• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.181-187
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• 2005

For 4 years (2000 ${\sim}$ 2003), annual fluctuations of standing crops of cyanobacteria and physicochemical factors were examined at five sites from Bridge of Seungsoo to Bridge of Seungsan in the lower part of Han River. The cyanobacterial abundance (ND to 4,167 cells $mL^{-1}$) was strongly decreased during the heavy rains in every year. During the similar periods in 2003, cyanobacteria hardly observed, and comprised below of 10 percentage of total phytoplankton. In the period of little cyanobacteria, some green algae and diatom dominated the phytoplankton community, while the concentration of chlorophyll a has not largely change. These results indicate that heavy frequent precipitation strongly limited the growth of cyanobacteria, and lead an algal succession by the appearance of new algal groups.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.71-77
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• 1999

Phytoplankton communities were investigated 13 times during the period from November, 1995 to December, 1996 in the coastal area of Kori. A total of 162 taxa (including unidentified species) were observed； 120 diatoms, 3 silicoflagellates, 34 dinoflagellates, 2 euglenoids, 1 chlorophyte and 2 unidentified microflagellates. A diatom species, Skeletonema costatum (Greville) Clove dominated all the year round. The standing stocks of phytoplankton ranged from 94 cells/ml in August to 1059 cells/ml in July. The peaks of standing stocks occurred in February and July. The effects of thermal effluent to the phytoplankton communities changed seasonally and might affect increasing the standing stocks where about 1 ∼ 3 km from the discharge of Kori Nuclear Power Plant in autumn and winter. But the effects of thermal effluent must be negative in summer.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.232-241
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• 2012

The seasonal changes in phytoplankton species composition, standing crops, dominant species, species diversity and physico-chemical characteristics in the Unmun dam were studied, from August, 2009 to April, 2010. The phytoplanktons of a total of 121 taxa were identified, the composition of phytoplankton community was characterized by a green algae and diatoms, and the quantity composition of standing crops was dominated by diatoms and dinophyceae. The diatoms Aulacoseria granulata and blue-green alga Anabaena planktonica in Summer, Peridinium voltzii in Autumn and Asterionella formosa in Winter to Spring were, especially, prominent. The seasonal changes of the biomass varied from 578 cells $mL^{-1}$ to 12,938 cells $mL^{-1}$, and the maximum algal density was observed in April, Asterionells formosa contributed to 88% of the total cell numbers. The species diversity and richness were highest during autumn, and dominance index was highest in the spring season.

• Journal of Korea Foresty Energy
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• v.22 no.1
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• pp.49-57
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• 2003

This study was carried out with Urich II method for estimating the aboveground biomass of 30 years old Chamaecypris obtuse plantation in Jinhae, Cyeongnam province, in order to solve problems of exhaustion of many time and manpower in field survey for estimating biomass of stands. The results were summarize as follows; Total aboveground biomass production of stands was 137.3ton/ha, which was 71.8% of stem, 15.4% of branch and 12.8% of leaf. Foliage biomass of stands was maximized on the 9.2~11.2m of total height. The ratio of biomass for each part of tree in Chamaecypris obtusa plantation was in order of, stem, branch and leaf in dominant and co-dominant tree, and was stem, leaf and branch in recessive tree. drying ratio by components were ranged 47.3~49.2% of stem, 48.8~52.9% of branch, 39.2~40.8 of leaf and 0.78%~0.89% of died branch. Specific gravity by sample tree was 0.49~0.53 range and there was not significantly different among sample tree.

• Korean Journal of Ecology and Environment
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• v.37 no.3 s.108
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• pp.263-271
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• 2004

To collect the basic ecological information about the microbial food webs in eutrophic water system with different residence time, the monthly variation of bacterioplankon (bacteria and small-sized cyanobacteria) and nanoplankton (phytoplankton and protists) were examined from December 2000 to September 2001. Kyungan stream is shorter in resident time (ca.5.4 d) than Seokchon reservoir (ca.72 d), even though they showed the same pattern in precipitation. With the basic environments, we examined the biomass (standing crops and its carbon content) of each plankton collected from the surface water. Large-sized planktons flourished in the time of low temperature, while small planktons were in the time of the high temperature period. Especially, in the Kyungan stream with much disturbance by rainfall and outflow, high diversity showed in term of species and cell morphology, compared to that of Seokchon lake. The time-lag relationship remarkably showed between phytoplankton and bacteria in Seokchon reservoir, and between protists and bacteria in Kyungan stream, respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.2
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• pp.35-45
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• 1996

In order to investigate the possibility of treating nightsoil sludge, the growth trend experiments with vermicompsting was performed and the stability of worm castings was evaluated by the analysis of minerals according to growth periods. Survival rate(SR) of earthworms decreased as earthworms grow up to 7 weeks. The growth period of the earthworms could be classified into two phases on the basis of the ratios of cast to feed ingested(ID). The growth period of the earthworms up to 3 weeks, the high percentage of dry weight of feed ingested(ID) is mainly utiliz-ed to an increase in fresh weight of earthworms, and after the 3 weeks, it is utilized to cast production in this experiment, respectively. The highest values of increasing rate(IR) and biomass of the earthworms(BE) were obtained at 3 weeks and those were 10.59mg/day and 14.48g, respectively. Between the increasing rate(IR) and biomass of the earthworms(BE), a highly positive correlation coefficient(p<0.001) ap-peared. The highest values of biomass of the earthworms(BE) and cast production(CW) were obtained at 3 and 7 weeks, respectively. All the concentrations of minerals except calcium(Ca) in worm castings was lower than the values in nightsoil sludge. It was considered that the major portion of minerals in nightsoil sludge may have been retained in the bodies of earthworms. And these values were lower than the regulated levels in organic fertilizers that the regula-tion standards. In conclusion, the worm castings are very stable for the use as soil conditioner or organic fertilizers.

• Journal of Korean Society of Forest Science
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• v.85 no.3
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• pp.443-452
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• 1996

A study has been made to estimate biomass and NPP based on equation form of $Wt=aD^bH^c$ for Quercus variabilis and Quercus mongolica natural stands(Mean age; 67, 62yrs old) in Chungju. Equation form of $Wt=aD^bH^c$ was more adequate than $Wt=a(D^2H)^b$ and $Wt=aD^b$ for the estimation of the biomass and NPP. Individual biomass was compared using a paired t-test by tree component which showed no significant differences. Total aboveground biomass of Quercus mongolica was 130.6 t/ha and that of Quercus variabilis was 137.4 t/ha. Biomass of Q. mongolica was composed of foliage 5.1 t/ha(3.9%), dead branch 3.5 t/ha(2.7%), live branch 29.7 t/ha(23.0%), bolebark 16.2 t/ha(12.5%), and bolewood 74.9 t/ha(58.0%), and that of Q. variabilis was composed of foliage 3.8 t/ha(2.9%), dead branch 2.9 t/ha(2.2%), live branch 24.3 t/ha(18.4%), bolebark 20.4 t/ha(15.5%), and bolewood 80.4 t/ha(61.0%). Net primary production was 10.0 t/ha/yr in the Q. mongolica stand and 8.6 t/ha/yr in the Q. variabilis stand, respectively. Net primary production of Quercus forest in Chungju was very close to the mean NPP of the broadleaved forest of temperate zone.

• Journal of Korean Society of Forest Science
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• v.102 no.4
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• pp.543-549
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• 2013

This study was conducted to evaluate age-specific and generalized allometric equations and biomass expansion factors (BEFs) for each tree component across three age-sequence stands (35-year-old, 51-year-old, 62-year-old) of black pine (Pinus thunbergii Parl.) in Jinju, located in the western part of Gyeongnam province, Korea. Biomass in each tree component, i.e. foliage, branch, and stem, was quantified by destructive tree harvesting. Allometric regression equations were significant (P<0.05) with diameter at breast height (DBH) or combination of DBH and height ($DBH^2H$) accounting for 55-98% of the variation (as indicated by coefficients of determination, $R^2$) in aboveground biomass except for foliage biomass of the 62-year-old stand. Generalized allometric equations can be used to estimate the biomass of black pine stands because the slopes of age-specific equations over 35-year-old stands were not significantly different by the age-sequence. The stem density and biomass expansion factor (BEFs) were not significantly different (P>0.05) from different stand ages and ranged from 0.45 to $0.51gcm^{-3}$, and from 1.32 to 1.38, respectively. The results indicate that allometric equations, stem density and aboveground BEFs in the matured black pine over 35-year-old are little influenced by different stand ages.

• Journal of Life Science
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• v.21 no.8
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• pp.1183-1189
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• 2011

The present study is aimed at examining the effects of the physico-chemical environmental factors of water systems on water bloom at Homin and Gagok reservoirs in Pungcheon-Myeon, Andong, Gyeongsangbuk-do. The mean water temperature and the contents of chlorophyll-a, total-nitrogen, total-phosphorus and phosphate-phosphorus were higher at the Gagok reservoir. On the other hand, the pH mean value was higher at the Homin reservoir. The mean value of microelements (Na, K, Mg, Fe, Si) was higher at the Gagok reservoir. The cyanobacteria which was considered to be the cause of water bloom at the two reservoirs was Microcystis aeruginosa. It started to grow in May and showed the highest standing crop in August. Between the increase of standing crop of M. aeruginosa and the water quality, correlation values of $Na^+$ (r=-0.910, p<0.05), $Fe^{2+}$ (r=-0.855, p<0.05) and $Si^{4+}$ (r=0.989, p<0.01) at the Homin reservoir increased amount of standing crop. Meanwhile, at the Gagok reservoir, the contents of $Na^+$ (r=-0.776, p<0.05), $Si^{4+}$ (r=0.899, p<0.05) were highly related to the increase of standing crop. Interestingly, Si, which is the limiting factor for diatoms, has a high correlation with standing crop of cyanobacteria. In conclusion, the water blooming is caused not by a simple factor but a synergistic effect due to complex actions including high concentrations of nitrogen and phosphorus ions and many other environmental factors.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.242-245
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• 2004

This study was conducted to assess water quality of Dae stream in Busan using the periphyton. Species of the higher rank 10% in standing crops were Cymbella ventricosa, Aulacoseira granulata, Gomphonema olivaceum, Synedra ulna through the study. In addition, Fragilaria intermedia ill the station 1 and 2, and Nitzschia palea in the station 3 and 4 dominated the periphyton community respectively. These species mainly appeared in the urban stream. Where input of pollutant is forecasted, standing crops of dominant species are investigated very highly. Also, standing crops of Nitzschia palea were higher in the pollution area such as polysaprobic than any other area. Water quality by the saprobic index were oligosaprobic in the station 1, $\beta$-mesosaprobic in the station 2 and 3, and $\alpha$- mesosaprobic in the station 4. These results suggests that the pollution of Dae stream gradually increased with downstream due perhaps to the loading of sewage from the new residental complex.