• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.3
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• pp.133-142
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• 2009

In order to understand the present environmental condition and future impingement of Changjiang(Yangtze River) outflow upon the adjacent seas after the scheduled completion of the Sanxia (Three Gorges) Dam in 2009, we tried to estimate the mixing ratios among surface waters of three end-members: Changjiang Water (CW), Kuroshio Water (KW), and East China Sea Water (ECSW) using $^{228}Ra/^{226}Ra$ activity ratio and salinity as tracers. Water samples were collected from 32 stations in November 2005 (R/V Tamgu 3), from 20 stations in July 2006 (R/V Ocean 2000) and from 17 stations in August 2006 (R/V Ieodo) in the northern part of the East China Sea. Radium isotopes in ~300 liters of surface seawater were extracted onboard by filtering through manganese impregnated acrylic fibers and following coprecipitation as $Ba(Ra)SO_4$. Activities of radium isotopes were determined by a high purity germanium detector. Results show that the fraction of CW was in the range of 1-23% in the study area, while KW was in the range of 0-30 % and ECSW 58-100 %. The eastward plume of Changjiang outflow, commonly observed in satellite images during summer and also displayed by the eastward-decreasing CW fraction in this study, could be attributed to Ekman transport caused by the SE monsoon prevailing in this region during summer. Results of this study showed that in the drought season, there was a little or no fraction of CW in the study area. Concentration of dissolved inorganic nitrogen (DIN) showed strong positive relationship with the fraction of CW, suggesting Changjiang as the major source of nitrogen. The mixing curve of DIN indicates the removal of nitrate by biological uptake during the mixing of CW with ambient seawater in the study area.

• Journal of Aquaculture
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• v.14 no.3
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• pp.181-195
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• 2001

To stabilize the lantern cage culture system of Patinopecten yessoensis(Jay) in the eastern coast of Korean peninsula, optimum conditions such as time of transplantation, rearing density and depth, and time of harvest were identified. During the period from January 1991 to December 1998, the water temperature ranged from 4.7 to 21.4$^{\circ}C$ at 15-30 m depth and 4.9 to 25.7$^{\circ}C$ at the surface; these thermal ranges were within the optimal ranges (5-23$^{\circ}C$) prevailing at 15-30 m depth at surface water. Annual thermal changes indicated that the prevailing temperature during the years 1993 and 1996 was near optimum, but higher during the years 1994, 1997 and 1998, when mass mortality and growth retardation occurred. Salinity (32.0- 34.4$\textperthousand$) and dissolved oxygen (4.14 -8.11 $\mu\textrm{g}$/l) at 15 m depth were well within the optimum ranges. The chlorophyll concentrations (0.06 - 2.73$\mu\textrm{g}$/l) indicated that the study area was oligotrophic, although mass mortality did occur, when chlorophyll concentrations were high, especially in summer. Hence water temperatures and chlorophyll concentration are major factors related to survival and growth of the scallop. In terms of the shell height maximum growth occurred during spring (March-May; 8 - l3$^{\circ}C$) and fall (October-December; 11-l7$^{\circ}C$) in the lantern cage culture. Slow growth was recorded during late winter January-february; less than 7$^{\circ}C$) and mid-summer (August- September; more than 18$^{\circ}C$). Daily growth of shell height and total weight were 0.02∼0.24 mm and -0.07∼0.90 g at the rearing density of 12 individuals per net. Optimal .earing density in the lantern cage (ø50${\times}$20 cm) was 10∼15 individuals with the shell height of 5∼6 cm. The fastest growth rates were observed at 15∼20 m depth; however, it is recommended that 20∼30 m would be optimal. The scallops require 22 months to attain the commercial size of 10 cm shell height and 140 g total weigh, and are best harvested and sold during March-April.

• Food Science and Preservation
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• v.19 no.2
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• pp.193-200
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• 2012

The quality characteristics of $kalopanax$ $pictus$ and Aralica elata shoots during their preservation were investigated according to the salt conditions and storage temperatures to improve the use of the shoots. The results were as follows: the pH of $kalopanax$ $pictus$ shoots duing their storage did not changes with 10% and 12% brine at $4^{\circ}C$ and with 12% brine at $10^{\circ}C$. The pH of $Aralica$ $elata$ shoots is at $4^{\circ}C$ tended to be similar to the $kalopanax$ $pictus$ shoot and decreased at the storage temperature of $10^{\circ}C$. The salinity of the $kalopanax$ $pictus$ and $Aralica$ $elata$ shoots tended to increase during their storage and did not change significantly as their storage temperature changed. The L values of $kalopanax$ $pictus$ and $Aralica$ $elata$ shoots tended to decrease gradually during their storage, and the salt concentrations appeared high. The b value of the $kalopanax$ $pictus$ shoot tended to increase and that of the $Aralica$ $elata$ shoots, to decrease gradually. The a value tended to increase gradually but did not differ with variations in the storage temperatures and salt concentrations. The strength and the hardness of the $kalopanax$ $pictus$ and $Aralica$ $elata$ shoots tended to decreased gradually during their storage and highest in 10% brine at $4^{\circ}C$, and those of $Aralica$ $elata$ shoots were highest in 8-10% brine at $4^{\circ}C$. The Chlorophyll contents of the $kalopanax$ $pictus$ and $Aralica$ $elata$ shoots tended to decrease during their salt storage and did not change significantly as the temperatures and salt concentrations changed. Therefore, it can be concluded that the quality of $kalopanax$ $pictus$ and $Aralica$ $elata$ shoots can be maintained when the are stored in 10% brine at $4^{\circ}C$.

• Journal of Korean Society of Forest Science
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• v.104 no.4
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• pp.564-577
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• 2015

The objectives of this study were to investigate the possibility of establishing a tree nursery at Saemangeum reclaimed land and to classify landscape trees based on the salt tolerance. A tree nursery (2.0 ha) was made in Gunsan Okgu area in 2012 with underground drain lines on the reclaimed land established in 2010. Salt content of the nursery soil within the 60 cm depth in 2013 was 5.13 dS/m and 8.20 dS/m for the pre-desalinated and non-desalinated lands, respectively. Thirty-six woody plant species (22 tree species and 14 shrub species at ages of 1 to 4) with a total of 3,943 individuals were planted in early April, 2013 and their growth performance was monitored until September of the same year. The average survival rate of the transplanted plants was 71.4% in late September, suggesting the high possibility of establishing a tree nursery at the reclaimed land. Based on the survival rate and tree vigor (amount of healthy leaves and crown development), the following 17 species with some salt tolerance were classified into three groups: "salt tolerant group" (3 species, Tamarix chinensis, Cudrania tricuspidata, Ilex serrata), "recommended group" (5 species, Pinus thunbergii, Albizia julibrissin, Ligustrum obtusifolium, Rosa rugosa, Pleioblatus pygmaeus), "plantable group" (9 species, Zelkova serrata, Hibiscus syriacus, Elaeagnus umbellata, Sorbus alnifolia, Sophora japonica, Metasequoia glyptostroboides, Quercus acutissima, Ulmus parvifolia, Robinia pseudoacacia). Seven tree species that had been adapted to the reclaimed land for three to four years before being transplanted to new reclaimed land in Gunsan Okgu area showed average survival rate of 98%, suggesting that pre-conditioned trees would survive well in the reclaimed land.

• Journal of Life Science
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• v.23 no.12
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• pp.1454-1459
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• 2013

This study investigated the effects that water temperature and the administration of estradiol-17${\beta}$ (E2) had on the sex ratio and growth of the Japanese eel, Anguilla japonica. Glass eels (total length${\fallingdotseq}$6.5 cm) were differentiated into an E2 group and an E2-free group and then they were reared for about four months at three water temperature levels of $20^{\circ}C$, $24^{\circ}C$, and $28^{\circ}C$. The results showed that the young eels survived normally at the rearing water temperature of ${\geq}24^{\circ}C$, and grew to a mean size of 20 cm (total length). In the E2-free group, temperature was not found to increase the sex ratio (feminizing rates); however, the sex ratio of the E2-administrated group was found to be a little higher at a high temperature ($28^{\circ}C$). The growth of the E2 group was lower than the growth of the E2-free group at $24^{\circ}C$ and the E2 concentration levels in the plasma at $24^{\circ}C$ were found to be significant after the end of the E2 administration period (178 days). Therefore, we thought that long-term administration of E2 must be considered to be the reason for growth decline in spite of the prominent sex ratio effect. Our results indicate that temperature was not related to an increase in the feminizing rate (sex ratio) in the Japanese eel, Anguilla japonica, and other environmental factors (rearing density, salinity, etc.) that have the possibility of inducing ovarian differentiation must be investigated.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.370-379
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• 2002

The composition of extractive nitrogenous constituents in four species of commercial marine seasoned-dried products (SDP) and five species of seasoned-dried and roasted products (SDRP) were analyzed. The extractive nitrogen contents were $688{\sim}1,124$ and $756{\sim}1,099\;mg/100g$ in SDP and SDRP extracts. Contents of Free amino acids such as glutamic acid, taurine, arginine, proline, alanine, and histidine were high in all samples. The combined amino acid amounted to $662{\sim}2,248$ and $1,146{\sim}1,821\;mg/100g$ in SDP and SDRP, respectively, which corresponded to 34.5 and 42.5% of the total free amino acid level. ATP and related compounds were $3.69{\sim}7.37$ and $2.17{\sim}8.45\;{\mu}mol/g$ in SDP and SDRP, respectively. Five types of betaines were detected in both specimens although in small amounts. TMAO, TMA, creatine, and creatinine were detected in both samples, however they have same variation in each sample. There was no significant difference in the extractive nitrogenous constituents between SDP and SDRP except in moisture, salinity, and contents of glutamic acid and creatinin (p<0.01).

• Journal of agriculture & life science
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• v.44 no.2
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• pp.39-48
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• 2010

In order to develop the high quality kanjang in which a functionality is strengthened, the physicochemical properties and antioxidant activities of Korean traditional kanjang and garlic-added kanjang were compared and analyzed. Of color, lightness (L) and redness (a) value were not significant difference between a sample, but yellowness (b) value was higher than garlic-added kanjang. Moisture and crude protein contents were not significantly different, content of crude lipid and ash was higher than traditional kanjang. The pH were 5.02 and 4.91 in traditional and garlic-added kanjang, respectively. The salinity was $20.97{\pm}0.15%$ in garlic-added kanjang, that was significantly lower in garlic-added kanjang. The reducing sugar and total sugar contents were significantly higher in garlic-added kanjang. Na content was occupies 87~89% of total mineral content. The contents of total amino acids were 1,564.02 mg% and 1,932.41 mg% in traditional and garlic-added kanjang, respectiveluy. Also free amino acid was higher in garlic-added kanjang (484.43 mg%) than traditional kanjang (461.13 mg%). The antioxidant activities were increased in a does-dependent manner. In $100{\mu}L/mL$ concentration, electron donating abilities were $14.43{\pm}0.25%$ and $54.6{\pm}1.48%$ in traditional and garlic-added kanjang, ABTs radical scavenging activities of garlic-added kanjang was $57.21{\pm}1.34%$ that was higher than traditional kanjang ($43.27{\pm}0.19%$).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.2
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• pp.124-134
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• 2021

Water in the Mulgol pond on Dokdo (island), Korea, was historically used for drinking water, but now it has been no longer used for this purpose due to regionally low water quality. Since 2007, this pond has been covered with a metal lid to protect from pollutants of seabirds, indicating limited light penetration into the Mulgol pond. Here, we investigated water quality in the pond and potential relationships of nitrogen components and microbes in May, June, August, and November 2020. The source salinity ranged from 1.39 to 1.57 psu. Suspended solids (0.8~5.1 mg L^-1) and chlorophyll-a (<0.01~0.49 ㎍ L^-1) remained low. The concentration of dissolved inorganic nitrogen (DIN) was between 35.9 and 47.2 mg L^-1. Thus, water in the Mulgol pond proves to be brackish water with low chlorophyll-a and high nutrients. This unique environment may be established by limited light intensity, sea fog (or seawater), and fecal pellets from many seabirds. Although the light source (800~8000 lux) was exposed to the four subsamples, chlorophyll-a concentrations were below <0.5 ㎍ L^-1 during the incubation periods. This result suggests that the biomass of phytoplankton does not increase along with an increase in light intensity. Furthermore, the content of nitrate constituted more than 90% of DIN, and a significant negative correlation between nitrate concentration and bacterial abundance was shown in May and June 2020 during the light exposure experiments (R=-0.762, p<0.05). Thus, it is possible that bacteria may be a significant agent to reduce nitrate concentration in the Mulgol pond, the relationship between nitrate concentration and bacterial abundance may vary seasonally.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.431-438
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• 2021

To prepare more stringent regulations for USCG Phase II ballast water management, this study investigated the staining efficiency of SYBR Green I(SGI) and SYBR Gold(SG) on the virus-like particle (VLP). A dye with high staining efficiency was applied to the treated water that was passed through the ballast water treatment system (BWTS). VLP staining was observed most clearly under the 100-fold and 200-fold dilution of the stock solution when the volume of filtered samples was 0.5 mL to 2 mL. The staining efficiency of SGI and SG did not show a significant difference. On the other hand, the green fluorescence of viruses in the sample stained with SGI was more pronounced than in the samples stained with SG (expressed yellow fluorescence), making it easier to observe. The abundance of VLP in the test water and control water treatments that did not pass through the two types of BWTS (electrolysis type, UV + electrolysis type) was approximately 109 - 1010 VLP 100 mL-1. In contrast, no stained VLP was observed in the treated water treatments. Moreover, SGI was confirmed to be effectively stained under various salinity conditions, including seawater, brackish water, and freshwater. Further verification tests and development of staining methods under various BWTS are required, but the SGI staining method is believed to be a good alternative to the VLP live/dead determination of the USCG Phase II type approval test.

• Korean Journal of Environmental Biology
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• v.40 no.1
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• pp.112-123
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• 2022

To assess the influence of environmental factors on the phytoplankton community structure and total phytoplankton biomass during four seasons in 2014, we investigated the abiotic and biotic factors at 25 stations in the Busan coastal region. The phytoplankton community and total phytoplankton biomass were strongly dependent on the discharge from the Nakdong River, and the high density of phytoplankton was related with the introduction of the Tsushima Warm Current (TWC), particularly in the thermohaline fronts of the fall season. The relationship between the salinity and nutrient (Dissolved inorganic nitrogen=DIN: R²=0.72, p<0.001 and Dissolved inorganic silicon=DSi: R²=0.78, p<0.001) highly correlated with the river discharge, implying that those nutrients have played a crucial role in the growth of diatom and cryptophyta. The total phytoplankton biomass was highest in the summer followed by autumn, spring, and winter. Diatom and cryptophyta species were dominant species during the four seasons. Additionally, there were strong positive correlations between Chlorophyll a and total phytoplankton biomass (R²=0.84, p<0.001), cryptophyta (R²=0.76, p<0.001) and diatom (R²=0.50, p<0.001), respectively. In particular, we found that there were significant differences in the nutrients, phytoplankton community compositions, and total phytoplankton biomass between the inner and the outer coastal region of Busan, depending on the amount of river discharge from the Nakdong River, particularly during rainy seasons. Therefore, the seasonal change of TWC and river discharge from the Nakdong River serve an important role in determining phytoplankton population dynamics in the Busan coastal region.