• Animal Systematics, Evolution and Diversity
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• v.19 no.1
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• pp.103-109
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• 2003

Presynaptiphilus poraminutus is described as a new species in association with the ophiuroid Ampioplus ancistrotus (H. L. Clark) collected from an intertidal sand beach in the Yellow Sea. The new species is closely related to P. minutus in having the identical leg structure, but may be differentiated from the latter by the larger body, the longer genital double-somite and caudal rami, and the shorter pre-anal semite.

• Korean Journal of Environmental Biology
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• v.36 no.3
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• pp.252-259
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• 2018

A research probing for the unrecorded and taxonomically undescribed indigenous species has been initiated since 2006. Samples were collected from an intertidal zone along the coasts of Korea as well as around the Jeju Island. We have found five unrecorded species of four genera belonging to the order Dinophysiales, Gymnodiniales, Peridiniales, and Prorocentrales. The species are as follows, Sinophysis canaliculata (2017) Bispidodinium angelaceum (2015), Cabra armorica (2016), Prorocentrum bimaculatum (2017), and P. tsawwassenense (2017) (note; The numbers in parenthesis refer to the year in which the species was reported as unrecorded indigenous species by National Institute of Biological Resources, NIBR hereafter).

• Animal Systematics, Evolution and Diversity
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• v.35 no.3
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• pp.114-122
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• 2019

A new species belonging to the genus Cyclopinopsis Smirnov, 1935 (Cyclopinidae) is described from Korea, as the third species of the genus. Specimens were collected by washing the subtidal sediments off Dokdo Island in the East Sea and the intertidal sands at Baegripo beach, Taean Peninsula on the Yellow Sea coast. Cyclopinopsis deformata n. sp. is characteristic and distinguished from its two congeneric species currently recognized, C. curticauda Smirnov, 1935 and C. brasiliensis Herbst, 1955 in having a deformed seta at the outer distal corner of the third exopodal segment of leg 4. The seta is supposed to be deformed from an outer spine on the third exopodal segment of leg 4, which has been known as completely lost in the genus until now. A character comparison table of the three species and a key to species of the genus Cyclopinopsis are provided herein.

• Journal of the Korean earth science society
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• v.21 no.6
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• pp.655-662
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• 2000

According to the development of internet with Web, WBI has greatly influence on the present educational society. However, it is difficutly to design the web of the dynamic motions of graphics or animation using general programming technique based on high or low level language. Recently, Mecromedia Company supported a tool that is called Authoware which is the leading visual rich-media authoring solution for creating Web and online learning applications, to solve the problem easily. In the paper, using the the Authoware we tried to develop a web page about tidal variations due to sea level change and intertidal zone variations using the Authorware 5.1. To do this, we used the ocean survey data of Iho beach and the tidal level data based on Tidal Tables of Cheju harbor. The results showed that the Authorware was very useful to construct the simulation of tidal phenomena on web. Therefore, the Authorware can be applied to the simulation related with animation and dynamic motions for the other WBI objective.

• Journal of The Geomorphological Association of Korea
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• v.25 no.1
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• pp.1-17
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• 2018

The characteristics and burial ages of sand sediments on the Jiduri coast in Daechung-myeon, Ongjin-gun, Incheon were investigated. Daecheong Island is the area where the characteristics of the rocky coast and sand coast are shown. Various studies have been conducted on the Okjukdong sand dune that appears in the north of the island. However, there has been no study on the sandy sedimentary topography of the Jiduri and Moraewul area in the south. The sandy sedimentary terrain of Jiduri is divided into sandy beaches, sand dunes and sand deposits along the slope including climbing dune. Overall, the depth of sandy sediments in Jiduri is not deep. The characteristics of sandy sediments and burial ages were investigated at an elevation of about 23 m above sea level at the back of Jiduli Beach and 46 m above sea level at the ridge line between Jiduri and Moraewol. From the Jiduri coast to the hillside behind, the average grain size decreases and the sorting becomes better as it moves from the intertidal zone to the beach and the foredune. This indicates the selective sand transport by the wind and can be judged by the terrain formed under the current sedimentation environment. The average grain size at the upper part of the section of JD-1 (elevation of about 23m MSL) was $1.6918{\varphi}$ of medium sand. The sorting was $0.4584{\varphi}$, skewness was -1.0491 and kurtosis was -1.2411, respectively. Particularly, the average particle size of the crosssection issomewhat uniform, but the color of the constituent material changes from brown to black. In the case of JD-2 (about 46 m MSL), the mean grain size of the section was $1.7943{\varphi}$, the sorting was 0.4931, the skewness was -1.1163, and the kurtosis was 1.2133. On the other hand, the brown and black layers of JD-1 exhibited a burial age of $0.1{\pm}0.0ka$ and the JD-2 had a burial age of $0.7{\pm}0.0ka$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.276-283
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• 2009

Enrichment in nutrients coming from urban sewage outfalls can lead to eutrophication in coastal areas, which can also change the species composition and community structure of macro algal communities. We investigated the structure of the macro algal community within three rocky shores in order to assess any possible differences in their characteristics. Site 1 was located near Tongyeong city's sewage outfall, Site 2 was located near a public beach area, and Site 3 faced open channel of the Ocean. All three sites were located within the same stretch of the coast, where Site 2 was located between sites 1 and 3. We measured the nutrient concentration in water and the tissue nitrogen content in macro algae samples. Nutrients in the water column surrounding site 1 were high in ammonium ($30.2\pm1.8{\mu}M$), nitrate ($26.2{\pm}0.1{\mu}M$), and phosphate ($2.7{\pm}0.1{\mu}M$) content, and were characterized by low numbers of macroalgal species and species and a low species diversity index. In contrast, site 3 exhibited relatively low nutrient concentration levels and a high number of macroalgal species and a high species diversity index. Comparative analysis showed that the tissue nitrogen content of macroalgae were significantly (P<0.05) affected by the nutrient concentration in the water column. The tissue nitrogen content of green algae within site 1 was higher than the others sites. However, the tissue nitrogen content of brown algae was similar at all three sites. Thus, the tissue nitrogen content of macro algae and the macro algal community structure of intertidal rocky shores were dependent on location and the performance of macroalgal communities was dependent on water quality.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.1
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• pp.39-47
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• 2020

In order to investigate current characteristics at the Gungpyung beach, which is a macrotidal flat, field measurements were carried out in the summer and winter at the intertidal and the subtidal zones. The distribution of residual current at intertidal flat was dominant in the northward direction in the summer and dominant in the northward and southwestern directions in the winter. The direction and speed of the residual current in the winter are highly correlated with the significant wave height, and the turbidity is also highly correlated with the significant wave height. Therefore, in the winter, high sediment rates are suspended by high waves, and sediments are transporting due to the residual current in the southwest direction. On the other hand, it is expected that the northward residual current is predominant due to the small wave in the summer, and sediment transport does not occur largely due to less suspended sediments. In addition, sediment transport in the southern direction is blocked by the dock, which is the artificial structure, and the erosion occurs in the south side of the dock. The erosion pattern in the macrotidal zone of Yellow sea is dominated by seasonal waves, and blocking of sediments by artificial structure is very important.

• Journal of Plant Biology
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• v.29 no.3
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• pp.175-183
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• 1986

Marine algal flora and intertidal vegetation around Samchonpo power plant, south coast of Korea, were investigated at three sites, specially referred to the seasonal variation of the species from April to October, 1982. A total of 84 species were identified; 8 green, 19 brown and 57 red algae. Among three sampling sites investigated, 65 species were collected at the first site located in front of the power plant, 66 at the second site, Namildae beach, and 61 at the third, Sinsudo, respectively. The algal vegetation at the first site was dominated in cover by Sargassum thunbergii and Ulva pertusa in April, Corallina spp. Ulva pertusa in July, and Chondria crassicaulis and Ulva pertusa in October. At the second site, it was dominated in cover by Sargassum thunbergii, Gigartina tenella and Ulva pertusa in April, Sargassum thunbergii and Ulva pertusa in July, and Chondria crassicaulis and Ulva pertusa in October, whereas at the third site Sargassum thunbergii and Ulva pertusa in April, and Chondria crassicaulis in October, respectively. The biomass among three investigated sites showed 2,360 g-fresh wt/$m^2$ on an average; 283 g-dry wt/$m^2$ at the first, 277 g-dry wt/$m^2$ at the second, and 256 g-dry wt/$m^2$ at the third site, respectively.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.3
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• pp.218-226
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• 2016

Field observations were used to study the characteristics and influence of groundwater level fluctuations on vegetation development on the natural beach of a sandy barrier island, in the Nakdong River estuary. The spatial/temporal fluctuations of the groundwater level and the interactions with the external forces (weather, ocean wave and tide) were analyzed. The results indicated that when it rains the groundwater level rises. During summer, when precipitation intensity is greater than 20 mm/hour, it rose rapidly over 20 cm. Subsequently, it fell gradually during periods of no precipitation. Seasonal characteristics indicated that the groundwater level was high during the summer rainy season and tended to fall in the winter dry season. The time-averaged groundwater level, observed from the four observations over 3 years (2012-2014), was about 1.47 m, higher than mean sea level (M.S.L.). It was shown that the average annual groundwater level rises toward the land rather than showing intertidal patterns observation. Differences in the presence or absence of a coastal sand dunes affected the progress of vegetation. In other words, in environments of saltwater intrusion where the groundwater level varies, dependent on the distance from the shoreline and bottom slope, sand dunes can be provided to affect soil conditions and groundwater, so that vegetation can be grown reliably.

• Ocean Systems Engineering
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• v.6 no.1
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• pp.23-60
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• 2016

The major objective of this study was to develop further understanding of 3D nearshore hydrodynamics under a variety of wave and tidal forcing conditions. The main tool used was a comprehensive 3D numerical model - combining the flow module of Delft3D with the WAVE solver of XBeach - of nearshore hydro- and morphodynamics that can simulate flow, sediment transport, and morphological evolution. Surf-swash zone hydrodynamics were modeled using the 3D Navier-Stokes equations, combined with various turbulence models (${\kappa}-{\varepsilon}$, ${\kappa}-L$, ATM and H-LES). Sediment transport and resulting foreshore profile changes were approximated using different sediment transport relations that consider both bed- and suspended-load transport of non-cohesive sediments. The numerical set-up was tested against field data, with good agreement found. Different numerical experiments under a range of bed characteristics and incident wave and tidal conditions were run to test the model's capability to reproduce 3D flow, wave propagation, sediment transport and morphodynamics in the nearshore at the field scale. The results were interpreted according to existing understanding of surf and swash zone processes. Our numerical experiments confirm that the angle between the crest line of the approaching wave and the shoreline defines the direction and strength of the longshore current, while the longshore current velocity varies across the nearshore zone. The model simulates the undertow, hydraulic cell and rip-current patterns generated by radiation stresses and longshore variability in wave heights. Numerical results show that a non-uniform seabed is crucial for generation of rip currents in the nearshore (when bed slope is uniform, rips are not generated). Increasing the wave height increases the peaks of eddy viscosity and TKE (turbulent kinetic energy), while increasing the tidal amplitude reduces these peaks. Wave and tide interaction has most striking effects on the foreshore profile with the formation of the intertidal bar. High values of eddy viscosity, TKE and wave set-up are spread offshore for coarser grain sizes. Beach profile steepness modifies the nearshore circulation pattern, significantly enhancing the vertical component of the flow. The local recirculation within the longshore current in the inshore region causes a transient offshore shift and strengthening of the longshore current. Overall, the analysis shows that, with reasonable hypotheses, it is possible to simulate the nearshore hydrodynamics subjected to oceanic forcing, consistent with existing understanding of this area. Part II of this work presents 3D nearshore morphodynamics induced by the tides and waves.