用苔藓氮含量和氮同位素值指示庐山大气氮沉降

Indication of Atmospheric Nitrogen Deposition in Mt. Lushan by Nitrogen Concentration and Nitrogen Isotope in Mosses

对庐山风景区不同海拔高度(263～1 400 m)上31个石生苔藓(Haplocladium microphyllum)氮含量〔w(TN),以干质量计〕和氮同位素值(δ15N)进行了分析.苔藓w(TN)与海拔高度(Laltitude)的关系〔w(TN)=3.11-7.85×10-4Laltitude〕表明,在庐山风景区,随着海拔高度的升高,苔藓w(TN)呈逐渐下降趋势.根据前人研究的苔藓w(TN)与大气氮沉降量的定量关系,估算出庐山山顶和山脚的大气氮沉降量分别为24.61和41.72 kg (hm2.a).苔藓δ15N在-4‰～-2‰范围出现的频率最高,表明庐山风景区大气氮沉降主要来源于农业或自然土壤中氮的释放.

The total nitrogen concentration（w（TN）,dry weight） and δ15N signature of 31 epilithic mosses Haplocladium microphyllum from different altitudes（263-1400 m） of Mt.Lushan were determined.The relationship（w（TN）=3.11-7.85×10-4Laltitude） between total nitrogen concentration and altitude（Laltitude） showed that total nitrogen concentration in mosses gradually decreased with the increase of altitude in Mt.Lushan.According to the quantitative relationship reported previously between the total nitrogen concentration in mosses and atmospheric nitrogen deposition,we estimated atmospheric nitrogen deposition to be 24.61 kg （hm2·a） at the summit and 41.72 kg （hm2·a） at the foot of Mt.Lushan.The δ15N values in the mosses weve mainly concentrated between-4‰ and-2‰,suggesting that atmospheric nitrogen deposition in Mt.Lushan mainly comes from the nitrogen release of agricultural and natural soil.