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Comparison of Coastal Debris Interpretability Across Different GSD Levels in Drone Imagery
No full textRecent studies have increasingly utilized drones for remote sensing, driven by the widespread distribution of marine debris along coastal areas. When monitoring coastal debris using drones, flight altitude is a critical factor that directly impacts both the quality of image data and the monitoring duration. However, designing monitoring systems based solely on altitude may lead to variations in spatial resolution (GSD) caused by differences in camera specifications across various drone models. Such variations in GSD levels impact the interpretability of debris within the imagery. This study evaluates the interpretability of coastal debris at different GSD levels determined by drone specifications and flight altitudes. Based on prior studies, we collected data at four altitudes by GSD: 18.6 m (GSD: 0.5 cm/pixel), 27.9 m (GSD: 0.75 cm/pixel), 37.2 m (GSD: 1.0 cm/pixel), and 46.5 m (GSD: 1.25 cm/pixel). Coastal debris types were categorized into eight classes, defined based on the top 10 most frequently identified debris types over a four-year period in Korea. We also assessed the quality and interpretability of coastal debris data under varying spatial resolutions of drone imagery, with a particular focus on the eight defined categories. Interpretability was assessed based on the National Image Interpretability Rating Scales (NIIRS), developed by Image Intelligence, which defines four interpretability levels: I (Identify), B (Distinguish), D (Detect), and N (Not Detect). The results demonstrated that the interpretability of coastal debris varies depending on debris type, color, and size with changes in GSD. Furthermore, the detectable categories of debris were defined for each GSD level. Through this study, it is expected to support decisions on appropriate GSD settings and monitoring methods for different coastal debris survey objectives and conditions. The findings may also help in developing national policies for managing coastal debris.1
Protocol for efficient recovery of high- quality DNA from microbiome of marine invertebrates
No full textMarine organisms often form symbiotic relationships with various microorganisms to adapt and thrive in harsh environments. These symbiotic microbes contribute to host survival by providing nutrition, modulating the hosts’ immune system, and supporting overall physiological stability. Advances in high-throughput sequencing technologies have enabled a deeper understanding of the structure and function of symbiotic microbial communities, as well as host-microbe interactions. Notably, symbiotic bacteria associated with marine invertebrates such as corals and sponges are recognized as a potential source of useful bioactive compounds, including antibiotics and enzymes. However, obtaining high-quality microbial DNA from host tissues still remains a technical challenge due to the presence of unknown substances. This study focuses on optimizing sample preparation and DNA extraction procedures and additional purification to improve the recovery of microbial DNA while minimizing host DNA contamination. Comparison between several methods was conducted using sponge samples to evaluate DNA quality and microbial recovery. A sample designated as 2110BU-001 was collected from the east coast of the Republic of Korea and used for culture-independent microbial cell isolation. Total bacterial DNA was extracted by using a manual Phenol-Chloroform protocol and three commercial kits. DNA extracted using the standard manual method showed both the highest yield and the largest fragment size. However, PCR (Polymerase chain reaction) test showed that quality of manually extracted DNA was not enough for sequencing. Therefore, the quality of DNA was improved through additional purification steps. Briefly, host eukaryotic cells were removed by mechanical process and almost only bacterial DNA was successfully obtained by combination of manual extraction method and further purification processes. The established protocol was successfully introduced to extraction of metagenomic DNA from mussel and jellyfish microbiomes, indicating that it can be widely applied to various marine organisms.11Nsciescopuskc
Phylogeny of Desmidiales (Conjugatophyceae, Charophyta) in Korea based on multigene data analysis
No full text물먼지말목(Desmidiales, Conjugatophyceae, Charophyta)은 산성 습지, 호수, 늪, 이탄 습지 등의 환경에서 높은 종 다양성을 보이며 담수 생태계에서 흔히 볼 수 있는 분류군이다. 이들은 대칭적인 반세포로 구성된 독특한 형태적 특징을 가지며, 세포 형태와 크기의 변화 폭이 커서 형태학적 가변성이 높아 정확한 종 동정에 어려움이 있다. 현재까지 한국에서는 총 832종의 Desmidiales가 보고되었으나, 계통분류학적 연구는 일부 분류군에 국한되어 수행되었다. 본 연구에서는 국립낙동강생물자원관 담수생물자원은행(FBCC)의 배양주를 이용하여 Desmidiales의 종간 계통관계를 다유전자 분석을 기반으로 형태적 특성, 생태학적 정보 등을 통합하여 분석하였다. 총 352개의 유전자 서열을 새롭게 확보하였으며, 포함된 유전자는 accD(30개), atpA(42개), atpB(22개), ndhH(37개), petA(37개), psaA(32개), psbA(44개), psbC(1개), psbD(39개), rbcL(40개), rpl2(19개), rpoB(9개)이다. 12개 유전자 중에서 psbA는 가장 높은 보존부위 비율(83.9%)을 나타냈으며, petA는 가장 높은 변이부위 비율 (38.7%)을 보였다. 통합 계통 분석 결과, Desmidiales는 총 5개의 주요 분기군(clade)으로 분류되었다. Cosmarium Clade-1: Cosmarium punctulatum, Cosmarium sp. 1, Cosmarium Clade-2: C. blyttii, C. botrytis, C. costatum, C. ochthodes, C. pachyder- mum, C. subcostatum, C. subcrenatum, C. subprotumidum, C. trilobulatum, Cosmarium Clade-3: C. angulosum, C. for- mosulum, C. granatum, C. impressulum, C. norimbergense, C. regnellii, C. subtumidum, Cosmarium sp. 2, Staurastrum Clade-1: Staurastrum avicula var. lunatum, Staurastrum Clade-2: S. boreale, S. dispar, S. kouwetsii, S. margaritaceum, S. punctulatum. FBCC 배양주에서 확보된 새로운 유전자 서열 데이터는 정확한 종 동정과 담수 생태계 내 물먼지말 목의 분자생태학적 연구를 위한 기반 자료로 활용될 수 있다. 본 연구에서 제시한 계통학적 정보는 한국 내 물먼지말 목의 종 다양성에 대한 이해를 높이고, 해당 분류군에 대한 정교한 분류 체계 확립에 기여할 것으로 기대된다.
Desmidiales (Conjugatophyceae, Charophyta) are commonly found in freshwater ecosystems and exhibit high species diversity, particularly in acidic wetlands, lakes, swamps, and peat bogs. They possess a distinctive morphology characterized by symmetrical semicells, and their wide variation in cell shape and size presents challenges in species identification due to high morphological plasticity. Although 832 species of Desmidiales have been reported in Korea, phylogenetic studies have been limited to only a few taxonomic groups. This study focused on investigating species-level relationships among Desmidiales using strains from the Freshwater Bioresources Culture Collection (FBCC), integrating morphological characteristics, ecological data, and original species descriptions. A total of 352 new plastid gene sequences were generated for phylogenetic analyses, including accD (30), atpA (42), atpB (22), ndhH (37), petA (37), psaA (32), psbA (44), psbC (1), psbD (39), rbcL (40), rpl2 (19), and rpoB (9). Among the 12 plastid genes analyzed, psbA showed the highest proportion of conserved sites (83.9%), while petA exhibited the highest proportion of variable sites (38.7%). Based on the combined phylogenetic analysis, Desmidiales were grouped into five major clades: Cosmarium Clade-1: Cosmarium punctulatum, Cosmarium sp. 1, Cosmarium Clade-2: C. blyttii, C. botrytis, C. costatum, C. ochthodes, C. pachydermum, C. subcostatum, C. subcrenatum, C. subprotumidum, C. trilobulatum, Cosmarium Clade-3: C. angulosum, C. formosulum, C. granatum, C. impressulum, C. norimbergense, C. regnellii, C. subtumidum, Cosmarium sp. 2, Staurastrum Clade-1: Staurastrum avicula var. lunatum, Staurastrum Clade-2: S. boreale, S. dispar, S. kouwetsii, S. margaritaceum, S. punctulatum. The newly generated sequence data from FBCC strains will serve as a valuable resource for accurate species identification and for exploring the molecular ecology of Desmidiales in freshwater ecosystems. This phylogenetic framework improves our understanding of Desmidiales species diversity in Korea and aids in achieving a more comprehensive taxonomic resolution within this algal order.22Nkc
Effects of temperature changes on oxidative stress and antioxidant defense system in the Zhikong scallop Chlamys farreri
No full textTo understand the effects of temperature changes on the Zhikong scallop Chlamys farreri, we measured antioxidant-related enzymatic activities and oxidative-stress-related biomarkers, including the H2O2 and malondialdehyde (MDA) contents, in response to temperature changes (12 °C and 28 °C) compared with the control temperature of 20 °C, over 72 h. The scallops exposed to different temperature changes showed increased H2O2 levels with activation of antioxidant-related enzymes compared with the control during 12–24 h exposures. Following the temperature change, the MDA concentration was elevated for 24 h; however, after 24 h under low-temperature conditions, it decreased to levels similar to those seen in the control group, possibly owing to the defensive effects of antioxidant enzymes. The detoxification enzyme, glutathione S-transferase, showed a similar activity trend to those of other antioxidant enzymes for times up to 12 h; however, it did show inhibitory action after 24 h in response to the temperature changes relative to the control. These results indicate that C. farreri may experience greater oxidative stress in high-temperature environments. Overall, these findings indicate that temperature changes led to reactive oxygen species-mediated oxidative stress, resulting in cellular damage and activation of the antioxidant defense system in the Zhikong scallop.2
UNDERWATER COMMUNICATION INTERLOCKING APPARATUS AND UNDERWATER COMMUNICATION SYSTEM HAVING THE SAME
No full text본 발명은 수중통신연동장치 및 이를 포함하는 수중통신시스템에 관한 것이다. 종래 운용중인 수상함 내
지 잠수함에 구비된 능동소나에 본 발명이 제안하는 수중통신연동장치를 연동함에 따라, 표적탐지 외에도
수중통신기능을 추가적으로 수행할 수 있다. 이때, 통신내용은 능동소나 핑에 실려 수중으로 방사됨에 따
라 강한 신호로 원거리에 전달될 수 있으므로, 기존 수중통신기에 비해 수중통신능력이 향상될 수 있다.
또한, 디지털 신호처리 방식을 통하여 통신내용의 변조 및 복조를 수행함에 따라, 그 과정에서 통신내용
의 암호화 및 복호화가 가능하다. 즉, 보안 통신이 요구되는 군사적 목적 등으로 활용 가능한 수중통신 기
술을 제공할 수 있다. 또한, 새로운 수중통신기를 설계 및 제작하는 것이 아니라, 기존의 음향신호 송/수
신 기능을 구비한 능동소나를 이용하므로 기존 대비 진보된 수중통신기술을 구현하는데 비용이 절감될 수
있다
Side-Scan Sonar Image Synthesis Based on CycleGAN with 3D Models and Shadow Integration
No full textSide-scan sonar (SSS) is essential for acquiring high-resolution seafloor images over large areas, facilitating the identification of subsea objects. However, military security restrictions and the scarcity of subsea targets limit the availability of SSS data, posing challenges for Automatic Target Recognition (ATR) research. This paper presents an approach that uses Cycle-Consistent Generative Adversarial Networks (CycleGAN) to augment SSS images of key subsea objects, such as shipwrecks, aircraft, and drowning victims. The process begins by constructing 3D models to generate rendered images with realistic shadows from multiple angles. To enhance image quality, a shadow extractor and shadow region loss function are introduced to ensure consistent shadow representation. Additionally, a multi-resolution learning structure enables effective training, even with limited data availability. The experimental results show that the generated data improved object detection accuracy when they were used for training and demonstrated the ability to generate clear shadow and background regions with stability.11Nsciescopu
Combined stomach content and stable isotope analyses revealed variations in trophic ecology of pacific cod in the east sea
No full textThis study investigated changes in the dietary composition and trophic levels of Pacific cod (Gadus macrocephalus) using stomach content and stable isotope analyses. Pacific cod samples were collected seasonally from May 2018 to February 2022 using bottom gill nets at the northern (Ayajin) and southern (Hupo) sites of the East Sea along the Korean coast. The primary dietary components included teleosts, amphipods, carid shrimps, and cephalopods. Gravimetric dietary analysis revealed distinct latitudinal, seasonal, and size-related variations, with teleosts, cephalopods, carid shrimps, and euphausiids serving as the key prey items. During the cold season, teleosts constituted the major dietary components of the large-sized Pacific cod, whereas smaller individuals consumed more carid shrimps, amphipods, and euphausiids. In the warm season, large-sized individuals predominantly consumed cephalopods irrespective of location, whereas smaller individuals favored amphipods and euphausiids at Ayajin and carid shrimps at Hupo. Differences in stable isotope values (δ13C and δ15N) between Ayajin and Hupo, between size classes, indicated higher values in the Hupo and in large-sized individuals. Increased consumption of teleosts and cephalopods by larger Pacific cod led to enriched isotope values, whereas the contribution of carid shrimps elevated the trophic level at Hupo. This study provides comprehensive insights into the dietary variations and trophic levels of Pacific cod in response to changes in prey availability.11Ysciescopu
Application of the stability index in artificial sand nourishment projects in Cuba
No full textEffective sand nourishment for beach regeneration requires selecting sediments from a borrow zone compatible with the native materials, ensuring their stability and longevity. In Cuba, most of its beaches are predominantly covered by biogenic-marine sediments, and assessing the suitability of borrow sand presents unique challenges. This article compares two methods for assessing sand suitability in Cuba, where biogenic-marine sediments predominate: the Stability Index (Si) method and the traditional approach proposed in the Shore Protection Manual, herein referred to as the Overfill Factor (Ra) method. The Si method assesses compatibility by comparing grain-size distributions without assuming log-normality, while the latter uses the statistical parameter to estimate overfill requirements. The purpose of this study was then to provide a first assessment on this topic by evaluating a method that possibly allows for better adjustment than traditional methods, with the case studies on the beaches in Cuba specifically covered by biogenic-marine sediments. Using real-life case studies of artificial sand nourishment projects on beaches in this geographic region with varied sedimentary characteristics, we determined the performance of both Si and Ra methods in classifying borrow materials. The results of this initial approach suggest that the Si method offers greater flexibility when evaluating borrow zones, providing more accurate results and the possibility of utilizing areas that would have been discarded by conventional methods. The possibility of more efficient use of natural and economic resources is also becoming evident. Furthermore, it indicates that the application of Si is feasible in subsequent artificial sand replenishment projects in Cuba and on similar beaches with biogenic-marine sediments in the Caribbean region. This study represents the first application of a specific methodology to be applied for evaluation of the suitability of sand for Cuban projects, with the aim of its introduction as an additional tool for future studies.11Ysciescopu
Internet of Extreme Things Platform for Remote Antarctic Climate Monitoring
No full textIn this work, we introduce the implementation of a long-range wireless communication for remote Antarctic climate monitoring. Because each piece of equipment is installed in locations with limited access, our platform consists of an IoET device and a gateway for data collection, storage, and power control, and a large-capacity battery suitable for extreme environments. Each device can be powered on/off according to user requirements, enabling prolonged operation. The developed equipment is deployed at three control points: Jangbogo station, Mt. Melbourne, and Browning Pass. Each control point acts as a relay, transmitting data collected from nearby observation stations to the server at Jangbogo station. The communication distances between Browning Pass and Mt. Melbourne, and between Mt. Melbourne and Jangbogo station, are 50km and 35km, respectively. By establishing a reliable long-range communication network covering these distances, we demonstrate the feasibility of utilizing long-range wireless networks for IoET applications in Antarctica, thereby enhancing environmental monitoring and scientific research in challenging environments.1
