Transcript Life on an Ocean Planet - Home
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► Biological Resources – Marine Mammals
► Biological Resources – Algae, Aquaculture and Medicine
► The State of the World’s Fisheries – A Bleak Picture
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Resource Classification
All resources have political and environmental significance because they all have economic value.
Two common categories for classifying marine resources are:
Renewable
and… Renewable resources are those that growing organisms, sunlight, or other processes naturally replace.
…
Nonrenewable
Resources Nonrenewable resources are those that natural processes don’t replace, or that do so at such a slow rate that they are not replenished in a human lifespan.
Physical
and… Physical resources don’t involve biological processes. They include minerals, energy production, and recreation.
…
Biological
Resources Biological resources involve bioproductivity, such as fisheries and kelp harvesting.
Most marine biological resources are
potentially
renewable, but some are not. It happens
when a fishery takes a species from the ocean faster than it can reproduce and maintain its population
. Whaling is an example of this.
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Energy
Among the physical marine resources,
petroleum
and
natural gas
are the most important to economic contribution. About one third of the world’s crude oil and about a quarter of the natural gas comes from the sea.
Petroleum and natural gas form from the remains of primarily marine organisms
, such as plankton and soft-bodied benthic organisms.
Seismic instruments are used to help find oil and natural gas.
Physical characteristics of the rock surrounding oil and natural gas are important.
This determines where the oil or gas collects
.
Source rock
is where hydrocarbons originate, and collect in the spaces underneath
reserve rock
. This is called an oil or gas reserve.
Sound waves detect the oil and natural gas reserves as low-density pockets in the reserve rock.
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Energy
(continued)
Oil companies use platforms to drill from
through sediment and rock into the reserves. to extract oil and gas by drilling Special drilling equipment is used to minimize the risk of an oil spill or gas leak.
Methane hydrates are ice crystals containing methane
found on the continental slope.
The unusual hydrocarbon deposits consist of frozen water molecules that create a “cage” within sediment. Each “cage” holds a single methane gas molecule.
They are another form of non-renewable hydrocarbon.
They are not currently used as an energy source because
it is very expensive to recover them and they are relatively dangerous to handle
.
Technologies for handling methane hydrates are in development.
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Salts and Minerals
Ferromanganese Nodules - Nodules are rich in
copper, nickel and cobalt as well as iron and manganese
. This makes ferromanganese nodules tremendously valuable.
Unfortunately,
the cost of recovery at present exceeds the worth of the minerals
.
Magnesium Compounds - About half the worldwide magnesium production
comes from seawater
. Magnesium is the third most abundant element dissolved in seawater. It occurs as magnesium chloride and magnesium sulfate.
Salts - Evaporites are the salts left behind when seawater evaporates.
Manufacturers use evaporites in the production of
fertilizers, medicines, wallboard, other building materials, and table salt
and food processing.
. Table salt in turn is used for snow and ice removal, water softeners, agriculture
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Salts and Minerals
(continued)
Phosphorite - Phosphorite or phosphate rock deposits are the
remains of marine organisms
that live in areas with extensive upwelling. Offshore phosphorite deposits are currently uneconomical to exploit.
Today terrestrial sources are mined. It is estimated these deposits may be depleted by the mid 21st century.
To avert a crisis in agriculture/industry, offshore deposits may be important
.
Marine Muds and Metals - Hydrothermal vent seawater carries large quantities of dissolved metals and minerals including zinc, iron, copper, lead, silver, cadmium and sulfur.
In the Red Sea are hot brines producing muds rich in metal sulfides, silicate, and other oxides in a high enough concentration to make recovering them economically feasible.
Seamounts are potential resources, in particular cobalt deposits.
Gravel and Sand
Sand and gravel
are important marine resources. They are second to gas and oil in terms of their annual economic value.
Each year industry mines more than one billion metric tons of sand and gravel from offshore deposits.
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Energy
The sea provides several types of renewable energy for human use:
1. Wave action accounts for two methods: 1.
Building a caisson
with an opening under water that permits waves to enter and compress air in the chamber forcing it through a turbine to generate electricity.
2.
Placing a series of buoys
that rise and fall in the waves cranking a wheel in a circle. An axle coming off the wheel turns a generator.
2. Tides can be be used for energy where tidal change is 3 meters(10 feet) or more. As the tide flows in and out of two way dams, its energy is used to turn turbine generators. One in France produces 500 kilowatts yearly.
3. Warm surface water is used by Ocean Thermal Energy Conversion (OTEC) to vaporize liquid ammonia which in turn drives a turbine. Water is piped back to the deep sea.
Of the three, the most feasible appears to be
harnessing wave energy
.
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Fresh Water
The single most important factor determining how many people can live in a given area is the availability of fresh water.
Human population is rising
, and the demand for fresh water with it.
The supply isn’t keeping pace
, making this resource a growing concern as we move through this century.
Desalinization
– getting fresh from seawater – involves removing dissolved salts. Currently there are more than 7,500 desalinization plants worldwide, 60% of which are in the Middle East. The Western Hemisphere accounts for only 12% of the fresh water produced by desalinization. Recovery methods include: Boiling seawater - capturing and condensing water vapor.
Freezing seawater - salt is left behind and fresh water is produced.
Reverse osmosis - forcing seawater through a semipermeable membrane under pressure letting the water through, but holding back the salt.
Covering large shallow pools of seawater with plastic and recovering the condensation that forms underneath the covers.
One bottled water company even melts icebergs on special barges to get fresh water.
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Nonextractive Resources
You may not think of these as resources, but they are.
Nonextractive resources are those we obtain from the sea without removing anything from the sea
. The two most conspicuous of these are
sea transport shipping
and
recreation
.
After WW II,
the invention of the cargo container
revolutionized sea transport shipping. Standardized cargo containers made it possible to quickly load and unload ships.
Modern ships can hold more than 4,000 containers.
Ecotourism
focuses on visiting and experiencing natural environments and wildlife. Much of it is on or near the sea.
On the positive side
, in a growing number of destinations local people are realizing that they need to preserve the local environments.
On the negative side
, some areas have trouble keeping pace ith the rising number of tourists. Construction and traffic are putting strain on the areas’ ecology. Something seemingly as harmless as feeding fish can change wildlife behaviors.
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Whales
Until 1868,
primitive technology made whaling dangerous
and difficult.
With the crude methods of harpoon and longshore boats, comparatively few whales could be taken and whale populations remained stable.
Everything changed in 1868 with the invention of the modern harpoon gun.
Whale populations have declined drastically
the 20th century.
during International whaling has been so successful that from an estimated whale population of 4.4 million in 1900, today the estimated population is around 1 million.
In 1982, the International Whaling Commission (IWC) called for an indefinite moratorium on commercial whaling that became effective in 1986.
The gray, blue and humpback whales seem to be on the rise in the Pacific
.
Unfortunately, the right and southern blue whales in the North Atlantic appear to still be declining
.
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Whales
(continued)
Whaling continues despite the moratorium for several reasons
: IWC is a voluntary organization and even members don’t have to abide by its rulings.
Whaling continues with the IWC’s allowance for aboriginal hunting to preserve their cultural traditions. Often the “traditions” are carried out with modern equipment.
Another exemption is for scientific whaling. Allowing whales to be taken as specimens for study. Japan, in particular, continues to hunt whales using this clause with their government authorizing 400 whale kills annually. These “specimens” are sold to wholesalers and used as food in school lunches.
Other Cetaceans
Several small cetaceans are not protected under the moratorium:
Dolphins
have become the most endangered of the cetacean. They and
small whales
are a
by-catch
problem in tuna fishing.
Many countries eat dolphin. “Dolphin” on a menu in the US is a mahi-mahi fish. “Dolphin” in Peru is dolphin.
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Seals and Sea Lions
Historically,
seals and sea lions
have been biological resources exploited for their fur and for food.
Although the marine mammal fur trade no longer exists in the US due to the
Marine Mammal Protection Act
and consumer pressure, worldwide
up to half a million of these seals and sea lions die for their fur annually
.
World opposition continues to pressure Canada to ban the harp seal hunt for the pups’ fur. The killing of harp seal pups continues. So public opposition will continue, if for no other reason than that many consider it offensive to exploit these harmless and appealing pups.
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Algae
Marine algae is another resource used as food.
Annually, the Japanese consume nearly 150,000 tons of
red algae nori
.
The commercial product
algin
, which comes from the mucus in kelp and other marine algae, is useful in other applications.
food processing
and Algin is used as a food source in salad dressing, ice cream and is used to clarify beer and wine. It is also used in paint and abrasives.
The industry uses nearly $250 million worth of algin annually.
Farming the Sea
The growth trend in
aquaculture
is steeply upward. Currently it is growing three times faster than livestock production on land and may exceed it in the next decade.
Today about
25% 30% of the world’s seafood
comes from aquaculture.
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Farming the Sea
(continued)
There are problems with farming the sea: Aquaculture also has problems similar to raising livestock on land.
Some farmed fish species take fish to feed them – salmon for example.
Keeping many animals in close quarters tends to allow disease to spread rapidly. Drugs given to farmed fish to prevent disease pass through them into the environment.
Many pens release concentrated waste in the form of nitrates, leading to plankton blooms.
Aquatic farms consume resources that wild organisms would use.
Raising species not indigenous to the area raises a risk of throwing the local ecological balance off should some escape.
It can also compromise the gene pool of wild species if the domestic animals breed with them.
New Medicines from the Oceans
Bioprospecting
is the search for organisms with pharmacological or other chemical benefits.
Bioprospecting is important in the development of new drugs because
it is in nature that chemists often find new ways to fight disease
.
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Fisheries for Food and Industry
About
18%
of the protein we eat in the US comes from the ocean. Worldwide, it accounts for only about 4% and varies by nation and culture.
Commercially important fish are found primarily in two places:
the water of the continental shelves and a few offshore regions with abundant upwelling
.
Continental shelves and upwellings have high productivity because of the
ample supply of nutrients and sunlight
.
Clupeids – herring, sardines and anchovies
group that is taken for commercial harvest.
account for the largest single
Industrial fishing
is catching for purposes other than direct human consumption.
Over one third of the commercial fish catch is industrial
.
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Trends in the Worldwide Commercial Fish Catch
Since WW II, the worldwide annual catch has been greatly increasing
.
The
commercial extinction of many target fish
, e.g. orange roughy, and
the decline of others
including cod fisheries, raises doubts in the minds of scientists about the accuracy of the FAO’s estimates and reports.
Predicted trend is that soon the
worldwide fisheries will not be able to meet the rising demand
. Even the FAO estimates that by 2010, the worldwide catch will fall short of the demand.
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Maximum Sustainable Yield and Overfishing
The concept of
maximum sustainable yield
management.
lies at the heart of fisheries
It is the number of a target species that fisheries can take without jeopardizing future populations
.
The precise definition of
overfishing is taking more of a species than the maximum sustainable yield
.
Evidence indicates overfishing in virtually all the world’s fisheries.
Fleets catch less than in past years, yet have to range farther for fish.
Indications are that half the marine fisheries are overfished or already commercially extinct.
The
FAO
estimates that 70% of the worldwide fish stocks are overfished or depleted.
The National Marine Fisheries Service
estimates that 50% of the fish stock in US waters is over fished.
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The Problems with Overfishing
The fishing industry has become more efficient and blind to the threat.
By refining technology and methods, they are taking ever larger proportions of declining fish stocks
.
They are also responding
by turning to new, unexploited fisheries
.
Problems associated specifically with overfishing species low in the food web.
The first is that
these species are food for higher species
.
A second problem is that
it allows the proliferation of other organisms low on the food web
.
There are also indirect problems related to overfishing:
1. Humans aren’t the only organisms eating fish. Alaskan stellar sea lions are in decline. The decline is thought to be the result of heavy commercial fishing for pollock.
2.
By-catch
is the unintentional capture of organisms.
Estimates indicate this accounts for 25% of the catch. By-catch involves not only fish, but birds, mammals, fish, and reptiles.
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Recommendations for Sustaining the World’s Fisheries
In June 2003, the
Pew Ocean Commission
, a respected group of US scientists, wildlife advocates, natural resource managers, and politicians made these
four recommendations
resources.
to restore US fisheries as sustainable biological 1. Make the principal objective of US fisheries policies the protection of marine ecosystems.
2. Create an independent government agency responsible for managing ocean resources.
3. Invest in more marine research over the next five years. The commission recommended doubling current funding.
4. Establish a network of marine reserves or protected areas.
Commercial Fishing Methods
15 - 21 Five Primary Methods of Commercial Fishing
The Economics of Commercial Fishing
It costs more to catch fish than is made from selling fish. Fishing fleets spend about $124 billion to catch $70 billion in fish.
The fishing industry survives because of global government subsidies
.
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The Origin of Territorial Waters
In 1604, Dutch jurist Hugo Grotius wrote
De Jure Praedae
(
On the Law of Prize and Booty
), the most important part of which was a chapter defending free access to the sea by all nations. It took about 100 years, but finally it was internationally recognized.
Nations agreed to territorial water over which coastal nations had complete control
.
The seaward boundary was set at 5 kilometers
(
3 miles
), not coincidentally the maximum effective range for cannon fire at the time. Beyond this limit was the high sea (international waters) belonging to no one.
The Truman Proclamation
In 1945, President Harry Truman issued this proclamation claiming all physical and biological resources on the continental shelf of the continental United States.
Very quickly other nations followed suit.
The proclamation changed the concept of international waters by widening the concept of territorial water
.
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Exclusive Economic Zones
UNCLOS
is the
U
nited
N
ations
C
onvention of the
L
aw
o
f the
S
ea.
It established the concept of the
exclusive economic zone
(
EEZ
).
A nation’s EEZ extends 370 kilometers
(
200 nautical miles
)
from the shoreline
.
Within EEZ, a nation has complete control of all resources, economic activity, and environmental protections.
Areas beyond the EEZs are the high seas or international waters belonging to no one country
.
One of the more controversial aspects of UNCLOS was the establishment of the
International Seabed Authority plan
. This plan said that
mineral wealth recovered from the seabed in international waters must be shared internationally
.
Because mineral wealth is to be shared internationally, the US, Canada, and Great Britain have not ratified the UNCLOS treaty.
In 1983, the
US proclaimed its own EEZ within 200 nautical miles of its coasts
.
This proclamation shares the limits
,
but omits provisions about shared resources in international waters
. Several other countries that have not ratified UNCLOS have similarly declared EEZs of their own.
The Ultimate Resource
Biodiversity
is the concept that the preservation of the Earth and ecosystems relies on the broad genetic diversity of all the organisms on Earth.
We never know when losing one or more species is losing too many or just how important each single species is or when losing this species is the one that counts.
The importance of biodiversity is that every organism is a biological resource
.
Even if there is no direct use of an organism
,
it is important because it is part of what keeps life going
.
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