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.

在地球大部分历史上，大气和海洋中的氧气（O2）水平太低，无法支持植物和动物生命。蓝细菌是微生物，通过通过光合作用产生O2来使大气氧化，从而实现了当今存在的生命。但是，驱动大气中氧气升​​高的特定因素尚不清楚。特别是，在低-O2，富含硫化物的条件下，在地球的进行性氧合过程中广泛普遍存在的蓝细菌O2产生的控制知之甚少。该项目将研究现代蓝细菌垫子中的光，硫化氢，O2生产和微生物学之间的相互作用，这些垫子在模仿早期地球的条件下蓬勃发展。研究和结果将纳入招募，支持和保留代理学生中代表性不足的学生的努力，以旨在多样化劳动力。为了传播所学的经验教训，这项外展努力的结果将通过Thunder Bay National Marine Sanctuary的游客中心与公众共享，该访客在会议上发表并在教育杂志上发表。最后，这个跨学科项目将在美国之间建立密切的国际科学合作。该项目将研究在低O2和硫酸条件下通过蓝细菌垫对氧气（O2）生产的地球学控制。将解决三个中心问题，以揭示耦合的微生物和地球化学过程。首先，光和硫化物及其相互作用如何控制氧和无氧光合作用的平衡？其次，这些光合作用模式的观察到的转移是如何由代谢途径和不同蓝细菌种群活性的？第三，这些光合作用模式如何影响硫化物产生的速率，这可以代表有关氧和无氧光合作用平衡的反馈？解决这些问题的综合方法的总体目标是揭示特定的微生物种群，代谢途径和基础生物地球化学的地球化学过程。中辅中心中的受控实验将用于在DIEL循环中跟踪氧合和无氧光合作用的速率作为光，硫化物和MAT结构的函数。同时，最先进的“ OMIC”方法将在这些微生物群落中，在DNA，RNA和蛋白质水平上，在这些微生物群落中的代谢途径动力学提供前所未有的观点。将使用相同的实验框架来测量整个DIEL周期中硫酸盐减少细菌的代谢活性。这些异位实验将通过现场研究和直接测量垫子的原位测量植根于现实中，以平行微型培训地球化学参数的变化，代谢过程评估和蛋白质组织分析。更广泛地说，该项目将通过组建具有多种专业知识的跨学科团队来提高对微生物地球化学的理解，以将地球化学过程与微生物种群和代谢途径联系起来，并在DNA，RNA和蛋白质水平上与前所未有的分辨率联系起来。

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.