Biokinetics and discrimination factors for δ13C and δ15N in the omnivorous freshwater crustacean, Cherax destructor

J. Veliscek Carolan*, D. Mazumder, C. Dimovski, R. Diocares, J. Twining

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Knowledge and understanding of biokinetics and discrimination factors for carbon-13 (δ13C) and nitrogen-15 (δ15N) are important when using stable isotopes for food-web studies. Therefore, we performed a controlled laboratory diet-switch experiment to examine diettissue and dietfaeces discrimination factors as well as the biokinetics of stable-isotope assimilation in the omnivorous freshwater crustacean, Cherax destructor. The biokinetics of δ13C could not be established; however, the δ15N value of C. destructor tissue reached equilibrium after 80±35 days, with an estimated biological half-time for 15N of 195 days. Metabolic activity contributed to the turnover of δ 15N by nearly an order of magnitude more than growth. The diettissue discrimination factors at the end of the exposure were estimated as 1.1±0.5% for δ13C and +1.51.0% for δ15N, indicating that a δ15N diettissue discrimination factor different from the typically assumed +3.4% may be required for freshwater macroinvertebrates such as C. destructor. The dietfaeces discrimination factor for δ15N after 120 days was estimated as +0.90.5%. The present study provides an increased understanding of the biokinetics and discrimination factors for a keystone freshwater macroinvertebrate that will be valuable for future food-web studies in freshwater ecosystems.

Original languageEnglish
Pages (from-to)878-886
Number of pages9
JournalMarine and Freshwater Research
Volume63
Issue number10
DOIs
Publication statusPublished - 2012
Externally publishedYes

Keywords

  • biokinetics
  • Cherax destructor
  • fractionation
  • laboratory study
  • stable isotopes

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