• Korean Journal of Microbiology
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• v.42 no.1
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• pp.7-11
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• 2006

To see effect of marine rock powder and fungal culture supernatant, we analyzed the biodegradation rates of harmful marine dinoflagellate, Heterosigma akashiwo and Prorocentrum minimum for developing the effective control methodology of algal bloom. Relatively low removal rates were observed in the treatment of marine rock powder or buffer solution alone. However, the lysis of H. akashiwo and P. minimum was enhanced in the combined treatments of marine rock powder with fungal supernatant. The effective concentration and exposure time of fungal supernatant for the lysis of H. akashiwo and P. minimum were 5 ml/l and 30 minutes, respectively. These results suggest that the fungal supernatant may be a biocontrol agent for the control of algal blooms in seawater.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 1997.10a
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• pp.52-53
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• 1997

수역의 유기오염 개선을 위하여 생활하수, 산업폐수 등의 저하시키는데 주안점을 두어왔으나 공공수역에서의 제거되지 않은 질소와 인의 유입으로 부영양화가 진행되어 하천에는 남조류가 대량발생하고 해역에는 적조가 광역에서 발생하여 큰 사회문제가 되고 있고, 질소와 인의 유입으로 인한 자생 COD가 전체COD의 약 절반을 차지하고 있는 실정이다. 따라서 앞으로의 수질을 개선하기 위해서는 조류증식의 제한인자인 질소와 인의 규제가 필요할 뿐만아니라 하수처리장에 고차처리를 적용하거나, 해양의 회석자용을 이용한 Ocean을 적용하여 연안해역 수질을 관리해야 할 것이다. 따라서 본 연구는 수영만을 대상으로 Ocean Outfall과 폐수처리시절을 적절하게 조합하기 위해서 3차원 생태계모델을 적용하여 유기물질 뿐만 아니라 영양염류인 질소와 인의 농도를 예측하여 환경기준을 만족시키고 비용을 최소화 할 수 있는 폐수처리공법과 해중방류관의 위치를 선정하고자 하였다. 본 연구결과 수영만의 1994년 COD는 II등급, DIN과 DIP는 III등급이었다. 현재의 활성슬러지공법으로 질소와 인을 제거하지 않고 방류할 경우 2001년에 는 하수처리량의 증가로 인해 COD의 경우 1994년 보다 조금 감소하지만 DIN 과 DIP는 1994년과 같은 III등급을 유지하였다. 고도처리공법을 도입할 경우 COD의 농도는 광안리와 해운대해수욕장에서 I등급을 보이고, DIP의 농도도 수영만 전체에서 강등급을 보이지만, DM의 농도는 광안리해수욕장에서 II등급, 해운대해수욕장에서 IH등급을 보였다 하수처리장 유출수를 Ocean Outfall을 이용하여 하수처리장으로부터 4km에 서 방류할 경우의 COD농도는 I등급을 보이고, DE 농도도 광안리와 해운대해 수욕장에서는 I등급을 보이고, DU의 농도는 ll등급을 보여 수질이 개선된 것 을 볼 수 있다. 이상에서와 같이 광안리와 해운대해수욕장의 해역환경기준 ll등급을 만족 하는 하수처리방법은 Ocean Outfall이었다. 수영하수처리장에 인을 처리하기 위한 화학적 침전법의 경우 956억원이 소요되고, 질소를 제거하기 위한 질소제거공정을 추가 건설 할 경우는 2181억원이 전요된다. 그리고 두공정을 같이 건설할 경우에는 3137억원의 비용이 소요된다 수영하수처리장에서 4km 거리와 관경을 2m의 Ocean Outfall 건설비용은 325 억원 정도가 소요되는 것으로 산출되었다. 고차처리시 증가되는 비용으로 건설할 수 있는 Ocean Outfall의 길이는 인 제거공정을 첨가하는 경우에는 18km을 건설할 수 있고, 질소제거공정을 첨가 하는 경우에는 46km를 건설할 수 있는 것으로 산출되었다.

• Smart Media Journal
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• v.11 no.9
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• pp.56-63
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• 2022

Recently, the frequency and range of algae occurrence in major rivers and lakes are increasing due to the increase in water temperature due to climate change, the inflow of excessive nutrients, and changes in the river environment. Abnormal algae include green algae and red algae. Green algae is a phenomenon in which blue-green algae such as chlorophyll (Chl-a) in the water grow excessively and the color of the water changes to dark green. In this study, a 3D virtual world of digital twin was built to monitor and control water quality information measured in ecological rivers and lakes in the living environment in real time from a remote location, and a sensor measuring device for water quality information based on the Internet of Things (IOT) sensor. We propose to build a smart water environment service platform that can provide algae warning and water quality forecasting by predicting the causes and spread patterns of water pollution such as algae based on AI machine learning-based collected data analysis.

• Journal of Life Science
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• v.15 no.2 s.69
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• pp.225-230
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• 2005

The aim of this study was to examine the fluctuation in phytoplankton assemblages with regarding to environmental conditions and nutrients, which were surveyed quarterly over the fours seasons (February, May, July, and October). In turn, an understanding of biological effects should provide insights into a wide range of initiated Cochlodinium blooms in Narodo. Sampling was carried out throughout 2001 on the coasts of Busan (St. 1), Yeosu (St. 2), Narodo (St. 3), Kohung (St. 4), and Kwangdo (St. 5). The maximum surface water temperature was recorded in July, and it ranged from 20 to $22^{\circ}C$. Salinity showed no great variation, which maintained itself in the range of 29-34 psu. The maximum surface salinity was recorded in February, which was about 34 psu. The chlorophyll $\alpha$ concentration of the surface water ranged from 0.01 to $1.3\;{\mu}g\;1^{-1}$. The concentrations of $NH_{4}-N $ were persistently high from February to October; in particular, the peak was observed at St. 1 in February and May (0.15 and $0.19\;{\mu}mol\;1^{-1}$, respectively), while it was detected at St. 2 in July and October (0.22 and $2.2\;{\mu}mol\;1^{-1}$ respectively). Similar trends to those for $NH_4-N $ were observed in the concentrations of $NO_{2}-N$ and $NO_{3}-N$. In contrast to nitrogen, a distinct peak of $NO_{4}-P$ at St. 3, 4, and 5 was observed throughout year $(0.01-0.1\;{\mu}mol\;1^{-1}$ except for October. At St. 1 encounter a peak of cell number of 30,000 and $13{\times}10^3$ cells $1^{-1}$, respectively, in July and October. During the period of this study, the majority of the taxa were diatoms. The dinoflagellates were rather abundant after February, in particular at St. 3, 4, and 5 which attained an abundance of $10\~20\%$without marked fluctuation during the period of this study. At St. 3, the highest average cell width, $178.11\;{\mu}m$, was recorded: the highest cell length, $337.72\;{\mu}m$, was measured in July. Consequently, dinoflagellates bloom in July at Narodo influenced by warm water current are not only associated with a desirable development of cell morphometric characteristics, but also with the health growth of C. polykrikoides. During the period of this study, warm water currents caused an increased water temperature in Narodo, but did not change the amount of nutrients.

• Journal of Life Science
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• v.18 no.9
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• pp.1194-1201
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• 2008

Water temperature-dependent fluctuations of biochemical and molecular activities in the harmful dinoflagellate, Cochlodinium polykrikoides were studied. In terms of genomic DNA concentration, a similar value of 0.6 was observed at $12^{\circ}C$ and $15^{\circ}C$. However, DNA significantly increased beyond $18^{\circ}C$ (p<0.05), to a maximum of 1.8 at $24^{\circ}C$. DNA concentration significantly decreased to 0.6. The concentrations of RNA and total protein were likely at their highest values of 1.7 and 0.07 ${\mu}g$ $ml^{-1}$ at $24^{\circ}C$, respectively. RNA and total protein concentrations began to increase at $15^{\circ}C$. Oxygen availability between lower and higher temperatures was significantly different and increased from $18^{\circ}C$ according to light intensity, regardless of wavelengths (p<0.05). At $24^{\circ}C$, the highest value of the maximum electron transport rate ($ETR_{max}$), ranging from 537.9 (Ch 1) to 602.5 ${\mu}mol$ electrons $g^{-1}$ Chl ${\alpha}s^{-1}$ (Ch 4), was also apparent. Nitrate reductase (NR) and ATPase activities were at their highest values of 0.11 ${\mu}mol$ $NO_{2}^{-}$ ${\mu}g^{-1}$ Chl ${\alpha}h^{-1}$ and 0.78 pmol 100 $mg^{-1}$ at $24^{\circ}C$, respectively. In an analysis of CHN, the concentration of C and N also significantly increased (p<0.05). Most of the measurements for the cellular activities at $27^{\circ}C$, however, were less than at $24^{\circ}C$. These results suggest that the sub-cellular activities of C. polykrikoides are sensitive to changes in water temperature. It may be desirable to estimate at $18^{\circ}C$ the initiation of the massive blooming development of C. polykrikoides. In nature, it will be very difficult to maintain the massive blooms beyond $24^{\circ}C$ because of a possibly significant decrease in molecular activity of C. polykrikoides.

• Journal of Navigation and Port Research
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• v.36 no.6
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• pp.443-448
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• 2012

As a basic data to build a countermeasures against coastal disaster, the conscious survey of people living around the coastal are is needed. This study performed the conscious survey on 5 islands located at Korean southeast ocean including Youngdo of Busan. Among many respondents, 503 effective answers are got and followings are the analyzed results. Among the various kinds of disasters, especially the typhoon(28%), storm surge(19%), earthquake(15%) are selected as menacing disasters in mind to coastal inhabitants. Typhoon(60%) and storm surge(21%) were the representative disasters that the coastal inhabitants experienced. 67% among the respondents get the disaster-related information from TV and/or commercial medias, and other 21% depend on their own experiences. Although 33% of respondents attended the disaster-related training and the training time was less than 2 hours, they answered the training was very helpful. Over 85% among the respondents answered they will evacuate if a disaster occur, but only 19% know the evacuee shelter(s). Except the foods, various living goods are selected and willing to carry with for living at shelter if they have to evacuate.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.448-452
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• 2010

The traditional Aids to Navigations(AtoN) have been ensuring the safety of ships by indicating the passage and dangers by depending on the flashing lights. But the more the industrial complex behind port which is all over the country involving the Ulsan port developed, the more the lights behind port is stronger, and then the distinguishment of the signal of AtoN from the lights behind port is more difficult. And It is urgently needed to prepare the counterplan about the ensurement of safety because the authorities levels up the limit tonnage of the ships which are sail in and out during night to improve the operation of port through reducing of the traffic jam So, the method of direct lighting like LED non-neon is applied to unmanned lighthouses or light beacon, and the LED flashing number plate is applied to light buoys whose light power is weaker than to improve distinguishment and to be easy positioning of ships. As a result, the users of Ulsan port comment favorably on this item and the development of AtoN must be continuos to overcome the lights behind port.

• Journal of Environmental Science International
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• v.19 no.12
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• pp.1385-1395
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• 2010

Harmful dinoflagellate Cochlodinium polykrikoides blooms have been frequently occurred in coastal areas of the East Sea since 1995. We compared the oceanic conditions in years 1995, 2001 and 2003 when the C. polykrikoides bloom was strong, and in years 1998 and 2004 when the C. polykrikoides bloom was not appeared. We studied temporal and spatial variation of upwelling and geostrophic currents on the western channel of Korean Strait, an entrance of the East Sea. The period and occurrence area of C. polykrikoides bloom was depended on variation of upwelling in summer. In the distributions of geostrophic current, southward current was dominant near the coast in August, 1998 and 2000. Whereas northward current was dominant near and off the coast in August, 1995 and 2003 which the C. polykrikoides bloom was strong. When compared dominant phytoplankton of the coastal areas in each year, Kuroshio indicator species Proboscia alata and Chaetoceros affine were dominant, respectively, in 2001 and 2003 at every stations. However, the dominant species was variable at each coastal area in 1998 and 2000. In 2003, the abundance of Sagitta elegans which is known as the cold water indicator was low, but the abundance of S. enflata, warm water indicator, was very high in Gangneung compared to Sokcho. It seemed that the distribution of S. elegans is restricted by strong warm water current. In conclusion, it was estimated that the distribution of C. polykrikoides bloom in the coastal area of the East Sea was closely related with the strength of East Korea Warm Current and upwelling.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.6
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• pp.825-835
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• 1994

The distributions of temperature, salinity, dissolved oxygen, chemical oxygen demand, dissolved inorganic nitrogen and phosphate in the Yellow Sea are described from data collected in June and July, 1994. Based on the observations of water temperature and salinity, the fresh waters originated from the Changjiang River were found to affect the waters adjacent to Cheju Island. In the light of the distributions of dissolved oxygen and chemical oxygen demand, the western part of the Yellow Sea was worse in water quality than the eastern part. Based on data of nutrients, eutrophication indices of the western part were higher than those of the eastern part in summer. It is concluded that the western part of the Yellow Sea appeared to receive high pollution loads from rivers and was evaluated to have high potentiality of red tide occurrence.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.508-514
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• 2017

Water-bloom and red tide due to eutrophication have been overgrown and have caused various environmental problems. Recently, however, research on bid-diesel that can utilize algae as an energy source has been actively carried out. In particular, many studies variously have been conducted to utilize algal photosynthesis oxygen as a supply method for reducing the energy by an air blower in MWTP. In this study, a lab scale algae-nitrification reactor was operated to replace the oxygen required for nitrogen removal and the operation period was largely divided into three sections. In the first section, ammonia nitrogen removal efficiency was 24 ~ 38% according to the MLSS (Mixed Liquer Suspended Solid) concentration. In the second section, ammonia nitrogen removal efficiency was 38 ~ 50% according to the micro-algae concentration and in the last section ammonia nitrogen removal efficiency was 61 ~ 80% according to HRT (Hydraulic Retention Time). As a result, as the MLSS decreased and algae biomass increased, the ammonia nitrogen removal efficiency tended to increase, but the effect of Algae biomass was greater than that of MLSS.