• Korean Journal of Microbiology
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• v.33 no.1
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• pp.66-71
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• 1997

호수 생태계내의 생물군집은 생산자로서의 식물플랑크톤과 소비자로서의 동물플랑크톤 및 어류가 주된 위치를 차지하고 세균은 분해자로서 기능한다는 것은 일반적으로 알려진 사실이다. 그러나 1970년대에 들어 세균군집이 생태계내에서 먹이사슬을 연계하는 2차 생산자로서도 기능한다는 사실이 제기되어, 오늘날에는 생태계내에서 세균군집의 역할이 보다 강조되고 있다(6,40,41,42,50). 먹이사슬에 대한 관심은 많은 연구결과들을 생산하였지만 복잡한 먹이사슬 구조는 아직까지 부분적인 이해만을 허락하고 있다. 특히, 어류, 동물 플랑크톤, 식물플랑크톤, 미생물의 각 분야가 서로 구분되어 발전해 왔기 때문에 이들간의 상호작용을 정확하게 밝히는 데에는 많은 한계가 있어 왔다. 1970년대 이래로 담수생태계의 부영양화를 해결하기 위한 방안으로서 생태계내의 먹이 사슬을 이용하는 생물조작의 개념이 대두되었으며, 각 분야의 통합적 연관성을 필요로 함으로써 생태계 이해에 많은 지식을 제공하였다. 이 글에서는 담수생태학의 한 분야로서 생물군집간의 상호작용인 먹이사슬의 연구동향을 생물조작 개념을 중심으로 기술하고자 한다.

• The Korean Journal of Malacology
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• v.7 no.1
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• pp.30-48
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• 1991

한국해역 종합 해양자원도 작성연구(남해)의 일환으로 저서생물 분포 연구를 위한 조사가 1990년 7월과 8월에 남해에 위치한 83개 조사정점에서 수행되었다. 각 정점에서 van Veen그랩으로 3회씩 채집된 저서 생물 표본 가운데 연체동물만을 선별 그들의 분포 양상을 파악하고자 종 동정과 함께 군집구조 분석을 하였다. 조사에서 채집된 연체동물은 모두 679개로 다섯개 강에 102종으로 동정되었으며, 이매패류가 출현종수(84.3%)에서나 출현개체수(92.3%)에 있어서 절대우점하였다. 전체 연체동물군집에서 우점하는 일곱 종(이매패류 여섯 종, 무판류 한 종)이 전체 출현개체수의 61.0%를 차지하였다. 남해의 연체동물은 종은 다양한 반면에 서식밀도나 생물량은 매우 빈약하였다. 출현종의 서식 유무에 따른 유사도로써 집괴분석한 결과 다섯개의 조사정점군으로 나누어지고, 이 들은 특징적인 분포 특성을 갖는 두 정점군과 혼합된 특성을 나타내는 세정점군으로 대별되었다. 전자의 두 정점군은 Raetellops Pulchella와 Periploma otohimeae로 대표되는 황해의 저층냉수의 영향을 받는 세립퇴적물 군집과 뚜렷한 대표종은 없지만 대마난류의 영향을 받는 이질성의 조립퇴넉물 군집으로 정의할 수 있었다. 대마난류의 영향을 받는 정점군의 군집은 황해저층냉수의 정점군에 비해 종 다양도는 높지만, 서식생물량은 현저히 적었다. 아울러 연체동물의 분포와 남해의 퇴적환경이나 수괴의 조성과 변화를 고려하여 남해에 서식하는 저서생물 군집에 있어서 네 개의 분포구역이 있을 것으로 추정하여 그 범위와 경계를 제안한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.11
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• pp.1119-1126
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• 2012

The collective behavior of bacteria plays an important role in biofilm development. In this study, the fluidic properties of biofilms formed in Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) colonies were compared by visualizing 200-nm fluorescent beads that were initially embedded in an agar plate and distributed spontaneously on the upper surface of the growing colonies. We conducted experiments to measure the three-dimensional profile of the E. coli colony using fluorescent microbeads that did not flow in the colony. Vortical flow patterns near the edge of the B. subtilis colony were observed clearly by tracking the movement of the beads in the biofilm of the colony. The present study should be the first step toward determining the effect of fluidic biofilms on the growth and swarming dynamics of bacteria.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.362-372
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• 2011

The relationships among total epiphytes, algal epiphytes and eelgrass ($Zostera$ $marina$ L.) were studied at eelgrass medows from July, 1998 to July, 1999 in Yulim-ri, Yeosu, Korea. Epiphytic diatoms on eelgrass leaves were observed from July to December 1998. From the results of this study, we inferred the following three (3) conclusions : 1) As eelgrass grew older, biomass of epiphytes increased, according to relationships between the leaf length and area of eelgrass and biomass (DW, AFDW and Chl. $a$) of epiphytes. 2) According to the ratio of dry weight, ash-free dry weight and Chlorophyll of epiphytes, the algae with calcareous or siliceous skeletons, such as coralline algae or diatoms, were dominated in the epitphytic algae community. 3) The autotrophic index (AI) calculated from AFDW and Chl. $a$ of epiphytes varied from 151 to 375. However, the period of autotrophic community was shorter than heterotrophic community and the value of AI was high. From these results, we inferred that heterotrophic community, including detritus or microorganisms were dominated in the most of research period.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.49-58
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• 2016

Compared to planktonic bacterial populations, biofilms have distinct bacterial community structures and play important ecological roles in various aquatic environments. Despite their ecological importance in nature, bacterial community structure and its succession during biofilm development in the Antarctic marine environment have not been elucidated. In this study, the succession of bacterial community, particularly during the early stage of biofilm development, in the Antarctic marine environment was investigated by pyrosequencing of the 16S rRNA gene. Overall bacterial distribution in biofilms differed considerably from surrounding seawater. Relative abundance of Gammaproteobacteria and Bacteroidetes which accounted for 78.9-88.3% of bacterial community changed drastically during biofilm succession. Gammaproteobacteria became more abundant with proceeding succession (75.7% on day 4) and decreased to 46.1% on day 7. The relative abundance of Bacteroidetes showed opposite trend to Gammaproteobacteria, decreasing from the early days to the intermediate days and becoming more abundant in the later days. There were striking differences in the composition of major OTUs (${\geq}1%$) among samples during the early stages of biofilm formation. Gammaproteobacterial species increased until day 4, while members of Bacteroidetes, the most dominant group on day 1, decreased until day 4 and then increased again. Interestingly, Pseudoalteromonas prydzensis was predominant, accounting for up to 67.4% of the biofilm bacterial community and indicating its important roles in the biofilm development.

• Journal of the Korean Data and Information Science Society
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• v.23 no.1
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• pp.39-51
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• 2012

Cluster analysis has proven to be a useful tool for investigating the association structure among genes and samples in a microarray data set. We applied several cluster validation measures to evaluate the performance of clustering algorithms for analyzing microarray gene expression data, including hierarchical clustering, K-means, PAM, SOM and model-based clustering. The available validation measures fall into the three general categories of internal, stability and biological. The performance of clustering algorithms is evaluated using simulated and SRBCT microarray data. Our results from simulated data show that nearly every methods have good results with same result as the number of classes in the original data. For the SRBCT data the best choice for the number of clusters is less clear than the simulated data. It appeared that PAM, SOM, model-based method showed similar results to simulated data under Silhouette with of internal measure as well as PAM and model-based method under biological measure, while model-based clustering has the best value of stability measure.

• 한국해양학회지
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• v.22 no.4
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• pp.257-270
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• 1987

Fouling communities developing in Jinhae Harbor and Masan Bay were studied by slide and panel immersion test during the period from Dec., 1982 to Nov., 1983. The total viable count of bacteria was estimated more than 1.7${\times}$ 10$\^$4/CFU/$\textrm{cm}^2$ after 15 days of immersion and 46 taxa of benthic diatoms were classified in micro-community. Progressional change of fouling communities was clearly shown and dominant diatom species are Licmophora flavellata, Navicula grevillei, and Nitzschia closterium Major macrofouling organisms are Mytilus edulis, Balanus amphitrite amphitrite, Hydroides ezoensis, and Celleporina sp. Wet weight production of macrofouling organisms exceeds 500g/100cm$\^$2/ after 5months of immersion. Regional defferences in community development are clearly shown in two study areas, and mainly due to the disparities of physicochemical stability and nutritional status of ambient water. Seasonality of larvae and the growth rate are the important factors in fouling community development. Overall process of community development is as follow : bacteria and diatoms-multicellular algae-barnacle, mussels and polychaete-sponge, anemone and ascidian.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2002.11a
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• pp.51-58
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• 2002

연안에 가까운 광양만 퇴적토를 대상으로 하여 PAHs 오염도와 말단제한절편 다형성 분석방법(T-RFLP method)을 이용하여 미생물 군집구조를 조사하였다. 조사된 10개 정점의 PAHs오염도는 80$\pm$20~5,690$\pm$580 (평균 1,499$\pm$1,716) ng/g dry wt.였으며 폐수종말처리장이 위치하는 하천 입구에 위치한 정점 (Wl)과 광양제철소 우수배출구 입구에 위치한 정점에서 상대적으로 높은 농도를 보였다. T-RFLP방법으로 조사한 미생물 군집은 10개 정점이 4개의 그룹으로 구분되었으며 정점 Wl에서 다른 정점과 다른 독특한 군집구조를 형성하였다. PAHs 농후배양시료에서의 미생물군집구조 변화와 비교해 볼 때 조사대상지역 퇴적토의 미생물 군집구조는 PAHs의 오염에 부분적으로는 영향을 받지만 입도, 유기물 등과 같은 환경요인이 군집구조를 결정하는 주된 요인인 것으로 생각된다.

• Korean Journal of Environmental Biology
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• v.17 no.3
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• pp.233-247
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• 1999

A survey of syntaxa of vegetation of evergreen broad-leaved forests in Korea, class Camellietea japonicae is presented. 399 releve's were arranged two phytosociological tables, each representing an alliance. A synoptic table comprising all alliances is presented. The vegetation of evergreen broad-leaved forests is divided into three alliances including twelve new associations: (1) Querco - Castanopsion all. nov., split into four associations, Castanopsietum sieboldii, Quercetum acutae, Quercetum myrsinaefoliae and Litseetum japonicae; (2) Machilo-Camellion all. nov., separate into ten associations, Machiletum thunbergii, Pittosporetum tobirae, Aucubetum japonicae, Neolitsetum sericeae, Euryetum emarginatae, Elaeagnetum macrophyllae, Camellietum japonicae, Theo-Camellietom japonicae, Raphiolepietum umbellatae and Daphniphylletum macropodae; (3) Dendropanaco-Castanopsion sieboldii including one association, Hosto minoris-Castanopsietum sieboldii. The alliances are floristically and ecologically characterized and their distribution in Korea shown on the map.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.2
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• pp.212-219
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• 2019

This study was conducted to investigate marine algal community characteristics and the status of barren ground in the summer at study sites on Jeju Island, Korea. Sampling was carried out from July to September 2017 using a qualitative and quantitative survey (including coverage of non-geniculated coralline algae and density of grazer) by scuba diving. A total of 121 species were identified, including 11 (9.1 %) green algae, 24 (19.8 %) brown algae, and 86 (71.1 %) red algae. Hyeongjeseom had the greatest diversity, with 60 species, and Harye the least, with 18 species. The mean biomass at the study sites was $1,503.0g{\cdot}m^{-2}$, while the mean for the neighboring islets ($3,268.7g{\cdot}m^{-2}$) was higher than that of the main island ($914.7g{\cdot}m^{-2}$). Also, dominant species was identified: Sargassum macrocarpum at the neighboring islets, and Ecklonia cava at the main island, with differences showing not only in biomass but also species composition. In conclusion, the marine algal community status in summer at the study sites was evaluated based on the algal community characteristics (species composition, biomass, biomass ratio of kelp species), coverage of non-geniculated coralline algae, and density of grazer. As a result, both Hyeongjeseom and Marado require preservation and management to maintain their excellent marine algal communities, and other sites on the main island require the creation and/or restoration of marine algal communities. In addition, as the generation of barren ground accelerates, it is urgent not only to grasp existing monitoring research but also to identify the status of the marine algal community where it is not known at present.