Soil microbial communities play an essential role in terrestrial biogeochemical cycling, and it is vital to understand how shifts in microbial communities are linked to large-scale ecosystem effects. The terrestrial nitrogen cycle is an important ecosystem process that is largely driven by specific taxonomic 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, fewer studies have examined both responses. Here, we summarize the results of an experiment on the effects of warming and altered precipitation on ammonia-oxidizing bacterial and archaeal communities and nitrogen cycling rates in an old field at the Boston Area Climate Experiment (BACE). The goal of this experiment is to determine if altered precipitation and warming interact to affect nitrogen cycling rates and the community structure of ammonia oxidizers and whether this effect varies depending on the time of year.
Results/Conclusions
Warming increased various measures of nitrogen cycling rates (e.g., net nitrogen mineralization, nitrification, and potential nitrification), and in some cases, this effect differed depending on the time of year and the precipitation treatment. In addition, we examined the community structure of ammonia-oxidizing archaea and bacteria in light of the observed increases in nitrogen cycling rates. By synthesizing this information, we hope to better understand some of the mechanisms through which warming and altered precipitation affect rates of nitrogen cycling.
