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Ocean-Weeds

( Originally Published Early 1900's )



SCATTERED through the vast Chalk-beds of Great Britain and the Continent of Europe are thousands of layers of FLINT, such layers as any of us may have seen intersecting the smooth white face of Chalk Cliffs. And as with Chalk, so with Flint—we at once find ourselves upon the track of Life.

Not indeed always of animal life. Sometimes vegetable life takes its place. Though the highest Vegetables stand on a lower level than the lowest Animals, they too have Life, and thereby they are entirely apart from the whole world of inanimate Nature.

Widely distinct are the Animal Kingdom and the Vegetable Kingdom ; yet on the borderland between the two is found a hazy belt of uncertainty.

So gently does the one glide into the other that, though a line of demarcation does exist, it is not always easily made out. But the transition from the lowest form of that which lives to any and every form of that which has no Life is abrupt, absolute, precipitous. Here we see no quiet sliding of the one into the other, no wavering hesitancy as to whether a certain something may belong to' this or that side of the dividing parapet.

The term "Vegetables," used scientifically about Land Vegetation, includes all manner of growths, from the lichen to the forest tree. But by that word, used in connection with the Ocean, is meant, not cabbages and cauliflowers, not garden-plants or forest-trees, but an enormous variety of Sea-Weeds.

And among ocean-vegetables of humblest form, flourishing in salt water, is that of Diatoms—Flint-makers.

It need not be imagined that the manufacture of Flint is a monopoly of the Diatom tribe. That would be a mis-take.

There are small carbonate-of-lime building jelly-specks and carbonate-of-lime building jelly-polyps. But there are also little vegetable-growths in the sea which form carbonate-of-lime, and some of these add their quota to the work of rearing Coral-reefs.

We have now to do with small flint-building vegetable-growths. But there are also little animal jelly-specks in the sea which form flint.

So neither Carbonate-of-lime nor Flint can be spoken of as belonging only to Animal or only to Vegetable Life. They must both be described in general terms as the out-come of that which Lives.

Among other Flint-builders in the ocean are the Radiolarians, living jelly-specks, and makers of the most exquisite shells, so tiny in size that millions of them may be packed into one cubic inch. These belong to the Animal Kingdom. They rank with the Foraminifera, differing from them chiefly in the fact that their shells or skeletons are formed of silica, not carbonate-of-lime.

But in this chapter we are concerned with the Vegetable Life of the ocean, and we must therefore let the wonderful Radiolarians alone.

Properly the chapter on Vegetables ought to have come before any chapter on Animals, since we have been climbing upward from inanimate Nature, and since all vegetables rank below all animals. When on the topic of Ocean-building, however, the subject of Chalk seemed to follow naturally after that of Sandstone.

No surprise need be felt at vegetables being able to make or secrete" flint and chalk. This making is, as we have seen, an unconscious work. The living jelly-speck secretes automatically, not with intention.

Such secreting is not confined to ocean vegetables.

Trees and plants on land manufacture a host of substances—sweet oil, cocoanut milk, indiarubber, and count-less others.* Forest trees in like manner grow their own framework of hard wood, which may be said to take the place with them of a skeleton.

All this is a part of LIFE. Inanimate rocks and stones may lie for centuries unchanged, except through friction with other rocks and stones, or with running water. But where Life reigns, though it be of the simplest kind, there growth and development must follow.

Life, from its very nature, cannot mean stagnation, or standing still. It must always be assimilating. It must always be expanding. It must always be doing. When these things cease, death has begun.

So much alike are the lower forms of life in the two classes, that many an animal has been for a time mistakenly called a vegetable, and many a vegetable has been for a while supposed to be an animal. The foraminifera were once ranked as vegetables, and the diatoms were ranked as animals.

In deep-sea regions, dark and cold, no vegetable life can possibly exist, not even the almost ubiquitous diatoms. As the tiny plant-life dies out, the little hard vegetable-cases sink to the ocean-bed, there to mingle with gathering muds and oozes—there, too, in the course of ages, to be transformed into Flint.

Diatoms flourish on land as well as in the ocean; in cold climates as well as in warm. On the whole they prefer the colder regions, therein differing from the warmth-loving foraminifera. Sometimes immense floating banks of these microscopic plants are found, reaching through many miles. A net, lowered into such a bank and then drawn up, is filled with a "brown-colored slimy and felt-like mass," made up chiefly of uncountable myriads of diatoms.

Such masses are held together by a kind of sticky jelly, and if the hand is passed through it a very slight roughness may be perceptible, caused by the flinty diatom shells or cases.

Mere specks indeed they are, individually too minute to be seen by a human eye, unaided. Yet how marvellous in their make !

A Diatom plant or vegetable or sea-weed, whichever we choose to call it, is like a Foraminifer of the simplest possible structure. It consists of a single cell, with an outside flinty coating or inclosure, answering to the wood of a tree or the skeleton of an animal.

This flint casing, though infinitely small and delicate, is yet firm enough to prevent the passage of water through it; and also it is practically indestructible by ordinary forces. Diatom-cases, dropping to the ocean-bed, may lie there for ages.

The living cell is inclosed in the said "case," which is a kind of box, consisting of two halves or "frustules," neatly joined together by a ring or girdle.

Diatoms increase in numbers, like many of the Foraminifera, by simply dividing into two. When the living cell thus parts, each half takes as its share one side of the box, and each then makes another side, or "frustule," to complete itself. For this operation, the tiny ring or hoop doubles into a pair of hoops, one of which clings to each half of the case.

Perhaps in all the world no greater marvels are to be seen than these extraordinary minute vegetable-cases.

Minute? Yes. A mass of millions upon millions, held together, may be perceived and felt. But let a light scattering of them be dropped upon a slip of grass in broad daylight, and let a man of keen eyesight set himself to examine them. Ile will see—nothing ! Not even an appearance of delicate dust. The diatoms are to him as if they did not exist.

Then let him put that fine scattering under a good microscope, changing lens after lens, to higher powers. A world of beauty, of finish, of originality, of unbounded variety in construction, will open out before him.

Each little shell is exquisitely shaped, exquisitely put together, exquisitely ornamented. Though thousands, nay, millions, of them might be packed into a cubic inch, yet there has been no carelessness, no scamping, in the work, no saying, "Nobody will see, so anything will do."

The different kinds of Diatoms are innumerable; and each kind, each species, even each variety, has its own especial form, its own complex design, followed out and faithfully reproduced in hundreds of millions of individuals.

Pattern-markings, by which each variety is distinguished, formed of an infinitude of delicate lines and dots, arranged in every imaginable fashion, vary to an extent almost beyond conception. There are cases round, tri-angular, lengthy, many-sided, chain-like—but to picture them in words is hopeless. They have to be studied in their own wonderful minuteness and delicacy, complexity and loveliness, before they can be known. . . .

It seems that every individual of every separate kind has power to form certain shapes, with certain markings, and no more. It is as if upon each minute speck of vegetable life had been originally impressed its own—not individual character, but class character. This character unconsciously expresses itself in such and such a form of shell, just as with men the individual character expresses itself in such and such outlines of face. The same may be said of Foraminifera and Radiolarian shells.

Some Diatoms have a singular power of movement; and from this sprang early mistakes, through which they were wrongly classed as animals.

Many of them grow, like ordinary plants, fixed in one spot. But many others are in continuous and regular motion. Careful study has, however, made it clear that the movements of Diatoms are purely mechanical, purely involuntary, like those of some sensitive land-plants. It is probably due to the working of food, taken into the little organism, and not obedient to any Will on its part.

It may be that herein lies the great difference between a Diatom and a Foraminifer. The one exists, but has no approach to consciousness ; or, at least, probably no approach to any power of choice. The other, though of the very lowest and feeblest type of Animal-life, may yet be supposed in its infinitesimal measure to have a wish, and to be able to act upon that wish. But here we do not get beyond conjecture. Where Life exists, it may be that in all cases some dim form of consciousness exists also, which may involve some faint power of choice.

Flint-making, like Chalk-making, is not only an old-world and long-past operation, but a present one. Diatoms lived and died in ages gone by, and their remains are found hardened into flint. Diatoms live and die in these days ; and their remains may yet, in centuries to come, be transformed into the same substance.

From Diatoms one might range upward through an enormous variety of Ocean-weeds, of all kinds and descriptions.

Though they are the "last and lowest of all the tribes of plants," yet it is a wide step from the undermost to the uppermost of even this humble Vegetable Tribe.

At least five or six thousand species of Sea-weeds are known to Naturalists. Each ocean, each lesser sea, has its own particular vegetation, largely affected by the varying degrees of saltness, the warmth or coldness of the water, and the faster or slower currents which hap-pen there to prevail.

Sea-weeds of all sizes are found, from the invisible diatoms to enormous growths in Pacific waters, reaching to yards upon yards in length, with solid trunk-like stems, and huge fronds like those of a tropical palm.

Near Tierra del Fuego immense growths have been seen, with stems between three and four hundred feet in length. Great sub-ocean forests of kelp are there, and floating fucus-islands, with leaves or fronds seven or eight feet from base to tip, covered with living animals, and having air-vessels several inches long.

In the matter of color no great variety exists. Sea-weeds are generally either grass-green, olive-brown, or red. The green are usually close to land, and they never grow beyond touch with direct sunlight. The olive-brown are the more abundant ; and the red belong, perhaps, more often to deep water.

A large majority grow attached either to stones or to the shallow sea-bottom, but some kinds float unattached.

To this last class belong the masses of weed in the Sargasso Sea—the centre of the North Atlantic currents.

Round that huge collection of weeds and drift, which reaches over something like two hundred and sixty thou-sand square miles, the entire North Atlantic slowly revolves. And of these weeds-called "Sargassum"—none are attached to rock or ground, but all float loosely in mid-ocean. They seem to flourish thus, though the fact that fructification is not found upon them points to a somewhat unusual condition of things.

Sea-weeds more often multiply by means of spores, —a form of vegetable-growth inferior to that of seeds. All spore-growing plants, whether on land or in the sea, take a lower rank than seed-growing plants.

A still lower and humbler method is that of simply dividing into half.

There is yet another way by which ocean-weeds in-crease, and it reminds one curiously of the gardener's plan of growth by cuttings.

In rough weather, on shallow reaches not far from land, the waves tear quantities of sea-weed fronds from their moorings, and carry them to shore or to rocky parts, where they become entangled, and are held fast.

There, if later waves do not again dislodge them, and if other circumstances are favorable, the wandering fronds settle down, attach themselves, and become fresh plants. So in this case the waves act as gardeners, and make cuttings of ocean-plants.

While plant-life in the ocean is plentiful in amount and abundant in variety, it is confined within limits. By far the greater part of Sea-weed existence is contained in the Hundred-fathom limit—that is, within six hundred feet of the surface. Not many kinds, indeed, can grow in anything like as much depth as five or six hundred feet.

Sea-weeds in abundance are found on shallow shores, near continents and islands ; on the zone between high and low tides; and on gently-shelving slopes beyond that zone.

Were formerly accounted to be: (1) The pyramids of Egypt, (2) the hanging gardens of Babylon, (3) the tomb of Mausôlos, (4) the temple of Diana at Ephesus, (5) the Colossus of Rhodes, (6) the statue of Zeus by Phidias, (7) the pharos of Egypt, or else the palace of Cyrus cemented with gold.



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