Search

The inexplicable distribution of souring wells (presence of H2S gas) of the unconventional Montney Formation hydrocarbon resource (British Columbia; BC) is investigated by analysing sulphur and oxygen isotopes, coupled with XRD mineralogy, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX). The sulphur isotopic analysis indicates that the sulphur isotopic range for Triassic anhydrite (δ34S 8.9 to 20.98‰ VCDT) is the same as the H2S sulphur that is produced from the Montney Formation (δ34S 9.3 to 20.9‰ VCDT). The anhydrite in the Triassic rocks is the likely source of the sulphur in the H2S produced in the Montney Formation. The deeper Devonian sources are enriched in 34S and are not the likely source for sulphur (δ34S 17.1 and 34‰ VCDT). This is contradictory to studies on Montney Formation producers in Alberta, with heavier (34S-enriched) sulphur isotopic signatures in H2S gas of all souring Montney Formation producers. These studies conclude that deep-seated faults and fractures have provided conduits for sulphate and/or H2S gas to migrate from deeper sulphur sources in the Devonian strata. There are several wells that show a slightly heavier (34S-enriched) isotopic signature (δ34S 18 to 20‰ VCDT) within the Montney Formation H2S gas producing within close proximity to the deformation front. This variation may be due to such deep-seated faults that acted as a conduit for Devonian sulphur to migrate into the Montney Formation. Our geological model suggests the sulphate-rich fluids have migrated from the Charlie Lake Formation prior to hydrocarbon generation in the Montney Formation (BC). Sulphate has concentrated in discrete zones due to precipitation in conduits like fracture and fault systems. The model fits the observation of multi-well pads containing both sour- and sweet-producing wells indicating that the souring is occurring in very narrow and discrete zones with the Montney Formation (BC). Government agencies and operators in British Columbia should map the anhydrite-rich portions of the Charlie Lake Formation, together with the structural elements from three-dimensional seismic to reduce the risk of encountering unexpected souring. [ABSTRACT FROM AUTHOR]

Libkovice is a village in the northwestern Czech Republic that was demolished at the end of the last century due to the expansion of a nearby mine. The former church cemetery has been a subject to bioarchaeological excavation and research, where some 850 burials from the 13th to the 19th Century have been discovered so far. With the application of stable isotope analysis, it has also been possible to uncover the dietary patterns of this exemplary rural Central European community, which was the aim of this study. The materials analysed here consist of samples from long bones of 56 burials and 18 animal bones discovered in Libkovice during the 2019/21 excavations. It has been employed stable carbon (δ13C) isotope analysis to determine the average contributions of foods derived from the C3 plants. Statistically significant differences were found between the analyzed fauna and human samples for nitrogen (F=47.4 p

The inexplicable distribution of souring wells (presence of H2S gas) of the unconventional Montney Formation hydrocarbon resource (British Columbia; BC) is investigated by analysing sulphur and oxygen isotopes, coupled with XRD mineralogy, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX). The sulphur isotopic analysis indicates that the sulphur isotopic range for Triassic anhydrite (δ34S 8.9 to 20.98‰ VCDT) is the same as the H2S sulphur that is produced from the Montney Formation (δ34S 9.3 to 20.9‰ VCDT). The anhydrite in the Triassic rocks is the likely source of the sulphur in the H2S produced in the Montney Formation. The deeper Devonian sources are enriched in 34S and are not the likely source for sulphur (δ34S 17.1 and 34‰ VCDT). This is contradictory to studies on Montney Formation producers in Alberta, with heavier (34S-enriched) sulphur isotopic signatures in H2S gas of all souring Montney Formation producers. These studies conclude that deep-seated faults and fractures have provided conduits for sulphate and/or H2S gas to migrate from deeper sulphur sources in the Devonian strata. There are several wells that show a slightly heavier (34S-enriched) isotopic signature (δ34S 18 to 20‰ VCDT) within the Montney Formation H2S gas producing within close proximity to the deformation front. This variation may be due to such deep-seated faults that acted as a conduit for Devonian sulphur to migrate into the Montney Formation. Our geological model suggests the sulphate-rich fluids have migrated from the Charlie Lake Formation prior to hydrocarbon generation in the Montney Formation (BC). Sulphate has concentrated in discrete zones due to precipitation in conduits like fracture and fault systems. The model fits the observation of multi-well pads containing both sour- and sweet-producing wells indicating that the souring is occurring in very narrow and discrete zones with the Montney Formation (BC). Government agencies and operators in British Columbia should map the anhydrite-rich portions of the Charlie Lake Formation, together with the structural elements from three-dimensional seismic to reduce the risk of encountering unexpected souring.

Context: Global environmental modification is placing increased demand on taxonomic resources, especially herbarium collections, which are being utilised for information and as biological resource material in ways never previously envisaged. This increased use of herbarium collections presents current and on-going management challenges. Aims: To demonstrate, with two Australian studies, the essential role of herbarium collections in investigating long-term pollution; to emphasise the importance of on-going collecting for herbaria and make recommendations for future collection management. Methods: Australian case studies of a long-term pollution problem are used to show how verified lichen and fungal taxa in Australian herbaria were crucial in identifying sources of air pollution over time. Key results: Chemical and isotopic analyses of lead in samples from curated herbarium collections were used to reconstruct patterns of atmospheric lead deposition over 150 years in eastern Australia. This extended time series of samples facilitated documentation of the full cycle from natural background concentrations to the introduction and increasing usage of lead both in industry and motor vehicles, to the eventual discontinuation of its use in automotive fuel. In addition to demonstrating the value of regular, long-term sampling of selected taxa and potential applications to emerging environmental problems, the importance of strict protocols for destructive sampling and analysis of herbarium specimens, especially for older collections containing small quantities of material, has been highlighted. Conclusions: Both the Australian and previous studies have identified a number of problems and potential challenges to maintaining and maximising the utilisation of finite herbarium resources for the future. While acknowledging that Australasian herbaria have well documented policies and protocols for studies that sample their collections, six recommendations are made, for future implementation as appropriate. Implications: Current management strategies for finite reference collections are summarised and recommendations for the future include the following: repeated, ongoing collecting over broader areas; periodic re-collection of larger samples from select reference sites with detailed field data; preparation and storage of specimens under controlled environmental conditions, with minimal chemical pest control; utilisation of common widespread taxa for research; careful supervision of destructive sampling techniques to assess compounds present; and adequate funding to facilitate the digitisation of herbarium specimens to increase access and optimise use of curated collections. A photograph of Cladonia lichen growing on soil. Chemical and isotopic analyses of lead in lichen and fungal herbarium collections were used to reconstruct patterns of deposition over a period of 150 years in eastern Australia. The central role of herbaria in two case studies of temporal changes in atmospheric lead pollution is discussed and used to address future collection management challenges. Photograph by Dr Xinyu Wang. [ABSTRACT FROM AUTHOR]

In this study, we present the hydrogeological, hydrogeochemical and isotopic characterisation and monitoring activity of a closed landfill located in the northern sector of the Phlegrean Fields groundwater body in the Campania Region (Southern Italy). The aim of the study is to distinguish between natural enrichments (e.g., geogenic sources) and anthropogenic pressures (e.g., leakages from the landfill body) causing anomalously high concentrations of some metals (As, F, Fe, Mn) in groundwater. Major anions, cations, metals, water-stable isotopes, carbon isotopes and tritium were analysed. The results show that high As, F and Fe concentrations are due to adsorption–desorption processes occurring in the aquifer hosted in the volcanic rocks/deposits or the occurrence of upwelling hydrothermal fluids related to the volcanic activity of the Phlegrean Fields, which may cause metal mobilisation. High localised Mn concentrations cannot be solely related to natural processes or to groundwater contamination due to leachate leakage from the landfill body. Instead, we hypothesise a leakage from the landfill gas system. The outcomes of this study show the advantages of the coupled use of physico-chemical and isotopic analyses in improving the comprehension of geochemical processes in areas characterised by the presence of municipal landfills. [ABSTRACT FROM AUTHOR]

Libkovice is a village in the northwestern Czech Republic that was demolished at the end of the last century due to the expansion of a nearby mine. The former church cemetery has been a subject to bioarchaeological excavation and research, where some 850 burials from the 13th to the 19th Century have been discovered so far. With the application of stable isotope analysis, it has also been possible to uncover the dietary patterns of this exemplary rural Central European community, which was the aim of this study. The materials analyzed here consist of samples from long bones of 56 burials and 18 animal bones discovered in Libkovice during the 2019/21 excavations. It has been employed stable carbon (δ13C) isotope analysis to determine the average contributions of foods derived from the C3 plants. Statistically significant differences were found between the analyzed fauna and human samples for nitrogen (F=47.4 p<0.05) and carbon (F=19.18 p<0.05). There were no statistically significant differences in the analyzed animal and human samples between the specify centuries. When considering the ages of various human individuals, the results indicated statistically significant differences in nitrogen isotopes (F= 7.71 p<0.05) between children from the infants I group and older children together with adults from the Middle Ages, as well as between children from the infants I group and adults (F= 3.3, p<0.05) from the modern times. The proportion of food from C3 plants that made up the diets of the studied population was on average 89%, and the potential proportion of freshwater fish in the diet could be higher than 80%. The similarity between the chronologically diverse groups may indicate similar strategies for food acquisition. The results obtained for the population of Libkovice are very similar to the diets of the populations living in Central Europe broadly during the two periods. [ABSTRACT FROM AUTHOR]

The elemental and isotopic abundances of krypton and xenon provide critical insights into processes ranging from stellar nucleosynthesis to volatile accretion and paleotemperatures on Earth. Accurate and precise determination of the krypton and xenon elemental abundance and isotopic ratios requires sample purification and noble gas separation to avoid interferences in the mass spectrometer. However, effective separation of krypton (Kr) from argon (Ar) and xenon (Xe) has remained challenging. Here, we present a new cryogenic instrument associated with a new protocol to achieve an efficient and effective separation of Kr from Ar and Xe. Using two electropolished stainless steel cryogenic traps on a single cold head, distillation of the noble gases from one trap onto the other and temperature cycling of the traps to reduce the effect of cryotrapping allows ≥ 98 % of the Kr in a sample to be recovered with < 0.5 % of the Ar and < 1 % of the Xe abundances of the sample. Likewise, more than 99 % of the Xe fraction can be recovered with < 1 % Kr. No variations in the isotopic ratios of the separated Kr and Xe fractions are observed as a function of the signal size for air standards. Moreover, we find that krypton isotopes can be fractionated during Ar-Kr separation. We suggest that more accurate krypton isotopic compositions can be obtained by maximizing the recovered krypton fraction instead of minimizing the argon fraction within krypton.

Copyright of Archaeology & Science / Arheologija i Prirodne Nauke is the property of Institute of Archaeology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In countless modern geochemical studies, diverse biological and geologic samples are analyzed for Sr, Nd, and Pb isotopic composition. Such heterogeneity presents challenges for a "one-size-fits-all" approach to sample preparation, necessitating customization of sample preparation and chromatographic separation methods. We present (1) digestion techniques for low-Nd silicates, carbonatites, carbonates, water, plant and wood material, organic soils, aerosols collected via filtration, as well as archaeological samples (alloys, teeth, and bones) (2) a column chromatographic approach for samples with low concentrations (large amounts of a matrix) and (3) method verification via replicate analyses of a wide variety of isotopic standards. [ABSTRACT FROM AUTHOR]

Lithostratigraphy and isotopes of Paleogene sequences consisting mainly of terrestrial clastics and limestone were examined in the northern Fergana Basin of Uzbekistan. The studied sections consisted of two facies: the lower sequence coarse-grained terrestrial clastics and the upper sequence limestone clastics characterized by limestone beds. The sulfur isotopic composition of the bivalve obtained from the lower sequence was relatively low, namely, 14.94–16.82‰, which is equivalent to the Early Cretaceous; however, it is possible that the isotopic composition differed from that obtained in open seawater due to the presence of terrestrial clastics and the freshwater effect. In contrast, the sulfur isotopic composition of limestone from the upper sequence was relatively high, namely, 19.37–21.19‰, thereby indicating that they were likely to originate from the Early to Middle Eocene. Furthermore, the strontium isotopic compositions of the lower and upper sequences were 0.707772–0.707875‰ and 0.707812–0.708063‰, respectively. These values are more similar to those of the Paleogene than the Cretaceous. Finally, lithostratigraphy and age determination allowed us to correlate the upper sequence with representative limestone from the fourth transgression of the proto-Paratethys Sea, whilst the limestone beds were deduced to be remnants of the Eocene marine incursion of the proto-Paratethys Sea. [ABSTRACT FROM AUTHOR]

Lithostratigraphy and isotopes of Paleogene sequences consisting mainly of terrestrial clastics and limestone were examined in the northern Fergana Basin of Uzbekistan. The studied sections consisted of two facies: the lower sequence coarse-grained terrestrial clastics and the upper sequence limestone clastics characterized by limestone beds. The sulfur isotopic composition of the bivalve obtained from the lower sequence was relatively low, namely, 14.94–16.82‰, which is equivalent to the Early Cretaceous; however, it is possible that the isotopic composition differed from that obtained in open seawater due to the presence of terrestrial clastics and the freshwater effect. In contrast, the sulfur isotopic composition of limestone from the upper sequence was relatively high, namely, 19.37–21.19‰, thereby indicating that they were likely to originate from the Early to Middle Eocene. Furthermore, the strontium isotopic compositions of the lower and upper sequences were 0.707772–0.707875‰ and 0.707812–0.708063‰, respectively. These values are more similar to those of the Paleogene than the Cretaceous. Finally, lithostratigraphy and age determination allowed us to correlate the upper sequence with representative limestone from the fourth transgression of the proto-Paratethys Sea, whilst the limestone beds were deduced to be remnants of the Eocene marine incursion of the proto-Paratethys Sea.

In our research we summarized data obtained on the composition, structure, and geochemical characteristics of the granitoid plutons of the eastern part of the Krasnoleninsky arch of the East Siberian Plate and the age of rocks surrounding them. The Kamenny, Palyanovsky, North Kamenny and Vodorazdelny granite, granodiorite, and granosyenite plutons were emplaced in the interval of 297–261 Ma (Early–Late Permian) as melting products of the lower–middle crust at the postorogenic stage. The formation of granitoid massifs in the basement of the Em-Egovsky summit took place in the Late Devonian (Frasnian, Famennian). They differ greatly from the rocks of the Kamenny pluton in composition, degree of secondary alterations, and tectonization. [ABSTRACT FROM AUTHOR]

In 2014, the unexpected discovery of some mass graves shed light on the earliest days of the newly founded city of Saint Petersburg. The graves could be dated to the beginning of the 18th century, and analyses of the 255 excavated skeletons indicate that the individuals buried there were some of the workers who were forced to the construction sites and contributed tobuilding early Saint Petersburg. In this article, we aim to examine the possible origins of the workers and their general living conditions, including pathologies, diet and nutrition. For this, we will use various methods from archaeology, anthropology and isotopic analyses, and we will give some insights into the lives of those people. [ABSTRACT FROM AUTHOR]

The Mount Colin Cu-Au deposit is located in the Mary Kathleen Domain of the Mount Isa Inlier, NW Queensland. The deposit is hosted in the Corella Formation, which transitions into the Burstall Granite at a depth of ~400 m. The host rocks of the deposit are overprinted by Na-Ca alteration and a Ca-Mg-Fe skarn assemblage. Na-Ca alteration yields a titanite 207Pb/206Pb weighted mean age of 1717 ± 8 Ma (MSWD = 0.32) and is composed of albite, actinolite, zircon, titanite and scapolite with retrograde calcite, prehnite and sericite. The Ca-Mg-Fe skarn yields a titanite 207Pb/206Pb weighted mean age of 1712 ± 7 Ma (MSWD = 1.2) and is composed of hastingsite, K-feldspar, clinopyroxene, albite, titanite, calcite, biotite, and zircon with retrograde quartz and chlorite. Based on temporal relationships, Na-Ca alteration and the Ca-Mg-Fe skarn is interpreted to have formed from a hydrothermal magmatic fluid during late-stage magmatism of the (1740–1710 Ma) Wonga-Burstall plutons. A second generation of titanite (denoted titanite II) is present within Na-Ca alteration and the Ca-Mg-Fe skarn assemblage. Titanite II yields a 207Pb/206Pb weighted mean age of 1576 ± 7 Ma (MSWD = 0.37), and is interpreted to have formed from an external metamorphic hydrothermal fluid during widespread deformation associated with the (1610–1500 Ma) Isan Orogeny. The Mount Colin Cu-Au deposit consists of a predominantly coarse-grained, mineralogically zoned assemblage that infills along the NW-striking Mount Colin Fault. The centre of the deposit comprises a largely unmineralized core composed of calcite and/or quartz ± apatite ± microcline. Cu-Au mineralization is positioned along the outer margins of the deposit and consists of biotite, actinolite, chalcopyrite and pyrrhotite with trace abundances of magnetite, pyrite, galena, melonite and arsenopyrite. Apatite from the core of the deposit yields a U–Pb age of 1523 ± 16 Ma (MSWD = 1.2). The δ34S CDT values of chalcopyrite and pyrrhotite range from 0.1–2.1 ‰ and 0.9–1.5 ‰ respectively. The δ13C VPDB values of calcite range from −5.54 ‰ to −4.54 ‰ with corresponding δ18O VSMOW values ranging from 8.16–11.26 ‰. Based on the temporal and isotopic constraints presented in this study, a hydrothermal magmatic origin for Cu-Au mineralization is favoured. The timing of Cu-Au mineralization is coeval with a regional-scale metamorphic/hydrothermal event throughout the Mary Kathleen Domain and widespread magmatism throughout the Eastern Fold Belt of the Mount Isa Inlier. [Display omitted] • Na-Ca alteration & Ca-Mg-Fe skarn surrounding the deposit formed at ca. 1715 Ma. • Syn-metamorphic titanite formed within these alteration assemblages ca. 1575 Ma. • Cu-Au mineralization formed at ca. 1520 Ma. • S-, O- and C- isotope signatures reflect a hydrothermal-magmatic fluid source. [ABSTRACT FROM AUTHOR]

We describe here the first combined isotopic and impurities study on 27 copper artefacts found in the north‐west of Spain. This study follows previous studies on the lead isotopic composition of copper ores in three local mines that were exploited during the Bronze Age. The levels of impurities found were clearly different from ingots and axes, with ingots having much higher levels of impurities. It was not possible to differentiate the origin of the artefacts only by the impurities present. On the other hand, the lead isotopic composition indicated that all artefacts were prepared from local ores, the 'La Profunda' mine being the most probable source for most artefacts that carried out a clear radiogenic lead signature. The copper isotopic composition seemed to be able to differentiate artefacts from the 'El Aramo' mine from those from the 'El Milagro' and 'La Profunda' mines. On the other hand, the antimony isotopic signature was not useful for source allocation. [ABSTRACT FROM AUTHOR]

The paper aims at reconstructing the paleodiet of the Early Bronze Age population in the Baraba forest-steppe area of Western Siberia (the Odino culture). The study is based on materials of three large necropoleis of Sopka 2/4A, Tartas 1 and Preobrazhenka 6. Two chronological groups of the Odino culture burials have been defined by radiocarbon dating which gives us an opportunity to research the structure and changes in the paleodiet during the 3rd millennium BC. Reconstructions of the paleodiet are based on paleozoological determinations (including bone artifacts) and analyses of carbon (δ13С) and nitrogen (δ15N) isotopes in human and faunal bones (including some modern faunal samples). Results of isotopic measurements indicate that fish had formed a basic food component in the subsistence of the Odino population throughout the 3rd millennium BC. High values of δ15N in mushrooms (Boletaceae) do not exclude their important role along with fish in the human diet. A secondary food source for the Odino people was meat of herbivores and possibly also omnivores. The main game animal for the Odino population was an elk. Higher δ13С values in human bones in the last third of the 3rd millennium BC indicate changes in food sources. Preliminary, we associate this signal with an increased consumption of animal products of more southern origins (steppe?) by Odino people, which might be a result of the emergence of domesticated animals in economy.

In this study, a characterization of particulate matter (PM 10 ) is performed in a suburban area in Northwestern Spain (A Coruña, Galicia), in order to establish the interrelationships between major components, as well as between these components and submicron particles. 140 PM 10 samples were collected from April 2014 to January 2015 and numerous chemical parameters, such as carbonaceous fraction, including water-soluble organic carbon (WSOC), major ions, and carbon and nitrogen isotopic ratios, were determined. Data on ultrafine particles for one season were also recorded. Nanoparticle modes showed a correlation between them and with all of the carbonaceous fractions (especially elemental carbon and Aitken mode) and some meteorological parameters (humidity and solar radiation). Their correlations suggested the possible influence of a few industrial sources, depending on the prevailing winds. Isotopic data indicated the presence of a significant input from combustion sources during the cold period and primary biogenic input during the spring, reinforced by OC/EC ratios and WSOC values. Organic carbon (OC), the main component of carbonaceous fraction, correlates seasonally with elemental carbon (EC), setting a fitting to a potential equation during the winter. These parameters also suggested a significant presence of secondary organic aerosol in the area, except in the spring. A high contribution of secondary inorganic aerosol was also observed, with ammonium sulfate (all of the seasons), sodium nitrate with a marine contribution (except in the autumn), and potassium sulfate (except in the spring) as the main species. The Atlantic Ocean's influence was observed as a contribution of sea salt to PM 10 of 23.4% on average, up to 84.5% on certain days, and a strong relationship between sea salt and secondary aerosol. [ABSTRACT FROM AUTHOR]

This study investigated nitrate attenuation in low-permeability sediments (LPS) in a multi-layer aquifer by integrating hydrochemical, isotopic and microbiological molecular techniques in a field site. In the meantime, the overlying high-permeability sediment (HPS) was also examined on the nitrate attenuation for the sake of comparison. Additionally, laboratory flow-through experiments were conducted to assess the overall nitrate reduction rate in the two types of sediment. The δ 15 N-NO 3 − and δ 34 S-SO 4 2 − values were more enriched by approximately 37‰ and 15‰ in the LPS than the overlying HPS associated with substantial reductions of the NO 3 − and SO 4 2 − concentration, indicating the occurrence of strong bio-reductions in nitrate and sulfate. The microbial community diversity analyses showed a higher diversity of the denitrifiers encoding nirS - (Shannon Index SI = 6.3) and nrf -type gene ( SI = 2.7), and the sulfate reduction bacteria (SRB) encoding the dsr gene ( SI = 6.4) in the LPS than in the HPS. The bacterial community structure was influenced by the groundwater hydrochemistry and the redox conditions. Due to the presence of anoxic groundwater with low levels of nutrients, the LPS featured higher abundances of nitrate reducers belonging to Alphaproteobacteria and SRB belonging to the strictly anaerobic class Clostridia relative to the HPS. Notably, chemolithotrophs were abundant in the LPS and likely coupled the reduction of nitrate with the oxidation of iron. Furthermore, the LPS was demonstrated to attenuate nitrate at a rate two times of the HPS in flow-through experiments, and denitrification accounted for approximately 93% of the nitrate reduction. The high nitrate reduction rate of the LPS was likely attributable to its high functional genes diversity. This study confirmed the occurrence of strong nitrate attenuation in the LPS. The LPS was found to play a significant role in protecting aquifers from anthropogenic contamination. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ecological control has often focused on factors enhancing control of pests by their natural enemies, while factors reducing the colonization rate of crops by pests have been comparatively neglected. We present an approach to assess landscape influence on the intensity of wheat colonization by a major crop pest, the aphid Rhopalosiphum padi. We used trays containing wheat seedlings to monitor field colonization by R. padi and barley yellow dwarf viruses' transmission in two areas in France in autumn. We assessed the influence of landscape components likely affecting aphid colonization, i.e. maize and grasslands as source of migrants on the number of aphids landing per tray, as well as the host plant of origin and the viruliferous potential of migrants. During the survey, maize was the main source of migrants. Virus transmission was detected in a few cases (4 % positive assays). Colonization was increased by the presence of maize, but reduced by the presence of grasslands at the landscape scale considered here (i.e. at a radius of 1000 m). Our study contributes to a better understanding of disease dynamics in agricultural landscapes. By identifying features of the landscape that surrounds fields and affects these dynamics, growers can develop more efficient crop protection strategies relying on habitat manipulation and rational use of pesticides. [ABSTRACT FROM AUTHOR]

Numerous active and fossil hydrothermal carbonate chimneys have been reported at Lake Asal and Lake Abhe, in the southeastern part of the Afar Rift (Republic of Djibouti): a tectonically and volcanically active region for the last 30 million years. In this study, we report on a detailed mineralogical and geochemical investigation of unusual hydrothermal mixed carbonate-siliceous chimneys recently discovered in the Allols area (Harralol, Haralé Awda and Sakallol), northwest of the Asal Rift. These inactive chimneys, up to 20 m high, consist of tall spires partly stained by Fe-oxides. They are located along major faults and were formed sub-aqueously when the area was occupied by a lake. Hydrothermal carbonate structures were also found in the same area. The oxygen (δ18O) and carbon (δ13C) isotopic compositions of the chimneys range from −4.5 to 25.3‰ and from −9.44 to 8.92‰, respectively, indicating mixing between magmatic and surficial waters. Their radiogenic Sr isotopic compositions (87Sr/86Sr = 0.7049–0.7056) show values typical of altered basaltic rocks. Chimneys also exhibit negative Ce anomaly suggestive of a genetic link with basalt alteration. Overall, this study suggests that lake water chemistry in the Allols area experienced major changes in the past, reflecting various contributions of mixing fluids (lake water and hydrothermal fluids), leading alternatively to deposition of carbonate chimneys and precipitation of (and/or replacement with) silica. Schematic model of the studied area, which shows the relation between the Sakallol basins hydrothermal precipitation, groundwater and seawater from the Ghoubbet al-Kharab (Not at scale). [Display omitted] • Hydrothermal chimneys ahead of the Asal propagating rift, SE Afar Rift, Republic of Djibouti. • Radiogenic Sr isotopic compositions (87Sr/86Sr) range from 0.7049 to 0.7056 • δ18O and δ13C values of the chimneys range from −4.5 to 25.3‰ and from −9.44 to 8.92‰. • Negative Ce anomaly indicate basaltic alteration. • Mixing fluids allowed the deposition of carbonate chimneys and precipitation of (and/or replacement with) silica. [ABSTRACT FROM AUTHOR]

Differential or field asymmetric waveform ion mobility spectrometry (FAIMS) operating at high electric fields fully resolves isotopic isomers for a peptide with labeled residues. The naturally present isotopes, alone and together with targeted labels, also cause spectral shifts that approximately add for multiple heavy atoms. Separation qualitatively depends on the gas composition. These findings may enable novel strategies in proteomic and metabolomic analyses using stable isotope labeling. [ABSTRACT FROM AUTHOR]

Background and aims: Foliar water uptake has been reported for different species, including conifers living in drought-prone environments. We conducted three experiments to determine whether leaves might absorb mist water and how this affects the water relations of well-watered and water-stressed young plants of Araucaria angustifolia. Methods: Three independent experiments were conducted using well-watered and water-stressed plants: immersion of shoot in water for the quantification of water uptake, the short-term exposure of plants to deuterium-enriched artificial mist, followed by the evaluation of plant water status and δH of xylem and soil water, and the use of the heat ratio method to measure the sap flow in saplings submitted to artificial mist. Results: Foliar water uptake was demonstrated in both groups of plants, but only water-stressed plants showed a significant improvement of shoot water status. Isotope analyses indicated release of mist water in water-stressed plants rhizosphere's, and measurements of sap flow pointed to flow reversals in saplings exposed to mist, after a soil drought period. Conclusions: The results confirm the capacity of A. angustifolia for absorbing water deposited in its leaves and demonstrate that leaf-absorbed water can be transported through the xylem to the soil close to the roots and improve plant water status. [ABSTRACT FROM AUTHOR]

Zusammenfassung: Das Grab aus Kruszyn, 2009 in Kujawien entdeckt, rechnet zu einer kleinen Regionalgruppe der Schnurkeramik. Es zeichnet sich durch einen verhältnismäßig guten Erhaltungszustand und untypisch zahlreiche, aus Knochen und Geweih gefertigte Werkzeugbeigaben aus. Die aufgedeckten sterblichen Überreste wurden anthropologisch und isotopisch analysiert (14C, δ13C, δ15N, 87Sr/86Sr, δ18O), organische Reste archäozoologisch und trassologisch untersucht wie auch Sedimentproben aus dem Umfeld der Bestattung studiert. Der Befund datiert in die 2. Hälfte des 3. Jahrtausends v. Chr. und weist im Hinblick auf seine Grabkonstruktion Ähnlichkeiten mit mitteleuropäischen, frühen schnurkeramischen Hügelgräbern auf. Bestattet wurde hier ein älterer Mann nicht einheimischer Herkunft, der sich zu Lebzeiten wahrscheinlich mit der Verarbeitung von Leder beschäftigt hatte, wovon Spuren an ihm beigegebenen Werkzeugen aus Wildtierknochen zeugen. Im Grab konnten außerdem Rinderknochen und ein für spätneolithische Siedlungen jener Kultur typisches Gefäß entdeckt werden. Résumé: La tombe de Kruszyn, découverte en 2009 dans la région de Cujavie, fait partie d'un petit groupe régional de la culture à céramique cordée. Elle est relativement bien conservée et se distingue par un riche assemblage d'outils, fabriqués en os et en cornes. Des analyses anthropologiques et des investigations isotope (14C, δ13C, δ15N, 87Sr/86Sr, δ18O) ont été menées sur les débris humains, les vestiges en matières organiques ont été examinés en appliquant les méthodes archéozoologiques et l'analyse fonctionnelle. On a aussi analysé les échantillons des sédiments de l'entourage de la tombe. La tombe date de la première moitié du IIIe millénaire av. J.-C. Pour ce qui est de sa construction, elle ressemble le plus aux tumuli d'Europe centrale du début de la culture à céramique cordée. Cette sépulture appartenait à un homme âgé qui n'était pas originaire de la Cujavie et qui, probablement, travaillait le cuir: les traces laissées sur les outils en os retrouvés auprès de lui en constituent la preuve. Ils ont été fabriqués avec des matières d'origine animale sauvage. Dans la tombe, on a aussi découvert des os de vache ainsi qu'une marmite typique pour les sites de peuplement du Néolithique final. Abstract: Excavated in 2009, the barrow from Kruszyn (the Kujawy region) is related to a small regional group of the Corded Ware culture. Noteworthy is a fairly good state of its preservation and a remarkably numerous assemblage of tools made of bone and antler. Unearthed human remains were anthropologically studied and examined isotopically (14C, δ13C, δ15N, 87Sr/86Sr, δ18O), while artefacts made of organic material were subject to archaeozoological and use wear analyses. Samples of sediments surrounding the grave were also investigated. The grave dates back to the first half of the third millennium BC and in terms of its construction bears the closest resemblance to the Central European early Corded Ware barrows. It was a burial of a non-local elderly man, probably engaged in hide working in life, as evidenced by traces on the tools deposited with him in the grave and made from bones of wild animals. The grave yielded also cow bones and a pot typical for the late Neolithic settlement sites. Grób z Kruszyna, odkryty w 2009 r. na Kujawach, należy do niewielkiej regionalnej grupy kultury ceramiki sznurowej. Wyróżnia się on stosunkowo dobrym stanem zachowania oraz nietypowo licznym zbiorem narzędzi wykonanych z kości i poroża. Szczątki ludzkie poddano analizom antropologicznym i izotopowym (14C, δ13C, δ15N, 87Sr/86Sr, δ18O), dla zabytków z surowców organicznych wykonano badania archeozoologiczne i traseologiczne, przebadano również próbki osadów z otoczenia grobu. Grób pochodzi z 1. poł. 3 tys. przed Chr. i pod względem konstrukcyjnym wykazuje najbliższe podobieństwo do środkowoeuropejskich kurhanów wczesnosznurowych. Pochówek należał do starszego mężczyzny, pochodzącego spoza Kujaw, który najprawdopodobniej zajmował się obróbką skór, o czym świadczą ślady na znalezionych przy nim narzędziach. Wykonano je z surowców pochodzących od zwierząt dzikich. W grobie odkryto również kości krowy oraz garnek typowy dla późnoneolitycznych stanowisk osadowych. [ABSTRACT FROM AUTHOR]

According to environmental-based theories on the maintenance of sexual reproduction, sexual and asexual populations may coexist if they occupy different ecological niches. The aphid Rhopalosiphum padi offers a good opportunity to test this hypothesis since sexual and asexual lineages show local coexistence during a large part of their respective life-cycles. Because these two reproductive variants are morphologically identical but genetically distinct, we first characterized them using genetic markers in populations of R. padi in areas where sexual and asexual lineages may occur in sympatry. We then inferred the natal host plant of sexual and asexual genotypes by analysing stable isotopic ratios and showed that sexual ones mostly originated from C Poaceae while asexual ones originated from C and C plants, although the majority came from C Poaceae. These findings indicate that ecological niches of sexual and asexual lineages of R. padi differ, offering a plausible explanation for the local coexistence of the two reproductive modes in this species through habitat specialisation. [ABSTRACT FROM AUTHOR]

This paper explores the nature, source and spatial variation of the salinity of water used for irrigation in a coastal urban farming area in Cape Town, South Africa, where water from the Cape Flats aquifer is drawn into storage ponds and used for crop irrigation. Water samples were collected in summer and winter from selected sites across the study area and were analysed for salinity as well as for concentrations of major and minor ions. Each site consists of one borehole and one pond. Isotope analysis was done for the summer samples so as to assess effects of evaporation on water quality and salinity. Descriptive statistics were used to compare the variation in range of concentration of specific ions with the recommended ranges set by the South African Department of Water Affairs and Forestry (DWAF) and the Food and Agriculture Organisation (FAO). Geographical information system (GIS) analysis was used to describe the spatial distribution of salinity across the study area, and hydro-geochemical analysis was used to assess the possibility of seawater intrusion into the aquifer system and to characterise groundwater in the study area. The results of the research showed that the concentrations of chloride, nitrate, potassium and sodium exceeded the target maximum limit according to DWAF and FAO guidelines. Groundwater and pond water were also observed to be brackish in most parts of the research area in terms of total dissolved salts content, and fresh water was only found in the middle section of the research area. It is concluded that the accumulation of salts in groundwater and soil in the study area is mainly due to the agricultural activities and partially due to the natural movement of water through the geological formation of the Cape Flats region. These findings permit the formulation of a conceptual model of the occurrence of the salinization process, which implies that the groundwater and pond water in the study area are generally suitable for irrigation purposes, but need to be used with caution as the vegetables grown are classified as sensitive and moderately sensitive to salt according to DWAF guidelines for irrigation water quality (1996). The research paves a way for possible quantitative simulation of salt mass balance in future. [ABSTRACT FROM AUTHOR]

This literature review focuses on the prevalence of nitrogen and phosphorus in urban environments and the complex relationships between land use and water quality. Extensive research in urban watersheds has broadened our knowledge about point and non-point pollutant sources, but the fate of nutrients is not completely understood. For example, it is not known how long-term nutrient cycling processes in turfgrass landscapes influence nitrogen retention rates or the relative atmospheric contribution to urban nitrogen exports. The effect of prolonged reclaimed water irrigation is also unknown. Stable isotopes have been used to trace pollutants, but distinguishing sources (e.g., fertilizers, wastewater, etc.) can be difficult. Identifying pollutant sources may aid our understanding of harmful algal blooms because the extent of the relationship between urban nutrient sources and algal blooms is unclear. Further research on the delivery and fate of nutrients within urban watersheds is needed to address manageable water quality impacts. [Copyright &y& Elsevier]

A variety of unique radioactive samples have been measured recently at Los Alamos National Laboratory (LANL) using an electrically-cooled high-purity germanium detector. In each case the purpose of the measurements included one or more of the following objectives: (1) an accurate determination of the isotopic weight fractions of different plutonium or uranium materials; (2) an accurate determination of the isotopic quantity in the absence of relevant calibration standards; and (3) a qualitative determination of various sample impurities for additional forensic information. This paper discusses how simple modifications to the PC-FRAM parameter sets enabled a better determination of the isotopic content of the following samples: (1) high-purity plutonium metal, (2) plutonium-beryllium (PuBe) neutron sources, (3) neutron-irradiated natural uranium, and (4) re-processed HEU fuel with elevated 236U content. The isotopic quantity in a variety of samples was determined using a combination of the Spectral Nondestructive Assay Platform (SNAP™) routine from Eberline Services and the Monte Carlo Neutral Particle (MCNP) code developed at LANL. The non-traditional sources that were quantified with these gamma ray modeling codes included dozens of neutron-irradiated targets of natural uranium, several plutonium-beryllium neutron sources, and three high-purity samples of plutonium metal. [ABSTRACT FROM AUTHOR]

Abstract: Honey samples were analyzed by stable carbon isotopic ratio analysis by mass spectrometry (SCIRA-MS) and site-specific natural isotopic fractionation measured by nuclear magnetic resonance (SNIF-NMR) to first determine their potentials for characterizing the substance and then to combat adulteration. Honey samples from several geographic and botanical origins were analyzed. The δ 13C parameter was not significant for characterizing an origin, while the (D/H)I ratio could be used to differentiate certain single-flower varieties. Application of the official control method of adding a C4 syrup (AOAC official method 998.12) to our authentic samples revealed anomalies resulting from SCIRA indices that were more negative than −1‰ (permil). A filtration step was added to the experimental procedure and provided results that were compliant with the natural origin of our honey samples. In addition, spiking with a C4 syrup could be detected starting at 9–10%. The use of SNIF-NMR is limited by the detection of a syrup spike starting only at 20%, which is far from satisfying. [Copyright &y& Elsevier]

This study deals with the chemical characterization of the biogeochemical processes occurring in a shallow aquifer in crystalline rocks. The influence of rock heterogeneity and the related physical processes on the aquifer biogeochemistry have been investigated. A hydrochemical survey (major anion and cation analysis) shows that rock heterogeneity leads to a stronger spatial than temporal variability. Some rapidly recharged and low- mineralized waters are present at the soil/rock interface. However the pumped well intersects a preferential flow path and pumps nitrate-rich water. Sulfur and oxygen isotope data from sulfates in the pumped water clearly show sulfide oxidation with only 20–30% of the oxygen atoms in sulfates formed by sulfide oxidation coming from atmospheric oxygen. This low contribution of molecular oxygen in sulfide oxidation, associated with the drastic decrease in nitrate concentration, involves a marked relationship between the nitrogen and sulfur cycles through denitrification, coupled with sulfide oxidation. Conversely, for rapidly recharged waters, the rock physical heterogeneity allows sulfide oxidation by molecular oxygen indicated by a contribution of atmospheric oxygen of nearly 70% in the newly formed sulfate. As the aquifer biogeochemistry is controlled by the physical characteristics of the rocks, pumping may overcome the natural flux pattern described previously. This anthropogenic disturbance leads to a modification of water pathways (spatial mixing or relative contribution of the fracture/matrix waters to the global fluxes) and, consequently, to a modification of the physical and biogeochemical processes occurring in the aquifer. [ABSTRACT FROM AUTHOR]

In otherwise nutrient-poor savannas, fertile vegetation patches are particularly attractive to ungulates because of the higher-quality food they provide. We investigated forage plants and diet of the common warthog (Phacochoerus africanus) on an abandoned cattle ranch in coastal Tanzania. The forage grasses of highest nutritional quality occurred in former paddock enclosures (bomas) where cattle had been herded at night. In the dry season, grass samples from bomas contained approximately 4 times as much nitrogen and phosphorus as those of the surrounding vegetation. δ15N values of soil and plants also were highest in bomas and decreased significantly with distance, and high δ15N values in feces suggest that warthogs preferentially fed in the vicinity of the former bomas. δ13C values of warthog feces indicate that warthogs ingested on average 83% (77-98%) C4 grasses, with this proportion varying regionally but not seasonally. We conclude that, for medium-sized selective grazers such as warthogs, bomas represent attractive feeding grounds. We also hypothesize that by promoting nutrient turnover in these patchily distributed areas, grazing animals help to maintain them as sources of high-quality forage. [ABSTRACT FROM AUTHOR]

Reported is a comparative study of the nuclear magnetic resonance (NMR) spectrometric measurement of 6Li with the Knudsen effusion high temperature mass spectrometry (HTMS) determination of 6Li and 7Li. A limit of detection of 0.002–0.007 at.% for 6Li was achieved by NMR with the use of calibrated standard reference materials. This study has shown that 6Li NMR is effective, rapid, and a nondestructive analytical technique for the accurate isotopic analysis of Li salts enriched in 7Li up to 99.95 at.%. The relative standard deviation (RSD) for NMR 6Li determinations in highly enriched Li salts was 0.002–0.007 at.%, when the 6Li content was in the range of 0.05–0.10 at.%. Effusion Knudsen HTMS measurements of samples of various isotopic compositions of highly enriched 7Li lithium salts were completed using mass peaks of Li2Cl+ (m/z=47–51 u). The limit of detection achieved for 6Li in enriched 7Li salts was 0.0002–0.0005 at.% measured with a RSD of 0.015–0.080 at.%. Effusion Knudsen HTMS is an absolute method of analysis requiring no calibration standards. [Copyright &y& Elsevier]

Presents a workshops on isotopic analyses for carbon cycle in the U.S. Theme of the conventions; Participants; Venue.