• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.340-354
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• 2021

The aim of this study was to investigate the spatial and temporal distribution of phytoplankton biomass and community composition in Jinhae Bay on the southern coast of Korea. Phytoplankton pigment analysis was conducted using ultra performance liquid chromatography (UPLC) were conducted from April to December 2019 at seven stations. Temperature, salinity, and dissolved oxygen (DO) and inorganic nutrients (dissolved nitrogen, dissolved phosphorus, and orthosilicic acid) were measured to investigate the environmental factors associated with the structure of phytoplankton community. Phytoplankton biomass (Chl-a) was the highest in July (mean 15.4±4.3 ㎍/L) and the lowest in December (mean 3.5±0.6 ㎍/L). Fucoxanthin was the most abundant carotenoid and showed a similar variation pattern to Chl-a, peridinin, and Chl-b. Phytoplankton community composition analysis showed that diatoms were a predominant group with an average abundance of 70 % whereas chlorophytes, cryptophytes, and dinoflagellates often appeared with lower averages. Further, the dominance of diatoms was closely correlated with water temperature and N:P ratio, which might be influenced by high temperatures in the summer and nutrient loading from the land. Additionally, freshwater and nutrient input by rainfall was estimated to be the most important environmental factor. Hence, the spatial and temporal variations in the composition of phytoplankton pigments and phytoplankton community were correlated with physicochemical and environmental parameters.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.232-241
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• 2009

The dynamics of phytoplankton communities were investigated for Upo wetland from march 2005 to December 2007 on monthly basis. During the investigation, totally 213 phytoplankton taxa which belonged to 86 genera of 35 families in 8 classes were observed. Chlorophyceae was the most diverse in the Upo wetland. Number of phytoplankton taxa was in the range 14${\sim}$50 for monthly investigation and the average number of taxa was 34${\pm}$10. Phytoplankton standing crops were the lowest value of 161 cells $mL^{-1}$ in August 2005 and the highest with 159,283 cells $mL^{-1}$ in August 2006. Especially during summer season in 2006, phytoplankton standing crops showed the highest value due to the waterbloom occurred by cyanobacteria. The number of the dominant taxa of Upo wetland were 13 and among them chlorophyceae and cyanophyceae dominated 8 times. In the view of seasonal changes of phytoplankton community, Upo wetland had high portion of cryptophyceae, dinophyceae and bacillariophyceae in the winter season and chlorophyceae and bacillariophyceae in the other season. However, in the summer season of 2006, cyanobacteria showed the highest portion. The diversity indices had range from 0.50 to 2.86 and showed the tendency of gradual decrease in each year.

• 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.

• Ocean Science Journal
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• v.40 no.3
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• pp.109-117
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• 2005

Daily changes in phytoplankton abundance and species composition were monitored from July to September 2003 (n=47) to understand which factors control the abundance at a station in Jangmok Bay. During the study, the phytoplankton community was mainly composed of small cell diatoms and dinoflagellates, and the dominant genera were Chaetoceros, Nitzschia, Skeletonema and Thalassionema. Phytoplankton abundance varied significantly from $6.40{\times}10^4$ to $1.22{\times}10^7$ cells/l. The initially high level of phytoplankton abundance was dominated by diatoms, but replacement by dinoflagellates started when the NIP ratio decreased to <5.0. On the basis of the N/P and Si/N ratios, the sampling periofd could be divided into two: an inorganic silicate limitation period (ISLP, $14^{th}$ $July-12^{th}$ of August) and an inorganic nitrogen limitation period (INLP, $13^{th}$ of August - the end of the study). Phosphate might not limit the growth of phytoplankton assemblages in the bay during the study period. This study suggests that phytoplankton abundance and species composition might be affected by the concentrations of inorganic nutrients (N and Si), and provides baseline information for further studies on plankton dynamics in Jangmok Bay.

• 한국해양학회지
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• v.30 no.3
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• pp.163-169
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• 1995

A total of 190 phytoplankton taxa was identified in southern waters of the East Sea of Korea in May 1988, July 1989 and November 1991. Leptocylindrus danicus, Nitzschia pungens and Bacteriastrum delicatulum were the dominant species in spring. In summer, Skeletonema costatum was dominant all around the study area but Chaetoceros socialis and Rhizosolenia alata f. gracillima were locally dominant. On the other hand, the dominant species in autumn shifted to Chaeotoceros socialis, Nitzschia delicatissima, Nitzschia sp. and Gymnodinium sp. The average species diversities of the phytoplankton community were low in spring, summer and autumn, being 1.24, 1.69 and 2.12 respectively. The result of cluster analysis in summer suggested that the surface water of this study area could be divided into three phytohydrographic regions which consisted of the oceanic water region affected by Tsushima current, the east Korean neritic water region and the proper water region adjacent to Ulleung island. Compared with the surface phytohydrographic regions, one more region might be recognized at the 40m depth waters. It was appeared in the middle of study area and seemed to be affected by both Tsushima current and water mass of 10$^{\circ}C$ located deeper than 50m.

• ALGAE
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• v.20 no.2
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• pp.133-140
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• 2005

Daily variation of phytoplankton community and environmental parameters were investigated at the lower Nakdong River (Mulgum) from January 2002 to December 2003 to investigate the dynamics of a phytoplankton community in detail. The daily results of water quality in this investigation showed pH (8.1 $\pm$ 0.7), DO (10.3 $\pm$ 2.7 $mg{\cdot}l^{-1}$), water temp. (18.8 $\pm$ 7.4°C), BOD (2.4 $\pm$ 1.0 $mg{\cdot}l^{-1}$), COD (5.3 $\pm$ 1.2 $mg{\cdot}l^{-1}$) and chl. a (43.5 $\pm$ 35.1 mg ${\cdot}m^{-3}$). The results of nutrient factors were the following: TN (3.1 $\pm$ 0.8 $mg{\cdot}l^{-1}$), NO3-N (2.5 $\pm$ 0.5 $mg{\cdot}l^{-1}$), TP (90 $\pm$ 48 ${\mu}g\;{\cdot}\;l^{-1}$), PO4-P (43 $\pm$ 30 ${\mu}g\;{\cdot}\;l^{-1}$). Dominant phytoplankton species during the study period were diatom (Stephanodiscus hantzschii, Aulacoseira granulata var. angustissima and A. italica) and cyanobacteria (Microcystis aeruginosa, Aphanizomenon flos-aquae). The small centric diatom, Stephanodiscus hantzschii, was repeatedly dominant from late fall to the following spring (mean and maximum cell density, 2.3 × 103 $\pm$ 3.8 × 103, 4.5 × 105 cells $ml^{-1}$, respectively). Pinnate diatom, Aulacoseira granulata var. angustissima and A. italica, were frequently observed all season except January to March. Cyanobacteria, Microcystis aeruginosa and Aphanizomenon flos-aquae, proliferated in summer of 2002 except in 2003 due to heavy precipitation. The dominant zooplankton species (March-early May) was rotifer (Brachionus, Keratella, Polyarthra) and cladocerans (Diaphanosoma). The daily observed dynamics of the phytoplankton community in the lower Nakdong River in this study may play an important role in increasing the detailed resolution of limnological information and serving as ecological data for future studies.

• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.317-325
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• 2010

This study was to investigate phytoplankton communities and to evaluate the effects of hydrological and physical-chemical environmental factors in major five dam reservoirs in the Han River water system. Annual average of chlorophyll a concentration in Lake Paldang, Lake Cheongpyeong and Lake Doam was higher than that of Lake Chungju and Lake Hoengseong. The opposite seasonal variation patterns of phytoplankton growth were observed in dam reservoirs; the highest biomass in spring of dry season in Lake Paldang, Lake Cheongpyeong which are the river-type reservoirs and Lake Doam where turbidity was high throughout the year, and in summer and autumn of rainy season in Lake Chungju and Lake Hoengseong which are the lake-type reservoirs, indicating that the seasonal pattern for growth of phytoplankton in on-river reservoirs is mainly determined by hydrologic characteristics. The dominant species of phytoplankton in Lake Paldang, Lake Cheongpyeong and Lake Doam, where the concentration of nutrients was relatively high, were Bacillariophyceae such as Stephanodiscus hantzschii, Aulacoseira granulata var. angustissima in Lake Paldang and Lake Cyeongpyeong and Nitzschia spp. in Lake Doam throughout all season. The dominant species of phytoplankton in Lake Chungju and Lake Hoengseong which showed the oligo-mesotrophic state, were Bacillariophyceae such as Stephanodiscus hantzschii, Cyclotella pseudostelligera in spring and winter, but Cyanophyceae such as Microcystis spp. in summer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.579-592
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• 2020

This study was designed to assess the water quality and phytoplankton community including chlorophyll a in blood cockle (Tegillarca granosa) farms in May, August and November of 2017 in the northwestern Yeoja Bay, Korea. As a result, the seasonal characteristics of water types by water temperature and salinity were clear. Nutrients were abundant in silicate throughout the season, but phosphate was scarce in spring and summer, and nitrogen sources were scarce in autumn. The species composition of phytoplankton community was a very simple distribution, and the standing crop was also very low. The annual dominant species is dominated by the diatoms, with Skeletonema costatum-ls, Nitzschia longissima in spring, Pleurrosigma normanii, Coscinodiscus gigas in summer, and N. longissima, Pseudonitschia pungens, Chaetoceros curvisetus, Eucampia zodiacus in autumn. In summer the results were different from other coastal waters of Korea. The principal component analysis(PCA) and correlation analysis showed that the characteristics of water quality and biological environments differed according to the season. Furthermore, it was determined by the supply of materials through fresh water on land, seawater congestion caused by the refueling of surface sediments with lower depth, and the balance of biological production and mineralization of organic matters in blood cockle farms.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.95-115
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• 1999

The dynamics of phytoplankton community in Lake Imha and its tributaries was investigated at nineteen stations in August and September 1996. A total of 171 taxa ［171 species (including 1 forms and 27 varieties),66 genus, 25 families, 6 suborders, 13 orders and 6 class］ were identified. The standing crops of phytoplankton ranged from $47.35{\times}10^3 to 184.65{\times}10^3 individuals/ml in surface layer, 1.08{\times}10^3~54.33{\times}10^3 individuals/ml in middle layer and 0.69{\times}10^3~115.85{\times}10^3individuals/ml$ in low layer. Dominant species determined by standing crops of each species were Oocystis lacustris, Elakatothrix gelatinosa, Aulacoseira ambigua, and Synedra acus, however, the most species dominated from 1992 to 1994 disappeared.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.4
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• pp.158-165
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• 2010

Phytoplankton community structure is one of the indicators that can explain the enviromnental characteristics of coastal waters. In this study, phytoplankton community structure and water quality of aquaculture area were investigated for understanding regional enviromnental characteristics. Thirty stations in aquaculture areas of Tongyeong, southeast coast of Korea, were investigated monthly from January to December, 2009. Phytoplankton community, meteorologic dada and enviromnent factors including temperature, salinity, transparency, nutrients and chlorophyll a were also examined. Chaetoceros spp. and unidentified small flagellates were dominant species in all the year round. Pseudo-nitzschia spp., Dictyocha spp., and Nitzschia longissima were dominant in June to October being summer season, and Skeletonema costatum, Thalassiosira spp., Eucamphia zodiacus, Akashiwo sanguinea, Gymnodinium spp. and Asterionella japonicus appeared as dominant species in the rest of months. Dinoflagellate blooms occurred 3 times in near Hansan Bay and around Saryang-do, and the highest chlorophyll a was found in Hansan Bay. Species diversity of phytoplankton was lower in Hansan and Womnum Bay, and diatom was more abundant than dinoflagellates in Mireuk-do waters. These results showed that phytoplankton community varied by the seasonal and geographical characteristics, and recent increase of water temperature and heavy rain may affect on phytoplankton community structure.