• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.234-243
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• 2007

Algal growth potential (AGP) test was performed to evaluate the water quality and changes in phytoplankton communities before and after a heavy rain event at six sampling sites in Cheonggye Stream (St. 1 and 2), Jungnang Stream (St. 3 and 4), and Lower part of Han River System (St. 5 and 6) after rehabilitation of Cheonggye Stream, October 2005. To test AGP on each sampling site, cyanobacterium Microcystis aeruginosa was applied as a standard alga. Total nitrogen (TN) showed high values at Jungnang Stream, while St. 4 recorded highest values in this study. However, TN values of Cheonggye Stream and Lower Part of Han River showed similar levels. Total phosphate (TP) also showed high values at Jungnang Stream, while St. 4 recorded highest. However, TP in Cheonggye Stream were extremely low levels. Although chlorophyll-${\alpha}$ (chi-${\alpha}$) contents before the rain event were similar through the sampling sites, chl-${\alpha}$ after the rain increased dramatically at Jungnang Stream and Lower part of Ban River. In particular, after the rain, TP was the highest at St. 4, where Cyclotella sp. dominated the phytoplankton community. When compared with control, AGP values before the rain were comparatively low in all sites, while those after the rain highly increased with the dose-dependently of field water added, due perhaps to the increased nutrients by rainfall. Similar results were observed in Cheonggye Stream. Therefore, for the aesthetic fostering for the citizens, although Cheonggye Stream was Presently being sustained by treated water supply, they have a potential of outbreak of phytoplankton by the increased nutrients supply when a heavy rain comes.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.293-305
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• 2019

In this study we investigated the effect of a floating photovoltaic (FPV) system in Cheongpung Lake on water quality. The FPV with a tilt angle of 33° covered ca. 0.04% of surface area (97 ㎢) of Chungju Lake. The water qualities of the whole lake before and after installation of FPV were first compared. DO, BOD, TOC, and Chl-a of the whole lake were increased, while conductivity decreased after installation period at the significance level of 0.05. This change was probably due to the increased influx of nutrients by 40% resulting from increased precipitation during the same period. We also measured water quality parameters on May and Nov. 2017 at the FPV center (FPVC) and nearby control sites, and compared water quality. The result showed that the FPVC and nearby sites were not significantly different (p>0.05), demonstrating that the FPV does not cause a decline of water quality. The water temperature, light intensity, and phytoplankton community were also measured. The water temperature was not different between the sites, while the light intensity decreased to 27~50%. Despite reduced light intensity at FPVC, the phytoplankton standing crops and the number of species were not significantly different (p>0.05). However, in the early November samples, standing crops was significantly higher in FPVC than control with periphytic diatoms belonging to Aulacoseira genus being dominant. This may be due to the temporal water body behavior or local retention of current by FPV system. This study may provide a measure of future installation of a FPV system.

• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.378-389
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• 2006

Seasonal changes of biomass and cell size of bacteria and protozoa, and factors affecting their distribution in Lake Paldang and Kyungan Stream were analyzed from April to December, 2005. Bacterial abundance at Paldang Dam and Kyungan Stream was similar, but it did not much increase during hot summer period. Protozoan carbon biomass was much greater at Kyungan Stream compared to Paldang Dam. HNAN generally accounted for the majority of total protozoan biomass, but ciliates made up the highest proportion in April and November at Paldang Dam and June at both sites. PNAN showed low biomass at both sites, but it was high during spring and fall season. Small-sized HNAN ($3{\sim}7\;{\mu}m$) numerically predominated the protozoan community at both sites. Average cell size of HNAN was bigger at Kyungan Stream where nutrients concentration was much higher than Paldang Dam. Average cell size of ciliates varied seasonally; it was relatively small during the summer. HNAN biomass significantly correlated with Chl-a concentration and ciliates biomass at Paldang Dam, indicating that HNAN increase might link to the ciliates increase. At Kyungan Stream, HNAN biomass showed a significant relationship with PNAN biomass, and Chl-a concentration was closely related with both of HNAN and PNAN biomass. Ciliate biomass showed significant relationship with nutrient (TN, TP) and particulate matter (SS) only at Kyungan Stream. At both sites, protozoan biomass was significantly correlated with bacterial biomass, and ciliates were additionally related flagellates. High biomass of microbial components and the close relationships among them suggest that the energy transfer through the microbial loop may important in the plankton food web of Lake Paldang ecosystem.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.5
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• pp.1-15
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• 2020

This study was designed to come up with a way of managing a cultural landscape forest by conducting research on the vegetation structure and growth characteristics. This study's target site, which was 45,201㎡ in size, was Pinus densiflora forest for Sugumagi placed at the entrance of Unmun Temple, Sinwon-ri, Unmun-myeon, and Cheongdo-gun in the southernmost part of Gyeongsangbuk-do, Korea. Sugumagi means the water of the valley flows far away, and where no downstream is visible according to feng shui. The historical sources of the Sugumagi Pinus densiflora forest at the entrance of Unmun Temple isn't clear. It waw only found at that location. The Pinus densiflora forest at the entrance of Unmun Temple is located in the waterway in terms of Feng Shui. The present condition of growth was investigated through a grid surveys of 98 trees and Pinus densiflora growth. As a result of the analysis of growth status, Pinus densiflora, Larix leptolepis, Zelkova serrata, Celtis sinensis, and Rhus javanica were distributed in the conopy layer, and 28 species including Ailanthus altissima were grown in the understroy layer, and 92 species, including Ampelopsis brevipedunculata, in the shrub layer. The plant community structure was divided into low, medium and high-density Pinus densiflora forests in the study area, based on the number in the conopy layer and the grade of and the trees analyzed. As a result of the analysis, the Pinus densiflora dominated the low, medium and high-density Pinus densiflora forests, and there were no competitive species. The relative dominance of the low-density Pinus densiflora forests was 46.9% on average, medium-density was 62.6% and 50.2% was found in high-density. The mean species diversity of Shannon in the low-density study was 0.7055, medium-density study was 0.8966 and the average species diversity of Shannon in the high-density study was 0.8317. The analysis of the age and growth of 25 sample trees in the Sugumagi Pinus densiflora forest shows that the distribution of the chest diameter (DBH) of the sample Pinus densiflora is 38 to 77cm with the average chest diameter being 61.1cm. The age was 84-161 years and the average was 114 years. In the Pinus densiflora forest, most(670,659, or 98.3%) of the tree trunk wound was collected for rosins during the Japanese colonia Era, Of the total 670, 659 were Pinus densiflora, 98.3% of the total. 394 were surgically repaired in 2005. For the preservation of the Sugumagi Pinus densiflora forest, dead trees should be replaced with substitute trees appropriate to the middle and south topography. It is demanded that foreign species such as Larix leptolepis in the research area should be removed and Pinus densiflora that underwent surgical operations should be regularly sterilized. It is also emphasized that the management of insecticide is important.

• Journal of Wetlands Research
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• v.18 no.1
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• pp.32-38
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• 2016

The purpose of this study is to investigate the effects of the natural river conservation work and to find remedies for them, targeting Jangsu-cheon with high frequency of use by citizens among the rivers in Incheon Metroplitan City, Korea; for this, this study conducted investigations and analyses of Jangsu-cheon completed in December, 2008. As a result of investigating 3 spots for the water system of Jangsu-cheon over a total of 3 years (2009, 2010, 2014), it was found that benthic macro-invertebrates of a total of 3 phyla, 5 classes, 11 orders, 26 families, 56 species, and 980 specimens were distributed there. When they were analyzed by year, 18 families and 30 species in 2009, right after the natural river conservation work, and 22 families and 37 species in 2010, 2 years after the work, were found, with 7 species increasing in number; after that, as a result of the investigation in 2014, 22 families and 38 species were found, which tells the river has entered the stabilization stage since the recovery in 2010.Therefore, this study could identify: the water environment of the river was improved due to the natural river conservation work for Jangsu-cheon; in addition, Jangsu-cheon showed good ecological environment due to the continuous maintenance of the good wetlands in Incheon Grand Park in the upper area of the river; and the natural river conservation work of Jangsu-cheon created positive effects.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.6
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• pp.12-23
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• 2019

The purpose of this study was to develop and study an experiential natural education program that could emphasize the importance of the natural environment by providing natural experience opportunities using the natural resources of the urban forest parks using Youngheung Park in Suwon, Gyeonggi Province as a target site. The research target was limited to Suwon Yeongheung Park, which had the potential to become a place for education, where urban forest conservation and sustainable use already coexist. The natural education resources derived by surveying and analyzing the basic environment and the ecology of plants and animals in Suwon Yeongheung Park were organized to establish program goals, directions, and themes. Suwon Yeongheung Park is a water-rich forest that forms an ecological system of wetlands, including rice paddies, muknon wetlands, and dungbun, near a valley area. The U-shaped walkway was smoothly formed along the ridge and includes Doran-gil, which is among the Palochrome Road, designated by the city of Suwon. The soil is acidic, with a pH 4.40, due to urban pollution and acid rain, and is not good for plant growth. Most of the artificial forests, natural forests, and arable land were found using land use and extant life surveys. Old trees were distributed in artificial forests, the oak clusters in natural forests, and the fields and darrinones were distributed in the arable areas. As the forest vegetation declined, the cedar forest was underway, and the cedar trees and red bean pear trees were cultivated due to their adaptability to the urban environment. There are 13 large of 180 sacks, one being 109 centimeters in diameter, the largest silvery tree, and 105 oak trees, provide food and shelter for animals. Six species of waterfowl that used the 22 kinds of forest wetlands, while four species of amphibians and two species of reptiles reside in the wetlands. Natural Monument No. 327, Mauryuk, Class II Endangered Wildlife, was also observed in the wetlands. Eight other species of surface dragonflies and three species of butterflies were observed. By systemizing the resources, members, and characteristics of the forest ecosystems in Suwon Yeongheung Park based on five criteria, the program for a hands-on natural education was presented with the aim of understanding the urban forest ecosystem in Suwon Yeongheung Park, having an affinity with the city, and recognizing its relationship with the community and society. However, further research is needed as there are limitations of research on programs characterized by different ages and classes.

• The Korean Journal of Ecology
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• v.22 no.3
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• pp.145-153
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• 1999

Authors report the changes of the community structure and secondary succession after fire in Mt. Samma (333 m). Approximately six ha of the red pine (Pinus densiflora) forest and its floor vegetation were burned and cutted down. The vegetation and soil properties were investigated in the burned and unburned sites from April to October, 1998. The dominant species based on SDR₃ in the burned site were Lespedeza cyrtobotrya (96.87), Quercus serrata (77.90), Cyperus amuricus (46.22) and Miscanthus sinensis var. purpurascens (38.33), whereas the dominant species in the unburned site were Pinus densiflora (100.00) and Q. variabilis (66.10) at the tree layer, Q. serrata (100.00) and Zanthoxylum schinifolium (29.64) at the shrub layer., and Q. serrata (76.30) and M. sinensis var. purpurascens (72.84) at the herb layer. The biological spectra based on SDR₃ were Th-D₁-R/sub 5/-e for the burned and H (M)-D₁-R/sub 5/-e type for the unburned site, respectively. The index of similarity (CCs) between the burned and unburned sites was 0.41. The degree of succession (DS) were 609 for the burned and 1168 for the unburned site, respectively. The species diversity (H) and evenness indices (e) of the burned site were lower than those of the unburned site, but the dominance indices (C) was higher in the burned site. In the analysis of soil properties, pH, the content of NO₃/sup -/-N, available phosphrous, and exchangeable cations (K/sup +/, Ca/sup 2+/, Na/sup +/, Mg/sup 2+/) in the burned site were higher than those in the unburned site, whereas the contents of organic matter, total carbon, total nitrogen and NH₄/sup +/-N were lower in the burned site. The results show that dominant species in the burned site change from Miscanthus-Lespedeza→Lespedeza→Quercus and finally to Quercus forest, and the changes of soil properties also affect the early vegetational succession after fire.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.20 no.4
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• pp.192-198
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• 2015

Picophytoplankton, a group of tiny microorganisms of less than $3{\mu}m$, play an important role as a major primary producer in tropical open ocean as well as temperate coastal waters. Until now, more than 20 and 10 clades of Synechococcus and Prochlorococcus, respectively, have been identified in various marine environments, and its biogeographical distribution have been well studied as well as ecological niches of its major clades. To understand a distribution of diverse picocyanobacterial clades and environmental factors regulating their distribution, picocyanobacterial abundance and genetic diversity was investigated in adjacent waters of Dokdo showing diverse physical properties not only by seasonal variation but also by diverse physical processes. Synechococcus abundances were low in winter and then exponentially increased as water temperature increased up to $20^{\circ}C$. Above $20^{\circ}C$, the abundances tended to be saturated. On the contrary, Prochlorococcus was undetected or occupied a minor fraction of picocyanobacteria in most seasons. In summer, however, Prochlorococcus belonging to HLII ecotype occupied a significant fraction (up to 7%) of picocyanobacteria. In spring and early summer, the steep increase of Synechococcus abundances were resulted from growth of cold water-adapted Synechococcus belonging to clades I and IV. In summer, diverse Synechococcus clades including warm and pelagic water-favoring clade II tended to replace clades I and IV with maintaining high abundance. The water-column stability as well as temperature were found to be important factors regulating the Synechococcus abundances. Moreover, inflow and mixing of distinct water masses with different origins exerted significant influence on the composition of Synechococcus in the study area. Thus, physical processes as well as natural seasonal variation of environmental factors should be considered to better understand ecology of planktonic organisms around Dokdo.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.411-422
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• 2004

A limnological survey was conducted in a reservoir, Lake Hoengsung located in Kangwondo, Korea, from July 2000 to September 2001 on the monthly basis. Phosphorus loading from the watershed was estimated by measuring total phosphorus concentration in the main tributary. Secchi disc transparency, epilimnetic (0-5 m) turbidity, chlorophyll a (Chl-a), total phosphorus (TP), total nitrogen(TN) and silica concentration were in the range of 0.9-3.5 m, 0.1-8.5 NTU, 0.3-32.4 mgChl $m^{-3}$, 5-46 mgP $m^{-3}$, 0.83-3.55 mgN $L^{-1}$ and 0.5-9.6 mgSi $L^{-1}$, respectively. Green algae and cyanobacteria dominated phytoplankton community in warm seasons, from July through October, 2000. In July a green alga (Scenedesmus sp.) was dominant with a maximum cell density of 10,480 cells mL. Cyanobacteria (Microcystics sp.) dominated in August and September with cell density of 3,492 and 295 cells mL ,respectively. Species diversity of phytoplankton was highest (2.22) in July. The trophic state of the reservoir can be classified as eutrophic on the basis of TP, Chl-a, and Secchi disc transparency. Because TP concentration was high in flood period, most of phosphorus loading was concentrated in rainy season. TP loading was calculated by multiplying TP and flow rate. The dam managing company measured inflow rate of the reservoir daily, while TP was measured by weekly surveys. TP of unmeasured days was estimated from the empirical relationship of TP and the flow rate of the main tributary; $TP=5.59Q^{0.45}\;(R^2=0.47)$. Annual TP loading was calculated to be 4.45 tP $yr^{-1}$, and the areal P loading was 0.77 gP $m^{-2}\;yr^{-1}$ which is similar to the critical P loading for eutrophication by Vollenweider's phosphorus model, 0.72 gP $m^{-2}\;yr^{-1}$.

• Korean Journal of Ecology and Environment
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• v.47 no.4
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• pp.319-327
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• 2014

Understanding and quantifying of carbon storage in ecosystem is very important factor for predicting change of global carbon cycle under the global climate change. We estimated total ecosystem carbon in Gyeryongsan National Park with naturally well preserved ecosystem in Korea. Vegetation of Gyeryongsan National Park was classified with mainly four communities with Quercus mongolica (1,743.5 ha, 38.0%), Quercus variabilis (1,174.0 ha, 25.6%), Quercus serrata (971.9 ha, 21.2%), Pinus densiflora (695.2 ha, 15.2%). Biomass and soil carbons were calculated from biomass allometric equations based on the DBH and carbon contents of soil and litter collected in quadrat in each community. The tree biomass carbon was in Quercus variabilis ($130.1tCha^{-1}$), Pinus densiflora ($111.1tCha^{-1}$), Quercus mongolica ($76.2tCha^{-1}$), Quercus serrata ($39.0tCha^{-1}$). Soil carbon storage was in Quercus mongolica ($159.7tCha^{-1}$), Quercus serrata ($121.0tCha^{-1}$), Pinus densiflora ($110.5tCha^{-1}$), Quercus variabilis ($90.8tCha^{-1}$). Ecosystem carbon storage was Pinus densiflora ($239.9tCha^{-1}$), Quercus mongolica ($235.9tCha^{-1}$), Quercus variabilis ($226.0tCha^{-1}$), Quercus serrata ($165.9tCha^{-1}$), total amount was $867.7tCha^{-1}$. The area of each vegetation carbon storage was Quercus mongolica ($411,200tCha^{-1}$), Quercus variabilis ($265,300tCha^{-1}$), Pinus densiflora ($166,800tCha^{-1}$), Quercus serrata ($161,200tCha^{-1}$) and the total ecosystem carbon amount estimated $1,045,400tCha^{-1}$ at Gyeryongsan National Park. Theses results indicate that different in naturally well preserved ecosystem.