Soil protist functional composition shifts with atmospheric nitrogen deposition in subtropical forests ...

1. Soil protist plays a key role in ecological functions through predation and parasitism. However, little is known about how nitrogen (N) deposition and seasonal variations influence soil protist function in forest soils. 2. Here, we assessed firstly the impacts of N deposition (control, 50 kg N ha-1 yr-1, 100 kg N ha-1 yr-1, and 150 kg N ha-1 yr-1) on the functional composition of the soil protist community in summer and winter, using amplicon sequencing of environmental DNA from a subtropical natural forest. 3. We found that soil protists were dominated by consumers (42.6–51.6%), followed by parasites (32.9–40.9%) and phototrophs (3.2–13.1%), implying a predominant role of consumers and potential top-down effects on the other trophic groups in subtropical forest soils. The functional composition of soil protists was greatly influenced by N deposition, but these responses were dependent on seasonal variations. The diversity of phototrophs was lower in summer than in winter. Instead, an opposite pattern was ...