• 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.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.

• 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.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.1
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• pp.8-19
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• 2002

Spatial distribution pattern of macrozoobenthos was studied along the salinity gradient and sedimentary environment in the Watancheon estuary, Beobseongpo, southwest coast of Korea. Ten stations were set from the mouth towards the head of estuary. Three replicate sediment samples were taken using a van Veen grab (surface area $0.1m^{2}$) at each station between June 1998 and January 1999. A total of 114 species were collected during the study period and they are composed of 44 species of polychaetes (39%), 34 of crustaceans (30%), 24 of molluscs (21%) and 12 of miscellaneous. The former two taxa together accounted for 69% in the total number of species. The mean density was 3,053 ind./m$^{2}$, comprising 2,536 ind./m$^{2}$ from polychaetes (83%) and 439 ind./m$^{2}$, crustaceans (14%). Moreover, the mean biomass was 58.23 gwwt./m$^{2}$, consisting of 29.56 gwwt./m$^{2}$ from polychaetes (51%), 23.38 gwwt./m$^{2}$, molluscs (40%). A spionid polychaete Minuspio japonica, two corophiid amphipods Grandidierella japonica and Corophium sinense, a bivalve Potamocorbula amurensis were major dominants at the head of estuary where the salinity was relatively lower compared with contiguous sites. The distributions of M. japonica and G. japonica were significantly related to the salinity and sediment environment, respectively, whereas C. sinense and P, amurensis showed no significance. The nereid polychaete, Hediste japonica, also predominated at the head of the estuary where bottom salinity was relatively low. Species diversity was high at the mouth area whereas low diversity and few species number were seen at the stations in the head of the estuary, influenced by freshwater and sandy sediment. Based on the cluster analysis, the macrobenthic community was classified into four station groups from head (station group A) toward mouth (group D) in the study area. The number of species and abundance between station group B and C were significantly different. And the abundance of between two neighboring station groups (station group A and B, B and C, C and D) was also different. These results suggested that the spatial distribution pattern of macrobenthos in this estuary seemed mainly related to gradients in bottom salinity and sediment grain size among environmental factors.

• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.341-352
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• 2009

This study was carried out to investigated community structure of macrobenthic assemblages around the Wolseong Nuclear Power Plant, East Sea of Korea and seasonal sampling was performed from October 2007 to July 2008. A total of 163 macrobenthic fauna were collected. The overall average macrobenthos density and biomass were 1,005 individuals $m^{-2}$ and $21.81\;gWWt\;m^{-2}$, respectively. Based on the LeBris (1988) index, there were 10 dominant species accounting for approximately 69.00% of total individuals. The major dominant species were the polychaetes Spiophanes bombyx (349 inds. $m^{-2}$), Mediomastus californiensis (82 inds. $m^{-2}$), Sigambra tentaculata (55 inds. $m^{-2}$), Magelona japonica (50 inds. $m^{-2}$), Scoletoma longifolia (33 inds. $m^{-2}$) and the Unidentified amphipod (Amphipoda spp., 72 inds. $m^{-2}$). 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 major station groups. The major group 1 was associated with sand dominated stations and was characterized by high abundance of the bivalves Mactra chinensis, Siliqua pulchella and the polychaete Protodorvillea egena. On the other hand, major group 2 was connected with mud dominated stations and was numerically dominated by the polychaetes M. californiensis, M. japonica, Sternaspis scutata, S. longifolia and the bivalves Thyasira tokunagai and Theora fragilis. However, macrobenthic community structure were no significant differences between the environmental variables (sediment type and depth) and heated discharge.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.2
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• pp.97-105
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• 2011

This study investigated the community structure and spatio-temporal variation of macrobenthic assemblages around Gijang Province, East Sea of Korea. Macrobenthos collected seasonally using a modified van Veen grab sampler from March to November 2006. A total of 157 macrobenthic fauna were collected. The overall average macrobenthos density were $552 \;ind/m^2$. The species number of macrobenthos was in the range from 62 in winter and spring to 122 in autumn. On the other hand, abundance fluctuated between 6,540 (in spring) and 17,920 (in autumn) inds./$18m^2$. Cluster analysis and non-metric multi-dimensional scaling (nMDS) were applied to assess the spatio-temporal fluctuation in the macrobenthic assemblages. Cluster analysis and nMDS ordination analysis based on the Bray-Curtis similarity identified 3 station groups. The group 1 (station 8~10, 12, 13, 17 and 18) was characterized by high abundance of the polychaete Lumbrineris longifolia, the bivalve Ennucula tenuis and the Amphipoda spp., with mean phi range from $6.2{\Phi}$ to $7.1{\Phi}$ (above 50m water depth). The group 2 (station 5~7, 11, 14~16) was numerically dominated by the po1ychaete Ampharete arctica and the bivalve Theorafragilis (mean phi: $6.0{\sim}7.0{\Phi}$; within 40 m water depth). Finally group 3 (station 1~4) was characterized by high density of the polychaetes Magelona japonica and Sternaspis scutata, with mean phi range from $3.5{\Phi}$ to $6.9{\Phi}$ (below 30 m water depth). In conclusion, the Macrobenthic community structure showed a distinct spatial and temporal trend, which seemed to be related to the water depth and sediment composition.

• Korean Journal of Environmental Biology
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• v.32 no.4
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• pp.286-296
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• 2014

In this study, we investigated the macrobenthic community structure and spatiotemporal variations in Uljin Marine Ranching area, East Sea of Korea. Macrobenthos were collected using a modified van Veen grab sampler from April to September 2013. Total number of species sampled was 345 and mean density was 5,797 ind. $m^{-2}$, both of which were dominated by the polychaetes. The most dominant species were Spiophanes bombyx (53.64%), followed by Magelona sp.1 (6.96%), Cadella semitorta (2.73%), Lumbrineris longifolia (2.16%) and Alvenius ojianus (2.08%). Cluster analysis and nMDS ordination analysis based on the Bray-Curtis similarity identified 2 station groups. The group 1 (station 2, 3, 5, 6, 8 and 9) was characterized by high abundance of the polychaetes Magelona sp.1, Lumbrineris longifolia, Scoloplos armiger, Praxillella affinis, Maldane cristata and the bivalve Alvenius ojianus, with fine sediment above 30m water depth. On the other hand, the group 2 (station 1, 4, 7 and 10) was numerically dominated by the polychaete Lumbrineriopsis sp. and the bivalve Cadella semitorta, with coarse sediment below 5m water depth. Collectively, the macrobenthic community structure showed a distinct spatial trend, which seemed to be related to the water depth and sediment composition.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.2
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• pp.76-86
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• 2012

Macrozoobenthos were collected from 24 sites using small grab ($0.05m^2$) in order to see the spatial distribution of them at Sueocheon stream at the northern part of Gwangyang Bay during summer season when the maximum ecological processes are occurring. A total of 44 species of macrozoobenthos occurred, and their mean density was $789individuals/m^2$. Mollusks was the dominant faunal group accounted for 43.1% and 86.8% of the whole community density and biomass, respectively. Top five dominant species were a molluscan, Corbicula japonica (40.7%), two polychaete worms, Neanthes japonica (19.3%) and Heteromastus filiformis( 8.1%), and two crustaceans, Paranthura japonica (6.9%) and Jaeropsis sp. (6.9%). Species diversity index was very low with mean value of 1.12 and maximum value was recorded at the river mouth. At the upper stream, a brackish water species such as Corbicula japonica showed their maximum population density. The overall distribution of stream macrobenthos showed a rather simple pattern along with salinity and grain size gradients with few brackish water species occurring at coarse sediments in the stream but more diverse faunas inhabiting fine sediments in the river mouth.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.3
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• pp.139-146
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• 2011

In order to detect the early impacts of the Hebei Spirit oil spill on the subtidal macrozoobenthos, we conducted a benthic survey at 72 stations in the subtidal area of Tae-an, the eastern Yellow Sea from Dec. 18th 2007 to Dec. 22th after 10 days from the Hebei Spirit oil spill. A total of228 species from 72 stations was sampled with mean density of 561 ind $m^{-2}$ and mean biomass of 39.7 gww $m^{-2}$. In this study, Ampelisca occurred as a major dominant fauna in this survey, but did not appear around oil spill areas. Meanwhile some opportunistic polychaete worms like Prionospio bocki, Prionospio cirrifera appeared in the oil spill area, especially near coastal beaches. The overall abundance and biomass of macrozoobenthos decreased after oil spill. However some stations previously disturbed with sand extraction showed a similar macrozoobenthic community structure.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.4
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• pp.256-264
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• 2014

This study was carried out to estimate the benthic environments and polychaetous community in Garolim Bay, through five field surveys from April 2006 to April 2007. Garilim Bay is a semi-enclosed bay and composed of a biramous tidal channel and nearby wide tidal flats. Surface sediment in the inner bay was composed of fine grained particles whereas that in the mouth area of bay was of coarse grained ones. Benthic polychaete worms were the most dominant taxa occupying 65.1% of total benthic macrofauna. Species number was higher in the inner bay than mouth and outer area of bay, and in the bay higher on the tidal flat than channel area. Density was higher on the tidal flat than channel area. Dominant polychaetous species were Prionospio sp., Heteromastus filiformis, Lumbrineris longifolia and so on, which is known as opportunistic species. Prionospio sp. and H. filiformis inhabited mainly on the tidal flats in inner bay, while L. longifolia in the channel area and mouth of the bay. Cluster analysis and nMDS showed the typical inner-to-outward distribution of station groups, which indicated the sequential difference of the species composition of each station group. To assess the benthic healthiness of Garolim Bay by AMBI and BPI analysis, the benthic condition was analyzed from slightly polluted in the outer and mouth of the bay to moderately polluted in the inner bay. Assumed from dominant species composition and benthic healthiness condition, benthic environments of Garolim Bay was slightly unstable and disturbed and organic enrichment was currently underway by massed fisheries farms.