Stable isotopes in the shell organic matrix for (paleo)environmental reconstructions.

Stable isotope ratios of mollusc shell carbonates have long been used to reconstruct past environmental conditions. Although shells also contain organics, they are seldom used in (paleo)climatic studies. Here, we extract the acid-soluble and insoluble fractions of the organic matrix of modern Mytilus galloprovincialis shells from three sites along a coast-to-upper-estuary environmental gradient to measure their hydrogen (δ2H) and oxygen (δ18O) isotope compositions. Both organic fractions showed isotopic signatures significantly different from those of carbonate and water at each site, indicating the involvement of different fractionation mechanisms. The soluble fraction showed gradual differences in isotope values along the gradient, while the insoluble fraction showed δ2H-δ18O correlation regressions subparallel to the Global and Local Meteoric Water Lines. These results showed the great potential of the shell organic matrix stable isotopes as possible (paleo)environmental proxies, stimulating further research to better define the fractionation mechanisms involved.

Near-infrared hyperspectral imaging to map collagen content in prehistoric bones for radiocarbon dating.

Many of the rarest prehistoric bones found by archaeologists are enormously precious and are considered to be part of our cultural and historical patrimony. Radiocarbon dating is a well-established technique that estimates the ages of bones by analysing the collagen still present. However, this method is destructive, and its use must be limited. In this study, we used imaging technology to quantify the presence of collagen in bone samples in a non-destructive way to select the most suitable samples (or sample regions) to be submitted to radiocarbon dating analysis. Near-infrared spectroscopy (NIR) that was connected to a camera with hyperspectral imaging (HSI) was used along with a chemometric model to create chemical images of the distribution of collagen in ancient bones. This model quantifies the collagen at every pixel and thus provides a chemical mapping of collagen content. Our results will offer significant advances for the study of human evolution as we will be able to minimise the destruction of valuable bone material, which is under the protection and enhancement of European cultural heritage and thus allow us to contextualise the valuable object by providing an accurate calendar age.

Variability and distribution of parasites, pathologies and their effect on wild mussels (Mytilus sp) in different environments along a wide latitudinal span in the Northern Atlantic and Arctic Oceans.

Histopathological examination in mussels can provide useful information for the diagnosis of ecosystem health status. The distribution of parasites in mussels can be conditioned by several environmental factors, including mussels collecting sites or the presence/absence of other species necessary to complete the complex life cycle of certain parasites. Thus, these variables could not only govern the parasitic burden of mussels but also the presence of pathologies associated to parasitism. The aim of this study was to identify the histopathological alterations which could be indicative of a health status distress along a wide latitudinal span in the Northern Atlantic and Arctic Oceans in mussels of two size-classes sampled in clean and impacted sites. A latitudinal gradient is clearly observed in gamete developmental stages as northern and southern mussels presented different conditions at the same period. Furthermore, mussels of the same size in different latitudes presented differences in the reproductive cycle and the appearance of related pathologies, which probably meant the age of individuals was different. In addition, specific parasitic profiles ruled by latitudinal conditions and the settlement of mussels in the shore (horizontal/vertical) have been demonstrated to be significantly influential in the health condition of mussels. Furthermore, the present work provides the first histological description of Gymnophallus cf. bursicola parasite causing a considerable host response in Tromsø and Iceland plus the report of grave histopathological status that included high prevalence of granulocytomas in Scotland and Germany.

A 41,500 year-old decorated ivory pendant from Stajnia Cave (Poland).

Evidence of mobiliary art and body augmentation are associated with the cultural innovations introduced by Homo sapiens at the beginning of the Upper Paleolithic. Here, we report the discovery of the oldest known human-modified punctate ornament, a decorated ivory pendant from the Paleolithic layers at Stajnia Cave in Poland. We describe the features of this unique piece, as well as the stratigraphic context and the details of its chronometric dating. The Stajnia Cave plate is a personal 'jewellery' object that was created 41,500 calendar years ago (directly radiocarbon dated). It is the oldest known of its kind in Eurasia and it establishes a new starting date for a tradition directly connected to the spread of modern Homo sapiens in Europe.

Exploring different methods of cellulose extraction for 14C dating.

In this study we aim to identify the optimal cellulose extraction protocol for 14C dating of wood, with a focus on glacial trees. To achieve this, we compare three cellulose extraction methods on the basis of cellulose yield and 14C age. The study is conducted on 12 wood samples of different species, in varying states of preservation with ages covering the full 14C age range. Cellulose is extracted from each sample following three different protocols selected from the literature: ABA-B, BABAB and 2Chlorox. The extracted cellulose was graphitised and dated with the MICADAS (Mini Carbon Dating System) at the ETH AMS laboratory. Although all three methods are considered efficient, the BABAB protocol, despite being a more aggressive procedure, allows the extraction of a sufficient amount of cellulose to be 14C dated and leads to the most reliable results, particularly for very old and background samples (samples with 14C content of zero).