Chem 1103: Lecture 14: The Ocean’s Resources: Chap. 14 & The Human Presence
in the Ocean: Chap. 15
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This is the economics and policy part
Law of the sea
o Several treaties regarding ownership and exploitation of the marine resources
have been ratified in the last 50 years
 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 place the control of the sea bed, sea bed
resources, and water of the continental shelf under the country that
owns the nearest land
 The 1982 United Nations’ Draft Convention on the Law of the Sea
established:
 Territorial waters that extend seaward for 12 nautical miles
from the coast and are under the direct jurisdiction of the
coastal nation
 An exclusive economic zone (EEZ) that extends for 200
nautical miles offshore or to the edge of the continental shelf, if
that is farther, giving coastal nations the right to regulate
fishing, mineral resources, pollution, and research
 The right of vessels to free and innocent passage outside of the
territorial waters and through international straits that lie within
territorial waters
 That all private exploitation of mineral resources beyond the
exclusive economic zones must be approved by the United
Nations’ International Seabed Authority and that part of the
revenue from the resources will be shared with the developing
nations
 Exclusive economic zones contain about 40% of the ocean and the
high seas represent the remaining 60%
 The U.S. has the world’s largest EEZ because of the large areas
surrounding various island possessions and states
 The U.S.’s EEZ is 30% larger than the land area of the U.S.
Mineral Resources
o Petroleum is a complex mixture of hydrocarbons, combinations of hydrogen
and carbon with various amounts of nitrogen and metals
 Oil as it comes from the ground is called crude oil or petroleum
 The composition of the petroleum varies greatly depending
upon the geologic history of the material
 The smaller the size of the hydrocarbon molecule, the lighter
(less dense) the oil it is
 Oil can be separated into various densities by distillation
because oils of different densities evaporate at different
temperatures
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o 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
 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 was generated
 Pressure forced the oil and gas from the source rock into water-filled
porous and permeable strata above
 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 configurations of rock
layers have the potential to trap oil and gas. They do not
indicate if oil and gas are present
 Large reserves in ANWR and Mars (Gulf of Mexico), but only a
fraction of what America consumes
o Gas Hydrates refer to the unusual hydrocarbon deposits that consist of frozen
water molecules entrapping a single molecule of methane (natural gas)
 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
 Deposits on continental shelf of North Carolina are enormous, roughly
350x annual US energy consumption (annual ~ 6.6 billions gallons/yr)
o Sand and gravel are natural aggregates of unconsolidated sediment with grain
size greater than 0.0625 mm in diameter
 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 an 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
 Presently only 1% of sand and grave come from offshore
o Manganese nodules are composed of about 20-30% manganese, 10-20 % iron
oxide, 1.5% nickel, and less than 1 % copper, cobalt, zinc, and lead
 Locally the nodules can be very abundant, as on the subtropical sea
floor of the Pacific Ocean, where billions of kilograms occur
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Currently, there is no economical method of recovering the nodules
from the deep sea
o The sides of many seamounts and islands are enriched in cobalt between the
depths of 1 and 2.5 km
 Cobalt is a strategic metal used in making jet engines, and the U.S.
cannot produce sufficient cobalt to meet its needs
o Phosphorus is required for growth by all organisms
 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 release phosphorus compounds which precipitate as
phosphate nodules
 Nodules grow at the rate of about 1-10 mm /1000 yr
 World consumption of phosphate is about 150 million tons per year
and known supplies should last until 2050
Living Resources
o Marine finfish can be divided into the pelagic fish which live in the water
column and the groundfish which live on the sea floor
 Most of the ocean is sparsely populated because of low nutrient
availability
 Areas 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
 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
o Overfishing is removing a living resource form the sea faster than it can
replace itself, and if continued sufficiently long, the resource will collapse
 69% of fisheries are overfished
 Overfishing is possible today because:
 Technology has made it easier to locate large schools of fish
and direct fishing fleets to those locations
 Mismanagement of policies related to sustaining fish
populations
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 Fishermen resist quotas and misreport catches
 Maximum sustainable yield is the theoretical maximum amount of fish
that can be removed form a population without significantly
interfering with the population’s ability to renew itself
 The maximum sustainable yield is based upon biological
factors such as population dynamics, food webs and spawning
success, and the fishing effort required to produce a given
catch
 Problems with determining a maximum sustainable yield
include:
o Under-reporting the amount of fish caught
o Natural fluctuations of populations due to predation and
food supply
o The inherent difficulty in determining the size of fish
populations
o The unknown impact of discard fish (those returned to
the sea because they are too small or of poor quality) on
the population
 Politics frequently result in altering the scientifically
determined maximum sustainable yields to meet a political end
 It has been suggested that the concept of the maximum sustainable
yield be replace by the “precautionary principle” which is to avoid
anything that may damage or negatively impact a fishery
o Mariculture is marine agriculture or fish farming of finfish, shell fish, and
algae
 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
 Mussels, oyster, salmon
BREAK
 Pollution: What is it
o Pollution is the introduction by man, directly or indirectly, of substances or
energy into the environment, resulting in deleterious effects such as harm to
living resources, hazards to human health, hindrance of marine activities,
including fishing, impairing quality for use of sea water, an reduction of
amenities
 In studying pollution it is important to have a baseline from which to
measure man’s impact upon the environment because some of what is
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considered to be pollution may be occurring naturally and not caused
by man
 Pollution tends to be concentrated in three parts of the ocean
environment:
 Sea floor - accumulation on the bottom either by the settling
out of particles or being chemically attached to sediment
o This mainly affects the benthos
 Pycnocline – some pollution accumulates along the pycnocline
because it is too light to sink through the dense bottom water
o This is very common in estuaries
 Neuston layer – accumulation of pollution on the air-water
interface
o This mainly affects the plankton
 Pollutants are eventually broken down by various oceanographic and
biological processes
Hydrocarbons in the Sea
o Only a small fraction of the oil in the sea comes from major oil tanker
accidents
 About 32% if the oil in the sea comes from contaminated rivers
 Another 32% of the oil is released by tankers as they pump out their
bilges and from the incomplete burning of fuel in their engines and
general shipping traffic
 13% of the oil enters the sea as leakage from coastal refineries
 21% of the oil is from natural oil seeps, atmospheric fallout
o Once in the environment, an oil spill begins to be altered
 The oil slick naturally spreads outward and is additionally distributed
by waves and currents
 This greatly increases the surface area of the spill
 The light fraction of the oil evaporates, the soluble portion dissolves
into the water and the heavy insoluble fraction emulsifies (mixing of
one fluid into another without dissolving) and is vertically mixed in
the water column
 Emulsified oil forms globules which eventually become
floating tar balls that finally sink to the bottom or wash ashore
where they weather or are buried
 Microbes begin to degrade the petroleum into CO2
 Larger organisms ingest and metabolize some of the oil
o The rate at which the oil is dispersed and dissipated depends upon the
weather, composition of the crude, and the waves and currents
o All oil is toxic at all levels of the food chain, but the degree of damage
depends upon the type of petroleum and upon the specific habitat and
ecosystem
 In a coastal environment, an oil spill kills benthic, pelagic, and
nektonic organisms by poisoning or smothering
 On a muddy intertidal flat a spill will decimate the benthos, both plants
and animal
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On the open sea a spill does less damage because the volume of water
into which it mixes is much greater and the bottom is so deep it may
be unaffected
o There are several methods employed in attempting to clean a spill
 Floating booms are barriers placed around the spill to try and prevent it
from dispersing so that it can be removed more easily
 This is not effective if waves are large or winds and currents
are strong
 Chemical dispersants disperse the oil into the water
 Dispersants do not actually remove the oil and frequently are as
damaging or even more damaging to the environment than the
oil
 Burning the oil at the surface
 Oil is difficult to ignite and to keep burning. Additionally this
method creates air pollution which later settles onto the sea
 Skimming involves removing the surface water and recovering the oil
 Bioremediation involves stimulating the growth of microbes that feed
on the oil so that they decompose it
 If oil reaches the shore, it should be removed without disturbing the
substrate
Municipal and Industrial Effluents
o Each year humans produce over 20 billion tons of wastes, much of which is
disposed of in the ocean
 Most of the wastes come from farmland, cities, and industrial areas
and enter the sea by way of rivers
 Wastes tend to be concentrated in harbors, bays, and estuaries
 All bodies of water have a natural capacity to clean themselves of a
certain amount of pollution, but dense populations can produce so
much pollution that the self-cleaning capacity is exceeded
 As pollution enters the sea, it can be greatly diluted depending upon
the waves and currents
 Various pollutants behave differently depending upon their
temperature, density, and solubility
 As effluents are released, they form a contaminant plume which
increases in size with distance as the pollutant is diluted by
surrounding water
 Particulate matter will settle out at greater distances form the
source as particle size decreases
 Some of the material will be concentrated on the pycnocline
 Outward from the point of entry, the influence of the pollution
decreases and a series of gradational changes can be seen in the
bottom fauna
o At the source, the bottom will consist of a sludge and
there will be almost no infauna
o Farther from the source the fauna will consist of
dwarfed individuals
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o At a still greater distance, the fauna will be unusually
abundant and form dense masses
o At a great distance, the fauna will be unaffected by the
pollution and occur in normal density of normal size
individuals
 In estuaries, because of the reversing flow with the ebb and
flood tides, pollutants can be concentrated in the area where
released and not dispersed evenly
o Municipal and industrial wastes in the ocean can be divided into three general
categories: sewage, metals, and artificial biocides
 Bioaccumulation is the process whereby organisms retain and
concentrate a toxic material within their body
 Biomagnificatoin is the process whereby a toxic material increases in
concentration with each trophic level of a food chain
 It results from bioaccumulation at each trophic level
 Sewage consists of a messy sludge of organic and inorganic chemicals.
 Human wastes are a major component of sewage and consist of
organic matter, inorganic nutrients (mainly nitrates and
phosphates), and pathogens (disease-causing organisms such as
bacteria, viruses and parasites).
 If sufficient nutrients are released into the waters, it can
promote a phytoplankton bloom
o As dead phytoplankton sink to the bottom and
decompose, this creates an excessive biological oxygen
demand (BOD) that results in the water becoming
hypoxic or anoxic in a process called eutrophication
 The resulting low oxygen content will kill most organisms on
the bottom and in the affected water column
 As the herbivores are killed, there is less grazing
o More phytoplankton survive to reproduce and generate
additional organic matter that will create an even
greater BOD
 Eventually the entire food web can be decimated
 Eutrophication has been observed in lakes, embayments, and
even on sections of the continental shelf
 Heavy metal is a term loosely applied to a collection of elements such
as lead, mercury, cadmium, arsenic, and copper that normally occur in
trace amounts in the ocean but become toxic in larger dosages
 Heavy metals are normally added to the sea in small amounts
through weathering and volcanic activity
 Manufacturing and industrial processes can greatly increase the
amount o heavy metals released into the environment
 Mercury, especially in the form of methyl mercury is highly
poisonous because it is not biodegradable. It is stored in the
fatty tissue of an organism and damages the central nervous
system
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 Narragansett Bay, Fall river
 Artificial biocides are man-made toxic chemical compounds that do
not occur naturally
 Halogenated hydrocarbons or organochlorines are common
biocides and of these DDT (dichloro-diphenyl-trichloroethane) and PCB (polychlorinated biphenyls) are the most
widely distributed in the ocean
 These chemical compounds are not biodegradable and remain
in the environment for a long time
 They are adsorbed on the surface of silt grains, ingested by
deposit feeders and filter-feeders and stored in fatty tissues
 DDT is a highly toxic pesticide that is now banned in most of
the western world, but its use continues to increases in
underdeveloped countries
o Sprayed on crops and soil, much of it washes into rivers
 Some remains airborne, contaminating rain and
snow or settling out directly onto the ocean
surface
o It has been detected in the muds of the deep ocean and
in the ice of Antarctica
o Lens miles in diameter, > 1 m thick in LA region –
Santa Monica Bay due to Montrose Chemical in 60’s
and 70’s
 PCB is used in electrical equipment, paints, and adhesives and
is released into the environment by incineration and
unregulated disposal
o PCBs have been found throughout the ocean
environment
o Banned in 1979
o GE and the Hudson River – south of Albany
 Some shellfish beds closed in Narragansett Bay and NY
Harbor due to contamination
Ocean Dredging and Mining
o Dredging accounts for 80-90% of the material dumped at sea each year
 If the dredged material is clean, it presents no long-term environmental
problem
 If the material is dumped slowly enough, many benthic
organisms can work their way to the surface through the new
layer of sediment, but if too rapid, they are buried and killed
 If the dumped material is not the same as the original substrate,
a different group of organisms may colonize the area
 Clean dredgings can be used to replenish beaches that are
eroding
 Contaminated sediment represents an initial and long-term source of
pollution
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Dredging the contaminated sediment reintroduces pollution
into the water at the site of dredging
 Dumping the sediment releases pollution at the dumping site
 As the dumped sediment compacts, contaminated pore water
escapes and contaminates the water column
 Storms and currents which disturb the sediment will also reintroduce pollution
 So as to minimize reintroduction of he pollutants, contaminated
sediment is frequently covered by layers of clean sediment
o Mining of deep ocean deposits will most likely be accomplished with a
hydraulic pumping system that will vacuum water, sediment, and organisms
from the sea floor and bring them to the surface
 The majority of the organisms drawn into the system will be killed
 Large areas of the sea floor each day will be disrupted and stripped of
life
 Sediment released at the surface will create a massive sediment plume
as it sinks to the bottom
 If the plume sinks quickly, it will have little impact on
photosynthesis, but if remains suspended at the surface it could
inhibit productivity
 Rapidly subsiding sediment could bury organisms on the sea
floor and smother them
 Pollutants in the deep water could be introduced into the
surface water and contaminate the food chain
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