• The Korean Journal of Malacology
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• v.24 no.2
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• pp.81-87
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• 2008

Distribution, population structure, and growth of the bivalve Protothaca euglypta were investigated for clams collected from the northwestern part of the East Sea of Russia. This species is distributed in further northern area than it was found earlier. In the southern area, this clam is found in the intertidal zone, up to 8 m in depth. It is one of the most numerous infaunal species of bivalves, and protected to wave action in the gravel-pebble and sand with rubble biotope. Population density of P. euglypta reaches 500 $spc./m^2$, and biomass 2 $kg/m^2$. Size and age composition of the local settlements and allometric growth of P. euglypta depend on a biotope. The growth rate of P. euglypta considerably reduces in case of the northern boundary area, whereas life span increases.

• The Korean Journal of Malacology
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• v.4 no.1
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• pp.17-29
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• 1988

The study had been carried out three times, from April 1987 for the purpose of analysis on the community structure and the distribution patterns of the Molluscan shells at the intertidal zone of Cheju Island. 1) The Molluscan shells collected and identified at all studied sites were composed of 3 classes, 10 orders, 23 families and 42 species.2) In all studied sites, individual numbers according to species were Nodilittorina exigua, Monodonta neritoides, Lunella coronata coreensis, Heminerita japonica in order. On the other hand, the dominant species of the rocky sits were N. exigua, M. neritoides and the rocky and silty-sand sites was Batillaris multiformis.3) In the vertical zonation, in the supralitorial zone, N. exigua was dominant species and the wpper-tidal zone, N. exigua, H. japonica and B. Multiformis were dominant species, but B. multiformis was dominant in the rocky and silty sand sites. In the middle tidal zone, M. neritodes, H. japonica, L. coronata coreensis were dominant and in the lower tidal zond, M. neritodes, L. coronata coreensis, Liolophura japonica were dominant.4)In the analysis on community of Molluscan shells, Chagwi, Pyoson an dAewol sites were more diverse than other sites in the species diversity and environmental inhibits were also favorable.5) Community similarities among the studied sites based on the similarities values were divided into two groups according to the difference of the ground: Hagwi, Chongdal and Sehwa sites group and the others sites group.

• 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.

• Ocean Science Journal
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• v.42 no.3
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• pp.135-152
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• 2007

The ecological aspect of meiofaunal communities in Can Gio mangrove forest, Ho Chi Minh city, Vietnam has not been investigated before. The composition, distribution, density and biodiversity of meiofaunal communities were studied along an intertidal transect at the Khe Nhan mudflat. Each time, three replicate samples were collected in four stations along a transect following the water line from low tide level up to the mangrove forest edge. In total, 18 meiofaunal taxa were found with the dominant taxa belonging to Nematoda, Copepoda, Sarcomastigophora and Polychaeta. The densities of meiofauna ranged from $1156inds/10cm^2$ to $2082inds/10cm^2$. The increase in densities from the mangrove forest edge towards the low water line was significant Along the mudflat transect, the biodiversity (expressed by different indices) was relatively high at different taxonomic levels but did not vary significantly along the mudflat except for taxa richness. Eighty nematode genera belonging to 24 families with Comesomatidae having the highest abundance 33.8 % were found. Theristus and Neochromadora decreased in densities from the lower water line towards the mangrove forest edge, while Paracomesoma and Hopperia are typical and more abundant at the middle of the mudflat. Halalaimus increased from high on the mudflat to the low water line.

• ALGAE
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• v.36 no.1
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• pp.13-24
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• 2021

The present-day genetic structure of macroalgal species reflects both geographical history and oceanic circulation patterns as well as anthropogenic introduction across native ranges. To precisely understand the genetic diversity and how the factors shape the current population structure of Gloiopeltis furcata sensu lato, we determined the mitochondrial 5' end of cytochrome c oxidase subunit I (COI-5P) sequences for 677 individuals sampled from 67 sites spanning almost the entire distribution range in Korea and Japan. Results from the phylogenetic analysis and haplotype distribution revealed eleven distinct lineages within G. furcata s.l. along the Korea-Japan coastal areas and displayed divergent phylogeographic patterns among lineages. Despite the closely related lineages distributed in same habitats as high rocky intertidal zone, they display different phylogeographic patterns among lineages. The populations from the south of Korea-Japan harbored the highest genetic diversity and unique endemism in comparison with other populations in the distribution range. This could be the evidence of southern refugia for G. furcata s.l. in the Northwest (NW) Pacific and the recent migration from native to introduced region. The reason is that an exceptional distribution pattern was found high genetic diversity in Hakodate of Japan where is the northern location in the NW Pacific. Our results imply the contemporary influence on the distribution due to current circulation pattern and anthropogenic effects. These phylogeographic findings provide the important insight into cryptic species diversity and the detailed distribution pattern of Gloiopeltis in the NW Pacific.

• Journal of the Korean earth science society
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• v.31 no.2
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• pp.139-150
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• 2010

This study investigated the depositional environment of the area of Anmyeondo in the mid-western coast of Korea. A total of 142 surface sediments were analyzed, and leveling survey was conducted as well in 12 transects at the sandy tidal flat in the area. The surface sediments are classified into several different types (slightly gravelly Sand, Sand, slightly gravelly sandy Mud, etc.) and they show fining-distribution toward the offshore. Textural parameters are characterized by being coarse, well sorted, positively skewed in the supratidal and intertidal flat, whereas being finer, poorly sorted, negatively skewed in the subtidal flat. According to the C-M diagram, the sediment transport modes are characterized by the mixed mode of bedload and graded suspension in supratidal and intertidal flat, and by graded suspension or uniform suspension in the subtidal flat. Histogram shows a bimodal distribution in the lower subtidal flat which is indicative of two sediment transport modes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.969-976
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• 2015

Macroalgal community structure was seasonally examined at Hakampo (Taean) in western coast of Korea from February 2007 to October 2010. Also, the effects of "Hebei Spirit" oil spill on the seaweed community structure were evaluated. A total of 101 macroalgal species were identified, comprising 12 green, 18 brown and 71 red algae. Species richness ranged 58-65 species with maximal in 2008 and minimal in 2009. Seaweed biomass ranged $75.81-102.06g\;dry\;wt./m^2$ (mean, $88.78g/m^2$) with maximal in 2008 and minimal in 2010. Vertical distribution from the high to low intertidal zone was Neorhodomela aculeata and Polyopes affinis; Corallina pilulifera and Chondrus ocellatus; Sargassum thunbergii and Ulva australis. Coarsely-branched seaweeds comprised the highest proportion of biomass ($37.17g/m^2$, or 41.86% of the total biomass) and ecological state group I (ESG I) seaweed biomass was between 81.67-85.44%. Also, ephemeral macroalgae including Ulva species sharply increased in species number and biomass within 1-2 year from the "Hebei Sprit" oil spill in the mid and low intertidal zone. Hakampo rocky shore is still good condition as evaluated based on macroalgal species number, biomass, and composition in functional form and ESG I seaweeds.

• Korean Journal of Environmental Biology
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• v.18 no.4
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• pp.411-424
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• 2000

In order to investigate the population structure and dynamics of halophilous springtails and ants at seashores in Korea, we made quantitative collection from three different sites having different vegetation and environment. The pH, salinity, and electric conductivity of the three sites were measured in order to find environmental factors influencing on their species composition and distribution. In view of the results so far obtained, the species composition and distribution of springtails seemed to depend not so much on pH and vegetation as on soil texture and salinity. On the other side, ant populations seemed to depend on vegetation in sand area and on inundation in both sand area and salt marshes. In all investigated sites, the species diversity in supra littoral zones was higher than in intertidal zones, and among intertidal zones of sand beach and salt marshes it was the highest at the upper zone of the sand beach.

• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.81-87
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• 2021

The monthly variability in marine algal flora and community structure was examined in the intertidal zones of Doripo, and the biomass of an edible alga, Ulva prolifera, at Gaip-ri of Hampyong Bay on the southwestern coast of Korea was investigated over one year from April 2008 to March 2009. A total of 22 seaweeds were identified including five green, four brown, and 13 red algae. Based on importance value, Ulva australis was dominant over the year and the subdominant species were Ulva linza and Caulacanthus ustulatus at the Doripo coast of Hampyong Bay. The vertical distribution in terms of importance values was in the order of Ulva linza - C. ustulatus - U. australis - Sargassum thunbergii from the upper to the lower intertidal zones. The biomass of U. prolifera ranged between 2.4-98.2 g dry wt. m^-2, with a maximum in June and a minimal in November. In the field, U. prolifera biomass could be positively related to seawater temperature. However, further research on the association between biomass and other environmental factors such as nutrients and light intensity is required.

• Journal of the Korean earth science society
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• v.22 no.2
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• pp.120-129
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• 2001

A sand shoal (1300 m long and 400 m wide) with an orientation of north-south is formed on the lower tidal flat of Gomso Bay, southwestern coast of Korea. Surface bedforms, sedimentary structures, sedimentation rate, grain size distribution and can-corer sediments have been measured and analysed along the sand shoal proper zone B and its offshore zone A and onshore zone C during the period of 14 months. These three zones can be differentiated based on sedimentological characteristics: A zone - fine sand (3${\varphi}$ mean), linguoid-type ripples, 70 mm/month in sedimentation rate and no bioturbation, B zone - medium sand (2.5${\varphi}$ mean), dunes (4${\sim}$5 m in wavelength), 30 mm/month in sedimentation rate and no bioturbation, and C zone - coarse silt (5${\varphi}$ mean), sinuous-type ripples, 10 mm/month in sedimentation rate and well-developed bioturbation. These characteristics indicate that the zone C represents a relatively low-energy regime environment whereas the zone A corresponds to a relatively high-energy environment. The zone B would play an important role for a barrier to dissipate the approaching wave energy, resulting in maintaining of low-energy conditions in the inner part of Gomso-Bay intertidal flat behind.