Search Results (42)

Understanding the influence of tree species and their intrinsic traits on biochar yield and carbon retention is essential for optimizing the conversion of biomass to biochar in carbon-negative systems. While it is well-established that pyrolysis temperature and broad feedstock categories significantly affect biochar properties, the extent of species-level variation within woody biomass under standardized pyrolysis conditions remains insufficiently quantified. Here, we synthesized biochar from seven common subtropical tree species at 600 °C under oxygen-limited smoldering conditions and quantified three key indices: biochar yield (Y), carbon recovery efficiency (ηC), and carbon enrichment factor (EC). We further examined the relationships of these indices with feedstock characteristics (initial carbon content, wood density) and functional group identity (conifer vs. broadleaf). Analysis of variance revealed significant interspecific differences in ηC but weaker effects on Y, indicating that species identity primarily governs carbon retention rather than total mass yield. Broadleaf species (Liquidambar formosana, Castanea mollissima) exhibited consistently higher ηC and EC than conifers (Pinus massoniana, P. elliottii), reflecting higher lignin content and wood density that favor aromatic char formation. Principal component and cluster analyses clearly separated coniferous and broadleaf taxa, accounting for over 80% of total variance in carbon-related traits. Regression models showed that feedstock carbon content, biochar carbon content, and wood density together explained 15.5% of the variance in ηC, with feedstock carbon content exerting a significant negative effect, whereas wood density correlated positively with carbon retention. These findings demonstrate that tree species and their functional traits jointly determine carbon fixation efficiency during smoldering. High initial carbon content alone does not guarantee enhanced carbon recovery; instead, wood density and lignin-derived structural stability dominate retention outcomes. Our results underscore the need for trait-based feedstock selection to improve biochar quality and carbon sequestration potential, and provide a mechanistic framework linking species identity, functional traits, and carbon stabilization in biochar production. Full article

Rapid urban expansion has heightened the demand for accurate, scalable, and real-time methods to assess tree health and the provision of ecosystem services. Urban trees are the major contributors to air-quality improvement and climate change mitigation; however, their monitoring is mostly constrained to inherently subjective and inefficient manual inspections. In order to break this barrier, we put forward a lightweight multimodal deep-learning framework that fuses RGB imagery with environmental and biometric sensor data for a combined evaluation of tree-health condition as well as the estimation of the daily oxygen production and CO₂ absorption. The proposed architecture features an EfficientNet-B0 vision encoder upgraded with Mobile Inverted Bottleneck Convolutions (MBConv) and a squeeze-and-excitation attention mechanism, along with a small multilayer perceptron for sensor processing. A common multimodal representation facilitates a three-task learning set-up, thus allowing simultaneous classification and regression within a single model. Our experiments with a carefully curated dataset of segmented tree images accompanied by synchronized sensor measurements show that our method attains a health-classification accuracy of 92.03% while also lowering the regression error for O₂ (MAE = 1.28) and CO₂ (MAE = 1.70) in comparison with unimodal and multimodal baselines. The proposed architecture, with its 5.4 million parameters and an inference latency of 38 ms, can be readily deployed on edge devices and real-time monitoring platforms. Full article

Accounting for Gross Ecosystem Product (GEP) is a crucial approach for quantifying ecological value, assessing the contributions of ecosystems to human well-being, and supporting sustainable development decision-making. For the Pingtan Comprehensive Experimental Zone, an island-centered administrative region, we developed a GEP indicator system and accounting framework tailored to islands for integrated accounting of terrestrial and marine ecosystems. We used a functional value approach that combines biophysical models with statistical data and conducts physical and monetary accounting in two steps. The accounting methods and procedures were refined to exclude resource and labor inputs from production processes and eliminate external contributions. From 2015 to 2023, the GEP increased by 9.118 billion CNY, representing an increase of 133.03%. The total GEP exhibited a phased rapid–slow–rapid fluctuation pattern over time. The value structure shifted from being dominated by material supply services to being dominated by cultural services. The high-value areas of flood regulation exhibited a clear expansion trend, whereas water conservation and climate regulation showed a fragmented decline. Carbon sequestration, oxygen release, and soil retention remained relatively stable. The findings support evaluating the effectiveness of ecological conservation, implementing ecological compensation, and formulating sustainable development policies in the Pingtan Comprehensive Experimental Zone. Full article

The rapid urbanization process has led to deteriorating air quality and elevated carbon dioxide levels, highlighting an urgent need for effective urban greening strategies. This study aims to quantify and compare the air pollution removal (APR), carbon sequestration (CS), and oxygen production (OP) capacities of different green space renovation plans in residential areas of a typical arid to semi-arid city in Northwest China. Using the i-Tree Eco model, we simulated the ecological benefits of various vegetation configurations. Our results demonstrated that tree species selection is a critical determinant of ecological performance. Ligustrum (Privet), Magnolia, and Populus (Poplar) were identified as the predominant species, exhibiting distinct effectivities in providing these services. Specifically, we found that species with high APR and CS efficiencies should be prioritized for green space renewal in this water-limited region. Correlation analysis revealed that both APR and CS capacities were most strongly correlated with vegetation greenness, followed by species identity. In contrast, the planning layout of vegetation showed no significant correlation with greenness. For OP, tree species was the most influential factor, ahead of vegetation quantity. This study provides a scientific basis for optimizing plant species selection and spatial arrangement in urban greening projects, offering practical guidance for enhancing ecological benefits in arid and semi-arid cities undergoing renewal. Full article

Orchard grass intercropping offers a promising strategy to mitigate forage scarcity and boost fruit yield. However, its applicability in high-altitude regions such as the Xizang Plateau remains poorly understood. During the four-year experiment, the ecosystem service values (ESV) of an apple orchard intercropped with different grass species in Linzhi, southeast Xizang, were investigated in order to assess the applicability of orchard grass planting at high altitudes and identify optimal grass species combinations. Seven treatments were established, including six artificial grass systems (annual legume, annual gramineous, annual legume + gramineous, perennial legume, perennial gramineous, perennial legume + gramineous) and a natural grass control group. Results showed that artificial grass systems, particularly perennial ones, yielded higher total ESV than the natural grass control. Perennial grasses outperformed annual grasses and natural grass in provisioning services (with higher fruit and forage yields) and regulating services (with enhanced carbon sequestration and oxygen production). However, perennial grasses also led to reduced supporting services, primarily due to decreased soil nutrient availability (especially available phosphorus and potassium) and lower plant diversity. The optimal treatments were Dactylis glomerata monoculture and Medicago sativa + D. glomerata mixed culture, which achieved the highest total ESV. Notably, the nutrient depletion observed in perennial grass treatments highlighted the need for supplemental fertilization to ensure long-term sustainability of the system. In conclusion, artificial orchard grass systems significantly enhanced total net ESV in high-altitude regions, whereas individual ecosystem services demonstrated divergent responses to different grass species. Specifically, D. glomerata monoculture and M. sativa + D. glomerata intercropping emerged as the optimal orchard grass patterns in Linzhi. To maintain long-term orchard productivity, adaptive fertilizer management strategies are recommended to counteract potential soil nutrient depletion associated with these grass cultivation systems. Full article

Torrefaction, a mild thermochemical pretreatment process, is widely acknowledged as an effective strategy for enhancing the energy potential of lignocellulosic biomass. This review systematically evaluates the technological, environmental, and economic dimensions of lignocellulosic biomass torrefaction with the objective of clarifying its critical role in sustainable energy production and circular economy frameworks. Drawing from recent literature, the review covers process fundamentals, feedstock characteristics and operational parameters—typically 200–300 °C, heating rates below 50 °C per minute, ~1 h residence time, and oxygen-deficient conditions. The impacts of torrefaction on fuel properties, such as increased energy density, improved grindability and pelletability, enhanced storage stability, and reduced microbial degradation are critically assessed along with its contribution to waste valorization and renewable energy conversion. Particular emphasis is placed on the application of torrefied biomass (biochar) in sustainable agriculture, where it can enhance nutrient retention, improve soil quality and promote long-term carbon sequestration. This review identifies an unresolved research gap in aligning large-scale techno-economic feasibility with environmental impacts, specifically concerning the high process energy requirements, emission mitigation and regulatory integration. Process optimization, reactor design and supportive policy frameworks are identified as key strategies that could significantly improve the economic viability and sustainability outcomes. Overall, torrefaction demonstrates substantial potential as a scalable pathway for converting waste agricultural and forest residues into carbon-neutral biofuels. By effectively linking biomass waste valorization with renewable energy production and sustainable agricultural practices, this review offers a practical route to reducing environmental impacts while supporting the broader objectives of the global circular economy. Full article

Driven by the “dual carbon” goal, virtual power plants (VPPs) are the core vehicle for integrating distributed energy resources, but the multiple uncertainties in wind power, electricity/heat load, and electricity price, coupled with the impact of carbon-trading cost, make it difficult for traditional scheduling methods to balance the robustness and economy of VPPs. Therefore, this paper proposes an oxy-fuel combustion capture (OCC)-VPP architecture, integrating an OCC unit to improve the energy efficiency of the system through the “electricity-oxygen-carbon” cycle. Ten typical scenarios are generated by Latin hypercube sampling and K-means clustering to describe the uncertainties of source and load probability distribution, combined with the polyhedral uncertainty set to delineate the boundary of source and load fluctuations, and the stepped carbon-trading mechanism is introduced to quantify the cost of carbon emission. Then, a three-stage stochastic–robust scheduling model is constructed. The simulation based on the arithmetic example of OCC-VPP in North China shows that (1) OCC-VPP significantly improves the economy through the synergy of electric–hydrogen production and methanation (52% of hydrogen is supplied with heat and 41% is methanated), and the cost of carbon sequestration increases with the prediction error, but the carbon benefit of stepped carbon trading is stabilized at the base price of 320 DKK/ton; (2) when the uncertainty is increased from 0 to 18, the total cost rises by 45%, and the cost of purchased gas increases by the largest amount, and the cost of energy abandonment increases only by 299.6 DKK, which highlights the smoothing effect of energy storage; (3) the proposed model improves the solution speed by 70% compared with stochastic optimization, and reduces cost by 4.0% compared with robust optimization, which balances economy and robustness efficiently. Full article

Soil organic matter (SOM) decomposition is a critical biogeochemical process that regulates the carbon cycle, nutrient availability, and agricultural sustainability of cropland systems. Recent progress in multi-omics and microbial network analyses has provided us with a better understanding of the decomposition process at different spatial and temporal scales. Climate factors, such as temperature and seasonal variations in moisture, play a critical role in microbial activity and enzyme kinetics, and their impacts are mediated by soil physical and chemical properties. Soil mineralogy, texture, and structure create different soil microenvironments, affecting the connectivity of microbial habitats, substrate availability, and protective mechanisms of organic matter. Moreover, different microbial groups (bacteria, fungi, and archaea) contribute differently to the decomposition of plant residues and SOM. Recent findings suggest the paramount importance of living microbial communities as well as necromass in forming soil organic carbon pools. Microbial functional traits such as carbon use efficiency, dormancy, and stress tolerance are essential drivers of decomposition in the soil. Furthermore, the role of microbial necromass, alongside live microbial communities, in the formation and stabilization of persistent SOM fractions is increasingly recognized. Based on this microbial perspective, feedback between local microbial processes and landscape-scale carbon dynamics illustrates the cross-scale interactions that drive agricultural productivity and regulate soil climate. Understanding these dynamics also highlights the potential for incorporating microbial functioning into sustainable agricultural management, which offers promising avenues for increasing carbon sequestration without jeopardizing soil nutrient cycling. This review explores current developments in intricate relationships between climate, soil characteristics, and microbial communities determining SOM decomposition, serving as a promising resource in organic fertilization and regenerative agriculture. Specifically, we examine how nutrient availability, pH, and oxygen levels critically influence these microbial contributions to SOM stability and turnover. Full article

Over recent decades, coastal wetlands in Jiangsu Province have faced multiple challenges, including overfishing, reclamation for aquaculture, wetland shrinkage, and biodiversity loss. Implementing wetland ecological restoration proves crucial for mitigating the degradation of coastal wetland ecosystems. Quantifying ecosystem service values and establishing rational ecological compensation standards provide essential references for ecological compensation research and alleviating human–land conflicts. The Jianchuan Ecological Restoration Project, located in Dafeng District of Yancheng City, Jiangsu Province, employs integrated wetland, woodland, and farmland construction to rebuild biodiversity, enhance water conservation capacity, and improve water purification functions, thereby significantly boosting regional ecological services. Results have demonstrated that the total ecosystem service value of this project reaches CNY 76.2896 million, with climate regulation representing the highest value (CNY 68.1496 million, 89.33% of total). Subsequent values include biodiversity maintenance (3.40%), water purification (3.31%), and food production (2.95%), while carbon sequestration/oxygen release (0.96%) and soil retention (0.05%) show relatively lower contributions. Notably, this project innovatively integrates carbon finance mechanisms through “carbon sink loans”, achieving efficient transformation of ecological value from “paper accounts” to market realization. This study establishes a scientific foundation for ecological restoration projects through ecosystem service-based value assessment and pathway exploration, offering both theoretical framework and practical references. Full article

Against the backdrop of global energy transition and strict environmental regulations, supercritical carbon dioxide (scCO₂) fracturing and oil displacement technologies have emerged as pivotal green approaches in shale gas exploitation, offering the dual advantages of zero water consumption and carbon sequestration. However, the inherent low viscosity of scCO₂ severely restricts its sand-carrying capacity, fracture propagation efficiency, and oil recovery rate, necessitating the urgent development of high-performance thickeners. The current research on scCO₂ thickeners faces a critical trade-off: traditional fluorinated polymers exhibit excellent philicity CO₂, but suffer from high costs and environmental hazards, while non-fluorinated systems often struggle to balance solubility and thickening performance. The development of new thickeners primarily involves two directions. On one hand, efforts focus on modifying non-fluorinated polymers, driven by environmental protection needs—traditional fluorinated thickeners may cause environmental pollution, and improving non-fluorinated polymers can maintain good thickening performance while reducing environmental impacts. On the other hand, there is a commitment to developing non-noble metal-catalyzed siloxane modification and synthesis processes, aiming to enhance the technical and economic feasibility of scCO₂ thickeners. Compared with noble metal catalysts like platinum, non-noble metal catalysts can reduce production costs, making the synthesis process more economically viable for large-scale industrial applications. These studies are crucial for promoting the practical application of scCO₂ technology in unconventional oil and gas development, including improving fracturing efficiency and oil displacement efficiency, and providing new technical support for the sustainable development of the energy industry. This study innovatively designed an amphiphilic modified amino silicone oil polymer (MA-co-MPEGA-AS) by combining maleic anhydride (MA), methoxy polyethylene glycol acrylate (MPEGA), and amino silicone oil (AS) through a molecular bridge strategy. The synthesis process involved three key steps: radical polymerization of MA and MPEGA, amidation with AS, and in situ network formation. Fourier transform infrared spectroscopy (FT-IR) confirmed the successful introduction of ether-based CO₂-philic groups. Rheological tests conducted under scCO₂ conditions demonstrated a 114-fold increase in viscosity for MA-co-MPEGA-AS. Mechanistic studies revealed that the ether oxygen atoms (Lewis base) in MPEGA formed dipole–quadrupole interactions with CO₂ (Lewis acid), enhancing solubility by 47%. Simultaneously, the self-assembly of siloxane chains into a three-dimensional network suppressed interlayer sliding in scCO₂ and maintained over 90% viscosity retention at 80 °C. This fluorine-free design eliminates the need for platinum-based catalysts and reduces production costs compared to fluorinated polymers. The hierarchical interactions (coordination bonds and hydrogen bonds) within the system provide a novel synthetic paradigm for scCO₂ thickeners. This research lays the foundation for green CO₂-based energy extraction technologies. Full article

Soil degradation has been accelerating globally due to climate change, which threatens food production, biodiversity, and ecosystem balance. Traditional soil restoration strategies are often expensive, slow, or unsustainable in the long term. In this context, cyanobacteria have emerged as promising biotechnological alternatives, being the only prokaryotes capable of performing oxygenic photosynthesis. Moreover, they can capture atmospheric carbon and nitrogen, release exopolysaccharides (EPSs) that stabilize the soil, and facilitate the development of biological soil crusts (biocrusts). In recent years, the convergence of multi-omics tools, such as metagenomics, metatranscriptomics, and metabolomics, has advanced our understanding of cyanobacterial dynamics, their metabolic potential, and symbiotic interactions with microbial consortia, as exemplified by the cyanosphere of Microcoleus vaginatus. In addition, recent advances in bioinformatics have enabled high-resolution taxonomic and functional profiling of environmental samples, facilitating the identification and prediction of resilient microorganisms suited to challenging degraded soils. These tools also allow for the prediction of biosynthetic gene clusters and the detection of prophages or cyanophages within microbiomes, offering a novel approach to enhance carbon sequestration in dry and nutrient-poor soils. This review synthesizes the latest findings and proposes a roadmap for the translation of molecular-level knowledge into scalable biotechnological strategies for soil restoration. We discuss approaches ranging from the use of native biocrust strains to the exploration of cyanophages with the potential to enhance cyanobacterial photosynthetic activity. By bridging ecological functions with cutting-edge omics technologies, this study highlights the critical role of cyanobacteria as a nature-based solution for climate-smart soil management in degraded and arid ecosystems. Full article

Forests play a key role in carbon sequestration and oxygen production. They significantly contribute to carbon peaking and carbon neutrality goals. Accurate estimation of forest carbon stocks is essential for a precise understanding of the carbon sequestration capacity of forest ecosystems. Remote sensing technology, with its wide observational coverage, strong timeliness, and low cost, is essential for carbon stock estimation research. However, challenges in data acquisition and processing include data variability, signal saturation in dense forests, and environmental limitations. These factors hinder accurate carbon stock estimation. This review summarizes the current state of research on forest carbon stock estimation from two aspects, namely remote sensing data and estimation methods, highlighting both the advantages and the limitations of various data sources and models. It also explores technological innovations and cutting-edge research in the field, focusing on deep learning techniques, optical vegetation thickness estimation methods, and the impact of forest–climate interactions on carbon stock estimation. Finally, the review discusses the current challenges in the field, including issues related to remote sensing data quality, model adaptability, forest stand complexity, and uncertainties in the estimation process. Based on these challenges, the paper looks ahead to future trends, proposing potential technological breakthroughs and pathways. The aim of this study is to provide theoretical support and methodological guidance for researchers in related fields. Full article

The urgent need for sustainable strategies to mitigate climate change has spurred the development of efficient carbon sequestration methods with minimal greenhouse gas emissions, presenting promising opportunities to produce biochar and, with this bioproduct, enhance crop productivity. Therefore, this research aimed to evaluate the carbon footprint produced by the low-temperature slow pyrolysis of biomass obtained from the pruning residues of four tree species present in parks and gardens of the southern Andean region of Ecuador. An electric reactor (ER), powered by 44 solar panels of 535 W each, was used to perform the pyrolysis process at 350 °C over four hours. For each species—Persea americana, Polylepis spp., Acacia spp., and Prunus salicifolia—three replicates of the process were conducted using 1.5 kg of biomass per trial. The results showed that Acacia spp. residues produced biochar with higher bulk density (0.303 g/cm³), organic matter (82.85%), total organic carbon (71.21%), oxygen (27.84%), C/N ratio (120.69), and potassium (459.12 ppm). The biochar produced from Prunus salicifolia exhibited the highest levels of pollutant gas emissions and carbon footprint (5.93 × 10⁻⁶ ton∙m⁻³ CO₂ eq and 0.001067 ton∙m⁻³ CO₂ eq, respectively). In contrast, the biochar produced from Polylepis spp. was the least polluting (0.001018 ton∙m⁻³ CO₂ eq), highlighting its potential as a source for biochar production from tree species found in the southern Andean region of Ecuador. Meanwhile, the pyrolysis of Persea americana (avocado) resulted in very low gas emissions, although it exhibited the second-highest carbon footprint due to the high energy consumption associated with the process. In conclusion, this study identified Persea americana and Polylepis spp. as the best options for biochar production through pyrolysis, positioning them as viable alternatives for developing sustainable strategies to mitigate climate change. Full article

Wetlands are one of the most crucial ecosystems for regulating carbon sequestration and mitigating global climate change. However, the disturbance to carbon dynamics caused by microplastics (MPs) in wetlands cannot be overlooked. This review explores the impacts of MPs on the carbon cycles within wetland ecosystems, focusing on the underlying physicochemical and microbial mechanisms. The accumulation of MPs in wetland sediments can severely destabilize plant root functions, disrupting water, nutrient, and oxygen transport, thereby reducing plant biomass development. Although MPs may temporarily enhance carbon storage, they ultimately accelerate the mineralization of organic carbon, leading to increased atmospheric carbon dioxide emissions and undermining long-term carbon sequestration. A critical aspect of this process involves shifts in microbial community structures driven by selective microbial colonization on MPs, which affect organic carbon decomposition and methane production, thus posing a threat to greenhouse gas emissions. Notably, dissolved organic matter derived from biodegradable MPs can promote the photoaging of coexisting MPs, enhancing the release of harmful substances from aged MPs and further impacting microbial-associated carbon dynamics due to disrupted metabolic activity. Therefore, it is imperative to deepen our understanding of the adverse effects and mechanisms of MPs on wetland health and carbon cycles. Future strategies should incorporate microbial regulation and ecological engineering techniques to develop effective methodologies aimed at maintaining the sustainable carbon sequestration capacity of wetlands affected by MP contamination. Full article

Water pollution from industrial, municipal, and agricultural sources is a pressing global concern, necessitating the development of sustainable and efficient treatment solutions. Algal biomass has emerged as a promising feedstock for the production of carbonaceous adsorbents due to its rapid growth, high photosynthetic efficiency, and ability to thrive in wastewater. This review examines the conversion of algal biomass into biochar and hydrochar through pyrolysis and hydrothermal processes, respectively, and evaluates their potential applications in wastewater treatment, carbon sequestration, and biofuel production. Pyrolyzed algal biochars typically exhibit a moderate to high carbon content and a porous structure but require activation treatments (e.g., KOH or ZnCl₂) to enhance their surface area and adsorption capabilities. Hydrothermal carbonization, conducted at lower temperatures (180–260 °C), produces hydrochars rich in oxygenated functional groups with enhanced cation exchange capacities, making them effective for pollutant removal. Algal-derived biochars and hydrochars have been successfully applied for the adsorption of heavy metals, dyes, and pharmaceutical contaminants, with adsorption capacities significantly increasing through post-treatment modifications. Beyond wastewater treatment, algal biochars serve as effective carbon sequestration materials due to their stable structure and high carbon retention. Their application as soil amendments enhances long-term carbon storage and improves soil fertility. Additionally, algal biomass plays a key role in biofuel production, particularly for biodiesel synthesis, where microalgae’s high lipid content facilitates bio-oil generation. Hydrochars, with energy values in the range of 20–26 MJ/kg, are viable solid fuels for combustion and co-firing, supporting renewable energy generation. Furthermore, the integration of these materials into bioenergy systems allows for waste valorization, pollution control, and energy recovery, contributing to a sustainable circular economy. This review provides a comprehensive analysis of algal-derived biochars and hydrochars, emphasizing their physicochemical properties, adsorption performance, and post-treatment modifications. It explores their feasibility for large-scale wastewater remediation, carbon capture, and bioenergy applications, addressing current challenges and future research directions. By advancing the understanding of algal biomass as a multifunctional resource, this study highlights its potential for environmental sustainability and energy innovation. Full article