天山中部巴音布鲁克高寒草原大气无机氮沉降

Inorganic N deposition in the Bayinbuluk alpine grassland of the central Tianshan mountains

随着我国经济的不断发展,人为活动导致的大气氮沉降显著升高,并已影响到偏远地区的生态系统.为了系统评价天山中部巴音布鲁克高寒草原的大气氮沉降现状,2010年5月至2011年12月对研究区域的氮素干、湿沉降进行观测分析.结果表明:研究区气态HNO3、NH3和NO2的年沉降通量分别为1.47、0.68和0.13 kg N·hm-2,颗粒物中铵态氮(NH4+)和硝态氮(NO3-)的年通量分别为0.23、0.25 kg N·hm-2;降水中NH4+-N和NO3--N的年沉降通量分别为2.47和1.59 kg N·hm-2.巴音布鲁克高寒草原的大气氮沉降通量为6.82kg N·hm-2.其中,湿沉降为4.06 kg N·hm-2·a-1,干沉降为2.76 kg N·hm-2·a-1.研究区氮沉降具有明显的季节变化特征:干沉降主要集中在春、夏季,占干沉降总量的72.1%;湿沉降主要集中在夏、秋季,占湿沉降总量的78.3%.

N deposition has increased significantly with economic development and intensive human activities in China and has affected natural ecosystems in remote areas. To evaluate the atmospheric N deposition of the Bayinbuluk alpine grassland of the central Tianshan Mountains, the dry and wet N depositions were monitored from May 2010 to December 2011. Fluxes of HNO3, NH3, NO2, par- tieulate ammonium and nitrate （pNH4＋and pNO3-） averaged at 1.47, 0.68, 0.13, 0.23 and 0.25 kg N· hm^-2 · a^-1, respectively. Wet depositions of NH4＋-N and NO3--N were 2.47 and 1.59 kg N · hm^-2 · a^-1 , respectively. Total atmospheric inorganic N deposition fluxes averaged at 6.82 kg N· hm^-2 · a^-1, and the wet and dry depositions were 4.06 and 2.76 kg N · hm^-2 ·a^-1 , respec- tively. Nitrogen deposition fluxes showed a significant seasonal change, with 72.1% of dry N depo- sition occurring in spring and summer, and 78.3% of wet N deposition concentrating in summer and autumn.