Background
Bacterial community composition in the marine environment differs from one geographical location to another. Reports that delineate the bacterial diversity of different marine samples from geographically similar location are limited. The present study aims to understand whether the bacterial community compositions from different marine samples harbour similar bacterial diversity since these are geographically related to each other.Methods and Principal Findings
In the present study, 16S rRNA deep sequencing analysis targeting V3 region was performed using Illumina bar coded sequencing. A total of 22.44 million paired end reads were obtained from the metagenomic DNA of Marine sediment, Rhizosphere sediment, Seawater and the epibacterial DNA of Seaweed and Seagrass. Diversity index analysis revealed that Marine sediment has the highest bacterial diversity and the least bacterial diversity was observed in Rhizosphere sediment. Proteobacteria, Actinobacteria and Bacteroidetes were the dominant taxa present in all the marine samples. Nearly 62–71% of rare species were identified in all the samples and most of these rare species were unique to a particular sample. Further taxonomic assignment at the phylum and genus level revealed that the bacterial community compositions differ among the samples.Conclusion
This is the first report that supports the fact that, bacterial community composition is specific for specific samples irrespective of its similar geographical location. Existence of specific bacterial community for each sample may drive overall difference in bacterial structural composition of each sample. Further studies like whole metagenomic sequencing will throw more insights to the key stone players and its interconnecting metabolic pathways. In addition, this is one of the very few reports that depicts the unexplored bacterial diversity of marine samples (Marine sediment, Rhizosphere sediment, Seawater) and the host associated marine samples (Seaweed and Seagrass) at higher depths from uncharacterised coastal region of Palk Bay, India using next generation sequencing technology. 相似文献The luminescence properties of pure and ZrO2: Eu+3 nanophosphors with different concentration of the Eu+3 is synthesised and studied. A novel and environment benign microwave-induced hydrothermal process is used to synthesise the nanoparticles. As-formed pure ZrO2 nanoparticles were X-ray amorphous, and upon calcination at higher temperatures, they crystallise to a combination of both cubic and tetragonal phases. However, the ZrO2: Eu+3 nanophosphors prepared through the same technique under similar conditions yield exclusively cubic ZrO2, and it entirely depends on the concentration of Eu+3 as revealed by XRD studies. The nanoparticles are found to be spherical, non-porous and agglomerated as observed by SEM. The surface area of the nanoparticles of pure ZrO2 is found to be 30 m2/g for as-formed samples and 130 m2/g for calcined samples by BET studies. The increase in the surface area for calcined sample is due to the escaping of the adsorbed hydroxyl groups from the surface of the nanoparticles. The photoluminescence properties of the pure and Eu+3-doped ZrO2 nanoparticles were measured under 251 nm excitation wavelength. Under this excitation, pure ZrO2 gives the emissions at 394 nm, whereas Eu+3-doped nanoparticles gives the emissions at 613 nm, which corresponds to inter-f-f transition from 5D0 ➔7F2 (613 nm) and is arising due to electronic dipole in the Eu+3 activator ion. CIE colour space (x, y) coordinates corresponding to 613 nm in the CIE chromaticity diagram is 0.680, 0.319.
Graphical Abstract