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The intensive energy demands associated with solvent regeneration and CO2 release in current direct air capture (DAC) technologies makes their deployment at the massive scales (GtCO2/year) required to positively impact the climate economically unfeasible. This challenge underscores the critical need to develop new DAC processes with significantly reduced energy costs. Recently, we developed a new approach to photochemically drive efficient release of CO2 through an intermolecular proton transfer reaction by exploiting the unique properties of an indazole metastable‐state photoacid (mPAH), opening a new avenue towards energy efficient on‐demand CO2 release and solvent regeneration using abundant solar energy instead of heat. In this Concept Article, we will describe the principle of our photochemically‐driven CO2 release approach for solvent‐based DAC systems, discuss the essential prerequisites and conditions to realize this cyclable CO2 release chemistry under ambient conditions. We outline the key findings of our approach, discuss the latest developments from other research laboratories, detail approaches used to monitor DAC systems in situ, and highlight experimental procedures for validating its feasibility. We conclude with a summary and outlook into the immediate challenges that must be addressed in order to fully exploit this novel photochemically‐driven approach to DAC solvent regeneration. [ABSTRACT FROM AUTHOR]

The consequences of warming-induced 'shrubification' on Arctic soil carbon storage are receiving increased attention, as the majority of ecosystem carbon in these systems is stored in soils. Soil carbon cycles in these ecosystems are usually tightly coupled with nitrogen availability. Soil microbial responses to 'shrubification' may depend on the traits of the shrub species that increase in response to warming. Increase in deciduous shrubs such as Betula nana likely promotes a loss of soil carbon, whereas the opposite may be true if evergreen shrubs such as Empetrum hermaphroditum increase. We analyzed soil organic matter stocks and 13C NMR fractions, microbial CO2 respiration, biomass, extracellular enzyme activities (EEAs), and their association with shrub density in northern Sweden after 20 years of experimental warming using open top chambers (OTCs). Our study sites were located in a tundra heath that stores high soil carbon quantities and where the OTCs had increased deciduous shrubs, and in a mountain birch forest that stores lower soil carbon quantities and where the OTCs had increased evergreen shrubs. We predicted that organic matter stocks should be lower and respiration and EEAs higher inside the OTCs than untreated plots in the tundra, whereas no effect should be detected in the forest. Soil organic matter stocks and 13C NMR fractions remained unaffected at both sites. When expressed as per gram microbial biomass, respiration and EEAs for carbohydrate and chitin degradation were higher inside the OTCs, and contrasting our prediction, this effect was stronger in the forest. Unexpectedly, the OTCs also led to a substantially lower microbial biomass carbon and nitrogen irrespective of habitat. The decline in the microbial biomass counteracted increased activities resulting in no effect of the OTCs on respiration and a lower phenol oxidase activity per gram soil. Microbial biomass nitrogen correlated negatively with evergreen shrub density at both sites, indicating that 'shrubification' may have intensified nutrient competition between plants and soil microorganisms. Nutrient limitation could also underlie increased respiration per gram microbial biomass through limiting C assimilation into biomass. We hypothesize that increasing nutrient immobilization into long-lived evergreen shrubs could over time induce microbial nutrient limitation that contributes to a stability of accumulated soil organic matter stocks under climate warming. [ABSTRACT FROM AUTHOR]

Large Igneous Provinces (LIPs) facilitate massive transfers of CO2 and other volatiles from the mantle to atmosphere, contributing to past global warming and environmental disruption. However, the scale and evolution of magmatic CO2 fluxes during these events remain uncertain due to the tendency of CO2 to degas deep in magmatic systems. Here we estimate LIP CO2 using an approach based on an observed correlation between gas CO2/S ratios and trace elements in volcanic rocks. We apply this method to a compilation of published geochemical data for tholeiitic LIP lavas and to a new major and trace element dataset for alkaline rocks from the Siberian Traps. Our results indicate that CO2/S and therefore CO2 in tholeiitic and alkaline magma suites from LIPs span 1–2 orders of magnitude, emphasizing that changing CO2 concentrations can combine with magma flux to drive strong variations in CO2 release through the evolution of LIP magmatism.

One of the grand challenges underlying current direct air capture (DAC) technologies relates to the intensive energy cost for sorbent regeneration and CO2 release, making the massive scale (GtCO2/year) deployment required to have a positive impact on climate change economically unfeasible. This challenge underscores the critical need to develop new DAC processes with substantially reduced regeneration energies. Here, we report a photochemically‐driven approach for CO2 release by exploiting the unique properties of an indazole metastable‐state photoacid (mPAH). Our measurements on simulated and amino acid‐based DAC systems revealed the potential of mPAH to be used for CO2 release cycles by regulating pH changes and associated isomers driven by light. Upon irradiating with moderate intensity light, a ≈55 % and ≈68 % to ≈78 % conversion of total inorganic carbon to CO2 was found for the simulated and amino acid‐based DAC systems, respectively. Our results confirm the feasibility of on‐demand CO2 release under ambient conditions using light instead of heat, thereby providing an energy efficient pathway for the regeneration of DAC sorbents. [ABSTRACT FROM AUTHOR]

In this study, CO2 free expansion from high‐pressure tanks is studied in a transient state while considering the influence of different phenomena—that is, viscous heating, phase transition (solid/liquid/vapour phase), and the Joule–Thomson effect—in an initially supersonic flow. This investigation is performed using computational fluid dynamics (CFD) techniques, comparing the obtained results with some experimental data of the literature with a maximum discrepancy of around 8.5%. In particular, for the first time from the literature, it is observed that, according to the velocity evolution at the outlet, the discharge process is conveniently divided into three here‐defined stages: (1) shocking flow, where pressure abruptly decreases with time and flow becomes supersonic, this leading to the condensation of part of CO2; (2) transition flow, characterized by a sort of constant pressure time trend; and (3) flashing flow, where pressure decreases less abruptly following an asymptotic pattern up to the atmospheric one and flow becomes subsonic. Furthermore, non‐equilibrium condensation occurring in the tank, tube, and outlet is observed, finding that the minimum temperature reached by the fluid is around 235 K (−38°C). As well, the non‐equilibrium condensation is taken into account in order to give an indication of the amount of liquid CO2 leaving the outlet in the form of high‐speed jet, which can be a serious danger for personnel and surrounding installations. Moreover, we observe an important effect of viscous heating in the early‐stage expansion for a relatively short time range, within which the temperature in the tube experiences an abrupt increase of around 210 K (from 170 to 380 K). The same effect in the external room creates a convection flow, pushing CO2 towards the top. The results of the present work can be used for health, safety, and environment (HSE) management purposes and for a more precise process design related to CO2 storage and sequestration. [ABSTRACT FROM AUTHOR]

Carbon emission is the main cause of carbon loss during composting. This study investigated the effect of bamboo biochar addition to compost on carbon dioxide (CO2) release and fixation through metagenomics sequencing. The results showed that the addition of biochar enriched the relative abundance of ribulose-1,5-diphosphate carboxylase/oxygenase (RuBisCO) gene by 13.22%, improving the diversity of carbon-fixing microbiota. In addition, biochar also inhibited the relative abundances of pyruvate dehydrogenase (PDH), isocitrate dehydrogenase (IDH), and alpha-ketoglutarate dehydrogenase (A_KGD) at the late stage of composting, thereby reducing the CO2 release by 16.77%. Bamboo biochar also decreased the abundance of Methyl coenzyme-M reductase (MCR), which in turn reduced methane (CH4) release. Redundancy analysis (RDA) showed that Proteobacteria was the dominant phylum in the compost system during the cooling and maturity periods, which dominated the release of CO2 and was positively correlated with PDH, IDH, and A_KGD (p < 0.01). In addition, RubisCO was negatively correlated with organic matter (OM), CO2, CH4 (p < 0.01). Taken together, biochar can inhibit the activity of CO2-releasing microorganisms, thereby reducing carbon loss in composting. [ABSTRACT FROM AUTHOR]

Chemical weathering plays an important role in modulating Earth's climate. However, chemical weathering is usually influenced by multiple factors simultaneously (e.g., climate, topography and lithology), and it is difficult to understand how these variables modulate the effect of chemical weathering on atmospheric p CO 2. In this study, we collected and analyzed water chemistry and multiple isotopes (δ34S SO4 , δ18O SO4 and δ18O H2O) in the Bailong River catchment to decipher how these variables influence chemical weathering and its effect on atmospheric p CO 2. We used the Monte Carlo inversion model to partition the sources of major cations and SO 4 2 − , and the results reveal that carbonate weathering is the dominant source contributing cations in river. Sulfide oxidation is the most important source for SO 4 2 − and a supply-limited process that is highly dependent on slope. We thus think slope is main factor modulating the effect of chemical weathering on atmospheric p CO 2. Steep slope increases sulfide oxidation rate by elevating erosion, resulting in chemical weathering acting as a CO 2 source. In contrast, gentle slope could facilitate a thick regolith that contributes long-term silicate weathering and limits sulfide oxidation, resulting in chemical weathering acting as a CO 2 sink. And it has been found that the influence of temperature on chemical weathering becomes progressively pronounced with increasing altitude. This study investigated sulfide weathering in eroding Qinghai-Tibet Plateau, highlighting the geomorphologically controlled CO 2 effects of chemical weathering. • There is significant spatial heterogeneity in climate, topography and lithology, influencing rock weathering in the Bailong River. • Sulfide oxidation is the most important source for SO 4 2 − , and the contribution of sulfide oxidation to SO 4 2 − is highly dependent on slope. • Slope is the main factor modulating the effect of rock weathering on atmospheric p CO 2. • The effect of temperature on rock weathering becomes progressively more pronounced with increasing altitude. [ABSTRACT FROM AUTHOR]

Fertilizer application is key for plant yield promotion, but also has side effects on microbes, organic carbon storage and aggregate size distributions. However, links between these factors and especially how different amounts of organic and mineral fertilizers affect microbial-driven CO 2 release at the aggregate scale remains largely unknown. We quantified carbon decomposition gene abundance and diversity, microbial residual carbon and CO 2 release from the labile or stable carbon pools in three soil aggregate size fractions in organic and mineral fertilized soil. Compared to mineral fertilizer, organic fertilizer increased abundances of carbon decomposition genes, extracellular enzyme activities, microbial residual carbon and CO 2 released from the labile carbon pool, but decreased CO 2 released from the stable carbon pool in microaggregates. Likewise, organic fertilizer increased the proportion of macroaggregates, microbial residual carbon and CO 2 released from the labile carbon pool, but had no effect on carbon degradation gene abundance and extracellular carbon enzyme activity. Taken together, we illustrate that organic fertilizer application decreases CO 2 release via increasing the proportion of macroaggregates, leading to increased carbon storage that can provide a means to lessening atmospheric carbon. [Display omitted] • Organic fertilizer decreases CO 2 release via increasing macroaggregates fractions • Organic fertilizer increased carbon degradation gene abundances in microaggregates • Organic fertilizer decreased CO 2 release from the stable carbon pool in three aggregate fractions [ABSTRACT FROM AUTHOR]

The remediation of open-cast post-mining soil remains a big challenge. Here, the post-mining soils are considered from the viewpoints of CO2 emission and carbon sequestration. We investigated the dynamic of C stock in two different post-mining areas, i.e., the limestone post-mining soil remediated with embankment (S1), and the lignite post-mining soil remediated with sewage sludge (S2). Post-mining soils under four different remediation stages were used. The study was conducted in the spring of 2021 and 2022. The aim of the study was to assess the C sequestration in sewage sludge amended and non-amended post-mining soils at differently advanced remediation techniques. We noticed an increase in or stabilization of SOC in the S1. The stabilization of SOC was observed for the soil with a higher remediation age (S1C, S1D). The remediation of the S2 resulted in the increase in SOC among the soil remediation age. For both soils, we noticed a negative CO2 emission from the soil under remediation, and the net CO2 emission rate (NCER) further decreased after one year. A positive C feedback of both remediation techniques was shown to reflect lower active carbon (POXC). We also noticed an increase in nutrient content (K, Mg), and a decrease in heavy metals content after 1 year. Such a positive relationship between the remediation of post-mining soils and C sequestration indicates a step towards climate change mitigation. [ABSTRACT FROM AUTHOR]

Phytoremediation is a green, cost-effective alternative to established soil remediation technologies. The recent bacterial-mycorrhizal revolution in combination with plants has resulted in significant advances in our knowledge of metal removal in polluted soils. However, depending on the biomass and size of the roots, each plant differs in its capacity to remove heavy metals. The study's objective was to study the effects of bacteria, mycorrhiza, papyrus, and CO2 release on lead (Pb) and cadmium (Cd) removal from the soil. Six different combinations (mycorrhiza, Bacillus 10 mL, Bacillus 100 mL, mycorrhiza + Bacillus 10 mL, mycorrhiza + Bacillus 100 mL, and control) were used in the experiment. The results showed that the combination of the mycorrhiza with bacillus 100 mL showed more profound increases in CO2 release and polysaccharide content (2.84 mg CO2 g−1 dry soil, 0.90 mg) respectively. More importantly, the highest concentrations of Cd and Pb were found in the roots of mycorrhiza + Bacillus 100 mL (18.26 mg kg−1 and 155.22 mg kg−1, respectively), implying that microbes played a concrete role in the phytoextraction process. The highest values of the translocation factor (TF) and biological accumulation factor (BAF) for Cd were found at Bacillus 100 mL (3.99) and (75.54), respectively, suggesting efficient translocation and excessive Cd accumulation in the plant. For Pb, Bacillus 100 mL and mycorrhiza + Bacillus 100 mL had the highest TF and BAF, which were 0.49 and 6.08 respectively. In conclusion, the removal of Cd and Pb was linked to the maximum bacterial cell density, mycorrhizal activity, and CO2 emission, resulting in unique phytoremediation in Pb–Cd contaminated papyrus rhizosphere soils. [ABSTRACT FROM AUTHOR]

Ornithine decarboxylase (ODC) catalyzes the decarboxylation of ornithine to produce putrescine, the first step in the metabolism of polyamines (putrescine, spermidine, and spermine), which are essential growth factors in eukaryotic cells. ODC is active as a homodimer and depends on pyridoxal 5'-phosphate (PLP) as a cofactor. An increase in the concentration of polyamines has been associated with carcinogenesis. Therefore, there is much interest in identifying inhibitors of this pathway as potential chemotherapeutic and chemopreventive agents. The best-known inhibitor of mammalian ODC is a-difluoromethylornithine (DFMO), a highly selective compound that alkylates Cys-360 (a residue of the ODC active site). Although DFMO was initially developed for the treatment of cancer, the World Health Organization recommends its use in combination with nifurtimox for the treatment of human African trypanosomiasis. Considering the importance of ODC as a promising target for the treatment of various types of cancer and other infectious diseases, choosing the right method for screening potential inhibitors can help to accelerate the discovery of new drugs. Several methods for the determination of ODC activity are found in the literature. Among these, we can mention analysis with radioactive markers, colorimetric assays using auxiliary enzymes to detectCO2 or H2O2 release, chromatographic separations with putrescine derivatization, mass spectrometry, and spectroscopic techniques. In this review, the main analysis methods used will be described, highlighting their advantages and disadvantages, as well as identifying the most promising methods for high-throughput screening. [ABSTRACT FROM AUTHOR]

The intensive energy demands associated with solvent regeneration and CO 2 release in current direct air capture (DAC) technologies makes their deployment at the massive scales (GtCO 2 /year) required to positively impact the climate economically unfeasible. This challenge underscores the critical need to develop new DAC processes with significantly reduced energy costs. Recently, we developed a new approach to photochemically drive efficient release of CO 2 through an intermolecular proton transfer reaction by exploiting the unique properties of an indazole metastable-state photoacid (mPAH), opening a new avenue towards energy efficient on-demand CO 2 release and solvent regeneration using abundant solar energy instead of heat. In this Concept Article, we will describe the principle of our photochemically-driven CO 2 release approach for solvent-based DAC systems, discuss the essential prerequisites and conditions to realize this cyclable CO 2 release chemistry under ambient conditions. We outline the key findings of our approach, discuss the latest developments from other research laboratories, detail approaches used to monitor DAC systems in situ, and highlight experimental procedures for validating its feasibility. We conclude with a summary and outlook into the immediate challenges that must be addressed in order to fully exploit this novel photochemically-driven approach to DAC solvent regeneration., (© 2024 Wiley-VCH GmbH.)

Dead organic matter (DOM), which consists of leaf litter, fine woody debris (FWD; <3 cm diameter), downed coarse woody debris (CWDlog), and standing or suspended coarse woody debris (CWDsnag), contributes to forest carbon cycling; however, few studies have considered effects of differences in DOM types on the stand‐scale estimates of carbon stocks of necromass and CO2 efflux (Rstand). This study investigated characteristics of necromass and Rstand in a subtropical forest in Okinawa Island, Japan, to quantify the effect of DOM type on total necromass, total Rstand, and estimate error of total necromass and Rstand. The CWDsnag accounted for the highest proportion (54%) of total necromass (1499.7 g C m−2), followed by CWDlog (24%), FWD (11%), and leaf litter (11%). Leaf litter accounted for the highest proportion (37%) of total Rstand (340.6 g C m−2 year−1), followed by CWDsnag (25%), CWDlog (20%), and FWD (17%). The CWDsnag was distributed locally with 173% coefficient of variation for necromass, which was twofold higher than those of leaf litter and FWD (72%–73%). The potential error in CWD accounted for 99% and 79% estimate error for total necromass and Rstand, respectively. For the estimates of CWDsnag and CWDlog necromass with the estimates error of <10% in this study area, sampling areas of ≥28,750 m2 and ≥2058–42,875 m2, respectively, were required. Our results showed that CWD considerably contributed to stand‐scale carbon stocks and efflux among aboveground DOM in this forest, resulting in a major source of errors in the stand‐scale estimates. [ABSTRACT FROM AUTHOR]

The stability of biochar in soil was an important property influencing biochar environmental effects, most studies attributed biochar stability to its intrinsic molecular structure, but few realized that biochar stability mainly depended on soil environmental factors. In this study, biochar was applied into five soils with distinct properties, and CO2 release was detected during a 28‐days incubation, double‐exponential model was used to fit CO2 cumulative release. Correlation analysis between basic properties of five soils and parameters of double‐exponential model was conducted to screen out crucial soil factors affecting biochar stability. Argi‐Udic Ferrosols soil, showing best performance among five soils on protecting biochar stability, was selected to simulate paddy‐upland rotation, exploring the influence of abrupt increase of soil moisture on biochar stability. Results showed that CO2 release from biochar had negative correlation with clay and Fe content of soil (correlation coefficient was −0.68 ~ −0.61 and −0.60 ~ −0.26), whereas had positive correlation with pH and Ca content of soil (correlation coefficient was 0.29 ~ 0.69 and 0.74 ~ 0.91). Abrupt increase of moisture resulted in labile‐C loss from biochar increased by 1.4 times. It implied that biochar stability was an ecological property, and acid soil, rich in clay and Fe contents and less in Ca content, was more favorable to maintain biochar stability. Results in this study were helpful to understand environmental chemistry behavior of biochar and better perform its soil environmental effects. [ABSTRACT FROM AUTHOR]

The remediation of open-cast post-mining soil remains a big challenge. Here, the post-mining soils are considered from the viewpoints of CO2 emission and carbon sequestration. We investigated the dynamic of C stock in two different post-mining areas, i.e., the limestone post-mining soil remediated with embankment (S1), and the lignite post-mining soil remediated with sewage sludge (S2). Post-mining soils under four different remediation stages were used. The study was conducted in the spring of 2021 and 2022. The aim of the study was to assess the C sequestration in sewage sludge amended and non-amended post-mining soils at differently advanced remediation techniques. We noticed an increase in or stabilization of SOC in the S1. The stabilization of SOC was observed for the soil with a higher remediation age (S1C, S1D). The remediation of the S2 resulted in the increase in SOC among the soil remediation age. For both soils, we noticed a negative CO2 emission from the soil under remediation, and the net CO2 emission rate (NCER) further decreased after one year. A positive C feedback of both remediation techniques was shown to reflect lower active carbon (POXC). We also noticed an increase in nutrient content (K, Mg), and a decrease in heavy metals content after 1 year. Such a positive relationship between the remediation of post-mining soils and C sequestration indicates a step towards climate change mitigation.

Packaging is one of the main factors of logistics. Its primary roles are protection, preservation, traceability, profitability, convenience / practicality and presentation, while its secondary roles are handling, containment (safety containers), identification, labelling and suitability. A wide range of regulatory measures, high standards and the correct handling of food in logistics processes ensure that food is delivered safely from the producer to the consumer. The essential role of packaging in logistics is to provide products with the necessary protection during storage and transport and to reduce costs. Packaging has a positive impact on product distribution and safety, particularly in the food industry, where it increases shelf life, facilitates transportation and helps to save costs. By carefully arranging and packaging the products in suitable packaging, the available space can be used optimally. This article presents the role of packaging in logistics processes such as transport, storage, loading and packaging of food with an explicit focus on sustainability. A case study shows the example of the overseas logistics chain of the avocado, a type of food with very high CO2 release and high water consumption. The status of the green logistics and further requirements for companies and consumers is demonstrated.

Mineralization rates of soil organic matter (SOM) decomposition in nonremediated and remediated oil-polluted soils and background soils from the main types of West Siberian middle-taiga ecosystems have been measured in laboratory experiments. The rates of SOM mineralization were measured by alkali absorption of CO2 released from wet soil samples at 20°C (basal respiration). Taking into account the linear character of the cumulative curves of CO2 release, the rates of SOM mineralization were estimated using the mineralization index K1, equal to the annual amount of CO2 released per 1 g dry soil. The K1 values varied from 0.123 to 1.578 mg CO2/g/day. The highest value was recorded in the background forest soil, while the lowest value in the oil-polluted peat soil with extremely high oil content (544 g/kg). The K1 values were negatively correlated with oil content (K = –0.57). The SOM mineralization rate in remediated oil-polluted peat soils varied from 0.31 to 0.85 mg CO2/g/day. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this work was to investigate the process of biodrying of municipal solid waste from the old landfill to preparing it for pyrolysis or gasification. New aspect of this research is biodrying of waste from old landfill. Biodrying of wastes was carried out at different aeration rates (7, 35, and 175 dm3/kg dry matter/d) at two temperatures (23 and 50 °C). The research was carried out in the laboratory bioreactors of special design (lysimeters), which simulated the conditions prevailing in the landfill. The optimal conditions for reduction of moisture in waste (63.2%) has been attained for the highest aeration rate (175 dm3/kg dry matter/d) and temperature equal to 50 °C. The final moisture content of the obtained biodried product was 23% w/w. In the bioreactor, in which the greatest reduction of moisture was obtained, the total amount of produced CO2 was 44.9 gC/kg dry matter, and the biodrying efficiency was equal to 0.89. During biodrying of wastes in optimal conditions, higher heating value of waste increased from 4.3 to 11.0 MJ/kg. As a result of the performed pyrolysis of biodried waste at 900 °C, char, oil, and gas were obtained the respective yields of 47, 32, and 21% w/w. The gas emerging in the gasification process was characterized by higher heating value equal to 11.3 MJ/m3. [ABSTRACT FROM AUTHOR]

This study aimed to analyze the bacteria population, the release of CO2, pH and organic-C and total-N in the process of compost made from manure and swamp grass. Treatment level consist of 100% manure (K100), 50% of manure + 50% swamp grass (K50R50), 25% of manure + 75% swamp grass (K25R75), and 10% of manure + 90% swamp grass (K10R90). The result of this study indicated the dynamic of different bacteria population on different composting materials by increasing of the composting time. The release of CO2 decrease on all treatment levels by increasing of the composting time. The pH value increased at all levels of treatment, except the composition of 100% manure. The best composition obtained by mixing of 10% manure and 90% swamp grass.

Minimally intrusive geophysical methods are required to monitor CO2 leakages from underground storage reservoirs. We investigate the impact of gaseous CO2 on both electrical conductivity and electrokinetic properties of two limestones during their drainage. These data are contrasted with measurements performed on one clay‐free sandstone. The initial NaCl brine concentrations before drainage (from 8.5 to 17.1 mMol/L) correspond to the limit between freshwater and slightly brackish water. These values are representative to saturated brine formations inside which CO2 can be stored. Using these water salinities, the surface conductivity of the samples represents less than 5% of the overall electrical conductivity. A CO2 release leads to an increase of the electrical conductivity of the rock during drainage in limestones and no change in sandstone. This increase in the electrical conductivity is due to the dissolution of calcite with the concomitant release of Ca2+ and HCO3− in the pore water. It is not due to the CO2 dissociation in the pore water in the pore pressure range 0–0.5 MPa and at a temperature of T = 20 °C. The measurements of the streaming potential show a substantial decrease of the streaming potential coupling coefficient and zeta potential magnitudes after a CO2 release in carbonates. This observation is explained by the increase of the ionic strength of the pore water in the course of the experiment. This change can be used, in turn, to determine calcite dissolution rates from the measurement of the electrokinetic properties. Key Points: The dissolution of calcite leads to a decrease of the magnitude of the streaming potential coupling coefficientThe pore water conductivity is dominated by the calcite dissolution in carbonatesCalcite dissolution rates calculated from streaming potential measurements are consistent with PHREEQC simulations [ABSTRACT FROM AUTHOR]

Abstract Humification plays a critical role in the environmental fate of organic wastes, and MnO 2 holds great promise for enhancing this reaction. However, the effects of MnO 2 on the enhancement of the humification reaction remain ambiguous. To better reveal the mechanism by which MnO 2 enhances the reaction and investigate the fate of the humification products, abiotic humification experiments were performed using increasing concentrations of dissolved organic matter (DOM) to a fixed amount of MnO 2. DOM was represented by model humic precursors consisting of catechol, glucose and glycine. The results indicate that the reduction of MnO 2 played a dominant role in the formation of fulvic-like acids (FLAs), and the subsequent reduction products, MnOOH and Mn(II), acted as catalysts in the formation of humic-like acids (HLAs). Moreover, CO 2 release occurred during the formation of FLAs, and a strong linear correlation between CO 2 release and the formation of FLAs was observed (p < 0.01), where 0.73–1.87 mg of CO 2 was released per mg dissolved organic carbon (DOC) FLAs. Furthermore, the concentration of MnO 2 had a pronounced influence on the product behavior, where a lower MnO 2 concentration decreased the quantity of FLAs produced. Graphical abstract Proposed oxidation catalysis mechanisms of MnO 2 and the related reduction products in the abiotic humification of organic matter. Unlabelled Image [ABSTRACT FROM AUTHOR]

Organic matter decomposition is a biochemical process with consequences affecting climate change and ecosystem productivity. Once decomposition begins, C is lost as CO 2 or sequestered into more recalcitrant carbon difficult to further degradation. As microbial respiration releases carbon dioxide into the atmosphere, microbes act as gatekeepers in the whole process. Microbial activities were found to be the second largest CO 2 emission source in the environment after human activities (industrialization), and research investigations suggest that this may have affected climate change over the past few decades. It is crucial to note that microbes are major contributors in the whole C cycle (decomposition, transformation, and stabilization). Therefore, imbalances in the C cycle might be causing changes in the entire carbon content of the ecosystem. The significance of microbes, especially soil bacteria in the terrestrial carbon cycle requires more attention. This review focuses on the factors that affect microorganism behavior during the breakdown of organic materials. The key factors affecting the microbial degradation processes are the quality of the input material, nitrogen, temperature, and moisture content. In this review, we suggest that to address global climate change and its effects on agricultural systems and vice versa, there is a need to double-up on efforts and conduct new research studies to further evaluate the potential of microbial communities to reduce their contribution to terrestrial carbon emission. [Display omitted] • Microbes are the player of climate and involved in transfer of C state in ecosystem. • Microorganisms are responsible for processing plant photosynthetic C inputs to soil. • The priming effect alters the microbial biomass turnover on C addition. • Bacteria easily degrade plant exudate while fungi breakdown more resistant compounds. • New model required for understanding of SOC dynamics driven by microbes & Nutrients. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Milk fermentation takes place in the presence of various micro‐organisms, producing a variety of dairy products. The oldest of them is kefir, which is usually produced by the fermentation of milk with kefir grains. Carbon dioxide (CO2), as one of the process products, also contributes to the characteristic flavor of kefir. The amount of CO2 generated during fermentation depends on bioprocessing conditions and may change, which is not desirable at the industrial level. RESULTS: In this study we developed a simplified mathematical model of CO2 release in the milk‐fermentation process. An intuitive approach based on superposition and experimental analysis was used for the modeling. The chemical system studied was considered as a two‐input (temperature, rotational frequency of the stirrer) one‐output (CO2 concentration) dynamic system. CONCLUSION: Based on an analysis of CO2 release transients in the case of non‐simultaneous stepwise changed input quantities, two differential equations were defined that describe the influence of the two input quantities on the output quantity. The simulation results were verified by experiments. The proposed model can be used for a comprehensive analysis of the process that is being studied and for the design and synthesis of advanced control systems, which will ensure a controlled CO2 release at the industrial level. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

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

The operation of the thoracic spiracular valves was analysed using anatomical and physiological techniques. Dense spiracular filter trichomes impede a diffusive gas exchange. However, the hinged posterior filter flap of the metathoracic spiracle (Sp2) opens passively during upstroke of the wings and closes by the suction of the subatmospheric tracheal pressure during the downstroke, which supports a unidirectional respiratory airflow. The action of the interior spiracular valve lids was recorded by photocell sensors oriented above the enlarged spiracles and projected onto the screen of a video camera. The thoracic spiracles opened much quicker (approximately 0.1 s) than they closed (1 s), suggesting that the spiracular muscles are openers, as confirmed by experimental induction of muscle contraction. Simultaneous photocell measurement revealed that the first and second thoracic spiracles act concordantly. At rest, the spiracles were mostly closed or only slightly open (<1%). During intermittent short flights, the valves opened wide at the start of the flight for a short time, and in many cases opened again after the flight ended. Often, the opening was wider after the flight ended than during the flight itself. During long spontaneous continuous flight phases (up to 2 h), the valves were only slightly open (<5%), widening shortly after transient increases of wing stroke intensity. It is an amazing paradox that the spiracles were only slightly open when the requirement for O2 was high during sustained flight. The advantage of generating sub-atmospheric pressure, supporting a unidirectional airflow with a PO2 increase above the resting level, is discussed. [ABSTRACT FROM AUTHOR]

One of the grand challenges underlying current direct air capture (DAC) technologies relates to the intensive energy cost for sorbent regeneration and CO 2 release, making the massive scale (GtCO 2 /year) deployment required to have a positive impact on climate change economically unfeasible. This challenge underscores the critical need to develop new DAC processes with substantially reduced regeneration energies. Here, we report a photochemically-driven approach for CO 2 release by exploiting the unique properties of an indazole metastable-state photoacid (mPAH). Our measurements on simulated and amino acid-based DAC systems revealed the potential of mPAH to be used for CO 2 release cycles by regulating pH changes and associated isomers driven by light. Upon irradiating with moderate intensity light, a ≈55 % and ≈68 % to ≈78 % conversion of total inorganic carbon to CO 2 was found for the simulated and amino acid-based DAC systems, respectively. Our results confirm the feasibility of on-demand CO 2 release under ambient conditions using light instead of heat, thereby providing an energy efficient pathway for the regeneration of DAC sorbents., (© 2023 Wiley-VCH GmbH.)

Carbonic anhydrases are mostly zinc metalloenzymes that catalyze the reversible hydration/dehydration of CO2/HCO3-. Previously, the X-ray crystal structures of CO2-bound holo (zinc-bound) and apo (zinc-free) human carbonic anhydrase IIs (hCA IIs) were captured at high resolution. Here, we present sequential timeframe structures of holo- [T = 0 s (CO2-bound), 50 s, 3 min, 10 min, 25 min, and 1 h] and apo-hCA IIs [T = 0 s, 50 s, 3 min, and 10 min] during the "slow" release of CO2. Two active site waters, WDW (deep water) and WDW' (this study), replace the vacated space created on CO2 release, and another water, WI (intermediate water), is seen to translocate to the proton wire position W1. In addition, on the rim of the active site pocket, a water W2' (this study), in close proximity to residue His64 and W2, gradually exits the active site, whereas His64 concurrently rotates from pointing away ("out") to pointing toward ("in") active site rotameric conformation. This study provides for the first time, to our knowledge, structural "snapshots" of hCA II intermediate states during the formation of the His64-mediated proton wire that is induced as CO2 is released. Comparison of the holo- and apo-hCA II structures shows that the solvent network rearrangements require the presence of the zinc ion. [ABSTRACT FROM AUTHOR]

It is widelyaccepted that an efficient oxygen supplyand removal of CO2 in small flying insects are sufficiently performed by diffusion with open spiracles. This paper shows that in the tethered flying blowfly, gas exchange occurs byautoventilation and unidirectional airflow. The air is inspired through the mesothoracic spiracles (Sp1) during the downstroke of the wings and is expired through the metathoracic spiracles (Sp2) during the upstroke. This directed airflow through the thoracic tracheal system was documented by pre-atrial pressure measurements at the Sp1 and Sp2, revealing a sub-atmospheric mean pressure at the Sp1 and an over-atmospheric mean pressure at the Sp2. In the mesothoracic air sacs, the mean pressure is subatmospheric, conditioned by the only slightly open spiracles. In a split flow-through chamber experiment, the CO2 released through the Sp2 confirmed this unidirectional respiratory gas flow, implicating an inner tracheal valve. In the thoracic tracheal system, the PO2 during flight exceeds the high resting PO2 by 1-2 kPa, reaching nearly atmospheric values. In the abdominal large air sacs, the PO2 drops during flight, probably due to the accumulation of CO2. Periodic heartbeat reversals continue during flight, with a higher period frequency than at rest, supporting the transport of CO2 via the haemolymph towards the metathoracic tracheae and abdominal air sacs. [ABSTRACT FROM AUTHOR]

• Mass and CO 2 efflux of the litter retained within a 40-m tall canopy were measured. • Mass of the retained litter was the greatest at a height of 0–2 m. • CO 2 efflux from the retained litter did not differ with height. • The retained litter sporadically contributed to carbon storage. • The retained litter contributed little to aboveground carbon release. Litter usually drops to the ground, but some is retained within the canopy. Mass and CO 2 efflux from retained litter may play a significant role in carbon cycling in tropical rainforests where emergent trees with complicated canopy structures are observed. This study aimed to show vertical variation in the mass and CO 2 efflux (R litter) of the retained litter and examined its contribution to carbon cycling in a Bornean tropical rainforest. The retained litter was collected from six 40 m tall columns with a radius of 1.6 m using an 85 m tall crane at six subplots. Dry mass and R litter were measured in the laboratory. The mass of the retained litter from the sampling points ranged from 0.35 g to 187.0 g, and R litter of the retained litter (42.4 ± 43.4 mg CO 2 kg−1 h −1) was significantly lower than that of the soil surface litter (85.9 ± 39.2 mg CO 2 kg−1 h −1) because of the lower water content in the retained litter. The mean mass of the retained litter measured from the ground to the canopy was 40.6 ± 22.2 g m −2. The greatest mass was observed at a height of 0–2 m. The ratio of the retained litter mass to the soil surface litter mass ranged from 1.0 to 11.5% with a mean of 5.2%, suggesting that litter retained within the canopy can contribute to carbon storage in this forest. On the other hand, R litter did not differ with height, and the ratio of R litter to aboveground autotrophic respiration was less than 1%. This study is the first to show that the litter retained within the canopy can sporadically be a moderate hot spot for C storage, but it is not a significant source of released CO 2. [ABSTRACT FROM AUTHOR]

• Oxygen isotopes in river water sulfate enable partitioning of sulfate source. • Isotope data demonstrates 56% of sulfate in the Mekong River is derived from pyrite. • Pyrite oxidation releases CO 2 through weathering of carbonates with sulfuric acid. • Carbon consumption from silicate weathering offset in large rivers. The weathering of carbonate rocks with sulfuric acid releases carbon dioxide (CO 2) to the atmosphere, offsetting the CO 2 drawdown from carbonic acid weathering of silicates thought to regulate global climate. Quantifying CO 2 release from sulfuric acid weathering requires the partitioning of riverine sulfate between its two main sources: sedimentary sulfate and sulfide. Although the sulfur (δ 34 S S O 4 ) and oxygen (δ 18 O S O 4 ) isotope ratios of sedimentary sulfates (gypsum and anhydrite) of different ages are well constrained, the δ 34 S of sulfide minerals is highly variable, restricting the utility of δ 34 S for partitioning sulfur sources. Here, we use oxygen isotope ratios in the river water (δ 18 O H 2 O) and sulfate molecules (δ 18 O S O 4 ) to partition the fraction of sulfate and associated uncertainty delivered by the oxidative weathering of pyrite (f pyr). The partitioning is illustrated using the Mekong River, one of the world's largest river basins, presenting new δ 18 O S O 4 , δ 18 O H 2 O and δ 34 S S O 4 data collected on 18 tributaries and 6 mainstem sites over two field seasons at peak flux. The geological, geomorphological and climatic diversity of the Mekong River basin make it an ideal field site to quantify the role of sulfuric acid weathering and its implications for the carbon cycle. There is a 12‰ range in both the difference between δ 18 O S O 4 and δ 18 O H 2 O (Δ 18 O S O 4 − H 2 O) and δ 34 S in the river waters of the basin. In the Mekong tributaries, sources of sulfate are highly variable with the fraction of sulfate derived from pyrite oxidation (f pyr) ranging from 0.19 to 0.84. In the mainstem, f pyr reflects the flux-weighted mean of these tributary inputs, with 56 ± 7 % (1 σ) of the sulfate delivered to the ocean at the Mekong mouth being derived from the oxidative weathering of pyrite. As a result, we estimate that ∼70% of CO 2 consumed through silicate weathering in the Mekong basin is offset by the release of CO 2 via the dissolution of carbonates by sulfuric acid. [ABSTRACT FROM AUTHOR]

• Real-time monitoring of CO 2 release. • Measurements of water column pH and pCO 2 via towed Video-CTD system. • Assessment of towed sensors capacity to detect potential CO 2 leakage in the water column. • Estimation of thresholds for the detection of anomalous pCO 2. Within the framework of the STEMM-CCS project, a controlled CO 2 release experiment was conducted under real-life conditions in the Goldeneye complex area, a depleted gas field located in the UK sector of the North Sea. Here, the viability of water column monitoring for the detection of the injected CO 2 is evaluated. Real-time pH and pCO 2 measurements were taken in the water column during the CO 2 release experiment. Monitoring was carried out throughout the full water column, from the near-seafloor to the sea surface, in order to assess the spatial extent of the CO 2 release. The dispersion of the CO 2 plume was strongly influenced by tidal circulation in the area. The strongest signals were detected within 8 m of the bubble stream during low tide. The lowest pH and highest pCO 2 values were 7.965 and 942.1 µatm, respectively, corresponding to variations of 16.4% [ H +] and 125.6% from baseline values. The pCO 2 baseline dynamics of Goldeneye area were assessed by the evaluation of the natural pCO 2 -O 2 covariance. The estimation of seasonal thresholds for anomalous pCO 2 (pCO 2 :O 2 ratio May = 1.63 ± 0.04) allowed us to assess with confidence the non-biological origin of the detected CO 2 during the release experiment. [ABSTRACT FROM AUTHOR]

• Weather, soil moisture, CO 2 concentration and fluxes were monitored for 965 days in South Korea. • Heterogeneities of soils have little effect on simulated CO 2 fluxes. • Increased soil moisture content results to high CO 2 concentration in soil profile. In Eumseong, Republic of Korea, a controlled CO 2 release site was designed by Korea CO 2 Storage Environmental Management (K-COSEM) Research Center to evaluate properly integrated CO 2 monitoring tools at the soil surface. CO 2 was released from the 55 m-length PVC-pipe buried at 2.5 m-depth, and then, CO 2 concentration and flux were monitored from August 1, 2015 to March 21, 2018 (965 days). Influencing environmental factors such as meteorological data, soil moisture and temperature at 5 different depths were monitored concurrently. The measured soil moisture content decreased rapidly when the soil temperature dropped below 0 °C. When CO 2 release began, both surface CO 2 flux and soil CO 2 concentration increased with a time lag. However, with occurrence of precipitation events, CO 2 flux decreased to almost 0 cm3 cm−2 day−1 but soil CO 2 concentration increased rapidly. The HYDRUS-SOILCO2 predicted soil moisture, temperature and natural background CO 2 flux compared to measured data (R2 = 0.74, 0.89, and 0.85). The 10 scenarios were constructed with different soil characteristic curves. Unlike soil moisture content, the simulated natural CO 2 flux did not depend heavily on soil characteristics. The mass of released CO 2 was estimated by the difference between the measured CO 2 flux data during the release test and natural CO 2 prediction model. At the 2nd CO 2 release test, there was 1.5 times difference between the actual released CO 2 mass and calculated CO 2 mass. [ABSTRACT FROM AUTHOR]

The frequent environment-unfriendly treatments of agro-industrial bio-wastes cause severe pollution through air pollution and through residual effluents and hazardous solid waste. These bio-wastes can contain phenolic compounds, forms of phenolic acids and flavonoids in plants. They are however the most abundant class of many phytochemicals and have been given great interest due to their health advantage and high economic value. An interesting upgrading of these bio-wastes may consist in obtaining a concentrated extract of phenolic compounds using no-toxic solvents, hence protecting the environment and human health. In this work, different alternatives of the extraction process were evaluated using an exergetic analysis. The energy and water consumptions, CO 2 emissions, exergetic yield, wasted and destroyed exergy were calculated. It was found that several alternatives for recycle streams were convenient (streams with higher chemical exergy were not discharged into the environment). The energy and water consumption for the best alternative (ethanol-water ratio 1/1 including recycle stream, named E-W 1/1 Rec) were 567 MJ/h and 105 kg/h, respectively and the CO 2 emission was 105 kg/h. The calculated exergy destruction indicated that the evaporation and distillation stages may be optimized towards a more sustainable operation. It is not advisable to dry the bio-waste if it will be immediately processed once generated. Image 1 • Eco-friendly alternative for obtaining polyphenols from bio-waste. • Energy and water consumptions are evaluated. • Alternatives including recycle streams, drying stages and different ethanol-water ratios are considered. • CO 2 emission, environmental indicators and exergy efficiency are calculated. [ABSTRACT FROM AUTHOR]

Background: Milk fermentation takes place in the presence of various micro-organisms, producing a variety of dairy products. The oldest of them is kefir, which is usually produced by the fermentation of milk with kefir grains. Carbon dioxide (CO 2 ), as one of the process products, also contributes to the characteristic flavor of kefir. The amount of CO 2 generated during fermentation depends on bioprocessing conditions and may change, which is not desirable at the industrial level., Results: In this study we developed a simplified mathematical model of CO 2 release in the milk-fermentation process. An intuitive approach based on superposition and experimental analysis was used for the modeling. The chemical system studied was considered as a two-input (temperature, rotational frequency of the stirrer) one-output (CO 2 concentration) dynamic system., Conclusion: Based on an analysis of CO 2 release transients in the case of non-simultaneous stepwise changed input quantities, two differential equations were defined that describe the influence of the two input quantities on the output quantity. The simulation results were verified by experiments. The proposed model can be used for a comprehensive analysis of the process that is being studied and for the design and synthesis of advanced control systems, which will ensure a controlled CO 2 release at the industrial level. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

Carbonic anhydrases are mostly zinc metalloenzymes that catalyze the reversible hydration/dehydration of CO2/HCO3 (-) Previously, the X-ray crystal structures of CO2-bound holo (zinc-bound) and apo (zinc-free) human carbonic anhydrase IIs (hCA IIs) were captured at high resolution. Here, we present sequential timeframe structures of holo- [T = 0 s (CO2-bound), 50 s, 3 min, 10 min, 25 min, and 1 h] and apo-hCA IIs [T = 0 s, 50 s, 3 min, and 10 min] during the "slow" release of CO2 Two active site waters, WDW (deep water) and WDW' (this study), replace the vacated space created on CO2 release, and another water, WI (intermediate water), is seen to translocate to the proton wire position W1. In addition, on the rim of the active site pocket, a water W2' (this study), in close proximity to residue His64 and W2, gradually exits the active site, whereas His64 concurrently rotates from pointing away ("out") to pointing toward ("in") active site rotameric conformation. This study provides for the first time, to our knowledge, structural "snapshots" of hCA II intermediate states during the formation of the His64-mediated proton wire that is induced as CO2 is released. Comparison of the holo- and apo-hCA II structures shows that the solvent network rearrangements require the presence of the zinc ion.