• Ocean and Polar Research
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• v.35 no.2
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• pp.147-155
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• 2013

The purpose of this study is to investigate seasonal difference in linear trends in satellite-derived chlorophyll-a concentration (Chl-a) and their related environmental changes in the South Sea of Korea (SSK) and East China Sea (ECS) for recent 15 years (Jan. 1998~Dec. 2012) by analyzing climatological data of Chl-a, Rrs(555), sea surface wind (SSW) and nutrient. A linear trend analysis of Chl-a data reveals that, during recent 15 years, the spring bloom was enhanced in most of the ECS, while summer and fall blooms were weakened. The increased spring (Mar. - May) Chl-a was associated with strengthened winter (Dec. - Feb.) wind that probably provided more nutrient into the upper ocean from the deep. The causes of decreased summer (Jun. - Aug.) Chl-a in the northern ECS were uncertain, but seemed to be related with the nutrient limitation. Recently (after 2006), low-salinity Changjiang diluted water in the south of Jeju and the SSK had lower phosphate that caused increase in N/P ratio with Chl-a decrease. The decreased fall (Sep. - Nov.) Chl-a was associated with weakened wind that tends to entrain less nutrient into the upper ocean from the deep. This study suggests that phytoplankton in the ECS differently changes in response to environmental changes depending on season and region.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.555-560
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• 2009

To identify the food characteristics of seven melania snail species in Korea, the detailed proximate, fatty/amino acid, mineral composition and chlorophyll contents were investigated. The content ranges of moisture, crude protein, crude lipid and ash were 70.1-81.0%, 11.6-16.9%, 0.4-1.6% and 1.9-3.4%, respectively. K. nadifila showed the significant mineral contents Fe, P, Ca than other species. Total Chlorophyll level was highest in K. globus ovalis ($1.2\pm0.2$ mg/g). The major fatty acids were 16:0, 22:1, 20:1, 18:1, 20:5 and 22:6 were identified as small amounts (1.0-3.3%) of total fatty acids. Citrulline was shown to be the major free amino acids (20.4-53.1%).

• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.282-286
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• 2002

Seasonal succession of algae and water quality parameters were studied in artificial reservoirs in Daegu city from 2000 to 2001. The algal succession was evaluated with respect to dom-inant class and their frequencies. Succession order of algae in two reservoirs was : Bacillariophyceae longrightarrow Chlo-rophyceae longrightarrow Cyanobacteria longrightarrow Bacillariophyceae longrightarrow Bacillariophyceae longrightarrow Cyanobacteria longrightarrow Cyanobacteria longrightarrow Cyanobacteria. This succession order was different from other studies. The local environment condition maybe affects the succession of algae in these reservoirs. As result of correlation analysis between algal biom-ass and water quality parameters, we got low correlation coefficients. Also we got low correlation coefficients between chlorophyll-a and algal biomass. Between chlorophyll-a and water quality parameters, we got high correlation coefficients. An approach having attention to cell biovolume rather than cell number is made to understand the algal community and the ecosystem of reservoir.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.2
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• pp.176-185
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• 1998

For the sustainable production of cultured arkshell Scapharca broughtonii and pre-estimation of the harvest of it, we investigated the relationship between the habitat environmental factors and the physiological conditions of the arkshell in the two experiment sites near the Chinhae Bay, Korea. For the analysis of habitat environmental factors such as temperature, salinity, dissolved oxygen, DIP (dissolved inorganic phosphate), DIN (dissolved inorganic nitrogen), suspended solids and chlorophyll a of bottom water and T-S (total sulfide) and COD (chemical oxygen demand) of surface sediment were measured, To determine physiolosical condition of cultured arkshell, shell length, fatness, glycogen, hemoglobin content and gametogenesis were examined. Water temperature were higher in Woongchon than in Songdo in 1992, and were Higher in Songdo in 1993. Salinity were higher in Songdo than in Woongchon except from January to May in 1992. COD, suspended solids and chlorophyll a content were higher in Songdo than in Woongchon, while the contents of sediment sulfide, DO, DIP and DIN were higher in Woongchon. Based on the environmental assessment, significant factors affecting the growth and physiological condition of arkshell were quantity of food and total sulfide content in the bottom sediment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.2
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• pp.201-215
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• 2013

The characteristics of the oceanographic environment in the Aleutian Basin of the Bering Sea during spring in 1996, 1997, and 1999 were clarified. An investigation of the water properties revealed five basic layers in the Bering Sea during spring: (1) a surface layer of warm and low-salinity water induced by solar heating, (2) a subsurface layer of cold and low-salinity water propagated slowly by heat from the surface layer, (3) a thermocline layer where salinity was constant but temperature sharply decreased, (4) a temperature inversion layer, and (5) a deep layer with a gradual decrease in temperature and increase in salinity toward the bottom. The ranges of water temperature and salinity were $1.8-5.5^{\circ}C$ and 31.81-34.08 in 1996, $1.5-7.2^{\circ}C$ and 31.9-34.06 in 1997, and $0.5-5.6^{\circ}C$ and 32.0-34.11 in 1999, respectively. The water temperature of the surface layer was approximately $1.6^{\circ}C$ higher in 1997 than in 1996 and 1999. The lowest temperature at a depth of 100-150 m was about $1^{\circ}C$ lower in 1999 than in 1996 and 1997. Nutrient levels (nitrate, phosphate, and silicate) contributing to the control of the growth of phytoplankton were higher in the Aleutian Basin than in the eastern continental shelf and Bogoslof Island area. This was closely associated with the phytoplankton distribution. Nutrient concentrations were lowest at a depth of 25 m. The high primary production at that depth was confirmed from the vertical distribution of chlorophyll a. Chlorophyll a levels were above $4.0{\mu}L^{-1}$ in some areas in 1996 and 1999, but below $2.0{\mu}L^{-1}$ in most areas in 1997. Zooplankton density was about three times higher in 1999 than in 1997.

• Proceedings of the KSRS Conference
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• v.1
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• pp.122-125
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• 2006

The distribution of phytoplankton pigments were studied bimonthly at four stations from the mouth of Mahanadi River at Paradip to the 36.7km off coast in Bay of Bengal during April 2001 to December 2002. Bottom depth was shallower than 40m in all stations. The pigment concentration of Chl-a was measured. It increased from surface to bottom in the water column. The water column integrated chlorophyll-a concentration (Chl-a) varied between 6.1 and $48.5mg{\cdot}m-^2$ with peaks during monsoon period (Aug & Oct). Spatial distribution of salinity depended strongly on freshwater runoff. The salinity was 5psu at river mouth and 25.15psu at offshore in monsoon period; however it was 30psu at the river mouth in summer. We found a linear relationship between the amount of river discharge and integrated Chl-a in coastal region from 2 years observations. Extending this result, we analyzed rainfall and coastal Chl-a using satellite data. The relationship between the river discharge and monthly accumulated rainfall estimated from TRMM and others data sources was analyzed in 2001 and 2002 using Giovanni infrastructure provided by NASA. The result depended on the specified area on TRMM images; the river delta area had sharper relationship than wider rain catchments area. Moreover, the relationship between monthly averaged Chl-a derived from SeaWiFS and monthly accumulated rainfall estimated from TRMM was analyzed from 1998 to 2005. It was clear that the broom in monsoon period was strongly controlled by rainfall on river delta.

• Journal of Korean Society on Water Environment
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• v.33 no.2
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• pp.219-229
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• 2017

A watershed-river linked modeling system was developed to forecast the water quality, particularly weekly changes in chlorophyll-a concentration, of the Yeongsan River, Korea. Hydrological Simulation Program-Fortran (HSPF) and Environmental Fluid Dynamics Code (EFDC) were adopted as the basic model framework. In this study, the EFDC model was modified to effectively simulate the operational condition and flow of multi-functional weirs constructed in the main channel of rivers. The model was tested against hydrologic, water quality and algal data collected at the right upstream sites of two weirs in 2014. The mean absolute errors (MAEs) of the model calibration on the annual variations of river stage, TN, TP, and algal concentration are 0.03 ~ 0.10 m, 0.65 ~ 0.67 mg/L, 0.03 ~ 0.04 mg/L, and $9.7{\sim}10.8mg/m^3$, respectively. On the other hand, the MAE values of forecasting results for chlorophyll-a level at the same sites in 2015 range from 18.7 to $22.4mg/m^3$, which are higher than those of model calibration. The increased errors in forecasting are mainly attributed to the higher uncertainties of weather forecasting data compared to the observed data used in model calibration.

• Journal of Plant Biology
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• v.31 no.4
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• pp.299-307
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• 1988

The electron transport activities of choloroplasts isolated from hte detached rise (Oryza sativa L. cv. Chucheong) leave stored under low temperature(4$^{\circ}C$) with light illumination were investigated to understand the role of light in the low temperature inhibition of photosynthesis in the chilling-sensitive plants. Chlorophyll content of the detached leaves upon incubation at 28$^{\circ}C$ and 4$^{\circ}C$ in the dark was also measured. The rice seedlings were grown with Hoagland medium in the growth chamber of 28$^{\circ}C$ temperature and 400 ft.c fluorescent light with the photoperiod of 16 h. Although chlorophyll content of the detached leaves stored in the dark declined by 61.7% after 28$^{\circ}C$ treatement, there occurred only 5.2% decrease of chlorophyll with 4$^{\circ}C$ treatment. Low temperature treatment(4$^{\circ}C$) for 6 days brought about decreases in total photosystem(PS II＋PS I) activities by 35.2% and 73.6% in te presence and absence of light, respectively, while after 28$^{\circ}C$ treatment of the detached leaves for 6 days in the dark there was only 27.6% decrease in PS II＋PS I activity. PS II activities were also decreased by 35.6% and 72.2% in the light and dark, respectively. PS I activities were decreased slightly, however, by 7.6% and 16.2% in the light and dark, respectively. Investigations into DPClongrightarrowDCPIP and NH2OHlongrightarrowDCPIP activities revealed that low temperature inhibition of PS II activities was not due to the inactivation of the water oxidation capacity at low temperature. It was concluded that light protects the electron transport activities of isolated rice chloroplasts from the inhibitory effect of low temperature in the detached leaves.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.122-128
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• 1998

Characteristic changes in chlorophyll fluorescence from thalli of red alga, Porphyra, under high salt stress and during subsequent recovery were investigated, and the differences in the sensitivity to the stress among four species of Porphyra with different intertidal distributions were compared. By the treatment of NaCl with $9\%$ or higher concentrations, photochemical efficiency (Fv/Fm) decreased in a biphasic pattern: a rapid decrease was observed within 1­3 h and followed by a slow decline. The decrease of Fv/Fm was mainly due to the increase of Fo without significant increases of Fm. When the thalli treated with $15\%$ NaCl for 6 h were returned to natural sea water for recovery, the increase of Fv/Fm also showed a biphasic pattern: a rapid increase of Fv/Fm was observed within 2 h and followed by a slow increase. Differences in the sensitivity to salt stress among the four species could be found during recovery after the treatment of severe salt stress. After the treatment of $20\%$ NaCl for 6 h, Fv/Fm decreased below 0.3 in all of the four Porphyra species, and the species living in upper parts of the intertidal zone (P. suborbiculata and P. pseudolinearis) could recover better compared with the species in lower parts of the intertidal zone (P. seriata and P. yezoensis), during recovery for 24 h. The species collected from the coast of the South Sea seemed to be more tolerant than those in the East Sea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.1
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• pp.31-36
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• 1975

A combination of two specifically different pigments, phycoerythrine and chlorophyll, gives the laver shining black color. This shining black color is the dominant factor in deciding tile quality of the dried product of laver (dried laver). Therefore, this experiment was carried out to know the effect of tannic acid as a pigment fixing agent. Raw laver, Porphyra spp., was treated with tannic acid solutions to prevent dissolution of biliproteins especially phycoerythrine in to the fresh water. This danger is mostly revealed when the chopped and shredded lavers are suspended in fresh water before the laver sheets are finally made. The influence of mechanical damage with different diameters of chopper plate on dissolution of the pigment was also mentioned. Theresultsobtainedareasfollows: 1. When the raw laver not yet chopped was stored for 3 days at $1\~5^{\circ}C$ in a dark place, the contents of chlorophyll and phycoerythrine decreased. 2. In the organoleptic test (Table 2,3,4),: the dried laver with a good coloration and surface gloss was obtained from a chopper plate with 7 mm or 3 mm. 3. A tannic acid solution of $0.02\%$ and $0.004\%$ appeared effective In preventing dissolution of phycoerythrine.