• Fisheries and Aquatic Sciences
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• v.11 no.2
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• pp.103-112
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• 2008

Compressional sound velocities of shelf sediments in the South Sea of Korea, were measured in situ and in the laboratory for six cores. In situ sound velocity was measured using the Acoustic Lance (frequency of 7.5-15 kHz), while laboratory velocity was measured by the pulse transmission technique (frequency of 1MHz). Physical properties were relatively uniform with sediment depth, suggesting little effect of sediment compaction and/or consolidation. Average in situ velocity at each core site ranged from 1,457 to 1,488 m/s, which was less than the laboratory velocity of 1,503 and 1,604m/s. In muddy sediments the laboratory velocity was 39-47 m/s higher than in situ velocity. In sandy sediments, the difference was greater by an average of 116 m/s. Although the velocity data were corrected by the velocity ratio method based on bottom water temperature, the laboratory velocity was still higher than the in situ velocity (11-21 m/s in muddy sediments and 91 m/s in sandy sediments). This discrepancy may be caused by sediment disturbance during core collection and/or by the pressure of Acoustic Lance insertion, but it was most likely due to the frequency difference between in situ and laboratory measurement systems. Thus, when correcting laboratory velocity to in situ velocity, it is important to consider both temperature and frequency.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.6
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• pp.700-707
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• 2003

Surface sediments in the mouth area of Jinhae Bay were investigated to evaluate the benthic environment in terms of geochemical criteria and macrobenthos abundance. Characteristics of the surface sediment distribution exhibited muddy sediments in the most part of study area. Some mixed sediments of coarse sand and mud were distributed along the coastal area of Geoje Island and around the Jeo Islands. Organic matter from ignition loss and total organic carbon from CHNS varied between $8.8-1.7\%,\;and\;4.62-0.77\%,$ respectively. The source of organic matter based on the C/S ratio was mixed with in situ biogenic and terrigenous organic matter. The C/S ratio of organic matter also suggested both an anoxic bottom condition in several parts of the study area. The content of hydrogen sulfide in surface sediment was extremely variable and showed spatio-temporal variation from site to site. In several locations, the content of hydrogen sulfide as an index of eutrophication was over the critical value (0.2 mg/g), suggesting that several parts of the study area were not favorable for the habitat of macrobenthos. The relationship among the number of individuals of marcrobenthos, hydrogen sulfide, and organic matter was not clear, but a potential negative relationship between individuals of marcrobenthos and hydrogen sulfide was indicated.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.772-784
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• 2011

We measured grain size, organic matter, and metallic elements (Fe, Cu, Pb, Zn, Cd, Cr, Mn, Hg, and As) in intertidal sediments collected from six islands in the western part of Jellanam Province in order to evaluate heavy metal contamination in the tidal flat sediments of coastal islands. The evaluation of metal contamination was carried out using geochemical assessment techniques such as sediment quality guidelines (SQGs), enrichment factor (EF), and geoaccumulation index ($I_{geo}$). Surface sediments were classified into four sedimentary facies: sand, gravelly muddy sand, slightly gravelly mud, and silt. The concentrations of heavy metals in intertidal sediments from Jaeun, Amtae, Biguem, and Docho islands showed good positive correlations with mean grain size and ignition loss, indicating that the concentrations of metallic elements in these sediments were dependent on grain size and the organic matter content. The concentrations of heavy metals in sediments from almost all of the stations were lower than two criterion values proposed by the National Oceanic and Atmospheric Administration (NOAA) in the United States. Based on the EF and $I_{geo}$ results, surface sediments were a little polluted for Cr and were moderately polluted for As. Our results suggest that more intensive studies are necessary in the future in order to determine the major source of As in intertidal sediment and to evaluate the As pollution level in macrobenthos.

• Journal of Korean Society on Water Environment
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• v.39 no.4
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• pp.329-342
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• 2023

Turbid water and suspended sediment (SS) load are having negative consequences such as water quality degradation and ecological damage, thus necessitating the establishment of management guidelines to reduce their impact. The present work investigates the spatio-temporal distribution of fish species and the effects of turbid water from 2011-2016 in the upper reaches of Soyang-Dam. The family Cyprinidae is the largest population in the study area, among which Zacco platypus and Zacco koreanus are the dominant species. The diversity of species is relatively abundant in the upper watershed, while the seasonal effect on the population distribution remains unclear. Using two main common components of the empirical orthogonal function (EOF) analysis, the distribution characteristics of 27 species at five survey sites are revealed. Zacco koreanus is found to be predominant at the upstream A-Naerincheon, while Zacco platypus and Rhinogobius brunneus are found to be predominant at the upstream B-Bukcheon. Disturbance of an aquatic ecosystem has a relatively greater impact in the downstream, as-compared to the upper area-the high proportion of forest area is decreased whereas that of agricultural and urbanized areas is increased. The patterns of representative species are changed according to the mid- to long-term effects of turbid water and SS. Accordingly, the significant correlation between the SS load and fish distribution EOF analysis indicates that it should be considered as a potential alternative that can overcome the limitations of impact assessment on turbid water to the Fish Assessment Index (FAI). A comprehensive study examining the long-term effects of SS load to the fish ecosystems with a systematic statistical analysis of sufficiently accumulated data at the national level is needed as future research.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.713-720
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• 2002

In order to provide the basic information on the environmental pollution of Kyungsan province, the contents of Pb, Cd, Cr, Cu, Mn and Zn in soil, stream water, aquatic sediment and groundwater were investigated, and also the values of pH, COD, $KMnO_4-C$,\;NH_3-N,\;NO_2-N,\;NO_3-N$ and $Cl^-$ of stream water and groundwater were determined. The results were as follows. The values of COD, $NH_3-N,\;NO_2-N$ and $NO_3-N$ of the stream waters were very low. The contents of Pb, Cd, Cr, Cu and Zn in the stream waters were respectively at range of $0.014~0.063 mg/{\ell},\;0.004~0.007 mg/{\ell$\mid$, 0~0.045 mg/{\ell},\;0~0.008 mg/{\ell}$\;and\;$0.001~0.175 mg/{\ell}$, and these values were much lower than those of contaminated stream water in Korea. The contents of Cd, Cr, Cu and Zn in the soils were respectively at range of 0.12~O.71 ppm, 0.88~2.65 ppm, 2.86~22.33 ppm and 3.89~26.39 ppm, and these values were much lower than those of ordinary polluted areas in Korea. The contents of Cd, Cr, Cu, As, Zn and Mn in the aquatic sediments were respectively at range of 3.05~3.81 ppm, 14.6~70.6 ppm, 13.74~61.59 ppm, 76.8~465.5 ppm, 12.56~190.83 ppm and 333.3~l188.3 ppm. The values of pH, $KMnO_4-C,\;NH_3-N$, and $NO_3-N$ of the groundwaters were respectively at range of 7.6~8.4, $0~3.95{\ell}$, 0.05~0.15 mg/{\ell}$ and 0.05~0.42 $mg/{\ell}$. The contents of Pb, Cd and Cr in the groundwaters were respectively at range of 0.015~0.061 $mg/{\ell}$, 0.O06~0.009 $mg/{\ell}$ and 0.005~0.045 $mg/{\ell}$.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.2
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• pp.1-17
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• 2015

Ecological reservoir is a multifunctional space where provides the functions of retention, animal habitat and improvement of ecosystem health and landscape. The ecological reservoir of Anteo Eco Park located in Gwangmyeong-si has established to functions for water purification, maintenance of healthy aquatic ecosystem. Because the Anteo Eco Park is located in the site where nonpoint pollutant materials flow in, Anteo Eco Park has potential factors which aquatic ecosystem health deteriorates and damages the habitat of golden frog(Rana plancyi chosenica) which is restoration target species. Therefore, the purpose of this study is to suggest the plan to manage the variables which impede the right functions of aquatic ecosystem by understanding the causal loop diagram for the change of water quality environment and the interaction of predator-prey through system thinking. The results are as follows. First, the study showed that the individual number of golden frog which is an indicator species of Anteo Eco Park is threatened by snakeheaded fish, which is an upper predator. Therefore, balanced food chain should be hold to protect golden frog by capturing the snakeheaded fish which is individual number's density is high, and the monitoring management of the individual number for predator(snakeheaded fish)-prey(golden frog) should be performed. Second, the study represented that water pollution and carnification is caused by the sediment as the dead body of the large emergent vegetation in the winter cumulates as sediment. Ecological reservoir in Anteo Eco Park has been managed by eliminating the dead body of the large emergent vegetation, but the guideline for the proper density maintenance of vegetation community is additionally needed. Lastly, the study showed that aquatic ecosystem of Anteo Eco Park where is contaminated from the inflow of nonpoint pollutants affects the individual number's decline of golden frog and snakeheaded fish. Accordingly, the creation of a buffer area and a substitution wetland is needed in the periphery of the Anteo Eco Park to control the inflow of nonpoint pollutants including organic matters, nutrients and heavy metals. This study will be helpful that Anteo Eco Park improves the regional landscape and maintain healthy aquatic ecosystem space for the park visitors including local residents.

• Korean Journal of Ecology and Environment
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• v.47 no.1
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• pp.62-69
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• 2014

Standing crop distribution of aquatic plants in the West Nakdong River and riparian wetlands in the Nakdong River were surveyed in May, July and September, 2010. Total 25 aquatic macrophyte species (submerged: 9, leaf-floating: 3, free-floating: 5, emergent: 8) were observed during the survey periods. Distribution area of aquatic plants and proportion of submerged communities were highest in Garakchi-deung ($212,032m^2$, 72.7%). The distribution area of aquatic plants was highest in Phragmites australis community ($421,584m^2$), followed by Hydrilla verticillata-Vallisneria natans community ($181,511m^2$), Potamogeton wrightii-Vallisneria natans community ($61,604m^2$), and Hydrocharis dubia community ($49,709m^2$). Garakch-ideung (212,032 kg) also had the highest aquatic plant production, followed by Suanchi-deung (15,546 kg), Daedong (5,813 kg), Dunchi-do (3,963 kg), Maekdo (1,463 kg), Yeommak (571 kg), Jungsa-do (530 kg), and Shinan (300 kg). Average standing crop of the study area were $147.8{\pm}20.8g\;DW{\cdot}m^{-2}$ in 1988, $96.1{\pm}20.0g\;DW{\cdot}m^{-2}$ in 2000, and $172.6{\pm}76.1g\;DW{\cdot}m^{-2}$ in 2010. For a sustainable management of river habitat and food source, aquatic plant should concurrently be surveyed with river environmental variables (i.e. sediment, nutrient, flow).

• Journal of the Korean Applied Science and Technology
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• v.27 no.3
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• pp.249-256
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• 2010

A phytoremediation study has been conducted to see if some known aquatic plants can remove the pesticides, endosulfan-${\alpha},\;{\beta}$ and fenitrothion which are frequently used in the crop protection and golf course management, and are likely to exist as residual pollutants in the aquatic ecosystems. Among the five aquatic plants tested in the microcosms, water lily Nymphaea tetragona Georgi showed the highest degradation efficacies (85~95%) for the three pesticides as opposed to the control(13~26%). The efficacies for the other plants were in the range of 46~80% in the order of Pistia stratiotes, Cyperus helferi, Eichhornia crassipes, and Iris pseudoacorus. Fenitrothion, an organo-phosphorus pesticide, was much more vulnerable to the phytoremediation than the organo-chlorine pesticides, endosulfan-${\alpha}$ and endosulfan-${\beta}$. The kinetic rate constants ($min^{-1}$) for removal of the three pesticides were more than 10 times higher than the control (non-planting) in case of Nymphaea tetragona Georgi. This aquatic plant showed kinetic rate constants about 2 times as much as the lower kinetic rate constants shown by Iris pseudoacorus. The reason for the highest degradation efficacy of water lily would be that the plant can live in the sediment and possess roots and broad leaves which could absorb or accumulate and degrade more pollutants in association with microbes. These results indicate that some of the selected aquatic plants planted near the agricultural lands and wetlands could contribute to remediation of pesticides present in these places, and could be applicable to protection of the aquatic ecosystems.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.273-281
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• 2002

Determination of sediment type is generally based on ground truthing. This method, however, provides information only for the limited sites. Recent developments of remote classification of seafloor sediments made it possible to obtain continuous profiles of sediment types. QTC View system, which is an acoustic instrument providing digital real-time seabed classification, was used to classify seafloor sediment types in the Suyoung Bay, Pusan. QTC View was connected to 50 kHz echo sounder, All parameters of QTC View and echo sounder are uniformly kept during survey. By ground truthing, the sediments are classified into seven types, such as slightly gravelly sand, slightly gravelly sandy mud, gravelly muddy sand, clayey sand, sandy mud, slightly gravelly muddy sand, and rocky bottom. By the first remote classification using QTC View, four sediment types are clearly identified, such as slightly gravelly sand, gravelly mud, slightly gravelly muddy sand, and rocky bottom. These are similar to the result of the second survey. Also the result of remote classification matches well with that of ground truthing, but for sediment type determined by minor component. Therefore, QTC View can effectively be used for remote classification of seafloor sediments.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.663-676
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• 1996

Physical properties and textural parameters of thirty-five piston tore samples recovered from the southeastern coast of Korea (Korea Strait), were investigated using the autopycnometer. The physical properties (porosity, water content, wet bulk density, dry bulk density, gram density, and void ratio) were measured at rather uniform intervals along each core. Sediment texture (grain size, sand, silt, and clay contents) was also measured at the same subbottom depth. The measured and calculated results are; mean grain size $0.57\~8.09\phi(average:3.67\phi)$, porosity $26\~81\%\;(average:\;55\%)$, water content $16.7\~61.4\%(average:\;31.6\%)$, wet bulk density $1.37\~2.18g/cm^3\;(average:\;1.85g/cm^3)$, dry bulk density $2.55\~3.11g/cm^3\;(average:\;2.35g/cm^3)$, grain density $2.40\~3.10g/cm^3\;(average:\;2.85g/cm^3)$, and void ratio $0.56\~2.54$ (average: 0.94). The sediment texture generally coincides well with the bathymetry indicating the influence of Pleistocene-Holocene sea level changes. Also the contours of physical properties are closely related to the sediment texture. Fluctuation of physical properties are similar to the textural variation. It seems that sediment texture is a significant factor in determining physical property in this study area.