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A taxonomic identification using polyphasic approach was performed on strain TH16-21 T , which was isolated from the interfacial sediment of Taihu Lake, PR China. Strain TH16-21 T was Gram-stain-negative, aerobic, rod-shaped and catalase-positive. Phylogenetic analysis based on the 16S rRNA gene and genomic sequences indicated that strain TH16-21 T was classified within the genus of Flavobacterium . The 16S rRNA gene sequence of strain TH16-21 T showed the highest similarity to Flavobacterium cheniae NJ-26 T (98.9 %). The average nucleotide identity and digital DNA-DNA hybridization values between strain TH16-21 T and F. cheniae NJ-26 T were 91.2 and 45.9 %, respectively. The respiratory quinone was menaquinone 6. The major cellular fatty acids (>10 %) comprised iso-C 15 : 0 , iso-C 16 : 0 , iso-C 15 : 1 G and iso-C 16 : 0 3-OH. The genomic DNA G+C content was 32.2 mol%. Phosphatidylethanolamine, six amino lipids and three phospholipids were the main polar lipids. Based on the phenotypic features and phylogenetic position, a novel species with the name Flavobacterium lacisediminis sp. nov. is proposed. The type strain is TH16-21 T (=MCCC 1K04592 T =KACC 22896 T ).

The variation of water level is the main environmental factor controlling the growth of aquatic vegetation. It is of significance to understand its influences on aquatic vegetation coverage in sub-lakes under different hydrolo-gical control modes. Taking the free connected sub-lake Bang Lake and locally controlled sub-lake Dahuchi Lake of Poyang Lake as a case and based on remote sensing cloud computing platform of the Google Earth Engine (GEE), we used the pixel binary model to estimate aquatic vegetation coverage from 2000 to 2019, and analyzed the temporal and spatial differentiation characteristics, and the variation trend was simulated by combining the method of Sen+M-K. We analyzed the water level change characteristics during the study period and the relationship between the hydrological parameters and the aquatic vegetation coverage area of sub-lakes with different hydrological connectivity was explored by setting up the water level fluctuation parameters. The results showed that the aquatic vegetation coverage of Bang Lake was more susceptible to water level changes, while Dahuchi Lake was more stable. The aquatic vegetation was patchily and sporadically distributed in the years with low vegetation coverage. In the years with high vegetation coverage, it was distributed in a ring-like pattern, spreading from the center of the lake to the shore. The aquatic vegetation coverage of Bang Lake was more likely influenced by water level fluctuation rate, while the aquatic vegetation coverage of Dahuchi Lake was more likely influenced by the flooding duration of 17 m characteristic water level. The flooding duration of 19 m characteristic water level had a strong negative correlation with the aquatic vegetation coverage of Bang Lake and Dahuchi Lake. The trend of aquatic vegetation in Bang Lake was dominated by stabilization and slight improvement, while that in Dahuchi Lake was dominated by stabilization and significant degradation. Our results could help to further understand the dynamics of water hydrological ecosystem with different hydrological connectivity and provide a reference for lake management and conservation.

A taxonomic identification using a polyphasic approach was performed on strain NBS58-1 T , which was isolated from the interfacial sediment of Taihu Lake in China. Strain NBS58-1 T was Gram-stain-negative, aerobic, non-spore-forming and catalase-positive. Phylogenetic analyses based on 16S rRNA gene and three housekeeping genes ( rpoB , gyrB and dnaK ) sequences supported the position that strain NBS58-1 T should be classified within the genus Rufibacter . The 16S rRNA gene sequence of strain NBS58-1 T possessed the highest similarity to Rufibacter sediminis H-1 T (96.60 %), followed by Rufibacter glacialis MDT1-10-3 T (96.17 %). And the ANI value between strain NBS58-1 T and R. glacialis MDT1-10-3 T was 79.3 %. The respiratory quinone was menaquinone 7 (MK-7). The major cellular fatty acids comprised iso-C 15 : 0 and summed feature 3. Phosphatidylethanolamine, two unidentified phospholipids and four unidentified lipids were the main polar lipids. The genomic DNA G+C content was 51.3 mol%. Based on phenotypic features and phylogenetic position, a novel species with the name Rufibacter hautae sp. nov. is proposed. The type strain is NBS58-1 T =(KACC 21309 T =MCCC 1K04037 T ). We also proposed Rufibacter quisquiliarum as a latter heterotypic synonym of Rufibacter ruber .

A Gram-stain-positive, strictly aerobic, motile and rod-shaped bacterium, designated strain LJ137 T , was isolated from the sediment of Taihu Lake in China. A polyphasic approach was used to investigate its taxonomic position. Strain LJ137 T grew optimally at pH 7.5, at 37 °C and with 2.5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain LJ137 T was most closely related to the genera Ornithinibacillus and Oceanobacillus . The closest phylogenetic neighbours were Ornithinibacillus halophilus KCTC 13822 T , Ornithinibacillus salinisoli LCB256 T and Oceanobacillus limi KCTC 13823 T , with 95.2, 96.5 and 95.6 % 16S rRNA gene sequence similarity, respectively. The peptidoglycan amino acid type was A4 α (l-Lys-d-Asp). The major respiratory quinone was menaquinone-7 (MK-7). The polar lipids of strain LJ137 T contained diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids, two aminophospholipids and one unidentified lipid. The G+C content of the genomic DNA was 40.4 mol%. The dominant cellular fatty acids were anteiso-C 15 : 0 , anteiso-C 17 : 0 and iso-C 15 : 0 . Based on the phenotypic, chemotaxonomic, phylogenetic and genome sequence characteristics of this strain, a novel species, Ornithinibacillus gellani sp. nov., is proposed. The type strain is LJ137 T (=CGMCC 1.13678 T =NBRC 113552 T ). An emended description of the genus Ornithinibacillus is presented.

A novel Gram-negative, aerobic, rod-shaped bacterium, designated NS26 T , was isolated from a sediment sample collected from Taihu Lake in China. Colonies were orange, circular, smooth and neat-edged on Reasoner's 2A agar. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain NS26 T belonged to the genus Brevundimonas and had the closest relationship with Brevundimonas halotolerans DSM 24448 T (96.9 %). It grew at 20-37 °C (optimum, 28 °C), pH 5.5-10.5 (pH 7.0) and without NaCl. The major isoprenoid quinone was Q-10. The dominant cellular fatty acids were C18 : 1ω7c, C16 : 0 and C18 : 1ω7c 11-methyl. The polar lipid profile comprised 1,2-diacyl-3-O-(6-phosphatidyl-α-d-glucopyranosyl) glycerol, 1,2-di-O-acyl-3-O-α-d-glycopyranuronosyl glycerol, sulfoquinovosyl diacylglycerol, 1,2-di-O-acyl-3-O-[d-glycopyranosyl-(1→4)-α-d-glucopyranuronosyl] glycerol and phosphatidylglycerol. The G+C content of genomic DNA was 68.4 mol%. The average nucleotide identity value between strain NS26 T and B.halotolerans DSM 24448 T was 75.6 %. Based on the polyphasic taxonomic study, strain NS26 T is suggested to be a novel species, for which the name Brevundimonas lutea sp. nov. is proposed. The type strain is NS26 T (=CGMCC 1.13680 T =NBRC 113554 T ).

An aerobic, motile, Gram-stain-negative bacterium, designated strain NS1 T , was isolated from interfacial sediment from Taihu Lake, China. The strain formed yellow colonies on R2A medium. Cells were ovoid to rod-shaped and non-spore-forming. Growth occurred at 15-40 °C (optimum, 28 °C), at pH 5.0-10.5 (optimum, 6.5-7.5) and in the presence of 0-1 % (w/v) NaCl (optimum, 0 %). Phylogenetic trees based on 16S rRNA gene sequences showed that strain NS1 T represented a member of the genus Altererythrobacter and had the highest sequence similarity to Altererythrobacter troitsensis CCTCC AB 2015180 T (97.1 %). The average nucleotide identity value between strain NS1 T and the closest related strain based on their genomes was 78.6 %. The predominant ubiquinone was Q-10. The major fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The polar lipids comprised diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, an unidentified phospholipid, an unidentified glycolipid and six unidentified lipids. The genomic DNA G+C content was 66.6 mol%. On the basis of phenotypic and genotypic characteristics, strain NS1 T represents a novel species of the genus Altererythrobacter, for which the name Altererythrobacter amylolyticus sp. nov. is proposed. The type strain is NS1 T (=CGMCC 1.13679 T =NBRC 113553 T ).

A novel Gram-stain-negative, aerobic and rod-shaped bacterial strain, designated H-1 T , was isolated from the interfacial sediment of Taihu Lake in China and characterized by using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the organism was most closely related to Rufibacter immobilis MCC P1 T and Rufibacter tibetensis 1351 T , with sequence similarities of 98.0 and 97.6 %, respectively. DNA-DNA relatedness between strain H-1 T and R. immobilis MCC P1 T and R. tibetensis 1351 T was 48.8 and 36.6 %, respectively. The major (>5 %) cellular fatty acids were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 1ω5c, iso-C15 : 0, summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B) and anteiso-C15 : 0. The polar lipids comprised phosphatidylethanolamine, three unidentified aminophospholipids, an unidentified phospholipid and three unidentified lipids. The major respiratory quinone was menaquinone 7 (MK-7). Genomic DNA G+C content was 49.0 mol%. Based on its physiological, biochemical and chemotaxonomic characteristics, the strain represents a novel species of the genus Rufibacter, for which the name Rufibacter sediminis sp. nov. (type strain H-1 T =CGMCC 1.16289 T =NBRC 113030 T ) is proposed.

A novel actinobacterial strain, designated X5 T , was isolated from the sediment of Taihu Lake in China and was subjected to a polyphasic taxonomic characterization. The strain formed orange-red colonies comprising aerobic, Gram-stain-negative, rod-shaped cells on R2A agar. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the organism was closely related to the genus Sporichthya and consistently formed a distinct clade along with the members of this genus. The closest phylogenetic neighbour was Sporichthya polymorpha NBRC 12702 T with 93.7 % 16S rRNA gene sequence similarity. The major fatty acids (>10 %) were iso-C16 : 0 (18.7 %), C18 : 1ω9c (18.6 %) and C17 : 1ω8c (14.0 %). The genomic DNA G+C content was 74.4 mol%. The organism contained menaquinone MK-8(H2), MK-9(H4) and an unidentified menaquinone. Polar lipids were composed of phosphatidylglycerol, an unidentified lipid, two unidentified phospholipids and two unidentified aminolipids. The whole-cell sugars contained ribose, xylose, mannose, glucose and galactose. The cell-wall peptidoglycan contained ll-diaminopimelic acid. Based on the physiological, biochemical and chemotaxonomic data, the organism is proposed to represent a novel genus and species, for which the name Longivirga aurantiaca gen. nov., sp. nov. is proposed. The type strain is X5 T (=CGMCC 4.7317 T =NBRC 112237 T ).

A novel actinobacterial strain, designated X17T, was isolated from the sediment of Taihu Lake in China and its taxonomic position was investigated by using a polyphasic approach. The isolate formed milky-white colonies comprising aerobic, Gram-stain-positive, rod-shaped cells. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the organism belonged to the genus Nocardioides and consistently formed a distinct cluster with Nocardioides agariphilus JCM 16020T and Nocardioides islandensis MSL 26T, sharing 95.5 and 94.8 % 16S rRNA gene sequence similarities, respectively. The genomic DNA G+C content was 69.9 mol%. Chemotaxonomically, the isolate contained ll-diaminopimelic acid in the cell-wall peptidoglycan, MK-8 (H4) as the predominant menaquinone, and diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol as the polar lipids found in the cell wall. The major fatty acids were 18 : 1 ω9c (38.6 %), 16 : 0 iso (20.3 %), 15 : 0 iso (6.8 %) and 18 : 0 (5.8 %). Based on its physiological, biochemical and chemotaxonomic characteristics, the strain represents a novel species of the genus Nocardioides, for which the name Nocardioides taihuensis sp. nov. (type strain X17T=CGMCC 4.7318T=NBRC 112321T) is proposed.

To investigate the temporal variation of the sediment prokaryote communities and their relation with the rapid increase of algae population in Taihu, a shallow eutrophic freshwater Lake, water and surface sediments were sampled from seven sites in different stages of algal bloom. The physicochemical characterization revealed positive correlations among the nutrient (N, P) parameters in the water and sediments, as well as TN/TP ratio 30.79 in average in water and 0.13 in sediments, demonstrating that P content was the limit factor for bloom in Taihu and sediment was an important nutrient resource for the water body. T-RFLP analysis of 16S rRNA genes revealed a diversity decrease of sediment prokaryotic communities along the bloom. The bacterial communities in sediments were more sensitive and shaped by the temporal changes, while archaea were more sensitive to the trophic level. The pyrosequencing data showed clear spatial and temporal changes in diversity of sediment bacteria. Betaproteobacteria was the most abundant group in all the samples, following by Delta-, Gama- and Alpha-proteobacteria, Acidobacteria, Chlorobi, Chloroflexi etc. At the genus level, Thiobacillus and Sulfuricurvum were the most dominant groups in the sediments, and the increase of Thiobacillus abundance in February might be used as bioindicator for the subsequent bloom. In addition, NO3 (-)-N was evidenced to be the main factor to regulate the bacterial community structure in the sediments. These results offered some novel and important data for the evaluation and predict the algal bloom in Taihu and can be reference for other shallow fresh water lakes.

An orange-pigmented, Gram-reaction-positive, non-spore-forming, halophilic, alkali-tolerant rod, designated strain halo-2(T), was isolated from sediment of Xiarinaoer soda lake, in China's Inner Mongolia Autonomous Region. Strain halo-2(T) grew in a complex medium with 3-30 % (w/v) NaCl and at pH 5-10. The cell-wall peptidoglycan contained meso-diaminopimelic acid and the major respiratory isoprenoid quinone was MK-7. The predominant cellular fatty acids were anteiso-C(15 : 0) (43.6 %), anteiso-C(17 : 0) (14.8 %) and iso-C(15 : 0) (6.8 %) and the polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The genomic DNA G+C content of the novel strain was 48.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain halo-2(T) was most closely related to Bacillus agaradhaerens DSM 8721(T) (93.9 % sequence similarity). However, strain halo-2(T) could be clearly differentiated from its closest phylogenetic relatives on the basis of several phenotypic, genotypic and chemotaxonomic characteristics. Strain halo-2(T) therefore represents a novel species in a new genus for which the name Salisediminibacterium halotolerans gen. nov., sp. nov. is proposed. The type strain of the type species is halo-2(T) (= CGMCC 1.7654(T) = NBRC 104935(T)).

A Gram-negative, rod-shaped, aerobic, non-motile, bacterium (YG-17(T)) was isolated from eutrophic Taihu lake sediment. Colonies grown on YG agar plates were circular, convex, and yellow-colored. On the basis of 16S rRNA gene sequence similarity, strain YG-17(T) was shown to be closely related to Novosphingobium aromaticivorum (97.9%), followed by Novosphingobium stygium (97.5%), Novosphingobium subterranea (96.9%) and Novosphingobium taihuense (96.7%). The DNA-DNA relatedness values of strain YG-17(T) to the most phylogenetically related species N. aromaticivorum and N. stygium were 14% and 21%, respectively. The G+C content of the genomic DNA was 63.2 mol%. The major respiratory quinone was ubiquinone-10 and major fatty acids were C(18:1 ω7c), C(17:1 ω6c) and C(14:0)2-OH. Sphingoglycolipids were present, and spermidine was detected as the major polyamine. According to comparative physiological and chemotaxonomic analysis, strain YG-17(T) is proposed to be a novel species of the genus Novosphingobium, with the name of Novosphingobium sediminis sp. nov. The type strain is YG-17(T) (NBRC 106119(T)= CGMCC 1.9114(T)).