What is a Coral Reef, Exactly?
Coral reefs are underwater structures
formed by calcium carbonate which is
produced and released by coral polyps.
Coral polyps are marine animals similar
to the sea anemone. The massive
colonies of shells from the coral polyps
help to form coral reefs.
Coral reefs grow best in warm, shallow
waters.
“Rainforests of the Sea”
•Reefs form complex ecosystems that
are home for more than 1 million
species- possibly the most diverse
ecosystem on Earth.
•Provide a home for over 25% of all
marine life Yet, Coral reefs make up
less than one-half of one percent
(.005) of all ocean area.
Why do we need Coral Reefs?
Reefs help buffer the coastlines of over
100 countries from erosion and flooding
Coral reefs bring in billions of dollars in
economic activity and are home to
nutrients and organic compounds with
pharmaceutical potential.
Who Needs Coral Reefs?
It is estimated that 500 million people
depend on reefs for food, building
materials, tourist income or coastal
reef protection.
30 million people are completely
dependent on reefs for their
livelihoods or land.
Life within the Coral Reef:
Biodiversity
Life on a Reef
Organisms that are part of Reefs include:
1
2
Fish– Some fish feed on small animals living near the coral
or on the coral itself; other fish, including some sharks
cruise the perimeter of the coral reef.
Algae– Though a vital part of reef life, overfishing and
excess nutrients from onshore can lead to algae
encroachment, where algae can outcompete and kill
the coral
Life on a Reef, Continued
:
Item
3
Seabirds– Coral Reef systems provide habitats for seabird
species, many of which are endangered. The short-tailed
albatross has only 2200 surviving species
Item
4
Cnidarians– organisms like jellyfish with specialized cells
called cnidocytes. Cnidocytes are used used mainly for
capturing prey which ranges from the size of plankton to
animals larger than themselves.
5
Other inhabitants–Sea snakes and land based
reptiles (crocodiles, lizards) feed on fish and
their eggs.
Coral Reef Survival:
Threats
Reefs at Risk
Statistics
•Approximately 10% of the world's
coral reefs are dead
• Around 60% of the world's reefs
are at risk due to human-related
activities.
• In Southeast Asia it is estimated
that 80% of reefs are endangered
Coral Bleaching
What is it?
The exposure of the white
skeleton of coral due to loss
of the microscopic algae
living inside coral polyps
which give them color.
•Scientists use language like
mitigate and adapt to describe
solutions to this threat.
•They hope to identify and
minimize environmental stressors
which may prevent coral reefs
from recovering for coral
bleaching.
•Are mitigating and adapting good
approaches? Will these solutions
last?
Additional Threats to Consider
•Human Contact
•Sewage & Runoff
• Destructive Fishing Practices
•Tourism (Including diving and snorkeling)
•Ocean Acidifcation
The Canary in the Coal Mine
•Coal miners used canaries to indicate
whether a change in atmosphere had
occurred. Toxic gasses would show visible
affects on the canary before the miners.
•Coral Reefs are considered the “canary in
the coal mine” in respect to climate change
because they show noticeable changes
first.
•Why is this a challenge?
Future Solutions:
Reef Survival
Marine Protected Areas (MPA’s)
• Marine Protected Areas describe
areas or regions which have been
placed under some restrictions in the
interested of protecting the
environment.
•MPA’s do not necessarily restrict all
human activity, but instead place
limitations on what activities are
allowed, for example fishing, fishing
seasons, catch limits, etc.
•MPA’s include a variety of reefs, but
may not be a sustainable solution for
the future.
Solutions for Reef Ecosystem Integrity
From the World Resources Institute
•Integrating coastal zone management
• Effective environmental laws
•Educating policy makers and the
public about how reef habitats should
be maintained
•Promoting environmentally sound
practices for land use
•Minimizing illegal fishing and
developing sustainable fisheries
•Developing disaster strategies
Fast Forward:
•Brainstorm future threats
to coral reefs
•How could ecotourism lead
to positive effects on coral
reefs?
•How will coral reefs be used
for in 50 years?
• What will happen to living
conditions on land if Coral
Reefs die out?