Search Results (205)

Deep-sea biological detection is a pivotal technology for the exploration and conservation of marine resources. Nonetheless, the inherent complexities of the deep-sea environment, the scarcity of available deep-sea organism samples, and the significant refraction and scattering effects of underwater light collectively impose formidable challenges on the current detection algorithms. To address these issues, we propose an advanced deep-sea biometric identification framework based on an enhanced YOLOv8n architecture, termed PSVG-YOLOv8n. Specifically, our model integrates a highly efficient Partial Spatial Attention module immediately preceding the SPPF layer in the backbone, thereby facilitating the refined, localized feature extraction of deep-sea organisms. In the neck network, a Slim-Neck module (GSconv + VoVGSCSP) is incorporated to reduce the parameter count and model size while simultaneously augmenting the detection performance. Moreover, the introduction of a squeeze–excitation residual module (C2f_SENetV2), which leverages a multi-branch fully connected layer, further bolsters the network’s global representational capacity. Finally, an improved detection head synergistically fuses all the modules, yielding substantial enhancements in the overall accuracy. Experiments conducted on a dataset of deep-sea images acquired by the Jiaolong manned submersible indicate that the proposed PSVG-YOLOv8n model achieved a precision of 79.9%, an mAP50 of 67.2%, and an mAP50-95 of 50.9%. These performance metrics represent improvements of 1.2%, 2.3%, and 1.1%, respectively, over the baseline YOLOv8n model. The observed enhancements underscore the effectiveness of the proposed modifications in addressing the challenges associated with deep-sea organism detection, thereby providing a robust framework for accurate deep-sea biological identification. Full article

The weathering of seafloor hydrothermal sulfides is facilitated by microbial activities, yet the specific mechanisms of different sulfide types are not well understood. Previous studies have primarily been carried out under laboratory conditions, making it difficult to accurately replicate the complex in situ conditions of deep-sea hydrothermal fields. Herein, we deployed two well-characterized pyrite (Py)-dominated and chalcopyrite (Ccp)-dominated sulfide slices, which were placed 300 m from an active venting site in the Wocan-1 hydrothermal field (Carlsberg Ridge, Northwest Indian Ocean) for an 18-month in situ incubation experiment. Microscopic observations and organic matter analyses were conducted on the recovered sulfide slices to investigate the microbial weathering features of different sulfide types. Our results demonstrated that the weathering of the Py-dominated sulfide sample was primarily mediated by extracellular polymeric substances (EPSs) through indirect interactions, whereas the Ccp-dominated sulfide sample exhibited both direct microbial dissolution, resulting in the formation of distinct dissolution pits, and indirect EPS-mediated interactions. Four distinct phases of microbe–sulfide interactions were identified: approach, adsorption, stable attachment, and extensive colonization. Furthermore, the weathering products and biomineralization structures differed significantly between the two sulfide types, reflecting their different microbial colonization processes. Our study confirms that microorganisms are crucial in seafloor sulfide weathering. These findings advance our understanding of microbial-driven processes in sulfide mineral transformations and their role in marine ecosystems. Our findings are also valuable for future research on biogeochemical cycles and for developing bioremediation strategies for deep-sea mining. Full article

Fruit vinegar is typically produced through a two-stage deep liquid fermentation involving alcohol fermentation (Saccharomyces cerevisiae) and acetic acid fermentation (Acetobacter pasteurianus). In order to enhance the flavor and texture of sea buckthorn fruit vinegar, Lactobacillus fermentum was introduced into the alcoholic fermentation stage. At the end of fermentation, the total acid and acetic acid of sea buckthorn (Hippophae rhamnoides L.) fruit vinegar were both enhanced compared with sea buckthorn vinegar brewed through the traditional liquid fermentation method, and in terms of the main active ingredients, the total flavonoid content was slightly enhanced. Non-targeted metabolomics (LC-MS) was used to characterize the characteristic metabolite profiles during the fermentation process. A total of 55 differential metabolites, including organic acids, flavonoids, and amino acids, were identified, and the contents of citric acid, malic acid, and manganic acid, which are the sources of the irritating taste of sea buckthorn berry vinegar, were significantly reduced. In addition, the co-fermentation of Lactobacillus fermentum promoted both glycolysis and the TCA cycle and also led to a significant up-regulation of aromatic metabolites, such as ethyl acetate, ethyl lactate, and ethyl caproate. These results will provide new information on the dynamics of the characterized metabolites during the fermentation of sea buckthorn fruit vinegar. Full article

The mechanical and hydrodynamic characteristics of single-piece nets are key to the design and optimization of offshore aquaculture net cages. A numerical approach for offshore submerged aquaculture net materials based on the Morison equations and finite element is proposed, simulating the hydrodynamic characteristics of single-piece nets under varying parameters such as wire diameter, mesh size, and flow velocity, and simulating the impact of marine organism attachment on nets by modifying the drag coefficient. The simulation results of nets made from materials such as Copper–Zinc Alloy (Cu-Zn), Zinc–Aluminum Alloy (Zn-Al), Semi-Rigid Polyethylene Terephthalate (PET), and Ultra-High Molecular Weight Polyethylene (UHMWPE) are compared, which provides a theoretical basis for optimizing design parameters and selecting materials for nets based on force conditions and hydrodynamic characteristics. The simulation results indicate that the current force on the net is positively correlated with flow velocity; the maximum displacement of the net is also positively correlated with the flow rate. Compared to other materials, the Cu-Zn net is subjected to the greatest water flow force, while the UHMWPE net experiences the greatest displacement; the larger the diameter of the netting twine, the greater the current force on the net; the mesh size is inversely related to the current force on the net. With increasing drag coefficient, both the maximum displacement of the net and the current force experiences increase, and UHMWPE material nets are more sensitive to increases in the drag coefficient, which indicates a greater impact from the attachment of marine organisms. The density and elastic modulus of the netting material affect the rate of increase in force on the net. The research results can provide a basis for further research on material selection and design of deep-sea aquaculture nets. Full article

The study of the influence of microorganisms on the formation of deep- and shallow-water ore deposits is a promising topic in environmental science. This problem, along with the role of organic matter in the growth of Fe-Mn nodules, remains understudied. This study focuses on the analysis of the composition and content of fatty acids in fast-growing Fe-Mn deposits and underlying sediments from various regions of the Kara Sea. Fatty acids serve as important biomarkers of diagenetic processes and reflect the different origins of organic matter. This work is based on the results of lipid extract analysis using GC–MS. Various sources of fatty acids were identified, including plankton, bacteria, terrestrial plants, and detrital material. It was found that FA content depends on the size of the nodules. Compared to underlying sediments, Fe-Mn nodules are enriched in FAs of bacterial and detrital origin, with SAFAs > MUFAs and a negligible content of PUFAs. Full article

Hadal zones account for the deepest 45% of oceanic depth range and play an important role in ocean biogeochemical cycles. As the least-explored aquatic habitat on earth, further investigation is still required to fully elucidate the microbial taxonomy, ecological significance, metabolic diversity, and adaptation in hadal environments. In this study, a novel strain Lsc_1132^T was isolated from sediment of the Mariana Trench at 10,954 m in depth. Strain Lsc_1132^T contains heterogenous 16S rRNA genes, exhibiting the highest sequence similarities to the type strains of Neobacillus drentensis LMG 21831^T, Neobacillus dielmonensis, Neobacillus drentensis NBRC 102427^T, Neobacillus rhizosphaerae, and Neobacillus soli NBRC 102451^T, with a range of 98.60–99.10% identity. The highest average nucleotide identity (ANI), the highest digital DNA-DNA hybridization (DDH) values, and the average amino acid identity (AAI) with Neobacillus sp. PS3-40 reached 73.5%, 21.4%, and 75.54%, respectively. The major cellular fatty acids of strain Lsc_1132^T included iso-C_15:0, Summed Feature 3 (C_16:1ω6c and/or C_16:1ω7c), iso-C_17:0, anteiso-C_15:0, and iso-C_17:1ω5c. The respiratory quinone of strains Lsc_1132^T was MK-7. The G + C content of the genomic DNA was 40.9%. Based on the GTDB taxonomy and phenotypic data, strain Lsc_1132^T could represent a novel species of a novel genus, proposed as Aliineobacillus hadale gen. nov. sp. nov. (type strain Lsc_1132^T = MCCC 1K09620^T). Metabolically, strain Lsc_1132^T demonstrates a robust carbohydrate metabolism with many strain-specific sugar transporters. It also has a remarkable capacity for metabolizing amino acids and carboxylic acids. Genomic analysis reveals a streamlined genome in the organism, characterized by a significant loss of orthologous genes, including those involved in cytochrome c synthesis, aromatic compound degradation, and polyhydroxybutyrate (PHB) synthesis, which suggests its adaptation to low oxygen levels and oligotrophic conditions through alternative metabolic pathways. In addition, the reduced number of paralogous genes in strain Lsc_1132^T, together with its high protein-coding gene density, may further contribute to streamlining its genome and enhancing its genomic efficiency. This research expands our knowledge of hadal microorganisms and their metabolic strategies for surviving in extreme deep-sea environments. Full article

Aquaculture is a globally widespread practice and the world’s fastest-growing food sector and requires technological advances to both increase productivity and minimize environmental impacts. Monitoring the sector is one of the priorities of state governments, international organizations, such as the Food and Agriculture Organization of the United States (FAO), and the European Commission. Data collection in aquaculture, particularly information on the location, number, and size of production facilities, is challenging due to the time required, the extent of the area to be monitored, the frequent changes in farming infrastructures and licenses, and the lack of automated tools. Such information is usually obtained through direct communications (e.g., phone calls and e-mails) with aquaculture producers and is rarely confirmed with on-site measurements. This study describes an innovative and automated method to obtain data on the number and placement of structures for marine and freshwater finfish farming through a YOLOv4 model trained on high-resolution images. High-resolution images were extracted from Google Maps to test their use with the YOLO model for the identification and geolocation of both land (raceways used in salmonids farming) and sea-based (floating sea cages used in seabream, seabass, and meagre farming) aquaculture systems in Italy. An overall accuracy of approximately 85% of correct object recognition of the target class was achieved. Model accuracy was tested with a dataset that includes images from Tuscany (Italy), where all these farm typologies are represented. The results demonstrate that the approach proposed can identify, characterize, and geolocate sea- and land-based aquaculture structures without performing any post-processing procedure, by directly applying customized deep learning and artificial intelligence algorithms. Full article

This study investigates the composition, abundance, and vertical export of polycyclic aromatic hydrocarbons (PAHs) across three deep basins of the northeastern Mediterranean Sea (NEMS) over one year. Sinking particles were collected using sediment traps, and PAH analysis was conducted via gas chromatography-mass spectrometry. PAH fluxes varied significantly, peaking in the north Aegean Sea due to mesotrophic conditions, nutrient-rich riverine and Black Sea water inflows, and maritime anthropogenic inputs. The fluxes were highest in winter and lowest in fall. In the Cretan Sea, petrogenic sources (~70%) dominated, driven by currents, with fluxes highest in spring and lowest in winter. The Ionian Sea exhibited lower fluxes, peaking in summer and decreasing in fall. Atmospheric deposition seems to be the main transport pathway of pyrolytic PAHs in this site, while its high-water column depth (4300 m) compared to the other sites presumably enables extended degradation of organic constituents during particle settling. The positive matrix factorization (PMF) and principal component analysis (PCA) results reveal complementary insights into PAH sources and transport mechanisms. PMF analysis identified combustion (61%) and petrogenic (22%) sources, while PCA highlighted biogenic fluxes (57.7%) and atmospheric deposition. Seasonal productivity, riverine inputs, and water circulation shaped PAH variability, linking combustion-related PAHs to atmospheric soot and petrogenic PAHs to organic-rich particles. Full article

The subsurface chlorophyll maximum depth (SCMD) is an indicator of the spatial activity of marine organisms and changes in the ecological environment. Ubiquitous mesoscale eddies are among the important factors regulating the Kuroshio–Oyashio confluence region. In this study, we use satellite altimeter observations and high-resolution reanalysis data to explore seasonal variations in the SCMD and its responses to different types of eddies based on methods of composite averaging and normalization. The results show that variations in the SCMD induced by the evolution of the eddies were prominent in the summer and autumn. The monopoles of the SCMD exhibited internally shallow and externally deep features in the cyclonic eddies (CEs), while the contrary trend was observed in the anticyclonic eddies (ACEs). The SCMD was positively correlated with the intensity of the eddies and sea surface temperature, and was negatively correlated with the depth of the mixed layer. These correlations were more pronounced in the CEs (summer) and ACEs (autumn). Both the CEs and ACEs prompted the westward transport of chlorophyll-a (Chl-A), where ACEs transported it over a longer distance than the CEs. Full article

At the end of the Middle Permian Guadeloupe series, the Chinese region recorded the only internationally recognized large igneous provincial eruption event, known as the Emeishan LIP. The Yangtze region of South China records a series of short and almost synchronous geological events that accompanied the development of bio-geological events such as large-scale magmatic intrusion, plate rupture, magnetic pole anomalies, and ecological collapse. These events ultimately triggered the extinction of living organisms. However, the current study leaves several questions unanswered. What was the sequence of geological events? Are the global records of these events synchronized? What is the causal relationship between these events? This study discusses the sedimentary responses to various geological events using biofossils, fluid inclusion, carbon isotopic analysis, and astrochronological analysis. The results reflect the following: (i) Mantle plumes: Mantle plumes act as pathways for heated fluids to ascend from the Earth’s interior. The mantle plume reached the Moho surface in the mid-Wordian and affected the magnetic field at the Earth’s surface; (ii) Magnetic pole anomalies: The anomaly of the Earth’s magnetic poles appeared in the mid-Wordian stage, causing the originally stable plates to begin to split. The sea level changes dramatically, and the ancient landform pattern changes dramatically; (iii) Plate rupture: The rifting of plates accelerated the activity of deep hydrothermal fluids; the hydrothermal fluid gradually infiltrated the paleo-ocean after the J. altudaensis zone; (iv) Emeishan LIP: The volcano erupted at 260 Ma, and eventually led to the mass extinction. We aim to identify the initial triggers of various geological events by analyzing the sedimentary record. Full article

Stylasterid corals are known to be fundamental habitat-formers in both deep and shallow waters. Their tridimensional structure enhances habitat complexity by creating refuges for a variety of organisms and by acting as basibionts for many other invertebrates, including sponges. Porifera represent crucial components of marine benthic assemblages and, in Antarctica, they often dominate benthic communities. Here, we explore the sponge community associated with thanatocoenosis, mostly composed of dead stylasterid skeletons, collected along the Western and Northern edges of the Ross Sea continental shelf. Overall, 37 sponge species were identified from 278 fragments of the stylasterid Inferiolabiata labiata, of which 7 are first records for the Ross Sea, 1 is first record for Antarctic waters and 2 are proposed as new species. Despite the high biodiversity recorded in this and previous studies on Antarctic deep-sea communities, we are still far from capturing the true richness of Antarctic benthic assemblages. Long-term research programs designed to improve the knowledge of the deep-sea fauna inhabiting Antarctic waters are needed to support successful management and conservation plans, especially in this area, considered one of the main marine diversity hotspots worldwide. Full article

The plumes generated during the collection of polymetallic nodules in the deep sea may have a significant impact on the marine ecosystem. Therefore, this article reviews the progress in deep-sea mining and monitoring technologies related to plumes. It is suggested that specific areas of environmental interest (APEIs) and positive altitude characteristic regions (such as seamounts and hills) in the process of polymetallic nodule collection can serve as refuges for benthic organisms and provide a biological basis for the recovery of biodiversity in mining areas. Water-supported vessels, pipeline lifting systems, and hydraulic collection methods are the least disruptive and most promising methods. By sorting out the deep-sea mining process, plumes can be roughly classified into seabed disturbance plumes and tailing plumes. The best way to address plume formation is at the source when developing environmentally friendly mining vehicles. The evaluation of plumes is crucial for the sustainable development of the environment and seabed resources. However, the mechanism is not clear at present. Therefore, laboratory simulation and in situ monitoring need to be coordinated, and attention should be paid to the impact on benthic marine organisms as much as possible during original operations. Plume research in the deep-sea mining process will also provide favorable support for the possible future development of seabed resources. Full article

Organisms occupy diverse ecological niches worldwide, each with characteristics finely evolved for their environments. Crustaceans residing in deep-sea hydrothermal vents, recognized as one of Earth’s extreme environments, may have adapted to withstand severe conditions, including elevated temperatures and pressure. This study compares the exoskeletons of two vent crustaceans (bythograeid crab Austinograea sp. and squat lobster Munidopsis lauensis) with four coastal species (Asian paddle crabs, blue crab, hermit crab, and mantis shrimp) to identify traits influenced by vent environments. The goal was to identify distinctive exoskeletal characteristics commonly observed in vent crustaceans, resulting from their exposure to severe abiotic factors, including elevated temperatures and pressures, found in vent environments. Results show that the exoskeletons of vent crustaceans demonstrated significantly enhanced thermal stability compared to coastal species. These vent crustaceans consistently featured exoskeletons characterized by a reduced proportion of volatile components, such as water, and an increased proportion of CaCO₃, compared with coastal crustaceans. Furthermore, vent crustaceans lacked carotenoid pigments that had low heat resistance. However, no apparent differences were observed in the mechanical properties. Our findings suggest that the similar composition of exoskeletons in vent crustaceans evolved convergently to withstand high temperatures. Full article

The deep sea, the largest biome on Earth, is the least explored and understood. This lack of knowledge hampers our ability to understand and protect this important environment. In this study, water and sediment samples were collected at different depths in the central Mediterranean (224–780 m), specifically, within the Dohrn Canyon and the Palinuro Seamount, to investigate the diversity of cephalopods and establish a baseline knowledge of their distribution in these sites to preserve their habitats and estimate the impacts of human-driven environmental changes. Key taxa identified included Heteroteuthis sp., Loligo sp., and Histioteuthis sp., which were the most abundant across all sampling stations. A low overlap in species detection was observed between water and sediment samples, confirming previous findings that the typology of environmental matrices used in eDNA metabarcoding has a significant impact on the organisms detected and, therefore, the integrated use of different matrices to better represent local biodiversity is recommended. Furthermore, this study highlights the limitations posed by gaps in reference databases, particularly for deep-sea organisms, and addresses these by emphasising the need for improved multi-marker approaches and expanded reference databases to enhance the accuracy of eDNA-based biodiversity assessment. Full article

Deep-sea mineral water (DSW) consists of different compositions and properties. The composition can be varied in different seas all around the world. However, previous studies have investigated that DSW is a potential candidate that can be used to prevent different inflammatory diseases. Even though inflammation is an important protective mechanism in an animal, excessive inflammation causes organ failure and ultimate death. Therefore, the present study was carried out to investigate the anti-inflammatory effect of DSW extracted from the South Korean Sea to unveil its potential as an anti-inflammatory drug. To perform this, first, we have compared the cytotoxic effect of DSW on RAW 264.7 murine macrophage cells with NaCl and normal-sea water (NSW). Results reveal that DSW enhances cell survival while other treatments negatively affect cell survival. Furthermore, we have investigated that DSW reduces the LPS-induced cell apoptosis compared to the NaCl- and NSW-treated cells. Moreover, DSW has the ability to suppress the pro-inflammatory cytokine transcription (TNF-α, IL-1β, and IL-6) and NO production upon LPS treatment. In-vivo survival assay in zebrafish larvae shows a more than 50% survival rate in 10, 20, 30, 40, or 50% concentrations of DSW-treated larvae compared to NaCl- or NSW-treated larvae. Further investigations unveiled that DSW can negatively regulate the neutrophil and macrophage recruitment to the inflammatory site, which was induced by fin-fold amputation in zebrafish larvae and pro-inflammatory cytokine (tnf-α, il-1β, and il-6) secretion. Taken together, the present study concluded that DSW may have the ability to act as an anti-inflammatory drug to suppress excessive inflammation and subsequent consequences. Full article