• Journal of Food Hygiene and Safety
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• v.9 no.3
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• pp.141-149
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• 1994

To investigate the distribution of Vibrio parahaemopyticus in the southern 4 coastal areas, Vibrio parahaemolyticus was isolated from seawater, shellfish and sediment from May to October in 1991, and antimicrobial effect of grapefruit seed extract (GFSE) on the growth of isolated strains were examined. In the 120 sample from 4 coastal areas, 16 strains of Vibrio parahaemolyticus were isolated and identified. The distribution serotype of isolated strains was 10 types of monovalent k-antiserum. Especially k-5 and k-28 were highly distribyted with 3 and 4 strains. 31.3% of isolated strains showed positive on Kanagawa phenomenon test. All isolated Vibrio parahaemolyticus were sensitive to chloramphenicol and gentamycin, 5 and 6 strains were resistant to streptomycin and colistin, respectively. Isolated strains were compared with geographical, month and sample. The distribution of 16 isolated Vibrio parahamolyticus was high at Hadong with 50%(8 strains), on July with 43.8%(7 strains) and from seawater with 37.5%(6 strains) respectively. Minimal inhibitory level of GFSE to Vibrio parahaemolyticus was 50 ppm. With 100 ppm treatment of GFSE, the destroy of cell membrane function, outflow of cell ingredients and ghost morphology of cell were investigated.

• Ocean and Polar Research
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• v.24 no.4
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• pp.399-406
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• 2002

Trace metals were investigated for the surface seawaters and mussels collected in adjacent sea to the Dokdo during 1999-2000. This study reports the temporal and spatial distributions of trace metals in seawaters and mussels of the Dokdo coastal areas. Clean technique for trace metal analyses was employed in all manipulations including the sampling and pretreatment procedures. The concentrations of dissolved Cu, Cd and Pb in the surface seawaters were similar to those of the previous data in the East Sea. Contents of particulate Al, Fe, Mn and Co were influenced by input of detrital materials from the Dokdo. The average EFs of particulate metals were to the order of Cd > Zn > Pb > Cu > Ni > Mn > Co > Fe, and the high values in Cd and Zn may be closely related to the preferential uptake of biogenic particles. With the exception of Cd, all metal contents in the mussels were in the same ranges with those from other world coastal areas. The Cd accumulation factor of mussel/seawater in this study was abnormally much higher than previous data from the Korean coasts.

• ALGAE
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• v.26 no.3
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• pp.265-275
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• 2011

This study examined the bioaccumulation of the heavy metals copper (Cu) and zinc (Zn) by the giant kelp, Macrocystis pyrifera, by exposing meristematic kelp tissue to elevated metal concentrations in seawater within laboratory aquaria. Specifically, we carried out two different experiments. The first examined metal uptake under a single, ecologically-relevant elevation of each metal (30 ppb Cu and 100 ppb Zn), and the second examined the relationships between varying levels of the metals (i.e., 15, 39, 60, 120, 240, and 480 ppb Cu, and 50, 100, 200, 300, 500, and 600 ppb Zn). Both experiments were designed to contrast the uptake of the metals in isolation (i.e., when only one metal concentration was elevated) and in combination (i.e., when both metals' concentrations were elevated). Following three days of exposure to the elevated metal concentrations, we collected and analyzed the M. pyrifera tissues using inductively coupled plasma atomic emissions spectroscopy. Our results indicated that M. pyrifera bioaccumulated Cu in all treatments where Cu concentrations in the seawater were elevated, regardless of whether Zn concentrations were also elevated. Similarly, M. pyrifera bioaccumulated Zn in treatments where seawater Zn concentrations were elevated, but this occurred only when we increased Zn alone, and not when we simultaneously increased Cu concentrations. This suggests that elevated Cu concentrations inhibit Zn uptake, but not vice versa. Following this, our second experiment examined the relationships among varying seawater Cu and Zn concentrations and their bioaccumulation by M. pyrifera. Here, our results indicated that, as their concentrations in the seawater rise, Cu and Zn uptake by M. pyrifera tissue also rises. As with the first experiment, the presence of elevated Zn in the water did not appear to affect Cu uptake at any concentration examined. However, although it was not statistically significant, we observed that the presence of elevated Cu in seawater appeared to trend toward inhibiting Zn uptake, especially at higher levels of the metals. This study suggests that M. pyrifera may be useful as a bio-indicator species for monitoring heavy metal pollution in coastal environments.

• Ocean and Polar Research
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• v.30 no.4
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• pp.407-418
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• 2008

Seawater samples were collected at discrete depths from five stations across the polar front in the Drake Passage (Antarctic Ocean) by the $20^{th}$ Korea Antarctic Research Program in December, 2006. Nitrate concentrations of seawater increase with depth within the photic zone above the depth of Upper Circumpolar Deep Water (UCDW). In contrast, ${\delta}^{15}N$ values of seawater nitrate decrease with depth, showing a mirror image to the nitrate variation. Such a distinct vertical variation is mainly attributed to the degree of nitrate assimilation by phytoplankton as well as organic matter degradation of sinking particles within the surface layer. The preferential $^{14}{NO_3}^-$ assimilation by the phytoplankton causes $^{15}{NO_3}^-$ concentration to become high in a closedsystem surface-water environment during the primary production, whereas more $^{14}{NO_3}^-$ is added to the seawater during the degradation of sinking organic particles. The water-mass mixing seems to play an important role in the alteration of ${\delta}^{15}N$ values in the deep layer below the UCDW. Across the polar front, nitrate concentrations of surface seawater decrease and corresponding ${\delta}^{15}N$ values increase northward, which is likely due to the degree of nitrate utilization during the primary production. Based on the Rayleigh model, the calculated ${\varepsilon}$ (isotope effect of nitrate uptake) values between 4.0%o and 5.8%o were validated by the previously reported data, although the preformed ${\delta}^{15}{{NO_3}^-}_{initial}$ value of UCDW is important in the calculation of ${\varepsilon}$ values.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.3
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• pp.134-139
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• 2005

The purpose of this study is to quantify the penetration behavior of spilled weathered oil and dispersed oil and to evaluate the influence of the penetrated oils on seawater infiltration in tidal flat environment. The penetration depths of the spilled oils into the tidal flat sediments were gradually deeper according to increase the stranded oil volume. The penetration depth of stranded oil were abruptly dropped at first falling tide, but were not significantly fluctuated after that. Moreover, hydrocarbon concentration was most high within the upper 2 cm. Seawater infiltration was decreased in proportion to the stranded oil volume. Dispersed oil was easily permitted the seawater infiltration than weathered oil and crude oil. Therefore, quick cleaning actions fur penetrated oil will be required far recovery of seawater infiltration, because the seawater contains oxygen and nutrients required for the survival of benthic organisms in tidal flat.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.457-464
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• 2005

In the case of tunneling, the equilibrium state of hydro-geologic environments destroy and change abruptly in some section of whole works. Specially, it's very possible for seawater to intrude toward the site of tunnel if the field is nearly located in a costal region. In this study, we have evaluated the mechanism related between groundwater flow and seawater intrusion that by impacts of tunneling. Various hydro-geological field tests have performed for getting four representative hydrogeologic properties of geologic formations such as transmissivity (T), storativity(S), longitudial dispersity(${\alpha}_L$), and effective porosity($n_e$). For the effect of tunneling, the numerical model was first simulated based on the governing equation of groundwater flow. The results showed that the maximum drawdown was 17.2m and the total inflow into the tunnel had the range from 0.48 to $3.63m^3/day/m$. Secondly, the three dimensional numerical model was analyzed to investigate a characteristic of seawater intrusion based on the previous simulated results of groundwater flow. The results showed the seawater moved as the range of $200{\sim}220m$ from the initial interface between seawater and groundwater toward the tunnel.

• Korean Journal of Environmental Agriculture
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• v.36 no.2
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• pp.129-134
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• 2017

BACKGROUND: Yeasts are used in a variety of industries. However, most industries are biased toward Saccharomyces cerevisiae ; so we sought to explore non-conventional yeasts (NCY). This study aimed to isolate yeasts from seawater collected from the East Sea of Korea and to analyze the NCY. METHODS AND RESULTS: We first collected seawater and performed pure isolation using four kinds of medium (GPY, DOB + CSM, DG18, and SCG). In total, 314 strains and 17 genera were isolated by ITS sequencing, including Aureobasidum pullulans (236 strains), Cryptococcus (19 strains), Cystobasidium (18 strains), and Rhodotorula (9 strains). Upon in-depth analysis, A. pullulans, the most dominant genus (236 strains), was divided into Group II (147 strains), Unknown I (8 strains), and Unknown II (49 strains). CONCLUSION: In this study, a total of 314 strains were isolated from seawater; many of these yeasts have been found and reported in seawater previously. In-depth analysis of A. pullulans, showed the dominance of Group I (21 strains) and Group II (147 strains) We also discovered Unknown I (8 strains) and Unknown II (49 strains), which have not been reported previously.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.495-504
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• 1996

The concentrations of dimethylsulfide (DMS) were determined from both seawater and the overlying atmosphere from a station located in the Masan Bay area during a ten-day field campaign period of January 1996. The resulting data were also used to derive saturation ratios (SR) as well as sea-to-air fluxes of DMS. The concentrations and fluxes of DMS for both reservoirs varied extensively over two to three orders of magnitude: DMS in air and seawater were measured at 9 to 4,300 pptv (mean: 600 $\pm$ 1, 170, N=18) and at 0.24 to 10 nM (4.0 $\pm$ 3.4, N=13), respectively, while its fluxes were found from 0.02 to 23 mol $m^{-2} day^{-1} (3.1 \pm 6.8, N=11)$. A comparative analysis between our data and previously reported ones indicate that its atmospheric concentrations are abnormalously high, but its seawater counterparts are slightly lower than expected. In light of high pollution levels of organic-rich materials in and the associated high biological productivity of the study area, the sea-to-air-fluxes derived are notably low relative to those values typically reported from the coastal areas. These complicated features of DMS distributions/fluxes in the study site indicate that the near-by port- based anthropogenic activities from various industrial plants strongly interfere with natural processes leading to the production and release of DMS. It was however striking to find out relatively strong signals of diel cycle in its saturation ratios, concentration gradients between seawater and atmosphere, and the associated fluxes. Although it is yet difficult to provide meaningful explanations for the observed phenomena, the existence of clear diel cycle in some DMS-related parameters suggests that the natural processes may nonetheless exert important controls on the regional cycling of atmospheric sulfur species, of particular DMS.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.4
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• pp.450-455
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• 2018

We examined correlations of the density of fish farms with the distributions of indicator bacteria (Escherichia coli, fecal streptococci) and a bacterial fish pathogen (Streptococcus parauberis) off the coastline of Jeju Island. Seawater samples were collected at four coastal sites on the Island [Aewol (control), Gujwa, Pyoseon and Daejeong] in June, August and October 2016. The indicator bacteria were generally more frequently isolated from samples taken in August when water temperatures and human activities on nearby beaches were highest. Although fish farms were least common at Daejeong, the numbers of isolated fecal indicator bacteria were highest in the seawater and effluent water collected from this site. Hence, fish farms were not likely major contributors of indicator bacteria at Daejeong. We found discrepancies between the isolated bacterial counts and the predicted bacterial copy numbers deduced from our qPCR results, indicating that this pathogen may exist in a viable but non-culturable (VBNC) state in seawater. Thus, livestock wastewater and chemical fertilizer loading off Jeju Island may negatively impact seawater quality more than the effluent released from fish farms does.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.1
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• pp.83-90
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• 2017

To understand the spatial-temporal distribution of seawater in Korea's South Sea, seawater movement and the distribution of water temperature has been analyzed using a hydrodynamic model (the Princeton Ocean Model). The directions of tidal currents were generally westward during flood tides and eastward during ebb tides. Northeastward Tsushima Warm Currents in the open sea, which is deeper than 50m were stronger than in coastal areas. Analysis of data from the hydrodynamic model showed that the water temperature in the semi-closed bay was relatively higher ($26{\sim}28^{\circ}C$) than in the open sea ($18{\sim}22^{\circ}C$). The exchange volume of semi-closed seawater was $10,331m^3/sec$ in Gwangyang Bay, $16,935m^3/sec$ in Yeosu-Gamag Bay and $13,454m^3/sec$ in Geoje-Hansan Bay. Therefore, it was shown that the lower seawater exchange volume is, the higher seawater temperature will be.