Heavy Isotope Enrichments

Abstract “Heavy Isotope Enrichments” reviews concepts for developing and interpreting heavy isotope labeling studies in ecology. The chapter compares continuous- and pulse-labeling approaches for the 13C labeling of plant material. Methods for the application of isotope-labeled substrates and their use in stable isotope probing of biological markers are presented. Calculations of the heavy isotope excess and the quantification of the recovery of heavy isotope additions in isotope tracing studies are provided. Principles and equations for the application of the isotope dilution method are illustrated, and its limitations are discussed. Examples of applications for carbon, nitrogen, and water stable isotopes are presented.