Variability in isotope discrimination factors in coral reef fishes: implications for diet and food web reconstruction

Wyatt, Alex S. J. and Waite, Anya M. and Humphries, Stuart (2010) Variability in isotope discrimination factors in coral reef fishes: implications for diet and food web reconstruction. PLoS ONE, 5 (10). ISSN 1932-6203

Full content URL: http://www.plosone.org/article/info%3Adoi%2F10.137...

Documents
Variability in isotope discrimination factors in coral reef fishes: implications for diet and food web reconstruction
[img]
[Download]
[img]
Preview
PDF
__ddat02_staffhome_jpartridge_fetchObject.pdf - Whole Document
Available under License Creative Commons Attribution Share Alike.

525kB
Item Type:Article
Item Status:Live Archive

Abstract

Interpretation of stable isotope ratios of carbon and nitrogen (δ13C and δ15N) is generally based on the assumption that with each trophic level there is a constant enrichment in the heavier isotope, leading to diet-tissue discrimination factors of 3.4‰ for 15N (ΔN) and ~0.5‰ for 13C (ΔC ). Diet-tissue discrimination factors determined from paired tissue and gut samples taken from 152 individuals from 26 fish species at Ningaloo Reef, Western Australia demonstrate a large amount of variability around constant values. While caution is necessary in using gut contents to represent diet due to the potential for high temporal variability, there were significant effects of trophic position and season that may also lead to variability in ΔN under natural conditions. Nitrogen enrichment increased significantly at higher trophic levels (higher tissue δ15N), with significantly higher ΔN in carnivorous species. Changes in diet led to significant changes in ΔN, but not tissue δ15N, between seasons for several species: Acanthurus triostegus, Chromis viridis, Parupeneus signatus and Pomacentrus moluccensis. These results confirm that the use of meta-analysis averages for ΔN is likely to be inappropriate for accurately determining diets and trophic relationships using tissue stable isotope ratios. Where feasible, discrimination factors should be directly quantified for each species and trophic link in question, acknowledging the potential for significant variation away from meta-analysis averages and, perhaps, controlled laboratory diets and conditions. © 2010 Wyatt et al.

Keywords:nitrogen, nitrogen 15, isotope, accuracy, animal tissue, article, Australia, carnivore, controlled study, coral reef, diet, environmental enrichment, fish, food web, intestine, isotope analysis, nonhuman, seasonal variation, animal, Anthozoa, food chain, species difference, Acanthurus triostegus, Chromis viridis, Parupeneus spilurus, Pisces, Pomacentrus moluccensis, Animals, Fishes, Isotopes, Species Specificity, Western Australia
Subjects:C Biological Sciences > C161 Marine Biology
Divisions:College of Science > School of Life Sciences
Related URLs:
ID Code:15257
Deposited On:06 Oct 2014 11:52

Repository Staff Only: item control page