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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
The Korean Society of Oceanography
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Volume & Issues
Volume 2, Issue 2 - Oct 1997
Volume 2, Issue 1 - Mar 1997
Selecting the target year
500-days Continuous Observation of Nutrients, Chlorophyll Suspended Solid and Salinity in the Keum Estuary, Korea
Lee, Yong-Hyuk ; Yang, Jae-Sam ;
The Sea, volume 2, issue 1, 1997, Pages 1~7
We have monitored nutrients, chlorophyll, suspended solids, and salinity in the Keum Estuary to understand the temporal fluctuation of oceanographic parameters and to illustrate any variation due to the gate operation of the Keum River Dike from June, 1995 to September, 1996, approximately for 500 days. Tidal range is used as the key factor to explain the fluctuations and atmospheric parameters such as air temperature, wind velocity and rainfall are also used supplementally. The fresh water discharge was selected as another major impact on the estuarine environment due to the gate operation of the Keum Dike. In addition, daily variation by tidal cycle was investigated twice in April and July, 1996. In diurnal variation, salinity was positively correlated with tidal elevation, whereas negatively correlated with nutrients. Relatively high suspended solid and chlorophyll contents were found in the period between high and low tide. In 500 days continuous observations, salinity was negatively correlated with the volume of fresh-water discharge, but positively correlated with nutrients. A major chlorophyll bloom occurred in spring. A similar pattern of variation was observed between suspended solid and the neap-spring tidal cycle. In comparison with the data of the Keurn Estuary before the gate operation of the Keum River dike, fresh-water discharge predominated other environmental factors during the rainy season. In addition, the velocity of tidal current and the concentration of suspended solid were decreased, while nutrients and chlorophyll contents were increased.
High-Resolution Seismic Characteristics of the Holocene Mud Deposits in the Southeast Innershelf, Korea
Choi, Dpng-Lim ; Oh, Jae-Kyung ; Lee, Chi-Won ; Woo, Han-Jun ;
The Sea, volume 2, issue 1, 1997, Pages 8~13
The Holocene mud deposits in the southeastern innershelf of the Korean Peninsula were studied using the shallow seismic reflection profiles coupled with sediment sampling. The Holocene mud deposits are developed as a belt in the innershelf area from the mouth of the Nakdong River to off Pohang along the coastline. The surficial sediments in the study area gradually become finer and well sorted from south to north. The seismic facies in the Holocene sequence change northward from parallel reflectors in the mouth of the Nakdong River and northeastward prograding reflectors in the southern part off Ulsan to transparent layer in the nearshore off Ulsan to Pohang. The regional difference of seismic facies indicates that the Holocene sediment characters are varied with localities. By combining the surficial sediments properties with seismic facies patterns, the suspended sediments mostly supplied from the Nakdong River may be transported northward along the shore by the north-flowing Tsushima warm current. The Holocene mud sequence overlying the ravinement surface which is produced by erosion of underlying sediments during a rapid transgression can be interpreted as the highstand system tracts probably formed during the highstand of sea level similar to the present-day sea level.
Benthic Foraminiferal Communities of Surface Sediments in the Southwestern Continental Shelf of the East Sea, Korea
Woo, Han-Jun ; Oh, Jae-Kyung ; Kim, Hyo-Young ; Choi, Dong-Lim ; Lee, Chi-Won ;
The Sea, volume 2, issue 1, 1997, Pages 14~20
The southwestern continental shelf of the East Sea, Korea developed mud deposits as a belt in the inner shelf area from Pusan to Pohang. The general surface sediments consist of very poorly to poorly sorted muddy sediment. The differences of physical, geological and geomorphic conditions in the study area may control and produce distinctive foraminiferal populations. To establish a baseline of environment for the muddy sediments in the southwestern continental shelf of the East Sea, 17 stations were sampled and proved to contain 45 species of living benthic foraminifera. Analysis of the foraminiferal populations in cluster analysis recognized to five habitat zones. These habitat zones contain distinctive cooccurrences of the entire occurring species. Foraminiferal community composition appeared to be closely interrelated of water masses, depths, nutrients and sediment characters.
Growth and Production of Sinonovacula constricta (Bivalvia) from the Hwaseong Tidal Flat in the Namyang Bay, Korea
Koh, Chul-Hwan ; Yang, Mee-Ra ; Chang, Won-Keun ;
The Sea, volume 2, issue 1, 1997, Pages 21~30
The present study reports the density, growth and production of a razor clam, Sinollovacula constricta, which is known to be one of the important fishreies catches from the Korean tidal flat. The annual yield reached to about 6,000 metric tons per year till 1994. The study was conducted on the Hwaseong tidal flat located on the central west coast, 40 kilometers south-west from Seoul. The annual yield of the razor clam in this area reached to about 50% of the total catch from the whole Korean coast. Samples were colleted monthly at 14 occasions from May 1992 to August 1993. Density of S. constricta ranged from 92~165 individuals per square meter during the study period. General trend of decreasing density was observed when the animal became older, but an exception was the year class of 1991 whose density was lower than that of 1990. The size of the shell was clearly separated into two classes during fall and winter (from September to February), however, the maximum frequency of the length of small size classes moved to right after February. It indicates a fast growth of young clams from spring to summer. Fast growth of the shell could also be examined by the growth curve. The shell growth of the whole life span was described by the von Bertalanffy equation of
. The growth in flesh dry weight was well fitted to the Gompertz growth model with the equation,
. The clam lost about 30% of the body weight during spawning in August. The annual production calculated based on the data from September 1992 to August 1993 amounted to 150 g
which was 2~50 fold higher than those of other bivalves occurred in Korea. This estimate was patitioned by each year classes; 87.5 by 1992, 53.4 by 1991, 59.0 by 1990 and -30.0 g
by 1989 year class.
Distribution Patterns of the Benthic Macrofaunal Community in the Coastal Area of Inchon, Korea
Koh, Byoung-Seol ; Lee, Jae-Hac ; Hong, Jae-Sang ;
The Sea, volume 2, issue 1, 1997, Pages 31~41
This study was carried out to investigate the composition and the distribution of the benthic community in the coastal area of Inchon seasonally from May 1994 to February 1995, and to estimate the environmental factors that effect the temporal and the spatial changes of benthic species composition. In the present study, 231 species were collected with the average density of 455 ind./
. The dominant species were Heteromastus sp., Sternaspis scutata, Chaetozone setosa, Mediomastus sp., Glycinde sp., Glycera sp. and Nephtys oligobranchia, which are in the polychaete group; abundance of these species showed seasonal and spatial variations. The study area was divided into 4 regions by cluster analysis such as outside area of Palmido (I), main channel region and adjacent are of Shihwa sea wall (II), north-eastern area of Youngjongdo (III), and the Inchon harbor and the mouth area of Sorae harbor (IV). The particle size of sediment which generally influences the distribution of the benthic community, the differences of the concentration of heavy metals, and of the dissolved oxygen, the increase of the proportion of polychaetes and molluscs, the absence of the crustacean phoxocephalids, and the increase of the abundance of pollution indicator species, indicated that the environment of the areas have been degrading gradually from Group I to Group IV.
The faunal composition of meiobenthic community in the deep-sea sediment, northeastern Pacific Ocean
Kim, Dong-Sung ;
The Sea, volume 2, issue 1, 1997, Pages 42~47
This study was carried out to investigate the faunal composition and distribution pattern of meiobenthic community in the deep sea sediments of northeastern Pacific Ocean. Faunal samples were collected at 10 stations using a multiple corer and a spade type box corer during May 1996. A total of 18 meiofaunal groups were found, and Sarcomastigophora was the most dominant group which accounted for 35.8% of total meiofaunal abundance. Nematoda (30.8%), Nauplius larvae of Crustacea (11.9%), Ciliophora (6.8%) and Harpacticoida (3.0%) which were also important components of the meiofaunal community. All of these five faunal groups comprised more than 90% of total meiofauna. The highest density of 195 ind./10
was found at St. 4 (4960 m water depth), but the lowest one, 85 ind./10
at St. 1 (4969 m water depth). The overall mean density of meiofauna was estimated as
. The abundance of meiofauna showed a slow decreasing trend along the water depth. The highest density was observed in the upper 1 cm and density decreased drastically with increasing depth from the surface.