Collaborative Research: Regulation of Phytoplankton Dynamics in Mid-Atlantic Estuaries Subject to Climatic Perturbations.

旱涝循环、热带风暴和飓风引起的气候扰动在中大西洋河口日益重要，导致浮游生物系统的生态系统尺度响应，具有重要的营养意义。最近的观测支持了一个新兴的范式，即气候在这些生态系统中主导着营养富集，解释了浮游植物的植物组成、生物量（chl-a）和初级产量（PP）的季节和年际变化。该项目将通过量化对气候扰动的响应，在美国两个最大的河口，切萨皮克湾（CB）和阿尔伯马尔-帕姆利科海湾-纽斯河河口（APS-NRE）评估这一范式。该项目将：(1)解决由气候强迫驱动的高变异性浮游生物生物量/产量的长期趋势，例如导致显著偏离常态的旱涝周期；(2)量化偶发性风和降水事件的作用，如与锋面通道、热带风暴和飓风相关的风和降水事件，这些事件会引起传统方法无法解决的生物量/产量的相应峰值。实地项目将通过收集船载、飞机遥感和卫星（SeaWiFS、MODIS-A）数据，分析CB和APS-NRE的广泛监测数据来发展背景，并量化气候扰动对浮游植物动力学偏离长期平均值的影响，重点关注浮游植物动力学的事件尺度强迫。快速响应采样将与基于区域海洋模拟系统（ROMS）的耦合水动力生物地球化学模型的数值模拟相结合。这种观察和建模的结合将用于探索机械联系和测试从现场数据中获得的经验关系。知识价值。旱涝周期、热带风暴和飓风的发生日益严重和频繁，给土地边缘生态系统带来了巨大压力。近50年来，对这些生态系统的研究和监测一直集中在富营养化问题上。认识到气候扰动是浮游植物变异的根本原因，代表着对这一单一焦点的重大偏离。该项目将结合观测和建模，以显著扩展我们对气候如何调节河口浮游植物动态的认识。该项目利用CB和APS-NRE收集的数据校准和验证水动力生物地球化学模型的进展将导致迄今为止尚未实现的预测能力，使我们能够评估气候扰动调节河口浮游植物动态的范式。更广泛的影响：结合数据收集、分析和机制建模来解决气候扰动对河口浮游植物动态的影响，对科学家和资源管理者具有社会效益。应用程序除了基本？科学包括在设计有效的养分管理策略时考虑气候强迫。具体影响包括：(1)量化气候扰动对重要河口-海岸生态系统浮游过程的影响；(2)通过对气候变化条件下植物组成、chl-a和PP的预测，进一步扩展了基于经验的水质标准；(3)结合观测和机制模式来支持情景分析，使我们能够区分长期趋势和气候造成的变率。该项目将提供一门物理运输过程和浮游生物生产力的研究生课程，该课程将从本研究中受益，支持两名博士生，并在NSF REU和HPL-UMCES和IMS-UNC的少数民族外展项目中培训本科生。主要产品将是同行评审的出版物和科学会议上的报告。这三家pi维护活跃的网站，将用于发布结果和数据。

Climatic perturbations by drought-flood cycles, tropical storms, and hurricanes are increasingly important in Mid-Atlantic estuaries, leading to ecosystem-scale responses of the plankton system with significant trophic implications. Recent observations support an emerging paradigm that climate dominates nutrient enrichment in these ecosystems, explaining seasonal and interannual variability of phytoplankton floral composition, biomass (chl-a), and primary production (PP). This project will evaluate this paradigm in the two largest estuaries in the United States, Chesapeake Bay (CB) and Albemarle-Pamlico Sound-Neuse River Estuary (APS-NRE) by quantifying responses to climatic perturbations. This project will: (1) resolve long-term trends of plankton biomass/production from high variability driven by climatic forcing, such as drought-flood cycles that generate significant departures from the norm; (2) quantify the role of episodic wind and precipitation events, such as those associated with frontal passages, tropical storms, and hurricanes, that evoke consequential spikes of biomass/production outside the resolution of traditional methods. The field program will focus on event-scale forcing of phytoplankton dynamics by collecting shipboard, aircraft remote sensing, and satellite (SeaWiFS, MODIS-A) data, analyzing extensive monitoring data for CB and APS-NRE to develop context, and quantifying effects of climatic perturbations on phytoplankton dynamics as departures from long-term averages. The rapid-response sampling will be paired with numerical simulations using coupled hydrodynamic biogeochemical models based on the Regional Ocean Modeling System (ROMS). This combination of observations and modeling will be used to explore mechanistic links and test empirical relationships obtained from field data.Intellectual Merit. Drought-flood cycles, tropical storms, and hurricanes are occurring at increasing severity and frequency, exerting significant pressures on land margin ecosystems. Research and monitoring in these ecosystems has focused singularly on eutrophication for nearly five decades. Recognition of climatic perturbations as the underlying cause of phytoplankton variability represents a significant departure from this singular focus. This project will combine observations and modeling to significantly extend our knowledge of how climate regulates phytoplankton dynamics in estuaries. Progress in calibrating and validating hydrodynamic biogeochemical models with data collected in CB and APS-NRE by this project will lead to predictive capabilities thus far unattained, allowing us to evaluate the paradigm that climatic perturbations regulate phytoplankton dynamics in estuaries.Broader Impacts: Addressing the effects of climatic perturbations on phytoplankton dynamics in estuaries with a combination of data collection, analysis, and mechanistic modeling has societal benefits for scientists and resource managers. Applications in addition to ?basic? science include the consideration of climatic forcing in designing effective nutrient management strategies. Specific impacts include: (1) quantifying the effects of climatic perturbations on planktonic processes for important estuarine-coastal ecosystems; (2) extending empirically-based water quality criteria forward by enabling predictions of floral composition, chl-a, and PP in changing climate conditions; (3) combining observations and mechanistic models to support scenario analysis, allowing us to distinguish long-term trends from variability imposed by climate. This project will offer a graduate course in physical transport processes and plankton productivity that will benefit from this research, support two Ph.D. students, and train undergraduates in NSF REU and minority outreach programs at HPL-UMCES and IMS-UNC. The main products will be peer-reviewed publications and presentations at scientific meetings. The three PIs maintain active web sites that will be used to distribute results and data.