Pollution

We dump more garbage into the ocean, than the tonnage of fish we take out. We can choose to stop doing that and that will be one less pollutant choking our seas.

Oil spills often come to mind when thinking about ocean pollution. In addition to the short-term impacts, severe long-term problems can also result. The Exxon Valdez, ran aground in Alaska in 1989, but the damage to marine life and waters of Prince William Sound can still be seen today. The Prestige oil tanker, which sank off the Spanish coast in 2002, was an environmental and economic disaster - destroying the local fishing industry and massively affecting local tourism after polluting more than 100 beaches in France and Spain.

But oil spills at sea only account for just a fraction of the pollution problem. Domestic sewage; industrial discharges; leakages from waste tips; urban and industrial run-off, accidents, spillage and explosions; sea dumping operations; oil production; mining; agriculture nutrients and pesticides; waste heat sources; and radioactive discharges are all sources of marine pollution. These land-based sources account for around 44% of all the pollutants in the oceans, while atmospheric toxins add an additional 33%. Ironically, only 12% of ocean pollution comes from activities at sea! In most cases, it is literally in our hands to prevent ocean pollution!

Creeping Dead Zones

“Creeping dead zones” are created by pollution from sewage discharge, agriculture and industrial pollution which stimulate "blooms" of algae in coastal waters. As these blooms die and decay they use up all the oxygen in the water, leaving it unable to support any living thing. It was NASA that coined the phrase, from watching the areas “creep” across the ocean from space.

Radiation

While the dumping of radioactive waste as sea has been banned since 1993, radiation contamination is still a problem for our oceans. Most recently fish on both sides of the Pacific Ocean have been found with high levels of radioactive contamination as a result of the Fukushima nuclear melt down in Japan.

The normal operation of nuclear power stations also pollute the sea, but far bigger point-sources of man-made radioactive elements in the sea are the nuclear fuel reprocessing plants at La Hague in France and at Sellafield in the UK. These discharges have resulted in the widespread contamination of living marine resources over a wide area; radioactive elements traceable to reprocessing can be found in seaweeds as far away as the West Greenland Coast and along the coast of Norway.

Toxic chemicals

Toxic pollution can travel through the atmosphere and can be deposited in colder climates, impacting communities and marine life far from its original source. Some of the most serious toxic chemicals are known as “persistent organic pollutants” (POPs). POPs can get into human and animal fat, causing cancers, hormone and immune system disruption and child development problems.

The Arctic Inuit populations are among the most heavily contaminated people on the planet and scientists also suspect that the chemicals have affected the reproduction of some polar bear populations in the Arctic. The blubber of dead whales in some areas is so highly contaminated that it would be classified as toxic waste.

Mining

Trace metal pollution from metal mining, production and processing industries can damage the health of marine plants and animals and render some seafood unfit for human consumption. The amount of mercury introduced to the environment by industrial activities is around four times the amount released through natural processes such as weathering and erosion.