• Journal of the Korea Convergence Society
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• v.11 no.10
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• pp.377-385
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• 2020

This study aimed to identify the factors associated with distorted body image in adolescents according to sex. The data obtained from the Korea Youth Risk Behavior Web-Based Survey (2019). The subjects included 9,635 adolescents who perceived their body type as overweight, despite having a normal body mass index. The main finding indicated that high levels of fast food consumption were associated with significantly higher feelings of stress, sadness, and despair in both males and females. In addition, both males and females experienced elevated levels of stress, sadness, and despair when they perceived that they were not sufficiently physically active. The results of this study can be used for the development of interventions for adolescents with distorted body image.

• Journal of Ecology and Environment
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• v.40 no.1
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• pp.12-19
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• 2016

Background: Direct impact of inorganic carbon (i.e., carbon dioxide ($CO_2$)) on the periphyton community is important to understand how and to what extent atmospheric conditions can affect the structure and dynamics of these communities in lotic systems. We investigated the influence of elevated $CO_2$ concentration on the periphyton community in the artificially constructed channels during the winter period. The channels made of acrylic paneling were continuously supplied with surface water discharged from a small reservoir, which was supported with ground water, at a flow rate of 5 L/min, and water temperature ranging $4-5^{\circ}C$. The effects of elevated $CO_2$ concentrations (790 ppm) were evaluated in comparison with the control (395 ppm $CO_2$) by analyzing pH, water carbon content and nutrients in water, periphyton composition and biomass, chlorophyll-a, ash-free dry-matter at 2-day intervals for 10 days. Results: After the addition of $CO_2$, significant decreases of pH, $NH_3-N$, and $PO_4-P$ (p < 0.05) and increases of chlorophyll-a, ash-free dry-matter, and the cell density of periphyton (p < 0.01) were observed, whereas the species composition of periphyton and water carbon content did not change. Conclusions: These results suggest that elevated $CO_2$ in flowing water system with low temperature could facilitate the growth of periphyton resulting in biomass increase, which could further influence water quality and the consumers throughout the food web.

• Environmental Analysis Health and Toxicology
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• v.28
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• pp.17.1-17.3
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• 2013

The fact that hazardous metals do not bio-degrade or bio-deteriorate translates to long-lasting environmental effects. In the context of evidently rapid global industrialization, this ought to warrant serious caution, particularly in developing countries. In the Republic of Fiji, a developing country in the South Pacific, several different environmental studies over the past 20 years have shown levels of lead, copper, zinc and iron in sediments of the Suva Harbor to be 6.2, 3.9, 3.3 and 2.1 times more than the accepted background reference levels, respectively. High levels of mercury have also been reported in lagoon shellfish. These data inevitably warrant thorough assessment of the waste practices of industries located upstream from the estuaries, but in addition, an exposure and health impact assessment has never been conducted. Relevant government departments are duty-bound, at least to the general public that reside in and consume seafood from the vicinities of the Suva Harbor, to investigate possible human effects of the elevated hazardous metal concentrations found consistently in 20 years of surface sediment analysis. Furthermore, pollution of the intermediate food web with hazardous metals should be investigated, regardless of whether human effects are eventually confirmed present or not.

• Ocean and Polar Research
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• v.25 no.1
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• pp.21-30
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• 2003

Seasonal fluctuations of physico-chemical and biological aspects of the environment were studied in Vladivostok harbour (Golden Horn Bay, the East Sea/Sea of Japan). The benthic community structure was described with a focus on size-spectra (bacteria, meio- and macrofauna) related with the chemical environment and chemical fluxes in sediment and to reveal their possible ecological role in the process of bioremediation of the environment. Samples from two sites with different concentrations of heavy metals (Fe, Zn, Cu, Pb, Mn, Cr, Ni Cd, Co) and petroleum hydrocarbon were assessed by a number of methods. These included plate counts of culturable bacteria, observation through a scanning electron (SEM) and transmission electron microscope (TEM). These approaches were complemented with microscopic assessments of the diversity of the benthic community. The specific communities had a limited number of species, tolerant to abnormally high levels of toxic compounds. The dominant species were presented by several sho.1-lived small polychaetes (Capitella capitata) and nematodes (Oncholaimium ramosum). The highest population density was recorded in microbenthos, in various diatoms, various physiological groups of bacteria which participate in biomineralization: marine heterotrophic bacteria, which oxidized oil, black oil in addition to groups resistant to heavy metals. They have the entire set of mechanisms for neutralizing the negative effect of those compounds, forming the detrital food web and biogeochemical circulation of material in sediments, which results in the biological self-recycling of sea basins. Macro- and meiobenthic organisms were more sensitive to a greater extent of $H_2S$ and petroleum hydrocarbons than to metal content, but the within-site rankings were the same as those achieved for microbiological analyses.

• The Journal of Korean Society for School & Community Health Education
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• v.14 no.2
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• pp.1-14
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• 2013

Objectives: The purpose of this study was to identify the relationship of internet use time and health risk behaviors among adolescents and provide data to set up a strategy for preventing internet addiction. Methods: The data of the 2011 Youth Health Risk Behavior web-based Survey Collected by Korean Center for Disease Control was analyzed using t-test, ANOVA, Chi-square test for this study. Results: There were significant differences between boys and girls in internet use time. Boy's internet use time was different according to city size(F=13.20, p<.001), grade(F=35.85, p<.001), school record(F=298.95, p<.001), economic state(F=326.75, p<.001), living with parents(t=11.60, p<.001), father's education level(F=147.92, p<.001), and mother's education level(F=110.93, p<.001). Girls' internet use time was also different according to school grade(t=-8.68, p<.001), grade(F=61.03, p<.001), school record(F=233.32, p<.001), economic state(F=185.78, p<.001), living with parents(t=10.81, p<.001), father's education level(F=86.54, p<.001), and mother's education level(F=92.64, p<.001). Regarding the health risk behaviors, present smoking, present alcohol drink, drug use skipping breakfast, eating fast food, drinking soda, sexual behavior, suicidal attempt, engagement time in physical education classes, severe exercise, and sleeping satisfaction made differences in the internet use time. Conclusions: The results suggest that health risk behaviors are influenced by internet use time of adolescents. Thus, these results may be contribute to development of programs to prevent internet addiction.

• The Korean Journal of Ecology
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• v.19 no.6
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• pp.543-562
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• 1996

Zooplankton community structure and the factors correlated with community differences were examined in sandusky Bay (SB) and the open water of Lake Erie (LE, U.S.A.). SB zooplankton communities differed from those in LE by having a greater rotifer density and species richness. Keratella spp., Brachionus spp., and Pompholyx complanata dominated SB rotifers; Brachionus and Pompholyx were rarely seen in LE. Of 19 rotifer species observed, nine species were found only at SB sites. Ordination of zooplankton species abundance by detrended correspondence analysis (DCA) showed an overlap between SB and LE sites, but indicated a portion of the space that was occupied by only SB communities. The seasonal trajectories of zooplankton dynamics in the ordination space at SB sites differed from that of LE. The zooplankton most important in forcing site separation along a DCA Axis I at SB sites were Brachionus angularis, Pompholyx complanata, Keratella valga, Keratella quadrata, Filinia terminalis (rotifers), and Eubosmina coregoni and Daphnia (cladocerans). These species had axis scores which were significantly correlated (p<0.01) with bacterial density and bacterial phosphorus, total phosphorus, and algal density. Very high baterial density and very abundant bacterivorous rotifers in SB suggest that the transport of bacterial carbon through rotifers may be a relatively important link to higher trophic leaels. We believe that this "microbial carbon flow" from the base of the food web may be important in determining the suitability of SB as a spawning site and nursery for larval and juvenile fish.nile fish.

• Journal of Environmental Health Sciences
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• v.31 no.5 s.86
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• pp.431-443
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• 2005

This study was performed to investigate the perceptions of the opinion leaders, such as government officials, researchers, NGO workers, and journalists on the risks of endocrine disrupters (EDs) and genetically modified organisms (GMOs) as well as the related policies on these two hazards or potential hazards. The opinion leaders generally considered the EDs as the most serious hazard among twenty-one environmental health hazards in Korea, and agreed that the EDs would continuously be the most serious hazard. On overall average, the GMOs were ranked the 11th among the twenty-one health hazards. Further investigation indicated that the GMOs were variously ranked by the group of respondents: they were ranked the 2nd by the NGO workers, the 7th by the journalists, the 9th by the researchers and the 11th by the government officials. In general, the respondents considered the dioxin as a hazard with the highest risk while the GMOs were considered less hazardous. The opinion leaders considered that although the risks of the GMOs and EDs were not fully verified, the risks should be controlled through the legislation. The EDs and GMOs should be separately regulated for the time being, while the EDs should put under more strengthened regulation. It is recommended that a web-site containing the information on the EDs and the GMOs be prepared for the journalists. In addition, a training program in relation to the EDs and the GMOs needs to be organized by the Korean Press Foundation and the Korea Food and Drug Administration to educate the journalists. A committee consisting of government officials, scientists, and NGO workers needs to be established, and it should provide framework of future policies and public relations programs.

• Ocean and Polar Research
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• v.35 no.4
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• pp.427-439
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• 2013

Carbon cycling and productivity within Weno Island of Micronesia enclosed by the coral reef may be likely self-maintained and insignificantly affected by the open ocean. Therefore, it is important to understand the role of the mangrove known as providing the organic matter and habitats for many organisms in this enclosed area. In order to trace the nutritional source of fauna (mostly invertebrates) in the mangrove forest of Weno island, we analyzed the fatty acid (FA) and carbon and nitrogen stable isotopes of potential nutritional sources (mangrove leaf & pneumatophore, seagrass leaf & root, surface sediment, and particulate organic matter (POM) in water) and consumers (4 gastropods and anomura). The mangrove and seagrass contained the abundance of 18:2${\omega}$6, and 18:3${\omega}$3, whereas FAs associated with phytoplankton and bacteria were accounted for a high proportion in the surface sediment and POM. FA composition of consumers was found to be similar to those of the surface sediment, mangrove, and seagrass. These were also confirmed through the mixing model of stable isotope for contribution of nutritional sources to consumers. Overall results with the feeding types of investigated mangrove fauna indicate that investigated mangrove fauna obtained their nutrition from the various sources, i.e. the mangrove for Littorina cf. scabra, the microalgae for Strombus sp., and omnivorous Pagurus sp. and Terebralia cf. palustris. However, it is obvious that the nutrition of most species living in the mangrove ecosystem is highly dependent on the mangrove, either directly or indirectly. More detail food-web structure and function of the mangrove ecosystem would be established with the analysis of additional fauna and flora.

• ALGAE
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• v.31 no.1
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• pp.17-31
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• 2016

To explore the feeding ecology of the newly described heterotrophic dinoflagellate Aduncodinium glandula in the family Pfiesteriaceae, its feeding behavior and prey species were investigated. Additionally, the growth and ingestion rates of A. glandula on the mixotrophic dinoflagellates Heterocapsa triquetra and Akashiwo sanguinea, its optimal and suboptimal prey, respectively were measured. A. glandula fed on prey through a peduncle after anchoring to the prey using a tow filament. A. glandula ate all algal prey and perch blood cells tested and had the most diverse prey species in the family Pfiesteriaceae. Unlike for other pfiesteriacean species, H. triquetra and A. sanguinea support the positive growth of A. glandula. However, the cryptophytes Rhodomonas salina and Teleaulax sp. and the phototrophic dinoflagellate Amphidinium carterae did not support the positive growth of A. glandula. Thus, A. glandula may have a unique kind of prey and its optimal prey differs from that of the other pfiesteriacean dinoflagellates. With increasing mean prey concentration, the growth rates of A. glandula on H. triquetra and A. sanguinea increased rapidly and then slowed or became saturated. The maximum growth rates when feeding on H. triquetra and A. sanguinea were 1.004 and 0.567 d⁻¹, respectively. Further, the maximum ingestion rates of A. glandula on H. triquetra and A. sanguinea were 0.75 and 1.38 ng C predator⁻¹ d⁻¹, respectively. There is no other pfiesteriacean species having H. triquetra and A. sanguinea as optimal and suboptimal prey. Thus, A. glandula may be abundant during blooms dominated by these species not preferred by the other pfiesteriacean dinoflagellates.

• 한국해양학회지
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• v.19 no.2
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• pp.172-186
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• 1984

Phyroplankton samples were collected seasonally from March to December, 1982 in order to study the distribution of phyroplankton and their relation to environmental factors in Kwang-yang Bay. A total of 211 taxa of phyroplankton representing 67 genera, 196 species, 14 varieties, and 1 forma have been identified. Seasonal succession of dominant species is evident in this bay; Rhiwosolenia deiicatula, Chroomonas sp. being predominant in spring, Chroomonas sp. in summer, Chaetoceros debilis, C. socialis in autumn, and Skeletonema costatum, Chroomonas sp. in winter, repectively. The standing crops of the phyroplankton vary with time, and hare relevance to NH$\_$3/-N concentration, grazing pressure, and temperature. In spring, diatom blooming is relatively well correlated with the NH$\_$3/-N concentration. The species diversity is rather low in general. The fraction of nanoplankton total cell number represents an annual average of 36.5%, showing a meaningful contribution to the primary production and food web in this water system. Spatial distribution of phytoplankton indicates that this bay could e divided into three chracteristic areas; Seomjin-river mouth area heavily influenced by fresh water, western-half area scarecely affected by the oceanic water, and eastern-half area heavily influenced by the oceanic water. The industrial effluents from the YeochunIndustrial Complex also affected the spatial distribution of phyroplankton.