Transcript Reefs: Past, Present and Future

Reefs: Past, Present and
Future
What is a Reef?
There are three basic kinds of
coral reefs
Fringing reefs, barrier reefs and atolls
 Fringing reefs are coral reefs that grow
in shallow waters and border the coast
closely or are separated from it by a
narrow stretch of water
 Fringing reefs consist of several zones
that are characterized by their depth,
the structure of the reef, and its plant
and animal communities
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Reef Zones
Barrier Reefs
Barrier reefs are reefs that are
separated from land by a lagoon.
 These reefs grow parallel to the coast
and are large and continuous.
 Barrier reefs also include regions of
coral formation that include the zones
found in fringing reefs along with patch
reefs (small reefs), back reefs (the
shoreward side of the reef), as well as
bank reefs (reefs that occur on deep
bottom irregularities)
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Atolls
Atolls are annular reefs that develop at
or near the surface of the sea when
islands that are surrounded by reefs
subside.
 Atolls separate a central lagoon and are
circular or sub-circular.
 There are two types of atolls: deep sea
atolls that rise from deep sea and those
found on the continental shelf.
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Animals Associated with Coral
Reefs
Coral reefs provide habitats for a large
variety of organisms.
 These organisms rely on corals as a
source of food and shelter.
 Some organisms that use corals through
mutualism, commensalism and parasitism
are within the taxonomic groups Porifera
(sponges), Polychaeta (worms),
Gastropoda (snails), Crustacea (shrimp &
crab), Echinodermata (sea urchins) and
Pisces (fish).
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Reefs: Past
Reefs through geological time
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Reefs, in some shape or form, have been around for
a very long time.
Approximately 3.5 billion years ago microbialites
(calcareous organo-sedimentary deposits) begin to
appear in the fossil record.
These benthic microbial communities produce their
own hard substrate by sequestering raw inorganic
materials from the surrounding seawater.
For the next 2.5 billion years microbialites are
represented by photosynthesizing cyanobacteria
(blue-green algae)
Stromatolites
Stromatoporoids
El Capitan
Golden Spike Complex, Alberta
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Upper Devonian
Oil discovered + 40
years ago
4.5 billion barrels oil
17 trillion ft3 gas
Threat to coral reefs:
Hobbyists
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Hobbyists seeking fish and coral for their
aquariums
Aquarium owners are buying live coral at a rate
that has increased 12 to 30 percent a year since
1990
The U.N. Convention on International Trade in
Endangered Species (CITES) regulates trade for
2,000 species of coral
Live fish, soft corals, anemones, crustaceans,
mollusks and other creatures are not on the list
– Sea horse populations have dwindled by more than 25
percent since 1994
1997 I.Y.O.R.
International Year of the Reef
 Reefs
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– One of earth’s most diverse ecosystems
– Home & nursery to 0.5 million fish species
– Potential for biomedical resources
– Protection against storms
Biomedical Applications
Over 6,000 unique chemical
compounds
 Skin-Care Products
 Bone graft material
 Anti-Cancer Drugs
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– Didemnin B, diazonomide A, dolastatin 10
Reefs in Crisis
 Pollution from poor land use, chemical loading,
marine debris, and invasive alien species.
 Over-fishing and related harm to habitats by
fishing gear and marine debris.
 Destructive fishing practices, such as cyanide
and dynamite fishing that destroy large sections
of reef and kill many species not yet harvested.
 Dredging and shoreline modification in
connection with coastal navigation or
development.
 Vessel groundings and anchoring that directly
destroy corals and reef framework.
 Disease outbreaks that are increasingly
prevalent in reef ecosystems.
 Global climate change and associated impacts
such as coral bleaching, more frequent storms
and rise in sea level.
Land-based Pollutants
Thermal Pollution
 Nutrient enrichment
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– Sewage
– Agricultural runoff (fertilizers)
Pesticides, herbicides
 Hydrocarbons (oil exploration, boats)
 Sedimentation
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– coastal construction
– deforestation
– soil erosion
Overfishing
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Overfishing of herbivorous fish interacts
with the effects of eutrophication to
affect the community structure of coral
reefs. Jamaica is a classic example of a
phase shift from a coral reef dominated
community to a macroalgal community
Selective overfishing
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Selective overfishing of populations, for
example spawning aggregations, can
have particularly disastrous effects.
– one (1) 61cm female snapper produces the
same number of eggs as two hundred and
twelve (212) 41cm female snappers.
– 12.5kg of large snapper has the
reproductive potential of 233kg of small
snapper
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Destructive fishing practices can
destroy reef communities very
effectively in a very short span of time.
Dynamite fishing is an example that is
also very dangerous for the human
participants.
Destructive Fishing
Cyanide fishing is a destructive
fishing pratice common in southeast
Asia. Cyanide (or bleach), when
squirted into a crevice will
temporarily stun fish for collection
by hand.
 However, the cyanide also kills coral
and other invertebrates near the
fish's refuge
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Reefs in Crisis
10% of existing reefs destroyed
 30% threatened (destruction by 2020)
 65% depleted within 2 generations
 Greatest risk areas
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– Southeast Asia, East Africa & Caribbean
“Pollution, overfishing, and overuse have put
many of our unique reefs at risk.
Their disappearance would destroy the habitat
of countless species.
It would unravel the web of marine life that
holds the potential for new chemicals, new
medicines, unlocking new mysteries.
It would have a devastating effect on the coastal
communities from Cairns to Key West, Floridacommunities whose livelihood depends upon
the reefs.”
President Bill Clinton, August 1996
CORAL REEFS
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The “rain forests of
the sea,” coral reefs
cover more than
6,500 square miles in
the Caribbean, the
Gulf of Mexico, off
Florida and the
Pacific. They are
home to an estimated
550 species of fish,
and are major tourist
attractions
Economic Losses
 The loss of these fragile ecosystems would
cost billions of dollars
– Tourism and fishing industries
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Tourism
– $1 billion generated annually by tourism at Australia’s
Great Barrier Reef
– $1.6 billion by Florida’s reefs
– $90 billion by Caribbean reefs and beach tourism
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Fishing
– 6 million tons of fish also provide employment and protein
for about 500 million people
– Damage to coastal regions that are currently
protected by the coral reefs
Climate Projection Models
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Fate of coral reefs if increases in the emission
of greenhouse gases continued
– Corals can live only in water between 64 degrees
and 86 degrees Farenheit, coral bleaching can
be triggered by a temperature increase of just 1.8
degrees above the maximum
– “If we delay 10 years, the effect will be quite
severe, and that’s what this model is showing us.
A delay means the death of coral reefs for
probably as much as 1,000 years.”(Hoegh-Guldberg , director
of the Coral Reef Research Institute at Sydney University in Australia)
Coral Bleaching
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White spotting or
dead areas
Increase in surface
water temperatures
stresses the coral
Expulsion of
zoozanthellae
Coral Bleaching
Losses
A year 2000 report by the Global Coral
Reef Monitoring Network concluded that
27% of the world’s coral reefs were
“effectively lost”.
 The single largest cause was the El
Nino-related warming event of 1997-98,
which destroyed 16% in 9 months.
 The remaining 11% were lost to
sediment and nutrient pollution, overfishing and mining of sand and rock.
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Coral BleachingConsequences
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Unless global warming is reversed- coral
bleaching would increase in frequency and
seriousness until it occurred annually
everywhere as early as 2030.
A single bleaching event will take reefs
between 30 to 100 years to recover
Global warming would devastate coral reefs
by the middle of the 21st century and could
eliminate them from most areas of the planet
by 2100
Future
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March 2, 2000 — The intergovernmental U.S.
Coral Reef Task Force unveiled the first-ever
national plan to comprehensively and
aggressively address the most pressing
challenges facing reefs today
– FY 2000 Federal dollars specifically targeted to
cooperatively saving reefs $6 million to NOAA and $5
million to the U.S. Department of the Interior. The
President requested a total of $25 million for FY
2001
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National Plan
– Mapping
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$1 million per year from NOAA), NOAA estimates that all U.S.
coral reefs will be mapped by 2009.
– Monitoring
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integrated national reef monitoring system to profile and track the
health of U.S. coral reefs.
– Marine Protected Areas
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expanding the existing network of coral reef
protected areas
– All-Islands Coral Reef Initiative
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NOAA and the Department of the
Interior will provide $1.35 million in FY 2000 to assist
U.S. islands to improve coral reef
management and protection, including monitoring,
education and designation of marine
protected areas.
For More Information
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25 things you can do to save coral reefs
– http://www.noaa.gov/public-affairs/25list.html
Reef Resource Page
– http://www.indiana.edu/~reefpage/
Coral Reef Protection
– http://www.epa.gov/OWOW/oceans/coral/index.html
Ramsar and Coral Reefs
– http://iucn.org/themes/ramsar/about_coral.htm
Planetary Coral Reef Foundation
– http://pk.com/pcrf/
CORAL:The Coral Reef Alliance
– http://www.coral.org/