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Distribution and Migration of Larval and Juvenile Sandfish Arctoscopus japonicus in the Coastal Waters off Gangwondo, Korea (강원도 연안의 도루묵(Arctoscopus japonicus) 자치어 분포와 회유)

  • Yang, Jae Hyeong;Yoon, Sang Chul;Park, Jeong-Ho;Choi, Young Min;Lee, Jae Bong;Yoon, Byoung Sun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.46 no.5
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    • pp.649-652
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    • 2013
  • Distribution and migration of larval and juvenile sandfish Arctoscopus japonicus in the coastal waters off Gangwondo were determined monthly from samples collected by a rectangular bottom net in the coastal waters off Gangwondo from March to July, 2011. Fish were collected in abundance from the northern waters from March to June. The average total length (±SD) was 11.5±1.6 mm in March increased up to 53.5±3.3 mm in June. The size distribution of sandfish by depth suggested that the fish grew waters less than 50 m deep until June, before moving deeper waters of around 100 m.

Arthonia dokdoensis and Rufoplaca toktoana - Two New Taxa from Dokdo Islands (South Korea)

  • Kondratyuk, Sergij;Lokos, Laszlo;Halda, Josef;Lee, Beeyoung Gun;Jang, Seol-Hwa;Woo, Jeong-Jae;Park, Jung Shin;Oh, Soon-Ok;Han, Sang-Kuk;Hur, Jae-Seoun
    • Mycobiology
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    • v.47 no.4
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    • pp.355-367
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    • 2019
  • Arthonia dokdoensis sp. nov., a lichenicolous fungus from the subcosmopolitan Arthonia molendoi complex growing on crustose thalli of species of the genus Orientophila (subfamily Xanthorioideae, Teloschistaceae), as well as the lichen species Rufoplaca toktoana sp. nov. (subfamily Caloplacoideae, Teloschistaceae) similar to Rufoplaca kaernefeltiana, both from Dokdo Islands, Republic of Korea, are described, illustrated, and compared with closely related taxa. In the phylogenetic tree of the Arthoniaceae based on 12S mtSSU and RPB2 gene sequences, the phylogenetic position of the A. dokdoensis and the relationship with the A. molendoi group are illustrated, while the position of the newly described R. toktoana is confirmed by phylogenetic tree based on ITS nrDNA data.

Characterization of Two New Records of Zygomycete Species Belonging to Undiscovered Taxa in Korea

  • Nguyen, Thi Thuong Thuong;Lee, Seo Hee;Bae, Sarah;Jeon, Sun Jeong;Mun, Hye Yeon;Lee, Hyang Burm
    • Mycobiology
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    • v.44 no.1
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    • pp.29-37
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    • 2016
  • During a biodiversity survey of undiscovered taxa in Korea, two zygomycetous fungal strains were isolated. The first strain, EML-FSDY6-1 was isolated from a soil sample collected at Dokdo Island in the East Sea of Korea in 2013, and the second strain, EML-DG-NH3-1 was isolated from a rat dung sample collected at Chonnam National University garden, Gwangju, Korea in 2014. Based on the morphological characteristics and phylogenetic analysis of the internal transcribed spacer, 18S and 28S rDNA, actin and translation elongation factor1α genes. EML-FSDY6-1 and EML-DG-NH3-1 isolates were confirmed as zygomycete species, Absidia pseudocylindrospora and Absidia glauca, respectively. Neither species has previously been described in Korea.

Mushroom Flora of Ulleung-gun and a Newly Recorded Bovista Species in the Republic of Korea

  • Kim, Chang Sun;Jo, Jong Won;Kwag, Young-Nam;Sung, Gi-Ho;Lee, Sle-gee;Kim, Sang-Yong;Shin, Chang-Ho;Han, Sang-Kuk
    • Mycobiology
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    • v.43 no.3
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    • pp.239-257
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    • 2015
  • We conducted five times surveys, in June, September and October in 2012; June and September 2013, to catalog the mushroom flora in Ulleung-gun, Republic of Korea. More than 400 specimens were collected, and 317 of the specimens were successfully sequenced using the ribosomal DNA internal transcribed spacer barcode marker. We also surveyed the morphological characteristics of the sequenced specimens. The specimens were classified into 2 phyla, 7 classes, 21 orders, 59 families, 122 genera, and 221 species, and were deposited in the herbarium of Korea National Arboretum. Among the collected species, 72% were saprophytic, 25% were symbiotic, and 3% were parasitic. The most common order was Agaricales (189 specimens, 132 species), followed by Polyporales (47 specimens, 27 species), Russulales (31 specimens, 22 species), Boletales (10 specimens, 7 species), and so on. Herein, we also reported the first Bovista species in Korea, which was collected from Dokdo, the far-eastern island of Korea.

First record of Brachaluteres ulvarum (Tetraodontiformes: Monacanthidae) from Jeju-do Island, southern Korea

  • Myoung, Se Hun;Park, Joo Myun;Lee, Hyo Jin;Jawad, Laith A.
    • Fisheries and Aquatic Sciences
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    • v.24 no.6
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    • pp.228-234
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    • 2021
  • A single specimen (39.4 mm standard length) of Brachaluteres ulvarum, belonging to the family Monacanthidae has been recorded for the first time from Supseom, Jeju-do Island of southern Korea on 6 March 2021. This species was characterized by the presence of a small second dorsal spine present, the posterior end of pelvic without encasing scales, and numerous thin dark longitudinal lines on body. It was morphologically similar to the B. taylori, but distinguished by the ratio of the caudal peduncle to the head length (B. ulvarum, 2.5 to 3.7 times; B. taylori, 3.5 to 5.2 times). In addition, the former is well distinguished from the latter through mitochondrial cytochrome c oxidase subunit I (COI) sequences by genetic distances of range from 0.088 to 0.090. The new Korean name "Kko-ma-jwi-chi- sog" is proposed for the genus Brachaluteres, and "Kko-ma-jwi-chi" for the species B. ulvarum.

Petrological Characteristics and Origin of Volcaniclasts within the Massive Tuff Breccia Formation from Dokdo Island, Korea (독도 괴상 응회질 각력암층에서 나타나는 화산암편의 암석학적 특성과 기원)

  • Shim, Sung-Ho;Im, Ji-Hyeon;Jang, Yun-Deuk;Choo, Chang-Oh;Park, Byeong-Jun;Kim, Jung-Hun
    • The Journal of the Petrological Society of Korea
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    • v.19 no.2
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    • pp.141-156
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    • 2010
  • Dokdo Island, Korea, is located in the East Sea belonging to back arc basin. In this study we examined petrology and geochemistry of massive tuffaceous breccia (MTB) from Dongdo (Eastern islet) and Seodo(Western islet), the two largest islands of Dokdo. Field studies and chemical analysis distinguish the MTB in Dongdo and Seodo. The Dongdo MTB (DMTB) is exposed up to 50 m on the ocean cliff and it has dominant basalt and trachybasalt with moderate amount of trachyte and scoria. On the other hand, Seodo MTB (SMTB), which is preserved between trachyte dike and trachyandesite, is composed of roughly equal amounts of basalt, trachybasalt and trachyte. The location of the islets were related to the source vent having in contact with underlying trachyte lava and differential pyroclastic deposits made them different characteristics. According to trace element analysis of trachytic volcanic clasts, the Ba concentration ranges from 66 to 103 ppm and Sr varies from 44 to 56 ppm in DMTB. However, Br and Sr in SMTB correspondingly showed relatively wide ranges: Br 785-1259 ppm and Sr 466-1230 ppm. These differential trends between DMTB and SMTB, along with the difference in P and Ti, indicate that the crystallization of alkali feldspar, feldspathoid, biotite, apatite and titanium took place differently. Nevertheless, DMTB and SMTB are similar in REE patterns and they are correspondingly characterized by high LREE, low HREE and similar (La/Yb)N values with 23.9-40.2 in DMTB and 27.4-32.9 in SMTB. These patterns suggest that Dongdo and Seodo might be originated from coeval magma suites. Dokdo island shows high concentrations of Ba, K and Rb. These signatures mark a result attributed to the mantle upwelling because the magma derived from the asthenosphere was metasomatized with subduction-related fluids.

Seasonal Variation of Picocyanobacterial Community Composition in Seawaters Around Dokdo, Korea (독도 해역 초미소남세균 다양성의 계절적 변동)

  • CHOI, DONG HAN;AN, SUNG MIN;CHOI, YU RI;ROH, HYUN SOO;NOH, JAE HOON
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.20 no.4
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    • pp.192-198
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    • 2015
  • Picophytoplankton, a group of tiny microorganisms of less than 3μm, play an important role as a major primary producer in tropical open ocean as well as temperate coastal waters. Until now, more than 20 and 10 clades of Synechococcus and Prochlorococcus, respectively, have been identified in various marine environments, and its biogeographical distribution have been well studied as well as ecological niches of its major clades. To understand a distribution of diverse picocyanobacterial clades and environmental factors regulating their distribution, picocyanobacterial abundance and genetic diversity was investigated in adjacent waters of Dokdo showing diverse physical properties not only by seasonal variation but also by diverse physical processes. Synechococcus abundances were low in winter and then exponentially increased as water temperature increased up to 20C. Above 20C, the abundances tended to be saturated. On the contrary, Prochlorococcus was undetected or occupied a minor fraction of picocyanobacteria in most seasons. In summer, however, Prochlorococcus belonging to HLII ecotype occupied a significant fraction (up to 7%) of picocyanobacteria. In spring and early summer, the steep increase of Synechococcus abundances were resulted from growth of cold water-adapted Synechococcus belonging to clades I and IV. In summer, diverse Synechococcus clades including warm and pelagic water-favoring clade II tended to replace clades I and IV with maintaining high abundance. The water-column stability as well as temperature were found to be important factors regulating the Synechococcus abundances. Moreover, inflow and mixing of distinct water masses with different origins exerted significant influence on the composition of Synechococcus in the study area. Thus, physical processes as well as natural seasonal variation of environmental factors should be considered to better understand ecology of planktonic organisms around Dokdo.

Seasonal Variations of Physico-Chemical Characteristics and Phytoplanktonic Pigments in Coastal Sea Water from Ullungdo and Dokdo Islands (울릉도와 독도 근해해역의 이ㆍ화학적 특성과 광합성색소의 계절적 변화)

  • 정지안;조은영;차재훈;김미경;김기태
    • Korean Journal of Environmental Biology
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    • v.18 no.4
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    • pp.425-440
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    • 2000
  • The physico-chemical characteristics and the concentrations of chlorophylls of coastal seawater were investigated to know the seasonal variations of biological oceanographic environments in the Islands of Ullungdo(U) and Dokdo(D). The samplings of sea water according to different depths were performed four seasons (May, June, August and November) in five stations along the coast of Ullungdo Island and 3 times (June, August and November) in three stations around the coast of Dokdo Island. The seasonal variations of sea water temperature showed that the formation of thermocline in August was distinct in comparison to the other seasons. The sea water in the surface was influenced by low temperature-high salinity in May and with high temperature-low salinity in the investigated area. The amount of seston was high in May (5.3-15.0mg/l) and was low in August (1.4-4.9mg/l) in ullungdo island. for the nutrients or sea water in Ullungdo Island, the concentrations of nitrate and ammonium were higher than Dokdo Island (nitrate-max. of U in August : 0.10-11.50μg/1, max. of D in August : 2.92-8.10μg/l : ammonium-max. of U in November : 14.18-20.69μg/l, max. of D in June : 0-1.78 μg/l). The high concen-tration of chlorophylls showed on the deeper layer from 30 m to 50 m in August (U 30 m : 0.85μg/l ; D 50m : 1.02 μg/l), while the concentrations of chlorophylls were even in May, June and November in the deeper layer of surface layer. In conclusion, the establishment of thermocline in deeper area of the euphotic layer in August was a trigger far the development of phytoplankton, while the complex physico-chemical system by diverse currents and vertical mixing of sea water in the area induced the even distribution of phytoplankton in both epilimnion and hypolimnion in May, June and November.

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Seasonal distribution of phytoplankton and environmental factors in the offshore waters of Dokdo: Comparison between 2018 and 2019 (독도 연안 식물플랑크톤의 계절적 분포 특성과 환경요인: 2018년과 2019년 비교)

  • Lee, Minji;Kim, Yun-Bae;Kang, Jung Hoon;Park, Chan Hong;Baek, Seung Ho
    • Korean Journal of Environmental Biology
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    • v.38 no.1
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    • pp.47-60
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    • 2020
  • To assess the characteristics of phytoplankton community structures related to environmental factors, seasonal surveys were conducted in the vicinity of Dokdo. In 2019, phytoplankton of four phyla and 69 species were observed. During winter, unidentified nanoflagellates dominated, with an average of 3.19×104 cells L-1. In spring, unidentified nanoflagellates occupied about 50% of the composition and a variety of dinoflagellates appeared. The summer phytoplankton population showed very low abundance. In autumn, various species of Chaetoceros appeared, along with diatoms, such as Bacteriastrum spp., Guinardia striata, and Pseudo-nitzschia spp. In addition, tropical species Amphisolenia sp. and Ornithocercus sp. were observed in both 2018 and 2019. The diversity was high in the summer of 2018 and the winter of 2019 and the characteristics of each index varied. Cluster analysis was divided into four groups according to species and population characteristics regardless of the season. The stratification of spring was particularly weak. In the autumn of 2018, the water mass was stabilized in the same way as in the summer, which is considered a suitable condition for phytoplankton growth. However, in 2019, the water masses were mixed, resulting in a low population. In a phytoplankton comparison, the dominant group showed seasonal differences, except for summer when the population was low, and the difference was most pronounced in autumn. Therefore, the waters surrounding Dokdo have different environmental and ecological characteristics from the East Sea, but the seasonal characteristics of each year are considered to be different depending on the topography, various currents, the island effect, and other factors.

Subsurface Investigation of Dokdo Island using Geophysical Methods (물리탐사기법의 독도 지반조사 적용)

  • Kim, Chang-Ryol;Park, Sam-Gyu;Bang, Eun-Seok;Kim, Bok-Chul
    • Geophysics and Geophysical Exploration
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    • v.11 no.4
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    • pp.335-342
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    • 2008
  • Electrical resistivity and seismic refraction surveys were conducted to investigate geologic structures and geotechnical characteristics of the subsurface, along with rock physical property measurements in Dokdo island. The survey results in Seodo island show that the fault adjacent to the fisherman's shelter is a normal fault and extended towards the NW direction, and that Bedded Lapilli Tuff in the downstream was more severely influenced by weathering and erosion than Trachy Andesite II in the upstream of the survey area. In Dongdo island, Trachy Andesite III and Scoria Bedded Lapilli Tuff were severely weathered and eroded, considered as weathered to soft rock formations, and their weathered zone becomes thicker towards the antiaircraft facility in the NE direction of the survey area. The study results also illustrate that Trachyte and Trachy Andesite are hardest, Massive Tuff Breccia is next, and Stratified Ash Tuff is the most soft rock in Dokdo island.