Nitrogen limitation on land and in the sea: How can it occur?
Nitrogen limitation on land and in the sea: How can it occur?
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DOI：
10.1007/bf00002772
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发表时间：
1991
期刊：
影响因子：
4
通讯作者：
P. Vitousek;R. Howarth
中科院分区：
文献类型：
--
作者：
P. Vitousek;R. Howarth
在陆地和海洋生态系统中，氮对净初级生产力的限制是一个令人困惑的问题;似乎在氮受到限制的地方，固氮菌应该具有很大的竞争优势，而它们的活动反过来应该逆转限制。然而，有大量的证据表明，氮限制净初级生产的大部分时间在大多数陆地生物群系和许多海洋ecosystems.We研究如何氮循环的地球化学可能会导致限制发展，以及如何氮限制可能会持续作为一个后果的过程，防止或减少固氮。有利于氮限制的生物地球化学机制包括：氮跨越生态系统边界的大量流动性，这有利于“源”生态系统中的氮限制-特别是在沉积物和土壤中反硝化作用很重要的地方，或者在火灾频繁的陆地生态系统中;氮与磷在生物化学上的差异（碎屑N主要是碳键，碎屑P主要是酯键），这有利于在分解缓慢的地方发展氮限制，并允许从氮限制到生产者的正反馈的发展，减少其碎屑的分解，并减少氮的可用性;以及其他更专门的，但可能同样重要的过程。这些包括：对定殖或固氮活性的能量限制;固氮或固定的另一种营养素（磷，钼，铁）的限制-这将是最终的限制因素净初级生产力;其他物理和生态mechanism.The可能的重要性，这些和其他过程进行了讨论，为广泛的陆地，淡水和海洋生态系统。
The widespread occurrence of nitrogen limitation to net primary production in terrestrial and marine ecosystems is something of a puzzle; it would seem that nitrogen fixers should have a substantial competitive advantage wherever nitrogen is limiting, and that their activity in turn should reverse limitation. Nevertheless, there is substantial evidence that nitrogen limits net primary production much of the time in most terrestrial biomes and many marine ecosystems.We examine both how the biogeochemistry of the nitrogen cycle could cause limitation to develop, and how nitrogen limitation could persist as a consequence of processes that prevent or reduce nitrogen fixation. Biogeochemical mechansism that favor nitrogen limitation include:the substantial mobility of nitrogen across ecosystem boundaries, which favors nitogen limitation in the “source” ecosystem — especially where denitrification is important in sediments and soils, or in terrestrial ecosystems where fire is frequent;differences in the biochemistry of nitrogen as opposed to phosphorus (with detrital N mostly carbon-bonded and detrital P mostly ester-bonded), which favor the development of nitrogen limitation where decomposition is slow, and allow the development of a positive feedback from nitrogen limitation to producers, to reduced decomposition of their detritus, and on to reduced nitrogen availability; andother more specialized, but perhaps no less important, processes.A number of mechanisms could keep nitrogen fixation from reversing nitrogen limitation. These include:energetic constraints on the colonization or activity of nitrogen fixers;limitation of nitrogen fixers or fixation by another nutrient (phosphorus, molybdenum, or iron) — which would then represent the ultimate factor limiting net primary production;other physical and ecological mechanisms.The possible importance of these and other processes is discussed for a wide range of terrestrial, freshwater, and marine ecosystems.