• Ocean and Polar Research
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• v.37 no.4
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• pp.295-315
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• 2015

In order to determine the spatio-temporal distribution of macrobenthic faunal communities in Jinhae Bay, quantitative faunal samples were collected seasonally at 23 sites in Jinhae Bay from February, 2011 to November, 2012. Sediment facies were found to be mud except for those at Chilcheon-do near Geoje Island. Mean values of TOC (%) ranged between 1.3 and 3.6%, and these are the highest values recorded excluding special management areas in Korea. Hypoxia occurred every summer in the whole areas of Jinhae Bay except around Geoje Island in the bay mouth. Due to the summer hypoxia, species richness, density and biomass also declined during the summer in Jinhae Bay. Opportunistic species such as Paraprionospio patiens, Sigambra bassi, Nectoneanthes oxypoda and Theora fragilis occurred as the dominant species before and after the hypoxia. However, Capitella capitata appeared as a dominant species only during the winter-spring season every year. From cluster analysis, Jinhae Bay could be divided into two sites groups: one group occupied the normoxic zone and the other one located in the hypoxic zone.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.3
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• pp.157-165
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• 2015

This study investigated and compared sediment properties and macrobenthic community structures within heated effluent plumes at the discharge areas of Kori Nuclear Power Plant (KNPP) and Sinkori Nuclear Power Plant (SNPP) in Korea, which have different thermal effluent discharge systems. There were significant differences in sand, clay and organic carbon contents between sediments at the two discharge areas. Species richness and abundance of macrobenthos were higher at the SNPP discharge area than at that of the KNPP, although the values at both areas were comparable to previous studies in coastal areas of eastern Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.2
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• pp.200-214
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• 1994

In order to clarify the benthic environmental properties as a part of a study on the macrobenthic community in the Chinhae Bay System, water temperature, salinity and dissolved oxygen (DO) in surface and bottom water layers, mean grain size (${\phi}$) and sediment organic carborn (SOC) in surface sediment were analyzed at twelve stations during the period from June 1987 to May 1990. A high sediment organic carbon and hypoxic condition in bottom water due to the development of summer stratification and fine sediment texture toward the inner bay were important environmental characteristics of Chinhae Bay. Hypoxic conditions began to develop in the inner bay from May, and gradually spread toward the outer bay in summer with a peak in September when half the bay was affected by this oxygen deficiency. Recovery from this hypoxic condition in the bottom layer was observed from the beginning of autumn together with a disappearance of the summer stratification. Principal component analyses were carried out from the following five environmental variables:mean water temperature, salinity, dissolved oxygen in the bottom layer and mean grain size, sediment organic carbon in surface sediment. The twelve stations were classified into four areal groups based on the analyses. The division of the areal groups had high correlations to the sediment organic carbon content.

• Korean Journal of Environmental Biology
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• v.28 no.4
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• pp.179-187
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• 2010

The Theory of Island Biogeography describes that the number of species on an island affected by island area and distance from the mainland. This study was performed to compare and analyze the community structure of the macro-invertebrates in three isolated islands, around Korean waters in terms of the Theory of Island Biogeography. Macrobenthic animals were collected using a modified underwater quadrat in August 2009. A total of 104 macrobenthic species were sampled with a mean density of 399 individuals $m^{-2}$ and biomass of 1,506.70 g $m^{-2}$. Based on the abundance and biomass data, there were 10 dominant species accounting for approximately 67.17% of total individuals. The highest densities were found in the amphipoda Amphipoda spp., the bivalvia Modiolus agripetus and Mytilus coruscus, the Sipunculida Phascolosoma scolops and the polychaeta Syllidae unid.. On the contrary, the top ten species made up 95.66% of the total biomass while the three most abundant, the bivalves M. coruscus, Streostria circumpicta and M. agripetus. The conventional multi-variate statistics (cluster analysis and non-metric multi-dimensional scaling) applied to assess spatial variation in macrobenthic assemblages. Cluster analysis and nMDS ordination analysis based on the Bray-Curtis similarity identified 2 station groups. The group 1 was consisted with Gageodo (except for lower station at Transect 2) and Dokdo station and was numerically dominated by the polychaetes Eunice antennata and Syllidae unid., the cirripedia Megabalanus rosa and the bivalvia M. coruscus. However, group 2 was associated with Sohwado station and was characterized by high abundance of the anomura Petrolisthes japonicus, the gastropoda Lirularia pygmaea and the brachiopoda Coptothyris grayi. In conclusion, these results suggested that the species diversity and community structure of macrobenthos in three isolated island seemed slightly related to island area and distance from the mainland.

• Journal of Marine Life Science
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• v.1 no.2
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• pp.95-108
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• 2016

This study was performed to investigate the community structure of macrobenthic assemblages in the Environmental Conservation area, Korea. Benthic animals were collected by van Veen grab sampler at spring (May) and summer (August) 2009. The total species number and mean density were 195 species 5.6 m^-2 and 667 individuals m^-2, respectively. Polychaetes were the most dominant faunal group in species (96 species) and abundance (431 individuals m^-2). The major dominant species were the polychaetes Lumbrineris longifolia (76±224 individuals m^-2), Mediomastus californiensis (42±117 individuals m^-2), Tharyx sp.3 (26±110 individuals m^-2), the bivalvia Theora fragilis (54±78 individuals m^-2) and the amphipod Eriopisella schellensis (70±146 individuals m^-2). Based on the cluster and nMDS ordination analysis, macrobenthic communities were divided into three faunal groups. The first group was characterized by high abundance of the polychaeta Sternaspis scutata and the amphipod Ampelisca cyclops iyoensis, which is located by most stations of Hampyeong Bay and St. 4 of Deungnyang Bay. The second group was numerically dominated by the polychaeta Capitella capitata at St. 4 and St. 5 in Gamak Bay where was most pollutant area. Finally, the third group was dominated by the polychaetes Heteromastus filiformis, Tharyx sp.3 and the amphipod Sinocorophium sinensis. Therefore, geochemical characteristics such as the bay shape and pollution gradient may be important factors controlling of the macrobenthic community structure in Environment Conservation Area.

• The Korean Journal of Malacology
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• v.18 no.1
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• pp.41-52
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• 2002

This study was performed to know the vertical distribution pattern and community structure of intertidal invertebrates at 9 sampling stations near Songacksan area located in Jeju Island from June 2000 to May, 2001. A total of 104 benthic invertebrate species was recorded during the survey period and it was composed of 50 families, 25 orders, 12 classes and 6 phyla. Among them, the most highest species richness was observed in the mollusks comprising 66.3% (69 species) and the next one in the arthropods showing 16.3% (17 species). Species diversity was largely different depending on their vertical distribution, revealing much higher in the lower intertidal zone than in the middle or upper zone, while there were no distinct differences between sampling stations. The dominant species were Nodilittorina exigua, Littorina brevicula, Pollicipes mitella mitella and Nerita japonica in the upper zone, Monodonta neritoides, Lunella coronata coreensis and Nerita japonica in the middle zone and Notoacmea schrenckii, Omphalius nigerimus, Purpura clavigera and Chlorostoma argyrostoma lishckei in the lower zone. The macrobenthic fauna surveyed could be divided into two groups based on their species similarities between sampling stations but their differences were not distinctive.

• The Journal of Natural Sciences
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• v.10 no.1
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• pp.49-56
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• 1998

The survey of the macrobenthic animals near Hwasoo wharf, Inchon, Korea was carried out during October, 1995 through September, 1996. Polychaeta was the most dominant taxons were Mollusca and Crustacea. Only one species of Echinomermata, Protankyra bidentata, was collected. Capitella capitata collected from site 1 indicates that the site was more polluted, and Heteromasmus sp. collected from sites 2 and 3 suggests that these sites were polluted with organic materials.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.5
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• pp.635-648
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• 1995

Macrobenthic fauna were collected seasonally using the van Veen Grab $(0,1/m^2)$ to investigate the benthic faunal assemblages on the soft-bottoms around the Youngjong Island during October 1991 to July 1992. A total of 266 species was identified. Of these polychaetes comprised 111 species $(41.7\%)$; crustaceans $75(28.2\%)$ molluscs, $59 (22.2\%)$ and others including echinoderms, $27(7.9\%)$. Mean density and biomass were estimated to be 498 $ind./m^2$ and 54.8$g./m^2$, respectively. Polychaetes were the most dominant faunal group in terms of abundance $(332\;ind./m^2)$ and number of species as well, whereas echinoderms were predominant in biomass $(332\;g./m^2)$. The dominant species were Mediomastus sp., Heteromastus sp., Nipponomysella oblongata, and Nephts polyranchia; the abundance of these species showed seasonal variations. The study area was divided into three regions by cluster analysis based on the similarity of species composition. The first region consisted of intertidal flat (G-I); the second, shallow subtital region of muddy sand (G-II); the third, channel region of mud sediments (G-III). The intertidal flat showed the highest density, and the channel was the lowest density, but the Highest in species diversity. Distribution of macrobenthic faunal assemblages of the study area seemed to be controlled by sedimentary facies and duration of tidal exposure.

• Journal of the korean society of oceanography
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• v.33 no.1-2
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• pp.18-27
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• 1998

Based on 53 quantitative samples collected in April (23 stations) and August (30 stations) of 1993, the species composition, distribution and abundance of macrobenthic invertebrates and bottom characteristics in Chonsu Bay were conducted. Bottom sediments consisted of mud at the close to the dyke, sandymud in the central bay, and coarse sand in the mouth of the bay. A total of 273 species (177 species in April and 200 species in August) were identified. Mean density per sampling station was 480 ind./m$^2$ in April and 1126 ind./m$^2$ in August, respectively. Number of species and densities decreased in the northern part of the bay. The macrobenthos showed a temporal difference in species composition, range of distribution, and community delimitation caused by larval settling. Although during the settling period in summer, large numbers of juveniles added in most of regions, unrelated to environmental conditions, but, successful recruitment may has been a rare event locally Theora fragilis (bivalve), Lumbrineris longifolia(polychaete), Neptys oligobranchia (polychaete) were numerically dominant, but their densities varied seasonally. Community structures of macrobenthos in Chonsu Bay were affected by several bottom environmental conditions, related to tidal current speed, regionally.

• Ocean and Polar Research
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• v.44 no.2
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• pp.113-126
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• 2022

This study was carried out to investigate the benthic polychaetous community and benthic ecosystem quality status on the adjacent continental shelf of Jeju Island, and field surveys were conducted at 31 stations in July and August, 2020. The surface sediment was generally composed of muddy sand facies and sandy mud facies, and the average particle size was medium silt (6.1±1.6∅). The benthic polychaetous community revealed a total of 73 species with a mean density of 242 ind./m². The major dominant species were Notomastus latericeus, Ampharete arctica and Onuphis shirikishinaiensis. By the cluster analysis and nMDS results based on species composition of the benthic polychaetous community, the study area was divided into three station groups arranged from east to west by the water depth and sedimentary facies. The station group located in the west was subdivided into two station groups from south to north. From results of correlation analysis and PCA, it was found that the benthic polychaetous community in the study area had a strong correlation with the sedimentary environment and water depth. The benthic faunal community (or ecosystem) on the adjacent continental shelf of Jeju Island was assessed to be in a healthy state by biotic indices such as AMBI and BPI.