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...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。展开更多
Due to increasing global demand for crop production and energy use, more and more reactive nitrogen（Nr） has been generated and emitted to the environment. As a result, global atmospheric nitrogen（N） deposition has...Due to increasing global demand for crop production and energy use, more and more reactive nitrogen（Nr） has been generated and emitted to the environment. As a result, global atmospheric nitrogen（N） deposition has tripled since the industrial revolution and the ecological environment and human health have been harmed. In this study, we measured dry and wet/bulk N deposition from July 2013 to December 2015 in a semi-arid grassland of Duolun County, Inner Mongolia, China. The samples of dry and wet/bulk N deposition were collected monthly with a DELTA（DEnuder for Long Term Atmospheric sampling） system and with Gradko passive samplers and a precipitation gauge. The measured results show that the annual mean concentrations of NH_3, NO_2, HNO_3, particulate NH_4~＋（pNH_4~＋） and particulate NO_3^-（pNO_3^-） in atmosphere were 2.33, 1.90, 0.18, 1.42 and 0.42 μg N/m3, respectively, and that the annual mean volume-weighted concentrations of NH_4~＋-N and NO_3^--N in precipitation were 2.71 and 1.99 mg N/L, respectively. The concentrations of Nr components（including NH_3, NO_2, HNO_3, p NH_4~＋, pNO_3^-, NH_4~＋-N and NO_3^--N） exhibited different seasonal variations. Specifically, NO_2 and HNO_3 exhibited higher concentrations in autumn than in summer, while the other Nr components（NH_3, pNH_4~＋, pNO_3^-, NH_4~＋-N and NO_3^--N） showed the highest values in summer. Based on measured concentrations of Nr components and their deposition velocities estimated using the GEOS-Chem global atmospheric chemical transport model, the calculated annual mean dry deposition fluxes were 3.17, 1.13, 0.63, 0.91 and 0.36 kg N/（hm^2·a） for NH_3, NO_2, HNO_3, p NH_4~＋ and pNO_3^-, respectively, and the calculated annual mean wet/bulk deposition fluxes were 5.37 and 3.15 kg N/（hm^2·a） for NH_4~＋-N and NO_3^--N, respectively. The estimated annual N deposition（including dry N deposition and wet/bulk N deposition） reached 14.7 kg N/（hm^2·a） in grassland of Duolun County, approaching to the upper limit of the N critical load（10–15 kg N/（hm^2·a））. Dry and wet/bulk deposition fluxes of all Nr components（with an exception of HNO_3） showed similar seasonal variations with the maximum deposition flux in summer and the minimum in winter. Reduced Nr components（e.g., gaseous NH_3 and p NH_4~＋ in atmosphere and NH_4~＋-N in precipitation） dominated the total N deposition at the sampling site（accounted for 64% of the total N deposition）, suggesting that the deposited atmospheric Nr mainly originated from agricultural activities. Considering the projected future increases in crop and livestock production in Inner Mongolia, the ecological and human risks to the negative effects of increased N deposition could be increased if no mitigation measures are taken.展开更多
文摘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。
基金financially supported by the National Key R&D Program of China (2017YFC0210101, 2014CB954202)the National Natural Science Foundation of China (41425007)
文摘Due to increasing global demand for crop production and energy use, more and more reactive nitrogen（Nr） has been generated and emitted to the environment. As a result, global atmospheric nitrogen（N） deposition has tripled since the industrial revolution and the ecological environment and human health have been harmed. In this study, we measured dry and wet/bulk N deposition from July 2013 to December 2015 in a semi-arid grassland of Duolun County, Inner Mongolia, China. The samples of dry and wet/bulk N deposition were collected monthly with a DELTA（DEnuder for Long Term Atmospheric sampling） system and with Gradko passive samplers and a precipitation gauge. The measured results show that the annual mean concentrations of NH_3, NO_2, HNO_3, particulate NH_4~＋（pNH_4~＋） and particulate NO_3^-（pNO_3^-） in atmosphere were 2.33, 1.90, 0.18, 1.42 and 0.42 μg N/m3, respectively, and that the annual mean volume-weighted concentrations of NH_4~＋-N and NO_3^--N in precipitation were 2.71 and 1.99 mg N/L, respectively. The concentrations of Nr components（including NH_3, NO_2, HNO_3, p NH_4~＋, pNO_3^-, NH_4~＋-N and NO_3^--N） exhibited different seasonal variations. Specifically, NO_2 and HNO_3 exhibited higher concentrations in autumn than in summer, while the other Nr components（NH_3, pNH_4~＋, pNO_3^-, NH_4~＋-N and NO_3^--N） showed the highest values in summer. Based on measured concentrations of Nr components and their deposition velocities estimated using the GEOS-Chem global atmospheric chemical transport model, the calculated annual mean dry deposition fluxes were 3.17, 1.13, 0.63, 0.91 and 0.36 kg N/（hm^2·a） for NH_3, NO_2, HNO_3, p NH_4~＋ and pNO_3^-, respectively, and the calculated annual mean wet/bulk deposition fluxes were 5.37 and 3.15 kg N/（hm^2·a） for NH_4~＋-N and NO_3^--N, respectively. The estimated annual N deposition（including dry N deposition and wet/bulk N deposition） reached 14.7 kg N/（hm^2·a） in grassland of Duolun County, approaching to the upper limit of the N critical load（10–15 kg N/（hm^2·a））. Dry and wet/bulk deposition fluxes of all Nr components（with an exception of HNO_3） showed similar seasonal variations with the maximum deposition flux in summer and the minimum in winter. Reduced Nr components（e.g., gaseous NH_3 and p NH_4~＋ in atmosphere and NH_4~＋-N in precipitation） dominated the total N deposition at the sampling site（accounted for 64% of the total N deposition）, suggesting that the deposited atmospheric Nr mainly originated from agricultural activities. Considering the projected future increases in crop and livestock production in Inner Mongolia, the ecological and human risks to the negative effects of increased N deposition could be increased if no mitigation measures are taken.
