Influence of Climate on Stable Nitrogen Isotopic Values of Contemporary Greek Samples: Implications for Isotopic Studies of Human Remains from Neolithic to Late Bronze Age Greece

Elissavet Dotsika,Georgios Diamantopoulos

doi:10.3390/geosciences9050217

Elissavet Dotsika, Georgios Diamantopoulos

Open Access

https://doi.org/10.3390/geosciences9050217

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Abstract

In this paper, we study δ15N enrichment as an indicator not only of marine protein diet, but also of climate change. The slope of the variation of δ15N with precipitation was calculated equal to 0.38/100 mm of precipitation for Greek plants, 0.38/100 mm of precipitation for herbivores, and 0.32/100 mm of precipitation for the Greek human population (hair samples). As a case study, the slope was used to re-evaluate the published mean δ15N human bone collagen values from the Early Neolithic to Late Bronze Age for 22 archaeological sites. The results indicate that climate has a significant impact on the final δ15N values of plant and animal tissues. Furthermore, for the same sites, we investigated the intra-site diet patterns, while taking into account the environmental effect on the observed δ15N human bone collagen values.

Highlights

Dietary reconstruction using stable nitrogen isotope analysis of bone collagen reproduces the trophic level or the position of an individual in the food chain
This paper examines the effect of precipitation on δ15 N values of modern plants and animal tissues in Greece
We present a re-evaluation of the δ15 N published results of human bones from 22 archaeological sites dating from Early Neolithic to Late Bronze Age

Summary

Introduction

Dietary reconstruction using stable nitrogen isotope analysis of bone collagen reproduces the trophic level or the position of an individual in the food chain. The δ15 N value of human bone collagen is about 3 mUr higher than the δ15 N value of the protein that the human has consumed [2,3,4]. Humans who obtain the majority of their dietary protein from marine species have δ15 N values ranging from about 12 to 22 mUr [5,6], while those who consume only terrestrial protein sources have δ15 N between 5 and 12 mUr. Climate may affect the δ13 C and δ15 N values of terrestrial animals through its effect on the δ C of plants and on the δ15 N of soil, at the base of the food chain. This range of values probably arises from the climatologically-sensitive processes of bacterial N2 fixation, nitrification, and de-nitrification [8,9,10]

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