Microbial responses to CO₂ during carbon sequestration : insights into an unexplored extreme environment

textWhen CO₂ is sequestered into deep saline aquifers, significant changes to the biogeochemistry of the system are inevitable and will affect native microbial populations both directly and indirectly. These communities are important as they catalyze many geochemical reactions in these reservoirs. We present evidence that the injection of CO₂ will cause a large scale disturbance to subsurface microbial populations which will ultimately affect the solution and mineral trapping of CO₂ as well as the movement of CO₂ charged water through the subsurface. Representative subsurface microorganisms including a Gram negative bacterium (G⁻), two Gram positive bacteria (G⁺), and an archaeon were tested for CO₂ survival at pressures up to 50 bar and exposure times up to 24 hours. CO₂ tolerance varied but shows effects on microbes is more complex than just decreasing pH and is not significantly dependent on cell wall structure. Imaging reveals that CO₂ disrupts the cytoplasm possibly from changes to intracellular pH. The geochemical effect of CO₂ stress is a decrease in metabolic activity such as Fe reduction and methanogenesis. Subsurface microbial populations interact with the surrounding reservoir minerals which likely influence their ability to survive under CO₂ stress. When the G⁻ organism was grown in the presence of a mineral substrate, survival depended on the mineral type. Quartz sandstone provided a good substrate for survival while kaolinite provided a poor substrate for survival. Biofilms on quartz sandstone were rich in extracellular polymeric substances (EPS) that likely act as a barrier to slow the penetration of CO₂ into the cell. The release of toxic metals from mineral dissolution at high PCO₂ enhanced cell death. To understand the long term effects of CO₂ on microbial communities, water samples were taken from CO₂ springs in the western United States and compared to unaffected springs. Community 16S rRNA sequence data suggests that CO₂ exposed environments exhibit lower microbial diversity, suggesting environmentally stressed communities. However, differences among diversity in the springs surveyed also indicates other environmental factors that affect diversity beyond CO₂. Furthermore, the isolation of a novel fermentative Lactobacillus strain from a CO₂ spring, indicates viable microbial communities can exist at high PCO₂.Geological Science

TOXICITY STUDY OF CO2 RELEASE IN BIOGAS PROCESS USING COMPUTATIONAL FLUID DYNAMICS MODELING

Biogas processing technologies have been widely applied in industries due to the limitation of non-renewable energy as a source of energy. Together with the biogas production, the emission of carbon dioxide gas from the product also brings the major concern on how safe the carbon dioxide gas concentration from the biogas industry could be. In fact, accidental release of carbon dioxide may cause severe damage and losses during the biogas production. Example of biogas production is landfill gas (LFG) that produces by anaerobic condition through the degradation of municipal solid waste by microorganism. The ability to predict foreseeable accidental scenarios and investigate their consequences is a fundamental aspect in the assessment of the risk of a process or technology. However, due to the limited operational experience in biogas, the process to identify the hazard especially toxicity associated with a larger scale process like biogas become more difficult and complicated. This paper presents an early investigation on how the carbon dioxide gas will react and disperse to the atmosphere due to the leaking in biogas process. Besides, the most important part for this project is to find out the toxicity safe distance on carbon dioxide release in biogas process base on its concentration. Thus, a Computational Fluid Dynamic (CFD) modeling is used to simulate the dispersion behavior of biogas from pressurized release into the atmosphere. CFD is the well-known tool used to investigate the behavior of released substance especially liquid and gas. CFD also equipped with a branch of fluid mechanics that involve algorithm and numerical method to solve the problem related with the fluid flow. In comparison with the natural gas, biogas will shows higher concentration of carbon dioxide because of the low carbon dioxide content in the natural gas. Hence, it proof that biogas is more toxicity than natural gas in term of carbon dioxide release

Piezo-tolerant natural gas-producing microbes under accumulating pCO2

<p>Background: It is known that a part of natural gas is produced by biogenic degradation of organic matter, but the microbial pathways resulting in the formation of pressurized gas fields remain unknown. Autogeneration of biogas pressure of up to 20 bar has been shown to improve the quality of biogas to the level of biogenic natural gas as the fraction of CO2 decreased. Still, the pCO2 is higher compared to atmospheric digestion and this may affect the process in several ways. In this work, we investigated the effect of elevated pCO2 of up to 0.5 MPa on Gibbs free energy, microbial community composition and substrate utilization kinetics in autogenerative high-pressure digestion. Results: In this study, biogas pressure (up to 2.0 MPa) was batch-wise autogenerated for 268 days at 303 K in an 8-L bioreactor, resulting in a population dominated by archaeal Methanosaeta concilii, Methanobacterium formicicum and Mtb. beijingense and bacterial Kosmotoga-like (31% of total bacterial species), Propioniferax-like (25%) and Treponema-like (12%) species. Related microorganisms have also been detected in gas, oil and abandoned coal-bed reservoirs, where elevated pressure prevails. After 107 days autogeneration of biogas pressure up to 0.50 MPa of pCO2, propionate accumulated whilst CH4 formation declined. Alongside the Propioniferax-like organism, a putative propionate producer, increased in relative abundance in the period of propionate accumulation. Complementary experiments showed that specific propionate conversion rates decreased linearly from 30.3 mg g−1 VSadded day−1 by more than 90% to 2.2 mg g−1 VSadded day−1 after elevating pCO2 from 0.10 to 0.50 MPa. Neither thermodynamic limitations, especially due to elevated pH2, nor pH inhibition could sufficiently explain this phenomenon. The reduced propionate conversion could therefore be attributed to reversible CO2-toxicity. Conclusions: The results of this study suggest a generic role of the detected bacterial and archaeal species in biogenic methane formation at elevated pressure. The propionate conversion rate and subsequent methane production rate were inhibited by up to 90% by the accumulating pCO2 up to 0.5 MPa in the pressure reactor, which opens opportunities for steering carboxylate production using reversible CO2-toxicity in mixed-culture microbial electrosynthesis and fermentation.</p

Superoptimal CO2 Reduces Seed Yield in Wheat

Although projected terrestrial CO2 levels will not reach 1000 μmol moI-1 (0.1%) for many decades, CO2 levels in growth chambers and greenhouses routinely exceed that concentration. CO2 levels in life support systems in space can exceed 10,000 μmol moI-1 (1%) CO2. Numerous studies have examined CO2 effects up to 1000 μmol mol-1, but theoretical and some experimental evidence indicates that the beneficial effects of CO2 continue past 1000 μmol mol-1 and are near-optimal for wheat at about 1200 μmol mol-1. We studied the effects of near-optimal and superoptimal CO2 levels (\u3e1200 μmol mol-1) on yield of two cultivars of hydroponically grown wheat in 12 trials. Increasing CO2 from suboptimal to near-optimal (350 to 1200 μmol mol-1) increased vegetative growth by 25% and seed yield by 15% in both cultivars. Yield increases were primarily the result of an increased number of heads m-2. Further elevation of CO2 to 2500 μmol mol-1reduced seed yield by 22% in cv. \u27Veery-10\u27 and by 15% in cv. \u27USU-Apogee\u27. Superoptimal CO2 did not decrease the number of heads m-2, but reduced seeds per head by 10% and mass per seed by 11%. CO2 toxicity occurred over a wide range of light levels. Subsequent trials revealed that superoptimal CO2 in the 2 weeks before and after anthesis mimicked the effect of constant superoptimal CO2. Furthermore, near-optimal CO2 in the 2 weeks before and after anthesis mimicked the effect of constant near-optimal CO2. Nutrient concentration of leaves and heads was not affected by CO2. The yield decreases may be a response mediated by ethylene

Cymantrene–Triazole "Click" Products: Structural Characterization and Electrochemical Properties

We report the first known examples of triazole-derivatized cymantrene complexes (η5-[4-substituted triazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I), obtained via a “click” chemical synthesis, bearing a phenyl, 3-aminophenyl, or 4-aminophenyl moiety at the 4-position of the triazole ring. Structural characterization data using multinuclear NMR, UV–vis, ATR-IR, and mass spectrometric methods are provided, as well as crystallographic data for (η5-[4-phenyltriazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I) and (η5-[4-(3-aminophenyl)triazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I). Cyclic voltammetric characterization of the redox behavior of each of the three cymantrene–triazole complexes is presented together with digital simulations, in situ infrared spectroelectrochemistry, and DFT calculations to extract the associated kinetic and thermodynamic parameters. The trypanocidal activity of each cymantrene–triazole complex is also examined, and these complexes are found to be more active than cymantrene alone

Consequence Study on Toxicity of Carbon Dioxide Release in Seawater

Consequence study of carbon dioxide release in seawater is becoming the one of the prevailing environmental concerns in this recent decade, mainly due to its potential harm to the ecosystem as well as the livelihood of the people whom depends upon it. Normally, carbon dioxide release is likely to take place in naturally occurring seabed fracture or man-made structure such as underwater carbon sequestering region or pipeline rupture. According to past simulation done by preceding experts, the majority of the results describes that the carbon dioxide plume tend not to escape to the surface of the seawater and is usually localized or confined in within certain boundary if the tidal mixing effect is minimal. Most of the modeling of carbon dioxide behavior done is based on the respective mathematical correlation or formulation designed to increase accuracy and reliability. However, for the sake of simplicity and compatibility with the scope of this project, the behavior of carbon dioxide toxicity release in seawater will be modeled using ANSYS Fluent Simulation Software using pertinent data acquired from other peer-reviewed research paper done by Fadzil (2012) and Dissanayake (2012). The location of the scenario chosen for this simulation is within the vicinity of South China Sea, as it is currently the target area for carbon capture storage system by the Malaysian authority. From the simulation of sub-seabed leakage, it is found that the simulation result is in great conformance with the physiochemical modeling of carbon dioxide release in seawater conducted by Dewar et al (2013). The maximum concentration of carbon dioxide and dispersed plume height rise acquired are 8.50E+09 ppm and 75.12 m respectively, yielding percentage errors of less than 10% for both of the parameters. However, pipeline leakage scenario is not taken into account to the due lack of experimental and simulation data for model verification and validation. The result obtained from this simulation is hoped to be utilized by any party involved in Carbon Sequestration and Storage System Project in Malaysia as value-added data

C02 Emissions and Economic Growth: A Panel Data Analysis Evidence from Developing African Countries

This paper tests the Environmental Kuznet Hypothesis using data from 23 African countries for the period 1980–2019&nbsp;&nbsp; in the Pedroni approach to panel cointegration analysis. The evidence suggests that both real GDP and energy consumption have a substantial effect on CO2 emission in most countries studied though energy consumption has less effect. However, in most countries, as income increases, the level of emission declines consistently with the EKC hypothesis. However, the econometric result, their interpretation, and their likely policy implications have to be taken with caution since there is a high degree of heterogeneity among the countries in terms of energy consumption,&nbsp; real income as well as&nbsp; CO2 emissions. This is more so when the analysis of the trend in the growth of the three variables used in estimation and the estimated results of fully modified OLS show large divergence among countries. However, the study recommends that, since a great number of economies in the study buttressed the EKC, therefore, the current policy on growth and energy consumption may be pursued without necessarily affecting the quality of their environment. However, other countries should implement strong regulatory and market-based policies on highly energy-intensive sectors to reduce their current level of emissions and attain sustainable, environment-friendly growth

C02 Emissions and Economic Growth: A Panel Data Analysis Evidence from Developing African Countries

This paper tests the Environmental Kuznet Hypothesis using data from 23 African countries for the period 1980–2019&nbsp;&nbsp; in the Pedroni approach to panel cointegration analysis. The evidence suggests that both real GDP and energy consumption have a substantial effect on CO2 emission in most countries studied though energy consumption has less effect. However, in most countries, as income increases, the level of emission declines consistently with the EKC hypothesis. However, the econometric result, their interpretation, and their likely policy implications have to be taken with caution since there is a high degree of heterogeneity among the countries in terms of energy consumption,&nbsp; real income as well as&nbsp; CO2 emissions. This is more so when the analysis of the trend in the growth of the three variables used in estimation and the estimated results of fully modified OLS show large divergence among countries. However, the study recommends that, since a great number of economies in the study buttressed the EKC, therefore, the current policy on growth and energy consumption may be pursued without necessarily affecting the quality of their environment. However, other countries should implement strong regulatory and market-based policies on highly energy-intensive sectors to reduce their current level of emissions and attain sustainable, environment-friendly growth

Indoor AIr Quality

An indoor air quality study was conducted on a ‘net-zero energy’ school using a TSI Velocicalc Model 9555-p with probe model 982, passive radon monitors, visual inspection protocol, and an indoor environmental quality survey of school faculty and staff. Average indoor temperature, relative humidity, and carbon dioxide levels in several areas within the school were not within IAQ guidelines. Three rooms on the school’s grounds had radon levels exceeding the action level. Recommended solutions included installing return and supply air ducts in hallways and relative humidity and temperature monitors in classrooms with high-pitched ceilings