coral reefs. what is a coral reef? caco 3 from living things reef builders –corals –algae...

Coral Reefs

What is a Coral Reef?

• CaCO3 from living things

• Reef builders– Corals– Algae– Sponges– Bryozoans– Shells

Reef Corals (Hermatypic)

• Anthozoans (no medusa stage)• Scleractinian corals = “true” corals• Zooxanthellae

– Symbiotic dinoflagellates• Photosynthesize• Help deposit skeleton

• Most are colonies from founder polyp– Interconnected digestive and nervous

systems

Coral NutritionCoral Nutrition Zooxanthellae Predation on

zooplankton Polyp tentacles Mucus Mesentarial

filaments

Zooxanthellae Predation on

zooplankton Polyp tentacles Mucus Mesentarial

filaments

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Coral ReproductionCoral Reproduction

Asexual

Sexual Some internal Broadcast

spawning

Asexual

Sexual Some internal Broadcast

spawning

Corals in action!Corals in action!

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Coral RestrictionsCoral Restrictions

Light for zooxanthellae (usually best in shallow, clear water)

Warm water (but not too warm!!) - 68-86 F Substrate availability Salinity Sedimentation Pollution and eutrophication

Light for zooxanthellae (usually best in shallow, clear water)

Warm water (but not too warm!!) - 68-86 F Substrate availability Salinity Sedimentation Pollution and eutrophication

Coral Coral BleachingBleaching

Normal ReefNormal Reef

BleachedBleached

Fringing ReefsFringing Reefs

Near shore - more vulnerable to? Reef flat

Wide inner area Shallow - may be exposed

Reef slope Steep outer area Much richer biologically

Near shore - more vulnerable to? Reef flat

Wide inner area Shallow - may be exposed

Reef slope Steep outer area Much richer biologically

Fringing ReefsFringing Reefs

Barrier ReefsBarrier Reefs

Lagoon Separates reef from shore Usually soft-sediment with gentle water

Reef flat May form sand cays (keys)

Reef slopes Back slope and fore slope

Lagoon Separates reef from shore Usually soft-sediment with gentle water

Reef flat May form sand cays (keys)

Reef slopes Back slope and fore slope

Barrier ReefsBarrier Reefs

AtollsAtolls

Ring of reef surrounding central lagoon Indo-West Pacific

Ring of reef surrounding central lagoon Indo-West Pacific

Reef Ecology

Reef Ecology

Nutrient CyclingNutrient Cycling

Symbiotic algae Zooxanthellae Also in sponges, giant clams, others

Animal waste Nitrogen fixation (cyanobacteria,

symbionts) Currents

Symbiotic algae Zooxanthellae Also in sponges, giant clams, others

Animal waste Nitrogen fixation (cyanobacteria,

symbionts) Currents

Eating Coral??Eating Coral??

Eating Coral??Eating Coral??

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Eating Coral??Eating Coral??

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Eating Coral??Eating Coral??

CompetitionCompetition

Sessile animals compete for space and light

Methods: Rapid growth Overgrowth Attack (poisons, stinging, digestions)

Sessile animals compete for space and light

Methods: Rapid growth Overgrowth Attack (poisons, stinging, digestions)

CompetitionCompetition

What about fish?What about fish?

Pre-settlement hypothesis Species present are result of larvae

settlement Competition unimportant

Post-settlement hypothesis Diversity determined by available niches and

competition

Pre-settlement hypothesis Species present are result of larvae

settlement Competition unimportant

Post-settlement hypothesis Diversity determined by available niches and

competition

SymbiosisSymbiosis

What is symbiosis? Do they have to live together?

Obligatory vs. facultative symbiosis Types of symbiosis

Mutualism (+,+) Commensalism (+, 0) Parasitism (+, -)

What is symbiosis? Do they have to live together?

Obligatory vs. facultative symbiosis Types of symbiosis

Mutualism (+,+) Commensalism (+, 0) Parasitism (+, -)

Mutualism: AnemonefishesMutualism: Anemonefishes

Why aren’t they stung?

Fish gain protection and place to brood eggs

Fish drives away potential predators of anemone, may provide nutrients

Why aren’t they stung?

Fish gain protection and place to brood eggs

Fish drives away potential predators of anemone, may provide nutrients

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Mutualism: CleaningMutualism: Cleaning

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Mutualism: CleaningMutualism: Cleaning

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