• Journal of Soil and Groundwater Environment
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• v.28 no.5
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• pp.68-77
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• 2023

The effect of soil damage on the physicochemical characteristics and activity of the soil microbial community is not well known. This study investigates this relationship by analyzing 11 soil samples collected from various points of soil damage across Gyeonggi-do. Soil damage resulted from forest fires, landslides, and development areas, with their impacts most severe on the topsoil layer (0-30 cm). Dehydrogenase and β-glucosidase activities were notably higher at locations damaged by forest fires compared to other sites. While enzyme activities in soils influenced by landslides and development areas were relatively low, sites with a pollution history exhibited elevated dehydrogenase activity, likely due to past microbial response to the pollution. Additionally, an assessment of carbon substrate usability by soil microorganisms indicated higher substrate availability in areas impacted by forest fires, contrasting with lower availability in landslide and development sites. Statistical analysis revealed a positive correlation between organic content of sand and clay and microbial activity. These findings provide valuable insights into soil damage and associated restoration research, as well as management strategies.

• New & Renewable Energy
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• v.20 no.1
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• pp.145-174
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• 2024

Addressing climate change necessitates evidence-based policies grounded in science. The use of forest biomass for energy production is based on a broad scientific consensus at the international level. However, some environmental groups in South Korea are opposing this system of energy production. Through this study, the authors aim to reduce unnecessary confusion and foster an atmosphere conducive to meaningful evidence-based policies. We have classified the issue into eight categories: biological carbon cycle, carbon debt, nature-based solutions, air emissions, cascading principles and sustainability certification, forest environmental impacts, climate change litigation, and the behavior of environmental groups and public perception. Consequently, the following key points were derived: (1) the actions of some environmental groups seem to follow a similar pattern to denialist behavior that denies climate change and climate science; (2) the quality of evidence for campaigns that oppose the use of forest biomass for energy production is low, with a tendency to overgeneralize information, high uncertainty, and difficulty in finding new claims.; (3) most of the public believes that forest biomass energy is necessary, and the governments of major countries are aware of its importance. Significantly, Forest biomass for energy is based on an overwhelming level of scientific consensus recognized internationally.

• ALGAE
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• v.22 no.4
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• pp.287-295
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• 2007

Infection of free-living dinoflagellates by endoparasitic dinoflagellates of the genus Amoebophrya are thought to have significant impacts on host population dynamics and have long been proposed to be a potential biological agent for controlling harmful algal bloom (HAB). To understand the impact of Amoebophrya on particular host species, however, it is necessary to quantify aspects the parasites life cycle. Here we used cultures of Amoebophryahost systems from Jinhae Bay, Korea to determine, parasite generation time, and dinospore survival and infectivity. The proportion of host cells infected by Amoebophrya sp. changed sharply from 5% to 87% with increasing dinospore:host inoculation ratios. In the absence of H. triquetra, most free-living dinospores died within 72 hours and their ability to infect host cells decreased remarkably in a day. The relatively short free-living phase of Amoebophrya suggests that the spread of infections is most likely to occur during seasons of high host abundance, as that is when dinospores have the greatest chance of encountering host cells. Infection of host cells inoculated with dinospores during the day was higher than when inoculated during the night, suggesting that infection rates might be related to environmental light conditions and/or diurnal biological rhythm of host species. Total generation times of parasite strains from a thecate dinoflagellate Heterocapsa triquetra were nearly the same regardless of dinospore:host inoculation ratios, representing 54 ± 0.5 h in a 1:1 ratio and 55 ± 1.2 h in a 20:1 ratio. Dinospore production of Amoebophrya sp. infecting Heterocapsa triquetra was estimated to be 125 dinospores per a strain of Amoebophrya sp. There is a growing need to maintain a variety of host-parasite systems in culture and to examine their autecology under various environmental conditions. Such studies would be very helpful in understanding ecological role of these parasites, their overlooked importance in the flow of material and energy in marine ecosystem, and their practical use as biological control agents applied directly to areas affected by HAB.

• Science of Emotion and Sensibility
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• v.21 no.3
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• pp.151-164
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• 2018

The appropriate interpretation of social cues is a crucial ability for everyday life. While processing socially relevant information, beyond the low-level physical features of the stimuli to emotional information is known to influence human cognition in various stages, from early perception to later high-level cognition, such as working memory (WM). However, it remains unclear how the influence of each type of emotional information on cognitive processes changes in response to what has occurred in the processing stage. Past studies have largely adopted face stimuli to address this type of research question, but we used a unique class of socially relevant motion stimuli, called biological motion (BM), which depicts various human actions and emotions with moving dots to exhibit the effects of anger, happiness, and neutral emotion on task performance in perceptual and working memory. In this study, participants determined whether two BM stimuli, sequentially presented with a delay between them (WM task) or one immediately after the other (perceptual task), were identical. The perceptual task showed that discrimination accuracies for emotional stimuli (i.e., angry and happy) were lower than those for neutral stimuli, implying that emotional information has a negative impact on early perceptual processes. Alternatively, the results of the WM task showed that the accuracy drop as the interstimulus interval increased was actually lower in emotional BM conditions than in the neutral condition, which suggests that emotional information benefited maintenance. Moreover, anger and happiness had distinct impacts on the performance of perception and WM. Our findings have significance as we provide evidence for the interaction of type of emotion and information-processing stage.

• Microbiology and Biotechnology Letters
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• v.46 no.3
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• pp.181-193
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• 2018

Nitrous oxide ($N_2O$) is a potent greenhouse gas as well as an ozone-depleting substance. $N_2O$ is emitted during the biological nitrogen removal process in wastewater treatment systems (WTSs), and has significant environmental impacts. In this study, $N_2O$ emission in WTSs was comprehensively reviewed to better understand the effects of key parameters on $N_2O$ emission and obtain useful guidelines for $N_2O$ mitigation strategies in WTSs. Three biological pathways leading to $N_2O$ emission are hydroxylamine oxidation, nitrifier denitrification, and heterotrohic denitrification. Measurements at lab-, pilot- and full-scale WTSs have shown large variations in $N_2O$ emission (0-95% of N-loaded) during wastewater treatment. In the full-scale WTSs (0-14.6% $N_2O$ of N-loaded), the average and median values were 1.95% and 0.2% of N-loaded, respectively. Dissolved oxygen, nitrite concentrations, and chemical oxygen demand (COD)/N ratio are the most important parameters leading to $N_2O$ emission. A variety of operational strategies have been suggested to minimize $N_2O$ emission from WTSs. A new $N_2O$ mitigation strategy involving the introduction of microorganisms with high $N_2O$ reductase activity or oxygenic denitrification ability has been proposed as an alternative canonical denitrification.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2699-2705
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• 2014

This study was to undertaken to investigate the impacts of AhR, CYP1A1, GSTM1 genetic polymorphisms on the R273G mutation in exon 8 of the tumor suppressor p53 gene (TP53) among polycyclic aromatic hydrocarbons (PAHs) exposed to coke-oven workers. One hundred thirteen workers exposed to PAH and 82 control workers were recruited. We genotyped for polymorphisms in the AhR, CYP1A1, GSTM1, and TP53 R273G mutation in blood by PCR methods, and determined the levels of 1-hydroxypyrene as PAH exposure marker in urine using the high pressure liquid chromatography assay. We found that the distribution of alcohol users and the urinary excretion of 1-OHP in the exposed workers were significantly higher than that of the control workers (p=0.004, p<0.001, respectively). Significant differences were observed in the p53 genotype distributions of smoking subjects (p=0.01, 95%CI: 1.23-6.01) and PAH exposure (p=0.008, 95%CI: 1.24-4.48), respectively. Further, significant differences were observed in the p53 exon 8 mutations for the genetic polymorphisms of Lys/Arg for AhR (p=0.02, 95%CI: 0.70-15.86), Val/Val for CYP1A1 (p=0.04, 95%CI: 0.98-19.09) and null for GSTM1 (p=0.02, 95%CI: 1.19-6.26), respectively. Our findings indicated that polymorphisms of PAH metabolic genes, such as AhR, CYP1A1, GSTM1 polymorphisms may interact with p53 genetic variants and may contribute to PAH related cancers.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.69-81
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• 2010

This study was conducted at 25 sites of 6 mainstreams and 19 tributaries sites within Heuck Stream watershed during May~October 2003 for the survey of fish distributions, compositions, and community characteristics. The survey showed that total fish was identified as 9 family and 26 species in all sites, and Cyprinidae dominated the community as 15 species. The dominant species of >20% of the total were Zacco temminckii (29%), Zacco platypus (22%), and Rhynchocypris oxycephalus (21%) in the watershed. Community analysis, based on the stream spatial gradients, indicated composition differences along the main axis of the stream from the headwater to the downstream; R. oxycephalus predominated in the most headwater zone and Z. temminckii dominated in the lower headwater zone, whereas Z. temminckii -Z. platypus dominated in the mid-to-downstream, and Z. platypus dominated the community in the most downstream zone. Total endemic species was 7 family and 15 species, which is made of 50% in the fish community, so that the high proportion of endemic species indicated a healthy region in terms of fish community, compared to average 23% in Korean peninsula in general. The total number and species of fish increased as the stream order (stream size) increased, indicating that impacts on chemical pollution or habitat disturbance were not so large to the fish community in this watershed. Trophic and tolerance guilds analysis showed that relative proportions of sensitive and insectivore species were >50% in the watershed and decreased as the stream order increased, whereas relative proportions of tolerant and omnivore species showed an opposite results. These outcomes suggest that the natural condition of watershed is preserved relatively and the region should be protected from the chemical and habitat disturbace by agricultural activity and urban developments.

• The Korean Journal of Ecology
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• v.28 no.1
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• pp.37-43
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• 2005

This study presents the Mid-Lateglacial vegetation history of southwestern Korea. From the result of AMS dating and pollen analysis, four local pollen assemblage zones(BS) were recognized. The four local pollen assemblage zones are BS 1. 12,222cal BC$\sim$9,160cal BC: cool-temperate northern/altimontane mixed coniferous & deciduous broad-leaved forest, BS 2. 9,160cal BC$\sim$ 4,210cal BC: cool-temperate central/montane deciduous broad-leaved forest, BS 3. 4,210cal BC$\sim$125cal BC: cool-Temperate southern/submontane mixed coniferous & deciduous broad-leaved forest. BS 4. BC125cal ${\sim}$present: warm-temperate/cool-temperate southern/submontane coniferous forest. Pine forest expanded since 4,210cal BC and full-scale rice cultivation might started since 2,120cal BC. A radical expansion of Pinus densiflora forest after postglacial stage might be caused by human impacts including full-scale agriculture.

• Journal of Wetlands Research
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• v.26 no.2
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• pp.160-167
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• 2024

The amphibians serve as environmental indicator species warning of threats from pollution and development, and information regarding their body condition and surrounding habitat can be utilized as crucial indicators for assessing ecosystem health. The objective of this study was to investigate the differences in body condition and the climate environments according to the season and sex of Class II endangered Kaloula borealis. A total of 53 surveys were conducted from June to October 2018, targeting frogs inhabiting the Godeok-dong area of Gangdong-gu, Seoul. Using the weight and length of each individual, the body condition index (SMI, Scaled mass index) was calculated. Results showed a total capture of 396 individuals, consisting of 235 males and 161 females. Females exhibited longer SVL and greater weight compared to males, with higher body condition indices. Monthly body condition indices were lower for males in June, while no differences were observed between males and females from July to September. Among the climate environments where females and males appeared, environmental variables related to precipitation and humidity showed differences. These research findings are deemed crucial for providing fundamental information to ascertain suitable habitats for Kaloula borealis and selecting alternative habitats due to developmental impacts in the future.

• Ocean and Polar Research
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• v.28 no.2
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• pp.129-144
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• 2006

Small-scale effects of sand mining on macrobenthic communities have been reported previously. However, little information is available as to how dredging affects the macrobenthic community structure. The objective of this study was to determine the impacts of large-scale exhibition dredging on the macrobenthic community of Gyeonggi Bay, Korea, where sand mining has continued for 20 years. Prior to dredging, the macrobenthic species composition was similar to that of areas near the dredging site, with several common dominant species found before dredging. After dredging, the number of species, density, and diversity (H') in the experimental area (sites 0 and 1) decreased significantly, but no difference was observed at other sites. Multivariate analysis (multidimensional scaling) revealed significant differences in community structure before and after dredging. The amphipod Urothoe grimaldii japonica, which was the most dominant species at sites 0,1, and 2, decreased rapidly at sites 0 and 1 after dredging, but no difference was observed at site 2. In addition, the index of multivariate dispersion (IMD) and the relative IMD (r. IMD) were large at sites 0 and 1, suggesting that the effects of dredging were direct at site 0 and 1, but indirect at site 2. The macrobenthic communities at sites 3 and 4 were not affected by dredging, but they were affected by physical conditions and biological interactions. We suggest that benthic biotope indices such as the IMD and r.IMD may constitute a valid tool for assessing the effects of dredging on the macrobenthic community; long-term monitoring is required to verify this.