横断山区草本沼泽湿地水体氮含量空间分布特征

草本沼泽是横断山区重要的湿地类型，为探明横断山区草本沼泽湿地水体中总氮、硝氮和氨氮的空间分布特征及其控制因素，于2014—2017年在横断山区对典型草本沼泽湿地开展水样采集和分析工作，同时收集降水量、地表大气温度、水温、水深、人口数量、GDP、家畜数量等环境数据。结果表明：1）横断山区草本沼泽湿地水体中总氮含量表现出明显的纬向地带性和垂直地带性：总氮含量随纬度和海拔增加而下降，水温是控制这种地带性特征的主要因素。同时，随经度增加，水体中总氮含量也显著增加，社会经济发展因素是导致这种分布特征的主要原因；2）横断山区沼泽湿地水体中硝氮和氨氮含量在海拔梯度上的变化趋势不明显；3）随经度和纬度增加，沼泽湿地水体中硝氮含量逐渐增加，导致这种现象的主要原因是水深和水温；4）随经度增加，沼泽湿地水体中氨氮的含量逐渐增加，但氨氮含量与自然环境因素和社会经济发展因素均无显著相关性。

Distribution of nitrogen in the water of marshes across the Hengduan Mountain area

Marsh is an important wetland type in Hengduan Mountain area (HMA). To explore the distribution and control factors of total nitrogen (TN), nitrate nitrogen (NN), and ammonias nitrogen (AN) in water of marshes across HMA, water samples were taken and analyzed during 2014-2017. Meanwhile, environmental data, including precipitation, air temperature, water temperature, water depth, population, gross domestic product (GDP), and number of livestock were collected as well. The results showed that: 1) the content of TN in water of marshes followed the law of latitudinal zonality and vertical zonality, i.e., the content of TN decreased with the increase of latitude and altitude across the HMA. Water temperature was a control factor of the distribution of TN along the latitude and altitude. Meanwhile, the content of TN increased with the increase of longitude, which may drive by socio-economic factors. 2) The contents of NN and AN in water of marshes did not change significantly along the altitude in the HMA. 3) The contents of NN in water of marshes increased with the increase of longitude and latitude across the HMA. Water depth and water temperature were drivers of this distribution. 4) The content of AN in water of marshes increased with the increase of longitude across the HMA. However, the distribution of AN could not be well explained by the natural and socio-economic factors.