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A Gram-stain-negative, yellow-pigmented, non-flagellated, motile by gliding, aerobic and rod-shaped bacterial strain, designated SM2212 T , was isolated from intertidal sediment of Aoshan Bay in Qingdao, China. The strain grew at 5-35 °C and with 0.5-5.5% NaCl (w/v). It was able to reduce nitrate to nitrite and hydrolyse starch, gelatin and DNA. The phylogenetic trees based on the 16S rRNA genes and single-copy genes showed that strain SM2212 T belonged to the genus Christiangramia within the family Flavobacteriaceae , sharing the highest 16S rRNA gene sequence similarity with the type strain of Christiangramia echinicola (97.1%) and 96.2-97.0% 16S rRNA gene sequence similarity with those of other known species in the genus. The major cellular fatty acids were summed feature 3 (C 16:1 ω7с and/or C 16:1 ω6с ), iso-C 15:0 , iso-C 17: 0 3-OH, summed feature 9 (iso-C 17:1 . The major polar lipids were phosphatidylethanolamine and an unidentified lipid. The genomic DNA G+C content of strain SM2212  ω9c and/or 10-methyl C 16:0 and type strains of closely related known 16:0 . The major polar lipids were phosphatidylethanolamine and an unidentified lipid. The genomic DNA G+C content of strain SM2212 T was 37.0 mol%. The digital DNA-DNA hybridization and average nucleotide identity values between strain SM2212 T and type strains of closely related known Christiangramia species were below 22.2 and 79.7%, respectively. Based on the polyphasic taxonomic analysis in this study, strain SM2212 T is considered to represent a novel species in the genus Christiangramia , for which the name Christiangramia sediminicola is proposed. The type strain is SM2212 T (=KCTC 92980 T =MCCC 1K07684 T ).

A Gram-stain-positive, aerobic, non-mobile and spherical strain, designated ZS9-10 T , belonging to the genus Deinococcus was isolated from soil sampled at the Chinese Zhong Shan Station, Antarctica. Growth was observed in the presence of 0-4 % (w/v) NaCl, at pH 7.0-8.0 and at 4-25 °C. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain ZS9-10 T formed a lineage in the genus Deinococcus . It exhibited highest sequence similarity (97.4 %) to Deinococcus marmoris DSM 12784 T . The major phospholipids of ZS9-10 T were unidentified phosphoglycolipid, unidentified glycolipids and unidentified lipids. The major fatty acids were summed feature 3 (C 16 : 1  ω 7 c and/or C 16 : 1  ω 6 c ), C 16 : 0 and C 16 : 1  ω 7 c . MK-8 was the predominant respiratory quinone. The digital DNA-DNA hybridization and average nucleotide identity values between strain ZS9-10 T and its close relative D. marmoris DSM 12784 T were 27.4 and 83.9 %, respectively. Based on phenotypic, phylogenetic and genotypic data, a novel species, named Deinococcus arenicola sp. nov., is proposed. The type strain iis ZS9-10 T (=CCTCC AB 2019392 T =KCTC43192 T ).

A Gram-stain-negative, aerobic, rod-shaped and halotolerant bacterium, designated as strain ASW11-75 T , was isolated from intertidal sediments in Qingdao, PR China, and identified using a polyphasic taxonomic approach. Growth of strain ASW11-75 T occurred at 10-45 °C (optimum, 37 °C), pH 6.5-9.0 (optimum, pH 8.0) and 0.5-18.0 % NaCl concentrations (optimum, 2.5 %). Phylogenetic analyses based on 16S rRNA gene sequences and 1179 single-copy orthologous clusters indicated that strain ASW11-75 T is affiliated with the genus Marinobacter . Strain ASW11-75 T showed highest 16S rRNA gene sequence similarity to ' Marinobacter arenosus ' CAU 1620 T (98.5 %). The digital DNA-DNA hybridization and average nucleotide identity values between strain ASW11-75 T and its closely related strains ( Marinobacter salarius R9SW1 T , Marinobacter similis A3d10 T , ' Marinobacter arenosus ' CAU 1620 T , Marinobacter sediminum R65 T , Marinobacter salinus Hb8 T , Marinobacter alexandrii LZ-8 T and Marinobacter nauticus ATCC 49840 T ) were 19.8-24.5 % and 76.6-80.7 %, respectively. The predominant cellular fatty acids were C 16 : 0 , C 18 : 1  ω 9 c and C 16 : 0 had lower protein isoelectric points with higher ratios of acidic residues to basic residues and possessed genes related to ion transport and organic osmoprotectant uptake, implying its potential tolerance to salt. The results of polyphasic characterization indicated strain ASW11-75 T had lower protein isoelectric points with higher ratios of acidic residues to basic residues and possessed genes related to ion transport and organic osmoprotectant uptake, implying its potential tolerance to salt. The results of polyphasic characterization indicated strain ASW11-75 T represents a novel Marinobacter species, for which the name Marinobacter qingdaonensis sp. nov. with the type strain ASW11-75 T is proposed. The type strain is ASW11-75 T (=KCTC 82497 T =MCCC 1K05587 T ).

A Gram-stain-negative, facultative anaerobic, methylphosphonate-decomposing, motile by a polar flagellum and rod-shaped marine bacterium, designated S4B1 T , was isolated from the surface seawater collected from the Yongle Atoll (Xisha Islands, PR China). The pairwise alignment showed the highest sequence similarity of 97.5 and 96.6 % to Vibrio aestuarianus subsp. cardii 12_122_3T3 T and Vibrio atypicus HHS02 T , respectively. Phylogenetic analysis based on 16S rRNA gene and the phylogenomic analysis of single-copy genes showed that strain S4B1 T belonged to the genus Vibrio and formed a close branch with Vibrio qingdaonensis ZSDZ65 T . Growth of strain S4B1 T occurred at 4-30 °C (optimum, 28 °C), at pH 6.0-8.0 (optimum, pH 7.0) and in the presence of 2-7 % (w/v) NaCl (optimum, 3 %). The predominant fatty acids (>10 %) were C16 : 0, iso-C 16 : 0 and summed feature 3 (C 16 : 1  ω 7 c or/and C 16 : 1 ). The DNA G+C content of the assembled genomic sequence was 44.3 mol%. Average nucleotide identity (ANI) values between S4B1  ω 6 c ). The DNA G+C content of the assembled genomic sequence was 44.3 mol%. Average nucleotide identity (ANI) values between S4B1 T and its reference species were lower than the threshold for species delineation (95-96 %), in which its highest ANI value with V. qingdaonensis ZSDZ65 T had less than 70 % similarity to its relatives. On the basis of the polyphasic evidence, strain S4B1 In silico is proposed to represent a novel species of the genus T had less than 70 % similarity to its relatives. On the basis of the polyphasic evidence, strain S4B1 T is proposed to represent a novel species of the genus Vibrio , for which the name Vibrio methylphosphonaticus sp. nov. is proposed. The type strain is S4B1 T (=KCTC 92311 T =MCCC 1K06168 T ).

A Gram-stain-negative, facultative anaerobic, rod-shaped strain, named SDRW27 T , was isolated from offshore seawater collected near Qingdao. Strain SDRW27 T was able to grow at 16-37 °C (optimum, 28 °C), pH 6.0-9.0 (optimum, pH 6.0) and in the presence of 1-7 % (w/v) NaCl (optimum, 3 %). Phylogenetic analysis using 16S rRNA gene sequences indicated that strain SDRW27 T was most closely related to Photobacterium toruni H01100410B T (97.89 % sequence similarity), Photobacterium andalusiense H01100409B T (97.89 %) and Photobacterium leiognathi ATCC 25521 T (97.82 %). The predominant fatty acids were summed feature 3 (C 16 : 1  ω7 c and/or iso-C 15 : 0 2-OH), summed feature 8 (C 18 : 1  ω 7 c and/or C 18 : 1  ω . The polar lipids of strain SDRW27 c comprised phosphatidylglycerol, phosphatidylinositol dimannoside, phosphatidylcholine, phosphatidylethanolamine and three unidentified lipids. The major respiratory quinone was ubiquinone-8. The G+C content was 47.71 mol%. The genome size was 5.84 Mbp, including 85 contigs with an N50 value of 223 542. The average nucleotide identity (ANI) values of SDRW27 16 : 0 . The polar lipids of strain SDRW27 T comprised phosphatidylglycerol, phosphatidylinositol dimannoside, phosphatidylcholine, phosphatidylethanolamine and three unidentified lipids. The major respiratory quinone was ubiquinone-8. The G+C content was 47.71 mol%. The genome size was 5.84 Mbp, including 85 contigs with an N50 value of 223 542. The average nucleotide identity (ANI) values of SDRW27 T with its three most similar strains, P. toruni H01100410B T , P. andalusiense H01100409B T , were 71.36, 71.58 and 72.23 %, respectively (all lower than the 95-96 % ANI threshold), and the DNA-DNA hybridization (DDH) values were 20.4, 20.8 and 20.4 % (all lower than the 70 % DDH threshold). The obtained results of polyphasic analysis demonstrate that strain SDRW27 P. leiognathi ATCC 25521 T , were 71.36, 71.58 and 72.23 %, respectively (all lower than the 95-96 % ANI threshold), and the DNA-DNA hybridization (DDH) values were 20.4, 20.8 and 20.4 % (all lower than the 70 % DDH threshold). The obtained results of polyphasic analysis demonstrate that strain SDRW27 T represents a novel species, for which the name Photobacterium obscurum sp. nov. is proposed. The type strain is SDRW27 T (=MCCC 1K06286 T =KCTC 82892 T ).

An exopolysaccharide-producing bacterial strain GW4-15 T , belonging to the genus Kaistella , was isolated from intertidal sediment from King George Island, Antarctic. The strain was Gram-stain-negative, aerobic, rod-shaped, non-motile and yellow-pigmented. The strain was able to grow in the presence of 0-2 % (w/v) NaCl (optimum, 0 %), at 4-30 °C (optimum, 20-28 °C) and at pH 5.0-10.0 (optimum, pH 8.0). A phylogenetic tree based on 16S rRNA gene sequences showed that strain GW4-15 T formed a lineage within the genus Kaistella with the closest phylogenetic neighbours Kaistella carnis NCTC 13525 T (98.3 %), Kaistella gelatinilytica G5-32 T (97.7 %), Kaistella antarctica LMG 24720 T (97.4 %) and Kaistella yonginensis HMD1043 T (96.9 %). Digital DNA-DNA hybridization values of strain GW4-15 T with K. carnis NCTC 13525 T , K. antarctica LMG 24720 T , K. gelatinilytica G5-32 T and K. yonginensis HMD1043 T were 22.8, 22.0, 21.7 and 21.6 %, respectively. The average nucleotide identity values between strain GW4-15 T and K. carnis NCTC 13525 T , K. antarctica LMG 24720 T , K. gelatinilytica G5-32 T and K. yonginensis were 79.3, 78.6, 77.5 and 77.2 %, respectively. The G+C content of the genome was 36.2 mol%. The major phospholipids were phosphatidylethanolamine and aminophospholipid. The predominant menaquinone was MK-6. The major fatty acids were anteiso-C T were 79.3, 78.6, 77.5 and 77.2 %, respectively. The G+C content of the genome was 36.2 mol%. The major phospholipids were phosphatidylethanolamine and aminophospholipid. The predominant menaquinone was MK-6. The major fatty acids were anteiso-C 15 : 0 (28.7 %), iso-C 16 : 0 3-OH (15.7 %), iso-C 16 : 0  H (10.0 %), iso-C 16 : 0 (5.4 %), summed feature 9 (comprising iso-C 17 : 1  ω 9 c (5.1 %). The monosaccharide composition of the new type of extracellular polymeric of GW4-15 16 : 0 was Glc, GalN, GlcN, Rha, Man and Gal with a molar ratio of 3.14 : 3.83 : 8.38 : 5.16 : 1 : 2.82. Based on phenotypic, phylogenetic and genotypic data, a novel species, 15 : 0 (5.1 %). The monosaccharide composition of the new type of extracellular polymeric of GW4-15 T was Glc, GalN, GlcN, Rha, Man and Gal with a molar ratio of 3.14 : 3.83 : 8.38 : 5.16 : 1 : 2.82. Based on phenotypic, phylogenetic and genotypic data, a novel species, Kaistella polysaccharea sp. nov., is proposed with the type strain GW4-15 T (=CGMCC 1.19368 T =KCTC 92753 T ).

A Gram-stain-positive, strictly aerobic, rod-shaped actinobacterium, designated strain ZYF776 T , was isolated from seawater of the Mariana Trench collected at a depth of 4000 m. Results of 16S rRNA gene sequence analysis indicated that strain ZYF776 T was a member of the class Nitriliruptoria and closely related to Nitriliruptor alkaliphilus DSM 45188 T (member of the order Nitriliruptorales , 94.94 % sequence similarity) and Egicoccus halophilus KCTC 33612 T (member of the order Egicoccales , 94.46 %). Strain ZYF776 T was catalase-positive and oxidase-negative. Growth occurred at 16-37 °C (optimum, 28 °C), in the presence of 0-13 % NaCl (w/v; optimum, 4 %) and at pH 7.0-10.0 (optimum, pH 8.0). Cell-wall hydrolysates of strain ZYF776 T contained meso -diaminopimelic (peptidoglycan type A1γ), with ribose, rhamnose and a smaller amount of xylose as the cell-wall sugars. The major menaquinone was MK-10. The predominant fatty acids (>10 %) were C 16:0 , C 17:1 ω 8 c and summed feature 3 (C 16 : 1 ω 7 c ). The polar lipid profile mainly contained diphosphatidylglycerol, phosphatidylglycerol and phosphoglycolipid. The genomic DNA G+C content of strain ZYF776 16 : 1 was 68.7 mol%. The genome of strain ZYF776 ω was about 5.61 Mbp in size, which was larger than those of the reference strains c ). The polar lipid profile mainly contained diphosphatidylglycerol, phosphatidylglycerol and phosphoglycolipid. The genomic DNA G+C content of strain ZYF776 T was 68.7 mol%. The genome of strain ZYF776 T was about 5.61 Mbp in size, which was larger than those of the reference strains N. alkaliphilus DSM45188 T (5.56 Mbp) and E. halophilus KCTC 33612 T (3.98 Mbp). The average nucleotide identity and digital DNA-DNA hybridization values between ZYF776 T and the related strains N. alkaliphilus DSM 45188 T and E. halophilus KCTC 33612 T were 76.7 and 20.3 % and 75.8 and 20.0 %, respectively. Based on the polyphasic evidence, a novel genus and species with the name Profundirhabdus halotolerans gen. nov., sp. nov. is proposed. The type strain is ZYF776 T (=JCM 33008 T =MCCC 1K03555 T ).

A Gram-stain-negative, aerobic, flagellated, and long rod-shaped bacterium, designated strain SM1973 T , was isolated from an intertidal sediment sample collected from the coast of Qingdao, PR China. Strain SM1973 T grew at 15-37 °C and with 0-5.5 % NaCl. It reduced nitrate to nitrite and hydrolysed aesculin but did not hydrolyse casein and gelatin. The strain showed the highest 16S rRNA gene sequence similarity (98.2 %) to the type strain of Spartinivicinus ruber . The phylogenetic trees based on the 16S rRNA genes and single-copy orthologous clusters showed that strain SM1973 T clustered with S. ruber , forming a separate lineage within the family Zooshikellaceae . The major cellular fatty acids were summed feature 3 (C 16 : 1 ω 7 с and/or C 16 : 1 ω . The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The main respiratory quinone was ubiquinone-9. The genomic DNA G+C content of strain SM1973 с ) and C 16 : 0 . The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The main respiratory quinone was ubiquinone-9. The genomic DNA G+C content of strain SM1973 T was 40.4 mol%. Based on the polyphasic evidence presented in this paper, strain SM1973 T is considered to represent a novel species within the genus Spartinivicinus , for which the name Spartinivicinus marinus sp. nov. is proposed. The type strain is SM1973 T (=MCCC 1K04833 T =KCTC 72846 T ).

A Gram-stain-negative, strictly aerobic, rod-shaped and non-flagellated marine bacterium, designated strain LXI357 T , was isolated from deep-sea water sampled at the Tangyin hydrothermal field in the Okinawa Trough. The growth temperature range was 20-45 °C (optimum, 28 °C). Strain LXI357 T was also able to grow at pH 5.0-7.5 (optimum, pH 6.0-7.0) and in the presence of 0.5-11 % (optimum, 7%, w/v) NaCl. Strain LXI357 T was oxidase-negative and catalase-positive. The predominant fatty acids were C 18 : 1  ω 7 c . The major polar lipids of strain LXI357 16 : 0 contained phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, phospholipid, sphingoglycolipid, diphosphatidylglycero and an unidentified aminolipid. Based on the results of 16S rRNA gene sequence analysis, strain LXI357 T contained phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, phospholipid, sphingoglycolipid, diphosphatidylglycero and an unidentified aminolipid. Based on the results of 16S rRNA gene sequence analysis, strain LXI357 T belonged to the genus Stakelama and was most closely related to Stakelama flava CBK3Z-3 T (96.28%, 16S rRNA gene sequence similarity), followed by Stakelama algicida Yeonmyeong 1-13 T (95.67%), Stakelama pacifica JLT832 T (95.46%) and Sphingosinicella vermicomposti YC7378 T (95.43%). Genome relatedness between strain LXI357 T and Stakelama flava was computed using average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity, with values of 76.02, 20.9 and 71.1 %, respectively. The genomic DNA G+C content of strain LXI357 T was computed using average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity, with values of 76.02, 20.9 and 71.1 %, respectively. The genomic DNA G+C content of strain LXI357 T is 64.1 mol%. In addition, strain LXI357 T from its closest phylogenetic neighbours. According to the results of polyphasic analyses, strain LXI357 T is considered to represent a novel species of the genus T is considered to represent a novel species of the genus Stakelama , for which the name Stakelama marina sp. nov. is proposed. The type strain is LXI357 T (=MCCC 1K06076 T =KCTC 82726 T ).

Two Gram-stain-negative, facultatively anaerobic, motile, rod-shaped and flagellated marine bacteria, designated strains DBSS07 T and ZSDZ65 T , were isolated from the surface sediments of the Bohai sea and Qingdao coastal seawater, respectively. Phylogenetic analysis based on 16S rRNA genes, multilocus sequence analysis (MLSA), phylogenomic analysis of single-copy gene families and whole-genome data placed DBSS07 T and ZSDZ65 T within the genus Vibrio . DBSS07 T was most closely related to Vibrio aestivus M22 T , with 97.51 % sequence similarity, whereas ZSDZ65 T was most closely related to Vibrio variabilis R-40492 T with 97.58 % sequence similarity. DBSS07 T grew with 1-7 % (w/v) NaCl (optimum 3 %), at 16-37 °C (optimum 28 °C) and at pH 6.0-9.0 (optimum pH 7.0); whereas ZSDZ65 T grew with 1-5 % (w/v) NaCl (optimum 2 %), at 16-32 °C (optimum 28 °C) and at pH 6.0-9.0 (optimum pH 8.0). Both strains shared the same major fatty acid components (more than 10 % of total fatty acids) of summed feature 3 (C 16 : 1 ω7 c or/and C 16 : 1 ω6 c ), with different proportions. The DNA G+C contents of DBSS07 T and ZSDZ65 T were 44.7 and 44.3 %, respectively. On the basis of the results of polyphasic analysis, DBSS07 T and ZSDZ65 T are considered to represent novel species within the genus Vibrio , for which the names V. paucivorans sp. nov. (type strain, DBSS07 T = KCTC 82896 T = MCCC 1K06284 T ) and V. qingdaonensis sp. nov. (type strain, ZSDZ65 T = KCTC 82893 T = MCCC 1K06289 T ) are proposed, respectively.

A Gram-stain-negative, aerobic, rod-shaped, non-gliding bacterial strain, designated as MT39 T , was isolated from a deep-sea sediment sample collected from the Mariana Trench. Strain MT39 T grew optimally at 35°C and pH 7.0, and could tolerate up to 10% (w/v) NaCl. The strain was positive for catalase and negative for oxidase. The genome of strain MT39 T was 4 033 307 bp, with a 41.1 mol % genomic G+C content and 3514 coding sequences. Phylogenetic analysis based on 16S rRNA gene sequences placed strain MT39 T within the genus Salinimicrobium , showing the highest 16S rRNA gene sequence similarity to Salinimicrobium terrea CGMCC 1.6308 T (98.1%). The average nucleotide identity and in silico DNA-DNA hybridization values between strain MT39 T and the type strains of seven Salinimicrobium species were all less than the threshold values to discriminate bacterial species, indicating that strain MT39 T is affiliated with a novel species within the genus. The major cellular fatty acids of strain MT39 T were iso-C 15 : 0 , anteiso-C 15 : 0 and iso-C 17 : 0 3-OH. Polar lipids of strain MT39 T included phosphatidylethanolamine, one unidentified aminolipid and four unidentified lipids. Menaquinone-6 was the only respiratory quinone in strain MT39 T . On the basis of the polyphasic data present in this study, strain MT39 T represents a novel species of the genus Salinimicrobium , for which the name Salinimicrobium profundisediminis sp. nov. is proposed, with type strain being MT39 T (=MCCC 1K07832 T =KCTC 92381 T ).

A Gram-straining-negative, facultatively anaerobic, motile by means of a polar flagellum and rod-shaped marine bacterium, designated S4M6 T , was isolated from surface seawater collected in Dongshan Bay (Fujian, PR China). Phylogenetic analysis based on 16S rRNA genes, phylogenomic analysis of single-copy gene families and whole genome data indicated that S4M6 T represented a member of the genus Vibrio . The closest phylogenetic relatives of S4M6 T were Vibrio marisflavi CGMCC 1.8994 T (97.8 % 16S rRNA gene sequence pairwise similarity), Vibrio variabilis LMG 25438 T (96.9 %), Vibrio gangliei SZDIS-1 T (96.2 %) and Vibrio aestivus M22 T (96.1 %). The growth of S4M6 T occurred at 15-35 °C (optimum 28 °C), pH 4.0-9.0 (optimum 5.0-7.0) and in the presence of 2-5 % (w/v) NaCl (optimum 3 %). The predominant fatty acids (>10 %) are C 16 : 0 , summed feature 3 (C 16 : 1 ω7 c and/or C 16 :   1 ω6c) and summed feature 8 (C 18 : 1 ω7 c and/or C 18 :   1 ω6 c ). The DNA G+C content of the assembled genomic sequences was 43.4 % for S4M6 T . Average nucleotide identity (ANI) values between S4M6 T and the reference species were lower than the threshold for species delineation (95-96 %); in silico DNA-DNA hybridization further indicated that S4M6 T had less than 70 % similarity to its relatives. On the basis of the polyphasic evidence, strain S4M6 T is proposed to represent a novel species of the genus Vibrio , for which the name Vibrio sinus sp. nov. is proposed. The type strain is S4M6 T (= KCTC 92312 T = MCCC 1K06167 T ).

Two Gram-stain-negative, oxidase-positive, facultative anaerobic and rod-shaped motile bacteria, designated strains ZSDZ34 and ZSDE26, were isolated from offshore surface seawater collected near Qingdao. Phylogenetic analysis based on 16S rRNA gene sequences placed ZSDE26 T and ZSDZ34 T within the genus Vibrio , family Vibrionaceae , class Gammaproteobacteria . Strain ZSDE26 T was most closely related to Vibrio gallaecicus VB 8.9 T with 97.3 % sequence similarity, whereas ZSDZ34 T was most closely related to Vibrio aestuarianus subsp. cardii DSM 109723 T with 97.8 % sequence similarity. Strain ZSDE26 T grew with 1-5 % (w/v) NaCl (optimum, 4 %), at 16-28 °C (optimum, 28 °C) and at pH 6.0-9.0 (optimum, pH 7.0). Growth of strain ZSDZ34 T occurred with 1-6 % (w/v) NaCl (optimum, 3 %), at 16-37 °C (optimum, 28 °C) and at pH 6.0-9.0 (optimum, pH 7.0). Both strains shared the same major fatty acid components (more than 10 % of total fatty acids) of summed feature 3 (C 16 : 1 ω 7 c and/or C 16 : 1 ω 6 c ), summed feature 8 (C 18 : 1 ω 7 c and/or C 18 : 1 contained a higher proportion of iso-C ω . The DNA G+C contents of strains ZSDE26 c ) and C 16 : 0 were 42.8 and 44.5 mol%, respectively. On the basis of the results of polyphasic analysis, ZSDE26 T contained a higher proportion of iso-C 16 : 0 . The DNA G+C contents of strains ZSDE26 T and ZSDZ34 T were 42.8 and 44.5 mol%, respectively. On the basis of the results of polyphasic analysis, ZSDE26 T and ZSDZ34 T are considered to represent novel species within the genus Vibrio , for which the names Vibrio amylolyticus sp. nov. (type strain, ZSDE26 T =KCTC 82890 T =MCCC 1K06290 T ) and Vibrio gelatinilyticus sp. nov. (type strain, ZSDZ34 T =KCTC 82888 T =MCCC 1K06292 T ) are proposed, respectively.

A Gram-stain-negative, aerobic, flagellated and rod-shaped bacterium, designated strain SM2107 T , was isolated from a deep-sea sediment sample collected from the Southwest Indian Ocean. Strain SM2107 T grew at 4-40 °C and with 0-10.0 % (w/v) NaCl. It reduced nitrate to nitrite and hydrolysed casein, gelatin, chitin and DNA. The phylogenetic trees based on the 16S rRNA genes and single-copy orthologous clusters showed that strain SM2107 T , together with Rheinheimera tuosuensis , Rheinheimera perlucida and Arsukibacterium ikkense , formed a separate clade, having the highest similarity to the type strain of Rheinheimera tuosuensis (98.3%). The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol and the major cellular fatty acids were summed feature 8 (C 18 : 1  ω 7 c and/or C 18 : 1  ω 6 c ), C 16 : 0 , C 17 : 1 ω 8 с and summed feature 3 (C 16 : 1 ). The only respiratory quinone was Q-8. The genomic DNA G+C content of strain SM2107  ω 7 c and type strains of 16 : 1  ω 6 c ). The only respiratory quinone was Q-8. The genomic DNA G+C content of strain SM2107 T was 48.8 %. The digital DNA-DNA hybridization values between strain SM2107 T and type strains of Rheinheimera tuosuensis , Rheinheimera perlucida and Arsukibacterium ikkense were 41.16, 37.70 and 31.80 %, while the average amino acid identity values between them were 87.59, 86.76 and 83.64 %, respectively. Based on the polyphasic evidence presented in this study, strain SM2107 T ). Moreover, the transfer of Arsukibacterium , for which the name Arsukibacterium indicum was proposed. The type strain is SM2107 T (=MCCC M24986 T =KCTC 82921 T ). Moreover, the transfer of Rheinheimera tuosuensis and Rheinheimera perlucida to the genus Arsukibacterium as Arsukibacterium tuosuense comb. nov. (type strain TS-T4 T =CGMCC 1.12461 T =JCM 19264 T ) and Arsukibacterium perlucidum comb. nov. (type strain BA131 T =LMG 23581 T =CIP 109200 T ) is also proposed.

A Gram-stain-negative, non-motile, facultatively anaerobic and non-flagellated marine bacterium, designated JC070 T was isolated from the Yongle Blue Hole in the South China Sea. The temperature, pH and NaCl ranges for growth of strain JC070 T were 4-37 °C (optimum, 16 °C), pH 6.0-9.0 (optimum, pH 7.0) and 1.0 -6.0% (w/v; optimum, 3.0%). The predominant isoprenoid quinone of strain JC070 T was identified as menaquinone-7. The dominant fatty acids (>10%) were iso-C 15:0 (59.6%) and iso-C 17:0 3-OH (17.2%). The major polar lipids were aminophospholipid, aminolipid, two unknown phospholipids and two unidentified lipids. The genomic DNA G+C content was determined to be 37.0 mol%. Based on the results of polyphasic analysis, a new species, named Marinifilum caeruleilacunae sp. nov., within the genus Marinifilum was proposed. The type strain is JC070 T (= JCM 39045 T =MCCC 1K03774 T ).

A Gram-stain-negative, heterotrophic, aerobic, non-motile, rod-shaped bacterial strain (GW1-59 T ) belonging to the genus Lysobacter was isolated from coastal sediment collected from the Chinese Great Wall Station, Antarctica. The strain was identified using a polyphasic taxonomic approach. The strain grew well on Reasoner's 2A media and could grow in the presence of 0-4 % (w/v) NaCl (optimum, 1 %), at pH 9.0-11.0 and at 15-37 °C (optimum, 30 °C). Strain GW1-59 T possessed ubiquinone-8 as the sole respiratory quinone. The major phospholipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major fatty acids were summed feature 9 (10-methyl C 16 : 0 and/or iso-C 17 : 1  ω 9 c ), iso-C 15 : 0 , iso-C 16 : 0 , iso-C 17 : 0 , C 16 : 0 and iso-C 11 : 0 3-OH. DNA-DNA relatedness with Lysobacter concretionis Ko07 T , the nearest phylogenetic relative (98.5 % 16S rRNA gene sequence similarity) was 23.4 % (21.1-25.9 %). The average nucleotide identity value between strain GW1-59 T and L. concretionis was 80.1 %. The physiological and biochemical results and low level of DNA-DNA relatedness suggested the phenotypic and genotypic differentiation of strain GW1-59 T was 80.1 %. The physiological and biochemical results and low level of DNA-DNA relatedness suggested the phenotypic and genotypic differentiation of strain GW1-59 T species. On the basis of phenotypic, phylogenetic and genotypic data, a novel species, Lysobacter species. On the basis of phenotypic, phylogenetic and genotypic data, a novel species, Lysobacter antarcticus sp. nov., is proposed. The type strain is GW1-59 T (=CCTCC AB 2019390 T =KCTC 72831 T ).

Two novel Gram-stain-negative, facultative anaerobic, non-flagellated, rod-shaped bacterial strains, designated MT13 T and MT32, were isolated from sediment samples collected from the Mariana Trench at a depth of 8300 m. The two strains grew at -2-30 °C (optimum, 25 °C), at pH 5.5-10.0 (optimum, pH 7.5-8.0) and with 0-15 % (w/v) NaCl (optimum, 3-6 %). They did not reduce nitrate to nitrite nor hydrolyse Tweens 40 and 80, aesculin, casein, starch and DNA. The genomic G+C contents of draft genomes of strain MT13 T and MT32 were 52.2 and 54.1 m ol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains MT13 T and MT32 were affiliated with the genus Halomonas , with the highest similarity to the type strain of Halomonas olivaria . The values of average nucleotide identity and in silico DNA-DNA hybridization between strain MT13 T and MT32, and between strain MT13 T and five closely related type strains of Halomonas species indicated that strains MT13 T and MT32 belonged to the same species, but represented a novel species in the genus of Halomonas . The major cellular fatty acids of strains MT13 T and MT32 were C 16 : 0 , summed feature 3(C 16 : 1  ω 7 c / ω 6 c ) and summed feature 8 (C 18 : 1  ω 7 c ). Major polar lipids of strains MT13 ω 6 c and MT32 represent a novel species of the genus T and MT32 included phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Ubiquinone-9 was the predominant respiratory quinone. Based on data from the present polyphasic study, strains MT13 T and MT32 represent a novel species of the genus Halomonas , for which the name Halomonas profundi sp. nov. is proposed. The type strain is MT13 T (=MCCC 1K06389 T =KCTC 82923 T ).

A Gram-stain-negative, non-motile, strictly aerobic, rod-shaped bacterium, with one polar flagellum and named D11R37 T , was isolated from coral culture seawater of Acropora digitifera . Strain D11R37 T grew with 0-6 % (w/v) NaCl (optimum, 0.5%), at 10-41 °C (optimum, 28 °C) and at pH 6.0-7.0 (optimum, 7.0). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain D11R37 T formed a lineage within the genus Flavobacterium , and it was distinct from the most closely related species Flavobacterium suzhouense XIN-1 T and Flavobacterium suaedae G16-7 T with 16S rRNA gene sequences similarities of 95.97% and 95.48 %. The major respiratory quinone was menaquinone-6. The polar lipids comprised one phosphatidylethanolamine, two aminolipids and one unknown polar lipid. The predominant fatty acids (more than 10 % of total fatty acids) were iso-C 15 : 0 (18.0%), iso-C 17 : 0 3-OH (11.9 %) and summed feature 3 (10.9 %). The DNA G+C content was 41.3 mol%. Based on polyphasic taxonomic data, strain D11R37 T is considered to represent a novel species within the genus Flavobacterium , for which the name Flavobacterium coralii sp. nov. is proposed. The type strain is D11R37 T (=KCTC 82968 T =MCCC 1K06440 T ).

A Gram-strain-negative, facultatively anaerobic, motile, rod-shaped and flagellated marine bacterium, designated SM6 T , was isolated from surface seawater collected in Daya Bay (Guangdong, China). Phylogenetic analysis based on 16S rRNA gene sequences, multilocus sequence analysis, phylogenomic analysis of single-copy gene families and whole genome data showed that strain SM6 T belonged to the genus Vibrio . The closest phylogenetic relatives of SM6 T were Vibrio plantisponsor MSSRF60 T (97.38 % 16S rRNA gene sequence pairwise similarity), Vibrio variabilis R-40492 T (97.27 %), Vibrio aestuarianus ATCC 35048 T (97.21 %) and Vibrio sagamiensis LC2-047 T (97.3 %). Growth of strain SM6 T occurred at 10-45 °C (optimum 30 °C), at pH 6.0-9.0 (optimum 6.0) and in the presence of 0-10 % (w/v) NaCl (optimum 3-8 %). The predominant fatty acids (>10 %) were summed feature 3 (C 16 : 1 ω 7 c or/and C 16 : 1 ω 6 c ), C 16 : 0 and summed feature 8 (C 18 : 1 ω ). The DNA G+C content of the assembled genomic sequences was 47.37 % for strain SM6 c or/and C 18 : 1 ω DNA-DNA hybridization further showed that the strains shared less than 70 % similarity. On the basis of evidence from the present polyphasic study, strain SM6 c is considered to represent a novel species of the genus T . Average nucleotide identity values between SM6 T and its reference species were lower than the threshold for species delineation (95-96 %); in silico DNA-DNA hybridization further showed that the strains shared less than 70 % similarity. On the basis of evidence from the present polyphasic study, strain SM6 T is considered to represent a novel species of the genus Vibrio , for which the name Vibrio agarilyticus sp. nov. is proposed. The type strain is SM6 T (=KCTC 82076 T =MCCC 1K04327 T ).

A Gram-stain-negative, aerobic, gliding, reddish-orange-coloured, rod-shaped strain, designated SR4 T , was isolated from surface seawater sampled at Luhuitou fringing reef (South China Sea). Phylogenetic analyses based on the 16S rRNA gene, phylogenomic analysis of single-copy gene families and whole genome data affiliated it to the genus Flammeovirga . It was most closely related to Flammeovirga yaeyamensis NBRC 100898 T (97.99 % 16S rRNA gene similarity). The genome average nucleotide identity and DNA-DNA relatedness values between strain SR4 T and its reference strains were less than 74.2 and 16.3 %, respectively. Growth occurred at 20-35 °C (optimum, 28 °C), pH 6.0-9.0 (optimum, pH 7.0) and in the presence of 1-6 % (w/v) NaCl (optimum, 2-4 %). The dominant fatty acids were C 16 : 0 , iso-C 15 : 0 and C 20 : 4  ω . The polar lipid profile of strain SR4 c comprised phosphatidylethanolamine, two glycolipids, two aminophospholipids and three unidentified lipids. The major respiratory quinone was MK-7. The DNA G+C content of strain SR4 T was 34.20 mol%. On the basis of the polyphasic evidence, strain SR4 T is proposed as representing a novel species of the genus T is proposed as representing a novel species of the genus Flammeovirga , for which the name Flammeovirga agarivorans sp. nov. is proposed. The type strain is SR4 T (=KCTC 82075 T =MCCC 1A17137 T ).

A Gram-stain-negative, aerobic, ovoid-rod-shaped bacterium, designated strain SM1903 T , was isolated from surface seawater of the Mariana Trench. The strain grew at 15-37 °C (optimum, 35 °C) and with 1-15 % (optimum, 4 %) NaCl. It hydrolysed aesculin but did not reduce nitrate to nitrite and hydrolyse Tween 80. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain SM1903 T formed a separate lineage within the family Rhodobacteraceae , sharing the highest 16S rRNA gene sequence similarity with type strains of Pseudooceanicola antarcticus (95.7 %) and Roseisalinus antarcticus (95.7 %). In phylogenetic trees based on single-copy OCs and whole proteins sequences, strain SM1903 T fell within a sub-cluster encompassed by Oceanicola granulosus , Roseisalinus antarcticus and Histidinibacterium lentulum and formed a branch adjacent to Oceanicola granulosus . The major cellular fatty acids were summed feature 8 (C 18 : 1  ω 7 c and/or C 18 : 1  ω 6 c ), C 16 : 0 . The polar lipids mainly comprised phosphatidylglycerol, phosphatidylcholine, one unidentified lipid, one unidentified aminolipid, and one unidentified glycolipid. The solo respiratory quinone was ubiquinone-10. The genomic DNA G+C content of strain SM1903 18 : 1 was 66.0 mol%. Based on the results of phenotypic, chemotaxonomic, and phylogenetic characterization for strain SM1903  ω , it is considered to represent a novel species of a novel genus in the family c . The polar lipids mainly comprised phosphatidylglycerol, phosphatidylcholine, one unidentified lipid, one unidentified aminolipid, and one unidentified glycolipid. The solo respiratory quinone was ubiquinone-10. The genomic DNA G+C content of strain SM1903 T was 66.0 mol%. Based on the results of phenotypic, chemotaxonomic, and phylogenetic characterization for strain SM1903 T , it is considered to represent a novel species of a novel genus in the family Rhodobacteraceae , for which the name Pelagovum pacificum gen. nov., sp. nov. is proposed. The type strain is SM1903 T (=MCCC 1K03608 T =KCTC 72046 T ).

A Gram-stain-negative, strictly aerobic, motile by gliding, rod-shaped and non-flagellated marine bacterium strain, designated BOM4 T , was isolated from a mussel inhabiting the Tangyin hydrothermal field of the Okinawa Trough. The growth temperature was in the range of 16-40 °C, and the optimum temperature was 37 °C. Optimal growth occurred at pH 7.0 and in the presence of 1 % (w/v) NaCl. The predominant isoprenoid quinone of strain BOM4 T was identified as menaquinone-6 (MK-6). The predominant fatty acids (>10 %) were iso-C 15 : 0 (43.8 %) and iso-C 17 : 0 3-OH (17.5 %). The major polar lipids comprised one phosphatidylethanolamine, three unidentified aminolipids and two unidentified lipids. Based on 16S rRNA gene sequence analyses, strain BOM4 T was found to be most closely related to Gramella aestuarii JCM 17790 T (96.7 %), followed by Gramella flava JLT2011 T (96.1 %), Gramella sediminilitoris GHTF-27 T (95.6 %) and Gramella gaetbulicola RA5-111 T (95.5 %) and with lower sequence similarities (93.7- 95.4 %) to other species of the genus Gramella . Genome relatedness between strain BOM4 T and G. aestuarii JCM 17790 T was computed using both average nucleotide identity and DNA-DNA hybridization with values of 75.6 and 19.3±2.4 %, respectively. The DNA G+C content of strain BOM4 T was 41.4 mol%. On the basis of polyphasic analysis, strain BOM4 T was considered to represent a novel species of the genus Gramella , for which the name Gramella bathymodioli sp. nov. is proposed. The type strain is BOM4 T (=MCCC 1K03735 T =JCM 33424 T ).

A Gram-stain-negative, aerobic, polarly flagellated, straight or curved rod-shaped bacterium, designated strain M1K-6 T , was isolated from deep seawater samples collected from the Mariana Trench. The strain grew at -4 to 37 °C (optimum, 25-30 °C), at pH 5.5-10.0 (optimum, pH 7.0) and with 0.5-14.0  % (w/v) NaCl (optimum, 2.0 %). It did not reduce nitrate to nitrite nor hydrolyse gelatin or starch. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain M1K-6 T was affiliated with the genus Marinomonas , sharing 93.1-97.0  % sequence similarity with the type strains of recognized Marinomonas species. The major cellular fatty acids were summed feature 3 (C 16 : 1 ω 6 c /C 16 : 1 ω 7 c ), summed feature 8 (C 18 : 1 ω 7 c /C 18 : 1 ω . The predominant respiratory quinone was ubiquinone-8. Polar lipids of strain M1K-6 c included phosphatidylethanolamine, phosphatidylglycerol and two unidentified lipids. The genomic G+C content of strain M1K-6 16 : 0 , C 10 : 0 3-OH and C 18 : 0 . The predominant respiratory quinone was ubiquinone-8. Polar lipids of strain M1K-6 T included phosphatidylethanolamine, phosphatidylglycerol and two unidentified lipids. The genomic G+C content of strain M1K-6 T was 46.0 mol%. Based on data from the present polyphasic study, strain M1K-6 T was considered to represent a novel species within the genus Marinomonas , for which the name Marinomonas profundi sp. nov. is proposed. The type strain is M1K-6 T (=KCTC 72501 T =MCCC 1K03890 T ).

A Gram-stain-negative, oxidase- and catalase-positive, facultative anaerobic and rod-shaped bacterium, designated strain SM1977 T , was isolated from the surface of coralline algae collected from the intertidal zone at Qingdao, PR China. The strain grew at 10-35 °C, pH 4.5-8.5 and with 1-8.5% (w/v) NaCl. It reduced nitrate to nitrite and hydrolysed Tween 20 and DNA. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1977 T was affiliated with the genus Vibrio , having the highest sequence similarity (97.6 %) to the type strain of Vibrio casei , followed by those of another five species (95.6-97.6 %) in the Rumoiensis clade of the genus Vibrio . However, the in silico DNA-DNA hybridization (75.3-75.9 %) and average nucleotide identity (21.6-22.8 %) values of SM1977 T against these close relatives were all below the corresponding thresholds to discriminate bacterial species. The major fatty acids were summed feature 3 (C 16:1  ω 7 c and/or C 16:1  ω 6 c ), C 16:0 and summed feature 8 (C 18:1  ω ). The predominant polar lipids were phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The sole respiratory quinone was Q-8. The genomic DNA G+C content of strain SM1977 c , determined from the obtained whole genomic sequence, was 42.3 mol%. On the basis of the polyphasic results obtained in this study, strain SM1977 18:1  ω 7 c ). The predominant polar lipids were phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The sole respiratory quinone was Q-8. The genomic DNA G+C content of strain SM1977 T , determined from the obtained whole genomic sequence, was 42.3 mol%. On the basis of the polyphasic results obtained in this study, strain SM1977 T is considered to represent a novel species within the genus Vibrio , for which the name Vibrio algicola sp. nov. is proposed. The type strain is SM1977 T (=MCCC 1K04351 T =KCTC 72847 T ).

A Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacterium, designated ZYF650 T , was isolated from the hadal seawater (9600 m) of the Mariana Trench. Results of phylogenetic analysis based on 16S rRNA gene sequences indicated that ZYF650 T formed a lineage within the family Alteromonadaceae that was distinct from the most closely related species Marinobacter mobilis and Marinobacter nitratireducens with 16S rRNA gene sequences similarities of 98.0 and 97.7 %, respectively. Strain ZYF650 T showed average nucleotide identity values of 75.7 % with Marinobacter hydrocarbonoclasticus , 73.3 % with Marinobacter mobilis and 79.3 % with Marinobacter nitratireducens , and DNA-DNAhybridization values of 21.5, 21.3 and 22.0 % with M. hydrocarbonoclasticus , M. mobilis and M. nitratireducens , respectively, which were lower than the threshold for species delineation. Strain ZYF650 T grew with 0-14 % (w/v) NaCl (optimum, 7-8 %) at a temperature range of 10-45 °C (optimum, 28 °C) and pH 6.0-9.5 (optimum, pH 7.0-8.0). The sole respiratory quinone was ubiquinone-9 (Q-9). The polar lipids in ZYF650 T comprised phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, three unidentified polar lipids, two unidentified aminolipids and two phospholipids. The predominant fatty acids (more than 10 % of total fatty acids) were C 18 : 1  ω9 c (21.9 %), C 16 : 0 (21.7 %), C 12 : 0 3-OH (14.0 %), C 16 : 1  ω9 c (13.2 %) and C 12 : 0 (12.2 %). The DNA G+C content of strain ZYF650 T was 55.6 %. On the basis of polyphasic taxonomic analysis, strain ZY650 T is considered to represent a novel specie of the genus Marinobacter in the family Alteromonadaceae , for which the name Marinobacter salinexigens sp. nov. is proposed. The type strain is ZYF650 T (=JCM 33013 T =MCCC 1K03552 T ).

A Gram-stain-negative, aerobic, non-flagellated and rod- or ovoid-shaped bacterium, designated as strain S4J41 T , was isolated from Antarctic intertidal sediment. The isolate grew at 0-37 °C and with 0.5-10 % (w/v) NaCl. It reduced nitrate to nitrite and hydrolysed Tween 80 and gelatin. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain S4J41 T constituted a distinct phylogenetic line within the family Rhodobacteraceae and was closely related with some species in the genera Ruegeria , Phaeobacter , Pseudopuniceibacterium , Sulfitobacter , Puniceibacterium and Poseidonocella with 98.6-95.7 % 16S rRNA gene sequence similarities. The major cellular fatty acids were C 16 : 0 , summed feature 8 (C 18 : 1   ω7 c and/or C 18 : 1   and the major polar lipids were phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, phosphatidylethanolamine and one unidentified aminolipid. The sole respiratory quinone was Q-10. The genomic DNA G+C content of strain S4J41 c ) and C 18 : 0 and the major polar lipids were phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, phosphatidylethanolamine and one unidentified aminolipid. The sole respiratory quinone was Q-10. The genomic DNA G+C content of strain S4J41 T was 60.3 mol%. Based on the phylogenetic, chemotaxonomic and phenotypic data obtained in this study, strain S4J41 T is considered to represent a novel species in a new genus within the family Rhodobacteraceae , for which the name Antarcticimicrobium sediminis gen. nov., sp. nov. is proposed. The type strain is S4J41 T ). Moreover, the transfer of T =KCTC 62793 T ). Moreover, the transfer of Ruegeria lutea Kim et al . 2019 to Antarcticimicrobium gen. nov. as Antarcticimicrobium luteum comb. nov. (type strain 318-1 T =JCM 30927 T =KCTC 72105 T ) is also proposed.

A Gram-stain-negative, obligately anaerobic, non-motile, non-spore-forming, long-rod-shaped and non-flagellated bacterial strain, designated T3-2 S1-C T , was isolated from a sediment sample collected at the Okinawa Trough. Phylogenetic analyses of 16S rRNA gene sequences and the whole genome revealed that strain T3-2 S1-C T was a member of the family Marinifilaceae and exhibited less than 95.1 % sequence similarities to the closely related type strains of the family Marinifilaceae . Optimal growth occurred at pH 7.0, 28 °C and in the presence of 3 % (w/v) NaCl. The isoprenoid quinone of strain T3-2 S1-C T was identified as menaquinone-7 (MK-7) and the predominant fatty acids (>10 %) were iso-C 15 : 0 (38.9 %) and anteiso-C 15 : 0 (11.6 %). The major polar lipids were one phosphatidylethanolamine, one phosphatidylmonomethylethanolamine, one aminolipids, two unidentified lipids and two unidentified phospholipids. The DNA G+C content of strain T3-2 S1-C T was 35.7 mol%. On the basis of the results of polyphasic analyses, strain T3-2 S1-C T is considered to represent a novel species of the genus Ancylomarina , for which the name Ancylomarina longa sp. nov. is proposed. The type strain is T3-2 S1-C T (=KCTC 15505 T =MCCC 1K01617 T ).

Blue holes are unique geomorphological units characterized by steep redox and biogeochemical gradients. Yongle Blue Hole is located on the largest atoll (Yongle Atoll) of the western Xisha Islands in the South China Sea. A Gram-stain-negative, facultatively anaerobic, non-motile, non-flagellated marine bacterium with creamy white colonies, designated JC036 T , was isolated from Yongle Blue Hole. Cells were short-rod-shaped and catalase-negative. 16S rRNA gene sequence analysis showed that sequence similarities were lower than 91.6 % against all validly named species in the family Prolixibacteraceae ; a reconstructed phylogenetic tree indicated that strain JC036 T formed a lineage with strains in the family Prolixibacteraceae . Growth occurred at 4-37 °C (optimum, 28 °C), at pH 5.0-9.0 (optimum, 7.0) and in the presence of 2-6 % (w/v) NaCl (optimum, 3 %). The prevalent isoprenoid quinone of strain JC036 T was menaquinone-7 (MK-7). Iso-C 15 : 0 and iso-C 17 : 0 3-OH were the predominant fatty acids. The major polar lipids included a phospholipid, phosphatidylethanolamine, an aminophospholipid and four unidentified lipids. The genomic DNA G+C content of strain JC036 T was 37.8 mol%. Based on physiological and biochemical characteristics and whole genome comparisons, we propose a new genus and species, Puteibacter caeruleilacunae gen. nov., sp. nov., within the family Prolixibacteraceae . The type strain of Puteibacter caeruleilacunae is JC036 T (=JCM 33128 T =MCCC 1K03579 T ). From this study, a deeper understanding of the community of the microorganism and their roles in biogeochemical cycles, especially anaerobic bacteria, is provided.

A Gram-stain-negative, strictly aerobic, oval-shaped, non-motile bacterium with no flagella, designated strain SCR17 T , was isolated from a shrimp gill habitat in Tangyin hydrothermal field of Okinawa Trough. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SCR17 T formed a lineage within the family ' Rhodobacteraceae ', and shared 16S rRNA gene sequence similarity of 93.2-96.2 % to the related genera Aquicoccus and Roseivivax . Strain SCR17 T was able to grow with 0-14 % (w/v) NaCl (optimum, 9-10 %). The sole respiratory quinone was ubiquinone-10. The major polar lipids of strain SCR17 T comprised phosphatidylcholine (PC), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), an unidentified aminolipid (AL), an unidentified phospholipid (PL) and an unidentified lipid (L). The predominant fatty acids (more than 10 % of the total fatty acids) were C 18 : 1 ω7 c or/and C 18 : 1 ω6 c , anteiso-C 15 : 0 , C 16 : 0 and C 19 : 0 cyclo ω 8 c . The genomic DNA G+C content of strain SCR17 T was 67.7 mol%. Based on polyphasic taxonomic analyses, strain SCR17 T is considered to represent a novel species in a new genus of the family ' Rhodobacteraceae ', for which the name Carideicomes alvinocaridis gen. nov., sp. nov. is proposed. The type strain of Carideicomes alvinocaridis is SCR17 T (=JCM 33426 T =MCCC 1K03732 T ). The discovery of a novel host-associated bacterium in hydrothermal fields provides an opportunity for the study of host-bacterial symbiosis in extreme environments.

A Gram-stain-negative, facultatively anaerobic, flagellated and rod-shaped bacterium, designated strain SM1901 T , was isolated from a brown algal sample collected from Kings Bay, Svalbard, Arctic. Strain SM1901 T grew at -4‒30 °C and with 0-7.0 % (w/v) NaCl. It reduced nitrate to nitrite and hydrolysed DNA and Tween 80. Results of phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SM1901 T was affiliated with the genus Shewanella , showing the highest sequence similarity to the type strain of Shewanella litoralis (97.5%), followed by those of Shewanella vesiculosa , Shewanella livingstonensis and Shewanella saliphila (97.3 % for all three). The major cellular fatty acids were summed feature 3 (C 16 : 1 ω 7 с and/or C 16 : 1 ω 6 с ), C 16 : 0 , C 18 : 0 , iso-C 15 : 0 and the major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. The respiratory quinones were ubiquinones Q-7, Q-8, menaquinones MK-7(H) and MK-8. The genome of strain SM1901 17 : 1 was 4648537 nucleotides long and encoded a variety of cold adaptation related genes, providing clues for better understanding the ecological adaptation mechanisms of polar bacteria. The genomic DNA G+C content of strain SM1901 ω 8 с was considered to represent a novel species, constituting a novel psychrotolerant lineage out of the known SF clade encompassed by polar T was 4648537 nucleotides long and encoded a variety of cold adaptation related genes, providing clues for better understanding the ecological adaptation mechanisms of polar bacteria. The genomic DNA G+C content of strain SM1901 T was 40.5 mol%. Based on the polyphasic evidence presented in this paper, strain SM1901 T was considered to represent a novel species, constituting a novel psychrotolerant lineage out of the known SF clade encompassed by polar Shewanella species, within the genus Shewanella , for which the name Shewanella polaris sp. nov. is proposed. The type strain is SM1901 T (=KCTC 72047 T =MCCC 1K03585 T ).

A Gram-stain-negative, strictly aerobic, non-motile, long, straight-rod and non-flagellated marine bacterium strain, designated SCR12 T , was isolated from the gill of a shrimp collected in the Tangyin hydrothermal field of the Okinawa Trough. The growth temperature was in the range of 16-40 °C and the optimum temperature was 37 °C. Optimal growth occurred at pH 6.5 and in the presence of 3 % (w/v) NaCl. The predominant isoprenoid quinone of strain SCR12 T was menaquinone-6 (MK-6). The predominant fatty acids (>10 %) were iso-C 15 : 0 (44.2 %), iso-C 15 : 1 G (19.0 %) and iso-C 17 : 0 3-OH (12.1 %). The major polar lipids comprised one phosphatidylethanolamine, three unidentified phospholipids, two unidentified aminolipids and three unidentified lipids. Based on the results of 16S rRNA gene sequence analysis, strain SCR12 T was found to be most closely related to Muricauda olearia CL-SS4 T (98.09 %), followed by Muricauda beolgyonensis BB-My12 T (97.65 %), Muricauda aquimarina SW-63 T (97.58 %) and Muricauda ruestringensis DSM 13258 T (97.31 %) and with lower sequence similarities (95.74-97.10 %) to other species of the genus Muricauda . Genome relatedness between strain SCR12 T and M. olearia CL-SS4 T was computed using both average nucleotide identity (ANI) and DNA-DNA hybridization (DDH) and resulted in values of 85.6 % and 29.3±2.3 %, respectively. The genomic DNA G+C content of strain SCR12 T was 42.3 mol%. On the basis of polyphasic analysis, the strain SCR12 T was considered to represent a novel species of the genus Muricauda, for which the name Muricauda alvinocaridis sp. nov. is proposed. The type strain is SCR12 T (=MCCC 1K03731 T =JCM 33425 T ).

Two Gram-staining-negative, facultatively anaerobic, motile, short clavate and flagellated marine bacteria, designated strains BEI233 T and LJC006 T , were isolated from the East China Sea. On the basis of the results of 16S rRNA gene sequencing and multilocus sequence analysis, BEI233 T and LJC006 T should be assigned to the genus Vibrio . The closest phylogenetic relatives of BEI233 T are Vibrio scophthalmi LMG 19158 T (98.7 % 16S rRNA gene sequence pairwise similarity), Vibrio ichthyoenteri DSM 14397 T (98.5 %), Vibrio renipiscarius KCTC 42287 T (97.7 %), Vibrio aestuarianus ATCC 35048 T (97.3 %) and Vibrio thalassae MD16 T (96.5 %), whereas for LJC006 T they were Vibrio furnissii CAIM 518 T (97.1 %), Vibrio fluvialis LMG 7894 T (97.0%), Vibrio tritonius JCM 16456 T (96.9 %) and Vibrio xuii LMG 21346 T (96.1 %). The growth of BEI233 T occurred at 10-37 °C, pH 5.0-8.0 and with 1-7 % (w/v) NaCl, while the growth of LJC006 T occurred at 10-37 °C, pH 6.0-9.0, and 0-8 % (w/v) NaCl. The predominant fatty acids (>10 %) were summed feature 3 (C 16 : 1 ω7 c or/and C 16 : 1 ω6 c ), C 16 : 0 and summed feature 8 (C 18 : 1 ω7 c or/and C 18 : 1 ω6 c ), with different proportions. The DNA G+C contents of BEI233 T and LJC006 T are 42.41 mol% and 41.88 mol%, respectively. On the basis of the results of polyphasic analysis, BEI233 T and LJC006 T are considered to represent novel species of the genus Vibrio, for which the names Vibrio sinensis sp. nov. and Vibrio viridaestus sp. nov. are proposed. The type strains are BEI233 T (=JCM 32692 T =KCTC 62618 T ) and LJC006 T (=JCM 32693 T =KCTC 62620 T ), respectively.

A Gram-stain-negative, strictly aerobic, rod-shaped bacterium, without flagellum and designated ZYF765 T , was isolated from seawater sampled at a depth of 4000 m in the Mariana Trench. Strain ZYF765 T grew with 1-15 % (w/v) NaCl (optimum, 4 %), at 16-37 °C (28 °C) and at pH 6.0-10.0 (pH 7.0-8.0). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain ZYF765 T formed a lineage within the family Hyphomonadaceae , and was distinct from the most closely related species Glycocaulis abyssi , Glycocaulis albus and Glycocaulis alkaliphilus with 16S rRNA gene sequences similarities ranging from 98.42 to 98.63 %. The major respiratory quinone was ubiquinone-10 (Q-10). The polar lipids comprised three unidentified glycolipids, one unidentified aminophospholipid, one unidentified phospholipid and one unidentified aminolipid. The predominant fatty acids (more than 10 % of total fatty acids) were C 18 : 1 ω7 c (46.2 %) and C 18 : 0 (14.1 %). The DNA G+C content was 67.7 mol%. On the basis of the results of polyphasic taxonomic analysis, strain ZYF765 T is considered to represent a novel species within the genus Glycocaulis , for which the name Glycocaulis profundi sp. nov. is proposed. The type strain is ZYF765 T (=JCM 33028 T =MCCC 1K03554 T ).

A Gram-negative, aerobic, non-flagellated and ovoid- or rod-shaped bacterium, designated strain SM1902 T , was isolated from the sediment sampled at the Jia River estuary, Yantai, PR China. The strain grew at 10-37 °C (optimum, 25-30 °C), pH 6.0-10.0 (pH 7.0) and with 0.5-13.0 % (w/v) NaCl (2.5%). It reduced nitrate to nitrite, but did not produce bacteriochlorophyll a . The results of phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1902 T constituted a separated lineage within the family Rhodobacteraceae and was closely related to Meridianimarinicoccus roseus TG-679 T and Phycocomes zhengii LMIT002 T with 96.1 and 94.3 % 16S rRNA gene sequence similarities, respectively. The predominant cellular fatty acid was summed feature 8 (C 18 : 1 ω7 c and/or C 18 : 1 ω6 c ). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, an unidentified aminolipid and an unidentified lipid. The sole respiratory quinone was ubiquinone-10. The in silico DNA-DNA hybridization values between strain SM1902 T and Meridianimarinicoccus roseus TG-679 T and Phycocomes zhengii LMIT002 T were 19.6 and 19.5 %, respectively; and the average nucleotide identity values between them were 76.1 and 74.2 %, respectively. The genomic DNA G+C content of strain SM1902 T was 58.2 mol%. Based on the phylogenetic, chemotaxonomic and phenotypic data obtained in this study, strain SM1902 T is considered to represent a novel species in a new genus within the family Rhodobacteraceae , for which the name Fluviibacterium aquatile gen. nov., sp. nov. is proposed. The type strain is SM1902 T (=KCTC 72045 T =MCCC 1K03596 T =CCTCC AB 2018346 T ).

A Gram-stain-negative, pink-pigmented, rod-shaped, non-flagellated, aerobic bacterium, designated strain SM1701 T , was isolated from a rotten seaweed collected off Fildes Peninsula, King George Island, West Antarctica. The strain grew at 4-30 °C, pH 6.0-8.0 and with 0.5-5 % (w/v) NaCl. It hydrolysed gelatin and Tweens (40, 60 and 80), but did not reduce nitrates to nitrites. The major cellular fatty acids of strain SM1701 T were iso-C 15 : 0 , iso-C 15 : 1 G, iso-C 16 : 1 G, C 16 : 0 and iso-C 17 : 0 3-OH. Polar lipids included phosphatidylethanolamine, one unidentified aminolipid, two unidentified glycolipids and one unidentified aminoglycolipid. The major respiratory quinone was MK-7. The genomic DNA G+C content of strain SM1701 T was 34.1 mol%. It showed high 16S rRNA gene sequence similarities to Crocinitomix algicola (93.8 %) and Crocinitomix catalasitica (92.5 %) and less than 91 % sequence similarities to other known members in the family Crocinitomicaceae . Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain SM1701 T constituted a distinct lineage within the family Crocinitomicaceae . The phylogenetic trees based on concatenated 261 protein sequences from genome sequences showed that strain SM1701 T occupied a branch separated from those of known genera in the family of Crocinitomicaceae , indicating it may belong to a new genus. On the basis of the polyphasic characterization of strain SM1701 T in this study, it is considered to represent a novel species in a new genus in the family Crocinitomicaceae , for which the name Putridiphycobacter roseus gen. nov., sp. nov. is proposed. The type strain is SM1701 T (=KCTC 62302 T =NBRC 113201 T =CGMCC 1.16510 T ).

Two Gram-stain-negative, catalase- and oxidase-positive, facultative anaerobic and rod-shaped motile bacteria, designated strains BEI176 T and BEI207 T , were isolated from seawater collected in the East China Sea. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains BEI176 T and BEI207 T belonged to the genus Vibrio and were closely related to each other with 98.18 % similarity. The closest phylogenetic relatives of strain BEI176 T were Vibrio alginolyticus LMG 4409 T (98.85 %) and Vibrio campbellii LMG 11216 T (98.81 %), whereas the closest relative of strain BEI207 T was Vibrio hepatarius LMG 20362 T (98.64 %). The two strains showed growth at different conditions; while strain BEI176 T grew at 16-37 °C, pH 5.0-9.5 and 0-7.0 % (w/v) NaCl, the growth of strain BEI207 T occurred at 10-37 °C, pH 6.0-9.5 and 1.0-7.0 % (w/v) NaCl. Both strains shared the same major fatty acid components of summed feature 3 (C 16 : 1 ω7 c or C 16 : 1 ω6 c ), C 16 : 0 and summed feature 8 (C 18 : 1 ω6 c or C 18 : 1 ω7 c ). The DNA G+C contents of the assembled genomic sequences were 44.73 and 45.06 mol% for strains BEI176 T and BEI207 T , respectively. Average nucleotide identity values between the two strains and their reference species were lower than the threshold for species delineation (95-96 %); in silico DNA-DNA hybridization further showed that the two strains had less than 70 % similarity to their relatives. Therefore, two novel Vibrio species are proposed to accommodate them: Vibrioouci sp. nov. (type strain, BEI176 T =MCCC 1K03515 T =JCM 32690 T = KCTC 62616 T ) and Vibrioaquaticus sp. nov. (type strain, BEI207 T =MCCC 1K03516 T =JCM 32691 T =KCTC 62617 T ).

A Gram-staining-negative, strictly aerobic, long-rod shaped with no flagellum and yellow-pigmented bacterium designated strain ZXX205 T , was isolated from the hadal seawater at the depth of 7500 m in the Mariana Trench, Pacific Ocean. Phylogenetic analysis based on 16S rRNA gene sequences placed strain ZXX205 T within the genus Winogradskyella and strain ZXX205 T was most closely related to Winogradskyella flava KCTC 52348 T and Winogradskyella echinorum KCTC 22026 T with 96.9 % and 96.6 % sequence similarity, respectively. The sequence similarities to all other type strains were 96.3 % or less, and to the type strain Winogradskyella thalassocola LMG 22492 T was 94.1 %. Growth occurred in the presence of 0-9.0 % (w/v) NaCl (optimum 3.0 %), at 4-45 °C (optimum 28 °C) and pH 6.0-9.0 (optimum pH 7.5). The sole respiratory quinone was menaquinone 6 (MK-6). The dominant cellular fatty acids (>10 %) of strain ZXX205 T were iso-C 15 : 0 , iso-C 15 : 1 G, iso-C 16 : 0 3-OH and iso-C 16 : 0 . The polar lipids profile contained predominantly phosphatidylethanolamine, four glycolipids, four unidentified aminolipids and three unidentified lipids. The genomic DNA G+C content was 35.5 %. The DNA-DNA relatedness (DDH) values between strain ZXX205 T and the most closely related species Winogradskyella flava and Winogradskyella echinorum were 21.1 and 20.4 %, respectively. Based on polyphasic taxonomic analysis, strain ZXX205 T is considered to represent a novel species in the genus Winogradskyella of the family Flavobacteriaceae , for which the name Winogradskyella ouciana is proposed. The type strain is ZXX205 T (=MCCC 1K03851 T =JCM 33665 T ).

Two Gram-stain-negative, aerobic, rod-shaped bacteria, polar flagellated, designated strains SM2066 T and SM1966 T , were respectively isolated from the surfaces of Colpomenia sinuosa and Ulva pertusa macroalgae collected off the coastal areas of Rongcheng, PR China. Strain SM2066 T grew at 8-37 °C and with 0.5-7.0 % (w/v) NaCl, while strain SM1966 T grew at 5-30 °C and with 0.5-8.5% (w/v) NaCl. Both of them reduced nitrate to nitrite and required Na + for growth but neither of them hydrolysed starch and DNA. Phylogenetic analysis based on 16S rRNA gene and single-copy orthologous cluster sequences revealed that both strains SM2066 T and SM1966 T were affiliated with the genus Marinomonas but formed distinct phylogenetic branches from known Marinomonas species, respectively sharing the highest 16S rRNA gene sequence similarities with type strains of Marinomonas ushuaiensis (97.9 %) and Marinomonas blandensis (96.7 %). The digital DNA-DNA hybridization and average nucleotide identity values between strains SM2066 T and SM1966 T and type strains of closely related Marinomonas species were all below 22.9 and 79.9 mol%, respectively. The major fatty acids of the two strains were summed feature 3 (C 16 : 1  ω 6 c /C 16 : 1  ω 7 c ), summed feature 8 (C 18 : 1 , with their predominant polar lipids being phosphatidylethanolamine and phosphatidylglycerol, and their sole respiratory quinone being Q-8. The genomic DNA G+C contents of strains SM2066  ω 7 c determined from genomic sequences were 40.3 and 41.6 mol%, respectively. On the basis of the polyphasic evidence presented in this study, strains SM2066 16 : 0 , with their predominant polar lipids being phosphatidylethanolamine and phosphatidylglycerol, and their sole respiratory quinone being Q-8. The genomic DNA G+C contents of strains SM2066 T and SM1966 T determined from genomic sequences were 40.3 and 41.6 mol%, respectively. On the basis of the polyphasic evidence presented in this study, strains SM2066 T and SM1966 T are considered to represent two novel species within the genus Marinomonas , for which the names Marinomonas colpomeniae sp. nov. and Marinomonas algicola sp. nov. are proposed. The type strains are SM2066 T (=MCCC 1K04390 T = KCTC 82372 T ) and SM1966 T (=MCCC 1K04387 T = KCTC 72848 T ), respectively.

A Gram-stain-negative, aerobic, non-spore-forming, rod-shaped, non-motile, yellow-pigmented bacteria, designated strain G5-32 T , belonging to the genus Kaistella was isolated from soil collected in the Antarctic. The strain was identified using a polyphasic taxonomic approach. The strain grew in the presence of 0-5% (w/v) NaCl (optimum, 1%), at pH 6.0-9.0 (optimum, pH 8.0) and at 4-28 °C (optimum, 20 °C). The predominant menaquinone was MK-6 (99.4%). The major fatty acids were anteiso-C 15:0 (28.2%), iso-C 15:0 (16.4%), summed feature 9 (comprising iso-C 17:1 ω 9 c and/or 10-methyl C 16:0 ; 10.6%) and iso-C 16:0 (5.9%). A phylogenetic tree based on 16S rRNA gene sequences showed that strain G5-32 T formed a lineage within the genus Kaistella with the closest phylogenetic neighbours Kaistella yonginensis HMD1043 T , Kaistella chaponensis DSM 23145 T , Kaistella jeonii DSM 17048 T and Kaistella carnis NCTC 13525 T (97.9, 97.8, 97.8 and 98.0 % 16S rRNA gene sequence similarity, respectively). The ANI values between strain G5-32 T and K. jeonii DSM 17048 T , K. chaponensis DSM 23145 T , K. carnis NCTC 13525 T and K. yonginensis were 90.9, 82.6, 77.1 and 76.3%. Concurrently, digital DNA-DNA hybridization values of strain G5-32 T were 90.9, 82.6, 77.1 and 76.3%. Concurrently, digital DNA-DNA hybridization values of strain G5-32 T assessed against K. jeonii DSM 17048 T , K. chaponensis DSM 23145 T , K. carnis NCTC 13525 T and K. yonginensis HMD1043 T were 42.3, 25.9, 21.7 and 21.3%, respectively. Based on phenotypic, phylogenetic and genotypic data, a novel species, Kaistella gelatinilytica sp. nov., is proposed. The type strain is G5-32 T (=CCTCC AA 2019083 T =KCTC 72766 T ).

A Gram-stain-negative, facultative aerobic, motile by a polar flagellum, rod-shaped strain, designated BEI247 T , was isolated from seawater at the bottom of the East China Sea. Phylogenetic analysis of the 16S rRNA gene and whole genome data affiliated it with the genus Photobacterium. It was most closely related to Photobacterium alginatilyticum P03D4 T (97.36 % 16S rRNA gene similarity). Multi-locus sequence analysis (MLSA) revealed a distinct lineage with P. alginatilyticum P03D4 T as its closest relative. Strain BEI247 T was found to have lower than 86.0 % similarities to the type strains of its most closely related species in MLSA, less than 82.3 % using genome average nucleotide identities, and less than 25.3 % in DNA-DNA relatedness studies. Growth occurred at 10-37 °C (optimum, 24 °C), pH 5.0-8.0 (pH 7.0) and in the presence of 1-5 % (w/v) NaCl (3 %). The dominant fatty acids were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The polar lipids of strain BEI247 T comprised phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, two phospholipids and one unknown lipid. The major respiratory quinone was ubiquinone-8 (Q-8). The DNA G+C content of strain BEI247 T was 46.45 mol%. On the basis of the polyphasic evidence, strain BEI247 T is proposed as representing a novel species of the genus Photobacterium, for which the name Photobacterium chitinilyticum sp. nov. is proposed. The type strain is BEI247 T (=JCM 32689 T =MCCC 1K03517 T =KCTC 62619 T ).

A novel Gram-stain-negative, strictly aerobic, rod-shaped motile bacterium with a single flagellum, designated strain WRAS1 T , was isolated from deep seawater of the Okinawa Trough. Growth occurred in the presence of 0.0-9.0 % NaCl (w/v; optimum, 3.0-4.0 %), at 4-45 °C (optimum, 28-37 °C) and pH 7.0-10.0 (optimum, pH 7.0-8.0). The major fatty acid (>10 % of total fatty acids) was summed feature 8, comprising C18:1ω6c and/or C18:1ω7c. The major polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine and three unidentified lipids. The major respiratory quinone was ubiquinone-10. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain WRAS1 T was in the genus Thalassococcus and showed the highest 16S rRNA gene sequence similarity of 97.5 % to Thalassococcus halodurans JCM13833 T . Genome relatedness between strain WRAS1 T and T. halodurans JCM13833 T was computed using both average nucleotide identity and DNA-DNA hybridization with values of 74.11 % and 22.70±2.3 %, respectively. The genomic DNA G+C content calculated from the genome sequence of strain WRAS1 T was 65.6 %. On the basis of polyphasic analyses, strain WRAS1 T is considered to represent a novel species in the genus Thalassococcus, for which the name Thalassococcusprofundi sp. nov. is proposed. The type strain is WRAS1 T (=CGMCC 1.16123 T =MCCC 1K03253 T =KCTC 52696 T ).

A Gram-stain-negative, rod-shaped, non-motile, strictly aerobic strain, designated as MTEO17 T , was isolated from a 1000 m deep seawater sample of the Mariana Trench. Growth was observed at 10-45 °C (optimum, 37 °C), in the presence of 0.0-12.0 % NaCl (w/v; optimum, 3.0 %) and at pH 6.0-10.0 (optimum, pH 7.0-8.0). Phylogenetic analysis, based on the 16S rRNA gene sequence, revealed that strain MTEO17 T belonged to the genus Alcanivorax and showed the highest sequence similarity of 97.9 % to Alcanivorax nanhaiticus MCCC 1A05629 T . The estimated average nucleotide identity and DNA-DNA hybridization values between strain MTEO17 T and A. nanhaiticus MCCC 1A05629 T were 78.98 and 23.80 %, respectively. The significant dominant fatty acids were C16 : 0, summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c) and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). The polar lipids comprised two phosphatidylethanolamines, one phosphatidylglycerol, one unidentified phospholipid and four unidentified polar lipids. The DNA G+C content of strain MTEO17 T was 57.5 %. On the basis of the polyphasic evidence, strain MTEO17 T is proposed to represent a novel species of the genus Alcanivorax, for which the name Alcanivorax profundi sp. nov. is proposed. The type strain is MTEO17 T (=KCTC 52694 T =MCCC 1K03252 T ).

A Gram-stain-negative, strictly aerobic, short-rod-shaped bacterium, motile by a single polar flagellum, designated OUC007 T , was isolated from seawater at a depth of 1000 m in the Mariana Trench. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain OUC007 T formed a lineage within the family Salinisphaeraceae that was distinct from the most closely related genera Oceanococcus and Salinisphaera, with 16S rRNA gene sequences similarities ranging from 89.3 to 90.8 %, respectively. Strain OUC007 T grew with 0-7 % (w/v) NaCl (optimum, 2-3 %), at 10-45 °C (37 °C) and at pH 7.0-9.0 (7.0-8.0). The major respiratory quinone was ubiquinone-8 (Q-8). The polar lipids of strain OUC007 T comprised one phosphatidylethanolamine and three unidentified polar lipids. The predominant fatty acid (more than 10 % of total fatty acids) was summed feature 8 (C18 : 1ω7c or/and C18 : 1ω6c). The DNA G+C content of strain OUC007 T was 63.1 mol%. On the basis of polyphasic taxonomic analysis, the strain OUC007 T is considered to represent a novel species in a new genus of the family Salinisphaeraceae, for which the name Abyssibacter profundi gen. nov., sp. nov. is proposed. The type strain is OUC007 T (=KCTC 52933 T =MCCC 1K03450 T ).

A Gram-stain-negative, facultative anaerobic, non-motile, short-clavate and non-flagellated marine bacterium strain, designated JC075 T , was isolated from the Yongle Blue Hole in the South China Sea. Based on the 16S rRNA gene sequence, strain JC075 T was found to be closely related to Marinifilum albidiflavum FB208 T (97.10 %), Marinifilum flexuosum DSM 21950 T (96.43 %) and Marinifilum fragile JCM 15579 T (95.58 %), with less than 90.24 % sequence similarity to other genera of the family Marinifilaceae. The growth temperature was in the range of 10-37 °C, and the optimum temperature was 16 °C. Optimal growth occurred at pH 7.0 and in the presence of 3 % (w/v) NaCl. The isoprenoid quinone of strain JC075 T was identified as menaquinone-7 and the predominant fatty acids (>10 %) were iso-C15 : 0 (47.9 %), summed feature 9 (C17 : 1 or/and iso-C17 : 1ω9c; 18.7 %) and iso-C17 : 0 3-OH (14.9 %). The major polar lipids were one phosphatidylethanolamine, one phospholipid, one aminophospholipid, one glycolipid, one aminolipid and two unidentified lipids. The DNA G+C content of strain JC075 T was 35.8 mol%. On the basis of polyphasic analysis, strain JC075 T was considered to represent a novel species of the genus Marinifilum, for which the name Marinifilumbreve sp. nov. is proposed. The type strain is JC075 T (=KCTC 15646 T =MCCC 1K03477 T =JCM 32401 T ).

Rare Actinobacteria, known as non-Streptomyces, hold great potential to produce new bioactive compounds for drug development. A strain designated DSW09 T , which belongs those rare Actinobacteria, was isolated from surface seawater of the East China Sea. The cells were aerobic, Gram-positive, non-motile, non-spore-forming and rod-shaped (0.4 µm wide and 1.5-4.0 µm long). The closest relative was Euzebya tangerina F10 T (96.46 % of 16S rRNA gene similarity). Cell growth occurred at 15-45 °C (optimum, 25-30 °C), at pH 6.0-9.0 (pH 6.0-7.0) and at NaCl concentrations of 0.5-5.0 % (w/v; 1.0-4.0 %). The major cellular fatty acids were summed feature 3 (comprising C16 : 1ω7c and/or C15 : 0iso 2OH), C17 : 1ω8c and C16 : 0. The predominant polar lipid was diphosphatidylglycerol. The predominant menaquinone was MK-9(H4). The cell-wall peptidoglycan was A1 γ-type, containing meso-DPA. The major cell-wall sugars were rhamnose and ribose. The genome size was 5 509 297 bp with a 71.29 mol% G+C content for strain DSW09 T , while 4 781 440 bp with a 68.87 mol% G+C content for E. tangerina F10 T . The average nucleotide identity and digital DNA-DNA hybridization values between strain DSW09 T and E. tangerina F10 T were 73.44 % and 16.43 %, respectively. Based on phylogenetic, phenotypic, chemotaxonomic evidence and genomic analyses, strain DSW09 T is a novel species of genus Euzebya, for which the name Euzebya rosea sp. nov. is proposed. The type strain is DSW09 T (=DMS 104446 T =MCCC 1K03290 T ).

A Gram-stain-positive, endospore-forming, rod-shaped, motile and strictly aerobic strain, designated T3-209 T , was isolated from sediment sampled at a water depth of 1206 m of the southern Okinawa Trough at station T1 (25.07° N, 122.58° E) near the Tangyin hydrothermal vent during an expedition on the R/V Kexue in May 2014. The strain was able to grow at a temperature range of 10-42 °C (optimum 28 °C). Growth was observed at NaCl concentrations (w/v) of 0-6 % (optimum 0 %). The pH range for growth was 7.0-9.0 (optimum 8.0). The 16S rRNA gene sequence analysis indicated that strain T3-209 T belonged to the genus Bacillus within the family Bacillaceae and was most closely related to Bacillus drentensis LMG 21831 T and Bacillus bataviensis LMG 21833 T , with the same sequence similarity (97.0 %), but shared relatively low levels of similarity (92.6-96.9 %) to the type strains of other Bacillus species. The peptidoglycan type of strain T3-209 T was meso-diaminopimelic acid. The predominant cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0 and alcohol-C16 : 1ω7c. The respiratory quinone was menaquinone-7. The polar lipids of strain T3-209 T comprised phosphatidylglycerol, two unidentified phospholipids and one unidentified aminolipid. The DNA G+C content was 41.8 mol%. Combining results of phylogenetic analysis, phenotypic characterization and chemotaxonomic studies, strain T3-209 T represents a novel species of the genus Bacillus, for which the name Bacillus alkalitolerans sp. nov. is proposed. The type strain is T3-209 T (=KCTC 33631 T =DSM 29135 T =MCCC 1K00503 T ).

A rod-shaped, Gram-staining-negative, strictly aerobic, non-motile bacterium with no flexirubin-type pigment, designated as W201E T , was isolated from an intertidal sandy beach in Antarctica. The organism formed faintly yellow, round colonies on marine agar 2216E. The strain required sea salts for growth and grew optimally in the presence of 2 % (w/v) NaCl at pH 7.0, 20 °C. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain W201E T belonged to the genus Flavobacterium and showed the highest sequence similarity to Flavobacterium algicola NBRC 102673 T (96.5 %). The major respiratory quinone was menaquinone 6, and the predominant fatty acids were iso-C15 : 1 G, iso-C15 : 0, iso-C15 : 0 3-OH and summed feature 3 (which comprises C16 : 1ω7c and/or C16 : 1ω6c). The polar lipids of strain W201E T comprised one phosphatidylethanolamine, two unidentified aminolipids and three unidentified polar lipids. The DNA G+C content of strain W201E T was 34.1 mol%. On the basis of the polyphasic analyses, this isolate was considered to represent a novel species in the genus Flavobacterium, for which the name Flavobacterium ovatum sp. nov. is proposed. The type strain is W201E T (=KCTC 52693 T =MCCC 1K03251 T =CGMCC 1.16053 T ).