The Great Barrier Reef is the largest structure on Earth made by living things. About half the size of Texas, it can be seen from space. The barrier reef, in its present general form, has existed about 6,000 years. At one time it was sediment from a great mountain range and was not under water. The sea levels rose over thousands of years and covered it. A string of small sections of shallow (100 feet or less) land provided a perfect place for the reef to form.
The conditions needed to form the reef:
- a solid surface of sea floor that is not too deep (light needs to penetrate to the bottom)
- warm water
- movement of water sufficient to circulate oxygen well
- organisms that live and die, their skeletons remaining to be connected by algae producing limestone, providing a base for more organisms to grow and die……
The reef is constantly changing. Over 400 kinds of coral are found on the Great Barrier Reef. Coral are living organisms, polyps related to jelly fish. Algae provides the polyps with nutrients needed to create the limestone that gives the reef its foundation. Read this interesting page for information on Coral. Then watch this video for a glimpse into the beauty of the Reef. There are many great youtube videos to watch about the Reef and I challenge you to explore the variety available. I found several time lapse videos that showed coral attacking one another in Coral Wars.
One of the important concepts I learned while reading about the Reef is called Mutualism. (Source – the fisheriesblog) Mutualism occurs when benefit is gained from different parties for living. Examples include the sea anemone and the clown fish. In the movie “Finding Nemo” we saw Nemo, a clown fish, darting in and out of what looked like a plant, a sea anemone. The sea anemone has stinging tentacles that kill other small fish but the clown fish has a special protection from the sting. The clown fish can dart inside the anemone to get away from danger. In return the clown fish helps to keep the anemone clean. Another beneficial relationship is between the anemone and a crab. The anemone can attach itself to the back of a crab. By moving around more it has a better chance of catching food. The crab, in turn, is protected from predators that my be harmed by the stinging tentacles of the anemone. Mutualism is a concept that applies to more than living things on the coral reef. Can you think other examples of mutualism?
I think it would be wonderful to dive on the reef and explore some of the islands that make up the Great Barrier Reef but I would especially like to sleep on a pontoon on the reef at night. I can imagine us sitting on the deck watching the sunset and then seeing the star-filled sky. We would look up to find the Southern Cross in the sky.
This photo of the Southern Cross was captured by Greg Redfern.
The pontoon would gently rock with the water movement and lull us to sleep as the creatures of the sea move below us. The reef is different at night. Some of the fish sleep, finding protection in different ways as predatory fish move looking for food. The Parrot Fish secretes a mucus protection around itself so it can sleep. (See one sleeping). Other fish bury themselves or hide in the coral to rest.
In the morning I think we would dive to see the reef as the sun penetrates the surface providing algae light, the essential element needed for life. Photosynthesis is needed for the algae to live and it is the variety of different algae that give The Reef the beautiful array of colors. We would want to see the living reef up close and while snorkeling is one way to view it, I would want to scuba dive so I could spend more time under water. A person can’t just put on the scuba gear and begin diving though. There are important things to learn first. I took scuba diving in college and that was a long time ago so we would all need to take some classes so we would be safe.
There is a wonderful peace and quiet experienced while scuba diving. The sound of your own breathing is calming as you move with the use of your scuba fins. Big movements of the body aren’t necessary to move in the water and that is good as we would want to create as little disturbance as possible as we explore the reef. We have to keep up with one another of course and it would challenging to “tell each” other about what we are seeing. Not until we surface and climb out of the water would we be able to share our adventures.
There are dangers to the reef and its survival. Scientists have found evidence of prior reefs under the current one that died long ago. The current dangers are manmade and natural. Because the reef is a reliant upon a delicate balance of living creatures it is important that this balance be maintained. A loss or over abundance of one type of organism can create a damage that can be irreversible. One of the current threats is a type of Star Fish. Here is an interesting article about new findings concerning this threat and our hope to assist in reversing damage occurring due to an overabundance of the Star Fish.
Other factors effecting the reef include sediment runoff from rivers entering the sea. This sediment can prevent adequate sun penetration of the water. Temperature changes and water condition changes can also effect the balance of a reef and can begin to kill organisms, effecting the balance of the ecosystem. Bleaching is happening to part of the reef and scientists are worried that the Great Barrier Reef could become so damaged that it could be lost. See this article to better understand this phenomenon and the triggers that could be causing it.
I am sure that our trip to the Great Barrier Reef would be one we would never forget. What do think you would see and learn that you would want to share with your children some day?