bad for aquatic ecosystems and organisms, but we fail to realize that there is much more to the issue than what the pictures show us. The presence of plastics in the ocean has the potential to negatively impact organisms that do not even ingest the plastics themselves – organisms that, we may find over time, include us. By becoming familiar with the less well-known reasons as to why plastic is so detrimental to the environment, governments and policy-makers as well as the general public will be able to take steps to ensure the future cleanliness and health of the ocean. In the process, we will be working towards healthier living conditions for organisms, including humans.
A property of plastic that researchers have only just started to investigate is plastics’ ability to absorb certain toxins and chemicals in the ocean. As a result of fertilizer runoff from agricultural areas, chemicals released by industrial complexes, and a number of other sources, toxins in the ocean are widely prevalent. For instance, a widely used pesticide, DDT, has been found in coastal waters near farms. DDT is an endocrine disruptor – meaning it affects the hormone levels of the organisms with which it comes into contact. While the purpose of DDT is only to kill the pesticides eating the crops on land, DDT can enter other ecosystems, such as the ocean via runoff, and harm the organisms there. This is partly due to the fact that DDT is very persistent in the environment and takes a very long time to break down into less harmful substances. So how is DDT related to plastic? Due to plastic’s ability to absorb toxins in the water, DDT be absorbed by the plastic in high concentrations. Other chemicals, such as PCBs, dioxins, fertilizers, and furans, and heavy metals, such as lead and mercury are also absorbed by plastic in the water.
The absorption of toxins in plastics in the water poses such a large problem because of two natural phenomena: bioaccumulation and biomagnification. Bioaccumulation occurs when an insoluble substance is ingested by an organism. Because the substance cannot be flushed out of the organism as a result of its insolubility, the substance will accumulate in the organism’s fatty tissues. The other phenomenon, biomagnification, is a result of inter-trophic level bioaccumulation. When an insoluble substance bioaccumulates in the flesh of an organism in a low trophic level and an organism in a higher trophic level eats the first organism, the organism in the higher trophic level will absorb the substance the first organism once ingested (Castro 2010). Biomagnification specifically occurs because organisms in higher trophic levels need to consume more for energy and will ingest many of the organisms that have been exposed to harmful substances. As a result, higher levels of toxins bioaccumulate in the flesh of organisms in higher trophic levels. This results in biomagnification. When plastics absorb toxins in the water and these plastics are ingested by an organism in a low trophic level, through biomagnification, the organisms in higher trophic levels are exposed to very high levels are toxic substances (Castro 2010).
While the biomagnification of toxins in the food chain are indubitably harmful to the organisms that ingest them, these toxins may also have a detrimental effect on humans though this has not been confirmed as of yet. We have already recognized that mercury, a heavy metal and neurotoxin that bioaccumulates in the flesh of fish, can do us serious harm if we eat fish in higher trophic levels, such as tuna. From this, it can be concluded that other toxins and heavy metals that are biomagnified in the marine food chain can likewise be harmful to humans. With the increasing amount of plastic in the ocean comes a potential harmful side effect: an increase in the toxicity of the fish we eat. We can blame no one but ourselves for this problem. Humans are both responsible for the releases of DDT, PCBs, dioxins, fertilizers, and furans, lead, and mercury, and for the dumping of plastics into the ocean. These toxins, including endocrine disruptors and neurotoxins, can potentially hurt or kill humans.
A question concerning the ingestion of plastics by marine organisms is why these marine organisms are ingesting the plastics in the first place. Part of the problem is that plastics are very persistent in the environment – meaning that the plastics in the ocean and on land take a very long time to break down. Another one of the major problems with the increasing presence of plastic in the ocean is that fish and other marine organisms are unable to distinguish between pieces of plastic and food depending on the size and color of the pieces of plastic. In fact, it is much more common for a fish to ingest plastic than it is for that same fish to become entangled in its lifetime. The only reason the public is much more familiar with marine wildlife entanglement is because this problem is easily recognizable and understood. A picture of a sea bird entangled in a plastic bag is more moving than a picture of a fish’s stomach containing plankton and plastic pieces. Nevertheless, marine wildlife’s ingestion of plastic is a more serious issue than marine wildlife entanglement. Typically, a fish swallows both plastic in the water as well as plankton when feeding. If a given fish is unable to digest the plastic in its gut, this can lead to starvation and malnutrition for the fish. Additionally, the toxins absorbed by the ingested plastic material can do the fish harm. We have already seen that sea birds (as well as other marine organisms) have been negatively impacted by the presence of toxins in the ocean. We should assume that if other organisms suffer from these toxins, humans will inevitably suffer as well.
Aside from the biomagnification of toxins as a result of plastic pollution in the ocean, the presence of plastics in the ocean has a number of less-well-known harmful effects that are important to understand. Plastics have high thermal and electrical insulation properties. This could result in areas of irregular water temperatures where plastic pollution is present. Furthermore, because of plastic’s buoyancy, plastics tend to float to the water’s surface. Plastic then inhibit gas exchange between the atmosphere and the water. This leads to hypoxia and anoxia which then leads to marine animal death and ecosystem destruction. When plastic washes ashore on beaches, it often mixes with seaweed and other things in the ocean to form wrack which accumulates on the sand. Plastic on beaches is an eyesore to those who use them and in an effort to clean the plastic off the beaches, people have historically removed the wrack entirely from the beaches and disposed of it. This is detrimental to the environment because wrack serves as the habitat of a diverse group of beach-dwelling organisms. By removing the seaweed from the beaches with the plastic, one is destroying their habitat.
Unfortunately, very few policies and regulations have been enacted to decrease the amount of plastic waste dumped into the ocean and those that have been enacted are only somewhat helpful. In truth, it is hard to regulate the amount of plastic that enters the ocean because plastic comes from many different sources on land. Nearly all humans litter to some extent. Nevertheless, there are a number of different and important steps one can take to reduce the amount of plastic that enters the ocean. For a typical civilian, refraining from using plastic materials and recycling the plastic one does not use are the two best ways to keep plastic out of bodies of water. Furthermore, governments and policy-makers should work to enact laws against the dumping of plastics in the ocean. Some city governments, such as the city of San Francisco, have already placed bans on certain plastic objects like plastic bags and other select plastic items (Plasticbaglawsorg). While this will not stop the problem of plastic in the ocean entirely, it is still helpful because it inevitably leads to a decrease in plastic pollution in the ocean and local bodies of water. The path to a plastic-free ocean is not a difficult one though it does require substantial cooperation between law and policy makers and the general public. Nevertheless, what many do not realize is that limiting the amount of plastic that enters the ocean is for our own benefits. Humans, as much as any other organism on Earth, rely on the ocean in some way for survival. By taking the steps to promote and protect the health of the ocean, we ultimately take the steps to promote and protect our own health as well as the health of the entire Earth.