Chapter III: Introduction: I (2)

The eastern coast of North America has been divided into four sections, which correspond to the distribution of the algae which are characteristic of each section. The boundary-lines are not precise, since some species of each section extend beyond the defined limits; but arctic forms are not generally found south of Cape Cod, nor can tropical varieties be expected north of Cape Hatteras. On the intervening coast, however, there are some species common to both sections. The divisions are: (1) Greenland to Cape Cod; (2) Cape Cod to Cape Hatteras; (3) Cape Hatteras to Cape Florida; (4) the Florida Keys and the shores of the Gulf of Mexico.

On the Pacific coast such distinct lines of demarcation do not exist, there being no such natural barriers as are formed on the eastern coast, first by Cape Cod, and, second, by the stretch of sand-beach which extends from New York to Charleston, and which divides sharply the climatic varieties.

The whole shore is again divided laterally into three distinct belts, called the /littoral/, the /laminarian/, and the /coralline/ zones. The first or littoral zone covers the space between tide-marks. Vegetable life in this zone is subjected first to exposure to the sun and air, and even to desiccation, and then to entire submergence at constantly recurring periods. The rockweeds (/Fucus/), which are so plentiful in this zone, are very gelatinous, nature having apparently provided the gelatine to protect the cells of the plant from the effects of the alternating extreme conditions. /Fucus/ and /Enteromorpha/ predominate in this zone. [pg031]

The laminarian zone extends from low-water mark to the depth of fifteen fathoms. The /Laminariaceae/ and the beautiful red algae (/Florideae/) grow here.

The third or coralline zone extends to the depth of about fifty fathoms. The algae of this zone, the nullipores, are incrusted with a deposit of lime which gives them the appearance of corals; and, singularly enough, the corals, which are animal forms, simulate plant life.

Again, algae have special habits and demand certain climates and seasons for their growth. Algologists register the place where a specimen is found, and in this way localities have been pretty well determined. However, great exactness has not been reached, and the collector is ever watchful to find an alga in some undiscovered home within the given range. Although algae grow from extreme high-water mark to the depth of fifty fathoms, almost every variety may be found on the beach, those growing in deep water being frequently torn off and washed ashore by the waves. The heaps of sea-wrack will often reward one who examines them carefully for deep-water species. Seaweeds are most abundant on rocky shores, particularly where there are stratified rocks with crevices, which afford shelter from the waves. Rock pools often contain beautiful varieties of the more delicate species. Red algae will sometimes be found on the shady side of these pools. Sand-beaches are unfavorable to the growth of seaweeds, but fronds which have been carried long distances by the currents will frequently be found on such shores. [pg032]

IX

SOME PECULIAR AND INTERESTING VARIETIES OF ALGAE

The species of seaweeds that are known and classified are said to number several thousands. These plants, which have neither vessels for the conduction of fluids, nor fibers, consisting simply of the first vegetable element, the cell, have, notwithstanding this limitation, assumed a great variety of forms. In size they vary from one one-thousandth of an inch in diameter, the smallest green plants known, to those which exceed in length the height of the tallest trees and form dense submarine forests, which in places make comparatively deep water impassable for boats. In texture they vary from a jelly- to a paper- and a leather-like consistency. In color they have all the shades of green, brown, and red.

DIATOMS AND OTHER MINUTE ALGAE

Among the smallest algae are diatoms. They are microscopic in size, but exist everywhere in both salt and fresh water, and are infinite in variety as well as in numbers. They have a silicious, shell-like covering, which divides and subdivides in their reproductive growth, forming varied shapes which are exceedingly beautiful and interesting to examine under the microscope. In vast numbers they float on the surface of the sea, and, together with other minute free-floating organisms, form the basis of food-supply for fishes. Their indestructible shells fall to the bottom of the sea, forming large deposits, which in time become fossilized. The city of Richmond, Virginia, is built upon [pg033] a fossiliferous bed of diatoms, which measures twenty to eighty feet in depth and several miles in length.

Associated with diatoms, in fresh water, are desmids, which are green in color and resemble the diatoms except in having a cartilaginous instead of a silicious covering. Another minute organism, /Pyrocystis noctiluca/, is luminous and is said to produce the beautiful phosphorescent effects seen in tropical seas. /Trichodesmium/ is a little alga which periodically occurs in great numbers, giving the water a red appearance, as in the Red Sea, which is said to derive its name from this circumstance.

RED SNOW

In the high latitudes of the arctic regions, also on snowy mountains at altitudes where all vegetable life is supposed to be extinguished, there sometimes appears a redness on the surface of the snow, which in some cases extends for many miles. At a certain place in Greenland the color was so vivid that an arctic voyager named the locality the Crimson Bluffs.

The strangeness and almost sudden appearance of this color in the snow have been so unaccountable to uninformed observers that it has been ascribed by them to the falling of bloody snow and has been regarded with superstition. The redness is caused by the growth of one of the smallest of plants, the /Protococcus nivalis/. It is a simple one-celled alga containing protoplasm and endochrome (red coloring-matter). It grows by cell-division, the cell dividing into four, eight, or sixteen parts on a quaternary scale. Each part acquires a new covering while within the mother cell, and when it emerges it is a complete individual and ready to repeat the process. Only a few hours are required for its growth and development; hence its increase is rapid, and it requires but a little time to make itself manifest in those places where the conditions are favorable to its existence.

THE SARGASSO SEA

When the voyager reaches a certain region of the North Atlantic, called the Sargasso Sea, he sails into a vast undulating marine [pg034] prairie. Farther than the eye can reach is spread a yellowish-brown vegetation which covers the water as grass covers the plain. Sometimes these weeds are so thick as to impede navigation, and, seen from a little distance, seem substantial enough to walk upon. At other times, according to seasons and conditions of storm and wind, they are divided into strips or into island-like masses, with spaces of clear water between. If the sailor did not know the special conditions existing here he might suppose he had come upon dangerous shallows; or were the waters less turbulent he might dream that he was floating among the water-weeds of an inland lake.

This vast acreage of vegetation, as large as the continent of Europe, lying southwest of the Azores and extending between the Canary and the Cape Verde Islands, was first reported by Columbus, and takes its name from the floating plant of which it is composed, the /Sargassum bacciferum/, a species of the order /Fucaceae/, commonly known as gulfweed. Columbus's sailors took fright at the marvelous appearance and wished to turn back, thinking they had reached the end of the navigable ocean. They thought, if land were beyond, it was guarded by shoals, and that the weeds concealed dangerous rocks. Columbus threw out two hundred fathoms of line, but did not reach bottom, and continued on his course for fifteen days before emerging into clear water. From that day to this the Sargasso Sea has attracted the attention of all navigators. It is especially interesting to scientists. The physicist finds there the phenomenon of the ocean currents holding in a vortex this immense mass of seaweed, the zooelogist finds a great pasture in whose protecting shelter are living and breeding countless numbers of marine animals, and the botanist is puzzled because the source of this species of plant is clouded with doubt.

According to one theory, the plants are dislodged by the tempests from terrestrial beds and carried by the Gulf Stream into the huge eddy; but since there does not exist enough of the attached plants of this species to supply the vast accumulation, another and more generally accepted theory is that the gulfweed lives also a pelagic life and adapts itself to the conditions of the [pg035] floating state, thus dispensing with the disk-like root, as it needs no holdfasts, and propagating solely by lateral and axillary ramification.

There are said to be one hundred and fifty species of /Sargassum/, but /S. bacciferum/ alone constitutes the beds of the Sargasso Sea. The plant is the most highly differentiated of any seaweed, in that it more nearly approaches the true leaf and stem, and is described botanically as follows: Frond furnished with distinct, stalked, nerveless leaves and simple, axillary, stalked air-vessels. The integument is leathery, and the color brown of varying shades. The most striking peculiarity is the abundance of globular cells. These berry-like air-bladders give the plant buoyancy enough to support the weight of its innumerable guests. (Plate XVI.)

THE LAMINARIACEAE

In the laminarian zone, described above, grow the /Laminariaceae/, an order of brown seaweeds, some of whose genera grow to enormous size, and in some places form dense submarine forests. Darwin speaks of the good service rendered by these plants to vessels navigating stormy coasts, where often they act as natural breakwaters, and again as buoys designating dangerous rocks near the shore on which they grow. The seaweeds belonging to this order, commonly known as oarweeds, tangle, devil's-apron, and sea-colander, are frequently seen twelve to twenty feet in length, and others are measured by fathoms. One of the giant plants is /Nereocystis Luetkeana/, which occurs on the northwest coast. It has a stalk, sometimes three hundred feet in length, which bears on its extremity a barrel- or cask-shaped air-vessel, six or seven feet long, from the surface of which a tuft of fifty or more forked laminae grows to a length of thirty or forty feet. The stem which anchors this immense frond is so small that the Aleutian Indians use it for fishing-lines. The sea-otter makes his home on its huge air-vessel, and the plant is called by the Russians the "sea-otters' cabbage."

But the longest of all known plants is the alga /Macrocystis/. Its thin naked stem, the diameter of which seldom exceeds one quarter [pg036] of an inch, is reported by one author to be seven hundred feet in length, by another fifteen hundred feet. It is terminated by a lamina fifty feet long, resembling a pinnatifid leaf, each leaflet of which, at its point of division on the stem, expands into an air-vessel as large as an egg. These air-vessels sustain the immense frond which floats on the surface of the water, its leaflets depending in a vertical position from the stem. /M. pyrifera/, the only species, is found in the Southern oceans and on the Pacific coast of North America.

/Lessonia/, another genus, resembles a palm-tree. It grows erect to a great height and has a stem like the bole of a tree. It branches in a forking manner and has depending from its branches laminae two or three feet long. The large stems from which the laminae have been torn by the storms, and which have been cast ashore on the Falkland Islands, as described by Sir Joseph Hooker, resemble driftwood, as they lie in piles three or four feet high and extending for many miles.

/Agarum/ and /Thalassiophyllum/ are arctic genera, but they are found within our limits, the former in the North Atlantic. It has a simple but enormous leaf-like frond. The latter, which is found on the North Pacific coast, has a compound frond. Both are characterized by their fronds being perforated throughout with holes, giving them the name of sea-colander. [pg037]

X

USES OF ALGAE

Water covers two thirds of the surface of the earth, and algae, with a very few exceptions, constitute the whole vegetation which exists in that enormous area. They have, therefore, an important part to perform in the economy of nature. Algae do not, like land plants, derive their nourishment from the soil to which they are attached, but from substances held in solution by water. In their growth they effect changes in the water analogous to those effected by land plants in the air; that is, they change so-called impurities in the water into materials essential to animal life. The function of plants is that of transforming or manufacturing inorganic matter, which they assimilate, into organic matter (such as starch, albumen, sugar), which forms their own structure and which is the food essential to animals. In this process, plants inhale carbonic acid gas which animals breathe out, and exhale oxygen which animals breathe in. Plants feed on mineral substances and furnish vegetable food, thus keeping up the balance of life.

Fresh-water algae have a like economic value. The green surface on stagnant pools is a vegetable growth whose function is to assimilate the matter which makes the pool offensive. A submerged district soon becomes covered with scum, or minute plants (/Sphaeoplea annulina/), which grow with great rapidity, using up the materials of the decaying vegetation, and in great measure counteracting the ill effects, in the atmosphere, of such decay. When the waters subside, the plants shrivel up and appear like thin paper covering the ground. This ephemeral substance soon [pg038] disappears, without giving evidence of its nature in dust or gases, its body seeming to be a machine which transmutes, but does not hold, the substances on which it grows.

Algae, as has been said above, grow in definite zones, and each zone has also a definite animal life which finds there its food. Darwin says: "In all parts of the world a rocky and partially protected shore perhaps supports in a given space a greater number of individual animals than any other station." And speaking of the /Laminariaceae/, he adds: "I can only compare these great aquatic forests of the southern hemisphere with the terrestrial ones in the intertropical regions. Yet if in any country a forest was destroyed I do not believe nearly so many species of animals would perish as would here from the destruction of the kelp." The same may be said of the Sargasso Sea, where millions of living creatures make their home. In every kind of marine fauna there are species which derive, if not the whole, at least a part of their nourishment from the seaweeds.

The vegetation in the narrow boundary of the three zones is palpably inadequate to supply the needs of the animal life which exists in deeper waters. But over the broad area of the ocean there exists a vast number of pelagic, free-floating algae, which, although microscopical in size, are almost infinite in numbers. In illustration of this it has been estimated that, although they are not especially numerous in the Sargasso Sea, yet if all the seaweed there were gathered into one mass and the free-floating algae into another, the bulk of the latter would exceed that of the former. The pelagic flora consists of /Diatomaceae/, /Protococcaceae/, /Peridinieae/, and others. Undoubtedly it is on these pastures that fishes feed, as well as other organisms which in turn are food for fishes.

/Fucus/ and /Laminaria/ constitute the kelp from which iodine is obtained, and were at one time the source of the potash of commerce. /Fucus vesiculosus/ is a constituent of a medicine used as a cure for obesity. /Chondrus crispus/, commonly known as Irish moss, was a few years ago generally used as an article of diet. /Porphyra vulgaris/ (laver) is used by the Chinese for soups. /Rhodymenia palmata/ (dulse) is an article of food in Ireland and Scotland. [pg039] /Gracilaria spinosa/ is used by birds, allied to the swallows, for making their nests--the edible nests found in large numbers on the islands of the Indian Archipelago, especially in the caves on the shores of Java, and gathered and sent to China, where they bring large prices and are used in making the famous birds'-nest soup. /Gracilaria lichenoides/, also a species of the Eastern seas, is the source of agar-agar, a preparation used in laboratories as a culture-medium for bacteria. Fossil diatoms are ground and used for polishing-powders. Seaweeds are everywhere used by farmers on the coasts as fertilizers. [pg040]

XI

COLLECTING AT BAR HARBOR

The beautiful coast of Maine is a particularly good field for shore-collecting. The rocky coast harbors the boreal fauna and flora which depend upon such physical conditions, and the shores at Bar Harbor are typical of those found elsewhere in northern New England. The rocks give shelter from the beating surf, while life has exposure to the cold, pure waters of the arctic current. Everywhere along the shore, rock pools are to be found. These are perhaps the most fascinating of all spots to the collector. They are veritable gardens of the sea, where species flourish which naturally belong to deeper water, but which find in such pools conditions suitable to their existence.

At Bar Harbor one well-known and frequently visited rock pool is found in Anemone Cave. Entering a field at Schooner Head, one turns to the right and follows the rocky shore for two or three hundred feet. It is difficult to take this short walk without being constantly diverted and delayed by the various attractions one meets, such as the tide-pools, the barnacles which in places whiten the rocks, the periwinkles, the purpura shells, and the curious algae; but at last one arrives at a cavern under an overhanging rock. Here is a large tide-pool which at first sight displays only a beautiful scheme of color. It is carpeted with a bright-pink alga, /Hildenbrandtia rosea/, which incrusts the basin of the pool.

Interspersed with the pink are patches of a deep-red color, having a velvety appearance, which are formed by another crustaceous alga, /Petrocelis cruenta/. The water of the pool is of crystal [pg041] clearness, and as one gazes into it one object after another comes into view, until one is filled with astonishment at the number of beautiful objects the pool contains. The little green balls, one half of an inch to one inch in diameter, which look like small green tomatoes scattered on the stones, are /Leathesia difformis/, an alga which cannot be mistaken for any other. Bunches of /Corallina officinalis/, which resembles coral, as the name indicates, are abundant. This alga should be examined with a magnifying-glass. It is covered with calcareous matter, and its peculiar form of growth is beautiful and interesting.

The fronds of the laminarian /Alaria esculenta/ are tiny here, while just outside the cave they are to be seen several feet in length, beating against the rocks in the swash of the waves. Thorny sea-urchins (/Strongylocentrotus drobachiensis/) make green spots which look like tufts of moss. Yellow and green sponges in little cones are spread over small surfaces. Starfishes and ophiurans are plentiful. The /Purpura lapillus/ and /Littorina litorea/ and /rudis/ (periwinkles), so plentiful on this coast, are present. The /Mytillus/ and the /Saxicava/ and the /Acmaea testudinalis/ are also to be found. A green crab (/Carcinus maenas/) is snugly hidden in a dark nook on the shady side of the pool, and many small crustaceans scuttle away from under stones as they are lifted. The collector is always anxious for uncommon, or rather less plentiful, species, and here are found two specimens of nudibranchs, or naked mollusks, /AEolis/ and /Dendronotus/. The /Chiton ruber/, a jointed mollusk, was also found here, and five species of sea-anemones were counted. As this is a favorite hunting-ground, the anemones have not been left to attain full growth; but there are very many small ones which at first are not distinguishable, as they retract their tentacles at the slightest disturbance of the water and are then quite inconspicuous. After a little time of quiet watching they will be seen putting out their tentacles and expanding their beautiful flower-like forms. It is useless to try to capture them uninjured, so tightly do they adhere to the rocks, and the difficulty of preserving them in an expanded form is so great that amateur collectors had better leave them undisturbed to beautify the pool. [pg042]

It was hard to resist robbing this rock pool, where the author in half an hour counted twenty different species, and finally left, feeling that its treasures were not half discovered; but collecting should be done elsewhere, and this pool be guarded as a gem to be admired and not to be despoiled.

This pool in Anemone Cave, although so very attractive, is surpassed in beauty and interest by pools on Porcupine Island, at the base of the cliff. This place is somewhat difficult of access, and the timid will not undertake the descent to it; but the enthusiastic collector, who overlooks small obstacles, will be repaid by a visit to this spot, where all the treasures of Anemone Cave are multiplied many times over. These pools are resplendent with large anemones, hydroids, nudibranchs, mollusks, echinoderms, crustaceans, and algae. /Alaria esculenta/, several feet in length, is beaten to a fringe against the rocks, and /Agarum Turneri/, the sea-colander, is also found here, together with beautiful specimens of /Rhodymenia palmata/, which is so plentiful that it reddens the rocks.

A /Metridium marginatum/, the most common sea-anemone of this coast, was taken here which measured six inches in diameter. This creature threw out so many of the processes used for defense that it seemed at first as though it were covered with some seaweed; but the worm-like movements of these threads, which measured six inches or more in length, soon disclosed their nature.

On the more accessible shores of Porcupine Island are found the naked mollusks (nudibranchs) /AEolis/ and /Dendronotus/. Clinging sideways to the rocks just above high-water mark are many shells of /Littorina rudis/. They are fastened to the rocks by a glutinous deposit along the outer lip, and the peculiar exposure of the open end, as well as the position above tide-mark, indicates that this animal is undergoing transformation into a land species. /Littorina palliata/ is abundant on the rockweeds (/Fucus/); some of the specimens are banded with yellow, and all closely simulate the seaweed on which they cling. Beautifully banded specimens of /Littorina litorea/ are also plentiful. Among other shells which are abundant here as well as elsewhere on this coast are /Purpura lapillus/, /Acmaea testudinalis/, /Buccinum undatum/, /Mya arenaria/, and /Mytillus edulis/. [pg043]

Under the rockweeds in small pools and crevices are the polyzoans /Bugula turrita/ and /Membranipora pilosa/, and the hydroids /Sertularia pumila/ and /S. argentea/.

The seaweeds /Rhodymenia palmata/ (dulse) and /Desmarestia/ are plentiful; also beautiful worms, crustaceans, and starfishes.

A very interesting beach is found a few hundred feet south of Otter Cliffs, to which an easy descent is made if one follows a pathway leading to it through a grove adjacent to the drive. Here one will be interested in the study of numerous and beautiful rock pools.

Sea-urchins (/Strongylocentrotus drobachiensis/) seem to carpet some of them, having the appearance of mossy tufts. Beautiful pink and purple starfishes (/Asterias vulgaris/), brittle-stars (/Ophiopholis aculeata/), sea-cucumbers (/Pentacta frondosa/), sea-anemones, and crabs are abundant. If one lifts a stone the little crustaceans /Orchestia/ and /Gammarus/ will hurry away, and very likely an interesting worm or a nudibranch will be found. It is also most interesting to watch the barnacles, which are below the surface, reaching out their curled, feather-like feet in regular rhythmic grasping motions. The common mussels (/Mytillus edulis/), which in places blacken the shore, are beautiful under examination, and the silky network or byssus which forms the anchorage should be observed.

The rocks are hung so plentifully with /Ascophyllum nodosum/ (rockweed) that its beauty is likely to be passed over unnoticed. On the /Ascophyllum/ is growing in tufts /Polysiphonia fastigiata/; other seaweeds, /Rhodymenia palmata/, /Chordaria flagelliformis/, /Desmarestia aculeata/, /Corallina officinalis/, and /Ceramium/, are so abundant that one forgets to value them at the moment. Higher up on the beach the rocks are spotted with papery sheets, which, floated out in water, prove to be the beautiful purple /Porphyra/. A fine, dark colored, hairy scum on the rocks is /Bangia fusco-purpurea/. Sometimes one finds here fronds of /Laminaria/ which have been washed ashore. Various green algae are abundant. Even if not collecting, it is well to carry a small tin pail to the beach and float out pieces of the algae in order to observe carefully, if but for a moment, the beautiful forms they have in their natural state. Watched for a few minutes in a pail of water animals disclose curious [pg044] and surprising forms and habits which are difficult to watch leaning over a pool.

Most of the various species mentioned above are common along the whole shore, and may be looked for at almost any point where the water is free from contamination.

At the sand-beach are found species which do not inhabit the rocky shore, as the sand-dollar (/Echinarachnius parma/), /Polynices/ (/Lunatia/) /heros/, /Mya arenaria/, and others. After a storm various deep-water forms are washed upon this beach. /Laminaria digitata/, six feet long, is found here sometimes under these circumstances. /Chordaria flagelliformis/, resembling long switches of hair, floats from the rocks near the shore. To the left, on the rock under the overhanging ledge, is a tide-pool which one would hesitate to deface by touching a single specimen. So crystal-clear is the water, so brilliant the /Hildenbrandtia/, so lovely the /Corallina/, that all seem placed there to excite admiration.

But most of all one should obtain the permission of the owner to visit Rodicks Weir. Here is an immense natural aquarium, full of living wonders. On a clear day, sunlight penetrates to the bottom, and at low tide the whole contents of the weir are clearly seen as one floats through the inclosed water-spaces. On the bottom are sea-urchins, many of them with sticks or stones on their backs, which the animals have placed there in the endeavor to conceal themselves; starfishes feeding; and great numbers of whelks (/Buccinum undatum/). Cuttlefishes dart rapidly about, and skates, sculpins, and other fishes display their curious forms. Very likely a giant jellyfish (/Cyanea arctica/) is entangled in the brush, so that one can examine at short range its wonderful and beautiful parts. Other jellyfishes may be closely scrutinized.

The alga /Polysiphonia violacea/ floats in long feathery tufts from the stakes.

On the eel-grass are to be found /Lacuna vincta/ and the delicate iridescent little shells of /Margarita helicina/.

Every tide brings different species of the ocean fauna to temporary imprisonment in this inclosure, so that it is difficult to say what one may not chance to find in this interesting place.