Journal of AAPOS

Endoplasmic reticulum (ER) homeostasis is vital to cell physiological functions. Glucose-regulated protein 78 (GRP78) is a molecular chaperone considered a sensor of ER stress and participates in maintaining ER homeostasis. However, very few studies have provided detailed descriptions of crustacean GRP78 genes. The complete coding sequence of the GRP78 of Neocaridina denticulata sinensis was obtained and termed NdGRP78 in this study. Sequence analysis showed that the open reading frame of NdGRP78 encodes a protein of 656 amino acid residues, and the encoded protein includes three heat shock proteins 70 (HSP70) family conservational motifs, one ATP/GTP binding site A, and one ER homolog region. Multiple sequence alignments demonstrated that the sequences of these key protein functional domains were highly conserved. Phylogenetic analysis revealed that the NdGRP78 protein belongs to a member of the HSP70 family. The NdGRP78 mRNA was detected in all tested tissues by realtime fluorescence quantitative PCR (qPCR), suggesting that the NdGRP78 mRNA was the constituent expression in N. denticulata sinensis. The in-situ hybridization result showed that the expression of NdGRP78 mRNA occurred in all types of hepatopancreas cells. Furthermore, the NdGRP78 expression was significantly increased when shrimp were transferred into Vibrio parahaemolyticus-EGFP infected conditions, low or high temperature, and hypoxia. The above results indicate that NdGRP78 expressions were associated with stress responses. This study provided a theoretical support to the good understanding of the role of NdGRP78 in response to different types of environmental stress tolerance.

Numerical models are crucial for quantifying the ocean-atmosphere interactions associated with the El Niño-Southern Oscillation (ENSO) phenomenon in the tropical Pacific. Current coupled models often exhibit significant biases and inter-model differences in simulating ENSO, underscoring the need for alternative modeling approaches. The Regional Ocean Modeling System (ROMS) is a sophisticated ocean model widely used for regional studies and has been coupled with various atmospheric models. However, its application in simulating ENSO processes on a basin scale in the tropical Pacific has not been explored. For the first time, this study presents the development of a basin-scale hybrid coupled model (HCM) for the tropical Pacific, integrating ROMS with a statistical atmospheric model that captures the interannual relationships between sea surface temperature (SST) and wind stress anomalies. The HCM is evaluated for its capability to simulate the annual mean, seasonal, and interannual variations of the oceanic state in the tropical Pacific. Results demonstrate that the model effectively reproduces the ENSO cycle, with a dominant oscillation period of approximately two years. The ROMS-based HCM developed here offers an efficient and robust tool for investigating climate variability in the tropical Pacific.

Contamination of microplastics (MPs) and their associated plastic additives in the marine environment is a global concern due to their widespread distribution and toxicity to aquatic life. Although polyvinyl chloride (PVC) materials are commonly used in aquaculture environments, the potential risks of PVC MPs and the release of their additives in aquatic environments and organisms remain largely unknown. In this study, we investigated the leaching behaviors of phthalate esters (PAEs), including the mass and composition of PAEs in PVC MPs and their leaching kinetics, and evaluated the environmental risks of using PVC canvas in aquaculture activities. It was found that diethyl phthalate (DEP) was the most dominant PAE compound leached from PVC MPs (44.70±7.87 ng/g), followed by dimethyl phthalate (DMP, 24.40±1.56 ng/g). The Elovich model was applied to simulate the leaching kinetics, and the simulated curves showed similar logarithmic trends that PAEs rapidly migrated from MPs to the water column at first and followed by a gradual increase over time. The different leaching kinetics of PAEs can be explained by their chemical properties, such as water solubility, molecular weight, and octanol-water partition coefficient. Compounds with lower solubility showed higher leaching coefficients, which are the constants of different PAEs in Elovich equation. Considering the potential joint toxicity of PVC leachates and the importance of food security, it is recommended to use PVC products responsibly and manage plastic waste properly.

The Yangtze Plate (YP) and the North China Plate (NCP) are key components of the East Asian continent, and their collision significantly influences the tectonic evolution of the eastern Asian continental margin. As the South Yellow Sea is located at the convergence of these plates, it becomes a pivotal area for understanding the tectonic evolution of East Asia. The characteristics and provenance of clastic rocks of the Middle Permian-the Early Triassic were analyzed and the strata in the Central Uplift including the Qinglong Formation (T1q) and Talung Formation (P3d), consisting of various mudstones and sandstones, were anatomized. Results show that quartz and feldspar are the main diagenetic minerals, while illite and chlorite show signs of secondary alterations. Geochemical imprints indicate a gradual shift in provenance from ancient sedimentary and mafic igneous rocks to intermediate igneous rocks. In the meantime, the tectonic background transformed from continent to continental island arc from the Middle Permian to the Early Triassic. Therefore, we inferred that a soft collision between the North China Plate and the Yangtze Plate likely occurred during the Late Permian, resulted in intensified collision between two plates in the Early Triassic, and shaped the South Yellow Sea. This study provided valuable information on the timing of plate collisions in the South Yellow Sea.

This study explored the morphological characteristics and differences of the otoliths in three native species, Schizothorax biddulphi, S. eurystomus and S. curvifrons, in the Yarkand River of the Tarim River, Xinjiang, China. A total of 93 specimens (27 S. biddulphi, 39 S. eurystomus, and 27 S. curvifrons) were analyzed using six basic otolith morphological parameters (OA, Rmax, Rmin, OP, OL, OW) to derive six factors (F1, F2, F3, F4, F5, F6) and seven indices (RO, FF, CI, RE, EL, RR, AR) for morphological assessment. A discriminant analysis incorporating 77 Fourier coefficients of the otoliths revealed distinct morphological differences among the species. A significant power function relationship between otolith morphology and standard length was observed across the species, with R2 values ranging from 0.409 to 0.749. Principal component analysis (PCA) of 7 traditional otolith morphological indicators explained 81.243% of the variance, yielding an overall species discrimination rate of 81.65%. Further PCA of 77 Fourier harmonic values enhanced the discrimination accuracy, with the first 3 components accounting for 77.49% of the total variation and an improved discrimination rate of 100.00%. Cluster analysis resulted in the grouping of S. biddulphi and S. curvifrons together and revealed their association with S. eurystomus, indicating notable morphological distinctions. Both otolith shape indices and elliptical Fourier analysis have been useful in distinguishing the phenotypic units of different fish species. In this study, otolith morphology was applied for the first time to identify Schizothorax species, providing an in-depth description of species distribution and evolutionary history. This study provides a reference for the identification and systematic classification of Schizothorax species and a scientific basis for formulating effective species protection measures, for promoting the sustainable management of species and important habitats.

Two new species of superfamily Sphaerolaimoidea: Sphaerolaimus obesus sp. nov. and Pseudosteineria articulata sp. nov. are described from the Yellow Sea. Sphaerolaimus obesus sp. nov. is characterized by body stout, cuticle finely striated with lateral alae, outer labial sensilla and cephalic sensilla papilliform, eight bunches of subcephalic setae different in length, amphidial fovea situated at the level of buccal cavity, spicules arcuated with proximal end cephalated, gubernaculum with dorsal-caudal directed apophysis different in shape, seven precloacal papilliform supplements, tail conico-cylindrical with three terminal setae. Pseudosteineria articulata sp. nov. is characterized by cuticle distinctly annulated with lateral alae, six outer labial setae jointed, eight rows of subcephalic setae present, two rows of long somatic setae scattered along lateral alae, amphidial fovea posterior to subcephalic setae, spicules curved and jointed with proximal end with large manubrium, gubernaculum slightly funnel-shaped, tail conico-cylindrical. Phylogenetic analysis based on combined rDNA sequences place Sphaerolaimus obesus sp. nov. and Pseudosteineria articulata sp. nov. within family Sphaerolaimidae and Xyalidae, respectively. Relationships analysis within the superfamily Sphaerolaimoidea shows Sphaerolaimidae as a sister clade to Xyalidae and genera of Xyalidae as paraphyletic clades.

Marine pollution is a well-recognized phenomenon that has many negative effects on the marine environment. The effects of marine pollution are due to the discharge of hazardous materials, toxins, or other pollutants into the marine environment, which includes seas, estuaries, oceans, and other water bodies, and this unwanted input affects the blue economy. The blue economy, which includes industries and research associated with marine and ocean resources, is often affected by marine pollution on multiple levels, such as economic costs, direct resource impacts, health risks, and infrastructure damage. In one report, the pollution-related issues in many countries were estimated at 9 t/inh and cleanup costs between $12 to $160/t. More extensive pollution mitigation projects might take up to 15 years to conclude and cost up to $500/t. To better understand the role of marine pollution and its impact on the blue economy, some key parameters are discussed as follows: the role of biofouling, volatile organic compounds, the impact of metals, anionic pollutants, and antifouling coatings. The review findings also highlight the impact of marine pollution on ecosystems and associated economic activities, which could be reduced through measures such as better international cooperation, waste management, and the development of sustainable practices. Related information on the strategies and policies that could be adopted for sustainable blue economy are stated after each section.

Three new free-living marine nematodes belong to the order Enoplida from the Yellow Sea, China are described. The first new species, Halanonchus gracilis sp. nov. is characterized by inner labial sensilla papillose, outer labial setae and cephalic setae thick, with thin tips; oval amphideal fovea located posterior to buccal cavity; males possessing midventral row of 10–12 papilliform pharyngeal supplements and 13–15 unequal papilliform precloacal supplements; spicules almost straight, 0.85–1.0 cloacal body diameter long; gubernaculum rod-shaped. The main difference between the described species and other known species within the genus is that precloacal supplements are unequal, 6–7 posterior supplements smaller and closer, the rest 7–8 proximal supplements larger and far away. The genus Halanonchus is the first record from the Chinese sea area. The second new species, Micoletzkyia oxycephalata sp. nov. is characterized by very sharp-pointed anterior part of body, paired spicules unequal and precloacal supplement situated anterior to proximal end of spicules. This new species can be easily distinguished from all other known species of Micoletzkyia by outstanding body shape, unequal spicules, stick shaped gubernaculum without apophysis, and the position of precloacal supplement. The third new species, Wieseria zhangi sp. nov. is characterized by slender body with a clavate tail; large amphideal fovea oblong, double contour with a manubrium basally, situated posterior to cephalic setae; spicules short, slightly arcuated, not cephalated proximally, without internal stripe and ventral alae; gubernaculum rodlike, without apophysis; a short midventral spine positioned 11–12 µm anterior to the cloaca. Updated keys to species of three genera Halanonchus, Micoletzkyia, and Wieseria are also given.

Harmful algal blooms (HABs) of dinoflagellates pose significant threats to aquaculture, marine ecosystems, and human health. While resting cysts have been well known for their vital roles in initiating HABs of dinoflagellates, mapping results of the cyst abundance and distribution in marine sediments have been also well documented to be a highly valuable predictor, and thus can be used as a basis to assess the risk of HABs. We attempted to establish a framework for the risk assessment of dinoflagellate HABs based mainly on cyst-mapping of marine sediments and a case application of it to the risk assessment of HABs in the Yellow Sea. In the framework, firstly, the targeted marine area subjected to the assessment was determined and gridded into different assessment units according to their geography, administration, and ecological or economic function. Secondly, the dinoflagellate cyst abundance from the surface sediment, HABs records, and the monitoring results of vegetative cells for all or particular species of concern were collected experimentally or by literature search, as three main indicators scored and weighted respectively with different values. The scoring and weighting process was based on scientific reasoning and empirical consideration as detailed in the text. Thirdly, the risk of HABs occurrences for all or any particular species of concern at each site was ranked with five levels according to the calculated risk values. Finally, the final evaluation results were presented with tables, matrix diagrams, and color-coded textual annotations on nautical charts. As a case application, we performed a risk assessment for HABs of target species in the Yellow Sea, which warned high risks of HABs for Karlodinium veneficum, Gymnodinium catenatum, and others. This assessment framework provides a practical and testable tool for all involved stakeholders, and subject to improvement along with the advancement of ecology of HABs.

To assess the population development of submerged plant species in disturbed lake ecosystems, we need to better understand the genetic diversity and spatial genetic structure at a fine scale, as well as the impact of disturbances on the populations. Caohai Lake, in southwest China, is a suitable natural sampling lake because of its abundance of submerged plants and the intense human disturbance. Three widely distributed species, Potamogeton lucens, Ceratophyllum demersum, and Myriophyllum spicatum, were sampled; the spatial position of each individual was recorded in two-dimensional coordinates; and the species were analyzed genetically using microsatellite markers. Among the species studied, M. spicatum exhibited the highest genetic and clonal diversities. All P. lucens subpopulations but one showed a significant fine-scale spatial genetic structure (FSGS), which may result from the limited gene dispersal. However, M. spicatum and C. demersum, with a relatively large distance of gene dispersal, had no significant FSGS. The FSGS pattern of P. lucens at the dock site with intense boat disturbance was significantly different from that at other sites. Our results imply that the FSGS of submerged plants is affected by many factors including seed dispersal, vegetative reproduction and disturbance from birds and boats. Most subpopulations of the three species had σ scx 2 /σ veg 2 values greater than one, implying that the sexual dispersal contributes more than vegetative dispersal to total gene dispersal. Therefore, it is worth paying attention to the importance of seed dispersal for population development of submerged plants in lake ecosystems.

Global warming has severe effects on cold-water habitats. The Yellow Sea Cold Water Mass (YSCWM) is a typical cold-water habitat in the western Pacific Ocean. The southern YSCWM face much more environmental pressure than the northern YSCWM. We hypothesize that the cold-water Ophiuroid species Ophiura sarsii vadicola, the dominant benthic species in the YSCWM, will be less abundant with an ageing population in the northern YSCWM. Based on a survey in 2018, we found the density of O. sarsii vadicola reached 315 inds./m2 in the northern Yellow Sea, higher than previous records. Biomass and organic mass peaked at 45.5 g/m2 and 4.89 g/m2. There was a strong linear relationship between wet weight and dry weight/ash-free dry weight (AFDW). Over 48 000 individuals were measured (diameter: 1.0–17.5 mm) and were notably smaller than related species from higher latitudes. A Gompertz growth model was established by examining ossicle growth bands. Age structures differed between the northern and southern YSCWM, and the former was dominated by younger individuals. This study enriched our understanding on the ecology of brittle star and provides valuable data and insights for future research on the benthic ecosystems of the Yellow Sea.

Decades of species composition changes can lead to the eutrophication-driven loss of submerged macrophytes in shallow lakes. Investigating the mechanisms of these nature- and human-driven changes is crucial for the restoration and management of such lakes. To investigate the changes in aquatic macrophyte communities over the past two centuries, we analyzed macrofossils in sediments from a 210Pb-dated core obtained in Dongping Lake in the lower Huanghe (Yellow) River Basin, eastern China. Multiple factor analysis (MFA) revealed an association between macrophyte shifts and changes in various environmental stressors (invertebrates, grain size, geochemistry, and documented records), indicating that macrophyte community changes before 1960 were predominately driven by flood disturbances. Ever since, anthropogenic pollution and the construction of water conservancy projects have caused variations in hydrology and nutrients, leading to significant changes in the composition of macrophyte communities. Macrofossil data reveal a decline in diversity and pollution-intolerant species during the late 1980s and the early 2000s, which is indicative of eutrophication. We also found that the current environment of Dongping Lake exhibits a clear degeneration in emergent plants and a proliferation of macrophyte species associated with eutrophic conditions, which could be attributed to water level fluctuation and nutrient input due to the water supply from the eastern route of the South-to-North Water Diversion Project as well as climate warming. Our results provide valuable insights for assessing ecosystem health and the restoration and management of Dongping Lake and similar lakes in the Huanghe River region and elsewhere.

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 °C) 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.

A massive amount of plastic waste has presented an immense management challenge. This escalating ecological damage, coupled with the detrimental effects of plastics infiltrating the marine food web, poses a significant threat to human livelihoods. To combat this, there is a call for the development of plastic detection algorithms using remote sensing data. Here we tested a new index, referred to indexMP, to detect clusters of floating macro plastics in the ocean using satellite imagery. The indexMP was applied to convolution high-pass filtered (3×3) Sentinel 2 Level 1C images, showing the potential to reduce atmospheric interference and enhance the object edges, thereby improving the clarity of detection. In the analysis, we used three scatter plots to identify and assess plastic pixels. To differentiate the common features of plastic from non-plastic objects, the Sentinel 2 bands 5, 8, and 9 were plotted against indexMP calculated and convolution high-pass filtered Level 1C (CHPIC) images. The plastic pixels, clustering in the three scatter plots, showed positive ‘X’, i.e., CHPIC image value and ‘Y’, i.e., each band 5, 8, and 9 reflectance values, along with a CHPIC image value exceeding 0.05. Using the indexMP and scatter plot analysis, we identified plastic pixels containing 14% or more plastic bottles. Detection of other types of plastics, such as fishing nets and plastic bags, required pixel proportions greater than 50%. Hence, plastic bottles were notably responsive even at a low pixel fraction. We further explored the classification of plastic and non-plastic objects by analyzing reed (plant) pixels; the differentiation between plastic and reed was conducted in the band 5 and 9 scatter plots.

FOXL2 and CYP19B are crucial transcription factors in vertebrates and invertebrates that play pivotal roles in sex differentiation and gonadal development. The potential roles of the foxl2 and cyp19b genes in sex determination and gonadal development in Cyprinus carpio var. koi were explored using a non-invasive RNA interference (RNAi) method, histopathological observation and qPCR. Results demonstrate that foxl2 exhibited a sexually dimorphic expression pattern in gonads, with a notable expression in ovaries; cyp19b was expressed in all peripheral tissues, with a particularly prominent expression in brain and gonads. The knockdown of foxl2 by RNAi resulted in delay in the development of the female gonads. Conversely, no notable alterations were discerned in the gonads of C. carpio var. koi following the knockdown of cyp19b. The upregulation of sox9a, amh, and cyp19b following foxl2 knockdown indicates that foxl2 may play a pivotal role in gonadal development. Nevertheless, further investigation is required to ascertain the potential role of cyp19b. This study elucidated the role of foxl2 and enhanced the understanding of the mechanisms of sex determination and gonadal development in C. carpio var. koi.