• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.39-51
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• 1991

The primary production of phytoplankton in oyster farming bays were seasonally measured by $^{14}C$ method in Hansan-Koje Bay and Kamagyang Bay for one year period. In Hansan-Koje Bay, mean daily prima production was $0.52gC/m^2/day\;(0.22{\~}1.02gC/m^2/day)$, and it was relatively high in summer and low in winter. Annual primary production was estimated to be $189gC/m^2/yr.$. Mean chlorophyll a content was $1.70mg/m^3$, and it was relatively high in summer. In Kamagyang Bay, mean daily prima production was $0.91gC/m^2/day(0.11{\~}3.61gC/m^2/day)$. and it was maximum in summer and minimum in fall. Annual primary production was estimated to be $334gC/m^2/yr$. Mean chlorophyll a concentration was $2.34mg/m^3$, and it was maximum in summer and relatively high in winter. Considering the water area of the two osyter farming bays, annual carbon production by phytoplankton were 9,450 ton in Hansan-Koje Bay and 37,000 ton in Kamagyang Bay. In general pattern of primary production in these bays, high production occurs in summer with increasing trend since spring.

• Proceedings of the Microbiological Society of Korea Conference
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• 2006.05a
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• pp.144-144
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• 2006

• Korean Journal of Agricultural Science
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• v.10 no.2
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• pp.257-262
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• 1983

Dimension analysis was uesd to estimate biomass and net primary production (NPP) in a 35-year-old red pine (Pinus resinosa Ait.) plantation in central Wisconsin, U. S. A.. Total above ground biomass was estimated at $97.3Mg\;ha^{-1}$. Organic matter was distributed in the red pine stand as follows : bolewood 67.8%, live branches 15.4%, foliage 8.4%, bole bark 6.1%. Net primary production was estimated at $11.5Mg\;ha^{-1}yr^{-1}$ and was distributed : bolewood 30.4%, foliage 25.2%, branches 36.5%, bole bark 2.6%. There were differences in total biomass and proportion of biomass components when using the three equations. These differences are due to : a) difference in bolewood specific gravity and b) the effect of thinning on the form factor.

• Journal of Korean Society of Forest Science
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• v.71 no.1
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• pp.74-81
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• 1985

Dimension analysis was used to estimate biomass and net primary production(NPP) in a 36-year-old Japanese red pine (Pines densiflora S. et Z.) natural forest in Kangwondo. Best estimation was made by the equation model of $Wt=aD^bH^c$ where Wt is weight in kg, D is DBH in cm, and H is total tree height in m. Total aboveground biomass was estimated at 198.82 t/ha. Organic matter was distributed in the Japanese red pine stand as follows ; bolewood 68.8%, live branches 16.5%, bolebark 5.4%, foliage 4.6%, dead branches 3.7%, and cones 0.6%. Net primary production was estimated at 15.87 t/㏊/yr and was distributed: bolewood 44.5%, live branches 30.9%, foliage 14.1%, current twig 7.1%, and bolebark 3.3%. Leaf efficiency was estimated at 1.876. The power equation for biomass and IVPP yielded similar results as the results for Pines densiflora in Japan.

• Journal of Microbiology and Biotechnology
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• v.24 no.4
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• pp.507-521
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• 2014

A phase variation has been reported in an entomopathogenic bacterium, Xenorhabdus nematophila. Compared with a wild-type primary form, a secondary form usually loses several physiological and biochemical characters. This study showed that the phase variation of X. nematophila caused a significant alteration in its immunosuppressive activity and subsequent entomopathogenicity. A secondary form of X. nematophila was detected in laboratory colonies and exhibited significant differences in dye absorption and entomopathogenicity. In addition, the secondary form was different in its production of eicosanoid-biosynthesis inhibitors (EBIs) compared with the primary form of X. nematophila. Production of oxindole and p-hydroxypropionic acid was significantly reduced in the culture broth of the secondary form of X. nematophila. The reduced EBI production resulted in significant suppression in the inhibitory effects on cellular nodule formation and phenoloxidase activity. Culture broth of the primary form of X. nematophila enhanced the pathogenicity of Bacillus thuringiensis ( Bt) significantly more than the culture broth of the secondary form. Furthermore, this study developed a highly efficient "Dual Bt-Plus: to control both lepidopteran insect pests Plutella xylostella and Spodoptera exigua, by mixing two effective Bt strains along with the addition of potent bacterial metabolites or 100-fold concentrated X. nematophila culture broth.

• Journal of Ecology and Environment
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• v.41 no.12
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• pp.328-335
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• 2017

Background: Some researchers have attempted to evaluate the ecological function of various additional services, away from the main point of view on the timber production of Korean forests. However, basic data, evaluation models, or studies on the absorption of air pollutants related to major plant communities in Korea are very rare. Therefore, we evaluated the functional value of the forest ecosystem in Gongju-city. Plantation manual for air purification, supplied from the Ministry of Environment in Japan, was referred to process and method for assessment of air pollutant absorption. Results: Gross primary production was calculated about average 18.2 t/ha/year. It was a relatively low value in forests mixed with deciduous broad and evergreen coniferous compared to pure coniferous forest. Net primary production was the highest value in deciduous coniferous and was the lowest value in mixed forest with deciduous broad and evergreen broad. And the mean sequestration amount of each air pollutant per unit area per year assessed from gross primary production and concentration of gas was the highest with 75.81 kg/ha/year in $O_3$ and was 16.87 and 6.04 kg/ha/year in $NO_2$ and $SO_2$, respectively. In addition, total amounts of $CO_2$ absorption and $O_2$ production were 716,045 t $CO_2$/year and 520,760 t $O_2$/year in all forest vegetation in Gongju-city. Conclusions: In this study, we evaluated the absorption ability of air pollutant in 2014 on forest in Gongju-city area. Gongju-city has the broad mountain area about 70.3%, and area of deciduous broad leaves forest was established the broadest with 47.4% of genus Quercus. Pg was calculated about average 18.2 t/ha/year. The mean sequestration amount of each air pollutant per unit area per year assessed from Pg and $C_{gas}$ was the highest with 75.81 kg/ha/year in $O_3$ and were 16.87 and 6.04 kg/ha/year in $NO_2$ and $SO_2$, respectively. Absorption rates of $O_3$, $NO_2$, and $SO_2$ were the highest in evergreen coniferous forest about $14.87kgO_3/ha/year$, $3.30kgNO_2/ha/year$, $1.18kgSO_2/ha/year$, and the lowest were $5.95kgO_3/ha/year$, $1.32kgNO_2/ha/year$, and $0.47kgSO_2/ha/year$ in deciduous broad forest. In conclusion, it was evaluated that Japanese model is suitable for estimating air pollutants in Japan to Korean vegetation. However, in Korea, there is a very limited basic data needed to assess the ability of forests to absorption of air pollutants. In this study, the accuracy of a calculated value is not high because the basic data of trees with similar life form are used in evaluation.

• Journal of Wetlands Research
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• v.14 no.4
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• pp.503-518
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• 2012

Models estimating carbon budget at land surface are mainly interested in vertical flux of carbon. On the other hand, studies on horizontal flux are obviously lacked to confirm that relationship between the hydrological flux of organic carbon discharged from catchment and terrestrial carbon production, a relation between Total Organic Carbon(TOC) and Gross Primary Production(GPP) tried analysis through cross correlation. The best correlation structure is correlation between GPP and TOC of flow-weighted mean concentration from watershed without delay. Furthermore, cross correlation analysis was performed by consider periodicity. The correlation between TOC and GPP in summer was similar to correlation without periodicity. Therefore, correlation between GPP and TOC was most regulated by the correlation between GPP and TOC at summer. As a result, the vegetation carbon and organic carbon from watershed is recognized a close relationship on the seasonal. Therefore, future research is correlation analyzing between vegetation variables according season, GPP and TOC, we are expected to use quantitative understanding that horizontal flux flow of carbon from the surface.

• Journal of Korean Society on Water Environment
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• v.34 no.6
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• pp.579-590
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• 2018

The lakes' metabolism bears important information for the assessment of the carbon budget due to the accumulation or loss of carbon in the lake as well as the dynamics of the food webs through primary production. A lake-scale metabolism is evaluated by Gross Primary Production (GPP), Ecosystem Respiration (R), and Net Ecosystem Production (NEP), which is the difference between the first two values. Methods for estimating GPP and R are based on the levels carbon and oxygen. Estimation of carbon is expensive because of the use of radioactive materials which requires a high degree of proficiency. The purpose of this study was to estimate Lake Daecheong ecosystem metabolism using high frequency water temperature data and DO measurement sensor, widely utilized in the field of water quality monitoring, and to evaluate the possibility of using the application method. High frequency data was collected at intervals of 10 minutes from September to December 2017 by installing a thermistor chain and a DO sensor in downstream of Daechung Dam. The data was then used to estimate GPP, R and NEP using the R public program LakeMetabolizer, and other metabolism models (mle, ols, kalman, bookkeep). Calculations of gas exchange coefficient methods (cole, crusius, heiskanen, macIntyre, read, soloviev, vachon) were compared. According to the result, Lake Daecheong has some deviation based on the application method, but it was generally estimated that the NEP value is negative and acts as a source of atmospheric carbon in a heterotrophic system. Although the high frequency sensor data used in this study had negative and positive GPP and R values during the physical mixing process, they can be used to monitor real-time metabolic changes in the ecosystem if these problems are solved.

• Korean Journal of Ecology and Environment
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• v.40 no.3
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• pp.419-430
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• 2007

Physiochemical factors, phytoplankton biomass (Chl ${\alpha}$) and primary productivity were investigated seasonally in the three lakes of Dongbok, Juam, and Yeongsan during April 2004${\sim}$March 2006. Microphytoplankton dominated (>60%) in Dongbok lake, and phytoplankton biomass was high in the upper area, especially during April 2004, whereas they were high in the lower area during June 2004. In Juam lake, the high phytoplankton biomass in April 2004 was contributed by nanophytoplankton. In Yeongsan lake, chlorophyll a was high in August with high contribution of nanophytoplankton. Primary production was highest in Dongbok lake, and then followed by Yeongsan and Juam lakes. Regression analysis in Dongbok take showed that Chl ${\alpha}$ and primary production had close relations with secchi depth. In Juam lake, phosphate were correlated with the Chl ${\alpha}$, while temperature and TN was correlated with primary production in the lower area. In Yeongsan lake, Chl ${\alpha}$ have positively correlation with TN/TP. Primary production in the upper have high relationship with secchi depth, however, in the lower have high relationship with turbidity. Linear regression analysis showed that nutrients of nitrogen and phosphorus should be reduced for the protections in Juam and Dongbok lakes. We suggested that suspended solids and phytoplankton growth related to turbidity are needed to manage in Yeongsan lake.

• Nuclear Engineering and Technology
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• v.37 no.6
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• pp.537-556
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• 2005

A primary-pipe rupture accident is one of the design-basis accidents of a High-Temperature Gas-cooled Reactor (HTGR). When the primary-pipe rupture accident occurs, air is expected to enter the reactor core from the breach and oxidize in-core graphite structures. This paper describes an experiment and analysis of the air ingress phenomena and the method fur the prevention of air ingress into the reactor during the primary-pipe rupture accident. The numerical results are in good agreement with the experimental ones regarding the density of the gas mixture, the concentration of each gas species produced by the graphite oxidation reaction and the onset time of the natural circulation of air. A hydrogen production system connected to the High-Temperature Engineering Test Reactor (HTTR) Is being designed to be able to produce hydrogen by themo-chemical iodine-Sulfur process, using a nuclear heat of 10 MW supplied by the HTTR. The HTTR hydrogen production system is first connected to a nuclear reactor in the world; hence a permeation test of hydrogen isotopes through heat exchanger is carried out to obtain detailed data for safety review and development of analytical codes. This paper also describes an overview of the hydrogen permeation test and permeability of hydrogen and deuterium of Hastelloy XR.