Root enzyme activity, soil chemistry, and shrub stem length in a long-term fertilization gradient experiment near Toolik Lake, Alaska (July 2018-2020)

As warming increases permafrost thaw and stimulates microbial activity, the resulting increases in nutrient availability are anticipated to alleviate plant nutrient limitations. These shifts aboveground may coincide with changes in root function below-ground, especially that of mycorrhizal degradative enzymes. This project characterized the responses of two contrasting tundra shrub species to a long-term experimental fertilization gradient. All data was collected from the US Arctic Long Term Ecological Research Network (LTER) fertilization gradient experiment established in 2006 in moist acidic tussock tundra. We measured the activity of five enzymes (leucine aminopeptidase, N-acetyl glucosaminidase, acid phosphatase, phenol oxidase, and peroxidase) on ectomycorrhizal (EcM)-colonized Betula nana roots and ericaceous Rhododendron tomentosum roots. We also characterized soil chemistry and measured stem lengths of Betula nana and Rhododendron tomentosum in the same plots.