Contents
xiii
12 Assessing Ecosystem-Level Water Relations Through Stable Isotope
Ratio Analyses
181
James R. Ehleringer, John Roden, and Todd E. Dawson
Introduction
181
Stable Isotopes: Natural Abundances and 0 Notation
181
Isotope Ratio Mass Spectrometry
181
Meteoric Water Line
183
Evaporative Enrichment
183
Methods for Water Sampling, Extraction, and Analysis
184
Water Sample Collection and Storage
184
Soil, Leaf, and Stem Water Extraction
185
oD Analysis of Water
185
0 18 0 Analysis of Water
186
Methods for Leaf and Stem Organic Matter Sampling, Extraction,
and Analysis
186
Total Tissue Versus Cellulose Analysis
186
Leaf Sampling Considerations
187
Tree Ring Separation and Cellulose Purification
187
o13C Analysis of Organic Matter
188
oD Analysis of Organic Matter
189
0 18 0 Analysis of Organic Matter
189
Short-Term, Ecosystem Process-Level Applications
189
Partitioning of Water Resources Among Plants Within
Ecosystems
189
Using oD and 0 18 0 Water Pulses and Interpretation of Mixing
Models
191
Water-Use Efficiency
192
Short-Term, Regional Process-Level Applications Across
Ecosystems
193
Recycling of Water Among and Between Ecosystems
193
0 18 0 of Atmospheric Carbon Dioxide
193
Long-Term, Temporal Scaling of Ecosystem Processes
193
Decadal-to-Century: Tree Rings
193
Millennial: Caliche
194
Animals
194
Short-Term Indicators of Water Source
194
Long-Term Indicators of Water Source
194
References
195
13 Measuring Water Availability and Uptake in Ecosystem Studies
199
Robert B. Jackson, Laurel J. Anderson, and William T. Pockman
Introduction
199
Theory and Currencies for Measuring Water in the Environment
199
Methods for Estimating Plant and Soil Moisture
201
Gravimetric Measurements of 9 m and 9 v
201
Techniques for Direct Measurement of 'II
202
Time Domain Reflectometry
204
Remotely Sensed Data Using Microwave Radiometers
206