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The global biosphere is commonly assumed to have been less productive before the rise of complex eukaryotic ecosystems than it is today 1 . However, direct evidence for this assertion is lacking. Here we present triple oxygen isotope measurements (∆ 17 O) from sedimentary sulfates from the Sibley basin (Ontario, Canada) dated to about 1.4 billion years ago, which provide evidence for a less productive biosphere in the middle of the Proterozoic eon. We report what are, to our knowledge, the most-negative ∆ 17 O values (down to −0.88‰) observed in sulfates, except for those from the terminal Cryogenian period 2 . This observation demonstrates that the mid-Proterozoic atmosphere was distinct from what persisted over approximately the past 0.5 billion years, directly reflecting a unique interplay among the atmospheric partial pressures of CO 2 and O 2 and the photosynthetic O 2 flux at this time 3 . Oxygenic gross primary productivity is stoichiometrically related to the photosynthetic O 2 flux to the atmosphere. Under current estimates of mid-Proterozoic atmospheric partial pressure of CO 2 (2–30 times that of pre-anthropogenic levels), our modelling indicates that gross primary productivity was between about 6% and 41% of pre-anthropogenic levels if atmospheric O 2 was between 0.1–1% or 1–10% of pre-anthropogenic levels, respectively. When compared to estimates of Archaean 4 – 6 and Phanerozoic primary production 7 , these model solutions show that an increasingly more productive biosphere accompanied the broad secular pattern of increasing atmospheric O 2 over geologic time 8 . Triple oxygen isotope measurements of 1.4-billion-year-old sedimentary sulfates reveal a unique mid-Proterozoic atmosphere and demonstrate that gross primary productivity in the mid-Proterozoic was between 6% and 41% of pre-anthropogenic levels.

Significant efforts have been made in recent years to produce healthier wines, with the primary goal of reducing the use of sulfur dioxide (SO2), which poses health risks. This study aimed to assess the effectiveness of three plant-derived polyphenols (dihydromyricetin, resveratrol, and catechins) as alternatives to SO2 in wine. After a three-month aging process, the wines were evaluated using analytical techniques such as high-performance liquid chromatography, colorimetry, gas chromatography–olfactometry–mass spectrometry, as well as electronic nose and electronic tongue analyses, with the purpose to assess parameters including antioxidant activity, color, contents of volatile aroma compounds, and sensory characteristics. The results demonstrated various degrees of improvement in the antioxidant activity, aromatic intensity, and sensory characteristics of wines using polyphenols. Notably, dihydromyricetin (200 mg/L) exhibited the strongest antioxidant activity, with increases of 18.84%, 23.28%, and 20.87% in 2,2-diphenyl-1-picrylhydrazyl, 2,2’azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and ferric-ion-reducing antioxidant power assays, respectively. Resveratrol (200 mg/L) made the most significant contribution to volatile aroma compounds, with an 8.89% increase in the total content of alcohol esters. In E-nose analysis, catechins (200 mg/L) showed the highest response to aromatic compounds and the lowest response to volatile sulfur compounds, while also exhibiting the best sensory characteristics. Therefore, the three plant-derived polyphenols investigated here exhibited the potential to enhance wine quality as alternatives to SO2. However, it is important to consider the specific impact of different polyphenols on wine; hence, suitable antioxidants should be selected in wine production according to specific requirements.

Population movements constitute a significant driver of cultural change in prehistoric societies. In recent years, sulfur isotopes have emerged as a valuable approach for distinguishing human/animal provenance. However, the scarcity of sulfur isotope studies and the lack of baseline maps predicting their variations in the landscape limit our current knowledge about mobility behaviours. Here, we first present the δ 34 S isotope values of 142 human and animal bone collagen samples from coastal and inland funerary sites located in northern Iberia. Second, to apply a multivariate machine-learning regression and a random forest model to predict sulfur isotope variations across Iberia, we compiled the sulfur isotope data from 554 specimens of 41 archaeological locations from Holocene contexts. Our research demonstrated that population movement between coastal and inland locations is observable through differences in the δ 34 S isotope values of individuals linked to their respective environments, suggesting migrations on both sides of the Cantabrian mountain range. The resulting isoscape model demonstrates that sulfur isotope patterns are highly predictable, with 82% of the sulfur isotope variation explained by only four variables: elevation, Bouguer anomaly, distance from the coast, and strontium isotope values. While the model is highly accurate for regions with large amounts of data, such as northern Iberia, Central and Eastern Iberia still require more sulfur isotope data to predict isoscapes.

The Chicxulub asteroid impact event at the Cretaceous-Paleogene (K-Pg) boundary ~66 Myr ago is widely considered responsible for the mass extinction event leading to the demise of the non-avian dinosaurs. Short-term cooling due to massive release of climate-active agents is hypothesized to have been crucial, with S-bearing gases originating from the target rock vaporization considered an important driving force. Yet, the magnitude of the S release remains poorly constrained. Here we empirically estimate the amount of impact-released S relying on the concentration of S and its isotopic composition within the impact structure and a set of terrestrial K-Pg boundary ejecta sites. The average value of 67 ± 39 Gt obtained is ~5-fold lower than previous numerical estimates. The lower mass of S-released may indicate a less prominent role for S emission leading to a milder impact winter with key implications for species survival during the first years following the impact. The amount of S released by the Chicxulub impact event is empirically determined to be 5 times lower than previously estimated, with important consequences for our understanding of the climate cooling that ultimately led to the K-Pg mass extinction.

Sulphur dioxide and atmospheric oxygenation Around two and a half billion years ago (following the end of the Archaean eon), the atmosphere turned from anoxic to weakly oxic in what is known as the Great Oxidation Event. Using a model of volcanic degassing, Gaillard et al . demonstrate that a preceding period of continental crust formation may have been the trigger. They propose that as continents emerged and volcanoes became increasingly subaerial rather than submarine, magmatic volatiles were degassed at lower pressures, leading to a progressive oxidation of the gases released. This shift to a release of sulphur as sulphur dioxide rather than as hydrogen sulphide could then have fed marine sulphate reduction and the eventual oxygenation of Earth's atmosphere. The Precambrian history of our planet is marked by two major events: a pulse of continental crust formation at the end of the Archaean eon and a weak oxygenation of the atmosphere (the Great Oxidation Event) that followed, at 2.45 billion years ago. This oxygenation has been linked to the emergence of oxygenic cyanobacteria 1 , 2 and to changes in the compositions of volcanic gases 3 , 4 , but not to the composition of erupting lavas—geochemical constraints indicate that the oxidation state of basalts and their mantle sources has remained constant since 3.5 billion years ago 5 , 6 . Here we propose that a decrease in the average pressure of volcanic degassing changed the oxidation state of sulphur in volcanic gases, initiating the modern biogeochemical sulphur cycle and triggering atmospheric oxygenation. Using thermodynamic calculations simulating gas–melt equilibria in erupting magmas, we suggest that mostly submarine Archaean volcanoes produced gases with SO 2 /H 2 S < 1 and low sulphur content. Emergence of the continents due to a global decrease in sea level and growth of the continental crust in the late Archaean then led to widespread subaerial volcanism, which in turn yielded gases much richer in sulphur and dominated by SO 2 . Dissolution of sulphur in sea water and the onset of sulphate reduction processes could then oxidize the atmosphere.

Six new sesquiterpene coumarin ethers, namely turcicanol A (1), turcicanol A acetate (2), turcicanol B (3), turcica ketone (4), 11′-dehydrokaratavicinol (5), and galbanaldehyde (6), and one new sulfur-containing compound, namely turcicasulphide (7), along with thirty-two known secondary metabolites were isolated from the root of the endemic species Ferula turcica Akalın, Miski, & Tuncay through a bioassay-guided isolation approach. The structures of the new compounds were elucidated by spectroscopic analysis and comparison with the literature. Cell growth inhibition of colon cancer cell lines (COLO205 and HCT116) and kidney cancer cell lines (UO31 and A498) was used to guide isolation. Seventeen of the compounds showed significant activity against the cell lines.

High-resolution chemostratigraphy reveals an episode of enrichment of the redox-sensitive transition metals molybdenum and rhenium in the late Archean Mount McRae Shale in Western Australia. Correlations with organic carbon indicate that these metals were derived from contemporaneous seawater. Rhenium/osmium geochronology demonstrates that the enrichment is a primary sedimentary feature dating to 2501 ± 8 million years ago (Ma). Molybdenum and rhenium were probably supplied to Archean oceans by oxidative weathering of crustal sulfide minerals. These findings point to the presence of small amounts of O₂ in the environment more than 50 million years before the start of the Great Oxidation Event.

The objective of this study was to investigate the use of the acid production potential (AP) calculation factor and seven different S analysis methods in the preliminary mine waste characterization by analyzing and comparing 48 Finnish mine waste samples. Special attention was paid on mineralogical aspects and data produced in the exploration phase of a mining project. According to our results, the abundance of sulfide species other than pyrite in Finnish mine waste suggests that the factor to calculate the AP should be considered based on mineralogy and would often be below 31.25. Therefore, the mineralogy-based determination of S should be preferred. However, the determination of S based on scanning electron microscope (SEM) mineralogy includes some uncertainties. Underestimation of S content may appear if not all S-bearing mineral particles have been detected, or if the amount of S is low in general. This uncertainty appears to be especially related to the samples containing elevated (> 9 wt%) amounts of serpentine, diopside, augite, and/or hornblende. Risk of overestimating AP is related to samples containing high amounts (> 4.13 wt%) of S-bearing minerals. These uncertainties can be reduced by inspecting that the SEM mineralogy-based S concentrations are in line with the energy dispersive X-ray spectrometer data. The aqua regia extractable S concentrations, which are often available in the exploration phase, appeared to be usable in the preliminary waste rock AP assessment and often comparable with the analytical total S values in the Finnish waste rock samples, especially when the samples did not contain any sulfate minerals. In contrast, the analytical sulfide S and the X-ray fluorescence methods may lead to an underestimation of AP.

Volatile sulfur compounds (VSCs) are key odorous compounds from emissions of various odour sources because they are odorous and generally have very low odour threshold values. Identification and quantification of them through air server–thermal desorber–gas chromatography–sulfur chemiluminescence detector (AS-TD-GC-SCD) become more and more popular, although VSCs can be determined by other detectors. To find a valid, practical and quick calibration method is also an important step in their analytical processes. This study compared three different sample preparation and unity sampling methods using both gas standards (with 10 VSCs balanced in pure nitrogen gas) and liquid standards of 7 VSCs. For liquid standard sample preparation, two solvents (methanol and n-pentane) were tested and their calibration results were compared. The study revealed that the three calibration methods with both manual and dynamic dilution of VSC standard gases can achieve satisfactory calibration results with nice linear regression and correlation coefficient ( r 2 ). The dynamic dilution and loop sampling method is recommended because of its better reliability and time-saving processing. For calibration of VSCs with liquid standards, preparing the samples using dissolved VSCs in n-pentane and analysing them using the loop sampling method achieved best calibration results. For dimethyl trisulfide (DMTS), its calibration cannot obtain as good results as other sulfur compounds even using the best performance calibration method.

Microscopic sulfides with low ³⁴S/³²S ratios in marine sulfate deposits from the 3490-million-yearold Dresser Formation, Australia, have been interpreted as evidence for the presence of early sulfate-reducing organisms on Earth. We show that these microscopic sulfides have a mass-independently fractionated sulfur isotopic anomaly (Δ³³S) that differs from that of their host sulfate (barite). These microscopic sulfides could not have been produced by sulfate-reducing microbes, nor by abiologic processes that involve reduction of sulfate. Instead, we interpret the combined negative δ³⁴S and positive Δ³³S signature of these microscopic sulfides as evidence for the early existence of organisms that disproportionate elemental sulfur.