Nutrient Spiralling in Streams: Implications for Nutrient Limitation and Invertebrate Activity
Nutrient Spiralling in Streams: Implications for Nutrient Limitation and Invertebrate Activity
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DOI：
10.1086/284017
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发表时间：
1982-11
期刊：
影响因子：
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通讯作者：
J. Newbold;R. O'Neill;J. Elwood;W. V. van Winkle
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文献类型：
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作者：
J. Newbold;R. O'Neill;J. Elwood;W. V. van Winkle
河流中的营养物质循环与下游运输一起发生，这是一个空间分布的过程，被称为螺旋式。当营养物通过下游时，其再利用的强度可以用营养物原子完成一个（抽象的）循环所需的水流长度来量化;这个距离被称为螺旋长度。我们的模型为稳态螺旋限制营养素预测，大多数的下游运输的营养素发生在颗粒或不可用的形式时，营养素限制是严重的，在这种情况下，颗粒的可运输性是螺旋长度的一个主要决定因素。另一方面，当养分限制是缓和的密度依赖性机制，在溶解相的运输占主导地位，颗粒的可运输性螺旋长度的影响不大。通过考虑无脊椎动物消费者对再生、可运输性和营养物质吸收的影响，研究了无脊椎动物消费者在控制螺旋上升中的潜在作用。放牧和滤食性的功能过程似乎最有可能缩短螺旋长度时，营养限制是严重的，而切碎的过程更有可能缩短螺旋长度时，营养限制是弱的。在某些情况下，可能存在消费者活动水平，在该水平下螺旋长度被最小化。
Nutrient cycling in streams occurs in conjunction with downstream transport as spatially distributed process that has been termed spiralling. The intensity of reutilization of nutrients as they pass downstream can be quantified in terms of the length of stream required for a nutrient atom to complete one (abstract) cycle; this distance is termed the spiralling length. Our model for steady-state spiralling of a limiting nutrient predicts that most of the downstream transport of nutrient occurs in particulate or unavailable form when nutrient limitation is severe; in this case, transportability of particulates is a major determinant of spiralling length. On the other hand, when nutrient limitation is moderated by density-dependent mechanisms, transport in the dissolved phase dominates, and transportability of particles has little influence on spiralling length. The potential role of invertebrate consumers in controlling spiralling was investigated by considering their influence on regeneration, transportability, and uptake of nutrients. Functional processes of grazing and filter feeding appear most likely to shorten spiralling length when nutrient limitation is severe, while the process of shredding is more likely to shorten spiralling length when nutrient limitation is weak. In some cases there may be levels of consumer activity at which spiralling length is minimized.