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Latest Issue
Volume 43 ， Issue 6 ， 2025
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- Abstract：Deep learning (DL) has become a crucial technique for predicting the El Niño-Southern Oscillation (ENSO) and evaluating its predictability. While various DL-based models have been developed for ENSO predictions, many fail to capture the coherent multivariate evolution within the coupled ocean-atmosphere system of the tropical Pacific. To address this three-dimensional (3D) limitation and represent ENSO-related ocean-atmosphere interactions more accurately, a novel this 3D multivariate prediction model was proposed based on a Transformer architecture, which incorporates a spatiotemporal self-attention mechanism. This model, named 3D-Geoformer, offers several advantages, enabling accurate ENSO predictions up to one and a half years in advance. Furthermore, an integrated gradient method was introduced into the model to identify the sources of predictability for sea surface temperature (SST) variability in the eastern equatorial Pacific. Results reveal that the 3D-Geoformer effectively captures ENSO-related precursors during the evolution of ENSO events, particularly the thermocline feedback processes and ocean temperature anomaly pathways on and off the equator. By extending DL-based ENSO predictions from one-dimensional Niño time series to 3D multivariate fields, the 3D-Geoformer represents a significant advancement in ENSO prediction. This study provides details in the model formulation, analysis procedures, sensitivity experiments, and illustrative examples, offering practical guidance for the application of the model in ENSO research.Keywords：Transformer model;3D-Geoformer;El Niño-Southern Oscillation (ENSO) prediction;explainable artificial intelligence (XAI);integrated gradient method27|18|0Updated：2025-12-16
- Abstract：Sea surface temperature (SST) is an important ocean variable affecting climate change. It plays an important role in the interactions between the ocean and the atmosphere, and it also has an effect on the transport of heat, freshwater, and carbon. Therefore, accurate SST prediction is necessary for understanding climate change and protecting ocean ecosystems. In this study, we proposed a hybrid model to predict SST in the tropical Pacific Ocean based on two single deep-learning models. Results indicate that the proposed hybrid model shows superior prediction accuracy at all lead times compared to the single model. Specifically, during El Niño periods, the root mean square error, mean absolute error, and Pearson correlation coefficient of the hybrid model forecasts were approximately 0.54 °C, 0.40 °C, and 0.98, respectively, while during La Niña periods, these metrics were 0.55 °C, 0.39 °C, and 0.98, respectively. Notably, the hybrid model was able to capture the spatial distribution of SSTs during the El Niño-Southern Oscillation (ENSO) events more accurately relative to a single model. Moreover, the prediction results of the hybrid model in different ocean regions exhibited lower prediction errors and higher correlations. The ablation experiments showed that sea surface wind (SSW) had different effects on SST at different times. By combining SST and SSW data, the model can make more-accurate predictions under different climatic conditions. The proposed hybrid model is able to predict SSTs quickly and accurately with better robustness during ENSO.Keywords：sea surface temperature (SST);deep learning;hybrid model;prediction;tropical Pacific Ocean17|13|0Updated：2025-12-16
- Abstract：Bottom marine heatwaves (BMHWs), i.e., anomalous ocean warming at the seafloor, can happen without concurrent surface marine heatwaves (SMHWs), which pose a serious threat to marine ecosystems and present a challenge to detect and study them adequately. This type of event is called independent BMHWs. This study examines the summertime BMHWs on the continental shelf of the East China Sea (ECS) using oceanic reanalysis data from 1993 to 2020. Our results show that summertime BMHWs in the ECS are generally more intense than SMHWs, with some BMHW events occurring without surface expression. Through heat budget analyses of the 2016 SMHW event and the 2019 BMHW event, we investigated the drivers of independent summertime BMHWs. It is indicated that the occurrences of bottom temperature anomalies in summer are predominantly attributed to oceanic horizontal advection. Specifically, the summertime BMHWs on the central ECS shelf are closely related to the strengthening of the inshore branch of the Taiwan Warm Current (TWC) and the weakening of the offshore TWC branch. These findings provide important insights into the underlying physical processes and diagnostic tools for monitoring and managing independent BMHWs in the ECS.Keywords：bottom marine heatwave (BMHW);East China Sea (ECS);Taiwan Warm Current (TWC);oceanic horizontal advection12|16|0Updated：2025-12-16
- Abstract：Marine heat waves (MHWs), characterized by extreme warm sea surface temperature events, frequently occur in Chinese marginal seas. However, the seasonal variation and joint distribution of MHWs in the Bohai Sea have not been fully described. Therefore, we conducted a systematic investigation of MHWs in this region. Our findings indicate that the frequency of MHW is low during winter, with long duration and weak intensity, while in summer, it is opposite, being high in the frequency, and shorter but stronger. Notably, in summer, the Laizhou and Liaodong bays exhibit a relatively long total day of MHWs compared to other areas in the Bohai Sea. Furthermore, our analysis of the joint distribution of MHWs, considering both duration and intensity, reveals significant seasonal variations. To provide practical insights for marine ranching, we have also investigated time series of MHWs at several specific stations and computed the correlation coefficients between MHW intensity and potential influential factors. Results suggest that sea surface height, cloud cover, wind stress, and wind stress curl are significantly correlated with MHW intensity, although these relationships vary geographically and seasonally. Overall, these findings elucidate the seasonal variation and potential influential factors of MHWs in the Bohai Sea and offer insights for decision-making and planning in marine ranching.Keywords：marine heat wave (MHW);sea surface temperature (SST);seasonal variation;Bohai Sea (BS);correlation coefficient;marine ranching8|17|0Updated：2025-12-16
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Construction of the sea surface wind field of Typhoon Chaba based on wind field model and CMEMS data
Abstract：Typhoon Chaba was the most intense typhoon to strike western Guangdong since Typhoon Mujigae in 2015. According to the National Disaster Reduction Center of China, in the morning of July 7, 2022, over 1.5 million people in Guangdong, Guangxi, and Hainan were affected by Typhoon Chaba. The typhoon also caused the “Fukui 001” ship to be in distress in the waters near Yangjiang, Guangdong, on July 2, resulting in big casualties. Studies have indicated that wind field forecast for Typhoon Chaba was not accurate. To better simulate typhoon events and assess their impacts, we proposed the use of a model wind field (Fujita-Takahashi) integrated with the Copernicus Marine and Environmental Monitoring Service (CMEMS) data to reconstruct effectively the overall wind field of Typhoon Chaba. The simulation result aligns well with the observations, particularly at the Dashu Island Station, showing consistent trends in wind speed changes. However, certain limitations were noted. The model shows that the attenuation of wind speed is slower when typhoon neared land than that observed, indicating that the model has a high simulation accuracy for the ocean wind field, but may have deviations near coastal areas. The result is accurate for open sea but deviated for near land due to the land friction effect. Therefore, we recommend to adjust the model to improve the accuracy for near coasts.Keywords：typhoon sea surface wind field;Typhoon Chaba;fusion wind field model;Copernicus Marine and Environmental Monitoring Service (CMEMS) wind field data14|14|0Updated：2025-12-16
Physics
- Abstract：Early Cambrian organic-rich shales in the Yangtze Plate are key shale gas exploration targets in China, but their sedimentary environments are not well understood. This lack of knowledge complicates the evaluation of these targets and associated risks. Assessing shale depositional environments is also challenging due to the fine-grained nature of the sediments and subtle compositional variations. Herein, marine black shales of the Lower Cambrian Shiyantou (SYT) Formation (Fm) and Yu’anshan (YAS) Fm are investigated through a series of experiment, including thin sections, scanning electron microscopy, and major and trace elements analysis. Results show that five lithofacies can be identified in the SYT and YAS shales: (1) calcareous mudstone; (2) wavy-laminated sand, silt, and clay bearing mudstone; (3) laminated and massive mudstone; (4) planar-laminated pyritic mudstone, and (5) thin bedded sand and siltstone. Average content of major elements SiO2, Al2O3, MgO, Fe2O3, K2O, CaO, Na2O, TiO2, P2O5, and MnO of SYT Fm are 57.03%, 12.74%, 4.20%, 3.97%, 3.93%, 3.35%, 1.09%, 0.68%, 0.28%, and 0.05%, respectively. Average content of major elements SiO2, Al2O3, MgO, Fe2O3, K2O, CaO, Na2O, TiO2, P2O5, and MnO of Yu’anshan Fm are 54.93%, 14.52%, 5.26%, 6.00%, 3.77%, 3.88%, 0.15%, 0.63%, 0.19%, and 0.10%, respectively. Samples from SYT Fm are enriched in Li, V, Cr, Co, Zr, Cs, and U relative to Upper Continental Crust (UCC) and most of shale samples from YAS Fm are enriched in Li, V, Co, and U relative to UCC. The marine black shales are deposited in dynamic anoxic to oxic environment in upper Yangtze Plate, which indicated the seabed had already oxidized in the Cambrian Stages 2 and 3. The Chemical Index of Alteration (CIA) values ranged 51.84–79.46 indicate a warm and humid climate in the 2 stages. These findings are consistent with the region’s paleogeography and previous studies. They hold significance for sedimentologists, paleontologists, and other researchers involved in petroleum geology.Keywords：Lower Cambrian;shale lithofacies;depositional environment;redox condition;palaeo-climate9|16|0Updated：2025-12-16
Geology
- Abstract：The intertidal zone of mangroves has a significant impact on the ecological environment by serving as a crucial habitat for a wide range of organisms. When assessing heavy metal contamination in sediments within this zone, it is essential to establish a regional geochemical baseline that accounts for natural variations. In this study, regional geochemical baselines of heavy metals were established based on core sediment samples collected from Dongzhai Harbor in November 2015. Linear regression analysis was employed to examine the correlations between heavy metals and potential normalized elements. Subsequently, the sediment quality and intensity of pollutant input in the sediments of a mangrove intertidal zone were evaluated with enrichment factor (EF) and excessive influx of heavy metals. The EF values for Cr, Cd, Pb, Zn, and Ni in the study area were all below 1.5, indicating minimal levels of contamination; however, minor Cu contamination was observed in the high tidal flat area due to potential terrestrial inputs. These findings suggest that the overall environmental quality about heavy metals was good within the intertidal zone of mangroves. Moreover, as for the excess fluxes of heavy metals in intertidal sediments, there was consistency between influence and intervention of human activities on sedimentary environment during the selected period when examining variation trends.Keywords：mangrove intertidal zone;sediment;geochemical baseline;heavy metal contamination risk assessment31|12|0Updated：2025-12-16
- Abstract：The flux of dissolved inorganic nitrogen (DIN), predominantly nitrate (
- Abstract：Silicon (Si) is an important element in aquatic ecosystems. Based on the observed data in the Huanghe (Yellow) River Basin, a forward model was used to evaluate the silicate weathering rate in the Huanghe River Basin. The effects of silicate weathering, damming, and land use change on the Si concentration and flux were analyzed. Results show that the dissolved Si (DSi) concentration decreased first and then increased, and was 0.82–2.96 mg/L. As a silicon source in the Huanghe River Basin, the silicate weathering rate in the upper reaches of Lanzhou was high, and a large amount of DSi was transported to the lower reaches. Agricultural irrigation in the middle reaches caused a large amount of DSi loss, and the interception of large-scale cascade reservoirs caused a large amount of DSi retention. The DSi released by sediment re-suspension due to high runoff scouring in the downstream channel also served as a silicon source to supplement the DSi flux transported to the sea. Suspended particulate matter and biogenic Si (BSi) increased first and then decreased in the ranges of 24.1–1 590.7 mg/L and 0.08–2.17 mg/L, respectively, due mainly to severe soil erosion in the eastern Loess Plateau, which caused significant amounts of phytoliths to enter the water.Keywords：biogenic Si (BSi);dissolved Si (DSi);Huanghe River;sediment;silicate weathering6|13|0Updated：2025-12-16
Chemistry
- Abstract：The environmental impact of microplastic pollution has triggered the alarm of public for over 20 years. The South China Sea, situated as a marginal sea in the tropical region, is surrounded by unique blue-carbon ecosystems and densely populated provinces that produce a substantial amount of industrial plastic waste. Understanding the source-sink relationship and distribution of microplastics in rivers, nearshores, and estuaries is crucial for safeguarding the ecological integrity of estuarine environments. In this review, a comprehensive review of recent researches on the distribution and source-sink relationships of microplastics in rivers and nearshore and offshore regions in the South China Sea have been discussed. Due to atmospheric deposition and precipitation, microplastics exhibit spatial heterogeneity in terms of abundance and distribution in areas surrounding the South China Sea. The major pollution sources include river inputs, industrial wastewater discharge, aquaculture activities, and shipping operations. Anthropogenic and other biological factors such as fish ingestion and vegetation entrapment also affect the distribution and transport of microplastics. To quantify the abundance and distribution of microplastics and elucidate their transport mechanisms, it is recommended to strengthen the detection and management of microplastics in the South China Sea region, standardize sampling methods and units, establish shared databases, and explore effective governance pathways.Keywords：microplastic;sediment;mangrove;South China Sea;coral reef48|15|0Updated：2025-12-16
- Abstract：The widespread production and use of plastic products have highlighted the ecological risks of microplastics (MPs). MPs, mainly as microfibers (MFs), can carry various pollutants, and their properties may change over time, potentially affecting their interactions with pollutants. This study aims to compare the combined toxicity effects of virgin and aged MFs with the common heavy metal copper (Cu). Gibel carp Carassius auratus gibelio were exposed to 1 mg/L of virgin and aged polyacrylonitrile MFs (PanMfs) separately and in combination with Cu (0.5-mg/L copper sulfate) for 21 d. Results show that both aged and virgin PanMfs significantly reduced Cu accumulation in gibel carp, with no notable difference. Cu adversely affected the carp’s intestine and liver, while PanMfs alone had minimal histological impact but notably mitigated intestinal damage caused by Cu. Enzyme activity and gene expression analysis indicated that both PanMfs and Cu exposure, alone or combined, compromised gibel carp’s antioxidant capacity, digestive and liver functions, induced inflammation, and affected liver metabolism and intestinal immune response. Integrated biomarker response analysis of enzyme activity and gene expression showed that combined Cu and PanMfs exposure had a stronger impact on gibel carp than individual exposure. However, whether exposed individually or in combination, aged PanMfs had a slightly greater impact than virgin PanMfs. This study showed that PanMfs alone exhibit minimal toxic effects on gibel carp but significantly modify Cu toxicity, with negligible differences between aged and virgin PanMfs except for slight disparities in enzyme activity and gene expression.Keywords：microplastic;virgin/aged microfiber;copper;toxicity;Carassius auratus gibelio83|4|0Updated：2025-12-16
- Abstract：Nanoplastics (less than 1 µm in size, NPs) have emerged as a significant pollutant in aquatic environment, posing considerable threats to freshwater biota. However, the mechanisms through which NPs modulate the predation responses of these organisms remain poorly elucidated. We investigated the impacts of polystyrene NPs, characterized by a representative particle size (diameter: 50 nm; concentration: 0–8 μg/L), on the anti-predation defense mechanisms of mature rotifer Brachionus calyciflorus against predator of rotifer Asplanchna brightwellii, utilizing transcriptomics to unravel the underlying molecular pathways. Results reveal that the posterolateral spine length and type of B. calyciflorus serve as robust indicators of defensive morphology, even in the presence of NPs exposure. Specifically, increasing concentrations of NPs and predator cues suppressed the defensive responses, which was associated with morphological transformations. This suppression was associated with the down-regulation of the HIF-1α signaling pathway, implicating potentially its role in modulating fight-or-flight responses. Furthermore, we identified functional crosstalk among multiple signaling pathways, including HIF-1α, PI3K-Akt, FoxO, and mTOR, in B. calyciflorus, which may underpin the organism’s responses to polystyrene NP exposure. These findings contribute to the advancement of predictive models to assess the ecological risks posed by polystyrene NPs contamination in aquatic ecosystems.Keywords：rotifer;Brachionus calyciflorus;inducible defense;Asplanchna kairomones;nanoplastic;transcriptome75|12|0Updated：2025-12-16
- Abstract：Environmental fluctuations are a pervasive natural phenomenon that typically favor diverse maternal investment strategies. Organisms across various evolutionary lineages have acquired the ability to enter the dormancy state to tolerate conditions that are unsuitable for normal life activities. In cyclical parthenogenesis, sexual reproduction is generally linked with dormancy, thereby enhancing the long-term fitness of populations through positive feedback mechanisms. This study evaluates the impact of environmental variability on offspring population dynamics through sexual reproduction in the rotifer Brachionus calyciflorus. We found that mictic females (sexual females) exposed to low-predictability environments produced resting eggs with a sporadic hatching pattern, reduced hatching rate, and smaller sizes of resting egg, embryo, and stem females, while increasing variations in fertilization among individuals to maximize population fitness. Variations in population growth could be manifested in enhanced reproductive capacity 2–3 d post-hatching, along with differences in fecundity among individuals. This suggests that dormant eggs from unstable environments may prioritize offspring survival and adjust to increased fertilization among individuals. This adaptive strategy enables rotifer populations to rapidly adjust to environmental changes, thus avoiding extinction and thriving in diverse habitats. Our systematic study enhances the understanding of how environmental stability affects long-term population fitness in cyclical parthenogens.Keywords：environmental stability;maternal effect;sexual reproduction;population regulation;Brachionus calyciflorus;zooplankton6|6|0Updated：2025-12-16
- Abstract：Ostreopsis cf. ovata is a marine benthic dinoflagellate in tropical and temperate seas and can produce potent toxic compounds. The existence of O. cf. ovata has been found in the Chinese coastal areas, but studies on its toxicity are very few. This study investigated the toxicity of the O. cf. ovata (TIO991) isolated from Weizhou Island in the South China Sea by using methanol and chloroform to extract toxic compounds from the algal cells cultured indoor. Experiments on mouse acute toxicity showed that the crude methanol extract (CME) of O. cf. ovata caused the death of mice in 16–18 min. Furthermore, CME inhibited the cell reproduction of human neuroblastoma cells (BE (2)-M17 cells) by Cell Counting Kit-8 with a dose- and time-effect relationship and caused cell death in the form of cell necrosis. We found that CME had strong hemolytic activity and was significantly inhibited by ouabain, indicating that CME might contain palytoxins. By contrast, the crude chloroform extract of O. cf. ovata was relatively weak in toxicity as obtained in our experiments on mouse acute toxicity, cytotoxicity, and hemolytic activity. This suggests that the algae may raise the potential threat to marine ecosystems and public health.Keywords：Ostreopsis cf. ovata;hemolysis neutralization assay;cytotoxic activity;mouse bioassay7|6|0Updated：2025-12-16
- Abstract：The global rise in CO2 concentration is having a profound impact on the structure and function of aquatic ecosystems. However, little information is available on the responses of odor-producing cyanobacteria to the increase in CO2 concentration. In this study, the effects of different CO2 concentrations on 2-methylisoborneol (MIB)-producing Pseudanabaena and non-2-MIB-producing Pseudanabaena under monoculture and co-culture conditions were investigated. Results show that the specific growth rate of Pseudanabaena gradually increased with the rise in CO2 concentration, and for the 2-MIB-producing strain, this increase was significantly higher than the non-2-MIB-producing strain. Under co-culture conditions, the proportion of non-2-MIB-producing Pseudanabaena was significantly higher than that of 2-MIB-producing Pseudanabaena, suggesting a superior competitive ability of non-2-MIB-producing Pseudanabaena over 2-MIB-producing Pseudanabaena. Under monoculture conditions, the total 2-MIB production at the 300-μg/g CO2 concentration was significantly higher than that at 600- and 1 200-μg/g CO2 concentrations. The 2-MIB concentration produced by Pseudanabaena decreased with the increasing in CO2 concentration. Therefore, we believe that with the future increase in CO2 concentration, 2-MIB concentration would be decreased and so would the risk of 2-MIB outbreaks.Keywords：odor-producing algae;2-methylisoborneol (MIB);Pseudanabaena;CO2 concentration;competition7|8|0Updated：2025-12-16
- Abstract：Shallow lakes of the middle-lower reaches of Changjiang (Yangtze) River are a globally unique ecosystem essential for the regional sustainable economic development. These lakes have recently been under pressure from both human activities and climate change, underscoring the need for research on their ecological health and drivers. However, most previous studies focused on large lakes (i.e., over 500 km2) and limited ecological elements, such as nutrient levels. Caizi Lake, a relatively small (approximately 226 km2), a Changjiang River-isolated shallow lake, was chosen as a case of study. We assessed its ecological health and analyzed the driving forces using an integrated dataset from in situ observations, remote sensing, and historical data. Our findings indicate that in 2023, the mean ecological health score, reflecting from all selected elements—algal bloom area, zooplankton, macroinvertebrates, macrophytes coverage, comprehensive trophic level index, and biodiversity—was 50.4 out of the maximum of 100. Notably, the ecological health scores for macrophytes coverage (1.9), macroinvertebrates (17.2), and biodiversity (44.0) were particularly low. In 1960–2007, the ecological health was deteriorated as the macrophytes coverage was dropped from 80% to 50%. The degradation of macroinvertebrate communities and a decrease in biodiversity might be primarily due to the eutrophication-induced abnormal algal proliferation. In 2007–2023, elevated water levels might degrade the macrophytes coverage and other aspects of ecological health. Therefore, we proposed an ecological health restoration plan for Caizi Lake focusing on nutrient reduction and water level regulation on the thresholds of total nitrogen and phosphorus concentrations, an and provided a reference for the protection of Caizi Lake and other cases having similar hydromorphic background.Keywords：shallow lake;algal bloom;eutrophication;ecological health;macrophyte6|5|0Updated：2025-12-16
Ecology
- Abstract：The mud crab (Scylla paramamosain) has been successfully cultivated in chloride-type low-salinity alkaline waters, yet the molecular mechanisms underlying its adaptation to this environment remain elusive. This study seeks to uncover the adaptation mechanisms of the antennal gland of mud crab under acute chloride-type low-salinity alkaline water stress. Three-hundred crabs were randomly selected and divided into two groups: the low salinity (LS, salinity of 2.2) group and the control group (CK, salinity of 23.4). Following a 120-h experimental period, the antennal glands were sampled for transcriptomic analysis. Experimental results show that acute chloride-type low-salinity saline-alkaline water stress led to a significant decline in the survivorship of mud crab. Through comparative transcriptomic analysis, we identified 923 differentially expressed genes (DEGs), among which 272 were upregulated and 651 were downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that the majority of these DEGs are closely linked to functions such as energy metabolism and osmoregulation. Notably, the pathways involving oxidoreductase activity, oxidative phosphorylation, symporter activity, and intracellular calcium-activated chloride channels were significantly enriched, highlighting their pivotal roles in enhancing the osmoregulatory capacity of mud crab and maintaining internal homeostasis in chloride-type low-salinity alkaline environments. Additionally, the upregulation of genes such as SLC6A9, SLC6A4, and FH further facilitated transmembrane ion transport and energy metabolism, thereby reinforcing intracellular isosmotic regulation. However, these controls also pose a potential risk of oxidative stress. Therefore, the antennal gland plays a crucial role in the response of mud crab to acute chloride-type low-salinity alkaline water stress. This study provides new insights into the adaptive mechanisms of mud crab and lays a theoretical foundation for enhancing chloride-type low-salinity alkaline water aquaculture techniques.Keywords：Scylla paramamosain;chloride-type low-salinity alkaline water;antennal gland;transcriptome;osmoregulation6|7|0Updated：2025-12-16
- Abstract：Endoplasmic reticulum (ER) stress and Ca2+ homeostasis play important roles in the environmental adaptation of aquatic animals. To elucidate the response and correlation of ER stress and Ca2+ homeostasis in the gills of Penaeus vannamei under ammonia stress, we investigated the expression levels of genes related to ER stress and Ca2+ homeostasis in the gills of P. vannamei exposed to 0- (control), 3.8-, 7.6-, and 11.3-mg/L total ammonia nitrogen for 96 h. Results show that the relative gene expression levels of the ER stress indicators Bip, eiF2α, ATF4, IRE1, and XBP1s were higher in the stress groups than in the control group at 12 and 48 h, reaching the maximum at 48 h (P<0.05). However, at 96 h, the levels of these indicators were lower in the 7.6- and 11.3-mg/L groups than in the control group. The relative expression levels of SERCA, RyR, MCU, and Letm were significantly higher in the stress groups than in the control group at 12, 24, and 48 h (P<0.05), and the expression levels were positively correlated with the ammonia stress concentration. At 96 h, the expression levels of SERCA in the stress groups were lower than that in the control group, whereas the expression levels of RyR in the stress groups were significantly higher than that in the control group (P<0.05). The relative expression levels of MCU were not significantly different from those in the control group. The relative expression levels of IP3R in the 7.6- and 11.3-mg/L groups were significantly lower than that in the control group during the ammonia stress period (P<0.05). Pearson’s correlation analysis showed significant correlations among NH3-N levels, the expression of ER stress indicator genes, and the expression of genes related to the regulation of Ca2+ homeostasis. The above results indicate that ammonia stress could induce ER stress, and consequently changed the mitochondrial and ER Ca2+ homeostasis in the gills of P. vannamei, which contribute to its adaptive mechanisms under adverse environmental conditions.Keywords：Penaeus vannamei;gill;ammonia stress;Ca2+ homeostasis;endoplasmic reticulum (ER) stress6|7|0Updated：2025-12-16
- Abstract：The order Watanabeales (Trebouxiophyceae, Chlorophyta) was established in 2021 to include unicellular coccoid green algae but its species diversity must be further explored. The genus Jaagichlorella (Watanabeales) currently encompasses nine species and two varieties. In this study, strain FACHB-3637 was isolated from tree bark in Yunnan Province, China. A polyphasic approach combining molecular phylogenetic analyses and morphology was used to investigate the strain. The results reveal that strain FACHB-3637 represents a new lineage within the genus Jaagichlorella, and we propose it as a new species, Jaagichlorella menglunensis sp. nov. Additionally, we report the complete mitochondrial genome of this new species and present a comparative analysis of the mitochondrial genomes in the genus Jaagichlorella. The analysis reveals substantial differences in mitochondrial genome size, structure, and gene composition among J. menglunensis, J. hainangensis, and J. roystonensis.Keywords：Jaagichlorella;mitochondrial genome;morphology;phylogeny;Trebouxiophyceae9|7|0Updated：2025-12-16
Biology
- Abstract：Mass mortality of mandarin fish (Siniperca chuatsi) due to infectious spleen and kidney necrosis virus (ISKNV) infection occurs frequently. Since there are no effective drug treatments available, prevention relies heavily on detection. Effective and rapid on-site detection methods are needed for early diagnosis of ISKNV. In this study, a rapid and simple colloidal gold test strip method, specific for the antibody against major capsid protein (MCP), was developed and systematically evaluated for the detection of ISKNV. The limit of detection of the test strip is a 1꞉100 dilution of a positive standard serum and the antibody level in the fish could be estimated from the depth of color of the test line. The strips were tested against serum samples of cyprinid herpesvirus-2 (CyHV-2), grass carp reovirus (GCRV), largemouth bass ranavirus (LMBV), large yellow croaker iridovirus (LYCIV), and spring viremia of carp virus (SVCV), yielding no cross-reactivity. In addition, 10 mandarin fish artificially infected with ISKNV were tested using the current industry standard PCR method (SC/T 7211-2011) on their splenorenal tissues. The results from the test strips showed a high degree of concordance with PCR testing, achieving a Kappa value of 0.737. All the results indicated that the colloidal gold test strips prepared in this study could be used as a simple, rapid, and highly sensitive and specific method for ISKNV diagnosis.Keywords：infectious spleen and kidney necrosis virus (ISKNV);major capsid protein;antibody;colloidal gold test strip;on-site testing7|4|0Updated：2025-12-16
- Abstract：Global warming underscores the urgent need to enhance carbon sinks to mitigate climate change, yet the role of coastal shellfish aquaculture area as either carbon sinks or sources remains unclear. In this study, we conducted high-resolution profiling observations of CO2 dynamics and net community production (NCP) in a mussel farm located in the Changjiang (Yangtze) River estuary (CRE) during early autumn. Results indicate that the partial pressure of CO2 (pCO2) in the water column was consistently higher than the atmospheric level, averaging 74.75±2.44 Pa, signaling that the mussel farm acted as a CO2 source. The average air-water CO2 exchange flux (
- Abstract：Owing to the extreme rainfall and evaporation events under the changing climate, coastal zones are experiencing salinity fluctuations that stress aquatic organisms. However, the biological consequences of ongoing alteration in salinity levels on euryhaline organisms remain inconclusive. Herein, we sought to uncover how variation in salinity level adversely alters the bacterioplankton community, the gut microbiota of euryhaline shrimp Penaeus monodon, and subsequent shrimp disease risk. To mimic the extreme weather that induces abrupt changes in coastal water salinity, three salinity levels (10, 20, and 30) were selected to investigate the differences in shrimp gut microbiota using bacterial 16S rRNA gene sequencing. Results shows that salinity level and days post experiment (dpe) respectively constrained 45.9% and 13.0% of the variance in the gut bacterial communities. Particularly, abnormal salinity levels accelerated temporal turnover rate, disrupted gut network stability, augmented average variation degree, and increased pathogenic potential in the gut microbiota of shrimp reared at 10 and 30 salinities compared with 20 salinity controls. These changes were accompanied with the shifts in the gut microbiota-mediated functions, especially the compromised immunity and elevated infectious diseases potentials, thereby increasing shrimp disease risk. In addition, abnormal salinity levels increased the role of homogeneous selection governing the gut microbiota. After excluding the dpe-effect, we screened 35 gut salinity-discriminatory taxa that quantitatively discriminated the salinity levels where shrimp were reared, with overall accuracy of 91.1%. Collectively, abnormal salinity levels profoundly disrupt the structure, stability, assembly, and functions of the gut microbiota, which in turn increased disease risk in shrimp. In addition, gut symbionts sensitively responded to the changes in external salinity level. These findings deepened our understanding on the biological consequence of abnormal salinity levels on shrimp health.Keywords：Penaeus monodon;abnormal salinity level;gut microbiota;ecological process;disease risk7|5|0Updated：2025-12-16
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Aquaculture and Fisheries
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