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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Ocean and Polar Research
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Journal DOI :
Korea Institute of Ocean Science & Technology
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Volume & Issues
Volume 28, Issue 4 - Dec 2006
Volume 28, Issue 3 - Sep 2006
Volume 28, Issue 2 - Jun 2006
Volume 28, Issue 1 - Mar 2006
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Holocene Glaciomarine Sedimentation and Its Paleoclimatic Implication on the Svalbard Fjord in the Arctic Sea
Yoon, Ho-Il ; Kim, Yea-Dong ; Yoo, Kyu-Cheul ; Lee, Jae-Il ; Nam, Seung-Il ;
Ocean and Polar Research, volume 28, issue 1, 2006, Pages 1~12
DOI : 10.4217/OPR.2006.28.1.001
Analyses of sedimentological and geochemical parameters from two radiocarbon-dated sediment cores (JM98-845-PC and JM98-818-PC) retrieved from the central part of Isfjorden, Svalbard, in the Arctic Sea, reveal detailed paleoclimatic and paleoceanographic histories over the last 15,000 radiocarbon years. The overconsolidated diamicton at the base of core JM98-845-PC is supposed to be a basal till deposited beneath pounding glacier that had advanced during the LGM (Last Glacial Maximum). Deglaciation of the fjord commenced after the glacial maximum, marked by the deposition of interlaminated sand and mud in the ice-proximal zone by subglacial meltwater discharge, and prevailed between 13,700 and 10,800 yr B.P. with enriched-terrigenous organic materials. A return to colder conditions occurred at around 10,800 yr B.P. with a drop in TOC content, which is probably coincident with the Younger Dryas event in the North Atlantic region. At this time, an abrupt decrease of TOC content as well as an increase in C/N ratio suggests enhanced terrigenous input due to the glacial readvance. A climatic optimum is recognized between 8,395 and 2,442 yr B.P., coinciding with 'a mid-Holocene climatic optimum' in Northern Hemisphere sites (e.g., the Laurentide Ice sheet). During this time, as the sea ice receded from the fjord, enhanced primary productivity occurred in open marine conditions, resulting in the deposition of organic-enriched pebbly mud with evidence of TOC maxima and C/N ratio minima in sediments. Fast ice also disappeared from the coast, providing the maximum of IRD (ice-rafted debris) input. Around 2,442 yr B.p. (the onset of Neoglacial), pebbly mud, characterized by a decrease in TOC content, reflects the formation of more extensive sea ice and fast ice, which might cause decreased primary productivity in the surface water, as evidenced by a decrease in TOC content. Our results provide evidence of climatic change on the Svalbard fjords that helps to refine the existence and timing of late Pleistocene and Holocene millennial-scale climatic events in the Northern Hemisphere.
Meiobenthic Community Structures on the Sediment of Seagrass Bed and Mangrove Forest in Chunk Lagoon, Micronesia
Min, Won-Gi ; Kim, Dong-Sung ; Kwon, Moon-Sang ;
Ocean and Polar Research, volume 28, issue 1, 2006, Pages 13~23
DOI : 10.4217/OPR.2006.28.1.013
This study was conducted to investigate the community structure and distributional pattern of meiobenthos on the sediment of the mangrove forest and seagrass bed in the Chuuk lagoon. The samples were collected by an acryl corer at 14 stations. Nematodes were the most abundant meiobenthos, followed by ciliophorans and polychaetes; these taxa comprised more than 70% of the total abundance at all stations. The meiofuuna sampled in seagrass bed were more diverse than those of mangrove substrates. Total densities were higher in mangrove stations than other sites, averaging 1,671 to
. Densities in seagrass area ranged between 605 and
. Biomasses, however, were higher in seagrass bed
than in mangrove area
. Ordination chart by MDS of major meiofaunal density in each station showed difference between mangrove area and seagrass area in terms of habitat of meiobenthos.
Evaluating the Economic Effects of Fishing Vessel Buyback Programs in Korea
Pyo, Hee-Dong ;
Ocean and Polar Research, volume 28, issue 1, 2006, Pages 25~35
DOI : 10.4217/OPR.2006.28.1.025
Fisheries buyback programs have been implemented from 1994 in Korea, and its scale is estimated to have a value of 930 billion won, which is compounded for eight years since 1994. The paper evaluates the programs' economic and financial viability, and predicts efficient ways about how much and how long to reduce fisheries vessels so as to pursue a target biomass at MSY, For the specific purpose of the paper, aggregate fisheries stock dynamics and catch functions are specified and estimated by yearly catch and fishing effort data from 1970 to 2001, using ASPIC model and Schaefer's logistic production model. Results show that the fisheries stock in Korea has steadily declined since 1970, and that Korean fisheries overexploitation has steadily increased. Using cost-benefit analysis method, the buyback program holds the economic and financial feasibility even if the scale of buyback programs is not sufficient to avoid the downward trend in fisheries stock and harvest. The potential investment scale is predicted in several alternative scenarios using the sensitivity analysis method. The results recommend the annual reduction of 46%, 12% or 20% for the next one year, five years or three years, respectively so that the target biomass at MSY may be reached in 25 years.
Antioxidant Activity and Contents of Bioactive Components in Polar Microalgae
Ha, Tae-Youl ; Kang, Sung-Ho ; Kwon, Tae-Youn ; Ahn, Ji-Yun ; Kim, Sung-Ran ; Kim, Dong-Soo ;
Ocean and Polar Research, volume 28, issue 1, 2006, Pages 37~43
DOI : 10.4217/OPR.2006.28.1.037
In this study, bioactive components such as polyohenols, flavonoids and tocopherols were determined in cultured polar microalgae (Fragilariopsis pseudonana, Chaetoceros neogracile, Stellarima microtrias, Porosiara pseudodenticular). Antioxidant activity of methanol extracts of polar microalgae was also investigated.
contents in Fragilariopsis pseudonana were almost two times higher than those of Chaetoceros neogracile in. The antioxidant activity of methanol extracts of Fragilariopsis pseudonana methanol extracts determined by ABTS assay was higher than other algae. Total polyphenol contents of methanol extracts also showed a similar trend as antioxidant activity. The protective activity against oxidative damages induced by glutamate in PC 12 cells was shown in only Chaetoceros neogracile.
Compound Effect of Persistent Organic Pollutants on the Mortality of Marine Copepods
Kang, Jung-Hoon ; Kim, Woong-Seo ;
Ocean and Polar Research, volume 28, issue 1, 2006, Pages 45~56
DOI : 10.4217/OPR.2006.28.1.045
This study investigated primarily the toxic effects of bis(tributyltin)oxide (TBT) and DDT (Dichlorodiphenyltrichloroethane) on the mortality of adult Acartia omorii and barnacle nauplii as well as the hatching rate of A. omorii. Subsequently, compound effects of TBT and DDT on the mortality of immature copepods were tested in order to assess whether or not synergistic influence existed in the mixture of sublethal concentration of two pollutants. Mortality of adult A. omorii increased as exposure concentration of DDT increased in the range of from 0.0001 to 1ppm. Egg hatching rate of the copepod showed no distinctive difference in the range between 0.1 and 10ppm, while barnacle nauplii showed abnormal motility of their appendages in the range of 0.0001 to 1 ppm. Mortality of adult A. omorii increased as TBT concentration increased within the range of 1 and 10 ppb, whereas egg hatching rate of the copepod showed no linear response to the same exposure range. Moreover, copepod nauplii were almost motionless even though copepod eggs hatched under the exposure condition of TBT
, respectively, suggesting that the nauplii are hard to develop into adult stage. On the basis of the sublethal concentration less than the 24-h
, 0.001 ppm (DDT) and 2 ppb (TBT) were selected to confirm the compound effects of two pollutants on the mortality of immature copepods. Mortality of immature copepods under the condition of mixture of the two pollutants was higher than that in the single exposure condition. This result seems to indicate that synergistic effects of sublethal toxicants can make a more hazardous effect on the survival of immature copepods even though the concentration of single toxicant is not lethal to copepods in the marine environment.
Marine Plankton in Ballast Water of Ship Entering Korea
Yoo, Jeong-Kyu ; Song, Tae-Yoon ; Hong, Hyun-Pyo ; Jeong, Kyung-Mi ; Myung, Chul-Soo ;
Ocean and Polar Research, volume 28, issue 1, 2006, Pages 57~65
DOI : 10.4217/OPR.2006.28.1.057
Various marine plankton were observed in the ballast water of vessels entering Incheon and Busan harbors. The ballast water of which age ranged from 2 to 54 days originated from the coastal waters of New Zealand, Taiwan, Singapore, Japan, Hong Kong and Pakistan, and from the Pacific Ocean. The total number of marine plankton taxa in 9 ballast tanks of different ships was 170: 90 phytoplankton, 24 protozoa and 56 zooplankton. The most diverse taxonomic groups were diatoms in phytoplankton, ciliates in protozoa and copepods in zooplankton. Classifying the specimens by size, above 50% of the number species of phytoplankton belonged to the size range between 50 and 150 Un. Protozoa and metazooplankton were found frequently in the size range between 50 and
and 500 and
, respectively. The relationship between the species number and the age of ballast water was not significant. This is because of difference of filtration amounts derived from discordance of collecting samples. Among plankton observed in ballast water, some harmful algae and non-indigenous aquatic species were identified. Therefore, we need to investigate whether these species can inhabit in Korean coastal waters in further study.