Quantum-Confined-Superfluidics-Enabled Multiresponsive MXene-Based Actuators.

MXene, renowned for its natural "quantum-confined-superfluidic" (QSF) channels, demonstrates superior electrical/thermal conductivity, favorable hydrophilicity, and remarkable mechanical strength, rendering it an ideal candidate for multiresponsive actuators, which are promising for soft electronics and robots. Currently, most MXene-based actuators are mainly prepared by combining an active layer and an inner layer, with only a few utilizing regulated QSF channels. However, tailoring QSF channels for multiresponsive actuators is extremely challenging. Herein, we introduce a multiresponsive graphene oxide (GO)&Fe3O4/MXene actuator that can respond to humidity, light, heat, electricity, and magnetic fields by constructing asymmetric QSF channels. The asymmetric water adsorption, transportation, and desorption behaviors, controlled by the different QSF channels between the GO&Fe3O4 layer and the MXene layer, enable the multiresponsiveness of the actuator. As proof-of-concept demonstrations, several smart devices, such as a bionic crab-like crawler, a transporting flower robot, and a smart gripper, are prepared, holding great potential for advancing future soft robotics.

Distinct patterns of distribution, community assembly and cross-domain co-occurrence of planktonic archaea in four major estuaries of China.

BACKGROUND: Archaea are key mediators of estuarine biogeochemical cycles, but comprehensive studies comparing archaeal communities among multiple estuaries with unified experimental protocols during the same sampling periods are scarce. Here, we investigated the distribution, community assembly, and cross-domain microbial co-occurrence of archaea in surface waters across four major estuaries (Yellow River, Yangtze River, Qiantang River, and Pearl River) of China cross climatic zones (~ 1,800 km) during the winter and summer cruises. RESULTS: The relative abundance of archaea in the prokaryotic community and archaeal community composition varied with estuaries, seasons, and stations (reflecting local environmental changes such as salinity). Archaeal communities in four estuaries were overall predominated by ammonia-oxidizing archaea (AOA) (aka. Marine Group (MG) I; primarily Nitrosopumilus), while the genus Poseidonia of Poseidoniales (aka. MGII) was occasionally predominant in Pearl River estuary. The cross-estuary dispersal of archaea was largely limited and the assembly mechanism of archaea varied with estuaries in the winter cruise, while selection governed archaeal assembly in all estuaries in the summer cruise. Although the majority of archaea taxa in microbial networks were peripherals and/or connectors, extensive and distinct cross-domain associations of archaea with bacteria were found across the estuaries, with AOA as the most crucial archaeal group. Furthermore, the expanded associations of MGII taxa with heterotrophic bacteria were observed, speculatively indicating the endogenous demand for co-processing high amount and diversity of organic matters in the estuarine ecosystem highly impacted by terrestrial/anthropogenic input, which is worthy of further study. CONCLUSIONS: Our results highlight the lack of common patterns in the dynamics of estuarine archaeal communities along the geographic gradient, expanding the understanding of roles of archaea in microbial networks of this highly dynamic ecosystem.

Gut bacterial consortium enriched in a biofloc system protects shrimp against Vibrio parahaemolyticus infection.

BACKGROUND: Shrimp cultured in a biofloc system (BFS) have a lower disease incidence than those farmed in a water exchange system (WES). Although a number of studies have reported that the gut bacterial community induced by BFS is highly associated with shrimp disease resistance, the causal relationship remains unknown. Here, the promotive roles of gut bacterial community induced by BFS in pathogenic Vibrio infection resistance and its potential micro-ecological and physiological mechanisms were investigated by gut bacterial consortium transplantation and synthetic community (SynCom) construction. RESULTS: The BFS induced a more stable and resistant gut bacterial community, and significantly enriched some beneficial bacterial taxa, such as Paracoccus, Ruegeria, Microbacterium, Demequina, and Tenacibaculum. Transplantation of a gut bacterial consortium from BFS shrimp (EnrichBFS) greatly enhanced the stability of the bacterial community and resistance against pathogenic V. parahaemolyticus infection in WES shrimp, while transplantation of a gut bacterial consortium from WES shrimp significantly disrupted the bacterial community and increased pathogen susceptibility in both WES and BFS shrimp. The addition of EnrichBFS in shrimp postlarvae also improved the pathogen resistance through increasing the relative abundances of beneficial bacterial taxa and stability of bacterial community. The corresponding strains of five beneficial bacterial taxa enriched in BFS shrimp were isolated to construct a SynComBFS. The addition of SynComBFS could not only suppress disease development, but also improve shrimp growth, boost the digestive and immune activities, and restore health in diseased shrimp. Furthermore, the strains of SynComBFS well colonized shrimp gut to maintain a high stability of bacterial community. CONCLUSIONS: Our study reveals an important role for native microbiota in protecting shrimp from bacterial pathogens and provides a micro-ecological regulation strategy towards the development of probiotics to ameliorate aquatic animal diseases. Video Abstract.

Assessing the efficacy of bleaching powder in disinfecting marine water: Insights from the rapid recovery of microbiomes.

Single-bleaching powder disinfection is a highly prevalent practice to disinfect source water for marine aquaculture to prevent diseases. However, due to the decay of active chlorine and the presence of disinfectant resistance bacteria (DRB), the effects of bleaching powder on prokaryotic community compositions (PCCs) and function in marine water remain unknown. In the present study, the source water in a canvas pond was treated with the normal dose of bleaching powder, and the impact on PCCs and functional profiles was investigated using 16S rRNA gene amplicon sequencing. The bleaching powder strongly altered the PCCs within 0.5 h, but they began to recover at 16 h, eventually achieving 76% similarity with the initial time at 72 h. This extremely rapid recovery was primarily driven by the decay of Bacillus and the regrowth of Pseudoalteromonas, both of which are DRB. Abundant community not only help PCCs recover but also provide larger functional redundancy than rare community. During the recovery of PCCs, stochastic processes drove the community assembly. After 72 h, five out of seven identified disinfectant resistance genes related to efflux pump systems were highly enriched, primarily in Staphylococcus and Bacillus. However, 15 out of the 16 identified antibiotic resistance genes (ARGs) remained unchanged compared to the initial time, indicating that bleaching powder does not contribute to ARGs removal. Overall, the findings demonstrate that single-bleaching powder disinfection cannot successfully meet the objective of disease prevention in marine aquaculture water due to the extremely rapid recovery of PCCs. Hence, secondary disinfection or novel disinfection strategies should be explored for source water disinfection.

Transcriptional landscape of myasthenia gravis revealed by weighted gene coexpression network analysis.

Background: As one of the most common autoimmune diseases, myasthenia gravis (MG) severely affects the quality of life of patients. Therefore, exploring the role of dysregulated genes between MG and healthy controls in the diagnosis of MG is beneficial to reveal new and promising diagnostic biomarkers and clinical therapeutic targets. Methods: The GSE85452 dataset was downloaded from the Gene Expression Omnibus (GEO) database and differential gene expression analysis was performed on MG and healthy control samples to identify differentially expressed genes (DEGs). The functions and pathways involved in DEGs were also explored by functional enrichment analysis. Significantly associated modular genes were identified by weighted gene co-expression network analysis (WGCNA), and MG dysregulated gene co-expression modular-based diagnostic models were constructed by gene set variance analysis (GSVA) and least absolute shrinkage and selection operator (LASSO). In addition, the effect of model genes on tumor immune infiltrating cells was assessed by CIBERSORT. Finally, the upstream regulators of MG dysregulated gene co-expression module were obtained by Pivot analysis. Results: The green module with high diagnostic performance was identified by GSVA and WGCNA. The LASSO model obtained NAPB, C5orf25 and ERICH1 genes had excellent diagnostic performance for MG. Immune cell infiltration results showed a significant negative correlation between green module scores and infiltration abundance of Macrophages M2 cells. Conclusion: In this study, a diagnostic model based on the co-expression module of MG dysregulated genes was constructed, which has good diagnostic performance and contributes to the diagnosis of MG.

Contrasting Mechanisms Determine the Microeukaryotic and Syndiniales Community Assembly in a Eutrophic bay.

Syndiniales is a diverse parasitic group, increasingly gaining attention owing to its high taxonomic diversity in marine ecosystems and inhibitory effects on the dinoflagellate blooms. However, their seasonal dynamics, host interactions, and mechanisms of community assembly are largely unknown, particularly in eutrophic waters. Here, using 18S rRNA gene amplicon sequencing, we intended to elucidate the interactions between Syndiniales and microeukaryotes, as well as community assembly processes in a eutrophic bay. The results showed that Syndiniales group II was dominating throughout the year, with substantially higher abundance in the winter and spring, whereas Syndiniales group I was more abundant in the summer and autumn. Temperature and Dinoflagellata were the most important abiotic and biotic factors driving variations of the Syndiniales community, respectively. The assembly processes of microeukaryotes and Syndiniales were completely different, with the former being controlled by a balance between homogeneous selection and drift and the latter being solely governed by drift. Network analysis revealed that Syndiniales group II had the largest number of interactions with microeukaryotes, and they primarily associated with Dinoflagellata in the winter, while interactions with Chlorophyta and Bacillariophyta increased dramatically in summer and autumn. These findings provide significant insights in understanding the interactions and assembly processes of Syndiniales throughout the year, which is critical in revealing the roles of single-celled parasites in driving protist dynamics in eutrophic waters.

Metagenomic insights into the functional genes across transects in a typical estuarine marsh.

Salt marshes are potentially one of the most efficient carbon (C) sinks worldwide and perform important ecosystem functions, but sea level rise alters marsh sediments properties and thus threatens microbial roles in ecosystem functioning. Yet, the mechanisms of interactions of biochemical processes with microorganisms and their functions are still not fully understood. Here, this study investigated metagenomic taxonomic and functional profiling from the water-land conjugation up to about 300 m, 1000 m, and 2500 m in three parallel transects, respectively, in Hangzhou Bay, China. The results showed that soil physicochemical factors drove metagenomic taxonomic and functional genes in the 2500-m transect significantly different from other sites. The 2500-m transect had a greater abundance of Chloroflexi and Acidobacteria but lower in Proteobacteria. The metagenomic functional genes related to Phosphorus Metabolism (PHO) and Potassium Metabolism (POT) increased in the 2500 m. Additionally, nutrient-cycling functions and the genera of Anaeromyxobacter, Roseiflexus, and Geobacter related to PHO, POT at 2500 m were significantly greater than those of other transects. Carbon cycling functions within Carbohydrates (CHO) also differed significantly across transects. These research results demonstrated that the relative abundance of metagenomic microorganisms and their functional genes were significantly separated across the three transects. The vegetation type, salinity, and soil properties might be among the influencing factors.

Geographic patterns and determinants of antibiotic resistomes in coastal sediments across complex ecological gradients.

Coastal areas are highly influenced by terrestrial runoffs and anthropogenic disturbances, commonly leading to ecological gradients from bay, nearshore, to offshore areas. Although the occurrence and distribution of sediment antibiotic resistome are explored in various coastal environments, little information is available regarding geographic patterns and determinants of coastal sediment antibiotic resistomes across ecological gradients at the regional scale. Here, using high-throughput quantitative PCR, we investigated the geographic patterns of 285 antibiotic resistance genes (ARGs) in coastal sediments across a ~ 200 km scale in the East China Sea. Sediment bacterial communities and physicochemical properties were characterized to identify the determinants of sediments antibiotic resistome. Higher richness and abundance of ARGs were detected in the bay samples compared with those in nearshore and offshore samples, and significant negative correlations between the richness and/or abundance of ARGs and the distance to coastline (DTC) were identified, whereas different types of ARGs showed inconsistency in their relationships with DTC. The composition of antibiotic resistome showed significant correlations with nutrition-related variables (including NH4 +-N, NO3 --N, and total phosphorus) and metals/metalloid (including As, Cu, Ni, and Zn), suggesting that terrestrial disturbances largely shape the antibiotic resistome. The Bipartite network showed strong associations between ARGs and mobile genetic elements (MGEs), and Partial Least Squares Path Modeling further revealed that terrestrial disturbance strength (as indicated by DTC) directly affected abiotic environmental conditions and bacterial community composition, and indirectly affected antibiotic resistome via MGEs. These findings provide insights into regional variability of sediment antibiotic resistome and its shaping path across complex ecological gradients, highlighting terrestrial disturbances as determinative forces in shaping coastal sediment antibiotic resistomes.

Disentangling the Mechanisms Shaping the Prokaryotic Communities in a Eutrophic Bay.

Eutrophication occurring in coastal bays is prominent in impacting local ecosystem structure and functioning. To understand how coastal bay ecosystem function responds to eutrophication, comprehending the ecological processes associated with microbial community assembly is critical. However, quantifying the contribution of ecological processes to the assembly of prokaryotic communities is still limited in eutrophic waters. Moreover, the influence of these ecological processes on microbial interactions is poorly understood. Here, we examined the assembly processes and co-occurrence patterns of prokaryotic communities in a eutrophic bay using 156 surface seawater samples collected over 12 months. The variation of prokaryotic community compositions (PCCs) could be mainly explained by environmental factors, of which temperature was the most important. Under high environmental heterogeneity conditions in low-temperature seasons, heterogeneous selection was the major assembly process, resulting in high ß-diversity and more tightly connected co-occurrence networks. When environmental heterogeneity decreased in high-temperature seasons, drift took over, leading to decline in ß-diversity and network associations. Microeukaryotes were found to be important biological factors affecting PCCs. Our results first disentangled the contribution of drift and microbial interactions to the large unexplained variation of prokaryotic communities in eutrophic waters. Furthermore, a new conceptual model linking microbial interactions to ecological processes was proposed under different environmental heterogeneity. Overall, our study sheds new light on the relationship between assembly processes and co-occurrence of prokaryotic communities in eutrophic waters. IMPORTANCE A growing number of studies have examined roles of microbial community assembly in modulating community composition. However, the relationships between community assembly and microbial interactions are not fully understood and rarely tested, especially in eutrophic waters. In this study, we built a conceptual model that links seasonal microbial interactions to ecological processes, which has not been reported before. The model showed that heterogeneous selection plays an important role in driving community assembly during low-temperature seasons, resulting in higher ß-diversity and more tightly connected networks. In contrast, drift became a dominant force during high-temperature seasons, leading to declines in the ß-diversity and network associations. This model could function as a new framework to predict how prokaryotic communities respond to intensified eutrophication induced by climate change in coastal environment.

Comparing the Profiles of Raw and Cooked Donkey Meat by Metabonomics and Lipidomics Assessment.

Heat cooking of meat gives it a specific taste and flavor which are favored by many consumers. While the characteristic taste components of chicken, duck, pig, and seafood have been studied, there is a lack of information about the molecular components that give donkey meat its unique taste. Here, the characterization profiles of raw donkey meat (RDM) and cooked donkey meat (CDM) meat by metabonomics and lipidomics. The results showed that a total of 186 metabolites belonging to 8 subclasses were identified in CDM and RDM, including carbohydrates (27.42%), amino acids (17.20%), lipids (13.44%), and nucleotides (9.14%). In total, 37 differential metabolites were identified between CDM and RDM. Among these, maltotriose, L-glutamate, and L-proline might predominantly contribute to the unique umami and sweet taste of donkey meat. Comprehensive biomarker screening detected 9 potential metabolite markers for the discrimination among RDM and CDM, including L-glutamate, gamma-aminobutyric acid, and butane-1, 2, 3, 4-tetrol. Moreover, a total of 992 and 1,022 lipids belonging to 12 subclasses were identified in RDM and CDM, respectively, mainly including triglycerides (TGs) and glycerophospholipids (GPs). Of these lipids, 116 were significantly different between CDM and RDM. The abundances of 61 TGs rich in saturated and monounsaturated fatty acids were retained in CDM, whereas the abundances of 37 GPs rich in polyunsaturated fatty acids were reduced, suggesting that TGs and GPs might be the predominant lipids for binding and generating aroma compounds, respectively. A total of 13 lipids were determined as potential markers for the discrimination among RDM and CDM, including PC(O-16:2/2:0), LPE(22:5/0:0), and PC(P-16:0/2:0). In conclusion, this study provided useful information about the metabolic and lipid profiles of donkey meat which may explain its unique taste and flavor, which could serve as a basis for the development and quality control of donkey meat and its products.

Sucrose addition directionally enhances bacterial community convergence and network stability of the shrimp culture system.

Sucrose is an effective carbon source for creating more reliable and environmentally friendly conditions for shrimp growth by regulating bacteria in biofloc-based culture systems. However, the influence of sucrose addition on the interaction, co-occurrence networks, and assembly mechanisms of bacterial communities in biofloc-based culture systems remains largely unknown. Here, we comprehensively investigated the effects of sucrose addition on bacterial communities in three habitats (water, bioflocs, and gut). The bacterial community structures and compositions of these three habitats became more similar in groups with sucrose addition, compared with those in controls. More than 50% gut bacterial communities were mainly derived from water and biofloc communities in the sucrose addition groups, but only about 33% bacterial communities migrated from water and biofloc to the gut in the control culture system. Sucrose addition accordantly enriched core taxa belonging to the phylum Actinobacteria and the families Rhodobacteraceae and Flavobacteriaceae in water, biofloc, and gut habitats. These core taxa were important for maintaining bacterial network stability in the sucrose addition culture systems and some were identified as keystone taxa for improving shrimp growth. Furthermore, after sucrose addition, gut bacterial community assembly from water and biofloc was dominated by the heterogeneous select with the ratios of 55-91% and 67-83%, respectively, indicating that sucrose addition can directionally shape the bacterial assembly of the shrimp culture system. These results provide a basis for selectively regulating certain beneficial taxa to improve shrimp growth in culture systems.

Characterization of the complete mitochondrial genome of blacktip shark Carcharhinus limbatus (Carcharhiniformes: Carcharhinidae).

In this study, we aimed to determine the complete mitochondrial genome of blacktip shark Carcharhinus limbatus. The mitochondrial genome was 16,705 bp in length, including 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region. Phylogenetic analysis was done using the Bayesian inference method, which showed a close relationship between C. limbatus and C. amblyrhynchoides.

Comparison of body size and reproductive hormones in high- and low-yielding Wulong geese.

Wulong geese are renowned for their egg-laying and reproductive abilities. This work investigated the potential of using body size traits in the selection and breeding of high-yielding Wulong geese. A total of forty 479day-old female geese (high-yielding geese, n = 20; low-yielding geese, n = 20) were selected to evaluate the relationship between body weight, body size trait indicators, serum reproductive hormones, and biochemical indicators. The results showed that serum estradiol (E2), glucose (GLU), and triglyceride (TG) concentrations, together with pubic spacing and abdominal circumference were significantly higher in high-yielding geese (P < 0.01), whereas the opposite was true for neck circumference, neck length, and tibial circumference. In addition, the serum testosterone (T) concentration and body weight were higher in high-yielding geese (P < 0.05). Neck circumference and neck length were negatively correlated with E2 and TG (P < 0.01); while pubic spacing and abdominal circumference were positively correlated with E2, GLU, and TG (P < 0.01), the highest correlation coefficient was 0.777 between TG and pubic spacing; T was also strongly associated with neck circumference (P < 0.01). In conclusion, high-yielding Wulong geese can be selected through neck circumference, neck length, pubic spacing, and abdominal circumference.

Ecological Dynamics and Co-occurrences Among Prokaryotes and Microeukaryotes in a Diatom Bloom Process in Xiangshan Bay, China.

Diatom blooms can significantly affect the succession of microbial communities, yet little is known about the assembly processes and interactions of microbial communities during autumn bloom events. In this study, we investigated the ecological effects of an autumn diatom bloom on prokaryotic communities (PCCs) and microeukaryotic communities (MECs), focusing on their assembly processes and interactions. The PCCs were largely dominated by Alphaproteobacteria, Gammaproteobacteria, Cyanobacteria, and Flavobacteria, while the MECs primarily included Diatomea, Dinoflagellata, and Chlorophyta. The succession of both PCCs and MECs was mainly driven by this diatom bloom and environmental factors, such as nitrate and silicate. Null modeling revealed that homogeneous selection had a more pronounced impact on the structure of PCCs compared with that of MECs. In particular, drift and dispersal limitation cannot be neglected in the assembly processes of MECs. Co-occurrence network analyses showed that Litorimicrobium, Cercozoa, Marine Group I (MGI), Cryptomonadales, Myrionecta, and Micromonas may affect the bloom process. In summary, these results elucidated the complex, robust interactions and obviously distinct assembly mechanisms of PCCs and MECs during a diatom bloom and extend our current comprehension of the ecological mechanisms and microbial interactions involved in an autumn diatom bloom process.

Contrasting patterns of bacterial communities in the rearing water and gut of Penaeus vannamei in response to exogenous glucose addition.

Supplementing exogenous carbon sources is a practical approach to improving shrimp health by manipulating the microbial communities of aquaculture systems. However, little is known about the microbiological processes and mechanisms of these systems. Here, the effects of glucose addition on shrimp growth performance and bacterial communities of the rearing water and the shrimp gut were investigated to address this knowledge gap. The results showed that glucose addition significantly improved the growth and survival of shrimp. Although the α-diversity indices of both bacterioplankton communities and gut microbiota were significantly decreased by adding glucose, both bacterial communities exhibited divergent response patterns to glucose addition. Glucose addition induced a dispersive bacterioplankton community but a more stable gut bacterial community. Bacterial taxa belonging to Ruegeria were significantly enriched by glucose in the guts, especially the operational taxonomic unit 2575 (OTU2575), which showed the highest relative importance to the survival rate and individual weight of shrimp, with the values of 43.8 and 40.6%, respectively. In addition, glucose addition increased the complexity of interspecies interactions within gut bacterial communities and the network nodes from Rhodobacteraceae accounted for higher proportions and linked more with the nodes from other taxa in the glucose addition group than that in control. These findings suggest that glucose addition may provide a more stable gut microbiota for shrimp by increasing the abundance of certain bacterial taxa, such as Ruegeria. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-021-00124-9.

Enterococcus faecium are associated with the modification of gut microbiota and shrimp post-larvae survival.

BACKGROUND: Probiotics are widely used to promote host health. Compared to mammals and terrestrial invertebrates, little is known the role of probiotics in aquatic invertebrates. In this study, eighteen tanks with eight hundred of shrimp post-larvae individuals each were randomly grouped into three groups, one is shrimps administered with E. faecium as probiotic (Tre) and others are shrimps without probiotic-treatment (CK1: blank control, CK2: medium control). We investigated the correlations between a kind of commercial Enterococcus faecium (E. faecium) powder and microbiota composition with function potentials in shrimp post-larvae gut. RESULTS: We sequenced the 16S rRNA gene (V4) of gut samples to assess diversity and composition of the shrimp gut microbiome and used differential abundance and Tax4Fun2 analyses to identify the differences of taxonomy and predicted function between different treatment groups. The ingested probiotic bacteria (E. faecium) were tracked in gut microbiota of Tre and the shrimps here showed the best growth performance especially in survival ratio (SR). The distribution of SR across samples was similar to that in PCoA plot based on Bray-Curits and two subgroups generated (SL: SR < 70%, SH: SR ≥ 70%). The gut microbiota structure and predicted function were correlated with both treatment and SR, and SR was a far more important factor driving taxonomic and functional differences than treatment. Both Tre and SH showed a low and uneven community species and shorted phylogenetic distance. We detected a shift in composition profile at phylum and genus level and further identified ten OTUs as relevant taxa that both closely associated with treatment and SR. The partial least squares path model further supported the important role of relevant taxa related to shrimp survival ratio. CONCLUSIONS: Overall, we found gut microbiota correlated to both shrimp survival and ingested probiotic bacteria (E. faecium). These correlations should not be dismissed without merit and will uncover a promising strategy for developing novel probiotics through certain consortium of gut microbiota.

Assessing the Risks of Potential Bacterial Pathogens Attaching to Different Microplastics during the Summer-Autumn Period in a Mariculture Cage.

As microplastic pollution continues to increase, an emerging threat is the potential for microplastics to act as novel substrates and/or carriers for pathogens. This is of particular concern for aquatic product safety given the growing evidence of microplastic ingestion by aquaculture species. However, the potential risks of pathogens associated with microplastics in mariculture remain poorly understood. Here, an in situ incubation experiment involving three typical microplastics including polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP) was conducted during the summer-autumn period in a mariculture cage. The identification of potential pathogens based on the 16S rRNA gene amplicon sequencing and a custom-made database for pathogenic bacteria involved in aquatic environments, was performed to assess the risks of different microplastics attaching potential pathogens. The enrichment of pathogens was not observed in microplastic-associated communities when compared with free-living and particle-attached communities in surrounding seawater. Despite the lower relative abundance, pathogens showed different preferences for three microplastic substrates, of which PET was the most favored by pathogens, especially potentially pathogenic members of Vibrio, Tenacibaculum, and Escherichia. Moreover, the colonization of these pathogens on microplastics was strongly affected by environmental factors (e.g., temperature, nitrite). Our results provide insights into the ecological risks of microplastics in mariculture industry.

Prokaryotic community succession and assembly on different types of microplastics in a mariculture cage.

Microplastics have emerged as a new anthropogenic substrate that can readily be colonized by microorganisms. Nevertheless, microbial community succession and assembly among different microplastics in nearshore mariculture cages remains poorly understood. Using an in situ incubation experiment, 16S rRNA gene amplicon sequencing, and the neutral model, we investigated the prokaryotic communities attached to polyethylene terephthalate (PET), polyethylene (PE), and polypropylene (PP) in a mariculture cage in Xiangshan Harbor, China. The α-diversities and compositions of microplastic-attached prokaryotic communities were significantly distinct from free-living and small particle-attached communities in the surrounding water but relatively similar to the large particle-attached communities. Although a distinct prokaryotic community was developed on each type of microplastic, the communities on PE and PP more closely resembled each other. Furthermore, the prokaryotic community dissimilarity among all media (microplastics and water fractions) tended to decrease over time. Hydrocarbon-degrading bacteria Alcanivorax preferentially colonized PE, and the genus Vibrio with opportunistically pathogenic members has the potential to colonize PET. Additionally, neutral processes dominated the prokaryotic community assembly on PE and PP, while selection was more responsible for the prokaryotic assembly on PET. The assembly of Planctomycetaceae and Thaumarchaeota Marine Group I taxa on three microplastics were mainly governed by selection and neutral processes, respectively. Our study provides further understanding of microplastic-associated microbial ecology in mariculture environments.

Seasonality in Spatial Turnover of Bacterioplankton Along an Ecological Gradient in the East China Sea: Biogeographic Patterns, Processes and Drivers.

Seasonal succession in bacterioplankton is a common process in marine waters. However, seasonality in their spatial turnover is largely unknown. Here, we investigated spatial turnover of surface bacterioplankton along a nearshore-to-offshore gradient in the East China Sea across four seasons. Although seasonality overwhelmed spatial variability of bacterioplankton composition, we found significant spatial turnover of bacterioplankton along the gradient as well as overall seasonal consistency in biogeographic patterns (including distance-decay relationship and covariation of community composition with distance to shore) with subtle changes. Bacterioplankton assembly was consistently dominated by deterministic mechanisms across seasons, with changes in specific processes. We found overall seasonal consistency in abiotic factors (mainly salinity and nitrogen and phosphorus nutrients) shaping bacterioplankton composition, while phytoplankton showed a similar influence as abiotic factors only in spring. Although key taxa responsible for bacterioplankton spatial turnover showed certain season-specificity, seasonal switching between closely related taxa occurred within most dominant families. Moreover, many close relatives showed different responding patterns to the environmental gradients in different seasons, suggesting their differences in both seasonally climatic and spatially environmental preferences. Our results provide insights into seasonal consistency and variability in spatial turnover of bacterioplankton in terms of biogeographic patterns, ecological processes, and external and internal drivers.