Development of a Coupled Global Circulation/Adaptive Food Web Model to Explain Carbon Cycling in the Ocean

这项研究将发展一个食物网模型，该模型可用于预测出口产量，并表征出口到海洋内部的碳的性质。该模型将类似于1999年在科罗拉多州基斯顿举行的食物网综合与建模（SMP）研讨会上开发的概念性食物网模型。在该模型中，浮游植物被设想为由五个功能基团组成，小型浮游植物如聚藻球菌和原绿球藻、硅藻、球石藻、Phaeocystis和固氮生物。据推测，以这种方式划分浮游植物是必要的，以解释出口比例对温度和初级生产的依赖，解释出口碳在碳酸钙、颗粒有机碳和溶解有机碳之间的分配，并考虑到影响颗粒碳沉降和再矿化速率的各种压舱方法（粪便颗粒、碳酸钙和二氧化硅）。该模型的一个显著特征是假设开放海洋生物群落适应环境条件的方式倾向于最大限度地提高群落进化的稳态条件的稳定性。同样的假设先前已经用一个更简单的食物网模型进行了测试，在这个模型中，浮游植物被设想为只由两个功能群组成，小浮游植物和大浮游植物。先前的模型是在SMP第一阶段的资助下开发的，它的成功为将相同的方法扩展到包含五个功能浮游植物群的更复杂的模型提供了动力。据推测，一个稳定的海洋物理-生物耦合模型将要求生物成分具有适应性。关于出口生产，该模型将处理的具体问题包括：有多少有机碳以溶解有机碳（DOC）的形式输出，有多少以颗粒碳（PC）的形式输出。在PC出口中，有多少是颗粒有机碳（POC），有多少是碳酸盐碳（CC） ？出口的POC在多大程度上由二氧化硅和/或碳酸盐压舱，或通过掺入封装的粪便颗粒进行隔离？该模型的时间依赖版本可在以后的日期纳入GCM。

This research will be on the development of a food web model that can be used to predict export production and to characterize the nature of the carbon exported to the interior of the ocean. The model will be similar to the food web model developed conceptually at the 1999 Synthesis and Modeling (SMP) food web work-shop in Keystone, Colorado. In the model phytoplankton are envisioned as consisting of five functional groups, small phytoplankton such as Synechococcus and Prochlorococcus, diatoms, coccolithophores, Phaeocystis, and nitrogen fixers. Division of the phytoplankton in this manner is hypothesized to be necessary to explain the dependence of export ratios on temperature and primary production, to account for the allocation of exported carbon between calcium carbonate, particulate organic carbon, and dissolved organic carbon, and to take into account various methods of ballasting (fecal pellets, calcium carbonate, and silica) that influence the sinking and remineralisation rates of particulate carbon. A distinguishing characteristic of the model is the assumption that open ocean biological communities adapt to environmental conditions in a way that tends to maximize the stability of the steady state condition toward which the communities evolve. This same hypothesis has previously been tested with a simpler food web model in which the phytoplankton are envisioned as consisting of only two functional groups, small and large phytoplankton. The success of that previous model, which was developed with funding from the first phase of the SMP, has provided the motivation for extending this same approach to the more complex model with five functional phytoplankton groups. It is hypothesized that a stable coupled physical-biological model of the ocean will require that the biological component be adaptive. With respect to export production, specific questions to be addressed with the model will include the following:1. How much of the organic carbon is exported as dissolved organic carbon (DOC) and how much as particulate carbon (PC)2. Of the PC export, how much is exported as particulate organic carbon (POC) and how much as carbonate carbon (CC)3. To what extent is the exported POC ballasted by silica and/or carbonate or sequestered by incorporation into encapsulated fecal pelletsA time-dependent version of the model may be incorporated into a GCM at a later date.