MARVELS OF THE SEA.

Putaruru Press, Volume VII, Issue 294, 27 June 1929, Page 8

MARVELS OF THE SEA.

TROPICAL MARINE LIFE. Of recent works dealing with the science of the sea, none is more worthy to be recommended to the interested tyro than “ The Science of the Sea: An Elementary Handbook of Practical Oceanography ” (says a writer in the Melbourne Argus). The book is the outcome, in the first p'aee of the work of the ship Challenger, which made large contributions by its long survey 'of the depths of the sea to the science of oceanography. The part of the book devoted to the natural history of the sea is, as one would expect, the larger portion. The life of a tropical shore is described by Stanley Gardiner, an authority on coral reefs, who introduces us to the many wonderful shells cast upon the beach, from tiny foraminifera to g assy sea-butterfiies, pens of cuttlefish, and the float organ of the Argonaut or Paper Nautilus, of which we have seasons 1 invasions from the tropics even on to Victorian shores. The plants, corals and shells of the seaweed zone of the tropics form a close association of their own, some of them i living together in the most amicable way, deriving common benefit. Mr Gardiner points out that the vivid green of certain corals, as well as their purple tips, is often due to a commercial seaweed or aga living within the tiny pores. Eminently suited to their conditions of living are the smaller fishes which are described as darting in and out among the coral growth. There are about twenty dif ferent kinds, and they are flattened sideways so as to more easily pene- ' trate the spaces between the reef. Viewed from above, these little fishes look very conspicuous with their vivid "stripes, splashes, and iridescence. The importance of the study of the food . of marine animals is emphasised as being of the utmost economic import ar,re. An account of the way in which a reef is broken down into fine mud and sand makes an interesting story. The process is effected by I boring worms and molluscs in the first t place, and is carried on by the crush- | ing teeth of predatory fishes and the I rasping jaws of sea urchines. Finally, the mud itself is passed through the alimentary canal of sand-feeding organisms such as sea-cucumbers and bristle worms.

The second section al this chapter by Stanley Gardiner deals with the formation of coral reefs and islands. The importance -of the superficial or living aspect of the reef formation would weigh against the geological or Darwinian theory of the making of coral islands by the building of such structures on an ancient sinking foun-; dation. This mode has beep proved in numbers of instances, however, where the (foundation of the coral island is known to be ef considerable thickness, and where, as in the Funafuti boring, shallow water foraminifera were found at the considerable depth of 1114 feet. Some coral islands, such as those especially studied by Semper in the East Indies, have a thin skin of coral growth, but against these stand the wonderful ring atolls that rise from a great depth out of the ocean floor. Curious problems concerning the formation of lagoons within coral islands no doubt sti.l require investigation, and Mr Gardiner points out the need for precise information upon what is building the reef to seaward. The solution of the problem, he says, may be furthered by serial shallow borings taken across atolls and barrier reefs, together with observations made upon the topography and conditions of the lagoon flats. In some cases the association of volcanicity with coral atolls lends colour to the earlier theory of corals building cn the rim of an extinct volcano.

The detailed account of the forms of life in the sea—its plants and animals—is probably the best and most modern of its kind, giving as it does the methods of collecting the various groups and explaining the conditions under which they live. Even the evergreen subject of the sea serpent is here discussed, though without finality, for such phnomena have been variously ascribed to a school of dolphins, a large marine eel or snake, a long arm of a cuttle-fish, or even a long-bodied sperm whale. In the last chapter is a useful collection of hints upon labelling, note-taking, and ways of writing up a log-book, with abbreviations of data of sounding material, wind, and weather.