• Title/Summary/Keyword: west coast

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Histological Study on the Reproductive Cycle of Potamocorbula amurensis (Bivalvia: Corbulidae) (계화도조개 (Potamocorbula amurensis)의 생식주기에 관한 조직학적 연구)

  • LEE Ju Ha
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.32 no.5
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    • pp.629-636
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    • 1999
  • Gonadal development, gametogenesis, reproductive cycle, egg-diameter and composition, condition factor, and the first sexual maturity of the clam, Potamocorbula amurensis were investigated by histological observation. Samples were collected monthly from the tidal flat of Moonpo, Puan-gun, Chollabuk-do, west coast of Korea from November 1996 to October 1997. P. amurensis is dioecious and oviparous. The gonads were composed of a number of gametogenic follicles. The oogonia and fully ripe oocytes were $9\~12\mu$m and $50\~60\mu$m in diameter, respectively. Each of the spermatogenic follicle formed stratified layers composed of spermatogonia, spermatocytes spermatids, and spermatozoa in groups on the follicular wall. The reproductive cycle of P. amurensis could be classified into five successive stages: early active, late active, ripe, partially spawned, and recovery. Spawning occurred twice a year from May to July and from September to October, the main spawning seasons also appeared twice a year between May and June, and in October when the water temperatures reached above $18^{\circ}C$. The monthly changes in the condition factor were closely related with the reproductive cycle. Minimum size for the sexual maturation of female and male were 8.1 mm in shell length. There were two patterns for the gametogenesis: 1. After spawning, the undischarged ripe oocytes and spermatozoa in the follicles were degenerated and absorbed, but in part, the existing follicles were not contracted significantly and then they took part in new gametogenesis within one or two months (especially, in summer). 2. After spawning, each follicle was contracted, thereafter gametogenesis again occurred in newly formed follicles.

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A Mid-late Maturing Rice Cultivar with High-Quality and Bacterial Blight Resistance "Jinbaek" (벼 중만생 고품질 흰잎마름병 신균계(K3a) 저항성 품종 "진백")

  • Kim, Ki-Young;Shin, Mun-Sik;Kim, Bo-Kyeong;Ko, Jae-Kwon;Noh, Tae-Hwan;Ha, Ki-Yong;Ko, Jong-Cheol;Kim, Woo-Jae;Nam, Jeong-Kwon;Baek, Man-Gee;Noh, Gwang-Il;Park, Hyun-Su;Baek, So-Hyeon;Shin, Woon-Chul;Mo, Young-Jun;Choung, Jin-Il;Kim, Young-Doo;Kang, Hyun-Jung;Kim, Chung-Kon;Hwang, Hung-Goo;Kim, Je-Kyu
    • Korean Journal of Breeding Science
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    • v.41 no.3
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    • pp.314-318
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    • 2009
  • A new rice cultivar "Jinbaek" carrying Xa3 and xa5 was derived from the cross between 'HR15204-38-3' with xa5 gene resistant to bacterial blight K1, K2, K3 and K3a, and F1 plant derived from the cross between Junam and Sindongjin with Xa3 gene. "Jinbaek" has approximately 125 days of growth duration from transplanting to harvesting in the west-southern coastal and Honam plain of Korea. Culm length of "Jinbaek" is 71 cm. In reaction to biotic stresses, it shows moderate resistance to blast, and wide spectrum resistance to bacterial blight pathogen, K1, K2, K3, and K3a but susceptible to rice stripe virus and blast. The milled rice of "Jinbaek" exhibits translucent, relatively clear non-glutinous endosperm and midium short grain. It has lower amylose content (18.8%) and protein content (6.2%) compared with Nampyeong. The milled rice yield of this cultivar was 5.30 MT/ha in local adaptability test of three years from 2006 to 2008. This cultivar would be adaptable to the bacterial blight-prone area in the south-western coast and Honam plain of Korea.

Investigation of Intertidal Zone using TerraSAR-X (TerraSAR-X를 이용한 조간대 관측)

  • Park, Jeong-Won;Lee, Yoon-Kyung;Won, Joong-Sun
    • Korean Journal of Remote Sensing
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    • v.25 no.4
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    • pp.383-389
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    • 2009
  • The main objective of the research is a feasibility study on the intertidal zone using a X-band radar satellite, TerraSAR-X. The TerraSAR-X data have been acquired in the west coast of Korea where large tidal flats, Ganghwa and Yeongjong tidal flats, are developed. Investigations include: 1) waterline and backscattering characteristics of the high resolution X-band images in tidal flats; 2) polarimetric signature of halophytes (or salt marsh plants), specifically Suaeda japonica; and 3) phase and coherence of interferometric pairs. Waterlines from TerraSAR-X data satisfy the requirement of horizontal accuracy of 60 m that corresponds to 20 cm in average height difference while current other spaceborne SAR systems could not meet the requirement. HH-polarization was the best for extraction of waterline, and its geometric position is reliable due to the short wavelength and accurate orbit control of the TerraSAR-X. A halophyte or salt marsh plant, Suaeda japonica, is an indicator of local sea level change. From X-band ground radar measurements, a dual polarization of VV/VH-pol. is anticipated to be the best for detection of the plant with about 9 dB difference at 35 degree incidence angle. However, TerraSAR-X HH/TV dual polarization was turned to be more effective for salt marsh monitoring. The HH-HV value was the maximum of about 7.9 dB at 31.6 degree incidence angle, which is fairly consistent with the results of X-band ground radar measurement. The boundary of salt marsh is effectively traceable specifically by TerraSAR-X cross-polarization data. While interferometric phase is not coherent within normal tidal flat, areas of salt marsh where the landization is preceded show coherent interferometric phases regardless of seasons or tide conditions. Although TerraSAR-X interferometry may not be effective to directly measure height or changes in tidal flat surface, TanDEM-X or other future X-band SAR tandem missions within one-day interval would be useful for mapping tidal flat topography.

A New Medium-Maturing, "Gangbaek" with Resistance to Bacterial Blight (벼 중생 흰잎마름병 저항성 신품종 "강백")

  • Kim, Ki Young;Shin, Mun Sik;Kim, Woo Jae;Ko, Jong Cheol;Baek, Man Gee;Ha, Ki Yong;Kim, Bo Kyeong;Ko, Jae Kwon;Nam, Jeong Kwon;Noh, Gwang Il;Park, Hyun Su;Noh, Tae Hwan;Noh, Jae-Hwan;Cheong, Jin Il;Kim, Young Doo;Mo, Young Jun;Kim, Chung Kon
    • Korean Journal of Breeding Science
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    • v.40 no.4
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    • pp.443-446
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    • 2008
  • 'Gangbaek' is a japonica rice variety developed and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2006. 'Gangbaek' was derived from a cross between 'Suweon345' with good grain quality and 'DV85' resistant to bacterial blight, $K_{3a}$. $F_1$ plants were grown in the greenhouse in winter of 1992/1993 and backcrossed with 'Suweon345' as the recurrent parent. Plants resistant to $K_{3a}$ race of bacterial blight (BB) were selected from $BC_1F_1$ to $BC_4F_1$ and used as parents in the backcrossing processes. This variety has about 120 days growth duration from transplanting to harvesting in west-southern coast and Honam plain of Korea. It is about 69 cm in culm length and tolerance to lodging. In reaction to biotic and abiotic stresses, it shows moderately resistance to blast, and resistance to bacterial blight pathogen, $K_1$, $K_2$, $K_3$ and $K_{3a}$, but susceptible to other major diseases and insect pests. The milled rice of 'Gangbaek' exhibits translucent, relatively clear non-glutinous endosperm and midium short grain. It has lower amylose content of 18.6% and protein content of 6.4% compared with 'Nampyeongbyeo'. The milled rice yield performance of this variety is about 5.28 MT/ha in local adaptability test for three years. This cultivar would be adaptable to the bacterial blight-prone area in the south-western coastal and Honam plain of Korea.

The Ecological Values of the Korean Demilitarized Zone(DMZ) and International Natural Protected Areas (비무장지대(DMZ)의 생태적 가치와 국제자연보호지역)

  • Cho, Do-soon
    • Korean Journal of Heritage: History & Science
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    • v.52 no.1
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    • pp.272-287
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    • 2019
  • The Korean Demilitarized Zone (DMZ) was established in 1953 by the Korean War Armistice Agreement. It extends from the estuary of the Imjin River, in the west, to the coast of the East Sea. It is 4 km in width and 148 km in length. However, the ecosystems of the civilian control zone (CCZ) located between the southern border of the DMZ and the civilian control line (CCL) and the CCZ in the estuary of the Han River and the Yellow Sea are similar to those in the DMZ, and, therefore, the ecosystems of the DMZ and the CCZ are collectively known as the "ecosystems of the DMZ and its vicinities." The flora in the DMZ and its vicinities is composed of 1,864 species, which accounts for about 42% of all the vascular plant species on the Korean Peninsula and its affiliated islands. Conducting a detailed survey on the vegetation, flora, and fauna in the DMZ is almost impossible due to the presence of landmines and limitations on the time allowed to be spent in the DMZ. However, to assess the environmental impact of the Munsan-Gaesong railroad reconstruction project, it was possible to undertake a limited vegetation survey within the DMZ in 2001. The vegetation in Jangdan-myeon, in Paju City within the DMZ, was very simple. It was mostly secondary forests dominated by oaks such as Quercus mongolica, Q. acutissima, and Q. variabilis. The other half of the DMZ in Jangdan-myeon was occupied by grassland composed of tall grasses such as Miscanthus sinensis, M. sacchariflorus, and Phragmites japonica. Contrary to the expectation that the DMZ may be covered with pristine mature forests due to more than 60 years of no human interference, the vegetation in the DMZ was composed of simple secondary forests and grasslands formed on former rice paddies and agricultural fields. At present, the only legal protection system planned for the DMZ is the Natural Environment Conservation Act, which ensures that the DMZ would be managed as a nature reserve for only two years following Korean reunification. Therefore, firstly, the DMZ should be designated as a site of domestic legally protected areas such as nature reserve (natural monument), scenic site, national park, etc. In addition, we need to try to designate the DMZ as a UNESCO Biosphere Reserve or as a World Heritage site, or as a Ramsar international wetland for international cooperation. For nomination as a world heritage site, we can emphasize the ecological and landscape value of the wetlands converted from the former rice paddies and the secondary forests maintained by frequent fires initiated by military activities. If the two Koreas unexpectedly reunite without any measures in place for the protection of nature in the DMZ, the conditions prior to the Korean War, such as rice paddies and villages, will return. In order to maintain the current condition of the ecosystems in the DMZ, we have to discuss and prepare for measures including the retention of mines and barbed-wire fences, the construction of roads and railroads in the form of tunnels or bridges, and the maintenance of the current fire regime in the DMZ.

Vegetation Characteristics of Ridge in the Seonunsan Provincial Park (선운산도립공원의 능선부 식생 특성)

  • Kang, Hyun-Mi;Park, Seok-Gon;Kim, Ji-Suk;Lee, Sang-Cheol;Choi, Song-Hyun
    • Korean Journal of Environment and Ecology
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    • v.33 no.1
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    • pp.75-85
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    • 2019
  • The purpose of this study is to understand the vegetation characteristics of ridges (Gyeongsusan-Seonunsan-Gaeipalsan) in the Seonunsan Provincial Park and to establish reference information for the management of the park in the future. We designated 62 plots with the area of $100m^2$ were installed and analyzed them to investigate the vegetation characteristics. The results of community classification based on TWINSPAN showed seven categories of vegetation communities in the surveyed region: Quercus dentata-Deciduous broad-leaved Community, Quercus variabilis-Pinus thunbergii-Quercus serrata Community, Pinus densiflora Community, Deciduous broad-leaved Community-I, Carpinus tschonoskii-Castanea crenata-Quercus aliena Community, Deciduous broad-leaved Community-II, and Carpinus tschonoskii-Carpinus laxiflora Community. In the vegetation of Seonunsan Provincial Park, coniferous trees such as Pinus thunbergii and Pinus densiflora have been gradually losing their population as part of ecological succession to deciduous broad-leaved trees such as Quercus spp., Carpinus tschonoskii, and Carpinus laxiflora. Moreover, Carpinus turczaninowii, Mallotus japonicus, and others were identified as vegetation reflecting the geographical characteristics of the region neighboring the west coast. The estimated age is 30-60 years, and the oldest tree Pinus densiflora is 63-years old. The index of diversity ($100m^2$) was 0.7942 for Carpinus tschonoskii-Carpinus laxiflora Community, 0.8406 for Carpinus tschonoskii-Castanea crenata-Quercus aliena Community, 0.8543 for Quercus dentata-Deciduous broad-leaved Community, 0.9434 for Quercus variabilis-Pinus thunbergii-Quercus serrata Community, 0.9520 for Deciduous broad-leaved Community-I, 0.9633 for Pinus densiflora Community, and 1.0340 for Deciduous broad-leaved Community-II in the ascending order.

Habitat Climate Characteristics of Lauraceae Evergreen Broad-leaved Trees and Distribution Change according to Climate Change (녹나무과 상록활엽수 자생지 기후특성과 기후변화에 따른 분포 변화)

  • Yu, Seung-Bong;Kim, Byung-Do;Shin, Hyun-Tak;Kim, Sang-Jun
    • Korean Journal of Environment and Ecology
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    • v.34 no.6
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    • pp.503-514
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    • 2020
  • Climate change leads to changes in phenological response and movement of plant habitats. Korea's evergreen broad-leaved forest has widened its distribution area compared for the past 20 years, and the range of its native habitats is moving northward. We analyzed climate indices such as the warmth index, the cold index, the lowest temperature in the coldest month, and the annual average temperature, which are closely related to vegetation distribution, to predict the change in the native habitat of Lauraceae evergreen broad-leaved trees. We also analyzed the change and spatial distribution to identify the habitat climate characteristics of 8 species of Lauraceae evergreen broad-leaved trees distributed in the warm temperate zone in Korea. Moreover, we predicted the natural habitat change in the 21st century according to the climate change scenario (RCP 4.5/8.5), applying the MaxEnt species distribution model. The monthly average climate index of the 8 species of Lauraceae evergreen broad-leaved trees was 116.9±10.8℃ for the temperate index, the cold index 3.9±3.8℃, 1495.7±455.4mm for the annual precipitation, 11.7±3.5 for the humidity index, 14.4±1.1℃ for the annual average temperature, and 1.0±2.1℃ for the lowest temperature of winter. Based on the climate change scenario RCP 4.5, the distribution of the Lauraceae evergreen broad-leaved trees was analyzed to expand to islands of Jeollanam-do and Gyeongsangnam-do, adjacent areas of the west and south coasts, and Goseong, Gangwon-do on the east coast. In the case of the distribution based on the climate change scenario RCP 8.5, it was analyzed that the distribution would expand to all of Jeollanam-do and Gyeongsangnam-do, and most regions except for some parts of Jeollabuk-do, Chungcheongnam-do, Gyeongsangbuk-do, and the capital region. For the conservation of Lauraceae evergreen broad-leaved trees to prepare for climate change, it is necessary to establish standards for conservation plans such as in-situ and ex-situ conservation and analyze various physical and chemical characteristics of native habitats. Moreover, it is necessary to preemptively detect changes such as distribution, migration, and decline of Lauraceae evergreen broad-leaved trees following climate change based on phenological response data based on climate indicators and establish conservation management plans.

Experimental Transplantation for the Restoration of Seagrass, Zostera marina L. Bed Around Sinyangseopji Beach in Bangdu Bay, Jeju Island (제주 신양섭지해수욕장 주변 방두만 거머리말 군락 복원을 위한 실험적 이식)

  • LEE, HYUNG WOO;KANG, JEONG CHAN;PARK, JUNG-IM;KIM, MYUNG SOOK
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.26 no.4
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    • pp.343-355
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    • 2021
  • Eelgrass, Zostera marina L., was widely distributed around Sinyangseopji Beach in Bangdu Bay, on the eastern coast of Jeju Island, until breakwater construction in the late 1990s resulted in its complete loss. Six experimental sites were identified for restoration of the Z. marina bed in Bangdu Bay. Using the staple method, 500 Z. marina shoots were transplanted at each site in January 2019 and 2020. The transplants, along with environmental parameters, were monitored for 10 months following transplantation. There were significant differences in underwater irradiance, water temperature, and salinity among the sites, but all were suitable for Z. marina growth. The Ulva species, an opportunistic alga, appeared in spring and accumulated during summer at all sites; however, there was no significant effect of Ulva species on the survival and growth of the eelgrass transplants. Most of the transplanted Z. marina survived, and after 3 months, the density increased by 112.5-300% due to vegetative propagation, with a rapid rate of increase observed during spring and early summer at all sites. For 1-2 months after transplanting, the Z. marina shoots showed signs of transplant shock, after which the shoot density increased at all sites, confirming that all transplants adapted well to the new environment. However, in both 2019 and 2020, during late summer to early fall, the sites experienced heavy damage from typoons (twice in 2019 and three times in 2020) that hit Bangdu Bay. The transplants at two sites located in the center of Bangdu Bay were completely destroyed, but those at three sites located to the west of the bay showed a 192-312% increase in density. Thus, we confirmed that the Bangdu Bay Z. marina bed can be restored, with the highest probability of success for Z. marina restoration on the western side of Bangdu Bay, which is protected from typhoons.

Extraction and Analysis of Ganghwa Tidal Flat Channels Using TanDEM-X DEM (TanDEM-X DEM을 이용한 강화도 갯벌 조류로 추출과 분석)

  • Yun, Ga-Ram;Kim, Lyn;Kim, Nam-Yeong;Kim, Na-Gyeong;Jang, Yun-Yeong;Choi, Yeong-Jin;Lee, Seung-Kuk
    • The Journal of Engineering Geology
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    • v.32 no.3
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    • pp.411-420
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    • 2022
  • Recently, research using remote sensing has been active in various fields such as environment, science, and society. The results of research using remote sensing are not only numerical results, but also play an important role in solving and preventing social and scientific problems. The purpose of this thesis is to tell the correlation between the data provided and each data by using remote sensing technology for the tidal flat environment. The purpose of this study is to obtain high-resolution data using artificial satellites during remote sensing to find out information on tidal flat currents. Tidal flats created by erosion, sedimentation, low tide, and high tide contain information about the tidal flat slope and information about the ecosystem. Therefore, it can be considered as one of the very important studies to analyze the overall tidal flow channel. This paper creates a DEM (Digital Elevation Model) through TanDEM-X, and DEM is used as the most basic data to create a tidal channel. The research area is a tidal flat located in the middle of the west coast of Ganghwado tidal flat. By analyzing the tidal channel created, various information such as the slope direction of Ganghwado tidal flat and the shape of the tidal channel can be grasped. It is expected that the results of this study will increase the importance and necessity of using DEM data for tidal flat research in the future, and that high-quality results can be obtained.

A preliminary assessment of high-spatial-resolution satellite rainfall estimation from SAR Sentinel-1 over the central region of South Korea (한반도 중부지역에서의 SAR Sentinel-1 위성강우량 추정에 관한 예비평가)

  • Nguyen, Hoang Hai;Jung, Woosung;Lee, Dalgeun;Shin, Daeyun
    • Journal of Korea Water Resources Association
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    • v.55 no.6
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    • pp.393-404
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    • 2022
  • Reliable terrestrial rainfall observations from satellites at finer spatial resolution are essential for urban hydrological and microscale agricultural demands. Although various traditional "top-down" approach-based satellite rainfall products were widely used, they are limited in spatial resolution. This study aims to assess the potential of a novel "bottom-up" approach for rainfall estimation, the parameterized SM2RAIN model, applied to the C-band SAR Sentinel-1 satellite data (SM2RAIN-S1), to generate high-spatial-resolution terrestrial rainfall estimates (0.01° grid/6-day) over Central South Korea. Its performance was evaluated for both spatial and temporal variability using the respective rainfall data from a conventional reanalysis product and rain gauge network for a 1-year period over two different sub-regions in Central South Korea-the mixed forest-dominated, middle sub-region and cropland-dominated, west coast sub-region. Evaluation results indicated that the SM2RAIN-S1 product can capture general rainfall patterns in Central South Korea, and hold potential for high-spatial-resolution rainfall measurement over the local scale with different land covers, while less biased rainfall estimates against rain gauge observations were provided. Moreover, the SM2RAIN-S1 rainfall product was better in mixed forests considering the Pearson's correlation coefficient (R = 0.69), implying the suitability of 6-day SM2RAIN-S1 data in capturing the temporal dynamics of soil moisture and rainfall in mixed forests. However, in terms of RMSE and Bias, better performance was obtained with the SM2RAIN-S1 rainfall product over croplands rather than mixed forests, indicating that larger errors induced by high evapotranspiration losses (especially in mixed forests) need to be included in further improvement of the SM2RAIN.