Function of coral reef
ecosystem
Azad Uddin Sojib
Oceanography
Session: 2016-17
Enroll: ASH1718010M
Noakhali Science And Technology University

Preamble:
Coral reefs are the most diverse of all marine ecosystems. They teem with life, with
perhaps one quarter of all ocean species depending on reefs for food and shelter. This is a
remarkable statistic when you consider that reefs cover just a tiny fraction (less than one percent) of
the earth’s surface and less than two percent of the ocean bottom. Because they are so diverse,
coral reefs are often called the rainforests of the sea.
Coral reefs are also very important to people. The value of coral reefs has been estimated at 30 billion U.S.
dollars and perhaps as much as 172 billion U.S. dollars each year, providing food, protection of shorelines,
jobs based on tourism, and even medicines.

Ecosystem function:
Ecosystem function' is the technical term used in the Framework to define the biological,
geochemical and physical processes and components that take place or occur within
an ecosystem. Sometimes, ecosystem functions are called ecological processes.
Coral reef ecosystems:
Coral reef ecosystems" as large, interactive areas of coral reef development containing
many individual reefs and associated habitats (e.g., seagrass meadows). These ecosystem
extends from the shorelines of tropical islands and coasts to the deep blue waters of the open
sea, and includes all the marine life within the area as well as the non-living parts of their
environment.

The health, abundance and diversity of the organisms that make up a
coral reef is directly linked to the surrounding terrestrial and marine environments.
Mangrove forests and seagrass beds are two of the most important facets of the
greater coral reef ecosystem. Mangroves are salt-tolerant trees that grow along
tropical and sub-tropical coasts. Their complex root systems help stabilize the
shore line, while filtering pollutants and producing nutrients. Their submerged roots
and detritus provide nursery, breeding, and feeding grounds for invertebrates, fish,
birds, and other marine life. Many of the animals raised in mangroves migrate to
coral reefs for food, spawning and habitat.
Seagrasses are flowering plants that often form meadows between
mangrove habitats and coral reefs. They form the foundation of many food webs,
providing nutrients for everything from sea urchins and snails to sea turtles and
manatees. Seagrass also provides protection and shelter for commercially valuable
species such as stone crabs, snappers and lobsters. Additionally, they filter the
water column, prevent seabed erosion, and release oxygen essential for most
marine life.

Formation/types of Coral Reef:
There are three formation of coral reefs:
1. Fringing Reefs,
2. Barrier Reefs,
3. Atolls.
1.Fringing Reef:
 Grow directly from a shore.
 There is no lagoon between the reef and shore.
 Most common of the three major types of coral reefs.
 Simplest and island.

 It’s develop near the shore in tropical waters.
 It’s develop as narrow strips along the shore.
Greater Caribbean region
2.Barrier reef
> Extensive linear reef complexes, that parallel a
shore,
> separated from a lagoon.
> sinking island.
>world’s largest coral reef.
> Over 1257 miles long.
> Off the northeast coast of Australia.
> Only grows about one inch per year.
> e.g.: Great Barrier Reef, New Caledonia's NE
coast.

3. Atoll reef:
> Its surrounding a large (and often deep) central lagoon.
> Most atolls occur in mid-ocean.
> Island below sea level
> E.g.: French Polynesia, the Caroline and Marshall Islands, Micronesia, and the
Cook Islands.
Factors of coral reefs:
Abiotic factors:
# Temperature -26 to 30 degree Celsius.
# Salinity -34/35ppt.
# Light penetration.
# Sunlight –need to photic/neritic zone.
# Water density.
# Buoyancy or turbidity.
# Sediments.
# dissolved oxygen (DO)
# pH.

1.Biotic factors:
Biotic factors of a coral reef ecosystem would
include the living coral polyps and associated zooxanthellae (algae).
Additionally, fish, aquatic plants, and other organisms living in and
around the reef would be considered biotic factors.
Four limiting factors of coral reefs:
1) Pollution
2) Disease
3) Over-fishing
4) Temperature

1.Pollution:
The pollution is from sediments, nutrients, and a variety of land based activities. Those
land activities are then transported over time into the water. Pollution has increased
globally due to human activity and their pollution.
2.Disease:
there is a lot of different diseases in coral reefs. They are mostly cause by bacteria. Coral
reefs are very sensitive. Ex: The Black Band Disease is caused by a bacteria called
Phormidium Corallyticum. The symptoms of the Black Band Disease is black stuff moving
across the coral reefs. Other symptoms are the colonies will all be killed within months.

3.Over-fishing:
Coral reefs are being damaged from human activity of fishing. It can affect the reefs
biodiversity and its balance. When people fish for food can also lead to high levels of algal
growth. Algal growth is unicellular organisms that are classified as plants, sometime
accruing in coral reefs, fresh water, and salt water.
4.Temperature:
Temperature is the most important part to coral reefs. It is responsible for the horizontal
spatial distribution of coral reefs. Most of coral reef temperatures are between 16 and 30
degrees Celsius (61 to 86 degrees Fahrenheit). If it gets to hot or too cold it could be
dangerous for the coral reefs and living things around them like animals.

Epilogue:
Coral reefs are also very important to people. The value of coral reefs has
been estimated at 30 billion U.S. dollars and perhaps as much as 172
billion U.S. dollars each year, providing food, protection of shorelines,
jobs based on tourism, and even medicines