Ocean Uses and Human Impacts
Outline
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Marine Resources
Mariculture
Drugs
Marine pollution
Invasive species
Climate Change
Classes of Marine Resources
Physical resources
Mineral deposits, petroleum, natural gas, freshwater
Biological resources
Plants and animals, microbes
Marine energy resources
Energy from heat or motion of water
Non-extractive resources
Transportation, recreation, waste disposal
Petroleum and Natural Gas
Oil and gas are often found together beneath impermeable
caprock. Drilling for oil offshore requires specialized
equipment and is more costly than drilling on land.
Gulf of Mexico Oil Spill
5000 barrels/day  15000 barrels/day
Containment (booms), skimming,
dispersants, Domes, caps, siphons, new well
Full recovery will take many years
Salts and Minerals
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Magnesium
Sodium chloride
Manganese nodules
Phosphorite
Metallic sulfides and muds
Fresh Water
• Only 0.071% of Earth’s
water is liquid, fresh,
and available at the
surface for humans
• More than 1500
desalination plants
worldwide
• 3.5 billion gallons/day,
and rising!
Marine Energy – Wave Motion
Energy generated by waves (Dr Brekken) and tides
Biological Resources
Major types of commercially harvested fishes,
crustaceans, and mollusks
Biological Resources
World Commercial Catch of Marine
Fishes, Crustaceans, and Mollusks, by
Species Group, 1997
Millions of
Metric
Tons
Species Group
Herring, sardines, anchovies
21.5
Jacks, mullets, sauries
10.9
Mollusks
15.5
Cods, hakes, haddocks
10.2
Redfish, basses, conger
eels
7.4
Crustaceans
6.8
Tunas, bonitos, billfishes
4.8
Mackerel, snooks, cutlass
fishes
5.2
Flounders, halibuts, soles
1.0
Miscellaneous Marine
Fishes
17.5
Total for all sources
100.8
Table from Garrison, 4ed
Fisheries
Typical evolution
of ocean fisheries
Fisheries Exploitation
Concept of a Stock
A population of a species of fish that is
reproductively isolated in space and
time
Each stock must be treated separately in
assessing fishing impacts
Stock Equilibrium
Growth
Recruitment
Stock Size
(Exploitable
Biomass)
Mortality
Fishing
Removals
These four factors must remain in balance for
stock equilibrium to be achieved
Maximum Sustainable Yield
CPUE
Catch
Per
Unit
Effort
Community Effects
 Altered trophic webs
Keystone species may
be removed or
reduced
 Fishing down food webs
The mean trophic level
of a marine
ecosystem is reduced
So, what can YOU do?
 Support sustainable fisheries with your $$
 See: MBARI Seafood Watch wallet card
 http://www.mbayaq.org/cr/seafoodwatch.asp
 See also:
 http://www.seafoodinfocenter.org/search.html
 http://www.seafoodchoices.net/
Potential
Harmful
Impacts of
Mariculture
 Escape of nonnative species
 Herbicides
 Disease
tolerance and
spread
 Nutrient
enrichment ->
eutrophication
Drugs
• Researchers estimate that 10% of
marine species may contain useful
medical compounds
• Acyclovir, the first antiviral
compound approved for humans, is
derived from a Caribbean Sea sponge
• Pseudopterosins, a class of antiinflammatory drugs, is derived from
marine species
• Bone substitute for speeding
regrowth of bone grafts is available
from Corals. Coral skeletal structure
is remarkably similar to human bone
Marine Pollution - DDT
 Levels of organic
pollutants may be
low, but biological
amplification
concentrates harmful
toxins
 The concentration of
DDT in the fatty
tissues of organisms
was amplified up to
10 million times in a
food chain off the
coast of New Jersey
Marine Pollution – HABs and
Anoxia
Invasive Species
 Introduced species crowd out
native species, alter habitats,
and impose economic burdens
on coastal communities.
 The rate of marine introductions
has risen exponentially over the
past 200 years and shows no
sign of leveling off.
 More than 175 species of
introduced marine invertebrates,
fish, algae, and higher plants live
in San Francisco Bay.
 http://www.invasivespecies.gov/
Invasive Species – Zebra Mussel
Recent US Bioinvasions
http://www.pewoceans.org/reports/introduced_species.pdf
Global Warming
Arctic Ocean and Sea Ice
Mountain Glacier Retreat
1858
2001
“The Snows of
Kilimanjaro”??
Antarctic Ice Sheet
Antarctic Ice Sheet
EAIS
WAIS
Both Greenland Ice Sheet and
West Antarctic Ice Sheet = 6
m global sea level.
25% of U.S. population lives
within 10 m of sea level.
WAIS
People at risk
 Country
population
Bangladesh 115 million
Egypt
55 million
Indonesia 185 million
Maldives
0.2 million
Pakistan
110 million
annual income
$160
$710
$450
$300
$350
4 Overarching Conclusions:
Climate Change is coming at us a lot faster than we
thought. We are not going to get through this crisis
without casualties – if at all
All the stuff about changing light bulbs and driving hydrids
is practically irrelevant to wholesale de-carbonization by
2050. Over-Population and “carrying capacity” of Earth.
We need C-free energy and C-sequestration
It is not realistic to reach the 2050 goal because we have
started too late, so we need geo-engineering solutions to
buy time
The political environment becomes increasingly more
unstable with increasing Temperature; this will be the
next military challenge after the Middle East
Solutions are Clear and Reachable
No fine-tuning yet, but we know how to keep <2°C, and so
prevent going beyond 450-500 ppm CO2 world
We are acting to preserve one particular climate state
among many potential ones within the “deep glacial” to
“greenhouse extinction” spectrum
We have only fragmentary knowledge of how the climate
system works so we must learn much more about it
Strategy for the Short Term
Keep the T’s under control to prevent “runaway”
greenhouse
Avoid loss of prime agricultural land, major population
dislocations, spread of disease/famine, slowdown of
thermohaline circulation
Maintain high-energy technology/industry but move to
completely de-carbonize, replace decimated forests,
create large MPAs
Reduce population, produce more protein, less sugar
“Final Exam” Metaphor
Fossil fuels have provided the means to develop the
western world’s high standard of living: longer lives,
security and leisure, democratic political states,
universal education, community welfare, high levels of
equality, and international institutions for peace and
prosperity.
However, this is a “one time deal” for building the present
industrial state!!
We now have to manage, in your lifetimes, the transition to
a new technology-based industrial state:
mostly in the next 20 years
completely de-carbonize by 2050
hold the line on 2°C increase, and return to 350ppm
“Final Exam” Metaphor
We barely survived the mid-term exam (cold war and
nuclear annihilation)
Knowledge, self restraint, resolve and cooperation are
required
We have some chance of “passing”, and how interesting the
long future that stretches ahead will be, if we do pass!
Challenge for Your Generation
 1870-1900 US Railroad system built
 1940-1970 Interstate highway system
 1960-1970 Apollo mission to the Moon
 1950-1990 Cold War, nuclear threat
 1960-1980 Green revolution, agriculture
 1990-2010 Internet; Global change
Everybody Likes a Challenge
 1990-2010 Recognizing climate change
 2010-???? Mitigation and Adaptation