The coral fairyland. 



At the bottom of the Pacific Ocean extends an immense deep-sea landscape at depths of 

 1,600 to 3,200 fathoms or more, a sea floor stretching without interruption from north to south 

 of this ocean. But in the tropical zone, between latitudes 30° N. and 25° S., insular shelves 

 bear archipelagos and island chains. Sometimes a volcanic peak towers above high-topped 

 palm-trees; sometimes the island is quite flat, only the low barriers of the mangroves showing 

 on the horizon; sometimes there is no island, but a great circle of foam denotes a belt of reefs 

 enclosing a sheet of calm water reflecting the deep-blue, equatorial sky. This oceanic region 

 with emergent islets and atolls is the Coral Sea. Continental subsidence marks its far distant 

 past, while volcanic archipelagos have risen elsewhere ; some still persist, others have disappeared, 

 for the period of changes in the earth's crust is by no means past. 



Volcanic activity and coral building are the essential bases of island formations in the Pacific 

 and they are closely linked. Due to volcanic changes an excess of carbon dioxide leads to a 

 supersaturation of calcium carbonate in the sea water. It is this massive, chalky deposit that 

 is transformed by all the organisms living in the Coral Sea. The appearance and shape of the 

 polyp structures varies according to the lay-out of the subsided lands. On the sites of sub- 

 merged islets atoll-rings arise. The borders of ancient continental shelves bear fringing reefs 

 and barrier reefs, the Great Barrier Reef of Australia being among the latter. This mighty 

 rampart of more than 1,200 miles in length rises ofT the Queensland coast from a depth of about 

 80 fathoms. It is intersected with channels and there are islets and sandy banks. The madre- 

 poric coral masses are ceaselessly subject to marine erosion and the sand formed as they crumble 

 cements together the trunks, stems and branches of the coral colonies or falls slowly to the 

 bottom of the lagoons. The wind carries plant seeds to these fortified reefs, and currents 

 deposit seeds and coconuts. Breadfruit trees and mangroves fasten their roots into cracks 

 and the mangrove swamp gradually yields a soil allowing the growth of other plants, such as 

 palms and banyans. Eventually these push the swamp back from the fertile soil that it has 

 created. 



There are innumerable varieties of madrepore corals. Some Aslroides species have slender 

 branches like stags' horns; others have cups with crenelated edges and look like gear-wheels, 

 while strong, wavy crests separate the lodgements of brain-corals. Fungias spread out like 

 the upturned umbrellas of mushrooms with their radiating plates. Countless coloured or immac- 

 ulate polyps open out, graceful flowers of a garden that could not even be described by the 

 most poetic of the Arab story-tellers. Remarkable creatures with brilliant, blending colours 

 are fastened on the corals. There are alcyonarians with purple or orange branches, pink or 

 yellow gorgonians, tube-dwelling worms with extending, many-coloured plumes, and sponges 

 of all shades. Among these tangled thickets open the massive wavy-edged valves of giant 

 clams (Tridacna) with their scarlet mantle lining. Sea-urchins erect their sharp-pointed 

 spines, which radiate like the quills of a porcupine. Conch-shelled or helmet-shelled molluscs 

 drag their massive shells with their orange enamellings or mother of pearl lustre. Star-fishes 

 stretch their red or green arms and fleshy nudibranch molluscs crawl around, looking like 

 enormous marbled or spotted slugs. 



A strenuous life prevails throughout the coral reefs. Each crevice is a shelter giving con- 

 cealment and some security to crowds of timid creatures, when it is not the haunt of some formid- 

 able animal. Lying motionless and watchful in holes are great moray eels (Echidna and 

 Lycodontis) reaching a length of more than 6 feet. Their long snake-like bodies with their 

 patterns of spots and mottlings, together with dark-brown or light-yellow shades, blend most 

 strikingly with the colours of the corals. Unseen, they await the passing of an unwary fish. 

 This suddenly stops, held by the gaze of two small cruel eyes that are fixed on it. Although 

 the triangular head is slowly getting nearer, it is unable to get away and so becomes the easy 

 prey of the fierce moray eel. 



While they are very voracious fishes, groupers are less dangerous predators. Owing to 

 their perfect camouflage they lie hidden among the craggy outlines of rocks. In spite of their 

 heavy bodies they can dart out with incredible agility to savagely snap u|) some appetising prey. 



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