• Ocean and Polar Research
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• v.30 no.4
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• pp.419-426
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• 2008

Ciliate plankton samples were collected biweekly from July 2006 to June 2008 in Jangmok Bay of Geoje Island. Species composition and abundances were analyzed by quantitative protargol stain and environmental parameters were also examined. A total of 88 ciliate species occurred during the study period, consisting of 22 tintinnids, 51 oligotrichs, and 15 other species. Higher ciliate abundances appeared from June to October during the warm season ($<20^{\circ}C$) and the maximum ($4.0{\times}10^4\;cells\;L^1$) in August, while the lower abundances were found during the cold season. The minimun ciliate abundance was found in November when water temperature rapidly decreased. The temporal succession of dominant species was very clear and opportunistic. Pelagostrombidium sp., Tontonia simplicidens, Helicostomella subulata, and Myrionecta rubra were co-dominant in summer while Rimostrombidium orientale occurred abundantly in winter. Strombidium tressum and S. compressum, eurythermal species, were observed during all seasons. Based on the species-specific ecology of ciliate plankton, it is suggested that the indicative ciliate species can be applied as a biological tool to detect environmental change in the southern coastal waters of korea.

• Proceedings of the KSRS Conference
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• v.1
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• pp.441-444
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• 2006

The MERIS MCI (Maximum Chlorophyll Index), measuring the radiance peak at 709 nm in water-leaving radiance, indicates the presence of a high surface concentration of chlorophyll ${\underline{a}}$ against a scattering background. The index is high in 'red tide' conditions (intense, visible, surface, plankton blooms), and is also raised when aquatic vegetation is present. A bloom search based on MCI has resulted in detection of a variety of events in Canadian, Antarctic and other waters round the world, as well as detection of extensive areas of pelagic vegetation (Sargassum spp.), previously unreported in the scientific literature. Since June 1 2006, global MCI composite images, at a spatial resolution of 5 km, are being produced daily from all MERIS (daylight) passes of Reduced Resolution (RR) data. The global composites significantly increase the area now being searched for events, though the reduced spatial resolution may cause smaller events to be missed. This paper describes the composites and gives examples of plankton bloom events that they have detected. It also shows how the composites show the effect of the South Atlantic Anomaly, where cosmic rays affect the MERIS instrument.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.3
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• pp.160-180
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• 2012

We have studied the eukaryotic plankton species diversity to compare the community structure of fresh and brackish waters in the lower reaches of the Nakdong River using metagenomic methods. We constructed 18S rDNA clone libraries of total DNAs extracted from environmental water samples collected at Mulgeum (MG100929, fresh) and Eulsukdo bridge (ES, brackish). Through the steps of colony PCR, PCR-RFLP, sequencing and similarity analysis, we discovered the diverse species composition of eukaryotic plankton. Total 338 clones (170 at MG100929 and 168 at ES) were analyzed, and then we found 74 phylotypes (49 for MG100929 and 25 for ES). From the phylogenetic analysis, we confirmed various eukaryotic plankton of broad range of taxonomic groups, including Stramenopiles, Cryptophyta, Viridiplantae, Alveolata, Rhizaria, Metazoa, and Fungi. We also found several unreported species in Korea and candidates of new taxonomic entities at levels higher than genus. Especially, the cryptic species diversity including unreported phylotypes of Pirsonia (Stramenopiles) and Perkinsea (Alveolata) suggests that the molecular monitoring method can produce new informative biological data in monitoring the changes in the Nakdong River Mouth ecosystem.

• Korean Journal of Ecology and Environment
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• v.33 no.4 s.92
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• pp.358-365
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• 2000

To evaluate the influences of stocking and removal of silver carp on plankton communities and physicochemical parameters, fish biomanipulation was conducted in six enclosures constructed on the coast of a hypertrophic lake during the summer of 1997. Of these, three enclosures were established for the fish-stocking experiment; one fishless enclosure used as a control and two enclosures with high and low densities of fish. The other three enclosures for the fish-removal experiment were prepared in an entirely converse process compared to that for fish stocking. The results of randomized intervention analysis (${\alpha}=0.05$) showed significant changes in several physicochemical parameters and plankton communities after fish stocking and removal. Fish stocking decreased water transparency, DO, pH and chi-a (> $40\;{\mu}m$), while increasing the concentration of nitrogen and chi-a (<$2\;{\mu}m$). However, water transparency did not increase by fish removal. Small plankton communities, such as picocyanobacteria, eukaryotic picoplankton and ciliates (<$2\;{\mu}m$) showed significant reciprocal changes after both fish treatments: increase by the presence of fish and decrease by the absence of fish. No count of large sized phytoplankton and zooplankton showed significant change in the presence of fish, while large zooplankton, Diaphanosoma, Cyclopida and nauplii were significantly increased by fish removal. Although the frequent heavy-winds and endless supply of phosphorus from the lake sediment strongly disturbed the fish behavior and enclosure management, the stocking and removal of silver carp showed an obvious reciprocal influences on plankton communities and its physico-chemical parameters in a shallow-hypertrophic lake.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.4
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• pp.223-231
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• 2014

In order to prevent the spread of non-indigenous aquatic species through the ballast water in commercial ships, International Maritime Organization (IMO) adopted in 2004 the International Convention for Control and Management of Ship's Ballast Water and Sediments. The Convention mandates treatment of ballast water for most transoceanic voyages and its confirmation of treatment is made with plankton live/dead assay. Fluorescein diacetate assay (FDA), which produces bright green light for live phytoplankton, has been a de facto standard method to determine the survival of marine plankton, but its staining efficacy has been in dispute. In the present study, we examined the limitation of FDA, and compared its efficacy with Neutral red (NR) staining, another promising assay and widely used especially for zooplankton mortality. For all phytoplankton species studied in the present study, except Ditylum brightwellii, the staining efficiency was <50% with FDA. The green FDA fluorescence interfered with phytoplankton autofluorescence in most samples. In contrast, NR assay stained over 90% of both phytoplankton and zooplankton species tested in this study. FDA assay also showed that green FDA fluorescence rapidly faded when phytoplankton cells were exposed to microscope light. Both FDA and NR assay were negative on formalin-killed individuals of both phytoplankton and zooplankton species. Our results suggest that NR assay is more effective for determining the survival of marine plankton and can be applied to test the efficacy of ballast water treatment.

• Journal of applied mathematics & informatics
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• v.32 no.5_6
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• pp.555-566
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• 2014

In this paper, we formulate two chemostat type models of phytoplankton and zooplankton population dynamics with instant nutrient recycling to study the role of viral infection on phytoplankton. The infection is transmitted only among phytoplankton population and it makes them more vulnerable to predation by zooplankton. It is observe that the chemostat system is very stable in the absence of viral infection but the presence of viral infection make the chemostat system sensitive with respect to the grazing rate of infected-phytoplankton by zooplankton. Further, if the grazing rate is less than certain threshold the system remain stable and exhibits Hopf-bifurcation after crossing it.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.1
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• pp.51-60
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• 1990

Some species of dinoflagellates were considered as one of the causative organisms of PSP(Paralytic Shellfish Poison) or DSP(Diarrhetic Shellfish Poison). Fish and shellfish are intoxicated by feeding of toxic plankton, sometimes human is intoxicated by feeding on these intoxicated fish and shellfish. In past ten years, the physiological and ecological studies of the toxic plankton has been investigated for development of monitoring system and preventation and control measures of PSP. However, in our country still little is known on a research for the toxic dinoflagellates. This paper reviews the general biology, taxonomic problem, physioecology and culture method of the toxic planktons such as Protogony-aulax and Dinophysis.

• 한국해양학회지
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• v.7 no.2
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• pp.47-58
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• 1972

Densities and composition of phytoplankton and zooplankton, concentrations of particulate organic carbon, particulate organic nitrogen, and particulate inorganic matter were determined in the coastal area of Ko-ri during one year. There are peaks of densities of plankton organisms in summer, autumn, and spring Concentrations of particulate organic carbon ranged from 35 to 3,785 mg/㎥ (averaging 868mg/㎥ ), particulate organic nitrogen ranged from 4.4 to 158mg/㎥ (averaging 45mg/㎥), inorganic suspended matter ranged from 0.6 to 11.6 mg/L (averaging 5.7mg/L), and the carbon-nitrogen ratios of the suspended matter were varied from 0.5 to 231(averaging 35), with each seasonal cycle. The phytoplankton density and particulate organic carbon were possitively correlated from March to November, negatively from December to February, and the zooplankton dinsity and particulate organic nitrogen were well correlated.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.839-841
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• 2009

Dinoflagellates are known to cause red tide outbreaks and even to produce toxin. Recently, red tide events have frequently occurred in several embayments of the Korean coast and have brought serious damage to inshore fisheries. Thus, the red tide research activities including the taxonomy as well as distribution of toxic dinoflagellates have received ever increasing attention in Korean waters. Therefore, it is necessary to conduct an extensive taxonomical study on red tide organisms in coastal zone of Korea. The present study is to clarify the fine structures of Prorocentrum spp. and to describe each species with taxonomical notes for plankton monitoring network.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.842-844
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• 2009

The major group which contains all the organisms that are commonly termed Dinoflagellates is called the division Pyrrophyta or Dinophyta in botanical systems and the order Dinoflagellida or Dinoflagellata in zoological systems. Most dinoflagellates are biflagellated solitary planktonic cells. A taxonomic survey of the dinoflagellate family, Triadiniaceae Dodge was conducted for plankton monitoring network in the coastal waters of Korea. Identification of species in water samples was usually done by using differential interference contrast (DIC), which revealed especially well lighted thecal structures. For the apparent three-dimensional image, scanning electron microscope (SEM) was used. Two species were identified and described, which were Triadinium orientale(Lindemann)Dodge and Triadinium sphaericum(Murray and Whitting)Dodge.