Dr. Michelle Gehringer, RPTU

Ancient Influencers: How Cyanobacteria changed the wO₂rld

Oxygenation of the Earth’s atmosphere by Cyanobacteria occurred ca 2.4 Ga ago, during the Great Oxygenation Event (GOE). The crown group of Cyanobacteria however, evolved ~3.2-2.8 Ga, with geological evidence of phototrophic mats and stromatolites thought to contain cyanobacteria, dates back to at least 3.2 Ga. Here I present insights gained from simulation experiments, and fieldwork, on how Cyanobacteria have adapted to, and shaped the Earth throughout history. 

Nutrient availabilities, such as nitrogen, iron and phosphates, as well as environmental conditions, influence cyanobacterial oxygenic photosynthesis, under both the anoxic atmospheric conditions of early Earth and present-day oxygen rich conditions. Enhanced levels of atmospheric CO₂ also impact the growth and physiology of Cyanobacteria. Our work highlights the effects of climate change on these essential global primary producers, particularly within the terrestrial biosphere. 

By increasing the alkalinity of their environment during photosynthesis, Cyanobacteria enhance rock dissolution. Our current research focuses on exploiting cyanobacteria to enhance rock weathering, thereby increasing carbon drawdown from the atmosphere. By mitigating the effects of climate change and once again altering the Earth’s atmosphere, Cyanobacteria demonstrate their significant influence on the habitability of our planet.