• 한국석유지질학회:학술대회논문집
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• autumn
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• pp.9-9
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• 2000

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.26-30
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• 2009

본 연구는 고해상도 위성영상을 이용하여 열대해역에서의 생태환경 분포도를 작성함으로써 생태 환경의 변화를 효과적으로 모니터링 할 수 있도록 하는 데에 목적이 있다. 지구온난화 현상에 따라 산호 면적이 감소하고 있다. 이처럼 산호는 환경 변화가 민감하게 반응을 하기 때문에 열대해역에서 산호를 모니터링 하는 것은 주변 생태환경 변화 전체에 대한 관리 역할을 하기 때문에 중요하다. 본 연구에서는 이러한 열대해역의 환경을 효과적으로 모니터링 하기위하여 고해상도 위성영상인 IKONOS와 Kompsat-2 영상을 이용하여 생태환경 분포도를 작성하여보았다. 연구지역은 한남태평양연구센터가 위치한 마이크로네시아 연방국의 Weno 섬 북동쪽 연안이고, 이 지역에서 2007년과 2008년 2번의 현장관측을 실시하여 총 121개 정점에서 광관측 및 환경 자료를 얻었다. 기존의 감독분류와 무감독분류 방법, 그리고 객체지향 영상분류 방법 등을 이용하여 분포도를 작성하였고, 현장관측 자료를 이용하여 검증하였다. 고해상도 영상이기 때문에 기존 방법에서 나타나는 오분류 현상이 객차지향 영상분류 방법을 사용할 경우 적어지는 결과를 얻을 수 있었다.

• Proceedings of the Korean Quaternary Association Conference
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• 2007.06a
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• pp.16-16
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• 2007

• The Korean Journal of Quaternary Research
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• v.13 no.1
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• pp.91-98
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• 1999

The effect of the relative abundances of planktonic foraminifera juveniles on the climatic and oceanographic history interpretations is documented for the first time (as far as we know) by use of the year-long time-series sediment trap samples. Statistical correlation analysis suggests that many climatic and oceanographic variables such as sinking flux (total number) of planktonic foraminifera, relative abundance of some climatic indicator species G. bulloides and N. dutertrei, temperature, and salinity do not show any significant correlations with the relative abundance of planktonic foraminifera juveniles. However, planktonic foraminifera juveniles show moderate correlations with species diversity indices (species richness, Shannon-Wiener index, and Equitability). These indicate that the juveniles do not affect the relative abundances(%) of species compositions but affect the species diversity indices. Based on this one-year trap result, special care is required when we use species diversity indices for the interpretations of paleoceanography when the juveniles are excluded from total planktonic foraminiferal countings.

• 한국해양학회지
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• v.30 no.5
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• pp.493-511
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• 1995

Analysis of the Late Quaternary benthic foraminifera in the cores from the western part of the East Sea, Korea, indicates several distinct changes in the paleoenvironments during the deposition. The palecology of biofacies of Cores PC-1 from the upper slop and PC-2 from the rise shows several distinct changes in bottom water temperatures during the late Quaternary. The Core PC-4 from the Ulleung Basin generally consists of agglutinated genus, Muiliammina, and anaerobic calcareous genus, Bolivina, in biofacies, suggesting that the anoxic bottom condition was prevailed during the deposition. Benthic foraminiferal rare or barren zones in the Cores indicate the limits of water circulation caused by lower sea-level in the regions during the glacial period through the Late Quaternary. The changes of benthic foraminiferal biofacies reflect temporal and spacial variations in overall bottom environments, such as bottom water temperature, dissolved oxygen, and water circulation pattern. The benthic foraminiferal data can be used to interpret paleoclimatic conditions and predict global sea-level changes, and the results of these studies should be useful to understand the evolutional history of the East Sea through the Late Quaternary.

• Ocean and Polar Research
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• v.21 no.2
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• pp.127-136
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• 1999

Radiolarian assemblages from KODOS area were analyzed in order to understand the biostratigraphy and paleoceanography of deep-sea sediment from the Northeast Equatorial Pacific. The sediment core was divided into two or three units on the basis of the chemical and physical properties. In the upper sediment, mixtures of Quaternary and Tertiary radiolarians are found indicating active reworking processes. Dissolution of radiolarians seem to increase with depth. Radiolarians are seldom in Unit III presumably due to dissolution and corrosion. The middle part of unit I appears to correspond to Collosphaera invaginata Zone (0.21 Ma). Unit II belongs to Collosphaera tuberosa Zone. Based on the absence of Stylatractus universus, we estimate its age to be younger than 0.42 Ma. Based on our analyses of radiolarians in Unit I and II, we estimated the age of unit III as Tertiary, particularly from Oligocene to Miocene. There may to be hiatuses of more than 3 My from late Miocene to Pliocene, which probably resulted from erosion and dissolution by the Antarctic Bottom Water Sedimentation rates during Quaternary range from 0.15 to 0.50 mm/ky with significant variabilities among stations. Radiolarians in the study area were mostly warm-water species.

• The Korean Journal of Quaternary Research
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• v.23 no.2
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• pp.48-55
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• 2009

To investigate the paleoceanographic environmental changes around the Okinawa Trough, Japan, a piston core (RN88-PC5) was conducted on benthic foraminiferal species composition, assemblage, sedimentological and geochemical analyses. Trubidite sediment intercalated in studied core contains different benthic foraminiferal species, dwelling in shallow coral reef species, from normal hemipelagic sediment. These different benthic foraminiferal species and its assemblage are interpreted as reworked sediment when turbidite current occurred, synchronically. Grain size analysis clearly showed that mean grain size difference occurred between trubidite and hemipelagic sediments. Geochemical analysis also showed the difference of chemical composition between two sedimentary facies. Results of the foraminiferal oxygen isotope analysis showing global surface water warming records since the last 10 ka. The geochemcial analysis and previous works showed that turbidite sediment of studied core indicating sporadic occurrence of regional paleoceanographic events. Assemblage of shallow coral reef benthic foraminifera especially occurred with turbidite layer clearly support the sporadic occurrence of paleoceanographic events such as regional earthquake.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.707-716
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• 2005

Organic geochemical analyses including Rock-Eval pyrolysis, elemental analysis and stable carbon isotope analysis were performed to evaluate the characteristics of organic matter in the ODP Leg 127 Site 794A sediments and to understand paleoceanographic changes. Based on the TOC contents, C/N ratio, HI vs. OI, $\delta^{13}C_{org}$ and C/S ratio, results imply that dark layers containing a large amount of terrigenous organic matter were deposited under the suboxic/anoxic conditions, whereas the light layers containing largely marine organic matter were deposited under the oxic conditions. These results indicate that increasing surface-productivity by the input of a large amount of terrigenous organic matter from adjacent continent led to the deposition of dark layers during the interglacial highstands, whereas marine primary production and dilution caused by Kosa from the China desert area led to the deposition of light layers with the decreased to terrigenous organic matter during the glacial lowstands.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.4
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• pp.19-26
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• 2002

This is a brief report on the development of a system which provides fishing vessels with a real-time key information that can direct to regions of high fish density. Water temperature and Plankton distribution are the base parameters and various public information have been examined and summarized. The suface water temperature can be obtained from NOAA's high resolution infrared data base and the vertical water temperature can be obtained from TAO/TRITON's buoy near the equator and ARGOS's drifting buoy covering wider Pacific ocean. MODIS's data is also utilized for sea color information. A model data format is proposed and a few examples are demonstrated.

• Economic and Environmental Geology
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• v.56 no.1
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• pp.55-63
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• 2023

Variations in geochemical and mineralogical properties of the ferromanganese(Fe-Mn) crust reflect environmental changes. In the present study, geochemical and mineralogical analyses, including micro X-ray fluorescence and X-ray diffraction, were utilized to reconstruct the paleo-ocean environment of western Pacific Magellan seamount cluster. Samples of the Fe-Mn crust were collected using an epibenthic sledge from the open seamount XX (151° 51.12' 7.2" E and 16° 8.16' 9.6" N, 1557 meters below sea level) in the Western Pacific Magellan Seamount. According to the structure and phosphating status, the Fe-Mn crust of the OSM-XX can be divided into the following: phosphatizated (L4-L5), massive non-phosphatizated (L3), and porous non-phosphatizated (L1-L2) portions. All ferromanganese layers contain vernadite, and owing to the presence of carbonate fluorapatite (CFA), the phosphatizated portion (L4-L5) is rich in Ca and P. The massive non-phosphatizated section (L3) contains high Mn, Ni, and Co, whereas the porous non-phosphatizated portion (L1-L2), which comprises detrital quartz and feldspar, is rich in Fe. Variations in properties of the Fe-Mn crust from the OSM-XX reflect changes in the nearby marine environment. The formation of this crust started at approximately 51.87 Ma, and precipitation of the CFA during the global phosphatization event that occurred at approximately 36-32 Ma highlights an elevated sea level and low temperature during the associated period. The high Mn, Ni, and Co concentrations and elevated Mn/Fe ratios of samples from the massive phosphatizated portion indicate that the oxygen minimum zone (OMZ) was enhanced, and reducing conditions prevailed during the crust formation. The high Fe and low Mn/Fe ratios in the porous portion indicate a weak OMZ and dominantly oxidizing conditions. These data reflect environmental changes following the end of the Mi-1 glacial period in the Miocene-Oligocene boundary. Subsequently, Mn/Fe and Co/Mn ratios increased slightly in the outermost part of Fe-Mn crust because of the enhanced bottom current and OMZ associated with the continued cooling from approximately 9 Ma. However, the reduced carbonate dissolution rate in the Pacific Ocean from approximately 6 Ma decreased the growth rate of the Fe-Mn crust.