Linking changes in snow cover with microbial nitrogen cycling functional gene abundance and expression in agricultural soil.

In eastern Canada, climate change-related warming and increased precipitation may alter winter snow cover, with potential consequences for soil conditions, nitrogen (N) cycling, and microbes. We conducted a 2-year field study aimed at determining the influence of snow removal, snow accumulation, and ambient snow in a potato-barley crop system on the abundance and expression of denitrifier (nirS, nirK, nosZ) and nitrifier (ammonium oxidizing archaeal (AOA) and bacterial (AOB) amoA) genes. Denitrifier and nitrifier abundance and expression results were compared to N2O production, soil atmosphere accumulation, and surface fluxes.

Similar temperature responses suggest future climate warming will not alter partitioning between denitrification and anammox in temperate marine sediments.

Removal of biologically available nitrogen (N) by the microbially mediated processes denitrification and anaerobic ammonium oxidation (anammox) affects ecosystem N availability. Although few studies have examined temperature responses of denitrification and anammox, previous work suggests that denitrification could become more important than anammox in response to climate warming. To test this hypothesis, we determined whether temperature responses of denitrification and anammox differed in shelf and estuarine sediments from coastal Rhode Island over a seasonal cycle.