Human activity is affecting the global environment in a profound way. Some of these changes are due to high rates of additions of materials to the environment. Other changes result from losses of habitat and the associated extinctions of species. Many of these human interventions now occur on a scale capable of changing the global biogeochemical cycles upon which life and the Earth’s climate depend.
Biogeochemical cycles describe the transformation and movement of chemical substances in a global context. This text is designed for courses intended to present an integrated perspective on biogeochemical cycles. Courses focusing on this subject are offered at advanced undergraduate and graduate levels in many colleges and universities. These courses are usually presented by a person with a specialty in one of the conventional scientific disciplines, supplemented by guest lecturers and readings in other areas. Our goal has been to provide a comprehensive treatment under one cover so that the components are integrated and the need for additional reading is reduced.
The text has its roots in courses on biogeochemical cycles offered at the University of Washington and at the University of Stockholm. The course at the University of Washington was started by two of the authors (Charlson and Murray), and an essential part of the course has been visits by faculty from other disciplines. Many of the chapters in this text spring from materials prepared for those presentations. Some of the authors are former students in this course.
Much of the work important to the study of biogeochemical cycles is done in traditional disciplines – ranging from astronomy to zoology. Many disciplines that have developed fairly recently (such as chemical oceanography) also play very important roles. This is likely to continue to be the case. Nonetheless, given the nature of biogeochemistry, specialists need to understand what their disciplines can bring to the subject and what are the needs of the other disciplines. To fully comprehend these cycles, a person must also integrate material from several disciplines.
Although our goal has been to be comprehensive, adjustments have had to be made. In managing the compromise between depth of coverage and maintaining a reasonable size for a textbook, many topics are given only limited space. We hope that readers will nevertheless gain an appreciation of the scope of biogeochemical cycles and will be adequately prepared to understand the growing literature in the field.
This book is about fundamental aspects of the science of biogeochemistry. As such, and while it is relevant to the major issues of global change, it is not issue oriented. Not does this book attempt to review all of the research on these topics. It does, however, emphasize fundamental aspects of the physical, chemical, biological, and Earth sciences that are of lasting importance for integrative studies of the Earth.
We assume that our readers have a background in science attainable by completing a university level course in introductory chemistry. We also expect our readers to be involved in one of the disciplines integral to the study of biogeochemical cycles. This includes appropriate subdisciplines of chemistry, biology, and geology, and the sciences that deal with soils, atmospheres, and oceans.
Bert Bolin’s visit to the University of Washington in 1976 provided a major stimulus for thinking about biogeochemical cycles at the university. Active work on this text began with a grant from the Rockefeller Foundation to the Institute for Environmental Studies at the University of Washington in 1978. Rockefeller assistance made it possible to bring several scientists to the University of Washington to discuss the role of their specialty in biogeochemical cycles. Visits from M. Alexander, P. L. Brezonik, P. J. Crutzen, R. A. Duce, R. O. Hallberg, H. D. Holland, M. L. Jackson, G. E. Likens, F. T. Mackenzie, S. Odén, H. Rodhe, and H. J. Simpson played important roles in shaping our approach to the text.
Several individuals played important roles during the final preparation of the manuscript. Most of the typing was done by Sheila Parker. Drafting of figures was done by Kay Dewar and April Ryan. Last but not least, we owe thanks to the many students at the University of Washington and the University of Stockholm who explored this subject initially without a textbook and then with draft chapters. Their enthusiasm for the subject and their comments and criticism have helped maintain our interest in this manuscript over almost a decade.