Expanding the Bio in Biogeochemistry: Cyanobacteria and the Great Oxygenation Event.

扩展生物地球化学中的生物：蓝藻和大氧化事件。

• 批准号: 276888694
• 负责人: Dr. Michelle Gehringer
• 金额: --
• 依托单位: Fachgebiet Pflanzenökologie und Systematik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/276888694?language=en
• 关键词: Expanding; Bio; Biogeochemistry; Cyanobacteria; Great

The Great Oxygenation Event (GOE), whereby the early Earths atmosphere was oxygenated, was thought to be a single step event occurring about 2.3 Ga. Recent evidence suggests however that niches of raised oxygen levels existed prior to this, approximately 3 Ga. Cyanobacteria, by virtue of oxidative photosynthesis, are considered a key contributor to atmospheric oxygenation. Life on early Earth is evidenced with scant stromatolitic formations and microbial mats from sedimentary rocks dating from the Archean. Phylogenetic analysis of modern-day Cyanobacteria, using many genes and molecular clock algorithms, have identified ancient lineages of Cyanobacteria that originated prior to and after the GOE. Whether the signature molecules and profiles currently utilised in biogeochemistry and geomicrobiology could actually be generated by ancient Cyanobacteria under the conditions thought to have existed during the Archean, has not been determined. Our project will address this research gap by assessing the growth responses of modern day descendants of ancient cyanobacterial lineages under reduced O2 levels, in both marine and freshwater species and to correlate the obtained mineralogic data, specifically that pertaining to carbonate and iron cycling, with the existing biogeochemical records. We thereby aim to integrate the existing biogeochemical record and cyanobacterial phylogenetic history with ecophysiological studies and mineralogic analysis of modern-day analogue micro-organisms under conditions thought to have existed towards the end of the Archean, answering the question: How did Cyanobacteria affect the oxygenation of the early Earths atmosphere?

大氧化事件（GOE），即早期地球大气被氧化的事件，被认为是发生在2.3 Ga左右的单步事件。然而，最近的证据表明，在此之前，大约3千年，氧含量升高的生态位就存在了。蓝藻，凭借氧化光合作用，被认为是大气氧化的关键贡献者。从太古代沉积岩中发现的叠层石地层和微生物席可以证明早期地球上有生命。现代蓝藻的系统发育分析，使用许多基因和分子时钟算法，已经确定了在GOE之前和之后起源的古老蓝藻谱系。目前在生物地球化学和地球微生物学中使用的特征分子和剖面是否实际上是由古代蓝藻在被认为存在于太古代的条件下产生的，还没有确定。我们的项目将通过评估海洋和淡水物种中古代蓝藻谱系的现代后代在低氧水平下的生长反应，并将获得的矿物学数据，特别是与碳酸盐和铁循环有关的数据，与现有的生物地球化学记录相关联，来解决这一研究缺口。因此，我们的目标是将现有的生物地球化学记录和蓝藻的系统发育历史与现代模拟微生物的生态生理学研究和矿物学分析结合起来，在被认为存在于太古代末期的条件下，回答这个问题：蓝藻是如何影响早期地球大气的氧合作用的？