Atmospheric Nitrate Deposition and Enhanced Dissolved Organic Carbon Leaching

Atmospheric NO 3 − deposition has the potential to disrupt litter decomposition in temperate forests by suppressing enzymes responsible for lignin degradation. A reduction in phenol oxidase activity could potentially trigger an increase in soluble phenolic compounds, which in turn are known to decrease the activity of cellulolytic enzymes like β‐glucosidase. Our study investigated whether the inhibition of lignin degradation by experimental NO 3 − deposition could increase soluble phenolics in soil, suppress β‐glucosidase activity, and potentially explain a greater export of dissolved organic C (DOC) from northern hardwood ecosystems. We found no evidence that the suppression of phenol oxidase by NO 3 − additions increased soluble phenolics in mineral soil, nor did we find a strong inverse relationship between soluble phenolics and β‐glucosidase activity. It appears that reductions in mineral soil lignolytic activity induced by experimental deposition are not responsible for greater DOC export from soil.