• Korean Journal of Environmental Biology
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• v.32 no.1
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• pp.35-48
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• 2014

In order to estimate the effect of additional nutrients on phytoplankton growth and horizontal phytoplankton community distribution during the autumn season in 2010 and 2011, we investigated the abiotic and biotic factors of surface and bottom waters at 20 stations of inner and offshore areas in Gwangyang Bay, Korea. Also, nutrient additional experiments were conducted to assess additional nutrient effects on phytoplankton assemblage using the surface water. In both years, the total nutrients were high at the enclosed inner bay and the mouth of Seomjin River, whereas it was low at the St.15~20 where in influenced by the surface warm water current from offshore of the bay. On the other hand, nano- and pico-sized Chl. a were gradually increased towards the outer bay and their trends were significant in 2011 than in 2010. The cryptophyta species occupied more than 85% of total phytoplankton assembleges in 2010, whereas their abundance in 2011 remainds to be 1/10 levels of 2010. Following the cryptophata species, the diatom Chaetoceros spp. and Skeletonema-like spp. were found to be dominant species. Further the biosaasy experimental results shows that the phytoplankton biomass in the +N and +NP treatments was higher compared to control and +P treatments and its trend was significant at St.8 and St.20 where nutrient concentration were low. Based on the bioassay and field survey, providing the high nutrients may have stimulated to phytoplankton growth such as S. costatum-like spp.. In particular, opportunistic micro-algae such as Cryptomonas spp. were able to achieve the high biomass under the relatively mid nutrient condition from bottom after break down of seasonal stratification in the Gwangyang Bay.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.4
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• pp.189-197
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• 1977

In present study, the effects of various factors including the solvent concentration, extraction time and temperature, the ratio of sample vs extraction solvent, (w/v) and pH upon the extractability of the NaCl and alcohol soluble proteins of marine algae were investigated. Eight species of fresh algae, the major ones in consumption as food, namely Porphyra suborbiculata, Undarie pinnatifida, Hizikia fusiforme, Sargassum, fulvellum, Enteromorpha linza, Sargassum kjellmanianum, Codium coarctatum, and Ulva pertusa were used for the extraction of NaCl soluble protein and dried materials of four species, Perphyra suborbiculata, Undaria pinnatifida, Enteromorpha linza and Sargassum fulvellum were used for the extraction of alcohol soluble protein. The frozen and mascerated samples were prepared by the same method described in previous paper (Ryu, 1977). And the dried materials were moistened with alcohol solution before freezing. The effect of solvent concentration on the extractability of NaCl soluble protein differed from species. The extractability of Undaria Pinnatifide, Hizikia fusiforme, Perphyra suborbiculata, Enteromorpha linza, and Ulva pertusa reached maxima at 0.25M NaCl solution while the 1.0M for Sargassum fulvellum, Saygassum kjellmanianum and Codium coarctatum. In case of alcohol soluble proteins, it was shown at $20\%$ ethanol solution for Porphyra suborbiculata, Undaria pinnatifida, Enteromorpha linza, and Sargassum fulvellum. Variation of the ratio of sample vs solvent gave slight effect upon the extractability, but the ratio of 1:30(w/v) seemed most efficient for the extraction of NaCl soluble proteins and 100 ml solvent added to 1 g dried sample was effective in case of alcohol soluble proteins. Extraction time has a minimal effect upon the extraction of alcohol soluble protein, and approximately 21 to $43\%$ of algal protein was extracted within 1 hour. But in case of NaCl soluble protein extraction, the effect of time revealed differently from species to species resulting in that the extraction for 1 hour gave a maximum extractability in Ulva pertusa and Enteromorpha linza, 2 hours in Porphyra suborbiculata, Codium coarctatum and 3 hours in Undaria pinnatifica, Hizikia susiforme, Sargassum fulvellum and Sargassum kjellmanianum. When the NaCl soluble protein of Undaria pinnatifida and Enteromopha linza was extracted at various temperature, the most effective extraction temperature was $40^{\circ}C$ while the temperature was $50^{\circ}C$ for Undaria pinnatifida and $60^{\circ}C$ for Hixikia fusiforme, Sargassum fulvellum, Sargassum kjellmanianum and Codium coarctatum. Bus in case of alcohol soluble extraction, the optimum temperature was $30^{\circ}C$ for Enteromorpha linza and $40^{\circ}C$ for Undaria pinnatifida, Sargassum fulvellum and Porphyra suborbiculata. In the effect of pH on extractability, the maximum extractability of NaCl soluble proteins was obtained at pH 7to 8 and pH 8 to 9 for alcohol soluble protein.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.4
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• pp.401-410
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• 2003

Three beaches of the Seogwang-ri coast in the western part of Wu Island, Jeju-do, are solely composed of rhodoliths (red algal nodules). The beach sediments are coarse sand to granule in size and they show the banded distribution according to size. Commonly the larger pebble-sized rhodoliths are concentrated near the rocky coast, resulting from the transportation of the nodules from shallow marine environments by intermittent typhoons. Based on the internal texture of the rhodoliths, it appears that crustose red algae, Lithophyllum sp., is the main contributor for the formation of the rhodolith. The coarse sand to granule-sized grains show that they started to grow from the nucleus as rhodoliths, but the surface was severely eroded by waves. However, the pebble to cobble-sized grains exhibit the complete growth pattern of rhodoliths and sometimes contain other calcareous skeletons. It is common that encrusting red algae are intergrown with encrusting bryozoan. The surface morphology of rhodolith tends to change from the concentric to domal shape towards the outer part. This suggests that the rhodolith grew to a certain stage by rolling, but it grew in more quiet condition without rolling as it became larger. Aragonite and calcite cements can be found in the pores within rhodoliths (conceptacle, intraskeletal pore in bryozoan, and boring), and this means that shallow marine cementation has occurred during their growth. Growth of numerous rhodoliths in shallow marine environment near the Seogwang-ri coast indicates that this area has suitable oceanographic conditions for their growth such as warm water temperature (about 19$^{\circ}C$ in average) and clear water condition due to the lack of terrestrial input of volcanoclastic sediments. Fast tidal current and high wave energy in the shallow water setting can provide suitable conditions enough for their rolling and growth. Typhoons passing this area every summer also influence on the growth of rhodoliths.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.271-275
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• 1999

The chemical and gelling properties of porphyran from Porphra yezoensis collected from Buan and Wido in Korea at different months of the year were studied. Crude porphyran was prepared by hot-water extraction and further purified by cetylpyridinium chloride precipitation, Crude porphyran and porphyran were modified by alkali treatment to eliminate sulfate. The yields of alkali-modified crude porphyran (AMCP) and porphyran(AMP) were between $4.9\~10.9\%$ and $4.0\~6.7\%$ of the dried algae weight and were maximum in February for Buan and January for Wido, respectively. Gel strength of AMCP were highest in February ($790g/cm^2$) for Buan and January ($740 g/cm^2$) for Wido. Alkali modification increased 3,6-anhydro galactose content and the molar ratio of galactose and 3,6-anhydrogalactose of AMCP and AMP showed 1 : 0,8$\~$1.1. GLC and FT-IR measurement of AMP showed that most of sulfate residues were combined to C-6 of galactose, Thus, results of this study suggest that crude porphyran extracted from Porphra yezoensis produces an agar of a reasonably good quality after alkali treatment.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.1-9
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• 1999

Numerous observations revealed strong evidence of increased middle ultraviolet radiation or UV-B (280 ~ 320 nm) at the earth's surface resulting from stratospheric ozone depletion. UV is the waveband of electromagnetic radiation which is strongly absorbed by nucleic acids and proteins, thus causing damage to living systems. It has been recorded in the East Sea, Korea that solar UV-B impinging on the ocean surface penetrates seawater to significant depths. Recent researches showed that exposure to UV-B for as short as 2h at the ambient level (2.0 Wm$^{-2}$) decreased macroalgal growth and photosynthesis and destroyed photosynthetic pigments. These may suggest that UV-B could be an important environmental factor to determine algal survival and distribution. Some adaptive mechanisms to protect macroalgae from UV-damage have been found, which include photoreactivation and formation of UV-absorbing pigments. Post-illumination of visible light mitigated UV-induced damage in laminarian young sporophytes with blue the most effective waveband. The existence of UV-B absorbing pigments has been recognized in the green alga, Ulva pertusa and the red alga, Pachymeniopsis sp., which is likely to exert protective function for photosynthetic pigments inside the thalli from UV-damage. Further studies are however needed to confirm that these mechanisms are of general occurrence in seaweeds. Macroalgae together with phytoplankton are the primary producers to incorporate about 100 Gt of carbons per year, and provide half of the total biomass on the earth. UV-driven reduction in macroalgal biomass, if any, would therefore cause deleterious effects on marine ecosystem. The ultimate impacts of increasing UV-B flux due to ozone destruction are still unknown, but the impression from UV studies made so far seems to highlight the importance of setting up long-term monitoring system for us to be able to predict and detect the onset of large -scale deterioration in aquatic ecosystem.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.40-48
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• 2016

This study mainly focused on isolation of marine algicidal bacteria associated with phytoplankton blooms and characterization of algicidal activity against harmful algae. Harmful algal blooms (HABs) found naturally in surface waters have caused many environmental problems worldwide. In this study, forty bacterial strains that have capability of inhibiting harmful algal growth were isolated from Masan Bay, Jinhae Bay, Dol Island, Jangmok Bay, and the Tongyeong Sea, Republic of Korea. The bacteria were screened furthermore for the characteristics on algicidal activities against Cochlodinium polykrikoides, Chattonella marina, Skeletonema costatum, Heterosigma akashiwo, Heterocapsa triquetra, Prorocentrum minimum, and Scrippsiella trochoidea. As a result, the algicidal bacteria that were screened from double over layer agar and microscopic counts tests belonged to genera Pseudomonas, Vibrio, Bacillus, Pseudoalteromonas, Ruegeria, Joostella, Marinomonas, Stakelama, Porphyrobacter, and Albirhodobacter. One of the most important HAB species is Co. polykrikoides and the strongest algicidal activity against the dinoflagellate was 94.00% after 6 h treatment with 10% bacterial culture filtrate. In this study, Marinomonas sp. M Jin 1-8, Stakelama sp. ZB Yeonmyeong 1-11 & 1-13, Porphyrobacter sp. M Yeonmyeong 2-22, and Albirhodobacter sp. 6-R Jin 6-1 were found to be as new genera of bacteria having anti-algal activity. These results suggest that these bacteria might play an important role in controlling phytoplankton blooms.

• Membrane Journal
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• v.25 no.2
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• pp.132-143
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• 2015

Water is an essential resource for humans, but fresh water becomes scarce due to population growth and contamination of limited resources. Membrane technology has been widely used for water treatment, and forward osmosis is a process which does not need high hydraulic pressure for the operation. However, there are needs for (1) development of novel draw solutes causing low internal concentration polarization and reverse salt flux for high water flux, and (2) development of economic recovery method of the draw solutes in the diluted draw solution. Previous researches on the draw solute include $NaHCO_3$ which can be regenerated by about $60^{\circ}C$ heating, sucrose which can make potable water without additional process, and magnetic nanoparticles which can be regenerated by external magnetic field. Using the principles of forward osmosis process, sea water desalination, wastewater treatment, refinement of proteins, energy generation using pressure retarded osmosis process, preparation of diluted fertilizer, and growing algae for biofuel can be conducted. This paper summarizes characteristics of ideal draw solutes, recovery method of the draw solutes, and various application examples.

• Korean Journal of Environment and Ecology
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• v.28 no.6
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• pp.613-626
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• 2014

Seaweeds were identified after qualitative sampling at 14 stations of Dokdo coasts from May to July 2013 and seaweeds and animals inhabiting 23 Eisenia bicyclis plants were examined to evaluate its ecological role. Biomass was calculated by using regression between stipe length and weight of E. bicyclis. A total of 128 species were identified, including 18 green, 35 brown, and 75 red algae. Coarsely branched form was dominant functional group occupying 47.66% and 91 species (71.09%) were in ESG I group, growing in stable environmental coast. Also, R/P, C/P, and (R+C)/P were 2.14, 0.51, and 2.66, respectively showing temperate and mixed flora. Biomass and density of E.bicyclis were $23.74kg\;m^{-2}$ and 64 fronds $m^{-2}$. Twelve seaweeds and 83 animal species (15 Annelida, 25 Mollusca, 34 Arthropoda, 3 Echinodermata, and 6 others) were observed from 23 holdfasts and Ericthonius pugnax was dominant taxon having 538 (43.11%) of 1,248 animal individuals. These results indicate that E.bicyclis is a keystone species showing very important ecological role. In conclusion, the number of seaweeds increased because of intensive research and dominance of coarsely branched form and ESG I group seaweeds, representing that environmental condition of Dokdo is still intact.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.21 no.3
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• pp.103-111
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• 2016

Seasonal dynamics of kelp forest-forming algae, Ecklonia cava population formed following the large-scale disturbance by Typhoon 'Bolaven' in August 2012 were investigated in Jeju Island, Korea. Morphological characteristics, recruits density, mortality rate, total density and biomass were monitored bimonthly from June 2013 to June 2015. Total and longest blade lengths, and individual weight of E. cava showed distinct seasonal trends. Stipe length increased from winter to spring, but did not show increase or reduced from summer to autumn. This indicates that morphological characteristics of E. cava are mainly affected by the change of blades. The optimal temperature for E. cava growth was about $15-18^{\circ}C$ during winter to spring while the growths were inhibited at the water temperature above $20^{\circ}C$ during summer. E. cava exhibited very low recruitment during spring-summer. However, high recruitment was observed on April 2015 when canopy cover was very low due to low density. This indicates that recruitment of E. cava was controlled not by seasonal effects but by physical factors such as canopy and space. The mortality rate of juvenile plants was highest due to their unstable settlement. By June 2015, 34 months after the disturbances, E. cava was almost recovered to the pre-disturbance population size structure. These results suggest that recovery of kelp forest following the large-scale disturbance requires a considerable period of time (more than three years). This study should provide valuable ecological information on management, restoration and protection of kelp species.

• Journal of dental hygiene science
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• v.15 no.6
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• pp.712-720
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• 2015

The purpose of this study is to examine whether any correlation exists between the dental health capacity and preferred foods of Korean senior citizens over the age of 65 years. The 5th Korean National Health and Nutrition Survey were used. Tissue health index (T-health), Sound teeth (ST), Functioning teeth index (FS-T), Present teeth (PT), and Missing teeth (MT) were used as variables to assess the dental health capacity of the elderly. Preferred foods of the elderly included 63 foods that were categorized as cereals, pulses and roots, meat and poultry, fish, vegetables, sea algae, fruits, milk and dairy products, cream and sugar, and other foods. For data analysis, the weighted average was taken into consideration to generate planning files, and then complex sample analysis were conducted. For statistical analysis, frequency analysis, t-test, one-way ANOVA, and compound specimen linear regression analysis were conducted. T-health score was significantly high in the group with high preference for cereals, fruits, and other foods. In terms of age and economic status, 65~69 years, 70~74 years, and mid to low range in the income ranges scored high in T-health. ST score was significant in the group that preferred cereals, other foods; the corresponding demographic profiles represent 65~69 years, 70~74 years, and the mid-range income communities. FS-T was significant in relation with a preference for fruits, creams and sugars, other foods; the scores were also high for 65~69 years, 70~74 years, and mid-low to low income groups. PT and MT were significant in the group that preferred cereals and fruits; the same applied for 65~69 years, 70~74 years, and mid-low to low income individuals (p<0.05). Food preferences seemed to vary depending on the dental health state of the elderly, and the dental health state of the elderly may act as a risk factor for nutritional imbalance.