coral reefs coral reefs are similar to rain forests in that they are complex and diverse

Coral Reefs

Coral Reefs

Coral reefs are similar to rain forests in that they are complex and diverse

Coral ReefsCoral reefs are made of calcium carbonate CaCO3 deposited by

reef-building organisms like coral.

Coral Reefs

Coral polyp is a sac like stage of a Cnidarian with mouth and

tentacles on top.

Coral polyp

Coral ReefsWhat is a coral colony?

“Founder” coral divides over and over so all are clones that have a connected digestion system and

share a common nervous system. Touch one and they all respond.

Coral Colony cutaway

Coral Colony

Coral Reef What are zooxanthellae? Dinoflagellates that live within animal tissue Have symbiotic mutualistic relationships with

organisms providing food and color• They do photosynthesis and pass on some of

the organic matter to the coral.• Feed coral from inside.• Enable coral to make CaCO3 faster

zooxanthellae living in a mutualistic relationship with coral

Five Ways Coral Feed

1.Zooxanthellae are most important source of nutrition

2.Capture zooplankton with stinging nematocysts on tentacles

3.Capture zooplankton with mucus nets4.Digest organic material outside the body

with mesenterial filaments5.Absorb DOM dissolved organic matter

Coral polyp

Stinging Nematocysts

mesenterial filaments

Encrusting Coralline Algae

• Deposit of CaCO3 (limestone) add to structure of reef

• Forms algal ridge, block waves, prevents erosion

• Cements sediments in place,keeps reef from washing away

• Food source for fish

Encrusting Coralline Algae

Encrusting Coralline Algae

algal ridge

Coral reproduction

• Sometimes asexual, cloning• Some corals hermaphroditic….. Some

separate sexes • Have mass spawning ex. Great Barrier

Reef between Oct- Nov• Larva is called planula larva

Budding

Budding

coral spawning

coral spawning

Life cycle of a coral polyp

coral spawning

coral spawning

Conditions for reef growth

• Shallow clear water• Good light • Warm water- just right • Stable salinity

Clear Water

Other Reef Builders:• Oysters

• Polychete worms

• Shells of snails, clams, other mollusks, sea urchins, crustaceans, sponge.