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Long, long ago the landmass that we now call Australia was located near Earth's southern pole. Through tectonic activity the continent began moving to the north at a pace of just inches per year thoug...
Click through to see the images.
Long, long ago the landmass that we now call Australia was located near Earth's southern pole. Through tectonic activity the continent began moving to the north at a pace of just inches per year though, and after many millions of years drifted to its current location. As this occurred, the northern parts of the continent gradually moved into the tropics, and coral reefs began to form along parts of its coastline and continental shelf around 25 million years ago.1
Since that time, changes in climate and sea level caused coral growth to wax and wane significantly, but around 600,000 years ago a large-scale reef structure began its development and eventually became today's Great Barrier Reef.1 The early version of the GBR also came and went to a large degree, but the current living structure has been growing for about 20,000 years now.2 So, there have been corals and reefs growing, dying back, and re-growing there for a very, very long time.
Strung along Australia's Queensland coast, the reef is located in the Coral Sea, and is the largest structure on Earth made by living things. So large in fact, that it can seen from space, and is commonly considered to be one of the seven natural wonders of the world. It starts at a bit more than half-way up from the bottom of the east coast and extends up along the continent's horn to Papua New Guinea. That's roughly 1,500 miles, meaning if you laid it along the east coast of the U.S. it would reach from Miami to Boston. It also covers about 130,000 square miles of the seafloor.2 It's not one humongous and continuous coral reef though, as it's actually comprised of about 900 islands and almost 3,000 individual reefs.2
Copyright Dive the World (http://www.dive-the-world.com/). Used with permission.
Around and amongst these islands and reefs live a great number of organisms, including approximately 1,500 species of bony fish and 130 species of cartilaginous fish, plus 30 species of marine mammal, 14 species of sea snake, 6 species of sea turtle, and an occasional salt water crocodile that makes a long swim out from the mainland.2 There are also about 600 species of stony and soft coral, 40 species of anemones, 100 species of jellyfish, 330 species of sea squirts, 400 species of bryozoans, 630 species of echinoderms, 1,300 species of crustaceans, 1,500 species of sponge, and as many as 5,000 species of mollusc.2 Plus, about 500 species of marine algae to finish off the list.2 Thus, the Great Barrier Reef is certainly a great place to do some diving.
This is just an example of the coral cover in some areas.
A tiny and unknown (to me) fish on a branch of Tubastraea micrantha.
This was an odd scene for sure. A crinoid climbing up the body of a standing sea cucumber, Bohadschia graeffei.
A pixy hawkfish, Cirrhitichthys oxycephalus, hanging out next to a sun coral, Tubastraea sp., and a sponge, Nara nematifera.
It took a few years, but I finally accrued enough frequent flyer miles to get a ticket to the land down under, and I made the long trip to the far southwest over my winter break from school last December. I spent several days in Sydney to get a feel for the big city life there, and also spent a week in the ancient and magnificent rainforests around Cairns in the north, but the primary reason for going was obviously to dive on the reef.
Unlike many other places where I've been diving around the world, you can't just walk in and swim to any part of the reef. Nor can you hop in a small boat for a brief ride. Instead, you need to get on a larger boat and take quite a trip out for the good stuff. So, I pulled out my credit card and booked a week-long excursion on the 122' Spirit of Freedom out of Cairns, which was one of the best decisions I've ever made.
The Spirit of Freedom, and Christmas Eve on board with Trip Director Nick Leigh.
After getting out to sea, the diving started and didn't stop for the week. There were 28 div