• Fisheries and Aquatic Sciences
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• 제1권2호
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• pp.159-167
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• 1998

The environmental characteristics in shellfish farms were investigated in the western part of Jinhae Bay, 1996. During summer, anoxia and high nutrient concentrations were found in the bottom waters of shellfish farms. The concentrations of particulate organic species in seawaters were enriched, showing an average 57.44 uM for POC, an average 5.45 uM for PON, and an average 0.42uM for PP. The sediments environment in the farms was very polluted. The concentrations of COD and AVS were more than 20 mg/g.dry and 0.5 mg/g.dry, respectively. The total sedimentation rate was high as an average $7.81g/m^2/day$ with organic matter contents of $26\%$. Oxygen consumption rate was similar to polluted area as an average of $439mg/m^2/day$. Nutrient release rates were an average of $8.25mg/m^2/day$ for nitrogen and an average of $1.38mg/m^2/day$ for phosphorous. The cluster analysis through environmental data in summer indicated that DO, nutrient in the bottom water, and AVS in the sediment were important factors to characterize the polluted environmental site.

• Journal of Microbiology and Biotechnology
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• 제16권2호
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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.

• 한국수자원학회논문집
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• 제53권5호
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• pp.369-381
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• 2020

본 연구에서는 영산강의 송촌보와 죽산보의 녹조현상에 영향을 미치는 주요 인자들을 분석하고 3차원 수리동역학 EFDC 모델을 이용하여 유역의 점오염원 및 비점오염원의 영향을 분석하여 수질 개선을 위한 관리 우선순위를 선정하고자 하였다. 8개의 주요 지류와 2개의 하수처리장의 2018-2019년의 2년 간 수질 변화특성 분석하였으며 간헐적으로 다량의 비점오염물질이 유입되는 것으로 추정되는 영산강 유역 농경지의 배수문 등 비점오염원은 실측자료의 부족으로 정확한 분석이 어려웠다. EFDC 모델은 수위 및 수질에 대하여 각 6개 지점에 대해서 2018-2019년의 2년간 자료에 대하여 보정하였으며 각 오염원을 중심으로 시나리오를 분석하였다. 광주 제 1 하수처리장의 방류수는 현재의 수질을 75%까지 개선하여도, 승촌보 및 죽산보의 녹조현상이 개선되지 않는 것으로 나타났으며 이는 방류수 수질이 개선되어도 영산강 유역 조류가 성장하기에 충분한 영양염류가 존재한다는 것을 의미한다. 시나리오 분석을 통해 승촌보의 수질에는 황룡강이 가장 큰 영향을 미치며 죽산보의 수질에는 지석천의 영향이 가장 크고 이어서 황룡강의 영향이 큰 것으로 분석되었다. 따라서 승촌보의 수질 개선을 위해서는 황룡강의 수질 개선이 가장 중요한 것으로 분석되며 죽산보는 수질에 가장 큰 영향을 미치는 지석천의 수질 개선이 중요한 것으로 판단된다. 기타 소규모 비점오염부하 유입원에 대하여는 실측자료의 부재로 적절한 분석이 어려웠으며 향후 연구에 보완되어야 할 것으로 판단된다.

• 생태와환경
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• 제46권1호
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• pp.1-9
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• 2013

Algal blooms in potable water supplies are becoming an increasingly prevalent and serious water quality problem around the world. In addition to precipitating taste and odor problems, blooms damage the environment, and some classes like cyanobacteria (blue-green algae) release toxins that can threaten human health, even causing death. There is a recognized need in the water industry for models that can accurately forecast in real-time algal bloom events for planning and mitigation purposes. In this study, using data for an interconnected system of rivers and reservoirs operated by a New Jersey water utility, various ANN models, including both discrete prediction and classification models, were developed and tested for forecasting counts of three different algal classes for one-week and two-weeks ahead periods. Predictor model inputs included physical, meteorological, chemical, and biological variables, and two different temporal schemes for processing inputs relative to the prediction event were used. Despite relatively limited historical data, the discrete prediction ANN models generally performed well during validation, achieving relatively high correlation coefficients, and often predicting the formation and dissipation of high algae count periods. The ANN classification models also performed well, with average classification percentages averaging 94 percent accuracy. Despite relatively limited data events, this study demonstrates that with adequate data collection, both in terms of the number of historical events and availability of important predictor variables, ANNs can provide accurate real-time forecasts of algal population counts, as well as foster increased understanding of important cause and effect relationships, which can be used to both improve monitoring programs and forecasting efforts.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.168-168
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• 2023

The frequent occurrence of cyanobacterial harmful algal blooms (CHABs) in inland waters under climate change seriously damages the ecosystem and human health and is becoming a big problem in South Korea. Satellite remote sensing is suggested for effective monitoring CHABs at a larger scale of water bodies since the traditional method based on sparse in-situ networks is limited in space. However, utilizing a standalone variable of satellite reflectances in common CHABs dual-models, which relies on both chlorophyll-a (Chl-a) and phycocyanin or cyanobacteria cells (Cyano-cell), is not fully beneficial because their seasonal variation is highly impacted by surrounding meteorological and bio-environmental factors. Along with the development of Artificial Intelligence (AI), monitoring CHABs from space with analyzing the effects of environmental factors is accessible. This study aimed to investigate the potential application of AI in the dual-model strategy (Chl-a and Cyano-cell are output parameters) for monitoring seasonal dynamics of CHABs from satellites over Korean inland waters. The Sentinel-3 satellite was selected in this study due to the variety of spectral bands and its unique band (620 nm), which is sensitive to cyanobacteria. Via the AI-based feature selection, we analyzed the relationships between two output parameters and major parameters (satellite water-leaving reflectances at different spectral bands), together with auxiliary (meteorological and bio-environmental) parameters, to select the most important ones. Several AI models were then employed for modelling Chl-a and Cyano-cell concentration from those selected important parameters. Performance evaluation of the AI models and their comparison to traditional semi-analytical models were conducted to demonstrate whether AI models (using water-leaving reflectances and environmental variables) outperform traditional models (using water-leaving reflectances only) and which AI models are superior for monitoring CHABs from Sentinel-3 satellite over a Korean inland water body.

• 한국세라믹학회지
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• 제53권1호
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• pp.1-6
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• 2016

In this year, Koreans have a shortage in agricultural and drinking water due to severe algal blooms generated in major lakes. Waste oyster shells were obtained from temporary storage near the workplace at which oysters were separated from their shells. Heating ($1000^{\circ}C$ for 1 h in air) was employed to convert raw oyster shell powders into calcium oxide powders that reacted efficiently with phosphorus and nitrogen to remove algal blooms from eutrophicated wastewater. As the dispersed amount of heated oyster shell powders was increased, water clarity and visual light penetration were improved. Coagulation, precipitation and carbonation process of the heated oyster shell powders in a water purifier facilitated removal of eutrophication nutrient such as phosphorus and nitrogen, which is both beneficial and economically viable. $CO_2$ implantation by carbonation treatment not only produced thermodynamically stable CaO in oyster shells to derive precipitated calcium carbonate (PCC) but also accelerated algal removal by activation of coagulation and precipitation process. The use of oyster shell powders led to a mean reduction of 97% in total phosphate (T-P), a mean reduction of 91% in total nitrogen (T-N) and a maximum reduction of 51% in chemical oxygen demand (COD), compared with the total pollutant load of raw algal solution. Remarkable water quality improvement of algal removal by heated oyster shell powders and PCC carbonation treatment will allow utilization as water resources to agricultural or industrial use.

• 한국수자원학회논문집
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• 제49권9호
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• pp.789-798
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• 2016

최근의 우리나라 수계에서의 하천에서의 조류 대번성은 심각한 사회 환경적 문제가 되고 있다. 이중 독성이 강한 남조류의 발현은 수생태계의 건강성과 안전한 물공급에 위협이 될 수 있다. 영산강 수계의 승촌보와 죽산보 지점의 남조류 세포수와 환경인자간의 인과관계 분석을 위해 선백색화 시계열간의 배타적 상관분석을 수행하였고 이를 기반으로 이들 사이의 입출력 모형을 도출하였다. 입출력 모형의 겨울철 남조류 세포수 반응 특성을 고려하기 위해서 수온의 문턱거동을 도입하였고, 모형의 남조류 세포수에 대한 설명력을 증가시키는 효과를 얻었다. 입출력 모형의 남조류 세포수의 모의능이 완전하진 않으나, 비교적 간단한 구조를 가진 입출력 모형의 구조는 모형 적용의 용이성이 높은 것으로 판단된다.

• 에너지공학
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• 제26권1호
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• pp.68-75
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• 2017

Global warming affects water supply and water resources throughout the world. In many countries, climate change affects significantly on the fresh water resources. Vietnam is exposed mainly, to landslides and floods triggered by tropical storms and monsoon rains, although storm surge, whirlwind, river bank and coastal line erosion, hail rain. In addition to the prevalent drought, there are many major water challenges, including water availability, stress, scarcity and accessibility, because of poor resource management. Fast growth of urbanization, industrialization and population growth, agricultural activities and climate change cause heavy pressure on water quality. Both domestic and industrial wastewater, as well as storm water shares the same drainage. The common facilities for wastewater treatment are not available. Therefore, wastewater is treated only superficially and then discharged directly into rivers and lakes causing serious pollution of surface water environment. In this paper, we reported the severe water crisis and massive green algal blooms formation in Vietnam rivers and lakes. This is the biggest evidence of climate change variations in Vietnam.

• ALGAE
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• 제26권2호
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• pp.181-192
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• 2011

Ballasting and deballasting of shipping vessels in foreign ports have been reported worldwide as a vector of introduction of non-native aquatic plants and animals. Recently, attention has turned to ballast water as a factor in the global increase of harmful algal blooms (HABs). Many species of microalgae, including harmful dinoflagellate species, can remain viable for months in dormant benthic stages (cysts) in ballast sediments. Over a period of four years, we surveyed ballast water and sediment of ships docked in two ports of Tampa Bay, Florida, USA. Sampling conditions encountered while sampling ballast water and sediments were vastly different between vessels. Since no single sample collection protocol could be applied, existing methods for sampling ballast were modified and new methods created to reduce time and labor necessary for the collection of high-quality, qualitative samples. Five methods were refined or developed, including one that allowed for a directed intake of water and sediments. From 63 samples, 1,633 dinoflagellate cysts and cyst-like cells were recovered. A native, cyst-forming, harmful dinoflagellate, Alexandrium balechii (Steidinger) F. J. R. Taylor, was collected, isolated, and cultured from the same vessel six months apart, indicating that ships exchanging ballast water in Tampa Bay have the potential to transport HAB species to other ports with similar ecologies, exposing them to non-native, potentially toxic blooms.

• 해양환경안전학회지
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• 제26권5호
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• pp.523-530
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• 2020

국립수산과학원과 지역자치단체의 적조모니터링 결과를 바탕으로 해양환경 변동이 적조발생에 미치는 영향을 규명하였다. 1972년 적조 모니터링이 시작된 이후, 1980년대에서 1990년대까지 적조 발생은 지속적으로 증가를 하였으며, 1998년 109건의 최다 적조발생 이후 2010년대까지 감소 추세를 보이고 있다. 1970년대는 대부분 규조 적조가 발생하였으며, 1980년대에는 연안성 와편모조류가 주로 적조를 일으켰으며, 1993년 이후 Cochlodinium polykrikoides 적조가 지속적으로 발생하고 있다. 우리나라에서 수산피해를 일으킨 유해 적조생물은 3종이다. 1981년 진해만에서 Karenia mikimotoi에 의한 고밀도 적조가 발생하여 패류가 대량 폐사하였다. 1992년 통영해역에서 Karenina sp.에 의한 적조가 발생하여 양식어류를 폐사시켰으며, 1995년 C. polykrikoides 적조로 765억 원의 최대 규모의 수산피해가 발생한 이후 지속적으로 발생하고 있다. 연안해역의 영양염 농도는 1980년대에 가장 높았으며, 1990년 중반 이후 매우 감소하고 있다. 이러한 영양염 감소는 적조발생 감소를 잘 설명해 준다. 2016년 이후 30℃이상의 여름 고수온이 나타나며 C. polykrikoides의 적조 발생 범위와 규모는 매우 감소하였다. 2016년 K. mikimotoi 적조가 전남 장흥~고흥 해역에 발생하였으며, C. polykrikoides 적조는 여수해역에만 발생하였다. 2017년은 C. polykrikoides 적조 발생이 없었으며, Alexandrium affine 적조가 전남 여수~경남 통영해역까지 발생하였다. 2018년은 평년에 비해 소규모 C. polykrikoides 적조가 발생하였다. 본 연구결과 우리나라 연안의 영양염 감소와 기후변화로 인한 고수온은 적조 발생에 영향을 주는 것으로 판단된다.