• 한국환경보건학회지
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• 제41권4호
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• pp.259-267
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• 2015

Objectives: This study evaluated the regional and seasonal concentrations of ambient hazardous heavy metals in an industrial complex area in Daegu City. Methods: A total of 64 SPM (Suspended Particulate Matter) samples were collected in non-industrial and industrial areas during 2014 and were analyzed for hazardous heavy metals elements (As, Cd, Mn, Ni, Pb) with ICP after acid extraction. Results: SPM and hazardous heavy metals concentrations showed regional (industrial complex area>non-industrial complex area) and seasonal (spring, winter>fall, summer) variations. All of the hazardous heavy metals were influenced by anthropogenic sources. The pollution index of hazardous heavy metals was very low, showing roughly one-quarter of the level of the air quality guidelines of WHO. The correlation analysis among SPM and hazardous heavy metals indicated that components of non-industrial complex areas were more related to each other than those of industrial complex areas, and the correlation in the winter was higher than in other seasons. Conclusion: It is necessary to control air pollution sources and establish related policy because hazardous heavy metals from industrial areas can influence residential areas.

• 한국환경농학회지
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• 제41권3호
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• pp.177-184
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• 2022

BACKGROUND: Recently, the inflow of nonpoint pollutants into rivers caused by rapid urban and industrialization promotes the proliferation of algae, which causes eutrophication of rivers. This study was conducted to evaluate the seasonal variation of water quality characteristics and cryptomonads growth in the Oncheon River. METHODS AND RESULTS: The water quality and distribution characteristics of cryptomonads in the Oncheon River were investigated monthly for 12 months from January 2021. The cell number of cryptomonads was intensively developed in January-April, and it decreased sharply in the summer with heavy rainfall. In particular, cryptomonads moved to the downstream side of the river depending on the time, and as a result, significant differences were shown for each investigation point. The Korean trophic state index (Tsi_KO) in Oncheon River was classified as eutrophy all year round, indicating that cryptomonads can grow year-round. Distribution characteristics of cryptomonads in Oncheon River showed high correlations with DO (r=0.678), BOD (r=0.826) and chlorophyll-a (r=0.613) in water. CONCLUSION(S): In order to reduce cryptomonads in the Oncheon River, it is judged that a complex countermeasure considering the residence time, insolation and precipitation along with water quality factors is required.

• Fisheries and Aquatic Sciences
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• 제26권8호
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• pp.482-490
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• 2023

Food and feeding habits of Labeobarbus intermedius were studied from the newly constructed Ribb Reservoir, Ethiopia during the dry (December-March) season and wet season (June-August) of 2021. The objective of the study was to determine the diet composition, seasonal variation, and ontogenetic dietary shift in the diets of the dominant cyprinid fish in Ribb Reservoir. In this study, frequency of occurrence and volumetric analysis methods were used to present the results. From a total of 203 fish samples, 132 (65%) guts contained food items. Macrophytes (29.4%), phytoplankton (27.2%), detritus (14.8%), and insects (13.6%) were the major food items in the diets volumetrically. During the dry season, L. intermedius was mainly dependent on phytoplankton (58.2%), insects (15.2%), and zooplankton (13.7%) volumetrically. Whereas, macrophytes (50.3%) and detritus (23.3%) were the dominant food items in the wet season. The frequency occurrence and volumetric contribution of the diets of L. intermedius varied significantly (χ² test, p < 0.05) between seasons. Schoener's diet overlap index revealed a slight ontogenetic dietary shift in the diets of L. intermedius. While insects, nematodes, and zooplankton were the main diets of small-sized L. intermedius, macrophytes and detritus were ingested by large-sized L. intermedius. Generally, L. intermedius fed both plant and animal-origin food items and is considered an omnivorous feeder in Ribb Reservoir.

• Journal of Korean Society for Atmospheric Environment
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• 제24권E2호
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• pp.74-82
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• 2008

We have examined seasonal and annual means of clear-sky solar noon and daily erythemal ultraviolet-B irradiances measured in Anmyeon. The intensity of the EUV-B irradiance is mainly dependent on solar zenith angle (SZA) and total ozone amounts on clear day conditions. The daily maximum occurs near solar noon time and the highest monthly accumulated EUV-B is seen in July in Anmyeon. The maximum daily variation occurs in June and July due to precipitation and clouds. The 7-year trend of EUV-B irradiance shows that it is slightly increasing. Additionally, we could confirm that aerosol effects such as Asian Dust decreases the EUV-B irradiance reaching the ground surface by 35% to 60%. For more than 45% of the summer days, EUV-B irradiacne was high enough that the UV index registered higher than category Extremely High. This information will be very important for evaluation of the UV index for prevention of both skin cancer and ecosystem damages as well as to understand UV climatology over the Korean Peninsula.

• 통합자연과학논문집
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• 제15권3호
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• pp.111-122
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• 2022

The purpose of this study was to investigate the ecological impact of wetlands by changing the species diversity of benthic macroinvertebrates and birds following the creation of an artificial wetland with a size of 30 m*30 m on bare land in reclaimed land in Haenam-gun, Korea. We investigated monthly fauna of benthic macroinvertebrates and birds in and outside wetlands and physicochemical indicators for 7 months from March to September 2014. During the study period, the water temperature and dissolved oxygen levels were consistently higher in wetlands than lakes. Many species of benthic macroinvertebrates were observed in summer (16 species in July) due to seasonal effects, and the species diversity index was highest in July and then gradually decreased. Thirteen species of birds were observed in March, 6 species in April, 5 species in July, and 1 species in June, where most winter birds and migratory birds were observed around wetlands in spring. The species diversity index also decreased after being high in July except for spring. This suggests that the abiotic environment in the wetland can be improved by creating an artificial wetland in the reclaimed land, and the increase in benthic macroinvertebrates can ultimately be a basic direction to restore the wetland ecosystem in the reclaimed land.

• 한국수산과학회지
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• 제49권3호
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• pp.385-392
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• 2016

Seasonal variability in the algal community structure of intertidal zones was examined at six study sites in Marine National Parks, on the western and southern coasts of Korea from March to November 2015. A total of 193 species of algae, comprising 27 green, 40 brown and 126 red algae, were identified. Algal biomass averaged 101.50 g dry wt./m² with a maximal at Tonggae (168.12 g dry wt./m²) and minimum at Haseom (54.49 g dry wt./m²). The dominant seaweeds by biomass were Sargassum thunbergii at five sites (Tonggae, Haseom, Namdongri, Ando amd Sinjeonri), and S. fusiforme at Soando. Community indices measured as follows: dominance index (DI), 0.31–0.69; richness index (R), 7.30–11.43; evenness index (J'), 0.33–0.49; and diversity index (H'), 1.15–1.86. As evaluated using community indices and environmental states, the EEI (Ecological Evaluation Index) of the Marine National Park was “normal”. The present results indicate that seaweed community structures and indices could be used to evaluate the environmental status of coastal ecosystems.

• 한국환경과학회지
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• 제28권12호
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• pp.1133-1145
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• 2019

Successful launch requires state-of-the-art launch vehicle technology and constant test operations, However, the meteorological threat to the launch vehicle flight trajectory is also an important factor for launch success. Atmospheric stability above the Naro Space Center at the this time is very important, especially because the initial flight operation can determine the success of the launch. Moreover, during the flight of launch vehicle with rapid pressure and thrust into the atmosphere, convection activity in the atmosphere may create environmental conditions that cause severe weather threats such as thunderstorms. Hence, studies of atmospheric instability characteristics over the Naro Space Center are a necessary part of successful launch missions. Therefore, the main aims of this study were to (1) verify the atmospheric stability index and convection activity characteristics over the Naro Space Center using radiosonde data observed from 2007 to 2018 by the Naro Space Center, (2) analyze changes in the atmospheric stability index according to monthly and seasonal changes, and (3) assess how the calculated atmospheric stability index is related to actual thunderstorm occurrence using statistical analysis. Additionally, we aimed to investigate the atmospheric characteristics above the Naro Space Center through the distribution chart of the atmospheric stability index during summer, when convection activity is highest. Finally, we assessed the relationship between lightning occurrence and unstable atmospheric conditions, through predictability analysis performed using the lightning observation data of the Korea Meteorological Administration.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권4호
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• pp.14-27
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• 2020

The drought has occurred from the past, and has caused a lot of damage. It is important to analyze the past droughts and predict them in the future. In this study, the temperature and precipitation of the past and the future from climate change RCP 4.5 and 8.5 scenarios were analyzed for Seosan and Boryeong in the western region of Chungnam Province, which is considered as a drought-prone area on the Korean Peninsula. Comparing Standardized Precipitation Index (SPI) and Effective Drought Index (EDI) based on the past droughts, EDI was verified to be more suitable for the drought assessment. According to RCP 4.5, the frequency and intensity of droughts in the early future (2021~2060) were expected to increase and to be stronger. Particularly, severe droughts were predicted for a long time from 2022 to 2026, and from 2032 to 2039. Droughts were expected to decrease in the late future (2061~2100). From RCP 8.5, drought occurrences were predicted to increase, but the intensity of the droughts were expected to decrease in the future. As a result of evaluation of the frequencies of droughts by seasons, the region would be most affected by fall drought in the early future and by spring drought in the late future according to RCP 4.5. In the case of RCP 8.5, the seasonal effects were not clearly distinguished. These results suggest that droughts in the future do not have any tendency, but continue to occurr as in the past. Therefore, the measures and efforts to secure water resources and reinforcement of water supply facilities should be prepared to cope with droughts.

• The Korean Journal of Ecology
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• 제16권2호
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• pp.209-227
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• 1993

Aquatic insects were collected from 18 sites in the Yongsan River System from August, 1988 to July, 1989. The monthly fluctuation and distributional pattern of the aquatic insects along the environmental factors were investigated. Quantitatively collected aquatic insects were identified, and numbers, standing biomass, dominance indices and diversity indices in each site and month were determined. The aquatic insect faun of the Yongsan River System was composed of 146 species, 82 genera, 38 families in 7 orders including 44 species of mayflies, 32 species of caddisflies, 24 species of stoneflies, 21 species of flies, 16 species of beetles, 6 species of dragonflies and 3 species of dobsonflies. Seasonal occurrence of species were more diversified in winter and spring than in summer. Also, the number of individuals occurred was higher in winter and spring than in summer while it was the highest in upper stream and the lowest in Kwang-ju stream. Component ratio of the number of individuals according to the insect orders was as follows: Mayflies 38.71%, Flies 36.97%, Stoneflies 10.21%, Caddisflies 6.80%, Beetles 2.96%, Dobbsonflies 2.74%, Dragonflies 0.95%. Percentage of standing biomass according to insect orders were as follows: Mayfiles 32.81%, Stoneflies 26.51%, Caddisflies 17.58%, Dobbsonflies 14.84%, Flies 3.74%, Beetles 3.08%, Dragonflies 1.45%, The highest standing biomass occurred in spring and the lowest in summer.

• ALGAE
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• 제27권4호
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• pp.269-281
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• 2012

Marado is a small rocky island located off the south coast of Jeju Island and acts as the first gateway of the Kuroshio Current to Korean coastal ecosystems. This island is one of the most unpolluted and well preserved sea areas around the Jeju coast. We extensively observed macroalgal assemblages of species and functional forms in the intertidal and subtidal zones through four seasons on Marado, Jeju Island, Korea to demonstrate the seasonality of vertical distribution patterns and biomass. A total of 144 species (14 Chlorophyta, 40 Phaeophyta, and 90 Rhodophyta) were identified in quadrats and were analyzed seasonally and vertically to define the variation patterns. The annual mean biomass of macroalgae was $2,932.3g\;wet\;wt\;m^{-2}$ and the highest value was recorded in spring and the lowest was in winter. The annual dominant species by biomass was Ecklonia cava followed by Sargassum fusiforme, S. macrocarpum, Amphiroa galapagensis, Chondria crassicaulis, and S. thunbergii. Obvious biomass zonation patterns of macroalgal species were detected in relation to tidal height and depth. Macroalgal biomass, diversity index (H'), and community dynamics were the highest in the shallow subtidal zone. Species number was higher in the subtidal than in the intertidal zone and similar throughout the entire subtidal zone. Our results provide revealing insights into the distribution patterns of macroalgal assemblages in an unpolluted sea area around Jeju Island.