• Korean Journal of Ecology and Environment
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• v.50 no.2
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• pp.216-237
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• 2017

Thermal effluent of the hot spring has long been a field of interest in the relationship between temperature gradient and freshwater algae in geology, limnology and aquatic ecology throughout the world. On the other hand, many artificial hot springs have been developed in Korea, but the research on them has not been still active. This study was performed every month from December 2015 to September 2016, to elucidate the spatiotemporal effects of thermal wastewater effluent (TWE) on the ecosystem of benthic algal assemblage in four stations(BSU (upstream), HSW (hot spring wastewater outlet), BSD1~2 (downstream)) of the upstream reach of the Buso Stream, a tributary located in the Hantan River basin. During the survey, the influencing distance of temperature on TWE was <1.0 km, and it was the main source of N P nutrients at the same time. The effects of TWE were dominant at low temperature and dry season (December~March), but it was weak at high temperature and wet season (July~September), reflecting some seasonal characteristics. Under these circumstances, the attached algal communities were identified to 59 genera and 143 species. Of these, the major phylum included 21 genera 83 species of diatoms(58.0%), 9 genera 21 species of blue-green algae (14.7%) and 25 genera 32 species of green algae (22.4%), respectively. The spatiotemporal distribution of them was closely related to water temperature ($5^{\circ}C$ and $15^{\circ}C$) and current ($0.2m\;s^{-1}$ and $0.8m\;s^{-1}$). In the basic environment maintaining a high water temperature throughout the year round, the flora favoring high affinity to $PO_4$ in the water body or preferring stream habitat of abundant $NO_3-PO_4$ was dominant. As a result, when compared with the outcomes of previous algal ecology studies conducted in Korea, the Buso Stream was evaluated as a serious polluted state due to persistent excess nutrient supply and high thermal pollution throughout the year round by TWE. It can be regarded as a dynamic ecosystem in which homogeneity (Summer~Autumn) and heterogeneity (Winter~Spring) are repeated between upstream and downstream.

• Journal of Environmental Impact Assessment
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• v.27 no.6
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• pp.674-684
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• 2018

The purpose of this study is to construct ecological pond using LID technique in order to create naturally comfortable community space in urban idle space. The specification of the ecological pond is $110m^2$ of surface area, $0.45{\pm}0.02m$ of average depth, and bed material is composed of gravel (diameter ${\leq}60mm$), sand (diameter ${\leq}2mm$) and bentonite. Rainfall and water depth monitoring were conducted to determine the annual characteristics of inflow of the water for the ecological pond, result of total rainfall was 1,287 mm and showed a seasonal imbalance that accounted for 71.3% (918 mm) during July to August, but the annual mean water depth was kept constant at $0.45{\pm}0.02m$ due to the secondary water source. Annual trends of basic water quality showed a significant changes according to the season, such as water temperature ($5.2{\sim}28.8^{\circ}C$), DO (5.0 ~ 13.8 mg/L), EC ($113{\sim}265{\mu}S/cm$). BOD, COD, TN, and TP in physicochemical water quality tended to increase after October, but the ion parameters such as $NH_3$ and $PO_4{^{3-}}$ were generally low. Phytoplankton indicators Chl-a and BGA (blue green algae) showed a sharp increase from July to August, and green algae (Selenastrum bibraianum, Pediastrum boryanum etc.) and filamentous blue green algae (Phormidium sp.) emerged as a dominant species. The ion parameters ($F^-$, $Na^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$) were strongly correlated with the $Cl^-$ as a conservative substance (R=0.70~0.97, p<0.05). Water quality was influenced by the ambient environment such as seasonal changes or rainfall, and it was closely related to fluctuation of the inflow of the water. In the future, it is necessary to consider ecological connections by referring to the characteristics surveyed in this study in order to effectively manage the water quality and biodiversity of the ecological pond in idle space.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.2
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• pp.64-73
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• 2015

The distributions of Pb and Cd concentrations in the surface seawater of the East Sea were investigated during the R/V Lavrentyev cruise (July 2009) in which four transects from Russia shore to South were conducted to collect 26 surface water samples. The total dissolved concentrations of Pb and Cd were measured using ICP-MS (Perkin Elmer, DRC-e). In the coastal area, their concentrations of Russia shore (Pb, 0.08; Cd, 0.10 nM) were comparable for Cd but on the other hand, 6 times lower for Pb than Korea shore (Pb, 0.49; Cd, 0.11 nM). In the subregion, their concentrations of Warm region (Pb, 0.22; Cd, 0.01 nM) were about 1.7 times higher for Pb but 0.4 lower for Cd than Cold region (Pb, 0.13; Cd, 0.14 nM). The distributions of Pb and Cd concentrations were divided by lowest level at $10^{\circ}C$ of water temperature. Below $10^{\circ}C$, Pb and Cd concentrations increased when surface water temperatures decreased. Above $10^{\circ}C$, their concentrations increased with temperature, which showed highest concentrations in the Ulleung basin, directly influenced by flux from East Korean Warm Current and neighboring countrys (Korea and Japan). Specially, in the case of Pb, the concentrations decrease remarkablely with temperatures decrease from D10 directly influenced by flux from East Korean Warm Current, which shows highest Pb level. By comparing with other sea areas (Western Mediterranean, East Pacific), Pb concentrations in the East Sea were a little higher. The influence of East Korean Warm Current and neighboring countrys (Korea and Japan) may be relatively important. Therefore, the distribution of Cd may primarily be influenced by mixing of different water masses while the distribution of Pb may mainly be influenced by flux from East Korean Warm Current and atmospheric inputs. River inputs and interaction with particulate materials may also some roles for the distribution of these elements.

• Korean Journal of Environmental Biology
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• v.24 no.3
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• pp.248-257
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• 2006

Total naturalized plant species in the streams of Jeonju were listed as 109 taxa; 24 families, 75 genera, 106 species, 3 varieties. Dividing by stream, Jeonju stream has 75 taxa; 20 families, 55 genera, 73 species, 2 varieties. Samcheon stream has 86 taxa; 19 families, 64 genera, 84 species, 2 varieties. Soyang stream has 80 taxa; 21 families, 60 genera, 77 species, 3 varieties. Urbanization Index (UI) of total streams (109 taxa) was 40.2%. UI was 27.7% in Jeonju stream (75 taxa), 31.7% in Samcheon stream (86 taxa), 29.5% in Soyang stream (80 taxa). Dividing by degree of naturalization classification, 25 taxa (9.2%) were found in class 5, 17 taxa (6.2%) in class 4, 32 taxa (11.8%) in class 3, 27 taxa (9.9%) in class 2 and 8 taxa (2.9%) in class 1. Dividing by introduction period, 48 taxa (44%) aye in period I, 19 taxa (17%) in period II, 42 taxa (39%) in period III. Dividing by growth type, 48 taxa (44%) are annuals, 25 taxa (23%) are biennials, 33 taxa (30%) are perennials. Dividing by the place of origin, 39 taxa (35%) are from Euyope, 33 taxa (30%) from North America, 11 taxa (10%) from Tropic America, 9 taxa (8%) from Europe Asia,5 taxa (5%) from South America, 5 taxa (5%) from China.

• Journal of Animal Environmental Science
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• v.12 no.1
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• pp.35-40
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• 2006

This experiment was conducted to investigate the effect of application level of swine slurry on the growth characteristics and yield of sorghum$\times$sudangrass hybrid and $NO_3-N$ content in infiltration at experimental field of Grassland and Forage Crops Division, National Livestock Research Institute, RDA from 2000 to 2002. Treatments were consisted of non fertilizer(NF), chemical fertilizer(CF), 100% swine slurry(SS 100), 150% swine slurry(SS 150), 200% swine slurry(SS 200) and 100% swine slurry + CF 50%(SS100 + CF 50) with randomized complete block design and three replications. Growth of sorghum$\times$sudangrass hybrid was not nearly different among the treatments, but early growth of swine slurry treatments was better than that of CF, and regrowth after 1st cutting was shown better in CF and SS 100+CF 50 with adding application of chemical fertilizer. The sugar content(brix %) was tends to be increased with swine slurry application. Dry matter(DM) yields of SS 100 and SS 150 were lower 15 and 6% than that of CF, respectively, and SS 200 was similer to CF, but there was not found significant difference among all treatments. The content of crude protein(CP), acid detergent fiber(ADF), and neutral detergent fiber(NDF) did not show the difference. The content of $NO_3-N$ in infiltration water was not more than CF by the 55 150 application, but more than by SS 200 and 55 100+CF 50 treatment.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.311-325
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• 2007

The concept of metal bioavailability, rather than total metal in soils, is increasingly becoming important for a thorough understanding of risk assessment and remediation. This is because bioavailable metals generally represented by the labile or soluble metal components existing as either free ions or soluble complexed ions are likely to be accessible to receptor organismsrather than heavy metals tightly bound on soil surface. Consequently, many researchers have investigated the bioavailability of metals in both soil and solution phases together with the key soil properties influencing bioavailability. In order to study bioavailability changes various techniques have been developed including chemical based extraction (weak salt solution extraction, chelate extraction, etc.) and speciation of metals using devices such as ion selective electrode (ISE) and diffusive gradient in the thin film (DGT). Changes in soil metal bioavailability typically occur through adsorption/desorption reactions of metal ions exchanged between soil solution and soil binding sites in response to changes in environment factors such as soil pH, organic matter (OM), dissolved organic carbon (DOC), low-molecular weight organic acids (LMWOAs), and index cations. Increasesin soil pH result in decreases in metal bioavailability through adsorption of metal ions on deprotonated binding sites. Organic matter may also decrease metal bioavailability by providing more negatively charged binding sites, and metal bioavailability can also be decreases as concentrations of DOC and LMWOAs increase as these both form strong chelate complexeswith metal ions in soil solution. The interaction of metal ions with these soil properties also varies depending on the soil and metal type.

• Korean Journal of Ecology and Environment
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• v.37 no.3 s.108
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• pp.319-331
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• 2004

This study was conducted to evaluate the ecological impact of freshwater bivalve (Corbiculidae) on plankton communities in experimental enclosure systems (2 m ${\times}$ 2 m ${\times}$ 2 m). During the acclamation period of one month, cyanobacteria, including Microcystis viridis and Microcystis aeruginosa, dominated in both control and treatment enclosures with no noticeable density difference. After the addition of 100 mussels, dominant species of phytoplankton shifted from Microcystis to Scenedesmus in concert with slight decrease in the cell density and the increase of N/P ratio. However, cell density in the control quickly increased, accompanied with changes of dominant species to Oscillatoria spp. With the introduction of additional 500 musseles in the treatment enclosure, dominant phytoplankton species in both enclosures were replaced with Selenastrum spp. and Cryptomonas sp. In the initial stage, the total zooplankton abundance in the control was higher than that of treatment, but it was reversed after the addition 100 mussels. After mussel density increased up to 600 indivisuals, zooplankton density in the treatment decreased with dominance of small taxa, such as rotifers and nauplius. However, abundance and carbon biomass of large zooplankton, such as Bosmina longirostris and Diacyclops thomasi were maintained in a high level compared with those of control. During the study period, Chl. a concentration in mussel treatment and control increased with DIP and $NH_3-N$, respectively. Due to the increase of $NH_3-N$, especially after the introduction of additional 500 mussels, nitrogen limitation did not occur in the treatment enclosure in contrast with strong nutrient limitation occurred in the control. These results indicate that filter-feeding Corbicula could exert important impact on nutrient recycling and plankton community structure in a freshwater ecosystem, through direct feeding and competition for the same food resource as zooplankton on one hand, and through alteration of nutrient availability on the other.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.97-103
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• 2004

This study was performed to assess the influences of liquid pig manure (LPM) on the rice growth and nutrient behavior in soil under two different drainage comditions. Soils of paddy field were Jeonbuk and Gangseo series, and drainage conditions of the soils were imperfectly drained and moderate well drained, respectively, Application of LPM was based on nitrogen, and the treatments included 110 (LPM-N100%), 165 (LPM-N150%) and $220(LPM-N200%)kg\;N\;ha^{-1}$. In the LPM-N150% treatment, rice growth and yield were similar to the control treatment of conventional chemical fertilizer application. Rice yield of moderately well drainedfield were 3-11% higher than that of imperfectly drained field. Loss of nitrogen through $NH_3$ gas after application of LPM was higher in no plowing than in rotary plowing field. Losses of $NO_3-N$, $NH_4-N$, $SO_4$, Ca and K through runoff water were increased as the amount of LPM application increased. Losses of $NO_3-N$ and K through infiltration were higher in LPM-150% and LPM-N200% treatments compared to the chemical fertilizer treatment. Contents of $NO_3-N$ in infiltration water measured from trasplanting to tillering stage was higher at the moderately well drained condition than imperfectly drained condition. Contents of $P_2O_5$ and K in soil were accumulated by application of LPM compared to the chemical fertilizer plot.

• Journal of the Korean association of regional geographers
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• v.13 no.4
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• pp.409-421
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• 2007

The purpose of this paper is to consider the formation processes and depositional conditions of bars formed at the upper-stream part of Sayeon Dam since Sayeon Dam construction in 1964. Results of analyzing the shape characteristics of bars and their sediment grain size distribution are as follow: Firstly, bars are able to categorized as subaqueous bars (A, B), mid-channel bars(C, D), and tributary side-bars(E). Secondly, the outline of bars has longish along the flow path, and their height lowers more and more going towards downstream. Also the height of bar surface tend to heighten from flow path to mountain slope. However, the near part of A is comparatively higher than its distant part, A is defined as a subaqueous natural levee and back swamp. Thirdly, the average particle size of A and B become smaller toward mountain slope. In transportation style, ratio of suspended load become higher toward mountain slope. Fourthly, sorting is worse to very worse according with lake's random changable water level. Fifthly, bar A and B were formed by vertical sedimentation of sediments according as sediments transported along flow path in the subaqueous conditions were spreaded out of flow path. C and D were formed by bed load as flood level lowered. And E was formed by vertical sedimentation while stream flow stopped in tributary's mouth areas with the water level heightening.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.55-55
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• 2011

연안 및 해안공학의 발달과 더불어 부유식방파제의 기능적 효율성이 중요시 되고 있다. 흔히 사용되어오던 착저식방파제는 설치에 많은 시간과 경비가 소요되고 환경 및 생태계에 많은 변화를 줄 수 있으며, 설치 예정지의 수리학적 특성 등의 여건에 많은 제약을 받는 단점이 있다. 부유식방파제는 일본 등의 선진국을 중심으로 활용이 잦아지고 있는 방파제로서 수면 위에 설치되기 때문에 수중 생태계에 미치는 영향이 적은 친환경방파제이다. 또한 기존에 시공된 중력식방파제와는 달리 수심에 제한을 덜 받고, 공사기간이 짧기 때문에 경제적이다. 실제 시공사례로는 2007년 마산 원전항에 완공된 부유식방파제가 대표적이며, 지금까지도 부유식방파제에 대한 여러 연구자들의 관심이 증가하고 있는 추세이다. 방파제뿐만 아니라 우리나라처럼 국토의 면적이 작은 지역에서 증가하는 해상물동량을 소화하기 위해서 부유식방파제 등을 이용한 항만의 시공이 필요한 실정이다. 이러한 부유식방파제의 분석적인 측면에 있어서 수치해석은 파랑과 구조물의 상호작용을 해석하는 데 한계가 있으며, 부유식방파제 단면형상을 정확하게 재현할 수 없으므로, 수리모형실험을 통한 부유식방파제의 연구가 필요할 것으로 판단된다. 최근 기술의 발달로 인한 유동장 해명이 가능해 졌으며, PIV(Particle image velocimetry) 및 LDV시스템은 다양한 분야에서 응용되고 있다. 특히, LDV시스템은 측정하려는 한 지점에 대하여 레이저 빔을 단면(Cross-section)으로 만들고 입자의 산란광을 후방산란(Back scatter)으로 받아서 도플러 효과를 이용, 속도에 대한 주파수를 획득하며, 유속을 측정하는 장비로 매우 높은 정확도와 비접촉식 이라는 장점을 가지고 있다. 또한, PIV 시스템에 비하여 측정시간이 오래 걸리는 반면 데이터를 가공하지 않고 활용할 만큼 높은 정확성을 가지고 있다. 본 연구에서는 수리모형실험을 통하여 단독형, 2열형 및 3열형 부유식방파제의 형상, 흘수 및 거리를 변화시키며 유동장을 수집하였으며, 방파성능에 따른 와의 생성 및 소멸시점에서의 파랑변형과의 관계를 분석하였다. 방파제의 형상과 흘수를 달리하여 수리모형실험을 수행하였으며, 와류의 상관관계를 분석하였다. 또한, 연직 2차원 Navier-Stokes 방정식 모형을 이용하여 수치모형실험을 수행하였으며, 수치모형실험 결과와 수리모형실험 결과를 비교 분석하였다. 후방방파제에서 발생되는 파랑은 입사파의 주기가 길어질수록 상대적으로 커지는 현상을 보였으며, 흘수심이 깊어질수록 전방방파제 입사 면에서 자유 수면이 높게 관측되는 결과를 보였다. 또한, 비교적 장주기파랑에 해당하는 입사파랑의 경우 전달파고비 산정에 있어서 설계기준인 0.5를 대다수 초과하는 반면, 3열형 구조에서는 대부분이 0.5이하로 상당히 높은 방파성능 결과를 나타내었다.