• 환경생물
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• 제36권3호
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• pp.241-251
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• 2018

To find unrecorded diatom species, random materials were collected from the freshwater, brackish water, and coastal waters. Benthic and periphytic diatoms were sampled from twelve localities. Thirteen species belonging to eight genera are newly added to the national flora of diatom. In the intertidal areas, the five species are new to Korea, Anaulus minutus Grunow, Anaulus simonsenii Witkowski & Metzeltin, Eunotogramma laeve Grunow, Eunotogramma productum Grunow, and Nitzschia subcapitellata Hustedt. The following two species are new from brackish waters, Chamaepinnularia krookiformis (Krammer) Lange-Bertalot & Krammer and Cymatoneis ovalis Heiden. The following four species are new from mountain peatlands, Geissleria ignota (Krasske) Lange-Bertlaot & Metzeltin, Chamaepinnularia hassiaca (Krasske) Cantonati & Lange-Bertalot, Chamaepinnularia mediocris (Krasske) Lange-Bertalot and Pinnularia linearidivergens Kulikovskiy, Lange-Bertalot & Metzeltin. The following two species are new from river or streams, Cymbella hustedtii var. compacta Krammer and Cymbella stigmaphora ${\emptyset}strup$.

• 환경위생공학
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• 제19권2호
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• pp.23-29
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• 2004

An algicidal effect of endemic algicidal bacterium (Pseudomonas putida) and rotifer zooplankton (Brachionus calyciflorus) on diatom Stephanodiscus hantzschii were examined in the filtered water, and were compared with those of bacterium plus ciliate. Bacteria removed as 80% of the diatom within 3.5 days, while ciliate and zooplankton suppressed 57% and 40% of diatom during the same period, respectively. Mixed treatment of bacteria plus ciliate removed as 54% of diatoms, while that of bacteria plus zooplankton decreased as 85%. Although single bacteria and mixed treatment of bacteria plus zooplankton quickly decreased the diatom in the initial of experiment, bacteria plus ciliate perfectly removed the diatom in culture flask within 5.5 days of the study. On the other hand, other single and mixed treatments did not clear the diatom during the same period, and over 10% of them still remain in culture flask. Predator biomass in the presence of algicidal bacteria showed the growth patterns; zooplankton gradually decreased, and ciliate sustained over 0.5 cells/ml. These results indicated that the addition of ciliate to the algicidal bacterium in controlling the diatom Stephanodiscus hantzschii is more effective than that of zooplankton. Therefore, this synergistic interaction relationship between the bacterium and ciliate play an important role in the bio-manipulation using bio-agents to control the diatomal bloom in freshwater lakes and streams.

• Journal of Species Research
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• 제10권1호
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• pp.46-56
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• 2021

Diatoms have been used in examining water quality and environmental change in freshwater systems. Here, we analyzed molecular profiling of seasonal diatoms in the Han River, Korea, using the hypervariable region of 18S V1-V3 rRNA and pyrosequencing. Physicochemical data, such as temperature, DO, pH, and nutrients showed the typical seasonal pattern in a temperate region. In addition, cell counts and chlorophyll-a, were recorded at high levels in spring compared to other seasons, due to the diatom bloom. Metagenomic analysis showed a seasonal variation in the phytoplankton community composition, with diatoms as the most frequently detected in spring (83.8%) and winter (69.7%). Overall, diatom genera such as Stephanodiscus, Navicula, Cyclotella, and Discostella were the most frequent in the samples. However, a large number of unknown Thalassiosirales diatoms were found in spring (35.5%) and winter (36.3%). Our molecular profiling revealed a high number of diatom taxa compared to morphological observation. This is the first study of diatoms in the Han River using molecular approaches, providing a valuable reference for future study on diatoms-basis environmental molecular monitoring and ecology.

• 생태와환경
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• 제37권2호통권107호
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• pp.236-240
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• 2004

국내에서 저온기에 하천 및 하천형 호수에서 대발생하는 소형원반 규조 stephanodiscus hantzschii 제어를 위하여 팔당호 상류인 경안천 수역에서 세균 Pseudomonas putida 및 섬모충 Stentor roeseli 를 각각 분리하고, 이들의 단일 및 혼합적용시 조류제어효과를 조사하였다. 세균단일처리군에서는 접종 7일만에 98%이상의 규조를 제거한 반면, 섬모충 단일 처리군에서는 약 80%정포를 제어하였다. 두 생물제재를 혼합적용한 경우, 배양 5일만에 배양계내에서 더 이상 규조가 관찰되지 않았다. 이 결과는 살조세균과 섬모충의 두 생물재제 혼합적용이 규조 Stephanodiscus hantzschii 대발생을 제어하는데 매우 효과적이며 현장적용 가능성이 높다는 것을 제시한다.

• Journal of Species Research
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• 제12권4호
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• pp.313-320
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• 2023

Diatoms are unicellular eukaryotic microalgae, and they are highly diversified in aquatic environments. We describe an unrecorded diatom species Fragilaria saxoplanctonica Lange-Bertalot & Ulrich (Bacillariophyceae) collected from Paldang Reservoir, Korea, on 4 April 2022. The valve was needle shaped and narrowly rectangular, its ends were rounded, and no spines were found on the outline of their valves. The valve was 67.2-70.2㎛ in length and 1.4-2.9㎛ in width. The ratio of width-to-length was 1 : 23.2-50.1. The pattern of striation was alternate or opposite, and the number of striae in 10㎛ was 24-26. Molecular comparisons of the 18S rDNA and rbcL sequences showed that it belonged to the genus Fragilaria. These morphological and phylogenetic results confirmed that our species was F. saxoplanctonica, and it was the first record in Korea.

• 한국환경과학회지
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• 제28권11호
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• pp.1005-1017
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• 2019

Environmental factors and changes in phytoplankton community structure before (August 5, 2017), during (August 18 and 25) and after (August 30 and September 15) freshwater input were analyzed to investigate the effects of freshwater input from Ganwol and Bunam lakes located in the upper part of Cheonsu Bay. Due to the large amount of freshwater input in the Cheonsu Bay, the surface salinity of the bay decreased by more than 8 psu, and the thermocline existing in the bay during August weakened. In addition, hypoxic phenomena occurred temporarily in the bay as the low oxygen water mass from the freshwater lakes flowed into the bay, and chemical oxygen demand, nutrients, and N/P increased with freshwater inflow. The density of phytoplankton during the freshwater inflow increased owing to their input from the freshwater lakes. Diatom species (Eucampia zodiacus) dominated the phytoplankton community in the bay before freshwater input; nanoflagellates, chlorophyta, cyanobacteria, and diatoms (Pseudonitzschia delicatissima, Chateocceros spp.) entered during freshwater input; and after freshwater inflow ended, diatoms (Chateocceros spp.) again became predominant indicating a return to previous conditions. The amount of phytoplankton standing crops increased sharply due to the inflow of freshwater species into the bay on the second day of discharge compared to before freshwater input; pre-discharge conditions were restored at most stations except at some sites close to the Bunam Lake three days after discharge. Therefore, the large amount of freshwater flowing into the bay affects not only the geochemical circulation in the bay but also the phytoplankton community structure. In particular, the high concentration of nutrients in the freshwater lake affect the marine ecosystem of the bay during August.

• 한국수산과학회지
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• 제53권4호
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• pp.597-605
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• 2020

The diatom Melosira nummuloides is a microalga that is widely distributed in freshwater and seawater is used is used in the production of silicon and fucoxanthin. The objective of this experimental study was to determine the effects of diatom powder on the physiology of olive flounder Paralichthys olivaceus. In four feeding groups consuming 0%, 1%, 2% and 3% diatom powder. After 8 weeks of feeding, we investigated P. olivaceus growth rate, feed efficiency rate, survival rate, anti-oxidant enzyme rate, non-specific immune activity and immune gene expression. The rates of growth rate, feed efficiency rate and survival were significantly higher for olive flounder in all diatom groups than in the control. The results for anti-oxidant enzyme, superoxide dismutase and catalase showed no significance, but glutathione was significant, depending on the concentration of diatom addition. The galectin and lysozymes of immune genes were increased in the control group. Galectin and lysozymes were thought to have increased due to infections by from pathogens during the experiment period. These results suggest that the addition of diatoms to olive flounder diets is effective in enhancing growth rate and innate immunity.

• 한국해양학회지:바다
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• 제26권3호
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• pp.238-247
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• 2021

돌말류는 미세조류의 일종으로서 담수 및 해양의 여러 다양한 환경의 수생태계에서 가장 중요한 1차 생산자 중 하나이다. 환경을 대표할 수 있는 생물 지표로서 널리 이용되고 있으며, 여러 지역에서 서로 다른 과학자들에 의한 연구 결과들이 과학적 통일성과 객관성을 갖추도록 하기 위해서는 돌말류 분석 자료의 정도 관리가 매우 중요하다. 현재 돌말류 분석은 형태적인 특징으로 분류하는 형태 기반의 분석과 DNA 서열로 종을 식별하는 DNA 바코드 분석이 사용되고 있다. 형태학 기반의 돌말류 분류는 분석 자료를 해석하는 분류학자들 간의 일관된 종 식별이 요구되는 한편 분자 분류 기반의 돌말류 분류는 신뢰성 있는 참조데이터가 필수적이다. 본 논문에서는 돌말류 분석 자료 정도관리의 국내외 현황을 우선 살펴보았으며, 그에 기반하여 국내 돌말류 분석 자료의 정도 관리에 대한 의견을 또한 제안하였다.

• 한국해양학회지:바다
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• 제10권3호
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• pp.154-163
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• 2005

1988년에 완공하여 1994년 8월부터 수문을 작동한 금강 하구언으로 인해 금강 하구역 환경은 크게 변하였다. 수문을 통해 담수를 불규칙하게 방류하면, 극심한 염분 저하와 함께 수중 무기영양염 농도가 급변한다. 이와 같이 환경 스트레스가 큰 금강 하구 내측에서 춘계 식물플랑크톤 군집의 단주기 변동을 연구하기 위하여, 2004년 2월 중순부터 4개월 동안 2개의 고정점에서 약 2일 간격으로 고조 때에 현장조사와 시료채취를 실시하였다. 하구언에 근접한 정점에서는 정점2(도선장 부근 정점)에 비해 염분 측정치의 변동계수가 2배에 이르러, 정점1에서 시간에 따른 염분의 변동이 극심함을 반증하였다. 용존 무기영양염 가운데, 질소계 영양염($NO_3^-,\;NO_2^-$ 및 $NH_4^+$)의 농도가 정점2에 비해 정점1에서 뚜렷이 높게 나타나, 수문 작동에 따라 그 농도가 부정기적으로 급변할 수 있는 환경임을 확인하였다. 식물플랑크톤 군집을 구성하는 주요 분류군은 규조류로서 출현종의 수나 생물량 모두 최고치를 기록하였다. 이 가운데 단독성 중심 규조 Cyolotella meneghiniana와 사슬형 중심 규조 Skeletonema costatum은 조사기간 전반부에 차례대로 5-6주 동안씩(천이 구간 I 및 II)절대 우점하여, 수온 $10^{\circ}C$의 시점을 중심으로 뚜렷한 천이현상을 보여 주었다. 천이구간 III(4월 중순-5월 말)은 대량 방류된 담수와 함께 하구역에 유입된 담수 녹조종인 남세균 Aphanizomenon flos-aquae와 Phormidium sp. 등이 매우 높은 구성비를 나타낸 시기이다. 이 기간에는 극저염-고염의 극심한 변동으로 인하여 낮은 수준의 생물량을 기록한 규조 Cyclotella meneghiniana와 Skeletonema costatum 외에는 담수종들이 전적으로 우점하였다. 천이구간 IV에서는 수온이 $18^{\circ}C$ 이상으로 상승하면서, 규조 Guinardia delicatuia가 단일 시료 내 최고 우점도 $75^{\circ}C$를 기록하며 약 일주일간 우점하였다. 즉, 조사기간 중에는 수온 $18^{\circ}C$ 미만의 극심한 염분 변동기(천이구간 III)를 제외한, 전 기간 중에 규조가 절대 우점하며 춘계 식물플랑크톤 우점종의 천이를 주도하였다. 천이구간 III에서도, 만약 담수방류의 규모와 빈도를 적절히 조절하였더라면, 주요 우점종이 담수 남세균이 아닌 하구성 규조로 바뀔 수도 있었을 것이다. 본 연구에 적용한 격일간 현장조사는 불규칙한 담수방류가 불가피한 반일주조 하의 하구역 환경에서 식물플랑크톤 종의 천이현상을 규명하기 위한 최소한의 필요조건으로 판단된다.

• 해양환경안전학회지
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• 제20권3호
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• pp.270-276
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• 2014

Seasonal characteristics of water and sediment qualities and potential effects of the freshwater discharge from a small tide embankment interior in a coastal area in Goheung county were investigated from May to September in 2012. Chemical oxygen demand values (COD) were mostly higher than 2 mg/L in summer ebb tide, which exceed the standard value of water quality criteria II of acceptable level for aquaculture activities. Nitrogen and phosphorus were found as the limiting nutrients for algae growth in summer and fall and in spring, respectively. Nitrogen was the limiting nutrient for diatom growth in the whole studied period. The sudden high values of COD, ammonia, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) were found in water sample collected from station 5 which located in front of the tide embankment sluice gate during spring ebb tide. The freshwater discharge form the tide embankment interior maybe affected the survey areas during a short time interval. Mean values of eutrophication index of the surveyed coastal region in spring, summer and fall were all bigger than 1. Water quality was mostly considered at level II which acceptable for aquaculture activities. Sediment quality in this study was generally in the range of standard for fisheries environment.