‘’The marine ecosystem’’ is a complex of living organisms in the ocean environment. Contrary to common belief, ‘’the Lungs of the Earth’’ are marine ecosystems, not forests. Prochlorococcus bacteria living in the oceans perform photosynthesis - the source of oxygen - and this "unseen hero" produces 20% of the oxygen in the biosphere. This rate is higher than the sum of the rainforests. Our world is such a rich source of oxygen because of these bacteria and by extension, marine ecosystems. In addition, billions of tons of carbon dioxide gas, one of the leading causes of global warming, are absorbed by the seas and oceans every year.
"With every drop of water you drink, every breath you take, you're connected to the sea. No matter where on Earth you live. Most of the oxygen in the atmosphere is generated by the sea."- Sylvia Earle, Oceanographer
Marine pollution is defined as the pollution that occurs as a result of the discharge of all kinds of waste, predominantly plastic waste, which harms the marine ecosystem, negatively affects all activities in the seas and oceans, and generally reduces the quality of the water.
Plastic debris constitutes approximately 80% of marine litter. It is estimated that approximately 150 million tons of plastic garbage float in the oceans and seas. An additional 6.5 million tons are added each year to this threatening accumulation. According to the UN Environment Programme data, an average of 13,000 pieces of plastic fall per square kilometre in the open sea. Streams also cause this plastic debris to spread to every corner of the world. When plastic debris reaches the seas and oceans, it continues to exist for centuries due to its high decomposition temperatures and resistance to ultraviolet rays and bacteria. This situation causes high risks for people, biodiversity, and the ecosystem.
When plastics are exposed to the hydrodynamic scour, they gradually break down into pieces less than 5mm in radius, called micro-plastics. Most of the micro-plastic debris consists of not sustainable and non-biodegradable synthetic tissues that come from textile products (especially fast fashion products), catalyst particles from detergent, cosmetics and chemical production, particles from plastic bags, plastic wastes from grinding-chipping processes, and wear and tear particles from tires. These micro-plastic wastes are dragged into rivers, seas and oceans by sewage and rainwater and spread worldwide through streams, worsening marine pollution.
"It's difficult to picture an amount that large, but if you could imagine laying out all that plastic across a flat surface, it would cover the area of the UK 1.5 times. It's complex [to calculate] because plastic is everywhere and, in every part of the world, it's different in terms of how it's used and dealt with," says Dr Costas Velis from the University of Leeds
Disposal of solid wastes with problematic methods.
Inadequate waste management (for this reason, the collection, transportation, treatment, and final discharge of wastes are inconvenient).
Untreated sewage discharge and inadequacy of treatment facilities.
Industrial waste discharged irresponsibly.
Fish farming (net cages, building materials, feed sacks are left in the water due to these farms).
Commercial fishing, fishing tackle and throwing nets, Styrofoam attached to nets.
Offshore oil and gas platforms (drilling tools, pipes, drums, packaging left because of these platforms)
Tourism and leisure activities [as a result of these irresponsible actions, plastic waste (bags, product packaging made of plastic, bottles, lids, toys, balloons, etc.) and other solid wastes are consciously or unconsciously left on the beach].
Recreational shipping (small boats used for fishing, yachts, water sports) and garbage such as bottles, wastewater, fishing rods, sports equipment left in the sea and oceans as a result of such activities.
Commercial and free shipping (large cargo ships, cruise ships, ferries) [The wastewater discharges of these ships and the cargo left or dropped into the sea during the voyage.]
Land-based litter from streams, canals, sewer outlets, floods, wind, and tides
"The sea, the great unifier, is man's only hope. Now, as never before, the old phrase has a literal meaning: we are all in the same boat." - Jacques Yves Cousteau, Oceanographer
Why is plastic pollution a critical problem?
A plethora of organisms ingest micro-plastics floating in the water. The toxic substances therein become a link in the food chain through sea creatures that swallow these particles and ultimately reach humans. It is not easy to separate these invisible plastics from the micro-level sea creatures and clean the ocean from this pollutant.
Recently, Dutch scientists detected the presence of microplastics in human blood for the first time. As a result of the tests carried out by the Vrije Universiteit Amsterdam academicians, microplastics were detected in the blood of 17 of the 22 people who participated in the study.
Regarding the previous research, it was already known that humans could ingest microplastics through food and water. Moreover, the particles can also be found in faeces and the placenta. In fact, it was detected that the microplastic rate in babies' faeces was 10 (ten) times higher than that of adults.
In addition to the above, plastic waste in the marine ecosystem can cause an increase in the spread of harmful chemicals that threaten human health, cause injuries, and spread infectious diseases.
Macro-plastic wastes reaching the seas and oceans cause the suffering and death of marine mammals, sea turtles, reptiles, fish, and seabirds as they are often mistaken for food. For example, sea turtles can eat plastic bags, which they think are jellyfish, algae, or other species that are the components of their diets. Moreover, seabirds are likely to feed themselves and their offspring with plastics they mistake for fish eggs or crab. As a result, living things that fill their stomachs by eating garbage are exposed to starvation and die from lack of nutrients. In addition, the plastic wastes that are eaten cause the creature to die of suffocation by blocking the respiratory tract.
Marine mammals and sea turtles can get caught in fishing nets left in the seas and the oceans. This trap causes these creatures to suffer immensely, face severe injuries and eventually die.
As stated before, plastic and other solid waste can travel far from their original source by travelling via streams, waves, winds, and flows. Consequently, it is possible to see plastic waste even in uninhabited areas. For this reason, it is almost impossible to follow the route and direction of plastic waste, such as where it was formed, what happened to it on the way, and why it came to the place it reached. Furthermore, microplastics that are out of sight also are not accessible, reaching an inevitably unsolvable situation.
How do countries act with regards to plastic pollution?
Unfortunately, approximately 14 million tons of plastic end up in the marine ecosystem annually, and plastic makes up 80% of all marine debris found from surface waters to deep-sea sediments, while plastic waste can be found on the shorelines of every continent.
Many countries lack the infrastructure to prevent plastic pollution in terms of sanitary landfills, incineration facilities, recycling capacity, circular economy initiatives, and proper management and disposal of waste systems. This situation leads to ''plastic leakage'' into seas and the ocean, resulting in the deepening of marine pollution. Furthermore, both legal and illegal global trade of plastic waste holds the power to damage ecosystems, where waste management systems are not adequate to contain marine plastic debris and microplastics.
Marine plastic debris contributes to the catastrophic events of climate change. If plastic waste is incinerated, it releases carbon dioxide and methane (from landfills) into the atmosphere, thereby increasing emissions. Therefore, the UN 2030 Agenda for Sustainable Development calls for action to ''Conserve and sustainably use the oceans, seas and marine resources'' (Goal 14) and ''By 2025, prevent and significantly reduce marine pollution of all kinds, particularly from land-based activities, including marine debris and nutrient pollution'' (Target 14.1).
The United Nations Environment Assembly (UNEA) is expected to take steps toward creating a landmark treaty to regulate plastic pollution all over the world. At UNEA, the negotiators are scheduled to discuss suggestions and proposals for legally obligatory restrictions on the usage and disposal of plastic. The action is part of a more considerable international effort to prevent plastic pollution.
The Basel Convention has been the superior international, legally binding mechanism underlying plastic pollution. It regulates the transboundary movement of plastic waste and pledges countries to address plastic pollution better. As part of the Basel Convention, countries declared 2019 the Partnership on Plastic Waste, which has invested in 23 projects planned to stem plastic pollution and encourage businesses to re-use products made of plastic.
“I watched the coral reefs that I studied as a student vanish in the blink of an eye, and for decades I wrote and spoke of ocean obituaries. But big scary problems without solutions lead to apathy, not action…. Small steps taken by many people in their backyards add up.” - Nancy Knowlton, coral reef biologist, and Sant Chair for Marine Science at the Smithsonian Institution
What can we do to reduce plastic pollution?
First, we should demand that legal frameworks and regulations are put in place with envisaging sanctions when plastic pollution-regulation is breached. At this point, governments and municipalities have a great responsibility. In this regard, laws and regulations should be enacted to reduce plastic and other waste. These laws and regulations should be of a nature to improve waste management. Furthermore, awareness-raising activities should be carried out, and non-recyclable plastics, especially plastic bags, should be taxed and banned - as many countries already have done or are doing within the 2020s. Efforts to encourage and facilitate recycling must be implemented, and the manufacturers should be held responsible for recycling. Global efforts should also be regulated to adhere to and strengthen international legislative frameworks covering marine plastic pollution.
In this direction, manufacturers should feel responsible for recycling and producing packaging and products suitable for recycling that can be repeatedly used.
“At the end of the day, the government and local government all bow to public pressure…. [Regulatory] enforcement is weak, and environmental litigation is near to impossible. So, there’s an urgent need for extensive public participation to generate another kind of motivation.” - Ma Jun, environmentalist, journalist, and National Geographic Explorer
As conscious people, of course, we should make an effort to prevent plastic pollution. We must not forget that all ecosystems are interconnected. So, what can be done individually?
Never throw garbage in streets, riversides, seas, and oceans.
Buy products that require the least packaging and/or choose zero-waste alternatives.
Avoid using nylon bags and prefer reusable mesh bags and pouches.
Avoid using disposable cups, plates, and similar materials.
Prefer clothes and fabrics made of natural fibres as synthetic ones break down over time, leading to the formation of microplastics.
Not release products such as balloons or wishing lanterns into the air since these soon become garbage on land and in marine ecosystems.
Closing thoughts
Needless to say that solutions for marine pollution contain prevention and clean-up. Unfortunately, single-use plastic is used in large quantities in today's society, even though there are regulations restricting plastic usage. In this case, society's approach to changing plastic use is necessary, although it is very long and economically challenging. Moreover, the clean-up process is extremely difficult (maybe impossible for some items) since some types of plastic debris do not float but are lost deep in the marine ecosystems by turning into microplastics. Therefore, we must reduce our plastic usage by choosing sustainable and zero-waste alternatives, educating people about the devastating effects of plastic pollution, helping initiatives that clean our oceans and demanding more in terms of strict regulations on preserving nature from governments and international organisations.