Collaborative Research: Impacts of Eddies and Mixing on Plankton Community Structure and Biogeochemical Cycling in the Sargasso Sea

合作研究：涡流和混合对马尾藻海浮游生物群落结构和生物地球化学循环的影响

• 批准号: 0241023
• 负责人: Paul Falkowski
• 金额: --
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2007-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0241023&HistoricalAwards=false
• 关键词: Collaborative; Research; Impacts; Eddies; Mixing

ABSTRACTOCE-0241310 / OCE-0241399 / OCE-0241023 / OCE-0241340 / OCE-0241011The currents, fronts and eddies that comprise the oceanic mesoscale, sometimes referred to as the "internal weather of the sea," are highly energetic and ubiquitous features of ocean circulation. Dynamical consequences of these phenomena include perturbation of the chemical and biological environment that can dramatically impact biogeochemical cycling in the ocean. The processes that regulate this response are extraordinarily complex, challenging us to understand how the physical, biological and chemical processes are functionally related.Recent evidence suggests that mesoscale eddies are an important nutrient transport mechanism in the oligotrophic waters of the main subtropical gyres. Numerical simulations and satellite-based statistical estimates indicate that the magnitude of the eddy-driven nutrient flux could be sufficient to balance geochemical estimates of new production, which far exceed that which can be sustained by traditional mechanisms of nutrient supply. Relatively few direct observations of this process are available, owing to the spatial and temporal intermittency of the events that drive it. Available data demonstrate that isopycnal displacements associated with certain types of eddies can transport nutrients into the euphotic zone, resulting in the accumulation of chlorophyll in the overlying waters. However, the nature of the biological response and its impact on coupled biogeochemical cycles and export has yet to be elucidated. Furthermore, the relationship between eddy-induced upwelling and diapycnal mixing in and below the mixed layer remains obscure; the strength of this interaction determines the degree to which the eddy-driven effects are irreversible and thereby effect a net biogeochemical flux.In this project, a team of oceanographic researchers will document phytoplankton physiological response, changes in community structure, export and the biogeochemical ramifications of eddy-induced upwelling and mixing in the Sargasso Sea. Target features will be identified prior to field deployment via remote sensing. High-resolution surveys will be undertaken with an undulating towed instrument package that includes a Fast Repetition Rate Fluorometer. This suite of instruments will facilitate simultaneous assessment of photosynthetic parameters and the species assemblage of phytoplankton and zooplankton. These measurements will be accompanied by discrete water sampling of biogeochemical properties in sets of stations along cross sections of the chosen features. Export will be measured at selected locations within the mesoscale structure. Rates of mixing between the surface mixed layer and waters at the base of the euphotic zone will be inferred from the Helium flux gauge and measured directly with a sulfur hexafluoride tracer release. Taken together, these observations will be sufficient to test the hypothesis that eddy-induced upwelling increases photosynthetic rates, changes community structure and increases export from the euphotic zone, thereby playing an important role in biogeochemical cycling of the subtropical oceans.The research will be carried out in a collaborative effort among ten principal investigators from the Woods Hole Oceanographic Institution, the Bermuda Biological Station for Research, Rutgers University, University of California, Santa Barbara, and the University of Miami. The work plan consists of two years of field observations followed by a final year of synthesis.

Abstractoce-0241310 / OCE-0241399 / OCE-0241023 / OCE-0241340 / OCE-02410111111的电流，前部和涡流包括海洋中尺度的，有时被称为“海上天气”，“高度充满活力”和Ubiquipit的特征，是“海洋的内部天气”。 这些现象的动态后果包括化学和生物学环境的扰动，这些化学和生物环境可能会极大地影响海洋生物地球化学循环。调节这种反应的过程非常复杂，挑战我们了解物理，生物学和化学过程在功能上是相关的。持续的证据表明，中尺度的涡流是主要亚热带Gyres的寡地营养水中的重要养分运输机制。数值模拟和基于卫星的统计估计表明，涡流驱动的养分通量的大小足以平衡新产量的地球化学估计，这远远超过了传统的营养供应机制可以维持的生产。由于驱动它的事件的空间和时间间歇性，因此对此过程的直接观察相对较少。可用的数据表明，与某些类型的涡流相关的等激素位移可以将养分传输到舒适的区域，从而导致叶绿素在上覆水中的积累。然而，生物反应的性质及其对耦合生物地球化学周期和出口的影响尚未阐明。此外，混合层内和下方的涡流诱导的上升和二比混合之间的关系仍然晦涩难懂。这种互动的强度决定了涡流驱动的效果是不可逆的，从而影响了净生物地球化学磁通。在该项目中，一组海洋学研究人员将记录植物浮游生物的生理反应，社区结构的变化，出口，出口和生物地球化学诱导的sARWELLing和Sargasso中的生物地球化学后果。目标功能将在通过遥控感测现场部署之前确定。 高分辨率调查将使用起伏的拖曳仪器包进行，其中包括快速重复率荧光计。这套工具将有助于同时评估光合参数以及浮游植物和浮游动物的物种组合。这些测量结果将伴随着所选特征的横截面沿横截面的一组生物地球化学性质的离散水采样。导出将在中尺度结构内的选定位置进行测量。将从氦气量表上推断出表面混合层和水底的水之间的混合速率，并用硫六氟化物示踪剂释放直接测量。综上所述，这些观察结果将足以检验以下假说：涡流引起的上升速度提高了光合率，改变了社区结构，增加了从舒适区的出口，从而在亚热带海洋的生物地球化学循环中发挥了重要作用。该研究将在研究中进行研究，以对林木的协作进行研究，从而在林中进行协作，以实现林木的协作，居住在林中，居住在林中，居住在林中，居住在林中，居住在林木中，居住在林木中，居住在林中，居住在林中，居住在林中，居住在林木中，居住在林木中。罗格斯大学，加利福尼亚大学，圣塔芭芭拉大学和迈阿密大学。该工作计划包括两年的现场观察，然后是合成的最后一年。