Marine pollution is the harmful effect caused by the entry into the ocean of chemicals or particles. An associated problem is that many potentially toxic chemicals adhere to tiny particles which are then taken up by plankton. Most animal feeds contain high fish meal and fish oil content, toxins can be found a few weeks later in commonly consumed food items derived from livestock and animal husbandry such as meat, eggs, milk, butter and margarine.
One common path of entry by contaminants to the sea is rivers which are a source of mercury contamination of zooplankton (copepods) in the open ocean. It takes a few days before toxins are taken up by the plankton.
Ship pollution is the pollution of water by shipping. It is a problem that has been accelerating as trade has become increasingly globalized, posing an increasing threat to the world’s oceans and waterways as globalization continues. Because of increased traffic in ocean ports, pollution from ships also directly affects coastal areas. The pollution produced affects biodiversity, climate, food, and human health.
Ballast Water. When a larger vessel, such as a container ship or an oil tanker unloads cargo, sea-water is pumped into compartments in the hull. Similarly, when a larger vessel is being loaded it discharges sea-water from these compartments. The sea water is meant to help stabilize and balance a ship. Nevertheless, the discharge of ballast water only accounts for a small percentage of oil pollution in the marine environment.
Ships are also responsible for transporting harmful organisms in their ballast water. It is believed that one of the worst cases of a single invasive species causing harm to an ecosystem can be attributed to a seemingly harmless jellyfish.
In addition to introducing non native species into new environments, ballast and bilge discharge from ships can spread human pathogens and other harmful diseases and toxins potentially causing health issues for humans and marine life alike. Discharges into coastal waters along with other sources of marine pollution have the potential to be toxic to marine plants, animals, and microorganisms causing alterations such as changes in growth, disruption of hormone cycles, birth defects, suppression of the immune system, and disorders resulting in cancer, tumors, and genetic abnormalities or even death. They may also have the opposite affect upon some marine life stimulating growth and providing a source of food. Sources of seafood can become contaminated and unhealthy for consumption.
Oil Spills.Most commonly associated with ship pollution are oil spills. While less frequent than the pollution that occurs from daily operations, oil spills have devastating effects. While being toxic to marine life, polycyclic aromatic hydrocarbons (PAHs), the components in crude oil, are very difficult to clean up, and last for years in the sediment and marine environment.