Coral Reefs Cierra Maszkiewicz

What is Coral? Plant? Animal? Rock?

Coral is an animal!

Classification Phylum: Cnidaria Class: Anthozoa Radically symmetric Sessile animals

Structure Consists of three layers: 1. Outer epidermis 2. Mesoglea 3. Inner layer of cells lining the gastrovascular cavity, which carries out digestion Ring of tentacles that surround the mouth which helps capture food Tentacles contain stinging cells called nematocysts which further aid in capturing food Opens at only one end Made up of hundreds of thousands polyps Calcium carbonate is secreted to build a protective home for coral polyps, called a calyx

Stinging Cells Nematocysts help coral catch food They also help protect the coral When the cell is stimulated, it releases a sharp barb The barb will fire and catch the food and bring it back towards the mouth

Biology Zooxanthellae- single celled algae carry out photosynthesis in order for the coral polyp to receive nutrients Coral polyps have a symbiotic relationship with zooxanthellae Coral gives a protective home to the algae, and in return the algae supplies the coral with oxygen and helps it to remove wastes Zooxanthellae provides coral with organic products such as glucose, glycerol, and amino acids which are essential in producing protein, fats and carbohydrates Cyanobacteria provide soluble nitrates for coral reefs through nitrogen fixation Zooxanthellae Coral Polyps

Coral Reproduction Sexual reproduction is called spawning External fertilization It can start new colonies Sperm and eggs are released into the water column The fertilized egg is then called a planula The planula swims until it finds a safe place to live

Asexual Reproduction To reproduce coral can reproduce sexually or asexually Asexual reproduction in corals is called budding A baby polyp will begin growing off the adult When it is ready it will detach and live on its own This can not start new colonies, only help the old colony grow bigger

Coral Requirements Very specific habitats: Temperature:  F Depth: Less than 80 feet to 230 feet Salinity: Normal salt levels (35ppt) Light: Zooxanthellae need light to survive Sedimentation: Being covered with silt interferes with photosynthesis Desiccation (being exposed to air): The corals will die if exposed too long Coral likes areas with lots of waves: They are strong enough to withstand the pressure Freshwater means more food Waves remove silt

Types of Coral Reefs Fringing: grows close to shore Barrier: also grows close to shore but has a lagoon separating it from the shore Atoll: a ring of coral that surrounds a lagoon, often grows on a submerged mountain or volcano

Examples The Great Barrier Reef- Queensland, Australia; the largest coral reef system The Belize Barrier Reef- along the coast of Belize down to the Bay Islands of Honduras; second largest coral reef system The Red Sea Coral Reef- coast of Egypt and Saudi Arabia Pulley Ridge- Florida; deepest photosynthetic coral reef The New Caledonia Barrier Reef- length of about 1500km The Great Barrier Reef The Belize Barrier Reef

Importance of Coral Reefs Protection to coastlines Biodiversity Economic resources Natural beauty

Protection to Coastlines Absorb energy of ocean waves Reduce erosion of shoreline Storm damage Helps prevent flooding

Biodiversity The rainforests of the sea Genetic diversity Pharmaceuticals Home to 25% of all marine life

Economic Resources Fisheries for food Fisheries for jobs Brings in tourism Building materials Aquarium trade

Caribbean Reef Values (annual net benefits in 2000) Fisheries: $310 million Dive tourism: $2.1 billion Shoreline protection: $2.2 billion Total: $4.6 billion

Reefs Worldwide are Threatened 11% of reefs have been lost 16% of reefs severely damaged 60% of studied reefs threatened by human activities No pristine reefs left

Caribbean Reefs Declining 1970s: 50% coral cover Present: 10% coral cover 80% reduction in coral cover over last 30 years

Threats to Coral and Coral Reefs: 1) Natural 2) Anthropogenic

What are natural disturbances that affect corals and coral reefs? Hurricanes Tsunamis Volcanoes Earthquakes Predators & Competitors Bleaching Pathogens

Hurricanes Cause physical damage Smothering Freshwater poising Destruction of other ecosystems upon which coral reefs depend

Tsunamis Physical damage Erosion Possible disruption of reproduction and recruitment

Volcanoes Heat Smothering Sedimentation

Earthquakes Have little direct impacts Indirect impacts: Triggers tsunamis Costal landslides

Predators Crown of thorns starfish Snails Parrotfish Butterflyfish

Competitors Algae

Loss of zooxanthellae Causes higher than usual ocean temperature Sharp changes in salinity Bleaching

Pathogens Diseases on the rise 8 new pathogens Occurring at all depths More susceptible when stressed

What are anthropogenic disturbances that affect corals and coral reefs? Overfishing Development Mining and dredging Recreation

Overfishing Causes an ecological imbalance Destruction to coral reefs

Development Sediment causes smothering Freshwater input Pollutants (sewage, pesticides, fertilizer, heavy metals, pathogens)

Mining for Construction Materials and Dredging Destruction of reef structure Stirs up sediment

Recreation Anchors, boats, flippers Kills animal tissue Causes skeleton breakage

Global Climate Change Reduced reef building Increase in frequency and intensity of hurricanes Increases in bleaching Increased in disease

Fast Facts! One of the oldest ecosystems on Earth Largest living structure on Earth Without coral reefs, parts of Florida would be underwater Have been used to treat cancer, HIV, cardiovascular diseases along with ulcers Provide 375 billion dollars a year in goods and services Their limestone skeletons have been used for human bone grafts Coral is found in over 100 countries

How can you make a difference? Conserve water Help reduce pollution Dispose of your trash properly Spread the word!