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

浮游生物群落结构和输出通量的基于数据的模型 过去十年中 JGOFS 的密集调查表明，物理化学环境强迫、浮游生物群落结构和碳生产（再矿化或输出）的命运之间存在密切联系。 然而，现有的浮游生物食物网模型粗略地描述了这些关系。 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适当的模型预测，以及不同水体中的群落动态和生物地球化学通量在多大程度上通过共同的组织原则和定量关系联系起来。拟议研究的总体目标是有助于从机制上理解调节“光强区碳和相关生物活性物质的生产和输出”的因素。 为了实现这一目标，PI 将开发和评估基于数据的热带/亚热带公海生态系统浮游生物群落结构和出口通量模型。 该项目将重点关注热带和亚热带海洋，这些区域在 JGOFS 过程和时间序列研究（EqPac、阿拉伯海、HOT、BATS）中代表性最强，并且目前在成熟数据库和支持实验研究方面最发达。 具体目标是：1）开发浮游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后的时间浮游生物群落动态和相关生物地球化学通量模型（IronEx II）； 3) 比较和测试简单的参数化，以实现较低营养级的相互作用并输出通量以用于 3-D 耦合模型； 4) 开发一个通用的热带海洋模型，其中包括对养分供应（阿拉伯海）和铁限制（赤道太平洋）的适当反应； 5) 检查模型结构和策略，以预测计算密集型全球循环模型 (GCM) 中的生物学真实反应。 根据观察到的不同热带海洋生态系统中种群和加工速率的相似性，PI 假设这些数据将有助于在具有共同结构和参数的一般热带海洋模型中表示。 为了研究在全球模型中捕获基本生物现实所需的最低复杂性水平，他们将统计检查一系列相互关联的模型，所有模型都根据通用数据集进行校准，但结构复杂性有所不同。

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.