How Are the Seas Polluted? PDF

## How are the Seas Polluted? ### Cause + Elaboration 1. **Improper disposal of sewage** Untreated or poorly treated sewage from farms and homes. The excessive nutrients in sewage may cause algal blooms in coastal regions. They turn to **dead zones**, where most forms of life cannot surviv...

## How are the Seas Polluted? ### Cause + Elaboration 1. **Improper disposal of sewage** Untreated or poorly treated sewage from farms and homes. The excessive nutrients in sewage may cause algal blooms in coastal regions. They turn to **dead zones**, where most forms of life cannot survive based on the following process: - **Intensive farming** - **Excessive chemical fertilizer** being washed into the sea - **Increasing nutrient in the sea (Eutrophication)** - **Explosive growth of algae (algal bloom)** - **Sunlight blocked** - **Competition for oxygen among algae** - **Respiration of sea plants (No oxygen photosynthesis)** - **Death of plants/ algae** - **Decomposed by bacteria** - **Use up the oxygen** - **Fishes die in dead zone** 2. **Oil Spill** Oil tanker crashes and oil drilling accidents cause large oil spills. Oil from land is washed into the seas through sewers and rivers. 3. **Disposal of solid waste** Different types of solid waste are brought from the land to the oceans by sewers and rivers. Plastics are one of the major solid wastes found in the oceans. 4. **Improper disposal of radioactive material** The dumping of radioactive waste and conduction of nuclear tests in the oceans increase the risk of radiation pollution. Accidents of coastal nuclear power stations may cause disastrous damage. ### Impacts of Marine Pollution #### Impact + Elaboration 1. **Threatening marine life** Solid waste, especially plastics, may trap or choke marine animals. Seawater polluted with heavy metals, oil and other chemicals can poison marine life and destroy marine habitats. 2. **Food web contamination** Heavy metals and toxic chemicals are absorbed by marine life and build up along the food chain and spread to food web. When people consume the contaminated seafood, they may become sick. ### Socio-economic Impacts #### Impact + Elaboration 1. **Decline in tourism** 2. **Health Risk** Marine pollution increases the risk of food poisoning. The government expenditure on medical services will increase. 3. **Loss of recreational activities** Recreational activities will be suspended when the coastal areas are polluted.