• 한국환경과학회지
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• 제11권6호
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• pp.529-535
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• 2002

Efffcts of physico-chemical factors on the zonation and vertical distribution of benthic microalgal communities in the tidal flats of Youngkwang and Canaiin, Korea, were studied. Concentrations of nutrients were low throughout the study period. A 38 species of benthic microaigae was identified. Most of the algae were pennate diatoms with small size. Cell numbers at silty sediments were higher than sandy sediments, and showed high patchy distribution. Zonal distributions of benthic microalgae showed higher variation from silty sediment than sandy sediments. Benthic microalgae showed vertical migration within the upper few mm of sediment with periodicity closely related to tidal cycles. Maximum cells were observed from 0 mm depth both sandy and silty sediments. Cells of benthic microalgae in the 1 - 2 mm depth decreased after desiccation of sediments. The variation of cells was higher at sandy sediments than silty sediments. Cell numbers of benthic microalgae showed no positive relationships with pH and nutrinets except NH$_4$-N.

• 상하수도학회지
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• 제23권1호
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• pp.97-105
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• 2009

Analysis was done on the particle size distribution of sediments flown into Saemangeum from the Mankyung and Dongjin River. The organic pollutants and heavy metal existing in the sediments were analyzed, which was further used to study the properties of pollution in the sediments according to the particle size distribution. Conclusions shown below were made from these analyses. The particle size distribution showed a big difference between the upriver areas of Mankyung and Dongjin River. Particles under $75{\mu}m$ showed to be around 85% at Dongjin River, while it showed to be around 70% at Mankyung River. This kind of distribution in particle size concluded in greatly affecting the contamination density of the sediments. From the analysis done on the soil type of sediments, deposition in Mankyung River categorized into Silty loam and Sandy loam, where Silty loam covered most of area and deposition in Dongjin River categorized into Sand, Loamy sand, Silty loam, Sandy loam. Considering the weight ratio, the density of contamination of the sediments by particle size at Dongjin and Mankyung River has been analyzed to show that organic pollutants and heavy metals occupy more than 70% of the whole contamination in the range under the particle size of $75{\mu}m$.

• Ocean Science Journal
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• 제43권3호
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• pp.153-160
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• 2008

The distribution of the taxonomical composition and the density of meiobenthos depending on some factors of environment has been studied in bottom sediments of the northern estuary part of Ha Long Bay (Cua Luc estuary). The basic factor of influence on meiobenthic community structure was the granulometric composition of sediment. The greatest taxonomic diversity is noted in the silted sands, lowest - in the silty sediments. The density of meiobenthic community was higher in the silty sediments. Slightly expressed correlation between the density of nematodes and the percentage of silty particles in the sediments is detected (Spearman rank correlation coefficient was $0.49{\pm}0.21$, p=0.035). The nematodes were dominant at all stations. In total, representatives of 66 species of nematodes belonging to 17 families and 52 genera were identified.

• 한국환경생물학회:학술대회논문집
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• 한국환경생물학회 2004년도 학술대회
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• pp.33-33
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• 2004

• 한국해양학회지
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• 제20권1호
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• pp.43-49
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• 1985

서해안 장구만에 발달하는 조간대에서 24개의 표층시료 및 18개의 코아를 채 취하여 퇴적물의 조직 및 퇴적구조를 조사하였다. 이 조간대 지역은 대체로 silt flat, sandy-silt flat, silty-sand flat 으로 구분되며 해안선에서 바다쪽으로 갈수 록 입도가 조립화되는 경향을 보여준다. 코아의 X-ray촬영에 의해 나타나는 퇴적구 조는 bioturbation, current ripple laminae, parallel laminae등이며 지역에 따라 현저 한 차이를 보이고 있다. Bioturbation구조는 1차적으로 형성된 물리적 퇴적구조를 파괴하고 있으며, 만조선 쪽으로 갈수록 그 정도가 증가하고 있다. current ripple laminae 는 bioturbation정도가 비교적 적은 silty-sand, sandy-silt지역에 잘 나타나 며, 몇번의 창조류와 낙조류에 의해 형성된 미세한 사층리를 잘 보여주고 있다. 내 만쪽에 나타나는 parallel laminae는 silt/clay호층의 두께 1mm이하의 층리로이루어 져 있는 반면, 외만쪽에 나타나는 parallel laminae는 sand/silt/호층의 두께 1~5mm 의 층리로 구성되어 있는 것이 특징이다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.177-184
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• 2000

Geotube is a tube made of geotextile and hydraulically filled with dredged soil. This technological method has been widely used in the advanced countries of the world to build the shore protection embankment. The dredged contaminated sediments from the lake, river, and harbor can be pumped into the geotube by using the hydraulic pump. So, environments effects can be minimized and enhanced by using this method. This paper presents a field test result of a geotube in the land reclamation project for the Songdo New City construction site. The dredged silty clay was dredged by the dredging ship and hydraulically pumped into the geotube. The height of geotube was measured at every filling stage and also measured width and diameter of geotube with the elapsed time. The unit weight of soil and undrained shear strength of filled soil in a tube were measured at the various locations and heights of geotube with the elapsed time. Geotube technique can be effectively implemented for the silty clayey soil with using the dredging ship.

• Ocean Systems Engineering
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• 제14권2호
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• pp.101-114
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• 2024

Seafloor sediment mapping is an essential research topic in shallow coastal waters, especially in port development, benthic habitat mapping, and underwater communications. The seafloor sediments can be interpreted by collecting sediment samples directly in the field using a grab sampler or corer. Another method is optical, especially using underwater cameras and videos. Both methods each have weaknesses in terms of area coverage (mechanic) and accurate positioning (optic). The latest technology used to overcome it is the acoustic method (echosounder) with Global Navigation Satellite System (GNSS) Real Time Kinematic (RTK) positioning. Therefore, in this study will propose the classification of seafloor sediments in coastal waters using acoustic method that is Multibeam Echosounder (MBES) multi-frequency with five frequency (200 kHz, 250 kHz, 300 kHz, 350 kHz, and 400 kHz). In this study, the deep neural network (DNN) used the bathymetric multi frequency, bathymetric difference inters frequencies, and bathymetric features from 5 (five) frequencies as input layer and 4 (four) sediment types in 74 (seventy-four) sample sediment as output layer to make a seafloor sediment map. Results of sediment mapping using the DNN method show an overall accuracy of 71.6% (significant) and a kappa coefficient of 0.59 (moderate). The distribution of seafloor sediment in the study area is mainly silt (41.6%), followed by clayey sand (36.6%), sandy silt (14.2%), and silty sand (7.5%).

• 한국수산과학회지
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• 제48권4호
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• pp.555-563
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• 2015

Organic matter and trace metals were investigated in surface sediments of Gomso Bay, where there is dense Manila clam Ruditapes philippinarum farming activity, to evaluate contamination of sediments in intertidal shellfish farming area. We measured mean grain size (Mz), chemical oxygen demand (COD), ignition loss (IL), acid volatile sulfide (AVS), total organic carbon (TOC), and total nitrogen (TN), and trace metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb and Zn) in intertidal and sublittoral sediments. The intertidal sediments were mainly composed of coarser sediments (sand, silty sand, and sandy silt), with Mz values ranging from 2.61 to 4.79 Ø. Mz and the content of organic matter in sediments were lower in the intertidal zone than in the sublittoral zone. The mean metal concentrations in surface sediments decreased in the order Fe > Mn > Zn > Cr > Pb > Cu > As > Cd > Hg. The metal concentrations in surface sediments showed a significant positive correlation with Mz and organic matter content, indicating that metal concentrations in the surface sediments of Gomso Bay are controlled by Mz and organic matter. The concentrations of organic matter and trace metals in the study region were lower than or similar to those in other intertidal zones in western coast and much lower than those reported in other shellfish farming areas in Korea. Our results suggest that intertidal Manila clam farming sediments from Gomso Bay are not contaminated by organic matter and trace metals.

• Journal of the korean society of oceanography
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• 제32권3호
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• pp.120-127
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• 1997

Depositional environment off the Shihwa Dam has been studied to investigate the change of sedimentation process and the pollution. In order to understand how the sediments are distributed, polluted and modified, depositional factors have been analyzed and compared with the previous data. Study area, located off the Shihwa Dam, was surveyed to collect 25 bottom samples and 2 cores in 1996 and echo-sounding in 1997. These sediments were analyzed for the study of the global characteristics of sediment such as grain size and organic matter. Among these samples, the selected twenty surface sediments were analyzed for the comparison with their contents of metallic elements (Al, Mn, Fe, V, Cr, Co, Ni, Cu, Zn, Cd, Pb, As). According to field and lab analysis of sediments, three sedimentological zones have been generally identified around study area; near the dam (sandy Silt), near the dike (Sand) and offshore (silty Sand) zones. Textural parameters show that the content of silt and clay is dominant near the dam excepting the dike zone of LNG Storage Base and offshore (Palmido). The total concentration of Mn, Ni, Fe, Zn and Cd in bulk sediments was increased after the construction of the dam, while the content of Mn and Cr were higher near tidal channel than in the offshore area. Meanwhile, the annual increasing pattern of some heavy metal has appeared in this area. Based on this primary study, modification of the depositional environment may be caused by the construction of the dam and LNG Storage Base. Additionally, environmental evaluation on organic/inorganic factors has been suggested for interpreting environmental changes caused by coastal development in the nearshore such as the Shihwa coastal area.

• 한국습지학회지
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• 제13권2호
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• pp.243-263
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• 2011

시화호 형도 근처 조간대(帶, intertidal zone) 지역 갯벌의 퇴적환경을 알아보기 위해 10개 정점 표층 및 2개 정점 주상퇴적물에 대한 입도, 함수율, 휘발성산화합물(Acid Volatile Sulfide; AVS), 총유기탄소(Total Organic Carbon; TOC) 및 중금속(Al, Fe, Mn, Cu, As, Pb, Zn, Ni, Cd 및 Cr) 항목에 대해 분석 하였다. 표층 퇴적물은 대체로 분급이 불량(분급도, 0.60~2.31${\phi}$)한 sandy Silt, slightly gravelly muddy Sand, silty Sand 및 Sand 등의 퇴적상으로 구분되며, 평균입도는 2.95~6.00${\phi}$로 극조립 실트(Silt)에 해당한다. 표층 퇴적물의 Al 함량은 1.54%, Fe은 1.75%, Cu는 9.1ppm, As는 1.1ppm, Pb은 18.8ppm, Ni은 11.0ppm, Cd은 0.02ppm 그리고 Cr은 30.1ppm으로 측정되었으며, 주상 퇴적물 또한 미국해양대기청(National Oceanic and Atmospheric Administration; NOAA) 기준의 ERL(Effective Range Low, 저서생물에 독성을 보이는 초기 10% 농도)을 초과하지 않았다. 주상퇴적물의 과잉 방사능 납($^{210}Pbex$)의 분포를 통해 퇴적률을 추정한 결과, 급격한 퇴적물의 다량유입에 의해 수직적으로 방사능(activity)이 유사한 값을 나타내고 있어 정확한 퇴적률(apparent sedimentation rate)은 추정할 수 없었다. 그러나 2개 코어 상부 35cm 에서 퇴적물의 급격한 유입 및 환경적 영향등으로 금속 농축계수(Enrichment factors; EF) 계산값은 비교적 높게 나타났다.