• ALGAE
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• 제22권3호
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• pp.185-192
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• 2007

A study was carried out in nine fertilized fish ponds under three treatments (T-I, T-II and T-III) at Bangladesh Agricultural University, Mymensingh to see the bloom of euglenophytes with the intention of observing its impact on the growth of fish in culture condition. Some water quality parameters viz., temperature, dissolved oxygen, pH, PO4-P and NO3-N concentration and some biological parameters viz., phytoplankton population and growth of fish were monitored at fixed intervals. Euglenophytes showed a heavy bloom in late August in the ponds of T-II. The bloom was occurred by the genera, Euglena, Phacus and Trachelomonas of which Euglena was the most dominant genus. In relation of water quality parameters with euglenophytes bloom, it was hypothesized that euglenophytes prefers higher temperature and acidic environment with higher nutrient concentrations. Acidic environment and nutrient enrichment enhanced the bloom of euglenophytes which hampered the growth of other beneficial algal groups (chlorophytes and bacillariophytes) and fish. Due to heavy bloom, the fishes breathed with difficulty at the surface. The fishes in the heavy bloom ponds presented the weight values were lower than verified for those in the ponds where the bloom did not occur. Total production (calculated) of fish in different treatments ranged from 1355.89 to1760.63 kg ha–1 with significantly (p < 0.05) lowest in the ponds of T-II.

• Journal of Ecology and Environment
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• 제46권2호
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• pp.99-110
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• 2022

Background: Many investigations on phytoplankton from the Nakdong River carried out. However, since the weirs were constructed, only changes in phytoplankton biomass and dominant species have been restrictively studied in phytoplankton investigations in the Nakdong River. Added to this, any investigation on the phytoplankton flora has not been done in the Nakdong River. The aim of this study is to elucidate the characteristics of phytoplankton communities in the Nakdong River with the weirs built in it. Results: We observed a total of 103 taxa of Euglenophytes belonging to 8 genera from middle-lower part of the Nakdong River. The genus Trachelomonas was the most abundant group making up 40 taxa, followed Lepocinclis (20), Phacus (17), Strombomonas (14), Euglena (5), Colacium (3), Monomorphina (3) and Menoideum (1). Among them, a total of 22 taxa including Colacium (1), Lepocinclis (8), Phacus (4), Strombomonas (4) and Trachelomonas (5) were reported for the first time in Korea, and 86 taxa including those new to Korea were first recorded in the Nakdong River. All the species are illustrated with photomicrographs, and new to Korean species briefly discussed with regard to their taxonomy together with photomicrographs. Conclusions: The present study, a total of 22 taxa including one species of Colacium, 8 taxa of Lepocinclis, 4 taxa of Phacus, 4 taxa of Strombomonas and 5 taxa of Trachelomonas were reported for the first time in Korea, and 86 taxa including those new to Korea were first recorded in the Nakdong River.

• ALGAE
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• 제21권1호
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• pp.61-73
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• 2006

Sixty taxa of Euglenaceae belonging to 19 species of Euglena, 1 species of Colacium, 8 species of Lepocinclis, 22 species of Phacus and 10 species of Trachelomonas were reported from different habitats of Orissa state in the east cost of India. All the taxa were recorded for the first time from this region.

• 한국수산과학회지
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• 제37권3호
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• pp.215-225
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• 2004

Biomass and community composition of microphytobenthos in the Saemankeum tidal flat were studied by HPLC analysis of the photosynthetic pigments from November 2001 to November 2002. The environmental factors of sediment were also investigated to examine the relationship between microphytobenthos biomass and sedimentary environments. The detected photosynthetic pigments of microphytobenthos were chlorophyll a, b, c, fucoxanthin, 19'-hexanoyloxyfucoxanthin, violaxanthin, diadinoxanthin, alloxanthin, diatoxanthin, zeaxanthin+lutein, peridinin and beta-carotene. Pheophytin a, the degradation product of chlorophyll a, was also detected. The results of pigmen analysis suggest the presence of diatom (fucoxanthin), euglenophytes (chlorophyll b), chlorophytes (chlorophyll b + lutein), cyanobacteria (zeaxanthin), cryptophytes (alloxanthin), chrysophytes (fucoxanthin + violaxanthin), prymnesiophytes (19'-hexanoyloxyfucoxanthin) and dinoflagellates (peridinin). Chlorophyll a concentration in the top 0.5 cm of sediment was in the range of $0.24\;mg{\cdot}m\^{-2}\;-32.11\;mg{\cdot}m\^{-2}$ in the study area. The increase of chlorophyll a concentration in the spring indicates the occurrence of a microphytobenthic bloom. In the summer, there was a sharp decrease of the chlorophyll a concentration which was probably due to high grazing activity by macrobenthos. The annual mean chlorophyll a concentration in the study area was low compared to that in most of other tidal flat areas probably due to active resuspension of microphytobenthos and high grazing activity by macrobenthos. There was no clear relationship between microphytobenthos biomass and sedimentary environments because of a large variety of physical, chemical and biological factors, Pigment analysis indicated that while diatoms were dominated in the microphytobenthic community of the Geojon tidal flat, euglenophytes and/or chlorophytes coexisted with diatoms in the Mangyung River tidal flat.

• 한국산학기술학회논문지
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• 제11권9호
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• pp.3610-3614
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• 2010

새만금 수역에서 2006년 5월부터 2007년 11월까지 8회의 조사를 통해 표영환경의 미소조류군집의 분류군 조성과 다양성지수 등을 연구하였다. 조사수역 미소조류군집의 출현종은 총 191종으로 규조류(Diatom) 94종, 녹조류(Chlorophyte) 31종, 와편모조류(Dinoflagellate) 24종, 남조류(Cyanophyte) 24종, 유글레나조류(Euglenophyte) 11종, 규질 편모류(Silicoflagellate) 3종, 크립토조류(Cryptophyte) 1종, 기타 미동정 미소편모조류 3종 등으로 구성되었다. 연구기간 동안 연구수역 미소조류군집의 다양성 지수는 시공간적으로 변화가 지속되어 일정한 변화의 규칙성을 찾기 어렵다. 이는 공사의 진행과 방조제 수문개폐에 따른 수질환경의 급변 등 인위적 요인이 부유성 미소조류에 스트레스로 작용한 것으로 보인다.

• Ocean and Polar Research
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• 제23권3호
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• pp.245-253
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• 2001

To investigate the community structures and the their seasonal variation of phytoplankton and zooplankton, a study was conducted at 6 selected stations during the period from April 1999 to October 2000 in the marine ranching ground off Tongyeong. One hundred ninety species of phytoplankton were identified, including 146 diatoms, 38 dinoflagellates, 4 silicoflagellates and 2 euglenophytes. Phytoplankton standing crops varied extensively by months and stations, ranging from $3.0{\times}10^4\;cells/l\;to\;1.0{\times}10^6\;cells/l.$. The dominant species varied from the vertical distribution as well as seasonal changes. In April and July 1999, Skeletonema costatum and Ceratium fusus were predominant in both the surface and the bottom water columns. Leptocylindrus danicus was the dominant species in April and June 2000, and Thalassiosira spp. were also predominant in bottom waters in June 2000. Pseudonitzschia pungens and Chaetoceros spp. were the dominant species at both surface and near bottom waters in August and October 2000, respectively. Zooplankton abundance was comparatively high in April and July in 1999, and April, June, and October in 2000, but extremely low in November 1999. The density of dominant zooplankton was higher in 2000 than in 1999. Copepods were the most predominant group except for July 1999 when the bivalve larvae showed extremely high abundance. Acartia omorii and Oithona similis were the dominant or subdominant copepod species mainly in April 2000, and June/July, while O. davisae and O. plumifera had peaks in August and October 2000. Corycaeus affinis and Paracalanus sp. also showed higher peaks in April and June (or July), even though they occurred in all sampling time. Centropages abdominalis occurred abundantly only in April 1999. Oikopleura dioica, a gelatinous zooplankton, was another important zooplankton, showing high density in all samples except in July 1999.

• Ocean and Polar Research
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• 제35권1호
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• pp.39-50
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• 2013

Biomass and community composition of microphytobentos in tidal flats were studied by HPLC analysis and also investigated to examine the relationship between microphytobenthic pigments and Adenosine-5' triphosphate (ATP) as an index of total microbial biomass in intertidal environments (muddy and sandy sediment) of Gyeonggi Bay, west coast of Korea. Microphytobenthic pigments and ATP concentration in muddy sediment were the highest at the surface while the biomass of microphytobenthos in sandy sediment was the highest at the sub-surface (0.75 cm sediment depth). The detected pigments of microphytobenthos were chlorophyll a, b (euglenophytes), $c_3$, peridinin (dinoflagellates), fucoxanthin (diatom or chrysophytes), diadinoxanthin, alloxanthin (cryptophytes), diatoxanthin, zeaxanthin (cyanobacteria), ${\beta}$-carotein, and pheophytin a (the degraded product of chlorophyll a). Among the pigments which were detected, the concentration of fucoxanthin was the highest, indicating that diatoms dominated in the microphytobenthic community of the tidal flats. There was little significant correlation between OC (Organic Carbon) and ATP in both sediments. However, a positive correlation between chlorophyll a concentration and ATP concentration was found in sandy sediment, suggesting that microbial biomass could be affected by labile OC derived from microphytobenthos. These results provide information that may help us understand the relationship between microphytobenthos and microbial biomass in different intertidal sediment environments.

• 한국해양학회지:바다
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• 제10권1호
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• pp.8-18
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• 2005

강화도 장화리 펄 조간대 지역에서 2002년 5월-2004년 4월까지 저서미세조류의 계절분포를 조사하였으며, 저서미세조류의 일차생산력 측정과 HPLC를 이용한 색소분석 방법으로 저서미세조류의 생산능력 및 분류군별 분포를 파악하였다. 강화도 갯벌에서 저서미세조류는 조간대 중부에서 많은 현존량을 보였다 강화도 갯벌에서 저서미세조류의 계절별 현존량 변동은 $2.3-140.9{\times}10^5\;cells\;cm^{-2}$의 범위로 하계와 동계에 낮은 현존량을 보였고 2003년 2월에서 4월까지 저서미세조류의 대증식 헌상이 나타났다. 저서미세조류는 대부분 저서성 돌말류가 우점종으로 출현하였고, 특히 연중 Paralia sulcata가 전 정점에서 우점하여 출현하였다. 그외에 Cylindrotheca closterium과 Nitzschia sp.가 2월과춘계에 크게 우점하였다. HPLC 색소분석을 통한 저서미세조류 군집조성은 돌말류를 포함하여 유그레나류, 남조세균, 녹조류, 은편모조류, 황갈조류, 와편모조류 등 다양한 종류가 출현하고 있는 것으로 나타났다. Chl a의 함량은 1.18-34.25 mg $m^{-2}$의 범위로 평균 7.60 mg $m^{-2}$을 보였다. Fuco/Chl a는 평균 0.7로 나타나 연구기간동안 돌말류가 전체 저서미세조류 생물량의 대부분을 차지하고 있음을 보여주었으며 Chl b/Chl a는 평균 0.17로 유그레나류와 녹조류가 일정 시기에 서로 공존하여 서식하는 것으로 나타났다. 평균 일차생산력의 화는 4.2-113.0 mgC $m^{-2}\;hr^{-1}$비 범위로 평균 33.9 mgC $m^{-2}\;hr^{-1}$로 나타났고, 초기기울기 $(\alpha)$의 변화범위는 0.002-0.005$(mgC\;mgchl-a^{-1}\;hr^{-1}){\cdot}({\mu}E\;m^{-2}\;s^{-1})^{-1}$로 측정되었다. 동화계수(Pm)는 0.50-1.32 mgC $mgchl-a^{-1}\;hr^{-1}$의 변화범위를 보였고, 일일 일차생산력은 20.9-678.1 mgC $m^{-2}\;d^{-1}$ 범위로 평균 206.7 mgC $m^{-2}\;d^{-1}$을 보여 일반적인 갯벌에서의 생산력 범위를 보였다.

• ALGAE
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• 제32권4호
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• pp.285-308
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• 2017

Cochlodinium polykrikoides red tides have caused great economic losses in the aquaculture industry in many countries. To investigate the roles of metazooplankton in red tide dynamics of C. polykrikoides in the South Sea of Korea, the abundance of metazooplankton was measured at 60 stations over 1- or 2-week intervals from May to November 2014. In addition, the grazing impacts of dominant metazooplankton on red tide species and their potential heterotrophic protistan grazers were estimated by combining field data on the abundance of red tide species, heterotrophic protist grazers, and dominant metazooplankton with data obtained from the literature concerning ingestion rates of the grazers on red tide species and heterotrophic protists. The mean abundance of total metazooplankton at each sampling time during the study was 297-1,119 individuals $m^{-3}$. The abundance of total metazooplankton was significantly positively correlated with that of phototrophic dinoflagellates (p < 0.01), but it was not significantly correlated with water temperature, salinity, and the abundance of diatoms, euglenophytes, cryptophytes, heterotrophic dinoflagellates, tintinnid ciliates, and naked ciliates (p > 0.1). Thus, dinoflagellate red tides may support high abundance of total metazooplankton. Copepods dominated metazooplankton assemblages at all sampling times except from Jul 11 to Aug 6 when cladocerans and hydrozoans dominated. The calculated maximum grazing coefficients attributable to calanoid copepods on C. polykrikoides and Prorocentrum spp. were 0.018 and $0.029d^{-1}$, respectively. Therefore, calanoid copepods may not control populations of C. polykrikoides or Prorocentrum spp. Furthermore, the maximum grazing coefficients attributable to calanoid copepods on the heterotrophic dinoflagellates Polykrikos spp. and Gyrodinium spp., which were grazers on C. polykrikoides and Prorocentrum spp., respectively, were 0.008 and $0.047d^{-1}$, respectively. Therefore, calanoid copepods may not reduce grazing impact by these heterotrophic dinoflagellate grazers on populations of the red tide dinoflagellates.

• 한국해양학회지:바다
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• 제12권3호
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• pp.200-210
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• 2007

아산만 식물플랑크톤의 하계 종조성 변화를 조사하기 위하여 2006년 6월, 7월, 8월에 매달 두 번씩 실시하였으며 조사 정점은 공간적 분포를 나타내는 5개 정점을 선정하여 조사하였다. 6월과 7월에 염분은 내만에서 감소하는 경향을 보였다. 영양염은 6월과 7월에 높았으나 8월에 낮은 경향을 보였다. 2006년 여름철 아산만에서 식물플랑크톤 군집은 규조류(62.8%), 와편모조류(17.3%), 은편모조류(14.8%), 유글레나류(1.0%), 남조류(0.9%), 녹조류(0.4%) 등 6종과 확인되지 않은 종(2.8%)이 포함되었다. 6월에는 와편모조류(주요하게 Prorocentrum sp.(29.6%))가 우점 하였고 총 현존량의 43.5%를 차지하였지만 7월과 8월에는 규조류(주요하게 Leptocylindrus sp.(21.4%), Chaetoceros sp.(27.6%))가 우점 하였으며 각각 총 현존량의 69.1%, 89.9%를 차지하였다. 이와 같이 하계에도 강우에 따라 아산만 각 정점에서의 우점속의 변화가 발생하였으며 이는 강우에 따른 담수유입이 하계 아산만 식물플랑크톤 종조성변화에 영향을 미치고 있음을 암시한다.