Stable Carbon Isotope Analysis Research Articles

Microfacies and stable isotope analyses (δ13C and δ18O) of the upper Serpukhovian-Moscovian carbonates in the Hadim Nappe, southern Turkey: an approach to document the Late Paleozoic Ice Age (LPIA)

Microfacies and stable isotope analyses (δ13C and δ18O) of the upper Serpukhovian-Moscovian carbonates in the Hadim Nappe, southern Turkey: an approach to document the Late Paleozoic Ice Age (LPIA)

Interpreting past trophic ecology of a threatened alpine parrot, kea Nestor notabilis, from museum specimens.

When ecosystems are under severe pressure or environments change, trophic position and intraspecific niche width may decrease or narrow, signalling that conservation action is required. In New Zealand, alpine and subalpine ecosystems have been extensively modified through farming since 19th-century European settlement, with consequences for indigenous species such as the kea Nestor notabilis. We investigated feather stable isotope values in the kea and predicted a lower trophic position in modern kea populations, to reflect reduced lowland habitat and a mixed diet with more plant material. We predicted that size and sex would influence trophic values in this sexually dimorphic species, with larger birds more likely to have a high protein diet. We examined potential dietary changes in 68 museum collected kea from 1880s to 2000s, first recording accession details including provenance and sex and measuring culmen length. We used bulk carbon and nitrogen stable isotope analyses (BSIAs) of feathers and a further feather subset using compound-specific stable isotope analyses of amino acids (CSIA-AA) to obtain isotopic values and estimate trophic position. BSIA showed δ15 N values in kea feathers declined through time and could indicate that early century kea were highly omnivorous, with δ15 N values on average higher than in modern kea. Variance in δ15 N values was greater after 1950, driven by a few individuals. Few differences between males and females were evident, although females in the south region had lower δ15 N values. There was a tendency for large male birds to have higher trophic values, perhaps reflecting dominant male bird behaviour noted in historical records. Nonetheless, CSIA-AA performed on a subset of the data suggested that variation in BSIA is likely due to baseline changes rather than relative trophic position which may be more homogenous than these data indicate. Although there was more variability in modern kea, we suggest caution in interpretation. Stable isotope data, particularly CSIA-AA, from museum specimens can reveal potential change in ecological networks as well as sexually dimorphic feeding patterns within species. The data can reveal temporal and regional variation in species trophic position and changes in ecosystem integrity to inform conservation decision-making.

Phthalate esters (PAEs) concentration pattern reflects dietary habitats (δ13C) in blood of Mediterranean loggerhead turtles (Caretta caretta)

Phthalic acid esters (PAEs) are classified as endocrine disruptors, but it remains unclear if they can enter the marine food-web and result in severe health effects for organisms. Loggerhead turtles (Caretta caretta) can be chronically exposed to PAEs by ingesting plastic debris, but no information is available about PAEs levels in blood, and how these concentrations are related to diet during different life stages. This paper investigated, for the first time, six PAEs in blood of 18 wild-caught Mediterranean loggerhead turtles throughout solid-phase extraction coupled with gas chromatography-ion trap/mass spectrometry. Stable isotope analyses of carbon and nitrogen were also performed to assess the resource use pattern of loggerhead turtles. DEHP (12–63 ng mL-1) and DBP (6–57 ng mL-1) were the most frequently represented PAEs, followed by DiBP, DMP, DEP and DOP. The total PAEs concentration was highest in three turtles (124–260 ng mL-1) whereas three other turtles had concentrations below the detection limit. PAEs were clustered in three groups according to concentration in all samples: DEHP in the first group, DBP, DEP, and DiBP in the second group, and DOP and DMP in the third group. The total phthalates concentration did not differ between large-sized (96.3 ± 86.0 ng mL-1) and small-sized (67.1 ± 34.2 ng mL-1) turtles (p < 0.001). However, DMP and DEP were found only in large-sized turtles and DiBP and DBP had higher concentrations in large-sized turtles. On the other hand, DEHP and DOP were found in both small- and large-sized turtles with similar concentrations, i.e. ~ 21.0/32.0 ng mL-1 and ~ 7.1/9.9 ng mL-1, respectively. Winsored robust models indicated that δ13C is a good predictor for DBP and DiBP concentrations (significant Akaike Information criterion weight, AICwt). Our results indicate that blood is a good matrix to evaluate acute exposure to PAEs in marine turtles. Moreover, this approach is here suggested as a useful tool to explain the internal dose of PAEs in term of dietary habits (δ13C), suggesting that all marine species at high trophic levels may be particularly exposed to PAEs, despite their different dietary habitats and levels of exposure.

Pig Management Strategies in the East Liao River Basin From the Bronze Age (c. 2000–256 BC) to the Liaojin Dynasties (907–1234 AD): Stable Isotope Analysis of Animals at the Changshan Site, Jilin Province, China

Pig domestication and management strategy has been increasingly discussed in recent years, focusing on the temporal-spatial differences of pig management strategies. The East Liao River Basin with diverse ecosystems, cultural exchanges, and collisions plays an important role in the cultural development, exchange, and integration processes between Northeast China and the Central Plains. Multiple studies have revealed that various forms of subsistence economy, such as nomadism, fishing and hunting, and farming, existed in this region. However, no report or discussion has been presented concerning the status of domestic animal management strategies over a long-term in the East Liao River Basin. Carbon and nitrogen stable isotopes analysis were performed on the fauna bones at the Changshan site in Siping, Jilin, China, from the Bronze Age (c. 2000–256 BC) to the Liaojin Dynasties (907–1234 AD), to reconstruct their dietary pattern and reveal the status of domestic animal management strategies, especially the diachronic changes in pig feeding strategies. The results showed that pigs (–19.3 ± 1.6%, 5.3 ± 0.9%, n = 27), horses (–18.4 ± 1.7%, 4.8 ± 1.4%, n = 7), and sheep (–19.8 ± 1.5%, 5.7 ± 0.5%, n = 6) primarily received their subsistence through C3-based food. Nevertheless, cattle (–16.4 ± 3.5%, 6.0 ± 2.1%, n = 2) and the past human (–13.9%, 10.3%, n = 1) lived on mixed C3/C4-based food. Notably, the stable isotope data for pigs from the Bronze Age (–19.1 ± 2.0%, 5.4 ± 1.0%, n = 9) to the Liaojin Dynasties (–19.8 ± 0.6%, 5.1 ± 0.7%, n = 15) were similar, indicating that the management and/or feeding strategy of domestic pigs were relatively stable with a free range in a wild ecosystem over a long period. Related studies have shown that pigs in captivity were mainly fed by millet-based food in the West Liao River Basin and the middle reaches of the Yellow River valley, where millet agriculture were adequately developed. Abundant natural resources, including plants, wild animals, and fishes, could provide sufficient food to the past population in the East Liao River Basin. Thus, the millet-based agriculture was just an auxiliary subsistence strategy in the Changshan site, leading to a gap in the driving force for long-term intensive management of pig.

The differences in the trophic structure of semi‐enclosed and open coastal communities under the influence of an alien top predator (red king crab in the Barents Sea)

AbstractThe impact of the introduced red king crab (RKC), Paralithodes camtschaticus, in the Barents Sea was mostly studied through its direct predation on native species. This study uses stable isotope analysis of carbon and nitrogen to characterize major trophic groups (including grazing sea urchins) and specifically looks at RKC's trophic position and niche partitioning with the native hermit and spider crab species. To achieve this, we sampled organisms from the food web of a small fjord‐like Zelenaya Inlet on the Murmansk coast in the southwestern Barents Sea and the open sea coast, just outside the inlet for comparison. There, macrophyte‐derived carbon is the major source of organic matter along with the phytoplankton. In general, the fucoid source of primary production was more prominent within the inlet food web compared to the nearby open coastal zone. Isotopic trophic niches calculated using SIBER analysis showed partition between the native hermit and spider crabs suggesting, some degree of trophic segregation between coevolved species. RKCs are clustered together in the center of native decapod species' niches. There were some distinct differences between the feeding habits of RKCs within the inlet and the open sea coastal waters. The subadult RKCs that are present in the inlet throughout the year have a narrower (in the area and specifically in δ15N dimension) niche than the adults from the open sea. The latter have a wider variety of food items due to their migration and may prey on food items from different trophic levels. Sea urchins are an important trophic link transferring the macrophyte carbon to RKC. However, P. camtschaticus may also directly consume plant residues. Despite generally similar calculated trophic levels of decapod species, our isotopic data and literature data on the food composition of Paralithodes camtschaticus in the Barents Sea do not indicate significant RKC's competition with, and predation on, native species of crabs.

Detailed Carbon Isotope Study of PM2.5 Aerosols at Urban Background, Suburban Background and Regional Background Sites in Hungary

The aim of this study was to estimate and refine the potential sources of carbon in the atmospheric PM2.5 fraction aerosol at three sampling sites in Hungary. Quantification of total, organic and elemental carbon (TC, OC and EC, respectively), as well as radiocarbon (14C) and stable carbon isotope analyses were performed on exposed filters collected at an urban background site, a suburban background site of the capital of Hungary, Budapest from October 2017 to July 2018. Results were also collected from the rural regional background site of K-puszta. Compared to TC concentrations from other regions of Europe, the ratio of the lowest and highest values at all sites in Hungary are lower than these European locations, probably due to the specific meteorological conditions prevailing in the Carpathian Basin over the observation period. The concentration of OC was constantly higher than that of EC and a seasonal variation with higher values in the heating period (October–March) and lower values in the non-heating vegetation period (April–September) could be observed for both EC and OC fractions. Using 14C, the seasonal mean fraction of contemporary carbon (fC) within the TC varied between 0.50 and 0.78 at the sites, suggesting that modern sources were remarkable during the year, regardless of the heating or vegetation period. At the two urban sites, assuming constant industrial emission during the year, the fossil fuel combustion sources were responsible for the seasonal variation of EC, while modern carbon emissions from biomass-burning and biogenic sources influenced the OC concentration. The higher EC/TC ratios at these sites were associated with lower fC and δ13C values, which can be explained by soot emission from transportation. The notably high EC/TC ratios in the spring were likely caused by the reduced concentration of OC instead of increased EC concentrations. This could probably be caused by the ending of winter biomass burning, which emits a huge amount of OC into the atmosphere. On the contrary, the rural K-puszta site showed some differences relative to the sites in Budapest. No correlation could be revealed between the EC/TC ratio, fC and δ13C results, suggesting that the structure of sources was very stagnant and balanced in each season. In autumn, however, some less depleted values were observed, and agricultural corn-stalk burning after harvesting in the southern and eastern directions from Hungary can be suggested as the main source.

Stable Carbon Isotope Analysis of Hexachlorocyclohexanes by Liquid-Liquid Extraction Gas Chromatography Isotope Ratio Mass Spectrometry: Method Evaluation and Applications.

Compound specific isotope analysis (CSIA) and enantiomer specific isotope analysis (ESIA) are powerful tools for assessing the fate of hexachlorocyclohexanes (HCHs) in the environment. However, there is no systematic study on the CSIA and ESIA analysis test methods of the carbon isotopes of HCHs in water and soil environments, in particular the isotope fractionation in the pre-concentration process. We endeavored to test the compatibility of CSIA and ESIA with the liquid–liquid extraction method of HCHs in water. The results showed that there were negligible changes in the δ13C of HCHs after extraction, indicating that liquid–liquid extraction can be used as a pre-concentration method for the determination of δ13C of HCHs in water. The optimized method was validated and then applied to differentiate three HCHs from different manufacturers, to identify in situ degradation of HCHs of groundwater from a contaminated site and to resolve the carbon isotope fractionation occurring in the α-HCH oxidation by CaO2/Fe(II) Fenton system. The results showed that the same reagents from different manufacturers have different carbon isotope compositions, and different isomers from the same manufacturer also have different isotope compositions, showing useful evidence in identifying the source of HCHs. The more enriched δ13C in the down-gradient wells indicated that HCHs have undergone biodegradation or/and chemical reactions in the groundwater system of the site. Carbon isotopic enrichment factors (εC) of −1.90 ± 0.10‰ were obtained in the oxidation process. Hence, the method validated in this study has great potential as a method for identifying the degradation of HCHs in a water environment.

Can forest trees take up and transport nanoplastics?

Plastic contamination of ecosystems has increased dramatically over the last decades, raising concerns about the negative impacts of plastic particles on aquatic and terrestrial systems. In recent years, the focus of most research has shifted from large fragments (macroplastic) to micro- (<5 mm) and more recently to nano-plastic (<1000 nm) particles as more evidence has come to light about their ubiquity in water, soils, and living systems, and their effects on ecosystem and human health. In this study, we investigate nanoplastic uptake in the roots of seedlings (1-2 years old) of three different tree species and assess their transport to different tissues. Parts of the main roots of silver birch (Betula pendula Roth), sessile oak (Quercus petraea Matt. [Liebl.]), and Norway spruce (Picea abies [L.] Karst.) were immersed for one or four days in a suspension containing 13C-labelled nano-sized polystyrene particles (13C-nPS; 99% 13C, d = 28 ± 8 (1 σ) nm). Carbon stable isotope analysis showed significant 13C enrichment (P < 0.05) in the immersed part of the root after one day of treatment in all three species, and after four days in Q. petraea alone. Signals of significant 13C enrichment were also found in the aboveground tissues of the trees. The stem of B. pendula in particular showed a significant 13C enrichment after one day of treatment (P < 0.01). This indicates that nanoplastic particles can be taken up through tree roots into the tree’s central cylinder, where they are subsequently conveyed through the tree by acropetal transport via the xylem.

Genesis of wavy carbonate flowstone deposits in Bossea Cave (North Italy) and their hydroclimatic significance

Speleothems show an array of shapes. Flowstones are commonly tabular sheet-like deposits, which cover cave floors and walls. They can procure detailed information about past hydrogeological conditions through their morphology, geochemical composition and stratigraphic properties, which in turn are related to the climate conditions at the surface. This is possible if the climate and environmental factors controlling the formation of these deposits are well understood. In Bossea Cave (north-east Italy), we have investigated highly symmetrical wavy flowstones that have never been described in detail before. These deposits show a cyclical repetition of sloped and sub-vertical layers, with knickpoints migrating downslope. This paper investigates the origin of these peculiar carbonate deposits, using: i) terrestrial laser scanning surveys; ii) petrographic observations; iii) oxygen and carbon stable isotope analyses; iv) hydrochemical monitoring data of feeding waters. According to these analyses, we have generated a genetic model that demonstrates: 1) laminar flow of CaCO3–rich water prevails during the deposition of the flowstone; in accordance, the final flowstone architecture does not appear to be influenced by random irregularities of the underlying bedrock substrate. 2) The peculiar morphology is inherited by ripples occurring in the flowing water films during carbonate deposition, which trigger the precipitation of regularly spaced CaCO3 deposits along the bedrock slopes. Because of these ripple-induced initial deposits, calcite then deposits as sloped and sub-vertical layers, giving rise to a wavy-like morphology. 3) Wavy calcite layers are only deposited after heavy rainfall events occurred within two to four consecutive rainy days (10 to 20 mm/hour during rainfall peaks; average rates between 3.5 and 7.0 mm/hour); in contrast, calcite deposition cannot occur during low rainfall events (less than 5 mm/hour during rainfall peaks, average rates around 0.8 mm/hour). We therefore propose that the studied wavy flowstones are hydroclimatic indicators, testifying the occurrence of flashy type recharge related to heavy rainfall events. Similar deposits could record these same hydro-climatic conditions in other karst areas.In recent decades, storms have caused more frequent flooding in highly populated Mediterranean areas, especially in Italy. Wavy flowstones may offer a new archive to gain a better understanding of the long-term dynamics of intense precipitation events and, thus, help to improve future climate scenarios.

Crop manuring on the Beauce plateau (France) during the second iron age

The studied area on the Beauce plateau (France) was densely inhabited during the Iron Age and several archaeological excavations have enriched our knowledge of agrarian systems during this period. This study investigates fertilisation management between 400 and 80 BCE focusing on numerous crop storage remains from three neighbouring farms. We sampled 18 cereal groups with 50 grains to conduct stable carbon and nitrogen isotope analyses commonly used for reconstructing past agricultural practices, in particular δ15N as a proxy for manuring.The δ15N values range between 1.3‰ and 7.6‰, with an increase over time from 3.2‰ to 5.6‰ (mean by occupation phase), reflecting a continuous use of manure, consistent with the dynamism of agricultural activities during the Second Iron Age. All three farms seem to have applied the same manuring strategies. Barley and emmer may have been manured more often than free-threshing wheats, even when free-threshing wheats are the dominant crop. This contrasts with the neighbouring Ile-de-France region and indicates diversity in agropastoral systems between regions. The analysis of several grain groups from the same silo shows diversified δ15N values between crops, reflecting various manuring rates: some fields were fertilised while others were less so. This is consistent with the description of a large-scale farming system, with a large cultivated area and a mosaic landscape.

Isotopic reconstruction of short to absent breastfeeding in a 19th century rural Dutch community.

Artificial feeding of young infants is considered a modern phenomenon. However, historical sources note its practice in some past European populations. This research explores factors that contributed to a short to absent period of breastfeeding in pre-modern Netherlands. Stable nitrogen and carbon isotope analysis is undertaken on 277 19th century individuals from Beemster, a, rural, mainly Protestant, dairy farming community. An intra-individual sampling approach for ≤6 year-olds compares newer metaphyseal to older diaphyseal long bone collagen to classify feeding status at death. Archivally identified individuals permit analyses of sex and year-of-death. Few infants have isotopic evidence for breastfeeding and, if present, it was likely of short duration or a minor source of dietary protein. From only a few weeks to months of age infants were fed cow’s milk and paps with sugar. There is broad dietary homogeneity with no sex or temporal isotopic differences, but young infants (1–11 months) have the most ẟ15N and ẟ13C variation highlighting the effect of multiple dietary and physiological processes. Beemster had many factors associated with high rates of breastfeeding in other Dutch communities, yet, most mothers did not breastfeed, or not for long, showing that regional variation in infant feeding is influenced by community values and traditions. On top of child rearing and domestic chores, female dairy farmers were in charge of milking cattle and dairy production, an important income source, suggesting high workload was also a factor in short or absent breastfeeding periods, aided by the constant supply of fresh milk that could be fed to an infant by an older sibling.

Petrology, mineralogy and geochemistry of Ordovician rocks in the southwest of Tarim Basin, implications for genetic mechanism and evolution model of the hydrothermal reformed-paleokarst carbonate reservoir

Paleokarst carbonate reservoir plays an important role in the exploration of oil and gas from shallow to ultra-deep strata. Multistage karstification is superimposed to form the present ultra-deep karst-hydrothermal reformed carbonate reservoirs in the Yubei area of the Tarim Basin. Based on petrology identification, stable carbon and oxygen isotope analysis, inductively coupled plasma mass spectrometry (ICP-MS), and Laser Ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), we investigated paleokarst periods, chemical property of hydrothermal fluids, and the evolution model and formation mechanism of paleokarst-hydrothermal reformed Ordovician carbonate reservoirs. The results show that the Ordovician strata experienced five periods of karstification from the middle Caledonian period to the late Himalayan period. The Caledonian quasi-contemporaneous karst and the Hercynian epigenetic karstification provided the most fundamental pore – fracture framework for carbonate reservoirs, and the later multistage deep burial karstification re-transformed the established reservoir space by hydrothermal dissolution under thermochemical sulfate reduction (TSR) reaction. It is proposed that the thermal convection between the hydrothermal fluids from the upper mantle and carbonate rocks formed two kinds of hydrothermal fluids in Ordovician strata. The first kind of hydrothermal fluid is performed with a SiO2-enriched fluid under the acidic environment based on TSR, forming siliceous cements and hydrothermal dissolution pores in the Lower Ordovician strata. The second kind of hydrothermal fluids appeared as an alkaline CO32—enriched fluid with the reversible reaction between HCO3− and CaCO3, forming hydrothermal calcite and dolomite near the migration channel in Upper Ordovician carbonate rocks. The periodic changes of in situ trace element concentrations of multistage quartz fillings indicated that paleokarst reservoirs are controlled by thermal convection under episodic tectonic activity. As a summary, we established the migration pattern of hydrothermal fluids in the thin section scale and the evolution model of the hydrothermal reformed paleokarst reservoirs in basin scale.

Variation in diet of frugivorous bats in fragments of Brazil’s Atlantic Forest associated with vegetation density

AbstractSpecies distribution and persistence have long been known to vary with landscape structure; however, continued human activities in altered landscapes raise many questions as to how habitat fragmentation impacts the biology of persistent animal populations. Using carbon and nitrogen stable isotope analysis, we examined interspecific variation in the diet of frugivorous bats among remnant habitat patches of Brazil’s Atlantic Forest. We hypothesized that the diet of individuals captured in habitat patches would be different than those captured in contiguous habitats. We predicted that bats would alter their realized dietary niche breadth, taking food items (i.e., fruits or insects) according to landscape structure. However, more mobile species should be less impacted by small-scale landscape changes. We predicted that (1) a wide-ranging species (Artibeus lituratus), which move through open areas, will be less affected by small-scale landscape attributes, patch size, composition, and isolation; while (2) two narrow-ranging species (Carollia perspicillata and Sturnira lilium) will have more variation between populations in niche breadth and isotopic ratio ranges dependant on the local environment. Using Akaike’s Information Criterion (AIC) to rank a priori selected candidate models to explain variation, we found that fragment composition, largely involving vegetation density rather than spatial aspects of landscape structure (i.e., patch area, isolation) best explained diet variation in frugivorous bats. Additionally, there was evidence that wide-ranging A. lituratus were less impacted by differences in the landscape than narrow-ranging species. This supports the prediction that bats resident to fragments have altered feeding behavior, in response to environmental perturbation.

Carbon and oxygen stable isotopic evidence for diverse sheep and goat husbandry strategies amid a Final Bronze Age farming milieu in the Kyrgyz Tian Shan

AbstractThe mountains of Central Asia during the Bronze and Iron Ages are increasingly being reconceived as an important zone for intensive crop cultivation in combination with pastoralist herding. However, very little information is known about how farming practices intersected with livestock husbandry, especially at high‐elevation sites. This paper presents the first insights to ancient animal management strategies in the Tian Shan through incremental carbon and oxygen stable isotope analysis of domesticated caprine teeth recovered from the Chap‐1 farmstead located at 2000 m.a.s.l. in Kyrgyzstan (1065 to 825 cal BCE). We implemented a fully reproducible analysis of time‐series isotope data in the R programming language. Results show subtle but variable manipulation of domesticated caprine diets at subannual scales, suggesting mixed strategies of providing access to a small amount of C4 plant biomass, in addition to summer movements to high pastures where the overall carbon isotopic composition of graze was depleted in 13C compared with that of the environs of the site or lowland pastures. Nevertheless, caprine dietary intake was overwhelmingly dominated by C3 plants. Analysis of domesticated caprine birth seasonality reveals off‐season fall and winter births, which represent a common strategy employed by ancient producers in Central Asia to improve herd security and extend meat and milk availability. This study illustrates a well‐integrated system of agro‐pastoralist production that can help clarify the social dynamics underlying food systems in the mountain regions of Central and Inner Asia in the Final Bronze Age. It further reveals the capability for more sedentary agro‐pastoralist communities to facilitate wider interregional cultural connections, through limited seasonal herding mobility and investment in highland settlement.

Stable isotope differences of polar bears in the Southern Beaufort Sea and Chukchi Sea

AbstractThe life‐history, genetic, and habitat use differences between the 2 polar bear (Ursus maritimus) subpopulations in Alaska, USA, have been used to determine the geographic border separating them, but it has sparked a debate of the correct placement of the border for several years. Recently, the Southern Beaufort Sea (SBS) polar bear subpopulation has declined because of sea ice loss, while the Chukchi Sea (CS) subpopulation appears stable. To provide additional information about potential differences between the SBS and CS subpopulations, such as differences in prey sources, we used stable isotope analysis of carbon and nitrogen from bone collagen of polar bears in these 2 neighboring subpopulations. We analyzed polar bear bones from 112 individuals collected from 1954–2019. Our purpose was to determine if the SBS and CS subpopulations could be distinguished based on the stable isotope signatures of bone collagen. A difference &gt;1‰ in stable carbon isotope (δ13C) values suggests a change in carbon sources, such as nearshore to offshore, while a 3‰ change in stable nitrogen isotope (δ15N) values equates to a change of about 1 trophic level. Our study indicated a difference in δ13C values (P ≤ 0.001) but not δ15N values (P = 0.654) between the CS (−13.0 ± 0.3‰ and 22.0 ± 0.9‰, respectively) and SBS bears (−14.7 ± 1.3‰ and 22.2 ± 1.0‰, respectively). Our findings indicate that the 2 subpopulations are consuming similar high trophic level prey, while feeding in ecosystems with different δ13C baselines. We performed a logistic regression analysis using δ13C and δ15N values of the polar bears to predict their placement into these 2 subpopulations. Using Icy Cape, Alaska as the geographical boundary, the analysis correctly placed polar bears in their respective subpopulations 82% of the time. Overall accuracy of placement changed to 84% when using the current geographical boundary at Utqiaġvik, Alaska. We predicted samples collected from the Wainwright, Alaska region as 58% CS and 42% SBS polar bears. This suggests that the area between Wainwright and Icy Cape is a polar bear mixing zone that includes bears from both subpopulations. Bone collagen has a long‐term, potentially life‐long, stable isotope turnover rate, and our results could be used to determine the association of harvested polar bears to Alaska subpopulations, thus aiding in transboundary harvest quota management.

The cave bears from Imanay Cave (Southern Urals, Russia)

ABSTRACT In the rich vertebrate fauna of Imanay Cave the abundant material of the small-sized cave bears was originally assigned to the taxon Ursus savini. Teeth and metapodials of statistical amounts were compared with other cave bear faunas and the taxonomic position was determined through morphological and metric analyses. The size of teeth and metapodial bones is significantly smaller in Imanay Cave bears compared to the typical U. deningeri from Mosbach and Hundsheim. Although the teeth are smaller, they reached higher evolutionary level than those from Mosbach or Hundsheim.The bear remains from Imanay Cave show great similarities to the fossils from Kizel Cave in the Ural Mountains described as Ursus rossicus Borissiak, 1930 but also to the remains of small-bodied cave bears of the Alps described as Ursus deningeroides Mottl, 1964. Remarkable are the differences in size of the front dentition: the incisors from Imanay Cave are on average >10% longer and wider than the corresponding teeth from U. deningeroides but also wider than the classic U. deningeri. Preliminary carbon and nitrogen stable isotope analyses suggest that the small cave bears from Imanay Cave were herbivorous.

The Bodies in the \u2018Bog\u2019: A Multi-Isotope Investigation of Individual Life-Histories at an Unusual 6th/7th AD Century Group Burial from a Roman Latrine at Cramond, Scotland

This study utilises multi-isotope approaches to investigate early medieval diet and childhood origins of individuals interred in an unusual group burial from Lothian, Scotland. In 1976, the skeletal remains of nine adults and five infants were unearthed from the infill of a latrine of a bathhouse at the Roman fort at Cramond, Edinburgh. Originally thought to be later medieval (14th/15th century), but recently dated to the 6th century AD, these remains represent a rare opportunity to gain deeper insights into the dietary histories and lifetime mobility of the inhabitants of early medieval south-central Scotland. Bone and teeth from the adults (n=9) were sampled, along with local faunal bone from a range of species (n=12). Long-term dietary trends were explored using stable carbon (δ13C), nitrogen (δ15N) and sulphur (δ34S) isotope analyses of bone collagen, focusing on inter-individual variability and the potential inclusion of marine protein in the diet. Sulphur (δ34S) was also utilised as a possible indicator of later-life mobility. Strontium (87Sr/86Sr) and oxygen (δ18OCARB) ratios of tooth enamel were employed to identify potential locals and non-locals, as well as possible locations of childhood origin. No intra-group dietary variability was detected, and the results are similar to other contemporary populations from southern Britain. The sulphur isotope data indicate that all of the individuals likely lived locally in their last few decades of life. However, based on isotopic data from tooth enamel, at least one or perhaps two of the individuals likely spent their childhoods in other locations.

The burial Ogonyok in the middle Lena River region: a new site of the Bel'kachi Culture

The article presents the results of a comprehensive study of the Ogonyok burial, discovered and investigated in 2016 in the city of Yakutsk, Central Yakutia, in the middle reaches of the Lena River. The purpose of the study was to determine its cultural and chronological characteristics, to identify the features of the funeral rite and spe-cifics of the accompanying grave goods. In addition to historical and archaeological methods, the methods of tra-sological analysis of stone tools, radiocarbon dating and date calibration, isotope analysis of human and animal bone collagen, and determination of the species composition of the fauna that was part of the burial equipment were used. The burial place was destroyed during land works, as such, only part of the accompanying equipment and osteological material was preserved for the analyses. Excavations of the remains of the burial were carried out, which made it possible to determine approximately its orientation, the position of the deceased and the depth from the day surface. Similarities to the accompanying goods, which included a flint core and three blades, an arrowhead, polished adze, bone composite arrowhead with a blade in the groove, anthropomorphic figurine from a mammoth tusk, fragments of a bone polisher and a needle, as well as faunal remains, were found in the com-plexes of the Bel'kachi Neolithic Culture of Northeast Asia of the end of the 5th–3rd mil. BC. Further analogies were identified in the synchronous Neolithic cultures of the Baikal, Transbaikalia, Lower Amur region, Primorsky Krai and Chukotka. The funeral ritual of filling the grave with ocher also brings the Ogonyok burial closer to other Bel'kachi cemeteries. Paleozoological analysis has shown that bones of lynx, wild reindeer and geese were pre-sent in the burial. Four AMS radiocarbon dates were obtained from human and animal bones, which attribute the burial in the first quarter of the 4th mil. BC. An interesting fact was the identification of an offset in the age of hu-man bones relatively to the age of animal bones, the former being approximately 200 years older, which is appa-rently associated with freshwater reservoir effect. Analysis of stable carbon and nitrogen isotopes demonstrated that the human diet was based on meat food, as well as, apparently, fish products, with a minor inclusion of wild plants. The burial of Ogonyok is one of the few “pure” sites of the Bel'kachi Neolithic Culture in Yakutia.

Absolute Carbon Stable Isotope Ratio in the Vienna Peedee Belemnite Isotope Reference Determined by 1H NMR Spectroscopy.

The Vienna Peedee Belemnite (VPDB) isotope reference defines the zero point of the carbon stable isotope scale that is used to describe the relative abundance of 13C and 12C. An accurate and precise characterization of this isotope reference is valuable for interlaboratory comparisons and conducting robust carbon stable isotope analyses in a vast array of fields, such as chemical forensics, (bio)geochemistry, ecology, or (astro)biology. Here, we report an absolute 13C/12C ratio for VPDB that has been obtained, for the first time, using proton nuclear magnetic resonance spectroscopy (1H NMR). Four different NMR instruments were used to determine 13C/12C ratios in a set of glycine reference materials from the US Geological Survey (USGS64, USGS65, and USGS66) and a set of formate samples that were characterized by isotope ratios mass spectrometry (IRMS). Intercalibration of the NMR-derived 13C/12C ratios with relative abundance (δ13CVPDB) measurements from IRMS yields a value of 0.011100 for the absolute 13C/12C ratio in VPDB, with an expanded uncertainty of ±0.000026 (2σ, n = 114). This is significantly different from the value of 0.011180 that is commonly used but falls within the range of values recently revised using IRMS and infrared absorption measurements. 1H NMR was found to be an effective method for measuring absolute 13C/12C ratios due to its ability to simultaneously detect signals associated with 12C and 13C. Results provide a new and independent measure of the carbon isotope composition of VPDB, improving our understanding of this important isotope reference.

Two Pathways Compete in the Mn(II)-Catalyzed Oxidation of Aminotrismethylene Phosphonate (ATMP).

Mn(II)-catalyzed oxidation by molecular oxygen is considered a relevant process for the environmental fate of aminopolyphosphonate chelating agents such as aminotrismethylene phosphonate (ATMP). However, the potential roles of Mn(III)ATMP-species in the underlying transformation mechanisms are not fully understood. We combined kinetic studies, compound-specific stable carbon isotope analysis, and equilibrium speciation modeling to shed light on the significance of such Mn-ATMP species for the overall ATMP oxidation by molecular oxygen. The fraction of ATMP complexed with Mn(II) inversely correlated with both (i) the Mn(II)-normalized transformation rate constants of ATMP and (ii) the observed carbon isotope enrichment factors (εc-values). These findings provide evidence for two parallel ATMP transformation pathways exhibiting distinctly different reaction kinetics and carbon isotope fractionation: (i) oxidation of ATMP present in Mn(III)ATMP complexes (εc ≈ -10 ‰) and (ii) oxidation of free ATMP by such Mn(III)ATMP species (εc ≈ -1 ‰) in a catalytic cycle. The higher reaction rate of the latter pathway implies that aminopolyphosphonates can be trapped in catalytic Mn-complexes before being transformed and suggests that Mn(III)ATMP might be a potent oxidant also for other reducible solutes in aqueous environments.