Details of Award
NERC Reference : NE/J010510/1
Unravelling the Nitrogen Isotope Signal of Skeletal Collagen for Palaeodeitary Reconstruction: The Origin of the Nitrogen Isotope Trophic Level Effect
Grant Award
- Principal Investigator:
- Professor RP Evershed, University of Bristol, Chemistry
- Co-Investigator:
- Dr B Miller, University of Bristol, Clinical Veterinary Science
- Co-Investigator:
- Professor J Tarlton, University of Bristol, Clinical Veterinary Science
- Grant held at:
- University of Bristol, Chemistry
- Science Area:
- Earth
- Freshwater
- Marine
- Terrestrial
- Overall Classification:
- Terrestrial
- ENRIs:
- Biodiversity
- Global Change
- Natural Resource Management
- Science Topics:
- Palaeobiology
- Prehistoric Archaeology
- Science-Based Archaeology
- Protein chemistry
- Analytical Science
- Abstract:
- When an organism eats it digests the biochemical components of the food to either grow new tissues or derive energy to sustain itself. In doing this the major elements, e.g. C and N, from the different parts of the diet are incorporated into the tissues of the consumer organism. This has given rise to the adage "you are what you eat". More than 30 years ago researchers realised that the stable isotopic compositions of the major elements making up the nutrients in the diet namely, 13C/12C and 15N/14N, vary between different plants and animals as a result of such factors as the differing biosynthetic and metabolic pathways giving rise to different biochemical components or the differing stable isotope compositions of the C and N sources at the base of food chains. The above phenomena gave rise to an ingenious new way of studying the diets of fossil organisms, including prehistoric humans. Stable C and N isotope signatures of preserved biochemicals in skeletal remains from archaeological sites were compared with the stable isotope values of potential foods, allowing the diet of the consumer to be inferred. The new discipline has the title "palaeodietary reconstruction". A major reason for the success of this new field was the fact that the major structural skeletal protein, collagen, has been found to be widely preserved in ancient skeletal remains many 1000s of years old. A major observation is that the N isotope value of an organism is higher than its diet. This phenomenon is termed the "trophic level effect". Thus, the N isotope value of herbivores are higher than that of the plants they eat, and the N isotope value of a carnivore is higher than that of the herbivores it eats. Hence, N isotope value of a human, will lie somewhere in between the values of the plants and animals he or she eats. Remarkably, although this effect has been used in research reported in several thousand publications, the underlying mechanics of N trophic enrichment within the amino acids (AAs) that comprise the major body proteins are unknown. The aim of our research is to bridge this knowledge gap. Until recently the same problem existed for C isotopes but this gap in knowledge has begun to be filled as a result of us exploiting a range of new analytical techniques which allow the C isotope compositions of individual compounds to be recorded at high precision. In the case of the structural protein collagen this involves breaking it down to its constituent AAs, from which their C isotope compositions can be determined, revealing the origin of the collagen C isotope signal. Through this approach we have revealed how C is incorporated from different dietary macronutrients and identified dietary components which would not have been seen using whole collagen measurements. The aim of this new project is to undertake analogous analyses of the N isotope compositions of the AAs that make up structural proteins. N isotope analyses are technically very difficult to perform; however, we recently published the first systematic determinations of AA N isotopes for prehistoric humans and their diets. We will apply this approach to provide the necessary understanding of the N tropic effect by analysing the AA components of the proteins in various tissues of animals and their diets, including those derived from: (i) a unique controlled pig feeding experiment (pigs being accepted as excellent animal models for humans) in which the animals were raised on both plant and animal protein based diets, (ii) tissue culture experiments which will allow cellular and whole organism effects to be resolved for the first time, (iii) key organisms sampled from marine food webs, which are particularly interesting as they express the N trophic effect most strongly, and (iiv) a range of archaeological human and animal skeletal remains from regions where varying amounts of marine and terrestrial foods would have been consumed, to reveal population level variation.
- NERC Reference:
- NE/J010510/1
- Grant Stage:
- Completed
- Scheme:
- Standard Grant (FEC)
- Grant Status:
- Closed
- Programme:
- Standard Grant
This grant award has a total value of £333,988
FDAB - Financial Details (Award breakdown by headings)
| DI - Other Costs | Indirect - Indirect Costs | DA - Investigators | DA - Estate Costs | DI - Staff | DA - Other Directly Allocated | DI - T&S |
|---|---|---|---|---|---|---|
| £27,084 | £108,221 | £45,423 | £47,501 | £101,459 | £1,563 | £2,737 |
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