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        검색결과 171

        141.
        1996.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국립공원에서 자연보존의 일환으로 기초자료를 축적하고자 1994년 6월부터 12월까지 3회에걸쳐 주왕산 국립공원 일대의 10개 지소에서 담수어류상을 조사한 결과 한국고유종 및 아종인 긴몰개, 점몰개, 왕종개, 수수미꾸리, 미유기, 자가사리 그리고 동사리를 포함한 6개과 17종의 담수어류를 확인하였다. 낙동강 수계에서는 14종이, 영덕 오십천 수계에서는 10종이 분포하였으며 공통적으로 분포하는 어종은 붕어, 버들치, 피라미, 갈겨니, 미꾸리, 자가사리 및 동사리로서 7종이었고 우세종은 버들치, 갈겨니 그리고 동사리였다.
        4,200원
        143.
        1995.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        충청북도 제천시의 상수도 취수를 목적으로 건설하는 취수장 예정지를 중심으로 평창강의 담수어류상을 1994년 9월 25일과 1994년 10월 7일부터 1994년 10월 9일까지 두 차례 조사하고 하천 유지수량의 변동이 어류의 생태에 미치는 영향을 조사하였다. 6개 조사 지역에서 총 6과 21속 28종의 담수어류가 관찰되었으며 천연기념물 및 한국 특산종이 많이 관찰되었다. 평창강은 사행천으로 다양한 담수어류가 서식하기에 적합한 환경과 유지수량을 갖는다. 취수를 위한 급격한 유지 수량의 감소는 평창강의 담수어류가 대부분 멸종할 우려가 매우 높다.
        4,000원
        149.
        1994.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국립공원에서 자연보존의 일환으로 기초자료를 축적하고자 1993년 5월부터 11월까지 덕유산국립공원 일대의 9개 지소에서 담수어류상을 조사한 결과 한국고유종 및 아종인 칼납자루, 긴몰개, 돌마자, 금강모치, 참종개, 미유기, 동사리를 포함한 5개과 17종의 담수어류를 확인하였다. 금강수계에서는 16종이, 낙동강수계에서는 8종이 분포하였으며 공통적으로 분포하는 어종은 긴몰개, 돌마자, 돌고기, 버들치, 갈겨니, 미꾸리 및 동사리로서 7종이었고 우세종은 버들치, 갈겨니 그리고 동사리였다. 한편 한국산 담수어의 형태에 관한 기초자료 축적의 일환으로 이지역에서 채집된 담수어 17종의 척추골수를 soft X-ray를 활용하여 그 분석결과를 보고함과 아울러 수계의 환경훼손에 따른 어류의 비정상적 골격형질 발현양상 파악결과의 활용가능성을 검토하였다.
        4,800원
        150.
        1993.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국립공원에서 자연보존의 일환으로 기초자료를 축적하기 위하여 1992년 5월부터 1992년 10월까지 소백산국립 공원 일대의 9개 지소에서 담수어류상을 조사하였다. 이 지역에는 13종의 한국고유종을 포함하여 9개 과에 속하는 27종의 담수어류가 분포하였다. 한강수계에서는 15종이 낙동강 수계에서는 17종이 분포하였고 공통적으로 분포하는 종은 6종뿐이었다. 이 지역의 우세종은 갈겨니, 피라미, 버들치 그리고 동사리였다. 갈겨니. 피라미, 버들치를 포함한 11종에서 형태적 이상을 나타낸 개체가 출현하였다, 따라서 이와 같은 양상에 대하여 구체적인 조사와 사려 깊은 대책이 절실히 요망된다.
        4,000원
        151.
        1991.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        관광개발에 따른 심한 환경변화가 예상되는 지리산 국립 공원의 어족자원을 보호하기 위한 기초자료를 얻고자 이 지역의 어류분포상을 조사하였다. 국립공원내 하천에서 확인된 어종은 잉어과, 퉁가리과 및 농어과가 포함된 3과에 속하는 4종이었다. 우점종은 갈겨니였으나 이미 보고된 자료보다는 약간 감소추세을 보이고 있다. 따라서 이 지역에 대한 각별한 보호와 분별있는 관광개발이 요망된다.
        4,000원
        155.
        2019.11 KCI 등재 서비스 종료(열람 제한)
        The National Environmental Specimen Bank (NESB) has set up a plan to develop reference materials in the facility for assuring analytical quality and validating analytical methods for its monitoring samples. Some of the crucial characteristics that reference materials must consist of are homogeneity and stability of both intra and inter-bottles. In this study, we examined the homogeneity and stability of cryogenically-milled muscle samples, from Common Carp (Cyprinus carpio) for total mercury. Homogeneity was tested using ANOVA analysis and regression analysis was used to test short-term stability. The variations of total mercury concentration did not significantly differ between the intra and the inter-bottle (F=0.8, p=0.37). Additionally, relative standard deviation of the total mercury concentration showed low values (2.28%). For the short-term stability test, total mercury variations were not statistically significant as demonstrated by the result of the regression analysis (F ratio = 3.11, p = 0.18). This suggests that the cryogenic-milling process has statistically proven the degree of homogeneity and short-term stability for samples of carp muscles in the chemical analysis for total mercury.
        156.
        2019.11 KCI 등재 서비스 종료(열람 제한)
        Environmental factors and changes in phytoplankton community structure before (August 5, 2017), during (August 18 and 25) and after (August 30 and September 15) freshwater input were analyzed to investigate the effects of freshwater input from Ganwol and Bunam lakes located in the upper part of Cheonsu Bay. Due to the large amount of freshwater input in the Cheonsu Bay, the surface salinity of the bay decreased by more than 8 psu, and the thermocline existing in the bay during August weakened. In addition, hypoxic phenomena occurred temporarily in the bay as the low oxygen water mass from the freshwater lakes flowed into the bay, and chemical oxygen demand, nutrients, and N/P increased with freshwater inflow. The density of phytoplankton during the freshwater inflow increased owing to their input from the freshwater lakes. Diatom species (Eucampia zodiacus) dominated the phytoplankton community in the bay before freshwater input; nanoflagellates, chlorophyta, cyanobacteria, and diatoms (Pseudonitzschia delicatissima, Chateocceros spp.) entered during freshwater input; and after freshwater inflow ended, diatoms (Chateocceros spp.) again became predominant indicating a return to previous conditions. The amount of phytoplankton standing crops increased sharply due to the inflow of freshwater species into the bay on the second day of discharge compared to before freshwater input; pre-discharge conditions were restored at most stations except at some sites close to the Bunam Lake three days after discharge. Therefore, the large amount of freshwater flowing into the bay affects not only the geochemical circulation in the bay but also the phytoplankton community structure. In particular, the high concentration of nutrients in the freshwater lake affect the marine ecosystem of the bay during August.
        157.
        2017.03 KCI 등재 서비스 종료(열람 제한)
        On June 14, 2008 (the first experiment) and July 24, 2008 (the second experiment), the shores of the Boseong River and the sandy beaches, Seokgok-myun, Moksadong-myun, Gokseong-gun in Jeollanam Province were investigated and a total of 29 soft-shelled turtle (Tryonyx sinensis) eggs in the natural spawning nest eggs were collected (13 eggs were collected in the first experiment and 16 eggs in the second experiment). The temperatures in the natural spawning nests were 25.9- 36.9±0.5℃, the depth of the eggs was 5.2-7.5±0.5 cm as the distance of the average 6.4±0.5 cm. 29 eggs were scattered at least 0.2 cm interval. Artificial incubation of 29 eggs was conducted in artificial nest boxes in thermo-plastic composition of the incubator, and then incubated at 26.5-35.5±0.5℃, and an average constant temperature was 31.2-32.1±1.0℃. The incubation days ranged from 53 to 55. In case of most turtles, incubation at 31℃ (higher temperatures) generally produces all or mostly females, while incubation at 25℃(cooler temperatures) produces all or mostly males. Exceptionally, in case of genus Trionyx, the sex ratio of female : male of T. sinensis of a freshwater soft-shelled turtle was approximately 1:1, which differs from other genera of turtles and makes T. sinensis Strauch only turtles presently known to lack temperature-dependent sex determination.
        158.
        2015.12 KCI 등재 서비스 종료(열람 제한)
        The response of the freshwater microalga, Chlorella vulgaris, to heavy metal stress was examined based on chlorophyll fluorescence analysis to assess the toxic effects of heavy metals in freshwater ecosystems. When toxic effects were analyzed using regular chlorophyll fluorescence analysis, photosystem II activity(Fv/Fm) decreased significantly when exposed to Cu2+ and Hg2+ for 12 h, and decreased in the order of Hg2+ > Cu2+ > Cd2+ > Ni2+ when exposed for 24h. The effective photochemical quantum yield(Φ′PSII), chlorophyll fluorescence decrease ratio(RFd), minimal fluorescence yield(Fo), and non-photochemical quenching(NPQ), but not photochemical quenching(qP), responded sensitively to Hg2+, Cu2+, and Cd2+. These results suggest that Fv/Fm, as well as Φ′PSII, RFd, Fo, and NPQ could be used to assess the effects of heavy metal ions in freshwater ecosystems. However, because many types of heavy metal ions and toxic compounds co-occur under natural conditions, it is difficult to assess heavy metal toxicity in freshwater ecosystems. When Chlorella was exposed to heavy metal ions for 12 or 24h, Fv/Fm and maximal fluorescence yield(Fm) changed in response to Hg2+ and Cu2+ based on image analysis. However, assessing quantitatively the toxic effects of several heavy metal ions is challenging.
        159.
        2013.06 KCI 등재 서비스 종료(열람 제한)
        The response of the freshwater microalga Chlorella vulgaris to mercuric ion (Hg2+) stress was examined using chlorophyll a fluorescence image analysis and O-J-I-P analysis as a way to monitor the toxic effects of mercury on water ecosystems. The levels of photosynthetic pigments, such as chlorophyll a and b and carotenoids, decreased with increasing Hg2+ concentration. The maximum photochemical efficiency of photosystem Ⅱ(Fv/Fm) changed remarkably with increasing Hg2+ concentration and treatment time. In particular, above 200 μM Hg2+, considerable mercury toxicity was seen within 2 h. The chlorophyll a fluorescence transient O-J-I-P was also remarkably affected by Hg2+; the fluorescence emission decreased considerably in steps J, I, and P with an increase in Hg2+ concentration when treated for 4 h. Subsequently, the JIP-test parameters (Fm, Fv/Fo, RC/CS, TRo/CS, ETo/CS, ΦPO, ΨO and ΦEO) decreased with increasing Hg2+ concentration, while N, Sm, ABS/RC, DIo/RC and DIo/CS increased. Therefore, a useful biomarker for investigating mercury stress in water ecosystems, and the parameters Fm, ΦPO, ΨO, and RC/CS can be used to monitor the environmental stress in water ecosystems quantitatively.
        160.
        2012.06 KCI 등재 서비스 종료(열람 제한)
        담수에서 사육한 감성돔 Acanthopagrus schlegeli(담수감성돔) 냉동/해동 정자의 생존율이 가장 높았던 결빙억제제(cryprotective agent, CPA)는 dimethyl sulfoxide(DMSO)였으며, 다음으로 glycerol, ethylene glycol(EG) 그리고 methanol 순이었다. 해동 후 정자운동성은 glycerol, DMSO, EG, methanol 순으로 높았으며, 이상의 결과들은 해수에서 사육한 감성돔(
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