CAREER: Lakes on a Changing Landscape: A Disturbance Phenology for Phytoplankton Communities and Ecosystem Function

淡水湖中的藻类是环境变化的哨兵，因为它们对干扰反应迅速。当藻类对外界干扰作出反应时，它们会通过生长波动、碳和营养物质的处理以及生物相互作用来改变周围环境。这使得藻类成为湖泊营养循环和气体交换等生态系统功能的重要媒介。过去，湖泊生态系统过程的规律性使预测藻类群落组成和影响湖泊生态系统功能的特征成为可能。然而，湖泊生态系统正在迅速变化，以响应多种相互作用的环境变化干扰，使以前可预测的季节性过程（如冰盖、蒸发和径流）变得越来越不确定和混乱。该项目将确定在短期和长期的时间尺度上，在扰动强度梯度上赋予持久性的藻类特征。该项目旨在了解藻类群落是如何形成并影响生态系统功能的，而不是作为对预期稳定条件的破坏，而是作为一个波动的动态过程。作为CAREER提案的一部分，该研究将被纳入本科课程，并将使用协作团队科学方法培训本科生、研究生和博士后研究员。通过与湖泊管理者和专业讲习班建立伙伴关系，研究结果将与利益攸关方沟通，并转化为管理行动。该奖项旨在描述浮游植物群落聚集的干扰物候框架，该框架可跨空间和时间扩展，以预测湖泊生态系统功能的反馈和阈值变化。首先，该项目将试图了解近岸底栖和开放水域中上层垂直带藻类对压力源响应的异质性，以更好地预测生态系统对随机事件的响应。在整个湖区，浮游植物群落的同步波动预计会放大和破坏生态系统功能，通过湖泊代谢、二氧化碳和甲烷通量来测量。其次，该项目将调查浮游植物在时间尺度上赋予持久性的特征，并将测试在短期随机干扰（如休眠或替代代谢策略）下赋予持久性的特征将在几十年的时间尺度上被招募到群落的假设。假设将在实验室微观环境、室外中生态环境中进行测试，并使用现代和古湖泊学方法在五个湖泊的营养梯度中进行测试。实验中生态系统、高频传感器阵列和显微镜设备将被整合到本科湖沼学、生理学和生态系统生态学课程中，旨在培养学生的团队科学、实验设计和生态理论。该项目由环境生物学部的人口与社区生态集群和生态系统科学集群以及促进竞争研究的既定计划（EPSCoR）共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Algae in freshwater lakes are sentinels of environmental change because they respond rapidly to disturbances. As they respond to disturbance, algae alter their surrounding environment through fluctuations in their growth, the processing of carbon and nutrients, and biotic interactions. This makes algae important mediators of lake ecosystem functions such as nutrient cycles and gas exchange. In the past, the regular seasonality of lake ecosystem processes made it possible to predict the composition of algal communities and the traits that influence lake ecosystem function. Lake ecosystems, however, are changing rapidly in response to multiple interacting environmental change disturbances, making previously predictable seasonal processes such as ice cover, evaporation, and run-off increasingly uncertain and chaotic. This project will identify algal traits that confer persistence across a gradient of disturbance intensity over short and long timescales. This project seeks to understand how algal communities form and influence ecosystem function, not as a disruption to expected stable conditions, but as a fluctuating, dynamic process. As part of this CAREER proposal, the research will be integrated into undergraduate curriculum and will train undergraduates, a graduate student, and a postdoctoral researcher using collaborative team science approaches. Through a partnership with lake managers and professional workshops, findings will be communicated with stakeholders and translated into management action. This CAREER award aims to describe a disturbance phenology framework for phytoplankton community assembly that is scalable across space and time in order to predict feedbacks and threshold shifts for lake ecosystem function. First, the project will seek to understand the heterogeneity of algal responses to stressors across nearshore benthic and open water pelagic vertical zones to better predict ecosystem scale response to stochastic events. Across lake zones, synchronous fluctuations of phytoplankton communities are expected to amplify and destabilize ecosystem function, measured as lake metabolism, carbon dioxide, and methane flux. Second, the project will investigate phytoplankton traits that confer persistence across time scales, and will test the hypothesis that traits which confer persistence in response to short term, stochastic disturbance such as dormancy or alternative metabolic strategies will be recruited to communities over multi-decadal time scales. Hypotheses will be tested across scales in laboratory microcosms, outdoor mesocosms, and using modern and paleolimnological approaches across a trophic gradient in five lakes. Experimental mesocosms, high-frequency sensor arrays, and microscopy facilities will be integrated into undergraduate limnology, phycology, and ecosystem ecology curriculum aimed at training students in team science, experimental design, and ecological theory. This project is jointly funded by the Population and Community Ecology Cluster and Ecosystem Science Clusters in the Division of Environmental Biology and the Established Program to Stimulate Competitive Research (EPSCoR).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.