Coral Reefs and Lagoons

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Coral Reefs and Lagoons. Part I Section 5. What are corals?. Invertebrate marine animal A polyp that begins to form an exoskeleton CO 2 & Ca in the water to make calcium carbonate (CaCO 3 ) aka limestone Sessile – immobile Form colonies. Darwin-Dana-Daly Theory. Coral atolls - PowerPoint PPT Presentation

Text of Coral Reefs and Lagoons

Coral Reefs and Lagoons

Coral Reefs and LagoonsPart ISection 5 of thorns starfish


Invertebrate marine animalA polyp that begins to form an exoskeletonCO2 & Ca in the water to make calcium carbonate (CaCO3) aka limestoneSessile immobileForm coloniesWhat are corals?

Coral atolls1st proposed by Charles DarwinHMS Beagle (Nov 1835 Apr 1836)Supported and modified by 2 geologistsJames DalyReginald DanaDarwin-Dana-Daly Theory

1. Oceanic volcano emerges from sea surface and forms an islandColonized by reef-building coralsDarwin-Dana-Daly theory of coral atoll formation

2. Growth of corals forms a fringing reef around the islandFringing reef coral structure attached to the mainland or continental islandsIsland begins to sink slowlyCoral growth continuesDarwin-Dana-Daly theory of coral atoll formation

Fringing Reef

3. Island continues to sinkBarrier reef forms with lagoon around reef and islandBarrier reef - reef separated from a mainland or island shore by a deep channel or lagoon Darwin-Dana-Daly theory of coral atoll formation

4. Island eventually disappears below sea surfaceAtoll - consists of a ring of small islands Shallow lagoon in centerDarwin-Dana-Daly theory of coral atoll formation

Maldives Atoll

Atoll Formation

Fringing reef can take 10,000 years to form

Atolls up to 30 my

Coral tan and purple

10Data from deep drilling on coral atollsBikini Atoll (Pacific Ocean)As depth of corals increased, age of corals also increasedFossil corals dated 50 myo and found 1200 m deepGrown on underlying volcanic rockShallow corals found at deep depths!Evidence

Darwin (1842) produced 1st map of distribution of corals3 main types:Fringing barrier reefs, barrier reefs, atollsPhysiology of Coral

Conditions required:Temperature range =16C 35 COptimum range = 23 C - 25 CWater clarityClear water (less turbid) without siltSilt reduces light penetration which inhibits photosynthesis of symbiotic zooxanthellae in coral tissues (90% nutrients provided)Depth rapid growth occurs within 20 m from surfaceSalinitySubstrate surface on which plant/animals liveBasaltic rocks of seamountsDistribution of Corals, Zooxanthellae and FishBoundary for 20C Isotherms

Whats going on here?Shoreline protection from erosion - Dissipates/absorbs energy of wavesBenefits include protection ofCoastal propertiesEcosystemsCosts to provide breakwaters constructed structures for protection from erosionAnchorage of boats

Coral Benefits

Coral Gardens Fiji (Pacific Ocean)Egypt (Red Sea)Baja

Coral BeautyDue Friday!Read Marine Biology book pages 10-1Answer question 1 AND write bolded words with definitions!Dropbox it in complete sentence(s)Your NEW Oceanography textbooks are in!!!!!Homework!