Search

Petroleum hydrocarbons (PHCs) can be biodegraded into CO 2 , and PHC-contaminated aquifers are always deemed as carbon sources. Fortunately, some carbon fixation microorganisms have been found in PHC-contaminated sites. However, most of the studies are related to volatile short-chain PHC, and few studies focus on long-chain PHC-contaminated sites. To reveal the carbon fixation microorganisms in these sites, in the study, a long-chain PHC polluted site in North China was selected. Through hydrochemical and metagenomics analysis, the structure and capacity of carbon fixing microorganisms in the site were revealed. Results showed that there were many kinds of carbon fixed microorganisms that were identified such as Flavobacterium, Pseudomonas. HP/4HB, rTCA, and DC/4HB cycles were dominated carbon fixation pathways. The long-chain PHC were weakly correlated with carbon fixation microorganisms, but it may stimulate the growth of some carbon fixation microorganisms, such as microorganisms involved in rTCA cycle. PRACTITIONER POINTS: The microorganisms with carbon fixation gene exist in the aquifer contaminated by long-chain petroleum hydrocarbon. Microorganisms that have the ability to degrade petroleum also have the ability to carbon fixation. Long-chain petroleum hydrocarbon may promote the growth of carbon fixation microorganisms., (© 2024 Water Environment Federation.)

Wood has always been an indispensable material in human society throughout history. Its efficient utilization is even more crucial today in achieving the Sustainable Development Goals (SDGs). However, its production, trade, use, and recycling are seldom systematically assessed, with Germany being an exception due to the extensive work conducted by the University of Hamburg and the Thünen Institute over the years. To provide a more precise account of wood use, this study employs oven-dry metric tonne as the reference unit to construct a static wood flow based on the material flow analysis and wood resource balance in Germany in 2020. The Sankey diagrams comprehensively visualize the flow and stock of wood in various sectors, including forests, sawmills, pulp mills, buildings, energy, and waste. Results showed that forest felling volume exceeded growth due to significant wood demand and export, while forest carbon sinks increased because more hardwood was retained in German forests. The building and construction sector was the largest consumer of primary wood products, accounting for 52.1 % of the total, followed by furniture (29.5 %) and packaging (14.0 %). All waste paper was used to produce recycled fiber pulp, whereas only 14 % of waste wood was employed in particle board production. The woody biomass energy, amounting to 142.4 TWh, provided approximately 4.4 % of Germany's primary energy consumption, with around half of it used in private households. In addition to apparent data, this study also uses resource allocation, carbon storage, and cascade potential as examples to demonstrate that wood flow is applicable for further in-depth analysis, supporting wood efficient utilization. It can even be applied to any country and period with sufficient data and conversion factors, but here, they also prevented this study from comprehensively describing past and future wood flows. [Display omitted] [ABSTRACT FROM AUTHOR]

Travertine and calcareous tufa are types of continental carbonates that form in subaerial environments near groundwater seepages, springs, and rivers. These deposits exist on all continents and can provide valuable information about past climates, environmental changes, and geological activity. A recent special issue of the journal Minerals focuses on the geochemistry of travertines and calcareous tufas, with contributions from researchers studying deposits in various locations around the world. The articles cover topics such as the formation processes, depositional environments, and diagenesis of these carbonate deposits, as well as their use as paleoclimate records and indicators of geothermal resources. The studies employ a multidisciplinary approach, combining techniques such as geochemistry, mineralogy, petrography, and isotopic analysis to gain a comprehensive understanding of these complex systems. Overall, the contributions highlight the importance of geochemical tracers in enhancing our knowledge of travertines and calcareous tufas. [Extracted from the article]

Blue Carbon is increasingly popular worldwide, and it also belongs to circular economy field which would last a long period in academy. To further understand the development and characteristics of Blue Carbon, this study uses CiteSpace software to perform quantitative analysis on literature published on Web of Science and Chinese CNKI database with the main topic of "Blue Carbon." The results show that: (1) Since 2009, increasing attention has been paid to Blue Carbon research, among which the United States, Australia and China are the leading countries. (2) Keywords such as "Blue Carbon," "mangrove," "carbon sequestration" and "carbon neutrality" are the high-frequency keywords appearing both in China and the World in recent years. (3) Spartina alterniflora, soil organic carbon, livestock, trophic cascade, biodiversity and seagrass ecosystem clustering are hot topics related to international Blue Carbon research, while organic carbon, seagrass-conservation, methodology, sustainable development, climate change, carbon neutralization, coastal zone and carbon storage are hot topics related to Chinese Blue Carbon research. In addition, based on the research trends of Blue Carbon, this paper attempts to sort out the research framework from three levels: core characteristics, theoretical basis and research methods, respectively. Facing a series of challenges brought by climate change, Blue Carbon research should strengthen the accurate estimations of Blue Carbon sink and its market potential, and explore the reasonable market mechanism and protection mechanism, to respond to realistic demands, solve major concerns and promote new progress in Blue Carbon theory and practice. [ABSTRACT FROM AUTHOR]

The land use, land-use change and forestry (LULUCF) sector, as a source and a sink of greenhouse gas (GHG) emissions, is critical for achieving carbon neutrality. Many academic journals have published papers on land use carbon emission or sink (LUCES), but LUCES reviews are relatively rare, which poses great challenges in accurately understanding the research progress and future prospects. This work analyzes the research characteristics, hotspots and future perspectives of LUCES research by using a bibliometric analysis (such as DDA, VOSviewer, CiteSpace software) and a review based on the data (6115 scientific papers) during 1991–2023 from the Web of Science (WoS) platform. We found that (1) over the past 33 years, it first presented a steady growth, then fluctuating growth, and finally a rapid growth trend in the yearly number of publications in LUCES research. The USA (17.31%), China (14.96%), and the UK (7.37%) occupy a dominant position in this research field. (2) The related LUCES research is interdisciplinary, which mainly cover science and technology, meteorology and atmospheric sciences, geology, and environmental sciences and ecology disciplines. (3) The research hotspot analysis on LUCES shows that these articles mostly covered the follow three aspects: ecosystem services, climate change, and carbon neutrality. (4) A review of the past LUCES literature suggests that it is mainly focused on exploring the forefront issues in terms of the definition and boundaries, evaluation method and influencing factors, etc. This work suggests that further research could explore the main scientific problems on quantification of land-based carbon neutrality, quantitative analysis of the impact mechanisms, as well as interdisciplinary research and collaborative governance needed for carbon neutrality. [ABSTRACT FROM AUTHOR]

The carbon budget concept states that the global mean temperature (GMT) increase is roughly linearly dependent on cumulative emissions of CO 2. The proportionality is measured as the transient climate response to cumulative emissions of carbon dioxide (TCRE). In this paper, the deviations of the carbon budget from the strict linear relationship implied by the TCRE are examined through the lens of a temperature response to an emission pulse (i.e., pulse response) and its relationship with a nonlinear TCRE. Hereby, two sources of deviation are distinguished: emission scenario and climate state dependence. The former stems from the scenario choice, i.e., the specific emission pathway for a given level of cumulative emissions and the latter from the change in TCRE with changing climatic conditions. Previous literature argues for scenario independence using a stylized set of emission scenarios, and offers a way to fit a nonlinear carbon budget equation. This paper shows how the pulse response, viewed as a Green's function, gives a unifying perspective on both scenario and state dependence. Moreover, it provides an optimization program that tests the scenario independence under the full range of emission pathways for a given set of constraints. In a setup chosen in this paper, the deviations stemming from emission pathway choices are less than 10 % of the overall temperature increase and gradually diminish. Moreover, using the pulse response as a Green's function, the scenario-dependent effects of a reduced-complexity climate model were replicated to a high degree, confirming that the behavior of scenario-dependent deviations can be explained and predicted by the shape of the pulse response. Additionally, it is shown that the pulse response changes with climatic conditions, through which the carbon budget state dependency is explained. Using a pulse response as an approximation for a state-dependent TCRE, an alternative method to derive a nonlinear carbon budget equation is provided. Finally, it is shown how different calibrations of a model can lead to different degrees of carbon budget nonlinearities. The analysis is done using FaIRv2.0.0, a simple climate emulator model that includes climate feedback modifying the carbon cycle, along with a one-box model used for comparison purposes. The Green's function approach can be used to diagnose both models' carbon budget scenario dependency, paving the way for future investigations and applications with other and more complex models. [ABSTRACT FROM AUTHOR]

The energy saving and emissions reduction of the construction industry are crucial for China to achieve the "carbon peaking and carbon neutrality" goals. In order to promote the green development of the life cycle of the construction industry and improve the efficiency of emissions reduction. This paper examines the spatial-temporal distribution of life cycle carbon emissions in China's construction industry (LCCECI) from 2004 to 2018. It uses the SBM-Malmquist total factor productivity (TFP) index to measure technological progress and establishes the spatial econometric model based on the STIRPAT model. The study investigates the driving factors of the LCCECI at the provincial and regional levels, aiming to provide suggestions for low-carbon development in the construction industry. The research results are as follows. © The growth in the SBM-Malmquist TFP index of the construction industry distinctly curbs the LCCECI. © Total population and urbanization level are not the primary driving factors for the LCCECI. The growth of per capita GDP significantly induces the LCCECI, while concurrently exhibiting a notable inhibitory effect on the LCCECI of neighboring regions. © The improvement of the SBM-Malmquist TFP index is conducive to the reduction of the LCCECI in the three major regions. The per capita GDP has the largest positive driving effect of the LCCECI in the eastern region, and the urbanization level the urbanization rate only significantly inhibits the growth of the LCCECI in the central region. [ABSTRACT FROM AUTHOR]

Global climate change, driven by increasing carbon emissions, has posed a significant challenge to both human survival and development, becoming a major issue for the sustainable progress of human society. This paper examines the characteristics and differences in the spatio-temporal distribution of carbon emissions and sinks across Wuhan Region that is stratified into three spatial levels: Hubei Province, the Wuhan Metropolitan Area, and Wuhan City. On a finer spatial scale within Wuhan, it uncovers the spatial correlations and disparities between carbon emissions and sinks. Accordingly, the paper proposes strategies and suggestions for reducing carbon emissions and enhancing carbon sinks at the provincial, metropolitan, and municipal levels. These findings are valuable for sustainable regional development and construction of low-carbon eco-cities. [ABSTRACT FROM AUTHOR]

In the global ecosystem, wetlands are vital carbon sinks, playing a crucial role in absorbing greenhouse gases such as carbon dioxide and mitigating global warming. Accurate estimation of wetland carbon content is essential for research on wetland carbon sinks. However, the carbon cycle of wetlands is complex, and the carbon sinking of wetlands is affected by climate, topography, water level conditions, vegetation types, soil types, and other factors. This has caused significant challenges in the estimation of wetland carbon sinks. In current studies, most research has focused on the impact of individual factors on wetland carbon sinks, often ignoring the interaction between various factors, which further leads to uncertainty in wetland carbon measurements. This paper aims to elucidate the process of the wetland carbon cycle, summarize the factors affecting wetland carbon sinks, and explore the interplay between various factors and their influence on wetland carbon sinks, aiming to provide theoretical support for the study of wetland carbon sinks. Additionally, this paper reviews the advantages and disadvantages of current wetland carbon measurement methods, proposes research directions for combining machine learning methods, identifies existing difficulties in current wetland carbon measurement, and offers suggestions to serve as a reference for future wetland carbon sink estimation and wetland management.Highlights: The potential and significance of wetland carbon sinks are explained. The advantages and disadvantages of current wetland carbon measurement techniques are summarized. The prospective method for integrating machine learning into integrated wetland carbon measurement is proposed. [ABSTRACT FROM AUTHOR]

Due to the serious problems with energy efficiency, carbon emissions, and thermal comfort of rural residences in northern China, an optimization of active and passive heating technologies for rural residences is necessary. In this paper, an optimization for rural residences in northern China is conducted with four objectives: the whole life cycle carbon emission; the annual energy consumption through heating, ventilation, and air conditioning systems; the annual cost; and thermal comfort. In addition, the optimization model with active–passive heating technology synergy is resolved by NSGA-II genetic algorithm. The active and passive design variables, including the type of air source heat pump, orientation, the type and thickness of envelope insulation, the layer of window glass, the window-to-wall area ratio, as well as sunspace parameters are preferred to obtain the optimal solution. The results indicate that the optimal solution obtained by the ideal point method gives the most outstanding performance. Compared with the prototype, the optimized carbon emissions in severe cold and cold regions decreased by 56.1% and 54.6%, respectively. The annual energy consumption decreased by 59.7% and 62.2%. Finally, the roof insulation thickness is the most sensitive design variable in Pareto-optimal solution sets. This paper offers significant guidance in the application of the optimization method of active–passive technology synergy to the energy-saving design of buildings. [ABSTRACT FROM AUTHOR]

Carbon supplementation strategies still have certain practical application constraints. Zn/Fe-based metal-organic frameworks (MOFs) nanoparticles that which are not toxic to Scenedesmus obliquus were successfully introduced into microalgal solutions to overcome low CO 2 solubility. The maximum specific surface area of MOFs reached 342.94 m 2 ·g -1 at a Zn/Fe molar ratio of 10/1. Under the optimal MOFs concentrations of 2.5 mg·L -1 , the conversion of inorganic carbon increased by 2.6-fold. When S. obliquuswas cultured in a MOFs-modified medium with 1.50 % CO 2 at 25 °C, the CO 2 mass transfer coefficient and mixing time reached 9.01 × 10 -3 min -1 and 55 s, respectively. The maximum chlorophyll-a content, biomass productivity, and CO 2 fixation efficiency reached 32.57 mg·L -1 , 0.240 g·L -1 ·d -1 and 21.6 %, respectively. Enriching CO 2 for ribulose-1,5-bisphosphate carboxylase/oxygenase carboxylation by MOFs may be the key to improving the photosynthetic efficiency of microalgae. This strategy could serve as a reference for improving the microalgal CO 2 fixation efficiency., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Deciphering riverine dissolved carbon dynamics is pivotal for a comprehensive picture of the global carbon cycle. Through rigorous in-situ sampling across the Pearl River Basin (PRB), our investigation reveals the Pearl River networks function as a significant carbon source, with the annual carbon dioxide (CO 2 ) emission of 2.57 ± 1.94 Tg C, which offsets 10 ± 8 % of the forest carbon sequestration or 65 ± 49 % carbon sink via chemical weathering in the PRB. Based on the mass balance of 222 Rn, we initially reveal that the contributions of water flux from the hyporheic zone increased with the river orders (Hack Order) across both dry and wet seasons. Conversely, the evasion rates of dissolved CO 2 (CO 2 *) and dissolved inorganic carbon (DIC) from the hyporheic zone into river channels exhibited a decline with the increasing river orders. The hyporheic exchange contributes 4 - 11 % of the lateral and vertical DIC losses, thereby is a key mechanism in the riverine carbon cycle. Furthermore, CO 2 * derived from the hyporheic zone was ∼4 times of riverine CO 2 emissions and this CO 2 * flux from the hyporheic zone was buffered into carbonates/bicarbonates in river channels, due to the high riverine pH resulted from carbonate weathering in the basin. These results not only highlight the substantial role of carbonates and hyporheic processes in modulating riverine carbon fluxes but also signify their broader implications on understanding riverine carbon dynamics at both regional and global scales., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Organophosphorus pesticides (OPPs) are important chemical stressors in aquatic ecosystems, and they attract increasing more attentions recently. However, the impacts of different OPPs on carbon cycling remain unclear, particularly for those functional-yet-uncultivable microbes. This study investigated the change in lake aquatic microbial communities in the presence of dichlorvos, monocrotophos, omethoate and parathion. All OPPs significantly inhibited biomass (p < 0.05) and the expression of carbon cycle-related cbbLG gene (p < 0.01), and altered aquatic microbial community structure, interaction, and assembly. Variance partitioning analysis showed a stronger impact of pesticide type on microbial biomass and community structure, where pesticide concentration played more significant roles in carbon cycling. From analysis of cbbLG gene and PICRUSt2, Luteolibacter and Verrucomicrobiaceae assimilated inorganic carbon through Wood-Ljungdahl pathway, whereas it was Calvin-Benson-Bassham cycle for Cyanobium PCC-6307. This work provides a deeper insight into the behavior and mechanisms of microbial community change in aquatic system in response to OPPs, and explicitly unravels the impacts of OPPs on their carbon-cycling functions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The dune ecosystem plays a significant role in the global carbon cycle. The Horqin Sandy Land is a typical semi-arid fragile ecosystem in northern China. Understanding the magnitudes and dynamics of carbon dioxide fluxes within this region is essential for understanding the carbon balance. Used 6 years (2013-2018) measurements from an eddy-covariance system, we analyzed the dynamic patterns of net ecosystem carbon exchange (NEE), gross primary production (GPP), and ecosystem respiration (Reco) of the dune ecosystem in Horqin Sandy Land and examined their responses to climate factors with a focus on the precipitation. The results showed that the NEE of the dune ecosystem fluctuated from -166 to 100 gCO 2 ·m -2 ·year -1 across the 6 growing seasons, with an average of -56 gCO 2 ·m -2 ·year -1 . The precipitation was not a key factor influencing the carbon flux variability. During the mid-growth stage, GPP was primarily affected by the effective precipitation frequency (R 2 ranging from 0.65 to 0.85, P < 0.05), followed by fractional vegetation cover (R 2 ranging from 0.65 to 0.68, P < 0.05). However, in the early and late growth stages, temperature predominantly drove the carbon flux (R 2  = 0.75, P < 0.01). The interannual variability of carbon flux can be predominantly elucidated by phenological indicators such as CO 2 uptake (CU start ), end of CO 2 uptake (CU end ), CO 2 uptake period (CUP), and Spring lag. The results demonstrated the dune ecosystem is a weak carbon sink in semi-arid ecosystems. Furthermore, we emphasized the significance of effective precipitation frequency in regulating carbon fluxes. Our results provide a foundational understanding of the carbon balance in semi-arid ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The persistence of dissolved organic matter (DOM) plays a crucial role in the cycling and distribution of carbon and nutrients. Nonetheless, our understanding of how environmental alterations affect the persistence of sedimentary DOM remains incomplete. Excitation Emission Fluorescence Matrix-Parallel Factor Analysis (EEM-PARAFAC) was used to examine the fluorescence and compositional characteristics of hydrophilic and hydrophobic DOM (separated using XAD-8 resin) within sediments from twelve lakes and reservoirs. Fluorescence analysis indicated that DOM persistence is dependent on the proportions of the three components derived from PARAFAC. The Mantel test showed that climatic factors had the most significant impact on DOM persistence (Mantel's r = 0.46-0.54, Mantel's p = 0.001-0.007), while anthropogenic (Mantel's r = 0.24-0.32, Mantel's p = 0.03-0.05) and hydrological factors (Mantel's r = 0.03-0.22, Mantel's p = 0.06-0.40) had a somewhat lesser influence. Environmental changes resulted in a consistent decline in DOM persistence from Northeast to Southwest China, accompanied by an increase in gross primary productivity (GPP). Reduced DOM persistence due to climate, hydrological, and anthropogenic factors may lead to elevated concentrations of total phosphorus (TP), contributing to deteriorating water quality and events such as algal blooms. The decline in water quality due to reduced DOM persistence in lakes with high GPP can exacerbate the transition from carbon sinks to carbon sources. Consequently, the persistence of sedimentary DOM significantly influences nutrient and carbon cycling in lakes. Investigating DOM persistence in lakes across diverse geographic locations offers a new perspective on lake eutrophication and carbon emissions. Furthermore, it is crucial to develop targeted recommendations for lake restoration and management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Urban green space is a direct way to improve the carbon sink capacity of urban ecosystems. The carbon storage assessment of megacity green spaces is of great significance to the service function of urban ecosystems and the management of urban carbon zoning in the future. Based on multi-period remote sensing image data, this paper used the CASA model and the InVEST model to analyze the spatio-temporal variation and driving mechanism of carbon storage in Shenzhen green space and discussed the applicability of the two models to the estimation of carbon storage in urban green space. The research results showed that, from 2008 to 2022, in addition to the rapid expansion of construction land, the area of green space and other land types in Shenzhen showed a significant decrease trend. The estimation results of the carbon storage model showed that the carbon storage of green space shows a significant trend of reduction from 2008 to 2022, and the reduction amounts are 0.8 × 106 t (CASA model) and 0.64 × 106 t (InVEST model), respectively. The evaluation results of the model show that, in megacities, the spatial applicability of InVEST model is lower than that of CASA model, and the CASA model is more accurate in estimating the carbon storage of urban green space. The research results can provide a scientific basis for the assessment of the carbon sink capacity of megacity ecosystems with the goal of "dual carbon". [ABSTRACT FROM AUTHOR]

The land-use, land-use change and forestry (LULUCF) sector is receiving increasing attention in climate change mitigation and greenhouse gas (GHG) emission offsetting. The sector itself and measures applied to mobilize this sector in order to tackle climate change are dominant in nationally determined contributions under the Paris Agreement as well as in national strategies, as in the case of Lithuania. Lithuania has set the goal of becoming a carbon-neutral country in 2050, reducing GHGs by 80% compared to 1990 and offsetting the remaining 20% through the LULUCF sector. Therefore, this paper aims at analyzing historical land-use changes in 1990–2021, as reported for the United Nations Framework Convention on Climate Change (UNFCCC) secretariat, and LULUCF's potential to achieve climate change mitigation goals, taking into account different land-use change scenarios (business as usual, forest development, forest development + additional measures and forest land 40% + additional measures) for 2030 and 2050 in Lithuania. The scenarios are based on historical and potential future policy-based land-use changes. Projections of GHG emissions/removals for different scenarios are prepared according to the Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories (2006) by the Intergovernmental Panel on Climate Change (IPCC). The results indicate that land-use changes over the period 1990–2021 remained rather stable, with some increases in forest area and grassland at the expense of cropland. The whole LULUCF sector acted as a carbon sink in most cases, forests being a key category for removal. However, reaching climate neutrality in 2050 might be challenging, as the goal to offset 20% of remaining GHG emission compared to 1990 through LULUCF would not be met in any of the scenarios analyzed, even the scenario of maximal forest-area development and additional measures. Considering the high historical GHG-removal fluctuations and the uncertainties of the sector itself, caution should be taken when relying on LULUCF's potential to reach the set goals. [ABSTRACT FROM AUTHOR]

Application of biochar has been demonstrated to be a successful strategy for boosting soil carbon sequestration and altering the agricultural soil carbon cycle. However, in the studies involving biochar worldwide, the effects of different types of biochar on the soil carbon component response direction and increase are not consistent. Therefore, to assess the effects of applying four types of biochar during the soil carbon cycle on carbon components on a farmland, we performed a meta-analysis of 1150 comparisons from 86 peer-reviewed publications. Generally speaking, the types of biochar raw materials have a significant impact on soil carbon cycle. The application of chaff biochar significantly inhibited (10.0 %) soil respiration, while the application of manure biochar (47.0 %), straw biochar (11.2 %) and wood biochar (8.7 %) showed a strong promotion effect on CO 2 emission. In addition, although the soil organic C, microbial biomass C and dissolved organic C all had positive responses to the application of the four biochar types, the degree and increase in their response varied greatly due to the differences in biomass raw materials. Moreover, by increasing the biochar rates applied to coarse-textured soils with low average annual rainfall and an average temperature under controlled circumstances, the relative increase in SOC was encouraged. Meanwhile, applying low temperature pyrolytic biochar (≤400 °C) at a lower rate (<25 t/ha) in the long-term experiment (>3 years) is more beneficial to soil C sequestration and emission reduction. Hence, climatic conditions, agricultural management practices, and initial soil properties jointly constrained and influenced the ability of biochar to alter the soil C cycle. Based on this, our research offers a fresh viewpoint for making a profound study biochar-enhanced soil C cycle., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The transfer of particulate organic carbon (POC) to dissolved organic carbon (DOC; OC transfer P-D ) is crucial for the marine carbon cycle. Sediment resuspension driven by hydrodynamic forcing can affect the burial of sedimentary POC and benthic biological processes in marginal sea. However, the role of sediment grain size fraction on OC transfer P-D and the subsequent impact on OC cycling remain unknown. Here, we conduct sediment resuspension simulations by resuspending grain-size fractionated sediments (< 20, 20-63, and > 63 μm) into filtered seawater, combined with analyses of OC content, optical characteristics, 13 C and 14 C isotope compositions, and molecular dynamics simulations to investigate OC transfer P-D and its regulations on OC bioavailability under sediment resuspension. Our results show that the relative intensities of terrestrial humic-like OC (refractory DOC) increase in resuspension experiments of < 20, 20-63, and > 63 μm sediments by 0.14, 0.01, and 0.03, respectively, likely suggesting that sediment resuspension drives refractory DOC transfer into seawater. The variations in the relative intensities of microbial protein-like DOC are linked to the change of terrestrial humic-like OC, accompanied by higher DOC content and reactivity in seawater, particularly in finer sediments resuspension experiments. This implies that transferred DOC likely fuels microbial growth, contributing to the subsequent enhancement of DOC bioavailability in seawater. Our results also show that the POC contents increase by 0.35 %, 0.66 %, and 0.93 % in < 20, 20-63, and > 63 μm resuspension experiments at the end of incubation, respectively. This suggests that the re-absorption of OC on particles may be a significant process, but previously unrecognized during sediment resuspension. Overall, our findings suggest that sediment resuspension promotes the OC transfer P-D , and the magnitudes of OC transfer P-D further influence the DOC and POC properties by inducing microbial production and respiration. These processes significantly affect the dynamics and recycling of biological carbon pump in shallow marginal seas., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial intersts or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Carbon-fixing bacterial communities are essential drivers of carbon fixation in estuarine ecosystems that critically affect the global carbon cycle. This study compared the abundances of the Calvin cycle functional genes cbbL and cbbM and Reductive tricarboxylic acid cycle gene aclB, as well as compared carbon-fixing bacterial community features in the two estuaries, predicted potential ecological functions of carbon-fixation bacteria, and analyzed their symbiosis strategies in two estuaries having different geographical distributions. Gammaproteobacteria was the dominant carbon-fixing bacterial community in the two estuaries. However, a higher number of Alphaproteobacteria were noted in the Liaohe Estuary, and a higher number of Betaproteobacteria were found in the Yalujiang Estuary. The carbon-fixing functional gene levels exhibited the order of aclB > cbbL > cbbM, and significant effects of Cu, Pb, and petroleum were observed (p < 0.05). Nitrogen-associated nutrient levels are major environmental factors that affect carbon-fixing bacterial community distribution patterns. Spatial factors significantly affected cbbL carbon-fixing functional bacterial community structure more than environmental factors. With the increase in offshore distance, the microbial-led processes of methylotrophy and nitrogen fixation gradually weakened, but a gradual strengthening of methanotrophy and nitrification was observed. Symbiotic network analysis of the microorganisms mediating these ecological processes revealed that the carbon-fixing bacterial community in these two estuaries had a non-random symbiotic pattern, and microbial communities from the same module were strongly linked among the carbon, nitrogen, and sulfur cycle. These findings could advance the understanding of carbon fixation in estuarine ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The increases in extent and frequency of extreme drought events and increased nitrogen (N) deposition due to global change are expected to have profound impacts on carbon cycling in semi-arid grasslands. However, how ecosystem CO 2 exchange processes respond to different drought scenarios individually and interactively with N addition remains uncertain. In this study, we experimentally explored the effects of different drought scenarios (early season extreme drought, 50 % reduction in precipitation amount, and 50 % reduction in precipitation events) and N addition on net ecosystem CO 2 exchange (NEE), ecosystem respiration (ER), and gross ecosystem productivity (GEP) over three growing seasons (2019-2021) in a semi-arid grassland in northern China. The growing-season ecosystem carbon fluxes in response to drought and N addition were influenced by inter-annual precipitation changes, with 2019 as a normal precipitation year, and 2020 and 2021 as wet years. Early season extreme drought stimulated NEE by reducing ER. 50 % reduction in precipitation amount decreased ER and GEP consistently in three years, but only significantly suppressed NEE in 2019. 50 % reduction in precipitation events stimulated NEE. Nitrogen addition stimulated NEE, ER, and GEP, but only significantly in wet years. The structural equation models showed that changes in carbon fluxes were regulated by soil moisture, soil temperature, microbial biomass nitrogen (MBN), and the key plant functional traits. Decreased community-weighted means of specific leaf area (CWM SLA ) was closely related to the reduced ER and GEP under early season extreme drought and 50 % reduction in precipitation amount. While increased community-weighted means of plant height (CWM PH ) largely accounted for the stimulated ER and GEP under 50 % reduction in precipitation events. Our study stresses the distinct effects of different drought scenarios and N enrichment on carbon fluxes, and highlights the importance of soil traits and the key plant traits in determining carbon exchange in this water-limited ecosystem., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Algae-driven photosynthetic CO 2 fixation is a promising strategy to mitigate global climate changes and energy crises. Yet, the presence of metal nanoparticles (NPs), particularly dissolvable NPs, in aquatic ecosystems introduces new complexities due to their tendency to release metal ions that may perturb metabolic processes related to algal CO 2 fixation. This study selected six representative metal NPs (Fe 3 O 4 , ZnO, CuO, NiO, MgO, and Ag) to investigate their impacts on CO 2 fixation by algae (Chlorella vulgaris). We discovered an intriguing phenomenon that bivalent metal ions released from the metal NPs, especially from ZnO NPs, substituted Mg 2+ within the porphyrin ring. This interaction led to 81.8% and 76.1% increases in Zinc-chlorophyll and Magnesium-chlorophyll contents within algal cells at 0.01 mM ZnO NPs, respectively. Integrating metabolomics and transcriptomics analyses revealed that ZnO NPs mainly promoted the photosynthesis-antenna protein pathway, porphyrin and chlorophyll metabolism, and carbon fixation pathway, thereby mitigating the adverse effects of Zn 2+ substitution in light harvesting and energy transfer for CO 2 fixation. Ultimately, the genes encoding Rubisco large subunit (rbcL) responsible for CO 2 fixation were upregulated to 2.60-fold, resulting in a 76.3% increase in carbon fixation capacity. Similar upregulations of rbcL expression (1.13-fold) and carbon fixation capacity (76.1%) were observed in algal cells even at 0.001 mM ZnO NPs, accompanied by valuable lipid accumulation. This study offers novel insights into the molecular mechanism underlying NPs on CO 2 fixation by algae and potentially introduces strategies for global carbon sequestration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Australia, characterized by extensive and heterogeneous terrestrial ecosystems, plays a critical role in the global carbon cycle and in efforts to mitigate climate change. Prior research has quantified vegetation productivity and carbon balance within the Australian context over preceding decades. Nonetheless, the responses of vegetation and carbon dynamics to the evolving phenomena of climate change and escalating concentrations of atmospheric carbon dioxide remain ambiguous within the Australian landscape. Here, we used LPJ-GUESS model to assess the impacts of climate change on Gross Primary Productivity (GPP) and Net Biome Productivity (NBP) of carbon for the state of New South Wales (NSW) in southeastern Australia. LPJ-GUESS simulations were driven by an ensemble of 27 global climate models under different emission scenarios. We investigated the change of GPP for different vegetation types and whether NSW ecosystems will be a net sink or source of carbon under climate change. We found that LPJ-GUESS successfully simulated GPP for the period 2003-2021, demonstrating a comparative performance with GPP derived from upscaled eddy covariance fluxes (R 2  = 0.58, nRMSE = 14.2 %). The simulated NBP showed a larger interannual variation compared with flux data and other inversion products but could capture the timing of rainfall-driven carbon sink and source variations in 2015-2020. GPP would increase by 10.3-19.5 % under a medium emission scenario and 19.7-46.8 % under a high emission scenario. The mean probability of NSW acting as a carbon sink in the future showed a small decrease with a large uncertainty with >8 of the 27 climate models indicating an increased potential for carbon sink. These findings emphasize the significance of emission scenarios in shaping future carbon dynamics but also highlight considerable uncertainties stemming from different climate projections. Our study represents a baseline for understanding natural ecosystem dynamics and their key role in governing land carbon uptake and storage in Australia., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Photoautotrophic marine ecosystems can lock up organic carbon in their biomass and the associated organic sediments they trap over millennia and are thus regarded as blue carbon ecosystems. Because of the ability of marine ecosystems to lock up organic carbon for millennia, blue carbon is receiving much attention within the United Nations' 2030 Agenda for Sustainable Development as a nature-based solution (NBS) to climate change, but classically still focuses on seagrass meadows, mangrove forests, and tidal marshes. However, other coastal ecosystems could also be important for blue carbon storage, but remain largely neglected in both carbon cycling budgets and NBS strategic planning. Using a meta-analysis of 253 research publications, we identify other coastal ecosystems-including mud flats, fjords, coralline algal (rhodolith) beds, and some components or coral reef systems-with a strong capacity to act as blue carbon sinks in certain situations. Features that promote blue carbon burial within these 'non-classical' blue carbon ecosystems included: (1) balancing of carbon release by calcification via carbon uptake at the individual and ecosystem levels; (2) high rates of allochthonous organic carbon supply because of high particle trapping capacity; (3) high rates of carbon preservation and low remineralization rates; and (4) location in depositional environments. Some of these features are context-dependent, meaning that these ecosystems were blue carbon sinks in some locations, but not others. Therefore, we provide a universal framework that can evaluate the likelihood of a given ecosystem to behave as a blue carbon sink for a given context. Overall, this paper seeks to encourage consideration of non-classical blue carbon ecosystems within NBS strategies, allowing more complete blue carbon accounting., (© 2024 John Wiley & Sons Ltd.)

Soil and water conservation measures have good carbon sinking capacity, and the comprehensive management of small watersheds involves plant measures, engineering measures and farming measures, which profoundly affect the capacity of the three major carbon pools of soil, vegetation and water bodies, making them an ideal place to carry out the monitoring and accounting of carbon sinks in soil and water conservation. The purpose of this paper is to monitor and evaluate the carbon sinks of soil and vegetation, to provide techniques and methods for the implementation of dynamic monitoring and evaluation of carbon sinks in soil and water conservation projects, and to provide theoretical and methodological support for the participation of soil and water conservation projects in carbon trading and the study of the formulation of relevant rules. In this study, field sampling and analysis, LiDAR, remote sensing and other related parameters were used to account for the carbon storage of vegetation carbon pools and soil carbon pools in the Luodi River sub-watershed, Changting County, Fujian Province, from 2001 to 2022, and to evaluate the carbon sink capacity of the various soil and water conservation management measures in the sub-watershed. The results show that after 21 years of comprehensive management, various soil and water conservation measures in the Luodi River sub-basin have significantly enhanced the role and capacity of carbon sinks, and the sub-basin's carbon stock increased by 3.97 × 104 t, with an average annual increase of 1.89 × 103 t/a. From the perspective of the carbon pools, the carbon stocks of soil and vegetation increased by 73.73% and 346.41%, respectively, from 2001 to 2022. The total carbon sunk in the sub-watershed reached 2.90 × 104 t, of which 1.57 × 104 t was in soil carbon sinks and 1.34 × 104 t was in vegetation carbon sinks. There were differences in the ability of various measures to enhance the increment of the carbon sink, among which the Castanea mollissima and the Fertilized Pinus massoniana Forest had the most obvious increase in carbon sunk, followed by the Mixed Needleleaf and Broadleaf Forest, the Nurture and Management Pinus massoniana Forest, and the Horizontal terraces Pinus massoniana Forest, and lastly, the Closed Management Forest and the Morella rubra. Various soil and water conservation measures have obvious effects of carbon retention, carbon sequestration and sink enhancement, while Castanea mollissima and Fertilized Pinus massoniana Forest and other forests that implement land preparation and afforestation with fertilization and nourishment measures have more significant increases in carbon sink capacity, which is an effective measure to improve the benefits of soil and water conservation and increase the amount of carbon sinks. [ABSTRACT FROM AUTHOR]

Databases of 3D paleoclimate model simulations are increasingly used within global biogeochemical models for the Phanerozoic Eon. This improves the accuracy of the surface processes within the biogeochemical models, but the approach is limited by the availability of large numbers of paleoclimate simulations at different p CO 2 levels and for different continental configurations. In this paper we apply the Frame Interpolation for Large Motion (FILM) deep learning method to a set of Phanerozoic paleoclimate model simulations to upscale their time resolution from one model run every ∼25 million years to one model run every 1 million years (Myr). Testing the method on a 5 Myr time-resolution set of continental configurations and paleoclimates confirms the accuracy of our approach when reconstructing intermediate frames from configurations separated by up to 40 Myr. We then apply the method to upscale the paleoclimate data structure in the SCION climate-biogeochemical model. The interpolated surface temperature and runoff are reasonable and present a logical progression between the original key frames. When updated to use the high-time-resolution climate data structure, the SCION model predicts climate shifts that were not present in the original model outputs due to its previous use of widely spaced datasets and simple linear interpolation. We conclude that a time resolution of ∼10 Myr in Phanerozoic paleoclimate simulations is likely sufficient for investigating the long-term carbon cycle and that deep learning methods may be critical in attaining this time resolution at reasonable computational expense, as well as for developing new fully continuous methods in which 3D continental processes are able to translate over a moving continental surface in deep time. However, the efficacy of deep learning methods in interpolating runoff data, compared to that of paleogeography and temperature, is diminished by the heterogeneous distribution of runoff. Consequently, interpolated climates must be confirmed by running a paleoclimate model if scientific conclusions are to be based directly on them. [ABSTRACT FROM AUTHOR]

The poverty-stricken counties on the Qinghai-Tibet Plateau are characterized by ecological vulnerability and ecological degradation, which are vulnerable to economic development and human activities, thereby leading to frequent alterations of Land carbon sink changes. Therefore, it is of great significance to study the changes of land carbon sink capacity during the process of eradication of extreme poverty in poverty-stricken counties. Using remote sensing images and socio-economic data, this paper constructed land transfer matrix and land carbon sink model to analyze the changes of land carbon sink capacity in poverty-stricken counties and identified the relevant impact factors through geographic detectors. The results show significant changes in carbon sink-type land and a continuous decrease in the snow area, resulting in an obvious trend of grassland area decrease and barren area increase. Land carbon sink capacity of poverty-stricken counties during the eradication of extreme poverty is higher with an added value of 2.74 times than that before this period. Using the geographic detector to analyze the related factors, strong explanatory power was found in cash crops per capita, share of secondary industry, population density and per capita savings on the changes of carbon sink capacity in poverty-stricken counties. [ABSTRACT FROM AUTHOR]

The "Dual Carbon" initiative is a two-stage carbon reduction goal proposed by China, with significant implications for global climate change mitigation. This article examines the impact of the "Dual Carbon" strategy on China's forestry development and explores how to leverage this strategy to facilitate the transformation and advancement of the forestry sector. Current review indicated that forestry has the advantage of achieving higher emission reduction targets at a low cost. Starting with an overview of the "Dual Carbon" strategy, this paper analyzes the carbon sequestration potential of plants and soil, and the challenges and opportunities faced by forestry development under this framework. Furthermore, we outline implementation pathways for forestry development, aiming to provide insights for the progress of China's forestry sector. Overall, it should be noted that the priority is to vigorously develop timber resources, and we also need to vigorously develop and protect forestry talent with the support of China's policies. By trapping into the carbon storage capabilities and leveraging carbon trading mechanisms of forests, a favorable ecological environment can be created, thus achieving the goal of carbon neutrality. Highlights: • Forest development and its carbon sinks, attributed to plant and soil have the potential in carbon sequestration process, thus helping China achieve carbon neutrality. • The supply of forest products and the balance of economic growth and environmental protection are the key difficulties under the "Dual Carbon" strategy. • Trading forest carbon sinks can boost China's sequestration. [ABSTRACT FROM AUTHOR]

Extreme heatwaves have become more frequent and severe in recent decades, and are expected to significantly influence carbon fluxes at regional scales across global terrestrial ecosystems. Nevertheless, accurate prediction of future heatwave impacts remains challenging due to a lack of a consistent comprehension of intrinsic and extrinsic mechanisms. We approached this knowledge gap by analyzing the complexity factors in heatwave studies, including the methodology for determining heatwave events, divergent responses of individual ecosystem components at multiple ecological and temporal scales, and vegetation status and hydrothermal environment, among other factors. We found that heatwaves essentially are continuously changing compound environmental stress that can unfold into multiple chronological stages, and plant physiology and carbon flux responses differs in each of these stages. This approach offers a holistic perspective, recognizing that the impacts of heatwaves on ecosystems can be better understood when evaluated over time. These stages include instantaneous, post-heatwave, legacy, and cumulative effects, each contributing uniquely to the overall impact on the ecosystem carbon cycle. Next, we investigated the importance of the timing of heatwaves and the possible divergent consequences caused by different annual heatwave patterns. Finally, a conceptual framework is proposed to establish a united foundation for the study and comprehension of the consequences of heatwaves on ecosystem carbon cycle. This instrumental framework will assist in guiding regional assessments of heatwave impacts, shedding light on the underlying mechanisms responsible for the varied responses of terrestrial ecosystems to specific heatwave events, which are imperative for devising efficient adaptation and mitigation approaches., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Inc.)

A comprehensive decarbonization approach is reported, involving Direct Separation Reactors (DSRs) and eco-efficient energy sources in the production of hydrated lime. Environmental and economic impacts are calculated through an in-depth life-cycle cradle-to-grave assessment. Integrating a DSR kiln with carbon capture technologies (CCTs) attained a remarkable 65% reduction of CO2 emissions during hydrated lime production, with a minimum environmental impact from the CCT itself. Fully electrified DSR kilns, powered by renewable energy sources, achieve an astonishing 94% decrease in CO2 emissions when compared to conventional reference scenarios, all without adverse environmental effects. In limebased plasters, combining DSR kilns, natural carbonation, and eco-efficient energy sources, particularly with the inclusion of natural gas, leads to carbon negativity. This efficiently offsets all production emissions and even cuts back an additional 30%. In the case of fully electrified DSR kilns, the results are a remarkable 149% CO2 emission reduction throughout the entire cradle-to-grave lifecycle. Carbon capture technologies reduce carbon tax costs by up to 26%, thereby enhancing the economic sustainability of these endeavours. To realize a swift and effective decarbonization of the lime industry, a harmonized effort is imperative and involves balancing the interests of the private sector, environmental protection, and promoting societal well-being, all within a supportive regulatory framework. [ABSTRACT FROM AUTHOR]

Land cover and its changes over time are significant for better understanding the Earth's fundamental characteristics and processes, such as global climate change, hydrology, and the carbon cycle. A number of land cover-geoprocessing models have been proposed for land cover-data production with different spatial and temporal resolutions. With the massive growth in land cover data and the increasing demand for efficient model utilization, developing efficient and convenient land cover-geoprocessing models has become a formidable challenge. Although some model-migration methods have been proposed for handling the massive data, the intricacy of land cover-data and -heterogeneity models frequently prevent current strategies from directly meeting demand. In this paper, we propose the PAMC-LC-containerization approach to overcome the difficulties associated with moving existing land cover models in the open web environment. Based on the idea of model migration, we design a standardized model description and hierarchical encapsulation strategy for land cover models, and develop migration and deployment methods. Furthermore, we assess the viability and efficacy of the proposed approach by using coupled workflows for model migration and the introduction of visualization on the Mts-WH dataset and the Google dataset. The experimental results show that the PAMC-LC approach can simplify and streamline the model migration process, with important ramifications for increasing productivity, reusing models, and lowering additional data-transmission costs. [ABSTRACT FROM AUTHOR]

Carbon emissions and land use intensity serve as crucial indicators of land management. This paper proposes a methodological framework to elucidate the sustainability of carbon emissions in rural areas via a coordination model, scrutinizes the correlation with land use intensity, and investigates the significance of influential factors. The study focuses on village-level units within Ningde City, and finds the pronounced spatial heterogeneity characterizing the distribution of carbon emissions across different villages: (1) Villages exhibiting high levels of carbon emissions are predominantly concentrated in the southeast region, whereas those with low carbon emission levels are primarily clustered in the northwest region. The majority of the villages serve as net carbon emission sources. (2) Spatial disparities exist in the impact of land use intensity on economic benefits from carbon sources, ecological benefits from carbon sinks, and carbon emission sustainability. (3) Significant variations exist in the influence of factors affecting land use intensity, economic benefits of carbon sources, ecological benefits of carbon sinks, and the sustainability of carbon emissions in rural areas. These findings could guide governments in implementing distinct land use control policies and provide a framework for assessing carbon emission sustainability within land management strategies. [ABSTRACT FROM AUTHOR]

As a world-class urban agglomeration, the Yangtze River Delta urban agglomeration is significant for China's carbon neutrality strategy when calculating the carbon budget and dividing carbon compensation zones. This paper focused on 129 county-level cities in the core area of the Yangtze River Delta urban agglomeration, calculating the carbon budget for 2000–2020 using night-time light data and analyzing the evolution of spatiotemporal patterns. On this basis, a carbon compensation zoning model was constructed using the K-means algorithm; 129 cities were divided into different carbon compensation zones after combining this model with the main functional zones. The results showed that (1) the carbon emissions increased, with overall stabilization after 2012. The distribution of high carbon emission areas evolved from a "core-periphery" pattern into a "Z-shaped" pattern. Ecological carbon sinks showed a continuous decline, with the southern sinks performing better than the northern ones. (2) The carbon budget of the study area showed a deficit, gradually widening and exhibiting an unbalanced spatial distribution characterized by a "high in the south and low in the north" pattern. (3) Eleven types of carbon compensation zones were designated after overlaying the main functional zones. Low-carbon development suggestions were proposed for each zone type. [ABSTRACT FROM AUTHOR]

Achieving climate targets requires mitigation against climate change but also understanding of the response of land and ocean carbon systems. In this context, global soil carbon stocks and their response to environmental changes are key. This paper quantifies the global soil carbon feedbacks due to changes in atmospheric CO 2 , and the associated climate changes, for Earth system models (ESMs) in CMIP6. A standard approach is used to calculate carbon cycle feedbacks, defined here as soil carbon-concentration (βs) and carbon-climate (γs) feedback parameters, which are also broken down into processes which drive soil carbon change. The sensitivity to CO 2 is shown to dominate soil carbon changes at least up to a doubling of atmospheric CO 2. However, the sensitivity of soil carbon to climate change is found to become an increasingly important source of uncertainty under higher atmospheric CO 2 concentrations. [ABSTRACT FROM AUTHOR]

Grasslands are among the most widespread environments on Earth, yet we still have poor knowledge of their microbial-mediated carbon cycling in the context of human activity and climate change. We conducted a systematic bibliometric analysis of 1,660 literature focusing on microbial-mediated grassland carbon cycling in the Scopus database from 1990 to 2022. We observed a steep increase in the number of multidisciplinary and interdisciplinary studies since the 2000s, with focus areas on the top 10 subject categories, especially in Agricultural and Biological Sciences. Additionally, the USA, Australia, Germany, the United Kingdom, China, and Austria exhibited high levels of productivity. We revealed that the eight papers have been pivotal in shaping future research in this field, and the main research topics concentrate on microbial respiration, interaction relationships, microbial biomass carbon, methane oxidation, and high-throughput sequencing. We further highlight that the new research hotspots in microbial-mediated grassland carbon cycling are mainly focused on the keywords "carbon use efficiency," "enzyme activity," "microbial community," and "high throughput sequencing." Our bibliometric analysis in the past three decades has provided insights into a multidisciplinary and evolving field of microbial-mediated grassland carbon cycling, not merely summarizing the literature but also critically identifying research hotspots and trends, the intellectual base, and interconnections within the existing body of collective knowledge and signposting the path for future research directions. [ABSTRACT FROM AUTHOR]

Background: Carbon (C) sink and stock are among the most important ecosystem services provided by forests in climate change mitigation policies. In this context, old-growth forests constitute an essential reference point for the development of close-to-nature silviculture, including C management techniques. Despite their small extent in Europe, temperate old-growth forests are assumed to be among the most prominent in terms of biomass and C stored. However, monitoring and reporting of C stocks is still poorly understood. To better understand the C stock amount and distribution in temperate old-growth forests, we estimated the C stock of two old-growth stands in the Dinaric Alps applying different assessment methods, including direct and indirect approaches (e.g., field measurements and allometric equations vs. IPCC standard methods). This paper presents the quantification and the distribution of C across the five main forest C pools (i.e., aboveground, belowground, deadwood, litter and soil) in the study areas and the differences between the applied methods. Results: We report a very prominent C stock in both study areas (507 Mg C ha− 1), concentrated in a few large trees (36% of C in 5% of trees). Moreover, we found significant differences in C stock estimation between direct and indirect methods. Indeed, the latter tended to underestimate or overestimate depending on the pool considered. Conclusions: Comparison of our results with previous studies and data collected in European forests highlights the prominence of temperate forests, among which the Dinaric Alps old-growth forests are the largest. These findings provide an important benchmark for the development of future approaches to the management of the European temperate forests. However, further and deeper research on C stock and fluxes in old-growth stands is of prime importance to understand the potential and limits of the climate mitigation role of forests. [ABSTRACT FROM AUTHOR]

Gross primary productivity (GPP) is an important component of the terrestrial carbon cycle in climate change research. The global GPP product derived using Moderate Resolution Imaging Spectroradiometer (MODIS) data is perhaps the most widely used. Unfortunately, many studies have indicated evident error patterns in the MODIS GPP product. One of the main reasons for this is that the applied big‐leaf (BL) MOD17 model cannot properly handle the variable relative contribution of sunlit and shaded leaves to the total canopy‐level GPP. In this study, we developed a model for correcting the errors in the MODIS GPP product by bridging BL and two‐leaf (TL) light use efficiency (LUE) models (CTL‐MOD17). With the available MODIS GPP product, which considers environmental stress factors, the CTL‐MOD17 model only needs to reuse the two inputs of the leaf area index (LAI) and incoming radiation. The CTL‐MOD17 model was calibrated and validated at 153 global FLUXNET eddy covariance (EC) sites. The results indicate that the modeled GPP obtained with the correction model matches better with the EC GPP than the original MODIS GPP product at different time scales, with an improvement of 0.07 in R2 and a reduction in root‐mean‐square error (RMSE) of 117.08 g C m−2 year−1. The improvements are more significant in the green season when the contribution of shaded leaves is larger. In terms of the global spatial pattern, the obvious underestimation in the regions with high LAI and the overestimation in the low LAI regions of the MODIS GPP product is effectively corrected by the CTL‐MOD17 model. This paper not only bridges the BL and TL LUE models, but also provides a new and simple method to obtain accurate GPP through reusing two inputs used in producing the MODIS GPP product. Plain Language Summary: Gross primary productivity (GPP) is crucial for terrestrial carbon cycle study. The Moderate Resolution Imaging Spectroradiometer (MODIS) GPP data is perhaps the most widely used product, but many studies have indicated evident error patterns in it. These errors can be mainly explained by the applied big‐leaf (BL) MOD17 model cannot properly handle the variable relative contribution of sunlit and shaded leaves to the total canopy‐level GPP. As a result, this paper developed a novel and simple model (CTL‐MOD17) to obtain accurate GPP by reusing two inputs data from the MODIS GPP product, based on a two‐leaf (TL) theory. The CTL‐MOD17 model is evaluated at 153 global FLUXNET eddy covariance (EC) sites, and compared with other TL GPP products and models. The results indicate that CTL‐MOD17 can significantly improve the accuracy of MODIS GPP products at different time scales, to be similar to other TL models but with fewer data inputs. The obvious underestimation/overestimation of MODIS GPP in the high/low leaf area index (LAI) regions are all effectively corrected. This study proves the possibility of bridging the BL and TL models for the first time, which can be migrated to other BL products and models. Key Points: A novel product‐based model (CTL‐MOD17) corrects Moderate Resolution Imaging Spectroradiometer (MODIS) gross primary productivity (GPP) product bias, achieving results similar to two‐leaf models with fewer inputsIt is the first time to prove the possibility of bridging the big‐leaf and two‐leaf models, which can be migrated to other big‐leaf GPP products and modelsThe obvious underestimation/overestimation of MODIS GPP in high/low LAI regions are all effectively corrected by the CTL‐MOD17 model [ABSTRACT FROM AUTHOR]

Any scientific career is a mix of planning and stochastic events, often with a fair share of the latter. I illustrate this by the evolution of my own career. Ecosystem studies of food webs under the impact of eutrophication (Master), and carbon cycling in DOC (Dissolved Organic Carbon)-rich lakes (PhD) led me to elemental ratios in organisms and the establishment of ecological stoichiometry. The role of phosphorus (P) in cellular processes again led to research on the evolution and regulation of genome size. As climate came higher on the agenda, it was time to apply the basic research on the C-cycle and climate in a wider context. As natural scientists, we should also engage in even wider contexts, and I have enjoyed discussions and co-operation with philosophers, psychologist, and social scientists. This helps seeing our own work in context. We should also reflect on why we do science. I have always felt that science should also add purpose to life by giving something back to society, and I have devoted much time to outreach, public talks, debates, and writing popular science books. It takes some time, but it is also rewarding and important—perhaps even more so than yet another paper. [ABSTRACT FROM AUTHOR]

Simple Summary: In this paper, the differences in carbon sequestration microbial communities in different wetland types and their main influencing factors were investigated. It was found that the alpha diversity of cbbM carbon-sequestering microorganisms was consistent with the change trend in the total carbon content. Acidithiobacillus was used as a biomarker in lakeside wetlands, and Thiothrix and Thiodictyon were used as biomarkers in marsh wetlands. The diversity of cbbM carbon-fixing microorganisms was primarily influenced by the total nitrogen content, while the community structure was significantly affected by the soil total carbon content. The increase in soil temperature and humidity was conducive to the carbon-sequestering process of Thiomicrospira, Thiomonas, Polaromonas and Acidithiobacillus. The changes in wetland types seriously affected the characteristics of cbbM carbon sequestration in microbial communities, and a warm and humid climate may be conducive to wetland carbon sequestration. Carbon-sequestering microorganisms play an important role in the carbon cycle of wetland ecosystems. However, the response mechanism of carbon-sequestering microbial communities to wetland type changes and their relationship with soil carbon remain unclear. To explore these differences and identify the main influencing factors, this study selected marsh wetlands, river wetlands and lakeside wetlands around Qinghai Lake as research subjects. High-throughput sequencing was employed to analyze the functional gene cbbM of carbon-sequestering microorganisms. The results revealed that the alpha diversity of cbbM carbon-sequestering microorganisms mirrored the trend in total carbon content, with the highest diversity observed in marsh wetlands and the lowest in lakeside wetlands. The dominant bacterial phylum was Proteobacteria, with prevalent genera including Thiothrix, Acidithiobacillus, and Thiodictyon. Acidithiobacillus served as a biomarker in lakeside wetlands, while two other genera were indicative of marsh wetlands. The hierarchical partitioning analysis indicated that the diversity of cbbM carbon-fixing microorganisms was primarily influenced by the total nitrogen content, while the community structure was significantly affected by the soil total carbon content. Moreover, an increased soil temperature and humidity were found to favor the carbon fixation processes of Thiomicrospira, Thiomonas, Polaromonas, and Acidithiobacillus. In summary, changes in wetland types seriously affected the characteristics of cbbM carbon sequestration in microbial communities, and a warm and humid climate may be conducive to wetland carbon sequestration. [ABSTRACT FROM AUTHOR]

Tropical peatlands are crucial ecosystems, storing vast carbon reserves and supporting rich biodiversity. Despite covering a small land area, they play significant roles in global carbon cycling and climate regulation. However, these ecosystems face escalating threats from human activities, including agricultural expansion and peatland drainage. This paper provides a concise overview of tropical peatlands, focusing on their distribution, characteristics, and ecological importance in Southeast Asia, Africa, and South America. It highlights the diverse vegetation communities and notable animal species found in peat swamp forests, underscoring their conservation value. Peatland degradation leads to increased greenhouse gas emissions, land subsidence, and loss of traditional livelihoods for local communities. Addressing these challenges requires integrated approaches, including conservation efforts to protect and restore intact peat swamp forests, sustainable land-use practices, and policy interventions to regulate land management. Research collaboration between scientists, policymakers, and local communities is essential for developing evidence-based conservation strategies. By prioritizing the preservation of tropical peatlands, we can mitigate climate change impacts, conserve biodiversity, and safeguard the well-being of local communities. [ABSTRACT FROM AUTHOR]

China's rapid economic development has consumed a large amount of energy, causing serious environmental pollution problems and contributing to global warming. This paper calculates the carbon emissions of the fishery sector and uses Random Forest (RF) for the first time to analyze the influencing factors of future carbon emissions. The results of the study show that increasing carbon sinks dominate the reduction of carbon emissions in the fisheries sector. Carbon sinks will continue to dominate emission reductions in the fisheries sector if positive mitigation measures are taken. Continuing the current pattern of fisheries development, the fishery population has a significant impact on future carbon emissions. Per capita incomes under a crude economic model will inhibit carbon emission reductions. The research results can provide guidance for the development of fishery low carbon economy and the formulation of emission reduction policies. [ABSTRACT FROM AUTHOR]

This paper aims to update our understanding of the carbon cycle in the Himalayas, the most intense collisional orogeny globally, by providing new insight into its impact on Cenozoic climate cooling through the use of isotopic variations in both organic and inorganic carbon and an isotopic mass balance model. Our results from 20 selected hot springs show that the relative contributions of dissolved carbon from the mantle, metamorphic decarbonization, aqueous dissolution, and soil organic matter are approximately 2%, 82%, 6%, and 10%, respectively. Approximately 87% ± 5% of CO2 generated in the deep crust precipitates as calcite, while approximately 5.5% ± 1% of this carbon is converted to biomass through microbial chemosynthesis at depths less than 2 km. Our random forests approach yielded a metamorphic carbon flux from the entire Himalayan orogenic belt of approximately 2.7 ∼ 4.5 × 1012 mol/yr. The minor CO2 released into the atmosphere (2.5 ∼ 4.2 × 1011 mol/yr) is comparable to the carbon consumption driven by Himalayan weathering. This paper provides new insights into deep carbon cycling, notably that approximately 93% of deeply sourced carbon is trapped in the shallow crust, rendering orogenic processes carbon neutral and possibly acting as one of the major triggers of long‐term climate cooling in the Cenozoic. Plain Language Summary: Large‐scale deep metamorphic decarbonization and CO2 release into the atmosphere during continental collision orogenesis worldwide have had significant impacts on Cenozoic global climate change. However, the carbon sources and sinks and the mechanisms underlying their impacts on climate change are not fully understood. This paper reports the chemistry of aqueous solutions, carbon isotopic compositions of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC), and helium and carbon isotopic compositions of free gases from hot springs in southern Tibet. The carbon isotope fractionation model between gas and aqueous solutions revealed that the carbon released from depth underwent six different stages. Based on the random forests machine learning algorithm, we estimated the metamorphic carbon flux across the Himalayan orogenic belt. Furthermore, only a small fraction (7%) of deep carbon is eventually released into the atmosphere, and this volume is the same magnitude as the amount of carbon absorbed by silicate weathering on the Tibetan Plateau. This paper emphasizes that the carbon sequestration process in the upper crust may have resulted in nearly carbon‐neutral geological bodies in the Himalayan orogenic belt, thus playing a critical role in Cenozoic climate cooling. Key Points: Approximately 87% of deeply sourced carbon precipitates as calcite, while approximately 5.5% is sequestered as biomass in the shallow crustThe carbon flux across the Himalayan orogenic belt was estimated by the random forests approachCrustal thickening has attenuated long‐term deep carbon emissions from the Himalayas [ABSTRACT FROM AUTHOR]

The atmospheric carbon dioxide (CO2) concentration has been increasing rapidly since the Industrial Revolution, which has led to unequivocal global warming and crucial environmental change. It is extremely important to investigate the interactions among atmospheric CO2, the physical climate system, and the carbon cycle of the underlying surface for a better understanding of the Earth system. Earth system models are widely used to investigate these interactions via coupled carbon-climate simulations. The Chinese Academy of Sciences Earth System Model version 2 (CAS-ESM2.0) has successfully fixed a two-way coupling of atmospheric CO2 with the climate and carbon cycle on land and in the ocean. Using CAS-ESM2.0, we conducted a coupled carbon-climate simulation by following the CMIP6 proposal of a historical emissions-driven experiment. This paper examines the modeled CO2 by comparison with observed CO2 at the sites of Mauna Loa and Barrow, and the Greenhouse Gases Observing Satellite (GOSAT) CO2 product. The results showed that CAS-ESM2.0 agrees very well with observations in reproducing the increasing trend of annual CO2 during the period 1850–2014, and in capturing the seasonal cycle of CO2 at the two baseline sites, as well as over northern high latitudes. These agreements illustrate a good ability of CAS-ESM2.0 in simulating carbon-climate interactions, even though uncertainties remain in the processes involved. This paper reports an important stage of the development of CAS-ESM with the coupling of carbon and climate, which will provide significant scientific support for climate research and China's goal of carbon neutrality. [ABSTRACT FROM AUTHOR]

Climate change is a pressing global concern with far-reaching implications and its impact on soil properties is a critical aspect that warrants comprehensive investigation. This abstract delves into the multifaceted effects of climate change on soil, highlighting the intricate relationships between climate patterns and soil characteristics. Rising temperatures associated with climate change contribute to increased evaporation rates, leading to changes in soil moisture levels. These alterations can influence soil structure, affecting porosity, compaction and water retention capacity. Additionally, shifting precipitation patterns may result in changes to soil erosion and sedimentation rates, impacting nutrient cycling and the overall fertility of the soil. The increase in extreme weather events, such as floods and droughts, intensifies soil erosion and nutrient loss. Changes in temperature and precipitation also influence microbial activity and diversity in the soil, impacting crucial processes like decomposition and nutrient mineralization. These alterations in microbial communities can further cascade into shifts in soil organic matter content and nutrient availability. Furthermore, the interaction between climate change and soil properties extends to the realm of soil carbon sequestration. Altered conditions may affect the balance between carbon inputs and outputs, influencing the capacity of soils to act as carbon sinks. Understanding these complex dynamics is imperative for sustainable land management practices and developing strategies to mitigate the adverse effects of climate change on soil properties. This review paper throws light on the complex interplay between climate change and soil properties underscoring the need for interdisciplinary research to unravel the intricacies of this relationship. Such knowledge is indispensable for formulating effective adaptation and mitigation strategies to safeguard soil health, ensuring the resilience of ecosystems and global food security in the face of ongoing climate challenges. [ABSTRACT FROM AUTHOR]

Peatlands are major natural carbon pool in terrestrial ecosystems globally and are essential to a variety of fields, including global ecology, hydrology, and ecosystem services. Under the context of climate change, the management and conservation of peatlands has become a topic of international concern. Nevertheless, few studies have yet systematized the overall international dynamics of existing peatland research. In this study, based on an approach integrating bibliometrics and a literature review, we systematically analyzed peatland research from a literature perspective. Alongside traditional bibliometric analyses (e.g., number of publications, research impact, and hot areas), recent top keywords in peatland research were found, including 'oil palm', 'tropical peatland', 'permafrost', and so on. Furthermore, six hot topics of peatland research were identified: (1) peatland development and the impacts and degradations, (2) the history of peatland development and factors of formation, (3) chemical element contaminants in peatlands, (4) tropical peatlands, (5) peat adsorption and its humic acids, and (6) the influence of peatland conservation on the ecosystem. In addition, this review found that the adverse consequences of peatland degradation in the context of climate change merit greater attention, that peatland-mapping techniques suitable for all regions are lacking, that a unified global assessment of carbon stocks in peatlands urgently needs to be established, spanning all countries, and that a reliable system for assessing peatland-ecosystem services needs to be implemented expeditiously. In this study, we argued that enhanced integration in research will bridge knowledge gaps and facilitate the systematic synthesis of peatlands as complex systems, which is an imperative need. [ABSTRACT FROM AUTHOR]

Increasing global temperatures due to high atmospheric carbon dioxide (CO2) concentrations may cause an imbalance in the carbon circulation on earth. It has been reported that CO2 emissions from natural soils in all terrestrial areas on Earth account for about 25% of atmospheric CO2 emissions in the global carbon cycle. A tendency is well known that the higher the soil temperature with the higher the metabolic activity of microorganisms in the soil. Furthermore, since the global soil CO2 emissions are huge amount that approximately seven times the total atmospheric CO2 emissions from human origin, it is necessary to investigate the increasing rate of soil CO2 emission rate per unit area and unit time on a global scale (global soil CO2 efflux) that is affected by soil temperature rise due to global warming expected in the coming decades. In this paper, we modeled soil CO2 efflux vs. diurnal and seasonal variation in soil temperature at a measurement point using a formula that is an exponential function of soil temperature and then evaluated the effect of increasing average soil temperature due to surface air temperature rise by global warming. We have proposed a method to analogically evaluate the potential of increasing the rate of soil CO2 efflux against a change of 1°C in soil temperature based on the model equation. The power index b (°C-1) just indicates the potential of increasing the rate of soil CO2 efflux to soil temperature rise in any land area with different soil temperatures on earth. Finally, the values of b were obtained from the published literature with field measurement data at 71 locations in 10 countries including our data measured at the Ito campus, Kyushu University. The average rate of potential increase in soil CO2 efflux is 0.10°C-1 regardless of vegetation, annual rainfall (precipitation), soil type, and soil components (carbon and nitrogen content). In conclusion, assuming the average soil temperature rises by 1°C and ignoring any effects reducing soil CO2 reduction due to global warming, the potential increase in annual global soil CO2 efflux is roughly estimated at 22 billion tons-CO2/year. [ABSTRACT FROM AUTHOR]

Straw is an important source of organic fertilizer for soil enrichment, however, the effects of different nitrogen(N) application rates and depths on straw decomposition microorganisms and carbon and nitrogen cycling under full straw return conditions in cool regions of Northeast China are not clear at this stage. In this paper, we applied macro-genome sequencing technology to investigate the effects of different N application rates (110 kg hm−2, 120 kg hm−2, 130 kg hm−2, 140 kg hm−2, 150 kg hm−2) and depths (0–15 cm, 15–30 cm) on straw decomposing microorganisms and N cycling in paddy fields in the cool zone of Northeast China. The results showed that (1) about 150 functional genes are involved in the carbon cycle process of degradation during the degradation of returned straw, of which the largest number of functional genes are involved in the methane production pathway, about 42, the highest abundance of functional genes involved in the citric acid cycle pathway. There are 22 kinds of functional genes involved in the nitrogen cycle degradation process, among which there are more kinds involved in nitrogen fixation, with 4 kinds. (2) High nitrogen application (150 kg hm−2) inhibited the carbon and nitrogen conversion processes, and the abundance of straw-degrading microorganisms and nitrogen-cycling functional genes was relatively high at a nitrogen application rate of 130 kg hm−2. (3) Depth-dependent heterogeneity of the microbial community was reduced throughout the vertical space. At 71 days of straw return, the nitrogen cycling function decreased and some carbon functional genes showed an increasing trend with the increase of straw return depth. The nitrogen cycle function decreased with the increase of straw returning depth. The microbial community structure was best and the abundance of functional genes involved in the nitrogen cycling process was higher under the conditions of 0–15 cm of returning depth and 130 kg hm−2 of nitrogen application. [ABSTRACT FROM AUTHOR]

Disposable consumer electronics become electronic waste at the end of their life, which can cause serious environmental pollution if discarded in the ground. Here, we have developed an all-wood-based flexible electronic device. The substrate is used to prepare self-densification wood-derived paper (SWP) at room temperature through the natural balsa wood (NW) self-densification process. Chemical treatment removed lignin and hemicellulose from NW, and the cell wall structure collapsed under the action of elastic capillary force generated by water evaporation. The hydrogen bonds between the cellulose fibers are further strengthened, and the arrangement of the cellulose fibers is maintained. The obtained SWP exhibits an excellent tensile strength of 229.4 ± 10.4 MPa in the fiber direction, which is 8.3–8.6 times (27.1 ± 1.7 MPa) and 4.2–4.8 times (51.2 ± 5.6 MPa) higher than NW and cellulose paper, respectively, and higher than some commercial plastics. In addition, it also exhibits excellent wetting performance and a certain degree of transparency. Finally, conductive wood carbon ink prepared from carbonized NW can be directly written on SWP using a Chinese brush to obtain customized patterns. We have demonstrated the application of an all-wood-based flexible electronic device in flexible sensors that can stably monitor finger movements. This newly developed all-wood-based composite can return to the carbon cycle of nature after its service life, providing a new way to replace traditional electronic products. [ABSTRACT FROM AUTHOR]

As the vegetation in the Arctic changes, tundra ecosystems along the southern border of the Arctic are becoming greener and gradually giving way to boreal ecosystems. This change is affecting local populations, wildlife, energy exchange processes between environmental compartments, and the carbon cycle. To understand the progression and the implications of this change in vegetation, satellite measurements and surface models can be employed. However, in situ observational data are required to validate these measurements and models. This paper presents observational data from two nearby sites in the forest–tundra ecotone in the Tasiapik Valley near Umiujaq in Northern Quebec, Canada. One site is on a mixture of lichen and shrub tundra. The associated data set comprises 9 years of meteorological, soil and snow data as well as 3 years of eddy covariance data. The other site, 850 m away, features vegetation consisting mostly of tall shrubs and black spruce. For that location, 6 years of meteorological, soil and snow data are available. In addition to the data from the automated stations, profiles of snow density and specific surface area were collected during field campaigns. The data are available at 10.1594/PANGAEA.964743 (Domine et al., 2024). [ABSTRACT FROM AUTHOR]

The response of evapotranspiration to anthropogenic warming is of critical importance for the water and carbon cycle. Contradictory conclusions about evapotranspiration changes are caused primarily by their brevity in time and sparsity in space, as well as the strong influence of internal variability. Here, we present the first gridded reconstruction of the summer (June, July, and August) vapor pressure deficit (VPD) for the past 4 centuries at the European level. This gridded reconstruction is based on 26 European tree ring oxygen isotope records and is obtained using a random forest approach. According to validation scores obtained with the Nash–Sutcliffe model efficiency, our reconstruction is robust over large parts of Europe since 1600, in particular for the westernmost and northernmost regions, where most tree ring records are located. Based on our reconstruction, we show that from the mid-1700s a trend towards higher summer VPD occurred in central Europe and the Mediterranean region that is related to a simultaneous increase in temperature and decrease in precipitation. This increasing summer VPD trend continues throughout the observational period and in recent times. Moreover, our summer VPD reconstruction helps to visualize the local and regional impacts of the current climate change, as well as to minimize statistical uncertainties of historical VPD variability. This paper provides also new insights into the relationship between summer VPD and large-scale atmospheric circulation, and we show that summer VPD has two preferred modes of variability, namely a NW–SE dipole-like mode and a N–S dipole-like mode. Furthermore, the interdisciplinary use of the data should be emphasized, as summer VPD is a crucial parameter for many climatological feedback processes in the Earth's surface system. The reconstructed summer VPD gridded data over the last 400 years are available at the following link: 10.5281/zenodo.5958836 (Balting et al., 2022). [ABSTRACT FROM AUTHOR]