Without any hesitation, the answer is yes. The oceans are in danger, largely because of plastic waste and microplastics. But not only. Other sources of pollution add up, combine and increase the irreparable damage to marine fauna and flora.
What are the pollutions causing this ecological disaster? What can we do to save our oceans and keep the planet cleaner ?
Who are the polluters of the seas?
Almost everything that is dumped into the sea is harmful. Apart from organic waste, such as apple peels, the marine ecosystem is not designed to receive toxic or plastic materials. The incredible ability of the sea to repair and renew itself allows it to survive pollution… up to a certain point. Today, pollution is too diverse, constant and significant for the oceans to absorb it.
This is the case of plastic that accumulates there. Overall, we differentiate between waste and objects brought by humans (or the wind) such as plastic bottles, and chemical substances that arrive through wastewater in some parts of the world where sewers and treatment plants are lacking (detergents and shampoos end up in the ocean).
In our country, it is the storm water networks that cause a cigarette butt thrown into the gutter in the city, or bleach used to clean a porch and rinsed in the street, to end up in the sea… Beyond the ecological aspect, the contamination of sea water by waste water poses a worrying health problem for bathers. Indeed, bacteria cause diseases ( skin , respiratory, diarrhea) in millions of cases per year in polluted seas.
Contaminating industrial waste
Of course, the oceans suffer from all the waste that is dumped into them, whether it is toxic wastewater, or various polluting materials such as industrial waste or mixtures from construction that are made of paints, solvents or unused concrete, or materials that contain heavy metals and a lot of plastics . These plastics often come from coatings, which are impossible to extract from the sea: varnish, plastic films, degraded plastic waste, etc. They can circulate via wastewater, but also carried by the wind when they are stored in the open air. Wind and rain quickly cause plastic dust to arrive in a waterway.
What are dead zones?
Chemicals discharged by wastewater, by factories or when they are carried by rain from farms that use pesticides, cause all life to disappear in the area where they are discharged. Terrestrial or aquatic flora perish on the spot, as do "fixed" organisms, corals that cannot move or even certain marine animals that move too slowly to change habitat. When the water is not renewed quickly enough, this phenomenon creates the famous dead zones or "hypoxic" zones whose low oxygen content leads to the irreversible destruction of ecosystems. There are hundreds of them, of varying sizes, whose surface area can reach that of the United Kingdom! The first dead zones were located in the 1970s in the United States and in the Black, Adriatic and Baltic Seas in particular, where only primitive bacteria survive. In the Gulf of Mexico, the products dumped by the Mississippi River have wiped out all marine life over an area of about 25,000 km, making it the largest dead zone on the planet.
Oil spills, a chronic ecological disaster
In the same vein, oil spills are ecological disasters that some officials try to minimize while they destroy marine life. These "disasters" are most often the result of human negligence , themselves due to an economy of means to secure the routes of ships. Beyond the accidents of oil platforms at sea which can experience oil leaks, oil spills come from aging ships (like the famous Liberia and Panama). These ships, which should no longer be authorized to transport hydrocarbons, play on the differences in legislation between countries to remain active on our seas. In addition to the risks of oil spills, some illegally dump the oil from their tank bottoms into the open sea to avoid maintenance. Knowing that the consequences of an oil spill can last for years, we can say that the ocean is "chronically" polluted by hydrocarbons.
What about cigarette butts and small plastic waste?
On our scale, every small polluting action repeated by millions of individuals becomes a major problem, especially when plastic is involved. We immediately think of cigarette butts crushed in the sand (yes, yes, still today), but also of bottle caps, lollipop sticks and other packaging that holidaymakers leave behind. Because of its toxic substances (arsenic, lead, tar, etc.), a cigarette butt alone pollutes 500 litres of water. Its filter, made of cellulose acetate (a plastic fibre), takes more than 15 years to decompose. Which gives turtles plenty of time to gobble it up. We know how to recycle cigarette butts and transform them, but they must first be collected. This collection has a cost and recycling channels must be profitable before being set up. In some countries such as Great Britain, this channel is financed by the tobacco industry. In France, it is collective and personal initiatives that ensure the collection of cigarette butts and small plastic waste on the beaches. Because once in the sea, they are there forever.
Shampoo and sunscreen in the dock
When we swim, we also leave behind... our sunscreen ! Invisible, it spreads in the water with each swim. The problem? Whatever the filters, they alter marine flora and fauna. In particular, chemical sunscreens (called organic) kill (or bleach, it is said) coral and all the organisms that live in symbiosis with it. Water-soluble filters disperse in the water and are ingested by marine animals. Finally, the natural filters (called mineral) of organic formulas, made from zinc dioxide or titanium dioxide powders, sink and settle on the seabed and its inhabitants. These so-called biodegradable formulas would be "less bad" but no one has yet had the hindsight to confirm this. On the packaging side, we can no longer count the caps and other tubes of cream that end up buried under the sand at the end of the day, to which are added the silicones of hair formulas that behave like plastic and are released into the rinsing water without necessarily being able to be filtered. These invisible substances also harm marine life, fauna and flora and unbalance their exchanges.
Plastic in the sea, a floating monster
The first 4 polluting objects found in the sea are plastic:
- The cigarette butt
- Packaging
- Plastic bottles
- Plastic bags
They are followed by polystyrene and its small white balls (which animals take for food), plastic cutlery, sanitary towels, diapers and cotton buds. Plastic waste is the number one problem of marine pollution.
An indestructible composition
Covered with "polymers", chemical molecules as well as additives and "adjuvants" that are used to give it different characteristics (color, shape, flexibility, etc.), plastic is a concentrate of oil. It is polluting from A to Z, throughout its life cycle from its manufacture which requires many components that are extremely harmful to the planet to its use where these substances can spread or contaminate humans (such as endocrine disruptors such as Bisphenol A) until its death, which is relative because... it never disappears! It is transformed, recycled, dispersed into smaller and smaller fragments, until it becomes invisible microplastics, but it is still there.
A decomposition into fragments of micro plastics
Plastic has the defects of its qualities: it is strong enough to last, but not strong enough to not degrade. Unfortunately, it is used a lot to create objects that are not intended to last, or even intended for single use: it takes longer to make them than to use them. And this plastic is never assimilated into nature, unlike other materials that can integrate biogeochemical cycles. Metals or stone can return to the earth. Paper, cardboard, cotton and leather are assimilated by soil microorganisms. Plastic, on the other hand, only reduces itself to smaller and smaller pieces to end its life as micro flakes that infiltrate everywhere. In the sea, plastic waste and other objects are eroded by salt, ultraviolet rays, the heat of the sun, waves. They transform into micro-plastic crumbs, invisible to our eyes, and invade marine ecosystems. All these fragments of hard plastics, packaging, synthetic textile fibers make the sea a real plastic soup in certain areas. Some sink and cover the seabed and its plants, others float blocking exchanges with the surface of the water. Unfortunately, most of them are taken for food by fish.
How did the plastic continents appear?
Along with the great currents, microplastics are gathered in "gyres", immense plastic soups, real floating monsters to form expanses that we call "plastic continents" or the 7th continent. In the first gyre, discovered in 1997 in the Pacific Ocean, the density of plastic is 6 times higher than that of plankton. Today, there are 5 major plastic continents, in the North Pacific, the South Atlantic and the Indian Ocean, but also smaller ones near us. The Mediterranean is an almost entirely enclosed sea, so much so that plastic waste concentrates there and endangers its incredible biodiversity including marine mammals such as the dolphin, the fin whale or the sperm whale that live there. This phenomenon is particularly alarming in the Pelagos Sanctuary, a maritime area of 87,500 m2 located in the Corso-Ligurian-Provençal basin, classified as a "specially protected area of Mediterranean importance" (SPAMI). Indeed, plastic does not stop at maritime borders. This invasion can only be stopped upstream, by changing our habits and encouraging public authorities to implement strong and specific ecological policies.
Microplastics also pose a risk to human health
Beyond the ecological disaster created by microplastics in the oceans, there are also health risks for us humans. Marine organisms consume these fragments of plastic unintentionally: if we in turn consume these affected crustaceans and fish, we in turn ingest them. This is how a WWF survey reveals that we ingest nearly 5 grams of plastic per week: the equivalent of a credit card! This plastic ingestion also comes from bottled water and crumbs that we can swallow after cutting food in a plastic tray, a melamine plate (a heavy and unbreakable resin plastic material) or on a plastic cutting board.
To return to the ocean, the most worrying thing today is the "Plastisphere" phenomenon: plastic attracts organisms and bacteria that organize themselves into a new ecosystem, some of which are pathogenic agents for living organisms, such as vibrio (a bacillus of which a particular species is responsible for cholera) which can become the carrier of toxic algae. Finally, plastic can become loaded with pollutants that it transfers to our plates and into running water and that it transports to the Arctic and into the deepest ocean trenches, and even into the placenta of marine animals.
The oceans are polluted and marine ecosystems are suffering and sometimes disappearing, all around the globe. To save them, we must question production systems to operate differently. Everyone can act by boycotting certain actions and adopting new consumption habits to put pressure on decision-makers and manufacturers.
There is urgency, because even if we stopped consumption and therefore the discharge of plastic into the oceans today, this would not stop the development of plastic continents overnight.