• Korean Journal of Ecology and Environment
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• v.48 no.1
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• pp.38-50
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• 2015

Appearance patterns of freshwater fish were investigated in the western Demilitarized Zone (DMZ) adjacent areas near Imjin River in Gyeonggi-do, Korea, of 2014. A total of 61 species belonging to 14 families were found in the river during the survey. The dominant and subdominant species were Zacco platypus (Relative abundance, 20.3%) and Zacco koreanus (12.6%), respectively. Other abundant species include Rhinogobius brunneus (9.2%), Pungtungia herzi (4.4%), Acheilognathus yamatsutae (4.4%), and Pseudogobio esocinus (4.0%). Among the residing species, 24 species (39.3%) were endemic to Korea; and 1 species, Carassius cuvieri, was non-indigenous species. Hemibarbus mylodon is a natural monument, and Lethenteron reissneri, Acheilognathus signifer, Pseudopungtungia tenuicorpa, Gobiobotia brevibarba, G. macrocephala, and G. naktongensis are endangered species in Korea. In addition, Anguilla japonica and Plecoglossus altivelis are catadromous and amphidromous species, respectively. Among the investigated sites, the lower part of Sami Stream (St. 5, 6) and Gunnarm-dam region (St. 11, 14) are particularly valuable for the conservation of species diversity, because many fish species (33~42 species) including a natural monument and several endangered species inhabit in these regions.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.3
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• pp.253-262
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• 1990

Hardened seed oysters which inhabit the Hansan Bay of Korea and Hiroshima Bay of Japan were cultured at the oyster farm of Nino island near Hiroshima from June, 1972. to June, 1973. The present experiment investigated monthly increment of shell height, shell length, meat weight, moisture, fatness and gonad development of the seed oysters. Environmental factors were also checked to know ecology of the oysters. The oyster farm of Nino island near Hiroshima city showed high water temperautre and low salinity com-paring with the oyster farm of Hansan Bay. Korea. Shell height and shell ten求h of the hardened seed oyster of Hansan Bay grew faster than those of Hiroshima Bay, especially in oyster meat weight. Histological observation on gonads showed little difference in developmental process between the two localities from June through December, 1972, whereas the hardened seed oyster from Hansan Bay has grown rapidly in the development of gonad after February, 1973. It can be concluded that in the viewpoint of seed oysters productivity the hardened seed oyster from Hansan Bay is more effective than that of Hiroshima Bay comparing in seed growth, fatness and developmental process of gonad.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.248-254
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• 2010

To define the optimum conditions for the mass production of four antifungal Pseudomonas spp. isolated from soil, we have investigated culture conditions and effects of various nutrient sources on the bacterial growth and evaluated antagonistic activity against Rhizoctonia solani and Sclerotinia homoeocarpa, plant pathogens. The optimum temperature and pH for the growth of these isolates were determined as pH 7.0 and $20^{\circ}$ or $25^{\circ}C$, respectively. Sucrose, tryptone, and $K_2HPO_4$ generally were more adequate for better growth as carbon, nitrogen and mineral source, respectively. The nutrient sources were also found to be very effective for high antifungal activities against R. solani and S. homoeocarpa. It was elucidated that YUD-F group (P. mandelii and P. fluorescens), which inhabit regions at relatively low temperature, had more broad spectrum and higher antifungal activity than YUD-O group (P. trivialis and P. jessenii) generally against R. solani and S. homoeocarpa. It is thought that the differences of the average temperature in the various habitats of Pseudomonas spp. influence the optimal growth temperature and antifungal activity. Especially, Pseudomonas spp. of YUD-O group showed the better antifungal activity against dollar spot caused by S. homoeocarpa, but showed relatively weaker antifungal activity against brown patch caused by R. solani.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.179-183
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• 2001

Shortnecked clam, Ruditapes philippinarum, is one of the very important shellfish produced in south-western coast of Korea. But it's ready to be polluted and have sand in flesh because it mainly inhabit in silt at the inside of coastal area. This study was carried out to obtain informations about the elimination of sand in shortnecked clam harvested from western coast of Korea. During rearing shortnecked clams in water tank, the elimination rates of sand from them at 6, 13, 23, $28^{\circ}C$ were 59.0, 88.2, 97.9, $96.1^{\circ}C$ after 48 hours, respectively. The sand was eliminated above $95^{\circ}C$ from the shellfish at 32,9 to $40\%_{\circ}$ of salinity after 48 hours. But the sand elimination from them was incomplete and inconsistent at 10 to 20 of salinity. The sand was eliminated rapidly at pH 1.9 to 9.0 however, its elimination was not effective at neutral or acidity range, It was found that the sand elimination was most effective at $23^{\circ}C, 35\%_{\circ}$ salinty and pH 9.0. Reasonable flow rate for sand eliminate in shortnecked clam was above 150 L/min./shellfish $m^3$ under both 3,000 and 4,000 L/shellfish $m^3$, and above 100 L/min,/shellfish $m^3$ under both 6,000 and 8,000 L/shellfish $m^3$ in water tank.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.184-189
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• 2001

Surf clam, Mactra veneriformis, is a important shellfish produced in south-western coast of Korea. But it's ready to be contaminated and have sand in flesh because it mainly inhabit in silt at tHe inside of coastal area. We determined optimum conditions for the sand elimination and microbial depuration in the shellfish harvested from western coast of Korea. It was found that the most effective conditions of process water for the sand elimination were $23^{\circ}C$, $32.9-35.0\%_{\circ}$ salinity and pH $7.9\~9.0.\;A$ surf clam contained about 210 mg of sand whose $94\%$ was eliminated after 24 hours in natural sea water ($32.9\%_{\circ}$ , pH 7.9) controlled at $23^{\circ}C$. To eliminate both sand and microorganisms contaminated in surf clam, the process water should be run during at least 36 hours for the former and 24 hours for the latter at 150 L/minute/$m^3$of shellfish, when its volume was above 4,000 L/$m^3$ of shellfish in 2 tons of tank.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.57-62
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• 1985

The three tide pools of Kanagawagen Aburatsubo coast, Japan were studied for 5 months (June-October, 1991) to know the physicochemical factors and changes of the microflora, In the tide pools salinity was ${\simeq}35\%0$, temperature range was $14{\sim}32^{\circ}C$ and pH range was $7.4{\sim}8.9$. Particulate organic carbon (POC) was $255{\sim}3980\;{\mu}g-at/l$, and total phosphate-P was $1.0{\sim}27.0\;{\mu}g-at/l$. The numbers of suspended bacteria and heterotrophic bacteria on the algae were $10^4{\sim}10^7/ml$ and $10^6{\sim}10^8/g$, respectively. Bacterial flora isolated from the Samples were Acinetobacter spp., Moraxella spp., Flavobacterium spp. and Pseudomonas spp., While Acinetobacter spp. was predominant among them. T. japonicus occurred dominantly with densities of $2200{\sim}7000/l$ during $August{\sim}september$. During this period the sharp increases of the unicellular microalgae and the protozoans were observed. According to the experimental results (POC, total phosphate-P, numbers and composition of bacterial flora), T. japonicus seemed to inhabit the environment with high eutrophication and high variability.

• Korean Journal of Ichthyology
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• v.27 no.4
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• pp.275-283
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• 2015

Habitat characteristics and feeding ecology of Iksookimia pacifica were investigated in this study to provide baseline data for its ecological characteristics in Bukcheon (stream), Goseong-gun, Gangwon-do, Korea. The main inhabit of I. pacifica was found to be sand bottoms of Bb or Bc river type with slow water flow. Based on studies of their habitat preferences according to age, their preference for sand bed was the same. However, their preference for depth and velocity was different. When their age was increased, their depth preference was also increased ($24.9{\pm}17.61cm$ for 0+ year, $69.6{\pm}30.32cm$ for 1+ year, $82.4{\pm}33.30cm$ for 2+ years, and $90.0{\pm}31.55cm$ for $3+{\leq}$ years). The water velocity was found to be 3.8 ~ 4.0 cm/sec for ages between 0+ and 1+ and 6.0 ~ 7.3 cm/sec for ages between 2+ and $3+{\leq}$. They were active on sand from March to November. They would hibernate in sand during the winter season. During the day from 12 pm to 24 am, they were highly active with high food consumption. Their main food sources analyzed with index of relative importance (IRI) include Chironomidae (76.7%), Simuliidae (10.3%), Rotatoria (7.3%), and Arcellidae (2.2%). Their juveniles (total length 20~40 mm) would feed on small-sized preys such as Rotatoria, Copepoda, and Arcellidae. Older I. pacifica would feed on big-sized preys such as Chironomidae and Simuliidae.

• Korean Journal of Environment and Ecology
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• v.29 no.1
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• pp.14-20
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• 2015

We created species richness maps of mammals, birds and plants using "Nnational Ecosystem Survey" data and identified correlations between species richness maps of each taxa. We examine the distribution of species richness of each taxa and calculated conservation priority rank through plotting species-area curves using an additive benefit function in Zonation. The conclusions of this study are as follows. First, plant showed high species richness in Gangwon province and Baekdudaegan, and mammals showed high species richness at eastern slope of Baekdudaegan in Gangwon province unusually and the species richness of mammals distributed equally except Gyeonggi and Chungnam province. However, birds showed high species richness in the west costal because the area is the major route of winter migratory birds. Second, correlation of each taxa's distribution is not significant. Correlation between mammals and birds is positive but correlations between birds and others are negative. Because mammals inhabit in forest but birds mostly live in coastal wetlands and rivers. Therefore, bird's habitats are not shared with other habitats. Third, the probability of mammals occurrence is very low under 25% in species-area curve, others increase proportionally to area. Birds increase dramatically richness at 10% because bird's habitat is concentrated in coastal wetlands and rivers. Plants increased gently species richness due to large forest in Gangwon province. We can calculate the predicted number of species in curves and plan various conservation strategies using the marginal number of species. Finally, high priority ranks for conservation distributed mainly in Gangwon province and Baekdudaegan. When we compared with priority map and terrestrial national parks, the parks were evaluated as high priority ranks. However, the rank of parks away from Baekdudaegan was low. This study has the meaning of selecting conservation priority area using National Ecosystem Survey. In spite of the omission of survey data in national parks and Baekdudaegan, the results were good. Therefore, the priority rank method using species distribution models is useful to selecting protected areas and improving conservation plans. However, it is needed to select protected areas considering various evaluation factors, such as rarity, connectivity, representativeness, focal species and so on because there is a limit to select protected area only using species richness.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.667-677
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• 2013

The introduction of a new transit facility affects mode share of travel alternatives. The multinomial logit model, which has been the most commonly used for estimating mode share, has difficulty in reflecting heterogeneity of travelers' choices, and it has a limitation on grasping their characteristics of mode choice. The limitation may lead to over- or under-estimation of the new transit facility and bring about significant social costs. This paper aims to find a methodology to overcome the problem of preference homogeneity. It also applies market segmentation structure of separating the whole population into direct and indirect beneficiary to consider their preference heterogeneity. A mode choice model is estimated on data from Jeju Province and statistically tested. The results show that mode transfer rate of direct beneficiaries that inhabit in downtown areas increases as the new transit facility provides more advanced services with higher costs. The results and the model suggested in this study can contribute to improving the accuracy of demand forecasting of new transit facilities by reflecting heterogeneity of mode-transfer patterns.

• Journal of Life Science
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• v.27 no.9
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• pp.1086-1095
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• 2017

There is growing interest in groundwater resources to overcome the loss of surface water resources due to climate change. An understanding of the microbial community of aquifers is essential for monitoring and evaluating groundwater contamination, as well as groundwater management. Most microorganisms that inhabit aquifer ecosystems are attached to sediment particles rather than planktonic, as is the case in groundwater. Since sampling aquifer sediment is not easy, groundwater, which contains planktonic microorganisms, is generally sampled in microbial community research. Although many studies have investigated microbial communities in contaminated aquifers, there are only a few reports of microbial communities in uncontaminated or pristine aquifers, resulting in limited information on aquifer microbial diversity. Such information is needed for groundwater quality improvement. This paper describes the ecology and community structure of groundwater bacteria in uncontaminated aquifers. The diversity and structures of microbial communities in these aquifers were affected by the concentration or distribution of substrates (e.g., minerals, organic matter, etc), in addition to groundwater characteristics and human activities. Most of the microbial communities in these uncontaminated aquifers were dominated by Proteobacteria. Studies of microbial communities in uncontaminated aquifers are important to better understand the biogeochemical processes associated with groundwater quality improvement. In addition, information on the microbial communities of aquifers can be used as a basis to monitor changes in community structure due to contamination.