Transcript 04 APES Coralreefs

Destruction of
the Coral
Reefs
Coral Reefs …
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What they are
Why they are important
How they are being destroyed
How to help preserve them
How are Coral Reefs Made?
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Corals (tiny animals, called polyps) secrete stony
cup of limestone around themselves as a
skeleton
Polyps
The polyps divide as they grow and form coral
colonies - As the coral colonies build up on top of
each other, they gradually form a coral reef
Individual colonies may be up to 1000 years old
& Coral reefs may be many thousands of years
old
Reef locations
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Grow mainly in warm areas
between Tropic of Cancer and
Tropic of Capricorn
Most diverse is the Great Barrier
Reef in Australia - over 3000
different plants and animals
Types of Reefs
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Fringing Reef – lie around islands & continents
& are separated from the shorelines by lagoons
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Barrier Reef – grow on the edge of continental
shelves and also are separated from shorelines
by lagoons
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Atolls – a central lagoon and are circular or subcircular. There are two types of atolls: deep sea
atolls that rise from deep sea and those found
on the continental shelf.
Types of Reefs
Fringing Reef
Barrier Reef
Atolls
Why Reefs Are Important…
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Biodiversity importance
As a Food Resource
Source of Economic Wealth
Medicinal Use
Coral reefs are often called the
“Rainforests of the Sea”
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About 4,000 species of fish and 800
species of reef-building coral have
been identified
As a vital food source
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Globally, one-fifth of all animal
protein consumed by humans comes
from marine environments
Coral reefs provide
food for one billion
people in Asia alone
Economic importance due to
tourism ...
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Florida’s reefs contribute $1.6 billion to
the economy from tourism alone
Caribbean countries
derive half of their
GDP from tourism
($8.9 billion in 1990)
Coral reefs can save human
lives...
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Treat infections, viruses, and other
diseases
Prevent and treat skin cancer
Provide bone grafts
Coral reefs are a valuable
resource
Average Global Value of Ecosystem Services ($/HA/YR)
7000
6000
5000
4000
3000
2000
Coral Reefs
Tropical
Forests
Temperate
Forests
1000
0
"As the 'rain forests of the sea,' coral reefs provide services estimated
to be worth as much as $375 billion annually, a staggering figure for an
ecosystem covering less than one percent of the Earth's surface." -U.S. Coral Reef Task Force, March 2000
Threats to Coral Reefs From…
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Coastal development
Pollution
• Marine
• inland
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Overfishing/ Destructive fishing
Overexploitation of Resources
Natural Disturbances
Coastal development ...
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Dredging
Constructio
n materials
Building on
reefs
Unregulated
tourism
Tourism/ Recreation
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corals easily broken by trampling when
people walk out to the reef;
snorkelers and divers may kill polyps
simply by touching coral colonies
Marine Pollution
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Oil spills
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Discharge of oily
ballast water
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Large power
plants change
water
temperatures by
discharging
extremely hot
water into the
coastal water
Inland Pollution
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Erosion from increased
forest clearing & intense
agriculture causes silt to
wash into water, clouding
it, and suffocating the coral
Sewage & agricultural
fertilizer runoff increases
nutrients in ocean, which
produces more seaweed
that hurts the coral
Lack of sunlight from
eutrophication/turbidity can
cause bleaching
Overfishing
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removal of reef fish causes ecosystems to
be unbalanced
allows more competitive organisms, such as
algae, to become dominant
Destructive fishing damages
reefs
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Due to decreased yields,
fishermen forced to
change methods to catch
enough fish to sustain
needs:
• Fishing with cyanide
• Blast Fishing
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Not only do these
practices kill all fish in the
affected areas but also
severely damage the corals
Destructive fishing practices in
Southeast Asia are widespread
Areas at
High Risk
Overexploitation
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Corals popular as decorations, jewelry,
and souvenirs
• People collect pieces of coral themselves
• buy pieces from a "curios" shop – shops
receive corals from well developed colonies
to make them the most money
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Coral is also mined – used to build houses
and make roads, or is burnt to make lime.
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Use for aquariums
Natural disturbances
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Destroyed by hurricanes and tropical storms
Diseases, such as black-band disease –
spreads over colonies, progressively killing
the polyps
The crown-of-thorns starfish feeds on
corals, if many, can reduce a reef to a mass
of dead coral skeletons quickly
…Coral Bleaching
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greenhouse effect - may cause increases in
sea temperature
Sea water that becomes too warm causes
corals to turn white, or bleach, a reaction
that occurs if coral polyps are stressed.
Overexploitation and coastal
development are the greatest threats
to reefs
40%
35%
30%
25%
20%
15%
10%
5%
llu
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The Reefs at Risk indicator
Low Risk
Medium Risk
High Risk
Disturbing Results…
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58% of the world’s
reefs are at risk from
human activities
Reefs of Southeast
Asia are the most
threatened
90% of reefs are
overfished
Almost two-thirds of
Caribbean reefs are
threatened
Coral Graveyard
The world’s reefs are not
sufficiently protected ...
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40 countries contain no protected
reef areas
Management goals of most marine
protected areas (MPAs) are not
met
Preserving Coral Reefs
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“Reefs at Risk”
• Project to make people aware of the
status of coral reefs
• Has developed series of indicators of
human pressures on coral reefs
Treating sewage protects reefs
and human health
Solutions to threats of Coral
Reefs ...
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Promote sustainable use of marine
resources.
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Impose environmental regulations on
imports of fish that are caught using
blast or cyanide fishing methods.
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Increase number and size of marine
protected zones.
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Encourage research and testing on
aquaculture that could provide a large
supply of desirable seafood.
…Solutions Continued
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Increase public education on the value of
coral reef animals and plants to the entire
planet
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Continue monitoring coral reefs to
evaluate the impacts and solutions to these
impacts and to determine if management
practices are working and whether
endangered species are recovering.
Seven success stories
Apo
Bermuda
Healthy Reefs