• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.606-614
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• 2009

To evaluate the biological water quality, diatom-based biological indices (DAIpo and TDI) were examined in the Sum-River and the Dal-stream. Having BOD concentrations below $2mg{\cdot}L^{-1}$ in most sites, water quality of both rivers was good. The DAIpo and TDI values ranged from 29.8 to 91.4 and from 38.7 to 93.0 respectively. From the biological water quality assessment, DAIpo and TDI for both rivers displayed fair to fairly poor water quality levels. However, the two indices showed more polluted conditions than expected from the BOD vlaues. In addition, DAIpo, having wider range of differences, appears to be more sensitive to the change in water quality when compared to TDI values. Statistical analysis using principal component analysis showed that Nitzschia palea and Diatoma vulgare might not be the appropriate indicators due to their low correlations with other indicators.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.784-795
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• 2006

The purpose of this study was to assess biological river water quality by using epilithic diatoms at 40 selected sites in Geum, Youngsan, and Seomjin River systems. The sampling and analyses were performed during three seasons including January, April and June in 2005. Various water quality parameters also were analyzed. We attempted to classify the water quality condition by epilithic diatom indices (DAIpo and TDI) with the results of corresponding analyses of various chemical water quality parameters. A five class system was delivered to describe the water quality condition ranged from "very good" to "very poor." We also proposed a way of classifying water quality condition by combining two diatom indices of DAIpo and TDI. Our results showed that biomass of epilithic diatoms varied not only seasonally but spatially; it was not likely that winter diatoms represent average water quality condition, due to high concentration of nutrients. Water quality status assessed by diatom indices was generally worse than that assessed by BOD, indicating that BOD standard likely underestimates the biological condition of the water body. Importantly, nutrient-based diatom index (TDI) generally overestimated organic matter-based index (DAIpo) at most study sites, indicating that diatoms in studied rivers were likely more affected by nutrients than organic matter. Thus, management strategy to improve river water quality in Korea is suggested to emphasize more on the nutrients than organic matters.

• Korean Journal of Ecology and Environment
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• v.52 no.1
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• pp.1-8
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• 2019

River water quality and organisms have a very close relationship with the human living environment and health, so it is very important to ensure and maintain the ecological integrity of the aquatic ecosystem. In that sense, benthic diatoms have relatively little mobility, can explain the effects of long-term exposed pollution sources, and are very suitable indicator organisms for river ecosystem evaluation. Diatom ecologists have been developed various diatom indices to assess water quality and stream ecosystem over the world. However, they so far have insufficient identification of taxa, are strongly regional, and are difficult to apply as they are domestically. Unfortunately, there has not been developed an independent diatom index suitable for the Korean stream. Therefore, management of water quality and aquatic ecosystem suitable for domestic rivers can be made, and development or improvement of comprehensive multivariate diatom index for the integrated assessment of water quality and aquatic ecosystem is urgently needed.

• Korean Journal of Environmental Biology
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• v.29 no.3
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• pp.180-194
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• 2011

In this study, We were investigated the interrelationships between epilithic diatom communities and physico-chemical factors at Banbyeon stream, Gilan stream and Nakdong river in the Lake Imha basin from September 2008 to June 2009. Epilithic diatom communities were identified a total 120 taxa which were composed to 2 Orders, 3 Suborders, 7 Families, 22 Genera, 108 species and 12 varieties. The dominant species were 4 taxa, which were Achnanthes alteragracillima, A. convergens, A. minutissima and Fragilaria construens var. venter during the investigation periods at 8 sites. Correlation coefficients between epilithic diatom communities and physicochemical factors were from -0.94 to 0.97. Correlation coefficients (r) between turbidity, QHEI and density, species number and indices of diatom communities were from -0.18 to 0.42 which was showed lower values than the values of chemical factors. Correlation coefficients (r) between QHEI and Epilithic diatom communities were showed the low values. Correlation coefficients (r) between TP and diatom indices (DAIpo, TDI) were 0.79 and 0.78, respectively. Therefore, epilithic diatom communities were greatly influenced by TP.

• Journal of Korean Society on Water Environment
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• v.30 no.6
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• pp.596-604
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• 2014

This research has studied the physicochemical environmental factors and communities of epilithic diatom and phytoplanktons at Hongcheon river from December 2011 to September 2012. In case of TN, the result was hypertrophic, and for TP, it ranged from mesotrophic to eutrophic. As for BOD, Hongcheon river was rated level II or better, according to the water quality level; values were found to be below 3mg/L at most sites. Total of 83 and 114 taxa of epilithic diatom and phytoplanktons respectively, were found during the research. When assessed using the TSI, it ranged from oligomesotrophic to eutrophic. In case of DAIpo, it ranged from 64.1 to 99.5, and TDI ranged from 51.5 to74.0. These results signify good water quality, level B or better, for Hongcheon river. P-IBI was rated moderate to low, which showed higher pollution than other indices. Among the biological water quality measures analyzed in the Hongcheon river study, DAIpo best matches TDI and BOD, while TDI showed greater pollution. Therefore, P-IBI appears to be inappropriate when assessing the domestic small rivers and lakes.

• Journal of Ecology and Environment
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• v.36 no.1
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• pp.95-100
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• 2013

Many countries have adopted a single, well-described approach to the use of phototrophs for monitoring river water quality, which involves the use of indices related to diatom composition at a site. Increasingly these indices have focussed on assessing ambient phosphate concentration. However, there is a wide range of other methods which can provide additional information to make up for any weaknesses in the standard method. Some of these methods are reviewed briefly here. They can be useful, for instance, when considering temporal and spatial variability in phosphate concentration at a particular site and providing much more insight on heavy metal or pesticide pollution than revealed by routine water analysis.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2004.04a
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• pp.95-96
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• 2004

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.91-102
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• 2010

Water quality and epiphytic diatom on the submerged stems of reed (Phragmites communis), which occupy 90% of the Donghwa wetland macrophytes were monthly monitored at three points such as inflow stream, high- and low-level wetlands, and outflow stream between March and October, 2005. 1) A diverse and high density of diatom species observed in the cold-season, especially Nitzschia palea and Nitzschia amphibia dominated the diatom community without wetlands. 2) High DAIpo and TDI indices were measured over the sampling periods and stations, regardless of nitrogen increase and phosphorus increase through the wetlands. 3) Higher density of diatom species in high wetland than low wetlands was attributed in the enough nutrients and light penetration by low growth of reed. Therefore, epiphytic diatom of reed stem in Donghwa wetland, where high nutrients released from the sediment and reed debris after the death of macrophytes, flourished with low canopy of low reed vegetation.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.373-377
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• 2004

Since, in 1970, diatoms and diatom indices was first used in measuring quality of streams and rivers at the Seine Water Agency in France, five other water agencies began to show interests since 1990. In 1994, associated with CEMAGREF (Centre National du Machinisme Agricole du Genie Rural et des Eaux et des Forets : environmental science and expertise for the sustainable management of land and water), the six French Water Agencies (Seine, Rhone-Mediterranee-Corse, Artois- Picardie, Loire-Bretagne, Rhin-Meuse and Adour-Garonne) developed a practical diatom index, which is liable to be used routinely in the territorial streams and rivers of whole France, and which is liable to promote and facilitate its use in monitoring water networks. In 1995, the first version of a biological diatom index (IBD) was generated by them. Since then, the software update for IBD calculation and the user's network have led to numerous practical applications in France. Furthermore, the Water Agencies have run applicable programs on the National Basin Network from 1996, and the initial data set of IBD was completed. Re- examination of the complete data set was done at the end of 1998, and the tests on different calculation options of the IBD led to a third version of this index in June,2000 (AFNOR NF T 90-354).

• Geomechanics and Engineering
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• v.33 no.1
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• pp.113-120
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• 2023

Coastal and offshore structures such as ports and offshore wind farms will often need to be built on fine-grained sediments. Geotechnical properties associated with sediment compressibility are key parameters for marine construction designs especially on soft grounds, which involve clay-mineral dominated fines that can consolidate and settle significantly in response to engineered and environmental loads. We conduct liquid limit tests and 1D consolidation tests with fine-grained soils (silica silt, mica, kaolin and bentonite) and biogenic soils (diatom). The pore fluids for the liquid limit tests include deionized water and a series of brines with NaCl salt concentrations of 0.001 m, 0.01 m, 0.1 m, 0.6 m and 2.0 m, and the pore fluids for the consolidation tests deionized water, 0.01 m, 0.6 m, 2 m. The salt concentrations help the liquid limits of kaolin and bentonite decrease, but those of diatom slightly increase. The silica silt and mica show minimal changes in liquid limit due to salt concentrations. Accordingly, compression indices of soils follow the trend of the liquid limit as the liquid limit determined the initial void ratio of the consolidation test. Diatoms are more likely to be broken than clastic sediments during to loading, and diatom-rich sediment is therefore generally more compressible than clastic-rich sediment.