• Korean Chemical Engineering Research
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• 제51권1호
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• pp.106-110
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• 2013

거대 해조류인 다시마의 가수분해에 적합한 이온성 액체를 선정하기 위하여 20종의 이온성 액체를 실험에 사용하였다. 이 중 환원당의 생성능이 우수하다고 판단되는 3종의 이온성 액체 촉매(1-ethyl-3-methylimidazolium tetrafluoroborate, n-butyl-4-methylpyridinium tetrafluoroborate, n-methylmorpholine [$HSO_4$])를 선정하였다. 이들 이온성 액체를 대상으로 반응온도, 촉매량, 반응시간에 따른 영향을 조사하였다. 3종의 이온성 액체 촉매 모두에서 반응온도가 $121^{\circ}C$가 되어야 다시마의 가수분해가 일어나는 것으로 확인되었다. 3종의 모든 이온성 액체 촉매에서 반응시간이 지남에 따라 선형적으로 증가되는 경향을 보였다. 1-Ethyl-3-methylimidazolium tetrafluoroborate를 촉매로 사용한 경우에서는 90분에는 약 6.2 g/L, n-butyl-4-methylpyridinium tetrafluoroborate는 6.4 g/L, n-methylmorpholine [$HSO_4$]는 6.0 g/L의 환원당을 얻을 수 있었다. 이로부터 이온성 액체를 촉매로 이용하여 해조류로부터 당의 생산가능성을 확인하였다.

• ALGAE
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• 제30권2호
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• pp.139-146
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• 2015

Urchin barrens have been a major issue of rocky coastal ecosystems in temperate regions. In South Korea, the east coast and Jeju Island have especially been a focus because the area of barren ground increases in spite of continual efforts to install artificial reefs. This study approached the urchin barrens issue in South Korea, by focusing on a correlational analysis of urchin and macroalgal abundance. Urchin density and algal species coverage were obtained using a quadrat image analysis. Subtidal sites were then classified into three groups according to the average densities of urchins to evaluate the characterization of the macroalgal community: no urchin (NU) zone; transition (TR) zone, $4inds.\;m^{-2};$ and urchin (UR) zone, ${\geq}8inds.\;m^{-2}$. The average urchin density in the study site was $4.7inds.\;m^{-2}$ and 57 macroalgal species were found in the study site. From the NU zone to UR zone, total species number, species diversity index and evenness gradually decreased, whereas the dominance index increased. The algae species with negative correlations were Grateloupia divaricata, Polysiphonia morrowii, Chondracanthus intermedius, Delesseria violacea, Desmarestia viridis; and those with positive correlations were the crustose corallines, Sargassum horneri. Other species were not significantly correlated with urchin density. The significant correlations indicate that the abundance of some macroalgal species is proportionally regulated by sea urchin density. This study also shows how macroalgal vegetation changes in response to an urchin's density gradient in a natural condition; and there is a TR zone that existed with respect to an intermediate level of algal abundance.

• ALGAE
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• 제22권1호
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• pp.37-44
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• 2007

In order to understand the impact of the heavy-oil pollution by the 1997 Nakhodka oil spill on the intertidal macroalgal vegetation, we have been monitoring succession in the intertidal flora since 1997 at Oh-ura, Takno, and Imago-Ura Cove, Kasumi in Hyogo Prefecture, northwestern coast of Honshu, Japan. We employed two different monitoring methods: 1) The percent cover of macro-algae (seaweeds) in 1 x 1 m quadrats along 450 m intertidal transects parallel to the shoreline were assessed and recorded by photographic imaging until 2002, and for 30-40 m transects of the most heavily polluted areas in 2004 and 2006; 2) The percent cover of macro-algae in 0.5 x 0.5 m quadrats along a transect line perpendicular to the shore were recorded and all macrophytes within the quadrat were completely removed to record the wet weight of each taxon (1997-2006). Based on the monitoring data, we conclude that the high intertidal zone at Imago-ura, where a large part of the stranded oil accumulated, suffered the heaviest damage and experienced the slowest recovery. In addition, although the original status of macroalgal vegetation before the impact was not well-documented, it appeared that recovery from the damage caused by the oil pollution required four to five years.

• ALGAE
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• 제32권4호
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• pp.325-336
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• 2017

Intertidal community recovery and resilience were investigated with quantitative and qualitative perspectives as a function of disturbance timing. The study was conducted in a lower intertidal rock bed of the southern coast of South Korea. Six replicates of artificial disturbance of a $50cm{\times}50cm$ area were made by clearing all visible organisms on the rocky substrate in four seasons. Each of the seasonally cleared plots was monitored until the percent cover data reached the control plot level. There was a significant difference among disturbance timing during the recovery process in terms of speed and community components. After disturbances occurred, Ulva pertusa selectively preoccupied empty spaces quickly (in 2-4 months) and strongly (50-90%) in all plots except for the summer plots where non-Ulva species dominated throughout the recovery period. U. pertusa acted as a very important biological variable that determined the quantitative and qualitative recovery capability of a community. The qualitative recovery of communities was rapid in summer plots where U. pertusa did not recruit and the community recovery rate was the lowest in winter plots where U. pertusa was highly recruited with a long duration of distribution. In this study, U. pertusa was a pioneer species while being a dominant species and acted as a clearly negative element in the process of qualitative recovery after disturbance. However, the negative effect of U. pertusa did not occur in summer plots, indicating that disturbance timing should be considered as a parameter in understanding intertidal community resilience in temperate regions with four distinct seasons.

• Journal of the korean society of oceanography
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• 제35권1호
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• pp.56-64
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• 2000

The importance of terrestrial organic matter as a food source for a brackish water clam Corbicula japonica was evaluated using stable carbon isotope ratios (${\delta}^{13}$C) in its tissues and potential food resources in an estuarine system of Youngil Bay, Korea. Suspended particulate organic matter (POM) had distinct ${\delta}^{13}$C values from riverine (-31.8 to -27.2%$_o$) to marine waters (-21.0 to -16.6%$_o$). Estuarine macroalgae had a wide ${\delta}^{13}$C range of -22.8 to -15.0%$_o$. The ${\delta}^{13}$C values of riverine POM were more negative than that of riverine phytoplankton (-26.5 to -24.2%$_o$) but similar to that of freshmarsh plant species (-29.1 to -27.5%$_o$ for Phragmites communis and -28.5 to -27.0%$_o$ for Salix gracilistyla), These ${\delta}^{13}$C values suggest that the POM transported by the Hyungsan River is predominantly of terrestrial origin rather than riverine autochthonous sources. The ${\delta}^{13}$C values of Corbicula japonica tissues (-28.7 to -27.2%$_o$) were most similar to values for riverine POM and freshmarsh plants. There was no significant difference in the isotopic composition of the clam individuals. The results indicate a predominant contribution of organic carbon derived from terrestrial and fresmarsh plant detritus to the diet of Corbicula japonica. Our results also confirm previous suggestion that terrestrial organic matter can be incorporated into estuarine food webs although its role is confined to the upper estuarine reaches.

• 한국수산과학회지
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• 제48권6호
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• pp.969-976
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• 2015

Macroalgal community structure was seasonally examined at Hakampo (Taean) in western coast of Korea from February 2007 to October 2010. Also, the effects of "Hebei Spirit" oil spill on the seaweed community structure were evaluated. A total of 101 macroalgal species were identified, comprising 12 green, 18 brown and 71 red algae. Species richness ranged 58-65 species with maximal in 2008 and minimal in 2009. Seaweed biomass ranged $75.81-102.06g\;dry\;wt./m^2$ (mean, $88.78g/m^2$) with maximal in 2008 and minimal in 2010. Vertical distribution from the high to low intertidal zone was Neorhodomela aculeata and Polyopes affinis; Corallina pilulifera and Chondrus ocellatus; Sargassum thunbergii and Ulva australis. Coarsely-branched seaweeds comprised the highest proportion of biomass ($37.17g/m^2$, or 41.86% of the total biomass) and ecological state group I (ESG I) seaweed biomass was between 81.67-85.44%. Also, ephemeral macroalgae including Ulva species sharply increased in species number and biomass within 1-2 year from the "Hebei Sprit" oil spill in the mid and low intertidal zone. Hakampo rocky shore is still good condition as evaluated based on macroalgal species number, biomass, and composition in functional form and ESG I seaweeds.

• 한국수산과학회지
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• 제51권3호
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• pp.262-277
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• 2018

We seasonally examined marine macroalgal community structures and ocean environmental characteristics in subtidal zones at five sites on and around Jeju Island, Korea, from February 2013 to November 2015. A total of 186 macroalgal species were identified, including 18 green, 33 brown, and 135 red algae. During the study period, the number of species was highest at Gapado Island (125 species) followed by Bukchon (123 species), Sagye (122 species), Sinheung (122 species) and Sinchang (97 species). Ecklonia cava, Peyssonnelia caulifera, Synarthrophyton chejuense, Corallina aberrans and Corallina crassisima occurred at all study sites and in all seasons. The average annual biomass of seaweed was $1,125.10g\;wet\;wt./m^2$ and ranged from $899.77g/m^2$ at Sinheung to $1,452.00g/m^2$ at Gapado. A brown alga E. cava was the most dominant species, accounting for 49.84% ($560.78g/m^2$) of the total seaweed biomass. Subdominant species were C. aberrans and C. crassissima, comprising 6.83% ($76.79g/m^2$) and 5.98% ($67.28g/m^2$) of total biomass, respectively. Cluster analysis revealed three distinct groups: the Sagye/Sinheung group (group A), the Bukchon/Sinchang group (group B), and the Gapado group (group C), indicating significantdifferences in macroalgal communities between sites.

• Korean Chemical Engineering Research
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• 제58권2호
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• pp.293-300
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• 2020

홍조류인 Eucheuma spinosum은 카라기난을 주된 다당으로 함유하고 있으며 Indonesia, Malaysia, Philippines, China, Tanzania 등지에서 상업적으로 생산되고 있다. 본 연구에서는 E. spinosum을 대상으로 FeCl₃-촉매 수열반응을 통하여 당과화학중간체(5-HMF, levulinic acid, formic acid)로전환하고자하였다. 통계적실험법(3-수준-3-인자의 Box-Behnken design)을 적용하여 반응인자(반응온도, 촉매농도, 반응시간)의 최적화와 영향을 평가하였다. 최적화 결과, 5-HMF의 농도는 160 ℃, 0.4 M FeCl₃, 10 min에서 2.96 g/L가 생성되었다. Levulinic acid와 formic acid의 최적 조건은 200 ℃, 0.6 M FeCl₃, 30 min으로 결정되었고, 농도는 각각 4.26 g/L와 3.77 g/L이었다.

• Ocean and Polar Research
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• 제37권4호
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• pp.317-325
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• 2015

To evaluate the relative ecological quality of Taean coastal areas in terms of various seaweed community indices, seasonal samplings were taken at the Hakampo, Padori, Chaeseokpo, Mongsanpo and Bangpo shores from March 2006 to January 2007. A total of 105 species were identified; species richness ranged from 37~72 species spatially and from 65~75 species seasonally over the study period. Coarsely-branched seaweeds were dominant in functional group and ESG I (ecological state group I) made up 61 species (58.10%) of the identified macroalgae. The average seaweed biomass at the five study sites was $56.63g\;dry\;wt./m^2$ (range, 36.66 at Hakampo $-73.89g/m^2$ at Mongsanpo). Seaweeds were generally abundant in mid and low intertidal zone. Corallina pilulifera, Ulva australis, Sargassum thunbergii, Neorhodomela aculeata, and Symphyocladia latiuscula were the dominant species across all five study sites. Species diversity was between 1.24~2.30, while species evenness was between 0.40 and 0.61. The dominance index ranged from 0.43 at Padori to 0.64 at Mongsanpo. Given the community indices and shore descriptions, the five study sites were divided into two groups based on ecological quality: moderate (Chaeseokpo and Mongsanpo) and good (Hakampo, Padori and Bangpo).

• 미생물학회지
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• 제44권2호
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• pp.116-121
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• 2008

Haloperoxidase를 생산하는 미생물을 분리하기 위하여 국내 연근해와 남북극 등의 해양시료에서 분리된 방선균 균주를 대상으로 탐색을 수행하여 남해 백도 해조류 추출물로부터 분리된 한 종류의 방선균(#1460)에서 높은 haloperoxidase 활성이 확인되었다. 본 균주의 생리.생화학적 특성은 Streptomyces 속과 유사하며 생산되는 haloperoxidase는 세포 조 추출물로부터 ammonium sulfate precipitation, High-Q column chromatography, gel permeation chromatography, Hydroxyapetite chromatography 그리고 hydrophobic interaction chromatography를 통하여 42%의 수율과 purification fold 70으로 정제하였다. 본 효소의 최적 반응 pH는 7이고 pH 8에서 더 높은 안정성을 보여 $60^{\circ}C$에서 1시간 반응에 효소활성의 50%가 생존한다. 또 cyanide와 azide 이온에 의해 강한 저해현상을 보인다.