Solving the global nitrogen problem: it's a gas!

Anthropogenic acceleration of global nitrogen cycling has doubled “reactive” nitrogen levels, degrading air and water quality and affecting human health. Denitrification is the primary process by which reactive nitrogen is recycled to inert N2. Unfortunately, past attempts to estimate denitrification at scales relevant to pollution and health problems have been associated with uncertainties, arising mainly from large variability in rates, difficulty measuring N2 fluxes over background levels, and the involvement of multiple reactants and products in other nitrogen-cycling processes. New approaches to quantifying broad-scale denitrification address some of these issues. Novel techniques allow detection of small changes in levels of N2 arising from denitrification. Recent models creatively identify “hot spots” of denitrification in the landscape. New remote-sensing products improve inputs to denitrification models. These developments, and others, hold promise for advancing our understanding of denitrification and its potential to mitigate the environmental impacts of reactive nitrogen.