Atmospheric Carbon Dioxide Levels Research Articles

A comprehensive review of efficient capacity estimation for large-scale CO2 geological storage

Geological carbon storage and sequestration (GCS), a key method within carbon capture and sequestration (CCS), is globally recognized as an effective strategy to reduce atmospheric carbon dioxide (CO2) levels and combat the greenhouse effect. However, discrepancies between projected and actual storage capacities, especially in large-scale CO2 storage, have raised concerns among stakeholders regarding potential overestimations. This paper reviews the definitions and methods used to estimate storage capacity, highlighting variations and providing a practical guide for predictions while suggesting directions for future research. We discuss numerous analytical and numerical models that account for dynamic constraints such as safety considerations, trapping mechanisms, and reservoir performance, primarily focusing on local scales. These models enhance the accuracy of capacity estimations over conventional static models by quantifying CO2 storage capacity both spatially and temporally. Additionally, this review underscores the need for sophisticated evaluations of large-scale storage. We introduce two pivotal tools designed for basin-scale capacity estimation and discuss the challenges associated with expanding dynamic capacity assessments to larger scales. In conclusion, the paper explores the burgeoning use of machine learning-based models, advocating for future research efforts to leverage machine learning in developing integrated tools that offer more comprehensive and precise capacity estimations for GCS.

A network-based modeling framework reveals the core signal transduction network underlying high carbon dioxide-induced stomatal closure in guard cells.

Stomata are pores on plant aerial surfaces, each bordered by a pair of guard cells. They control gas exchange vital for plant survival. Understanding how guard cells respond to environmental signals such as atmospheric carbon dioxide (CO2) levels is not only insightful to fundamental biology but also relevant to real-world issues of crop productivity under global climate change. In the past decade, multiple important signaling elements for stomatal closure induced by elevated CO2 have been identified. Yet, there is no comprehensive understanding of high CO2-induced stomatal closure. In this work, we assemble a cellular signaling network underlying high CO2-induced stomatal closure by integrating evidence from a comprehensive literature analysis. We further construct a Boolean dynamic model of the network, which allows in silico simulation of the stomatal closure response to high CO2 in wild-type Arabidopsis thaliana plants and in cases of pharmacological or genetic manipulation of network nodes. Our model has a 91% accuracy in capturing known experimental observations. We perform network-based logical analysis and reveal a feedback core of the network, which dictates cellular decisions in closure response to high CO2. Based on these analyses, we predict and experimentally confirm that applying nitric oxide (NO) induces stomatal closure in ambient CO2 and causes hypersensitivity to elevated CO2. Moreover, we predict a negative regulatory relationship between NO and the protein phosphatase ABI2 and find experimentally that NO inhibits ABI2 phosphatase activity. The experimental validation of these model predictions demonstrates the effectiveness of network-based modeling and highlights the decision-making role of the feedback core of the network in signal transduction. We further explore the model's potential in predicting targets of signaling elements not yet connected to the CO2 network. Our combination of network science, in silico model simulation, and experimental assays demonstrates an effective interdisciplinary approach to understanding system-level biology.

Microalgal biorefinery as a sustainable and cost-effective platform for co-production of high-value-added products/metabolites: An insight into emerging trends, challenges, and opportunities

In biorefining, biomass is processed sustainably to produce multiple high-value products. The biorefinery concept has been acknowledged as the most promising tactic for creating a biomass-based business/industry. Biomass from microalgae includes a variety of beneficial bioactive elements like pigments, proteins, polyunsaturated fatty acids, and polyhydroxyalkanoates (PHAs). In addition, microalgal cells can also be utilized as a source of raw materials to make biofuel. In order to reduce overall process costs, these value-added chemicals can be extracted concurrently or sequentially with biodiesel. Further, to promote microalgae in the industrial sector, a biorefinery approach is crucial. Researchers have been eager to use the bio-refinery strategy for obtaining the high-value constituents entrapped by microalgae. Microalgae not only contain a variety of valuable chemicals but also contribute in lowering the atmospheric levels of anthropogenic carbon dioxide. These advantages make microalgae a viable resource for bio-refinery strategy. This review intends to emphasize the valuable properties of microalgae together with their significance to people. This article also highlights the recent as well as upcoming developments that will increase the viability of bio-processing for microalgal-based bio-refinery.

Improvement of Thick Coal Seam Gas Drainage Efficiency Using Highly Pressurized Multidischarge CO2 Gas Fracturing Technique.

Thick coal seam fracture stimulations were conducted to enhance pre-gas drainage efficiency through the use of a highly pressurized multidischarge carbon dioxide gas fracturing technique. This method also offers potential as a strategy for carbon dioxide sequestration, aiding in the reduction of atmospheric carbon dioxide levels and thereby contributing to the fight against climate change. This paper discusses findings from both field experiments and numerical simulations. Data from the field show that the multidischarge fracturing approach significantly improves permeability in thick coal seams, thereby boosting gas drainage effectiveness. Additionally, the impact of increasing the number of fracturing devices is more pronounced at distances of 2.5 or 7.5 m from the borehole but becomes more complex at 12.5 m or further. The numerical simulations reveal that this technique primarily enhances coal seam gas drainage by improving the seam permeability and establishing a gas pressure gradient within the seam. It is noted that the radius of failure around the borehole wall expands with higher discharge pressures, while the radius of effective drainage narrows as the gap between discharge heads increases. Moreover, adding more discharge sets significantly influences the deformation and permeability of the coal seam within a 5 m radius of the fracturing borehole, but the influence is not obvious after 10 m from the fracturing borehole.

Deglacial export of pre-aged terrigenous carbon to the Bay of Biscay

Abstract. The last deglaciation is the most recent relatively well-documented period of pronounced and fast climate warming, and, as such, it holds important information for our understanding of the climate system. Notably, while research into terrestrial organic carbon reservoirs has been instrumental in exploring the possible sources of atmospheric carbon dioxide during periods of rapid change, the underlying mechanisms are not fully understood. Here we investigate the mobilization of organic matter to the Bay of Biscay, located in the north-eastern Atlantic Ocean off the coasts of France and Spain. Specifically, we focus on the area that was the mouth of the Channel River during the last deglaciation, where an enhanced terrigenous input has been reported for the last glacial–interglacial transition. We conducted a comprehensive suite of biomarker analyses (e.g. n-alkanes, hopanes and n-alkanoic acids) and isotopic investigations (radiocarbon dating and δ13C measurements) on a high-resolution sedimentary archive. The present study provides the first direct evidence for the fluvial supply of immature and ancient terrestrial organic matter to the core location. Moreover, our results reveal the possibility of permafrost carbon export to the ocean, driven by processes such as deglacial warming and glacial erosion. These findings are consistent with observations from other regions characterized by present or past permafrost conditions on land, which have shown that permafrost thaw and glacial erosion can lead to carbon remobilization, potentially influencing atmospheric carbon dioxide levels.

Dynamic modelling and simulation of the Graz Cycle for a renewable energy system

Critical atmospheric carbon dioxide levels and, in response, an increasing shift toward variable renewable energy sources causes the need of transient operation for thermal power plants coupled with carbon capture and storage. In this regard, dynamic process simulations are a valuable tool for predicting the cycling performance of power plants. In this study, the proposed Graz Cycle, an oxy-combustion power plant fired with natural gas, is investigated and modelled in (a) the steady-state design-point (i.e., full-load), (b) steady-state off-design (i.e., part-load), and (c) dynamic conditions. At full loads, the Graz Cycle power plant achieves a maximum net plant efficiency of 54.5%, comparable to the performance results of the competing Allam cycle found in relevant studies. In the off-design simulation, considering for the first time compressor component maps with variable inlet guide vanes, the load is reduced down to 50% achieving improved performance results compared to previous studies. The dynamic simulation boils down to a ramp rate analysis and shows that practical ramp rates of 5.55 %/min for load decrease and 18.18 %/min for load increase can be reached. The results show that the high ramp rates of the Graz Cycle enable balancing services to the electrical grid next to clean and dispatchable power generation. In this study, a systematic first-principle modelling approach has been developed with the final aim to evolve dynamic models for oxy-combustion carbon capture cycles, and a first-of-its-kind analysis of the dynamic operation of the Graz Cycle is presented.

Comprehensive analysis of Trichoderma ressei mediated CO2 stress attenuating responses and de novo transcriptome sequencing of rice flag leaf

AbstractThe objective of this study was to investigate the alterations in physiological, biochemical, and transcriptional reactions in the flag leaf of rice following the application of Trichoderma as a biofertilizer (BF) at both ambient (aCO2; 395 ppm) and enhanced (eCO2; 550 ppm) carbon dioxide levels. A comparatively smaller percentage change was observed in the photosynthetic parameters, including photosynthetic rate, respiration, and stomatal conductance, subsequent to the introduction of BF in the elevated carbon dioxide (eCO2) environment. Furthermore, biochemical analysis revealed a noteworthy elevation in photosynthetic pigments, total sugar, proline, and ascorbate peroxidase concentration levels in plants treated with BF under ambient and increased carbon dioxide conditions. The buildup of indole‐3‐acetic acid (IAA) was shown to be increased in rice treated with BF under both conditions. Moreover, ICP‐MS analysis demonstrated an augmentation in the levels of vital micronutrients in the experimental group while observing no alterations in the carbon‐to‐nitrogen ratio within the flag leaf. The examination of transcriptional responses in the flag leaf demonstrated an increase in the expression of genes associated with the photosynthetic system, amino acid metabolism, several transporters, including aquaporin, and the phosphate pathway, as well as carbon and nitrogen metabolism. Hence, our work elucidates the effective role of Trichoderma in mitigating the adverse consequences associated with elevated levels of atmospheric carbon dioxide (eCO2).

Mathematical modeling of vehicle carbon dioxide emissions

The demand for transportation, driven by an increasing global population, is continuously rising. This has led to a higher number of vehicles on the road and an increased reliance on fossil fuels. Consequently, the rise in atmospheric carbon dioxide (CO2) levels has contributed to global warming. Therefore, it is important to consider sustainable transportation practices to meet climate change mitigation targets. In this research paper, a non-linear mathematical model is developed to study the dynamics of atmospheric CO2 concentration in relation to human population, economic activities, forest biomass, and vehicle population. The developed model is analyzed qualitatively to understand the long-term behavior of the system's dynamics. Model parameters are fitted to actual data of world population, human economic activities, atmospheric CO2, forest biomass, and vehicle population. It is shown that increased vehicular CO2 emissions have a potential contribution to the increase in atmospheric CO2 and the decline of human population. Numerical simulations are carried out to verify the analytical findings and we performed global sensitivity analysis to explore the impacts of different sensitive parameters on the CO2 dynamics.

India's biogeochemical capacity to attain food security and remediate climate.

In order to supply wholesome food and slow down climate change, this paper covers India's agrogeological resources. The soils are the result of the weathering of rocks with ages ranging from more than a billion years to the most recent Holocene. Because they are severely deficient in vital minerals, many soils have low agricultural production. In addition to helping to fertilise soils, reduce atmospheric carbon dioxide levels, and stop the acidification of the Indian Ocean, rock powder weathering and biochar have significant positive effects on the productivity of Indian soils. The nutrient density of food is also increased which improves health and lowers the demand for and cost of medical treatment. Remineralization may help to solve Indian soil issues including soil infertility and texture. To improve soil and plant nutrition, dusts of carbonate, basic, and ultrabasic rocks are readily available at mining sites in India combined with biochar. Adding different grain sizes to the soil helps improve the texture of the soil.Silicate and carbonate rock powders enhance soil structure by promoting the creation of soil organic matter and fostering the growth of advantageous microbial communities. These processes offer a low-cost method of remineralizing soils with important macro- and micronutrients. For each significant soil/crop/climate system, an optimised application of India's rock powder resources must be determined through a national research and development programme. India's capacity to adapt to the mounting challenges of population expansion and climate change would be significantly improved by the findings of this study programme.

A Case Study on the CO2 Sequestration in Shenhua Block Reservoir: The Impacts of Injection Rates and Modes

Carbon capture and storage (CCS) is the most promising method of curbing atmospheric carbon dioxide levels from 2020 to 2050. Accurate predictions of geology and sealing capabilities play a key role in the safe execution of CCS projects. However, popular forecasting methods often oversimplify the process and fail to guide actual CCS projects in the right direction. This study takes a specific block in Shenhua, China as an example. The relative permeability of CO2 and brine is measured experimentally, and a multi-field coupling CO2 storage prediction model is constructed, focusing on analyzing the sealing ability of the block from the perspective of injection modes. The results show that when injected at a constant speed, the average formation pressure and wellbore pressure are positively correlated with the CO2 injection rate and time; when the injection rate is 0.5 kg/s for 50 years, the average formation pressure increases by 38% and the wellbore pressure increases by 68%. For different injection modes, the average formation pressures of various injection methods are similar during injection. Among them, the pressure increases around the well in the decreasing injection mode is the smallest. The CO2 concentration around the wellbore is the largest, and the CO2 diffusion range continues to expand with injection time. In summary, formation pressure increases with the increase in injection rate and injection time, and the decreasing injection mode has the least impact on the increase in formation pressure. The CO2 concentration is the largest around the well, and the CO2 concentration gradually decreases. The conclusion helps determine the geological carrying capacity of injection volumes and provides insights into the selection of more appropriate injection modes. Accurate predictions of CO2 storage capacity are critical to ensuring project safety and monitoring potentially hazardous sites based on reservoir characteristics.

Electrochemical Direct Air Capture of Carbon Dioxide by a Redox-Mediated Salt Splitting Process

Direct air capture of carbon dioxide is an important emerging direction for electrochemical separation technology. Carbon dioxide removal has a critical role to play in the coming century as a complement to deep decarbonization efforts, because removal may offset emissions we cannot avoid, such as agriculture for food security. Direct air capture might even be used to decrease the atmospheric carbon dioxide level if the value at which it stabilizes is deemed too high. Electrochemical methods allow us to power a carbon removal device directly by carbon-free electricity. Here, we present a salt splitting process, based on bipolar membrane electrodialysis, which begins with a neutral electrolyte (e.g. KCl), and creates a strong base (e.g., KOH) and a strong acid (e.g., HCl). The base may then be used to absorb carbon dioxide from ambient air; the acid is then used to extract the carbon dioxide by recombining with the base, reversing the salt splitting process. The process is driven by iron(II/III) hexacyanide redox on carbon cloth electrodes, which is kinetically facile and contributes relatively little to the cell voltage.Energy required for redox-mediated salt splitting depends on contributions from water dissociation in the bipolar membrane, ohmic resistances in ion exchange membranes and electrolyte layers, and electrode reactions. We show that the largest contribution to the energy required comes from the bipolar membrane, motivating further research on bipolar membrane development. We also discuss the role of ion exchange membranes in this system: these membranes must provide high ion conductivity while providing selectivity against leakage of acid and base products. Several commercial membranes were screened for conductivity and water content, and their electrodialysis performance is compared. Finally, we use technoeconomic modeling to assess how electrodialysis operating conditions and electrolyte composition affect energy, land, and water demands of a continuously operating direct air capture process, with redox-mediated salt splitting as the centerpiece. Figure 1

The impact of global warming on polar marine life

The global region is currently facing enormous environmental issues of global warming, which is affecting the entire Earth's ecosystem, especially the natural environment of the oceans. Global warming is a natural phenomenon caused by energy imbalances caused by the cumulative greenhouse effect absorbed and released by the terrestrial air system. The ongoing energy buildup in the terrestrial air system has led to rising temperatures and global warming. Natural disasters and biological chain fracturing are just two examples of the dangers that climate change poses to various facets of humanity. The primary cause of this phenomena is one of the key causes of global farming. In addition, it poses a major threat to the equilibrium of natural ecosystems because of the astounding amount of carbon dioxide emissions produced annually, which directly contributes to an increase in atmospheric carbon dioxide levels. Climate change on the surface of the Earth is a direct outcome of this "greenhouse effect." Environmental pollution, which is getting worse every day, has grown to be a significant global issue and is one of the main causes of global warming. Today, studies on global climate change have amply demonstrated that the Earth's surface temperature has been increasing since the end of the last century. At the same time, this phenomenon has had a significant impact and harm on human survival.

Research on the Impact of Energy on Emission Reduction and Environmental Protection

All nations are concerned about how to deal with the problem of the increasing carbon dioxide emissions in the globe today. By replacing traditional non-renewable energy with clean energy, greenhouse gas emissions can be reduced, thus helping to tackle climate change. Since the industrial revolution, global greenhouse gas emissions and the amount of energy generated from fossil fuels have increased dramatically, resulting in the highest levels of atmospheric carbon dioxide in 400,000 years. Therefore, this article aims to analyze the data on various energy consumption and carbon dioxide emissions by incorporating them into a multiple linear model, in order to identify the impact of different energy sources on carbon dioxide emissions. The results show that only oil, coal, and hydropower have a significant positive correlation with carbon dioxide emissions, while other energy sources do not have a significant relationship. Based on the above analysis, it is hoped to provide some meaningful recommendations.

The ocean carbon pool: a vital component of the global carbon cycle

The global carbon cycle is an integral part of the Earth System. Of the land, atmosphere, and ocean components of the global carbon cycle that exchange carbon on the timescales of decades to centuries, the ocean contains more than 90% of carbon. The ocean carbon pool represents a critical component of the Earth's carbon cycle, playing a pivotal role in regulating atmospheric carbon dioxide (CO2) levels and influencing climate dynamics. The exponential increase of total anthropogenic CO2 emissions in the industrial era implies the ocean's uptake has increased exponentially, reaching 2.5 ± 0.6 Pg C yr-1 for 2009-2018. Without the ocean and land sinks, atmospheric CO2 levels would be close to 600 ppm. The ocean carbon pool comprises dissolved inorganic carbon (DIC), organic carbon, and particulate organic matter, collectively responsible for the sequestration and release of carbon into the atmosphere. Phytoplankton, the microscopic marine plants, play a fundamental role in the oceanic carbon cycle by photosynthesizing and fixing atmospheric CO2 into organic matter. This organic matter can be transferred to the deep ocean through the biological pump, further contributing to the storage of carbon in the form of sinking particles. The bulk of the global ocean margin represents a carbon sink of ~0.1-0.2 Pg C. Oceanic processes, such as ocean circulation and upwelling, help redistribute carbon from surface waters to the deep ocean. The solubility pump, which is driven by changes in temperature and salinity, also affects the solubility of CO2 in seawater. These natural processes work to mitigate the increase in atmospheric CO2 concentrations and help regulate global temperatures.

Carbon Sequestration Potential of Trees in Urban Vegetation Islands: A Case Study

Aim: Increasing levels of atmospheric carbon dioxide (CO2) and other “greenhouse” gases contribute to an increase in atmospheric temperature. Trees act as a sink for CO2 by fixing carbon during photosynthesis and storing excess carbon as biomass. The current study focuses on the contribution of vegetation within Janki Devi Bajaj Government Girls College, Kota towards carbon sequestration potential and climate regulation.
 Study Design: Non-destructive method of biomass estimation was used to measure the GBH of individual trees on the campus.
 Place and Duration: The study was conducted in Janki Devi Bajaj Government Girls College, Kota in Rajasthan, India from July 2022 to June 2023.
 Methodology: Above-ground biomass (AGB) and below-ground biomass (BGB) were calculated with the help of field measures of diameter at breast height (DBH) of the trees using allometric equations and Carbon equivalent was calculated with scientifically verified formula.
 Results: The present study enumerated a total of 849 trees belonging to 43 tree species on the campus. The most dominant species was Syzygium cumini (L.) Skeels with a total of 163 trees followed by Phoenix sylvestris (L.) Roxb (121 trees) and Eucalyptus obliqua L'Her (97 trees). The above-ground biomass (AGB) and below-ground biomass (BGB) of all the trees on the campus are equivalent to 373937 kg and 56090.54 kg, respectively. The total biomass accumulated is 430027.5 kg and the total carbon content of the campus trees is equal to 215013.75 kg. The total carbon sequestered by all the trees in a year is 788.38 tons. In other words, on average carbon sequestered by an individual tree on the campus is 928.60 kg/year or 0.93 tons/year.
 Conclusion: Urban green islands are likely to have a wider impact on biomass accumulation in turn carbon storage and sequestration in comparison to other structural parameters like species richness or density. Thus, in urban areas, the amount of potential carbon storage is positively influenced by increasing biomass.

OutcropHyBNet: Hybrid Backbone Networks with Data Augmentation for Accurate Stratum Semantic Segmentation of Monocular Outcrop Images in Carbon Capture and Storage Applications.

The rapid advancement of climate change and global warming have widespread impacts on society, including ecosystems, water security, food production, health, and infrastructure. To achieve significant global emission reductions, approximately 74% is expected to come from cutting carbon dioxide (CO2) emissions in energy supply and demand. Carbon Capture and Storage (CCS) has attained global recognition as a preeminent approach for the mitigation of atmospheric carbon dioxide levels, primarily by means of capturing and storing CO2 emissions originating from fossil fuel systems. Currently, geological models for storage location determination in CCS rely on limited sampling data from borehole surveys, which poses accuracy challenges. To tackle this challenge, our research project focuses on analyzing exposed rock formations, known as outcrops, with the goal of identifying the most effective backbone networks for classifying various strata types in outcrop images. We leverage deep learning-based outcrop semantic segmentation techniques using hybrid backbone networks, named OutcropHyBNet, to achieve accurate and efficient lithological classification, while considering texture features and without compromising computational efficiency. We conducted accuracy comparisons using publicly available benchmark datasets, as well as an original dataset expanded through random sampling of 13 outcrop images obtained using a stationary camera, installed on the ground. Additionally, we evaluated the efficacy of data augmentation through image synthesis using Only Adversarial Supervision for Semantic Image Synthesis (OASIS). Evaluation experiments on two public benchmark datasets revealed insights into the classification characteristics of different classes. The results demonstrate the superiority of Convolutional Neural Networks (CNNs), specifically DeepLabv3, and Vision Transformers (ViTs), particularly SegFormer, under specific conditions. These findings contribute to advancing accurate lithological classification in geological studies using deep learning methodologies. In the evaluation experiments conducted on ground-level images obtained using a stationary camera and aerial images captured using a drone, we successfully demonstrated the superior performance of SegFormer across all categories.

LIDAR-Based Forest Biomass Remote Sensing: A Review of Metrics, Methods, and Assessment Criteria for the Selection of Allometric Equations

The increasing level of atmospheric carbon dioxide and its effects on our climate system has become a global environment issue. The forest ecosystem is essential for the stability of carbon in the atmosphere as it operates as a carbon sink and provides a habitat for numerous species. Therefore, our understanding of the structural elements of the forest ecosystem is vital for the estimation of forest biomass or terrestrial carbon stocks. Over the last two decades, light detection and ranging (LIDAR) technology has significantly revolutionized our understanding of forest structures and enhanced our ability to monitor forest biomass. This paper presents a review of metrics for forest biomass estimation, outlines metrics selection methods for biomass modeling, and addresses various assessment criteria for the selection of allometric equations for the aboveground forest biomass estimations, using LIDAR data. After examining one hundred publications written by different authors between 1999 and 2023, it was observed that LIDAR technology has become a dominant data collection tool for aboveground biomass estimation with most studies focusing on the use of airborne LIDAR data for the plot-level analysis on a local scale. Parametric-based models dominated in most studies with coefficient of determination (R2) and root mean square error (RMSE) as assessment criteria. In addition, mean top canopy height (MCH) and quadratic mean height (QMH) were reported as strong predictors for aboveground biomass (AGB) estimation. Pixel-based uncertainty analysis was found to be a reliable method for assessing spatial variations in uncertainties.

Calcium isotopic fractionation during aragonite and high-Mg calcite precipitation at methane seeps

The formation of authigenic carbonate in marine environments represents a process that buffers ocean chemistry and atmospheric carbon dioxide levels. The isotopic composition of calcium (δ44/40Ca) in authigenic carbonate can be used to investigate the calcium (Ca) cycle, seawater chemistry, and diagenesis of carbonate rocks, archiving key information on the evolution of the Earth's surface environments. Laboratory experiments have shown that Ca isotopic fractionation during carbonate precipitation – the basis of the δ44/40Ca proxy – is mainly determined by both mineral phase and precipitation rate. However, the precipitation rate of submarine authigenic carbonate is much lower than rates in laboratory experiments. This study investigated the Ca isotopic composition of pore water and carbonate nodules collected from two gravity piston cores and one push core from the Haima seeps in the northern South China Sea. Methane fluxes calculated for the three cores range from 12 to 134 µmol cm−2 yr−1. The core with intermediate methane flux showed evidence of aragonite precipitation, while high-Mg calcite was the dominant mineral phase in the other two cores as indicated by Mg/Ca and Sr/Ca ratios of pore water. Numerical modeling of pore water geochemistry revealed that: (1) precipitation rates of carbonate per unit reactive surface area range from 0.05 to 21 µmol m−2 h−1, which is one to three orders of magnitude lower than rates in precipitation experiments; (2) Ca isotopic fractionation for aragonite precipitation is –1.8 ± 0.3 ‰, close to the reported equilibrium isotopic fractionation in precipitation experiments; and (3) Ca isotopic fractionation for high-Mg calcite precipitation is similar for the two cores (−0.9 ± 0.3 ‰ and −0.8 ± 0.3 ‰), although the modeled precipitation rates differed by two orders of magnitude. These results indicate that mineralogy rather than precipitation rate is the primary control on Ca isotopic fractionation during carbonate precipitation at seeps, resulting in lower δ44/40Ca values of aragonite (0.91±0.06 ‰, N = 4) than of high-Mg calcite (1.41±0.04 ‰, N = 9) reported relative to NIST SRM915a. This study documents distinguishable Ca isotopic fractionation during the formation of methane-derived high-Mg calcite and aragonite, providing fundamental parameters for further exploration of the calcium isotopic composition of marine authigenic carbonates in the geological record.

A review of climate change mitigation and agriculture sustainability through soil carbon sequestration

As a result of human activities such as burning fossil fuels, organic materials, and engaging in unsustainable land practices, atmospheric carbon dioxide (CO2) levels have been steadily rising, heightening worldwide concerns about climate change. It is expected concentrations to grow and changes in CO2 sequestration in agricultural soils as a result of the industrial revolution's acceleration of CO2 emissions. These emissions have been intensified by changes in land use, such as cutting down trees, burning biomass, altering farming operations, draining natural wetlands, and using the wrong methods for managing soil. The present study utilized the systematic literature review method to investigate soil carbon sequestration options as a possible means of reducing the impact of climate change and improving agriculture sustainability. As a result of soil degradation and poor management, soil organic carbon (SOC) levels have decreased, which in turn has increased atmospheric CO2 levels. But cutting-edge land application and modern agricultural management methods have the ability to reduce CO2 emissions. Several methods exist for replenishing depleted SOC, such as repurposing marginal lands for restoration purposes, advocating for reduced or zero-tillage methods in conjunction with cover as well as residue crops, and introducing nutrient cycling through composting, manure usage, and other environmentally friendly approaches to managing soil and water. One holistic approach to fighting climate change is long-term soil carbon sequestration. Soil carbon sequestration offers a comprehensive and efficient strategy for reducing the impact of climate change by recharging depleted soils, increasing biomass production, cleaning surface and underground water sources, and compensating for CO2 emissions through fossil fuels. Soil carbon sequestration presents an exciting opportunity for management of the problems caused by contemporary changes in the environment, and the adoption of these novel approaches is essential for meeting these issues.

Chitosan nanoparticles upregulate C and N metabolism in soybean plants grown under elevated levels of atmospheric carbon dioxide

Despite the wide utilization of chitosan nanoparticles (CSNPs) as a promising approach for sustainable agriculture, their efficiency under elevated CO2 (eCO2), has not been evaluated. The interactive effects of CSNPs and eCO2 were evaluated on the growth and C and N metabolism of soybean plants. Plants were treated with CSNPs and grown under ambient CO2 (410 ppm, aCO2) or eCO2 (645 ppm). Regardless of CO2 level, CSNPs improved the net photosynthetic rate. CSNPs aggravated the effect of eCO2 treatment on the levels of non-structural carbohydrates (i.e., glucose, fructose, sucrose, and starch), especially in shoots, which was inconsistence with the upregulation of carbohydrates metabolizing enzymes. Being the most pivotal energetic and signaling organic compounds in higher plants, the synergistic action of CSNPs and eCO2 on the accumulation of soluble sugars upregulated the N metabolism as indicated by induced activities of nitrate reductase, arginase, glutamate dehydrogenase, glutamine synthetase, and glutamine oxoglutarate aminotransferase which was manifested finally as increased shoot and root total nitrogen content as well as proline and aspartate in roots. At the hormonal level, the coexistence of eCO2 with CSNPs further supports their positive impact on the contents of IAA and, to a lesser extent, GAs. The present data prove that the biofertilization capacity of CSNPs is even more potent under futuristic eCO2 levels and could even further improve the growth and resilience of plants.