• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.6
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• pp.694-707
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• 2016

This study investigated the community structure of macrobenthic assemblages in the Taehwa River Estuary, Ulsan, Korea. Macrobenthos were collected with a Van Veen Grab Sampler during February and November 2012. The total species number and mean density were $176species/9.6m^2$ and $1,992inds./m^2$, respectively. Polychaetes were the most dominant faunal group in terms of species (91 species) and abundance ($1,463inds./m^2$). The major dominant species were polychaetes Minuspio japonica ($609{\pm}1,221inds./m^2$), Hediste japonica ($174{\pm}318inds./m^2$), Tharyx sp.1 ($106{\pm}283inds/m^2$), Lumbrineris longifolia ($79{\pm}207inds./m^2$), bivalve Theora fragilis ($114{\pm}272inds./m^2$) and amphipod Grandidierella japonica ($88{\pm}223inds./m^2$). Based on community statistics (cluster analysis and non-metric multidimensional scaling (nMDS) ordination), the macrobenthic community was divided into three station groups. Group I(freshwater dominated stations 2-6 with coarse sediment) was characterized by a high abundance of polychaetes Minuspio japonica, Hediste japonica, Capitella capitata, Pseudopolydora kempi, amphipods Grandidierella japonica and Apocorophium acutum. Group II (ecotone, stations 7-9 with mixed sediment) was numerically dominated by bivalve Theora fragilis, polychaetes Cirriformia tentaculata, Tharyx sp.1, Lumbrineris longifolia and Chaetozone sp. Finally, Group III (seawater dominated stations 10-12 with fine sediment) was characterized by a high density of polychaete Magelona japonica. These results showed that changes in salinity gradient and sedimentary characteristics were the main factors behind spatial changes in the macrobenthic communities of the Taehwa River Estuary.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.4
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• pp.213-228
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• 2009

This study was conducted to investigate spatio-temporal changes in macrobenthic community structure and benthic environmental conditions in Geoje-Hansa Bay, which is the greatest oyster producing site in Korea. Field survey for benthic environment and macrobenthos was seasonally carried out at 15 stations covering oyster farming sites and non-farming sites from February to November, 2008. The grain size of surface sediments was dominated by very fine silt with the mean phi of about $9\;{\Phi}$ and TOC was 1.9% on average. Mean dissolved oxygen content was 8.1 mg/L and lowest in August corresponding to the 2nd degree in seawater quality criteria. Total species number was 351 and mean density was $3,675\;ind./m^2$, both of which were dominated by polychaete worms. Spatio-temporal variation in above two biological variables was great with higher values seasonally in spring and spatially in channels rather than inner bay. Dominant species were Lumbrineris longifolia (21.3%), Aphelochaeta monilaris (17.8%) and Ericthonius pugnax(6.1%), all of which are typical species of organically enriched area. From the multivariate analyses, the whole macrobenthic community was distinguished into two groups of channel and inner bay group. Spatio-temporal changes of macrobenthic community in Geoje-Hansan Bay were related to those of TOC and acid volatile sulfide (AVS). Our results showed that Geoje-Hansan Bay should be intermediately affected by organic pollution, and that such organic enrichment was more remarkable at farming stations in the inner bay.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.225-237
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• 2001

The community structure of macrobenthos was investigated around Sorido Island, southern coast of Korea between August 1996 and April 1997. Triplicate macrobenthic samples were taken seasonally at twelve stations in August and November 1996 and fourteen stations in February and April 19n by van Veen grab ($0.1m^2$). A total of 217 macrobenthic species were identified during study Period: 80 species were from polychaetes, 60 species from crustaceans, and 46 species from mollusks. The mean density of macrobenthos estimated $1,068 ind/m^2$, and polychaetes comprised $85\%$ of total density. The mean biomass was $110.2 g/m^2$, and echinoderms contributed to more than a half of the biomass. Major dominant species based on abundance were three polychaetes Tharyx sp., Lumbrineris longifolia, and Magelona japonica, which frequently occur in the coastal area enriched by organic pollution. The densities of the species were $582 ind/m^2$, $72 ind/m^2$, and $41 ind/m^2$, respectively. These species showed very low density in the offshore area. The study area was classified into four regions each sustaining specific macrofaunal assemblages by Bray-Curtis cluster analysis: a station group adjacent to the Kwangyang Bay and Yosu harbour and three station groups around Sorido Island. There were negative correlations between the concentration of PAHs in sediments and the abundance of Ampeliscidae spp. and Amphipoda. These results were discussed in terms of both environmental factors and distribution of benthic community.

• 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.

• 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.

• Ocean and Polar Research
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• v.38 no.2
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• pp.115-128
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• 2016

This study examined the relationship between macrobenthic distribution patterns and environmental factors in salt marsh vegetation in Donggeomdo, Ganghwa on the west coast of Korea. Nine stations were fixed on a transect across the salt marsh vegetation, and field sampling was carried out monthly from July 1997 to June 1998. A total of 38 species of macrobenthos were recorded: each of faunal groups, 13 (34.2%) Arthropoda, 12 (31.6%) Polychaeta, 8 (21.1%) Mollusca, and 5 (13.2%) others. The mean density was $2,659individuals/m^2$, with a mean biomass of $178.6gWWt/m^2$. Mollusca dominated in terms of abundance and biomass, with a mean density of $2,172individuals/m^2$ (81.7%) and a mean biomass of $131.9gWWt/m^2$ (73.9%). The number of species decreased in winter (January-February), while mean density increased in the spring (May-June). The biomass was relatively in Summer and Fall (July-November), than any other season. The number of species was high in pure stands of Suaeda japonica in the lower salt marsh vegetation, and the mean density and biomass were high in mixed halophyte communities in the middle salt marsh vegetation. Two Mollusca, the bivalve Glauconome chinensis and gastropod Assiminea lutea, were dominant. The densities of these two species were high in mixed halophyte communities in the middle salt marsh vegetation. Non-metric multi-dimensional scaling (nMDS) showed that the study area could be divided into four groups corresponding to the vertical distribution of tidal levels and halophytes. Spearman's rank correlation revealed that the distribution patterns and community structure of macrobenthos were related to environment variables such as salinity of the substrates, exposure time, and grain size compositions of the sediment in the salt marsh vegetation. Particularly, the distribution and density of some dominant species showed differences along the vertical distributions of halophytes.

• 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.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.4
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• pp.272-286
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• 2014

This study was performed to investigate the community structure and health assessment of macrobenthic assemblages in Cheonsu Bay, West Coast of Korea. Total species number was 224 and mean density was $1,940ind./m^2$, both of which were dominated by polychaete worms (111 species and $1,213ind./m^2$). In terms of density, the major dominant species were the bivalve Theora fragilis ($280{\pm}213ind./m^2$), the polychaetes Heteromastus filiformis ($254{\pm}218ind./m^2$), Lumbrineris longifolia ($216{\pm}41ind./m^2$), Mediomastus californiensis ($158{\pm}97ind./m^2$) and the amphipod Eriopisella sechellensis ($167{\pm}100ind./m^2$). As a result of community statistics (cluster analysis and nMDS ordination), the macrobenthic community structure was classified two major groups (inner and mouth of bay) and two stations (station 2 near Ganwol dyke in spring and summer). The Benthic Pollution Index (BPI) and AZTI's Marine Biotic Index (AMBI) were applied to assess the benthic ecological status. During the sampling periods, the BPI Index values varied between 11 (bad status) and 92 (high status). On the other hand, the AMBI Index values was ranged between 1.34 (good status) and 4.39 (poor status). In conclusion, in terms of the mean BPI and AMBI Index values, the ecological status of Cheonsu Bay were moderate status (ecotone stage) and good status, respectively.