• Journal of Microbiology
• /
• v.35 no.1
• /
• pp.1-9
• /
• 1997

Distribution of airborne microorganisms was determined with two different types of air samplers, the Anderson cascade sampler and the Aerobioscope sampler, in the vicinity of Taejon. The size distribution of particles carrying bacteria and fungi was concurrently measured. The concentration of detected viable airborne particles was greatly varied. It was observed that the number of microbial particles increased in April and October. The most isze o particles carrying bacteria was larger than 4.7 .mu.m in mean aerodiameter, which made up 69.8% of the total particle fraction. About 63.2% of fungi-carrying particles were smaller than 4.7 .mu.m in aerodiameter. The distribution of particles on Yellow Sand Phenomena days was also analyzed. The number of fine particles having mass median aero-diameter from 1.0 to 10.mu.m increased on Yellow Sand Phenomena days to about 6 times that on normal days and the n umber of colony forming unit (CFU/$\textrm{m}^3$) of airborne bacteria also increased by 4.3 times in April. The reuslts from the Anderson sampler showed that the concentration of bacteria increased greatly on the fraction of fine particles ranging from 0.6 $\mu$m to 4.7 $\mu$m in diameter. Unlike the increase in bacterial floraon Yellow Sand Phenomena days, the fungal concentration slightly decreased and showed a normal size distribution parttern. This study suggests that a long-range transmission of bacteria results form bacteria adsorbing onto the fine particles during the Yellow Sand Phenomena.

• 한국해양학회지
• /
• v.30 no.4
• /
• pp.332-340
• /
• 1995

To study stratigraphy of tidal basin deposits, related unconformity and source of late Holocene tidal sediments in Namyang Bay, west coast of Korea, total 8 vibracore sediments have been analyzed. The uppermost stratigraphic sequence of the late Holocene Namyang intertidal deposit overlies three different stratigraphic sequences (1) oxidized reddish brown muddy deposit (Yongduri Member), (2) oxidized yellow deposit (Kanweoldo Formation) and (3) the pre-Cambrian gneiss complex unconformably. Accordingly, three unconformities between those different sequences are recognized. The Namyang tidal deposits (late Holocene) with several meter thickness are mostly coarsening upward sequence suggesting transgressive phase during a continuous rise of sea level. The tidal deposit vibracored down to 4.5 m in depth contains clastic glauconite sands (2% in average) from 2.5 m to the vibracore bottom. These glauconite sands are considered to be transported to the site of Namyang Bay tidal sedimentation from offshore continental shelf of the Yellow Sea along the course of late Holocene sea-level rise.

• Journal of the korean society of oceanography
• /
• v.35 no.4
• /
• pp.179-191
• /
• 2000

Both acid-leached and residual Pb in surface sediments of the Yellow Sea are analyzed in order to explain the spatial distribution of Pb contents and to determine a major controlling factor of its geographical distribution. Leached and residual Pb contents in surface sediments, which may have a different origin, show mirrored geographical distribution. Sediments with high residual Pb ( ${\sim}$20 ${\mu}$g/g; northeastern sand) contain low leached Pb (6-8 ${\mu}$g/g) while sediments with high leached Pb ( ${\sim}$20 ${\mu}$g/g; central mud) contain low residual Pb. As a result, total Pb shows little variation spatially. The mirrored distribution of both species also leads the grain-size dependence of Pb contents to be unclear although the grain-size dependence of other trace metals (Cr, Co, Ni etc.) has been well reported in this shelf. High leached Pb contents (>15 ${\mu}$g/g) were also observed in sediments off the Changjiang River mouth and off the Kyunggi Bay where they can be interpreted as the results of diagenetic accumulation and anthropogenic pollution, respectively. Residual Pb enriched in sands of the northeastern area might be from K-feldspar, which in turn allows the suggestion that northeastern sands may have originated from coastal erosion of granitic landmass or directly from nearby rivers.

• Journal of Environmental Science International
• /
• v.1 no.1
• /
• pp.77-88
• /
• 1992

Distribution patterns of the chemical species, contained or dissolved in the sediments and porewater, were studied from the submarine environments around Deok-Jeok Island, Yellow Sea. The sediments in the study area are predominantly composed of medium to coarse sands, and consequently of very low organic carbon (0.003%) -0.26%o dry weight sediments). As opposed to the strong enrichment of porewater with nutrients and heavy metals in the ordinarily muddy, organic-rich sediillents, the porewater enrichment is not intense in this sandy, organic-poor sediments: porewater phosphate is enriched to the maximum of only seven (average two) times over that in the bottom water. Concentrations of the heavy metals dissolved in porewater show a bit greater enrichment than the nutrient: Zn shows the lowest enrichment (7 times that of the bottom water) and Mn the highest (450 times that of the bottom water). However, these enrichments of the chemical species in porewater are the natural consequences of decomposition of the organic matter in sediments, and still fall short in the magnitude of those in the muddy, organic-rich sediments. Mining of the sands in the study area may pose a threat to the seawater quality as it causes a large scale porewater discharge to the bottom water. The additional supply of the nutrients by this discharge may develop an eutrophic state and, in consequence, an excessive nitrification of the water column. Since the residence times of the nutrients are much longer than those of the heavy metals, a long-term monitoring of the concentration changes in the porewater nutrients is very important to assess the potential deterioration of the seawater associated with the sand mining in the study area.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.42 no.6
• /
• pp.683-694
• /
• 2009

High-resolution (Chirp and Sparker system) seismic profiles were analyzed to investigate the sedimentary sequence and distribution pattern of the late Holocene deposits in Gyunggi Bay, the Yellow Sea. The bay is located in the western part of Korea, east of the Yellow Sea. The sedimentary sequence divided into three units bounded by erosional bounding surface: (1) acoustically parallel to subparallel reflectors with cross bedding structures (Unit 1); (2) confused inner reflectors and top of unit exposed partially at the seafloor (Unit 2); and (3) approximately parallel reflections and regressive to transgressive incision-fills (Unit 3). On the basis of seafloor morphology, surface bedforms, and subbotom acoustic characters, echo types in the study area were identified following the schemes of Chough et al. (2002); (1) flat seafloor with sharp bottom echoes (echo types 1-1, 1-2 and 1-3; transgressive sediment sheets or relict sands), (2) mounded seafloor with either smooth surface or superposed bedforms (echo types 2-1 and 2-2; tidal ridges), and (3) various-scale eroded seafloor (echo types 3-1 and 3-2; channels). Suspect features of acoustic turbid zones which is related to gas charged sediment are reported.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2003.11a
• /
• pp.648-653
• /
• 2003

Optimized recovery of heavy minerals from the near shore sands of Korean Yellow Sea was investigated using physical processing technologies such as gravity concentration and magnetic separation. The head samples were subjected to the three stages effective separation; Head sample was first treated by a spiral separator to recover rough heavy mineral concentrates, which are contained minerals like ilmenite, zircon and rare earth minerals. Much higher beneficiation processes were subsequently taken by wilfley table and magnetic separation according to their magnetic field responses. Heavy minerals were effectively recovered by wilfley table and subsequent recleaning of heavy minerals by magnetic separations was conducted. Qualitative and relative-quantitative analyses of their constituent elements were doing using XRD and XRF.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2002.10a
• /
• pp.282-283
• /
• 2002

Corbicula (Corbiculina) papyracea (Heude) is fresh water clam which lives on the sands and muds, its size was about 3~25 mm with yellow gray color. Shell width of the clam is thin and smooth and growth lines are marvelous and inside of shell colored pink or pink with red. And the clam reproduces itself through virgin generation (Park et al., 1989), ovoviviparous (Kwon et al., 2001) method. There are reports about Corbicula by Kim and Yoo (2000), Kwon et al. (1987), and Lee et al. (1985) but there aren't many report about C. (C.) papyracea. The aim of this work is to present the dynamics of D.(C.) papyracea from Chungpyeong.

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

• 한국해양학회지
• /
• v.29 no.4
• /
• pp.357-365
• /
• 1994

The sediments on the continental shelf off the west coast (middle part) of Korea are divided into northern sandy deposits and southern muddy sediments, respectively. The sandy sediments consist dominantly of quartz and feldspar grains, representing mature-stage sediment in composition. Further-more, the presence of iron-stained quartz grain and glauconite does indicate that the sediments are similar to the relict sediments on the outer shelf of Yellow Sea and East China Sea. These sandy sediments are interpreted as a basal sands that were deposited during the transgression period due to sea-level rise after to last glacial maximum (LGM). The tidal deposits in the Namyang Bay, the west coast of Korea are divided vertically into the upper layer of muddy sediments and the lower layer of sandy sediments. the upper layer sediments contain abundant rock fragments, and are interpreted as the modern tetragenous sediments. The lower layer sediments, on the other hand, are rich in quartz and feldspar grains, representing high index of sediment maturity ratio. the lower layer sandy deposits show the presence of iron-stained.