The deep ocean is subject to chemical pollution from a variety of sources. As well as oil pollution following disasters, the deep ocean receives chemical input from a wide range of sources including run-off from land, waste disposal, pollution from shipping, routine oil drilling and inadvertent dumping.
With increased human use of the open ocean for transport, mineral extraction and disposal, almost all of these sources of chemical pollution are increasing, resulting in greater and greater impact to the deep ocean and its ecosystems. Researching the potential impacts of pollution is of great importance so that the use of natural and chemical resources can be done in more sustainable ways.
Pollution in the deep sea is rarely more dramatic and immediate than that from a deep-water blow-out and the resulting oil spill. Pollution from less sensational sources is also causing widespread impact to deep-sea systems. Chemical contaminants, produced by humans, are increasingly reaching remote areas of the ocean and finding their way into the deep-sea food web. Many deep-sea animals, including fish and octopus, have measurable and sometimes high levels of toxic pollutants.
Life in the deep sea may be less resilient to its effects. Deep-sea organisms are typically subjected to a smaller range of environmental variation than shallow-water organisms and they live in areas that have not previously been affected by many chemical pollutants. The lifestyles of deep-sea organisms may be less conducive to dealing with chemical stress. Although marine pollution has a long history, until the twentieth century most scientists believed that the vast oceans had virtually unlimited ability to dilute and render pollution harmless. Increasing evidence to the contrary, including in the open ocean outside of regional jurisdiction, resulted in the formulation of significant international legislation to counter pollution. These laws have been effective at reducing some types of pollution that could reach the deep sea, particularly pollution from shipping, and regulating other polluting activities. However, despite regulation chemical pollution is becoming a more important stressor to deep-sea organisms and ecosystems.