Echinicola arenosa sp. nov., isolated from marine sand.

A novel bacterium, designated CAU 1574T, was isolated from marine sand. Cells were Gram stain negative, aerobic, gliding and rod shaped. Growth was observed at 20-37 °C (optimum, 30 °C), a pH of 5.5-10.0 (optimum, 8.0), and 0-3.0% (w/v) NaCl concentrations (optimum, 1%). Based on the results of 16S rRNA gene sequence analyses, strain CAU 1574T belonged to the genus Echinicola, and showed the highest similarity to Echinicola shivajiensis JCM 17847T (97.5%). Phylogenomic analysis based on consisting of 92 core genes extracted from the genome sequences showed that strain CAU 1574T was affiliated with species in the genus Echinicola. The average nucleotide identity (ANI), average amino acid identity (AAI), and digital DNA-DNA hybridization (dDDH) values between strain CAU 1574T and the closely related species were below the cut-off values of 95-96, 90, and 70%, respectively used for species demarcation. The chemotaxonomic data of CAU 1574T were as follows: major isoprenoid quinone, MK-7; predominant polar lipids, phosphatidylethanolamine, two unidentified aminophospholipids and two unidentified lipids; major fatty acids, iso-C15:0, summed feature 3 (C16:1 ω6c/C16:1 ω7c). The 5.4 Mb genome included 20 contigs and 4237 protein-coding genes with a 39.8 mol% G + C content. Based on the phylogenetic, phenotypic, and physiological result, strain CAU 1574T represents a novel species of this genus Echinicola, for which the name Echinicola arenosa sp. nov. is proposed. The type strain is CAU 1574T (= KCTC 82410T = MCCC 1K05669T).

Pseudomarimonas arenosa gen. nov., sp. nov. isolated from marine sand.

A novel Gram-negative, aerobic, non-motile, rod-shaped, bacterial strain (CAU 1598T) was isolated from marine sand. Strain CAU 1598T grew well at 30 °C, pH 6.5-7.0 and with 3 % NaCl (w/v). Phylogeny results based on 16S rRNA gene sequencing indicated that the identified strain had the highest similarity (94.3%) to Pseudoxanthomonas putridarboris, indicating that strain CAU 1598T belongs to the family Xanthomonadaceae. Further, the fatty acid profile of the strain was primarily composed of C16:0, iso-C15 : 0, iso-C16 : 0, summed feature 3 (consisting of C16 : 1 ω7c/iso-C15 : 0 2-OH) and summed feature 9 (consisting of iso-C17 : 1 ω9c and/or C16 : 0 10-methyl), with ubiquinone-8 as the major isoprenoid quinone. The polar lipid profile included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphoglycolipid, an unidentified aminolipid and an unidentified lipid. The G+C content of the bacterial genome was 62.6 mol% and its 5.4 Mb length encompassed 144 contigs and 4236 protein-coding genes. These phenotypic, chemotaxonomic and phylogenetic data indicate that CAU 1598T belongs to a new genus and species, for which the name Pseudomarimonas arenosa gen. nov., sp. nov. is proposed. The type strain is CAU 1598T (=KCTC 82406T=MCCC 1K05673T).

Lewinella litorea sp. nov., isolated from marine sand.

A Gram-stain-negative, aerobic, non-motile and ovoid- or rod-shaped bacterial strain, designated HSMS-39T, was isolated from marine sand sampled at Hongsung, Republic of Korea. Strain HSMS-39T grew optimally at 30 °C and in the presence of 1.0-2.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain HSMS-39T fell within the clade comprising the type strains of Lewinella species, clustering with the type strain of Lewinella marina showing 16S rRNA gene sequence similarity of 99.1 %. It exhibited 16S rRNA gene sequence similarities of less than 95.5 % to the type strains of the other Lewinella species. Strain HSMS-39T contained MK-7 as the predominant menaquinone and iso-C17 : 1ω9c, iso-C15 : 0 and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) as the major fatty acids. The major polar lipids of strain HSMS-39T were phosphatidylethanolamine and one unidentified phospholipid. The DNA G+C content of strain HSMS-39T was 60.0 mol%. The mean DNA-DNA relatedness value between strain HSMS-39T and the type strain of L. marina was 15 %. The average nucleotide identity value between strain HSMS-39Tand the type strain of L. marina was 81.87 %. The phylogenetic and genetic data and differential phenotypic properties indicated that strain HSMS-39T is separated from other recognized species of the genus Lewinella. On the basis of the polyphasic data, strain HSMS-39T is considered to represent a novel species of the genus Lewinella, for which the name Lewinella litorea sp. nov. is proposed. The type strain is HSMS-39T (=KACC 19866T=NBRC 113585T).

Gramella sabulilitoris sp. nov., isolated from a marine sand.

A Gram-stain-negative, aerobic, non-spore-forming, motile by gliding and rod-shaped bacterial strain, designated HSMS-1T, was isolated from a marine sand collected from the Yellow Sea, Republic of Korea, and identified by a polyphasic taxonomic approach. The neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that HSMS-1T fell within the clade comprising the type strains of species of the genus Gramella. HSMS-1T exhibited 16S rRNA gene sequence similarity values of 99.0 and 98.7 % to the type strains of Gramella echinicola and Gramella sediminilitoris and of 93.3-98.5 % to the type strains of the other species of the genus Gramella. The ANI and dDDH values between HSMS-1T and the type strains of G. echinicola, Gramella gaetbulicola, Gramella forsetii, Gramella salexigens, Gramella portivictoriae and Gramella flava were 72.6-79.3 % and 17.4-22.2 %, respectively. Mean DNA-DNA relatedness value between HSMS-1T and the type strain of G. sediminilitoris was 18 %. HSMS-1T contained MK-6 as the predominant menaquinone and iso-C15 : 0, anteiso-C15 : 0, iso-C17 : 0 3-OH and iso-C16 : 0 as the major fatty acids. The major polar lipid of HSMS-1T was phosphatidylethanolamine. The DNA G+C content of HSMS-1T from genomic sequence data was 39.2 %. Distinguishing phenotypic properties, along with the phylogenetic and genetic distinctiveness, revealed that HSMS-1T is separated from recognized species of the genus Gramella. On the basis of the data presented, strain HSMS-1T is considered to represent a novel species of the genus Gramella, for which the name Gramella sabulilitoris sp. nov. is proposed. The type strain is HSMS-1T(=KACC 19899T=NBRC 113648T).

Sulfitobacter sabulilitoris sp. nov., isolated from marine sand.

A Gram-stain-negative, aerobic, non-motile and ovoid or rod-shaped bacterial strain, HSMS-29T, was isolated from a marine sand sample collected from the Yellow Sea, Republic of Korea. The neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strain HSMS-29T fell within the clade comprising the type strains of Sulfitobacter species. Strain HSMS-29T exhibited 16S rRNA gene sequence similarities of 97.2-98.4 % to the type strains of Sulfitobacter mediterraneus, Sulfitobacter porphyrae, Sulfitobacter marinus, Sulfitobacter pontiacus, Sulfitobacter litoralis, Sulfitobacter brevis, Sulfitobacter noctilucicola and Sulfitobacter dubius and 96.3-96.9 % to the type strains of the other Sulfitobacter species. The genomic ANI values of strain HSMS-29T with the type strains of S. mediterraneus, S. marinus, S. pontiacus, S. litoralis, S. brevis, S. noctilucicola and S. dubius were 72.66-74.99 %. The DNA-DNA relatedness value between strain HSMS-29T and the type strain of S. porphyrae was 17 %. Strain HSMS-29T contained Q-10 as the predominant ubiquinone and C18 : 1 ω7c as the major fatty acid. The major polar lipids of strain HSMS-29T were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminolipid and one unidentified lipid. The DNA G+C content of strain HSMS-29T was 65.0 mol% (HPLC) or 64.4 % (genome analysis). Distinguished phenotypic properties, along with the phylogenetic and genetic distinctiveness, revealed that strain HSMS-29T is separated from recognized Sulfitobacter species. On the basis of the data presented here, strain HSMS-29T is considered to represent a novel species of the genus Sulfitobacter, for which the name Sulfitobactersabulilitoris sp. nov. is proposed. The type strain is HSMS-29T (=KACC 19870T=NBRC 113549T).

Dredging Intensity: A Spatio-Temporal Indicator for Managing Marine Resources.

The sustainability of offshore sand reserves and the impact of their exploitation for coastal resilience can be assessed by resource managers via GIS. The GIS model to do this requires monitoring of the dredger location (including speed and displacement, if available). The designated borrow area is divided into grid cells, in this example, 100 × 100 m. The aggregate count of positions in each cell can be displayed in a graphic image called a "heat map" (or "density map" or "timeprint") where various intensities of colors represents the number vessel locations in each designated cell over the entire time period of interest as a surrogate for dredging intensity. Because sand dredging using a trialing hopper dredge is done at slow speeds, the aggregate time that a dredger spends in each cell can be modified by dredger speed to discriminate time spent actually removing sand from time spent in transit. If vessel displacements is also monitored, increases in displacement will also identify times and locations of active extraction. In this way, areas of disturbed benthic habitat can be identified, even if changes in bathymetry are not resolved.

Insights into the composition and assembly mechanism of microbial communities on intertidal microsand grains.

Introduction: Marine microorganisms are essential in marine ecosystems and have always been of interest. Currently, most marine microbial communities are studied at the bulk scale (millimeters to centimeters), and the composition, function and underlying assembly mechanism of microbial communities at the microscale (sub-100 micrometers) are unclear. Methods: The microbial communities on microsand grains (40-100 µm, n = 150) from marine sediment were investigated and compared with those on macrosand grains (400-1000 µm, n = 60) and bulk sediments (n = 5) using amplicon sequencing technology. Results: The results revealed a significant difference between microsand grains and macrosand grains. Microsand grains had lower numbers of operational taxonomic units (OTUs(97%)) and predicted functional genes than macrosand grains and bulk-scale samples. Microsand grains also showed greater intersample differences in the community composition and predicted functional genes than macrosand grains, suggesting a high level of heterogeneity of microbial communities at the microscale. Analyses based on ecological models indicated that stochastic processes dominated the assembly of microbial communities on sand grains. Consistently, cooccurrence network analyses showed that most microbial cooccurrence associations on sand grains were highly unstable. Metagenomic sequencing and further genome-scale metabolic modeling revealed that only a small number (1.3%) of microbe pairs showed high cooperative potential. Discussion: This study explored the microbial community of marine sediments at the sub-100 µm scale, broadening the knowledge of the structure and assembly mechanism of marine microbial communities.

Effects of Marine Sand on the Microbial Degradation of Biodegradable Plastics in Seawater and Biofilm Communities that Formed on Plastic Surfaces.

Four types of biodegradable plastics were evaluated for their biodegradability in seawater collected at Ajigaura coast, Japan, in the presence or absence of marine sand. One of the plastics, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), showed a degree of biodegradation in a seawater sample, and the addition of marine sand markedly accelerated its biodegradation. The addition of marine sand did not affect the bacterial composition of the biofilm that formed on PHBH, and the family Rhodobacteraceae, which was predicted to contribute to the degradation of PHBH, was dominant in biofilm communities regardless of the addition of marine sand. Marine sand may serve as a bacterial source, resulting in the accelerated degradation of PHBH.