Surface seawater temperature varies seasonally across latitudes, shaping the temporal organization of plankton communities. However, the phenology of microzooplankton at the community level remains poorly understood, largely due to insufficient temporal resolution in most monitoring programs. In this study, we conducted a high-frequency (three times per week) year-round survey of tintinnids in Qingdao coastal waters, a site characterized by one of the largest annual temperature ranges among global coastal systems. Thirty tintinnid species were identified, and all were neritic taxa. Based on their annual occurrence patterns, the community was classified into four phenological types: cold-water type, temperate type I, temperate type II, and warm-water type, each exhibiting distinct seasonal peaks and thermal performance ranges. These four phenological types constitute the community-level phenological pattern of tintinnids in Qingdao coastal waters. The effective breadths of thermal performance range for each type were 5-8 degrees C, and the number of phenological types increased with the site's annual temperature range, from two in Hong Kong to three in Ningbo and four in Qingdao. Cold-associated types exhibited positively skewed thermal performance curves, indicating higher sensitivity to temperature fluctuations at low temperatures, whereas warm-associated types followed the typical negatively skewed pattern. By linking phenological types to distinct thermal niches, this study provides a framework for understanding how local thermal regimes structure microzooplankton community-level phenology and seasonal succession.

Although relationships between temperature and size are widely discussed in aquatic protists, empirical evidence remains absent for loricate protists, and systematic variations in thermal responses among ecological groups remain unexplored. Using tintinnids as a model system for marine plankton, we present the first comprehensive analysis of temperature-size relationships in loricate protists based on a 72-year dataset (1947–2019) from Jiaozhou Bay. Analysis of 702 microscopic measurements from five tintinnid species revealed fundamentally divergent thermal responses across lorica types. Agglutinated forms demonstrated significant inverse temperature-size relationships (p < 0.001), whereas hyaline forms exhibited positive thermal correlations (p < 0.001). Generalized Additive Models (GAMs) quantified these contrasting responses: entirely agglutinated species experienced 7.61

Abstract Phytoplankton community composition plays a key role in oceanic productivity and in the biological carbon pump. A few in situ surveys documented the structuring role of fine-scale physical structures (1-100 km, day-weeks), such as fronts, on phytoplankton communities. These studies were primarily conducted in highly productive and dynamic regions rather than in oligotrophic and moderate energy conditions commonly found in the global ocean, partly due to challenges in tracking and sampling weaker fronts at high-resolution. Guided by novel SWOT (Surface Water Ocean Topography) altimetry, we used an adaptive and multidisciplinary strategy to conduct high-resolution sampling of a fine-scale front in the oligotrophic Mediterranean Sea. An unprecedented 24-hour continuous sampling within the front was crucial to unveiling a distinct frontal community, where the relative contribution of non-dominant phytoplankton groups increased relative to adjacent water masses. Our results statistically demonstrate that fine-scale features can enhance phytoplankton heterogeneity and community diversity in oligotrophic, moderately energetic regions.

Tintinnids play a key role in marine microbial food webs and are broadly categorized into neritic and oceanic species. While tintinnids have been well studied in the western subarctic gyre of the North Pacific, their occurrence in the eastern subarctic gyre, particularly in the Gulf of Alaska, remains poorly understood. To address this, we investigated the tintinnid community within Prince William Sound and along the Seward Line in the Northern Gulf of Alaska during 12-19 September 2024. Our findings revealed the spatial patterns of neritic and oceanic tintinnid species in this zone. Compared with the western subarctic gyre, oceanic tintinnids in the Northern Gulf of Alaska showed similar dominant oceanic species, suggesting a shared species pool. Twelve common species exhibited specific horizontal and vertical preferences. Different dominant species were found at two nearshore stations: neritic Stenosemella sp. dominated at GAK-1, while oceanic Acanthostomella norvegica was more abundant at PWS-2. Cross-shelf variation in lorica oral diameter correlated inversely with Chl a, reflecting links between morphology and productivity. The occurrence of warm-water Dictyocysta sp. at similar to 57.8 degrees N indicated the possible influence of subtropical water. These findings could serve as baseline data for the eastern subarctic gyre in the context of global change monitoring.

Anthropogenic activities are driving elevated N:P ratios in coastal waters and climate change. However, the ecological stability of plankton ecosystems under these combined stressors remains poorly understood. Using 32-day mesocosm experiments, we evaluated how subtropical plankton ecosystems respond to elevated N:P ratios (40:1) under present (20°C, 440 ppm CO2) and future (23°C, 1000 ppm CO2) scenarios in the first half period, followed by the next half period of restoration to Redfield ratio (16:1). A control group maintained a N:P ratio of 16:1 throughout the experiment. Elevated N:P stimulated phytoplankton biomass and primary productivity, with more pronounced effects observed under the future climate scenario. After 5-day nutrient restructuring, phytoplankton biomass and primary productivity returned to the control levels. However, a rapid rebound was detected after day 23, particularly under the future scenario. Relative to the present scenario, ecological stability (resistance, resilience, and recovery) of phytoplankton biomass and primary productivity declined in the future scenario. Furthermore, nutrient restructuring led to a marked shift from diatom- to dinoflagellate and chlorophyte-dominated assemblages, which was more significant in the future scenario. Elevated N:P ratios also enhanced grazing rates of zooplankton, with stronger effects in the future scenario, though grazing rates returned to control levels following nutrient restoration. Elevated N:P did not affect elemental stoichiometry immediately but enhanced POC:POP and PON:POP by the end of the experiment, particularly in the future scenario. Our findings highlight that mitigating nitrogen inputs alone may be insufficient to restore coastal ecosystems; climate change would increase the challenges of coastal restoration due to nutrient restructuring.

Tintinnid ciliates are suggested as model in plankton ecology and are traditionally identified based on lorica traits with ecological importance (e.g., growth rate, prey selection, and energy transfer efficiency). However, statistical validation has been limited for this taxonomic system, which has been increasingly critiqued. Here, we compiled a global dataset of tintinnid lorica morphology from the literature and statistically tested the validity of lorica traits for classification at family and genus levels. A total of 840 species were selected from over 1 000 documented species, and their distinctive lorica traits (lorica types, open ends, collar presence, and biogeographic distribution patterns) were extracted and linked to the established phylogenetic tree. Significant differences were revealed across family- and genus-level (but not at species-level) classifications and across multiple morphological parameters, including critically distinctive lorica traits, size metrics (lorica oral diameter, LOD, and equivalent spherical diameter, ESD), and individual carbon biomass. Our findings provide quantitative evidence for the validity of morphological taxonomy, and preliminary foundation for linking morphological taxonomy with molecular data. Moreover, our findings provide one of the first statistical foundations for future studies integrating morphology and ecology to elucidate plankton ecological functioning at a global scale.

Microbial food webs (MFWs) constitute the foundational framework of marine pelagic ecosystems, yet their community structure, trophic interactions, and associated abiotic driving factors remain inadequately characterized in the Arctic Ocean. To fill this gap, we conducted a comprehensive ship-based survey during summer 2020 to investigate three MFW trophic levels (picoplankton-Pico, nanoplankton-Nano, microzooplankton-Micro) from surface to 500 m layers. Each MFW component displayed a consistent subsurface peak in its vertical distribution. Additionally, five distinct water masses were identified, and each harboring a distinctive MFW composition. Within this framework, heterotrophic prokaryotes dominated numerically across all water masses, and Pacific-origin Synechococcus emerged as a valuable bioindicator for tracking Arctic environmental fluctuations. Notably, trophic-level abundance ratios conformed to a pyramidal structure, spanning five and two orders of magnitude for Pico:Micro (3.5-12.8 x 105:1) and Nano:Micro (1.6-10.0 x 102:1), respectively. Unlike biomass ratios, for which spanned one and zero order in Pico:Micro (0.4-1.2 x 101:1) and Nano:Micro (0.8-2.6:1), respectively. Concerning biotic-abiotic interactions, both abundance and biomass of each MFW component demonstrated a linear increase with both temperature and Chl a concentrations in Pacific Summer Water. Therein, picoeukaryotes exhibited the steepest slope revealed that their heightened sensitivity to temperature changes. Furthermore, the driving factors for MFW trophic linkages varied significantly among water masses, and the bottom-up control (resource availability) predominating microzooplankton composition. This study upon trophic-level interaction establishes a baseline for quantifying and predicting how future environmental changes may affect pelagic MFWs in polar marine ecosystems.

Marine Group II (MGII) archaea are globally distributed in oceanic waters, yet their ecological functions and metabolic potentials remain elusive due to the lack of pure culture. Here, we investigate the diversity, distribution, and metabolic potential of MGII archaea in the Eastern Indian Ocean using high-throughput sequencing and metagenomic analyses. We identified 37 MGII operational taxonomic units(OTUs), with surface and deep chlorophyll maximum (DCM) layers dominated by clade O1, O3, and P, and deeper waters by O4 and H, reflecting depth-specific ecological niches shaped by environmental gradients. Metagenomic reconstruction yielded 29 archaeal metagenome-assembled genomes (MAGs), including two novel MGII genomes within the Poseidoniaceae and Thalassarchaeaceae families. Metagenomic analysis further revealed previously uncharacterized pathways in MGII, including heterotrophic inorganic carbon fixation via anaplerotic pathways. Notably, the clade N1, prevalent in the DCM, shows strong potential for inorganic carbon assimilation, implicating MGII archaea in the microbial carbon pump and CO2 sequestration. Our results underscore the critical, yet underappreciated, role of MGII archaea in marine biogeochemical cycles and global carbon sink, emphasizing their contribution to CO2 sequestration in oligotrophic marine environments.

Marine virioplankton, the most abundant biological entities in the ocean, play essential roles in microbial ecology and biogeochemical cycling. This study investigates their biogeography in the Northwest Pacific using enhanced-resolution flow cytometry and phenotypic diversity analyses. By resolving four consistent viral subclusters across oceanic and coastal waters and detecting a fifth subcluster in the Yellow Sea, we revealed previously unrecognized patterns of viral community structures. Viral abundances ranged from 3.69 × 10⁶ to 17.09 × 10⁶ particles/mL, showing clear coastal-oceanic differentiation. Environmental gradients, particularly temperature, chlorophyll, and picoplankton abundance, emerged as the primary drivers of virioplankton community structure. These findings underscored the tight coupling between viral populations and their microbial hosts across contrasting marine environments. Phenotypic diversity analysis revealed distinct viral communities in the Luzon Strait, despite comparable abundance patterns to adjacent regions, demonstrating the method's sensitivity in detecting subtle community shifts. This study advances understanding of marine viral biogeography and introduces a robust framework for investigating viral community dynamics. The approach enables high-throughput screening across large spatial scales while maintaining sensitivity to fine-scale community variations, offering new possibilities for monitoring viral responses to environmental change in marine ecosystems.

Tintinnids are key components of the marine microbial food web. Previous studies classified the global biogeography of oceanic tintinnids into three broad Regions at the genus level, but a finer resolution is needed to improve both taxonomic and spatial understanding, especially when compared with the well-established nine-belt framework of epipelagic plankton. Drawing on recent advances in studies of cross-water mass distributions over the past decade, this review refines the biogeography of oceanic tintinnid at the species level. We propose that oceanic tintinnids can be delineated into fourteen biogeographical belts: the Arctic Belt, the Subarctic-Arctic Transition Belt, the Subarctic Belt, two Tropical Submergence Belts, two Subtropical Belts, two Subsurface Maximum Belts, the Equatorial Belt, the Subantarctic Belt, the Subantarctic-Antarctic Transition Belt, the Antarctic Belt and the Antarctic Slope Belt. Each belt had a variable number of endemic species. Oceanic tintinnid biogeography comprised more belts than that of other plankton, with the presence of a Northern-Southern Hemisphere asymmetry. Oceanic tintinnid abundances in different belts had characteristic vertical distributions. More field surveys are needed in future studies to fill the existing knowledge gaps in tintinnid biogeography such as differences between Pacific, Atlantic and Indian Oceans, seasonal variations, poleward expansions.

Estuarine environment exhibited a marked salinity gradient, with zooplankton species displaying varying salinity tolerances. This led to significant spatial distribution differences and the formation of distinct assemblages across salinity gradient. However, research on the transition of zooplankton assemblages from low to high salinity in the Pearl River estuary was limited. Our study aimed to determine whether the patterns of zooplankton community variation in this region can be classified as ecotone or ecocline. Division of zooplankton community along salinity gradient in the Pearl River Estuary were investigated in spring (1-6 April 2023) and summer (1-9 August 2023). A total of 42 and 34 zooplankton species were identified during spring and summer, respectively. Cluster analysis indicated that the zooplankton can be divided into four assemblages along salinity gradient in both seasons. The spatial distribution of dominant species among different assemblages exhibits significant differences. Additionally, there were different representative species of each assemblage and the representative species of different salinity ranges transitioned gradually. The changes of these four zooplankton assemblages from low-salinity to high-salinity waters exhibited a gradual and alternating transition. This did not align with the abrupt change characteristic of the ecotone model, but it was consistent with the gradual alterations associated with the ecocline concept. Therefore, we concluded that the variation pattern of zooplankton communities in the Pearl River estuary aligned more closely with ecocline.

Abstract Although the productivity–biodiversity relationship (PBR) has been a hot topic, few studies have considered how anthropogenic pressures affect PBRs in marine microzooplankton. Here, we provide the first insights into PBRs in tintinnid assemblages using 18‐yr data from Jiaozhou Bay, a typical coastal bay in the Yellow Sea. We hypothesized and verified that PBRs vary across contrasting anthropogenic nutrient inputs and that functional and phylogenetic diversity would deliver more information than conventional species richness. High productivity promotes more diversity under low to medium rather than high anthropogenic nutrient inputs. Compared to species richness, functional and phylogenetic diversity reveal more PBR patterns and respond more quickly in response to varying anthropogenic inputs. A concave+ PBR is revealed for functional diversity in the ecozone with highly active water exchange. Our study contributes to the understanding of PBR in marine unicellular secondary producers and their responses to anthropogenic nutrient inputs in coastal ecosystems.

The community structure of microzooplanktonic ciliates – encompassing size spectrum, biodiversity and biotic–abiotic interplay – is critical for unravelling their ecological role in marine ecosystems, yet it remains challenging to elucidate on a global scale. To address this knowledge gap, we conducted field observational studies across five temperature zones (North Frigid Zone, NFZ; Sub-Arctic Zone, SAZ; North Temperate Zone, NTZ; Torrid Zone, TZ; South Frigid Zone, SFZ). Our analysis demonstrates a sharp decline in ciliate abundance and biomass below the 100 m layer, with distinct vertical distribution patterns observed in each climate region. Moreover, although abundance of ciliate size spectra exhibited a decrease trend from small to large size spectra globally, there were steeper slope lines observed in both polar zones (NFZ and SFZ) compared to the other temperature zones. Latitudinally, ciliate abundance and tintinnid biodiversity exhibited an anti-phase relationship, where the TZ hosted peak biodiversity, while the polar seas showed the highest abundance. Furthermore, a multivariate biota–environment analysis indicated that temperature has a primary influence on ciliate community constitution in the global marine ecosystem, and the bottom-up control plays a key role in shaping assemblages. In conclusion, these results underscore the unprecedented divergences in ciliate trait structure among five temperature zones and can be taken as a guideline for assessing the potential effects of climate change on pelagic ciliates in future marine realms.

Synechococcus is abundant and globally widespread in various marine environments. Seasonal and spatial variations in Synechococcus abundance, pigment types, and genetic diversity were investigated based on flow cytometric analysis and high-throughput sequencing of cpcBA operon (encoding phycocyanin) and rpoC1 gene (encoding RNA polymerase) in a temperate semi-enclosed bay. Synechococcus abundance exhibited seasonal variations with the highest value in summer and the lowest value in winter, which was consistent with temperature variation. Three pigment types of Synechococcus type 1, type 2, and type 3 were distinguished based on cpcBA operon, which displayed obvious variations spatially between the inner and the outer bay. Freshwater discharge and water turbidity played important roles in regulating Synechococcus pigment types. Synechococcus assemblages were phylogenetically diverse (12 different lineages) based on rpoC1 gene and dominated by three core lineages S5.1-I, S5.1-IX, and S5.2-CB5 in different seasons. Our study demonstrated that Synechococcus abundance, pigment types, and genetic diversity displayed variations seasonally and spatially by different techniques, which were mainly driven by temperature, salinity, nutrients, and turbidity. The combination of more technical means provides more information for studying Synechococcus distribution. In this study, three pigment types of Synechococcus were discriminated simultaneously by dual lasers flow cytometer for the first time.

OBJECTIVES:Porphyromonas gingivalis (P. gingivalis) is a keystone periodontal pathogen associated with various gastro-intestinal tract cancers. However, whether P. gingivalis can promote oral squamous cell carcinoma (OSCC) and the underlying mechanism associated with such promotion remain unclear. MATERIALS AND METHODS:In this study, OSCC xenograft models were used to evaluate the effects of P. gingivalis on tumor progression. The functional studies were done on several OSCC cell lines in vitro. P. gingivalis-specific 16S rRNA fluorescent in situ hybridization (FISH) was used to test its prevalence in clinical samples. RESULTS:We found that P. gingivalis increased tumor volume and tumor growth in OSCC nude models. Functional studies demonstrated that P. gingivalis inhibited the apoptosis of OSCC cells by promoting cellular autophagy. P. gingivalis was more prevalent in FISH samples from patients with OSCC than from patients with leukoplakia or healthy subjects (70% vs. 47.2% vs. 33.3%, p = 0.045 and p < 0.001, respectively). CONCLUSION:These data suggest that P. gingivalis plays an accelerating role in OSCC progression and contributes to OSCC by enhancing the autophagy pathway to reduce carcinoma apoptosis.

Dysregulated Epiregulin (EREG) can activate epidermal growth factor receptor (EGFR) and promote tumor progression in head and neck squamous cell carcinoma (HNSCC). However, the mechanisms underlying EREG dysregulation remain largely unknown. Here, we showed that dysregulated EREG was highly associated with enhanced PDL1 in HNSCC tissues. Treatment of HNSCC cells with EREG resulted in upregulated PDL1 via the c-myc pathway. Of note, we found that N-glycosylation of EREG was essential for its stability, membrane location, biological function, and upregulation of its downstream target PDL1 in HNSCC. EREG was glycosylated at N47 via STT3B glycosyltransferases, whereas mutations at N47 site abrogated N-glycosylation and destabilized EREG. Consistently, knockdown of STT3B suppressed glycosylated EREG and inhibited PDL1 in HNSCC cells. Moreover, treatment of HNSCC cells with NGI-1, an inhibitor of STT3B, blocked STT3B-mediated glycosylation of EREG, leading to its degradation and suppression of PDL1. Finally, combination of NGI-1 treatment with anti-PDLl therapy synergistically enhanced the efficacy of immunotherapy of HNSCC in vivo. Taken together, STT3B-mediated N-glycosylation is essential for stabilization of EREG, which mediates PDL1 upregulation and immune evasion in HNSCC.

Blockchain, as a distributed ledger technology is a decentralised, transparent and traceable technology. It has rapidly developed during the last decade and is widely used in many industries such as the oil and gas engineering. This study first describes the development, classification, characteristics and key technologies of the blockchain technology. Then, the application of blockchain and the challenges currently encountered during its implementation in the oil and gas industry are summarised. Finally, some feasible solutions are presented to overcome these challenges. The current work provides a deep insight of the main research progress of the application of blockchain technology in the oil and gas industry and is expected to enable the further development of this sector. [Received: May 18, 2023; Accepted: December 12, 2023]

Neuston, situated at the air-sea interface, stands as a crucial frontier in the realm of the global warming. Despite its unique habitat, there remains a need to substantiate the composition, diel dynamic and biotic-abiotic interaction of neustonic zooplankton in the tropical seas. In this study, we present rare observational data on neustonic zooplankton (0–20 cm) in the oligotrophic tropical South China Sea (SCS) during the summer of 2022. A total of eighteen samples were collected and analyzed, revealing the presence of fourteen taxa from eight phyla. The most prevalent group was Cypridina, accounting for 33.7% of the total abundance, followed by copepods (29.0%) and jellyfish (10.9%). Within copepods, the genus Pontella exhibited the highest relative abundance (38.0%). Additionally, each neuston taxon displayed unique diel distribution patterns. Cypridina was the most abundant taxon during the night (40.4%), while it shifted to copepod dominance during the day (50.4%). Among copepods, genus Pontella and larvae were dominant groups at night (44.7%) and during the day (30.0%), respectively. Moreover, a multivariate biota-environment analysis demonstrated that temperature, pH, dissolved oxygen and Si(OH)4 significantly impacted neuston composition. Notably, both jellyfish and sea snails showed a significant positive correlation with temperature, suggesting their potential dominance in the neuston community in response to future global warming in the oligotrophic tropical seas. This study lays a robust foundation for recognizing the neuston community in the oceanic SCS, and helps evaluate the long-term risks to neuston habitats under climate changes.