• Korean Journal of Environmental Biology
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• v.34 no.1
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• pp.18-29
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• 2016

The effects of water temperature, salinity, water column nutrient contents, and phytoplankton primary productivity on pigment composition and concentration, as well as primary productivity of Pyropia yezoensis Ueda purple lavers were studied at the primary cultivation areas in the Manho (Jindo-Haenam) region on the southwestern coast of Korea in March 2014. The water temperature was $9.1{\sim}9.6^{\circ}C$, salinity was 32.5~33.1, and transparency was 0.7~1.5 m. The shallow euphotic depth resulted from the high turbidity. Water column dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and silicate concentrations were $3.59{\sim}5.73{\mu}M$, $0.16{\sim}0.41{\mu}M$, and $12.41{\sim}13.94{\mu}M$, respectively. Chlorophyll a (Chl a) concentration was $0.51{\sim}1.25{\mu}g\;L^{-1}$. Nanoplankton ($0.7{\sim}20{\mu}m$ size class) accounted for 58% of the total Chl a concentration. Fucoxanthin was the dominant photosynthetic pigment at all sites. Microplankton ($20{\sim}200{\mu}m$ size class) accounted for 64% of the total fucoxanthin concentration. The primary productivity of phytoplankton was $57.72{\pm}4.67(51.05{\sim}66.71)mg\;C\;m^{-2}d^{-1}$. The nanoplankton ($0.7{\sim}20{\mu}m$ size class) accounted for 77% of the total phytoplankton primary productivity. The calculated phytoplankton primary productivity was $11,337kg\;C\;d^{-1}$. The primary productivity of Pyropia blades was $1,926{\pm}192(1,102{\sim}2,597)mg\;C\:m^{-2}d^{-1}$, i.e., calculated as $39,295kg\;C\;d^{-1}$. The total primary productivity of phytoplankton and Pyropia blades was $50,632kg\;C\;d^{-1}$. The primary productivity of Pyropia blades was 3.5 times greater than that of phytoplankton in the Manho region on the southwestern coast of Korea.

• 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.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.1
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• pp.27-41
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• 2008

Distribution characteristics of phytoplankton community were investigated by HPLC and flow cytometry in Jeju Strait and the Northern East China Sea (NECS) in May 2004, in order to understand the relationship between physical environmental factors and distribution pattern of phytoplankton communities. Based on temperature and salinity data, three distinct water masses were identified; warm and saline Tsushima Warm Current (TWC), which is flowing from northwest of Jeju Island, warm and low saline water at the center of Jeju Strait, which is originated from China Coastal Water (CCW) and relatively cold and high saline water originated from Yellow Sea at the bottom of the Jeju Strait. At Jeju Strait, less saline water (<33 psu) of 15 km width occupied surface layer up to 20 m which located at 20 km offshore and strong thermal front between warm and saline water and cold and less saline water was found in the middle of the Jeju Strait. Vertical transect of temperature and salinity at the NECS also showed that low saline (<33 psu) water occupied the upper 20 m layer and cold and saline water was present at the eastern part. Chl a was measured as $0.06{\sim}3.07\;{\mu}g/L$. Spring bloom of phytoplankton was recognized by the high concentrations of Chl a at the low saline water masses influenced by the CCW and subsurface chlorophyll maximum layer appeared between $20{\sim}30\;m$ depth, which was at thermocline depth or below. Abundances of Synechococcus and picoeukaryote were $0.2{\sim}9.5{\times}10^4\;cells/mL$ and $0.43{\sim}4.3{\times}10^4\;cells/mL$, respectively. Dinoflagellate, diatom and prymnesiophyte were major groups and minor groups were chlorophyte+prasinophyte, chrysophyte, cryptophyte and cyanophyte. Especially high abundance of dinoflagellate was identified by high concentration (>1\;{\mu}g/L$) of peridinin at the bottom of the thermocline, which showed an outbreak of red tide by high density of dinoflagellates. Abundances of picoeukaryote in Jeju Strait were about $5{\sim}10$ times higher than abundance measured in Kuroshio water and showed a good correlation with Chl b (Pras+Viola), which implies the most of population of picoeukaryote was composed of prasinophytes. Prochlorococcus was not detected at all, which suggests that Kuroshio Current did not directly influenced on the study area. Based on the strong negative correlations between biomass of phytoplankton (Chl a) and temperature+salinity, the primary production and biomass of phytoplankton in the study area were controlled by the nutrients supply from CCW.

• Korean Journal of Environmental Biology
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• v.24 no.1 s.61
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• pp.81-88
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• 2006

The cell abundance and marker pigment distribution patterns of picophytoplankton in the Chuuk Lagoon, tropical South Pacific, were analyzed flow cytometry and HPLC. Also, respective contribution of Synechococcus, Prochlorococcus and picoeukaryotes on estimated carbon biomass was evaluated. Synechococcus and Prochlorococcus showed contrasting distributional patterns in the waters of Chuuk Lagoon. Relatively high concentration of Synechococcus was observed near Weno Island but the concentration decreased toward the Northeast Passage. However, Prochlorococcus showed an opposite distributional pattern. Picoeukaryotes did not show any significant variable difference. The range of divinyl chlorophyll a (Chl. $\alpha$) concentration, marker pigment of Prochlorococcus, was $1.2\sim180.3\;ng\;L^{-1}$ and higher concentrations were observed at the stations near the Northeast Passage than stations near Weno Island. This pigment pattern was similar to cell abundance pattern indicating that chi. a2 may be a useful biomass indicator. On the other hand, the range of zeaxanthin concentrations was $61.4\sim135.8\;ng\;L^{-1}$ showing comparatively less significant variation indicating zeaxanthin influence derived from Prochlorococcus. Estimated carbon biomass of Synechococcus contributed 68% of total picophytoplankton biomass. Prochlorococcus and picoeukaryotes respectively contributed 17.1% and 14.9% of total picophytoplankton biomass.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.2
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• pp.80-89
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• 1998

To understand the temporal variation of phytoplankton community in the Antarctic coastal ecosystem, physicochemical parameters, chlorophyll a, and primary productivity were measured as a component of the 7th KARP (Korea Antarctic Research Program) in 1994. Data were collected every month between February and December except four months (June-September) when the study area was frozen. Chlorophyll a concentrations ranged from negligible to 3.03 ${\mu}g/l$, averaging 0.63 ${\mu}g/l$. The primary productivity ranged 0.53-18.95 mg C/$m^3{\cdot}day$, and the depth-integrated primary productivity ranged 41.28-560.20 mg C/$m^3{\cdot}day$. A positive relationship was observed between the phytoplankton biomass and irradiance ($r^2$=0.29, p < 0.01). The degree of correlation between the primary productivity and irradiance ($r^2$=0.85, p < 0.001) was significantly higher than that between the phytoplankton biomass and irradiance. However, neither temperature nor inorganic nutrients seem to affect the temporal variation of primary productivity.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.304-312
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• 2005

Effects of two endocrine disrupters (EDs) , nonylphenol (NP) and diethylhexyl phthalate (DEHP), on the population growth and morphology of two freshwater HABs (harmful algal blooms) , Microcystis aeruginosa and Stephanodiscus hantzschii, which frequently evoked the hazard bloom in an eutrophic lakes and reservoirs worldwide, were examined with seven different concentrations of EDs (0.01, 0.05, 0.1, 1,2, 2.5 and 3 ppm). Even at concentration below 0.01 ppm, NP strongly inhibited the algal growth of both M. aeruginosa and S. hantzschii, regardless of the algal growth phase. Morphologically, the algal cell treated with NP gradually lost green color in cytoplasm, became smaller in cell size, and then, was hardly seen in microscopic field. On the other hand, DEHP employed did not affect two algae at all concentrations, and rather stimulated the growth by about 10% with a treatment at 3.00 ppm compared to control. These results indicate that the continuous input of EDs, DEHP into the natural water system plays a crucial role to enhance or help an outbreak of algal bloom in eutrophic waters.

• Korean Journal of Environmental Biology
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• v.18 no.4
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• pp.425-440
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• 2000

The physico-chemical characteristics and the concentrations of chlorophylls of coastal seawater were investigated to know the seasonal variations of biological oceanographic environments in the Islands of Ullungdo(U) and Dokdo(D). The samplings of sea water according to different depths were performed four seasons (May, June, August and November) in five stations along the coast of Ullungdo Island and 3 times (June, August and November) in three stations around the coast of Dokdo Island. The seasonal variations of sea water temperature showed that the formation of thermocline in August was distinct in comparison to the other seasons. The sea water in the surface was influenced by low temperature-high salinity in May and with high temperature-low salinity in the investigated area. The amount of seston was high in May (5.3-15.0mg/l) and was low in August (1.4-4.9mg/l) in ullungdo island. for the nutrients or sea water in Ullungdo Island, the concentrations of nitrate and ammonium were higher than Dokdo Island (nitrate-max. of U in August : 0.10-11.50$\mu\textrm{g}$/1, max. of D in August : 2.92-8.10$\mu\textrm{g}$/l : ammonium-max. of U in November : 14.18-20.69$\mu\textrm{g}$/l, max. of D in June : 0-1.78 $\mu\textrm{g}$/l). The high concen-tration of chlorophylls showed on the deeper layer from 30 m to 50 m in August (U 30 m : 0.85$\mu\textrm{g}$/l ; D 50m : 1.02 $\mu\textrm{g}$/l), while the concentrations of chlorophylls were even in May, June and November in the deeper layer of surface layer. In conclusion, the establishment of thermocline in deeper area of the euphotic layer in August was a trigger far the development of phytoplankton, while the complex physico-chemical system by diverse currents and vertical mixing of sea water in the area induced the even distribution of phytoplankton in both epilimnion and hypolimnion in May, June and November.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.2
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• pp.282-297
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• 2019

Detection of mesoscale oceanic eddies using satellite data can utilize various ocean parameters such as sea surface temperature (SST), chlorophyll-a pigment concentration in phytoplankton, and sea level altimetry measurements. Observation methods vary for each satellite dataset, as it is obtained using different temporal and spatial resolution, and optimized data processing. Different detection results can be derived for the same oceanic eddies; therefore, fundamental research on eddy detection using satellite data is required. In this study, we used ocean color satellite data, sea level altimetry data, and infrared SST data to detect mesoscale eddies in the East Sea and compared results from different detection methods. The sea surface current field derived from the consecutive ocean color chlorophyll-a concentration images using the maximum cross correlation coefficient and the geostrophic current field obtained from the sea level altimetry data were used to detect the mesoscale eddies in the East Sea. In order to compare the eddy detection from satellite data, the results were divided into three cases as follows: 1) the eddy was detected in both the ocean color and altimeter images simultaneously; 2) the eddy was detected from ocean color and SST images, but no eddy was detected in the altimeter data; 3) the eddy was not detected in ocean color image, while the altimeter data detected the eddy. Through these three cases, we described the difficulties with satellite altimetry data and the limitations of ocean color and infrared SST data for eddy detection. It was also emphasized that study on eddy detection and related research required an in-depth understanding of the mesoscale oceanic phenomenon and the principles of satellite observation.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.1
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• pp.76-87
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• 2014

Chlorophyll a in seawater which is an indicator of phytoplankton biomass and primary production is determined by High Performance Liquid Chromatography (HPLC), Fluorometry and Spectrophotometry. In this study, various methods for chlorophyll a determination in seawater are compared using in situ seawater samples from Korean seas. Three inter-laboratory comparison campaigns were carried out using chlorophyll a standard samples (R0) and in situ seawater samples, collected from the East China Sea (R1) and the East Sea (R2). 6 laboratories by HPLC methods, 4 laboratories by fluorometry, and 3 laboratories by spectrophotometry participated. Precisions, defined as the coefficient of variation (CV) were within 9% in standard samples, 0.8~20% (average: 6.1%) in R1, 4~21% (average: 13.2%) in R2. Discrepancy in three methods was approximately 20% within the range of the sample homogeneity intended the laboratory precision (R1: 8%, R2: 15%). The discrepancy in laboratories was greater than the discrepancy in methods. The chlorophyll a concentrations can be produced within 20% discrepancy in spite of using different methods. It is recommended to consider this 20% discrepancy when using the chlorophyll a data produced by different laboratories and different methods.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.603-613
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• 1996

Hydrographic conditions (temperature, salinity, dissolved oxygen), nutrients, chlorophyll-a and suspended solid have been studied in the southwestern coastal area of Cheju Island from April 1993 to March 1994. Vertical profile of temperature, salinity and chemical properties (nutrients, chlorophyll-a) distribution in th southwestern sea of Cheju Island showed a upwelling feature. Although it was not clear in winter season, it seems to continued through out the year. In the surface water at the upwelling areas, the ranges of dissolved oxygen, nitrate, phosphate and silicate was $3.30\~8.43\;ml/l,\;0\~7.12{\mu}g/l,\;0.03\~1.75{\mu}g-at/l\;and\;2.75\~22.32\;{\mu}g-at/l$l, respectively. Nutrients was higher in the shore water than in the offshore water, because sufficient supply of nutrients from the bottom water by coastal upwelling. In November, especially high concentration silicate was observed at all the stations and depth in the study area. At all station of bottom water (down to the depth of 60 meter), concentration value of dissolved of gen was as high as 8 ml/l. Mean values of N/P was 8.0, lower than Redifield ratio of 16. The mean values of Si/P was observed to 46.3 in southwest of Cheju Island. Concentration of chlorophyll-a was in the range of $0.04\~2.36\;{\mu}g/l$. Concentration of chlorophyll-a in surface orator at all station was especially higher in spring than in other seasons. Mean concentration value of suspended solids was 3.14 mg/l $(0.75\~8.47\;mg/l)$. Ratio of the volatile suspended solids to the suspended solids was higher in the inshore water $(53\%)$ than in the offshore water $(46\%)$, and higher in the surface water than in the bottom water.