Coral Reef Notes

Overarching Questions Should we permit tourists to visit the fragile coral reef environment?

Observations of a Coral Reef

Key Characteristics of a Coral Reef? Colorful Extremely Diverse Life Located in Warm Water USUALLY located in Clear Water Why? Water is Nutrient Poor How is there so much life in this area?

Interesting Facts about the Coral Reefs Though coral reefs cover leas than 1% of the Earth’s surface, over 25% of all marine fish species find their homes in coral reefs.  The average growth rate of a coral reef is less than 3 cm per year; hence it takes several years to form a large Coral is an animal related to jellyfish (A Cnidarian)

Anatomy of a Coral Reef (demo) -Coral is a Cnidarian -Reefs are made when each individual coral organism – or polyp – secretes a skeleton of calcium carbonate -Zooxanthallae (an algae/protist) will inhabit the Coral

Factors necessary for coral reef formation: Coral (animals) need: Zooxanthellae (algae)need: Salt water: 34-37 ppt Hard substrate to settle on as larvae Food Oxygen NOT A PLANT, A PROTIST Sunlight Nutrients (nitrogen) Warm temperature:~20ºC Clear water Carbon dioxide

Zooxanthellae (algae)need: Mutualism Coral (animals) need: Zooxanthellae (algae)need: Receives Food Receives Oxygen Receives protection Receives Carbon Dioxide

Importance of Coral Reefs to the Environment The Reefs built by corals provides homes for millions of different species Involved in nitrogen fixation  provides food to fish Photosynthesis of the Zooxanthallae  absorbs carbon Nursery for different organisms. Why?

Importance of Coral Reefs to Humans Coral reefs are widely used in the treatment of cancer, HIV, cardiovascular diseases and Asthma. Porous limestone skeletons of the corals have been used in grafting human bones. Important source for the fishing industry Protect coastlines from storm surges Stimulate economy through increasing tourism

Organisms of a Coral Reef

Corals

Leafy Sea Dragon and Weedy Sea Dragon

Clownfish

Blue Tangs

Parrot Fish -Eat Coral with their strong beaks -They cannot digest Coral, so they pass the crushed Coral  makes the nice white sand -Eat Coral with their strong beaks

Class Cephalopoda (Phylum Mollusca) “Head-Foot” Intelligent (largest centralized brain of all the invertebrates) Soft Bodied Sophisticated Eyes (but Colorblind)  Visual Predator Tentacles with suction cups Contain Chromatophorees (color changing cells) Contain Iridophores (reflective cells) Beak

Cuttlefish

Octopus

Squid

Squid External Anatomy

Squid Internal Anatomy Gills Gonads Pen (Cannot be seen in this picture)

Environmental Issues

The Ocean is a Carbon Sink pH Ocean acidification What does this mean? -The Ocean absorbs Carbon Dioxide Atmospheric CO2 Oceanic CO2 Temperature Coral Bleaching

What are the effects of too much CO2? Ocean Acidification Coral Bleaching

Ocean Acidification Lab

What is Ocean Acidification?

What is Ocean Acidification? Normal Conditions The Ocean is naturally Basic (pH ~8) Calcium Carbonate (CaCO3) present in the water and available for organisms to use for their shells and skeletons

What is Ocean Acidification? Atmospheric CO2 Oceanic CO2 pH Ocean acidification A decrease in Ocean pH means that there are more H+ ions  will react with the Carbonate Ions to form Bicarbonate INSTEAD of Calcium Carbonate

What do you observe?

Ocean Acidification  Decrease in Calcium Carbonate It DOES NOT mean that the ocean is so acidic that it is dissolving the shells of bivalves and skeleton of corals…yet. It DOES mean that there is not enough Calcium Carbonate for these shelled organisms to build their structures

What is Coral Bleaching? Atmospheric CO2 Oceanic CO2 Temperature Coral Bleaching An increase in CO2 (a greenhouse gas) causes an increase in temperature The increase in temperature is an environmental stressor for the Coral Other environmental Stressors: pH change and pollution

What do you observe?

What is Coral Bleaching? As Corals are stressed, they will start to expel and/or actively digest their zooxanthellae If the stress is intense, they Corals will expel all their zooxanthellae leading to the bleached look

Effects of Coral Bleaching The corals can survive a bleaching episode They are animals so they can still eat food to live BUT They are more vulnerable to diseases, infections, and mortality Zooxanthellae can be resorbed but will not survive long outside of the coral

Natural Threat: Crown of Thorn

Natural Threat: Crown of Thorns When balanced, the Crown of Thorns play an important role of consuming the fast growing coral; therefore, regulating the population and enabling slow growing corals to grow Cyclical outbreaks are natural but they have been happening more often than previously -possibly linked with the warmer waters because the sea star spawn during warmer seasons

Case Studies Human Impacts on Coral Reefs Crown of Thorns Impact