B. The Nitrogen Sermon (the second in a continuing series on the constituents of the atmosphere)

It's an understandable part of our evolutionary legacy. We have a special bias toward oxygen, that highly reactive gas that it is the indispensable fuel for so many of Earth's organisms. But as unusual as our planet is for having such a high level of free O2 -- currently it is about 21 percent by volume -- the fact remains that it is not the predominant constituent of our atmosphere. Nitrogen, a much different sort of substance, is much more abundant, accounting for approximately 78 percent. In common with oxygen, it has a strong preference to form two-atom molecules (hence its annotation as N2), but unlike its hyperactive neighbor on the periodic table it is pathologically antisocial. It takes a good deal of energy or cleverness, or both, to get this otherwise inert substance to form compounds with other elements.

It is no doubt a very good thing that so much of our planet's atmosphere is inert, and that it freely passes in and out of or lungs without doing anything constructive or destructive. As noted in the previous newsletter, a higher percentage of oxygen would (and has, at other points in geologic time) resulted in a much more flammable world. It's fun to speculate how life would adapt to a new surge in O2: would more of the land be given over to fire-tolerant grasses and forbs? Would insects and other invertebrates develop new, giant forms reminiscent of those that inhabited the oxygen-rich coal swamps of the Pennsylvanian Period, 300 million years ago? As it is, we "higher" organisms, who possess a much more efficient apparatus for bringing large amounts of oxygen into our interiors, find the magic level of 21 percent just perfect.

Ray Wiggers'

Natural History Newsletter

- June 2004 Edition -

Dear Friends,

Once again, I'm honored to say that the subscription list for this newsletter continues to grow rapidly. Whether you're a new subscriber or someone accustomed to my old way of doing things, I hope you'll find this newsletter's new format -- posted as a page on my website rather than sent directly to you as a rather slow-loading E-mail -- easier to read and enjoy. Please let me know what you think.

Those of you who are primarily interested in news of upcoming tours, courses, and lectures may wish to scroll down to Part II immediately. Latest book recommendations are contained in Part III.

PART I. NONLINEAR SOLILOQUIES & SERMONS

C.  The Globs of Spring

The Baraboo Hills of Wisconsin, which I first visited as a Purdue undergrad three decades ago, has been my spiritual Ground Zero ever since. While I hope my understanding of the geology and botany of the region has continued to improve all these intervening years, there is no way in which I could intensify the numinous sense the area gave me when I first went there. That ring of hills, once an archipelago in the shallow equatorial sea of 500 million years ago, speaks to me of endurance and multilayered meaning on an redeemingly inhuman scale -- and of the interplay of continuity and change in a vast ocean of time.

PART II. UPCOMING EVENTS

A. Tours

Newly listed summer and fall 2004 natural-history trips offered by me personally are now listed, predictably enough, on this website's Tours Page. Among the offerings are the ever-popular Fossil Finders trips to the Mazon Creek area, guided park visits in northeastern Illinois and southwestern Michigan, and a trip this October to Wisconsin's Baraboo Hills and the Driftless Section.

PART III. RECOMMENDED BOOKS

Geology

Volcanoes are to geology what dinosaurs are to paleontology -- a perennial favorite with the greater public, and thus a "gateway subject" that can lead the curious layperson to other aspects of these sciences. While there are many beautiful (and educational) full-color picture books on the subject of vulcanology, the geologist or aspiring naturalist who wants to go considerably deeper into the subject should consult what I consider one of the classics of specialty earth-sci textbooks: Volcanoes, 2nd edition, by Peter Francis and Clive Oppenheimer (Oxford University Press, ISBN 0199254699). The senior author, who died recently, was responsible for turning what could have been a very dry account in the distant and awkward style of most professional scientists into a well-written delight to read. The text crackles with personal observations and sidelong references to social conventions, music and the other arts, and the squabbles of academicians.

PART IV. THIS ISSUE'S PARTING QUOTATIONS

This advertisement, which the great explorer Sir Ernest Shackleton placed in British newspapers when he was assembling his crew for his Transantarctic Expedition, is a masterpiece of reverse psychology and focused force through brevity:

Men Wanted for Hazardous Journey

Small Wages

Bitter Cold

Long Months of Complete Darkness

Constant Danger

Safe Return Doubtful

Honour and Recognition in Case of Success

- Ernest Shackleton

Not surprisingly, Shackleton was swamped with applicants. Later, after his expedition had failed to achieve its original purpose -- after his ship had been crushed into kindling by the pack ice -- both leader and crew had to contend with extreme hardship and a sense of hopelessness that few of us could now imagine. Nevertheless, Shackleton led his men to a safe if barren haven on a small, icebound island in the Antarctic Ocean. Then, with a few handpicked companions, he made an open-boat voyage across that stormy sea. It was one of the greatest feats of seamanship of all time. After making landfall at South Georgia -- the right island, but the wrong side of it -- he traversed on foot a range of mountains, crevasse-ridden glaciers, and a bonechilling waterfall to reach the island's one permanent settlement. In the end, his higher mission, to rescue the crew he'd left behind without the loss of a single life, was granted him. Of this most intense suffering and effort he wrote:

A. Quick Takes on Earth History, Part One: The World's Worst Day

When I teach historical geology, as I am doing now in summer session at Lake Forest College, I remind my students more than once that the long chronicle of our planet is a combination of profound but gradual processes -- the dripping of water on stone, the patient carving of rock by wind, the inch-by-inch creep of continents -- and the much rarer but overtly dramatic events we call catastrophes. Of the latter group, nothing matches the event that many earth scientists now infer from various lines of evidence -- an event that almost destroyed our planet just a few hundred million years after the Earth's formation.

This earliest eon of Earth history, evocatively named the Hadean, was an insufferably hot and vicious time by human standards. During this span, from about 4.6 to 3.8 billion years ago, our planet's basic physical and chemical characteristics were forged, but in a setting radically different than that of the Earth today.  The crust, heated from below by the decay of a superabundance of radioactive material and from above by a stiff bombardment of debris in what was still a dirty and disheveled solar system, was still largely molten. There were no continents and no ocean basins in the modern sense.

It was in this context that Earth suffered the worst day in its entire history. According to latter-day theory, our planet was struck by another, Mars-sized world approximately 4.4 billion years ago. The blow must have been a glancing one; a direct hit was have destroyed the larger Earth as well. But as it was, the impact enough to break apart the smaller body, which added its metallic core to the Earth's own and sent much of its mantle into a debris field orbiting the Earth. Eventually the pulverized remains of this alien world coalesced to form the Moon.

Little direct geologic evidence has survived from the Hadean Eon, so this startling hypothesis about the Moon's origin remains just that -- a hypothesis. However, the theory does explain some puzzling things about the Earth and its orbiting companion -- why, for example, the Moon's mineral composition (as revealed in rocks collected by Apollo astronauts) is so different from Earth's, and why the Earth spins on its axis as rapidly as it does.

However, this is not to suggest that nitrogen performs its most crucial role by doing nothing more than being a sort of atmospheric filler. Indeed, the interaction of atmospheric nitrogen and the land and water beneath it is one of the most fascinating aspects of natural history. If you are a gardener, if you are are restorer of native habitats, or if you are simply interested in your own nutrition and having the one trillion cells in your body continue to build and use the protein molecules they so desperately need, take heed. Were nitrogen not forcibly combined to other atoms by the ceaseless efforts of countless microorganisms in the soil and the sea, we would all quite readily starve or, perhaps, fall apart.

These day, biologists and geologists spend a lot of time talking about the Earth's various cycles: the Water Cycle, the Carbon Cycle, and so forth. The key concept here is that this world is in many ways a closed system in which its vital constituents circulate from one environment to the next without ever being destroyed: the water you drink today was sipped by some dinosaur 200 million years before, and the carbon currently locked away in a limestone outcrop in southern Illinois once worked instead as a greenhouse gas. Nitrogen has its cycle, too, and it is of special significance to those who work the soil or have reason appreciate its inhabitants.

As every gardener quickly learns, nitrogen is at the top of the list of macronutrients -- the elements that are needed in relatively large amounts for the proper growth and functioning of the stems, roots, and other plant parts. However, the path taken by nitrogen atoms from their unusable elemental form (N2) to the compounds plant cells can use is a remarkably involved one, and involves a complex if microscopic ecosystem that is the foundation for so many others.  First, atmospheric N2 present in the pore spaces between soil particles is "fixed" by certain bacteria that have developed the ability to do what so many other organisms find impossible -- to combine the N2 with hydrogen to produce ammonia (NH3). This compound is quickly employed by many living organisms to construct proteins. However, when these organisms eventually die, their residual organic matter is incorporated into the soil, and an elegant chain of events, based on the much maligned but crucial process of decay, takes place. This process is called nitrification. Rotting produces ammonium (NH4), and the ammonium is then attacked by some bacteria, which produce nitrite (NO2). In turn, the nitrite is converted by other bacteria into nitrate (NO3). And it is the last-named form that is the optimal source of nitrogen for plants.

Of course, the Nitrogen Cycle would not close in on itself, as all cycles must, unless there were still other microorganisms that cause denitrification. These microbes return nitrogen to its N2 phase by breaking down nitrates, nitrite, and ammonium, in a step-by-step reversal of the process cited above.

Depending on the time of year, they can look like offbeat, horned Christmas ornaments designed by an eccentric aunt who never left the 1970s, or like gelatinous globs of the worst grade-school pudding you'll ever encounter in your nightmares.

Here at Parfrey's Glen, they were definitely in the nightmare-pudding phase of their existence. These globs were the spore-producing structures of a fungus -- the cedar-apple rust (Gymnosporangium juniperi-virginianae). This interesting if troublesome parasite is much more familiar to orchardists and homeowners as a malady of cultivated apple and crabapple trees, where it forms yellow spots on the leaves and fruit. 

As complicated as the cedar-apple rust's life cycle seems -- in that one generation must find one type of of tree, and the next generation must find a quite different sort of tree -- this species is by no means the only example of this sort of complicated and polymorphic approach to life. In Colonial times, New England wheat growers were plagued by Puccinia graminis, the dreaded wheat stem rust. When it was discovered that its alternate host was the imported barberry shrub, the latter was outlawed and extirpated wherever it was found growing.

As ancient as it it is, this glacially polished outcrop of 2.7-billion-year-old BIF (Banded Iron Formation) in Tower, Minnesota postdates the end of the Hadean Eon by almost a full billion years. No Hadean rock outcrops are known to survive; however, some grains of the virtually indestructible mineral zircon found in Australia have been isotopically dated to about 4.1 billion years. (Photo by Raymond Wiggers.)

In a church cemetery in Baptist Hill, South Carolina. The afternoon sunlight filters through the branches of a live oak (Quercus virginiana) and the long tufts of Spanish moss (Tillandsia usneoides) that hang from them. These highly advanced flowering plants, so different in their forms, get their crucial supply of nitrogen compounds in different ways: the oak, mainly from the action of nitrifying soil bacteria, and the Spanish moss from substances already dissolved in rainwater. (Photo by Raymond Wiggers.)

Two views of the red-cedar phase of cedar-apple rust, at Parfrey's Glen, Wisconsin. The spore-producing, horned projections, especially visible in the righthand photo, are called telia.

(Photos by Raymond Wiggers.)

B. Courses

As many of you have heard, I have ended my five-year association with the School of the Chicago Botanic Garden to my devote my efforts to such well-run programs as those presented by the Chicago Architecture Foundation and the Lake Forest Open Lands Association. For the latter organization, I will be teaching a new course this fall that explores  the geology, botany, and plant ecology of three of LFOL's most popular and scenic properties. This course -- for which you may enroll for single classes or the whole set of three -- will be held on Friday mornings in September, October, and November. Please note that this course is not just open to Lake Forest residents! It will also be of great interest and educational value to anyone interested in learning more about Illinois' geologic origins, plant communities, and native plant species. For more information, click here.

C. Lectures

My public-lecture schedule has just been updated and now lists summer and fall 2004 appearances in such locales as Racine, Wisconsin and Will County and Lake Zurich, Illinois.

The magnificent, original-growth American beech (Fagus grandidentata) and sugar maple (Acer saccharum) forest at Warren Woods in southwesternmost Michigan will be the subject of a Mini-Trek hike this coming Sunday 29 August. (Photo by Raymond Wiggers.)

We had pierced the veneer of outside things. . . . We had seen God in his splendors, heard the text that Nature renders. We had reached the naked soul of man.

It is very hard to pierce the veneer of outside things. And when it happens, as everyone of sufficient age and experience knows, it is most likely the unexpected result of profound grief.

Have a good summer exploring,

Ray Wiggers

This year I've had special need to be in that sacred place. During one of recent trips there, I made it a point to visit Parfrey's Glen, the small but magnificent canyon cut into the purple Cambrian conglomerate that flanks the core of ancient quartzite hills, just after sunrise. As I'd hoped, the rush hour of hiker-naturalists had not yet begun. It was one of those soggy, below-the-dewpoint days, with puffs of fog drifting among the red cedars near the site entrance.  Normally, I would have marched by those trees without offering them much scrutiny, but on this occasion I happened to note they were festooned with the same arrestingly orange objects I described a decade ago in my Plant Explorer's Guide to New England. Of these objects I wrote,

The upper reaches of Parfrey's Glen -- which will be one of the attractions on my Baraboo natural-history tour this fall (see the Tours Page). The canyon's small stream has carved its way through Cambrian-Period boulder conglomerate, some of which was deposited during tropical storms half a billion years ago. (Photo by Raymond Wiggers.)