The main sources of marine
pollution affecting, damaging or even destroying the marine ecosystem are:
- Agricultural waste: biocides, chemicals used to remove various species considered pests, such as insecticides (eliminate insects), herbicides (to prevent the development of weeds), fungicides (to prevent fungus growth), nematicides (eliminating nematodes, a kind of worms) and many others, which do not biodegrade or break down easily, becoming remaining pollutants affecting the environment for long.
- The residues of fertilizers, such as nitrites, nitrates, phosphates and many others, into the sea through rivers, excessively enriched water, producing an overabundance of algae and a decrease in the oxygen concentration.
- Urban waste: sewage systems dump domestic waste water into the sea. These contain organic waste, such as food waste, fecal waste that may contain harmful bacteria, toxic chemicals, such as chlorine, detergents or other elements used to disinfect bathrooms and kitchens, or elements difficult to decompose, like oil.
- Industrial wastes much of the waste from industrial processes end up in the sea. These may be food remains relatively biodegradable, but they may also contain heavy metals and a number of more or less dangerous chemical substances.
- Radioactive waste: through leaks of radioactive material from nuclear power plants or ships that transport such materials offshore and nuclear waste products for testing of pumps, such as those made by France at Mururoa atoll, located in the South Pacific.
- Waste oil: refineries tend to be on the coast, near productive estuaries, so often their waste into the ocean. Offshore oil spill boats, either by accidental loss, as happened when a boat has been injured, or intentionally. For example, by washing their ponds in the ocean. The platforms that extract oil and gas from the seabed and motor oil boats and small vessels also contribute to pollution of the marine ecosystem.
- Garbage: unfortunately, it is quite common that men throw all kinds of waste and waste directly into the sea, on the beaches and coastal borders. Many of these items are not biodegradable or are very long term.
- Air pollution: many chemical elements contained in the smog also reach the sea, becoming a major pollution source. These substances are precipitated by rain and carried by rivers to the sea.
- Minerals: as a result of mining, many wastes (copper, mercury, cadmium, nickel, zinc) are discarded directly into rivers or the sea.
- Pollution is highest at the mouths of rivers, bays and harbors, as it is in those areas where sewers and rivers with different types of waste arrive. Therefore, coastal waters are dirtier than the open sea, because the surface of the shelf is easier accumulation of pollutants, because the depth is much lower.