• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.1
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• pp.41-48
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• 2012

Red tide is a natural phenomenon temporary blooming harmful algal with changing sea color from normal to red, which fish and shellfish die en masse. It also give a bad influence to coastal environment and sea ecosystem. The damage of sea farming by a red tide has been occurred each year which it cost much to prevent disasters of red tide blooms. Red tide damage and prevention cost of red tide disasters can be minimized by means of prediction of red tide blooms. In this paper, we proposed the red tide blooms prediction method using ensemble train. The proposed method use the bagging and boosting ensemble train methods for enhancing red tide prediction and forecast. The experimental results demonstrate that the proposed method achieves a better red tide prediction performance than other single classifiers.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.533-541
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• 2011

Algal blooms have caused problems for drinking water as well as eutrophication. However it is difficult to control algal blooms by current warning manual in rainy season because the algal blooms happen in a few days. The water quality data, which have high correlations with Chlorophyll-a on Daecheongho station, were analyzed and chosen as input data of Artificial Neural Networks (ANN) for training pattern changes. ANN was applied to early forecasting of algal blooms, and ANN was assessed by forecasting errors. Water temperature, pH and Dissolved oxygen were important factors in the cross correlation analysis. Some water quality items like Total phosphorus and Total nitrogen showed similar pattern to the Chlorophyll-a changes with time lag. ANN model (No. 3), which was calibrated by water temperature, pH and DO data, showed lowest error. The combination of 1 day, 3 days, 7 days forecasting makes outputs more stable. When automatic monitoring data were used for algal bloom forecasting in Daecheong reservoir, ANN model must be trained by just input data which have high correlation with Chlorophyll-a concentration. Modular type model, which is combined with the output of each model, can be effectively used for stable forecasting.

• Fisheries and Aquatic Sciences
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• v.5 no.1
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• pp.75-78
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• 2002

The effects of Coehlodinium polykrikoides on the gill of red sea bream, Pagrus major, were examined to clarify the ichthyotoxic mechanisms of this plankton species. The gill of fish exposed to dense blooms over 3,000 cells/mL for 24 h showed severe epithelial separation: a severe edema was found in the secondary lamellar epithelium and interlamellar regions of primary filament. In addition, lipid peroxidation of gill tissue in Coehlodinium-exposed fish was about 2.5 times higher than that of control. The composition of glycoproteins in the gill mucus of Coehlodinium-exposed fish was also changed. These results suggest that the loss of structural integrity of cell membranes in fish gill may be deeply involved in fish death by C. polykrikoides.

• ALGAE
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• v.18 no.4
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• pp.361-363
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• 2003

This study was conducted at Seomjin River estuary to identify the causative species of algal bloom and their blooming cycles. Field surveys were conducted at 4 stations in every week from April to December of 1999. Thirty species were observed as the causative species of alga bloom. Skeletonema costatum, Thalassiosira sp., and microflagellate spp. (mixed red tide: Chroomonas sp. and two species of Prasinophycea) made algal blooms during the present study period. In addition, toxic algal species of diatom Pseudo-nitzschia multiseries and dinoflagellate Dinophysis acuminata were observed. The algal blooms were caused by microflagellate spp. in June, Thalassiosira sp. in July and Skeletonema costatum in August. Generally, the algal blooms persisted for about 5 days in this area.

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.212-218
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• 2006

Three out of fourteen Microcystis-dominant cyanobacterial blooms in Central India were found to be toxic to mice ($LD_{50}$ ranging from 35-450 mg bloom dry mass/kg body weight). The liver architecture of the treated mice showed characteristic symptoms of hepatotoxicity relative to the untreated controls, with increased enzyme activities of serum lactate dehydrogenase (LDH), serum glutamate oxaloacetate transaminase (SGOT), alkaline phosphatase (ALP), and serum glutamate pyruvate transaminase (SGPT). RP-HPLC revealed the presence of microcystin-LR, microcystin-RR, and desmethyl microcystin-RR in the given region to maximum amounts of 390, 1,030, and $860{\mu}g/g$ bloom dry weight, respectively, corresponding to a maximum of 2.8 mg/l microcystin-LR in the lake water. Further confirmation of the microcystin variants was conducted using a MALDI-TOF MS analysis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.109-113
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• 1998

The clay and yellow loess have capability to adsorb and precipitate particles. The removal efficiencyes of those flocculents on the dinoflagellate, Cochlodinium polykrikoides, have been studied in laboratory and in field near Tongyong fish farm in September, 1996. The removal efficiencyes in the laboratory experiment was $43\%$ for $2\;g/{\ell}$, $64\%$ for $6g/{\ell}$ and $88\%$ for $10\;g/{\ell}$ in one hour after dispersion. No big difference of removal efficiency was found between the raw and the acid-activated loess. In the field survey, the removal rates ranged from 72 to $80\%$ in 30 min after the dispersion. The effect of loess scattering on water quality was estimated. The concentrations of dissolved inorganic nitrogen (DIN), chemical of gen demand (COD) and chlorophyll a decreased more or less after dispersion, while the concentration of suspended solid (SS) increased. The concentrations of dissolved oxygen (DO) and dissolved inorganic phosphorous (DIP) were kept constant. These results indicated that the dispersion concentration of more than $10g/{\ell}$ has a good removal efficiency of above $80\%$ without big variation of water quality after dispersion of yellow loess.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.581-590
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• 2007

A float-type weir has been proposed for the control of algal blooms in some of eutrophic reservoirs recently. It is known as a costly and ecologically sound method, but there is little understanding about the sustainability of this low-cost technology for reservoirs that are located in monsoon climate areas where large flood events during the summer cause high water surface fluctuations. The objective of this study was to assess the effectiveness of a skimmer weir aimed at controlling algal blooms in the lacustrine zone and near the drinking water withdrawal structures of Daecheong Reservoir under various hydrodynamic flow conditions. The effect of weir on the control of algal blooms was simulated using a laterally averaged two-dimensional hydrodynamic and eutrophication model that can accommodate vertical displacement of the weir following the water surface fluctuations. Numerical simulations were performed for two different hydrological conditions, 2001 and 2004 for representing drought year and normal year, respectively. The results showed that the weir is very effective method to control algal blooms in the reservoir by curtailing the transport of phosphorus and algae from contaminated inflow to the downstream lacustrine epilimnion during the draught year. However, large flood events occurred in 2004 transported nutrients and algae built upstream of the weir into the downstream euphotic zone by strong entrainments.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.651-659
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• 2003

A new method was proposed to control Harmful Algal Blooms (HABs) by a biosurfactant sophorolipid. The effect of sophorolipid on the growth, motility, precipitation, and recovery of algal cells was investigated for four common HAB species, Scripsiella trochoidea, Prorocentrum minimum, Cochlodinium polykrikoides, and Heterosigma akashiwo. The motility and growth of algal cells were inhibited significantly at the concentration of 20 and 5 mg/l sophorolipid, respectively, and no recovery was observed under the above concentrations. The concentration of 20 mg/l sophorolipid was considered to be an effective concentration for the mitigation of HABs. A sedimentation test suggested that the maximum precipitation occurred at the end of 1 h, and the algicidal effect of sophorolipid was observed by a microscope. Comparative study showed that sophorolipid had marked algicidal capability. Analysis on biodegradability, toxicity, and cost effectiveness further demonstrated the potential of sophorolipid in future HABs mitigation.

• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.95-100
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• 2006

Measurements of ocean color from space since 1970s provided vital information with reference to physical and biogeochemical properties of the oceanic waters. The utility of these data has been explored in order to map and monitor highly toxic/or harmful algal blooms (HABs) that affected most of coastal waters throughout the world due to accelerated eutrophication from human activities and certain oceanic processes. However, the global atmospheric correction and bio-optical algorithms developed for oceanic waters were found to yield false information about the HABs in coastal waters. The present study aimed to evaluate the potential use of red tide index (RI) method, which has been developed by Ahn and Shanmugam (2005), for mapping of HABs in Korean and neighboring waters. Here we employed the SSMM to remove the atmospheric effect in the SeaWiFS image data and the achieved indices by RI method were found more appropriate in correctly identifying potential areas of the encountered HABs in Korean South Sea (KSS) and Chinese coastal waters during 1999-2004. But the existence of high absorbing and scattering materials greatly interfered with the standard OC4 algorithm which falsely identified red tides in these waters. In comparison with other methods, the RI approach for the early detection of HABs can provide state managers with accurate identification of the extent and location of these blooms as a management tool.

• 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.