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131.
Jong Ryeol Choe Yoon Sub Shin Ji Yong Choi Tae Hwan Kim Min-Min Jung Cheol Young Choi 《Ocean Science Journal》2017,52(4):501-509
We investigated the effect of light wavelengths on antioxidant and immunity parameters in juvenile rock bream, Oplegnathus fasciatus, exposed to thermal stress (25 and 30°C). We exposed the fish to light emitting diodes (LEDs) emitting green (520 nm) and red light (630 nm) of 0.25 and 0.5 W/m2 intensity, and measured the activity, and mRNA and protein expression levels of the antioxidant enzymes, superoxide dismutase, catalase, and glutathione peroxidase. We also determined the levels of plasma hydrogen peroxide (H2O2), melatonin, and lysozyme. Furthermore, the mRNA and protein levels of caspase-3 were measured and terminal transferase dUTP nick end labeling (TUNEL) assays were performed. We observed that mRNA expression and activities of antioxidant enzymes and plasma H2O2 levels were significantly higher after exposure to high temperatures. However, increases in these parameters were significantly lower after exposure to green LED light. The plasma melatonin and lysozyme levels were significantly lower in the different groups after exposure to high temperatures; however, in groups exposed to green LED light, their levels were significantly higher than those in the control group. The expression pattern of caspase-3 mRNA was similar to that of H2O2. The TUNEL assay showed that apoptosis was markedly higher at higher water temperatures than that at 20°C. These results indicate that high water temperatures induce oxidative stress and decrease the immunity in juvenile rock bream but green LED light inhibits the rise in oxidative stress and combats the decrease in immunity and should, thus, be useful in the culture of rock bream. 相似文献
132.
Woo-seok Shin 《Environmental Earth Sciences》2017,76(22):782
The objective of the present study is to evaluate the absorption efficacy of H. fusiformis biochar (HFB) for the removal of phenol and heavy metals from single and mixed solute systems of these species under different experimental conditions. The effects of contact time, pH change, initial phenol concentration, and heavy metal concentration on the adsorption capacity of HFB were investigated. The kinetics and equilibrium models of sorption of the components of the single and mixed solute systems on HFB were also studied. The experimental data were fitted to kinetic and equilibrium models. The batch experiments revealed that 360 min of contact time was sufficient to achieve equilibrium for the adsorption of both phenol and heavy metals. The adsorption of phenol and nickel by HFB followed the pseudo-second-order kinetic model, which was quite adequate for describing the adsorption mechanism. The equilibrium data for the adsorption of phenol and heavy metals fit well to the Langmuir model with regression coefficients of R 2 > 0.819. The maximum Langmuir adsorption capacities were 10.39, 12.13, 22.25, 2.24, 2.89, and 22.03 mg/g for phenol, Ni2+, Zn2+, Cu2+, Pb2+, and Cd2+, respectively. Moreover, HFB exhibited optimal sorption under slightly acidic conditions at pH 6. The HFB used in the present study exhibited higher adsorption capacity for the removal of phenol and heavy metals from aqueous solutions compared to documented sorbents. These results demonstrate that HFB is potentially useful for alleviating the harmful effects of phenol and heavy metal in wastewater treatment systems. 相似文献
133.
Phytoplankton viability in ballast water from international commercial ships berthed at ports in Korea 总被引:1,自引:0,他引:1
We investigated the viability of phytoplankton from ballast water of international commercial ships berthed at the ports of Ulsan and Onsan, Korea. The incubation conditions used were temperatures of 13 °C to represent ambient water and 20 °C to represent the thermal optimum, as well as nutrients in ballast water, shipside water, and F/2 medium. Phytoplankton in new (∼7 days) and old (20 and 23 days) ballast water survived when incubated under the nutrients typical of shipside water and F/2 medium at 13 °C and 20 °C. Colonization process was mostly dominated by Skeletonema costatum, Cylindrotheca closterium and pennate diatoms (<10 μm in diameter). S. costatum and C. closterium were persistent during incubation time, whereas pennate diatoms dominated in the three types of media from doubling to last phase of growth. This study showed that bloom-forming and pennate diatoms appear to be the species most likely to become successfully established in the two ports. 相似文献
134.
135.
Hongjoon Shin Taesoon Kim Sooyoung Kim Jun-Haeng Heo 《Stochastic Environmental Research and Risk Assessment (SERRA)》2010,24(2):183-197
In this study, the parameter estimations for the 3-parameter generalized logistic (GL) distribution are presented based on
the methods of moments (MOM), maximum likelihood (ML), and probability weighted moments (PWM). The asymptotic variances of
the MOM, ML, and PWM quantile estimators for the GL distribution are expressed as functions of the sample size, return period,
and parameters. A Monte Carlo simulation was performed to verify the derived expressions for variances and covariances between
parameters and to evaluate the applicability of the derived asymptotic variances of quantiles for the MOM, ML and PWM methods.
The simulation results generally show good agreement with the analytical results estimated from the asymptotic variances of
parameters and quantiles when the shape parameter (β) of the GL distribution is between −0.10 and 0.10 for the MOM method and between −0.25 and 0.45 for the ML and PWM methods,
respectively. In addition, the actual sample variances and the root mean square error (RMSE) of asymptotic variances of quantiles
for various sample sizes, return periods, and shape parameters were presented. In order to evaluate the applicability of the
estimation methods to real data and to compare the values of estimated parameter, quantiles, and confidence intervals based
on each parameter estimation method, the GL distribution was fitted to the 24-h annual maximum rainfall data at Pohang, Korea. 相似文献
136.
Polychaetes are suitable organisms for evaluation of impact of sediment pollution. We evaluated toxicity of cadmium and copper and measured metallothionein-like proteins (MTLPs) in the polychaete Perinereis nuntia. At the same concentration ranges copper was unexpectedly more toxic than cadmium. Copper also caused no significant increase in MTLPs in the polychaetes. When P. nuntia and another polychaete species, Cirratulus cirratus were cultured in the contaminated sediments collected from Lake Sihwa (Korea), a high mortality of 80% was observed on day 6 in P. nuntia in the sediment with the highest metal concentration. However, no mortality was observed up to 35 days in C. cirratus in any sediment. MTLP contents between two species also varied. These findings suggest that MTLP induction response in the polychaetes varies with the metal type and species and it may be used as a biomarker of sediment pollution in the polychaetes after further validation and field trials. 相似文献
137.
138.
139.
Takehiko Mori Yasuaki Sudo Tomoki Tsutsui Shin Yoshikawa 《Bulletin of Volcanology》2008,70(9):1031-1042
Isolated-type tremors having two events with different dominant frequencies are characteristic seismological phenomena observed
during the fumarolic activity stage at Aso Volcano. These isolated tremors are called hybrid tremors (HBT) and comprise two
parts: an initial part named the “HF-part” with a dominant frequency in the high-frequency region (approximately 10 Hz) and
the following part named the “LF-part” with a dominant frequency in the low-frequency region (approximately 2 Hz). The LF-part
is observed after the HF-part, and the HBT is accompanied by a long-period tremor (LPT). Hypocenters and source parameters
are estimated using seismograms recorded at 64 stations around Nakadake crater. The amplitude distributions of all HF-parts
have almost similar trends. Similarly, the amplitude distributions of all LF-parts have almost similar trends. However, the
amplitude distributions of HF- and LF-parts are not similar. From these results, we proposed that the hypocenters and source
parameters of HF- and LF-parts are not common, but each of them have common hypocenters and source parameters. The hypocenter
region of HF-parts was estimated to be just beneath the fumarole region south of the 1st crater: the volume fluctuation is
the major source factor. The hypocenter region of LF-parts is estimated to be at a depth of approximately 300 m beneath the
first crater: the strike–slip component is the major source parameter. The hypocentral depth of LF-parts is located at the
upper end of the crack estimated to be the source of the LPTs. The LPTs and HBTs are observed almost simultaneously. We consider
that volcanic fluid is involved in the source mechanisms of both HBT and LPT. 相似文献
140.
Based on stable isotope data and carbon and sulfur elemental analyses, the sedimentary environment of the Yellow Sea was
significantly influenced by the sea level changes during the Late Quaternary. At the low sea level stand when the sea level
was lower by 56 m, the salinity of seawater was reduced to about 7.6‰, and the sedimentation rate in the central part of the
Yellow Sea was three times higher than the present rate. The high C/S ratio during the low sea level stand is strong evidence
that sedimentation took place in a lower salinity environment than exists at present.
Received: 25 September 1997 / Revision reveived: 15 June 1998 相似文献