Substantial Concentrations Research Articles

Measurement report: The ice-nucleating activity of lichen sampled in a northern European boreal forest

Abstract. Ice-nucleating particles (INPs) facilitate the heterogeneous freezing of cloud droplets and thus modify cloud properties. Hence, it is important to understand the sources of INPs. During the HyICE-2018 campaign, which took place in the boreal forest of Hyytiälä, substantial concentrations of airborne heat-sensitive biological INPs were observed, despite many potential biological sources of INPs being snow-covered. A potential source of INPs that were not covered in snow was lichens that grow on trees; hence, we investigated these lichens as a potential source of biological INPs in this boreal forest environment. INPs derived from lichen sampled during HyICE-2018 are shown to nucleate ice at temperatures as warm as −5 °C with 103 INPs per gram of lichen. Successive filtration to smaller sizes removes some of the most active INPs in suspension, but substantial activity remains, even when filtering to 0.1 µm. The small size of the INPs from lichen means they have the potential to either be emitted directly into the atmosphere or be associated with larger particles, such as lichenous reproductive aerosol types (spores or diaspores). We also show that the INPs from lichens from Hyytiälä are sensitive to heat, which is similar to the INPs sampled from the atmosphere of Hyytiälä and consistent with the presence of ice-active proteins. Adding to previous evidence of lichenous INPs, this study shows that lichens from a European boreal forest in Hyytiälä harbour INPs. This novel finding may be especially important in this snow-covered habitat where few, if any, other biological INP sources are available. The great terrestrial abundance of lichens in Hyytiälä, and around the world, calls for further research to combine their ice-nucleating ability with dispersal studies to evaluate the flux of lichenous INPs into the atmosphere, as well as to what extent these particles reach heights and locations where they might influence cloud properties.

Potential Air Quality Side-Effects of Emitting H2O2 to Enhance Methane Oxidation as a Climate Solution.

Methane (CH4) is a greenhouse gas with a global warming potential 81.2 times higher than carbon dioxide (CO2). The intentional emission of oxidants into the atmosphere has been proposed as a geoengineering solution to accelerate the oxidation of CH4 to CO2, thereby reducing surface warming. However, there has been little consideration for competing atmospheric oxidation pathways that will reduce CH4 oxidation efficiencies and result in the formation of secondary pollutants such as ozone and particulate matter. Using a global chemical-transport model, we simulate a proposed technology to intentionally emit H2O2 into the atmosphere to elevate OH concentrations and enhance CH4 oxidation. We find that proposed emission rates of oxidants have minimal impacts on monthly average tropospheric ozone and particulate matter concentrations. However, competition for the oxidation of CH4 would necessitate widespread adoption of such technology to remove substantial concentrations of atmospheric CH4, which would in-turn cause considerable increases in regional winter-time particulate matter. Our work underscores the need to consider competing chemistry in evaluating the efficacy and side effects of proposals to enhance the atmospheric oxidation of CH4 as a climate solution.

Assessment of heavy metals distribution and environmental risks in biochar from co-pyrolysis of sewage sludge and mixed municipal waste.

The substantial heavy metal concentrations in sewage sludge (SS) from wastewater treatment pose environmental risks and limit its practical applications. To mitigate this, SS was co-pyrolyzed with mixed municipal waste (MMW), and the heavy metals (HMs) distribution in the resulting biochar and leachate was analyzed through ICP-MS. Ecological risk (Er) and geological accumulation index (Igeo) were evaluated for various blending ratio. Results showed that MMW biochar exhibited high carbon and low sulfur content, indicating potential for carbon sequestration and soil enhancement. Both biochar showed intricate pore structures, with a slight increase in surface area, and greater aromaticity observed with the addition of MMW. Pyrolysis concentrated HMs in SS biochar, but enhanced stability reduced their leachate levels. Adding MMW decrease the level of HMs in biochar and leachate, notably reducing Se leaching from 1.54% to 0.12% and slightly lowering Hg and Cu levels. Co-pyrolysis stabilized Se by combining it with organic matter. Er analysis indicated a reduction in Hg and Cd risks by 86.6 and 41.23, respectively, with cumulative ecological risk (RI) dropping from 339.7 to 175.7. Higher MMW ratios reduced Igeo values for Zn, Cd, and Cu, shifting risks from strong to moderate and improving biochar’s agricultural suitability. High Cu and Zn levels in SS, originating from zinc and copper pipes in water treatment, were mitigated by MMW blending. Hence, the optimal co-pyrolysis ratio for HMs immobilization and SS disposal is 50% MMW. These results emphasize the importance of co-pyrolysis to produce safe biochar with reduced ecological risks. However, further research is required to optimize co-pyrolysis for various sludge types at higher pyrolysis temperatures (beyond 400℃) with the application of acid leaching agents.

Organic alkalinity distributions, characteristics, and application to carbonate system calculations in estuarine and coastal systems

AbstractThe capacity of aquatic systems to buffer acidification depends on the sum contributions of various chemical species to total alkalinity (TA). Major TA contributors are inorganic, with carbonate and bicarbonate considered the most important. However, growing evidence shows that many rivers, estuaries, and coastal waters contain dissolved organic molecules with charge sites that create organic alkalinity (OrgAlk). This study describes the first comparison of (1) OrgAlk distributions and (2) acid–base properties in contrasting estuary‐plume systems: the Pleasant (Maine, USA) and the St. John (New Brunswick, CA). The substantial concentrations of OrgAlk in each estuary were sometimes not conservative with salinity and typically associated with very low pH. Two approaches to OrgAlk measurement showed consistent differences, indicating acid–base characteristics inconsistent with the TA definition. The OrgAlk fraction of TA ranged from 78% at low salinity to less than 0.4% in the coastal ocean endmember. Modeling of titration data identified three groups of organic charge sites, with mean acid–base dissociation constants (pKa) of 4.2 (± 0.5), 5.9 (± 0.7) and 8.5 (± 0.2). These represented 21% (± 9%), 8% (± 5%), and 71% (± 11%) of titrated organic charge groups. Including OrgAlk, pKa, and titrated organic charge groups in carbonate system calculations improved estimates of pH. However, low and medium salinity, organic‐rich samples demonstrated persistent offsets in calculated pH, even using dissolved inorganic carbon and CO2 partial pressure as inputs. These offsets show the ongoing challenge of carbonate system intercomparisons in organic rich systems whereby new techniques and further investigations are needed to fully account for OrgAlk in TA titrations.

Natural cross-reactive anti-SARS-CoV-2 antibodies in avian egg yolk.

Since the beginning of the 21st century, the Coronaviridiae family has caused several life-threatening outbreaks in the world. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the cause of the latest Coronaviridiae-related outbreak, is still a major health issue worldwide. Prevention, diagnosis, and therapeutic actions are the most important strategies to mitigate the spread of the COVID-19 pandemic. Among therapeutics, specific antibodies play a crucial role in controlling the symptoms of patients and preventing others from becoming infected. Here, we have introduced the avian egg yolk as a natural source of cross-reactive anti-SARS-CoV-2 immunoglobulin Y. ELISA, dot blot and western blot were used to identify natural anti-SARS-CoV-2 IgY in the egg yolk of different species of birds. Also, bioinformatics analysis was performed to investigate the possible causes of the presence of these natural antibodies in the egg yolks. The results of blotting and ELISA assays demonstrated that the egg yolk-derived antibodies could identify and bind to the different subunits of SARS-CoV-2. Substantial concentrations of neutralizing antibodies against SARS-CoV-2 were also detected in the egg yolk. In addition, bioinformatics analysis showed structural similarities between the components of infectious bronchitis virus, SARS-CoV-2, and other members of the Coronaviridiae family. It seems that egg yolk can be used as a natural, inexpensive, and accessible source of anti-SARS-CoV-2 antibodies. Diverse diagnostic and therapeutic potentials for avian egg yolk-derived anti-SARS-CoV-2 antibodies are imagined.

An attempt to determine the cause of the strong tremor responsible for a rockburst in a hard coal mine based on numerical modeling and spectral parameter

Seismic and rockburst hazards represent significant challenges during the longwall mining of coal seams. One analytical approach to assess the potential for rockburst hazards involves reconstructing the stress conditions within the rock mass. This article reports on the findings from three-dimensional (3D) numerical modeling aimed at examining the distribution of maximum shear stress within the rock mass amid the longwall mining operations of the 703/1 coal seam in a mine situated in the Upper Silesian Coal Basin, Poland which was disrupted by a rockburst incident. On the day of the rockburst, substantial concentrations of maximum shear stress were identified in a thick sandstone layer proximate to the boundary of the overlying 624 coal seam located significantly above the 703/1 coal seam. The calculated maximum shear stress demonstrated an increase of approximately 80% over the values observed in the absence of edge effects. Furthermore, a higher concentration of maximum shear stress was identified within the geologically weaker strata adjacent to the 703/1 coal seam. These observations facilitated the classification of the examined rockburst as a stress-stroke phenomenon. Additionally, the study determined the spectral parameters of the tremor, which possessed an energy of 9.8 × 107 J and triggered the analyzed rockburst. The ratio of the seismic energy of S and P-waves confirmed a shear mechanism in the focus. The scope of inelastic deformation within the focal zone was also quantified. Following the event, the rock mass that had been destressed due to the significant tremor and subsequent rockburst exhibited reduced seismic activity upon the resumption of longwall mining of the 703/1 coal seam.

Terrapower’s Molten Chloride Fast Reactor (MCFR): Advancements in Electrochemical Monitoring and Control

TerraPower’s Molten Chloride Fast Reactor (MCFR) project is pioneering a nuclear reactor technology that leverages fast spectrum chloride as a fuel salt and chloride salts as coolant salts, offering vast potential for decarbonizing various economic sectors. The fast spectrum enhances the neutron economy, mitigating fission product poisoning. Utilizing a NaCl-UCl3 binary eutectic as the fuel salt, the reactor undergoes significant chemical transformations during burn-up. The resulting species from the fission process, including Kr(0), Xe(0), Rb(I), Cs(I), Sr(II), Ba(II), Zr(II), Nb(0), Mo(0), Te(0), I(0), Pd(II), Re(I), Rh(II), Ag(I), Cd(II), rare earths(III), are in oxidation states equal to or lower than the initial U(III). This transformation leads to an oxidizing melt, potentially converting U(III) to U(IV), which can trigger oxidative corrosion of the structural materials.To address these challenges, TerraPower is employing diverse electrochemical and electroanalytical approaches for process monitoring and control, helping bridge existing knowledge gaps in fuel and coolant salts. These methods provide key insights into species thermodynamics and kinetics, enabling direct measurement of redox information crucial for the operation of a molten salt nuclear reactor. This presentation will discuss TerraPower’s efforts in applying diverse electrochemical and electroanalytical approaches towards process monitoring and process control, addressing the knowledge gaps that exist for both fuel and coolant salts.Basic electrochemical experiments on initial fuel salt provide data for models that predict and prevent corrosion, identify species affecting reactor physics, and offer real-time monitoring of the need to remove fission product poisons. Spectroelectrochemical methods are adapted to examine how redox transformations impact the coordination and speciation of uranium complexes in the fuel, crucial for predicting precipitation and volatilization of U(IV) species. This presentation will discuss TeraPower’s progress in electrochemical and spectroelectrochemical experiments.TerraPower has designed two novel electrochemical and spectroelectrochemical cells that serve as testbeds for understanding fundamental redox chemistry and developing probes for process monitoring. For instance, measuring salt potential relative to the ratio of uranium oxidation states enables monitoring the U(III):U(IV) ratio, crucial for maintaining an optimal reactor environment. The temperature dependency of this value will also be characterized, providing a reference for system perturbations.The presentation will also touch upon the influence of fission and corrosion products on the equilibrium behavior of uranium throughout the fuel's operational life. Fission products may reach substantial concentrations in the salt, imposing varied redox conditions that drive different behaviors in uranium. The dependence of uranium oxidation state ratio on burnup will be evaluated, and method development will explore the relationship between chlorine potential and species solubility.Through this comprehensive approach, TerraPower aims to advance the MCFR technology, ensuring safe and efficient nuclear energy generation with significant benefits for decarbonizing the economy.

UPLC-MS/MS-based metabolomics combined to chemometrics reveal the anti-inflammatory metabolites of African Marigold (Tagetes erecta L.) flowers

African Marigold (Tagetes erecta L.) is widely recognized for its ornamental value and therapeutic properties, particularly its anti-inflammatory potential. This study employs UPLC-MS/MS-based metabolomics combined with chemometric analysis to identify bioactive metabolites contributing to the anti-inflammatory effects of T. erecta flowers. The flowers were fractionated using hexane, methylene chloride, ethyl acetate, and butanol, and a total of 79 metabolites were identified across the fractions, including flavonoids, phenolic acids, tannins, quinic acids, terpenoids, alkaloids, and amino acids. The anti-inflammatory efficacy of each fraction was assessed in vitro by evaluating their impact on the expression of four pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, and IFN-γ) in LPS-stimulated leukocytes using PCR. Orthogonal Projections to Latent Structures was employed to determine the key metabolites contributing to the observed bioactivity. The analysis revealed that the methylene chloride and ethyl acetate fractions exhibited the most potent anti-inflammatory effects, primarily due to the presence of flavonoids and phenolic acids. Notably, disyringic acid hexoside, ellagic acid, gallic acid, p-coumaric acid, and quercetagetin dimethyl ether were identified as major anti-inflammatory agents based on their high correlation coefficients with cytokine inhibition and their substantial concentrations within the active fractions. These findings underscore the importance of selecting appropriate extraction solvents to isolate specific bioactive compounds and provide a deeper understanding of the metabolite profiles that contribute to the anti-inflammatory properties of T. erecta flowers.

Organoenergetic Investigation on the Potential of Industrial Brewers' Spent Grain Valorization for Biogas Production

Cameroon is a high country producer and consumer of beer in Africa which has various breweries generating a large amount of brewer spent grain (BSG) yearly. This study was designed to investigate the potential use of spent grains derived from the Cameroonian brewing industry as a viable and sustainable energy source for biogas production. A comprehensive proximate analysis was performed, focusing on key physicochemical parameters including moisture content, acidity level, ash content, and the proportions of proteins, carbohydrates, and fats, thereby enabling the derivation of their energy value to determine the organoenergetic profile. Physicochemical characterization of the spent grains revealed a pH of 5.6, moisture content of 8%, and ash content of 9.8% at 450 °C for 2 h using a muffle furnace. The organic composition included a high iron content of 194.2 mg/100 g, an organic matter content of 99%, a total organic carbon (TOC) content of 57.39%, a total nitrogen content of 3%, and a nitrogen-carbon ratio of 19.13%. In addition, the spent grains exhibited substantial concentrations of total protein (18.75%), crude fiber (3.6%), lipids (8.7%), and carbohydrates (51.15%), with an energy value of 14.97 MJ/kg. Moreover, the chemical oxygen demand (COD) was determined to be 3,880 mg/kg, while the lower calorific value (LCV) was 19.76 MJ/kg, resulting in a COD/TOC ratio of 86.03. These findings showed that the spent grain from Cameroonian brewery has a significant organ energetic potential based on its components and physicochemical properties, thereby highlighting their suitability as a valuable resource for biogas generation.

Air pollution from unconventional oil and gas development in the Eagle Ford Shale

Unconventional oil and gas development (UOGD) has experienced substantial growth in recent years with currently unconstrained impacts on air quality. In this work, we describe ambient aerosol and gas-phase measurements during spring 2021 to examine air quality in the Eagle Ford Shale (EFS), a region in southeast Texas with thousands of UOGD wells. NOx, O3, H2S, PM1, and several VOCs were measured at concentrations above expected levels for non-urban regions. Hydrocarbon measurements from gas chromatography (GC) and proton transfer reaction (PTR) mass spectrometry show periodic high concentrations of variable compositions consisting of both saturated and unsaturated (polycyclic and/or aromatic) hydrocarbons, including larger (C > 10) unsaturated hydrocarbons that are often not quantified by GC measurements but are still present at substantial concentrations and relevant for air quality. Hydrocarbon VOCs are expected pollutants from anthropogenic activity and, based on ratios of i-pentane to n-pentane, xylene to benzene, and toluene to benzene, measured VOC ratios were characteristic of UOGD activity. Wind data and back-trajectory analyses show that air predominantly arrived from the S/SE, consistent with UOGD sources as well as shipping emissions from the Gulf of Mexico impacting air quality in the EFS. Analysis of diurnal trends at the site show hydrocarbon and NOx accumulation overnight and highlight diurnal differences in oxidative conditions, with important implications for both SOA and O3 formation. UOGD emissions impact the air quality in Karnes City and more broadly the EFS as well as the nearby urban area of San Antonio, which struggles to meet national air quality standards set by the Environmental Protection Agency.

Microbial adhesion on different types of orthodontic brackets and wires: An in vitro study

ObjectiveThe objective of this study was to compare the microbial adhesion of different oral pathogens on different wires used in orthodontic treatment and to evaluate the potential of these pathogens to form biofilms on different types of orthodontic wires and brackets. MethodsIn this in vitro investigation, we calculated that the sample size for each group (i.e., those with brackets [metal braces, ceramic braces, and self-ligating braces] and wires [nickel titanium, titanium molybdenum, and stainless steel]) should be 15 individuals. Five types of microbes (Streptococcus mutans, Escherichia coli, Enterococcus faecalis, Staphylococcus aureus, and Candida albicans) were used. Three types of brackets and three types of wires were used with five types of bacteria, and the process was repeated three times to collect the average. ResultsNo significant differences were observed in the mean concentrations of bacteria in the different brackets (p > 0.05) or in the mean concentrations in the different orthodontic materials used in these brackets. In contrast, there were considerable differences between the concentrations of bacteria in the wires and those in the brackets (p < 0.05). ConclusionDifferent wires and brackets have different associations with bacterial adhesion and concentration. The wires exhibited more substantial biofilm absorbance and concentrations than the brackets. The adhesion of biofilm may be a decisive factor when choosing a type of orthodontic wire, particularly for individuals at high risk of developing bacterial oral diseases, such as periodontal diseases and dental caries.

Dissolution‐Recrystallization: A Novel Mechanism for Fluorochromic Detection of Th4+ Using Color‐Tunable Luminescent Metal–Organic Frameworks

AbstractThorium, a predominant actinide in the Earth's crust, presents significant environmental and health risks due to its radioactive nature. These risks are particularly pronounced during the mining and processing of monazite for rare earth elements (REEs), which contain substantial thorium concentrations. Current instrumental analysis methods for thorium, offer high accuracy but require laborious sample preparations and expensive instruments, making them unsuitable for on‐site analysis. Herein, we present a class of color‐tunable luminescent lanthanide‐based metal–organic frameworks (Ln‐MOFs) as fluorochromic sensors for Th4+ cations. Utilizing a heterobimetallic Eu3+/Tb3+ doping strategy, the luminescence colors of EuxTb1‐x‐BDC‐OH can be finely tuned from red, to orange, and to green. More intriguingly, the higher Lewis acidity of Th4+ facilitates the transformation of EuxTb1‐x‐BDC‐OH into a UiO‐type Th‐MOF via a dissolution‐recrystallization mechanism. This process results in a gradual reduction of characteristic Ln3+ emissions and the emergence of blue color ligand‐based fluorescence, thereby leading to selective fluorochromic responses with increasing Th4+ concentrations and enabling visible detection of Th4+ cations. Additionally, a custom‐built portable optoelectronic device is fabricated, which directly converts luminescence colors into red‐green‐blue (RGB) values. This device enables easy quantification of Th4+ concentrations without the need for complex instrumentation.

Dissolution-Recrystallization: A Novel Mechanism for Fluorochromic Detection of Th4+ Using Color-Tunable Luminescent Metal-Organic Frameworks.

Thorium, a predominant actinide in the Earth's crust, presents significant environmental and health risks due to its radioactive nature. These risks are particularly pronounced during the mining and processing of monazite for rare earth elements (REEs), which contain substantial thorium concentrations. Current instrumental analysis methods for thorium, offer high accuracy but require laborious sample preparations and expensive instruments, making them unsuitable for on-site analysis. Herein, we present a class of color-tunable luminescent lanthanide-based metal-organic frameworks (Ln-MOFs) as fluorochromic sensors for Th4+ cations. Utilizing a heterobimetallic Eu3+/Tb3+ doping strategy, the luminescence colors of EuxTb1-x-BDC-OH can be finely tuned from red, to orange, and to green. More intriguingly, the higher Lewis acidity of Th4+ facilitates the transformation of EuxTb1-x-BDC-OH into a UiO-type Th-MOF via a dissolution-recrystallization mechanism. This process results in a gradual reduction of characteristic Ln3+ emissions and the emergence of blue color ligand-based fluorescence, thereby leading to selective fluorochromic responses with increasing Th4+ concentrations and enabling visible detection of Th4+ cations. Additionally, a custom-built portable optoelectronic device is fabricated, which directly converts luminescence colors into red-green-blue (RGB) values. This device enables easy quantification of Th4+ concentrations without the need for complex instrumentation.

Coalbed methane reservoir properties assessment and 3D static modeling for sweet-spot prediction in Dahebian block, Liupanshui Coal field, Guizhou Province, southwestern China

Guizhou Province has many multi-layer, thin-thick coal seams; however, complex geology, incomplete reservoir characterization, and sweet-spot selection technology prevent large-scale coalbed methane (CBM) development. This study evaluates the CBM reservoir properties within the Dahebian block using logging data, coal sample analysis, and well-testing data and develops a 3D static reservoir properties model to analyze their spatial and vertical propagation. A sweet spot evaluation model was established using a multi-level fuzzy method based on 9 parameters extracted from a 3D static reservoir properties model. The coal measure has 22 coal seams, and seams >2 m thick have 2 or 3 thin non-coal layers intercalated. Coal seams 1#, 7#, and 11# are thin to thick, deeply buried, widely distributed, and have high gas content and saturation. Undeformed and cataclastic coal predominates the coal seam 1# and 7#, whereas coal seam 11# is dominated by cataclastic and granulated coal. The southern and central parts of coal seam 7# and 11# have less tectonically deformed coal (TDC). Coal seams 1# and 7# have low permeability relative to seam 11# and are localized, while coal seams 11# have high permeability, are extensively distributed, and contain substantial gas concentrations. Comparative analysis of evaluation scores and CBM production statistics shows that high scores indicate sweet spots for CBM development. Sweet-spot potential was classified as high, medium, and low. Scattered sweet spots are found in single layers, while combined development (1# + 7#+11#) reveals a wider high-potential area in the south-central region. This area, featuring deep, thick coal seams, high permeability, gas saturation, reservoir pressure, and low TDC proportion, indicates significant development potential. This study validates CBM development statistics, identifies future development areas, and guides the development of geologically complex Guizhou CBM.

The uprisal of a lost endemic edible species, Micromeria cymuligera: Comprehensive elucidation of its biological activities and phytochemical composition

Bioactive plant species are gaining scientific importance daily. New natural goods with added value are encouraged by the link between health, modern and traditional lifestyles. For about 145 years, Micromeria cymuligera, a Turkish endemic, was presumed extinct. For years, no specimen of this medicinal and fragrant species has been found in the region, but rich populations have lately been found in Bingöl province, Turkey. Like other Micromeria species, M. cymuligera has been used in tea and cooking due to its powerful bioactivities and scent. This is the first study to look at the complete quantification of bioactive phytochemicals, antioxidant capacity, and enzyme inhibitory evaluation of the long-thought-to-be-extinct M. cymuligera species. Using a previously established and validated LC-MS/MS methodology, this study aimed to screen the bioactive phytochemicals of M. cymuligera and assess its diverse antioxidant and enzyme inhibitory properties. The EtOH extract of the species had substantial concentrations of rosmarinic acid (13.05 mg/g extract), quinic acid (4.57 mg/g extract), chlorogenic acid (2.34 mg/g extract), and cynaroside (2.37 mg/g extract), according to LC-MS/MS data. Furthermore, it was shown that the species had relatively high total phenolic-flavonoid contents (40.94 ± 0.38 mgGAEs/g extract and 5.13 ± 0.29 mgREs/g extract, respectively). The extract shown noteworthy activity (82.00 ± 0.74, 126.23 ± 3.43, 48.33 ± 1.36, and 35.89 ± 0.44 mgTEs/g extract in FRAP, CUPRAC, ABTS, and DPPH respectively) in all antioxidant assays when the bioactivity experiments on M. cymuligera were considered. Furthermore, of all the enzyme inhibitory tests (tyrosinase, α-amylase, α-glucosidase, BChE, and AChE), the species demonstrated outstanding inhibitory action against tyrosinase (70.80 ± 1.34 mgKAE/g extract).

Phytoplankton growth and grazing dynamics during anomalous heat wave and suppressed upwelling conditions in the southern California Current

We investigated phytoplankton dynamics in the southern California Current System (SCCS) in August 2014 during the early phase of the 2014-15 marine heat wave (MHW). Multi-day experiments were conducted at three inshore and two offshore sites, with daily depth profiles of dilution incubations on a drifting array to determine growth and grazing rates and shipboard assessments of nutrient effects. Picophytoplankton populations were analyzed by flow cytometry and eukaryotic phytoplankton by 18 S sequencing. Mixed-layer nutrients were low across the region, but inshore sites had substantial nitrate concentrations and prominent Chla maxima in the lower euphotic zone. Shoreward transport of warm-stratified waters from the offshore suppressed coastal upwelling and shifted picophytoplankton distributions toward increased onshore abundance of Prochlorococcus and decreased Synechococcus and picoeukaryotes. These trends were reinforced by higher-than-average growth of Prochlorococcus at inshore sites and higher grazing of Synechococcus and picoeukaryotes. Prasinophytes (Chlorophyceae) were notably important among eukaryotic taxa, and pennates replaced centric taxa as the dominant diatoms in inshore waters compared to normal upwelling. Despite substantial spatial variability in community composition, offshore and inshore experimental locations both showed growth-grazing balances, with microzooplankton consuming similar percentages (80%) of primary production. We thus confirm expectations that the 2014-15 MHW resulted in greater trophic flow through the microbial food web at the expense of reduced direct phytoplankton (Chla) consumption by mesozooplankton. However, impacts on mesozooplankton energy budgets were partially offset by increased trophic flow through protistan microzooplankton and higher phytoplankton C:Chla.

Geographies and determinants of rent burden: A regional economic analysis of the U.S. metropolitan landscape

Rental housing affordability, a growing topic in interdisciplinary scholarship, remains relatively peripheral to geography and regional science. This article focuses on geographies of rent burden and factors affecting it at the metropolitan level in the conterminous U.S. By conducting cartographic and regression analyses, we examine relationships between rent burden and numerous related aspects derived from scholarly work. Besides offering a new measurement of rent burden, we put a special emphasis on regional economic specializations as potential predictors of rent burden’s intensity. The relationship between these two have not been studied in existing scholarship. Our results indicate that the most consistent determinants of more intense rent burden in numerous models include higher housing values and poverty rates, substantial shares of racial/ethnic minorities, and family structure represented by lower percent married. Regarding economic specializations, we find that manufacturing is a strong predictor of lower rent burden in most models, with its effect demonstrating an opposite direction—higher rent burden occurs in metropolises not specializing in manufacturing. Simultaneously, metropolises with substantial concentrations of employment in (i) education and medicine and (ii) arts, entertainment, and recreation exhibit higher rent burden and most of these metropolises are mid- and small-sized.

Utilization of the Dicarbonyl Compounds 3-Deoxyglucosone and 3-Deoxymaltosone during Beer Fermentation by Saccharomyces Yeasts

In beer production, 1,2-dicarbonyl compounds such as 3-deoxyglucosone (3-DG) and 3-deoxymaltosone (3-DM) are formed via Maillard reaction or caramelization especially during malt kilning or wort boiling, resulting in substantial concentrations in wort. Consequences of dicarbonyl compounds for yeast metabolism are widely unknown. In the present study, the handling of 3-DG and 3-DM by Saccharomyces strains from different habitats in wort and during beer fermentation was investigated. We show that beer yeast strains induced a faster 3-DG degradation in Pilsner wort and were additionally more stress-resistant to 3-DG compared to yeasts isolated from natural habitats. In fermentation experiments comparing a light wort and a dark wort prepared from malt extracts, it could be shown that high levels of 3-DM in dark wort influence the utilization of 3-DG by yeasts, and thus higher levels of 3-DG remain in the wort. Beer yeast strains showed an increased formation of 3-deoxyfructose (3-DF) with up to 220 µM, which is possibly due to a preferred metabolization of 3-DM, as indicated by the low degradation rate of 3-DG. In contrast, yeasts isolated from natural habitats produced significantly lower amounts of 3-DF. This suggests an adaptation of technologically used yeasts to metabolization of dicarbonyl compounds, possibly as a result of beer yeast domestication.

Assessment of anthropogenic pollution in Guanabara Bay (SE Brazil) through biogeochemical data and stable isotope mixing models.

This work intends to identify pollution sources along the margins of Guanabara Bay (GB; SE Brazil) through a multiproxy approach and Bayesian stable isotopic mixture model (BSIMM). For this purpose, 33 surface sediment samples were collected and analyzed for granulometry, geochemistry (heavy metals, total organic carbon-TOC, stable isotopes of carbon and nitrogen-δ13C and δ15N, Rock-Eval pyrolysis parameters-REPP), and physicochemical parameters. Metal concentrations (E) dissolved in water (EW), adsorbed by organic matter (EOM) and by Mn hydroxides (EMn), and total extracted concentrations (ET) were analyzed. Sampling was conducted in 2018 after an oil spill from Reduc Oil Refinery. Potential Ecological risk index (PERI), based on metals, classified 85% of the analyzed stations as having moderate to considerable ecological risk. The metals with the potential to cause the highest ecological risk were CdW, CdOM, PbOM, and HgOM. The combination of BSIMM and REPP data was an effective proxy for oil spill detection by indicating the presence of polycyclic aromatic hydrocarbons (PAHs). Relatively high TOC contents suggested that the analyzed stations are eutrophicated environments. BSIMM discriminated three groups of stations with different sources of organic matter (OM), endorsing the result previously shown by the cluster analysis: (A) Niterói region, Botafogo marina, Glória marina, Fiscal and Fundão islands with diffuse sources of OM, including marine phytoplankton and material of continental origin from highly polluted rivers and domestic sewage; (B) region near Fundão and Governador islands and Mangue Channel outlet with OM (≃70%) supplied by highly polluted streams and a small contribution of PAHs; (C) Duque de Caxias and Botafogo-Urca inlet with significant contributions of PAHs, materials from C-3 plants and rivers polluted by urban sewage. Results of linear regressions in conjunction with BSIMM indicate that HgMn and PbOM mainly affect Group A's stations. Although the eastern margin of GB (Niterói; Group A) showed greater oceanic interaction than the other groups, it presented substantial concentrations of metals, potentially harmful (i.e., Hg and Pb) to marine biota and human health.

Estimates of lithium mass yields from produced water sourced from the Devonian-aged Marcellus Shale

Decarbonatization initiatives have rapidly increased the demand for lithium. This study uses public waste compliance reports and Monte Carlo approaches to estimate total lithium mass yields from produced water (PW) sourced from the Marcellus Shale in Pennsylvania (PA). Statewide, Marcellus Shale PW has substantial extractable lithium, however, concentrations, production volumes and extraction efficiencies vary between the northeast and southwest operating zones. Annual estimates suggest statewide lithium mass yields of approximately 1160 (95% CI 1140–1180) metric tons (mt) per year. Production decline curve analysis on PW volumes reveal cumulative volumetric disparities between the northeast (median = 2.89 X 107 L/10-year) and southwest (median = 5.56 × 107 L/10-year) regions of the state, influencing lithium yield estimates of individual wells in southwest [2.90 (95% CI 2.80–2.99) mt/10-year] and northeast [1.96 (CI 1.86–2.07) mt/10-year] PA. Moreover, Mg/Li mass ratios vary regionally, where NE PA are low Mg/Li fluids, having a median Mg/Li mass ratio of 5.39 (IQR, 2.66–7.26) and SW PA PW is higher with a median Mg/Li mass ratio of 17.8 (IQR, 14.3–20.7). These estimates indicate substantial lithium yields from Marcellus PW, though regional variability in chemistry and production may impact recovery efficiencies.