• Ocean and Polar Research
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• 제34권1호
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• pp.1-18
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• 2012

We investigated seasonal changes in the mesozooplankton community structure in November 2006 and February, May, and August 2007 at 12 stations in the semi-enclosed Muan Bay, Korea. Forty taxa were sampled, with an average abundance ranging from 1,459 to 20,078 indiv. $m^{-3}$; the highest abundance was detected in August 2007, and the lowest in February 2007. Acartia omorii, A. hudsonica, A. ohtsukai, Bestiolina coreana, Calanopia sp., Paracalanus parvus s. l., Cirripedia larvae, Decapoda larvae, and Gastropoda larvae were the most abundant taxa detected. The species diversity of the mesozooplankton was high around the inner regions in August 2007 but it was relatively low in November 2006. Non-metric multidimensional scaling (nMDS) revealed significant differences in the structure of mesozooplankton community among the seasons. Canonical correspondence analysis (CCA), performed to examine the relationships among dominant taxa, stations, and environmental variables, showed that most species of copepods were positively correlated with temperature, salinity, chlorophyll a, and COD concentration. Our results suggested that the mesozooplankton community structure observed in this study might be affected partly by the seasonal changes in environmental variables, such as the status of the sluice gates (i.e., open or closed) and the in situ production of resting eggs by major copepods.

• 환경생물
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• 제17권2호
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• pp.139-146
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• 1999

온천배수에 의한 주변 식물상의 변화를 구명하기 위하여 고창 석정온천, 전주 죽림온천, 익산 왕궁온천을 대상으로 1997년부터 1998년까지 10회에 걸쳐서 조사하였다. 계절별 온배수에 의한 주변 식물종의 출현은 외부기온이 비교적 낮은 계절에 대조구보다 실험구에서 더 많은 종이 나타났다. 피도가 높은 종은 계절에 따라 바뀌지만 대조구와 실험구에서 차이가 없었다. 온배수에 의한 식물 엽면적의 계절별 변화는 대체로 2월, 4월, 10월에는 대조구값이 오염지역 식물보다 낮았다. 이것은 온배수에 의한 온도상승이 요인으로 판단되었다. 계절별 식물의 생체량과 건중량은 외부기온이 비교적 낮은 때에는 대조구 값이 실험구 값보다 저조하였다. 온천 배수지역의 식물체내에 함유된 무기염류의 분석결과 석정온천 지역의 Cu, Zn, Ni, Pb는 대조구보다 오염지역에서 4월부터 9월까지 증가하였고 10월에는 감소하였다. 왕궁온천 지역의 식물체 내에는 Zn, Pb함량이 대조구보다 오염지역의 값이 높았다. 그래서 온배수에 의한 식물의 영향은 기온이 낮은 계절에 나타나고, 기온이 높은 계절에 식물은 회복되는 것으로 밝혀졌다.

• 한국어류학회지
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• 제21권2호
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• pp.87-92
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• 2009

논에 서식하는 미꾸라지의 등, 체측, 후두부 피부조직에 대한 조직학적 연구를 통해 계절변화에 따른 점액세포의 변화여부를 조사하였다. 계절이 변화함에 따라 표피조직의 일반적인 형태에는 변화가 없었으나 상피조직에 존재하는 점액세포의 단위면적당 개수와 크기가 유동적으로 변화하였다. 비록 점액세포의 발달정도는 겨울철에 크게 증가하고 여름철에 감소하는 경향을 보였지만, 농지경작을 위해 관개를 실시한 봄(3~4월)과 추수를 위해 물을 배수시켜 미꾸라지의 피부가 공기에 노출되었던 가을(8~9월)에 점액세포의 월별 변화율이 가장 크게 조사되었다. 또한 농지 수온이 급격하게 높았던 6월에 점액세포가 일시적으로 발달하는 모습이 관찰되었다. 계절에 따른 점액세포의 변화는 유동적인 농지환경에 대한 능동적 행동이자 피부호흡을 하기 위함으로 여겨진다.

• The Korean Journal of Physiology and Pharmacology
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• 제19권1호
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• pp.9-14
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• 2015

We investigated the sweating response during passive heating (partial submersion up to the umbilical line in $42{\pm}0.5^{\circ}C$ water, 30 min) after summer and winter seasonal acclimatization (SA). Testing was performed in July during the summer, 2011 [summer-SA; temp, $25.6{\pm}1.8^{\circ}C;$ relative humidity (RH), $82.1{\pm}8.2%$] and in January during the winter, 2012 (winter-SA; temp, $-2.7{\pm}2.9^{\circ};$ RH, $65.0{\pm}13.1%$) in Cheonan ($126^{\circ}52^{\prime}N$, 33.38'E), Republic of Korea. All experiments were carried out in an automated climatic chamber (temp, $25.0{\pm}0.5^{\circ}C$: RH, $60.0{\pm}3.0%$). Fifteen healthy men (age, $23.4{\pm}2.5$ years; height, $175.0{\pm}5.9cm;$ weight, $65.3{\pm}6.1kg$) participated in the study. Local sweat onset time was delayed during winter-SA compared to that after summer-SA (p<0.001). Local sweat volume, whole body sweat volume, and evaporative loss volume decreased significantly after winter-SA compared to those after summer-SA (p<0.001). Changes in basal metabolic rate increased significantly after winter-SA (p<0.001), and tympanic temperature and mean body temperature were significantly lower after summer-SA (p<0.05). In conclusion, central sudomotor acitivity becomes sensitive to summer-SA and blunt to winter-SA in Rebubic of Korea. These results suggest that the body adjusts its temperature by economically controlling the sweating rate but does not lower the thermal dissipation rate through a more effective evaporation scheme after summer-SA than that after winter-SA.

• 한국농림기상학회지
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• 제8권2호
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• pp.107-115
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• 2006

오염물질에 노출된 수목에서 잎의 발달 단계와 항산화 기능의 관계를 구명하기 위하여, 1월부터 6월까지 색소 함량과 항산화 활성의 변화를 조사하였다. 폐광지역과 공단지역내 수목의 스트레스에 대한 항산화 기능은 잎 발달과 함께 변화하며, 6월에 가장 높은 항산화 활성을 나타내었다. 항산화 물질 중 계절 변화와 상관을 나타내는 것은 카로테노이드, SOD 및 CAT였으나, 카로테노이드와 SOD는 정(+)의 상관을 나타냈고, CAT는 부(-)의 상관을 보였다. 또한 $H_{2}O_{2}$,를 제거하는 데 관여하는 APX와 CAT는 상호 보완적인 관계를 나타냈다. 가장 낮은 항산화 활성을 나타내는 시기는 4월이었으며, 이 시기에는 스트레스로 인해 피해 수준도 낮았다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제24권2호
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• pp.207-217
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• 2021

Purpose: This study aimed to investigate the seasonal changes in vitamin D levels in a healthy pediatric population living in mid-latitude East Asian urban areas. Methods: A pediatric population was selected from single secondary hospital visitors. Clinical data and serum vitamin D levels were collected retrospectively. Statistical analyses were performed based on the month of the blood sampling date, subject age, and vitamin D supplementation history. The data were categorized into three subgroups based on serum vitamin D levels-adequate (≥30 ng/mL), insufficient (20-29 ng/mL), and deficient (<20 ng/mL). Results: Of the 481 patients, 172 had vitamin D supplementation history. More than 70% of the total study population had inadequate vitamin D levels (<30 ng/mL). The non-supplemented group and the supplemented group showed significantly uneven monthly distribution of the adequate, insufficient, and deficient subgroups. Only the non-supplemented group showed significantly different average vitamin D levels in the summer months compared to the winter months. In the non-supplemented group, vitamin D levels were the lowest in March, the highest in August and September. Significant relevance was noted between vitamin D supplementation status and vitamin D serum level in February and March. There was no significant difference between different age groups in terms of the distribution of vitamin D levels. Conclusion: Currently-widespread vitamin D replacement methods seem to have some effect on increasing the overall serum vitamin D levels, specifically during late winter when natural serum vitamin D levels plunge. However, they are unable to fully compensate the seasonal fluctuation.

• Fisheries and Aquatic Sciences
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• 제24권4호
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• pp.171-179
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• 2021

To better understand the ecological functioning of the coastal ecosystem in Gamak Bay on the southern coast of Korea, seasonal changes in the density, biomass, and secondary production of the copepod community were investigated. Environmental measurements (temperature, salinity, and chlorophyll a) and copepod sampling were performed seasonally from January to December 2006. The mean density of copepods (excluding nauplii) varied from 949 to 5,999 ind · m^-3; copepod density was at its highest from March to July. The copepod community comprised 32 taxa, including Calanoida, Cyclopoida, and Harpacticoida. The predominant species were Paracalanus parvus s. l., Acartia omorii, Eurytemora pacifica, Oithona similis, A. erythraea, Centropages abdominalis, Pseudodiaptomus marinus, and Calanus sinicus. There were significant spatial and seasonal variations in copepod total biomass, which ranged from 0.33 to 43.10 mg C m^-3. Mean secondary production of the copepods in Gamak Bay, estimated as 2.05 ± 1.63 mg C m^-3 d^-1 using the Huntley and Lopez growth model, was over 2 times higher than the value given by application of the Hirst and Bunker model (1.09 ± 0.85 mg C m^-3 d^-1). The daily production rate to biomass (P/B) ratio varied between 0.08 and 0.86 d^-1 (Huntley and Lopez model), and 0.18 and 0.33 d^-1 (Hirst and Bunker model). Our results emphasize the ecological significance of using models to estimate the secondary production of copepods and provides the first report of copepod production in Gamak Bay.

• 한국수산과학회지
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• 제2권1호
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• pp.16-24
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• 1969

1. 1966년 8월부터 1967년 7월까지 수영만에서 월 $1\~3$회 표층 채수 채집법으로 규조류의 계절적인 량 및 조성의 변화를 조사하였다. 2. 표층수온은 8월에 최고 $25.5^{\circ}C$이며 1월에 최저 $10.9^{\circ}C$였다. 3. 표층 염분농도는 2,3월에 최고 $34.56\%_{\circ}$이며 9월에 최저 $31.42\%_{\circ}$였다. 4. 규조류의 계절적인 조성변화중 총 45속123종 검색되었다. 5. 이 조사에서 4월에 2,551,400/l 최고량과 12월에 20,400/l으로 최소량이 나타났다. 6. 이 조사에서 가장 많은 양을 차지하는 속은 Chaetoceres, Skeletonema 양속이며 그자 Asterionella, Eucampia, Leptocylindrus, Nitrschia 등이 있다.

• The Korean Journal of Ecology
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• 제14권4호
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• pp.415-433
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• 1991

Seasonal variation in size and number of floral structures was examined in two massachusetts populations of chelidonium major, a self-compatible herb. All floral charcters except for anther number per flower declind significantly during a 3 week period. However, temporal patterns were not identical among characters or between popolations. The result indicate that floral characters varied in conjunction with flower diameter,but that the pattern of changes in floral characters in response to environments may not be easy to predict. Principal components analysis was conducted to environments may not be easy to predict. principal compenents analysis was conducted tl identify the functional relationship among floral male function, and female function, respectively, perhaps reflecting the functional distinction of floral characters. Based on this pattern, the relative allocation to sexual structures within flowers was examined: male allocation was relatively greater than female allocation eary or in the middle of flowering season, depending upon populations. Temporalvariation in relative allocation within flowers was not independent of seed tield components:; different combinations of the size and number of floral characters were correlated with different seed yield components, for example, either seed size or number per fruit, during a season. in particular, allocations to attractive and male structures were highly correlated with mean seed weight only earlier in the season. These result provide some evidence that flowering phenolgy is an important comportant to be considered in the study of sexual allocation.

• The Korean Journal of Ecology
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• 제21권3호
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• pp.187-193
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• 1998

Seasonal changes of nitrogen fixation and growth characteristics of Melilotus suaveolens population under different light conditions were quantitatively analyzed during growting period. Height growth of M. suaveolens population was promoted after April and the shade (site 2) showed 10-20% increase of height growth in compared with that of sunny (site 1). Seasonal changes of biomass were in creased after March, the biomass at site 1 attained 78.5% that of site 2 in May. Chlorophyll content was maintained high value from March to April but, Chlorophyll content of leaf at site 1 was decreased 11.7% compared to that of site 2 in May. The nitrogen content of each organ of M. suaveolens showed higher value in March and then decreased, the high nitrogen contents of reproductive organ were achieved at the flowering stage at site 1. The root nodule of M. suaveolens population appeared in March and showed maximum value in early June and decreased remarkably after July, the amount of nodule formation of M. suaveolens at site 2 showed higher than that of site 1. The nitrogen fixation activity of root nodule of M. suaveolens initiated with shoot growth and showed maximum value in mid April, and attained second peak in early June and then decreased after July. The total nitrogen fixation of the plant showed higher value at site 2 than that of site 1. From the overall results, M. suaveolens showed increased growth under half-shady, well ventilated barren soil than fertile sunny site.