The Seven Mysteries of Life

by Guy Murchie

  The whole superorganism of three kingdoms of interrelated life that is a dune parades thus steadily onward before the swirling wind, devouring trees in its path, some of whom may live completely submerged (like poplars 80 feet high inside dunes on the coast of Holland or custard apple trees in the Brazilian desert). In fact a large dune may swallow a whole house and, in rare cases, even a small village, which it voids behind it a few years later. And its character betimes changes according to the environment, its progress and development ultimately slowing to a stop (after a century or a millennium) whereupon it dies as vegetation finally anchors its sand in place and it can do nothing further but fade back into the landscape of the countryside.

  BEACHES

  Something similar happens in the case of an ocean beach, obviously akin to the dune although usually much larger in at least one dimension. Beaches indeed are as much organisms as dunes are and about equally dynamic and sensitive to wind and weather, the main difference being that most beach motion takes place underwater and is therefore not generally noticed. The material of beaches, moreover, is more varied than that of dunes, for practically any kind of plentiful object heavy enough to settle and pack yet small enough to be moved by the sea may form a beach. Beaches are known to be made of white quartz powder, of black lava cobbles, green basalt pebbles, crushed yellow sea shells and ground pink coral. There are beaches of coal dust along the Ohio River near Pittsburgh along which dance dainty dusky "coal pipers." And I have heard of a "pocket beach" at Fort Bragg, California, composed of nothing but crumpled tin cans washed in from an oceanic dump. It is rather wonderful, I think, that these old cans, which once stocked shelves in a thousand kitchens, can be literally tossed about and arranged by the wild waves into the same familiar formations of natural beaches made of sand.

  The main reason beaches are dynamic is that waves and the sea bottom change each other as long as the wind, tides and currents keep them moving. As a wave approaches shore the increasing shallowness cramps the gyrating H2O molecules beneath it, squeezing their orbits and forcing the wave to break and become a carrier of water. As seas rise in a storm their roots roil the bottom and raise corresponding sandbars which in turn lift the waves still higher. The shape of one influences the shape of the other through continuous motion and feedback - wave to bottom to wave to bottom to wave - and there are short-term and seasonal rhythms to it. Winter storms steepen and wash away much of the berm (the part of the beach above normal high-tide level), the material of which helps build the offshore sandbars, but summer breezes patiently widen and restore the berm again, keeping it at a remarkably consistent average of 1.3 times the height of recent waves. As in dunes, the grains thus are continually winnowed and sorted, the coarse ones going to steep beaches during the storms which keep the finer grains suspended in the turbulent waves and the small ones eventually being allowed to settle on the flat berms which grow mostly during the calm periods.

  There is also a ceaseless sideway movement of material along the beach often featuring cusps or small peninsulas separated by creeping crescent-shaped bites out of the shore, anywhere from 6 inches to 400 yards apart. Despite human efforts to stem this littoral flow by building walls, called groins, perpendicular to the shoreline every hundred feet or so along a beach, the fact that sand grains rolling only one tenth of an inch per wave can travel up to five miles in a year means very drastic changes to a coast in a century.

  In the long run of course the wind, using the sea as its tool, prevails over any such limited measures, and much of North Carolina's storm-racked outer banks is dissolving into the Atlantic at the rate of fifteen feet a year. This happens because along the east coast of America the sea takes away more sand in winter than it gives back in summer, a net erosion that is abetted slightly by the gradual melting of the Earth's massive glaciers in Antarctica, Greenland, etc., in the 12,000 year post-ice-age thaw which has ever since made the ocean level rise about three feet a century. Much faster is the movement of an offshore bank such as Fire Island, New York, which has been measured to drift downwind (southwestward) before northeast gales to the tune of 7 inches a day, 212 feet in an average year or more than 4 miles in the past century. This is faster than the tip of the hour hand of the average watch.

  ISLANDS

  The birth and death of common sandy islands under wind and tide are tame compared with the dramatic antics of the rare volcanic ones that may appear or disappear in an explosive flash or, more likely, in a prolonged outpouring of lava and brimstone. On the morning of November 14, 1963, to take a recent example, a fishing vessel was cruising four miles west of Geirfuglaskur, then Iceland's southernmost offshore island, when the skipper, the engineer and the cook all felt their boat sway "as if caught in a whirlpool" and noticed a strange smell of sulfur fumes. Soon a black plume of smoke belched up from the sea a few miles to the south, and the awesome spectacle of a subsea volcano giving birth to an island transpired before their eyes. The pangs were understandably violent, with jets of steam and gas and ash a hundred feet in diameter shooting two miles into the sky. More important were the uncountable chunks of cinder and tephra which were hurled thousands of feet through the clouds before they plummeted down upon the ocean in such a relentless barrage that by evening the basalt bottom (originally 425 feet down) had become a great hissing undersea hill that piled up hour after hour until it broke through the waves and at dawn stood 33 feet above them. Four days later Pluto had so decisively gained the upper hand in his battle with Neptune that the infant isle was puffing and basking like a giant sea lion, its black crescent shape looming 200 feet high and 2000 feet from tip to tip, while the steam and smoke, now billowing five miles up from a huge crater, had burgeoned into a perpetual thunderstorm flickering with lightning and growling like the legendary Norse giant for whom the land was about to be named Surtsey.

  Once the crater walls were strong enough to hold back the sea, lava began to well up inside them, spilling over in rivers of fire that rapidly coated the island with a tough basaltic crust not unlike the bark on a tree. This began when the island was five months old and continued for three years until Surtsey had achieved the noble stature of 567 feet in height, a length of 1.3 miles and an area of more than a square mile, or twice that of the principality of Monaco.

  Meantime the baby island, having already felt the precocious tread of man (when scientists landed the first month), spontaneously arid permanently integrated the animal and vegetable kingdoms into its life. It did this very casually, almost indifferently, long before the first lava appeared. Came a blustery winter day when a tired gull alighted and the following week seaweed quietly attached itself to a rock. Early the first spring, flies and springtails and mites blew in on the north wind, and in June a kittiwake nested on the side of a six-month-old cliff. About the same time sea worms, crabs, mollusks and innumerable smaller creatures began to wriggle and crawl on the beginning of a beach at low tide. By the summer of 1967 hundreds of different kinds of plants had rooted themselves in crannies, and the sooty cliffs were aflutter with birds. The first flower, after two heroic years of repeated burial in ashes, bloomed in white upon the glassy purple sand. It was a sea rocket (Cakile edentula) whose gallantry signalized the future luxuriance of this extraordinary superorganism of a volcanic island. And the island exists as a surviving sprout in the almost continuous budding of new islands (most of them abortive) along the mid-Atlantic ridge, which ridge in turn composes a seam (apparently rising) among the ever-moving platelike sections of the living Earth.

  Volcanoes, you see, also live their lives, which, like those of stars, tend to be long even if occasionally explosive. Land volcanoes are the better known but undersea ones are coming to be studied more and more. Called seamounts, they grow while gradually drifting away from the mid-ocean ridge where most of them (like Surtsey) were born, intermittently spewing lava, which is their version of cell division. For tens of millions of years this activity (now called plate tectonics) has continued fitfully as the se
a floor spreads out on both sides of the ridge, flat-topped guyots (undersea buttes) eventually pupating (with the aid of coral) into quiet atolls in volcanic old age.

  GLACIERS

  An eccentric cousin among these rowdy Earth fry is the volcano that erupts below a large glacier. This occurs periodically in Iceland, for example, and inevitably melts out a huge pocket of water right above the lava and which, when it finally gushes through the surrounding ice, may roar at deadly speed across the countryside in a headlong, steamy flood known as a jokulhlaup, with boulders and icebergs bowled end over end in the raging torrent. A particularly devastating jokulhlaup in Grimsvotn, Iceland, in 1922 released an estimated 1.7 cubic miles of water in four days, which, had it reached a densely populated area, could have drowned tens of thousands of people!

  Although a glacier seems utterly inert compared with such a flood, it is by no means completely dead, its apparent "lifelessness" being a human illusion obviously attributable to the relative swiftness of human living. A glacier's normal gait in fact moves it but a few inches in a day, averaging about the same as Fire Island, but you may be surprised to know that certain octopus-shaped glaciers in Alaska and elsewhere, after snailing along this way for a mile in a quarter century, periodically (for some little understood reason) go into a gallop or "surge" a hundred times faster, indeed fast enough for the human eye actually to see them go, and a few have kept up this pace (sometimes accompanied by the babbling voice of internal streams) for as long as three years, with a measured glacial speed of fifty feet a day. That works out to two feet per hour, about half an inch a minute or ten times faster than the minute hand on your watch.

  Glaciers are born very quietly whenever and wherever a summer's thaw does not melt all of the previous winter's snow and, if this excess of snowfall continues in succeeding years, obviously the glacier will grow in proportion, its snow steadily compacting with increasing depth and pressure into ice granules that reach the size of golf balls a hundred feet down, as thousands of feathery snowflakes are progressively welded into each spherical cell unit of the rock-hard organism. It is not easy to discover exactly how or why such an apparently rigid mass will flow, but scientists now know that a glacier almost never slides along the surface of the rocks and soil on which it rests because the friction of rough ground greatly exceeds that within the ice itself. The best evidence suggests that, by the time it gets a hundred feet thick, a glacier has begun to creep like a very stiff liquid, its weight by then heavy enough near its bottom to shear its crystals along internal "glide planes" when and where the local ice temperature reaches the "pressure-melting point." This is a point definable as occupying the precise layer of the beginning of melting under such great stability of insulation and pressure that all the interlacing micropockets of water remain just warm enough to keep liquid and all the surrounding molecular lattices of ice stay just cold enough to keep solid at the same time. A recent test tunnel into deep glacial ice in Greenland proved that the ice was frozen hard all the way to the ground - while the glacial creeping or slipping took place in the zone between one and thirty feet above ground. In other cases the creep level seems to have been more than halfway to the top of the ice, yet significantly always deep inside the body of the moving organism.

  This does not mean that glaciers never push against the ground, for their front walls often encounter rises of rock or even mountains, and it is known that in recent millenniums glaciers have literally sculped the face of the earth, scooping out the Great Lakes, pushing moraines into the shapes of Cape Cod and Nantucket, quarrying rocks from the sides and floors of Scandinavian fjords, chiseling the Alps. A glacier bigger than Europe still sprawls over Antarctica, in places more than two miles thick and 200,000 years old, spreading slowly outward in all directions, harboring significant vegetable and animal organisms from viruses to snow fleas to penguins (page 35) and confidently flaunting its maternity every summer by calving icebergs, some of them as big as the state of Delaware and which, after months of groaning and straining, inevitably snap their umbilical bonds and float free to begin a life of their own.

  There have been four major ice ages in the last million years when more than a quarter of Earth's surface was covered with ice, and at least three earlier series of ice ages separated from each other by very long mild periods averaging about 200 million years. One of the most certain behavioral characteristics in the life of each of these important ice ages has been that it consumed so much ocean water in the form of ice that the world sea level dropped by hundreds of feet, swelling the land at the expense of the sea. Minor ice ages understandably have been both more numerous and more irregular, one of the latest occurring around the time when the pyramids of Egypt were built and another in the great days of Babylon and Persia. The first Christian millennium, in contrast, was a relatively balmy period, and the Norse colonies in Greenland early in the second Christian millennium were helped by a couple of centuries of semi-warmth but ended in a new cool wave and a glacial expansion that increased intermittently right into the nineteenth century. The first half of the twentieth century was distinctly warmer again, but now there are increasing signs of coolth, which, some suspect, may be appreciably influenced for the first time by the filtering effect of man's own output of carbon dioxide, smoke and exhaust fumes. Although the life of glaciers is still but dimly understood, it is evident that there is a suggestively animate pumping action to their limblike lobes that alternately advance and retreat over the centuries. Too, they often interact in unpredictable ways with other dynamic superorganisms such as the salubrious avalanche of rock and earth and ice near Cordova, Alaska, that the 1964 earthquake poured down onto three square miles of dwindling Sherman Glacier, insulating it so well that it stopped dying and has been regrowing vigorously ever since.

  RIVERS AND LAKES

  Having considered the life of such solid beings as sand dunes, islands and glaciers, it should be about as easy now to recognize comparable life in the freer, swifter realms of liquid bodies like rivers and lakes (which are often the descendants of glaciers) as well as vaporous ones like clouds, flames and even whole atmospheres. Rivers, it may be argued, have spines. Like stemmed plants and other vertebrates, they are born, drink, eat and grow. They are inclined to get fat and rich when times are good but, during a famine or a drought, can as easily become thin, take sick and die. Increasingly often they are poisoned (mostly by man) but, when man cares enough (as he has barely begun to do), they are being cured by depollution treatment.

  I hope I'm not carrying the analogy too far when I say that, while most rivers are single, a surprising minority (usually the younger ones) manage to join another of their kind (suitably proportioned) in marriage. On a few occasions what one might call bigamy, and even polygamy, has been observed among them. And although most "married" rivers settle down to a reasonably congenial life, certain ones eventually develop contrary inclinations and separate in divorce. Even widowed rivers are not unheard of. Naturally there are innumerable brooks adolescing all over the wooded parts of the earth, a few of which (unduly stimulated by cloudbursts) literally run wild and might justifiably be classed as juvenile delinquents. Geologists describe one type of headstrong young torrent as "braided streams" because they characteristically rush forward in nearly parallel channels that keep intertwining like braids. Some pirate rivers also "capture" smaller ones and have been known to "behead" them when they stood in the way, which, for all I know, just might explain how the word "rivalry" derived from the Latin rivus, a stream. It is interesting that such happenings would normally be forgotten were it not for the rivers' time-honored custom of writing their own histories in a cursive script that can be read without special training when you fly high over them

  and look down upon the autobiographical "oxbow" lakes, discarded gullies, defunct sandbars and other signatures of abandoned channel beds which once were the aortas of busy mainstream life.

  Rivers really aren't so different from many other life forms when you
consider that they persist in evolving their own distinctive ways of living and moving about, one of the most rivery of traits being their tendency to flow in regular curves called meanders, a word derived from the proverbial winding stream in ancient Phrygia known to the Greeks as the Maiandros. This sinuous figuration, curiously enough, has recently been found by physicists to be neither random nor accidental but rather "the form in which a river does the least work in turning," suggesting that a river's most probable shape is delineated basically by nothing more mysterious than laziness. There is striking evidence, in fact, that meandering is not a phenomenon of rivers or liquids alone, a classic example being the wreck of a Southern Railway freight train near Greenville, South Carolina, on May 31, 1965. Several dozen track rails 700 feet long happened to be riding the train clamped together in one continuous bundle resting upon thirty flatcars, and when the train, pulled by five locomotives, was derailed at full speed

  to pile up against an embankment, the longitudinal compressive strain neatly folded the solid steel bundle into an exquisite model of a lazy Maiandros.

  River meandering is clearly billions of times more leisurely than this, often starting in the straight reach of a callow valley stream with irregular shallows and deeps (known to trout fishermen as riffles and pools) that tend to develop alternately on either side of the channel at intervals of about six times its width, prompted increasingly, as the stream grows, by the observed fact that molecules of water, clay, silt, etc., in a river naturally follow spiral paths downstream, reciprocating from clockwise to counterclockwise to clockwise again with the shifting, shuttling meanders. Over the centuries and milienniums this simple oscillatory proclivity molds all rivers inhabiting flat, soft lands into progressively snakelike contours and, when there is time enough, eventually the volutions outdo themselves, even to rubbing against each other so hard they fuse and short-circuit into new and shorter channels. One could say that rivers in general act a little like wild drivers who go around curves too fast, always swerving to the outside so they scour away material from there and deposit it upon the calmer insides of bends farther downstream. The rate at which this happens is found to be proportional to the slope of the land (therefore to the speed of flow), and, in at least some cases, to the amount of sediment carried in suspension. But there are still so many mysteries in hydraulics, magneto-hydrodynamics and other of the fluid sciences that no one can reasonably claim to fully understand what's going on in a river.