Abstract. Increasing trends of atmospheric nitrogen (N) deposition resulting from a large number of anthropogenic emissions of reactive N are dramatically altering the global biogeochemical cycle of N. Nitrogen uptake by mosses occurs mainly from the atmosphere, making it a competent bio-indicator of N deposition. However, high uncertainties exist when using mosses to indicate N deposition, especially in choosing sampling periods and sampling frequencies. In this study, atmospheric N deposition and moss N content in the urban–agro–forest transition, a region with a high N deposition level of 27.46–43.70 kg N hm−2 yr−1, were monitored, and the method for monitoring atmospheric N deposition by mosses was optimized. We found that the optimal sampling frequency is within 6 months per time, and the optimal sampling times are winter (January and February), autumn (October and November), and summer (July and August), which provides us with a more accurate estimation of atmospheric N deposition than other scenarios. In addition, the moss N content serves as a more reliable N species. This study eventually allowed mosses to be used more effectively and sensibly as an indicator of atmospheric N deposition and helped to improve the accuracy of the model for quantifying N deposition.

中文翻译：

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城市-农林-森林转型过程中苔藓对大气氮沉降和氮饱和度的响应模式

摘要。大量人为排放活性氮导致大气氮沉降呈增加趋势，正在极大地改变氮的全球生物地球化学循环。苔藓吸收的氮主要来自大气，使其成为氮沉降的有效生物指标。然而，用苔藓来指示氮沉降存在很大的不确定性，特别是在采样周期和采样频率的选择上。本研究对城市-农田-森林过渡区的大气氮沉降和苔藓氮含量进行了监测，该地区氮沉降水平较高，为27.46~43.70 kg N hm−2 yr−1，并提出了大气氮沉降监测方法。优化了苔藓的氮沉积。我们发现最佳采样频率是每次6个月以内，最佳采样时间是冬季（1月和2月）、秋季（10月和11月）、夏季（7月和8月），这为我们提供了更准确的估计大气氮沉降量高于其他情景。此外，苔藓氮含量是更可靠的氮物种。这项研究最终使苔藓能够更有效、更合理地用作大气氮沉降的指标，并有助于提高量化氮沉降模型的准确性。