• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.5
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• pp.486-494
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• 2003

Distribution of ichthyoplanktons and its relation to environmental factors (temperature, salinity, $chlorophyll\;\alpha$) around the Youngsan River Estuary of Mokpo, southwest coast of Korea were investigated based on the samples collected bimonthly from February to December, 2001. Unidentified fish eggs were most abundant $1,345\;eggs/100m^3$ in August, while eggs of Engraulis japonicus were most abundant $63\;eggs/100m^3$ in June. A total of forty species of fish larvae and juveniles belonging to the twenty families under six orders were caught, with six gobiids, four icefishes, four croakers and three herrings being represented. Fish larvae and juveniles peaked $17,757\;inds./100m^3$ in August, which consisted of $91.02\%$ of gobiids, $3.69\%$ of gunnels and $3.67\%$ of icefishes, and they were most abundant $7,467\;Inds./100m^3$ at St. 7. Cluster analysis based on the individuals of fish larvae and juveniles showed that six months were classified into two groups at the dissimilarity 70, the first was composed of June and August and the second was February and December and April and October were not clustered with any other months. In August when species diversity index was the highest, eight stations were classified into two groups at the dissimilarity 70, the first was composed of St. 1, 3, 4, 5 and 8 and the second was St. 6, 7 and 2. As a result from correspondence analysis, there is no effect of the environmental factors with a density of fish eggs and larvae, but correlation could be found between a density of fish eggs and $chlorophyll\;\alpha.$

• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.97-104
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• 2016

This paper performed consolidation tests on soft ground with and without artesian pressure conditions to find out characteristics of leaching effects using two types of one-dimensional column equipment(height : 1,100mm, outer diameter : 250mm). Artesian pressure of 5.5kPa was applied to the bottom of soft ground inside column equipment. Distribution of salinity and shear strength with soil depth were measured after the consolidation test. From the results, it was found that distribution of undrained shear strength and salt concentrations were similar at the top of clay ground irrespective of artesian pressure condition. However, at the bottom of clay ground, the values of undrained shear strength and salt concentration under artesian pressure were lower than those without artesian pressure. This result indicates that structure of soft soil with artesian pressure was weakened by salt leaching. Electronic resistance results showed that void ratio under artesian pressure condition was more reduced than that without artesian pressure condition.

• Journal of Life Science
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• v.30 no.2
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• pp.186-190
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• 2020

Halophytes are physiologically adapted to withstand the high salinity of water and saline soil. This study was conducted to elucidate the distribution of halophytes and hydrophytes in the Jungseonpo River (Sacheon-ci, Gyeongsangnam-do), Gwingok River (Hadong-gun, Gyeongsangnam-do), and Gwangyangseo River (Gwangyang-ci, Jeollanam-do) in Korea. A total of six species of halophytes and ten species of hydrophytes were collected in the Jungseonpo River. Halophytes in the Gwingok River and Gwangyangseo River numbered five species and 11 species, respectively. Hydrophytes in the Gwingok River and the Gwangyangseo River numbered 13 species in five families and 16 species in eight families, respectively. Of these, Phacelurus latifolius, endemic to the west and south coast of Korea, is an endangered species in the context of investigating the ecology and conservation of halophyte species. Many individual halophyte species have been diminished due to reduced habitable area caused by sand dune destruction. The rivers in the three areas on the south coast were also different in terms of distribution of salt plants due to regional differences, and they were all different from the well-developed west coast. Seven species, including Rosa wichuraiana, have been added to South coasts compared to past records.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.3
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• pp.50-61
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• 2008

Environmental factors and phragmites growth properties at various habitats in Eulsukdo ecological park were investigated to understand major factors affecting phragmites distribution in constructed wetlands. Although phragmites is very important species in wetland ecosystem, it should be controlled to prevent excessive expansion within the restricted park area. The results showed that phragmites dominant sites have the highest LAI among other emerged plants habitats and could adversely affect for waders habitats. Phragmites were also found at the areas with wide ranges of water-depth than other plants, and showed phragmites could be favored for occupying the newly constructed wetlands like Eulsukdo ecological park. The results showed difference in soil redox potential between phragmites dominant and non-dominant sites. Because soil redox potential is affected by wetland hydrology like flooding duration, control of wetland hydrology should be considered for creation and management of constructed wetlands. The results also showed that differences in soil cation exchange capacity, soil salinity, soil organic matter content and site inclination between phragmites dominant and non-dominant sites as well as brackish and freshwater areas. Those abiotic factors can be important considerations for the sustainable wetland management especially for the phragmitest managements in the ecological park.

• Ocean and Polar Research
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• v.27 no.4
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• pp.463-476
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• 2005

Mesozooplankton samples were collected to investigate the spatial distribution in the Chuuk lagoon of the Federated States of Micronesia through three surveys from 2002 to 2004. Average temperature was $28.70^{\circ}C$ in August 2002, $30.17^{\circ}C$ in October 2003 and $29.18^{\circ}C$ in July 2004 at a water depth of 2rn. Average salinity was 33.95 psu in August 2002, 33.56 psu in October 2003 and 33.77 psu in July 2004. Total rnosozooplankton consisted of 70 taxa during the study period, among which copepods were the most diverse group. Foraminiferans, radiolarians, copepods and appendicularians, which comprised about 70% of total zooplankton abundance, were important components in the zooplankton community. Within the copepod group, Acartia spp., Centropages spp. and Undinula spp. were dominant in August 2002, Acartia spp., Centropages spp., and Oithona spp. in October 2003, and Acartia spp., Undinula spp., and Oithona spp. in July 2004. Total zooplankton abundance was high around Weno Island, while low in stations located in the northern part of Weno Island. High abundances of appendicularians were found in the southern part of weno Island as well as around Weno Island. Appendicularians foraminiferans, radiolarians, Sagitta spp. and immature copepods accounted for most of the distribution pattern of the mesozzoplankton community throughout the study area. These results suggest that appendicularians may be potential food items for fish larvae around Weno Island in the Chuuk lagoon states.

• Journal of Korean Society on Water Environment
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• v.35 no.2
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• pp.165-180
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• 2019

Water quality data of 81 lakes in Korea, 2013 ~ 2017 were analyzed. Most water quality parameters showed left-skewed distribution, while dissolved oxygen showed normal distribution. pH and dissolved oxygen showed a positive correlation with organic matter and nutrients, which appeared to be a nonsense correlation mediated by the algae. The ratio of $BOD_5$ and $COD_{Mn}$ to CBOD was 21 % and 52 % in the freshwater lakes, respectively. TOC concentration appeared to be underestimated by the UV digestion method, when salinity exceeds $700{\mu}S\;cm^{-1}$. In terms of nitrogen/phosphorus ratio, the limiting factor for algal growth seemed to be phosphorus in most of the lakes. Chlorophyll ${\alpha}$ increased acutely with decrease of N/P ratio. However, it seemed to be a nonsense correlation mediated by phosphorus concentration, since the N/P ratio depended on phosphorus. The N/P ratio of brackish lakes was lower than that of the freshwater, at the same concentration of phosphorus. It is worth examining denitrification that occurs, in bottom layer and sediment, during saline stratification. $Chl.{\alpha}$ concentration decreased in the form of a power function with increase of mean depth. The primary reason is that deep lakes are mainly at the less-disturbed upstream. However, it is necessary to investigate the effect of sediment, on water quality in shallow lakes. Light attenuation in the upper layer, was dominated by tripton (non-algal suspended solids) absorption/scattering (average relative contribution of 39 %), followed by CDOM (colored dissolved organic matter) (average 37 %) and $Chl.{\alpha}$ (average 21 %).

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.406-414
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• 2022

Bolboschoenus planiculmis has been acknowledged as a key species in whooper swans (Cygnus cygnus) habitat by providing food for this migratory waterfowl. B. planiculmis wetlands are being degraded by water shortages and salinization caused by anthropogenic activities and climate changes. In 2004, the distribution of B. planiculmis in the tidal flats of the Nakdong Estuary was 2,475,568 m², and in 2021, the distribution area was 798,731 m², which decreased by 32.3%. In order to restore the degraded B. planiculmis wetlands, shoot transplantation and seed sowing were tentatively used in three places with different salinity and water levels. The average density per unit area in September at the optimal growth period after planting were A (fresh water level 50 cm) 58±15.65 m^-2, B (brackish water level 0~5 cm) 188±63.83 m^-2, C (brackish water level 0 cm or less) 188±45.13 m^-2. The tubers were observed as A 0 g dw m^-2, B 25.32±2.94 g dw m^-2, and C 13.39±0.91 g dw m^-2. Tubers were distributed in the soil, with only 3.0% at the 10~20 cm depth but 97.0% at the 0~10 cm depth. In contrast, the germination rate of B. planiculmis seeds was observed to be 0%. Results of this study provide technical support for the restoration of B. planiculmis wetland and the improvement in the quality of whooper swans habitat.

• Food Science and Preservation
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• v.24 no.1
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• pp.36-43
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• 2017

The aim of this study was to provide the quality index of salted Korean cabbage in a short-term distribution system. Salted Korean cabbages were packaged with or without 2% salt water, and then distributed in a conventional system (CVS) and a cold-chain system (CCS) for 6 h. The material temperature of samples with and without salt water gradually increased to $19.57^{\circ}C$ and $19.43^{\circ}C$ in a CVS, respectively and to $10.73^{\circ}C$ and $12.90^{\circ}C$ in a CCS, respectively. Salinity of the materials in a CCS did not change, whereas salinities of the materials in a CVS were 1.2 and 1.7 fold higher, respectively. Also, a slight increase in acidity was observed in both packaging materials in a CCS. In the case of a CVS, total aerobic bacteria and lactic acid bacteria increased to 7.62 log CFU/g and 6.77 log CFU/g in the materials with salt water, respectively, whereas the number of total aerobic bacteria and lactic acid bacteria ranged between 5.62-5.85 log CFU/g and 4.33-4.83 log CFU/g in the materials without salt water, respectively. However, significant microbial changes were not observed in a CCS as distribution time increased. CCS with salt water packaging was effective in achieving microbial control and maintaining physicochemical quality. Salinity, aerobic bacteria, and lactic acid bacteria can be useful as quality indices for a CVS, and acidity can be useful as quality index for a CCS.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.288-293
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• 2018

This study was conducted to understand the characteristics of the seasonal and regional distribution of phytoplankton communities in the Fisheries Resources Protection Area of Korea (FRPA). We investigated the phytoplankton composition, abundance and dominant species collected from five different regions (Cheonsu, Tongyeong-I, Tongyeong-II, Hansan, and Jindong) in 2016. According to the results, most environmental parameters, such as temperature, salinity and nutrients, showed statistically significant seasonal differences. Suspended particulate material (SPM) only showed a statistically significant regional difference. The mean abundance of phytoplankton ranged from 13 to $4,062cells{\cdot}ml^{-1}$, with large spatio-temporal fluctuations. In particular, the bloom of phytoplankton (>$10^3cells{\cdot}ml^{-1}$) in Cheonsu Bay occurred in April and October with Skeletonema spp. and Chaetoceros socialis being the dominant species during these two seasons, respectively. The dominant species in the FRPA were diatoms (Pseudo-nitzschia spp., Skeletonema spp., and Chaetoceros pseudocriniuts) and dinoflagellates (Scrippsiella trochoidea and Tripos furca). The seasonal distribution of phytoplankton communities showed typical characteristics of coastal waters, i.e., that diatoms usually dominated in winter and autumn, while dinoflagellates tended to dominate in spring and summer. Meanwhile, the dominance rate of diatoms in the phytoplankton community in Cheonsu Bay, which is located in a high-turbidity region, was 9~27 % greater than that of diatoms in the phytoplankton community found in the south coastal waters, which is a low turbidity region.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.717-724
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• 2011

The objectives of this study were to analyze environment in the forest and growth characteristics for investigating the characteristics of Robinia pseudoacacia distribution in a Pinus thunbergii forest at the coast. As a result of analyzing inhibitory factors of Robinia pseudoacacia distribution in a Pinus thunbergii forest at the coast, it is considered that the salt level included in a sea wind is supposed to be the primary factor of the slow growth for Robinia pseudoacacia since brown leaves, wilting and early leaf fall have appeared in the 0m spot from the artificial dune which has the high salt level. However, the soil properties and light environment hardly have a effect on the growth of Robinia pseudoacacia because there is no difference among planting places. Also, the growth ring of the horizontal root in 2year individuals 0.1~0.2m away from the dune have been formed for 1 year only as a consequence of analyzing growth rings of Robinia pseudoacacia growing on the coast. It can be infered that the nourishment of the horizontal root from individuals growing on the coast have been provided for the first 1 year only. It is estimated that, in case of the nearby areas on the coast, it is not enough to provided nourishment to the horizontal root due to obstructing the growth of new individuals by a sea wind, so the growth of the horizontal root would be hampered. Therefore, it is considered that impedient Robinia pseudoacacia distribution in a Pinus thunbergii forest at the coast is caused by making no growth of new horizontal roots and newborn individuals.