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Novel miniaturized Pb(II) paper-based potentiometric sensors are described using coumarin derivatives I and II as electroactive ionophores and nano vanadium pentoxide as a solid contact material for the sensitive and selective monitoring of trace lead ions. Density functional theory (DFT) confirms optimum geometries, electronic properties, and charge transfer behaviors of 1:2 Pb(II): coumarin complexes. The sensors are prepared by using two strips of 20 × 5 mm filter paper with two circular orifices. One orifice is coated with vanadium pentoxide (V2O5) nanoparticles in colloidal conductive carbon as a solid-contact, covered by a PVC membrane containing coumarin ionophore to act as a sensing probe. The other orifice is treated with Ag/AgCl in a polyvinyl butyral (PVB) film, to act as a reference electrode. Sensors with ionophores (I) and (II) exhibit Nernstian slopes of 27.7 ± 0.2 and 30.2 ± 0.2 mV/decade over the linear concentration range 4.5 × 10−7 to 6.2 × 10−3 M and 8.5 × 10−8 to 6.2 × 10−3 M, with detection limits of 1.3 × 10−7 M (26.9 ppb) and 2.1 × 10−8 M (4.4 ppb), respectively. The sensors are satisfactorily used for accurate determination of lead ions in drinking water, lead-acid battery wastewater, and electronic waste leachates. The results compare favourably well with data obtained by flameless atomic absorption spectrometry. [ABSTRACT FROM AUTHOR]

Pulp and paper wastewaters are challenging to treat due to their variability, complexity and toxicity. Membrane Bioreactor's (MBR's) provide high-quality filtrates but are subject to periods of low filterability / high capillary suction time (CST) which potentially limit their use in this application. There is a paucity of published literature concerning long-term operational issues in full-scale, industrial MBR's. We hypothesised that either changes of bacterial population, alteration/reduction of bacterial metabolism or bacterial production of extra-cellular polymers (ESPs) increased CST and reduced filterability. This study, conducted over two years at the 16.4MLD Gippsland Water Factory, was structured to inform this bacterial centric hypothesis. However, no shifts in bacterial population were seen as causative of high CST and microbial stress levels and biological activity were observed to be low during high CST and no sign of toxicity was found. The strongest correlator with CST was the concentration of colloidal Total Organic Carbon of the mixed liquor suspended solids (MLSS) supernatant (following centrifugation). The carbonaceous colloids accumulated in the supernatant were named 'Non-Centrifugable Total Organic Carbon' (NCTOC). Their accumulation in the MLSS was found be due to their biologically refractory nature and their retention by the MBR membrane. The accumulation of NCTOC typically followed a period where the influent had a high colour and a high sodium to calcium ratio, which is consistent with a pulping by-product called 'Black Liquor'. Additional experiments with Black Liquor allowed us to conclude that high CST can be produced by addition of Black Liquor. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ink-Jetted Miniaturized paper based electroanalytical device was fabricated. • ZnO nanoparticles were drop casted to modify the working electrode. • A linear range of 4 μM to 60 μM was found. • A 4.04 μM of limit of detection was within in the safe limit. • The device was tested for picric acid sensing in tap and lake water. Picric acid (PA) is one of the essential components utilized in manufacturing of explosives. Therefore, the detection of trace amount of PA is critical in forensic science, criminal investigation, military security and environmental safety. Owing to these attributes, development of a simple, rapid and point-of-care (POC) analytical method for PA detection and quantification is crucial. Herein, a low-cost, POC, ink jetted paper device has been developed for electroanalytical detection of PA. Inkjet printing is an economic fabrication process used for extruding several nanomaterials with diversified applications. By improving the ink viscosity, inkjet printers can simplify the fabrication of paper-based electrochemical sensor, and provide easy, fast, environmental friendly and viable for large scale production sensors, thereby adding its commercialization potential. In this work, a commercially available circuit board printer and an inexpensive high viscosity carbon conductive ink were used to print an electrochemical paper device. The fabricated device was used for electrochemical detection of PA using cyclic voltammetry (CV) and wave voltammetry (SWV). Various parameters like effect of potential scan rate from 10 mVs−1 to 300 mVs−1, effect of variable PA concentration effect was studied. A linear concentration range of 4 μM to 60 μM was obtained. For a working electrode of 7 mm2 surface area, the limit of detection (LOD) was 4.04 μM (922.56 ppb) which was less than the prescribed safe limit of 8 μM. Effect of interference with other chemicals was examined using SWV with the co-existing metals like zinc, lead, copper and mercury. Finally, real sample analysis for tap and lake water was successfully performed with the device. The developed cost-effective paper-based ink-jetted platform, with further fine-tuning and surface modifications, can be used for sensing various analytes as a point-of-care device. [ABSTRACT FROM AUTHOR]

Carbon tariffs are directly linked to carbon performance and have an impact on export sectors. This paper examines the relationship between carbon tariffs and carbon performance based on China's manufacturing sector, helping to visually quantify the impact of carbon tariffs and to adopt more favourable strategies to address the impact. This paper uses data from 28 manufacturing industry segments in China from 2009 to 2019, estimating carbon performance using an SBM model incorporating non-desired outputs. The panel Tobit model is also used to explore the driving role of carbon tariffs and related variables on carbon performance. The results show the following: First of all, China's manufacturing carbon performance is generally on an upward trend but is mainly driven by improvements in the light textile and machinery manufacturing industries. Secondly, in terms of drivers of carbon performance, the imposition of carbon tariffs will increase the carbon performance of China's manufacturing sector. Furthermore, R&D investment is positively correlated with carbon emission performance. The significant positive impact of export dependence is manifested in the light and textile industry. Energy intensity has a significant positive impact on the textile industry and a significant negative impact on the resource processing industry. Environmental regulations have a negative impact on the light textile industry. China should optimize the industrial chain of resource processing industry. At the same time, China should increase R&D investment in emission reduction and product upgrades, encourage the export of light and textile industrial products, increase the import of resource processing industrial products. Also, the government should formulate environmental regulatory policies that are close to the nature of the industry. [ABSTRACT FROM AUTHOR]

The EU Carbon Border Adjustment Mechanism (CBAM), which is regarded as the EU's key policy tool to address carbon leakage, might have a non-negligible impact on China's exports, as China is an important trading partner for the EU's carbon-intensive products. This paper uses the GTAP-E model to simulate the impact of the EU CBAM on China's exports to the EU from four aspects, export price, trade structure, trade value and terms of trade, by setting up multiple scenarios. The results show that the EU CBAM reduces the export prices of China's taxed sectors to the EU, and that the export prices of other sectors show the same change characteristics. The export volume of China's taxed sectors decreases differently with the export transfer effect and export inhibition effect. In terms of trade value, the EU carbon tariffs not only reduce China's export value but also lead to a reduction in EU exports. The implementation of the EU CBAM improves the terms of trade of the EU and worsens the terms of trade of China. An expansion of the scope of taxation and a change in the calculation method of carbon emissions would aggravate the change in the terms of trade. The results suggest that feasible measures should be taken to strengthen international cooperation, promote the construction of a unified national carbon market and export diversification, and establish a firm carbon emission accounting system in order to mitigate the negative impact of the EU CBAM. [ABSTRACT FROM AUTHOR]

This paper provides an overview and demonstration of emerging float-based methods for quantifying gross primary production (GPP) and net community production (NCP) using Biogeochemical-Argo (BGC-Argo) float data. Recent publications have described GPP methods that are based on the detection of diurnal oscillations in upper-ocean oxygen or particulate organic carbon concentrations using single profilers or a composite of BGC-Argo floats. NCP methods rely on budget calculations to partition observed tracer variations into physical or biological processes occurring over timescales greater than 1 d. Presently, multi-year NCP time series are feasible at near-weekly resolution, using consecutive or simultaneous float deployments at local scales. Results, however, are sensitive to the choice of tracer used in the budget calculations and uncertainties in the budget parameterizations employed across different NCP approaches. Decadal, basin-wide GPP calculations are currently achievable using data compiled from the entire BGC-Argo array, but finer spatial and temporal resolution requires more float deployments to construct diurnal tracer curves. A projected, global BGC-Argo array of 1000 floats should be sufficient to attain annual GPP estimates at 10 ∘ latitudinal resolution if floats profile at off-integer intervals (e.g., 5.2 or 10.2 d). Addressing the current limitations of float-based methods should enable enhanced spatial and temporal coverage of marine GPP and NCP measurements, facilitating global-scale determinations of the carbon export potential, training of satellite primary production algorithms, and evaluations of biogeochemical numerical models. This paper aims to facilitate broader uptake of float GPP and NCP methods, as singular or combined tools, by the oceanographic community and to promote their continued development. [ABSTRACT FROM AUTHOR]

Rapid changes in the volume and sources of discharge during the spring freshet lead to pronounced variations in biogeochemical properties in snowmelt-dominated river basins. We used daily sampling during the onset of the freshet in the Fraser River (southwestern Canada) in 2013 to identify rapid changes in the flux and composition of dissolved material, with a focus on dissolved organic matter (DOM) and mercury (Hg) dynamics. Previous time series sampling (at twice monthly frequency) of dissolved inorganic species in the Fraser River has revealed smooth seasonal transitions in concentrations of major elements and tracers of water and dissolved load sources between freshet and base flow periods. In contrast, daily sampling reveals a significant increase in dissolved organic carbon (DOC) concentration (200 to 550 µmol L-1) occurring over a matter of days, accompanied by a shift in DOM optical properties, indicating a transition towards higher molecular weight, more aromatic DOM composition. Comparable changes in DOM composition, but not concentration, occur at other times of year, un derscoring the role of seasonal climatology in DOM cycling. Concentrations of total and dissolved Hg also varied during the spring freshet period, although dissolved Hg dynamics appear to be driven by factors beyond DOM as characterized here. The time series records of DOC and particulate organic carbon (POC) concentrations indicate that the Fraser River exports 0.25-0.35% of its annual basin net primary productivity. [ABSTRACT FROM AUTHOR]

The cooking oil fume particulate (COFP) produced by indoor cooking can harm human health seriously, and therefore requires urgent monitoring and optimization. In this paper, the kitchen cooking simulation process was established by using computational fluid dynamics (CFD) based on the fluid dynamics theory. Combined with the user defined function (UDF), the spatial and temporal distributions of COFP and carbon dioxide (CO2) during the cooking process were simulated and analyzed, respectively. Both simulation results were verified using experimental data. Moreover, this paper introduces a COFP concentration correlation function that utilizes the spatiotemporal correlation between COFP and CO2 concentrations during the cooking process. The function is based on the spatiotemporal distribution of CO2 concentration. By comparing it with traditional calculations, the proposed function is shown to achieve a remarkable 70% improvement in efficiency and maintain an accuracy rate exceeding 90%. This enables the rapid analysis and control of COFP concentration through monitoring and analyzing CO2 levels in the kitchen. [ABSTRACT FROM AUTHOR]

Rising ocean temperatures will likely increase stratification of the water column and reduce nutrient input into the photic zone. This will increase the likelihood of nutrient limitation in marine microalgae, leading to changes in the abundance and composition of phytoplankton communities, which in turn will affect global biogeochemical cycles. Calcifying algae, such as coccolithophores, influence the carbon cycle by fixing CO2 into particulate organic carbon (POC) through photosynthesis and into particulate inorganic carbon (PIC) through calcification. As calcification produces a net release of CO2, the ratio of PIC/POC determines whether coccolithophores act as a source (PIC/POC > 1) or a sink (PIC/ POC < 1) of atmospheric CO2. We studied the effect of phosphorus (P-) limitation and temperature stress on the physiology and PIC/POC ratios of two subspecies of Coccolithus pelagicus. This large and heavily calcified species (PIC/POC generally > 1.5) is a major contributor to calcite export from the photic zone into deep-sea reservoirs. Phosphorus limitation did not influence exponential growth rates in either subspecies, but P-limited cells had significantly lower cellular P-content. A 5°C temperature increase did not affect exponential growth rates either, but nearly doubled cellular P-content under both high and low phosphate availability. The PIC/POC ratios did not differ between P-limited and nutrient-replete cultures, but at elevated temperature (from 10 to 15°C) PIC/POC ratios decreased by 40-60%. Our results suggest that elevated temperature may intensify P-limitation due to a higher P-requirement to maintain growth and POC production rates, possibly reducing abundances in a warmer ocean. Under such a scenario C. pelagicus may decrease its calcification rate relative to photosynthesis, resulting in PIC/POC ratios < 1 and favouring CO2-sequestration over release. Phosphorus limitation by itself is unlikely to cause changes in the PIC/POC ratio in this species. [ABSTRACT FROM AUTHOR]

The development of globalization has separated the production and consumption of products spatially, and the international trade of products has become a carrier of embodied carbon trade. This paper adopted the perspective of value-added trade to calculate the amount of embodied carbon trade of China from 2006 to 2015 and perform a structural decomposition analysis of the changes in China's embodied carbon trade. This study found that: (1) China's embodied carbon exports are much larger than its embodied carbon imports, and there are differences between countries. China imported the largest amount of embodied carbon from South Korea, and it exported the largest amount of embodied carbon to the United States. (2) The structural decomposition analysis shows that changes in the value-added carbon emission coefficient during the study period would have caused China's embodied carbon trade to decrease, and changes in value-added trade would have caused China's embodied carbon trade to increase. Therefore, countries trading with China need to strengthen their cooperation with China in energy conservation, emission reduction, and product trade. In order to accurately reflect China's embodied carbon trade, it is necessary to calculate embodied carbon trade from the perspective of value-added trade. [ABSTRACT FROM AUTHOR]

Sequestration of carbon by the marine biological pump depends on the processes that alter, remineralize and preserve particulate organic carbon (POC) during transit to the deep ocean. Here, we present data collected from the Great Calcite Belt, a calcite-rich band across the Southern Ocean surface, to compare the transformation of POC in the euphotic and mesopelagic zones of the water column. The 234Th-derived export fluxes and size-fractionated concentrations of POC, particulate inorganic carbon (PIC), and biogenic silica (BSi) were measured from the upper 1000m of 27 stations across the Atlantic and Indian sectors of the Great Calcite Belt. POC export out of the euphotic zone was correlated with BSi export. PIC export was not, but did correlate positively with POC flux transfer efficiency. Moreover, regions of high BSi concentrations, which corresponded to regions with proportionally larger particles, exhibited higher attenuation of > 51 µm POC concentrations in the mesopelagic zone. The interplay among POC size partitioning, mineral composition and POC attenuation suggests a more fundamental driver of POC transfer through both depth regimes in the Great Calcite Belt. In particular, we argue that diatom-dominated communities produce large and labile POC aggregates, which generate high export fluxes but also drive more remineralization in the mesopelagic zone.We observe the opposite in communities with smaller calcifying phytoplankton, such as coccolithophores. We hypothesize that these differences are influenced by inherent differences in the lability of POC exported by different phytoplankton communities. [ABSTRACT FROM AUTHOR]

Natural methane hydrate has often been observed in sand layers that contain no particulate organic carbon (POC), but are surrounded by organic-rich, fine-grained marine muds. In this paper, we develop a reactive transport model (RTM) of a microbially-mediated set of POC degradation reactions, including hydrolysis of POC driven by extracellular enzymes, fermentation of the resulting high-molecular weight dissolved organic carbon (HMW-DOC), and methanogenesis that consumes low-molecular weight dissolved organic carbon (LMW-DOC). These processes are mediated by two groups of microbes, fermenters and methanogens that are heterogeneously distributed in different lithologies, with the largest numbers of microbes in the large pores of coarse-grained layers. We find that the RTM can reproduce methane hydrate occurrences observed in two different geological environments, at Walker Ridge Site 313-H (Gulf of Mexico) and IODP Site U1325 (Cascadia Margin). We also find that microbes can degrade POC even if they are physically separated, as extracellular enzymes and DOC can diffuse away from where they are produced by microbes. Microbial activity is highest at relatively early times after burial at shallow depths and near lithological boundaries, where concentration gradients transport solutes to intervals that contain the most microbes. [ABSTRACT FROM AUTHOR]

Background: The study of soil organic carbon characteristics and its relationship with soil environment and vegetation types is of great significance to the evaluation of soil carbon sink provided by inland salt marshes. This paper reports the characteristics of soil organic carbon fractions in 0–50 cm soil layers at four vegetation communities of the Qinwangchuan salt marsh. Results: (1) The soil organic carbon content of Phragmites australis community (9.60 ± 0.32 g/kg) was found to be higher than that of Salicornia europae (7.75 ± 0.18 g/kg) and Tamarix ramosissima (4.96 ± 0.18 g/kg) and Suaeda corniculata community (4.55 ± 0.11 g/kg). (2) The soil dissolved organic carbon, particulate organic carbon and soil microbial biomass carbon in 0–50 cm soil layer of Phragmites australis community were higher, which were 0.46 ± 0.01 g/kg, 2.81 ± 0.06 g/kg and 0.31 ± 0.01 g/kg, respectively. (3) Soil organic carbon was positively correlated with dissolved organic carbon, particulate organic carbon, and microbial biomass carbon, and negatively correlated with easily oxidized organic carbon. (4) Above-ground biomass has a strong direct positive effect on soil organic carbon, total nitrogen and pH have a strong direct positive effect on microbial biomass carbon content, pH and average density have a strong direct negative effect on easily oxidized organic carbon, and particulate organic carbon. Conclusions: The interaction between plant community characteristics and soil factors is an important driving factor for soil organic carbon accumulation in inland salt marshes. [ABSTRACT FROM AUTHOR]

The organic carbon pool is a crucial component of the ocean carbon cycle. The study of organic carbon distribution and interannual variability in the land-sea interface can contribute to understanding the global ocean carbon cycle and ecological effects in the context of the Anthropocene and help achieve the Sustainable Development Goals (SDGs). At present, there has been a certain amount of research on the source and flux of carbon in the ocean carbon cycle, but the prediction of marine carbon is still in its infancy. In this paper, a CNN-LSTM deep learning model that takes into account spatio-temporal features was used to make a 5-year mid-long-term rolling prediction of particulate organic carbon (POC) and yellow matter (CDOM) using MODIS Level 2 semimonthly synthetic data from the official website of NASA from January 2002 to June 2020. The model uses chlorophyll-a data to adjust the parameters. The results showed that the model could also be applied to the mid-long-term rolling prediction of POC and CDOM. The model was capable of accurately predicting POC and CDOM over periods of three and two years, respectively (R > 0.5). Meanwhile, the 5-year trends of the predicted and actual values were verified using the least squares method and the Mann-Kendall trend test. The results showed that the predicted and actual values of sea surface POC and CDOM in 2015–2020 showed an overall upward trend. The surface-level POC and CDOM in the ocean are considered to be related to primary production. The mid-long-term prediction of surface seawater organic carbon in the southern South China Sea helps humans explore the regional characteristics of organic carbon in the coral reef waters of the South China Sea and study the changing trend of surface seawater organic carbon. [ABSTRACT FROM AUTHOR]

Based on the input–output table and considering the terms of import and export trade at the national level, this paper calculates China's annual direct carbon emissions and total carbon emissions from 2005 to 2015. On the one hand, the actual direct carbon emissions and actual complete carbon emissions at the national level are calculated by MRIO model; on the other hand, according to the 5-year emission reduction targets set in the Eleventh Five-Year Plan and the outline document of the Twelfth Five-Year Plan, the emission reduction targets for each year are determined by equal distribution over the years. Hence, the annual carbon intensity emission reduction targets for 2006–2010 and 2011–2015 can be determined to be 4% and 3.4%, respectively, to calculate the target direct carbon emissions and target goal for complete carbon emissions. The smaller of the two is taken as the total quota. Taking 2015 as an example, the total direct carbon quota and complete carbon quota calculated are 87.87 million tons and 71.85 million tons, respectively, which is the total amount to be allocated for inter-provincial direct carbon quota and inter-provincial complete carbon quota. Findings of the study hold pivotal implications for policy development. [ABSTRACT FROM AUTHOR]

Concentration‐discharge (C‐Q) relationships of total suspended solids (TSS), total dissolved solids (TDS), particulate organic carbon (POC), and dissolved organic carbon (DOC) were investigated in the tributaries and main‐stems of two mountainous river systems with distinct watershed characteristics (Eel and Umpqua rivers) in Northern California and central Oregon (USA). Power‐law (C = a × Qb) fits to the data showed strong transport‐limited behavior (b > 1) by TSS and POC, moderate transport limitation of DOC (b > 0.3) and chemostatic behavior (b < 0) by TDS in most streams. These contrasts led to significant compositional differences at varying discharge levels, with particle‐bound constituents becoming increasingly important (relative abundances of 50% to >90%) at high‐flow conditions. Organic carbon contents of TSS displayed marked decreases with discharge whereas they increased in TDS during high‐flow conditions. Daily and cumulative material fluxes for different coastal streams were calculated using the C‐Q relationships and showed that the delivery of transport‐limited constituents, such as TSS and POC (and DOC to a lesser degree), was closely tied to high‐discharge events and occurred primarily during the winter season. The coherence between winter fluxes and high wave‐southerly wind conditions along the coast highlights how seasonal and inter‐annual differences in fluvial discharge patterns affect the fate of land‐derived materials delivered to coastal regions. Plain Language Summary: Rivers play a key role in transporting materials from land to the ocean. In this study, we investigated several streams of different characteristics from two basins, the Eel River in Northern California and the Umpqua River in central Oregon. We measured how the concentrations of dissolved and particulate materials, including total suspended and dissolved solids and particulate and dissolved organic carbon, varied as a function of river flow. Our results show that different streams export these materials in different ways depending on the level of river flow and certain watershed characteristics. The different trends with river flow exhibited by these constituents impact the total amounts exported by rivers each year as well as the timing of their export. The latter is important because ocean conditions off the Eel and Umpqua rivers exhibit marked contrasts in winds, currents, and waves depending on the season. In the paper, we explore how the combination of the timing of export by the river and the ocean conditions offshore influences the distribution and cycling of particulate and dissolved materials from land in the coastal ocean. Key Points: Concentration‐discharge relationships for different constituents show marked variability among streams from different watershedsTotal suspended solids, particulate organic carbon, and to a lesser degree, dissolved organic carbon exhibit transport limitationThe magnitude and composition of constituent fluxes display variability at distinct time scales that affect their transport to the ocean [ABSTRACT FROM AUTHOR]

Purpose: This study is aimed at better understanding the evolution of inequality in carbon emission in intraincome and interincome groups in the world, and then to uncover the driving factors that affect inequality in carbon emission. Design/methodology/approach: The approach is developed by combining the Theil index and the decomposition technique. Specifically, the Theil index is used to measure the inequality in carbon emissions from the perspective of global and each income group level. The extended logarithmic mean Divisia index was developed to explore the driving factors. Findings: This study finds that the inequality in carbon emissions of intraincome group is getting better, whereas the inequality in carbon emission of interincome group is getting worse. And the difference in global carbon emissions between income groups is the main source of global carbon emission inequality, which is greater than that within each income group. In addition, the high-income group has transferred their carbon emissions to upper-middle income group by importing high-carbon-intensive products to meet the domestic demand, while lower-middle-income group do not fully participate in the international trade. Practical implications: To alleviate the global carbon inequality, more attention should be paid to the inequality in carbon emission of interincome group, especially the trade between high-income group and upper-middle income group. From the perspective of driving factors, the impact of import and export trade dependence on the per capita carbon emissions of different income groups can almost offset each other, so the trade surplus effect should be the focus of each group. Originality/value: In order to consider the impact of international trade, this study conducts a comprehensive analysis of global carbon emissions inequality from the perspective of income levels and introduces the import and export dependence effect and the trade surplus effect into the analysis framework of global carbon emission inequality drivers, which has not been any research carried out so far. The results of this paper not only provide policy recommendations for mitigating global carbon emissions but also provide a new research perspective for subsequent inequality research. [ABSTRACT FROM AUTHOR]

In this paper, nature‐based solutions (NBS) include: (1) natural flood management (NFM) interventions with a primary function of flood risk reduction but with additional multiple benefits for water quality improvements through the mitigation of diffuse pollution; and (2) ponds with a primary function of water quality improvement. This study assesses the ability of these NBS to trap pollutants in run‐off within two small (3.4 km2) agricultural catchments (Upper Thames, UK). The masses of sediment, phosphorus, and organic carbon trapped by 14 features (since construction 2–3 years previously) were quantified through sediment surveying and sampling. Streamflow and suspended sediment monitoring downstream of features enabled catchment yields to be calculated. The features trapped a total of 83 t sediment, 122 kg phosphorus, and 4.3 t organic carbon. Although the footprint of the features was <1% of the catchment area, they drained 44% of the total land area and captured the equivalent of 15% of the total suspended sediment yield, 10% of the total phosphorus yield, and 8% of the particulate organic carbon yield as monitored at the catchment outlet over the monitoring period. Results reveal that accumulation rates were influenced by hydrological connectivity, with greater accumulation in features constructed directly on streams (online ponds), and those offline features that filled from overbank flows. The low to moderate accumulation rates observed in offline features suggests that their floodwater storage potential is only likely to significantly reduce in the medium term, necessitating maintenance after ~10 years. Compared with topsoil in each contributing area, trapped sediment was enriched in phosphorus and carbon in the majority of features, having on average 50% higher phosphorus and 17% higher organic carbon concentrations than surrounding arable soils, highlighting its potential value for redistribution on farmland. Monitoring results demonstrate the potential of NBS, including NFM, to mitigate diffuse pollution in lowland catchments. [ABSTRACT FROM AUTHOR]

A key challenge for current‐generation Earth system models (ESMs) is the simulation of the penetration of sinking particulate organic carbon (POC) into the ocean interior, which has implications for projections of future oceanic carbon sequestration in a warming climate. This paper presents a new, cost‐efficient, mechanistic 1D model that prognostically calculates POC fluxes by carrying four component particles in two different size classes. Gravitational settling and removal/transformation processes are represented explicitly through parameterizations that incorporate the effects of particle size and density, dissolved oxygen, calcite and aragonite saturation states, and seawater temperature, density, and viscosity. The model reproduces the observed POC flux attenuation at 22 locations in the North Atlantic and North Pacific. The model is applied over a global ocean domain with seawater properties prescribed from observation‐based climatologies in order to address an important scientific question: What controls the spatial pattern of mesopelagic POC transfer efficiency? The simulated vertical POC transfer is more efficient at high latitudes than at low latitudes with the exception of oxygen minimum zones, which is consistent with recent inverse modeling and neutrally buoyant sediment trap studies. Here, model experiments show that the relative abundance of large‐sized, rapidly sinking particles and the slower rate of remineralization at high latitudes compensate for the region's lack of calcium carbonate ballast and the cold‐water viscous resistance, leading to higher transfer efficiencies compared to low‐latitude regions. The model could be deployed in ESMs in order to diagnose the impacts of climate change on oceanic carbon sequestration and vice versa. Key Points: A new, dynamic marine particle cycling model reproduces the observed attenuation of sinking particulate organic carbon fluxes at 22 locationsParticle properties, ocean temperature, and to a lesser extent, seawater viscosity explain most of the large‐scale differences in mesopelagic carbon transfer efficiencyParticles transport organic carbon downward more efficiently at high latitudes than at low latitudes, consistent with recent studies [ABSTRACT FROM AUTHOR]

Purpose: Total organic carbon (TOC), dissolved organic carbon (DOC) and other physicochemical parameters of the Birim River, which serves for drinking and domestic purposes for rural mining communities, were analysed to assess the suitability of water quality for human consumption. Design/methodology/approach: In total, 40 samples were collected from 20 sampling sites during the rainy season from July to September and the dry season from December to February in addition to two repeat samples and two blank samples. Samples were analysed for physiochemical parameters and the results were compared with World Health Organisation standards (WHO). Findings: Data obtained for both rainy and dry seasons indicated TOC ranged from 1.1 to 7.3 mg/L and DOC 1–7.2 mg/L; pH, 5.6–8.63; temperature, 23.3–29.3°C; turbidity, <1.00–869NTU; apparent colour, <2.5–600 mg/L Pt-Co; true colour <2.5–150 mg/L Pt-Co; alkalinity, 27.8–80.4 mg/L; total suspended solids, <1.00–998 mg/L; electrical conductivity, 82–184 µS/cm; and bicarbonate, 33.9–98.1 mg/L. Particulate organic carbon (POC) was constituted between 1 and 10% of the TOC. Values for pH, turbidity, total suspended solids, and true colour indicated contamination of the river. p -value of <0.05 between seasons for the physicochemical parameters also suggests that the water is polluted. Practical implications: Water from the Birim River is unsuitable for human consumption and may constitute a serious health risk to the consumers. Originality/value: The paper yields immense value to inhabitant of communities using surface water affected by mining activities, policy makers in sustainability. It warns of the unsuitability of water from the Birim River for human consumption due to the potential health risk to consumers. [ABSTRACT FROM AUTHOR]

Multiscale structures are found in nature to impart brilliant structural colors with integrated properties of multiple optical elements. However, it remains challenging to build more than one optical element into artificial photonic materials in practical manufacturing. Here, hierarchical disordered photonic superstructures (HDPSs) with optical properties arising from tailored interplay of thin‐film interference (TFI) and coherent scattering from amorphous colloidal arrays (ACAs) are fabricated through the combined use of infiltration‐driven colloidal assembly and micro‐imprinting. Uniform thin ACA films with TFI effects (ACA‐TFIs) are first coated on premium glossy photo papers, displaying near‐isotropic colors under natural light and mixed colors upon specular lighting due to the duplex optical effects. Such collective effects are easily modulated by the film thicknesses of ACA‐TFIs. Also, micro‐imprinting that can remove a patterned monolayer of particles from ACA‐TFI films causes suppressed TFI in the imprinted regions, leading to HDPS films with encoded optical features. Collectively, HDPS anti‐counterfeiting labels with covert and sophisticated optical coding are achieved and their enhanced complexity results in infinite possible optical features that are virtually impractical to forge, opening new avenues to high‐level security applications. [ABSTRACT FROM AUTHOR]

There is a gap between the need for city-wide air-quality simulations considering the intra-urban variability and mircoscale dispersion features and the computational capacities that conventional urban microscale models require. This gap can be bridged by targeting model applications on the gray zone situated between the mesoscale and large-eddy scale. The urban dispersion model CAIRDIO is a new contribution to the class of computational-fluid dynamics models operating in this scale range. It uses a diffuse-obstacle boundary method to represent buildings as physical obstacles at gray-zone resolutions in the order of tens of meters. The main objective of this approach is to find an acceptable compromise between computationally inexpensive grid sizes for spatially comprehensive applications and the required accuracy in the description of building and boundary-layer effects. In this paper, CAIRDIO is applied on the simulation of black carbon and particulate matter dispersion for an entire mid-size city using a uniform horizontal grid spacing of 40 m. For model evaluation, measurements from five operational air monitoring stations representative for the urban background and high-traffic roads are used. The comparison also includes the mesoscale host simulation, which provides the boundary conditions. The measurements show a dominant influence of the mixing layer evolution at background sites, and therefore both the mesoscale and large-eddy simulation (LES) results are in good agreement with the observed air pollution levels. In contrast, at the high-traffic sites the proximity to emissions and the interactions with the building environment lead to a significantly amplified diurnal variability in pollutant concentrations. These urban road conditions can only be reasonably well represented by CAIRDIO while the meosocale simulation indiscriminately reproduces a typical urban-background profile, resulting in a large positive model bias. Remaining model discrepancies are further addressed by a grid-spacing sensitivity study using offline-nested refined domains. The results show that modeled peak concentrations within street canyons can be further improved by decreasing the horizontal grid spacing down to 10 m , but not beyond. Obviously, the default grid spacing of 40 m is too coarse to represent the specific environment within narrow street canyons. The accuracy gains from the grid refinements are still only modest compared to the remaining model error, which to a large extent can be attributed to uncertainties in the emissions. Finally, the study shows that the proposed gray-scale modeling is a promising downscaling approach for urban air-quality applications. The results, however, also show that aspects other than the actual resolution of flow patterns and numerical effects can determine the simulations at the urban microscale. [ABSTRACT FROM AUTHOR]

The distribution pattern and flux variation of POC in the continental shelf seas are essential for understanding the carbon cycle in marginal seas. The hydrodynamic environment and complicated estuarine processes in the East China Sea result in challenging estimates and substantial spatio-temporal variability in terms of POC concentrations. A hybrid retrieval model based on the mutual combination of the color index algorithm (CIPOC) and the empirical band ratio algorithm was applied in this study to effectively and dynamically monitor the surface POC concentration in the East China Sea in a long-term series for the first time using MODIS/Aqua remote sensing satellite data from 2003 to 2020. A hybrid retrieval model based on the mutual combination of the color index algorithm (CIPOC) and the empirical band ratio algorithm was applied in this study. The MODIS/Aqua remote sensing satellite data from 2003 to 2020 were employed for the first time to dynamically monitor the surface POC concentrations in the East China Sea for a long time series. The results demonstrated that the performance (R2 = 0.84, RMSE = 156.14 mg/m3, MAPE = 43.30%, bias = −64.79 mg/m3) exhibited by this hybrid retrieval algorithm confirms the usability of inversion studies of surface POC in the East China Sea. Different drivers such as river discharge, phytoplankton, wind, and the sea surface current field jointly influence the spatial and temporal distribution of POC concentrations in the East China Sea. This paper also verifies that the hybrid algorithm can be applied to retrieval tasks for POC in different seas with similar optical properties to the waters of the East China Sea. In conclusion, the long-term series East China Sea POC data record, which was established based on MODIS/Aqua, provides supplementary information for in-situ sampling, which will aid the long-term monitoring of POC fluxes in shelf seas. At the same time, it has also improved our understanding of the transport and spatio-temporal variability of POC in the East China Sea, enhancing our comprehension of the impact of POC on environmental changes and carbon cycling in marginal seas. [ABSTRACT FROM AUTHOR]

The Rhône River is among the main rivers of western Europe and the biggest by freshwater discharge and sediment delivery to the Mediterranean Sea. Its catchment is characterized by distinct hydrological regimes that may produce annual sediment deliveries ranging from 1.4 to 18.0 Mt yr -1. Its course meets numerous dams, hydro and nuclear power plants as well as agricultural, urban and industrial areas. Moreover, with the climatic crisis we are currently facing, it is proven that the occurrence and the intensity of extreme events (floods or droughts) will increase. Therefore, it is crucial to monitor the concentrations and fluxes of suspended particulate matter (SPM) and associated contaminants to study the current trends and their evolution. In the Rhône River (from Lake Geneva to the Mediterranean Sea), a monitoring network of 15 stations (3 on the Rhône River and 12 on tributaries) has been set up in the past decade by the Rhône Sediment Observatory (OSR) to investigate the concentrations and the fluxes of SPM and associated contaminants as well as their sources. The main purpose of the OSR is to assess the long-term trend of the main contaminant concentrations and fluxes, and to understand their behavior during extreme events, such as floods or dam flushing operations. The dataset presented in this paper contains the concentrations and fluxes of SPM as well as the concentrations and fluxes of several particle-bound contaminants of concern, e.g., polychlorinated biphenyl (PCB), trace metal elements (TME) and radionuclides, the particle size distribution and the particulate organic carbon of SPM. Sediment traps or continuous flow centrifuges were used to collect sufficient amount of SPM in order to conduct the measurements, and data completion was applied to reconstruct missing values. This observatory is on-going since 2011 and the database is regularly updated. All the data are made publicly available in French and English through the BDOH OSR database at 10.15454/RJCQZ7 (Lepage et al., 2021). [ABSTRACT FROM AUTHOR]

The influence of carbon black (CB) structure and surface area on key rubber properties such as monotonic stress-strain, cyclic stress–strain, and dynamic mechanical behaviors are investigated in this paper. Natural rubber compounds containing eight different CBs were examined at equivalent particulate volume fractions. The CBs varied in their surface area and structure properties according to a wide experimental design space, allowing robust correlations to the experimental data sets to be extracted. Carbon black structure plays a dominant role in defining the monotonic stress–strain properties (e.g., secant moduli) of the compounds. In line with the previous literature, this is primarily due to strain amplification and occluded rubber mechanisms. For cyclic stress–strain properties, which include the Mullins effect and cyclic softening, the observed mechanical hysteresis is strongly correlated with carbon black structure, which implies that hysteretic energy dissipation at medium to large strain values is isolated in the rubber matrix and arises due to matrix overstrain effects. Under small to medium dynamic strain conditions, classical strain dependence of viscoelastic moduli is observed (the Payne effect), the magnitude of which varies dramatically and systematically depending on the colloidal properties of the CB. At low strain amplitudes, both CB structure and surface area are positively correlated to the complex moduli. Beyond ~2% strain amplitude the effect of surface area vanishes, while structure plays an increasing and eventually dominant role in defining the complex modulus. This transition in colloidal correlations reflects the transition in stiffening mechanisms from flexing of rigid percolated particle networks at low strains to strain amplification at medium to high strains. By rescaling the dynamic mechanical data sets to peak dynamic stress and peak strain energy density, the influence of CB colloidal properties on compound hysteresis under strain, stress, and strain energy density control can be estimated. This has considerable significance for materials selection in rubber product development. [ABSTRACT FROM AUTHOR]

Because the carbon load inside a diesel particulate filters (DPF) affects the DPF regeneration, and the carbon load recognition is significant for the particulate matter (PM) emission control. It is necessary to investigate an on-board DPF carbon load recognition method because the carbon load cannot be directly measured by sensors. Aiming to build a DPF carbon load prediction model adopting the deep learning method, this paper proposes a DPF carbon load identification model based on different experimental parameters using a layered one dimension convolutional neural network (1D-CNN) method. To improve data validity, this paper adopts two data-processing methods. The data pre-processing adopts data splicing method to complete the construction of the original sample set, and the data after-processing uses wavelet packet transform method to establish the feature sample sets. The model adopts the optimal feature dataset constructed by three input parameters, i.e., temperature difference, pressure difference, and exhaust mass flow, and has both high training accuracy and test accuracy above 90 %. The pressure difference is the most important influencing input parameter, and the three-parameter sample set (Δ T + Δ P + Q) has great recognition accuracy and good model stability with the high training accuracy and test accuracy as well as less iteration. • A heavy-duty diesel engine was tested under various conditions of carbon load inside DPF. • The data processing was done by two methods: data splicing and wavelet packet transform. • We proposed a DPF carbon load identification model based on a one-dimension CNN method. • The model adopts 3 parameters, and the 3-parameter sample set has optimal performance. • The 1D-CNN model has both high training accuracy and test accuracy above 90 %. [ABSTRACT FROM AUTHOR]

The current paper studies the dynamics and age of the Triangle du Tacul (TDT) ice apron, a massive ice volume lying on a steep high-mountain rock wall in the French side of the Mont-Blanc massif at an altitude close to 3640 m a.s.l. Three 60 cm long ice cores were drilled to bedrock (i.e. the rock wall) in 2018 and 2019 at the TDT ice apron. Texture (microstructure and lattice-preferred orientation, LPO) analyses were performed on one core. The two remaining cores were used for radiocarbon dating of the particulate organic carbon fraction (three samples in total). Microstructure and LPO do not substantially vary with along the axis of the ice core. Throughout the core, irregularly shaped grains, associated with strain-induced grain boundary migration and strong single maximum LPO, were observed. Measurements indicate that at the TDT ice deforms under a low strain-rate simple shear regime, with a shear plane parallel to the surface slope of the ice apron. Dynamic recrystallization stands out as the major mechanism for grain growth. Micro-radiocarbon dating indicates that the TDT ice becomes older with depth perpendicular to the ice surface. We observed ice ages older than 600 year BP and at the base of the lowest 30 cm older than 3000 years. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) is an emerging acknowledged alternative treatment for multiple cancers. However, the efficiency of PDT is lower in tumors with imperfect vascular systems under hypoxia because anticancer therapy mediated by reactive oxygen species (ROS) is highly dependent on an adequate and sustained O2 supply. In this paper, Rattle-type Fe3O4@SiO2 mesoporous spheres are prepared using colloidal carbon spheres as templates to load artemisinin (ART) and the chlorophyll photosensitizer HNPa for localized ROS-generating therapy. HNPa was firstly reported by our group previously as a highly soluble drug and an excellent tissue penetrant. ART was considered to generate ROS based on a pH-mediated Fenton-like process. Our research shows that Fe2+ can be easily released from the Fe3O4@SiO2 nanocarrier in the tumor microenvironment by weak acidic etching, and the reaction of ART with Fe2+ from Fe3O4@SiO2-ART-HNPa can continue to perform curative functions even in the hypoxic tumor environment after PDT. Moreover, it was found that NIR light irradiation can partly enhance the production of ROS for enhanced anticancer therapy. All these results show the promise of this smart strategy to conquer the existing barriers of PDT. [ABSTRACT FROM AUTHOR]

The rationally structural engineering is an efficient strategy to improve the comprehensive performance of potassium‐ion storage anode materials. In this paper, a hybrid with hollow FeS2 nanoparticles anchored into the 3D carbon skeleton (labeled as H‐FeS2@3DCS) is successfully constructed through two critical steps of in situ chemical deposition and anion‐exchange reaction strategies. In the former, the water‐soluble Na2CO3 crystals are used as hard templates for the preparation of 3DCS, while Fe3+‐containing aqueous solutions are utilized to remove the Na2CO3 templates. Interestingly, the intense collision between Fe3+ and CO32‐ in aqueous solution produces nanoscale Fe(OH)3 colloidal particles, which are firmly anchored into the pores of the carbon skeleton to form a "lotus‐seed"‐like nanostructure. In the latter case, a central void space is created inside the FeS2 nanoparticles due to the different diffusion rates of S‐anions and Fe‐cations during the subsequent sulfidation process. Thanks to this unique composition model, the H‐FeS2@3DCS hybrid not only alleviates the volume expansion efficiently by rationally hollow structure design, but also provides spacious "roads" (3D carbon skeleton) and "houses" (hollow FeS2 nanoparticles) for fast K‐ion transition and storage. As the anode of PIBs and PIHCs, the resultant H‐FeS2@3DCS electrode delivers an obviously enhanced K‐ions storage performance over state‐of‐the‐art. [ABSTRACT FROM AUTHOR]

Finding ways to keep global warming under 1.5 degrees Celsius is urgent and will need a portfolio of solutions. Seaweeds are marine photosynthetic organisms that humans harvest either from the wild or farm, to be used in many applications and providing various ecosystem services. Large scale farming of seaweeds for absorbing carbon has lately been promoted as a climate "fix". The major shortcomings of this argument relate to the idea that a carbon sink function should exist through carbon accumulation in seaweed biomass simultaneously as seaweeds are consumed as food by humans, fed to animals, or used in many alternative applications. This carbon instead enters the fast carbon cycle and does not provide any "carbon sink" function. Radical suggestions of intentionally transfer of farmed seaweeds to the deep-sea to accomplish a longer removal are highly questionable from feasibility, economic, ecosystem effects and ethical resource use perspectives. Development of "ocean forests" for carbon capturing through farming should not be compared to forests on land as these provide carbon removal from the atmosphere at sufficiently long time scales to be qualified as carbon sequestration - thus making a difference related to reducing atmospheric greenhouse gas concentrations. Seaweeds can, however, play a role in reducing greenhouse gas emissions from the overall food system through carbon offset - i.e. if replacing food, feed, and/or materials that have larger carbon footprints. The fate/cycling of carbon as particulate and dissolved matter from both farmed and wild seaweeds, are however not fully understood, especially with respect to pathways and time scales relevant for carbon removal/storage. Another potential pathway for their role in decarbonization may be through reducing enteric methane emissions from ruminants and also through bioenergy production. More research is, however, needed for understanding the contributions from such interventions. Presenting seaweed farming as a quick fix for the climate risks facilitating misdirected investments (for carbon abatement solutions) and reducing demand for specific research and technological development that will be needed for increasing our understanding about seaweeds' contribution to food/feed systems and additional sustainability services and benefits. Supplemental data for this article is available online at https://doi.org/10.1080/23308249.2022.2048792. [ABSTRACT FROM AUTHOR]

This study analyzes Diesel Oxidation Catalyst (DOC) and Carbon Diesel Particulate Filter (CDPF) after-treatment systems integrated into a WARTSILA W20DF marine dual-fuel engine. The CDPF was coated with a non-precious metal catalyst whose catalytic redox performance improved with increasing temperature. The carbon particulate matter combustion reached up to 12.5 mg/s at 800 K and over 20 mg/s at 900 K. Then, the W20DF running at 230 kW, 450 kW, 680 kW, and 810 kW with 1000 rpm; a Tisch 10-8xx; and an AVL SPC 478 were used to sample and analyze the carbon particulate matter (CPM) before and after DOC + CDPF. The gaseous emissions (O2, CO2, CO, HC, NOx, and NO2) were analyzed with the flue gas analyzer AVL i60. The results show that the collected carbon particulate matter simultaneously became darker as the load decreased. This study finds that the maximum amount of CPM per unit volume of exhaust gas occurs under 50% working conditions and the lowest amount under 90% working conditions. After DOC + CDPF treatment with a non-precious metal coating, the CPM was reduced by about 50%. Furthermore, this type of catalyst's efficiency rises with the temperature increase. The CPM combustion efficiency reached up to 20 mg/s at 900 K. The other gas components in the exhaust gas before and after DOC + CDPF also changed. These research results have a significant reference value for DOC + CDPF optimization to decrease the carbon particulate matter in marine engines. [ABSTRACT FROM AUTHOR]

Thermal fume formation is a problem in manganese ferroalloy production and the metal production industry at large. A better understanding of the mechanisms of fume formation and the operational parameters affecting the fume formation rate may help in reducing and managing fuming. This paper aims to investigate the effects of oxygen content and gas flow rate on the fuming rate and fume particulate properties for liquid high-carbon ferromanganese. The fuming rates were attained experimentally by measuring the fume flux with respect to oxygen content and gas velocity above the metal melt. The generated fumes were also characterized in terms of particle size and element distribution between fume and melt. The fuming rates were found to steadily increase with increasing oxygen content and flow rate of the gas up to a point where the curve flattens, following theoretical predictions. However, the highest flux values measured were above the theoretical limitations of the evaporation flux in vacuo given the alloy bulk composition. It is hypothesized that the high rate of fuming is caused by an increased manganese activity at the alloy surface due to local decarburization of the alloy in contact with the oxidizing gas. [ABSTRACT FROM AUTHOR]

Ice-nucleating particles (INPs) have a large impact on the climate-relevant properties of clouds over the oceans. Studies have shown that sea spray aerosols (SSAs), produced upon bursting of bubbles at the ocean surface, can be an important source of marine INPs, particularly during periods of enhanced biological productivity. Recent mesocosm experiments using natural seawater spiked with nutrients have revealed that marine INPs are derived from two separate classes of organic matter in SSAs. Despite this finding, existing parameterizations for marine INP abundance are based solely on single variables such as SSA organic carbon (OC) or SSA surface area, which may mask specific trends in the separate classes of INP. The goal of this paper is to improve the understanding of the connection between ocean biology and marine INP abundance by reporting results from a field study and proposing a new parameterization of marine INPs that accounts for the two associated classes of organic matter. The PEACETIME cruise took place from 10 May to 10 June 2017 in the Mediterranean Sea. Throughout the cruise, INP concentrations in the surface microlayer (INPSML) and in SSAs (INPSSA) produced using a plunging aquarium apparatus were continuously monitored while surface seawater (SSW) and SML biological properties were measured in parallel. The organic content of artificially generated SSAs was also evaluated. INPSML concentrations were found to be lower than those reported in the literature, presumably due to the oligotrophic nature of the Mediterranean Sea. A dust wet deposition event that occurred during the cruise increased the INP concentrations measured in the SML by an order of magnitude, in line with increases in iron in the SML and bacterial abundances. Increases in INPSSA were not observed until after a delay of 3 days compared to increases in the SML and are likely a result of a strong influence of bulk SSW INPs for the temperatures investigated (T=-18 ∘C for SSAs, T=-15 ∘C for SSW). Results confirmed that INPSSA are divided into two classes depending on their associated organic matter. Here we find that warm (T≥-22 ∘C) INPSSA concentrations are correlated with water-soluble organic matter (WSOC) in the SSAs, but also with SSW parameters (particulate organic carbon, POCSSW and INPSSW,-16C) while cold INPSSA (T<-22 ∘C) are correlated with SSA water-insoluble organic carbon (WIOC) and SML dissolved organic carbon (DOC) concentrations. A relationship was also found between cold INPSSA and SSW nano- and microphytoplankton cell abundances, indicating that these species might be a source of water-insoluble organic matter with surfactant properties and specific IN activities. Guided by these results, we formulated and tested multiple parameterizations for the abundance of INPs in marine SSAs, including a single-component model based on POCSSW and a two-component model based on SSA WIOC and OC. We also altered a previous model based on OCSSA content to account for oligotrophy of the Mediterranean Sea. We then compared this formulation with the previous models. This new parameterization should improve attempts to incorporate marine INP emissions into numerical models. [ABSTRACT FROM AUTHOR]

In line with the strategy of transforming existing municipal wastewater treatment plants (WWTP) from disposal facilities into systems for using domestic wastewater (WW) as a source of energy and raw materials, a concept consisting of chemical, physical, and biological steps has been set up as a pilot project in WWTP Büsnau, Stuttgart, Germany. The key part of the entire process is based on the use of advanced microsieving (MS) to eliminate remaining particulate organic carbon (POC) (mg/L) from the effluent of the primary sedimentation tank (PST). Therefore, in the primary stages of this project, it was necessary to have a broad vision and a true understanding of the particle size distribution (PSD) of municipal WW. As a novel approach, in the present study, the conventional PSD method was optimized by implementing certain modifications, and the tests were conducted in situ. The modified PSD analyses facilitated in-depth investigations of solid–liquid separation at WWTPs and showed that drying samples in the oven can result in a 20% to 30% deviation in the POC (mg/L) removal results. In addition, the idea of the substitution of PSTs with an MS was supported by the results of this study. It was determined that an MS with a pore size of 45 µm to 63 µm can provide the same elimination efficiency as a PST. Another significant outcome of this study was the introduction of suitable mesh sizes for the MS which were coupled with PST in order to extract the maximum amount of POC (mg/L) from the municipal WWTPs without the addition of any chemicals. The results revealed that up to 90% of the TSS (mg/L) and 70% of the COD (mg/L) can be removed if an MS with a mesh size between 4 µm and 20 µm is coupled with a PST. [ABSTRACT FROM AUTHOR]

This paper provides an overview and demonstration of emerging float-based methods for quantifying gross primary production (GPP) and net community production (NCP) using Biogeochemical-Argo (BGC-Argo) float data. Recent publications have described GPP methods that are based on the detection of diurnal oscillations in upper ocean oxygen or particulate organic carbon concentrations using single profilers or a composite of BGC-Argo floats. NCP methods rely on budget calculations to partition observed tracer variations into physical or biological processes occurring over timescales greater than one day. Presently, multi-year NCP time-series are feasible at near-weekly resolution, using consecutive or simultaneous float deployments at local scales. Results, however, are sensitive to the choice of tracer used in the budget calculations and uncertainties in the budget parametrizations employed across different NCP approaches. Decadal, basin-wide GPP calculations are currently achievable using data compiled from the entire BGC-Argo array, but finer spatial and temporal resolution requires more float deployments to construct diurnal tracer curves. A projected, global BGC-Argo array of 1000 floats should be sufficient to attain annual GPP estimates at 10-degree latitudinal resolution, if floats profile at off-integer intervals (e.g., 5.2 or 10.2 days). Addressing the current limitations of float-based methods should enable enhanced spatial and temporal coverage of marine GPP and NCP measurements, facilitating global-scale determinations of the carbon export potential, training of satellite primary production algorithms, and evaluations of biogeochemical numerical models. [ABSTRACT FROM AUTHOR]

The paper presents new data on concentrations and fluxes of organic carbon, iron, and manganese in waters of the mouth area of the Northern Dvina River. The work was conducted within the project "Northern Dvina River Marginal Filter Observatory" from May 2015 to May 2019 with monthly collection of water samples. Systematic determinations of the concentrations of the main carrier elements of many trace elements in dissolved and particulate forms were used to establish the average weighted of Corg, Fe, and Mn concentrations. The results of 4 years of systematic investigations established the main regularities of seasonal variations of dissolved and particulate forms of element concentrations and the relationships between. Significant variations were observed not only between concentrations but also between fluxes of elements in both forms. However, more than half the annual fluxes of all elements in all years studied was transported to the sea in the spring flood period. The results also demonstrated significant variations between element concentrations and their fluxes in different years. This is unsurprising, since even during the 4 years of investigations, the difference between water runoff and SPM fluxes in different years was up to, respectively, 1.4 and 2.6 times. [ABSTRACT FROM AUTHOR]

The ocean's biological carbon pump (BCP) plays a major role in the global carbon cycle. A fraction of the photosynthetically fixed organic carbon produced in surface waters is exported below the sunlit layer as settling particles (e.g., marine snow). Since the seminal works on the BCP, global estimates of the global strength of the BCP have improved but large uncertainties remain (from 5 to 20 GtCyr-1 exported below the euphotic zone or mixed-layer depth). The 234Th technique is widely used to measure the downward export of particulate organic carbon (POC). This technique has the advantage of allowing a downward flux to be determined by integrating the deficit of 234Th in the upper water column and coupling it to the POC/234Th ratio in sinking particles. However, the factors controlling the regional, temporal, and depth variations of POC/234Th ratios are poorly understood. We present a database of 9318 measurements of the POC/234Th ratio in the ocean, from the surface down to >5500 m , sampled on three size fractions (∼>0.7 µm , ∼1 –50 µm , ∼>50 µm), collected with in situ pumps and bottles, and also from bulk particles collected with sediment traps. The dataset is archived in the data repository PANGAEA® under 10.1594/PANGAEA.911424 (Puigcorbé, 2019). The samples presented in this dataset were collected between 1989 and 2018, and the data have been obtained from published papers and open datasets available online. Unpublished data have also been included. Multiple measurements can be found in most of the open ocean provinces. However, there is an uneven distribution of the data, with some areas highly sampled (e.g., China Sea, Bermuda Atlantic Time Series station) compared to some others that are not well represented, such as the southeastern Atlantic, the south Pacific, and the south Indian oceans. Some coastal areas, although in a much smaller number, are also included in this global compilation. Globally, based on different depth horizons and climate zones, the median POC/234Th ratios have a wide range, from 0.6 to 18 µmoldpm-1. [ABSTRACT FROM AUTHOR]

This paper applies new information concerning the process blank for radiocarbon analysis of dissolved organic carbon using UV-oxidation and subsequent accelerator mass spectrometry analysis. Recent analyses at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility show that reported values for such samples should be updated to reflect a process blank of 22 ± 6 micrograms of carbon with a fraction modern of 0.3 ± 0.2. The effects of this blank upon δ13C were also assessed and found to be generally less than 0.2‰. While this process blank does not change interpretations of stable carbon isotope results, it does affect interpretations of carbon cycling in Lake Superior, with the lake's bulk dissolved organic carbon (Bulk DOC, <0.7 µm), initial DOC (Init DOC, <0.2 μm) and low molecular weight DOC (LMW DOC, <1000 kDa) appearing more enriched in bomb radiocarbon than previously reported. This paper also applies a previously published process blank to particulate organic carbon data, and this application generally, but not always, leads to more enriched Δ14C values. [ABSTRACT FROM AUTHOR]

We present two new intermetalloid cluster compounds [(nBu3P)AuGe9(Hyp)2Au(PnBu3)]2 (1) and [Au(iPr2POC6H4OPiPr2)AuGe9(Hyp)2]2 (2) which are obtained from the reaction of KGe9(Hyp)3 (Hyp = Si(SiMe3)3) with the respective Au(I) phosphine precursors. The products are characterized via X-ray crystal structure analysis and the reaction course is analysed via NMR spectroscopy. We also show that in the resulting compound 1 the hypersilyl substituents can be reintroduced via the reaction with Hyp–Cl to obtain nBu3PAuGe9(Hyp)3. [ABSTRACT FROM AUTHOR]

We investigated assessments of calorie production and energy efficiencies of phytoplankton in Gwangyang, Jaran, and Geoje-Hansan bays in southern Korea, based on seasonal field measurements data for particulate organic carbon (POC), macromolecular compositions, calorie contents, and primary production. Our findings revealed that Geoje-Hansan Bay consistently exhibits higher POC concentrations compared to Gwangyang and Jaran bays, except during the summer season. The observed seasonal variations in POC concentrations and primary productions indicated distinct factors influencing POC distribution among the bays, which varies with the seasons. Macromolecular compositions displayed notable patterns, with Gwangyang Bay exhibiting pronounced seasonal variations, Jaran and Geoje-Hansan bays showing stable carbohydrate (CHO) dominance, and Gwangyang Bay displaying protein (PRT) dominance influenced by river-borne nutrients. Analysis of calorie content revealed that Geoje-Hansan Bay exhibited the highest calorie content, suggesting a more favorable physiological state of phytoplankton compared to Gwangyang and Jaran bays. Estimations of annual primary production and calorie production demonstrated regional variations, with Geoje-Hansan Bay having the highest values followed by Jaran Bay and Gwangyang Bay. These differences in primary production and calorie production reflect the diverse ecological conditions and nutrient availability specific to each bay. Interestingly, Gwangyang Bay demonstrated the highest energy efficiency, producing more calories per unit of carbon compared to the other two bays, potentially due to the influence of different dominant phytoplankton communities. This study enhances our understanding of ecosystem dynamics and ecological characteristics among the three bays, emphasizing the importance of considering seasonal variations and specific bay characteristics in investigating biogeochemical processes, energy flow, and ecosystem functioning. The findings contribute valuable insights for the sustainable management of coastal ecosystems and aquaculture practices. [ABSTRACT FROM AUTHOR]

The sediment biogeochemistry of phosphorus (P) and biogenic silica (BSi) in the southern South China Sea shelf (SSCS) is inadequate understood. Here, we examine the spatial distributions of P species and BSi in surface sediments across the Sunda Shelf and explore their relationships with satellite data of sea surface chlorophyll-a (Chla), suspended particulate matter (SPM), particulate organic carbon, particulate inorganic carbon, primary production (PP), and phytoplankton functional types. The total sediment P (TSP), in the range from 283.94 to 579.94 mg/g dry sediment, was dominated by inorganic P with higher levels in stations outside the Lupar and Saribas estuaries. The TSP was composed of seven different P species including Ca-IP and Ca-OP (58%), Detr-P (15%), Exch-P (11%), Fe-IP (10%), Ref-P (4%) and Ads-IP (2%) based on a sequential extraction method. The concentrations of various sediment P species were found significantly correlated with satellite climatological SPM, diatom biomass, and monthly climatological pico-PP revealing the importance of biological production for the sediment P storage, whereas the sediment BSi concentration showed no correlations with any of the above satellite products. An elevated R2 value in the regression of BSi with the in-situ depth-integrated Chla points to the need of developing satellite algorithms with vertical profiles from space. Finally, we argue that future studies of the SSCS sediment biogeochemistry may be benefited from data of hyperspectral and geostationary satellites. [ABSTRACT FROM AUTHOR]

Crystallization of alloys from a molten state is a fundamental process underpinning metallurgy. Here the direct imaging of an intermetallic precipitation reaction at equilibrium in a liquid‐metal environment is demonstrated. It is shown that the outer layers of a solidified intermetallic are surprisingly unstable to the depths of several nanometers, fluctuating between a crystalline and a liquid state. This effect, referred to herein as crystal interface liquefaction, is observed at remarkably low temperatures and results in highly unstable crystal interfaces at temperatures exceeding 200 K below the bulk melting point of the solid. In general, any liquefaction process would occur at or close to the formal melting point of a solid, thus differentiating the observed liquefaction phenomenon from other processes such as surface pre‐melting or conventional bulk melting. Crystal interface liquefaction is observed in a variety of binary alloy systems and as such, the findings may impact the understanding of crystallization and solidification processes in metallic systems and alloys more generally. [ABSTRACT FROM AUTHOR]

Forestation is a common measure to control erosion-induced soil and carbon (C) loss, but the effect can vary substantially between different types of forest. Here, we measured event-based runoff, soil, dissolved organic carbon (DOC), particulate organic carbon (POC) and total C loss with runoff plots (20 m × 5 m) in a broad-leaved and a coniferous forest in subtropical China and explored their relationships with rainfall amount, average intensity, maximum 5-min intensity and rainfall erosivity. The broad-leaved forest had a denser canopy but sparse understory vegetation while the coniferous forest had a relatively open canopy but dense understory vegetation. The results showed that runoff, soil, DOC, POC and total C losses were all significantly higher in the broad-leaved forest than the coniferous forest despite the potentially higher canopy interception associated with the greater leaf area index of the broad-leaved forest. The mean runoff in the broad-leaved forest was 3.03 ± 0.20 m3 ha−1 event−1 (mean ± standard error) and 12.49 ± 0.18 m3 ha−1 event−1 in the coniferous forest. The mean soil, DOC, POC and total C loss (kg ha−1 event−1) was 1.12 ± 0.16, 0.045 ± 0.003, 0.118 ± 0.016 and 0.163 ± 0.017, respectively, in the broad-leaved forest and 0.66 ± 0.09, 0.020 ± 0.002, 0.060 ± 0.009 and 0.081 ± 0.010, respectively, in the coniferous forest. Runoff and DOC losses were driven by rainfall in two forests, but the key rainfall characteristic driving soil, POC and total C losses was different in the broad-leaved forest from that in the coniferous forest due to their different understory patterns. Soil, POC and total C losses were mostly driven by rainfall amount in the broad-leaved forest but by EI30 in the conifer forest. Our findings highlight that the response of erosion-induced carbon loss to rainfall characteristics differs between different forest types of the same age but contrasting overstory and understory vegetation covers. Moreover, our study underscores the overlooked significance of understory vegetation in regulating these effects. Thus, we call for the inclusion of understory vegetation in the modeling of soil and carbon erosion in forest ecosystems. [ABSTRACT FROM AUTHOR]

We use observations from the Southern Ocean (SO) biogeochemical profiling float array to quantify the meridional pattern of particle export efficiency (PEeff) during the austral productive season. Float estimates reveal a pronounced latitudinal gradient of PEeff, which is quantitatively supported by a compilation of existing ship‐based measurements. Relying on complementary float‐based estimates of distinct carbon pools produced through biological activity, we find that PEeff peaks near the region of maximum particulate inorganic carbon sinking flux in the polar antarctic zone, where net primary production (NPP) is the lowest. Regions characterized by intermediate NPP and low PEeff, primarily in the subtropical and seasonal ice zones, are generally associated with a higher fraction of dissolved organic carbon production. Our study reveals the critical role of distinct biogenic carbon pool production in driving the latitudinal pattern of PEeff in the SO. Plain Language Summary: Microbial organisms in seawater transform carbon dioxide into different types of carbon through photosynthesis and food web cycling. These carbon types include particulate and dissolved phases, with particles being more efficiently transferred out of the sunlit ocean via gravitational sinking. The ratio of sinking particulate organic carbon to total organic carbon production, commonly referred to as the particle export efficiency, is a metric used to describe how efficiently carbon moves from the surface to the deep ocean. Using observations from a large array of robots in the Southern Ocean, we find that the different types of biogenic carbon produced control the latitudinal gradient in particle export efficiency, which is highest in regions where particulate inorganic carbon export is greatest, even when photosynthetically fixed carbon is minimal. In other areas where phytoplankton carbon production is moderate but largely comprised of dissolved organic carbon, the particle export efficiency is lower. Key Points: Meridional pattern of particle export efficiency (PEeff) estimated from BGC‐Argo aligns with ship‐based observations in the Southern OceanLow PEeff in subtropical and ice‐covered regions and high PEeff in subpolar regions is linked to the biogenic carbon pools producedMost global models struggle to reproduce the meridional pattern of PEeff in the Southern Ocean [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) persistence is predominantly governed by mineral protection, consequently, soil mineral-associated (MAOC) and particulate organic carbon (POC) turnovers have different impacts on the vulnerability of SOC to climate change. Here, we generate the global MAOC and POC maps using 8341 observations and then infer the turnover times of MAOC and POC by a data-model integration approach. Global MAOC and POC storages are 975 964 987 Pg C (mean with 5% and 95% quantiles) and 330 323 337 Pg C, while global mean MAOC and POC turnover times are 129 45 383 yr and 23 5 82 yr in the top meter, respectively. Climate warming-induced acceleration of MAOC and POC decomposition is greater in subsoil than that in topsoil. Overall, the global atlas of MAOC and POC turnover, together with the global distributions of MAOC and POC stocks, provide a benchmark for Earth system models to diagnose SOC-climate change feedback. Separating soil organic carbon into mineral-associated and particulate organic carbon enables a more accurate prediction of soil vulnerability to climate change. The authors generate the global atlas of stocks and turnover times of these two fractions. [ABSTRACT FROM AUTHOR]

Based on on-site survey data from 26 stations in the surface seawater of Zhanjiang Bay in April (spring), July (summer), September (autumn), and December (winter) of 2017, the spatial distribution characteristics of chlorophyll a (Chl a) and nutrients in the surface seawater of Zhanjiang Bay in different seasons were analyzed, and the regulatory mechanism of chlorophyll a spatiotemporal changes was discussed. The results showed that the Chl a concentrations in the surface water of Zhanjiang Bay are 0.44–37.43 mg/L, and are highest in summer and lowest in spring (summer: 11.6 µg/L; winter: 11.5 µg/L; autumn: 10.7 µg/L; spring: 1.8 µg/L). The spatial distribution of surface seawater Chl a in different seasons shows an opposite trend to the spatial distribution of nutrients. The study revealed that the low Chl a concentration in spring is mainly limited by SiO3-Si, while the high Chl a concentration in winter is closely related to climate conditions and coastal currents. This study suggests that based on the influence of monsoon climate and land rainfall erosion, the particulate organic carbon (POC) in Zhanjiang Bay in spring and summer is derived from land-based inputs, while in autumn and winter, the POC in the surface water of Zhanjiang Bay is mainly derived from in situ phytoplankton production. The dominant factors affecting the distribution of Chl a in the surface water of Zhanjiang Bay vary in different seasons, and are comprehensively influenced by terrestrial nutrient transport, artificial aquaculture, climate conditions, hydrodynamic conditions in the bay, and the coastal current of western Guangdong outside of the bay. The results of this study can provide scientific basis for improving the environment of Zhanjiang bay. [ABSTRACT FROM AUTHOR]

The hydrological and biogeochemical properties of the hyporheic zone in stream and riverine ecosystems have been extensively studied over the past two decades. Although it is widely acknowledged that sediment heterogeneity can influence biogeochemical reactions, little effort has been made to understand the role of heterogeneity on the spatiotemporal variability of riverbed redox conditions under changing flow dynamics at different timescales. Here we integrate a mechanistic model and field data to demonstrate that heterogeneity in permeability plays a vital role in modulating sediment redox conditions at both seasonal (annual) and event (daily‐to‐weekly) timescales, whereas heterogeneity in particulate organic carbon (POC) content only has a comparable influence on redox conditions at the seasonal timescale. These findings underscore the importance of accurately characterizing sediment heterogeneity, in terms of permeability and POC content, in quantifying biogeochemical dynamics in the riverbed and hyporheic zones of riverine ecosystems. Plain Language Summary: The redox condition of riverbed sediments is subject to the combined influence of hydrologic exchange flow and biogeochemical processes and is important for regulating the functioning of riverine ecosystems. Current understanding of the spatiotemporal pattern of sediment redox conditions especially with heterogeneity in consideration is limited, partially due to the lack of measurements and quantitative models. In this study, we integrate a mechanistic model and field data to reveal the role of sediment heterogeneity in controlling the redox condition under dynamic flow conditions. We demonstrate that heterogeneity in permeability modulates sediment redox condition at both seasonal and event timescales, and heterogeneity in particulate organic carbon is most prominent over multi‐month time intervals that reflect the balance between particulate organic carbon (POC) metabolism and time‐integrated oxygen influx. These findings highlight the importance of accurate characterization of sediment heterogeneity in both permeability and POC for predicting the dynamic redox shifts in riverbed sediments. Key Points: A reactive transport model was developed to quantify the impact of heterogeneity in permeability and particulate organic carbon (POC) concentration on sediment redox conditionsHeterogeneity in permeability controls sediment redox conditions at both seasonal (annual) and event (daily‐to‐weekly) timescalesThe effects of heterogeneity in POC occur over the monthly timescale, reflecting a balance between POC metabolism and the influx of oxygen [ABSTRACT FROM AUTHOR]

Coastal hypoxia, driven by remineralization of chlorophyllic particulate organic matter (POM) in dark environments, poses a threat to deep estuarine and shelf ecosystems. To better understand the fate of POM along a depth gradient, we investigated the degradation of chloropigments, particulate organic carbon (POC), and nitrogen (PON) across the water column in the St. Lawrence Estuary, one of the largest and deepest estuarine system in the world that is facing strong persistent and increasing hypoxia. Our objectives were to establish causal relationships among suspended POM descriptors and assess the potential of a chlorophyll-based degradation index, known as the chlorin index (CI), in evaluating OM degradation within the water column. The CI, ranging from 0.2 for pure chlorophyll to almost 1 for highly degraded pigments, was initially developed for uses in the sediments. Water samples from multiple depths were collected, characterized, and statistically analyzed with a combination of variation partitioning, non-linear regressions and piecewise structural equation modeling (pSEM). We found that the combined influence of chloropigments and depth explained 84.0% of POC and 90.0% of PON variations; the pure fraction attributed to chloropigments accounted for 73.4% and 75.6% (R2 adj, both with p< 0.001), respectively. The decline of chloropigments, PON, and POC with increasing depth was reflected by the concomitant increase in CI, whose rate decreases as particles sink resulting in reduced degradation due to less labile organic matter. The pSEM causal model indicated that CI increased with depth and POC concentration, while it decreased in the presence of elevated PON concentrations, known for their high reactivity. The direct effect of depth on CI could be linked to the distinct water column properties influencing particle residence time and thus the degradation potential by biotic and abiotic factors. Finally, CI explained 86% (R2) of the apparent oxygen utilization highlighting the strong connection between POM degradation and hypoxia of deep coastal ecosystems. Our study underscores the utility of the chlorin index as a simple yet robust tool formonitoring OM degradation in the water column, particularly in the St. Lawrence Estuary. [ABSTRACT FROM AUTHOR]

Diesel particulate matter (DPM) is a common and well-known health hazard in the mining environment. The regulatory method for monitoring both the organic and elemental carbon (OC, EC) portions of DPM is a laboratory-based thermal-optical method with a typical turnaround time of one week. In order to evaluate exposure levels and take corrective action prior to overexposure, a portable real-time device capable of quantifying both OC and EC is needed. To that end, researchers from the National Institute for Occupational Safety and Health (NIOSH) designed and tested the feasibility of a device based on bandpass optical filters that target key infrared wavelengths associated with DPM and its spectroscopic baseline. The resulting device, referred to here as a non-dispersive infrared (NDIR) spectrometer could serve as the basis of a cost-effective, field-portable alternative to the laboratory thermal-optical method. The limits of quantification (LOD) indicate that the NDIR spectrometer can quantify EC, OC, and TC provided they are present at 20, 37, and 46 μg/m3 or more, respectively. In the event that the NDIR spectrometer is integrated with a sampler and filter tape the LOD is estimated to be reduced to 13, 7, and 10 μg/m3 for EC, OC, and TC, respectively. These LOD estimates assume a face velocity of 59 cm/s and a sampling time of 30 min. [ABSTRACT FROM AUTHOR]