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Ref No: 1375

Task 1

1.1 Formation & Composition of Coral Reef

Coral reefs are vibrant centers of rich and teeming biodiversity found underwater that are found in sub-tropical and tropical waters all over the world. The composition and occurrence of coral reefs vary from one place to another.

The reef ecosystem recycles nutrients on its own to sustain life of its living organisms. Corals come under the broad category of Anthozoa, a class of Cnidarian.Extreme Environments. The structure of hermatypic corals (reef building corals) resembles that of polyp as they have external skeleton that produces coral reefs (Matysik, Al-Ramadan & Riding, 2015).

The formation of coral reefs initiates when coral larvae that are swimming freely, attach themselves to surfaces all along the edges of islands. When these corals expand and grow, these can take form of an atoll, barrier or fringing.

Atolls reefs have a central lagoon and are oval or circular in shape. Barrier reefs border shorelines but are detached from land masses by deep water. Lastly, fringing reefs form borders around islands and shorelines and project outwards.

Atoll, barrier and fringing coral reefs share similar bio-geographic factors such as creation of species, algae, vertical and horizontal corals through suspended sediments, temperature, light, current strength, wave, depth and bottom topography.

1.2 Coral Reef Species & Organisms, Zonation & Diversity, Disturbance, Destruction, Symbiosis and Threats

The main groups under corals are soft corals (octocorals), stony corals (scleractinian) and gorgonians (sea whips, sea fans and sea pens).

Extreme Environments. Soft corals resemble the structure of asparagus as their skeleton is composed of tiny rods; whereas, stony corals are also called reef builders as they grow rapidly forming the framework of reefs. The growth in stony corals vary significantly as stag horn corals grow about 10 cm annually while others only grow 0.5 cm (Anlauf, D’Croz& O’Dea, 2011).

The coral reefs are present in various zones, having varying biological communities and antibiotic characteristics. The distribution and zonation of coral reefs depend on their exposure to air, sedimentation, salinity, light, depth and temperature.

It can also be stated that light is a necessity for growth and expansion of coral reefs as it supports the process of photosynthesis by Zooxanthelle. Lastly the most suitable range of temperature for occurrence of coral reefs is 18-25 degree centigrade,Extreme Environments so extremely high and low temperatures limit the occurrence and growth of coral reefs.

In terms of diversity, corals found today represent one of the most multifaceted and diverse ecosystems as they have survived extreme environmental changes throughout their existence since 500 million years ago.

The largest reef is the Great Barrier which is spread over an area of 145 km by 2,000 km. To add on, in the Cretaceous period 70% corals became extinct, however almost 185 new genera of corals such as Acropora or Monastrea have evolved thereafter which has increased diversity on coral reefs (Angelini Et al., 2011).

Furthermore I believe that in terms of symbiotic relationships, coral reefs have strong symbiotic associations with animals through which they work together and support each other. The major threats to existence of coral reef are destruction through biological or physical factors such as, storm damage, beaching events, predication and human disturbances.

Hurricanes and tropical storms break corals and throw boulders in reef bottoms. An increase in freshwater due to heavy rainfall can also damage coral reefs.

There is an increase in bleaching events due to global warming as the Zooxanthelle leave coral heads. This leaves only the sides of coral reefs alive. Moreover certain predators like echinoderms and molluscs destroy corals and certain fishes like box fish bite corals.

Certain human activities that result in destruction of coral reefs are mining and dredging of coral, polluting sea water and increased oceanic tourism (Kumar, Geetha&Sornaraj, 2013).

It can be concluded that out of the aforementioned threats, the ones posed by human beings to include: global warming; mining; dredging; pollution of sea water and oceanic tourism, pose a far greater threat to the coral reefs than the natural ones.

This is primarily because the impact of natural calamities is almost always counterbalanced by the formation of new reefs, while the adverse effects of the human activities cannot be reversed.

1.3 Adaptive Strategies within Coral Reefs and Effects of Climate Change & Human Intervention on Coral reef Conservation

            There are various adaptive strategies within coral reefs through which they survive numerous environmental conditions. The ecosystem of a coral reef might alter based on changing environmental conditions.

First of all primary production in coral reefs is influenced by nutrient availability and light intensity. In my view, light intensity is itself affected by turbidity and water depth. A wide range of research portrays the idea that coral reefs adapt to changing light levels in the form of photo adaptation…….