• Atmosphere
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• v.28 no.2
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• pp.113-121
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• 2018

In order to monitor greenhouse gases including $CO_2$, various types of surface-, aircraft-, and satellite-based measurement projects have been conducted. These data help understand the variations of greenhouse gases and are used in atmospheric inverse modeling systems to simulate surface fluxes for greenhouse gases. CarbonTracker is a system for estimating surface $CO_2$ flux, using an atmospheric inverse modeling method, based on only surface observation data. Because of the insufficient surface observation data available for accurate estimation of the surface $CO_2$ flux, additional observations would be required. In this study, a system that assimilates aircraft $CO_2$ measurement data in CarbonTracker (CT2013B) is developed, and the estimated results from this data assimilation system are evaluated. The aircraft $CO_2$ measurement data used are obtained from the Comprehensive Observation Network for Trace gases by the Airliner (CONTRAIL) project. The developed system includes the preprocessor of the raw observation data, the observation operator, and the ensemble Kalman filter (EnKF) data assimilation process. After preprocessing the raw data, the modeled value corresponding spatially and temporally to each observation is calculated using the observation operator. These modeled values and observations are then averaged in space and time, and used in the EnKF data assimilation process. The modeled values are much closer to the observations and show smaller biases and root-mean-square errors, after the assimilation of the aircraft $CO_2$ measurement data. This system could also be used to assimilate other aircraft $CO_2$ measurement data in CarbonTracker.

• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.547-555
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• 2020

Microalgae are a promising resource in energy and food production as they are cost-effective for biomass production and accumulate valuable biological resources. In this study, CO2 assimilation, biomass, and lipid production of 4 microalgal species (Chlorella vulgaris, Mychonastes homosphaera, Coelastrella sp., and Coelastrella vacuolata) were characterized at different CO2 concentrations ranging from 1% to 9%. Microscopic observation indicated that C. vulgaris was the smallest, followed by M. homosphaera, C. vacuolata, and Coelastrella sp. in order of size. C. vulgaris grew and consumed CO2 more rapidly than any other species. C. vulgaris exhibited a linear increase in CO2 assimilation (up to 9.62 mmol·day-1·l-1) as initial biomass increased, while the others did not (up to about 3 mmol·day-1·l-1). C. vulgaris, Coelastrella sp., and C. vacuolata showed a linear increase in the specific CO2 assimilation rate with CO2 concentration, whereas M. homosphaera did not. Moreover, C. vulgaris had a greater CO2 assimilation rate compared to those of the other species (14.6 vs. ≤ 11.9 mmol·day-1·l-1). Nile-red lipid analysis showed that lipid production per volume increased linearly with CO2 concentration in all species. However, C. vulgaris increased lipid production to 18 mg·l-1, compared to the 12 mg·l-1 produced by the other species. Thus, C. vulgaris exhibited higher biomass and lipid production rates with greater CO2 assimilation capacity than any other species.

• Korean Journal of Organic Agriculture
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• v.18 no.2
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• pp.245-255
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• 2010

The study was conducted to investigate the effects of organic fertilizers and mulches on the growth and $CO_2$ assimilation in MM.106 apple trees. Growth and $CO_2$ assimilation of MM.106 apple trees grown in a greenhouse were affected by the nutrient concentrations and carbon (C) and nitrogen (N) ratio in the raw materials of organic fertilizers and mulches. The optimum C:N ratios, which makes microorganism convert the organic N into the inorganic N, were obtained in the organic fertilizer, poultry litter, green compost, and grass clippings, resulting in increasing single shoot height, SPAD, and $CO_2$ assimilation. The SPAD and $CO_2$ assimilation were affected by the treatments 5 weeks after the treatments, and then the tree growth was affected by the treatments 6 weeks later. The most efficient tree growth and development were observed in the 10 to $15\;mg{\cdot}kg^{-1}$ of the inorganic N in a soil, and the N was strongly related to the tree growth and development.

• Korean Journal Plant Pathology
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• v.2 no.1
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• pp.22-30
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• 1986

The effect of powdery mildew infection on the $^{14}CO_2$ assimilation and metabolism of $^{14}C-$assimilates was studied with spring barley cultivars, susceptible Peruvian and adult-plant resistant Asse at the four-leaf stage. No consistent differences between Peruvian and Asse were revealed in $^{14}CO_2$ assimilation and metabolism of $^{14}C-$assimilates in healthy whole plants. In the two cultivars, $^{14}CO_2$ assimilation and translocation of assimilates decreased as the number of infected leaves increased. Despite the same infection intensity, $^{14}CO_2$ assimilation was less inhibited in Asse than Peruvian. Infection reduced the fixation of $^{14}CO_2$ in noninfected fourth leaves of Peruvian more severely than that of Asse. Infection of the lower 3 leaves also inhibited the incorporation of 14 C into carbohydrates such as fructose and glucose in noninfected fourth leaves and their translocation into leaf sheathes, the inhibitions being greater in Peruvian than Asse. In the infected third leaves, there was a reduction of 14 C-activity in carbohydrates, more $^{14}C-$labeled fructose and glucose being retained in Peruvian. The stimulation of $^{14}C-$organic acid synthesis in all plant organs was more pronounced in Peruvian than Asse. Powdery mildew markedly increased the incorporation of $^{14}C$ into amino acids in infected third and noninfected fourth leaves, but reduced their translocation to the leaf sheathes. A greater rise of $^{14}C-$ activity in some amino acids in the two leaves was found in Peruvian than Asse.

• Journal of Microbiology and Biotechnology
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• v.33 no.11
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• pp.1403-1411
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• 2023

Carbon dioxide (CO₂) is the most abundant component of greenhouse gases (GHGs) and directly creates environmental issues such as global warming and climate change. Carbon capture and storage have been proposed mainly to solve the problem of increasing CO₂ concentration in the atmosphere; however, more emphasis has recently been placed on its use. Among the many methods of using CO₂, one of the key environmentally friendly technologies involves biologically converting CO₂ into other organic substances such as biofuels, chemicals, and biomass via various metabolic pathways. Although an efficient biocatalyst for industrial applications has not yet been developed, biological CO₂ conversion is the needed direction. To this end, this review briefly summarizes seven known natural CO₂ fixation pathways according to carbon number and describes recent studies in which natural CO₂ assimilation systems have been applied to heterogeneous in vivo and in vitro systems. In addition, studies on the production of methanol through the reduction of CO₂ are introduced. The importance of redox cofactors, which are often overlooked in the CO₂ assimilation reaction by enzymes, is presented; methods for their recycling are proposed. Although more research is needed, biological CO₂ conversion will play an important role in reducing GHG emissions and producing useful substances in terms of resource cycling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.243-247
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• 2003

To examine ideal leaf types with higher $\textrm{CO}_2$ assimilates and different seed sizes, 12 soybean varieties were planted on the pot in a plastic house covered with glass. Leaf function based on stomatal conductance and $\textrm{CO}_2$ assimilation in soybean is different in seed size and leaflet shape. Mean $\textrm{CO}_2$ assimilation of a single leaf was 19.66 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$ and showed higher in small seed cultivars with narrow leaflet than that of small seeds with wide leaflet (18.29 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$), but within large seed groups, it was higher in wide leaflets (19.17 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$) than narrow leaflet cultivars (17.45 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$). In small seed and narrow leaflet cultivars, stomatal conductance ranged from 0.14 to 0.15 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$, while $\textrm{CO}_2$ assimilation ranged from 19 to 20 $\mu\textrm{molm}^{-2}\textrm{s}^{-1}$. The Photosynthetic rate was closely related to stomatal conductance, transpiration and water use efficiency.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.3
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• pp.268-274
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• 2010

The aim of our study was to investigate the interactive effects of container size and nutrient supply on plant growth, chlorophyll synthesis, transpiration, $CO_2$ assimilation, water use efficiency (WUE), and nutrient uptake of vinca plant (Catharanthus roseus). A complete experiment utilizing four concentrations of fertilizer and three volumes of containers was conducted. As the container size was increased, the plant height, leaf area, and dry weight of vinca significantly increased regardless of fertilizer level. The leaf area and dry weight of vinca were highly sensitive to the container size. However, the chlorophyll contents of vinca 20 days after the transplant significantly increased with decreasing container sizes and increasing fertilizer concentrations. Significant differences in transpiration and $CO_2$ assimilation occurred with the use of differentfertilizer solutions, but the highest values for transpiration and $CO_2$ assimilation were in plants grown in the 15 cm-diameter containers. The highest water use efficiency was observed in the plants grown in 10 cm-containers with 4 dS/m of fertilizer, and there were no significant differences in WUE values among container sizes with fertilizer concentrations of 0, 1, or 2 dS/m. No significant difference in nutrient uptake was observed among the fertilizer levels or among the container sizes. However, at a fertilizer concentration of 4 dS/m, the uptake of several nutrients, including N, P, K, Ca, Mg, B and Fe, was higher in small containers than in larger ones.

• Journal of Environmental Health Sciences
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• v.23 no.1
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• pp.1-7
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• 1997

We investigated the influence of various known sterilization methods on atrazine assimilation. The present study was designed to investigate the effect of autoclaving, sodium azide and mercuric chloride treatment on the assimilation of atrazine in soil and sediment. The sterilization reactor treated with sodium azide resulted in $^{14}CO_2$ generation and atrazine was rapidly disappeared from reactor through chemical reaction with sodium azide. These findings seem to indicate that sodium azide sterilization is not recommended for atrazine studies. In sample reactors autoclaved or treated with mercuric chloride, $^{14}CO_2$ generation was not detected and most of the disappeared atrazine was found to exist as hydroxyatrazine. These results suggested that autoclaving or mercuric chloride treatment could be effective sterilization methods. However, chemical properties(pH and redox potential) of soil and sediment were altered by any of the sterilization methods applied. So it was suspected that these altered properties could affect distribution and mineralization of atrazine in soil and sediment. In addition, both autoclaving and mercuric chloride treatment have altered $K_d$ values of hydroxyatrazine more significantly than those of atrazine. Consequently, although autoclaving and mercuric chloride treatment are effective sterilization methods, one must be careful in using them in practice as these methods may cause chemical degradation of both of atrazine and its metabolites and changes in chemical properties of soil and sediment. In conclusion, careful assessment of sterilization methods must be made for the degradation studies of chemicals in soil and sediment in order to minimize possible undesirable chemical degradation of sample and/or changes in physico-chemical properties of soil and sediment by the selected sterilization methods.

• Atmosphere
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• v.22 no.4
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• pp.415-427
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• 2012

$CO_2$ is the most important trace gas related to climate change. Therefore, understanding surface carbon sources and sinks is important when seeking to estimate the impact of $CO_2$ on the environment and climate. CarbonTracker, developed by NOAA, is an inverse modeling system that estimates surface carbon fluxes using an ensemble Kalman filter with atmospheric $CO_2$ measurements as a constraint. In this study, to investigate the capability of CarbonTracker as an analysis tool for estimating surface carbon fluxes in Asia, an experiment with a nesting domain centered in Asia is performed. In general, the results show that setting a nesting domain centered in Asia region enables detailed estimations of surface carbon fluxes in Asia. From a rank histogram, the prior ensemble spread verified at observational sites located in Asia is well represented with a relatively flat rank histogram. The posterior flux in the Eurasian Boreal and Eurasian Temperate regions is well analyzed with proper seasonal cycles and amplitudes. On the other hand, in tropical regions of Asia, the posterior flux does not differ greatly from the prior flux due to fewer $CO_2$ observations. The root mean square error of the model $CO_2$ calculated by the posterior flux is less than the model $CO_2$ calculated by the prior flux, implying that CarbonTracker based on the ensemble Kalman filter works appropriately for the Asia region.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.556-561
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• 1995

Persisent circadian rhythms in carbon assimilation, stomatal conductance and soluble carbohydrate concentration were investigated during grain filling period in rice plant transferred from a natural photoperiod to constant conditions. A weak rhythm in photosynthesis, measured as carbon assimilation, and stomatal opening, as conductance to water vapor, with a period of approximately 24-hours, occurred under constant condition. Carbon assimilation and stomatal conductance reached maximum values near noon and minimum values near midnight during the early stage (until 72-hour) after transferring to constant condition, and then the amplitude and phase were changed slowly, the rhythms with little damping, reaching maximum values near midnight and minimum values near noon during 96~120-hours after transferring. However, photosynthesis in plants grown for 14days after anthesis under constant moderate light(day and night) did not oscillated in constant condition unlike plants grown under a cycle of light and darkness. These phenomenon was observed in soluble carbohydrate concentration in flag leaves as well. Evidences from several approaches indicate that endogenous rhythms of $CO_2$ assimilation, stomatal conductance and soluble carbohydrate concentration are closely couped with each other and particularly important to plants, which depend on the natural day-night cycle as a external signal.