• ALGAE
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• 제18권3호
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• pp.207-215
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• 2003

Dynamics of phytoplankton communities were investigated at five stations in Youngsan River from December 1995 to November 1996. Phytoplankton were identified to the total of 466 taxa, which were composed of 136 genera, 438 species, 27 varieties and 1 forma. The standing crops ranged 1,163-50,765 cells ${\cdot}ml^{-1}$ during the investigation periods. The variation of classes was in order to Chrysophyceae - Bascillariophyceae - Chlorophyceae at St. 1 and was only Bacillariophyceae at the other stations. The dominant species were 12 taxa including Aulacoseira ambigua, A. garnulata, Cyclotella meneghiniana, C. pseudostelligera, Chlorella vulgaris, Dinobryon sertularia, Flagilaria elliptica, Monoraphidium contortum, Micractinium pusillum, Nitzschia palea, Scenedesmus grahneisii and Stephanodiscus hantzschii f. tenuis. The standing crops of dominant species ranged from 10.6% to 94.7%. The genus Dinobryon in Chrysophyceae was dominant species at St. 1 in December 1995, but not recorded in the other months. The dominant species were composed with the planktonic diatoms from winter to spring and were the tychoplanktonic and the benthic species at St. 2-5 from summer to fall. The relationships between total standing crops and water temperature, pH, $NH_4$, $NO_2$, $NO_3$ and $PO_4$ showed low positive or negative coefficients. Stephanodiscus hantzschii f. tenuis had low positive or negative coefficients with water temperature, $NH_4$, $NO_2$, $NO_3$ and $PO_4$. The fluctuations of standing crops in the Youngsan river phytoplankton community were not caused by a single factor but controlled by the complex factors with interaction between phytoplankton community and envirowmental factors.

• ALGAE
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• 제18권3호
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• pp.183-190
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• 2003

Except for a group I intron in trnL-uaa occuring in eubacteria and plastids, group I introns are rarely documented in plastid genomes. Here, we report that a green alga, Caulerpa sertularioides, contains three group IA3 introns in the 16S gene (cpSSU), CS-cpSSU.i1, CS-cpSSU.i2 and CS-cpSSU.i3. Each intron has an open reading frame with LAGLIDADG motifs. CS-cpSSU.i1orf and CS-cpSSU.i3orf occur at Loop 6 in the intron secondary structure and CScpSSU. i2orf at Loop 8. CS-cpSSU.i1orf and CS-cpSSU.i2orf contain both LAGLI-DADG motifs but CS-cpSSU.i3orf has only one. CS-cpSSU.i1 and CS-cpSSU.i2 share the insetion sites and the ORFs at Loop 6 and 8 with CpSSU·1 and CpSSU·2 introns of Chlamydomonas pallidostigmatica (Chlorophyceae). In contrast, CS-cpSSU.i3, containing 28 copies of GAAATAT at Loop 6, is a novel intron found only in Caulerpa sertularioides. Possible scenarios of the evolution of the three introns and their possible use in systematic research are discussed.

• 한국환경보건학회지
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• 제18권2호
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• pp.26-38
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• 1992

This study was carried out to investigate phytoplankton distributions and water properties at 6 sampling places in Yongsan lake during the period from Jun. 30 to Nov. 17, 1991.Results obtained were as follows: 1. At sampled sites, BOD value ranges from 1.0~14.0 mg/l except Sangmongtan where it was 14.0 mg/l on Nov. 17. 2. T-N and T-P were generally high and the former was 0.26~1.42 mg/l, the latter 0.010~0.158mg/l. 3. At all sampled places, salinity was in the range of 0.04~0.57% but especially downstream of Yongsan lake was high, 0.39~0.57% on Oct. 27. 4. The phytoplankton identification in this survey period showed Cyanophyceae is 11 genera 14 species, Bacillariophyceae 13 genera 22 species, Chlorophyceae 30 genera 55 species: total 54 genera 91 species. 5. Dominant species were Anacystis aeruginosa, Lyngbya contorta, Anabeana Sp, Melosira granulata, Melosira granulata var. angustissima, Dictyosphaerium pulchellurn and Actinastrurn hantzschii var. fiuviatile during the period from summer to fall. 6. Lyngbya contorta was seemed to adapt to the circumstance of low transparency. 7. Phytoplankton distributions were seemed to be influenced by salinity and thransparency. And so they might appear much fewer in the downstream than the upperstream in Yongsan lake.

• 한국환경보건학회지
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• 제7권2호
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• pp.97-105
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• 1981

Water Pollution of Gwangju Stream was examined for four months from 22 March 1981 to 7 June, 1981. For checking the water pollution, 6 sampling positions were selected 5 from main stream. We assumed that the water pollution of Gwangju stream was due to the organic materials, which came from the domestic sewage. The apparatus for this test were pH meter (Orion model 301), Dissolved Oxygen & Temperature meter(Delta model 1010). The results we obtained are as follows: 1. The average range for mid-stream(sp. 3, 4) was 3. 10~2.73ppm of Dissolved Oxygen(DO), 80.23~102.95ppm of Biochemical Oxygen Demand (BOD), 195. 10~165.90ppm of Suspended Solid (SS), 6.6~6.7 of pH. 2. The plankton identification in this survey period showed Cyanophyceae is 4 genera 5 species, Bacillariophycea 11 genera 14 species, Chlorophyceae 8 genera 15 species and Zooplankton 6 genera 7 species: total 29 genera 41 species. 3. To appear dominant plankton in polluted water, there were Paramecium, Euglena and Oscillatoria. 4. The results of biological water analysis were as follows: st. 1 was B-mesosaprobic to oligosaprobic, but st. 4 and st. 5 at stream in the midtown area seemed to be polysaprobic.

• 한국물환경학회지
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• 제25권4호
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• pp.494-501
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• 2009

Probabilistic Ecological risk assessment (PERA) is extensive approach to qualify and quantify risk on the multi species based on species sensitivity distribution (SSD). As a while, deterministic ecological risk assessment (DERA) considers the comparison of predicted no-effect concentration (PNEC) and predicted exposure concentration (PEC). DERA is used to determine if there is potential risk or no risk, and it doesn't consider the nature variability and the species sensitivity. But PERA can be more realistic and reasonable approach to estimate likelihood or risk. In this study, we compared PERA used in developed countries, and proposed PERA applicable for the Korean water environment. Taxonomic groups were classified as "class" level including Actinopterygill, Branchiopoda, Chlorophyceae, Maxillapoda, Insects, Bivalvia, Gastropoda, Secernentea, Polychaeta, Monocotyldoneae, and Chanophyceae in this study. Statistical extrapolation method (SEM), statistical extrapolation method $_{acutechronicratio}$ ($SEM_{ACR}$) and assessment factor method (AFM) were used to calculate the ecological protective concentration based on qualitative and quantitative levels of taxonomic toxicity data. This study would be useful to establish the PERA for the protection of aquatic ecosystem in Korea.

• 한국패류학회지
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• 제20권1호
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• pp.27-34
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• 2004

Based on both field and laboratory experiments, seasonal changes in the species composition and abundance of phytoplankton in the gut contents of the jedo venus clam, Protothaca jedoensis, and its feeding selectivity were investigated. The phytoplankton in the gut contents comprised Bacillariophyceae (diatom), Chlorophyceae, Chrysophyceae, and Dinophyceae, of which the diatoms being the most predominant throughout the year. Although the number of species and the abundance of phytoplankton in the sea water were always more diverse and more abundant than in the gut contents, the relative number and abundance were generally similar in the seawater and in the gut contents. In the laboratory experiments, the relative abundances of Coscinodiscus marginatus and Thalassirosira eccentrica were much more higher in the gut contents than any other algal species, while Paralia sulcata, Skeletonema costatum, and Eucampia zodiacus were abundant in order of cell density in the ambient water. These results suggest that P. jedoensis may feed preferably on single algal cell or smaller chains of algal cells.

• Journal of Plant Biology
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• 제35권1호
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• pp.69-75
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• 1992

해산 녹조 납작파래 (Enteromorpha compressa)의 조위에 따른 생물계절적 특성을 이해하기 위하여 여천군 돌산도백포리 해안에서 1990년 5월부터 1991년 4월까지 출현빈도, 길이 및 성숙도를 매달 조사하였다. 수온은 모든 조위간에서 차이가 없었으나 출현빈도의 연준 변동과 높은 상관을 보였다. 염분도와 부유성 고형물질량은 상부와 중부 그리고 상부와 하부 간에 차이가 있었으나 생물계절과는 상관이 없었다. 조간대 상부에서 나타난 본 식물의 출현빈도는 중부와 하부에 비해 대체로 항상 작았다. 또한 상부의 개체들은 조사기간 동안 최소한 2회에 걸친 생활사를 보인 반면에 중부와 하부의 개체들은 약 6개월에 걸쳐 한번의 생활사를 보였다.

• 한국환경과학회지
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• 제21권3호
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• pp.313-326
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• 2012

Three embankments, namely Changpo, Bokkil and Guil, in Chunggye Bay were investigated to assess the influence of environmental changes to phytoplankton size structure, distribution of species and standing crops. Three stations was sampled near at each embankment in Nov. 2006, Feb. 2007, May 2007 and Aug. Phytoplankton were classified into net-size (>20${\mu}m$) and nano-size (<20${\mu}m$). In summer, the freshwater discharge seemed to have influence in the decrease of salinity and in the increase of turbidity, ammonium and phosphorus concentrations. Chl a concentration and phytoplankton abundance in Feb. 2007 were observed to be generally higher in all stations compared to other periods. Net-size phytoplankton was observed to be higher in Feb. 2007 and May 2007 compared to nano-sized phytoplankton. However, there was shift in phytoplankton composition in Nov. 2006 and Aug. 2007. Phytoplankton under seven class (Bacillariophyceae, Chlorophyceae, Chrysophyceae, Cryptophyceae, Cyanophyceae, Dinophyceae, Euglenophyceae) was identified during the study period. It was found out that the major phytoplankton class was Bacillariophyceae. Phytoplankton was more diverse in autumn compared to any other season. Cyanophyceae was increased in summer. In rainy season, change in physical factors (salinity, transparency) seemed to have more influence on phytoplankton growth compared to inorganic nutrients.

• ALGAE
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• 제36권2호
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• pp.73-90
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• 2021

Relative to the large number of photosynthetic dinoflagellate species, only a select few possess proteinaceous, carotenoid-rich eyespots which have been demonstrated in other algae to act in phototactic responses. The proteins comprising the different categories of dinoflagellate eyespots are positioned in or near the peridinin-containing photosynthetic plastid membranes which are composed primarily of two galactolipids, mono- and digalactosyldiacylglycerol (MGDG and DGDG). Within eyespot-containing dinoflagellates, this arrangement occurs mostly in those with secondary plastids, although some dinoflagellates with tertiary plastids of diatom origin are known to possess eyespots. We here provide an examination of the MGDG and DGDG composition of eyespot-containing dinoflagellates with secondary, peridinin-containing plastids and tertiary plastids of diatom origin to address the fundamental question of whether eyespots and their component proteins and carotenoids are associated with alterations in galactolipid composition when compared to eyespot-lacking photosynthetic dinoflagellates. This is an important question because the dinoflagellate eyespot-plastid membrane system can be considered a more complicated and evolved state of plastid development. Included in this examination are data on the previously unexamined peridinin- and type A eyespot-containing dinoflagellate Margalefidinium polykrikoides, and the type D eyespot-containing, aberrant plastid "dinotom" Durinskia baltica. In addition, we have reviewed the galactolipid composition of algae from the Chlorophyceae, Cryptophyceae, and Euglenophyceae as a comparison to determine if algal classes apart from the Dinophyceae contain altered galactolipids in association with eyespots. We conclude that the presence of an eyespot in dinoflagellates and other algae is not associated with noticeable changes in galactolipid composition.

• 한국환경과학회지
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• 제31권5호
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• pp.431-445
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• 2022

The Gwangju Stream is a major tributary of the Yeongsan River. To maintain environmental and ecological functions in the stream, the flow is secured by natural water from the Mudeung Mountain as well as waters discharged from Lake Juam and the Gwangju sewage treatment plants. A substantial amount of water is supplied into the upper reaches of Gwangju Stream from Lake Juam. To examine the ecological effects of the water input from Lake Juam on the Gwangju Stream, a field survey of phytoplankton community species and an evaluation of water properties was conducted at five stations, from station GJ1 before the inflow to station GJ5 in the lower region. Nutrient levels decreased in the vicinity of the Lake Juam inflow, suggesting that this water inflow can contribute to the reduction of eutrophication in the stream. The phytoplankton community was mainly composed of Bacillariophyceae, Chlorophyceae, and Cyanophyceae, and the community structure was similar to that of the other study sites located near the water inflow regions. The inflow of water from Lake Juam can affect water quality and the phytoplankton community over a limited area, reducing eutrophication and increasing water flow in the Gwangju Stream.