• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.56-60
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• 1998

Radish and Chinese cabbage were cultivated under hydrophonic culture to investigate the effect of chromium on germination, cell elongation, ${\alpha}$-amlyase activity, contents of chlorophyll and protein. With increasing concentration of cromium, germination, cell elongation, ${\alpha}$-amlyase activity were decreased in both radish and Chinese cabbage, the rate was higher in radish than in Chinese cabbage. Contents of chlorophyll a and b were also decreased and chlorophyll a was higher than chlorophyll b. As the concentration of chromium was increased inhibited in the order of protein> ${\alpha}$-amylase activity>chlorophyll a>chlorophyll b.

• Fisheries and Aquatic Sciences
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• v.11 no.4
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• pp.212-218
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• 2008

Time series changes in the chlorophyll $\alpha$ concentrations before and after the ship Prestige oil spill on 13 November 2002 were analyzed using NCEP wind data and ocean color data. Following the oil spill, southwesterly winds pushed the oil towards the Spanish coast. In addition, the daily chlorophyll $\alpha$ concentration decreased dramatically from the middle of November to the end of December 2002, with the minimum value being recorded in December. Additionally, the mean chlorophyll $\alpha$ concentration in November and December 2002 was lower than the average value recorded for the same months from 2000 to 2005; however, with the exception of 2000, the concentration was higher in October 2002 before the spill and in January-March 2003 after the spill during the same period from 2000 to 2005.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.3
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• pp.36-45
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• 2006

By analyzing the sea surface temperature (SST), chlorophyll ${\alpha}$, zooplankton and Orview/SeaWiFS satellite data in the Korean Waters from 1999 to 2001, we studied the seasonal and annual variation of chlorophyll ${\alpha}$ concentration and zooplankton biomass. Sea surface temperature was fluctuated with the typical seasonal variation in the waters of temperate zone. Chlorophyll ${\alpha}$ concentration and zooplankton biomass were high in spring and autumn. Year to year fluctuations on annual averaged chlorophyll ${\alpha}$ concentrations in Korean Waters in the spring from 1999 to 2001 were decreased continuously. On the other hand, the estimated chlorophyll ${\alpha}$ concentrations derived from SeaWiFS ocean color data were lower than the measured sea surface chlorophyll a in the Korean Waters.

• Journal of the Korean earth science society
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• v.30 no.2
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• pp.234-246
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• 2009

Characteristics of speckle errors of Sea-viewing Wide Field-of-view Sensor (SeaWiFS) chlorophyll-${\alpha}$ concentration were analyzed, and its causes were investigated by using SeaWiFS data in the East Sea from September 1997 to December 2007. The speckles with anomalously high concentrations were randomly distributed and showed remarkably high bias of greater than $10mg/m^3$, compared with their neighboring pixels. The speckles tended to appear frequently in winter, which might be related to cloud distribution. Ten-year averaged cloudiness of winter was much higher over the southeastern part, with frequent speckles, than the northwestern part of the East Sea. Statistical analysis results showed that the number of the speckles was increased as cloudiness increased. Normalized water-leaving radiance of the speckle pixel was considerably low at the short wavelengths (443, 490, and 510 nm), whereas the radiance at 555 nm band was normal. These low measurements produced extraordinarily high concentration from the chlorophyll-${\alpha}$ estimation formula. This study presented the speckle errors of SeaWiFS chlorophyll-${\alpha}$ concentration in the East Sea and suggested that more reliable chlorophyll-${\alpha}$ data based on appropriate ocean color remote sensing techniques should be used for the oceanic application researches.

• Korean Journal of Ecology and Environment
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• v.41 no.4
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• pp.485-489
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• 2008

Algal chlorophyll-$\alpha$ is commonly determined by spectro-photometric method using 90% acetone as solvents. However, acetone has low extraction efficiency without grinding filters, and DMF (dimethyl formamide) was tested for the compatibility with acetone. Chlorophyll-$\alpha$ concentration was determined for samples from 5 reservoirs of different trophic states and phytoplankton composition, using acetone extraction with grinding and DMF without grinding. Chlorophyll-$\alpha$ measured by DMF and Acetone did not show a significant difference when using trichromatic method of UNESCO and Lorenzen, and therefore, DMF can substitute acetone. But when acidification method was applied, they showed significant difference of 8%. It can be concluded that DMF can extract chlorophylls more effectively without grinding and it can be a better alternative for the standard extraction solvent.

• Korean Journal of Environmental Biology
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• v.21 no.4
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• pp.422-427
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• 2003

The spatio-temporal distribution of four coexisting acartiid species in two subgenera Acartiura (Acartia hongi and A. omorii) and Odontacartia (A. erythraea and A. pacifica) was examined at seven stations in the southwestern waters of Korea, between January to December 1998. A. hongi occurred dominantly in the northern regions from winter to spring while A. omorii predominated in the southern regions in spring and early summer when the more saline (> 33.0 psu) and high chlorophyll-$\alpha$ concentration water mass appeared. With the increase of temperature (> $20^{\circ}C$), however, both species disappeared and then replaced with A. erythraea and A. pacifica. A. erythraea (rare species), appeared in the middle regions where the high chlorophyll-$\alpha$ concentration ($3{\mu}g\; I^{-1}$) in the summer, while A. pacifica was abundant in all regions through summer and fall. It is suggested that the seasonal succession of the genus Acartia was subgenus-specifically affected by environmental factors such as temperature, salinity and chlorophyll-$\alpha$ concentration.

• Korean Journal of Ecology and Environment
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• v.41 no.4
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• pp.472-484
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• 2008

The calibrated Andong Reservoir hydro-dynamic module (PART I) of the 2-dimensional hydrodynamic and water quality model, CE-QUAL-W2 [v3.2], was applied to examine the dynamics of total phosphorus, and chlorophyll $\alpha$ concentration within Andong Reservoir. The modeling effort was supported with the data collected in the field for a five year period. In general, the model achieved a good accuracy throughout the calibration period for both chlorophyll ${\alpha}$ and total phosphorus concentration. The greatest deviation in algal concentration occurred on $10^{th}$ October, starting at the layer just beneath the surface layer and extending up to the depth of 35 m. This deviation is principally attributed to the effect of temperature on the algal growth rate. Also, on the same date, the model over-predicts hypolimnion and epilimnion total phosphorus concentration but under-predicts the high concentrated plume in the metalimnion. The large amount of upwelling of finer suspended solid particles, and re-suspension of the sediments laden with phosphorus, are thought to have caused high concentration in the epilimnion and hypolimnion, respectively. Nevertheless, the model well reproduced the seasonal dynamics of both chlorophyll a and total phosphorus concentration. Also, the model tracked the interflow of high phosphorus concentration plume brought by the turbid discharge during the Asian summer monsoon season. Two different hypothetical discharge scenarios (discharge from epilimnetic, and hypolimnetic layers) were analyzed to understand the response of total phosphorus interflow plume on the basis of differential discharge gate location. The simulated results showed that the hypolimnetic discharge gate operation ($103{\sim}113\;m$) was the most effective reservoir structural control method in quickly discharging the total phosphorus plume (decrease of in-reservoir concentration by 219% than present level).

• Applied Biological Chemistry
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• v.39 no.4
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• pp.293-296
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• 1996

The present study was carried out to investigate the effect of Ni on germination, cell elongation, ${\alpha}-amylase$ activity, contents of chlorophyll and protein in radish were determined in the water culture. As the concentration of Ni was increased in the water culture, germination of radish was 55% by Ni 10 mg/kg and 30% by Ni 20 mg/kg. The ratio of cell elongation injury was 50%, by two days after Ni 20 mg/kg treatment. The injury ratio of ${\alpha}-amylase$ activity was 45% in the same condition and as the time goes on, inhibition of ${\alpha}-amylase$ activity were slightly decreased. Contents of chlorophyll a and b were decreased two days after treatment and chlorophyll a was more inhibited than chlorophyll b. Also changes of the protein contents was slightly decreased. Activity of ${\alpha}-amylase$ was decreased at germination stage, contents of chlorophyll a and b were decreased at growing stage.

• Journal of Korean Society on Water Environment
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• v.21 no.4
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• pp.360-367
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• 2005

We have performed to analyze the trophic state resulting of Lake Yongdam as a result of water quality and nutrient concentration. Lake Yongdam is artifitial multi-purpose Dam resulting from the floods of 2001. The water quality of Lake Yongdam may affect the status of the Geum river basin including the Daecheong reservoir. It is necessary to understand the trophic state to assess water quality until stability after flooding. Water quality was surveyed using depth and hydraulic condition analysis. Further density flow was estimated for stratification and trophic state of Lake Yongdam by chlorophyll ${\alpha}$ concentration (2001~2004). And Environmental factors on chlorophyll ${\alpha}$ concentration were analyzed statistically. Trophic state was evaluated as the oligotrophic state at the main stream of the reservoir and eutrophic state at the upper stream in 2001, but evaluated as eutrophic state in 2002 and 2003 by TSI of Aizaki. From the results of multiple regression analysis using stepwise method, chlorophyll ${\alpha}$ concentration was shown to be very significant when nutrient concentration is high upon initial filling of the Dam. Chlorophyll ${\alpha}$ concentration varied according to sample site, season and year. Concentration were high in the upper stream of Lake Yongdam 4, algae bloom in these watershed were affected by location and high nutrient levels in the summer season which have in turn increased phytoplankton bloom into the reservoir.

• Journal of Microbiology
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• v.45 no.2
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• pp.98-104
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• 2007

Chlorophyll ${\alpha}$ concentration and cyanobacterial cell density are regularly employed as dual criteria for determinations of the alert level for cyanobacterial bloom. However, chlorophyll ${\alpha}$ is not confined only to the cyanobacteria, but is found universally in eukaryotic algae. Furthermore, the determination of cyanobacterial cell counts is notoriously difficult, and is unduly dependent on individual variation and trained skill. A cyanobacteria-specific parameter other than the cell count or chlorophyll ${\alpha}$ concentration is, accordingly, required in order to improve the present cyanobacterial bloom alert system. Phycocyanin has been shown to exhibit a strong correlation with a variety of bloom-related factors. This may allow for the current alert system criteria to be replaced by a three-stage alert system based on phycocyanin concentrations of 0.1, 30, and $700\;{\mu}g/L$. This would also be advantageous in that it would become far more simple to conduct measurements without the need for expensive equipment, thereby enabling the monitoring of entire lakes more precisely and frequently. Thus, an alert system with superior predictive ability based on highthroughput phycocyanin measurements appears feasible.