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Journal of Ocean University of China (English Edition)
Journal Prestige (SJR): 0.265  Citation Impact (citeScore): 1 Number of Followers: 1  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1993-5021 - ISSN (Online) 1672-5182 Published by Springer-Verlag  [2468 journals]
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- A New Method for In-Situ Measurement of Internal Solitary Waves Based on
the Stimulated Raman Scattering in Optical Fibers-
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Abstract: In-situ measurement of internal solitary waves (ISWs) is complicated in the ocean due to their randomness. At present, the ISWs are mainly detected by the chain structure of conductivity-temperature-depth systems (CTDs) or temperature sensors. The high cost limits the spatial resolution, which ultimately affects the measuring accuracy of the ISW amplitude. In this paper, we developed an experimental measurement system for detecting ISWs based on the stimulated Raman scattering in distributed optical fibers. This system has the advantages of high precision, low cost, and easy operation. The experimental results show that the system is consistent with CTDs in the measurement of vertical ocean temperature variation. The spatial resolution of the system can reach 1.0 m and the measuring accuracy of temperature is 0.2°C. We successfully detected 3 ISWs by the system in the South China Sea and two optical remote sensing images collected on May 18, 2021, the same day of two detected ISWs, verify the occurrence of the measured ISWs. We used the image pairs method to calculate the phase velocity of ISW and the result is 1.71 m s−1. By extracting the distances between wave packets, it can be found that the semi-diurnal tide generates the detected ISWs. The impact of the tidal current velocity on the ISW in amplitude is undeniable. Undoubtedly, the system has a great application prospect for detecting ISWs and other dynamic phenomena in the ocean.
PubDate: 2023-06-01
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- Synthesis and Excellent Antibacterial Activity of Ag2O-Loaded
Carboxymethyl Starch Nanocomposites-
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Abstract: Carboxymethyl starch/silver oxide nanocomposites (CMS-Ag2O NCs) were successfully fabricated by modifying carboxymethyl starch (CMS) with Ag2O obtained from an aqueous AgNO3 solution as silver source. Ag2O nanoparticles (NPs) formed on the surface of CMS by ion exchange. Based on SEM images, the diameters of Ag2O NPs were determined to be between 50 and 100 nm. From the XRD spectra of CMS-Ag2O NCs, the new diffraction peaks appeared at 33.88° and 38.08°, which were attributed to the Ag2O NPs. According to the XPS analysis, Ag 3d5/2 and Ag 3d3/2 peaks in CMS-Ag2O NCs were fitted into two main peaks centered at 367.6 eV and 373.6 eV, which were attributed to Ag+. The antibacterial efficiencies of CMS-Ag2O NCs against Escherichia coli, Staphylococcus aureus, Pseudoalteromonas tetraodonis, Micrococcus luteus, and Shewanella putrefaciens were determined to be 99.6%, 99.7%, 99.4%, 99.5%, and 99.6%, respectively. The antibacterial efficiencies of CMS-Ag2O NCs against the bacterial species were all greater than 99%. Therefore, these results indicated that CMS-Ag2O NCs was highly effective as a bactericidal agent against multiple bacterial species. CMS-Ag2O NCs can be further applied to antifouling coating.
PubDate: 2023-06-01
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- Wave Azimuth Cutoff Compensation Method and the Multisatellite Networking
Mode of SAR-
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Abstract: Synthetic aperture radars (SARs) encounter the azimuth cutoff problem when observing sea waves. Consequently, SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of waves with smaller wavelengths. To increase the accuracy of SAR wave observations, this paper investigates an azimuth cutoff compensation method based on the simulated multiview SAR wave synchronization data obtained by the collaborative observation via networked satellites. Based on the simulated data and the equivalent multiview measured data from Sentinel-1 virtual networking, the method is verified and the cutoff wavelengths decrease by 16.40% and 14.00%. The biases of the inversion significant wave height with true values decrease by 0.04m and 0.14m, and the biases of the mean wave period decrease by 0.17s and 0.22 s, respectively. These results demonstrate the effectiveness of the azimuth cutoff compensation method. Based on the azimuth cutoff compensation method, the multisatellite SAR networking mode for wave observations are discussed. The highest compensation effect is obtained when the combination of azimuth angle is (95°, 115°, 135°), the orbital intersection angle is (50°, 50°), and three or four satellites are used. The study of the multisatellite networking mode in this paper can provide valuable references for the compensation of azimuth cutoff and the observation of waves by a multisatellite network.
PubDate: 2023-06-01
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- Nutritional Metabolism of Antarctic Krill Product Protein in Rats
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Abstract: This work conducted a four-week metabolism test on rats to study the digestion and absorption characteristics of five protein-based krill products prepared from Antarctic krill as raw material. It aimed to provide theoretical support for the effective use of Antarctic krill protein and the development of novel protein resources. The results showed that the weight gain and true digestibility of the rats fed with krill meat, surimi and ordinary krill powder were significantly higher (P < 0.05) than those of the rats fed with traditional casein. Compared to casein, proteins from the five Antarctic krill products were found to significantly improve the net protein utilization (P < 0.05), and reduce the total cholesterol and triglycerides in the serum of rats (P < 0.05). In summary, the Antarctic krill protein-based products with high nutritional values can be used as a potential novel protein resource in the food industry.
PubDate: 2023-06-01
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- Responses of the Sea Surface Temperature and Suspended Matter
Concentration to ENSO Events in the Bohai Sea-
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Abstract: The sea surface temperature (SST) and sea surface suspended matter concentration data in the Bohai Sea were collected by multiple NOAA satellites from 1985 to 2018. The background calibration method was used to correct the systematic errors caused by the long-term observations through multiple NOAA satellites in this paper. Then, we studied the long-term variations of the sea surface temperature (SST) and sea surface suspended matter concentration (SSC) and their response to ENSO events in the Bohai Sea. Our results show that the SST and SSC of the Bohai Sea have been increasing since 1985, with an average rate of 0.04°C per year for SST, which is higher than the global average. The average increasing rate of SSC was 0.51 mg L−1 yr−1, which may be mainly due to the enhancement of winter monsoon in the Bohai. In winter, the SST and SSC of the Bohai Sea were higher in El Niño years than in La Niña years. In El Niño years, the ocean circulations were the main factor affecting the variation in SST. The robust circulation system caused by the strong winter monsoon enhances the water exchange between the cold water of the Bohai Sea and the warm water of the Yellow Sea, resulting in a higher SST in La Niña years. In summer, the SSTs of the Bohai Sea were lower in El Niño years than those in the La Niña years because of the decrease of the SST in the Western Pacific Ocean, the weakening of the subtropical high in the western Pacific, and its eastward shift caused by the El Niño events.
PubDate: 2023-06-01
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- Identification and Pathogen Stimulation Patterns of Neuronal Nitric Oxide
Synthase (nNOS) in Black Rockfish (Sebastes schlegelii)-
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Abstract: Neuronal nitric oxide synthase (nNOS) was the producer of nitric oxide (NO) which played important gas messenger molecules in biological process. It also can take effect as immune regulation molecule in organism. Black rockfish (Sebastes schlegelii) is an important economic fish which were widely farmed in East Asia countries. Meanwhile, the pathogenic bacteria such as the Edwardsiella tarda and Vibrio anguillarum in seawater always brought serious obstacles to their healthy growth. In order to explore the expression pattern of nNOS gene under the pathogen stimulation and predict its immune function, the nNOS gene in black rockfish named SsnNOS was identified. It was 3780 bp in length, located on chromosome 6, and contained 27 coding domain sequence (CDs). According to the phylogenetic analysis, the SsnNOS showed closest relative to the counterpart gene of swamp eel (Monopterus albus). Meanwhile, analysis of SsnNOS expression in various healthy tissues showed that SsnNOS expression level was highest in healthy brain tissues, followed by intestinal tissues. In addition, SsnNOS showed significant expression changes in response to stimulation by two pathogens. Particular in gill, the expression of SsnNOS after pathogenic stimulation increased significantly. The Elisa analysis showed the SsnNOS content in gills was much higher than that in other tissues at all time points. Moreover, the expression patterns of SsnNOS in brain, intestine and kidney after stimulation by pathogens showed a distinct expression pattern which first down-regulated and then up-regulated. Therefore, the SsnNOS may be an important signaling molecule for fish to respond rapidly in immune stimulation.
PubDate: 2023-06-01
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- An Innovative Approach to Predicting Scour Depth Around Foundations Under
Combined Waves and Currents in Large-Scale Tests Based on Small-Scale
Tests-
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Abstract: This study presents an innovative theoretical approach to predicting the scour depth around a foundation in large-scale model tests based on small-scale model tests under combined waves and currents. In the present approach, the hydrodynamic parameters were designed based on the Froude similitude criteria. To avoid the cohesive behavior, we scaled the sediment size based on the settling velocity similarity, i.e., the suspended load similarity. Then, a series of different scale model tests was conducted to obtain the scour depth around the pile in combined waves and currents. The fitting formula of scour depth from the small-scale model tests was used to predict the results of large-scale tests. The accuracy of the present approach was validated by comparing the prediction values with experimental data of large-scale tests. Moreover, the correctness and accuracy of the present approach for foundations with complex shapes, e.g., the tripod foundation, was further checked. The results indicated that the fitting line from small-scale model tests slightly overestimated the experimental data of large-scale model tests, and the errors can be accepted. In general, the present approach was applied to predict the maximum or equilibrium scour depth of the large-scale model tests around single piles and tripods.
PubDate: 2023-06-01
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- Analysis of Key Physiological Characteristics of Portunus trituberculatus
in Response to Short-Term Low Salinity Stress-
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Abstract: Salinity is a significant environmental factor that can affect the survival, metamorphosis, growth and feeding of Portunus trituberculatus. In order to analyze the key physiological characteristics of P. trituberculatus in response to short-term low salinity stress, the experiments of gradually decline and recovery as well as abrupt decline in salinity were carried out. The results showed that P. trituberculatus could survive in a certain low salinity range in the short term, and salinity 12 was the lowest tolerable salinity under the present experimental conditions. The change of the hemolymph osmotic pressure displayed significant positive correlations with water salinity, and the pressure was always higher than seawater osmotic pressure. Short-term low salinity stress changed the structure and morphology of gill tissue. The expansion of gill filament ends and epithelial cell shedding were conducive to osmotic adjustment. The activities of key ion transport enzymes such as Na+-K+-ATPase, carbonic anhydrase and V-ATPase also changed with the osmotic regulation, while Na+-K+-ATPase played a dominant role. In summary, as an osmotic adjustment species, P. trituberculatus rapidly adapt to the short-term low-salinity environment by osmotic adjustment in vivo, but salinity below salinity 12 is not conducive to its survival. Our result enriched the theoretical mechanism of osmotic regulation of P. trituberculatus, providing reference for the development of aquaculture technology of P. trituberculatus.
PubDate: 2023-06-01
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- Transcriptome Analysis Reveals the Regulation Role of miR-144-5p in
Intestinal Immunity of Japanese Flounder (Paralichthys olivaceus)-
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Abstract: MicroRNAs (miRNAs), 22-nucleotide-long micromanagers that guide the post-transcriptional regulation of a wide range of target genes, can theoretically be used as a diagnostic or therapeutic target for inflammatory reaction. In fish, miR-144-5p expression varies dramatically in response to the different bacterial infections and can regulate immunity-related genes to reduce the occurrence of inflammation. In this research, the regulation function of miR-144-5p to the intestinal innate immunity was udied in flounder Paralichthys olivaceus. The flounders were interfered by 2 µg g−1 miR-144-5p antagomir and their tissues (intestine, liver and spleen) were harvested from the fish at 12 h post-injection. More than 60 million high-quality reads were collected. At 24 hours after miR-144-5p or miR-NC interference, a total of 2704 and 1823 different-expresion genes (DEGs) were identified in comparison with control group, respectively. The DEGs were enriched in a variety of immunity-related signaling pathways, including NOD-like receptor, Wnt and Toll-like receptor signaling pathways, according to GO and KEGG analyses. A total of 503 highly interacting DEGs engaged in 33 immunity-related signaling pathways were discovered using KEGG analyses. Additionally, 5 hub genes were found by protein-protein interaction networks, which formed an intricate immune regulation network. Meanwhile, these hub genes were mostly involved in focal adhesion, Wnt signaling pathway, as well as the Intestinal Immune Network for IgT (IgA) Production Pathway. In conclusion, the loss of miR-144-5p can affect immunity-related genes and downstream signaling pathways. Our findings suggest that miR-144-5p is a modulator of gene networks and signaling pathways associated with intestinal innate immunity.
PubDate: 2023-06-01
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- Dynamic Response of Two-Degree-of-Freedom Riserless Drill String for
Vortex-Induced Vibration Suppression and Enhancement-
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Abstract: The mechanical behavior, dynamic evolution, and flow-field distribution of a two-degree-of-freedom riserless drill string were simulated numerically by using FLUENT fluid simulation software with the user-defined function embedded. The rotation angular velocities before and after the critical rotation angular velocity were used as independent variables, and the reduced velocity range was 3–14. Fluid-structure coupling was realized based on the dynamic overset grid and the SST k-ω turbulence model. Results reveal that the dynamic response of the riserless drill string was considerably affected by rotation and flow velocity, which are coupled with each other. The cross-flow average dimensionless displacement increased with the rotation angular velocity, and rotation considerably enhanced the in-line maximum average dimensionless displacement. However, the cross-flow amplitude caused by vortex-induced vibration was suppressed when the rotation angular velocity reached a certain value. The in-line and cross-flow frequencies were the same, thereby causing the trajectory to deviate from the standard ‘figure-eight’ shape and become a closed circle shape. The vortex did not fall behind the cylinder at low reduced velocity with high-rotation angular velocity, and the structure of the near-wake vortex remained U-shaped. The wake of the cylinder was deflected along the cross-flow direction, thereby leading to vibration asymmetry and resulting in increased vibration instability and disordered vibration trajectories, especially at high-rotation angular velocities.
PubDate: 2023-06-01
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- Research on the Marine Antifouling Ability and Mechanism of Acrylate
Copolymers and Marine Coatings Based on a Synergistic Effect-
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Abstract: Marine biofouling is an urgent global problem in the process of ocean exploitation and utilization. In our work, a series of zinc-based acrylate copolymers (ACZn-x) were designed and synthesized using benzoic acid, zinc oxide (ZnO) and a random quaternion copolymer consisting of ethyl acrylate (EA), butyl acrylate (BA), acrylic acid (AA) and methacrylic acid (MAA) by free radical polymerization and dehydration condensation. The ACZn-x with a zinc benzoate side chain is able to hydrolyze in natural seawater under static conditions, resulting in the formation of a smooth surface. We investigated and confirmed the antifouling (AF) behavior of ACZn-x in the laboratory and revealed that they have better antibacterial (86% for S. aureus and 72% for E. coli) and anti-algal (≥60.1% for N. closterium and ≥67.5% for P. subcordiformis) activities. We also assessed the marine AF properties of ACZn-x and corresponding coatings in Qingdao, China; the ACZn-x exhibited ideal AF properties with little silt and biological mucosa adhered to the ACZn-x surface after 6 months, and corresponding coatings exhibited little biofouling after 16 months in the ocean. Importantly, possible AF mechanisms were further proposed at the cellular level. These results could be helpful for the development and application of effective AF coatings.
PubDate: 2023-06-01
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- Performance Evaluation of Three Parameterizations on Internal Tidal Mixing
in the Northern Pacific-
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Abstract: The accurate assessment of the energy dissipation of internal tides (ITs) is of great importance because ITs contribute significantly to abyssal mixing. Thus, in this study, the IT-driven dissipation and diapycnal diffusion in the northern Pacific are estimated using parameterizations proposed by St. Laurent et al. (2002), Koch-Larrouy et al. (2007), and de Lavergne et al. (2020) (hereafter referred to as LSJ02, KL07, and dL20, respectively). The performances of the three parameterizations are evaluated by comparing the calculated results with fine structure observations. In particular, the dissipation estimated by LSJ02 parameterization shows a bottom-intensified characteristic, with the patterns showing good agreement with the observations near seamounts. Moreover, 43% of the results calculated using the LSJ02 parameterization have errors lower than one order of magnitude in the generation sites of ITs. Meanwhile, the strongest dissipation estimated by the KL07 parameterization shifts to the thermocline, with the results showing the highest level of consistency with observations in the generation sites. The proportion of results with errors lower than one order of magnitude is 80.7%. Furthermore, the results calculated by dL20 parameterization agree well with the observations in the upper and middle layers, with the parameterization showing an accurate estimation of the remote dissipation. The percentages of the errors lower than one order of magnitude between the dL20 parameterization and observations account for 77.1% and 88.7% in the generation sites and far-field regions, respectively.
PubDate: 2023-06-01
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- Impacts of Surface Exchange Coefficients on Simulations of Super Typhoon
Megi (2010) Using a Coupled Ocean-Atmosphere-Wave Model-
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Abstract: In this study, the effects of surface exchange coefficients on simulations of Super Typhoon Megi (2010) are investigated using a fully coupled ocean-atmosphere-wave model. Several experiments are conducted using different parameterization schemes for the drag (CD) and enthalpy exchange (CK) coefficients. For the selected case, considering only the leveling-off of CD at high wind speeds does not effectively improve the simulated typhoon track, intensity, or size. We found that increasing CK monotonically with wind speed (Komori et al., 2018) yields stronger winds and deeper pressures by enhancing latent and sensible heat fluxes, but typhoon intensity remains underestimated. We propose a new higher CK than that from Komori et al. (2018) based on the theory of Emanuel (1995). This approach produces a greater modeled typhoon intensity that is in good agreement with the best track data and effectively improves the track error for the simulation. Improved accuracy for modeled typhoon intensity is achieved with the new coefficient because CK/CD reaches the threshold of about 0.75 predicted by Emanuel (1995). The new proposed CK also results in a reasonably accurate modeled sea surface temperature. However, typhoon size and surface wave height are overestimated. This finding implies that more numerical tests for tropical cyclones of different nature (such as strong, weak, dissipating, rapidly intensifying, or weakening tropical cyclones) should be studied, and more physical processes should be explored in future coupled models.
PubDate: 2023-06-01
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- Seabed Physical Parameter Research Based on Active-Source OBS Data in the
Chukchi Sea Shelf of the Arctic-
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Abstract: The acquisition of seabed physical parameters is one of the focuses of marine acoustic researches. However, the active-source ocean bottom seismometer (OBS) detection method in the marine geophysical research is rarely used to acquire seabed physical parameters, and less work is performed in the Arctic. In this study, two active-source OBS data collected from the 9th and 11th Chinese National Arctic Research Expedition (CHINARE) are selected to obtain the physical parameters of seabed sediments. Two kinds of energy spark are used as the active sources, while the cost function inversion method is used based on the arrival time difference between the reflected and direct waves. The thickness and sound velocity of the sediment layers are obtained by inversion, and the empirical formula is used to calculate the physical parameters of the seabed sediment, which are compared with the measured results. The cost function inversion method based on the time difference of arrival of the reflected and direct waves is tested to be effective and feasible in the inversion of seabed parameters from active-source OBS data. The method is further applied to obtain the physical parameters of Chukchi seabed sediments, which provides the idea and reference for the application of marine geophysical active-source OBS detection technology in the inversion of polar seabed physical parameters.
PubDate: 2023-06-01
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- UGC-YOLO: Underwater Environment Object Detection Based on YOLO with a
Global Context Block-
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Abstract: With the continuous development and utilization of marine resources, the underwater target detection has gradually become a popular research topic in the field of underwater robot operations and target detection. However, it is difficult to combine the environmental semantic information and the semantic information of targets at different scales by detection algorithms due to the complex underwater environment. In this paper, a cascade model based on the UGC-YOLO network structure with high detection accuracy is proposed. The YOLOv3 convolutional neural network is employed as the baseline structure. By fusing the global semantic information between two residual stages in the parallel structure of the feature extraction network, the perception of underwater targets is improved and the detection rate of hard-to-detect underwater objects is raised. Furthermore, the deformable convolution is applied to capture longrange semantic dependencies and PPM pooling is introduced in the highest layer network for aggregating semantic information. Finally, a multi-scale weighted fusion approach is presented for learning semantic information at different scales. Experiments are conducted on an underwater test dataset and the results have demonstrated that our proposed algorithm could detect aquatic targets in complex degraded underwater images. Compared with the baseline network algorithm, the Common Objects in Context (COCO) evaluation metric has been improved by 4.34%.
PubDate: 2023-06-01
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- Immune Response of the Ridgetail White Prawn Exopalaemon carinicauda After
Exposure to the Dinoflagellate Prorocentrum minimum-
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Abstract: The dinoflagellate Prorocentrum minimum is known to affect the normal physiological function of Exopalaemon carinicauda by inducing oxidative stress, apoptosis, and cellular injury. To study the effects of P. minimum on the immune defense system of shrimp, E. carinicauda were exposed to 5 × 103 cells mL−1 and 5 × 104 cells mL−1 of P. minimum for 336h in treatment groups, while E. carinicauda cultured in filtered seawater was employed as control. The total hemocyte counts (THC), hemocyanin concentration (HEM), and the activity of alkaline phosphatase (AKP) in hemolymph serum, as well as expressions of six immunity-related genes in hemocytes, hepatopancreases and gills were determined. The exposure of P. minimum significantly reduced the THC, HEM concentration and AKP activity in hemolymph serum. Immunity-related genes expressed differently in hemocytes, hepatopancreases and gills. Compared with the control group, the expressions of Crustin and proPO in hemocytes were significantly up-regulated in the treatment groups, while the up-regulated expressions of LGBP, Lysozyme and Serpin were only found in the group exposed to 5× 104 cells mL−1 of P. minimum. In the gills of E. carinicauda exposed to P. minimum, the down-regulation of ALF, proPO and Serpin, up-regulation of LGBP and Lysozyme, as well as unaffected Crustin were observed. In hepatopancreases, the up-regulated expressions of LGBP, Crustin, Lysozyme, Serpin and proPO (only in 5 × 103 cells mL−1 of P. minimum group) were found in the treatment groups. After exposure to P. minimum for 336 h, shrimps were injected with Vibrio parahaemolyticus and WSSV. The results showed that the mortality rates of shrimp in the treatment groups were significantly increased with a dose-dependent effect, which suggests that exposure to P. minimum may reduce the immunity of E. carinicauda. The research indicates that hemocytes and hepatopancreases play important roles in protecting the shrimp immune response to harmful algae, while the protection effect of hemolymph serum and gills may be suppressed. Since the exposure to P. minimum depressed the immunity of E. carinicauda, further studies are needed to confirm whether the presence of the algae will affect the susceptibility of shrimp to pathogens.
PubDate: 2023-06-01
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- Oil Spill Risk Assessment of Offshore Pipeline in the Bohai Sea Under the
Perspective of Ecological Protection-
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Abstract: In recent decades, the exploration and development of marine oil and gas resources have increased significantly to meet the increasing energy demand of mankind. The Bohai Sea is a semi-closed continental sea that has a weak water exchange capacity and high ecological fragility. However, at present, more than 200 oil platforms have been built in the Bohai Sea, with more than 270 offshore oil pipelines having a length exceeding 1600 km. The oil spill pollution of offshore platforms has a great impact on the marine environment and ecosystems. Therefore, a comprehensive assessment of its risks is of great practical significance. This paper systematically constructs a comprehensive oil spill risk assessment model that combines the oil spill risk probability model and the ocean hydrodynamic model. This paper uses the Bohai Sea offshore pipeline as an example to assess its oil spill risk. The high-risk-value areas of the Bohai Sea offshore pipeline are mainly distributed at the bottom of Liaodong Bay, the bottom of Bohai Bay, near the Caofeidian area, and the northern part of the Yellow River Estuary.
PubDate: 2023-04-13
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- Seasonal Variability of Biofouling Community Structure in the Gulf of
Mannar, Southeast Coast of India: A Multivariate Approach-
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Abstract: In this research, an Underwater Biofouling Panel (UWBFP) system was erected for the qualitative and quantitative estimation of macro fouling organisms in the Gulf of Mannar. Forty-four biofoulers were identified from four types of selected test panels. Among these biofoulers, Amphibalanus amphitrite (Darwin, 1854) was the dominant one. The concrete panel encouraged the highest barnacle density compared to the other panels. Three series of test panels were used to assess the seasonal density of biofouling communities. The overall variation in barnacle count in the seaward and shoreward sides of all these three series were tested. They were found to be significantly different from each other. The greater variations in the barnacle density observed in this study in A-series of test panels could be due to the lack of or absence of other foulers to compete within the fortnight. The Shannon-Wiener species diversity index showed the highest diversity in wood substratum among the three series with greater accumulation of different types of fouling organisms. Multivariate analyses were also performed to understand the seasonal variation as well as the settlement pattern on the different directions of test panels based on validated data. PCA showed a strong variability (PC1 between 70.8 and 98.6% variance) between the directions of the panels in connection with barnacle density. The shade plot and CAP analysis segregated the short-term A-series test panels from the long-term (B- and C-series) test panels. Hence, the output was helpful in understanding the recruitment status of various faunal resources involved in the biofouling processes.
PubDate: 2023-04-04
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- Glutathione S-Transferase (GST) Identified from Giant Kelp Macrocystis
pyrifera Increases the Copper Tolerance of Synechococcus elongatus PCC
7942-
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Abstract: The glutathione S-transferases gene family plays an important regulatory role in growth and development, and responses to environmental change. In this study, six complete GST genes (MpGST1, MpGST2, MpGST3, MpGST4, MpGST5, and MpGST6) were cloned from the gametophytes of brown alga Macrocystis pyrifera. Subsequent bioinformatics analysis showed that these six genes encoded proteins with 202, 216, 288, 201, 205, and 201 aa, respectively. Moreover, MpGST3 differs from the other GST genes. Phylogenetic analysis suggested that MpGST3 belongs to the Ure2p type GST. Domain analysis suggested that the other GSTs from M. pyrifera belong to the soluble GST family and form an independent branch with the GSTs found in the other macroalgae, suggesting that a new GST type was formed during macroalgal evolution. GST genes were upregulated in M. pyrifera when 2.5 mg L−1 Cu ions were added to the medium. Six GST genes were integrated into the genome of Synechococcus elongatus PCC 7942, and their functions were verified by measuring light absorbance, photosynthetic pigment content, and photosynthetic parameters of the transformed strains under 0.3 mg L−1 Cu ion stress. The results showed much higher levels of various parameters in the transformed strains than in the wild strain. The transformed strains (with the MpGST genes) showed significantly enhanced resistance to Cu ion stress, while the wild strain almost died. The results of this study lay a theoretical foundation for further research on the Cu ion stress resistance function of GSTs in M. pyrifera.
PubDate: 2023-04-04
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- Identification and Characterization of Long Non-Coding RNAs Involved in
Sex-Related Gene Regulation in Kelp Saccharina japonica-
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Abstract: Long non-coding RNAs (lncRNAs) regulate a variety of biological processes, including sexual reproduction and differentiation. Saccharina japonica, a commercially important brown alga in China, shows remarkable sexual dimorphism in haploid gametophytes. The sex of Saccharina japonica gametophytes is determined by UV sexual system. However, no results have been reported on the lncRNAs involved in the sex-related gene regulation of S. japonica. This study identified a number of lncRNAs and assessed their expression levels in male and female gametophytes. Among them, a total of 405 lncRNAs and 211 mRNAs showed differential expressions. Furthermore, the functions of target genes of differentially expressed lncRNAs (DELs) differed from those of differentially expressed genes (DEGs), suggesting that lncRNA may interact with other functional proteins, in addition to DEGs, to involve sex regulation in S. japonica. There were 32 and 90 potential cis-regulatory and trans-regulatory interactions between DELs-DEGs, respectively. Five of these lncRNAs (LNC_002974, LNC_021059, LNC_038466, LNC_051584, and LNC_027400) interacted with putative male sex determination region (SDR) genes, suggesting that they act as regulators in gametophytes’ sex regulation potentially. Findings from this study contribute to our understanding of the roles of lncRNAs in sex differentiation and lay the foundation for functional studies of candidate lncRNAs in the future.
PubDate: 2023-04-04
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