A VAST POPULATION

Evening Post, Volume CVI, Issue 112, 17 November 1928, Page 20

A VAST POPULATION

TEEMING LIFE OF THE SEA. ."It is strange to'-think how limited is ono's knowledge- of the sea, which covers the groator part of this world of ours, and forms, for us islandors, a so familiar and significant portion of our environment. What does the landsman know of it?" asks Dr. R. Lloyd Praeger in the "Gornhill Magazine." Tho sea contains a vast population, beside which that- of the land sinks into insignificance; but where is the food supply for these countless hordes? Seaweeds in abundance there are, clothing the rocks between tides, and extending downwards to a certain depth; but this depth" -i 3 negligible. Seaweeds, like land plants, must have-light; and light becomes very dim under a few fathoms of'water;, in • consequence, the seaweeds that we know form the' merest- narrow fringe round the edge-of the land, whereas the ocean- is: populous with cratures from shore to .shore, and from the surface down tp miles, of depth. Tho microscope reveals' clue to this mystery. "Every drop of sea water taken at or near the surface is found ,to be crowded with very minute plants, known as diatoms. In countless., millions they swarm and propogate, from the polo to the equator, absorbing solar energy, and using it to build up the complicated chemical substances which form their bodies. Countless millions of minute animals find in these microscopic plants their food supply, breaking down in the.course of digestion tho materials of the plant-body, and utilising the energy thus set free for the purposes of their own lives. On these microscopic animal forms, in turn, larger sea beasts prey, and so on, it may be through a chain of many links, till we reach the giants of the ocean. On land the similar chain of food "supply .is interwoven across the surface only, or very close to it. In the sea it originates on the surface, but is by no means confined thereto; its links spread downward into the profoundest. depths, sometimes in the form of living animals, often as dead matter, sinking slowly to provide nourishment for the hungry creatures of tho middle waters and of tho distant ocean floor. "So it comes about that tho life of the depths owes its existence and continuance wholly to thtrt sun which, to the creatures living under that black pall of water, might be deemed as ineffective as the farthest star. . "The abundance of this minute life in the ocean,; not only t in the surface waters ,but far down into the depths, staggers the; imagination. A single cupful of water may contain, according to place and season, tens of thousands or hundreds of thousands of minute plants and animals. No less astonishing is their power of propagation, against which one may set their'wholesale destruction at the hands of the creatures that prey upon them. An ordinary marine bacterium will, in tho course of a week or two, under normal circumstances, multiply to' the" extent of several millions. On the other side we find that tho stomach of a single sardino has been estimated to contain 20 millions of ceratiumj ono of tho commoner infusoria, to , whoso presence phosphorescence in the sea is frequently due. "• '■'.■'.. ■ ::"Biiflargo figures convey a poor idea of- actual numbers*; when they pass beyond thousands it matters little whether they be millions or billions; the mind cannot envisage them. Suffice it to say that life in the sea, especially, but not only, among the smaller Organisms, its profusion; its fecundity, and tho destruction" to, which it is subject, 'is on a scale which beggars imagination;"