• Title/Summary/Keyword: water

Search Result 99,643, Processing Time 0.123 seconds

Seasonal Variations of Nitrifying Bacteria in Agricultural Reservoir (농업용 저수지에서의 질화세균의 계절적인 변화)

  • Lee, Hee-Soon;Lee, Young-Ok
    • Korean Journal of Ecology and Environment
    • /
    • v.35 no.3 s.99
    • /
    • pp.152-159
    • /
    • 2002
  • The seasonal variations of nitrifying bacterial population sampled from 3 sites in Moon-Chon reservoir were analyzed by in situ hybridization with fluorescently labeled rRNA-targeted oligonucleotide probes from August 2000 until July 2001. In addition, physico-chemical parameters such as temperature, pH, chi-a and DOC were measured to determine correlations between those factors and the size of nitrifying bacterial populations. Total bacterial numbers varied in the range of $0.8{\sim}1.5{\times}10^6\;cells/ml$ independent of sites and had the maximal values in March at all 3 stations. The ratio of eubacteria to total bacteria ranged from 44.9% to 79.5%, and the ratio of each nitrifying bacteria to eubacterial numbers reached only $1.0{\sim}7.4%$. The variations of ammonia-oxidizing bacteria ranged from $1.1{\times}10^4$ to $3.0{\times}10^4\;cells/ml$ without noticeable peak values whereas those of nitrite-oxidizing bacteria varied in $1.3{\sim}5.7{\times}10^4\;cells/ml$ with the increasing tendency in winter regardless of the sites. Moreover it was observed that the numbers of nitrite-oxidizing bacteria were higher than those of ammonia-oxidizing bacteria. Total bacterial numbers correlated with water temperature (r = 0.355, p<0.05) and DOC (r = 0.58G, p<0.01) positively whereas nitrite-oxidizing bacteria correlated with temperature (r = -0.416, p<0.05) and pH (r = -0.568, p = 0.001) negatively. In addition, DOC represented good correlations with eubacterial numbers (r = 0.448, p<0.01). These results indicate that temperature, DOC and pH might be one of the main factors affecting variations of bacterial populations in the aquatic ecosystem. It was also suggested that FISH method is a useful tool for detection of slow growing nitrifying bacteria.

Limnological Characteristics and Influences of Free-floating Plants on the Woopo Wetland during the Summer (하계우포습지의 육수학적 특성 및 부유수생식물의 영향)

  • Joo, Gea-Jae;Kim, Gu-Yeon;Park, Sung-Bae;Lee, Chan-Woo;Choi, Sang-Ho
    • Korean Journal of Ecology and Environment
    • /
    • v.35 no.4 s.100
    • /
    • pp.273-284
    • /
    • 2002
  • During January 1998-October 1999, the impact of free-floating plants (FFP) on limnology of the wetland ecosystem was evaluated through the investigation of physicochemical characteristics of the Woopo Wetland along with in situ manipulation experiments of aquatic plants. Flooding events occurred in the wetland during the summer period (Jun.-Aug.) and water levels rose to 2-3 m due to precipitation from the catchment and inflow from the main channel of the Nakdong River. Physicochemical parameters and plankton dynamics in the wetland during the summer were greatly influenced by floods and growth of free-floating plants. Dissolved oxygen (Jun.-Sept., 4.5${\pm}$2.5 mg/1; Oct.-May, 8,1 ${\pm}$4.0 mg/1) and pH (Jun.-Sept., 6.9${\pm}$0.4; Oct.-May,7.4${\pm}$0.8) levels were significantly lower during the summer than any other seasons. Three types of enclosure experiments (100 L, treatments with floating plants, screened and opened) were conducted under the presence and absence of sediment for 15 days in the 1999 summer. The treatments with sediment had higher levels of nutrient concentrations than those of the others. Among the treatments with sediment, nutrient concentrations in the treatments with free-floating plants were higher than the others. Zooplankton communities in each treatment showed a similar variation, although the scale of zooplankton densities differed. Rotifer community dominated the zooplankton at the initial phase of the experiment, but decreased drastically along with an increase of cladoceran and copepod communities. In conclusion, low levels of dissolved oxygen and pH in the Woopo Wetland during the summer seemed to be caused by a proliferation of free-floating plants and active decomposition process at the bottom of the sediment.

Combined Effects of Filter-feeding Bivalve and Zooplankton on the Growth Inhibition of Cyanobacterium Microcystis aeruginosa (남세균 제어를 위한 동물플랑크톤(Daphnia magna)과 패류(Unio douglasiae)의 단독 및 혼합적용)

  • Kim, Nan-Young;Park, Myung-Hwan;Hwang, Su-Ok;Kim, Baik-Ho;Hwang, Soon-Jin
    • Korean Journal of Ecology and Environment
    • /
    • v.48 no.2
    • /
    • pp.108-114
    • /
    • 2015
  • Single - and combined effects of a domestic freshwater bivalve Unio douglasiae (7.6~8.6 cm in shell length) and zooplankton Daphnia magna (1~2 mm in body size) were examined to understand whether they inhibit the growth of harmful cyanobacterial bloom (i.e. Microcystis aeruginosa) in a eutrophic lake. The experiments were triplicated with twelve glass aquaria (40 L in volume); three aquaria without mussel and zooplankton, served as a control, three zooplankton aquaria (Z, density=40 indiv. $L^{-1}$), three mussel aquaria (M, density=0.5 indiv. $L^{-1}$), and three mussel plus zooplankton aquarium (ZM, density=40 indiv.Z $L^{-1}$ plus 0.5 indiv.M/L), respectively. Algal growth inhibition (%) calculated as a difference in the concentration of chlorophyll-a (Chl-a) before and after treatment. Chl-a in all aquaria decreased with the time, while a greatest algal inhibition was seen in the ZM aquaria. After 24 hrs of incubation, Chl-a concentration at the mid-depth (ca. 15 cm) in ZM aquaria reduced by 90.8% of the control, while 63.2% and 79.8% in Z and M aquaria, respectively. Interestingly, during the same period, the surface Chl-a was diminished by 51.9% and 65.4% relative to the control in Z and ZM aquaria, while 27.4% of initial concentration decreased in M aquarium, respectively. These results suggest that 1) this domestic freshwater filter-feeding bivalve plays a significant role in the control of cyanobacterial bloom (M. aeruginosa), and 2) the combination with zooplankton and mussel has a synergistic effect to diminish them, compared to the single treatment of zooplankton and mussel.

Feeding Behavior of Crustaceans (Cladocera, Copepoda and Ostracoda): Food Selection Measured by Stable Isotope Analysis Using R Package SIAR in Mesocosm Experiment (메소코즘을 이용한 지각류, 요각류 및 패충류의 섭식 성향 분석; 탄소, 질소 안정동위원소비의 믹싱모델 (R package SIAR)을 이용한 정량 분석)

  • Chang, Kwang-Hyeon;Seo, Dong-Il;Go, Soon-Mi;Sakamoto, Masaki;Nam, Gui-Sook;Choi, Jong-Yun;Kim, Min-Seob;Jeong, Kwang-Seok;La, Geung-Hwan;Kim, Hyun-Woo
    • Korean Journal of Ecology and Environment
    • /
    • v.49 no.4
    • /
    • pp.279-288
    • /
    • 2016
  • Stable Isotope Analysis(SIA) of carbon and nitrogen is useful tool for the understanding functional roles of target organisms in biological interactions in the food web. Recently, mixing model based on SIA is frequently used to determine which of the potential food sources predominantly assimilated by consumers, however, application of model is often limited and difficult for non-expert users of software. In the present study, we suggest easy manual of R software and package SIAR with example data regarding selective feeding of crustaceans dominated freshwater zooplankton community. We collected SIA data from the experimental mesocosms set up at the littoral area of eutrophic Chodae Reservoir, and analyzed the dominant crustacean species main food sources among small sized particulate organic matters (POM, <$50{\mu}m$), large sized POM (>$50{\mu}m$), and attached POM using mixing model. From the results obtained by SIAR model, Daphnia galeata and Ostracoda mainly consumed small sized POM while Simocephalus vetulus consumed both small and large sized POM simultaneously. Copepods collected from the reservoir showed no preferences on various food items, but in the mesocosm tanks, main food sources for the copepods was attached POM rather than planktonic preys including rotifers. The results have suggested that their roles as grazers in food web of eutrophicated reservoirs are different, and S. vetulus is more efficient grazer on wide range of food items such as large colony of phytoplankton and cyanobacteria during water bloom period.

Research Trend of Biomass-Derived Engineering Plastics (바이오매스 기반 엔지니어링 플라스틱 연구 동향)

  • Jeon, Hyeonyeol;Koo, Jun Mo;Park, Seul-A;Kim, Seon-Mi;Jegal, Jonggeon;Cha, Hyun Gil;Oh, Dongyeop X.;Hwang, Sung Yeon;Park, Jeyoung
    • Applied Chemistry for Engineering
    • /
    • v.31 no.2
    • /
    • pp.115-124
    • /
    • 2020
  • Sustainable plastics can be mainly categorized into (1) biodegradable plastics decomposed into water and carbon dioxide after use, and (2) biomass-derived plastics possessing the carbon neutrality by utilizing raw materials converted from atmospheric carbon dioxide to biomass. Recently, biomass-derived engineering plastics (EP) and natural nanofiber-reinforced nanocomposites are emerging as a new direction of the industry. In addition to the eco-friendliness of natural resources, these materials are competitive over petroleum-based plastics in the high value-added plastics market. Polyesters and polycarbonates synthesized from isosorbide and 2,5-furandicarboxylic acid, which are representative biomass-derived monomers, are at the forefront of industrialization due to their higher transparency, mechanical properties, thermal stability, and gas barrier properties. Moreover, isosorbide has potential to be applied to super EP material with continuous service temperature over 150 ℃. In situ polymerization utilizing surface hydrophilicity and multi-functionality of natural nanofibers such as nanocellulose and nanochitin achieves remarkable improvements of mechanical properties with the minimal dose of nanofillers. Biomass-derived tough-plastics covered in this review are expected to replace petroleum-based plastics by satisfying the carbon neutrality required by the environment, the high functionality by the consumer, and the accessibility by the industry.

Effects of Sprinkler and Fan Cooling System in Loose Barn on the Physiological Parameter and Milk Productivity in Holstein Cows During Summer (개방식우사내 Fan과 Sprinkler설치가 착유우의 생리적 변화 및 유생산성에 미치는 영향)

  • 정태영;이현민;김종민;김동일;이연섭;이인형
    • Journal of Animal Environmental Science
    • /
    • v.2 no.1
    • /
    • pp.41-52
    • /
    • 1996
  • This experiment was carried out to study the effect of sprinkler and fan cooling system on the physiological parameter, milk production and milk composition for Holstein cows in hot, humid climates. Thirty cows were assigned to one of two sections of open-sided loose barn. Water nozzles of sprinkler system were spaced in line at 1.2m intervals. Forced air was provided by 85cm diameter fans at rate of 3.4㎥/sec. The results obtained from these experiments are as follows: 1. There was no significant difference in meteorological data between control and fan + sprinkler cooling system(treatment group). 2. Skin temperature and rectal temperature of the treatment group were significantly lower than those of the control group (32.96 : 39.53$^{\circ}C$ vs 34.02 : 41.21$^{\circ}C$ respectively) (P<0.05). 3. Serum cortisol concentration of the treatment group(0.90$\mu\textrm{g}$/dL) was lower than that of control group(1.44$\mu\textrm{g}$/dL)(P<0.05). 4. Milk production of cows cooled with a sprinkler and fan cooling system was significantly higher than that of no cooling system (P<0.0l). 5. Lactose, protein and solid-not-fat content of milk were not changed by the treatments. Milk fat content of the control(3.23%) was low compared with the treatment group(3.38%). Somatic cell count was reduced by 26.63% in the treatment. The results indicate that a sprinkler and fan cooling systems can provide an effective means to relieve heat stress and enhance productivity of lactating Holstein cows during hot and humid summer season.

  • PDF

Evaluation on Heating Effects of Geothermal Heat Pump System in Farrowing House (지열 난방시스템을 이용한 분만돈사의 난방효과 분석)

  • Choi, H.C.;Park, Jae-Hong;Song, J.I.;Na, J.C.;Kim, M.J.;Bang, H.T.;Kang, H.G.;Park, S.B.;Chae, H.S.;Suh, O.S.;Yoo, Y.S.;Kim, T.W.
    • Journal of Animal Environmental Science
    • /
    • v.16 no.3
    • /
    • pp.205-215
    • /
    • 2010
  • Geothermal heat pump system (GHPS) is an energy-efficient technology that use the relatively constant and renewable energy stored in the earth to provide heating and cooling. With the aim of using GHPS as a heating source, it's possibilities of application in farrowing house were examined by measuring environmental assessment and sow's performance. A total of 96 sows were assigned to 2 pig housings (GHPS and conventional housing) with 48 for four weeks in winter season. During the experimental period, indoor maximum temperature in GHPS-housing was measured up to $26.7^{\circ}C$, average temperature could maintain $21.2^{\circ}C$. The mean value of dust levels and $CO_2$, $NH_3$ and $H_2S$ gas emissions were decreased in GHPS-housing compare with those of conventional housing. Litter size, birth weight, parity and weaning weight did not differ between housings. However, feed intake of sow in GHPS-housing was lower than that of conventional housing. In energy consumption for heating, electric power consumption increased in GHPS-housing than the conventional housing, a 2,250 kwh increase, whereas there is no fuel usage for heater in GHPS-housing. Amount of ground water circulated for heating in cold weather for earth heat exchanger was 8.4-12.9 ton per day. In conclusion, GHPS may have environmental benefits and effectiveness of heating in farrowing housing and affect the performance in sows.

A Study on Physical Properties About Velvet Antler of the Elk(Cerus canadensis) (엘크 녹용의 물성 특성에 관한 연구)

  • Sung, S.H.;Han, J.H.;Kim, Y.M.;Kim, B.K.
    • Journal of Animal Environmental Science
    • /
    • v.13 no.3
    • /
    • pp.201-210
    • /
    • 2007
  • In this study, physical properties of Elk antler was investigated to develop the optimum drying and packaging methods for improving the antler quality as well as deal with diversify of demand. After the antler was sliced with 5 mm thickness, and the compressive, shear, and tensile stresses were measured at the center and velvet parts of pre-dried and dried antlers after the contained water rate of the dried antlers was maintained below 10%. The results are as follows. 1. Considering the center of pre-dried antlers, the compressive stresses were $60.73\;g/mm^2$, $145.65\;g/mm^2$, and $260.97\;g/mm^2$, respectively at the upper, middle, and lower parts while $70.67\;g/mm^2$, $811.90\;g/mm^2$, $3,235.52\;g/mm^2$, respectively for velvet layer. Considering the center of dried antlers, the compressive stresses were $190.43\;g/mm^2$, $445.81\;g/mm^2$, and $705.86\;g/mm^2$, respectively at the upper, middle, and lower parts while $734.01\;g/mm^2$, $1,238.40\;g/mm^2$, $4,134.03\;g/mm^2$, respectively for velvet layer. 2. For the pre-dried, the shear stresses were $50.24\;g/mm^2$, $294.44\;g/mm^2$, and $423.47\;g/mm^2$, respectively, and $124.14\;g/mm^2$, $367.69\;g/mm^2$, and $425.86\;g/mm^2$, respectively for the dried antlers. 3. The tensile stresses were $13.59\;g/mm^2$, $62.85\;g/mm^2$, and $112.07\;g/mm^2$, respectively for the pre-dried and $77.24\;g/mm^2$, $175.87\;g/mm^2$, and $184.06\;g/mm^2$, respectively for the dried antlers. 4. In the case of drying antlers, the physical characteristics of the antlers was. changed such as moisture evaporation, contraction, and surface hardening. For the center part, the changes of the physical characteristics were more significant at the lower part while at the upper part for the velvet layer. 5. The stress changes of Elk antlers was shown very remarkably according to growth point. Moreover, the stress was clearly higher at velvet layer part to the center part, base parts compared to the upper parts.

  • PDF

The Effects of Feeding Feed Additives Containing Microorganisms on Characteristics of Excreta in Finishing Pigs (비육돈에 미생물제제 급여시 분뇨 특성에 미치는 효과)

  • Kwag, J.H.;Choi, D.Y.;Park, Ch.H.;Kim, J.H.;Jeong, K.H.;Yang, Ch.B.;Yoo, Y.H.;Chen, H.S.;La, C.S.
    • Journal of Animal Environmental Science
    • /
    • v.13 no.3
    • /
    • pp.153-160
    • /
    • 2007
  • Study for the effect of three different microbial feed additives(henceforth MA-A, MA-B, and MA-C) on feed coversion rate, and physical and chemical characteristics of swine finisher was conducted. MA-B had higher number of Lactobacillus spp. and yeast, compared to any other. The amylase activity of MA-B was also higher than any other. The daily feed intake rates of pigs fed control, MA-A, MA-B and MA-C were 3.15, 3.14, 3.31 and 3.42 kg, respectively. MA-C had the highest weight gain. However, there was no significant difference between treatments. The weights of feces daily excreted by pigs fed control, MA-A, MA-B, and MA-C were 2.14, 2.02, 2.18, and 2.23 kg/day, respectively. The volume of urine daily excreted by pigs fed control, MA-A, MA-B, and MA-C were 3.14, 3.26, 3.27, and $3.41\;{\ell}/day$, respectively. Water content, T-N, $P_{2}O_{5}$, and $K_{2}O$ in swine manure were not significantly different between treatments. The BOD were between 42,576 and $67,450\;mg/{\ell}$ for feces and were between 5,882.5 and $8,657.5\;mg/{\ell}$ for urine, respectively. The SS were between 138,000 and $180,000\;mg/{\ell}$ for feces and were between 875.0 and $1450.0mg/{\ell}$ for urine, respectively.

  • PDF

Effect of Levels of Total Neutral Detergent Fiber and Forage-derived Neutral Detergent Fiber on Feed Intake and Milk production in Holstein Dairy Cows (홀스타인 착유우에서 중성세제불용섬유소의 수준과 조사료유래 중성세제불용섬유소의 수준이 사료섭취량 및 유생산성에 미치는 영향)

  • Lee, Do Hyung;Kwon, Chan Ho;Kim, Eun Joong;Kim, Hyun-Jin;Kim, Gyeom-Heon;Kim, Soo-Ki
    • Journal of The Korean Society of Grassland and Forage Science
    • /
    • v.33 no.4
    • /
    • pp.304-312
    • /
    • 2013
  • This study was conducted to investigate the effect of total neutral detergent fiber (NDF) and forage-derived NDF (fNDF) on nutrient intake and milk production in Holstein dairy cows. Thirty-six Holstein dairy cows at weeks 4 to 20 of lactation were included in this study. The cows were arranged in a randomized complete block design and assigned to one of six diets: 1) 38% NDF with 18% fNDF (HN-HF); 2) 38% NDF with 15% fNDF (HN-MF); 3) 38% with 12% fNDF (HN-LF); 4) 34% NDF with 18% fNDF (LN-HF); 5) 34% NDF with 15% fNDF (LN-MF); and 6) 34% with 12% fNDF (LN-LF). The cows were fed a total mixed ration twice daily (07:00 and 18:00 h) and given ad libitum access to feed and water throughout the experiment. Data on the intake of nutrients (DM, NEl, CP, NDF, fNDF, NFC), milk yield, composition, fat-corrected milk (FCM), fat and protein corrected milk (FPCM), and energy corrected milk (ECM) were analyzed. Lower dietary concentrations of total NDF or fNDF resulted in an increase in DM, NEl, and NFC intake (p<0.01), milk yield (p<0.05) and a lower milk fat concentration (p<0.01). The LN treatment showed no significant differences in milk fat concentration compared to the HN however, further reduction in fNDF decreased milk fat content (p<0.01). The lowest level of milk fat was observed in the LN-LF diet group. Changes in the dietary concentrations of NDF or fNDF did not affect the concentrations of milk protein or SNF (solid not fat), although the yield of milk protein and SNF increased with higher milk yield (p<0.01). The level of fNDF influenced the level of FCM (p=0.07), as well as FPCM and ECM yield (p<0.05). A highly positive correlation between fNDF intake and milk fat concentration was observed in animals with low NDF compared to those offered high NDF. A strong correlation was also observed between milk yield and low NDF intake compared to high NDF intake.