• Journal of Ecology and Environment
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• 제43권1호
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• pp.61-72
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• 2019

Background: Organic carbon stored in coastal wetlands, which comprises the major part of oceanic "blue carbon," is a subject of growing interest and concern. In this study, organic carbon storage in coastal wetlands and its economic value were estimated using the raw data of 25 studies related to soil carbon storage. Data were collected from three tidal flats (one protected and two developed areas) and two estuarine salt marshes (one protected and one restored area). Bulk density, soil organic matter content, and standing biomass of vegetation were all considered, with Monte Carlo simulation applied to estimate the uncertainty. Results: Mean carbon storage in two salt marshes ranged between 14.6 and $25.5kg\;C\;m^{-2}$. Mean carbon storage in tidal flats ranged from 18.2 to $28.6kg\;C\;m^{-2}$, with variability possibly related to soil texture. The economic value of stored carbon was estimated by comparison with the price of carbon in the emission trading market. The value of US $ $6600\;ha^{-1}$ is ~ 45% of previously estimated ecosystem services from fishery production and water purification functions in coastal areas. Conclusions: Although our study sites do not cover all types of large marine ecosystem, this study highlights the substantial contribution of coastal wetlands as carbon sinks and the importance of conserving these habitats to maximize their ecosystem services.

• 한국수산과학회지
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• 제16권4호
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• pp.299-304
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• 1983

제주해협 동쪽 입구에는 주년 대마난류 수괴인 설상 난수가 존재한다. 그러므로 이 설상 난수 때문에 동 해협 서쪽에서 유입하는 해수의 유향이 이 해협내에서 변화되 한국 남해 연안쪽을 향할 수 있어 제주해협내의 중, 저층수는 한국 남해 연안수 형성에 중요한 영향을 미칠 수 있다. 이 설상 난수는 동계에 강하고 하계에 약하므로 대마난류는 하계 보다 동계에 한국 남해 연안에 접근하며, 이 난류의 북쪽 경계도 거문도와 소리도 연안까지 자주 접근하고 있다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.153-153
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• 2022

Large-scale and accurate observations at fine spatial resolution through a means of remote sensing offer an effective tool for capturing rainfall variability over the traditional rain gauges and weather radars. Although satellite rainfall products (SRPs) derived using two major estimation approaches were evaluated worldwide, their practical applications suffered from limitations. In particular, the traditional top-down SRPs (e.g., IMERG), which are based on direct estimation of rain rate from microwave satellite observations, are mainly restricted with their coarse spatial resolution, while applications of the bottom-up approach, which allows backward estimation of rainfall from soil moisture signals, to novel high spatial resolution soil moisture satellite sensors over South Korea are not introduced. Thus, this study aims to evaluate the performances of a state-of-the-art bottom-up SRP (the self-calibrated SM2RAIN model) applied to the C-band SAR Sentinel-1, a statistically downscaled version of the conventional top-down IMERG SRP, and their integration for a targeted high spatial resolution of 0.01° (~ 1-km) over central South Korea, where the differences in climate zones (coastal region vs. mainland region) and vegetation covers (croplands vs. mixed forests) are highlighted. The results indicated that each single SRP can provide plus points in distinct climatic and vegetated conditions, while their drawbacks have existed. Superior performance was obtained by merging these individual SRPs, providing preliminary results on a complementary high spatial resolution SRP over central South Korea. This study results shed light on the further development of integration framework and a complementary high spatial resolution rainfall product from multi-satellite sensors as well as multi-observing systems (integrated gauge-radar-satellite) extending for entire South Korea, toward the demands for urban hydrology and microscale agriculture.

• 한국해양바이오학회지
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• 제5권4호
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• pp.40-45
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• 2011

Microalgae are one of the major, sustaining components of ecosystem processes and are responsible for biogeochemical reactions that drive our climate changes. Despite this, many marine microalgae are poorly described and little is known of their abundance and distribution along the coastal areas of Sooyoung Bay, Busan, South Korea. The present study has been conducted from November, 2011 to August, 2009 with the objective to provide an overview of the taxonomy diversity and abundance of microalgae along the coastal areas of the Sooyoung Bay. Water samples were collected from different sites, which were located by using a GPS tracker. Chlorophyll fluorescence of the water samples were measured by using ToxY-PAM dual-channel yield analyzer. The chlorophyll fluorescence values were relatively higher during the spring and summer and even in the region near to the sea port. Similarly the abundance of microalgae was higher near the port but diversity index had lower values. The temperature and pH values were same at all the sites. However, only the temperature varied during the sampling period, with higher values during summer and lower in winter. From the preliminary results, the following class of microalgae were found; Bacillariophyceae, Dinophyceae, Silicoflagellate and Cryptophyceae. With a future ongoing work, microalgae are being isolated to establish single cell culture and for identification using light microscopic observations, photography and molecular approaches.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.157-157
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• 2022

Recent decades have seen all over the world increasing drought in some regions and increasing flood in others. Climate change has been alarming in many regions resulting in degradation and diminution of available freshwater. The effect of global warming and overpopulation associated with increasing irrigated farming and valuable agricultural lands could be particularly disastrous for coastal areas like the one of Benin. The coastal region of Benin is under a heavy demographic pressure and was in the last decades the object of important urban developments. The present study aims to roughly study the general effect of climate change (Sea Level Rise: SLR) and groundwater pumping on Seawater intrusion (SWI) in Benin's coastal region. To reach the main goal of our study, the region aquifer system was built in numerical model using SEAWAT engine from Visual MODFLOW. The model is built and calibrated from 2016 to 2020 in SEAWAT, and using WinPEST the model parameters were optimized for a better performance. The optimized parameters are used for seawater intrusion intensity evaluation in the coastal region of Benin The simulation of the hydraulic head in the calibration period, showed groundwater head drawdown across the area with an average of 1.92m which is observed on the field by groundwater level depletion in hand dug wells mainly in the south of the study area. SWI area increased with a difference of 2.59km² between the start and end time of the modeling period. By considering SLR due to global warming, the model was stimulated to predict SWI area in 2050. IPCC scenario IS92a simulated SLR in the coastal region of Benin and the average rise is estimated at 20cm by 2050. Using the average rise, the model is run for SWI area estimation in 2050. SWI area in 2050 increased by an average of 10.34% (21.04 km²); this is expected to keep increasing as population grows and SLR.

• 한국해양학회지:바다
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• 제13권4호
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• pp.325-332
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• 2008

2007년 남해동부해역에서 발생한 Cochlodinium polykrikoides 적조의 발생, 진행 및 소멸현상을 식물플랑크톤, 물리 화학적 환경요소와 기상자료를 이용하여 분석하였다. 2007년 남해동부해역에서 C. polykrikoides 적조발생은 3단계로 특징 지을 수 있다. 첫 단계는 예년에 비해 예외적으로 강하게 지속된 남풍에 의해 남해중부해역에서 이미 발생한 C. polykrikoides 적조가 8월 초에서 8월 말 조사해역으로 간헐적으로 유입되면서 C. polykrikoides 개체수 변화가 크게 나타난 시기이다. 두 번째 단계는 8월 말에서 9월 중순 풍향이 남풍에서 북동풍으로 변화하여 외해수가 유입되고 적조발생 호적환경이 조성된 단계로 고밀도의 C. polykrikoides가 출현한다. 마지막 단계는 9월 중순이후 태풍 '나리'의 영향으로 많은 양의 폭우로 인한 연안해역의 저염분화가 C. polykrikoides의 호적 성장환경을 파괴되고, 경쟁 식물플랑크톤의 우점화로 C. polykrikoides가 소멸하는 시기이다. 이상의 결과들은 2007년 남해동부해역에서 고밀도로 장기간 지속된 C. polykrikoides 적조발생 기작을 설명 할 수 있을 것으로 판단된다.

• 수산해양기술연구
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• 제54권2호
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• pp.146-156
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• 2018

Acoustic surveys were conducted in the seas surround the South Korea (South Sea A, South Sea B (waters around the Jeju Island), West Sea and East Sea) in spring and autumn in 2016. First, the vertical and horizontal distributions of fisheries resources animals were examined. In most cases vertical acoustic biomass was high in surface water and mid-water layers other than South Sea A in autumn and West Sea. The highest vertical acoustic biomass showed at the depth of 70-80 m in the South Sea A in spring ($274.4m^2/nmi^2$) and the lowest one was 10-20 m in the West Sea in autumn ($0.4m^2/nmi^2$). With regard to the horizontal distributions of fisheries resources animals, in the South Sea A, the acoustic biomass was high in eastern and central part of the South Sea and the northeast of Jeju Island ($505.4-4099.1m^2/nmi^2$) in spring while it was high in eastern South Sea and the coastal water of Yeosu in autumn ($1046.9-2958.3m^2/nmi^2$). In the South Sea B, the acoustic biomass was occurred high in the southern and western seas of Jeju Island in spring ($201.0-1444.9m^2/nmi^2$) and in the southern of Jeju Island in autumn ($203.7-1440.9m^2/nmi^2$). On the other hand, the West Sea showed very low acoustic biomass in spring (average NASC of $1.1m^2/nmi^2$), yet high acoustic biomass in the vicinity of 37 N in autumn ($562.6-3764.2m^2/nmi^2$). The East Sea had high acoustic biomass in the coastal seas of Busan, Ulsan and Pohang in spring ($258.7{\sim}976.4m^2/nmi^2$) and of Goseong, Gangneung, Donghae, Pohang and Busan in autumn ($267.3-1196.3m^2/nmi^2$). During survey periods, fish schools were observed only in the South Sea A and the East Sea in spring and the West Sea in autumn. Fish schools in the South Sea A in spring were small size ($333.2{\pm}763.2m^2$) but had a strong $S_V$ ($-49.5{\pm}5.3dB$). In the East Sea, fish schools in spring had low $S_V$ ($-60.5{\pm}14.5dB$) yet had large sizes ($537.9{\pm}1111.5m^2$) and were distributed in the deep water depth ($83.5{\pm}33.5m$). Fish schools in the West Sea in autumn had strong $S_V$ ($-49.6{\pm}7.4dB$) and large sizes ($507.1{\pm}941.8m^2$). It was the first time for three seas surrounded South Korea to be conducted by acoustic surveys to understand the distribution and aggregation characteristics of fisheries resources animals. The results of this study would be beneficially used for planning a future survey combined acoustic method and mid-water trawling, particularly deciding a survey location, a time period, and a targeting water depth.

• 한국수산과학회지
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• 제56권3호
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• pp.315-323
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• 2023

The maturity and spawning of the large yellow croaker Larmichthys crocea were investigated using samples randomly collected in the Jeju coastal area, Korea. We analyzed monthly changes in maturity stages, gonadosomatic index (GSI), and egg diameter. Additionally, we verified fecundity by size class and total length (TL) at sexual group maturity at 50%, 75%, and 97.5%, as well as by sex ratio (female vs. male). The overall sex ratio of females to males was 1:0.42. The GSI values showed a peak in October, but the spawning season, revealed by the microscopic analysis of gonadal tissue of L. crocea was from October 2021 to March 2022, with the main spawning period from October to November. The fecundity (F) of female L. crocea ranged from 39,232 eggs at 20 to 29.9 cm to 251,003 eggs at 50 to 59.9 cm, with the relationship between TL and F being 80.244TL-1641.6. In females, TL at 50%, 75%, and 97.5% maturity was 22.4, 24.3, and 29.0 cm, respectively.

• 대한원격탐사학회지
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• 제31권4호
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• pp.281-291
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• 2015

Sun glint correction methods of hyperspectral data that have been developed so far have not considered the various situations and are often adequate for only certain conditions. Also there is an inaccurate assumption that the signal in NIR wavelength is zero. Therefore, this study attempts to analyze the NIR spectral properties of sun glint effect in coastal waters. For the analysis, CASI-1500 airborne hyperspectral data, bathymetry data and in-situ data obtained at coastal area near Sin-Cheon, Jeju Island, South Korea were used. The spectral characteristics of radiance and reflectance at the five NIR wavelengths (744 nm, 758 nm, 772 nm, 786 nm, and 801 nm) are analyzed by using various statistics, spatial and spectral variation of sun-glinted area under conditions of the bottom types of benthos, barren rocks and sand with similar water depth. Through the quantitative analysis, we found that the relation of water depth or bottom type with sun glint is relatively less which is a similar result with the previous studies. However the sun glint are distributed similarly with the patterns of the direction of wave propagation. It is confirmed that the areas with changed direction of wave propagation were not affected by the sun glint. The spatial and spectral variations of radiance and reflectance are mainly caused by the effect of sun glint and waves. The radiance or reflectance of more sun-glinted areas are increased approximately 1.5 times and the standard deviations are also increased three times compared to the less sun glinted areas. Through this study, the further studies of sun glint correction method in coastal water using the patterns of wave propagation and diffraction will be placed.

• 한국환경과학회지
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• 제9권3호
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• pp.215-221
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• 2000

The relationship between the distribution of sea surface temperature(SST) and dinoflagellate(Cochlodinium polykrikoides) bloom areas were studied. The SST data were derived from the infrared channels of AVHRR(Advanced Very High Resolution Radiometer) sensor on NOAA(National Oceanic and Atmospheric Administration) 12 and 14 satellites during 1995-1998. The initial water temperature at C. polykrikoides bloom was about 21${\circ}C$ at the coastal areas of the South Sea and along the shore of the East Sea of Korea during the summer season of 1995. The northern limit of red tides was coincident with that of 21${\circ}C$ isothermal line in the East Sea. The red tides that initially bloomed at the coast of Pohang on September 21, 1995 moved to the coast of Uljin on September 26, 1995. The skipped appearance of the red tides in the areas between Pohang and Uljin was due to the East Korean Warm Current, which was moving offshore from Pohang to approach to Uljin. The cold water which was formed by tidal front in the western coast of the South Sea and by upwelling water from deep layer in the southeastern coast of the Korean peninsula played a role in blocking the spreading of red tides during summer season in 1997 and 1998. In conclusion, the distribution of red tides appeared to be dependent on the initial water temperature at red tides bloom. The SST at the red tides varied from 21${\circ}C$ to 25${\circ}C$; 21${\circ}C$, 23${\circ}C$, 24 and 24-25${\circ}C$ in 1995, 1996, 1997 and 1998, respectively.