• Title/Summary/Keyword: 延安

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Isotopic Determination of Food Sources of Benthic Invertebrates in Two Different Macroalgal Habitats in the Korean Coasts (동위원소 분석에 의한 동해와 남해 연안의 상이한 해조류 군락에 서식하는 저서무척추동물 먹이원 평가)

  • Kang, Chang-Keun;Choy, Eun-Jung;Song, Haeng-Seop;Park, Hyun-Je;Soe, In-Soo;Jo, Q-Tae;Lee, Kun-Seop
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.12 no.4
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    • pp.380-389
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    • 2007
  • Stable carbon and nitrogen isotopes were analyzed in suspended particulate organic matter, macroalgae and macrobenthic invertebrates in order to determine the importance of primary organic matter sources in supporting food webs of rocky subtidal and intertidal macroalgal beds in the Korean coasts. Investigations were conducted at the inter tidal sites within Gwangyang bay, a semi-enclosed and eutrophicated bay, and the subtidal sites of the east coast, a relatively oligotrophic and open environment, in May and June 2005. Water-column suspension feeders showed more negative $\delta^{13}C$ values than those of the other feeding guilds, indicating trophic linkage with phytoplankton and thereby association with pelagic food chains. In contrast, animals of the other feeding guilds, including interface suspension feeders, herbivores, deposit feeders, omnivores and predators, displayed relatively less negative $\delta^{13}C$ values than those of the water-column suspension feeders and similar with that of macroalgae, indicating exclusive use of macroalgae-derived organic matter and association with benthic food chains. Most the macrobenthic species were considered to form strong trophic links with benthic food chains. In addition, the distribution of higher $\delta^{15}N$ values in macrobenthic consumers and macroalgae at the intertidal sites of Gwangyang Bay than those at the subtidal sites of the east coast suggests that anthropogenic nutrients may enhance the macroalgal production at the intertidal sites and in turn be incorporated into the particular littoral food web in Gwangyag Bay. These results confirm the dominant role of macroalgae in supporting rocky subtidal and intertidal food webs in the Korean coasts.

Sea Level Variability at a Synoptic Band along the East Coast of Korea and its Causal Mechanism (한국 동해연안의 종관주기 해수면 변동 특성과 발생원인)

  • Jung, Sung-Yun;Yun, Jae-Yul;Park, Tae-Wook;Lim, Se-Han;Oh, Im-Sang
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.13 no.2
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    • pp.89-105
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    • 2008
  • Sea level and atmospheric pressure data of 1999-2005 from four stations along the Korean east coast were analyzed to understand the sea level variability and its causal mechanism. The results of the wavelet and the auto-spectrum analyses indicate that the sea level fluctuations of 3-17 day period are statistically significant at the 95% confidence level, especially in spring to early summer. In this period, the coherency between the sea levels and the atmospheric pressures in a cross-spectrum is high, implying the importance of an inverted barometric effect in generation of the sea level fluctuations. To learn about the sea level variability, the cross-spectrum analyses were applied between the sea levels of the adjacent stations. The results show a case of southward phase propagations along the coast, as in 1999, 2003 and 2005, and an another case of no progressive phase lags between the stations, as in 2000-2002, and 2004. The phase speed in the former case is 12-15 m/s, which is a commonly observed phase speed of coastal Kelvin waves. Generation of such fluctuations seems to be related to low pressure cells developed in the Asian continent in spring and summer and moving eastward over the coastal region north of the stations. The latter case of no progressive phase lag, however, occurs when the low pressure cells developed in the continent move along the region south of the stations. In this case, the northeastward phase propagation with a speed of 5-8 m/s is observed along the southwestern coast of Japan.

Analysis of Effect on Domestic Shipping and Logistics Network due to COVID-19 Pandemic -Focusing on the Small-sized Ports of Coastal Ferry Routes in Jeollanamdo Province- (글로벌 팬데믹에 따른 국내 해운물류 네트워크 변화 분석 -전남지역 연안 여객 항로의 소규모 항만을 중심으로-)

  • Son, Yoo-Mi;Kim, Hwa-Young
    • Journal of Korea Port Economic Association
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    • v.40 no.3
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    • pp.175-186
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    • 2024
  • This study analyzes the changes in the coastal ferry transport network in South Korea due to the significant impact of the COVID-19 pandemic on the domestic shipping and logistics sector. Focusing on the small-sized ports network distributed across mainland and islands that make up the coastal ferry transport network, the research employs Social Network Analysis (SNA) methods to examine the structural changes and characteristics of the network from 2018 to 2021, distinguishing between the periods before and after the COVID-19 pandemic. By utilizing centrality indices such as the degree centrality, closeness centrality, and betweenness centrality, the study assesses the changes in the influence of small-sized ports within the network before and after the COVID-19 pandemic. The scope of this study focuses on Mokpo and Wando region in the Jellanamdo province, which have the largest coastal ferry transport networks and notable passenger transport performance in South Korea. It examines the primary ports in these regions and the small-sized ports located on the islands. Analysis of the Mokpo coastal ferry transport network indicates that the number of connected islands decreased before and after the pandemic, and connectivity to other islands within the network diminished. Factors such as the decline in tourist numbers due to COVID-19, the connecting with land bridges between the mainland and islands, and subsequent closure of ferry sea routes are believed to have impacted these network changes. In the Wando region, the sharp decrease in both island residents and tourists after the pandemic led to the suspension of ferry operations, resulting in disrupted connectivity with some small-sized ports on the coastal ferry transport network. This has affected network characteristics such as concentration and average path length in the Wando region. This study aims to analyze the changes in the domestic shipping and logistics, coastal ferry, network due to the COVID-19 pandemic, providing insights to predict potential network changes caused by uncertain events in the future and contributing to the formulation of proactive policies for effective responses.

어항소식

  • 한국어항협회
    • Monthly Newsletter
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    • no.164
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    • pp.1-4
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    • 2001
  • 한국어항협회 전문성을 인정 어항 청소$\cdot$연안정화 업무 강화 - 개정 어항법시행령 신$\cdot$구조문대비표 - 어항공사시공관리의 첫걸음[57]

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