Development, Analysis, and Implementation of Computationally Efficient Models for Resolving CEllular and COMmunity Composition of Plankton (CECOMP)

海洋和海洋系统中的浮游植物在全球生物地球化学循环中发挥着重要作用。耦合地球系统模型对估算不同尺度下生态系统的未来和假设状态很有用，它使用了浮游生物的生长、输出和碳和其他元素的营养转移的参数化。通常，这些参数化要么完全忽略，要么依赖于底层过程的过于简化的表示。因此，叶绿素、碳、氮、磷和其他与浮游植物生物量结合的相关元素的比率的可变性要么是错误的，要么是基于启发式公式估计的，这些公式的行为可能在参数拟合条件的范围之外变得可疑。在这个项目中，我们的目标是开发模型组件，通过以计算高效的方式计算适应过程，可以改善藻类生长和组成的表示。这些模型组件将被模块化地设计，这样它们就可以很容易地与现有的浮游生物模型相结合。我们将评估这些模型组件的效用：1)理解连接生态生理和非生物元素比例的机制，2)减少对特定地点参数调整的需求，因此3)增强模型的预测能力。为了达到这些目标，我们将项目组织成两组工作包：1)在理想设置中开发模型并分析其行为；2)在北太平洋和北海海岸系统的现实三维模型设置中实现。在第一组中详细阐述的理想主义设置将捕捉到在第二组中要研究的特定研究区域中观察到的特征，以便在每个组中获得的发现将与其他组相关。因此，本项目将协同结合这两种经常单独使用的互补方法。

Phytoplankton in oceans and marine systems play important roles in global biogeochemical cycles. Coupled earth system models, which are useful for estimating future and hypothetical states of ecosystems at various scales, use parameterizations of growth, export, and trophic transfer of carbon and other elements bound to plankton. Often, these parameterizations either completely ignore, or rely on oversimplified representations of underlying processes. As a result, the variability in the ratios of chlorophyll, carbon, nitrogen, phosphorus and other relevant elements bound to phytoplankton biomass are either misrepresented, or estimated based on heuristic formulations, behavior of which may become questionable outside the range of parameter fitting conditions. In this project, our objective is to develop model components that can improve the representation of algal growth and composition by accounting for acclimation processes in a computationally efficient manner. Those model components will be designed modularly, such that they can be easily coupled with existing plankton models. We will assess the utility of these model components for: i) understanding the mechanisms linking ecophysiology and abiotic elemental ratios, ii) reducing the need for site specific parameter tuning, and hence iii) enhancing predicitive capacity of the models. For reaching these objectives, we have organized the project into two groups of work packages: 1) Model development and analysis of their behaviors in idealized setups; 2) Implementation in realistic 3-D model setups for the North Pacific and North Sea coastal systems. The idealistic setups to be elaborated in the first group will capture the characteristic features observed in the specific study regions to be studied in the second group, such that the findings obtained within each group will be relevant for the other. Thus, this project will synergistically combine these two complementary methodologies, which are often employed in isolation.