Nitrogen isotope fractionation and geological nitrogen cycle

轻稳定同位素已成为行星和地球科学中追踪物质来源和监测（生物）地球化学过程的常规和强大工具。例如，碳同位素已被用于研究地球上不同时空尺度的碳循环。这一努力极大地促进了我们对地幔、地壳、特别是大气之间的演化和相互作用的理解，其中温室气体二氧化碳的水平直接影响着气候和环境。与之形成鲜明对比的是，尽管氮的几种种类（NH3、N2O、N2）也起到温室气体的作用，但人们对氮的循环仍知之甚少。氮是地球所有储集层中与碳同等重要的成分。这主要是由于(1)对氮同位素在控制氮转移的关键过程中的作用和不同压力-温度条件下的定位认识不足；(2)对不同储层氮性质界定的边界条件约束不足。

Light stable isotopes have become a routine and robust tool to trace material sources and monitor (bio)geochemical processes in planetary and geosciences. For example, carbon isotopes have been used to examine the carbon cycle in various temporal and spatial scales on the Earth. This effort has significantly advanced our understanding of the evolution of and interaction between the Earth's mantle, crust, and particularly atmosphere, in which the level of greenhouse gas CO2 directly impacts the climate and environment. In striking contrast, the cycle of nitrogen, a component equally important as carbon in all Earth's reservoirs, is still poorly understood even though several of its species (NH3, N2O, N2) also act as greenhouse gases. This has been mainly attributed to (1) the poor knowledge of nitrogen isotope effects in key processes controlling nitrogen transfer and siting at different pressure-temperature conditions and (2) poorly constrained boundary conditions to define the nitrogen properties of different reservoirs.