• Ocean and Polar Research
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• v.28 no.3
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• pp.305-315
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• 2006

In order to examine the transition of zooplankton community by the Saemangeum sea dyke, the temporal and spatial distribution of zooplankton community with relation to environmental variables was investigated using data collected in 2004 and 2005. Sixty-one zooplankton taxa were identified. Average abundance (except Noctiluca scintiliam) ranged from 236 to 1810 indiv. $m^{-3}$, and was the highest in May 2005 and the lowest in february 2005. Dominant species were Acartia hongi and Paracalanus indicus, and cirripedia nauplii and zoea were dominant groups. After the closure of the 4th sea dyke, brackish species such as Tortanus derjugini and Pseudodiaptomus inopinus are widely distributed while the abundance of N. scintillans decreased in the northern area inside the dyke. In canonical correspondence analysis (CCA) for examining the relationships among zooplankton, stations and environmental variables, the northern area inside the dyke was distinguished from the other areas and was represented by Acartia spp, and brackish copepods.; Also, this area was characterized by high chlorophyll a concentration and COD, and low diversity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.2
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• pp.154-170
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• 2022

The zooplankton composition, abundance, community structure, and species diversity in the major commercial fishery species spawning grounds in the southern coast of Korea were investigated in this study. A total of 80 taxa were sampled, with the mean abundance range of 5,612-11,720 ind. m^-3 and the mean biomass range of 41.6-1,086.8 mg m^-3. The dominant species were Paracalanus copepodites, Paracalanus parvus s. l., Oithona copepodites, Paracalanus nauplii, Noctiluca scintillans, Oithona similis, and Ditrichocorycaeus affinis. The species diversity indices were highest in August, suggesting that diversity is influenced by neritic and oceanic warm-water species. A cluster analysis with non-metric multidimensional scaling (nMDS) revealed three groups of zooplankton communities. The April and May samples clustered into Group A, having the highest mean total zooplankton abundance and lowest species diversity, consisting mainly of temperate species located in the middle region of the southern coast of Korea. Cluster Group B was from the early summer season (June) and contained the highest species diversity with some oceanic and neritic zooplankton species. Cluster Group C from the summer season (July and August) mainly comprised P. parvus s. l. and O. similis. The redundancy analysis (RDA) indicated that abundance is positively correlated with salinity, and chlorophyll-a concentrations.

• Korean Journal of Environmental Biology
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• v.33 no.1
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• pp.19-26
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• 2015

Pre-monsoon dynamics of zooplankton community were investigated in the estuary of the Tamjin River flowing into the Doam Bay of the southern coast of Korea. Monthly sampling was carried out to collect zooplankters at five sites in the estuary and the river during the period between March and June 2014. Dissolved oxygen contents were low between $5.0{\sim}7.0mgL^{-1}$ in the estuary and high, 7.0~11.0, in the river. Water temperature increased gradually from 12.0 to $28.0^{\circ}C$ and pH fluctuated between the range 7.4~8.8, respectively. A total of 85 taxa consisted of 25 species of rotifer, 30 kinds of copepod, 8 species of cladoceran, six kinds of aquatic insect larvae, four kinds of decapod and two kinds of Cirripedia larvae and Polychaeta larvae and one kind of Amphipoda, Ispopoda, Appenidicularia, Nematoda and Cnidaria, and Nocticluca scintillans was occurred. Brackish copepods distributed at almost all studied sites with freshwater zooplankters being restricted to upper waters of the river. Monthly succession of Acartia spp. was observed in the estuary with the occurrence of A. hudsonica in March and April then A. omori in May and June. Zooplankton abundance showed to vary from 450 to $87,818ind\;m^{-3}$ due to the explosion of copepodite and copepod nauplius in the estuary. Species diversity indices varied between 0.6~2.3 and generally low in the estuary and high in the river. Sea water input into the river seems to affect the river biota for more than some kilometers of the upper waters of the Tamjin River.

• Korean Journal of Environmental Biology
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• v.22
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• pp.11-29
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• 2004

This study was conducted bimonthly from June 2001 to June 2003 to investigate the seasonal variation of the zooplankton community in Gwangyang Bay, Zooplankton were collected at 9 stations using a NORPAC net from surface layer. The zooplankton community consisted of 47 taxa and the mean abundance was 6,205 inds. $m^{-3}$ during the survey period. The maximum abundance was observed to be 20,060 inds. $m^{-3}$ in June 2002 and the minimum in August 2001 with 630 inds. $m^{-3}$. Copepods were the predominant constituent, wihich comprised 4.6~84.1% (mean 38.2%) of the total zooplankton abundance. Dominant species of copepods were Acartia omorii, Acartia erythraea, Centropages abdominalis, Paracalanus parvus. Paracalanus parvus dominated from June 2001 to December 2002. A red tide causative dinoflagellate, Noetiluca scintillans, dominated from June 2002 to February 2003, Acartia omorii and Centropages abdominalis dominated in winter and spring seasons. While, Acartia erythraea dominated in summer and fall seasons. In June and August, Cladocerans and Cirriped larvae dominated. The abundance of zooplankton according to the tidal cycle showed considerable fluctuations with a range of 2,768~15,856 inds. $m^{-3}$ $(\risingdotseq$ 5.7 times).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.4
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• pp.1-20
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• 1986

Physical, chemical and biological surveys on Nakdong River estuary were made from October, 1985 to September, 1986. 1. For all the seasons except summer, the sea surface temperature in northwest area of the line which linked from Seo Island to Jisim Island was I-2$^{\circ}$C lower than in southeast area, but in summer the sea surface temperature in northwest area was I-2$^{\circ}$C higher than in southeast area. On the contrary, bottom temperature of coastal area was 1$^{\circ}$C higher than that of oceanic area except winter. 2. Surface salinity in summer and fall has minimum value of 1. 9%0 and maximum value of 32.9%0. This large variation was caused by the runoff of the Nakdong River. Effect of less saline Nakdong River water in northwest area of the line which linked from Seo Island to Jisim Island was greater than in southeast area. A strong current rip always formed near this line. 3. The yellowish-green colored zone was observed in the Nakdong River estuary throughout the year by influence of river discharge. The characteristics of the water quality in the zone have shown that the water color was grade 7 by the Forel water-color meter, transparency was less than 4 m, and concentration of suspended solids was more than 5 mg/1. This water body was in the state of eutrophication in terms of chlorophyll-a and inorganic nitrogen concentration during summer season. 4. During the study period, total 276 taxa were identified. Most of them were diatoms and dinoflagellates which consisted of 97.5%. The component ratio of the above two groups was 84.4% and 13.1 % respectively. Diatoms were plentiful in December and dinoflagellates in July. Dominant species were Nitzschia seriata in October, Thalassiosira rotula in December, Skeletoncma costatum in April, and Nitzschia longissima in July. 5. A total of 47 zooplankton taxa was identified from the samples collected. Copepods were numerically the most important components of zooplankton communities in the study area. The domir:ant copepod species were Paracalanus parvus, Acartia clausi and Temora turbinata. Noctiluca scintillans was the next important component. The other zooplankton with minor abundance were Cladocera. Sagitta spp., Cnidaria, Mysidacea, Lucifer spp. and Amphipoda. 6. During the study period, fishes from 47 families and 87 species were sampled in th~ study area. The four most abundant fish species were Rep~mucen//'s valencicnnei, Leiognathus n~cha!is, Amblychaeturicllthys hexanema and Sardirel/a zun:zsi. The fish species of the secondary importance in abundance were Cynoglossus joyneri, Sillago sihama, Engra~lis japonicus, Encdrias nebulos'l, Acanthogobius flavimanus, Trichiurus lepturus, LiParis tanai/ai, Cynagloss//'s interruptus, Aj)ogon line:z!us, Thrissz la 1l.'1la!ensis, and Limanda yokohamac.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.1-11
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• 2020

This study investigated the mesozooplankton community and the related environmental factors in the Nakdong River Estuary in May and early October shortly after passage of the typhoon "DUJUAN" in 2015. The mesozooplankton community was dominated by barnacle nauplii, foraminiferans, and Noctiluca scintillans, and the environmental characteristics were characterized by freshwater inflow through the Nakdong River barrage, the intrusion of warm currents, and the effect of typhoon passage in October. In May, cladocerans, such as Evadne nordmanni and Podon polyphemoides, as indicator species of brackish water, prevailed throughout the study area. The surface salinity was lowest on the inner side of the barrier-islands and increased gradually to the outer side during the study. The average concentration of total suspended solids in October was higher than that in May, while the averaged concentration of nitrate and chlorophyll-a in May was higher than those in October. On the other hand, there was no temporal difference in the total averaged abundance of mesozooplankton. In contrast, the distributional pattern of the mesozooplankton community was associated with the salinity gradient in both seasons. These results suggest that the temporal difference of the mesozooplankton community depended on the extent of freshwater inflow by barrage opening, the intrusion intensity of warm currents, and typhoon passage in the Nakdong River estuary in 2015.

• Korean Journal of Remote Sensing
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• v.33 no.2
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• pp.213-230
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• 2017

The satellite-based red tide detection algorithms have been developed for specific occurrence waters and red tide species. However, it is essential to study the whole occurrence waters and various red tide species for quick and accurate surveillance of red tide around the Korean coastal waters. In thisstudy, the comprehensive analysesinvolve the spectral features of red tide areas and the suitability of the satellite-based red tide detection algorithms used with GOCI in the Korean coastal waters. As a result, the spectral characteristics were changed according to the chlorophyll content of red tide species and the turbidity of the waters where the red tide appeared. In addition, the previous red tide detection algorithm is applied to GOCI, and it is found that there is a limitation to the red tide area extraction as the existing threshold value. To overcome these limitations, red tide species were divided into two groups according to the difference of chlorophyll content and a system for red tide surveillance wassuggested. It is possible to distinguish between red tide and non-red tide area through five steps. As a result of applying to GOCI, the red tide was appropriately extracted from the previous algorithm based on red tide breaking news. If such a red tide surveillance system is used, it will be possible to efficiently monitor red tide by quick and accurate surveillance of the whole occurrence waters around the Korean and various red tide species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.4
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• pp.415-430
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• 1996

Spatio-temporal variations in zooplankton community and ropepod indicator species were investigated along with the interaction between zooplankton distribution and environmental factors in Chinhae Bay. Zooplankton samples were monthly collected at 7 stations from February to September in 1993. A NORPAC net was vertically hauled from bottom to surface, At the same station, environmental factors such as temperature, salinity and COD (chemical oxygen demand) were measured at two different water layers, surface and bottom. In August and September, salinity declined below 30.00‰ , while eutrophic parameters such as COD showed the higher concentrations than those in other months, with higher concentrations at inner bay stations. Salinities were, however, higher at bay mouth areas. These distributional patterns were believed to be caused by input and dispersion of organic matters from nearby land. Zooplankton communities were composed of 7~14. Of these, Noctiluca scintillans was predominant and occupied 90.6‰ of total zooplankton abundance. Cladocera and Copepoda were secondly abundant taxa. Among 6 to 10 copepod species appeared, Acartia omorii and A. hudsonics were most common species during the survey months except March and September. Species diversities were greater, in general, at inner bay than outer bay. The lowest diversity index was observed in February, while the highest in July. Cluster analysis could divide the study area into 2 or 4 zones for each month. Zone 1, mouth area of the bay, was characterized by the influence of offshore waters. Zone II was mixing area. Zone III and IV seemed to be affected by nearby land.

• 한국해양학회지
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• v.29 no.2
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• pp.132-144
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• 1994

The relationship of zooplankton communities and distributions of copepods as indicator species to environmental variables, such as temperature, salinity, chemical oxygen demand (COD) and total inorganic nitrogen (TIN) was studied in Pusan Harbor in October 1990 and January, April and July 1991. Zooplankton communities were analysed by using cluster analysis and species diversity index. Four groups of copepods as indicator species were Acrocalanus gacilis, Euchaeta plana, pareuchaeta russell and Pleuromamma gracilis as the oceanic warm water species; Cemtropages abdominalis as the neritic cold water species; Meridian lucens as the oceanic cold water species Acartia omorii as the polluted water species. the offshore waters of Pusan harbor was dominated by the oceanic warm water species in October and by the neritic cold water species in January and April. This area showed the low values of COD and Tin. the inshore waters of Pusan harbor, where the high values of cod And Tin and the low value of diversity were recorder was represented by A.. omorii. Cluster analysis of the zooplankton community revealed two or three regional areas in Pusan harbor. Area I, the offshore area of Pusan harbor, not only was represented high species diversity and low density of A. omorii but also was dominated copepods in zooplankton roups. Areas II and III were grouped horizontally from offshore to inshore of Pusan harbor. Area II was showed intermediate values in diversity, density of A. omorii and percentage composition of copepods. Area III was revealed the lowest diversity,density of A.omorii and percentage composition of Cladocerans.Coperpoda was a dominant zooplankton group in each area during the study periods except two special cases.Area II was dominated by Noctiluca scintillans in April and Area III was occupied by Cladocerans in July.Distribution of Indicator species and areas demarcated based on cluster analysis showed a close relationship with environments.

• 한국해양학회지
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• v.26 no.3
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• pp.181-192
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• 1991

Zooplankton were sampled horizontally with a standard net from the surface layer of the estuarine system of Mankyong River and Dongjin River in October, 1989, March, May, and July, 1990. Among dominant taxa of the zooplankton community, copepods were predominant in October, 1989 and March, 1990 and Noctiluca scintillans in May and July, 1990. Abundance of zooplankton showed considerable spatial and temporal fluctuations with a range of $12~9,256ind./m^3$ in wet weight. In the copepod community, Pseudodiaptomus inopinus and Paracalanus inducus were predominant in October, 1989: Acartia hudosonica and P. inducus in March, 1990; A. hudosonica and Centropages abdoinalis in May, 1990; A. pacifica, P. indicus and Tortanus spinicaudatus in July. 1990. In summer (July),there were large seasonal changes in salinity ($0.7~28.9\textperthousand$), due to monsoonal flooding, and associated changes in community structured of copepods. There were eight species of copepods in the mixo-mesohaline zone ($5.0~28.8\textperthousand$), namely Acartia pacifica, A. hudosonica, Centropages tenuiremis, C. abdominalis, Labidocera Euchaeta, Tortanus spinicaudatus, corycaeus affinis and Paracalanus indicus. On the other hand, Thermocouple hyalinus, Pseudodiaptomus inopinus and Sinocalanus tenellus occurred in the mixo-oligohaline zone ($0.5~5.0\textperthousand$), showing more tolerant of low salinity than any of the other species. In the mixoeuhaline zone ($>28.0\textperthousand$), Labidocera bipinnata, Oithona similes, Calanus sinicus, Acartia omorii and Tortanus forcipatus were founded.