The Effects of Sea Pollution on the Marine Environment
When oil is discharged into the sea the sea surface slick is carried towards the shore by the waves, ending up on the shoreline. Here the seabirds and mammals get their fur and feathers coated with oil and this destroys their body heat insulation, leading to death. Oil ingestion can also cause long term illness, eventually leading to death and species extinction.
Many species of marine surface larvae are also decimated by oil floating on the sea surface, as the fish, birds and mammals feed on this they will have to migrate to other feeding grounds.
When oil disperses, it also sinks to the sea floor breaking up into smaller globules on the way down that fish ingest this and die. The oil then lies on the sea bed until absorbed by the silt/sand, only to re-emerge at a later date.
Finally reefs and corals, mangroves, and wetlands are particularly susceptible to oil pollution, due to the very nature of their construction and location, absorbing the oil and destroying the ecosystem.
Ships Ballast Discharge
When ships ballast their tanks with seawater, the seawater contains species local to that ecosystem. When the ship deballasts at a foreign port, it discharges these now alien species, often with disastrous consequences to the local ecosystem.
Land Based Pollutant Effects
Discharges from industry such as chemical plants, oil refineries, and numerous types of metal ore extraction sites can contain poison in the form of heavy metals- mainly mercury and lead.
These are ingested by the fish and gradually build up as smaller fish are eaten by the larger ones until, at the top end, sharks, tuna and swordfish will contain significant amounts of heavy metals. When these fish are consumed by us humans, we can develop serious medical conditions.
Many other chemicals that are discharged into the sea from industry cause marine pollution, leading to degradation in marine life, and again if they are consumed by humans can cause cancer and other serious medical conditions.
Run-off from land can contain fertilizers high in nitrogen and phosphates that promote eutrophication- excessive plant growth that reduces the supply of oxygen to the sea. This is more prevalent in estuaries where rivers have carried fertilizers into the sea; here it destroys the natural habitat, fish and shellfish along with recreational facilities.
Seethe sea: Pollution Threat
Science daily: Sea pollution Monitoring
Offshore environment: Oil Pollution
gpa.unep: Oil Pollution
InfrastructureGov: Maritime Environment Law