Pollution

Marine pollution, such as oil spills, disposed plastics and waste products, also poses a genuine threat to the health of the oceans and their ecosystems. Biological pollution in the form of introduced species and nutrient pollution is also of particular concern to marine biologists.   Introduced species, such as certain forms of algae, can take over large areas of the sea bed, growing over and smothering marine life living close to the ocean’s floor. Excessive amounts of nutrients can be caused naturally following storms and water mixing from currents, however the pollution that runs off the land into water systems and eventually into the ocean is having the greatest affect, mainly in coastal areas. During this process, oxygen levels are altered and impact directly on marine plants and sea grasses, causing them to die or decay. This in turn uses up oxygen and leads to low levels of dissolved oxygen in the water further destroying marine animals such as crabs, oysters and fish.