A power law model of dynamic marine phytoplankton stoichiometry

近一个世纪前，阿尔弗雷德·雷德菲尔德观察到，海洋浮游植物中碳、氮和磷元素的比例在整个海洋中几乎相同。这一观测结果后来被称为“雷德菲尔德比”，是生物和化学海洋学的中心概念。雷德菲尔德比率提供了一种方便和有用的方法，可以将营养物质(氮和磷)的吸收与碳联系起来，并探索海洋碳循环的各个方面。然而，最近的研究强调了碳、氮、磷(C：N：P)比率可能会以多种方式变化，这表明应该重新考虑它们不变的简单假设。该项目的总体目标是开发一种方法，将不同的C：N：P比率纳入海洋模型，使研究人员能够探索这些变化对碳循环的影响。拟议的工作将直接支持研究生研究人员，并包括与当地学校的STEM外联。该项目将开发灵活的浮游植物化学计量学的幂定律模型，这种方法能够捕获元素比率作为多个环境驱动因素的函数的非线性行为。幂定律模型的中心特征是一个系数，它对浮游植物生物化学(即浮游植物的动态平衡)和海洋生物地球化学(即全球碳出口生产对环境变化的缓冲能力)产生了有用的见解。此外，幂定律模型在数学上是稳健的，因此很容易移植到全球海洋模型中。幂定律模型的这些属性有望促进全球海洋模型对动态化学计量学的广泛研究。研究人员还将用他们的新化学计量模型启用两个全球海洋模型，并量化持续全球变暖和晚更新世冰期条件下的化学计量-生物地球化学循环-气候反馈。因此，这项研究将通过开发一种新的方法来表示海洋模型中的化学计量多样性并量化这种多样性在不同气候条件下的全球影响，从而对化学海洋学做出重大贡献。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Almost a century ago, Alfred Redfield observed that the ratios of the elements carbon, nitrogen, and phosphorus in ocean phytoplankton were nearly the same throughout the oceans. This observation came to be called the "Redfield ratio" and is a central idea in biological and chemical oceanography. The Redfield ratio provides a convenient and useful way of relating the uptake of nutrients (nitrogen and phosphorus) and carbon, and of exploring aspects of ocean carbon cycling. Recent work, however, has highlighted the many ways in which the carbon to nitrogen to phosphorus (C:N:P) ratios can vary, suggesting that the simple assumption that they are unchanging should be revisited. The overall goal of this project is to develop a way of incorporating varying C:N:P ratios into ocean models that will allow researchers to explore the impacts of these variations on carbon cycling. The proposed work will directly support graduate student researchers and include STEM outreach to local schools. This project will develop a power law model of flexible phytoplankton stoichiometry, an approach that is able to capture the nonlinear behavior of the elemental ratios as a function of multiple environmental drivers. The central feature of the power law model is a coefficient that yields useful insights about phytoplankton biochemistry (i.e., phytoplankton homeostasis) and ocean biogeochemistry (i.e., the buffer capacity of the global carbon export production to environmental changes). Furthermore, the power law model is mathematically robust and thus easily ported to global ocean models. These attributes of the power law model are expected to facilitate widespread studies of dynamic stoichiometry with global ocean models. The investigators will also enable two global ocean models with their new stoichiometry model and quantify the stoichiometry-biogeochemical cycles-climate feedbacks under ongoing global warming and late Pleistocene ice age conditions. This study will thus make a significant contribution to chemical oceanography by developing a new approach to representing stoichiometric diversity in ocean models and by quantifying the global impacts of that diversity under different climate conditions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.