• ALGAE
• /
• 제26권2호
• /
• pp.141-152
• /
• 2011

The present study describes the morphology, taxonomy, and distribution of species belonging to the diatom genus Rhizosolenia in Korea's marine coastal waters. From September 2008 to February 2010, we collected phytoplankton samples at 30 sites along the Korean coastline and studied them by light and scanning electron microscopy. We found 6 rhizosolenid genera in our samples: Rhizosolenia, Dactyliosolen, Guinardia, Pseudosolenia, Proboscia, and Neocalyptrella. In the present paper, we studied the following rhizosolenid species and compared them with congeners: R. pungens, R. fallax, R. imbricata, Rhizosolenia sp. 1, and Rhizosolenia sp. 2. The morphology of R. pungens exhibits important diagnostic characteristics in its girdle segment structure in the column and in its external process. To distinguish R. fallax and R. imbricata, the most important characteristics are the striation and the velum structure. R. pungens occurred in our samples all along the Korean coast. Only rarely did we find R. imbricata in the samples and at low abundance. We recorded R. fallax, Rhizosolenia sp. 1 and Rhizosolenia sp. 2 for the first time in Korean waters, but they rarely occurred.

• 지질공학
• /
• 제26권4호
• /
• pp.561-570
• /
• 2016

온양지역 온천수의 수질특성을 파악하기 위하여 2011년과 2016년에 24개 온천수의 수질을 분석한 결과 5년 동안 수온과 수질에는 큰 변화가 없었다. 2016년 온천수의 수온과 $SiO_2$, F와는 정의 상관관계($r^2=0.60$, 0.47)를, Ca, Mg, Cl, $SO_4$, $HCO_3$, EC와는 부의 상관관계($r^2=0.50$, 0.11, 0.50, 0.63, 0.23, 0.51)를 나타낸다. 온천수의 수온과 pH는 양의 상관관계, DO와는 음의 상관관계를 보여 온양지역 온천수는 심부 기원임을 지시한다. 온천수 수질 유형은 대부분이 심부기원인 $Na-HCO_3$ 형으로 분류되나 일부 온천공은 $Na(Ca)-HCO_3$ 형으로도 분류되어 천부 지하수의 유입특성도 보인다.

• 한국토양비료학회지
• /
• 제16권1호
• /
• pp.7-13
• /
• 1983

미(美) New Mexico주(州)에 많이 분포(分布)하는 Sheppard사토(砂土), Doak사양토(砂壌土), Lea사질식양토(砂質埴壌土) 및 Glendale식토(埴土)를 대상(対象)으로 관개수질(潅漑水質)에 따른 토양(土壌)의 투수성(透水性) 변화(変化)를 구명(究明)하기 위(為)하여 T.D.N. $1,250{\sim}15,000mg/{\ell}$인 염류수(塩類水)와 증류수(蒸溜水)를 관수(潅水)하여 실내(室內)에서 수리전도도(水理伝導度)를 측정(測定)하였다. 염류수(塩類水)가 유일(唯一)한 관개수원(潅漑水源)일 때의 수리전도도(水理伝導度)는 염농도변화(塩濃度変化)에 의한(依) 영향(影響)을 별(別)로 받지 않았으나 토양특성별(土壌特性別)로는 Sheppard사토(砂土)가 Glendale 식토(埴土)보다 투수성(透水性)이 매우 높았다. 염류수(塩類水)로 기(旣) 관개(潅漑)된 토양(土壌)에 양질(良質)의 관개수(潅漑水) 즉(卽) 증류수(蒸溜水) 처리(処理)는 수리전도도(水理伝導度)를 현저(顯著)게 감소(減少)시켰는데 이것은 사질(砂質)~양질계(壌質系) 토양(土壌)의 경우(境遇) 점토(粘土)의 분산(分散) 또는 장(長) 단거리(短距離) 이동(移動)에 의(依)한 Conducting pore의 봉쇄(封鎖)이며 식질계(埴質系) 토양(土壌)은 점토(粘土)의 팽창(膨脹)이 주(主)된 원인(原因)이었던 것으로 판단(判断)된다. 따라서 주(主) 관개수원(潅漑水源)이 염류수(塩類水)이고 자연강우(自然降雨)가 수반(隨伴)되어도 사질계(砂質系) 토양(土壌)에서는 문제점(問題点)이 없겠으나 식질계(埴質系) 토양(土壌)은 투수성(透水性) 감소(減少)에 의(依)한 염해유발(塩害誘発)의 가능성(可能性)을 내포(內包)하고 있으므로 관개시(潅漑時) 고려(考慮)되어야 한다.

• 수산해양기술연구
• /
• 제55권3호
• /
• pp.217-232
• /
• 2019

It was turned out by shrimp beam trawl monthly survey from March, 2015 to February, 2016 that different species composition and abundance of the fish assemblages in Sacheon Bay and coastal waters off Namhae, Korea were compared. As a result of monthly measured sea temperature and salinity of Sacheon Bay and coastal waters off Namhae, sea temperature of both areas was changed seasonally; however, differences in sea temperature occurred during certain periods depending on the region. Salinity was generally low in Sacheon Bay affected by fresh water, and both areas was low in summer and high in winter. A total of 73 species representing 37 families were collected in Sacheon Bay. The dominant fish species in terms of numbers and biomass were Liparis tanakae, $23,077inds./km^2$, $332.1kg/km^2$. A total of 91 fish species representing 49 families were collected in coastal waters off Namhae. The dominant fish species in terms of numbers were Leiognathus nuchalis, $139,683inds./km^2$ and biomass were Chelidonichthys spinosus, $1,078.6kg/km^2$. Analysis of dendrogram of the clustering showed that Sacheon Bay and coastal waters off Namhae were distinctive featured (global R = 0.691, p = 0.017). And except of summer season (July-October), there was a distinctive feature seasonally (global R = 0.844, p = 0.001). The fish species that appeared in common in both areas, where fish species caught in Sacheon Bay, an important inner bay,were smaller than those caught in coastal waters off Namhae appeared. It presented that Sacheon Bay plays a more important role in spawning and nursery ground for fisheries resource than coastal waters off Namhae, Korea.

• ALGAE
• /
• 제33권1호
• /
• pp.21-35
• /
• 2018

The phototrophic dinoflagellate genus Scrippsiella is known to have a worldwide distribution. Here, we report for the first time, the occurrence of Scrippsiella lachrymosa in Korean waters. Unlike the other stains of S. lachrymosa whose cultures had been established from cysts in the sediments, the clonal culture of the Korean strain of S. lachrymosa was established from motile cells. When the sulcal plates of S. lachrymosa, which have not been fully described to date, were carefully examined using scanning electron microscopy, the Korean strain of S. lachrymosa clearly exhibited the anterior sulcal plate (s.a.), right sulcal plate (s.d.), left sulcal plate (s.s.), median sulcal plate (s.m.), and posterior sulcal plate (s.p.). When properly aligned, the large subunit (LSU) rDNA sequence of the Korean strain of S. lachrymosa was ca. 1% different from those of two Norwegian strains of S. lachrymosa, the only strains for which LSU sequences have been reported. The internal transcribed spacer (ITS) rDNA sequence of the Korean strain of S. lachrymosa was also ca. 1% different from those of the Scottish and Chinese strains and 3% different from those of the Canadian, German, Greek, and Portuguese strains. Thus, the Korean S. lachrymosa strain has unique LSU and ITS sequences. The abundances of S. lachrymosa in the waters of 28 stations, located in the East, West, and South Sea of Korea, were quantified in four seasons from January 2016 to October 2017, using quantitative real-time polymerase chain reaction method and newly designed specific primer-probe sets. Its abundances were >$0.1cells\;mL^{-1}$ at eight stations in January and March 2016 and March 2017, and its highest abundance in Korean waters was $26cells\;mL^{-1}$. Thus, S. lachrymosa has a nationwide distribution in Korean waters as motile cells.

• 한국환경과학회지
• /
• 제11권7호
• /
• pp.627-636
• /
• 2002

While typhoons were passing by the coastal and offshore waters around the Korean peninsula, the variations of the sea surface temperature (SST) were studied. To study on the variation, the data related to the 22 typhoons among 346 typhoons which occurred in the western Pacific during 1990∼1999, daily measured field SSTs at coastal and offshore, and imageries from advanced very high resolution radiometer on NOAA satellite during 1990∼1999 were used. The average variations of the SSTs were -0.9℃ at coastal waters and -2℃ at offshore around the Korean peninsula while the typhoons were passing by. In very near coastal waters from the land, the SST was not changed because the bottom depth of the coastal waters was shallower than the depth of thermalcline, while the typhoon was passing. The temporal and spatial variation of SSTs at coastal waters in summer were depended on the various types of the typhoons＇paths which were passing through the Korean peninsula. When a typhoon passed by the western parts including the Yellow Sea of the Korean peninsula upwelling cold water occurred along the eastern coastal waters of the peninsula. The reason was estimated with the typhoon that was as very strong wind which blew from south toward north direction along the eastern shore of the peninsula, led to the Ekman transport from near the eastern coastal area toward the offshore. While cold water was occurring in the eastern coast, a typhoon passed over the coastal area, the cold water disappeared. The reason was estimated that the cold water was mixed up with the surrounding warm water by the effect of the typhoon. While a cold water was occurring in the eastern coast, a typhoon passed by the offshore of the eastern coast, there were the increasing of the SST as well as the disappearing of the cold water. While a typhoon was passing by the offshore of the eastern coast, the cold water which resulted from the strong tidal current in the western coast of the peninsula was horizontally spread from the onshore to the offshore. We think that the typhoon played the role of the very strong wind which was blowing from north toward south. Therefore, the Ekman transport occurred from the onshore toward the offshore of the western coast in the Korean peninsula.

• 수산해양기술연구
• /
• 제54권3호
• /
• pp.217-223
• /
• 2018

Overfishing capacity has become a global issue due to over-exploitation of fisheries resources, which result from excessive fishing intensity since the 1980s. In the case of Korea, the fishing effort has been quantified and used as an quantified index of fishing intensity. Fisheries resources of coastal fisheries in the Korean waters of the East Sea tend to decrease productivity due to deterioration in the quality of ecosystem, which result from the excessive overfishing activities according to the development of fishing gear and engine performance of vessels. In order to manage sustainable and reasonable fisheries resources, it is important to understand the fluctuation of biomass and predict the future biomass. Therefore, in this study, we forecasted biomass in the Korean waters of the East Sea for the next two decades (2017~2036) according to the changes in fishing intensity using four fishing effort scenarios; $f_{current}$, $f_{PY}$, $0.5{\times}f_{current}$ and $1.5{\times}f_{current}$. For forecasting biomass in the Korean waters of the East Sea, parameters such as exploitable carrying capacity (ECC), intrinsic rate of natural increase (r) and catchability (q) estimated by maximum entropy (ME) model was utilized and logistic function was used. In addition, coefficient of variation (CV) by the Jackknife re-sampling method was used for estimation of coefficient of variation about exploitable carrying capacity ($CV_{ECC}$). As a result, future biomass can be fluctuated below the $B_{PY}$ level when the current level of fishing effort in 2016 maintains. The results of this study are expected to be utilized as useful data to suggest direction of establishment of fisheries resources management plan for sustainable use of fisheries resources in the future.

• 대한원격탐사학회지
• /
• 제33권2호
• /
• pp.213-230
• /
• 2017

위성기반 적조 탐지 알고리즘들은 특정 해역, 적조 종을 중심으로 개발되어 왔다. 하지만 한반도 주변해역의 빠르고 정확한 적조 감시를 위해서는 한반도 주변의 전 발생 해역과 다양한 적조 종을 대상으로 한 연구가 필수적이다. 본 연구에서는 한반도 주변해역을 대상으로 GOCI 영상을 활용하여 적조 영역의 스펙트럼 특성과 위성기반 적조 탐지 알고리즘의 적합성을 분석하였다. 그 결과, 적조 종들의 클로로필 함량과 적조가 출현하는 해역의 탁도에 따라서 스펙트럼 특성이 달라졌다. 또한 기존 적조 탐지 알고리즘을 GOCI 영상에 적용하였으며, 이를 통해 기존 임계값으로는 적조 영역 추출에 한계가 있음을 알 수 있었다. 이를 개선하기 위해 적조 종들을 클로로필 함량의 차이에 따라 두 그룹으로 나누어 적조 감시 체계를 제시하였다. 총 5 단계를 거쳐 적조 영역과 비적조 영역을 구분하였으며, 적조 속보를 기준으로 했을 경우 최종 추출된 적조영역이 기존 알고리즘으로 추출된 영역에 비해 적절한 결과를 나타냈다. 이러한 적조 감시 체계를 활용한다면 한반도 주변의 모든 해역과 다양한 적조 종에 대한 빠르고 정확한 감시로 인해 효율적인 적조 감시가 가능할 것이다.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제7권1호
• /
• pp.63-77
• /
• 2002

Salinization is an important environmental problem encountered in coastal aquifers. In order to evaluate the salinization problem in the western coastal area of Korea, we have performed a regional hydrochemical study on shallow well groundwaters (N=229) collected within 10 km away from the coastline. The concentrations of analyzed solutes are very wide in range, suggesting that the hydrochemistry is controlled by several processes such as water-rock interaction, seawater mixing, and anthropogenic contamination. Based on the graphical interpretation of cumulative frequency curves for some hydrochemical parameters (esp., $Cl^{-}$ and ${NO_3}^-$), the collected water samples were grouped into two major populations (1) a background population whose chemistry is predominantly affected by water-rock interaction, and (2) an anomalous population which records the potential influences by either seawater mixing or anthropogenic pollution. The threshold values obtained are 34.7 mg/l for $Cl^{-}$ and 37.2 mg/l for ${NO_3}^-$, Using these two constituents, groundwaters were further grouped into four water types as follows (the numbers in parenthesis indicate the percentage of each type water) : (1) type 1 waters (38%) that are relatively poor in $Cl^{-}$ and ${NO_3}^-$, which may represent their relatively little contamination due to seawater mixing and anthropogenic pollution; (2) type 2 waters (21%) which are enriched in $Cl^{-}$, Indicating the considerable influence by seawater mixing; (3) ${NO_3}^-$-rich, type 3 waters (11%) which record significant anthropogenic pollution; and (4) type 4 waters (30%) enriched in both $Cl^{-}$ and ${NO_3}^-$, reflecting the effects of both seawater mixing and anthropogenic contamination. The results of the water type classification correspond well with the grouping on a Piper's diagram. On a Br x $10^4$versus Cl molar ratio diagram, most of type 2 waters are also plotted along or near the seawater mixing line. The discriminant analysis of hydrochemical data also shows that the classification of waters into four types are so realistic to adequately reflect the major process(es) proposed for the hydrochemical evolution of each water type. As a tool for evaluating the degree of seawater mixing, we propose a parameter called 'Seawater Mixing Index (S.M.I.)’ which is based on the concentrations of Na, Mg, Cl, and $SO_4$. All the type 1 and 3 waters have the S.M.I. values smaller than one, while type 2 and type 4 waters mostly have the values greater than 1. In the western coastal area of Korea, more than 21% of shallow groundwaters appear to be more or less affected by salinization process.

• 한국수산과학회지
• /
• 제54권4호
• /
• pp.456-466
• /
• 2021

The distribution and abundance of euphausiids were investigated in Korean waters in 2016. Euphausiids were sampled with a Bongo net. A CTD (Sea Bird Electronics 9 plus) measured the water temperature and salinity while sampling. Mean water temperature ranged from 4.2-31.0℃. The highest temperatures occur in September and lowest temperatures in February. The mean water salinity ranged from 27.9-34.8 psu, with the highest salinities in March and lowest in September. Euphausiid species in group W consisted of four species. Among the euphausiid species, Euphausia pacifica was the dominant species with peak densities in September. The E. pacifica from group W was distributed in the bottom cold water during summer when a thermocline was formed. Five euphausiid species occurred in group S. E. pacifica and E. nana were the dominant species. In group S, E. nana was located in the warm and saline Tsushima Warm Current, a branch of the influential Kuroshio Current. Five euphausiid species occurred in group E. E. pacifica and T. longipes were the dominant species. In group E, E. pacifica and T. longipes were distributed in the deep and cold waters, these species prefer low water temperatures and perform vertical migration. The distribution of euphausiids in Korean waters were highly influenced by mass water characteristics, such as temperature and salinity.