Trans-Atlantic slavery: Isotopic evidence for forced migration to Barbados

Stable Isotope Provenance of Unidentified Deceased Migrants-A Pilot Study

In the global migration crisis, one of the challenges in the effort to identify deceased migrants is establishing their region of origin, which facilitates the search for ante mortem data to be compared with the post mortem information. This pilot study explores the potential of using stable isotope analysis to distinguish between individuals coming from West Africa and the Horn of Africa. Six individuals (four of known origin and two of unknown origin) were sampled. δ13CVPDB(keratin), δ15NVPDB(keratin) and δ18OVSMOW(keratin) of hair were analysed using Elemental Analyzers coupled with Isotope Ratio Mass Spectrometry (IRMS). δ18OVSMOW(carbonate) and δ13CVPDB(carbonate) of bone were analysed using GasBench II with IRMS, while 87Sr/86Sr composition was determined in bone and dental enamel using laser ablation multi-collector inductively coupled plasma mass spectrometry. The stable isotope compositions of the individual from the Horn of Africa differed from the other individuals. The differences found between 87Sr/86Sr of enamel and bone and between δ18O and δ13C in bone and hair reflect changes in sources of food and water in accordance with regionally typical migration journeys. The analysis of multiple stable isotopes delivered promising results, allowing us to narrow down the region of origin of deceased migrants and corroborate the information about the migration journey.

“Celts” up and down the Alps. Insights on mobility patterns in the pre‐Roman /Celtic population from Verona ( NE Italy, 3rd–1st c. BCE ): A multi‐isotopic approach

Objectives

The Late Iron Age in continental Europe featured complex demographic processes including, among others, the establishment of transalpine “Celtic” communities on the Italian peninsula between the 4th and 1st centuries BCE. To date, only few data are available about mobility and migration in these populations. Here we explore these topics among the Cenomani of Seminario Vescovile (SV‐Verona, Italy, 3rd–1st c. BCE) through a multi‐isotopic approach and test the possible associations with sex, age and funerary treatment.

Materials and methods

We analyzed isotopic ratios of oxygen (δ¹⁸O) and carbon (δ¹³C) from bone phosphate and collagen, respectively, of 49 individuals (23 males, 17 females, and 9 nonadults). In addition, we explored possible intraindividual lifetime changes by comparing collagen δ¹³C from bone and dentine of 26 individuals. We assessed nonlocality based on individual deviation of isotopic values from the population mean plus three times the median absolute deviation from the median (±3MAD). We then checked for isotopic differences between sexes and type of funerary treatment using Mann–Whitney tests.

Results

One individual shows isotopic values consistent with a nonlocal origin. Five more individuals may have originated from a different locality. No statistical differences separate sexes and types of funerary treatment.

Discussion

Results suggest a local origin of most of the individuals of SV with the few exceptions pointing especially to an Alpine origin. The low frequency of nonlocals at SV suggest a reduced mobility in this population, or the preeminence of short distance movements undetected by our analyses.

Assessing the preservation of biogenic strontium isotope ratios (87 Sr/86 Sr) in the pars petrosa ossis temporalis of unburnt human skeletal remains: A case study from Saba

RATIONALE

Strontium isotope (⁸⁷ Sr/⁸⁶ Sr) analysis of skeletal remains has become a powerful tool in archaeological studies of human migration and mobility. Owing to its resistance to post-mortem alteration, dental enamel is the preferred sampling material used for ⁸⁷ Sr/⁸⁶ Sr analysis in bioarchaeological provenance research, although recent studies have demonstrated that cremated bone is also generally resistant to diagenesis. This paper presents the results of a pilot study exploring the potential of unburnt petrous bone (pars petrosa) as a reservoir of biogenic (diagenetically unaltered) strontium, as the otic capsule or bony labyrinth within the petrous bone is extremely dense and is thought to be unable to remodel after early childhood, potentially providing an alternative for dental enamel.

METHODS

From an individual from a colonial-era (18th century) site on the island of Saba in the Caribbean for whom previous enamel ⁸⁷ Sr/⁸⁶ Sr results had indicated non-local origins, multiple locations (n = 4) on the petrous were sampled and measured for strontium isotope composition. Saba (13 km² ) has been extensively mapped for baseline strontium isotopes (n = 50) with ⁸⁷ Sr/⁸⁶ Sr varying from ca 0.7065 to 0.7090, whereas enamel ⁸⁷ Sr/⁸⁶ Sr (n = 3) ranged from 0.7104 to 0.7112.

RESULTS

All four petrous ⁸⁷ Sr/⁸⁶ Sr ratios (0.7111-0.7122) are consistently and considerably higher than the local bioavailable range, and very similar to the enamel ⁸⁷ Sr/⁸⁶ Sr. These results provide initial evidence that unburnt petrous bones may preserve biogenic strontium, at least in this specific burial context.

CONCLUSIONS

While more research in diverse burial conditions is needed to validate this observation, if confirmed, it would have broader implications for sample selection strategies in bioarchaeological studies using the strontium isotope method.

Investigating individual migration life histories: An isotopic case study from 17th to 18th century Nouvelle France

OBJECTIVES

This isotopic study explores the mobility patterns of a growing urban population from Notre Dame's Catholic cemetery (1691-1796), located in Montreal (Canada). The site offers a unique opportunity to investigate early colonial settlement in Nouvelle France through individual life patterns.

MATERIALS AND METHODS

Stable oxygen isotopic compositions (δ¹⁸O) were measured on the enamel of 32 individuals from the Notre Dame collection. Premolars and third molars were selected, as they reflected the δ¹⁸O of the drinking water during childhood (2.5-5.5 years) and pre-adulthood (9.5-15.5 years). Firstly, premolars from three children (4-8 years of age) allowed us to provide a mean δ¹⁸O for the water consumed locally (22.7 ±  1.0 ‰ vs. VSMOW). Then, our δ¹⁸O were compared with published data from various geographical regions in North America (Eastern Canada and the United States) and Europe (France and the British Isles) to highlight mobility patterns of each individual.

RESULTS

Forty-eight percent of our sample (14 out of 29 individuals) did not reflect any long-distance mobility, as all their δ¹⁸O reflected Montreal's variation during their lifetime. The remaining (15 out of 29 individuals) experienced mobility within (n = 8) and outside (n = 7) North America and at different phases of their life (five at pre-adulthood, six at adulthood and four during both phases). Their migration patterns were analyzed according to age, sex, diet and possible ancestry in order to propose some "biographies."

DISCUSSION

This study highlights high population diversity in early colonial Montreal. Historians wrote that the city was growing, not only with the arrival of Europeans (e.g., young male workers, sailors), but also other groups (e.g., Indigenous people, slaves from North America). Additional analyses (e.g., ancient DNA) will be needed to explore further this phenomenon.

Sidon on the breadth of the wild sea: Movement and diet on the Mediterranean coast in the Middle Bronze Age

OBJECTIVES

Excavations at Sidon (Lebanon) have revealed dual identities during the Middle Bronze Age (ca. 2000-1600 BCE): a maritime port and center for local distribution, as well as a settlement with a heavy subsistence dependence on the extensive inland hinterlands. We aim to investigate residential mobility at Sidon using isotopic analyses of 112 individuals from 83 burials (20 females, 26 males, and 37 subadults). Veneration and remembrance of the dead is evident from funerary offerings in and near the tombs. With marine fish a major component in funerary offerings, we predict major marine reliance in this coastal population.

MATERIALS AND METHODS

New isotopic evidence of paleomobility (⁸⁷ Sr/⁸⁶ Sr, δ¹⁸ O) and diet (δ¹³ C_carbonate ) is the focus of this research. Previous bulk bone collagen δ¹³ C and δ¹⁵ N analysis is strengthened by further sampling, along with δ³⁴ S where collagen yield was sufficient.

RESULTS

The five non-locals identified (8.9% of the 56 analyzed) come from constructed tombs with high-status grave goods except for one, which was heavily disturbed in antiquity. Dietary investigation of the population confirms reliance on terrestrial resources with no significant marine input. No significant differences in diet between the sexes or burial types are present.

CONCLUSIONS

Although Sidon was part of a growing Mediterranean network evidenced through artefactual finds, relatively low immigration is evident. While religious feasts venerating the dead may have involved significant piscine components, no appreciable marine input in diet is observed. Fish may have been reserved for the deceased or only consumed on feast days alongside the dead rather than a regular part of the Bronze Age menu.

Ancient viral genomes reveal introduction of human pathogenic viruses into Mexico during the transatlantic slave trade

After the European colonization of the Americas, there was a dramatic population collapse of the Indigenous inhabitants caused in part by the introduction of new pathogens. Although there is much speculation on the etiology of the Colonial epidemics, direct evidence for the presence of specific viruses during the Colonial era is lacking. To uncover the diversity of viral pathogens during this period, we designed an enrichment assay targeting ancient DNA (aDNA) from viruses of clinical importance and applied it to DNA extracts from individuals found in a Colonial hospital and a Colonial chapel (16th-18th century) where records suggest that victims of epidemics were buried during important outbreaks in Mexico City. This allowed us to reconstruct three ancient human parvovirus B19 genomes and one ancient human hepatitis B virus genome from distinct individuals. The viral genomes are similar to African strains, consistent with the inferred morphological and genetic African ancestry of the hosts as well as with the isotopic analysis of the human remains, suggesting an origin on the African continent. This study provides direct molecular evidence of ancient viruses being transported to the Americas during the transatlantic slave trade and their subsequent introduction to New Spain. Altogether, our observations enrich the discussion about the etiology of infectious diseases during the Colonial period in Mexico.

A global carbon and nitrogen isotope perspective on modern and ancient human diet

Stable carbon and nitrogen isotope analyses are widely used to infer diet and mobility in ancient and modern human populations, potentially providing a means to situate humans in global food webs. We collated 13,666 globally distributed analyses of ancient and modern human collagen and keratin samples. We converted all data to a common "Modern Diet Equivalent" reference frame to enable direct comparison among modern human diets, human diets prior to the advent of industrial agriculture, and the natural environment. This approach reveals a broad diet prior to industrialized agriculture and continued in modern subsistence populations, consistent with the human ability to consume opportunistically as extreme omnivores within complex natural food webs and across multiple trophic levels in every terrestrial and many marine ecosystems on the planet. In stark contrast, isotope dietary breadth across modern nonsubsistence populations has compressed by two-thirds as a result of the rise of industrialized agriculture and animal husbandry practices and the globalization of food distribution networks.

87Sr/86Sr in Archeological and Paleobiological Research: A Perspective

The stable isotope ratio 87Sr/86Sr has been shown to have extraordinary potential for documenting the movement and life-histories of humans and other animals, both in history and prehistory. Thirty years of expanding applications has taken the method from a niche (if not fringe) approach to a normal part of archeological and paleobiological enquiry; indeed a “Golden Age.” The technique is inherently interdisciplinary, because in addition to those archeologists and paleobiologists wishing to apply it, most applications require informed input from ecologists, geochemists, and calcified tissue biologists. This perspective explores how such interdisciplinarity is both a strength and an impediment to further advancement.

Anthropological genetics perspectives on the transatlantic slave trade

During the Trans-Atlantic Slave Trade (TAST), around twelve million Africans were enslaved and forcibly moved from Africa to the Americas and Europe, durably influencing the genetic and cultural landscape of a large part of humanity since the 15th century. Following historians, archaeologists, and anthropologists, population geneticists have, since the 1950's mainly, extensively investigated the genetic diversity of populations on both sides of the Atlantic. These studies shed new lights into the largely unknown genetic origins of numerous enslaved-African descendant communities in the Americas, by inferring their genetic relationships with extant African, European, and Native American populations. Furthermore, exploring genome-wide data with novel statistical and bioinformatics methods, population geneticists have been increasingly able to infer the last 500 years of admixture histories of these populations. These inferences have highlighted the diversity of histories experienced by enslaved-African descendants, and the complex influences of socioeconomic, political, and historical contexts on human genetic diversity patterns during and after the slave trade. Finally, the recent advances of paleogenomics unveiled crucial aspects of the life and health of the first generation of enslaved-Africans in the Americas. Altogether, human population genetics approaches in the genomic and paleogenomic era need to be coupled with history, archaeology, anthropology, and demography in interdisciplinary research, to reconstruct the multifaceted and largely unknown history of the TAST and its influence on human biological and cultural diversities today. Here, we review anthropological genomics studies published over the past 15 years and focusing on the history of enslaved-African descendant populations in the Americas.

Ancestry, health, and lived experiences of enslaved Africans in 18th century Charleston: An osteobiographical analysis

OBJECTIVES

In 2013, the burials of 36 individuals of putative African ancestry were discovered during renovation of the Gaillard Center in downtown Charleston, South Carolina. The Charleston community facilitated a bioarchaeological and mitogenomic study to gain insights into the lives of these unknown persons, referred to as the Anson Street Ancestors, including their ancestry, health, and lived experiences in the 18th century.

METHODS

Metric and morphological assessments of skeletal and dental characteristics were recorded, and enamel and cortical bone strontium stable isotope values generated. Whole mitochondrial genomes were sequenced and analyzed.

RESULTS

Osteological analysis identified adults, both females and males, and subadults at the site, and estimated African ancestry for most individuals. Skeletal trauma and pathology were infrequent, but many individuals exhibited dental decay and abscesses. Strontium isotope data suggested these individuals mostly originated in Charleston or sub-Saharan Africa, with many being long-term residents of Charleston. Nearly all had mitochondrial lineages belonging to African haplogroups (L0-L3, H1cb1a), with two individuals sharing the same L3e2a haplotype, while one had a Native American A2 mtDNA.

DISCUSSION

This study generated detailed osteobiographies of the Anson Street Ancestors, who were likely of enslaved status. Our results indicate that the Ancestors have diverse maternal African ancestries and are largely unrelated, with most being born locally. These details reveal the demographic impact of the trans-Atlantic slave trade. Our analysis further illuminates the lived experiences of individuals buried at Anson Street, and expands our understanding of 18th century African history in Charleston.

Origin and Health Status of First-Generation Africans from Early Colonial Mexico

The forced relocation of several thousand Africans during Mexico's historic period has so far been documented mostly through archival sources, which provide only sparse detail on their origins and lived experience. Here, we employ a bioarchaeological approach to explore the life history of three 16^th century Africans from a mass burial at the San José de los Naturales Royal Hospital in Mexico City. Our approach draws together ancient genomic data, osteological analysis, strontium isotope data from tooth enamel, δ¹³C and δ¹⁵N isotope data from dentine, and ethnohistorical information to reveal unprecedented detail on their origins and health. Analyses of skeletal features, radiogenic isotopes, and genetic data from uniparental, genome-wide, and human leukocyte antigen (HLA) markers are consistent with a Sub-Saharan African origin for all three individuals. Complete genomes of Treponema pallidum sub. pertenue (causative agent of yaws) and hepatitis B virus (HBV) recovered from these individuals provide insight into their health as related to infectious disease. Phylogenetic analysis of both pathogens reveals their close relationship to strains circulating in current West African populations, lending support to their origins in this region. The further relationship between the treponemal genome retrieved and a treponemal genome previously typed in an individual from Colonial Mexico highlights the role of the transatlantic slave trade in the introduction and dissemination of pathogens into the New World. Putting together all lines of evidence, we were able to create a biological portrait of three individuals whose life stories have long been silenced by disreputable historical events.

Isotopic evidence for anthropogenic lead exposure on a 17th/18th century Barbadian plantation

OBJECTIVES

To identify and characterize anthropogenic lead sources on a 17th/18th century Barbadian plantation and to test if lead isotope analyses can be used to identify the geographic origins of first-generation African captives.

MATERIALS AND METHODS

We carried out lead (Pb) isotope analyses on dental enamel samples from 24 individuals from the Newton Plantation Cemetery in Barbados, which had previously been analyzed for strontium (Sr) and oxygen (O) isotope composition (Schroeder et al., American Journal of Physical Anthropology, 2009, 139:547-557) and Pb concentrations (Schroeder et al., American Journal of Physical Anthropology, 2013, 150:203-209.

RESULTS

We are able to identify British Pb sources, and more specifically Bristol/Mendips Pb, as the most likely source of anthropogenic Pb on the plantation, highlighting the impact of the British Atlantic economy on the lives of enslaved peoples in Barbados during the period of plantation slavery. Furthermore, we find that there is only one clear outlier among seven individuals who had previously been identified as African-born based on their enamel Sr isotope composition (Schroeder et al., American Journal of Physical Anthropology, 2009, 139:547-557). All other individuals present a very homogenous Pb isotope composition, which overlaps with that of British Pb sources.

CONCLUSION

Our results indicate that while Pb isotope analyses can help identify and further characterize the sources of anthropogenic Pb in plantation settings, they might not be suited for identifying the origins of African-born individuals in diasporic contexts.

Flows of people in villages and large centres in Bronze Age Italy through strontium and oxygen isotopes

This study investigates to what extent Bronze Age societies in Northern Italy were permeable accepting and integrating non-local individuals, as well as importing a wide range of raw materials, commodities, and ideas from networks spanning continental Europe and the Mediterranean. During the second millennium BC, the communities of Northern Italy engaged in a progressive stabilization of settlements, culminating in the large polities of the end of the Middle/beginning of the Late Bronze Age pivoted around large defended centres (the Terramare). Although a wide range of exotic archaeological materials indicates that the inhabitants of the Po plain increasingly took part in the networks of Continental European and the Eastern Mediterranean, we should not overlook the fact that the dynamics of interaction were also extremely active on local and regional levels. Mobility patterns have been explored for three key-sites, spanning the Early to Late Bronze Age (1900-1100 BC), namely Sant'Eurosia, Casinalbo and Fondo Paviani, through strontium and oxygen isotope analysis on a large sample size (more than 100 individuals). The results, integrated with osteological and archaeological data, document for the first time in this area that movements of people occurred mostly within a territorial radius of 50 km, but also that larger nodes in the settlement system (such as Fondo Paviani) included individuals from more distant areas. This suggests that, from a demographic perspective, the process towards a more complex socio-political system in Bronze Age Northern Italy was triggered by a largely, but not completely, internal process, stemming from the dynamics of intra-polity networks and local/regional power relationships.

Tracking natural and anthropogenic Pb exposure to its geological source

Human Pb exposure comes from two sources: (i) natural uptake through ingestion of soils and typified by populations that predate mining activity and (ii) anthropogenic exposure caused by the exposure to Pb derived from ore deposits. Currently, the measured concentration of Pb within a sample is used to discriminate between these two exposure routes, with the upper limit for natural exposure in skeletal studies given as 0.5 or 0.7 mg/kg in enamel and 0.5/0.7 μg/dL in blood. This threshold approach to categorising Pb exposure does not distinguish between the geological origins of the exposure types. However, Pb isotopes potentially provide a more definitive means of discriminating between sources. Whereas Pb from soil displays a crustal average ²³⁸U/²⁰⁴Pb (μ) value of c 9.7, Pb from ore displays a much wider range of evolution pathways. These characteristics are transferred into tooth enamel, making it possible to characterize human Pb exposure in terms of the primary source of ingested Pb and to relate mining activity to geotectonic domains. We surmise that this ability to discriminate between silicate and sulphide Pb exposure will lead to a better understanding of the evolution of early human mining activity and development of exposure models through the Anthropocene.

Breastfeeding, weaning, and dietary practices during the Western Zhou Dynasty (1122-771 BC) at Boyangcheng, Anhui Province, China

OBJECTIVES

Here we investigate breastfeeding and weaning practices and adult dietary habits at the Western Zhou Dynasty (1122-771 BC) site of Boyangcheng () located in Anhui Province, China. In addition, we utilize the differences in bone collagen turnover rates between rib and long bones from the same individual to examine past life histories, such as changes in diet or residence.

MATERIALS AND METHODS

Bone collagen from both the rib and long bones (either femora or humeri) of 42 individuals was measured for stable isotope ratios of carbon (δ¹³ C) and nitrogen (δ¹⁵ N). In addition, δ¹³ C and δ¹⁵ N values are reported for 35 animals (dogs, cows, horses, pigs, and deer).

RESULTS

The human δ¹³ C values range from -20.7‰ to -12.0‰ with a mean value of -18.8 ± 1.6‰. The human δ¹⁵ N values range from 9.1‰ to 13.4‰ with a mean value of 10.9 ± 1.0‰. The animals display a wide range of δ¹³ C (-21.5‰ to -8.2‰; -15.8 ± 4.5‰) and δ¹⁵ N values (4.0‰ to 9.5‰; 6.5 ± 1.8‰).

CONCLUSIONS

The adult δ¹³ C and δ¹⁵ N results indicate that mixed C₃ (rice) and C₄ (millet) terrestrial diets with varying levels of animal protein (mostly pigs and deer) were consumed. The elevated subadult δ¹⁵ N results return to adult levels by approximately 3-4 years of age, indicating that the weaning process was completed during this period. Individuals between 2 and 10 years old, with lower δ¹³ C and δ¹⁵ N results than the adult mean, possibly consumed more plant-based diets, and this is consistent with Chinese medical teachings ∼1500 years later during the Tang Dynasty (AD 618-907). The isotopic offsets between the ribs and long bones revealed that five adults experienced dramatic dietary shifts in their later lives, switching from predominately C₃ /C₄ to C₃ diets. This research provides the first isotopic information about ancient Chinese breastfeeding and weaning practices and establishes a foundation for future studies to examine diachronic trends.

Practising pastoralism in an agricultural environment: An isotopic analysis of the impact of the Hunnic incursions on Pannonian populations

We conducted a multi-isotope study of five fifth-century AD cemeteries in modern-day Hungary to determine relationships between nomadic-pastoralist incomers—the historically documented Huns and other nomadic groups—and the sedentary agricultural population of the late Roman province of Pannonia. Contemporary historical sources describe this relationship as adversarial and destructive for the late Roman population, but archaeological evidence indicates high levels of hybridity between different groups. We undertook carbon, nitrogen, strontium and oxygen isotope analyses of bone collagen, dentine and tooth enamel at Keszthely-Fenékpuszta, Hács-Béndekpuszta, Győr-Széchenyi Square, Mözs and Szolnok-Szanda to examine these relationships through past subsistence practices. The patterns at all sites indicate medium to high animal protein consumption with little evidence for a significant contribution of aquatic resources. All populations relied to a great extent on C4 plants, most likely millet. Within each population, diet was heterogeneous, with significant variations in terms of animal protein and C3 and C4 plant consumption. High levels of intra-population and individual variability suggest that populations made use of a range of subsistence strategies, with many individuals exhibiting significant changes over their lifetimes. Rather than being characterised only by violence, the historically-documented influx of nomadic populations appears to have led to widespread changes in subsistence strategies of populations in the Carpathian basin. Nomadic-pastoralist groups may have switched to smaller herds and more farming, and, conversely, local populations may have integrated with a new economic system based on animal herding.

Dynamics of Indian Ocean Slavery Revealed through Isotopic Data from the Colonial Era Cobern Street Burial Site, Cape Town, South Africa (1750-1827)

The Dutch East India Company (VOC) intended the Cape of Good Hope to be a refreshment stop for ships travelling between the Netherlands and its eastern colonies. The indigenous Khoisan, however, did not constitute an adequate workforce, therefore the VOC imported slaves from East Africa, Madagascar and Asia to expand the workforce. Cape Town became a cosmopolitan settlement with different categories of people, amongst them a non-European underclass that consisted of slaves, exiles, convicts and free-blacks. This study integrated new strontium isotope data with carbon and nitrogen isotope results from an 18th-19th century burial ground at Cobern Street, Cape Town, to identify non-European forced migrants to the Cape. The aim of the study was to elucidate individual mobility patterns, the age at which the forced migration took place and, if possible, geographical provenance. Using three proxies, 87Sr/86Sr, δ13Cdentine and the presence of dental modifications, a majority (54.5%) of the individuals were found to be born non-locally. In addition, the 87Sr/86Sr data suggested that the non-locally born men came from more diverse geographic origins than the migrant women. Possible provenances were suggested for two individuals. These results contribute to an improved understanding of the dynamics of slave trading in the Indian Ocean world.

Subadult dietary variation at Trino Vercellese, Italy, and its relationship to adult diet and mortality

OBJECTIVES

Early-life nutrition is a predisposing factor for later-life outcomes. This study tests the hypothesis that subadults from medieval Trino Vercellese, Italy, who lived to adulthood consumed isotopically different diets compared with subadults who died before reaching adulthood. We have previously used a life history approach, comparing dentine and bone of the same adult individuals ("subadults who lived"), to elucidate dietary variation across the life span. Here, we examine diets of "subadults who died" from the same population, estimated from subadult rib collagen, to explore whether dietary behaviors of subadults who lived differed from those of subadults who died.

METHODS

Forty-one subadults aged six months to 14.5 years were studied through stable carbon and nitrogen isotope analysis of collagen.

RESULTS

Individuals were weaned by age 4 years, with considerable variation in weaning ages overall. Post-weaning, diets of subadults who died comprised significantly less animal protein than diets of subadults who lived. Isotopic values of the two oldest individuals, 13.5 and 14.5 years, show the same status-based variation in diet as do adults from the population.

CONCLUSIONS

Our results suggest that incorporating animal protein in diet during growth and development supported medieval subadults' ability to survive to adulthood. Isotopic similarities between adults and older subadults suggest "adult" dietary behaviors were adopted in adolescence. Stable isotope evidence from subadults bridges a disparity between ontogenetic age categories and socioculturally meaningful age categories in the past, and sheds light on the underpinnings of health, mortality, growth, and disease in the bioarchaeological record. Am J Phys Anthropol 160:653-664, 2016. © 2016 Wiley Periodicals, Inc.

All Roads Lead to Rome: Exploring Human Migration to the Eternal City through Biochemistry of Skeletons from Two Imperial-Era Cemeteries (1st-3rd c AD)

Migration within the Roman Empire occurred at multiple scales and was engaged in both voluntarily and involuntarily. Because of the lengthy tradition of classical studies, bioarchaeological analyses must be fully contextualized within the bounds of history, material culture, and epigraphy. In order to assess migration to Rome within an updated contextual framework, strontium isotope analysis was performed on 105 individuals from two cemeteries associated with Imperial Rome—Casal Bertone and Castellaccio Europarco—and oxygen and carbon isotope analyses were performed on a subset of 55 individuals. Statistical analysis and comparisons with expected local ranges found several outliers who likely immigrated to Rome from elsewhere. Demographics of the immigrants show men and children migrated, and a comparison of carbon isotopes from teeth and bone samples suggests the immigrants may have significantly changed their diet. These data represent the first physical evidence of individual migrants to Imperial Rome. This case study demonstrates the importance of employing bioarchaeology to generate a deeper understanding of a complex ancient urban center.

Isotopic evidence of human mobility and diet in a prehistoric/protohistoric Fijian coastal environment (c. 750-150 BP)

OBJECTIVES

Bourewa, on the southwest coast of Viti Levu in Fiji, is a multi-period site that contained burials dated to the later Vuda Phase (750-150 BP), a period of climatic fluctuations that potentially impacted the availability of food resources. We aim to investigate diet and movement at this site during a time of possible ecological pressure and political change.

MATERIALS AND METHODS

We analyzed δ(13) C, δ(15) N, and (87) Sr/(86) Sr of these Vuda Phase individuals (n = 25) interred at the site. By analyzing dentin and bone, both childhood diet and the diet within the past few years of adults' lives were examined.

RESULTS

The paleodietary results suggested that adult diets consisted largely of low trophic level marine organisms. Dentin and bone isotopic values differed significantly: childhood diet involved consumption of more higher trophic level terrestrial foods. Most individuals displayed (87) Sr/(86) Sr ratios expected of people living along a marine coastline. However, a few individuals displayed (87) Sr/(86) Sr ratios and paleodietary values (δ(13) Cdentin , δ(15) Ndentin ) suggestive of living further inland or consuming a more terrestrial-based childhood diet.

DISCUSSION

The results are compared with past studies of sites from Fiji and nearby archipelagoes, placing our interpretations into a wider regional context. The Bourewa community appears to have consumed more low trophic level marine foods than any nearby site, possibly because terrestrial foods were more difficult to acquire. Interpreting the childhood diet is challenging due to the paucity of ethnohistoric literature on Fijian childhood; small meals outside of communal mealtimes or feeding children terrestrial animal protein as a means of cultural buffering are potential explanations.

The peopling of the African continent and the diaspora into the new world

Africa is the birthplace of anatomically modern humans, and is the geographic origin of human migration across the globe within the last 100,000 years. The history of African populations has consisted of a number of demographic events that have influenced patterns of genetic and phenotypic variation across the continent. With the increasing amount of genomic data and corresponding developments in computational methods, researchers are able to explore long-standing evolutionary questions, expanding our understanding of human history within and outside of Africa. This review will summarize some of the recent findings regarding African demographic history, including the African Diaspora, and will briefly explore their implications for disease susceptibility in populations of African descent.

Using isotopic evidence to assess the impact of migration and the two-layer hypothesis in prehistoric Northeast Thailand

OBJECTIVES

The nature of the agricultural transition in Southeast Asia has been a topic of some debate for archaeologists over the past decades. A prominent model, known as the two-layer hypothesis, states that indigenous hunter-gatherers were subsumed by the expansion of exotic Neolithic farmers into the area around 2000 BC. These farmers had ultimate origins in East Asia and brought rice and millet agriculture. Ban Non Wat is one of the few archaeological sites in Southeast Asia where this model can potentially be tested. The site is located in the Mun River valley of Northeast Thailand, and divided into 12 phases that span over 2,000 years, from about 1750 BC to the end of the Iron Age (ca. 500 AD). These phases exhibit successive cultural changes, and current interpretation of the site is of an early hunter-gatherer population, with agriculturalists immigrating into the later phases.

METHODS

We analyzed strontium, oxygen, and carbon isotopes in tooth enamel from over 150 individuals, dating from the Neolithic to Iron Age, to assess extrinsic origins and differences in diet between early and later phases.

RESULTS

We find evidence of dietary and cultural differences between groups at Ban Non Wat during its early occupation, but little evidence for immigration from distinct environments beyond the Khorat Plateau of Northeast Thailand.

CONCLUSIONS

The lack of consistent isotopic differences between early and later Neolithic occupants at Ban Non Wat means that the site does not conclusively support the two-layer hypothesis.

Stable isotope biogeochemistry of seabird guano fertilization: results from growth chamber studies with maize (Zea mays)

BACKGROUND

Stable isotope analysis is being utilized with increasing regularity to examine a wide range of issues (diet, habitat use, migration) in ecology, geology, archaeology, and related disciplines. A crucial component to these studies is a thorough understanding of the range and causes of baseline isotopic variation, which is relatively poorly understood for nitrogen (δ(15)N). Animal excrement is known to impact plant δ(15)N values, but the effects of seabird guano have not been systematically studied from an agricultural or horticultural standpoint.

METHODOLOGY/PRINCIPAL FINDINGS

This paper presents isotopic (δ(13)C and δ(15)N) and vital data for maize (Zea mays) fertilized with Peruvian seabird guano under controlled conditions. The level of (15)N enrichment in fertilized plants is very large, with δ(15)N values ranging between 25.5 and 44.7‰ depending on the tissue and amount of fertilizer applied; comparatively, control plant δ(15)N values ranged between -0.3 and 5.7‰. Intraplant and temporal variability in δ(15)N values were large, particularly for the guano-fertilized plants, which can be attributed to changes in the availability of guano-derived N over time, and the reliance of stored vs. absorbed N. Plant δ(13)C values were not significantly impacted by guano fertilization. High concentrations of seabird guano inhibited maize germination and maize growth. Moreover, high levels of seabird guano greatly impacted the N metabolism of the plants, resulting in significantly higher tissue N content, particularly in the stalk.

CONCLUSIONS/SIGNIFICANCE

The results presented in this study demonstrate the very large impact of seabird guano on maize δ(15)N values. The use of seabird guano as a fertilizer can thus be traced using stable isotope analysis in food chemistry applications (certification of organic inputs). Furthermore, the fertilization of maize with seabird guano creates an isotopic signature very similar to a high-trophic level marine resource, which must be considered when interpreting isotopic data from archaeological material.

The men of Nelson's navy: a comparative stable isotope dietary study of late 18th century and early 19th century servicemen from Royal Naval Hospital burial grounds at Plymouth and Gosport, England

We present stable isotopic analyses of collagen from 80 servicemen excavated from the late 18th/early 19th century naval hospitals at Plymouth (50) and Haslar, Gosport (30) in southern England. Historical records suggest that, the diets of these two populations should be essentially identical. While δ(15) N of the rib collagen confirmed that naval servicemen were relatively well-catered for in terms of meat allowance (Plymouth average δ(15) N = 11.1‰, Gosport = 11.9‰), stable carbon isotope analysis produced average values for the two assemblages, which were significantly different (Plymouth average δ(13) C = -18.8‰, Gosport = -20.0‰). We postulate that these differences stem from divergent naval postings, with a greater proportion of Plymouth individuals serving in areas that entailed a greater input of C(4) foodstuffs. By comparison with published data from approximately contemporary burials at Snake Hill, Ontario, Canada and Chesapeake Bay, Virginia, we suggest that this area is the east coast of North America. For 15 of the 30 individuals from Gosport, we have data on ribs, femur, and dentine from the same skeleton, which appear to show that they came from a variety of locations in their preadolescence, but converged in dietary terms onto a "naval average," which is consistent with historical evidence for recruitment patterns into the Navy at the time. By comparison with published data from skeletons recovered from the wreck of the Mary Rose (sank 1545), we conclude that this naval diet was virtually unchanged from the 16th century to the end of the 18th century.

Passports from the past: Investigating human dispersals using strontium isotope analysis of tooth enamel

Strontium isotopes are a powerful tool which provide information about provenance directly from the tissues of humans rather than the grave context and burial goods. Geographical variation in strontium isotopes is primarily controlled by the underlying geology but there are many other factors that need to be considered before migratory individuals can be identified. Consequently, despite many studies which have shown that the method works well, it is clear that much remains to be clarified and it will not work for every question or in every place. It rests on the assumption that people were sourcing their food locally and that there is a measurable strontium isotope difference between the place the person migrated from and the place they migrated to. As migrants may deliberately seek out familiar soil types and terrains in their new homeland, some questions surrounding major migration events may prove intractable for this technique. Other factors that can create heterogeneity or homogeneity leading to false positives or false negatives, such as human choices or coastal subsistence, are explored and the metabolism of strontium into human tooth enamel is discussed. Several models of land-use choices by humans are presented to highlight the subtleties inherent in the isotope data and these are used to interpret archaeological human isotope ratios from three studies.