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

这项研究将开发一个食物网络模型，该模型可用于预测出口产量，并表征输出到海洋内陆的碳的性质。该模型将类似于在科罗拉多州基斯通的1999年合成和建模(SMP)食物网络工作商店从概念上开发的食物网络模型。在该模型中，浮游植物被设想为由五个功能基团组成，小型浮游植物如聚球藻和原氯球菌、硅藻、球藻、棕囊藻和固氮剂。假设有必要以这种方式划分浮游植物，以解释出口比率对温度和初级生产力的依赖，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，并考虑影响颗粒碳沉降率和再矿化率的各种压载方法(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的海洋生物群落以一种倾向于最大化群落进化所向的稳定状态的稳定性的方式适应环境条件。同样的假设之前已经在一个更简单的食物网模型中得到了验证，在这个模型中，浮游植物被设想为只由两个功能群组成，即小浮游植物和大浮游植物。前一个模型的成功是由SMP第一阶段提供资金开发的，它为将同样的方法扩展到有五个功能浮游植物组的更复杂的模型提供了动力。人们假设，一个稳定的海洋物理-生物耦合模型将要求生物组成部分具有适应性。关于出口生产，模型要解决的具体问题包括：1.有多少有机碳作为溶解有机碳(DOC)出口，有多少作为颗粒碳(PC)出口2.在PC出口中，有多少作为颗粒有机碳(POC)出口，多少作为碳酸盐碳(CC)出口3.出口的POC在多大程度上是由二氧化硅和/或碳酸盐压载的，还是通过并入封装的粪便颗粒来隔离的该模型的一个随时间变化的版本可能在以后被纳入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.