Ammonia-oxidizer abundance, soil chemistry, stream chemistry, and meteorological data from two Adirondack headwater catchments, 2018-2020

The microbial oxidation of ammonia often regulates the cycling of nitrogen (N) in forest soils, with implications for primary productivity, water quality, and greenhouse gas fluxes. In this study, we compared abundances of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and complete ammonia-oxidizing Nitrospira clade B (ComaB) between two adjacent, upland forested catchments of headwater streams in the Adirondacks (USA) that have been intensively studied for their contrasting biogeochemistry, including large disparities in soil pH and stream nitrate concentrations. In addition to quantifying microbial functional types using qPCR, we measured soil macro- (P, NH4) and micro-nutrients (Fe, Cu) that were thought to delineate ecological niches of ammonia oxidizers. ComaB were highly abundant in both catchments, reaching up to 9.7 x 10^8 and 1.6 x 10^9 amoA copies/g soil in organic and mineral horizons, and ComaB exceeded AOA and AOB in 71% and 99% of soil samples, respectively. AOB, which are known for higher rates of ammonia oxidation, were significantly more abundant in both organic and mineral soil horizons of the high-N export catchment, relative to the low-N export soils. This data package includes ammonia-oxidizer abundance data (qPCR), soil chemistry, stream water chemistry, stream discharge, and meteorological data from the Archer Creek watershed at the Huntington Wildlife Forest, Newcomb, NY, collected from 2018 to 2020.