Benthic attached diatoms (BADs), a major primary producer in lotic stream and river ecosystems are micro-sized organisms and require a highly magnified microscopic technique in the observation work. Thus, it is often not easy to ensure accuracy and precision in both qualitative and quantitative analyses. This study proposed a new technique applicable to improve quality control of aquatic ecosystem monitoring and assessment using BADs. In order to meet the purpose of quality control, we developed a permanent mounting slide technique which can be used for both qualitative and quantitative analyses simultaneously. We designed specimens with the combination of grid on both cover and slide glasses and compared their efficiency. As a result of observation and counting of BADs, the slide glass designed with the color-lined grid showed the highest efficiency compared to other test conditions. We expect that the method developed in this study could be effectively used to analyze BADs and contributed to improve the quality control in aquatic ecosystem health monitoring and assessment.

The Bayesian algorithm model is a model algorithm that calculates probabilities based on input data and is mainly used for complex disasters, water quality management, the ecological structure between living things or living-non-living factors. In this study, we analyzed the main factors affected Korean Estuary Trophic Diatom Index (KETDI) change based on the Bayesian network analysis using the diatom community and physicochemical factors in the domestic estuarine aquatic ecosystem. For Bayesian analysis, estuarine diatom habitat data and estuarine aquatic diatom health (2008~2019) data were used. Data were classified into habitat, physical, chemical, and biological factors. Each data was input to the Bayesian network model (GeNIE model) and performed estuary aquatic network analysis along with the nationwide and each coast. From 2008 to 2019, a total of 625 taxa of diatoms were identified, consisting of 2 orders, 5 suborders, 18 families, 141 genera, 595 species, 29 varieties, and 1 species. Nitzschia inconspicua had the highest cumulative cell density, followed by Nitzschia palea, Pseudostaurosira elliptica and Achnanthidium minutissimum. As a result of analyzing the ecological network of diatom health assessment in the estuary ecosystem using the Bayesian network model, the biological factor was the most sensitive factor influencing the health assessment score was. In contrast, the habitat and physicochemical factors had relatively low sensitivity. The most sensitive taxa of diatoms to the assessment of estuarine aquatic health were Nitzschia inconspicua, N. fonticola, Achnanthes convergens, and Pseudostaurosira elliptica. In addition, the ratio of industrial area and cattle shed near the habitat was sensitively linked to the health assessment. The major taxa sensitive to diatom health evaluation differed according to coast. Bayesian network analysis was useful to identify major variables including diatom taxa affecting aquatic health even in complex ecological structures such as estuary ecosystems. In addition, it is possible to identify the restoration target accurately when restoring the consequently damaged estuary aquatic ecosystem.

Upo Wetland is the largest riverine wetland in Korea which has been inscribed on the Ramsar List of Wetlands of International Importance in 1998. In this study, sedimentological study was carried out in order to understand the environmental changes in Upo Wetland during the Holocene. The drilling work for recovering the Quaternary sediments was conducted on the inner part (UPW17-01, UPW17-02, and UPW17-03) and the outer part (UPL17-01, UPL17-02) of the Upo Wetland. The recovered sediments are commonly characterized by gravel-dominated deposits in the lower part and silty clay-dominated deposits in the middle to upper parts respectively, which are seemed to be changed from fluvial to palustrine/lacustrine environments around 4,000 cal yr BP. In order to establish the Holocene diatoms distribution from Upo Wetland, we identified 63 diatom taxa. Of these, 14 species were new records for Korea: Gomphonema consector, Gomphonema jadwigiae, Hantzschia abundans, Luticola pseudomurrayi, Luticola spauldingiae, Neidium suboblongum, Ninastrelnikovia gibbosa, Oricymba rhynchocephala, Pinnularia borealis var. lanceolata, Pinnularia latarea, Pinnularia paliobducta, Pinnularia saprophila, Sellaphora laevissima, Stauroneis pseudoschimanskii. All identified diatom species are illustrated by high-quality scanning electron microscopic and light microscopic microphotographs. The ecological habitat for all taxa are presented.

본 연구는 한국 남서해안 갯벌 중 유부도, 곰소만, 임자도, 여자만 갯벌의 저서돌말류 종조성 및 생물량을 알아보기 위해 2016년 8월과 9월에 현장조사를 실시하였다. 유부도 갯벌에서 저서돌말류는 48속 181종, 곰소만 갯벌에서 51속 194종, 임자도 갯벌에서 64속 224종, 여자만 갯벌에서 56속 188종이 출현하였으며, 총 70속 274종이 출현하였다. 분류군 가운데 중심돌말목보다 우상돌말목이 다양하게 출현하였고 우점종은 중심돌말목의 Paralia sulcata와 Navicula spp.였다. 유부도 갯벌의 생물량은 정점별로 18.8~136.1 mg m-2, 곰소만 갯벌 31.9~215.7 mg m-2, 임자도 갯벌 2.9~120.2 mg m-2, 여자만 갯벌 10.1~147.7 mg m-2, 4개 지역의 총 생물량 범위는 2.9~215.7 mg m-2였다. 엽록소 a의 분해 산물인 phaeopigment 농도로는 유부도 갯벌에서 1.7~470.8 mg m-2, 곰소만 갯벌에서 52.3~277.2 mg m-2, 임자도 갯벌에서 0.6~78.9 mg m-2, 여자만 갯벌에서 39.1~346.3 mg m-2으로 나타났다. 조사 대상지역의 종 다양성과 생물량은 높은 경향을 나타내었다. 한국의 남서해안은 다양한 저서돌말류가 서식하며 엽록소 a의 높은 농도는 일차생산력을 결정하는 주요인자다.

With land-use (cover) and water quality, the distributional characteristics of epilithic diatom communities were studied with 193 samples from estuaries of Korean peninsula between 2015 and 2016. Of total 394 taxa classified, Nitzschia perminuta (19.6%) and N. inconspicua (14.0%) were the 1st and 2nd dominant species. Using a cluster analysis, the epilithic diatom communities of Korean estuaries were divided into four groups (G1-G4). Ecological characteristics of each group were followed: G1 was located in estuaries of the East Sea, and characterized by high forest land-use and high DO and low nutrients; G2 was the eastern part of the South Sea, and characterized by low turbidity and nutrients; G3 was the western part of the South Sea, and characterized by high agriculture, low electric conductivity and low salinity; G4 was the Yellow Sea, and characterized by high nutrients. The environmental factors having significant correlation with diatom distributions were as follows: TN to G1, turbidity to G2, agriculture to G3, and TP to G4. Moreover, the important factors affecting the occurrence of indicator species were forest land-use for Fragilaria construens var. venter in G1, turbidity for Rhoicosphenia abbreviata in G2, urban land- use and total phosphorus (TP) for Bacillaria paradoxa and Hantzschia amphioxys of G3, and TP and turbidity for N. ovalis and Stephanodiscus invistatus of G4. These results collectively indicate that the distribution of epilithic diatom communities in Korean peninsula was largely effected by water quality and land cover/use.

In order to understand the relationship between the distribution of epilithic diatoms and the habitual environments, land-use, water qualities, and epilithic diatoms were studied at 141 sampling sites in the midwestern stream of Korean peninsula (Geum river, Mangyeong river, Dongjin river, and Sapgyo river). The total 183 diatom taxa was appeared in the study, while the dominant species were found to be Nitzschia palea (10.9%) and Achnanthes convergens (8.4%). Based on the abundance of epilithic diatoms, a cluster analysis results indicate that the sampling sites divided the sampling sites into 4 groups (G) at the 25% level. In term of geographic and aquatic environments, G-I and -II accounted for the upper and mid streams of the Geum river, and had large forest areas and good in water quality. G-III accounted for farmland and urban, and high concentration nutrient levels (TN and TP) and electric conductivity. G-IV accounted for mostly farmland, and high levels in turbidity, BOD, nutrient and electric conductivity. CCA results showed that the saproxenous taxa Meridion circulare was the indicator species of G-I, which strongly influenced by altitude and forests. In G-II, the indifferent taxa Navicula cryptocephala was influenced by Chl-a, AFDM, and DO. In G-III and -IV, the indifferent taxa Fragilaria elliptica and saprophilous taxa Aulacoseira ambigua were influenced by electric conductivity, turbidity, and nutrient counts. Meanwhile, random forest results showed that the predicting factor of indicator species appearance in G-I, -II, and -III was found to be electric conductivity whereas in G-IV it was found to be turbidity. Collectively, the distribution of diatoms in the midwestern of Korean peninsula was found to depend more on the land-use and its subsequent water qualities than the inherent characteristics of the aquatic environment.

본 연구는 하천에서 가뭄으로 인해 나타나는 갈수현상 을 단기간의 유량의 감소로 모사하여 수질 및 부착돌말류 군집에 미치는 생태학적 영향을 인공수로에서 분석하였 다. 아크릴로 제작한 실내 인공수로에 부착돌말 인공기질 로는 슬라이드글라스를 설치하고, 부영양 저수지의 표층 수를 유입시켜 실험수로 이용하였다. 실험기간 중 부착돌 말 군체형성기 동안 모든 실험군의 유량은 6 L min-1, 이 후 유량감소기 동안 각 실험군의 유량은 NDF(No depletion of flow rate (Control): 6 L min-1), LDF (Low depletion of flow rate: 3 L min-1), 그리고 HDF (High depletion of flow rate: 1 L min-1)로 설정하였다. 유량감소의 영향을 비교하기 위하여 16일간의 실험기간 동안 유입수와 배출 수의 수온, 전기전도도, 용존산소, pH, 탁도, 부유물질, 영 양염 및 Chl-a 농도를 분석하였으며, 또한 부착기질의 Chl-a와 AFDM(ash free dry matter), 그리고 부착돌말류 의 조성과 세포밀도를 1일 간격으로 분석하였다. 광도는 처리 유량이 적어질수록 유의하게 증가했다(F=229.5, p= 0.000). NH4-N는 NDF보다 HDF에서 현저하게 높은 농 도를 유지하였다. 유입수의 SS 농도(100%) 대비 배출수의 SS 농도는 HDF에서 88%로 감소하였으며 LDF (97%)와 NDF (99%)에 비하여 높은 감소율을 보였다. 기질의 Chla는 NDF에 비하여 유량감소 처리군에서 약 2배 이상 유의하게 증가하였다(F=8.399, p=0.001). 또한 기질의 AFDM과 부착돌말류 총밀도는 NDF에 비하여 두 처리군 에서 유의하게 증가하였다(F=9.390, p=0.001; F=6.088, p=0.007). 실험기간 동안 대조군과 처리군 모두에서 Aulacoseira ambigua, Achnanthes minutissima, Aulacoseira granulata 등 총 3종의 부착규조류가 총 밀도의 10% 이 상을 보인 우점종으로 나타났고, 제1 우점종인 A. ambigua 는 LDF에서 가장 높은 밀도를 보였으며 HDF, NDF순 으로 생물량이 낮았다(F=8.551, p=0.001). 본 연구 결과, 인공 하천생태계에서 가뭄(갈수) 효과는 수질과 부착돌말 류 현존량에 유의한 변화를 야기하였으며, 특히 부착돌말 류 현존량이 유의하게 증가하였다. 이는 실제 하천에서 가뭄에 의한 생태계의 변화를 이해하는데 유용한 기초자 료를 제공할 것으로 사료된다.

본 연구는 한강하류역에서 2개 정점을 선정하여 2004년 2월부터 2005년 2월까지 갈수기에 격주 간격으로 인공기질을 이용하여 부착돌말류에 의한 수질평가를 수행하였다. 조사기간 중 출현한 부착돌말류는 총 60분류군으로 2목 3아목 8과 18속 51종 7변종 2품종으로 구성되어 있었다. 정점별 우점종은 정점 1에서 광적응성 종인 A. granulata (22.76~30.30%), M. varians (17.44~34.78%)와 호오염성

본 연구는 한강하류역에서 인공기질을 이용하여 부착돌말류의 계절적 천이를 규명하고, 환경요인과 부착돌말류의 관련성을 통계학적으로 규명하기 위하여, 2004년 2월부터 2005년 2월까지 1년간 매 격주간격으로 2개 정점에서 환경요인과 부착돌말류를 조사하였다. 조사 결과 수온은 전형적인 온대지방의 기후를 나타냈고, pH는 갈수기인 겨울철에 상대적으로 높게 나타났다. 전기전도도, 질소, 인 등은 정점 간 차이를 보여 정점 2에서 높은 값을 나타냈으며, 규산염