• Title/Summary/Keyword: Nitrate

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Effect of Freshwater Discharge on the Seawater Quality (Nutrients, Organic Materials and Trace Metals) in Cheonsu Bay (여름철 천수만 해수에서 담수 대량 방류에 따른 영양염, 유기물 및 미량금속의 변화)

  • LEE, JI-YOON;CHOI, MAN-SIK;SONG, YUNHO
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.24 no.4
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    • pp.519-534
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    • 2019
  • When the fresh water from the artificial lakes (Ganwolho and Bunamho) were discharged to Cheonsu Bay in summer to prevent the flood over the reclaimed farmland near the lakes, the impact on water qualities (nutrients, organic matters, trace metals) within the bay was investigated through four surveys (June, July, August and October, 2011). Dissolved inorganic nitrogen (DIN) increased about as much as 3-4 times over the whole water column when the freshwater was discharged. And the main species composition of DIN changed from ammonia to nitrate. Dissolved inorganic phosphorus (DIP) decreased as much as 2 times in surface waters, but increased as much as 1.5 times in deep waters, and also silicate concentrations increased as much as 3-4 times in deep waters of the inner bay. The N/P ratios in Chunsu bay seawaters were much higher (2 to 7 times) than the Redfield ratio when the freshwaters were discharged, which indicated the phosphorus limiting in the phytoplankton growth. Dissolved organic carbon (DOC) and nitrogen (DON) increased as much as about 2 times. In addition, particulate organic matters (POC, PON, POP, Bio-Si) increased as much as above 2 times in the surface waters of the inner bay. Trace metals (Fe, Mn, Co, Ni, Cu) increased in the surface waters of the inner bay, but dissolved Cd concentrations decreased as much as 2 times. Therefore, when the contaminated fresh waters from the artificial lakes were discharged into the bay, nutrients, organic matters and trace metals generally increased compared to normal period. Since the phytoplankton bloom occurred in the surface waters of the inner bay, dissolved oxygens at the surface waters were oversaturated and hence hypoxic in the deep waters. Highly enriched nutrients concentrations were found in deep waters of the inner bay, which was accompanied with the hypoxic condition. Finally, the water quality in the inner bay of the Chunsu bay was deteriorated from less than grade 3 in normal periods to grade 5 when the freshwaters from the artificial lakes were discharged in summer.

Rhizosphere Enhances Removal of Organic Matter and Nitrogen from River Water in Floodplain Filtration (홍수터 여과를 이용한 하천수의 질소와 유기물 제거에 미치는 근권의 효과)

  • Jeong, Byeong-Ryong;Chung, Jong-Bae;Kim, Seung-Hyun;Lee, Young-Deuk;Cho, Hyun-Jong;Baek, Nam-Joo
    • Korean Journal of Soil Science and Fertilizer
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    • v.36 no.1
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    • pp.8-15
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    • 2003
  • If contaminated river water is sprayed over a floodplain, the microbial processes can simultaneously remove organic matter and nitrogen during the infiltration through the sediment profile. The effect of rhizosphere on the removal of organic matter and nitrogen from contaminated river water was investigated using floodplain lysimeters. River water was sprayed at a rate of $68.0L\;m^{-2}\;d^{-1}$ on the top of the lysimeters with or without weed vegetation on the surface, Concentrations of $NO_3$, $NH_4$ and dissolved oxygen (DO), and chemical oxygen demand (COD) and Eh in water were measured as functions of depth for 4 weeks after the system reached a steady state water flow and biological reactions. A significant reductive-condition for denitrification developed in the 30-cm surface profile of lysimeters with weeds. At a depth of 30 cm, COD and $NO_3$-N concentration decreased to 5.2 and $0.9mg\;L^{-1}$ from the respective influent concentrations of 18.2 and $9.8mg\;L^{-1}$. The removal of $NO_3$ in lysimeters with weeds was significantly higher than in those without weeds. Vegetation on the top was assumed to remove $NO_3$ directly by absorption and to create more favorable conditions for denitrification by supply of organic matter and rapid $O_2$ consumption, In the lysimeters without weeds, further removal of $NO_3$ was limited by the lack of an electron donor, i.e. organic matter. These results suggest that the filtration through native floodplains, which include rhizospheres of vegetation on the surface, can be effective for the treatment of contaminated river water.

Effects of Crimson Clover, Hairy Vetch, and Rye Residue Mulch on Weed Occurrence, Soybean Growth, and Yield in Soybean Fields (콩 재배 시 크림손클로버, 헤어리벳치, 호밀 예취물 피복이 잡초 발생과 콩 생육 및 수량에 미치는 영향)

  • Lee, Ji-Hyun;Lee, Byung-Mo;Shim, Sang-In;Lee, Youn;Jee, Hyeong-Jin
    • Korean Journal of Weed Science
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    • v.31 no.2
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    • pp.167-174
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    • 2011
  • Weed control using cover crops has advantages of agricultural and environmental aspects which prevent soil erosion, nitrogen supply, improving soil physical properties, reduction of nitrate leaching, organic supply and control of weed occurrence. In this study, we evaluated the inhibitory effects of cover crops on the weed occurrence, growth and yield of soybean in cover crop-soybean cropping system. The treatments were consisted of 4 different mulching system such as crimson clover (Trifolium incarnatum) residue, hairy vetch (Vicia villosa) residue, rye (Secale cereale) residue and Polyethylene plastic(P.E.) mulch with no mulch treatment (control). Three cover crops were grown throughout the winter and were cut in next spring. And then 13 days old soybean seedlings were transplanted in each treatment field on $4^{th}$ June. Crimson clover, hairy vetch and rye mulch treatments reduced weeds density compared to control (73.0%, 98.0% and 85.3% respectively), on $26^{th}$ May. However, weed inhibition rate of crimson clover mulch treatment was sharply decreased to 4.17% on $6^{th}$ August, while hairy vetch and rye mulch treatments were continued high weed inhibition rate with 87.6% and 72.0% respectively. There was no inhibition effect of perennial, winter annual and broadleaf weeds inhibition in crimson clover mulch treatment. Height of soybean in crimson clover, hairy vetch and P.E. mulch treatment was 6.9%, 20.2% and 22.0% higher than that of control. But height of soybean in rye mulch treatment was lower than control on $13^{th}$ July. At harvesting, yields of soybean were in order of hairy vetch mulch treatment${\fallingdotseq}$ P.E. mulch treatment > crimson clover mulch treatment ${\fallingdotseq}$ rye mulch treatment > control.

Studies on the Ecology of Occurrence and Identification of Typhula Snow Mold of Graminous Plants -II. Several Factors Affecting Growth of Typhula incarnata- (화본과식물에 발생하는 설부소입균핵병균(雪腐小粒菌核病菌)의 동정 및 발생상태에 관한 연구 -II. Typhula incarnata의 생육에 미치는 몇 가지 요인-)

  • Kim, Jin-Won;Lee, Du-Hyung;Shim, Gyu-Yul
    • The Korean Journal of Mycology
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    • v.20 no.1
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    • pp.37-43
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    • 1992
  • Typhula incarnata grew over a temperature range of -5 to $20^{\circ}C$ with maximum growth at 10 to $15^{\circ}C$. Sclerotial production for T. incarnata was greatest at the higher temperature. Maximum mycelial growth of this pathogen occurred from pH 5.4 to 6.2. When carbon sources were added to a basal salt medium (Czapek's dox agar) at 5 g carbon sources/l, inulin, soluble starch, galactose, glucose, mannose, manitol, sucrose, maltose, cellobirose, trehalose, raffinose, and dextrin supported growth better than other carbon sources did. Of the twenty-three nitrogen sources tested, glycine, serine, ammonium sulfate, asparagine, asparatic acid, and ${\beta}-alanine$ were the most favorable for mycelial growth of T. incarnata. Cystine and cysteine were poor nitrogen sources. Ammonium salt of nitrogen sources supported growth better than nitrate salt of nitrogen sources. Potato dextrose agar, oat meal agar, and V-8 juice agar were the most favorable for mycelial growth and sclerotial formation. Appropriate addition of pepton to PDA decreased mycelial dry weight, but sucrose supported good growth of T. incarnata. Percent viable sclerotia of T. incarnate buried in bentgrass soil decreased from 2 months after treatment remarkably. Trichoderma riride and bacteria were isolated from non-germinated sclerotia. Live orchard grass leaf pieces within the soil were colonized by T. incarnata better than sterile and unsterile dead leaf pieces at $0^{\circ}C$. Saprophytic ability of T. incarnate on sterile leaf sheath occurred better at $0^{\circ}C$ than at $10^{\circ}C$. Saprophytic microflora consisting of Cladosporium sp., Fusarium sp., Mucor sp., Pythium sp., and unidentified fungi were the competitors for the sterilized and unsterilized substrate, but their colonization was not find on live leaf sheath buried in the soil at $0^{\circ}C$. In the effect of fungicides to Typhula snow mold disease of creeping bentgrass, mixture of polyoxin and thiram was the most effective, followed by iprodione, mixture of iprodione and oxine copper, thiophanate-methyl, myclobutanil, and tolclofos-methyl.

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Environmental Studies in the Lower Part of the Han River VIII. Physicochemical Factors Contributing to Variation of Phytoplankton Communities (한강 하류의 환경학적 연구 VIII. 식물플랑크톤 군집의 변화에 미치는 물리 화학적 요인)

  • Kwon, Oh-Youn;Jung, Seung-Won;Lee, Jin-Hwan
    • Korean Journal of Ecology and Environment
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    • v.39 no.3 s.117
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    • pp.340-351
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    • 2006
  • To reveal physicochemical factors contributing to variation of phytoplankton communities, the study was carried out biweekly at 6 stations from Feb. 2004 to Feb. 2005 in the lower part of the Han River, Korea. As results, water temperature was changed from $0.3^{\circ}C$ to $26.6^{\circ}C$, pH: 6.6${\sim}$9.1, DO: 1.89${\sim}$22.23 mg $L^{-1}$, BOD: 0.38${\sim}$9.20 mg $L^{-1}$, COD: 1.4${\sim}$15.2 mg $L^{-1}$, Conductivity: $62.5{\sim}500.0\;{\mu}s\;cm^{-1}$, SS: 3.00${\sim}$159.3 mg $L^{-1}$, and Chl a $1.7{\sim}71.3\;{\mu}g\;L^{-1}$. Phytoplankton standing crops ranged from min. $3.6{\times}10^2\;cells\;mL^{-1}$ (July 2004, St. 3) to max. $2.3{\times}10^4\;cells\;mL^{-1}$ (Feb. 2005, St. 6), and mean of those varied from $5.9{\times}10^3\;cells\;mL^{-1}$in spring, $2.1{\times}10^3\;cells\;mL^{-1}$ in summer, $4.1{\times}10^3\;cells\;mL^{-1}$ in autumn and $8.5{\times}10^3\;cells\;mL^{-1}$ in winter, respectively. In order to investigate factors influencing the total phytoplankton standing crops a multiple regression analysis was adopted for the correlation between standing crops and environmental factors. The coefficient of determination ($R^2$) value of the regression was 0.465, it showed that environmental factors which predominantly influenced phytoplankton standing crops were water temperature, COD, $NO_2-N$, $PO_4-N$, Discharge and pH. six stations could be divided into 3 groups based on similarity index in terms of environmental factors. In ANOVA analysis for physicochemical and biological factors, water temperature, chlorophyll a, silicate, phytoplankton standing crops were the same group differed little from stations. However, Station 1and 2 were grouped followed in dissolved oxygen, conductivity, COD, nitrite, nitrate, ammonia and phosphate, and Station 3, 4 and 5 were followed in dissolved oxygen, conductivity, pH and phosphate.

Effects of Farming on Soil Contamination and Water Quality in Keum River Districts (금강유역 농업지대의 토양 및 수질오염)

  • Han, Kang-Wan;Cho, Jae-Young;Kim, Seong-Jo
    • Korean Journal of Environmental Agriculture
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    • v.16 no.1
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    • pp.19-24
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    • 1997
  • This studies was carried out to investigate the soil contamination and water quality affected by agricultural activities in the Keum river Districts. Soil pH of the Keum river districts were $5.56{\sim}7.09$ in Keum river headwater and Namdae-cheon but that of Keumgang-lake were $5.07{\sim}7.21$ because of the cattle shed and industrial complex around. Total nitrogen contents of soils were found difference as period of fertilizer application. Total phosphorous content of soils no difference were found between the headwater and Keumgang-lake. Heavy metal contents of soils were natural background level. Water pH of the Keum river districts ranged from 6.59 to 7.80 and COD was maintain below 1.0 mg/L. Total nitrogen content affected by a livestock wastes and sewage water were the higher than that of others and total phosphorous content showed below 0.5 mg/L. Nitrate nitrogen and ortho-phosphate contents were very high according to the influence a livestock waste and sewage water in headwater region of the Keum river partly. Chlorine and sulfate contents were high according to the influence of sea water invasion. Heavy metal contents of waters were natural background level.

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On the Spatio-temporal Distributions of Nutrients and Chlorophyll a Concentration, and the Environmental Factors on the Variation of Phytoplankton Biomass in the Shiahae, Southwestern Part of Korean Peninsula (시아해의 수질환경과 식물플랑크톤 생물량의 시ㆍ공간적 분포특성과 기초생물량변동에 영향을 미치는 환경특성)

  • 윤양호
    • Korean Journal of Environmental Biology
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    • v.18 no.1
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    • pp.77-93
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    • 2000
  • Field survey on the spatio-temporal distribution of water quality and chlorophyll a concentration, and the environmental factors on the variation of phytoplankton biomass were carried out at the 23 stations for four seasons in the Shiahae, southwestern coast of Korean Peninsula from February to October in 1995. I made an analysis on biological factor as chlorophyll a concentration as well as environmental factors such as water temperature, salinity and nutrients; ammonia, nitrite, nitrate, dissolved inorganic nitrogen, phosphate, N/P ratio, silicate and Si/P ratio. The waters in the Shiahae were not stratified due to the tidal mixing and high velocity of tidal current. And the high productivity in photic layer were supported by high nutrients concentration from freshwater on lands and bottom waters The low depth of transparency in the Shiahae had a bad influence upon primary production and marine biology. In Shiahae had a sufficient nutrients for primary production during a year. Especially dissolved inorganic nitrogen and silicate were high, the other side, phosphate was low. The source of nutrients in summer and silicate supply depend on input of freshwater from lands, the other side, dissolved inorganic nitrogen and phosphate were depend on rather supplied from bottom layer by the mixing and input of seawater from outside than input of freshwater from lands. Phosphate seemed to become a limiting nutrient for the primary production at all area of Shiahae in winter and at the northern parts in other seasons. However, dissolved inorganic nitrogen seemed to do it at the southern parts in other seasons except winter. Silicate didn't become a limiting nutrient for diatoms in Shiahae. Phytoplankton biomass as measured by chlorophyll a concentration was very high all the year round, it was controlled by the combination of the several environmental factors, especially of nitrogen, phosphorus and the physical factors such as light intensity. [Spatio-temporal distribution, Seasonal fluctuation, Nnutrients, Chlorophyll a, Environmental factors, Nutrient source, Limiting Nutrient, Light, Shiahae] .

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Comparisons of Growth and Fruit Quality of Citrullus lanatus cv. Mudeungsan and Citrullus vulgaris cv. Dalgona Grown in Fertigation and Soilless Culture (무등산수박과 달고나수박의 관비재배와 양액재배에 있어서 생육 및 과실품질의 비교)

  • 이범선;정순주;박순기
    • Journal of Bio-Environment Control
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    • v.8 no.1
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    • pp.19-29
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    • 1999
  • This experiment was conducted to compare with the growth and fruit quality of Citrullus lanatus cv. Mudeungsan and Citrullus vulgaris cv. Dalgona grown in fertigation and soilless culture. Seeds were sown on April 16 and transplanted on April 24, 1998. Cultural systems used in fertigation and soilless culture beds using mixed substrate, coir dust (50%) and perlite (50%). In the plot of fertigation system, the number of leaves of cv. Dalgona were increased more than that of cv Mudeungsan, but leaf area shown inversed trend. Plant growth shown greater in soilless culture than those of fertigation culture. In regardless of cultural systems, soluble solid content in fruit was higher in the cv. Dalgona than that of cv. Mudeungsan, but fruit fresh weight was greater in cv. Mudeungsan compare to the cv Dalgona. Nitrate content in petiole sap of watermelon in regardless of cultivars and cultural systems was 11.4∼13.4mg/gFW on 15 days after transplanting, and then increased to 17.1∼20.6mg/gFW on the fruit growth stage. Phosphorous content was 3.7∼5.7mg/gFW in the early growth stage while decreased to 0.6∼1.1mg/gFW from maturing stage to harvesting stage. Potassium content was increased to 5.8∼6.6mg/gFW in the early growth stage while decreased to 4.0∼4.8mg/gFW from pollination stage to harvesting stage. Calcium content in spa petiole of watermelon was higher in soilless culture as 3.4∼4.1mg/gFW than 2.5∼3.5mg/gFW of fertigation culture, but calcium content in fertigation culture during maturing stage was higher than that of soilless culture. The tendency of magnesium uptake was higher in fertigation culture than that of soilless culture, and was similarly absorbed in the range of 0.9∼1.3mg/gFW in regardless of cultural method after pollination. It was demonstrated that cv. Mudeungsan can be adapted to soilless culture and improved the fruit quality. Consequently, hydroponic possibility for year round culture in the greenhouse was recognized.

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A Pilot Scale Biostimulation Study for In-situ Remediation of Organic Pollutants and PAHs contained in Coastal Sediment (연안 해역퇴적물에 함유된 유기오염물과 PAHs의 현장정화를 위한 파일럿 규모의 생물활성촉진연구)

  • Bae, Byung-Uk;Woo, Jung-Hui;Subha, Bakthavachallam;Song, Young-Chae
    • Journal of Navigation and Port Research
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    • v.40 no.6
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    • pp.441-450
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    • 2016
  • A pilot scale biostimulation experiment was performed under field conditions to degrade organic pollutants and PAHs (Polycyclic Aromatic Compounds) in contaminated coastal sediment. During the experiment, the seawater temperature around the sediment varied from $16.5^{\circ}C$ to $21^{\circ}C$, while the sediment pH was stable at 8.4-8.5. The experiment was conducted over a one year period with a control group and a sample group with a applied biostimulant composed of acetate, sulfate, and nitrate. Chemical oxygen demand decreased 39% in the control group and 79% in the sample group. Volatile solids were reduced from 15 to 7 g/kg in the control group and 2.5 g/kg in the sample group. Out of the 2-, 3- ,4- ,5-, and 6-rings of the 16 vital PAHs, the compound including naphthalene (2-ring), took 2 months to degrade completely, while the degradation efficiency was 55.6% in the control group during the same period. In the case of the 3-ring and 4-ring PAHs, complete degradation in the sample and 46% - 100% degradation in control was observed after one year of the experiment. The 5-ring and 6-ring PAHs were degraded to about 77%-100% in the sample group and 26%-87% in the control group during the one year of the experiment. The study results show that biostimulation is a very effective method to improve the degradation rate of organic pollutants and PAHs (Polycyclic Aromatic Compounds) in contaminated coastal sediment.

Biological Activities in the Extract of Fermented Codonopsis lanceolata (발효더덕 추출물의 생리활성)

  • Park, Sung-Jin;Song, Seong-Won;Seong, Dong-Ho;Park, Dong-Sik;Kim, Seung-Seop;Gou, Jinyu;Ahn, Ju-Hee;Yoon, Won-Byung;Lee, Hyeon-Yong
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.38 no.8
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    • pp.983-988
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    • 2009
  • To investigate the applicability of hot water extract from Codonoposis lanceolata (CL) and fermented Codonoposis lanceolata (FCL) as functional food and cosmeceutical material, its total phenolic contents, total flavonoids, electron donating ability (EDA), SOD-like activity, nitrate-scavenging ability (NSA), reducing power were examined. Total phenolic contents of CL and FCL were 0.54 mg/100 g and 2.79 mg/100 g, respectively, and total flavonoids contents were estimated as 2.26 mg/100 g for CL and 6.16 mg/100 g FCL. The EDA of CL and FCL were 8.0$\sim$17.9% and 32.9$\sim$74.9%. The SOD-like activities of CL and FCL were 0.6$\sim$16.5% and 3.5$\sim$21.6%, respectively, and the activity was dependent on the sample concentration. The NSA was pH dependent, and was the highest at pH 1.2 and the lowest at pH 6.0. The NSA of FCL was higher than that of CL. The FCL extract showed the highest reducing power (0.65) at the concentration of 1,000 $\mu g$/mL. Based on the above results, we deemed that the FCL might have potential antioxdant activities.