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Species Distribution Model-based Habitat Change Projections of the Kelp Species, Ecklonia cava under SSP Scenarios
No full textThe main kelp forest-forming alga Ecklonia cava (E. cava), plays an important role in coastal ecosystems of South Korea. Despite this coastal ecological importance, there is a lack of research on the prediction of macroalgal distribution. In this study, we examined the distribution of E. cava recorded since 1955 and predicted distribution changes starting from 2000, under different climate change scenarios (SSP1-1.9 and SSP5-8.5) using the species distribution model (MAXENT). It reported that E. cava has expanded its range to 38°N latitude since 2000. We found seawater temperature, primary productivity and seawater velocity were controlling factors that determine the habitat of E. cava. Under the low emissions scenario (SSP1-1.9), the habitat suitability and distribution of suitable habitats did not show significant changes. While, under the high emissions scenario (SSP5-8.5), a decline in the southern distribution and an expansion of the northern distribution was predicted. In particular, most of the current habitats of E. cava were found to have decreased habitat suitability, thus the existing population of the species in South Korea may experience a sharp decline. The results of this study can be used as a basis for developing sustainable conservation measures to maintain coastal ecosystems of rocky shore in South Korea.22Nkc
Evaluation of the diagnostic reliability of the gill-based Ray’s fluid thioglycollate medium assay for Perkinsus olseni infections in Manila clams (Ruditapes philippinarum) across Korean tidal flats
No full textThe alveolate protozoan parasite Perkinsus olseni infects a range of marine bivalves inhabiting tidal flats and shallow subtidal zones, causing considerable damage to shellfish industries. Infection by P. olseni is typically assessed using Ray’s fluid thioglycollate medium (RFTM) assay, with gill tissue often employed as a diagnostic proxy for whole-body infection. However, the diagnostic reliability of gill-based assays across diverse ecological settings—particularly under low-infection conditions—remains uncertain. In this study, we investigated tissue-specific distribution and the diagnostic performance of the RFTM assay in detecting P. olseni in Manila clams (Ruditapes philippinarum) collected from 6 tidal flats along Korea’s west and south coast. The assay was applied to 6 different tissues, including gills and visceral mass. Infection prevalence reached 100% at most sites, except at Padori (90%). Whole-body infection intensity ranged from 0.1×104 to 3.7×106 cells per gram of tissue. The visceral mass consistently harbored the largest proportion of parasites (27.8%–49.0%), followed by the mantle (17.4%–30.6%) and gills (19.4%–25.2%). Gill infection levels correlated strongly with whole-body infection intensity (r2=0.6–0.95), supporting their diagnostic value in high-infection areas. However, at Padori—where infection levels were lowest—the efficacy of the gill assay dropped to 56%, resulting in a 44% false negative rate. These results underscore the limitations of relying solely on gill tissue in low-infection environments and highlight the need for a context-dependent diagnostic approach. A dual-tissue strategy incorporating both gill and whole-body samples is recommended to improve diagnostic accuracy in P. olseni surveillance of Manila clam populations.11Nsciescopuskc
Observation data for Rhincodon typus
No full textThis dataset contains 34 verified presence records of whale sharks (Rhincodon typus) in Korean waters between 2004 and 2024, compiled from domestic news reports. These reports documented sightings and incidental captures of whale sharks by fishers or the public.
As precise geographic coordinates were not provided in the reports, I estimated the approximate locations based on descriptive information (e.g., distances and directions from known landmarks). For instance, if a report indicated a sighting “3.5 km northeast of Daejin Port,” I projected a straight line at a 45-degree bearing from Daejin Port using Google Maps and marked the corresponding location
Meiofaunal Biofouling on the Marine Plastic Debris Washed Ashore in Polluted-Hot-Spots of Korea in Summer
No full text2021년 하계(8-9월)에 해안 쓰레기 밀집 해역에서 채집한 해양 플라스틱 쓰레기에 서식하는 중형저서부착생물(40-1,000 ㎛)의 부착 특성과 채집지역 간 차이를 조사하였다. 총 6종류의 플라스틱 쓰레기(밧줄, 스티로폼 부이, 페트병, 플라스틱 용기, 플라스틱 봉지, 스폰지)가 채집되어 6가지 재질(PP, PS, PET, LDPE, HDPE, EPS)로 구분되었고, 10개 생물분류군이 출현하였다. 모든 플라스틱 쓰레기의 표면적과 출현한 생물 개체수 간의 관계는 통계적으로 유의하지 않았다(r2=0.02, n=24, p=0.48). 반면, 표면적이 가장 작은 PP재질의 쓰레기에서 가장 높은 개체수가 관찰되었다(체 크기 40-60 ㎛: 68 inds./0.1 ㎡, 60-300 ㎛: 376 inds./0.1 ㎡, 300-1,000 ㎛: 489 inds./0.1 ㎡). 가장 작은 크기그룹(체 크기 40-60 ㎛)의 개체수가 재질별 유의한 차이를 나타낸 반면(F=6.693, p 0.05). 주요 우점분류군은 선충류가 가장 작은 크기그룹(체 크기 40-60 ㎛)에서 가장 우점했고(평균 77.8%), 다른 크기그룹(체 크기 60-300 ㎛, 300-1,000 ㎛)에서는 태형동물, 유공충류, 이매패류와 복족류가 우점하였다. 모든 크기그룹에서 출현한 평균 개체수는 염분이 가장 낮은(0.2 psu) 명지(249 inds./0.1 ㎡)와 흥남해수욕장(482 inds./0.1 ㎡)에서 다른 해역(65 inds./0.1 ㎡)에 비해 높았으나, 채집 해역간 유의한 차이는 없었다(p > 0.05). 요약하면, 하계 중형저서부착생물의 출현개체수가 쓰레기의 면적보다 특정 재질(PP)과 관련이 있고, 선충류가 우점한 크기그룹(체 크기 40-60 ㎛)이 재질별 차이를 나타낸 것으로 보아, PP재질의 쓰레기가 선충류의 유리한 서식환경일 수 있음을 시사한다.22Nkc
The Detailed Design of Underwater Platform Structure
No full textFor the detailed design of underwater platform structure, the relevant design criteria were identified and the applied loads were reviewed. Next, the detailed design methodology for platform structure was established, and the design method for large-diameter and small-diameter openings was determined. The structural safety was reviewed through structural analysis by incorporating large-diameter openings, and the structural reviews were conducted for small-diameter openings such as piping. In addition, the detailed design of inner deck was performed and the center of gravity of platform was calculated. Based on the reviewed detailed design plan, a detailed design ensuring structural safety was proposed. It is anticipated that the final detailed design should be completed through further consultation with the design teams of piping
systems, chambers, air quality management systems, and internal spaces.2
Validation of Simulation Models of Radioactivity Inspection System for Seafood Using Dried Laver
No full text국내 기관들에서는 안전한 먹거리 확보를 위해 수산물 도매시장을 대상으로 수산물 내 방사능 검사를 시행하고 있다. 하지만 특정 품목만을 샘플링하여 전처리 후 오랜 시간 측정하므로 전수검사가 불가능하며 경매가 모두 완료된 후에야 결과를 확인할 수 있다는 한계가 있다. 이에 본 연구진은 MCNP 전산모사 코드를 이용하여 식품의 원형을 보존하면서 식품 내 방사성물질 관리기준(I-131, Cs-134+Cs-137 각각 100 Bq/kg) 초과 여부를 신속하게 판단할 수 있는 방사능 검사장치(Rapid Seafood Radioactivity Inspection System, RS-RIS)를 설계한 바 있다. 개발된 장치는 PVT와 NaI(Tl) 섬광체를 각각 적용한 두 종류이며, 비교적 면적이 넓은 PVT (80× 50× 5 cm3) 검출기를 적용한 검사장치는 Cs-134를 측정할 수 없다는 단점이 있지만 검출효율이 높아 더 적은 양의 방사성물질까지 측정할 수 있다. 반면 NaI(Tl) 섬광체(40× 10× 5 cm3)를 적용한 검사장치는 PVT 기반 검사장치에 비해 검출효율은 낮지만 핵종판별이 가능하여 식품에 대한 관심핵종인 I-131, Cs-137, Cs-134를 모두 측정할 수 있다. 본 연구에서는 RS-RIS 프로토타입 장비와 테스트 대상으로 선정된 마른김을 이용하여 현장실증실험을 수행하고, 실험조건과 동일하게 모델링하여 얻은 전산모사 결과와 실험 결과를 비교하여 전산모사 모델의 신뢰성을 검증하였다. 실험에서는 Cs-137 점선원(18.22 μCi)을 사용하였으며, 마른김 내 다양한 위치에서 측정한 계수율을 전산모사 결과를 비교하였다. Cs-137의 관심영역에 대해 PVT와 NaI(Tl) 기반 장치 모두, 모든 측정 위치에서 실험값 대비 차이가 5% 이내를 나타내어 전산모사 모델을 신뢰도를 검증하였다.2
Vision-based Control of Robotic Arm mounted on Unmanned Surface Vehicle for Rocket Recovery
No full textUnmanned surface vehicles (USVs) equipped with robotic arms can perform various complex tasks such as grasping, sampling, and infrastructure repair. USVs are widely used for environmental monitoring, search and rescue missions, maintenance and repair, marine exploration, and its commercial applications. This paper presents an innovative vision-based strategy that utilizes a manipulator integrated with a USV to recover vertical takeoff vertical landing rockets in oceanic environments. This study focuses on a 4.3-m-long, 150-kg, three degree-of-freedom (DOF) WAM-V14 with a four-DOF manipulator. To detect and localize the landing rockets, a depth camera sensor and an advanced You Only Look Once Version Eight (YOLOv8) object-detection algorithm were employed. To train the YOLO algorithm, a customized bespoke dataset was developed for rocket identification. As the rocket descends and hovers, the system estimates its orientation and distance using a trained model. The measured distance served as the desired trajectory for the controller, thus guiding the USV toward the identified rocket and controlling the manipulator to reach its location. The integration of camera sensors, robotic arm manipulation, autonomous navigation, YOLO-based object detection, and a sliding-mode control system is promising for realizing affordable and safe rocket recovery operations in challenging oceanic environments.11Ysciescopu
Enhancing Detefction of Nighttime Shing Boat Lignht Using Viirs Satellite dasta and Deep Neural Networks
No full textIn recent years, illegal fishing activities in international oceans have caused numerous problems, becoming a significant issue in maritime areas. Detecting and penalizing illegal fishing vessels at night is more challenging because they deactivate their Automatic Identification System (AIS) transmitters. The Day/Night Band (DNB) data from the Visible Infrared Imaging Radiometer Suite (VIIRS) on the S-NPP and its successor, NOAA-20, can be used to detect low-light conditions. Therefore, this study introduces a deep neural network (DNN)-based model that utilizes DNB data to effectively detect nighttime fishing boat lights, thereby enhancing detection methods. This study explores using of VIIRS DNB data to detect illegal fishing activities, addressing the challenge of monitoring large ocean areas. By employing a DNN model to extract light from fishing vessels, you aim to overcome the limitations of AIS, which can be deactivated by illegal vessels. The model shows high accuracy, with a F1-score of 0.9.1
