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Bacteria play a key role in sustaining the chemodiversity of marine dissolved organic matter (DOM), yet there is limited direct evidence of a major contribution of bacterial exometabolites to the DOM pool. This study tests whether molecular formulae of intact exometabolites can be detected in natural DOM via untargeted Fourier‐transform ion cyclotron resonance mass spectrometry (FT‐ICR‐MS). We analyzed a series of quantitative mixtures of solid‐phase extracted DOM from the deep ocean, of a natural microbial community and selected model strains of marine bacteria. Under standard instrument settings (200 broadband scans, mass range 92–1000 Da), 77% of molecular formulae were shared between the mesocosm and marine DOM. However, there was, Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659

Groundwater abstraction and drainage are considered to be the main drivers for the salinization of low‐lying coastal groundwater systems, while the role of past boundary conditions is less clear. In this study, 3‐D paleo‐hydrogeological variable‐density groundwater flow and salt transport modeling (“paleo‐modeling”) is applied to reconstruct the evolution of groundwater salinities during the Holocene, that is, the last 9,000 years, in Northwestern Germany. Novel aspects of this study include the consideration of highly resolved time‐variant boundary conditions in a 3‐D paleo‐modeling framework, for example, sea‐level rise, surface elevation and coastline changes, development of drainage networks and groundwater abstraction, as well as the quantification of isolated processes impacting salinization. Results show that salinization was a function of sea‐level rise from 9000 BP until 1300 CE. The creation of the dike line ∼1300 CE set the starting point for increasing anthropogenic control of the hydro(geo)logical system: changes in surface elevation and drainage of low‐lying marshes have become main drivers for salinization after 1600 CE when peat was artificially degenerated. Moreover, changes in the dike line caused by storm floods impacted the salinities. Model results for 2020 CE match well with present‐day salinity observations. Yet, salinization will continue in the future, as the hydro(geo)logical system has not reached an equilibrium. The presented paleo‐modeling framework can be viewed as a blueprint for similar low‐lying coastal groundwater systems, influenced by marine transgression and human development. Thereby, it enables the reconstruction of meaningful present‐day salinity distributions, serving as a vital basis for modeling future groundwater systems in a changing climate., Key Points: Salinization of a low‐lying coastal groundwater system during the Holocene, that is, 9000 BP until present‐day, was investigated. Sea‐level rise and the evolution of paleogeography were major controls on groundwater salinization during most of the time. Surface elevation changes due to land cultivation, as well as the development of drainage networks, control salinization since ∼1600 CE., Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659, Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347, https://doi.org/10.5281/zenodo.7633381

The interactions between barotropic tides and mesoscale processes were studied using the results of a numerical model in which tidal forcing was turned on and off. The research area covered part of the East Atlantic Ocean, a steep continental slope, and the European Northwest Shelf. Tides affected the baroclinic fields at much smaller spatial scales than the barotropic tidal scales. Changes in the horizontal patterns of the M2 and M4 tidal constituents provided information about the two-way interactions between barotropic tides and mesoscale processes. The interaction between the atmosphere and ocean measured by the work done by wind was also affected by the barotropic tidal forcing. Tidal forcing intensified the transient processes and resulted in a substantial transformation of the wave number spectra in the transition areas from the deep ocean to the shelf. Tides flattened the sea-surface height spectra down to ~ k−2.5 power law, thus reflecting the large contribution of the processes in the high-frequency range compared to quasi-geostrophic motion. The spectra along sections parallel or normal to the continental slope differ from each other, which indicates that mesoscale turbulence was not isotropic. An analysis of the vorticity spectra showed that the flattening was mostly due to internal tides. Compared with the deep ocean, no substantial scale selectivity was observed on the shelf area. Particle tracking showed that the lengths of the Lagrangian trajectories increased by approximately 40% if the barotropic tidal forcing was activated, which contributed to changed mixing properties. The ratio between the horizontal and vertical scales of motion varied regionally depending on whether barotropic tidal forcing was included. The overall conclusion is that the barotropic tides affect substantially the diapycnal mixing., Ministry of Science and Culture of Lower Saxony, BMBF

This paper discusses the economic, social and environmental benefits from using solar water heating (SWH) in Zimbabwe. By comparing different water heating technology usage in three sectors over a 25-year period, the potential of SWH is demonstrated in alleviating energy and economic problems that energy-importing countries like Zimbabwe are facing. SWH would reduce coincident electricity winter peak demand by 13% and reduce final energy demand by 27%, assuming a 50% penetration rate of SWH potential demand. Up to $250 million can be saved and CO2 emissions can be reduced by 29% over the 25-year period. Benefits are also present at individual consumer level, for the electricity utility, as well as for society at large. In the case of Zimbabwe, policy strategies that can support renewable energy technologies are already in current government policy, but this political will need to be translated into enhanced practical activities. A multi-stakeholder approach appears to be the best approach to promoting widespread dissemination of SWH technologies.

Market-based instruments are increasingly being promoted as a promising measure to face the twin challenge of biodiversity conservation and development. In the realm of market-based approaches, an important instrument is the creation of biodiversity business: ‘commercial enterprises that generate profit via activities which conserve biodiversity, use biological resources sustainably and share their benefits equitably’.

Cell size is a master trait in the functional ecology of phytoplankton correlating with numerous morphological, physiological, and life‐cycle characteristics of species that constrain their nutrient use, growth, and edibility. In contrast to well‐known spatial patterns in cell size at macroecological scales or temporal changes in experimental contexts, few data sets allow testing temporal changes in cell sizes within ecosystems. To analyze the temporal changes of intraspecific and community‐wide cell size, we use the phytoplankton data derived from the Lower Saxony Wadden Sea monitoring program, which comprises sample‐ and species‐specific measurements of cell volume from 1710 samples collected over 14 yr. We find significant reductions in both the cell volume of most species and the weighted mean cell size of communities. Mainly diatoms showed this decline, whereas the size of dinoflagellates seemed to be less responsive. The magnitude of the trend indicates that cell volumes are about 30% smaller now than a decade ago. This interannual trend is overlayed by seasonal cycles with smaller cells typically observed in summer. In the subset of samples including environmental conditions, small community cell size was strongly related to high temperatures and low total phosphorus concentration. We conclude that cell size captures ongoing changes in phytoplankton communities beyond the changes in species composition. In addition, based on the changes in species biovolumes revealed by our analysis, we warn that using standard cell size values in phytoplankton assessment will not only miss temporal changes in size, but also lead to systematic errors in biomass estimates over time., Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347, Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659, Interreg V A program Deutschland‐Nederland of the European Union, Niedersächsisches Ministerium für Wissenschaft und Kultur http://dx.doi.org/10.13039/501100010570, https://doi.org/10.5281/zenodo.5799263

International audience; Progresses in reconstructing Earth's history of biomass burning has motivated the development of a modern charcoal dataset covering the last decades through a community-based initiative called the Global Modern Charcoal Dataset (GMCD). As the frequency, intensity and spatial scale of fires are predicted to increase regionally and globally in conjunction with changing climate, anthropogenic activities and land-use patterns, there is an increasing need to further understand, calibrate and interrogate recent and past fire regimes as related to changing fire emissions and changing carbon sources and sinks. Discussions at the PAGES Global Paleofire Working Group workshop 2015, including paleoecologists, numerical modelers, statisticians, paleoclimatologists, archeologists, and anthropologists, identified an urgent need for an open, standardized, quality-controlled and globally representative dataset of modern sedimentary charcoal and other sediment-based fire proxies. This dataset fits into a gap between metrics of biomass burning indicators, current fire regimes and land cover, and carbon emissions inventories. The dataset will enable the calibration of paleofire data with other modern datasets including: data of satellite derived fire occurrence, vegetation patterns and species diversity, land cover change, and a range of sources capturing biochemical cycling. Standardized protocols are presented for collecting and analyzing sediment-based fire proxies, including charcoal, levoglucosan, black carbon, and soot. The GMCD will provide a publically-accessible repository of modern fire sediment surface samples in all terrestrial ecosystems. Sample collection and contributions to the dataset will be solicited from lacustrine, peat, marine, glacial, or other sediments, from a wide variety of ecosystems and geographic locations.

Cyclic volatile methylsiloxanes (cVMS) and short-chain chlorinated paraffins (SCCPs) use has been restricted in recent years due to environmental health concerns. Both of these classes of emerging contaminants possess long range transport potential (LRTP), highlighting the need for continuous monitoring to assess effectiveness of implemented regulations. However, emission source elucidation and understanding processes affecting atmospheric transport remain challenging. Atmospheric levels of cVMSs and SCCPs were simultaneously monitored at a background monitoring site in Norway from January–July 2020. Concentrations obtained from active air samplers ranged from 49.9 to 845 (mean: 208) pg/m3 for ƩSCCPs and from 0.4 to 3.5 (mean: 1.5), 1.1–15 (mean: 5.6) and 0.1–0.9 (mean: 0.4) ng/m3 for octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6), respectively. As SCCPs pose several challenges to analysts, different quantification methodologies and blank handling procedures were investigated to ensure reliable environmental measurements. Simulations using a Lagrangian atmospheric transport model (FLEXPART) revealed air masses impacting sampling measurements were of Oceanic origin, but periodic emission events from Europe and Russia were also observed. Seasonal pattern in cVMS concentrations was mainly driven by atmospheric degradation via hydroxyl radical reaction, whereas SCCP concentrations were more influenced by periodic anthropogenic inputs from local and continental Europe. No clear correlation could be observed with SCCP atmospheric concentrations and temperature over the entire sampling campaign. However, increased volatilization at elevated temperatures may be important with emissions originating from local sources. Higher chlorinated homologue groups dominated during the winter season and declined towards spring and summer, whereas reverse was found for the lower and more volatile chlorinated homologue groups.

Core–shell structure hybrids of carbon nanotubes (CNTs)/BaTiO3 (H-CNT-BT) and commercial multi-wall CNTs are respectively incorporated into poly(vinylidene fluoride) (PVDF) for preparing the composites near the percolation thresholds. A comprehensive investigation for CNT's dispersion and composite's conductivity is conducted between H-CNT-BT/PVDF and CNT/PVDF at different depths vertical to the injection's direction. Gradual increases of the conductivity in two composites are observed from the out-layer to the core part which infers an inhomogeneous CNT's dispersion in the interior of composites due to their migration under flow during the injection. However, the use of H-CNT-BT fillers with core–shell structure enables to reduce this inhomogeneous dispersion in the composite. Furthermore, the conductive network of CNTs in H-CNT-BT/PVDF is less sensitive to the thermal treatment than the one in CNT/PVDF composite, which infers the core–shell structure of hybrids can ameliorate the sensitivity of the conductive network. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45693.

International audience; Silicon (Si) is the second most abundant element in the Earth's crust and is an important nutrient in the ocean. The global Si cycle plays a critical role in regulating primary productivity and carbon cycling on the continents and in the oceans. Development of the analytical tools used to study the sources, sinks, and fluxes of the global Si cycle (e.g., elemental and stable isotope ratio data for Ge, Si, Zn, etc.) have recently led to major advances in our understanding of the mechanisms and processes that constrain the cycling of Si in the modern environment and in the past. Here, we provide background on the geochemical tools that are available for studying the Si cycle and highlight our current understanding of the marine, freshwater and terrestrial systems. We place emphasis on the geochemistry (e.g., Al/Si, Ge/Si, Zn/Si, delta C-13, delta N-15, delta O-18, delta Si-30) of dissolved and biogenic Si, present case studies, such as the Silicic Acid Leakage Hypothesis, and discuss challenges associated with the development of these environmental proxies for the global Si cycle. We also discuss how each system within the global Si cycle might change over time (i.e., sources, sinks, and processes) and the potential technical and conceptual limitations that need to be considered for future studies.

WBE has now become a complimentary tool in SARS-CoV-2 surveillance. This was preceded by the established application of WBE to assess the consumption of illicit drugs in communities. It is now timely to build on this and take the opportunity to expand WBE to enable comprehensive assessment of community exposure to chemical stressors and their mixtures. The goal of WBE is to quantify community exposure, discover exposure-outcome associations, and trigger policy, technological or societal intervention strategies with the overarching aim of exposure prevention and public health promotion. To achieve WBE's full potential, the following key aspects require further action: (1) Integration of WBE-HBM (human biomonitoring) initiatives that provide compre-hensive community-individual multichemical exposure assessment. (2) Global WBE monitoring campaigns to provide much needed data on exposure in low-and middle-income countries (LMICs) and fill in the gaps in knowledge especially in the underrepresented highly urbanised as well as rural settings in LMICs. (3) Combining WBE with One Health actions to enable effective interventions. (4) Advancements in new analytical tools and methodologies for WBE progression to enable biomarker selection for exposure studies, and to provide sensitive and selective multiresidue analysis for trace multi-biomarker quantification in a complex wastewater matrix. Most of all, further developments of WBE needs to be undertaken by co-design with key stakeholder groups: government organisations, health authorities and private sector.

This study describes a simple and low-cost method for fabricating novel 2–3-type composites composed of zinc flakes and polyvinylidene fluoride (PVDF) by direct wet ball-milling and hot-pressing of the mixture of raw zinc powders and PVDF powders in alcohol. It is interesting that zinc spherical powders can be changed into 2-dimensional zinc flakes in the ball-milling and parallel oriented in the polymer under the following hot-pressing process. The composites are demonstrated to have significantly higher dielectric constants than those of bulk zinc/PVDF composites, with quite low dielectric loss and good thermal stability. A mechanism of parallel-board microcapacitor is proposed to explain the relationship of microstructure and dielectric properties.

Perfluorohexane sulfonate (PFHxS) is one of the short-chain perfluoroalkyl substances (PFASs), and frequently detected in the environment, humans, and wildlife, but a detailed mechanism of toxicity has been not studied yet. In this study, a comprehensive set of polar metabolites was determined in i) the developing zebrafish embryo (4, 24, 48, 72, and 120 h post fertilization (hpf)), and ii) in the developing zebrafish after exposure to four concentrations of PFHxS (0.3, 1, 3, and 10 μM) from 24to 120 hpf. The temporal (developmental stages) distribution of individual metabolites (541 metabolites) in zebrafish provided comprehensive information about the biological roles of various metabolites in developing vertebrates such as genetic processes, energy metabolism, protein metabolism, and glycerophospholipid metabolism. PFHxS in zebrafish embryo showed time- and concentration- dependent bioaccumulation, and no baseline toxicity was expected at the test concentrations. However, effects on many metabolites were already observed at the lowest tested concentration (0.3 μM), and these effects were more pronounced at later stages of developmental (72 and 120 hpf). In addition to oxidative stress, the effects of PFHxS on zebrafish embryos were related to the disruption of the fatty acid oxidation (FAO), sugar metabolism, and other metabolic pathways. This study gave new and comprehensive information on the underlying mechanism of the toxicity of PFHxS.

Pharmaceuticals, such as glucocorticoids and antibiotics, are inadequately removed from wastewater and may cause unwanted toxic effects in the receiving environment. This study aimed to identify contaminants of emerging concern in wastewater effluent with antimicrobial or glucocorticoid activity by applying effect-directed analysis (EDA). Effluent samples from six wastewater treatment plants (WWTPs) in the Netherlands were collected and analyzed with unfractionated and fractionated bioassay testing. Per sample, 80 fractions were collected and in parallel high-resolution mass spectrometry (HRMS) data were recorded for suspect and nontarget screening. The antimicrobial activity of the effluents was determined with an antibiotics assay and ranged from 298 to 711 ng azithromycin equivalents·L−1. Macrolide antibiotics were identified in each effluent and found to significantly contribute to the antimicrobial activity of each sample. Agonistic glucocorticoid activity determined with the GR-CALUX assay ranged from 98.1 to 286 ng dexamethasone equivalents·L−1. Bioassay testing of several tentatively identified compounds to confirm their activity revealed inactivity in the assay or the incorrect identification of a feature. Effluent concentrations of glucocorticoid active compounds were estimated from the fractionated GR-CALUX bioassay response. Subsequently, the biological and chemical detection limits were compared and a sensitivity gap between the two monitoring approaches was identified. Overall, these results emphasize that combining sensitive effect-based testing with chemical analysis can more accurately reflect environmental exposure and risk than chemical analysis alone.

International audience; The relevance of considering environmental variability for understanding and predicting biological responses to environmental changes has resulted in a recent surge in variability-focused ecological research. However, integration of findings that emerge across studies and identification of remaining knowledge gaps in aquatic ecosystems remain critical. Here, we address these aspects by: (1) summarizing relevant terms of variability research including the components (characteristics) of variability and key interactions when considering multiple environmental factors; (2) identifying conceptual frameworks for understanding the consequences of environmental variability in single and multifactorial scenarios; (3) highlighting challenges for bridging theoretical and experimental studies involving transitioning from simple to more complex scenarios; (4) proposing improved approaches to overcome current mismatches between theoretical predictions and experimental observations; and (5) providing a guide for designing integrated experiments across multiple scales, degrees of control, and complexity in light of their specific strengths and limitations.

It has been suggested that domestic animals can serve as sentinels for human exposures. In this study our objectives were to demonstrate that i) silicone collars can be used to measure environmental exposures of (domestic) animals, and that ii) domestic animals can be used as sentinels for human residential exposure. For this, we simultaneously measured polycyclic aromatic hydrocarbons (PAHs) using silicone bands worn by 30 pet cats (collar) and their owner (wristband). Collars and wristbands were worn for 7 days and analyzed via targeted Gas Chromatography-Mass Spectrometry (GC-MS). Demographics and daily routines were collected for humans and cats. Out of 16 PAHs, 9 were frequently detected (>50% of samples) in both wristbands and collars, of which Phenanthrene and Fluorene were detected in all samples. Concentrations of wristbands and collars were moderately correlated for these 9 PAHs (Median Spearman's r = 0.51 (range 0.16–0.68)). Determinants of PAH concentrations of cats and humans showed considerable overlap, with vacuum cleaning resulting in higher exposures and frequent changing of bed sheets in lower exposures. This study adds proof-of-principle data for the use of silicone collars to measure (domestic) animal exposure and shows that cats can be used as sentinels for human residential exposure.

This study aimed to identify antimicrobial contaminants in the aquatic environment with effect-directed analysis. Wastewater influent, effluent, and surface water (up- and downstream of the discharge location) were sampled at two study sites. The samples were enriched, subjected to high-resolution fractionation, and the resulting 80 fractions were tested in an antibiotics bioassay. The resulting bioactive fractions guided the suspect and nontargeted identification strategy in the high-resolution mass spectrometry data that was recorded in parallel. Chemical features were annotated with reference databases, assessed on annotation quality, and assigned identification confidence levels. To identify antibiotic metabolites, Phase I metabolites were predicted in silico for over 500 antibiotics and included as a suspect list. Predicted retention times and fragmentation patterns reduced the number of annotations to consider for confirmation testing. Overall, the bioactivity of three fractions could be explained by the identified antibiotics (clarithromycin and azithromycin) and an antibiotic metabolite (14-OH(R) clarithromycin), explaining 78% of the bioactivity measured at one study site. The applied identification strategy successfully identified antibiotic metabolites in the aquatic environment, emphasizing the need to include the toxic effects of bioactive metabolites in environmental risk assessments.

The comparability of laboratories for the analysis of per- and polyfluoroalkyl substances (PFAS) was assessed in the fourth round (2018/2019) of a series of interlaboratory assessments coordinated by the United Nations Environment Programme (UNEP) in support of the Stockholm Convention quality assurance activities as to persistent organic pollutants (POPs) laboratories reporting data under this Convention. The participating laboratories were asked to analyse PFAS concentrations in a test solution of the target compounds, in the four core matrices of the global monitoring plan (GMP), human milk, human plasma, an air extract, and water, and in a sediment and a fish matrix. 39 participating laboratories submitted PFAS data for one or more test materials. The majority of the participating laboratories originated from the Asia-Pacific region, and from the 'Western European and other groups' (WEOG). Only one laboratory from the group 'Latin America and Caribbean' (GRULAC), and two from the Central and Eastern Europe (CEE) region submitted results. None of the African laboratories submitted data. The coefficients of variation (CVs) varied from 7% to 24% (mean 14%) for the test solution. Mean CVs for all matrices, except for the human plasma test material (18%), were above the satisfactory limit of 25%. The highest mean CV was found for human milk (61%). In total 1457 z-scores were assigned of which 64% were satisfactory (|z, Funding agencies:UN Environment, Economy Division, Chemicals and Waste BranchGlobal Environment Facility (GEF)

Objective: Women of reproductive age are exposed to ubiquitous chemicals such as phthalates, parabens, and per- and polyfluoroalkyl substances (PFAS), which have potential endocrine disrupting properties and might affect fertility. Our objective was to investigate associations between potential endocrine-disrupting chemicals (EDCs) and female fertility in two cohorts of women attending fertility clinics. Methods: In a total population of 333 women in Sweden and Estonia, we studied the associations between chemicals and female fertility, evaluating ovarian sensitivity index (OSI) as an indicator of ovarian response, as well as clinical pregnancy and live birth from fresh and frozen embryo transfers. We measured 59 chemicals in follicular fluid samples and detected 3 phthalate metabolites, di-2-ethylhexyl phthalate (DEHP) metabolites, 1 paraben, and 6 PFAS in >90% of the women. Associations were evaluated using multivariable-adjusted linear or logistic regression, categorizing EDCs into quartiles of their distributions, as well as with Bayesian Kernel Machine Regression. Results: We observed statistically significant lower OSI at higher concentrations of the sum of DEHP metabolites in the Swedish cohort (Q4 vs Q1, β = -0.21, 95% CI: −0.38, −0.05) and methylparaben in the Estonian cohort (Q3 vs Q1, β = -0.22, 95% CI: −0.44, −0.01). Signals of potential associations were also observed at higher concentrations of PFUnDA in both the combined population (Q2 vs. Q1, β = −0.16, 95% CI -0.31, −0.02) and the Estonian population (Q2 vs. Q1, β = −0.27, 95% CI -0.45, −0.08), and for PFOA in the Estonian population (Q4 vs. Q1, β = −0.31, 95% CI -0.61, −0.01). Associations of chemicals with clinical pregnancy and live birth presented wide confidence intervals. Conclusions: Within a large chemical mixture, we observed significant inverse associations levels of DEHP metabolites and methylparaben, and possibly PFUnDA and PFOA, with OSI, suggesting that these chemicals may contribute to altered ovarian function and infertility in women.