• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.1
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• pp.70-79
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• 2000

Arbuscular mycorrhizal(AM) fungi have significant role for ecosystem structure and function. They are the major component of forest soil ecosystems and critically important for water and nutrient cycling in the system. To understand the ecology of AM fungi the fungal spores were collected, identified and counted in forest soils under various climatic and edaphic conditions. In relation to soil depth 90% of AM fungi spores and mycorrhizas distributed within 15cm soil depth. Number of spores per $100m{\ell}$ forest soil volume was 5 to 36 spores from 1 to 3 fungal species. AM fungal species diversity was higher in warmer climates, and more moist and fertile soils. The most frequently found species were Gigaspora decipiens irrespective of soil moisture and Gi. gigantea irrespective of soil fertility. In the Jeju island the soils of Cryptomeria japonica plantations and Miscanthus sinensis var. purpurascens meadow had more AM spores than the other soils. We suggest AM fungi be considered as keystones species when restoring a disturbed forest ecosystem.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.3
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• pp.108-128
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• 2002

In order to investigate the ecological characteristics of phytoplankton communities around a nuclear power plant in Gori coastal waters of the South East Sea, Wolseong and Uljin coastal waters of the East Sea and Younggwang coastal waters of the Yellow Sea, the standing crops and chlorophyll-$\alpha$ concentrations of phytoplankton were studied during 1992~1996 and the relationships between standing crops and environmental variables were analyzed. The concentrations of nitrogenous nutrients were on average 0.101, 0.094, 0.072 and 0.108mg/$\ell$ and those of phosphorus were on average 0.007, 0.008, 0.006 and 0.009mg/$\ell$ in Gori, Wolseong, Uljin and Younggwang, respectively. The N:P ratios were highly variable, ranging from 3.2 to 57.3, from 3.1 to 109.0, from 2.6 to 102.0 and from 1.0 to 165.0 in Gori, Wolseong, Uljin and Younggwang, respectively. The concentrations of suspended solids were on average 18.7, 16.7, 11.6 and 52.7mg/$\ell$ and transparencies were on average 3.8, 5.4, 7.9 and 0.7 m in Gori, Wolseong, Uljin and Younggwang, respectively. Total standing crops of phytoplankton averaged 710,659, 687,508, 656,245 and 1,278,173cells/$\ell$ in Gori, Wolseong, Uljin and Yaunggwang, respectively. The standing crops of microplankton(>20${\mu}{\textrm}{m}$) averaged 357,546, 333,638, 276,407 and 592,975cells/$\ell$ those of nanoplankton(<20${\mu}{\textrm}{m}$) averaged 353,113, 353,870, 379,838 and 574,563cells/$\ell$ in Gori, Wolseong, Uljin and Younggwang, respectively. While standing crops of diatoms were averaged 282,009, 284,710, 238,758 and 574,563 cells/$\ell$, those of dinoflagellates were averaged 46,079, 35,401, 32,906 and 16,749 cells/$\ell$ in Gori, Wolseong, Uljin and Younggwang, respectively. The seasonal standing crops of diatoms in Gori, Wolseong and Uljin were higher in Spring than other seasons, but were lower in Summer than other seasons in Younggwang. The seasonal standing crops of dinoflagellates in Gori and Younggwang were higher in Summer than other seasons, but were higher in Autumn than other seasons in U]jin. Average of chlorophyll-$\alpha$ concentrations ranged from 2.16 to 4.28$\mu\textrm{g}$/$\ell$ in 4 study areas with the highest concentration occurred in Younggwang. Indices of species diversity ranged from 2.11 to 2.24 in 4 study areas. While community structures of phytoplankton were unstable during winter and stable during summer in Gori, Wolseong and Uljln coastal waters, those of phytoplankton were stable during winter and summer than during spring and autumn in Yaunggwang. The analysis results of Pearson product moment correlation coefficient between standing crops and environmental variables showed that distributions of standing crops were affected by transparencies, suspended solids, and some nutrient(N $O_3$$^{[-10]}$ -N, P $O_4$$^{3-}$-P), even though the degree of influences were a little different according to the season and the surveyed zone.

• Korean Journal of Microbiology
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• v.28 no.3
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• pp.204-209
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• 1990

The total and heterotrophic bacterial distributions, compositions and alkaline phosphatese actibities were analyzed in Lake Soyang from Sep. 1987 to Aug. 1988. The heterotrophic bacteria was small portion, 0.07-2.63% of total bacterial number which ranged from $3.2{\times}10^{5}$ to $3.2{\times}10^{6}$ cells/${\mu}\ell$. The composition of bacterial community was less diverse in summer and at the fish farm site and Peridinium blooming site. Pseudomonas and Flavo bacterium were the dominant genera in all sites. The highest proportion and activity of alkaline phsophatase was appeared in Flavobacterium, while Pseudomonas was the most predominant group.

• Journal of Environmental Science International
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• v.11 no.3
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• pp.149-154
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• 2002

This study was conducted to find the structure of phytoplankton community in the Hoeya river(Ulsan) from March 2000 to February 2001. The taxa of phytoplankton identified included 135 species, 5 divisions, 33 families and 82 genera. Among them, chrysophyta(diatoms) were 63 species(46.7%), chlorophyta(green algae) 47 species(34.8%), pyrrophyta(dinoflagellates) 13 species(9.6%), cyanophyta (cyanobacteria) 8 species(5.9%) and euglenophyta(euglenoids) 4 species(3.0%) respectively. Ecological important species is called frequently appearing species, red tide causative species, seawater species and pollution indicator. 22 species including Aulacoseira granulate were recorded frequently appearing species. 19 species including Ceratium furca were recorded as red tide causing species. And the pollution indicators were 33 species including Actinastrum hantzschii var. fluviatile. The highest standing crops were 3,103,441 cells/$\ell$ in August at the RW-1 and the lowest 1,245 cells/ $\ell$ in January at the RW-5. In the community analysis, the dominanance indices ranged from 0.34(October, RW-2) to 0.94(January, RW-1) and the diversity indices from 0.50(May, RW-2) to 2.57(September, RW-2). The saprobic indices were 2.43 in RW-1, 2.41 in RW-2, 2.375 in RW-3, 2.40 in RW-4, 2.43, in RW-5. Therefore, these areas were investigated "$\beta$-mesosaprobic". According to the similarity index among the stations, these areas were defined as residential district areas(RW-2 and RW-3), lower part of the dam (RW-1) and seawater areas(RW-4 and RW-5).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.4
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• pp.511-517
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• 1999

Determining the simultaneous flow rate in any particular section of piping is the important step in order to determine the size of water supply piping. Now we are using the diversity curve of common water closet in order to determine the simultaneous flow rate of water supply piping, but there is a difference between a determined flow rate of general water closet and that of water closet for water saving. This study aims to find out the fixture unit of a flush valve type water closet for water saving in office building, and to determine the correlation between the fixture units and peak flow rates on the basis of the probability theory. A flush valve type water closet for water saving that have a 7.5 second duration of flush operation with an average design flow rate 72 $\ell$/fin was considered. Simulation results indicate that the number 5 is shown to be reasonable to the fixture unit of water closet for water saving. And the design can be undersized considerably with the revised diversity curves using modified fixture unit.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.3
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• pp.41-51
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• 2012

Biohydrogen production and analysis of microbial community were attempted from the sugar manufacturing wastewater with anaerobic fermentation process. Addtion of nutrients ($N{\cdot}P$) into sugar manufacturing wastewater stimulates hydrogen production from 9.53 to $26.67m{\ell}$ $H_2/g$ COD. Butyric acid, acetic acid, lactic acid, and propionic acid were detected in the sample of the anaerobic fermentation process. Butyric acid/Acetic acid(B/A) ratio was increased 0.50 to 0.92 according to the nutrients addtion into the wastewater. Microbial community was analyzed as Clostridium sp. in the phylum of Firmicutes and Klebsiella sp., Erwinia sp., and enterobacter sp. of the class of $\gamma$-Proteobacteria. As the improvement of hydrogen production, Erwinia sp. was decreased and Klebsiella sp. was increased.

• Journal of Environmental Science International
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• v.20 no.2
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• pp.261-274
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• 2011

The studies on community structure of benthic macroinvertebrates and environmental survey in selected four sites were performed on wetland Upo from 2008 to 2009. The lowest water temperature was measured at Upo and Mokpo showing $7^{\circ}C$ in February of 2008 and 2009 respectively. The highest water temperature was measured at Upo showing $32^{\circ}C$ in August of 2009. The lowest pH was measured at Topyeong with 5.3 in August of 2009, and the highest pH was measured at Mokpo with 10.1 in August of 2008. Generally the levels pH of 2008 were higher than those of 2009. The range of electric conductivity to the sites was big. Overall, the higher electric conductivity was seen at Sajipo and the lower one was seen at Mokpo. The level of Dissolved oxygen was lowest at Upo with $5.53mg/\ell$ in August 2008, and it was highest at Upo with $14.76mg/\ell$ in February of 2008. The investigation was performed with both quantitative and qualitative collecting methods from four surveying sites, Upo, Mokpo, Sajipo and Topyeong. Through the eight times of seasonal survey, 6 classes, 17 orders, 59 families, 131 species and 5460 individuals of benthic macroinvertebrates were collected. 6 classes, 17 orders, 53 families 106 species and 2439 individuals were identified in 2008, and 6 classes, 16 orders, 44 families, 93 species and 3021 individuals were collected in 2009. The number of species was decreased in 2009 comparing that of 2008, however, the number of individuals were increased in 2009. The dominant species and the subdominant species was Plea (Paraplea) indistinguenda and Diplonychus esakii with 20.16% and 11.90% of dominant indices respectively. From the community analysis, both the species diversity index and the species richness index were highest in Topyeong showing 4.743 and 9.054 respectively. The similarity evaluation to the investigation sites with the species in there showed very high similarity among Upo, Mokpo and Sajipo showing 5 or lower levels of distance cluster combine.

• Korean Journal of Environmental Biology
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• v.20 no.1
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• pp.85-90
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• 2002

In an artificial pH-gradient batch culture system, the author analyzed the effects of acidification on the species composition of heterotrophic bacteria. As the result of this study, it was found that the numbers of total bacteria were not affected by acidification and that the population size of heterotrophic bacteria decreased as pH became lower. The heterotrophic bacteria isolated from all of the pH gradient were 12 genera and 22 species, and among them, gram negative and gram positive bacteria were 04% and 30%, respectively. As pH decreased, the distribution rate of gram negative bacteria increased while that of gram positive bacteria decreased. Regarding to distribution rate of genuses in each pH gradient, 13 genuses appeared at pH 7 while only 5 genuses appeared at pH 3, which means that the diversity of genera decrease as pH decreased. The activities of extracellular enzyme showed the ranges of $0.008-0.292\;\mu{M}\ell^{-1}\;hr^{-1}$ in bioreactor system. The enzymatic activities decreased rapidly below pH 5 and then sustained 5-38% at the lower pH values.