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Volume 43 ， Issue 1 ， 2025
- Abstract：Global warming has been reported to enhance thermal stratification and decrease the mix-layer depth (MLD) in waters due to higher surface water temperatures, especially in summer. Previous studies were conducted for individual cases or specific periods. At present, there is a lack of global assessments on the influence of climate warming in different seasons on thermal stratification. The ECMWF Reanalysis v5 (ERA5) dataset was used to estimate the variability of water body mixing and its drivers in different seasons and regions. Results indicate that global warming could enhance thermal stratification and decrease the MLD globally in summer. Wind speed was the primary driver of MLD changes, followed by temperature. However, ice melt due to global warming enhanced the mixing in ice-covered waters in the Northern Hemisphere, and early ice melt led to early mixing. Ice depth was the primary driver of MLD changes in the Northern Hemisphere due to delayed ice formation and earlier melting, while wind speed was the primary driver in other regions or during ice-free seasons. The enhanced mixing due to earlier ice melt out in late winter and early spring could promote water circulation and nutrient turnover, and replenish dissolved oxygen in deep water, thereby promoting the maximum biomass of cyanobacteria and advance harmful algal blooms.Keywords：global warming;mix-layer depth (MLD);thermal stratification;ice depth;ECMWF Reanalysis v5 (ERA5) dataset19|14|0Updated：2025-02-19
- Abstract：Obtaining accurate ship positions and headings in remote sensing images plays a crucial role in various applications. However, current deep learning-based methods primarily focus on ship position detection, while the detection of ship wakes relies on traditional non-deep learning approaches, which often underperform in complex marine environments. We proposed a novel, simple, and efficient method called Point-Vector Net. The proposed method leverages convolutional neural networks (CNN) for feature extraction and subsequently integrates multi-scale features to generate high-resolution feature maps. In the final stage, ship positions and headings are represented using a combination of points and vectors. Comparative experiments with results from automatic identification system (AIS) reports demonstrate that our method achieved impressive performance in two-class ship target detection, with an average precision of 96.4%, recall rate of 94.3%, and an F1 score of 95.2%. Notably, the average heading error was 3.3°. The proposed model achieved a practical inference speed (FPS>30), and the average processing time for inferring a large-scale Sentinel-2 remote sensing image was 11.4 s.Keywords：deep learning;ship detection;heading;remote sensing;Sentinel-211|13|0Updated：2025-02-19
Physics
- Abstract：Marine carbonates, the major carrier of carbon upon the upper crust, can be subducted into the Earth’s interior along with oceanic crust, and then returned to the surface through magmatism, which constitute the deep carbon cycle. This process plays an important role in modulating the CO2 concentrations in the atmosphere over geologic time, and thus the forming of the habitable earth. Therefore, identifying recycled marine carbonates in the mantle is critical to well understand the global deep carbon cycle. Calcium is one of the major constituent cations in marine carbonates and its isotopes may be a potential tracer for recycled marine carbonates in the mantle. To further evaluate the capability and challenges of Ca isotopes as such a geochemical tracer, we reviewed the Ca isotopic compositions in important reservoirs and the behavior of Ca isotopes during high-temperature geological processes that are related to the deep carbon cycle, including plate subduction, mantle metasomatism, mantle partial melting, magma differentiation, etc. Available studies show that carbonate-rich marine sediments have significantly lower δ44/40Ca than the Earth mantle, and metasomatism by such recycled materials can cause lighter Ca isotopic compositions in deep mantle-derived rocks than those of the depleted mantle and mid-ocean ridge basalts. However, the Ca isotopic fractionation during partial melting of mantle peridotites is small (~0.10‰) and the Ca isotopic fractionation during plate subduction and intermediate-mafic magma evolution is indistinguishable. These investigations suggest that Ca isotopes have great advances in tracing such recycled materials in the mantle. However, other processes (such as the influence by partial melts of eclogites) may induce similar effects on mantle-derived rocks as subducted marine carbonates but still remains debated, and thus further investigations are strongly needed in the future.Keywords：Ca isotope;marine carbonate;mantle metasomatism;partial melting;fractional crystallization14|14|0Updated：2025-02-19
- Abstract：Palaeowind regime is an important component for reconstructing palaeoclimate and understanding ancient global circulation. We applied the beach-ridge thickness technique (BTT) and the longshore-bar thickness technique (LTT) to reconstruct the Early Cretaceous palaeowind velocities based on depositional records of Tanan Depression in Northeast Asia. The thickness of beach ridges and nearshore bars is the most important parameter for applying the BTT and the LTT methods. We identified 22 beach ridges and 23 nearshore bars based on drilling cores and wireline-log data in the Tanan Depression. Palaeowind velocities calculated by using the LTT method ranged from 10.84 to 13.66 m/s, showing a narrower range than those calculated by using the BTT method (7.58–15.93 m/s). We further analyzed the underlying factors causing the difference between the results derived from these two methods based on the sedimentary process of the beach ridge and the nearshore bar. The reconstructed wind regime was assumed to be the summer monsoon originating from the Mongol-Okhotsk Ocean before it had been completely enclosed, which provides valuable insight into the understanding of the atmospheric circulation in Northeast Asia during the Early Cretaceous.Keywords：palaeowind;beach ridge;nearshore bar;Early Cretaceous;East Asia summer monsoon9|11|0Updated：2025-02-19
- Abstract：The Ninety-East Ridge (NER) is located in the semioceanic to oceanic region of the southern Bengal Fan in the Northeast Indian Ocean. The sedimentary environment, ocean currents, and scientific issues related to climate change have always been the focus of scientists. To well understand the sedimentary environment of the sea area, we studied the modern sedimentary environment of the NER by analyzing the redox-sensitive trace elements (RSEs) and biomarkers in the surface sediments of the northern region and both sides of the NER and the mechanism of their formation. The ratios of Mo/U (average 2.22), (Cu+Mo)/Zn (average 1.51), and the results of δCe<1 of the sediment samples, all indicate the reduction of the sedimentary environment. In addition, the ratio of pristane (Pr) to phytane (Ph), C30 diahopane to C30 hopane, and diasterane to sterane were low in all samples, on average of 1.03, 0.9, and 0.33, respectively. The analysis of RSE and biomarker data revealed that the sedimentary environment on seabed of the NER is generally a rare low-oxygen reduction environment. Through the analysis of sediment characteristics, material sources, and ocean currents, we preliminarily constructed a genetic model for the low-oxygen reducing environment of surface sediments in the NER. We believe that the low-oxygen reduction environment of surface sediment in the NER could be influenced by multiple factors, such as terrestrial input of materials, productivity at sea surface, and sediment particle size.Keywords：Ninety-East Ridge (NER);surface sediment;sedimentary environment;redox-sensitive trace elements (RSEs);biomarker17|16|0Updated：2025-02-19
Geology
- Abstract：High-dimensional data (a dataset with many features) were collected from 64 sampling sites to analyze the water quality in estuaries along the coast of the Bohai Sea, North China. The twenty-five water quality parameters analyzed were collected monthly from January 2021 to December 2021. Multivariate statistical techniques, such as the absolute principal component score-multiple linear regression model (APCS-MLR), correlation analysis, and analysis of variance were used to identify and quantify the potential sources or factors affecting water quality and to analyze the spatial-temporal variation in water quality. The water quality indices (WQIs), ranging from 67.96 to 70.67, showed that the water quality was at an intermediate level in the estuaries during both the flood and nonflood seasons. The concentrations of total phosphorus (TP), ammonia N (AN), and organic pollutants were greater in the Haihe River Basin than in the Liaohe River and Huanghe-Huaihe River Basins. The concentration of total nitrogen (TN) in the Haihe River Basin was lower than that in the Liaohe River and Huanghe-Huaihe River Basins. Heavy metal concentrations in the Liaohe River Basin were greater than those in the Haihe River and Huanghe-Huaihe River Basins. The annual mean concentrations of AN in the estuaries of the Haihe, Liaohe, and Huanghe (Yellow) rivers exhibited significant decreasing trends from 2013 to 2022, but no significant decreasing trends were found for permanganate index (CODMn) or the TP. The concentrations of TN and AN were lower in the flood season than in the nonflood season, and the TP concentration was greater in the flood season than in the nonflood season. However, the concentrations of organic pollutants did not exhibit significant differences. Domestic sewage and industrial wastewater, substance exchange between air and water, nonpoint sources from rural and urban areas, and aquaculture wastewater were the major sources or factors responsible for water pollution in the estuaries.Keywords：water quality;spatial-temporal variation;source apportionment;absolute principal component score-multiple linear regression;estuary;Bohai Sea5|15|0Updated：2025-02-19
- Abstract：Saltmarsh is one of the blue carbon ecosystems for the highest carbon burial efficiency. However, the buried carbon in saltmarsh may still be exported to coastal water through porewater exchange, a process that has often been overlooked in previous studies. A typical tidal creek of the Dongtan saltmarsh wetland in Chongming Island, Shanghai, China, was studied. The 224Ra and 223Ra activities were measured and the hydrological parameters such as water flow were determined, from which the porewater exchange rate in the tidal creek was estimated to be 1.78±1.73 cm/d. Meanwhile, the carbon concentrations in porewater were determined, based on which the fluxes of dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), CH4, and CO2 exported from porewater exchange were derived to be 60±17, 6.6±4.0, 0.082±0.079, and 16±11 mmol/(m2·d), respectively. In addition, analysis on different species of carbon in the creek water showed that, the fluxes of DIC, DOC, CH4, and CO2 exported laterally from tidal creek to coastal sea were 58±14, 7.6±2.3, 0.001 1±0.000 63, and 1.5±0.68 mmol/(m2·d), respectively, indicating that the porewater exchange-derived carbon fluxes accounted for a large portion of the lateral carbon outwelling, and even much higher than those in CH4 and CO2 fluxes. Furthermore, the carbon exported from porewater exchange accounted for 50% of the carbon burial in the tidal creek system, of which DIC accounted for 73% of the total carbon flux transported by porewater exchange. Therefore, this study indicated that the porewater exchange-derived carbon fluxes to the tidal creek water may cause an overestimation in the carbon sequestration capacity of saltmarsh wetlands, and revealed the importance of porewater exchange for the carbon cycle of tidal creek system of saltmarsh wetlands.Keywords：coastal saltmarsh;porewater exchange;radium;blue carbon;tidal creek;carbon lateral outwelling11|14|0Updated：2025-02-19
Chemistry
- Abstract：Pollution from heavy metals (HMs) (Cd, As, Cr, and Ni, etc.) has become a serious environmental issue in urban wetland ecosystems with more and more attention. Previous studies conducted in agricultural soils, rivers, and lakes demonstrated that microbial communities exhibit a response to HM pollution. Yet, little is known about the response of microbial communities to HM pollution in urban wetland ecosystems. We examined how heavy metals affect the stability of the microbial networks in the sediments of Sanyang wetland, Wenzhou, China. Key environmental parameters, including HMs, TC (total carbon), TN (total nitrogen), TP (total phosphorus), S, and pH, varied profoundly between moderately and heavily polluted areas in shaping microbial communities. Specifically, the microbial community composition in moderately polluted sites correlated significantly (P<0.05) with Ni, Cu, Cd and TP, whereas in heavily polluted sites, they correlated significantly with Cd, TN, TP, and S. Results show that the heavily polluted sites demonstrated more intricate and more stable microbial networks than those of the moderately polluted area. The heavily polluted sites exhibited higher values for various network parameters including total nodes, total links, average degree, average clustering coefficient, connectance, relative modularity, robustness, and cohesion. Moreover, the structural equation modeling analysis demonstrated a positive correlation between the stability of microbial networks and Cd, TN, TP, and S in heavily polluted sites. Conversely, in moderately polluted sites, the correlation was positively linked to Cd, Ni, and sediment pH. It implies that Cd could potentially play a crucial role in affecting the stability of microbial networks. This study shall enhance our comprehension of microbial co-occurrence patterns in urban wetland ecosystems and offer insights into the ways in which microbial communities respond to environmental factors in varying levels of HM pollution.Keywords：heavy metal (HM);urban wetland;microbial networks;network stability10|11|0Updated：2025-02-19
- Abstract：Understanding the response of the phytoplankton community to climate change is essential for reservoir management. We analyzed a long-term data series (2009–2020) on the phytoplankton community in a large mesotrophic reservoir in the wet season to investigate the impacts of temperature and precipitation increases caused by climate change on the functioning and trait composition of the phytoplankton community. Over the last twelve years, the 3-month accumulative precipitation increased from 291.03 mm to 590.91 mm, and the surface water temperature increased from 25.06 ℃ to 26.49 ℃ in wet season, respectively. These changes caused a higher water level, stronger thermal stratification and lower nitrogen concentration in Daxi Reservoir. The dynamic equilibrium model indicated that the increased precipitation and water temperature-related environmental changes would result in a more diverse and productive phytoplankton community. The effects of increasing water temperature and precipitation on the niche complementarity and selection effects within the phytoplankton community were analyzed using structural equation model by means of the functional divergence index and functional evenness index, respectively, elucidating the reasons for the increase in cyanobacteria in the absence of a significant increase in nutrient levels. Based on these results, it is advisable that more stringent phosphorus control standards might be conducted to reduce the risks of cyanobacteria proliferation in the context of global warming.Keywords：global warming;climate change;reservoir;trait-based phytoplankton functional group;cyanobacteria4|9|0Updated：2025-02-19
- Abstract：The functional diversity index of a phytoplankton body has gradually become a new mean of measuring and research. To explore the response of phytoplankton taxonomy and the functional diversity index to interannual environmental changes, a survey on the structure of the phytoplankton community and water physicochemical characteristics of the water was carried out at 28 sampling points in the Harbin section of the Songhua River for three consecutive years in every May from 2021 to 2023. The taxonomy diversity index and the functional diversity index were calculated. Firstly, The relationship between the structure of the characteristics of the community and environmental factors was explored; secondly, we reveal the responses of taxonomic and functional diversity indices to different habitats between years; finally, we explore the main environmental factors that control the taxonomic and functional diversity indices of phytoplankton. Results show that, initially, environmental factors in water changes caused by different water levels between years affected the composition of phytoplankton communities. Subsequently, by comparing the taxonomic diversity index and the functional diversity index on a time scale, we found that the taxonomic diversity index was more responsive to environmental changes. Ultimately, the main environmental factors on the phytoplankton taxonomic diversity index were dissolved oxygen, Taxonomic diversity index, and specific conductivity, and the main environmental factors that affected the functional diversity index were dissolved oxygen, turbidity, and water temperature. This study reveals the important role of the taxonomic diversity index in river water quality evaluation, obtained new information on the relative precision of the taxonomic diversity index and the functional diversity index in the evaluation of ecological health of the water, and provided a reliable tool for monitoring river water quality based on aquatic organisms.Keywords：Songhua River Basin;phytoplankton;functional diversity;biodiversity index;watershed ecology10|11|0Updated：2025-02-19
- Abstract：Suitable temperature and light intensity play important roles in the formation of harmful algae blooms (HABs), which can pose serious threats to aquatic ecosystems and human health. In this study, we measured the growth, physiological function, and paralytic shellfish toxins (PSTs) production of Alexandrium pacificum (CCMA-272), a strain isolated from East China Sea, at different temperatures (15, 20, and 25 °C) and light intensities (30, 60, and 90 μmol photons/(m2·s)). Results indicate that temperature and light intensity significantly affected the growth, physiology, and toxigenic potentials of A. pacificum. The optimal conditions for the growth of A. pacificum were observed at 20 °C under 60 μmol photons/(m2·s). Regarding the production of PSTs, this strain of A. pacificum produced 12 PSTs, including carbamate toxins: saxitoxin (STX), neosaxitoxin (NEO), and gonyautoxin 1–4 (GTX1, GTX2, GTX3, GTX4); dicarbamoyl toxins: dicarbamoylsaxitoxin (dcSTX), dicarbamoylgonyautoxin 2, 3 (dcGTX2, dcGTX3); and N-sulfocarbamoyl toxins: N-sulfocarbamoylgonyautoxin 1, 2 (C1, C2), and gonyautoxin 5 (GTX5). Among all the PSTs, C2 was the most abundant. Low temperature (15 °C) and high light intensity (90 μmol photons/(m2·s)) were beneficial for the production of PSTs in A. pacificum. When cultured at 20 and 25 °C, A. pacificum generated comparable total quantities of PSTs, yet the toxicity levels were lower at 25 °C. Intra-cellular PSTs contents were greater than extra-cellular PSTs contents, except those under the condition of 25 °C with 30 μmol photons/(m2·s). However, as the increase of temperature, A. pacificum released more amounts of analogues with higher toxicity levels (e.g., STX and dcGTX2) into the environment than intracellularly. These findings emphasize the significant sensitivity of A. pacificum to temperature and light intensity, highlighting the importance of evaluating both intra-cellular and extra-cellular PSTs for assessing its toxicity and aiding in the prediction and management of HABs.Keywords：temperature;light intensity;Alexandrium pacificum;paralytic shellfish toxin;harmful algal bloom3|7|0Updated：2025-02-19
- Abstract：The northern East China Sea and Yellow Sea are highly dynamic marginal seas, serving as important fishing grounds and primary areas for aquaculture. The zooplankton community structure, including abundance, biovolume, and normalized biovolume size spectra (NBSS) within this ecosystem in summers 2021 and 2022 was assessed through ZooScan digital imaging system. The abundances of zooplankton in summers 2021 and 2022 were 3 364.22±2 190.53 and 4 435.52±2 520.06 inds./m3, respectively, whereas the corresponding biovolumes were 649.10±519.63 and 1 064.86±1 254.87 mm3/m3, respectively. Small copepods as the dominant zooplankton functional group in terms of abundance in both years, while chaetognath and medusae were the dominant groups in terms of biovolume. The dominance of medusae and chaetognath in terms of biovolume, along with the flatter slopes of NBSS compared to a stable community, indicated that more energy accumulated in gelatinous organisms within the study area. There were significant positive relationships between temperature and tunicates or medusae, with a significantly higher population size observed in summer 2022 than in 2021. The lower abundance and biovolume of zooplankton, mainly of small copepods, in summer 2021 may be related to the larger population size of the large jellyfish and the proliferation of green tides. The investigation provided basic data and fundamental insights for achieving a comprehensive understanding of zooplankton community structure and their long-term dynamics.Keywords：zooplankton community;spatial distribution;global warming;Nemopilemanomurai;Ulvaprolifera9|5|0Updated：2025-02-19
Ecology
- Abstract：Magnetotactic bacteria have been the only known magnetoreceptive microorganisms for decades. Even if the existence of magnetotactic protists was suggested in 1986, this is only 30 years later that magnetotaxis was extended to the domain of Eukaryota, thanks to the characterization of magnetotactic symbiotic assemblies composed of a flagellated protist and bacteria biomineralizing magnetic crystals. Their mutualistic ectosymbiosis relies on a collective magnetotaxis coupled to a hydrogen-based syntrophy. This new form of cooperation challenges our view of magnetic biomineralization in prokaryotes and magnetoreception in eukaryotes. In this review, we present how magnetosymbiosis was discovered and how cooperation functions. Finally, we discuss the future research and the new perspectives such discovery brought to the field of magnetotaxis.Keywords：magnetotaxis;biomineralization;symbiosis;magnetotactic9|6|0Updated：2025-02-19
- Abstract：Abnormal content of protein SEIPIN causes Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) in humans. Previous studies have shown that Arabidopsis thaliana has evolved three SEIPIN homologs, determining the fusion and size of lipid droplets. Nannochloropsis oceanica is a model oleaginous microalga with the accumulation potential of fatty acids. We believe that the SEIPIN homolog if any in N. oceanica should function as it does in humans, plant among others. In this study, we identified a homologous gene of SEIPIN in N. oceanica, constructed a bacterial plasmid containing the elements controlling the transcription of its complete antisense RNA, and integrated the linearized plasmid into the N. oceanica genome. We obtained a transformant in which the abundance of SEIPIN transcript is significantly down-regulated. Flow cytometry analysis showed that the triacylglycerol (TAG) content of the transformant is significantly lower than that of the wild type (WT). Transcriptomic analysis showed that the down-regulation of SEIPIN transcript abundance could affect the protein functioning in endoplasmic reticulum (ER), implying that SEIPIN gene can function in N. oceanica in a similar way to that in A. thaliana.Keywords：Nannochloropsis oceanica;antisense RNA;SEIPIN;neutral lipid9|3|0Updated：2025-02-19
- Abstract：Safety, high protein content, and the numerous health benefits make Spirulina an outstanding source of bioactive peptides. Peptides from Spirulina, which exhibit antioxidant, anti-inflammatory, and antihypertensive effects, may assist in the management of cardiovascular diseases (CVDs). Here, we present the optimization of enzyme-digested hydrolysates derived from Spirulina sp. by using response surface methodology (RSM). We also evaluated the biological activity of Spirulina protein hydrolysates (SPHs) in contributing to the amelioration of hypertension and associated cardiovascular diseases. Our findings suggest that Spirulina protein extracts contain a complex proteinaceous composition with phycocyanin being the dominant protein, as evidenced by both SDS-PAGE and LC-MS/MS profiling. Alkaline protease, protease K, and α-chymotrypsin exhibited a substantial hydrolytic effect on Spirulina protein, taking into account their degree of hydrolysis (DH), peptide yield, and molecular weight distribution. Single-factor experiments identified pH, temperature, and enzyme/substrate ratio as the key factors influencing DH. Moreover, optimal hydrolysis conditions for the proteases were determined via RSM, leading to a considerable enhancement of the actual DH. Bioassays showed that SPHs have strong antioxidant activity against various free radicals, with a higher ability to scavenge hydroxyl radicals. Furthermore, SPHs inhibited macrophage nitric oxide secretion and significantly inhibited angiotensin I-converting enzyme in vitro at 400 μg/mL. It is worth noting that SPHs prepared with protease K exhibited a potent anti-hypertensive effect in vivo. The findings indicate the potential usefulness of including dietary SPHs in preventing hypertension and associated CVDs. This research could be valuable in guiding the development of health-promoting foods within the Spirulina industry.Keywords：antioxidant activity;antihypertensive effect;angiotensin converting enzyme inhibition;response surface methodology;Spirulina6|4|0Updated：2025-02-19
- Abstract：Locations around the equator provide unique habitats for microalgae presumably with exceptional vitality. To develop microalga-derived product systems, we previously created a (sub)tropical microalgal collection. In this study, two Chlorella strains (MEM176 and MEM193), adaptive to typical tropical climate, were isolated from the collection. The production performance was evaluated where both strains showed a robust growth in high temperatures and light intensities. Specifically, the strains MEM176 and MEM193 produced 503.6-mg/(L·d) and 411.3-mg/(L·d) biomass, respectively, with high contents of proteins. Their commercial and nutritional values were emphasized by amino acid compositions (e.g., proline, valine, and phenylalanine). Particularly, higher amounts of proline were revealed in MEM176 (47.9 mg/g dry biomass (DW)) and MEM193 (47.9 and 59.2 mg/g DW) than available commercial strains. Compared with MEM193, MEM176 produced 129.7% more lipids in which unsaturated fatty acids (particularly linoleic acid and α-linolenic acid) account for 65% of the total lipids. Therefore, it is promising to explore the potential of these Chlorella strains as food additives via outdoor cultivation in tropical area, notably MEM176 that exhibits superiority as sources of essential amino acids and valuable fatty acids.Keywords：Chlorella;tropical species;food additive;microalga6|3|0Updated：2025-02-19
- Abstract：17α-methyltestosterone (17α-MT) is an emerging pollutant, which is harmful to the endocrine system and reproduction of fish. We investigated the effects of different concentrations of 17α-MT (0, 5, 30, 60, and 100 mg/kg) on endoplasmic reticulum stress (ERS) and apoptosis in the liver of Takifugu fasciatus. Results show that: (1) with the increase of 17α-MT treatment concentration, liver transaminases (alanine aminotransferase; aspartate aminotransferase) and the mRNA expression of ERS marker genes (glucose-regulated protein 78; calreticulin) of T. fasciatus were significantly increased compared with the control group (P<0.05); (2) the activity of succinate dehydrogenase (SDH), Caspase3 and Caspase9 in the liver of T. fasciatus increased with the increase of 17α-MT concentration compared with the control group (P<0.05); (3) by using 4-phenylbutyricacid (4-PBA) inhibitors to stimulate ERS through in vitro experiments, the expression of ERS and apoptosis-related genes significantly decreased (P<0.05), and the apoptosis rate of T. fasciatus hepatocytes was significantly inhibited (P<0.05) under 17α-MT treatment. This study confirmed that ERS played an important role in the induction of apoptosis in the hepatocytes of T. fasciatus, which enriched the ecotoxicological information of environmental androgens.Keywords：17α-methyltestosterone;Takifugu fasciatus;liver;endoplasmic reticulum stress;apoptosis5|5|0Updated：2025-02-19
- Abstract：Marine fish diversity in the Beibu Gulf from 2014 to 2022 was analyzed, using various methods including at-sea fisheries resource surveys, fishing port surveys, underwater survey techniques, and data from literature, books, and databases, from which 1 059 fish species across 40 orders, 166 families, and 503 genera were identified. Among them, Acanthuriformes displayed the highest diversity, followed by Carangiformes and Perciformes. Notably, eight alien species were found in the Beibu Gulf. The International Union for Conservation of Nature (IUCN) Red List assessment revealed 51 threatened species, primarily cartilaginous fish. Taxonomic changes affected 88.70% of species due to classification adjustments, misidentifications, and junior synonymy. This study contributed new data of the gulf, including one additional order, six new families, 34 new genera, and 81 new species, emphasizing the dynamic nature of marine ecosystems. Fish diversity in the gulf was relatively lower than the broader South China Sea, attributed to limited habitats and survey methods. Different survey methods, such as gill nets, trap nets, and underwater cameras, yielded varying results. Ocean currents may have transported deep-sea species into the Beibu Gulf, leading to accidental records. Research gaps exist in unexplored areas, warranting further investigation. Therefore, the Beibu Gulf hosts significant marine biodiversity, but taxonomic challenges and undiscovered species require new research and conservation efforts.Keywords：northwestern South China Sea;new record;taxonomic change;fish diversity;survey method10|3|0Updated：2025-02-19
- Abstract：The black coral genus Bathypathes Brook, 1889 represents a relatively diverse and ecologically important assemblage comprising the deep-sea hard substrate communities. Recent phylogenetic investigations have revealed the polyphyletic nature of Bathypathes, urging further morphological analysis to understand its systematics. By combing morphological and molecular data, we describe Bathypathes multifurcata sp. nov. and report B. pseudoalternata Molodtsova, Opresko & Wagner, 2022 based on the specimens collected from the tropical western Pacific. The phylogenetic topology reconstructed using nuclear ITS1-5.8S-ITS2 and three mitochondrial fragments suggests the separation of Bathypathes into four groups. Our analysis of morphological characters, particularly the colony branch and pinnule patterns also roughly classify Bathypathes into four morphological groups A–D. Group A is characterized by the unbranched colony and the subopposite arrangement of pinnules. In contrast to Group A, Groups B–D have the alternately arranged pinnules. Among these, Group C exhibits a distinctly long unpinnulated stem compared to Groups B and D. Group B has unbranched colony, relatively short unpinnulated stem, and spines on pinnules have blunt apex. Within Group D, large colonies (higher than 40 cm) have one or a few branches, small colonies (less than 40 cm) are unbranched, and spines on pinnules have acute apex. Further data particularly those species without sequences are necessary to verify the classification of these groups.Keywords：Antipatharia;black coral;taxonomy;phylogeny;seamount;Western Pacific22|7|0Updated：2025-02-19
- Abstract：The conversion process of chitin, one of the abundant biomass resources on the earth, not only follows the principles of green chemistry, but also has significant value in industrial applications. However, it is a great challenge to directly convert insoluble and rigid structured chitin to 5-hydroxymethylfurfural (HMF). To address this issue, we developed a green conversion process combining pretreatment and catalytic system. Chitin was first pretreated by hexafluoro isopropanol (HFIP), which somewhat disrupted the hydrogen bonding network within the chitin structure. Subsequently, formic acid (FA) and silicotungstic acid (STA) synergistically catalyzed the conversion to HMF in a biphasic system of 2-methyltetrahydrofuran (2-Me-THF)/H2O, and high yields (40.2%) HMF was obtained under the optimism conditions. The product distribution was analyzed by HPLC-MS and the co-catalysis of FA with STA was evidenced. A dual-function catalytic system with both Lewis and Brønsted acids was created, the catalytic system that significantly improved the efficiency of complex tandem catalytic reactions with chitin. Based on the experimental results, a possible pathway for chitin conversion was deduced, providing a new catalytic idea for the efficient conversion of chitin to HMF.Keywords：chitin;5-hydroxymethylfurfural;2-Me-THF/H2O biphasic system;Lewis and Brønsted acid4|3|0Updated：2025-02-19
- Abstract：Mussels are common anchoring organisms that adhere to the surfaces of various substrates with their byssus. The adhesion of mussel to substrates is contingent upon the presence of mussel foot proteins, of which Mytilus edulis foot protein-1 (Mefp-1) has been identified as the most abundant protein. It has been found that lipids are involved in the mussel adhesion process and can facilitate Mefp-1 adhesion. In this research, the adhesion behavior of Mefp-1 on various substrate surfaces under the effect of typical seawater cations with or without the presence of lipid were investigated using a quartz crystal microbalance with dissipation (QCM-D). Results indicate that the presence of cations Ca2+, Mg2+, Na+, and K+ leads to varying degrees of reduction in the adhesion performance of Mefp-1 on different substrates. The degree of this reduction, however, was much alleviated in the presence of palmitic acid, which is involved in the mussel adhesion process. Therefore, the involvement of palmitic acid is advantageous for mussel protein adhesion to the substrate surface in the marine environment. This study illustrated the significant contribution of palmitic acid to mussel adhesion, which can help to better understand biofouling mechanisms and develop biomimetic adhesive materials.Keywords：mussel adhesion;quartz crystal microbalance with dissipation (QCM-D);typical seawater cations;palmitic acid;Mefp-14|4|0Updated：2025-02-19
- Abstract：Salinity is recognized as a pivotal factor limiting the migration of freshwater fish to brackish environments. The largemouth bass (LMB, Micropterus salmoides), a globally translocated freshwater fish, exhibits estuarine distribution, yet its hyperosmoregulatory capacity during early ontogenetic stages remains inadequately understood. To investigate the impact of freshwater salinization, a series of experiments were conducted in Guangzhou and Foshan, China. Results reveal that freshwater-activated mature eggs and naturally fertilized oocytes maintained nearly identical osmotic homeostasis, with diameters of 1.38±0.07 mm and 1.37±0.05 mm, respectively. Furthermore, both exhibited peak water excretion at a salinity of 15.0. Remarkably, a reduction in water permeability was observed in hyperosmotic environments. Spontaneous hatching rates increased from 27.5%±14.4% in the 1.0 group to 75.1%±12.0% in the 6.0 group under fluctuating temperature conditions. Yolk-sac LMB larvae consistently reduced survival time from 12.5 d at 1.0 to 50.7±2.1 min at salinity of 35.0. Similarly, more developed larvae also experienced a decrease in survival time. Logistic regression models fitting lethal time with salinity indicated a sharp decrease between 10.0 and 20.0. These findings offer practical insights for predicting distribution patterns and enhancing aquaculture technology for LMB. Moreover, they may contribute theoretically to the broader understanding of the osmoregulatory mechanisms of freshwater fish.Keywords：osmotic homeostasis;acute toxicity;median lethal time;Hatching Rate;dose-response model7|2|0Updated：2025-02-19
- Abstract：Pseudoalteromonas is a group of marine bacteria widespread in diverse marine sediments, producing a wide range of bioactive compounds. However, only a limited number of Pseudoalteromonas phages have been isolated and studied. In this study, a novel lytic Pseudoalteromonas phage, denoted as vB_PalP_Y7, was isolated from sewage samples collected at the Seafood Market in Qingdao, China. vB_PalP_Y7 remained stable across a wide range of temperatures (20–50 ℃) and a wide pH range (3–12). The vB_PalP_Y7 phage harbors a linear double-stranded DNA molecule of 57 699 base pairs (bp) with a G+C content of 45.90%. Furthermore, it is predicted to contain 58 open reading frames (ORFs). Phylogenetic analysis and protein network relationship analysis revealed low similarity between vB_PalP_Y7 and viruses in the ICTV and IMG/VR4 database, suggesting that vB_PalP_Y7 may be a potential new genus, Miuvirus. This study contributed valuable insights to comprehend the relationship between Pseudoalteromonas phages and their host organisms.Keywords：Pseudoalteromonas phage;genomic analysis;phylogenetic analysis;viral cluster8|4|0Updated：2025-02-19
Biology
- Abstract：The early life stages of marine organisms are pivotal in shaping community dynamics and resource availability. In this study, we focused on Portunustrituberculatus, a crustacean integral to China’s fisheries economy, and examined the effect of sea surface temperature (SST) in its critical early life stages on subsequent yields. To analyze the correlation between SST in different larval stages and the corresponding yield of P. trituberculatus, we simulated the transport and distribution of larvae from 2014 to 2022 by employing circulation models and Lagrangian particle tracking experiments (LPTE). In the five years (2014, 2015, 2016, 2019, and 2020), particles were transported in a northwestern direction and moved in the direction of low SST. The distribution of particles in the megalopa stage (M stage) were located in the region of the lower temperature. In 2017, 2018, and 2021, the particles were transported in a northeastern direction but they did not move with the gradient of low SST in these years, and the particles in the last M stage were located in the region where the SST was at the peak of the time period. In 2022, the distribution was observed for most of the particles in the southwestern part of Zhejiang coast, a small part of them were transported in the northwestern direction and a small amount of particles was distributed offshore along the northern area of the Zhejiang coast. The correlations between the SST at each stage of larvae with the corresponding year’s yield showed that the yield of P. trituberculatus decreased significantly (R=0.772, P=0.015) with increasing SST at the M stage. This study preliminarily explains the correlation between SST at the larval stage and the yield of P. trituberculatus and provides essential information for scientific stock enhancement in the future.Keywords：East China Sea;swimming crab (Portunustrituberculatus);larval stage development;Lagrangian particle tracking;spatial-temporal dynamics;Sea surface temperature21|10|0Updated：2025-02-19
- Abstract：The Argentine shortfin squid Illex argentinus is an economically important short-lived species widely distributed in the southwest Atlantic Ocean. The abundance and distribution of I. argentinus are associated with climate change and environmental fluctuations. The potential distribution of I. argentinus was modeled with various environmental variables including sea surface temperature (SST), sea surface height (SSH), chlorophyll a, sea surface salinity (SSS), net primary productivity (NPP), mixed layer depth (MLD), eddy kinetic energy (EKE), and photosynthetically active radiation (PAR) using the maximum entropy (MaxEnt) approach during the peak fishing seasons (January–April). The habitat suitability index (HSI) was defined as the probability of species emergence from the MaxEnt model and the area of HSI
Aquaculture and Fisheries
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