Flora and Fauna

What is it that makes the Red Sea so special?

It is the existence and the effect of the coral reefs, which make the Red Sea such an attraction for both divers and snorkellers. Every area in the world can be classified by its type of environment and usually, on land, it is very obvious to see what kind of environment there is. It may be mountainous or desert, estuary or urban.

As soon as we identify the type of environment we almost know what kinds of animals and flowers we can expect to find there. By example, we all have some idea what we might expect to see on an African grassland plain. However, it may not be always quite so obvious to a casual observer that there are also very different types of marine environments around the world. An area of artic sea will support very different animals and plants compared to an area of tropical coral reefs.

The Red Sea supports very good coral reef growth. Coral reefs are massive structures made of limestone, which has been deposited by living animals. Each of these animals is called a coral polyp. The limestone is like cement, which builds up around each polyp and attaches it to its neighbour. The limestone is produced as part of the coral polyp's natural life cycle.

A coral reef will be built up over many thousands of years by millions of coral polyps "building" on top of and next to one another. Certain local conditions can speed up or slow down the speed at which the reef can "grow". These conditions include a warm and steady water temperature, bright sunlight, a gentle and consistent current, a supply of certain nutriments in the seawater and a lack of pollution and silt in the water. These conditions have been reasonably consistent in the Red Sea for many centuries hence its wealth of coral reefs.

The reefs, formed by the bonding of the many coral polyps, provide a very attractive environment for thousands of other species. Small creatures live in holes on the reef and bacteria and algae live on the surface of the reef. These provide food for small crustaceans and fish, which, in turn, are hunted by larger fish, etc. This cycle of events, where one species supports another species and this is repeated over and over again, is called an ecosystem. It can obviously be very dangerous to interfere with an ecosystem, for instance if one of the species is "removed" the whole interdependence may be destroyed.

The ecosystem in the Red Sea is a huge complex relationship involving hundreds and hundreds of different species but the coral reef is the foundation for this fascinating environment.

It is this ecosystem, which attracts the colourful array of creatures, which populate the reef itself and the thousands of beautiful and varied fish, which are seen by divers and snorkellers whenever they venture into the Red Sea.

This is why Easy Divers staff will ask clients to take considerable care when swimming close to coral and other living creatures. Any damage or even interruption to the ecosystem may have tragic consequences for members of the reef community.

Coral Polyps

Coral polyps are small, sedentary marine animals, which are related to the sea anemone. Scientifically they are known as colonial cnidarians. As divers what we normally see are communities of coral polyps, not individual polyps. There are hundreds of different species of corals but generally they are described as either hard or soft corals.

Hard Corals

The hard corals are the larger group and are characterised by their external skeleton of limestone (calcium carbonate). They normally live in the large communities, which we call coral reefs. However a few do live in either small groups or even individually. Their size varies from a few millimetres to several centimetres in diameter.

Most of the hard corals are named after the shape of the structure they form, such as brain coral, elk horn or mushroom coral.

In many shallow-water species the polyps have unicellular plants or algae, called zooxanthellae, living inside them. These may provide the high oxygen concentration required by such corals.

These algae are able to consume the carbonic acid, which is produced as a waste product by the coral.

If it were not consumed then the acid would destroy the limestone structure of the reef. The algae are protected by the coral structure and derive their nourishment from the minerals deposited on the coral by the many other creatures living around the reef. The relationship between the coral and the algae, which is beneficial to both of them, is called a symbiotic relationship.

The algae are small plants and like most plants, need sunlight to pass through the water to allow them to photosynthesise and survive to protect their host, the coral.

It is because of the importance of these algae, that Easy Divers staff will encourage clients to exercise good fining technique and not stir up the seabed. This is to avoid redistributing sand, sediment or rubbish onto the reefs.

Soft Corals

Soft corals, which include such creatures as sea fingers and sea whips, are soft and bendable and often resemble plants or trees. These corals do not have stony skeletons, but instead grow wood-like cores for support and fleshy rinds for protection. They are referred to as ahermatypes or non-reef building corals. Soft corals are found in both tropical seas and in cool, dark regions.

Coral polyps feed in two ways. They can obtain their nourishment from the algae with which they live or they can feed by stretching out their long, stinging tentacles (called cnidae) to capture the zooplankton that are floating by in the current. The captured plankton are then put into the polyps' mouths and digested in their stomachs. The small tentacles are very delicate.

Our staff will encourage divers to exercise good buoyancy control in order to avoid touching the coral reef and possibly damaging it .

Coral Reefs

A good way to imagine a coral reef is to think of it as a bustling city or community, with the buildings made of coral, and thousands of inhabitants coming and going, carrying out their business. In this sense, a coral reef is like a metropolis under the sea.

The actual reef can be made up of more than just the coral polyps. Over the thousands of years that it takes a reef to develop, there will be an accumulation of skeletal material, damaged shells, sand, stones and other detritus, broken and piled up by wave action, and cemented together by the limestone. Importantly the reef will only grow on a firm foundation. The great amount of time, which it takes for a reef to build-up means that only certain types of corals will develop in particular conditions. Some reefs have been found to have started growing 50 million years ago. The reef, its corals and other inhabitants cannot adapt to rapid changes, such as can be caused by tourism and its associated construction.

Although corals are found, both in temperate and tropical waters, reefs are formed only in a zone extending at most from 30°N to 30°S of the equator. The reef-forming corals do not grow at depths of over 30 m or where the water temperature falls below 22°C. Around the Red Sea dead coral reefs will be found both at greater depths and even in the mountains which lie up to 20 kilometers in land. This is because of the considerable disruptions, which have occurred over the last 20 or so millennia, due to the Red Sea forming part of the fault in the earth's crust which extends right down into Africa.

The Red Sea Reefs are classified into different types.

Fringing reefs grow near the coastline. Fringing reefs are the most common type of reef that we see. Examples include Fanadir Reef and Fanous .

Patch reefs are small, isolated reefs that grow up from the sea bed in the shallow inshore water. They often occur between fringing reefs and barrier reefs. Examples would include Arok Giftun and Gotta Abu Ramada.

The other types of reef formations seen in The Red Sea have grown from the peaks of mountains. They will be surrounded by very deep water, such as the Brother Islands and Daedulus Reef . These are like atoll formations.