• KCID journal
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• v.18 no.1
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• pp.25-32
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• 2011

In order to effectively manage the reservoir, reservoir water quality management should be based on physicochemical and configurational characteristics. In this research, correlation between factors affecting the reservoir water quality was examined. Chl-a and COD shows the highest positive correlation. Chl-a and T-P also has a high positive correlation, however Chl-a and T-N show lower correlation relatively. Even though T-N is an important factor for phytoplankton growth which increase Chl-a concentration, corelation of Ch1-a and T-N shows that enough nitrogen in the reservoir isn't no longer limiting factor. The age of reservoir can cause of increasing COD and SS. Embankment height and elevation of reservoirs shows strong negative correlation to water quality. That means reservoir which is higher embankment height and locate in higher elevations is less contaminated. Regression expression was derived with Chl-a and water quality parameters, and height of reservoir. Finally Chl-a was simulated using regression expression and it was a good approach to predict the Chl-a concentration.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.344-349
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• 2014

BACKGROUND: Purpose of the study was to establish the extinction coefficients of chlorophyll a and b in N,N-dimethylformamide(DMF) and Dimethylsulfoxide(DMSO) solvents and to find out the conditions of optimal extraction temperature and time in citrus leaves. METHODS AND RESULTS: Chlorophyll a and b standards were dissolved in DMF and DMSO. Extinction coefficients of chlorophyll pigments were determined and their contents were quantified using spectrophotometer. Chlorophyllous pigments of citrus(Citrus unshiu Marc. cv. Okitsu wase) leaves were extracted at 25, 40, 60 and $80^{\circ}C$ for 4, 6, 8, 24 and 48 hours to determine the optimal extraction condition. CONCLUSION: The extinction coefficients of chlorophyll a(Chl a) and chlorophyll b(Chl b) of DMF extracts for high extinction wavelength were 663.8 and 647.2 nm. Similarly, the high extinction wavelength of DMSO extracts were 665.8 and 649.0 nm for chl a and b respectively. Chl a, Chl b and total chlorophyll content of DMF extracts were Chl a = $12.10A_{663.8}-2.74A_{647.2}$, Chl b = $21.94A_{647.2}-5.06A_{663.8}$ and total $Chl=19.193A_{647.2}+7.04A_{663.8}$. Similarly, Chl a, Chl b and total Chl of DMSO extracts were Chl a = $14.53A_{665.8}-5.40A_{649.0}$, Chl b = $26.98A_{649.0}-7.11A_{665.8}$ and total $Chl=21.58A_{649.0}+7.43A_{665.8}$. The chlorophyll extracts of DMF and DMSO were very stable in dark. High chlorophyll contents of citrus leaves were found at $80^{\circ}C$ extraction for 6 hours in DMF and at $80^{\circ}C$ extraction for 24 hours in DMSO. However, the chlorophyll content was decreased significantly after 8 hours in DMF extraction while it was remained up to 30 hours in DMSO extraction.

• Journal of Aquaculture
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• v.19 no.4
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• pp.310-314
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• 2006

This study was carried out to investigate grazing of brackish water cyclopoid copepod Paracyclopina nana on four microalgae species (Tetraselmis suecica, Isochrysis galbana, Phaeodactylum tricornutum and Dunaliella tertiolecta) and different food concentrations raging from 5 to 55 ng chl a/ml. The grazing of P. nana was examined by the analysis of decreased number of microalgae and chlorophyll a content in rearing water and pigment content in the gut of P. nana. The maximum content of decreased chlorophyll a and gut pigment in P. nana varied with microalgae species and concentrations. It appeared at the food concentration 30 ng chl a/ml in T. suecica, 40 ng chl a/ml in I. galnaba and D. tertiolecta, and 45 ng chl a/ml in P. tricornutum, respectively. The grazing rate of a P. nana per hour also varied with different microalgae species and concentrations. The maximum grazing rate per hour of P. nana fed T. suecica with 39.3 ng chl a/ml was the highest with 0.63 ng chl a/h, but lowest with 0.52 ng chl a/h. From these results, it can be concluded that T. suecica is the best species among four microalgae species for the mass culture of P. nana and daily optimum food concentration of P. nana is $25{\sim}39$ ng chl a (approximately $10{\sim}15{\times}10^4$ cells).

• Korean Journal of Environmental Biology
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• v.41 no.1
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• pp.89-100
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• 2023

We investigated the spatial distribution of heterotrophic bacteria associated with different water masses in the northern East China Sea(ECS) in summer. The surface water masses were divided into the Changjiang Diluted Water (CDW) and high salinity water (HSW). In the CDW region, the concentrations of dissolved inorganic nitrogen (DIN) and chlorophyll-a (Chl-a), and micro Chl-a contribution were high; and bacterial abundance (BA) and ciliate abundance (CA) were also high. In the HSW region with relatively low DIN concentrations, Chl-a concentration and micro Chl-a contribution were low, but pico Chl-a contribution was increased compared to those in the CDW region. BA did not show any significant difference from the CDW region, but CA was decreased. BA showed a positive correlation with Chl-a concentration in the CDW region; however, it did not show a significant correlation with Chl-a concentration in the HSW region. The ratio of bacterial carbon biomass/phytoplankton carbon biomass was exponentially increased with a decrease in the Chl-a concentration. Compared to the past (1990-2000s), the surface phosphate concentrations and the size of dominant phytoplankton have recently decreased in the ECS. Considering this trend of nutrient decrease and miniaturization of the phytoplankton, our results indicate that changes in the strength of the oligotrophic water mass could alter the function of the microbial food web.

• BMB Reports
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• v.34 no.6
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• pp.496-501
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• 2001

Lincomycin, an inhibitor of plastid protein synthesis, was found to block the synthesis of apoprotein P700 with a molecular mass of 72 kDa and the assembly of the Chl a-protein of PS I. Synthesis of the polypeptides of 48, 43.5, and 32 kDa of the PS II complex is also suppressed. This process is accompanied by the disappearance of the PS Two reaction center Chl a at 683 nm, and of the PS One reaction center Chl a at 690, 696, and 705 nm on the fourth derivative of the absorption spectra at 77K. Lincomycin does not affect the synthesis of LHC subunits. It increases the content of the two main Chl forms of LHC at 648 nm (Chl b) and 676 nm (Chl a). The low-temperature fluorescence ratio F736/F685 is also increased. However, the effect of cycloheximide (an inhibitor of cytoplasmic protein synthesis) leads to the reduction of polypeptides of the light-harvesting Chl a/b-protein complex in the range of 29.5-22 kDa. Under these conditions, the relative amount of Chl b and the F736/ F685 fluorescence ratio decrease significantly. This is obviously the result of blocking the LHC I and LHC II synthesis. At the same time rifampicin and actinomycin D (inhibitors which block transcription in chloroplast and nuclear genome, respectively) inessentially affect the characteristics of these complexes.

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.3005-3008
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• 2014

Human ChlR1 protein (hChlR1), a member of the cohesion establishment factor family, plays an important role in the segregation of sister chromatids for maintenance of genome integrity. We previously reported that hChlR1 interacts with hFen1 and stimulates its nuclease activity on the flap-structured DNA substrate covered with RPA. To elucidate the relationship between hChlR1 and Okazaki fragment processing, the effect of hChlR1 on in vitro nuclease activities of hFen1 and hDna2 was examined. Independent of ATPase activity, hChlR1 stimulated endonuclease activity of hFen1 but not that of hDna2. Our findings suggest that the acceleration of Okazaki fragment processing near cohesions may aid in reducing the size of the replication machinery, thereby facilitating its entry through the cohesin ring.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.255-261
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• 1999

To investigate the effects of strong acidic electrolytic water on the chloroplast, barley leaves were treated with strong acidic electrolytic water(pH 2.5). And to investigate the effects of weak acidic electrolytic water on the chloroplast development, etiolated barley leaves were treated with weak acidic electrolytic water(pH 6.5) during greening period. Chl contents, Fo, Fv, and Chl fluorescence quenching coefficient in barley leaves were measured during and after treatment of acidic electrolytic water. The following results were obtained. Chl a, b, and carotenoid were decreased with treatment of strong acidic electrolytic water. Chl contents were significantly decreased than that of the control after 5 min. These results provide evidence that the strong acidic electrolytic water dissimilate the Chl and so that the value of Fo was slightly increased. The strong acidic electrolytic water damaged PS II because Fo was increased and Fv, Fm, and Fv/Fm ratio were decreased. qP, qNP and qE were decreased. On the other hand qI was increased than that of the control. But Chl content and Chl fluorescence patterns were a little changed as the pH increase over 4.0 Chl a, b, and carotenoid were increased with treatment of weak acidic electrolytic water during greening period. Chl contents were significantly increased than that of control after 12 hours greening. These results provide evidence that the weak acidic electrolytic water accelerated the chlorophyll synthesis. And the weak acidic electrolytic water accelerated PS II development because Fv, Fm, qP and Fv/Fm ratio were increased than that of the control.

• Journal of Wetlands Research
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• v.23 no.2
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• pp.144-153
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• 2021

In recently, the green algae bloom is one of the most severe challenges. The seven days prior prediction is in operation to issues the water quality warning, but it also needs a longer time of prediction to take preemptive measures. The objective of the study is to establish a method to conduct a 3-month prior prediction of Chl-a concentration in the Daechong Lake and tested its applicability as a supplementary of current water quality warning. The historical record of water quality in the Daechong Lake and seasonal forecasting of ECMWF were obtained, and its time-series characteristics were analyzed. The Chl-a forecasting model was established using a correlation between Chl-a concentration and meteorological factor and NARX model, and its efficiency was compared.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.319-337
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• 2010

Major objective of this study was to determine interannual and seasonal water quality along with characteristics of longitudinal gradients along the reservoir axis of the riverine zone (Rz)-to-lacustrine zone (Lz). Water quality dataset of five years during 2003~2007 used here were obtained from Ministry of Environment, Korea and ten physical, chemical and biological parameters were analyzed in the study. Similarity analysis, based on moropho-hydrological variables of reservoir surface area, watershed area, total inflow, and outflow, showed that the reservoirs were categorized as three groups of large-dam reservoirs (Chungju Reservoir, Daecheong Reservoir and Soyang Reservoir), mid-size reservoirs (Andong Reservoir, Yongdam Reservoir, Juam Reservoir and Hapcheon Reservoir), and small-size reservoirs (Hoengseong Reservoir and Buan Reservoir). According to the data comparison of high-flow year (2003) vs. lowflow year (2005), dissolved oxygen (DO), pH, biological oxygen demand (BOD), suspended solids (SS), total nitrogen (TN), total phosphorus (TP), chlorophyll-a (CHL) and electrical conductivity (EC) declined along the longitudinal axis of Rz to Lz and water transparency, based on Secchi depth (SD), increased along the axis. These results indicate that transparency was a function of Values of pH, DO, SS, SD, and EC at each site were greater in the low-flow year (2005) than the high-flow year (2003), whereas values of BOD, COD, TN, TP and CHL were greater in the high-flow year (2003). When values of TN, TP, CHL and SD in nine reservoirs were compared in the three zones of Rz, Tz, and Lz, values of TN, TP and CHL declined along longitudinal gradients and SD showed the opposite due to the sedimentation processes from the water column. Values of TN were not statistically correlated with TP values. The empirical linear models of TP-CHL and CHL-SD showed significant (p<0.05, $R^2$>0.04). In the mid-size reservoirs, the variation of CHL was explained ($R^2$=0.2401, p<0.0001, n=239) by the variation of TP. The affinities in the correlation analysis of mid-size reservoirs were greater in the CHL-SD model than any other empirical models, and the CHL-SD model had an inverse relations. In the meantime, water quality variations was evidently greater in Daecheong Reservoir than two reservoirs of Andong Reservoir and Hoengseong Reservoir as a result of large differences of water quality by long distance among Rz, Tz and Lz.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.309-323
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• 2020

Estimation of chlorophyll a concentration (CHL) on coastal areas using remote sensing has been mostly performed through multi-spectral satellite image analysis. Recently, various studies using hyperspectral imagery have been attempted. In particular, airborne hyperspectral imagery is composed of hundreds of bands with a narrow band width and high spatial resolution, and thus may be more effective in coastal areas than estimation of CHL through conventional satellite image. In this study, comparative analysis of hyperspectral and satellite-based CHL images was performed to estimate CHL in coastal areas. As a result of analyzing CHL and seawater spectrum data obtained by field survey conducted on the south coast of Korea, the seawater spectrum with high CHL peaked near the wavelength bands of 570 and 680 nm. Using this spectral feature, a new band ratio of 570 / 490 nm for estimating CHL was proposed. Through regression analysis between band ratio and the measured CHL were generated new CHL empirical formula. Validation of new empirical formula using the measured CHL showed valid results, with R² of 0.70, RMSE of 2.43 mg m^-3, and mean bias of 3.46 mg m^-3. As a result of applying the new empirical formula to hyperspectral and satellite images, the average RMSE between hyperspectral imagery and the measured CHL was 0.12 mg m^-3, making it possible to estimate CHL with higher accuracy than multi-spectral satellite images. Through these results, it is expected that it is possible to provide more accurate and precise spatial distribution information of CHL in coastal areas by utilizing hyperspectral imagery.