• Article

    Changes of Current and Wave Patterns Depending on Typhoon Pathways in a Shallow Channel between Jeju and Udo Island

    태풍 경로에 따른 제주 우도수로에서의 해류와 파랑 특성 변화

    Ji-Seok Hong, Jae-Hong Moon, Seok-Hoon Yoon, and Woo Seok Yoon

    홍지석, 문재홍, 윤석훈, 윤우석

    A shallow channel between Jeju and Udo Islands, which is located in the northeastern Jeju Island, is influenced by storm- or typhoon-induced … + READ MORE
    A shallow channel between Jeju and Udo Islands, which is located in the northeastern Jeju Island, is influenced by storm- or typhoon-induced currents and surface waves as well as strong tidal currents. This study examines the typhoon-induced current and wave patterns in the channel, using Acoustic Doppler Current Meter (ADCP) measurements and an ocean-wave coupled modeling experiment. Three typhoons were chosen - Chaba (2016), Soulik (2018), and Lingling (2019) - to investigate the responses of currents and waves in their pathways. During the pre-typhoon periods, dominant northward flow and wave propagation were observed in the channel due to the southeasterly winds before the three typhoons. After the passage of Chaba, which passed over the eastern side of Jeju Island, the northward flow and wave propagation were totally reversed to the opposite direction, which was attributed to the strong northerly winds on the left side of the typhoon. In contrast, in the cases of Soulik and Lingling, which passed over the western side of Jeju Island, strong southerly winds on the right side of the typhoons continuously intensified the northward current and wave propagation in the channel. The model-simulated current and wave fields reasonably coincided with observational data, showing southward/northward flow and wave propagation in response to the right/left side of the typhoon pathways. Typhoon-induced downwind flows, and surface waves could enhance up to 2m/s and 3m due to the strong winds that lasted for more than 12 hours. This suggests that the flow and wave patterns in the Udo channel are highly sensitive to the pathway of typhoons and accompanying winds; thus, this may be a crucial factor with regard to the movement of seabed sediments and subsequent coastal erosion. - COLLAPSE
    30 December 2021
  • Article

    Estimation of Sea Surface Height using Pressure-recording Inverted Echo Sounders Data in the Mindanao Current Region

    민다나오 해류 해역에서 PIES 자료를 이용한 해수면 산출

    Chorong Hwang, Hong Sik Min, Chanhyung Jeon, Dong Guk Kim, and Jae-Hun Park

    황초롱, 민홍식, 전찬형, 김동국, 박재훈

    Sea surface height (SSH) anomalies were estimated from data recorded by four pressure-recording inverted echo sounders (PIESs) in the Mindanao Current region … + READ MORE
    Sea surface height (SSH) anomalies were estimated from data recorded by four pressure-recording inverted echo sounders (PIESs) in the Mindanao Current region over a duration of 2 years from December 2017 to November 2019. The steric components of SSH anomalies were derived from round-trip acoustic travel times from the sea floor to the sea surface, whereas mass-loading components were derived from bottom pressures. Temporal variabilities in the total (steric and mass-loading) SSH anomalies and the steric component are extremely similar; this result implies that the steric component plays a major role in SSH anomalies in this region. Comparisons of the PIES-derived SSH anomalies with satellite-measured SSH anomalies reveal that the former has less temporal variability. Correlation coefficients between the total SSH anomalies and satellite-measured SSH anomalies are less than 0.85, which is lower than the correlation coefficient between the steric components and satellite-measured SSH anomalies. - COLLAPSE
    30 December 2021
  • Article

    Evaluation of International Quality Control Procedures for Detecting Outliers in Water Temperature Time-series at Ieodo Ocean Research Station

    이어도 해양과학기지 수온 시계열 자료의 이상값 검출을 위한 국제 품질검사의 성능 평가

    Yongchim Min, Hyunjung Jun, Jin-Yong Jeong, Sung-Hwan Park, Jaeik Lee, Jeongmin Jeong, Inki Min, and Yong Sun Kim

    민용침, 전현정, 정진용, 박숭환, 이재익, 정종민, 민인기, 김용선

    Quality control (QC) to process observed time series has become more critical as the types and amount of observed data have increased … + READ MORE
    Quality control (QC) to process observed time series has become more critical as the types and amount of observed data have increased along with the development of ocean observing sensors and communication technology. International ocean observing institutions have developed and operated automatic QC procedures for these observed time series. In this study, the performance of automated QC procedures proposed by U.S. IOOS (Integrated Ocean Observing System), NDBC (National Data Buy Center), and OOI (Ocean Observatory Initiative) were evaluated for observed time-series particularly from the Yellow and East China Seas by taking advantage of a confusion matrix. We focused on detecting additive outliers (AO) and temporary change outliers (TCO) based on ocean temperature observation from the Ieodo Ocean Research Station (I-ORS) in 2013. Our results present that the IOOS variability check procedure tends to classify normal data as AO or TCO. The NDBC variability check tracks outliers well but also tends to classify a lot of normal data as abnormal, particularly in the case of rapidly fluctuating time-series. The OOI procedure seems to detect the AO and TCO most effectively and the rate of classifying normal data as abnormal is also the lowest among the international checks. However, all three checks need additional scrutiny because they often fail to classify outliers when intermittent observations are performed or as a result of systematic errors, as well as tending to classify normal data as outliers in the case where there is abrupt change in the observed data due to a sensor being located within a sharp boundary between two water masses, which is a common feature in shallow water observations. Therefore, this study underlines the necessity of developing a new QC algorithm for time-series occurring in a shallow sea. - COLLAPSE
    30 December 2021
  • Article

    Ultrastructural and Molecular Characterization of Surirella atomus Hustedt 1955 (Bacillariophyta, Surirellalceae), A Newly Recorded Species in Korea
    Sung Min An, Jae Hoon Noh, Ji Hoon Kim and Nam Seon Kang
    Surirella atomus Hustedt 1955, surirelloid diatom, were obtained from Hampyeong Bay, Mu-an, in the west coast of Korea. We describe the first … + READ MORE
    Surirella atomus Hustedt 1955, surirelloid diatom, were obtained from Hampyeong Bay, Mu-an, in the west coast of Korea. We describe the first record of S. atomus in Korea and report its ultrastructure and molecular characteristics for the first time. For molecular analysis, rbcL gene and cob gene were sequenced. This species is very small in size, making it difficult to observe its morphological features under a light microscope. Even with a scanning electron microscope, it has no unique structure in the valve. It is morphologically very simple. This rare species was known as a marine benthic species. However, it appears to be widely distributed in marine, freshwater, and brackish environments according to the literature documenting this species. In terms of phylogeny, S. atomus has been tentatively linked to Petrodictyon gemma, but the phylogenetic placement of S. atomus seems to be still uncertain, in a manner that is similar to S. febigeri. However, morphological observations derived from this study suggest that this species belongs to the genus Surirella. - COLLAPSE
    30 December 2021
  • Article

    Spatial-temporal Variation of Fouling Organisms Recruited on a Fishing Net based on Community Structure, Tongyeong, Southern Coast of Korea

    통영 연안 가두리 양식용 그물에 가입되는 오손생물군집의 시·공간적 비교

    Hyuk-Jin Kim, Kon-Tak Yoon, and Heung-Sik Park

    김혁진, 윤건탁, 박흥식

    To understand the composition and community changes of benthic species by water depth (5 m, 20 m, 30 m) in the cage … + READ MORE
    To understand the composition and community changes of benthic species by water depth (5 m, 20 m, 30 m) in the cage facilities, net substrate made of fish cages were installed at intervals of 2 months from March to September 2019, which is the main period of sessile organism recruitment. Water temperature and salinity varied in the ranges of 1~5℃ and 1~4 mg/L at 5 m from June to August, respectively, and less difference was observed according to water depth in other investigation periods. A total of 37 benthic animals were recruited, and Kamptozoa unid., Caprella scaura and Jassa slatteryi were verified during the entire study period. Mytilus galloprovincialis, a Mediterranean mussel, showed seasonality dominant only from spring to early summer (March to July). The community structure classified by temporal and spatial factors, and Bugula neritina, Kamptozoa unid., and Sertularella sp. contributed to the formation of the community. The depth of 5 m was exposed to environmental changes in water temperature and salinity temporally, so there was a seasonal variation in the composition of the sessile organism, but at depths of 20 m and 30 m, there was less significant environmental change and it showed relatively stable than 5 m. - COLLAPSE
    30 December 2021
  • Article

    Mesozooplankton Community Structure in the Yellow Sea in Summer

    여름철 황해의 중형동물플랑크톤 군집 구조

    Garam Kim and Hyung–Ku Kang

    김가람, 강형구

    We investigated mesozooplankton community in the Yellow Sea in summer immediately after the typhoon passed. Total mesozooplankton density ranged from 1,323 to … + READ MORE
    We investigated mesozooplankton community in the Yellow Sea in summer immediately after the typhoon passed. Total mesozooplankton density ranged from 1,323 to 6,397 ind. m-3 and the biomass ranged from 3 to 28 mg C m-3 by stations. The dominant species of the research area were Paracalanus parvus s.l., Oithona atlantica, Acartia omorii, Oikopleuridae, Sagittoidae juvenile and Calanus sinicus in that order. Mesozooplankton community was divided into two groups by cluster analysis : the stations located in coastal and open seas as one group, and the stations located in the middle into another group. The number of species, density and richness of mesozooplankton were significantly lower in the middle region. Mesozooplankton density and biomass were not significantly correlated with chl-a concentrations, unlike previous studies in spring and autumn. This community characteristic in summer may be due to the passing of the typhoon, or other environmental influences. - COLLAPSE
    30 December 2021
  • Article

    Effect of Marine Environment Changes on the Abundance and Community Composition of Cyanobacteria in the South Sea of Korea

    남해 해역의 해양환경변화가 시아노박테리아 개체수와 군집 조성에 미치는 영향

    JongSeok Won, Yeonjung Lee, Howon Lee and Jae Hoon Noh

    원종석, 이연정, 이호원, 노재훈

    To investigate the effect of seasonal marine environment conditions on the cyanobacteria abundance and diversity in the South Sea, four-seasonal surveys were … + READ MORE
    To investigate the effect of seasonal marine environment conditions on the cyanobacteria abundance and diversity in the South Sea, four-seasonal surveys were conducted along the 127.5°E survey transect line in the central South Sea using flow cytometry and 16S-23S ITS on the Miseq platform from August 2016 to May 2017. The average abundance of Synechococcus varied from 3.3 × 103 to 7.4 × 104 cells ml-1. The abundance was the highest in the summer and the lowest in the winter, and the abundance fluctuated according to water temperature. The abundance was high in the outer sea affected by TWC. However, in summer, the Coastal areas affected by the Yangtze River were more populated than the outer sea. Prochlorococcus was rare and could not penetrate into coastal areas due to the fronts, but showed its dominance in the waters influenced by the TWC. Synechococcus clades II, VII, IX, CRD1, and CRD2 were predominant in the outer sea area affected by the TWC. In the coastal area, clades I and IV showed higher dominance whereas clades V, VI, WPC1, and 5.3-MS3 with euryhaline characteristics, showed a high dominance rate in the water masses affected by the low-salinity water of the Yangtze River in the summer. Clade XVI, XVII, CB1, CB5, and 5.3-I/II showed high dominance in nutrient-rich waters in the summer with increased water temperature. The abundance and community composition of cyanobacteria changed in the South Sea due to the influence of the TWC and stratification. In the summer, the abundance and the community composition differed, and were mainly affected by the general influence of the TWC in addition to the influence of the Yangtze River low-salinity water. - COLLAPSE
    30 December 2021
  • Article

    Productivity Analysis for Multi-Wells Depressurization of Gas Hydrate Bearing Sediments in Ulleung Basin, East Sea of Korea

    동해 울릉분지 가스하이드레이트 퇴적층 내 다중정 감압에 따른 생산성 분석

    Seo-Yoon Moon, Hyo-Jin Shin and Jong-Se Lim

    문서윤, 신효진, 임종세

    A field scale productivity analysis is required for the development of gas hydrate in marine sedimentary layers to verify the field applicability … + READ MORE
    A field scale productivity analysis is required for the development of gas hydrate in marine sedimentary layers to verify the field applicability of production techniques and to improve productivity. In this study, the productivity resulting from the application of depressurization using multi-wells for the development of gas hydrate in the Ulleung Basin, East Sea of Korea, was determined. A numerical analysis model reflecting the conditions of candidate sites for the Ulleung Basin was constructed, and the productivity and dissociation behavior were comparatively analyzed. The pressure propagation and gas hydrate dissociation region by the multi-wells were wider and the productivity was higher than that of a single well. Different depressurization effects according to the spacing of multi-wells affected productivity. The results provide basic data for productivity analysis when establishing a field test production plan for the Ulleung Basin. - COLLAPSE
    30 December 2021
  • Article

    Topographic Variability during Typhoon Events in Udo Rhodoliths Beach, Jeju Island, South Korea

    제주 우도 홍조단괴해빈의 태풍 시기 지형변화

    Woo-Seok Yoon, Seok-Hoon Yoon, Jae-Hong Moon and Ji-Seok Hong

    윤우석, 윤석훈, 문재홍, 홍지석

    Udo Rhodolith Beach is a small-scale, mixed sand-and-gravel beach embayed on the N–S trending rocky coast of Udo, Jeju Island, South Korea. … + READ MORE
    Udo Rhodolith Beach is a small-scale, mixed sand-and-gravel beach embayed on the N–S trending rocky coast of Udo, Jeju Island, South Korea. This study analyzes the short-term topographic changes of the beach during the extreme storm conditions of four typhoons from 2016 to 2020: Chaba (2016), Soulik (2018), Lingling (2019), and Maysak (2020). The analysis uses the topographic data of terrestrial LiDAR scanning and drone photogrammetry, aided by weather and oceanographic datasets of wind, wave, current and tide. The analysis suggests two contrasting features of alongshore topographic change depending on the typhoon pathway, although the intensity and duration of the storm conditions differed in each case. During the Soulik and Lingling events, which moved northward following the western sea of the Jeju Island, the northern part of the beach accreted while the southern part eroded. In contrast, the Chaba and Maysak events passed over the eastern sea of Jeju Island. The central part of the beach was then significantly eroded while sediments accumulated mainly at the northern and southern ends of the beach. Based on the wave and current measurements in the nearshore zone and computer simulations of the wave field, it was inferred that the observed topographic change of the beach after the storm events is related to the directions of the wind-driven current and wave propagation in the nearshore zone. The dominant direction of water movement was southeastward and northeastward when the typhoon pathway lay to the east or west of Jeju Island, respectively. As these enhanced waves and currents approached obliquely to the N-S trending coastline, the beach sediments were reworked and transported southward or northward mainly by longshore currents, which likely acts as a major control mechanism regarding alongshore topographic change with respect to Udo Rhodolith Beach. In contrast to the topographic change, the subaerial volume of the beach overall increased after all storms except for Maysak. The volume increase was attributed to the enhanced transport of onshore sediment under the combined effect of storm-induced long periodic waves and a strong residual component of the near-bottom current. In the Maysak event, the raised sea level during the spring tide probably enhanced the backshore erosion by storm waves, eventually causing sediment loss to the inland area. - COLLAPSE
    30 December 2021
  • Review

    Quality Control Methods for CTD Data Collected by Using Instrumented Marine Mammals : A Review and Case Study

    해양포유류 부착 CTD 관측 자료의 품질 관리 방법에 관한 고찰 및 사례 연구

    Seung-Tae Yoon and Won Young Lee

    윤승태, 이원영

    ‘Marine mammals-based observations’ refers to data acquisition activities from marine mammals by instrumenting CTD (Conductivity-Temperature-Depth) sensors on them for recording vertical profiles … + READ MORE
    ‘Marine mammals-based observations’ refers to data acquisition activities from marine mammals by instrumenting CTD (Conductivity-Temperature-Depth) sensors on them for recording vertical profiles of ocean variables such as temperature and salinity during animal diving. It is a novel data collecting platform that significantly improves our abilities in observing extreme environments such as the Southern Ocean with low cost compared to the other conventional methods. Furthermore, the system continues to create valuable information until sensors are detached, expanding data coverage in both space and time. Owing to these practical advantages, the marine mammals-based observations become popular to investigate ocean circulation changes in the Southern Ocean. Although these merits may bring us more opportunities to understand ocean changes, the data should be carefully qualified before we interpret it incorporating shipboard/autonomous vehicles/moored CTD data. In particular, we need to pay more attention to salinity correction due to the usage of an unpumped-CTD sensor tagged on marine mammals. In this article, we introduce quality control methods for the marine mammals-based CTD profiles that have been developed in recent studies. In addition, we discuss strategies of quality control specifically for the seal-tagging CTD profiles, successfully having been obtained near Terra Nova Bay, Ross Sea, Antarctica since February 2021. It is the Korea Polar Research Institute’s research initiative of animal-borne instruments monitoring in the region. We anticipate that this initiative would facilitate collaborative efforts among Polar physical oceanographers and even marine mammal behavior researchers to understand better rapid changes in marine environments in the warming world. - COLLAPSE
    30 December 2021
  • Review

    Trace Element in the Indian Ocean: Current Research Trends and Future Needs

    인도양에서 미량원소 연구 동향 및 향후 연구 방향

    Intae Kim

    김인태

    Trace elements in the ocean have been known as essential micronutrients for the primary production of phytoplankton and the growth of marine … + READ MORE
    Trace elements in the ocean have been known as essential micronutrients for the primary production of phytoplankton and the growth of marine organisms. The GEOTRACES program beginning in the mid-2000 provided a new understanding of the distribution, origin and behavior of trace elements in the ocean, together with the establishment of both clean seawater sampling and trace element analysis techniques. The Indian Ocean, one of the major oceans, is relatively the least explored area, despite playing an important role in global climate variability. Although trace element observations have recently been conducted in the Indian Ocean by Japanese-and Indian scientists, relatively not much study has been done compared to the Atlantic, Pacific and Polar Regions. Recently, together with the launch of R/V Isabu, a 5,000-ton grade large- and comprehensive research vessel, the observations of trace elements has been conducted in the Indian Ocean for the first time in Korea since 2018. In this paper, we introduce the key results of currently conducted GEOTRACES expedition in the Indian Ocean to present future trace element research directions in the Indian Ocean, and also reviewed the preliminary results in the Indian Ocean studies from Korea. In the 2020s, new Indian Ocean GEOTRACES projects are planned around European countries, and it is time for Korea to prepare for the next phase of the trace element study in the Indian Ocean in line with these international trends. - COLLAPSE
    30 December 2021
  • Review

    Domestic Research Trends on Fluorescent Dissolved Organic Matter in Marine Environment

    해양 환경의 형광용존유기물에 관한 국내 연구 동향

    Jeonghyun Kim

    김정현

    Fluorescent dissolved organic matter (FDOM) is referred to organic matter which absorbs efficiently solar radiation energy and fluorescence in the water column. … + READ MORE
    Fluorescent dissolved organic matter (FDOM) is referred to organic matter which absorbs efficiently solar radiation energy and fluorescence in the water column. The component and molecular structure of marine organic matter can be changed depending on the various substances and origins of organic matter, and then the organic matter has unique fluorescent properties. As the cutting-edge analytical techniques of optical measurement continuously developing from last few decades, a study on FDOM has been applied as a biogeochemical tracer to quantify the organic matter concentration and to investigate the behaviors and origins of organic matter. Especially, the marine environment around the Korean Peninsula is an ideal research area to study FDOM because of various oceanographic characteristics and the origins of organic matter. This study describes the general properties of FDOM and introduces the cycling and behaviors of marine organic matter based on the domestic research studies. - COLLAPSE
    30 December 2021
  • Note

    Pathology Survey of the Manila Clam Ruditapes philippinarum from Hwangdo Tidal Flat in Cheonsu Bay on the West Coast of Korea
    Hyun-Sung Yang, Young-Ghan Cho, Jong-Seop Shin, Heung-Sik Park and Kwang-Sik Choi
    Manila clam Ruditapes philippinarum is present at high rates of density in tidal flats in Cheonsu Bay on the west coast of … + READ MORE
    Manila clam Ruditapes philippinarum is present at high rates of density in tidal flats in Cheonsu Bay on the west coast of Korea, where clams often exhibit mass mortalities in late summer. We monitored the pathologic condition of clams at Hwangdo tidal flat (HD) to understand the parasitic impacts on clam fitness. Manila clams were fully ripe in July and spawned during August and September, as the histology indicated. The histology revealed that clams in HD tidal flats were heavily infected by the protozoa parasite Perkinsus olseni, as the monthly prevalence ranged from 53% (September) to 93% (August). In addition, Manila clams were co-infected by the metazoan parasite Cercaria tapetis and Parvatrema duboisi with the prevalence of 0-33% and 0-14%, respectively. Massive hemocyte infiltration and subsequent inflammation were commonly observed from the gills of P. olseni infected clams. Clusters of P. olseni trophozoites and heavy hemocyte infiltration were also observed from the female gonad, suggesting that P. olseni interferes with host gonad maturation. The larval trematode occupied almost the entire host gonad, resulting in gonad castration. In addition, Metacercaria of P. duboisi were observed from the subsurface of the mantle. Ray’s fluid thioglycollate medium assay (RFTM) indicated that clams collected in August and September contained approximately 4.0x106 P. olseni cells/g gills. Condition Index (CI) declined gradually from spring to early summer, and the decline in CI was interpreted as a consequence of the heavy parasitism, as the parasites drain the host’s net energy to be used in somatic growth and gamete production. - COLLAPSE
    30 December 2021
  • Data

    The Complete Mitochondrial Genome of the Fourhorn Sculpin Triglopsis quadricornis (Perciformes, Cottidae) from Sirius Passet, North Greenland
    Bo-Mi Kim, Ji-Hoon Kihm, and Tae-Yoon S. Park
    Triglopsis quadricornis Linnaeus, 1758 (Cottidae) is distributed in the Atlantic and Arctic and has four unique bony protuberances on its head. Here, … + READ MORE
    Triglopsis quadricornis Linnaeus, 1758 (Cottidae) is distributed in the Atlantic and Arctic and has four unique bony protuberances on its head. Here, we report the complete, circular, and annotated mitochondrial genome of T. quadricornis. The complete T. quadricornis mitochondrion was sequenced by high-throughput Illumina HiSeq platform. The sequences are 16,736 bp in size and contains 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, a control region, and large and small ribosomal subunits. The overall genomic structure of T. quadricornis mitochondrion was conserved with the gene arrangement of Megalocottus and Myoxocephalus species, and phylogenetic analysis supports their sister relationships. Most PCGs consist of TAA or TAG as a termination codon, whereas COII, ND4, and CYTB have T-- as a stop codon. This complete mitochondrial DNA information of T. quadricornis will provide an essential genomic resource to elucidate the phylogenetic relationship and evolutionary history of the family Cottidae. - COLLAPSE
    30 December 2021