Biogeochemical transformation of greenhouse gas emissions from terrestrial to atmospheric environment and potential feedback to climate forcing

Increasing soil nitrous acid emissions driven by climate and fertilization change aggravate global ozone pollution

Soil microbial nitrous acid (HONO) production is an important source of atmospheric reactive nitrogen that affects air quality and climate. However, long-term global soil HONO emissions driven by climate change and fertilizer use have not been quantified. Here, we derive the global soil HONO emissions over the past four decades and evaluate their impacts on ozone (O3) and vegetation. Results show that climate change and the increased fertilizer use enhanced soil HONO emissions from 9.4 Tg N in 1980 to 11.5 Tg N in 2016. Chemistry-climate model simulations show that soil HONO emissions increased global surface O3 mixing ratios by 2.5% (up to 29%) and vegetation risk to O3, with increasing impact during 1980s-2016 in low-anthropogenic-emission regions. With future decreasing anthropogenic emissions, the soil HONO impact on air quality and vegetation is expected to increase. We thus recommend consideration of soil HONO emissions in strategies for mitigating global air pollution.

Effects of different sizes of microplastic particles on soil respiration, enzyme activities, microbial communities, and seed germination

Microplastics (MPs) are emerging pollutants of terrestrial ecosystems. The impacts of MP particle size on terrestrial systems remain unclear. The current study aimed to investigate the effects of six particle sizes (i.e., 4500, 1500, 500, 50, 5, and 0.5 μm) of polyethylene (PE) and polyvinyl chloride (PVC) on soil respiration, enzyme activity, bacteria, fungi, protists, and seed germination. MPs significantly promoted soil respiration, and the stimulating effects of PE were the strongest for medium and small-sized (0.5-1500 μm) particles, while those of PVC were the strongest for small particle sizes (0.5-50 μm). Large-sized (4500 μm) PE and all sizes of PVC significantly improved soil urease activity, while medium-sized (1500 μm) PVC significantly improved soil invertase activity. MPs altered the soil microbial community diversity, and the effects were especially pronounced for medium and small-sized (0.5-1500 μm) particles of PE and PVC on bacteria and fungi and small-sized (0.5 μm) particles of PE on protists. The impacts of MPs on bacteria and fungi were greater than on protists. The seed germination rate of Brassica chinensis decreased gradually with the decrease in PE MPs particle size. Therefore, to reduce the impact of MPs on soil ecosystems, effective measures should be taken to avoid the transformation of MPs into smaller particles in soil environmental management.

Linking carbon storage with land use dynamics in a coastal Ramsar wetland

Coastal wetland ecosystems make an important contribution to the global carbon pool, yet their extent is declining due to aquaculture-related land use changes. We conducted an extensive investigation into the carbon stock and area coverage of macrophytes in a tropical coastal Ramsar wetland, Kolleru in Andhra Pradesh, India. A total of 72 quadrats of size 1 × 1 m2 were laid in the wetland, 19 species of macrophytes were collected and analyzed for carbon content using a CNHS analyzer. To assess changes in the wetland macrophytes, Normalized Difference Vegetation Index (NDVI) was estimated using Landsat time series data from 1975 to 2023. The importance value index (IVI) of macrophytes scored highest for the Ipomoea aquatica (41.4) and the lowest for Ottelia alismoides (1.9). Non-metric multidimensional scaling (NMDS) significantly (r = 0.1905, p = 0.0361) revealed a clear separation of macrophytes in ordination space. ANOVA indicated highly significant (p < 0.0001) variations in the carbon content of aboveground and belowground components of macrophytes. Among the different macrophytes, the highest carbon content was found in Phragmites karka (0.6 g. g-1) and the lowest was recorded in Utricularia stellaris (0.2 g. g-1). On an average, emergents in the Kolleru wetland sequester 1525 ± 181 g C m-2 yr-1, rooted floating species sequester 858 ± 101 g C m-2 yr-1, submerged macrophytes sequester 480 ± 60 g C m-2 yr-1, and free-floating macrophytes sequester 221 ± 90 g C m-2 yr-1. Land cover mapping revealed a decrease in spread of aquatic vegetation from 225.2 km2 in 1975 to 100.6 km2 in 2023. Although macrophytes are vital carbon sinks, the wetland conversion into fishponds has resulted in a loss of 55.3 % of carbon storage. Therefore, immediate restoration of macrophyte cover is vital for the proper functioning of carbon sequestration and mitigation of climate change impacts.

Intermodal travel planning and decision support integrated with transportation and energy systems

The fast urbanization in China makes it all the more important to find sustainable solutions that are both comprehensive and energy-efficient. Because of its important role in lowering logistical expenses and pollutant emissions, intermodal transport is generally seen as an effective method of coordinating transportation operations, helping to address the growing economic and environmental issues. Considering the characteristics of a growing city, this article lays out a multi-criteria method for selecting which new initiatives for China's public transportation system should be prioritized. "Electric municipality bus," "light rail system," and "modernization to the current fleet and optimization" are the three enhancement initiatives that are outlined. Using transportation-related economic, social, and environmental sub-criteria, this research applies TOPSIS, an analytic hierarchy method and fuzzy approach for order preference by resemblance to ideal circumstance application, to prioritize transportation projects. The study aims to improve city life in Chongqing, China, by identifying the most environmentally friendly development projects. Applying the analytical hierarchy method (AHP), the relative importance of several sustainability criteria was established for use in making strategic decisions. The alternative projects for the given city have been ranked using the fuzzy TOPSIS approach. However, the investigated results show the supportive response of hybrid to environmental sustainability and vice versa for non-hybrid vehicles. However, the energy consumption in public transport remains a leading hurdle in sustainability across the three modes of transport: taxis, rail transit and buses. Finally, computer trains in public transport also surprisingly deal with environmental sustainability to keep the current & forthcoming generation from ecological harm. However, theoretical and empirical policy suggestions have been proposed to become clean & green shortly.

Changes in nutrient availability substantially alter bacteria and extracellular enzymatic activities in Antarctic soils

In polar regions, global warming has accelerated the melting of glacial and buried ice, resulting in meltwater run-off and the mobilization of surface nutrients. Yet, the short-term effects of altered nutrient regimes on the diversity and function of soil microbiota in polyextreme environments such as Antarctica, remains poorly understood. We studied these effects by constructing soil microcosms simulating augmented carbon, nitrogen, and moisture. Addition of nitrogen significantly decreased the diversity of Antarctic soil microbial assemblages, compared with other treatments. Other treatments led to a shift in the relative abundances of these microbial assemblages although the distributional patterns were random. Only nitrogen treatment appeared to lead to distinct community structural patterns, with increases in abundance of Proteobacteria (Gammaproteobateria) and a decrease in Verrucomicrobiota (Chlamydiae and Verrucomicrobiae).The effects of extracellular enzyme activities and soil parameters on changes in microbial taxa were also significant following nitrogen addition. Structural equation modeling revealed that nutrient source and extracellular enzyme activities were positive predictors of microbial diversity. Our study highlights the effect of nitrogen addition on Antarctic soil microorganisms, supporting evidence of microbial resilience to nutrient increases. In contrast with studies suggesting that these communities may be resistant to change, Antarctic soil microbiota responded rapidly to augmented nutrient regimes.

Effects of straw returning combined with blended controlled-release urea fertilizer on crop yields, greenhouse gas emissions, and net ecosystem economic benefits: A nine-year field trial

Although straw returning combined with blended controlled-release urea fertilizer (BUFS) has been shown to improve wheat-maize rotation system productivity, their effects on greenhouse gas (GHG) emissions, carbon footprints (CF), and net ecosystem economic benefits (NEEB) are still unknown. Life cycle assessment was used to investigate a long-term (2013-2022) wheat-maize rotation experiment that included straw combined with two N fertilizer types [BUFS and (conventional urea fertilizer) CUFS] and straw-free treatments (BUF and CUF). The results showed that BUFS and CUFS treatments increased the annual yield by 13.8% and 11.5%, respectively, compared to BUF and CUF treatments. The BUFS treatment increased the yearly yield by 13.8% compared to the CUFS treatment. Since BUFS and CUFS treatments increased soil organic carbon (SOC) sink sequestration by 25.0% and 27.0% compared to BUF and CUF treatments, they reduced annual GHG emissions by 7.1% and 4.7% and CF per unit of yield (CFY) by 13.7% and 9.6%, respectively. BUFS treatment also increased SOC sink sequestration by 20.3%, reduced GHG emissions by 10.7% and CFY by 23.0% compared to CUFS treatment. It is worth noting that the BUFS and CUFS treatments increased the annual ecological costs by 41.6%, 26.9%, and health costs by 70.1% and 46.7% compared to the BUF and CUF treatments, but also increased the net yield benefits by 9.8%, 6.8%, and the soil nutrient cycling values by 29.2%, 27.3%, and finally improved the NEEB by 10.1%, 7.3%, respectively. Similar results were obtained for the BUFS treatment compared to the CUFS treatment, ultimately improving the NEEB by 23.1%. Based on assessing yield, GHG emissions, CF, and NEEB indicators, the BUFS treatment is recommended as an ideal agricultural fertilization model to promote sustainable and clean production in the wheat-maize rotation system and to protect the agroecological environment.

Selenium-Induced Enhancement in Growth and Rhizosphere Soil Methane Oxidation of Prickly Pear

As an essential element for plants, animals, and humans, selenium (Se) has been shown to participate in microbial methane oxidation. We studied the growth response and rhizosphere methane oxidation of an economic crop (prickly pear, Rosa roxburghii Tratt) through three treatments (Se0.6 mg/kg, Se2.0 mg/kg, and Se10 mg/kg) and a control (Se0 mg/kg) in a two-month pot experiment. The results showed that the height, total biomass, root biomass, and leaf biomass of prickly pear were significantly increased in the Se0.6 and Se2.0 treatments. The root-to-shoot ratio of prickly pear reached a maximum value in the Se2 treatment. The leaf carotenoid contents significantly increased in the three treatments. Antioxidant activities significantly increased in the Se0.6 and Se2 treatments. Low Se contents (0.6, 2 mg/kg) promoted root growth, including dry weight, length, surface area, volume, and root activity. There was a significant linear relationship between root and aboveground Se contents. The Se translocation factor increased as the soil Se content increased, ranging from 0.173 to 0.288. The application of Se can improve the state of rhizosphere soil's organic C and soil nutrients (N, P, and K). Se significantly promoted the methane oxidation rate in rhizosphere soils, and the Se10 treatment showed the highest methane oxidation rate. The soil Se gradients led to differentiation in the growth, rhizosphere soil properties, and methane oxidation capacity of prickly pear. The root Se content and Se translocation factor were significantly positively correlated with the methane oxidation rate. Prickly pear can accumulate Se when grown in Se-enriched soil. The 2 mg/kg Se soil treatment enhanced growth and methane oxidation in the rhizosphere soil of prickly pear.

Carbon trade-off and energy budgeting under conventional and conservation tillage in a rice-wheat double cropping system

Amid rising energy crises and greenhouse gas (GHG) emissions, designing energy efficient, GHG mitigation and profitable conservation farming strategies are pertinent for global food security. Therefore, we tested a hypothesis that no-till with residue retaining could improve energy productivity (EP) and energy use efficiency (EUE) while mitigating the carbon footprint (CF), water footprint (WF) and GHG emissions in rice-wheat double cropping system. We studied two tillage viz., conventional and conservation, with/without residue retaining, resulting as CT0 (puddled-transplanted rice, conventional wheat -residue), CTR (puddled-transplanted rice, conventional wheat + residue), NT0 (direct seeded rice, zero-till wheat -residue), and NTR (direct seeded rice, zero-till wheat + residue). The overall results showed that the NTR/NT0 had 34% less energy consumption and 1.2-time higher EP as compared to CTR/CT0. In addition, NTR increased 19.8% EUE than that of CT0. The grain yield ranged from 8.7 to 9.3 and 7.8-8.5 Mg ha-1 under CT and NT system, respectively. In NTR, CF and WF were 56.6% and 17.9% lower than that of CT0, respectively. The net GHG emissions were the highest (7261.4 kg CO2 ha-1 yr-1) under CT0 and lowest (4580.9 kg CO2 ha-1 yr-1) under NTR. Notably, the carbon sequestration under NTR could mitigate half of the system's CO2-eq emissions. The study results suggest that NTR could be a viable option to offset carbon emissions and water footprint by promoting soil organic carbon sequestration, and enhancing energy productivity and energy use efficiency in the South Asian Indo-Gangetic Plains.

Transcriptional regulation of soluble methane monooxygenase via enhancer-binding protein derived from Methylosinus sporium 5

Methane is a major greenhouse gas, and methanotrophs regulate the methane level in the carbon cycle. Soluble methane monooxygenase (sMMO) is expressed in various methanotroph genera, including Alphaproteobacteria and Gammaproteobacteria, and catalyzes the hydroxylation of methane to methanol. It has been proposed that MmoR regulates the expression of sMMO as an enhancer-binding protein under copper-limited conditions; however, details on this transcriptional regulation remain limited. Herein, we elucidate the transcriptional pathway of sMMO depending on copper ion concentration, which affects the interaction of MmoR and sigma factor. MmoR and sigma-54 (σ54) from Methylosinus sporium 5 were successfully overexpressed in Escherichia coli and purified to investigate sMMO transcription in methanotrophs. The results indicated that σ54 binds to a promoter positioned -24 (GG) and -12 (TGC) upstream between mmoG and mmoX1. The binding affinity and selectivity are lower (Kd = 184.6 ± 6.2 nM) than those of MmoR. MmoR interacts with the upstream activator sequence (UAS) with a strong binding affinity (Kd = 12.5 ± 0.5 nM). Mutational studies demonstrated that MmoR has high selectivity to its binding partner (ACA-xx-TGT). Titration assays have demonstrated that MmoR does not coordinate with copper ions directly; however, its binding affinity to UAS decreases in a low-copper-containing medium. MmoR strongly interacts with adenosine triphosphate (Kd = 62.8 ± 0.5 nM) to generate RNA polymerase complex. This study demonstrated that the binding events of both MmoR and σ54 that regulate transcription in M. sporium 5 depend on the copper ion concentration. IMPORTANCE This study provides biochemical evidence of transcriptional regulation of soluble methane monooxygenase (sMMO) in methanotrophs that control methane levels in ecological systems. Previous studies have proposed transcriptional regulation of MMOs, including sMMO and pMMO, while we provide further evidence to elucidate its mechanism using a purified enhancer-binding protein (MmoR) and transcription factor (σ54). The characterization studies of σ54 and MmoR identified the promoter binding sites and enhancer-binding sequences essential for sMMO expression. Our findings also demonstrate that MmoR functions as a trigger for sMMO expression due to the high specificity and selectivity for enhancer-binding sequences. The UV-visible spectrum of purified MmoR suggested an iron coordination like other GAF domain, and that ATP is essential for the initiation of enhancer elements. Binding assays indicated that these interactions are blocked by the copper ion. These results provide novel insights into gene regulation of methanotrophs.

Nanoremediation strategies to address environmental problems

A rapid rise in population, extensive anthropogenic activities including agricultural practices, up-scaled industrialization, massive deforestation, etc. are the leading causes of environmental degradation. Such uncontrolled and unabated practices have affected the quality of environment (water, soil, and air) synergistically by accumulating huge quantities of organic and inorganic pollutants in it. Environmental contamination is posing a threat to the existing life on the Earth, therefore, demands the development of sustainable environmental remediation approaches. The conventional physiochemical remediation approaches are laborious, expensive, and time-consuming. In this regard, nanoremediation has emerged as an innovative, rapid, economical, sustainable, and reliable approach to remediate various environmental pollutants and minimize or attenuate the risks associated with them. Owing to their unique properties such as high surface area to volume ratio, enhanced reactivity, tunable physical parameters, versatility, etc. nanoscale objects have gained attention in environmental clean-up practices. The current review highlights the role of nanoscale objects in the remediation of environmental contaminants to minimize their impact on human, plant, and animal health; and air, water, and soil quality. The aim of the review is to provide information about the applications of nanoscale objects in dye degradation, wastewater management, heavy metal and crude oil remediation, and mitigation of gaseous pollutants including greenhouse gases.

Assessing the Relationship between Annual Surface Temperature Changes and the Burden of Dengue: Implications for Climate Change and Global Health Outcomes

Dengue fever remains a significant global health concern, imposing a substantial burden on public health systems worldwide. Recent studies have suggested that climate change, specifically the increase in surface temperatures associated with global warming, may impact the transmission dynamics of dengue. This study aimed to assess the relationship between annual surface temperature changes from 1961 to 2019 and the burden of dengue in 185 countries. The dengue burden was evaluated for 2019 using disability-adjusted life years (DALYs) and the annual rate of change (ARC) in DALY rates assessed from 1990 to 2019. A cross-sectional and ecological analysis was conducted using two publicly available datasets. Regression coefficients (β) and 95% confidence intervals (CI) were used to examine the relationship between annual surface temperature changes and the burden of dengue. The results revealed a significant negative relationship between mean surface temperatures and DALY rates in 2019 (β = -16.9, 95% CI -26.9 to -6.8). Similarly, a significant negative relationship was observed between the temperature variable and the ARC (β = -0.99, 95% CI -1.66 to -0.32). These findings suggest that as temperatures continue to rise, the burden of dengue may globally decrease. The ecology of the vector and variations in seasons, precipitation patterns, and humidity levels may partially contribute to this phenomenon. Our study contributes to the expanding body of evidence regarding the potential implications of climate change for dengue dynamics. It emphasizes the critical importance of addressing climate change as a determinant of global health outcomes.

Investigating global surface temperature from the perspectives of environmental, demographic, and economic indicators: current status and future temperature trend

Anthropogenic activities have increased atmospheric concentrations of greenhouse gas emissions, which have observably increased global temperature. Recognizing it as one of the most critical issues caused by human activities, this study investigates the effects of environmental, demographic, and economic indicators on global and regional temperature. For this purpose, advanced and powerful machine learning techniques, such as ANN, CNN, SVM, and LSTM, are employed using the data from 1980 to 2018 of the aforementioned regions to predict and forecast global and regional temperatures in Africa, Asia, Europe, North America, and South America. First, the predicted results were found very close to the actual surface temperature, confirming that environmental, economic, and demographic indicators are critical drivers of climate change. Second, this study forecasted global temperature from 2023 to 2050 and regional temperature from 2022 to 2050. The results also predicted a considerable increase in global temperature and regional temperature in the forthcoming years. Particularly, Asia and Africa may experience extreme weather in the future with an increase of more than 1.6 °C. Based on the findings of this study, the major implications have been that maintaining greenhouse gas emissions, balancing economic development, urbanization, and environmental quality while reducing fossil fuel energy consumption will ensure climate mitigation. The findings demand an alteration in human behavior regarding fossil fuel energy consumption to control greenhouse gas emissions, which is the most significant contributor to climate change.

Predicting soil erosion potential under CMIP6 climate change scenarios in the Chini Lake Basin, Malaysia

Climate change and soil erosion are very associated with environmental defiance which affects the life sustainability of humans. However, the potency effects of both events in tropical regions are arduous to be estimated due to atmospheric conditions and unsustainable land use management. Therefore, several models can be used to predict the impacts of distinct climate scenarios on human and environmental relationships. In this study, we aimed to predict current and future soil erosion potential in the Chini Lake Basin, Malaysia under different Climate Model Intercomparison Project-6 (CMIP6) scenarios (e.g., SSP2.6, SSP4.5, and SSP8.5). Our results found the predicted mean soil erosion values for the baseline scenario (2019-2021) was around 50.42 t/ha year. The mining areas recorded the highest soil erosion values located in the southeastern part. The high future soil erosion values (36.15 t/ha year) were obtained for SSP4.5 during 2060-2080. Whilst, the lowest values (33.30 t/ha year) were obtained for SSP2.6 during 2040-2060. According to CMIP6, the future soil erosion potential in the study area would reduce by approximately 33.9% compared to the baseline year (2019-2021). The rainfall erosivity factor majorly affected soil erosion potential in the study area. The output of the study will contribute to achieving the United Nations' 2030 Agenda for Sustainable Development.

Physically separated soil organic matter pools as indicators of carbon and nitrogen change under long-term fertilization in a Chinese Mollisol

Isolation and quantification of soil organic matter (SOM) pools under the influence of management practices is needed for assessing the changes in soil fertility. However, the knowledge on how the active, slow and passive pools of SOM respond to long-term fertilization is scarce. Therefore, the present study was designed to isolate the active, slow, and passive pools of soil organic matter through physical fractionation under long-term fertilization. The treatments included; inorganic fertilization (NPK) either alone or combined with a normal dose of manure (MNPK) or a high dose of manure (1.5MNPK) with an unfertilized control (CK) for comparison. The isolated pools were analyzed and compared for their sizes, SOC and TN storage and their contribution to total SOC and TN sequestration. The results revealed that the fertilization enhanced the active, slow and passive pools of SOC and TN and their storage under applied treatments was patterned as 1.5MNK > MNPK > NPK > CK. The highest SOC and TN storage was observed in the active pool, while, greater response to fertilization (in terms of response ratio) was associated with the slow pool. Results show that fertilization enhanced the proportion of SOC and TN stocks to bulk SOC and TN stocks in active and slow pools, while a diminishing trend was found for passive pools. Moreover, the highest response ratio was found for TN sequestration in each pool as compared to SOC, suggesting preferential accumulation of TN over SOC in the studied soil. Nevertheless, the highest SOC and TN storage took place in the active pool. The slow pool showed greater response to applied fertilizer, with the highest values being observed under 1.5MNPK. This study concluded that long-term manure + inorganic fertilization is crucial for enhancing C and N sequestration by altering the size and response of SOM pools.

Assessment of digestates prepared from maize, legumes, and their mixed culture as soil amendments: Effects on plant biomass and soil properties

Digestate prepared from anaerobic digestion can be used as a fertilizer, as it contains ample amounts of plant nutrients, mainly nitrogen, phosphorous, and potassium. In this regard, digestates produced from mixed intercropped cereal and legume biomass have the potential to enrich soil and plants with nutrients more efficiently than monoculture-based digestates. The objective of this study was to determine the impact of different types of digestates applied at a rate of 40 t·ha-1 of fresh matter on soil properties and crop yield in a pot experiment with lettuce (Lactuca sativa) as a test crop. Anaerobic digestion of silages was prepared from the following monocultures and mixed cultures: broad bean, maize, maize and broad bean, maize and white sweet clover, and white sweet clover. Anaerobic digestion was performed in an automatic custom-made system and applied to the soil. Results revealed that fresh and dry aboveground biomass as well as the amount of nitrogen in plants significantly increased in all digestate-amended variants in comparison to control. The highest content of soil total nitrogen (+11% compared to the control) and urease (+3% compared to control) were observed for maize digestate amendment. Broad bean digestate mediated the highest oxidizable carbon (+48%), basal respiration (+46%), and N-acetyl-β-D-glucosamine-, L-alanine-, and L-lysine-induced respiration (+22%, +35%, +22%) compared to control. Moreover, maize and broad bean digestate resulted in the highest values of N-acetyl-β-D-glucosaminidase and β -glucosidase (+35% and +39%), and maize and white sweet clover digestate revealed the highest value of arylsulfatase (+32%). The observed differences in results suggest different effects of applied digestates. We thus concluded that legume-containing digestates possibly stimulate microbial activity (as found in increased respiration rates), and might lead to increased nitrogen losses if the more quickly mineralized nitrogen is not taken up by the plants.

Effects of no-tillage on greenhouse gas emissions in maize fields in a semi-humid temperate climate region

Agricultural tillage practices have a significant impact on the generation and consumption of greenhouse gases (GHGs), the primary causes of global warming. Two tillage systems, conventional tillage (CT) and no-tillage (NT), were compared to evaluate their effects on GHG emissions in this study. Averaged from 2018 to 2020, significant decreases of CO₂ and N₂O emissions by 7.4% and 51.1% were observed in NT as compared to those of CT. NT was also found to inhibit the soil CH₄ uptake. In this study, soil was a source of CO₂ and N₂O but a sink for CH₄. The effect of soil temperature on the fluxes of CO₂ was more pronounced than that of soil moisture. However, soil temperature and soil moisture had a weak correlation with CH₄ and N₂O flux variations. As compared to CT, NT did not affect maize yields but significantly reduced global warming potential (GWP) by 8.07%. For yield-scaled GWP, no significant difference was observed in NT (9.63) and CT (10.71). Taken together, NT was an environment-friendly tillage practice to mitigate GHG emissions in the soil under the tested conditions.

Physiological and transcription level responses of microalgae Auxenochlorella protothecoides to cold and heat induced oxidative stress

Temperature is a crucial factor affecting microalgae CO₂ capture and utilization. However, an in-depth understanding of how microalgae respond to temperature stress is still unclear. In particular, the regulation mechanism under opposite temperature (heat and cold) stress had not yet been reported. In this study, the physicochemical properties and transcription level of related genes of microalgae Auxenochlorella protothecoides UTEX 2341 under heat and cold stress were investigated. Heat stress (Hs) caused a drastic increase of reactive oxygen species (ROS) in UTEX 2341. As key elements responded to Hs, superoxide dismutase (SOD) enzyme increased by 150%, 70%, and 30% in activity, and nitric oxide (NO) grew by 409.6%, 212.5%, and 990.4% in content compared with the control at 48 h, 96 h, 168 h. Under cold stress (Cs), ROS increased in the early stage and decreased in the later stage. As key factors responded to Cs, proline (Pro) increased respectively by 285%, 383%, and 81% in content, and heat shock transcriptional factor HSFA1d increased respectively by 161%, 71%, and 204% in transcript level compared with the control at 48 h, 96 h, 168 h. Furthermore, the transcript level of antioxidant enzymes or antioxidant coding genes was consistent with the changing trend of enzymes activity or antioxidant content. Notably, both glutathione (GSH) and heat shock protein 97 (hsp 97) were up-regulated in response to Hs and Cs. In conclusion, GSH and hsp 97 were the core elements of UTEX 2341 in response to both Hs and Cs. SOD and NO were the key elements that responded to Hs, while proline and HSFA1d were the key elements that responded to Cs. This study provided a basis for the understanding of the response mechanism of microalgae under temperature stress and the improvement of the microalgae tolerance to temperature stress.

Effects of Fertilization on Morphological and Physiological Characteristics and Environmental Cost of Maize (Zea mays L.)

Maize (Zea mays L.) is one of the most important crops in the world and fertilization is the most important management practice which contributes to high yield. The objective of this study was to determine the effect of different fertilizers on maize crop and their contribution to the carbon footprint. The experiments were conducted in a commercial field in the area of Thessaloniki during the growing seasons of 2019 and 2020. During the experiment a number of physiological and morphological characteristics, and the energy output/input ratio, energy efficiency, and carbon footprint were determined. The results of the experiment showed that the inorganic fertilizers and manure improved the morphological and physiological characteristics that were studied compared to the green manure treatment and the control. In addition, it appeared most of the energy input of maize cultivation is from fertilizers (52%), followed by diesel (25%) and the use of machinery (14%). The treatments with the slow release fertilizers and the manure gave satisfactory results with an average of 42.1 Mg ha−1 in 2019 and 43.6 Mg ha−1 in 2020 for both fertilization treatments. Therefore, it is necessary to use the appropriate fertilizers in order to maintain the productivity of the crop and reduce the environmental costs.

Short-Term Responses of Soil Microbial Communities to Changes in Air Temperature, Soil Moisture and UV Radiation

We analyzed the effects on a soil microbial community of short-term alterations in air temperature, soil moisture and ultraviolet radiation and assessed the role of invertebrates (species Enchytraeus crypticus) in modulating the community’s response to these factors. The reference soil, Lufa 2.2, was incubated for 48 h, with and without invertebrates, under the following conditions: standard (20 °C + 50% water holding capacity (WHC)); increased air temperature (15–25 °C or 20–30 °C + 50% WHC); flood (20 °C + 75% WHC); drought (20 °C + 25% WHC); and ultraviolet radiation (UV) (20 °C + 50% WHC + UV). BIOLOG EcoPlates and 16S rDNA sequencing (Illumina) were used to assess the microbial community’s physiological profile and the bacterial community’s structure, respectively. The bacterial abundance (estimated by 16S rDNA qPCR) did not change. Most of the conditions led to an increase in microbial activity and a decrease in diversity. The structure of the bacterial community was particularly affected by higher air temperatures (20–30 °C, without E. crypticus) and floods (with E. crypticus). Effects were observed at the class, genera and OTU levels. The presence of invertebrates mostly resulted in the attenuation of the observed effects, highlighting the importance of considering microbiome–invertebrate interactions. Considering future climate changes, the effects described here raise concern. This study provides fundamental knowledge to develop effective strategies to mitigate these negative outcomes. However, long-term studies integrating biotic and abiotic factors are needed.

Remotely Monitoring Vegetation Productivity in Two Contrasting Subtropical Forest Ecosystems Using Solar-Induced Chlorophyll Fluorescence

Subtropical forests can sequester a larger amount of atmospheric carbon dioxide (CO2) relative to other terrestrial ecosystems through photosynthetic activity and act as an important role in mitigating global climate warming. Compared with the model-based gross primary production (GPP) products, satellite-derived solar-induced fluorescence (SIF) opens a new window for quantification. Here, we used the remotely sensed SIF retrievals, two satellite-driven GPP products including MODIS (GPPMOD) and BESS (GPPBESS), and tower-based GPP measurements at two contrasting subtropical forests to provide a systematic analysis. Our results revealed that GPP and the associated environmental factors exhibited distinct seasonal patterns. However, the peak GPP values had large differences, with stronger GPP in the evergreen needleleaf forest site (8.76 ± 0.71 g C m−2 d−1) than that in the evergreen broadleaf forest site (5.71 ± 0.31 g C m−2 d−1). The satellite-derived SIF retrievals showed great potential in quantifying the variability in GPP, especially for the evergreen needleleaf forest with r reaching up to 0.909 (p < 0.01). GPPMOD and GPPBESS showed distinctly different performances for the two subtropical forests, whereas the GPP estimates by exclusive use of satellite-based SIF data promised well to the tower-based GPP observations. Multi-year evaluation again confirmed the good performance of the SIF-based GPP estimates. These findings will provide an alternative framework for quantifying the magnitude of forest GPP and advance our understanding of the carbon sequestration capacity of subtropical forest ecosystems.

Preparation of Butadiene-Bridged Polymethylsiloxane/Ethylcellulose/1-Carboxymethyl-3-methylimidazolium Chloride Ternary Composite Membranes for Gas Separation

Excessive CO2 emissions have resulted in global warming and are a serious threat to the life of people, various strategies have been implemented to cut carbon emissions, and one of them is the use of a gas separation membrane to capture CO2 effectively. In this experiment, the butadiene-bridged polymethylsiloxane (BBPMS)/ethyl cellulose (EC)/ionic liquid (IL) ternary composite membranes were prepared by EC as a substrate, BBPMS, and IL as additives in tetrahydrofuran under high-speed stirring and coated on the membrane. The membrane structure was characterized by a Fourier transform infrared spectrometer and scanning electron microscope, and the membrane properties were tested by a membrane tensile strength tester, thermal weight loss analyzer, and gas permeability meter. The results show that the surface of the ternary composite membrane is dense and flat with a uniform distribution, and the membrane formation, heat resistance, and mechanical properties are good. The permeability coefficient of the ternary composite membrane for CO2 reached 1806.03 Barrer, which is 20.00 times higher than that of the EC/IL hybrid matrix membrane. The permeability coefficient of O2 reached 321.01 Barrer, which is 19.21 times higher than that of the EC/IL membrane. When the doping amount of BBPMS is 70-80%, the O2/N2 gas permeation separation of the BBPMS/EC/IL ternary composite membrane is close to the Robertson 2008 curve. It is always known that in the gas separation process the membrane material is the most crucial factor. The success of this experiment points to a new direction for the preparation of new membrane materials.

Do soil conservation practices exceed their relevance as a countermeasure to greenhouse gases emissions and increase crop productivity in agriculture?

Globally, agriculture sector is the significant source of greenhouse gases (GHGs) emissions into the atmosphere. To achieve the goal of limiting or mitigating these emissions, a rigorous abatement strategy with an additional focus on improving crop productivity is now imperative. Replacing traditional agriculture with soil conservation-based farming can have numerous ecological benefits. However, most assessments only consider improvements in soil properties and crop productivity, and often preclude the quantitative impact analysis on GHGs emissions. Here, we conducted a meta-analysis to evaluate crop productivity (i.e., biomass, grain, total yield) and GHGs emissions (i.e., CO₂, N₂O, CH₄) for three major soil conservation practices i.e., no-tillage, manures, and biochar. We also examined the yield potential of three major cereal crops (i.e., wheat, rice, maize) and their significance in mitigating GHGs emissions. None of the manures were able to reduce GHGs emissions, with poultry manure being the largest contributor to all GHGs emissions. However, pig-manure had the greatest impact on crop yield while emitting the least CO₂ emissions_. Use of biochar showed a strong coupling effect between reduction of GHGs (i.e., CH₄ by -37%; N₂O by -25%; CO₂ by -5%) and the increase in crop productivity. In contrast, no-tillage resulted in higher GHGs emissions with only a marginal increase in grain yield. Depending on crop type, all cereal crops showed varied degrees of GHGs mitigation under biochar application, with wheat responding most strongly due to the additional yield increment. The addition of biochar significantly reduced CO₂ and N₂O emissions under both rainfed and irrigated conditions, although CH₄ reductions were identical in both agroecosystems. Interestingly, the use of biochar resulted in a greater yield benefit in rainfed than in irrigated agriculture. Despite significant GHGs emissions, manure application contributed to higher crop yields, regardless of soil type or agroecosystem. Moreover, no-tillage showed a significant reduction in CH₄ and N₂O emissions under rainfed and irrigated conditions. Notably , biochar application in coarse while no-till in fine textured soils contributed to N₂O mitigation. Most importantly, effectiveness of no-tillage as a countermeasure to GHGs emissions while providing yield benefits is inconsistent. Overall, the decision to use farm manures should be reconsidered due to higher GHGs emissions. We conclude that the use of biochar could be an ideal way to reduce GHGs emissions. However, further understanding of the underlying mechanisms and processes affecting GHGs emissions is needed to better understand the feedback effects in conservation agriculture.

Estimation of the Tower Shape Effect on the Stress–Strain Behavior of Wind Turbines Operating under Offshore Boundary Conditions

The metal tower, or the pylon, is one of the most important elements in the construction of a wind turbine. It has the role of supporting the entire wind turbine, and it also allows access for inspection and conducting planned maintenance and repairs. Moreover, the tower ensures support for the structure and strengthens the whole assembly. It has a particularly important role, as it has to face very severe weather conditions. The present study aims to analyze the forces and moments resulting from the action of the wind on the tower of a wind turbine. Two important load cases are considered, namely, the load under operating conditions and the ultimate load under 50 year wind conditions. For this purpose, cylindrical and conical geometric shapes of the tower were chosen. These were analyzed under the action of both normal and extreme wind speeds. Then, the behavior of the two towers under the action of the wind speed for a location in the Black Sea was analyzed. Finally, in an attempt to make the structure more economical, the thickness of the shell was reduced.

Current and future threats to human health in the Anthropocene

It has been widely recognised that the threats to human health from global environmental changes (GECs) are increasing in the Anthropocene epoch, and urgent actions are required to tackle these pressing challenges. A scoping review was conducted to provide an overview of the nine planetary boundaries and the threats to population health posed by human activities that are exceeding these boundaries in the Anthropocene. The research progress and key knowledge gaps were identified in this emerging field. Over the past three decades, there has been a great deal of research progress on health risks from climate change, land-use change and urbanisation, biodiversity loss and other GECs. However, several significant challenges remain, including the misperception of the relationship between human and nature; assessment of the compounding risks of GECs; strategies to reduce and prevent the potential health impacts of GECs; and uncertainties in fulfilling the commitments to the Paris Agreement. Confronting these challenges will require rigorous scientific research that is well-coordinated across different disciplines and various sectors. It is imperative for the international community to work together to develop informed policies to avert crises and ensure a safe and sustainable planet for the present and future generations.

GHGs Emission from the Agricultural Sector within EU-28: A Multivariate Analysis Approach

Climate mitigation and adaptation planning (CMAP) has recently been implemented across the EU-28 to reduce GHG emissions (CO2, CH4, N2O). Thus, the aim of this study was to provide an overview of GHG emissions from the agricultural sector in the EU-28 from 1990 to 2019, and cluster the EU-28 countries regarding their total GHG emissions. The results emphasize the positive impact of CMAP through a negative trend of the total GHG emissions (−2653.01 thousand tons/year, p < 0.05). Despite the positive and not significant trend of the total CO2 emissions, both CH4 and N2O exhibited a negative and significant trend. At the country scale, Italy, the United Kingdom, and the Netherlands showed the highest reduction in total GHG emissions, by −282.61thousand tons/year (p < 0.05), −266.40 thousand tons/year (p < 0.05), and −262.91 thousand tons/year (p < 0.05), respectively. The output of the multivariate analysis approach indicates changes in the pattern of GHG emissions between 1990 and 2019, where CO2 emissions decreased in the case of Poland and Czechia. The output of this study highlights the positive impact of CMAP, adopted by EU countries, in minimizing GHG emissions. Despite some fluctuations in CO2 emissions, strategies for attaining carbon neutrality in the agricultural sector, across the European Union, should be pursued.

Effects of biological nitrification inhibitors on nitrogen use efficiency and greenhouse gas emissions in agricultural soils: A review

To maintain and increase crop yields, large amounts of nitrogen fertilizers have been applied to farmland. However, the nitrogen use efficiency (NUE) of chemical fertilizer remains very low, which may lead to serious environmental problems, including nitrate pollution, air quality degradation and greenhouse gas (GHG) emissions. Nitrification inhibitors can alleviate nitrogen loss by inhibiting nitrification; thus, biological nitrification inhibition by plants has gradually attracted increasing attention due to its low cost and environmental friendliness. Research progress on BNI is reviewed in this article, including the source, mechanisms, influencing factors and application of BNIs. In addition, the impact of BNI on agriculture and GHG emissions is summarized from the perspective of agricultural production and environmental protection, and the key future research prospects of BNIs are also noted.

Selection and performance estimation of Green Lean Six Sigma Projects: a hybrid approach of technology readiness level, data envelopment analysis, and ANFIS

Nowadays budget and schedule constraints have forced organizations to select six sigma projects based on pre-defined success criteria. Also, progressive approaches based on green and lean paradigm are vital for companies to enhance their social and environmental performance. Then, Green Lean Six Sigma (GLS) projects play the main role in improving the performance of an organization while augmenting its sustainability. Accordingly in this paper, past studies were reviewed, and GLS projects' indicators and performance evaluation criteria were identified. Data envelopment analysis (DEA) was employed for the appropriate selection of GLS projects. Next, the ranking and performance weight of each project were investigated, and also the projects were categorized based on the technology readiness level (TRL). Additionally, an adaptive neuro-fuzzy inference system (ANFIS) method was applied for the successful prediction of selected GLS projects. Twenty-eight inputs and 9 outputs for the first project category (with TRL 9) and 28 inputs and 6 outputs for the second project category (with TRL 8) were entered into the model. The statistical assessment measures such as Nash-Sutcliffe efficiency (NSE), root mean squared of error (RMSE), mean absolute error (MAE), and R2 were employed for capability appraisal of ANFIS model. Results of NSE and R2 indicators for both project categories were 1.00 that proved the efficiency of the ANFIS model for success prediction of GLS projects. Also, RMSE and MAE indicators for category 1 were 0.01 and 0.02 respectively. Similarly, these measures for category 2 were 0.02 and 0.02. The results advocate a proper approximation for observed values by the ANFIS model. Also, the results indicated that TRL as an important enabler of the GLS project has a meaningful role in the performance of GLS projects.

Nitrous oxide emission from agricultural soils: Application of animal manure or biochar? A global meta-analysis

Organic amendments (animal manure and biochar) to agricultural soils may enhance soil organic carbon (SOC) contents, improve soil fertility and crop productivity but also contribute to global warming through nitrous oxide (N₂O) emission. However, the effects of organic amendments on N₂O emissions from agricultural soils seem variable among numerous research studies and remains uncertain. Here, eighty-five publications (peer-reviewed) were selected to perform a meta-analysis study. The results of this meta-analysis study show that the application of animal manure enhanced N₂O emissions by 17.7%, whereas, biochar amendment significantly mitigated N₂O emissions by 19.7%. Moreover, coarse textured soils increased [lnRR‾ = 182.6%, 95% confidence interval (CI) = 151.4%, 217.7%] N₂O emission after animal manure, in contrast, N₂O emission mitigated by 7.0% from coarse textured soils after biochar amendment. In addition, this study found that 121-320 kg N ha^-1 and ⩽ 30 T ha^-1 application rates of animal manure and biochar mitigated N₂O emissions by 72.3% and 22.5%, respectively. Soil pH also played a vital role in regulating the N₂O emissions after organic amendments. Furthermore, > 10 soil C: N ratios increased N₂O emissions by 121.4% and 27.6% after animal and biochar amendments, respectively. Overall, animal manure C: N ratios significantly enhanced N₂O emissions, while, biochar C: N ratio had not shown any effect on N₂O emissions. Overall, average N₂O emission factors (EFs) for animal manure and biochar amendments were 0.46% and -0.08%, respectively. Thus, the results of this meta-analysis study provide scientific evidence about how organic amendments such as animal manure and biochar regulating the N₂O emission from agricultural soils.

Carbon stocks of homestead forests have a mitigation potential to climate change in Bangladesh

A total of 176 homestead forests at three altitudes in the Chittagong Hill Tracts, Bangladesh were randomly surveyed to estimate carbon (C) stocks and how stand structure affects the biomass C. All woody vegetations were measured, and litter and soil (0-30 cm depth) were sampled. The tree biomass C stock in the top two altitude forests was up to 37-48% higher than in low altitude, owing to significantly higher tree density and species diversity. An increase in species diversity index by one unit increased the biomass stock by 23 Mg C ha^-1. The C stock of litterfall in low altitude forests was 22-28% higher than in the top two altitude due to the deposition of litters downslope and deliberate use of mulch for soil improvement and conservation, resulting in up to 5% higher total soil C. The topsoil C was 10-25% higher than the deeper soil, depending on the altitude. The forest stored 89 Mg C ha^-1, indicating a potential for C sequestration in trees outside forest. This study would help policymakers to strengthen the recognition of small-scale forests for mitigation in REDD + (reducing emissions from deforestation and forest degradation, the role of conservation, sustainable management of forests, and enhancement of forest carbon stocks) and support owners through C credits from sustainably managed forests.

Long-term fertilization affects functional soil organic carbon protection mechanisms in a profile of Chinese loess plateau soil

Crop productivity and soil health are limited by organic carbon (OC), however, the variations in the mechanisms of SOC preservation in a complete soil profile subjected to long-term fertilization remains unclear. The objective of the study was to examined the content and profile distribution of the distinctive SOC protection mechanisms on a complete profile (0-100 cm) of Eumorthic Anthrosols in Northwest China after 23 years of chemical and manure fertilization. The soil was fractionated by combined physical-chemical and density floatation techniques. Throughout the profile, significant variations were observed among fractions. In the topsoil (0-20 and 20-40 cm), mineral coupling with the fertilization of manure (MNPK) enhanced total SOC content and recorded for 29% of SOC in the 0-20 and 20-40 cm layers. Moreover, MNPK increased the SOC content of the unprotected cPOC fraction by 60.9% and 61.5% in the 0-20 and 20-40 cm layer, while SOC content was low in the subsoil layers (40-60, 60-80 and 80-100 cm, respectively) compared with the control (C). The highest OC under MNPK in physically protected micro-aggregates (μagg) (6.36 and 6.06 g C kg^-1), and occluded particulate organic carbon (iPOC) (1.41 and 1.29 g C kg^-1) was found in the topsoil layers. The unprotected cPOC fraction was the greatest C accumulating fraction in the topsoil layers, followed by μagg and H-μSilt fractions in the soil profile, implying that these fractions were the most sensitive to the fertilization treatments. Overall, the unprotected, physically protected, and physico-chemically protected fractions were the dominant fractions for the sequestration of carbon across fertilization treatments and soil layers.

A global meta-analysis of greenhouse gases emission and crop yield under no-tillage as compared to conventional tillage

No-tillage (NT) practice is extensively adopted with aims to improve soil physical conditions, carbon (C) sequestration and to alleviate greenhouse gases (GHGs) emissions without compromising crop yield. However, the influences of NT on GHGs emissions and crop yields remains inconsistent. A global meta-analysis was performed by using fifty peer-reviewed publications to assess the effectiveness of soil physicochemical properties, nitrogen (N) fertilization, type and duration of crop, water management and climatic zones on GHGs emissions and crop yields under NT compared to conventional tillage (CT) practices. The outcome reveals that compared to CT, NT increased CO₂, N₂O, and CH₄ emissions by 7.1, 12.0, and 20.8%, respectively. In contrast, NT caused up to 7.6% decline in global warming potential as compared to CT. However, absence of difference in crop yield was observed both under NT and CT practices. Increasing N fertilization rates under NT improved crop yield and GHGs emission up to 23 and 58%, respectively, compared to CT. Further, NT practices caused an increase of 16.1% CO₂ and 14.7% N₂O emission in the rainfed areas and up to 54.0% CH₄ emission under irrigated areas as compared to CT practices. This meta-analysis study provides a scientific basis for evaluating the effects of NT on GHGs emissions and crop yields, and also provides basic information to mitigate the GHGs emissions that are associated with NT practice.

Environmental Sustainability Enhancement of Waste Disposal Sites in Developing Countries through Controlling Greenhouse Gas Emissions

Sustainable management of municipal solid waste is one of the major challenges for authorities in developing countries. Current waste disposal methods in Pakistan and other developing countries are not meeting standards of any proper waste management system opted for in the developed world. This mismanagement of waste is leading to serious environmental problems at local as well as global levels. This study aims to investigate the methane emissions from waste dumpsites in the city of Karachi, Pakistan, and to propose an effective approach to enhance their environmental sustainability. The methane emissions from waste disposal sites were assessed by simulating four different landfill situations during the landfill simulation reactor experiment. The residual methane reduction potential of each waste disposal approach was assessed by a biochemical methane test of waste after the experiment. It is estimated that in the present situation, about 11,500 tons of CO2-eq methane is released annually from waste disposal sites in Karachi. The convectional anaerobic landfill with methane capturing facilities and post-aeration operation was found to be the most environmentally sustainable approach with controlling 65% of residual methane emissions in comparison with the present scenario. For the development of new landfill sites, we recommend the bioreactor landfill approach with methane recovery and post-care (in-situ aeration).