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HOW I STOPPED WORRYING AND LEARNED TO LOVE CONTINGENCY V: CANALIZATION

Part IV

In genetics, canalization is the ability of a genotype to produce the same phenotype regardless of the environmental setting. In an evolutionary context, canalization (often spelled canalisation) is a manifestation of historical contingency. Once a successful genotype arises it tends to persist, and other evolutionary pathways are closed off. The evolutionary trajectory is in some senses confined to a "channel," the metaphor that produced the term canalization. The term, originally due to biologist C.H. Waddington, has since been used by others in a broader sense to refer to historical development phenomena whereby once a particular path is "chosen" there is an element of lock-in (the quotes are not only because Earth surface systems (ESS) lack intentionality, but also because the selection may be due to random chance or be highly sensitive to minuscule variations).

HOW I STOPPED WORRYING AND LEARNED TO LOVE CONTINGENCY IV: INFINITE CONSTRAINTS

Part I              Part II             Part III

2 + 2 = 4.

That is non-contingent. Adding two and two gives the same result no matter who does it, how they do it, where they do it, or when. The same goes for expressions such as 2 + X = 4, or 27/X = 4, etc.

This four-play is a metaphor for the deterministic, Laplacian, non-contingent ideal of science, where the right tools and sufficient information always give the same, correct result under any circumstances.

But a better metaphor for the actual practice of geosciences and other historical, field-based sciences, is that you find, or observe (evidence of) a four. Mathematically, of course, there are an infinite number of numerical operations that could produce a four. Even if you know that the four arose from, say, subtraction or exponentiation, the possibilities are still infinite.

HOW I STOPPED WORRYING AND LEARNED TO LOVE CONTINGENCY III: PERFECTION

The “perfect storm” metaphor describes the improbable coincidence of several different forces or factors to produce an unusual outcome. The perfect landscape refers to the result of the combined, interacting effects of multiple environmental controls and forcings to produce an outcome that is highly improbable, in the sense of the likelihood of duplication at any other place or time (Phillips, 2007a). Geomorphic and other Earth surface systems (ESS) have multiple environmental controls and forcings, and multiple degrees of freedom in responding to them. This alone allows for many possible landscapes and system states. Further, some controls are contingent, and these contingencies are specific to time and place. Dynamical instability in many ESS creates and enhances some of this contingency by causing the effects of minor initial variations and small disturbances to persist and grow over time. The joint probability of any particular set of global controls (laws or non-contingent generalizations) is low, as the individual probabilities are <1. The probability of any set of local, contingent controls is even lower.

HOW I STOPPED WORRYING AND LEARNED TO LOVE CONTINGENCY II: NONLINEAR DYNAMICS & CHAOS

Part I

My first, and abiding, interest in complex nonlinear dynamics arose in an effort to explain the extensive spatial variability in geomorphic and pedologic phenomena often found within short distances and small areas, in the absence of measurable variations in explanatory factors. Dynamical instability and chaos, whereby minor variations in initial conditions or effects of small, local disturbances become exaggerated over time, can explain this phenomenon. We have had considerable success over the past 25 or 30 years in this regard.

Soil profiles exposed on the Neuse River estuary shoreline, Croatan, N.C. Complex local spatial variability--despite uniform parent material--is evident. Dynamical instability and chaos in pedogenesis of the these soils was demonstrated nearly 25 years ago.

HOW I STOPPED WORRYING AND LEARNED TO LOVE CONTINGENCY

Evolution (I use the word here in its most general sense of long term historical development) of Earth surface systems is historically contingent and path dependent. This seems to be true of evolution of anything, but I will stick here to my supposed areas of expertise. The state of an Earth surface system (ESS; a landscape, ecosystem, etc.) is a function of generally applicable laws that ultimately determine the range of possibilities, geographically specific place factors (environmental constraints and opportunities), and history. While laws are general, if not universal, and apply to every ESS of a given type (e.g., stream channel, cave, mangrove swamp, soil profile, etc.), the place factors define the template in which those laws operate.

And then there is history.

SOIL COMPLEXITY & PEDOGENESIS

The editor of Soil Science, Daniel Gimenez, known for his work on complex nonlinear dynamics and fractals in soils, recently suggested that I write a review paper for the journal updating my ideas on complexity in pedology and pedogenesis. It was an interesting challenge that had not otherwise occurred to me, and I'm glad I did it. The result was recently published as:

Phillips, J.D., 2017. Soil complexity and pedogenesis. Soil Science 182: 117-127 (or full text version here).

The abstract is below:

THE NITROGEN BOMB

I just finished reading Paul Bogard's The Ground Beneath Us, (I recommend it), which among other things warns us yet again about the serious issues--environmental, economic, public health, food security--associated with over-reliance on chemical and fossil-fuel intensive industrial agriculture. It's a good 40-years-later follow-up to Wendell Berry's classic Unsettling of America: Culture and Agriculture (Sierra Club Books, 1977).

It also reminded me of a much more technical and difficult book I read a few years back, Jozef Visser's Down to Earth, subtitled "A Historical and Sociological Analysis of the Rise of 'Industrial' Agriculture and the Prospects for the Re-rooting of Agriculture in the Local Farmer and Ecology. Visser, who has graduate degrees in chemistry and a long career in agricultural chemistry, returned to graduate school later in life to produce this book, which is his dissertation from the University of Waginengen (Netherlands). A pdf is available free at the link above, and I recommend it.

LAPLACE'S ANGEL

Back in 1814, Pierre-Simon Laplace published a classic statement on causal determinism in science. If someone (a hypothetical or metaphorical demon, though Laplace's Demon is apparently a later embellishment; Laplace himself did not use the term) has perfect knowledge of the exact location and momentum of every atom in the universe, their future (and past) values at any time can be perfectly determined from classical mechanics.

BIOGEOMORPHIC NICHE CONSTRUCTION BY UPROOTING

Tree uprooting in forests has all sorts of ecological, pedological, and geomorphological impacts. Those are not just related to disturbance--because of the time it takes uprooted trees to decompose, and the distinctive pit-mound topography created, those impacts may last decades to centuries (and sometimes even longer).  One discussion I've often had with colleagues who study this sort of thing has to do with ecosystem engineering and niche construction. Obviously uprooting is a major biogeomorphic process. Obviously it has important impacts on habitat. But do these impacts favor either the engineer species (i.e., the tipped over tree) or some species? Or are they more or less neutral, in the sense of modifying habitat but not necessarily in such a way as to systematically favor any given species?

Uprooted Norway spruce.

STAGES OF BIOGEOMORPHIC EFFECTS

The biogeomorphic impacts of organisms may differ at different stages in the development of landforms, ecosystems, or the individual organisms. I was thinking about this recently here along the shoreline bluffs of the Neuse River estuary, North Carolina, where I have been both looking at some soil profiles and enjoying the coastline.

There are at least five distinctly different biogeomorphic roles trees play along this shoreline--many more if you wanted to get more specific within these categories. The specifics are probably of only limited applicability elsewhere, but the general principle--multiple effects, which vary at different stages of both landform and vegetation development--is widely valid.

Trees and other vegetation grow thick and fast in this moist subtropical climate.

Stage 1A Surface Bioprotection

Trees (including canopy, roots, and litter) protect the ground surface from erosion and add organic matter to soil.

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