A review on moss nitrogen and isotope signatures evidence for atmospheric nitrogen deposition.

Moss nitrogen (N) concentration and isotopic composition (δN) values can reveal a better understanding of atmospheric N deposition patterns. Here, we summarize the moss N content and δN signatures using data compiled from 104 papers. Based on the dataset, we summarize the models for assessing the level and reduced (NH): oxidised compounds (NO) ratio of atmospheric N deposition. Results showed a historical increase in N concentration and N depletion of specimen mosses close to anthropogenic N sources from intensive animal production and agricultural activities (NH emission) since the 1800s. However, an increase of moss N with a less negative N observed in the last three decades could be due to a substantial fossil fuel combustion contributed NO emission. Spatially, N deposition in Europe decreased due to successful control actions, but Asia has become a hotspot for NH emission from agriculture. The present results highlight the importance of moss N and δN values for estimating atmospheric N deposition patterns at spatio-temporal trends.