• ALGAE
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• v.20 no.3
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• pp.197-205
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• 2005

Temporal variability in lake phytoplankton is controlled by a complex between hydrological and chemical factors, and biological interactions. We explored annual change of phytoplankton in Lake Daecheong, using phytoplankton analysis data from 1997 to 2002 (except 2000). The standing crop of phytoplankton was ranged from 3.5 x 10 to 1.5 x 106 cells mL$^{-1}$ and the highest mean value was at site 1. The class composition ratios of phytoplankton standing crop were divided into three classes. From January to March, diatoms showed a dominance (68.1-77.7%). From April to June, diatoms were mixed with cryptomonad etc. or blue-green algae. From July to October, blue-green algae showed a dominance (54.7-84.0%). In the case of green algae, the class composition ratios were below 10%. But green algae appeared all the year round.

• Journal of the Korean Geotechnical Society
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• v.16 no.6
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• pp.51-58
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• 2000

울산지역에 널리 분포하고 있는 해성 퇴적토에 대하여 깊이별로 물리, 화학 그리고 광물학적 특성을 파악하였으며, 이 지역에서 채취된 시료에 대하여 깊이별로 퓨준압말시험을 실시하였다. 본 논문을 위하여 울산 해성 퇴적토의 생성과정을 추정하고, X-선 회절 분석, X-선 형광분석 및 에너지분산분광분석을 실시하여 깊이에 따른 변화를 비교하였다. 울산 해성 퇴적토의 점토광물에 대한 정량분석결과, 일라이트, 카올리나이트, 녹니석, 스멕타이트 순으로 많게 나타났음, 화학성분 분석결과, SiO$_2$, $Al_2$O$_3$그리고 Fe$_2$O$_3$가 대부분을 차지하는 것으로 나타났다. 주사전자현미경 관찰결과, 유공충과 규조류가 관찰되었다. 표준압밀시험 결과, 울산지역의 해성 퇴적 점토는 깊이에 따른 변형거동이 화학적, 광물학적 분석결과와 마찬가지로 깊이에 따른 변화를 보이지 않아 같은 시디에 퇴적인 것으로 판단된다.

• ALGAE
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• v.31 no.1
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• pp.1-16
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• 2016

Paralia species have been frequently reported as P. sulcata in Korea, despite the species diversity within the genus. To understand the species diversity of Paralia in Korea, we collected phytoplankton samples at 79 sites from April 2006 to April 2015. Five Paralia species, P. fenestrata, P. guyana, P. marina, P. cf. obscura, and P. sulcata, were observed during this study, and we described their fine structure in terms of quantitative and qualitative morphological characteristics. To provide additional criteria to identify Paralia species more clearly, we morphometrically analysed four quantitative characteristics on valve diameter: pervalvar axis / diameter, internal linking spines / diameter, marginal linking spines / diameter, and fenestrae/diameter using non-metric multidimensional scaling (MDS). MDS analysis distinguished four Paralia species: P. guyana, P. marina, P. cf. obscura, and P. sulcata, with the exception of P. fenestrata. This new approach in using morphometric analysis is useful for the accurate identification of Paralia species.

• 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.

• Journal of the korean society of oceanography
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• v.32 no.1
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• pp.46-55
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• 1997

The quantitative determination of carotenoids, chlorophylls and their degradation products from marine phytoplankton was performed by reverse-phase high performance liquid chromatography (HPLC). Separated and quantified chlorophylls and their degraded products are chlorophyll a, b, c, chlorophyllide a, phaeophytin a, b and phaeophorbide a. Concentrations of six carotenoids including fucoxanthin, 19'-butanoyloxyfucoxanthin, 19'-hexanoyloxyfucoxan-thin, prasinoxanthin, alloxanthin, zoaxanthin/lutein were also determined from natural field samples by absorbance. Results of pigment analysis of field samples collected from the southern waters of the East Sea on October 8th, 1996 were reported. Concentration of chi a ranged from 7.2 to 180.4 ng/1. Concentration of chi b and chi c ranged from 22.7 to 53.7 ng/1 and from 3.3 to 58.5 ng/1, respectively. Significant concentrations of phaeophytin a, and chlorophyllide a were also detected at different depths. Fucoxanthin, 19'-hexanoyloxyfucoxanthin and zoaxanthin/lutein were the most abundant carotenoids and 19'-butanoyloxyfucoxanthin, prasinoxanthin and alloxanthin were also detected relatively at low concentrations. These results of pigment analyses suggest predominance of diatom, prymnesiophytes and cyanobacteria and presence of crysophyte, green algae (prasinophyte and prochlorophyte), and cryptophyte in the study area on October 8th, 1996, We report prymnesiophyte for the first time as an important biomass component of marine phytoplankton in the study area. Vertical profiles for the concentration changes of the major pigments were also given.

• Ocean and Polar Research
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• v.44 no.2
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• pp.161-177
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• 2022

Microalgae can attach to the surface of ships and then spread to various areas by means of ship transport. The introduction of invasive species through ships is recognized as a marine problem worldwide. Identification of attached microalgae is necessary to investigate such movement between countries through ships. In the present study, through analytical methods we reviewed research data to identify the taxa of domestic attached microalgae and assess the ecological impacts of such microalgae. A total of 87 genera and 153 species (143 species of diatoms, 10 species of cyanobacteria, and 4 genera of dinoflagellates) were identified as native attached microalgae in Korea, and diatoms accounted for 93% of the total. Most of these attached microalgae were identified through research on natural substrates such as seaweeds and bedrock, and some were also identified through experiments using artificial adherent plates. To date, there is no information on microalgae attached to international ships and introduced into Korea. Molecular genetic analysis and systematic management through on-site sampling of international ships, microscopic analysis, and meta-barcoding are necessary to assess the inflow and spread path of hull-attached marine alien species and evaluate the risk they pose to the domestic ecosystem.

• Journal of the Mineralogical Society of Korea
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• v.19 no.3 s.49
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• pp.129-138
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• 2006

In this study, we identified the secondary precipitates from Samsan-jeil and Sambong mine, Goseong, Gyeongnam by means of scanning electron microscopy, electron probe microanalysis and X-ray powder diffraction analysis. Copper sulfide minerals had been produced from the mines during last few decades, however they are not worked. White and blue precipitates were found at the downstream of mine rock dump at Sambong mine and green one was at Samsan-jeil mine. The white precipitate covered the host rock surface with thickness of $30{\mu}m$, and is a kind of diatom with $10{\mu}m$ in length and $3{\mu}m$ in width. It is a species Fragilaria constuens, which is contained a order Pennales(pennate diatom) and lives in fresh water. The blue precipitate is the alteration product of chalcopyrite. It resultes in the increase in the ratio Cu:Fe from 5 to 13. The green precipitate has worm-like morphology with $10{\sim}20nm$ in diameter and $200{\sim}300nm$ in length. It is mainly composed of secondary copper sulfate such as woodwardite. However, it could be formed by the activity of microorganism, because the copper content is more than any secondary copper sulfate reported in copper sulfide mine. In order to identity the green precipitate exactly, the further research is needed.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.139-149
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• 2012

Four in situ incubation experiments were conducted in May, August and November 2009, as well as February 2010 to determine the seasonal primary productivity and the community structure of phytoplankton at the Seomjin estuary. The primary production of phytoplankton ranged from 9 to 3560 mgC $m^{-2}\;d^{-1}$. Primary productivity was the highest in the summer season (August), which was influenced by improved optical and temperature conditions of the water, as well as the supply of nutrients derived from its surrounding watershed. Particularly, the upper station (SJ-1, SJ-2) of Seom-jin estuary showed a higher productivity, as a result of inflow of input nutrients originated from the terrestrial source. The fucoxanthin, as an index pigment of diatoms showed the highest concentration (0.74~9.51 ${\mu}g\;L^{-1}$) at all stations, occupying 30~80% to total Chl a concentrations. The phytoplankton species composition determination, using a microscope showed similar results to the pigment analysis, which indicated diatom Skeletonema costatum, as the dominant species. The primary productivity in Seom-jin estuary indicates temporally and spatially large variation, according to different environmental conditions. Also, Skeletonema costatum has euryhaline features with relatively higher contribution.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.117-128
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• 2010

The water qualities of Namdae-stream, Yeongok-stream and Sacheon-stream were examined, by using physicochemical factors, trophic status and epilithic diatoms from May 2008 to February 2009. The physicochemical water qualities of three streams were, except for some construction areas and sites of downstream, generally good, having less concentration than BOD of $2\;mg\;L^{-1}$. As for the sites of downstream, there were ongoing pollution such as graduation of nutrients in Namdae-stream and Sacheon-stream, due to salinity of seawater and topographical feature of the closed estuary. The examination of trophic status of Namdae-stream showed mesotrophic status in all the sites. Also, eutrophication was in progress as from the upstream to the downstream of Yeongok-stream, and Sacheon-stream showed eutrophic status in all its sites. As a result of the biological water quality assessment, Namdae-stream, excluding the downstream site, came out to be $\beta\sim\alpha$-oligosaprobic, and biological water quality was good, having TDI less than 50. Some construction sites and downstream site of Namdae-stream are $\beta$-mesosaprobic, and with the TDI over 70, the biological water quality assessment came out to be polluted. Yeongok-stream is $\beta\sim\alpha$-oligosaprobic, and its biological water quality is good, having TDI less than 40. Sacheon-stream, excluding the upstream site on May 2008 and February 2009, is $\beta\sim\alpha$-mesosaprobic, and its TDI over 70 shows that it has been polluted. The correlation analysis showed a high correlation in both DAlpo and TDI. Also, biological assessment of water quality (DAIpo, TDI) showed higher correlation with TSI rather than BOD.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.610-619
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• 2018

This study was carried out in August and September 2016 to investigate the species composition and biomass of benthic diatoms in Yubu Island, Gomso Bay, Imja Island, and Yeoja Bay tidal flat of Southwestern coast. There were 181 species of 48 genera in Yubu Island tidal flats, 194 species of 51 genera in Gomso Bay tidal flats, 224 species of 64 genera in Imja Island tidal flats and 188 species of 56 genera in Yeoja Bay tidal flats. A total of 274 species of 70 genera appeared. Pennales appeared more widely than Centrales and were dominated by Paralia sulcata and Navicula spp. Biomass of Yubu Island tidal flat ranged from $18.8-136.1mg\;m^{-2}$, $31.9-215.7mg\;m^{-2}$ in Gomso Bay, $2.9-120.2mg\;m^{-2}$ in Imja Island and $10.1-147.7mg\;m^{-2}$ in Yeoja Bay. The range of total biomass from 4 areas was $2.9-215.7mg\;m^{-2}$. The concentration of phaeopigment and degradation product of chlorophyll-a was $1.7-470.8mg\;m^{-2}$ in Yubu Island tidal flat, $52.3-277.2mg\;m^{-2}$ in Gomso Bay, $0.6-78.9mg\;m^{-2}$ in Imja Island and $39.1-346.3mg\;m^{-2}$ in Yeoja Bay. Compared with the results reported in this study area and the domestic tidal flats, it cannot be directly compared and evaluated due to various factors such as the timing of the survey, the frequency of the survey, the analysis method and geography. The southwestern coast of Korea has a variety of benthic diatoms and the high concentration of chlorophyll-a is the main determinant of primary productivity.