Emission of Nitrogen Gas, Nitrous Oxide, and Carbon Dioxide on Rehydration of Dry Feathermosses

Two experiments were conducted to examine the fate of N in feathermosses when mosses were dehydrated and then rewetted. In the first experiment, dry feathermoss shoots were sealed in containers where the N 2 was replaced by He. After rewetting and incubating for 20 h, gas in the containers had significant amounts of N 2 and N 2 O and had elevated levels of CO 2 compared with mosses maintained in a moist condition or dried mosses that had not been rewetted. In the second experiment, samples of feathermoss were subjected to five dry–wet cycles. By the fifth cycle, there was a 9% reduction in mass of the moss and a similar decline in quantity of N. The results of this study suggest that in forests undergoing dry–wet cycles, there is a potential for N volatilization directly from the moss layer. After drying and rewetting, the moss releases sugars and soluble forms of N into the substrate, creating a suitable environment for aerobic denitrification. Thus, more N is lost from an already N‐deficient ecosystem.