• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.503-509
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• 2010

The seasonal and interannual variation in the species composition and abundance of the decapod assemblage (shrimps, crabs, and hermit crabs) collected using pots in the coastal waters off Gori were studied between 2005 and 2008. During the study period, 49 decapod species belonging to 19 families were collected. The dominant species were Crangon hakodatei, Pandalus gracilis, Carcinoplax longimana, Charybdis bimaculata, Carcinoplax vestita, Diogenes edwardsii, and Dardanus arrosor. These seven species accounted for 95.46% of the total number of individuals collected. The number of species, number of individuals, biomass, and species diversity indices fluctuated with the seasons. The peak number and biomass of individuals occurred in July 2006. The number and biomass of individuals were higher in summer and lower in winter, and the diversity indices were lower in summer than in the other seasons. The abundance of dominant species showed some seasonal and interannual change; in particular, those of C. hakodatei and P. gracilis corresponded with the bottom water temperature.

• Animal cells and systems
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• v.5 no.2
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• pp.117-126
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• 2001

Occurence, seasonal changes and vertical distribution of the silica-scaled chrysophytes in a small fish-free pond were studied using electron microscopy (EM) and light microscopy (LM) from October 1998 to July 1999. The phytoplankton community was characterized by Chrysophyta and Cryptophyta. Ten species of the silica-scaled chrysophytes of genera Mallomonas, Synura, Chrysosphaerella and Spiniferomonas were identified by EM, and the most abundant species were Mallomonas akrokomos and M. portae-ferreae. The maximum population density of M. akrokomos was observed in December and several peaks appeared periodically at about one to two month intervals, whereas M. portae-ferreae developed the maximum density in March. The diurnal vertical distribution of M. akrokomos exhibited clear downward migration at night and slightly upward migration in the morning. A complex interaction among physico-chemical and biological factors seemed to affect the vertical distribution of M. akrokomos. However, the seasonal changes of M. akrokomos did not show significant corre1ations with the physico-chemical and some biologica1 factors. Although M. akrokomos was evenly distributed throughout the water column during some experimental periods, the diurnal patterns found in the two diurnal cycles showed consistency in that it clearly avoided the surface water during the day. This suggested that M. akrokomos may be a shade plankton with maximum densities below surface layer.

• Journal of Species Research
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• v.10 no.1
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• pp.46-56
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• 2021

Diatoms have been used in examining water quality and environmental change in freshwater systems. Here, we analyzed molecular profiling of seasonal diatoms in the Han River, Korea, using the hypervariable region of 18S V1-V3 rRNA and pyrosequencing. Physicochemical data, such as temperature, DO, pH, and nutrients showed the typical seasonal pattern in a temperate region. In addition, cell counts and chlorophyll-a, were recorded at high levels in spring compared to other seasons, due to the diatom bloom. Metagenomic analysis showed a seasonal variation in the phytoplankton community composition, with diatoms as the most frequently detected in spring (83.8%) and winter (69.7%). Overall, diatom genera such as Stephanodiscus, Navicula, Cyclotella, and Discostella were the most frequent in the samples. However, a large number of unknown Thalassiosirales diatoms were found in spring (35.5%) and winter (36.3%). Our molecular profiling revealed a high number of diatom taxa compared to morphological observation. This is the first study of diatoms in the Han River using molecular approaches, providing a valuable reference for future study on diatoms-basis environmental molecular monitoring and ecology.

• Journal of Environmental Science International
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• v.23 no.9
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• pp.1563-1572
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• 2014

The autecology of the Zostera marina and Z. japonica was studied in populations growing in the same locality (Sagumi Bay, southwestern coast of Korea). Environmental factors and plant characteristics were examined monthly from August 2008 to September 2011. Along intertidal zone, Z. japonica (0.1-0.5 m above mean lower low water, MLLW) occurred above Z. marina (0.5-2.5 m MLLW). Tidal exposure at low tide during day was the highest in the spring and the lowest in the summer. Underwater Irradiance showed seasonal fluctuation that was the highest in spring and summer caused by tidal pattern. Strong seasonal patterns in water temperature appeared to control the seasonal variations in morphology, biomass and leaf growth. The seasonal pattern of Z. japonica resembled that of the Z. marina in morphological characteristics, above-and below-ground biomass, whereas it differed in shoot density and leaf elongation. Despite some similarities in seasonal growth patterns, the patterns of Z. japonica were lagged by 2 month of Z. marina. Seasonal variation in the above biomass of Z. marina was caused by changes in density and plant size, whereas that of Z. japonica was mainly caused by changes in shoot density. Zostera marina was more sensitive to high temperatures than Z. japonica, and the increasing water temperature during the summer became the factor that inhibits the growth of the Z. marina. Zostera Japonica, there is no clear change according to the amount of the light. It is because its habitat locates above that of Zostera marina so that the amount of the light that is necessary to growth is enough and in this condition, any preventing factor does not seem to work at all. Although underwater light getting into Zostera marina's habitat is very low level and there is no any hindrance to the survival of them, it prevents them from their productivity a bit.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.10
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• pp.1394-1398
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• 2000

This experiment was carried out to examine the seasonal changes in feed intake and feeding behavior in Korean spotted deer under farmed condition to obtain basic information for efficient feeding management. The seasonal daily gain was the highest (p<0.05) in summer and the lowest (p<0.05) in winter. Dry matter intake (DMI) was the highest (p<0.05) in spring (2,685 g/day) and the lowest in winter (1,929 g/day). Intake of roughage in the DMI was the greatest in spring and that in winter was significantly lower (p<0.05) than in spring. Also DMI, expressed in terms of metabolic body weight ($kgW^{0.75}$), was 85.5 g, 70.6 g, 70.9 g and 65.1 g for spring, summer, autumn and winter, respectively, and thus was the highest in spring and the lowest in winter (p<0.05). Deer exhibited similar eating patterns, comparatively short and frequent periods, in all seasons. They showed comparatively intensive patterns of rumination during midnight for autumn and winter and relatively continuous patterns of chewing activity during spring and summer. There were no significant differences in seasonal eating time and ruminating time. However, exercise time was the greatest for winter and the lowest for summer and there was a significant difference (p<0.05) between summer and winter. Although not significant, eating time per 100 gDM ingested tended to be short in spring and summer and long in autumn and winter. Ruminating time per 100 gDM ingested was the shortest (p<0.05) in spring compared with in other seasons. The conclusion can be drawn that since deer have seasonal differences in feed intake and feeding habits, it is necessary to establish and develop an efficient feeding system for deer.

• Journal of Preventive Medicine and Public Health
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• v.40 no.3
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• pp.239-248
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• 2007

Objectives : This study was conducted to investigate the systematic error, such as seasonal change or inadequate food items, in a food frequency questionnaire administered to workers in a Nuclear Power Plant, Korea. Methods : We performed three repeat-tests with 28 subjects on May 13, July 8 and Dec 16, 1992. Our food frequency questionnaire (FFQ) comprised 84 foods organized into 7 food-groups, and was composed of the items of usual intake frequency (8 categories) and the amount per intake (3 or 4 categories) over the previous year. We compared the means of intake frequency and the frequency of the portion-size according to each season using Repeated Measures ANOVA and Pearson's chisquare test with Fisher's exact test. Results : We found the significant seasonal changes of several food items in intake frequency measurement. These items were typical seasonal foods such as mandarin orange, plum and green vegetables, while the single questions consisted of inadequate food items such as thick beef or similar soup and various kimchi products. Significant seasonal changes in portion-size were found in only two items: cooked rice-brown and fresh frozen fishes. Conclusions : The systematic errors observed could caused loss of validity in the FFQ. Consideration should be given for seasonal variation in FFQ survey and methodological concerns are needed to improve the quality for measuring usual diet pattern.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.3
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• pp.483-494
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• 1999

This study investigated the relation between seasonal variation of clothing weight and its resting metabolic rate to determine the relation between proper living temperature and cold/heat tolerance. Thirty six subjects(18 males and females twenties) were composed to obtain the clothing weight(Total clothing weight) and resting metabolic rate for a year and grouped four seasons : spring (Mar-May) Summer(Jun-Aug) Fall(Sep-Nov) and Winter(Dec-Feb). The data of males and females were respectively divided into three groups by cluster analysis with clothing weight. 1. The resting metabolic rate of male(41.1kcal/m2/hr) was higher than that of female(33.2kcal/m2/hr). It is suggested there is gender difference in the resting metabolic rate(p<.001) 2. The resting metabolic rate of male and female was the highest in Winter. It is suggested there is seasonal variation in the resting metabolic rate(p<.001) 3. It was found that there was relation between clothing weight and resting metabolic rate. The difference of resting metabolic rate between Summer and Winter which is profitable to adaptation to living temperature was significant in light clothing weight in male as well as in female. 4. In comfortable sensation most subjects responded that he/she felt 'comfortable' except Winter. However the heavy clothing weight group felt 'a little uncomfortable' throughout all seasons. l In thermal sensation most subjects responded that he/she felt 'neutral' And then the heavy clothing weight group responded warmer in summer and cooler in winter than light clothing weight group. From the results it was confirmed that male and female showed seasonal variations in clothing weight and resting metabolic rate. Also the resting metabolic rate of male and female was influenced by the clothing weight. In short seasonal variation of resting metabolic rate was larger in light clothing weight group than in heavy clothing weight group. Therefore light clothing weight group is advantgeous in living temperature to improve cold/heat tolerance and it also shows that living with the light clothing weight may enhance the degree of adaptation to change of living environment

• Ocean and Polar Research
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• v.31 no.2
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• pp.219-229
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• 2009

In order to establish annual variations in the marine ecosystem of the East China Sea, suspended solids (SSs) and particulate organic carbon (POC) were extensively investigated in the northern part of the East China Sea from August 2003 to April 2008. Surface SS concentrations showed large spatial variations in spring and fall, but not in summer. Surface SS concentrations in spring were lower than those in summer and fall. In summer, SSs discharged from Changjiang were mostly deposited in the coastal areas and did not reach our study area which was located about 260 km from the river mouth. High SS concentrations were observed near the bottom, which resulted from resuspension of bottom sediments by the bottom currents. Surface POC concentrations did not exhibited large seasonal variations. Phytoplankton biomass was a main factor controlling surface POC concentrations. POC/chlorophyll ratios showed large seasonal variations, with maximum numbers in summer. POC/PON ratios were higher in summer than the Redefied ratio (6.6), while they were lower in spring and fall. In summer, higher POC/chlorophyll and POC/PON ratios were probably attributed to the high phytoplankton mortality caused by nutrient depletion in surface waters.

• Journal of the Korean Society of Marine Environment & Safety
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• v.8 no.2
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• pp.39-44
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• 2002

In order to study the change of pollution loads flowing into Mokpo harbour after the operation of Mokpo Municipal Sewage Treatment Plant (MMSTP) and to evaluate the contribution of MMSTP operation to the improvement of marine water quality of Mokpo harbour, the pollution loads flowing into Mokpo harbour from land in dry weather were surveyed and estimated on the bases of the seasonal flow rates and the seasonal water qualities of streams and effluents located around Mokpo harbour from summer, 1997 to spring, 1998 before the operation of MMSTP, and the pollution loads of the inflow and the effluent of MMSTP were also surveyed and estimated from winter, 1998 to spring, 1999 after the operation of MMSTP. The treatment rates of MMSTP were shown to be about 49% in COD, 76% in TSS, 79% in VSS, 3% in T-N, 7% in DIP, 29% in T-P and -32% in DIN. The change rates of pollution loads flowing into the inner harbour of Mokpo due to the operation of MMSTP were shown to be about 56% In COD, 78% in TSS, 84% in VSS, 45% in DIN, 22% in T-N, 34% in T-P and -14% in DIP. The contribution rates of MMSTP operation to the reduction of total pollution loads flowing into the entire Mokpo harbour were found to be about 3% in COD, 3% in 755,5% in VSS,1% in DIP, 3% in T-P and -1% in DIN.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.12-16
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• 2005

Seasonal change in cell number and biomass expressed as chlorophyll a of picophytoplankton community in surface waters was investigated in the north basin of Lake Biwa from September 2001 to November 2002. Two main peaks, in May and summer (from July to October), were observed by change of the cell density of picophytoplankton. It is considered that peak in May was due to water temperature rise and summer peak was attributed to mass-specific nutrient uptake by picophytoplankton. Horizontal distribution in cell number and biomass of picophytoplankton community in surface water of Lake Biwa was investigated at 56 stations on June 6 ${\sim}$ 7 2002. DIN and DIP concentrations were lower in the north basin than in the south basin. The cell density and chlorophyll a of picophytoplankton were distributed almost uniformly in all area. The contribution of picophytoplankton to total phytoplankton chlorophyll a was higher in the north basin than in the south basin. These results suggest that picophytoplankton is important as a primary producer in low nutrient periods and areas of Lake Biwa.