• 한국패류학회지
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• 제29권2호
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• pp.147-154
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• 2013

In Incheon bay, mass mortalities of Manila clam associated with winter storms have been reported. In the present study we have monitored pathologic condition of the clams stranded on the tidal flats by the winter storms occurred in late March to early April in 2007. The field surveyed indicated that mortality of the Manila clam in the study areas ranged 10-15%. Condition index, a ratio of tissue weight to the shell weight, of the stranded clams was significantly lower than the non-stranded normal clams collected from the same locations (p < 0.05), indicating that the stranded clams were comparatively in poor physiological condition. Perkinsus olseni, the protozoan parasite was observed most of clams used in the analysis and the infection prevalence ranged 77-90%. The infection intensity of P. olseni determined using Ray's fluid thioglycollate medium (RFTM) cultivation and the 2M NaOH digestion assay indicated that the clams collected during late March and early April in 2007 involved 67,182-1,124,727 P. olseni cells/g tissue. The infection intensity of clams from Gung-Pyeung was significantly higher than the intensities observed from Dae-Bu and Young-Heung (p < 0.05). No clear correlation was found between the infection intensities of P. olseni in the non-stranded normal clams and the stranded clams. The stranded Manila clams were also infected with trematode parasite with the prevalence ranged 5 (Young-Heung) to 12.5% (Dae-Bu). The trematode-infected clams exhibited castrated follicles in the gonad, a typical sign of trematode infection. It was believed that mass mortality of Manila clam observed in this study was associated with the poor physiological condition as indicated by CI, although impacts of the parasite infection cannot be ruled out.

• Ocean and Polar Research
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• 제41권3호
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• pp.121-133
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• 2019

Natural variability associated with a variety of large-scale climate modes causes regional differences in sea level rise (SLR), which is particularly remarkable in the Pacific Ocean. Because the superposition of the natural variability and the background anthropogenic trend in sea level can potentially threaten to inundate low-lying and heavily populated coastal regions, it is important to quantify sea level variability associated with internal climate variability and understand their interaction when projecting future SLR impacts. This study seeks to identify the dominant modes of sea level variability in the tropical Pacific and quantify how these modes contribute to regional sea level changes, particularly on the two strong El $Ni{\tilde{n}}o$ events that occurred in the winter of 1997/1998 and 2015/2016. To do so, an adaptive data analysis approach, Ensemble Empirical Mode Decomposition (EEMD), was undertaken with regard to two datasets of altimetry-based and in situ-based steric sea levels. Using this EEMD analysis, we identified distinct internal modes associated with El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) varying from 1.5 to 7 years and low-frequency variability with a period of ~12 years that were clearly distinct from the secular trend. The ENSO-scale frequencies strongly impact on an east-west dipole of sea levels across the tropical Pacific, while the low-frequency (i.e., decadal) mode is predominant in the North Pacific with a horseshoe shape connecting tropical and extratropical sea levels. Of particular interest is that the low-frequency mode resulted in different responses in regional SLR to ENSO events. The low-frequency mode contributed to a sharp increase (decrease) of sea level in the eastern (western) tropical Pacific in the 2015/2016 El $Ni{\tilde{n}}o$ but made a negative contribution to the sea level signals in the 1997/1998 El $Ni{\tilde{n}}o$. This indicates that the SLR signals of the ENSO can be amplified or depressed at times of transition in the low-frequency mode in the tropical Pacific.

• 식물분류학회지
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• 제39권4호
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• pp.264-276
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• 2009

본 연구는 한반도산 염생식물 분포를 밝히기 위해 해안 염습지와 사구 95지역을 조사하였다. 연구결과 남한의 해안과 섬지역 등에서 21과 44속 57종 4변종 1품종 등 62 염생식물이 기록되었다. 이 중 33분류군은 사구에 자라며, 나머지 29분류군은 염습지에 자라는 식물이다. 61지역이 조사된 서해안에는 58분류군이 분포하였으며, 이들 중 염습지에서는 나문재, 칠면초, 갈대, 갯잔디, 천일사초가, 사구에서는 수송나물, 갯완두, 갯길경, 갯메꽃이 많이 발견되었다. 한편 15지역이 조사된 남해안에는 서해안 보다 적은 45분류군이 분포하였다. 13지역이 조사된 동해안에는 44분류군이 분포하였으며, 흔히 발견된 식물은 수송나물, 갯완두, 갯메꽃으로 모두 사구식물이다. 해란초는 한반도에서는 동해안에서만 조사되었다. 6 지역이 조사된 제주도에는 30분류군이 분포하였다. 해녀콩은 국내에서는 제주도에서만 발견되었다. 한국산 염생식물 중 약 절반은 12종의 명아주과, 12종의 벼과, 7종의 국화과 등 3과에 속하였다.

• 한국지구과학회지
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• 제40권3호
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• pp.240-258
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• 2019

태풍, 집중호우, 대설은 매년 우리나라에서 치명적인 손실을 초래한다. 따라서 정기적인 관측을 통하여 이러한 현상의 발생 가능성을 미리 알 수 있다면, 사회적으로 큰 유익을 제공할 수 있을 것이다. 우리나라는 삼면이 바다로 둘러싸여 있고, 해수면온도가 태풍, 집중호우, 대설 발달에 직 간접적으로 영향을 미치므로, 이 논문에서는 위험기상과 관련하여 나타나는 해수면온도 변동성의 특성을 조사하였다. 우리나라에서 발생하는 집중호우는 서울경기 부근 및 서해안을 중심으로, 그리고 남해안을 중심으로 분포하였다. 대설은 주로 동해안지역(이하 영동 대설)과 남서부 지역(호남형 대설)에서 발생하였다. 위험기상 종류 및 주요 발생지역에 따라 해수면온도 변동성이 조금씩 다르게 나타났으며, 집중호우 발생 시에 진도-제주도-이어도-중국 상하이 방향으로 이어지는 해역에서 해수면온도 변동성이 크게 나타났다. 대설 발생 시, 대설형태와 상관없이, 제주도 남쪽 해상에서 해수면온도 변동성이 작은 영역이 관측되었으며, $130^{\circ}E$, $39^{\circ}N$ 부근 동해상에서 강한 해수면온도 변동성이 나타났다. 해수면온도 변동성이 큰 지역은, 대기-해양 상호작용 메커니즘을 연구하는 기초자료로 사용될 수 있을 뿐만 아니라, 배경대기 에어로졸 관측영역 결정에도 활용될 것이다.

• 한국어류학회지
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• 제28권2호
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• pp.116-120
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• 2016

풀미역치과에 속하는 Cocotropus masudai 1개체 (표준체장 41.2 mm)가 2011년 7월에 제주도 연안에서 상업용 통발에 처음으로 채집되었다. 이 종은 등지느러미 기조수 XII, 9개를 갖는 점, 뒷지느러미 기조수 I, 8개를 갖는 점, 배지느러미 기조수 I, 3개를 갖는 점, 전새개골에 4개의 가시를 갖는 점, 아래턱에 5개의 감각공을 갖는 점 그리고 흉부의 끝이 다섯 번째 감각공을 지나는 특징을 갖는다. 이 종은 형태적으로 C. izuensis와 유사하지만 전새개골의 가시수 (C. izuensis는 5개 vs. C. masudai는 4개를 가짐)와 흉부의 끝의 위치 (C. izuensis는 다섯 번째 감각공을 훨씬 지남 vs. C. masudai 도달함)로 구분할 있다. 그리고 이 종은 우리나라에서 서식하는 풀미역치에 대해 등 지느러미 연조수가 9개 (풀미역치는 10~14개), 뒷지느러미 연조수 7개 (풀미역치는 10~13개) 그리고 배지느러미 연조수는 3개 (풀미역치는 2개)로 구분할 수 있다. 이 미기록종의 속명과 국명은 각각 "돛치속"과 "돛치"로 제안한다.

• Ocean and Polar Research
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• 제40권1호
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• pp.1-13
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• 2018

Previous studies have indicated a great regional difference in Sea Level Rise (SLR) in the Pacific and it has been suggested that this is linked to climate variability over the past two decades. In this study, we seek to identify the possible linkage between regional sea level and Pacific climate variability from altimetry-based sea level data (1993-2012) and further investigate how the Pacific sea level has changed spatially and temporally over the past 60 years from long-term sea level reconstruction data (1953-2008). Based on the same method as Zhang and Church (2012), the Inter-annual Climate Index (ICI) associated with the El $Ni{\tilde{n}}o-Southern$ Oscillation (ENSO) and the Decadal Climate Index (DCI) associated with Pacific Decadal Oscillation (PDO) are defined and then the multiple variable linear regression is used to analyze quantitatively the impact of inter-annual and decadal climate variability on the regional sea levels in the Pacific. During the altimeter period, the ICI that represents ENSO influence on inter-annual time scales strongly impacts in a striking east-west "see-saw mode" on sea levels across the tropical Pacific. On the other hand, the decadal sea level pattern that is linked to the DCI has a broad meridional structure that is roughly symmetric in the equator with its North Pacific expression being similar to the PDO, which largely contributes to a positive SLR trend in the western Pacific and a negative trend in the eastern Pacific over the two most recent decades. Using long-term sea level reconstruction data, we found that the Pacific sea levels have fluctuated in the past over inter-annual and decadal time scales and that strong regional differences are presented. Of particular interest is that the SLR reveals a decadal shift and presents an opposite trend before and after the mid-1980s; i.e., a declining (rising) trend in the western (eastern) Pacific before the mid-1980s, followed by a rising (declining) trend from the mid-1980s onward in the western (eastern) Pacific. This result indicates that the recent SLR patterns revealed from the altimeters have been persistent at least since the mid-1980s.

• 식물분류학회지
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• 제40권4호
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• pp.267-273
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• 2010

본 연구는 표본과 현지조사를 토대로 대표적 난온대성 상록활엽수인 붉가시나무, 참식나무, 후박나무의 한반도 분포를 조사하고, 각 종의 분포도를 작성하였다. 조사결과 이 종들은 제주도, 울릉도, 남해안 및 서해의 인천 도서지방까지 분포하며, 이는 한반도 남해안아구계와 일치하였다. 붉가시나무의 서쪽 자생북한계지는 인천시 옹진군 덕적면 납도이었으며, 동쪽은 금번조사를 통해 울릉도에서 새로운 자생지가 확인되었다. 참식나무의 자생북한계지는 인천시 옹진군 덕적군도(각흘도, 광대도, 하고도)이었으며, 후박나무의 자생북한계지는 인천시 옹진군 대청도로, 3종중 가장 고위도 까지 분포하였다. 이들 상록활엽수 분포 조사결과는 한반도 식물구계 구분 및 기후변화 생물지표자료로 활용할 수 있을 것이다.

• 한국수산과학회지
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• 제56권4호
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• pp.428-437
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• 2023

A simultaneous analytical method was developed and validated for the analysis of prohibited fluoroquinolone (FQ) antibiotics including norfloxacin, ofloxacin, and pefloxacin, released by aquaculture in seawater and effluents. The samples were filtered, and extracts were obtained using a solid phase extraction cartridge with methanol (MeOH). The extracts were concentrated, and analyzed using ultra-performance liquid chromatography-tandem mass spectrometry. Two different columns and four different mobile phases were compared to achieve optimal separation and sensitivity for target compounds. Typical validation parameters including linearity, recovery of surrogate standard, instrument detection limit (IDL), limit of quantification (LOQ), and method detection limit (MDL) were evaluated. The linearity of calibration curves was over 0.999. Recoveries of surrogate ranged from 87.6% to 113%. The LOQ of target compounds was approximately 3-8 times lower than those reported in previous studies. The IDL and MDL were 0.06-0.57 and 0.06-0.37 ng/L, respectively. Seven effluent samples collected from an aquaculture located in Jeju were analyzed; however, not all target compounds were detected in the samples, suggesting that the banned antibiotics were not used. Overall, this established method was able to simultaneously analyze the three FQ antibiotics, and may be useful for monitoring prohibited antibiotics in the fishery industry.

• 수산해양기술연구
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• 제56권1호
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• pp.26-36
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• 2020

Thousands of pelagic and demersal fishes inhabit the waters around Korea and many of them are overexploited. One of the reasons is technological development, which increases the efficiency of the vessels continuously. The analysis was conducted to identify the change of fishing power index to develop the vessel and gear technology that may have improved the fishing efficiency of the otter trawl fishery from 1960s to 2010s. Gross tonnage was decreased stably, but horse power was increased annually. The perimeter of net mouth was somewhat longer, but little changed. Color fish finder was utilized from the mid-1960s. Hydraulic net drum were introduced in the early 1990s, and supply rate was gradually increased. Surveys on the supply and upgrading of fishing equipment utilized visiting research. Therefore, the relative fishing power index in the trawl fishery increased about two to three times in the 2010s compared to the 1980s. The results are expected to contribute to reasonable fisheries stock management.

• 한국군사과학기술학회지
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• 제18권4호
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• pp.469-477
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• 2015

In this study, the characteristics of main wind direction, vertical temperature and wind speed profile near the Moseulpo airfield for HALE UAV(High Altitude Long Endurance Unmaned Aerial Vehicle) is investigated. The results are summarized as follows, main wind direction is governed by air mass according to season and local wind such as land-sea breeze. The directions of landing and take-off of HALE UAV will be selected as the south-east direction in June ~ August, north-west direction in October ~ March, and south-east direction at daytime in April ~ May, September. Annual variation of temperature at 100 hPa showed that temperature in summer season is lower than winter season. On the other hands, wind speed at 250 hPa in winter season is higher than summer season. The threshold values of temperature and wind speed for HALE UAV flight are $-75^{\circ}C$ and $90ms^{-1}$, which were determined by 5 % frequency value($1.96{\sigma}$), respectively.