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Optimizing the spatial layout of high-quality tourist attractions is of great significance in the sustainable development of the tourism industry. This work employs the ArcGIS spatial analysis tool to study the form, equality, and density of the spatial distribution of the 892 3A+ tourist attractions (high-quality tourist attractions hereafter) in Shandong Province, China. It also examines the factors influencing the spatial distribution of tourist attractions from the perspectives of geographic features and landscapes, culture and heritage, socioeconomic development, and transportation. We therefore find the following: 1) High-quality tourist attractions in Shandong Province have obvious clustering in spatial distribution with the high-density areas mainly concentrated in Qingdao, Jining, Jinan, Tai'an and other cities. Influenced by resource endowment and economic development, the two major geographical areas in Central Shandong and Jiaodong Peninsula have the most concentrated distribution of high-quality tourist attractions. 2) The distribution of high-quality tourist attractions shows a southwest‒northeast clustering direction; Qingdao is a high-high clustering area, and Heze is a low-high clustering area with low uniformity of spatial distribution and obvious spatial divergence. 3) Tourist attractions show an obvious "N" type high-density distribution belt and nuclear density distribution across the three existing agglomeration centers in the Jining–Tai'an intersection, Binzhou–Dongying intersection, and Qingdao Jiaozhou Bay coast. 4) Topography, climate conditions, history and culture are intrinsic factors affecting the spatial distribution of tourist attractions, while socioeconomic and transportation conditions are external requirements for the development thereof; collectively, they constrain the spatial distribution of high-quality tourist attractions. [ABSTRACT FROM AUTHOR]

Green tides caused by Ulva prolifera occur annually in the Yellow Sea, potentially influencing the marine microorganisms. Here, we focused on the variations in marine bacterial and archaeal communities during an U. prolifera green tide in coastal Qingdao areas with Illumina high-throughput sequencing analysis. Our results revealed that the diversity and structure of bacterial and archaeal communities, as well as the organization and structure of microbial co-occurrence networks, varied during the green tide. The decline phase may be favorable to the bacterial and archaeal diversity and richness. The bacterial community, as well as the archaeal community, showed clear variations between the outbreak and decline phases. A simpler and less connected microbial co-occurrence network was observed during the outbreak phase compared with the decline phase. Flavobacteriales and Rhodobacterales separately dominated the bacterial community during the outbreak and decline phase, and Marine Group II (MGII) dominated the archaeal community during the green tide. Combined with microbial co-occurrence network analysis, Flavobacteriales, Rhodobacterales and MGII may be important organisms during the green tide. Temperature, chlorophyll a content and salinity may have an important impact on the variations in bacterial and archaeal communities during the green tide. [ABSTRACT FROM AUTHOR]

Shewanella is a common bacterial genus in marine sediments and deep seas, with a variety of metabolic abilities, suggesting its important roles in the marine biogeochemical cycles. In this study, a novel lytic Shewanella phage, vB_SInP-X14, was isolated from the surface coastal waters of Qingdao, China. The vB_SInP-X14 contains a linear, double-strand 36,396-bp with the G + C content of 44.1% and harbors 40 predicted open reading frames. Morphological, growth, and genomic analysis showed that it is the first isolated podovirus infecting Shewanella , with a short propagation time (40 min), which might be resulted from three lytic-related genes. Phylogenetic analysis suggested that vB_SInP-X14 could represent a novel viral genus, named Bocovirus, with four isolated but not classified phages. In addition, 14 uncultured viral genomes assembled from the marine metagenomes could provide additional support to establish this novel viral genus. This study reports the first podovirus infecting Shewanella , establishes a new interaction system for the study of virus–host interactions, and also provides new reference genomes for the marine viral metagenomic analysis. [ABSTRACT FROM AUTHOR]

Green tide, a typical marine environmental disaster that profoundly influenced the coastal areas, has been occurred consecutively in the South Yellow Sea of China since 2007. Herein, the active microbial community structure and metabolic pathways in Qingdao offshore during an Ulva prolifera green tide were investigated by using metatranscriptomic approach. The dominant active microbial taxa at the outbreak phase were primarily a functional group that can utilize organic matters derived from U. prolifera , such as Lentibacter , Polaribacter and Planktomarina. While the taxa involved in biogeochemical cycles, including Phaeobacter , Pseudomonas and Marinobacterium , dominated the active microbial communities at the decline phase. The expression level of enzymes involved in U. prolifera polysaccharides degradation was significantly higher at the outbreak phase compared to the decline phase. At the same time, the main players Glaciecola and Polarbacter showed similar trends, suggesting that the low competitiveness for nutrients of related microorganisms at this phase made them degrade more U. prolifera polysaccharides to meet their own nutrient needs, thereby accelerating the degradation of U. prolifera. According to KEGG annotation, the biogeochemical pathways including nitrogen cycle, sulfur cycle and methane oxidation altered during the green tide, with thiosulfate oxidation and methane oxidation probably being the crucial pathways at the outbreak and the decline phase respectively. The coupling of sulfide oxidation and denitrification was also observed in this study. Furthermore, the green tide in Qingdao offshore might impact the greenhouse effects induced by CH 4 and N 2 O through influencing the related microbial processes. [Display omitted] • Active microbial community and metabolic pathways varied across phases of green tide. • High gene expression of U. prolifera polysaccharides at the outbreak phase. • Sulfide oxidation and denitrification might couple during the green tide. [ABSTRACT FROM AUTHOR]

Although Alteromonas is ubiquitous in the marine environment, very little is known about Alteromonas phages, with only ten, thus far, being isolated and reported on. In this study, a novel double-stranded DNA phage, Alteromonas phage P24, which infects Alteromonas macleodii, was isolated from the coastal waters off Qingdao. Alteromonas phage P24 has a siphoviral morphology, with an icosahedral head, 61 ± 1 nm in diameter, and a tail length of 105 ± 1 nm. Alteromonas phage P24 contains lipids. It has an optimal temperature and pH for growth of 20℃ and 5–7, respectively. A one-step growth curve shows a latent period of 55 min, a rise period of 65 min, and an average burst size of approximately 147 virions per cell. Alteromonas phage P24 has the genome of 46,945 bp with 43.80% GC content and 74 open reading frames (ORFs) without tRNA. The results of the phylogenetic tree, based on the mcp and terL genes, show that Alteromonas phage P24 is closely related to Aeromonas phage phiARM81ld. Meanwhile, phylogenetic analysis based on the whole genome of P24 indicates that it forms a unique viral sub-cluster within Siphoviridae. This study contributes to the understanding of the genomic characteristics and the virus-host interactions of Alteromonas phages. [ABSTRACT FROM AUTHOR]

Two novel Vibrio phages, LP.1 and LP.2 that infected Vibrio maritimus R-40493, were isolated from surface seawater in Qingdao coastal area by the double-agar layer method. Morphological analysis by transmission electron microscope showed that the two phages displayed head–tail structures with icosahedral heads of 62.37 and 54.00 nm in diameter and long non-contractile tails of 119.00 and 105.20 nm in length, respectively, and can be grouped into the Siphoviridae family. Thermal and pH sensitivity tests exhibited that LP.1 was stable at temperature ranging from − 20 to 65 °C and at pH ranging from 5 to 12, and LP.2 showed vitality over a wider range of temperature (− 20–75 °C) and pH (3–12). Both LP.1 and LP.2 contained linear and double-stranded DNA genomes with a length of 46,791-bp and 37,128-bp, respectively. The genome of both phages can be classified into four functional groups, including DNA replication and regulation, phage packaging, phage structure, and additional function. The bioinformatic analysis demonstrated that the Vibrio phages LP.1 and LP.2 are novel phages. By conducting morphological, biochemical, and genomic analysis, our study provides useful information for further research on the interaction between Vibrio phages and their host. [ABSTRACT FROM AUTHOR]

• A novel Vibrio cyclitrophicus phage vB_VviC_ZQ26 was isolated from the coastal water of Qingdao, China (120.327°E, 36.065°N). • Phage vB_VviC_ZQ26 represents a new family-level cluster, named Coheviridae, within the Caudoviricetes. • Two gene transfer agent proteins are encoded by phage vB_VviC_ZQ26, including baseplate attachment domain and central domain. • Phage vB_VviC_ZQ26 has a low relative abundance in the marine environment but one of the family members has high abundance. Vibrio is a prevalent bacterial genus in aquatic environments and exhibits diverse metabolic capabilities, playing a vital role in marine biogeochemical cycles. This study isolated a novel virus infecting Vibrio cyclitrophicus , vB_VviC_ZQ26, from coastal waters near Qingdao, China. The vB_VviC_ZQ26 comprises a linear double-stranded DNA genome with a length of 42,982 bp and a G + C content of 43.21 %, encoding 72 putative open reading frames (ORFs). Transmission electron microscope characterization indicates a siphoviral-morphology of vB_VviC_ZQ26. Nucleic-acids-wide analysis indicates a tetranucleotide frequency deviation for genomic segments encoding putative gene transfer agent protein (GTA) and coil-containing protein, implying divergent origins occurred in different parts of viral genomes. Phylogenetic and genome-content-based analysis suggest that vB_VviC_ZQ26 represents a novel vibriophage-specific family designated as Coheviridae. From the result of biogeographic analysis, Coheviridae is mainly colonized in the temperate and tropical epipelagic zones. This study describes a novel vibriophage infecting V. cyclitrophicus , shedding light on the evolutionary divergence of different parts of the viral genome and its ecological footprint in marine environments. [ABSTRACT FROM AUTHOR]

• A novel Stutzerimonas stutzeri phage vB_PstS_ZQG1 was isolated from the surface seawater of Qingdao, China. • Two AMGs are encoded by phage vB_PstS_ZQG1, including TolA protein and nucleotide pyrophosphohydrolase. • Phage vB_PstS_ZQG1 represents a new viral genus, named Fuevirus, within the caudoviricetes. • Phage vB_PstS_ZQG1 is predominantly found in the epipelagic and mesopelagic zones with low abundance. Stutzerimonas stutzeri is an opportunistic pathogenic bacterium belonging to the Gammaproteobacteria , exhibiting wide distribution in the environment and playing significant ecological roles such as nitrogen fixation or pollutant degradation. Despite its ecological importance, only two S. stutzeri phages have been isolated to date. Here, a novel S. stutzeri phage, vB_PstS_ZQG1, was isolated from the surface seawater of Qingdao, China. Transmission electron microscopy analysis indicates that vB_PstS_ZQG1 has a morphology characterized by a long non-contractile tail. The genomic sequence of vB_PstS_ZQG1 contains a linear, double-strand 61,790-bp with the G+C content of 53.24% and encodes 90 putative open reading frames. Two auxiliary metabolic genes encoding TolA protein and nucleotide pyrophosphohydrolase were identified, which are likely involved in host adaptation and phage reproduction. Phylogenetic and comparative genomic analyses demonstrated that vB_PstS_ZQG1 exhibits low similarity with previously isolated phages or uncultured viruses (average nucleotide identity values range from 21.7 to 29.4), suggesting that it represents a novel viral genus by itself, here named as Fuevirus. Biogeographic analysis showed that vB_PstS_ZQG1 was only detected in epipelagic and mesopelagic zone with low abundance. In summary, our findings of the phage vB_PstS_ZQG1 will provide helpful insights for further research on the interactions between S. stutzeri phages and their hosts, and contribute to discovering unknown viral sequences in the metagenomic database. [ABSTRACT FROM AUTHOR]

[Display omitted] • Construction of an interfacial steam generator by using nanocellulose extracted from marine biomass. • Rational fabrication of nanocellulose-based aerogels as structural elements. • Realization of a 3D monolithic interfacial steam generator for efficient and durable solar evaporation. Solar-driven interfacial evaporation is an emerging and sustainable technology with growing potential for applications in water distillation and desalination. Despite the ongoing progress in clean water production, the high cost, delicate structures, leaching and disposal of synthetic materials remain the major roadblocks toward large-scale and real-world applications. Herein, nanocellulose (NC) is successfully extracted from abundant, inexhaustible and biodegradable biomass Ulva (Enteromorpha) prolifera that collected from the coast of Qingdao, China. Incorporation of polyvinyl alcohol (PVA) into the NC scaffolds and subsequent cross-linking endow the composite aerogels with efficient water diffusion, enhanced mechanical strength and good deformation resistance. The cross-linked composite aerogels can serve as main structural elements and integrate a monolithic, self-floating and durable steam generator. Under one sun, the good water evaporation rate of 1.4 kg m−2 h−1 is among the best-performing interfacial steam generators constructed by using cellulose-based materials as structural components. This study demonstrates a new concept of using marine (blue) biomass-derived NC as crude material and building block to construct high-performance and durable interfacial steam generators, synergistically considering clean water production and sustainability of marine ecosystems. [ABSTRACT FROM AUTHOR]

• Phage AL can provide information for study of interaction between marine phage and host. • The order of the functional genes in phage AL is highly conserved and follows the common pattern used by siphovirus. • Pseudoalteromonas phage AL shows genetic plasticity and flexibility in evolution. Although Pseudoalteromonas is an abundant, ubiquitous, marine algae-associated bacterial genus, there is still little information on their phages. In the present study, a marine phage AL, infecting Pseudoalteromonas marina , was isolated from the coastal waters off Qingdao. The AL phage is a siphovirus with an icosahedral head of 53 ± 1 nm and a non-contractile tail, length of 99 ± 1 nm. A one-step growth curve showed that the latent period was approximately 70 min, the rise period was 50 min, and the burst size was 227 pfu/cell. The genome sequence of this phage is a 33,582 bp double-stranded DNA molecule with a GC content of 40.1 %, encoding 52 open reading frames (ORFs). The order of the functional genes, especially those related to the structure module, is highly conserved and basically follows the common pattern used by siphovirus. The stable order has been formed during the long-term evolution of phages in the siphovirus group, which has helped the phages to maintain their normal morphology and function. Phylogenetic trees based on the major capsid protein (mcp) and genome-wide sequence have shown that the AL phage is closely related to four Pseudoalteromonas phages, including PHS21, PHS3, SL25 and Pq0. Further analysis using all-to-all BLASTP also confirmed that this phage shared high sequence homology with the same four Pseudoalteromonas phages, with amino acid sequence identities ranging from 44 % to 71 %. In particular, their similarity in virion structure module may imply that these phages share common assembly mechanism characteristics and infection pathways. Pseudoalteromonas phage AL not only provides basic information for the further study of the evolution of Pseudoalteromonas phages and interactions between marine phage and host but also helps to explain the unknown viral sequences in the metagenomic databases. [ABSTRACT FROM AUTHOR]