Background and aims

Mosses generate bryotic pulses through intracellular content leakage during desiccation and rehydration; however, their effects on soil carbon (C) and nitrogen (N) resources and microbial biomass remain unclear.

Methods

We measured C and N concentrations in bryotic pulses from two moss species (Actinothuidium hookeri and Hylocomium splendens) over 5 days after they were subjected to severe, moderate or no desiccation followed by rehydration. Mosses from three desiccation treatments were transplanted onto the soil surface and rehydrated to assess the effects of bryotic pulses on soil C and N and microbial biomass.

Results

The concentrations of C and N (total organic C, total N, total soluble sugars, total free amino acids, ammonium and nitrate) released by desiccated mosses peaked within 3 h and subsequently decreased following rehydration. Severely desiccated mosses released greater cumulative concentrations of C and N than moderately desiccated and non-desiccated mosses during rehydration. H. splendens exhibited higher cumulative C and N concentrations than A. hookeri after severe desiccation and rehydration. The positive effects of severely and moderately desiccated mosses on soil C and N resources (dissolved organic C, total dissolved N, soluble sugars and free amino acids) varied between moss species and decreased following rehydration. Desiccated and nondesiccated mosses generally decreased soil ammonium and nitrate concentrations during rehydration. Only severely desiccated H. splendens increased soil microbial biomass C and N after rehydration.

Conclusion

Our findings highlight the notable role of bryotic pulses from desiccated–rehydrated mosses in increasing soil C and N resources and microbial biomass.