Download Coral Reef Notes

Coral Reef Notes
Overarching Questions
• Should we permit tourists to visit the fragile coral reef
environment?
Observations of a Coral Reef
Key Characteristics of a Coral Reef?
• Colorful
• Extremely Diverse Life
• Located in Warm Water
• USUALLY located in Clear
Water
Why?
• Water is Nutrient Poor
• How is there so much
life in this area?
Interesting Facts about the Coral Reefs
• Though coral reefs cover leas than 1% of the Earth’s
surface, over 25% of all marine fish species find their
homes in coral reefs.
• The average growth rate of a coral reef is less than 3 cm
per year; hence it takes several years to form a large
• Coral is an animal related to jellyfish (A Cnidarian)
Anatomy of a Coral Reef (demo)
-Coral is a Cnidarian
-Reefs are made when each
individual coral organism – or
polyp – secretes a skeleton of
calcium carbonate
-Zooxanthallae (an
algae/protist) will inhabit the
Coral
Factors necessary for
coral reef formation:
Coral (animals) need:
• Salt water: 34-37 ppt
• Hard substrate to settle
on as larvae
• Food
• Oxygen
Zooxanthellae (algae)need:
•
•
•
•
•
•
NOT A PLANT, A PROTIST
Sunlight
Nutrients (nitrogen)
Warm temperature:~20ºC
Clear water
Carbon dioxide
Mutualism
Coral (animals) need:
• Receives Food
• Receives Oxygen
Zooxanthellae (algae)need:
• Receives protection
• Receives Carbon Dioxide
Importance of Coral Reefs to the Environment
• The Reefs built by corals provides homes for millions of
different species
• Involved in nitrogen fixation  provides food to fish
• Photosynthesis of the Zooxanthallae  absorbs carbon
• Nursery for different organisms. Why?
Importance of Coral Reefs to Humans
• Coral reefs are widely used in the treatment of cancer, HIV,
cardiovascular diseases and Asthma.
• Porous limestone skeletons of the corals have been used in
grafting human bones.
• Important source for the fishing industry
• Protect coastlines from storm surges
• Stimulate economy through increasing tourism
Organisms of a Coral Reef
Corals
Leafy Sea Dragon and Weedy Sea Dragon
Clownfish
Blue Tangs
Parrot Fish
-They cannot digest
Coral, so they pass the
crushed Coral  makes
the nice white sand
-Eat Coral with
their strong beaks
Class Cephalopoda (Phylum Mollusca)
•
•
•
•
•
•
•
•
“Head-Foot”
Intelligent (largest centralized brain of all the invertebrates)
Soft Bodied
Sophisticated Eyes (but Colorblind)  Visual Predator
Tentacles with suction cups
Contain Chromatophorees (color changing cells)
Contain Iridophores (reflective cells)
Beak
Cuttlefish
Octopus
Squid
Squid External Anatomy
Squid Internal Anatomy
Gills
Gonads
Pen
(Cannot be
seen in this
picture)
Environmental Issues
The Ocean is a Carbon Sink
What does this mean?
-The Ocean absorbs
Carbon Dioxide
Atmospheric
CO2
Oceanic
CO2
pH
Ocean
acidification
Temperature
Coral
Bleaching
What are the effects of too much CO2?
1. Ocean Acidification
2. Coral Bleaching
Ocean Acidification Lab
What is Ocean Acidification?
What is Ocean Acidification?
Normal Conditions
• The Ocean is naturally Basic
(pH ~8)
• Calcium Carbonate (CaCO3)
present in the water and
available for organisms to
use for their shells and
skeletons
What is Ocean Acidification?
Atmospheric
CO2
Oceanic
CO2
• A decrease in Ocean pH means that
there are more H+ ions  will react
with the Carbonate Ions to form
Bicarbonate INSTEAD of Calcium
Carbonate
pH
Ocean
acidification
What do you observe?
Ocean Acidification  Decrease in Calcium Carbonate
• It DOES NOT mean that the ocean is so acidic that it is
dissolving the shells of bivalves and skeleton of corals…yet.
• It DOES mean that there is not enough Calcium Carbonate for
these shelled organisms to build their structures
What is Coral Bleaching?
Temperature
Atmospheric
CO2
Oceanic
CO2
Coral
Bleaching
• An increase in CO2 (a greenhouse gas) causes an increase in
temperature
• The increase in temperature is an environmental stressor for
the Coral
• Other environmental Stressors: pH change and pollution
What do you observe?
What is Coral Bleaching?
• As Corals are stressed, they
will start to expel and/or
actively digest their
zooxanthellae
• If the stress is intense, they
Corals will expel all their
zooxanthellae leading to the
bleached look
Effects of Coral Bleaching
• The corals can survive a bleaching
episode
• They are animals so they can still eat
food to live
BUT
• They are more vulnerable to diseases,
infections, and mortality
• Zooxanthellae can be resorbed but will
not survive long outside of the coral
Natural Threat: Crown of Thorn
Natural Threat: Crown of Thorns
• When balanced, the Crown of Thorns play an
important role of consuming the fast growing
coral; therefore, regulating the population and
enabling slow growing corals to grow
• Cyclical outbreaks are natural but they have been
happening more often than previously
-possibly linked with the warmer waters
because the sea star spawn during warmer
seasons
Case Studies
• Human Impacts on Coral Reefs
• Crown of Thorns Impact