• Ocean and Polar Research
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• 제26권1호
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• pp.65-75
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• 2004

In order to understand the water masses and their distribution in the eastern Yellow Sea from winter to spring, a cluster analysis was applied to the temperature and salinity data of Korea Oceanographic Data Center from 1970 to 1990. From December to April, Yellow Sea Cold Water (YSCW) dominates the eastern Yellow Sea, whereas Eastern Yellow Sea Mixed Water (MW) and Yellow Sea Warm Water (YSWW) are found in the southern part of the eastern Yellow Sea. MW appears at the frontal region around $34^{\circ}N$ between YSCW in the north and YSWW in the south. On the other hand, Tshushima Warm Water (TWW) is found around Jeju Island and the South Sea of Korea. These water masses are relatively well-mixed throughout the water column due to the winter monsoon. However, the water column begins to be stratified in spring due to increased solar heating, the diminishing winds and fresh water discharge, and the water masses in June may be separated into surface, intermediate and bottom layers of the water column. YSWW advances northwestward from December to February and retreats southeastward from February to April. This suggests a periodic movement of water masses in the southern part of the eastern Yellow Sea from winter to spring. YSWW may continue to move eastward with the prevailing eastward current to the South Sea from April to June. Also, the front relaxes in June, but the mixed water advances to the north, increasing salinity. The salinity is also higher in the nearshore region than offshore. This indicates an influx of oceanic water to the north in the nearshore region of the eastern Yellow Sea in spring in the form of mixed water.

• 한국해양학회지:바다
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• 제18권4호
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• pp.163-177
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• 2013

동해 남서부에 위치한 강릉-울릉도간 해역에서 정기여객선 씨스타호에 수온, 염분 및 클로로필a 형광센서를 설치하고 2012년 7월부터 2013년9월까지 북한한류와 동한난류역을 가로질러 매일 왕복조사를 수행하여 해수물성을 연속관측 하였다. 본 연구에서는 염분과 클로로필a 형광 기록과 동해정선관측 및 환경측정망조사 결과, AVISO의 일별 표면해류도 그리고 GOCI 클로로필a 영상을 이용하여 표층해역의 염분 시계열 변동을 분석하였다. 본 연구 결과, 6월부터 10월까지 강릉-울릉도간 표층 해역에 염분범위 33.15~34.12의 고염분수역이 주로 환류의 중간해역이나 강한 북향류의 서쪽 경계역에서 나타났다. 이 수역의 서쪽에는 최저 염분범위가 30.58~33.20로 남향류를 수반하였고 동쪽은 31.30~33.24로 북향류가 수반되었다. 서쪽의 저염분수는 남하하는 북한한류수의 표층수이며, 동쪽의 저염분수는 북상하는 대마난류 표층수이다. 본 연구에서 확인된 북한한류수의 최저염분은 30.36이었으며, 서쪽 저염분수의 동쪽 한계는 강릉 동쪽 약 110 km지점까지, 남쪽으로는 죽변 연안까지 수심 약 5~10 m 이천에서 33.00이하로 분포하였다. 이 저염분수는 하계에 양자강희석수의 혼합으로 저염화된 대마난류 표층수가 북상하면서 수송하는 담수의 규모에 비하여 무시할 수 없을 정도이다. 이것을 본 연구에서는 북한한류수 기원 하계 표층수라고 명명하고자 한다.

• 한국해양학회지:바다
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• 제6권2호
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• pp.49-62
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• 2001

Cochlodinium polykrikoides 유해성적조 발생지역인 한국 남해 나로도와 소리도 사이 해역의 물리적인 환경을 연구하기 위하여 1998년 5월31일부터 9월 24일까지 7회에 걸쳐 수온 및 염분을 관측하였다. 연구해역의 표층에서 30m깊이까지의 수층에서는 관측 초기인 춘계부터 하계로 갈수록 수온이 증가하고 염분은 낮아지는 물성의 계절적인 변화가 뚜렷하였는데 수층전체의 평균수온은 총 조사기간동안 $6^{\circ}C$ 증가하고 평균염분은 2.71 psu 낮아졌다. 관측된 평균염분의 변화는 연구해역의 강수와 인접육지에 의해 공급될 수 있는 담수량만으로는 설명할 수 없었으며, 남해외해역으로부터 유입되는 저염수에 의해 일어났을 것으로 해석되었다. 이 해역에서 적조의 발생시기, 진행시기 및 적조가 사라진 시기에 염분의 공간적인 분포가 다른 특징을 보였으며, 특히 적조가 사라진 시기에는 염분이 직전 시기에 비해 크게 낮아지고 수층구조도 직전시기의 성층구조에서 혼합층구조로 변화하였는데, 이와 같은 변화는 남해 외해역으로부터 저염수의 유입으로만 설명할 수 있었다. 이로부터 물리적인 해수유동이 이 해역에서 적조가사라진 주요한 원인의 하나로 제시되었다. 본 연구결과는 차후 남해 연안역의 적조현상을 이해하기 위해서는 인접 육지로부터 유입되는 환경적 요소들은 물론 대상해역을 포함한 남해 외해역의 해수순환특성, 그리고 해수순환에 의해 이송되는 해수의 물리, 화학 및 생물학적 요소를 종합적으로 연구해야할 필요성을 시사한다.

• Journal of the korean society of oceanography
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• 제33권1-2호
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• pp.1-7
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• 1998

In the western Weddell Sea, winter mixed layer is characterized by near-freezing temperature and higher salinity due to brine injection through sea-ice formation. This layer becomes Winter Water being capped by warmer and less saline Antarctic Surface Water during the sea-ice melt-ing season. In this study, Winter Water was preliminarily identified by the oxygen isotopic com-positions. The ${\delta}^{18}$O values of Winter Water show the progressively increasing trend from south to north in the study area. It presumably reflects the enhanced mixing with Antarctic Surface Water due to the extent of influence by low S'"0 value of sea-ice/glacier meltwater. Correlations between salinity and 6'"0 values of seawater can be used to more generally characterize Winter Water with a view to identification. However, the prediction on the degree of mixing from these relationships needs more detailed isotope data, although this study allows the oxygen isotopic composition of seawater as a tracer to identify the water mass.

• ALGAE
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• 제32권3호
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• pp.223-233
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• 2017

Kelp forests and the many vital ecosystem services they provide are threatened as the severity of climate change and other anthropogenic stressors continues to mount. Particularly in the North Pacific, sea surface temperature is warming and glacial melt is decreasing salinity. This study explored the resiliency of early life-history stages of these foundation species through a factorial laboratory experiment. The effects of rising sea surface temperature under low salinity conditions on kelp spore settlement and initial gametophyte growth in Eualaria fistulosa, Nereocystis luetkeana, and Saccharina latissima were investigated. Decreased settlement and growth were observed in these species at elevated temperatures and at low salinity. Eualaria fistulosa spores and gametophytes were the most negatively impacted, compared to the more widely distributed N. luetkeana and S. latissima. These results suggest that N. luetkeana and S. latissima could potentially outperform E. fistulosa under projected conditions. However, despite decreased performance among all species, our findings indicate that these species are largely resilient to temperature changes when exposed to a low salinity, even when the temperature changes are immediate and extreme. By exploring how early life-history stages of several key kelp species are impacted by dual stressors, this research enhances our understanding of how kelp forests will respond to projected and extreme changes in temperature when already stressed by low salinity.

• 한국환경보건학회지
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• 제44권3호
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• pp.259-266
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• 2018

Objectives: Considered the "national fish" in Korea, the walleye pollock (Gadus chalcogrammus) has disappeared in the East Sea (Sea of Japan), a main habitat and fishing ground for the species. The reason for the disappearance is still a matter of controversy. This study was performed to investigate the long-term relationship between the walleye pollock catch and various meteorological and oceanographic factors in these waters. Methods: Fishery data on walleye pollock and data on meteorological and marine environmental factors over the 30 years (1981-2010) were obtained from the official national database. Time series analysis and correlation and regression analyses were performed to study the relationships. Results: Both air temperature and sea surface temperature in the East Sea rose over these 30 years, and the latter became more prominent. Salinity and dissolved oxygen showed a tendency to decrease while concentrations of nutrients such as nitrite nitrogen and nitrate nitrogen showed an increasing tendency. Sea surface temperature, air temperature, atmospheric pressure, and wind grade were negatively correlated with the catch size of walleye pollock (p<0.05), but salinity was positively correlated (p<0.001). Conclusion: The results of this study indicate that climate change, especially ocean warming, affected the habitat of walleye pollock. The results also indicate that lower sea surface and air temperatures, milder wind grade, and higher salinity were preferred for the survival of the fish species. It is necessary to pay attention to changes of the ocean ecosystem in terms of environmental pollution as well as seawater temperature.

• 한국해양학회지:바다
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• 제3권3호
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• pp.165-169
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• 1998

1996년 8월 1일부터 10일까지 남해 해양조사에서 얻어진 자료를 이용하여 우리나라 남해 표층의 저염화현상과 표층수 중 영양염류의 분포특성에 대해 고찰하였다. 제주도 서쪽에 위치한 313선의 05점과 제주도 남쪽에 위치한 314선의 09점에서 20.00 psu 이하의 저염수가 출현하고 있으며, 이 저염수의 핵을 중심으로 30.00 psu 이하의 저염수가 남해 동부해역을 제외한 제주도 주변 대부분의 해역들에 나타나고 있다. 이러한 저염수의 최저염분 농도는 과거 30년 동안의 평균값보다 11.78 psu 낮은 값으로서 이는 양자강 유역에서 6월과 7월에 평년보다 훨씬 많은 강수량에 의해 막대한 양의 담수가 유출되었기 때문이라고 생각된다. 또한, 이러한 저염수는 대체적으로 수심 10~20 m 상부층에 존재하고 있어서 중 저층수와는 확실히 구분되고 있다. 표층수 중 영양염류는 인산인의 경우 농도가 비교적 낮고, 해역별 차이도 매우 작았다. 그러나, 질산질소와 규산규소는 저염수가 분포하고 있는 제주도 서쪽 및 남서쪽 해역에서 비교적 높은 농도를 보이며, 특히 염분농도가 가장 낮은 정점에서 농도가 가장 높았다. 질산질소와 규산규소의 경우 보존성 성분인 염분과 역의 상관성을 보이는데, 이는 양자강 유출수와 같이 영양염류 농도가 풍부한 물이 제주도 서쪽 해역으로 이동되어 왔음을 의미한다. 그라나, 인산인이 다른 영양염류 성분과는 달리 염분의 큰 변동에도 불구하고 농도 변화가 거의 일정한 것은 해수중의 물질순환과정이 질산질소 및 규산규소와는 다름을 의미한다.

• Fisheries and Aquatic Sciences
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• 제3권2호
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• pp.143-150
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• 2000

Assuming that summer surface waters in the South Sea (northern East China Sea) are formed mostly by a mixing of three source water (Changjiang Discharge Water; Kuroshio Water and Yellow Sea Surface Water) we apply optimum multiparameter (OMP) analysis to calculate the mixing ratio of each source water to a given surface water. Since OMP requires more parameters than the number of water types (three in this study), we utilize two radium isotopes of dissolved $^{226}Ra\;and\;^{228}Ra$ along with temperature and salinity. Parameter values of each source water are deduced from in situ and historical data. Results with three source of waters on the surface waters are quite promising with less than $1\%$ of unanswered portions. Results not only reproduce the measured temperature and salinity faithfully but also discern the water masses of similar T and S according to their source water mixing. Extending OMP analysis to a whole water column obviously requires more parameters because more source waters are involved in the water mass formation. Original OMP routine utilized dissolved oxygen and nutrients. However, they seem to be perturbed too much by biological activities in the case of shallow waters. We discussed the use of other potential parameters. Also the benefit of parameter substitution is briefly introduced for the future OMP application on shallow waters.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.481-484
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• 2006

This research compares oyster farming in Gamak Bay which Hiroshima Bay which has nearly similar marine environments. The marine environment of these two waters has similar variations of air temperature, sea surface temperature, precipitation and salinity. However Hiroshima Bay is higher than Gamak Bay in the sea surface temperature and Hiroshima Bay is also higher than Gamak Bay in the salinity. Their oyster farming method is basically similar but it is different in their facilities. We need to take some measures against high mortalities, and in addition, to enhance the rate of seed collection.

• Ocean and Polar Research
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• 제27권3호
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• pp.277-288
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• 2005

Spatial distribution and vertical structures of water masses around the Antarctic continental margin are described using synthesized hydrographic data. Antarctic Surface Water (AASW) over the shelf regime is distinguished from underlying other water masses by the cut-off salinity, varying from approximately 34.35 to 34.45 around Antarctica. Shelf water, characterized by salinity greater than the cut-off salinity and potential temperature less than $-17^{\circ}C$, is observed on the Ross Sea, off George V Land, off Wilkes Land, the Amery Basin, and the Weddell Sea, but in some shelves AASW occupies the entire shelf. Lower Circumpolar Deep Water is present everywhere around the Antarctic oceanic regime and in some places it mixes with Shelf Water, producing Antarctic Slope Front Water (ASFW). ASFW, characterized by potential temperature less than about $0^{\circ}C$ and greater than $-17^{\circ}C$, and salinity greater than the cut-off salinity, is found everywhere around Antarctica except in the Bellingshausen-Amundsen sector. The presence of different water masses over the Antarctic shelves and shelf edges produces mainly three types of water mass stratifications: no significant meridional property gradient in the Bellingshausen and Amundsen Seas, single property gradient where ASFW presents, and a V-shaped front where Shelf Water exists.