• 제목/요약/키워드: Northwest Pacific waters

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First Finding of the Mud Shrimp Upogebia yokoyai Makarov, 1938 (Crustacea: Decapoda: Upogebiidae) in Korean Waters

  • Hong, Jae-Sang;Lee, Chae-Lin
    • Ocean and Polar Research
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    • 제36권3호
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    • pp.235-246
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    • 2014
  • The thalassinidean upogebiid Upogebia yokoyai Makarov, 1938 was first collected and described based on the specimens from the upper tidal flat of sandy shores of Jeju Island, Korea. Although this species was already reported in Japan and Russia, this is the first report of its occurrence in Korea. Upogebia yokoyai differs clearly from other upogebiid species previously recorded in Korean waters, U. major and U. issaeffi, by spinulation of the dactylus and propodus of pereiopod 1. In addition, some morphological comparisons are provided for identification of the three Upogebia species in Korean waters.

북서태평양에서 종속영양 원생생물 군집 및 섭식압의 해역별 비교 (Regional Comparisons of Heterotrophic Protists Grazing Impacts and Community in Northwest Pacific Ocean)

  • 양은진;주세종;김웅서
    • Ocean and Polar Research
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    • 제30권3호
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    • pp.289-301
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    • 2008
  • Community structure of heterotrophic protists and their grazing impact on phytoplankton were studied in Northwest Pacific Ocean during October, 2007. The study area was divided into four regions based on physical properties (temperature and salinity) and chlorophyll-a distribution. They were Region I of North Equatorial Currents, Region II of Kuroshio waters, Region III of shelf mixed water, and Region IV of Tsushima warm current from East China Sea. The distribution of chlorophyll-a concentrations and community structure of heterotrophic protists were significantly affected by physical properties of the water column. The lowest concentration of chlorophyll-a was identified in Region I and II, where pico-sized chlorophyll-a was most dominant (>80% of total chlorophyll-a). Biomass of heterotrophic protists was also low in Region I and II. However, Region III was characterized by low salinity and temperature and high chlorophyll-a concentration, with relatively lower pico-sized chlorophyll-a dominance. The Highest biomass of heterotrophic protists appeared in Region III, along with the relatively less important nanoprotists. In Region I, II and IV, heterotrophic dinoflagellates were dominant among the protists, while ciliates were dominant in Region III. Community structure varied with physical(salinity and temperature) and biological (chlorophyll-a) properties. Biomass of heterotrophic protists correlated well with chlorophyll-a concentration in the study area ($r^2=0.66$, p<0.0001). The potential effect of grazing activity on phytoplankton is relatively high in Region I and II. Our result suggest that biomass and size structure of heterotrophic protists might be significantly influenced by phytoplankton size and concentration.

ATMOSPHERIC CORRECTION TECHNIQUE FOR GEOSTATIONARY OCEAN COLOR IMAGER (GOCI) ON COMS

  • Shanmugam, Palanisamy;Ahn, Yu-Hwan
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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    • pp.467-470
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    • 2006
  • Geostationary Ocean Color Imager (GOCI) onboard its Communication Ocean and Meteorological Satellite (COMS) is scheduled for launch in 2008. GOCI includes the eight visible-to-near-infrared (NIR) bands, 0.5km pixel resolution, and a coverage region of 2500 ${\times}$ 2500km centered at 36N and 130E. GOCI has had the scope of its objectives broadened to understand the role of the oceans and ocean productivity in the climate system, biogeochemical variables, geological and biological response to physical dynamics and to detect and monitor toxic algal blooms of notable extension through observations of ocean color. To achieve these mission objectives, it is necessary to develop an atmospheric correction technique which is capable of delivering geophysical products, particularly for highly turbid coastal regions that are often dominated by strongly absorbing aerosols from the adjacent continental/desert areas. In this paper, we present a more realistic and cost-effective atmospheric correction method which takes into account the contribution of NIR radiances and include specialized models for strongly absorbing aerosols. This method was tested extensively on SeaWiFS ocean color imagery acquired over the Northwest Pacific waters. While the standard SeaWiFS atmospheric correction algorithm showed a pronounced overcorrection in the violet/blue or a complete failure in the presence of strongly absorbing aerosols (Asian dust or Yellow dust) over these regions, the new method was able to retrieve the water-leaving radiance and chlorophyll concentrations that were consistent with the in-situ observations. Such comparison demonstrated the efficiency of the new method in terms of removing the effects of highly absorbing aerosols and improving the accuracy of water-leaving radiance and chlorophyll retrievals with SeaWiFS imagery.

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SATELLITE DETECTION OF RED TIDE ALGAL BLOOMS IN TURBID COASTAL WATERS

  • Ahn, Yu-Hwan;Shanmugam, Palanisamy
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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    • pp.471-474
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    • 2006
  • Several planktonic dinoflagellates, including Cochlodinium polykrikoides (p), are known to produce red tides responsible for massive fish kills and serious economic loss in turbid Northwest Pacific (Korean and neighboring) coastal waters during summer and fall seasons. In order to mitigate the impacts of these red tides, it is therefore very essential to detect, monitor and forecast their development and movement using currently available remote sensing technology because traditional ship-based field sampling and analysis are very limited in both space and temporal frequency. Satellite ocean color sensors, such as Sea-viewing Wide Field-of-view Sensor (SeaWiFS), are ideal instruments for detecting and monitoring these blooms because they provide relatively high frequency synoptic information over large areas. Thus, the present study attempts to evaluate the red tide index methods (previously developed by Ahn and Shanmugam et al., 2006) to identify potential areas of red tides from SeaWiFS imagery in Korean and neighboring waters. Findings revealed that the standard spectral ratio algorithms (OC4 and LCA) applied to SeaWiFS imagery yielded large errors in Chl retrievals for coastal areas, besides providing false information about the encountered red tides in the focused waters. On the contrary, the RI coupled with the standard spectral ratios yielded comprehensive information about various ranges of algal blooms, while RCA Chl showing a good agreement with in-situ data led to enhanced understanding of the spatial and temporal variability of the recent red tide occurrences in high scattering and absorbing waters off the Korean and Chinese coasts. The results suggest that the red tide index methods for the early detection of red tides blooms can provide state managers with accurate identification of the extent and location of blooms as a management tool.

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Population Structure of Minke Whales (Balaenoptera acutorostrata) in the Korean Waters Based upon Mitochondrial DNA Polymorphism

  • Park, Jung-Youn;Kim, Mi-Jung;An, Yong-Rock;Kim, Zang-Kun;An, Hye-Suck;Moon, Hyo-Bang;Kim, Kyung-Kil;Sohn, Haw-Sun
    • Animal cells and systems
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    • 제13권4호
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    • pp.419-427
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    • 2009
  • The Minke whale, Balaenoptera acutorostrata, is the smallest baleen whale in the suborder Mysticeti. Because this species inhabits coastal areas, it became a main target species of coastal small-type whaling in the North Atlantic and the Northwest Pacific Oceans, and the species' population size dramatically decreased because of over-exploitation. As a result, the International Whaling Commission declared a global moratorium on whaling and launched the development of a management procedure for protecting the whales. Morphological studies, whaling history analysis, and genetic studies conducted mainly by Japanese scientists showed the existence of one unique "E" stock that inhabits the waters around the Korean peninsula and mixes with the "O" stock in the southern part of the Sea of Okhotsk. We used the mitochondrial DNA control region polymorphism of 348 Minke whales bycaught or stranded in Korean waters from 30 October 1998 to 25 June 2005 to assess the whale population structure by year. The frequency of the 10 major haplotypes from the 40 identified haplotypes was not significantly different among groups, suggesting that a subpopulation was not present. A comparison of the genetic distances calculated with Tamura-Nei's method showed that the distances between groups were lower than those within groups, which suggests that there was no genetic difference in the Minke whale populations. The Fst comparison between groups and the phylogenetic tree constructed using the unweighted pair group method with arithmetic mean (UPGMA) and Neighbor Joining (NJ) method also detected no obvious sub-stock structure.

북서태평양에서의 북태평양중층수 (North Pacific Intermediate Water in the Northwest Pacific)

  • 양성기
    • 한국환경과학회지
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    • 제3권3호
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    • pp.229-239
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    • 1994
  • 북태평양에 위치한 일본근애의 수괴분포에 대한 특성을 중층수에 중점을 두어 일본 해상 기상청이 관측한 정이 해양관측정선에서 얻어진 자료를 사용하여 검토하였다. 쿠로시오해역의 T-S도상에서 분산은 비교적 작게 나타나고 있다. 쿠로시오해역에서 고온, 고염분층에서부터 저온, 저염분측으로 이동하고 있다. 혼합해역에서 수형의 분한은 북으로 이동함에 따라 고염분측의 이동보다 저온, 저염분측으로 급격히 증가하고 있다. 염분극소층에서 해수의 써모스테릭 아노말리(thermosteric anomaly)는 해양관측정선이 북에서 남으로 이동함에 따라 감소하고 있다. 이러한 사실은 해수가 염분극소층을 따라 남하하는 것이 아니고, 염분극소층이 두 해수의 수직적인 경계임을 제시하고 있다. 여기서 오야시오수와 쿠로시오수의 두 전형적인 수괴를 정의하고 있따. 염분극소층보다 깊은 부분의 T-S도는 전형적인 오야시오수와 쿠로시오수가 같은 양으로 혼합하는데 대해, 염분극소층보다 상층에서는 전혀 다름 양상을 나타내고 있다. 염분극소층 해수의 써모스테릭 아노말리가 북에서 남으로 이동함에 따라 뚜렷이 감소해 간다. 이러한 사실은 왜 염분극소층에서 써모스테릭 아니말리의 값이 북에서 남쪽으로 이동함에 따라 감소하는지를 설명해 주고 있다.

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북서태평양에서 난수성(Pleuromamma sp.)과 냉수성(Neocalanus plumchrus) 요각류의 지방 함량 및 구성 분석을 통한 생리/생태 비교 (The Physiological and Ecological Comparisons between Warm (Pleuromamma sp.) and Cold Water Copepod Species (Neocalanus plumchrus) in the Northwestern Pacific Ocean Using Lipid Contents and Compositions)

  • 고아라;주세종;이창래
    • Ocean and Polar Research
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    • 제31권1호
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    • pp.121-131
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    • 2009
  • In an effort to better understand the physiological and ecological differences between warm and cold water copepod species in Korean waters using lipid contents and compositions, two species of copepods (Pleuromamma sp. as a warm water species and Neocalanus plumchrus as a cold water species) were collected from the Northwest Pacific and East Sea/Sea of Japan, respectively. The cold water species showed two fold higher lipid contents than the warm water species (11% vs. 5% of dry weight). Wax esters, known as one of the major storage lipid classes, were found to be the dominant lipid class (accounting for 64% of total lipids) in the cold water species, whereas, in the warm water species, phospholipids, which are known as membrane components, were the dominant lipid class (accounting for 43% of total lipids),with a trace amount of the storage lipids as a form of triacylglycerols (${\leq}1%$ of total lipids). With regard to the fatty acid compositions, saturated fatty acids (SAFA), especially 16:0 (about 30% of total fatty acids), were most abundant in the warm water species, whereas the polyunsaturated fatty acids (PUFA), particularly eicosapentaenoic acid (EPA : 20:5(n-3)) (${\geq}16%$ of total fatty acids), were most abundant in the cold water species. Among the neutral fraction of lipids, phytol, originating from the side chain of chlorophyll and indicative of active feeding on phytoplankton, was detected only in the warm water species. Significant quantities of fatty alcohols were detected in cold water species, particularly long-chain monounsaturated fatty alcohols (i.e. 20:1(n-9) and 22:1(n-11)), which are well known to abound in cold water herbivorous copepods. However, only trace amounts of short-chain fatty alcohols were detected in the warm water species. Twelve different kinds of sterols were detected in these copepod species, with cholest-5-en-$3{\beta}$-ol (cholesterol) and cholesta-5, 24-dien-$3{\beta}$-ol (desmosterol) dominating in cold and warm water species, respectively. In addition, for the warm water species (Pleuromamma sp.), we assessed the latitudinal gradients of lipid contents and compositions using samples from three different latitudinal regions (Philippine EEZ, Japan EEZ, and the East China Sea). Although no latitudinal gradients of lipid contents were detected, the lipid compositions, particularly dietary fatty acid markers, varied significantly with the latitude. The findings of this study confirm that the distribution of lipid contents and compositions in copepods may not only indicate their nutritional condition and diet history, but may also provide insights into their living strategies under different environmental conditions (i.e., water temperature, food availability).

Morphological and genetic variability among Ecklonia cava (Laminariales, Phaeophyceae) populations in Korea

  • Choi, Dong Mun;Ko, Young Wook;Kang, Rae-Seon;Kim, Jeong Ha
    • ALGAE
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    • 제30권2호
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    • pp.89-101
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    • 2015
  • Ecklonia cava Kjellman is a common kelp found in shallow subtidal in warm-temperate waters in the northwest Pacific Ocean. This species has shown substantial morphological variation along with subsistence in different locations and local environments. We quantified the magnitude of morphological variation of E. cava from six populations along ~700 km of coastline from Jeju Island to Dokdo in Korea. In addition, we examined genetic distance among the populations using random amplified polymorphic DNA (RAPD) analysis. Most morphological characteristics investigated were significantly different among locations. Multivariate analyses indicated two phenetically distinct groups (nearshore, sheltered vs. offshore, exposed), indicating wave exposure with turbidity are presumably major factors for the separation. With RAPD data, results of Nei's diversity (H) and AMOVA showed considerable variations in within- and between-populations. Pairwise ${\Phi}_{ST}$ and $N_m$ values indicated moderate gene flow between the six locations. Results of Nei's analysis revealed three genetically distinct groups, not consistent with the morphological groupings, indicating that a time gap may exist between morphological and genetic variations. This study also suggests dispersal distance of this kelp may be longer than what is commonly thought and genetic similarity in the populations was largely reflected by the direction of ocean current rather than just geographical distance.

Influences of Climate Factors and Water Temperature in Squid Spawning Grounds on Japanese Common Squid (Todarodes pacificus) Catches in the East (Japan) Sea

  • Lee, Chung-Il
    • Fisheries and Aquatic Sciences
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    • 제10권3호
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    • pp.150-158
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    • 2007
  • Data on squid catches, water temperature, and climatic factors collected for the Northwest and subtropical North Pacific were analyzed to examine the influence of oceanic and climatic conditions in spawning grounds on catches of Japanese common squid, Todarodes pacificus, in the East (Japan) Sea. The main spawning ground was divided into four sub-areas: the South Sea of Korea (R1), the southern waters off Jeju, Korea (R2), the southwestern part of Kyushu, Japan (R3), and the northern part of Okinawa, Japan (R4). Interannual and decadal fluctuations in water temperatures correlated well with squid catches in the East/Japan Sea. In particular, water temperatures at a depth of 50 to 100 m in sub-areas R3 and R4 showed higher correlation coefficients (0.54 to 0.59, p<0.01) in relation to squid catches in the East/Japan Sea than for R1 and R2, which had correlation coefficients of 0.40 or less (p>0.05). Air temperature and wind velocity fluctuations in each sub-area are correlated with water temperature fluctuations and were closely connected with variations in the surface mixed layers. Water, air temperatures and wind velocities at the main spawning grounds are linked to the Southern Oscillation Index (SOI) with higher signals in the ca. 2-4-year band. Strong changes in a specific band and phase occurred around 1976/77 and 1986/87, coincident with changes in squid catches.

동아시아 몬순 지역에서 IODM과 ENSO의 영향 : NCAR Community Atmospheric Model을 이용한 모의 실험 (Impact of IODM and ENSO on the East Asian Monsoon: Simulations through NCAR Community Atmospheric Model)

  • 오재호
    • 한국농림기상학회지
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    • 제7권4호
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    • pp.240-249
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    • 2005
  • 일반적으로 인도양 동쪽 해수면 온도는 따뜻하고, 서쪽 해수면 온도는 차갑다. 이러한 인도양 동/서쪽의 해수면 온도 변화는 인도 해양 다이폴 현상(Indian Ocean Dipole Mode, IODM)이 그 원인이다. 다이폴의 양의 위상은 서쪽 인도양에 양의 SST 아노말 리가 나타나고, 남동 인도양에는 음의 SST 아노말리가 나타나고 음의 위상은 이와 반대의 SST 아노말리가 나타난다. 반면 태평양의 경우, 일반적으로 서쪽 해수면 온도는 따뜻하고, 동쪽 해수면 온도는 차갑다. 중앙/동(서) 태평양 해양의 양(음)의 SST 아노말리가 현상이 나타날 때는 엘니뇨 시기이다. 이와 반대의 SST 아노말리 현상은 라니냐 시기이다 이러한 태평양의 대기-해양간의 상호작용으로 나타나는 현상을 엘니뇨 난방진동(El Nino Southern Oscillation, ENSO)이라 한다. 본 연구에서는 IODM과 ENSO현상에 따른 동아시아 몬순 변동성을 분석하기 위해 관측자료와 NCAR MCA모델 자료를 사용하였다 IODM과 ENSO 현상과 관련된 SST 아노말리 5가지 실험을 수행하였다. IDO모드는 최고의 값이 나타난 이후 약 $3\~4$계절의 시간 지연을 가지고 동아시아의 여름 몬순 활동에 영향을 주는 반면, ENSO는 동아시아 여름 몬순과 같은 계절에 영향을 준다. IODM 음(양의)위상과 태평양에서의 엘니뇨(라니냐) 현상은 한국과 일본지역에서 몬순 활동을 강화(억제)하는 역할을 한다. 반면 중국 지역에서는 IDOM과 몬순 변동성과는 별다른 연관성이 없는 것으로 나타났다. 그러나 엘니뇨(라니냐)일 때, 중국 지역에서 몬순 활동은 억제(강화)되는 경향을 보였다. IODM은 북태평양 아열대 고기압이 강화 할 때 나타나고, ENSO는 북서 태평양 알류산 저기압의 영향으로 나타난다. 따라서 태평양으로부터 동아시아 쪽으로의 수분 공급은 아열대 고기압과 알류산 저기압의 강화/약화에 의해 결정된다.