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An Introduction to Coral Reefs

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Coral is cousins to jellyfish and anemones (Cnidarians) ... Coral is Picky. Very specific habitats: Temperature: 73-75. F Depth: Less than 80 ft to 230 feet ... – PowerPoint PPT presentation

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Title: An Introduction to Coral Reefs


1
An Introduction to Coral Reefs
2
What is coral?
  • Its a living organism!
  • It is an invertebrate
  • 2 different types
  • Reef Building Hermatypic
  • Solitary Ahermatypic
  • Coral is cousins to jellyfish and anemones
    (Cnidarians)
  • Today we will talk mainly about reef building
    coral

Sun Coral Polyps
3
Where Can You Find Coral Reefs?
  • Coral is found all over the world
  • Tropical
  • Temperate
  • Polar
  • Only tropical corals build reefs

Coral reefs around the world
4
Coral Builds Reefs?
  • The animal portion of the reef is called a polyp
  • The polyp absorbs calcium carbonate out of the
    water
  • The calcium carbonate is used to build the reef

5
Reefs Corals Build
  • Corals can build three types of reefs
  • Fringing grows close to shore
  • Barrier also grows close to shore but has a
    lagoon separating it from the shore
  • Atoll a ring of coral that surrounds a lagoon,
    often grows on a submerged mountain or volcano

http//www.nos.noaa.gov/education/kits/ corals/med
ia/coral04a_240.jpg
6
Coral are Cnidarians
  • Soft bodied
  • Carnivorous
  • Stinging tentacles arranged in a circle around
    their mouth
  • Body symmetry
  • Specialized tissues

7
Cnidarians
  • Usually two life stages
  • Polyp
  • Medusa
  • Gastrovascular cavity
  • Food is broken down here but digested
    intracellularly

8
Cnidarians
  • Respiration and waste removal takes place through
    body walls
  • Nerve net
  • Some have a hydrostatic skeleton
  • Some move through jet propulsion

9
Anatomy of Coral
  • The coral polyps build a calcium carbonate cup
    called a corallite to live in
  • Coral has stinging cells called nematocysts

10
Stinging Cells
  • Nematocysts help coral catch food
  • They also help protect the coral
  • When the cell is stimulated, it releases a sharp
    barb
  • The barb will fire and catch the food and bring
    it back towards the mouth

11
Coral and Zooxanthella
  • Symbiotic relationship
  • Zooxanthella is an algae that lives in the skin
    of coral
  • Coral provides protection
  • Zooxanthella provides food and color!

12
Coral is Picky
  • Very specific habitats
  • Temperature 73-75?F
  • Depth Less than 80 ft to 230 feet
  • Salinity Normal salt levels (35ppt)
  • Light Zooxanthellae need light to survive
  • Sedimentation Being covered with silt interferes
    with photosynthesis
  • Desiccation being exposed to air. The corals
    will die if exposed too long
  • Coral likes areas with lots of waves
  • They are strong enough to withstand the pressure
  • Freshwater means more food
  • Waves remove silt
  • New water brings more oxygen

13
Asexual Reproduction
  • To reproduce coral can reproduce asexually or
    sexually
  • Asexual reproduction in corals is called budding
  • A baby polyp will begin growing off the adult
  • When it is ready it will detach and live on its
    own
  • This can not start new colonies, only help the
    old colony grow bigger

This is a hydra (cousin to coral) with two buds.
One bud (on the right) is older than the other.
14
Coral Reproduction
  • Sexual reproduction is called spawning
  • External fertilization
  • It can start new colonies
  • Sperm and eggs are released into the water column
  • The fertilized egg is then called a planula
  • The planula swims until it finds a good place to
    live

15
A New Home
  • Corals now have a choice of where to live
  • Corals are very sensitive and are rapidly dying
  • People are trying to help by creating artificial
    reefs

16
Arguments for Artificial Reefs
  • It can help build or rebuild a reef
  • It will increase fish populations by making new
    habitats

17
Arguments Against Artificial Reefs
  • Moveable
  • Chemical leaking and leaching into the ocean
  • It does not increase fish populations but rather
    moves them to one location away from their
    natural habitat which makes them easier to catch

18
Reefs in North Carolina
  • North Carolina has reefs too!
  • They similar to tropical reefs
  • Reef fish swept up on the Gulf Stream live here
    until winter
  • River beds that were covered when sea levels rose
  • Also made up of
  • Low rock ridges
  • Outcroppings
  • Coral patches
  • Ship wrecks
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