• ALGAE
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• 제25권1호
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• pp.1-9
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• 2010

Although Pterocladiella is a well-known agar-producing red algal genus, its taxonomy in Korea appears to be confused. In the present study, we demonstrate the occurrence of Pterocladiella nana and P. tenuis, as well as P. capillacea in Korea on the basis of morphological and plastid rbcL sequence comparisons. P. capillacea commonly occurs along the coasts of Korea and has regular pinnate branches with abundant second-order branches, growing up to 10 cm in length. P. nana occurs in the intertidal zone of Jeju and is distinguished by the small size of its thalli (up to 5 cm) and regular branches with up to third-order branches. P. tenuis is distributed mostly subtidally on the southern coast of Jeju and has irregular branches with rarely second-order branches, growing up to 19 cm in length. We determined rbcL sequences from 19 specimens (15 from Korea and four from France) and downloaded 28 sequences from GenBank. Analyses of all 47 rbcL sequences revealed that each of three species was consistently resolved. P. capillacea and P. tenuis always formed a sister clade with P. nana at the base. Given that 12 rbcL haplotypes from 28 specimens of P. capillacea have been found to date, analysis of a fast-evolving gene from across the range of the species should highlight its genetic diversity.

• ALGAE
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• 제35권2호
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• pp.145-155
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• 2020

Specimens of red algae corresponding to the peyssonnelioid genus Sonderophycus were collected at Kure Atoll, Hawai'i, at a depth range of 88-94 m depth during mesophotic surveys of the Papahānaumokuākea Marine National Monument, Hawaiian Islands, and were analyzed using morphological and molecular approaches. Analyses of mitochondrial cytochrome oxidase subunit 1 and chloroplast rbcL DNA sequences demonstrated that the Hawaiian specimens were identical to one another yet distinct from the three other species currently recognized within the genus (S. capensis [Montagne] M. J. Wynne, S. coriaceus [Womersley & Sinkora] M. J. Wynne, and S. fervens Dixon), as well as the likely congener, Peyssonnelia caulifera Okamura, and are proposed here as a new species: Sonderophycus copusii A. R. Sherwood. Sonderophycus copusii is morphologically distinct from other members of the genus by the following combination of characters: the presence of occasional secondary perithallial growth, emergence of rhizoids from the hypobasal cuticle at a strongly acute angle, a lack of horizontally directed filaments in the lower perithallus, and the lack of a stipe. This is the first record of the genus Sonderophycus in the Hawaiian Islands. Sonderophycus copusii was documented as a dominant member of the algal community at Kure Atoll, and thus may play a significant ecological role in the deep-water benthic community of Kure Atoll, along the lines of reports of deep water peyssonnelioid beds in the Mediterranean, Red Sea, and Caribbean. This study further highlights the unexplored diversity of the Peyssonneliales in Hawai'i, and emphasizes more generally the degree of as yet undiscovered biodiversity of algae at mesophotic depths.

• 생태와환경
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• 제35권3호통권99호
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• pp.187-197
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• 2002

아산호에서 1997년 3월부터 1997년 11월까지 6회에 걸쳐 식물플랑크톤 군집구조를 파악하기 위한 연구를 수행하였다. 19개 정점에서 관찰된 식물플랑크톤 분류군은 총 204종군으로, 각 분류군별 출현비는 녹조류 51%, 규조류 29%, cyanobacteria 12%, 와편모조류가 2%, 유글레나류 4%, 기타 편모조류가 2% 이었다. 식물플랑크톤의 현존량은 741ce11s/m떼서 613,066ce11s/ml의 범위로 매우 높은 수준으로 나타났다. 현존량은 7월에 가장 높았고 9월, 6월, 3월, 11월, 5월 순으로 나타났다. 계절에 관계없이 지속적으로 녹조상태인 것으로 판단되며, 녹조원인생물은 Micractium pusillum, Stephandiscus hantzschii, Dictyospharium pulchellum, cryptomonad (> 20 ${\mu}$, Microcystis aeruginosa, Oscillatoria tenuis, Oscillatoria sp., Aphanocapsa sp. Euglena sp., Volvox aureus 이었다. 여름철에 cyanobacteria에 의한 녹조현상이 현저하였다. 식물플랑크톤의 종다양성은 0.13${\sim}$의 범위로 시${\cdot}$공간적으로 차이가 매우 컸다. 집괴 분석한 결과 전반적으로 아산호 하류수역과 상류수역 투 개의 수역으로 구분이 되었다.

• Journal of Ecology and Environment
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• 제42권4호
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• pp.240-258
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• 2018

Background: Several investigations carried out from large brackish lagoons in South Korea. However, no studies have yet examined phytoplankton in lagoons that changed to freshwater, such as Cheonjin Lake. The present study examined the algae from Cheonjin Lake. Methods: Samples were collected at monthly inetrvals from May 2017 to April 2018, from the surface layer using a plankton net (mesh size $20{\mu}m$), and sequeezing submerged macrophytes. Microscopic examinations were conducted at a magnification of 200 to 1000x using a Zeiss microscope (Axio Imager. A2), and photographs were taken with an AxioCam HRC camera. Silica-scaled samples of Chrysophyta for SEM were placed on coverglass, air dried, coated with gold, and then examined with a Hitachi SV8220 SEM. Results: A total of 376 taxa from six major algal groups (Chlorophyta, Chrysophyta, Euglenophyta, Cyanophyta, Dinophyta, and Cryptophyta) were identified. Among these algae, 28 taxa of desmids, 9 taxa of Euglenophyceae, 4 taxa of Chlorophyceae, 2 taxa of Chrysophyceae, and 1 taxon of Xanthophyceae are reported for the first time in Korea. A new species, Cosmarium hexagonum sp. nov was described. The phytoplankton communities were characterized by an abundance of Desmids (within Charophyceae) accounted for 148 taxa from 22 genera. Species richness were particularly high in the Autumn. Conclusion: In this study, a total 376 taxa of 148 desmids (Charophyceae), Chlorophyceae (103 taxa), Chrysophyceae (53 taxa), Euglenophyta (49 taxa), Dinophyta (8 taxa), and Cryptophyta (2 taxa) were identified from Cheonjin Lake. Twenty-eight taxa of desmids including a new species (Cosmarium hexagonum sp. nov.), 9 taxa of Euglenophyceae, 4 taxa of Chlorophyceae, 2 taxa of Chrysophyceae, and 1 taxon of Xanthophyceae were newly recorded in Korea.

• 한국수산과학회지
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• 제52권5호
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• pp.534-538
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• 2019

The distribution and characteristics of spawning beds of the Pacific herring Clupea pallasii, were observed by scuba diving in Jinhae Bay, Korea, with a focus on marine vegetation as adhesive substrates and egg density during the spawning season. In 2017, the fertilized eggs of C. pallasii were mainly found attached to the leaves of algae species Carpopeltis cornea, Gracilaria textorii, and Acrosrium polyneurum at the rocky shore in Wonpo-dong and Jeodo. The mean density of fertilized eggs in C. pallasii spawning beds was $153,776eggs/m^2$ off Wonpo-dong and $856,430eggs/m^2$ off Jeodo, giving an estimated total of $5.345{\times}10^9$ eggs in Wonpo-dong and $3.3074{\times}10^{10}$ eggs in Jeodo. We examined spawning beds with an area of $38,619m^2$ off Wonpo-dong and $34,760m^2$ off Jeodo. The choice of spawning bed may be affected by the composition of marine vegetation, such as the algal diversity of rocky shore environments, which could affect adhesive substrates and egg density during the spawning season. The results of the present study suggest that the spawning season of C. pallasii in Jinhae Bay is in January to mid-February.

• 한국물환경학회지
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• 제37권3호
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• pp.190-203
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• 2021

Water quality, benthic macroinvertebrate communities, and other factors were investigated to explore the effects of the effluent discharge from a sewage treatment plant into Jwagwang stream in Busan in 2019. During the study period, the flow rate of this stream was in the range of 10,400 m³/day to 52,200 m³/day except for the discharge of about 24,000 m³/day of the effluent. After discharge, the flow velocity increased by about 65% and the water depth increased by about 40%. At sites downstream of the discharge point, BOD, COD, TOC, T-N, T-P, and other water quality values were worse than those of the upstream sites. The periphytic algal chlorophyll-a concentrations in the natural substrata were higher than those of the upstream sites, especially in May and August. However, at sites downstream of the discharge point, the individual numbers of Annelida were decreased and individual numbers of the insecta of arthropoda were increased. Also, species numbers and the diversity and dominance indexes were improved in the sites downstream of the discharge point. The functional feeding groups (FFGs) of collector-filterers were increased and the habitat orientation groups (HOGs) of sprawlers, burrowers, and clingers were especially increased at the sites with additional reclaimed wastewater effluent flow. Regardless of the effluent discharge, BMI, an indicator of ecological stream health using benthic macroinvertebrate species, did not show large gaps between the study points. Although the water quality of the sites downstream of the discharge point was much worse than those upstream, their ecosystem soundness was better than those of the upstream sites from an ecological perspective.

• Journal of Species Research
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• 제11권4호
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• pp.266-277
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• 2022

The current surveys of Ulva in the subtidal area around Jeju Island give a chance to discover unrecorded green algal species of the Korean macroalgal flora. As a result of this investigation, we found Ulva adhaerens Matusmoto & Shimada, inhabiting the subtidal regions, up to 15 m deep, and conducted the DNA barcoding on plastid rbcL-3P and tufA regions with describing the morphological characteristics. Our specimens of U. adhaerens forms a monophyletic clade with the Japanese type specimen and U. piritoka Ngāti Kuri, Heesch & W.A. Nelson from New Zealand exhibiting each 0.3% sequence divergences, respectively, in the plastid rbcL-3P. The genetic variation of U. adhaerens clade is 1.0-3.9% in rbcL-3P and 4.8-9.8% in tufA to each Ulva species, including the generic type, U. lactuca Linneaus. The morphology of Korean U. adhaerens specimens is identical to the type specimens of U. adhaerens from Japan having the development of rhizoidal filaments from both of the cell layers of the distromatic blade and the extension of rhizoidal clumps with adhesive trait between blades by extended rhizoidal clumps at the basal blades. The thallus attachment to substrate is by numerous minute discoidal plates made up of rhizoids originating from the inner part of distromatic blades in basal. Although there are still some problems to resolve the relationship between U. adhaerens and U. piritoka in the rbcL dataset and the phylogenetic pattern of the Group II intron of rbcL, we propose the new record of U. adhaerens in Korean macroalgal flora based on the morphological characteristics of Korean specimens. Continued study of the genus Ulva by morphological and molecular assessment will delimit the species of Ulva, elucidate the relationships between them, and uncover the species diversity.

• ALGAE
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• 제36권4호
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• pp.299-314
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• 2021

Some species in the dinoflagellate genus Alexandrium are bioluminescent. Of the 33 formally described Alexandrium species, the bioluminescence capability of only nine species have been tested, and eight have been reported to be bioluminescent. The present study investigated the bioluminescence capability of seven Alexandrium species that had not been tested. Alexandrium mediterraneum, A. pohangense, and A. tamutum were bioluminescent, but A. andersonii, A. hiranoi, A. insuetum, and A. pseudogonyaulax were not. We also measured the bioluminescent intensity of A. affine, A. fraterculus, A. mediterraneum, A. ostenfeldii, A. pacificum, A. pohangense, A. tamarense, and A. tamutum. The mean 200-second-integrated bioluminescence intensity per cell ranged from 0.02 to 32.2 × 10⁴ relative luminescence unit per cell (RLU cell^-1), and the mean maximum bioluminescence intensity per cell per second (BL_Max) ranged from 0.01 to 10.3 × 10⁴ RLU cell^-1 s^-1. BL_Max was significantly correlated with the maximum growth rates of Alexandrium species, except for A. tamarense. A phylogenetic tree based on large subunit ribosomal DNA (LSU rDNA) showed that the bioluminescent species A. affine, A. catenella, A. fraterculus, A. mediterraneum, A. pacificum, and A. tamarense formed a large clade. However, the toxicity or mixotrophic capability of these species was split. Thus, their bioluminescence capability in this clade was more consistent than their toxicity or mixotrophic capability. Phylogenetic trees based on LSU rDNA and the luciferase gene of Alexandrium were consistent except for A. pohangense. The results of the present study can provide a basis for understanding the interspecific diversity in bioluminescence of Alexandrium.

• ALGAE
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• 제38권4호
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• pp.253-264
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• 2023

The Ceramiales is the most diverse and species-rich group (2,669 spp.) of red algae, and it is widely distributed from tropical to polar oceans. Mitochondrial genomes (mitogenomes) and other genes have contributed to our knowledge regarding the classification and phylogeny of this diverse red algal group; however, the mitogenome architecture remains understudied. Here, we compared 42 mitogenomes, including 19 newly generated in this study, to expand our knowledge. The number of genes in mitogenome varied from 43 to 68 due to gene duplication. The mitogenome architecture was also variable, categorized into four types (A-D): type A = ancestral type with a basic composition; type B = those with inverse transpositions; type C = those with inverted duplications; and type D = those with both inversion and duplication. The palindromic and inverted repeats were consistently found in flanking regions of the rearrangement, especially near the cob and nad6 genes. The three rearranged mitogenome architectures (types B, C, D) are the first report of these in red algae. Phylogenetic analyses of 23 protein-coding genes supported the current familial classification of the Ceramiales, implying that the diversity of mitogenome architecture preceded the phylogenetic relationships. Our study suggests that palindromic and inverted repeats may drive mitogenome architectural variation.

• 한국수산과학회지
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• 제45권3호
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• pp.262-270
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• 2012

Seaweeds provide habitats in which marine animals can spawn and develop, and serve as a food supply for algaegrazing species such as sea urchins and abalone. Recently, seaweed species have disappeared from coastal ecosystems, leaving barren ground, defined as habitats that have lost their algae forests and where coralline algae containing calcium carbonate components have become encrusted on rocks. The biological causes of barren ground include grazing by herbivores and excessive seaweed harvest. The environmental harm caused by the spread of barren ground includes accelerated eutrophication following the reduction in seaweed, which plays an important role in oceanic purification. In the present study, we identified the relationships between various seaweed species and the occurrence of barren ground. Subtidal benthic macroalgal flora and community structure were observed seasonally on barren ground along vertical transects of rocky shores of Bihwa, Samchuck, and the east coast of Korea from February to November 2006. Fifty-eight seaweed species were identified, including 7 green, 15 brown, and 36 red algae species. There were between 6 and 28 species among seasons. Over the whole study period, average seaweed biomass (g wet wt $m^{-2}$) was 241.90 g, with a seasonal range of 25.26 to 760.34 g. Seaweed biomass declined with increasing seawater depth and ranged between 91.26 and 422.08 g. The vertical distribution of algae was characterized by Undaria pinnatifida and Sargassum honeri at 5 m, S. honeri and U. pinnatifida at 10 m, and U. pinnatifida and Agarum clathratum at 15 m depth. Seasonal patterns in community indices were not found. Community indices showed different patterns along vertical shoreline gradients; the dominance index increased but the richness, evenness, and diversity indices decreased with seawater depth. Sea urchin density was 8 to 24 individ. $m^{-2}$ in Bihwa. These urchin populations had significantly aggregated spatial patterns and recurrent destructive grazing appeared to be occurring.