PREFACE

This volume has two first authors because it is a result of very intensive

teamwork between the two authors. We have had three brainstorm meetings,

each of approximately one week’s duration. There have been numerous ping-

pong games (questions–answers–new proposals etc.) on the Internet. All the

chapters have major contributions from both of us. We hope that the volume

therefore demonstrates a synergistic effect, reflecting the positive teamwork

that is behind the volume. The teamwork has been particularly fruitful

because we have different scientific backgrounds, but still have ecological

modelling and thermodynamics as a common platform. Sven Erik Jørgensen

has, in addition to modelling and thermodynamics, a background in

chemistry and biology (mainly system ecology), while Yuri M. Svirezhev is

a passionate mathematician, who has used his mathematics during almost his

entire career on biological–ecological problems. He has been able to present

many of Sven Erik Jørgensen’s previously published ideas with the right

mathematical elegance, but there are also a lot of new ideas that are a result of

the teamwork and the brain storming meetings. In turn, many concepts of

mathematical ecology developed by Yuri Svirezhev are considered in the

book from the new, thermodynamic point of view.

The application of thermodynamics on biological systems far from

thermodynamic equilibrium is not new. It is possible to find numerous

references on this topic in the past with Ostwald’s, Bauer’s and Prigogine’s

contributions as maybe the most important. Over the last three decades, many

new and original contributions have been added to the previous theory, and

we believe that today we have a solid and applicable theory of ecological

systems far from thermodynamic equilibrium that is sufficiently developed to

explain ecological observations (see the final chapter). We have built the

presented theory very much on our own work using exergy as a core

thermodynamic variable. We have, however, also touched on other

approaches presenting the research from the last three decades in system

ecology (for instance, the work of H.T. Odum, B.C. Patten, R. Ulanowicz,

E. Tiezzi and F. Muller). Ecosystems are extremely complex systems, and it is

therefore not surprising that the various approaches are to a large extent

complementary. Presentation of a consistent and comprehensive theory is,however, facilitated by the application of one approach with which you arefamiliar. Therefore, the application of exergy to explain the ecosystemreactions and processes is the core theme. In addition, we believe that aconsistent and comprehensive theory cannot be developed, at least not today,without thermodynamics. We hope, however, whatever background you mayhave as reader of this book, and whatever ecosystem approach you prefer,that you do agree: we have an ecosystem theory and we should use it muchmore widely in ecology. The application of thermodynamics on ecosystemsrequires a heavy use of mathematics; but to emphasise the application of thetheory to understand ecosystems and to explain ecological observations, wehave included an ecosystem theoretical summary in most chapters. We havehere presented the implications of the theory of particular interest in systemecology.Behind the presented theory are many important contributions from other

scientists with whom we have cooperated for a shorter or longer time. Theyhave inspired us by their thoughts, not only the thoughts resulting in jointpublications, but also the many thoughts that have been “hanging in the air”at a brain storming. We would like to express our appreciation to all of them:Vyacheslav Alexeev, Brian Fath, Niels Ladegaard, Joao Marques, HenningMejer, Felix Mu€ller, Søren Nors Nielsen, Bernard C. Patten, VladimirPetukhov, Vicente Santiago, Wolf Steinborn, Alexey Voinov, MaciejZalewski, Nikolai Zavalishin and J. Zhang.We are also grateful to Valentina Krysanova, Valery Pomaz, Alison

Schlums, Stephen Sitch and Anastasia Svirejeva-Hopkins for their help in thepreparation and editing of our manuscript.Finally, we are very grateful to H.-J. Schellnhuber, the Director of the

Potsdam Institute for Climate Impact Research, who has provided Potsdam’splayer in our team with the perfect conditions for working on this book.

Sven Erik Jørgensen and Yuri M. Svirezhev,

Copenhagen and Potsdam, September 2003..

Prefacexiv