• Korean Journal of Environmental Biology
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• v.32 no.1
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• pp.75-87
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• 2014

This study describes about the spatio-temporal distributions in phytoplankton community such as species composition, standing crop and dominant species from May 2006 to February 2007 in the Jangsu bay and the northwestern parts of Gamak bay. Based on the principal component analysis (PCA) of the environmental factors as well as biological parameters, the bio-oceanographical characteristics were analysed. A total of 83 species of phytoplankton belonging to 47 genera were identified. Whereas diatoms and dinoflagellates occupied more than 65% and 30% of total species, respectively. The annual dominant species were Chaetoceros affinis, Paralia sulcata and Bacillaria paxillifera in spring, Chaetoceros didymus, Ch. affinis and Octactis octonaria in summer, Skeletonema costatum-like species and B. paxillifera in autumn. Moreover phytoplankton cell density was ranged between 3.1 $cells{\cdot}mL^{-1}$ in spring and 521.0 $cells{\cdot}mL^{-1}$ in winter. It fluctuated with an annual mean of 76.0 $cells{\cdot}mL^{-1}$ between the lowest value of 7.6 $cells{\cdot}mL^{-1}$ in spring and the highest value of 220.2 $cells{\cdot}mL^{-1}$ by Skeletonema costatum-like species in winter. Briefly, the phytoplankton cell density in the mixing seasons was higher in comparison with the other seasons. According to the PCA, the biological oceanographic characteristics of the Jangsu bay was affected by the introduction of outside seawater particularly in temperature increasing seasons, and the other seasons, it may be described the light intensity, and mix between inner and outer bay sea waters.

• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.292-303
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• 2016

This study described the spatial distributions of marine environmental factors such as water temperature, salinity, chlorophyll a concentration and turbidity, and characteristics of phytoplankton community such as species composition, standing crops and dominant species at 19 fishing ports around Jeju Island during the early summer of 2016. I analyzed bio-oceanographical characteristics using principal component analysis (PCA) of the environmental factors and biological parameters. Water temperature, salinity, chlorophyll a and turbidity ranged from 17.6 to $20.7^{\circ}C$, from 26.19 to 32.33 psu, from 0.76 to $7.13{\mu}g\;L^{-1}$, and from 0.51 to 14.49 FTU, respectively. A total of 51 species of phytoplankton belonging to 35 genera were identified. In particular, diatoms and dinoflagellates accounted for more than 56.8% and 27.4% of all the species, respectively. Moreover, the number of phytoplankton species was controlled by salinity. Phytoplankton cell density ranged from $2.9cells\;mL^{-1}$ to $185.9cells\;mL^{-1}$. The dominant species were Navicula spp. Stephanopyxis turris, Eutreptiella gymnastica and Mesodinium rubrum. Environmental factors and the phytoplankton community varied greatly between sampling sites. According to PCA, the biological oceanographic characteristics of the around Jeju Island were characterized by meteorological factors such as air temperature, precipitation and discharge of ground water during early summer.

• Journal of the korean society of oceanography
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• v.34 no.2
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• pp.95-112
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• 1999

To investigate a phytoplankton community structure and its biomass distribution in the Korea Strait, phytoplankton pigments were quantitatively measured by HPLC method, with hydro-graphic conditions in August and October, 1996. The measured chi. a concentrations were in the range of 7.1-1,280.7 ng/1. Horizontal distribution pattern of chi. a in summer (August) was very different from that of autumn (October). High concentration of chi. a occurred near the coast with relatively low salinity (< 33%). Vertically, the highest concentrations of pigments at most of the stations were found near the surface and above the thermocline. The maximum concentration of chi. a in October was four times higher than in August. It was notable to measure relatively high concentration of chi. b up to 190.8 ng/1 in the study area, since chi. bcontaining green algae and prochlophytes have been ignored because of their minute size and sensitivity to common preservatives. Major carotenoids detected were fucoxanthin, zeaxanthin, 19'-hexanoyloxyfucoxanthin, and prasinoxanthin. Diatoms were the dominant group with secondary important groups as pryrnnesiophytes and cyanobacteria for the biomass of phytoplankton for both cruises. The dominant species of diatoms in summer were Thalassiosira sp. and Chaetoceros peruvianus. As minor groups, prasinophytes, crysophytes, and cryptophytes were confirmed by their marker pigments and dinoflgellates by microscopical observation. Degradation products of chi. a was minor. Interestingly, at 200 m depth of St A4, the deepest station in the western channel of the Korea Strait, substantial amounts of chi. a including fucoxanthin, 19'-hexanoyloxyfucoxanthin, chi. b, and degradation products of chi. a was measured from both cruises. Higher concentration (2-3 times) of those pigments were detected from samples in summer than in autumn. Small decrease in concentration of phosphate at this depth of St. A4 was also observed. It suggested that this bottom cold water was transported from the subsurface water with biomass of active phytoplankton, which was sunk and flowed southward.

• 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.

• Ocean and Polar Research
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• v.23 no.3
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• pp.245-253
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• 2001

To investigate the community structures and the their seasonal variation of phytoplankton and zooplankton, a study was conducted at 6 selected stations during the period from April 1999 to October 2000 in the marine ranching ground off Tongyeong. One hundred ninety species of phytoplankton were identified, including 146 diatoms, 38 dinoflagellates, 4 silicoflagellates and 2 euglenophytes. Phytoplankton standing crops varied extensively by months and stations, ranging from $3.0{\times}10^4\;cells/l\;to\;1.0{\times}10^6\;cells/l.$. The dominant species varied from the vertical distribution as well as seasonal changes. In April and July 1999, Skeletonema costatum and Ceratium fusus were predominant in both the surface and the bottom water columns. Leptocylindrus danicus was the dominant species in April and June 2000, and Thalassiosira spp. were also predominant in bottom waters in June 2000. Pseudonitzschia pungens and Chaetoceros spp. were the dominant species at both surface and near bottom waters in August and October 2000, respectively. Zooplankton abundance was comparatively high in April and July in 1999, and April, June, and October in 2000, but extremely low in November 1999. The density of dominant zooplankton was higher in 2000 than in 1999. Copepods were the most predominant group except for July 1999 when the bivalve larvae showed extremely high abundance. Acartia omorii and Oithona similis were the dominant or subdominant copepod species mainly in April 2000, and June/July, while O. davisae and O. plumifera had peaks in August and October 2000. Corycaeus affinis and Paracalanus sp. also showed higher peaks in April and June (or July), even though they occurred in all sampling time. Centropages abdominalis occurred abundantly only in April 1999. Oikopleura dioica, a gelatinous zooplankton, was another important zooplankton, showing high density in all samples except in July 1999.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.1
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• pp.37-46
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• 2016

This study describes the spatio-temporal distributions in phytoplankton community such as species composition, standing crops and dominant species from April to November 2008 in the Uljin Marine Ranching Area (UMRA). A total of 123 species of phytoplankton belonging to 67 genera was identified. In particular, diatoms and dinoflagellates were occupied more than 60.5% and 34.6% of total species, respectively. The annual dominant species were Thalassiosira sp., Pseudo-nitzschia pungens in spring, Leptocylindrus danicus, Guinardia striata in early summer, Cheatoceros cirvisetus, Ch. decipiens in early autumn and Skeletonema costatum -ls (like species), Pn. pungens in autumn. Phytoplankton cell density fluctuated with an annual mean of $48cells{\cdot}mL^{-1}$ between the lowest value of $1.8cells{\cdot}mL^{-1}$ in early autumn and the highest value of $240cells{\cdot}mL^{-1}$ in spring. According to the cluster analysis, the phytoplankton community of the UMRA was characterized by the nutrient supply from land side and water movement as current.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.441-453
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• 2017

This paper described the spatio-temporal distributions in the phytoplankton community, such as species composition, standing crops, and dominant species, from July 2012 to April 2013 in the Coastal Waters of Central South Sea (CWoCSS) of Korea. A total of 87 species of phytoplankton belonging to 52 genera were identified. In particular, diatoms and phytoflagellates comprised more than 62.1% and 37.9% of the total species, respectively. The phytoplankton cell density fluctuated with an annual mean of $7.9{\times}10^4cells{\cdot}L^{-1}$ between the lowest value of $1.0{\times}10^3cells{\cdot}L^{-1}$ in spring and the highest value of $4.5{\times}10^5cells{\cdot}L^{-1}$ in winter. The seasonal succession of the dominant species were Chaetoceros curvisetus, Ch. debilis in summer, Eucampia zodiacus in autumn, E. zodiacus, Thalassiosira curviseriata in winter and Skeletonema costatum -ls (like species), Leptocylindrus danicus in spring. According to principal component analysis, the phytoplankton community of the CWoCSS was characterized by the mixing rate between the freshwater inflow from Somjin River and the seawater of the South Sea, Korea.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7761-7772
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• 2015

This study describes the spatio-temporal distributions in phytoplankton community such as species composition, standing crops and dominant species from April to November 2008 in the Jeju Marine Ranching Area (JMRA). A total of 106 species of phytoplankton belonging to 63 genera was identified. In particular, diatoms and dinoflagellates were occupied more than 61% and 35% of total species, respectively. The annual dominant species were Skeletonema costatum-like species(ls) in April, Torodinium teredo, Cylindrotheca closterium, Scrippsiella trochoidea in June, S. costatum - ls, Thalassionema nitzschioides, Pseudo-nitzschia pungens, Ebria tripartita in September and Corethron pennatum, Dictyocha fibura, Neoceratium teres in November. Phytoplankton cell density ranged between $0.6cells{\cdot}mL^{-1}$ in June and $64.0cells{\cdot}mL^{-1}$ in April. It fluctuated with an annual mean of $11.7cells{\cdot}mL^{-1}$ between the lowest value of $0.9cells{\cdot}mL^{-1}$ in November and the highest value of $37.0cells{\cdot}mL^{-1}$ by S. costatum -ls in April. Diversity index in September was higher than diatom blooming seasons in April. According to the phytoplankton community structure, the biological oceanographic characteristics of the JMRA was characterized by nanoplankton during a year. That is, primary production is deemed to have a higher possibility of being adjusted by a reproduction by material cycle in the ecosystems than nutrients supply from the lands.

• Ocean and Polar Research
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• v.34 no.2
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• pp.111-123
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• 2012

To understand the phytoplankton community in the eastern part of the Yellow Sea (EYS), in the summer, field survey was conducted at 25 stations in June 2009, and water samples were analyzed using a epifluorescence microscopy, flow cytometry and HPLC method. The EYS could be divided into four areas by a cluster analysis, using phytoplankton group abundances: coastal mixing area, Anma-do area, transition water, and the central Yellow Sea. In the coastal mixing area, water column was well mixed vertically, and phytoplankton was dominated by diatoms, chrysophytes, dinoflagellates and nanoflagellates, showing high abundance ($>10^5\;cells\;l^{-1}$). In Anma-do coastal waters characterized by high dominance of dinoflagellates, high phytoplankton abundance and biomass separated from other coastal mixing area. The southeastern upwelling area was expanded from Jin-do to Heuksan-do, by a tidal mixing and coastal upwelling in the southern area of Manjae-do, and phytoplankton was dominated by benthic diatoms, nanoflagellates and Synechococcus group in this area. Phytoplankton abundance and biomass dominated by pico- and nanophytoplankton were low values in the transition waters and the central Yellow Sea. In the surface of the central Yellow Sea, high dominance of photosynthetic pigments, 19'-hexanoyloxyfucoxanthin and zeaxanthin implies that haptophytes and cyanobacteria could be the dominant group during the summer. These results indicate that the phytoplankton communities in the EYS were significantly affected by the formation of tidal front, thermal stratification, and coastal upwelling showing the differences of physical and chemical characteristics during the summer.

• Journal of Life Science
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• v.24 no.5
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• pp.532-542
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• 2014

This study describe seasonal patterns in the variation of phytoplankton frequency in the water surface and basal layers and their spatial distributions at seven stations in Hwadang-ri, Goseng-gun in 2013. The phytoplankton community at Hwadang-ri was very diverse, with 60 taxa identified, representing three classes. Diatoms (Bacillariophyceae) exhibited the greatest diversity, with 41 taxa identified. These were followed by the dinoflagellates Dinophyceae, Cryptophyceae, and Eugenophyceae, with 16 taxa, two taxa, and one taxon, respectively. Water surfaces were shown with the relative individual density or abundance across areas. Except in January, Shannon-Weaver indices of diversity of the water surface layer were lower than those of the basal layer. In addition, evenness indices of the basal layer were higher than those of the water surface layer, except in January. For the community as a whole, the values of ${\beta}$-diversity were low for the seven stations: 1.125 for the water surface layer and 1.481 for the basal layer. Seasonal values for ${\beta}$-diversity were similar at the seven stations: 1.725 for the water surface layer and 1.347 for the basal layer. The phytoplankton community showed high taxonomic homogeneity in all four seasons, in addition to similar trends in seasonal development at depths in the same stations. However, the size distribution of the abundance and biomass showed a statistically significant west-east difference.