We tried not to get our hopes up too much about seeing the Great Barrier Reef. A couple at the hostel said the portion they saw was pretty trashed out – people had stepped on and smashed some of the corals, other corals were bleached, and overall the reef wasn’t as colorful as they had hoped. However, we couldn’t help getting at least a little excited – we knew that since light gets progressively filtered out by water the deeper you dive, corals at deeper depths look less colorful, but not necessarily because they are damaged. The Cairns Harbor is surrounded by mountains cloaked in rainforest vegetation which grades into mangroves and in deeper waters corals ring the coastline. Here the rainforest truly does meet the reef. The shades of green and blue are largely unbroken – there are no major roads and just a few houses and fishing shacks. In places the mountains give way to natural harbors complete with quiet swimming beaches.
While snorkelling we discovered a huge brain coral, easily more than a meter in diameter, and small portions were covered in what looked like a slime mould. Elkhorn coral lit up the water with vibrant blues and purples. It grows quickly relative to other coral species and occasionally these tall spikes are broken off by wave action. Soft corals appeared to be bunched up, fluffy, gold carpet reminiscent of the 1970’s. Their tentacles waved gently in the current, creating a wave propagating across the coral from one side to the other.
Coral reefs are underwater forests. Competition for space is fierce because the symbiotic algae that provide the coral with food require sunlight. The table top coral we saw was true to its name - it had a large flat section growing out of a ‘pedestal.’ It was doing a good job of shading out other coral species. Where the table top coral came into direct contact, the other species sported a scar-tissue band, evidence that the chemicals the table top coral produced were effective at opening up new, valuable space.
At Michelmas Kay the majority of the coral is located on the leeward side where the island offers the most protection from prevailing currents and waves. The reef here occurs in very shallow water and several times I got so close that I felt as if I was going to run into it. We saw several sting rays flying across the sandy ocean floor, but even more spectacular were the humongous giant clams at least one to two meters long. The shells were filled with dark purple flesh and two siphons were present – one pumped water in and the other pumped water out.
To some extent one can appreciate the Great Barrier Reef through facts and figures. We learned that one square inch of coral has, on average, 3 million zooxanthellae (the symbiotic algae living in coral) which are smaller than phytoplankton. A bleached coral, which has expelled some zooxanthellae due to rising temperatures, only has about 1 million algae per square inch. Reefs close to the Cairns shoreline are only 10,000-8,000 years old and were formed when rising sea levels inundated the area after the last ice age. Experiencing the reef in-person holds something much deeper however. Swimming over the same corals is delightful because there is always something new to discover – different fish swaying in the ocean’s current, giant clams opening and closing their shells, and coral polyps filtering the water for food.
Other islands such as Fitzroy are not sandy at all but instead are rocky mountain peaks formerly connected to the mainland when the sea level was much lower. Fitzroy Island is littered with huge granite boulders which have broken off the mountain and are lodged against trees or each other. Bird’s nest ferns grow on top of the boulders where soil and leaf litter has accumulated in crevices. The rainforest vegetation allowed us to look back in time and catch glimpses of cycads, ferns, and early conifers which first evolved in Jurassic times when the earth’s continents were connected in one large mass known as “Gondwana.”
Gradually the rainforest on Fitzroy gave way to open forest, or ‘bush’, as Australians call it. Wild bush turkeys were rustling in the leaf litter scratching the soil for food and accumulating large piles of leaves to lay their eggs in a few months time. Numerous lookout points provided views of the shimmering blue ocean, neighboring mountain peaks, and boulders which had tumbled to the beach and were supporting coral reefs. Hazy clouds made it appear as if the sea and sky were one.
The beach on Fitzroy Island is blanketed by several meter thick deposits of broken elkhorn coral. How did these coral pieces break off since it is impossible to break them by hand, we wondered? Then we hit one piece of coral against another – and it broke. During a storm with fast currents and large waves a piece of coral that is already broken off must get lifted up and knock into other corals, causing them to break off in turn. Eventually the coral on the beach is turned into sand by wave action.
Fish at the Fitzroy Island reef were a fusion of color. A school of electric green and blue parrot fish gnawed at algae growing on the coral. In nature’s great recycling process one parrot fish processes several tons of dead coral each year turning huge structures into tiny grains of sand. We were so close to the parrot fish that we could hear the rasping sound. Soft corals waved their tentacles in the current and a more docile orange and white clown fish was hiding in an anemone nearby. We both loved the Great Barrier Reef and Fitzroy Island – it truly was a ‘great’ natural paradise where the rainforest and reef become one.
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