Coral Reefs

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What’s the fuss over corals?

Corals are pretty to look at and are definitely pleasing to the eyes!  Besides being a necessary prop in the aquarium and enhancing its appearance, what has it got to do with us anyway? 

Corals – What are they?

Corals are invertebrate animals (without a backbone) that are related to sea anemones.  They share the same characteristics - a simple stomach with a single mouth opening surrounded by stinging tentacles.  Each individual coral animal is called a polyp.  Polyps group together to form a colony by replicating copies of its original self through a process called budding.  When coral polyps die, they leave behind a hard, stony, branching structure made of calcium carbonate.

Corals are generally classified as either "hard coral" or "soft coral". Soft corals live in colonies that resemble brightly coloured plants or trees and don't have hard calcareous skeleton, instead they grow wood-like cores for support and fleshy rinds for protection.  Hard corals are known as 'reef building' corals.

What are coral reefs?

Reefs are usually made up of many colonies and are much bigger. These structures are formed when each individual polyp secretes calcium carbonate. The largest coral reef is the Great Barrier Reef, which spans 2,600 km off the east coast of Australia. It is so large that it can be seen from space. 

Massive corals tend to grow slowly, increasing in size from 0.5 - 2 cm per year. However, under favorable conditions (lots of light, consistent temperature, moderate wave action), some species can grow as much as 4.5 cm per year.

Threats

1. Water temperatures and ocean acidification linked to rising carbon dioxide levels.
• High water temperatures – condition called coral bleaching causes corals to lose the microscopic algae that produce the food corals need.
• Ocean acidification - more acidic seawater makes it difficult for corals to build their calcium carbonate skeletons.

2. Overfishing and overharvesting of corals disrupt reef ecosystems.

3. Invasive species -  greatly impact coral reef ecosystems through consumption of, and competition with, native coral reef animals.

4. Runoff from lawns, sewage, cities, and farms feeds algae that can overwhelm reefs. Deforestation hastens soil erosion, which clouds water—smothering corals.

How do corals contribute to the environment?

1. Coral reefs are sensitive indicators of water quality and the ecological integrity of the ecosystem.
• They tolerate relatively narrow ranges of temperature, salinity, water clarity, and other chemical and water quality characteristics.

2. They are important fishery and nursery areas, and more recently have proved to be very important economically as tourist attractions.
3. Reefs provide protection from erosion to coastlines and sand for beaches.

http://www.icriforum.org/about-coral-reefs/what-are-corals
http://ocean.si.edu/corals-and-coral-reefs

Get to know the corals

 Assoc. Prof. Dr. Hii Yii Siang in action

  Assoc. Prof. Liew Hock Chark in action

  Look,look...that is the corals!

Meet the corals

This article is written in conjunction with Petrosains Public Engagement Session on 15-17 December 2012 with scientists from Univeristi Malaysia Terengganu, Assoc. Prof. Dr. Hii Yii Siang and Assoc. Prof. Liew Hock Chark.