Abstract

Stable isotope analysis (SIA) is an elementary technique in food web ecology, but its insights become increasingly ambiguous in complex systems. One approach to elevate the utility of SIA in such systems is the use of heavy isotope tracers (i.e., labeling). However, the fundamental assumption that the addition of such tracers does not affect in situ conditions has been challenged. This study tests if labeling is suitable for autotrophy-based and detritus-based aquatic food webs. For the former, the survival and reproduction of Daphnia magna fed with phytoplankton cultured at different levels of 15N addition were assessed. For the latter, the microbial decom-position of leaf litter was assessed at the same tracer levels. While no significant differences were observed, effect patterns were comparable to a previous study, supporting the isotopic redundancy hypothesis that postulates discrete quantum mechanical states at which the reaction speeds of metabolic processes are altered. Although physiology (reproduction) and activity (microbial decomposition) might not be altered to an ecologically sig-nificant level, labeling with heavy stable isotopes could potentially affect isotopic fractionation in biochemical processes and bias conclusions drawn from resulting SI ratios.

Keywords

Stable isotope analysis; Stable isotope labeling; Isotopic resonance

Published in

Aquatic Toxicology
2023, Volume: 259, article number: 106542
Publisher: ELSEVIER

SLU Authors

• Bundschuh, Mirco

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    
  • University of Kaiserslautern-Landau (RPTU)

UKÄ Subject classification

Environmental Sciences


Publication identifier

DOI: https://doi.org/10.1016/j.aquatox.2023.106542

Permanent link to this page (URI)

https://res.slu.se/id/publ/122323