• Journal of the Korean Chemical Society
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• v.33 no.3
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• pp.321-325
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• 1989

There has been a continuing interest in the sterols and sterodis of marine organisms. The most exciting results of recent studies have been the characterization of a host of novel sterols, many with unique alkylation patterns in the side chain, but some with modified ring structures. The isolation and characterization of three sterols from the Korean alga codium fragile are presented. The major sterol was (24S)-24-ethylcholesta-5,25-dien-3${\beta}$-ol (clerosterol) and two minors are codisterodl and cholesterol.

• Journal of Marine Bioscience and Biotechnology
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• v.5 no.4
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• pp.26-32
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• 2011

Green fluorescent protein (GFP), a very important biological agent that involves shifting the color of bioluminescence from blue to green in luminous coelenterates and to increase the quantum yield of light emission. GFP discovered in medusa, Aequorea victoria is a key factor of various biotechnological and cell biological applications. Beside these applications, GFP of A. victoria is generally stable, which does not require co-factors for activity and can be functionally expressed in different bacterial species. This property of GFPs from A. victoria permits them to be a unique tool to monitor gene expression and protein localization in different organisms. The present review brings out the past milestones and future perspectives on GFPs, with an elaborative reviewing on its applications.

• Animal Systematics, Evolution and Diversity
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• v.36 no.4
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• pp.408-415
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• 2020

The suborder Hyperiidea is an abundant crustacean zooplankton in pelagic communities with copepods and euphausiaceans. Hyperiidean amphipods are known to be commensals or parasites of gelatinous organisms such as medusae, siphonophores, ctenophores, and salps. Korean hyperiid amphipods have not received taxonomical attention since the 1970s. During a survey of pelagic crustacean species, two species of hyperiid amphipods, Phronima atlantica Guérin-Méneville, 1836 belonging to the family Phronimidae and Oxycephalus clausi Bovallius, 1887 belonging to the family Oxycephalidae, were found on Dokdo, East Sea, Korea. These two species are new to Korean waters. In the present study, we provide descriptions and illustrations of these two hyperiid species.

• ALGAE
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• v.36 no.4
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• pp.333-340
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• 2021

Phylotranscriptomics is the study of phylogenetic relationships among taxa based on their DNA sequences derived from transcriptomes. Because of the relatively low cost of transcriptome sequencing compared with genome sequencing and the fact that phylotranscriptomics is almost as reliable as phylogenomics, the phylotranscriptomic analysis has recently emerged as the preferred method for studying evolutionary biology. However, it is challenging to perform transcriptomic and phylogenetic analyses together without programming expertise. This study presents a protocol for phylotranscriptomic analysis to aid marine biologists unfamiliar with UNIX command-line interface and bioinformatics tools. Here, we used transcriptomes to reconstruct a molecular phylogeny of dinoflagellate protists, a diverse and globally abundant group of marine plankton organisms whose large and complex genomic sequences have impeded conventional phylogenic analysis based on genomic data. We hope that our proposed protocol may serve as practical and helpful information for the training and education of novice phycologists.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.4
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• pp.121-136
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• 2022

Purpose : Marine therapy is an activity that promotes public health such as constitution improvement, immunity improvement, and anti-aging by utilizing marine therapeutic resources such as seawater, mud, seaweed, salt and sea climate. In Europe developed countries, the marine therapy industry has been developing for centuries, with France, Germany, and Israel leading the way. Currently, it has achieved great industrial achievements and is of great help in improving the human health. The purpose of this study is to investigate how marine therapeutic resources benefit to human health, as well as how to study and utilize their efficacy. We analyzed previous research articles related to the effects of marine therapeutic resources. Methods : The study included a total of 830 published literatures in the last 20 years from the Republic of Korea and other contries. PubMed and Google Scholar were utilized to collect the foreign source while the local scientific publications were accessed through the Korean Education and research Information Service (KERIS) and Korean studies Information Service System (KISS). The keywords used to search foreign literature were "marine therapy", "Thalassotherapy", "seawater", "deep seawater", "saline groundwater", "sand therapy", "mud therapy", "hydrotherapy", "seaweed", "Sun light", "sea salt", "marine animal", and "marine microorganisms" were combined, and for the domestic literature, the keywords were "marine therapy", "marine therapeutic resources", "seawater", and "sand". Results : A total of 830 research papers were found as a result of searching for domestic and international papers related to marine therapeutic resources. The collected documents were classified into 175 seawater resources, 259 marine mineral resources, 41 marine environment, and 355 marine organisms. The efficacy of each marine therapeutic resources was analyzed. By resources type, there were about 213 papers on the efficacy of seaweed, followed by about 175 papers on seawater, 142 on microorganisms, 124 on mud/peat, and sand, salt, minerals and others are appeared in order (Table 1). Conclusion : Korea has the highest marine biodiversity index, excellent tidal flats, four distinct seasons, and various sea environments of the East sea, Yellow sea, South sea and Jeju sea. For this reason, Korea has a much more diverse marine therapeutic resources than other advanced countries in the marine therapy industry. prebiously, we thought that the sea was only valuable as a shipping port and fishery industry. But now, it been shown that the ocean can become a new industrial field which can contribute to human health and well-being by providing healing and therapy to people through the gift of marine resources.

• Ocean and Polar Research
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• v.29 no.3
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• pp.205-216
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• 2007

The purpose of this study was to investigate effects of large scale marine sand mining on the marine ecological community. For the study, four stations along the coast were selected and monitored in 1998 and 2001 at mining areas and non-mining areas about the Gyeonggi Bay. The result revealed that in 1998, 9 species of fishes, 16 species of crustaceans, and 6 species of mollusks were collected where as in 2001, 11 species of fishes, 5 species of crustaceans, and 2 species of mollusks were collected, uncovering the fact that fishes have diversified while crustaceans and mollusks have reduced on a grand scale. Also, there were two key characteristics regarding the changes of biological communities in mining and nonmining areas. The first was the dwindling of crustaceans inhabiting the sand area. This outcome may be accounted for by the facts that physical removal of seabed sediments and re-sediment due to expansion of floating particles cause direct influence on the ocean floor ecosystem and have continuous effect on the communities of crustaceans which feed on them. Secondly, the newly arrived species and their population during spring and summer seasons have increased in the non-mining areas and have decreased in the mining area. It can be concluded that highly nomadic fish species migrate toward areas with less disturbance or destruction of ecosystem from marine sand mining, and consequently, the communities of fishes change in the sea area. Setting aside the characteristics of the investigated sea areas where the arriving conditions of species vary by seasons, the clear differences of population of organisms in those areas are due to environmental alterations owing to the marine sand mining ; if those large-scale marine sand mining activities continue in the Gyeonggi Bay, their effects on biological communities in the areas will only grow.

• Ocean and Polar Research
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• v.28 no.3
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• pp.225-236
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• 2006

Seagrass meadows are considered as critical habitats for a wide variety of marine organisms in coastal and estuarine ecosystems. In many cases, studies on the spatial/temporal distribution of seagrass have depended on direct observations using SCUBA diving. As an alternative method fur studying seagrass distribution, an application of hydroacoustic technique has been assessed for mapping seagrass distribution in Dongdae Bay, on the south coast of Korea, in September 2005. Data were collected using high frequency transducer (420 kHz split-beam), which was installed with towed body system. The system was linked to DGPS to make goo-referenced data. Additionally, in situ seagrass distribution has been observed using underwater cameras and SCUBA diving at four stations in order to compare with acoustic data. Acoustic survey was conducted along 23 transects with 3-4 blot ship speed. Seagrass beds were vertically limited to depths less than 3.5m and seagrass height ranged between 55 and 90cm at the study sites. Dense seagmss beds were mainly found at the entrance of the bay and at a flat area around the center of the bay. Although the study area was a relatively small, the vertical and spatial distributions of the seagrass were highly variable with bathymetry and region. Considering dominant species, Zostera marina L., preliminary estimation of seagrass biomass with acoustic and direct sampling data was approximately $56.55g/m^2$, and total biomass of 104 tones (coefficient variation: 25.77%) was estimated at the study area. Hydroacoustic method provided valuable information to understand distribution pattern and to estimate seagrass biomass.

• ALGAE
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• v.33 no.3
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• pp.269-278
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• 2018

Ocean warming can have significant negative impacts on population genetic diversity, local endemism and geographical distribution of a wide range of marine organisms. Thus, the identification of conservation units with high risk of extinction becomes an imperative task to assess, monitor, and manage marine biodiversity for policy-makers. Here, we surveyed population structure and genetic variation of the red seaweed Gracilaria vermiculophylla along the coast of China using genome-based amplified fragment length polymorphism (AFLP) scanning. Regardless of analysis methods used, AFLP consistently revealed a south to north genetic isolation. Populations at the southern coast of China showed unique genetic variation and much greater allelic richness, heterozygosity, and average genetic diversity than the northern. In particular, we identified a geographical barrier that may hinder genetic exchange between the two lineages. Consequently, the characterized genetic lineage at the southern coast of China likely resulted from the interplay of post-glacial persistence of ancestral diversity, geographical isolation and local adaptation. In particular, the southern populations are indispensable components to explore evolutionary genetics and historical biogeography of G. vermiculophylla in the northwestern Pacific, and the unique diversity also has important conservation value in terms of projected climate warming.

• Ocean and Polar Research
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• v.44 no.4
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• pp.331-338
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• 2022

The high latitude scleractinian coral Alveopora japonica Eguchi, 1965 occurs in high density in the shallow rocky subtidal in Jeju Island, forming coral carpets. Despite its ecological role providing a unique habitat for other benthic organisms, the benthic fauna associated with the A. japonica coral carpet is poorly known. To identify fauna associated with the coral carpet, we explored three sites dominated by A. japonica and one control site on northwestern Jeju Island in May 2013. Using SCUBA, we collected A. japonica and the epibenthic mega-fauna associated with the colonies in 1×1 m² and identified them to the species level. At a depth of 10 to 15 m, A. japonica colonies heavily covered the seafloor, forming a layer called a coral carpet, with a density of 94 (Keumneung-ri), 133 (Biyangdo), and 155 (Gwidok-ri) colonies/m². Thirty-four molluscan species were identified from the four sites, including 20 bivalves and 14 gastropods. The coral carpets were enriched with sessile bivalves compared to the control site, as we identified twenty bivalve and eight gastropod species from the coral carpets. Most bivalve species associated with the coral carpets had tropical-subtropical affinities, while gastropods were mainly subtropical and subtropical-low boreal species. Leiosolenus lischkei M. Huber, 2010, in the family Mytilidae and Barbatia steamsi (Pilsbry, 1895), in the family Arcidae, were the two most abundant bivalve species in the coral carpet, L. lischkei being a borer, and B. stearnsi a nestler. The tropical to subtropical Pacific star shell Astralium haematragum (Menke, 1829)was the most abundant gastropod at the study sites. The bivalves and gastropods associated with the coral carpet were small-sized juveniles or sub-adults, suggesting that the coral carpet provides a micro-habitat for the bivalves and gastropods.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.3
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• pp.262-277
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• 2024

The mid-eastern coast of Korea is located at the boundary between cold and warm currents, which causes changes in the distribution and composition of marine organisms in response to fluctuations in the marine environment. To understand the seasonal changes in the seaweed community, we investigated its species composition, biomass, coverage, and frequency from November 2022 to August 2023. A total of 45 species (7 green, 18 brown, and 20 red algae) were found in the study area. In the intertidal zone, the number of species decreased from autumn to summer; the biomass peaked during winter (471.94 g wet weight m^-2). Seaweed groups were the dominant functional groups, which were coarsely branched, filamentous, and sheet-like during autumn, winter, spring, and summer. The morpho-functional group was dominated by turf species. In the subtidal zone, the number of species increased during autumn to spring, whereas the biomass peaked during spring (655.27 g wet weight m^-2). The functional group was dominated by coarsely branched species throughout all four seasons, whereas the morpho-functional group was dominated by canopy species. Consequently, changes in the biomass of brown and red algae are recognized as key drivers of seasonal changes in seaweed communities.