Degradation and destablization of lake ecosystems by anthropogenic nitrogen: a new paradigm for future lake eutrophication

自1950年以来，全球人口已经翻了一番，这主要是由于绿色革命，其中农业肥料使用量增加了10倍，粮食产量翻了一番。这些耕作方式还使土壤磷(P)含量提高了200%或更多，并在许多哨兵生态系统中创造了条件，在这些生态系统中，农业土壤现在磷饱和，并将在几个世纪内保持这种状态，并向淡水提供过量的磷。在这些条件下，氮(N)和光能(E)的供应似乎调节了湖泊产量、水质退化和有毒藻华的发展。不幸的是，由于氮肥自1970年以来也增加了15倍，并且由于其中一半以上的氮以尿素的形式添加，尿素是氮的一种化学形式，可以选择性地促进有毒的蓝藻，因此持续的农业发展可能会导致大陆规模的有毒和可能致癌的藻类爆发。鉴于约有10亿人已经缺乏清洁水，我们寻求大量资金，以发展对这些变化对加拿大和全世界人类和淡水的后果的预测性理解。

Global human population has doubled since 1950, largely due to the green revolution in which a 10-fold increase in agricultural application of fertilizer has doubled food production. These farming practices have also raised soil phosphorus (P) content by 200% or more and have created conditions in many sentinel ecosystems in which agricultural soils are now saturated with P, will remain so for centuries, and supply freshwaters with excess P. Under these conditions, supplies of nitrogen (N) and light energy (E) appear to regulate lake production, water quality degradation, and the development of toxic algal blooms. Unfortunately, because N fertilization has also increased 15-fold since 1970, and because more than half of this N is added as urea, a chemical form of N which selectively promotes toxic cyanobacteria, there exists the possibility that continued agricultural development will lead to continental-scale outbreaks of toxic and possibly carcinogenic algae. Given that ~1 billion people already lack clean water, we seek substantial funding to develop a predictive understanding of the consequences of these changes for humans and freshwaters throughout Canada and the world.