Collaborative Research: Revealing the interplay between light, sulfur cycling, and oxygen production in cyanobacterial mats

合作研究：揭示蓝藻垫中光、硫循环和氧气产生之间的相互作用

• 批准号: 1637066
• 负责人: Gregory Dick
• 金额: $ 38.72万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1637066&HistoricalAwards=false
• 关键词: Collaborative; Research; Revealing; interplay; between

For most of Earth's history, oxygen (O2) levels in the atmosphere and oceans were too low to support plant and animal life. Cyanobacteria are microorganisms that were responsible for oxygenating the atmosphere by producing O2 via photosynthesis, thus enabling life as it is exists today. However, the specific factors that drove the rise of oxygen in the atmosphere are unknown. In particular, little is known about the controls on cyanobacterial O2 production under the low-O2, sulfide-rich conditions that were widespread during Earth?s progressive oxygenation. This project will study the interplay between, light, hydrogen sulfide, O2 production, and microbiology in modern cyanobacterial mats that thrive under conditions that mimic those of the early Earth. The research and results will be integrated into efforts to recruit, support, and retain underrepresented students in the geosciences in an effort aimed at diversifying the workforce. In order to disseminate lessons learned, results of this outreach effort will be shared with the public through the visitor center at the Thunder Bay National Marine Sanctuary, presented at conferences and published in an education journal. Finally, this interdisciplinary project will establish a close international scientific collaboration between the U.S. and Germany. This project will investigate geobiological controls on oxygen (O2) production by cyanobacterial mats under low-O2 and sulfidic conditions. Three central questions will be addressed to reveal the coupled microbial and geochemical processes. First, how do light and sulfide and their interactions control the balance of oxygenic and anoxygenic photosynthesis? Second, how are the observed shifts in these photosynthetic modes underpinned by metabolic pathways and activity of different cyanobacterial populations? Third, how do these photosynthetic modes affect the rate of sulfide production, which could represent a feedback on the balance of oxygenic and anoxygenic photosynthesis? The overall goal of the integrated approach behind addressing these questions is to reveal specific microbial populations, metabolic pathways, and geochemical processes that underpin mat biogeochemistry. Controlled experiments in mesocosms will be used to track rates of oxygenic and anoxygenic photosynthesis as a function of light, sulfide, and mat structure over a diel cycle. In parallel, state-of-the-art "omics" approaches will provide an unprecedented view of the dynamics of metabolic pathways in these microbial communities at the level of DNA, RNA, and protein. The same experimental framework will be used to measure the metabolic activity of sulfate reducing bacteria under oxygenic and anoxygenic photosynthesis across the diel cycle. These ex situ experiments will be rooted in reality via field investigations and direct measurements of mats in situ for parallel microprofiling of changes in geochemical parameters, assessment of metabolic processes, and proteomic analyses. More broadly, this project will advance the understanding of microbial geochemistry by forming an interdisciplinary team with diverse expertise to link geochemical processes to microbial populations and metabolic pathways with unprecedented resolution at the level of DNA, RNA, and protein.

在地球历史的大部分时间里，大气和海洋中的氧气 (O2) 水平太低，无法支持植物和动物的生命。蓝细菌是通过光合作用产生氧气为大气充氧的微生物，从而使生命得以存在。然而，导致大气中氧气含量上升的具体因素尚不清楚。特别是，人们对在地球渐进氧化过程中普遍存在的低氧、富含硫化物条件下蓝藻产生氧气的控制知之甚少。该项目将研究现代蓝藻垫中光、硫化氢、氧气产生和微生物学之间的相互作用，这些藻垫在模仿早期地球的条件下茁壮成长。研究和结果将被纳入招募、支持和留住地球科学领域代表性不足的学生的努力中，以实现劳动力多元化。为了传播经验教训，这一外展工作的结果将通过桑德湾国家海洋保护区的游客中心与公众分享，并在会议上介绍并在教育期刊上发表。最后，这个跨学科项目将在美国和德国之间建立密切的国际科学合作。该项目将研究低 O2 和含硫条件下蓝藻垫产生氧气 (O2) 的地球生物学控制。将解决三个核心问题以揭示微生物和地球化学的耦合过程。首先，光和硫化物及其相互作用如何控制有氧和无氧光合作用的平衡？其次，观察到的这些光合作用模式的变化是如何受到不同蓝藻种群的代谢途径和活动的支持的？第三，这些光合作用模式如何影响硫化物的产生速率，这可以代表对有氧和无氧光合作用平衡的反馈？解决这些问题背后的综合方法的总体目标是揭示支撑垫生物地球化学的特定微生物种群、代谢途径和地球化学过程。中生态系统中的受控实验将用于跟踪昼夜循环中光、硫化物和席结构的函数的含氧和缺氧光合作用速率。与此同时，最先进的“组学”方法将为这些微生物群落在 DNA、RNA 和蛋白质水平上的代谢途径动态提供前所未有的视角。相同的实验框架将用于测量硫酸盐还原细菌在整个昼夜循环的有氧和无氧光合作用下的代谢活性。这些异位实验将通过现场调查和原位垫的直接测量来扎根于现实，以便对地球化学参数的变化进行并行微观分析、代谢过程评估和蛋白质组分析。更广泛地说，该项目将组建一个具有不同专业知识的跨学科团队，以前所未有的 DNA、RNA 和蛋白质水平分辨率将地球化学过程与微生物种群和代谢途径联系起来，从而增进对微生物地球化学的理解。

项目成果

Nitrate respiration and diel migration patterns of diatoms are linked in sediments underneath a microbial mat

硅藻的硝酸盐呼吸和昼夜迁移模式与微生物垫下的沉积物有关

• DOI: 10.1111/1462-2920.15345
• 发表时间: 2020
• 期刊: Environmental Microbiology
• 影响因子: 5.1
• 作者: Merz, Elisa;Dick, Gregory J.;de Beer, Dirk;Grim, Sharon;Hübener, Thomas;Littmann, Sten;Olsen, Kirk;Stuart, Dack;Lavik, Gaute;Marchant, Hannah K.
• 通讯作者: Marchant, Hannah K.

Sedimentary pyrite sulfur isotope compositions preserve signatures of the surface microbial mat environment in sediments underlying low‐oxygen cyanobacterial mats

沉积黄铁矿硫同位素成分保留了低氧蓝藻垫下沉积物中表面微生物垫环境的特征

• DOI: 10.1111/gbi.12466
• 发表时间: 2021
• 期刊: Geobiology
• 影响因子: 3.7
• 作者: Gomes, Maya L.;Klatt, Judith M.;Dick, Gregory J.;Grim, Sharon L.;Rico, Kathryn I.;Medina, Matthew;Ziebis, Wiebke;Kinsman‐Costello, Lauren;Sheldon, Nathan D.;Fike, David A.
• 通讯作者: Fike, David A.