Abstract
Seasonal precipitation changes are increasingly severe in subtropical areas. However, the responses of soil nitrogen (N) cycle and its associated functional microorganisms to such precipitation changes remain unclear. In this study, two projected precipitation patterns were manipulated: intensifying the dry-season drought (DD) and extending the dry-season duration (ED) but increasing the wet-season storms following the DD and ED treatment period. The effects of these two contrasting precipitation patterns on soil net N transformation rates and functional gene abundances were quantitatively assessed through a resistance index. Results showed that the resistance index of functional microbial abundance (-0.03 ± 0.08) was much lower than that of the net N transformation rate (0.55 ± 0.02) throughout the experiment, indicating that microbial abundance was more responsive to precipitation changes compared with the N transformation rate. Spring drought under the ED treatment significantly increased the abundances of both nitrifying (amoA) and denitrifying genes (nirK, nirS, and nosZ), while changes in these gene abundances overlapped largely with control treatment during droughts in the dry season. Interestingly, the resistance index of the ammonia-oxidizing archaea (AOA) amoA abundance was significantly higher than that of the denitrifying gene abundances, suggesting that AOA were more resistant to the precipitation changes. This was attributed to the stronger environmental adaptability and higher resource utilization efficiency of the AOA community, as indicated by the lack of correlations between AOA gene abundance and environmental factors [i.e., soil water content, ammonium (NH4+) and dissolved organic carbon concentrations] during the experiment.
Highlights
Changes in seasonal precipitation distribution are increasingly severe in tropical and subtropical areas, with intensified droughts in winter and spring while more storms in summer (Cleveland et al, 2010; Wu et al, 2010; Sui et al, 2012; Zhang et al, 2012)
This study demonstrated that the responses of functional gene abundance were more sensitive to precipitation changes than the soil net N transformation rates, which further confirms the important roles played by soil microorganisms when assessing the responses of ecosystems to climate change
We found that the ammonia-oxidizing archaea (AOA) community had a greater ability to resist precipitation changes than denitrifiers, and that the amoA gene was less abundant than the denitrifying genes (Figure 2)
Summary
Changes in seasonal precipitation distribution are increasingly severe in tropical and subtropical areas, with intensified droughts in winter and spring while more storms in summer (Cleveland et al, 2010; Wu et al, 2010; Sui et al, 2012; Zhang et al, 2012). A better understanding of the effects of predicted seasonal precipitation changes on soil N transformations is necessary to evaluate the responses of regional ecosystem functions. Further studies about the responses of soil N transformation processes and functional microbes to seasonal precipitation changes in tropical and subtropical areas are urgently needed (Beier et al, 2012; Liu et al, 2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
