Tracking the emergence oxygenic photosynthesis with metal isotopes: A case study from the Pongola Supergroup

用金属同位素追踪氧气光合作用的出现：来自 Pongola 超群的案例研究

• 批准号: 1144317
• 负责人: Noah Planavsky
• 金额: $ 12.75万
• 依托单位: Planavsky Noah J
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2014-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1144317&HistoricalAwards=false
• 关键词: Tracking; emergence; oxygenic; photosynthesis; metal

Dr. Noah Planavsky has been awarded an NSF Earth Sciences Postdoctoral Fellowship in order to pinpoint the emergence of oxygenic photosynthesis, hosted by the California Institute of Technology. The chemical composition of the ocean has changed dramatically with the gradual oxidation of the Earth's surface. Undoubtedly the single most important event in Earth's progressive oxygenation was the development of oxygenic photosynthesis, which relies only on the ubiquitous molecules carbon dioxide and water, and allowed organisms to pioneer essentially every part of the Earth reached by sunlight. The success of this metabolism is reflected in the abundance of its waste product - molecular oxygen. Despite detailed investigations over the past 50 years, there is still intense debate about the timing of the evolution of oxygenic photosynthesis, with common estimates spanning over one billion years. The proposed work will use emerging heavy metal isotope systems to track the rise of oxygenic photosynthesis. In this study, unique properties of the molybdenum (Mo) and chromium (Cr) isotope systems will be utilized to shed light on manganese (Mn) cycling in the Earth's early oceans. Investigation of Mn oxidation is essential since other redox transformations (e.g., iron oxidation) may take place in oxygen-free conditions. The study will focus on rocks deposited from 3.2 to 2.5 billion years ago, spanning the range of time during which biological oxygen production is most typically predicted to have evolved. In addition, Dr. Planavsky will carry out educational activities by engaging undergraduate students in the investigation. Pinpointing the onset of oxygen production is central to understanding the tempo of biological evolution, and will provide important insights into planetary evolution in general. Further, given the importance of oxygenic photosynthesizers in controlling Earth's redox state and the carbon cycle, addressing the question of whether or not there was oxygen production in the mid-Archean will serve as a grounding point for understanding all major biogeochemical cycles on the early Earth.

Noah Planavsky博士被授予NSF地球科学博士后研究金，以查明由加利福尼亚理工学院主持的氧合光合作用的出现。随着地球表面的逐渐氧化，海洋的化学成分发生了巨大变化。毫无疑问，地球渐进式充氧中最重要的事件是氧合光合作用的发展，它仅依赖于无处不在的分子二氧化碳和水，并允许生物体开拓地球的每个部分。这种新陈代谢的成功反映在其丰富的废物 - 分子氧中。尽管在过去的50年中进行了详细的调查，但仍然存在激烈的辩论，就氧合光合作用的演变时间的发展存在激烈的争论，共同估计占十亿年。拟议的工作将使用新兴的重金属同位素系统来跟踪氧合光合作用的兴起。在这项研究中，将利用钼（MO）和铬（CR）同位素系统的独特特性来阐明地球早期海洋中锰（MN）循环。 MN氧化的研究至关重要，因为其他氧化还原转化（例如铁氧化）可能在无氧条件下进行。该研究将重点放在3.2亿年前沉积的岩石上，涵盖生物氧产生最常进化的时间范围。此外，Planavsky博士将通过让本科生参与调查来开展教育活动。确定氧生产的发作对于理解生物进化的节奏至关重要，并将提供一般的行星进化的重要见解。此外，鉴于氧光合物在控制地球的氧化还原状态和碳周期中的重要性，解决了当时中期是否存在氧气产生的问题，将作为理解所有早期地球上所有主要生物地球化学周期的基础。