Estelle Herrscher

Fe and Cu stable isotopes in archeological human bones and their relationship to sex.

Accurate sex assignment of ancient human remains usually relies on the availability of coxal bones or well-preserved DNA. Iron (Fe) and copper (Cu) stable isotope compositions ((56)Fe/(54)Fe and (65)Cu/(63)Cu, respectively) were recently measured in modern human blood, and an unexpected result was the discovery of a (56)Fe-depletion and a (65)Cu-enrichment in mens blood compared to womens blood. Bones, being pervasively irrigated by blood, are expected to retain the (56)Fe/(54)Fe and (65)Cu/(63)Cu signature of blood, which in turn is useful for determining the sex of ancient bones. Here, we report the (56)Fe/(54)Fe, (65)Cu/(63)Cu, and (66)Zn/(64)Zn ratios from a suite of well-preserved phalanxes (n = 43) belonging to individuals buried in the 17th and 18th centuries at the necropolis of Saint-Laurent de Grenoble, France, and for which the sex was independently estimated from pelvic bone morphology. The metals were purified from the bone matrix by liquid chromatography on ion exchange resin and the isotope compositions were measured by multiple-collector inductively coupled plasma mass spectrometry. The results show that, as expected from literature data on blood, male bone iron is depleted in (56)Fe and enriched in (65)Cu relative to female. No sex difference is found in the (66)Zn/(64)Zn ratios of bone. The concentration and isotopic data show no evidence of soil contamination. Four samples of five (77%) can be assigned their correct sex, a result comparable to sex assignment using Fe and Cu isotopes in blood (81%). Isotopic analysis of metals may therefore represent a valid method of sex assignment applicable to incomplete human remains.

Lapita Diet in Remote Oceania: New Stable Isotope Evidence from the 3000-Year-Old Teouma Site, Efate Island, Vanuatu

Remote Oceania was colonized ca. 3000 BP by populations associated with the Lapita Cultural Complex, marking a major event in the prehistoric settlement of the Pacific Islands. Although over 250 Lapita sites have been found throughout the Western Pacific, human remains associated with Lapita period sites are rare. The site of Teouma, on Efate Island, Vanuatu has yielded the largest burial assemblage (n = 68 inhumations) of Lapita period humans ever discovered, providing a unique opportunity for assessing human adaptation to the environment in a colonizing population. Stable isotope ratios (δ13C, δ15N, δ34S) of human bone collagen from forty-nine Teouma adults were analyzed against a comprehensive dietary baseline to assess the paleodiet of some of Vanuatus earliest inhabitants. The isotopic dietary baseline included both modern plants and animals (n = 98) and prehistoric fauna from the site (n = 71). The human stable isotope data showed that dietary protein at Teouma included a mixture of reef fish and inshore organisms and a variety of higher trophic marine (e.g. marine turtle) and terrestrial animals (e.g. domestic animals and fruit bats). The domestic pigs and chickens at Teouma primarily ate food from a C3 terrestrial environment but their δ15N values indicated that they were eating foods from higher trophic levels than those of plants, such as insects or human fecal matter, suggesting that animal husbandry at the site may have included free range methods. The dietary interpretations for the humans suggest that broad-spectrum foraging and the consumption of domestic animals were the most important methods for procuring dietary protein at the site. Males displayed significantly higher δ15N values compared with females, possibly suggesting dietary differences associated with labor specialization or socio-cultural practices relating to food distribution.

Southern French Neolithic Populations: Isotopic Evidence for Regional Specificities in Environment and Diet

The Middle Neolithic of the Northwestern Mediterranean area ( approximately 4500-3500 BC cal) is characterized by the development of food production techniques as well as by increasing social complexity. These characteristics could have had an impact on human dietary patterns. To evaluate human dietary practices and lifeways of the Middle Neolithic populations from the South of France, stable carbon and nitrogen isotope analysis was carried out on 57 human and 53 faunal bones from seven archaeological sites located in the Languedoc and Garonne regions between 20 and 100 km from the Mediterranean Sea, respectively. Results show regional differences in carbon isotope values. Animal and human bones from the Languedoc region are significantly enriched in (13)C relative to the Garonne. Conversely, human and dog bones from the Garonne region are significantly enriched in (15)N compared to human and dog bones from the Languedoc region. These results highlight the importance of the local ecosystem in human and animal diet as well as a regional differentiation of palaeodietary behavior, which probably relates to economic and social factors. The comparison of stable isotope data with archaeological and biological evidence does not show any significant intra- or interpopulation differences. However, the presence of human outliers suggests that migration probably occurred, perhaps in relation to the trade of animals and/or materials. This study also highlights the importance of investigating local animal stable isotope values for the interpretation of human palaeodiet.

Comportements alimentaires au Moyen Âge à Grenoble : application de la biogéochimie isotopique à la nécropole Saint-Laurent (XIIIe–XVe siècles, Isère, France)

Abstract Isotopic analysis of 13 C and 15 N of 47 bones from Saint-Laurent de Grenoble cemetery (Grenoble, Isere), from the end of medieval period (XIIIth–XVth centuries AD) allowed to define the food status of animals with regard to the humans and to discuss the variability amongst adults. Adults who died young and those with small stature may have had diets poor in animal protein. The consumption of animal proteins was more important in the XVth than in the XIVth century and could illustrate a typical urban food economy providing its population with a more diversified diet than in rural areas.

Evidence for Social and Cultural Change in Central Vanuatu Between 3000 and 2000 BP: Comparing Funerary and Dietary Patterns of the First and Later Generations at Teouma, Efate

ABSTRACT In the southern Melanesian islands of Vanuatu, as in New Caledonia, Fiji, and West Polynesia, the archaeological record indicates significant shifts in aspects such as patterns of settlement and mobility, landscape use, and pottery production, some 500 years (2500 BP) after initial colonization. The relatively uniform Lapita Cultural Complex, the first manifestation of human activity on these islands, was transformed in each archipelago into various distinctive cultural entities. Using dietary (δ13C and δ15N values measured in collagen) and mortuary data recorded in 43 Lapita and seven immediately Post-Lapita adult burials from the site of Teouma (Efate, Vanuatu), we demonstrate that these medium-term, transformative processes also affected the economic component of the social system as well as its symbolic and religious structures. Evolutionary change adapting to changing local conditions is envisioned as the likely dominant factor influencing this cultural trajectory, while environmental/climatic change, secondary migration, and internal social changes unrelated to adaptive processes could have interacted to produce the recorded patterns.

First Strontium Isotope Evidence of Mobility in the Neolithic of Southern France

AbstractThis study presents the first 87Sr/ 86Sr isotope results obtained on Neolithic humans from Southern France. These analyses aimed at exploring patterns of mobility in the Languedoc and Garonne areas, at sites dated to the Middle Neolithic (c. 4500–3500 cal bc). Strontium isotope analysis of tooth enamel and bone are a useful geochemical tracer to investigate the origin and residential mobility of ancient people. Strontium isotope ratios (87Sr/ 86Sr) of material from five sites located in two geographic areas were measured. Results obtained do not support our hypothesis of mobility for a number of individuals considered as outsiders in a previous study. On the other hand, the difference recorded between teeth and bone suggests mobility of other individuals between childhood and the last years of adult life. This preliminary study highlights the importance of combining multi-isotope analysis to discuss human subsistence economy and mobility.

An Analysis of the Last 1000 Years Human Diet on Tutuila (American Samoa) Using Carbon and Nitrogen Stable Isotope Data

This paper reports the first set of isotopic data relating to human diet from the Samoan Archipelago. Carbon and nitrogen stable isotope data measured on bone collagen were used to assess dietary patterns of prehistoric communities on Tutuila Island, American Samoa. We examined 14 human bones from three sites dated to three distinct periods: ~1,000 years ago (N = 5); -500 years ago (N = 8) and -150 years ago (N = 1). The isotopie data suggest that the human diet on Tutuila over the last 1,000 years was composed mainly of terrestrial resources with some consumption of coastal reef products. These data suggest a possible dietary change over time, with a higher dependence on marine resources in the earlier period shifting to a more terrestrial diet in the later period. Several possibilities for this dietary shift are suggested including: change in community specialization; marine resource depression; disintensification of marine procurement; intensification of horticultural production; and cultural or social changes in resource allocation.

Longitudinal Study of Stable Isotope Compositions of Maternal Milk and Implications for the Palaeo-Diet of Infants

The classic interpretation of stable isotope data from young children in an archaeological context is based on the hypothesis that the nitrogen isotope ratios present in breast milk remain identical throughout the breastfeeding period. This exploratory study assesses the changes in the nitrogen and carbon isotope ratios in maternal milk and in the nails of the mother and child, with the aim to evaluate the impact of variations in the stable isotope ratios in maternal milk on the tissues of children, and consequently on the reconstruction of the palaeo-diet of young children. The results show that the isotopic composition of maternal milk diminishes in relation to the mother’s tissues like nails and, by extrapolation, bones. The δ15N values of the milk vary little during the weeks of breastfeeding, but this is not the case for carbon, which varies considerably during the course of breastfeeding and weaning and does not seem to be linked to the mother’s diet and/or to the height and weight of the child. The difference between the δ15N values recorded for the mother’s and child’s nails is less than 2‰, which is lower than the values often cited in bioarchaeological literature. In addition, the data from this study does not confirm the hypothesis of a significant increase in heavy isotopes in the nails of newborn babies in relation to those of their mother at childbirth.RésuméL’interprétation des données isotopiques des jeunes enfants en contexte archéologique repose sur l’hypothèse que les rapports isotopiques de l’azote du lait maternel restent identiques tout au long de la période d’allaitement. Cette étude exploratoire propose d’appréhender, à partir du suivi longitudinal d’un couple mère–enfant sur 34 semaines, l’évolution des rapports isotopiques de l’azote mais également du carbone du lait maternel et des ongles de la mère et de l’enfant. La finalité est d’évaluer l’incidence des variations des rapports isotopiques du lait maternel sur les tissus des enfants et par conséquent sur la reconstitution de la paléoalimentation des tout-petits. Les résultats montrent que la composition isotopique du lait maternel est appauvrie par rapport aux tissus de la mère, comme les ongles, et par extrapolation à l’os. Les valeurs de δ15N du lait varient peu au cours des tétées, ce qui n’est pas le cas pour le carbone, dont l’importante variation au cours des semaines d’allaitement et de sevrage ne semble pas être en lien avec l’alimentation de la mère et/ou l’évolution staturopondérale de l’enfant. L’écart des valeurs de δ15N, enregistré entre les ongles de l’enfant et de la mère, est inférieur à 2‰, donc en dessous des valeurs souvent considérées dans la littérature bioarchéologique. De plus, les données de cette étude ne confirment pas l’hypothèse d’un enrichissement significatif en isotopes lourds des ongles des nouveau-nés relativement à ceux de leur mère à la naissance.

Urban and rural infant-feeding practices and health in early medieval Central Europe (9th-10th Century, Czech Republic).

In the Central European context, the 9th and 10th centuries are well known for rapid cultural and societal changes concerning the development of the economic and political structures of states as well as the adoption of Christianity. A bioarchaeological study based on a subadult skeletal series was conducted to tackle the impact of these changes on infant and young child feeding practices and, consequently, their health in both urban and rural populations. Data on growth and frequency of nonspecific stress indicators of a subadult group aged 0-6 years were analyzed. A subsample of 41 individuals was selected for nitrogen and carbon isotope analyses, applying an intra-individual sampling strategy (bone vs. tooth). The isotopic results attest to a mosaic of food behaviors. In the urban sample, some children may have been weaned during their second year of life, while some others may have still been consuming breast milk substantially up to 4-5 years of age. By contrast, data from the rural sample show more homogeneity, with a gradual cessation of breastfeeding starting after the age of 2 years. Several factors are suggested which may have been responsible for applied weaning strategies. There is no evidence that observed weaning strategies affected the level of biological stress which the urban subadult population had to face compared with the rural subadult population.

Copper and zinc isotope ratios in human bone and enamel

OBJECTIVES Here, we report Cu and Zn isotope ratios of bones and teeth of French people from various historical periods with the aim to understand how Cu and Zn isotope ratios of bone, a tissue that is continuously remodeled throughout life but that is prone to post-mortem diagenesis, compare with that of tooth enamel, a tissue that forms once during childhood but that is more resistant to diagenesis. Specifically, we examine (1) the potential existence of sex-related differences in the Cu isotope ratios (represented as δ65 Cu) in the tooth enamel of identified men and women, and (2) a decrease of Zn isotope delta ratios (represented as δ66 Zn) related to the increase of meat and fish consumption during the 20th century. METHODS Four series of material were studied: the archeological population of Saint-Laurent de Grenoble (17th -18th centuries AD), an anatomical collection of skulls (19th century AD), a contemporary anatomical collection of bones never buried, and contemporary teeth samples. The metals were purified by liquid chromatography and their isotopic ratios measured by means of multicollector inductively coupled plasma mass spectrometry. RESULTS We describe a clear offset between bone and tooth enamel for Zn isotope ratios, as previously observed in animals. There is a similar offset for Cu isotope ratios. We did not observe any difference between the δ65 Cu values of men and women when looking at dental enamel. For the contemporary samples, the δ66 Zn values of bioapatite decreased, which might be explained by the increase of animal product consumption among the French people during this period, notably when the access to seafood became widespread. CONCLUSIONS Our study demonstrates that the Cu and Zn isotope compositions of dental enamel are promising tools for childhood diet reconstruction. Meanwhile, the Cu isotope ratio of tooth enamel is unlikely to be useful for the identification of biological sex, even in the case of populations with early menarche. Further works are needed to understand the relationships between trophic level and Zn isotope ratios of human remains.