Oil

Oil naturally seeps slowly from oil leaks in the ocean floor above natural oil deposits. At these sites which oil seep, microbes and ocean life that not only can put up with the oil leak, but even consume oil and metabolize it. However, there are not many of these ocean life forms but they are living proofs of how ocean life can exist in diverse environment.

Oil causes trouble when there is too much of it in the ocean. There are many oil spills examples such as the Exxon Valdez which we discussed, which caused much damage to the ocean and ocean life. There are more ocean life forms that do not adapt to oil spills environment. To those ocean life forms, oil spills are either lethal or causing long term damage to their health, reproductive systems, etc. Oil spills, although dramatic and causing sudden influx of oil into the ocean, they do not account for the greatest total input of oil into the ocean.

Toxic Metals

Several toxic metals occur naturally in ocean water. Although, they usually exist at subtoxic concentrations, they are often augmented by human activities to the point of being a problem. 

For example, metals associated with mining, industry, and waste incineration include mercury, cadmium, lead, zinc, copper, chromium, tin, and manganese. Sometimes, arsenic and selenium from other sources are also of concern.

Metals are also deposited on the ocean surface from the atmosphere. Natural sources of airborne metals include wind borne soil particles, volcanic eruptions, ocean salt spray, forest fires and biological aerosols. However, most of the naturally occurring toxic metals are small compared to the amount from human sources.