Animal movement on the hoof and on the cart and its implications for understanding exchange within the Indus Civilisation

Movement of resources was essential to the survival and success of early complex societies. The sources and destinations of goods and the means of transportation - be it by boats, carts and/or foot - can often be inferred, but the logistics of these movements are inherently more difficult to ascertain. Here, we use strontium isotopic analysis to test hypotheses about the role of animal and animal-powered transport in medium and long-distance movement and exchange, using the Indus Civilization as a case study. Across the wide geographical spread of the Indus Civilisation, there is strong evidence for long-distance exchange of raw materials and finished objects and this process is presumed to involve boats and animal-driven transport, although there is little evidence as to the relative importance of each mode of movement. Strontium isotopic analysis of animal remains from four sites analysed for this study combined with results from nine other sites indicates limited long-distance animal movement between different geological zones within the Indus Civilisation. These findings suggest that individual animals primarily moved short- or medium-distances, though there are several significant exceptions seen in some pigs and cattle found at two large urban sites. We infer that long-distance transport of goods, be it raw materials, finished objects, other goods, or the animals themselves, could have occurred through the use of boats and waterways, by traction animals moving over long distances that did not end up in the archaeological record, and/or by different animals participating in many short to medium-distance movements.

Isotope data from amino acids indicate Darwin's ground sloth was not an herbivore

Fossil sloths are regarded as obligate herbivores for reasons including peculiarities of their craniodental morphology and that all living sloths feed exclusively on plants. We challenge this view based on isotopic analyses of nitrogen of specific amino acids, which show that Darwin's ground sloth Mylodon darwinii was an opportunistic omnivore. This direct evidence of omnivory in an ancient sloth requires reevaluation of the ecological structure of South American Cenozoic mammalian communities, as sloths represented a major component of these ecosystems across the past 34 Myr. Furthermore, by analyzing modern mammals with known diets, we provide a basis for reliable interpretation of nitrogen isotopes of amino acids of fossils. We argue that a widely used equation to determine trophic position is unnecessary, and that the relative isotopic values of the amino acids glutamate and phenylalanine alone permit reliable reconstructions of trophic positions of extant and extinct mammals.

Lipid residues in pottery from the Indus Civilisation in northwest India

This paper presents novel insights into the archaeology of food in ancient South Asia by using lipid residue analysis to investigate what kinds of foodstuffs were used in ceramic vessels by populations of the Indus Civilisation in northwest India. It examines how vessels were used in urban and rural Indus settlements during the Mature Harappan period (c.2600/2500-1900 BC), the relationship between vessels and the products within them, and identifies whether changes in vessel use occurred from the Mature Harappan to Late Harappan periods, particularly during climatic instability after 4.2 ka BP (c.2100 BC). Despite low lipid concentrations, which highlight challenges with conducting residue analysis in arid, seasonally-wet and alkaline environments, 71% of the vessels yielded appreciable quantities of lipid. Lipid profiles revealed the use of animal fats in vessels, and contradictory to faunal evidence, a dominance of non-ruminant fats, with limited evidence of dairy processing. The absence of local modern reference fats makes this dataset challenging to interpret, and it is possible that plant products or mixtures of plant and animal products have led to ambiguous fatty acid-specific isotopic values. At the same time, it appears that urban and rural populations processed similar types of products in vessels, with limited evidence for change in vessel use from the urban to the post-urban period. This study is a systematic investigation into pot lipid residues from multiple sites, demonstrating the potential of the method for examining ancient Indus foodways and the need for the development of further research in ancient organic residues in South Asia.

Carbon and nitrogen isotopic variability in foxtail millet (Setaria italica) with watering regime

RATIONALE

Carbonised plant remains are analysed for reconstruction of past climates and agricultural regimes. Several recent studies have used C4 plants to address related questions, and correlations between modern C4 plant δ13 C values and rainfall have been found. The millets were important food crops in prehistoric Eurasia, yet little is known about causes of isotopic variation within millet species. Previous research has shown there to be significant isotopic variation between millet accessions. Here we compare isotope ratios from plants grown under different watering regimes. This allows for a consideration of whether or not Setaria italica is a good proxy for environmental reconstruction.

METHODS

We compare stable isotope ratios of Setaria italica plants grown in a controlled environment chamber with different watering regimes. We compare the carbon isotope ratios of leaves and grains, and the nitrogen isotope ratios of grains, from 12 accessions of Setaria italica.

RESULTS

We find significant isotopic variability between watering regimes. Carbon isotope ratios are positively correlated with water availability, and on average vary by 1.9‰ and 1.7‰ for leaves and grains, respectively. Grain nitrogen isotope ratios also vary with watering regime; however, the highest isotope ratios are found with the 130-mL watering regime.

CONCLUSIONS

The carbon isotope ratios of Setaria italica are strongly correlated with water availability. However, the correlation is the opposite to that seen in studies of C3 plants. The difference in isotopic ratio due to watering regime is comparable with that seen between different accessions; thus distinguishing between changing varieties of Setaria italica and changing climate is problematic. In terms of grain nitrogen isotope ratios, the highest δ15 N values were not associated with the lowest watering regime. Again, δ15 N variation is comparable with that which would be expected from an aridity effect or a manuring effect, and thus distinguishing between these factors is probably problematic.

Carbon and nitrogen isotopic signatures of hair, nail, and breath from tropical African human populations

RATIONALE

Stable isotopic analyses are increasingly used to study the diets of past and present human populations. Yet, the carbon and nitrogen isotopic data of modern human diets collected so far are biased towards Europe and North America. Here, we address this gap by reporting on the dietary isotopic signatures of six tropical African communities: El Molo, Turkana (Kerio), Luhya (Webuye), Luhya (Port Victoria), and Luo (Port Victoria) from Kenya, and Baka from Cameroon; representing four subsistence strategies: fishing, pastoralism, agriculturalism, and hunter-gatherer.

METHODS

We used an elemental analyser coupled in continuous-flow mode to an isotope ratio mass spectrometer to measure the carbon and nitrogen isotopic ratios of hair (n = 134) and nail (n = 80) and the carbon isotopic ratios of breath (n = 184) from these communities, as well as the carbon and nitrogen isotopic ratios of some food samples from the Kenyan communities.

RESULTS

We expand on the known range of δ¹³ C values in human hair through the hunter-gatherer Baka, with a diet based on C₃ plants, and through the agriculturalist Luhya (Webuye), with a diet based on C₄ plants. In addition, we found that the consumption of fish from East African lakes is difficult to detect isotopically due to the combined effects of high nitrogen isotopic ratios of plants and the low nitrogen isotopic ratios of fish. Finally, we found that some of the communities studied are markedly changing their diets through increasing sedentism and urbanisation.

CONCLUSIONS

Our findings contribute substantially to the understanding of the environmental, demographic, and economic dynamics that affect the dietary landscape of different tropical populations of Africa. These results highlight the importance of studying a broader sample of human populations and their diet, with a focus on their precise context - from both isotopic and more general anthropological perspectives.

East Anglian early Neolithic monument burial linked to contemporary Megaliths

In the fourth millennium BCE a cultural phenomenon of monumental burial structures spread along the Atlantic façade. Megalithic burials have been targeted for aDNA analyses, but a gap remains in East Anglia, where Neolithic structures were generally earthen or timber. An early Neolithic (3762–3648 cal. BCE) burial monument at the site of Trumpington Meadows, Cambridgeshire, UK, contained the partially articulated remains of at least three individuals. To determine whether this monument fits a pattern present in megalithic burials regarding sex bias, kinship, diet and relationship to modern populations, teeth and ribs were analysed for DNA and carbon and nitrogen isotopic values, respectively. Whole ancient genomes were sequenced from two individuals to a mean genomic coverage of 1.6 and 1.2X and genotypes imputed. Results show that they were brothers from a small population genetically and isotopically similar to previously published British Neolithic individuals, with a level of genome-wide homozygosity consistent with a small island population sourced from continental Europe, but bearing no signs of recent inbreeding. The first Neolithic whole genomes from a monumental burial in East Anglia confirm that this region was connected with the larger pattern of Neolithic megaliths in the British Isles and the Atlantic façade.

Ancient human parallel lineages within North America contributed to a coastal expansion

Little is known regarding the first people to enter the Americas and their genetic legacy. Genomic analysis of the oldest human remains from the Americas showed a direct relationship between a Clovis-related ancestral population and all modern Central and South Americans as well as a deep split separating them from North Americans in Canada. We present 91 ancient human genomes from California and Southwestern Ontario and demonstrate the existence of two distinct ancestries in North America, which possibly split south of the ice sheets. A contribution from both of these ancestral populations is found in all modern Central and South Americans. The proportions of these two ancestries in ancient and modern populations are consistent with a coastal dispersal and multiple admixture events.

'Trophic' and 'source' amino acids in trophic estimation: a likely metabolic explanation

Amino acid nitrogen isotopic analysis is a relatively new method for estimating trophic position. It uses the isotopic difference between an individual's 'trophic' and 'source' amino acids to determine its trophic position. So far, there is no accepted explanation for the mechanism by which the isotopic signals in 'trophic' and 'source' amino acids arise. Yet without a metabolic understanding, the utility of nitrogen isotopic analyses as a method for probing trophic relations, at either bulk tissue or amino acid level, is limited. I draw on isotopic tracer studies of protein metabolism, together with a consideration of amino acid metabolic pathways, to suggest that the 'trophic'/'source' groupings have a fundamental metabolic origin, to do with the cycling of amino-nitrogen between amino acids. 'Trophic' amino acids are those whose amino-nitrogens are interchangeable, part of a metabolic amino-nitrogen pool, and 'source' amino acids are those whose amino-nitrogens are not interchangeable with the metabolic pool. Nitrogen isotopic values of 'trophic' amino acids will reflect an averaged isotopic signal of all such dietary amino acids, offset by the integrated effect of isotopic fractionation from nitrogen cycling, and modulated by metabolic and physiological effects. Isotopic values of 'source' amino acids will be more closely linked to those of equivalent dietary amino acids, but also modulated by metabolism and physiology. The complexity of nitrogen cycling suggests that a single identifiable value for 'trophic discrimination factors' is unlikely to exist. Greater consideration of physiology and metabolism should help in better understanding observed patterns in nitrogen isotopic values.

Red deer bone and antler collagen are not isotopically equivalent in carbon and nitrogen

RATIONALE

Bone and antler collagen δ(13) C and δ(15) N values are often assumed to be equivalent when measured in palaeodietary, palaeoclimate and palaeocological studies. Although compositionally similar, bone grows slowly and is remodelled whereas antler growth is rapid and remodelling does not occur. These different patterns of growth could result in isotopic difference within antler and between the two tissue types. Here we test whether red deer (Cervus elaphus) bone and antler δ(13) C and δ(15) N values are equivalent, and whether intra-antler isotopic values are uniform.

METHODS

Bone and antler were isotopically analysed from six stags that lived in a temperate maritime climate on the Isle of Rum, Scotland. Multiple antlers from different years were sampled per individual, together with a single bone sample per individual. Up to 12 samples were taken along the length of each antler (total of 25 antlers, 259 samples) so that a chronological record of the isotopic composition during antler growth could be obtained. Collagen was extracted and its δ(13) C and δ(15) N values were measured by continuous-flow isotope ratio mass spectrometry.

RESULTS

Intra-antler collagen isotope signatures vary, and show that not all antlers from an individual or a growth year are equivalent in carbon and nitrogen isotopic ratios. δ(15) N values typically increase with distance along antler length, but no overall trend is observed in δ(13) C values. An isotopic offset is visible between bone and antler, with bone δ(13) C and δ(15) N values being higher in most cases.

CONCLUSIONS

Bone and antler collagen δ(13) C and δ(15) N values are not isotopically equivalent and are therefore not directly comparable in palaeodietary, palaeoclimate and palaeocological studies. Bone and antler collagen isotopic differences probably relate to differential metabolic processes during the formation of the two tissues. Intra- and inter-antler isotopic variations probably reflect the isotopic composition of an individual's diet rather than physiological parameters, and may have the potential to provide high-resolution individual-specific information in modern and ancient cervid populations. Copyright © 2016 John Wiley & Sons, Ltd.

The globalization of naval provisioning: ancient DNA and stable isotope analyses of stored cod from the wreck of the Mary Rose, AD 1545

A comparison of ancient DNA (single-nucleotide polymorphisms) and carbon and nitrogen stable isotope evidence suggests that stored cod provisions recovered from the wreck of the Tudor warship Mary Rose, which sank in the Solent, southern England, in 1545, had been caught in northern and transatlantic waters such as the northern North Sea and the fishing grounds of Iceland and Newfoundland. This discovery, underpinned by control data from archaeological samples of cod bones from potential source regions, illuminates the role of naval provisioning in the early development of extensive sea fisheries, with their long-term economic and ecological impacts.

Serum carbon and nitrogen stable isotopes as potential biomarkers of dietary intake and their relation with incident type 2 diabetes: the EPIC-Norfolk study

BACKGROUND

Stable-isotope ratios of carbon (¹³C/¹²C, expressed as δ¹³C) and nitrogen (¹⁵N/¹⁴N, or δ¹⁵N) have been proposed as potential nutritional biomarkers to distinguish between meat, fish, and plant-based foods.

OBJECTIVE

The objective was to investigate dietary correlates of δ¹³C and δ¹⁵N and examine the association of these biomarkers with incident type 2 diabetes in a prospective study.

DESIGN

Serum δ¹³C and δ¹⁵N (‰) were measured by using isotope ratio mass spectrometry in a case-cohort study (n = 476 diabetes cases; n = 718 subcohort) nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk population-based cohort. We examined dietary (food-frequency questionnaire) correlates of δ¹³C and δ¹⁵N in the subcohort. HRs and 95% CIs were estimated by using Prentice-weighted Cox regression.

RESULTS

Mean (±SD) δ¹³C and δ¹⁵N were -22.8 ± 0.4‰ and 10.2 ± 0.4‰, respectively, and δ¹³C (r = 0.22) and δ¹⁵N (r = 0.20) were positively correlated (P < 0.001) with fish protein intake. Animal protein was not correlated with δ¹³C but was significantly correlated with δ¹⁵N (dairy protein: r = 0.11; meat protein: r = 0.09; terrestrial animal protein: r = 0.12, P ≤ 0.013). δ¹³C was inversely associated with diabetes in adjusted analyses (HR per tertile: 0.74; 95% CI: 0.65, 0.83; P-trend < 0.001], whereas δ¹⁵N was positively associated (HR: 1.23; 95% CI: 1.09, 1.38; P-trend = 0.001).

CONCLUSIONS

The isotope ratios δ¹³C and δ¹⁵N may both serve as potential biomarkers of fish protein intake, whereas only δ¹⁵N may reflect broader animal-source protein intake in a European population. The inverse association of δ¹³C but a positive association of δ¹⁵N with incident diabetes should be interpreted in the light of knowledge of dietary intake and may assist in identifying dietary components that are associated with health risks and benefits.

Water consumption in Iron Age, Roman, and Early Medieval Croatia

Patterns of water consumption by past human populations are rarely considered, yet drinking behavior is socially mediated and access to water sources is often socially controlled. Oxygen isotope analysis of archeological human remains is commonly used to identify migrants in the archeological record, but it can also be used to consider water itself, as this technique documents water consumption rather than migration directly. Here, we report an oxygen isotope study of humans and animals from coastal regions of Croatia in the Iron Age, Roman, and Early Medieval periods. The results show that while faunal values have little diachronic variation, the human data vary through time, and there are wide ranges of values within each period. Our interpretation is that this is not solely a result of mobility, but that human behavior can and did lead to human oxygen isotope ratios that are different from that expected from consumption of local precipitation.

Carbon and nitrogen isotopic ratios of urine and faeces as novel nutritional biomarkers of meat and fish intake

PURPOSE

Meat and fish consumption are associated with changes in the risk of chronic diseases. Intake is mainly assessed using self-reporting, as no true quantitative nutritional biomarker is available. The measurement of plasma fatty acids, often used as an alternative, is expensive and time-consuming. As meat and fish differ in their stable isotope ratios, δ(13)C and δ(15)N have been proposed as biomarkers. However, they have never been investigated in controlled human dietary intervention studies.

OBJECTIVE

In a short-term feeding study, we investigated the suitability of δ(13)C and δ(15)N in blood, urine and faeces as biomarkers of meat and fish intake.

METHODS

The dietary intervention study (n = 14) followed a randomised cross-over design with three eight-day dietary periods (meat, fish and half-meat-half-fish). In addition, 4 participants completed a vegetarian control period. At the end of each period, 24-h urine, fasting venous blood and faeces were collected and their δ(13)C and δ(15)N analysed.

RESULTS

There was a significant difference between diets in isotope ratios in faeces and urine samples, but not in blood samples (Kruskal-Wallis test, p < 0.0001). In pairwise comparisons, δ(13)C and δ(15)N were significantly higher in urine and faecal samples following a fish diet when compared with all other diets, and significantly lower following a vegetarian diet. There was no significant difference in isotope ratio between meat and half-meat-half-fish diets for blood, urine or faecal samples.

CONCLUSIONS

The results of this study show that urinary and faecal δ(13)C and δ(15)N are suitable candidate biomarkers for short-term meat and fish intake.

The diet-body offset in human nitrogen isotopic values: a controlled dietary study

The "trophic level enrichment" between diet and body results in an overall increase in nitrogen isotopic values as the food chain is ascended. Quantifying the diet-body Δ(15) N spacing has proved difficult, particularly for humans. The value is usually assumed to be +3-5‰ in the archaeological literature. We report here the first (to our knowledge) data from humans on isotopically known diets, comparing dietary intake and a body tissue sample, that of red blood cells. Samples were taken from 11 subjects on controlled diets for a 30-day period, where the controlled diets were designed to match each individual's habitual diet, thus reducing problems with short-term changes in diet causing isotopic changes in the body pool. The Δ(15) N(diet-RBC) was measured as +3.5‰. Using measured offsets from other studies, we estimate the human Δ(15) N(diet-keratin) as +5.0-5.3‰, which is in good agreement with values derived from the two other studies using individual diet records. We also estimate a value for Δ(15) N(diet-collagen) of ≈6‰, again in combination with measured offsets from other studies. This value is larger than usually assumed in palaeodietary studies, which suggests that the proportion of animal protein in prehistoric human diet may have often been overestimated in isotopic studies of palaeodiet.

The earliest evidence of millet as a staple crop: New light on neolithic foodways in North China

There is a growing body of archaeobotanical evidence for the harvesting of millet in Eurasia prior to 5,000 cal. BC. Yet direct evidence for the extent of millet consumption in this time period is rare. This contradiction may be due to millet crops making only a minor contribution to the diet before 5,000 BC. In this article, drawing from recent excavations in North China, we present evidence for millet crops making a substantial contribution to human and animal diets in periods, which correspond chronologically with the time depth of the archaeobotanical record. We infer that in eastern Inner Mongolia, human adoption of millets, which may or may be not related to substantial agriculture, happened at the Early Neolithic, with direct dates between 5,800 and 5,300 cal. BC.

Changing cultures, changing cuisines: Cultural transitions and dietary change in Iron Age, Roman, and Early Medieval Croatia

Food is well-known to encode social and cultural values, for example different social groups use different consumption patterns to act as social boundaries. When societies and cultures change, whether through drift, through population replacement or other factors, diet may also alter despite unchanging resource availability within a region. This study investigates the extent to which dietary change coincides with cultural change, to understand the effects of large-scale migrations on the populations' diets. Through stable carbon and nitrogen isotope analysis of Iron Age, Roman, and Early Medieval human bone collagen, we show that in Croatia large-scale cultural change led to significant changes in diet. The isotopic evidence indicates that Iron Age diet consisted of C(3) foodstuffs with no isotopic evidence for the consumption of C(4) or marine resources. With the Roman conquest, marine resources were added to the diet, although C(3) foodstuffs continued to play an important role. In the Early Medieval period, this marine component was lost and varying amounts of C(4) foodstuffs, probably millet, were added to the otherwise C(3) diet. In both of these transitions it is likely that the changes in diet are related to the arrival of a new people into the area.

Stable isotope evidence for late medieval (14th-15th C) origins of the eastern Baltic cod (Gadus morhua) fishery

Although recent historical ecology studies have extended quantitative knowledge of eastern Baltic cod (Gadus morhua) exploitation back as far as the 16th century, the historical origin of the modern fishery remains obscure. Widespread archaeological evidence for cod consumption around the eastern Baltic littoral emerges around the 13th century, three centuries before systematic documentation, but it is not clear whether this represents (1) development of a substantial eastern Baltic cod fishery, or (2) large-scale importation of preserved cod from elsewhere. To distinguish between these hypotheses we use stable carbon and nitrogen isotope analysis to determine likely catch regions of 74 cod vertebrae and cleithra from 19 Baltic archaeological sites dated from the 8th to the 16th centuries. δ(13)C and δ(15)N signatures for six possible catch regions were established using a larger sample of archaeological cod cranial bones (n = 249). The data strongly support the second hypothesis, revealing widespread importation of cod during the 13th to 14th centuries, most of it probably from Arctic Norway. By the 15th century, however, eastern Baltic cod dominate within our sample, indicating the development of a substantial late medieval fishery. Potential human impact on cod stocks in the eastern Baltic must thus be taken into account for at least the last 600 years.

Ancient hybridization and an Irish origin for the modern polar bear matriline

BACKGROUND

Polar bears (Ursus maritimus) are among those species most susceptible to the rapidly changing arctic climate, and their survival is of global concern. Despite this, little is known about polar bear species history. Future conservation strategies would significantly benefit from an understanding of basic evolutionary information, such as the timing and conditions of their initial divergence from brown bears (U. arctos) or their response to previous environmental change.

RESULTS

We used a spatially explicit phylogeographic model to estimate the dynamics of 242 brown bear and polar bear matrilines sampled throughout the last 120,000 years and across their present and past geographic ranges. Our results show that the present distribution of these matrilines was shaped by a combination of regional stability and rapid, long-distance dispersal from ice-age refugia. In addition, hybridization between polar bears and brown bears may have occurred multiple times throughout the Late Pleistocene.

CONCLUSIONS

The reconstructed matrilineal history of brown and polar bears has two striking features. First, it is punctuated by dramatic and discrete climate-driven dispersal events. Second, opportunistic mating between these two species as their ranges overlapped has left a strong genetic imprint. In particular, a likely genetic exchange with extinct Irish brown bears forms the origin of the modern polar bear matriline. This suggests that interspecific hybridization not only may be more common than previously considered but may be a mechanism by which species deal with marginal habitats during periods of environmental deterioration.

Water-related occupations and diet in two Roman coastal communities (Italy, first to third century AD): correlation between stable carbon and nitrogen isotope values and auricular exostosis prevalence

The reconstruction of dietary patterns in the two Roman imperial age coastal communities of Portus and Velia (I-III AD) by means of stable isotope analysis of bone remains has exposed a certain degree of heterogeneity between and within the two samples. Results do not correlate with any discernible mortuary practices at either site, which might have pointed to differential social status. The present study tests the hypothesis of a possible connection between dietary habits and occupational activities in the two communities. Among skeletal markers of occupation, external auricular exostosis (EAE) has proved to be very informative. Clinical and retrospective epidemiological surveys have revealed a strong positive correlation between EAE development and habitual exposure to cold water. In this study, we show that there is a high rate of occurrence of EAE among adult males in both skeletal samples (21.1% in Portus and 35.3% in Velia). Further, there is a statistically significant higher prevalence of EAE among those individuals at Velia with very high nitrogen isotopic values. This points to fishing (coastal, low-water fishing) as the sea-related occupation most responsible for the onset of the ear pathology. For Portus, where the consumption of foods from sea and river seems to be more widespread through the population, and where the scenario of seaport and fluvial activities was much more complex than in Velia, a close correlation between EAE and fish consumption by fishermen is less easy to establish.

Radiocarbon and stable isotope investigations at the Central Rhineland sites of Gönnersdorf and Andernach-Martinsberg, Germany

The late glacial open-air sites of Gönnersdorf and Andernach-Martinsberg in the German Central Rhineland are well known for their Magdalenian occupation and activities. The latter site also produced evidence for a younger, Final Palaeolithic occupation of the locality by people of the Federmessergruppen. Both sites are particularly well preserved, largely due to their burial beneath volcanic deposits of the late glacial Laacher See eruption. We conducted a program of AMS radiocarbon dating and stable isotope analyses with the aim of improving understanding of the chronological history and ecological setting of the two sites. Previously published radiocarbon dates appeared to indicate that the earliest Magdalenian occupation at Gönnersdorf fell around 12,900 uncalibrated (14)C yr BP, while the earliest occupation at Andernach may have been more than 500 radiocarbon years earlier. The AMS determinations presented here revise this impression and suggest that the onset of occupation at the two sites was in fact simultaneous and prior to the warming of Greenland Interstadial GI 1e. At Gönnersdorf, a chronological hiatus exists between the main Magdalenian faunal assemblage and mega-faunal remains interpreted as collected sub-fossil material. At Andernach-Martinsberg, there is a clear chronological hiatus between the Magdalenian occupation and subsequent Federmessergruppen activities at the site. However, an intermediate radiocarbon date on an atypically preserved horse bone is suggestive of ephemeral human visits to the site between these well demonstrated phases. A date of similar age on an elk bone from Gönnersdorf may indicate broadly contemporaneous human presence at Gönnersdorf too. Stable isotope analysis of faunal remains from Gönnersdorf and Andernach-Martinsberg was conducted with the aim of both reconstructing and comparing local environmental conditions at the two sites, and also potentially identifying subtle variations in the chronological development of the two sites not detectable at the level of precision of current radiocarbon dating techniques. No spatial trends in the faunal isotope signatures were observed within each site. In the case of samples with both radiocarbon and isotope data, no chronological pattern was observed for the isotope results. The Magdalenian faunal isotope signatures at the two sites resembled each other, suggesting comparable climatic and environmental conditions. The faunal delta(13)C signatures at Gönnersdorf and Andernach-Martinsberg were similar to those at contemporary European sites. While the faunal delta(15)N values were similar to those at contemporary sites in Germany, the UK, and Belgium, they were lower than those from the South of France. This difference in delta(15)N values is thought to relate to regional differences in the timing of changes in soil and plant nitrogen cycling in response to ameliorating climatic conditions.

Sex-specific foraging strategies and resource partitioning in the southern elephant seal (Mirounga leonina)

The evolution of resource specializations is poorly understood, especially in marine systems. The southern elephant seal (Mirounga leonina) is the largest of the phocid seals, sexually dimorphic, and thought to prey predominantly on fish and squid. We collected vibrissae from male and female southern elephant seals, and assessed stable C and N isotope ratios along the length of the vibrissae. Given that whiskers grow slowly, this sampling strategy reflects any variation in feeding behaviour over a period of time. We found that isotopic variation among females was relatively small, and that the apparent prey choice and trophic level of females was different from that for males. Further, males showed a very broad range of trophic/prey choice positions, grouped into several clusters, and this included isotopic values too low to match a broad range of potential fish and cephalopod prey tested. One of these clusters overlapped with data for South American sea lions (Otaria flavescens), which were measured for comparison. Both male southern elephant seals and southern sea lions forage over the continental shelf, providing the potential for competition. We discuss the possibility that individual southern elephant seals are pursuing specialist foraging strategies to avoid competition, both with one another, and with the South American sea lions that breed nearby.

Nitrogen balance and delta15N: why you're not what you eat during nutritional stress

While past experiments on animals, birds, fish, and insects have shown changes in stable isotope ratios due to nutritional stress, there has been little research on this topic in humans. To address this issue, a small pilot study was conducted. Hair samples from eight pregnant women who experienced nutritional stress associated with the nausea and vomiting of morning sickness (hyperemesis gravidarum) were measured for carbon (delta13C) and nitrogen (delta15N) stable isotope ratios. The delta13C results showed no change during morning sickness or pregnancy when compared with pre-pregnancy values. In contrast, the delta15N values generally increased during periods of weight loss and/or restricted weight gain associated with morning sickness. With weight gain and recovery from nutritional stress, the hair delta15N values displayed a decreasing trend over the course of gestation towards birth. This study illustrates how delta15N values are not only affected by diet, but also by the nitrogen balance of an individual. Potential applications of this research include the development of diagnostic techniques for tracking eating disorders, disease states, and nitrogen balance in archaeological, medical, and forensic cases.

Nitrogen balance and delta15N: why you're not what you eat during pregnancy

Carbon (13C/12C) and nitrogen (15N/14N) stable isotope ratios were longitudinally measured in human hair that reflected the period from pre-conception to delivery in 10 pregnant women. There was no significant change in the delta13C results, but all subjects showed a decrease in delta15N values (-0.3 to -1.1 per thousand) during gestation. The mechanisms causing this decrease in hair delta15N have not been fully elucidated. However, since the delta15N values of dietary nitrogen and urea nitrogen are significantly lower compared to maternal tissues, it is hypothesized that the increased utilization of dietary and urea nitrogen for tissue synthesis during pregnancy resulted in a reduction of the steady state diet to a body trophic level effect by approximately 0.5-1 per thousand. An inverse correlation (R2 = 0.67) between hair delta15N and weight gain was also found, suggesting that positive nitrogen balance results in a reduction of delta15N values independent of diet. These results indicate that delta15N measurements have the ability to monitor not only dietary inputs, but also the nitrogen balance of an organism. A potential application of this technique is the detection of fertility patterns in modern and ancient species that have tissues that linearly record stable isotope ratios through time.

Differential relations between cognition and 15N isotopic content of hair in elderly people with dementia and controls

BACKGROUND

Previous researchers have suggested that a vegetarian diet or one rich in fish may protect against Alzheimer's disease (AD). However, assessing diet is difficult in AD patients. (15)N:(14)N isotopic ratios (delta(15)N) of body proteins can estimate long-term dietary habits in a way that does not depend on memory. delta(15)N is high in people who eat a lot of fish and low in vegetarians.

METHODS

To choose between the vegetarian and fish hypotheses of AD, we compared dietary questionnaire reports and delta(15)N of hair samples from AD patients and controls.

RESULTS

Patients' cognitive scores related directly to reported frequency of eating fish and to hair delta(15)N(AIR), but inversely to reported frequency of eating beans. Homocysteine levels related inversely to hair delta(15)N(AIR) in controls, but not in patients. Dietary questionnaire reports accounted for slightly more variance in delta(15)N(AIR) in patients than controls. Therefore, our questionnaire assessed dietary habits as reliably for individuals with AD as for cognitively unimpaired controls.

CONCLUSIONS

A diet rich in fish may ameliorate AD, possibly by lowering homocysteine, but more vegetarian diets do not. In fact, eating beans correlated with worse cognition in AD patients. Further studies should test if restricting the intake of beans slows the progression of AD.

The omnivorous Tyrolean Iceman: colon contents (meat, cereals, pollen, moss and whipworm) and stable isotope analyses

The contents of the colon of the Tyrolean Iceman who lived ca. 5300 years ago include muscle fibres, cereal remains, a diversity of pollen, and most notably that of the hop hornbeam (Ostrya carpinifolia) retaining cellular contents, as well as a moss leaf (Neckera complanata) and eggs of the parasitic whipworm (Trichuris trichiura). Based almost solely on stable isotope analyses and ignoring the work on the colon contents, two recently published papers on the Iceman's diet draw ill-founded conclusions about vegetarianism and even veganism. Neither the pollen nor the moss is likely to have been deliberately consumed as food by the Iceman. All the available evidence concerning the Iceman's broad-based diet is reviewed and the significance of the colon contents for matters other than assessment of food intake is outlined.

Investigations into the effect of diet on modern human hair isotopic values

Carbon and nitrogen isotopic analysis of body tissues is one of the few techniques that can furnish quantitative information about the diet of archaeological humans. The study of the effects of various diets on modern human isotopic values can help to refine palaeodietary theories, and such work also enables the testing of palaeodietary theories independent of archaeological remains and interpretations. This report discusses the use of modern human hair as a sample material for isotopic analysis. The biogenic carbon and nitrogen isotopic signal is well preserved in hair, and the isotopic values of the keratin can be related to diet. We show that atmospheric and cosmetic contamination of hair keratin does not appear to affect the measured isotopic values. In a small study of Oxford residents, we demonstrate that the magnitude of the nitrogen isotopic values of hair keratin reflects the proportion of animal protein consumed in the diet: omnivores and ovo-lacto-vegetarians have higher delta15N than vegans. There was an observed relationship between the reported amount of animal protein eaten (either meat or secondary animal products) and the nitrogen isotopic values within the two groups of omnivores and ovo-lacto-vegetarians, indicating that an increasing amount of animal protein in the diet results in an increase in the delta15N of hair keratin. This provides the first independent support for a long-held theory that, for individuals within a single population, a diet high in meat equates to elevated nitrogen isotopic values in the body relative to others eating less animal protein. The implications of such results for the magnitude of the trophic level effect are discussed. Results presented here also permit a consideration of the effects of a change of diet in the short and long term on hair keratin isotopic values.

Documenting the diet in ancient human populations through stable isotope analysis of hair

Fundamental to the understanding of human history is the ability to make interpretations based on artefacts and other remains which are used to gather information about an ancient population. Sequestered in the organic matrices of these remains can be information, for example, concerning incidence of disease, genetic defects and diet. Stable isotopic compositions, especially those made on isolates of collagen from bones, have been used to help suggest principal dietary components. A significant problem in the use of collagen is its long-term stability, and the possibility of isotopic alteration during early diagenesis, or through contaminating condensation reactions. In this study, we suggest that a commonly overlooked material, human hair, may represent an ideal material to be used in addressing human diets of ancient civilizations. Through the analysis of the amino-acid composition of modern hair, as well as samples that were subjected to radiation (thus simulating ageing of the hair) and hair from humans that is up to 5200 years old, we have observed little in the way of chemical change. The principal amino acids observed in all of these samples are essentially identical in relative abundances and content. Dominating the compositions are serine, glutamic acid, threonine, glycine and leucine, respectively accounting for approximately 15%, 17%, 10%, 8% and 8% of the total hydrolysable amino acids. Even minor components (for example, alanine, valine, isoleucine) show similar constancy between the samples of different ages. This constancy clearly indicates minimal alteration of the amino-acid composition of the hair. Further, it would indicate that hair is well preserved and is amenable to isotopic analysis as a tool for distinguishing sources of nutrition. Based on this observation, we have isotopically characterized modern individuals for whom the diet has been documented. Both stable nitrogen and carbon isotope compositions were assessed, and together provide an indication of trophic status, and principal type (C3 or C4) of vegetation consumed. True vegans have nitrogen isotope compositions of about 7/1000 whereas humans consuming larger amounts of meat, eggs, or milk are more enriched in the heavy nitrogen isotope. We have also analysed large cross-sections of modern humans from North America and Europe to provide an indication of the variability seen in a population (the supermarket diet). There is a wide diversity in both carbon and nitrogen isotope values based at least partially on the levels of seafood, corn-fed beef and grains in the diets. Following analysis of the ancient hair, we have observed similar trends in certain ancient populations. For example, the Coptics of Egypt (1000 BP) and Chinchorro of Chile (5000-800 BP) have diets of similar diversity to those observed in the modern group but were isotopically influenced by local nutritional sources. In other ancient hair (Egyptian Late Middle Kingdom mummies, ca. 4000 BP), we have observed a much more uniform isotopic signature, indicating a more constant diet. We have also recognized a primary vegetarian component in the diet of the Neolithic Ice Man of the Oetztaler Alps (5200 BP). In certain cases, it appears that sulphur isotopes may help to further constrain dietary interpretations, owing to the good preservation and sulphur content of hair. It appears that analysis of the often-overlooked hair in archaeological sites may represent a significant new approach for understanding ancient human communities.