• Title/Summary/Keyword: Marine Algae

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Effects of Heated Effluents on the Intertidal Macroalgal Community nearWolseong, the East Coast of Korea (동해안 월성원전의 온배수 방출이 주변 해조군집에 미치는 영향)

  • Kim, Young-Hwan;Ahn, Jung-Kwan
    • ALGAE
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    • v.21 no.4
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    • pp.453-461
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    • 2006
  • This study is intended to clarify the structure and seasonal dynamics of warm tolerant benthic marine algal community in Korea. The species composition and biomass of marine algae at the discharge canal of Wolseong nuclear power plant on the East Coast of Korea were investigated seasonally from February 2001 to October 2005. As a result, 43 species (6 blue-green, 8 green, 9 brown and 20 red algae) of marine algae were found at the discharge canal during the past five years. In general, the number of species observed was abundant during winter to summer and less in autumn. Lyngbya confervoides and Enteromorpha compressa always occurred at the discharge canal during the past five years, and Oscillatoria brevis, Padina arborescens and Caulacanthus ustulatus were common species found more than 80% frequency during the study period. Seasonal fluctuations of mean biomass were 2-659 g dry wt m–2 and dominant species in biomass were Caulacanthus ustulatus (contribution to a total biomass proportion 37%), Enteromorpha compressa (26%) and Padina arborescens (24%). Results showed that, in the floristic composition, the green algae occurred as common algal group at the discharge canal of Wolseong nuclear power plant. In the quantitative aspect, however, the red algae such as Caulacanthus ustulatus and Ahnfeltiopsis flabelliformis appeared as predominant group at the discharge canal, in contrast to Kori nuclear power plant where there was a definite green algal dominance. Differences in algal communities developed at the discharge canals of three nuclear power plants on the East Coast of Korea can probably be related to local environmental factors.

Occurrence and pathogenicity of Pythium (Oomycota) on Ulva species (Chlorophyta) at different salinities

  • Herrero, Maria-Luz;Brurberg, May Bente;Ojeda, Dario I.;Roleda, Michael Y.
    • ALGAE
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    • v.35 no.1
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    • pp.79-89
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    • 2020
  • Pythium species are ubiquitous organisms known to be pathogens to terrestrial plants and marine algae. While several Pythium species (hereafter, Pythium) are described as pathogens to marine red algae, little is known about the pathogenicity of Pythium on marine green algae. A strain of a Pythium was isolated from a taxonomically unresolved filamentous Ulva collected in an intertidal area of Oslo fjord. Its pathogenicity to a euryhaline Ulva intestinalis collected in the same area was subsequently tested under salinities of 0, 15, and 30 parts per thousand (ppt). The Pythium isolate readily infected U. intestinalis and decimated the filaments at 0 ppt. Mycelium survived on U. intestinalis filaments for at least 2 weeks at 15 and 30 ppt, but the infection did not progress. Sporulation was not observed in the infected algal filaments at any salinity. Conversely, Pythium sporulated on infected grass pieces at 0, 15, and 30 ppt. High salinity retarded sporulation, but did not prevent it. Our Pythium isolate produced filamentous non-inflated sporangia. The sexual stage was never observed and phylogenetic analysis using internal transcribed spacer suggest this isolate belongs to the clade B2. We conclude that the Pythium found in the Oslo fjord was a pathogen of U. intestinalis under low salinity.

Characteristics of Summer Marine Algal Community and Barren Ground in the Southern Coast of Jeju, Korea (제주 남부해역 조하대 하계 해조군집 및 갯녹음 특성)

  • Jung, Seung Wook;Jeon, Byung-Hee;Choi, Chang Geun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.25 no.2
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    • pp.212-219
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    • 2019
  • This study was conducted to investigate marine algal community characteristics and the status of barren ground in the summer at study sites on Jeju Island, Korea. Sampling was carried out from July to September 2017 using a qualitative and quantitative survey (including coverage of non-geniculated coralline algae and density of grazer) by scuba diving. A total of 121 species were identified, including 11 (9.1 %) green algae, 24 (19.8 %) brown algae, and 86 (71.1 %) red algae. Hyeongjeseom had the greatest diversity, with 60 species, and Harye the least, with 18 species. The mean biomass at the study sites was $1,503.0g{\cdot}m^{-2}$, while the mean for the neighboring islets ($3,268.7g{\cdot}m^{-2}$) was higher than that of the main island ($914.7g{\cdot}m^{-2}$). Also, dominant species was identified: Sargassum macrocarpum at the neighboring islets, and Ecklonia cava at the main island, with differences showing not only in biomass but also species composition. In conclusion, the marine algal community status in summer at the study sites was evaluated based on the algal community characteristics (species composition, biomass, biomass ratio of kelp species), coverage of non-geniculated coralline algae, and density of grazer. As a result, both Hyeongjeseom and Marado require preservation and management to maintain their excellent marine algal communities, and other sites on the main island require the creation and/or restoration of marine algal communities. In addition, as the generation of barren ground accelerates, it is urgent not only to grasp existing monitoring research but also to identify the status of the marine algal community where it is not known at present.

Effects of Heated Effluents on the Intertidal Macroalgal Community Near Gori Nuclear Power Plant (고리원전의 온배수 방출이 주변 해조군집에 미치는 영향)

  • Kim, Young-Hwan;Ahn, Jung-Kwan;Yoon, Hee-Dong;Jang, Min-A
    • ALGAE
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    • v.22 no.4
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    • pp.297-304
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    • 2007
  • This study is intended to clarify the effects of heated effluents on intertidal benthic marine algal community in Korea. The species composition and biomass of marine algae at the discharge canal of Gori nuclear power plant on the southeastern coast of Korea were investigated seasonally from February 2001 to October 2006. As a result, 54 species (7 blue-green, 12 green, 9 brown and 26 red algae) of marine algae were found at the discharge canal during the past six years. In general, the number of species observed was abundant during winter to spring and less in autumn. Enteromorpha compressa, E. intestinalis, E. prolifera and Caulacanthus ustulatus were common species found more than 80% frequency during the study period. Seasonal fluctuations of mean biomass were 1-440 g dry wt m–2 and dominant species in biomass were Enteromorpha spp. (contribution to a total biomass proportion 28%), Sargassum horneri (14%) and Amphiroa beauvoisii (14%). It is evident from the floristic composition and biomass data that unique micro-environment of the discharge canal support different communities from those on the intake or control area. Results from the large numbers of surveys before and during plant operation showed that, in the regions influenced by thermal effluents such as the discharge canal of power plants, the process of ecological succession has been proceeded. It is assumed that the uni-directional water flow and the time of overhaul largely affect the development and succession of benthic marine algal communities of the discharge canal.

The studies on the preference for attachment to the habitat marine environment and habitat space of Sulculus diversicolor supertexta in Jeju Island (제주도 오분자기의 서식 해양 환경과 서식공간에 대한 부착 선호도에 관한 연구)

  • HEO, Nam-hee;KIM, Keun-hyoung;KANG, Kyoung-Bum;KIM, Suk-jong
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.58 no.2
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    • pp.106-112
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    • 2022
  • As a series of basic research to draw the pilot design measures for developing the habitat apparatus of Sulculus diversicolor supertexta inhabiting the coastal area of Jeju island, this study conducted a water tank experiment to understand the habitat marine environment of Sulculus diversicolor supertexta and the preference of habitat space focusing on the research fisheries performing the discharge of marine products. In the composition degree of marine algae in both fisheries, Donggwi-ri showed the highest gulfweed (79.3%) as brown algae and there were some coralline algae (17.2%) as red algae. Hansu-ri yielded the highest gulfweed (48.1%) as brown algae, which was followed by sea lettuce (10.4%) as green algae. In the preference of habitat space, the shelter angles 40° showed the highest adhesion as number of 82.9, which was followed by 60° and 70° as 69.2 and 68.2 respectively (P<0.05) by reviewing the environmental characteristics of habit of Salculus diversicolor supertexta in the coastal fishery of Jeju Island, when considering the adhesion rate in each of five shelters with different angles. In the future, there should be continuous research and monitoring for designing the fish shelters suitable for the coastal fisheries of Jeju island, and it would be also necessary to add the field-centered sustainable concrete research.