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，浮游植物，贡献了全球初级生产量的一半，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，并对全球环境变化敏感。该项目将调查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来源：变暖和养分供应的变化。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，一个是罗德岛温带的纳拉甘西特湾河口，另一个是百慕大附近的北大西洋亚热带地区。他们将对多种浮游植物进行实地采样和实验室实验，以评估它们在营养物质浓度高和低的情况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气温上升并在未来持续下去。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。研究人员将把这种响应信息纳入数学模型，以预测未来气候情景下浮游植物群落将如何重组。研究生和博士后助理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，包括为洛杉矶未被充分代表的少数族裔开设环境科学高级班，为密歇根州的乡村学校进行数据练习，并通过罗德岛的一个环境新闻研究所向公众传播。预测生态社区将如何应对不断变化的环境需要了解物种内和物种之间的遗传、系统发育和功能多样性。该项目将调查广泛物种内部和跨物种的热特征的系统发育、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制度变化的反应。物种内高度的遗传和功能多样性可能会使该物种在进化上适应气候变暖。如果物种间的系统发育和功能多样性较高，则物种分类和生态群落重组是可能的。不同的海洋地点可能在物种内和物种之间具有不同的遗传和功能多样性平衡，因此，进化和生态反应对气候变化的贡献也不同。研究将在大西洋的两个长期时间序列站点--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)站进行。其目标是评估两个地点不同季节群落中典型物种在营养浓度不同时的种内和种间遗传和功能多样性，并利用这一信息将嵌入生物地球化学海洋模型的生态进化模型参数化，以预测浮游植物群落对现实营养条件下预计气温上升的反应。模型预测将由现场数据提供信息，并用现场数据进行测试，包括两个地点和社区温度操纵实验中可用的长期数据系列。该项目将为许多具有生态和生物地球化学意义的重要浮游植物物种现有的种内遗传和功能热多样性提供新的信息，在进化实验中估计新的遗传和功能多样性的产生，并开发与海洋生物地球化学模型相结合的新的生态进化模型并将其参数化，以预测未来的浮游植物群落结构。该项目还将描述两个主要的全球变化应激源--变暖和不断变化的营养物质浓度--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多样性。此外，该项目将开发新的建模方法，这种方法将广泛适用于理解其他类型的复杂生态群落如何适应迅速变暖的世界。

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.