2. Sediments, salinity and pollution Fine sediment clouds H2O smothers coral Cuts down light for zooxanthellae Coral mucus can clean H2O (limited amount)

4. sediments

5. Sediments, Salinity, and Pollution Mining, logging, construction, dredging, increase sediments in H2O

6. Sediments, Salinity and Pollution Pesticides, industrial wastes, agricultural wastes, and fertilizers increase algae which blocks light from zooxanthellae = eutrophication

7. Water pollution

8. Eutrophication algal bloom

9. Satelite image of an algal bloom

10. Sediments, Salinity and Pollution Coral bleaching expels zooxanthellae

11. Bleaching Coral

14. Prebleach Postbleach

15. Primary Producers of Coral Reef Do photosynthesis to make food that feeds all other life- autotrophs Primary producers: 1. zooxanthellae 2. turf algae 3. Bacteria 4. coralline algae

16. Turf algae

18. Cyanobacteria/bluegreen algae

19. Coralline Algae

21. Hard Coral: competition Fast growers grow up and spread out to catch light and block others Attack other organisms with mesenterial filaments-digest them “Sweeper tentacles” with nematocysts sting neighbors

22. Plate Coral

24. Coral stinging each other

25. Soft coral competition Soft corals-have sharp needle spicules to discourage predation Can also move around some, slowly Contain toxic (bad tasting) chemicals released into H2O can kill hard coral

26. Soft Coral

29. Two hypotheses about competition Lottery hypothesis= feeding habits /life styles overlap and competition is strong. Survival is luck Deterministic hypothesis= each organism has its own niche. Most accepted

30. Definitions Ecological niche= what a species eats where it lives, how it behaves and all other aspects of its lifestyle. “job” or role in a community Competitive exclusion= one species out competes the other. No two species can occupy the same niche

31. Predation on corals In what way is coral predation like plant grazing by herbivores? “predators” graze down the coral without killing it off entirely.

32. The affect predation has on the number and type of coral Fast growing corals are held in check by predation (butterfly-fish,coral-eating snails) Crown-of-thorns sea star eats only certain corals

33. Herbivores/grazers on the reef Parrot fish Damsel fish Sea urchins Surgeon fish Snails Crustaceans

34. Parrot Fish

35. “Grazing” Fish

36. What if the herbivores/ grazers were removed? Grazers control algae growth  algae overgrows reef, kills coral If pollution is added (nutrients) algae grows explosively = eutrophication chokes out everything See eutrophication