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

自1950年以来，全球人口翻了一番，这主要是由于绿色革命，其中农业化肥使用量增加了10倍，粮食产量翻了一番。这些耕作方法也使土壤磷（P）含量增加了200%或更多，并在许多哨兵生态系统中创造了条件，其中农业土壤现在饱和了P，并将保持数百年，并为淡水提供过量的P。在这些条件下，氮（N）和光能（E）的供应似乎调节湖泊生产，水质退化，以及有毒藻华的发展。 不幸的是，由于自1970年以来，氮肥也增加了15倍，而且其中一半以上的氮是以尿素的形式加入的，尿素是一种选择性促进有毒蓝细菌生长的氮的化学形式，因此，农业的持续发展有可能导致有毒和可能致癌的藻类在大陆范围内爆发。 鉴于约10亿人已经缺乏清洁水，我们寻求大量资金来预测这些变化对加拿大和世界各地的人类和淡水的影响。

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.