Coral can be found throughout the oceans, although the organisms that build tropical (biotic) reefs only grow between 70-85oF (21-29oC).
Most corals exist between the Tropic of Cancer and the Tropic of Capricorn
Corals exist in deep cold water to shallow, tropical water.
Can be found at depths over 300ft (90m)
Reef building corals grow at depths shallower than 230ft (70m)
The most vibrant reefs, humans dive and snorkel on, exist no deeper than 60-90ft (18-27m)
They need salt water to survive, so they do not grow near rivers or fresh water runoff
Coral is actually a living animal, or several species living together symbiotically (see post)
Corals can exist as individual polyps or in colonies that contain hundreds of polyps (brain coral, is actually many polyps 1-3mm in diameter)
As much as 90% of photosynthetic energy is transferred from the zooxanthellae to the host coral
Coral can reproduce both sexually and asexually
Sexually: most common, done by broadcast spawning or brooding
Asexually: by creating a new coral from a broken piece
Coral reefs are built by millions of coral polyps (they look like upside-down jellyfish)
Over time the use of excess carbon dioxide in the water turn the polyps into limestone, creating island chains like The Bahamas
How Many Types of Reefs are There? Seven.
Apron & Fringe Reefs: reach down and out from shore (Apron reefs are not as steep)
Barrier Reefs: separated from the shore by lagoons
Atoll Reefs: surrounds a lagoon in a circular, or uninterrupted way, with no island in the middle
Patch & Ribbon Reefs: Are self-contained, isolated reefs that are not necessarily near land
Table Reef: A small, isolated reef with a flat top
Scientific Name: Scleractinia (also called Stony Corals)
Similar to sea anemones but generate a hard
First appeared: Middle Triassic Era
Colonial corals: shallow, clear tropical waters, world’s primary reef builders
Solitary corals: found in all regions of the ocean, do not build reefs (some live in polar
waters, or below the photic zone 6000m below the surface)
Scientific name: Alcyonacea (include sea fans and sea
Do not produce calcium carbonate skeletons, and
therefore are not reef-building corals, nor to they lay a
foundation for future corals
These corals get their structural support from tiny, spiny
skeletal sclerites, or grainy texture that deters predators
Thrive in nutrient rich waters, with less light
Almost all soft corals use zooxanthellae as a major source or energy
Coral reefs provide shelter for a wide variety of marine life
They are a valuable source of food, and nutrients for humans and the ocean
Coral reefs produce carbon dioxide
How much of our Food is Supplied by Coral Reefs? The Billion-Dollar Industry:
Fish that would call coral reef home if they could talk account a food source for over a billion people worldwide (many of whom live far from where the fish are caught)
A staggering half of all the federally managed fisheries in the US depend on coral reefs as a habitat for a portion of their life cycle
The commercial value US fisheries gain from coral reefs is estimated to be over $100 million
What have we gained from Reefs? Medicine:
The chemical compounds used for defense found in many coral reef species, like sponges and nudibranchs, have the potential for new pharmaceutical breakthroughs.
Coral reef species have helped in the development of new medicines for: easing labour, treating cancer, arthritis, ulcers, asthma, bacterial infections, heart disease, viruses and disease.
Also used as sources of nutritional supplements and enzymes and has also been used in cosmetic research.
We Love to Relax and Explore Coral Reefs. Tourism:
Millions of snorkelers and divers visit coral reefs every year to delve into an alien universe
Even more tourists visit islands, resorts and beaches protected by reefs
Tourist-driven economies receive millions of dollars from visitors to coral reef areas, from diving, fishing trips, hoteliers, restaurants, surfers, and a plethora of other businesses that encompass coral reef communities.
Reef-based recreational fisheries generate over $100 million/year in the US alone
It has been estimated, the total worldwide value of coral-reef based recreation and tourism is at $10 billion!
Indonesia is looking at spending over $100 million on research and implementation of sustainable coral reefs.
MPAs are being established around the world, allowing sustainable fishing that can be managed, and important habitants will be conserved and protected
Laws for MPAs are being molded after the laws for provincial and national parks
The aquarium fish trade has accounted for massive decline in reef species numbers, especially in Asia. Laws to make this trade more responsible and sustainable are being implemented through education in third-world countries to limit overfishing
Some scientists are attempted to grow coral, by placing artificial reefs (like a properly sunken boat) or by harvesting corals and responsibly planting them elsewhere
Coral Reefs are One of the most Delicate Ecosystems on the Planet. What are Coral Reefs Susceptible to?
Coral reefs are extremely sensitive to light, temperature change, overfishing, damaging fishing practices, pollution, excess sediment from development, acidification, pH changes and changes in hormone levels in surrounding water.
El Niño and El Niña years are natural factors that influence coral bleaching
Human activity is the greatest threats to coral reefs, the destruction of mangrove forests due to tourism and development, which allows silt out to sea ultimately suffocating the coral and block out sunlight.
The hormones and waste we discharge untreated into the water affects every link of a coral reef ecosystem.
In The Philippines and Indonesia they use cyanide to stun fish on coral reefs, but it damages invaluable corals and species – suffering a 90% mortality rate several weeks after cyanide exposure
Some fishermen use dynamite to blast fish from crevasses, others use crowbars to scare out fish, damaging delicate coral that takes thousands of years to grow.