PALEODIET: Calibration and application of novel stable isotope (Ca, Sr and Zn) proxies for paleodietary reconstructions

我们吃什么就是什么：饮食可以从人类骨骼和牙齿的稳定同位素组成中推断出来，人们已经对这些同位素组成进行了40年的研究，以重建过去人群的饮食。利用氮、碳同位素对人类古饮食的研究取得了很大进展。然而，这些经典的饮食代用指标，特别是胶原蛋白为基础的氮同位素，由于成岩偏倚，往往难以应用于5万年BP以上。因此，旧石器时代人类的饮食不容易评估。古饮食研究项目的目标是：1)校准和结合新的非传统稳定同位素（Zn, Ca, Sr）代理，能够评估目前无法获得的饮食信息；2)应用这个新的同位素工具箱，为尼安德特人的饮食提供前所未有的见解，并使我们能够测试流行的喂养假设。锌、钙和稳定锶同位素组成的变化可以用来识别目前膳食代用物无法识别的食物来源，并量化不同食物类别的消费。该提案主要关注三个主题：1)表征重要人类食物来源的锌同位素组成；2)评估旧石器时代食物网和尼安德特人饮食中的骨髓和脂肪消耗；3)确定巴西和葡萄牙原始人对鱼类和贝类的利用。通过对现代和旧石器时代上/中期动物和人类遗骸进行Zn、Ca和Sr稳定同位素的校准和应用，我们将开发出新的饮食代用物，这些代用物有可能应用于古代化石骨骼遗骸。这将为主要饮食转变（即首次食用动物蛋白和贝类）与人类谱系的主要进化步骤之间的联系提供新的见解。

We are what we eat: diet can be inferred from stable isotope compositions of bones and teeth of humans which have been studied since 40 years to reconstruct the diets of past populations. Much progress has been made in the field of human paleodiet research using nitrogen and carbon isotopes. However, these classical dietary proxies, especially the collagen-based nitrogen isotopes, are due to diagenetic biases often difficult to apply beyond 50,000 years BP. Paleolithic hominin diets can therefore not be easily assessed. The objectives of the PALEODIET research project are to: 1) calibrate and combine new non-traditional stable isotope (Zn, Ca, Sr) proxies capable of assessing dietary information currently beyond reach, 2) apply this new isotope toolbox to provide uprecedent insights into Neanderthal diets and enable us to test prevailing feeding hypotheses. Variations in Zn, Ca and stable Sr isotopic compositions can be used to fingerprint food sources that cannot be identified with current dietary proxies and quantify the consumption of different food categories. This proposal focuses on three main topics: 1) characterize the zinc isotope compositions of important human food sources, 2) assess bone marrow and fat consumption in Paleolithic food webs and Neanderthal diets, 3) determine fish and shellfish exploitation of protohistoric populations from Brazil and Portugal. By calibrating and applying Zn, Ca as well as stable Sr isotopes on modern and upper/middle Paleolithic faunal and human remains, we will develop new dietary proxies that have the potential to be applied to ancient fossil skeletal remains. This will provide new insights into the link between major dietary transitions (i.e. first animal protein and shellfish consumption) and main evolutionary steps of the human lineage.