1. Reefs Kinds of buildups Geographic distribution Reef requirements Community: diversity, environmental mediators, species of great affect The Sensitive Reef Reefs and Geologic Time

2. Reef requirements: 1. Coral reefs are rigid structures above the sea floor. Keep up with sea level or drown 2. Biologically mediated 3. Structure and environemtn

3. Reef requirements: 1. 3-D topography 2. Biological Origins and Mediation Created by organisms Organisms baffle, bind, accrete  modify environment 3. Structure and Environment

4. Reef requirements: 1. 3-D topography 2. Biologically mediated 3. A complex ecological and physical structure that exerts control on the environmet

5. Types of Reefs: Fringe Edge of landmass Continents, islands High energy from waves Small lagoon, if any

6. Types of Reefs: Barrier “Mature” fringe reef without landmass Kept up with sea level rise  appears far away from shore Large, ecologically rich lagoon between reef and land

7. Also formed from fringe reefs Ring structure from sunken island (subsidence or sea level rise) Reef with internal lagoon, no land mass Types of Reefs: Atoll

8. Types of Reefs: Patch Often in lagoon behind barrier, atoll Low energy environment Differentiated from surrounding biota by: 3-D topography Biological mediation Structure and environment

9. Types of Reefs: Manmade Accidental… (industry, pollutants, wrecks) …Or intentional

10. Tropical Reefs around the World

11. Biodiversity in Tropical Reefs

12. High light intensity: very low turbidity zooxanthellae in symbiosis with corals Warm T: between 20-30C Constant salinity Nutrients: upwelling, other input BUT: nutrient poor waters in reef Very tightly recycled Constant currents Tropical reef requirements

13. Communities 1 Very diverse, highest diversity community in the world Climax community High degree of niche specialization Resources very finely partitioned

14. Bafflers: corals, sponges Guilds that Mediate Environment

15. Bafflers: corals, sponges Binders: microbes, coralline algae, bryozoans Guilds that Mediate Environment

16. Bafflers: corals, sponges Binders: microbes, coralline algae, bryozoans Builders: corals Guilds that Mediate Environment

17. Bafflers: corals, sponges Binders: microbes, coralline algae, bryozoans Builders: corals Eroders: parrot fish, echinoids Guilds that Mediate Environment

18. Communities 2 Recruitment between reefs and within a reef Indo-Pacific reefs: highest diversity “Oldest” reef? Leftover from Tethys?

19. The Fragile Reef Reefs in very fragile balance Algae overgrowth and echinoids, other grazers Specialists: higher extinction possibility Interactions fairly tight Species of great effect, keystone species Physical factors: Sea-level rise T and global warming Nutrient input and algal blooms Saharan dust and fungus

20. Earliest buildups: Precambrian stromatolites Early Cambrian: Archaeocyathid reefs: 500MY Devonian: Tabulate, rugosa coral reefs Permian: Capitan sponge reef in TX Cretaceous: Various Cenozoic: coral reefs Geologic History of Reefs