Storage at room temperature is a cost-effective and practical preservation method for dry biocrust microbial communities

Microbial communities within biocrusts fulfill important ecological functions, particularly in dryland environments. Identifying the optimal conditions for transporting and storing biocrusts is essential to preserve and accurately analyze their microbial communities. However, the effectiveness of these preservation methods remains poorly understood. In this study, we collected dry biocrusts at different developmental stages (shifting sand, cyanobacteria-dominated, and moss-dominated) from the Qbuqi Desert in northern China. We examined the effects of different storage conditions, i.e. at room temperature (25 ± 2 °C) and low temperature (4 °C and −80 °C) over one month on the microbial community characteristics, including species composition, abundance and diversity. Our findings demonstrated that microbial community differences among the biocrust developmental stages were maintained even after one month of storage at room temperature. Compared to the control (analyzed immediately after sampling), storing biocrusts at 25 °C and 4 °C did not significantly alter biocrust assemblages, whereas storage at −80 °C increased the estimated gene copy number of Proteobacteria in cyanobacteria-dominated biocrusts. Furthermore, our results suggest that biocrust developmental stage and microbial community composition had minimal impact on the effectiveness of different storage methods, though caution should be kept for the prokaryotic communities. Overall, we recommend storing dry-collected biocrusts at room temperature as an effective and economic method for preserving microbial communities, particularly for DNA-based microbial studies from dryland soils with frequent monitoring of biocrust development at remote areas.