Towards a Thermodynamic Theory for Ecological Systems

S.E. Jorgensen, Y.M. Svirezhev

• Publisher: Pergamon
• Year: 2004
• ISBN:
  9780080471747
• Topic: Biological Sciences
• Subtopic: Environmental Science
• Index: Biological Sciences

The book presents a consistent and complete ecosystem theory based on thermodynamic concepts. The first chapters are devoted to an interpretation of the first and second law of thermodynamics in ecosystem context. Then Prigogine's use of far from equilibrium thermodynamic is used on ecosystems to explain their reactions to perturbations. The introduction of the concept exergy makes it possible to give a more profound and comprehensive explanation of the ecosystem's reactions and growth-patterns. A tentative fourth law of thermodynamic is formulated and applied to facilitate these explanations. The trophic chain, the global energy and radiation balance and pattern and the reactions of ecological networks are all explained by the use of exergy. Finally, it is discussed how the presented theory can be applied more widely to explain ecological observations and rules, to assess ecosystem health and to develop ecological models.

Chapter 1

Thermodynamics as a method: a problem of statistical description

Publisher Summary

This chapter discusses the present ecosystem theory to build a theoretical network in ecology and shows to what extent such a theoretical network has been established. The advantages of having an ecosystem theory allow a better understanding of the nature, including the behavior of ecosystems and their reactions to different perturbations. An ecosystem theory is also applicable in environmental management, because it allows predicting how ecosystems react to various sets of man-controlled forcing functions. The thermodynamic interpretation of an ecosystem theory by use of the concept of exergy is the main focus of the chapter. Exergy may be applied as a core concept in a thermodynamic edition of an ecosystem theory. Various approaches have different advantages in different situations. When an ecosystem problem is best solved by use of an approach based on energy and exergy, these concepts should be applied, but when the processes and reactions concern the network, the use of a network theoretical approach may give clear advantages. The relationship between the different approaches is also mentioned to emphasize the importance of a pluralistic view to describe an ecosystem.

Andiam. Incominciate! Leoncavallo “Pagliacci”

Thermodynamics is full of highly scientific and charming terms and concepts, giving an impression of philosophical and scientific profundity. Entropy, thermal death of the Universe, ergodicity, statistical ensemble—all these words sound very impressive posed in any order. But, placed in the appropriate order, they can help us to find the solution of urgent practical problems. The problem is how to find this order…(from table talks in Copenhagen and Potsdam).

1.1 Literary introduction

In the beginning, thermodynamics was an experimental science, and it was only after the work of Gibbs and Boltzmann that an understanding of the statistical basement of all thermodynamic relations appeared. Nevertheless, it is necessary to note that, despite all these discussions about determinism and randomness, metasystemic properties of large systems and the macroscopic description of ensembles consisting of the large number of “similar” microscopic units that are considered as historical facts today, a full understanding has still not been achieved. This is especially so in relation to sciences that differ from physics and chemistry, such as biology and social sciences, where we also deal with ensembles of many interacting individuals (particles, “molecules”, etc.?), and where the idea of applying thermodynamics formalism is very attractive. But “before to discuss the problem, let us come to an agreement about definitions” (N. Timofeev-Resovsky).

Over many years of one of us delivering a course of lectures under the title “Mathematical biology” at the Moscow State University for mathematicians, the problem arose of the meaning of such terms as statistical ensemble, stochasticity or randomness, stochastic processes, how to pass from microscopic description to macroscopic one, etc.? We should like to avoid a superfluous “bourbakism” in these definitions and descriptions. A lot of different books were examined with an unexpected result. The best description of the nature of randomness, the relation between microscopic and macroscopic variables, and, as a special application, the role of stochasiticity and determinism in human history was given by Leo Tolstoy in his great novel “War and Peace”. Let us cite these pages.

“From the close of the year 1811 intensified arming and concentrating of the forces of Western Europe began, and in 1812 these forces—millions of men, reckoning those transporting and feeding the army—moved from the west eastwards to the Russian frontier, toward which since 1811 Russian forces had been similarly drawn. On the twelfth of June 1812, the forces of Western Europe crossed the Russian frontier and war began, that is, an event took place opposed to human reason and to human nature. Millions of men perpetrated against one another such innumerable crimes, frauds, treacheries, thefts, forgeries, issues of false money, burglaries, incendiarisms, and murders as in whole centuries are not recorded in the annals of all the law courts of the world, but which those who committed them did not at the time regard as being crimes.

What produced this extraordinary occurrence? What were its causes? The historians tell us with naive assurance that its causes were the wrongs inflicted on the Duke of Oldenburg, the non-observance of the Continental System, the ambition of Napoleon, the firmness of Alexander, the mistakes of the diplomatists, and so on.

Consequently, it would only have been necessary for Metternich, Rumyantsev, or Talleyrand, between a levee and an evening party, to have taken proper pains and written a more adroit note, or for Napoleon to have written to Alexander: “My respected Brother, I consent to restore the duchy to the Duke of Oldenburg”—and there would have been no war.

We can understand that the matter seemed like that to contemporaries. It naturally seemed to Napoleon that the war was caused by England’s intrigues (as in fact he said on the island of St. Helena). It naturally seemed to members of the English Parliament that the cause of the war was Napoleon’s ambition; to the Duke of Oldenburg, that the cause of the war was the violence done to him; to businessmen that the cause of the war was the Continental System which was ruining Europe; to the generals and old soldiers that the chief reason for the war was the necessity of giving them employment; to the legitimists of that day that it was the need of re-establishing les bons principes, and to the diplomatists of that time that it all resulted from the fact that the alliance between Russia and Austria in 1809 had not been sufficiently well concealed from Napoleon, and from the awkward wording of Memorandum No. 178. It is natural that these and a countless and infinite quantity of other reasons, the number depending on the endless diversity of points of view, presented themselves to the men of that day; but to us, to posterity who view the thing that happened in all its magnitude and perceive its plain and terrible meaning, these causes seem insufficient. To us it is incomprehensible that millions of Christian men killed and tortured each other either because Napoleon was ambitious or Alexander was firm, or because England’s policy was astute or the Duke of Oldenburg wronged. We cannot grasp what connection such circumstances have with the actual fact of slaughter and violence: why because the Duke was wronged, thousands of men from the other side of Europe killed and ruined the people of Smolensk and Moscow and were killed by them.

To us, their descendants, who are not historians and are not carried away by the process of research and can therefore regard the event with unclouded common sense, an incalculable number of causes present themselves. The deeper we delve in search of these causes the more of them we find; and each separate cause or whole series of causes appears to us equally valid in itself and equally false by its insignificance compared to the magnitude of the events, and by its impotence—apart from the cooperation of all the other coincident causes—to occasion the event. To us, the wish or objection of this or that French corporal to serve a second term appears as much a cause as Napoleon’s refusal to withdraw his troops beyond the Vistula and to restore the duchy of Oldenburg; for had he not wished to serve, and had a second, a third, and a thousandth corporal and private also refused, there would have been so many less men in Napoleon’s army and the war could not have occurred.

If Napoleon had not taken offence at the demand that he should withdraw beyond the Vistula, and not ordered his troops to advance, there would have been no war; but had all his sergeants objected to serving a second term then also there could have been no war. Nor could there have been a war had there been no English intrigues and no Duke of Oldenburg, and had Alexander not felt insulted, and had there not been an autocratic government in Russia, or a Revolution in France and a subsequent dictatorship and Empire, or all the things that produced the French Revolution, and so on. Without each of these causes nothing could have happened. So all these causes—myriads of causes—coincided to bring it about. And so there was no cause for that occurrence, but it had to occur because it had to. Millions of men, renouncing their human feelings and reason, had to go from west to east to slay their fellows, just as some centuries previously hordes of men had come from the east to the west, slaying their fellows.

The actions of Napoleon and Alexander, on whose words the event seemed to hang, were as little voluntary as the actions of any soldier who was drawn into the campaign by lot or by conscription. This could not be otherwise, for in order that the will of Napoleon and Alexander (on whom the event seemed to depend) should be carried out, the concurrence of innumerable circumstances was needed without any one of which the event could not have taken place. It was necessary that millions of men in whose hands lay the real power—the soldiers who fired, or transported provisions and guns—should consent to carry out the will of these weak individuals, and should have been induced to do so by an infinite number of diverse and complex causes.

We are forced to fall back on fatalism as an explanation of irrational events (that is to say, events the reasonableness of which we do not understand). The more we try to explain such events in history reasonably, the more unreasonable and incomprehensible do they become to us.

Each man lives for himself, using his freedom to attain his personal aims, and feels with his whole being that he can now do or abstain from doing this or that action; but as soon as he has done it, that action performed at a certain moment in time becomes irrevocable and belongs to history, in which it has not a free but a predestined significance.

There are two sides to the life of every man, his individual life, which is the more free the more abstract its interests, and his elemental hive life in which he inevitably obeys laws laid down for him.

Man lives consciously for himself, but is an unconscious instrument in the attainment of the historic, universal, aims of humanity. A deed done is irrevocable, and its result coinciding in time with the actions of millions of other men assumes an historic significance. The higher a man stands on the social ladder, the more people he is connected with and the more power he has over others, the more evide...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright page
• Dedication
• Preface
• Chapter 1: Thermodynamics as a method: a problem of statistical description
• Chapter 2: The laws of classical thermodynamics and their application to ecology
• Chapter 3: Second and Third Law of Thermodynamics in open systems
• Chapter 4: Entropy, probability and information
• Chapter 5: Work, exergy and information
• Chapter 6: Stability in mathematics, thermodynamics and ecology
• Chapter 7: Models of ecosystems: Thermodynamic basis and methods. I. Trophic chains
• Chapter 8: Models of ecosystems: thermodynamic basis and methods. II. Competition and trophic level
• Chapter 9: Thermodynamics of ecological networks
• Chapter 10: Thermodynamics of vegetation
• Chapter 11: Thermodynamics of the biosphere
• Chapter 12: Teleology and extreme principles: a tentative Fourth Law of Thermodynamics
• Chapter 13: Application of exergy as ecological indicator and goal function in ecological modelling
• Postscriptum
• References