JGOFS/SMP: Data-based Models of Food Web Structure and Export Flux

浮游生物群落结构和出口流量的数据模型过去十年间联合全球浮游生物监测系统的深入调查表明，物理化学环境强迫、浮游生物群落结构和碳生产(再矿化或出口)的命运之间存在密切联系。然而，这些关系在现有的浮游生物食物网络模型中被粗略地描绘出来。目前尚不清楚需要多少关于大小和分类组成的信息才能进行充分的模型预测，也不清楚不同水团中的群落动态和生物地球化学通量通过共同的组织原则和数量关系在多大程度上联系在一起。拟议研究的总体目标是有助于从机制上理解调控真光带生产和出口碳及相关生物活性物质的因素。为实现这一目标，PIS将开发和评估基于数据的热带/亚热带开阔海洋生态系统浮游生物群落结构和出口通量模型。该项目将侧重于热带和亚热带海洋，这些区域在联合全球海洋观测系统进程和时间序列研究(EqPac、阿拉伯海、HOT、BATS)中具有最强的代表性，目前在成熟的数据库和辅助实验研究方面开发得最多。具体目标是：1)开发浮游生物群落结构和营养相互作用的数据约束表示；2)构建夏威夷海洋时间序列(HOT)站点和赤道太平洋铁扰动(IronEx II)的时间浮游生物群落动态和相关生物地球化学通量的模式；3)比较和测试简单的参数化方案，用于低营养层相互作用和输出通量，用于3-D耦合模式；4)开发一个包括营养供应(阿拉伯海)和铁限制(赤道太平洋)的适当响应的一般热带海洋模式；5)研究在计算密集型全球环流模式(GCM)中用于预测生物现实反应的模型结构和策略。根据在不同热带海洋生态系统中观察到的种群和加工速率的相似性，PIS假设这些数据将适合于用具有共同结构和参数的一般热带海洋模式来表示。为了调查在全球模型中捕捉基本生物现实所需的最低复杂程度，他们将从统计上检查相互关联的模型谱，所有模型都校准到共同的数据集，但结构复杂性不同。

Data-Based Models of Plankton Community Structure and Export FluxIntensive JGOFS investigations over the past decade have indicated strong links among physical-chemical environmental forcing, plankton community structure, and the fate of carbon production (remineralization or export). However, these relationships are crudely portrayed in existing plankton food web models. It is presently unclear how much information on size and taxonomic composition is needed for adequate model predictions and to what extent community dynamics and biogeochemical fluxes in different water masses are linked by common organizational principles and quantitative relationships.The overall goal of the proposed research is to contribute to the mechanistic understanding of the factors that regulate "euphotic zone production and export of carbon and related biologically active substances". To accomplish this, the PIs will develop and evaluate data-based models of plankton community structure and export flux for tropical/subtropical open-ocean ecosystems. This project will focus on the tropical and subtropical oceans, areas most strongly represented in JGOFS Process and Time-series studies (EqPac, Arabian Sea, HOT, BATS) and presently most developed in terms of mature databases and supporting experimental studies. The specific objectives are: 1) to develop data-constrained representations of planktonic community structure and trophic interactions; 2) to construct models of temporal plankton community dynamics and associated biogeochemical fluxes at the Hawaii Ocean Time-series (HOT) site and following iron perturbation in the equatorial Pacific (IronEx II); 3) to compare and test simple parameterizations, for lower trophic level interactions and export fluxes for use in 3-D coupled models; 4) to develop a general tropical ocean model that includes appropriate responses to nutrient supply (Arabian Sea) and iron-limitation (Equatorial Pacific); and 5) to examine model structures and strategies for predicting biologically realistic responses in computationally intensive Global Circulation Models (GCMs). Based on observed similarities in the stocks and process rates in diverse tropical oceanic ecosystems, the PIs hypothesize that the data will lend themselves to representation in a general tropical ocean model with common structure and parameters. To investigate the minimum level of complexity required to capture essential biological realities in global models, they will statistically examine an interrelated spectrum of models, all calibrated to common data sets but differing in structural complexity.