Addition of iron does not ameliorate sulfide toxicity by sargassum influx to mangroves but dampens methane and nitrous oxide emissions.

Sargassum spp. strandings in the tropical Atlantic harm local ecosystems due to toxic sulfide levels. We conducted a mesocosm experiment to test the efficacy of iron(III) (hydr)oxides in (a) mitigating sulfide toxicity in mangroves resulting from Sargassum and (b) reducing potentially enhanced greenhouse gas emissions. Our results show that iron addition failed to prevent mangrove mortality caused by highly toxic sulfide concentrations, which reached up to 15,000 µmol l-1 in 14 days; timely removal may potentially prevent mangrove death. Sargassum-impacted mesocosms significantly increased methane, nitrous oxide, and carbon dioxide emissions, producing approximately 1 g CO2-equivalents m-2 h-1 during daylight hours, thereby shifting mangroves from sinks to sources of greenhouse gasses. However, iron addition decreased methane emissions by 62 % and nitrous oxide emissions by 57 %. This research reveals that Sargassum strandings have multiple adverse effects related to chemical and ecological dynamics in mangrove ecosystems, including greenhouse gas emissions.

Potential water repellency influenced CO2 and CH4 release from moist soils: Experiments on water-repellent Japanese Andosols.

Soil, the largest terrestrial carbon (C) pool on earth is an important source of greenhouse gasses. Soil water repellency (SWR), a moisture-dependent characteristic, is an important factor that affects microbial decomposition and gas release since it causes non-uniform moisture distributions in the soil matrix. It is not clear whether potential water repellency (PWR), measured on dried soils, can influence carbon dioxide (CO2) and methane (CH4) emissions under unsaturated moist conditions. This study aims to fill this knowledge gap using two water-repellent soils, and one non-repellent soil (NRS; control), under two temperature levels. Samples were collected from water-repellent Chamaecyparis obtusa (CYP) and Cryptomeria japonica (CED) forests, and the NRS was collected from Field Science Center in Ibaraki University, Ibaraki, Japan. Capillary-moistened samples were placed in closed chambers and separately exposed to 25 °C and 35 °C. Gas sampling was conducted in 1, 7, 14, 21, and 28 d. The PWR was measured with separate samples under the same conditions. CED soils showed significantly higher PWR compared with the NRS and CYP. The gas emission per g soil organic C (EGC; mg g-1 SOC h-1) was significantly low in CED soils compared with NRS and CYP, while NRS showed the highest emission. EGC of CO2 and CH4 showed significant strong negative correlations with PWR. The emission of CO2 and CH4 significantly increased with increasing temperature, and the Q10 was significantly high for CH4. Results indicated that the sensitivity to elevated PWR was higher for emission of CO2, whereas the sensitivity to the elevated temperature was higher for the emission of CH4. It was clear that PWR can influence moisture distribution in soil matrix in unsaturated moist soils and the processes that limit gaseous C emission. Further experiments are required on possible processes that enable PWR to influence gaseous C emission from moist soils.

Navigating Sustainability through Greenhouse Gas Emission Inventory: ESG Practices and Energy Shift in Bangladesh's Textile and Readymade Garment Industries.

As the world's demand for textiles and clothing rapidly increases, this industry's greenhouse gas (GHG) emissions are becoming a major environmental concern. Bangladesh, a key player in the global textile supply chain and one of the top producers, contributes significantly to these emissions. However, accessible data on activity and GHG emissions, crucial for researchers, the private sector, and policymakers in decision-making, is scarce. To address this gap, this study combines a detailed field survey with expert interviews to establish a comprehensive emission inventory. This inventory aims to identify hotspots and facilitate the adoption of effective mitigation strategies. Focusing on a prominent industrial zone's textile and readymade garments (RMG) industries, the research employs a mix of top-down and bottom-up approaches and follows the IPCC guidelines to develop a GHG emission inventory for 2022. The study evaluates various emission sources, including scope 1 (onsite fuel combustions), scope 2 (grid electricity usage), and scope 3 (waste and wastewater treatment). In the total emissions (6043.5 Gg CO2eq.), textile and RMG industries contribute 67.8% and 32.2%, respectively, with scope 1 emissions dominating at 85%. Notably, scope 2 emissions exhibit significant uncertainty (-10.4% to +11.9%), largely due to variations in national grid emission factors. This study forecasts GHG emissions until 2030, considering current trends (26 thousand Gg CO2 eq.). It also explores various energy mix scenarios, factoring in the depletion of existing natural gas reserves (ranging from 8 thousand to 33 thousand Gg CO2 eq.). This study delves into the impact of the Environmental, Social, and Governance (ESG) system on industries' GHG emissions. Besides improving worldwide emission databases and identifying hotspots, this research aims to promote a sustainable transition in both Bangladesh and other developing textile manufacturing nations across the globe.

Emerging trends of green hydrogen and sustainable environment in the case of Australia.

The world faces immense pressure regarding the negative impacts of increased greenhouse gas emissions, climate change, global warming, droughts, and many other environmental problems. Australia is also facing the same issues and requires urgent attention. In this research, we have examined the effect of hydrogen firms on Australia's greenhouse gas emissions. We employed the monthly data from January 2002 to December 2021 for econometric estimations. Through quantile regression, it is noted that the expansion of hydrogen firms contributes to environmental pollution instead of controlling the emissions. Most hydrogen energy still emits carbon dioxide, which contributes to climate change. Around the world, carbon-containing fossil fuels produce more than 95% of hydrogen energy. However, as a policy suggestion, it is recommended that green hydrogen produced by electrolysis of water using renewable energy sources will succeed in achieving the Sustainable Development Goals (SDGs).

Wetland productivity determines trade-off between biodiversity support and greenhouse gas production.

Establishing wetlands for nutrient capture and biodiversity support may introduce trade-offs between environmentally beneficial functions and detrimental greenhouse gas emissions. Investigating the interaction of nutrient capture, primary production, greenhouse gas production and biodiversity support is imperative to understanding the overall function of wetlands and determining possible beneficial synergistic effects and trade-offs. Here, we present temporally replicated data from 17 wetlands in hemi-boreal Sweden. We explored the relationship between nutrient load, primary producing algae, production of methane and nitrous oxide, and emergence rates of chironomids to determine what factors affected each and how they related to each other. Chironomid emergence rates correlated positively with methane production and negatively with nitrous oxide production, where water temperature was the main driving factor. Increasing nutrient loads reduced methanogenesis through elevated nitrogen concentrations, while simultaneously enhancing nitrous oxide production. Nutrient loads only indirectly increased chironomid emergence rates through increased chlorophyll-a concentration, via increased phosphorus concentrations, with certain taxa and food preference functional groups benefitting from increased chlorophyll-a concentrations. However, water temperature seemed to be the main driving factor for chironomid emergence rates, community composition and diversity, as well as for greenhouse gas production. These findings increase our understanding of the governing relationships between biodiversity support and greenhouse gas production, and should inform future management when constructing wetlands.

Reducing agricultural nitrous oxide emissions in China: the role of food production, forest cover, income, trade openness, and rural population.

In the light of China's carbon-neutral goal, this study examines how food production, forest cover, trade openness, and rural population contribute to the quest of addressing China's agricultural nitrous oxide emissions. Time series data ranging from 1971 to 2018 was used for analysis in this study. The autoregressive distributed lag (ARDL) technique was employed to evaluate potential cointegration as well as to ascertain the long and short-run effects of food production, forest cover, income, trade openness, and rural population on agricultural nitrous oxide emission. The Toda-Yamomoto causality analysis was also used to identify the causal relations between covariates (food production, forest cover, income, trade openness, and rural population) and the outcome variable (agricultural nitrous oxide emission). The long-run evidence is that rural population in itself tends to increase agricultural nitrous oxide emissions likewise food production. There is also validation of the existence of environmental Kuznets curve for agricultural nitrous oxide emissions. Moreover, income interacts with rural population to reduce agricultural nitrous oxide emissions in the long-run. Causality analysis indicated rural population affects the level of forest cover; forest cover is found to cause agricultural nitrous oxide emissions but the converse is not established, and income as well as the interaction between income and rural population determines agricultural nitrous oxide emissions. The short-run dynamics results establish an oscillatory equilibrium convergence for agricultural nitrous oxide emissions in event of structural disturbances. From the findings, the EKC hypothesis is relevant by offering avenue to reduce emission. Thus, income growth remains helpful in addressing nitrous oxide emission from the agricultural sector. However, research is needed to unravel why nitrous oxide tends to increase in many forest areas. Since food production cannot be halted, policy makers need to enhance the uptake of efficient food production technologies including developing and using more renewable energy for food production. It is important for authorities to attend to rural development in order to mitigate agricultural nitrous oxide emissions in China.

Greenhouse gas assemblages (CO2, CH4 and N2O) in the continental shelf of the Gulf of Cadiz (SW Iberian Peninsula).

This study examines the simultaneous water-atmosphere exchange of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) on the continental shelf of the Gulf of Cadiz, as well as the effect it has in terms of the radiative balance in the atmosphere, between 2014 and 2016. The experimental database consists of new measurements of the spatial and seasonal distribution of CO2 partial pressure (pCO2) and N2O concentration in 2016. pCO2 shows a wide range of variation influenced mainly by seasonal thermal variations (8.0 µatm 0C-1), as well as with the relative intensity of biological activity. There is experimental evidence of a progressive increase of pCO2 over the last 2 decades, with an estimated gradient of 4.2 ± 0.7 µatm y-1. During 2016, the Gulf of Cadiz acted as a slight source of CO2 to the atmosphere, with a mean flux of 0.4 ± 2.2 mmol m-2 d-1. The analysis of concentration variations in the water column shows that nitrification is the main N2O production process in the study area, although in the more coastal zone there are signs of inputs related to continental and sediment contributions, most probably induced by denitrification processes. In 2016, the Gulf of Cadiz acted as a weak sink of atmospheric N2O, with a mean flux of -0.1 ± 0.9 µmol m-2 d-1. From previous studies, performed with a similar methodology, an interannual database (2014-2016) of water-atmosphere fluxes of CO2, CH4 and N2O, normalized to the mean wind speed in the area, has been generated. Considering their respective Global Warming Potential (GWP) a joint greenhouse gasses (GHG) flux, expressed in CO2 equivalents of 0.6 ± 2.0 mmol m-2 d-1, has been estimated, which extended to the area of study indicates an approximate emission of 67.9 Gg CO2 y-1. However, although there is a high uncertainty associated with the spatial, temporal and interannual variations of CO2, CH4 and N2O fluxes in the Gulf of Cadiz, the exchange of greenhouse gasses could be influencing a radiative forcing increase in the atmosphere. When considering the available information on local and global estimates, the uncertainty about the effect of the joint exchange of GHGs to the atmosphere from the coastal seas increases significantly.

Agricultural ditches are hotspots of greenhouse gas emissions controlled by nutrient input.

Agricultural ditches are pervasive in agricultural areas and are potential greenhouse gas (GHG) hotspots, since they directly receive abundant nutrients from neighboring farmlands. However, few studies measure GHG concentrations or fluxes in this particular water course, likely resulting in underestimations of GHG emissions from agricultural regions. Here we conducted a one-year field study to investigate the GHG concentrations and fluxes from typical agricultural ditch systems, which included four different types of ditches in an irrigation district located in the North China Plain. The results showed that almost all the ditches were large GHG sources. The mean fluxes were 333 µmol m-2 h-1 for CH4, 7.1 mmol m-2 h-1 for CO2, and 2.4 µmol m-2 h-1 for N2O, which were approximately 12, 5, and 2 times higher, respectively, than that in the river connecting to the ditch systems. Nutrient input was the primary driver stimulating GHG production and emissions, resulting in GHG concentrations and fluxes increasing from the river to ditches adjacent to farmlands, which potentially received more nutrients. Nevertheless, the ditches directly connected to farmlands showed lower GHG concentrations and fluxes compared to the ditches adjacent to farmlands, possibly due to seasonal dryness and occasional drainage. All the ditches covered approximately 3.3% of the 312 km2 farmland area in the study district, and the total GHG emission from the ditches in this area was estimated to be 26.6 Gg CO2-eq yr-1, with 17.5 Gg CO2, 0.27 Gg CH4, and 0.006 Gg N2O emitted annually. Overall, this study demonstrated that agricultural ditches were hotspots of GHG emissions, and future GHG estimations should incorporate this ubiquitous but underrepresented water course.

White-rot fungi scavenge reactive oxygen species, which drives pH-dependent exo-enzymatic mechanisms and promotes CO2 efflux.

Soil organic matter (SOM) decomposition mechanisms in rainforest ecosystems are governed by biotic and abiotic procedures which depend on available oxygen in the soil. White-rot fungi (WRF) play an important role in the primary decomposition of SOM via enzymatic mechanisms (biotic mechanism), which are linked to abiotic oxidative reactions (e.g., Fenton reaction), where both processes are dependent on reactive oxygen species (ROS) and soil pH variation, which has yet been studied. In humid temperate forest soils, we hypothesize that soil pH is a determining factor that regulates the production and consumption of ROS during biotic and abiotic SOM decomposition. Three soils from different parent materials and WRF inoculum were considered for this study: granitic (Nahuelbuta, Schizophyllum commune), metamorphic (Alerce Costero, Stereum hirsutum), and volcanic-allophanic (Puyehue, Galerina patagonica). CO2 fluxes, lignin peroxidase, manganese peroxidase, and dye-decolorizing peroxidase levels were all determined. Likewise, the production of superoxide anion (O2•-), hydrogen peroxide (H2O2), and hydroxyl radicals (•OH) were assessed in soils microcosms after 36 days of anaerobic incubation with WRF inoculum and induced Fenton reaction under pH variations ranging from 2.5 to 5.1. ROS significantly increased biotic and abiotic CO2 emissions in all tested soils, according to the findings. The highest values (217.45 mg C kg-1) were found during the anaerobic incubation of sterilized and inoculated soils with WRF at a natural pH of 4.5. At pH 4.0, the lowest levels of C mineralization (82 mg C kg-1) were found in Nahuelbuta soil. Enzyme activities showed different trends as pH changed. The Fenton reaction consumed more H2O2 between pH 3 and 4, but less between pH 4.5 and 2.5. The mechanisms that oxidized SOM are extremely sensitive to variations in soil pH and the stability of oxidant radical and non-radical compounds, according to our findings.

The productive capacity and environment: evidence from OECD countries.

Environmental degradation is one of the most important and vital issues of today. In this context, many researchers are testing the environmental impact of different indicators. Many economic parameters affect environmental degradation. At the forefront of these parameters is the productive economic structures of the countries. For the first time in the literature, the present paper discusses the dynamic relationship between carbon dioxide (CO2) emissions, economic growth, and the productive capacity index (PCI) for a panel of 38 organization for economic co-operation and development (OECD) countries spanning the period 2000-2018. In this context, the PCI serves as a measure of the productive economic structure of a country. This empirical study applies panel cointegration techniques to reveal that the series are cointegrated in the long-run. In addition, the pooled mean group-panel autoregressive distributive lag (PMG-ARDL) approach is employed to estimate long-run coefficients. These coefficients confirm the environmental Kuznets curve hypothesis. Finally, the empirical findings confirm that improved productive capacity decreases environmental degradation. This results in important policy recommendations for involved governmental and private stakeholders.

Revisiting sampling duration to estimate N2O emission factors for manure application and cattle excreta deposition for the UK and Ireland.

According to the available guidelines, good practices for calculating nitrous oxide (N2O) emission factors (EFs) for livestock excreta and manure application include that sampling duration should be of at least one year after the nitrogen (N) application or deposition. However, the available experimental data suggest that in many cases most emissions are concentrated in the first months following N application. Therefore resources could be better deployed by measuring more intensively during a shorter period. This study aimed to assess the contribution of the N2O flux in the period directly after N application to the annual net emission. We used a database of 100 year-long plot experiments from different excreted-N sources (dung, urine, farmyard manure and slurry) used to derive EFs for the UK and Ireland. We explored different shorter potential measurement periods that could be used as proxies for cumulative annual emissions. The analysis showed that the majority of emissions occur in the first months after application, especially in experiments that i) had urine as the N source, ii) had spring N application, iii) were conducted on fine-textured soils, or iv) showed high annual emissions magnitude. Experiments that showed a smaller percentage of emissions in the first months also had a low magnitude of annual net emissions (below 370 gN2O-N ha-1 year-1), so the impact of measuring during a shorter period would not greatly influence the calculated EF. Accurate EF estimations were obtained by measuring for at least 60 days for urine (underestimation: 7.1%), 120 days for dung and slurry (4.7 and 5.1%) and 180 days for FYM (1.4%). At least in temperate climates, these results are promising in terms of being able to estimate annual N2O fluxes accurately by collecting data for less than 12 months, with significant resource-saving when conducting experiments towards developing country-specific EFs.

Rural electrification using renewable energy resources and its environmental impact assessment.

Integrating a group of generation units and loads into a microgrid improves power supply sustainability, decreases greenhouse gas emissions, and lowers generating costs. However, this integration necessitates the development of an improved energy management system. The microgrid distributes electricity among energy resources to optimize either the generating cost or the quantity of greenhouse gas emissions, or both at the same time. The low-cost energy supply requires a precise cost model for each energy component. This article aims to develop the generation cost model that incorporates renewable energy to lower the total operating cost and curb greenhouse gas emissions. The suggested optimization problem deals with the low-cost energy solution for the rural area of India. The proposed system used particle swarm optimization, a global optimization strategy, in the study. Minimum cost and emission scenarios are objective issues while operating with tolerable emissions, and costs are multi-objective of the present study. The outcomes of the scenarios are used to provide viable optimized solutions to multi-objective problems using the optimization technique. Finally, a battery bank's potential to compensate for generation shortages while minimizing emissions is being studied. The study is performed on a microgrid comprising photovoltaic PV, diesel generator, battery, wind turbine, and an Indian rural scenario load profile. The finding suggested that the optimal configuration has a total net cost of operation is $59,195.61. The per-unit cost of energy is 0.20 $/kWh with a saving of [Formula: see text] emission is 5994 kg/year. This modular feasibility analysis demonstrates that utilizing a hybrid energy system to power the planning is cost-effective. This research is anticipated to aid rural communities and other stakeholders in making well-informed decisions throughout the planning stages of similar initiatives.

Global electric vehicle adoption: implementation and policy implications for India.

Present transport system of conventional vehicle in India has faced challenges due to enormous amount of air pollution, health hazards to human, rising oil price, insufficient indigenous fossil fuel reserve, heavy expenditure on oil import, energy insecurity, etc. Electrical vehicle (EV) is considered to be alternatives of conventional vehicles that can overcome these shortcomings. The aim of the study is to get an overview of the electric vehicle policies of government of India and its state governments to find out their relevance and impact on EV adoption in India. Exploratory research is used in present case to carry out the study. Currently, the EV industry in India is in preliminary condition and in growing stage. Government of India has framed policies such as "NEMMP 2020," "FAME-I," "FAME-II," and Vehicle Scrappage policy. Seventeen of its state governments have framed EV policy. These policies facilitated various types of incentives, infrastructure development, fund allocation, research and development, production, and sales. This will have strong impact on EV demand generation, conversion of conventional vehicles to e-vehicle resulting E-mobility transformation and EV hub in the region that is at par with other EV-developed countries in the world. However, lack of policy and technology availability in the domain of disposal and reprocessing of Li-ion battery is found to be a future limitation of EV prospect in Indian context which needs to be looked into.

Evading the Entrepreneurship: A Study to Discover Implementable Online Approaches to Avoid Greenhouse Consequences.

Greenhouse gases emissions due to climate change are a continuous threat to the global world, mainly relying on the pervasive consumption of numerous products, including synthetic and non-synthetic products. This research focused on the green purchase intentions of students in Pakistan towards different products, which are related to minimising the greenhouse effect and are available for sale on numerous e-commerce websites, ultimately proceeding to green entrepreneurship. The main objective of this study was to determine which methodology was better among product listing, social media advertising, and online virtual community to enhance customer online green purchase intention while considering online information about the greenhouse effect as a mediating variable. The AMOS 24 was used for this research. SEM was performed with the help of bootstrap methodology. The research was conducted on 280 students at different educational institutes in Pakistan, using a simple random sampling technique. A finding of this study suggested that all three methods positively impacted the green purchase intention of consumers and green entrepreneurship, but online virtual communities could be considered in a more effective way to enhance the green purchase intention of its targeted customers.

Quantifying groundwater carbon dioxide and methane fluxes to an urban freshwater lake using radon measurements.

Freshwater lakes can play a significant role in greenhouse gas budgets as they can be sources or sinks of carbon to the atmosphere. However, there is limited information on groundwater discharge being a source of carbon to freshwater lakes. Here, we measure CO2 and CH4 in the largest urban freshwater lake in the metropolitan area of Sydney (Australia) and quantify groundwater discharge rates into the lake using radon (222Rn, a natural groundwater tracer). We also assess the spatial variability of radon, CO2 and CH4 in the lake, in addition to surface water and groundwater nutrient and carbon concentrations. Results revealed that the lake system was a source of CO2 and CH4 to the atmosphere with fluxes of 113 ± 81 and 0.3 ± 0.1 mmol/m2/d, respectively. These calculated CO2 fluxes were larger than commonly observed lake fluxes and the global average flux from lakes. However, CH4 fluxes were lower than the average global value. Based on the radon mass balance model, groundwater discharge to the lake was 16 ± 10 cm/d, which resulted in groundwater-derived CO2 and CH4 fluxes contributing 25 and 13% to the overall greenhouse gas emissions from the lake, respectively. Radon, CO2 and CH4 maps showed similar spatial distribution trends in the lake and a strong relationship between radon, NO3 and NH4 suggested groundwater flow was also a driver of nitrogen into the lake from the western side of the lake, following the general regional groundwater flow. This work provides insights into groundwater and greenhouse gas dynamics in Sydney's largest urban freshwater lake with two implications for carbon budgets: to incorporate urban lakes in global carbon budgets and to account for, the often ignored, groundwater discharge as a source of carbon to lakes.

Divergent effects of hydrological alteration and nutrient addition on greenhouse gas emissions in the water level fluctuation zone of the Three Gorges Reservoir, China.

Changes in global rainfall patterns and construction of artificial dams have led to widespread alteration of hydrological processes in riparian ecosystems. At the same time, many riparian ecosystems, such as those associated with the Yangtze, are being subjected to enhanced inputs of nitrogen (N) and phosphorus (P) due to intensified agricultural activity in surrounding uplands. Together, these environmental changes may alter the magnitude and direction of greenhouse gasses (GHGs) fluxes from riparian soils. We conducted an in situ experiment combined with quantitative PCR approach (qPCR) to elucidate the effects of hydrological alterations (continuous flooding (CF), periodic flooding (PF), and no flooding (NF)) and nutrient addition (N addition (urea, 100 kg N ha-1 y-1), P addition (P2O5, 20 kg ha-1y-1), N + P addition, and control (CK)) on three major GHGs including carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes as well as the underlying mechanisms. Our results showed that hydrological alterations greatly affected GHGs emissions, possibly by altering soil moisture, soil organic C, and C:N ratios. The CF, with higher soil moisture and lower C:N ratio, increased CH4 emissions 13-fold and reduced CO2 and N2O emissions by 37.3% and 72.2% averaged over the growing seasons compared with no flooding. PF enhanced CH4 emissions 5.7-fold and decreased N2O emissions by 69.0% in comparison with no flooding. Nutrient additions had no significant effect on CO2 or CH4 flux, but P addition significantly lowered N2O flux. Interactions between hydrological alterations and nutrient additions were not detected for any GHGs. As a result, hydrological alterations and nutrient additions affected the global warming potential (GWP) of growing season GHG budgets on a 100-year time horizon, mainly by changing the CO2 emissions. CF reduced GWP from 597 to 439 g CO2-eq m-2, and N + P addition enhanced GWP from 489 to 625 g CO2-eq m-2. The qPCR analysis revealed that decreased CH4 oxidation potential may lead to the enrichment of CH4 emissions under the hydrological alterations, and reduced nitrification and denitrification potential contributed to the reduction of N2O fluxes under all the treatments. Our study indicates that continuous flooding could curb the contribution of riparian GHGs fluxes to global warming but that the combination of N and P additions may increase the greenhouse effect mainly by regulating the CO2 emissions of growing season in riparian ecosystem.

Targeted and Untargeted Metabolic Profiling to Discover Bioactive Compounds in Seaweeds and Hemp Using Gas and Liquid Chromatography-Mass Spectrometry.

Greenhouse gas emissions are a global problem facing the dairy/beef industry. Novel feed additives consisting of seaweeds and hemp containing bioactive compounds are theorized to reduce enteric methane emissions. In this study we aimed to investigate the metabolic profiles of brown, red and green seaweeds and hemp using gas chromatography and liquid chromatography mass spectrometry. We used targeted and untargeted approaches, quantifying known halomethanes and phenolics, as well as identifying potentially novel bioactive compounds with anti-methanogenic properties. The main findings were: (a) Asparagopsis taxiformis contained halomethanes, with high concentrations of bromoform (4200 µg/g DW), six volatile halocarbons were tentatively identified; (b) no halomethanes were detected in the other studied seaweeds nor in hemp; (c) high concentrations of lignans were measured in hemp; (d) a high numbers of sulfated phenolic acids and unidentified sulfuric acid-containing compounds were detected in all seaweeds; (e) flavonoid glucosides and glucuronides were mainly identified in hemp; and (f) the condensed tannin gallocatechin was tentatively identified in Fucus sp. Using the combined metabolomics approach, an overview and in-depth information on secondary metabolites were provided. Halomethanes of Asparagopsis sp. have already been shown to be anti-methanogenic; however, metabolic profiles of seaweeds such as Dictyota and Sargassum have also been shown to contain compounds that may have anti-methanogenic potential.

Assessing the impact of transition from nonrenewable to renewable energy consumption on economic growth-environmental nexus from developing Asian economies.

Greenhouse gasses have adverse effects on global warming and air pollution and need to be optimized by minimizing the contributing factors. This work analyzes the effects of economic growth and energy resources (renewable and nonrenewable) on the emissions of greenhouse gasses (GHG). A 2000-2016 panel data from 25 developing Asian countries is analyzed through a robust Random Effect (RE) approach and Hausman Taylor Regression (HTR). Findings show a positive correlation between economic growth and energy consumption, while a 1% increase in renewable energy consumption results in a 0.193% decrease in carbon emissions. Economic growth and renewable energy are positively correlated in both the short and long term, which implies a valid feedback hypothesis. The findings indicate the significant contribution of nonrenewable energy resources to greenhouse gas emissions and the positive impact of renewable resources on greenhouse gas emissions' control. Furthermore, this study highlights the potential of developing Asian economies to preserve the environment through more robust regional environmental policies and renewable energy resources. In light of this study's findings, policymakers in Asian developing economies should develop policies on Renewable Energy infrastructure (RE) to improve GDP and reduce greenhouse gas emissions.

The non-negligibility of greenhouse gas emission from a combined pre-composting and vermicomposting system with maize stover and cow dung.

The acceptance of combined pre-composting and vermicomposting systems is increasing because of the advantage in rapidly stabilizing organic wastes and reducing emission of greenhouse gasses (GHG). However, GHG emission during the pre-composting phase is often neglected when evaluating the system. This study aimed to quantify GHG emission from a combined pre-composting and vermicomposting system and to investigate the effects of earthworms on GHG emission. A combined system using Eisenia fetida was employed to stabilize maize stover and cow dung (mixing ratio 60:40). The inoculating densities were 60 (T1), 120 (T2), and 180 (T3) earthworms per kilogram of substrate. A traditional composting system without earthworms was set as a control (T0). The results indicated that earthworms increased CO2 while decreased CH4 and N2O emissions compared to the control. Higher emission of CO2 suggested that the earthworms promoted the degradation of the substrates. Lower emission of CH4 and N2O showed the advantage of the combined system because CH4 and N2O possess extremely higher global warming potential than that of CO2. T2 is recommended for stabilizing maize stover and cow dung when making a tradeoff between stabilization rate and reduction of GHG. The percentages of GHG emission during pre-composting relative to total GHG emission in T1, T2, and T3 were 34%, 35%, and 30%, respectively. GHG emission is non-negligible when using a combined system, especially the emission of GHG during the pre-composting phase cannot be ignored.

Divergent consequences of different biochar amendments on carbon dioxide (CO2) and nitrous oxide (N2O) emissions from the red soil.

Climate change due to greenhouse gas (GHG) emissions is one of the global environmental matters of the 21st century. Biochar (BC) amendments have been proposed as a potential solution for improving soil quality and to mitigate GHGs emissions. Therefore, we evaluated the influence of different BCs on soil CO2 and N2O emissions in an outdoor pot experiment. The soil was mixed with three different types of BCs; bamboo, hardwood, and rice straw BCs as BB, BH, and BR, respectively, and control as B0 with four levels (0, 5, 20, and 80 g kg-1 of soil). Gas samples were collected on a bi-monthly basis for six months. A polyvinyl chloride (PVC) static chamber was placed on each replicate to collect the gas samples at 15, 30, 45, and 60 min, respectively. Compared to B0, the lowest cumulative N2O emissions were observed in BH80 (11%) followed by BH20, BH5, and BR80. However, for cumulative CO2 emissions, B0 and BC treatments showed no significant differences except for BB80 (>11%) and BB5 (<2%). BC type and level both had a significant (P < 0.001) impact on the cumulative N2O emissions with a significant interaction (P < 0.001). However, cumulative CO2 emissions were unaffected by BC type but BC level showed a significant influence on cumulative CO2 emissions (P < 0.05) and there was a significant (P < 0.001) interaction between the BC type and level on cumulative CO2 emissions. Overall, higher doses of BR and BB showed a pronounced effect on soil pH over BH. The soil pH and moisture showed a negative correlation with N2O emissions whereas soil temperature showed a positive correlation with the cumulative fluxes of N2O. Our results demonstrate that BC incorporation to soil may help to mitigate GHGs emissions but its influence may vary with BC type and level under different conditions and soil type.