Distinct strategies of the habitat generalists and specialists in sediment of Tibetan lakes.

Microbial metacommunities normally comprise generalists and specialists. Uncovering the mechanisms underlying the diversity patterns of these two sub-communities is crucial for aquatic biodiversity maintenance. However, little is known about the ecological assembly processes and co-occurrence patterns of the habitat generalists and specialists across large spatial scales in plateau lake sediments, particularly regarding their environmental adaptations. Here, we investigated assembly processes of the habitat generalists and specialists in sediment of Tibetan lakes and their role in the stability of metacommunity co-occurrence network. Our results showed that the habitat generalists exhibited broader environmental thresholds and closer phylogenetic clustering than specialist counterparts. In contrast, the specialists exhibited stronger phylogenetic signals of ecological preferences compared with the habitat generalists. Stochastic processes dominated the habitat generalist (63.2%) and specialist (81.3%) community assembly. Sediment pH was the major factor mediating the balance between stochastic and deterministic processes in the habitat generalists and specialists. In addition, as revealed by network analysis, the habitat specialists played a greater role in maintaining the stability of metacommunity co-occurrence network. The insights gained from this study can be helpful to understand the mechanisms underlying maintenance of sediment microbial diversity in plateau lakes.

Fate of glacier surface snow-originating bacteria in the glacier-fed hydrologic continuums.

Glaciers represent important biomes of Earth and are recognized as key species pools for downstream aquatic environments. Worldwide, rapidly receding glaciers are driving shifts in hydrology, species distributions and threatening microbial diversity in glacier-fed aquatic ecosystems. However, the impact of glacier surface snow-originating taxa on the microbial diversity in downstream aquatic environments has been little explored. To elucidate the contribution of glacier surface snow-originating taxa to bacterial diversity in downstream aquatic environments, we collected samples from glacier surface snows, downstream streams and lakes along three glacier-fed hydrologic continuums on the Tibetan Plateau. Our results showed that glacier stream acts as recipients and vectors of bacteria originating from the glacier environments. The contributions of glacier surface snow-originating taxa to downstream bacterial communities decrease from the streams to lakes, which was consistently observed in three geographically separated glacier-fed ecosystems. Our results also revealed that some rare snow-originating bacteria can thrive along the hydrologic continuums and become dominant in downstream habitats. Finally, our results indicated that the dispersal patterns of bacterial communities are largely determined by mass effects and increasingly subjected to local sorting of species along the glacier-fed hydrologic continuums. Collectively, this study provides insights into the fate of bacterial assemblages in glacier surface snow following snow melt and how bacterial communities in aquatic environments are affected by the influx of glacier snow-originating bacteria.

Horizontal and vertical gene transfer drive sediment antibiotic resistome in an urban lagoon system.

Rapid urbanization has resulted in pervasive occurrence of antibiotic resistance genes (ARGs) in urban aquatic ecosystems. However, limited information is available concerning the ARG profiles and the forces responsible for their assembly in urban landscape lagoon systems. Here, we employed high-throughput quantitative PCR (HT-qPCR) to characterize the spatial variations of ARGs in surface and core sediments of Yundang Lagoon, China. The results indicated that the average richness and absolute abundance of ARGs were 11 and 53 times higher in the lagoon sediments as compared to pristine reference Tibetan lake sediments, highlighting the role of anthropogenic activities in ARG pollution. Co-occurrence network analysis indicated that various anaerobic prokaryotic genera belonging to Alpha-, Deltaproteobacteria, Bacteroidetes, Euryarchaeota, Firmicutes and Synergistetes were the potential hosts of ARGs. The partial least squares-path modeling (PLS-PM) analysis revealed positive and negative indirect effects of physicochemical factors and heavy metals on the lagoon ARG profiles, via biotic factors, respectively. The horizontal (mediated by mobile genetic elements) and vertical (mediated by prokaryotic communities) gene transfer may directly contribute the most to drive the abundance and composition of ARGs, respectively. Furthermore, the neutral community model demonstrated that the assembly of sediment ARG communities was jointly governed by deterministic and stochastic processes. Overall, this study provides novel insights into the diversity and distribution of ARGs in the benthic habitat of urban lagoon systems and underlying mechanisms for the spread and proliferation of ARGs.

Haloactinobacterium glacieicola sp. nov., isolated from an ice core.

A Gram-stain-positive, rod-shaped and motile bacterium with lateral flagellum, designated T3246-1T, was isolated from an ice core, which was drilled from Hariqin Glacier on the Tibetan Plateau, PR China. It grew optimally at 20 °C, pH 7-8 and in the presence of 3 % (w/v) NaCl. The major fatty acid of strain T3246-1T was anteiso-C15 : 0. Major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol. MK-8 was the dominant isoprenoid quinone. The whole-cell sugars were rhamnose, xylose and mannose. The major cell-wall peptidoglycan was lysine. The genomic DNA G+C content of the strain was 71.4 mol%. Results of phylogenetic analysis based on 16S rRNA gene sequences showed that strain T3246-1T formed a lineage within the genus Haloactinobacterium and was closely related to Haloactinobacterium album YIM 93306T with 95.99 % similarity. The average nucleotide identity value between strain T3246-1T and Haloactinobacterium album YIM 93306T was 76.65 %. Based on phenotypic and chemotaxonomic characteristics, strain T3246-1T was considered to represent a novel species of the genus Haloactinobacterium, for which the name Haloactinobacterium glacieicola sp. nov. is proposed. The type strain is T3246-1T (=CGMCC 1.13535T=JCM 32923T).

Genomic, proteomic and bioinformatic analysis of two temperate phages in Roseobacter clade bacteria isolated from the deep-sea water.

BACKGROUND: Marine phages are spectacularly diverse in nature. Dozens of roseophages infecting members of Roseobacter clade bacteria were isolated and characterized, exhibiting a very high degree of genetic diversity. In the present study, the induction of two temperate bacteriophages, namely, vB_ThpS-P1 and vB_PeaS-P1, was performed in Roseobacter clade bacteria isolated from the deep-sea water, Thiobacimonas profunda JLT2016 and Pelagibaca abyssi JLT2014, respectively. Two novel phages in morphological, genomic and proteomic features were presented, and their phylogeny and evolutionary relationships were explored by bioinformatic analysis. RESULTS: Electron microscopy showed that the morphology of the two phages were similar to that of siphoviruses. Genome sequencing indicated that the two phages were similar in size, organization, and content, thereby suggesting that these shared a common ancestor. Despite the presence of Mu-like phage head genes, the phages are more closely related to Rhodobacter phage RC1 than Mu phages in terms of gene content and sequence similarity. Based on comparative genomic and phylogenetic analysis, we propose a Mu-like head phage group to allow for the inclusion of Mu-like phages and two newly phages. The sequences of the Mu-like head phage group were widespread, occurring in each investigated metagenomes. Furthermore, the horizontal exchange of genetic material within the Mu-like head phage group might have involved a gene that was associated with phage phenotypic characteristics. CONCLUSIONS: This study is the first report on the complete genome sequences of temperate phages that infect deep-sea roseobacters, belonging to the Mu-like head phage group. The Mu-like head phage group might represent a small but ubiquitous fraction of marine viral diversity.

Erythrobacter arachoides sp. nov., isolated from ice core.

A Gram-stain-negative, rod-shaped bacterial strain, designed RC4-10-4T, belonging to the genus Erythrobacter, was isolated from the East Rongbuk Glacier on the Tibetan Plateau. Strain RC4-10-4T grew optimally at pH 7.0, at 25 °C and in the presence of 2 % (w/v) NaCl. Summed feature 3 (C16 : 1 ω6c and/or iso-C15 : 0 2-OH), summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) and C16 : 0 were the major fatty acids. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, sphingoglycolipid and phosphatidylcholine. Carotenoid was detected in the cells. The DNA G+C content of the novel strain was 66.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain RC4-10-4T formed a distinct phylogenetic lineage within the cluster comprising Erythrobacter strains. Similarities between the 16S rRNA gene sequences of strain RC4-10-4T and the closely related strains Erythrobacter luteus KCTC 42179T, Erythrobacter gangjinensis KCTC 22330T, Erythrobacter odishensis KCTC 23981T and Erythrobacter atlanticuls KCTC 42697T were 98.0, 97.6, 97.5 and 97.2 %. The DNA-DNA hybridization values were 37.6, 15.4, 29.8 and 35.8 %, respectively. Based on the phenotypic and phylogenetic characteristics, strain RC4-10-4T represents a novel species of the genus Erythrobacter, for which the name Erythrobacter arachoides sp. nov. is proposed, with the type strain RC4-10-4T (=CGMCC 1.15507T=JCM 31277T).

Aureimonas glaciei sp. nov., isolated from an ice core.

A bacterial strain, B5-2T, was isolated from an ice core drilled from Muztagh Glacier, China. Strain B5-2T was a Gram-stain-negative, short rod-shaped, motile by polar flagella, aerobic bacterium. The major fatty acids of strain B5-2T were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and iso-C13 : 0. The G+C content of the DNA from strain B5-2T was 69.3 mol%. The predominant isoprenoid quinone of strain B5-2T was Q-10. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine, phosphatidylcholine, an unidentified phospholipid and sulfoquinovosyldiacylglycerol. Comparative 16S rRNA gene sequence analysis revealed that the novel strain B5-2T shared highest similarity (96.7 %) with Aureimonas altamirensis S21BT. On the basis of the results of this polyphasic study, strain B5-2T represents a novel species of the genus Aureimonas, for which the name Aureimonas glaciei sp. nov. is proposed. The type strain is B5-2T (=CGMCC 1.15493T=KCTC 52395T).

Polymorphobacter glacialis sp. nov., isolated from ice core.

A Gram-stain-negative, non-spore-forming, rod-shaped bacterium, B555-2T, was isolated from an ice core drilled from Muztagh Glacier on the Tibetan Plateau, China. According to phylogenetic analysis with 16S rRNA gene sequences, the novel strain was most closely related to Polymorphobacter fuscus D40PT and Polymorphobacter multimanifer 262-7T with 98.4 and 96.9 % similarity, respectively. It grew optimally at pH 7 and 15 °C with 0.6 % NaCl (m/v). Carotenoid was detected from the cells. Major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, sphingoglycolipid, phophatidylmonomethy lethanolamine, phophatidylcholine. The major fatty acids were summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) (42.8 %), summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) (28.8 %), C14 : 0 2-OH (10.1 %) and C16 : 0 (8.2 %). The predominant ubiquinone was Q-10. The DNA G+C content was 62.1 mol%. In DNA-DNA hybridization tests, strain B555-2T shared 21.9 and 18.6 % DNA-DNA relatedness with P. fuscus D40PT and P.multimanifer 262-7T, respectively. Accordingly, strain B555-2T represents a novel species in the genus Polymorphobacter, for which the name Polymorphobacter glacialis sp. nov. is proposed. The type strain is B555-2T (=CGMCC 1.15519T=KCTC 52396T).

The Underlying Ecological Processes of Gut Microbiota Among Cohabitating Retarded, Overgrown and Normal Shrimp.

Increasing evidence of tight links among the gut microbiota, obesity, and host health has emerged, but knowledge of the ecological processes that shape the variation in microbial assemblages across growth rates remains elusive. Moreover, inadequately control for differences in factors that profoundly affect the gut microbial community, hampers evaluation of the gut microbiota roles in regulating growth rates. To address this gap, we evaluated the composition and ecological processes of the gut bacterial community in cohabitating retarded, overgrown, and normal shrimps from identically managed ponds. Gut bacterial community structures were distinct (P = 0.0006) among the shrimp categories. Using a structural equation modeling (SEM), we found that changes in the gut bacterial community were positively related to digestive activities, which subsequently affected shrimp growth rate. This association was further supported by intensified interspecies interaction and enriched lineages with high nutrient intake efficiencies in overgrown shrimps. However, the less phylogenetic clustering of gut microbiota in overgrown and retarded subjects may offer empty niches for pathogens invasion, as evidenced by higher abundances of predicted functional pathways involved in disease infection. Given no differences in biotic and abiotic factors among the cohabitating shrimps, we speculated that the distinct gut community assembly could be attributed to random colonization in larval shrimp (e.g., priority effects) and that an altered microbiota could be a causative factor in overgrowth or retardation in shrimp. To our knowledge, this is the first study to provide an integrated overview of the direct roles of gut microbiota in shaping shrimp growth rate and the underlying ecological mechanisms.

Hymenobacter glacieicola sp. nov., isolated from glacier ice.

A Gram-stain-negative, rod-shaped, non-motile and red-pink-pigmented bacterial strain, designated B1909T, was isolated from an ice core drilled from Muztagh Glacier on the Tibetan Plateau, China. A phylogenetic tree based on 16S rRNA gene sequences showed that strain B1909T formed a lineage within the genus Hymenobacter and was closely related to Hymenobacter xinjiangensis X2-1gT (96.16 % similarity) and Hymenobacter psychrotolerans Tibet-IIU11T (95.99 %). The predominant fatty acids were iso-C15 : 0, summed feature 3 (C16 : 1ω7c/C16 : 1ω6c), summed feature 4 (iso-C17 : 1ω6c I/anteiso B), C16 : 1ω5c, anteiso-C15 : 0 and iso-C17 : 0 3-OH. The major menaquinone was MK-7. The major polar lipid was phosphatidylethanolamine. The DNA G+C content was 59 mol%. On the basis of the phenotypic, phylogenetic and chemotaxonomic data presented, strain B1909T is considered to represent a novel species of the genus Hymenobacter, for which the name Hymenobacterglacieicola sp. nov. is proposed; the type strain is B1909T (=JCM 30596T=CGMCC 1.12990T).

Massilia psychrophila sp. nov., isolated from an ice core.

A Gram-stain-negative, aerobic, rod-shaped, motile bacterium, strain B1555-1T, was isolated from an ice core drilled from Ulugh Muztagh Glacier, China. The optimum growth temperature of strain B1555-1T was 15 °C and optimum pH was 7. The major fatty acids of strain B1555-1T were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The predominant respiratory quinone was Q-8. The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. The DNA G+C content of strain B1555-1T was 66.0 mol%. In 16S rRNA gene sequence comparisons, strain B1555-1T was affiliated to the genus Massilia and shared 98.30 and 97.13 % similarity with Massilia eurypsychrophila B528-3T and Massilia niabensis 5420S-26T, respectively. The results of DNA-DNA hybridization revealed that strain B1555-1T showed 49.8 % relatedness with M. eurypsychrophila B528-3T and 38.5 % with M. niabensis 5420S-26T. Based on the genotypic and phenotypic evidence presented in this study, strain B1555-1T represents a novel species of the genus Massilia, for which the name Massilia psychrophila sp. nov. is proposed. The type strain is B1555-1T (=CGMCC 1.15196T=JCM 30813T).

Vertical variation of bacterial community in Nam Co, a large stratified lake in central Tibetan Plateau.

We assessed the vertical variation of bacterial abundance, diversity and community composition in deep, high-altitude (4730 m above sea level) Lake Nam Co. The bacterial abundance reduced with increasing depth, while bacterial diversity increased in the deeper bottom water. Pyrosequencing revealed that the bacterial community in the lake showed a pronounced vertical shift: the Bacteroidetes and Proteobacteria had relatively higher abundance in the epilimnion and metalimnion; the Firmicutes group dominated in the metalimnion; the Actinobacteria and Cyanobacteria mainly occupied the metalimnion and hypolimnion. Water temperature, conductivity, photosynthetically active radiation, and chlorophyll a were significantly correlated with the bacterial communities. These results indicated that the bacterial communities appeared to have an apparent vertical structure under lake stratification.

Marivirga lumbricoides sp. nov., a marine bacterium isolated from the South China Sea.

A novel, aerobic, heterotrophic, orange-pigmented, Gram-staining-negative, rod-shaped, gliding bacterial strain, designated JLT2000(T), was isolated from surface water of the South China Sea. The strain was oxidase- and catalase-positive. The major cellular fatty acids of strain JLT2000 T: were C12 : 0, iso-C15 : 1 G, iso-C15 : 0, iso-C17 : 0 3-OH, summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C18 : 0. MK-7 was the major respiratory quinone and the major polar lipids were phosphatidylcholine and phosphatidylethanolamine. The genomic DNA G+C content of strain JLT2000(T) was 37.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JLT2000(T) formed a branch within the genus Marivirga, but was clearly separated from the two established species of this genus, Marivirga tractuosa and Marivirga sericea. The 16S rRNA gene sequence similarity of strain JLT2000(T) with the type strains of these two species was 95.8 % and 96.1 %, respectively. Strain JLT2000(T) had a shorter cell length and wider growth range in different temperatures and salinities than those of Marivirga tractuosa NBRC 15989(T) and Marivirga sericea NBRC 15983(T). In addition, strain JLT2000(T) could utilize more carbon sources and hydrolyse more polymers than Marivirga tractuosa NBRC 15989(T) and Marivirga sericea NBRC 15983(T). Based on this polyphasic analysis, strain JLT2000(T) represents a novel species of the genus Marivirga, for which the name Marivirga lumbricoides sp. nov. is proposed. The type strain is JLT2000(T) ( = JCM 18012(T) = CGMCC 1.10832(T)).

Thiobacimonas profunda gen. nov., sp. nov., a member of the family Rhodobacteraceae isolated from deep-sea water.

A bacterial strain, JLT2016(T), was isolated from a sample of South-eastern Pacific deep-sea water. Cells were Gram-stain-negative, aerobic, devoid of flagella, motile by gliding and rod-shaped. Colonies were mucoid and cream. Growth occurred at 1.0-11.0 % (w/v) NaCl, 10-40 °C and pH 4.0-9.0. The major fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) (60.5 %), C19 : 0 cyclo ω8c (10.9 %) and C16 : 0 (9.0 %). The polar lipids included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and two sphingoglycolipids. The DNA G+C content was 67.1 mol%. The closest relative of strain JLT2016(T) was Salipiger mucosus A3(T) (96.7 % 16S rRNA gene sequence similarity). The results of phylogenetic analyses with different treeing algorithms indicated that this strain belonged to the Roseobacter clade in the order Rhodobacterales. Based on polyphasic analysis, strain JLT2016(T) is considered to represent a novel genus and species, for which the name Thiobacimonas profunda gen. nov., sp. nov. is proposed. The type strain is JLT2016(T) ( = LMG 27365(T) = CGMCC 1.12377(T)).

Gramella flava sp. nov., a member of the family Flavobacteriaceae isolated from seawater.

A novel Gram-negative, yellow-pigmented, aerobic, motile by gliding, rod-shaped marine bacterium (JLT2011(T)) was isolated from surface seawater. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JLT2011(T) could be assigned to the genus Gramella and was most closely related to Gramella gaetbulicola, with 96.2 % similarity. The genomic DNA G+C content was 42.1 %. The predominant fatty acids were C16 : 0, iso-C15 : 0, C18 : 0 and summed feature 3 (C16 : 1ω6c/C16 : 1ω7c). The major menaquinone was MK-6. The major components of the polar lipid profile were phosphatidylglycerol, diphosphatidylglycerol and sphingoglycolipid. On the basis of phenotypic, genotypic and taxonomic data presented, strain JLT2011(T) is considered to represent a novel species of the genus Gramella, for which the name Gramella flava sp. nov. is proposed; the type strain is JLT2011(T) ( = CGMCC 1.12375(T) = LMG 27360(T)).

Parvularcula oceani [corrected] sp. nov., isolated from deep-sea water of the Southeastern Pacific Ocean.

A Gram-negative, aerobic, motile by single polar flagellum, short rod-shaped bacterium was isolated from a deep-seawater sample of the Southeastern Pacific Ocean. Growth was found to occur at 10-40 °C, at pH 4.0-10.0 and in the presence of 0-9.0 % (w/v) NaCl. The phylogenetic tree based on 16S rRNA gene sequences showed that strain JLT2013(T) fell within a clade comprising species of the genus Parvularcula and formed a coherent cluster with Parvularcula lutaonensis CC-MMS-1(T) (neighbour-joining phylogenetic tree) or Parvularcula dongshanensis SH25(T) (maximum-likelihood and maximum-parsimony phylogenetic trees). Sequence similarity analyses based on 16S rRNA gene sequences revealed that strain JLT2013(T) shows high sequence similarity to P. lutaonensis CC-MMS-1(T) (96.7 %), P. dongshanensis SH25(T) (96.0 %) and Parvularcula bermudensis HTCC2503(T) (95.2 %). The major cellular fatty acids were identified as C12:0 (34.3 %), summed feature 8 (C18:1 ω7c and/or C18:1 ω6c) (10.9 %), C16:0 (10.0 %) and C17:1 ω6c (7.2 %). The polar lipids were found to include diphosphatidylglycerol, phosphatidylglycerol, three sphingoglycolipids and three unknown glycolipids. Strain JLT2013(T) was found to contain Q-10 as the predominant quinone. The DNA G+C content was determined to be 66.3 mol%. In the light of the phenotypic characteristics, chemotaxonomic features and phylogenetic evidence gathered in this study, strain JLT2013(T) (=LMG 27362(T) = CGMCC 1.12400(T)) should be classified as a novel species in the genus Parvularcula, for which the name Parvularcula oceani [corrected] sp. nov. is proposed.

Pelagibaca abyssi sp. nov., of the family Rhodobacteraceae, isolated from deep-sea water.

A Gram-stain negative, oval-shaped, aerobic, catalase and oxidase-positive bacterium, designated JLT2014(T), was isolated from a deep-seawater sample (obtained at a 2,000 m depth) of the Southeastern Pacific Ocean. The dominant fatty acids were identified as C18:1ω7c/C18:1ω6c, C16:0 and C10:0 3-OH, which altogether represented 60.1 % of the total. The predominant respiratory quinone was identified as Q-10. The G+C content of genomic DNA was determined to be 66.4 mol %. The major polar lipids were identified as phosphatidylethanolamine and diphosphatidylglycerol. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the novel isolate can be affiliated with the Roseobacter clade within the family Rhodobacteraceae. Strain JLT2014(T) exhibited highest 16S rRNA gene sequence similarity value to Pelagibaca bermudensis HTCC2601(T) (sequence similarity value: 97.6 %). The DNA-DNA relatedness value between strain JLT2014(T) and P. bermudensis HTCC2601(T) was 46.9 ± 2 %. Based on phenotypic properties and phylogenetic analysis, the name Pelagibaca abyssi sp. nov. is proposed, with JLT2014(T)(=LMG 27363(T)=CGMCC 1.12376(T)) as the type strain.

Pacificamonas flava gen. nov., sp. nov., a novel member of the family Sphingomonadaceae isolated from the Southeastern Pacific.

Strain JLT2015(T) was isolated from surface seawater of the Southeastern Pacific. The strain was Gram-negative, aerobic, motile by gliding, and rod shaped. The dominant fatty acids were C18:1ω7c, C16:0, and C16:1ω7c. The major respiratory ubiquinone was Q-10, and the predominant polyamine pattern was spermidine. The components of the polar lipid profile were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and sphingoglycolipid. The DNA G+C content was 64.2 %. Phylogenetic analysis based on 16S rRNA gene sequence revealed strain JLT2015(T) belonged to belong to the family Sphingomonadaceae, exhibiting 94.7 % 16S rRNA gene sequence similarity with Novosphingobium pentaromativorans. On the basis of the taxonomic data presented, together with phylogenetic and genetic characteristics, strain JLT2015(T) is considered to represent a novel genus, for which the name Pacificamonas flava gen. nov., sp. nov. is proposed. The type strain of Pacificamonas flava is JLT2015(T) (=LMG27364(T) = CGMCC1.12401(T)).

Bacterial diversity in a continuum from supraglacial habitats to a proglacial lake on the Tibetan Plateau.

Mountain glaciers are frequently assessed for their hydrological connectivity from glaciers to proglacial lakes. Ecological process on glacier surfaces and downstream ecosystems have often been investigated separately, but few studies have focused on the connectivity between the different glacial habitats. Therefore, it remains a limited understanding of bacterial community assembly across different habitats along the glacier hydrological continuum. In this study, we sampled along a glacial catchment from supraglacial snow, cryoconite holes, supraglacial runoff, ice-marginal moraine and proglacial lake on the Tibetan Plateau. The bacterial communities in these habitats were analyzed using high-throughput DNA sequencing of the 16S rRNA gene to determine the bacterial composition and assembly. Our results showed that each habitat hosted unique bacterial communities, with higher bacterial α-diversity in transitional habitats (e.g. runoff and ice-marginal moraine). Null model analysis indicated that deterministic processes predominantly shaped bacterial assembly in snow, cryoconite holes and lake, while stochastic process dominantly governed bacterial community in transitional habitats. Collectively, our findings suggest that local environment play a critical role in filtering bacterial community composition within glacier habitats. This study enhances our understanding of microbial assembly process in glacier environments and provides valuable insights into the factors governing bacterial community compositions across different habitats along the glacial hydrological continuum.