Australia's Top Tourism Treasures - The Great Barrier Reef
The polyps grow by dividing and multiplying, a process known as budding, and feed on nutrients produced by algae that live within the coral. As the polyps develop, they precipitate calcium carbonate from the seawater to form a hard limestone skeleton. It is this chalky white structure that forms the basis of the reef on which the colorful living polyps continue to grow.
If any one event epitomizes the vibrancy of life on the Great Barrier Reef, it is the mass spawning of corals, which takes place each year between October and December, over several nights just after the full moon. This is a memorable sight, with the corals ejecting huge explosions of pink and orange eggs and sperm into the dark water. Fertilization then occurs in the open sea, perhaps hundreds of miles from where the eggs and sperm originated, forming larvae that then lodge in the coral and begin to grow.
To the first-time visitor, the scale of the Great Barrier Reef is daunting. For practical purposes, it helps to think of it as being made up of three distinct sections, north, central, and south. The suitability of each as a base for exploring the reef depends on both your travel plans and your interests.
Extending from the virtually uninhabited tip of Cape York to just south of Cairns, the northern section includes some of the most remote and pristine parts of the reef but also some of its most accessible dive sites. The region's coastal towns of Cairns and Port Douglas, with their abundance of accommodations, boat operators, and dive schools, are probably the most convenient jumping-off points on the entire mainland.
Just south of Cairns, the continental shelf widens and the reef is less dense and more distant from the mainland. Nearer the shore, however, lies an abundance of fascinating continental islands, including Hinchinbrook Island and the idyllic Whitsunday Group, some of which have fringing reefs.
The principal mainland center here is Townsville. Less tourist-oriented than Cairns, this very low-key city lies a good two and a half hours from the reef by boat. But it does have a 650,000-gallon Great Barrier Aquarium, which features many of the corals and marine creatures found at sea and has even developed its own reef ecosystems.
From Townsville, it's a short hop to beautiful Magnetic Island, with its boulder-strewn shores and succession of spectacular bays. Nearly two-thirds of the island is national park and includes 15 miles of trails. Divers can also explore several shallow fringing reefs, including those off Alma Bay on the eastern side of the island, where they'll find gardens of large brain, staghorn, and plate corals, and may encounter six-banded angelfish and ornately patterned boxfish. From some of the world's largest mammals to the most minuscule and delicate of sea anemones, the range of life on display on the Great Barrier Reef is truly astounding. Whether you choose to explore its gleaming coral cays on foot or discover its myriad underwater treasures by immersing yourself in the warm waters of the Coral Sea, you're sure to agree that for once the phrase "wonder of the world" is entirely justified.