Part II Section 5

 What is a coral? What is a coral?  Healthy corals accumulate CaCO 3 at rate of 3-15 meters in 1000 years

 Predation  Crown-of-thorns starfish (Acanthaster planci): coral predator in Indo-Pacific Reefs  Time lag = cause/effect (max. # of predators as coral level falls)  Removal of the starfish Removal of the starfish Click video

 Storm Damage ◦ Hurricanes or tropical storms ◦ Physical breakage of corals ◦ Abrasive sediments  Hurricane Hattie (1961 – Cat 5) destroyed 43 km of the British Honduras barrier reef ◦ Recovery – 25 to 100 years

 Exposure to air ◦ Corals dry out ◦ Overheat

 Reef erosion = shores/coastal properties are exposed to damages from waves  Artificial reefs: human-made structures = concrete/stone blocks, sacks filled with sand or shipwrecks (sunken ships) ◦ Colonized by algae, corals and fish ◦ Used as submerged breakwater  Dissipate wave energy Click

 Prevents erosion of land  Anchorage/protection for harbors  New habitats  Increase fishing areas  Tourism – snorkeling/diving

 USS Oriskany (2006)

 Geomorphology – study of landforms and processes involved in shaping them

 Shows growth and geological history of reef  Carbon Dating – age of coral sample ◦ As corals grow, carbon (from carbon dioxide) is deposited in their skeleton as CaCO 3 ◦ 14C carbon slowly decays to 12C  Proportion of 14C to 12C estimates age of coral  Can estimate age up to 50,000 years old

 Deep drilling – cores of material to identify corals and estimate growth rate ◦ Have ‘bands’ just like tree rings (give age)  Evidence of growth rate due to environmental conditions like temperature or nutrient availability

 Growth up to 20m deep  Fossil corals found at 1200 m is evidence of subsidence (caving in and sinking of land area) ◦ New coral grow on top of old as reef gradually sinks  Fossil corals found above sea level ◦ Evidence of changes in sea level  Mexico – sea level changes between ice ages

 Access this link: ◦ rals/ rals/ ◦ Answer Questions passed out to you. ◦ Due Monday, April 8 th  Read Marine Biology book pages ◦ Answer question 1 AND write bolded words with definitions!

 Climate Close-up (paleoclimatology) Climate Close-up  Coral Reefs Coral Reefs