• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.33 no.4
• /
• pp.321-333
• /
• 1997

This paper describe on the transmitting/receiving functions and the monitoring effects for the telemetry system which is designed to monitor the environmental condition of a culturing fishery ground inside a bay. The telemetry experiments were carried out by the telemetry system which constructed with the sea water temperature/salinity measuring sensor and telesounder at culturing fishery ground located in the coast of Sangyang-Myon, Kyongsangnam-Do province from October, 1995 to May, 1996. The results of this experiment showed that the developed telemetry system could be used for monitoring the sea water temperature/salinity and the distribution of fish in culturing fishery ground.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.43 no.5
• /
• pp.406-414
• /
• 2010

The impact of rainfall events on the sanitary indicator bacteria density of the shellfish-growing waters in Geoje Bay and Jaran Bay in Korea was investigated. The shellfish-growing area in Geoje Bay, which is a nearly closed basin, was not affected significantly, except near the stream mouth after 11.5 mm of rainfall in 1 day. However, most of the shellfish-growing water in the bay was polluted by fecal coliform bacteria after rain as heavy as 43.0 mm, and the levels of fecal indicator bacteria in some of the sea near the coast did not recover completely until 24 hours after the rainfall. By contrast, in Jaran Bay, which has no significant pollution source in the drainage area, although 9.3-490 MPN/100 mL of fecal coliform bacteria were detected near the stream mouth after rainfall of 33.5 and 81.0 mm, a very low level of the indicator bacteria was detected in the designated shellfish-growing area. During the investigation, the correlations between the sanitary indicator bacteria density and physical parameters, such as salinity and turbidity, were evaluated. Both the total coliform and fecal coliform densities were inversely correlated with salinity. Turbidity was positively correlated with the indicator bacteria density. The survey results suggest that for more efficient management of the shellfish-growing areas located in coastal areas, such as shellfish harvesting after rainfall, a detailed investigation of the effects of rainfall on the bacterial water quality in each growing area is needed.

• Journal of Life Science
• /
• v.26 no.2
• /
• pp.164-173
• /
• 2016

Isotocin (IT), a nonapeptide homolog of oxytocin in mammals, has been suggested to be involved in physiological processes including social behaviors, stress responses, and osmoregulation in teleost fish. To study its structure and function, the gene encoding the IT precursor was cloned from the genomic DNA and brain cDNA of the cinnamon clownfish, Amphiprion melanopus. The IT precursor gene consists of three exons separated by two introns, and encodes an open reading frame of 156 amino acid (aa) residues, comprising a putative signal peptide of 19 aa, a mature IT protein of 9 aa, a proteolytic processing site of 3 aa, and 125 aa of neurophysin. Tissue-specific analysis of the IT precursor transcript indicated its expression in the brain and gonads of A. melanopus. To examine its osmoregulatory effects, the salinity of the seawater (34 ppt) used for rearing A. melanopus was lowered to 15 ppt. Histological analysis of the gills indicated the apparent disappearance of an apical crypt on the surface of the gill lamella of A. melanopus, as pavement cells covered the surface upon acclimation to the lower salinity. The level of Na⁺/K^+-ATPase activity in the gills was increased during the initial stage of acclimation, followed by a decrease to its normal level, suggesting its involvement in osmoregulation and homeostasis. The only slight increase in the level of IT precursor transcript in the A. melanopus brain upon low-salinity acclimation suggested that IT played a minor role, if any, in the process of osmoregulation.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.9
• /
• pp.322-328
• /
• 2016

This study investigated the effects of temperature, salinity, and algal diet to find the optimal conditions for 5 days for the mass culture of the tropical tintinnid, Metacylis tropica. This tintinnid had a small, hyaline, and ovoid lorica. The oral diameter, length, and maximum width of the lorica were $36.7{\mu}m$, $49.5{\mu}m$, and $44.5{\mu}m$, respectively. In the temperature experiments, the highest maximum density and population growth rate were observed at $30^{\circ}C$ with 340.7 cells/mL and 1.1/day, respectively. Lower salinities adversely affected the population growth of M. tropica. The maximum density was observed at 33 ppt (840 cells/mL). In the diet experiments, M. tropica fed Isochrysis galbana showed the highest density (413 cells/mL) and population growth rate (1.2/day). As a result, M. tropica is appropriate as a potential prey organism for early fish larvae with smaller mouths because the tintinnid has a relatively small size compared to the rotifer. In addition, the conditions of $30^{\circ}C$, 33 ppt and supplying I. galbana would be effective in the cultivation of M. tropica.

• Korean Journal of Environmental Biology
• /
• v.40 no.3
• /
• pp.290-300
• /
• 2022

A strain of Alexandrium species was established by isolating cells from Jangmok Bay, Korea. Its morphology and molecular phylogeny based on LSU rRNA gene sequences were examined. In addition, growth responses of this Alexandrium species to changes in temperature, salinity, and nutrient concentrations were investigated. This Alexandrium species from Jangmok Bay had a ventral pore on the 1', which was morphologically consistent with previously described Alexandrium tamarense and A. catenella. Phylogenetic analyses revealed that this isolate was assigned to A. pacificum (Group IV) within A. tamarense species complex. In growth experiments, relatively high growth rates and cell densities of A. pacificum (Group IV) were observed at 15℃ and 20℃. This species also grew under a wide range of salinity. This indicates that this Korean isolate of A. pacificum (Group IV) is a stenothermic and euryhaline species. In growth responses to changes in nutrient levels, enhanced growth rates and cell densities of A. pacificum(Group IV) were observed with additions of nitrate and phosphate. In particular, rapid uptakes of phosphate by A. pacificum (Group IV) were observed in experimental treatments, indicating that the increase in phosphate concentration could stimulate the growth of A. pacificum(Group IV).

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.5B
• /
• pp.519-524
• /
• 2010

This study was carried out to select suitable plants for beach revegetation as a preliminary study for quantifying the effect of decreasing sand movement. After planting some herbal plants in field, monitoring of temporal change of vegetation coverage which was index of the growth rate was conducted. Through literature reviews, 24 candidate plants for beach revegetation were selected, then seven species of them, Peucedanum japonicum Thunb., Dianthus japonicus Thunb. ex Murray, Sedum oryzifolium Makino, Sedum takesimense Nakai, Sedum spectabile Boreau, Farfugium japonicum (L.) Kitam., Aster sphathulifolius Maxim. were picked through salinity tolerance experiments in laboratory. Seven species selected by salinity tolerance experiments and two additional herbal plants, Prunella vulgaris var. lilacina Nakai and Linaria vulgaris Mill., not the candidates, were nine final species which were planted in the beach around Osan port, Uljin, Korea. The changes of vegetation coverage of each species were investigated from photos periodically taken for about a year using image processing methods. As a result of the monitoring, Sedum takesimensei, Dianthus japonicus and Aster sphathulifolius were observed with high coverages during the whole monitoring while Prunella vulgaris var. lilacina and Linaria vulgaris were observed with low coverage during the same period. Consequently, Sedum takesimensei, Dianthus japonicus and Aster sphathulifolius were concluded as the most suitable plants for beach revegetation. Furthur study to quantify the effects of decreasing sand movement by the selected species is needed.

• Korean journal of food and cookery science
• /
• v.26 no.1
• /
• pp.62-71
• /
• 2010

The followings describes the result of making doenjang with added licorice (Glycyrrhiza uralensis) powder. and investigating its sensory characteristics and physicochemical quality. General preference was high at 20% salinity and 2% licorice (LD204), and 16% salinity and 2% licorice (LD162). The moisture content was unchanged in the control group, while it was reduced in LD204 and LD162 in the first week of fermentation, but showed little change after then. pHs were all in the range 5.90~5.97 on day 0, but decreased from 5.90 to 5.72 in the control group in the fifth week. LD204 changed from 5.95 on day 0to 5.42 in the first week, and then it gradually increased again and became 5.93 in the fifth week, which was similar to that of day 0. LD162 was 5.97 on day 0 and showed cyclic slight increases and decreases in the first week. It increased to 6.32 in the fifth week, which was higher than that of day 0 that is, its pH was higher than that of LD204. The acidity showed a difference right after it was made. In the control group, lactic acid content gradually increased from 0.16% on day 0 to the highest, 0.59%, in the fourth week. It slightly decreased in the fifth week. LD204 slowly increased from 0.25% on day 0 to a maximum, 0.50%, in the fourth week. It also slightly decreased in the fifth week, quite similarly to that of the control group. LD162, gradually increased from 0.22% on day 0 to the highest, 0.49, in the third week, and decreased after the fourth week. Salinity was 29.5%, 22.0%, and 18% in each of the control group, LD204, and LD162 on day 0 but increased to 34.0%, 29.0%, and 26.0% in the fifth week. Soluble solid was $32^{\circ}Brix$, $28^{\circ}Brix$, and $26^{\circ}Brix$ in each of the control group, LD204, and LD162 on day 0, but slightly increased to $40^{\circ}Brix$, $32^{\circ}Brix$, and $30^{\circ}Brix$ on the fifth day. It is thought that because of the sweetness of licorice, the higher-salinity doenjang earned a higher sensory test score than that of traditional doenjang. If its salinity is lowered a little, it could be used as a sauce, even possibly having medical effects as well.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.4
• /
• pp.362-371
• /
• 2016

The distribution patterns of Chromophoric Dissolved Organic Matter (CDOM) and the chemical characteristics of CDOM in the Seomjin river estuary were investigated in March, June and July 2012 in order to determine the spatial and temporal variability of CDOM along the salinity gradient considering the effects of mixing, nutrients and Chl a. The average CDOM values were $1.0{\pm}0.3m^{-1}$, $1.3{\pm}0.4m^{-1}$, and $1.4{\pm}0.3m^{-1}$ in March, June and July, respectively. A high concentration of CDOM (greater than $1.5m^{-1}$) was found at the head of the river which decreased towards the river mouth to as low as less than $0.5m^{-1}$. The average concentrations of CDOM increased from the dry season (March and June) to the wet season (July), and the average slope values ($S_{300-500}$), which were used as indicators of CDOM characteristics and sources, were in the range of $0.013-0.018m^{-1}$. The CDOM and $S_{300-50}$ values showed that not only the concentration of CDOM but also the chemical properties of DOM clearly changed between upstream and downstream in the Seomjin river. CDOM and FDOM showed a negative correlation with salinity ($R^2$ > 0.8), and CDOM was positively correlated with FDOM. Furthermore, the mixing pattern of CDOM was confirmed as conservative for all seasons. The main environmental factors influencing the concentration of CDOM was confirmed as conservative for all seasons. The main environmental factors influencing the concentration of CDOM were salinity (mixing) and water temperature, which meant the dilution of low CDOM seawater, was the controlling factor for the spatial distribution of CDOM. Increases in water temperature seemed to induce the production of CDOM during summer (June and July) through the biological degradation of DOM either by microbial activity or photo-degradation.

• Journal of Aquaculture
• /
• v.7 no.1
• /
• pp.21-39
• /
• 1994

In order to study the optimum environmental condition for larvae culture of the freshwater crab, Eriocheir japonicus, larvae from different growth stages and young crab were cultured under the 16 different conditions of $4\times4$ temperature-salinity combinations (4 different temperatures at 22, 24, 26, $28^{\circ}C$ with 10.5, 17.5, 24.5 and $31.5\%$ of salinity). The duration of metamorphosis, metamorphosis rate, the interval of moulting period, and survival rate were measured from each experimental group of larvae and young crab under the different conditions. The results indicated that the optimum conditions may be a $24.5\%o$ of salinity at water temperature at 22, 24, and $26^{\circ}C$. At $28^{\circ}C$ with $24.5\%o$), the duration of metamorphosis reduced somewhat, nevertheless metamorphosis and survival rate decreased a lot. And the lower the salinity showed the lower the metamorphosis and survival rates at $28^{\circ}C$.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.26 no.2
• /
• pp.5-13
• /
• 2024

This study was conducted to investigate the effect of salinity stress on the antioxidant and anti-inflammatory activities of Crepidiastrum sonchifolium. The plant was treated with NaCl at concentrations of 0, 50, 100, and 200mM for 6 weeks. After treatment, the whole plant was collected, and 70% ethanol extracts were prepared. The DPPH radical scavenging activity was highest in the order of NaCl treatment concentrations of 0, 100, and 50mM, while the 200mM treatment group showed the lowest radical scavenging. The total phenol and total flavonoid contents showed very similar results to the antioxidant activity depending on the NaCl concentration, confirming that the phenolic compounds of the plant can contribute to the antioxidant capacity against salinity stress. In addition, the investigation of the effect of NaCl-treated C. sonchifolium extract on the inhibition of NO production in the LPS-stimulated mouse macrophage cell line (Raw 264.7) revealed that NO production significantly decreased in the 1,000㎍/mL treatment group across all NaCl concentration groups. But, the high concentration (1,000㎍/mL) treatment of the 100mM and 200mM NaCl treatment groups was found to have a negative effect on cell survival. These results suggest that radical scavenging activity is highest in healthy plants and that they produce antioxidants to respond to NaCl salinity stress up to 100mM. However, a high NaCl concentration of 200mM has a negative effect on the physiological activity of the plants. Compared with the results of the previously reported growth index, it is thought that the growth and physiological activity of plants can be positively affected in an NaCl treatment environment of 50mM or less.