1. Coral Reefs & Lagoons Part 2
AICE Marine Science
Unit 5

2. Difference between shallow & deep corals:
Lack zooxanthellae
White
Energy ONLY from filter feeding w/ stinging tentacles
Grow slower
Habitat: Anywhere (do not need clear, shallow, sunlit water)
Shallow:
Symbiotic w/ zooxanthellae
Colorful
Energy from zooxanthellae & from filter feeding w/ stinging tentacles
Grow faster
Habitat: shallow, clear, warm waters (tropics)

3. Anatomy of a coral reef:
Reef front/Fore reef/Outer reef: Ocean side; receives some wave energy
Reef crest: Highest point; receives full impact of wave
Reef flat/Inner reef/Back reef: Leeward/land side; descends into lagoon; may have seagrasses

4. Reef structure:

5. Benefits of Coral Reefs
Coastal protection from waves & storms
Medicine (from calcium carbonate coral skeletons, sponges, & other corals; anti-cancer, anti-inflammatory, anti-tuberculosis, anti-viral, anti-malarial)
Food
Habitat for many other organisms
$ from tourism
Benefits of Coral Reefs

6. Coastal Protection: Coastal properties Inland ecosystems
Reduce the cost of providing breakwaters
Reduced wave action provides safer anchorage for boats (on the leeward side)
The Breakers, Palm Beach
Singer Island

7. Breakwaters & Jetties: coastal erosion control

8. Dangers to Coral Reefs:
Sedimentation
Blast Fishing!
Crown of Thorns loves to forage on coral polyps
Trash/Pollution
Discarded fishing nets
Humans’ Touch
Discarded nets & pollution
Anchors
Coral Bleaching

9. Coral Reef Inhabitants

10. Growth Rate:
Healthy reefs accumulate CaCO3 at rates between 3-15m/1000yrs

11. Factors that affect growth rate:
Overfishing of herbivorous fishes
Ocean temperature
Salinity
Low inorganic nutrients
Solar radiation/Water transparency
Sedimentation
Can you think of any others?

12. Reef Erosion
Predation—Herbivores feeding directly on the coral or the zooxanthellae
Bioerosion—Predation (above) or change in the substrate (top picture, right)
Boat anchors
Storms
Exposure to air

13. Loss of substrate 

14. Coral Bleaching: Caused by death of zooxanthellae (from warming waters

15. Reconstructing the History of Coral Reefs
Drilling: core samples; visible layers help to determine age (think of rings in a tree)
Geomorphologic analysis: studying the shape; fringing, barrier, or atoll
Carbon dating: comparing the proportions of carbon isotopes: 12C & 14C (14C taken up by corals decays to 12C) helps determine the age (14C half-life is 5,730 years)

16. Artificial Reefs: Airplanes Ships Obsolete oil rigs Boats Bridges
Tyres
Junked appliances
Ballistic missiles
Subway cars
Ships
Boats
Concrete
Reef Balls
Steel boxes
Military equipment (incl. tanks)
Docks

17. Artificial Reefs Have the same benefits of living coral reefs:
Habitat for other organisms (& growth site of new coral polyps)
Coastline protection

18. Artificial Reefs (sinking of USS Oriskany in 2006)

20. An Artificial Reef (in the making)
400 Sculptures
Cancun, Mexico