The Ocean Resources

1
The Ocean Resources
2
Several treaties regarding ownership and
exploitation of the marine resources have been
ratified in the last fifty years.
14-1
Law of the Sea

• President Truman extended U.S. control of the
  marine resources from the shoreline to a depth of
  100 fathoms (183 m).
• The 1958 and 1960 Geneva Conventions on the Law
  of the Sea resulted in a treaty that placed the
  control of the sea bed, sea bed resources and
  water of the continental shelf under the country
  that owns the nearest land.

3
14-1
Law of the Sea

• The 1982 United Nations Draft Convention on the
  Law of the Sea established Territorial waters and
  An Exclusive Economic Zone (EEZ) that extends for
  200 nautical miles offshore or to the edge of the
  continental shelf, if that is farther.
• Exclusive economic zones contain about 40 of the
  ocean and the high seas represent the remaining
  60.

4
Petroleum, oil and gas are hydrocarbons derived
from sedimentary rocks which were deposited in
quiet, productive regions with anoxic bottom
waters in which the remains of phytoplankton
accumulated.
14-2
Mineral Resources

• Deep burial resulting in high temperature and
  pressure converted the organic remains into
  hydrocarbons.
• Initially oil, but at higher temperatures and
  pressures, methane (CH4) natural gas were
  generated.
• Pressure forced the oil and gas from the source
  rock into water-filled porous and permeable
  strata above.

5
14-2
Mineral Resources

• Because oil and gas are less dense than water,
  they migrated upwards until their path was
  blocked by an impermeable layer.
• Oil and gas accumulated, forming a large deposit
  within the pores of the rock, usually sandstone.
• Location of possible accumulations of oil and gas
  can be determined using seismic reflection and
  refraction methods to determine the configuration
  of rock layers.
• These methods only indicate if the configuration
  of rock layers have the potential to trap oil and
  gas. They do not indicate if oil and gas are
  present.

6
Gas Hydrates refer to the unusual hydrocarbon
deposits that consist of frozen water molecules
entrapping a single molecule of methane (natural
gas).
14-2
Mineral Resources

• Gas hydrates occur in polar sediments and in
  deposits of the continental slope between the
  depths of 300 and 500 m where cold water is in
  contact with the sea floor.
• These deposits contain incredibly large amounts
  of gas, but currently there is no economical
  method for its recovery.

7
Sand and gravel are natural aggregates of
unconsolidated sediment with grain size greater
than 0.0625 mm in diameter.
14-2
Mineral Resources

• Sand and gravel accumulate in high energy
  environments where strong currents and/or waves
  currently prevail and occur as relict sediments
  across the continental shelf from when sea level
  was lower.
• These materials are used for construction of
  roads and buildings and to replenish beaches
  which are undergoing erosion.
• Mining sand and gravel deposits from the shelf
  threatens both the benthic and pelagic
  communities and introduces large amounts of
  material into suspension.

8
Manganese nodules are composed of about 20-30
manganese, 10-20 iron oxide, 1.5 nickel and
less than 1 cobalt, copper, zinc and lead.
14-2
Mineral Resources

• Locally, the nodules can be very abundant, as on
  the subtropical sea floor of the Pacific Ocean,
  where billions of kilograms occur.
• Currently, there is no economical method of
  recovering the nodules from the deep sea.

9
The sides of many seamounts and islands are
enriched in cobalt between the depths of 1 and
2.5 km.
14-2
Mineral Resources

• Cobalt is a strategic metal used in making jet
  engines and the U.S. can not produce sufficient
  cobalt to meet its needs.

10
Phosphorus is required for growth by all
organisms.
14-2
Mineral Resources

• Phosphate deposits generally form on submarine
  terraces where coastal upwelling generates high
  productivity.
• Organic wastes and remains accumulate in the
  sediment and as they decay, they releases
  phosphorus compounds which precipitate as
  phosphate nodules.
• Nodules grow at the rate of about 1 - 10mm/1000
  years.
• World consumption of phosphate is about 150
  million tons per year and known supplies should
  last until 2050.

11
Marine finfish can be divided into the pelagic
fish which live in the water column and
groundfish which live on the sea floor.
14-3
Living Resources

• Most of the ocean is sparsely populated because
  of low nutrient availability.
• Area of major fish production are the coastal
  waters and regions of upwelling.
• Because they are economic to capture, major
  commercial fishes are those which form large
  schools.
• The fishing industry uses sonar, scouting
  vessels, airplanes and satellites to locate
  schools and then deploy the fishing fleets to
  those areas.

12
14-3
Living Resources

• Drift nets are controversial because they capture
  everything too large to pass through the mesh of
  the net and needlessly kill many organisms.
• The 1989 United Nations Convention for the
  Prohibition of Long Drift Nets prohibited drift
  nets longer than 2.5 km, but compliance is
  largely voluntary and impossible to enforce on
  the open sea.
• World ocean fish production appears to have
  leveled at between 80 and 90 million tons
  annually.
• Currently, the expense incurred in fishing
  exceeds the profit from the sale of the fish and
  fishing industries only survive through
  government subsidy.

13
Mariculture is marine agriculture or fish farming
of finfish, shell fish and algae.
14-3
Living Resources

• Mariculture requires raising the organisms under
  favorable conditions until they are large enough
  to be harvested for food.
• Currently, about one out of every four fish
  consumed spent part of its life in mariculture
  and for some organisms the percentage supplied by
  mariculture is even larger.
• For mariculture to be economically viable the
  species must be
• Marketable.
• Inexpensive to grow.
• Trophically efficient.
• At marketable size within 1 to 2 years.
• Disease resistant.