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Reconstructing element concentrations in sediment cores helps identify historical natural or human-induced environmental changes. This study investigates variations in 15 element concentrations in Red Sea (a hot spot for biodiversity) sediment cores over the past five centuries. The findings reveal a significant change in sediment element accumulation rates (EAR) following the Second Industrial Revolution (~1870) and the opening of the Suez Canal. In the North, where industrial activities become prevalent, we observe an increase in the mean EAR of Fe, Cd, V, Zn, Cu, and Cr from 4.56% to 17.6%, with positive slope change rates ranging from 332% (Fe) to 1003% (Cu). Conversely, in the South, we observe a decline in the mean EAR of Mg, total N, total organic C, and Ca from -8.5% to -17.8%, with negative slope change rates ranging from -83% (Ca) to -13980% (Mg). The results reveal the increasing accumulation of trace metals from human activities in recent decades in the North, whereas the South is experiencing a decline in nutrient input from the Indian Ocean associated with ocean warming. These two challenges may be synergistic and have a detrimental effect on the Red Sea ecosystems.

Lionfish was studied in the mesophotic environment. 237 specimens were observed, most in the upper mesophotic zone. Males were larger than females and differences between sexes in growth models were found. Sixteen prey items were identified, the most important being the teleost families Acanthuridae and Monacanthidae, and the crustacean Penaeidae. The mean of δ13C was -17.08 ± 0.36 ‰ and δ15N was 8.68 ± 0.46 ‰, with no differences between sexes. Lionfish occupies a less extensive isotopic niche in mesophotic environment than in shallow sectors; there is an isotopic niche overlap between sexes. Likewise, lionfish has specialized trophic habits. All specimens were mature and in females regression phase predominated. In females, condition factor (CF), gonadosomatic index (GSI) and hepatosomatic index (HSI) increased with gonadal development, reaching peak in the active spawning phase, and decreasing in regression. Males had a condition factor similar to spawning females, but IGS and IHS were lower

The Cerro Matoso deposit, one of the largest open-pit ferronickel mines in the world is formed by a sedimentary succession on top of an abducted ultramafic body that makes part of the Cauca ophiolite complex. The set of rocks was accreted in northwestern Colombia during the Cretaceous and exposed to weathering processes during the last Andean Orogeny. Sediment samples were collected and studied using petrographic microscopy, SEM, EPMA, ICP-MS, XRF, and oxygen as well as carbon isotopes analyses. Oxygen isotope results reflect pore-water temperatures reaching up to 130°C during mineral precipitation, which are consistent with serpentinization-derived fluids of mantle rocks that may be related to deep-sea hydrothermal activity. Negative δ13C values (–27.1 to –1‰ V-PDB) in bulk samples of the tabular succession correlate with the δ13C range of methane from modern serpentinite-derived fluids. The REE/Fe data (ratio

The hypothesis that seaweed farming contributes to carbon burial below the farms was tested by quantifying burial rates in 20 seaweed farms distributed globally, ranging from 2 to 300 years in operation and from 1 ha to 15,000 ha in size. This involved combining analyses of organic carbon density with sediment accumulation rate in sediments below seaweed farms relative to reference sediments beyond the farm and/or prior to the farm operation. One in every four farms sampled was set over environments that export, rather than retain materials. For the farms that were placed over depositional environments, where sediment accumulation could be quantified, the thickness of sediment layers and stocks of carbon accumulated below the farms increased with farm age, reaching 140 ton C ha-1for the oldest farm, and tended to exceed those in reference sediments beyond the farm and/or prior to the operation of the farms. Organic carbon burial rates in the farm sediments averaged (± SE) 1.87 ± 0.73 ton CO2equivalent (CO2-eq) ha-1year-1(median 0.83, range 0.10 – 8.99 ton CO2-eqha-1year-1), twice the average (± SE) burial rate in reference sediments (0.90 ± 0.27, median 0.64, range 0.10-3.00 ton CO2-eqha-1year-1), so that the excess organic carbon burial attributable to the seaweed farms averaged 1.06 ± 0.74 ton CO2-eqha-1year-1(median 0.09, range −0.13-8.10 ton CO2-eqha-1year-1). This first direct quantification of carbon burial in sediments below seaweed farms confirms that, when placed over depositional environments, seaweed farming tend to sequester carbon in the underlying sediments, but do so at widely variable rates, increasing with farm yield.

Scalloped hammerhead shark, Sphyrna lewini, is considered a generalist predator, showing individual specializations and different trophic levels. This species inhabits both oceanic islands and coastal nursery areas in the eastern tropical Pacific (ETP) Ocean. Existing trophic ecology studies on S. lewini have been focused on stomach contents. This study provides new insights into its foraging preferences, habitat use, and trophic position, using stable isotope analysis (SIA) of muscle tissue. Stable isotope signatures of δC and δN were determined in S. lewini muscles (n = 29) from the Ecuadorian Pacific in 2013. Trophic position (TP), isotopic niches, and overlap of S. lewini were estimated by sex, age, and maturity stages to infer their dietary habits throughout life stages. SIA revealed complex movement patterns related to sex and age classes of S. lewini, highlighting high degrees of dietary plasticity and habitat use, with a stronger relation to coastal regions than previously reported. This study provides crucial information regarding essential areas and the related migration behavior of S. lewini, with important implications for their conservation and management in the ETP., Special thanks to the artisanal fishermen communities who supported the sampling for this project and a great acknowledgement to the Fundación Alium Pacific for logistical support and the Instituto Andaluz de Ciencias de la Tierra in Granada (CSIC-UGR), Spain, for the technical assistance in the analysis. Thanks to D. Edgar for editing our text for English. We thank the anonymous reviewers for improving the manuscript.

Deep-sea hypersaline anoxic basins are polyextreme environments in the ocean’s interior characterized by the high density of brines that prevents mixing with the overlaying seawater, generating sharp chemoclines and redoxclines up to tens of meters thick that host a high concentration of microbial communities. Yet, a fundamental understanding of how such pycnoclines shape microbial life and the associated biogeochemical processes at a fine scale, remains elusive. Here, we applied high-precision sampling of the brine–seawater transition interface in the Suakin Deep, located at 2770 m in the central Red Sea, to reveal previously undocumented fine-scale community structuring and succession of metabolic groups along a salinity gradient only 1 m thick. Metagenomic profiling at a 10-cm-scale resolution highlighted spatial organization of key metabolic pathways and corresponding microbial functional units, emphasizing the prominent role and significance of salinity and oxygen in shaping their ecology. Nitrogen cycling processes are especially affected by the redoxcline with ammonia oxidation processes being taxa and layers specific, highlighting also the presence of novel microorganisms, such as novel Thaumarchaeota and anammox, adapted to the changing conditions of the chemocline. The findings render the transition zone as a critical niche for nitrogen cycling, with complementary metabolic networks, in turn underscoring the biogeochemical complexity of deep-sea brines., This research was supported by King Abdullah University of Science and Technology through baseline funding and Red Sea Research Center competitive fund to DD. We thank the crew of R/V Thuwal and CMOR for their support in sampling the brines, especially Brian Hession and Thomas Hoover. We also thank personal of the KAUST Bioscience Core Lab for their assistance with sequencing.

Although Pliocene palaeosols can supply palaeoclimate information and help to disentangle stratigraphic reconstructions, soils are sparsely represented in global datasets for Pliocene climate. Pliocene was characterised by global mean annual temperatures 2–4 °C warmer than today, representing an analogue for future climate prevision. We aimed, thus, to investigate palaeosols as suitable archives for reconstructing geomorphic processes, ecosystems and climate patterns in the Pliocene.We compared the palaeosol record stored in Zanclean and Piacenzian successions locate in central and southern Tuscany, respectively. Palaeosol morphological features observed in the field were used for the sequence-stratigraphic interpretation. To qualitatively evaluate soil development, we considered the time needed to attain various soil properties. Pedogenetic processes and the intensity of weathering were also quantified by applying a range of proxies based on geochemical analyses. Climofunctions based on major element ratios were used to estimate mean annual palaeoprecipitation (MAP). Carbon and oxygen isotopes analysis were performed on carbonate nodules, to verify their pedogenic origin and as a proxy for palaeovegetation and palaeotemperatures.Though all soils are unconformities in the record, the rank and type of unconformity were defined in detail, to precisely place the soil formation time within the sedimentary sequence and to correlate soil-forming intervals with general environmental changes. Then, soil characteristics were interpreted, considering the geomorphological setting reconstructed by the stratigraphic and sedimentological analysis.The Zanclean-age soils represent a presumably long-time span, likely a few thousand years, and exhibit strong redoximorphic features such as low-grade plinthite, suggesting that they developed in intervals of humid climate. The mid Piacenzian-age soils represent rhythmic and short intervals of pedogenesis, which correlate to sea level highstands. The main characteristics of palaeosols are due to clay shrink-swell properties (vertic) and carbonate translocation (calcic). Calcic features were interpreted as recording the duration of pedogenesis and thus of the sedimentary hiatuses, suggesting a range of development from 1,000 to 10,000 years. These soil features and the isotopic proxies converge towards indicating a highly seasonal rainfall pattern. This inference matches the sedimentological facies, which point to sediment transport and deposition from highly laden flood flows, recalling the sedimentary dynamics of seasonal fluvial systems. The hypothesis of a very high degree of rainfall seasonality would match well with existing palaeoclimatic records for the Mediterranean Middle Pliocene Warm Period (MPWP), and could shed light on certain unusual features in such records.Comparing soils developed in the Early and in the Late Pliocene, the MAP estimates confirm the differences in climate condition which likely led to the divergent pedogenesis pathways. Furthermore, the palaeotemperatures estimated from the oxygen isotopic composition of pedogenic carbonates within Piacenzian calcic horizons, point to values matching the modelled temperatures for the MPWP.

To gain a better understanding on the trophic ecology of New Granada sea catfish, Ariopsis canteri, and their linkage to mangroves, nitrogen and stable carbon isotopes (δN and δC), as well as Bayesian mixing models, were used to explore trophic dynamics and potential ontogenic feeding shifts across different size classes: class I (8–20 cm), class II (21–32 cm) and class III (>32 cm). The study area was the estuary of the Atrato River Delta, where information about fish ecology is scarce. The δC of size class I was lower (mean ± s.d. = −24.96 ± 0.69‰) than that of size classes II (−22.20 ± 0.90‰) and III (−22.00 ± 1.96‰). The δN of size class I was lower (mean ± s.d. = 8.50 ± 0.67‰) than that of size classes II (9.77 ± 0.60‰) and III (10.00 ± 0.66‰). Body size was positively and significantly correlated to δN and δC. Individuals with L > 32 cm presented the highest estimated trophic position (3.8). Five-source mixing models indicated that for class I, the mean estimated contribution of macroalgae was the highest (6%–57% c.i.), and for classes II and III, the mean estimated contribution of macrophytes was the highest (3%–53% c.i. and 4%–53% c.i., respectively). Ontogenetic feeding shifts of A. canteri were confirmed evidencing decreasing intraspecific competition between small and large individuals. Results suggest that mangroves are a nursery and feeding ground habitat for this species and that mangroves support A. canteri mainly due to the substrate/habitat that supports sources in the food webs. These results can be used in ecosystem-based fishery management focused on the protection of extensive mangrove areas in the southern Caribbean Sea., We thank the project LOPEGU and funding by Sistema General de Regal?as, Gobernaci?n de Antioquia, and Universidad de Antioquia (agreement number: 4600000983). We thank the Consejo Comunitario Mayor de Bocas del Atrato y Leoncito for their hospitality, granting us access to their territory, supporting fieldwork and sharing traditional and local ecological knowledge. We thank A. Sep?lveda-Lozada for helpful comments on isotope fractionation and mixing models. We thank F. Arenas for English-language revision and also thank the anonymous reviewers. L.A.S. acknowledges the financial support from the Doctoral Fellowship Programme by the Administrative Department for Science, Technology, and Innovation (Departamento Administrativo de Ciencia, Tecnología e Innovación) COLCIENCIAS.

The economic and political disruption following the collapse of the Roman Empire is an important moment for the cultural and biological history of Western Europe. One of the trends associated this socioeconomic change is the reuse of Roman public monuments for different purposes including funerary ones. The cultural meaning of this practice, occasionally described throughout Europe, is however still unclear. Here, we present a study of a group of burials (N = 10) recently discovered in the Roman amphitheatre (Arena) of Verona (Northeastern Italy) and dating to Early Middle Ages (8 and 9 century AD). Specifically, we address the following research questions: (1) What depositional events are responsible for the observed stratigraphic sequence? 2) Which demographic composition and health condition characterize this sample? (3) What kind of diet characterized these individuals? In order to address these questions, we performed an osteological and isotopic (δC and δN) study of the skeletal evidence for the assessment of palaeopathological and dietary patterns and a histological analysis for the refinement of age at death and the calculation of the minimum number of individuals (MNI). A C study was also performed in order to better define the depositional sequence of these individuals. The results, besides being among the first palaeodietary data for Early Middle Ages in this region, highlight: (a) the funerary use of this location for at least one century; (b) an MNI of 10 individuals of both sexes and different age classes, featuring relatively high frequencies of unspecific stress markers (porotic hyperostosis and linear enamel hypoplasia) and trauma, and (c) a diet characterized by a consistent contribution of C plants and a good access to animal proteins. These results suggest a long-spanning practice and the absence of any selectivity in the choice of these individuals. Finally, isotopic data align with previous studies on Bronze and Iron Age samples confirming a long tradition of alimentary exploitation of C plants in this area., Projects RNM‐8011 and the research 584 group RNM‐309 (Junta de Andalucía, Spain)

Arctic calcifiers are believed to be particularly vulnerable to ocean acidification as the Arctic already experiences low carbonate saturations states due to low temperature and high inputs of freshwater. Here, we report the finding of dense beds of Mytilus growing in tidal lagoons and river mouths, where the availability of carbonate ions is remarkably low Ω < 0.5. Although these Mytilus grow in the intertidal zone, and therefore are covered by seawater during high tide, δO isotopes of shell carbonate were low − 2.48 ± 0.05‰, confirming that their shells were deposited under low salinity conditions, i.e., reflecting a contribution from O-depleted freshwater. δO isotopes of shell carbonate became heavier with increasing salinity, with mean values of − 0.74 ± 0.96‰ for Mytilus growing in tidal pools. We calculated, based on δO isotopic composition standardized to a common temperature, that freshwater accounted for 7% of the carbonate oxygen in the shells of Mytilus at the habitats with near full-strength seawater salinity compared with 25% in shells collected at sites temporarily exposed to freshwater. The composition of the periostracum revealed a trend for shells from river mouths and brackish tidal lagoons to be more depleted in polysaccharides than shells exposed to higher salinity. We conclude that the high food supply associated with riverine discharge allows Mytilus to cope with the low saturation states by using energy to calcify and modify their periostracum to protect the shells from dissolution. These findings suggest that Arctic Mytilus are highly resistant to low saturation states of carbon minerals if supplied with sufficient food., This research was funded by a grant from The Carlsberg Foundation grant number CF15-0639

The previously uncharted Afifi brine pool was discovered in the eastern shelf of the southern Red Sea. It is the shallowest brine basin yet reported in the Red Sea (depth range: 353.0 to 400.5 m). It presents a highly saline (228 g/L), thalassohaline, cold (23.3 °C), anoxic brine, inhabited by the bacterial classes KB1, Bacteroidia and Clostridia and the archaeal classes Methanobacteria and Deep Sea Euryarcheota Group. Functional assignments deduced from the taxonomy indicate methanogenesis and sulfur respiration to be important metabolic processes in this environment. The Afifi brine was remarkably enriched in dissolved inorganic carbon due to microbial respiration and in dissolved nitrogen, derived from anammox processes and denitrification, according to high δN values (+6.88‰, AIR). The Afifi brine show a linear increase in δO and δD relative to seawater that differs from the others Red Sea brine pools, indicating a non-hydrothermal origin, compatible with enrichment in evaporitic environments. Afifi brine was probably formed by venting of fossil connate waters from the evaporitic sediments beneath the seafloor, with a possible contribution from the dehydration of gypsum to anhydrite. Such origin is unique among the known Red Sea brine pools., This research was funded with King Abdullah University of Science and Technology funding through baseline funding and Red Sea Research Center competitive fund to C.M.D. and D.D. We thank J.C. Santamarina, M. Terzariol, K. Pigeon, A. Granados and J.M. Arrieta, and the crew of R/V Thuwal for their help.

Coastal areas are particularly important, as their shallow waters commonly correspond to nursery areas for many species. Unfortunately, these habitats also support many commercial fisheries which overlap with nursery areas and can represent a risk to numerous shark species, including Sphyrna lewini which frequent both coastal waters and offshore islands throughout their lifecycle and are affected by the high fishing activity in coastal areas, particularly during their early life stages. For this reason, it is imperative to identify and establish connectivity between key habitats during their lifecycle to improve conservation strategies. This study provides the first evidence about habitat use and migration corridors between oceanic aggregation zones and coastal areas of the Colombian Pacific, which constitute important habitats for S. lewini. A total of five S. lewini neonates were sampled in the Sanquianga National Natural Park coastal area: the individuals ranged from 48.2 to 52.8 cm in total length and were obtained by artisanal fishermen. Our δC (− 16.3 ± 0.16‰) and δN (15.9 ± 0.11‰) values were similar to those obtained from specimens from the Malpelo isospace (δC: − 16.3 ± 0.1‰ and δN: 15.9 ± 0.11‰). Our isotopic results showed significant use and connectivity between both marine environments (oceanic and coastal areas), the extent of which depended on shark maturity stages, providing evidences of the trophic links of S. lewini between Malpelo waters and the Sanquianga National Natural Park coastal area. Therefore, this study highlights the importance of both habitats in the lifecycle of S. lewini and provides preliminary inferences about S. lewini ecology and habitat preference representing a baseline for further research., We thank the Parques Nacionales Naturales de Colombia, to all teams of the Malpelo FFS, Sanquianga NNP, and Fundación Malpelo y Otros Ecosistemas Marinos for their support in collecting the samples and to the Fundación Alium Pacific for logistical support and the Instituto Andaluz de Ciencias de la Tierra in Granada (CSIC-UGR), Spain, for technical assistance in the analysis. We are especially thankful to the fishing communities who supported the sampling for this project. We would also like to thank the anonymous reviewers for their comments, which improved the manuscript. Thanks go to Daniel Edgar for editing the text for English.

Sharks are top predators and play an important role in the regulation of marine ecosystems at lower trophic position. Mustelus californicus, Sphyrna zygaena, and Isurus oxyrinchus prove to be important fishery resources along the western coast of Baja California Sur and cohabit the same coastal areas, probably sharing resources. However, our knowledge about ecological dynamics of multiple species coexisting and sharing similar habitat resources is still limited, particularly for predators such as sharks. Therefore, this study focuses on the analysis of trophic ecology of the sharks species, using carbon (

Spatial variations of denitrification activity and the relative importance of controlling factors were determined using the isotope pairing technique in a seepage chain of Mediterranean flowthrough lakes (Ruidera lakes) and within a given lake in the chain (Colgada lake), all receiving extremely high nitrogen inputs. The range of denitrification rates measured (28-155 ¿mol N m-2 h-1) were comparable with rates measured with isotope pairing in other freshwater systems. While the bulk of total denitrification was mostly based on NO3- from the overlying water, coupled nitrification-denitrification seemed to be lower in all Ruidera lakes. At the regional scale, i.e. lake district, inter-variability in denitrification (CV = 37 %) was lower than the intra-variability observed in a single lake (CV = 54 %). In fact, a preliminary meta-analysis of data from published studies suggested that denitrification rate variabilities did not differ statistically between the environmental and regional scales. Dissolved oxygen concentration, dissolved organic carbon content and nitrate from the overlying water were found to be the most important factors affecting the spatial heterogeneity of denitrification rate in the lake complex. At the single-lake scale, only phosphorus explained the variability of denitrification rates observed along its main axis. Our study emphasizes the significance of hotspots in denitrification processes, but also highlights the need for further studies on spatial denitrification given that fact that conflicting controlling factors have been found at different scales. To spatially measure denitrification is complicated due to the intrinsic difficulties of the incubation process and hotspots, which makes modelling indispensable., [ES] Mediante la técnica del par isotópico, estudiamos las variaciones espaciales de la actividad desnitrificante y la importancia relativa de sus factores de control en una cadena de lagos mediterráneos de tipo fluvial (lagunas de Ruidera) y en un lago concreto dentro de la misma (Laguna Colgada), todos los cuales reciben cargas elevadas de nitrógeno. El rango de las tasas medidas mediante dicha técnica fue comparable (28-155 µmol N m-2 h-1) al registrado en otros ambientes dulceacuícolas. Gran parte de las tasas se debieron al nitrato presente en el agua sobrenadante al sedimento (62-83 %), resultando de menor importancia los procesos acoplados de nitrificación-desnitrificación en todos los lagos estudiados. A escala del conjunto lacustre, la variabilidad del proceso fue inferior (CV = 37 %) a la presente en un único lago (CV = 54 %). En relación con esto, un meta-análisis preliminar de la variabilidad de la desnitrificación en distintos limnoambientes reveló que no había diferencias significativas entre la escala del ecosistema individual y la regional. Las concentraciones de oxígeno disuelto, carbono orgánico disuelto y nitrato en el agua sobrenadante fueron los factores fundamentales que controlaron las tasas de desnitrificación en el conjunto de lagos, mientras que en la laguna Colgada solo el ortofosfato explicó la variabilidad del proceso registrada en su eje principal. Este estudio recalca la importancia de los micrositios más favorables (hotspots) para el proceso de desnitrificación, pero también apoya la necesidad de más estudios sobre el tema porque los factores que lo controlan a distintas escalas espaciales difieren entre estudios. Las dificultades intrínsecas a la incubación y a la existencia dichos micrositios para medir espacialmente este proceso mediante cualquier técnica hacen imprescindible la modelización del mismo, We gratefully acknowledge the technical staff of Lagunas de Ruidera Natural Park for assistance and lake level data. We are also grateful to the Guadiana Water Authority for data on water discharge to Ruidera lakes. Field and lab help provided by Jos? Mar?a Alonso, Eva L?pez-Del-gado and Meritxell Plensa is also acknowledged. Julio Mateo is thanked for constructing the incubators for the isotope pairing technique improving an earlier design by the Swiss EAWAG (Prof. Bernhard Wehrli). This study has been supported by a predoctoral fellowship to E. Piña-Ochoa and the REN-2002-00558 and CGL-2006-2346/HID Projects of the Spanish Ministry of Education and Science.

Changes in feeding habits during ontogeny show that organisms can present shifts in foraging behavior during their life cycle, which can alter local trophic dynamics. Therefore, describing diet across species ontogeny clarifies the ecological niche and ecosystem role of marine predators. In this study, diet tracers (stable isotope analysis) were analyzed in 16 scalloped hammerhead sharks Sphyrna lewini, using δ13C and δ15N values of collagen in vertebral cross-sections to reconstruct diet across their ontogeny. Our results suggest that S. lewini occupies a broad isotopic niche due to the consumption of prey belonging to different trophic levels (δ15N: 7.6-13.0‰) of the food chain in both coastal and oceanic zones (δ13C: -17.2 to -14.1‰) during their lifetime. Accordingly, ontogenetic changes in diet and habitat use were suggested by differences in δ13C and δ15N across age groups, indicating high consumption of coastal prey at 0-2 yr, oceanic prey at ~2-4 yr, a shift to high coastal prey at >4 yr, and a shift to high coastal prey, along with the consumption of prey from multiple trophic levels through feeding ontogeny (estimated trophic position: 2.9-6.5). This study showed migration from coastal to oceanic zones in juvenile S. lewini, and their return to coastal habitats as adults, potentially related to the use of coastal zones (i.e. mangroves) in the Eastern Tropical Pacific, both as important feeding areas for neonates and as feeding and breeding grounds for adults.

Isotopic values of two Caribbean sharpnose shark Rhizoprionodon porosus litters (Poey, 1861) with two and three embryos and one litter of 11 smalltail shark Carcharhinus porosus embryos showed enriched N and C compared to their mothers. In R. porosus, embryonic isotope values were 3.06 ± 0.07‰ and 0.69 ± 0.15‰ greater than their mothers' for δN and δC, respectively, whereas in C. porosus, δN and δC were 1.79 ± 0.09‰ and 1.31 ± 0.17‰ greater in embryos than their mothers., We would like to thank Edward, Darwin and Isnaldo who made collection of samples and their processing at the port possible. Financial and logistical support for this project was provided by Anadarco and the Autoridad Nacional de Acuicultura y Pesca, through Fundación Fauna Caribe Colombiana under an agreement with the Universidad de Bogotá Jorge Tadeo Lozano under the Programa de Observadores Pesqueros de Colombia.

Objectives: Gender differentiation can influence the diet, physical activity, and health of human populations. Multifaceted approaches are therefore necessary when exploring the biological consequences of gender-related social norms in the past. Here, we explore the links between diet, physiological stress, physical activity, and gender differentiation in the Medieval Islamic population of La Torrecilla (Granada, Spain, 13th–15th century AD), by analyzing stable isotope patterns, stature, and long bone diaphyseal measurements. Materials and Methods: The sample includes 96 individuals (48 females, 48 males) classified as young and middle adults (20–34 and 35–50 years of age respectively). Diet was reconstructed through the analysis of δ13C and δ15N. Stature, humeral and femoral diaphyseal shape and product of diaphyseal diameters served as proxies of physiological stress and physical activity. Results: Isotopic ratios suggest a substantial dietary contribution of C4 plants (e.g., sorghum, millet), a variable access to animal proteins, and no differences between the sexes. Sexual dimorphism in stature derives from a markedly low female stature. Long bone diaphyseal properties suggest that men performed various physi cally stressful activities, whereas women were involved in less physically demanding activities (possibly related to household work). Discussion: Gender differentiation in La Torrecilla was expressed by a possibly differ ential parental investment in male versus female offspring and by culturally sanc tioned gender differences in the performance of physical tasks. Diet was qualitatively homogenous between the sexes, although we cannot rule out quantitative differ ences. Our results shed new light on the effects of gender-related social norms on human development and lifestyle., Proyecto HAR2016-75788-P del Ministerio de Ciencia y Competitividad del Gobierno de España

On the west coast of Baja California Sur, the shark species Mustelus henlei, Carcharhinus falciformis, Prionace glauca, Isurus oxyrinchus, and Sphyrna zygaena are of economic importance and coexist in the same ecosystem. However, the trophic role of each species in this ecosystem is poorly understood. Stable isotopes of nitrogen and carbon (δN, δC) have been used as an indicator of trophic habitat at different time scales, showing the foraging area and trophic position of sharks. The isotopic values in the muscle and blood of five shark species were analyzed on the southwest coast of Baja California Sur. The isotopic values of P. glauca, S. zygaena and C. falciformis indicated a trophic habitat in oceanic areas, which is a characteristic of these species considering that they feed mainly on mesopelagic cephalopods; whereas M. henlei and I. oxyrinchus showed a benthic diet in oceanic waters. The highest trophic position based on muscle and blood results was in S. zygaena, while the lowest trophic position was in the tissue of C. falciformis, probably because this species feeds on a higher proportion of the crustacean Pleuroncodes planipes. Some of these species share prey and forage in the same area., The authors would like to thank and appreciate CONACyT (Consejo Nacional de Ciencia y Tecnología) and the Instituto Politecnico Nacional fellowships (COFAA, EDI) for their support with this project. Special thanks also to the project of CONACYT, Mexico No. 253700 and SIP-IPN, Mexico (grant number 20170563). We thank to Dr. Darren Whitehead for help in the English edition.

This article presents for the first time a large dataset of rainfall isotopic measurements (d18Op and d2Hp) sampled every day or every two days from seven sites in a west-to-east transect across northern Spain for 2010–2017. The main aim of this study is to: (1) characterize rainfall isotopic variability in northern Spain at daily and monthly time scales, and (2) assess the principal influencing factors determining rainfall isotopic variability. This comprehensive spatio-temporal approach allows exploring the role of air mass source in determining the isotopic composition of rainfall in northern Iberia by using back-trajectories; Atlantic fronts are found to be the dominant source of northern Iberia rain events studied. The relative role of air temperature and rainfall amount in determining the stable isotope composition of precipitation changes along the west-to-east transect. Air temperature appears to be the most significant influence on d18Op at daily and monthly time scales with the highest air temperature-d18Op dependency found for the Pyrenean station while a few sites in the transect show a significant negative correlation with precipitation amount. Distance from the coast, site elevation, and moisture source region (Atlantic versus Mediterranean) also significantly modulate the d18Op values and ranges but the type of precipitation (convective vs frontal rainfall) plays a key control, with convective rainfall associated with higher d18Op values. This dataset of the rainfall isotopic composition represents another step forward towards developing a more detailed, mechanistic framework for interpreting stable isotopes in rainfall as a palaeoclimate and hydrological tracer.

The results of the isotopic analyses performed on human remains from the Chalcolithic necropolis of Los Millares are presented in this paper. These are contextualized chronologically by a series of radiocarbon dates and, a review of the graves’ relative chronology. The dates show the megalithic necropolis was in use all along the occupation period of Los Millares, at least from 3100/3000 to 2200/2100 cal BC. The isotopic analysis results support the proposals for increasing aridity from 2400/2300 cal BC onwards. Diet is mainly based on land resources, proteins being usually taken from herbivores. However, a certain variability is found among sampled individuals because some of them may have consumed others products., Se presentan en este estudio los resultados de los análi­sis isotópicos realizados sobre una muestra de restos huma­nos de la necrópolis calcolítica de Los Millares. Para proce­der a su discusión se ha realizado previamente su contextualización cronológica a partir de una serie de data­ciones radiocarbónicas y la revisión de la cronología relati­va de los sepulcros. Las dataciones muestran el uso de la necrópolis megalítica durante todo el periodo de ocupación de Los Millares, al menos desde 3100/3000 hasta 2200/2100 cal AC. Los resultados del análisis isotópico apoyan las pro­puestas sobre un incremento en la aridez desde el 2400/2300 cal AC. Además, en una dieta dominada por los recursos terrestres en la que las proteínas suelen proceder del consu­mo de herbívoros, existe una cierta variabilidad con indivi­duos que pueden haber consumido otros recursos, Este trabajo se ha realizado en el marco de los proyectos: “Dieta y movilidad en la Prehistoria Reciente de Andalucía. Un estudio de la jerarquización social a partir del registro funerario (P12-HUM-1510, Consejería de Economía, Innovación, Ciencia y Empleo de la Junta de Andalucía) y “Estrategias agropecuarias y consumo en la Edad del Bronce del sur de la península ibérica. Análisis de plantas, animales y restos humanos” (HAR2016- 80057-P, Ministerio de Economía y Competitividad).

Rationale: Stable carbon isotope ratios have many applications in natural sciences. In the first worldwide interlaboratory proficiency test, the discrepancies in measured δC values of natural waters were up to σ = ±3‰. Therefore, we continued the investigation on the analytical data quality assurance of individual laboratories and internal consistency among laboratories worldwide. Methods: We designed and performed an interlaboratory comparison exercise for δC analyses of ten water and two solid samples (NaCO, CaCO), including two synthetic samples prepared by dissolving the carbonates individually. Three laboratories analyzed an additional sample set to assess solution stability, at least one month after the first set analysis period. The δC values were measured using dual inlet isotope ratio mass spectrometry (DI-IRMS) or continuous flow (CF)-IRMS. Results: The δC values of solid NaCO and its aqueous solution were −5.06 ± 0.21‰ and 5.32 ± 0.24‰, respectively, while the δC value of solid CaCO was −4.49 ± 0.93‰. Similarly, the lake water has a consistent value (2.45 ± 0.19‰). The δC values of geothermal water have a wide dispersion among individual laboratory measurements and among those of different laboratories; however, a trend exists in the δC values measured at the three sampling points of each well. Conclusions: The δC values of solid NaCO and its solution, and lake water (i.e. DIC concentration samples >100 mg/L carbon) are consistent among all the participating laboratories. The dispersion in the δC values of solid CaCO is associated with its lower chemical affinity than that of NaCO. The poor reproducibility in the δC values of geothermal fluids, collected at three points of a geothermal well, despite overall consistent trends regarding their collection points suggests inadequate sample handling (atmospheric CO exchange) and/or inappropriate analytical approaches (incomplete HPO acid reaction)., The authors appreciate the authorities of INEEL for organizing the proficiency test as well as the assistance from coordinating members of each participating laboratory to undertake the comparison exercise. Financial support for sampling (travel grant, material and courier services expenses) was provided by the “Secretaría de Energía” (SENER) and “Consejo Nacional de Ciencia y Tecnología” (CONACYT) under the project CeMIEGeo‐PLabs. They also thank the authorities of the “Comisión Federal de Electricidad” (CFE), especially Ing. Carlos Sanchez Cornejo, manager of “Gerencia de Proyectos Geotermoelectricos‐CFE”, and Biól. Emigdio Casimiro Espinoza, manager of Los Azufres Geothermal Field (LAGF), who permitted and facilitated the sampling of two production wells at LAGF. The constructive comments of anonymous reviewers helped to improve the final version of this manuscript.

Small dogs as pets, objects of affection and special consideration by their owners, are known in the Western Mediterranean since classical Antiquity through texts, epigraphy and iconography. The study of a small-sized canid with a brachycephalic skull discovered in a cemetery, among other specimens, in the southern Hispania yields new interpretations regarding the relationships between dogs and humans at the outset of the Common Era in the western Roman world and sheds light on how to evaluate their symbolic implications in funerary rites. The physical characteristics of these specimens were analysed through morphological, osteometric, palaeopathological and biochemical isotopes methods. The findings represent a step forward in the understanding of the everyday life, mobility and diet of dogs, as well as the cause of their death which, in the case of the small-sized specimen, appears to correspond to a deliberate sacrifice., This study was financed by the Consejería de Innovación y Empresa-Junta de Andalucía (project HUM-061658) in the framework of the State Plan for Scientific and Technical Research and Innovation 2013-2016 (Juan de la Cierva-Incorporación) (RMMS)

The concentration of CH in water was measured along five transects in the Gulf of Cadiz (Trafalgar, Sancti Petri, Guadalquivir, Tinto - Odiel and Guadiana) during four cruises throughout the months of March, June, September and December 2016. For two of the cruises water overlying three mud volcanoes situated in the Gulf of Cadiz were also sampled (San Petersburgo, 860 m; Pipoca, 460 m; and Anastasya, 500 m. In addition, the stable carbon isotopic compositions of dissolved CH (δC) were measured in the study area in June and December 2016. The mean CH value for the whole water column was 10.5 ± 4.3 nmol L, with large spatial and temporal variations. The highest values were found in June 2016 and the lowest in March 2016. In surface waters, the mean dissolved methane concentration was of 9.6 ± 2.6 nmol L. In most of the sampling area, high concentrations of CH were found in subsurface waters at depths close to the thermocline and at the coastal stations. The highest concentrations were obtained from the bottom waters above the Anastasya mud volcano (125 nmol L). The stable carbon isotope compositions ranged between - 29.2 and - 58.4‰, and the least negative values were associated with the highest CH concentrations in samples from above the mud volcanoes, related to thermogenic values. The sea-air fluxes of CH ranged from 12.4 to 37.7 μmol m d, showing that the study area acts as a source of CH to the atmosphere., A. Sierra was financed by the Spanish Ministry of Education with a FPU fellowship (FPU2014-04048) and M.D. Jiménez-López was financed by the University of Cádiz with a FPI fellowship (FPI-UCA). We thank the crews of the R/V's Angeles Alvariño and Ramon Margalef for their assistance during field work. This study was supported by the Spanish CICYT (Spanish Program for Science and Technology) under contract CTM2014-59244-C3-1-R.

This study investigates the possible involvement of maize aquaporins which are regulated by arbuscular mycorrhizae (AM) in the transport in planta of ammonium and/or urea under well-watered and drought stress conditions. The study also aims to better understand the implication of the AM symbiosis in the uptake of urea and ammonium and its effect on plant physiology and performance under drought stress conditions. AM and non-AM maize plants were cultivated under three levels of urea or ammonium fertilization (0, 3 &micro, M or 10 mM) and subjected or not to drought stress. Plant aquaporins and physiological responses to these treatments were analyzed. AM increased plant biomass in absence of N fertilization or under low urea/ ammonium fertilization, but no effect of the AM symbiosis was observed under high N supply. This effect was associated with reduced oxidative damage to lipids and increased N accumulation in plant tissues. High N fertilization with either ammonium or urea enhanced net photosynthesis (AN) and stomatal conductance (gs) in plants maintained under well-watered conditions, but 14 days after drought stress imposition these parameters declined in AM plants fertilized with high N doses. The aquaporin ZmTIP1, 1 was up-regulated by both urea and ammonium and could be transporting these two N forms in planta. The differential regulation of ZmTIP4, 1 and ZmPIP2, 4 with urea fertilization and of ZmPIP2, 4 with NH4+ supply suggests that these two aquaporins may also play a role in N mobilization in planta. At the same time, these aquaporins were also differentially regulated by the AM symbiosis, suggesting a possible role in the AM-mediated plant N homeostasis that deserves future studies.

This study presents the isotopic ratios, radiocarbon datings, and anthropological analyses of five (N = 5) Early Copper Age individuals from two archaeological sites (Arruzafa and Iglesia Antigua de Alcolea) of the Middle Guadalquivir Valley near the city of Córdoba (Spain). Four had been buried in the same grave, possibly in a single event or in a very short time lapse. The collagen residue analyses of the individuals offer δC values ranging between −20.08 and −18.4 and δN values between 8.57 and 11.15. The findings indicate that the infant and the elderly had, respectively, the richest and poorest animal protein diets, the first likely as a result of nursing. The combined study of these five individuals offers an interesting approach to a small segment of population of the farming communities occupying this territory at the beginning of the Copper Age (3200–3000 cal BC)., Consejería de Innovación y Empresa-Junta de Andalucía, Grant/Award Number: HUM-061658

Highly acidic phosphogypsum wastes with elevated potential for contaminant leaching are stack-piled near coastal areas worldwide, threatening the adjacent environment. Huge phosphogypsum stacks were disposed directly on the marshes of the Estuary of Huelva (SW Spain) without any impermeable barrier to prevent leaching and thus, contributing to the total contamination of the estuarine environment. According to the previous weathering model, the process water ponded on the surface of the stack, initially used to carry the waste, was thought to be the main washing agent through its infiltration and subsequently the main component of the leachates emerging as the edge outflows. Preliminary restorations have been applied to the site and similar ones are planned for the future considering process water as the only pollution agent. Further investigation to validate the pollution pathway was necessary, thus an evaluation of the relationship between leachates and weathering agents of the stack was carried out using stable isotopes (δ18O, δ2H, and δ34S) as geochemical tracers. Quantification of the contribution of all possible end-members to the phosphogypsum leachates was also conducted using ternary mixing via the stable isotopic tracers. The results ruled out ponded process water as main vector of edge outflow pollution and unveiled a continuous infiltration of estuarine waters to the stack implying that is subjected to an open weathering system. The isotopic tracers revealed a progressive contribution downstream from fluvial to marine signatures in the composition of the edge outflows, depending on the location of each disposal zone within the different estuarine morphodynamic domains. Thus, the current study suggests that the access of intertidal water inside the phosphogypsum stack, for instance through secondary tidal channels, is the main responsible for the weathering of the waste in depth, underlying the necessity for new, more effective restorations plans.

Geothermal activity in the Chilean Southern Volcanic Zone is strongly controlled by the regional Liquine-Ofqui Fault System (LOFS) and the Andean Transverse Faults (ATF). We analyzed fifteen...

In the framework of a natural CO reservoir with CO leakages as an analogue of a failed CO deep geological storage, the current precipitation of travertines and the associated upwelling of CO-rich saline groundwater were analysed. This natural analogue is located in the Gañuelas-Mazarrón Tertiary Basin (SE Spain). The study comprises of the chemistry of both groundwater and travertines, including stable isotopes, mineralogy and petrography of the travertines, all this performed after a review of the geology of the basin. In this sense, the basin gathers the main features of a safe natural CO reservoir in a deep saline aquifer sealed by a thick marl formation. The aquifer was artificially perturbed by the drilling of wells, inducing the travertines precipitation at these water discharge points. Groundwater is saline, slightly acid, oversaturated in aragonite and calcite and with significant concentrations of heavy elements, some of them toxic. From an isotopic viewpoint, the relative constant δC-DIC values suggest that carbon is mainly inorganic in origin with minor organic and mantle contributions. Travertines are basically composed of aragonite or calcite, their precipitation being controlled by a sudden CO degassing and minor biological activity. Their δC signatures indicate that carbon mainly has an inorganic origin, although some contribution of organic carbon must be considered as well. Furthermore, these carbonate deposits did not precipitate in isotopic equilibrium, as determined by δO values. Finally, it is suggested that the appearance of travertines along with their carbon isotopic signatures represent efficient tools for detecting CO leakages from any CO storage site., This work was supported by the Spanish Ministry of Science and Innovation and the EU FEDER funds under award number PSE-120000-2008-6. The authors are very grateful to Miguel Ángel Labajo (CIEMAT) for the SEM analyses, and Luis Gutiérrez and Marta Pelayo (CIEMAT) for the XRD analyses.

The great site of Valencina de la Concepción, near Seville in the lower Guadalquivir valley of south-west Spain, is presented in the context of debate about the nature of Copper Age society in southern Iberia as a whole. Many aspects of the layout, use, character and development of Valencina remain unclear, just as there are major unresolved questions about the kind of society represented there and in southern Iberia, from the late fourth to the late third millennia cal BC. This paper discusses 178 radiocarbon dates, from 17 excavated sectors within the 450ha site, making it the best dated in later Iberian prehistory as a whole. Dates are formally modelled in a Bayesian statistical framework. The bulk of samples were chosen from the varied mortuary contexts, from pits and artificial caves to megalithic tholos tombs, which constitute a major part of the archaeology of Copper Age Valencina. The resulting formal date estimates provide the basis for both a new epistemological approach to the site as well as a much more detailed narrative of its development than previously available. Beginning in the 32nd century cal BC, a long-lasting tradition of simple, mainly collective and often successive burial was established at the site. There is plenty of evidence for a wide range of other activity, but no clear sign of permanent, large-scale residence or public buildings or spaces. Probably by the 30th or 29th century cal BC, a new form of mortuary practice had emerged alongside older traditions, in the shape of the distinctive megalithic tholos tombs, some of which contained exotic and abundant goods accompanying the dead. Though the models lack precision, this phase of showy funerals and social display, perhaps aimed at establishing new forms of descent and social hierarchisation partly based on the manipulation of the past, may not have lasted much beyond the 28th century cal BC. It is possible that activity as a whole had declined before the middle of the third millennium cal BC, and around 2500 cal BC, dated sectors indicate further changes in mortuary practice, with possible single events, containing in one instance signs of defleshing (perhaps associated with violence); by this date, Bell Beaker pottery was present on the site. Major monuments, such as La Pastora and Matarrubilla were probably also late constructions. At least some of the ditches known at the site probably also belong late in the sequence. Overall, a pattern is indicated of initial establishment and consolidation of mortuary tradition, followed by the emergence of the more elaborate tholos architecture and the sometimes exotic contents. Funerary activity probably declined in intensity in the second quarter of the third millennium cal BC but was followed by a resurgence including the construction of the grand tholos of La Pastora in the generations around 2500 cal BC. This resurgence was relatively brief and the intensive funerary activity probably ended during the 24th century cal BC. Results in general support a model of increasingly competitive but ultimately unstable social relations.

We studied an osteological sample from the pre-Roman/Celtic necropolis of Seminario Vescovile of Verona (Italy), dated to the 3rd to 1st century BCE and attributed to the Cenomani Gauls population. The sample is mostly composed of well-preserved infants in their first months and years of life. In this study we combined isotopic (δ15N and δ13C) and anthropological evidence with the aim of investigating infant feeding practices in non-adult samples. 36 non-adults were selected and divided into seven age phases. The isotopic composition of their rib bone collagen was determined and related to the mean values of adults (n = 54) and animals (n = 7). δ15N values ranged between 7.1‰ and 12.9‰ (AIR), with a mean of 10.2‰ (± 1.5‰), while δ13C values ranged between − 20.2‰ and − 9.7‰ (V-PDB), with a mean of − 15.3‰ (± 2.5‰). These results indicate the initiation of transitional feeding around six months. Significantly high δ15N values in some infants up to two years old suggests prolonged breast-milk consumption. In comparison with the δ15N and δ13C data from the adult females (n = 21), considered as potential mothers, these infants clearly show the effect of breastfeeding on trophic level (δ15N enriched between 1.8 and 3.3‰).