• ALGAE
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• v.22 no.3
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• pp.209-219
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• 2007

Marine algal flora and community structure of medicinal seaweeds were examined at Kkotji of Taean Peninsula, Korea from May 2005 to January 2006. Seventy-nine seaweeds including 42 medicinal algae and one marine plant were identified. Sargassum thunbergii was the representative alga occurred at all seasons and shore levels. The dominant medicinal seaweeds were perennial S. thunbergii, Neorhodomela aculeata, and Corallina pilulifera, and ephemeral Monostroma grevillei, Porphyra yezoensis, and Ulva pertusa. Their vertical distribution were N. aculeata – P. yezoensis, M. grevillei, and U. pertusa – C. pilulifera from high to low intertidal zone. The average biomass of medicinal seaweeds varied from 34.17 g m–2 in spring to 56.41 g m–2 in summer. At Kkotji shore, the opportunistic species (Enteromorpha, Ulva, and Cladophora) and turf-forming algae (Caulacanthus okamurae and Gelidium divaricatum) were easily observed. Such fast growing ESG II (ecological state group) was 87.50% and slow growing perennial algae, ESG I was only 12.15%. Also, diversity index (H’) and dominance index (DI) indicate that the seaweed community of Kkotji is unstable. Therefore, Kkotji rocky shore should be more protected from human activities such as turbulence and eutrophication in order to maintain species diversity and abundance of medicinal seaweeds.

• Korean Journal of Ecology and Environment
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• v.41 no.2
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• pp.137-143
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• 2008

The abundance and community structure of epilithic diatoms grown on different substrata were investigated in two first-order streams located in a limestone and granite area, north of the Suzuka Mountains in Central Japan. Experiments were conducted as follows: limestone and granite without algae were submerged in their own streambed or another stream station and incubated for seven weeks, while limestone and granite with algae were transferred to another stream station and incubated at the same time. The diatom biomass was consistently high in the lime-stone station experiments compared to those at the granite station. In addition, there was more diatom biomass on granite substrata than on the limestone substrata at both stations. The present results suggested that the difference in water chemistry including the major nutrient concentrations was the limiting factor for algal growth in these two streams; however, when the water chemistry was the same in each stream, the difference in substratum characteristics became the important factor affecting the diatom abundance. The diatom community grown on the transferred substrata with and without algae became similar to those grown on the original substrata in each stream during the incubation period. It was suggested that the effect of the substrata characteristics on the diatom community structure was rather small.

• Ocean and Polar Research
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• v.32 no.3
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• pp.321-329
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• 2010

Photosynthetic pigments, nutrients, and hydrographic variables were examined in order to elucidate the spatio-temporal variation of water column structure and its effect on phytoplankton community structure in the western channel of the Korea Strait in fall 2006 and spring 2007. High phytoplankton biomass in the spring was associated with high salinity, implying that nutrients were not supplied by coastal waters or the Yangtze-River Diluted water (YRDW) with low salinity. Expansion of the Korea Strait Bottom Cold Water (KSBCW) and a cold eddy observed during the spring season might enhance the nutrient supply from the subsurface layer to the euphotic zone. Chemotaxonomic examination showed that diatoms accounted for 60-70% of total biomass, followed by dinoflagellates. Nutrient supply by physical phenomena such as the expansion of the KSBCW and the occurrence of a cold eddy appears to be the controlling factors of phytoplankton community composition in the Korea Strait. Further study is needed to elucidate the mechanisms by which the KSBCW is expanded, and its role in phytoplankton dynamics.

• Ocean and Polar Research
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• v.42 no.4
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• pp.271-281
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• 2020

We investigated mesozooplankton in the Yellow Sea in spring to understand its community structure and relationship with environmental factors. Total mesozooplankton density ranged from 1,542 to 7,367 ind. m-3 and the biomass ranged from 3 to 42 mg C m-3. The total density and biomass had a positive relationship with chlorophyll-a (chl-a) concentration. The mesozooplankton community was divided into two groups at 125.5 E by cluster analysis: one was an inshore group and the other was an offshore group. The inshore group of mesozooplankton was of high density but low diversity, while the offshore group was of high diversity but low density. Copepod Acartia hongi and its copepodites were the most abundant species, comprising 27.8% of the total mesozooplankton density. A. hongi was especially abundant at the inshore, serving as the indicator species of the inshore group. Redundancy analysis found a positive relationship between the density of A. hongi and chl-a concentration. Oithona similis and Centropages abdominalis were 2nd and 3rd dominant species comprising 9 and 7% of the total density, respectively. The density of O. similis was positively related to water depth, but C. abdominalis was related to chl-a concentration. Chl-a concentration seems to influence significantly the mesozooplankton community structure in the Yellow Sea in spring, rather than water temperature or salinity.

• Journal of the Korean Institute of Gas
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• v.19 no.2
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• pp.74-82
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• 2015

Carbon dioxide was designated as one of greenhouse gases that cause global warming. Among various ways to solve the $CO_2$ emission issue, the 3rd-generation biomass (algae) production is considered as a viable method to reduce $CO_2$ in the atmosphere. In this research, we propose a design of an innovative sustainable production system by utilizing the 3rd generation biomass in the environment of floating production storage and offloading (FPSO). Existing biomass production systems depend on the solar energy and they cannot continue producing biomass at night. Electricity produced from offshore wind farms also need an efficient way to store the energy through energy storage system (ESS) or deliver it real-time through power grid, both requiring heavy investment of capital. Thus, we design an offshore grid structure harnessing LED lights to supply the necessary light energy, by using the electricity produced from the wind farm, resulting in the maximized production of biomass and efficient use of wind farm energy. The final design integrates the biomass production system enhanced by LED lights with a wind power generation. The suggested NLP model for the optimal design, implemented in GAMS, would be useful for designing improved offshore biomass production systems combined with the wind farm.

• Journal of Ecology and Environment
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• v.36 no.4
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• pp.223-233
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• 2013

Acid deposition is one of the most serious environmental problems in ecosystems. The present study surveyed the effects of simulated acid rain on leaf litter mass loss and microbial community in the decomposing leaf litter of Sorbus anifolia in a microcosm at $23^{\circ}C$ and 40% humidity. Microbial biomass was measured by substrate-induced respiration (SIR) and phospholipid fatty acids (PLFAs), and the microbial community structures were determined by composition of PLFAs at each interval of decomposition in litter sample and at each pH treatment. The microbial biomass showed peaks at mid-stage of decomposition, decreasing at the late stage. The leaf litter mass loss of S. anifolia decreased with decreasing pH during early and mid-decomposition stages; however the mass loss becomes similar between pH treatments at late-decomposition stage. The acidification remarkably lowers the microbial biomass of bacteria and fungi; however, microbial diversity was unchanged between pH treatments at each stage of litter decomposition. With changes of decomposition stage and pH treatment there were considerable differences in replacement and compensation of microbial species. Fungi/bacteria ratio was considerably changed by pH treatment. The PLFA profile showed significantly larger fungi/bacteria ratio at pH 5 than pH 3 at the early stage of decomposition, and the difference becomes smaller at the later decomposition stage. At low pH, pH 3 and pH 4, the fungi/bacteria ratios were stable according to the litter decomposition stages. Simulated acid rain caused decreases of 10Me17:0, 16:1${\omega}$7c, 18:1${\omega}$7, 15:0, but increase of 24:0. In addition, litter mass loss showed significant positive correlation with microbial biomass measured by SIR and PLFA on the decomposing leaf litter.

• The Korean Journal of Ecology
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• v.20 no.5
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• pp.355-365
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• 1997

Macrozoobenthic community structure was studied on the mud-tidalflat around Mokpo coastal area, Korea, from September 1995 to May 1996. Ten sampling stations were chosen along the 1km transect with a 100 m intervals. Triple macrozoobenthos sampling were conducted with a stainless box core sampler (size $13{\times}22{\times}30$ cm) at each station on the seasonal basis. A total of 119 species of macrobenthos was sampled with a mean density 2,357 $ind./m^2$ and biomass of 180. 94 $g/m^2$ during the study period. Of these species, there were 51 species of mollusce (43%), 36 of crustaceans (30%), 27 of polychaetes (23%). Molluscs were density-dominant faunal group with a mean density of 1,804 $ind./m^2$, comprising of 75% of the total density of the benthic animals. It was followed by polychaetes with 347 $ind./m^2$ (15% of the total density). Molluscs were biomass-dominant faunal group with a mean biomass of 147.51 $g/m^2$ (82% of the total biomass). The number of species, abundance and biomass showed increasing trends toward the lower intertidal stations from the higher stations. Major dominant species were Musculista senhousia (bivalve), Capitellidae spp. (polychaetes) with a density of 1,640 $ind./m^2$ and 179 $ind./m^2$ , respectively. The density of M. senhousia was more than 63% of the total density of benthic organism on the tidal area. Small gastropod Cerithideopsilla umumriensis was another dominant epifaunal species between st.1 and 2 with a mean density of 100 $ind./m^2$. Cluster analysis showed that the benthic community could be divided into three stational groups, that is, upper, middle and lower groups by the exposure duration.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.4
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• pp.372-385
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• 2016

This present study investigated characteristics of distribution and community structure of macrobenthic invertebrates through the survey of commercial Danish seine fisheries from 2011 to 2013. In this study, a total of 28 species were sampled with a mean density of $32,568ind./km^2$ and mean biomass of $1,649.5kg/km^2$. The dominant species, comprising over 1.0% of the total number of individuals, were Chionoecetes opilio ($11,203ind./km^2$, 34.4%), Pandalus eous ($9,247ind./km^2$, 28.4%), Ophiuridae spp. ($5,750ind./km^2$, 17.7%), Argis lar ($2,631ind./km^2$, 8.1%), Neocrangon communis ($994ind./km^2$, 3.1%), Berryteuthis magister ($612ind./km^2$, 1.9%), Sepiola birostrata ($499ind./km^2$, 1.5%) and Strongylocentrotidae sp. ($424ind./km^2$, 1.3%). The dominant species, in terms of biomass, comprising over 1.0% of the total biomass, were C. opilio ($1,167.2kg/km^2$, 70.8%), B. magister ($130.3kg/km^2$, 7.9%), P. eous ($102.4kg/km^2$, 6.2%), Ophiuridae spp. ($84.6kg/km^2$, 5.1%), Enteroctopus dofleini ($45.5kg/km^2$, 2.8%), A. lar ($35.7kg/km^2$, 2.2%), Strongylocentrotidae sp. ($25.0kg/km^2$, 1.5%) and S. birostrata ($22.1kg/km^2$, 1.3%). Among them, S. birostrata, E. dofleini, Strongylocentrotidae sp. and Ophiuridae spp. were higher abundance and biomass in the shallow water (<200 meters in depth), whereas C. opilio, P. eous, A. lar, N. communis and B. magister were higher in the deep water (301 ~ 500 meters in depth). As the results of cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on the Bray-Curtis similarity of fourth root transformed data for number of species and individuals, the macrobenthic invertebrates community by Danish seine survey was divided into two groups of station in the shallow water (<200 meters in depth, Group A) and the deep water (201 ~ 500 meters in depth, Group B). The major individual-dominant species was S. birostrata, Ophiuridae spp. and immature C. opilio in group A. But Group B was P. eous, A. lar, B. magister and mature C. opilio.

• Korean Journal of Ichthyology
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• v.31 no.2
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• pp.90-100
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• 2019

This study was carried out from March to November, 2013 to investigate the fish community structure and distribution characteristics of Phoxinus phoxinus and Rhynchocypris kumgangensis appearing in Gihwacheon Stream, Pyeongchang. A total of 6 families and 19 species of fish emerged during the survey period. The dominant species were R. kumgangensis (Individuals 44.7%, Biomass 30.2%) and P. phoxinus (Individuals 27.7%, Biomass 15.9%). Endemic species were 10 species including Pseudopungtungia tenuicorpus, Coreoleuciscus splendidus, Hemibarbus mylodon, Gobiobotia brevibarba, Microphysogobio longidorsalis, R. kumgangensis, Zacco koreanus, Korecobitis rotundicaudata, Iksookimis koreensis and Coreoperca herzi. Endogenous species were P. tenuicorpus, G. brevibarba and P. phoxinus. Hemibarbus mylodon was a natural monument. Oncherhynchus mykiss was exotic species and translocated species was Oncorhynchus masou masou. The dominant species, R. kumgangensis, appeared at all survey sites. Except for St.6, the b value was more than 3.0 and the slope of K value showed positive correlation. P. phoxinus appeared in St. 3~St. 6 and St. 3 and St. 4 only showed stable populations.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.935-944
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• 2014

To elucidate the variation of species composition, biomass and size distribution of fishery resource in the Uljin marine ranching area was investigated at the 4 stations from 2009 to 2010 based on the dredge sampling. During the survey period, a total of 41 fishery resource species were sampled with a mean density of $2,554,633\;ind./km^2$ and mean biomass was $32,946kg/km^2$. A total 36 fishery resource species were sampled with a mean density of $3,198,793\;ind./km^2$ and mean biomass $41,177kg/km^2$ in 2009 and it were sampled a total 31 species, mean $1,910,473kg/km^2$ and $24,716kg/km^2$ in 2010. The major individual-dominant species, occupying over 1% of total individuals, were Gomphina veneriformis (2,491,818 ind., 82.2%), Umbonium costatum (221,973 ind., 8.7%), Mactra chinensis (49,879 ind., 2.0%), Glossaulax didyma hayashii (49,879 ind., 1.9%), Blepharipoda liberate (37,714 ind., 1.5%) and Paguridae spp. (27,266 ind., 1.1%). The major biomass-dominant species, occupying over 1% of total biomass, were G. veneriformis (25,124 kg, 76.3%), G. didyma hayashii (2,596 kg, 7.9%), M. chinensis (2,024 kg, 6.1%), Ovalipes punctatus (921 kg, 2.8%) and Glossaulax didyma didyma (567 kg, 1.7%). From the cluster analysis based on Bray-Curtis similarity matrix of fourth root transformed data of species number and individuals was divided into 2 different groups of the fishery resource community (Group A-St.1, Group B-Sts. 2, 3, 4). The 2009 and 2010 mean Shell length (mm) of G. veneriformis was 37.73 mm, 29.76 mm and M. chinensis was 62.03 mm, 44.94 mm, respectively.