THE GREAT BARRIER REEF
Within the tropical parts of the great South Sea are submarine gardens that in the beauty of their floral forms and their richness of coloring rival the most elaborate flowerbeds made by man; in color and variety they are fairy regions of exquisite living animal flowers. One of the greatest and most attractive of these sea gardens lies off the coast of Australia.
Of all the wonderful animal structures in the world the Great Barrier Reef of Australia is the most remarkable. It consists of a chain of coral islands and reefs parallel to the east coast of Queensland. This great reef is about twelve hundred miles long, and the distance from the mainland to its outer border is from ten to more than one hundred miles. It is far enough off the coast to leave a wide channel between the reef and the shore.
Since it is well charted this channel is the route taken by many vessels. It is admirably furnished with lighthouses and light-ships, and is protected from the huge rolling billows of the ocean by the reef itself. There are several breaks in the reef through which vessels can pass out into the open ocean.
This mighty barrier, the work of coral polyps, is of special interest not only on account of the curious shapes and varied kinds of sea life it presents, but because of the commercial value of its products. The bêche-de-mer, pearl, oyster, and sponge fisheries yield an annual revenue of upward of half a million dollars, and when all of the resources of the reef are properly exploited the returns will be more than doubled.
The habitat of the reef-building coral is in clear tropical waters. The polyps thrive best near the surface; they cannot live at a depth exceeding one hundred and twenty-five feet. The reef-building coral must not be confounded with the precious, or red, coral, which flourishes in a muddy sea-bottom and is found chiefly in the Mediterranean Sea.
When alive and in the water, coral polyps present a variety of beautiful forms and colors. Living polyps are composed of limestone skeletons covering and permeating a soft gelatinous substance which corresponds to the flesh of animals. When the polyps are removed from the water this soon decomposes and disappears; in certain species a part of it flows off as a thick liquid.
Fish fantastically striped and of brilliantly variegated colors are seen swimming among the coral. In tropical waters many of them have fascinating colors and patterns. By simulating the colors of the coral polyps they escape the species that prey upon them.
The different kinds of coral are generally designated by common names according to the different objects which they resemble. Thus, by similarity of form we have brain coral, organ-pipe coral, mushroom coral, staghorn coral, etc.
Some of the islands and reefs are the homes of sea fowl and at the nesting season are literally covered with their eggs. These fishers of the sea have marvellously well-developed faculties for location, since each bird goes directly to her nest when returning to the islands. As night approaches, when all the birds seek the land, their wild cries are deafening.