• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.78-93
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• 2003

To investigate seasonal variation and structure of the microbial community in Kyeonggi Bay, abundance and carbon biomass of nano-and micrzooplankton were evaluated in relation to size fractionated chlorophyll-a concentration, through the monthly interval sampling from December 1997 to November 1998. Communities of nano-and microzooplankton were classified into 4 groups such as heterotrophic nanoflagellate(HNF), ciliates, heterotrophic dinoflagellates(HDF) and zooplankton nauplii. Abundance and carbon biomass of HNF ranged from 380 to 4,370 cells ml-1(average 1,340$\pm$130 cells ml-1) and from 0.63 to 12.4 $\mu\textrm{g}$C 1-1(average 4.35$\pm$0.58 $\mu\textrm{g}$C 1-1), respectively. Abundance and carbon biomass of ciliates ranged from 331 to 44,571 cells ml-1(average 3,526$\pm$544 cells ml-1) and from 1.3 to 119.7 $\mu\textrm{g}$C 1-1(average 13.7$\pm$3.0 $\mu\textrm{g}$C 1-1), respectively. Abundance and carbon biomass of HDF ranged from 88 to 48,461 cells 1-1(average 9,034$\pm$2,347 cells 1-1) and from 0.05 to 54.05 $\mu\textrm{g}$C 1-1(average 6.9$\pm$2.4 $\mu\textrm{g}$C 1-1), respectively. Abundance and carbon biomass of zooplankton nauplii ranged from 5 to 546 indiv. 1-1(average 83$\pm$15 indiv. 1-1) and from 0.17 to 43.2 $\mu\textrm{g}$C 1-1(average 6.3$\pm$1.2 $\mu\textrm{g}$C 1-1), respectively. Eash component of microbial biomass was not different from tidal cycle except tintinnids group. Depth integrated nano-and microzooplankton biomass ranged from 124 to 1,635 mgC m-2(average 585$\pm$110 mgC m-2) and was highest in March and May. The relative contribution of each component to the nano-and microzooplankton showed difference according to seasons. Community structure of nano-and microzooplankton was dominated by planktonic ciliate group. During the study period, carbon biomass of nano-and microzooplankton was strongly positively correlated with size fractionated chlorophylla-a. It implied that prey-predator relationship between microzooplankton and phytoplankton was important in the pelagic ecosystem of Kyeonggi Bay.

• Korean Journal of Ecology and Environment
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• v.46 no.3
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• pp.332-342
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• 2013

We collected zooplankton from May to October, 2011, with the aim of understanding the zooplankton community distribution and food web interaction between the open water and littoral (aquatic plants) zones in two small reservoirs with different land covers (Sobudang, Myeongdong). Small-sized reservoirs are more abundant in South Korea, and a total of 51 and 65 species of zooplankton were identified at the two small reservoir (Sobudang and Myeongdong), where zooplankton densities were more abundant in the littoral zone than in the open water zone. Cladocerans and copepods densities were also higher in the littoral zone, in contrast, rotifers showed higher densities in the open water zone (t-test, P/0.05). Epiphytic zooplankton dominated at the littoral zone (Lecane, Monostyla, Alona and Chydorus) because aquatic plants provided refuge spaces for attachment. Some rotifers (e.g. Brachionus, Keratella and Polyarthra) were more abundant in the open water zone because of their small size, which might help them to go unnoticed by predators. In two-way ANOVA, rotifers related to two reservoirs or habitat space (littoral zone and open water zone), but cladocerans and copepods showed a statistically significant relationship on only two reservoirs. The results of stable isotope analysis showed that zooplankton in the littoral zone tended to depend on organic matter attached to aquatic plants as a food source, which indicates the avoidance of competition of zooplankton with other macro-invertebrates (e.g. Damselfly larva, Cybister brevis and Neocardina denticulate). As a result, zooplankton community distribution is determined by not only habitat space (aquatic plant zone and open water zone) but also by food source (phytoplankton).

• The Korean Journal of Malacology
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• v.28 no.3
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• pp.197-213
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• 2012

This study was performed to know the community structure of macrobenthos and environmental factors at each 16 stations in the subtidal sandy bottoms of the southern coastal water of Jeju Island from July to November, 2011. Mean temperature and mean salinity were $20.2-22.7^{\circ}C$, 33.7-34.9 psu which shows stable water messes. Chlorophyll a concentrations of phytoplankton ranged from 0.71 to 1.71 mg/L (1.11 mg/L), showing higher July than September and November with a blooming in summer. The mean concentration values (the ranges in parentheses) of nitrate, phosphate, and silicate are 0.029-0.206 mg/L (0.101 mg/L), 0.001-0.027 mg/L (0.007 mg/L), 0.024-0.682 mg/L (0.454 mg/L), respectively. However, the values higher coastal zone due to influxes from the land. A total of 37 species was identified. of these mollusca comprised 29 secies (78.4%); Echinodermata 5 (13.5%); Arthropoda 3 (8.1%). density and biomass were estimated to be 550 ind./$m^2$ and 20,951.8 gwwt/$m^2$, respectively. Mollusca were the most dominant faunal group in terms of abundance (481 ind./$m^2$) and number of species as well, whereas bivalves were predominant in biomass (16,647.6 gwwt/$m^2$). The dominant species were Vasticardium burchardi, Oblimopa japonica, Mactar achatina, Bornatemishistrioiw akawai, Paphia vernicosa, Amusium japonicum, Glycymeris albolineata, Astriclypeus manni in 15-30 m. The seasonal variation appeared as distinct, Mollusca of individual and biomass. When summer was make a slow increase, after the highest decrease in autumn. The abundance of macrobenthic invertebrates showed significant correlation with environmental factors (Chlorophyll a, DIN, $SiO_2$, Fine sand, Very fine sand) in almost all sampling depths. The biodiversity, evenness richness index were appeared 1.56-2.50 (H'), 0.49-0.80 (E'), 4.12-4.67 (R) in each stations. The dominace index were appeared Highest in November and lowest in September.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.275-287
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• 2013

The Japanese anchovy Engraulis japonicus is a widespread species in the western North Pacific and major fishery resource. To understand the spatio-temporal variation of anchovy prey items in the coastal waters of southern Korea, the stomach contents of anchovy and the structure of the zooplankton community were analysed at three sites (Jindo, Yeosu and Tong-yeong) from July 2011 to February 2012. The main prey items in Yeosu and Jindo were cyprid stage of barnacle (>35%) and copepod Calanus sinicus (>22%) in July, respectively, while, predominant ones in Tongyeong were small copepods, Paracalanus parvus s.l. (41%) and Corycaeus affinis (22%). During this period, the dominant zooplankton were cladoceran Evadne tergestina (39%) in Yeosu, small copepod, P. parvus s.l. (28%) in Jindo and cladoceran E. tergestina (14%) in Tongyeong. The dominant prey items were barnacle larvae and copepods in summer, phytoplankton and Pseudodiaptomus marinus in autumn and P. parvus s.l. and cold water copepod, Centropages abdominalis in winter. Anchovy prefer the prey item C. sinicus (3%) over E. tergestina (39%), which was a dominant species in the catching site in summer. P. marinus (0.5%) and C. abdominalis (0.9%) were preferred over P. parvus s.l. (30%, 21%) in autumn and winter, respectively. Prey items varied with area and season in the coastal waters of southern Korea. These results suggest that the prey selectivity of anchovy showed high flexibility and adaptability in the study waters.