Data on investigation of N2O emission Regulated by Microorganisms in Mangrove Wetlands of Hainan, China

This study established an experiment simulating exogenous nitrogen input in mangrove wetlands from August 1, 2023 to January 27, 2024. According to the survey data on water quality in the study area, nitrogen in this area is mainly in the form of NO3--N, with an average concentration of 2mg/L. In this study, four nitrogen input concentrations were set: CK (0mg/L), N1 (2mg/L), N2 (4mg/L), and N3 (6mg/L), and 3 replicate samples were set for each treatment. The experiment lasted for a total of 180 days. Experimental soil was collected from the Dongzhai Port mangrove wetland, mixed uniformly, and then placed into experimental devices (PVC cylinders with a height of 80 cm and a diameter of 40 cm). The formal experiment started after a 2-week pre-cultivation period. Baseline soil physicochemical properties and microbial communities were tested before the experiment. After the experiment was initiated, soil samples and N₂O concentrations were collected every 15 days for testing, meanwhile, the temperature of the N2O detection chamber was recorded to calculate the N₂O flux data. At the end of the experiment (on day 180th), microbial samples were collected again to obtain 16S RNA data and functional gene data through detection. By these data, we monitored changes in soil physicochemical properties, N2O flux, and microbial community structure under the condition of exogenous nitrogen input, thereby investigating the N2O emission patterns, factors affecting N2O emissions, and microbial mechanisms driving N2O emissions under exogenous nitrogen input.
The results showed that nitrogen input increased the abundance and diversity of nitrifying bacteria, promoted nitrification. Cenarchaeum is the main factor affected the composition of nitrifying bacterial communities, while Unspecified_Proteobacteria (nirK), Unspecified_Gammaproteobacteria, and Unspecified_Bradyrhizobiaceae (nirS) are the key factors influenced the composition of denitrifying bacterial communities. The threshold effect of nitrogen input on N₂O flux and denitrifying bacteria is 2 mg/L. amoA and nosZ are key factors affected changes in N2O flux. A decrease in the abundance of functional genes involved in denitrification leads to a reduction in N2O emissions, and changes in mineral nitrogen content caused by nitrogen input further affect soil N2O emissions.