Book contents
- Frontmatter
- Contents
- List of Boxes
- Preface
- Prologue Environmental changes and ecosystem effects: two historical examples
- Section I History and concepts
- Chapter 1 History of ecology
- Chapter 2 Ecology, ecosystem and ecosystem science
- Chapter 3 Ecosystem ecology: cornerstones and scientific methodology
- Section II Ecosystem structure and function
- Section III Ecosystem dynamics at different time scales
- Section IV Applications
- Appendix 1 Abbreviations
- Appendix 2 Glossary
- Appendix 3 Some useful values and symbols used to represent them
- Appendix 4 Information and data on selected ecosystems
- References
- Index
- Plate section
- References
Chapter 3 - Ecosystem ecology: cornerstones and scientific methodology
from Section I - History and concepts
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- List of Boxes
- Preface
- Prologue Environmental changes and ecosystem effects: two historical examples
- Section I History and concepts
- Chapter 1 History of ecology
- Chapter 2 Ecology, ecosystem and ecosystem science
- Chapter 3 Ecosystem ecology: cornerstones and scientific methodology
- Section II Ecosystem structure and function
- Section III Ecosystem dynamics at different time scales
- Section IV Applications
- Appendix 1 Abbreviations
- Appendix 2 Glossary
- Appendix 3 Some useful values and symbols used to represent them
- Appendix 4 Information and data on selected ecosystems
- References
- Index
- Plate section
- References
Summary
Ecosystem ecology is to a great extent about mass balances of elements and their interactions. The fluxes of elements are strongly coupled to each other, and often one limiting element regulates the fluxes of the others. This chapter gives an introduction to the most important elements and to some key concepts or cornerstones: mass balance, limiting nutrients, optimality and steady state.
A note on terminology
When we talk about ecosystems we need to define the quantities of which they are made. We will refer to concrete, measured or calculated quantities, as stocks of elements. When we talk about these quantities in more abstract terms we use the terms pools or compartments. The movements of matter between pools will interchangeably be called flows or fluxes. The transfer of energy between compartments was previously a key study area in ecology. Today we stress movements of individual elements, in particular carbon, as this approach provides insights into more aspects of ecosystems functionality. Amounts of elements can be expressed either by mass or by number of moles. We will follow the convention in terrestrial ecosystem ecology and use mass units, unless otherwise stated, rather than the molar units that are common in aquatic ecology. The typical units are kg m−2 and Mg ha−1 (1 kg m−2 = 10 Mg ha−1) for stocks, and flows are per year or per day. Mass can also be expressed as dry weight (dw), when all water has been removed, or fresh weight (fw), when the sample is at its ambient water content. Dry weight is often replaced by its carbon content; if no measurements are available a carbon content of 50% can be assumed.
Understanding processes
- Type
- Chapter
- Information
- Terrestrial Ecosystem EcologyPrinciples and Applications, pp. 25 - 38Publisher: Cambridge University PressPrint publication year: 2011