New approaches for understanding group-specific phytoplankton photosynthesis in mixed populations

了解混合种群中特定群体浮游植物光合作用的新方法

• 批准号: NE/X009742/1
• 负责人: Colin Brownlee
• 金额: $ 10.27万
• 依托单位: Marine Biological Association of the United Kingdom
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX009742%2F1
• 关键词: New; approaches; understanding; group; specific

The marine phytoplankton represent globally important components of the Earth's biogeochemical cycles. Phylogenetically diverse, they exhibit wide variations in physiological strategies in order to maximize resource utilization in complex and dynamic communities. Chlorophyll fluorescence-based photosynthetic efficiency measurements are widely used to assess the physiological status of phytoplankton populations, providing critical information on resource use that underpins population growth, seasonal succession and competition. Photosynthetic efficiency is normally monitored in "bulk" natural population samples by the use of fluorometry (pulse amplitude modulated (PAM) fluorometry or fast repetition rate fluorometry (FRRF)). However these approaches suffer a major drawback in that they do not provide information on species- or group-specific photosynthesis that that is needed to understand community dynamics in mixed populations. Such limitations can be overcome by the use of microscopy-based PAM imaging approaches that can monitor the photosynthetic efficiency of single identified cells. However, this approach is severely limited in natural phytoplankton populations by the number of cells (typically tens of cells) that can be analyzed in a typical microscopic field of view. The Mesolens is a highly sophisticated unique microscope that produces aberration-free wide field low magnification (x4) images but with the resolving power and light collecting properties of a x40 objective, allowing the simultaneous imaging of many thousands of cells, each with sub-cellular resolution. We propose to adapt our existing Mesolens to carry out single cell PAM imaging of mixed natural populations, providing a new tool to gain unprecedented species- or group- specific information on phytoplankton photosynthetic performance. Together with a novel method for concentrating viable phytoplankton cells for in situ physiological studies we will aim to provide better mechanistic understanding of phytoplankton succession and competition. Study sites will include: 1). The Western Channel Observatory station L4 Weekly fresh samples will allow detailed studies of seasonal succession. 2). An exciting opportunity to place this equipment on the newly commissioned Tara International Polar Ice Station that is planned to carry out annual winter north-south Arctic ice drifts through the Arctic winters over a 25 year period. We expect that the technological developments achieved with this project will have far broader application in a range of coastal, oceanographic and freshwater phytoplankton research.

海洋浮游植物是地球生物地球化学循环的重要组成部分。系统发育多样，它们在生理策略上表现出广泛的变化，以最大限度地利用复杂和动态的社区资源。基于叶绿素荧光的光合效率测量被广泛用于评估浮游植物种群的生理状况，提供有关资源利用的关键信息，这些信息是种群增长、季节性演替和竞争的基础。光合作用效率通常通过使用荧光测定法（脉冲幅度调制（PAM）荧光测定法或快速重复频率荧光测定法（FRRF））在“批量”天然群体样品中监测。然而，这些方法遭受一个主要的缺点，因为它们不提供信息的物种或组特定的光合作用，这是需要了解在混合种群的群落动态。这种限制可以通过使用基于显微镜的PAM成像方法来克服，该方法可以监测单个识别细胞的光合效率。然而，这种方法在自然浮游植物种群中受到可以在典型的显微镜视野中分析的细胞数量（通常为数十个细胞）的严重限制。Mesolens是一种高度复杂的独特显微镜，可产生无像差的宽视场低放大率（x4）图像，但具有x40物镜的分辨率和集光特性，允许同时对数千个细胞进行成像，每个细胞都具有亚细胞分辨率。我们建议调整我们现有的Mesolens进行混合自然种群的单细胞PAM成像，提供了一种新的工具，以获得前所未有的物种或群体特定的信息浮游植物光合性能。再加上一种新的方法，集中活浮游植物细胞的原位生理研究，我们的目标是提供更好的浮游植物演替和竞争机制的理解。研究中心将包括：1）。西海峡天文台L4站每周新鲜的样本将允许季节性演替的详细研究。2）。这是一个令人兴奋的机会，可以将该设备放置在新启用的塔拉国际极地冰站上，该冰站计划在25年的时间里每年进行冬季北极南北冰漂移。我们预计，这一项目所取得的技术发展将在沿海、海洋和淡水浮游植物研究方面有更广泛的应用。