VIII
Preface
nized as significant components of the pelagic nutrient budget. This means
that the nutrient household of lakes cannot be considered independently of
the trophic structure of the pelagic community, and also that pelagic
foodweb structure is closely connected with nutrient supply.
Another key idea developed under the Eutrophication Programme was
that nutrient regeneration is an elementary mass balance governed by the
differences in element compositions between the grazer and the food it
consumes. Although this mass balance approach was introduced and
developed in several practically oriented publications (Olsen and 0stgaard
1985; Olsen et al. 1986b; Andersen and Hessen 1991), it was felt that there
was also an important theoretical potential of this simple and powerful
concept. This book has grown out of the difficulties encountered with
trying to fully release this potential within the space constraints of scientific
journals.
While this book is written in terms of the antiseptic differential equations
of theoretical ecology, it is still hoped that it may strike a balance so that it
may serve a dual purpose of introducing some of the powerful techniques
of mathematical biology to the field ecologist, and some of the contemporary problems in aquatic ecology to the theorist. Although simple models
are emphasized throughout this work, some readers might still find the
notation to be quite complex at times. As a help and reference to the
reader, every chapter therefore contains a list of all symbols used in the
presentation, together with definitions and relevant units. Some of the
arguments used in this work are based on concepts that might be unfamiliar to the less mathematically inclined. In order to make the presentation
more accessible to the general reader, some of the more technical parts
have been placed in separate appendices that can be omitted in a casual
reading, hopefully without the main ideas being lost.
Many of the ideas presented here resulted from collaborations with
other scientists involved in the Eutrophication Programme. I am especially
grateful for the continual inspiration and encouragement given by my good
friends and coworkers, Dag Hessen, Anne Lyche, Yngvar Olsen and Olav
Vadstein. I would also like to thank Arne Jensen, Eystein Paasche and
Helge Reinertsen for the ways in which they must have influenced the
course of events at times most critical to the completion of this work. Dag
Hessen, Anne Lyche, Yngvar Olsen, Eystein Paasche and Tron Frede
Thingstad, as well as the series editor, Ulrich Sommer, kindly provided
constructive criticism and helpful suggestions on earlier drafts.
The writing of this book was supported by scholarships from the University of Oslo, the Royal Norwegian Council for Scientific and Industrial
Research and the Norwegian Research Council. I dedicate it to my wife,
Karin, and our children, Katrine and Tone, who patiently endured the
intrusion into domestic life represented by the writing of this book.
Oslo, January 1997
Tom Andersen
Preface
nized as significant components of the pelagic nutrient budget. This means
that the nutrient household of lakes cannot be considered independently of
the trophic structure of the pelagic community, and also that pelagic
foodweb structure is closely connected with nutrient supply.
Another key idea developed under the Eutrophication Programme was
that nutrient regeneration is an elementary mass balance governed by the
differences in element compositions between the grazer and the food it
consumes. Although this mass balance approach was introduced and
developed in several practically oriented publications (Olsen and 0stgaard
1985; Olsen et al. 1986b; Andersen and Hessen 1991), it was felt that there
was also an important theoretical potential of this simple and powerful
concept. This book has grown out of the difficulties encountered with
trying to fully release this potential within the space constraints of scientific
journals.
While this book is written in terms of the antiseptic differential equations
of theoretical ecology, it is still hoped that it may strike a balance so that it
may serve a dual purpose of introducing some of the powerful techniques
of mathematical biology to the field ecologist, and some of the contemporary problems in aquatic ecology to the theorist. Although simple models
are emphasized throughout this work, some readers might still find the
notation to be quite complex at times. As a help and reference to the
reader, every chapter therefore contains a list of all symbols used in the
presentation, together with definitions and relevant units. Some of the
arguments used in this work are based on concepts that might be unfamiliar to the less mathematically inclined. In order to make the presentation
more accessible to the general reader, some of the more technical parts
have been placed in separate appendices that can be omitted in a casual
reading, hopefully without the main ideas being lost.
Many of the ideas presented here resulted from collaborations with
other scientists involved in the Eutrophication Programme. I am especially
grateful for the continual inspiration and encouragement given by my good
friends and coworkers, Dag Hessen, Anne Lyche, Yngvar Olsen and Olav
Vadstein. I would also like to thank Arne Jensen, Eystein Paasche and
Helge Reinertsen for the ways in which they must have influenced the
course of events at times most critical to the completion of this work. Dag
Hessen, Anne Lyche, Yngvar Olsen, Eystein Paasche and Tron Frede
Thingstad, as well as the series editor, Ulrich Sommer, kindly provided
constructive criticism and helpful suggestions on earlier drafts.
The writing of this book was supported by scholarships from the University of Oslo, the Royal Norwegian Council for Scientific and Industrial
Research and the Norwegian Research Council. I dedicate it to my wife,
Karin, and our children, Katrine and Tone, who patiently endured the
intrusion into domestic life represented by the writing of this book.
Oslo, January 1997
Tom Andersen