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Dietary variability and the degradation and incorporation of macroalgae in key macroinvertebrate consumers were examined (1) in a monitoring field study including a natural attached canopy habitat and an adjacent habitat receiving natural accumulations of detritus, and (2) in a manipulative in situ experiment of macroalgal detritus at two different depths (3 and 6 m) in the archipelago of SW Finland. The monitoring field study, examining species-specific dietary responses across three sampling dates in natural macroalgal stands, showed that a pulse of drifting filamentous macroalgae shaped the dietary compositions of the abundant benthic macroinvertebrate consumers and that accumulations of drifting filamentous macroalgae were rapidly incorporated into the food web through epigrazers. The in situ field experiment simulating a natural accumulation event and the degradation process of Fucus vesiculosus during 60 days showed that algal decomposition progressed relatively slowly at both depths. Detectable increasing incorporation of Fucus-derived matter to epigrazers and detritivorous bivalves occurred after 2−3 weeks, while simultaneously the incorporation of filamentous algae decreased over time. Hence, the ecological role of decomposing F. vesiculosus might be more important in areas where the algal matter can accumulate for several months. The effect of depth influenced the food incorporation of typical epigrazers. The increasing depth from 3 to 6 m lowered the median proportion of Fucus-derived matter incorporated into the macrofauna community approximately by 10% points compared to the shallower depth of 3 m.

1. The change in species richness along elevational gradients is a well-known pattern in nature. Niche theory predicts that increasing species richness in assemblages can either lead to denser packing of niche space (‘niche packing’) or an expansion into its novel regions (‘niche expansion’). Traditionally, these scenarios have been studied using functional traits but stable isotopes provide advantages such as identifying the degree of resource specialisation, or niche partitioning among functionally similar species. 2. In this study, we evaluate the relevance of niche packing versus niche expansion by investigating stable carbon and nitrogen isotopic niche width and overlap among 23 bat species from six functional groups across a 1500 m elevational gradient in the Himalaya. 3. Our results suggest that an increase in species richness in the low elevation is accompanied by small niche width with high overlap, whereas the high elevation assemblage shows large niche width with low overlap among functional group members. At the functional group level, edge-space foraging, trawling, and active gleaning bats have the highest niche width while passive gleaning bats that are only found in high elevations are isotopic specialists showing low overlap with other groups. Edge and open-space foraging bats showed idiosyncratic changes in niche width across elevations. We also find that the niches of rhinolophid bats overlap with edge-space and open-space foraging bats despite their unique functional traits. 4. These results support the idea that at low elevations high species richness is associated with niche packing while at high elevations strong niche partitioning prevails in dynamic and resource-poor environments. We conclude that although high elevation animal assemblages are often ‘functionally underdispersed’, that is show homogenous functional traits, our approach based on stable isotopes demonstrates niche partitioning among such functionally similar species.

Deep-water sharks are among the most vulnerable deep-water taxa because of their extremely conservative life-history strategies (i.e., late maturation, slow growth, and reproductive rates), yet little is known about their biology and ecology. Thus, this study aimed at investigating the trophic ecology of five deep-water shark species, the birdbeak dogfish (Deania calcea), the arrowhead (D. profundorum), the smooth lanternshark (Etmopterus pusillus), the blackmouth catshark (Galeus melastomus) and the knifetooth dogfish (Scymnodon ringens) sampled onboard a crustacean bottom-trawler off the south-west coast of Portugal. We combined carbon and nitrogen stable isotopes with RNA and DNA (RD) ratios to investigate the main groups of prey assimilated by these species and their nutritional condition, respectively. Stable isotopes revealed overall small interspecific variability in the contribution of different taxonomic groups to sharks' tissues, as well as in the origin of their prey. S. ringens presented higher delta N-15 and delta C-13 values than the other species, suggesting reliance on bathyal cephalopods, crustaceans and teleosts; the remaining species likely assimilated bathy-mesopelagic prey. The RD ratios indicated that most of the individuals had an overall adequate nutritional condition and had recently eaten. This information, combined with the fact that stable isotopes indicate that sharks assimilated prey from the local or nearby food webs (including commercially important shrimps), suggests a potential overlap between this fishing area and their foraging grounds, which requires further attention. LA/P/0101/2020; SOSF 501 info:eu-repo/semantics/publishedVersion

Stable isotopes (δ13C and δ15N) were analysed in vertebrae of Scyliorhinus canicula (n=40; 13 males, 27 females) from the central Tyrrhenian Sea to explore a potential trophic shift in relation to sex and maturity condition. Isotopic values were obtained from the centre and the periphery of the vertebra of each individual to test for the effect of maturity condition. The values of δ13C and δ15N showed significant differences between the immature and mature state of the individuals analysed (U’=1392, P

Predatory fish species play a key role in aquatic ecosystems by exerting top-down control on the food web. Also, their intra-guild trophic interactions (i.e. competition) are crucial for the stability of the community. However, most studies focus on adult stages, while juveniles remain poorly studied, although their recruitment is the basis for the maintenance of predator populations. We analysed carbon and nitrogen stable isotopes ratios of the young-of-year of four coexisting widespread predatory fish species (northern pike Esox lucius, European perch Perca fluviatilis, pikeperch Sander lucioperca, and European catfish Silurus glanis), sampled over 3 years in a shallow natural lake. We found that the hierarchy in trophic position between species was consistent across years and similar to that known for adults, but with large variations around a general pattern: pike and pikeperch tended to occupy the highest trophic positions while perch occupied the lowest, and catfish had very varying positions. Species partitioned their niches to decrease interspecific competition, but with some occasional overlaps, contributing to preserving their body condition. Depending on density, which was particularly impacted by harsh environmental conditions, niche overlap fluctuated across years, leading to niche enlargement of densely populated species, except for catfish. These mechanisms enabled species coexistence, allowing the co-occurrence of alien and native predators within the same ecosystem. This work advocates for time-integrated studies of trophic webs because they capture the variability of their dynamics better than a static picture. This is particularly true for juveniles whose survival strongly depends on their capacity to cope with competition. Information from trophic mid-term studies of juveniles provides valuable guidance for optimised management of species.

Актуальность исследования заключается в получении актуальных изотопно-геохимических данных о природных водах и вмещающих горных породах проявления радоновых вод Седова Заимка. Цель: изучить особенности химического состава природных вод и водовмещающих пород и получить первые сведения по активности 222Rn и изотопному составу δD, δ18O, δ13С, 234U, 238U, 226Ra и 228Ra. Методы. Лабораторное изучение химического состава методами титриметрии, ионной хроматографии, масс-спектрометрии с индуктивно связанной плазмой проводилось в ПНИЛ гидрогеохимии ИШПР ТПУ. Определение комплекса величин δD, δ18O, δ13СDIC вод и растворенного неорганического углерода (Dissolved Inorganic Carbon (DIC)) проводилось в центре коллективного пользования ИГМ СО РАН с помощью прибора Isotope Ratio Mass Spectrometer FinniganTM MAT 253, снабженного приставками пробоподготовки H/Device (для определений δD) и GasBench II (для определений δ18O и δ13СDIC). Измерение содержаний 222Rn в водах проводилось на комплексе «Альфарад плюс» в лаборатории гидрогеологии осадочных бассейнов Сибири ИНГГ СО РАН. Данные по общей β-активности вод, а также активностях 234U, 238U, 226Ra и 228Ra получены после предварительной радиохимической пробоподготовки на альфа-спектрометре ALPHA-ENSEMBLE-8 (Ametek, ORTEC, США); гамма-спектрометрической системе, скомпонованной на базе колодезного коаксиального HPGe ППД с низкофоновым криостатом EGPC 192-P21/SHF 00-30A-CLF-FA фирмы EURISYS MEASURES (Франция) и альфа-бета радиометре для измерения малых активностей УМФ-2000 с кремниевым детектором (НПО «Доза», Россия). Разделение данных на однородные геохимические совокупности выполнено с помощью коэффициентов Са/Na, Са/Mg, Ca/Si, Mg/Si, Na/Si. Для выявления степени концентрирования химических элементов в природных водах были рассчитаны коэффициенты концентрации Kki = mx nx и водной миграции (по А. И. Перельману) Kx1= mx∙100 a∙nx. Результаты. Открыто проявление радоновых вод Седова Заимка, и впервые выполнены комплексные изотопно-геохимические исследования. Радоновые воды (активность 222Rn до 428 Бк/дм3) в основном характеризуются HCO3 Mg-Na-Ca составом с величиной общей минерализации от 158 до 581 мг/дм3 и содержанием кремния от 4,34 до 30,84 мг/дм3. Геохимические параметры среды варьируют от восстановительной до окислительной обстановки с величинами Eh от -40,2 до +28,4 мВ; pH от 7,5 до 7,6 и O2раств. от 2,99 до 5,24 мг/дм3. Значения геохимических коэффициентов составляют: Ca/Na 77,17; Ca/Mg 6,63; Ca/Si 11,42; Mg/Si 1,48; Na/Si 0,92; Si/Na 15,34; rNa/rCl 2,12; SO4/Cl 4,02, что закономерно указывает на процессы формирования химического состава радоновых вод во вмещающих породах преимущественно алюмосиликатного состава. Среди микрокомпонентов наиболее высокими средними содержаниями выделяются (мг/дм3): Si=17,77; Fe=1,18; Mn=0,16; Zn=0,020 и W=0,0036. Значимых коэффициентов концентрации микрокомпонентов не выявлено. Сильной миграционной способностью в растворе обладает Sr, средней - Si, Mn, Ba, Cs и U. Суммарная β-активность вод составляет 32 мБк/дм3. Содержания природных радионуклидов варьируют (мг/дм3): 238U от 3,91∙10-4 до 6,39∙10-4; 232Th от 6,02∙10-6 до 2,37∙10-5 и 226Ra от 6,66∙10-11 до 1,09∙10-10. 232Th/238U отношение в водах изменяется от 1,02∙10-2 до 3,71∙10-2, что является следствием окислительной геохимической обстановки, в которой торий не мигрирует. Уранизотопное отношение (γ) 234U/238U составляет 5,75 при активности изотопов урана (мБк/дм3): 234U (115±7), 238U (20±2), что указывает на неглубокую циркуляцию изученных вод. Активность изотопов радия в водах равна у 226Ra 70±7, а у 228Ra 51,8±3,9 мБк/дм3. Отношение 226Ra/228Ra в HCO3 Mg-Na-Ca радоновых водах составляет 1,35. Изотопный состав радоновых вод (от -126,3 до -121,1 ‰ для δD и от -16,8 до -16,3 ‰ для δ18O) указывает на их метеорно-инфильтрационное происхождение. Изотопный состав углерода δ13CDIC указывает на биогенное происхождение углекислоты и ее участие в процессе карбонат-силикатного выветривания пород. Relevance of the investigation is in obtaining actual isotope-geochemical data on natural waters and water-bearing rocks in the Sedova Zaimka, an occurrence of radon waters. Objective: to study the features of chemical composition of natural waters and water-bearing rocks, and to obtain the first data on the activity of 222Rn and on the isotope composition: δD, δ18O, δ13С, 234U, 238U, 226Ra and 228Ra. Methods. Laboratory studies of the chemical composition by means of titration, ion chromatography, mass spectrometry with inductively coupled plasma were carried out at the Research Laboratory of Hydrogeochemistry at the School of Earth Sciences and Engineering of the Tomsk Polytechnic University. Determination of the set of parameters δD, δ18O, δ13СDIC in waters and dissolved inorganic carbon was carried out at the Shared Equipment Center if the IGM SB RAS with the help of Isotope Ratio Mass Spectrometer FinniganTM MAT 253, equipped with sample preparation attachments H/Device (to determine δD) and GasBench II (to determine δ18O and δ13СDIC). 222Rn concentration in waters was determined using the Alfarad Plyus instrument in the Laboratory of Hydrogeology of Sedimentary Basins of Siberia at the IPGG SB RAS. The data on the total β-activity of waters, as well as on the activities of 234U, 238U, 226Ra and 228Ra, were obtained after preliminary radiochemical sample preparation using an alpha spectrometer ALPHA-ENSEMBLE-8 (Ametek, ORTEC, USA); gammaspectrometric system arranged on the basis of well coaxial HPGe semiconductor detector with low-background cryostat EGPC 192- P21/SHF 00-30A-CLF-FA (EURISYS MEASURES, France) and alpha-beta radiometer UMF-2000 with a silicon detector (Doza, Russia) to measure low activities. Data separation into homogeneous geochemical sets was performed with the help of Са/Na, Са/Mg, Ca/Si, Mg/Si, Na/Si coefficients. To determine the extent of element concentrating in natural waters, the coefficients of concentration Kki=mx nx and water migration (according to A. I. Perelman) Kx1= mx∙100 a∙nx were calculated. Results. Radon water occurrence at Sedova Zaimka was discovered, and isotope-geochemical investigation was carried out. Radon waters (with 222Rn activity up to 428 Bq/dm3) are mainly characterized by HCO3 Mg-Na-Ca composition with TDS 158 to 581 mg/dm3 and silicon content 4,34 to 30,84 mg/dm3. The geochemical parameters of the environment vary from reductive to oxidative settings with Eh from -40,2 to +28,4 mV; pH from 7,5 to 7,6 and O2dissolved from 2,99 to 5,24 mg/dm3. Geochemical coefficients are equal to: Ca/Na 77,17; Ca/Mg 6,63; Ca/Si 11,42; Mg/Si 1,48; Na/Si 0,92; Si/Na 15,34; rNa/rCl 2,12; SO4/Cl 4,02, which is a regular indication of the formation of radon water composition in the embedding rocks of mainly aluminosilicate composition. Among trace components, the highest average content is characteristic of (mg/dm3): Si=17,77; Fe=1,18; Mn=0,16; Zn=0,020 and W=0,0036. No significant coefficients of component concentrations were revealed. Strong migration ability in solution is exhibited by Sr, medium - by Si, Mn, Ba, Cs and U. The total β-activity of the waters is 32 mBq/dm3. The concentrations of natural radionuclides vary (mg/dm3): 238U from 3,91∙10-4 to 6,39∙10-4; 232Th from 6,02∙10-6 to 2,37∙10-5 and 226Ra from 6,66∙10-11 to 1,09∙10-10. The 232Th/238U ratio in the waters varies from 1,02∙10-2 to 3,71∙10-2, which is a consequence of the oxidative geochemical setting, in which thorium does not migrate. The uranium isotope ratio (γ) 234U/238U is 5,75, with the activity of uranium isotopes (mBq/dm3): 234U (115±7), 238U (20±2), which points to not very deep circulation of the studied waters. The activity of radium isotopes in the waters is 70±7 mBq/dm3 for 226Ra and 51,8±3,9 mBq/dm3 for 228Ra. The 226Ra/228Ra ratio in HCO3 Mg-Na-Ca radon waters is equal to 1,35. The isotope composition of radon waters (from -126,3 to -121,1 ‰ for δD and from -16,8 to -16,3 ‰ for δ18O) points to their meteoric infiltration origin. The isotope composition of carbon δ13CDIC points to the biogenic origin of carbon dioxide and its participation in carbonate-silicate weathering of the rocks.

Stable hydrogen, carbon, nitrogen, oxygen and sulfur (HCNOS) isotope compositions expressed as isotope-delta values are typically reported relative to international standards such as Vienna Standard Mean Ocean Water (VSMOW), Vienna Peedee belemnite (VPDB) or Vienna Cañon Diablo Troilite (VCDT). These international standards are chosen by convention and the calibration methods used to realise them in practice undergo occasional changes. To ensure longevity and reusability of published data, a comprehensive description of (1) analytical procedure, (2) traceability, (3) data processing, and (4) uncertainty evaluation is required. Following earlier International Union of Pure and Applied Chemistry documents on terminology and notations, this paper proposes minimum requirements for publishing HCNOS stable-isotope delta results. Each of the requirements are presented with illustrative examples.

Man has profoundly modified the upper valley of the Uruguay River and its basin. The plains of these valleys and the lower areas of the hills have been modified for agricultural production, leaving small patches of wild forest on the tops of the hills, where wildlife takes refuge. These less modified sectors generally lack water. Therefore, the wild mammals must descend to the bottom of the valleys to drink. However, there are numerous fence lines between the hills and the rivers and streams which prevent the fauna access to these watercourses, so they ingest water from artificial ponds present in the agricultural establishments instead, which is reflected in the high values of δ18O observed in the bone bioapatite of local wild mammals. This finding highlights the importance of artificial reservoirs distributed in the agricultural landscape of Santa Catarina for the preservation of wildlife and the importance of their sanitary monitoring to prevent the transmission of diseases from livestock to wildlife. Resumo O homem tem modificado profundamente a região abrangida pela bacia do alto rio Uruguai. As planícies deste rio e as partes baixas dos morros têm sido modificadas para a produção agrícola, deixando pequenas parcelas de mata natural, principalmente nas partes altas dos morros, onde se refugia a vida silvestre. Estes setores menos modificados, geralmente, carecem de água, fazendo com que a fauna se desloque até o fundo dos vales para beber. Contudo, existem diferentes obstáculos entre os morros e os rios e córregos, que impedem o acesso diário da fauna aos cursos d’ água, por isso acabam bebendo dos reservatórios artificiais presentes nos estabelecimentos agrícolas, o que se expressa nos altos valores de δ18O observados na bioapatita óssea dos mamíferos selvagens locais. Estes dados destacam a importância dos reservatórios artificiais distribuídos na paisagem agrícola de Santa Catarina, para a preservação da vida silvestre, bem como a importância que tem a vigilância sanitária para prevenir a transmissão de enfermidades dos animais domesticados na vida silvestre.

Although marine resources are known to have been exploited by both foragers and early farmers in Scotland, the importance of seafood to the diets of Neolithic groups has been widely debated. Here we present paired stable isotope (δ13C and δ15N) and radiocarbon measurements on Early Neolithic human remains from Raschoille Cave in Oban. These are compared with published data for other sites in western Scotland and used to re-evaluate the use of marine resources by the first farmers. The diets of Late Mesolithic foragers and Early Neolithic farmers were modelled from stable isotope data using both Linear and Bayesian (FRUITS) mixing models. Our FRUITS dietary models indicate that Mesolithic foragers obtained much of their dietary protein and calories from marine resources, consistent with the predominance of shellfish, fish and sea mammal remains in their shell middens. Of note is the large proportion of dietary calories obtained from plant foods, which is like that of the early farming groups. The diets of Early Neolithic farmers appear relatively homogeneous across Scotland. Plant foods were the primary source of calories. Meat and/or dairy from terrestrial mammals were the most important source of dietary protein. Marine resources were, at most, a minor component of the ‘lifetime’ diet.

Lipid-biomarkers have been used to reconstruct environmental changes in lacustrine systems on a range of time scales. Lake sediments are excellent archives to apply these tools due to their rapid and amplified response to environmental pressures. For the past thirty years, the hypersaline lagoons of the Rio de Janeiro coastal plain have been studied as natural laboratories for the observation of the biogeochemical processes involved in modern dolomite precipitation. Here, we apply a multiproxy approach to characterize two depositional stages during the Holocene that may have triggered primary dolomite formation in these lagoonal environments. A first stage, with two sub-stages (1A − 6.1 to 4.2 kyr. BP; 1B − 4.2 to ∼3.6 kyr. BP) was deposited during the sea-level rise, with sediments containing an abundance of long-chain n-alkanes with 2H-depleted (δ2Hn-alk) signatures indicating riverine inputs of terrestrial organic carbon during prevailing wet conditions. A second stage (, Geochimica et Cosmochimica Acta, 337, ISSN:0016-7037, ISSN:1872-9533

Background Edible insects are a novel source of animal protein. Moreover, edible insects contain iron concentrations similar to meat, potentially making them a valuable iron source for human consumers. Yet, it is unknown to what extent iron from insects is absorbed in humans. Objectives In this exploratory study, we assessed fractional iron absorption from house crickets (Acheta domesticus) consumed with refined (low-phytate, noninhibiting) or nonrefined (high-phytate, inhibiting) meals. Methods Intrinsically [57Fe]-labeled and control crickets were reared. Six iron-balanced experimental meals were randomly administered crossover to 20 iron-depleted females (serum ferritin, The American Journal of Clinical Nutrition, ISSN:0002-9165, ISSN:1938-3207

This is the data repository for the manuscript ""A Carbon Source in a Carbon Sink: Carbon Dioxide and Methane Dynamics in Boreal Peatland Open-Water Pools" submitted to Global Biogeochemical Cycles on 07 July 2023.

Information on habitat use among highly migratory green sea turtles is especially important for effective conservation – especially in urban habitats. However, long migration distances between sea turtle feeding grounds and nesting beaches make these long-lived marine reptiles difficult to study. Combining techniques, such as skeletochronology with stable isotope values from annual bone growth layers, can help determine life history traits and movement patterns of sea turtles. For one component of my capstone project, I helped members of the Marine Turtle Ecology and Assessment Program at the NOAA Southwest Fisheries Science Center take inventory of the East Pacific (EP) population of green turtles in San Diego Bay. Along with fieldwork, I worked in NOAA’s Marine Turtle Demography Laboratory prepping samples for stable isotope analysis. Finally, I analyzed data collected by NOAA to evaluate if trace elements found in bones, such as barium (Ba), magnesium (Mg), and strontium (Sr), could also be used toreconstruct transitions between oceanic and coastal life stages in sea turtles. For my capstone deliverable, I combined geographic maps, satellite telemetry data, stable isotope data, skeletochronology data, narrative text, and multimedia content to share case studies of well-known EP green sea turtles in an interactive, dynamic, and meaningful way. The long-term data stored in the bones of sea turtles, along with the information gained from multiple captures over time, has helped reconstruct movement patterns of these highly migratory reptiles. Through my ArcGIS Storymap, I can share this conservation success story - to give people hope, to inspire action, and to ensure the protection and continued success of these turtles and their habitat. I hope the turtle stories bring curiosity, and a better understanding of the amazing science that is improving conservation efforts for sea turtles around the globe.

Stable isotope tracers, like

International audience; The present study, conducted in the Galion Bay in Martinique, aims to highlight the temporal and seasonal variations of chlordecone contamination (an organochlorine pollutant) in the ambient environment (seawater) but also in the marine organisms in three main coastal marine habitats (mangroves, seagrass beds and coral reefs). To this end, two methodologies were used to measure and compare the chemical contamination of seawater during 13 months (spot samplings and POCIS technique). In parallel, concentrations of chlordecone and isotopic ratios (C and N) were carried out on marine organisms, collected during two contrasting climatic periods (dry and rainy), to evidence seasonal variations. The results showed that the contamination of seawater displayed significant variations over time and depended on environmental factors such as water flows, which imply dilution and dispersion phenomena. Concerning the marine organisms, the level of contamination varied considerably between the two seasons in seagrass beds with higher levels of contamination during the rainy season. Reef organisms were more moderately affected by this pollution, while mangrove organisms Environnemental Science and Pollution Research 2022 2 showed a high level of chlordecone whatever the season. Finally, isotope analyses highlighted that bioamplification along marine food-webs occurs at each season and each station.

The Antarctic ice sheet’s future contribution to sea level rise is difficult to predict, mostly because of the uncertainty and variability of the surface mass balance (SMB). Ice cores are used to locally (km scale) reconstruct SMB with a very good temporal resolution (up to sub-annual), especially in coastal areas where accumulation rates are high. The number of ice cores records has been increasing these last years, revealing an important spatial variability and different trends of SMB, highlighting the crucial need for greater spatial and temporal representativeness. We present records of density, water stable isotopes (δ18O, δD and deuterium excess), ions concentrations (Na+, K+, Mg+, Ca+, MSA, Cl-, SO42- and NO3-), and continuous electrical conductivity measurement (ECM), as well as age models and resulting surface mass balance from the top 120 m of two ice cores (FK17 and TIR18) drilled on two adjacent ice rises located in coastal Dronning Maud Land and dating back to the end of the 18th century. Both environmental proxies and derived data show contrasting behaviors, suggesting strong spatial and temporal variability at the regional scale. In terms of precipitation proxies, both ice cores show a long-term decrease of deuterium excess (d-excess) and a long-term increase of δ18O, although less pronounced. In terms of chemical proxies, the non-sea-salt sulfate (nssSO42-) concentrations of FK17 are twice the ones of TIR18 and display an increasing trend on the long-term while there is only a small increase after 1950 in TIR18. The SO42- / Na+ ratios show a similar contrast between FK17 and TIR18 and are consistently higher than the sea water ratio, indicating a dominant impact of the nssSO42- on the SO42- signature. The mean long-term SMB is similar for FK17 and TIR18 (0.57 and 0.56 m i.e. a-1 respectively), but the annual records are very different: since the 1950’s, TIR18 shows a continuous decrease while FK17 has shown an increasing trend until 1995 followed by a recent decrease. The datasets presented here offer numerous development possibilities for the interpretation of the different paleo profiles and for addressing the mechanisms behind the spatial and temporal variability observed at the regional scale (tens of km scale) in East Antarctica. The “Mass2Ant IceCores” datasets are available on Zenodo (https://doi.org/10.5281/zenodo.7848435; Wauthy et al., 2023).

This research aims to attain the optimal method of removing the high salinity concentrations without its effect on the balance or accuracy of stable isotopes measurement of deuterium and oxygen-18 (δ18O, δ2H). Four treatment methods (i.e., distillation, vacuum distillation, electro dialysis and ion exchange) were applied for nine samples, which were obtained from different water sources (sea, groundwater, river).l Worth to notice that the samples have Electrical Conductivity (EC) ranged (1000–60,000 µs/cm). Liquid–Water Isotope Analyzer used to measure the isotope concentration of δ18O, δ2H. The research findings of the four applied methods revealed their effectiveness with various percentages (normal distillation: 92.37%; vacuum distillation: 88.31%; electro dialysis: 94.85%; ion exchange: 99.62%). In addition, the investigation was conducted a clear correspondence measurement of (δ18O, δ2H) isotopes before and after treatment. The four methods results indicated that samples with EC ranged (1000–5000 µs/cm) have no effect on stable isotope readings. Whereas, samples with EC higher than 10,000, have substantial influence on the stable isotope readings. Finally, vacuum distillation method attained the best results among the treatment methods for EC ranged (10,000–60,000 µs/cm) without affecting the isotopic content of (δ18O, δ2H). There is a clear correspondence of the stable isotopic measurements before and after treatment, for all the selected samples.

Funder: Ludwig-Maximilians-Universität München (1024), Stable carbon and nitrogen isotopic ratios (δ13C, δ15N) in bone collagen of archaeological skeletal finds are indicators of the protein sources in individuals’ basic diet. Isotopic sourcing allows us to quantify the biomass contribution of major dietary components and to differentiate between the source contribution of various animal species (domesticates, game). We re-evaluated previously published isotopic signatures in skeletons from three burial sites in Bavaria, dated from Late Antiquity to Early Mediaeval times (Erding-Klettham, Erding-Altenerding, Straubing-Bajuwarenstraße) by use of a mixing model. The result is a more detailed reconstruction, supported by contextual evidence, of both early subsistence economies and individual dietary preferences. We were able to confirm relationships between non-local dietary behaviour and foreign cultural influences (grave goods and artificial cranial modification) that have previously been suggested by the burial context and DNA analyses and that are plausibly explained by migration events. Moreover, we differentiated early and late immigrants from each other, requiring a re-evaluation of the earlier interpretation of exogamy. In addition, individual dietary preferences indicate even more migration events and social stratifications that could not previously be identified by the archaeological evidence alone.

Ectomycorrhizal (ECM) fungi are key players in forest carbon (C) sequestration, receiving a substantial proportion of photosynthetic C from their forest tree hosts in exchange for plant growth-limiting soil nutrients. However, it remains unknown whether the fungus or plant controls the quantum of C in this exchange, nor what mechanisms are involved. Here, we aimed to identify physiological and genetic properties of both partners that influence ECM C transfer. Using a microcosm system, stable isotope tracing, and transcriptomics, we quantified plant-to-fungus C transfer between the host plant Eucalyptus grandis and nine isolates of the ECM fungus Pisolithus microcarpus that range in their mycorrhization potential and investigated fungal growth characteristics and plant and fungal genes that correlated with C acquisition. We found that C acquisition by P. microcarpus correlated positively with both fungal biomass production and the expression of a subset of fungal C metabolism genes. In the plant, C transfer was not positively correlated to the number of colonized root tips, but rather to the expression of defence- and stress-related genes. These findings suggest that C acquisition by ECM fungi involves individual fungal demand for C and defence responses of the host against C drain.

Caves containing perennial ice deposits make up a little-known, but emerging part of the cryosphere under increasing scrutiny from the scientific community. M-17, a sag-type ice cave opening at 1879 m asl in the Tolminski Migovec massif of the Julian Alps (NW Slovenia) contains a perennial underground ice deposit whose paleoclimate sensitivity is poorly understood and whose longevity under current climate change is at risk. The past mass balance of this cave is constrained using wood macro-remains embedded in ice. Accelerator mass spectrometry radiocarbon dating of 18 wood samples embedded in ice provides the largest currently available dataset for a subterranean ice deposit in the southern European Alps. The reconstructed chronostratigraphy reveals three main phases of likely positive ice balance around 900–1100 AD, 1200–1300 AD, and 1700–1800 AD, as well as a period of negative mass balance around 1300–1400 AD. The onset of cave glaciation is deemed to have occurred no later than about 900 AD, with evidence of overall positive ice mass balance during multi-decadal periods characterized by cooler-than-average summers and wetter-than-average springs. Conversely, negative mass balance is recorded during a period warmer-than-average summers and dry springs. The cave has experienced ice mass loss since its discovery in the 1980s.

Predatory fish have occasionally been observed preying on birds, sometimes repeatedly, but few studies were able to unravel the overall significance of avian prey in fish diet and the predation impacts on bird populations. We used a control/impact study setup, using a Nature Reserve in northern Italy and a nearby control area, to determine: 1) the contribution of waterbirds to wels catfish diet in the Reserve, 2) the population density of wels catfish in the Reserve and control area and 3) the potential impacts of waterbird depredation by wels catfish on waterbird population trends. Our stable isotope Bayesian mixing model indicated that birds contributed 12.2% (5–27.9%, 50% confidence interval) of the diet of large wels catfish (> 98 cm in total length). Large individuals constituted the majority of the population in the shoreline areas of the reserve in 2013–2019, where the population was stable despite control efforts. Numbers were below detectable levels in the control area. Large wels catfish consumed an average of 224, 148 and 187 kg of birds during the 2019 chick growing period, as estimated through three different bioenergetic models. Compared to the control area, mallard reproductive success was diminished in the Reserve, likely due to higher rates of fish predation, although effects were variable in different years. Overall, our data suggest that high densities of invasive wels catfish might impact waterbird reproductive success through predation on bird chicks, but further studies would be needed to reduce uncertainties related to the intrinsic variability of field ecology data. Our study constitutes a preliminary attempt to assess the potential of introduced wels catfish to affect the conservation value of waterbird protection areas, and should be repeated at broader spatial and temporal scales.

his study presents oxygen (δ18O) and carbon (δ13C) stable isotope records of two U-Th dated stalagmites from Mljet Island caves in the southern part of Croatian Adriatic. Speleothem MSM-1 from Mala špilja Cave recorded environmental changes during Marine Isotope Stage (MIS) 5 (119- 101 ka and 91–81 ka BP), MIS 4 (60–54 ka BP), MIS 3 (43–35 ka BP). Short interval (18–13.5 ka BP) during the Last Glacial Maximum (MIS 2) is recorded in stalagmite VSM-1 from Velika špilja Cave. δ18O and δ13C profiles display main climatic oscillations correlated within the age uncertainty with stadial–interstadial events recorded in North Greenland ice core (NGRIP) such as Dansgaard- Oeschger (DO) (25, 24, 17, 16, 15, 11, 10, 9, 8 and 7) and Heinrich event (HE) 1 revealing their impact on the paleoenvironmental conditions in the region of Croatian Eastern Adriatic. Deposition hiatuses occurred during periods of very low δ18O recorded in NGRIP ice core, indicating the adverse effect of cold (dry) conditions on speleothem deposition.

The present study aims to investigate the origin, type, thermal maturity and hydrocarbon generation potential of organic matter and paleo-depositional environment of the Early Paleocene (Danian) Hangu Formation outcropped in the Kala-Chitta Range of Northwest Pakistan, Eastern Tethys. Organic-rich shale and coal intervals were utilized for geochemical analyses including TOC (total organic carbon) and Rock–Eval pyrolysis coupled with carbon (δ13Corg) and nitrogen (δ15Norg) stable isotopes. The organic geochemical results showed that the kerogen Type II (oil/gas prone) and Type III (gas prone) dominate the investigated rock units. The TOC (wt%) and S2 yield indicate that the rock unit quantifies sufficient organic matter (OM) to act as potential source rock. However, the thermal maturity Tmax°C marks the over maturation of the OM, which may be possibly linked with the effect attained from nearby tectonically active Himalayan Foreland Fold-and-Thrust Belt system and associated metamorphosed sequences. The organic geochemical analyses deciphered indigenous nature of the OM and resultant hydrocarbons. The δ13Corg and δ15Norg stable isotopic signatures illustrated enrichment of the OM from both marine and terrestrial sources accumulated into the Hangu Formation. The Paleo-depositional model established using organic geochemical and stable isotopic data for the formation supports its deposition in a shallow marine proximal inner shelf environment with prevalence of sub-oxic to anoxic conditions, a scenario that could enhance the OM preservation. Overall, the formation holds promising coal and shale intervals in terms of organic richness, but due to relatively over thermal maturation, it cannot act as an effective source rock for liquid hydrocarbon generation and only minor amount of dry gas can be expected. In implication, the results of this study suggest least prospects of liquid hydrocarbon generation potential within Hangu Formation at studied sections.

Lithium is an economically important element that is increasingly extracted from brines accumulated in continental basins. While a number of studies have identified silicic magmatic rocks as the ultimate source of dissolved brine lithium, the processes by which Li is mobilized remain poorly constrained. Here we focus on the potential of low-temperature, post-eruptive processes to remove Li from volcanic glass and generate Li-rich fluids. The rhyolitic glasses in this study (from the Yellowstone-Snake River Plain volcanic province in western North America) have interacted with meteoric water emplacement as revealed by textures and a variety of geochemical and isotopic signatures. Indices of glass hydration correlate with Li concentrations, suggesting Li is lost to the water during the water-rock interaction. We estimate the original Li content upon deposition and the magnitude of Li depletion both by direct in situ glass measurements and by applying a partition-coefficient approach to plagioclase Li contents. Across our whole sample set (19 eruptive units spanning ca. 10 m.y.), Li losses average 8.9 ppm, with a maximum loss of 37.5 ppm. This allows estimation of the dense rock equivalent of silicic volcanic lithologies required to potentially source a brine deposit. Our data indicate that surficial processes occurring post-eruption may provide sufficient Li to form economic deposits. We found no relationship between deposit age and Li loss, i.e., hydration does not appear to be an ongoing process. Rather, it occurs primarily while the deposit is cooling shortly after eruption, with δ18O and δD in our case study suggesting a temperature window of 40° to 70°C.

Changes in body size and composition, i.e., body weight (BW) gain or loss, affect the daily energy expenditure (EE). To ensure an appropriate BW reduction and to find an efficient strategy to reduce and maintain a target BW, regular evaluations and adjustments of energy allowance are important. This study aimed to provide a detailed knowledge about the possible changes in resting EE using the oral 13C-bicarbonate technique (o13CBT) as a research tool in 16 overweight pet dogs undergoing BW reduction. Dietary composition (i.e., in % of dry matter [DM] being a high protein [33.3], low fat [9.6], and high crude fiber [18.0] diet [LFHFibre], and a high protein [37.9], high fat [52.0], carbohydrate-free diet [HFat]) during 16 wk of energy restriction were evaluated regarding effects on resting EE, rate of BW reduction, body composition, and plasma concentrations of metabolic hormones involved in energy metabolism and appetite regulation. The mean BW loss was higher (P 0.05). Resting EE was lower (P 0.05) consisted of both fat mass (FM) and fat-free mass (FFM). Energy expenditure, calculated in relation to amount of FFM, was not significantly (P > 0.05) affected by BW reduction. Dietary composition did not significantly affect (P > 0.05) plasma concentrations of insulin, leptin, and ghrelin, and no effect (P > 0.05) of BW reduction was observed on hormone concentrations. In conclusion, the o13CBT proved to be a useful research method for studying short-term EE in overweight dogs. Even though all dogs lost BW, most dogs were still overweight at the end of the study. Due to a high individual variation among dogs, a longer experimental period with a larger sample size would be desirable.

Patagonia is ideally situated to reconstruct past migrations of the southern westerly winds (SWWs) due to its southerly maritime location. The SWWs are an important driver of Southern Ocean upwelling and their strength and latitudinal position changed during the Holocene, leading thus to different responses of the vegetation to past climate changes along the Chilean continental margin. A new speleothem record from Cueva Chica (51°S) is investigated to reconstruct past climatic changes throughout the Holocene in conjunction with other marine and paleoenvironmental records of the region and better constrain the regional paleoclimatic evolutions of SWWs. Samples comprising both a flowstone core and a stalagmite were radiometrically dated (Usingle bondTh & 14C) to construct age-depth models for the highly-resolved proxy profiles (δ13C, δ18O, chemical composition). The Cueva Chica record provides a highly-resolved isotopic and elemental curves for the last 12 ka, albeit with a hiatus from 5.8 to 4 ka BP. The multi-proxy analysis suggests three climatic regimes throughout the Holocene in Southern Patagonia: i) an early Holocene wet period (with the exception of two dry excursions at 10.5 ka and 8.5 ka BP), ii) a mid-Holocene dry period and iii), a return to generally wet conditions over the late Holocene. The global drivers for these tri-phased climatic regimes are likely related to oceanic and South polar feedbacks. The early Holocene was the warmest period and might be attributable to changes in global ocean circulation which involved a rise in air T° and a strength in SWW from 50°S, and therefore higher precipitations over landmass. After 9 ka BP, an intensified deglaciation dynamic along the Antarctic Peninsula is concordant with increasing summer insolation in the Southern hemisphere, leading to a poleward shift of the SWWs in response to global warming and thus to a reduction in moisture supply from the Pacific onto the Patagonian shore. After 5 ka BP, a gradual SST decline is consistent with an equatorward shift of the SWWs in response to a cooling Southern hemisphere. The SWW storm tracks extended to lower latitudes, inducing a return to wetter conditions with highly variable moisture patterns along the Patagonian landmass. Clumped isotope (Δ 47) analyses at lower resolution reflect the degree of kinetic isotope fractionation at the time of carbonate deposition, especially during the dry interval around 8.5–5.5 ka BP. Reduced kinetic isotope fractionation is observed since at least 2.6 ka BP, a period marked by (slightly) wetter conditions.

A petrographic and geochemical investigation of a Neoarchean sedimentary section from the Pilbara region of Western Australia

Early detection of volcanic eruptions is of major importance for protecting human life. Ground deformation and changes in seismicity, geochemistry, petrology, and gravimetry are used to assess volcanic activity before eruptions. Studies on Mt. Etna (Italy) have demonstrated that vegetation can be affected by pre-eruptive activity before the onset of eruptions. During two consecutive years before Mt. Etna's 2002/2003 flank eruption, enhanced vegetation index (NDVI) values were detected along a distinct line which later developed into an eruptive fissure. However, the mechanisms by which volcanic activity can lead to changes in pre-eruption tree growth processes are still not well understood. We analysed delta C-13, delta O-18 and C-14 in the rings of the survived trees growing near to the line where the pre-eruptive increase in NDVI was observed in order to evaluate whether the uptake of water vapour or fossil volcanic CO2 could have contributed to the enhanced NDVI. We found a dramatic decrease in delta O-18 in tree rings formed before 2002/2003 in trees close to the eruption fissure, suggesting uptake of volcanic water by trees during pre-eruptive magma degassing. Moist conditions caused by outgassing of ascending magma may also have led to an observed reduction in tree-ring delta C-13 following the eruption. Furthermore, only ambiguous evidence for tree uptake of degassed CO2 was found. Our results suggest that additional soil water condensed from degassed water vapour may have promoted photosynthesis, explaining local increases in NDVI before the 2002/2003 Mt. Etna flank eruption. Tree-ring oxygen stable isotopes might be used as indicators of past volcanic eruptions., Ecohydrology, 14 (8), ISSN:1936-0592, ISSN:1936-0584

For decades, theory has upheld that plants do not fractionate water isotopes as they move across the soil-root interface or along plant stems. This theory is now being challenged by several recent studies reporting that the water held in woody stems has an isotopic composition that cannot be attributed to any potential water source. Isotopic offsets between stem and source water still need to be explained, as they prevent identifying unambiguously tree water’s origin from water isotope measurements. Here we show that isotopic offsets between stem and source water can be explained by micrometer-scale water isotope heterogeneity within woody stems and soil micropores. Using a novel technique to extract sap water in xylem conduits separately from the water held in other xylem tissues, we show that these non-conductive xylem tissues are more depleted in deuterium than sap water. We also report that, in cut stems and well-watered potted plants, the isotopic composition of sap water reflects well that of irrigation water, demonstrating that no isotopic fractionation occurs during root water uptake or the sap water extraction process. Previous studies showed that isotopic heterogeneity also exists in soils at the pore scale where water adsorbed onto soil particles is more depleted than capillary/mobile soil water. Data collected at a beech (Fagus sylvatica) forest indicate that sap water matches best the capillary/mobile soil water from deep soil horizons, indicating that micrometer-scale water isotope heterogeneity in soils and stems must be accounted for to unambiguously identify where trees obtain their water within catchments.Significance StatementForests are prime regulators of the water cycle over land. They return, via transpiration, a large fraction of precipitation back to the atmosphere, influence surface runoff, groundwater recharge or stream flow, and enhance the recycling of atmospheric moisture inland from the ocean. The isotopic composition of water in woody stems can provide unique information on the role forests play in the water cycle only if it can be unambiguously related to the isotopic composition of source water. Here, we report a previously overlooked isotopic fractionation of stem water whereby non-conductive tissues are more depleted in deuterium than sap water, and propose a new technique to extract sap water separately from bulk stem water to unambiguously identify plant water sources.

Current paleodietary studies about the Naviform and Talayotic groups that took place in Minorca (Balearic Islands) during the Late Bronze Age–Early Iron Age (ca.1600–850/800 BC) have suggested a mixed and variable diet, largely depending on terrestrial sources of vegetables and meat. This study explores the nutritional pattern of the individuals buried in the Cova des Pas site (Minorca Island, Spain), a cave used as a collective sepulcher and the most exceptional and major human assemblage found in the Balearic Islands during this period. Carbon (δ13C) and nitrogen (δ15N) stable isotopic signatures were measured on extracted bone collagen from 49 individuals. Further, faunal remains from the Son Mercer de Baix site, the closest contemporaneous village to the collective sepulcher, were also analyzed to provide a baseline corpus of data to interpret human isotopic data. The results indicate a human diet based mainly on C3 plants with an important consumption of animal protein. The δ15N values of infants up to 4 years were high, indicating the enriched isotopic signature of breast milk, and weaning is assumed to occur around this age. Differences between sexes and the age subcategories were not statistically significant, assuming that the different groups of society had the same access to food. The data obtained in this isotopic study provides insight into the palaeodietary pattern of the human groups dated to the Late Bronze Age–Early Iron Age ages in the island of Minorca, contributing to the present debate on the emergence and development of complex societies on the Balearic archipelago., This research was supported by the Spanish Ministry of Science and Innovation through the “María de Maeztu” excellence accreditation (CEX2019-000945-M). CT was supported by the Spanish Ministry of Science and Innovation through the “Ramon y Cajal” program (RYC2020-029404-I). AM and XJ are members of the GREAB supported by Generalitat de Catalunya (Ref. 2017 SGR 1630). PS was supported by the Xunta de Galicia-GAIN (IN606C-2021/002) and the Spanish Ministry of Science and Innovation through the “Juan de la Cierva-Incorporación” programme (IJC2020-042714-I/ AEI/https://doi.org/10.13039/501100011033)., With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2019-000945-M).

The bioarchaeological material collected in Lithuania has been studied fragmentary until now and but it gave the possibility to better understand the past inhabitants’ lifestyles and their relationship with the environment, as well as to assess the distribution of food resources in past populations. The aim of the dissertation is to carry out a systematic analysis of carbon and nitrogen stable isotope ratios of human and animal bioarchaeological material and to evaluate their variation in the aspects of palaeodiet and palaeoecology in various historical periods, including the Iron Age – Modern times. The stable isotope ratio method helped to understand how different dietary resources were distributed in the population, to compare individuals, and to relate the differences to the individual's age, status, region, and period of living, to assess the humans’ influence on the domestic animals’ diet. It was found that the basis of the human and animal diet consisted of C3 photosynthetic plants. In the early period (from the 2nd to the 13th century), the diet of men and women was differentiated, and the consumption of food of plant origin was higher in general, compared to the late period (from the 13th to the 19th century). As well as appear regional differences between urban, rural, coastal, and the social elites.

The trace elements concentration in the muscle of the Atlanticseabob shrimp (Xiphopenaeus kroyeri) caught in coastal fishinghighlighted copper (Cu) and zinc (Zn), both related to antifoulingsystems, as the main elements related to the intensity of portactivities of southeast Brazil (~20—to 22ºS). The aim of this study isto analyze if the behavior of Cu and Zn in the muscle of this shrimpspecies is constant among different sampling sites, verifying if thespecies is suitable as biomonitor for these elements. The shrimpscame from fisheries done in 2017 in Vitória, Anchieta, and Farolde São Tomé, southeast Brazil. After sampling, each individualwas categorized for gender and maturity stage, measured, andweighted. Bulk muscle samples were freeze-dried for determinationof Cu, Zn, and ratios of stable isotopes of carbon (δ13C) and nitrogen(δ15N). The data analysis verified if the concentration of Cu and Zn inmale and female shrimps vary among maturity stages and samplingsites, and how the concentration of Cu and Zn is related to shrimpsforaging area and/or trophic position. Both bioaccumulation andgrowth dilution occurred, but not in the same way for genders andsampling sites, with Cu showing more variability. Relationshipsbetween elements and shrimps foraging area and trophic positiondid not show a clear trend among the sampling sites. Regressionmodels indicated moderate relationships, explaining 51% (Cu) and60% (Zn) of the association with the foraging area in Anchieta, butup to 8% in Vitória and Farol de São Thomé. For the trophic position,the models explained 33% (Cu) and 34% (Zn) in Anchieta and up to14% in Vitória and Farol de São Thomé. The results showed that theutilization of this shrimp species as biomonitor of marine coastalenvironments near port activities to monitoring the levels of Cu andZn is not a suitable choice, at least in the spatial scale considered bythis study. A concentração de elementos traço no músculo do camarão sete-barbas(Xiphopenaeus kroyeri) capturado na pesca costeira destacou cobre (Cu)e zinco (Zn), ambos relacionados com sistemas anti-incrustantes, como osprincipais elementos associados à intensidade das atividades portuáriasdo Sudeste do Brasil (~20–22ºS). O objetivo deste estudo foi analisarse o comportamento de Cu e Zn no músculo dessa espécie de camarãoera constante entre os diferentes locais de amostragem, verificandose a espécie era adequada como biomonitor para esses elementos.Os camarões vieram de pescarias realizadas em 2017 em Vitória, Anchieta eFarol de São Thomé, Sudeste do Brasil. Após a amostragem, cada indivíduofoi categorizado quanto a sexo e estágio de maturidade, medido e pesado.Amostras compostas de músculo foram liofilizadas para a determinação deCu, Zn e razões de isótopos estáveis de carbono (δ13C) e nitrogênio (δ15N).A análise dos dados verificou se a concentração de Cu e Zn em camarõesmachos e fêmeas variou entre os estágios de maturidade e locais deamostragem, e como a concentração de Cu e Zn estava relacionada à área deforrageamento e/ou posição trófica dos camarões. Tanto a bioacumulaçãoquanto a diluição do crescimento ocorreram, mas não da mesma formapara os gêneros e locais de amostragem, com Cu apresentando maiorvariabilidade. As relações entre os elementos e a área de forrageamentoe a posição trófica dos camarões não mostraram tendência clara entreos locais de amostragem. Modelos de regressão indicaram relaçõesmoderadas, explicando 51% (Cu) e 60% (Zn) da associação com a área deforrageamento em Anchieta, mas somente até 8% em Vitória e Farol deSão Thomé. Para a posição trófica, os modelos explicaram 33% (Cu) e 34%(Zn) em Anchieta e até 14% em Vitória e Farol de São Thomé. Os resultados mostraram que a utilização dessa espécie de camarão como biomonitorde ambientes costeiros marinhos próximos às atividades portuárias paramonitoramento dos níveis de Cu e Zn não é uma escolha adequada, pelomenos na escala espacial considerada neste estudo.

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.

Persistent organic pollutants (POPs) in biota are influenced by ecological, physiological, and physicochemical properties; however, there is a need for a better understanding about the interplay of these parameters on POP dynamics and fate. To address this, POPs in three Lake Erie freshwater fishes (freshwater drum, Aplodinotus grunniens; walleye, Sander vitreus; and white perch, Morone americana) with different feeding ecologies were assessed using life history characteristics and three stable isotopes (δ13 C, δ15 N, and δ34 S). Lipid normalized POP concentrations were in the range of past studies and were generally similar among the three species when all ages were combined. Principal component analysis (PCA) found the two significant PCs (explaining 59% and 10% of the variation), with all POPs loading significantly onto PC1, which indicated a common source of contamination, likely legacy sediment loads. Loadings on both PCs were correlated with POP log KOW . Age, habitat use (δ13 C and δ34 S), trophic position (δ15 N) and interactions between age and δ15 N, age and species, and δ15 N and δ34 S were significant predictors of POP concentration based on PC1 scores, whereas δ13 C and species were significant predictors of PC2 scores. The similar concentrations among the species, yet variation related to the ecology (age and trophic position) across individuals demonstrates the complexity of contaminant dynamics in freshwater fish in a large lake system and the need to consider variation across individuals within species. Environ Toxicol Chem 2021;40:3421-3433. © 2021 SETAC.

Abies alba has a high potential for mitigating climate change in European mountain forests, yet, its natural regeneration is severely limited by ungulate browsing. Here, we simulated browsing in a common garden experiment to study growth and physiological traits, measured from bulk needles, using a randomized block design with two levels of browsing severity and seedlings originating from 19 populations across Switzerland. Genetic factors explained most variation in growth (on average, 51.5%) and physiological traits (10.2%) under control conditions, while heavy browsing considerably reduced the genetic effects on growth (to 30%), but doubled those on physiological traits related to C storage. While browsing reduced seedling height, it also lowered seedlings’ water use efficiency (decreased δ13C) and N supply by mycorrhizal fungi as indicated by an increase in δ15N. Different populations reacted differently to browsing stress, and for Height, Starch and δ15N, population differences appeared to be the result of natural selection. We found that the fastest growing populations, originating from the warmest regions, decreased their needle starch level the most as a reaction to heavy browsing, suggesting a potential genetic underpinning for a growth-storage trade-off. Further, we found that seedlings originating from mountain populations growing on steep slopes had a significantly lower N discrimination in the common garden than those originating from flat areas, indicating that they have been selected to grow on N poor, potentially drained, soils. This finding was corroborated by the fact that N concentration in adult needles was lower on steep slopes than on flat ground, strongly indicating that steep slopes are the most N poor environments. Seedlings from these poor environments generally had a low growth rate and high storage, thus might be slower to recover from browsing stress than fast growing provenances from the warm environments with developed soils, such as the Swiss plateau.

Although research on microplastics (MPs) has evolved rapidly in recent years, researchers do not yet have a complete understanding of how MPs are impacting ecosystems. The effects of MP exposure are highly variable according to exposed species and MP traits. For example, aquatic zooplankton and smaller fishes that visually select their food might be more likely to ingest MPs due to resemblance to food items. Smaller-bodied animals also tend to contain higher concentrations of MPs by body weight in their digestive tracts and organs. In high enough concentrations, MPs might act to restrict energy flow through food webs by reducing the nutritional value of prey species, whether by food dilution, direct toxicity increasing homeostatic costs, or reductions in abundance. In this work, we used two in-lake, large mesocosm experiments to explore how exposure to microplastics affected the composition of essential food web nutrients – fatty acids – in yellow perch (Perca flavescens) and zooplankton. We found that MP concentration did not affect fatty acid composition in the fish and zooplankton when supplemental fish food was provided. However, preliminary findings from the second experiment suggest that body weight was lower in fish exposed to 29,240 particles L-1 MP concentrations when supplemental feeding was not provided. We will discuss how MPs might affect food webs by disrupting the flow of energy, how food webs might differ in resilience to these effects, our results so far from the experiments, and our future work on MPs and food webs. Also see: https://micro2022.sciencesconf.org/427376/document, In MICRO 2022, Online Atlas Edition: Plastic Pollution from MACRO to nano

Funder: University of South Florida; Id: http://dx.doi.org/10.13039/100008900, Funder: Royal Society Wolfson Merit Award, Glacier meltwater supplies silicon (Si) and iron (Fe) sourced from weathered bedrock to downstream ecosystems. However, the extent to which these nutrients reach the ocean is regulated by the nature of the benthic cycling of dissolved Si and Fe within fjord systems, given the rapid deposition of reactive particulate fractions at fjord heads. Here, we examine the benthic cycling of the two nutrients at four Patagonian fjord heads through geochemical analyses of sediment pore waters, including Si and Fe isotopes (δ30Si and δ56Fe), and reaction-transport modeling for Si. A high diffusive flux of dissolved Fe from the fjord sediments (up to 0.02 mmol m-2 day-1) compared to open ocean sediments (typically 0.1 mmol m-2 day-1). High pore water δ30Si (up to +3.3‰) observed near the Fe(II)-Fe(III) redox boundary is likely associated with the removal of dissolved Si by Fe(III) mineral phases, which, together with high sedimentation rates, contribute to the low diffusive flux of Si at the sampled sites. Our results suggest that early diagenesis promotes the release of dissolved Fe, yet suppresses the release of dissolved Si at glaciated fjord heads, which has significant implications for understanding the downstream transport of these nutrients along fjord systems.

In this study we present the results of isotopic analysis (δ13C, δ15N y δ18O) of human and faunal bones recovered in Guarani archaeological sites located in the rainforest of the center of the state of Rio Grande do Sul (Brazil). The isotopic values obtained in prey reflect a predominantly C3 or monoisotopic C3 pattern, both among herbivores and terrestrial omnivores, while a mixed pattern is observed for fish. The values of the spacing of the carbon sources and the values of δ15N reflect differences between each respective guild, which are within expected values. Humans have a diet based mostly based on C3 proteins and minor contribution of C4 proteins, with a significant intake of C4 carbohydrates, which, given the archaeological context, must correspond to the consumption of maize. The isotopic values of the diet of humans are equivalent to those observed in other individuals recovered at sites of this archaeological unit, located in other regions of Brazil as well as in Argentina and Paraguay. The results obtained in oxygen-18 are those expected for the region east of the Uruguay River, whose surface water comes from the precipitation of the Intertropical Convergence Zone and the South Atlantic Convergence Zone.

Foxtail and broomcorn millets are the most important crops in northern China since the early Neolithic. However, little evidence is available on how people managed these two crops in the past, especially in prehistory. Previous research on major C3 crops in western Eurasia demonstrated the potential of stable carbon and nitrogen isotope analysis of charred archaeobotanical remains to reveal the management of water and manure, respectively. Here, we evaluate the feasibility of a similar approach to C4 millets. Foxtail and broomcorn millet plants grown in pots in a greenhouse under different manuring and watering regimes were analysed to test the effects of management on stable carbon and nitrogen isotope values of grains. Stable nitrogen isotope values of both millets increased as manuring level increased, ranging from 1.7 ‰ to 5.8 ‰ in different conditions; hence, it appears a feasible tool to identify manuring practices, in agreement with results from recent field studies. However, the two millets exhibit opposing trends in stable carbon isotope values as watering level increased. The shift in stable carbon isotope values of millets is also smaller than that observed in wheat grown in the same experimental environment, making it difficult to identify millet water status archaeologically. In addition, we charred millet grains at different temperatures and for varying durations to replicate macro-botanical remains recovered archaeologically, and to evaluate the offsets in carbon and nitrogen isotope values induced by charring. We found that the stable nitrogen isotope values of foxtail millet and broomcorn millet can shift up to 1–2 ‰ when charred, while the stable carbon isotope values change less than 0.3 ‰. Overall, we demonstrate that stable nitrogen isotope values of charred foxtail and broomcorn millet seeds could provide insight into past field management practices, and both carbon and nitrogen isotope values can together inform palaeodietary reconstruction.

Exposure to persistent organic pollutants (POPs), such as organochlorines (OCs) and polybrominated diphenyl ethers (PBDEs), is associated with adverse health effects in wildlife. Many POPs have been banned and conse quently their environmental concentrations have declined. To assess both temporal trends of POPs and their detrimental impacts, raptors are extensively used as biomonitors due to their high food web position and high contaminant levels. White-tailed eagles (WTEs; Haliaeetus albicilla) in the Baltic ecosystem represent a sentinel species of environmental pollution, as they have suffered population declines due to reproductive failure caused by severe exposure to dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCB) during the 1960s through 1980s. However, there is a lack of long-term studies that cover a wide range of environmental contaminants and their effects at the individual level. In this study, we used 135 pooled samples of shed body feathers collected in 1968–2012 from breeding WTE pairs in Sweden. Feathers constitute a temporal archive for substances incorporated into the feather during growth, including corticosterone, which is the primary avian glucocorticoid and a stress-associated hormone. Here, we analysed the WTE feather pools to investigate annual variations in feather corticosterone (fCORT), POPs (OCs and PBDEs), and stable carbon and nitrogen isotopes (SIs; dietary proxies). We examined whether the expected fluctuations in POPs affected fCORT (8–94 pg. mm− 1 ) in the WTE pairs. Despite clear temporal declining trends in POP concentrations (p < 0.01), we found no sig nificant associations between fCORT and POPs or SIs (p > 0.05 in all cases). Our results do not support fCORT as a relevant biomarker of contaminant-mediated effects in WTEs despite studying a highly contaminated popu lation. However, although not detecting a relationship between fCORT, POP contamination and diet, fCORT represents a non-destructive and retrospective assessment of long-term stress physiology in wild raptors other wise not readily available.

International audience; The involvement of meteoric water in orogens dynamics through surface processes is well known as for example in the Himalayas where erosion, resulting of the interplay between climate and tectonics shapes the most spectacular landscapes on the planet. But what about more internal and deepest surface fluid infiltration? Here we report analysis of the δ18O(water)and δD(water)of extracted water from fluid inclusions hosted into Cenozoic quartz veins sampled in the core of the Himalayan range, near the Main Central Thrust and the South Tibetan Detachment. Isotopic and microthermometric values suggest a meteoric origin for the fluids trapped in the quartz of syn-to post-kinematic veins formed between 10 to 20 km depth. Moreover, the isotopic compositions obtained in this study on quartz fluid inclusions water collected along a transect across the Himalayan range evolved with the topography in a similar manner than the modern meteoric water. Considering the age of formation of the quartz veins between 18 and 12 Ma, we deduce that the morphology of the Himalayan topographic front was already shaped during the Miocene but located further north.

Energy flows from land to sea and between pelagic and benthic environments have the potential to increase the connectivity between estuaries and adjacent ecosystems as well as among estuarine habitats. To identify such energy flows and the main trophic pathways of energy transfer in the Minho River estuary, we investigated the spatial and temporal fluctuations of carbon and nitrogen stable isotope ratios in benthic (and their potential food sources) and epibenthic consumers. Sampling was conducted along the estuarine salinity gradient from winter to summer of 2011. We found that the carbon (delta 13C = 13C/12C) and nitrogen (delta 15N = 15N/14N) stable isotope ratios of the most abundant benthic and epibenthic consumers varied along the salinity gradient. The delta 13C values increased seaward, whereas the opposite pattern was found for the delta 15N, especially during the summer. The stable isotope ratios revealed two trophic pathways in the Minho estuary food web. The first pathway is supported by phytoplankton and represented by filter feeders such as zooplankton and some deposit feeders, particularly amphipods and polychaetes. The second pathway is supported by detritus and composed essentially of deposit feeders, which by being consumed, allow detritus to be incorporated into higher trophic levels. Spatial and temporal feeding variations in the estuarine benthic food web are driven by hydrology and proximity to adjacent ecosystems (terrestrial, marine). During high river discharge periods, the delta 13CPOC (ca. -28 parts per thousand) and C: NPOM (>10) values suggested an increase of terrestrial-derived OM to the particulate OM pool, which was then used by suspension feeders. During low river discharge periods, marine intrusion increased upriver, which was reflected in benthic consumers' 13C-enriched stable isotope values. No relationship was found between food quality (phytoplankton vs. detritus) and food chain length because the lowest and highest values were associated with freshwater and saltmarsh areas, respectively, both dominated by the detrital pathway. This study demonstrates that benthic consumers enhance the connectivity between estuaries and its adjacent ecosystems by utilizing subsidies of terrestrial and marine origin and that benthic-pelagic coupling is an important energy transfer mechanism to the benthic food web. info:eu-repo/semantics/publishedVersion

13 pages, 4 figures, supporting Information https://doi.org/10.1111/ecog.05606.-- Data availability statement: Data available from the Dryad Digital Repository: https://dx.doi.org/10.5061/dryad.zs7h44j8s (Figuerola et al. 2021), Coastal hypoxia has become an increasingly acknowledged threat to coral reefs that is potentially intensifying because of increased input of anthropogenic nutrients. Almirante Bay (Caribbean Panama) is a semi-enclosed system that experiences hypoxia in deeper waters which occasionally shoals onto shallow coral reefs, suffocating most aerobic benthic life. To explore the long-term history of reefs in the bay we extracted reef matrix cores from two reefs that today experience contrasting patterns of oxygenation. We constructed a 1800-year-long record of gastropod assemblages and isotope compositions from six U-Th chronologically-constrained reef matrix cores. We extracted two cores from each reef at 3 m water depth and two additional cores from a deeper part (4.8 m) of the hypoxia-exposed reef. Results show that the deeper part of the hypoxic reef slowed in growth and stopped accreting approximately 1500 years BP while the shallow part of the reef continued to accrete to the present day, in agreement with a model of expanding hypoxia at this time. Our proxy-based approach suggests that the patterns of increasing herbivores and decreasing carbon isotope values in the deeper part of the hypoxic reef may have been driven by an increase in hypoxia via eutrophication caused by either natural changes or human impacts. Similar patterns in these paleoindicators occurred in the shallow part of the hypoxic reef during the last few decades. This suggests that the deep water hypoxia may be expanding to depths as shallow as 3 m and that shallow reefs are at greater risk due to increased human activity, This project and the research visit of BF to Texas A&M Univ. were financially supported by the Secretaría Nacional de Ciencia y Tecnología e Innovación (SENACYT; 47-2017-4-FID16-239), Sistema Nacional de Investigación (SENACYT), the Scholarly Studies Program (Smithsonian Institution), Smithsonian Tropical Research Institute (STRI), Texas A&M University and donations from M. Selin and family, J. Bilyk, V. and B. Anders, J. and M. Bytnar and the Young Presidents Organization (Los Angeles Gold Chapter). BF was supported by a STRI postdoctoral fellowship and the postdoctoral fellowships programme Beatriu de Pinós funded by the Secretary of Universities and Research (Government of Catalonia) and by the Horizon 2020 programme of research and innovation of the European Union under the Marie Skłodowska-Curie grant agreement no. 801370 (Incorporation grant 2019 BP 00183) and the Juan de la Cierva programme funded by the Ministry of Science and Innovation (Incorporation grant IJCI-2017-31478). With the institutional support of the ‘Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S)

In this paper we discuss recent developments in documenting the spread of millet across the Eurasian steppes. We emphasize that, despite a recent proposal that millet consumption in southern Siberia can be attributed to the Early Bronze Age (i.e., the late third to early second millennium BC), at present there are no direct data for southern Siberia indicating the consumption of millet prior to the Late Bronze Age, from the 14th century BC. We also present in full the combined stable isotope and 14C datasets from the Minusinsk Basin to support this conclusion.

Individual specialization within populations is increasingly recognized as important in both ecology and evolution, but researchers working on intraspecific variation in behavior and diet infrequently interact. This may be because individual specialization on diet and behavior was historically difficult to investigate simultaneously on the same individuals. However, approaches like stable isotope analysis that allow hindcasting past field diets for laboratory organisms may provide opportunities to unite these areas of inquiry. Here, we tested the role of intraspecific competition on individual specialization through analysis of both behavior and diet simultaneously. We focused on intraspecific competition as a mechanism that might drive individual specialization of both diet and behavior. We conducted this study in Vilas County, Wisconsin, United States (US), using rusty crayfish Faxonius rusticus from six lakes across a relative abundance gradient. We conducted six assays to measure individual specialization of behavior and used stable isotope analysis to measure individual specialization of diet. We then related both measures of individual specialization to relative abundance of F. rusticus using linear and quadratic models. We found a unimodal relationship between intraspecific competition and individual specialization of diet for F. rusticus, likely because some preferred resources are unavailable to specialize on at the highest densities of this well‐studied crayfish invader. Conversely, we found greater support for a linear relationship between individual specialization of behavior and intraspecific competition, perhaps because specialization by behavior is not inherently resource‐limited. Our results show that dietary and behavioral specialization may exhibit different responses to increased intraspecific competition, and demonstrate a potential technique that can be used to investigate individual specialization of diet and behavior simultaneously for the same individuals and populations., Individual specialization within populations is increasingly recognized as important in both ecology and evolution, but researchers working on intraspecific variation in behavior and diet infrequently interact. Here, we tested the role of intraspecific competition on individual specialization through analysis of both behavior and diet simultaneously. We found a unimodal relationship between intraspecific competition and individual specialization of diet for populations of an invasive crayfish, but we found greater support for a linear relationship between individual specialization of behavior and intraspecific competition, perhaps because specialization by behavior is not inherently resource‐limited.

Migratory shorebirds are among the most threatened groups of birds. They rely on natural intertidal habitats outside the breeding season, but, to some extent have adjusted to using man-made habitats. Here, we assessed the importance of coastal saltpans – a type of anthropogenic wetland – for feeding in migratory shorebirds during their northward migration along the East Asian-Australasian Flyway (EAAF). We combined low tide counts on intertidal flats and nearby saltpans at the Luannan coastal wetland complex (Bohai Bay, China) with Bayesian mixing model analyses (BMMs) based on stable isotopes to evaluate the relative importance of coastal saltpans versus natural intertidal habitats as foraging grounds for migrating species. We grouped shorebird species (n = 24) according to feeding guild and body size, and found that both predictors explained the broad-scale patterns of foraging use of saltpans by shorebirds at low tide. The guild of water-surface foraging species (e.g. stilts and avocets), independently of body size, mostly fed in saltpans, and the small-medium visual (e.g. plovers) and tactile-surface (e.g. sandpipers) foraging species consumed a significant portion of their diet in this habitat. In contrast, most large tactile-surface foraging species barely foraged in saltpans at low tide. BMMs showed that shorebirds had a greater reliance on saltpans than did traditional counts of foraging birds in each habitat at low tide. Saltpan food is rich in essential fatty acids, so the contribution of saltpans to the diet of shorebirds should not be considered only in absolute values, but also in the quality of this contribution. Saltpans may therefore help conserve declining shorebirds if properly managed – for example by controlling water levels – to serve the specific feeding guilds that rely on them. While our focus is in the EAAF, the findings are relevant for other flyways and other non-tidal anthropogenic wetlands.

The massive ice (MI) bodies are widespread phenomena on Chukotka coastal plains. Although they have been studying since 1930s, stable isotope method was applied for the ice beds quite recently. In this study cryostratigraphy and stable oxygen and hydrogen isotope composition of MI bodies on the extreme North-Eastern Chukotka (near Lavrentiya settlement and Koolen’ lake) have been studied in detail. It was concluded that studied MI bodies have intrasedimental origin and most likely are dated back to the Late Pleistocene age. Mean δ18O values range from –18.5 ‰ to –15 ‰ whereas mean δ2 H values range from –146‰ to –128 ‰ that is higher than expected for the Late Pleistocene ice bodies in this region, which most likely resulted from isotopic fractionation during freezing of water-saturated sediments in a closed system when forming ice became isotopically enriched compared with initial water. The analysis of co-isotope ratios for MI shows that initial water is mainly of meteoric origin (precipitation, water of lakes and taliks).

For top consumers in marine environments, trophic discrimination factors (∆13C and ∆15N) between food and consumers’ tissues are expected to be similar among related species. However, few studies conducted in the laboratory indicate a large variability among species, which should be potentially higher in free-ranging animals. Here, we test for differences in tissue-specific ∆13C and ∆15N values of two wild penguin species (Chinstrap Pygoscelis antarctica and Gentoo P. papua) breeding in sympatry at Livingston Island, Antarctica. A total of 41 adults and 28 chicks, and food items comprised exclusively by Antarctic krill (Euphausia superba, n = 22) in Chinstraps and almost exclusively in Gentoos, were sampled for stable isotope analyses. Overall, Δ13C values varied between -1.8 and 4.0 ‰ and Δ15N values ranged from 1.2 to 6.1 ‰, and these differed between species, tissues and age-classes. Δ13C in adult penguins differed between species for feather and blood. Species-specific differences in Δ13C and Δ15N were seen in chick nail and muscle, while only Δ13C values differed between species in feathers. Our results show that trophic discrimination factors can differ substantially between closely related spe- cies consuming similar prey, especially in Δ13C value. Variation in Δ13C was driven by species, tissue and age-class, while variation in Δ15N was mostly driven by tissue type. Trophic discrimination factors may be associated to physiological and/or stress factors which may fluctuate in the wild, and this was particularly evident on chicks. This study highlights the use of diet-specialised species for the determination of trophic discrimination factors in the wild., This study benefitted from the strategic programme of MARE, financed by FCT (MARE—UID/MAR/04292/2020). FRC acknowledges the transitory norm contract (DL57/2016/CP1370/CT90) and JS the PhD Grant (SRFH/PD/BD/113487/2015) financed by the Foundation for Science and Technology (FCT; Portugal) and the European Social Fund (POPH, EU).