Mesopelagic fish form an important link between zooplankton and higher trophic levels in Southern Ocean food webs, however their diets are poorly known. Most of the dietary information available ...comes from morphological analysis of stomach contents and to a lesser extent fatty acid and stable isotopes. DNA sequencing could substantially improve our knowledge of mesopelagic fish diets, but has not previously been applied. We used high-throughput DNA sequencing (HTS) of the 18S ribosomal DNA and mitochondrial cytochrome oxidase I (COI) to characterise stomach contents of four myctophid and one bathylagid species collected at the southern extension of the Kerguelen Plateau (southern Kerguelen Axis), one of the most productive regions in the Indian sector of the Southern Ocean. Diets of the four myctophid species were dominated by amphipods, euphausiids and copepods, whereas radiolarians and siphonophores contributed a much greater proportion of HTS reads for Bathylagus sp. Analysis of mitochondrial COI showed that all species preyed on Thysanoessa macrura, but Euphausia superba was only detected in the stomach contents of myctophids. Size-based shifts in diet were apparent, with larger individuals of both bathylagid and myctophid species more likely to consume euphausiids, but we found little evidence for regional differences in diet composition for each species over the survey area. The presence of DNA from coelenterates and other gelatinous prey in the stomach contents of all five species suggests the importance of these taxa in the diet of Southern Ocean mesopelagics has been underestimated to date. Our study demonstrates the use of DNA-based diet assessment to determine the role of mesopelagic fish and their trophic position in the Southern Ocean and inform the development of ecosystem models.
This study focused on the bloom-developing process of the giant jellyfish, Nemopilema nomurai, on phytoplankton and microzooplankton communities. Two repeated field observations on the jellyfish ...bloom were conducted in June 2012 and 2014 in the southern Yellow Sea where blooms of N. nomurai were frequently observed. We demonstrated that the bloom was made up of two stages, namely the developing stage and the mature stage. Total chlorophyll a increased and the concentrations of inorganic nutrients decreased during the developing stage, while both concentrations maintained stable and at low levels during the mature stage. Our analysis revealed that phosphate excreted by growing N. nomurai promoted the growth of phytoplankton at the developing stage. At the mature stage, size compositions of microzooplankton were altered and tended to be smaller via a top-down process, while phytoplankton compositions, affected mainly through a bottom-up process, shifted to be less diatoms and cryptophytes but more dinoflagellates.
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•Elucidation on effects of jellyfish blooming process on plankton communities.•Jellyfish blooms consist of two stages, the developing stage and the mature stage.•Growing jellyfish compensated for P deficiency and promoted phytoplankton growth.•Jellyfish blooms result in smaller sizes of microzooplankton via top-down control.•Jellyfish blooms lead to less diatoms and cryptophytes but more dinoflagellates.
•A Multi-Objective Jellyfish Search (MOJS) algorithm is developed to solve problems optimally with multiple objectives.•The proposed algorithm was tested on 20 mathematical benchmark functions, and ...compared with six well-known metaheuristic optimization algorithms.•Three structural design problems (25-bar tower, 160-bar tower and 942-bar tower) were efficiently solved by MOJS.•Mathematical tests and the structural design problems demonstrate the merits of MOJS in solving real problems with best Pareto-optimal fronts.
This study develops a Multi-Objective Jellyfish Search (MOJS) algorithm to solve engineering problems optimally with multiple objectives. Lévy flight, elite population, fixed-size archive, chaotic map, and the opposition-based jumping method are integrated into the MOJS to obtain the Pareto optimal solutions. These techniques are employed to define the motions of jellyfish in an ocean current or a swarm in multi-objective search spaces. The proposed algorithm is tested on 20 multi-objective mathematical benchmark problems, and compared with six well-known metaheuristic optimization algorithms (MOALO, MODA, MOEA/D, MOGWO, MOPSO, and NSGA-II). The results thus obtained indicate that the MOJS finds highly accurate approximations to Pareto-optimal fronts with a uniform distribution of solutions for the test functions. Three constrained structural problems (25-bar tower design, 160-bar tower design, and 942-bar tower design) of minimizing structural weight and maximum nodal deflection were solved using MOJS. The visual analytics demonstrates the merits of MOJS in solving real engineering problems with best Pareto-optimal fronts. Accordingly, the MOJS is an effective and efficient algorithm for solving multi-objective optimization problems.
Cnidarians play a crucial role in the marine ecosystem and are abundant in Moroccan waters, although their diversity remains poorly understood. This study aimed to assess the species richness of ...Cnidarians along the Moroccan Mediterranean coast through recent surveys and a literature review. A total of 104 Cnidarians species were identified in Moroccan waters. The recorded species were primarily distributed among different Cnidarian classes: 52 % were Anthozoans (55 species), 38 % were hydrozoans (40 species), 7 % were scyphozoans (8 species) and less than 1% are Cubozoans. Notably, four Scyphozoans (Rhizostoma luteum, Cotylorhiza tuberculata, Phyllorhiza punctata and Cyanea capillata) and one hydrozoan (Porpita porpita) were reported for the first time in the Moroccan Mediterranean. Additionally, four species were identified as alien to this region. Evaluation of the Anthozoans species recorded in Moroccan waters using the IUCN red list for the Mediterranean region, revealed that 9 out of the 55 species (16.36 %) were listed as threatened. These included 1 critically endangered species (1.81% of the total), 5 endangered species (9.09 %) and 3 vulnerable species (5.45 %). However, it is likely that the number of species on this list is underestimated due to the limited of studies conducted in the Mediterranean waters of Morocco. Therefore, further taxonomic and systematic studies of Cnidarians in Moroccan waters are crucial to provide a more comprehensive evaluation of the diversity of this group in this region.
•A novel algorithm is proposed to extract maximum power of photovoltaic system.•Discretization for proposed algorithm is designed to solve discrete problems.•An adaptive threshold is used to balance ...local exploration and global exploitation.•Consider various movement of clouds to evaluate proposed algorithm effectiveness.•Perform an electrical switching design to implement real-time embedded application.
This paper proposes an adaptive evolutionary jellyfish search algorithm (AEJSA) to optimally reconfigure photovoltaic (PV) array under partial shading condition (PSC) for real-time maximum power extraction. Jellyfish search algorithm (JSA) is selected owing to its effectiveness for real-time optimization. Besides, a series of discrete operations are performed on JSA to solve the discrete optimization problem of PV array reconfiguration. Due to the inherent drawback of JSA that it is easy to trap at the local optimal solution, an adaptive threshold for changing search mechanism is adopted to balance the local exploration and global exploitation. If the number of times that the value of objective function keeps unchanged exceeds this threshold, three operations (exchange, moving, and inver-over) will be implemented on the whole population for a wide global exploitation. In addition, to verify the feasibility of the hardware implementation of AEJSA, a hardware-in-the-loop test on a RTLAB platform is employed. Eleven meta-heuristic algorithms are applied and compared to AEJSA under objective PSC and subjective PSC to evaluate the optimized performance of AEJSA under various shadow conditions. The simulation results show that the mismatched power loss obtained by AEJSA is smallest, which reduced by 7.26% against gravitational search algorithm.
Modern agriculture has been fascinated by various advancements in agriculture and the processing of foods and supply management that provision farmers to improve production. The health of plants is ...essential to improve production and economic growth. Diseases in plants can affect production and create a rigorous impact on the quality and create a hazard to food safety. Hence, detecting and classifying plant leaf diseases is essential to prevent the disease spread across the plants in the agriculture field and to improve productivity. The researchers in existing frameworks utilized artificial intelligence and machine learning techniques to demonstrate noteworthy solutions. However, a few issues exist related to noises in the images, hyperparameter selection problems, and over-fitting problems that influence prediction accuracy. The proposed model jellyfish ResNet(JF-ResNet) works well to achieve a better accuracy level by incorporating jellyfish optimized ResNET for tomato plant leaf disease identification and classification. The performance metrics such as Accuracy, specificity, sensitivity, and F1-Score is used to evaluate the performance of the JF-ResNet model. The proposed model achieves 97.3% accuracy, 95.3% sensitivity, 96.1% specificity, 96.9% recall, 96.4% precision and 97.1% F1-Score.
Cannonball jellyfish, often commercialized as salted, dried jellyfish (SDJ), is an emerging fishery in the USA and a great source of collagen, which can be utilized for developing novel marine ...gelatin powders. The aim of this study was to determine the feasibility of producing gelatin powders with gelling properties from SDJ using a mild acid hydrolysis and freeze-drying procedure as well as to evaluate their physico-chemical properties. The findings revealed that the resultant gelatin powders had a moisture (g/100 g, dry basis, d.b.), crude protein (g/100 g, d.b.), ash content (g/100 g, d.b.) and water activity values of 4.82, 29.54, 56.61, and 0.09, respectively. Sodium, Al, and S were the main minerals detected in the jellyfish gelatin powders, which were agglomerated and had irregular morphologies with a mean particle size of 12.8 μm. Gels prepared with 5, 6.67, and 10% (w/v) jellyfish gelatin powder had Bloom values lower than 4.2 g; melting temperatures between 15.09 and 16.12 °C and their rheological behavior was effectively characterized by the Herschel-Bulkley flow model, which revealed non-Newtonian behavior and shear thinning phenomena. Higher apparent viscosities, yield stress, and consistency index values were observed in the gels prepared at higher concentrations of jellyfish gelatin powders and at lower evaluated temperatures. This study illustrates (for the first time) the feasibility of producing novel marine gelatin powders from SDJ, which have the potential to be used as gelling, thickening and/or binding agents in several food applications.
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•Salted, dry cannonball jellyfish (SDJ) were hydrolyzed with a citric acid solution.•Hydrolyzed jellyfish was freeze-dried then pulverized to produce gelatin powders.•Hydrolyzed SDJ (H-SDJ) powders showed gelling properties.•Rheological properties of H-SDJ gels were described by the Herschel-Bulkley model.•Gelatin gels made from H-SDJ exhibited melting temperatures between 15.1 and 16.1°C.
•Plotocnide borealis was the most abundant gelatinous species off the NE Greenland.•Distribution of gelatinous zooplankton was shaped by local bathymetry and hydrology.•Plotocnide borealis was an ...indicator of intermediate, colder shelf waters.•Aeginopsis laurentii distribution was mostly dependent on water salinity.•Aglantha digitale was associated with the warmer waters of Atlantic origin.
Gelatinous zooplankton are useful indicators of climate-driven shifts in the ocean; hence our study goal was to determine their diversity and distribution in the poorly investigated area of the Northeast Greenland shelf and adjacent waters. Zooplankton samples were collected vertically using a MultiNet in August and September 2017, at 9 stations along two transects: northern and southern. Eleven taxa were identified, of which Plotocnide borealis had the largest share within the assemblage in both transects. Gelatinous zooplankton biodiversity was the highest in the north. The local bathymetry and hydrology both shaped the distribution of the gelatinous zooplankton, leading to the emergence of three ecological groups: 1) taxa typically associated with, or found exclusively, in the intermediate, colder shelf waters (e.g. Plotocnide borealis); 2) organisms associated with higher temperatures and greater depths, mainly of the off-shelf waters (e.g. Aglantha digitale); 3) organisms whose distribution depended mainly on salinity and oxygen saturation (e.g. Aeginopsis laurentii). Additionally, A. digitale was associated with the presence of the warmer waters of Atlantic origin, the presence of which on both sides of the Fram Strait allowed to compare our findings with better studied gelatinous zooplankton from the West Spitsbergen Current, leading to the conclusion that the existent evidence of progressing Atlantification suggests that such impacts might also be expected off the Northeast Greenland coast.
Massive jellyfish outbreaks have put human lives and marine ecosystems in great danger. As a result, the jellyfish detection methods have drawn a lot of attention, following two directions optical ...and sonar imaging. This work focuses on using optical imagery and CNN-based deep-learning object detection models to detect jellyfish. While labeled data of jellyfish play an important part in training deep learning models, there are a few open and available labeled datasets. Hence, we create our dataset to train these models using our model-assisted labeling method with over 11 thousand images of underwater jellyfish and corresponding annotation files in PASCAL VOC format. Our model-assisted labeling method saves the work of classical manual labeling by 70 percent, which is developed into application with YOLOv5. However, the YOLOv5 baseline suffers from the trade-off between real-time performance and low accuracy. Hence, an improved YOLOv5-nano is introduced based on adding GAM and replacing conventional Conv with CoordCov modules into the backbone of the conventional structure. The experiment results show that our improved model increases the accuracy of the conventional one by 1.3% and outperforms others including RetinaNet, SSD, Faster R-CNN, YOLOv6, and YOLOv8 at 89.1% mAP@0.5. On generalization performance, we verify the effectiveness of our work by conducting a test set of 15 different types of jellyfish with various shapes, colors, resolutions, and backgrounds. To conclude, our work establishes a comprehensive system from labeling the data, improving object detectors, and developing a feasible real-time jellyfish detector.
Single-atom catalysts with extraordinary catalytic activity have been receiving great attention in tumor therapy. However, most single-atom catalysts lack self-propulsion properties, restricting them ...from actively approaching cancer cells or penetrating the interior of tumors. Herein, we design N-doped jellyfish-like mesoporous carbon nanomotors coordinated with single-atom copper (Cu-JMCNs). It is a combination of single-atom nanocatalytic medicine and nanomotor self-propulsion for cancer therapy. The Cu single atom can catalyze H2O2 into toxic hydroxyl radical (•OH) for chemodynamic therapy (CDT). Near-infrared light triggers Cu-JMCNs to achieve self-thermophoretic motion because of the jellyfish-like asymmetric structure and photothermal property of carbon, which significantly improves the cellular uptake and the penetration of three-dimensional tumors. In vivo experiments indicate that the combination of single-atom Cu for CDT and near-infrared light propulsion can achieve over 85% tumor inhibition rate. This work sheds light on the development of advanced nanomotors with single-atom catalysts for biomedical applications.
