『Abstract
　Nitrogen (N) fluxes of a slope mire in the German Harz Mountains were monitored to study the effect of increased N deposition on the N retention of the mire. In addition, the N content of mire pore water beneath different plant species was analyzed to assess N retention ability of plants. Atmospheric N deposition at the study site was 4.9±0.4 g N m^-2 year^-1 averaged for the study period of 2002 and 2003, with forest stand deposition being the largest share. Discharge was the main output pathway of N with a rate of 1.9±0.3 g N m^-2 year^-1. The mire showed a high N retention rate of 67％. Short-term N accumulation rate was 3.6 g N m^-2 year^-1. Differences in mire pore water N concentration under different vegetation cover indicate a lower N retention ability for ombrotrophic Sphagnum plants.

Keywords: Critical load; Nitrogen deposition; Nitrogen retention; Ombrotrophic peatland; Sphagnum』

1. Introduction
2. Materials and methods
　2.1. Study site
　2.2. Field sampling and analysis
　　2.2.1. N input, N output, and N retention
　　2.2.2. Mire pore water
　　2.2.3. Statistical analysis
3. Results and discussion
　3.1. N input and N output
　3.2. N concentrations of mire pore water
　3.3. N retention and N accumulation
4. Conclusions
Acknowledgements
References