• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.422-430
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• 2016

We investigated the abundance and composition of the zooplankton community around Dokdo in the East Sea from 2006 to 2015. Zooplankton samples were collected in the surface mixed layer by vertical hauls using a standard type net at the monitoring stations. There were no clear long-term trends in the average temperature and salinity, but relatively low salinity was recorded in the summer of 2013 and 2015. The average abundances of zooplankton in the summer increased by two orders of magnitude from $317inds./m^3$ in 2008 to $10,242inds./m^3$ in 2015. This long-term increase was accompanied by a slight increase in the chlorophyll-a concentration and a decrease in the catch of potential crucial predators (anchovy, mackerel pike, squid, herring and horse mackerel) in the study area. The dominant zooplankton, accounting for most of the long-term increase, consisted of appendicularian (Oikopleura spp.), which showed a steady increase since 2012, summer species such as Noctiluca scintillans and the cladoceran Penilia avirostris, which showed an abrupt increase, and the copepod Paracalanus parvus s.l., which showed a rapid increase after its first occurrence in summer 2010. These results suggest that the long-term increase of zooplankton could be related to the increase in the concentration of prey and the decrease in the predation pressure of potential predators around Dokdo in the study area.

• Korean Journal of Ecology and Environment
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• v.54 no.3
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• pp.156-169
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• 2021

Traditional morphological identification difficulties, such as phenotypic plasticity, misidentification of cryptic species, and larval stage species, can be compensated for by using DNA analysis techniques, such as DNA barcoding, in surveying zooplankton populations, including species identification. Recently, the rapid development of DNA sequencing techniques has allowed DNA-based community analysis not only for zooplankton assemblages in various aquatic ecosystems but also for the gut contents of zooplankton that are limited by conventional methods such as visual and microscopic identification. Therefore, the application of DNA sequencing can help understand biological interactions through the analysis of zooplankton food sources. The present paper introduces the major DNA-based approaches in zooplankton research topics, including taxonomic approaches by DNA barcoding, community-level approaches by metabarcoding, and gut content analyses, summarizes the analysis methods, and finally suggests the methodological topics that need to be considered for future applications.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.337-348
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• 2007

Characteristics in distributions of T, S, nutrients, chlorophyll ${\alpha}$ concentrations and meso-zooplankton abundances and the relations among these parameters were investigated with the data collected in Asan Bay around the rainy season from May 24 till August 25, 2006 at about 10 days interval. Freshwater input during the rainy season clearly affected the distributions of zooplankton and phytoplankton (chlorophyll ${\alpha}$). Freshwater discharge resulted in high nutrients decreased zooplankton abundances. On the contrary, chlorophyll ${\alpha}$ concentrations increased at the end of the rainy season. It seemed that the increase of chlorophyll ${\alpha}$ concentrations was the result of the decreased zooplankton and enriched nutrients caused by freshwater discharges. Seawater temperatures were certainly the reason for the zooplankton succession. However, overall abundance of zooplankton and abundances of some zooplankton such as Noctiluca scintillans, Acartia pacifica, and Sagitta crassa seemed to be influenced by lowered salinity caused by heavy rain rather than seawater temperatures.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.720-734
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• 2023

To understand the spatiotemporal distribution pattern of zooplankton and the environmental factors influencing zooplankton abundance in Gomso Bay, major harvesting area of Manila clam (Venerupis philippinarum) in South Korea, zooplankton sampling was conducted four times in autumn (October 2022), winter (January 2023), early spring (March 2023), and spring (May 2023). Among the environmental factors of Gomso Bay, water temperature, chlorophyll a concentration (Chl-a), dissolved oxygen (DO), and pH observed different patterns, while salinity and suspended particulate matter(SPM) showed no significant statistical differences between the survey periods. The zooplankton in Gomso Bay occurred 33, 29, 27, and 29 taxonomic groups during each respective survey period. In October 2022 and May 2023, arthropod plankton were dominated, while in January and March 2023, protozoa were primarily dominant. Among the Arthropods, copepods including Acartia hongi, Paracalanus parvus s. l., Corycaeus spp., and Oithona spp. commonly found along Korean coastal areas of the Yellow Sea, were dominated. Cluster analysis based on zooplankton abundance indicated a single community (stable condition) in each season, attributed to low dissimilarity distances, while three distinct clusters (autumn, winter-early spring, spring) between seasons indicated a highly seasonal environment in Gomso Bay.

• Korean Journal of Environmental Biology
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• v.33 no.2
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• pp.230-239
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• 2015

Monthly variations of cirriped larvae near Oryuk islets off Busan were investigated at four stations from January 2012 to January 2013. Zooplankton was vertically collected, using NORPAC net (mouth 45 cm, mesh $200{\mu}m$), from the surface to 1 m above the bottom. 12 species belong to five genera of 4 families were identified including one unidentified species. Cirriped larvae occupied small portion of total zooplankton, ranging 0.02 to 4.1% of total zooplankton densities. The densities varied monthly from $1inds.m^{-3}$ to $715.1inds.m^{-3}$, which was highest in September and lowest in February. Chthamalus challengeri, Balanus glanula, B. improbisus, B. nubilus and Octomeris sulcata were dominant species and accounted for 70.1% of total cirriped larvae. Larval densities of cirripeds between stations were not significantly different (F=0.237, p=0.870). The larval communities were grouped into two groups by cluster analysis. We discussed the distribution patterns of cirriped larvae in relation to oceanographic characteristics in the study area.

• Korean Journal of Microbiology
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• v.30 no.2
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• pp.129-133
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• 1992

Zooplankton feeding was investigated with epilluorescence microscope in Lake Soyang in August 1991. Zooplankton. which ingested fluorescence bead or fluorescently labeled bacteria (FLB). was regarded as bacterivore. The algavores wert. easily distinguished with autofluorescence of chlorophyll in gut. Copepoda nauplius and Copepodids. 7'hermocyclop.s spp, Pleosomcl spp. Brachionus spp were algavores. and DuphnB hpp. Bosmincr spp. Kerutrlla spp and Hrxuthru spp werc identified as bacterivc~res.T he mixo\ory was not detected. The percentages of algavores and bacterivores in Lake Hoyang were 65 7% and 34.3%. respectively. The bacterivorous zooplankton had trend to ingcst the beads bigger than 0.5 pm. Use of 0.5 pm bead as grazing tracer gave similar estin~ates of ingestion to FLR.

• 한국해양학회지
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• v.25 no.4
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• pp.229-239
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• 1990

The zooplankton of Chonsu Bay was collected and analyzed to study the seasonal variation in species composition and abundance, and to estimated the total annual production of Copepoda. With a pronounce seasonal fluctuations in species composition and abundance, Paracalanus indicus and Corycaeus affinis predominated during summer and fall, while larger species such as Centropages abdominalis and Acartia dominated in spring. Zooplankton abundance showed the minimum in March, then increased and reached the maximum in August. It is suggested that seasonal variation of zooplankton as well as temperature. Being productive compared with other areas, the estimated total production of Copepoda was 134 g/100m$^3$/yr (dry weight).

• Korean Journal of Ecology and Environment
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• v.35 no.2 s.98
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• pp.141-144
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• 2002

The construction of river mouth dam has prevented seawater from backwarding to upstream in Kum river estuary since 1990. Field observation on environmental factors, and zooplankton and phytoplankton dynamics have been carried out three times with two month interval in the summer and autumn in 2000 at three selected stations in Kum river estuary. Blockade of seawater flowing backward to upstream caused sharp contrast of zooplankton fauna and phytoplankton flora between upstream and downstream of the river mouth dam. Freshwater cladocerans i.e., Bosmina longisrostris and Daphnia galeata dominated in the upstream, and marine copepods of Acartia omorii and Paracalanus crassirostris occurred abundantly in downstream of the dam. Freshwater diatoms did not distributed in the downstream of the dam except Melosira varians, while marine diatom of Cylidrotheca closterium occurred in benthic waters bath in upstream and downstream of the dam. The construction of the river mouth dam seems to play an ecological role to blockade the input of marine organism into the upstream in Kum river estuary.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.60 no.1
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• pp.9-17
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• 2024

In this study, the seasonal distribution was surveyed using acoustic in the coastal waters around nuclear power plants. Acoustic surveys were conducted in June, September, December 2022, and March 2023 in the coastal waters of Uljin-gun. According to the results of this study, zooplankton were distributed at the depths from 0 m to 50 m in the waters around nuclear power plants. Zooplankton appeared in summer (June), autumn (September), and spring (March). In the survey area, fish were distributed at the depths from 25 m to 190 m, appearing in the summer (June), autumn (September), winter (December) and spring (March). The SV of zooplankton appearing in the survey area ranged from -98.0 dB to -78.0 dB, and it exhibited a one-class in the frequency distribution of SV. The SV of fish appearing in the survey area ranged from -36.0 dB to -35.0 dB and -98.0 dB to -53.0 dB, and it exhibited two-class in the frequency distribution of SV.

• 한국해양학회지
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• v.27 no.4
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• pp.268-276
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• 1992

Multitrophic interactions among gelatinous planktivores, zooplankton, and phytoplankton were in vestigated in Reeves Bay. New York from mid-March to July in 1989 to evaluate the top-down effect by gelatinous macrozooplankton on the Gyrodinium aureolum bloom through cascading tropic interactions. Zooplankton abundances reached maximal density following a decrease in gelatinous macrozooplankton (hydromedusae and scyphomedusae) abundances, and phytoplankton biomass was low at this time. Subsequently, as ctenophore populations increased zooplankton abundances decreased sharply, and the cell concnetration of G. aureolum began to increase. This field observation supports that the top-down control by gelatinous macrozooplankton on grazers, resulting in low grazing pressure on phytoplankton, can cause an algal bloom. The minimal zooplankton grazing measured using /SUP 14/C tracer technique during the bloom period indicated that zooplankton did not prefer G. aureolum as a good source.