Carbon Fractions Research Articles

Calcium forms influence soil organic carbon by mediating labile organic carbon fractions, carbon pool management indices and microbial communities in calcareous alkaline soils

Calcium forms influence soil organic carbon by mediating labile organic carbon fractions, carbon pool management indices and microbial communities in calcareous alkaline soils

Comparison of Q-Switched Nd:YAG LASER with 10% Azelaic Acid versus Fractional CO2 LASER with 10% Azelaic Acid in the treatment of Post Inflammatory Hyperpigmentation secondary to Acne

Background:Post inflammatory hyperpigmentation (PIH) secondary to acne is a common undesirable sequela following acne that leads to psychological distress and a sense of incomplete treatment among the patients with acne. Few studies have been done in regard to address this condition, and no definite treatment or clear ranking of treatment modalities is available as of yet.Aims:The aim of our study was to assess and compare the efficacy and safety of 1,064-nm Q-switched neodymium-doped yttrium aluminum garnet (QSNY) laser with 10% azelaic acid versus Fractional carbon dioxide (FCO2) laser with 10% azelaic acid in the treatment of post acne pigmentation.Materials and Methods:Seventy patients with PIH secondary to acne were recruited in this study. The patients were randomized into two groups, Group A and Group B, of thirty-five patients each. Patients in group A underwent QSNY laser, while Group B received FCO2 laser. 10% azelaic acid cream was administered to both groups. Both groups received a total of 5 treatment sessions, with 3 weeks interval between each setting. The efficacy and safety of both modalities were assessed using the quartile grading score(QGS), post acne hyperpigmentationindex(PAHPI), patient satisfaction score, and documentation of adverse effects.Results:At the end of five sessions, significant improvement in QGS, PAHPI and patient satisfaction (P < 0.001, respectively) was seen in both groups. The mean PAHPI significantly reduced after the third setting and was followed by drastic reduction in the following settings. However, significantly superior results were noted in Group A with respect to all assessments. Side effects noted were mild and transient, except two patients of Group B who developed further pigmentation over the treatment areas.Conclusion:This study shows that both QSNY laser and FCO2 laser can be used to treat post-acne pigmentation; however, QSNY laser should be preferred with respect to efficacy and safety, especially in the Indian population, owing to the higher risk of pigmentation following FCO2 laser.

Enhancing soil organic carbon prediction of LUCAS soil database using deep learning and deep feature selection

The main terrestrial carbon (C) fraction is soil organic carbon (SOC), which has a considerable effect on climate change and greenhouse gas emissions through the absorption and sequestration of carbon dioxide (CO2). This has made SOC assessment very important from both economic and environmental viewpoints. The growing count of soil spectral libraries (SSLs) from regional to global scales has brought a tremendous opportunity for the quantification of SOC through developing spectral-based prediction models. Hence, there is a need to take advantage of big data analytics for spectral data processing. The unique ability of deep learning (DL) techniques to leverage important features of high-dimensional large-scale SSLs has made them top-demanding for more sophisticated modeling. The core objective of the present study was to assess the ability of two different DL algorithms, i.e., one-dimensional convolutional neural network (1DCNN) and fully connected neural network (FCNN) coupled with stacked autoencoder (SAE) feature extraction for SOC prediction based on the data from the land use/cover area frame statistical survey (LUCAS) database. SAE extracted the high-level deep features from the visible–near-infrared–shortwave infrared (Vis–NIR–SWIR) spectra of 11441 soil samples, which were then considered as inputs to the 1DCNN and FCNN models for predicting the SOC content. Both SAE-DL feature-selected models yielded higher accuracy than those the DL developed on the entire spectra and a random forest (RF) model was constructed for comparison. The best prediction was achieved by SAE-1DCNN (R2= 0.78, RMSE = 3.94%, RPD = 4.88, RPIQ = 3.91) followed by 1DCNN (R2= 0.73, RMSE = 5.43%, RPD = 3.67, RPIQ = 2.84) proving the superiority of 1DCNN over FCNN in this study. These results supported the applicability of combined deep features extraction and regression methods for predicting SOC using high dimensional large-scale SSLs.

Effect of iron-based nanomaterials on organic carbon dynamics and greenhouse gas emissions during composting process

Iron-based nanomaterials as effective additives can enhance the quality and safety of compost. However, their influence on organic carbon fractions changes and greenhouse gas emissions during composting remains unclear. This study demonstrated that iron-based nanomaterials facilitate the conversion of light organic carbon fraction into heavy organic carbon fraction, with the iron-based nanomaterials group showing a significantly higher heavy organic carbon fraction content (41.88%) compared to the control group (35.71%). This shift led to an increase in humic substance content (77.5 g/kg) and a reduction in greenhouse gas emissions, with CO2, CH4, and N2O emissions decreasing by 20.5%, 39.7%, and 55.4%, respectively. Additionally, CO2-equivalent emissions were reduced by 42.9%. Microbial analysis revealed that iron-based nanomaterials increased the abundance of Bacillus and reduced the abundance of methane-producing archaea such as Methanothermobacter and Methanomassiliicoccus. These results indicated that the role of iron-based nanomaterials in regulating reactive oxygen species production and specific microbial communities involved in humification process. This study provides a practical strategy for improving waste utilization efficiency and mitigating climate change.

Mechanistic insights into the co-transport of microplastic degradation products in saturated porous media: The key role of microplastics-derived DOM

Microplastic-derived dissolved organic matter (MP-DOM) forms from the aging of microplastics (MPs), but the co-transport behavior of MP-DOM and aged MPs (AMPs) remains poorly understood. This study investigates the co-transport of AMPs and MP-DOM generated from original MPs (OMPs) over a wide range of environmentally relevant conditions. The transport of AMPs and MP-DOM changes as the degree of aging increases, specifically related to changes in their physicochemical characteristics. Results showed that the order of migration ability was MP-DOM > AMPs > OMPs under almost all tested conditions. The change of hydrophobicity of MP-DOM and AMPs, as well as small molecular weight of MP-DOM, was primarily responsible for this order. The role of MP-DOM as a degradation product in the co-transport process is notably significant under various environmental conditions because of its high mobility and organic carbon fraction within the system. Furthermore, it is important to note that MP-DOM affected the transport of MPs through a combination of positive and negative effects. Key mechanisms include electrostatic repulsion caused by protonation reactions triggered by the acidic pH of MP-DOM, steric hindrance, and competition for retention sites on media surfaces. This study contributes to a deeper understanding of the transformation and fate of MPs in complex environmental systems.

Radiocarbon age-offset measurements reveal shifts in the transport mechanism and age of permafrost-derived organic carbon from Burial Lake, arctic Alaska from MIS 3 to present

The stability of arctic permafrost and the carbon it contains are currently threatened by a rapidly warming climate. Burial Lake, situated in northwestern arctic Alaska, is underlain by continuous permafrost and has a uniquely rich set of paleoclimate proxy data that comprise a 40-ka record of climate and environmental change extending well into Marine Isotope Stage (MIS) 3. Here, we examine the relationship between erosion, subsurface hydrology, and primary productivity from the Burial Lake sediments to improve our understanding of the links between climate, hydrology, sediment transport, and carbon mobility. The record is developed with radiocarbon (14C) age-offsets from two independent methods used to date the lake sediments: 1) 14C measurements on paired bulk sediment and plant macrofossils from the same stratigraphic layer of lake sediment and 2) ramped pyrolysis-oxidation (RPO) 14C analysis that separates fractions of organic carbon (OC) from a single bulk sediment sample based on thermochemical differences through continuous heating. As lakes capture and archive OC transported from the watershed, changes in the amount and relative age of permafrost-derived OC mobilized during past climatic variations can be documented by examining how age-offsets change over time. The Burial Lake sediment revealed higher age-offsets during the cold Last Glacial Maximum (LGM; ∼29-17 ka) than the comparatively warmer post-glacial (∼17 ka-present) and the MIS 3 interstadial (∼40-29 ka) periods. The relatively warm, wet climate of the post-glacial period promoted both terrestrial and aquatic productivity, resulting in increased OC deposition, and it likely favored transport via subsurface flow of dissolved OC (DOC) sourced from soils. This resulted in a greater flux of contemporary OC relative to ancient OC into the lake sediment, lowering the average age offset to ∼2 ka. In contrast, the low-productivity conditions of the LGM resulted in slow soil accumulation rates, leaving ancient OC in a shallower position in the soil profile and allowing it to be easily eroded in the form of particulate OC (POC). Although the amount of total OC deposited in the lakebed during the LGM is small relative to post-glacial deposition, the majority is ancient, which leads to a relatively high average age offset of ∼9 ka. Finally, climate and environmental conditions of the MIS 3 interstadial were intermediate between those of the post-glacial and the LGM. As with post-glacial sediments, a relatively large amount of OC is present; however, the vast majority of it is ancient (more similar to the LGM), and it produces an average age offset of ∼6 ka. The Burial Lake radiocarbon record demonstrates the complexities of the thaw and mobilization of permafrost OC in arctic Alaska, including the balance between production, transport, deposition, remobilization, and preservation. This record highlights the importance of considering factors that both enhance and inhibit erosion (i.e. vegetation cover, lake level, precipitation) and the mechanisms of OC transport (i.e. subsurface flow or erosion) in predictions of future permafrost response to changes in climate.

Effects of land use systems on total organic carbon and carbon in the oxidizable fractions of soil organic matter

Effects of land use systems on total organic carbon and carbon in the oxidizable fractions of soil organic matter

Biomass valorization: Comparative analysis of tea waste pellets and wood pellets for steam generation and emission profiles

This study investigates the viability of tea waste as a biomass feedstock for pellet production and its combustion characteristics. Tea waste, an abundant agricultural byproduct, presents a promising avenue for renewable energy generation if effectively utilized. The pellets derived from tea waste were subjected to detailed analysis focusing on their calorific values and carbon composition. The calorific value of tea waste pellets was determined to be approximately 18.5 MJ/kg, comparable to conventional wood pellets. Notably, these pellets exhibit a high carbon content of 45 %, indicating a significant fixed carbon fraction that necessitates tailored combustion strategies for optimal efficiency. This research underscores the potential of tea waste pellets as a sustainable biofuel, contingent upon the development and application of precise combustion methodologies. It underscores the critical importance of understanding the chemical properties of solid biofuels in optimizing their utilization for energy production.

Arbuscular mycorrhizal fungi regulation of soil carbon fractions in coal mining restoration: Dominance of glomalin-related soil proteins revealed by stable carbon isotopes (δ13C)

Arbuscular mycorrhizal fungi (AMF) play a pivotal role in soil carbon cycling by orchestrating the recruitment of microbial communities and establishing hyphal networks. Understanding whether these attributes of AMF are instrumental in restoring soil carbon pools in areas disrupted by coal mining is crucial for forecasting soil organic carbon (SOC) dynamics in post-disturbance restoration sites. This study conducted a year-long, in-situ leaf decomposition experiment (comprising three shrubs: Amorpha fruticose, Caragana, and Sea buckthorn; two treatments: inoculated with AMF and without AMF inoculation) at the mycorrhizal restoration demonstration base in Inner Mongolia's mining area. Utilizing stable isotope technology, we investigated the mycorrhizal regulatory effects on aggregate carbon dynamics during the leaf decomposition process. Our findings showed that the presence of AMF hyphae accelerated carbon transformation within aggregates, resulting in augmented content of mineral-bound carbon (+6.1 %) and δ13C abundance (7.1 %) within microaggregates in sea buckthorn plots. Analysis employing random forest and partial least squares regression models corroborated that the regulation of mycorrhizal dynamics on aggregate carbon composition after fresh leaf input was indirectly influenced by GRSP rather than directly by AMF hyphae. In summary, our findings elucidate the evolving patterns of aggregate carbon dynamics following AMF inoculation in coal mining reclamation sites under field conditions. This underscored the efficacy of planting sea buckthorn and inoculating AMF during the vegetation restoration process of open-pit mine reclamation land in Inner Mongolia.

An assessment of Rare Earth Elements in borehole cores from the Ermelo, Witbank and Waterberg Coalfields, South Africa: Focus on mode of occurrence

There is currently limited knowledge concerning South African coal deposits as hosts for rare earth elements (REE). This project aims to determine the concentration of REE, including yttrium and scandium (REY+Sc) in various coal seams and adjacent sediments in borehole cores from the Ermelo, Witbank, and Waterberg coalfields in South Africa. Coal petrography (maceral count and vitrinite reflectance), XRD, XRF, sequential chemical extraction procedure (SCEP) before ICP-MS, and mineral liberation analysis (MLA) were conducted on the coal and associated sediment samples. The coals were inertinite-rich, medium-rank bituminous coal, with moderate to high ash content. The two dominant minerals in all the coalfields are kaolinite and quartz, except for sample ZBS2M, where dolomite was dominant. The dominant major oxides are Al2O3, SiO2, Fe2O3, and CaO, which concur with the XRD results. The ICP-MS results following SCEP indicated that both coal and the associated sediments were light REY+Sc dominant. There was also an elevation of medium REY+Sc in the Witbank coal's associated sediment samples. Notably, the samples with the highest REY+Sc results were the sediment samples. The Waterberg samples had the lowest REY+Sc from both the coal (less than 2 μg/g to 7 μg/g) and associated sediments (2 μg/g to 15 μg/g). While the highest REY+Sc was yielded from the Witbank-associated sediments (500 μg/g to 2,500 μg/g). The carbonate fraction step proved to be the most successful leaching step, as most REY+Sc was recovered in that step for all coalfields. In addition to the carbonate fraction, the silicates and sulfide fraction in the Witbank samples, and the ion-exchangeable fraction for the Waterberg-associated sediments samples proved successful in leaching out the REY+Sc. MLA determined that monazite and xenotime in all the coal samples were the REY+Sc-bearing minerals.

Battle of the CH motions: aliphatic versus aromatic contributions to astronomical PAH emission and exploration of the aliphatic, aromatic, and ethynyl CH stretches.

Strong anharmonic coupling between vibrational states in polycyclic aromatic hydrocarbons (PAH) produces highly mixed vibrational transitions that challenge the current understanding of the nature of the astronomical mid-infrared PAH emission bands. Traditionally, PAH emission bands have been characterized as either aromatic or aliphatic, and this assignment is used to determine the fraction of aliphatic carbon in astronomical sources. In reality, each of the transitions previously utilized for such an attribution is highly mixed with contributions from both aliphatic and aromatic CH motions as well as non-CH motions such as CC stretches. High-resolution gas-phase IR absorption measurements of the spectra of the aromatic molecules indene and 2-ethynyltoluene at the Canadian Light Source combined with high-level anharmonic quantum chemical computations reveal the complex nature of these transitions, implying that the use of these features as a marker for the aliphatic fraction in astronomical sources is not uniquely true or actually predictive. Further, the presence of aliphatic, aromatic, and ethynyl CH groups in 2-ethynyltoluene provides an internally consistent opportunity to simultaneously study the spectroscopy of all three astronomically important groups. Finally, this study makes an explicit connection between fundamental quantum mechanical principles and macroscopic astronomical chemical physics, an important link necessary to untangle the lifecycle of stellar and planetary systems.

Variation in microbial communities and network ecological clusters driven by soil organic carbon in an inshore saline soil amended with hydrochar in Yellow River Delta, China

Char materials (e.g., hydrochar) can enhance carbon sequestration, improve soil quality and modulate soil microbial communities to recuperate soil health. However, little is known about the soil organic carbon (SOC) content, as well as the microbial communities and co-occurrence networks in response to hydrochar amendment in an inshore saline soil. Here, the effect of Sesbania cannabina (a halophyte) straw derived hydrochar (SHC) amendment on SOC and labile organic carbon (LOC) fractions and the potential associations among SOC content change, soil C-cycling enzyme activities and microbial communities were illustrated using a pot experiment. SHC effectively improved the contents of SOC and LOC, particularly particulate organic carbon (POC), and stimulated the activities of C-cycling enzymes. Furthermore, SHC induced shift in microbial community compositions and co-occurrence networks, result in decrease in relative abundance of Actinobacteriota and its corresponding ecological cluster, which may favor SOC accumulation. Functional annotation of prokaryotic taxa (FAPROTAX) analysis also revealed a decrease in microbial ecological function related to carbon degradation. These findings provided a deeper insight about the hydrochar-induced SOC enhancement and suggested an efficient approach to improve C sequestration and improve soil health in the coastal salt-affected soil.

Investigating the complementarity of thermal and physical soil organic carbon fractions

Abstract. Partitioning soil organic carbon (SOC) in fractions with different biogeochemical stability is useful to better understand and predict SOC dynamics and provide information related to soil health. Multiple SOC partition schemes exist, but few of them can be implemented on large sample sets and therefore be considered relevant options for soil monitoring. The well-established particulate organic carbon (POC) vs. mineral-associated organic carbon (MAOC) physical fractionation scheme is one of them. Introduced more recently, Rock-Eval® thermal analysis coupled with the PARTYSOC machine learning model can also fractionate SOC into active (Ca) and stable SOC (Cs). A debate is emerging as to which of these methods should be recommended for soil monitoring. To investigate the complementarity or redundancy of these two fractionation schemes, we compared the quantity and environmental drivers of SOC fractions obtained on an unprecedented dataset from mainland France. About 2000 topsoil samples were recovered all over the country, presenting contrasting land cover and pedoclimatic characteristics, and analysed. We found that the environmental drivers of the fractions were clearly different, the more stable MAOC and Cs fractions being mainly driven by soil characteristics, whereas land cover and climate had a greater influence on more labile POC and Ca fractions. The stable and labile SOC fractions provided by the two methods strongly differed in quantity (MAOC/Cs=1.88 ± 0.46 and POC/Ca=0.36 ± 0.17; n=843) and drivers, suggesting that they correspond to fractions with different biogeochemical stability. We argue that, at this stage, both methods can be seen as complementary and potentially relevant for soil monitoring. As future developments, we recommend comparing how they relate to indicators of soil health such as nutrient availability or soil structural stability and how their measurements can improve the accuracy of SOC dynamics models.

Label-Free Quantitative Phosphoproteomics in the Fission Yeast Schizosaccharomyces pombe.

Protein phosphorylation is a dynamic, reversible posttranslational modification that plays an important role in the regulation of cell signaling. Recently, label-free quantitative (LFQ) phosphoproteomics has become a powerful tool to analyze the phosphorylation of proteins within complex samples. In this chapter, we describe how to apply LFQ phosphoproteomics that is based on Fe-IMAC phosphopeptide enrichment followed by strong anion exchange (SAX) and porous graphitic carbon (PGC) fractionation strategies for identification and quantification of changes in the phosphoproteome in the fission yeast Schizosaccharomyces pombe.

Novel long pulse potassium-titanyl-phosphate with substructured pulses – An effective tool in treating post-inflammatory erythema: A report of two cases in darker skin

The utilization of lasers is advancing as the range of applications for laser therapy expands, and new devices have been introduced. Vascular coagulation, pigment ablation, skin regeneration, tissue cutting or ablation, and hair removal are the five primary applications of laser therapy for the treatment of dermatological conditions. We present two cases of female patients with bilateral facial redness, one due to electromedical plasmage and the other from fractional carbon dioxide (CO2) laser, in which the target of their therapy was to improve acne scarring. Facial redness in both cases was successfully treated using a potassium-titanyl-phosphate (KTP) laser with cryogen cooling. The KTP laser has demonstrated efficacy in treating erythema associated with various conditions, including CO2 fractional laser and plasmage therapy. One of the advantages of the KTP laser is that it minimizes post-operative purpura and erythema, making it a favorable option for treating erythema itself.

Edge Influence in a Semi‐Deciduous Tropical Forest: An Investigation of Soil Organic Carbon Fractions

ABSTRACTRecent studies have proven the sensitivity of soil organic carbon (SOC) in responding to variations imposed by tropical forest fragmentation, which may reflect changes in both its quantity and quality. Despite this, studies evaluating soil carbon fractions as an edge effect indicator are still non‐existent. We developed this work asking: How do the oxidizable fractions of soil organic carbon (OFSOC) respond to the edge effect in fragments of semi‐deciduous seasonal forest? Is this response influenced by the size of the forest fragment? The study was conducted in Vitória da Conquista, Bahia, Brazil, in three forest fragments with different sizes. Thus, three sampling sections were defined in each fragment: edge (0–10 m), transition (40–50 m), and interior. Soil samples were collected at a depth of 0–10 cm. The SOC was divided into three fractions (LC—labile carbon, MLC—moderately labile carbon, and LLC—low labile carbon), adopting the chemical method based on oxidation degrees. Reductions in the SOC (28.2%), LC (17.4%), and MLC content (66.7%) were observed at the edge in the small fragment. There was a reduction of SOC (21.3%) and LLC (39.0%) at the edge in the medium fragment, while MLC showed an increase at the edge (70.4%). The OFSOC were able to respond to the changes imposed by the edge effect, with emphasis on the LC and MLC fractions in smaller fragments. The forest fragment size influenced the level of changes caused by the edge effect in OFSOC, showing greater susceptibility in smaller fragments.

Efficacy and safety of sequential treatment with botulinum toxin type A, fractional CO2 laser, and topical growth factor for hypertrophic scar management: a retrospective analysis

Hypertrophic scars arise from aberrant wound healing and can lead to functional and aesthetic impairments. One of the common interventions for treating hypertrophic scars is fractional carbon dioxide (CO2) laser, which employs narrow laser beams to stimulate dermal collagen deposition. Recent studies and reports have suggested that combining laser therapy with other interventions such as botulinum toxin type A (BTX-A) and topical growth factors may enhance treatment outcomes. Here, we examine the efficacy and safety of a sequential combination of BTX-A, fractional CO2 laser, and topical growth factors, referred to as combined therapy, for treating hypertrophic scars compared with only using fractional CO2 laser and topical growth factors, referred to as monotherapy. Our retrospective study includes 128 patients with hypertrophic scars (56 underwent monotherapy and 72 underwent combined therapy), which were followed-up for up to 15 months after the initiation of treatment to collect demographic and clinical data. Our analysis showed that the combined therapy significantly outperformed monotherapy in improving Vancouver scar scale scores (P < 0.05) and in the reduction of scar thickness (P < 0.05), without increasing adverse complications. Repeated treatments further augmented the efficacy of the combined therapy. Subgroup analysis revealed that combined therapy was notably more effective in reducing Vancouver scar scale scores and scar thickness in early-stage scars compared to late-stage (P = 0.023 and P = 0.045, respectively). Our study suggests that including BTX-A treatment before fractional CO2 laser and topical growth factors offers superior efficacy in reducing hypertrophic scars. We encourage early intervention and repeated treatments for optimal treatment outcomes.

The Fungal Community Structure Regulates Elevational Variations in Soil Organic Carbon Fractions in a Wugong Mountain Meadow.

Soil organic carbon (SOC) fractions are vital intrinsic indicators of SOC stability, and soil fungi are the key drivers of soil carbon cycling. However, variations in SOC fractions along an elevational gradient in mountain meadows and the role of the fungal community in regulating these variations are largely unknown, especially in subtropical areas. In this study, an elevation gradient experiment (with experimental sites at 1500, 1700, and 1900 m) was set up in a Miscanthus sinensis community in a meadow on Wugong Mountain, Southeast China, to clarify the effects of elevation on soil fungal community composition, microbial residue carbon, and SOC fractions. The results showed that the contribution of soil microbial residue carbon to SOC was only 16.1%, and the contribution of soil fungal residue carbon to SOC (15.3%) was far greater than that of bacterial residue carbon (0.3%). An increase in elevation changed the fungal community structure and diversity, especially in the topsoil (0-20 cm depth) compared with that in the subsoil (20-40 cm depth), but did not affect fungal residue carbon in the two soil layers. When separating SOC into the fractions mineral-associated organic carbon (MAOC) and particulate organic carbon (POC), we found that the contribution of MAOC (66.6%) to SOC was significantly higher than that of POC (20.6%). Although an increased elevation did not affect the SOC concentration, it significantly changed the SOC fractions in the topsoil and subsoil. The soil POC concentration and its contribution to SOC increased with an increasing elevation, whereas soil MAOC showed the opposite response. The elevational variations in SOC fractions and the POC/MAOC ratio were co-regulated by the fungal community structure and total nitrogen. Our results suggested that SOC stabilization in mountain meadows decreases with an increasing elevation and is driven by the fungal community structure, providing scientific guidance for SOC sequestration and stability in mountain meadows in subtropical areas.

Late Glacial and Holocene history of climate, vegetation landscapes and fires in South Taiga of Western Siberia based on radiocarbon dating and multi-proxy palaeoecological research of sediments from Shchuchye Lake

Abstract To investigate long-term relationships between climate, vegetation, landscape geochemistry and fires in the boreal forest zone of Western Siberia, a sediment core of 345 cm was collected from Shchuchye Lake (located in south taiga zone of southeast part of West Siberian plain) and investigated by spore-pollen, radiocarbon, LOI and charcoal analyses. Quantitative palaeoclimate was reconstructed based on pollen data. Investigation revealed 13.2 cal ka history of vegetation, climate, landscapes and fires. In the dry climate of Late Glacial, the landscape was treeless. Continuous permafrost existed in the soil. In the middle of the YD cooling 12.4–12.2 cal ka BP, our data showed warming that caused degradation of permafrost in soils and settlement of spruce in moist places. Later, thawing and accumulation of moisture in a local lowering in relief increased and a lake was formed. With the beginning of the Holocene, the climate sharply changed to warmer and wetter. Intensified surface flow caused accumulation of mineral and carbonate fraction in the lake. Dense birch forests spread on drylands. As a result, the leaching regime initiated the formation of podzols in the soil. At about 10.0 cal ka BP, Scots pine (Pinus sylvestris) quickly spread in the area of investigation. Fires became more frequent and more intense during the dry Late Glacial time, sharply decreasing with increased precipitation in the Early Holocene, and again moderately increasing with spread of pine forests in the mid Holocene. With the transition to Late Holocene (after 6.0 cal ka BP), the intensity of regional background fires and number of local fires decreased.

Improving the method for calculating carbon emissions from waste incineration: confirmed with carbon-14 testing of flue gas

An improved method was developed to calculate direct emissions from seven municipal solid waste incineration plants by adjusting the physical compositions of waste by invoking the proportion of co-incinerated waste and the bottom ash yield. The fossil carbon fractions of the waste components were determined by carbon-14 (14C) testing. Based on the improved method, direct emissions were in the range of 222–610 kg CO2-eq/t waste, corresponding to reductions of 3.4–221 kg CO2-eq/t waste compared with the method without waste composition adjustment. The 14C contents of the flue gas before and after gas cleaning were tested to validate the improved method, and indicated fossil CO2 emissions of 249–446 and 233–405 kg CO2-eq/t waste, respectively. The direct emissions obtained by the improved method were closer to the results of 14C testing, due to more accurate estimations of the actual waste composition. The method was further combined with a life cycle analysis of the waste incineration process, obtaining total carbon emissions in the range from –33.2 to 483 kg CO2-eq/t waste. The findings provide a new means of accurately calculating carbon emissions from waste incineration.Graphical