• Journal of Fisheries and Marine Sciences Education
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• v.28 no.1
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• pp.83-90
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• 2016

A subtidal marine benthic algal vegetation at Ulleungdo Island, the eastern coast of Korea was investigated to clarify the community structure and vertical distribution by quadrat method at seven stations in May and August 2014. The total number of marine algal species was 148 species composed of the green algae of 12 species, the brown algae of 40 species and the red algae of 96 species. Mean biomass in dry weight was $94.8g\;dry\;weight\;m^{-2}$ in study sites, $98.1g\;dry\;weight\;m^{-2}$ in upper tidal level, and $86.6g\;dry\;weight\;m^{-2}$ in middle level. The R/P and (R+C)/P value reflecting flora characteristic were 1.9 and 2.3, respectively. Three groups produced by cluster analysis, one including sites Neunggeol, Daepung, Jukdo, second including sites Gongam, Ssangjeongcho and the other including sites Gwaneum, Hangnam, showed meaningful difference in similarity (about 40%), each other. The number of marine algal species and biomass in Ulleungdo Island area were markedly reduced comparing that in the previous studies. This result may suggest probably change of algal vegetation in future, considering the physical and chemical pollutions loaded in the coastal marine environment of this area.

• ALGAE
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• v.20 no.3
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• pp.177-181
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• 2005

Two species of marine algae, Fauchea spinulosa Okamura et Segawa (Rhodymeniaceae, Rhodophyceae) and Stictyosiphon soriferus (Reinke) Rosenvinge (Chodariaceae, Phaeophyceae) were newly collected from the southern coast and Cheju Island of Korea. Fauchea spinulosa was collected from subtidal zone in the insular region of the southern coast. Plants were erect from the discoidal holdfast with short stipe, pinkish to deep red, cartilageneous, dichotomously and flabellately branched, and 10-15 cm high, 5-15 mm broad. Tetrasporangia are cruciately divided and nemathecia occurred on a side of the branches. Cystocarps were mostly coronate in marginal area and spermatangia were scattered on both sides of branches. Stictyosiphon soriferus commonly occurs on muddy and sandy intertidal flat of Namhaedo located on the southern coast. Plants are epilithic, light brown, terete, 3-5 cm high, and branched heavily in irregular or alternate manner, arising from a small holdfast with rhizoidal clumps. Plurilocular sporangia were scattered in patches and slightly swollen above the cortex of the whole filament. Unilocular sporangia were not found.

• ALGAE
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• v.23 no.4
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• pp.301-310
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• 2008

The marine benthic algal flora and biomass of Chuja Island, southern coast of Korea, was investigated. The collections of intertidal marine algae were made at two sites, Yecho of Hachujado and Hupo of Sangchujado, from October 2006 to July 2007. A total of 162 species, including 15 green, 47 brown and 100 red algae, were identified in this study. The occurrence of species according to season was abundant during spring to summer and less in autumn. The vertical distribution of intertidal zone in Chujado was characterized by Gloiopeltis spp., Myelophycus simplex, Ishige okamurae, Chondrus ocellatus, Grateloupia elliptica, Hizikia fusiformis and Sargassum spp. The average biomass of macroalgae was measured as 400 g wet wt m$^{-2}$. The dominant species based on the biomass were Sargassum yezoense, S. coreanum and Hizikia fusiformis. ESG II (ecological state group) as an opportunistic species, including sheet form, filamentous form, and coarsely branched form, occurred 85.8% in the intertidal seaweeds. These results provide a baseline for future monitoring studies in the Chuja Island.

• The Journal of the Acoustical Society of Korea
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• v.24 no.8
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• pp.447-453
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• 2005

Laboratory measurements were performed in a uni-algae medium Cochlodinium polykrikoides (Phytoplankton, dinoflagellates) using an Underwater Ultrasound $(5\~15\;MHz)$ to study Characteristics of Acoustic Backscattering of Harmful algae. In an effort to detect the harmful algal scatterers with population density of less than 300 cells/ml that corresponds to the precaution stage of red tide, backscattered signals from various scatterer-density samples were obtained and analyzed. Correlations between volume backscattering strength (Sv) and population density (cells/ml) of scatterers in the medium have been investigated. Comparison of Volume Backscattering Strengths calculated with the fluid-sphere model [1] and the measured values showed an agreement.

• Journal of Plant Biology
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• v.28 no.2
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• pp.149-164
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• 1985

Intertidal algal community of Muchangpo in western coast of Korea was investigated qualitatively and quantitatively. Seasonal changes of algal occurrence, dominant species in cover, vertical zonation pattern and biomass were analysed. A total of sixty-four species of marine algae, one blue-green alga, three green algae, nineteen brown algae and forty-one red algae, were identified. The dominant species in cover were Sargassum thunbergii, Gelidium divaricatum and Pelvetia siliquosa throughout the year. Gloiopeltis furcata was abundant at upper and middle littoral zones and Corallina pilulifera at lower littoral zone. Classification by unweighted pair-group average method and ordination by reciprocal averaging based on the cover data indicated that, on the whole, the intertidal algal vegetation showed different patterns along tidal levels. Seasonal fluctuations of mean biomass were 57.2~92.8 g-dry/$m^2$, and the highest in summer and the lowest in spring season. Seasonal change of community structure was also discussed.

• ALGAE
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• v.28 no.2
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• pp.131-147
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• 2013

Major progress has been made in the past decade towards understanding of the biosynthesis of red carotenoid astaxanthin and its roles in stress response while exploiting microalgae-based astaxanthin as a potent antioxidant for human health and as a coloring agent for aquaculture applications. In this review, astaxanthin-producing green microalgae are briefly summarized with Haematococcus pluvialis and Chlorella zofingiensis recognized to be the most popular astaxanthin-producers. Two distinct pathways for astaxanthin synthesis along with associated cellular, physiological, and biochemical changes are elucidated using H. pluvialis and C. zofingiensis as the model systems. Interactions between astaxanthin biosynthesis and photosynthesis, fatty acid biosynthesis and enzymatic defense systems are described in the context of multiple lines of defense mechanisms working in concert against photooxidative stress. Major pros and cons of mass cultivation of H. pluvialis and C. zofingiensis in phototrophic, heterotrophic, and mixotrophic culture modes are analyzed. Recent progress in genetic engineering of plants and microalgae for astaxanthin production is presented. Future advancement in microalgal astaxanthin research will depend largely on genome sequencing of H. pluvialis and C. zofingiensis and genetic toolbox development. Continuous effort along the heterotrophic-phototrophic culture mode could lead to major expansion of the microalgal astaxanthin industry.

• ALGAE
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• v.37 no.3
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• pp.205-211
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• 2022

The trend in naming genera based almost exclusively on molecular data, and not on morphological diagnostic characters, is increasing. In bifurcating phylogenetic trees generic cut-offs are arbitrary, but at the bare minimum nomenclatural changes should be supported by multiple phylogenetic methodologies using appropriate models for all the various gene partitions, strong support with all branch support methods, and should also result in adding to our knowledge of the interrelationships of taxa. We believe that a recent taxonomic treatment of the genus Pyropia (Yang et al. 2020) into several genera is unwarranted. We reanalysed the data presented in the recent article, using additional phylogenetic methods. Our results show that many of the newly established genera are not well supported by all methods, and the new circumscription of the genus Pyropia renders it unsupported. We also tested additional outgroups, which were previously suggested as sister to Pyropia, but this did not substantially change our conclusions. These generic nomenclatural changes of the previously strongly supported genus Pyropia, do not shed light on the evolution of this group and have serious consequences in these commercially important algae, that are also governed by a plethora of regulation and by-laws that now need to be amended. We suggest that the over-splitting of groups based only on poorly produced and modestly supported phylogenies should not be accepted and that the genus Pyropia sensu Sutherland et al. (2011) be restored.

• 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.

• Journal of Marine Bioscience and Biotechnology
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• v.14 no.2
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• pp.102-111
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• 2022

Beakryoung-do is located in the north along the western coast of South Korea. Owing to its geographical limitations, not many studies have been conducted on marine algae in this region. This study aims to investigate the marine algal flora and the community structure in the intertidal and subtidal zones of Nampo-ri, Beakryoung-myeon, Ongin-gun, Incheon regions of South Korea. The study was conducted from August 2015 to June 2016 during all seasons. A total of 95 algal species, including 7 green algae, 12 brown algae, and 76 red algae were collected and identified; 52 algal species were found in the intertidal zone and 83 in the subtidal zone. The vertical distribution of algae from upper to lower intertidal zone was Neorhodomela aculeata - Caulacanthus okamurae, Gelidiophycus freshwateri - Neorhodomela aculeata, Caulacanthus okamurae - Sargassum thunbergii, Caulacanthus okamurae. Findings indicated that Sargassum thunbergii and Neorhodomela aculeata were the biomass-dominant species in the intertidal zone and Corallina officinalis and Undaria pinnatifida were biomass-dominant in the subtidal zone. Average values of marine algae biomass in the intertidal and subtidal zones were 252.6 g wet weight m^-2 and 291.9 g wet weight m^-2, respectively. Further, 38 new species were found in Beakryoung-do, with 25 of them specifically found in the subtidal zone. More studies on marine algal flora in the subtidal zone are needed to understand the changes in marine flora along the western coast.

• 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.