Beneath the Surface
The World Turned Upside Down
By Farwell Forrest
October 19, 2004
You don't often hear a paddler shouting "Dive!"
to her partner. That's to be expected. Canoeists and kayakers are creatures of
the air, operating along the fluid interface between the
worlds of wind and water. Even the submariners among us seldom venture
deeper than six feet beneath the surface. But that doesn't mean we don't
wonder what lies under our keels, does it? I do. As I paddle across the
wind-rippled surface of an Adirondack lake on a blustery
autumn morning, a kingfisher rattles in the distance, and a yearling buck
drinks warily in the shallows. Nothing else is going on. Or is it? I can't
escape the feeling that something big is happening and that it's
happening somewhere very close. But where? And what going on?
My curiosity about the unknown country beneath the surface of the water
began when I was a boy. Long before I could afford a canoe the boats I built
with orange crates and scrap lumber salvaged from the city dump seldom
lasted long I owned a snorkel, a cheap diving mask, and a pair of
swim-fins. On sultry summer days, I'd grab my fins, hop on my
bike, and ride to a disused reservoir just outside the city limits. There
I'd crawl through a gap in the chain-link fence and spend an hour or two
seeing what I could see.
That usually wasn't much, to be honest. The reservoir was so choked with
silt and algae that I was lucky if I could glimpse my hand in front of my face
once I was underwater. This led to some unpleasant moments, including a
nightmarish encounter with a drowned barbed-wire fence. Not all surprises were
so unwelcome, however. After long weeks of hot, humid weather, the water near
the reservoir's surface was nearly as warm as the air almost too warm
to cool a boy still sweating from a 15-mile bike ride. So I'd swim out beyond
the tepid shallows and then dive as deep as my lungs would let me. Ten feet.
Fifteen feet. Twenty feet. My eardrums protested painfully, but the water was
still as warm as syrup. And then, somewhere between twenty and thirty feet
down, a miracle occurred. In less time than it took me to swim one stroke, the
temperature dropped twenty degrees or more. Now I was swimming in water that
was cold enough to make me shiver. The instant relief from the enervating heat
of an eastern summer was wonderful, and I stayed down as long as could. It
wasn't very long, of course a minute or two at most. That didn't
matter. Each second was delightful. Only when my racing pulse reminded me that
I was an air-breathing mammal would I jackknife my oxygen-starved body around
and head for the surface, back into the heat of the day.
The sudden transition from warm water to cold puzzled me at the time, but I
was content to let it remain a mystery. I didn't think about it again until
many years later, when I was a thirty-year-old student on a limnology field
trip to an Adirondack lake the same lake, as it happens, to which I've
returned today, more than twenty years later still, to watch a deer drinking
and to listen to the rattle of a kingfisher. And just what is
limnology? Simply another name for the systematic study of inland
waters. It's a comparatively new science. The word was coined in the last
years of the nineteenth century by F. A. Forel, a Swiss professor whose
work on Lake Geneva earned him the title "father of limnology." Some would
dispute this. Henry David Thoreau's meticulous record of Walden Pond is
arguably the pioneering text in the field, even if Thoreau didn't feel
the need to elevate his observations to the status of a new science, let alone
publish them in a professional journal. Not that such quibbles are important.
Limnologists were continuing to debate the history and scope of their discipline
in the late 1970s, and for all I know they're at it even now.
In any event, my fellow students and I were blissfully unaware of these
sterile academic squabbles. Away from the confines of the lecture hall at
last, we got ready for our first practical exercise in limnology. And though I
didn't yet know it, I was preparing to revisit the almost-forgotten mystery
from my youth. The experiment didn't go well at first. As a boy, I'd gone
swimming to escape the stultifying heat of the city. Now, as a superannuated
college student, I'd come to limnology for much the same reason: to escape
from the lifeless, stultifying abstractions of economics, if only for a few
hours. This time around, though, my escape attempt nearly failed. The
biologist who taught our class was the sort of tedious time-server who
sometimes settles out in small state colleges, far more interested in his
part-time job as coach of the women's volleyball team than in his classroom
duties. (Only later, when I met the biologist's wife, did I begin to
understand why.) So I and the other students were left largely on our own, to
learn the subject as best we could. We did what we thought best. We headed for
What happened next? I dropped a weighted temperature probe over the side of
the leaky aluminum rowboat that did duty as the college research vessel. Then
I lowered the probe slowly down into the water on a knotted line, watching the
needle on the thermometer and calling out temperatures at
one-meter intervals. My partner in the boat recorded these readings, plotting
a rough graph of temperature against depth on a pad of squared paper. At
first, his hastily-sketched line was nearly vertical. Water temperature was
almost constant. Suddenly, though, the line jogged to the left. In the space
of two meters, water temperature dropped 10 degrees Celsius, nearly 20 degrees
Fahrenheit. That was when I remembered my childhood trips to the reservoir
outside the city. And even though I was sitting in a rowboat on a warm,
late-summer afternoon, I began to shiver.
That evening, I opened my textbook to try to make sense of what we'd seen.
I soon learned that we'd found the thermocline, the interface between
warm surface water and the much colder water of the Adirondack lake's depths.
The sudden transition from warm to cold is characteristic of many lakes in
temperate regions, particularly in summer months. Surface waters are
warmed by the sun, and warm water is less dense than cold. As one hot day
follows another, each a little hotter than the last, the lake slowly
stratifies. The water in the lightless depths retains its winter chill, while
sun-warmed water floats above it. And a sharply-defined transition zone
the thermocline divides the two.
Nor is temperature the only thing to change with depth. The water below the
thermocline is dark as well as cold. No light, no photosynthesis. No
photosynthesis, no oxygen. The result? The lake's deeper waters are both cold
and oxygen-poor. Above the thermocline, all is warmth and light and life.
Below, there is only the chilly stillness of the tomb. This isn't just empty
rhetoric. The inhabitants of the upper, sun-warmed waters, from plankton to
pike, sooner or later suffer the fate of all living things. The newly dead
then sink downward into the chill depths. Once there, they decompose, further
depleting the already diminished oxygen reserves, while at the same time
enriching water and sediment with nutrients derived from their bodies. Over
time, the upper and lower worlds diverge. The upper waters are oxygen-rich but
nutrient-poor. The depths, oxygen-poor but nutrient-rich. The upper world
starves. The lower world suffocates. Yet there is little exchange between the
two. Little, that is, beyond the gentle rain of the dead, augmented by the
waste products of the living. This rain falls steadily from the world of light
into the lower realm, a tomb in fact as well as fancy: dark, still, and silent
and stocked with the treasures of the dead.
Now summer draws to a close. Shorter days and cooler temperatures allow the
water near the surface of the lake to cool, and as it cools, it sinks. The
stable, ordered world of summer warm, light water on top; heavy, cool
water below begins to break down. It's a revolution of sorts, hurried
along by the
brisk northerly winds that drive the first masses of cold air south from
the subarctic. And when autumnal storms kick up big waves on the lakes, deep vertical
eddies form, breaching the thermocline barrier again and again and putting
an end to the surface water's splendid isolation. The fall overturn is under
way. The mixing of waters has begun, and a new chapter in the life of the
northern lakes is about to open.
Overturn. Upheaval. A new order. These words strike a chord with most of us
Americans, don't they? Our national folklore is rich in revolutionary images.
In fact, I've often heard it said that a British marching band played a
melancholy air entitled "The World Turned Upside Down" when Lord Cornwallis
surrendered to General Washington. It's a wonderful tale, to be sure, rich in
dramatic irony. And the defeat of the British army at Yorktown did signal
a revolutionary change in the established order of things, as well as being a
harbinger of even greater upsets to come. But historians a rather sour
lot, on the whole, with little appreciation for a good story insist on
pooh-poohing the whole idea. Few of them would suggest that the scarlet-coated
fifers played a jolly tune, of course. The British had little reason to
celebrate. But no one took enough notice of whatever it was they played to
write it down. It could have been almost anything.
So much for history. A revolution of a very different kind is going on
beneath my boat, even as I paddle out across this choppy Adirondack lake. An
ordered, stable underwater world is experiencing a great, unseen cataclysm.
Two long-separated realms a kingdom of light and warmth and life, on
the one hand, and a chilly tomb, richly endowed with the treasures of the
dead, on the other are now being forced together. Each gives something
up, and each gains by the exchange. The warm water surrenders some of its
oxygen; the cold, some of its treasure of nutrients. A great equalizing has
begun, just in time for the long sleep of winter.
If that doesn't warrant playing "The World Turned Upside Down," I don't
know what does. But let's not score it as a melancholy dirge. A lively tune is
far better suited to the day. This is one revolution that leaves no defeated
enemy in its wake, makes no grieving widows or orphaned children. This
revolution brings new life to northern waters.
And that is something to celebrate.
Copyright © 2004 by Verloren Hoop Productions. All rights