(Source: Marine Ecosystem: EMCBTAP-ENVIS N Marine Pollution: Causes and Consequences
Pollution of the world's oceans is quickly becoming a major problem on Earth. We know very little about the effect that pollution has on the oceans, but we continue to dispose off chemicals, sewage and garbage into it at an unprecedented rate. Most people likely do not even know what types of pollutants reach the oceans. There may be billions of people unconcerned about ocean pollution and hence this problem. Truly, the fish catch from the sea will tend to bio concentrate the pollutants to finally reach the humans.
Toxic Ocean Pollutants
Toxic pollutants in the ocean ecosystem have massive impacts on the plants and animals. Heavy metal poisoning (such as lead and mercury) from industrial effluents accumulate in the tissues of top predators such as whales and sharks (so do not hesitate to support ban of hunting whales and sharks but to the dislike of many others). Many a times such poisoning causes birth defects and damages nervous system. Dioxins from the pulp and paper bleaching process can cause genetic chromosomal problems in marine animals and may even cause cancer in humans. PCBs (polychlorinated biphenyls) typically cause reproduction problems in most marine organisms. PCBs usually come from older electrical equipment.
Poly-aromatic hydrocarbons (PAHs) are another source of marine toxic pollution and typically come from oil pollution and burning wood and coal. These PAHs are responsible for causing genetic chromosomal aberrations in many marine animals. Lastly, low-level radiation poisoning is also possible in the ocean environment. Though scientists know very little about how radiation affects marine organisms, it cannot be a good thing anyway. Some marine species such as a population of Beluga whales living in the St. Lawrence River area in Eastern Canada are in serious trouble because of marine toxic pollution. These Beluga whales are the victims of ocean pollution ranging from PCBs to heavy metals as well as other pollutants. However, toxic pollution is only the tip of the iceberg in terms of total ocean pollution.
The toxic pollution varies from PAHs heavy metal pollution from industrial effluent and fallout, PCB pollution and even possible low level radiation. No matter what we humans do, there is potential for serious pollution of the oceans.
Marine garbage disposal is another major form of ocean pollution. The world's oceans are a virtual dumping ground for trash. Sometimes the garbage includes junked out fishing nets, plastics, general household garbage and even like bulbs. In one case, an island 300 miles from the nearest inhabited island (and 3000+ miles from the nearest continent) had 950 pieces of garbage ranging from plastics to tin cans.
Garbage in the oceans is a serious issue as fish entangle themselves in fishing nets and animals sometimes eat trash products and die. There are numerous examples of dolphins, sharks and whales entangling themselves in fishing nets and dying from oxygen starvation. It is possible to clean garbage from the oceans if humanity quits using it as a garbage dump. Marine garbage can often enter into animal gut; plastic pop tab rings accidentally strangle animals and so forth. Controlling this form of pollution is important to maintain a healthy ocean ecosystem.
Even simple plastic bags can have large pollutive impacts within the ocean. In one case, a deceased sperm whale was found to have a party balloon blocking its digestive system. The whale died from inability to process its food and died of starvation. Plastics can also have negative impacts to boats if they accidentally plug water intake lines.
Sewage Disposal in Ocean
Sewage is yet another major source of marine pollution. Typically, the problem with sewage is that it causes massive nutrient loading in the ocean ecosystem. Nutrient loading triggers algal blooms in...