Is soil microbial diversity affected by soil and groundwater salinity? Evidences from a coastal system in central Italy

Little is known about composition, diversity and abundance of microbial communities in environments affected by primary soil salinization, such as coastal lagoon systems. The main objective of this study was to investigate the impact of lagoon salinity, soil type and land-use on inland soil and groundwater quality, and soil microbial community structure, diversity and gene abundance, as evaluated by T-RFLP (terminal-restriction fragment length polymorphism) and qPCR (quantitative polymerase-chain-reaction). For this purpose, 4 sites oriented along a groundwater salinity gradient (Fogliano lagoon, central Italy) were studied under different recreational, grazing and land-use conditions. Spatial variability in groundwater attributes was observed depending on salinity and soil electrical conductivity, both influenced by salt intrusion. Soil microbial community structure and diversity were affected by soil type and groundwater salinity. Our study provides a comprehensive overview of the spatial relationship between soil microbial community and soil degradation processes along a relatively underexplored environmental gradient.