Following his PhD he worked as a postdoctoral researcher in the Organic Geochemistry Unit in the School of Chemistry, University of Bristol, where he worked with Professor Geoffrey Eglinton and Professor James Maxwell to develop GC/MS and HPLC methodologies to investigate porphyrins in crude oils and source rocks.
These diverse areas are linked by his overarching interests in the preservation, recycling, decay and transport processes that impact biological materials once they enter the geosphere.
The wider aim of this research is to produce better models for nutrient cycles, which are central to understanding the effects of global warming and intensive agriculture.
This study of organic matter has also been applied to palaeoenvironment and palaeoclimatic reconstruction, using sedimentary archives such as ocean sediments and peat bogs.
His research suggests that milk was being processed in pots in Europe in the 7th millennium BC, well before the lactase persistence allele became common there.