Human–environment interactions in medieval Poland: a perspective from the analysis of faunal stable isotope ratios

Stable isotope analyses of faunal remains provide valuable information about human–environment interactions in the past, including insights into past animal husbandry and land management strategies. Here, we report stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope values of collagen and carbonate from archaeological fauna from Ka?dus, a medieval settlement in North-Central Poland, to better understand human–environment interactions during a period of increasing urbanism and marketization. Wild and domestic animals can be separated on the basis of their isotopic values. The mean δ¹⁵N value for 12 domesticated animals is 7.6 ± 1.2‰ and for 5 wild animals is 4.3 ± 0.5‰ (p = 0.002). The mean collagen δ¹³C value for domesticated animals is −20.6 ± 1.1‰ and for wild animals is −22.0 ± 0.5‰ (p = 0.004). The mean carbonate δ¹³C value for domesticated animals is −13.14 ± 1.3‰ and for wild animals is −14.14 ± 0.9‰ (p = 0.034). The “canopy effect” and anthropogenic effects that alter stable isotope ratios of plants (manuring, swidden agriculture and ploughing) are discussed in relation to these differences. Fish are isotopically variable, which suggests broad-spectrum fishing strategies and/or trade, and increases our awareness of the difficulties in interpreting human paleodiet when freshwater fish were on the menu.     

Method-dependent variations in stable isotope results for structural carbonate in bone bioapatite

Stable carbon and oxygen isotope values (δ¹³C, δ¹⁸O) were obtained for structural carbonate in the bioapatite of archaeological bones from Guatemala and Sudan using several common analytical methods. For the Sudan samples, the different methods produced δ¹³C values within ±0.1‰ and δ¹⁸O values within ±0.7‰, on average. The isotopic results for the Guatemala samples were similar in reproducibility to the Sudan samples when obtained using methods that employed lower reaction temperatures and reactions in sealed vessels. However, many Guatemala samples had highly variable and extremely low δ¹⁸O values when reacted at higher temperatures in vessels that remained open to cryogenic traps. The latter arrangement caused reaction products to be removed immediately upon their production. The anomalously low δ¹⁸O values are related to the production of a contaminant gas that causes the m/z 46/44 ratio to be lowered, either by adding to the m/z 44 peak or subtracting from the m/z 46 peak. That said, potential contaminant materials were not detectable in “anomalous” bones using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, or inductively-coupled plasma atomic emission spectroscopy. However, subtle structural and chemical differences between “normal” and “anomalous” samples were observed, most notably in the FTIR ν₂ CO₃ domain. We suggest that these changes promote volatilization of an oxyphosphorus compound and oxygen isotope fractionation between PO⁻ derived from this compound and CO₂ derived from bone carbonate. Production of the contaminant gas and the related “anomalous” δ¹⁸O values is reversible if the reaction occurs within a sealed vessel for a sufficient period of time, which allows a “back-reaction” to occur.     

Provisioning Inka feasts at Tiwanaku, Bolivia: the geographic origins of camelids in the Pumapunku complex

While political integration can be achieved by many means, here we focus on the use of feasting and statecraft in the Inka Empire of the Andean Late Horizon (c. AD 1400-1532) in South America. In order to examine Inka political integration of the Lake Titicaca Basin of Bolivia, we examine paleomobility and paleodiet through radiogenic strontium and stable oxygen and carbon isotope data in archaeological camelid remains from the site of Tiwanaku. Mean radiogenic strontium isotope values from all archaeological camelid enamel and bone samples is ⁸⁷Sr/⁸⁶Sr = 0.70998 ± 0.00179 (1σ, n = 48), mean stable oxygen isotope values from a sub-set of archaeological camelid enamel and bone samples is δ¹⁸O_{carbonate (VPDB)} = −10.0‰ ± 2.6‰ (1σ, n = 18) and mean stable carbon isotope values from a sub-set of archaeological camelid enamel and bone samples is δ¹³C_{carbonate (VPDB)} = −9.0‰ ± 1.7‰ (1σ, n = 18). While many camelids consumed in these feasting events were likely local to the Lake Titicaca Basin, others came from a variety of different geologic zones, elucidating our understanding of Inka statecraft and the role of feasting in political integration in empires in the past.     

Migration and Viking Dublin: paleomobility and paleodiet through isotopic analyses

During the early medieval period in Ireland, Dublin was established as the largest Viking settlement on the island in the ninth century AD. A previous biodistance study has suggested that the population of the town consisted of a polyethnic amalgam of immigrant and indigenous. In this study, we use biogeochemistry to investigate paleomobility and paleodiet in archeological human remains from the ninth to eleventh century levels at the sites at Fishamble Street II (National Museum of Ireland excavation number E172), Fishamble Street III (E190) and John’s Lane (E173), as well as twelfth-century remains from Wood Quay (E132). Through radiogenic strontium isotope, stable oxygen, carbon, and nitrogen isotope, and elemental concentration analyses, we investigate the origins of the individuals who lived and died in early and late Viking Dublin. Mean archaeological human enamel and bone isotope values from Dublin are ⁸⁷Sr/⁸⁶Sr = 0.70975 ± 0.00139 (2σ, n = 22), δ¹³C_{carbonate(V-PDB)} = −14.8‰ ± 0.8‰ (1σ, n = 12), and δ¹⁸O_{carbonate(V-PDB)} = −7.2‰ ± 1.0‰ (1σ, n = 12). Archaeological human bone samples exhibit mean δ¹³C_{collagen(V-PDB)} = −20.8‰ ± 0.5‰ (1σ, n = 12) and mean δ¹⁵N_{collagen(AIR)} = +10.0‰ ± 1.7‰ (1σ, n = 12). Comparing these data with archaeological faunal data from Dublin and published data from northern Europe, we argue that there are no clear immigrants from other parts of the North Atlantic, although there is one clear outlier in both origins and diet. Overall, the relative homogeneity in both paleomobility and paleodiet may support models of acculturation in Viking Dublin, rather than a high number of first-generation immigrants or continued migration from Scandinavia.     

Evidence of physico–chemical and isotopic modifications in archaeological bones during controlled acid etching

It has been repeatedly shown that palaeoecological inferences from the elemental and isotopic content of carbonate hydroxylapatite of fossil teeth and bones are unrecoverable without removing diagenetic overprinting by chemical pretreatments. Such pretreatments may in turn cause modification of the biogenic signature. In this paper, we focus upon optimal removal of Ca–bearing carbonates (mainly calcite). In order to control the progress with time of calcite dissolution, we perform leaching under vacuum, and we monitor the evolution of the pH, pCO₂, δ¹³C of released CO₂, %C, δ¹³C and δ¹⁸O of the remaining mineral. For a set of different Quaternary bones and teeth, mass and isotopic balances indicate that 1 hour at most is necessary for complete dissolution of calcite with an optimal conservation of carbonate hydroxylapatite. Long–lasting experiments lead to a fractionation of hydroxylapatite ¹⁸O/¹⁶O carbonates.     

Alkaline cooking and stable isotope tissue-diet spacing in swine: archaeological implications

In this study we examine the effects of alkaline cooking on carbon and oxygen stable isotopic ratios of mineralized tissues from nine pigs raised on monotonous mixed C3/C4 vegetarian diets. Two sources of collagen (humerus and mandible) and two sources of apatite (humerus and enamel) were analyzed. Within each diet group, humerus and mandible collagens were found to record equivalent δ¹³C and δ¹⁸O ratios; however, enamel apatite was found to be enriched over bone apatite by 2.3‰ in carbon and 1.7‰ in oxygen. Alkaline cooking was found to slightly, but significantly increase the Δ¹³C_{collagen-diet} and Δ¹⁸O_{collagen-diet} of bone collagen. A similar trend towards enrichment was observed in bone and enamel Δ¹³C_apatite-diet and Δ¹⁸O _apatite-diet, but the differences were not significant. Observed isotopic shifts were consistent with increased nutrient utilization of the alkaline-cooked maize as compared to raw maize. In addition, a reexamination of the relationship between diet and tissue carbon isotopic values suggests that species and alimentary type should be considered when interpreting ancient diets.     

Horticulturists and oxygen ecozones in the tropical and subtropical forests of Southeast South America

We analyse the isotopic values (δ¹³C, δ¹⁵N) of the diet of pre-Columbian horticulturalist populations from tropical and subtropical areas of southeastern South America, belonging to the Guarani and Taquara archaeological units. The data indicate different trends in each one (T?=?4.21; P?=?0.0004), showing a mixed diet with maize consumption in the Guarani samples (δ¹³C_co?=??15.5?±?1.8‰; δ¹³C_ap ?10.4?±?0.8‰) and a depleted one in the Taquara ones (δ¹³C_co ?18.2?±?1.7‰; δ¹³C_ap ?11.9?±?0.9‰), with a significant internal dispersion in both populations. The first population has higher nitrogen values (δ¹⁵N 11.1?±?0.6‰) compared to the Taquara samples (δ¹⁵N 9.3?±?1‰), suggesting a more carnivorous diet. The recognition of these pre-Columbian mixed diets involves the identification of maize cultivation on the Atlantic side of the southernmost area of South America (Parana Delta, 34° SL). Through the analysis of δ¹⁸O we have identified two isotopic ecozones, the first along the Paraná River Valley, with an average value of δ¹⁸O ?3.7?±?0.5‰ (CV?=?13.5%; CI?=??3.83 / ?3.16), and the second one, located in the Planalto of southern Brazil (Araucaria Forest), with a mean value of δ¹⁸O ?1.5?±?0.3‰ (CV?=?16.5%; CI?=??1.69 / ?1.29). The isotopic data (δ¹³C, δ¹⁵N and δ¹⁸O) suggest human movements between these two ecozones.     

The effects of PVAc treatment and organic solvent removal on δ13C, δ15N,and δ18O values of collagen and hydroxyapatite in a modern bone

The stable isotopic analysis of archaeological and paleontological bones has become a common method to examine questions of ecology, climate, and physiology. As researchers addressing such questions incorporate museum collections in their studies, it is necessary to understand the isotopic effects of common preservation techniques utilized in such collections to ensure the preservation of original isotopic values. This study examines the effects of PVAc glue (polyvinyl acetate) applied in acetone solution and the subsequent removal of PVAc using various organic solvents on the δ¹³C and δ¹⁵N values of extracted bone collagen, the δ¹³C and δ¹⁸O values of carbonate in bone hydroxyapatite, and the δ¹⁸O values of phosphate in hydroxyapatite. The data demonstrate that isotopic values in the collagen and phosphate are unaffected by any combination of PVAc treatment and solvent application. The carbonates show little variation in δ¹³C values, but exhibit variable δ¹⁸O values upon exposure to the PVAc solution. It is here suggested that δ¹⁸O values from carbonates in PVAc-treated bones do not retain an original isotopic value and should not be included in future studies.     

Diagenesis in bone and enamel apatite carbonate; the potential of density separation to assess the original composition

This paper presents a new approach to the isotopic measurement of diagenetically altered archaeological bone apatite carbonate. We describe how the existing differential dissolution method may be combined with a new approach to remove diagenetically reformed material on the basis of its greater specific gravity. We show that heavier, more diagenetically altered fraction has a higher (altered) δ¹³C and also increased crystallinity within one individual. In addition, we proposed one potential tool to check the validity of bone carbonate by comparing bone collagen, enamel carbonate and bone carbonate values of δ¹³C and radiocarbon content from the same individual. In the case of Danebury cattle, we estimated the biogenic δ¹³C_apa value for DC83 and DC89, although it is still difficult to overcome diagenesis in order to meet the expected value, which is shown to be 1.9‰ (DC83) and 3.5‰ (DC89).     

Dietary adaptation during the Longshan period in China: stable isotope analyses at Liangchengzhen (southeastern Shandong)

Rice and millet were staple crops at Liangchengzhen, a late Neolithic Longshan site in Shandong, China, but the degree of dietary variation is not known. This study uses stable isotope analysis of human and faunal skeletal remains to quantitatively address the importance of these crops as well as terrestrial domesticates and aquatic resources in the diet at Liangchengzhen. Although no collagen could be extracted from the poorly preserved human bones, the δ¹³C stable isotope results for 2 apatite sample and 16 tooth enamel samples averaged −9.8‰ suggesting that diet was based on foods averaging from −24‰ to −18‰, with millet and millet-fed animals comprising at most approximately 25–30% of the diet. Pig faunal δ¹³C isotope values suggested that during the earlier Longshan period pigs were fed mainly millet with more C₃ foods such as rice included by the later Longshan period. Solid ceramic residues from two guan jar sherds produced δ¹³C values averaging −18‰ and δ¹⁵N values averaging +16‰, suggesting both vessels contained fish. The results of the study indicate that by the Longshan period, people in southeastern Shandong no longer relied as heavily on millet and that the agricultural crop of rice had increased in importance at Liangchengzhen. Unfortunately, without human collagen samples to provide nitrogen isotope results, we cannot estimate the relative contribution of aquatic and terrestrial protein to the diet of people at Liangchengzhen. In general, however, the pattern of a diverse agricultural system on the basis of the macrobotanical remains from Liangchengzhen is supported by the isotopic results.     

Diet and death in times of war: isotopic and osteological analysis of mummified human remains from southern Mongolia

This study presents the results of an isotopic analysis of nine naturally mummified individuals—three adults, two adolescents, one juvenile, and three infants—recovered from the Hets Mountain Cave site in southern Mongolia, where they had been secondarily deposited. All of the individuals show evidence of violent perimortem trauma, but no skeletal indicators of nutritional or disease-related stress. Multi-isotopic data (δ¹³C, δ¹⁵N, δ¹⁸O, ⁸⁷Sr/⁸⁶Sr, and ²⁰ⁿPb/²⁰⁴Pb) were characterized in multiple tissues from each individual when possible, in order to reconstruct diet composition and residential origin at different points in life. Specifically, δ¹³C and δ¹⁵N in bone carbonate and collagen (N = 8) and hair keratin (N = 4) were coupled with enamel carbonate δ¹⁸O and δ¹³C (N = 3) and enamel ⁸⁷Sr/⁸⁶Sr, and ²⁰ⁿPb/²⁰⁴Pb (N = 3) to assess diet and residential mobility in relation to skeletal indicators of health and trauma. Results are consistent with a persistence of mixed C₃/C₄ pastoral subsistence and general stability of diet composition over the life course, in contrast to contemporary accounts of widespread famine and a dependence on grains imported from China throughout the region. However, results also suggest that at least some individuals may have migrated to this region of southern Mongolia from elsewhere during life, meaning that their dietary isotopic profiles may not represent local subsistence patterns near the Hets Mountain Cave site. Overall, these results speak to the utility of life course oriented multi-isotopic analysis in complementing more top-down historical analyses in understanding variation in subsistence, nutrition, and migration in regions undergoing significant political and economic turmoil.     

Paleodiet reconstruction of Bronze Age Siberians from the mortuary site of Khuzhir-Nuge XIV,Lake Baikal

Paleodiet reconstruction using stable isotopes of carbon and nitrogen was carried out on individuals from the Bronze Age cemetery, Khuzhir-Nuge XIV on the western shore of Lake Baikal, Russian Federation. The cemetery contained 79 graves with 89 individuals and was in use between approximately 2700 and 2000 cal. B.C. with the exception of one burial, dated to around 4000 B.C. Archaeological and ethnographic evidence indicates that hunting and fishing were the main subsistence activities while gathering was less important. δ¹³C from collagen and carbonate apatite was analysed, along with δ¹⁵N from collagen. Bone mineral preservation was evaluated using Fourier transform infrared spectroscopy. δ¹³C and δ¹⁵N of collagen are positively correlated and reflect varying reliance on terrestrial mammals, fish, and seals from Lake Baikal. Lake Baikal biota exhibit considerable variation in δ¹³C at the base of the food web thus; there is variation in human δ¹³C (−20.1‰ to −16.2‰) despite the fact that there are no C₄ plants in the region. δ¹⁵N results (range 10.3‰–16.5‰) indicate that fish, and possibly seals, made up some of the diet for everyone, but in varying amounts relative to terrestrial herbivores. δ¹³C from carbonate is not correlated with δ¹³C from collagen, a situation that has been found in remains from other coastal sites. A mixed diet from both terrestrial and freshwater ecosystems is the most likely explanation. Analysis of mortuary variables within the cemetery reveals three distinct clusters of graves with variations in burial treatment among the clusters. δ¹⁵N values are significantly different among these clusters, suggesting an association between diet and mortuary customs.     

Paleodietary analysis of the prehistoric population of the Canary Islands inferred from stable isotopes (carbon,nitrogen and hydrogen) in bone collagen

Nitrogen and carbon isotope compositions were measured in the bone collagen from a total of 86 prehispanic samples of the Canary Islands, and hydrogen in 70, all of them with enough amount of bone collagen, and adequate N and C content. These samples belong to prehistoric population of El Hierro (n = 27), Tenerife (n = 18), and Gran Canaria (n = 41). Isotope compositions were also obtained for prehistoric and modern food resources that were likely consumed by these people. Marked differences were observed among the three islands regarding the three isotopes analyzed: the δ¹⁵N values were highest among the population of Gran Canaria (10.8‰ ± 0.9‰), who also showed the highest δD values (7 ± 8‰). The population of El Hierro showed the highest δ¹³C values (−18.6‰ ± 0.7‰). These data suggest a high consumption of marine products by the population from El Hierro, and also an important consumption of terrestrial meat or marine, piscivore fish, by the population from Gran Canaria, together with domesticated C₃ plants (barley and/or wheat), fruits of Ficus carica and other wild species, and goat products. Additionally, marked differences were observed between men and women, which suggest that women consumed a more vegetal-based diet, a finding which is in agreement with the higher proportion of teeth with carious lesions among women.     

The stable and radio-isotope chemistry of southeastern Utah Basketmaker II burials: dietary analysis using the linear mixing model SISUS,age and sex patterning,geolocation and temporal patterning

The Bayesian linear mixing model SISUS is used to reconstruct reliance on maize and intake of animal protein from the stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope values of 149 directly dated Basketmaker II burials. Maize is the primary dietary staple. δ¹³C values are also enriched by intake of yucca and wild C₄ plant foods but these resources are of minor importance in sampled diets. Animal protein intake is low and cottontail rabbits make the greatest contribution to female diets. Adolescent diets are indistinguishable from the diets of adult females and both groups are less reliant on artiodactyls than males. The δ¹³C and δ¹⁸O values of bone hydroxyapatite distinguish nursing infants and oxygen isotope values identify outsider adults relative to those local to the region where their deaths occurred. Most Utah Basketmaker II burials are contemporary with Black Mesa Lolomai phase occupations, postdating the Marsh Pass, AZ, White Dog phase. All burials in both studies were recovered from sheltered rather than open sites and reliance on maize does not increase over the temporal span of the Utah study, covering the two sigma range 415 BC–AD 322.     

Stable isotope evidence of human diet at the Nukdo shell midden site,South Korea

Carbon and nitrogen stable isotope analysis was undertaken on bone collagen extracted from archaeological human (n = 48) and animal (n = 45) skeletons from the Nukdo site, Location I C, South Korea. This shell midden and grave site is dated from the late Mumun (550–300 BC) to early Iron Age (300 BC-1 AD) periods. The herbivorous mammals fell within the range of C₃ consumers, with average values of δ¹³C = −21.0 ± 0.5‰ and δ¹⁵N = 3.6 ± 0.5‰ for deer (n = 16) and δ¹³C = −20.6 ± 0.5‰ and δ¹⁵N = 4.5 ± 2.0‰ for wild boar (n = 17). Humans from this site averaged δ¹³C = −18.3 ± 0.4‰ and δ¹⁵N = 11.2 ± 0.7‰ for adults (n = 15) and δ¹³C = −18.7 ± 0.7‰ and δ¹⁵N = 12.5 ± 1.1‰ for juveniles (n = 33). These δ¹³C values indicate that there was no significant input of C₄ plants in the human diets and this may be associated with the spread of rice agriculture in the Mumun period. Human bone collagen δ¹³C and δ¹⁵N values indicate that there was some consumption of marine foods, although the main protein sources were from terrestrial foods. The isotope data demonstrate that the humans at Nukdo had mixed diets that included marine and terrestrial protein, including C₃ plants such as rice. Finally, the isotope results from the juveniles indicate that weaning occurred before the age of 1.5 years in this period.     

Paleodiet in northern Chile through the Holocene: extremely heavy δN values in dental calculus suggest a guano-derived signature?

Dental calculus extracted from the teeth of 28 prehistoric human skeletons from coastal and valley archaeological sites in northern Chile that date from the Archaic period (∼2300 BC) to the Late Intermediate period (AD 1476) was analyzed for stable isotope (δ¹⁵N, δ¹³C) compositions. δ¹⁵N compositions were extremely heavy (+17.8 to +33.1‰), but comparable to some studies using conventional human biomaterials (hair, nail, muscle) at other prehistoric sites in northern Chile. There was a negative correlation between δ¹⁵N and δ¹³C for coastal sites, but a positive correlation for valley sites. Results for the valley sites point to a diet that was influenced by marine resources throughout all time periods. The unusually heavy δ¹⁵N values for the coastal sites require a dietary component with a δ¹⁵N composition significantly heavier than that of marine resources. The hyper-aridity at the study area (mean annual rainfall of 0.5–0.6 mm/year) is a likely contributing factor to the production of heavy δ¹⁵N values, but is unlikely to account for the heaviest δ¹⁵N values (>+30‰). One possible explanation for the heaviest δ¹⁵N values is that dietary components were impacted by isotopically-heavy guano, which is abundant in the region. Guano may have been used as a fertilizer during crop cultivation at the onset of the Formative period, continuing through the Historic period after Spanish contact. The indirect impact of guano from abundant bird habitats in the region may have influenced wild foodstuffs harvested throughout the pre-agricultural period. Results provide support for the utility of dental calculus as a proxy for obtaining stable carbon and nitrogen isotope signatures for use in paleodietary studies.     

Ancient hydrocarbon seeps from the Mesozoic convergent margin of California: carbonate geochemistry, fluids and palaeoenvironments

More than a dozen hydrocarbon seep‐carbonate occurrences in late Jurassic to late Cretaceous forearc and accretionary prism strata, western California, accumulated in turbidite/fault‐hosted or serpentine diapir‐related settings. Three sites, Paskenta, Cold Fork of Cottonwood Creek and Wilbur Springs, were analyzed for their petrographic, geochemical and palaeoecological attributes, and each showed a three‐stage development that recorded the evolution of fluids through reducing–oxidizing–reducing conditions. The first stage constituted diffusive, reduced fluid seepage (CH₄, H₂S) through seafloor sediments, as indicated by Fe‐rich detrital micrite, corroded surfaces encrusted with framboidal pyrite, anhedral yellow calcite and negative cement stable isotopic signatures (δ¹³C as low as ?35.5‰ PDB; δ¹⁸O as low as ?10.8‰ PDB). Mega‐invertebrates, adapted to reduced conditions and/or bacterial chemosymbiosis, colonized the sites during this earliest period of fluid seepage. A second, early stage of centralized venting at the seafloor followed, which was coincident with hydrocarbon migration, as evidenced by nonluminescent fibrous cements with δ¹³C values as low as ?43.7‰ PDB, elevated δ¹⁸O (up to +2.3‰ PDB), petroleum inclusions, marine borings and lack of pyrite. Throughout these early phases of hydrocarbon seepage, microbial sediments were preserved as layered and clotted, nondetrital micrites. A final late‐stage of development marked a return to reducing conditions during burial diagenesis, as implied by pore‐associated Mn‐rich cement phases with bright cathodoluminescent patterns, and negative δ¹⁸O signatures (as low as ?14‰ PDB). These recurring patterns among sites highlight similarities in the hydrogeological evolution of the Mesozoic convergent margin of California, which influenced local geochemical conditions and organism responses. A comparison of stable carbon and oxygen isotopic data for 33 globally distributed seep‐carbonates, ranging in age from Devonian to Recent, delineated three groupings that reflect variable fluid input, different tectono‐sedimentary regimes and time–temperature‐dependent burial diagenesis.     

Influence of seabird guano and camelid dung fertilization on the nitrogen isotopic composition of field-grown maize (Zea mays)

Organic fertilizers have the capacity to alter the nitrogen isotopic composition of plants. Camelid dung and seabird guano are two potentially important fertilizers in the agricultural systems of western South America, particularly Peru and Chile. This paper presents isotopic data (δ¹³C and δ¹⁵N) from field grown plants (maize, Zea mays) fertilized with the following four treatments: CO (control, no fertilizer applied), AS (ammonium sulfate, a chemical fertilizer), DU (camelid dung), and SG (seabird guano). Plants were grown in experimental plots in the Virú Valley, northern Peru. Plants fertilized with the chemical fertilizer presented very similar isotopic compositions compared to the control. Conversely, the camelid dung fertilized plants were characterized by higher δ¹⁵N values compared to the control plants (by 1.8 to 4.2‰ depending on the plant part). The seabird guano fertilized plants were greatly enriched in ¹⁵N in comparison to the control plants (by 11.3 to 20.0‰). The results of this study have important implications for the reconstruction of human diet using isotopic data derived from bone collagen and related tissues, particularly in the prehispanic Andes, but also in Europe and North America during the 19th century, when Peruvian seabird guano was used extensively. Specifically, the interpretation of the relative contributions of plant and animal protein to the diet on the basis of bulk isotopic compositions of bone collagen (or similar tissues) may be confounded by camelid dung fertilization if the carbon isotopic compositions of the two sources are similar. Likewise, the interpretation of the relative contributions of maize and marine protein may be confounded by seabird guano fertilization.     

Stable isotope analysis of dog,fox, and human diets at a Late Holocene Chumash village (CA-SRI-2) on Santa Rosa Island,California

Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope analyses of dog (Canis familiaris), island fox (Urocyon littoralis), and human bone collagen from CA-SRI-2 (AD 130–1830) on Santa Rosa Island, California provide a proxy of diet and the relationships between humans and these animals. Carbon isotopic signatures indicate that Native Americans and their dogs at CA-SRI-2 subsisted almost exclusively on marine resources, while the island fox ate primarily terrestrial foods. Nitrogen isotopes and archaeofaunal remains indicate that humans and dogs also ate higher trophic level foods, including finfishes, marine mammals, and seabirds with smaller amounts of shellfish. The CA-SRI-2 island foxes appear to have eaten higher amounts of terrestrial foods, similar to the diets observed in modern fox populations. These data generally confirm the commensal relationship assumed to exist between domesticated dogs and people, but the carbon isotopic composition of dogs is enriched ∼2‰ compared to humans. We hypothesize that the difference in carbon isotopes between dogs and humans may have resulted from a higher consumption of C3 plants with lower δ¹³C values by humans, or less likely from the ingestion by dogs of significant amounts of bone collagen, which is enriched by ∼4‰ over associated muscle.     

Stable Carbon and Oxygen Isotope Spacing Between Bone and Tooth Collagen and Hydroxyapatite in Human Archaeological Remains

Spacing between stable isotope values in bones and teeth is a valuable tool for examining dietary influences and diagenesis. This study examines carbon and oxygen isotope values from collagen and hydroxyapatite (structural carbonate and phosphate) in archaeological human bones and teeth to derive species‐specific correlation equations and isotope spacing values. The δ¹³C_collagen and δ¹³C_{structural carbonate} in bone and dentin collagen show a strong correlation (R = 0.87, 0.90, respectively) with an average Δ¹³C_carb‐coll spacing of 5.4‰. The consistency of this isotope spacing with other large mammals and in humans with both low and high protein intake (as indicated by enriched δ¹⁵N values) suggests a similar allocation of protein‐derived carbon and whole diet‐derived carbon to collagen and structural carbonates, respectively, as other terrestrial mammals regardless of absolute meat intake. The δ¹⁸O_{structural carbonate} and δ¹⁸O_phosphate show the strongest correlation in enamel (R = 0.65), weaker correlations in dentin (R = 0.59) and bone (R = 0.35), with an average Δ¹⁸O_carb‐phos of 7.8‰. This isotope spacing is slightly lower than previously reported for large mammals and limited available data for humans. The results potentially indicate species‐specific fractionations and differing access to body water and blood‐dissolved inorganic carbonates in the presence of collagen formation. The use of correlation between δ¹⁸O_{structural carbonate} and δ¹⁸O_phosphate to determine diagenetic state is not recommended. The strength of this correlation observed in bones and teeth is variable and alternate indicators of diagenetic state (i.e. C:N ratios of collagen) provide more robust and independent evidence of isotope preservation despite presence/absence of a strong isotope correlation. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.