Collaborative Research: Role of mixed layer eddies on phytoplankton productivity in seasonally variable regimes

这项研究有助于了解海洋的生物高度相关的区域，亚极地北大西洋，作为一个持久的大气碳汇。它评估了全球碳循环模型中没有的次中尺度过程的生物重要性。混合层涡旋，沿着由海气通量引起的湍流，调节浮游植物生产力的光和营养。 本研究探讨了混合层涡旋对副极地环流中浮游植物生产力的作用，在三个不同的阶段的年度循环-冬季，春季和夏季。通过模拟混合层涡旋与中尺度涡旋的相互作用，研究将提供关于它们的耦合如何影响密度跃层和混合层之间的垂直交换的见解。该项目将支持马萨诸塞州大学达特茅斯的一名博士后科学家和一名博士。在马萨诸塞州理工学院/伍兹霍尔海洋研究所联合项目学习四年。调查人员将通过新贝德福德海港海洋探索中心的海洋学院，利用数值和桌面实验演示海洋动力学，为包括教师培训和海洋扫盲讲习班在内的外联工作做出贡献。这项研究将是第一个包括垂直和横向过程（即湍流混合和1 - 10公里尺度的混合层涡旋）的研究，以了解上层海洋对短时间尺度（小时-天）上随时间变化的海气通量的反应。通过研究深冬混合层的分层机制，研究人员将评估在光照不足限制光合作用的时期（冬季和早春），漩涡和海气通量对浮游植物初级生产力的影响。他们将通过研究次表层中尺度涡旋与受间歇性海气通量影响的表层次中尺度场之间的耦合，研究强表层层化期间（夏季）平流垂直营养物的供应。这些过程的研究将有助于解决以下重要问题的浮游植物生产力在副极地海洋：（一）如何是一个种子浮游植物种群在冬季持续？(ii)春季层化的机制，无论是涡旋还是热效应，与整个季节的净初级生产力有关吗？(iii)在夏季强烈层化期间，营养物质是如何供应到表层的？这项调查将扩大目前的理解混合层涡旋，这是基于理想化的混合层设置的研究，通过考虑它们的相互作用与中尺度涡旋的密度跃层下面，并与表面湍流响应时间波动的海气通量。

This study contributes to the understanding of a biologically highly relevant region of the ocean, the subpolar North Atlantic, which acts as a persistent sink for atmospheric carbon. It assesses the biological importance of submesoscale processes, which are not represented in global carbon cycle models. Mixed layer eddies, along with the turbulence induced by air-sea fluxes, modulate both light and nutrients for phytoplankton productivity. This study explores the role of mixed layer eddies on phytoplankton productivity in the subpolar gyres during three distinct phases of the annual cycle - winter, spring, and summer. By modeling the interaction of mixed layer eddies with mesoscale eddies, the study will provide insight on how their coupling affects vertical exchange between the pycnocline and the mixed layer. The project will support a postdoctoral scientist at University of Massachusetts Dartmouth and a Ph.D. student in the Massachusetts Institute of Technology/Woods Hole Oceanographic Institution Joint Program for four years. The investigators will contribute to outreach efforts including teacher training, and ocean literacy workshops through the Ocean Academy at the Ocean Explorium at New Bedford Seaport by demonstrating ocean dynamics using numerical and tabletop experiments. This study will be amongst the first to include vertical and lateral processes (namely turbulent mixing and 1-10 km scale mixed layer eddies) in understanding the upper ocean's response to temporally varying air-sea fluxes on short time scales (hours-days). By studying the mechanisms generating stratification of deep winter mixed layers, the researchers will assess the effect of eddies and air-sea fluxes on phytoplankton primary productivity during times when a scarcity of light limits photosynthesis (in winter and early spring). By studying the coupling between subsurface mesoscale eddies and the surface submesoscale field subject to intermittent air-sea fluxes, they will examine the advective vertical nutrient supply during periods of strong surface stratification (summer). These process studies will help to address the following important questions about phytoplankton productivity in the subpolar oceans: (i) How is a seed phytoplankton population sustained over the winter? (ii) Is the mechanism for spring stratification, be it eddies or thermal effects, relevant to the net primary productivity over the season? (iii) How are nutrients supplied to the surface layer during times of strong stratification in the summer? This investigation will extend current understanding of mixed layer eddies, which is based on studies in idealized mixed layer settings, by considering their interaction with mesoscale eddies in the pycnocline beneath, and with surface turbulence in response to temporally fluctuating air-sea fluxes.