• Journal of Food Hygiene and Safety
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• v.33 no.3
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• pp.151-156
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• 2018

The world is becoming overwhelmed with widespread diseases as antibiotic resistance increases at an alarming rate. Hence, there is a demanding need for the discovery and development of new antimicrobial drugs. The ocean is gifted with many organisms like phytoplankton, algae, sponges, cnidarians, bryozoans, mollusk, tunicates and echinoderms, which are known to produce a wide variety of bioactive secondary metabolites with pharmacological properties. Many new therapeutic drugs have emerged from marine invertebrates, although the large algal community is yet to be explored. The bioactivity possessing secondary metabolites of marine algae include polyphenols, phlorotannins, alkaloids, halogenated compounds, sulfated polysaccharides, agar, carrageenan, proteoglycans, alginate, laminaran, rhamnan sulfate, galactosylglycerol, and fucoidan. These metabolites have been found to have great antimicrobial activities against many human aliments. Studies show that the algal community represents about 9% of biomedical compounds obtained from the sea. This review looks at the evolution of drugs from the ocean, with a special emphasis on the antimicrobial activities of marine algae.

• Korean Journal of Ecology and Environment
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• v.33 no.1 s.89
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• pp.38-50
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• 2000

Seasonal changes of the phytoplankton and the periphyton community were investigated from August 1998 to April 1999 at five stations at the Suer stream in Kwangyang. A total of 112 species of phytoplankton were identified. Of those, the diatoms were present at all stations but the green algae, the bluegreen algae, and the dioflagellates were present at Station 4 and Station 5 more frequently than the other stations. The phytoplankton standing crops varied from 10,100 cells/1 at Station 4 in April 1999 to 1,489,100 cells/1 at Station 4 in October 1998. The seasonal variation patterns of phytoplankton standing crops were different among stations as well as the pattern of presence. The dominant species were as follows: Achnanthes minutissima, Aulacoseira distans v. alpigena, Cocconeis placentula v. lineata, Cymbella minuta, C. silesiaca, Fragilaria arcus v. recta, Peridinium cinctum, Rhizosofenia longiseta, Synedra rumpens and filamentous algae. Of those, Achnanthes minutissima, Rhizosolenia longiseta, Synedra rumpens and filamentous algae showed the highest rate of occupation in the phytoplankton standing crops during the investigated periods. A total of 99 species of periphyton were identified. Among those, the diatoms of the periphyton community were observed frequently rather than those of the phytoplankton community. The ecological indicator values showed ${\bate}$-mesosaprobous in saprobity and was close to eutraphentic in trophic state. There were no considerable differences between the ecological indicator values by planktonic diatoms and periphytic diatoms.

• ALGAE
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• v.22 no.2
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• pp.117-123
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• 2007

The seasonal change of algal flora and intertidal community structures of Bagryoungdo Island was investigated at Dumujin from February to November 2006. The description of subtidal algal community was made in October by Scientific SCUBA-diving. The total of 43 species, including 6 Chlorophytes, 6 Phaeophytes, 29 Rhodophytes and 2 sea grasses were identified in this survey. The occurrence of species according to season, listed as follows, 26 species in winter, 34 in spring, 18 in summer and 18 in autumn. Three species, Laminaria japonica, Neorhodomela aculeata and Ulva pertusa were dominant. The algal zonation of intertidal zone was figured out by Porphyra spp., Gloiopeltis furcata, Caulacanthus okamurae, Gelidium divaricatum - Neorhodomela aculeata, Enteromorpha compressa - Ulva pertusa, Dumontia simplex, Laminaria japonica from upper to lower zone. The zonation of subtidal zone was figured out by Ulva pertusa - Laminaria japonica - Zostera marina (sea grass), crustacean red algal population in autumn. The average of biomass of macroalgae was measured as 119.4 g∙dry wt/m2.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.4
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• pp.387-394
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• 2009

Marine algal flora and community structure were examined seasonally at four study sites around Taean Power Plant, Korea from Jan. to Nov. 2006. A total of 73 algae species (12 green, 9 brown, 52 red) and 1 marine plant were identified. The number of species was maximal at the power plant Discharge (57 species) site followed by Hakampo (46 species), Intake (28 species) and Breakwater (15 species) sites during the study period. The average biomass in dry weight varied from 13.12g/m2 at Intake to 69.60g/m2 at Hakampo. Dominant and sub dominant species in terms of biomass were Gelidium divaricatum - Ulva pertusa at Intake, Chondria crassicaulis - Ulva pertusa at Discharge, Corallin a pilulifera - Chondrus ocellatus at Breakwater, and Corallina pilulifera - Sargassum thunbergii at Hakampo. Species richness of warm tolerant and green algae were greater at Discharge site than Hakampo, showing similar species richness. However, community indices were not distinguishable between Discharge and other study sites. In conclusion, species richness and biomass of seaweeds were greater at Discharge site compared to intake and breakwater sites, and the abundance of warm tolerant and green algal species were higher than Hakampo.

• Fisheries and Aquatic Sciences
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• v.11 no.3
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• pp.159-165
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• 2008

Intertidal benthic algal communities on the shores of Gujido and Daeyeonpyeongdo islets, Korea, were examined in October 2007. At both sites, 45 seaweeds including 7 green, 6 brown and 32 red algae were identified. The number of species at Gujido(38 species) was 1.5 times higher than at Daeyeonpyeongdo(25 species), but seaweed coverage was very similar with about 20%. Dominant seaweeds in terms of coverage and importance value were Hildenbrandtia sp., Caulacanthus okamurae, Ulva pertusa, and Gelidium amansii at Gujido and U. pertusa, Hildenbrandtia sp., Gelidium divaricatum at Daeyeonpyeongdo. The vertical distribution pattern of the seaweeds was G. divaricatum-U. pertusa, Hildenbrandtia sp.-U. pertusa, Hildenbrandtia sp., Ishige okamurae from upper to lower intertidal zone but seaweed zonations were not observed on the Gujido rocky shore. At both sites, coarsely-branched forms were the dominant functional group in species number and percent cover(among benthic algal species). The rocky shores of the two sites were dominated by crustose coralline and green algae, whose presence generally results in decreased seaweed biodiversity and community stability. Therefore, the shores of the Yeonpyeongdo islets are of considerable environmental concern and should be monitored for seaweed species composition and community structure.

• ALGAE
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• v.19 no.1
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• pp.15-22
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• 2004

This study investigated the temporal and spatial dynamics of an epilithic algal community in the Hantan River in November 2001, February, May and August 2002. It was identified a total of an epiphlithic 301 taxa which were composed of 275 species, 16 varieties and 10 unidentified species. The standing crops ranged between 598,600-16,525,200 cells $\cdot$ $cm^2$ and showed the temporal and spatial variations, A higher value was found at the lower station than the upper station in winter, but a higher value was found at the upper station than the lower station in summer due to the effects of typhoons. Chlorophyll concentrations ranged between 13.4-304.2 ${\mu}g$ $\cdot$ $cm^2$. Standing crops and chlorophyll showed similar trends in autumn and winter, but temporal dynamics were not apparent in the overgrowth of Lyngbya, Schizothrix and so others in Cyanophyceae in spring and summer. They were composed of species in Chlorophyceae-Bascillariophyceae-Cyanophyceae and no seasonal effect was detected. Low diversity index values probably indicated the effects of environmental stresses (water temperature, flow and current velocity) other than organic pollution. An assessment of organic pollution using epilithic diatoms (DAIpo) showed $\alpha$-oligosaprobic states at the upper- and mid- stations, and $\alpha$-mesosaprobic states at the lower- stations.

• Korean Journal of Environment and Ecology
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• v.28 no.1
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• pp.10-23
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• 2014

This study was carried out to examine seaweed community structure and distribution of crustose coralline algae at the intertidal and subtidal zones of Gallam, Samchuk, eastern coast of Korea. Total 112 species including 14 of green algae, 33 of brown algae, and 65 of red algae were collected and identified. Among these species, 29 species were found throughout the year. The dominant species which contributed significantly to the total biomass were Ulva pertusa, Colpomenia spp., Sargassum fulvellum, Sargassum fusiforme, Sargassum muticum, Sargassum thunbergii, Corallina pilulifera, and Gelidium elegans. Annual seaweed biomass in dry weight was 66.7 $gm^{-2}$ and maximum biomass was recorded seasonally in summer (107.5 $gm^{-2}$), while minimum was recorded in autumn (36.2 $gm^{-2}$). In seaweed functional group analyses, coarsely branched form was the most dominant functional group constituting from 40.0 to 48.6% of the total flora. Ecological state group ESG II, as an opportunistic species, including sheet form, filamentous form, and coarsely branched form, consisted of 46~61 species, constituting 76.7~82.4%. Crustose coralline algae was observed throughout all seasons. Species of the crustose coralline algae were largely classified into Lithothamnion lemoineae, Lithophyllum okamurai, Lithophyllum yessoense, and Hydrolithon gardineri. The coverage of crustose coralline algae seems to be lower than that of other studies from 36.8% to 11% on average.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.362-372
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• 2011

The relationships among total epiphytes, algal epiphytes and eelgrass ($Zostera$ $marina$ L.) were studied at eelgrass medows from July, 1998 to July, 1999 in Yulim-ri, Yeosu, Korea. Epiphytic diatoms on eelgrass leaves were observed from July to December 1998. From the results of this study, we inferred the following three (3) conclusions : 1) As eelgrass grew older, biomass of epiphytes increased, according to relationships between the leaf length and area of eelgrass and biomass (DW, AFDW and Chl. $a$) of epiphytes. 2) According to the ratio of dry weight, ash-free dry weight and Chlorophyll of epiphytes, the algae with calcareous or siliceous skeletons, such as coralline algae or diatoms, were dominated in the epitphytic algae community. 3) The autotrophic index (AI) calculated from AFDW and Chl. $a$ of epiphytes varied from 151 to 375. However, the period of autotrophic community was shorter than heterotrophic community and the value of AI was high. From these results, we inferred that heterotrophic community, including detritus or microorganisms were dominated in the most of research period.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.276-283
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• 2009

Enrichment in nutrients coming from urban sewage outfalls can lead to eutrophication in coastal areas, which can also change the species composition and community structure of macro algal communities. We investigated the structure of the macro algal community within three rocky shores in order to assess any possible differences in their characteristics. Site 1 was located near Tongyeong city's sewage outfall, Site 2 was located near a public beach area, and Site 3 faced open channel of the Ocean. All three sites were located within the same stretch of the coast, where Site 2 was located between sites 1 and 3. We measured the nutrient concentration in water and the tissue nitrogen content in macro algae samples. Nutrients in the water column surrounding site 1 were high in ammonium ($30.2\pm1.8{\mu}M$), nitrate ($26.2{\pm}0.1{\mu}M$), and phosphate ($2.7{\pm}0.1{\mu}M$) content, and were characterized by low numbers of macroalgal species and species and a low species diversity index. In contrast, site 3 exhibited relatively low nutrient concentration levels and a high number of macroalgal species and a high species diversity index. Comparative analysis showed that the tissue nitrogen content of macroalgae were significantly (P<0.05) affected by the nutrient concentration in the water column. The tissue nitrogen content of green algae within site 1 was higher than the others sites. However, the tissue nitrogen content of brown algae was similar at all three sites. Thus, the tissue nitrogen content of macro algae and the macro algal community structure of intertidal rocky shores were dependent on location and the performance of macroalgal communities was dependent on water quality.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.3
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• pp.262-270
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• 2012

Seaweeds provide habitats in which marine animals can spawn and develop, and serve as a food supply for algaegrazing species such as sea urchins and abalone. Recently, seaweed species have disappeared from coastal ecosystems, leaving barren ground, defined as habitats that have lost their algae forests and where coralline algae containing calcium carbonate components have become encrusted on rocks. The biological causes of barren ground include grazing by herbivores and excessive seaweed harvest. The environmental harm caused by the spread of barren ground includes accelerated eutrophication following the reduction in seaweed, which plays an important role in oceanic purification. In the present study, we identified the relationships between various seaweed species and the occurrence of barren ground. Subtidal benthic macroalgal flora and community structure were observed seasonally on barren ground along vertical transects of rocky shores of Bihwa, Samchuck, and the east coast of Korea from February to November 2006. Fifty-eight seaweed species were identified, including 7 green, 15 brown, and 36 red algae species. There were between 6 and 28 species among seasons. Over the whole study period, average seaweed biomass (g wet wt $m^{-2}$) was 241.90 g, with a seasonal range of 25.26 to 760.34 g. Seaweed biomass declined with increasing seawater depth and ranged between 91.26 and 422.08 g. The vertical distribution of algae was characterized by Undaria pinnatifida and Sargassum honeri at 5 m, S. honeri and U. pinnatifida at 10 m, and U. pinnatifida and Agarum clathratum at 15 m depth. Seasonal patterns in community indices were not found. Community indices showed different patterns along vertical shoreline gradients; the dominance index increased but the richness, evenness, and diversity indices decreased with seawater depth. Sea urchin density was 8 to 24 individ. $m^{-2}$ in Bihwa. These urchin populations had significantly aggregated spatial patterns and recurrent destructive grazing appeared to be occurring.