Marine litter and the consequences
The worst thing is that most of the garbage is not even visible, as only 15% of the garbage floats on the surface of the water and just as much washes up on the shore. The remaining 70 % sinks to the seabed. According to estimates, there could be more plastic items than fish in the sea by 2050.
Plastic in the seaUp to 75% of marine litter consists of plastic, which only breaks down very slowly into smaller and smaller pieces, known as microplastics. This happens in the sea due to the effects of salt water, sun and friction. For example, a plastic bag takes up to 20 years, a polystyrene cup around 50 years and a PET bottle a whole 450 years to completely disintegrate.
Over 150 million tons of plastic now pollute our oceans. Every year, 4.8-12.7 million tons of plastic are added.
Microplastics and POPs are harmful to healthMicroplastics are very dangerous. As they decompose, plastics can release toxic and hormonally active additives such as plasticizers into the sea and the organisms living in it, which then ingest them. In addition, large quantities of persistent organic pollutants (POPs) from the water can bind to the microplastic particles and thus also enter the bodies of many marine organisms. These pollutants fall into the highest category of hazardous substances. These include PCBs (polychlorinated biphenyls), for example. These are non-degradable and therefore accumulate in the tissue of living organisms, especially in oily fish. As fatty fish is also processed into fish oil and meal, so-called farm animals are also fed with it. When consumed, the harmful substances enter the human body. These can damage the endocrine system and lead to infertility, cause cancer and disrupt the immune system and child development. The exact effects of microplastics on health have not yet been clarified in detail.
How does the waste get into the sea?Pollution of the oceans is one of the most obvious effects of human activity. Litter primarily enters the sea from the land via rivers. Around 80% of litter ends up in our oceans in this way. This includes pollutants such as pesticides, artificial fertilizers, cleaning agents, wastewater and vast quantities of plastic particles and other solid bodies. The remaining 20 % ends up in the ocean via ships, particularly oil tankers. Around 675 tons of waste end up in the sea every hour, half of which is plastic waste. This is particularly the case in countries where the collection and recycling of waste does not work properly, e.g. in countries in South East Asia.
There is now so much waste that five gigantic floating garbage patches have formed in the center of the oceans. The best known is the "Great Pacific Garbage Patch" in the North Pacific, which is now estimated to have reached an area the size of Central Europe.
"Creeping death zones" due to low oxygen contentOn the coasts, nutrients from wastewater and agriculture can potentially trigger a dangerous algal bloom. When the algae die off, they consume the oxygen bound in the water. In some areas, such as parts of the Baltic Sea and the Gulf of Mexico, the oxygen content of the water is so low that life in the water is no longer possible. Fish and other sea creatures die. In this case, we speak of creeping dead zones (CDZ).
But it's not just the waste problem that threatens our oceans. Overfishing, acidification and global warming are also causing problems for the oceans. The population of large ocean fish is said to have declined by almost 90% since the start of industrial fishing. Many fish are threatened with extinction. You can also read more about overfishing in this article: Omega-3 from algae - the better choice for the oceans.