The influence of circadian variables on ecotoxicology metabolomics

Ecotoxicologists are using metabolomics increasingly to gain insight into toxicological mechanisms and sublethal effects of chemical exposures. Metabolomics offers a sensitive multi-parameter approach that can detect biochemical responses not obvious using apical and behavioural endpoints. This includes the responses to very low-dose toxicant exposures, variations in the physico-chemical state of experimental media, and even the progression of circadian rhythms. Consequently, repeatability and comparability of metabolomics experiments relies on the control and reporting of these features. In this systematic quantitative literature review, we examine recent ecotoxicology research to determine the rate and quality of reporting of circadian timing and other variables that influence circadian rhythms and the associated metabolome. We found that most circadian variables are underreported and call for further research into the influence of their manipulation on the metabolome.