• Korean Journal of Ecology and Environment
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• v.34 no.2 s.94
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• pp.90-97
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• 2001

The seasonal changes in phytoplankton standing crops, species composition, dominant species, species diversity and physico-chemical characteristics in Woopo and Mokpo swamps were studied from January to December, 1998. Phytoplankton of a total 353 taxa were identified, the composition of phytoplankton community was characetrized by green algae and diatoms and quantity composition of standing crops was dominated by green alga Oscillatoria sp. was especially prominent. The standing crops varied from 108 cells/ml and 118 cells/ml to 19,178 cells and 38,393 cells/ml in Woopo and Mokpo swamps, respectively. The maximum algal density was observed in November, Micractinium pusillum and Oscillatoria sp. usually contributed 83.2% to total cell numbers in Woopo swamp. However, the maximum density occurred in May when Oscillatoria sp. formed bloom in Mokpo swamp. The low species diversity of the phytoplankton coincided with maximum standing crops of the filamentous blue-green alga Oscillatoria sp. and green alga Micractinium pusillum in May and November.

• Journal of Aquaculture
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• v.8 no.4
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• pp.355-366
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• 1995

In order to identify some suitable diatoms as a live food source, effects of seven diatom species (Chaetoceros simplex, Navicula incerta, Phaeodactylum tricornutum, Nitzschia closterium, Skeletonema costatum, Thalassiosira pseudonana, Thalassiosira weissflogii) were examined on specific growth rate, mean celt volume, chemical composition and general fatty acid composition. In cell volume. T. pseudonana was the smallest $(125{\mu}m^3)$ and T. weissflogii the largest $(824{\mu}m^3)$. However the specific growth rate of the largest diatom was the lowest (0.5016/day), and that of S. costatum was the highest (0.9928/day). The crude protein content of seven diatom species varied from $18.96\%$ (T. pseudonana) to $24,4\%$ (T, weissflogii). The crude lipid content of C. simplex was the highest $(8.43\%)$, and that of T. pseudonana was the lowest $(3.13\%)$. The total content of polyunsaturate fatty acids which are important for bivalve larvae was higher in C. simplex than those in other species. The total percent of polyunsaturate fatty acids from N. incerta and T. weissflogii was relatively lower than that from other species. Dietary value of seven diatom species were finally examined with Pacific oyster larvae Crassostrea gigas. In this experiment, C. simplex showed the highest survival rate and growth, and the larvae feed on S. costatum and T. weissflogii showed the poorest results. This results C. simplex could be more useful live food for bivalve larvae than other diatom species tested.

• Journal of Environmental Impact Assessment
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• v.28 no.6
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• pp.507-524
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• 2019

The purpose of this study was to validate the EFDC model for the weir pool of Gangjeong-Goryong Weir located in Nakdong River, and evaluate the effect of flow control and phosphate loading reduction on the water quality and algae biomass by group (Diatom, Green, Cyanobacteria). As a result of model validation using 2018 experimental data,the time series of water level and vertical distribution of water temperature, DO, organic matter, nitrogen, and phosphorus time series were properly simulated. Seasonal fluctuations of algae biomass by group were adequately reproduced, but the deviations between measured and simulated values were significant in some periods. As a result of scenario simulations to control the water level and flow rate, the thermal stratification was resolved as the water level was lowered and the flow rate increased. The flow velocity at which the water temperature stratification was resolved was about 0.1 m/s, which is consistent with the previous study results of Baekje Weir in Geum River. Simulations of the 2Q flow scenario showed that Chl-a decreased by 8.7% and the cell density of diatom and green algae declined. The cell density of cyanobacteria increased, however, because the high concentrations of cyanobacteria in the upstream boundary conditions directly affected downstream due to increased flow velocity. In the scenario simulation of reducing the influent phosphate load concentration (average 0.056 mg/L) to 50%, Chl-a decreased by 13.6%.The results suggest that the upstream algae concentration and phosphorus load reduction should be considered simultaneously with hydraulic control to prevent algal overgrowth of Gangjeong-Goryong Weir.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.267-273
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• 2023

Algae are an important component of the ecosystem. However, the excessive growth of cyanobacteria has various harmful effects on river environments, and diatoms affect the management of water supply processes. Algal monitoring is essential for sustainable and efficient algae management. In this study, an object detection model was developed that detects and classifies images of four types of harmful cyanobacteria used for the criteria of the algae alert system, and one diatom, Synedra sp.. You Only Look Once(YOLO) v8, the latest version of the YOLO model, was used for the development of the model. The mean average precision (mAP) of the base model was analyzed as 64.4. Five models were created to increase the diversity of the input images used for model training by performing rotation, magnification, and reduction of original images. Changes in model performance were compared according to the composition of the input images. As a result of the analysis, the model that applied rotation, magnification, and reduction showed the best performance with mAP 86.5. The mAP of the model that only used image rotation, combined rotation and magnification, and combined image rotation and reduction were analyzed as 85.3, 82.3, and 83.8, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.1
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• pp.24-29
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• 2003

In the previous reports, the authors isolated two strains of marine bacteria, Shewanella sp. SR-14, which has Chaetonros sp. growth inhibition activity, and Vibrio alginolyticus, that did not affect growth of the alga. In the present study, fatty acid compositions of diatoms, Chaetoceros calcitrans and Skeletonema costatum, and marine bacteria, Shewanella sp. SR-14 and V. alginolyticus, were analyzed. Changes of fatty acid composition in the diatoms grown with the marine bacteria were also determined. Major fatty acids of Sbewanella sp. SR-14 were 16:1n-7 $(29.4\%)$ and 16:0 $(19.2\%)$ during incubation in peptone broth at $20^{\circ}C$ for 3 days. The compositions of V. alginolyticus detected were 16:0 $(23.7\%),$ 16:1n-7 $(27.7\%)$ and 18:1n-7 $(21.0\%).$ C. calcitrans consisted of 16:1n-7 $(33.3\%),$ 16:0 $(27.1\%)$ and 14:0 $(12.1\%).$ S. costatum mainly contained 16:1n-7 $(28.9\%),$ 16:0 $(21.6\%)$ and 20:5 $(19.8\%).$ When halves of cell numbers of C. calcitrans were moribund cells by Shewanella sp. SR-14, the C. calcitrans and S. costatum simultaneously cultured with the bacteria were harvested by filtration with GE/D glass microfibre filter. In the fatty acid composition of both diatoms, saturated fatty acid contents in both diatoms grown with Shewanella sp. SR-14 were decreased, but unsaturated fatty acid contents were increased. The differences were greater in C. calcitrans than those in S. costatum. During the growth of diatoms with V. alginolyticus, C. calcitrans showed increase of saturated fatty acid contents and decrease of unsaturated fatty acid contents; however, S. costatum did not show sharp difference in fatty acid content. In this study, Shewanella sp. SR-14, which showed growth inhibition activity against C. calcitrans, influenced on the changes of fatty acid contents in the diatom. It was suggested that increased unsaturated fatty acid was synergistically activated algal growth inhibition activity of Shewanella sp. SR-14.

• 한국해양학회지
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• v.16 no.2
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• pp.57-98
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• 1981

This study deals with the marine dinoflagellates observed in 50 samples collected in the vincinity of Yeosu from August 1979 to May 1980. Forty-nine species were identified and these taxa are attributed to 10 genera, of which 2 are infraspecific taxa. Two families, 3 genera, and 32 species are new records for the Korean coastal waters. Small dinoflagellates recorded in this study are ascribed to the use of volumetric samplers instead of nets. In this area, the armored forms are the most important components of the dinoflagellates (39 taxa). All species are illustrated by photomicroscopy. There are 49 pictures of taxa. An attempt has been made to provide more correct references to each species. There are comparative descriptive information, taxonomic comments, and distributional data for each species.

• Journal of Environmental Impact Assessment
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• v.10 no.2
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• pp.109-121
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• 2001

Water environment and freshwater algae were studied in the upstream of the Tamjin River Dam. Among the environmental factors, DO concentration in the Tamjin River ranged from 9.0 mg $O_2/l$ to 9.2 mg $O_2/l$, pH from 7.0 to 7.1 and conductivity from $98{\mu}S/cm$ to $100{\mu}S/cm$. Average concentration of $NH_4$ and $NO_3$ ranged from $40{\mu}g\;N/l$ to $56{\mu}g\;N/l$ and from $489{\mu}g\;N/l$ to $611{\mu}g\;N/l$, respectively. $NO_3$ was more plentiful above 9~15 fold than that of $NH_4$. Average concentrations of soluble reactive phosphorus and soluble reactive silicon were $2{\mu}g\;P/l$ and 1.6 mg Si/l, respectively. Particulaly, Si nutrient increased by heavy rain events during summer season. The ratios of N/P and Si/P ranged from 248 to 261 and from 640 to 740, respectively. It is assumed that P would be limiting nutrient on the freshwater algal growth. Average content of planktonic chlorophyll-a ranged from $5{\mu}g/l$ to $13{\mu}g/l$. Mean contents of chlorophyll-a, phaeo-pigment and ash-free dry matter of periphyton were $50.3mg/m^2$, $11.9mg/m^2$, $11.5g/m^2$ in the main stream and $30.1mg/m^2$, $5.6mg/m^2$, $7.8g/m^2$ in the tributary. By comparison of the epilithon biomass, the main stream was higher with 1.5~2.1 fold than the tributary. The impotant algae were composed of diatom Achnanthes linearis, A. minutissima, Fragilaria crotonensis, Gomphonema gracile, Tabellaria flocculosa and blue-green algae Microcystis aeruginosa. In the relative abundance of the phytoplankton and epilithon, the serial dominance were diatom > green algae > blue-green algae, and diatoms were very abundant in comparison with other algal phylum.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.4
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• pp.373-379
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• 1994

Final biomass yields(cells/ml) and growth rates(divisions/day) of 4 clones of marine diatoms isolated from the Korean coastal waters were measured in media with 6 different levels of added cadmium concentrations. A neritic diatom, GS-12(Chaetoceros sp.), showed no growth at 0.1ppm cadmium, and its $IC_{50}$ for final biomass yield and growth rate was 0.03 and 0.02ppm, respectively. Two clones isolated from tidal pool, NC-37 and NC-29, showed enhanced tolerance to cadmium toxicity. Extremely high tolerance to cadmium addition was found in J-21 from a eutrophicated bay, with its high $IC_{50}$ for biomass yield(1.07ppm) and growth rate(1.92ppm). Present results implied a habitat related pattern of coastal diatom clones in the cadmium tolerances. Except GS-12, the other three diatom clones are considered to be highly tolerant to cadmium stresses.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.79-88
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• 1991

To study the distribution patterns of epiphytic diatom on Porphyra species and ambient water phytoplankton, samples were collected in the Gaeya Island, Kyukpo, and Mokpo of the Yellow Sea from February 1989 to March 1990. Foully species of epiphytic diatoms were observed. Of these, the dominant species of epiphytic diatoms are Limophora dalmatica, L. abbreviata, Melosira nummuloides, Paralia sulcata, Achnanthes javanica var, subconstricta, Grammatophora oceanica, Navicula sp., Synedra sp., Pinnularia sp., Fragilaria striatula, Cocconeis scutellum var. parva. Licmophora dalmatica predominated troughout the study period. Phytoplankton standing stocks were relatively larger than those of other coastal areas in the Yellow Sea, Korea. Distribution patterns of epiphytic diatoms and the ambient water phytoplankton in Gaeya Island were similar to those of Kyukpo, but different from Mokpo.

• Korean Journal of Environmental Biology
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• v.28 no.3
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• pp.115-124
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• 2010

In order to find out the short-term phytoplankton dynamics during summer season in Jinhae Bay, we investigated the environmental factors and phytoplankton population densities at 16 stations. A total of 66 phytoplankton species were appeared, diatoms occupied more than 80% of total species, and the others were dinoflagellates and raphidophyceaes. The dominant species were diatoms Chaetoceros affinis, C. didymus, C. pseudocurvisetus, Leptocylindrus danicus, Pseudonitzchia pungens, Skeletonema costatum and dinoflagellates Cochlodinium polykrikoides, Gymnodinium impudicum, Karenia mikimotoi, Prorocentrium minimum, Protoperidinium bipes and Scrippsiella trochoidea. According to multidimensional scaling (MSD) and cluster analysis based on phytoplankton community data from each station, the Jinhae bay was divided into two groups. The first group included stations in the inner part of Masan Bay, which is strongly influenced by high nitrogen loading and low salinity by river discharge. The second group included the other remained stations. Based on canonical correspondence analysis (CCA), small-size dinoflagellates K. mikimotoi, P. minimum, P. bipes and S. trochoidea and centric diatom C. pseudocurvisetus and S. costatum, which is dominanted in the inner area of bay, were related with DIN (ammonium, nitrate, nitrite). These results imply that the study area was grouped into the two water masses (inner and outer water of Masan Bay) and inner waters had higher phytoplankton abundances and Chl.a concentration than outer waters. As a result, summer phytoplankton peaks in the inner shallow bay were stimulated by increases in nitrogen and temperature.