• Journal of Life Science
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• v.18 no.4
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• pp.482-487
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• 2008

In this study, we screened and identified the bacterial strain showing high alkaline pretense inhibitor activity from marine environment. Nine bacterial strains with alkaline pretense inhibitor activity were isolated from marine sediments. Among them, strain C12 had the highest alkaline pretense inhibitor activity and was selected for further taxonomical study. On the basis of morphological and physiological characteristics, strain C12 was identified as the genus Streptomyces. A phylogenetic analysis of the 165 rDNA showed that the isolated strain was actually a member of the genus Streptomyces, because the determined sequence exhibited a higher homology with Streptomyces thermocarboxydus. Morphological characteristics showed cylindrical spore chain and smooth spore surface by scanning electron microscope. Strain C12 was grown on all media except for ISP 9 agar. This strain could be grown in the medium containing up to 9% NaCl.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.3
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• pp.139-144
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• 2005

To investigate the long-term variation of water qualities, we have daily monitored physio-chemical characteristics of surface water in the Geum River estuary from June 1996 to April 2004. We found that the water qualities were determined by three dominant factors : 1. fluvial input from Geum River ($28.3\%$), 2. chemical processes such as nitrification and phosphate addition originated from sediment resuspension and domestic sew- age input ($18.6\%$), 3. biological processes such as nutrient consumption by primary producers ($13.5\%$). The factor 1 (fluvial input) effectively affected the water quality of the estuary particularly during the normal or low river discharge. The factor 2 (chemical processes) and the factor 3 (biological processes) showed distinct seasonal differences due to their relative strengths of biological activities. The factor 3 was a governing parameter during the period of spring algal bloom in 2004. For the spring period, an empirical equation derived from the multi-regression analyses showed that the in-situ chlorophyll-a distributions in the estuarine water were successfully simulated by the phosphate concentrations and N/P ratios. Therefore we suggest that phosphate functions as a limiting factor for the primary productivity in the Geum River estuary for the dry season, especially during spring.

• 한국해양학회지
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• v.26 no.3
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• pp.223-241
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• 1991

In order to study the formation and structure of tidal fronts and their influence on the distribution and productivity of phytoplankton in the outer of Kyonggi Bay, analyses on the water temperature data from 1977 to 1986 and 3 surveys from 1981 to 1986 were carried out in the mid0eastern coast of the Yellow Sea. Temperature gradients and dissolved oxygen gradients were implied that the tidal fronts are formed at the outer of the Kyonggi Bay along the western side of Tae-An peninsula from spring to summer. the formations of tidal fronts in this study area influence the distribution of phytoplankton and primary productivity. The standing stocks, chlorophyll concentrations and primary productivity of phytoplankton in the frontal area are higher than those of the outer stratified waters and the inner coastal mixed waters. These high production in the frontal area are resulted from good light condition and rich nutrient within the water columns. With a boundary of frontal area, there are relatively high chlorophyll concentrations and primary productivity in the coastal mixed waters while there are low chlorophyll concentrations and relatively high primary productivity in the stratified waters. These relatively high primary productivity in the outer area are resulted from the high potential production by nanoplankton in the surface layer and the high production of tychopelagic diatoms under the thermocline with the deep transparency.

• 한국해양학회지
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• v.7 no.1
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• pp.1-14
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• 1972

Seasonal changes in nutrients and suspended organic particulates were measured in the estuary of Nak-dong River in relation to the black laver bed. Monthly measurements of water temperature, pH, dissolved oxygen, nutrients ( $NH_4$-N, $NO_2$-N, $NO_3$\-N, $PO_4$-P and $SiO_2$-Si) and organic suspended particulates (organic carbon and nitrogen) were determined at five stations from February through December, 1970. PH varied 7.6-8.4 with an average of 8.0, and percent saturation of dissolved oxygen were 71-147% with an average of 100.8%. Studies gave evidence that Nak-dong River estuary is strongly enriched with nutrients. Concentrations of nutrients were: 0.13-12.54 ${\mu}g$-atoms/${\iota}$ (averaging 1.63 ${\mu}g$-atoms/${\iota}$) for $NH_4-N$, 0.12-2.09 ${\mu}g$-atoms/${\iota}$ (averaging 0.71 ${\mu}g$-atoms/${\iota}$) for $NO_2-N$, 3.46-56.79 ${\mu}g$-atoms/${\iota}$ (averaging 21.54 ${\mu}g$-atoms/${\iota}$) for $NO_3$-N, 4.04-57.90 ${\mu}g$-atoms/${\iota}$ (averaging 23.79 ${\mu}g$-atoms/${\iota}$) for total soluble nitrogen, 0.18-5.05 ${\mu}g$-atoms/${\iota}$ (averaging 0.96 ${\mu}g$-atoms/${\iota}$) for $PO_4$-P, and 18.33-133.29 ${\mu}g$-atoms/${\iota}$ (averaging 71.57 ${\mu}g$-atoms/${\iota}$) for $SiO_2$-Si, respectively. These nutrient levels were considerably higher compare with other productive laver beds of Wan do and Pyung-il Do in Korea or Ise Bay in Japan. Concentrations of suspended organic particulates varied 55-648 ${\mu}g/{\iota}$ (averaging 392 ${\mu}g/{\iota}$) with organic carbon, 30-155 ${\mu}g/{\iota}$ (averaging 92 ${\mu}g/{\iota}$) with organic nitrogen, and its carbon-nitrogen ratios were varied within 1.5-8.4 with an average of 4.6.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.1
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• pp.1-17
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• 2017

This study was conducted to investigate the nutrient distribution and controlling factors in small stream estuaries. The seasonal variations of nutrient concentration (nitrate, ammonium and phosphate) were observed from 2010 to 2012 in the three streams located in Dang-hang (closed estuary: Go-seong, open estuary: Gu-man and Ma-am). The nutrient concentrations in Go-seong were significantly higher than other estuaries, because Go-seong is relatively large and has large nutrient load from the watershed. The dyke located at the estuary, also, caused the high nutrient concentration by reducing the dilution and increasing residence time. In all three streams, nitrate concentration was high at upstream and decreased toward the downstream, because high load of nutrient input were located at upstream. Dilution and biogeochemical removal toward the downstream also caused the trends. Especially, denitrification, a typical nitrogen removing process showed clear tendency of gradual decreasing from upstream to downstream. However, Ammonium and phosphate concentrations were high at upstream and decreased toward the downstream only when the nutrient loads from the rivers were high. Nutrient concentrations were low in summer and high in winter. Freshwater discharge in summer caused a decrease of the residence time and increase of the transport of nutrients to downstream and reduced the nutrient concentrations in the estuary. Nutrient removal by the biological production during high temperature periods also affected the low nutrient concentrations. Small stream estuaries showed distinct nutrient dynamics. It is necessary to understand these characteristics in order to properly manage the small stream estuary.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.1
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• pp.12-27
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• 2007

This fundamental studies on for the productivity improvement and laborsaving of purse seine fishery. Given the difficulty posed from the distortion of net shape caused by the external forces, such as tide, at the time of shooting and pursing, we set the 4 steps of 0, 2, 4 and 6cm/sec in flow velocity in the flume tank for the experiment in order to examine those characteristics. We used two model seines designed on the scale of 1 to 180 based on the power block seine, which is the mackerel purse seine generally used in the near sea of Jeju Island and triplex seine, which is the mackerel purse seine of one boat system fishing expected in the future, for the experiment, and interpreted the characteristics of several motion in water, such as the shape of seine, the change in tension and area during pursing and its the analysis results are as follows. Though the experiment could be conducted up to 6cm/sec of flow velocity that was defined, the experiment could not go on because of the severe distortion in the seine at the flow velocity in excess of 6cm/sec. As for the depth of leadline and reduction rate of side area of seine when the pursing is connected, P seine turned out to be slightly higher than T seine, and the hauling speed and reduction rate of upper area of seine were found similar to each other. The correlation between the hauling time (Ht) and depth of lead line (Dhp, Dht) of P seine and T seine can be expressed by the equation, that is, Dhp=(0.99Pt-7.63)Pt+69.01, Dht=(1.03Pt-7.73)Pt+66.74. The correlation between the hauling time and hauling velocity (Hpp, Hpt) can be expressed by the equation, that is, $Hpp=-0.06Ht^2+0.88Ht+0.78,\;Hpt=-0.05Ht^2+0.81Ht+0.98$ here, Pt is pursing time. And the correlation between the pursing time and the reduction rate of side area (sArp, sArt) can be expressed by the equation, that is, $sArp=-0.48Pt^2+14.79Pt-16.74,\;sArt=-0.45Pt^2+14.56Pt-16.48$. The reduction rate of upper area of seine (tArp, tArt) can be expressed by the equation, that is, $tArp=0.34Pt^2-0.66Pt-0.74,\;tArt=0.34Pt^2-0.27Pt-1.80$. In addition, the correlation between the pursing time and tension of purse line (Tep, Tet) can be expressed by the equation, that is, $Tep=2.79Pt^2+2.26Pt-0.60,\;Tet=2.14Pt^2+8.08Pt-27.50$.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.1-7
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• 2020

As of 2018, Steel slag was generated approximately 24.23 million tons. Howeve, except blast furnace slag, steel slag is a typical by-product which does not have a clearly defined purpose in recycling. Thus, countries around the world are putting great efforts into developing a purpose for the recycling of steel slag. The vast habitat foundation of marine life has been destroyed due to recent reckless marine development and environment pollution, resulting in intensification of the decline of marine resources, and a solution to this issue is imperative. In order to propose a method to recycle large amounts of by-product slag into a material that can serve as an alternative to natural aggregate, the engineering properties and applicability for each mixing factor of environment friendly porous concrete as a material for the composition of seawater purification were in this study. Regarding the nutrient elution properties, it was clear that the nutrients continuously flowed out up to an immersion time by 8 months in natural seawater; the nitrogenous fertilizer displayed excellent elution properties in this regard.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.2 s.25
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• pp.75-79
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• 2006

In order to study the characteristics of water quality in coastal water and mechanism of phytoplankton blooms, factors of water quality were investigated in diatom bloom area due to rainfall event and no diatom bloom area Diatom blooms occurred after heavy rain and the dominant species were Skeletonema costatum($1,200{\sim}5,000cells/mL$) and Thalassiosira spp.($750{\sim}1,200cells/mL$). In diatom bloom area, water temperature, pH, and dissolved oxygen were observed at higher level than in no diatom bloom area Although these two areas were only 20 meters apart from each other, sharp difference in coastal water quality between two areas was observed. In diatom bloom area, concentrations of nitrogen, phosphorus, and silicate were observed at lower level than in no diatom blooms area. This seems to be due to inflow of much trace metal such as Fe, Mo, Se and so on than nitrogen, phosphorus, and silicate by rainfall events. However, distinct differences in DIN/DIP and $DIN/SiO_2-Si$ between these two areas were not observed.

• International Area Studies Review
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• v.15 no.3
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• pp.471-491
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• 2011

This study is to analyze the determinants of inflow FDI with panel data of 12 provinces in western region of China for the period, 1990-2007, from the perspective of market-oriented FDI and production-efficiency-oriented FDI. The empirical findings are following. First, the empirical results prior to the start of western development program show that the GRDP, the intense of industrialization and university graduates per 10,000 residents have positive coefficient signs at the significant level, while wage level has a negative and significant value. Second the empirical results using the data after the launching of the western development program show that the GRDP, the intense of industrialization have positive relations with FDI, while openness in terms of the ratio of international trade to GRDP and the wage level have negative coefficients. Finally, this thesis finds that the empirical results for both periods are very similar, which suggest that the economic structure in western region has not changed significantly even though almost a decade passed since the western development program launched.

• Journal of Environmental Health Sciences
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• v.45 no.2
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• pp.192-202
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• 2019

Objectives: According to the central limit theorem, the samples in population might be considered to follow normal distribution if a large number of samples are available. Once we assume that toxicity dataset follow normal distribution, we can treat and process data statistically to calculate genus or species mean value with standard deviation. However, little is known and only limited studies are conducted to investigate whether toxicity dataset follows normal distribution or not. Therefore, the purpose of study is to evaluate the generally accepted normality hypothesis of aquatic toxicity dataset Methods: We selected the 8 chemicals, which consist of 4 organic and 4 inorganic chemical compounds considering data availability for the development of species sensitivity distribution. Toxicity data were collected at the US EPA ECOTOX Knowledgebase by simple search with target chemicals. Toxicity data were re-arranged to a proper format based on the endpoint and test duration, where we conducted normality test according to the Shapiro-Wilk test. Also we investigated the degree of normality by simple log transformation of toxicity data Results: Despite of the central limit theorem, only one large dataset (n>25) follow normal distribution out of 25 large dataset. By log transforming, more 7 large dataset show normality. As a result of normality test on small dataset (n<25), log transformation of toxicity value generally increases normality. Both organic and inorganic chemicals show normality growth for 26 species and 30 species, respectively. Those 56 species shows normality growth by log transformation in the taxonomic groups such as amphibian (1), crustacean (21), fish (22), insect (5), rotifer (2), and worm (5). In contrast, mollusca shows normality decrease at 1 species out of 23 that originally show normality. Conclusions: The normality of large toxicity dataset was not always satisfactory to the central limit theorem. Normality of those data could be improved through log transformation. Therefore, care should be taken when using toxicity data to induce, for example, mean value for risk assessment.