Use of stable isotopes to understand food webs and ecosystem functioning in estuaries

Stable isotopes have been extensively used to trace element cycles and their incorporation into food webs. This chapter provides a brief introduction to the principles of using stable isotopes as natural or deliberate tracers in estuarine systems, with a focus on (1) assessing the origin and cycling of organic and inorganic elements (mainly carbon and nitrogen), (2) defining estuarine food webs, (3) assessing animal movement or migration, and (4) interpreting stable isotope records in biogenic carbonates as proxies of (past) environmental conditions