• Title, Summary, Keyword: Phytoplankton maximum region

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The numerical simulation on variation of phytoplankton maximum region in the estuary of Nakdong river -I. The state of variation of phytoplankton maximum region- (낙동강 하구해역의 식물플랑크톤 극대역 변동에 관한 수직시뮬레이션 -I. 식물플랑크톤 극대역 변동 현황-)

  • 이대인
    • Journal of Environmental Science International
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    • v.9 no.5
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    • pp.369-374
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    • 2000
  • The estuary of Nakdong river is very influenced by the freshwater contained nutrients and organic materials. The response results of these influences are eutrophication and red tide outbreak in this region. Concentration of chlorophyll a was 0.78~62.55$\mu\textrm{g}$/L in February 1.20~21.29$\mu\textrm{g}$/L in April 1.88~188.35$\mu\textrm{g}$/L in June and 0.78~11.21$\mu\textrm{g}$/L in August respectively. The decrease of chlorophyll a is considered that residence time is shorten by increase of freshwater discharge and unfavorable growth condition of phytoplankton is created by diffusion of low salinity and increase of turbidity. The phytoplankton maximum region located inner side of this estuary during winter season whereas it was moved to outer side when mean discharge of the Nakdong risver was increased, Therefore the variation of phytoplankton maximum region was affected by input discharge from the Nakdong river basin.

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The numerical simulation on variation of phytoplankton maximum region in the estuary of Nakdong river -II. The numerical simulation on variation of phytoplankton maximum region- (낙동강 하구지역의 식물플랑크톤 극대역 변동에 관한 수직시뮬레이션 -II. 식물플랑크톤 극대역 변동의 수치시뮬레이션-)

  • 이대인
    • Journal of Environmental Science International
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    • v.9 no.5
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    • pp.375-384
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    • 2000
  • It is very important to interprete and simulate the variation of phytoplankton maximum region for the prediction and control of red tide. This study was composed of two parts first the hydrodynamic simulation such as residual current and salinity diffusion and second the ecological simulation such as phytoplankton distribution according to freshwater discharge and pollutant loads. Without the Nakdong river discharge residual current was stagnated in inner side of this estuary and surface distribution of salinity was over 25psu. On the contrary with summer mean discharge freshwater stretched very far outward and some waters flowed into Chinhae Bay through the Kadok channel and low salinity extended over coastal sea and salinity front occurred. From the result of contributed physical process to phytioplankton biomass the accumulation was occurred at the west part of this estuary and the Kadok channel with the Nakdong river discharge. When more increased input discharge the accumulation band was transported to outer side of this estuary. The frequently outbreak of red tide in this area is caused by accumulation of physical processes. The phytoplankton maximum region located inner side of this estuary without the Nakdong river discharge and with mean discharge of winter but it was moved to outer side when mean discharge of the Nakdong river was increased. The variation of input concentration from the land loads was not largely influenced on phytoplankton biomass and location of maximum region. When discharge was increased phytoplankton maximum region was transferred to inner side of the Kadok channel. ON the other hand when discharge was decreased phytoplankton maximum region was transferred to inner side of this estuary and chlorophyll a contents increased to over 20$\mu\textrm{g}$/L Therefore if any other conditions are favorable for growth of phytoplankton. decreas of discharge causes to increase of possibility of red tide outbreak.

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Phytohydrography and the Vertical Pattern of Nitracline in the Southern Waters of the Korean East Sea in Early Spring (춘계 한국 동해 남부해역에서의 식물 수문학적 수역과 질산염약층의 수직양상)

  • Shim, Jae Hyung;Yang, Sung Ryull;Lee, Won Ho
    • 한국해양학회지
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    • v.24 no.1
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    • pp.15-28
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    • 1989
  • A study on quantitative phytoplankton samples, hydrographic conditions (temperature, salinity, dissolved oxygen), and nutrients has been performed in the southern waters of the Korean East Sea in early spring. Phytoplankton community showed close correlation with hydrographic conditions. This study area could be divided into three phytohydrographic regions; 1) East Korean Warm Water Region (a branch of Tsushima Current), 2) North Korean Cold Water Region, and 3) offshore water region not affected by other two water regions. Vertical distribution of phytoplankton is dependent upon stability of water column and nutrient concentration. Nutrient concentration shows characteristic distribution according to water masses. N/P ratio of ca. 3 in surface layer indicates that nitrogen is the major limiting nutrient in this area. N/P removal ratio was 12.54 ($r^2$ = 0.96), consistent with the Redified ratio. Primary nitrite maxima at the nitracline depths are thought to be formed by phytoplankton exudation. Secondary nitrite maximum was observed in coastal area with dissolved oxygen content of >5.2 ml/l much higher than <0.25 ml/l in other areas. The mechanism of secondary maximum is different from that of other regions, and whether it may be due to in situ degradation of organic matter by bacterial activity is still open to discuss.

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Spatial and Temporal Variations of Environmental Factors and Phytoplankton Community in Andong Reservoir, Korea (안동호에서 환경요인과 식물플랑크톤의 시.공간적 변동)

  • Park, Jae-Chung;Park, Jung-Won;Kim, Jong-Dal;Shin, Jae-Ki
    • ALGAE
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    • v.20 no.4
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    • pp.333-343
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    • 2005
  • Spatial and temporal variations of environmental factors and phytoplankton community were investigated in the three stations of Andong Reservoir in 1997 and 2003. The changes of physico-chemical water quality and phytoplanktonic biomass were higher in 2003 than that of 1997, due to rainfall difference. The concentration of total nitrogen (TN) and total phosphorus (TP) in the reservoir decreased, but total nitrogen fell relatively more between them. TN/TP ratio decreased from 109 to 90 showing no change at the downstream but a big decrease at the midand upstream. Predominant phylum of phytoplankton in Andong Reservoir were six genus that composed to Anabaena, Aphanizomenon and Microcystis of Cyanophyceae, Cosmarium and Scenedesmus of Chlorophyceae and Synedra of Bacillariophyceae, respectively. Among the observed phytoplankton, diatom Synedra occured as the maximum amount of 3,400 cells mL$^{-1}$ even at the above 30°C. Green algae Scenedesmus observed along with Microcystis. It seemed to be compete with Microcystis during the high water temperature period. Although trophic state of Andong Reservoir was decreased, the standing crops of phytoplankton were increased. Moreover bluegreen algae, Aphanizomenon and Microcystis in the region of upstream to midstream and diatom, Synedra in the region of midstream to downstream were increased until to reach the algal bloom, respectively. It seemed necessary to attention the changes of blue-green algae Aphanizomenon, that has an ability of nitrogen fixation.

Relative Importance of Bottom- up vs. Top-down Controls on Size-structured Phytoplankton Dynamics in a Freshwater Ecosystem: I. Temporal and Spatial Variations of Size Structure (담수성 식물플랑크톤의 크기별 동태에 대한 상향식, 하향식 조절간의 상대적 중요도 조사: I. 크기구조의 시 ${\cdot}$ 공간적 변동)

  • Kim, Jong-Min;Sin, Yong-Sik
    • Korean Journal of Ecology and Environment
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    • v.36 no.4
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    • pp.403-412
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    • 2003
  • Temporal and spatial variations of size-structured phytoplankton (chlorophyll a) were investigated over an annual cycle (February-October, 2003) to elucidate phytoplankton dynamics in the Juam Reservoir, Chonnam. Physical properties were also measured to investigate the relationship between the properties and temporal and spatial variations of size structured phytoplankton using simple linear regression. Phytoplankton (chlorophyll a) were grouped into three size classes: micro-size(> 20 ${\mu}m$), nano-size (3-20 ${\mu}m$) and pico-size (< 3 ${\mu}m$) in this study. Physical properties included water temperature, light attenuation coefficients, PAR (photosynthetically active radiation) and turbidity. Maximum chlorophyll a was observed in April, 2003 in the lower region whereas a peak of chlorophyll a developed in October, 2003 in the upper region. Large cell-sized phytoplankton (micro-size class)were dominant in the events of the chlorophyll a peaks. Potential mechanisms in the physical properties affecting the size-structured phytoplankton dynamics in the Juam Reservoir were discussed.

Composition and Distribution of Phytoplankton with Size Fraction Results at Southwestern East/Japan Sea

  • Park, Mi-Ok
    • Ocean Science Journal
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    • v.41 no.4
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    • pp.301-313
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    • 2006
  • Abundance and distribution of phytoplankton in seawater at southwestern East/Japan Sea near Gampo were investigated by HPLC analysis of photosynthetic pigments during summer of 1999. Detected photosynthetic pigments were chlorophyll a, b, $c_{1+2}$ (Chl a, Chl b, Chl $c_{1+2}$), fucoxanthin (Fuco), prasinoxanthin (Pras), zeaxanthin (Zea), 19'-butanoyloxyfucoxanthin (But-fuco) and beta-carotene (B-Car). Major carotenoid was fucoxanthin (bacillariophyte) and minor carotenoids were Pras (prasinophyte), Zea (cyanophyte) and But-fuco (chrysophyte). Chl a concentrations were in the range of $0.16-8.3\;{\mu}g/land$ subsurface chlorophyll maxima were observed at 0-10m at inshore and 30-50 m at offshore. Thermocline and nutricline tilted to the offshore direction showed a mild upwelling condition. Results from size-fraction showed that contribution from nano+picoplankton at Chl a maximum layer was increased from 18% at inshore to 69% at offshore on average. The maximum contribution from nano+picoplankton was found as 87% at St. E4. It was noteworthy that contribution from nano+picoplanktonic crysophytes and green algae to total biomass of phytoplankton was significant at offshore. Satellite images of sea surface temperature indicated that an extensive area of the East/Japan Sea showed lower temperature ($<18\;^{\circ}C$) but the enhanced Chi a patch was confined to a narrow coastal region in summer, 1999. Exceptionally high flux of low saline water from the Korea/Tsushima Strait seemed to make upwelling weak in summer of 1999 in the study area. Results of comparisons among Chi a from SeaWiFS, HPLC and fluorometric analysis showed that presence of Chi b cause underestimation of Chi a about 30% by fluorometric analysis but overestimation by satellite data about 30-75% compared to HPLC data.

The Clarification Of Spatial-temporal Patterns of Phytoplankton From Southern Korean Coastal Waters In 2004 (2004년 한국 남해연안 해역에 출현하는 식물플랑크톤의 시.공간적 특성 조사)

  • Cho Eun-Seob;Kim Jeong-Bae;An Kyoung-Ho;Yu Jun;Kwon Jung-No;Jeong Chang-Su
    • Journal of Environmental Science International
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    • v.15 no.6
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    • pp.539-562
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    • 2006
  • The clarification of spatial-temporal patterns of phytoplankton from southern coastal waters during the period of March to November in 2004 was carried out. Total cell numbers were shown in 5,286 cells $ml^{-1}$ on March and reached to encounter a peak of 27,775 cells $ml^{-1}$ on July. Mean cell number was also shown in maximum of 1,587 cells $ml^{-1}$ on July, which recorded approximately two times higher than on June. The cell number of phytoplankton from southmiddle waters attained an abundance of ${\geq}35%$ regardless of months, which was the highest the abundance of phytoplankton in 2004 than any other waters in this study. Southwestern waters were lower the cell number of 2-5 times than those of southmiddle and southeastern waters. In particular, Prorocentrum occurred in southeastern waters on June and the highest cell number of 8,200 cells $ml^{-1}$ around Tongyeong region on July, which was recorded to occupy the value of 60.9% in southeast waters. The abundance of Skeletonema costatum as a dominant taxa in southwest was shown in ${\geq}60%$ on March, July, September, and October, whereas was also recorded to achieve the abundance of above 80% in southmiddle waters on March, July, and September. The majority of the taxa in southeastern waters was diatom: Eucampia zoodiacus, and Chaetoceros spp.. They occupied above 45%. On November, most of southern waters were abundant to Chaetoceros spp. On the basis of cluster analysis using SPSS ver 10.0, phytoplankton occurring on March showed somewhat no correlation with all of southern waters. In contrast to on March, the relationship between southwestern and southmiddle waters was shown on August and November, indicating a distinction from southeastern waters. However, the distance between southwestern/middle and southeastern waters appeared to be less than 5. Consequently, the abundance of phytoplankton in southern waters showed much fluctuations in temporal and spatial assays. In particular, southwestern and southmiddle waters during the periods of summer and winter appeared to be a similar to environmental characteristics.

Taxonomic Groups of Phytoplankton Communities after the Commencement of the Construction of a Waterproofing Dike in Saemangeum Region (새만금지역 내방수제 착공 이후 식물플랑크톤 군집의 분류군)

  • Yeo, Hwan-Goo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.1
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    • pp.895-899
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    • 2015
  • The present study examined the phytoplankton communities of 4 regions, fresh water sites, estuary, Mankyeong and Dongjin lake and offshore regions, 4 times a year from 2011 to 2013. The number of species were 48-59 in 2011 (March, June, September, and November). From Mankyeong and Dongjin lake, fresh water species were dominated in June and coexisted with seawater species in September 2011. 45-65 species were observed in 2012 (April, June, September, and November) and diverse cyanophytes were present at the fresh water sites in September. The number of species reached up to 56-69 in 2013 (March, June, September, and November). In particular, owing to the diverse dinoflagellates from seawater and various cyanophytes and chlorophytes from fresh water, the maximum species number was recorded in June, 2013.

Estimation of Sea Surface Current Vector based on Satellite Ocean Color Image around the Korean Marginal Sea

  • Kim, Eung;Ro, Young-Jae;Ahn, Yu-Hwan
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.816-819
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    • 2006
  • One of the most difficult parameters to measure in the sea is current speed and direction. Recently, efforts are being made to estimate the ocean current vectors by utilizing sequential satellite imageries. In this study, we attempted to estimated sea surface current vector (sscv) by using satellite ocean color imageries of SeaWifs around the Korean Peninsula. This ocean color image data has 1-day sampling interval and spatial resolution of 1x1 km. Maximum cross-correlation method is employed which is aimed to detect similar patterns between sequential images. The estimated current vectors are compared to the surface geostrophic current vectors obtained from altimeter of sea level height data. In utilizing the color imagery data, some limitations and drawbacks exist so that in warm water region where phytoplankton concentration is relatively lower than in cold water region, estimation of sscv is poor and unreliable. On the other hand, two current vector fields agree reasonably well in the Korean South Sea region where high concentration of chlorophyll-a and weak tide is observed. In the future, with ocean color images of shorter sampling interval by COMS satellite, the algorithm and methodology developed in the study would be useful in providing the information for the ocean current around Korean Peninsula.

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On the Marine Environment and Distribution of Phytoplankton Community in the Northern East China Sea in Early Summer 2004 (이른 여름 동중국해 북부해역의 해양환경과 식물플랑크톤 군집의 분포특성)

  • Yoon, Yang-Ho;Park, Jong-Sick;Soh, Ho-Young;Hwang, Doo-Jin
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.8 no.2
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    • pp.100-110
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    • 2005
  • We carried oui a study on the marine environment and distribution of phytoplankton community, such as chlorophyll a, species composition, dominant species and standing crops in the Northern East China Sea during early summer of 2004. According to the analysis of a T-S diagram, three characteristics of water masses were identified. We classified them into the coastal water mass, the cold water mass and the oceanic water mass. The first was characterized by the low temperature and the low salinity originated from China territory, the secondary was characterized by the low temperature, the low salinity and the high density originated from bottom cold water of Yellow Sea, and the third was done by the high temperature and salinity originated from Tsushima warm current. The internal discontinuous layer among them was farmed at the intermediate depth (about $5{\sim}30m$ layer). And the thermal front by upwelling region between the cold water mass and Tsushima warm current appeared in the central parts of the South Sea of Korea. The Phytoplankton community in the surface and stratified layers was a total of 44 species belonging to 26 genera. Dominant species were Prorocentrum triestinum, Scrippsiella trochoidea, Skeletonema costatum & Leptocylindrus mediterraneus. Standing crops of phytoplankton in the surface layer fluctuated between $0.3{\times}10^3$ cells/L and $10.8{\times}10^3$ cells/L. Diatoms appeared mainly in the Tsushima warm current regions, and flagellates occurred in the frontal zone and the low salinity regions where was the transfer areas of Chinese continental coastal waters. Chlorophyll a concentration by controlled phytoflagellate ratio in the South Sea of Korea was high values in the frontal zone and sub-surface layer. It was high concentration in the upwelling and coastal waters regions, but low concentration in the Tsushima warm current regions. The Chl-a maximum layers appeared in the thermochline depth or sub-surface layer lower than thermocline. The phytoplankton production in the South Sea of Korea was controlled by the expanded coastal waters of Chinese Continent which include a high concentrations of nutrients.

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