• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.437-450
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• 2010

Ecological influences of indigenous freshwater bivalve Unio douglasiae on the water quality and epilithic diatom community was examined with artificial stream (AST), which constructed in a laboratory daily receiving the eutrophic lake water. For the colonization of new periphyton community, forty commercial slide glasses were deposited as a substrate into the lowest part of each AST. Prior to 1 week, the AST was operated to induce the freely-colonization of the algal community in the absence of mussels. After the mussels was introduced at 435 indiv. $m^{-2}$ between step 1 and step 5, the passed water and substrates were daily collected to analysis the change of water quality and lotic and lentic algae abundance for 10 days. Compared to the control, turbidity (60.0% of control), suspended solids (62.5%), and chlorophyll-$\alpha$ (72.2%) in mussel-passed waters were decreased significantly, while a strong increase of ammonia (up to 800% of control) was companied with the decrease of dissolved oxygen (19.5% of control) and total phosphorus (23.9%), respectively. On average, the concentrations of suspended solids (67.0% of control) and chlorophyll-$\alpha$ (89.4%) in mussel-treated substrates were remarkably increased, however algal abundance in its water simultaneously decreased. These results indicate that incidentally or purposely mussel introductions can decrease organic matter of the stream and increase transparency of stream water, however, mussel-mediated nutrient and pseudofeces release may stimulate the adverse growth of periphyton or phytoplankton community in the lower stream or reservoir.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.1
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• pp.25-33
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• 1998

Temporal and spatial variations of nutrient elements (ammonia, nitrate, nitrite, phosphate and silicate) in surface seawater off the west coast of Korea were investigated during three periods of field survey aboard R/V Eardo of KORDI (May 1995 and June 1996) and a patrol vessel of the National Maritime Police (November 1995). In general, the concentrations of nutrient elements were lowest in June and highest in November except for ammonia that showed the lowest concentration in May and the highest in November. The results tell us that the development of thermocline and tidal front restricts riverine and benthic supply of nutrient elements to surface waters in June in the offshore regions of the study area which become nutrient-depleted due to phytoplankton bloom in spring. In late fall (November) the level of nutrient concentrations of the surface waters of the study area become high due to vigorous vertical mixing within the water column, which supplies nutrient-enriched bottom water to the surface waters.

• Journal of Marine Life Science
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• v.4 no.2
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• pp.86-90
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• 2019

This study aimed to compare the disinfection efficiencies of the ultraviolet and plasma systems, the two systems designed and commercialized to disinfect water in aquaculture, by putting each in a 100 ℓ water tank and concentrating 1.0 ℓ of treated water to check the changes in the number of bacteria in the samples. Each system was operated for 6 hours to culture the typical seawater bacteria in the Marine agar, Thiosulfate citrate bile salts sucrose agar and Salmonella Shigella agar media, respectively, to check the number of bacteria in the media, and the changes in the number of Edwardsiella piscicida in the treated water were checked after the artificial inoculation of E. piscicida in the disinfected seawater. As a result, the two disinfection systems showed the almost similar levels of bacterial reduction efficiency between 99.5% and 99.9%. However, the result of this study showed that, with 100 ℓ of water treated for the same length of time using the two systems, the plasma system turned out to disinfect bacteria in a shorter period of time than the UV system. However, as the changes in the number of bacteria were checked for a short length of time (6 hours) in this study, it was judged that, considering the actual aquaculture environment in which the quality of water significantly changes with feed residues, excretions and coastal contamination, etc., and a lot of biofilms and organic matter exist, the plasma system would be more efficient than the UV system as the former is capable of continuously maintaining a certain level of efficiency than the latter that is limited in terms of efficiency depending on the level of turbidity and the existence of organic matter.

• Food Science and Industry
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• v.55 no.2
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• pp.154-165
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• 2022

Humans have been breeding the mulberry silkworm for the long period of time to obtain silk fabric and nutrient-rich pupae. Currently, silkworm larvae, pupae, and silk-Fibroin hydrolysates are registered as food raw materials, while silkworm feces and Bombyx batryticatus are registered as Korean traditional medicines. Among sericulture products, individually recognized health functional food ingredients include silk-protein acid-hydrolysates for immunity enhancement, Fibroin-hydrolysates for memory improvement, and freeze-dried 5^th instar and 3^rd-day-silkworm powder for lowering-blood sugar. Recently, HongJam produced by steaming and freeze-drying mature silkworms were reported to have various health-promoting effects such as preventing the onset of Alzheimer's disease and Parkinson's disease, enhancing gastro-intestinal functions, improving skin-whitening and hair growth, and extending healthspan. By consuming silkworm products with various health-promoting effects, it is possible to increase the healthspan of human beings, thereby reducing personal and national medical expenses, resulting in increasing the individual's happiness.

• Journal of Ecology and Environment
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• v.29 no.6
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• pp.511-520
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• 2006

The study analyzed the distribution of mammalia per altitude in Gamebong, the highest trail of Juwangsan National Park and confirmed the inhabitation of 22 different species inhabiting in the park. Starting from 200 m to 800 m above the sea level was segmented into 100 m unit. The result of analysis has shown that the Tamias sibiricus is the dominant specie throughout in all segments. Species confirmed to be inhabiting in all segments of research areas were Mustela sibirica, Caproelus pygargus and squirrel. By analyzing the confirmed Field Sign basing from the observation point, it has shown close relations between types of species and population following the increase in altitude (y=-0.0234 + 25.552, $R^2$=0.9296, $F_{0.05}$(1,4)=7.71, p<0.05). However, the result of analysis targeting nine species inhabiting in at least five out of six 100 m segmented units has shown that only two species, Apodemus sgrarius (y=-0.034X+25.2, $R^2$=0.905, $F_{0.05}$(1, 4)=38.169, p<.0.01) and Sciurus vulgaris (y=-0.0154X+ 12.819, $R^2$=0.781, $F_{0.05}$(1, 4)=14.270, p<0.05) were affected by the altitude. Therefore, it is judged that the distribution of species does not follow the altitude variation but follows the food conditions and the structure of habitat. The result of analysis of Box and Whisker Diagram had shown lowest quartile deviation($Q_U-Q_L$) in Nature Restoration Area that is located in $200{\sim}300m$ above the sea level, where hikers are prohibited from entering. In $500{\sim}600m$ above the sea level segment that has similar food environment and trail, it has shown the widest distribution. Further research is required on this segment for the excretion drops of Prionailurus bengalensis, a Grade II class of endangered species, were found on the trails.

• The Korean Journal of Nuclear Medicine Technology
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• v.20 no.1
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• pp.47-51
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• 2016

Purpose By ingestion of 18F-FDG of kidney of PET/CT during the inspection, if additional examination is required, depending on whether you want to water intake, we want to confirm a change in the rate of decrease of F-18 FDG of the kidney. Materials and Methods The 80 patients without kidney disease were performed PET/CT examination. Device was analyzed after setting the kidney to a three-dimensional region of interest. In patients require additional examination, and inspection after 30 minutes, a PET/CT torso examination after the water of the 500 cc ingested at a time. After the addition of both water intake group and no hydration group of kidney of SUV, it was compared with PET/CT torso scan. Results High and low of the kidney SUV did not show a significant difference in the rate of decrease. Reduction rates of background (BKG) of additional examination was 2.8% and reduction rates of SUV was 49.7% (Hydration) : -6.8% (No hydration), so did show a significant difference. In the image blind test, the average point score of hydration and no hydration was 34.25 : 17.25. Conclusion An undercurrent of 18F-FDG in the kidney at the time of torso examination, it was confirmed that the reduction rate after the addition of water intake is high. It is considered that can be expected to improve the quality of an image due to a decrease in elongation through the kidneys examination with additional fluid intake as needed intake.

• Economic and Environmental Geology
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• v.55 no.1
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• pp.45-51
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• 2022

Whether Dokdo can sustain human habitation or economic life of their own plays an important role to the legal status of the island in the international maritime law. This study reports the hydrological survey results regarding the water resource of the island occurred at Moolgol in Seodo. The amount of underground discharge at Moolgol was estimated at least 1.1 m³/d, conforming the results of previous studies. Based on the oxygen and hydrogen isotope ratios of water, the discharge appeared to originate from precipitation, and about 36% of the daily precipitation moves fast to the Moolgol through the joints developed in the volcanic bedrocks. Quality of the discharged water shows relatively higher concentrations in Cl and NO₃ to be used for drinking and domestic purposes, probably affected by the sea spray and waves from surrounding sea and the birds' excretion such as black-tailed gulls.

• Analytical Science and Technology
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• v.28 no.6
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• pp.377-384
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• 2015

A survey of the artificial radionuclides in rivers and lakes was conducted to investigate their levels in surface water. Water samples were collected at 60 points and analyzed by gamma-ray spectrometry with a measurement time of 10,000 seconds for ¹³⁴Cs, ¹³⁷Cs, and ¹³¹I. The obained values were lower than MDA for all points, except one point for ¹³¹I that was 0.533±0.058 Bq/L. ¹³¹I is known as a radioactive material that occurs frequently in sewage treatment plants. Because it is often used for medical treatments and subject to spreading into the environment due to the excretion from the patients. For the point where ¹³¹I was detected, we conducted additional investigation on the upstream river point and the effluent points of nearby sewage treatment plant to find the source of ¹³¹I. ¹³¹I was not detected at the upstream points of one of the upstream sewage treatment plants but found at the downstream points with the level being 0.257±0.034 to 0.799±0.051 Bq/L, proving the sewage treatment plant was the ¹³¹Isource.

• Korean Journal of Organic Agriculture
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• v.15 no.4
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• pp.413-424
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• 2007

This trial was carried out to determine effects of TMR(Total Mixed Ration) in comparison to conventional diet on feed intake, digestibility, and nitrogen retention in Korean black goats. Twelve Korean black goats were allotted to treatments in four groups of three goats and the they were housed in separate metabolism cages for 21 days. Treatments included conventional diet(A: rice straw and commercial concentrates) as a control group and three TMR groups(B: rice straw and commercial TMR; C: 30% organic whole barley silage and rice straw with organic grain; D: 60% organic whole barley silage with organic grain). The results obtained are summarized as follows. Dry matter intake, fecal excreta, digestible dry matter, metabolic intake and feed intake of BW were significantly higher(p<0.05) compared with A, B, C treatment. The digestibility for most of nutrients except NFC was significantly higher(p<0.05) for D treatment than the others. On the other hand, the digestibility of NFC was higher for B treatment than for the others, even if it was not significantly different across treatments. Nitrogen intake was lower for D treatment, but the significant differences were not found across treatments. N retention rate was higher for B treatment with significant difference. For the blood composition, HDL cholesterol and Immunoglobulin G were significantly higher(p<0.05) for C, D treatment than the others. The results showed that, in comparison with A treatment(conventional diet) and B treatment(commercial TMR), dry matter intake, nutrient digestibility and N retention rate were not lower in C treatment(30% organic whole barley silage) and HDL cholesterol was increased after experiment. Therefore, it could be concluded that TMR with organic whole barley silage might contribute to the production of a high quality and safer meat in goat production.

• Journal of Environmental Impact Assessment
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• v.23 no.6
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• pp.492-504
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• 2014

Feral pigeon (Columba livia) has been known as a good indicator for accumulations of chemical pollutants in urban areas. However, it is against the animal rights to kill the indicator species in order to monitor pollutants accumulations in wild birds. Eggs and feathers of birds, therefore, have been used as non-invasive monitoring materials. Even though eggs are a good indicator for accumulations of lipophilic pollutants, but unsuitable for some heavy metals such as lead and cadmium because bird's ovary builds a sort of barrier to inhibit higher accumulations of some heavy metals in the eggs. Therefore, feathers instead of eggs have been used as a non-invasive indicator for accumulations of heavy metals. However, there are few studies of heavy metal accumulations of feral pigeon in Korea. In this study, we characterized the characteristics of heavy metal accumulations of feathers in relation to internal organs (bloods, viscera and bones) in feral pigeons between two sites (Hangang Park representing urban area and Hampyeong Park for rural area). The samples from the Hangang Park showed significantly higher lead (Pb) concentrations in the blood, liver and bone than those from Hampyeong Park. The Pb concentration in the feathers was also significantly higher at Hangang Park than at Hampyeong Park. The analytical result for the breast, wing and tail feathers, and the internal organs (blood, lung, liver, kidney and bone) indicated that the Pb concentrations in the feathers were significantly positively correlated with the levels in the kidney and bone. Overall, feathers of feral pigeon may be candidate for bioindicator to monitor for Pb accumulations in urban areas.