• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.4
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• pp.297-309
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• 2016

This study was carried out to investigate the differences in sedimentary environments and benthic polychaete communities between farming grounds and natural habitats (non-farming ground) in Gamak Bay. Sampling stations of natural habitats were evenly distributed in the entire bay. And mussel farm, oyster farm and ark-shell farm were selected as farming grounds. Dominant sedimentary facies was mud in most sampling stations of farming grounds and natural habitats. However organic contents were higher in the farming grounds than natural habitats of the bay. The species number and mean density of polychaetous community in the natural habitats were greater than those from the farming grounds. Lumbrineris longifolia, known as potential organic enrichment indicator species, was first dominant species both in farming grounds and natural habitats of the bay. However, the next dominant species consisted of different species between two benthic habitats. As a result of community analysis using cluster analysis and nMDS, the natural habitats were divided into several station groups, but most of stations in farming grounds were clustered into one group. Pearson' correlation analysis and PCA showed high relationships between sedimentary environmental factors and benthic polychaetous community in natural habitats, but low or no relationships in farming grounds. That means benthic polychaetous community established in farming ground was under unusual condition such as high input of organic matter. Thus it is necessary to improve the benthic environmental quality of the farming grounds as well as the north-western inner part in Gamak Bay through long-term monitoring efforts.

• Journal of Life Science
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• v.19 no.12
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• pp.1758-1763
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• 2009

Biological assessments of benthic macroinvertebrates community structure were carried out in ten reservoir inflow and outflow areas of the Nakdong river system from April 2008 to August 2008. The collected benthic macroinvertebrates from the surveyed sites were 9,427.6 inds./$m^2$, 42 species belonging to 29 families and 16 orders. A dominant species was Chironomus sp. and a subdominant species was Ecdyonurus levis. In the all sites, Ephemeroptera had the most number of species (17.81%) and Diptera had the most number of individuals (64.00%). Dominance, species diversity, species richness, and species evenness indexes were 0.68, 2.42, 2.96 and 0.54, respectively. The numbers of benthic macroinvertebrates species in each surveyed site were from 21 (site 9 Jilnal wetland) to 51 (site 2 Yeongcheon reservoir). As a result of an analysis about relative resistance and resilience of stability factors, the most popular group was group I with high indices in both resistance and resilience. Site 7 (Beongae wetland) and site 8 (Jangcheok reservoir) had the highest similarity in the result of cluster analysis using the surveyed benthic macroinvertebrates.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.3
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• pp.157-164
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• 2009

In order to rehabilitate habitats for marine organisms in the slag dumping area, succession of benthic communities was monitored on artificial seaweed beds with transplantation of Ecklonia stolonifera from April 2004 to June 2005. Acinetospora critina was only primary dominated on steel frame in the first experiment (April 2004). A total of 15 species of seaweed were identified in the second experiment (June 2004). Enteromorpha intestinalis and Enteromorpha sp. were dominated, and Urospora penicilliformis, Ulothrix flacca, Cladophora sp., and Ulva pertusa were found on Ecklonia stolonifera fronds gradually with increasing time. This time was coincided with occurrence of benthic macrofaunas, molluscans and small fish species. The epiphytic benthic macrofaunas were dominated on amphipods, molluscans were Mytilus edulis, Thais clavigera, and fish species were Mugil cephalus, Pholis nebulosa. These results indicated that transplantation of Ecklonia stolonifera on artificial seaweed beds have been contributed on restoration habitats for benthic communities in the slag dumping area.

• Journal of the Korean earth science society
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• v.30 no.4
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• pp.409-426
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• 2009

In the four sedimentary cores from Yeoja Bay, the analyses of grain size, benthic foraminiferal species compositions, assemblages and statistics were carried out to investigate the effects of late Holocene sea-level change on benthic foraminifera. The core sediments were mainly composed of fine-grained silt and clay. The benthic foraminifera were classified into 27 species of 16 genera, 30 species of 21 genera, 50 species of 29 genera and 52 species of 29 genera in Core YC-1 to 4, respectively. In the result of cluster analysis, it seemed that Group 1 (Core YC-1 and 2) of representative A. beccarii assemblages was deposited in upper bay environment and Group 2 (Core YC-3 and 4) of representative E. clavatum-A. beccarii assemblages was deposited in inner bay environment affected by offshore water. In the result of species composition analysis, the production frequency of A. beccarii was gradually decreased from low layer to upper layer, whereas production frequency of E. clavatum and P.F./T.F. was gradually increased to upward. These change patterns appeared in benthic and planktonic foraminifera seemed to reflect the late Holocene sea-level rise in Yeoja Bay.

• Korean Journal of Environment and Ecology
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• v.29 no.5
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• pp.743-752
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• 2015

We studied the spatio-temporal microalgal (phytoplankton and benthic diatoms) and environmental changes of the Hajeonri intertidal zone from February to November 2014. Seawater and phytoplankton analysis were conducted all through the months. The species, composition and abundance of phytoplankton and environmental factors were measured. As a result, diatom was dominant among a total of 113 species identified. On a seasonal basis (Feb. May, Aug., Nov.), we carried out studies on benthic diatoms on the surface of the sediments and their habitats at nine stations on the transect line at Hajeonri at low tide. The grain of the surface sediments was mainly composed of sandy silt and sandy mud. Organic pollution level was low. Benthic microalgal biomass (chlorophyll ${\alpha}$) was high in the spring and summer. A total of 163 benthic diatom species were identified. Navicula sp.1 and Paralia sulcata were dominant over the study period. Five diatom species were observed both in water column and on surface sediment at the same time.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.107-116
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• 2018

In this study, the distribution of sedimentary environment and benthic macro-fauna in habitats and non-habitats of Zostera marina were investigated. The purpose of this study was to obtain basic data about the sedimentary environment and benthic macro-fauna in the habitats and non-habitats of Z. marina. Sand was dominant within habitat environments, whereas the non-habitats were predominantly composed of silt. As a result, the habitats of Z. marina have a different grain size and organic matter content compared to the non-habitats. These differences in the sedimentary environment were expected to influence the species composition of benthic animals. Benthic communities in the habitats of Z. marina showed a higher density and a greater number of species than in the non-habitats. As a result of an ecological index evaluation, the species diversity index (H') was $3.44{\pm}0.10$ for the habitat; the non-habitat was analyzed as $2.34{\pm}0.35$. It was also found that the stability of community in the habitats was higher than that in the non-habitats. The cluster analysis also clearly showed that habitats and non-habitats of Z. marina have distinct characteristics.

• Korean Journal of Ecology and Environment
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• v.50 no.3
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• pp.275-285
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• 2017

To investigate the changes of dominant species of benthic macroinvertebrates according to the changes of temperature and precipitation, we surveyed twenty sites of the main Seomjin River in May and September in 2013 and 2014. The temperature, precipitation, water quality factors and substrate composition, which are important factors in benthos habitat environment, were collected and measured. The average temperature of the Seomjin River increased by $0.2^{\circ}C$ in 2014 compared to 2013, and the temperature increased from upstream to downstream, showing a difference of more than $3^{\circ}C$. Also, the annual cumulative precipitation (ACP) was increased toward low latitude. The temperature of Seomjin River increased more than twice in September ($21.7{\sim}24.5^{\circ}C$) after rainfall compared to May ($7.6{\sim}11.3^{\circ}C$) before rainfall, and CP (cumulative precipitation) increased about 3 times before rainfall (263 mm~287.5 mm) and after rainfall (756.3 mm~882 mm). Due to washing effect by summer precipitation, total number of species and individuals for benthic macroinvertebrates were higher in May than in September. Chironomidae sp. and Choroterpes altioculus were dominated in May, Ecdyonurus levis, Macrostemum radiatum and Choroterpes altioculus were dominated in September. As a result of correlation analysis between community indices and environment factors, it was found that there is a high correlation with boulder and sand among substrate compositions. According to the results of cluster analysis based on temperature, CP and the dominant species of benthic macroinvertebrates in Seomjin River, it was divided into two groups following temperature and CP, and the dominant species and geographical position were reflected and divided into detailed groups.

• Journal of Environmental Impact Assessment
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• v.30 no.4
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• pp.203-214
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• 2021

Assessment of benthic quality status was implemented along the subtidal areas of Jindo and Jejudo to understand faunal structure of polychaete assemblages and ecological quality of the benthic environment. Sediment analysis was characterized by well sorted of both mud and sand in Jindo, and a little higher sand in Jejudo instead. A total of 68 polychaete species were found at 14 sampling stations with a mean density of 231 inds./m², and 61 species, 167 inds./m² and 62 species, 295 inds./m² in Jindo areas and Jejudo areas. Dominant species found in Jindo areas were Heteromastus filiformis, Ampharete arctica, Prionospio sp., Sigambra tentaculata, Thelepus sp. and Amphicteis gunneri, Ampharete arctica, Prionospio sp., Spiochaetopterus costarum, Heteromastus filiformis in Jejudo. With a help of cluster analysis, it was found that the sampling stations showed distinctive pattern of the distribution pattern and benthic quality status in Jindo and Jejudo except sampling station numbers 5 and 6, respectively. AMBI analysis the results were 1.2-3.4, grade V benthic polychaetes did not appear. It was evident that both Jindo and Jejudo had different sedimentary characteristics as well as distribution pattern of polychaete assemblages.

• Korean Journal of Environmental Biology
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• v.40 no.2
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• pp.172-186
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• 2022

Benthic macroinvertebrates are important ecological and environmental indicators as primary or secondary consumers, and therefore are widely used in the evaluation of aquatic environments. However, there are no comprehensive river ecosystem monitoring surveys that link the major physicochemical water quality items with benthic macroinvertebrates in urban streams. Therefore, this study investigated the distribution characteristics of benthic macroinvertebrates and physicochemical water quality items (17 items) in Yangjaecheon and Yeouicheon from 2019 to 2020. At the same time, by applying Spearman's rank correlation analysis and nonmetric multidimensional scaling (nMDS) analysis in the water quality data and biotic index, we tried to provide basic data for diagnosing the current status of river ecosystems in major urban rivers in Seoul. Based on the study results, a total of 39 species and 3,787 individuals were identified in Yangjaecheon, the water quality(based on BOD, TOC, and TP) of Yangjaecheon was higher than Grade Ib(good), and the BMI using benthic macroinvertebrates appeared as Grade C(normal) at all the sites. In Yeouicheon, a total of 51 species and 4,199 individuals were identified, the water quality(based on BOD, TOC, TP) was higher than Grade Ib(good) similar to Yangjaecheon, and the BMI of both Upstream and Saewon bridge was Grade B(good), while Yeoui bridge was Grade C(normal). Overall, analysis results for the distribution of benthic macroinvertebrates by a nonmetric multidimensional scaling method showed no significant difference between the two streams (p=0.1491). Also, significant environmental variables related to benthic macroinvertebrates distribution were determined as water temperature and DO. On the other hand, the results of the correlation analysis between biotic index and major water quality items confirmed that R1 and BMI could be used for on-site urban river water quality evaluation.

• Korean Journal of Ecology and Environment
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• v.43 no.4
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• pp.477-491
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• 2010

Benthic macroinvertebrates were collected two times from 116 sites at the $1^{st}{\sim}4^{th}$ order streams in forest areas in Gyungsang province in late spring and late summer. The sample sites belonged to slightly and moderately polluted states. When communities were classified by the Self-Organizing Map (SOM), the gradient was observed according to degree of pollution. Within clusters of slightly polluted sites, however, seasonality was further observed. Scrapers, gatherer-collectors, and filterer-collectors were abundantly observed in late spring while shredders appeared more in late summer. The number of predator species increased in late summer. Behavior types were mostly clingers in two seasons. Community compositions at the moderately polluted sites were not much differentiated in different seasons. Gatherer-collectors and burrowers were dominantly collected in both seasons.