Ratios of barium and strontium concentrations in skeletal samples (e.g. in the logarithmic form lg(Ba/Sr)), are a possible alternative or supplementary marker to stable carbon isotope ratios (δ¹³C) for identification of marine food consumption. Previous studies have compared lg(Ba/Sr) values between different species of animals with differing diets, but few studies have been performed where animals of the same species consumed known diets ranging from completely terrestrial to completely marine. Additionally, how seaweed consumption affects dental and bone Ba, Sr and other trace element concentrations has not yet been directly investigated.

In this study, tooth enamel from modern sheep (n = 15) that consumed known diets containing varying amounts of terrestrial grasses and seaweeds were analysed for their Sr, Ba, Ca, V, Mn, Co, Ni, As, and U concentrations. Additionally, δ¹³C values were analysed to enable comparison of δ¹³C and trace element ratios as markers of marine plant food consumption. The consumed vegetation types (grasses and seaweeds) were also analysed for trace element ratios, as were soils and sands from areas where the animals were pastured. To investigate how decay processes (i.e., diagenesis) may affect lg(Ba/Sr) in archaeological tooth enamel, teeth of 22 sheep from seven archaeological sites (ranging from ca. 5000 to 1000 years old) on the Orkney Islands, Scotland, were also analysed.

The results show that tooth enamel from seaweed-eating sheep had significantly different lg(Ba/Sr) (−2.4 to −1.6) and δ¹³C values (−6.7‰ to −3.3‰) when compared to terrestrial-feeding sheep (lg(Ba/Sr) 0.6 to −0.5; δ¹³C −15.5‰ to −14.7‰), with a linear correlation between lg(Ba/Sr) and δ¹³C (R² = 0.94). Vegetation, soil and sand results confirmed the assumed dependence of enamel lg(Ba/Sr) values on the (bioaccessible) Ba and Sr concentrations of the consumed matter. The archaeological samples had elevated relative amounts of U, V, As, Mn, Co, and Ni, attributable to diagenesis. However, the lg(Ba/Sr) values of the archaeological enamel followed the trend established using the modern samples, indicating that diagenesis did not cause significant changes in lg(Ba/Sr) in these samples. In conclusion, lg(Ba/Sr) values in enamel appear to be a useful indicator of the relative amount of marine food consumed, including seaweeds. This may be particularly advantageous for samples and locations where δ¹³C is unreliable or ambiguous as an indicator of marine food consumption.

^{骨骼样品中钡和锶浓度的比率（例如，以对数形式 lg(Ba/Sr)）可能是稳定碳同位素比率 (δ 13} C)的替代或补充标记，用于识别海洋食物消费。以前的研究比较了具有不同饮食的不同物种动物之间的 lg(Ba/Sr) 值，但很少有研究表明同一物种的动物食用从完全陆地到完全海洋的已知饮食。此外，尚未直接研究海藻消费如何影响牙齿和骨骼 Ba、Sr 和其他微量元素浓度。

在这项研究中，分析了来自现代绵羊（n = 15）的牙釉质，这些绵羊食用了含有不同数量陆生草和海藻的已知饮食，以了解它们的 Sr、Ba、Ca、V、Mn、Co、Ni、As 和 U 浓度。此外，还分析了 δ ¹³ C 值，以比较 δ ¹³ C 和微量元素比率作为海洋植物食物消耗的标志物。还分析了消耗的植被类型（草和海藻）的微量元素比率，以及来自动物放牧地区的土壤和沙子。为了研究腐烂过程（即成岩作用）如何影响考古牙釉质中的 lg(Ba/Sr)，来自苏格兰奥克尼群岛的 7 个考古遗址（约 5000 至 1000 年）的 22 只羊的牙齿被研究也进行了分析。

结果表明，食海藻绵羊的牙釉质与陆食绵羊（^lg (Ba/Sr) 0.6 至 -0.5；δ ¹³ C -15.5‰ 至 -14.7‰)，lg(Ba/Sr) 与 δ ¹³ C (R ² = 0.94)。植被、土壤和沙子结果证实了釉质 lg(Ba/Sr) 值对消耗物质的（生物可接近的）Ba 和 Sr 浓度的假设依赖性。由于成岩作用，考古样品中 U、V、As、Mn、Co 和 Ni 的相对含量升高。然而，考古珐琅质的 lg(Ba/Sr) 值遵循使用现代样品建立的趋势，表明成岩作用并未导致这些样品中 lg(Ba/Sr) 的显着变化。总之，牙釉质中的 lg(Ba/Sr) 值似乎是衡量包括海藻在内的海洋食物相对消耗量的有用指标。^{这对于 δ 13} C 作为海洋食品消费指标不可靠或模棱两可的样品和位置可能特别有利。