1. Corals
Landlords of the Reefs

2. What should you know about corals?
They are animals
Plants live inside of them
Two kinds
Soft corals
Hard corals (These build reefs!)
They are made of tiny polyps (which look like upside-down jellyfish)

3. Hard Corals The Reef Builders
Polyps build hard limestone cups around their bases
The cups cement together to make a coral colony
Reefs are made of hundreds of hard coral colonies next to and on top of each other

4. What’s a Polyp?
Tentacles release stinging cells when something brushes by them
Polyps make their own limestone cup to hide in during the day
At night, polyps come out to catch plankton floating by.

6. Zoo-what!?! Algae, Coral Polyps’ Tenants
Inside polyps live zooxanthellae, which are algae.
Zooxanthellae give corals their color.
Since algae are plants, they use sunlight and CO2 to make food (the process known as photosynthesis).

7. Zooxanthellae -Symbiotic dinaflagellate algae (Pyrophyta)
Benefits for coral:
-fixed carbon
-enhanced calcification
-nutrient efficiency
Benefits for zooxanthellae:
-nutrient supply from host
-stay in photic zone
-UV protection

8. Symbiosis: So Happy Together
Two organisms living together and helping each other is called symbiosis.
Zooxanthellae make oxygen, remove the polyp’s wastes, and make food for the polyp from photosynthesis.
Coral polyps protect the zooxanthellae, release CO2, and provide it with necessary nutrients from their own waste.

9. 3 forms of Symbiosis Mutualism- Both organisms benefit
Commensalism- one organism benefits and the other is not affected
Parasitism- one organism benefits while the other is harmed.

10. Mutually Beneficial Symbiosis A Win-Win Situation
Egyptian Plover bird and crocodile
Bumblebee and flowers
Your intestine and bacteria

11. Parasitic Symbiosis A Win-Lose Situation
Tapeworms and intestines
Ticks and dogs

12. How are these mutually symbiotic?
Drivers and passengers in a carpool
Tenants and landlords
                                

13. Which form of symbiosis is this? Why?
Mutualism

14. How about this? Why?
Parasitism

15. And last. WHY?
Commensalism

17. Reef Ecology Trophic Structure
– Primary producers: zooxanthellae and macroalgae
– Primary Consumers: coral and invertebrates
– Tertiary consumers: predators
• Keystone Species
– Sea urchins, Crown of Thorns Sea Star

18. What is a keystone species?
What is a keystone species?
A keystone species is a species that has a much larger effect on its environment relative to how many of them are present. Such a species affects many other organisms in an ecosystem and help to determine the types and numbers of other species.
So why were the sea urchin and the crown of thorn sea star keystone species?

19. One third of all marine species live in coral reef systems

20. Coral Colonies – Butterflies, damsels, wrasses, velvet fishes, gobies,
puffers,
filefishes,
hawkfishes,
triggerfishes,
and
squirrelfishes

21. Conditions for coral Sunlight Low nutrient levels Certain salinity
Water temperature between 18 and 29 degrees Celsius
Water circulation

22. What is coral bleaching?
Healthy
coral
Bleached coral
The corals expell their zooxanthellae symbiont- Coral bleaching is caused by stress.
Poll question: what might be stressful for a coral?

23. What can stress a coral? High light or UV levels Cold temperatures
Low salinity and high turbidity(cloudiness of water) from coastal runoff events or heavy rain
Exposure to air during very low tides
Major: high water temperatures
Poll answer before this
Photos: AIMS and GBRMPA

24. Man made threats to coral reef systems
Global warming leading to coral bleaching
Runoff from chemicals and nutrients from land
Sedimentation
Overfishing
Physical damage from tourists and fishing
pollution

25. What turns the coral white?
Healthy coral with algae
Bleached coral with no algae
- As a stress response, corals expel the symbiotic zooxanthellae from their tissues
- The coral tissue is clear, so you see the white limestone skeleton underneath

26. Can corals recover? Yes, if the stress doesn’t last too long
Some corals can eat more zooplankton to help survive the lack of zooxanthellae
Some species are more resistant to bleaching, and more able to recover
Photos: AIMS and GBRMPA

27. Does bleaching kill corals?
Yes, if the stress is severe
Some of the polyps in a colony might die
If the bleaching is really severe, whole colonies might die
Bleaching in Puerto Rico killed an 800-year-old star coral colony in 2005

28. What does it really matter if coral die or not
What does it really matter if coral die or not? What’s the impact of bleaching?

29. Your answer!!! (The short version)
If coral reefs were to become bleached and die it would have a domino effect of the ecosystem. Many fish that rely on the reef for camouflage would be exposed and eaten by predators. Many animals lay their eggs on the reefs. As their breeding grounds diminish their population will decline. Before the coral completely die they will be eroded and/or eaten (parrotfish). Human rely on the coral reef for food. Overall, less coral equals less food for us.