• 한국물환경학회지
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• 제26권4호
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• pp.673-680
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• 2010

Environmental factors and phytoplankton community in Lake Doam were monthly investigated at 3 stations from April 2009 to November 2009. During the study period, the concentrated rainfalls occurred at between July and August and then the TP and turbidity were sharply increased in in-lake. A total of 91 phytoplankton species was classified and these were consisted of 38 Bacillariophyceae, 35 Chlorophyceae, 10 Cyanophyceae, and 8 other species. Bacillariophyceae and Chlorophyceae were dominated during the seasonal succession of phytoplankton community, especially summer season. Bacillariophyceae was dominated from spring season to summer season and Chlorophyceae was dominated at summer season and autumn season. However, the dominance of Cyanophyceae generally developed at summer season in eutrophic water was not observed. From the analysis of correlation coefficient between environmental factors and phytoplankton cell number, we confirmed that there was a negative correlation between turbidity and cyanobacteria cell number (P<0.01). This result indicated that turbid water acts as the inhibitor of the cyanobacteria growth than other phytoplankton community.

• Fisheries and Aquatic Sciences
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• 제5권4호
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• pp.281-286
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• 2002

Artificial reefs were set on a sandy bottom substratum at 8m, 10m and 13m depths along the coast in Muronohana, Ikata, Japan. Succession of seaweed communities was observed monthly or bimonthly from February 1999 to August 2000 on artificial reefs. Within one month, the diatom colonized on the reefs with coverage of $100\%$. After three months, Enteromorpha intestinalis and Colpomenia sinuosa dominated on the reef in the spring. Seaweed flora decreased during the summer and the dominant species were several species of Melobesioidea. In the winter, the seaweeds grew up again and the dominant species on the each reef were Sargassum spp., Ecklonia kurome and Padina arborescens after one year. The dominant species in the algal succession process changed from diatoms to the perennial seaweeds such as Sargassum spp., E. kurome and P. arborescens. Thus, the pattern of succession of the dominant species and the degree of domination were changed by the season, water depth and the recruitment of spores and eggs from the mature alga around the reefs.

• ALGAE
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• 제21권3호
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• pp.305-310
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• 2006

Succession of artificial seaweed communities in an artificial iron reef at Ikata, southern Japan was studied based on monthly or bimonthly observations from February 1999 to August 2000. Communities were associated with different substrata (40 cm x 60 cm: steel, concrete, wood and stone) as the cover on artificial iron reefs (4.5 m x 4.1 m x 2.5 m, 45.38 m3 and 3.2 ton), which were placed on a sandy substratum at 8 m depth. Within one month diatoms dominated on all substrata with cover of approximately 100%. Enteromorpha intestinalis and Colpomenia sinuosa dominated on the reef within three months after the placement in the spring. Seaweed communities on the reef decreased during the summer. In the winter, the seaweeds on the reef recovered. Sargassum spp., Ecklonia kurome and Padina arborescens dominated on each substratum after one year. Seaweed communities on the artificial reef were similar to those on the rocky substratum around the artificial reef and also similar on different substrata covering the iron artificial reef. These results indicate that seaweed succession was impacted by season and the recruitment of spores and propagules from mature algae around the artificial reefs.

• The Korean Journal of Ecology
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• 제23권4호
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• pp.299-307
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• 2000

To understand the mechanism of phytoplankton succession in the Nakdong River, the resource availability (silica) and grazing effect on the phytoplankton community were investigated in an enclosure experiment at Mulgum in March 1995. In all enclosures, Stephanodiscus hantzchii was dominant during the first week. Two weeks later, the diatom community in the A (river water only) and B (filtered river water) enclosures was shifted to colonial green algae (Actinastrum sp., Pediastrum spp. and Scenedesmus spp.) and nanoplankton (2~3 ${\mu}$m of diameter) due to the silica depletion. In the C (silica addition in river water, 3 mg 1$^{-1}$ week$^{-1}$) and D (silica addition in filtered water) enclosures, Fragilaria crotonensis and Synedra acus increased as the silica addition was continued. The percentage of small phytoplankton (size, 10~13 ${\mu}$m) in the filtered enclosures (B and D) was much higher than that of A and C enclosures. A laboratory bottle experiment conducted in the fall of 1994 also showed similar results. Therefore, it is concluded that silica and zooplankton are important regulators in phytoplankton succession during the diatom blooming season in the Nakdong River.

• 생명과학회지
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• 제18권10호
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• pp.1400-1409
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• 2008

본 연구는 집돼지 사체주위에서 채집되는 곤충의 천이패턴을 이용해서 사체의 사후경과시간을 추정하기 위한, 법의학적 증거모델을 제시하고자 수행되었다. 사체의 주변에서 총 7목28과 48종의 곤충이 채집되었는데, 계절에 따라 많이 나타나는 곤충이 변하여 3월, 5월 및 10월에는 검정파리과가, 7월에는 검정파리과와 반날개과가 같은 비율로, 9월에는 반날개과가 많이 관찰되었다. 검정파리과 곤충은 모든 실험을 통해서 사체에 가장 먼저 도착하는 곤충이며 또한, 부패초기의 지표곤충임이 밝혀졌다. 그러나 부패후기의 지표곤충은 3월을 제외한 나머지 연구기간 중에는 반날개과, 3월에는 집파리과였는데, 3월에는 낮은 온도로 인해서 사체 부패 기간이 오랫동안 지속되었으므로 사체 주위에 모여든 집파리과의 개체수도 증가한 것으로 생각되었다. 이상으로부터 사체의 사후경과시간을 유추하기 위해서는 사체의 부패 정도나 사체 주변에 나타나는 곤충 뿐 아니라, 조사 지역의 기후 조건도 고려해야 할것으로 생각되었다.

• ALGAE
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• 제20권1호
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• pp.43-52
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• 2005

A study on the seasonal changes in the phytoplankton community was carried out in four aquaculture ponds of Bangladesh over a period of 16 months from August 2000 to November 2001. Out of 45 phytoplankton species identified, 30 belong to Cyanophyceae, 7 to Chlorophyceae, 5 to Bacillariophyceae and 3 to Euglenophyceae. The highest phytoplankton abundance was observed in spring followed by early autumn, summer, and the lowest was in winter. The annual succession of Cyanophyceae was characterized by spring and early autumn period dominated by Microcystis sp. Anabaena sp. and Planktolymbya sp. with Microcystis sp. as the main blue-green algae represented. Chlorophyceae was characterized by rainy season domination of Chlorella vulgaris, Pediastrum sp. and Scenedesmus denticulatus with maximum abundance of Chlorella vulgaris. Whereas Bacillariophyceae was dominant during the winter period. Navicula angusta and Cyclotella meneghiniana were the most frequently occurring species of Bacillariophyceae throughout the study period. Euglenophyceae was dominant in late autumn and Euglena sp. was the dominant species. The effect of various physicochemical water quality parameters on the seasonal distribution and succession of the above mentioned phytoplankton population as well as the interaction and eutrophication are discussed.

• 한국체육학회지인문사회과학편
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• 제54권4호
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• pp.329-345
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• 2015

본 연구는 한국프로축구팀 감독교체가 팀 경기성과에 미치는 효과를 경영학의 조직학습이론을 적용하여 규명하고자 하였다. 1983년 시즌부터 2013년 시즌까지 30년 동안의 19개 팀과 96명의 감독에 대한 307개의 팀-연도 데이터를 기반으로 패널데이터를 구성하였고, 최종적으로 226개의 팀 데이터가 실증분석에 투입되었다. 자동상관 및 이분산성의 문제를 해결하기 위하여 고정효과 일반화최소자승법(Fixed Effect Generalized Least Square Regression)을 사용하여 분석하였으며 연구결과는 다음과 같다. 첫째, 감독교체는 팀 경기성과와 부(-)의 관계를 가지는 것으로 나타났다. 둘째, 시즌기간(on-season)의 감독교체는 팀 경기성과에 부정적인 영향을 미치는 것으로 나타났다. 시즌기간에 감독을 교체하는 경우 악순환이론 관점이 적용되는 것으로 확인되었다. 셋째, 비시즌기간(off-season)의 감독교체는 팀 경기성과에 긍정적인 영향을 미치는 것으로 나타났다. 비시즌기간에 지도자를 교체하는 경우 상식이론 관점이 적용되는 것으로 확인되었다. 넷째, 시즌기간의 감독교체와 비시즌기간의 감독교체 간의 팀 경기성과의 차이를 비교한 결과, 비시즌기간의 감독교체가 시즌기간의 감독교체에 비해 유의한 팀 경기성과를 보였다. 다섯째, 감독교체가 발생한 경우 후임감독으로 내부출신을 선호하는 것으로 나타났다. 여섯째, 내부출신감독은 팀 경기성과에 부정적인 영향을 미치는 것으로 나타났다. 일곱째, 감독교체와 팀 경기성과 간의 부(-)의 관계 사이에는 내부출신감독요인이 매개 역할을 하는 것으로 나타났다. 본 연구는 프로축구산업 현장에서 팀 경기성과의 향상을 위한 감독교체가 필요할 때 후임 감독이 역량을 효과적으로 발휘할 수 있는 교체시기에 대한 시사점을 제공한다.

• Ocean and Polar Research
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• 제32권2호
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• pp.97-111
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• 2010

Phytoplankton production is affected by various physico-chemical factors of environment. However, one of the most critical factors generally accepted as controlling primary production of phytoplankton is nutrients. It has recently been found that the succession of phytoplankton groups and species are closely related to the chemical properties of ambient water including nutrient limitation and their ratios. In Jangmok Bay, silicate and nitrate are primarily supplied by rainfall, while phosphate and ammonia are supplied by wind stress. Typhoons are associated with rainfall and strong wind stress, and when typhoons pass through the South Sea, such events may induce phytoplankton blooms. When nutrients were supplied by heavy rainfalls during the rainy season and by summer typhoons in Jangmok Bay, the dominant taxa among the phytoplankton groups were found to change successively with time. The dominant taxon was changed from diatoms to flagellates immediately after the episodic seasonal events, but returned to diatoms within 3~10 days. Pseudo-nitzschia spp. were dominant mainly in the presence of low phosphate levels during the first of the survey which included the rainy season, while Skeletonema costatum was dominant when phosphate concentrations were high due to the strong wind stress during the latter half of the survey as a result of the typhoon. The competition between S. costatum and Chaetoceros spp. appeared to be regulated by the silicate concentration. S. costatum preferred high silicate and phosphate concentrations; however, Chaetoceros spp. were able to endure low silicate concentrations. These results implied that, in coastal ecosystems, the input patterns of each nutrient supplied by rainfall and/or wind stress appeared to contribute to the summer succession of phytoplankton groups and species.

• 한국환경복원기술학회지
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• 제9권1호
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• pp.41-54
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• 2006

In case of leaving artificial slopes resulting from large-scale constructions, there may be secondary damage caused by soil loss due to erosion and collapse. Furthermore, slope-restoring constructions have a few problems such as monotonous landscape and difficult succession of secondary vegetation due to reckless use of exotic grass, despite attaining the initial purpose of revegetation. To settle this problem, selected plants deemed to be proper for revegetation were used on one of thin vegetation base methods, CODRA SYSTEM, and made seeding mixture experimental plots considering germination rates differing in each season. Native herbs, native shrubs and exotic herbs contents were increased by 30% and 50% respectively, centered on seeding quantity(30g/$m^2$) used as design standard in the seed spray method, in order to figure out proper quantity for revegetation in each season.

• Ocean and Polar Research
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• 제30권4호
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• pp.419-426
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• 2008

Ciliate plankton samples were collected biweekly from July 2006 to June 2008 in Jangmok Bay of Geoje Island. Species composition and abundances were analyzed by quantitative protargol stain and environmental parameters were also examined. A total of 88 ciliate species occurred during the study period, consisting of 22 tintinnids, 51 oligotrichs, and 15 other species. Higher ciliate abundances appeared from June to October during the warm season ($<20^{\circ}C$) and the maximum ($4.0{\times}10^4\;cells\;L^1$) in August, while the lower abundances were found during the cold season. The minimun ciliate abundance was found in November when water temperature rapidly decreased. The temporal succession of dominant species was very clear and opportunistic. Pelagostrombidium sp., Tontonia simplicidens, Helicostomella subulata, and Myrionecta rubra were co-dominant in summer while Rimostrombidium orientale occurred abundantly in winter. Strombidium tressum and S. compressum, eurythermal species, were observed during all seasons. Based on the species-specific ecology of ciliate plankton, it is suggested that the indicative ciliate species can be applied as a biological tool to detect environmental change in the southern coastal waters of korea.