• Article

    Abundance of Epiphytic Dinoflagellates from Jeju Island during Autumn 2009 Revisited with Special Reference to the Surface-to-Volume Ratio of Substrate Macroalgal Species
    Hyung Seop Kim, Wonho Yih, Mi Ryoung Oh, Keon Gang Jang, Jong Woo Park and Yong Deok Ko
    Occurrence of epiphytic dinoflagellates (EPDs) in coastal waters off Jeju was first reported in 2011 based on 45 substrate samples from 24 ... + READ MORE
    Occurrence of epiphytic dinoflagellates (EPDs) in coastal waters off Jeju was first reported in 2011 based on 45 substrate samples from 24 macroalgal species. When re-analyzing, the extreme heterogeneous distribution of whole and genus-specific EPDs was reconfirmed across the sampling stations and substrate macroalgal species, as well as even across substrate samples of the same species. Abundance maximum of an EPD genus (cells g-wwt-1) at a fixed surface-to-volume ratio (SA/V ratio) of the macroalgal species increased as the SA/V ratio increased up to 500 (cm2 cm-3). However, the abundance maximum of Ostreopsis further increased even in the MG2 (morphological group 2) macroalgae with the SA/V ratios over 500. The number of substrate macroalgal species on the plane of the MG and sampling station was more or less evenly scattered than the average EPD abundance, which was primarily driven by Gambierdiscus and Ostreopsis. Of the total EPD abundance of the five stations, 90.6% were represented by the two most common and abundant genera, Gambierdiscus and Ostreopsis, each accounting for 41.6% and 49.0%. Spatially, 95.9% of the total EPD abundance was found in St. 4 and St. 5, of which St. 4 with higher water temperature had more Ostreopsis spp. (31.8%), and St. 5 with higher salinity had more Gambierdiscus spp. (27.3%). Thus, the environmental transition to favorable T-S condition to MG2, the thin filamentous macroalgal group with very high SA/V ratios, is thus likely to support further success in EPD genera led by Ostreopsis in the coastal waters of Jeju. - COLLAPSE
    September 2021
  • Article

    Antioxidant and Anti-inflammatory Activities of the Halophyte Cyrtomium falcatum

    염생식물 도깨비고비의 항산화 및 항염증 효과

    Hyunmo Kim, Hojun Kim, Chang-Suk Kong, Bong Ho Lee, Hyun-Bo Sim, and Youngwan Seo

    김현모, 김호준, 공창숙, 이봉호, 심현보, 서영완

    In the present study, the halophyte C. falcatum extract and its solvent fractions (n-hexane, 85% aqueous methanol, n-butanol, and water ... + READ MORE
    In the present study, the halophyte C. falcatum extract and its solvent fractions (n-hexane, 85% aqueous methanol, n-butanol, and water) were evaluated for antioxidant and anti-inflammatory activities. Antioxidative ability was measured by DPPH radical, intracellular reactive oxygen species (ROS) and peroxynitrite scavenging, DNA oxidation inhibition, and ferric reducing antioxidant power (FRAP). For DPPH radical and peroxynitrite scavenging, DNA oxidation inhibition, and FRAP, 85% aq.MeOH and n-BuOH fractions showed significant scavenging activity. For production of intracellular ROS in HT-1080 cells, 85% aq.MeOH fraction showed the highest scavenging activity. In addition, anti-inflammatory activity was also assessed by measuring the inhibitory effect against mRNA expression of pro-inflammatory factors (NO, IL-1β, IL-6 and COX-2) in LPS-stimulated Raw 264.7 macrophages. For NO production, crude extract exhibited a strong inhibitory effect at a concentration of 100 μg/ml. For mRNA expression of pro-inflammatory cytokines (IL-1β, IL-6, and COX-2), n-BuOH greatly suppressed expression levels of IL-1β and IL-6 at 100 μg/ml concentration while 85% aq. MeOH fraction significantly inhibited that of COX-2 even at 100 μg/ml. These results suggest that C. falcatum may be used as a potential source for the development of a natural antioxidant or anti-inflammatory agent. - COLLAPSE
    September 2021
  • Article

    Habitat Environments and Spatiotemporal Distribution of Clithon retropictum at the Estuaries of Bonggang and Miryoung Streams in the Southern Coast of Korea

    남해안 봉강천과 미룡천 하구에서 기수갈고둥의 분포 및 서식지 환경 특성

    Keon Gang Jang, Min-Seop Kim, Soo-Gun Jo, Wonho Yih and Hyung Seop Kim

    장건강, 김민섭, 조수근, 이원호, 김형섭

    At the estuaries of Bonggang and Miryong streams in the Korean southern coast, the spatiotemporal distribution and habitat environment of a nerite ... + READ MORE
    At the estuaries of Bonggang and Miryong streams in the Korean southern coast, the spatiotemporal distribution and habitat environment of a nerite snail, Clithon retropictum (Gastropoda: Neritidae), which has been assigned as a legally protected species of Korea, were explored. Physicochemical environmental factors such as water temperature, salinity, tidal level distribution as well as biotic environments (chlorophyll-a concentration and epilithic microalgae composition) were monitored every month. The relationships between the environmental factors and spatiotemporal distribution of the nerite snail population were analyzed. Water temperature, salinity, and water level varied by season and lunar tidal rhythm. The spatiotemporal distribution of the nerite snail was mostly related to water salinity. Among epilithic algae which were the priority prey of snails, blue-green algae and green algae dominated in summer and autumn, while diatoms predominated during winter and spring. Chlorophyll-a concentration was highly and positively correlated with the population density of the nerite snail. The correlation coefficients were different depending on the taxon (Family) of epilithic algae. The mean population density was 302.2 inds m-2 and 271.8 inds m-2 in Bonggang Stream and Miryong Stream, respectively. The egg capsules of the nerite snail in the two habitats were observed from March (in Bonggang Stream) or April (in Miryong Stream) to August, and newly hatched juveniles recruited in the habitats from August were assessed with regard to frequency distributions of shell width. The occurrence of large-sized snails in upper stream reaches of both Bonggang and Miryong indicated the movement of spats from the mouth to the upper reaches during the whole life cycle. - COLLAPSE
    September 2021
  • Article

    Oxidative Stress and Apoptosis in Goldfish (Carassius auratus) Caused by Exposure to Different Concentrations of Micro-polystyrene
    Zhongze Li, Jin Ah Song and Cheol Young Choi
    Microplastic contamination in waterbodies is a growing source of concern for researchers and other stakeholders. We investigated oxidative stress and toxicity in ... + READ MORE
    Microplastic contamination in waterbodies is a growing source of concern for researchers and other stakeholders. We investigated oxidative stress and toxicity in goldfish (Carassius auratus) in response to exposure to 1-µm diameter micro-polystyrene (MP) at concentrations of 0, 10, 100, and 1000 beads/mL (MP 0, MP 10, MP 100, and MP 1000 groups) for 7 d (at day 0, 1, 3, 5, and 7). We analyzed the survival rates; superoxide dismutase (SOD) and catalase (CAT) mRNA expression levels in the liver; SOD and CAT activity in the plasma; caspase-3 mRNA expression in the liver; and the levels of hydrogen peroxide (H2O2) in plasma. Terminal transferase dUTP nick end labeling (TUNEL) assays were also conducted to determine apoptosis levels in the liver. All fish in the MP 1000 group died by day 7 and the MP 100 group had a lower survival rate than the MP 10 and MP 0 groups. The mRNA expression as well as SOD, CAT, and caspase-3 activity levels were increased significantly with increases in MP concentration and exposure time. Finally, according to the TUNEL assay, more apoptosis was observed in the MP 1000 group at day 5 than in other groups. In summary, MP concentrations above 100 beads/mL caused death and oxidative stress to goldfish. We conclude that MP can cause oxidative stress and apoptosis in goldfish, which leads to death. - COLLAPSE
    September 2021
  • Article

    Current Status and Evaluation of Fisheries By-products: Major Options to Marine Bioindustrial Application

    수산부산물의 발생·이용 실태 평가 및 해양바이오 산업화 방안

    Soeon Ahn, Won-Kyu Lee, Duckhee Jang and Do-Hyung Kang

    안소언, 이원규, 장덕희, 강도형

    Since the existing mass production and consumption systems are no longer sustainable, countries are pushing for policies to make fisheries by-products as ... + READ MORE
    Since the existing mass production and consumption systems are no longer sustainable, countries are pushing for policies to make fisheries by-products as resources in an eco-friendly manner, and international standards are also being strengthened to increase the value of by-products. In Korea, economic and environmental perceptions of the by-products are rapidly changing, such as realizing carbon neutrality and enhancing circular resources by Korean Sustainable Development Goals. Raw materials derived from the by-products have been steadily imported from 2018. In particular, the number of imports of fish collagen peptides was only 16 number of times in 2017, but was rapidly increased to 483 number of times in 2020. Simultaneously, the demand for raw materials and nutrients for health functional food derived from fish by-products, which did not exist statistically until 2017, started to arise from 2018, and in 2019, consumption of high-value-added raw materials for fish by-products increased by 45% compared to the previous year. However, limitations are in legal and biotechnical industry aspects while its value as a biomaterial is recognized in the by-products-related industry. In this study, therefore, the status of by-products for upcycling biomaterials was reported and provided a scientific basis for supporting governmental strategies. In order to fulfill with the principles of a sustainable circular economy, the factors on hinder the marine bio-industrialization of the by-products were derived and suggested directions and plans for development into a high-value added the by-products as the marine bio-industry by substituting imported raw materials to support the development. - COLLAPSE
    September 2021
  • Review

    Anthropogenic Gadolinium (Gd) Inputs into the Ocean: Review and Future Direction

    인위적 기원 가돌리늄(gadolinium)의 해양 유입 연구 동향 및 향후 연구 방향

    Intae Kim

    김인태

    Gadolinium (Gd), one of a rare earth element (REE), has been widely used worldwide since the 1980s, as a resource material for ... + READ MORE
    Gadolinium (Gd), one of a rare earth element (REE), has been widely used worldwide since the 1980s, as a resource material for contrast agents injected into examiners of magnetic resonance imaging (MRI) test. The organic complexed form of Gd shows an extremely stable behavior in natural environment (water), so is known that the artificial Gd from medical uses is not removed from the waste water treatment plant (WWTP) and eventually introduced into the ocean through the estuary. Since the 1990s, some previous studies have often been conducted on Gd anomalies in natural water and their effects an artificial origin from land or metropolitan areas, but little research has been potential impacts on the ocean water. In this paper, we review and introduce recent studies related to Gd anomaly in natural water and related marine effects, and also propose the future research directions. - COLLAPSE
    September 2021
  • Note

    Sensitivity Analysis of Wind-Wave Growth Parameter during Typhoon Season in Summer for Developing an Integrated Global/Regional/Coastal Wave Prediction System

    전지구․지역․국지연안 통합 파랑예측시스템 개발을 위한 여름철 태풍시기 풍파성장 파라미터 민감도 분석

    Youjung Oh, Sang Meong Oh, Pil-Hun Chang, KiRyong Kang and Il-Ju Moon

    오유정, 오상명, 장필훈, 강기룡, 문일주

    In this study, an integrated wave model from global to coastal scales was developed to improve the operational wave prediction performance of ... + READ MORE
    In this study, an integrated wave model from global to coastal scales was developed to improve the operational wave prediction performance of the Korean Meteorological Administration (KMA). In this system, the wave model was upgraded to the WaveWatch III version 6.07 with the improved parameterization of the source term. Considering the increased resolution of the wind input field and the introduction of the high-performance KMA 5th Supercomputer, the spatial resolution of global and regional wave models has been doubled compared to the operational model. The physical processes and coefficients of the wave model were optimized for the current KMA global atmospheric forecasting system, the Korean Integrated Model (KIM), which is being operated since April 2020. Based on the sensitivity experiment results, the wind-wave growth parameter (βmax) for the global wave model was determined to be 1.33 with the lowest root mean square errors (RMSE). The value of βmax showed the lowest error when applied to regional/coastal wave models for the period of the typhoon season when strong winds occur. Applying the new system to the case of August 2020, the RMSE for the 48-hour significant wave height prediction was reduced by 13.4 to 17.7% compared to the existing KMA operating model. The new integrated wave prediction system plans to replace the KMA operating model after long-term verification. - COLLAPSE
    September 2021
  • Note

    Improvements for Successful Mooring of Ocean Buoys

    성공적인 해양부이 계류를 위한 개선 방안

    Dawoon Jung, Joonseong Park and Kyu-Min Song

    정다운, 박준성, 송규민

    In-situ experiment using ocean buoys is a direct ocean observation and has been playing an important role from the past to the ... + READ MORE
    In-situ experiment using ocean buoys is a direct ocean observation and has been playing an important role from the past to the present based on high reliability. The ocean buoy is operated more stable than before due to the technological development of communication (GPS, satellite, …) and equipment, but still moored buoys are not free from various accidents occurring in the ocean. Nevertheless, there is currently a lack of countermeasures or manuals about mooring accidents. Therefore, in this study, based on the experience of operating buoys conducted for many years, the advantages and disadvantages of ocean buoys according to size were analyzed. and legal procedures before and after buoy mooring were presented to enhance the use of buoys. And it is suggested to realize successful experiment by proposing considerations before mooring the buoy in preparation for an accident. - COLLAPSE
    September 2021