Collaborative Research: Biogeochemical Modeling of Carbon Partitioning in the Pacific: the Role of Si and Fe in Regulating Production by Siliceous and Calcifying Phytoplankton

物理和生物相互作用在大气、海洋上层、深海和沉积物之间的碳分配中发挥着复杂的作用。目前，跨学科模型提供了最好的手段来测试假设，碳分配是如何在不同的海洋区域的时间尺度上几年到几个世纪的调节。一个新的跨学科模型将整合几个领域的进展，以测试两个相关的假设：1）开关之间的社区和生产力优势硅藻和其他浮游植物群体（如非？硅质微型浮游生物和钙化浮游植物）显着影响碳的分配，在空间和时间上变化，并通过Si和Fe的组合进行调节的组合; 2）在南大洋的Si捕获的变化影响Si（OH）4浓度的“模式”沃茨，饲料赤道上升流，和Si和C的吸收赤道浮游植物改变空气？一个由生物和化学海洋学家和模型制作者组成的跨学科科学小组将通过四种方法解决这些问题。 首先，将钙化浮游植物组分添加到现有模型中，并用于合并水柱产生和CaCO 3溶解。 其次，模型实验将设计和执行，以探讨硅质（硅藻）和非？硅质（皮科和钙化）浮游生物。 第三，改进了为赤道太平洋开发的生物块体地球化学模式，将在空间上扩大到包括南大洋，并用于对连接高纬度“模式”水域与赤道上升流源沃茨的过程进行一系列模拟实验。 最后，铁？将对模型中浮游植物组成部分的敏感生长参数进行操作，以测试赤道太平洋和南大洋生态系统对铁富集的反应。这些目标是为探索海洋生物地球化学过程对气候变化的反应而发展耦合物理生物地球化学模式的重要一步。

Physical and biological interactions play a complex role in the partitioning of carbon between the atmosphere, upper ocean, deep ocean and sediments. At present, interdisciplinary models offer the best means to test hypotheses about how carbon partitioning is regulated in various oceanic regions on time scales of years to centuries. A new interdisciplinary model will integrate advances in several areas to test two related hypotheses: 1) that switches in community and productivity dominance between diatoms and other phytoplankton groups (e.g. non?siliceous picoplankton and calcifying phytoplankton) significantly affect carbon partitioning, vary spatially and temporally and are regulated by a combination of Si and Fe in combination; 2) that changes in Si trapping in the Southern Ocean affect Si(OH)4 concentrations in the "mode" waters that feed equatorial upwelling, and that Si and C uptake by equatorial phytoplankton alters air?sea exchange of carbon dioxide at the equator.An interdisciplinary science team of biological and chemical oceanographers and modelers will address these issues via four approaches. First, a calcifying phytoplankton component will be added to an existing model and used to incorporate water column production and dissolution of CaC03. Second, model experiments will be designed and executed to explore the regulation of switching between siliceous (diatoms) and non?siliceous (pico and calcifying) plankton. Third, an improved blogeochemical model developed for the equatorial Pacific will be spatially expanded to include the Southern Ocean, and used to conduct a series of simulation experiments on the processes that link high latitude "mode" water regions with the source waters for equatorial upwelling. Finally, iron?sensitive growth parameters of the phytoplankton components of the model will be manipulated to test the ecosystem response to iron enrichment in both the equatorial Pacific Ocean and the Southern Ocean. These objectives represent a significant step in the development of coupled physical biogeochemical models for exploring the response of marine biogeochemical processes to climate change.