The University of the Ryukyus (琉球大学, Ryūkyū Daigaku), abbreviated to Ryūdai (琉大), is a Japanese national university in Nishihara, Okinawa Prefecture, Japan. Established in 1950, it is the westernmost national university of Japan and the largest public university in Okinawa Prefecture. Located in the Senbaru neighborhood of the town of Nishihara, its campus borders both the village of Nakagusuku and the city of Ginowan.
With the rapid uptake of environmental DNA (eDNA) metabarcoding for a wide range of conservation and management uses, there is a growing need for guidance and best practices for species identification. A range of methodological and interpretive decisions influences taxa assignment. Here we provide a review and perspective of pitfalls and issues that can impact accurate taxonomic assignment across the full eDNA metabarcoding workflow: primer selection, lab handling, bioinformatics, taxonomic assignment, and communication of results. This paper addresses the complexities and challenges of the metabarcoding-based species identification process, offering recommendations for robust workflows and effective communication of findings. Accurate interpretation and communication of eDNA metabarcoding results requires an acknowledgment of methodological limitations such as incomplete reference databases, contamination risks, ambiguous sequences, and detection biases. Thus, we argue that transparency of methods and limitations, alongside proactive alignment of decisions with project objectives are critical for the successful application of eDNA metabarcoding in conservation and management decisions. We provide guidance for developing protocols that support species identification from eDNA metabarcoding sequences, and give recommendations on communication strategies for stakeholders and end users. To support these recommendations, we outline steps in the workflow that can impact species identification, with a discussion of the strengths and weaknesses at each stage. Ultimately, this guidance can improve the accuracy, reliability, and usability of eDNA and other metabarcoding and amplicon sequencing approaches to species identification while fostering trust and understanding among diverse end users.
Most corals possess tenuous morphologies prone to wounding from both abiotic and biotic factors. Under normal seawater temperatures, wound healing in corals is a vital biological process that takes time. In subtropical Okinawa, Japan, seawater temperature fluctuates seasonally from 20 to 30 °C. Climate change-driven ocean scenarios, such as extreme low temperatures, may intensify the stress caused by wider temperature oscillations, potentially impairing corals’ ability to recover from damage and increasing their susceptibility to infection, disease, and mortality. To ascertain the consequence of cold stress on coral wound healing, mechanically injured Acropora digitifera were exposed to different temperatures, including 21 °C (control), 18 °C (moderate stress) and 15 °C (severe stress). After 14 days, fragments in the control condition showed visible tissue and skeleton regeneration, confirmed by histological and scanning electron microscopy (SEM) analyses, respectively. This wound recovery was accompanied by increased light calcification and respiration rates, indicating that these processes likely play an important role in the recuperation of wounded corals. In contrast, severe cold stress caused mortality in both injured and uninjured individuals, thereby halting the healing process. Meanwhile, moderate cold stress, although not lethal, seemingly resulted in poor wound healing, as indicated by histological and SEM observations. Our findings add to the growing body of evidence demonstrating that cold stress may compromise coral wound recovery by potentially impacting physiological processes and increasing the risk of mortality, which could ultimately contribute to coral reef degradation.
Many animals and plants establish intimate symbiotic relationships with specific microorganisms acquired from the environment. Given the immense diversity of environmental microbiomes, selecting appropriate partners from such a vast microbial pool poses a critical challenge for host organisms. To meet this challenge, hosts have evolved sophisticated internal partner-choice mechanisms that ensure stable associations with beneficial microbes. However, because these symbionts primarily inhabit external environments, environmental conditions themselves are also expected to influence the establishment of symbiosis. Despite this expectation, the mechanistic role of external environmental filters in shaping the intended symbiosis remains largely unexplored. Focusing on stink bugs, which acquire their symbiotic bacteria from soil each generation, we investigated how soil properties influence the establishment of gut symbiosis in terrestrial insects. Microbiome analyses confirmed that Burkholderia sensu lato overwhelmingly dominates a specific gut organ in six stink bug species from the superfamilies Coreoidea and Lygaeoidea, including serious agricultural pests (relative abundance ranging from 74.5 to 100
Electrification is vital for economic growth, poverty reduction, and improved quality of life. Over 80% of Afghanistan's rural population lacks electricity. Despite increasing interest in decentralized energy systems, there remains a lack of site-specific studies that jointly assess the technical, economic, and policy feasibility of decentralized solar PV for rural electrification in Afghanistan. This study addresses that gap through a mixed-method case study of Syahgel, Ghazni, combining a household survey of 30 households, PVsyst-based system sizing, economic evaluation, and policy analysis. The study compares multi-tier Solar Home Systems (SHSs) with a community microgrid under local demand and affordability conditions. The results show that SHSs, with entry-level costs starting from USD 95, are more suitable for small, dispersed settlements, while microgrids remain relevant for larger or more concentrated communities. Financing mechanisms, including subsidies and interest-free loans, can improve affordability by up to 75%, while electrification can reduce annual fuelwood expenditure by approximately USD 51.5 per household and generate broader health, educational, and livelihood benefits. The findings highlight the need for integrated policy reform, targeted financial support, and context-sensitive system design to support sustainable and inclusive rural electrification in Afghanistan.
Understanding the variability of Total Suspended Sediment (TSS) is essential for managing sediment-related pollution in estuarine and coastal environments. This study aimed to analyze the spatial and temporal variability of TSS along the Banda Aceh coast, Indonesia, and its extended impacts on the surrounding environment using an integrated approach that combines satellite remote sensing, hydrodynamic modeling, and multivariate statistical analysis. Satellite-derived TSS concentrations were estimated from Sentinel 2A imagery using empirical algorithms, with the green/blue band ratio (B3/B2) performing best (R2 = 0.47, RMSE = 21.73 mg/L) against in-situ observations. Hydrodynamic simulations conducted using MIKE 21 revealed marked spatial and temporal variability in TSS distribution driven by tidal conditions and estuarine morphology. During spring tides, stronger currents (up to 0.45 m/s) facilitated widespread TSS dispersal offshore, with concentrations exceeding 250 mg/L in Ulee Lheue and Alue Naga Estuary. In contrast, neap tides resulted in slower current speeds (< 0.20 m/s) and higher TSS retention near the river mouths. The Krueng Aceh Estuary exhibited more stable and lower TSS concentrations (< 181 mg/L) because of its open configuration and reduced sediment trapping. Principal Component Analysis showed that the TSS was positively correlated with turbidity and chlorophyll-a, underscoring its role in controlling water clarity and nutrient dynamics. These findings demonstrate the dominant influence of tidal dynamics, anthropogenic contributions, and riverine discharge on the coastal water quality. The combined remote sensing–modeling framework offers a scalable approach for sediment monitoring and management in other vulnerable, urbanizing coastal systems.
