Nitrogen transformations differentially affect nutrient‐limited primary production in lakes of varying trophic state
Nitrogen transformations differentially affect nutrient‐limited primary production in lakes of varying trophic state
复制标题
DOI：
10.1002/lol2.10109
复制
发表时间：
2019-05
影响因子：
7.8
通讯作者：
J. Scott;M. J. McCarthy;H. Paerl
中科院分区：
文献类型：
--
作者：
J. Scott;M. J. McCarthy;H. Paerl
尽管直接证据有限，但湖泊“进化”磷(P)限制的概念在湖泊学中一直存在。在这里，我们开发了一个简单的模型来广泛描述湖泊中氮(N)相对于P的盈余和亏损，并将这种失衡的程度与通过生物N转化而获得和损失的N的估计进行了比较。该模型表明，美国大约一半的贫营养湖泊存在化学计量氮亏缺，但分别有72%-89%的富营养化湖泊和重度富营养化湖泊存在类似的氮亏缺。尽管活性氮似乎在最富营养化的湖泊中积累，但净反硝化作用在产量更高的湖泊中持续存在N的亏缺。生产性湖泊无论缺氮与否，都通过生物氮素转化输出活性氮。缺乏通过固氮积累的氮，突出了现代富营养化管理方法的必要性，其重点是减少外部总营养负荷，包括N和P。
The concept of lakes “evolving” phosphorus (P) limitation has persisted in limnology despite limited direct evidence. Here, we developed a simple model to broadly characterize nitrogen (N) surpluses and deficits, relative to P, in lakes and compared the magnitude of this imbalance to estimates of N gains and losses through biological N transformations. The model suggested that approximately half of oligotrophic lakes in the U.S.A. had a stoichiometric N deficit, but 72–89% of eutrophic and hypereutrophic lakes, respectively, had a similar N deficit. Although reactive N appeared to accumulate in the most oligotrophic lakes, net denitrification perpetuated the N deficit in more productive lakes. Productive lakes exported reactive N via biological N transformations regardless of their N deficit. The lack of N accumulation through N fixation underscores the need for a modern eutrophication management approach focused on reducing total external nutrient loads, including both N and P.