• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.370-379
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• 2007

Short-term variations of phytoplankton community structure in the southeast coastal waters of Korea from July to September in 2006 were investigated with data set of phytoplankton, chemical and physical water properties, and meterological data. A total of 11 sampling sites of 4 different depths (surface, 5 m, 10 m, and bottom) were visited on July 11-14, July 24-26, August 7-10, August 21-24 and September 5-8. We identified 151 species in 63 genera of phytoplankton in which diatoms were the most diverse group composed of 92 species in 37 genera. Dinoflagellates were the second diverse group of 52 species in 22 genera. The other groups include 7 species in 4 genera including Raphidophytes, and Euglenophyta. After rainy season, excessive nutrients from adjacent streams to the stratified water column proliferates Chaetoceros group in July. But biomass of phytoplankton and nutrient concentrations were decreased during the period of a drought in August. However, Chaetoceros was the most dominant genera in all depths of the first, second, third and fifth cruises, except the 4th cruise on August 21-24 when dominant group were dinoflagellates including Gymnodinium spp. and Cochlodinium polykrikoides. The characteristic of phytoplankton community and environment condition during summer 2006 can be summarized as: 1) low concentration of nutrients caused by a long lasting drought in August 2) no summer outbreak of C. polykrikoides because the strength of offshore waters was weak than other years, and 3) Chaetoceros spp. was the dominant species despite short period appearance of dinoflagellates.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.05a
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• pp.85-87
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• 2003

문헌 32편에서 조사된 출현종수는 43종에서 200종까지였고, 그 중에서 주요종수는 2종에서 27종까지로 조사되었다. 본 조사에서 기록한 주요종은 모두 50속 116종이었고, 규조류 34속 89종(76.6%), 와편모조류 11속 22종(18.9%), 황갈색조류 2속 2종(1.7%), 남조류, 라피도조류, 유글레나조류가 각각 1속 1종(0.9%)이었다. 생태적 특성을 반영하는 주요종으로서는 우점종이 Actinoptychus serunius를 비롯하여 79종, 출현빈번종이 Coscinodiscus centralis를 비롯하여 50종, 적조원인종이 Cochlodinium polykrikoides를 비롯한 36종이었다. 또한 3가지의 주요 특성을 모두 지닌 종은 Prorocentrum micans를 비롯한 11종이었다. 여러 문헌에서 주요종으로 언급했던 종은 규조류인 Skeletonema costatum이었고 단일 속(genus)으로서 18종의 많은 종이 조사된 속은 Chaetoceros속이었다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.95-100
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• 2012

This study was determined to analysis marine environmental and phytoplankton monitoring in Wando coastal waters in August during the period of 2009-2010 and provided the basic environmental data against Southwest Sea of Korea. In August, 2009, the distribution of water temperature and salinity showed an unique characteristics for all of stations, which was associated with a long duration of rainfall after July, 2009 and a lack of sunshine. In the lower of August, 2010, the stratification of water temperature and salinity was shown, which was caused by an intensive sunshine after the middle of August, 2010. Gangjin Bay and Gogeundo waters showed a highly different water temperature and transparency. It is thought that two regions have a distinct water mass and characteristics. In dissolved oxygen and oxygen saturation were higher according to higher water depth regardless of stations. In August, 2009, different dominant species occurred that Gangjin Bay showed a higher cell density of diatom, but Gonyaulax polygramma played an important role in dominant species in Gogeundo waters. It is associated with the introduction red tide water of G. polygramma occurring to southern coastal water in August, 2009. In August, 2010, diatom was extremely higher cell density compared with that of dinoflagellate that regarded as adaptive microrganism against higher quantity of suspended solid in Wando waters. Although Wando has a record of Cochlodinium red tide, this species may be difficult to grow and persist. Dominant species, diatom, play an important role in food organism for shellfish and forming a ecological lineage.

• Korean Journal of Environmental Biology
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• v.32 no.3
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• pp.159-167
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• 2014

In this study, I examined the water quality and phytoplankton community in aquaculture laver farm in the southwest part of Aphae-do, South Korea, based on the young leaf stage, middle leaf stage, and adult leaf stage of laver thallus from October, 2013 to January, 2014. It was observed that the Aphae laver farm, as located in shallow waters, was found to have a serious resuspsension of the surface sediments due to physical disturbance caused by winds and tidal mixing. Such a resuspension of surface sediments coupled with nutrients supply obstructs light penetration into the sea for its huge amount of total suspended matters. As a result for this reason, it was viewed toimpedthe growth of phytoplankton was impeded as it also competes with laver to absorb the same kinds of nutrients as laver does during the laver growth period in winter. Such elements of the marine environment in Aphae laver farm are in contrast with the environment of Japan, where nutrients including dissolved inorganic nitrogen, in particular, are insufficient to cause the recent laver bad harvest, discoloration and quality degradation while large diatoms, with their higher nutrients absorption efficiency than laver, generate winter red tide. In other words, an important factor to maintain the high laver production in the southern parts of West Sea of Korea was found to be the marine environment of its laver farms where large diatoms are prevented from growing due to nutrients supply and dense seston weights from resuspended matters by physical disturbances.

• Korean Journal of Environmental Agriculture
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• v.26 no.2
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• pp.159-170
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• 2007

This study was focused on the investigation of the phytoplankton flora and community structure for changing of water environment at the rivers in the lower part of Nakdong river, The samples for this study were collected every month from Jan. 2004 To Dec. 2004. the 196 species belonged to 94 genera were identified during this study periods. The number of species was recorded the maximum 124 taxa in summer and the minimum 69 taxa in winter, We observed the maximum taxa (92 taxa) at the site No. 20 and the minimum taxa (55 taxa) at the site No. 8, respectively. Among the phytoplankton communities, diatoms were dominated over 40% of total phytoplankton groups. Subdominant groups were green algae (over 20% of total phytplankton groups). During this study periods, the 60 species were investigated ecologically significant species (46 cosmopolitic species, 25 pollution indicator, 21 redtide causative species, 8 dominant species, and 7 frequently occurred species). According to the cluster analysis by similarity index, the study sites could be divided into 4 groups.

• Journal of Wetlands Research
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• v.9 no.2
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• pp.71-84
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• 2007

Masan Bay is a representative semi-closed bay acted as a sedimentation reservoir with a slow current velocity and a poor water circulation in Korea. The pollutants from terrestrial sources into the Masan Bay have apparently environmental pollution problems, such as eutrophication, red tied, and hypoxia. In this study, An ecological modeling work was performed to estimate the material circulation including the growth of bivalve in ecosystem. Furthermore, the effect of water purification was calculated by filter feeding bivalve to particulate organic matter just like COD and phytoplankton. And Water quality management strategy by bio-purification of bivalve is derived through selection of location, quantification of bivalve aquaculture farm. The results showed that the optimum location for bivalve farming is where phytoplankton accumulation by physical processes is maximized and the optimum density and area of bivalve are 35 individuals $m^{-3}$ and ca. 500 hectare, respectively. When assuming conditions for the optimum growth of bivalve, COD could decrease by up to 18% even without other reduction of pollution loads.

• Journal of Aquaculture
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• v.8 no.1
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• pp.47-58
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• 1995

Field studies on the seasonal succesion of phytoplankton population were carried out at the 25 stations of the breeding ground in Kogum-sudo, Southern coast of Korean peninsula in Feburuary, April, August and October, 1993. Sixty four species belonging to 40 genera were identified. Predominant species were mainly centric diatoms throughout the four seasons, two centric diatoms, Skeletonema costatum and Thalassiosira sp. and a pennate diatom, Thaiassionema nitzschioides in the winter; two pennate diatoms, Thaiassionema nitzschioides and Asterionella kariana, and especially a dinoflagellate, Heterocapsa triquetra (station 10) in the spring, two centric diatoms, S. costatum and Chaetoceros diadema in the summer; and a centric diatom, Rhizosolenia alata and a pennate diatom, Bacillaria paxillifer in the fall. The main red tide organisms in the breeding ground were dinoflagellates, Prorocentrum dentatum, P. minimum, P. triestinum, Ceratium furro, Gymnodinium sanguineum, Noctiluca scintillans, H. triquetra, Scrippsiella trichoidea and a diatom S. costatum in the Kogum Sudo. Seasonal phytoplankton cell numbers were in a wide range between $8.8\times10^3$ cells/l and 1.4\times10^6$ cells/l; The seasonal average cell numbers were $12.2\times10^4\pm5.9\times10^4$ cells/l $(mean\;\pm\;standard\; diviation)$ in the winter, $3.3\times10^4\pm1.4\times10^4$ cells/l in the spring, $48.4X10^4\pm40.0\pm10^4$ cells/l in the summer, and $3.6\times10^4\pm1.9\times10^4$ cells/l in the fall, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.372-381
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• 2014

We investigated cause of non-outbreak of Cochlodinium polykrikoides blooms in the western coast of Jaran Bay during Summer, 2013, by combining chemical field data and physiological data of C. polykrikoides, which had been already published. The predominant species were mainly diatoms, and dominant species was Cerataulina pelagica, Chaetoceros spp., Navicula spp. and Nitzschia spp.. In case of dissolved inorganic nutrients in the western coast of Jaran Bay, dissolved inorganic phosphorus (DIP) was similar to that in previous outbreak period of C. polykrikoides blooms, but dissolved inorganic nitrogen (DIN) was lower. C. polykrikoides might be disadvantageous in competition with diatom species because half-saturation constants (Ks) of C. polykrikoides for inorganic nutrients was lower than those of diatoms. Also, the western coast of Jaran Bay, where DIN concentration is relatively low, was an unfavorable environment for growth of C. polykrikoides characterized by nitrogen dependence. Therefore, C. polykrikoides which have the disadvantageous position for competition of inorganic nutrient might have been suppressed by diatom blooms under environment of low nutrient in the western coast of Jaran Bay.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.4
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• pp.173-178
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• 2004

Chronic Cochlodinium blooms in the southern waters of Korea have brought about considerable economic losses for about a decade, This paper aims to reframe current perspectives on the outbreak mechanism and the remediation schemes through a thought experiment in a context of mass balance and mathematical ecology. Far different explanations emerge from a careful examination of the scientifically unnoticed clues and a through discussion on the phytoplankton conservation equation. Logic of the eutrophication-induced red tide subjects to criticism. It is strongly recommended that the current remediation scheme to exterminate the target species should be rerouted to an environmentally sound competition enhancement tactics. Finally a novel convergence-float-aggregation hypothesis is proposed as an outbreak mechanism.

• Journal of Environmental Science International
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• v.15 no.10
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• pp.961-966
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• 2006

An algal assay procedure using an indigenous phytoplankton assemblage was tested to estimate the propagation of red tide phytoplankton species and determine the optimal time interval at which to measure growth yield in eutrophic marine waters where red tides frequently occur. Various red tide phytoplankton species were propagated on a large scale by adding nitrogen or phosphorous. This procedure was useful for estimating the limiting nutrient, elucidating the mechanisms underlying red tides, and determining the levels of increases in organic matter in eutrophic coastal waters. The algal assay using indigenous C. polykrikoides showed that this species did not always propagate, apparently because of very low concentrations of trigger elements that are necessary for its growth, rather than as a result of other environmental characteristics, e.g., water temperature or stress from sampling. In the winter, when water temperatures are lower than in spring, summer, or autumn, maximum propagation and the limiting nutrient could be estimated by measuring phytoplankton biomass at 2 - 3-day intervals. However, in the other seasons, when water temperatures are higher, phytoplankton biomass should be measured at 2-day intervals. In particular, daily monitoring will be required to determine precise growth yields in warm seasons.