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[Display omitted] • The deviation of N 2 O emission factor (EF) from short-term monitoring can reach 20%. • The N 2 O EF for sludge incineration in China may be smaller than the default value. • The N 2 O EF decreases as the temperature in the furnace increases. • The N 2 O EF of the sludge incinerators with smaller heat loads fluctuates more. • The fluctuation range of the N 2 O EF narrows with the increase of temperature. The N 2 O emissions resulting from sludge incineration are estimated using the default values published by the Intergovernmental Panel on Climate Change (IPCC), which may differ significantly from the actual emissions. In this investigation, N 2 O emissions from four sludge incineration lines in two plants were monitored for varying durations. The variation in N 2 O emission factors (EFs) between incineration lines of the same plant was much smaller than the difference between different plants. Data on N 2 O EFs obtained from brief monitoring may contain variabilities of up to 30%. N 2 O EFs were more sensitive to temperature changes at low temperatures, necessitating extended monitoring periods to improve the reliability of N 2 O monitoring outcomes in cases of low furnace temperatures. Excessive use of the SNCR system to reduce NOx emissions resulted in concentrations of N 2 O and NH 3 in the exhaust gases exceeding NOx levels. In the case of furnace temperature control and advanced reburning technology, it is advisable to utilize actual monitoring data or the smaller default values provided by the IPCC in China. Otherwise, the estimated N 2 O emissions may exceed the actual emissions. [ABSTRACT FROM AUTHOR]

• Understanding the dynamics of N 2 O and CH 4 fluxes avoids emissions during storage. • Manure discharge release significant N 2 O and CH 4 emissions due to feed inefficiency. • Shortening manure storage is the most viable management at smallholder dairy farms. • Trade-offs between reducing CH 4 or N 2 O fluxes often appears in manure management. Storing manure emits greenhouse gas (GHG) emissions, including nitrous oxide (N 2 O) and methane (CH 4). However, the emissions from types of manure stored at smallholder dairy farms remains unknown. Hence, the study aims to analyse the dynamics of N 2 O and CH 4 from different types of dairy manure as affected by storage periods. We collected samples from fresh manure (FM-DF1), manure from communal ponds in an urban dairy farm (IP-DF1, FP-DF1, MS-DF1), fresh manure from an urban dairy farm (FM-DF2), and fresh (FM-DF3), separated (FS-DF3), and fermented manure (FR-DF3) from a peri -urban dairy farm, and stored them for eight weeks and analyse them using the closed chamber method. The changes of manure composition including total solids (TS), nitrogen (N), ammonia–nitrogen (N-NH 3), and carbon (C) were analysed. Results indicated an increase TS in all treatments except for MS-DF1, while N, N-NH 3 , and C content decreased in all treatments. The N 2 O emissions formed at the start, peaked in the middle, and declined towards the end storage period. The CH 4 emissions peaked at the start and decreased until the end storage period. Treatment FM-DF2 yield highest cumulative of N 2 O (0.82 g/m2) and CH 4 (41.63 g/m2) compared to other fresh manure treatment. A mixed model analysis detected a significant interaction (p < 0.05) between manure types and storage periods. In conclusion, manure types and storage periods affect the emissions. Changes in manure concentration during storage and animal diets are two important factors influencing emissions. Strategies to reduce emissions include reducing moisture content in manure, shortening storage periods, and improving feed quality. [ABSTRACT FROM AUTHOR]

Background: Over the last decade, there has been an emerging trend of recreational misuse of several drugs and inhaled solvent including ethyl chloride. This case report follows CARE guidelines and highlights, with supporting video, the neurological features of ethyl chloride intoxication. Case presentation: A 48-year-old man was seen for the sudden occurrence of an unsteady gait with dizziness. His only medical history was a chronic and treated HIV infection without any complications. Clinical examination revealed a cerebellar syndrome associated with impairment of short-term memory. Biological and radiological workups were normal. After several days, the patient recalled ethyl chloride inhalation. He fully recovered after being discharged from hospital. Conclusion: Clinicians should recognise the clinical features and neurological manifestations of ethyl chloride intoxication due to the potential fatal cardiovascular complications of this intoxication. [ABSTRACT FROM AUTHOR]

Denitrification and anaerobic ammonium oxidation (anammox) are key processes for nitrogen removal in aquaculture, reducing the accumulated nitrogen nutrients to nitrogen gas or nitrous oxide gas. Complete removal of nitrogen from aquaculture systems is an important measure to solve environmental pollution. In order to evaluate the nitrogen removal potential of marine aquaculture ponds, this study investigated the denitrification and anammox rates, the flux of nitrous oxide (N2O) at the water–air interface, the sediment microbial community structure, and the gene expression associated with the nitrogen removal process in integrated multi-trophic aquaculture (IMTA) ponds (Apostistius japonicus-Penaeus japonicus-Ulva) with different culture periods. The results showed that the denitrification and anammox rates in sediments increased with the increase of cultivation periods and depth, and there was no significant difference in nitrous oxide gas flux at the water–air interface between different cultivation periods (p > 0.05). At the genus and phylum levels, the abundance of microorganisms related to nitrogen removal reactions in sediments changed significantly with the increase of cultivation period and depth, and was most significantly affected by the concentration of particulate organic nitrogen (PON) in sediments. The expression of denitrification gene (narG, nirS, nosZ) in surface sediments was significantly higher than that in deep sediments (p < 0.05), and was negatively correlated with denitrification rate. All samples had a certain anammox capacity, but no known anammox bacteria were found in the microbial diversity detection, and the expression of gene (hzsB) related to the anammox process was extremely low, which may indicate the existence of an unknown anammox bacterium. The data of this study showed that the IMTA culture pond had a certain potential for nitrogen removal, and whether it could make a contribution to reducing the pollution of culture wastewater still needed additional practice and evaluation, and also provided a theoretical basis for the nitrogen removal research of coastal mariculture ponds. [ABSTRACT FROM AUTHOR]

Key long-lived greenhouse gases (CO2, CH4, and N2O) are perhaps among the best-studied components of the Earth's atmosphere today; however, attempts to predict or explain trends or even shorter-term variations of these trace gases are not always successful. Infrared spectroscopy is a recognized technique for the ground-based long-term monitoring of the gaseous composition of the atmosphere. The current paper is focused on the analysis of new data on CO2, CH4, and N2O total columns (TCs) retrieved from high resolution IR solar spectra acquired during 2009–2022 at the NDACC atmospheric monitoring station of St. Petersburg State University (STP station, 59.88°N, 29.83°E, 20 m asl.). The paper provides information on the FTIR system (Fourier-transform infrared) installed at the STP station, and an overview of techniques used for the CO2, CH4, and N2O retrievals. Trends of key greenhouse gases and their confidence levels were evaluated using an original approach which combines the Lomb–Scargle method with the cross-validation and bootstrapping techniques. As a result, the following fourteen-year (2009–2022) trends of TCs have been revealed: (0.56 ± 0.01) % yr−1 for CO2; (0.46 ± 0.02) % yr−1 for CH4; (0.28 ± 0.01) % yr−1 for N2O. A comparison with trends based on the EMAC numerical modeling data was carried out. The trends of greenhouse gases observed at the STP site are consistent with the results of the in situ monitoring performed at the same geographical location, and with the independent estimates of the global volume mixing ratio growth rates obtained by the GAW network and the NOAA Global Monitoring Laboratory. There is reasonable agreement between the CH4 and N2O TC trends for 2009–2019, which have been derived from FTIR measurements at three locations: the STP site, Izaña Observatory and the University of Toronto Atmospheric Observatory. [ABSTRACT FROM AUTHOR]

Rural drainage ditches serve as important sinks for heavy metals and antibiotics. However, the combined effects of heavy metals and antibiotics on ecological processes and functions in ditches remain unclear. We studied the combined effects of cadmium and doxycycline on nitrification, denitrification, anaerobic ammonia oxidation, and nitrous oxide emission rates in constructed ditch wetlands during 84 days. Results show that combined pollution decreased denitrification and anaerobic ammonia oxidation rates, but increased nitrous oxide production rates. The addition of either cadmium or doxycycline decreased the glucokinase and glyceraldehyde-3-phosphate dehydrogenase activities, and their combined pollution had a higher impact on adenosine triphosphate than on nicotinamide adenine dinucleotide. Moreover, the activities of the electron transport system, nitrate reductase, and nitrite reductase were enhanced by short-term pollutant exposure, but inhibited by long-term pollutant exposure. Structural equation modelling further revealed that electron production and transport impacted the rates of denitrification, anaerobic ammonia oxidation, and nitrous oxide production directly and indirectly by changing the activities of nitrate and nitrite reductases. [ABSTRACT FROM AUTHOR]

Background and Aims: The agriculture sector is a major producer of greenhouse gases. To successfully transition to a green economy, we should further optimise agriculture practices so that we offset emissions while preserving crop productivity. We questioned here how two common organic management practices, reducing irrigation and conservation tillage as well as their interaction modify N2O emissions. Methods: We synthesized across 265 studies and combined a series of linear models and a meta-analytical method of moments to analyze our data. Results: We observed that reducing irrigation induced increases of about 66.1% in N2O emissions in rice but declines of over 17% for other crops, subject to mean annual temperature conditions. No tillage lowered N2O emissions, which was not the case for the reduced tillage practice. This resulted into the overall effect of conservation tillage practices on N2O emissions being non-significant. Conclusion: We present evidence that managing N2O emissions from agroecosystems depends strongly on climatic conditions and crop type used. Mapping those dependencies facilitates budgeting greenhouse gas emissions from agroecosystems and smooths the path towards meeting sustainability targets in agriculture and horticulture. [ABSTRACT FROM AUTHOR]

Headwater streams play a large role in aquatic greenhouse gas emissions. Carbon dioxide (CO2) and dissolved oxygen in streams often undergo changes through diel cycles. However, methane (CH4) and nitrous oxide (N2O) have unknown diel dynamics. Here, we reveal consistent patterns in CO2, CH4, and N2O over diel cycles and during flood events using high‐frequency continuous observations in a subtropical headwater stream. Diel cycles were most pronounced during baseflow. Increased nighttime discharge due to higher groundwater inputs enhanced gas transfer velocities and concentrations. Overall nocturnal emissions were 31%, 68%, and 32% greater than daytime for CO2, CH4, and N2O, respectively. Floods dampened diel signals. If both flood events and diel patterns are neglected, estimates of greenhouse gas emissions from headwaters may be greatly underestimated. Overall, CH4 and N2O emissions from headwater streams may be underestimated by ~ 20–40% due to a lack of observations during nighttime, floods, and in warmer climates. [ABSTRACT FROM AUTHOR]

Background: Recreational nitrous oxide (N2O) use has become more widespread worldwide, leading to an increase in myelopathies and peripheral neuropathies. The aim of this study was to describe clinical and socioeconomical characteristics of severe N2O-induced (NI) neurological disorders (NI-NDs), to determine its incidence in the Greater Paris area and to compare it with that of similar inflammatory neurological disorders. Methods: We performed a retrospective multicentric cohort study of all adult patients with severe NI-NDs in the neurology and general internal medicine departments of the Greater Paris area from 2018 to 2021. The incidence was compared with that of non-NI-myelitis and Guillain–Barré syndrome (GBS) using a sample of 91,000 hospitalized patients sourced from health insurance data. Results: Among 181 patients, 25% had myelopathy, 37% had peripheral neuropathy and 38% had mixed disease. Most were aged between 20 and 25 years, lived in socially disadvantaged urban areas, and exhibited high rates of unemployment (37%). The incidence of NI-NDs increased during 2020 and reached a peak mid-2021. The 2021 incidence in 20–25-year-olds was 6.15 [4.72; 8.24] per 100,000 persons for NI-myelopathy and 7.48 [5.59; 9.37] for NI-peripheral neuropathy. This was significantly higher than for non-NI-myelitis (0.35 [0.02; 2.00]) and GBS (2.47 [0.64; 4.30]). The incidence of NI-NDs was two to three times higher in the most socially disadvantaged areas. Conclusion: The recent increase in recreational N2O use has led to a rise in the incidence of severe NI-NDs, particularly in young adults with low socioeconomic status for whom NI-NDs strongly outweigh similar neurological disorders. [ABSTRACT FROM AUTHOR]

CO2 reduction is appealing for the long‐term production of high‐value fuels and chemicals. Herein, using density functional theory (DFT) based calculations, we study the CO2 reduction pathway to formic acid using aluminum hydride and phosphine derivatives. Our primary focus is on aluminum hydride derivatives, aimed at improving the efficiency of the CO2 reduction process. Substituents with σ‐donating properties at the aluminum center are discovered to lower the activation barriers. We demonstrate how di‐tert‐butylphosphine oxide (LB‐O)/di‐tert‐butylphosphine sulfide (LB‐S)/di‐tert‐butylphosphanimine (LB‐N) work together with aluminum hydride to facilitate CO2 reduction process and generate in‐situ frustrated Lewis pairs (FLPs), such as FLP‐O, FLP‐S, and FLP‐N. The activation strain model (ASM) analysis reveals the significance of strain energy in determining activation barriers. EDA‐NOCV and PIO analyses elucidate the orbital interactions at the corresponding transition states. Furthermore, the study delves into the activation of various small molecules, such as dihydrogen, acetylene, ethylene, carbon dioxide, nitrous oxide, and acetonitrile, using those in‐situ generated FLPs. The study highlights the low activation barriers and emphasizes the potential for small molecule activation in this context. [ABSTRACT FROM AUTHOR]

In this work, we investigated the influence of ammonia addition in the immersion process of active species on the dispersion and activity of copper-supported porous hollow silica–alumina sphere catalysts for decomposition of nitrous oxide. The porous hollow sphere support was prepared using surfactant micelles and oil droplets in an aqueous solution as dual templates, and active copper species were supported on the resulting hollow spheres via the immersion process. The amount of supported copper species on the hollow sphere support tended to increase with increasing amount of aqueous ammonia solution used in the immersion process, suggesting that the formation of copper ammine complexes induced strong interactions between the complexes and silica surface from the results of EDS and XPS analyses. Specific surface areas and pore volumes of the copper-supported hollow spheres tended to increase with increasing the amount of aqueous ammonia solution identified from the results of nitrogen sorption measurements, indicating that the confined active copper species in the nanospaces in the hollow spheres' shells increased with increasing the amount of aqueous ammonia solution. A significantly high amount of pores with a diameter of around 3 nm were observed in the copper-supported hollow spheres prepared with the amount of aqueous ammonia solution of 2.64 mL from the estimation of their pore size distributions, indicating that the confined active copper species in the nanospaces in the shells did not completely plug the pores. The catalytic activity of the copper-supported hollow sphere catalyst for the decomposition of nitrous oxide depended on the dispersion of the active species, and the catalyst prepared with the amount of aqueous ammonia solution = 2.64 mL exhibited the highest activity and included highly dispersed active copper species even after the catalytic reaction from the result of the XRD profiles. [ABSTRACT FROM AUTHOR]

Background and Aim Methods Results Interpretation Recreational use of nitrous oxide (N2O) has been associated with the development of severe nitrous oxide‐induced neuropathy (N2On). Follow‐up of these patients poses challenges, and their clinical progression remains largely unknown. The identification of prognostic factors is made difficult by the lack of standardized longitudinal assessments in most studies. The objective was to document the course of neuropathy through systematic follow‐up assessments in N2On patients to identify prognostic factors for persistent disability after 6 months.We gathered demographic, clinical, biological, and electrophysiological data from N2On patients hospitalized in the Referral center in Marseille, both at baseline and during a standardized follow‐up assessment at 6 months.We retrospectively included 26 N2On patients (mean age 22.6 ± 4.4). Significant improvements were observed in all main clinical scores including Rankin, ONLS, and MRC testing (p < .01). Electrophysiological studies (EDX) revealed a predominantly motor neuropathy with marked reduction in CMAP in the lower limbs at baseline, and no significant improvement in motor parameters (p = .543). Rankin score at 6 months correlated with the initial weekly N2O consumption (r = .43, p = .03) and the CMAP sum score in the lower limbs at the first EDX (r = −.47, p = .02). Patients with and without myelitis showed similar Rankin and ONLS score after 6 months.The clinical course generally improved favorably at 6 months with notable amelioration in the primary disability scores, sensory deficits, and ataxia. However, distal motor impairment associated with peripheral neuropathy persisted, with distal axonal loss emerging as the main prognostic factor for long‐term disability in these young patients. [ABSTRACT FROM AUTHOR]

Background: Nitrous oxide (N2O) has been in industrial and recreational use since the 18th century and is commonly perceived as a safe substance. Despite its increasing uptake, there is a lack of data on N2O-related harm. This article explores the misuse of N2O associated with various complications, with a focus on frostbite as a novel phenomenon. We aimed to review the existing body of literature and describe the epidemiology, presentation, pathophysiology, and management of patients with N2O-related frostbite injuries in the upper aerodigestive tract. Methods: A literature search was conducted across PubMed, MEDLINE and Embase databases, focusing on English language articles related to N2O use patterns, associated injuries, pathophysiology, investigations, and management. Results: The search yielded 122 results, of which fifteen case reports and case series were included in the study. There are 54 total cases included in the analysis. There is an equal distribution of males and females among a young population with a median age of 27.5 years. Presentations of skin and mucosal injuries across different anatomical sites as well as their management approaches are described. Conclusions: The pathophysiology of frostbite involves both direct and indirect effects, leading to tissue ischaemia, inflammation, and immune responses. Complications, including airway obstruction, underscore the severity of N2O-related injuries. Management strategies include securing the airway, surgical debridement, and pharmacological interventions such as prophylactic corticosteroids and antibiotics. N2O is a documented causative agent of frostbite injuries. Awareness of its rising prevalence and potential complications is key in the treatment of patients with complications sustained from the use of N2O. Level of evidence: Not ratable [ABSTRACT FROM AUTHOR]

α-CD:N2O "host-guest" type complexes were formed by a simple solid–gas reaction (N2O sorption into α-CD) under different gas pressures and temperatures. The new N2O inclusion method applied in the present study was compared with the already known technique based on the crystallization of clathrates from a water solution of α-CD saturated with N2O. A maximum storage capacity of 4.5 wt.% N2O was achieved when charging the cyclodextrin from a gas phase. The amount of included gas decreases to 1.3 wt.% when the complex is stored in air at 1 atm and room temperature, analogous to that achieved by the crystallization of α-CD:N2O. Furthermore, it was shown that the external coordination of N2O to either the upper or lower rim of α-CD without hydration water displacement is the preferred mode of binding, due to hydrogen bonds with neighboring -OH groups from the host macrocycle and three of the hydration water molecules nearby. The capacity of α-CD to store N2O and the thermal stability of the α-CD:N2O complex demonstrated promising applications of these types of complexes in food and beverages. [ABSTRACT FROM AUTHOR]

• Vertical column density and column averaged dry air concentrations of GHGs were retrieved from FTIR using GFIT model. • Seasonal and interannual variations of GHGs were studied. • FTIR retrieved X CO 2 and X CO data were compared with satellite data. Solar absorption spectra collected using a ground-based Fourier Transform Infrared (FTIR) Spectrometer were used to retrieve the column-averaged concentrations (X) of CO 2 , CH 4 , CO, and N 2 O during the years 2016–2019 in the Suburban region of Shadnagar, Telangana, India. For the research period, the diurnal mean amplitudes of X CO 2 , X CH 4 , X CO, and X N 2 O are ∼ 13 ppmv, ∼50 ppbv, ∼13 ppbv, and ∼ 19 ppbv respectively. Strong seasonality at the study site is indicated by the seasonal variations of X CO 2 and X CO of 18.3 ppmv and 39.2 ppbv, respectively. Additionally, we compared FTIR data to X CO 2 detected by Orbiting Carbon Observatory-2 (OCO-2) and CO columns from Measurements of Pollution in the Troposphere (MOPITT). For the X CO 2 and CO columns, the comparison research shows a mean relative bias between FTIR data and satellite data of 0.92 % and 0.71 %, respectively. The FTIR and satellite data show a Pearson correlation coefficient (r) of 0.71 (X CO 2 , N = 26 co-located) and 0.60 (CO columns, N = 44), respectively. The findings demonstrate a good agreement between our data and satellite data. [ABSTRACT FROM AUTHOR]

Background Case Presentation Discussion and Conclusions Chronic nitrous oxide (N2O) use causes inactivation of vitamin B12, resulting in neurological and psychiatric symptoms. This case series presents all N2O‐related presentations to the emergency department at Royal Perth Hospital between June 2019 and June 2021, alongside the costs of these admissions.Twenty‐two patients were identified; 68% (n = 15) were male. The median age was 22.4 years (interquartile range [IQR], 20–30). Median daily number of N2O bulbs inhaled was 150 (IQR, 64–300) with a median duration of use of 9 months (IQR, 3–12). Presentations included ataxia, paraesthesia and falls (n = 18), urinary retention (n = 3) and psychotic symptoms (n = 2). Fourteen patients had severe symptoms prompting a magnetic resonance imaging of brain and spine, confirming 12 cases of subacute combined degeneration of the spinal cord. All patients had IMI vitamin B12 therapy, while 14 had oral methionine therapy. The median length of admission was 4 days (IQR 1–23 days). The median cost of admission per day for patients where costs were accessible (n = 7) was $2061 (IQR, $1903‐$2860).A case series of symptomatic chronic N2O use with severe neurological sequelae and significant costs associated per admission. Triangulation of emergency department and Ecstasy and Related Drugs Reporting System data helped prompt a swift public health response, including mandatory warning labels, limits to transaction amounts and legislative changes to the Medicines and Poisons Act to make it illegal for sale if there is a suspicion that it will be abused. [ABSTRACT FROM AUTHOR]

Nitrous oxide (N2O) is a greenhouse gas produced in the manufacture of 6,6‐nylon and nitric acid. While an attractive oxidant that releases only N2 as a by‐product, the kinetic stability of N2O typically requires high temperatures and pressures for activation. This work describes initial kinetics of oxygen transfer in the epoxidation of cholesteryl acetate with N2O catalysed by D4‐Ru(VI)(por)(O)2 complexes in efforts to provide a better mechanistic understanding of this chemistry. Insights include a need for low concentrations of the alkene to avoid competitive binding to the metal, possible saturation behavior at high N2O pressures, transfer of only one oxygen of RuVI(O)2 to substrate and a possible catalyst turnover involving disproportionation of RuIV(O) and RuIV(O)(N2O) to active RuVI(O)2, RuIV(O) and N2. These insights will be used in future designs of improved catalysts and reaction protocols that may operate efficiently at low pressures of N2O and ambident temperature. [ABSTRACT FROM AUTHOR]

Due largely to the high stability and the potential ozone‐depleting, the transformation of greenhouse gas nitrous oxide has gained much attentions. In present paper, a new insight into the deoxygenation of nitrous oxide with silane was reported by using oriented external electric field (OEEF) as a catalytic strategy. When the OEEF was employed, the reaction barrier of deoxygenation was marvelously decreased as it was oriented along the positive NO/OSi bond‐axis. Especially the field strength is 300 × 10−4 a.u., the differences are up to 22.4/18.3 kcal mol−1 as compared with that of nonfield. In addition, once the H atom in SiH4 was replaced by methyl, two reaction modes were obtained, in which the deoxygenation process was easier when the N2O captured the H atom attached to the Si atom, not attached to the C atom. Further, the solvent effects of deoxygenation reaction were also considered, but with a weak influence were obtained. [ABSTRACT FROM AUTHOR]

Aim: Incorporating non-bloat legumes into grass pastures can reduce enteric methane and alter cattle urinary urea N output by increasing protein intake. Deposition of high urea N urine influences soil N-cycling microbes and potentially N2O production. We studied how urine urea N concentration affects soil nitrifier and denitrifier abundances, activities, and N2O production. Methods: 15N13C-labelled urea dissolved in cattle urine was added at 3.5 and 7.0 g L−1 to soils from a grazed, non-bloat legume pasture and incubated under controlled conditions. CO2, N2O, 13C-CO2, and 15N-N2O production were quantified over 240 h, along with nitrifier and denitrifier N-cycling genes and mRNA transcripts. Results: High urea urine increased total N2O relative to the control; low urea was not significantly different from the control or the high urea treatment. As a result, N2O-N emission factors were not significantly different between the low urea treatment (1.17%) and high urea treatment (0.94%). Doubling urea concentration doubled CO2-Curea and N2O-Nurea but not total N2O-N. Urine addition initially inhibited then increased AOB transcripts and gene abundances. nirK and nirS transcript abundances indicated that denitrification by ammonia oxidizers and/or heterotrophic denitrifiers dominated N2O production. Urine addition increased nosZ-II vs. nosZ-I transcripts, improving soil N2O reduction potential. Conclusion: Characterizing this interplay between nitrifiers and denitrifiers improves the understanding of urine patch N2O sinks and source dynamics. This mechanistic information helps to explain the constrained short-term N2O emissions observed in response to excess urine N excretion from cattle consuming high protein diets, e.g. non-bloat legumes. [ABSTRACT FROM AUTHOR]

Climate change-related warming and increased precipitation may alter winter snow cover and thawing events, and therefore, may carry significant consequences for nitrous oxide (N2O) production pathways such as denitrification, and the abundance and expression of denitrifying microorganisms. We used a soil microcosm study to investigate the combined effect of soil thaw temperature, initial water filled pore space (WFPS) prior to soil freezing, and snowmelt infiltration simulated by the addition of water on N2O emission and denitrification rates, soil respiration rate, and the abundance and transcription of denitrifying (nirK, nirS, and nosZ) bacteria during a single freeze-thaw event. Soil respiration rate was primarily controlled by an increase in soil thaw temperature, whereas soil N2O emission and denitrification rates were generally greater in soils with a higher initial WFPS and soil thaw temperature. In contrast, snowmelt infiltration generally had a negligible effect on these rates, which may be related to pre-existing soil conditions that were already conducive to denitrification. Unexpectedly, the nosZ transcript/nosZ gene abundance ratio was lower in soils thawed at 8.0 °C compared to 1.5 °C; however, this may have resulted in a lower N2O reduction, thus explaining the greater levels of N2O emitted from soils thawed at 8.0 °C. Overall, this study demonstrated that increased N2O production during a single freeze-thaw event was primarily linked to antecedent conditions of high initial WFPS, soil thaw temperature, and a synergistic interplay between these two environmental parameters, and provides evidence that an increase in annual temperature and precipitation, along with the timing of precipitation, may further stimulate N2O production pathways. [ABSTRACT FROM AUTHOR]

A stable dialkylgermanone was generated by mixing a solid of the corresponding dialkylgermylene and gaseous N2O. While the dialkylgermanone is marginally persistent in solution and gradually converts to its head‐to‐tail dimer at room temperature, the addition of THF to the dialkylgermanone provided an isolable THF‐coordinated dialkylgermanone. The THF‐coordinated dialkylgermanone reacts with H2O, THF, and B(C6F5)3 similar to the corresponding base‐free two‐coordinate dialkylsilanone. The dialkylgermanone undergoes deoxygenation in the presence of triphenylphosphine to provide the corresponding germylene and olefination upon treatment with phosphaylide Ph3PCHPh to afford the corresponding Ge=C bond compound (germa‐Wittig reaction). [ABSTRACT FROM AUTHOR]

Nitrogen losses of nitrous oxide (N2O) in grazed grassland are strongly driven by urine deposition by grazing ruminants. There is robust concern about applying nitrification inhibitor to mitigate nitrogen losses in global grasslands. However, the effect of dicyandiamide (DCD) on N2O emission rates and its driven factors remain unclear due to spatial heterogeneity. In the present study, we synthesized 133 group data from 69 published articles. It was indicated that effect size was -0.784±0.048 (P<0.0001) indicating a reduction of 54.34% in N2O emission rates. There was significant difference on effect size between different dose of nitrogen fertilization. Moderate dosage of DCD application was the best mitigation effect of 56.09%, which was significantly higher than light dosage of DCD application. Mixed effect model results revealed that precipitation, bulk density and air temperature could explain 16.93%, 12.31% and 3.02% variations in effect size. In addition, DCD application was an effective strategy to mitigate N2O emission rates in global grazed grasslands. [ABSTRACT FROM AUTHOR]

Sandy loamy soils are widely distributed in fluvial floodplains and experience flooding events frequently, resulting in a large amount of nitrous oxide (N2O) emissions. This case is more serious when the soil use is changed to paddies. It is of great significance to figure out the N2O consumption and its influencing factors in sandy loamy paddy soils to mitigate N2O emissions. In this study, three sandy loamy paddy soils (0–5 cm) originated from lake deposits were selected (S1, S2, and S3) as objectives. A certain concentration of exogenous N2O was added at the bottom of the flooded soil column to monitor the dynamics of N2O and nitrogen (N2) on the soil surface. Total N2O consumption, N2O uptake, and N2 production were quantified, and the abundance of nitrous oxide reductase genes (nosZI, and nosZII) and other soil properties (ammonium‐nitrogen, nitrate‐nitrogen, and dissolved organic carbon [DOC] content) were analyzed. The results showed that the sandy loamy paddy soil column with a depth of 0–5 cm could intercept more than 95% of the exogenous N2O under the flooded anaerobic condition, indicating that the three sandy loamy paddy soils all had extremely strong N2O consumption capacities. And the increment of N2 accounted for 68.73%–76.09% of the total N2O consumption, which had a stronger relationship with the increase of nosZI gene abundance than nosZII gene. In addition, the total N2O consumption and N2 increment of S1 and S3 soils were significantly higher than those of S2 soil. This difference was mainly related to soil organic matter content, total nitrogen content, DOC consumption, and the increase of nosZI gene abundance (p < 0.05). The strong N2O consumption potential of sandy loamy soils can provide feasible solutions for regulating N2O emissions in a wide range of similar environments in fluvial floodplains. Core Ideas: Over 95% of N2O in 5‐cm‐soil depth was consumed by flooded sandy loamy paddy soils.The microbial reduction of N2O to N2 is the main pathway of N2O consumption.N2O consumption and N2 increment dominated by nosZI‐containing microorganisms. [ABSTRACT FROM AUTHOR]

Incorporating large amounts of woody biomass into soil, such as in whole orchard recycling (WOR), can promote carbon sequestration, nutrient recycling, and ecosystem health in agricultural fields. Yet uncertainty regarding the effects of WOR on soil carbon (C) and nitrogen (N) dynamics influences management decisions. The objective of this research was to evaluate the effects of woodchip (WC) size and interaction with N fertilization on carbon dioxide (CO2) and nitrous oxide (N2O) emissions. An 8‐month incubation experiment incorporating WC (4% w/w, equivalent to ∼40 tons per acre) in four sieved sizes (0.2–1.6, 1.6–3.2, 3.2–6.4, and 6.4–12.7 mm) with and without N applications was conducted. All treatments with WC showed that CO2 emission peaked within the first week, then decreased drastically afterward. The CO2 peak delayed as the peak value decreased (WC size increased). The finest WC (<1.6 mm) yielded the lowest total CO2 emissions and resulted in the greatest increase in soil C at the end of incubation. Nitrogen application reduced total CO2 emissions by 1% in the smallest WC size and by 8%–9% for those larger than 1.6 mm. The N2O emissions spiked following each fertilizer application with lowest total emissions from the smallest WC size, suggesting substantial N immobilization. The results imply that larger WC sizes can delay C mineralization and reduce initial N immobilization risks, but the smallest WC size may have stabilized and increased soil organic carbon. This research increased our understanding on WC mineralization that can be used in WOR management. Core Ideas: There is a significant interaction between woodchip size and N application on both CO2 and N2O emissions.Smallest woodchip size gave highest initial CO2 emissions, but lowest total loss while increasing soil organic carbon.N application with woodchips resulted in significantly lower CO2 emissions.Woodchip size showed different impact on peak N2O emissions with time but no impact on total loss and soil N.Larger woodchip sizes showed delay in C mineralization, minimizing the initial N immobilization risk. [ABSTRACT FROM AUTHOR]

Plant metabolites significantly affect soil nitrogen (N) cycling, but their influence on nitrous oxide (N2O) emissions has not been quantitatively analyzed on a global scale. We conduct a comprehensive meta‐analysis of 173 observations from 42 articles to evaluate global patterns of and principal factors controlling N2O emissions in the presence of root exudates and extracts. Overall, plant metabolites promoted soil N2O emissions by about 10%. However, the effects of plant metabolites on N2O emissions from soils varied with experimental conditions and properties of both metabolites and soils. Primary metabolites, such as sugars, amino acids, and organic acids, strongly stimulated soil N2O emissions, by an average of 79%, while secondary metabolites, such as phenolics, terpenoids, and flavonoids, often characterized as both biological nitrification inhibitors (BNIs) and biological denitrification inhibitors (BDIs), reduced soil N2O emissions by an average of 41%. The emission mitigation effects of BNIs/BDIs were closely associated with soil texture and pH, increasing with increasing soil clay content and soil pH on acidic and neutral soils, and with decreasing soil pH on alkaline soils. We furthermore present soil incubation experiments that show that three secondary metabolite types act as BNIs to reduce N2O emissions by 32%–45%, while three primary metabolite classes possess a stimulatory effect of 56%–63%, confirming the results of the meta‐analysis. Our results highlight the potential role and application range of specific secondary metabolites in biomitigation of global N2O emissions and provide new biological parameters for N2O emission models that should help improve the accuracy of model predictions. [ABSTRACT FROM AUTHOR]

Nitrous oxide (N2O) emissions from livestock manure contribute significantly to the growth of atmospheric N2O, a powerful greenhouse gas and dominant ozone‐depleting substance. Here, we estimate global N2O emissions from livestock manure during 1890–2020 using the tier 2 approach of the 2019 Refinement to the 2006 IPCC Guidelines. Global N2O emissions from livestock manure increased by ~350% from 451 [368–556] Gg N year−1 in 1890 to 2042 [1677–2514] Gg N year−1 in 2020. These emissions contributed ~30% to the global anthropogenic N2O emissions in the decade 2010–2019. Cattle contributed the most (60%) to the increase, followed by poultry (19%), pigs (15%), and sheep and goats (6%). Regionally, South Asia, Africa, and Latin America dominated the growth in global emissions since the 1990s. Nationally, the largest emissions were found in India (329 Gg N year−1), followed by China (267 Gg N year−1), the United States (163 Gg N year−1), Brazil (129 Gg N year−1) and Pakistan (102 Gg N year−1) in the 2010s. We found a substantial impact of livestock productivity, specifically animal body weight and milk yield, on the emission trends. Furthermore, a large spread existed among different methodologies in estimates of global N2O emission from livestock manure, with our results 20%–25% lower than those based on the 2006 IPCC Guidelines. This study highlights the need for robust time‐variant model parameterization and continuous improvement of emissions factors to enhance the precision of emission inventories. Additionally, urgent mitigation is required, as all available inventories indicate a rapid increase in global N2O emissions from livestock manure in recent decades. [ABSTRACT FROM AUTHOR]

Microbial communities that reduce nitrous oxide (N2O) are divided into two clades, nosZI and nosZII. These clades significantly differ in their ecological niches and their implications for N2O emissions in terrestrial environments. However, our understanding of N2O reducers in aquatic systems is currently limited. This study investigated the relative abundance and diversity of nosZI‐ and nosZII‐type N2O reducers in rivers and their impact on N2O emissions. Our findings revealed that stream sediments possess a high capacity for N2O reduction, surpassing N2O production under high N2O/NO3‐ ratio conditions. This study, along with others in freshwater systems, demonstrated that nosZI marginally dominates more often in rivers. While microbes containing either nosZI and nosZII were crucial in reducing N2O emissions, the net contribution of nosZII‐containing microbes was more significant. This can be attributed to the nir gene co‐occurring more frequently with the nosZI gene than with the nosZII gene. The diversity within each clade also played a role, with nosZII species being more likely to function as N2O sinks in streams with higher N2O concentrations. Overall, our findings provide a foundation for a better understanding of the biogeography of stream N2O reducers and their effects on N2O emissions. [ABSTRACT FROM AUTHOR]

While ammonia (NH 3) and hydrogen (H 2) are promising carbon-free fuels, there are significant challenges presented by their combustion properties. Blending them can help mitigate some of these issues; however, the fundamental behaviors of these blends need to be well understood. A constant volume combustion chamber (CVCC) is used to study the emissions of nitrogen oxides (NO, NO 2 , N 2 O), laminar burning velocity (LBV), and intrinsic instabilities for H 2 -NH 3 blends across a wide range of equivalence ratios (Φ = 0.5 to 1.5) and volume fractions of H 2 in the blends (0% to 50%). Measurements of LBV are consistent with existing data where available. The largest NO x and N 2 O emissions are found at lean conditions and decrease significantly for rich mixtures. NO x emissions tend to increase with H 2 fractions in fuel for lean mixtures. Intrinsic instabilities are more prominent at lean conditions and heavily influenced by the amount of H 2 in the blend. [Display omitted] • NO x production peaks at Φ =0.7, increases with H 2 content for lean mixtures. • N 2 O production peaks at lowest Φ , no significant variation with H 2 content. • Higher H 2 content results in earlier and more pronounced flame wrinkling. • LBV and emissions data extends available range for mechanism validation. [ABSTRACT FROM AUTHOR]

Using the IMK–IAA data processor, methane and nitrous oxide distributions were retrieved from version-8 limb emission spectra recorded with the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). The dataset includes measurements from the nominal, upper troposphere–lower stratosphere, middle-atmosphere, upper-atmosphere and noctilucent-cloud observation modes. The processing differs from the previous version-5 data with respect to the atmospheric state variables that are jointly retrieved along with the target gases CH 4 and N 2 O, the treatment of the radiance offset, the selection of microwindows, the regularization, the spectroscopic data used and the treatment of horizontal variability of the atmospheric state. Besides the regular data product, a coarse-grid representation of the profiles with unity averaging kernels is available, as well as a specific research product for middle-atmosphere measurements resulting from a slightly different retrieval approach. The CH 4 errors are dominated by the large spectroscopic uncertainty for line intensities, which probably is too pessimistic, and estimated to be 21 %–34 % in the altitude range 6–68 km for northern midlatitude summer day conditions. The N 2 O errors are 7 %–17 % below 45 km. At higher altitudes they increase strongly due to nearly vanishing N 2 O amounts. Analysis of the horizontal averaging kernels reveals that for both gases the horizontal resolution is sampling-limited; i.e., information is not smeared over consecutive limb scans. Zonal-mean seasonal composites of both CH 4 and N 2 O exhibit the typical distribution of source gases with strong upwelling in the tropics and subsidence above the winter poles. Comparison with the previous data version shows several improvements: first, the vertical resolution of the retrieved CH 4 (N 2 O) profiles has generally been significantly enhanced and varies between 2.5 (2.5) and 4 (5) km at altitudes between 10 and 60 km, with the best resolution around 30 km for both species. Secondly, the number of non-converged retrievals has been clearly reduced, and thirdly, formerly strongly oscillating profiles are now considerably smoother. [ABSTRACT FROM AUTHOR]

Nitrous oxide inhalation for intrapartum maternal analgesia was associated with a lower likelihood of neonatal intensive care unit admission but with increased risk of neonatal hyperbilirubinemia. OBJECTIVE: To evaluate the association between intrapartum nitrous oxide use and adverse short-term neonatal outcomes. METHODS: This was a retrospective cohort study of individuals with singleton gestations at 35 or more weeks who attempted labor and delivered at an academic hospital between June 1, 2015, and February 28, 2020. Data were extracted from the electronic medical record using billing and diagnostic codes. Patients were classified based on whether they received no intrapartum analgesia or received nitrous oxide only. Those who received other analgesia types were excluded. The primary outcome was neonatal intensive care unit (NICU) admission. Secondary outcomes included Apgar score less than 7 at 1 minute and 5 minutes, respiratory composite outcome (including meconium aspiration syndrome, neonatal bronchopulmonary disorders, neonatal transient tachypnea, and other neonatal respiratory distress that required NICU admission), hypoglycemia, and hyperbilirubinemia. Univariable and multivariable analyses were used to estimate the association between nitrous oxide exposure intrapartum and the selected outcomes. RESULTS: Of 6,047 included, 4,153 (68.7%) received no analgesia, and 1,894 (31.3%) received nitrous oxide only. In comparison with individuals who received no analgesia, those who received nitrous oxide were more likely to be nulliparous, be of Black racial identity, have noncommercial insurance, and be less likely to deliver by intrapartum cesarean. The reception of nitrous oxide, compared with the reception of no analgesia, was associated with a lower likelihood of NICU admission (6.4% vs 8.1%; adjusted odds ratio [aOR] 0.77, 95% CI, 0.62–0.96) and an increased likelihood of neonatal hyperbilirubinemia (aOR 1.23, 95% CI, 1.08–1.41). Inhaled nitrous oxide exposure, in comparison with the reception of no analgesia, was not associated with the other secondary outcomes, including Apgar score less than 7 at 1 minute (odds ratio [OR] 0.74, 95% CI, 0.50–1.10) or 5 minutes (OR 0.91, 95% CI, 0.32–2.60), respiratory composite outcome (OR 0.91, 95% CI, 0.70–1.17), and hypoglycemia (OR 0.82, 95% CI, 0.64–1.05). CONCLUSION: In this single-center retrospective cohort of low-risk patients, intrapartum inhaled nitrous oxide, compared with the reception of no analgesia, was associated with a decreased risk for NICU admission but with an increased risk for hyperbilirubinemia; other outcomes did not differ. These findings may be used to counsel patients when considering nitrous oxide for labor analgesia. [ABSTRACT FROM AUTHOR]

Nitrous oxide, an inhalational anaesthetic, is popular with adolescents worldwide as an accessible recreational drug which induces a euphoric effect. However, chronic abuse leads to serious complications such as myeloneuropathy and bone marrow suppression by inactivation of vitamin B12. A 17-year-old girl presented with nitrous oxide-induced myeloneuropathy. She reported chronic nitrous oxide inhalation for 10 months and was admitted to the emergency department on account of repeated falls for 2 weeks. She also had ascending paraesthesia in both legs and urinary incontinence. Neurological examination demonstrated bilateral lower extremity weakness [motor power: proximal muscles 4/5, plantar flexion and extensor hallucis longus (EHL) 3/5], decreased sensation, proprioception and vibration of the lower extremities. Deep tendon reflexes were absent in the ankles and knees. Laboratory results demonstrated mild anaemia [Hb 11.2 g/dL (12.0–16.0), haematocrit 35.4% (36–50), MCV 89.4 fl (78–102)] with significant hypersegmented neutrophils in a peripheral blood smear. Serum vitamin B12 was 340 pg/mL (197–771), but serum homocysteine was increased at 65.8 µmol/L (5–15). A nerve conduction study was prolonged, and F-waves were absent from the bilateral perineal and tibial nerves, indicating diffuse demyelinating motor polyneuropathy. Magnetic resonance imaging of the whole spine demonstrated faint T2 hypersignal intensity and an inverted V-shape appearance at the posterior column of the upper thoracic cord (around T2–T6), a pathognomonic sign of vitamin B12 deficiency or subacute combined degeneration of the nitrous oxide-induced myeloneuropathy. A 7-day course of 1000 µg cyanocobalamin was given intramuscularly, followed by weekly doses for 4 weeks. Supplements of daily oral vitamin B1, B6 and B12 (65 µg vitamin B12) were administered, along with rehabilitation. At the 6-months outpatient follow-up, there were a few residual neurological abnormalities: weakness of the left EHL (grade 4/5) and an absent deep tendon reflex in the left ankle. This case emphasises the significant health consequences of chronic abuse of nitrous oxide, myeloneuropathy and megaloblastic anaemia, by inactivation of vitamin B12. The myelopathy is noticeably improved by cyanocobalamin.Abbreviations: EHL: extensor hallucis longus; MRI: magnetic resonance imaging; NCS: nerve conduction study [ABSTRACT FROM AUTHOR]

Castellaniella species have been isolated from a variety of mixed-waste environments including the nitrate and multiple metal-contaminated subsurface at the Oak Ridge Reservation (ORR). Previous studies examining microbial community composition and nitrate removal at ORR during biostimulation efforts reported increased abundances of members of the Castellaniella genus concurrent with increased denitrification rates. Thus, we asked how genomic and abiotic factors control the Castellaniella biogeography at the site to understand how these factors may influence nitrate transformation in an anthropogenically impacted setting. We report the isolation and characterization of several Castellaniella strains from the ORR subsurface. Five of these isolates match at 100% identity (at the 16S rRNA gene V4 region) to two Castellaniella amplicon sequence variants (ASVs), ASV1 and ASV2, that have persisted in the ORR subsurface for at least 2 decades. However, ASV2 has consistently higher relative abundance in samples taken from the site and was also the dominant blooming denitrifier population during a prior biostimulation effort. We found that the ASV2 representative strain has greater resistance to mixed metal stress than the ASV1 representative strains. We attribute this resistance, in part, to the large number of unique heavy metal resistance genes identified on a genomic island in the ASV2 representative genome. Additionally, we suggest that the relatively lower fitness of ASV1 may be connected to the loss of the nitrous oxide reductase (nos) operon (and associated nitrous oxide reductase activity) due to the insertion at this genomic locus of a mobile genetic element carrying copper resistance genes. This study demonstrates the value of integrating genomic, environmental, and phenotypic data to characterize the biogeography of key microorganisms in contaminated sites. [ABSTRACT FROM AUTHOR]

[Display omitted] • Acidification, coverage, microbe N conversion, adsorption combined for NH 3 reduction. • Rich H 2 SO 4 and sulfate remained on the vermiculite (VM) after 5 M H+ modification. • Giant CO 2 bubbles due to initial slurry acidification promoted the cover floating. • Vermiculite after 5 M H+ modification performed highest NH 3 reduction (68 %). • NH 4 +/ NH 3 adsorption by VM contributed little (4.7%) to the overall NH 3 mitigation. Animal slurry storage is an important ammonia (NH 3) emission source. Sulfuric acid (H 2 SO 4)-modified vermiculite coverage is a new promising technology for controlling NH 3 emission from slurry storage. However, the underlying mechanisms in controlling the mitigation effect remain unclear. Here, a series of experiments to determine the effect of H 2 SO 4 on the modified vermiculite properties, floating persistence, and NH 3 mitigation effect was conducted. Results showed that abundant H 2 SO 4 and sulfate remained on the outer surface and in the extended inner pores of the vermiculite with acidifying H+ concentrations higher than 5 M. An initial strong instantaneous acidification of surface slurry released rich carbon dioxide bubbles, strengthening cover floating performance. An acidification in the vermiculite cover layer and a good coverage inhibition interacted, being the two leading mechanisms for mitigating NH 3 during initial 40–50 days of storage. The bacterial-amoA gene dominated the conversion of NH 3 to nitrous oxide after 50 days of storage. Vermiculite with 5 M H+ modification reduced the NH 3 emissions by 90 % within the first month of slurry storage and achieved a 64 % mitigation efficiency throughout the 84 days period. With the development of the aerial spraying equipment such as agricultural drones, acidifying vermiculite coverage hold promise as an effective method for reducing NH 3 emission while absorbing nutrients from liquid slurry storage tank or lagoon. This design should now be tested under field conditions. [ABSTRACT FROM AUTHOR]

• Community composting was systematically studied in terms of atmospheric emissions. • Ammonia, methane, nitrous oxide, VOC and odours were measured in several sites. • Community compost presents a good quality, especially in terms of stability. • VOC families were diverse, although terpenes were the predominant compounds. • The age of the material and turning dramatically affects gaseous emissions. Composting has demonstrated to be an effective and sustainable technology to valorise organic waste in the framework of circular economy, especially for biowaste. Composting can be performed in various technological options, from full-scale plants to community or even individual composters. However, there is scarce scientific information about the potential impact of community composting referred to gaseous emissions. This work examines the emissions of methane and nitrous oxide as main GHG, ammonia, VOC and odours from different active community composting sites placed in Spain, treating kitchen, leftovers and household biowaste. Expectedly, the gaseous emissions have an evident relation with the composting progress, represented mainly by its decrease as temperature or biological activity decreases. GHG and odour emission rates ranged from 5.3 to 815.2 mg CO 2eq d-1 kg-1VS and from 69.8 to 1088.5 ou d-1 kg-1VS, respectively, generally being lower than those find in open-air full-scale composting. VOC characterization from the community composting gaseous emissions showed a higher VOC families' distribution in the emissions from initial composting phases, even though terpenes such as limonene, α-pinene and β-pinene were the most abundant VOC along the composting process occurring in the different sites studied. The results presented in this study can be the basis to evaluate systematically and scientifically the numerous current projects for a worldwide community composting implementation in decentralised biowaste management schemes. [ABSTRACT FROM AUTHOR]

Agricultural production, including animal husbandry, is associated with greenhouse gas (GHG) emissions, which have a negative impact on the environment. The purpose of this study was to determine methane and nitrous oxide emissions at the level of individual farms and to identify differences in emissions by type of production. Analyses were conducted using data from the FADN agricultural accounting system, covering the farms in Poland engaged in dairy production and the breeding of other grazing livestock for the period from 2012 to 2021. The relationships and trends of the indicators during the study period were also analyzed. The statistical analysis confirmed the relationship between greenhouse gas emissions and economic performance. In the case of dairy farms, the emissions averaged 137.09 kg·ha−1 of methane and 94.05 kg·ha−1 of nitrous oxide, which were found to increase as the net-added value and farm income increased. The results of the presented research highlight the existence of a link between economic goals and GHG emissions, which is an important contribution to the development of mitigation strategies in livestock production. [ABSTRACT FROM AUTHOR]

Within oxygen minimum zones, anaerobic processes transform bioavailable nitrogen (N) into the gases dinitrogen (N2) and nitrous oxide (N2O), a potent greenhouse gas. Mesoscale eddies in these regions create heterogeneity in dissolved N tracers and O2 concentrations, influencing nonlinear N cycle reactions that depend on them. Here, we use an eddy‐resolving model of the Eastern Tropical South Pacific to show that eddies enhance N2 production by between 43% and 64% at the expense of reducing N2O production by between 94% and 104% due to both the steep increase of progressive denitrification steps at vanishing oxygen, and the more effective inhibition of N2O consumption relative to production. Our findings reveal the critical role of eddies in shaping the N cycle of oxygen minimum zones, which is not currently represented by coarse models used for climate studies. Plain Language Summary: Nitrogen limits photosynthesis over large swaths of the ocean. Oxygen minimum zones are important oceanic environments where the presence of low O2 concentrations allow anaerobic microbial communities to transform bioavailable forms of nitrogen into the gases dinitrogen (N2) and nitrous oxide (N2O, a powerful greenhouse gas), which together lead to nitrogen loss from the oceans. The large scale ocean circulation acts to maintain these oxygen minimum zones, and the gradients in nitrogen and oxygen concentrations surrounding them. Turbulence also generates eddies and filaments which stir these gradients, promoting chemical heterogeneity. However, it is uncertain how eddies impact the nitrogen transformation rates dependent on nitrogen and oxygen tracer concentrations. Using a high resolution ocean model of the Eastern Tropical South Pacific oxygen minimum zone, we explore the contributions from eddies to total N2 and N2O production. We highlight that roughly half of total N2 production is caused by the presence of eddies, while N2O production is drastically reduced or even consumed. These findings expand our understanding of the ways in which eddies alter nitrogen loss from the oceans, and challenge the ability of non‐eddy resolving models to accurately represent N2 and N2O production in a changing ocean. Key Points: A high resolution model is used to estimate the effect of mesoscale eddies on the N cycle in a major oxygen minimum zoneEddies simultaneously enhance fixed N loss and suppress nitrous oxide productionThese eddy effects result from the progressive inhibition of the denitrification steps by oxygen concentrations [ABSTRACT FROM AUTHOR]

Cover cropping is a promising strategy to improve soil health, but it may also trigger greenhouse gas emissions, especially nitrous oxide (N2O). Beyond nitrogen (N) availability, cover crop residue decomposition may accelerate heterotrophic respiration to limit soil O2 availability, hence promote N2O emissions from denitrification under sub-optimal water-filled pore space (WFPS) conditions that are typically not conducive to large N2O production. We conducted a 21-day incubation experiment to examine the effects of contrasting cover crop residue (grass vs legume) decomposition on soil O2 and biogeochemical changes to influence N2O and CO2 emissions from 15N labeled fertilized soils under 50% and 80% WFPS levels. Irrespective of cover crop type, mixing cover crop residue with N fertilizer resulted in high cumulative N2O emissions under both WFPS conditions. In the absence of cover crop residues, the N fertilizer effect of N2O was only realized under 80% WFPS, whereas it was comparable to the control under 50% WFPS. The N2O peaks under 50% WFPS coincided with soil O2 depletion and concomitant high CO2 emissions when cover crop residues were mixed with N fertilizer. While N fertilizer largely contributed to the total N2O emissions from the cover crop treatments, soil organic matter and/or cover crop residue derived N2O had a greater contribution under 50% than 80% WFPS. Our results underscore the importance of N2O emissions from cover crop-based fertilized systems under relatively lower WFPS via a mechanism of respiration-induced anoxia and highlight potential risks of underestimating N2O emissions under sole reliance on WFPS. [ABSTRACT FROM AUTHOR]

Background Methods Results Conclusions Nitrous oxide use is shifting from general anesthesia to sedation and pain control. Interest in novel uses of nitrous oxide in psychiatry is also growing. Thus, understanding the consequences of using nitrous oxide remains relevant. Previous quantitative research might not have fully captured the whole spectrum of nitrous oxide, whereas qualitative analysis can provide a more comprehensive description. This qualitative study aims to describe the subjective experiences of nitrous oxide use in healthy volunteers who have no prior history of recreational substance misuse.Twenty healthy male volunteers inhaled 50% nitrous oxide for 20 min. Females were excluded due to higher incidence of nausea with nitrous oxide. Afterwards, all participants answered an open‐ended question about their experiences during sedation. The answers were then analyzed with inductive qualitative content analysis to identify emergent subcategories, categories, and overarching themes.We identified two themes: nitrous oxide is mind‐altering and produces sensory overload. The mind‐altering properties were represented by dreamlike states and heightened emotions. Dreamlike states comprised changes in consciousness and scary, bizarre, or transcendental dreams. Pleasant dreams were not reported. Heightened emotions included euphoria, anxiety, and fear of losing control. Sensory overload consists of distorted perception, bodily sensations, and a heightened sense of surroundings.Experiences under nitrous oxide sedation are extremely variable and not always pleasant. These findings can improve our understanding of the likes/dislikes of patients undergoing nitrous oxide sedation. Further qualitative studies should focus on the experiences of other groups, such as children or women in labor. [ABSTRACT FROM AUTHOR]

Improving the selectivity in the oxidative coupling of methane to ethane/ethylene poses a significant challenge for commercialization. The required improvements are hampered by the uncertainties associated with the reaction mechanism due to its complexity. Herein, we report about 90 % selectivity to the target products at 11 % methane conversion over Gd2O3‐based catalysts at 700 °C using N2O as the oxidant. Sophisticated kinetic studies have suggested the nature of adsorbed oxygen species and their binding strength as key parameters for undesired methane oxidation to carbon oxides. These descriptors can be controlled by a metal oxide promoter for Gd2O3. [ABSTRACT FROM AUTHOR]

Copper-containing nitrous oxide reductase catalyzes a 2-electron reduction of the green-house gas N2O to yield N2. It contains two metal centers, the binuclear electron transfer site CuA, and the unique, tetranuclear CuZ center that is the site of substrate binding. Different forms of the enzyme were described previously, representing variations in oxidation state and composition of the metal sites. Hypothesizing that many reported discrepancies in the structural data may be due to radiation damage during data collection, we determined the structure of anoxically isolated Marinobacter nauticus N2OR from diffraction data obtained with low-intensity X-rays from an in-house rotating anode generator and an image plate detector. The data set was of exceptional quality and yielded a structure at 1.5 Å resolution in a new crystal form. The CuA site of the enzyme shows two distinct conformations with potential relevance for intramolecular electron transfer, and the CuZ cluster is present in a [4Cu:2S] configuration. In addition, the structure contains three additional types of ions, and an analysis of anomalous scattering contributions confirms them to be Ca2+, K+, and Cl–. The uniformity of the present structure supports the hypothesis that many earlier analyses showed inhomogeneities due to radiation effects. Adding to the earlier description of the same enzyme with a [4Cu:S] CuZ site, a mechanistic model is presented, with a structurally flexible CuZ center that does not require the complete dissociation of a sulfide prior to N2O binding. The [4Cu:2S] CuZ site in M. nauticus N 2O reductase. The electron density map shown is contoured at the 5 σ level, highlighting the presence of two sulfide ligands. 705x677mm (72 x 72 DPI) [ABSTRACT FROM AUTHOR]

Peatlands play a crucial role in the global carbon (C) cycle, making their restoration a key strategy for mitigating greenhouse gas (GHG) emissions and retaining C. This study analyses the most common restoration pathways employed in boreal and temperate peatlands, potentially applicable in tropical peat swamp forests. Our analysis focuses on the GHG emissions and C retention potential of the restoration measures. To assess the C stock change in restored (rewetted) peatlands and afforested peatlands with continuous drainage, we adopt a conceptual approach that considers short-term C capture (GHG exchange between the atmosphere and the peatland ecosystem) and long-term C sequestration in peat. The primary criterion of our conceptual model is the capacity of restoration measures to capture C and reduce GHG emissions. Our findings indicate that carbon dioxide (CO2) is the most influential part of long-term climate impact of restored peatlands, whereas moderate methane (CH4) emissions and low N2O fluxes are relatively unimportant. However, lateral losses of dissolved and particulate C in water can account up to a half of the total C stock change. Among the restored peatland types, Sphagnum paludiculture showed the highest CO2 capture, followed by shallow lakes and reed/grass paludiculture. Shallow lakeshore vegetation in restored peatlands can reduce CO2 emissions and sequester C but still emit CH4, particularly during the first 20 years after restoration. Our conceptual modelling approach reveals that over a 300-year period, under stable climate conditions, drained bog forests can lose up to 50% of initial C content. In managed (regularly harvested) and continuously drained peatland forests, C accumulation in biomass and litter input does not compensate C losses from peat. In contrast, rewetted unmanaged peatland forests are turning into a persistent C sink. The modelling results emphasized the importance of long-term C balance analysis which considers soil C accumulation, moving beyond the short-term C cycling between vegetation and the atmosphere. [ABSTRACT FROM AUTHOR]

The greenhouse gas (GHG) emissions of spring cereal monoculture under long-term conventional tillage (CT) and no-till (NT) treatment established in 2018 were measured in a peatland in Southwestern Finland during the period 2018–2021. Nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) fluxes were measured with chambers approximately every two weeks throughout the period under study. Net ecosystem exchange was measured during the growing seasons, and hourly ecosystem respiration (ER) and gross photosynthesis (GP) were modelled with empirical models. Across the whole period, annual emissions were 6.8 ± 1.2 and 5.7 ± 1.2 Mg CO2–C ha −1 yr−1 (net ecosystem carbon balance), 8.8 ± 2.0 and 7.1 ± 2.0 kg N2O–N ha−1 yr−1, and − 0.43 ± 0.31 and − 0.40 ± 0.31 kg CH4-C ha−1 yr−1 for CT and NT, respectively. The global warming potential was lower in NT (p = 0.045), and it ranged from 26 to 34 Mg CO2 eq. ha−1 yr−1 in CT and from 19 to 31 Mg CO2 eq. ha−1 yr−1 in NT. The management effect on the rates of single GHGs was not consistent over the years. Higher GP was found in CT in 2019 and in NT in 2020. Differences in ER between treatments occurred mostly outside the growing season, especially after ploughing, but the annual rates did not differ statistically. NT reduced the N2O emissions by 31% compared to CT in 2020 (p = 0.044) while there were no differences between the treatments in other years. The results indicate that NT may have potential to reduce slightly CO2 and N2O emissions from cultivated peat soil, but the results originate from the first three years after a management change from CT to NT, and there is still a lack of long-term results on NT on cultivated peat soils. [ABSTRACT FROM AUTHOR]

Drained agricultural peatlands occupy only 1% of agricultural land but are estimated to be responsible for approximately one third of global cropland greenhouse gas emissions. However, recent studies show that greenhouse gases fluxes from agricultural peatlands can vary by orders of magnitude over time. The relationship between these hot moments (individual fluxes with disproportionate impact on annual budgets) of greenhouse gas emissions and individual chamber locations (i.e. hot spots with disproportionate observations of hot moments) is poorly understood, but may help elucidate patterns and drivers of high greenhouse gas emissions from agricultural peatland soils. We used continuous chamber-based flux measurements across three land uses (corn, alfalfa, and pasture) to quantify the spatiotemporal patterns of soil greenhouse gas emissions from temperate agricultural peatlands in the Sacramento-San Joaquin Delta of California. We found that the location of hot spots of emissions varied over time and were not consistent across annual timescales. Hot moments of nitrous oxide (N2O) and carbon dioxide (CO2) fluxes were more evenly distributed across space than methane (CH4). In the corn system, hot moments of CH4 flux were often isolated to a single location but locations were not consistent across years. Spatiotemporal variability in soil moisture, soil oxygen, and temperature helped explain patterns in N2O fluxes in the annual corn agroecosystem but were less informative for perennial alfalfa N2O fluxes or CH4 fluxes across ecosystems, potentially due to insufficient spatiotemporal resolution of the associated drivers. Overall, our results do not support the concept of persistent hot spots of soil CO2, CH4, and N2O emissions in these drained agricultural peatlands. Hot moments of high flux events generally varied in space and time and thus required high sample densities. Our results highlight the importance of constraining hot moments and their controls to better quantify ecosystem greenhouse gas budgets. [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHGs) emissions from peatlands contribute significantly to ongoing climate change because of human land use. To develop reliable and comprehensive estimates and predictions of GHG emissions from peatlands, it is necessary to have GHG observations, including carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), that cover different peatland types globally. We synthesize published peatland studies with field GHG flux measurements to identify gaps in observations and suggest directions for future research. Although GHG flux measurements have been conducted at numerous sites globally, substantial gaps remain in current observations, encompassing various peatland types, regions and GHGs. Generally, there is a pressing need for additional GHG observations in Africa, Latin America and the Caribbean regions. Despite widespread measurements of CO2 and CH4, studies quantifying N2O emissions from peatlands are scarce, particularly in natural ecosystems. To expand the global coverage of peatland data, it is crucial to conduct more eddy covariance observations for long-term monitoring. Automated chambers are preferable for plot-scale observations to produce high temporal resolution data; however, traditional field campaigns with manual chamber measurements remain necessary, particularly in remote areas. To ensure that the data can be further used for modeling purposes, we suggest that chamber campaigns should be conducted at least monthly for a minimum duration of one year with no fewer than three replicates and measure key environmental variables. In addition, further studies are needed in restored peatlands, focusing on identifying the most effective restoration approaches for different ecosystem types, conditions, climates, and land use histories. [ABSTRACT FROM AUTHOR]

Despite the documented increase in greenhouse gas (GHG) emissions from Southeast Asian peat swamp forest degradation and conversion to oil palm over recent decades, reliable estimates of emissions of nitrous oxide (N2O) and methane (CH4) are lacking. We measured soil fluxes of N2O and CH4 and their environmental controls along a peatland transition from primary forest (PF) to degraded drained forest (DF) to oil palm plantation (OP) over 18 months in Jambi, Sumatra, Indonesia. Sampling was conducted monthly at all sites and more intensively following two fertilization events in the OP. Mean annual emissions of N2O (kg N ha−1 yr−1) were 1.7 ± 0.2 for the PF, 2.3 ± 0.2 for the DF and for the OP 8.1 ± 0.8 without drainage canals (DC) and 7.7 ± 0.7 including DC. High N2O emissions in the OP were driven by peat decomposition, not by N fertilizer addition. Mean CH4 annual fluxes (kg C ha−1 yr−1) were 8.2 ± 1.9 for the PF, 1.9 ± 0.4 for the DF, and 1.6 ± 0.3 for the OP with DC and 1.1 ± 0.2 without. Considering their 20-year global warming potentials (GWP), the combined non-CO2 GHG emission (Mg CO2-equivalent ha−1 yr−1) was 3.3 ± 0.6 for the PF and 1.6 ± 0.2 for the DF. The emission in the OP (3.8 ± 0.3 with or without DC) was similar to the PF because reductions in CH4 emissions offset N2O increases. However, considering 100-year GWP, the combined non-CO2 GHG emission was larger in the OP (3.4 ± 0.3 with DC and 3.5 ± 0.3 without) compared to both the PF and the DF (1.5 ± 0.2 and 1.2 ± 0.1, respectively). The increase in peat N2O emissions associated with the land-use change transition from primary forest to oil palm plantation at our sites provides further evidence of the urgent need to protect tropical peat swamp forests from drainage and conversion. [ABSTRACT FROM AUTHOR]

Small rhizosphere exudates as chemical signals provide a green strategy to reduce nitrogen emissions and promote low-carbon agriculture. Specific biological nitrification inhibitors (BNIs) and biological denitrification inhibitors (BDIs) could retard nitrification and denitrification, thus reducing N 2 O emissions from terrestrial ecosystems. Enhanced nitrogen removal rates and lower N 2 O emissions are achieved by biological denitrification promoters (BDPs), such as root-derived fatty acid amides and sterols, and microbe-derived N -acyl-homoserine lactones (AHLs) in aquatic environments. Cultivating BNI/BDI/BDP-enhanced plant varieties, intercropping and rotation with BNI/BDI plants, developing green nitrogen fertilizers, and designing water purification bioagents based on small rhizosphere exudates are promising application measures for supporting green low-carbon agriculture. Low-carbon approaches to agriculture constitute a pivotal measure to address the challenge of global climate change. In agroecosystems, rhizosphere exudates are significantly involved in regulating the nitrogen (N) cycle and facilitating belowground chemical communication between plants and soil microbes to reduce direct and indirect emissions of greenhouse gases (GHGs) and control N runoff from cultivated sites into natural water bodies. Here, we discuss specific rhizosphere exudates from plants and microorganisms and the mechanisms by which they reduce N loss and subsequent N pollution in terrestrial and aquatic environments, including biological nitrification inhibitors (BNIs), biological denitrification inhibitors (BDIs), and biological denitrification promoters (BDPs). We also highlight promising application scenarios and challenges in relation to rhizosphere exudates in terrestrial and aquatic environments. [ABSTRACT FROM AUTHOR]

Surface drip fertigation has demonstrated promising results regarding the mitigation of nitrous oxide (N2O) emissions. The use of subsurface irrigation may offer the possibility of reducing these emissions further due to the modification of the soil moisture profile and N allocation, both of which affect the biochemical processes leading to N2O fluxes. However, the mitigation potential of subsurface irrigation combined with different mineral nitrogen (N) fertilizers (ammonium or nitrate-based, use of nitrification inhibitors) still needs to be evaluated. To respond to this need, a 2-year field experiment was set up in central Spain to test two different drip-fertigation systems (surface and subsurface at 30 cm depth) and four N fertilization treatments (control, calcium nitrate, and ammonium sulfate with or without the nitrification inhibitor 3,4-dimethylpyrazole phosphate, DMPP) in an irrigated maize (Zea mays L.) crop. Nitrous oxide emissions, mineral N concentrations (ammonium, NH4+, and nitrate, NO3−), and abundance of key N genes involved in nitrification and denitrification processes were measured in two soil layers (0–20 and 20–40 cm). Regardless of the irrigation system, ammonium sulfate gave the highest cumulative N2O losses in both campaigns, while calcium nitrate and the use of DMPP were the most effective strategies to abate N2O fluxes in the first and second years, respectively. Differences between irrigation systems were not statistically significant for cumulative N2O emissions, despite the clear effect on topsoil mineral N (higher NH4+ and NO3− concentrations in surface and subsurface drip, respectively). Nitrous oxide emissions were positively correlated with soil NH4+ concentrations. Gene abundances were not a trustworthy predictor of N2O losses in the 1st year, although a clear inhibitory effect of fertilization on microbial communities (i.e., ammonia oxidizers, nitrite reducers, and N2O reducers) was observed during this campaign. During the second year, nitrifying and denitrifying genes were affected by irrigation (with higher abundances in the 20–40 cm layer in subsurface than in surface drip) and by the addition of DMPP (which had a detrimental effect on gene abundances in both irrigation systems that disappeared after the fertigation period). In conclusion, the use of DMPP or calcium nitrate instead of ammonium sulfate may enhance the chances for an additional mitigation in both surface and subsurface irrigation systems. [ABSTRACT FROM AUTHOR]

Objective: To compare the carbon footprint of caesarean and vaginal birth. Design: Life cycle assessment (LCA). Setting: Tertiary maternity units and home births in the UK and the Netherlands. Population: Birthing women. Methods: A cradle‐to‐grave LCA using openLCA software to model the carbon footprint of different modes of delivery in the UK and the Netherlands. Main Outcome Measures: 'Carbon footprint' (in kgCO2 equivalents [kgCO2e]). Results: Excluding analgesia, the carbon footprint of a caesarean birth in the UK was 31.21 kgCO2e, compared with 12.47 kgCO2e for vaginal birth in hospital and 7.63 kgCO2e at home. In the Netherlands the carbon footprint of a caesarean was higher (32.96 kgCO2e), but lower for vaginal birth in hospital and home (10.74 and 6.27 kgCO2e, respectively). Emissions associated with analgesia for vaginal birth ranged from 0.08 kgCO2e (with opioid analgesia) to 237.33 kgCO2e (nitrous oxide with oxygen). Differences in analgesia use resulted in a lower average carbon footprint for vaginal birth in the Netherlands than the UK (11.64 versus 193.26 kgCO2e). Conclusion: The carbon footprint of a caesarean is higher than for a vaginal birth if analgesia is excluded, but this is very sensitive to the analgesia used; use of nitrous oxide with oxygen multiplies the carbon footprint of vaginal birth 25‐fold. Alternative methods of pain relief or nitrous oxide destruction systems would lead to a substantial improvement in carbon footprint. Although clinical need and maternal choice are paramount, protocols should consider the environmental impact of different choices. [ABSTRACT FROM AUTHOR]

To facilitate the data analysis of current and future high-resolution space telescope missions, we adopt 'Best Theory + Reliable High-resolution Experiment' (BTRHE) strategy to develop highly accurate infrared line lists for nitrous oxide (N2O). The 'Ames-1' potential energy surface (PES) is a CCSD(T)/aug-cc-pVQZ PES refined using selected HITRAN experimental data, with σrms = 0.02–0.03 cm-1 for five isotopologues. The 'Ames-1' dipole moment surface (DMS) is fitted from CCSD(T)/aug-cc-pV(T,Q,5)Z dipoles extrapolated to one electron basis set limit. Using the Ames-1 PES and DMS, Ames-296K line lists are computed in the full range of 0–15,000 cm-1 for 12 N2O isotopologues, with S296K ≥ 10−31 cm-1/molecule.cm-2. The reliability and consistency of Ames-296K intensity predictions (SAmes) are demonstrated through comparisons with HITRAN (SHITRAN), NOSL-296 (SNOSL), recent observed intensities (Sobs) and Effective Dipole Model (EDM) intensities (SEDM). Agreements and discrepancies are discussed, along with preliminary uncertainty estimate for SAmes. The SAmes provides a good constraint to prevent substantial errors in intensity predictions (e.g. for weak bands and minor isotopologues) and can be further improved. Ames-296K and NOSL-296 may complement each other to provide improved input for future database updates, combining the strengths of EH/EDM and BTRHE approaches. Data available at and https://doi.org/10.48667/9kmk-0334. [ABSTRACT FROM AUTHOR]

In this work, a previously developed three-feature Artificial Neural Network (ANN) model with dimensional inputs is directly applied to predict the cell size of hydrocarbon/ammonia/nitrous oxide mixtures and compare these to experimental data. This model uses as inputs three ZND parameters (MCJ, ΔI, and σ ˙ max ), which are mainly calculated using Konnov's and Mével's mechanisms. A similar prediction is obtained with the two mechanisms for the biogas–O2, H2–O2, H2–N2O, and NH3–O2 mixtures, indicating that the model is not only limited to Konnov's chemical kinetic mechanism which was used for its training. The overall good agreement between the ANN predictions and the actual experimental values for the aforementioned mixtures, which are not used in the original training of the ANN model, is promising and shows its potential for application and extension to other mixtures and initial conditions, provided that the chemical kinetic parameters describing the ideal reaction zone structure could be computed. The model is then used to compare experimental cell size data from two detonation tube facilities, and also different chemical kinetic mechanisms for NH3-N2O mixtures. In the end, the original ANN model is expanded with the inclusion of additional cell size data, showing a slightly lower mean error for the predicted cell sizes if the data for the mixtures considered in this study are taken into account for the training of the new ANN model. [ABSTRACT FROM AUTHOR]