Corals are in fact animals, even
though they may exhibit some of the characteristics of plants and are often
mistaken for rocks. In scientific classification, corals fall under the phylum
Cnidaria and the class Anthozoa. They are relatives of jellyfish and anemones.
Coral reefs are the most diverse
and beautiful of all marine habitats. Coral Reefs are the "Rainforests" of the
ocean. Reefs are ecologically important ecosystems and have a high biodiversity
that serves as a storage bank of rich genetic resources. They are a source of
food and medicine, and they protect the coast from wave erosion.
Home to more than 1 million diverse aquatic species, including
thousands of fish species
Income: Billions of dollars and millions of jobs in more than 100
countries around the world Food: For commercial fishing enterprises and for people living
near coral reefs, especially on small islands Protection: A natural barrier protecting coastal cities,
communities, and beaches Medicine: Potential treatments for many of the world's most
prevalent and dangerous illnesses and diseases
Corals are marine
animals related to jellyfish and anemones. Both colonial and solitary corals
catch plankton (microscopic plants and animals) and other suspended food
particles with arm-like tentacles, which feed a centrally located mouth. Most
hard corals also host symbiotic algae, a long-standing and successful
partnership. These algae provide them with an additional food source through
photosynthesis. Coral reefs are formed by corals that secrete hard calcareous
(aragonite) exoskeletons, giving them structural rigidity. These colonial “hard
corals” form elaborate finger-shaped, branching, or moundshaped structures and
can create masses of limestone that stretch for tens or even hundreds of miles.
Clean, clear water
is essential to their health. Once coral larvae settle on a hard substrate and
become established, colonies can arise if conditions are suitable for growth.
Given enough time, coral colonies become thickets. As coral thickets build
upward on the skeletal remains of older colonies, a reef is established. Today,
richly diverse coral reefs are found in the tropics along coastlines, on the
margins of volcanic islands, and as isolated coral atolls.
Tropical coral reefs can be
found in a zone between 30° north and 30° south of the equator. They
don't grow deeper than 50 meters and the optimum water temperature is
25-27°C degrees, with some species able to live in colder waters up to
Cold water corals live in
higher latitudes as deep as 2000 meters and with water temperatures
4°C. These corals are stony corals but they don't necessary host a
zooxanthella. Deep water corals don't form reefs but they form
aggregation called banks or bioherms. Deep sea corals also referred to
as mounds, which describes the calcium carbonate skeleton which left
behind as the coral grows.
Cold water corals live in nutrient rich water and feed on zooplankton.
They are also form a diverse ecosystem hosting fish species and
invertebrates. These corals are much more vulnerable as they grow
slower and takes more time to recover. They mainly threatened by human
activity such as trawling and long line fishing. Also laying of
submarine communication cables can cause huge damage.
There are two
distinct regions in which tropical coral reefs are primarily distributed: the
Wider Caribbean (Atlantic Ocean) and the Indo-Pacific (from East Africa and the
Red Sea to the Central Pacific Ocean).
The diversity of
coral is far greater in the Indo-Pacific, particularly around Indonesia, the
Philippines, and Papua New Guinea. Many other groups of marine fauna show
similar patterns, with a much greater diversity in the Indo-Pacific region.
possess a smaller number of species the corals of the Atlantic are still
unique, with few common species between the two regions .
The majority of reef building corals are found within tropical and subtropical
waters. These typically occur between 300 north and 300
south latitudes. The red dots on this map show the location of major stony coral
reefs of the world. Credit:NOAA
Coral Science from Outer Space to Inner Space
Coral reefs are
found in about 100 countries. Coral Reefs are home to over 25 percent of all
marine life and are among the world's most fragile and endangered ecosystems. In
the last few decades over 35 million acres of Coral Reefs have been obliterated.
Reefs off of 93 countries have been damaged . When corals are stressed by high
temperature, ultraviolet light or other environmental changes, they lose their
symbiotic algal cells, and appear white (the white skeleton is actually visible
through the transparent tissue). Depending on the intensity and duration of the
stress, the corals may recover or die.
If the present rate of destruction continues, 70% of the world's coral reefs
will be destroyed within the next few decades.
Climate change will
destroy the world's great coral reefs within a century, according to a report by
German and Australian marine scientists.Researchers say governments must take
action now to reduce the emissions of gases such as carbon dioxide, which are
thought to be behind a rise in average global temperatures.
A slight rise
in temperature can bleach coral like this
The scientists combined their coral
expertise with the latest climate models to project what is likely to
happen to the world's greatest reefs if global warming remains unchecked.
Their study suggests the unique marine environments will increasingly
become victim to a process known as coral bleaching.
A slight rise in
maximum water temperatures - only one to two degrees - can stress the corals.
This causes them to expel the microscopic organisms, known as zooxanthellae,
which color their tissues and provide them with essential nutrients.
If the zooxanthellae
do not return, the corals will die. In 1998 every reef system in the world's
tropical oceans were affected by some degree of bleaching. The report says the
frequency and intensity of bleaching is set to rise.
The report's lead author is Professor Ove Hoegh-Guldberg, an expert on coral
bleaching at Sydney University. Coral reefs could be eliminated from most areas
of the world by 2100, Even the world's largest reef - the Great Barrier Reef off
Australia - could be dead within 30 years unless measures are taken now to slow
Coral Reef Facts
Coral reefs are among the oldest ecosystems on Earth.
Coral reefs are the largest living structure on the planet.
Although coral reefs cover less than 1% of the Earth’s surface, they are
home to 25% of all marine fish species.
500 million people rely on coral reefs for their food and livelihoods.
Coral reefs form natural barriers that protect nearby shorelines from the
eroding forces of the sea, thereby protecting coastal dwellings,
agricultural land and beaches.
Without the existence of coral reefs, parts of Florida would be under water.
Coral reefs have been used in the treatment of cancer, HIV, cardiovascular
diseases and ulcers.
Corals' porous limestone skeletons have been used for human bone grafts.
It is estimated that coral reefs provide $375 billion per year around the
world in goods and services.
If the present rate of destruction continues, 70% of the world's coral reefs
will be destroyed by the year 2050.
Reef Relief founders Craig and DeeVon Quirolo retired from the grassroots
organization last July, only to begin an effort to provide an online resource on
coral reefs. Their new website provides all the award-winning educational tools,
grassroots strategies, project reports and images of coral reefs assembled
during their work over the past 23 years in the Florida Keys and throughout the
Caribbean protecting coral reefs. You can find it at
credit: NOAA, NASA, Reef Check,
UNEP, Reef Relief, Australian Government, University of Texas, Great
Barrier Reef Marine Park Authority, Coral Reef Alliance
Data compiled from The
British Antarctic Study, NASA, Environment Canada, UNEP, EPA and
other sources as stated and credited Researched by Charles
Welch-Updated daily This Website is a project of the The Ozooe Hole