title: High beta diversity of bacteria in the shallow terrestrial subsurface.
abstract: While there have been a vast number of studies on bacterial alpha diversity in the shallow terrestrial subsurface, beta diversity - how the bacterial community composition changes with spatial distance - has received surprisingly limited attention. Here, bacterial beta diversity and its controlling factors are investigated by denaturing gradient gel electrophoresis and cloning of samples from a 700-cm-long sediment core, the lower half of which consisted of marine-originated sediments. According to canonical correspondence analysis with variation partitioning, contemporary environmental variables explain beta diversity in a greater proportion than depth. However, we also found that community similarity decayed significantly with spatial distance and the slopes of the distance-decay relationships are relatively high. The high beta diversity indicates that the bacterial distribution patterns are not only controlled by contemporary environments, but also related to historical events, that is, dispersal or depositional history. This is highlighted by the different beta diversity patterns among studied sediment layers. We thus conclude that the high beta diversity in the shallow terrestrial subsurface is a trade-off between historical events and environmental heterogeneity. Furthermore, we suggest that the high beta diversity of bacteria is likely to be recapitulated in other terrestrial sites because of the great frequency of high geochemical and/or historical variations along depth.
authors.affiliation: State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, East Beijing Road 73, Nanjing 210008, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Wang
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Wu
authors.forename: Hongchen
authors.initials: H
authors.lastname: Jiang
authors.forename: Chunhai
authors.initials: C
authors.lastname: Li
authors.forename: Hailiang
authors.initials: H
authors.lastname: Dong
authors.forename: Qinglong
authors.initials: Q
authors.lastname: Wu
authors.forename: Janne
authors.initials: J
authors.lastname: Soininen
authors.forename: Ji
authors.initials: J
authors.lastname: Shen
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D044822:Biodiversity; D003001:Cloning, Molecular; D016172:DNA Fingerprinting / Q000379:methods; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D009691:Nucleic Acid Denaturation; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial