• ALGAE
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• 제34권4호
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• pp.267-275
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• 2019

Three new species of the genus Micractinium were collected from five localities on the South Shetland Islands in maritime Antarctica, and their morphological and molecular characteristics were investigated. The vegetative cells are spherical to ellipsoidal and a single chloroplast is parietal with a pyrenoid. Because of their simple morphology, no conspicuous morphological characters of new species were recognized under light microscopy. However, molecular phylogenetic relationships were inferred from the concatenated small subunit rDNA, and internal transcribed spacer (ITS) sequence data indicated that the Antarctic microalgal strains are strongly allied to the well-supported genus Micractinium, including M. pusillum, the type species of the genus, and three other species in the genus. The secondary structure of ITS2 and compensatory base changes were used to identify and describe six Antarctic Micractinium strains. Based on their morphological and molecular characteristics, we characterized three new species of Micractinium: M. simplicissimum sp. nov., M. singularis sp. nov., and M. variabile sp. nov.

• 생태와환경
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• 제34권2호통권94호
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• pp.90-97
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• 2001

국내에서 규모가 가장 큰 우포늪과 목포늪의 식물플랑크톤 군집의 특성을 파악하기 위해 1998년 1월부터 12월까지 식물플랑크톤의 종조성, 현존량, 우점종, 종 다양성 및 우점도 지수 등을 조사하였다. 우포늪의 식물플랑크톤 군집의 종조성은 녹조류와 규조류에 의해 우점되었으며, 현존량의 최고 밀도는 Oscillatoria sp.와 Micractinium psuillum이 bloom을 형성한 5월과 11월에 나타났다. 현존량의 강별 구성은 겨울을 제외한 전조사기간 동안 녹조류와 남조류가 우점하였고, 남조류는 4월부터 9월까지 그리고 11월에 높은 현존량을 나타내었으며 특히 5월과 7월에 매우 높은 우점도를 나타내었다. 규조류와 유글레나류는 1월과 2월에 현존량의 구성비가 높게 나타났으나 총 현존량이 적어 큰 의미는 없는 것으로 판단되었다. 우점종은 녹조류의 Micractinium pusillum은 가을과 겨울에 우점종으로 출현하였고, 남조류 Oscillatoria sp.가 두 정점에서 모두 4월부터 9월까지 그리고 11월에 우점종으로 출현하였으며, Actinastrum hantzschii var. fluviatile과 Monoraphidium contortum, 그리고 Cryptomonas sp. 등이 일시적인 우점종으로 출현하였으나 규조류는 우점종으로 출현하지 않았다. 종 다양성은 우점도 지수와 역의 상관도를 나타내었으며, 현존량이 최고치인 Micractinium pusillum과 Oscillatoria sp.가 bloom을 형성하여 절대적인 우점도를 나타낸 5, 6월 및 11월에 종 다양성은 가장 낮았다.

• 환경생물
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• 제38권1호
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• pp.61-70
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• 2020

A eukaryotic microalga was isolated from seawater in Janghang Harbor, Korea and its morphological, molecular, and physiological characteristics were investigated. Due to its simple morphology, no distinctive characters were found by morphological observation, such as light microscope or scanning/transmission electron microscopy (S/TEM). However, molecular phylogenetic evidence inferred from the concatenated small subunit (SSU) 18S rRNA and internal transcribed spacer (ITS) sequence data indicated that the isolate belonged to the newly described Micractinium singularis. Furthermore, it was clustered with Antarctic Micractinium strains and it also showed a psychrotolerant property, surviving at temperatures as low as 5℃. However, its optimal growth temperatures range from 15℃ to 25℃, indicating that this microalga is a mesophile. Additionally, gas chromatography-mass spectrometry (GC/MS) analysis showed that the isolate was rich in nutritionally important omega-3 polyunsaturated fatty acid, and high-performance liquid chromatography analysis (HPLC) revealed that the high-value antioxidant lutein was biosynthesized as an accessory pigment by this microalga, with glucose as the major monosaccharide. Therefore, in this study, a Korean marine M. singularis species was discovered, characterized, and described. It was subsequently added to the national culture collections.

• ALGAE
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• 제37권2호
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• pp.175-183
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• 2022

Polar microorganisms produce physiologically active substances to adapt to harsh environments, and these substances can be used as biomedical compounds. The green microalga Micractinium variabile KSF0031, which was isolated from Antarctica, produced phytol, a natural antimicrobial agent. Furthermore, several polyunsaturated fatty acids (PUFAs), including omega-3, exhibit antioxidant properties. Here statistical methods (Plackett-Burman design and Box-Behnken design) were used to optimize the culture medium of KSF0031 to improve biomass production, and K₂HPO₄, MgSO₄·7H ₂O, and ammonium ferric citrate green (AFCg) were selected as significant components of the culture medium. Changes in the concentration of K₂HPO₄ and MgSO₄·7H ₂O as positive factors and AFCg as a negative factor affected cell growth to a remarkable degree. The biomass production in a 100 L culture using the optimized medium for 24 d at 18℃ was improved by 37.5% compared to that obtained using the original BG-11 medium. The quantities of PUFAs and phytol obtained were 13 mg g^-1 dry cell weight (DCW) and 10.98 mg g^-1 DCW, which represent improved yields of 11.70% and 48.78%, respectively. The results of this study could contribute to an improved production of phytol and fatty acids from Antarctic microalgae in the biomedical industry.

• 한국환경과학회지
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• 제4권3호
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• pp.167-176
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• 1995

A study on phytoplankton community was carried out from June, 1992 to May, 1993 at selected stations in Hoedong Reservoir. The phytoplankton are identified as 176 taxa including 5 phylum, 67 genera. The important species in this reservoir were Asterionella formosa, C meneghiniana, Dictyosphaerium plilchellum, Fragilaria crotonensis, Melosira distans, M grantulata, M. granulata var. angustissima, M. granulate var. angntissima f. spirdis, Micractinium pussillum, Microcystis aeruginosa, Pundorina morn, Pediastrum boryanum, P. duplex, Peridinium sp., Scenedesmus quadriauda, Synedra acus, S. rumpens and S. ulna. The causative species of water bloom were identified as Microcystis aeruginsa, Trahellomonas hispida, Ceratium hirwdinella, Peridinium sp., Melosira italica, Staurastrum dorsidentiferum var. onatum in the area. During the study periods standing crcps of phytoplankton were maximum in August, 1992 and minimum in December 1992. The species dominance index and diversity index were ranged 24.7-99.9, 0.001-3.06, respectively. Key Words : phytoplankton community, causative species of water bloom, standing crops. dominance index, species diversity index.

• 상하수도학회지
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• 제18권2호
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• pp.247-253
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• 2004

Major species of Lake Deganuma has varied depending on the season. Namely, there are Micractinium pusillum, chlorella., Scenedesmus sp. shown up in spring season, Microcystis aeruginosa, Microcystis wesenbergii, Anabena spiroides in summer and autumn season and Cyclostephanos invisitatus, Diatoma in winter season in the Lake. As the number of plankton increased, the zeta potential on their surface of them decreased. For this reason, they were dispersed in the lake though the population increased. Zeta potential of M. aeruginosa showed -20mV when their outer size got smaller. As for coagulant dosing in DAF, large amount of coagulant was effective to get lots of sludge during water treatment.

• 대한환경공학회지
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• 제35권4호
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• pp.289-293
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• 2013

2002년부터 2012년까지 낙동강 하류 물금지역에서의 식물플랑크톤 우점종의 군집비율 변화를 조사한 결과, 식물플랑크톤 생체량(클로로필-a 농도)은 점진적인 감소 추세였던 반면, 우점종의 개체수는 증가 추세를 나타내었다. 식물플랑크톤 종별로 우점종의 연도별 개체수 비율변화에서 규조류는 감소 추세를 보인 반면, 남조류는 증가 추세를 나타내었다. 또한, 우점기간의 경우 매년 우점기간의 75% 이상을 규조류가 차지하였다. 연중 식물플랑크톤 비율변화에서 규조류는 11월에서 5월까지 매우 높은 우점비율을 보였고, 6월부터 9월까지도 우점일수의 56%~74%를 차지하여 연중 규조류가 300일 정도 우점하였다. 남조류는 6월부터 9월까지 개체수 및 우점기간의 68%~94% 및 26%~36%를 차지하였으며, 녹조류는 4월부터 9월까지 낮은 우점률을 나타내었다. 규조류와 남조류 우점종들의 연중 천이패턴은 규조류의 경우 12월~5월은 Stephanodiscus spp., 5월~10월은 Aulacoseira spp.와 Fragilaria spp.가 대부분 우점하였으며, 남조류의 경우 5월~11월에 Microcystis spp.가 대부분을 우점하였다. 또한, 녹조류는 4월~9월에 Actinastrum spp., Pediastrum spp., Micractinium spp. 및 Pandorina spp.가 우점하였다.

• 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.

• 상하수도학회지
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• 제36권5호
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• pp.249-260
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• 2022

The effect of permanganate oxidation was investigated as water treatment strategy with a focus on comparing the reaction characteristics of NaOCl and sodium permanganate (NaMnO₄) in algae (Monoraphidium sp., Micractinium inermum, Microcystis aeruginosa)-contained water. Flow cytometry explained that chlorine exposure easily damaged algae cells. Damaged algae cells release intracellular organic matter, which increases the concentration of organic matter in the water, which is higher than by NaMnO₄. The oxidation reaction resulted in the release of toxin (microcystin-LR, MC-LR) in water, and the reaction of algal organic matter with NaOCl resulted in trihalomethanes (THMs) concentration increase. The oxidation results by NaMnO₄ significantly improved the concentration reduction of THMs and MC-LR. Therefore, this study suggests that NaMnO₄ is effective as a pre-oxidant for reducing algae damage and byproducts in water treatment process.

• 한국환경농학회지
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• 제26권1호
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• pp.7-16
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• 2007

The objective of this research was to review the correlation between microalgae and agricultural water quality. Although microalgae has been considered as an essential factor for control1ing of water ecosystem, little attention has been paid for evaluating of microalgae as an important factor for water quality management. But it can be use to make us know the water pollution state at saprobic system, LTSI (Lake Tropic State Index), DAIpo (Diatom Assemblage Index to Organic Pollution), and AGP (Algal growth potential). In saprobic system, it is used microalgae such as Actinastrum hantzschii var. fluviatile, Asterionella gracillima, Coelastrum microporum, Synedra acus, Dictyosphaerium pulchellum, Micractinium pusillum, Cyclotella meneghiniana, Microcystis aeruginosa, Scenedesmus quadricauda, and Nitzschia palea for assessment water quality. In addition, they have ecologically significant characteristics such as dominant species, cosmopolitan species, redtide causative species etc. Also, microalgae such as Botryococcus braunii, B. sp., Chlorella vulgaris, C. sp., Phormidium sp., Scenedesmus quadricauda, Selenastrum capricornutum, Spirulina maxima, and S. platensis have an effect on improvement of water quality.