Marine Resources

1. Marine Resources

2. Who Owns the Seas? • 1609 Hugo Grotius urged for Mare Liberum or Freedom of the Sea • Assumed the seas’ resources (ie, fish) were an inexhaustible supply • 1702 Cornelius van Bynkershoek published De dominio maris • It outlined the concept of Territorial Sea – the coastal are that could be defended by cannons (3 nm)

3. Who Owns the Seas? • In response to new technology that allowed the mining of the sea floor… • 1958 - United Nations Conference on the Law of the Sea • Mineral mining rights on the continental shelf given to the neighboring nation • But the definition of continental shelf was poorly defined • The law still very ambiguous

4. Who Owns the Seas? • 1973-1982: a new Law of the Sea developed • Passed by 130 votes to 4 • US was against the law • 1993 the Treaty came into force • Although the US signed the treaty in 1994 it has not ratified it…. • Has not introduced and adopted the regulations etc required by the treaty

5. UN Convention on the Law Of the Sea (UNCLOS) • Coastal jurisdiction 12 n. miles • Exclusive Economic Zone (EEZ) 200 n. miles • Mineral & fishing rights • Pollution regulation responsibility • Free passage for shipping • International Seabed Authority – regulates seabed mining • Law of the Sea Tribunal – arbitrates disputes

6. EEZs of the world

7. EEZ of United States

8. 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 • 95 million tons of fish production are harvested directly from wild populations (salt and fresh water) • Another 35 million tons are harvested from aquaculture • 35 million people are directly employed in fishing • International trade in fish products was $US 55 billion which is greater than the individual gross domestic product of over 70% of the world’s nations The State of World Fisheries and Agriculture, FAO 2002

9. Fish recruitment Replenishes fish stocks and depends on: • Fertilization of eggs • Survival of fish larvae - less than 1% reach adulthood • Survival of juvenile fish • Mortality losses huge until fish matures • Death due to disease, predation, parasitism, pollution, lack of food etc….

10. Primary productivity and is very important in determining fish carrying capacity Nitrogen influx is the main limiting factor

11. Exploited ecosystems • Primarily 5 ecosystems involved • Non-tropical shelves • Tropical shelves • Upwelling • Coastal and coral systems • Open ocean

12. Proportion of fisheries in marine ecosystems

13. Increasing fisheries

15. Status of fish stocks • Fisheries exploitation • 47% are exploited to their maximum sustainable limits • 18% are over-exploited • 10% are depleted • Global catch estimates have declined by 0.66 million tons/year since 1988 • Marine fishes have shown an 83% reduction in historical breeding population size based on a study of 230 populations • Industrialized fisheries typically reduce community biomass by 80% within 15 years of exploitation • 55 species of marine fish have lost at least part of their geographical range • 3 species of marine fish have gone extinct over the past two centuries

16. Fishing down the food web • The mean trophic level of commercial species declined from 1950 to 1994 • Gradual transition from catching long-lived, high trophic level, fish-eating, benthic fish → short-lived, low trophic level invertebrates and plankton-eating pelagic fish • Large predatory fish biomass is only about 10% of pre-industrial levels(sharks, skates, rays, and marlin) • Effects greatest in the Northern Hemisphere • Serious consequences for ecosystems

17. 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 - 1993 Japan, Korea & Taiwan 30,000 miles of driftnet in 1 day in North Pacific -Now banned in many area or limited size (>2.5km)

18. Fisheries management Difficulties • Regulation of fishing vessels • Between 1970 & 1995 number of vessels x2 • In 1995 spent $124 billion to catch $70 billion of fish • Catch limits • difficulty of enforcement • uncertain quotas & population data • Many countries involved • Migrating fish • Human activities in one area impact another • Economic/political concerns (job losses etc.)

19. 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…

20. The Increase of Mariculture

21. Mariculture • Sewage pollution • Chemical treatments • Antibiotics • Escapes of non-native species • Parasites (sea lice) • Marine mammal conflicts • Shooting seals • Acoustic Harassment Devices & cetaceans

23. 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

24. Power from • Offshore winds • Currents – 2000 MW off Florida alone • Waves • Tides • Thermal energy (OTEC)

25. Current power

26. Wave power station

27. Potential Wave Power Hotspots

28. La Rance Tidal Power Plant

29. Potential Tidal Power Hotspots

30. 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.

31. OTEC system

32. 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

33. 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)

36. Amount of organic carbon in Earth reservoirs Other category includes peat, soil & living organisms

37. Geological resources • Sand and gravel • Deposits in S. Africa & Australia also contain diamonds • Deposits in SE Asia contain Tin • 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%)

39. Geological resources • 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 • Contain Mn & Fe (& Cu, Ni & Co)

40. Divergent and convergent plates and metallic sulfides

42. Chemical resources Freshwater from desalination • Distillation(water vapour boiled out of seawater - but a lot of heat needed) • Solar humidification/distillation (solar energy causes water evaporation – condensation collected) • 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)

44. Reverse osmosis

45. 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 and used to make: - sodium hydroxide (used in soap manufacture), - -sodium hypochlorite (disinfectants, bleaches, PVC) -sodium chlorate (herbicides, matches, fireworks) -hydrochloric acid (chemical processes & sealing pipes)

46. Pharmaceutical drugs • Antibiotics – (from deep ocean bacteria) • Anti-inflammatory –Pseudopterosins (from sea fans) • Anti-viral – Acyclovir (from sea sponge - HIV anti-virals from cyanobacteria & sponges • Anti-tumor – Eleutherobin(from soft coral) • Anti-cancer – Bryostatin 1(from bryozoans) = anti -leukemia – Deep ocean sediment bacteria= anti -colon, lung and breast cancers