Carbon Flow Research Articles

Carbon metabolism in "production-living-ecological" space in urban agglomeration based on land use change.

To grasp the impact of carbon metabolism on the evolution of "production-living-ecological" (PLE) space due to land usechange in the Changsha-Zhuzhou-Xiangtan (CZT) urban agglomeration, this study delves into the temporal and spatial distribution of PLE space carbon metabolism by constructing a carbon flow model. We evaluate the influence of positive and negative carbon flows on carbon metabolism using ecological network analysis and utility assessment. Furthermore, we delve into the driving factors behind carbon metabolism through redundancy analysis (RDA). The findings of this study included mainly the following aspects. (1) From 2000 to 2020, the net carbon flow in the CZT urban agglomeration consistently remained negative, with the primary source of negative carbon flow being the transition from ecological space to production space. (2) Within the ecological utility network, the dominant ecological relationship shifted from a period of control and exploitation relationship (counted for 61.91%) between 2000 and 2005 to one of competition relationship that counted for 83.33% in 2005-2010, 47.62% in 2010-2015, and 66.67% in 2015-2020. Mutualism relationship, present in the 2000-2005 period, completely disappeared in subsequent years. (3) The value of the utility function M was 0.88, 0.36, 0.48, and 0.40 in four stages (all less than 1), which meant that PLE space evolution on regional carbon metabolism was negative. (4) The key drivers influencing carbon metabolism in PLE space were mainly Change in the Comprehensive Land Use Index (CL), Change in the Proportion of Manufacturing Land (CM), Change in the Proportion of Forestland (CF), and Change in the Proportion of Cultivated Land (CC). Carbon metabolism holds a critical role in the urban material and energy cycle. Studying carbon metabolism within PLE space carries great importance for regional carbon cycling, carbon emission and sequestration, efforts to mitigate climate change, and the maintenance of regional sustainable development.

Interspecific, ontogenetic and temporal variations in stable isotopes of small tuna species in the northeast Atlantic Ocean

ABSTRACT In order to study the trophic level of small tuna species and their contribution to the carbon flow in pelagic food webs, an analysis of carbon and nitrogen stable isotopes was carried out. The investigation was focused on four small tuna species (Auxis rochei, Auxis thazard, Euthynnus alletteratus and Sarda sarda) commonly harvested in the northeast Atlantic Ocean. The isotope analysis showed how the results for S. sarda are different from the rest of the species analysed, with a higher trophic level, similar to other major tuna species. The greatest niche overlap in δ13C and δ15N occurs among A. rochei, A. thazard and E. alletteratus. Auxis rochei and E. alletteratus showed a size-dependent variability in δ15N, and in δ13C for S. sarda. The small tuna S. sarda exhibits the highest migration rates among various geographical areas in comparison to other small pelagic tunas, and the seasonal variability of isotope values in the area studied can be attributed to the incorporation of larger individuals with a higher lipid content. The results of this work provide new information on the ecological role played by small tuna in food webs, which is more complex and varied than currently thought. This knowledge is essential for a more effective management of fisheries.

Applications of Information Technology in Building Carbon Flow

The construction industry, as one of the three major carbon emission (CE) industries, accounts for about 39% of the global CE. Thus, approaches for energy saving and emission reduction (ES/ER) cannot be delayed. With the advent of the Industry 4.0 era, information technology (IT) is used to investigate CE in the construction industry, which provides great convenience for measuring and calculating building carbon emissions (BCE) and proposing effective ES/ER measures. However, limited studies have provided a holistic overview of the application of IT in BCE. To fill this gap, this study searched related articles and screened 170 relevant papers. Based on the characteristics of the literature, building carbon flow (BCF) was defined. Based on scientometric analysis and network mapping analysis, combined with quantitative and qualitative analysis methods, the functions, advantages, and limitations of IT in each stage of BCF research were reviewed. Finally, the research trends and future research directions of IT in the BCF were discussed. Specifically, the building information model technology penetrates the whole process of BCF research, deep learning and artificial intelligence have great potential in BCF research, and multi-information technology integration will become the focus of subsequent research in the construction industry.

Which sectors should be covered by the EU Carbon Border Adjustment Mechanism?

The European Union (EU) is developing the Carbon Border Adjustment Mechanism (CBAM) to address carbon leakage in international trade. However, the EU has paid inadequate attention to input‒output linkages, specifically those in the steel, aluminum, and fertiliser industries. This study aims to identify priority sectors eligible for initial regulation within the emissions-intensive trade-exposed (EITE) industries based on input–output linkages and compare its impacts with the current CBAM sector coverage. This study constructs a Global Production Network (GPN) and Carbon Flow Network (CFN) to present the input trade and embodied carbon flows for the EITE industries. This study highlights the role of the EITE industries as influential nodes in the production network and how the EITE industries in the EU contribute to carbon emissions. To improve the economy and political acceptability, CABM should cover four priority sectors with low economic impacts but a crucial role in reducing emissions, such as plastics, phosphorus fertiliser, aluminum, and copper industry.

Insights into the Peroxide-Bicyclic Intermediate Pathway of Aromatic Photooxidation: Experimental Yields and NOx-Dependency of Ring-Opening and Ring-Retaining Products.

Aromatic hydrocarbons are important contributors to the formation of ozone and secondary organic aerosols in urban environments. The different parallel pathways in aromatic oxidation, however, remain inadequately understood. Here, we investigated the production yields and chemical distributions of gas-phase tracer products during the photooxidation of alkylbenzenes at atmospheric OH levels with NOx present using high-resolution mass spectrometers. The peroxide-bicyclic intermediate pathway emerged as the major pathway in aromatic oxidation, accounting for 52.1 ± 12.6%, 66.1 ± 16.6%, and 81.4 ± 24.3% of the total OH oxidation of toluene, m-xylene, and 1,3,5-trimethylbenzene, respectively. Notably, the yields of bicyclic nitrates produced from the reactions of bicyclic peroxy radicals (BPRs) with NO were considerably lower (3-5 times) than what the current mechanism predicted. Alongside traditional ring-opening products formed through the bicyclic pathway (dicarbonyls and furanones), we identified a significant proportion of carbonyl olefinic acids generated via the 1,5-aldehydic H-shift occurring in subsequent reactions of BPRs + NO, contributing 4-7% of the carbon flow in aromatic oxidation. Moreover, the observed NOx-dependencies of ring-opening and ring-retaining product yields provide insights into the competitive nature of reactions involving BPRs with NO, HO2, and RO2, which determine the refined product distributions and offer an explanation for the discrepancies between the experimental and model-based results.

Bacterial Inoculation and Extracts of Opuntia Rackets or Marine Algae Trigger Distinct Proline Balances in Tomato Salt Stress Alleviation

High salt levels in soil can severely limit plant development and diminish the positive effect of plant-growth-promoting rhizobacteria (PGPR). However, extracts of organisms adapted to high salinity, such as Opuntia ficus-indica (OFI) and Enteromorpha intestinalis (EI), can restore the growth of PGPR. Therefore, we used OFI or EI extracts and their combination with the PGPR Achromobacter xylosoxidans BOA4 to evaluate salt stress relief in tomato (Solanum lycopersicum). The experimental setup consisted of a plant pot trial under greenhouse conditions with 12 treatments: control, irrigation with OFI extract; EI extract; BOA4-inoculated plus OFI extract and BOA4-inoculated plus EI extract under no salinity or salinity conditions (150 mM NaCl). The percentage of germination, and plant’s fresh and dry weight were registered 30 and 46 days after sowing. At 46 days, the ratio between proline and glutamic acid concentration (PR/GA) was determined, expecting high PR/GA ratios in plants more responsive to salt stress since proline is an osmolyte mainly synthesized from glutamate. The results showed that 52% of the control seeds under salt stress germinated, a figure that was increased to 92% in OFI-treated seeds. Tomato plants were shown to be very sensitive to salt stress since the dry weight was ca. one fourth that of the plants grown without salinity. However, EI or BOA4 plus EI stimulated plant biomass by ca. 3 times compared to the control with salt, restoring plant biomass to values comparable to those of control plants grown without salinity. The joint treatments with BOA4 and EI or OFI caused distinct PR/GA levels in plant tissues. An inverse relationship between the sum of relative shoot proline and glutamic acid contents and shoot biomass accumulation was observed, namely in treatments accumulating more biomass under no salinity and salinity conditions. This indicates that the proline/glutamate pathway represents a carbon sink that is needed to fight stress and is competing with the carbon flow used for growth.

Metabolic signatures of thymomas: potential biomarkers and treatment targets.

A study of tumour metabolic reprogramming has revealed disease biomarkers and avenues for therapeutic intervention. Metabolic reprogramming in thymoma is currently understudied and largely unknown. This study utilized metabolomics and isotope tracing with 13C-glucose to metabolically investigate thymomas, adjacent thymic tissue and benign thymic lesions. From 2017 to 2021, 20 patients with a suspected thymoma were recruited to this prospective Institutional Review Board approved clinical trial. At the time of surgery, 11 patients were infused with 13C-glucose, a stable, non-radioactive tracer which reports the flow of carbon through metabolic pathways. Samples were analysed by mass spectrometry to measure the abundance of >200 metabolites.13C enrichment was measured in patients who received 13C-glucose infusions. Histological analysis showed that 9 patients had thymomas of diverse subtypes and 11 patients had benign cysts. In our metabolomic analysis, thymomas could be distinguished from both adjacent thymus tissue and benign lesions by metabolite abundances. Metabolites in pyrimidine biosynthesis and glycerophospholipid metabolism were differentially expressed across these tissues.13C-glucose infusions revealed differential labelling patterns in thymoma compared to benign cysts and normal thymus tissue. The lactate/3PG labelling ratio, a metabolic marker in aggressive lung tumours correlated with lactate uptake, was increased in thymomas (1.579) compared to normal thymus (0.945) and benign masses (0.807) (thymic tissue versus tumour P = 0.021, tumour versus benign P = 0.013). We report metabolic biomarkers, including differential 13C labelling of metabolites from central metabolism, that distinguish thymomas from benign tissues. Altered glucose and lactate metabolism warrant further investigation and may provide novel therapeutic targets for thymoma.

Typology of planktonic food webs and associated emerging properties as indicators of the ecological status of a permanently disturbed Gulf of Gabès

This study highlights the importance of coupling the typology of planktonic food webs and their emerging properties to better describe the ecological status of an ecosystem under permanent disturbance mainly caused by phosphate industry. Linear inverse models were built to describe four stations under various levels of nutrient pressure, using the Markov Chain Monte Carlo method to estimate known and unknown carbon flows, later used to calculate food web typology ratios. Ecological network analysis (ENA) was used to describe the structural and functional properties of each food web. Based on the food web typology ratios, three planktonic trophic pathways (PTP) with different functional indices were distinguished according to nutrient stress. The microbial food web dominated in the least nutrient-rich environment. It mainly relied on phytoplankton production (picophytoplankton <2 μm) that was mainly transferred by the high microbivory of protozooplankton. In contrast, the herbivorous food web developed in the most nutrient-rich environment, where biogenic carbon was mainly produced by large phytoplankton (microphytoplankton >10 μm) and channeled to higher trophic levels by herbivorous protozooplankton and metazooplankton. In the other two stations – moderately nutrient-rich systems – the PTP acted as a multivorous food web. Phytoplankton (small and large size fractions) and non-living components (detritus and dissolved organic carbon) played a significant role in carbon production, and competed with protozooplankton and metazooplankton for its transport. ENA indices revealed that the herbivorous food web, with the highest total system throughput and lowest relative Ascendency and cycling, was the most active but the least organized and stable system. In contrast, the microbial food web, with the lowest total system flux and highest Ascendency, was least active but more organized than the herbivorous food web. The multivorous food web displayed the most recycling and most organized system, with high values of the detritivory-to-herbivory ratio, cycling and Ascendency. In addition to ENA indices, which are considered effective tools for studying the structural and functional properties of food webs, marine ecosystem management efforts heavily focus on using the “marine food web” as a descriptor of the system's ecological status. However, we suggest that the combination of food web typology and ecological indices could be used as an effective tool for the management and assessment of ecosystem health wherever possible, as well as for the study of anthropogenic pressures.

Emerging sensing, imaging, and computational technologies to scale nano-to macroscale rhizosphere dynamics – Review and research perspectives

The soil region influenced by plant roots, i.e., the rhizosphere, is one of the most complex biological habitats on Earth and significantly impacts global carbon flow and transformation. Understanding the structure and function of the rhizosphere is critically important for maintaining sustainable plant ecosystem services, designing engineered ecosystems for long-term soil carbon storage, and mitigating the effects of climate change. However, studying the biological and ecological processes and interactions in the rhizosphere requires advanced integrated technologies capable of decoding such a complex system at different scales. Here, we review how emerging approaches in sensing, imaging, and computational modeling can advance our understanding of the complex rhizosphere system. Particularly, we provide our perspectives and discuss future directions in developing in situ rhizosphere sensing technologies that could potentially correlate local-scale interactions to ecosystem scale impacts. We first review integrated multimodal imaging techniques for tracking inorganic elements and organic carbon flow at nano-to microscale in the rhizosphere, followed by a discussion on the use of synthetic soil and plant habitats that bridge laboratory-to-field studies on the rhizosphere processes. We then describe applications of genetically encoded biosensors in monitoring nutrient and chemical exchanges in the rhizosphere, and the novel nanotechnology-mediated delivery approaches for introducing biosensors into the root tissues. Next, we review the recent progress and express our vision on field-deployable sensing technologies such as planar optodes for quantifying the distribution of chemical and analyte gradients in the rhizosphere under field conditions. Moreover, we provide perspectives on the challenges of linking complex rhizosphere interactions to ecosystem sensing for detecting biological traits across scales, which arguably requires using the best-available model predictions including the model-experiment and image-based modeling approaches. Experimental platforms relevant to field conditions like SMART (Sensors at Mesoscales with Advanced Remote Telemetry) soils testbed, coupled with ecosystem sensing and predictive models, can be effective tools to explore coupled ecosystem behavior and responses to environmental perturbations. Finally, we envision that with the advent of novel high-resolution imaging capabilities spanning from nano-to macroscale, and remote biosensing technologies, combined with advanced computational models, future studies will lead to detection and upscaling of rhizosphere processes toward ecosystem and global predictions.

Stable-isotope probing highlights the active microbes associated with carbon flow under different cultivation conditions: Rhizosphere soil versus bulk soil and upland soil versus paddy soil

Plant carbon (C) released into the rhizosphere will ultimately impact the bulk soil, varying with soil water status. However, the microbial communities involved, and how they vary between rhizosphere and bulk soil, and under varying water regimes, are little understood. Here, within a continuous 13CO2 labeling chamber, a rhizobox-like system was utilized to cultivate ryegrass (upland) and rice (paddy) to identify the root-derived C flow and associated active microbes. The 15N-labeled fertilizer was used to measure the N flow from the soils and plants. The 13C labeled soil organic C (13C-SOC) values of upland soil were greater than those of paddy soil. There was a reduction in 13C-SOC values from the rhizosphere to the bulk soils, but the total 15N labeled N (15N-TN) values exhibited an increase trend from this direction. The isotopic enrichment of PLFAs and DNA sequencing results indicated that the bacterial and fungal abundance and diversity exhibited augmentation in the rhizosphere soil under both cultures compared with the bulk soils. Bacteria played a much more important role than fungi in the C flow in the paddy soil. However, fungi dominantly contributed to this flow in the upland soils. Our findings revealed a vital role of Ascomycota fungi (especially Talaromyces) and Actinobacteria bacteria (Actinomycetales and Gaiellales) in contributing to the assimilation of root-derived C for the upland and paddy soils, respectively.

Imagining circular carbon: A mitigation (deterrence) strategy for the petrochemical industry

Petrochemical producers both rely upon and generate some of the most problematic substances in the current age of socioecological crisis: fossil fuels and plastics. With mounting calls to cap fossil fuel extraction as well as plastics production, the industry appears to be caught between a rock and a hard place. Nonetheless, betting on continuously increasing global plastic demand, petrochemical production is expanding significantly. This predicament raises the question of how the industry attempts to square increasing petrochemical production with the need to address environmental issues. In recent years, leading actors in and around the industry have promoted notions of carbon circularity as a desirable mitigation strategy. In this paper, we examine this strategy, using discourse analysis to uncover what we refer to as the imaginary of circular carbon. We highlight how the circular carbon imaginary risks delaying climate mitigation by rendering alternative mitigation pathways undesirable. It does so by reconciling increased production, carbon neutrality, and circular economy in a vision of a circular carbon economy, framing the climate crisis as an issue of carbon management. In the circular carbon economy, carbon dioxide, petrochemicals, and plastics all fit as mere flows of carbon. The circular carbon imaginary thereby helps future-proof the petrochemical industry in legitimizing its carbon-intensive practises essential to the fossil world order and the plastic crisis.

A region-based low-carbon operation analysis method for integrated electricity-hydrogen-gas systems

A region-based low-carbon operation analysis method for integrated electricity‑hydrogen-gas systems (IEHGSs) is proposed in this paper. The committed carbon emission operation region (CCE_OR) and the economic CCE_OR (ECCE_OR) are proposed to evaluate the low-carbon feasible space (LCFS) from the low-carbon, secure, and economic perspectives, which provides powerful tools for the low-carbon operation analyses of IEHGSs. Firstly, a coordinated mechanism of carbon flow and hydrogen flow is developed to excavate the low-carbon operation potential of IEHGSs. Then, based on the distributionally robust chance-constrained approach, the concepts and models of CCE_OR and ECCE_OR are defined and formulated considering uncertainties and hydrogen merits. Furthermore, a region model reformulation method is proposed to reformulate the uncertain and non-convex CCE_OR and ECCE_OR models into the deterministic and mixed-integer linear region models. The geometric properties of CCE_OR and ECCE_OR are both theoretically proven, which are the union set of finite convex and bounded polytopes. The united region solution methodology considering the geometric properties of CCE_OR and ECCE_OR is presented to effectively characterize CCE_OR and ECCE_OR. Finally, the numerical results on two test systems verify the effectiveness and applicability of the proposed methods. Simulation results indicate that the proposed methods can improve the LCFS, characterize visual coupling relationships between LCFS and observation variables, and provide comprehensive low-carbon operation information of operation points.

Leguminous crop restores the carbon flow attenuation from nitrogen loading within soil nematode food web in a Camellia oleifera plantation

Excessive nitrogen (N) loading poses a substantial risk to soil biodiversity and disrupts carbon (C) flows within the soil food web. Intercropping with legumes is often considered a sustainable way to maintain soil N availability and mitigate the associated detrimental effects. However, it remains unclear whether and how legume crops restore energetic attenuation caused by N loading within the soil food web. Here, we conducted a two-year field experiment using randomized block design in a subtropic Camellia oleifera plantation with high wet N deposition. We examined the effects of applying N fertilizers at normal or half levels (168 or 84 kg N ha−1yr−1) and intercropping legumes (Arachis hypogaea or Cassia tora) on the soil nematode food web. We observed that N fertilization suppressed the majority of nematode trophic groups, weakened the stability of food web structure, and diminished the C flows across the bacterial and fungal energy channels. Conversely, intercropping with legumes (particularly with C. tora) bolstered the densities of bacterivore and fungivore nematodes. This enhancement facilitated interactions within the soil micro-food web, and subsequently augmented the C flows within their respective channels. Model predictions suggested that the detrimental effects of N fertilizers on the nematode food web are primarily linked to decreased soil pH resulting from soil N accumulation. Notably, higher soil organic C was found to mitigate these effects. Furthermore, N-enriched legume substrates played a beneficial role in stimulating soil microbial activities and facilitating C flows through bottom-up control. Our findings emphasize the positive impacts of legume crops on mitigating soil biodiversity loss and restoring energetic attenuation within soil food web under N-saturated soil conditions. These findings provide valuable insights for agroforestry management practices aimed at sustaining soil health and ecosystem resilience.

Controlling carbon nanostructure synthesis in thermal plasma jet: Correlation of process parameters, plasma characteristics, and product morphology

Thermal plasma has emerged as an effective approach for producing carbon nanostructures without the need for specific catalysts nor substrates. While efforts have focused on the effect of process parameters such as reaction pressure, input power or carbon source, the intricate role and relationship with plasma characteristics like density and temperature are often overlooked due to the complexity of the environment. This study addresses this gap by establishing a correlation between process parameters, plasma characteristics, and product morphology, essential for controlling the growth of carbon nanostructures. We explored the impact of carbon precursor type (CH4 and C2H2), hydrogen, pressure, and flow rate on nanostructure formation. Using in situ optical emission spectroscopy (OES), we mapped the distribution of both temperature and dicarbon molecule (C2) density within the plasma jet. We demonstrate that the growth of low-density nanostructures, such as carbon nanohorns (CNHs), is favoured at dilute C2 local densities and high temperatures, while denser nanostructures, such as onion-like polyhedral graphitic nanocapsules (GNCs), are favoured at higher C2 densities and lower temperatures. The carbon density can be controlled by the flow rate and the pressure, which in turn significantly influence the nanostructure morphology, evolving from graphene nanoflakes (GNFs) to GNCs as either parameter increases. Increasing the H/C ratio from 1 to 8 resulted in a morphological transition from CNHs to GNFs. During the synthesis, the plasma jet temperature surpassed 3000 K, with crystalline growth occurring 50–100 mm below the nozzle.

Decarbonization potential collaborated with source industries for China's iron and steel industry towards carbon neutrality

Towards the target of carbon neutrality, the need for deep decarbonization in iron and steel industry is increasingly recognized. Existing studies rarely mention the effects of collaboration with its source industries for carbon emission reduction in ISI. Furthermore, the fundamental laws of CO2 emission reduction capacity with cost change of source substitutions for various steel production routes under market economics are unclear. To avoid the blind substitution of clean sources for meeting the urgent requirements for decarbonization in China's steel industry, which may result in increased carbon emissions and uneconomical carbon reduction from a lifecycle perspective. This paper integrates the production and utilization processes of source resources into the steel production process, establishes coupling models of carbon and value flows for four main types of steel production routes, and aims to quantitatively analyze the specific CO2 emission reduction potential and costs. Three economic market development scenarios from 2021 to 2060 are set, and the marginal carbon prices of various source substitutions are determined. Subsequently, decarbonization pathways with the goal of minimizing production costs are developed. Finally. The future resource demand and the carbon emission reduction contributions of source industries collaborated are predicted. The results show that (1) about 81.7–89.9 % of CO2 emissions could be reduced in the scenarios; (2) the demands of electric power and hydrogen energy will reach 54.48–511.90 BkWh and 7.47–10.31 Gt in 2060, respectively; and (3) collaboration with source industries could make 18.3–18.3% of CO2 emission reduction contributions. All in all, this study could provide scientific support for the low-carbon transformation of China's steel industry.

Physiological and molecular bases of the boron deficiency response in tomatoes

Abstract Boron is an essential microelement for plant growth. Tomato is one of the most cultivated fruits and vegetables in the world, and boron deficiency severely inhibits its yield and quality. However, the mechanism of tomato in response to boron deficiency remains largely unclear. Here, we investigated the physiological and molecular bases of the boron deficiency response in hydroponically grown tomato seedlings. Boron deficiency repressed the expression of genes associated with nitrogen metabolism, while it induced the expression of genes related to the pentose phosphate pathway, thereby altering carbon flow to provide energy for plants to cope with stress. Boron deficiency increased the accumulation of copper, manganese and iron, thereby maintaining chlorophyll content and photosynthetic efficiency at the early stage of stress. In addition, boron deficiency downregulated the expression of genes involved in cell wall organization and reduced the contents of pectin and cellulose in roots, ultimately retarding root growth. Furthermore, boron deficiency markedly altered phytohormone levels and signaling pathways in roots. The contents of jasmonic acid, jasmonoy1-L-isoleucine, trans-zeatin riboside, abscisic acid, salicylic acid, and SA glucoside were decreased; in contrast, the contents of isopentenyladenine riboside and ethylene precursor 1-aminocyclopropane-1-carboxylic acid were increased in the roots of boron-deficient tomato plants. These results collectively indicate that tomato roots reprogram carbon/nitrogen metabolism, alter cell wall components and modulate phytohormone pathways to survive boron deficiency. This study provides a theoretical basis for further elucidating the adaptive mechanism of tomato in response to boron deficiency.

Evaluation and driving force analysis of the water-energy‑carbon nexus in agricultural trade for RCEP countries

Water utilization, energy consumption, and carbon emissions are mutually intertwined and play vital roles in agricultural supply chains. Identifying the water-energy‑carbon (WEC) nexus relationships along with its driving forces is of great importance to alleviate resource scarcity and advance a green economy. This study utilizes multiregional input–output (MRIO) analysis and proposes a new indicator, nexus intensity, to investigate the relationship among water, energy, and carbon flows in agricultural trade; furthermore, it modifies the gravity trade model to explore the hidden driving forces for the WEC nexus. The Regional Comprehensive Economic Partnership (RCEP) countries are used as a case study, and the results show that large volumes of WEC flow roughly from the southeast to the northwest. China plays an active role in agricultural trade, contributing 53.34%, 62.00%, and 64.09% of RCEP agriculture-related water utilization, energy consumption, and carbon emissions, respectively. For nexus intensity on the production side, countries with less agriculture-related WEC tend to have extreme situations of extreme resource utilization or emissions. Such situations have become more balanced on the consumption side. Exporters exert a greater impact on agricultural trade than importers. Small population countries such as Australia, New Zealand, and Cambodia serve as granaries for other countries. In addition, countries with higher carbon emissions tend to import carbon-intensive products from other countries. By analyzing the linkages between water, energy, and carbon associated with agricultural products and excavating driving forces, this study provides insights for nexus management on improving resource use efficiency and reducing carbon emissions through transnational trade.

Integration of carbon capture in a pulp mill—effect of strategic development towards better biomass resource utilization

The pulp and paper industry has an important role in the industrial transition towards net zero or negative emissions, given its renewable biomass-based feedstock and energy supply. In particular, pulp and paper mills have large existing sources of biogenic CO2, with a high potential to contribute to carbon dioxide removal through carbon capture and storage (CCS). To effectively navigate anticipated changes in feedstock and energy markets, there is a need for a better understanding of how different technology pathways for the pulp and paper industry interact with one another, for instance, how enhanced valorization of biomass side streams may affect the potential for carbon capture. This paper aims to investigate the effect of combining carbon capture with lignin extraction in a chemical pulp mill. Pinch analysis is used to study how the targets for heat recovery, fuel usage and electricity generation, are affected by different mill and capture configurations. Based on these results, the effect on carbon flows is evaluated. The results show that when carbon capture technology is implemented and fuel use is minimized at the case-study mill, there is still enough heat available from the recovery boilers to supply the process needs without requiring usage of a utility boiler. However, when carbon capture is combined with lignin extraction, the heat production of the recovery boilers is no longer sufficient to cover the process demands, and additional heat from a utility boiler is required. However, this case implies that some of the carbon leaves the mill embedded in the extracted lignin product, which can be expected to have a higher value than captured carbon dioxide. When back-pressure electricity production was maximized for the different mill configurations, a very high fuel-to-electricity efficiency could be achieved, but since the CO2 emissions from the utility boiler were not assumed to be captured, this would lead to more carbon being emitted compared to the capture scenarios with minimized fuel use.

Metabolic flux phenotyping of secondary metabolism in cyanobacteria.

Cyanobacteria generate energy from photosynthesis and produce various secondary metabolites with diverse commercial and pharmaceutical applications. Unique metabolic and regulatory pathways in cyanobacteria present new challenges for researchers to enhance their product yields, titers, and rates. Therefore, further advancements are critically needed to establish cyanobacteria as a preferred bioproduction platform. Metabolic flux analysis (MFA) quantitatively determines the intracellular flows of carbon within complex biochemical networks, which elucidate the control of metabolic pathways by transcriptional, translational, and allosteric regulatory mechanisms. The emerging field of systems metabolic engineering (SME) involves the use of MFA and other omics technologies to guide the rational development of microbial production strains. This review highlights the potential of MFA and SME to optimize the production of cyanobacterial secondary metabolites and discusses the technical challenges that lie ahead.

Dynamic simulation research on urban green transformation under the target of carbon emission reduction: the example of Shanghai

This paper aimed to predict the trend of carbon emissions during the green transformation process in Shanghai, with a focus on the city’s urban system structure. Green development has become an inevitable trend in urban progress, as traditional urban development has led to severe environmental problems caused by the emissions of a large amount of carbon dioxide. This study was motivated by the need for cities to actively pursue green transformation and achieve carbon peaking targets. Through a literature analysis, it was found that urban green transformation is influenced by various factors such as economy, energy, population, technology, and policy. Furthermore, carbon dioxide emissions primarily arise from fossil fuels and are regulated by carbon emission trading (CET) policies. With this knowledge, the urban system was divided, and the flow of carbon was analyzed. Using the general methodology of the IPCC, the carbon production resulting from energy consumption in Shanghai from 2014 to 2019 is calculated to construct an urban system dynamic (SD) model, which is used to predict the carbon emissions expected during the green transformation from 2020 to 2025. The key findings of the study are as follows: (1) The dynamic model of the urban green transformation system proved to be effective in predicting carbon emissions. (2) Based on the current status of green transformation in Shanghai, the city is capable of achieving its expected carbon emission peaking target by 2025. (3) The progress and timing of green transformation and carbon peaking in Shanghai vary across different scenarios, highlighting the importance of collective adjustments to identify the most appropriate path for urban green transformation. These findings provide valuable insights for cities seeking to adopt green development measures, facilitating the acceleration of their green transformation efforts and early attainment of carbon peaking targets.