Dimensions: Collaborative Research: Genetic, functional and phylogenetic diversity determines marine phytoplankton community responses to changing temperature and nutrients

光合作用的海洋微生物，即浮游植物，贡献了全球初级生产的一半，构成了大多数水生食物网的基础，是全球生物地球化学循环的主要参与者。了解它们的群落组成很重要，因为它影响更高的营养水平、能量和元素的循环，并且对全球环境变化很敏感。该项目将研究浮游植物群落如何应对水生系统中两个主要的全球变化压力源：变暖和养分可用性的变化。研究人员将在两个具有长期环境监测历史的海洋系统中工作，一个是罗德岛的温带纳拉甘西特湾河口，另一个是百慕大附近的亚热带北大西洋海域。他们将对多种浮游植物进行实地取样和实验室试验，以评估它们在高和低营养浓度下对不同温度的反应的多样性。如果物种内部反应的多样性很高，那么该物种可能有更好的机会适应不断上升的温度并在未来持续存在。一些物种可能已经能够在高温下生长；因此，随着海洋变暖，它们可能会变得更加丰富。研究人员将把这些响应信息纳入数学模型，以预测浮游植物组合在未来气候情景下将如何重组。研究生和博士后将接受各种科学方法和技术的培训，如船上采样、实验室实验、基因组分析和数学建模。该项目的成果将被纳入K-12课程的教学，包括为洛杉矶少数族裔开设的高级环境科学课程，为密歇根州农村学校开设的数据练习，并通过设在罗德岛的环境新闻研究所向公众传播。预测生态群落如何应对不断变化的环境需要了解物种内部和物种间的遗传、系统发育和功能多样性。该项目将研究多种物种内部和物种间热特性的系统发育、遗传和功能多样性的相互作用如何决定海洋浮游植物群落对温度上升和营养状况变化的反应。一个物种内部高度的遗传和功能多样性可能允许该物种进化适应变暖。如果物种间的系统发育和功能多样性较高，则可能发生物种分选和生态群落重组。不同的海洋地点可能在物种内部和物种间具有不同的遗传和功能多样性平衡，因此，对气候变化的进化和生态反应的贡献也不同。这项研究将在大西洋的两个长期时间序列站点进行，纳拉甘西特湾长期浮游生物时间序列和百慕大大西洋时间序列（BATS）站。目的是评估不同季节两个地点的代表性物种在不同营养浓度下热响应的种内和种间遗传和功能多样性，并利用这些信息将生态进化模型参数化到生物地球化学海洋模型中，以预测在现实营养条件下浮游植物群落对预测温度上升的反应。模式预测将以实地数据为依据，并以实地数据进行检验，包括两个站点和社区温度操纵实验中可用的长期数据系列。本项目将为许多生态和生物地球化学上重要的浮游植物物种提供现有种内遗传和功能热多样性的新信息，在进化实验中估计新的遗传和功能多样性的产生，并开发和参数化与海洋生物地球化学模型相结合的新型生态进化模型，以预测未来浮游植物群落结构。该项目还将描述两个主要的全球变化压力源，即变暖和营养物浓度变化的相互作用，因为它们在功能、遗传和系统发育水平上影响浮游植物的多样性。此外，该项目将开发新的建模方法，该方法将广泛适用于了解其他类型的复杂生态群落如何适应快速变暖的世界。

Photosynthetic marine microbes, phytoplankton, contribute half of global primary production, form the base of most aquatic food webs and are major players in global biogeochemical cycles. Understanding their community composition is important because it affects higher trophic levels, the cycling of energy and elements and is sensitive to global environmental change. This project will investigate how phytoplankton communities respond to two major global change stressors in aquatic systems: warming and changes in nutrient availability. The researchers will work in two marine systems with a long history of environmental monitoring, the temperate Narragansett Bay estuary in Rhode Island and a subtropical North Atlantic site near Bermuda. They will use field sampling and laboratory experiments with multiple species and varieties of phytoplankton to assess the diversity in their responses to different temperatures under high and low nutrient concentrations. If the diversity of responses is high within species, then that species may have a better chance to adapt to rising temperatures and persist in the future. Some species may already be able to grow at high temperatures; consequently, they may become more abundant as the ocean warms. The researchers will incorporate this response information in mathematical models to predict how phytoplankton assemblages would reorganize under future climate scenarios. Graduate students and postdoctoral associates will be trained in diverse scientific approaches and techniques such as shipboard sampling, laboratory experiments, genomic analyses and mathematical modeling. The results of the project will be incorporated into K-12 teaching, including an advanced placement environmental science class for underrepresented minorities in Los Angeles, data exercises for rural schools in Michigan and disseminated to the public through an environmental journalism institute based in Rhode Island.Predicting how ecological communities will respond to a changing environment requires knowledge of genetic, phylogenetic and functional diversity within and across species. This project will investigate how the interaction of phylogenetic, genetic and functional diversity in thermal traits within and across a broad range of species determines the responses of marine phytoplankton communities to rising temperature and changing nutrient regimes. High genetic and functional diversity within a species may allow evolutionary adaptation of that species to warming. If the phylogenetic and functional diversity is higher across species, species sorting and ecological community reorganization is likely. Different marine sites may have a different balance of genetic and functional diversity within and across species and, thus, different contribution of evolutionary and ecological responses to changing climate. The research will be conducted at two long-term time series sites in the Atlantic Ocean, the Narragansett Bay Long-Term Plankton Time Series and the Bermuda Atlantic Time Series (BATS) station. The goal is to assess intra- and inter-specific genetic and functional diversity in thermal responses at contrasting nutrient concentrations for a representative range of species in communities at the two sites in different seasons, and use this information to parameterize eco-evolutionary models embedded into biogeochemical ocean models to predict responses of phytoplankton communities to projected rising temperatures under realistic nutrient conditions. Model predictions will be informed by and tested with field data, including the long-term data series available for both sites and in community temperature manipulation experiments. This project will provide novel information on existing intraspecific genetic and functional thermal diversity for many ecologically and biogeochemically important phytoplankton species, estimate generation of new genetic and functional diversity in evolution experiments, and develop and parameterize novel eco-evolutionary models interfaced with ocean biogeochemical models to predict future phytoplankton community structure. The project will also characterize the interaction of two major global change stressors, warming and changing nutrient concentrations, as they affect phytoplankton diversity at functional, genetic, and phylogenetic levels. In addition, the project will develop novel modeling methodology that will be broadly applicable to understanding how other types of complex ecological communities may adapt to a rapidly warming world.