Phosphorus forms in the sediment of seagrass meadows affected mainly by fungi rather than bacteria: a preliminary study based on 31P-NMR and high-throughput sequencing

Microorganisms play an important role in the circulation of phosphorus (P) in the sediment of coastal wetland ecosystems. In this study, solution ³¹P nuclear magnetic resonance (NMR) was used to determine different forms of P in the sediments of four different seagrass meadows and a bare tidal flat, while high-throughput 16S and ITS rRNA gene sequencing was used to determine the microbial community composition. The solution ³¹P-NMR spectra revealed six forms of the P compounds detected by the NaOH-EDTA extraction of sediments, where Ortho-P was the most dominant P compound, followed by Mono-P. The Po compounds were more varied in the seagrass meadow sediments and more abundant compared to the bare tidal flat. Bacterial communities in the sediments collected from E. acoroides and fungal communities in the bare tidal flat were relatively different from those at the other sites. The relative abundance of P-cycling-related fungi belonging to the phylum Ascomycota was 26.20% and was much higher than that of bacteria (only 0.29%) belonging to the class Bacilli. Mono-P was the major factor determining the distribution of P-cycling-related fungi and negatively correlated with the relative abundance of Aspergillus and Trichoderma. We believe that fungi can affect P forms in the sediment of seagrass meadows more than bacteria.