• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.3
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• pp.77-86
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• 2005

A monitoring study has been conducted to identify hydrologic conditions, water quality and nutrient loading characteristics of small watershed in Juam Lake. Climate data of the watershed were collected; flow rate was measured and water quality sampling was conducted at the watershed outlet for this study. Water quality data revealed that T-P concentrations meet I grade of lake water quality standard during non-storm period, but degraded up to II-III grade of lake water quality standard during storm period. The observed T-N concentrations always exceeded lake water quality standard. Therefore, T-P was identified as limiting chemical constituent for eutrophication of Juam Lake. T-P concentration of non-storm period also revealed that point source pollution is not serious in the watershed. Three year monitoring results showed that the observed T-N losses were $10.85\~18.88$ kg/ha and T-P losses were $0.028\~0.323$ kg/ha during six month (Mar. - Oct.), respectively. Major portion of runoff amount discharged by a few storm events a year and nutrient load showed apparent seasonal variation. Huge runoff amounts were generated by intense storms, which make application of water treatment or detention facilities ineffective. Monitoring results confirmed that water quality improvement by abating nonpoint source pollution in rural watershed of monsoon climate should be focused on source control. T-P losses from paddy field seemed to consist of significant amount of total load from study watershed. Therefore, management of drainage from paddy field is considered to be important for preventing algal blooming problem in Juam Lake.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.1
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• pp.1-8
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• 2013

This study was conducted to compare the local climate conditions and growth periods for the apple (Malus domestica 'Borkh') orchards at different altitudes (330, 500, and 670 m) in Jangsu-Gun, Korea. Observation data for the growth period show that the monthly mean air temperatures at the 'Hongro' apple orchard sites decrease with height at the rate of 1.0 to $3.0^{\circ}C$/100 m. The monthly minimum temperatures in April (blooming period for 'Hongro' apple) were 4.3, 2.9, and $0.4^{\circ}C$ at 330, 500, and 670 m, respectively. The monthly mean temperatures in September (i.e., the coloration and maturation period) were 20.6, 18.7, and $14.5^{\circ}C$, respectively. The annual precipitation range varied from 1,234 to 1,439 mm, which tended to increase with height. The heavy rainfall occurred in summer (June to August) and amounted to 827-933 mm. No significant differences in the duration of sunshine were observed amongst the orchards at three different altitudes. The earliest bud break was observed at the 330 m altitude (18 March 2009), which was 4 and 11 days earlier in comparison to those at 500 and 670 m, respectively. The time of full bloom at 330 m was 12 days ahead of that at 670 m. The optimal maturation of fruit (based on skin redness > 80%) was observed between 7 and 10 September at 330 m, 15 and 18 September at 500 m, and 21 and 23 September at 670 m.

• ALGAE
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• v.19 no.3
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• pp.227-234
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• 2004

A study on the dynamics of phytoplankton community and the physico-chemical environmental factors was performed biweekly from April 1998 to March 1999 in Youngchun Dam. A total 72 phytoplankton taxa was identified and dominant taxa were blue-green algae and diatoms. The highest value of phytoplankton standing crop (24,826cells·ml$^{-1}$) was observed in September 7, 1998, the blooming period of blue-green algae Phormidium sp., while the lowest (318cells·ml$^{-1}$) was measured in June 18, 1999. The phytoplankton communities were dominated by blue-green algae of Anabaena planktonica, Microcystis aeruginosa and Phormidium sp. during the summer and autumn periods and were dominated by diatoms of Synedra acus and Aulacoseira spp. during the spring and winter periods. Secchi disc transparency, chlorophyll-a, total nitrogen, total phosphorus and silicate concentration were varied in the ranges of 0.4-2.5 m, 2.4-32.2mg·m$^{-1}$, 0.845-2.352mg·l$^{-1}$, 0.005-0.093mg·l$^{-1}$, 0.2-15.7mg·l$^{-1}$, respectively. The trophic status of Youngchun Dam were estimated eutrophic according to Lake Trophic States Index (LTSI).

• ALGAE
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• v.23 no.1
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• pp.31-52
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• 2008

This study analyzes characteristics of phytoplankton communities around Wolseong nuclear power plant by selecting 16 stations from July 2006 to June 2007 and understands the influences on standing crops and chlorophyll a of phytoplankton by passing through the cooling water system. The total species number is 283, among which diatoms is 208 occupying 73.5% of total taxa. The mean of total standing crops is 469,380-3,704,114 cells L-1. It is the highest in April 2007 because blooming of Chaetoceros socialis occurs during this period. The mean standing crops of microplankton and nanoplankton are average 129,666-3,392,640 cells L-1 and 240,943-650,505 cells L-1 respectively, which occupy 54.01% and 46.54% of total standing crops. The mean concentrations of total chlorophyll a is 0.64-5.39 μg L-1. The mean concentrations of chlorophyll a of microplankton, nanoplankton and picoplankton are 1.33 μg L-1, 0.21 μg L-1 and 0.49 μg L-1 respectively. Dominant species around Wolseong neclear power plant during this study are Chaetoceros debilis, Chaetoceros socialis, Leptocylindrus danicus, Pseudo-nitzschia fraudulenta, P. subfraudulenta and Thalassiosira decipiens. Fluctuation rates of standing crops and chlorophyll a concentrations of phytoplankton passing through the cooling water system are 22.80% and 50.48% respectively. Decrease of standing crops and chlorophyll a concentrations of phytoplankton means that community structure of phytoplnakton may change at the discharge areas.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.375-380
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• 2003

For some decades eutrophication poses a great problem in water quality management in fresh-waters. To solve this problem, studies based on "bottom-up" hypothesis have been mostly carried out worldwidely unlike biomanipulation. This implies that not only fish but also fish stock playa key role down to other food web components in pelagic ecosystem. It is generally accepted that biomanipulation becomes a potent tool for eutrophication control. For a practical application of this, however, further development and understanding of the food web under the specific lake condition on a whole-lake scale are needed. The question is how can we maintain the positive effects resulted from biomanipulation (fortuitous or planned) for a long period.

• Journal of Environmental Science International
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• v.4 no.5
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• pp.95-95
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• 1995

This study was carried out to evaluate the variations of headloss rate and of specific deposit to depths with effective size of media and configuration of filter layer during algae blooming period. 0.51mm size media was disqualified because most of headloss occurred rapidly below 5cm from surface layer however 0.91mm size media acted deep filtration more than 20cm from top, as result 0.91mm sixte media filter had 2∼3 times longer filtration time than 0.51mm sixte media filter, but 0.91mm size media have break-through potentiality. multi-layer filter with 1.02mm anthracite and 0.51mm sand had large deposit volume in upper layer that could longer filtration time, moreover smaller media in lower layer that could protect break-through.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.5
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• pp.59-69
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• 2013

Global warming also has effects on the phenology. The limitation of phenology study is an acquisition of phenology data. Satellite images analysis can make up limitation of monitering data. This study is to analyze spatial distribution and characteristics of phenology changes using MODIS images. Research data collected images of 16 day intervals of 11 years from year 2001 to 2010. The data analyzed 228 images of 11 years. It can figure out changes of phenology by analyzing enhanced vegetation index of MODIS image. We made a comparison between changes of phenology and flowering of cherry blossoms. As a results, Startup of season spatially was getting late from southern area to north area. Startup of Phenology was foreshortened 13 days during 11 years, and change ratios of cherry blooming was getting more faster from 0.18 dat to 0.22 day per year during that same period.

• The Korean Journal of Ecology
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• v.14 no.1
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• pp.25-38
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• 1991

Berchemia berchemiaefolia is a native a native rare plant which has been designating as the Natural Monument, No. 266, since 1980. The floristic composition, population structure and maintenance mechanism of the Berchemia berchemiaefolia forest were investigated in conjunction with the habitat consisted of the block field or screes. Through the present study, the authors found a new habitat of Berchemia berchemiaefolia in the northeastern slope on Mt. Kumdansan located at Hajeok-ri, Cheongcheon-myeon, Koesan-gun, chungbuk province. Gravels consisted of the block field belonged to granule, pebble and cobble as the range of grain size, $\Phi$=-1.5~6.6 values. The tree layer of Berchemia berchemiaefolia community was mainly composed of Quercus variabilis, Pinus densiflora and Q. serrata including Berchemia berchemiaefolia and of this community were similar to that of Q. variabilis. By the age distribution, it was considered that the community was a discontinued one as the pattern of distribution was a normal distribution type(N type). Phenological cycle including leafing, blooming and seed-bearing period between both sites of block field and valley or close canopy showed some differences. The seed production of Berchemia berchemiaefolia was 8, 655, 000 seeds/ha/year, but only 406, 000 seeds/ha/year of them were developed as saplings, and only 4 saplings were developed to mature trees.

• Journal of Species Research
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• v.10 no.2
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• pp.159-163
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• 2021

Saussurea albifolia, a new species, is reported from the Baekdudaegan Mountains. It has distinctive morphological characteristics that distinguish it from other congeneric species of Saussurea in Korea; radical leaves persist or withered till flowering, white tomentose leaf beneath, campanulate involucre with brown-cobwebby hairs, and dark purplish phyllaries with acuminate tips. Saussurea albifolia is a new, endemic species, narrowly restricted to the Korean Peninsula as a consequence of adaptation to alpine or subalpine environments of the Baekdudaegan Area. Among the Korean species of Saussurea, S. gracilis Maxim., S. insularis Kitam., and S. seoulensis Nakai are morphologically similar to S. albifolia by having leaves with white hairs beneath and persistent radical leaves during blooming period. It has been well understood that Saussurea is one of the highly diversified and adaptable groups in Asteraceae and also that the currently recognized species in Korea likely significant underestimates its diversity on the Korean Peninsula.

• Journal of Ecology and Environment
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• v.46 no.1
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• pp.18-30
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• 2022

Background: Bees and flowering plants associations were initially began during the early Cretaceous, 120 million years ago. This coexistence has led to a mutual relationship where the plant serves as food and in return, the bee help them their reproduction. Animals pollinate about 75% of food crops worldwide, with bees as the world's primary pollinator. In general, bees rely on flower scents to locate blooming flowers as visual clue is limited and also their host plants from a distance. In this review, an attempt is made to collect some relevant 107 published papers from three scientific databases, Google Scholar, Scopus, and Web of Science database, covering the period from 1959 to 2021. Results: Flowering plants are well documented to actively emit volatile organic compounds (VOCs). However, only a few of them are important for eliciting behavioral responses in bees. In this review, fifty-three volatile organic compounds belonging to different class of compounds, mainly terpenoids, benzenoids, and volatile fatty acid derivatives, is compiled here from floral scents that are responsible for eliciting behavioral responses in bees. Bees generally use honest floral signals to locate their host plants with nectar and pollen-rich flowers. Thus, honest signaling mechanism plays a key role in maintaining mutualistic plant-pollinator associations. Conclusions: Considering the fact that floral scents are the primary attractants, understanding and identification of VOCs from floral scent in plant-pollinator networks are crucial to improve crop pollination. Interestingly, current advances in both VOCs scent gene identification and their biosynthetic pathways make it possible to manipulate particular VOCs in plant, and this eventually may lead to increase in crop productivity.