Floating Meadows.

Waikato Times, Volume 107, Issue 17976, 22 March 1930, Page 1 (Supplement)

Floating Meadows.

WE have just had the pleasure of crossing the Atlantic, but we were greatly disappointed by the sparseness of life, compared with what we had seen on previous occasions in the same waters. Perhaps we expected too much in midwinter. for the seasons take a grip even on the open waters. There Is a very prolific multiplication of smalt surplace plants and animals in 'the spring months, and this, of course, accounts for the summer increase of larger animals. Diatoms and Infusorians microscopic in their dimensions and inconceivable, (though not incalculable) in their numbers, afford sustenance to small free-swim,ming or drifting crustaceans, e.g., Copepods; and these again form the staple food of many Open Sea animals of higher degree such "as the daintily-feeding mackerel. Many of the nutritive chains are much longer than this.

Winter Scarcity. In October there is another outburst of microscopic plant life in the ocean, but ,p, j S not so striking as that of spring, and it dies away rapidly. Then follows the scarcity of winter. As Russell and Yonge say in their fascinating book, “ The Sea," .(Warne, 1929), the best of all compact Introductions to an attractive subject. “ Qnlv a small number of animals survive to tide over the lean months and give rise once more to their numberless progeny in the following spring when the sea w'akes up from its winter sleep." It is easy enough to catch sight of an ticcasional Storm Petrel or Spouting Whale, hut we suspect there were few passengers on board the Mauretania that saw one livin'- creature for each of the five to six days the “ocean greyhound", took in its race, not only is mid-winter a lean time, but the rough weather that beset us is much against the observation of marine life. Apart from the observer’s poise, the white horses hide everything, and there are many pela'dc or Open Sea animals which sink to quieter depths when the waves begin to break. Starving Sea Birds. Few animals that are not very small or very compact can endure being violently lifted high in the air and then scattered explosively in the gale. Of very delicate creatures like the sea-gooseberries or ntenophores, it is well known that they he-in to sink whenever a white horse shows its face. One of the consequences of this life-preserving sinking habit is that Open Sea birds, such as guillemots, razorbills and gannels, find it difficult to obtain sufficient food in stormy weather. Even ttiouch they are abld to dive they may not be able to descend far enough to secure their booty. Then they become weak and fatigued, and may be battered t-o death in a haunt where they arc usually so much at home. , But it Is only when the storm is prolonged for several successive days that the pelagic birds suffer badly; and, as Mr as we know, the Storm Petrel or Mother Carey’s Chicken, the smallest of webfooted birds, is almost invariably succe^s-

Teeming Life of the Atlantic.

(Prbfessor J- Arthur Thomson)

fu'l in its conquest of the most adventurous of ail habitats. Without labouring our apology for having on this occasion seen so little on our voyage to New' York, we may he allowed to add that from the zoological point of view, the vessel was going far. too rapidly 1 In most cases, In the realm of Natural History the quicker you go the less you seeThe useful words “ plankton ’’ and “ nekton ” w'ere invented by Ernst Haclcel to designate those creatures that drift and those that swam in the open waters- But the contrast must not be pressed in a hard-and-fast way, for many of the Plankton creatures can swim a little, though not In the energetic masterful way that Is characteristic of the Nekton. Ooeanlo Swimmers. Amongst the oceanic swimmers might be mentioned the whales (the giants of the Nekton), the pelagic birds (all, of course, also able to fly except the penguins of the Far South), the Open Sea carnivorous turtles and the sea-snakes with their flattened tails, many of the fishes (including both the full-grown and the larval eels on their long journeys), a few' energetic Tunicates like Salps and Fireflames, some of the squids and many crustaceans, and then a crowd of animals of humbler rank, such as certain free-swimming w'Orrns, which may be said to “ command their course," for this is the test of a true member of the Nekton. As to the plankton, the bulk of it Is microscopic, yet some of the leisurely jellyfishes, which never swim more than gently, may have tentacles thirty feet long and discs on which a mermaid might try to balance h-erself. The delicate mulluscs, called sea-butterflies, on which the whalebone whales largely depend, are typical members of the plankton. So are' the larval stages of many inshore fishes and of many littoral animals, so delicate in their youth that they could not survive for a day In the rough-and-tumble conditions where they flourish when they grow up. Of fundamental importance are the small pelagic crustaceans which swarm in numbers scarce credible. A Deep Practical Question. Thus in a quarter of an hour a single silk tow-net drawn through the water in the w'ake of a boat may capture over two million specimens of Calanus, a small crustacean on which many fishes feed. Most important of all are “ the floating seameadows” of Diatoms and other singlecelled plants on which l.he pelagic animals ultimately depend. The vitamin of codliver oil is primarily manufactured by pelagic Algae, though these are not directly eaten by codfish.

We cannot, think of the drifters and the swimmers, the Plankton and the Nekton, without realising that they represent a universal \ alternative, a deep dichotomy or parting of the ways, which every one of us has to face, between easy-going acquiescence with environing currents or effortful swimming against the stream- Are we planktonic or nektonic? That is the deepest of practical aueslion*-