Universal temperature sensitivity of denitrification nitrogen losses in forest soils

Warming affects forest soil denitrification and nitrogen losses. The authors show that temperature enhances nitrous oxide and dinitrogen but varies by soil; temperature sensitivities are similar across soils but are higher for dinitrogen, suggesting complete denitrification in a warmer climate. Soil nitrous oxide (N2O) and dinitrogen (N-2) emissions from denitrification are crucial to the nitrogen (N) cycle. However, the temperature sensitivities (Q(10)) of gaseous N losses in forest soils are poorly understood, with implications for prediction of N cycle responses to warming. Here, we quantify temperature sensitivities of denitrification-derived potential N2O and N-2 production. Using soils from 18 forest sites in China along a 4,000 km north-south transect we find that N2O and N-2 production rates increased with temperature, with large variations across soils. In contrast, the Q(10) values for N2O (2.1 & PLUSMN; 0.5) and N-2 (2.6 & PLUSMN; 0.6) were similar across soils. N-2 was more sensitive to temperature than N2O, suggesting that warming could promote complete denitrification. Moreover, the Q(10) for denitrification (2.3 & PLUSMN; 0.5) was comparable to Q(10) for aquatic sediments. This finding of universal temperature sensitivity of gaseous N losses from denitrification will facilitate modelling N losses in response to warming globally.

Automated summary

Warming affects forest soil denitrification and nitrogen losses, with temperature enhancing nitrous oxide and dinitrogen but varying by soil. The temperature sensitivities are similar across soils but higher for dinitrogen, suggesting complete denitrification in a warmer climate. This finding of universal temperature sensitivity of gaseous N losses from denitrification will facilitate modeling N losses in response to warming globally.