• Journal of the Mineralogical Society of Korea
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• v.19 no.3 s.49
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• pp.163-169
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• 2006

Mineralogy and geochemistry of the sediment core from the seamount (2710 m below the sea level) just south of the Antarctic Polar Front were examined to draw paleoceanographic information in glacial-interglacial cycles. Smectite was most abundant clay mineral associated with illite and chlorite. Its content was slightly higher below 170 cm, suggesting a boundary between isotope stage 4 and 5. Si, Zr, Cs, Th, REE, $K_{2}O$, and $Al_{2}O_{3}$ show complete antithetical distribution with respect to $CaCO_{3}$ through the core. $SiO_{2}$ maxima and $CaCO_{3}$ minima at depths of 24, 136, and 176 cm are probably correlated with massive influx of ice-rafted debris during the advance of Antarctic ice shelves. Ni, Cu, and Ba show rather little correlation with $SiO_{2}$, suggesting their relation to biogenic debris, precipitation from seawater, or hydrothermal input. Particularly, Ba maxima tend to lag $10{\sim}20cm$ after $SiO_{2}$ maxima, probably due to rapid increase of productivity following deglaciation.

• Journal of the Mineralogical Society of Korea
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• v.15 no.1
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• pp.22-32
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• 2002

Mineral composition and chemistry of the clay minerals in the three cores from the continental shelves of South Shetland Islands (NCS09) and Anberse Island (GC98-2), and from the fjord of King George Island (A10-01) were determined by X-ray diffraction and electron microprobe analysis in search of the distributions and origin of the clay minerals in the Antarctic marine sediments. Smectite content is relatively high in NCS09 regardless of core depths (av. 8.3%), but low in GC98-2 (1.1%). In Al0-01, smectite content is higher in the upper section than in the lower section. Kaolinite was not detected from all the cores in this study Yellow to yellowish green clay granules were commonly scattered in the sediments of NCS09 cores. The clays contain 16.97% and 2.53% $Fe_2$$O_3$와 $K_2$O. Average structural formula of the clay indicates ferrian beidellite . The (Fe, K)-rich smectite of NSC09 must have been derived from relatively young basaltic volcanics altered by reaction with seawater near Shetland Islands by glacial erosion or eolian process related to volcanic eruption. GC98-2 nearer to Antarctic continent is very low in smectite content. In A10-01, the lower diamicton was deposited from the glacial erosion of smectite-free ancient volcanics in the interior of King George Island, while the upper section was derived from the smectite-bearing terrestrial debris and eolian materials after retreat of glaciers in Marian Cove and ice cover in Barton Peninsula. Thehigh K contents of smectites suggest the interstratification of illite and smectite layers, which might be observed by future TEM lattice fringe imaging.

• Journal of the Korean Institute of Gas
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• v.10 no.4 s.33
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• pp.34-40
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• 2006

This paper provides a fusion technology between a district cooling energy system and an environment conservation policy based on the energy savings and reusable cold energy resources. The district heating and cooling systems are very effective ways for an energy saving, a cost reduction and a safety control. It is necessary to equalize the energy savings and an environmental preservation policy for an improved human lift. A gasification process of a liquefied natural gas, cooling water from deep seawater and an ice water thermal storage system may produce a cold energy. A district cooling system is used to cool an apartment, office buildings and factory facilities with a cooling energy supply pipeline. LNG cooling energy will switch a conventional air-conditioning system, which is operated by on electrical energy and a Freon refrigerant. Coincident with significant clean energy and operating cost savings, LNG cold energy system owen radical reductions in an air-borne pollutant, $CO_2$ and the release of environmentally harmful refrigerants compared with that of the conventional air-conditioning system. This study provides useful information on the fusion technology of a LNG cold energy usage and energy savings, and environmental conservation.

• Fisheries and Aquatic Sciences
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• v.22 no.11
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• pp.26.1-26.7
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• 2019

Background: The monitoring of pathogens of fishery auction markets is important to obtain safe fishery products regarding hygiene and sanitation. In this study, aerobic, coliform, Escherichia coli, and Vibrio cholerae were monitored in the fishery products and environmental samples obtained from fishery auction markets. Methods: The fishery products (flounder, octopus, skate, rock cod, sea bass, snail, monkfish, flatfish, comb pen shell, corb shell, conger eel, hairtail, croaker, and pilchard) were placed in filter bags, and the environmental samples (samples from the water tanks at the fishery auction markets, seawater from the fishery distribution vehicles, ice from wooden or plastic boxes, and surface samples from wooden and plastic boxes used for fish storage) were collected. Aerobic bacteria, E. coli, and coliform in the samples were enumerated on aerobic count plates and E. coli/coliform count plates, respectively. For V. cholerae O1 and V. cholerae non-O1 quantification, most probable number (MPN)-PCR analysis was performed. Results: Aerobic and coliform bacteria were detected in most samples, but E. coli was not detected. Wooden boxes were contaminated with high levels of aerobic and coliform bacteria in all seasons (spring, summer, and fall). During fall, V. cholerae non-O1 were detected in snails, hairtails, croakers, flatfishes, pilchards, plastic boxes, and water samples. Conclusions: These results indicate an increased prevalence of V. cholerae contamination in fishery products in fall, including food contact samples, which can be vehicles for cross-contamination.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.73-73
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• 2003

The present study examined the possibility of long term storage, by cryopreservation in liquid nitrogen, of the sperm of Filefish (Thamnaconus septentrionalis), and the changes in motility, survival rate and ultrastructure of the sperm after freezing and thawing. The sperm was collected by stripping and stored on ice until experiments. For selection of the immobilizing solution, diluted artificial seawater (ASW) of 20, 30 and 40% were tested. The sperm motility was significantly inhibited in 30% ASW, and restored entirely after 100% ASW was added again. Two cryoprotectants, dimethyl sulfoxide ($Me_2$SO) and glycerol, were added to 30% ASW to formulate the extenders at the concentrations between 5 to 20% by volume for freezing. The sperm was diluted at the ratio of 1 :6 with the extenders, inserted into 0.5ml plastic straws and frozen at a freezing rate of $50^{\circ}C$/min to $-100^{\circ}C$ after equilibration for 10 min at room temperature, followed by plunging into liquid nitrogen. The straws were thawed in a $30^{\circ}C$ water bath for 15 sec. The highest post-thawed sperm motility and survival rate were obtained with 5% glycerol Afterward, the effect of different freezing rates was examined using 5% glycerol as a cryoprotectant, and the rate of $20^{circ}C/min to $-80^{\circ}C$ showed the best result Some ultrastructural changes of sperm, such as the detachment of plasmatic and nuclear membranes, destruction of mitochondria, were observed after cryopreservation. Morphological normality of the sperm in 5% glycerol frozen at the ratio of 1$0^{\circ}C$/min to $-80^{\circ}C$ was better than that of others.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.28 no.1
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• pp.1-18
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• 2023

The East Sea, one of the regions where the most rapid warming is occurring, is known to have important implications for the response of the ocean to future climate changes because it not only reacts sensitively to climate change but also has a much shorter turnover time (hundreds of years) than the ocean (thousands of years). However, the processes underlying changes in seawater characteristics at the sea's deep and abyssal layers, and meridional overturning circulation have recently been examined only after international cooperative observation programs for the entire sea allowed in-situ data in a necessary resolution and accuracy along with recent improvement in numerical modeling. In this review, previous studies on the physical characteristics of seawater at deeper parts of the East Sea, and meridional overturning circulation are summarized to identify any remaining issues. The seawater below a depth of several hundreds of meters in the East Sea has been identified as the Japan Sea Proper Water (East Sea Proper Water) due to its homogeneous physical properties of a water temperature below 1℃ and practical salinity values ranging from 34.0 to 34.1. However, vertically high-resolution salinity and dissolved oxygen observations since the 1990s enabled us to separate the water into at least three different water masses (central water, CW; deep water, DW; bottom water, BW). Recent studies have shown that the physical characteristics and boundaries between the three water masses are not constant over time, but have significantly varied over the last few decades in association with time-varying water formation processes, such as convection processes (deep slope convection and open-ocean deep convection) that are linked to the re-circulation of the Tsushima Warm Current, ocean-atmosphere heat and freshwater exchanges, and sea-ice formation in the northern part of the East Sea. The CW, DW, and BW were found to be transported horizontally from the Japan Basin to the Ulleung Basin, from the Ulleung Basin to the Yamato Basin, and from the Yamato Basin to the Japan Basin, respectively, rotating counterclockwise with a shallow depth on the right of its path (consistent with the bottom topographic control of fluid in a rotating Earth). This horizontal deep circulation is a part of the sea's meridional overturning circulation that has undergone changes in the path and intensity. Yet, the linkages between upper and deeper circulation and between the horizontal and meridional overturning circulation are not well understood. Through this review, the remaining issues to be addressed in the future were identified. These issues included a connection between the changing properties of CW, DW, and BW, and their horizontal and overturning circulations; the linkage of deep and abyssal circulations to the upper circulation, including upper water transport from and into the Western Pacific Ocean; and processes underlying the temporal variability in the path and intensity of CW, DW, and BW.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.3
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• pp.134-144
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• 2009

Paleoproductivity changes in the central part of the Bering Sea since the last glacial period were reconstructed by analyzing opal and total organic carbon (TOC) content and their mass accumulation rate (MAR) in sediment core PC23A. Ages of the sediment were determined by both AMS $^{14}C$ dates using planktonic foraminifera and Last Appearance Datum of radiolaria (L. nipponica sakaii). The core-bottom age was calculated to reach back to 61,000 yr BP. and some of core-top was missing. Opal and TOC contents during the last glacial period varied in a range of 1-10% and 0.2-1.0%, and their average values are 5% and 0.7%, respectively. In contrast, during the last deglaciation, opal and TOC contents varied from 5 to 22% and from 0.8 to 1.2%, respectively, with increasing average values of 8% and 1.0%. Opal and TOC MAR were low ($1gcm^{-2}kyr^{-1}$, $0.2gcm^{-2}kyr^{-1}$) during the last glacial period, but they increased (>5 and >$1gcm^{-2}kyr^{-1}$) during the last deglaciation. High diatom productivity during the last deglaciation was most likely attributed to the elevated nutrient supply to the sea surface resulting from increased melt water input from the nearby land and enhanced Alaskan Stream injection from the south under the restricted sea-ice and warm condition during the rising sea level. On the contrary, low productivity during the last glacial period was mainly due to decreased Alaskan Stream injection during the low sea-level condition as well as to extensive development of sea ice under low-temperature seawater and cold environment.