Aquatic resources in human diet in the Late Mesolithic in Northern France and Luxembourg: insights from carbon, nitrogen and sulphur isotope ratios

摘要

We investigated the contribution of freshwater resources to the diet of seven Late Mesolithic hunter-gatherers (ca. 5300-7000 BC) from Northern France and Luxembourg using stable isotope ratios. In addition to the carbon and nitrogen stable isotope ratios (delta C-13, delta N-15), we explored the potential of the sulphur isotopic ratios (delta S-34) to detect and quantify the proportion of protein derived from aquatic foodstuff. In only two sites, animal remains from an associated settlement were available and subsequently examined to decipher the isotopic differential between terrestrial and freshwater resources. The quantification of their relative contribution was simulated using a Bayesian mixing model. The measurements revealed a significant overlap in delta C-13 values between freshwater and terrestrial resources and a large range of delta N-15 values for each food category. The delta S-34 values of the aquatic and terrestrial animals were clearly distinct at the settlement in the Seine valley, while the results on fish from Belgium demonstrated a possible overlap in delta S-34 values between freshwater and terrestrial resources. Local freshwater ecosystem likely contributed to ca. 30-40 % of the protein in the diet of the individuals found in the Seine settlement. Out of this context, the isotopic signature and thus contribution of the available aquatic foods was difficult to assess. Another potential source of dietary protein is wild boar. Depending on the local context, collagen delta S-34 values may contribute to better assessment of the relative contribution of freshwater and terrestrial resources.