GREAT BARRIER REEF.

Otago Daily Times, Issue 19531, 14 July 1925, Page 4

GREAT BARRIER REEF.

EXPLANATORY PLANS. CAPTAIN COOK’S ADVENTURE. ON A OORAL-BOUND COAST. It waa an Anglo-Australian committee that decided to investigate the ancestry of the South Pacific cora island, Funafuti, nearly 30 years ago; and Australians and English alike are now in "the forefront of scientific investigation of, and are becoming quite enthusiastic about, the largest coral reef in the world —the Great Barrier Reef. This lies, so to speak,- at the doorstep of the Australian continent, and far from being a calamity to Queensland, as one eminent geographer has put it, it will yet prove to be one of hear richest resources. In Juno, 1770, Captain Oook was charting the octal-bound coast of north-eastern Australia, and unfortunately not recognising the coral islands as such, struck, on June 11, the Endeavour - Reef, between 1 ort Douglas and Oook town. The hole mace in the ship was temporarily covered with a sail to enable her to reach land (writes F. Chapman, A.L.S., in the Melbourne Argue), and she waa aftferwards laid o« the beach and repaired, on the spot where Cook town now stands. Ascending Griissv Hill, Captain Cook, to his dismay, saw the network of reefs extending in all directions. He eventually sailed cautiously through the reefs until he reached the open sea, but was glad to get back within the reef through Providential Channel, and thence he sailed into Torres Strait. Cook s subsequent landing on Possession Island marked the formal annexation of the eastern coast of Australia. Since Cook’s time, many disasters to shipping have occurred, but charting has been so thoroughly carried out that the danger to vessels is now greatly diminished. By recent Admiralty investigation, however, it was found that charting must be carried on continuously, for the coral in some parts attains a rapid growth, and a channel which is situated on a stationary or slightly rising submarine platform quickly becomes filled up, as by a cement, with drifting organisms, or even blocked by the growth of the coral itself. To the Australian, the Great Barrier Reef is of the highest interest,, not only from the points of view of the navigator, the biologist, and the geologist, but of the man of oonunßrcß, Its dommorcial valu© has been inquired into of late years in Queensland, with a great deal of enthusiasm, largely due to the formation of the Great Barrier Reef Committee of Brisbane. His Excellency the Governor (Sir Matthew Nathan), who presides over the investigations of the committee, which by the way comprises representatives from most of the scientific institutions in the commonwealth, showed great foresigh* in haying these investigations put on a commercial as well as upon a scientific footing. r l hat the scientific importance of the work will not be neglected is assured, since the secretary of the committee is Professor H. O. Richards, of the Geological Department ol the Brisbane University, whoso name was misprinted in the paper noticed below as Professor C. H, Ricards. A VISITOR’S 'IMPRESSIONS. In view of what is now being done, it is especially interesting to notice an informative account of a visit made to this remarkable reef by Sir Gerald Lenox Conyngham, F.R.S., on overseas member of the Pan-Pacific Congress; in 1923. His description, together with a general biological discussion of, coral reefs by Mr F. A Potts, was read bdfore the Royal Geographical Society in February, and is published in the April number of the Geographical Journal, with the title ‘The Great Barrier Reef.” In the forepart of his paper Sir Gerald gives, in picturesque language, a description of the coral reef scenery and the characters of the component parts of the reef platform. He cites the generally accepted explanation of •the occurrence of the "negro-heads” as being due to jetsam of coral rock thrown up by the waves and subsequently eroded around their base, as apposed to the opinion of Akteandod Agassiz, who visited the Great Barrier Reef in 1896, ttnd held that these, eroded blocks were direct proof of an elevation of the coast. Sir Gerald praises the effort® of the late E. J. Banfield, who made his home on Dunk Island, and who there wrote his interesting books, ‘‘Confessions of a Beachcomber” and “My Tropic Isle.” , In regard, to a visit to Dunk Island, he says (.'“ty.is a veiy delightful spot, and give® porhapn a • foretaste of what many of these islands may in the course of time become, when occupied, cultivated, and adapted to human needs.’’ In the second section of the first paper Sir Gerald restates the main problems connected with the formation of coral reefs, and emphasise® the fact' that the platform on winch the outer reefs are built must have * been caused by subsidence of the coast. He also seems satisfied with the explanation of that phenomenon given by Hedley and Griffith Taylor, as caused- by “tectonic rookigg,” but suggests that light may be thrown upon it by correlating the evidence with the trend-lines seen in the parallel arrangement of the groups of islands in the Pacific. This is an already accepted correlation. Some excellent suggestions are made as to future lines of research on the Great Barrier Reef. One of these is “the causes which lead to coral growth in some localities and to absence of growth in others.’’ Sir Gerald points out that the general flatness of the reef renders it particularly suitable for aeroplane photography, and further remarks that, “if in conjunction with that work (of ’reef survey) an aeroplane survey of some part could be undertaken, I believe that the way would be opened to a great increase of our knowledge of the laws of coral formation.” This departure in surveying has, I believe, already met with success. BIOLOGY OF THE REEF. In the latter part of this article Mr F. A. Pott® contributes a very readable account of “The Life of the Reef.’’ This is illustrated with' some beautiful photographs of the Barrier Reef and other scenery. An interesting observation made by Mr Potts in the Samoan coral reefs is that, where living coral is often unable to stand the full force of the heavy breakers and ceases to grow, it is covered with a thin living cruet of a calcareous alga or Lithothamnion. The dead corals themselves ore usually encrusted with a smooth layer of this calcareous weed, which prevents the erosion of the coral and also protects it from the depredations of boring organisms. In remarking on the variation of growth form in corals induced by their surroundings, the interesting fact was mentioned of a small crab, Hapalcareinus, .which settles down between two finger-like branches of a coral. Pocillopora, controlling the growth of the coral by the current of water she sends out from her gillchambers. When the crab dies the chamber is stalled up by the coral, and a galllike structure is formed. Of particular Interest were the remarks on the paper by the hydrographer to the Admiralty, Captain Douglas, who spoke of the immediate preparations that were being made in order to survey the Great Barrier Reef in conjunction with the Royal Australian Navy. Professor Stanley Gardiner, a recognised authority on coral reefs, referred to the proposed boring into the reef, and expressed the opinion that it should be put down about halfway be-, tween the edge of the reef and the present coast in order to. test the existence of a submerged sandy shore. It is refreshing to hear of a biologist attaching great weight to the fact, that the accumulated sediments of coral and other material must eventually cause subsidence, since few have admitted it in the past. Professor Gardiner expressed the view “that the reefs of the Pacific are very recent indeed. Personally. I mean about 20,000 to 00,000 years.” This would more or loss accord with the time taken to form the total vertical thickness of the 1100 ft penetrated by the bore at Funafuti. At Funafuti, however, the theory ol the melting icecap or glacial control of Professor Daly would only apply in a very limited sense, as Professor E. \V. Skeats has so convincingly shown in his paper on “The Coral Reef Problem” in the American Journal of Science, 1918, for the boring mentioned proved such extremes of actual depth that instead of a continuous raising of the ocean level, postulated by Daly’s theory, there must have been several distinct oscillations. We do not know whether or not to take the concluding remarks of Professor Gardiner seriously, for lie says; “I venture to think that it is the greatest pity in the world that there is a Great Barrier Reef. Its existence is really a tragedy so far as the people of Queensland are concerned. It i-J a great nuisance to navigation. It Is also a curse, because it destroys 70,000 to 80,000 square miles of most admirable trawling ground.” He adds, however: “Pearlshell is becoming very scarce, and T trust that (hose responsible for the investigation of Hie Barrier Reef will consider the possibilities of starting thlat industry in the region, the way to which Inis been paved by researches in the Red Sea and elsewhere,”