CAREER: An integrated molecular and physiological approach to examining the dynamics of upwelled phytoplankton in current and changing oceans

上升流带是光合作用的热点，在空间和时间上都是非常动态的。微型浮游藻类被称为浮游植物，当营养丰富的深水涌入阳光充足的海洋表层时，会发生水华，提供营养，支持生产性的食物网，并将二氧化碳(CO2)从大气中吸收到深海。这些地区的光合作用微生物必须不断适应其化学和物理环境的变化。例如，地下种群在接近地表时会对光线的变化做出反应。当上升流向近海移动时，细胞下沉出照明区，建立种子种群，在下一次上升流事件之前保持不活跃。这个过程被称为上升式传送带循环(UCBC)。浮游植物如何应对这些环境条件的变化，以及它们可能如何影响它们的营养需求，目前尚不清楚。由于未来的海洋变化预计将改变海水化学，包括海洋酸化和铁可获得性的减少，一些浮游植物群体可能比其他群体更脆弱。伴随的教育活动提供学习经验，以加强对海洋微生物的了解和认识。在北卡罗来纳大学建立研究中心的目的是为科学家和学生进行环境基因组学研究提供基础设施和支持。正在开发一门以海洋浮游植物为重点的高级本科课程的实验室组成部分。面向更广泛社区的教育外展活动包括为中学生创建关于上升流区浮游植物的课程计划和虚拟研究邮轮体验，以及为当地一家博物馆举办动手实验室活动，重点关注海洋浮游植物及其在塑造我们的星球中所起的重要作用。该项目研究了浮游植物如何在分子和生理水平上对不同的UCBC阶段做出反应，在不同强度的上升流事件期间，哪些种子种群(即表层和地下)对浮游植物水华的贡献最大，浮游植物元素组成在整个UCBC阶段是如何改变的，以及未来预测的海洋条件将如何影响浮游植物对UCBC条件的反应。这个项目包括实验室和实地考察两部分。在实验室中，最近从上升流地区获得的浮游植物分离株暴露在模拟UCBC条件下，以检测基因表达、生长、光合作用特征和元素组成的变化。培养物同时受到当前和未来海洋条件的影响，包括铁的可获得性减少和二氧化碳增加。在实地，上升流区域的研究游轮研究自然浮游植物群落(表层和次表层)经历上升流和松弛的动力学，并在模拟上升流孵化实验中进行研究。在目前和未来的情况下，从分子、生理和元素的综合水平上了解浮游植物如何受到UCBC条件的影响，对于正确保护和管理这些至关重要的生态系统至关重要。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Upwelling zones are hotspots of photosynthesis that are very dynamic in space and time. Microsocopic algae, known as phytoplankton, bloom when deep, nutrient-rich waters are upwelled into sunlit surface layers of the ocean, providing nourishment that supports productive food webs and draws down carbon dioxide (CO2) from the atmosphere to the deep ocean. Photosynthetic microbes in these regions must constantly adapt to changes in their chemical and physical environments. For example, subsurface populations respond to changes in light as they approach the surface. When upwelled waters move offshore, cells sink out of the illuminated zone, establishing seed populations that remain inactive until the next upwelling event. This process is called the upwelling conveyor belt cycle (UCBC). How phytoplankton respond to these changes in environmental conditions and how they may influence their nutrient requirements remains unknown. With future ocean changes predicted to alter seawater chemistry, including ocean acidification and decreased iron availability, some phytoplankton groups may be more vulnerable than others. Accompanying educational activities provide learning experiences to enhance understanding and awareness of marine microbes. The development of a research hub at UNC aims to provide infrastructure and support for scientists and students conducting research on environmental genomics. A laboratory component for an upper-level undergraduate course focused on marine phytoplankton is being developed. Educational outreach activities to broader communities include creation of a lesson plan on phytoplankton in upwelling zones and a virtual research cruise experience for middle-school students, as well as a hands-on lab activity for a local museum focused on marine phytoplankton and the important roles they play in shaping our planet. The project examines how phytoplankton respond at the molecular and physiological level to the different UCBC stages, which seed populations (i.e., surface versus subsurface) contribute most to phytoplankton blooms during upwelling events of varying intensity, how phytoplankton elemental compositions are altered throughout UCBC stages, and how future predicted ocean conditions will affect the phytoplankton responses to UCBC conditions. This project contains both laboratory and fieldwork. In the laboratory, phytoplankton isolates recently obtained from upwelling regions are exposed to simulated UCBC conditions to examine changes in gene expression, growth and photosynthetic characteristics and elemental composition. Cultures are subjected to both current and future ocean conditions, including reduced iron availability and higher CO2. In the field, research cruises within upwelling regions study the dynamics of natural phytoplankton communities (both surface and subsurface) experiencing upwelling and relaxation and within simulated upwelling incubation experiments. Knowledge of how phytoplankton are affected by UCBC conditions at an integrated molecular, physiological and elemental level under both current and future scenarios is imperative for the proper conservation and management of these critically important ecosystems.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.