Poulin Francis J, Franks Peter J S
Department of Applied Mathematics , University of Waterloo , Waterloo, ON , Canada N2L 3G1.
J Plankton Res. 2010 Aug;32(8):1121-1130. doi: 10.1093/plankt/fbp145. Epub 2010 Jan 24.
Here we present a nutrient-phytoplankton-zooplankton (NPZ) model that has arbitrary size-resolution within the phytoplankton- and zooplankton-state variables. The model assumes allometric scaling of biological parameters. This particular version of the model (herbivorous zooplankton only) has analytical solutions that allow efficient exploration of the effects of allometric dependencies of various biological processes on the model's equilibrium solutions. The model shows that there are constraints on the possible combinations of allometric scalings of the biological rates that will allow ecosystems to be structured as we observe (larger organisms added as the total biomass increases). The diversity (number of size classes occupied) of the ecosystem is the result of simultaneous bottom-up and top-down control: resources determine which classes can exist; predation determines which classes do exist. Thus, the simultaneous actions of bottom-up and top-down controls are essential for maintaining and structuring planktonic ecosystems. One important conclusion from this model is that there are multiple, independent ways of obtaining any given biomass spectrum, and that the spectral slope is not, in and of itself, very informative concerning the underlying dynamics. There is a clear need for improved size-resolved field measurements of biological rates; these will both elucidate biological processes in the field, and allow strong testing of size-structured models of planktonic ecosystems.
在此，我们提出了一个营养物-浮游植物-浮游动物（NPZ）模型，该模型在浮游植物和浮游动物状态变量内具有任意大小分辨率。该模型假设生物参数呈异速生长缩放。此特定版本的模型（仅食草浮游动物）具有解析解，可有效探究各种生物过程的异速生长依赖性对模型平衡解的影响。该模型表明，生物速率的异速生长缩放的可能组合存在限制，这些限制将使生态系统能够如我们所观察到的那样构建（随着总生物量增加，更大的生物体被添加进来）。生态系统的多样性（所占据的大小类别的数量）是自下而上和自上而下控制同时作用的结果：资源决定哪些类别可以存在；捕食决定哪些类别确实存在。因此，自下而上和自上而下控制的同时作用对于维持和构建浮游生态系统至关重要。该模型的一个重要结论是，存在多种独立的方式来获得任何给定的生物量谱，并且谱斜率本身对于潜在动态并不是非常有信息量。显然需要改进对生物速率的大小分辨现场测量；这些测量将既能阐明现场的生物过程，又能对浮游生态系统的大小结构模型进行有力检验。
