Chemical Speciation Defines Ammonia-Oxidizer Distribution in Yellowstone Hot Springs

Samples were collected from Yellowstone National Park hot springs with the goal of spanning a large range of pH (1-9) and total dissolved ammonia concentrations (0.22 micromolal to 57.2 millimolal). DNA was extracted from these samples for 16S rRNA gene amplicon sequencing in order to identify the presence of hot spring ammonia-oxidizing archaea (AOA). The combination of collected geochemical data and 16S rRNA gene amplicon data has allowed for the identification of an environmental substrate threshold and an apparent maximum in ammonium concentrations for hot spring AOA.