Print PageTerrestrial nitrogen cycling is largely driven by specific groups of bacteria and archaea, which are sensitive to environmental changes. While many studies have examined the effects of climate change on microbial (mostly bacterial and fungal) communities and on rates of nitrogen cycling separately, few studies have examined both responses simultaneously. Because nitrogen is an important plant nutrient in many ecosystems, changes in nitrogen cycling rates and nitrogen availability can influence plant productivity and atmospheric carbon concentrations. To better understand how climate change affects the nitrogen cycle and how changes in nitrogen cycling may feed back to climate change, we examined how warming and altered precipitation affected seasonal dynamics of ammonia-oxidizing bacterial and archaeal communities and nitrogen cycling rates in an old old-field ecosystem at the Boston Area Climate Experiment (BACE).
Results/Conclusions
Warming sometimes accelerated various nitrogen cycling processes (e.g., net nitrogen mineralization, nitrification, and potential nitrification), but this effect differed depending on the time of year and the precipitation treatment. We found nonlinear responses to both warming and precipitation treatments. In addition, we found that while the abundance of ammonia oxidizing archaea responded to warming treatments in some seasons, ammonia oxidizing bacteria did not respond to warming treatments at all. We also examined the seasonal community structure of ammonia oxidizing archaea and bacteria, which we place in the context of the treatment effects on nitrogen cycling rates. Our results may provide insight into some of the mechanisms by which rates of nitrogen cycling respond to warming and altered precipitation and how these responses feed back to climate change.
