• Korean Journal of Environment and Ecology
• /
• v.17 no.3
• /
• pp.295-303
• /
• 2003

The tidal flat area of south and west coast consists of 2.4% of total land area of Korea. About 83% of tidal flat is located at the west coast, and the remaining tidal flat is located at the south coast. This tidal flat is also divided for administrative regions which are Gyeonggi Province(35.1%), Chungnam Province(12.7%) Jeonbuk Province(4.7%), Jeonnam Province(44.0%) and Gyeongnam Province(3.5%). The tidal flat of west coast of Korea is one of the most important stopover site for shorebirds on the East Asia-Australia Flyway. The tidal flat is used for feeding and resting place by migratory shorebirds. Generally, waterbirds including migratory shorebirds are considered as key species to show the superiority of wetland. By the criteria of Lamsar Convention in the basis of waterbird, at least 14 coastal wetlands in Korea have to be internationally important wetlands. The factors to affect the distribution of shorebirds at the certain tidal flat are closely related with 1) the distribution of benthic invertebrates, potential prey of shorebirds 2) the availability of roosting site 3) the size of tidal flat 4) the intensity of human disturbance. In this paper, we summarized the regional status of tidal flat of Korea and its conservation methods related with migratory waterbirds.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.24 no.1
• /
• pp.139-159
• /
• 2019

This survey was conducted from May 2017 to August 2018 as part of the National Marine Ecosystem Surveys sponsored by MOF (Ministry of Oceans and Fisheries) and KOEM (Korea Marine Environment Management Corporation). The survey was conducted at 157 stations including intertidal zones, coastal sand dunes and beaches. A total of 72 species of halophytes were identified and the total vegetated area was $1,813,546m^2$ in coastal waters of Korea. In the west coast region, Suaeda japonica was the dominant species, Phragmites communis in the southern coast, and Carex kobomugi in the east coast. Phragmites communis was the most dominant with $1,136,643m^2$ (62.7%) in the whole surveyed area. The top 11 dominant plants are Phragmites communis, Suaeda japonica, Suaeda maritima, Zoysia sinica, Carex kobomugi, Elymus mollis, Suaeda malacosperma, Phacelurus latifolius, Triglochin maritimum, Carex pumila and Carex scabrifolia, and Phragmites communis and Suaeda japonica accounted for 75.9% of the total vegetated area. The distribution of halophyte on the coast of Korea was determined by the habitat types rather than the climate ranges, and there was a difference in the species diversity and habitat range of the halophyte depending on the habitat diversities within the same area.

• The Journal of the Acoustical Society of Korea
• /
• v.18 no.3E
• /
• pp.9-20
• /
• 1999

To investigate the characteristics of internal waves (IWs) and their effects on acoustic wave propagation, a series of sea experiment were performed in the east coast of Donghae city, Korea in 1997 and 1998 where the water depth varies between 130 and 140 m. Thermistor strings were deployed to measure water temperatures simultaneously at 9 depths. CW source signals with the frequencies of 250,670 and 1000 Hz were received by an array of 15 hydrophones. Through the Wavelet transform analysis, the IWs are characterized as having typical periods of 2-17 min and duration of 1-2 hours. The IWs exist in a group of periods rather than in one period. Underwater acoustic signals also show obvious energy peaks in the periods of less than 12 min. Consistency in the periods of the two physical processes implies that acoustic waves react to the IWs through some mechanisms like mode interference and travel time fluctuation. Based on the thermistor string data, mode arriving structures are analyzed. As thermocline depth varies with time, it may cause travel time difference as much as 4-10 ms between mode 1 and 2 over 10 km range. This travel time difference causes interference among modes and thus fluctuation from range-independent stratified ocean structure. In real situations, however, there exist additional spatial variation of IWs. Model simulations with all modes and simple IWs show clear responses of acoustic signals to the IWs, i.e., fluctuations of amplitude and phase.

• Korean Journal of Environmental Biology
• /
• v.33 no.2
• /
• pp.160-169
• /
• 2015

Three unrecorded species of free-living marine nematodes, belonging to genus Enoplus Dujardin, 1845 collected from rocky intertidal seagrass on the eastern coast of Korea, are described and illustrated. Enoplus taipingensis Zhang and Zhou, 2012 is characterized by longer body size, a series of lateral setae throughout the tail in male, the presence of trumpet-shaped precloacal supplement with well-dilated proximal end, and the presence of spicules with five to eight semicircular plates. Enoplus meridionalis Steiner, 1921 is characterized by the presence of trumpetshaped precloacal supplement with slightly dilated proximal end, paired massive spicules, and tail with two pairs of stout terminal setae. Enoplus mammillatus Timm, 1959 is easily distinguished from the congeners by narrow tubular-shaped precloacal supplement. In this study, we provide detailed morphological features of three Enoplus species by differential interference contrast microscopy and scanning electron microscopy. This is the first report on the species of the genus Enoplus from the Korean waters.

• ALGAE
• /
• v.27 no.4
• /
• pp.259-268
• /
• 2012

The genus Pterosiphonia is composed of 22 species worldwide and four of these species have been reported in the North-East Asia. In Korea, P. pennata originally described from the Mediterranean Sea has been previously recorded from the southern coast as a widespread species. In order to confirm the same species from Korea and Mediterranean, we observed the morphology of Korean Pterosiphonia specimen and analyzed rbcL sequences for inferring phylogenetic relationships among similar congeners. Korean entity was recognized as a new species, Pterosiphonia arenosa sp. nov. The new species is characterized by ecorticate axes with 7-10 pericentral cells, branches formed every two segments, and coalesced with main axis over 1-1.25 axial segments, and tetrasporangia formed in straight series on determinate branches of the upper parts of erect axes. A phylogenetic analysis of rbcL sequences demonstrated that P. arenosa was distinct from P. pennata found in Spain as well as other species. In conclusion, morphological and molecular sequence data indicated that P. arenosa sp. nov. has been previously misidentified as P. pennata in Korea.

• Computers and Concrete
• /
• v.11 no.1
• /
• pp.51-61
• /
• 2013

This paper describes earthquake response of the Arhavi Highway Tunnel its geometrical properties, 3D finite element model and the linear time history analyses under a huge ground motion considering soil-structure interaction. The Arhavi Highway Tunnel is one of the tallest tunnels constructed in the Black Sea region of Turkey as part of the Coast Road Project. The tunnel has two tubes and each of them is about 1000 m tall. In the study, lineartime history analyses of the tunnel are performed applying north-south, east-west and up accelerations components of 1992 Erzincan, Turkey ground motion. In the time history analyses, Rayleigh damping coefficients are calculated using main natural frequency obtained from modal analysis. Element matrices are computed using the Gauss numerical integration technique. The Newmark method is used in the solution of the equation of motion. Because of needed too much memory for the analyses, the first 10 second of the ground motions, which is the most effective duration, is taken into account in calculations. The results obtained 3D finite element model are presented. In addition, the displacement and stress results are observed to be allowable level of the concrete material during the earthquakes.

• Journal of Environmental Science International
• /
• v.15 no.4
• /
• pp.373-378
• /
• 2006

The western coast of South Korea is famous for its large and broad tidal lands. Nevertheless, land reclamation, which has been conducted on a large scale, such as Sihwa embankment construction project has accelerated coastal environmental changes in the embankment inland. For monitoring of environmental change, vegetation change detecting of the embankment inland were carried out and field survey data compared with Landsat TM, ETM+, IKONOS, and EOC satellite remotely sensed data. In order to utilize multi-temporal remotely sensed images effectively, all data set with pixel size were analyzed by same geometric correction method. To detect the tidal land vegetation change, the spectral characteristics and spatial resolution of Landsat TM and ETM+ images were analyzed by SMA(spectral mixture analysis). We obtained the 78.96% classification accuracy and Kappa index 0.2376 using March 2000 Landsat data. The SMA(spectral mixture analysis) results were considered with comparing of vegetation seasonal change detection method.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.51 no.3
• /
• pp.396-404
• /
• 2015

Morotoge shrimp Pandalopsis japonica is caught by pot and others in the eastern coastal waters of Korea. Comparative fishing experiments were carried out in the eastern coast of Korea, using the dome-shaped pots with different five mesh sizes (17.1, 24.8, 35.3, 39.8, and 48.3 mm) in order to estimate the mesh selectivity of the pot for the morotoge shrimp, Pandalopsis japonica. The SELECT (Share Each Length's Catch Total) analysis method was applied to the catch data. The master selection curve of the pot for the shrimp was estimated to be s(R) = exp(15.770R-10.573)/[1+exp(15.770R-10.753)], where R is the ratio of carapace length to mesh size. From the selection curves, the carapace lengths of 50% retention were 11.6, 17.0, 23.9, and 34.1 mm for 17, 25, 35, and 50 mm mesh-size pot, respectively. It means that the pots of larger mesh size allow more shrimp of small size to escape.

• Journal of Korean Society for Atmospheric Environment
• /
• v.15 no.6
• /
• pp.727-738
• /
• 1999

Total 76 aerosol samples were collected at Sungsan in Cheju Inland by high volume air sample for 1 year, from May 1995 to April 1996, and were analyzed for major elements(Na, Mg, Ca, Al, Fe) and trace elements(Mn, Co, Ni, Zn, Cd, Pb, U) by ICP/AES and ICP/MS. This study aims to determine the concentrations of trace metals and their seasonal variations in the atmosphere of Cheju Island, where is the remote area from pollution sources and also is the midway of transport of Asian continental materials into the western North Pacific. The concentrations of Na and Mg contributed by sea-salt aerosols were similar to those in the western part of Cheju island(Kosan) and in the western coast of Korea(Mallipo). They showed the highest value in summer and the lowest in spring and winter. Crustal metals(Al, Fe, Ca, Mn, Co, U) were 2~3 times lower than those of Mallipo. These metals showed the lowest values in summer and the highest in spring. Pollution-derived metals (Zn, Cd and Pb) were 2~4 times lower than those in Malipo. Some elemental ratios in aerosols grouped by three wind directions(north-northwest, east, and south-southwest) such as Fe/Al and Pb/Zn are presented as useful tracers indicating source areas, and their differentiation may be explained by geology and fuel types of source areas.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.44 no.6
• /
• pp.684-688
• /
• 2011

The feeding habits of Paralichthys olivaceus in the Uljin marine ranching area, located on the mid-eastern coast of Korea, were studied from January to November 2009. In total, 381 specimens were collected; fish ranged in size from 15.4 to 59.0 cm in total length. P. olivaceus is a carnivore, mainly consuming other fishes and crustaceans. The prey items of P. olivaceus changed ontogenetically. Small individuals fed on decapod crustaceans while large ones fed heavily on other fishes. The diet of P. olivaceus varied seasonally. Fish comprised the main prey items throughout the year. The stomach contents index (SCI) of each size class increased and the dietary breadth index (DBI) of each size class decreased as individuals grew.