Dissolved Organic Carbon, an Indicator of Soil Bacterial Succession in Restored Wetland under Freeze-Thaw Cycle

The moisture availability is of great significance to the physical, chemical and biological processes of soil, however, information regarding how freeze-thaw cycles (FTCs) affect the bacterial community of soil with different moisture contents is limited. In this work, we studied the relationship between FTCs and soil bacterial community under different moisture content (field capacity, FC and saturated moisture content, SMC). The results showed that FTCs decreased the richness and diversity of the soil bacterial community. Bacteria diversity were significantly decreased after the second FTC (FTC2). Thereafter, bacterial diversity with a saturated moisture content returned to the pre-freeze-thaw level, but the recovery of bacterial diversity in soil with the field capacity was lower than that of the saturated moisture content. Frequent FTCs accelerate the turnover of dissolved organic carbon DOC by affecting the carbon metabolism of microbial communities. Adjusting moisture to SMC can increase the stability of carbon. Our results provided reference to for the management of restored wetland.