• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2005년도 춘계 학술발표회 논문집
• /
• pp.1241-1244
• /
• 2005

In this case study, the field investigation work on soft soils like a reclamation area with dredged-clay or intertidal mud flat which has not enough strength to resist the load of surveying machines, the amphibious barge(modified AMFIROL) which travels on land and water was adopted to the field investigation work. Despite of slight increase of cost, it was found that the adoption of amphibious barge in field investigation could improve the quality of test results and avoid the waste of time and some effort.

• ALGAE
• /
• 제21권1호
• /
• pp.11-13
• /
• 2006

In this work we report the occurrence of Scytosiphon gracilis Kogame (Scytosiphonaceae, Phaeophyceae) on the Pacific coast of Mexico. This is the first report of S. gracilis outside its previously known distribution in the western North Pacific (Korea and Japan). The identification was based on a morphological revision and a comparison of the plastid-encoded RuBisCO spacer sequences determined for Korean and Mexican algal material. Thalli were collected from the intertidal zone of Saldamando Beach, Baja California, in January 2003. The vegetative structure, as well as habitat and geographic distribution of the species are described. Reproductive structures were not found in our specimens. The poor presence/absence of S. gracilis in previous floristic studies of the area could be due to its small size and low frequency.

• ALGAE
• /
• 제18권3호
• /
• pp.225-232
• /
• 2003

Species composition, community structure and biodiversity of marine benthic community were studied in the rocky shore of Dongbaekseom, Busan. A total of 82 species of marine algae including 4 Cyanophyta, 11 Chlorophyta, 20 Phaeophyta and 47 Rhodophyta are listed. The dominant algal species were Ulva pertusa, Chondria crassicaulis, Corallina spp. and Melobesioidean algae. Sargassum thunbergii, Chondracanthus intermedia, Gelidium divaricatum and Ralfsia verrucosa were subdominant in cases of different seasons and vertical layers. Chthamalus challengeri, Littorina brevicula and Mytilus edulis were dominant zoobenthic species upper-middle layer of the intertidal zone. The community structure of this area seemed to be controlled by spatial competition with benthic marine algae. The species diversity indices estimated from different sources were quite different. Indices from coverage were 1.87, 3.98 from frequency, 2.26 from the average of total frequency and coverage and 2.15 from importance value. The similarity indices on the present study showed decreasing trends comparing to the previous benthic algal composition researches.

• ALGAE
• /
• 제20권1호
• /
• pp.53-59
• /
• 2005

The objective of this study was to clarify marine algal flora and community structure of 16 uninhabited islands in Sinangun area, south western coast of Korea. As a result, a total of 63 species - 11 greens, 16 browns and 36 reds - was identified. The functional groups of marine algal species were filamentous 14.3%, foliose 20.5%, corticated 45.3%, leathery 13.7%, and articulated calcareous algae 6.2%. The (R+C)/P value was calculated as 2.9 showed temperate flora. The result of DCA showed that 16 uninhabitated islands tend to be distributed eastern and western parts. The dominant species was Ulva pertusa, while the subdominats were Gelidium divaricatum, Myelophycus simplex. The vertical distribution pattern of intertidal marine algae represented three distinct zones; Gloiopeltis furcata, Myelophycus simplex, Gelidium divaricatum - Ulva pertusa, Enteromorpha spp., Ishige okamurae - Ulva pertusa, Sargassum thunbergii, Symphyocladia latiuscula.

• 한국패류학회지
• /
• 제20권2호
• /
• pp.135-140
• /
• 2004

Twenty five marine molluscan species were added to the malacofuana of Dokdo Island, Korea based on the samples collected from inter- and subtidal rocky shore of the island on April and November 2004. As a result, seventy five marine molluscan spacies were recorded from Dokdo Island hitherto.

• 한국어업기술학회:학술대회논문집
• /
• 한국어업기술학회 2000년도 춘계수산관련학회 공동학술대회발표요지집
• /
• pp.375-376
• /
• 2000

Sex ratio of a population is a key factor to determine reproductive rate of the population. If the population has skewed sex ratio to the male, the population size may decline gradually at an area which it inhabits, and, furthermore, if a species plays an ecologically important role in its community (e.g., a keystone species in Paine, 1966), its potential reproductive rate will be to form a characterized community because community structure is strongly influenced by the abundance of the ecologically important species (Hughes, 1986). A number of workers (e.g., Bryan et al., 1986 in Nucella lapillus; Spence et al., 1990 in Thais haemastoma) suggested that high frequency and/or late stage of imposex might affect the female mortality and normal reproduction adversely. Consequently, the imposex could affect sex ratio of natural population of some neogastropod including thaisid species. (omitted)

• Animal cells and systems
• /
• 제11권1호
• /
• pp.55-60
• /
• 2007

Four new species, Semitaspongia jejuensis, Scalarispongia regularis, S. nigra and Dysidea violata are described from Jejudo, Korea. They were collected from 15 m depth by SCUBA diving and from intertidal area by hand. Semitaspongia jejuensis n. sp. is easily distinguished from other Semitaspongia species in growth form, conules, colour, skeletal structure, diameter of fibre and habitat. Scalarispongia regularis n. sp. is very close to S. scalaris (Schmidt, 1862) in skeletal structure, but S. scalaris has longer conules, larger meshes, longer distance between primary fibres, and highly developed subdermal canal system. Scalarispongia nigra n. sp. is very close to S. regularis in skeletal structure but can be easily distinguished by its black colour of external surface and growth form. Dysidea violata n. sp. is similar with D. ethria (Laubenfels, 1936) in sponge appearance, but D. etheria is clearly defined by its blue colour and thickness of fibre.

• Journal of Species Research
• /
• 제12권1호
• /
• pp.27-37
• /
• 2023

Kushia zosteraphila Harris V.A. & Iwasaki, 1996 is newly collected and described from macroalgae in the intertidal region of Gijang-gun, along the southeastern coastal region of Korea. Kushia zosteraphila can be distinguished from congeners by following morphological characteristics: the length of the first dorsal seta similar with the second dorsal seta of female P5, the length to width ratio of the female caudal ramus, and the presence of a conspicuous comb on the accessory lobe of the male antennule. Although there are some minor discrepancies, the main diagnostic characteristics of the specimen from the study area are well-matched with the original description. We herein provide detailed morphological descriptions and illustrations of this species. According to a survey of the location of the reported porcellidiid species in Korea, this specimen is the second record in Korean waters of the genus Kushia. A key to species of the family Porcellidiidae in Korea is provided. A partial sequence of the mitochondrial COI gene was obtained and provided as a DNA barcode for this species.

• 한국수산과학회지
• /
• 제50권3호
• /
• pp.319-325
• /
• 2017

Marine algal flora and community structures were examined seasonally at three sites around the Shingori Nuclear Power Plant, Korea from February to November 2016. A total of 76 species were identified, including 9 green, 14 brown and 53 red algae. The greatest number of species occurred at Daesongri (51 species) followed by Sinamri (43 species) and at the discharge area (38 species) during the study period. Of the 76 seaweeds, 59 annuals and 17 warm tolerant species were recorded. Annual average biomass in dry weight varied from $168.02g/m^2$ at the discharge area to $222.53g/m^2$ at Sinamri. The coarsely branched form was the dominant functional form of seaweeds at the three sites. Seaweed community structures at the discharge site were distinguishable by decreasing species richness, biomass, species diversity index, richness index, and evenness index. The ratio of warm tolerance species and the dominance index values were remarkably higher at the discharge than those at the other sites.

• ALGAE
• /
• 제35권1호
• /
• pp.79-89
• /
• 2020

Pythium species are ubiquitous organisms known to be pathogens to terrestrial plants and marine algae. While several Pythium species (hereafter, Pythium) are described as pathogens to marine red algae, little is known about the pathogenicity of Pythium on marine green algae. A strain of a Pythium was isolated from a taxonomically unresolved filamentous Ulva collected in an intertidal area of Oslo fjord. Its pathogenicity to a euryhaline Ulva intestinalis collected in the same area was subsequently tested under salinities of 0, 15, and 30 parts per thousand (ppt). The Pythium isolate readily infected U. intestinalis and decimated the filaments at 0 ppt. Mycelium survived on U. intestinalis filaments for at least 2 weeks at 15 and 30 ppt, but the infection did not progress. Sporulation was not observed in the infected algal filaments at any salinity. Conversely, Pythium sporulated on infected grass pieces at 0, 15, and 30 ppt. High salinity retarded sporulation, but did not prevent it. Our Pythium isolate produced filamentous non-inflated sporangia. The sexual stage was never observed and phylogenetic analysis using internal transcribed spacer suggest this isolate belongs to the clade B2. We conclude that the Pythium found in the Oslo fjord was a pathogen of U. intestinalis under low salinity.