Marine

2.  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 area that
could be defended by cannons (3 nm)
Who Owns the Seas?

3.  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
Who Owns the Seas?

4.  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
Who Owns the Seas?

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

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.  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
Status of fish stocks

16.  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
Fishing down the food web

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.  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%)
Geological resources

39.  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)
Geological resources

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