How does garbage get into the ocean

The garbage in the oceans

Large accumulations of rubbish in the middle of the Pacific, tiny plastic particles in the ice of the Arctic, perished seabirds with litter in their stomachs: In recent years, media reports and research results have repeatedly raised concerns about the littering of the oceans.

The garbage can damage marine life and their habitats in the sea, especially because animals get entangled and strangled in it or swallow parts of garbage. Littering can also cause economic damage. Fishing and tourism, among others, are affected. At the same time, however, they are also one of the most important sources of input - that is, a large part of the waste comes from these areas.

There are now numerous initiatives to improve the situation. For example, the European Commission has presented plans for a European plastics strategy. It should help to reduce the entry of plastic waste into the oceans.

Private projects have also emerged that want to tackle the problem. This includes, for example, "The Ocean Cleanup". The initiative is developing a system of floating barriers to collect litter from the ocean surface. While the project receives a lot of support and attention, there are also criticisms and doubts about its effectiveness. (See section "Initiatives against pollution")

Garbage: Another threat to marine ecosystems

The oceans are the largest living space on earth. They cover around 70 percent of the earth's surface. The oceans provide the oxygen for every other breath. They are home to a rich biodiversity and provide people with raw materials and food. Around three billion people depend on protein intake from the sea. The oceans also serve as recreational areas. And they are used intensively by people, for example as transport routes.

But at the same time, various human activities are damaging the oceans. In addition to the input of garbage, this also includes overfishing, shipping, the input of pollutants and the acidification of seawater through the uptake of carbon dioxide from the air.

Marine litter can harm marine life in a number of ways. Larger pieces of plastic can become deadly traps for seabirds, sea turtles and other marine animals because they can get tangled and strangled in them. This applies in particular to lost or abandoned fishing gear and packaging material.

Seabirds and other animals can also swallow pieces of rubbish. Plastic parts are often found in the stomachs of dead seabirds. Fulmares found dead are regularly examined, presumably starving because of the garbage in their stomachs. Because the indigestible plastic parts lead to a constant feeling of satiety.

Experts fear that in this way not only individual animals are endangered, but also entire populations could now be affected. For example, some seal and whale populations become entangled in litter so frequently that the resulting mortality affects the population. Fulmars, on the other hand, peck their food from the surface of the sea and could ingest a particularly large amount of floating debris. In the German North Sea, 94 percent of all animals found have plastic parts in their stomachs.

So-called microplastic particles can also cause damage. They arise on the one hand when larger plastic parts break down into smaller and smaller pieces, and on the other hand through the use of products, for example through the washing of synthetic fibers from textiles or through tire wear. On the other hand, the particles are deliberately produced and used, for example, as an additive in cosmetics. Microplastic describes a size class of plastic particles - particles that are smaller than five millimeters. Often the particles are much smaller.

Litter in the ocean is ubiquitous

Plastic waste, including microplastics, is ubiquitous today, it has become a global problem. They have been found in extremely remote, uninhabited places and in the bodies of hundreds of different living things. Litter not only drifts on the surface of the sea, but also collects on the sea floor - even in the deep-sea trenches. Scientists also find microplastics in the sea ice of the Arctic. (See also Topic of the Week "Microplastics in Inland Waters" under Environment in Class)

Wherever there are large systems of currents in the oceans, garbage accumulates. Colloquially they are referred to as "garbage swirls". They are located far from the coast. Such accumulations of garbage can now be found in many regions of the seas, especially in the Indian Ocean, in the North and South Atlantic and in the North and South Pacific, but also in the Mediterranean.

How microplastics affect marine ecosystems is still unclear. Mussels and fish also take it in. In this way, the particles can get into the food chain. Humans might ingest them when eating seafood and when eating fish eaten with gastrointestinal tract. This includes, for example, sprats. It is still unclear how this could affect human health.

What is "marine litter" about?

The subject is attracting a great deal of attention, but much is still unclear. Numbers about the extent of the problem are often circulating in the media, but these are often not reliable. How much plastic actually ends up in the marine environment from which sources is largely unknown, according to the United Nations Environment Agency (UNEP).

Often there is general talk of "garbage in the sea" or "marine litter", in English-language publications "marine litter" or "marine debris"; plastic or plastic waste is often expressly named. The term plastic is used in specialist publications because it includes all artificially produced solid substances that consist of so-called polymers. These are long chains of molecules. Plastic are more colloquial terms. In contrast to plastic, for example, plastics also contain many adhesives. But even when it comes to the more general term garbage, plastic garbage makes up the overwhelming majority.

The Federal Environment Agency subsumes under marine litter or marine litter, all durable materials that have been manufactured by humans and that end up in the marine environment through throwing away or as abandoned goods. This definition is also used by UNEP and the group of experts that the EU has set up on this subject.

Available findings show that three quarters of marine litter consists of plastics, according to the Federal Environment Agency. A particular problem with plastics is that these materials take several centuries to break down and chemicals can be released that are toxic or hormonally effective. These chemicals include plasticizers, flame retardants and UV filter substances. Toxic chemicals that are already in the ocean can collect on the surface of microplastic particles. When marine life ingests plastics, these substances can enter the organism.

Microorganisms are not able to completely decompose all plastics. Many microplastic particles therefore remain permanently in the marine environment.

In the sea, on the seabed and on beaches, it has been observed worldwide that the number of microplastic particles is increasing. And it has been proven that marine life ingests the particles. For example, they were found in the droppings of harbor seals and seals in the Wadden Sea in Lower Saxony.

What is the situation like in the North Sea and the Baltic Sea?

The Federal Environment Agency has compiled facts and figures on marine litter in the North and Baltic Seas. These include the following findings for the North Sea:

  • With a share of 88.6 percent, plastics are mainly found on North Sea beaches.
  • On sections of beach in the German North Sea that are 100 meters long, there are an average of almost 400 pieces of garbage.
  • Seabirds have plastic in their stomachs, build the waste into their nests and get tangled in lines and cords.
  • Litter on the sea floor is common.

Where does the garbage come from?

The great pollution of the marine environment by plastic waste is a comparatively new problem. Because the production of plastics on a large scale did not begin until the 1950s. Since then, production has increased enormously. Around 322 million tons were produced worldwide in 2015. There are many different types of plastic. The four most common are PE (polyethylene), PET (polyethylene terephthalate), PP (polypropylene) and PVC (polyvinyl chloride).

Garbage finds its way into the marine environment in various ways. Part of it comes from the country. This waste is washed into the sea by streams and rivers or is blown away by the wind near the banks. Another part ends up deliberately or unintentionally from ships directly into the sea.

The sources from which the waste pollution originates and the proportion of the sources can vary from region to region. Most of the garbage pollution on German beaches in the North Sea comes from shipping and fishing. Investigations came to a share of 51 percent. Another important source in the entire North Atlantic area are leisure and tourism activities as well as the careless throwing of waste in public spaces. These get into the seas through rivers and canals, through industrial and sewage treatment plants, and with rainwater.

On the German Baltic Sea, tourism and leisure activities are the most important source of waste pollution on the beaches with a share of 50 percent, followed by discharges through sewage (25 percent), shipping (ten percent), offshore installations (eight percent) and fishing ( seven percent).

In general, around ten percent of the litter carried into the oceans can be traced back to fishing equipment that is lost in the ocean or left there. The environmental protection organization WWF estimates that in 2011 alone 5,500 to 10,000 set nets were lost in the Baltic Sea. The abandoned nets - also called "ghost nets" - represent a deadly danger for decades, especially for marine mammals, seabirds and fish. Although most nets sink to the seabed, they can remain erected there and sometimes continue to "fish" for long periods of time.

Where does the microplastic load come from?

Microplastics are not only created from larger plastic parts. It also gets directly into the sea, because many products contain microplastics as an additive. This includes peelings, for example. Even when washing clothes made of so-called fleece, small plastic fibers are released into the environment, because these particles are not completely retained in sewage treatment plants.

Depending on the material and shape, the waste behaves differently in the marine environment. Some float on the surface, others sink to the bottom, depending on the density and vegetation.

Around 40 percent of plastic production is used to manufacture packaging. Often for groceries. A large part make up water bottles and packaging for so-called convenience products or fast food. They are often found among the litter in the sea: eight out of ten finds on European beaches are single-use plastics.

Other sources are agricultural waste such as nets, foils, plant containers or pipes. There are also materials from the construction industry such as plastic sealant.

Another important source of plastic waste is tourism on the coasts. Very often, deliberate or careless throwing away is the reason why plastic objects and packaging end up in the marine environment.

A large part of the waste ends up directly in the sea, especially from shipping, fishing and aquaculture. This includes, for example, fishing equipment such as nets, ropes and boxes. In addition, some waste is dumped from ships in the sea, although this is prohibited.

Avoid and Recycle: Initiatives against the pollution of waste

A number of initiatives have emerged in recent years with the aim of reducing the pollution of the oceans. For example, the G20 group of the most important industrialized and emerging countries agreed on an action plan against marine litter. In addition, there are already international agreements including action plans against marine litter to protect the seas, for example OSPAR for the North Atlantic and the Baltic Sea and the Helsinki Agreement for the protection of the Baltic Sea.

Private projects have also emerged that have received a lot of support and attention. This includes, for example, "The Ocean Cleanup". The initiative is developing a system of floating barriers to collect litter from the ocean surface. While these and similar cleaning actions can help to raise awareness of the problem, there is also criticism and doubts about its effectiveness. Because only a fraction of the plastic waste can be collected with cleaning campaigns. Microplastics are not recorded. And cleaning systems can cause damage themselves, for example because marine life can get caught in them.

Marine litter is a consequence of societal developments, so policy initiatives to reduce litter cover different areas. On the one hand, it is about avoiding waste; and on the other hand to improve existing waste management systems and to recycle waste. (See also the background text under Environment in Class: "Avoid, Recycle, Dispose - Dealing with Waste")

Citizens can also do something about the littering of the seas in everyday life. Rubbish should always be disposed of properly - including the leftovers after a picnic on the beach. It is even better to avoid unnecessary plastic packaging altogether. Good alternatives to disposable packaging are, for example, reusable bottles or textile carrier bags.

In order to reduce the entry of microplastics into the environment, you should only use scrubs, shower gels and toothpastes that do not contain plastics such as polyethylene. In general, buying durable products also helps to avoid waste. This also saves valuable resources.

Anyone who wants to be active can also take part in voluntary clean-up campaigns on coasts, beaches and river banks.

Related Links

Federal Environment Agency: Garbage in the sea

Alfred Wegener Institute: Garbage in the Sea

Round table on marine litter: Status of implementation of measures to reduce the entry and occurrence of litter in the sea

United Nations Environmental Program (UNEP): Marine Plastic Debris & Microplastics (in English)

Download material