Effects of freezing and thawing on microorganisms

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 bacteria in soil with different moisture content (field capacity, FC and saturated moisture content, SMC). The results showed that FTCs affected the richness and diversity of the soil bacterial community. Bacteria diversity were significantly affected after the second FTC. Thereafter, bacteria diversity with a saturated moisture content returned to the pre-freeze-thaw level, but the recovery of bacteria in soil with the field capacity was lower than that of the saturated moisture content. Frequent FTCs accelerate the turnover of 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.