• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.324-332
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• 2019

In this study, the possibility of a follow-up study on environmental pollution in domestic freshwater was identified by analyzing fish otoliths using Laser ablation-inductively coupled mass spectrometry (LA-ICP/MS). Fish otolith are known to be affected by the environment in which fish live. As a result, research on this subject is active in many countries; however, this is not the case in Korea. Therefore, in this study, the possibility of tracing environmental pollution using fish otoliths was identified by analyzing the components of metal elements used as indicators for environmental pollution. For the component analysis of metallic elements LA-ICP/MS, which can shorten analysis time by reducing the pretreatment process, was used. Sampling was conducted by dividing the research and the background area and carp, a freshwater species, was selected as the experimental fish species subject. Based on the established LA-ICP/MS conditions, the concentration of the metallic elements in the fish otoliths collected in the research area was 2202.9 mg kg^-1, 2.03 times higher than the 1,086.3 mg kg^-1 in the background area. All elements except for Li and U, were found to be higher in the research area than in the background area. Compared with the sediment measuring net analysis data, the distribution tendency of Zn, Pb, and Cu in sediment metal element concentrations in the two regions and distribution of metal element concentration in fish otoliths were similarly shown. These results confirm that fish otoliths can be used to track environmental pollutants, such as in sediments.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.513-523
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• 2017

We evaluated the viability of phytoplankton along the salinity gradient in the flood and ebb tides of spring tide of February and the ebb tide of neap tide of March 2017 in the Seomjin River Estuary. Additional laboratory experiments were also conducted to determine the reason of the pH changes along the salinity gradient using the field natural sample in February. In field, saltwater was well mixed at downstream vertically and the salinity gradient was horizontally appeared toward upstream of freshwater zone. There were strong negative correlations between salinity and nutrient (nitrate + nitrite R=0.99, p<0.001, and silicate R=0.98, p<0.001), implying that those two nutrients of freshwater origin were gradually diluted with mixing the saltwater. On the other hands, relatively high phosphate concentration was kept in the stations of saltwater over 15 psu, indicating that it was caused by resuspended sediments of Gwangyang Bay and downstream by tidal water mixing.Among phytoplankton community structure in winter, Eucampia zodiacus have occupied to be c.a. 70 % in the most stations. Based on the field survey results for survivability of phytoplankton by phytoPAM instrument, there was positive correlations between salinity and chlorophyll a (R=0.82, p<0.001) and, salinity and active chlorophyll a (R=0.80, p<0.001), implying that the dominant marine diatom species may have significantly damaged in low salinity conditions of upstream. Also, maximum mortality rate of phytoplankton caused by low salinity shock was appered to be 75% in the upstream station. In particular, the pH in spring tides of February had tended to increase with high phytoplankton accmulated stations, suggesting that it was related with absorption of $CO_2$ by the photosynthesis of dominant diatom. In laboratory experiments, phytoplankton mass-mortality caused by low salinity shock was also occurred, which is confirmed with reducing the photosynthetic electron transport activity. Following the phytoplankton mass-mortality, bacteria abundance was significantly increased in 24 hours. As a result, the mass-proliferating bacteria can produce the $CO_2$ in the process of biodegradation of diatoms, which can lead to pH decrease. Therefore, marine phytoplankton species was greatly damaged in freshwater mixing area, depending on along the salinity gradient that was considered to be an important role in elevating and reducing of pH in Seomjin River Estuary.

• 한국해양학회지
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• v.30 no.2
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• pp.77-90
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• 1995

The sedimentary environments and biostratigrapy of the tidal sediments off the Mankyung-Dongjin River estuary were studied based on sedimentary facies and diatom assemblage analysis. Sediment facies from the five vibracores are mainly clay, silt, and sand facies. The clay and silty sediment facies are more dominant than the sandy facies, and contain diatom frustules. The frequency of the diatom frustules are rate to common, but not found in sandy sediment facies. Bigeneric structures such as burrow and non-bigeneric primary sedimentary structures such as laminated sand and mud or silt and mud couplets, flaser bedding, ripple-cross lamination are found in several stratigraphic levels of the sedimentary sequences. A total of 219 species and varieties, belonging to 61 genera has been identified in the present study. Among them, paralia sulcata is the most abundant species about 30 to 50% of the total diatom frustules. Another predominant species are Cyclotella striata. Thalassionema nitzschioides. Actinoptychus undulatus. Delphineis surirella, Raphoneis amphiceros. Most of the diatoms occurred in this study area are marine, marine-brackish water, and brackish water species, and are benthic and tychopelagic or meroplanktonic species. Also, most of the species are coastal to littoral and littoral to inner neritic species. The occurrences of freshwater species, about 1 to 5% is higher than that of the Namyang Bay tidal sediments. The ecological properties of the diatoms occurred in the study area and primary sedimentary structure such as flaser bedding ripple cross bedding indicate that the deposits are formed under coastal or littoral to subeditorial environments such as tidal zone which was subjected to the influenced of stream water and was more strongly influenced by temperate to warm water than cold water. The sedimentary environments have not been changed distinctively during the time of deposition. The vertical distribution pattern of diatoms in the study area is studied by Q-mode cluster Analysis using spss/pc+ (ver.4.0). The results show that the three cores (GE-3, GE-11, GE-12) are divided into two diatom assemblages, respectively. Biostratigraphic correlation using the data of Q-mode Cluster Analysis are attempt in this study.

• 한국해양학회지
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• v.27 no.4
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• pp.303-310
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• 1992

Studies on the distribution of nitrogenous compounds, and respiratory oxygen consumption rate were carried out in Masan Bay, Korea where large amount of industrial and domestic wastewaters are discharged. In August 1986 the surface layer was significantly influenced by freshwater input. Below the seasonal pycnocline, an oxygen-deficient condition developed in a large area of Masan Bay. Concentrations of DIN, DON and PN were 735.6, 1261.8 and 48.5 umol/l at the head, and 79.1, 73.0 and 39.5 umol/l at the mouth of the inner Masan Bay, respectively. Phytoplankton carbon production was 2,695 mgC/m$^2$/day at the mouth of inner Masan Bay. Dissolved oxygen contents were lower than 1 ml/l from 3 m depth in inner Masan Bay and from 10 m depth in the outer Masan Bay. The high concentration of ammonium and phosphate in the lower layer suggests the active degradation of organic materials in the bottom waters and leaching from sediments. The ERS activity was 232.1 ul O$_2$/l/h in the surface waters of the innermost part of Masan Bay and respiratory oxygen consumption is likely to proceed at a rate of 442 ml O$_2$/m$^2$/day in the bottom waters of this bay. Nitrate removal rate was estimated to be 0.25 umol/l/day via denitrification in the bottom waters of the Masan Waterway. It is estimated from the ETS activity that, at the mouth of inner Masan Bay, 9.3-10.5% of carbon fixed in the upper layer was decomposed below the themocline.

• Economic and Environmental Geology
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• v.45 no.5
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• pp.551-564
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• 2012

This study carried out palynological analysis and seismic interpretation to establish a stratigraphic and environmental reconstruction mainly based on fossil palynomorphs and seismic reflection data correlated with the oil exploation well (BP-1) located in the Sora Sub-basin. There were frequent environmental and floral changes due to sea level change in the Sora Sub-basin. The palynomorph assemblages found in the well sediments enabled paleoecological zonation of the well sediment sequence resulting in 4 zones: Ecozone III, Ecozone IV, Ecozone V, Ecozone VI. Index fossils among palynomorphs indicate geological ages of the units within the well ranging from Eocene to Pleistocene, and paleoenvironment varies from freshwater to inner neritic marine. Previous studies suggest that the marine deposits were slightly different in stratigraphic range from well to well. It is considered the difference is credited to geomorphological setting. This study also shows stratigraphic correlation between existing wells and BP-1 well to establishes a standard stratigraphy of the Domi Basin.

• Journal of fish pathology
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• v.6 no.2
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• pp.205-218
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• 1993

On the development of hirame(Paratichtys olivaceus) culture, outbreak of scuticociliata infection was reported to cause severe damage in Japan. To establish effective measures for isolation and cultivation of this ciliate, we tried to culture this pathogenic ciliate using medium for bacteria and fish cell lines in vitro. Scuticociliata from the brain tissues of infected fish was aseptically inoculated to CHSE-214 cells cultured in MEM-10 without antibiotic. Scuticociliata grew well and the number of ciliate reached $10^6\;cells/ml$ at temperatures of $15^{\circ}C$ to $20^{\circ}C$ for 10d. The number of ciliate cultured in the cell lines is 10 times higher than the numbers cultured in the liquid medium alone. This ciliata could be cloned by dilution method. Scuticociliata isolated could grow well on 42 different cell lines that were established from marine fish, warm freshwater fish, and salmonids. This ciliate could be preserved in liquid nitrogen for more than 6 months. Subsequently, we observed the optimal temperature and salinity for growth, and tested the sensitivities of this organism to formaldehyde, flagyl(Metronidazole), Ekuteshin(Combination compound of sulfamonometoxin and ormethoprim), and ozonixation. Optimal temperature for growth was $25^{\circ}C$ and salinity was 1.0 to 1.5%. Washed scuticociliata was killed by formaldehyde at the concentration of 50ppm for 10min, but was not completely killed even at a high concentration of 400ppm for 20min in MEM-5. Flagyl and Ekuteshin can inhibit the growth of scuticociliata at the concentration of 1,000 and $100{\mu}g/ml$ in MEM-10, respectively. More than 99% of this scuticociliata could be killed by ozonization at a dose equivalent to $1.0mg/\ell$ oxidant for 30sec in sea water. Isolated scuticociliata showed the pathogenicity to the cultured hirame by artificial infection(I. P. injection, $10^5\;cells$/fish). The number of scuticociliata in the water could be counted by most probable number(MPN) method using tissue culture, and the minimum detectable number was $1.8\;cells/\ell$. The number in the reservoir tank for water supply to the culture tank was 110 cells/l. After cleaning by elimination of the sediments from of the reservoir tank and disinfected with formaldehyde, number of scuticociliata decreased and was counted less than $1.8\;cells/\ell$ and infection rate of cultured hirame was decreased.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.2 s.29
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• pp.111-118
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• 2007

Simple box budgets models are useful tools to understand the phenomena of natural system and to provide an insight into the complex processes including physical, chemical and biological processes occurring in natural system. Budgets of fresh water, salt and nutrients were estimated in order to clarify the characteristics of seasonal material cycle in the Masan Bay. Outflow volume of freshwater into system was approximately $307.4\times10^3\sim1,210\times10^3\;m^3/day$. Inflow masses of DIP and DIN were approximately $410.8\sim795.7\;kg/day$ and $4081.4\sim6525.3\;kg/day$, respectively. DIN is expected to accumulate in the system. The removal of nutrients from bottom sediments will contribute to the reduction of 21.0% of COD concentration in the system.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.3
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• pp.117-123
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• 2006

The water quality before and after a typhoon was investigated as a part of a study on the increase of organic matter and on the fundamental measures to counter chemical oxygen demand (COD) in the eutrophic Soho coastal seawaters of Gamak Bay. The dissolved oxygen (DO) saturations were <54% when water column was stratified. The DO saturation was similar at surface and in the bottom layer after a typhoon $(78\sim88%)$, and a very high DO saturation (234%) was observed in the surface water after mass phytoplankton growth. The highest values of $NH_4-N,\;NO_3-N,\;PO_4-P$, and $SiO_2-Si$ were 18.22, 38.90, 1.58, and $52.10{\mu}M$, respectively, when freshwater entered after heavy rainfall events. In addition, high concentrations of $NH_4-N,\;PO_4-P$, and $SiO_2-Si$ were detected with low DO saturations in bottom water (>5m). A maximum chlorophyll (Chl.) concentration of $311.0{\mu}gl^{-1}$ was observed after typhoon, when a high-density Scrippsiella trochoidea red tide occurred with cell density of 42,000 cells $ml^{-1}$. The algal growth potential (AGP) was high after the typhoon. Nitrogen was always a limiting nutrient for phytoplankton growth. The highest COD level was $10.55mgl^{-1}$, and the main reason of the variation in COD was likely to be phytoplankton growth $(r^2=0.612,\;p=0.000)$. Organic matter, which entered the water column when the typhoon stirred the sediments, seems to have little effects on COD increase.

• The Korean Journal of Quaternary Research
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• v.33 no.1_2
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• pp.59-68
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• 2021

The maximum upper limit of seawater inflow can be recognized by the acid-resistant dinoflagellate cysts and salt-marsh pollen encountered from surface samples in the lower reach of Jujin Stream facing Gomso Bay. Based on their relative yield ratio, the downstream area of Jujin Stream could be further subdivided into coastal marine, brackish-upper limit brackish, and freshwater environments. The abundance of dinoflagellate cysts from JJR-41 to JJR-36 sites reflects that this area is a coastal marine. In the section between JJR-35 and JJR-5 sites, dinoflagellate cysts associated with pollen derived from riparian or salt-marsh (e.g., reeds and sedges) appear to reflect the brackish environments. It may be indicated that dinoflagellate cysts appear up to the JJR-4 site, which is the maximum upper limit where seawater flows up to this point at high tide. This analysis is relatively well corresponding to the hypothetical inundation map showing the maximum flooding area where seawater can flow at high tide.

• Korean Journal of Ecology and Environment
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• v.41 no.spc
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• pp.68-76
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• 2008

This study examined the inhibition effects of a freshwater bivalve (Unio douglasiae) and a submerged plant (Potamogeton crispus) on the cyanobacterial bloom (Oscillatoria sp.). The experiment were conducted in aquarium $(50cm{\times}65cm{\times}120cm)$ with lake sediments in the bottom of the aquarium in 10 cm thick. Before the experiments, artificial cyanobacterial bloom was induced with the addition of lake sediment and CB medium. Total 12 transparent acrylic cylinders (${\Phi}19cm$, height 40 cm) were placed in the aquarium, and within which bivalves and plants were placed in various conditions such as the control (C), plant addition (P:5 stems), mussel addition (U:2 individuals), and both mussel and plant addition (PU: the same quantity as used in each treatment). The experiment was conducted in triplicate during 7 days. pH, dissolved oxygen (DO), electric conductivity (EC), salinity, cyanobacterial cell density, chlorophyll-${\alpha}$ concentration, and mussel filtering rate were monitored daily. At the end of the experiment, total phosphorus (TP), total nitrogen (TN), and plant height and weight were measured. Overall, a large degree of cyanobacterial growth inhibition appeared in both P and U treatments, and the effect was highest in the U treatment, followed by P and PU. The combined treatment of both U and P did not show any synergic effects compared to the effect in separated treatment. In all enclosures of the treatments chlorophyll-${alpha}$ (Chl-${alpha}$) concentration decreased until 36 hours after the additions of the plants and mussels. In contrast, Chl-${alpha}$ concentrations increased in PU enclosures after 36 hours. The same trend was shown in the cell density of Oscillatoria. pH and DO gradually decreased until 120 and 144 hours, respectively, in the P and PU enclosures. TP concentration increased in the mussel enclosures (U and PU), while TN concentration largely decreased in the plant enclosures (P and PU). Our results suggest that applied bivalve (Unio) and submerged plant (Potamogeton) seemed to have a potential effect on the growth inhibition of cyanobacteria, but their combined application may have an antagonistic effect to diminish the degree of the inhibition.