Learning Unit 6: Oceans and Coastal Issues

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Learning Outcomes Explain how the oceans are threatened by pollution Name the main sources of marine pollution Explain how coastal areas are affected by pollution Explain how mangroves are affected by human activities Explain the association between level of development and type of water pollution

Pages 126–135 and 142–145 in Middleton Pollution Pages 126–135 and 142–145 in Middleton Type Source Nutrients Runoff: sewage, forestry, agriculture, nitrogen oxides from power plants and cars Sediments Runoff: mining, forestry, agriculture, coastal mining and dredging Pathogens Sewage, livestock Persistent toxicants (PCBs, DDT, heavy metals) Industrial discharge, wastewater from cities, pesticides, seepage from landfills Oil Runoff: cars, heavy machinery, industries, shipping, accidents at sea and offshore oil drilling Plastics Fishing nets, cargo and cruise ships, beach litter, waste from the plastics industry and landfills

Pollution Pollution from ships Oil spills: Oil spills may occur from operations such as loading, discharging and bunkering in ports and oil terminals or from accidents. Tributyltin (TBT): TBT was used in anti-fouling paints on ship’s hulls. Dumping of waste Plastics and non-biodegradable materials

Environmental impacts Pollution Environmental impacts Oil Smothering of biodiversity. Damage to habitats Impaired ability to reproduce, grow and feed Bioaccumulation Tar balls on beaches Example: The Exxon Valdez oil spill in Alaska in 1989 which released 36,000 tons of oil resulted in the deaths of many seabirds, sea otters and bald eagles TBT Interference with hormonal systems in aquatic organisms such as whelks Disturbance of marine food chains Plastics Entanglement and suffocation of birds, turtles, seals, whales and dolphins These animals can also ingest plastics and non-biodegradable materials Discarded fishing gear continues to catch fish Floating debris can also transport and disperse invasive alien species Heavy metals Bioaccumulation in aquatic organisms, which may present a risk to humans and wildlife

Pollution Regulations Waste materials in the oceans are mainly regulated by the London Dumping Convention and the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) convention. Regional agreements under UNEP has made progress in addressing pollution problems along coasts. An example of a regional agreement is MED POL which monitors pollution in the Mediterranean Sea

Coastal eutrophication Pages 142–143 in Middleton Human activities that have increased the nutrient flow to coastal environments: Forest clearing Destruction of riverine swamps and wetlands Application of fertilizers Industrial use of nitrogen and phosphorus Detergents with phosphates Large livestock populations Fossil fuel combustion Acid rain (nitrogen release) Expansion of human populations in coastal areas

Coastal eutrophication Impacts of coastal eutrophication: Oxygen depletion Reduced diversity Increased toxic and phytoplankton blooms Negative changes in population structure and dynamics Algal blooms cause death of marine fish, mammals and invertebrates Algal blooms are also linked to the emergence of new disease pathogens