CAREER: Modeling Ocean Particle Export Flux by Combining Particle Aggregation and Biogeochemical Models

海洋表层净生态系统生产的一个重要组成部分下沉到深处，在那里它可以被再矿化为二氧化碳或转移到海底。其中一些下沉颗粒是通过一系列过程形成的，这些过程产生了快速下沉的颗粒，这些颗粒有可能将碳运输到底栖生物而不需要再矿化。然而，目前很少有生物地球化学模型明确表示颗粒下沉的通量，而是依靠经验或半经验关系来垂直分布物质在水柱中。在这一综合研究和教育职业计划中，佐治亚大学的一名研究人员将重点研究海洋表面颗粒出口通量的数值模型的发展，该模型可以纳入区域和全球生物地球化学模型。这些模型的新颖之处在于，它们将集中于物理和生物过程（凝血和粪便颗粒生产），这些过程将单个的、缓慢下沉的颗粒转化为大的、快速下沉的颗粒。天真地将混凝模型纳入这些模型在计算上是禁止的，因此必须开发新的算法和参数化，以表示颗粒混凝的显著特征（例如，颗粒沉降速度）以及颗粒动力学，生态系统动力学和水柱物理特性（例如密度）之间的相互作用。这将使用日益复杂的物理和生物地球化学模型（如简单混合层模型和JGOFS区域试验台模型）来完成，每一阶段都在开发新的参数化和算法，并影响下一阶段。这项建议的教育部分与研究部分相结合，旨在利用真实世界的海洋学数据集，提高各级定量解决问题的能力。高中和中学教师将参加讲习班，在这些讲习班中，他们将为学生编写教材，涉及从公开的海洋学数据集进行定量分析。PI将进一步开发本科和研究生水平的课程，包括从大规模数据集构建和分析模型。这项工作将对生物地球化学循环和全球气候变化的研究人员以及政策制定者和公众产生相当大的兴趣，因为它提高了我们对海洋对地球气候影响做出更准确预测的能力。更广泛的影响还包括教师和学生更多地接触模型的开发和分析，以及它们在理解和解决现实世界海洋学问题中的应用。

OCE-0645485An important component of net ecosystem production in the surface ocean sinks to depth where it can be remineralized to carbon dioxide or transit to the bottom. Some of these sinking particles are formed via a number of processes that create rapidly sinking particles that have the potential to transport carbon to the benthos without remineralization. However, currently, very few biogeochemical models explicitly represent the flux of sinking of particles, relying instead on empirical or semi-empirical relationships to distribute material vertically in the water column.In this integrated research and education CAREER proposal, a researcher from the University of Georgia will focus on the development of numerical models of particle export flux from the surface ocean that can be incorporated into regional and global biogeochemical models. The novel aspect of these models is that they will concentrate on the physical and biological processes (coagulation and fecal pellet production) that transform individual, slowly sinking particles into large, rapidly sinking ones. Naively incorporating coagulation models into these models is computationally prohibitive, so new algorithms and parameterizations will have to be developed that represent the salient features of particle coagulation (e.g., particle settling velocities) and the interaction between particle dynamics, ecosystem dynamics and the physical properties of the water column (such as density). This will be accomplished using physical and biogeochemical models of increasing complexity (such as simple mixed layer models and the JGOFS Regional Test Bed Models), with new parameterizations and algorithms being developed at each stage and influencing the next one.The educational component of this proposal is integrated with the research component and aims at enhancing quantitative problem solving skills at all levels using real world, oceanographic data sets. High-school and middle-school teachers will be involved in workshops in which they will develop teaching materials for students involving quantitative analysis from publicly available oceanographic data sets. The PI will further develop undergraduate and graduate level courses that will include the construction and analysis of models from large-scale data sets. The work will be of considerable interest to researchers in biogeochemical cycling and global climate change as well as policy makers and the general public by increasing our ability to make more accurate predictions of the effect the ocean has on the planet's climate. The broader impacts also include increased exposure of teachers and students to the development and analysis of models and their use in understanding and solving real-world oceanographic problems.