Dental calculus is not equivalent to bone collagen for isotope analysis: a comparison between carbon and nitrogen stable isotope analysis of bulk dental calculus, bone and dentine collagen from same individuals from the Medieval site of El Raval (Alicante, Spain).

Palaeodietary reconstruction using the carbon and nitrogen isotope values of bone and dentine collagen is a well-established method and the biochemical processes involved are well known. Researchers have recently explored using bulk samples of dental calculus as a substitute for bone and dentine collagen in dietary analyses, because calculus can be sampled without causing damage to the teeth, and may be useful in situations where more destructive analyses are not possible, or where collagen is poorly preserved. Several questions remain about the use of bulk calculus as a source of carbon and nitrogen isotope data, however. It is not yet clear how much of an individual¿s life span dental calculus represents, what portions of the diet it records, and how diagenesis effects the carbon and nitrogen isotope values of this material. Most importantly, there have been no comparative studies of collagen and calculus isotope values, which are necessary to establish the value of bulk calculus as a source of accurate isotope values. Here we report the comparison of carbon and nitrogen stable isotope analyses of bulk calculus to those from bone and dentine collagen. These analyses have been performed on individuals from the El Raval Mudéjar Medieval Cemetery (Eastern Iberia, 15th century A.D.). Although calculus isotope values may be broadly similar to expected values at the population level, we report here no correlation between collagen and bulk dental calculus values at the individual level. As a result, we recommend that carbon and nitrogen analysis on bulk dental calculus should only be used as a last resource archaeological dietary marker, if at all

Nutrición infantil y salud ósea

Producción CientíficaMantener un adecuado estado nutricional en todas las etapas de la vida es decisivo para lograr un metabolismo óseo que favorezca la salud. La osteoporosis se caracteriza por una alteración en la cantidad y calidad de la mineralización ósea, lo que origina una fragilidad del esqueleto con riesgo aumentado de fracturas, especialmente vertebrales y de cadera. Es un problema público a nivel mundial, que afecta a una proporción elevada de hombres y mujeres, y que se desarrolla de forma asintomática hasta que se manifiesta de forma imprevista y causa una fractura del esqueleto. Estudios en niños han demostrado que el desarrollo de osteoporosis en la edad adulta puede verse condicionada por el estado nutricional durante la infancia, especialmente en lo referente a los aportes de calcio y vitamina D. No obstante, existen aún muchas cuestiones abiertas, tanto en lo referente a su patogenia y diagnóstico como a su tratamiento; algunas de éstas se revisan en este trabajo

Diving into the vertical dimension of elasmobranch movement ecology

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements

Diving into the vertical dimension of elasmobranch movement ecology

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements

Variations in bone collagen δ13C and δ15N values of fauna from Northwest Europe over the last 40 000 years

We report here a signal in the temporal variation of stable isotopes in protein from surviving animal bone in Northwest Europe over the past glacial cycle. There is a change in the average δ13C values of fauna in the Holocene, and there is also a significant reduction in δ15N values of herbivore bone collagen towards the end of the last glaciation, with a subsequent recovery soon after the start of the Holocene. This change is observed for several species and is restricted to those regions most affected by the glacial advance. Comparison with ice core data shows that there is a strong correlation between the average δ13C values of three herbivore species and ice core CO2 concentration. The data presented here show how readily available faunal bone collagen δ13C and δ15N measurements provide a record of past climate and environmental change on a regional to continental scal

Sharp shift in diet at onset of Neolithic

The introduction of domesticated plants and animals into Britain during the Neolithic cultural period between 5,200 and 4,500 years ago is viewed either as a rapid event1 or as a gradual process that lasted for more than a millennium2. Here we measure stable carbon isotopes present in bone to investigate the dietary habits of Britons over the Neolithic period and the preceding 3,800 years (the Mesolithic period). We find that there was a rapid and complete change from a marine- to a terrestrial-based diet among both coastal and inland dwellers at the onset of the Neolithic period, which coincided with the first appearance of domesticates. As well as arguing against a slow, gradual adoption of agriculture and animal husbandry by Mesolithic societies, our results indicate that the attraction of the new farming lifestyle must have been strong enough to persuade even coastal dwellers to abandon their successful fishing practices

Bone as a stable isotope archive for local climatic information

This brief review outlines the contribution that the study of stable isotope composition in bone can make to palaeoclimatic investigation, with the focus almost entirely restricted to the last 50,000 years in NW Europe. Bone can provide a useful archive of the prevailing isotopic condition, and represents a quite different, and often less specialised, sampling of the environment than most other archives. On the other hand, chronological sequences—and dating generally—can be a problem, and the link between the isotopic value registered in the bone, and the environmental conditions which gave rise to it, is both complex and not fully understood. Carbon, oxygen and nitrogen isotopes are all available from bone (nitrogen only where sufficient protein (collagen) survives), and are all subject, in different ways, to climatic influences such as temperature, rainfall, changes in floristic composition, and soil chemistry. These are all briefly discussed, and the datasets that are being published are considered in the context of the environmental information they provide. Undoubtedly environmental signals are recoverable, but their interpretation is still primitive. A dataset for carbon and nitrogen isotope composition of herbivores that spans the last 50,000 years is shown together with some of the issues it raises