• 환경생물
• /
• 제42권2호
• /
• pp.158-171
• /
• 2024

Diatoms, which are reported to have over 18,000 species worldwide and approximately 2,400 species in Korea, can be found in various environments including freshwater, seawater, and wetlands. They are particularly valuable for understanding global environmental changes throughout history due to their ability to maintain their shape for extended periods of time. Instead of collecting floating diatoms using nets, low-layer substrates such as gravel and leaves, as well as sedimentary surface layers, were gathered in order to identify attached diatom species. This is because attached diatoms demonstrate higher species diversity compared to floating diatoms. In this study, seven previously unrecorded diatoms were discovered in various domestic freshwater environments. Two species were found in reservoirs (Eunotia yanomami, Gomphonella pseudookunoi), two in parasitic cones (Eunotia karveerensis, Luticola minor), two in rivers (Cavinula maculata and Prestauroneis integra), and one (Surirella brebissonii var. kuetzingii) in a lagoon. The shapes, structures, and morphological characteristics of each diatom were identified using electron microscopy.

• 한국제4기학회지
• /
• 제31권2호
• /
• pp.1-12
• /
• 2017

김제시 부량면 용성리 일대 유적 발굴 지역의 트렌치 단면으로부터 총 23개의 시료를 채취하여 규조를 분석하였다. 총 32속 61종의 규조를 감정하였으며, 종 다양성과 개체 수는 매우 적었다. 각 층준의 군집 조성과 규조 절대 개체 수 및 환경지시종의 분포에 의해서 3개의 군집대를 설정하였다. 규조분대 I에서는 해수종이 주로 산출되었으며, 인접한 지역에서는 해수종의 산출이 보고되지 않았기 때문에 이는 해수유입에 대한 귀중한 자료가 된다. 규조분대 II에서는 기수종과 담수종의 산출이 풍부하여 담수의 유입으로 인한 기수 환경이었음을 알려준다. 규조분대 III에서는 담수종의 산출이 많고, 그 중 Eunotia속에 포함되는 종들이 주로 산출되는 것으로 보아 담수의 유입이 있는 습윤한 토양 환경에서 퇴적되었다.

• 환경생물
• /
• 제36권3호
• /
• pp.241-251
• /
• 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
• /
• 제19권2호
• /
• pp.23-29
• /
• 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
• /
• 제10권1호
• /
• pp.46-56
• /
• 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
• /
• 제37권2호통권107호
• /
• pp.236-240
• /
• 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
• /
• 제12권4호
• /
• pp.313-320
• /
• 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
• /
• 제28권11호
• /
• pp.1005-1017
• /
• 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
• /
• 제53권4호
• /
• pp.597-605
• /
• 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
• /
• 제26권3호
• /
• pp.238-247
• /
• 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.