Moisture determined spatial heterogeneity of river sediment/soil Anaerolineaceae communities in semiarid region

Abstract:

[Background] The members of Anaerolineaceae family (e.g., Anaerolinea genus) from Anaerolineales order of Anaerolineae class are mainly distributed in marine sediments and wetland soils. However, little is known about the spatial heterogeneity of sediments/soils Anaerolineaceae communities and environmental drivers under a specific moisture gradient. [Objective] To elucidate the spatial heterogeneity of Anaerolineaceae communities and core environmental drivers under the moisture gradient along aquatic, hygrophic and xerophytic environments in river system from semiarid region of Mongolian Plateau, and deciphering the early predicting function of Anaerolineaceae communities during the rewetting process of drought-induced shrinking river wetland. [Methods] High-throughput sequencing of 16S rRNA gene, Pearson correlation and variation partitioning analyses were employed to detect the compositions, abundance, spatial distribution of sediment/soil different populations in Anaerolineaceae communities and environmental drivers under the moisture gradient. [Results] The 15 populations of Anaerolineaceae communities were mainly distributed in the aquatic, hygrophic environments, which were positively driven by moisture, pH, sand and ammonia nitrogen, while negatively driven by salinity, total nitrogen and total phosphorus, silt and clay particles. Exceptionally, Uncultured_us15 population was negatively driven by sand and ammonia while positively driven by silt and salinity. Interestingly, 9 and 6 populations in Anaerolineaceae communities showed positive and negative correlation with total organic carbon, respectively. Variation partitioning analysis showed that moisture, ammonia, salinity, organic carbon and pH explained the spatial variation of Anaerolineaceae communities with 64.8%, 8.9%, 7.5%, 2.2% and 1.7%, respectively. [Conclusion] Anaerolineaceae communities demonstrated obvious spatial heterogeneity, which preferred to aquatic and hygrophic environments with high moisture, sand, ammonia and high pH rather than xerophytic environments with relatively rich salinity and nutrition from semiarid region of Mongolia Plateau. The spatial heterogeneity of Anaerolineaceae communities was mainly driven by moisture. Anaerolineaceae communities were key indicators predicting the rewetting process of drought-induced shrinking river wetland, which were probably autotrophic or heterotrophic ammonia-oxidizing bacteria.

Key words:Semiarid area, Moisture gradient, Anaerolineaceae communities, Spatial heterogeneity, Core drivers