Improved 2D 1H-13C NMR permits in vivo analysis of Daphnia magna metabolism without isotopic enrichment

This dataset contains data from a study that assessed the feasibility of using nuclear magnetic resonance (NMR) to measure the real-time in vivo metabolic responses of the small freshwater crustacean, *Daphnia magna*, in samples derived from the wild (rather than raised in a laboratory) to investigate aquatic contaminant toxicity. To date, nearly all previous studies have used 13C isotopically enriched D.magna, but this limits studies to lab-raised organisms. These data were taken from an experimental approach that did not require isotopic enrichment, allowing samples to be taken directly from the environment. Due to overlap caused by the magnetic susceptibility distortions in 1D 1H NMR, 2D is required for metabolic fingerprinting in vivo. In particular, 2D 1H-13C NMR offers excellent spectral dispersion but is time-consuming and has intrinsic low sensitivity. To study D. magna in natural abundance, symmetric ASAP HSQC in combination with time-resolved non-uniform sampling (TR-NUS) was used. This combined approach (TR-NUS ASAP HSQC) improved sensitivity up to 3 times versus standard HSQC, while reconstruction of TR-NUS data provided information on a 4 minute time scale. In turn, this allowed anoxia (and recovery from anoxia) to be studied for the first time on unlabelled Daphnia using HSQC. This method could, therefore, become key for investigating environmental adaptability and exposure in living organisms in conditions that are closer to real-time.