|Themes > Science > Earth Sciences > Oceanography > Ocean Pollution > Water Pollution in the World's Oceans|
As far as "Which do oil spills hurt more, animals or the ocean?", I guess I would say that spilled oil mostly affects marine life, rather than the ocean per se, as oil is mostly composed of insoluble organic compounds. On the surface, where the lighter components of oil in an oil spill will float, sea birds, phytoplankton (plants) and fishes are all affected during an oil spill. The oil physically fouls birds feathers (making it difficult for them to fly), clogs fishes' gills (making it difficult for them to breath) and blocks out the sunlight (making it difficult for marine plants to photosynthesize). When oil sinks to the bottom of the ocean, it again fouls organisms living in or on the sediments.
The average level of pollution in the world yearly from oil spills is hard to estimate, since oil spills are episodic in nature. It is a small percentage of the total petroleum transported from place to place on a yearly basis, however. A more common source of oil pollution is from the dumping of "drilling mud" on the sea floor near offshore oil wells. It has been estimated that 90% of the oil hydrocarbons in the North Sea are from this source. Other sources of "oil" pollution include refinery wastes and municipal wastes/ urban stream runoff.
Pollution can only really be stopped if each individual takes the time and expends the energy to be careful. Many polluting events are accidents, because people are sometimes lazy or sloppy when they work; other spills are on purpose,simply because companies don't want to spend money to do the job cleanly; still other pollution comes from regular people going about their daily routine, unaware that their automobile, airconditioner, refigerator, and oven all pollute the world a little bit.
To stop pollution, we must all do our part to try to be clean in our daily activities, to only buy products from ecologically-responsible companies, and to convince our law makers that we need stronger laws to not only make pollution illegal but greater enforcement of those laws, particularly in areas under international jurisdiction.
As far as plastics in the oceans are concerned, they are inert substances. They "pollute" the world's waterways in physical, rather than chemical ways. Most plastics typically float and many marine oganisms (fish, birds, etc...) confuse them for food and injest them, or simply get tangled up in them, and die. Plastics decompose very slowly, so each bit we produce and don't recycle contributes to the enormous quantity of plastics in the trash humans produce daily, some of which makes it out into the environment. Also, the production of plastics involves many noxious and polluting chemicals.
The ocean can get contaminated with nuclear waste by illegal dumping, atomic bomb tests (such as the ones the French government conducted in 1995 on Murarora atoll in the southern Pacific), or accidents aboard nuclear powered vessels or at nuclear reactors near coastlines. Although environmentally "non-ideal", the damage done by radioactive spills at sea is probably far less than damage done by equivalent spills on land, or by other forms of chemical and physical pollutants spilled at sea. This is because the soluble components of radioactive waste are disperesed into the ocean at large over relatively short time periods. The insoluble wastes will fall to the sea bed and, much like the case for oil spills, locally affect marine life in that location.