Coastal salt marshes are critical blue carbon ecosystems, yet the regulatory pathways of vegetation succession on soil organic carbon (SOC) accumulation mediated by microbial carbon cycling gene abundances constitute a knowledge gap. This study investigated the trends of soil properties and microbial carbon cycling gene abundances among bare flat (BF), Scirpus mariqueter (SM), Spartina alterniflora (SA), and Phragmites australis (PA) communities at Southern Hangzhou Bay, Eastern China. Vegetation succession distinctly shaped soil properties and carbon cycling gene abundances (p < 0.05). Specifically, the 8-year invasion of SA increased the contents of SOC and its labile fractions, total nitrogen (TN), alkali-hydrolyzable nitrogen, texture parameters (clay and silt), amylase and invertase activity, contrasting with the effects of the 2-year invasion of SA (p < 0.05). The PA community exhibited superior carbon sequestration potential, characterized by enriched carbon degradation, carbon fixation, and methane metabolism gene abundances. Simultaneously, SA8 suppressed recalcitrant carbon metabolism but enhanced methanogenesis gene abundances. The abundances of carbon degradation, carbon fixation, and methane metabolism genes were significantly positively correlated with SOC, dissolved organic carbon, TN, ammonium, and nitrate nitrogen (p < 0.05). In contrast, the abundances of carbon degradation and carbon fixation genes were significantly negatively correlated with EC (p < 0.05). Vegetation succession from BF to PA in coastal wetlands reduced soil EC and improved soil texture, thereby further increasing TN content, increasing carbon cycling gene abundances, and ultimately promoting SOC accumulation. This study provides a mechanistic basis for predicting blue carbon sequestration under plant invasion or restoration scenarios.
In the context of escalating global climate change and China's commitment to its dual carbon goals, this study investigates the spatiotemporal dynamics of carbon balance across 296 prefecture-level and higher cities in mainland China from 2001 to 2022, using emission data from the EDGAR database. By integrating ecosystem carbon sequestration models with economic contribution coefficients (ECC), ecological support coefficients (ESC), and China's main functional zoning framework, we systematically analyze regional carbon sources and sinks and propose a spatially explicit optimization strategy. Results reveal a distinct "higher in the north than in the south, higher in the east than in the west" emission pattern, driven by economic agglomeration and energy structure, with industrial clusters such as Beijing-Tianjin-Hebei and the Yangtze River Delta acting as high-emission hotspots; notably, the Chengdu-Chongqing region exhibited a sharp emissions surge in 2022 due to accelerated industrialization. In contrast, carbon sequestration capacity forms a "northeast-southwest high axis," enhanced by ecological restoration in regions like the Yellow River Basin but diminished along the eastern coast due to urban expansion, thereby exacerbating regional carbon imbalance. Based on ECC and ESC, we classify areas into four dynamically adjusted carbon balance zones: (1) low-carbon maintenance zones (e.g., Beijing-Tianjin-Hebei, Chengdu-Chongqing), characterized by strong economic output and carbon sink potential; (2) economic development zones (e.g., Central Plains, Shandong Peninsula), reliant on high-carbon industries yet underpinned by relatively sound ecological foundations; (3) carbon sink development zones (middle reaches of the Yangtze River), combining significant economic contributions with fragile ecosystems; and (4) comprehensive optimization zones (e.g., Hohhot-Baotou-Ordos-Yulin, Hexi Corridor), facing dual economic and ecological pressures. These are further refined into 16 sub-zones aligned with national functional zoning to enable targeted policy implementation. We recommend zone-specific strategies: consolidating low-carbon technologies and ecological advantages in maintenance zones; accelerating industrial decarbonization and energy efficiency in development zones; strengthening ecological restoration and green industry cultivation in sink zones; and fostering coordinated socio-ecological development in optimization zones through policy incentives, interregional collaboration, and market mechanisms. Ultimately, achieving nationwide carbon balance hinges on two core pathways: optimized land-use planning and the implementation of differentiated, spatially tailored policies that account for local socioeconomic and ecological contexts.
Biomass-derived carbons hold great potential as multifunctional electrode materials for applications in energy storage and conversion. Herein, we reveal the self-compensation mechanism besides porosity nanoarchitectonics in carbons converted from high-carbon peat moss for high-performance electrode materials. Firstly, carbons are prepared from whole peat moss plant by lignin removal at room temperature and chemical activation at 700 °C, where the high cellulose content in leaf is disclosed to contribute to mesopore formation and the lignin-rich stem containing oriented channels results in macropore generation. Although the obtained carbon possesses a medium specific surface area of 651.0 m2 g-1, the hierarchical porosity provides ideal pathways for fast charge storage and transport, thereby demonstrating a high capacitance of 260.0F g-1 at 1 A g-1 as a supercapacitor electrode material. Alternatively, hydrothermal treatment of whole peat moss plant at 180 °C leads to its partial carbonization, accompanied with the formation of abundant carbon dots. Further pyrolysis of the obtained carbon intermediate at 950 °C improves its graphitization, but decreases the specific surface area to 419.8 m2 g-1 due to structural collapse. However, benefiting from the stem-leaf compensatory mechanism during hydrothermal carbonization, the incorporation of carbon dots endows the carbons with abundant active sites for oxygen reduction reaction (ORR), providing an onset potential at 0.94 V vs. RHE and a half-wave potential at 0.84 V vs. RHE in alkaline solution. A full-cell zinc-air battery device with the obtained carbons as the cathode catalyst delivers a high power density of 171 mW cm-2 and good durability.
Accelerating permafrost thaw may release vast deep (>3 meters) frozen soil carbon as carbon dioxide (CO2), but this magnitude remains uncertain because current Earth system models (ESMs) lack deep carbon processes. Using an updated ORCHIDEE-MICT model simulating Pleistocene Yedoma formation and Holocene peatland development, we project northern (>30°N) carbon responses under climate change. Compared to the original model, including these deep carbon pools improves agreement with observations and reduces net CO2 uptake by 47 to 74 petagrams of carbon from 1900 to 2100 across three future scenarios because of deep carbon decomposition with accelerated active-layer deepening. Under high-emission pathways, the northern soil carbon balance shifts from a sink to a source of 32 petagrams of carbon, advancing the reversal reported in earlier studies into the 21st century. Consistent with field data, our model shows that colder soils retain more labile carbon-contrary to assumptions in many Coupled Model Intercomparison Project (CMIP) models-helping explain their persistent sink bias. Our results highlight the need to represent both the quantity and quality of permafrost carbon in ESMs.
The linear carbon allotrope carbyne has been predicted to display outstanding electrical and mechanical properties, but its preparation and characterization are hindered by synthetic challenges. Although oligoyne and [n]cumulene models of carbyne have been explored, the end-groups used to avoid decomposition have a profound effect on their electronic configuration. Here we show that transmetallation of linear carbon fragments from Au(I) species to Au(0) electrodes delivers stable Au|CC…CC|Au devices. Scanning tunnelling microscope break junction techniques were used to characterize charge-transport behaviour in these one-dimensional carbon chains (up to 16 atoms) free of end-capping groups. Shorter chains exhibited oligoyne-like behaviour, with conductance attenuation as a function of length, whereas longer chains show evidence of bond-length equalization towards a cumulenic structure, with remarkably enhanced charge transport. The direct contact between the electrode and the carbon fragment at the Au|C interfaces grant high conductance and quasi-ballistic transport to one-dimensional carbon chains, providing a pathway to advanced carbon-based nanoelectronics based on the stabilization of carbyne within the junction environment.
Chitosan-based adsorbents have drawn considerable attention due to their effective removal of hazardous pollutants, such as heavy metal ions, microplastics, and organic pollutants, including phenols, dyes, fertilizers, pesticides, herbicides, and pharmaceuticals. However, the practical application of chitosan is limited by its relatively low adsorption capacity, poor mechanical properties, and susceptibility to dissolution in acidic solutions. Therefore, chitosan is commonly modified using different techniques, including chemical and physical approaches, or combined with other adsorbent materials to enhance its structural stability and adsorption properties. Chitosan has been integrated with various materials, including natural polymers (e.g., cellulose, chitin/chitosan, starch, alginate), clay minerals (e.g., perlite and montmorillonite), inorganic materials (e.g., zeolite, metal oxides, and metal-organic frameworks), and carbonaceous materials (e.g., graphene oxide, activated carbon, biochar, and carbon nanotubes). Among these, carbonaceous materials are promising materials, due to their high surface area, porosity, and stability, which significantly improve the mechanical properties, thermal stability, and electrical properties, as well as adsorption capacity. This review focuses on chitosan-based carbonaceous composite materials as adsorbents and covers several aspects, including their synthesis methods, structural and surface characteristics, mechanical properties, and adsorption performance as well as their applications in wastewater treatment, particularly for the removal heavy metals, dyes, organic pollutants (such as oil, fertilizers, antibiotics, and pharmaceuticals), nuclear wastes, and pathogenic microoganisms.
Pore size analysis is essential for understanding and optimizing structure-performance relations of functional carbon-based materials including activated carbons, supercapacitor electrodes and atomically dispersed metal-nitrogen-doped carbon (M-N-C) catalysts. Pore size distribution (PSD) plots based on gas sorption porosimetry often show narrow micropores that are related to the adsorptive properties of named materials, which must be considered as artefacts arising from approximations in classical density functional theory (cDFT) models. By selectively preparing specific in-plane functionalities using pyrolytic template-ion (salt templating) reactions, we herein show that those apparent pores can be explained by preferential adsorption of the adsorbate molecules to specific in-plane functionalities. Tetrapyrrolic Zn-N4 sites are present in ZIF-8 derived carbons, which are converted by Zn-extraction into nitrogen-doped carbons (NDC) comprising tetrapyrrolic H2N4 sites. DFT-based calculation of adsorption energies allows the conclusive assignment of corresponding adsorption phenomena in comparative N2 vs. CO2 vs. Ar adsorption measurements additionally using Langmuir analysis. While the assignment of artefacts may improve the discussion of porosity, the determination of specific adsorption sites may be utilized as a valuable tool in materials science. Advanced models for the important material classes may allow accelerated progress in important energy-related research fields.
Penguins are emblematic inhabitants of the Antarctic continent and play a significant role in the biogeochemical cycles of the Southern Ocean by transferring essential nutrients to marine ecosystems via guano production. Despite their ecological importance, the contribution of penguin guano to carbon cycling remains largely unexplored. Microplastics (MPs) add complexity to these dynamics. MPs in fecal material can limit carbon export by reducing sinking rates and increasing remineralization. We examined guano from two penguin species, the Chinstrap (P. antarcticus) (n = 25) and Gentoo (P. papua) (n = 7), from the South Shetland Islands. We quantified biogeochemical particulate components (carbon, nitrogen, and biogenic silica) and characterized MP polymeric composition. Both species showed similar values for natural particulate fractions. Microplastics were detected in 91% of samples, dominated by small particles (25-50 μm, 46%). Chinstrap guano contained the highest amount of MPs. Polypropylene was the predominant polymer (34% in Chinstrap, 75% in Gentoo), followed by polyethylene (37% in Chinstrap, not found in Gentoo). This study provides the first survey of the smallest MP fraction (down to 25 μm) in penguin guano, offering new insight into how a shift in the partitioning from natural to MP particles, previously overlooked, may influence guano-mediated carbon pathways.
The global rise in atmospheric CO2 concentration and its societal impact urges the development of sustainable carbon management via carbon capture, utilization, and storage (CCUS) strategies. Although CCUS addresses a challenge of global scale, the key processes occur at nanoscale interfaces among CO2, water, and solids, where reaction kinetics, thermodynamics, and transport determine CO2 fate and process performance, influencing the overall efficiency and sustainability of CCUS. Therefore, a better understanding and precise control of nanoscale interfacial chemistry in CCUS processes are vital. This review introduces the fundamental principles of CO2 interfacial reactions involved in CCUS, followed by a detailed examination of nanoscale interfacial processes in CO2 capture, utilization, and mineralization. We also explore the properties of various interfaces, the mechanisms governing nanoscale CO2 interactions, and their impacts on overall CCUS performance, highlighting how a deeper understanding and control of interfacial reactions can contribute to achieving net-zero CO2 emissions (NZE) targets. To support the characterization of these dynamic and complex interfacial processes, we discuss advanced characterization techniques for studying interfacial phenomena in carbon management systems. Finally, we suggest future research directions and opportunities in advancing carbon management by bridging nanoscale insights to field-scale applications of CCUS.
Perfluorooctanoic acid (PFOA), a persistent and bioaccumulative contaminant of emerging concern, poses substantial ecological risks to marine primary producers and can disrupt critical biogeochemical cycles. Marine diatoms are pivotal in coupling carbon (C) and silicon (Si) cycling and contribute substantially to oceanic C sequestration via the biological C pump. However, the mechanisms underlying PFOA-induced effects on diatom physiology and associated biogeochemical processes remain poorly understood. This study investigated the impacts of environmentally relevant (5 ng·L-1) and elevated (500 ng·L-1) PFOA concentrations on the model marine diatom Phaeodactylum tricornutum. PFOA exposure significantly altered dissolved silicon (DSi) dynamics, with DSi concentrations increasing by 5.95% and 21.96% at 5 and 500 ng·L-1, respectively. Biogenic silica (BSi) content increased by 9.66% at low PFOA but decreased by 1.01% at high PFOA. Dissolved organic carbon (DOC) decreased by 2.15% and 8.02%, while dissolved inorganic carbon (DIC) increased by 11.30% and 32.45% under low and high PFOA treatments, respectively. Transcriptomic analysis indicated that 500 ng·L-1 PFOA downregulated genes associated with C fixation while upregulating genes involved in the tricarboxylic acid (TCA) cycle. Additionally, expression of PHATRDRAFT_48708 was suppressed, whereas Si transporter 4 (SIT4) was upregulated, indicating dysregulation of Si homeostasis. These findings demonstrate that PFOA disrupts C-Si coupling at the cellular level in P. tricornutum, highlighting a potential mechanism by which PFOA may disrupt diatom-mediated C sequestration. Future validation using ecologically representative, heavily silicified diatom taxa is required to extrapolate these effects to natural oceanic C fluxes.
The magnitude of the terrestrial carbon sink remains a key uncertainty in future climate projections, in part due to poorly understood links between carbon uptake and its allocation to woody biomass in vegetation. Here, in this study, we show that photosynthesis and aboveground growth occur asynchronously across diel to seasonal scales in eight North American oak species. Across 137 tree ring sites, current-year annual growth was insensitive to climate variability after midsummer despite 26 to 36% of annual gross primary productivity (GPP) occurring during this period. Hourly GPP flux and growth measurements at four sites spanning seven site years further demonstrate that wood formation ceases earlier than photosynthesis and is restricted to periods of low atmospheric aridity and temperature. This photosynthesis-growth decoupling intensifies with interannual variability in vapor pressure deficit (r = 0.86, P < 0.05), suggesting that by assuming tight coupling between photosynthesis and woody biomass, current earth system models may overestimate long-term carbon sequestration in forests.
In this study, we report the synthesis and comprehensive characterization of heparin-capped carbon dots (Hep-C-dots) prepared using D-glucose as a carbon precursor and heparin, a negatively charged polysaccharide belonging to the glycosaminoglycan family, as a capping and stabilizing agent. The obtained Hep-C-dots exhibited a uniform nanoscale size distribution with an average diameter of 2.5 ± 0.5 nm and a high negative surface charge (- 36.8 mV). Full characterization of as-synthesized Hep-C-dots has been done by several state-of-the-art analytical techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and zeta potential analysis. The interactions between Hep-C-dots and key human proteins, namely human methemoglobin (HB) and human serum albumin (HSA), were investigated via fluorescence spectroscopy, demonstrating significant binding affinities with Ksv values of 2.61 ± 0.5 × 107 M- 1 for HSA and 1.83 ± 0.4 × 107 M- 1 for HB. Cytotoxicity assays performed on A549 lung cancer cells revealed that Hep-C-dots exhibit slightly higher toxicity compared to bare carbon dots (C-dots), with IC50 values of 176.21 µg/mL and 200.4 µg/mL, respectively. Moreover, hemolysis assessment using bovine red blood cells (RBCs) showed that Hep-C-dots induce negligible hemolysis (0.002% at 200 µg/mL), confirming their excellent hemocompatibility. These findings suggest that Hep-C-dots hold promise as biocompatible nanomaterials for biomedical applications.
In recent years, the application of gas injection, particularly carbon dioxide (CO2) dissolved in water, known as carbonated water (CW), has gained increasing attention. In this context, the current study is designed to examine the effect of CO2 dissolution in water under pressures ranging from 500 to 4500 psi, covering subcritical to supercritical conditions, and at temperatures between 25°C-65°C. Additionally, the synergistic effects of surfactants, namely dioctyl sulfosuccinate sodium salt (AOT) and sodium dodecyl polyoxyethylene ether sulfate (AES), were examined at concentrations ranging from 0 to 700 ppm, along with the dissolved CO2 on IFT and swelling factors. The measurements revealed that as the pressure increased, the swelling factor reached a maximum value of 19.3% when it was contacted with crude oil, while the maximum swelling factor for the solutions contacted with synthetic mixed resinous and asphaltenic oil (SMRAO) was reached at a value of 22.3%. The second oil type was selected as SMRAO since crude oil comprises thousands of components, making it hard to extract any generalized conclusions based on the obtained results. In this way, using only one or two specific fractions, especially resin and asphaltene which acts as natural surfactants, providing the chance to examine the generalized interactions between chemicals and oil fractions. The measurements revealed that the presence of surfactant in the carbonated water (CW) reduced the swelling factor up to 50% for AOT and 38% for AES as the pressure and temperature and surfactant concentration increases. The reason of this observed trend was correlated to the bulky structure of AOT compared with the linear chain-like structure of AES. Besides, the measurements revealed the positive impact of pressure and temperature on a higher swelling factor regardless of the used surfactants, which can be due to the higher dissolution of CO2 under higher pressures and better movement and migration of CO2 molecules, which means a penetration of higher amount of CO2 into the oil drop leading to higher swelling factors. In the next stage, the IFT of different solutions under different temperatures (25 °C-65 °C) and pressures (0-4500 psi) was measured. The obtained IFT values showed that using SMRAO instead of crude oil has a reducing impact on the IFT values with minimum value of 19.2 mN/m, while the IFT value for similar thermodynamic condition and crude oil was 23.1 mN/m. Besides, further IFT measurements revealed that although increasing pressure has a reducing impact on the IFT, increasing temperature increases the IFT values regardless of the presence of surfactant or even the type of surfactant. The measurements also revealed that the effect of AES on the IFT reduction was better than AOT, leading to a minimum IFT value of 1.1 mN/m for AES concentration of 700 ppm dissolved in CW with pressure and temperature of 4500 psi and 65 °C, respectively due to longer alkyl chain length and easier packing in the interface compared with AOT which has a bulky structure prevents the high number of AOT molecules to be packed in the interface. The measured IFT values revealed the linear IFT variation behavior for the systems were in contact with SMRAO compared with crude oil due to this fact that the SMRAO has less complexities than crude oil comprises of thousands of components makes the IFT variations more straightforward for SMRAO.
Delivery of health care is a substantial contributor of greenhouse gas emissions. The National Health Service (NHS) in England has been assessing emissions associated with its activities since 2008, and in 2020 was the first health care system worldwide to set net-zero emissions targets. This Article presents updated methodology used to calculate consistent estimates of NHS emissions between 2019-20 and 2024-25. A hybrid approach was used to estimate emissions associated with health-care activity funded by the NHS in England. NHS-specific activity and spend data were used when available. Resulting emission estimates were presented and compared with the previous estimate for 2019-20. The volume and emissions intensity data quality were also assessed and compared with the previous methodology. Insights from the emissions estimates, sources of remaining uncertainties, and the direction of future development are discussed. Total NHS emissions increased during the COVID-19 pandemic but have since returned to pre-pandemic levels and are estimated to be 27·3 megatonnes of carbon dioxide equivalent (MtCO2e) in 2024-25. Emissions under NHS direct control have decreased by 14% (0·8 MtCO2e) since 2019-20. Data quality scores have improved by nearly 30% compared with those of the previously used methodology. This Article represents the most sophisticated and granular footprinting of health care to date, adding to international evidence and supporting global efforts to decarbonise health care. Within England, improved estimates will support actionable insights at the national and local level, as well as improved monitoring of progress towards the NHS net-zero targets. None.
In order to guarantee the safety of food and quality control of drugs, it is crucial to develop a rapid, accurate and sensitive method for myricetin detection. In this study, vanadium-doped carbon dots (V-CDs) with peroxidase-like activity (POD) were synthesized through a one-step hydrothermal method. Based on the redox reaction between myricetin and the reactive oxygen species generated by V-CDs catalyzed H2O2, a colorimetric sensor was developed. This sensor featured high sensitivity, excellent selectivity and rapid detection capability, showing a good linear relationship within the range 1.0-50 µM, with a detection limit as low as 0.47 µM. Furthermore, using a smartphone a visual sensing platform was established and successfully realized monitoring of myricetin in samples. The proposed method avoids complex instrumentation and tedious sample pretreatment, making it highly suitable for on-site screening. This work not only presented a new type of carbon dots-nanozyme, but also provided an economical, user-friendly and detection method for myricetin.
Soils have been proposed as a tool to reduce atmospheric carbon dioxide (CO2). However, sparse field data and soil databases that do not account for geomorphic controls on soil properties hinder accurate quantification of soil organic carbon (SOC) dynamics at the watershed scale. In mountainous terrain, relict landslide deposits are common and feature thick (>5 m), weathered profiles with substantial SOC below the typically measured top 30 cm of soil. We generated a SOC-age relationship using a landslide chronosequence in Western Oregon where these landforms are abundant. We applied our relationships to an inventory of nearly 10,000 previously dated landslides and show that deep SOC stocks constitute ~70% of the total stock for landslides >41.8 thousand years. Our findings also show that SOC stocks associated with deep-seated landslides are >2× larger than estimates from a global model that does not account for geomorphic controls. These results suggest that geomorphology can improve our ability to quantify SOC stocks and could inform watershed management.
Evaluating soil organic carbon (SOC) and soil total nitrogen (STN) concentrations together with carbon and nitrogen stable isotope signatures across aggregate fractions can provide novel insights into the mechanisms underlying SOC and STN sequestration following afforestation. However, the impacts of different afforestation strategies on the distribution, transformation, and stabilization of SOC and STN among aggregate fractions, especially in degraded karst ecosystems, remain unclear. Here, aggregate size composition, SOC and STN concentrations, as well as δ13C and δ15N values in bulk soils and aggregate fractions were examined after 10 years of afforestation in a karst rocky desertification region. Eight treatments were selected, including five monoculture plantations (Pinus massoniana, Photinia glomerata, Pistacia weinmannifolia, Eucalyptus, and Fraxinus malacophylla), one mixed-species plantation dominated by F. malacophylla, P. massoniana, Rhus chinensis, Solanum deflexicarpum, and Campylotropis harmsii, as well as adjacent abandoned land and secondary forest as controls. Afforestation significantly increased SOC and STN storages relative to abandoned land, with larger gains under mixed-species afforestation (4.30 kg C m-2 and 0.29 kg N m-2) than under monocultures (1.09‒2.47 kg C m-2 and 0.08‒0.16 kg N m-2). Meanwhile, mixed-species afforestation significantly increased the >2 mm aggregates proportions, improved aggregate stability, and exhibited higher δ13C and δ15N values in both bulk soils and aggregate fractions compared to monoculture plantations. In afforested soils, δ13C and δ15N values increased with increasing aggregate size, while soil C flow pathways progressively shifted from <0.053 mm to 4-8 mm aggregates, leading to higher SOC and STN concentrations within >2 mm aggregates. The enhanced SOC and STN storages under mixed-species afforestation were primarily driven by the increased >2 mm aggregate proportions and their higher associated SOC and STN concentrations, with the former playing a greater role. These processes were strongly associated with improved litter and root quality, and higher soil calcium and magnesium oxides concentrations. However, even after 10 years of mixed-species afforestation, the proportion of >2 mm aggregates, aggregate stability, and SOC and STN storages remained significantly lower than those in the secondary forest. Our results demonstrate that mixed-species afforestation is more effective than monoculture plantations in enhancing soil structural stability and promoting SOC and STN sequestration, supporting its priority in vegetation restoration of degraded karst ecosystems.
The rapid expansion of the textile industry presents critical challenges in achieving sustainable consumption and production. In response, this study develops an integrated sustainable production model for the yarn sector. The proposed model incorporates investments in green technology and wastewater purification systems, assessing their influence on both economic performance and environmental sustainability. The average integrated total profit of the system is optimized, and the model's practicability is demonstrated through a numerical illustration. The findings reveal that upcycling old garments enhances overall profitability by an average of 5.13% under both carbon pricing policies. Furthermore, while the CCT mechanism reduces green investment costs by 3.18%, the CT policy achieves a 2.29% reduction, highlighting the superior emission mitigation efficiency of the CCT approach. The suggested model advances sustainable production-consumption in the yarn industry by repurposing banana waste for yarn, and adopting the extended producer responsibility (EPR) directive, all while maintaining system profitability.
Our objective was to estimate the effects of productivity gain, functional units (FU), quantification and allocation methods of greenhouse gas emission on milk carbon footprint (CF) in dual-purpose dairy production system in Bangladesh. An attributional cradle-to-farmgate life cycle assessment (LCA) was conducted following ISO-14040/14044 and FAO guidelines, including feed production, enteric emissions, manure management, and farm energy in system boundary. Foreground data including herd structure, milk yield and composition, diets, manure management, and farm energy from Bangladesh Agricultural University Dairy Farm (2018-2023) were used to build LCA model. Enteric methane (CH4), manure CH4, and nitrous oxide emissions were estimated using Intergovernmental Panel on Climate Change Tier-1 and Tier-2 methods. FU compared were 1 kg fat-and-protein corrected milk (FPCM), 100-kcal energy, and 100-g protein. Emissions were allocated between milk and meat using no allocation assumption, biophysical, or economic methods when FPCM was used as FU. Across 5 years, average CF was 5.18 ± 1.03 kg CO2-eq kg-1 FPCM under the no-allocation IPCC Tier 2 approach, and milk CF declined by 37% (6.89 to 4.34 kg CO2-eq kg-1 FPCM) as productivity increased by 63% (3.53 to 5.76 kg cow-1 d-1). Tier 2 method, using system-specific factors, had 27% lower CF than Tier 1. Productivity gain had similar reduction effects on CF when using 100-kcal energy or 100 g protein as FU. Biophysical and economic allocation reduced CF by 47% and 36%, respectively, compared with no allocation. Uncertainty analysis showed wide CF variation across years, and sensitivity analysis identified milk yield and herd structure as the most influential drivers. Enteric fermentation was the dominant emission source (48%), followed by feed (24%), manure (20%), and farm energy (8%). These findings highlight the importance of productivity improvement and methodological choices for shaping CF estimates and evaluating sustainable dairy production in low-input dual-purpose systems.
An understanding of carry-over effects in oviparous wildlife - and thus effective conservation - requires knowledge of how nutrients are allocated during egg production. Stable isotope analysis is commonly used to estimate the contribution of nutrients from body reserves (endogenous) versus those from diet (exogenous) to eggs. However, reliable inference about oviparous nutrient allocation strategies is dependent on isotopic discrimination factors, which are highly variable, species specific, and often based on data for a limited number of species. To determine carbon (δ13C) and nitrogen (δ15N) discrimination factors for birds' eggs, we conducted a feeding trial with captive killdeer (Charadrius vociferus) and measured δ13C and δ15N values in whole food, food constituents (protein and lipid-based), egg components (albumen, whole yolk, lipid-free yolk, and yolk lipid), and somatic tissues (pectoral muscle, subcutaneous fat) in females. We calculated diet and component specific discrimination factors and used Bayesian stable isotope mixing models to evaluate changes in nutrient allocation over the course of the egg-laying period. Our results show that discrimination factors in killdeer are distinct from those reported for other species and suggest seasonally variable endogenous nutrient inputs to protein-based egg components in this system. The first study to report these types of data for a shorebird, our findings provide new insights about the relationships between avian nutrition, reproduction, and potential carry-over effects.