• 환경생물
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• 제17권1호
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• pp.71-77
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• 1999

고리원전 주변 해역에서 1995년 11월부터 1996년 12월까지 총 13회의 현장조사를 수행하였다. 그 결과 식물플랑크톤은 총 162개 분류군(미동정종 포함)이 출현하였으며 그중 규조류가 총 120종이 출현하여 가장 많은 종수를 보였고 규질편모류 3종, 와편모조류 34종, 유글레나조류 2종, 녹조류 1종, 기타편모류 2종 등이 출현하였다. 규조류 종인 Skeletonema costatum은 연중 우점종으로 기록되었다. 식물플랑크톤 현존량의 월 평균값 변화는 최저 94 cells/ml(8월)에서 최고 1059 ce11s/m1(7월)에 이르며 2월과 7월에 현존량의 peak가 나타났다. 고리원전 주변해역에서는 온배수에 의한 영향이 계절에 따라 차별적으로 나타나고 겨울과 가을철에 한하여 1∼3 km의 수역에서 식물플랑크톤 현존량의 증가가 일어 날 수 있음을 나타내었고 여름철 식물플랑크톤 현존량은 온배수의 영향이 상당히 부정적임을 나타내었다.

• 해양환경안전학회지
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• 제19권1호
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• pp.85-92
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• 2013

최근 기후변화를 초래하는 화석연료의 사용을 감축하는 세계적 추세와 함께 에너지의 안정적 공급을 위해 많은 노력이 요구되고 있다. 또한 2012년부터는 500 MW 이상의 전기를 생산하는 에너지사업자는 신재생에너지 의무할당제의 적용을 받는다. 조류자원은 최근 각광을 받고 있는 신재생에너지이며, 이러한 조류자원은 매우 크지만 제한된 지역에 분포하고 있으므로 조류에너지를 효과적으로 이용하기 위해서는 반드시 기술적, 경제적인 측면의 평가가 요구된다. 그러므로 본 연구에서는 부남군도 해역에 부존하는 조류자원 실용화 기술개발을 위하여 조류에너지원에 대한 자료수집 등의 현황분석과 수치모델을 이용한 시뮬레이션 등을 통하여 조류에너지 분포도를 조사하고 이용 가능한 연간 에너지 생산량을 산정, 조류발전기를 모듈화 하여 최적의 조류발전단지 구성기술을 개발하고자 한다.

• ALGAE
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• 제28권2호
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• pp.173-183
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• 2013

Sodium hypochlorite (NaOCl) is widely used to disinfect seawater in power plant cooling systems in order to reduce biofouling, and in ballast water treatment systems to prevent transport of exotic marine species. While the toxicity of NaOCl is expected to increase by ongoing ocean acidification, and many experimental studies have shown how algal calcification, photosynthesis and growth respond to ocean acidification, no studies have investigated the relationship between NaOCl toxicity and increased $CO_2$. Therefore, we investigated whether the impacts of NaOCl on survival, chlorophyll a (Chl-a), and effective quantum yield in three marine phytoplankton belonging to different taxonomic classes are increased under high $CO_2$ levels. Our results show that all biological parameters of the three species decreased under increasing NaOCl concentration, but increasing $CO_2$ concentration alone (from 450 to 715 ${\mu}atm$) had no effect on any of these parameters in the organisms. However, due to the synergistic effects between NaOCl and $CO_2$, the survival and Chl-a content in two of the species, Thalassiosira eccentrica and Heterosigma akashiwo, were significantly reduced under high $CO_2$ when NaOCl was also elevated. The results show that combined exposure to high $CO_2$ and NaOCl results in increasing toxicity of NaOCl in some marine phytoplankton. Consequently, greater caution with use of NaOCl will be required, as its use is widespread in coastal waters.

• 한국환경농학회지
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• 제38권2호
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• pp.69-75
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• 2019

BACKGROUND: Measurement of electrical conductivity of saturated soil paste ($EC_e$) for assessment of soil salinity is time-consuming, and thus conversion of EC of 1:5 soil-water extract ($EC_{1:5}$) to $EC_e$ using a dilution factor may be of help to monitor salinity of huge number of soil samples. This study was conducted to evaluate the dilution factor for reclaimed tideland (RTL) soils of South Korea. METHODS AND RESULTS: Soil samples (n=40) were collected from four RTLs, and analyzed for $EC_{1:5}$, $EC_e$, and cation compositions of 1:5 soil-water extract. The dilution factor (8.70) was estimated by regression analysis between $EC_{1:5}$ and $EC_e$, and the obtained dilution factor was validated by applying to an independent data set (n=96) of $EC_{1:5}$ and $EC_e$. The $EC_e$ measured and predicted was strongly correlated ($r^2=0.74$, P<0.001), but $EC_e$ was overestimated by 16% particularly for the soils with high clay content and low sodium adsorption ratio (SAR). CONCLUSION: This study suggests that using the dilution factor to convert $EC_{1:5}$ to $EC_e$ is feasible method to monitor changes in the soil salinity of the study RTL. However, overestimation of $EC_e$ should be cautioned for the soils with high clay content and low SAR.

• 한국수산과학회지
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• 제55권3호
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• pp.310-318
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• 2022

Cnidium japonicum a biennial plant belonging to the family Umbelliferae, is a halophyte that grows in high-salinity areas of coastal sand dunes and sandy shores. This study was conducted to investigate the constituents, antioxidant activities, and physiological activities of C. japonicum. Mineral analyses revealed that potassium, sodium, calcium, and magnesium were the most prevalent minerals in C. japonicum. We used 80% ethanol, 80% methanol, and distilled water as solvents to prepare extracts from C. japonicum tissues, and the obtained extraction yields ranged between approximately 26% and 32%. Among the three extracts, the ethanol and methanol extracts had higher total polyphenol and flavonoid levels than the water extracts did. The antioxidant activities of methanol extracts were the highest among the various solvent extracts of C. japonicum as was the elastase/collagenase inhibitory activity. In contrast, the ethanol extract exhibited the highest tyrosinase inhibitory activity. Furthermore, the methanol extract possessed over 80% BACE1 (β-secretase) inhibitory activity at a final concentration of 20 ㎍/mL. Therefore, these results indicate that methanol and ethanol extracts of C. japonicum may be useful as antioxidant and functional substances in food and pharmaceutical material.

• 한국환경복원기술학회지
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• 제25권3호
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• pp.29-45
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• 2022

For biodiversity conservation, the importance of beta-diversity which is changes in the composition of species according to environmental changes has become emphasized. However, given the systematic investigation of species distribution and the accumulation of large amounts of data in the Republic of Korea(ROK), research on the spatialization of beta-diversity using them is insufficient. Accordingly, this research investigated the applicability of the Generalized Dissimilarity Modeling(GDM) to ROK, which can predict and map the similarity of compositional turnover (beta-diversity) based on environmental variables. A brief overview of the statistical description on using GDM was presented, and a model was fitted using the flora distribution data(410,621points) from the National Ecosystem Survey and various environmental spatial data including climate, soil, topography, and land cover. Procedures and appropriated spatial units required to improve the explanatory power of the model were presented. As a result, it was found that geographical distance, temperature annual range, summer temperature, winter precipitation, and soil factors affect the dissimilarity of the vegetation community composition. In addition, as a result of predicting the similarity of vegetation composition across the nation, and classifying them into 20 and 100 zones, the similarity was high mainly in the central inland area, and tends to decrease toward the mountainous areas, southern coastal regions, and island including Jeju island, which means the composition of the vegetation community is unique and beta diversity is high. In addition, it was identified that the number of common species between zones decreased as the geographic distance between zones increased. It classified the spatial distribution of plant community composition in a quantitative and objective way, but additional research and verification are needed for practical application. It is expected that research on community-level biodiversity modeling in the ROK will be conducted more actively based on this study.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4265-4271
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• 2022

Determination of ¹³⁷Cs, ⁴⁰K and ²¹⁰Po in water, bottom sediments and suspended matter of river systems of the Can Gio Biosphere Reserve, Vietnam was carried out. The average activity concentration of ¹³⁷Cs in waters of Ca Gau and Long Tau was 0.89 ± 0.14 and 1.08 ± 0.15 Bq m^-3 and was comparable to the levels of this radioisotope in waters of the East Sea. The activity concentration of ¹³⁷Cs in bottom sediments was 2.23 ± 0.81 and 3.63 ± 1.24 Bq kg^-1. The activity concentration of ¹³⁷Cs in water and bottom sediments could be characterized as low. So, the water areas of the Ca Gau and Long Tau rivers could be attributed to areas with insignificant pollution by technogenic radionuclides. The ²¹⁰Po activity concentration in bottom sediments of the Ca Gau and Long Tau rivers ranged from 9.2 ± 1.2 to 25.5 ± 2.1 Bq kg^-1, which is typical for river bottom sediments. Such values indicate the absence of anthropogenic enhancement of the entry of this radionuclide into the Can Gio river systems. The ⁴⁰K activity concentration varied within 467 ± 42-651 ± 39 Bq kg^-1 and represented typical values of potassium content in the bottom sediments of coastal water bodies, subject to a significant influence of the lithogenic component of suspended matter.

• Strategy21
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• 통권37호
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• pp.193-241
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• 2015

China, Japan and Korea are the world's top 10 energy consumers, and so very interested in the development of seabed hydrocarbon resources in order to meet their energy demands. The East China Sea is the tri-junction area where three countries' entitlements on the maritime boundaries are overlapped. There are abundant oil reserves in the East China Sea, and therefore competitions among countries are growing to get control of them. Although these countries have concluded the bilateral agreements to jointly develop resources in the East China Sea, they do not function as well. Because joint development and management of seabed petroleum resources can lead to stable development system, and to lower possibility of legal and political disputes, the needs for joint development agreement among three countries are urgent. Meanwhile, Northeast Asian seas are semi-closed seas, which are geographically closed and vulnerable to marine pollution. Moreover there are a lot of nuclear power plants in coastal area, and seabed petroleum resources are being developed. So it is likely to occur nuclear and oil spill accidents. Fukushima nuclear disaster and Bohai Bay oil spill accident in 2011 are the cases to exhibit the potential of major marine pollution accidents in this area. It is anticipated that the risks become higher because power plants and offshore oil platforms are extending gradually. Therefore, the ways to seek the joint marine environmental protection agreement focused on regulation of nuclear power plant and offshore oil platform have to be considered. In this paper, we try to find the way to make joint development and joint environmental protection agreement in Northeast Asian seas. We concentrate on the measure to drive joint development of seabed petroleum deposits in East China Sea's overlap area, despite of maritime delimitation and territorial disputes, and we try to drive joint marine environmental protection system to respond to marine pollution and accidents due to offshore oil platform and nuclear power plants. Through these consideration, we seek solutions to deal with lack of energy, disputes of maritime territorial and boundary delimitation, and marine pollution in Northeast Asia.

• Journal of Ecology and Environment
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• 제47권2호
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• pp.49-62
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• 2023

Background: Over the past three decades, gradual eustatic sea-level rise has been considered a primary exogenous factor in the increased frequency of flooding and biological changes in several salt marshes. Under this paradigm, the potential importance of short-term events, such as ocean storminess, in coastal hydrology and ecology is underrepresented in the literature. In this study, a simulation was developed to evaluate the influence of wind waves driven by atmospheric oscillations on sedimentary and vegetation dynamics at the Skallingen salt marsh in southwestern Denmark. The model was built based on long-term data of mean sea level, sediment accretion, and plant species composition collected at the Skallingen salt marsh from 1933-2006. In the model, the submergence frequency (number yr^-1) was estimated as a combined function of wind-driven high water level (HWL) events (> 80 cm Danish Ordnance Datum) affected by the North Atlantic Oscillation (NAO) and changes in surface elevation (cm yr^-1). Vegetation dynamics were represented as transitions between successional stages controlled by flooding effects. Two types of simulations were performed: (1) baseline modeling, which assumed no effect of wind-driven sea-level change, and (2) experimental modeling, which considered both normal tidal activity and wind-driven sea-level change. Results: Experimental modeling successfully represented the patterns of vegetation change observed in the field. It realistically simulated a retarded or retrogressive successional state dominated by early- to mid-successional species, despite a continuous increase in surface elevation at Skallingen. This situation is believed to be caused by an increase in extreme HWL events that cannot occur without meteorological ocean storms. In contrast, baseline modeling showed progressive succession towards the predominance of late-successional species, which was not the then-current state in the marsh. Conclusions: These findings support the hypothesis that variations in the NAO index toward its positive phase have increased storminess and wind tides on the North Sea surface (especially since the 1980s). This led to an increased frequency and duration of submergence and delayed ecological succession. Researchers should therefore employ a multitemporal perspective, recognizing the importance of short-term sea-level changes nested within long-term gradual trends.

• 한국해안·해양공학회논문집
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• 제26권5호
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• pp.300-313
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• 2014

파-지반의 상호작용 해석에 지금까지는 대부분 무한두께를 갖는 해저지반 상의 진행파와 무한두께 혹은 유한두께의 해저지반 상에서 완전중복파에 대해서만 해석해가 제안되어 있다. 본 연구에서는 임의반사율의 부분중복파동장에 선형파 이론과 유한두께를 갖는 해저지반에 Biot(1941) 3차원 압밀이론 및 지반탄성론에 기초한 유효응력 개념을 각각 적용하여 지반 내 동적응답에 관한 해석해를 새롭게 유도하며, 이에 수심과 반사율만을 변화시킴으로서 기존의 해석해가 간단히 얻어지기 때문에 그의 적용성이 보다 넓다. 본 해석해의 타당성은 무한지반 상의 진행파동장 및 완전중복파동장에 대한 Yamamoto et al.(1978) 및 Tsai & Lee(1994)의 해석해와 비교 검토로부터 검증된다. 또한, 본문에서는 유한깊이를 갖는 해저지반 상의 진행파동장, 완전중복파동장 및 임의반사율의 부분중복파동장에 대해 수심과 주기의 변화에 따른 본 해석해의 변화특성을 면밀히 검토한다. 이로부터 유한깊이의 지반은 무한두께의 경우와는 매우 상이한 지반응답(간극수압, 전단응력, 수평 및 연직 유효응력)을 나타내고, 반사율의 함수인 부분중복파동장에서 지반응답은 완전중복파동장에서의 값보다 일반적으로 작은 값을 나타낸다는 것을 확인할 수 있었다.