Effects of salinity on soil bacterial diversity and assembly processes in coastal soils.

Abstract

Coastal saline soil is an important reserve resource of agricultural land. Soil microorganisms play a key role in soil nutrient cycling. However, it is still far from clear about the effects of salinity on soil microbial community. We examined the effects of salinity on soil bacterial abundance, diversity, and community assembly, by collecting soil samples in coastal areas with three salinity levels (non-, mild-, and severe-salinity). Our results showed that the activity of dehydrogenase and the abundance of bacteria significantly decreased in the severe-saline soils, while the diversity of bacteria remained unchanged, compared with non- and mild-saline soils. Bacterial communities were clustered by salinity. Null model was used to infer bacterial community assembly processes. Salinity was the main driving factor for bacterial community assembly. Deterministic process driven by salinity played a leading role in controlling bacterial community composition in coastal saline soil. These findings suggested that coastal saline soils contain abundant microbes within the salinity range, and have a biological basis for soil improvement. Due to the high deterministic process of microbial community assembly, it would be difficult for alien species to colonize coastal saline soils. Salt-tolerant and indigenous strains are recommended when using microbial technology to reclaim coastal saline soils.