• Ocean and Polar Research
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• v.28 no.4
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• pp.369-383
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• 2006

The Saemangeum project is one of the biggest reclamation efforts in Korea and may cause coastal ecosystem change due to altered environments and habitat loss. Since February 2002, benthic environment and community structure in the Saemangeum studied area were studied to assess the influence of the project on macrofaunal community. The result of seasonal study from February, 2002 to August 2005 is reported here. Overall, changes of species numbers and dominant species of benthic animals in the periods before (1988) and after $(2002{\sim}2005)$ the Saemangeum dike construction were not evident both inside and outside the dike. However, local environmental and community change were noted The partial completion of Saemangeum dike $(4^{th}\;dike)$ in June 2003 altered water circulation and sediment deposition patterns both inside and outside the dike. Fine sediment was accumulated inside and outside the $4^{th}$ dike while coarse sediment dominated near the main channel (Sinsi gate). Benthic community resl)ended to the altered sediment type in these areas. Species number and diversity in both site was low compared to other sites. The dominant species in these areas were composed of the benthos that had not commonly occurred in the Saemangeum subtidal area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.882-895
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• 1997

Changes in the benthic communities have been studied to investigate the environmental effects before and after the construction of Shihwa Dike in the West coast of Korea. It is suggested that sequential changes in macrofaunal assemblages progressed in two sucressional directions. In the Shihwa lake under the influence of organic enrichment. First, the appearance of 'azoic tone' or 'grossly polluted zone' developed in the area of less than 6 m in depth resulted from the severe dissolved oxygen depletion due to the eutrophication from the increased organic loading. Second, the 'polluted zone' characterized by the proliferation of the opportunistic species in organically enriched area, was found in the vicinity of the industrial discharges and nearby fluvial inputs. This benthic community succession in the Shihwa lake seemed to be caused by the various ecological events such as an eutrophication in this organically enriched environment after construction of the dike and other physico-chemical parameters like salinity and dissolved oxygen in the bottom water, which may be influenced by the irregular surface water discharge and dilution by outer seawater inflow through the water gate of the dike. On the other hand, the benthic communities in the outside of the dike showed that the species richness was more than doubled and the abundance increased almost seven times more than that before the dike construction. This may be a typical characteristics of the initial phase in benthic eutrophication, suggesting that an increased organic input area may have been reponsible for this faunal change in the study area.

• Journal of the korean society of oceanography
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• v.31 no.1
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• pp.7-17
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• 1996

The species composition and distribution patterns of the subtidal benthic faunal assemblage in Sokmo and Yomha Channels and Kyonggi Bay were studied in spring and fall of 1989 and correlated to some environmental variables: temperature, salinity and substrate type. For both seasons, a total of 7,779 organisms were counted belonging to 244 species. Of these, 3,647 organisms in 185 species were counted for spring (March 1989) and 4,132 in 189 species for fall (September 1989). The oyster, Cressostrea gigas and the tellinidean bivalve, Moerella rutilla were the two most abundant species in the spring, constituting 17.22%and 6.47% of the total abundance respectively. While in the fall, the barnacle, Balanus reticulatus and macrura, Ogyrides orientalis dominated comprising 13.72% and 6.87 % of the total number of individuals. Community structure analysis revealed good correlations with the variations of salinity in Yomha and Sokmo Channels and sedimentary facies in Kyonggi Bay, Korea.

• Korean Journal of Environmental Biology
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• v.21 no.2
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• pp.101-113
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• 2003

The spatial distributional pattern of macrobenthic fauna was investigated to assess the summer benthic environmental conditions in Gwangyang Bay, the southern coast of Korea. The macrobenthic faunal community from 38 sites in Gwangyang Bay comprised 154 species and showed an overall mean density of 1,280 individuals $m^{-2}$. Polychaetes were the most important component of the macrofaunal community in species richness, abundance and biomass. The dominant species in abundance were polychaetes like Tharyx sp. (44.8%), Lumbrineris longifolia (14.0%), Heteromastus filiformis (3.6%), a mussel Mytilus edulis, and an amphipod crustacean Corophium sinense. The abundance and biomass in the western part of the bay were lower than those in the channel regions and mouth of the bay. The community indices showed the same trend in the spatial distribution with the abundance and species richness. All macrobenthic faunas were assigned into a specific functional group according to their ecological responses to the environmental stress. The benthic community health based on the Benthic Pollution Index (BPI) or Biotic Coefficient (BC) seemed to be in the normal to unbalanced er transitional condition, indicated by the dominance of small polychaete worms like Tharyx sp. in the mouth part of the bay.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.spc1
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• pp.203-213
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• 2006

The spatial patterns of meiobenthic communities in deep-sea sediment were examined. Sediment samples for analyzing of meiobenthic community structure were collected using a remote operated vehicle (ROV), multiple corer TV grab at 20 stations at five sites. In all, 15 meiofauna groups were recorded. Nematodes were the most abundant taxon. Benthic foraminiferans, harpacticoid copepods, polychaetes, and crustacean naupii were also dominant groups at all sites. The total meiofauna density at the study sites varied from 49 to 419 ind./$10cm^2$. The maximum density was recorded at a site located in Challenger Deep in the Mariana trench where simple benthic foraminifera with organic walls flourish. These distinctive taxa seem to be characteristic of the deepest ocean depths. Active hydrothermal sediments contain up to 150 harpacticoid copepods per $10cm^2$ of sediment. In a inactive ridge sediments, devoid of macrofaunal organisms:, the abundance of harpacticoid copepods never exceeded 15 ind./$10cm^2$. Multivariate analysis (multidimensional scaling) revealed significant differences in community structure among the three regions; near an active hydrothermal vent, in the deepest ocean depths and at typical deep-sea bed sites.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.6
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• pp.399-412
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• 2005

This study investigated the composition and the distribution of the benthic polychaeta community in the semi-enclosed Yoja Bay on the southern coast of Korea and was designed to deduce temporal changes in the community with the comparison of the previous studies. In YoJa Bay, benthic polychaetous community structure was investigated on the base of the samples from 87 stations. The surface sediment was mainly composed of fine-grained sediment, mixed clayey silt and silty clay. The total benthic macrofaunal density was $387 indiv./m^2$, and the density was higher in the middle bay, and in the mouth of bay than in the inner bay. scapharca subcrenata (Bivalvia) and amphipods (Crustacea) were important species in the inner and the middle of the bar, respectively. Benthic polychaetes were comprised of 72 species with a mean density of $149 indiv./m^2$. Their distributions showed higher densities in the mouth of bay than in the rest of bay. The dominant species over 1.0 percentages were composed of the 20 species, and they occupied $84.5\%$ of the total density. The most dominant species was Sternaspis scutata ($13.6\%$), fallowed fly Heteromastus filiformis ($9.8\%$), Polynoidae indet. ($8.3\%$), Sigambra tentacuzata ($7.1\%$) and others. The cluster analysis revealed that the study area was divided into three station groups. At the station group YI located in the inner bay, the most dominant species was Heteromastus filiformis . At the station group YII in the middle bay, the dominant species was Sternaspis scutata. And at the station group YIII in the mouth of bay, the dominant species was Paraiacydonia paradoxa. Whereas Sternaspis scutata and Mediomastus sp. were the dominant species in the past study, Heteromastus filiformis and Tharyx sp. appeared newly to be the dominant species, even if their low densities that in the past. These facts mean that Yoja Bay be maintained yet as little polluted area compared to other bays on the coast of Korea, but needed some caution of marine environmental management.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.3
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• pp.190-200
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• 2001

An ecological study was performed to investigate the community structure of the benthic macrofaunal assemblage on the Cheokjeon tidal flat, Incheon, Korea. Benthic samples were collected between Sept. 1990 and July1992 at three stations to compare environmental factors with the structure of benthic community among station sand seasons. Overall, macrofauna comprised a total of 111 species, and the mean density (708.1 md./$m^2$) and biomass (214.9gWWt/$m^2$). The number of species and individuals of polychaetes, molluscs and crustaceans made up more than 80% of the total number. On the other hand, in terms of biomass, bivalves and holothuroideans indicated that they were the dominant faunal groups. Hierarchical classification using the Bray-Curtis coefficient categorized samples into 3 station and 4 faunal groups. In terms of q-mode, there consisted of upper, middle and low tidal flat stations, respectively. And four faunistic groups were established as follows: 1) Heteromastus filifomis-Mactra veneriformis-Solen strictus-Ilyoplax finggi (wide-ranging elevation specialists), 2)Nephtys chemulpoensis-Macrophthalmus gaponicus (high elevation specialists), 3) Glycera subaenea-Decorifer matusimana-Tritodynamia (middle elevation specialists) and 4) Nephtys polybranchia-Borniopsis tsurumaru-Asthenognathus inaequipes-Protankyra bidentata (low elevation Specialists).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.1
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• pp.31-41
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• 1997

This study was carried out to investigate the composition and the distribution of the benthic community in the coastal area of Inchon seasonally from May 1994 to February 1995, and to estimate the environmental factors that effect the temporal and the spatial changes of benthic species composition. In the present study, 231 species were collected with the average density of 455 ind./$m^2$. The dominant species were Heteromastus sp., Sternaspis scutata, Chaetozone setosa, Mediomastus sp., Glycinde sp., Glycera sp. and Nephtys oligobranchia, which are in the polychaete group; abundance of these species showed seasonal and spatial variations. The study area was divided into 4 regions by cluster analysis such as outside area of Palmido (I), main channel region and adjacent are of Shihwa sea wall (II), north-eastern area of Youngjongdo (III), and the Inchon harbor and the mouth area of Sorae harbor (IV). The particle size of sediment which generally influences the distribution of the benthic community, the differences of the concentration of heavy metals, and of the dissolved oxygen, the increase of the proportion of polychaetes and molluscs, the absence of the crustacean phoxocephalids, and the increase of the abundance of pollution indicator species, indicated that the environment of the areas have been degrading gradually from Group I to Group IV.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.1
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• pp.9-23
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• 2007

To investigate the degree of pollution using the species composition of benthic community and environments, the present study was conducted in Jinhae Bay, May of 1998. In Jinhae Bay, benthic macrofaunal community was investigated on the base of the samples from 67 stations. The main facies of the surface sediment was silty clay and clay. The total species number and the mean density of macrobenthic animals were 255 species and 984 $ind./m^2$, respectively. There were 90 species and 773 $ind./m^2$ of polychaetes as the most major faunal group in Jinhae Bay. At the region between the eastern mouth of Jinhae Bay and Gadeok Is., the species number and density were higher, while lower at the western area of Jinhae Bay. The most dominant benthic macrofauna in Jinhae Bay was the polychaetes, Lumbrineris longifolia(16.9%), and followed by polychaetes Tharyx sp.(6.7%), Clone teres(4.7%), Glycinde sp.(4.2%), bivalves Theora fragilis(4.0%), crustaceans Corophium sp.(4.0%) and so on. The most of the predominant species appeared mainly on the region between the eastern mouth of Jinhae Bay and Gadeok Is. Cluster analysis based on the macrobenthic faunal composition showed that Jinhae Bay could be divided into three station groups: The western Jinhae Bay(Station group A), the mouth of Jinhae Bay(Station groupe B), and offshore area between Gadeok Is. and Geoje Is.(Station group C). The mouth of Jinhae Bay had the highest mean species number and the mean density, and its important species was Lumbrineris longifolia. The offshore area between Gadeok Is. and Geoje Is. had medium mean species number and the mean density. The western Jinhae Bay had the lowest mean species number and the mean density. The distribution of BPI and BC values, used to assess benthic pollution, showed similar patterns. According to the classification proposed by Borja et al.(2000), the stations of the western inner-bay were heavily polluted sites, the stations between mouth of the bay and the offshore area were slightly polluted sites, and the stations of the other area were meanly polluted sites. Benthic community healthiness of the western Jinhae Bay was classified to 'Transitional to pollution' by BC values. The degree of pollution in Jinhae Bay may have extended gradually from the western Jinhae Bay to the mouth of the bay.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.1
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• pp.20-31
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• 2002

This study was carried out to investigate the composition and the distribution of the benthic polychaetous communities in Deugryang Bay, semi-enclosed bays, on the southern coast of Korea and to deduce temporal changes in community with the comparison of the past studies. In Deugryang Bay, benthic polychaetous community structure was investigated on the base of the samples from 98 stations in 1996 and 1997. The main facies of surface sediment was clayey silt. The overall benthic macrofaunal density was 871 ind./m$^{2}$. The density was highest in the middle part of the bay because Musculus senhousia (Bivalvia) and cumaceans (Crustacea) had their highest densities in some stations. Benthic polychaetes were comprised of 100 species with a mean density of 138 ind./m$^{2}$. Their abundances were higher in the inner bay, in the middle bay, and in the mouth of bay, but poor community structures were established in the whole bay. The dominant species over 1.0 percentage were composed of the total 21 species, and they occupied 78.3% of the total abundance of the benthic polychaetes. The most dominant species was Lumbrineris longifolia (9.3%), followed by Eteone longa (7.3%), Heteromastus filifomis (7.1%), Sternaspis scutata (6.1%). From the cluster analysis, the study area could be divided into three station groups. Station group AI was located in the inner bay and in the shallow coastal region, and its most dominant species was Heteromastus filiformis. At the station group AII in the mouth of bay and in some channel region, its most dominant species were Lumbrineris longifolia and Eteone longa. And at the station group B located in middle part of the bay, the most dominant specis was Sternaspis scutata. In comparison with previous studies, the benthic polychaetous community experienced great change in the view of species number, density and dominant species. The dominant species were Sternaspis scutata and Eteone longa, but their densities declined greatly. Instead of these species, Lumbrineris longifolia and Heteromastus filiformis, known as the potential organic enrichment indicator species, appeared to the new dominant species even if their low densities. These facts mean that Deugryang Bay was maintained yet as little organic enriched area compared to other bays on the coast of Korea, but needed some caution of marine environmental management.