1. Chapter 14 Part 1 Coral Reefs Classification Biology Diversity Feeding/Nutrition

2. Coral Classification Domain: Eukaryota Kingdom: Animalia
Phylum: Cnidaria (Hatschek, 1888)
Class: Anthozoa (Ehrenberg, 1831)

3. Scleractinian Corals Calcium carbonate skeleton (CaCO3) Polyps
Symbiodinium sp. (zooxanthellae)
Hermatypic –
Contain Symbiodinium
Reef-building
Ahermatypic
Most do not contain Symbiodinium
Not reef-building

4. Coral Classification

6. Coral Biology
coenosarc
Figure Cutaway view of one of the polyps in a coral colony and of the calcium carbonate skeleton underneath.

7. Coral Biology Radial symmetry One opening (mouth)
Gastrodermis – tissue lining stomach
Septum – increase stomach lining area and contain reproductive cells
Basal plate - calciferous ring with 6 supporting radial ridges. The ridges grow vertically and project into the base of the polyp.
This drawing depicts the basic anatomy of a hard coral polyp. Artwork Credit: NOAA/Gini Kennedy

8. Calcium Carbonate Skeletons
CO2 + H20  H2CO3
(carbonic acid – weak acid)
H2CO3  H+ + HCO3-
(carbonate ion)
H+ ion helps to neutralize by combining with OH- to form H20
Carbonate ion will also:
HCO3-  H+ + CO32- (bicarbonate ion)
Ca2+ + CO32-  CaCO3
TAKES ENERGY – Where does it come from?

9. Coral Polyps
Most corals are made up of hundreds to hundreds of thousands of individual coral polyps like these. The tissue is only millimeters thick.
Night
Day

10. Symbiodinium (zooxanthellae) are found in the gastrodermal layer of tissue in the coral at densities greater than 1 million per square inch
Photoprotections are necessary for all photosynthetic organisms including Symbiodinium. There are a diverse array of ways these organisms protect themselves from excess light energy especially in shallow ocean waters. Many people here have done groundbreaking work on photoprotections in Symbiodinium and today I’m going to build on the knowledge base they have created.
Porites astreoides
Symbiodinium photo by S. R. Santos

11. Symbiodinium Classification
Domain: Eukaryota Kingdom: Chromalveolata Superphylum: Alveolata Phylum: Dinoflagellata Class: Dinophyceae Order: Suessiales Family: Blastodiniaceae Genus: Symbiodinium
(Freudenthal, 1970)

12. Symbiodinium Endosymbionts of cnidarians and giant clams
Provide corals up to 100% of energy for survival and reef-building
Corals provide wastes that Symbiodinium uses for photosynthesis.
Symbiodinium provides corals products of photosynthesis for food
Acquired by corals
Ingestion by planula
Transmission from mother to daughter colony through asexual reproduction
Ingestion by coral especially after “bleaching”

13. Symbiodinium Diversity
Large culture collection, so opportunities for experiments.

14. Symbiodinium ecological diversity
LaJeunesse, 2001

15. Typical Coral Growth Forms

16. Caribbean Corals Acropora palmata – A3 Porites astereoides – A4a
Montastrea faveolata – B1
Gorgonia ventalina –B1
Porites furcata – A4, B1, C4
Siderastrea siderea – C3 or B5a

17. Acropora formosa and Porites sp.
Indo-Pacific Corals
Platygyra sp.
Acropora formosa and Porites sp.
Acropora formosa
Herpolitha limax
Acropora hyacinthus
Acropora humilis
Acropora sp. mix
Porites sp.

18. Acropora sp. in the Pacific
Reef Building Corals: Pacific

19. Coral Nutrition and Feeding

20. Coral Nutrition and Feeding
Mesenterial filaments secrete digestive enzymes, corals can also use mucus nets, or absorb DOM from the water

21. Coral Nutrition and Feeding

22. One of worst bleaching events in history
Love-Hate Relationship with Sunlight
Use of sunlight
Necessary for photosynthesis by Symbiodinium
Must protect itself against excess sunlight to avoid “bleaching,” or more accurately, “paling” of Symbiodinium cells
Coral skeleton scatters light to increase absorption when fewer pigments available (Enriquez et al. 2005)
GBR
One of worst bleaching events in history

23. Love-Hate Relationship with Sunlight
Protections against too much sunlight
Photoprotection
Pigments, pathways of photosynthesis, others
Coral pigments
Movement of Symbiodinium cells
Diversity of Symbiodinum cells on a single colony
Kemp et al 2008

24. Coral Bleaching Global climate change and coral bleaching
Warmer oceans + high light
= stressed Symbiodinium and corals
AND possible death of corals from loss of Symbiodinium
lh3.ggpht.com

25. Coral bleaching video

26. Coral bleaching
42% of coral cover of GBR lost