• Korean Journal of Ecology and Environment
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• v.34 no.3 s.95
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• pp.199-205
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• 2001

This study was investigated to the assessment of organic pollution using attached diatom assemblages in the Shinchon stream on April, June, September and December 1999. Diatoms were identified total 74 taxa which composed of 68 species, 4 varieties and 2 unidentified species. The Centrales were 5 taxa and Pennales were 69 taxa. Dominant species were Navicula subminuscula, Navicula saprophila and Nitzschia palea which were saprophilous taxa to organic pollution. N. palea was dominant species at st. $1{\sim}3$ on April, June and September and N. subminuscula was recorded as dominant species at st. 4 on June, September and December. N. saprophila was dominated only at station 4 on April. DAIpo values were ranged $0.4{\sim}15.3$ at all stations from April to December and the water qualities were polysaprobic states except to ${\alpha}-mesosaprobic$ state at st. 1 on June. If Navicula sp. was identified as saprophilous taxa, DAIpo value of this station will be 3.5 and water quality of the station will be polysaprobic state. This stream was assessed the water qualities of polysaprobic states.

• Journal of environmental and Sanitary engineering
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• v.19 no.2
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• pp.45-50
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• 2004

To investigate the epilithic diatom community and water quality of the Osan stream, water samples were collected from the eight stations from April to September 2003. Sampling was two times before and after heavy rain. Total 52 diatom were identified and divided into 12 saproxenosus taxa, 6 saprophilous taxa and 34 indifferent taxa, respectively. The DAIpo values higher after heavy rain than before that. According to tolerance degree to the organic water pollution, all sampling stations ranged from $\alpha$-oligosaprobic to $\alpha$-mesosaprobic. Thus, the result indicates that the water quality of Osan stream is gradually improved by heavy rain.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.191-199
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• 2003

This study was conducted to investigate a seasonal variation of phytoplankton communities at 6 stations in the Hantan River from November, 2001 to August, 2002. Electric conductivity gradually increased from the upper reaches to the down reaches. DO differed not much from the upper reaches to down reaches, but it decreased at the station where the pollutants inflowed. T-N and T-P concentrations were high at station 4${\sim}$6. Chlorophyll-a concentration gradually increased at the mid and down reaches. It was high in May but decreased in August by the heavy rains. Phytoplankton communities were identified a total 354 taxa composed of 99 genus, 320species, 19 varieties, 3 forma and 12 unidentified species. There were 135 taxa of Chlorophyceae, 134 taxa of Bacillariophyceae, and the other taxa were Euglenophyceae, Cyanophyceae, Xanthophycaea, Chrysophyceae and Dinophyceae. Standing crops ranged from 8,600 to 337,100 cells/mL and it was lower in August than May by the rains. Dominant species included Achnanthes alteragracillima, Achnanthes convergens, Achnanthes minutissima and Cymbella minuta var. silesiaca which were the saproxenous species at the reaches, and were Cyclotella meneghiniana, Chlamydomonas pseudopertyi and Nitzschia which were saprophilous and eutrophic species at the down reaches. The correlation coefficients between phytoplankton standing crops and EC, BOD and T-N, T-P was 0.68, 0.60, 0.60 and 0.70, respectively. All correlation coefficients between Chlorophyceae and EC, BOD and T-P were higher than 0.6. A. convergens were negative correlations with EC and BOD, but N. palea were positive with EC, BOD, T-N and T-P.

• Journal of Korean Society on Water Environment
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• v.30 no.3
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• pp.283-291
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• 2014

To study the distribution characteristics of diatom communities in relation to the gradient of water quality and land-use, water samples and epilithic diatoms were collected from 90 sites including mainstream and tributaries, in the Geum River System (GRS) during no rainfall, May 2011. Of 239 taxa identified, Achnanthes convergens and Cymbella minuta were dominated over all the sites. Cluster analysis on the GRS divided into three groups. Group 1 (G1) is the mountainous upstream, a relatively good water quality, and mainly consisted of saproxenous species. Group 2 (G2) is the urban sites, polluted (high in electric conductivity, total phosphate and soluble reactive phosphorus), and saproxenous and common species. Group 3 (G3) is the agriculture sites, and polluted (turbidity, total nitrogen, nitrate), and saprophilous species. There were some discrepancies between abiotic and biotic variables in GRS; biologically similar between G1 and G2, but abiotically similar between G2 and G3. These differences may attribute to not only physiological characteristics of diatom cells, but complicate relationships between microhabitat and water quality. Thus, an urgent development of generalized or standardized methods to diminish the differences between epilithic diatom community and environments is advent.

• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.233-239
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• 2008

In order to access the water quality using epilithic diatom assemblage index to organic water pollution (DAIpo) in the lower part of the Han River, the diatom samples were collected biweekly at 2 stations by means of artificial substrates of ceramic tiles from February, 2004 to February, 2005. A total of 60 taxa, representing 18 genera 51 species, 7 varieties and 2 forms, of diatoms were identified in the present study. Dominant percentages of Aulacoseria granulata and Melosira varians (Indifferent taxa) were 22.76$\sim$30.30% and 17.44$\sim$34.78%, respectively, and Nitzschia palea (Saprophilous taxa) were 15.00$\sim$31.76% at St. 1. In St. 2, the percentages of dominant species, N. palea, were 19.86$\sim$58.20%. Average DAIpo index was 40.6 in St. 1 and 32.1 in St. 2, and the saprobic level was shown $\beta$-mesosaprobic in the lower part of the Han River. It is suggested that epilithic diatoms as bioindicators and a DAIpo index indicate useful for analy-zing assessment of the water quality.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.232-241
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• 2010

Epilithic diatom communities and water quality were monitored to evaluate the ecological impact of the inflow of Wonju-stream passing through the urban area in the Seom River Watershed. We selected the 14 sampling stations (5 main stream sites and 9 tributary sites), and collected diatom and water samples between October 2007 and September 2008, on the seasonal basis. The results indicate that most water quality parameters showed the site-specific patterns over the study, except for water temperature and dissolved oxygen. The levels of water quality parameters were highest at the site of Wonju stream, whereas the lowest in the upstream sites, and intermediate or gradually decreased in the downstream sites of the Seom river. One species, Achnanthes convergens, showed the highest biomass and frequency over the sites, while three saprophilous species-Navicula goeppertiana, Navicula subminuscula, Nitzschia palea were appeared only in Wonju Stream and other polluted sites. According to trophic diatom index (TDI) values, which were highly correlated with nutrients and EC, the study sites were classified into three classes: upstream and tributary (Class A and B), Wonju Stream (Class D), and mixed zone and downstream (Class C). A cluster analysis supported the result of TDI classification. Therefore, Wonju-stream located in populated urban area exerted the adverse ecological effects on the epilithic diatom community and water quality of the lower Seom River System, although its severity gradually decreased downstream.

• Korean Journal of Ecology and Environment
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• v.48 no.2
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• pp.115-121
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• 2015

In order to assess the water quality of Kumho river using Diatom Assemblage Index to organic water pollution (DAIpo) and to campare from the previous water quality, 5 sites in Kumho river were selected and assessed total of 6 times, every April and September from April 2010 to September 2012. As a result, 116 taxa were found in 2 Order, 3 Suborder, 7 Families, 26 Genera, 103 species and 13 varieties. Saprophilous species of 10 dominant species including Achnanthes minutissima, were increased as going to downstream sites. Correlation coefficients (r) between epilithic diatom communities and physicochemical factors were from - 0.62 to 0.71. Correlation coefficients (r) between TN and diatom indices (DAIpo, TDI) were 0.57 and 0.65, respectively. Therefore, epilithic diatom communities were greatly influenced by TN. The Correlation between DAIpo and TDI measured to be high in correlation coefficient (r=0.62) from the result of correlation analysis. Mean of DAIpo values ranged between 37.24~74.98 and decreased as going to downstream sites. Saprobic level was estimated as ${\beta}$-oligosaprobic at st. 1, ${\alpha}$-oligosaprobic at st. 2 and ${\beta}$-mesosaprobic at st. 3. But st. 4 and 5 which were ${\alpha}$-mesosaprobic and polysaprobic in the previous results, were improved as ${\beta}$-mesosaprobic. The RPId, general assessment of the water quality using DAIpo, was 52.27, which means the water quality of Kumho river was middle level.

• Korean Journal of Ecology and Environment
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• v.40 no.3
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• pp.468-480
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• 2007

The urbanization is altering the hydrology, water quality, channel form of waterway and changing the composition of biological communities in the aquatic ecosystem. Recently, towns grew bigger by the drift of large numbers of people and the medium and small leather and dyeing industries around the Pocheon and Youngpyeong streams. The discharges of sewage were increased by them. The UII (urban intensity index) was 85 (st. P-3) and 91 (st. P-6) in the Pocheon stream and about 20 in the Youngpyeong stream. A total 141 taxa of epilithic diatoms which were composed of 2 order, 8 family, 30 genera. Dominant species were Navicula saprophila, N. subminuscula, Nitzschia palea, Gomphonema pseudoaugur in the Pocheon stream and Achnanthes alteragracillima, A. convergens, A. minutissima, N. minima, N. fonticola, N. frustulum and Cymbella minuta var. silesiaca in the Youngpyeong stream. It Showed the different composition of dominant species by the urbanization near two streams. In the relationships between UII and environmental factors such as EC, BOD, COD, TN, TP and DAIpo, UII showed the high relations $(r^2>0.8)$. It was the difference of organic pollution according to urbanization. It therefore, was higher the relative abundance and more the numbers of saprophilous taxa in the Pocheon stream than the Youngpyeong stream. The water quality of two streams by biological indicators(DAIpo) was polysaprobic state(st. P-3, P-4, P-5) in the Pocheon stream and was oligosaprobic (Y-1), mesosaprobic (Y-2, 3) and polysaprobic state (Y-4) in the Youngpyeong stream during the investigation periods.

• Korean Journal of Environmental Biology
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• v.25 no.1
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• pp.16-26
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• 2007

To study the succession of epilithic diatoms on the artificial substrate, we investigated environmental factors and the diatom assemblages biweekly from Mar. 2004 to Feb. 2005 at 2 stations in the lower part of the Han River. A total of 60 taxa, representing 2 orders, 3 suborders, 8 families, 17 genera, 51 species, 7 varieties and 2 forms were identified, and mean number of species were 19 species in spring, 20 in summer, 22 in autumn and 22 in winter. Standing crops of epilithic diatoms varied extensively by months and stations; mean values of those were $3.2{\times}10^4$ cells $cm^{-2}$ in spring, $1.9{\times}10^4$ in summer, $1.7{\times}10^4$ in autumn and $1.8{\times}10^5$ in winter. Chlorophyll a concentrations were also similarly showed as variations of the diatom assemblages. Succession of the diatoms in St. 1 was as follows; Melosira varians, Fragilaria capucina, Cyclotella comta, Nitzschia palea in spring, Fragilaria capucina in summer, Aulacoseira granulata var. angustissima in autumn, Aulacoseira granulata var. angustissima and Melosira varians, Cymbella minuta in winter. In station 2, Aulacoseira granulata and Nitzschia palea dominated in spring as a pioneer in early stage of succession, Fragilaria capucina in summer, and Nitzschia palea in winter. According to Canonical Correspondence Analysis (CCA), there showed similar to that of succession of epilithic diatoms within St. 1 and St. 2, and they were not changed by stations but seasons. Nitzschia palea belonged to saprophilous taxa correlated with nitrogen sources and suspended solids. Meanwhile, Fragilaria capucina and Cymbella minuta included in xenosaprobic taxa show correlation with DO and pH. Eurysaprobic taxa correlated with all environmental factors.

• Korean Journal of Ecology and Environment
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• v.48 no.3
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• pp.153-167
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• 2015

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.