• Title/Summary/Keyword: fresh water

Search Result 2,118, Processing Time 0.038 seconds

Spatial and Seasonal Patterns of Polychaete Community During the Reclamation and Dredging Activities for the Construction of the Pohang Steel Mill Company in Kwangyang Bay, Korea (광양제철소 건설을 위한 매립과 준설공사 기간중 저서 다모류 군집의 공간 및 계절 변화)

  • JUNG Rae-Hong;HONG Jae-Sang;LEE Jae-Hac
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.30 no.5
    • /
    • pp.730-743
    • /
    • 1997
  • Community structure and distribution patterns of benthic polychaetes were studied in Aug. 1983 and Feb. 1984 in Kwangyang Bay, Korea. During the study period, the large-scale reclamation and dredging operations were taking place. Polychaetes were composed of 76 species with a mean density of $342\;ind.{\cdot}m^{-2}$ during the summer 1983 and 77 species with a mean density of $437\;ind.{\cdot}m^{-2}$ during the winter 1984. Community structure indices were applied to the seasonal data. The stations influenced by the Seomjin river are characterized by a low species number and low diversity, while the stations located in channel regions represent high species richness and highdiversity. The inner bay stations showed the intermediate level in terms of species richness and diversity. On the basis of taxa composition and abundance in summer, the cluster analysis indicated that the study area was divided into live regions. The main factors that govern the polychaete distributions appeared to be the fresh water run-off and bottom sediment composition. However, a slight difference was observed in winter community, and changes in composition of the dominant species were found from Lagis bocki and Chone teres to Glycinde gurjanovae and Heteromastus filiformis. As a result, the broad scale reclamation and dredging activities may have played a role in changes of the polychaete community structure and the dominant species composition in Kwangyang Bay.

  • PDF

Origin and Developing Process of Ark-shell Culture Industry in Korea (우리나라 꼬막양식업의 발상과 발달과정)

  • BAE Su-Whan
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.19 no.1
    • /
    • pp.72-82
    • /
    • 1986
  • There were three important species among the marine organisms which were cultured in the inter tidal zone in the old days, and an ark-shell was one of them. Exaiming old books and reports concerning fishery were made in order to reveal the history and industrial trend of ark-shell culture. Ark-shell was called by the different names in the old days "Komak" and "Sohap". The name of Komak was originated in the southern coast area in the 1,700s, and from the begining of 18 century Komak was used only. Ark-shell was produced in all southern and western coast areas, where a little of fresh water flows into the calm inner sea and the intertidal zone is well developed. It was well known that ark-shells shell as well as its flesh took the effect of a medicine. Its culturing method in Korea seems to be derived from China in the beginning of 19 century, it was cultured first at the southern area of Chollanam-do. It was considered as the side business, but after Korean war it is produced on the basis of cooperative work, now its production is quite increased (more than $5,000\fra{M}{T}$) due to the goverments development policy.

  • PDF

Effect of Elevated CO2 Concentration and Temperature on the Growth and Ecophysiological Responses of Ginseng (Panax ginseng C. A. Meyer) (CO2농도와 온도증가에 따른 인삼의 생육 및 생리.생태학적 반응 연구)

  • Lee, Kyoung-Mi;Kim, Hae-Ran;Lim, Hoon;You, Young-Han
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.57 no.2
    • /
    • pp.106-112
    • /
    • 2012
  • In order to understand the growth and ecophy -siological response of ginseng to global warming condition, we cultivated one and two year ginseng seedlings in control (ambient $CO_2$ + ambient temperature) and global warming treatment (elevated $CO_2$ + elevated temperature) from March 2010 to July 2011. Shoot appearance and initiation of flowering were advanced by 3-4 days in global warming treatment than in control. However, timing of fruit setting and seed ripeness was similar in both control and global warming treatment. Shoot length was longer in global warming treatment than in control, and also the number of leaves was much in global warming treatment. Fresh root weight was not different between control and global warming treatment. Photosynthetic rate was higher in global warming treatment than at control. Photosynthetic rate and transpiration rate were higher in two year seedlings than in one year seedlings at control, but was not different between seedling age of ginseng in global warming treatment. Water use efficiency was higher in one year seedlings than two year seedlings at control and global warming treatment. These results demonstrated that Korean ginseng more or less positively responds to global warming situation.

Geochemical Characteristics of Devonian Cairn Formation in Alberta, Canada (캐나다 알버타 지역의 데본기 Cairn층의 지화학적 특성 연구)

  • Park, Myong-Ho;Kim, Ji-Hoon;Lee, Sung-Dong;Choi, Ji-Young;Kil, Yong-Woo
    • Economic and Environmental Geology
    • /
    • v.43 no.2
    • /
    • pp.85-100
    • /
    • 2010
  • Devonian Cairn Formation is one of the important hydrocarbon reservoirs in Alberta, Canada. However, the Cairn Formation, outcropped in the study area, is not prospective reservoir with poor porosity and permeability by some late diagenetic processes. In this study, geochemical characteristics of the Cairn Formation were studied to use these preliminary results for advanced geological and geophysical petroleum explorations in the near future. Rock-Eval pyrolysis showed that total organic carbon content is less than 0.3 wt.%, indicating a minor amount of bitumen and/or other hydrocarbons. The carbonates in the Cairn Formation are mainly composed of subhedral and anhedral dolomites. Pore sizes in the carbonate are various, ranging from nanometer to micrometer. Clastic sediments increase in the upper and lower parts of the Cairn Formation, probably due to changing its depositional conditions. The Cairn Formation can also be divided into several intervals based on Ca/Mg ratio in dolomite and degree of amount of calcite. These could be formed by different sedimentary environment, degree of cementation and recrystallization, different saline/fresh water, etc.

Distribution Characteristics of DEHA, Carbaryl, and Amitrole in the Fishes and Amphibians from the Major River Systems of Korea (우리나라 주요 수계에 서식하는 어류 및 양서류 체내에 함유된 DEHA, Carbaryl, Amitrole의 분포특성)

  • Joo, Yeo Jeong;Kim, Hye Sook;Kim, Young Bok;Moon, Ji Yong;Jeong, Gi Ho
    • Analytical Science and Technology
    • /
    • v.15 no.2
    • /
    • pp.149-156
    • /
    • 2002
  • In this study, the levels of DEHA, carbaryl, and amitrole contained in the fresh water fishes and amphibians were determined. The 31 sampling sites were selected including 29 sites along the several rivers and 2 sites from the well-known wet lands. The rivers consists of the Han, Nakdong, Kum, Youngsan, and other small scaled rivers. DEHA was detected from 10 sites, but carbaryl and amitrole were not detected at any sites. The highest average concentration of DEHA was determined from the Kum River by $52.7{\mu}g/kg$. In the detected 10 sites, the average concentration of DEHA from fishes was $40.0{\mu}g/kg$, and that from amphibians was $8.90{\mu}g/kg$ which indicates that 5 times more DEHA was observed from fishes than amphibians. The detection frequency from fishes was 10/62 while that from amphibians was 2/62, and the highest concentration from fishes was $95.5{\mu}g/kg$ (crucians from Kongjoo) and that from amphibians was $12.1{\mu}g/kg$ (bullfrog from Najoo). Among the 10 detected sites, 6 sites were agricultural area and the other 4 sites were semi-urban area.

Behaviour of the soil residues of the bipyridylium herbicide, [$^{14}C$]paraquat in the micro-ecosystem (Micro-ecosystem중 bipyridylium 제초제 paraquat 토양잔류물의 행적)

  • Kwon, Jeong-Wook;Lee, Jae-Koo
    • The Korean Journal of Pesticide Science
    • /
    • v.3 no.1
    • /
    • pp.66-77
    • /
    • 1999
  • In order to elucidate the fate of the residues of the bipyridylium herbicide paraquat in soil, maize plants were grown for 4 weeks on the specially-made pots filled with two different types of soils containing fresh and 6-week-aged residues of [$^{14}C$]paraquat, respectively. The mineralization of [$^{14}C$]paraquat to $^{14}CO_{2}$ during the aging period and the cultivation period of maize plants amounted to $0.13{\sim}0.18%$ and $0.02{\sim}0.17%$, respectively, of the original $^{14}C$ activities. At harvest the roots and shoots contained less than 0.1% and 0.01% of the originally applied $^{14}C$ activities, respectively, whereas the $^{14}C$ activities remaining in soil were more than 97% in both soils. The water extractability of the soil where maize plants were grown for 4 weeks was less than 1.2% of the original $^{14}C$ activities. Most of the non-extractable soil-bound residues of [$^{14}C$]paraquat were incorporated into the humin fraction. Soil pHs during the aging of soil B and after cultivation in all treatments increased. The distribution of the $^{14}C$ activities in subcellular particles of the maize plant roots was the highest in the residue fraction(incompletely homogenized tissue). Dehydrogenase activities increased after vegetation, regardless of soil aging.

  • PDF

The production and characterization of anti-Naegleria fowleri monoclonal antibodies (Naegleyiu fowleri에 대한 단세포군 항체의 생산과 그 특성에 관한 연구)

  • 류재숙;임경일
    • Parasites, Hosts and Diseases
    • /
    • v.30 no.1
    • /
    • pp.33-42
    • /
    • 1992
  • Naegleria fowleri, a free-living amoeba commonly found in moist soil and fresh water, enters the body via the nasal mucosa and migrates along the olfactory nerve to t he brain, where it causes acute amoebic meningoencephalitis. In the present study 7 clones secreting monoclonal antibodies (McAbs) against N. fowleri were produced and the effector function of them was investigated. Their isotopes were IgGl (Nf 1, Nf 154), 19G3 (Nf 137) and 19A (Nf 1, Nf 2, Nf 256, Nf 279). Five McAbs (McAb Nf 2, Nf 279, Nf 27, Nf 154, Nf 137) were specific for N. fowleri by ELISA and recognized the antigenic determinants located on the trophoBoite surface by IFAT and immunoperoxidase stain. These aye McAbs had capacity to agglutinate N. fowleri trophozoites and inhibited the growth of the amoeba in culture medium. McAb Nf 2 inhibited proliferation of trophozoites in vitro significantly. Also the cytotoxicity of JV. fowleri against CHO cell was reduced in the presence of McAb Nf 2 and McAb Nf 154. From these results McAb Nf 2 was confirmed to weaken the virulence of the amoeba among 7 screened McAbs.

  • PDF

Epidemiological studios on Metagonimus infection along the Hongcheon river, Kangwon Province (강원도 홍천강 유역의 Metagonimus속 흡충 감염상)

  • 안영훈;양용석
    • Parasites, Hosts and Diseases
    • /
    • v.26 no.3
    • /
    • pp.207-214
    • /
    • 1988
  • The Hongcheon river system knows down through the Hongcheon area of Kangwon-do, and reaches to the Cheongpyeong "Dam in Kyonggi.do. Stool specimens from the inhabitants residing along the Hongcheon river basin were examined to detect infection rates of Metagonimus sp. , and the intermediate hosts were collected to detect larval stages. The results obtained were as follows: 1. Thirty-nine (33 males and 6 females) out of 529 (314 males and 215 females) inhabitants were infected with Metagonimus sp., showing a total positive rate of 7.4%. 2. In eight areas surveyed, the specimens from Kulji.ri of Bukbang-myon at the middle part of the river showed the highest positive rate of 26.9% (14 positives out of 52) (males; 38.2%), The specimens from Mogog-ri of Seo-myon at the downstream of the river showed a positive rate of 10.4%(13 positives out of 125) (males; 12.6%). The positive rates in other regions were less than 10%. 3. The density of the first intermediate host, Semisulcospira sp., was the highest in Kulji.ri of Bukbang-myon (10~20 snails per $m^2$), and the infection rate of Metagonimus cercariae in the snails was 10.7%(13 positives out of 121 snails). 4. The infection rate of Metagonimus metacercariae in Zacco platypus, the freshwater Bish favorably eaten raw by the inhabitants, was 68.25 (30 positives out of 44 fishes), and most metacercariae were detected under the scales (89.95). 5. Adult flukes were obtained from the small intestine of a rat, 15 days after infection with the metacercariae obtained from Z. platypus. These adult cukes were identified to be the same species as thcse obtained from human hosts. By this survey, new endemic areas of Metagonimus infection were discovered along the Hongcheon river basin and the main source of infection was the fresh water ash, Z. platypus.

  • PDF

Changes in Physicochemical Properties of Paprika by Intense Pulsed Light Treatment (광펄스 처리에 의한 파프리카의 이화학적 변화)

  • Hong, Hee Joung;Kim, Ae-Jin;Park, Hee Ran;Shin, Jung-Kue
    • Korean Journal of Food Science and Technology
    • /
    • v.45 no.3
    • /
    • pp.339-344
    • /
    • 2013
  • Application of intense pulsed light (IPL) treatment is an emerging technology with interesting prospects in food preservation. However, information concerning the factors affecting the inactivation of microorganisms and their impact on the quality of fresh-cut food is scarce. In this study, the effects of IPL treatment on the microbial inactivation and physicochemical change in paprika were determined. The viability of bacteria in paprika treated with IPL decreased slightly with the treatment time. In addition, water content was slightly decreased after IPL treatment regardless of the color of paprika. However, except in red paprika, sugar content increased after IPL treatment. The pH of paprika increased in all samples, and the polyphenol content decreased with treatment time, but these differences were very small. After IPL treatment of paprika, vitamin C content increased in yellow and red samples. Hunter color values-lightness (L), redness (a), and yellowness (b)-increased in red paprika, but all values decreased in orange paprika.

Anti-oxidant, Anti-coagulation, and Anti-platelet Aggregation Activities of Black Currant (Ribes nigrum L.) (블랙커런트의 항산화, 항응고 및 혈소판 응집저해 활성)

  • Kim, Mi-Sun;Sohn, Ho-Yong
    • Journal of Life Science
    • /
    • v.26 no.12
    • /
    • pp.1400-1408
    • /
    • 2016
  • The black currant (Ribes nigrum L.) is belong to the Grossulariaceae family, and has piquant berries, which can be eaten as raw or as processed foods, such as jams, jelly, juice and syrups. In this study, the fresh juice of black currant (FJBC) from Austria and its subsequent organic solvent fractions, such as hexane fraction, ethylacetate (EA) fraction, butanol fraction and water residue, were prepared and their in-vitro anti-oxidant, anti-coagulation and anti-platelet aggregation activities were evaluated. The FJBC and EA fraction, which has concentrated polyphenol and flavonoid, showed strong radical scavenging activities and reducing power. The $RC_{50}s$ of EA fraction against DPPH anion, ABTS cation, nitrite were 136.3, 66.2 and $115.5{\mu}g/ml$, respectively, those are 1/10, 1/16, and 1/7.7 of $RC_{50}s$ of vitamin C. In anti-coagulation assay, the FJBC, EA and butanol fraction showed significant inhibitory activities against thrombin, prothrombin and coagulation factors. Furthermore, the anti-platelet aggregation activities of EA and butanol fraction were the stronger than that of aspirin. The concentrations required for 50% platelet aggregation inhibition of aspirin, EA and butanol fraction were 0.395, 0.192 and 0.261 mg/ml, respectively. The EA and butanol fraction have no hemolysis activities up to 0.5 mg/ml against human red blood cells. The results suggest that the FJBC and its EA and butanol fraction have high potentials as novel anti-thrombosis agents. This report provides the first evidence of anti-thrombosis activity of black currant.