九寨沟大气氮、磷和硫沉降的通量及水环境意义

The Fluxes and Possible Aquatic Impacts of Atmospheric Nitrogen,Sulfur and Phosphorous Deposition in Jiuzhaigou

为了解九寨沟大气氮、磷和硫沉降的现状及对水体景观的潜在影响,于2010—2011年在长海监测了干湿沉降,于2011—2012年度在日则和沟口监测了全沉降。长海和沟口位于旅游线上,而日则为背景点。结果显示,长海SO2-4的年通量为8.67 kg S/hm2,总无机氮(TIN)的年通量为3.04 kg N/hm2,都主要来自人为源。在总氮(TN)、总溶解性氮(TDN)、总磷(TP)和总溶解性磷(TDP)的全沉降方面,沟口和日则具有类似的特征,反映这两点的TN、TDN、TP和TDP全沉降主要受区域环境的影响,受当地旅游活动的影响相对较小。结合相关文献,发现氮沉降可能已超过九寨沟水体养分氮沉降临界值,湿沉降的TIN含量都超过我国自然保护区地表水环境TN的标准;过量硫沉降偶尔导致酸雨,威胁景观钙华的健康。为制定九寨沟的相关保护措施,今后有必要深入量化氮和硫沉降的来源及对水环境的影响程度。

In order to understand sulfur（S）,nitrogen（N） and phosphorous（P）deposition andits possible aquatic impacts in Jiuzhaigou,Sichuan,China,we monitored：（1）wet and dry depositionat Long Lake（LL） from 2010 to2011 and（2） bulk depositionat Jiuzhaigou Bureau（JB） and Rize from 2011 to 2012.LL and JB are located in the tourism region and Rize is a background site.The results show that annul fluxes of SO2-4and total inorganic nitrogen（TIN） were 8.67 kg S ha- 1and 3.04 kg N ha- 1,respectively,with most from anthropogenic sources.Bulk deposition fluxes of total nitrogen（ TN）,total dissolved nitrogen（ TDN）,total phosphorous（ TP） and total dissolved phosphorus（ TDP） were similar between JB and Rize,implying thatbulk deposition of TN,TDN,TP and TDP at the two sites was mainly affected by regional emissions rather than local tourist activities.Supported by other studies,we find that：（1） TN flux may have exceeded N critical load for local aquatic ecosystemsand（2） acid rain mainly caused by high sulfur deposition may place tufa scenery at degradation risk.To develop effective measures to protect Jiuzhaigou,we call for further studies to better quantify the sources and aquatic impacts of sulfur and nitrogen deposition in Jiuzhaigou.