• Korean Journal of Environmental Biology
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• v.38 no.2
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• pp.299-307
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• 2020

This study reported on the phytoplankton community and seasonal changes in the Seoul passage section and downstream in the Han River in 2012. Field samples were collected monthly from the upper (Paldang), middle (Cheongdam), and downstream(Seongsan) areas of the Seoul passage section. Water temperature, DO, pH, and conductivity were measured at each station. All environmental factors measured were recorded similarly at the three stations. The water temperature ranged from 2 to 30℃ and the dissolved oxygen ranged from 4.8 to 9.1 mg L^-1, showing typical patterns of temperate regions. The phytoplankton cell concentrations ranged from 990 cells mL^-1 (Paldang, December) to 2.9×10⁴ cells mL^-1 (Seongsan, March), and the chlorophyll-a content showed similar patterns to the cell numbers. The phytoplankton community was comprised of 75 genera and 95 species, including 37 diatoms, 29 Chlorophyta, 11 cyanobacteria, and two dinoflagellates. The number of species that appeared seasonally varied greatly, from nine species (Paldang, May) to 35 species (Cheongdam, December). Diatoms were the most dominant in all stations and seasons, except in summer. In contrast, chlorophytes and cyanobacteria showed sporadic high numbers in the summer and fall seasons. Four diatoms Stephanodiscus hantzschii f. tenuis, S. hantzschii, Fragilaria sp., and Aulacoseira spp., a chlorophyte Actinastrum hantzschii, and a cyanobacterium Microcystis sp. were each present in proportions greater than 10%. This study provides fundamental data from phytoplankton communities and environmental factors in the Han River for understanding water quality for long-term environmental monitoring.

• Journal of Korea Soil Environment Society
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• v.2 no.2
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• pp.9-24
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• 1997

Surfactant-aided in situ soil flushing has been proposed as an alternative for the expensive and time consuming 'pump and treat' technology in remediation of contaminated soil and groundwater Injected surfactants can effectively solubilize contaminants sorbed to the soil matrix or nonaqueous phase liquids(NAPLs) in residual saturation. The contaminants solubilized in groundwater are recovered and treated further. The theoretical background of the technology and the results of the field operations, mostly in the US. were summarized. In addition, the factors crucial to the successful application of the technology were discussed. Cost analyses and technical limitations in current applications were also discussed. In conclusion, it is likely that in situ surfactant flushing become a viable option for soil remediation in limited cases. Currently, further advances with respect to operation cost and to treatment efficiency are required for more extensive application of the technology. However, the current trends in soil remediation, specially the growing emphasis on risk based corrective action and natural attenuation, will increase the competitiveness of the technology. For example, removal of easily washable contaminants by short term soil flushing followed by long term monitoring and natural attenuation can greatly reduce the operation cost and time.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.1
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• pp.49-53
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• 1979

Effects of temperature and light intensity on photosynthesis, respiration and chlorophyll content of ginseng (Panax ginseng C. A. Meyer) were as follow. 1. Optimum light intensity for apparent photosynthesis at $25^{\circ}C$ was 25Klux($1.35mgCO_2/dm^2{\cdot}hr$) for two years old ginseng grown in pot and 30Klux($1.94mgCO_2/dm^2{\cdot}hr$) for the six years old palmate cut leaves. Optimum temperature at 25Klux was $15^{\circ}C$ ($1.40mgCO_2$) for the 2 years old and 20 to $22^{\circ}C$ ($2.03mgCO_2$) for the 6 years old. 2. Dark respiration increased almost linearly with the increase of air temperature till $25^{\circ}C$ (2.6times between $16^{\circ}C$ to $25^{\circ}C$ for the 6 years old and 1.8 times between $15^{\circ}C$ to $25^{\circ}C$ for the 2 years old). Dark respiration was 11.1 % of net photosynthesis at $16^{\circ}C$, 17.8% at $25^{\circ}C$ for the 6 years old and 40% at $15^{\circ}C$, 64.7% at $25^{\circ}C$ for 2 years old. 3. Stomata appeared only in abaxial surface (lower epidermis) and stomatal frequency was $37per\;mm^2$. 4. Above results together with other informations quoted here strongly suggest that air temperature is much better criteria than light intensity for the improvement of shading roof material and shading construction. That is to promise maximum light intensity unless air temperature is above $25^{\circ}C$.

• Journal of Aquaculture
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• v.4 no.2
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• pp.111-128
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• 1991

In puan area the environmental surveys were carried out at two farms of hard clam, Meretrix lusoria from April 1987 to November 1978 in order to know heather the farm environments could be rehabilitated for the cultivation of hard clam or not. The range of temperature of surface seawater was $10.7{\~}27.4^{\circ}C$, pH $7.6{\~}8.2$, salinity $22.3{\~}30.3$ ppt, COD $0.20{\~}4.71\;mg/{\ell}$, sulfide $0.04{\~}0.22\;{\mu}g-at./{\ell}$, suspended solid $34.8{\~}199.3\;mg/{\ell}$ chlorophyll a $3.71{\~}49.02\;mg/m^3$, TIN $2.01{\~}24.47\;{\mu}g-a5./{\ell}$, phosphate $0.60{\~}11.03\;{\mu}g-at./{\ell}$ and silicate $4.04{\~}476.36\;{\mu}g-at./{\ell}$. The range of temperature of substratum (bottom soil) was $14.2{\~}29.7^{\circ}C$, pH $8.3{\~}9.5$, water content of substratum was $0.28{\~}0.49\;mg/g$ dried mud, COD $2.80{\~}50.94\;mg/g$ dried mud, total organic matter $1.05{\~}1.97\%$ concentration of total Kjedhal nitrogen $31.9{\~}194.9\;{\mu}g./{\ell}$ dried mud, and sulfide $0.032{\~}0.133\;mg/g$ dried mud. Fine sand was dominant ranging over $92{\~}95\%$ and silt and clay was $2.8{\~}8.1\%$ of the composition of substratum. Some residual agricultural chemicals, ${\alpha},\;{\beta},\;{\gamma}$-BHC, heptachlor, heptachlor-epoxide, aldrin, DDE, DDT and dieldrin were detected in hard clams collected from Puan areas. Especialy, more chemical were detected during the period of rainfalls. From above results, it is considered that the hard clam frams were not yet recovered from deteriorated conditions for aquaculture.

• Journal of Korean Society of Forest Science
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• v.58 no.1
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• pp.17-22
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• 1982

During the two-years(1979 to 1980) fertilization trial on 4-year-old chestnut tree plantations, total insolation was diminished in 1980 because of unseasonable weather. In every fertilization treatment plot, especially in the NPK-fertilized plot with magnesium, growth of trees and yield of chestnuts have been increased significantly. The results obtained are as follows: 1) The growth in the NPK-fertilized plot with boron and magnesium was 20 percent higher than in plots fertilized with NPK alone. 2) Although there was some frost damage to trees on November 14, 1979, the 1979 weather was otherwise normal and daily insolation averaged 7 hours from June through september, The 1979 fertilization indices for chesnut yield were 167 for NPK with boron and 207 for NPK with magnesium, as compared with the base index of 100 for NPK alone. 3) In 1980, the second year of the fertilization trial, unseasonable weather decreased the average daily insolation from June through September to 3.8 hours. Under such conditions, the fertilization indices for chestnut yield were 620 for NPK with boron and 741 for NPK with magnesium, and Boron, as compared to the base index of 100 for NPK alone; i.e. the yields of plots treated with NPK and magnesium were 21 percent higher than for plots with NPK and boron and 7 times the yields for plots with NPK alone, But in the trial plot of NPK, yield of chestnut in 1980 decreased compared with 1979, 4) All test plots had natural magnesium levels lower than 0.8me/100gr., and the treatments with NPK and magnesium would have been less apparent on soils with higher magnesium level. The spectacular effects of treatment with NPK and magnesium during periods of low insolation may result from increased chlorophyll production and corresponding increases in active carbon assimilation, which should play an important role in carbohydrate formation.

• Korean Journal of Medicinal Crop Science
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• v.9 no.1
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• pp.26-32
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• 2001

The contents of chemical components such as total nitrogen, total amino acid and vitamin C were somewhat higher in $N_2$ gas treatment at $10^{\circ}C$ for 3 hours than those of other treatments. However, the contents of tannin and chlorophyll were slightly lower than that in the other treatments. The content of ${\gamma}-Aminobutyric$ acid with $N_2$ gas treatment was higher $1.5{\sim}6$ times with values of $51{\sim}205mg/100g$ than in control (35mg/100g). The scores of sensory test was not different between $N_2$ gas treatment for 3 hours and control. The contents of chemical components such as total nitrogen, total amino acid including theanine and caffeine were slightly higher in $N_2$ gas treatment at $20^{\circ}C$ for 3 hours than those of other treatments. However, the contents of tannin and vitamin C were slightly lower than those of other treatment. The content of GABA in tea leaves treated with $N_2$ gas was higher $2.5{\sim}7$ times with values of $85{\sim}225mg/100g$ than in control (35mg/100g). The sensory test was lower in $N_2$ gas treatment($76.3{\sim}78.1$ point) than in control(80.4 point). The contents of chemical components were not different between $N_2$ gas treatment at $30^{\circ}C$ for 3 hours and control. Whereas the contents of chemical components were somewhat lower in $N_2$ gas treatment for 1 hour and 5 hours than in control. The content of GABA in tea leaves treated with $N_2$ gas was higher $3{\sim}7$ times with values of $115{\sim}217mg/100g $than in control(35mg/100g). The sensory test was lower in $N_2$ gas treatment ($74.3{\sim}78.4$ point) than in control(80.4 point). Consequently, tea mading within 5 time $N_2$ gas treatment at $10^{\circ}C$ or 3 time $N_2$ gas treatment at 20, $30^{\circ}C$ after plucking was considered to be the best green tea in terms of functional nature as well as taste nature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.6008-6014
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• 2013

This study aimed to understand seasonal variation of physico-chemical factors and biomass of size-fractionated phytoplankton at Ulsan seaport during the period from February 2007 to November 2009. Water temperature, salinity, dissolved oxygen (DO), pH, chemical oxygen demand (COD) and total suspended solid (TSS) varied in the range of 8.94-$24.26^{\circ}C$, 25.06-34.54 psu, 4.30-10.73 mg/L, 7.97-8.53, 0.66-40.70 mg/L and 57.4-103.3 mg/L, respectively. These factors showed no clear spatial variation unlike spatial pattern of inorganic nutrients and total chlorophyll-a (chl-a) concentration as biomass. Concentration of phosphate, nitrate and silicate ranged from 0.01 to 3.03 ${\mu}M$, 0.05 to 21.62 ${\mu}M$, and 0.01 to 27.82 ${\mu}M$, respectively, with 2 times higher concentration at inner stations than that at outer stations during the study period. Within the range of total chl-a concentration (0.36-7.11 ${\mu}gL^{-1}$), higher concentration (avg. 1.88 ${\mu}gL^{-1}$) of total chl-a were observed at inner stations compared to that (avg. 0.90 ${\mu}gL^{-1}$) at outer stations. Micro-sized phytoplankton dominated total biomass of phytoplankton in spring (34.0-81.2%), summer (35.1-65.6%) and winter (3.9-62.0%). Nano- and pico-sized phytoplankton contributed 58.2-74.5% and 22.4-38.2% to total biomass of phytoplankton in autumn, respectively. However, contribution in biomass of size-fractionated phytoplankton to total phytoplankton biomass showed no clear difference between inner and outer stations. Consequently, these results indicated that spatio-temporal distribution of phytoplankton biomass at Ulsan seaport was dominated by micro-phytoplankton (avg. 52.3%) during the study period except autumn, which was closely dependent on the concentration of inorganic nutrients (p<0.05).

• Journal of Korean Society of Forest Science
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• v.90 no.3
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• pp.306-313
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• 2001

The objectives of this study were to understand the physiological responses and resistance of red pine trees to ozone exposure in relation to nitrogen and phosphorus fertilization. Potted one-year-old seedlings of Pinus densiflora S. et Z. were exposed in an open-top chamber(OTC) to ozone at concentration of 0.12ppm for 3 hours daily for eight weeks with or without N and P fertilization alone or in combination. The OTC had dimensions of 2.0m in height and 2.5m in diameter, and the air in a control chamber was filtered with activated charcoal to maintain the ozone concentration below 0.02ppm. After eight weeks of ozone exposure, none of the seedlings showed any symptoms of visible injury on leaves. The seedlings fertilized with N and P in a control chamber showed 22 to 95% increase in total dry weight, and similar fertilizer effect was also noticed in an ozone chamber. Ozone treatment did not decrease the total dry weight, but increased shoot/root ratio by 14.5%. Ozone treatment increased sucrose content in the leaves by 23%, but decreased sucrose content in roots by 20% regardless of N or P application. Starch content in the leaves was not affected by either ozone or fertilizer. However, starch content in the roots was decreased by 41% by ozone treatment. Chlorophyll content in the leaves was increased by 70% by N application, but was not affected by ozone treatment. Nitrogen and P fertilization stimulated net photosynthesis by 80% in a control chamber, but stimulatory effect of N and P on net photosynthesis was 22.3% less in an ozone chamber. Net photosynthesis of the seedlings with no fertilization was not affected by ozone treatment. Based on the observed interactions between N, P, and ozone, it was concluded that the stimulatory effect of fertilization on growth of Pinus densiflora would be decreased by ozone treatment, but fertilization would increase resistance to ozone by re-allocation of increased carbohydrates.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.2
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• pp.102-114
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• 2013

The basin of Lake Shihwa is one of highly industrialized region of Korea and a current environmental issue of study area is the operation of tidal power plant (TPP) to improve water quality. The application of water quality index (WQI) which integrates five physiochemical parameters (transparency, DO, DIN, DIP and chlorophyll-a) of water quality in Lake Shihwa and outer sea during 2011~2012 were performed not only to evaluate the spatial and temporal distribution of the water quality but also to assess the effect of water quality improvement by the operation of tidal power plant. The higher WQI values were observed in monitored sites near the industrial complexes in Lake Shihwa and the outfall of wastewater treatment plants (WWTPs) in outer sea. This indicates that the quality of seawater is influenced by diffuse non-point sources from industrial, municipal and agricultural areas in Lake Shihwa and by point sources from the effluence of municipal and industrial wastewater throughout WWTPs in outer sea. Mean WQI value decreased from 53.0 in 2011 to 42.8 in 2012 of Lake Shihwa. Water quality has improved significantly after TPP operation because enhancement of seawater exchange between Lake Shihwa and outer sea leads to improve a hypoxic condition which is primarily a problem in Lake Shihwa. Mean WQI of outer sea showed similar values between 2011 and 2012. However, the results of hierarchical cluster analysis and the deterioration of water quality in summer season indicate that the operation of tidal power plant was not improved the water quality in the upper most area of Lake Shihwa. To successfully improve overall water quality of Lake Shihwa, it is urgently necessary to manage and reduce of non-point pollution sources of the basin of Lake Shihwa.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.4
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• pp.257-263
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• 2016

Recently, an interest has developed in the use of whole green grains as functional food materials. The present study was conducted to provide the baseline data for the stable production of whole green grains in 20 cultivars of wheat by investigating the greenness of grain with maturation (from $20^{th}$ to $41^{st}$ day after heading, at an interval of 3 days). On the $20^{th}$ day after heading, the grains were dark green with a wrinkled long-oval shape. After the $35^{th}$ day of heading, the grains turned almost yellow with an oval shape. Their redness ('a' value of chromaticity) increased from the $20^{th}$ to $41^{st}$ days after heading, indicating a negative value up to the $32^{nd}$ day after heading. A significant decrease in their chlorophyll content was observed with maturation. The yield of whole green wheat grain (including greenish yellow grain) was the highest from the $32^{nd}$ to $35^{th}$ after heading. Therefore, we concluded that the optimal harvesting period for whole green wheat grain was from the $32^{nd}$ to $35^{th}$ day after heading. The heading time of various cultivars ranged from April 28 to May 5, the time of Jopummil cultivar grew the fastest among them, such as Gurumil, Alchanmil, but Dahongmil got the latest in heading time. The greenness of seven cultivars (Jeokjungmil, Keumkangmil, Jogyeongmil, Jopummil, Baekjungmil, Yeonbaekmil, and Milseongmil) was relatively higher than that of the others. The yield of greenish whole grain was relatively high in six cultivars (Alchanmil, Baekjungmil, Eunpamil, Yeonbaekmil, Dahongmil, and Urimil). Based on their greenness and yield, the Baekjungmil and Yeonbaekmil cultivars have been considered to be optimal for the production of whole green wheat grain.