Isotope partitioning between cow milk and farm water: A tool for verification of milk provenance.

RATIONALE: The oxygen and hydrogen isotope compositions of the water component of the milk from nine Italian dairy farms were studied together with the farm water for one year. The aim was to verify the importance of farm water and seasonal temperature variation on milk isotope values and propose mathematical relations as new tools to identify the milk origin. METHODS: Milk was centrifuged to separate the solids and then distilled under vacuum to separate water. δ(18 O/16 O) and δ(2 H/1 H) analyses of the water molecules were carried out using a water equilibrator online with a mass spectrometer. For oxygen and hydrogen isotope determination, water was equilibrated with pure CO2 for 7.5 h and with pure H2 for 5 h, respectively. The isotope ratio value is indicated with δ (expressed on the VSMOW/SLAP scale) as defined by IUPAC. RESULTS: The average annual isotope value of milk at the different cattle sheds is mostly related to the farm water suggesting that the drinking water is the most important factor influencing the isotopic values of the milk water. The milk/water fractionation factor correlates with the milking time and, thus, the seasonal temperature is best described by a 4th order polynomial regression line. A two-level check model was used to verify the milking provenance. CONCLUSIONS: This study shows that it is essential to analyze both milk and farm water to indicate provenance. A two-step verification tool, based on the difference between the measured and calculated δ(18 O/16 O)M values, and the difference between the calculated and estimated milk-water fractionation factors, allowed the source determination of milk. Both conditions must be met if the milk is considered to be from the Parmigiano-Reggiano production region. Although this approach was developed for this region, it can easily be tested and adapted to other dairy production areas.

Stable oxygen isotopes in water of concentrated liquid foodstuffs: Are the commonly determined values accurate?

RATIONALE: Oxygen isotope analysis of water molecules of liquid foodstuffs is commonly performed under isotopic equilibrium between water in the solution and the vapour water, assuming that the liquid water activity is equal to unity and that liquid water is an ideal mixture of H2 O isotopologues. A priori this behaviour is not realistic for all foodstuffs, which frequently are very concentrated solutions. In this paper we mainly consider "balsamic vinegar" with the aim of defining an appropriate procedure of oxygen isotope ratio analysis of water molecules in these concentrated solutions. METHODS: Isotope ratio mass spectrometry (IRMS) measurements of the oxygen isotope ratios (δ18 O values) were carried out on CO2 equilibrated with water molecules at 22 ± 0.1°C. Three independently calibrated, very low salinity waters were used as standards. RESULTS: For grape must and wine vinegar (density < 1.15 g/cm3 ) the δ18 O values for water determined directly on these solutions are "true" values. On the contrary, for balsamic vinegar with density higher than 1.15-1.20 g/cm3 , the δ18 O values obtained directly on the solutions are systematically different from those obtained on water produced by distillation of the same samples at 70°C under vacuum. CONCLUSIONS: In the case of balsamic vinegar with density higher than 1.15-1.20 g/cm3 , to avoid severe systematic errors, the isotopic analyses must be carried out on water obtained by distillation under stirring.

Stable isotope study on ancient populations of central sudan: Insights on their diet and environment.

OBJECTIVES: A contribution to the knowledge of the economy and the environmental surroundings of the populations living along the Nile valley in three different periods. MATERIALS AND METHODS: This study reports stable isotope analyses on apatite bone samples of 139 humans, 48 mammals, and 43 fish from the Al Khiday archaeological sites in Sudan. The bones belong to four archaeological periods: pre-Mesolithic, Mesolithic, Neolithic, and Meroitic. Data were processed statistically. RESULTS: A significant difference exists between the pre-Mesolithic and Mesolithic mean δ(18) Ow value and the mean of the modern Nile. The mean δ(18) Ow values for the Neolithic humans and bovids are very similar (+1.5‰ ±4‰, and -2‰, respectively) and more positive than the mean values of Mesolithic mammals and Pre-Mesolithic humans. The water ingested by Meroitic humans (+7‰ ± 2.5‰) is enriched in (18) O in respect to the water ingested by the Neolithic population. There is a separation in the δ(13) Cdiet values between the pre-Mesolithic humans (-14‰ ± 1‰) and Mesolithic mammals (-12‰ ± 2‰) group and the Neolithic humans (-18‰ ± 1‰), Meroitic humans (-19‰ ±1‰), Neolithic mammals (-21‰), and the modern (mean δ(13) Cdiet = -19‰ ±2‰) mammal group. DISCUSSION: The climate became warmer and more arid from the pre-Mesolithic/Mesolithic to the Meroitic period. The environmental conditions influenced the strategies of subsistence and, in particular, the changes occurring from the pre-Mesolithic to the Neolithic can be considered contemporaneous to the transition from hunting-gathering-fishing to cultivation-herding. Am J Phys Anthropol 160:498-518, 2016. © 2016 Wiley Periodicals, Inc.

A synergistic solution for fighting fraudulent practices in squid using light stable isotope ratios and lanthanide tracers.

To identify a novel optimized strategy for preventing fraudulent substitutions of squid species and origins, forty European squids (Loligo vulgaris) and forty flying squids (Todarodes sagittatus) from the Mediterranean Sea and Atlantic Ocean were analyzed for δ13C, δ15N, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, and Lu using isotope ratio mass spectrometry and inductively coupled plasma-mass spectrometry. While δ13C and δ15N variations were mainly species-related, they alone could not reliably distinguish samples. To address this issue, decision rules were developed using Classification and Regression Tree analysis. Threshold values for δ13C (-19.91‰), δ15N (14.87‰), and Pr (0.49 µg kg-1) enabled successful discrimination among Mediterranean European squids, Atlantic European squids, Mediterranean flying squids, and Atlantic flying squids, achieving over 90% accuracy, 81% precision, 80% sensitivity, and 93% specificity. This method holds promise for enhancing traceability and safety in the seafood industry, ensuring product integrity and consumer trust.

How do turbidite systems behave from the hydrogeological point of view? New insights and open questions coming from an interdisciplinary work in southern Italy.

Turbidite successions can behave either as aquitards or aquifers depending on their lithological and hydraulic features. In particular, post-depositional processes can increase rock permeability due to fracture development in the competent layers. Thus, at a local scale, turbidite systems warrant further detailed investigations, aimed at reconstructing reliable hydrogeological models. The objective of this work was to investigate from the hydrogeological perspective a turbiditic aquifer located in southern Italy, where several perennial and seasonal springs were detected. Considering the complex hydrodynamics of these systems at the catchment scale, to reach an optimal characterization, a multidisciplinary approach was adopted. The conceptual framework employed microbial communities as groundwater tracers, together with the physicochemical features and isotopic signature of springs and streams from water samples. Meanwhile, geophysical investigations coupled with the geological survey provided the contextualization of the hydrogeological data into the detailed geological reconstruction of the study area. This modus operandi allowed us to typify several differences among the samples, allowing identification of sources and paths of surface water and groundwater, along with diffuse groundwater outflow along streams. As a final result, a hydrogeological conceptual model was reconstructed, underlining how at a very local scale the lithologic, hydraulic, and geomorphological heterogeneity of the studied relief can lead to an improved hydrogeological conceptual model compared to that of other turbidite systems. These results open new questions about the hydrogeological behavior of turbiditic aquifers, which could be pivotal in future research. In fact, these systems could support relevant ecosystems and anthropic activities, especially where climate change will force the research of new (and probably less hydrogeologically efficient) water sources.

Intraspecific phylogenetic analysis of Siberian woolly mammoths using complete mitochondrial genomes.

We report five new complete mitochondrial DNA (mtDNA) genomes of Siberian woolly mammoth (Mammuthus primigenius), sequenced with up to 73-fold coverage from DNA extracted from hair shaft material. Three of the sequences present the first complete mtDNA genomes of mammoth clade II. Analysis of these and 13 recently published mtDNA genomes demonstrates the existence of two apparently sympatric mtDNA clades that exhibit high interclade divergence. The analytical power afforded by the analysis of the complete mtDNA genomes reveals a surprisingly ancient coalescence age of the two clades, approximately 1-2 million years, depending on the calibration technique. Furthermore, statistical analysis of the temporal distribution of the (14)C ages of these and previously identified members of the two mammoth clades suggests that clade II went extinct before clade I. Modeling of protein structures failed to indicate any important functional difference between genomes belonging to the two clades, suggesting that the loss of clade II more likely is due to genetic drift than a selective sweep.

Strontium and oxygen isotopes as indicators of Longobards mobility in Italy: an investigation at Povegliano Veronese.

The arrival of the Longobards in Northern Italy in 568 CE marked a period of renewed political stability in the Peninsula after the collapse of the Western Roman Empire. The trajectory of the spread of Longobards in Italy across the Alps and into the South is known from many literary sources. However, their mobility and residence patterns at a population level remain to be fully understood. Here we present a multi-isotopic analysis (87Sr/86Sr and 18O/16O) of 39 humans and 14 animals buried at the Longobard necropolis of Povegliano Veronese (VR, Italy; 6th-8th century CE), to address mode and tempo of the spread of this population in the Peninsula. The geographical location of Povegliano Veronese plays a key role: the site lies along the Via Postumia, which was one of the main ancient Roman roads of Northern Italy, representing an important route in post-classical Italy. The integration of isotopic data with the archaeological evidence allowed us to determine the presence of individuals from at least three different regions of origin, building a diachronic map of the dynamics of mobility of this group in northern Italy.

Strontium and stable isotope evidence of human mobility strategies across the Last Glacial Maximum in southern Italy.

Understanding the reason(s) behind changes in human mobility strategies through space and time is a major challenge in palaeoanthropology. Most of the time this is due to the lack of suitable temporal sequences of human skeletal specimens during critical climatic or cultural shifts. Here, we present temporal variations in the Sr isotope composition of 14 human deciduous teeth and the N and C stable isotope ratios of four human remains from the Grotta Paglicci site (Apulia, southern Italy). The specimens were recovered from the Gravettian and Epigravettian layers, across the Last Glacial Maximum, and dated between 31210-33103 and 18334-19860 yr cal BP (2σ). The two groups of individuals exhibit different 87Sr/86Sr ratios and, while the Gravettians are similar to the local macro-fauna in terms of Sr isotopic signal, the Epigravettians are shifted towards higher radiogenic Sr ratios. These data, together with stable isotopes, can be explained by the adoption of different mobility strategies between the two groups, with the Gravettians exploiting logistical mobility strategies and the Epigravettians applying residential mobility.

Bedrock geology affects foliar nutrient status but has minor influence on leaf carbon isotope discrimination across altitudinal gradients.

Carbon isotope discrimination (Δ13C) in plant leaves generally decreases with increasing altitude in mountains. Lower foliar Δ13C at high elevation usually is associated with higher leaf mass per area (LMA) in thicker leaves. However, it is unclear if lower foliar Δ13C in high-altitude plants is caused by improved photosynthetic capacity as an effect of higher nutrient, especially nitrogen, content in thicker leaves. We investigated trends of foliar Δ13C in four species, each belonging to a different plant functional type (PFT), across two altitudinal gradients, each on a different bedrock type (carbonate and silicate bedrock, respectively) in a region of the southern Alps (Italy) where the foliar Δ13C was not affected by water limitation. Our objective was to assess whether the altitudinal patterns of foliar Δ13C in relation to leaf morphology and foliar nutrients were conditioned by indirect control of bedrock geology on soil nutrient availability. The foliar Δ13C of the four species was mainly affected by LMA and, secondarily, by stomatal density (SD) but the relative importance of these foliar traits varied among species. Area-based nutrient contents had overall minor importance in controlling C discrimination. Relationships among foliar Δ13C, foliar nutrient content and leaf growth rate strongly depended on soil nutrient availability varying differently across the two gradients. In the absence of water limitation, the foliar Δ13C was primarily controlled by irradiance which can shape anatomical leaf traits, especially LMA and/or SD, whose relative importance in determining C isotope discrimination differed among species and/or PFT. Decreasing foliar Δ13C across altitudinal gradients need not be determined by improved photosynthetic capacity deriving from higher nutrient content in thicker leaves.

Isotope analyses to explore diet and mobility in a medieval Muslim population at Tauste (NE Spain).

The Islamic necropolis discovered in Tauste (Zaragoza, Spain) is the only evidence that a large Muslim community lived in the area between the 8th and 10th centuries. A multi-isotope approach has been used to investigate the mobility and diet of this medieval Muslim population living in a shifting frontier region. Thirty-one individuals were analyzed to determine δ15N, δ13C, δ18O and 87Sr/86Sr composition. A combination of strontium and oxygen isotope analysis indicated that most individuals were of local origin although three females and two males were non-local. The non-local males would be from a warmer zone whereas two of the females would be from a more mountainous geographical region and the third from a geologically-different area. The extremely high δ15N baseline at Tauste was due to bedrock composition (gypsum and salt). High individual δ15N values were related to the manuring effect and consumption of fish. Adult males were the most privileged members of society in the medieval Muslim world and, as isotope data reflected, consumed more animal proteins than females and young males.

Nutritional constraints in ombrotrophic Sphagnum plants under increasing atmospheric nitrogen deposition in Europe.

• We studied the effects of increasing levels of atmospheric nitrogen (N) deposition on nutrient limitation of ombrotrophic Sphagnum plants. • Fifteen mires in 11 European countries were selected across a natural gradient of bulk atmospheric N deposition from 0.1 to 2 g/m2  year-1 . Nutritional constraints were assessed based on nutrient ratios of N, phosphorus (P), and potassium (K) in Sphagnum plants collected in hummocks (i.e. relatively drier microhabitats) and in lawns (i.e. relatively wetter microhabitats). • Nutrient ratios in Sphagnum plants increased steeply at low atmospheric N input, but above a threshold of N deposition of c. 1 g/m2  year-1 the N : P and N : K ratios tended to saturation. Increasing atmospheric N deposition was also accompanied by a reduced retention of Ca and Mg in Sphagnum plants and a decreased stem volumetric density in hummock Sphagnum plants. • We suggest a critical load of N deposition in Europe of 1 g/m2  year-1 above which Sphagnum plants change from being N-limited to be K + P colimited, at N : P > 30 and N : K > 3.

Monitoring temporal trends of air pollution in an urban area using mosses and lichens as biomonitors.

Monitoring air quality by using living organisms as biomonitors has received increasing attention in recent years. However, rather few studies were based on the concomitant use of passive biomonitoring (based on the different sensitivity of living organisms to air pollution) and active biomonitoring (based on their capacity to accumulate pollutants in the tissues). We carried out a repeated survey of an urban area in Northern Italy, with the objective of comparing temporal trends of different kinds of air pollutants with bioindication (passive biomonitoring) and bioaccumulation (active biomonitoring) techniques. During a five-year interval, temporal patterns of moss metal concentrations underwent significant changes probably due to intercurring variations in the importance of different pollution sources. Nitrogen (N) concentration in moss tissues also decreased and was paralleled by increasing diversity of epiphytic lichens. Increasing δ(15)N in moss tissues suggested a higher contribution of oxidized N species compared with reduced N species.

Climatic factors influencing the isotope composition of Italian olive oils and geographic characterisation.

The purpose of this study was to investigate the possibility of identifying oil source areas by means of simple measurements on the natural samples avoiding time-consuming sample treatments. The oxygen and carbon isotopic values of 150 samples of extra-virgin olive oil from eight different Italian regions and from three different years of production were measured according to well-established techniques. Statistical treatments of the results obtained show a very good correlation of the delta(18)O of oil with latitude, mean annual temperature, and mean relative humidity at the collection site. No correlation is found with elevation and mean annual precipitation. The shift of the oil delta(18)O per degree centigrade of the mean annual temperature is quantitatively close to that calculated for atmospheric precipitation in continental areas. Accordingly, in our measurements, the year of oil production can be identified on the basis of the delta(18)O value (mean 2004 temperatures were higher than 2005 temperatures). On the contrary, the oil delta(13)C values show no correlation with the above variables but only with latitude and, consequently, are less suitable for discriminating the geographic origin of oil. However, the delta(13)C values are suitable to indicate biological differentiation while the delta(18)O values are not.

Whole-genome shotgun sequencing of mitochondria from ancient hair shafts.

Although the application of sequencing-by-synthesis techniques to DNA extracted from bones has revolutionized the study of ancient DNA, it has been plagued by large fractions of contaminating environmental DNA. The genetic analyses of hair shafts could be a solution: We present 10 previously unexamined Siberian mammoth (Mammuthus primigenius) mitochondrial genomes, sequenced with up to 48-fold coverage. The observed levels of damage-derived sequencing errors were lower than those observed in previously published frozen bone samples, even though one of the specimens was >50,000 14C years old and another had been stored for 200 years at room temperature. The method therefore sets the stage for molecular-genetic analysis of museum collections.

Atmospheric nitrogen deposition promotes carbon loss from peat bogs.

Peat bogs have historically represented exceptional carbon (C) sinks because of their extremely low decomposition rates and consequent accumulation of plant remnants as peat. Among the factors favoring that peat accumulation, a major role is played by the chemical quality of plant litter itself, which is poor in nutrients and characterized by polyphenols with a strong inhibitory effect on microbial breakdown. Because bogs receive their nutrient supply solely from atmospheric deposition, the global increase of atmospheric nitrogen (N) inputs as a consequence of human activities could potentially alter the litter chemistry with important, but still unknown, effects on their C balance. Here we present data showing the decomposition rates of recently formed litter peat samples collected in nine European countries under a natural gradient of atmospheric N deposition from approximately 0.2 to 2 g.m(-2).yr(-1). We found that enhanced decomposition rates for material accumulated under higher atmospheric N supplies resulted in higher carbon dioxide (CO2) emissions and dissolved organic carbon release. The increased N availability favored microbial decomposition (i) by removing N constraints on microbial metabolism and (ii) through a chemical amelioration of litter peat quality with a positive feedback on microbial enzymatic activity. Although some uncertainty remains about whether decay-resistant Sphagnum will continue to dominate litter peat, our data indicate that, even without such changes, increased N deposition poses a serious risk to our valuable peatland C sinks.

Continuous-flow delta18O measurements: new approach to standardization, high-temperature thermodynamic and sulfate analysis.

The continuous-flow method for the determination of the O-isotope composition of solid samples has significant advantages over off-line extraction methods, but the problem has arisen of the standardization of results that has only partially been resolved by the use of water standards. We propose a new approach to standardization that uses carbothermic reduction of calcium carbonate standards catalyzed by high-purity AgCl. Analytical accuracy, precision, variance homogeneity and long-term stability are proven. Preliminary data on the barium sulfate delta18O analyses are reported, with a closer look at the different results obtained by off-line and on-line methods on intercomparison standards NBS-127 and MSS3.