title: Seawater inundation from the 2011 Tohoku tsunami continues to strongly affect soil bacterial communities 1 year later.
abstract: The effects of inundation caused by the 2011 Tohoku tsunami on soil bacterial communities in agricultural fields were evaluated. Bacterial communities were compared across three different types of soil, unflooded field (UF) soil, soil flooded for 2 weeks (short term (ST)), and soil flooded for 2 months (long term (LT)), using polymerase chain reaction-pyrosequencing of 16S rRNA genes. Acidobacteria were dominant in UF, with a relative abundance of approximately 35 %, and Proteobacteria dominated flooded soils (30-67 %). Hierarchical cluster analysis indicated that the community structure of soil bacteria in flooded soils (ST and LT) clearly differed from that in UF. Differences between LT and ST fields were rarely observed in terms of chemical properties and microbial community structure at the phylum level. However, sulfur-oxidizing bacteria (SOB) and nitrite-oxidizing bacteria (NOB) in LT tended to occur at high and low abundances, respectively. Halothiobacillus, a halotolerant SOB, was detected in all LT fields. Unexpectedly, a zeta-Proteobacteria, which had previously only been detected in marine environments, was detected in LT fields only. Our results demonstrate that the effects of the 2011 Tohoku tsunami on soil bacterial communities in agricultural fields may have lasted at least 1 year. Furthermore, SOB, NOB, and zeta-Proteobacteria may serve as indicators of the effects of seawater inundation on microorganisms.
authors.affiliation: Department of Biotechnology, Faculty of Bioresource Sciences, Akita Prefectural University, 241-438 Kaidobata-Nishi, Shimoshinjo-Nakano, Akita, 010-0195, Japan.
authors.forename: Ryoki
authors.initials: R
authors.lastname: Asano
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Nakai
authors.forename: Wataru
authors.initials: W
authors.lastname: Kawada
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Shimura
authors.forename: Tamio
authors.initials: T
authors.lastname: Inamoto
authors.forename: Jun
authors.initials: J
authors.lastname: Fukushima
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D017753:Ecosystem; D007564:Japan; D008969:Molecular Sequence Data; D010802:Phylogeny; D012623:Seawater / Q000032:analysis*; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D057192:Tsunamis
chemical_list: D012987:Soil