Vital effects in biominerals
For my PhD work I examined the influence of intrinsic and extrinsic factors on otolith trace element incorporation, performing extensive literature reviews and a long-term "mensurative" experiment examining seasonal changes in seawater, blood, and otolith element concentrations. The results suggest that in a fully marine environment, where physico-chemical variations are relatively small, physiological signals (e.g. growth, reproduction, stress) can outweigh environmental signals, potentially confusing movement reconstructions that rely on spatially explicit, environmental markers.
We also analyzed the otoliths of free-ranging plaice with known migration patterns based on data storage tags (see image, right) to validate the use of otolith oxygen isotope and trace element concentrations to reconstruct migration patterns.
Plaice (Pleuronectes platessa) with a data storage tag used to reconstruct its migration patterns in the North Sea and English Channel (photo credit: CEFAS; see papers by Ewan Hunter et al).
Taking monthly blood samples from plaice at CEFAS, Lowestoft to examine the relationship between water-blood-otolith element concentrations in mature and immature marine fish.