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Published byAlaina Campbell Modified over 9 years ago
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UN Convention on the Law Of the Sea (UNCLOS) Coastal jurisdiction 12 n. miles Exclusive Economic Zone (EEZ) 200 n. miles 40% of ocean is under coastal control Mineral & fishing rights Pollution regulation responsibility Free passage for shipping International Seabed Authority – regulates seabed mining
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EEZs of the world
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EEZ of United States
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Fisheries Fish provide 15% of human protein consumption One billion people rely on fish as their main source of animal proteins Dependence on fish is higher in coastal areas Some small island nations depend on fish almost exclusively Another 35 million tons are harvested from aquaculture
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Nitrogen influx is the main limiting factor Primary productivity and is very important in determining fish carrying capacity
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Increasing fisheries
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By-catch Species caught incidentally Other fish species As much as ¼ the total catch 20 - 40,000,000 tons of by-catch a year Turtles Seabirds (e.g. Albatrosses) Dolphins Tuna fishery & dolphins Driftnets
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Mariculture 37% of total world fishery Fish Crustaceans Shrimp and prawn most successful Bivalves (e.g. oysters) Also successful Algae Mainly seaweeds BUT there are problems…
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Mariculture Sewage pollution Chemical treatments Antibiotics Escapes of non-native species Parasites (sea lice) Marine mammal conflicts Shooting seals Acoustic Harassment Devices & cetaceans
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Energy from oceans Advantages Relatively non-polluting Huge potential Amount of energy available greater than fossil fuels or uranium Renewable Largely reliant on heat stored in oceans & atmosphere – not directly from sun Readily available along coasts
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Power from Offshore winds Currents – 2000 MW off Florida alone Waves Tides – only one being successfully exploited Thermal energy (OTEC)
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Current power
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Wave power station
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Potential Wave Power Hotspots
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La Rance Tidal Power Plant
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Potential Tidal Power Hotspots
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Ocean Thermal Energy Conversion (OTEC) Warm water near the surface heats a fluid (e.g. liquid propane or ammonia) Liquid turns to gas – increase volume of gas turns a turbine Cold water from the deep ocean cools down the fluid Fluid become a liquid etc. etc.
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OTEC system
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Geological Resources Petroleum 95% of the economic value of non-living marine resources Offshore about 30% of total world production (started in 1930s) Likely to increase in future Esp. Arctic, Asia, W. Africa & Brazil Deeper ocean to be exploited
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Geological Resources Gas Hydrates Composed of water and natural gas (e.g. Methane hydrate) Occur under permafrost on land and under ocean floor High pressure and cold temperatures trap gas in water crystal lattice Created when bacteria breakdown organic matter in seabed sediments (creating methane & some ethane & propane)
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Amount of organic carbon in Earth reservoirs Other category includes peat, soil & living organisms
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Sand and gravel 2 nd to petroleum Phosphorite (sedimentary rock) Found at depths of <300m – usually associated with upwellings Not currently mined but could be used to produce phosphate fertilizer Some muds up to 18% content - also nodules (25%) Geological Resources
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Metal sulfides Rich deposits of Cu, Pb, Zn & Ag Found near plate boundaries Metal enriched hot water exiting boundary meets cold seal water – sulfides precipitate Manganese nodules Discovered in 1872, scattered in deep ocean Contain Mn & Fe (& Cu, Ni & Co) Geological Resources
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Divergent and convergent plates and metallic sulfides
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Chemical Resources Freshwater from desalination Distillation (water vapor boiled out of seawater - but a lot of heat needed) Electrolysis ( Na + & Cl - are removed from water by means of charged electrodes) Reverse osmosis (water pumped in at high pressure forcing water through a semi-permeable membrane - which holds back salts etc) Freeze separation (ice 70% lower salinity than seawater)
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Reverse osmosis
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Chemical Resources Evaporative salts – salts remaining when water content of seawater evaporates Gypsum – used in plaster of Paris and gypsum board (sheet rock) Halite – table salt
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Pharmaceutical drugs Antibiotics Anti-inflammatory Anti-viral Anti-tumor Anti-cancer
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