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Semiautomated sedimentary type classification of seamounts in the Western Pacific using deep-sea camera images
No full textTo classify the sedimentary types of the seafloor, image analyses were performed on the deep-sea camera (DSC) images, including semantic segmentation, clustering, and grouping. Segmentation for the classification of sedimentary types was conducted using the random forest-based classifier provided by the Labkit plugin in Fiji, and then K-means clustering and grouping using gray-level co-occurrence matrix (GLCM) were performed. Sedimentary types were grouped into three clusters, and the average pixel ratio of the ferromanganese crust was approximately 0.75 in the ferromanganese dominant (Mn-dominant) type, approximately 0.35 in the mixed type, and approximately 0.11 in the sediment-dominant (S-dominant) type. The GLCM feature analysis of patches corresponding to ferromanganese crusts and sediments within the image showed that they were distinguished at a dissimilarity value of approximately 2. In addition, representative images selected for the Mn-dominant type and S-dominant type were distinguished at a dissimilarity value of approximately 0.7. These results are expected to suggest that image classification using pixel ratios and GLCM features has the potential to reduce subjective decisions by researchers and provide clearer classification criteria. Moreover, it is expected that these semi-automated processes can reduce researchers' efforts.11Nsciescopuskc
Modeling Desorption Rates and Background Concentrations of Heavy Metals Using a One-Dimensional Approach
No full textHarmful heavy metals (HHMs) in marine sediments pose significant ecological and human health risks. This research developed a novel one-dimensional mathematical model to investigate the desorption rates and background concentrations () of HHMs in cohesive sediments of coastal environments, using Cartagena Bay (CB), Colombia, as a reference for estuarine systems. The model integrates mass balance and molecular diffusion equations incorporating porosity and tortuosity. Both the particulate and dissolved phases of HHMs were considered. Numerical experiments were conducted over 28 years with a daily time step, simulating four primary hydrodynamic processes: molecular diffusion, desorption, sedimentation, and turbulent water exchange. The spatiotemporal evolution of provides valuable insights for sediment modeling, policy development, and advancing the understanding of HHM pollution in sediments. Results of the model align closely with empirical data from CB, demonstrating its applicability not only to local conditions but also to similar contaminated areas through a generalized approach. This model can be used as a reliable computational tool for managing coastal environments.11Ysciescopu
Radiological impact assessment of a hypothetical accident at the Zaporizhzhia nuclear power plant
No full textThe atmospheric dispersion of radioactive materials and the resulting radiation dose were assessed for a hypothetical accident at the Zaporizhzhia Nuclear Power Plant in Ukraine. The release quantities of 131I and 137Cs were assumed to be the same as those released into the atmosphere in the Chernobyl nuclear accident. The evaluation utilized atmospheric dispersion and dose assessment models, both of which are key components of the Radiological Accident Preparedness System in Korea (RAPS-K) developed by the Korea Atomic Energy Research Institute. Simulation results showed that radioactive plumes initially moved to the western across Europe, and later, some plumes were transported to the Asia due to westerly winds. Dose assessments revealed that effective radiation doses were showed above 1 mSv in certain areas near the Zaporizhzhia plant, while radiation exposure remained below 0.1 mSv across the rest of Europe, Asia, and North America. Especially, the thyroid dose due to 131I was presented about 19 mSv and 29 mSv, respectively in Kyiv and Odesa of Ukraine.11Nsciescopu
Insights into Quaternary iron fertilization dynamics in the western equatorial Pacific: Proxy archives offshore of northern Papua New Guinea
No full textThe equatorial Pacific is a key oceanographic region for unraveling Earth's climate system dynamics, where nutrient availability (e.g., iron, nitrogen, and phosphorus) plays a crucial role, at least partially, in governing the biologic pump and sea-air carbon exchange. Despite this, provenance, routing, and depositional processes, together with fertilization effects of nutrient supply to the western equatorial Pacific during the Quaternary, with Papua New Guinea potentially acting as a major iron contributor, remain elusive. Here, we present a comprehensive analysis of proxy archives for island erosion and weathering, terrestrial matter supply, surface ocean productivity, downward export of biogenic material, and bottom-water redox, all closely linked to orbital variations of iron fertilization, along the continental slope offshore of northern Papua New Guinea since 275 kyr. Our findings reveal a prominent precession cycle across these integrated records, aligning with changes in January–March insolation at 5°S. The observed temporal coupling indicates that heightened precipitation and erosion in northern Papua New Guinea stimulated nutrient input, thereby enhancing surface ocean fertilization, biologic production, and particulate carbon burial in the western equatorial Pacific during periods of high January–March insolation at 5°S. This caused the area to be a significant atmospheric CO2 sink during La Niña-like conditions. We propose that enhanced erosion in northern Papua New Guinea led to increased iron fertilization in the western equatorial Pacific. Ongoing iron fertilization may significantly mitigate anthropogenic global warming by enhancing atmospheric CO2 sequestration associated with increased occurrences of future consecutive La Niña events, as predicted by model simulations. © 202411Nsciescopu
A Vision-Based Quality Inspection System for Seafoods (Fishcakes, Oysters, Dried Lavers)
No full text수산식품 가공 산업의 생산성 향상 및 어가수 감소 및 고령화에 따른 인력 부족을 해결하기 하기 위하여 수산식품 가공 장비 및 자동화 기술의 적용이 시급한 상황이다. 최근 고도화된 머신 비전 및 인공지능 기술을 식품산업 분야에 적극적으로 도입하고 있는 실정으로 수산식품 가공 공정 내 인력의 육안 검사의 감각적인 평가에서 객관적인 품질 자동평가를 실현하는 스마트 검사 기술 개발에 수요가 증가하고 있다. 본 연구에서는 사각어묵, 굴 및 마른김과 같은 수산식품 가공 공정 내 적용가능한 비전영상 기반 자동 검사시스템을 개발하였다. 사각어묵 가공 공정의 경우, 공정 초기 연육 투입/배합 과정에서 연육 포장비닐과 탈유 과정의 교체시기가 임박한 탈유포 유입이 발생할 수 있어 영상검사를 통하여 두 이물질 유입여부 검사를 수행한다. 굴의 경우, 박신 후 세척/포장 단계의 굴껍질 유입을 검사한다. 마른김은 원재료인 물김과 함께 유입된 해양쓰레기 (그물, 스티로폼 등)와 포장 전 마른김 상태 (찢김, 구멍, 울림 등)에 대한 영상검사를 수행한다. 수산식품 가공 시 유입된 최소 3 mm크기의 이물질을 검출하기 위하여 이물질 유입 상황을 모사하여 세 품목의 학습 데이터셋을 측정하였으며 YOLO 객체 검출 모델을 적용하여 수산식품용 영상 검사 모델을 개발하였다. 개발된 수산식품 머신 비전 기술을 통하여 보다 객관적 검사데이터 기반 품질 관리를 수행할 것으로 기대된다.2
Microplastic transport from land to sea: The crucial role of rainfall events
No full textMicroplastics are widespread across various environmental matrices. Urban rivers represent a major pathway for land-based microplastics in the global oceans, however, studies on temporal variation and input characteristics of microplastics transported through rivers during rainfall events are limited. Herein, we investigated the emission characteristics of microplastics into Masan Bay transported through the Samhocheon (a stream flowing into Masan Bay), during a rainfall event with a rainfall depth exceeding 50 mm by applying time-weighted sampling. The abundance of microplastics ranged from 4.60 n/L to 118 n/L, with event mean concentrations (EMCs) of 29.9 n/L. The abundance of microplastics peaked in the early runoff stage and varied according to rainfall intensity during a rainfall event. Polypropylene and polyethylene were observed as the predominant polymers, accounting for around 60 % of total microplastics. Fragments were the dominant shape, and the most common size class was less than 200 μm. The total microplastic load discharged from an urban stream during a rainfall event was estimated to be 36.2 billion particles. Most microplastics were transported early (30% of runoff duration), while larger and heavier particles were carried later. In our previous study, the estimated annual microplastic load without considering rainfall events was 328 billion particles, contributing 22% of the total microplastic load entering Masan Bay through three land-based pathways: rivers, wastewater treatment plant effluent, and atmospheric deposition. However, during the rainfall events, the annual microplastic load increased approximately 30-fold to 10.7 trillion particles, and the contribution of rivers to the total microplastic load entering Masan Bay was estimated to rise to 90%. These findings suggest that microplastics transported during rainfall events play a significant role in land-to-sea microplastic emissions. Therefore, rainfall-induced runoff should be considered a critical factor when monitoring or modeling microplastic input through riverine pathways.2
Screening for new anti-viral compounds from marine-derived actinomycetes isolated from deep-sea sediments collected off Dokdo
No full textActinobacteria produce secondary metabolites, which are not indispensable for their growth and development but could provide an advantage of competition between organisms. Such secondary metabolites have several biological activities, such as antiviral, antibacterial, anti-tumor, and anti-inflammatory properties. Among them, some secondary metabolites with unusual structures and intensive biological activities could be promising sources for the development of new antiviral drugs. During our ongoing research for new secondary metabolites from marine microorganisms, we could isolate an Actinomadura geliboluensis 238DD-017 strain from a sediment sample collected at Dokdo, Republic of Korea in 2023. Four compounds, including two hybrid peptide–polyketide derivatives and two spirotetronate polyketides, were isolated from the crude extract of the culture broth of the strain. The structures of the compounds were determined by analyses of their MS and NMR spectroscopic data and these compounds were evaluated for their anti-viral activities.1
ENSO 선행 지표 가능성: 서태평양의 북적도해류 수송량
No full text북서태평양의 ENSO와 열대 해류 사이의 관계를 조사하기 위해 1993년 1월부터 2020년 5월까지의 월평균 재분석자료(GLORYS12V1)를 분석하였다. 재분석자료의 북적도해류(NEC) 재현성은 2017년부터 2020년까지 관측된 131°E 단면의 CTD와 ADCP 자료를 비교하여 확인하였다. NEC와 북적도반류(NECC)의 용적 수송량(VT)은 NEC와 NECC가 평균적으로 나타나는 위도(7.5°N<NEC<18.5°N, 3°N<NECC<7.5°N)에서 수심 300m까지의 유속으로 계산하였으며, 두 해류의 VT는 밀접한 상관관계가 있었다(r=0.67). 12개월 이동 평균한 NEC VTA는 Nino3.4 지수보다 6개월 앞서 변화했으며 상관 계수는 0.46이었습니다. 반면, NECC VTA는 Nino3.4 지수보다 4개월 앞서 변화했으며 상관 계수는 0.63이었습니다. 이것은 서태평양 131°E 단면의 NEC와 NECC는 2개월 시간 지연이 있으며, ENSO 신호에 반영된다는 것을 의미합니다. 이 결과는 NEC VTA가 ENSO의 선행 지표로 사용될 수 있음을 시사한다.2
AuxDepthNet: Real-Time Monocular 3D Object Detection with Depth-Sensitive Features
No full textMonocular 3D object detection is a challenging task in autonomous systems due to the lack of explicit depth information in single-view images. Existing methods often depend on external depth estimators or expensive sensors, which increase computational complexity and complicate integration into existing systems. To overcome these limitations, we propose AuxDepthNet, an efficient framework for real-time monocular 3D object detection that eliminates the reliance on external depth maps or pre-trained depth models. AuxDepthNet introduces two key components: the Auxiliary Depth Feature (ADF) module, which implicitly learns depth-sensitive features to improve spatial reasoning and computational efficiency, and the Depth Position Mapping (DPM) module, which embeds depth positional information directly into the detection process to enable accurate object localization and 3D bounding box regression. Leveraging the DepthFusion Transformer (DFT) architecture, AuxDepthNet globally integrates visual and depth-sensitive features through depth-guided interactions, ensuring robust and efficient detection. Extensive experiments on the KITTI dataset show that AuxDepthNet achieves state-of-the-art performance, with AP3D scores of 24.72% (Easy), 18.63% (Moderate), and 15.31% (Hard), and APBEV scores of 34.11% (Easy), 25.18% (Moderate), and 21.90% (Hard) at an IoU threshold of 0.7.11Ysciescopu
Aestuariibius violaceus sp. nov., isolated from a marine limpet Cellana toreuma
No full textA novel bacterium, designated strain 2305UL40-4T, was isolated from Cellana toreuma (a Korean limpet) collected from Ulleung Island, Republic of Korea. The cells were Gram-stain-negative, aerobic, rod-shaped (0.5–0.9 µm×1.5–2.2 µm) and non-motile. Growth was observed at 22–36 °C (optimum 25–30 °C), pH 6–8 (optimum pH 7) and in the presence of 0.5–4.0% (w/v, optimum 2.0%) NaCl. The 16S rRNA gene sequence analysis revealed that strain 2305UL40-4T shared 97.4% similarity with Aestuariibius insulae DBTF-13T. The average nucleotide identity value between the two strains was 76.5%, and the digital DNA–DNA hybridization value was 19.0%. Both values are well below the species delineation thresholds. The DNA G+C content of strain 2305UL40-4T was 63.8 mol%. The major fatty acids were C16 : 0, C18 : 0 and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). Major polar lipids included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, five unidentified aminolipids and fifteen unidentified lipids. Ubiquinone-10 was the predominant quinone. The new strain differs from A. insulae in its ability to utilize d-raffinose, d-ribose and d-xylose. Based on these polyphasic taxonomic characteristics, strain 2305UL40-4T is proposed as a novel species within the genus Aestuariibius, with the name Aestuariibius violaceus sp. nov. The type strain is 2305UL40-4T (=KCCM 43505T=MCCC 1K09164T).11Nsciescopu