• Title/Summary/Keyword: algal bloom

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The exceptionally large genome of the harmful red tide dinoflagellate Cochlodinium polykrikoides Margalef (Dinophyceae): determination by flow cytometry

  • Hong, Hyun-Hee;Lee, Hyun-Gwan;Jo, Jihoon;Kim, Hye Mi;Kim, Su-Man;Park, Jae Yeon;Jeon, Chang Bum;Kang, Hyung-Sik;Park, Myung Gil;Park, Chungoo;Kim, Kwang Young
    • ALGAE
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    • v.31 no.4
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    • pp.373-378
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    • 2016
  • Cochlodinium polykrikoides is a red-tide forming dinoflagellate that causes significant worldwide impacts on aquaculture industries and the marine ecosystem. There have been extensive studies on managing and preventing C. polykrikoides blooms, but it has been difficult to identify an effective method to control the bloom development. There is also limited genome information on the molecular mechanisms involved in its various ecophysiology and metabolism processes. Thus, comprehensive genome information is required to better understand harmful algal blooms caused by C. polykrikoides. We estimated the C. polykrikoides genome size using flow cytometry, with detection of the fluorescence of DNA stained with propidium iodide (PI). The nuclear genome size of C. polykrikoides was 100.97 Gb, as calculated by comparing its mean fluorescence intensity (MFI) to the MFI of Mus musculus, which is 2.8 Gb. The exceptionally large genome size of C. polykrikoides might indicate its complex physiological and metabolic characteristics. Our optimized protocol for estimating the nuclear genome size of a dinoflagellate using flow cytometry with PI can be applied in studies of other marine organisms.

Seasonal Variations of Size-structured Phytoplankton in the Chunggye Bay (청계만 식물플랑크톤 크기구조의 계절적 변동)

  • Ji, Sung;Sin, Yong-Sik;Soh, Ho-Young
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.13 no.4
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    • pp.333-341
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    • 2008
  • Three embankments are located in the Chunggye Bay, each named as Changpo, Bokkil and Kuil and environmental changes are expected due to freshwater input. To investigate this phenomenon, three sample sites in front of each embankment gate were selected in Nov. 2006(autumn), Feb. 2007(winter), May. 2007(spring) and Aug. 2007(summer). At every point of embankment spot, large cells(micro-size, >$20\;{\mu}m$) of phytoplankton were turned out to be a major cause of algal bloom in Feb. 2007 and nano-size($2-20\;{\mu}m$) phytoplankton became dominant during rainy season. In rainy season, each point of embankment showed low salinity and transparency with higher ammonium and phosphorus concentrations than dry season. However, the number of phytoplankton has decreased and it is expected that freshwater influx has more influence on high turbidity and radical decrease of salinity than nutrient. According to the results of this study, therefore, nutrient could have more influence on growth of phytoplankton in dry season, but high turbidity and radical changes of salinity have more influence in rainy season.

A Study on Comparison of Phycocyanin Extraction Methods for Hyperspectral Remote Sensing of Cyanobacteria in Turbid Inland Waters (국내 담수역 남조류 원격탐사를 위한 피코시아닌 추출법 비교 연구)

  • Ha, Rim;Shin, Hyunjoo;Nam, Gibeom;Park, Sanghyun;Kang, Taegu;Song, Hyunoh;Lee, Hyuk
    • Journal of Korean Society on Water Environment
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    • v.32 no.6
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    • pp.520-527
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    • 2016
  • Phycocyanin (PC) is one of the water-soluble accessory pigments of cyanobacteria species, and its concentration is used to estimate the presence and relative abundance of cyanobacteria. In laboratory experiments, PC content of field data were determined using Sarada's freeze-thaw method in algal bloom season. The effectiveness of three selected extraction methods (repeated freeze-thaw method, homogenization, power control) for PC were determined. The extraction efficiency of phycocyanin was the highest (of the methods compared) when a single freezing-thawing cycle was followed by pre-sonication. Applying this optimized method to surface water of Korean inland waters, the average concentration distribution was estimated at $2.9{\sim}51.9mg/m^3$. It has been shown that the optimized pre-sonication method is suitable to measure cyanobacteria PC content for the characterization of inland waters. The approach and results of this study indicates the potential of effective methods for remote monitoring and management of water quality in turbid inland waters using hyperspectral remote sensing.

New Algicidal Compounds from a Marine Algicidal Bacterium against Cochlodinium polykrikoides

  • Jeong, Seong-Yun;Kim, Min-Ju;Lee, Sang-Youb;Son, Hong-Joo;Lee, Sang-Joon
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • 2006.11a
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    • pp.285-289
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    • 2006
  • In screening of algicidal bacteria, we isolated a marine bacterium which had potent algicidal effects on harmful algal bloom (HAB) species. This organism was identified as a strain very close to Bacillus subtilisby 16S rRNA gene sequencing. This bacterium, Bacillus sp. SY-1, produces very active algicidal compounds against the harmful dinoflagellate Cochlodinium polykrikoides. We isolated three algicidal compounds (MS 1056, 1070, 1084) and identified them by amino acid analyses, fast atom bombardment mass spectrometry (FAB-MS), infrared spectroscopy (IR), $^1H$, $^{13}C$, and extensive two-dimensional nuclear magnetic resonance (2D NMR) techniques including $^1H-^{15}N$ HMBC analysis. One of them, MS 1056, contains a b-amino acid residue with an alkyl side chain of $C_{15}$. MS 1056, 1070, and 1084 showed algicidal activities against C. polykrikoides with an $LC_{50}$ (6 hrs) of 2.3, 0.8, $0.6\;{\mu}g/ml$, respectively. These compounds also showed significant algicidal activities against other harmful dinoflagellates and raphidophytes. In contrast, MS 1084 showed no significant growth inhibition against various organisms coexisting with HAB species in natural environments, including bacteria, eukaryotic microalgae, and cyanobacteria, although it inhibited growth of some fungi and yeasts. These observations imply that algicidal bacterium Bacillus sp. SY-1 and its algicidal compounds could play an important role in regulating the onset and development of HABs in the natural environments.

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A Prelimiary Study for Marine Ecosystem Health Assessment Using the Planktonic Organism in Jinhae Bay (진해만에서 부유생물을 이용한 해양생태계 건강성평가 예비조사)

  • Baek, Seung-Ho;Choi, Hyun-Woo;Kim, Young-Ok
    • Korean Journal of Environmental Biology
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    • v.28 no.3
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    • pp.125-132
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    • 2010
  • In order to assess the effect of pollution on marine ecosystem, we examined the plankton health assessment at 16 stations during summer season in Jinhae Bay. The organic and inorganic pollutant sources (dissolved organic carbon; DOC, chemical oxygen demand; COD and Chlorophyll a; Chl.a), including planktonic orangism such as enterobacteria Escherichia coli, heterotrophic bacteria (HB), autotrophic nano-flagellates (ANF), heterotrophic nano flagellates (HNF), ciliate and harmful algal bloom species (HABs) were used to characterize marine ecosystem health assessment. Of these, we tentatively selected those items Chl.a, HABs, HB and E. coli for plankton health index (PHI). Also, the scoring criteria for each metric were based on a statistical analysis and then, the grades are rated on four levels. As a result, the ecological assessment of these data reveals that PHI in Jinhae Bay is rated as "Good or fair" for overall conditions. The present study suggests that the PHI might be considered as one of important management tool to assess marine ecosystem health of Jinhae Bay.

A Study on Spatial and Temporal Patterns of Water Quality in the Middle Area of the Nakdong River, Korea (낙동강 중류 보 구간에서의 시 · 공간적 수질 분포 특성 연구)

  • Na, Eun Hye;Park, Suyoung;Kim, Jongha;Im, Seongsoo;Kim, Kyunghyun
    • Journal of Korean Society on Water Environment
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    • v.31 no.6
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    • pp.723-731
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    • 2015
  • We investigated the spatial and temporal patterns of water quality in the Gangjung-Goryoung weir that is located in the middle area of the Nakdong river, Korea. The monitoring results indicated that there are discernible vertical differences in water quality during the pre- and post-monsoon periods (May to September). During this period, it was observed that the weak thermal stratification formed at the maximum level, and pH, Chl-a, and DO concentrations in the surface layer were higher than those in the bottom layer. This vertical difference was especially noticeable for DO concentrations: there were DO depletions at the bottom layer in late June to early August. During the summer monsoon period with heavy rainfall, there was a decline in vertical differences in water quality. From this study, it was suggested that continuous monitoring of vertical profiles could become a useful tool for identifying the spatial and temporal distributions of water quality and for developing the best management policy for water quality in the Nakdong river.

Characterization of a Novel Alga-Lytic Bacterium, Acidovorax temperans AK-05, Isolated from an Eutrophic Lake for Degradation of Anabaena cylindrica (부영양 호수에서 분리한 Acidovorax temperans AK-05의 Anabaena cylindrica 분해 특성)

  • Kim, Jeong-Dong;Han, Myung-Soo
    • Korean Journal of Ecology and Environment
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    • v.37 no.2 s.107
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    • pp.241-247
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    • 2004
  • Isolation and identification of alga-lytic bacteria were carried out. Fifteen isolates of alga-lytic bacteria were screened by the double layer method using A. cylindrica NIES-19 as a sole nutrient and four isolates among them were compared with their alga-lytic activity. The isolate AK-05 exhibiting the highest alga-lytic activity was identified as Acidovorax temperans base on its 16S rDNA sequence. The culture supernatant of the isolate AK-05 was reliable for the alga-lytic. Alga-lytic activity assays of culture supernatant revealed that the major substances for alga-lytic activity were non-proteins and heat stable. The highest alga-Iytic activity was practical under alkaline conditions and at 25${\sim}$$30^{\circ}C$. It is indicating an advantage for the application of water blooms by cyanobacteria in eutrophic lakes where the pH is generally in alkaline region.

Response of Growth and Toxigenicity to Varying Temperature and Nutrient Conditions in Aphanizomenon flos-aquae (Cyanophyceae) (환경조건에 따른 Aphanizomenon flos-aquae (Cyanophyceae) 균주의 성장 반응 및 독소 생성)

  • Ryu, Hui-Seong;Shin, Ra-Young;Lee, Jung-Ho
    • Journal of Korean Society on Water Environment
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    • v.33 no.5
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    • pp.538-545
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    • 2017
  • The purpose of this study is to investigate growth response and toxigenicity under various temperature and nutritional conditions, in order to understand the physioecological characteristics of Aphanizomenon flos-aquae, which is a bloom-forming cyanobacterium in the Nakdong River. The strain was inoculated into media under combinations of four temperatures (4, 12, 21, $30^{\circ}C$) and three nutrients (modified CB medium, P-depleted CB medium, N-depleted CB medium) for 28 days. The algae-inhibition tests were performed to assess the potential allelopathic effects of the strains' filtrates on the growth of four algae strains (Microcystis aeruginosa, Aulacoseria ambigua f. spiralis, Aphanizomenon flos-aquae, Scenedesmus obliquus). Toxin production of a strain was measured by Enzyme-Linked ImmunoSolbent Assay (ELISA). The optimal growth temperature (Topt) of strains was $19.9^{\circ}C$ ($18.3-21.2^{\circ}C$), and the temperature range for growth was from $-0.3^{\circ}C$ to $34.3^{\circ}C$. Specific growth rate (${\mu}$) in modified CB medium varied from 0.10 to $0.16day^{-1}$, and the maximum growth rate (${\mu}_{max}$) was $0.17day^{-1}$. Although growth curves under N-existed and N-depleted conditions were almost the same, growth under N-depleted condition was relatively slowed (${\mu}=0.09$ to $0.14day^{-1}$), with a decreased maximum cell density. However, growth under the P-depleted condition was restricted for all temperatures, Two stains of Aphanizomenon flos-aquae were confirmed as not producing toxins, because saxitoxin and cylindrospermopsin were not detected by ELISA. The exudates or filtrates from the Aphanizomenon flos-aquae (DGUC003) resulted in significant inhibition of algal growth on the Aulacoseira ambigua f. spiralis (DGUD001) and Aphanizomenon flos-aquae (DGUC001) (p < 0.01).

Evalution of Three Species of Haptophyte Algae for the Culture of the Marine Copepod Tigriopus japonicus (해산 요각류 Tigriopus japonicus 개체군 성장에 미치는 착편모조의 영향)

  • Kim, Hyeung-Sin;Jung, Min-Min
    • Journal of Aquaculture
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    • v.18 no.2
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    • pp.86-91
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    • 2005
  • Three haptophyte algae, Isochrysis galbana, Prymnesium parvum and P. patelliferum were offered to the marine copepod Tigriopus japonicus as food. Growth rate of larvae, egg production, mortality and comsumption rates of T. japonicus were measured for each of the haptophyte species offered. The growth rate of larvae, egg production and algal ingestion of T. japonicus fed on P. parvum and P. patelliferum were much lower than those fed on I. galbana and corresponding high mortality rates were also observed during the experimental period. The harmful effects observed during the present study indicate that bloom-forming haptophyte algae, P. parvum and P. patelliferum are not suitable feed species for culture of copepod, T. japonicus.

Changed Aquatic Environment Due to An Estuary Dam: Similarities and Differences Between Upstream and Downstream (금강하구언 조성으로 인한 환경변화: 호수측과 하구측 비교)

  • Yang, Jae Sam
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.17 no.1
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    • pp.52-62
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    • 2014
  • As a case study of the changed aquatic environment due to an estuary dam, the Geum River Estuary Dam System (GREDS) has been investigated for the last two decades. We sought the similarities and differences in the disrupted aquatic environment between the estuarine and lacustrine sides of the GREDS. Both sides of the GREDS shared similar aquatic disruptions, such as elongated hydraulic residence times, deteriorated water quality, highly accumulated organic-rich sediments, and considerable siltation of river-transported materials prior to reaching coastal waters. The disruptions of water quality such as high nutrients concentration and frequent bloom of blue-green algal are much more noticeable in the reservoir than in the estuary. However serious siltation problem has been reported from the estuary, which will possibly threaten the proper functioning of the natural Kunsan Estuarine System.