• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.4
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• pp.373-379
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• 1994

Final biomass yields(cells/ml) and growth rates(divisions/day) of 4 clones of marine diatoms isolated from the Korean coastal waters were measured in media with 6 different levels of added cadmium concentrations. A neritic diatom, GS-12(Chaetoceros sp.), showed no growth at 0.1ppm cadmium, and its $IC_{50}$ for final biomass yield and growth rate was 0.03 and 0.02ppm, respectively. Two clones isolated from tidal pool, NC-37 and NC-29, showed enhanced tolerance to cadmium toxicity. Extremely high tolerance to cadmium addition was found in J-21 from a eutrophicated bay, with its high $IC_{50}$ for biomass yield(1.07ppm) and growth rate(1.92ppm). Present results implied a habitat related pattern of coastal diatom clones in the cadmium tolerances. Except GS-12, the other three diatom clones are considered to be highly tolerant to cadmium stresses.

• Journal of Plant Biology
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• v.11 no.2
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• pp.1-30
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• 1968

The Han River was investigated monthly from April through September, 1967 at Chun-chon reservoir, Shin-yean, So-yang, Chung-pyong reservoir, Yang-soo-ri and Gi-doo-won to clarify the phytoplankton and to study its seasonal variation. At the same time, vertical distribution of phytoplankton was also studied from June through September at Chun-chon and Chung-pyong reservoir. The results obtained are as follows: As the environmental conditions, water temperature, dissolved oxygen, pH, and transparency were determined. The plankton samples collected from six stations were identified and classified by Engler's classification system. It resulted in 4 phyla, 4 classes, 3 subclasses, 13 orders, 27 families, 5 tribes, 71 genera, 222 species, 1 subspecies, 51 varieties and 2 forms. The total number of phytoplankton identified was 276. Of them, 84 species, 1 subspecies 26 varieties, 2 forms were recorded in this paper for the first time. Considering with the habitat of the total number of phytoplanktons, the highest percentage of Limnoplankton existed in the Chung-pyong reservoir. It suggests that hte Chung-pyong reservoir is becoming to have the character of lake. The planktons appeared commonly during six months at six station belong to Chrysophyta including 22 species in 11 genera. Among these 22 species, Navicula, consists of 6 species, was the most abundant. The number of species identified uniquely at each station were 5 species in the Chun-chon reservoir, 6 in Chung-pyong and Yang-soo-ri, 8 at Shin-yean, 11 at So-yang, and 18 at Gi-doo-won. The number of species occurred at all stations were 29 in spring, 42 in Autumn and during investigation period. The maximum production of total phytoplankton was generally shown in the late spring and the early fall with differences in quantity at six collecting statins. In the Chun-chon reservoir, the high concentration of approximately 1, 190, 000 cells per litter in the months of August and September was due to the increase of Chrysophyte genus, Melosira and the highest concentration of approximately 2, 000, 000 in July at Gi-doo-won was caused Chlorophyte genus, Secenedesmus. The Chun-chon reservoir of three years old was different from the Chung-pyong reservoir of 25 years old with respect to increase in Melosira genus in August and September. After the completion of the Ui-am reservoir, though there was an increase in total density, the number of species of phytoplankton was not changed. It suggests that Ui-am reservoir is similar to the Chun-chon reservoir under the influence of the latter. The density of total phytoplankton was generally high at the depth of 2m to 5m for the two reservoirs.

• Korean Journal of Environment and Ecology
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• v.33 no.6
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• pp.645-653
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• 2019

The purpose of this study was to understand the factors that affected activities and differences in seasonal activities of the invasive red-eared slider turtle (Trachemys scripta elegans) at Ansan reed wetland in Sangnok-gu, Ansan, Gyeonggi Province, the Republic of Korea. We installed nine nets in the study region to capture turtles and checked the nets twice a day for 154 days from April 28 to September 28 2013. In total, 60 individuals, including 12 juveniles, 26 adult males, and 22 adult females, were captured in 96 of 308 net checks. The multiple regression analysis of 12 environmental factors was conducted to analyze activity factors of red-eared slider turtle by assuming the number of turtles captured for a week to be the indicator of the activeness of the turtles. The result showed that the daylength was the only environmental factor that significantly affected the turtles' activity (p<0.001), and none of the other factors showed a significant correlation. The highest activity was recorded at the end of May, which was the beginning of the reproductive period. The daylength during the breeding season was significantly different from that during other seasons (Kruskal-Wallis test, p<0.001). The information about the relationship between environmental factors and species in habitat can be useful for the management of invasive alien species in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.410-418
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• 2000

In general, the experienced diver go into the water to find out Pan Shell which is spontaneously generated and brought up at the depth of 25-30 meters in the slime along the bank of an inlet of western and southern sea. However, this searching system has caused some problems in terms of economical efficiency and riskiness of diver. To overcome such problems and enhance the competence capability of fishermen, a new Pan Shell searching system is required. If an onboard searching system as a substitute of the way of diving into the deep water to identify the existence of Pan Shell is developed, it would be greatly beneficial to fishermen. The purpose of this research is to develop a new searching system of Pan Shell by making use of 50-200 Khz Ultra Sonic Signal, A/D Converter and computer process program. Based on the fact that Sonic Signal between the soft part of slime and the hard part of sand, pebble and Pan Shell is different, the possibility of this system have been approved in some degree by this time of research. However, to utilize this new system, further research on the establishment of data base and sample data is required. With the theoretical knowledge, the systematic research on the searching capability of Ultra Sonic Signal will be continued to identify the influence against the sea water subject. In this research, signal will be analyzed according to the influence range, power and sensitiveness of Ultra Sonic Generator. In addition, the radius of Ultra Sonic Signal will be included. The experimental field work will be executed at Nockdong, Pulkyo and other places well known as a habitat of Pan Shell.

• Journal of the Korean Geographical Society
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• v.49 no.3
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• pp.321-338
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• 2014

This study aims to identify spatial distribution of estuarine wetlands in Korea, and to assess temporal variation of the wetlands in the last few decades. Widely known in environmental and coastal management, watershed-based regions which composed with Han-river(western and eastern parts), Keum-river, Yeoungsan-river, Seomjin-river, Nakdong-river, and Jeju, are analyzed to evaluate temporal change of estuarine wetlands in the 1980s, 1990s, and 2000s, through the land-cover map. Results show that estuarine wetlands dramatically decreased in Han-river(western part), Keum-river, Yeoungsan-river that estuarine circulation have been interrupted with man-made structures such as dyke and drainage. But, estuarine wetlands surrounded by forests and grasslands has been relatively less damaged. Habitat diversity providing healthy estuary ecosystem is lower in interrupted estuaries than circulated estuaries, which are composed of tidal-flat, open water, salt marsh, rocky coasts and sandy shoreline. This study indicates that spatial distribution and temporal variation of estuarine wetlands are different with estuary type and region, so estuary type with seven regions can be applied to provides a framework for estuary management strategies and to establish estuary restoration plans.

• ALGAE
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• v.30 no.1
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• pp.59-66
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• 2015

The growth and hole formation of Ulva australis were examined at seven coastal areas of Korea between July and August, 2013. Animal species and weight growing on the Ulva fronds were estimated at Haseom, Pohang, and Woedo. The effects of wave exposure on the morphological features and residential animals of Ulva fronds were investigated at wave-exposed and sheltered sites of Seongsan on October 19, 2013. U. australis had different frond areas ($82-665cm^2$), hole areas ($2.5-6.3cm^2$), and hole numbers (9.8-41.3 holes) at the seven sites. Within $0.1m^2$ of Ulva frond, hole areas ranged from 0.37 to $5.94cm^2$, and between 4.9 and 36.2 holes were observed. Fourteen residential animal species were observed at the three evaluated sites, 75.0 (Haseom) to 408.7 individuals $100g^{-1}$ Ulva (Pohang) per site. The dominant residential species at each site differed with Amphithoe sp. at Haseom, Monodonta spp. at Pohang, and Pagurus sp. at Woedo. The growth (frond area, wet weight) and hole number of Ulva fronds, and the number of residential animals were significantly greater in samples collected from the sheltered shore than the wave-exposed shore of Seongsan. The present results showed U. australis grew well at sheltered shores and had more holes on the fronds due to abundance of residential animals. The dominant residential animals (crabs, gammaridea, and snails) were similar in the Ulva populations of sheltered and wave-exposed shores, but greater species diversity was observed at the exposed shore (18 species ver. 11 species). In conclusion, U. australis is a keystone species providing habitat to various invertebrates and frond holes are positively correlated to the number of residential animals.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.3
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• pp.149-159
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• 2012

To elucidate the species compositions of estuarine and inshore fauna and compare productivities between them, catch were collected by bag nets in the Han River estuary off Ganghwa Island and the inshore waters off Jangbong Island for 24 hours at the spring tide from March to December 2010. Community structures of nekton assemblages were different with area, month, taxonomic groups. Although the diversity of estuarine nekton assemblage was lower than that of inshore nekton assemblage, the productivity of nekton assemblage in estuary was higher than that in the inshore waters. Nekton assemblages were distributed according to habitat environment: the estuarine species, Coilia mystus, Chelon haematocheilus, Collichthys lucidus were prominent in the Han River estuary off Ganghwa Island, and marine species, Thryssa kammalensis, Sardinella zunasi, Portunus trituberculatus were prominent in the inshore waters off Jangbong Island. Palaemon gravieri, Exopalaemon carinicauda, Synechogobius hasta were inhabited in both waters. The health assessment of estuarine ecosystem based on scientific research will be contributed to the effective management of estuary with determination of order and direction in policy.

• Korean Journal of Environment and Ecology
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• v.12 no.3
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• pp.236-241
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• 1998

This study was to compare soil characteristics among Quercus mongolica communities that characterize the boreal-temperate deciduous forest in Korea. The classification of Quercus mongolica community and soil sampling were carried in Mt. Odae and Mt. Jungwang in Kangwondo from April of 1991 to October of 1994. The study area was classified as 5 Quercus mongolica communities with Braun-Blanquet method as follows; Quercus mongolica - Abies nephrolepis, Quercus mongolica - Acer pseudosieboldianum, Quercus mongolica - Lindera obtusiloba, Quercus mongolica - Acer mandshuricum, and Quercus mongolica - Carpinus cordata communities. Quercus mongolica - Abies nephorolepis community had the most shallow depth of A horizon(5cm) among communities, and root penetration was mainly from 0 to 10cm soil depth, and they had a dry soil moisture condition. Depth of A horizon of Quercus mongolica - Lindera obtusiloba and Quercus mongolica - Acer mandshuricum communities was about 20cm, and root penetration was mainly from 0 to 20cm soil depth, and they had a slightly dry soil moisture condition. Quercus mongolica - Acer mandshuricum, and Quercus mongolica -Carpinus cordata communities had the deepest depth of A horizon(35cm) and root was well developed over 45cm, and they had a moderately-slight dry soil condition. The soil organic matter, total N, exchangeable Ca, Mg and K concentration and CEC was the greatest in Quercus mongolica-Acer mandshuricum community and Quercus mongolica-Carpinus cordata community among communities. Quercus mongolica - Abies nephyolepis community had the smallest soil organic matter, total N, and CEC among communities. There were large differences among Quercus mongolica communities by soil properties and the result may be due to different habitat positions in the landscape among communities.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.354-371
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• 1993

Behavior of adult females of the smoky brown cockroach was observed for 10-15 days continuously by using computer and the automatic sensoring system. Under the light condition of l2L~ 12D, individual variations were generally higher and the periodicity appeared less in terms of the presence time at the micro-habitats and the locomotory activity. The smoky brown cockroach appeared 20.42, 11.50, 6.31 and 2.66 % in a day in averages respectively at the shelter and the places for other individuals, feeding and drinking. It stayed 20.29 % in a day at the shelter when food, water, and other individuals were not supplied. Visiting rates were higher at the feeding and dnnking places than at. the ot.her micro-habitats. The degree of t.he locomotory activity was relatively lower when food, water, and other individuals were not supplied t.han when they were supplied. The Pnncipal Component Analysis (PCA) on the presence at the micro-habitats showed that. t.he presence pattern for each mdividual appeared differently (Q mode) while the differem time zones were grouped to the photophase and scotophase (R mode). When food, water, and other individuals were supplied the degree of grouping was higher at the shelter than at the places for feeding and drinking. When the act.ivityand the presence time at the different micro-habitats were jointly analyzed by PCA, the achvity of the female smoky brown cockroach appeared in relation with the presence time ( %) at the places for feeding and other individuals.

• Korean journal of applied entomology
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• v.48 no.4
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• pp.439-445
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• 2009

Species richness (number of species) of the butterfly community in the Gwangneung forest, Korea, was estimated using data of the long-term butterfly monitoring, which had been carried out 291 times in the Korea National Arboretum or forest area of Gwangneung from 1998 to 2008. Abundance of each butterfly species was monitored using the line-transact method. In the present study, 13,333 butterflies belonging to 112 species were observed. Species accumulation curve and species richness was obtained using a software, EstimateS. The species accumulation curve shows an increase tendency even at 291 survey times, implying the possibility of the presence of a few unfound species. However, values of species richness estimated by the seven estimators were stabilized around 240-250 survey times. Species richness estimated by the estimators ranged from 120 species to 141 species with 128 species in average. However, the figure estimated by the previous studies since 1958 was 148 species. We estimated the reasonable scale of species richness on the base of recent analysis on the change of butterfly species. Species richness of the Korea National Arboretum was higher than that of natural forest and of plantation. However, species richness of butterfly was not different between natural forest and plantation. It is likely that increase of grasslands and habitat diversity in arboretum led to the increase of species richness of butterfly community.