A Complete Ecosystem in the Pacific Ocean
I took a very long plane trip to get to the Great Barrier Reef from the U.S. I took off from Newark Airport on Sunday afternoon, and after many hours in the air, and several flights, I arrived in Cairns, northeastern Australia on Tuesday Afternoon. Yes, how bizarre; our trip (from start to finish) took about 30 hours but, in addition, we also crossed the International Date Line so we lost a day. So the combination of long flights and crossing the International Date Line accounts for arriving 2 days after we left! How about this for a "fun fact"-we were delayed several hours in Los Angeles because Qantas was having difficulty with the gasoline pump that fuels the Boeing 747 that we were going to take from L.A. non-stop to Sydney. This aircraft carries 140 tons of fuel to make that 15-hour flight. One of the pumps that loads the fuel on to the plane was not functioning up to capacity so the fuel could only be added at about 1 ton per minute. I guess the airline thinks that's slow, although that sounds pretty fast to me! Isn't it mind-boggling to think that a metal object could stay in the air with several hundred passengers, thousands of pounds of luggage and 140 tons of fuel! Thank the laws of physics (Bernoulli's Principle) for such an amazing feat that got me across the Pacific Ocean to Australia.
So, after the flight and several days of studying beautiful tropical forests in northern Queensland, Australia, it was time to take a boat trip out to the Great Barrier Reef. The Great Barrier Reef extends for over 1400 miles along the northeastern coast of Australia. It is actually 3,000 individual reefs (Matthews, 2000). No place on land, not even the beautiful tropical forests that we visited has a greater diversity of life than the Great Barrier Reef. The reef is home to:
- 400 types of coral animals
- 2,000 species of fish
- 4,000 species of mollusks (Bennett, 2000)
Many of these reef organisms are beautifully colored and live in harmony with each other. For example, orange anemone fish (clown fish) have mutualistic living relationships with sea anemones. The fish lures in food for the anemone (and also for itself) and is immune to the anemone's stinging cells. The anemone provides protection for the fish who keeps the anemone well-supplied with food. If you watched the Disney animated movie, Finding Nemo, Nemo and his father were clown fish. His father reminded Nemo to brush against the anemone daily to build up his immunity to the stinging cells. Their friends are butterflyfish, pufferfish, and other typical reef fish. The movie will show you some good examples of the beautiful reef fish we saw.
Another great example of living in harmony on the reef are wrasse "cleaning stations". Larger fish come to the cleaning station to have pieces of food cleaned out from between their teeth and parasites plucked from their skin. Normally, the larger fish would be considered predators for these smaller 4 cm -7 cm long wrasses, but the larger fish open their jaws and wait patiently while several wrasses dart around the inside of the larger fish's mouth pulling out pieces of their last meal from between their teeth and around their gums. The larger fish come willingly to the cleaning station to get their teeth cleaned and the little wrasses get an easy source of food.
The Crown of Thorns sea star is again threatening the health of the Great Barrier Reef. These echinoderms devour coral at a much faster rate than the coral can re-build itself. And if these sea stars get broken into several pieces, each of the pieces can grow a whole new sea star. This is called regeneration and is a very valuable adaptation to the Crown of Thorns, but this makes it more difficult for humans to try to control the Crown of Thorns population.
In order to protect the beautiful coral formations, some of which are almost 2 meters tall, boats are not allowed to anchor on the reef. Anchors do a lot of damage when they are dragged by waves and tides over the magnificent coral formations.
We snorkeled around Fitzroy Island and saw many beautiful tropical fish swimming amongst the corals. I've done extensive snorkeling off the Florida Keys and in the Caribbean, but this is the first time I saw a bright blue coral. The hard structure of the coral is the "home" that the coral animals build and live in. The animals build their homes on top of other dead coral.
The animals remain in their hard, protective home, but extend their tentacles (often at night) to catch food that drifts by. They use their stinging cells (cnidocytes and nematocysts) to stun or kill their food and they use their tentacles to bring the food into their mouths. I could see how much coral is broken off by natural wave action walking along the beach on Fitzroy Island. The beach is not sand, it is rather large size coral pieces. You definitely need water shoes to walk on this beach! We were not allowed to take any of this dead coral because the Great Barrier Reef is an International Park and all the plants and animals are protected.
I was amazed that even though I was snorkeling in a different ocean from Florida and the Caribbean islands, many of the fish were similar to the Atlantic Ocean tropical fish; sargeant majors, yellowtail snappers, wrasses, butterfly fish, angelfish, clownfish, and many other brightly colored fish.
Many of the reef fish, although brightly colored have markings that are meant to confuse their predators. For example, butterfly fish often have a dark colored eyespot near their tails. If a predator tries to catch a butterfly fish and mistakes the tail for the head, the butterfly fish will be able to escape since it will swim away from the predator in the opposite direction than the predator expected.
The Great Barrier Reef is such a diverse ecosystem and it is crucial that we do all that we can to preserve and protect it.
Bennett, Jane. Watching Wildlife: Australia, First Edition. Lonely Planet. Sept. 2000.
Leigh, Egbert. A Magic Web. New York:Oxford University Press, 2002.
Matthews, Anne, Essential Australia. Chicago, Contemporary Publishing Group, Inc, 2000.
Pascack Valley HS
Jackie Willis, Ph.D.
Montclair State University
Upper Montclair, NJ
Special thanks to Professional Resources in Science and Mathematics (PRISM) at Montclair State University and Dr. Jackie Willis for making these ecology trips possible and for sharing her wealth of knowledge, her expertise, and her photographs with us.