搜索结果: 1-7 共查到“环境科学技术 15N”相关记录7条 . 查询时间(0.124 秒)
中国科学院南京土壤研究所专利：15N示踪硝化-反硝化作用气体产物的前处理系统
为定量化识别北京城区河流硝酸盐来源,采用δ15 N-NO3-和δ18O-NO3-双同位素示踪法对北京城区河流河水硝酸盐的氮氧稳定同位素组成进行分析,利用稳定同位素混合模型追溯北京城区河流硝酸盐来源,并评估各污染源的贡献率.结果表明:1北京河流无机氮污染以硝酸盐氮(NO3--N)污染为主,且河流下游硝酸盐氮污染较为严重.2北京城区地表河流δ15 N-NO3-值范围为6.26‰~24.94‰,δ18O...
Assessing nonpoint-source nitrogen loading and nitrogen fixation in lakes using δ15N and nutrient stoichiometry
Assessing nonpoint-source nitrogen loading nitrogen fixation lakes using δ15N nutrient stoichiometry
2014/4/3
Runoff from human-dominated watersheds has greatly altered nitrogen (N) and phosphorus (P) cycling in lakes. Nutrients from human sources are distinct from those from undisturbed ecosystems in several...
Environmental perturbation effects on baseline δ15N values and zooplankton trophic flexibility in the southern California Current Ecosystem
Environmental perturbation baseline δ15N values zooplankton trophic flexibility southern California Current Ecosystem
2014/4/2
Nitrogen isotopic compositions of zooplankton in the California Current Ecosystem (CCE) are known to vary over inter-annual scales of climate variability, but the extent to which those changes are dri...
Nitrate removal in stream ecosystems measured by 15N addition experiments: Denitrification
Nitrate removal stream ecosystems measured 15N addition experiments Denitrification
2014/4/18
We measured denitrification rates using a field 15NO3- tracer-addition approach in a large, cross-site study of nitrate uptake in reference, agricultural, and suburban-urban streams. We measured denit...
Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake
Nitrate removal stream ecosystems measured 15N addition experiments Total uptake
2014/4/18
We measured uptake length of 15NO3- in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO3- uptake length. As part of the ...
污染含水层微生物除氮过程15N标识实验研究
微生物 除氮污染 含水层
2008/8/6
该项目详细综述了多孔介质中利用微生物净化污染介质过程中，微生物作用下的物质转化及其动力学过程，主要是针对目前研究多孔介质中生物除氮过程主要由实验和常规分析定量确定NH_4^+→NO_2^-→NO_3^-的转化和迁移过程，对氮素在细菌和含氮化合物间的转移过程研究的不足，全面研究氮素在微生物和化合物中的迁移形式。首次进行，对15N适应的人工脱氮微生物从土壤中筛选、分离和驯化培养研究，初步选定了适应污染...