• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.595-603
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• 2017

The macroalgal community structure was examined at the subtidal zones of six study sites, on the Southern coast of Korea from between May and August 2015. A total of 132 seaweeds, comprising 10 green, 28 brown and 94 red Seaweed, were identified. The seaweed biomass was $80.32g\;dry\;wt.\;m^{-2}$ in average, and it was maximal at Geomundo ($166.94g\;dry\;wt.\;m^{-2}$) and minimal at Byeongpungdo ($14.52g\;dry\;wt.\;m^{-2}$). On the basis of the biomass, the Ecklonia cava was a representative species, distributed widely in the subtidal zone of the three islands (Yeoseodo, Geomundo, Baekdo). Also, the Sargassum sp. was dominant at Sejondo and Hongdo. The turbidity and light transmittance was divided into two groups. The seaweed community structure of group A (Byeongpungdo, Sejondo, Geomundo) was characterized by high turbidity, low light transmittance and a lower habitat depth than were observed in group B (Hongdo, Baekdo, Yeoseodo). As the water depth increased, the biomass decreased due to the lowered light transmittance. In Byeongpungdo and Sejondo, which showed high turbidity and low light transmittance, the degree of seaweed coverage was decreased with the depth of water. The ESGII ratio of the Ecological Status Group was higher than fourty percentage in Byeongpungdo and Baekdo. Community indices were as follows: dominance index (DI) 0.35-0.90, richness index (R) 7.03-17.93, evenness index (J′) 0.22-0.60, and diversity index (H′) 0.79-2.18. The Macroalgal zonation of the subtidal zone was calculated by the Ecklonia cava and Brown algal population on five islands(Byeongpungdo, Yeoseodo, Geomundo, Beakdo, Hongdo). On the other hand, Undaria pinnatifida and Sargassum sp. dominated at Sejondo. Additionally, the biomass ratio and the species richness of green algae was lower in group A. These differences in the seaweed community structure may have resulted from the effects of turbidity and light transmittance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.1
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• pp.79-87
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• 2024

We seasonally examined marine macroalgal community structures in the subtidal zones at Gapado Island, Jeju, Korea, from February 2013 to November 2019. A total of 164 macroalgal species were identified, including 15 green, 40 brown, and 109 red algae. Species richness ranged from 54-106 species, with the maximum observed in 2013 and the minimum observed in 2015. Cladophora wrightiana var. minor, Ecklonia cava, Amphiroa anceps, Corallina aberrans, Corallina crassisima, Synarthrophyton chejuense, Sonderophycus capensis and Plocamium telfairiae occurred in all seasons. The average annual seaweed biomass was 1,258.22 g wet wt./m², ranging from 917.51 g/m² in 2017 to 1,551.95 g/m² in 2014. E. cava was the most dominant species, accounting for 46.57% of the total seaweed biomass. The subdominant species were P. telfairiae and A. anceps, comprising 8.64% (108.75 g/m²) and 6.65% (83.61 g/m²) of the total biomass, respectively. The vertical distribution of subtidal seaweeds were represented by E. cava and P. telfairiae at 5-20 m, A. anceps at 10-20 m, C. aberrans and C. crassisima at 5 m and C. wrightiana var. minor at 10 m. Cluster analysis revealed three distinct groups: group A (2014-2018), group B (2019) and group C (2013), indicating significant differences in the annual seaweed community.

• ALGAE
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• v.22 no.4
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• pp.313-318
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• 2007

Studies have been made of the species composition and community structure of benthic marine algae at intertidal zone and subtidal zone of Youngdo at Busan. In this area, a total of 69 marine algal species including 10 Chlorophyta, 17 Phaeophyta and 42 Rhodophyta was identified. Dominant species in coverage were Enteromorpha linza, Ulva pertusa, Gelidium divaricatum, Hildenbrandtia rubra and Chondrus ocellatus throughout the year. Enteromorpha linza, Ulva pertusa, Porphyra yezoensis, Gelidium divaricatum, Corallina pilulifera, Grateloupia elliptica and Chondrus ocellatus vertically distributed in intertidal zone, while Ecklonia stolonifera, Gelidium amansii, Prionitis cornea, Gracilaria textorii, Acrosorium polyneurum and Phycodrys fimbriata in subtidal zone. The vertical distribution of subtidal zone were characterized by Ecklonia stolonifera at 1 to 5 m depths. During a year, biomass and length of Ecklonia stolonifera gradually decreased from March to January, but increased from February. Zoosporangial sori were observed from September to December. In conclusion, number of species in this area was remarkably reduced as compared to the previous data at Busan and it’s vicinity.

• ALGAE
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• v.22 no.2
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• pp.117-123
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• 2007

The seasonal change of algal flora and intertidal community structures of Bagryoungdo Island was investigated at Dumujin from February to November 2006. The description of subtidal algal community was made in October by Scientific SCUBA-diving. The total of 43 species, including 6 Chlorophytes, 6 Phaeophytes, 29 Rhodophytes and 2 sea grasses were identified in this survey. The occurrence of species according to season, listed as follows, 26 species in winter, 34 in spring, 18 in summer and 18 in autumn. Three species, Laminaria japonica, Neorhodomela aculeata and Ulva pertusa were dominant. The algal zonation of intertidal zone was figured out by Porphyra spp., Gloiopeltis furcata, Caulacanthus okamurae, Gelidium divaricatum - Neorhodomela aculeata, Enteromorpha compressa - Ulva pertusa, Dumontia simplex, Laminaria japonica from upper to lower zone. The zonation of subtidal zone was figured out by Ulva pertusa - Laminaria japonica - Zostera marina (sea grass), crustacean red algal population in autumn. The average of biomass of macroalgae was measured as 119.4 g∙dry wt/m2.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.5
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• pp.571-578
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• 2018

Seasonal variability in algal community structure of the subtidal zone was examined at four study sites on the southeastern coast of Korea from February to November 2016. A total of 81 species of algae (8 green, 12 brown, and 61 red) were indentified. During the study period, the greatest number of species was observed at Sinamri (57 species) followed by Daesongri (50 species), Dongbaekri (47 species) and Gangyangri (42 species). Of the six functional seaweed forms, the coarsely-branched form was the most dominant, accounting for about 43% of the total species at Daesongri. The annual average biomass in wet weight varied from $700.59g/m^2$ at Sinamri to $1,712.45g/m^2$ at Daesongri. The parameters of seaweed community structures were as follows: dominance index (DI), 0.30-0.54; richness index (R), 4.92-7.05; evenness index (J'), 0.54-0.72; and diversity index (H'), 2.05-2.91.

• ALGAE
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• v.27 no.4
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• pp.269-281
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• 2012

Marado is a small rocky island located off the south coast of Jeju Island and acts as the first gateway of the Kuroshio Current to Korean coastal ecosystems. This island is one of the most unpolluted and well preserved sea areas around the Jeju coast. We extensively observed macroalgal assemblages of species and functional forms in the intertidal and subtidal zones through four seasons on Marado, Jeju Island, Korea to demonstrate the seasonality of vertical distribution patterns and biomass. A total of 144 species (14 Chlorophyta, 40 Phaeophyta, and 90 Rhodophyta) were identified in quadrats and were analyzed seasonally and vertically to define the variation patterns. The annual mean biomass of macroalgae was $2,932.3g\;wet\;wt\;m^{-2}$ and the highest value was recorded in spring and the lowest was in winter. The annual dominant species by biomass was Ecklonia cava followed by Sargassum fusiforme, S. macrocarpum, Amphiroa galapagensis, Chondria crassicaulis, and S. thunbergii. Obvious biomass zonation patterns of macroalgal species were detected in relation to tidal height and depth. Macroalgal biomass, diversity index (H'), and community dynamics were the highest in the shallow subtidal zone. Species number was higher in the subtidal than in the intertidal zone and similar throughout the entire subtidal zone. Our results provide revealing insights into the distribution patterns of macroalgal assemblages in an unpolluted sea area around Jeju Island.

• Ocean and Polar Research
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• v.41 no.2
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• pp.47-61
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• 2019

The Dokdo coast is known for its high biodiversity. However, few studies have examined the biodiversity and macrobenthic community on the subtidal soft-bottom. Therefore, we collected macrobenthos (> 1 mm) using a Smith-McIntyre grab ($0.1m^2$) at 15 stations along the Dokdo coast in September 2016. The sediments consisted of badly sorted (1.7) coarse sand with gravel and the mean sediment grain size was $-0.4{\phi}$. In total, 177 macrobenthic species were collected; their mean density was $1,566ind./m^2$. The number of species and density of macrobenthic fauna decreased significantly with the mean grain size. The dominant species were the amphipods Melita denticulata (16.5%) and Melita shimizui (5.5%), polychaete Salvatoria clavata (5.4%), bivalve Glycymeris aspersa (4.4%), and ophiuroid Ophionereis dubia (4.3%). The dominant macrobenthos species on the subtidal soft-bottom differed from the coastal areas of the East Sea, suggesting that the difference in the sediment grain size affected the macrobenthos. Cluster analysis was performed to divide the study area into four groups, and environmental factors which correlated with species composition and distribution in the study area were the combination of the four parameters of salinity, dissolved oxygen, total organic carbon and depth. A future seasonal investigation is needed to understand the species composition and characteristics of the Dokdo macrobenthos.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.3
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• pp.191-201
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• 2014

Marine algal flora and community structure were investigated seasonally at three sites in subtidal zone of Wangdol-cho on the east coast of Korea from May 2012 to August 2013. A total of 122 species were collected and identified, including 12 green algae, 29 brown algae, and 81 red algae. Of these, 38 species were found throughout the survey period. Average seaweed biomass was 472.19-1,198.77 g wet wt. $m^{-2}$ in spring, 68.99-631.14 g wet wt. $m^{-2}$ in summer, 200.91-401.20 g wet wt. $m^{-2}$ in autumn, and 53.61-922.32 g wet wt. $m^{-2}$ in winter. The vertical distribution based on biomass were Grateloupia lanceolata, Acrosorium venulosum, Lomentaria catenata - Undaria pinnatifida, Dictyopteris pacifica, Sargassum horneri, Ecklonia cava - Desmarestia viridis, E. cava, S. horneri from upper to lower subtidal zone. The flora was classified into six functional groups: filamentous form (34.43%), coarsely branched form (25.41%), sheet form (24.59%), thick leather form (9.71%), crustose form (5.74%) and jointed calcareous form (0.82%). The C/P, R/P and (R+C)/P values reflecting the flora characteristics were 0.41, 2.79 and 3.21, respectively. Also, diversity index (H') and dominance index (DI) indicate that the algal community and environmental condition of Wangdol-cho is stable. We recommend that Wangdol-cho subtidal zone should be more protected from human activities such as turbulence and eutrophication in order to maintain species diversity and abundance of algae.

• Ocean and Polar Research
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• v.33 no.3
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• pp.193-209
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• 2011

The community structure of meiobenthos was studied at 16 stations within sandy tidal and subtidal zones in Jangbongdo in the Yellow Sea, Korea from Aug. 2006 to Jan. 2007. Meiobenthic organisms were collected by three core samples, with a 3.6 cm diameter, from each sediment sample taken with a Smith-McIntyre Grab. Mean grain size of study stations ranged from $1.49{\phi}$ to $3.55{\phi}$. Composition of sand ranged from 80.38% to 99.89%. There was reduction in total abundance and biomass of meiobenthos from summer to winter. Total densities of meiofauna ranged between 17 inds./10 $cm^2$ and 853 inds./10 $cm^2$. Nematodes, gastrotricha, nauplius and harpacticoids appeared as major taxa in decreasing order. This study shows that major taxa comprised 90 percent of total abundance. Most meiofaunal organisms are concentrated in the upper sediment layers and the total abundance and biomass of organisms in the tidal zone is higher than the subtidal zone.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.1
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• pp.85-94
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• 2011

The species composition and distributions of benthic marine plants on the East Coast of Korea were studied. We examined all species found in the intertidal and subtidal zones at four sites seasonally from August 2006 to May 2009. Of the 148 species identified, 92 were rhodophytes, 39 were phaeophytes, 16 were chlorophytes, and 1 was a seagrass. The most species (125) were found at Jukbyeon, while the fewest (99) were found at Chuksan. Overall, the numbers of species were highest during the spring and lowest in autumn. Seventy-five species (50 rhodophytes, 15 phaeophytes, 9 chlorophytes, and 1 seagrass) were found at all four sites. The dominant species providing cover were melobesioidean algae, Sargassum spp., Phyllospadix japonica, and Corallina pilulifera. The vertical distribution of benthic marine plants was characterized by C. pilulifera, Sargassum spp., Hizikia fusiformis, Grateloupia elliptica, Symphyocladia latiuscula, Grateloupia lanceolata, Ulva pertusa, and Chondria crassicaulis in the intertidal zone; Sargassum spp., P. japonica, Prionitis cornea, C. pilulifera, and Acrosorium polyneurum at 1 m depth; Sargassum spp., P. japonica, and melobesioidean algae at 5 m depth; and melobesioidean algae at 10 m depth. There was variation among the sites, presumably due to differences in the local conditions.