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Collaborative Research: RUI: OCE-BO: Biogeochemistry of diurnal vertical migration in microbial mats of Lake Huron’s sinkholes.

合作研究：RUI：OCE-BO：休伦湖污水坑微生物垫中昼夜垂直迁移的生物地球化学。

基本信息

批准号：
2045972
负责人：
Dale Casamatta
金额：
$ 8.85万
依托单位：
University of North Florida
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-02-15 至 2024-01-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2045972&HistoricalAwards=false
关键词：
Collaborative Research RUI OCE BO

项目摘要

Modern-day microbial mats living on the bottom of sinkholes underneath Lake Huron experience an oxygen-poor, sulfur-rich environment resembling life on early Earth. These mat worlds are dominated by motile filaments of microbes that variably use sunlight and chemicals in their daily routines and offer opportunities for discovering novel microorganisms and ecosystem processes. Recently, complex patterns of daily vertical migration has been observed in the field, suggesting different microbes migrate vertically to the surface of the mat during daylight and nighttime. This project is unraveling the who, why and how of daily microbial migration through integration of microscopy, cultures, molecular approaches, and process rate measurements in response to changing gradients of light, sulfide and oxygen over the day-night cycle. This project places the vertical migration of microbial mats into a broader geobiological context through comparisons with other globally distributed cyanobacterial mat systems such as terrestrial springs and ice-covered Antarctic lakes. Furthermore, the diverse and versatile sinkhole mats may serve as a useful working model for robotic exploration of similar life in extraterrestrial waters like that of Jupiter’s Europa or Saturn’s Enceladus. This project is generating compelling student projects, attracting public imagination, and fueling active collaboration between two predominantly undergraduate institutions and a National Marine Sanctuary.The functioning of cyanobacteria under sulfidic, low O2-conditions is a major gap in our understanding of Earth’s oxygenation in the past. Recently, time-lapse images of diel vertical migration (DVM) were collected revealing alternating waves of vertically migrating photosynthetic and chemosynthetic filaments that followed daily fluctuating light in microbial mats in Lake Huron’s sinkholes; observations corroborated with intact mats under simulated day-night conditions in the laboratory. Such synchronized diel movement, might have played a critical role in optimizing photosynthesis, chemosynthesis, carbon burial, and oxygenation during the Precambrian. This project is evaluating the taxa involved in DVM and is probing geobiological controls on DVM under low-O2, sulfidic conditions using macro- and microscopic imaging, physico-chemical microprofiling, culturing, genetics, and allelopathic studies. Three central issues are being addressed: (1) what taxa are responsible for the DVM? (2) how and why do they perform DVM? and (3) what are the ecosystem consequences of DVM community and activity synergies? The project is revealing specific microbial populations, metabolic pathways, and geochemical processes that underpin mat biogeochemistry over the diel cycle. Studying microbial communities that have regular and measurable daily rhythms in processes that can also be tracked at micrometer scales yields an unprecedented view of the molecular underpinnings of microbial mat biogeochemistry and lays the foundation for future studies aimed at re-defining the role of autotrophic communities in ancient seas and modern 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.

生活在休伦湖下天坑底部的现代微生物垫经历了一个贫氧，富硫的环境，类似于早期地球上的生命。这些垫子世界由微生物的运动细丝主导，它们在日常生活中消耗阳光和化学物质，并为发现新的微生物和生态系统过程提供了机会。最近，在该领域已经观察到复杂的日常垂直迁移模式，这表明不同的微生物在白天和夜间垂直迁移到垫的表面。该项目正在通过整合显微镜，培养物，分子方法和过程速率测量来揭示日常微生物迁移的人，原因和方式，以应对昼夜周期中光，硫化物和氧气的变化梯度。该项目通过与其他全球分布的蓝藻垫系统（如陆地泉水和冰封的南极湖泊）进行比较，将微生物垫的垂直迁移置于更广泛的地球生物学背景下。此外，多样化和多功能的天坑垫可以作为一个有用的工作模型，机器人探索类似的生命在外星沃茨，如木星的欧罗巴或土星的恩克拉多斯。这个项目正在产生引人注目的学生项目，吸引公众的想象力，并推动两个主要的本科院校和国家海洋保护区之间的积极合作。蓝藻在硫化物，低O2-条件下的功能是我们过去对地球氧化的理解的一个主要差距。最近，延时图像昼夜垂直迁移（DVM）的收集揭示交替波的垂直迁移光合和化学合成丝，随后每天波动的光在微生物垫在休伦湖的天坑;观察证实与完整的垫在实验室模拟昼夜条件下。这种同步的昼夜运动，可能在前寒武纪优化光合作用，化学合成，碳埋藏和氧化中发挥了关键作用。该项目正在评估DVM中涉及的类群，并正在利用宏观和微观成像、物理化学微观分析、培养、遗传学和化感作用研究，探索在低氧、硫化物条件下对DVM的地球生物学控制。三个中心问题正在解决：（1）什么分类群负责DVM？(2)他们如何以及为什么执行DVM？DVM社区和活动协同作用的生态系统后果是什么？该项目揭示了特定的微生物种群，代谢途径和地球化学过程，这些过程是昼夜循环中物质地球化学的基础。研究微生物群落，这些微生物群落在可以在微米尺度上追踪的过程中具有规律和可测量的每日节律，产生了对微生物垫地球化学分子基础的前所未有的看法，并为未来旨在重新研究微生物垫地球化学的研究奠定了基础。该奖项反映了NSF的法定使命，并通过评估被认为值得支持使用基金会的知识价值和更广泛的影响审查标准。