• Journal of the Korean Geophysical Society
• /
• v.2 no.3
• /
• pp.191-200
• /
• 1999

Analysis of chirp high-resolution seismic profiles from the central Yellow Sea reveals that depositional environments in this area can be divided into three distinctive zones from west to east: (1) subaqueous delta system near the Shandong Peninsula, (2) erosional zone in the central Yellow Sea, and (3) tidal sand ridges and sand waves near the Korean Peninsula. The Shandong subaqueous delta, extending southward from the Shandong Peninsula, changes gradually into prodelta southeastward. The sediments originated from the Yellow River are transported southward along the Chinese coastal area. The erosional zone in the central Yellow Sea contains numerous paleochannels and shows linear erosional features trending northwest-southeast. The erosional zone would be dominated by non-depositional or erosional processes during the Holocene. Tidal sand ridges and sand waves are well developed along the western coast of Korea. The residual sands, which were originally fluvial sediments at the sea-level lowstand, are interpreted as the result of winnowing process during the sea-level rise. Modern sand ridges generally migrates in a northeast-southwestern direction, which coincide with dominant tidal current direction.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.1 no.1
• /
• pp.46-54
• /
• 1996

A study on the concentrations of total suspended matters (TSM) and their distribution pattern was conducted off the west coast of Tae-An Peninsula during the spring season. Especially non-destructive and fine-tuned analysis for the size-distribution of suspended matters was made using SPECTREX instrument. Water masses were characterized by the typical tidal front, with vertically homogenous coastal waters and the strong thermoclines on the offshore area. Concentrations of suspended matters were generally less than 10 mg/l, but the concentrations increased up to 25 mg/l at the bottom waters and mid-depth waters. Mean particle size of the suspended matters were generally 5-6$\mu\textrm{m}$ and 8-10$\mu\textrm{m}$ for the fine-grained suspended matters and the coarse-grained suspended matters, respectively. They are considered to be composed dominantly of detrital materials. On the coastal area, landward side of tidal front, bottom sediments can be easily resuspended by the strong tidal currents, and therefore, deposition of suspended materials are thought to be rather limited. On the offshore area, however, suspended sediments mostly supplied from the northern part of the present study area near Kyunggi Bay are thought to be transported southward and/or southwestward along the mid- depth layer of strong thermocline.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.14 no.3
• /
• pp.619-633
• /
• 1994

A wave deformation model for general purpose combined refraction, diffraction, and breaking is developed in the shallow water. A parabolic approximation equation considered a higher order diffraction term is derived from the previous mild slope equation. A wave energy dissipation term due to bottom friction and breaking is introduced from the turbulence model. The Crank-Nicoloson implicit scheme is used in the numerical calculation, then the solutions are compared with the various hydraulic experiment data in the circular, the elliptic shoal, and the surf zone. The wave height decay in the surf zone is sensitively affected by the incident wave steepness, and the wave height variation around the elliptic shoal is well explained by the non-linear dispersion relation and the wave energy dissipation term. The model is also applied to a field coastal area and reasonable results are obtained.

• ALGAE
• /
• v.27 no.4
• /
• pp.249-258
• /
• 2012

Nongeniculate coralline red algae are a common element of the Brazilian coastal zone, especially associated to coral reefs. During the course of ecological studies at Parque Municipal Marinho do Recife de Fora, two species of non-geniculate Corallinales were the major organisms covering the reef. Analyses of the vegetative and reproductive features of the species were analyzed; indicating that one new species of the genus Lithothamnion is proposed here based on the combination of several features associated with anatomy of the tetrasporangial conceptacles in relation to other species of the genus for which modern accounts are available. This new proposal along with other new species, new combinations and range extension of some species of the genus based in similar features clearly suggest that stability in species delimitation is possible. The second species found Pneophyllum conicum represents a range extension of more than 6,000 km from the Pacific in to the Atlantic Ocean suggesting that some nongeniculate species are widely distributed. The occurrence and abundance of these species supports and emphasizes the need for an extensive taxonomic reassessment of coralline red algae in the context of Brazilian coral reef biodiversity.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.52 no.6
• /
• pp.650-655
• /
• 2019

The age and growth of Muraenesox cinereus collected in the South Sea of Korea by Danish seine and coastal Long-line fisheries were determined from right sagittal otoliths between May 2018 and April 2019. Otoliths of 353 fish were observed under reflected light, and the edges of the opaque zone were considered to be the otolith ring. Monthly changes in the marginal index indicated that rings (opaque zones) were formed once a year from June to July. The estimated von Bertalanffy growth equation with growth parameters estimated from non-linear regression were L_t=138.37 (1-e^{-0.18(t+0.79)}) for females and L_t=99.00 (1-e^{-0.13(t+3.99)}) for males. The oldest female M. cinereus was 12 years old, and the oldest male was 8 years old.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.24 no.2
• /
• pp.128-137
• /
• 2012

This paper deals with the local scour around a pipeline exposed to combined waves and current in the shallow water zone. To investigate the characteristics of the scour around a pipeline on the sea bed, experiments were performed according to the various pipe diameters, wave periods, wave heights, and current velocities. Wave generator and current generator were used for the experiments. Two current directions were used ; co-direction and counter direction to the waves. With the experimental results, the correlations between the scour depths and non-dimensional parameters such as Keulegan-Carpenter number(KC), Froude number(Fr), Ursell number(Ur) and velocity ratio were analysed. The relative scour depths were found obviously to be dominated by the wave component when the velocity ratio function approaches zero and those are gorverned by the current component when the velocity ratio approaches unity. Velocity ratio function was approved to be a proper parameter which is able to express the change of the scour in the combined wave and current zone. Also considering the orbital velocity and the current velocity into Fr numer and KC number respectively, scour depths show more favorable correlationship with the parameters.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.6
• /
• pp.708-722
• /
• 2016

Land-Ocean Interactions in the Coastal Zone (LOICZ) models for nutrient budgets were used to estimate the seasonal capacity of the Youngsan Estuary and Youngam-Geumho Estuary to sink and/or supply nutrients such as dissolved inorganic phosphorus (DIP) and nitrogen (DIN) to provide an understanding of the behavior of the coupled biogeochemical cycles of phosphorus and nitrogen in the estuaries (Youngsan Estuary, Youngam-Geumho Estuary) near Mokpo Harbor. During non-stratified periods (May, September, and November, 2008), simple three-box models were applied in each sub-region of the system, while a two-layer box model was applied during on-site observation of stratification development (July, 2008). The resulting mass-balance calculation indicated that even after large discharges from artificial lakes (in May and July), DIP influxes due to a mixing exchange ($V_{X-3}$, or $V_{deep}$) were more than terrigenous loads, indicating the backward transportation of nutrients from a marine source. The model results also indicated that for nutrient loads (DIP and DIN fluxes) in September, an extreme congestion of nutrients occurred around the mouths (sub-region III of the model) of the estuaries, possibly due to an imbalance in physical circulations between the estuaries and offshore locations. In November, the Youngam-Geumho Estuary, into which freshwater was discharged from artificial lakes (Youngam and Geumho Lake), showed nutrient enrichment in the water column, but the Youngsan Estuary showed nutrient depletion. In conclusion, to efficiently control water quality in the estuaries near Mokpo Harbor, integrated environmental management programs should be implemented. I.e., the reduction of nutrient loads from land basins as well as the deposit of nutrient loads into adjacent coastal lines.

• Korean Journal of Ichthyology
• /
• v.28 no.1
• /
• pp.28-34
• /
• 2016

The anatomy and histology of the olfactory organ in Favonigobius gymnauchen was investigated using a stereo microscopy, light microscopy and scanning electron microscopy. The paired olfactory organs in the dorsal snout are set in between the upper lip and the eyes. These organs are composed of two openings (anterior nostril with a tubular structure and posterior nostril), a single olfactory cavity, two nasal sac (ethmoidal and lacrimal sacs), olfactory nerve and olfactory bulb. The distributional pattern of the sensory epithelium is a only one type (continuous type). This epithelium is made up of the receptor cell, supporting cell and basal cell. The receptor cell has a only one type (ciliated receptor cell with 3~4 cilia). The non-sensory epithelium is built of the stratified epithelial cells and has mucous openings on the surface. Such an olfactory organ in F. gymnauchen may be considered to reflect its ecological habitat as a shallow water or tidal pool in the coastal zone.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.1B
• /
• pp.99-106
• /
• 2006

Due to both global warming and constructions of seadike/seawalls, continuously or abruptly rising tendencies of extreme high water levels have been detected at Kunsan and Mokpo harbors. This paper deals firstly with the separation of each effect, namely global warming effect and construction effect, on increases of water level quantitatively by a linear regression method. And then, it can be explained why and how the extreme high water levels had been risen just after constructions at both harbors. A numerical simulation of $M_2$ tidal constituent at Mokpo coastal zone shows that the tidal amplification by constructions is mainly due to the extinguishment of TCE at Mokpogu. The tidal flat effect makes the amplification more deepen at spring tide or extreme high tide, which results in the increase of inundation risk at Mokpo harbor. A frequency analysis method is applied, which is shown to be effective at such a site of having non-homogeneous tidal data due to constructions as Mokpo harbor.

• The Korean Journal of Quaternary Research
• /
• v.17 no.2
• /
• pp.17-23
• /
• 2003

In Korea terrestrial fluvial sequences can be used as pedological and sedimentological markers indicating a millenium-scale environmental and climatic changes imprinted in fluvial sub-environments, which in turn are represented by the cyclicity of fluvial sands, backswamp organic muds, and flooding muds intercalations of frostcracked or dessicated brown paleosols. Post LGM and Holocene fluvial and alluvial sedimentary sequences of Korea are formed in such landscapes of coastal, floodplain, backswamp and hillslope areas. Among them, the most outstanding depositional sequences are fluvial gravels, sands and organic mud deposits in coastal, fluvial, or alluvial wetlands. The aim of this study is to explain the sedimentary sequences and palynofloral zones since the last 15,000years, on the basis of organic muds layers intercalated in fluvial sand deposits. Jangheung-ri site of Nam river, Soro-ri site of Miho river, Youngsan rivermouth site in Muan, Oksan-ri site of Hampyeong and Sanggap-ri site of Gochang are illustrated to interpret their sedimentary facies, radiocarbon datings, and palynofloral zonation. Up to the Middle to Late Last Glacial(up to 30-35Ka), old river-bed, flooding, and backswamp sequences contain such arboreal pollens as Pinus, Abies, and Picea, and rich in non-arboreal pollens like Cyperaceae, Gramineae, Ranunculaceae, and Compositae. During the LGM and post-LGM periods until Younger Dryas, vegetation has changes from the sub-alpine conifer forest(up to about 17-11Ka), through the conifer and broad-leaved deciduous forest, or mixed forest (formed during 16,680-13,010yrB.P), to the deciduous and broad-leaved forest (older than 9,500yrB.P). In the Earliest Holocene flooding deposits, fragments of plant roots are abundant and subjected to intensive pedogenic processes. During Holocene, three arboreal pollen zones are identified in the ascending order of strata； Pinus-Colyus zone(mixed conifer and deciduous broad-leaved forest, about up to 10Ka), Alnus-Quercus forest (the cool temperate deciduous broad-leaved forest, about 10Ka-2Ka), and Pinus forest (the conifer forest, about after 2Ka), as examplified in Soro-ri site of Cheonwon county. The palynological zonations of Soro-ri, Oksan-ri, Sanggap-ri, Youngsan estuary, and Gimhae fluvial plain have been recognized as a provisional correlation tool, and zonations based on fluvial backswamp and flooding deposits shows a similar result with those of previous researchers.