TABLE OF CONTENT
coral reef ecology
adaptations to coral reef
types of ecology
CORAL REEF ECOLOGY
Coral reefs are often referred as one of the most marvellous creations of nature. It is also
one of the oldest types of ecosystems with a huge variety of living things and non living
things. Although coral reefs account for about around one percent only of the ocean floor, it
is home to at least twenty five percent of the whole marine life. Most reefs are normally
located in clear tropic oceans with a depth not exceeding forty five metres as corals depend
on sunlight for their survival. The largest reef known to man is 'the great barrier reef'
located off the coast of north east of Australia.
Corals are in reality clusters of thousands of tiny animals called "coral polyps" and not rocks
or plants as it is believed generally. These tiny organisms produces calcium carbonate to
form a protective layer around them. This layer is the first step in reef building, later on
these fragments of corals grow wider and merge to form a fringing reef which is followed by
a barrier reef and the last stage is an atoll as shown in the picture below.
the firststage is a fringingbarrieraroundthe island.
the secondstage is a barrierreef aroundthe
perimeterof the islandwhichispartiallysubmerged
the thirdstage isthe formationof an atoll withthe
ADAPTATION TO REEF
Coral reefs are complex and densely populated ecosystemwith a huge biodiversty. Among the
inhabitants, the various types of fish stand out as they are not like normal ocean dwellers.
This is due to the adaptation they had to undergo so as to be able to live easily in the reefs.
One such adaptation is their flat body, this is so because the reef fish has to operate in
rather confined spaces, between narrow canals or through the complex structure of the
reef. Another reason why they have a flattened shape is for a better manoeuvrability and also
the ability to dart or change directions swiftly, most of the time this is performed to escape from
predators by hiding around the corals or dodge their attacks. Many reef fish, such as the
butterflyfish andangelfish,have evolvedbodieswhichare flat.Theirfinsare alsodesignedaccording
the thin body to maximise manoeuvrability.
the figure above shows us the difference stated between an angelfish, a reef fish and a
bluefin tuna, an open sea fish.
Reef fishes have another unique feature and it is their live and colourful stripes or patterns
unlike open water fishes with silver shades. The patterns and the lively colours also have
their use apart from making the reef habitants beautiful. This is used by the small fishes as a
means of defence to warn their predators that they are poisonous or contain toxic spines
some examples are: clownfish, angelfish and the royal gramma. In some cases the
coloration of the animal can provide a good camouflage provided that it is in the right
background for example, a lionfish resting among the corals.
AN EXAMPLE OF CAMOUFLAGE OF A
Camouflage as stated above is used by fish who are down the food chain. With time, even
the predatory fish have adopted this technique of blending into the nature to catch their
food. they are called 'ambush predators' as they stay still and suddenly they attack their
prey. Some types of ambush predators are namely: frogfish, scorpionfish and the grouper.
Another adaptation the reef dwellers had to adopt new ways of feeding themselves. Some
species of marine animal makes use of the coral reef as a trap for others such as the giant
moray eel who is seen in cooperative hunting with loepard groupers.
In a coral reef, there is more than one food chain for most organisms as they eat more than
one kind of food or are eaten by more than one type of predator. A food web is then
established with the given data with the aim to distinguish the levels of the myriad species
living in the reef. The trophic level is usually classified by four levels which are:
level 1-primary producers(plants)
examples would be :zooxanthellae and phytoplankton who produces their own food
level 2-primary consumers(herbivores)
examples would be :corals and small inverebrates which feeds on zooxanthellae only
The grouperusingcamouflage to
catch his food.
level 3-secondary consumers(carnivores)
examples would be :butterfly fish which feeds on coral polyps and damselfish which feeds
on algae and other plants.
level 4-tertiary consumers(apex predators)
examples would be :barracuda and reef shark who in turn feeds on butterfly fish and other
coral dweller smaller than them.
Biomass transfer efficiency
The diagram above shows us the energy pyramid with respect to the food chain. The ones at
the bottom hold more energy than those at the peak. This is because as the trophic levels
are ascended the energy is divided by a factor of 10.
e.g: a plant processes 1% of chemical energy, this is then processed by a herbivore fish
whose energy output would be 0.1% followed by the carnivore's fish energy at 0.01% and
finally the apex predator obtains only 0.001% of the initial energy processed.
Biochemical cycles in coral reefs
1 carbon cycle
Sources of carbon cycle is as follows:
cellular respiration-is a metabolic process where organisms releases energy.Carbon
dioxide is produced and circulated into the body
plants such as algae and mangroves uses carbon for photosynthesis
external skeleton of corals composed of calcium carbonate (a compound of carbon)
2 nitrogen cycle
sources of nitrogen cycle is as follows:
1. nitrogen is trapped in soil.
2. plants take up nitrogen from soil.
3. fish eats plant and retains the nitrogen.
4. carnivore fish eats initial fish.
5. secondary consumer dies and decomposer starts breaking the body.
6. nitrogen is released back in the ecosystem.
Types of ecology
1 Organismal ecology focuses mainly on the adherence of the organism to it environment in
morphological, physiological and behavioral ways.
2 Population ecology concerns only one specie and sees how it interacts with its
3 Community ecology is the interactions between groups of species in an area.
4 Ecosystem ecology is the study of how biotic and abiotic components interact within an
5 Global ecology is the study of all types of ecology in a world scale where all ecosystems
interacts with each other.
illustration of 'types of ecology'.