Stable isotopes

Behind the scene – A day in Archaeological Science @BioArCh

On occasion of the Day of Archaeology 2015, I decided to take on the challenge of describing a typical day in the labs of BioArCh.

BioArch is a research group within the Department of Archaeology at the University of York that includes a wide range of expertise in human palaeoecology, paleodiet and environmental archaeology, with specific focus on the analysis of proteins, lipids, DNA and stable isotopes, human and other mammal and bird bones, molluscs, soils, microscopic remains of plants and animals.

The work in the lab is very varied and this video shows a part of my daily routine as a PhD student in Bioarchaeology. My project aims to reconstruct diet and food consumption in the multi-faith society of medieval Portugal, in which Muslims, Christians and Jews lived together for seven centuries. The main objectives are to identify if contemporaneous communities of Muslims and Christians showed different diets and if their diets changed after the Christian conquest of Portugal, completed in the 13th century. This project is included in a wider network researching the relation between food and faith. To know more about the project and the network, have a look on our blog.

In order to reconstruct the diet of past populations, small samples of bone are collected from human and animal skeletons. The next step is to extract the collagen from the bones. Once extracted, the collagen is then analysed and run through a machine called IRMS (isotope-ratio mass spectrometer) that provides the ratios of the stable isotopes of Carbon (delta 13C) and Nitrogen (delta 15N). The values of C and N inform on the consumption of meat, marine or river fish, and different types of plants (C3 vs C4).

The protocol for collagen extraction is composed of several steps. In this video I am cleaning a rib with a scalpel to get rid of the dirt on the surface (0:56), collecting some samples from the cold room that underwent demineralisation over night (1:19), rinsing the samples with water (1:48), making up a solution to favour the gelatinisation of the samples (1:59) and putting the samples in the oven where the gelatinisation is undertaken (2:16). In the last scene (2:25) I collect another batch of samples where gelatinisation was complete.

At this point the samples are half way through the protocol and a few more days will be necessary to get them ready for the analysis in the IRMS!

I hope you enjoy the video and hopefully it will give you an idea of what is going on in the lab.

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Alice Toso

On the Trail of the Elusive Fallow Deer…

Research paper, desk, keyboard, Archaeologist mug

I am a part-time postgraduate student, currently working towards an MSc in Archaeological Research at the University of Nottingham, which will take two years to complete. I’ve come back to archaeology after a long break, during which time I have pursued my career in research and academic computing. However, I am still in love with archaeology so my long-held ambition to do a further degree in the subject is at last being realised and I am really enjoying it, despite all the late nights reading and working on essays after I’ve finished my day job. As a mature student, I was concerned at first that I would find it difficult to fit in. However, the staff and my fellow students have been really encouraging, which is helping to make the whole experience very satisfying.

The taught part of our course has finished for this year, so it’s now time to get down to preparing for the research work which will form the basis of the 15,000 word dissertation we must submit and which accounts for a third of the credits on our course. I’m interested in the application of scientific techniques in archaeology, which has influenced my choices of modules, including archaeobotany and zooarchaeology, and my research will be using a fascinating technique, stable isotope analysis, to try to answer some interesting archaeological questions. (more…)