• 생태와환경
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• 제49권2호
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• pp.130-141
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• 2016

This study was conducted to elucidate the structure of river ecosystem in the watershed of the Seom River and Hoengseong Reservoir located in Hoengseong of Kangwon Province from February to October 2007. Topics of the survey were mainly rainfall, discharge, water quality in abiotic factors and attached algae, benthic macroinvertebrates, fish, birds and mammals of flora and fauna in a biotic factors, respectively. Specifically, the Seom River could be seen as a typical flow rate of the stream is controlled to the effect of the dam. Basic water qualities were great to seasonal effects, it was relatively clean. Diatom Achnanthes, Cymbella, Gomphonema, and Navicula were distributed predominantly in the periphytic algae. Benthic macroinvertebrates were mostly aquatic insects and freshwater shellfish, the aquatic insects were abundant Ephemeroptera and Trichoptera. Freshwater fish was the dominant Zacco platypus, fish species varied toward the downstream. Birds were mainly observed in four species, and species Egretta garzetta, which was distributed in a wide area of the Seom River. In mammals, Lutra lutra of Mustelidae was identified that the number of inhabit widely. In aspects of the ecological trophic level, the Seom River was maintained at a relatively stable state in the producer and the consumer relationship. The results of this study will expected to be utilized as a useful data for understanding the structure and function of the lotic and lentic ecosystems.

• Ocean and Polar Research
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• 제33권2호
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• pp.99-111
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• 2011

To estimate the effects of limitation nutrients for phytoplankton growth and its influences on short-term variations of a winter phytoplankton community structure, we investigated the abiotic and biotic factors of surface and bottom waters at 20 stations of inner and offshore areas from 6 to 7 February in Gwangyang Bay, Korea. Also, several algal bio-assay studies were conducted to identify any additional nutrient effects on phytoplankton assemblage using surface water for the assay. The dominant species in the bay was diatom Skeletonema costatum, which occupied more than 70% of total species in most stations (St.1-16) of the inner bay. According to a cluster and multidimensional scaling (MDS) analysis based on phytoplankton community data from each station, the bay was divided into three groups. The first group included stations from the south-western parts of Myodo lsland, which can be characterized as a semien-closed eutrophic area with high phytoplankton abundance. The second group included most stations from the north-eastern part of Myodo lsland, influenced indirectly by surface water currents from offshore of the bay. The standing phytoplankton crops were lower than those of the first group. The other cluster was restricted to samples collected from offshore of the bay. In the bay, silicon (Si) and phosphorus (P) were not a major limiting factor for phytoplankton production. However, since the DIN: DIP and DSi: DIN ratios clearly demonstrated that there were potential stoichiometric N limitations, nitrogen (N) was considered as a limiting factor. Based on the algal bio-assay, in vivo fluorescence values in N (+) added experiments were higher compared to control and P added experiments. Our results suggested that nitrogen may act as one of the most important factors in controlling primary production during winter in Gwangyang Bay.

• 미생물학회지
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• 제36권4호
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• pp.285-291
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• 2000

강진만 수역에서 이화학적 요인과 미생물군집의 변화를 조사하기 위해 영양염류, 수온, 투명도, 염분도, DO, COD 및 종속영양세균, 균류 그리고 분변성 대장균을 계절별로 분석하였다. 분석 결과 조사기간 동안 분변성 대장균군과 종속영양세균의 개체수 변화는 각각 16.1~166.0 CFU/ml 과 $5.0{\times}10^3$~$13.1{\times}10^3$CFU/ml의 범위를 보였다. 또한 이들 세균군집의 정점별 평균값은 다른 정점보다 담수유입 수역인 1번 정점에서 매우 높은 밀도를 보였다. 이화학적 조사와 미생물학적 조사 결과를 고찰했을 때 강진만 생태계는 계절에 따라 2~4개 요인에 의하여 조절되는 것으로 보이며, 주로 담수유입, 영양염류, 염분도 그리고 수온 등에 의하여 영향을 받는 것으로 판단되었다. 이들 결과로 볼 때 강진만의 생태계에서 환경 요인의 영향은 다른 만 (광양만, 진해만, 마산만 등)에 비해 상대적으로 적었던 것으로 사료된다.

• Molecules and Cells
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• 제41권8호
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• pp.781-798
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• 2018

Plants have evolved strategies to cope with drought stress by maximizing physiological capacity and adjusting developmental processes such as flowering time. The WOX13 orthologous group is the most conserved among the clade of WOX homeodomain-containing proteins and is found to function in both drought stress and flower development. In this study, we isolated and characterized OsWOX13 from rice. OsWOX13 was regulated spatially in vegetative organs but temporally in flowers and seeds. Overexpression of OsWOX13 (OsWOX13-ov) in rice under the rab21 promoter resulted in drought resistance and early flowering by 7-10 days. Screening of gene expression profiles in mature leaf and panicles of OsWOX13-ov showed a broad spectrum of effects on biological processes, such as abiotic and biotic stresses, exerting a cross-talk between responses. Protein binding microarray and electrophoretic mobility shift assay analyses supported ATTGATTG as the putative cis-element binding of OsWOX13. OsDREB1A and OsDREB1F, drought stress response transcription factors, contain ATTGATTG motif(s) in their promoters and are preferentially expressed in OsWOX13-ov. In addition, Heading date 3a and OsMADS14, regulators in the flowering pathway and development, were enhanced in OsWOX13-ov. These results suggest that OsWOX13 mediates the stress response and early flowering and, thus, may be a regulator of genes involved in drought escape.

• Journal of Ecology and Environment
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• 제47권3호
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• pp.134-145
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• 2023

Background: The flowering and fruiting periods play an important role in biological processes. The deciduous dipterocarp forest is an important forest type in Thailand, however the phenological studies are still limited, particularly in different plant life forms. Thus, the present study focused on the flowering and fruiting phenology of herbs, climbers, shrubs, and trees in the deciduous dipterocarp forest at Lampang province of Northern Thailand. Field visits were made to record plant life forms and observe reproductive phenological events at monthly intervals from November 2018 to October 2019 and September to December 2020. Results: The phenological observations were based on 126 species of 45 families and 102 genera. Flowering and fruiting periods showed similar patterns in herbaceous plants, climbers, and shrubs. Most of these species produced flowers and fruits from the end of the rainy season (October) to the winter season (November-January). Whereas most of flowering and fruiting trees were found from the summer season (March-April) to the beginning of the rainy season (May-June). Most of the dry-fruited species occurred during the dry period (winter and summer seasons), while the majority of fleshy-fruited species dominated in the wet period (rainy season). The statistical analysis supported the phenological patterns of flowering and fruiting in the present study. There were significant negative correlations between the number of flowering and fruiting species and temperature. The number of flowering and fruiting species is significantly impacted by the interaction between seasons and plant life forms. Conclusions: Plant life form seems to be the important factor that affects the different phenological patterns in the studied plants. The abiotic and biotic factors play major roles in reproductive phenology. However, long-term study and in-depth phenological observations are necessary for better understanding.

• 한국수산과학회지
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• 제48권4호
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• pp.489-497
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• 2015

To reveal the spatial and temporal variability in the distribution, growth, and maturation of skipjack tuna Katsuwonus pelamis in the western tropical Pacific, we compared two El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) signals and the sea surface temperature (SST) in the main fishing area with fishery and biological data. An index of skipjack tuna distribution was calculated using Korean purse seine fishery data from 1985 to 2003. Biological data for skipjack tuna were collected monthly from Korean catches during the 1994-2003 period. The catch was more closely related to the SST in the main fishing area than to the ENSO signals. However, cross-correlated function analysis showed delayed interactions between abiotic and biotic factors. The El $Ni{\tilde{n}}o$ events preceded the eastward movement of the fishing center by 2-3 months. El $Ni{\tilde{n}}o$ had a positive effect on the skipjack tuna catch, and the change in the Southern Oscillation Index (SOI) preceded the catch fluctuation by ca. 5-7 months. In addition, negative El $Ni{\tilde{n}}o$ effects on gonad maturation and the mean length of skipjack tuna were detected with time lags of 12 and 7 months, respectively. The length frequency indicated that the regime-specific growth pattern at each discrete period seemed to be related to the ENSO.

• 환경생물
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• 제34권4호
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• pp.281-291
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• 2016

Bloom of small centric diatom Stephanodiscus is quite occasional in winter season in temperate freshwater ecosystems. It often leads to degradation of water quality and affects the quality of supplied drinking water. In a previous study, we have found that naphthoquinone (NQ) 4-6 derivate is an effective tool for efficient mitigation of natural S. hantzschii blooms. In the present research, polylactide (PLA) and agar foam were used as immobilized agent for NQ 4-6 to improve the efficiency of NQ 4-6 compound releasing process for its application under various field conditions. Mesocosm experiments at 10 ton scale suggested that the abundance of S. hantzschii was continuously increased in the control and upon treatment of the mesocosm with immobilized NQ 4-6 from PLA and agar foam. Their algicidal activities were 78.8% and 77.1%, respectively, on S. hantzschii after 10 days. In the mesocosm experiments, the dynamics of biotic (bacteria, HNFs, ciliates, zooplankton) and abiotic (water temperature, dissolved oxygen, pH, conductivity, nutrients) factors remained unaffected. They exhibited similar trends in the control and treatment groups. Therefore, the immobilized NQ 4-6 from PLA and agar foam has potential to be used as an alternative algicidal substance to effectively mitigate natural S. hantzschii blooms under various field conditions. In addition, it not only can be used to control S. hantzschii, but also is an effective technique. The immobilized NQ 4-6 showed stable controlled release in desired system.

• 한국초등과학교육학회지:초등과학교육
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• 제39권3호
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• pp.399-411
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• 2020

This study aims to explore how elementary students perceive and approach the issue of plastic debris in marine habitats by examining students' perspectives on the ecosystem and environmental solutions. The study was conducted to 143 Grade Four elementary school students in Seoul. After implementing two class-units on plastic waste, students' constructed responses on the problem of and solutions to plastic debris in marine habitats were collected. Data were analyzed through semantic network analysis and the keywords were visualized to reflect their relationships. Furthermore, students' responses on how they perceive environmental problems were further analyzed based on the following analysis criteria: students' perspectives on the ecosystem, the level of complexity of food chain(s), and the scope of their perspective. Also, student responses on environmental solutions were classified to be either at a personal or social level. Through semantic network analysis, keywords identified for students' perceptions on the problem were the sea, plastic, debris, animals, living things, humans, extinction, while keywords extracted for the solutions were plastic, debris, recycling, disposable, and I. Based on the analysis criteria, it was found that students were well aware of the food chain concept, could perceive the ecosystem as having comprised of both biotic and abiotic factors, and could approach the problem beyond the scope of the marine environment. Also, most students mentioned the solutions only at a personal level. Based on the findings, implications on how to move forward in educating environmental issues related to the ecosystem in science education is further discussed.

• 한국환경생태학회지
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• 제24권1호
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• pp.78-86
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• 2010

국내 주요 도시에서 수행된 비오톱유형 분류는 생물서식처 관점보다는 토지이용 개념에 한정되어 분류되었고, 생태적 가치에 따라 상세하게 분류되지 못하였다. 비오톱유형은 지역적 특성을 고려하여 생물서식처 관점에 따라 분류되어야 한다. 본 논문은 비오톱유형 분류에 사용되는 분류위계, 분류항목, 분류요인, 분류지표, 분류기준, 분류key 등 분류인자의 개념적 틀을 명확하게 설정하고 사례도시의 비오톱유형 분류결과에 적용하여 문제점을 고찰하고 비오톱유형 분류체계 개선방향을 제안하였다. 비오톱유형 분류체계는 위계별로 분류의 기본 수준과 기준을 마련하여 일관된 분류 특성을 가져야 한다. 분류지표는 생물적 요인, 무생물적 요인, 인간행태적 요인을 고려하여 적용되어야 한다. 비오톱유형은 일반인들과 계획가들이 이해하기 쉽도록 분류지표와 분류key의 표준화와 더불어 지역 비오톱 특성을 반영할 수 있도록 분류key와 분류기준의 특성화를 반영하는 것이 필요하다.

• 자원환경지질
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• 제42권5호
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• pp.395-401
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• 2009

스멕타이트-일라이트 (SI)의 전이 반응은 쇄설성 퇴적암 지역에 흔히 볼 수 있는 광물 반응이다. 지난 40여년 동안 SI 전이 반응의 중요성에 대한 논문들이 많이 출간되었는데 이는 스멕타이트가 일라이트로 변하는 정도 즉 "illitization" 이 석유의 개발, 퇴적물의 화학적 변화 및 물리적 성질변화 에 많은 연계성이 있기 때문이다. 기존의 S-I 상전이에 대한 메커니즘 연구에서는 layer-by-layer reaction 에 의한 solid state 반응 혹은 dissolution/precipitation 반응으로 집약되지만 박테리아 반응의 역할을 전혀 고려하지 않았다. 무산소 환경에서 박테리아와 점토광물의 반응에 대한 연구, 특히 스멕타이트와 철 환원 박테리아의 반응 작용에 대한 연구에서는 철 환원 박테리아가 스멕타이트 구조 속에 있는 철을 환원시켜 에너지를 얻는다고 밝혀졌다. 최근 발표된 논문들은 미생물의 철 환원 작용에 의하여 S-I 상전이가 일어날 수 있다고 보고되었는데, 이는 기존의 상전이에 대한 개념에 즉 고온, 고압, 오랜 시간이 S-I 전이의 필수 조건이라는 일반적인 해석에 반하는 것으로 새로운 연구 분야의 가능성을 시사하고 있다. 현재까지 발표된 논문에 의하면 박테리아가 S-I 반응을 촉진지킴으로 고온, 고압, 혹은 상당시간의 속성작용이 전제조건으로 작용하지 않을 수 있다는 가능성을 시사한다. 하지만 박테리아가 철을 환원함과 동시에 스멕타이트를 일라이트로 전이시킴에 있어서의 메커니즘에 대한 이해는 아직 미비하다. 따라서 이 논문에서는 현재까지 밝혀진 SI 반응을 살펴보고, 미생물 광물간의 반응작용에 있어서 연구 방법을 소개함을 목적으로 한다.