Collaborative Research: Forcing and the North Atlantic Spring Bloom

这项建议的目标是确定是否容易观察到的物理过程控制浮游植物水华在北大西洋的启动。 该假说认为，水华是由冬末/早春热损失和风减弱时混合减少引发的。 对于一个简单的植物生长素-营养盐系统与广泛的生物参数，水华发展在现实的对流湍流模式在上层海洋时，表面冷却到加热在春天。 这项工作假设，湍流的变化很容易从可观察到的属性中预测出来，并且足够强大，可以在任何允许它们的生物模型中引发水华。 与以前的解释，这是非常敏感的生物相互作用的细节，这是知之甚少，难以量化，这种大气强迫假说是可以测试的远程和原位数据，可以约束物理参数比生物更好。 这个项目将扩展我们现有的标准，考虑到风强迫，蒸发和降水的水华开始。 将评估该标准适用的生物模型和参数的范围。 该理论将使用数值模拟，新的滑翔机数据（收集），一个既定的英国时间序列站，和可用的卫星数据进行测试。 拟议的项目是一个及时、独特和具有成本效益的机会，可以解决海洋学中持续时间最长、研究最深入的问题之一：春季水华，一种每年一度的种群爆炸，主导着全球大部分海洋浮游植物丰度的季节性周期，证实了海洋生物学和物理学之间的相互作用。 持续活跃的争论控制水华的开始主要是由于缺乏可检验的假设和适当的原位数据。 经过60年的研究，这一主题的生物海洋学社区，理论和技术现在已经足够先进的地步，我们可以解决物理过程和水华之间的相互作用的根本悬而未决的问题。 通过耦合现代湍流和生物模型，由观测到的大气强迫驱动它们，并将结果与观测结果进行比较，我们将确定通过了解强迫可以预测水华的各个方面的程度，并对这一现象有更深入的了解。北大西洋的浮游植物水华对于推动海洋碳吸收和支持生态系统非常重要，包括北美和欧洲的渔业。 因此，该提案针对的是短期（渔业）和长期（气候变化）与社会相关的主题。该提案有一个强大的教育组成部分，通过培训研究生和博士后在跨学科研究的主题越来越重要，我们对气候系统的理解。 与英国同事合作收集相关数据是另一个重要方面。

The goal of this proposal is to determine whether easily observed physical processes control phytoplankton bloom initiation in the North Atlantic. The hypothesis is that blooms are triggered by a reduction in mixing in late winter/early spring when heat loss and winds weaken. For a simple phytoplankton-nutrient system with a wide range of biological parameters, blooms develop in realistic models of convective turbulence in the upper ocean when the surface cooling changes into heating in spring. This work hypothesizes that the change in turbulence is readily predicted from observable properties and is strong enough to spark a bloom in any biological model that admits them. Unlike previous explanations which are very sensitive to details of the biological interactions which are both poorly understood and difficult to quantify, this atmospheric forcing hypothesis is testable with remote and in-situ data which can constrain physical parameters much better than biological ones. This project will extend our existing criterion for bloom initiation to account for wind forcing, evaporation and precipitation. The range of biological models and parameters for which the criterion works well will be assessed. The theory will be tested using numerical simulations, new glider data (to be collected), an established UK time-series station, and available satellite data. The proposed project is a timely, unique and cost-effective opportunity to address one of the longest-running and most intensively studied problems in oceanography.The spring bloom, an annual population explosion that dominates the seasonal cycle of phytoplankton abundance in much of the global ocean, exemplifies the interplay between ocean biology and physics. The continuing lively debate on the processes controlling bloom initiation is driven largely by the paucity of testable hypothesis and suitable in-situ data. After 60 years of research into this topic by the biological oceanography community, theory and technology has now advanced sufficiently to the point where we can resolve fundamental outstanding questions on the interactions between physical processes and bloom timing. By coupling modern turbulence and biological models, driving them by observed atmospheric forcings, and comparing results with observations, we will determine the degree to which aspects of the bloom can be predicted simply by knowing the forcing and gain a deeper understanding of the phenomenon.Phytoplankton blooms in the North Atlantic are important for driving ocean carbon uptake and supporting ecosystems, including the fisheries of the North Americas and Europe. Hence this proposal targets topics of relevance for society both in the short term (fisheries) and long term (climate change). The proposal has a strong educational component through the training of a graduate student and a postdoc in interdisciplinary research on topics of growing importance for our understanding of the climate system. The international collaboration with UK colleagues to collect relevant data is another important aspect.