The global nitrogen cycle: changes and consequences
The global nitrogen cycle: changes and consequences
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DOI：
10.1016/s0269-7491(98)80010-9
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发表时间：
1998-01-01
影响因子：
8.9
通讯作者：
Galloway, JN
中科院分区：
文献类型：
--
作者：
Galloway, JN
在没有人类活动的情况下，生物固氮是活性氮的主要来源，在大陆上提供约 90-130 Tg N 年(-1) (Tg = 10(12) g)。人类活动通过能源生产、化肥生产和农作物（例如豆类、水稻）种植，额外固定了大约 150 Tg N 年(-1)。一些人为氮汇已经被估计（例如，大气中一氧化二氮的积累；沿海海洋的损失），然而，由于其他汇的大小的不确定性（例如，地下水、土壤或植被中的滞留或氮的反硝化），人类固定的氮可能有很大一部分被遗漏了。虽然我们知道 N 在环境中积累，但我们不知道积累速度。由于过量的氮对人类、生态系统和大气产生多种影响，及其级联性质（即，一个氮原子在转化为不同的氮物种时可以产生大量不同的影响），这种知识的缺乏是不幸的。社会可用于减少人类活动所动员的氮量的选择有限，因为实际上存在氮的必要性——它是粮食生产所必需的。随着人口和人均食品（特别是动物产品）消费量的增加，未来越来越多的氮将从非反应形式转化为反应形式。在欠发达地区尤其如此。
In the absence of human activities, biological N fixation is the primary source of reactive N, providing about 90-130 Tg N year(-1) (Tg = 10(12) g) on the continents. Human activities have resulted in the fixation of an additional similar to 150 Tg N year(-1) by energy production, fertilizer production, and cultivation of crops (e.g., legumes, rice). Some sinks of anthropogenic N have been estimated (e.g., N2O accumulation in the atmosphere; loss to coastal oceans), however due to the uncertainty around the magnitude of other sinks (e.g., retention in groundwater, soils, or vegetation or denitrification to N,) a possibly large portion of the N fixed by humans is missing. While we know that N is accumulating in the environment, we do not know the rate of accumulation. Due to the myriad of effects of excess N on humans, ecosystems, and the atmosphere, and their cascading nature (i.e., one atom of N can have a large number of different effects as it is transformed to different N species), this lack of knowledge is unfortunate. There are limited options available to society to reduce the amount of N mobilized by human action because there is, in effect, a N imperative - it is required for food production. As population and per capita consumption of food (especially animal products) increase, more and more N will be converted from unreactive to reactive forms in the future. This is especially true in less developed regions.