• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.70-77
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• 2003

From March 1998 to August 2000, the phenological and morphometric changes of Zostera marina L. were examined at the Duksan Port in the eastern coast of Korea. Morphometric characteristics, phenological stage, shoot density, biomass of Z. marina population and environmental parameters were also measured. Nutrient levels in water column varied over the season. Morphometric characteristics of vegetative shoot changed with season; shoot heights ranged from 54.2 cm (March) to 100.0 cm (October). Reproductive shoots appeared from mid-March to early September of which the height was ranged from 97.8 cm (March) to 213.0 cm (July). The flowering phase started at 12$^{\circ}C$ and the fruit development was resulted up to 21$^{\circ}C$. The seed maturing was developed at 22$^{\circ}C$-$25^{\circ}C$. Shoot density and biomass in permanent quadrate (0.25 m$^2$) were significantly different among seasons ranging from 38 to 136 shoots (mean 80.3$\pm$6.5) for shoot density, and 190 g dry wt m$^{-2}$ in October 1998 to 922 g dry wt m$^{-2}$ in June 1998 for biomass respectively. Relationships between shoot morphometrics and physico-chemical parameters were not significantly correlated. Seasonal changes in water temperature seemed responsible for the replacement of reproductive phases and the annual changes of shoot morphometrics in Z. marina populations.

• Korean Journal of Environmental Biology
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• v.24 no.4
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• pp.392-407
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• 2006

This study was seasonally undertaken to investigate the benthic polychaetous community along the South-eastern coast of Geoje Is., in February 2004 to November. The macrobenthic fauna showed mean density of 953 md. $m^{-2}$ in February, 1,193 ind. $m^{-2}$ in May, 1,130 ind. $m^{-2}$ in September and 991 ind. $m^{-2}$ in November. Major faunal groups are polychaetes, crustaceans and mollusks, corresponding to 81.6%, 7.9%, 7.0% in total mean density during the sampling seasons, respectively. There was significant difference (two-way ANOVA, p<0.001) among stations in densities of polychaetes. But no significant relationship could be found between the densities of polychaetes and sampling seasons (two-way ANOVA, p>0.05). The density and the species number of polychaetes were high in the coastal area near the Jisepo port, independent of sampling seasons. Several indicator species for the organically enriched environments such as Lumbrineris longifolia, Tharyx sp., Heteromastus filiformis showed high densities during all study periods. Also Magelona japonica included in Ecolgical group I was the most abundant in the whole study period except for February. Cluster analysis on the basis of the species composition showed that the study area could be divided into 3 regions. The density of benthic polychaetes in the coastal area near Jisepo was higher than that in the other assemblages of the study area, due to some predominant opportunistic species, such as Lumbrineris longifolia, Tharyx sp. and Heteromastus filiformis. In addition, the two-way ANOVA showed significant differences among the distribution of AMBI (AZTI's Marine Biotic Index) values, both in sampling stations (p<0.001) and seasons (p<0.01). According to the classification proposed by Borja et at. (2000), the study area was slightly disturbed site.

• Journal of Animal Environmental Science
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• v.15 no.3
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• pp.225-230
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• 2009

The purpose of this study was to determine the effect of re-establish the amount and major pollution source of swine wastewater from swine farms. The results obtained in this study was summarized as follow; The quantity of wastewater produced from the average volume of swine wastewater was $2.49{\ell}$/head/day and $2.49{\ell}$ in spring, $2.65{\ell}$ in summer, $2.47{\ell}$ in autumn, and $2.35{\ell}$ in winter. The quantity of wastewater production during summer season was higher than of the other seasons. The water pollutant concentration in wastewater of swine farms, $BOD_5$, SS, T-N and T-P, was $4,689\;mg/{\ell}$, $2,122\;mg/{\ell}$, $3,238\;mg/{\ell}$ and $118\;mg/{\ell}$, respectively.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.372-389
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• 2008

In this study, we formed a detailed grid at the estuary area of the Nakdong and collected the surface sediments. Particle size analysis and comparison with existing data were conducted to investigate the characteristics of seasonal and long-term changes in the sediments. As a result of investigation, the distribution of the sediments showed a great change per season and was greatly influenced by the quantity of outfall discharge at the Nakdong estuary barrier and the incident wave climate. The sandy sediments showed dominant movement toward the front of Jinwoodo west of the estuary area of the Nakdong due to the influence of the ENE wave, the annually-dominant wave. And the muddy sediments showed deposition by being moved toward the deep open sea along with a current. The present conditions of the sediments at the estuary area of the Nakdong showed great differences from the results of previous studies.

• Korean Journal of Ichthyology
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• v.5 no.2
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• pp.194-207
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• 1993

This paper deals with seasonal fluctuation of fish communities around the coast of Kunsan, Korea from 1992 to 1993. A total of 98 fish species with 82 genera, 47 families, and 14 orders were collected during the study. Among fishes caught by trawl net, Cynoglossus joyneri and Repomucenus ornatipinnis predominated throughout the year, and by long back net Harengula zunasi and Engraulis japonica except winter season. There is a difference between biomass caught by long back net and by trawl net, the former showing a peak in summer and the latter showing peaks in late spring and winter. This result appears to be due to the occurrences of Platycephalus indicus and Liparis tanakai for the spawning in investigated areas. Among the 14 species collected in the intertidal zone, 13 species of the family Gobiidae were mostly found in the spawning season. These results may suggest that the coastal area of Kunsan provides a good spawning ground for the coastal fishes. It is considered that the seasonal fluctuation of the abundance and species composition in fishes in this area is mainly affected by the water temperature and the bottom habitats.

• The Journal of the Acoustical Society of Korea
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• v.21 no.3
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• pp.213-220
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• 2002

The sound wave in the sea propagates under the effect of water depth, sound velocity structure, sea surface and bottom roughness, and bottom sediment distribution. In particular the sound velocity structure in shallow water varies with time and space, an? the sediment distributes very variedly with place. In order to investigate the seasonal variation of low-frequency sound propagation in the Yellow Sea, the propagation experiments were conducted along the same track in the middle part of the Yellow Sea at various seasons of spring. summer, and autumn. In this paper we consider the measurement results on the propagation loss with the sound velocity structure, and investigate the seasonal variation of the propagation loss. As a result, the propagation losses measured in summer were larger than the losses in spring and autumn. And the propagation losses measured in autumn were smaller than the losses in spring. The seasonal change of the propagation loss increased with the rise of sound frequency and the propagation range.

• Journal of Korean Society of Forest Science
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• v.88 no.4
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• pp.562-567
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• 1999

Dendropanax morbifera Lev. leaves were collected during different seasons to analyze the chemical components. In proximate composition the leaves collected in spring had the highest moisture content and in winter had the lowest. Lipid, ash and fiber contents gradually increased from spring to winter and in winter had the highest. Protein content decreased until summer and then it increased. All of free sugars detected have gradually increased during the growing season. Unsaturated fatty acids content was higher than that of the saturated fatty acids and the major saturated and unsaturated fatty acids were arachidic acid and cis-13,16-docosadienoic acid. respectively. Fifteen free amino acids detected with arginine content being the highest regardless of season and amino acid content gradually decreased during the seasons. The highest content of mineral elements was potassium in leaves collected in spring, with calcium was the highest in leaves picked in other seasons. Vitamin C content was gradually decreased over the growing season and soluble tannin content increased notably.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.2
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• pp.178-195
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• 1999

The species composition and seasonal variation in abundance of fishes in the Nakdong River estuary were investigated monthly from February 1987 to January 1988. During the study period, 23,008 specimens belonging to 100 species were collected. The most abundant fish species were Repomucenus valenciennei, Pholis fangi, Leiognathus nuchalis, Trachurus japonicus, and Sardinella zunasi. These five species comprised 63.0% of total fishes and 47.8% of total biomass collected. The seasonal dominant fish species were P. fangi and R. valenciennei in spring, R. valenciennei and Cynoglossus joyneri in summer, Thryssa kammalensis and Apogon lineatus in fall, and R. valenciennei, L. nuchalis and S. zunasi in winter. The number of fish species, number of individuals collected, and species diversity indices fluctuated with the seasons. The number of species and number of individuals decreased significantly in the upper estuary. While temperature was an important factor which influenced on seasonal fluctuation of the fish community, salinity determined the spatial distribution of fishes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.7
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• pp.932-937
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• 2007

Quality evaluation and hazard management of lettuce (Lactuca sativa L.) which was prepared within the harvesting seasons were analyzed. Eatable weight was highest in the summer (953.40 g)>spring (912.27 g)>fall (895.28 g) lettuce, but sugar content showed the highest concentration in the spring. Total color of summer lettuce was the brightest in comparison with other seasons. Fall lettuce's color increased in yellowness more than greenness. Minerals of lettuce were abundant in the following order of K>Ca>Na>Mg>Fe in all seasons. Chlorophyll content, showing the similar trend to vitamin C, was the lowest in summer. Among the 48 different pesticides tested, only chlorthalonil was detected in a minute content from fall lettuce. In conclusion, summer lettuce was inferior to spring and fall in quality because of hot weather.

• Journal of the Korean earth science society
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• v.24 no.3
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• pp.160-171
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• 2003

This study was designed to analyze the types of concepts about earth science related to seasonal changes, so as to develop a generative learning model focused on dissolving cognitive conflicts between the aforementioned concepts through debates and using said debates to find out how effectively the model works. There are 100 types of earth science concepts concering seasonal changes, 66 of which are unscientific in nature, including misconceptions. Through a second field trial and a research and development (R&D) process, a test on these concepts was developed, consisting of 14 items. For the experimental group, a four-phase generative learning strategy that reflects the types of earth science concepts and cognitive conflicts between such concepts was developed through pre-analysis and discussion, respectively. On the other hand, a traditional teaching and teaming strategy was used for the control group. A meaningful statistic gap found between the two groups through a covariance analysis, the significance level of which was 0.05. This result may be interpreted to mean that the generative teaming strategy is a possible alternative for correcting misconceptions about scientific concepts of seasonal changes.