Distinct accumulation of bacterial and fungal residues along a salinity gradient in coastal salt-affected soils

Abstract Microbial residues may make a more significant contribution to soil organic carbon (SOC) than traditionally believed. However, little is known about the accumulation characteristics of fungal and bacterial residues and their contribution to SOC in salt-affected soils. We investigated changes in fungal and bacterial residues using amino sugar biomarkers along a salinity gradient in coastal salt-affected soils. As salinity increased, the content of fungal residue decreased from 337.6 to 111.6 mg kg−1, while the bacterial counterpart increased from 62.5 to 142.4 mg kg−1. The contribution of microbial residues to SOC was salinity-dependent. There was an increase for microbial residue contribution to SOC and a shift from fungal to bacterial residue dominated contribution to SOC with increasing salinity. Hence, salinization had a significant impact on microbial-mediated SOC accumulation.