• Korean Journal of Environmental Biology
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• v.40 no.2
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• pp.125-137
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• 2022

To assess the characteristics of meiofaunal community fluctuations related to environmental factors, seasonal surveys were conducted in the subtidal zone of Hallyeohaesang National Park. The average depth of the study area was about 20 m, and the average water temperature at the bottom was low in winter(11.33℃) and high in summer(17.95℃). The sedimentary particles mainly comprised silt and clay at most stations. The abundance of meiofauna ranged from 81.7 to 1,296.5 Inds. 10 cm^-2, and the average abundance was 589.3 Inds. 10 cm^-2. The average abundance of meiofauna in each season was the lowest at 416.5 Inds. 10cm^-2 in winter and the highest at 704.5Inds.10 cm^-2 in spring. The dominant taxa were nematodes (about 92%) and harpacticoids (about 5%). In the cluster analysis of meiofaunal communities, they were divided into four significant groups. The largest group mainly contained spring and summer samples, and contained stations with a high nematode density of over 500 Inds. 10 cm^-2 and harpacticoids below 50 Inds. 10 cm^-2 with a high composition ratio of nematodes. In the cluster analysis, no regional division was found between the stations, and it was thought to be divided by the seasons with high abundance according to seasonal variation and the composition ratio of nematodes and harpacticoids. In the Spearman rank correlation analysis, the density of total meiofauna and the most dominant taxa, nematodes, was not significantly related to environmental factors. However, the density of harpacticoids had a significant positive correlation with water depth and a negative correlation with sediment particle size.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.448-448
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• 2001

담수가 유입되는 하구역에서 저서동물의 공간 분포 특성을 파악하기 위하여 서남해역에 위치한 법성포항 인근의 와탄천 해역을 조사장소로 선정한 다음, 하구역 입구에서 염분 구배에 따라10개 정점을 설정하였다. 저서동물의 채집을 위해 1998년 5월부터 1999년 1월까지 van Veen grab (0.1$m^2$)을 사용하여 각 정점당 3회씩 퇴적물을 채집하였다. 조사 기간 동안 총 114종이 출현하였으며, 이 가운데 다모류가 44종(전체 출현종수의 39%), 갑각류가 34종(30%), 그리고 연체동물이 24종 (21%)을 차지하였다. (중략)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.2
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• pp.217-225
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• 1998

This study was performed to compare the effects of a fish cage on the structure of meiobenthic communities at two locations during May, 1996. The number of meiofaunal taxa at the existing cage site and control site was 15 and 26, respectively. Nematoda was the most dominant group of meiobenthos. Nematoda and Sarcomastigophora comprised more than $90\%$ of total meiofauna at both sites. The total density of control site was 7,702 inds./$10\;cm^{2}$ which is 10 times more than that of fish cage site. The density was highest in the upper 1 cm and decreased with sediment depth. The nematodes/harpacticoid copepods ratio as an index of pollution monitoring for benthic ecosystem at fish cage site was two times higher than at control site. Kinorhyncha known to be sensitive to pollution stress was not found at fish cage site.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.1-9
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• 2022

The effect of sediments in a waste dumping area on marine organisms was evaluated using sediment toxicity tests with a benthic amphipod (Monocorophium acherusicum) and bioluminescent bacterium (Vibrio fischeri) in accordance with the Korean Standard Method for Marine Wastes (KSMMW). Nine sites in the East Sea-Byeong, East Sea-Jeong, and Yellow Sea-Byeong areas were sampled from 2016 to 2019. The test results showed that the relative average survival rate (benthic amphipods) and relative luminescence inhibition rate (luminescent bacteria) were below 30%, which were judged to be "non-toxic." However, in the t-test, a total of 12 benthic amphipod samples (6, 1, 1, and 4 in 2016, 2017, 2018, and 2019, respectively) were significantly different (p<0.05) from the control samples. To identify the source of toxicity on benthic amphipods, a simple linear regression analysis was performed between the levels of eight heavy metals (Cr, As, Ni, Cd, Cu, Pb, Zn, and Hg) in sediments and the relative average survival rate. The results indicated that Cr had the highest contribution to the toxicity of benthic amphipods (p = 0.000, R2 = 0.355). In addition, Cr was detected at the highest concentration at the DB-85 station and exceeded the Marine Environment Standards every year. Although the sediments were determined as "not toxic" according to the ecotoxicity criteria of the KSMMW, the results of the statistical significance tests and toxicity identification evaluation indicated that the toxic effect was not acceptable. Therefore, revising the criteria for determining the toxic effect by deriving a reference value through quantitative risk assessment using species sensitivity distribution curves is necessary in the future.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.3
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• pp.330-342
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• 1998

Benthic environmental parameters were analysed at 40 stations during the period from April 1995 to February 1996. such as water temperature, salinity, and dissolved oxygen (DO)-concentration in the surface and bottom water layers, grain size, chemical oxygen demand (COD), ignition loss, particulate organic carbon (POC) in the sediment of Youngsan River estuary. The water temperature ranged from 4.1 to $29.8^{\circ}C$ in the surface and 4.0 to $20.7^{\circ}C$ in the bottom layers. Salinity ranged from 15.1 to $33.6\%_{\circ}$ in the surface and 31.5 to $33.2\%_{\circ}$ in the bottom layer. The salinity in the outer pan of the study area was higher than that of inner area from autumn to spring, whereas they remained lower in summer. Dissolved oxygen concentration ranged from 5,1 to 11.2 $mg/\ell$ in the surface, and 0.79 to 10,2 $mg/{\ell}$ in the bottom layers. Hypoxic condition ($\le2.0mg/\ell$) was developed in the bottom water layer from Youngsan dike to Mokpo Harhour in summer due to the summer stratification. The surface sediment type was silty clay with a mean grain size of $9.12{\pm}0.45\phi$. The range of COD was from 6.15 to $15.49mgO_2/g$ with a mean of $10.59{\pm}12.64mgO_2/g$. The COD in the inner stations was relatively higher than that of outer stations, and decreased toward the outer part of the study area. Ignition loss (IL) ranged from 3.35 to $15.45\%$ with a mean of $5.96{\pm}1.91\%$. Principal component analysis was carried out from the following five environmental parameters: water temperature, dissolved oxygen in the bottom layer and mean grain size, clay content and COD in the sediment. The forty stations in the study area were classified into three stational groups. Group I was located in the inner part of the estuary characterised by relatively low surface salinity and bottom water temperature, fine sedimemt texture, high organic matter and low dissolved oxygen concentration during the summer. Meanwhile, Group III showing relatively high bottom salinity and water temperature was located in the outer part of the estuary characterising coarse sediment and low organic content in sediment. Group II was between Group I and Group III. The division of the areal groups had high correlations to the DO in the bottom layer and clay content in the sediment.

• 한국해양학회지
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• v.9 no.2
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• pp.31-38
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• 1974

Concentration of heavy metals in the sediments from the sea off Jinhae and Masan have been studied. Concentration of the elements varied among the stations as the following: 0.32-0.76% Fe, 0.01-0.06% Mn, 29-120ppm Zn, 1-16ppm Co, 2-38 ppm Ni, 2.5-12.4ppm Pb and 0.2-0.7ppm Cd. General tendency of the concentraion of elements except Mn showed considerably high values at stations in the inner bay. This tendency seemed to be caused by waste water from industrial activities in the adjacent land. It can be thought that the pollution status of the studied area is still limited in the inner part of the day.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.2
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• pp.132-136
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• 2011

The Temporal variability in the food chain structure of bacteria in the sedimentary organic matter was investigated using stable isotope and fatty acid. Potential organic matter sources (Land plant, Marine POM, benthic microalgae, Riverine POM), sedimentary organic matter and bacteria were sampled in Gamo largoon and Nanakita estuary. The main objective of the present study was to determine food sources of bacteria along with temporal variability. Land plant (${\delta}^{13}C$ = -26.6‰ and ${\delta}^{15}N$ = 3.6‰) and Riverine POM (${\delta}^{13}C$ = -25.5‰ and ${\delta}^{15}N$ = 8.9‰) were isotopically distinct from benthic microalgae (${\delta}^{13}C$ = -16.3‰ and ${\delta}^{15}N$ = 6.2‰) and Marine POM (${\delta}^{13}C$ = -20.3‰ and ${\delta}^{15}N$ = 10.3‰). ${\delta}^{13}C$ values of sedimentary organic matter showed a distinct gradient in the range of -20.7‰ to -191‰. The stable carbon and nitrogen isotope values of bacteria in the study were -20.8‰ to -18.6‰ for ${\delta}^{13}C$ and 6.5‰ to 8.6‰ for ${\delta}^{15}N$. From this results based on stable isotope measurements showed that in the bacteria was found to be dominated by Marine POM and Benthicmicoralge during 0 to 20 day. Whereas, terrestrial plant and riverine POM showed little in fluence to bacteria during the experiment.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1997.06a
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• pp.157-158
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• 1997

• Journal of Marine Life Science
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• v.8 no.1
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• pp.8-31
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• 2023

To understand the distribution and formation mechanism of benthic foraminiferal assemblages, grain size analysis, ¹⁴C radiocarbon dating, and benthic foraminifera analysis were conducted on thirty-two surface sediments collected from the continental shelf of the northern East China Sea, respectively. Surface sediment was composed of sandy mud~muddy sand facies with an average of 52.04% of sand, 13.72% of silt, and 34.20% of clay. These sedimentary facies are palimpsest sediment. Benthic foraminifera was classified into a total of 48 genera and 104 species, including agglutinated foraminifera, calcareous-hyaline, and calcareous-porcelaneous foraminifera. The production rate of agglutinated foraminifera increased toward the Yangtze River area while that of planktonic foraminifera increased toward Jeju Island. Dominant species are Ammonia ketienziensis, Bolivina robusta, Eggella advena, Eilohedra nipponica, Pseudorotalia gamardii, Pseudoparrella naraensis. ¹⁴C radiocarbon datings of Bolivina robusta and Pseudorotalia gamardii with the highest production rate were 2,360±40 yr B.P. and 2,450±40 yr B.P., respectively. In the result of cluster analysis, three assemblages composed of P. gaimardii, B. robusta, and A. ketienziensis-P. naraensis were classified broadly. P. gaimardii assemblage is thought to be formed from about 2.5 yr B.P. at the sea area of the Yangtze River to 50 m in water depth affected by fresh water. B. robusta assemblage is thought to be formed from about 2.4 yr B.P. at the sea area of Jeju Island to 50~100 m affected by offshore water. And then, A. ketienziensisP. naraensis assemblage was formed in the northwest sea area (Central Yellow Sea Mud). These distributions and composition of benthic foraminiferal assemblages formed from about 2.5 yr B.P. in the northern East China Sea are thought to be due to the change of benthic ecology environment that occurred by the sea level increase during the late Holocene.

• Journal of Wetlands Research
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• v.22 no.2
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• pp.59-65
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• 2020

The purpose of this study is to determine the origin of organic matter on sediment at Sindu-ri tidal flat. Grain size, organic matter, C/N ratio and the 13C and δ15N ratio were measured at three stations (Stn. A, B, C) of the tidal flat. As a result, the spatial variation in sediment properties showed that organic matter was related positively to the sediment mud content. Organic matters originating from marine particulate organic matter (marine POM) and fish farm particulate organic matter (fish farm POM) showed sedimentation of organic matters at Stn. A, sandy tidal flat, though terrestial plant (TP) and benthic microalgae (BMA) did at Stn.C, muddy tidal flat. Meanwhile, Stn. B, the intermediate property of Stn. A and C, was affected by marine POM and BMA. Furthermore, it was revealed that the amount and origin of organic matters in the sediments depended on spatial variation, and the factors were different from the stations. Particularly, at the Stn. C, the sediment showed high concentration of TOC in terrestrial organic matter and smaller size particles (< 63 ㎛). These facts suggest the many small size particles and organic matter will affect the sediment environmental condition in the Stn. C.