Drivers shaping the diversity and biogeography of total and active bacterial communities in the South China Sea.
Bottom Line: Although the composition of both the total and active bacterial community was strongly correlated with environmental factors and weakly correlated with geographic distance, the active bacterial community displayed higher environmental sensitivity than the total community and particularly a greater distance effect largely caused by the active assemblage from deep waters.This might be due to a high competition between active bacterial taxa as indicated by our community network models.Based on these analyses, we speculate that high competition could cause some dispersal limitation of the active bacterial community resulting in a distinct distance-decay relationship.
Affiliation: State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiang'an, Xiamen, 361101, China; Institute of Marine Microbes and Ecospheres, Xiamen University, Xiang'an, Xiamen, 361101, China.Show MeSH
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Mentions: There was no relationship between the frequency of each OTU on the 16S rRNA and rDNA level (Fig.5). This suggests that the activity of an OTU (frequency on the 16S rRNA level) cannot be estimated based on its relative abundance in the community (frequency on the 16S rDNA). The most abundant taxa (>10%) in the DNA libraries were all below the 1:1 line in Fig.5a, including OTUs in the SAR11 clade, the Actinobacteria Marine group and the Rhodobacteriaceae, whereas the most abundant taxa (>15%) in the RNA libraries were all above the 1:1 line, including OTUs of the Cyanobacteria and Methylobacterium (Fig.5a). In addition, the moderately abundant taxa (5–10%) in the DNA libraries below the 1:1 line included members of the SAR11 and SAR324 clades, the Rhodobacteriaceae, Actinobacteria Marine group and Sporichthyaceae (Fig.5b). The taxa accounting for 5–15% in the RNA libraries above the 1:1 line included members of the Cyanobacteria, Methylobacterium, Erythrobacter, Sphingopyxis, Ralstonia, Pseudomonas, Candidatus Thiobios, Acidimicrobineae, Verrucomicrobia and one SAR11 taxon. In general, low-abundance taxa in the total community had higher 16S rRNA: rDNA ratios, and possibly higher activities, than relatively more abundant taxa.
Affiliation: State Key Laboratory of Marine Environmental Sciences, Xiamen University, Xiang'an, Xiamen, 361101, China; Institute of Marine Microbes and Ecospheres, Xiamen University, Xiang'an, Xiamen, 361101, China.