• Journal of Environmental Science International
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• v.10 no.2
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• pp.159-166
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• 2001

We studied the appearance and proliferation of red tide organisms from March, 1998, to February, 1999, in the Jindong Bay. There were two red tide events during investigation, and we found that the dominant species Ceratium furca in May and Gymnodinium sanguineum in September, 1998. At surface, temperature and salinity showed 18.3~19.7$^{\circ}C$ and 30.6~30.9 psu in May and 25.6~27.$0^{\circ}C$, 28.0~28.5 psu in September, respectively. When the red tide occurred, the water mass stable. Dissolved inorganic nitrogen(DIN) and dissolved inorganic phosphate(DIP) in Jindong Bay showed seasonal variability. In May, the nitrogen was a limited nutrient in which the ratio of DIN versus DIP was less than 16 (Redfield ratio), while in September phosphate. During June to September, 1998, phosphate acted as a limited nutrient due to the increased river run-off from land. In May, chlorophyll-a, dissolved oxygen(DO) and chemical oxygen demand(COD) showed higher than 20$\mu\textrm{g}$/$\ell$, 10mg/$\ell$ and 5.0mg/$\ell$, respectively. In September, they showed in turns 100$\mu\textrm{g}$/$\ell$, 10mg/$\ell$ and 10mg/$\ell$, respectively.

• Korean Journal of Microbiology
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• v.29 no.6
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• pp.361-370
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• 1991

Physical and chemical environmental factors influencing on the outbreak of freshwater red tide by Peridinium bipes (dinoflagellate) in Soyang Reservoir were studied. Red tide occured in the site of inflowing of tributary streams annually, but the extent and severity of red tide varied from year to year. Several environmental factors such as water level, nutrient releasing from sediment, cyst resuspension, and concentrations of $Ca^{2+}$ and $Mg^{2+}$were studiedin relation to development, extent, and duration of red tide. In June of 1989 and 1991, the red tides of Peridinium bipes were very severe, and these red tides coincided with notable and rapid drawdown of lake water in late spring. Nutrient releasing and cyst resuspension by turbulence during drawdown were suggested as main causes of red tide. The quanity of nutrient releasing from sediment and hydrometeorological factors such as run-off and wind may determine the extent and duration of red tide.

• ALGAE
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• v.22 no.3
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• pp.241-246
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• 2007

Cochtodinium votykrikoides -related red tide is the most notorious tidal bloom, resulting in mass mortality to marineanimals. This study aimed to test the effect of C. polyknkoides on the lethality to Haliotis discus hannai under con-trolled conditions. The oxygen demand of C. polykrikoides increases to reach its peak duhng the night, while the oxy-gen usage by H. discus hannai was continuously decreased with a threshold of 2 mg L U. The addition of C.polykrikoides did not effect the respiration of the H. discus hannai. However, the usage of oxygen by C. polykrikoidesduhng the night may lead to anoxia in the animal. With aeration, the level of dissolved oxygen (D.O.) was between6.06 and 7.28 mg LU; 90% of abalones survived even with a high concentration of C. potykrikoides (9000 cells mL U).Without aeration (3 mg LU of D.O.), however, the H. discus hannai suffocated immediately. Once 20 hours hadelapsed, all of the abalones were dead. The density of the H. discus hannai population contributed to their mortality.Therefore, aeration during the night and maintaining lower abalone densities is the best way to promote the sur-vivorship of H. discus hannai during a C. polykrikoides red tide.

• Fisheries and Aquatic Sciences
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• v.6 no.2
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• pp.66-73
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• 2003

To understand the physiology of a suspension-feeding bivalve and its potential impacts on the dynamics of red tides on tidal flats, rates of clearance and ingestion of Glauconome chinensis were measured as a function of algal concentration, when the bivalve was fed on a nontoxic strain of red tide dinoflagellate Prorocentrum minimum, Cochlodinium polykrikoides or Scrippsiella trochoidea. With increasing algal concentration, weight-specific clearance rate increased rapidly at lower concentrations and after reaching the maximum at ca. 0.2 to 1.0 mgC/L, it decreased at higher concentrations. Maximum clearance rate was nearly equal for different algal species and ranged between 2.1 and 2.6 L/g/hr. Weight-specific ingestion rate also increased at lower algal concentrations but saturated at higher concentrations. Maximum ingestion rate was 2 to 10 fold different with different algal species: S. trochoidea (10.1 mgC/g/hr), P. minimum (3.9 mgC/g/hr), and C. polykrikoides (0.99 mgC/g/hr). Nitrogen and protein content showed that S. trochoidea is the best among the tested three red tide dinoflagellates. The maximum filtration capacity, calculated by combining the data on ingestion rate from laboratory experiments and those from the field for the density of the bivalve and the red tide dinoflagellates was 4.7, 1.4, and 25.3 tons/m2/day for P. minimum, C. polykrikoides, and S. trochoidea, respectively. It is hypothesized that the abundant suspension-feeding bivalves in tidal flats can effectively mitigate the outbreak of red tides.

• Journal of Environmental Impact Assessment
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• v.12 no.5
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• pp.341-348
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• 2003

Seasonal characteristics of water quality and effect of the freshwater discharge during open the tide embankment in Haechang Bay were evaluated. In the freshwater, where interior of the tide embankment, COD and Chl-a exceeded about 4mg/L and $10mg/m^3$, respectively, independent of season, while in the seawater they showed high values in April and July in contrast to the other period due to input of freshwater and increase of phytoplankton, respectively. The content of seawater inorganic nitrogen maintained a relatively high level at inner part of the bay, whereas high values of inorganic phosphorus content was distributed at all over the bay. The limiting factor for algal growth was nitrogen with respect to the N/P ratio. The compass of influence by the freshwater discharge in April was quite different with water pollutants. As a result of the salinity variation with time, the freshwater extended strongly to offshore from the surface layer without mixing with depth when open the tide embankment, and reached within about one hour at a station which is 3.5km from the tide embankment. To effective water quality management of Haechang Bay, discharge rate and pollutant loads should be controlled.

• Proceedings of the KSRS Conference
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• v.1
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• pp.324-327
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• 2006

This research is about the optical characteristic of red tide which is collected from Nam-Hae for basic research of red tide remote sensing technique development. 21 kinds of red tide organisms are cultivated to investigate optical characteristic of them on the level of laboratory, and chlorophyll specific absorption coefficient($a^*$) and backscattering coefficient($b_b^*$) are estimated by using spectrophotometer. Absorption spectrums according to species are appeared diversely from 0.005 to 0.06 (mg/ $m^2$), and the shapes of spectrums are also different. The range of $b_b^*$ are appeared $10^{-2}{\sim}10^{-4}$ mg/ $m^2$, which have around 100 times differences between species, and the shape of spectrum also have significant difference between species. These results are able to use as an input data of inverse model from ocean color.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.391-396
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• 2005

Red tide(harmful algae) in the Korean Coastal Waters has a given a great damage to the fishery every year. However, the aim of our study understands the influence of meteorological factors (air and water tempaerature, precipitation, sunshine, solar radiation, winds) relating to the mechanism of red tide occurrence and monitors red tide by satellite remote sensing, and analyzes the potential area for red tide occurrence by GIS. The meteorological factors have directly influenced on red tide formation. Thus, We want to predict and apply to red tide formation from statistical analyses on the relationships between red tide formation and meteorological factors. In future, it should be realized the near real time monitoring for red tide by the development of remote sensing technique and the construction of integrated model by the red tide information management system (the data base of red tide - meteorological informations).

• The Korean Journal of Ecology
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• v.9 no.3
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• pp.149-160
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• 1986

Relationship between the causative organi는 of red-tide and environmental factors had been ecologically dealt wtih. The surveys were conducted at seven station in Jinhae Bay from July to September 1981. The water temperature and salinity had wide range, i.e. 23.3~29.3$^{\circ}C$ and 19G.78~31.29$\textperthousand$, but several chemical factors remarkably fluctuated; dissolved oxygen 102.9~210.4%, COD 2.10~8.96mg$O_2$/l, pH 8.1~9.4, $NO_3$-N trace~1, 052$\mu$g/l, $PO_4$-P 0.6~58.9$\mu$g/l and chlorophyll-a 2.18~290.5mg/$m^3$ in the observed area. The red-tide was mainly caused by two dinoflagellata taxa throughout major outbreaks occurred in July through September. Leading species of red-tide were Gymnodinium nagasakiense belong to the ajor species. During the surveyed period, cell nubers of the causative organisms of the red-tide extensively varied from 3${\times} /10^4$ cells/l to $1.5\times10^7 $cells/l with moths and stations; Prorocentrum spp. 0.3~12.5$\times\10^5$ cells/l in July; Gymnodinium nagasakiense 0.2~5.9$\times10^6 cells/l, 1.1~4.7$\times10^6$ cells/l, and 0.2~15.1$\times10^6$ cells/l in July, August, and September, respectively. Gymnodinium nagasakiense red-tide seemed to be caused by the high water temperature in summer, unusually low salinity due to heavy rains, and the concentrated nutrients for phytoplankton supplied with the municipal sewages from the urban areas and the wastewaters from the industrial complexes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.2
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• pp.165-173
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• 1996

Large amounts (300 grams) of natural red tide plankton, Cochlodinium polykrikoides, was collected at the Yokji island coastal waters, Kyeongnam, Korea, on October, 1993. Using the bioassay systems, bioactive materials were screened from methanol extracts of C. polykrikoides. Live C. polykrykoides was toxic to fishes, however, the water soluble and chloroform soluble fraction of their methanol extracts did not shown ichthyotoxicity (5 mg/ml), and toxicity to mice (50 mg, i.p,). These fractions did not show any peaks corresponding to paralytic shellfish toxins or diarryhetic shellfish toxins on the fluorometric HPIC chromatograms. Neither fractions did not show antibiotic activities by paper disk (10 mg/disc) test and chloroform soluble fraction showed only $20\%$ growth inhibition activity on the Lymphoid P-388 at the concentration of $180\;{\mu}g/ml$. Hemolytic activity was detected by both fractions. Fatty acid analysis by GC, GC/MS and proton NMR showed that the chloroform soluble fraction composed of $25.3\%$ of DHA (dorosahexaenoic acid) and $15.3\%$ of IPA (eicosapentaenoic acid) as the hemolytic components.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.3
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• pp.270-276
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• 2014

Seasonal characteristics of water and sediment qualities and potential effects of the freshwater discharge from a small tide embankment interior in a coastal area in Goheung county were investigated from May to September in 2012. Chemical oxygen demand values (COD) were mostly higher than 2 mg/L in summer ebb tide, which exceed the standard value of water quality criteria II of acceptable level for aquaculture activities. Nitrogen and phosphorus were found as the limiting nutrients for algae growth in summer and fall and in spring, respectively. Nitrogen was the limiting nutrient for diatom growth in the whole studied period. The sudden high values of COD, ammonia, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) were found in water sample collected from station 5 which located in front of the tide embankment sluice gate during spring ebb tide. The freshwater discharge form the tide embankment interior maybe affected the survey areas during a short time interval. Mean values of eutrophication index of the surveyed coastal region in spring, summer and fall were all bigger than 1. Water quality was mostly considered at level II which acceptable for aquaculture activities. Sediment quality in this study was generally in the range of standard for fisheries environment.