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Interpretation of Long-Term Fishing Activity Changes using DNB Night Light Satellites Data
No full textVIIRS (Visible Infrared Imaging Radiometer Suite) 센서의 DNB (Day and Night Band)는 야간 조업 선박 탐지에 효과적인 위성 데이터로, EOG (Eearth Observation Group)에서는 위성 데이터를 이용해 VBD (VIIRS Boat Detection) 자료를 제공하고 있다. 본 연구는 불법어업 (IUU) 선박의 감시 및 대응을 위한 한국-태도국 프로젝트의 일환으로 장기간 야간 조업 선박 탐지 결과를 이용해 태평양 도서국들(Pacific Islands)의 어업활동의 변동 특성을 해석하고자 한다. 공간적 변동은 태평양 도서국은 15개국의 EEZ (Exclusive Economic Zone)를 고려해 국가별 어업활동을 선박 척수, 밀집도 기반으로 분석하였다. 시간적 변동은 2016년부터 2024년까지 장기간의 자료 기반으로 일, 월, 계절별 분석과 국가별 및 공간별 특징을 복합적으로 고려해 분석하였다. 본 연구는 태평양 도서국에서 발생하는 불법 어업의 경향 파악에 도움이 될 것으로 판단 된다.2
Investigating hydrodynamic factors contributing to sea desertification along the east sea coast of Republic of Korea
No full textThe recent expansion of sea desertification along the East Sea coastal region has led to the decline of natural seaweed beds, raising concerns about economic losses due to the loss of spawning and nursery grounds for fish and shellfish, as well as the reduction of critical ecological functions. In response to this issue, the Korea Institute of Ocean Science and Technology (KIOST) has initiated research to identify the factors contributing to sea desertification. As part of this effort, in-situ verification technology is being developed to investigate the physical drivers of sea desertification. This study focuses on two key areas: (1) elucidating the hydrodynamic characteristics around seaweed habitats and (2) reconstructing historical sea surface temperature changes using a numerical modeling system. To analyze the hydrodynamic properties of macroalgal habitats, field surveys were conducted annually from 2022 to 2024 in the coastal waters near Hujeong Beach. In 2023, wave observations indicated that the maximum significant wave height reached 1.33 m, with no storm waves detected. More than 87% of the observation period recorded wave heights below 1 m, indicating a relatively low-energy environment. However, during the second survey, significant wave heights exceeding 2 m were recorded, revealing meaningful differences in wave energy. In the third survey, turbulence structures induced by macroalgae were observed to change with wave direction, resulting in increased turbulent kinetic energy. Notably, when fluctuations in significant wave height and direction were large, both turbulent kinetic energy and Reynolds shear stress were
found to be higher near the seabed under macroalgal habitat conditions. The hydrodynamic data obtained from this study will serve as validation data for a high-resolution turbulence model currently being developed, ultimately providing insights into how hydrodynamic
characteristics influence macroalgal growth and distribution patterns.1
Detection of seaweed forests using image and acoustic data
No full textThis study explores the detection of seaweed forests using various image and acoustic datasets(satellite images, water column and backscatter images derived from multibeam sonar, multispectral drone images, and underwater images). The study was conducted near the
submerged breakwater at Hooam Beach, Uljin, in the central East Sea, where seaweed vegetation is abundant.
Satellite images were used to classify seaweed distribution on a broad scale by analyzing spectral characteristics. To improve classification accuracy, optimized atmospheric correction and filtering techniques were applied.
Multispectral drone images were analyzed using representative reflectance values. Seaweed was clearly visible in May 2022 but was absent in November 2023 and October 2024. Underwater images were captured at approximately 50-meter intervals to assess the seaweed
forest status. A labeling process was performed for artificial intelligence-based classification.
Water column images derived from multibeam sonar provided more direct and detailed seaweed detection than satellite imagery in waters deeper than 5 meters. Analysis of data from 2022 to 2024 showed seaweed presence in 2022 and 2024 but absence in 2023. The detected
seaweed was mainly found on rocky outcrops at depths of around 10 meters, resembling Sargassum species with lengths of 2 to 4 meters.
Backscatter images based on multibeam bathymetry were used to map seabed environments and analyze frequency-dependent backscatter intensity. The study area contains 4 distinct seabed types, with seaweed primarily distributed on rocky substrates and sandy sediment
layers. Multi-frequency scan angle response analysis showed that in rocky areas, seaweed had high diffuse reflectance with a strong response at 300 kHz, while in silty-sandy areas, backscatter intensity was slightly lower at 400 kHz.
This study demonstrates the effectiveness of integrating multiple image and acoustic data techniques for seaweed forest detection and habitat analysis, contributing to improved marine ecosystem monitoring.1
황해 퇴적물에서 영양염과 메탄 플럭스
No full text박스 코어를 사용하여 황해 해역에서 퇴적물을 채집한 후, 퇴적물 챔버 배양 실험을 위한 부시료를 채취하였다. 퇴적물 산소소모율, 영양염 플럭스 및 메탄 플럭스를 분석하기 위해 퇴적물 배양 실험을 수행하였는데, 퇴적물 챔버 배양 실험은 총 8개 정점에서 진행되었으며, 약 120시간(5일) 동안 배양을 하였다. 모든 정점의 퇴적물은 미세한 입자의 뻘질 퇴적물로, 유기탄소 함량은 0.6%에서 1.2% 사이였고, C/N 비율은 7에서 10 사이로 대부분 해양기원성 유기물로 추정된다. 퇴적물 산소소모율은 0.9 mmol/m²/day¹ ~ 4.0 mmol/m²/day¹범위였으며, 이는 연안해역 퇴적물의 산소소모율에 비해 상대적으로 낮았다. 각 정점에서 질산염 플럭스는 다른 양상을 보였는데 대부분 정점에서는 지산염이 감소하였으나 일부 정점에서는 증가하였다. A08, P13, D03, B03, Z4-03 정점에서는 각각 –44, –51, -44, -107, -49 μmol/m²/day¹의 플럭스를 보였고, 반면 A05, G06, A03 정점에서는 각각 38, 8.6, 20 μmol/m²/day¹로 증가하는 플럭스를 보였다. P13과 D03 정점에서는 인산염이 소비되어 각각 –11, -5 μmol/m²/day¹였고, A08, A05, G06, A03, B03, Z4-03 정점에서는 각각 25, 27, 32, 14, 4, 43 μmol/m²/day¹의 플럭스를 보였다. A08 사이트에서는 초기에는 퇴적물에서 질산염이 유출되었으나 시간이 지나면서 질산염이 급격히 감소하여 물속에서 소비된 것으로 추정된다. P13 사이트는 다른 사이트에 비해 산소 소비율이 상대적으로 낮았으며, 퇴적물의 표층에서 유기물이 계속 분해되면서 질산염과 인산염이 생성된 것으로 판단된다. 메탄 플럭스는 A08, P13, A03, D03 정점에서 각각 0.458, 0.056, 0.042, 0.023 μmol/m²/day¹로 매우 적은 양의 메탄이 수층으로 용출되었다. B03, Z4-03 정점에서는 각각2.91, 5.29 μmol/m²/day¹로 다른 정점에 비해 상대적으로 높은 메탄 플럭스를 보였다. 일부 정점에서는 메탄의 용출이 검출되지 않았다. 120시간의 퇴적물 배양 후에는 산소 농도의 변화가 거의 나타나지 않았고, 메탄의 용출도 매우 낮은 농도로만 발생하였다.2
독도연구 25년, 그 활동과 성과
No full text독도연구 25년, 그 활동과 성과
한국해양과학기술원은 1999년과 2004년 해양수산부 단년도 독도연구과제 수행에 이어 2006년부터는 국가 독도 법률과 기본계획에 의거하여 2024년까지 25년여에 걸쳐 장기사업을 수행해 왔다. 본 저자는 정부로부터 독도사업과 독도연구조직을 확보하고 이끌어 오면서 독도영토에 대한 다각적이고 전방위적 신 자료정보 확보와 새로운 발견 및 결과의 활용연구를 통해서 독도의 가치를 높이고 강력한 과학주도 독도 주권행사에 기여해 왔다.
독도연구에는 이사부호 등 많은 연구선과 심해 잠수정 해미래, 위성, 항공기, 드론, 관측부이 등 다양한 가용연구관측 수단이 동원되었다. 독도탄생의 비밀을 밝혀내는 것부터 심해까지의 독도 해양영토를 지도화하고 환경, 생태, 생물, 지질, 자원 등 독도와 주변 해양에 대한 다각적이고 전방위적 연구를 수행해 왔으며 그 성과를 다각적 홍보, 4D체험시스템, 영상체험물 등 독도의 실체적 접근 및 체험 수단들의 개발과 전파, 학술논문, 학술행사, 전시회, 강연, 교육, 각종 출판물을 통해 국민들과 함께 해 왔다.
주요 연구내용은 독도의 지형과 지질연구와 독도-울릉도 형성기원 및 변동 연구, 독도 주변해역 환경 및 생태계 모니터링과 진단, 독도 연안 환경변화에 따른 생태계 및 생물 영향 연구, 독도 연안 서식지 장기생태모니터링, 독도 수중생태지도 및 VR 수중 경관도 작성, 독도 해역 생물다양성 및 생물활용 연구, 독도 해양생태계 모델링 및 계절 예측 서비스, 독도 데이터베이스 구축·관리 및 독도종합정보시스템 운영, AI융합 독도 빅데이터 활용 연구, 데이터로 본 독도 바다 시리즈 등 각종 서적 발간 등 기초부터 AI 같은 현재 최신의 과학기술 적용 연구까지 망라하고 있다.
한편으로는 독도 영토관리와 지속가능 이용 및 독도에 대한 영유권 공고화와 국가 및 지자체의 주요 독도정책수립에 기여해 왔다.
독도 연구성과 및 확산실적은 총 3,000여건에 달하고 있다. 독도 학술 논문 및 학술발표 430여건, 언론홍보 1,300여건, 대국민 독도자료정보서비스 300여건 독도 연구현장 방문 등 대국민 독도이해 및 독도체험서비스(견학 및 방문) 840여건, 독도 관련 화보집, 생태지도, 총서, 아틀라스 등 서적 제작 배포 48건, 국ㆍ내외 특허 30여건, 워크숍, 세미나, 심포지엄 등 학술행사 360여건, 전시회 및 대중강연 등 독도지식정보 전파 150여건 등이다.
독도 국가데이터베이스와 독도종합정보시스템을 통해서는 독도에 대한 많은 자료정보와 연구성과들을 서비스하고 있다. 독도에 대한 방대한 성과들은 독도전문연구센터 주도하에 울릉도·독도해양연구기지를 비롯하여 한국해양과학기술원 본분원 및 전국 산·학·연 등 매년 최대 50개 연구팀 100여명, 연인원 2000여 연구진이 혼연일체가 되어 이루어낸 우리의 자부심이다. 우리는 독도를 통한 해양과학적 발전을 도모하고 독도영토의 실체 파악과 독도의 지속가능이용관리 및 영토주권 공고화를 위한 과학적 역할을 계속해 나갈 것이다.2
SEDIMENTOLOGICAL CHARACTERISTICS AND ENVIRONMENTAL CHANGES IN THE TIDAL FLATS OF GOMSO BAY, KOREA: A TEXTURAL AND HYDRODYNAMIC ANALYSIS
No full textGomso Bay, located on central Korea’s west coast, is a funnel-shaped bay approximately 4–6 km wide and 20 km long. The bay features well-developed microenvironments, including tidal flats, channels, creeks, and cheniers. According to the Digital Elevation Model (DEM) of Gomso Bay, a primary tidal channel is well-developed along the northern coast, and the tidal flat elevation within the bay is relatively higher than in the central and entrance regions. Over the past 30 years, sedimentary changes in the intertidal zones of the bay have been observed. The silt and clay content at the bay entrance has decreased while sand content has increased. In contrast, the middle and upper intertidal zones have experienced a decline in both sand and clay content, with a corresponding increase in silt. These sedimentary changes reflect dynamic shifts in the depositional environment, best interpreted through detailed analyses of grain size distribution in contemporary sediment facies. This study uses various classification methods to analyze the grain size characteristics of surface sediments in the tidal flats of Gomso Bay during the autumn seasons of 2023 and 2024. The observed trends in sediment grain size—including coarsening of the graphic mean size (MZ) and improved sorting (σ1) from the seaward to the landward areas indicate progressively decreasing energy conditions toward the landward side. Additionally, the sediment classification method based on a 0.5 Φ (phi) scale provided a more nuanced understanding of surface sediment characteristics than traditional classifications by Folk (1954) and Folk and Ward (1957). Future investigations into the characteristics of surface sediments should include sediment influx patterns, erosion and deposition dynamics, biological factors, and mineral composition to develop a comprehensive understanding of the evolving depositional environment of Gomso Bay.1
Evolutionary history of the Pohang Basin reconstructed from offshore seismic and deep-drilled core data: evidence for an early Miocene multi-directional sediment-feeding system and late Miocene trough fills
No full textThe Pohang Basin is a Miocene basin located in the southeastern part of the Korean Peninsula and is one of the most intensively investigated. However, due to the absence of offshore deep-drilled core data, including basement rock, and the difficulties in onshore-offshore stratigraphic correlation, the initial stage of the basin formation and the entire sedimentary succession remain poorly understood. This study integrates newly acquired seismic profiles and deep-drilled core data to refine the depositional history and basin evolution of the offshore Pohang Basin in southeastern Korea. Core analysis revealed 18 sedimentary facies, grouped into five facies associations (FAs): FA1 (fluvial), FA2 (lacustrine), FA3 (delta), FA4 (inner- to mid-shelf), and FA5 (outer shelf to basin plain). The seismic profiles were divided into five major depositional units (Units I–V) based on the lap-out patterns and acoustic characteristics. The basal part of the drilled core comprises coarse-grained deposits of fluvial to deltaic origin, containing angular to subangular, poorly sorted dacitic to andesitic volcanic clasts. Additionally, time structure and isopach maps show that the initial succession (Unit I) was predominantly sourced from the south and east, in contrast to the prevailing interpretation that attributes the sediment supply to the western fan-delta system. These findings suggest that the basin was affected by multi-directional sediment feeding systems during its initial deposition. Based on the palynological assemblages and Sr isotope dating of drilled core samples, the top part of the depositional units was assigned to the middle Miocene. However, the presence of a thick trough fill, characterized by growth strata and compressional anticlines in a seismic record, suggests localized and continuous deposition, potentially extending into the late Miocene. This integrated approach refines previous basin development models by highlighting the multi-directional sediment feeding systems and structural complexity in basin infills.11Nsciescopuskc
Control and Real-Time Monitoring of Autonomous Underwater Vehicle Through Underwater Wireless Optical Communication
No full textReal-time command and data transfer are essential for autonomous underwater vehicle (AUV) motion control in underwater missions. Due to the limitations of underwater acoustic communication, which has a low data rate, this paper introduces a new control structure using underwater wireless optical communication (UWOC) to enable effective real-time command and data transfer. In this control structure, control inputs for the AUV attitude from outside of the water are transferred to the AUV for motion control, while its orientation data and visual images from the AUV camera are sent to the control station outside the water via the UWOC system. For demonstrating the performance of control action and data monitoring, an AUV is built with a constructed UWOC system, two vertical thrusters, and two horizontal thrusters. For attitude control of the AUV, an attitude heading reference system (AHRS) and a depth sensor are installed. Bi-directional communication in the UWOC system is achieved using a return-to-zero (RZ) modulation scheme for faster, longer-range data transfer. A signal processor converts sensor data received from the transmitted data. Finally, the hovering control performance of the AUV equipped with the UWOC system was experimentally evaluated in a water tank, achieving average root mean square errors (RMSEs) of 4.82 degrees in roll, 2.49 degrees in pitch, and 1.99 mm in depth, while simultaneously transmitting real-time motion data at 21.2 FPS with VGA-resolution images (640 x 480 pixels) at a communication rate of 1 Mbps.11Nsciescopu
Rapid detection of three IMO standard marine bacteria using recombinase polymerase amplification and lateral flow assay (RPA-LFA)
No full textThe Convention on the International Maritime Organization (IMO), the presence of Escherichia coli, intestinal Enterococcus spp., and toxigenic Vibrio cholerae in the ballast water, prior to disposal, indicates the existence of microbes. However, current testing processes for controlling marine bacteria pathogens either require too much equipment or are too time-consuming. To improve the testing process, a combination of Recombinase Polymerase Amplification (RPA) and a Lateral Flow Assay (LFA) was used to detect V. cholera and two species of Enterococcus (E. faecalis and E. faecium) in ballast water in this study. These results showed the successful development of an RPA-LFA method for detecting V. cholera, E. faecalis and E. faecium. A variety of temperatures (30–50°C) and incubation durations (0–30 min) were investigated. Optimal results were attained at 37°C for 20 min, with lateral flow dipsticks detecting within 5–10 min and allowing diagnosis in roughly 1 h without advanced tools. This detection method is suitable for use in the on-site diagnosis also it has high specificity and is quick to use.33Nscopu
Genetic diversity and seascape population structure in eelgrass (Zostera marina) meadows in the northwestern Pacific
No full textSeagrasses, the only flowering plants in the ocean, provide numerous, but crucial ecosystem services for coastal and estuarine environments. Yet, natural seagrass populations have been continuously declining worldwide due to ongoing climate change and accelerating anthropogenic influences. To make conservation efforts for effectively managing and preserving local seagrass populations, an understanding of their genetic diversity and population structure is essential. In the present study, using seven microsatellites we assessed the current population genetic status and phylogenetic relationships of Zostera marina, the predominant seagrass species in the northwestern Pacific, on the entire coasts of the Korean Peninsula and Jeju Island and also the northeastern China and southwestern/northern Japan. Results of genetic diversity analysis revealed that Jeju Island populations display the higher degree of asexual reproduction, as indicated by a lower level of clonal diversity, and thus significantly reduced genetic diversity than any other coastal regions. Genetic population structure tended to be grouped into corresponding coastal regions, although two genetic clusters are the most likely, which can be attributed to limited contemporary gene flow occurring among the regional populations. Jeju Island population has a unique genetic composition in reference to the other sea areas, and the possibility of local extinction may be the highest due to the depleted genetic diversity as well as strong genetic differentiation. Our study provides fundamental information on the eelgrass’s genetic diversity and spatial population structure over the northwestern Pacific, which helps to make restoration efforts, including transplantation projects, particularly for the Jeju Island population.11Nsciescopu