Lethal Seas and Coral Reefs

Coral Reefs

-Occur around islands or continental coastlines

-Ocean temp. >18 Degrees celcius (tropical areas)

-Home to 25% of all marine species

-Coral most abundant organisms

Why is there no coral reefs forming off the coastline of Ventura/Southern California?

Its is very cold for reefs to strive or survive in the water

What are the conditions needed for coral reef development?

-Warm Seawater (18 degrees to 30 degrees celcius)

-Sunlight for Zooxanthellae - Symbiotic, photosynthetic algae that supply nutrients and color to coral

-Strong waves or currents

-Clear seawater

-Normal Salinity

-Normal pH

-Hard subtrate

How are coral reefs formed?

As the volcanic island moves away from the hotspot, it becomes extinct and ceases to get larger. The extinct volcanic island is eroded away by wave action and begin to subside as the island and ocean plate cools & contracts. The upwards growth of coral towards sea level continues as islands subsides over time, this produces various types of reefs.

How much does coral grow below sea level?

Grows 5 to 10 meters below sea level.

What are the three types of coral reefs?

Fringing Reef - around an active volcanic island

Barrier Reef - Owns a lagoon & extinct volcanic island

Atoll - Lagoon in the center and island has subsided below sea level

What does Zooxanthellae do?

-Reef-building coral maintain mutualistic relationship with a type of algae called Zooxanthellae

-The algae provides photosynthetic products (oxygen and glucose) to the coral to aid in its survival, growth, and gives it color

-The algae receives unlimited carbon dioxide and nitrogenous wastes from the coral polyp in a competition - free setting. q

How does reproduction work with coral reef?

They use broadcast spawning

-The coral synchronize their spawning, usually once a year, with neighboring colonies by sensing a full moon, sunset and spawning chemicals

Environmental Issues for Coral Reef?

a. Sedimentation

b. Pollution from plastics and sunscreen, etc.

c.Coastal runoff from pesticides & fertilizers, etc.

d. Climate Change

e. Increasing acidity (lowering pH)

What is coral bleacing?

-Caused by a 1 degree celsius increase in temp. of ocean water or increase in acidity

-Corals expel Zooxanthellae & become bleached

-Starved of nutrients, corals die quickly

What is one of the few predators of coral reefs?

Crown of Thorns Starfish/Sea Star

-Sea eats coral polyps

-Outbreaks decimate reefs

-Can regenerate from body parts

-Possibly cause by overfishing predators

What are some of the few restoration projects?

Coral nurseries seen in Hawaii or Florida

Once grown to a certain size, the corals are individually attached by scuba divers to threatened reefs.